Sound attenuation design support system and vibration reduction design support system

Abstract

To provide a sound attenuation design support system which suppresses equipment noise generated from a building facility.SOLUTION: A sound attenuation design support system 1 includes: a database 2 in which a propagation loss for each frequency band from an installation position at which a sound source within a building facility is installed to a sound receiving point, a noise reduction amount and installation costs for each frequency band of each of multiple types of silencers, a power level for each frequency band of each sound source, and a noise threshold value of a sound pressure level at each of the sound receiving points are set as design conditions; and an installation plan formulation unit 3 which applies an evolutionary computing method, so that the sound pressure levels at all sound receiving points are below the noise threshold value of the sound receiving point, and the total cost of installing the silencers is reduced, based on the propagation loss from the sound source to the sound receiving point, the noise reduction amount of the silencers, the installation costs and the power level of each sound source, selects and allocates an installation position at which the sound source is installed from a plurality of installation positions, and the silencer installed with respect to the sound source from the multiple types of silencers, for each sound source, and formulates an installation plan of the sound source and the silencers.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a noise reduction design support system for equipment noise countermeasures, which presents recommended measures to suppress equipment noise generated within building facilities, and a vibration isolation design support system for equipment vibration countermeasures. [Background technology]

[0002] In buildings and facilities such as factories, waste disposal plants, and other plants that are equipped with many pieces of equipment, noise generated by the equipment must be kept below the established regulatory limits at the boundary lines of the building or facility. Therefore, if, at the planning stage of a building or facility, it is anticipated that noise levels at the boundary lines of the facility will exceed the regulatory limits, noise control measures must be implemented.

[0003] Regarding measures against such noise, the following Patent Documents 1 to 3 are disclosed. Patent Document 1 discloses a configuration in which the propagation distance of noise generated from a noise source and the sound pressure level attenuated by soundproofing equipment are calculated for each sampling point, the sound pressure level values ​​calculated for each noise source are added up for each sampling point, and data corresponding to the added value is displayed together with the noise source and soundproofing equipment for each sampling point. Patent Document 2 discloses a configuration in which the vibration noise transmission state and its contribution rate when equipment is in actual operation are estimated, and a post-vibration noise problem prevention probability table is generated based on a vibration noise transmission path probability inference model, which correlates whether or not pre-emptive measures are implemented with the post-problem occurrence prevention rate, and a cost table is generated based on an input pre- and post-cost list consisting of the pre-costs for implementing each vibration noise problem prevention measure and the post-costs for after the problem occurs, and the optimal application measure, along with the predicted vibration noise level when the optimal application measure is implemented, are presented to the user based on the post-vibration noise problem prevention probability table and the cost table. Patent Document 3 discloses a configuration in which the vibration noise transmission state and its contribution rate when equipment is in actual operation are estimated, a vibration noise problem prevention probability table is generated that correlates the presence or absence of proactive measures with the subsequent problem occurrence prevention rate based on a vibration noise transmission path probability inference model, a cost table is generated based on an input pre- and post-cost list consisting of the pre-costs for implementing each vibration noise problem prevention measure and the post-costs for after the problem occurs, a payoff table relating to expected costs is generated based on the vibration noise problem prevention probability table and the cost table, and a payoff table relating to expected costs for each option for action selection in an input game tree, which is a tree structure of action selection and situational judgment in each process of product design and production, is generated and presented to the user.

[0004] The targets for noise control measures include the equipment that is the source of the noise and the noise propagation path from the equipment to the site boundary. For example, it is common to reduce noise from equipment that is the source of the noise by attaching a silencer to the equipment. However, the frequency characteristics of noise generated by different types of equipment vary. Similarly, the frequency characteristics of the sounds that silencers are intended to silence vary depending on the type of silencer. For this reason, when installing a silencer for a piece of equipment, the type must be carefully considered. Here, the number of pieces of equipment requiring measures and the number of points along the site boundary where noise must be evaluated typically number in the tens or even hundreds. For this reason, it is virtually impossible for a human being to select the appropriate type of silencer for each piece of equipment, taking into account the cost of installing the silencer, so that noise levels at all points along the site boundary are below the regulatory limit.

[0005] Furthermore, when designing a building or facility, the location of each piece of equipment within the building or facility is determined during the equipment design stage. Each piece of equipment that acts as a sound source emits a different sound power level depending on its type and characteristics. Therefore, in order to reduce noise at the site boundary, if we simply consider attenuation over distance, it is preferable to locate (potential) sound sources with a higher power level as far away from the site boundary as possible. However, in reality, in addition to sound wave attenuation over distance, if there are obstacles between the sound source and the property boundary, phenomena such as reflection and diffraction occur, making the propagation characteristics from the sound source to the property boundary complex. Furthermore, if there are a large number of pieces of equipment to be installed, the number of locations where the equipment can be installed will also increase. For this reason, it is not easy for a human to select locations for all sound sources (or potential equipment) so that noise levels at all points along the property boundary are below the regulatory limit.

[0006] In this regard, the above-mentioned Patent Document 1 displays the sound pressure level at the sampling point, but is not applicable to selecting the installation location of equipment that will be a sound source or the type of silencer. Also, in Patent Documents 2 and 3, the user prepares a list of applicable measures in advance and generates a benefit table based on the costs of the applicable measures, and it is difficult to use these technologies to automatically formulate installation plans for equipment that will be a sound source or silencers. When installing a sound source in a building facility and installing a silencer for the sound source, it is desirable to automatically calculate an installation plan that keeps the sound pressure level at the sound receiving point below the noise threshold and reduces the cost of installing the silencer.

[0007] A similar need exists for vibration. That is, when installing a vibration source within a building facility and installing vibration-isolating materials for the vibration source, it is desirable to automatically calculate an installation plan that will keep the vibration level at the receiving point below the vibration threshold and reduce the installation cost of the vibration-isolating materials. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Patent No. 2-287770 [Patent Document 2] Japanese Patent Application Publication No. 2019-106032 [Patent Document 3] Japanese Patent Application Publication No. 2019-191851 Summary of the Invention [Problem to be solved by the invention]

[0009] The problem to be solved by the present invention is to provide a sound absorbing design support system that automatically calculates an installation plan when a sound source is installed within a building facility and a silencer is installed for the sound source, such that the sound pressure level at the sound receiving point is below the noise threshold and the installation cost of the silencer is low, and a vibration isolation design support system that automatically calculates an installation plan when a vibration source is installed within a building facility and a vibration isolation material is installed for the vibration source, such that the vibration level at the vibration receiving point is below the vibration threshold and the installation cost of the vibration isolation material is low. [Means for solving the problem]

[0010] The present inventors have come up with the present invention by focusing on the fact that, as a sound suppression design support system for suppressing equipment noise generated within building facilities, when selecting recommended measures for equipment noise control that will keep sound pressure levels at all sound receiving points below the noise threshold and have a small total cost for installing silencers, based on the propagation loss from multiple installation positions where sound sources are to be installed to the sound receiving points, the noise reduction amount and installation cost of silencers, and the power level of each sound source for each frequency band, by using an evolutionary computing method, it is possible to quickly select, for each sound source, an appropriate installation position for the sound source from multiple installation positions and an appropriate silencer from multiple types of silencers, and present installation plans for the sound sources and silencers. In addition, the vibration isolation design support system converts the equipment noise and sound pressure in the noise reduction design support system into equipment vibration and vibration level, and also converts the sound source into a vibration source and the silencer into a vibration isolation material, thereby presenting recommended measures to suppress equipment vibration. In order to solve the above problems, the present invention employs the following means. That is, the noise reduction design support system of the present invention is a noise reduction design support system that supports noise reduction design for suppressing equipment noise generated from a building facility, and is characterized by comprising: a database in which the propagation loss for each frequency band from each of a plurality of installation positions to be targeted for installing sound sources in the building facility to each of the sound receiving points, the noise reduction amount and installation cost for each of a plurality of types of silencers for each frequency band, the power level for each of the sound sources for each frequency band, and the noise threshold value of the sound pressure level at each of the sound receiving points are set as design conditions; and an installation plan formulation unit that applies an evolutionary computing method to, for each sound source, select and assign the installation position at which the sound source is to be installed from a plurality of installation positions and the silencer to be installed for the sound source from a plurality of types of silencers, so that the sound pressure levels at all of the sound receiving points are below the noise threshold value of the sound receiving point and the total installation cost of the silencers is reduced. According to this configuration, based on the propagation loss from each of a plurality of installation positions where a sound source (or equipment that could become a sound source) is to be installed to each of the sound receiving points, the noise reduction amount and installation cost of the silencer, and the power level of the sound source, an installation plan for the sound source and the silencer is obtained by applying an evolutionary computing method to select and assign, for each sound source, an installation position for the sound source from a plurality of installation positions and a silencer to be installed for the sound source from a plurality of types of silencer, so that the sound pressure levels at all of the sound receiving points will be below the noise threshold for the sound receiving points and the total installation cost of the silencer will be small. Thus, when installing a sound source in a building facility and installing a silencer for the sound source, it is possible to provide a noise reduction design support system that automatically calculates an installation plan for the silencer so that the sound pressure level at the sound receiving points will be below the noise threshold and the installation cost of the silencer will be small.

[0011] In one aspect of the present invention, the installation plan formulation unit has a predetermined number of pieces of design candidate data, each of the plurality of pieces of design candidate data including a correspondence relationship between each of the sound sources and the installation positions and types of mufflers assigned to each of the sound sources, and the installation plan formulation unit includes a design candidate data update unit that repeatedly updates the plurality of pieces of design candidate data by changing the correspondence relationship through selection processing, crossover processing, and mutation processing in the evolutionary computing method. According to this configuration, a predetermined number of multiple design candidate data are repeatedly updated by changing the correspondence between each sound source and the installation position and silencer type assigned to each sound source through selection processing, crossover processing, and mutation processing in the evolutionary computing method. In this way, the installation plan formulation unit treats the multiple design candidate data like chromosomes of a living organism, and by sequentially repeating selection processing, crossover processing, and mutation processing, processing progresses so that design candidate data with more appropriate assignments of installation positions and silencer types to sound sources is preferentially retained. This makes it possible to search for more ideal design candidate data and select an appropriate silencer installation plan.

[0012] In one aspect of the present invention, the installation plan formulating unit includes an initialization unit that randomly sets and initializes the installation position and the type of the silencer for each of the sound sources for each of the plurality of pieces of design candidate data; a noise level / cost calculation unit that calculates the sound pressure levels at all of the sound receiving points and the total of the installation costs of the silencers when each of the sound sources is installed at the installation position assigned in the design candidate data and when each of the sound sources is installed with the silencer of the type assigned in the design candidate data; and a noise level / cost calculation unit that calculates the sound pressure levels at all of the sound receiving points and the total of the installation costs of the silencers when each of the sound sources is installed at the installation position assigned in the design candidate data and when the silencer of the type assigned in the design candidate data is installed in the sound source. The system includes: a termination determination unit that, if any of the design candidate data has the sound pressure levels at all of the sound receiving points lower than the noise threshold values ​​of the sound receiving points, registers the design candidate data as final candidate data, and terminates the processing of the design candidate data update unit when the number of iterations in the design candidate data update unit reaches a predetermined number; and a design result output unit that selects, from the final candidate data, the data with the smallest total installation costs of the mufflers as optimal data, and displays the installation positions and types of the mufflers assigned to each of the sound sources in the optimal data, as well as the total installation costs of the mufflers. According to this configuration, if any of the updated design candidate data has sound pressure levels at all sound receiving points that are below the noise thresholds of the sound receiving points, that design candidate data is registered as final candidate data. Furthermore, when the number of iterations in the design candidate data updating unit reaches a predetermined number, the processing of the design candidate data updating unit is terminated. Then, from among the final candidate data, the data with the lowest total silencer installation cost is selected as the optimal data, and the installation positions and silencer types assigned to each sound source, as well as the total silencer installation cost, in this optimal data are displayed. In this way, it is possible to select an appropriate silencer installation plan in which sound pressure levels at all sound receiving points are below the noise thresholds of the sound receiving points and the total silencer installation cost is lowest.

[0013] In one aspect of the present invention, in the crossover processing, the design candidate data update unit updates the correspondence between the sound sources and the types of mufflers in one of the design candidate data by replacing the types of mufflers corresponding to some of the sound sources in one of the design candidate data with the types of mufflers corresponding to the some of the sound sources in another of the design candidate data, selects one or more of the installation positions, and assigns the installation positions to the sound sources so that the selected installation positions inherit the correspondence between the sound sources and the installation positions in either one of the one design candidate data or the other design candidate data, and assigns the installation positions other than the selected installation position to the sound sources to which no installation position has been assigned, among the plurality of installation positions, so that the same installation position is not assigned to different sound sources, thereby updating the correspondence between the sound sources and the installation positions in the one design candidate data. With regard to the mufflers, as described above, by replacing the type of muffler corresponding to a part of the sound source in one design candidate data with the type of muffler corresponding to the part of the sound source in another design candidate data, the correspondence between the sound source and the type of muffler in one design candidate data is updated, and the crossover process in the evolutionary computing method can be appropriately realized. In the above-described processing, as a result of the crossover processing, there is a possibility that the same type of silencer is selected and assigned to different sound sources. Since it is possible to prepare multiple silencers for each type, it is acceptable for the same type of silencer to be selected and assigned to multiple different sound sources. However, with regard to the installation location, it is physically impossible to install multiple sound sources, i.e., multiple pieces of equipment, at one installation location at the same time, so it is not permitted for the same installation location to be selected multiple times for different sound sources. In contrast, with regard to installation positions, in the above configuration, one or more installation positions are selected, and an installation position is assigned to a sound source so that the selected installation positions inherit the correspondence between the sound source and the installation position in either one of the design candidate data or the other design candidate data. Then, for sound sources to which no installation position has been assigned, an installation position other than the selected installation position is assigned from among the multiple installation positions so that the same installation position is not assigned to different sound sources, thereby updating the correspondence between the sound source and the installation position in the one design candidate data. This makes it possible to appropriately realize crossover processing in the evolutionary computing method while preventing the same installation position from being assigned to different sound sources in duplicate.

[0014] In one aspect of the present invention, the design candidate data update unit executes, in the mutation processing, a silencer type mutation processing in which, for some of the sound sources in the design candidate data, the types of the silencers corresponding to those sound sources are randomly replaced with other types of silencers, and an installation position mutation processing in which, for one randomly selected sound source and a second randomly selected sound source in the design candidate data, the corresponding installation positions are swapped with each other. With regard to the mufflers, as described above, by randomly replacing the type of muffler corresponding to some sound sources in the design candidate data with other muffler types, it is possible to appropriately realize the mutation process in the evolutionary computing method. In the above-described process, as a result of the mutation process, there is a possibility that the same type of silencer is selected and assigned to different sound sources. Since it is possible to prepare multiple silencers for each type, it is acceptable for the same type of silencer to be selected and assigned to multiple different sound sources. However, with regard to the installation location, it is physically impossible to simultaneously install multiple sound sources, i.e., multiple pieces of equipment, at one installation location, so it is not permitted for the same installation location to be selected multiple times for different sound sources. In contrast, with regard to the installation positions, in the above configuration, the corresponding installation positions of the first and second sound sources randomly selected in the design candidate data are swapped with each other. In this process, since the installation positions of the two sound sources are simply swapped, if the same installation position is not assigned to different sound sources in the original design candidate data, the same installation position will not be assigned to different sound sources even after the above process. As a result, with regard to the installation positions, it is possible to appropriately realize the mutation process in the evolutionary computing method while preventing the same installation position from being assigned to different sound sources more than once.

[0015] The vibration-proof design support system of the present invention is a vibration-proof design support system that supports vibration-proof design for suppressing equipment vibrations generated by building facilities, and is characterized by comprising: a database in which the propagation loss for each frequency band from each of a plurality of installation positions to which vibration sources within a building facility are to be installed to each of the receiving points, the vibration reduction amount and installation cost for each of a plurality of types of vibration-proof material, the power level for each frequency band of each of the vibration sources, and the vibration threshold value for the vibration level at each of the receiving points are set as design conditions; and an installation plan formulation unit that applies an evolutionary computing method to, for each vibration source, select and assign the installation position at which the vibration source is to be installed from a plurality of installation positions and the vibration-proof material to be installed for the vibration source from a plurality of types of vibration-proof material, based on the propagation loss, the vibration reduction amount, the installation cost, and the power level, so that the vibration levels at all of the receiving points are below the vibration threshold value for that receiving point and the total installation cost of the vibration-proof material is reduced. With this configuration, an installation plan for vibration sources and vibration-isolating materials is obtained by applying an evolutionary computing method to each vibration source, selecting and allocating an installation location for the vibration source from among multiple installation locations and vibration-isolating materials from among multiple types of vibration-isolating materials, based on the propagation loss from each of multiple installation locations where a vibration source (or potential equipment) is to be installed to each receiving point, the vibration reduction amount and installation cost of the vibration-isolating material, and the power level of the vibration source, so that the vibration levels at all receiving points are below the vibration threshold for that vibration source and the total installation cost of the vibration-isolating material is reduced.This makes it possible to provide a vibration-isolation design support system that, when installing vibration sources in a building facility and installing vibration-isolating materials around the vibration sources, automatically calculates an installation plan for vibration-isolating materials so that the vibration levels at the receiving points are below the vibration threshold and the installation cost of the vibration-isolating material is reduced. [Effects of the Invention]

[0016] According to the present invention, it is possible to provide a sound absorbing design support system that automatically calculates an installation plan when a sound source is installed within a building facility and a silencer is installed for the sound source, such that the sound pressure level at the sound receiving point is below the noise threshold and the installation cost of the silencer is low, and a vibration isolation design support system that automatically calculates an installation plan when a vibration source is installed within a building facility and a vibration isolation material is installed for the vibration source, such that the vibration level at the vibration receiving point is below the vibration threshold and the installation cost of the vibration isolation material is low. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a diagram showing a schematic configuration of a noise reduction design support system according to an embodiment of the present invention; [Figure 2] FIG. 10 is a diagram showing an example of a list of propagation losses for each frequency band between each of a plurality of target installation positions where a sound source is to be installed and each of the sound receiving points, which is stored in a database. [Figure 3] FIG. 10 is a diagram showing an example of a list stored in a database in which power levels for each frequency band of each piece of equipment that serves as a sound source are arranged. [Figure 4]FIG. 10 is a diagram showing an example of a list stored in a database that lists the noise reduction amount and installation costs for each frequency band of silencers that may be installed in a facility. [Figure 5] FIG. 10 is a diagram showing an example of a list of regulation values ​​(A-weighted sound pressure levels) at each sound receiving point stored in a database. [Figure 6] 1 is a flowchart showing a process flow for formulating a plan for installing a noise source facility and a silencer in a noise reduction design support system. [Figure 7] 10 is a flowchart showing the flow of processing when a sound pressure level is calculated in the noise level / cost calculation unit. [Figure 8] This shows the P design candidate data obtained by the noise level and cost calculation section. [Figure 9] 10 is a flowchart showing a processing flow when updating design candidate data in a design candidate data updating unit. [Figure 10] 10 is a flowchart showing the flow of a selection process executed by a design candidate data update unit. [Figure 11] FIG. 10 is a diagram showing an example of a roulette wheel used in the selection process, in which the probability of being selected increases in proportion to the magnitude of the objective function. [Figure 12] 10 is a flowchart showing the flow of crossover processing executed by a design candidate data update unit. [Figure 13] FIG. 10 is an explanatory diagram of an example of crossover processing related to a silencer. [Figure 14] FIG. 10 is an explanatory diagram of an example of crossover processing regarding installation positions. [Figure 15] FIG. 10 is an explanatory diagram of another example of crossover processing regarding installation positions. [Figure 16] 10 is a flowchart showing the flow of mutation processing executed by a design candidate data update unit. DETAILED DESCRIPTION OF THE INVENTION

[0018] The present invention provides a noise reduction design support system for equipment noise countermeasures that presents recommended measures to suppress equipment noise generated within building facilities, and a vibration isolation design support system for equipment vibration countermeasures that suppress equipment vibrations. The noise reduction design support system can select and present a cost-effective recommended measure plan for equipment noise control, in which equipment that will be noise sources is installed appropriately at multiple installation positions within a building facility, and various noise reduction devices are installed for all noise sources within the building facility, thereby keeping the equipment noise level below the noise threshold and reducing the total cost by combining the noise reduction devices.Furthermore, the vibration isolation design support system can select and present a cost-effective recommended measure plan for equipment vibration control, in which equipment that will be vibration sources is installed appropriately at multiple installation positions within the building facility, and various vibration isolation materials are installed for all equipment vibration within the building facility, thereby keeping the equipment vibration level below the vibration threshold and reducing the total cost by combining the vibration isolation materials. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, with reference to the accompanying drawings, an embodiment for carrying out a noise reduction design support system according to the present invention will be described.

[0019] FIG. 1 shows a schematic configuration of a noise reduction design support system according to an embodiment of the present invention. The noise reduction design support system 1 shown in Fig. 1 supports noise reduction design for suppressing equipment noise generated from multiple sound sources located within a building facility. When multiple pieces of equipment that serve as noise sources are to be installed within a building facility, the noise reduction design support system 1 selects, for each sound source, an installation position for the equipment that emits the sound source from multiple installation positions to which the equipment is to be installed, and selects a silencer to be installed for the sound source from multiple types of silencers, thereby formulating an installation plan regarding where in the building facility the equipment that emits the sound source should be installed and which pieces of equipment should have a silencer installed for, so that the sound pressure level at each of multiple preset sound receiving points is below the noise threshold. Such a noise reduction design support system 1 includes the selection of the installation location for the equipment that emits the noise source as described above, and therefore can be effectively used when designing buildings and facilities, particularly when designing facilities. In some cases, the noise reduction design support system 1 can also be used after construction of the building facility has begun.

[0020] Possible noise sources include outdoor units, cooling towers, chillers, and the like that are installed outdoors. As will be described later, in this embodiment, the noise reduction design support system 1 considers the propagation loss from the installation position where the equipment that will be the sound source is installed to the sound receiving point, and formulates an installation plan for the equipment that will emit a sound source and a silencer so that the sound pressure level at each of a plurality of predetermined sound receiving points is below the noise threshold. The distance from the installation position to the sound receiving point significantly affects the value of the propagation loss. Here, if the installation position is set as an area having a certain range, such as a room or a section within a building facility, even if the installation position where the equipment that will emit a sound source is installed is specified, the value of the propagation loss will differ depending on where within the specified installation position the equipment is actually installed. Therefore, in this embodiment, the installation position where the equipment that will emit a sound source is to be installed is specified as a specific location, rather than as an area within the building facility.

[0021] In this embodiment, the power level emitted by the equipment varies depending on the type. From this perspective, it can be said that the equipment and the sound source correspond to each other. Therefore, in the following description, for example, when a sound source is described as being installed, it means that the equipment that emits the sound source is installed. In this regard, the term "installation location" accurately indicates the location within the building facility where the "equipment that emits the sound source" is to be installed, but it also indicates the location within the building facility where the "sound source" is to be installed.

[0022] Many silencers are box-shaped and made of glass wool as a sound-absorbing material and steel plates. These silencers are attached to the intake and exhaust ports of each piece of equipment, or are used to cover the entire equipment, thereby efficiently absorbing the noise generated by the equipment and reducing the noise radiated to the outside. In this embodiment, the sound receiving point is assumed to be located on the boundary line of the building facility. However, a location within the building facility where quietness is required, such as a conference room, may be used as the sound receiving point to reduce noise transmitted to the interior of the building facility. Alternatively, a point located outside the boundary line of the facility may be used as the sound receiving point. In either case, the same explanation as below is applicable.

[0023] The frequency characteristics of the noise generated by the above-mentioned equipment differ depending on the type of equipment. Similarly, the frequency characteristics of the sound to be silenced differ depending on the type of silencer. For this reason, when installing a silencer for equipment, the type must be carefully considered. Here, the number of equipment requiring measures, i.e., sound sources and sound receiving points, usually reaches tens or hundreds. For this reason, it is virtually impossible for a human being to select an appropriate type of silencer for each sound source so that the noise at all sound receiving points is below the regulatory value, while taking into account the cost of installing the silencer. Furthermore, for example, in the stage of designing the facilities of a building, the location within the building where each piece of equipment will be installed is determined. Here, the power level of the sound emitted by each piece of equipment that is a sound source varies depending on its type and characteristics. Therefore, in order to reduce noise at the boundary line of a site, it is preferable, simply put, to install (potentially becoming) a sound source with a higher power level as far away from the boundary line as possible. However, when there is a large amount of equipment to be installed, the number of locations where the equipment can be installed also increases. For this reason, it is not easy for a human to select locations for all noise sources (or potential equipment) so that noise levels at all points along the site boundary are below the regulatory limit.

[0024] The noise reduction design support system 1 in this embodiment automatically formulates installation plans for sound sources and silencers such that the sound pressure level at each sound receiving point is below the noise threshold by selecting and assigning, for each sound source, an installation position for the sound source from a plurality of installation positions and a silencer to be installed for the sound source from a plurality of types of silencers. The noise reduction design support system 1 includes a database 2 and an installation plan formulation unit 3.

[0025] Fig. 2 is a diagram showing an example of a list of propagation losses for each frequency band between each of a plurality of target installation positions for installing a sound source and each of the sound receiving points, stored in a database. Fig. 3 is a diagram showing an example of a list showing the power level for each frequency band of each piece of equipment that will be a sound source, stored in a database. Fig. 4 is a diagram showing an example of a list showing the noise reduction amount for each frequency band of a silencer that may be installed for the equipment and the installation costs, stored in a database. Fig. 5 is a diagram showing an example of a list showing the regulation value (A-weighted sound pressure level) at each sound receiving point, stored in a database. A plurality of types of design condition data are stored and set as design conditions in the database 2. The design condition data may include, for example, the propagation loss for each frequency band from each of a plurality of target installation positions for installing sound sources within a building facility to each of the sound receiving points, the power level for each frequency band of each sound source, the noise reduction amount for each frequency band of each of a plurality of types of silencers, the installation cost for each of the plurality of types of silencers, and the noise threshold value (regulation value) of the sound pressure level at each of the sound receiving points.

[0026] As shown in Figure 2, the propagation loss between each of the multiple installation positions where the sound source is to be installed and each of the sound receiving points among the design condition data indicates the value of propagation loss in each frequency band from each of the M installation positions where the sound source is installed to each of the N sound receiving points. In Figure 2, the propagation loss in the frequency band k (k = 63, 125, ..., 8k) from the installation position t (t = 1, 2, ..., M) to the sound receiving point i (i = 1, 2, ..., N) is expressed as R ki、t The propagation loss value between each installation position and each sound receiving point can be calculated using numerical analysis methods such as the time domain finite difference method, the finite element method, the boundary element method, and the extended energy integral equation method. The propagation loss value can also be calculated using the above methods at the design stage of a building facility based on the geometric conditions between the installation position and the sound receiving point and the acoustic characteristics of obstacles such as the sound transmission loss and sound absorption coefficient.

[0027] As shown in Figure 3, the power level of the sound source in the design condition data indicates the power level of each piece of equipment that is a sound source for each frequency band. In Figure 3, the power level of sound source j (j=1, 2, ..., M) in frequency band k (k=63, 125, ..., 8k) is L w k j It is expressed as: In this embodiment, the number of sound sources (i.e., equipment) to be installed and the number of installation positions where the sound sources are to be installed are both the same value M. As already explained, the installation positions are not within a range within a building facility but are specified as pinpoints at specific locations, so the number of sound sources that can be installed at one installation position is one. Therefore, in this embodiment, M sound sources (equipment that emits sound sources) are assigned and installed at each of the M installation positions without overlapping.

[0028] As shown in Fig. 4, the noise reduction amount and cost of the silencer among the design condition data indicates the noise reduction amount for each frequency band and the cost required for installation (installation cost) of each of multiple types of silencers (K types in this embodiment) that may be installed in the facility. In Fig. 4, the noise reduction amount of silencer l (l = 1, 2, ..., K) in frequency band k (k = 63, 125, ..., 8k) is R s k l and installation costs are C l are expressed as, respectively.

[0029] As shown in Figure 5, the noise threshold at the sound receiving point among the design condition data indicates the regulation value (A-weighted sound pressure level) at each sound receiving point. In Figure 5, the noise threshold at sound receiving point i (i = 1, 2, ..., N) is L Ti The regulation value as the noise threshold may be different for each sound receiving point as shown in Figure 5, or may be a common value for all sound receiving points.

[0030] The installation plan formulation unit 3 formulates installation plans for sound sources and silencers by selecting and allocating, for each sound source, an installation location from among multiple installation locations and a silencer to be installed for that sound source from multiple types of silencers, based on the propagation loss from the installation location to the sound receiving point, the noise reduction amount and installation cost of the silencer, and the power level of the sound source, so that the sound pressure levels at all sound receiving points are below the noise threshold of each sound receiving point and the total installation cost of the silencer is small. As shown in Fig. 1, the installation plan formulation unit 3 includes a parameter input unit 31, an initialization unit 32, a noise level / cost calculation unit 33, a design candidate data update unit 34, a completion determination unit 35, and a design result output unit 36. The parameter input unit 31 receives external input of parameters necessary for optimal design of a silencer. The input parameters include, for example, the number P of design candidate data, the crossover rate CR, the mutation rate MR, the number of design iterations ITER, etc., as will be described later.

[0031] The installation plan formulation unit 3 has a predetermined number of design candidate data, more specifically, the number P input to the parameter input unit 31. Each of the plurality of design candidate data includes a correspondence relationship between each of the sound sources and the installation position and type of silencer assigned to each of the sound sources. By updating the correspondence relationship between the sound source, the installation position, and the type of silencer in each of the plurality of design candidate data, an appropriate installation position and type of silencer for each sound source are searched for. The initialization unit 32 initializes (sets) a combination of installation positions for installing each of the sound sources and a combination of silencers to be placed for each of the sound sources by randomly setting an installation position and a type of silencer for each of the plurality of design candidate data. The noise level / cost calculation unit 33 calculates, for each of a plurality of design candidate data, the sound pressure levels at all sound receiving points and the sum total of the installation costs of the silencers (total cost) when each of the sound sources is installed at the installation positions assigned in the design candidate data and when a silencer of the type assigned in the design candidate data is installed for each of the sound sources.

[0032] The design candidate data update unit 34 applies an evolutionary computing method, which will be described in detail later, to the plurality of design candidate data, thereby sequentially changing the correspondence between each of the sound sources in each of the plurality of design candidate data and the installation positions and silencer types assigned to each of the sound sources, and updating the plurality of design candidate data a plurality of times. The design candidate data update unit 34 repeats the process of updating the P design candidate data by sequentially applying a selection process, a crossover process, and a mutation process, which will be described in detail later, in the evolutionary computing method, to the P design candidate data, thereby updating the correspondence between the sound source, the installation position, and the silencer type in each of the P design candidate data. In this way, the design candidate data update unit 34 searches for design candidate data that is close to ideal and suits the purpose. In this embodiment, a genetic algorithm is applied as an evolutionary computing method to select a silencer, but other methods such as differential evolution may also be used as the evolutionary computing method.

[0033] The termination determination unit 35 determines whether the design candidate data update process in the design candidate data update unit 34 satisfies a preset termination condition. Specifically, if there is at least one or more design candidate data among the design candidate data updated by the design candidate data update unit 34, and the sound pressure level at each of the sound receiving points is below the noise threshold (regulation value) of the sound receiving point at that sound receiving point, the completion determination unit 35 registers that design candidate data as final candidate data. Then, if the number of iterations of updating the multiple design candidate data by the design candidate data update unit 34 has reached a predetermined number, i.e., the number of design iterations ITER input by the parameter input unit 31, which satisfies the completion condition, the completion determination unit 35 determines that the design candidate data update process has ended. The design result output unit 36 ​​selects the final candidate data with the smallest total cost of installing the silencers as the optimum data, and displays the installation positions and types of silencers assigned to each sound source, as well as the total cost of installing the silencers, in the optimum data.

[0034] Next, the flow of processing in the noise reduction design support system 1 described above will be explained. FIG. 6 is a flowchart showing the flow of processing for formulating a silencer installation plan in the noise reduction design support system. As shown in Fig. 6, in order to formulate a silencer installation plan in the noise reduction design support system 1, first, design condition data is input to the database 2 (step S11). Specifically, the following design condition data are input to the database 2: propagation loss for each frequency band from each of a plurality of installation positions to be targeted for installing sound sources in a building facility to each of the sound receiving points (see Fig. 2), power level for each frequency band of each sound source (see Fig. 3), noise reduction amount for each frequency band of each of a plurality of types of silencers (see Fig. 4), installation cost for each of a plurality of types of silencers (see Fig. 4), and regulation value of sound pressure level at each of the sound receiving points, i.e., noise threshold value (see Fig. 5). Next, the optimization parameters required for optimally designing the silencer are input in the parameter input unit 31 (step S12). The parameters input here are, for example, the number P of design candidate data, and the crossover rate CR, mutation rate MR, and number of design iterations ITER, which will be described later.

[0035] Next, the initialization unit 32 initializes the design candidate data. More specifically, for each sound source, the initialization unit 32 initializes (sets) the installation position where the sound source is to be installed and the combination of silencers to be arranged for the sound source (step S13). As already explained, each of the plurality of design candidate data includes a correspondence relationship between each of the sound sources and the installation positions where each of the sound sources is to be installed, and a correspondence relationship between each of the sound sources and the type of silencer assigned to each of the sound sources. In this embodiment, as will be explained later with reference to Fig. 8, in addition to the above correspondence relationships, each of the design candidate data further includes the sound pressure levels at all of the sound receiving points and the total installation costs of the silencers when the sound sources are installed at the installation positions assigned in the design candidate data and the silencers of the types assigned in the design candidate data are installed at the sound sources, which are calculated by the noise level / cost calculation unit 33, which will be explained later.

[0036] The initialization unit 32 initializes each of the plurality of design candidate data by randomly setting the installation position and the type of silencer for each sound source. The initialization unit 32 randomly initializes candidate installation positions for each sound source in all design candidate data by integers from 1 to M. However, as already described, in this embodiment, M sound sources (equipment emitting the sound sources) are assigned to and installed at M installation positions without overlapping. Therefore, in each design candidate data, each sound source j (j=1, 2, ..., M) is initialized by setting a different installation position t (t=1, 2, ..., M) value to each sound source. Here, when a value t (t=1, 2, ..., M) is set for a certain sound source, it means that the sound source is installed at the installation position to which the t-th identification number is assigned.

[0037] Furthermore, the initialization unit 32 randomly initializes the candidates for silencers to be installed for each sound source of all the design candidate data with integers from 0 to K. 0 corresponds to the case where no silencer is installed. Furthermore, 1 to K correspond to the types of silencers, respectively. In other words, when a value l (l=1, 2, ..., K) is set for a certain sound source, it means that the lth type of silencer is assigned to that sound source. Regarding the mufflers, for example, multiple mufflers of the same type can be purchased, manufactured, and prepared. Therefore, unlike the case of the installation positions, the same type of muffler may be selected and assigned to multiple different sound sources in duplicate.

[0038] Next, the noise level / cost calculation unit 33 calculates the sound pressure levels at all sound receiving points when each sound source is installed at the installation position assigned in the design candidate data for each of the plurality of design candidate data and when a silencer of the type assigned in the design candidate data is installed in each sound source (step S14). FIG. 7 is a flowchart showing the flow of processing performed by the noise level / cost calculation unit when calculating sound pressure levels for design candidate data p (p=1, 2, . . . , P). In the following, the design position to which sound source j (j = 1, 2, ..., M) is assigned in design candidate data p (p = 1, 2, ..., P) is denoted by X p、j In this case, for each design candidate data p (p=1, 2, ..., P), the noise level and cost calculation unit 33 first calculates the distance t=X from the sound source j (j=1, 2, ..., M), or more precisely, the position t=X where the sound source j (j=1, 2, ..., M) is installed in the design candidate data p. p、j to the receiving point i (i = 1, 2, ..., N), the sound pressure level L in each frequency band k (k = 63, 125, ..., 8k) k p、i、j is calculated by the following equation (1) (steps S141 to S144).

number

[0039] Next, for each design candidate data p (p=1, 2, ..., P), the noise level and cost calculation unit 33 calculates the energy sum L of the sound pressure level in each frequency band k (k=63, 125, ..., 8k) at each sound receiving point i (i=1, 2, ..., N). k p、i is calculated by the following equation (2) (step S145).

number

[0040] Then, for each design candidate data p (p=1, 2, ..., P), the noise level and cost calculation unit 33 calculates the A-weighted sound pressure level L at each sound receiving point i (i=1, 2, ..., N). p、i (i=1, 2, ..., N) is calculated by the following equation (3) (step S146). A k is the weight of each frequency band of the A-weighting.

number

[0041] Next, the noise level / cost calculation unit 33 calculates the sum of silencer installation costs (total cost) for each of the multiple design candidate data (step S15). The noise level / cost calculation unit 33 calculates the total cost of the silencer candidates to be installed at each sound source, based on the design condition data stored in the database 2 and each of the multiple design candidate data initialized by the initialization unit 32. The total cost of the silencers can be calculated by summing up the installation costs of the types of silencers assigned to each sound source in each design candidate data, based on Fig. 4.

[0042] Fig. 8 shows P pieces of design candidate data obtained by the noise level and cost calculation unit. As shown in Fig. 8, each design candidate data p (p=1, 2, ..., P) contains each sound source j (j=1, 2, ..., M) and the type of silencer (S p、j ), and the correspondence between each of the sound sources j (j=1, 2, ..., M) and the installation position (X p、j ) and the corresponding relationship between the sound pressure level L at each sound receiving point i (i=1, 2, ..., N) calculated by the noise level and cost calculation unit 33. p、i , and the total cost of installing the silencer (C tot、p ) data is associated with the where the value S p、j can take values ​​from 0 to K (K is the number of silencer types). p、j When takes a value from 1 to K, this value indicates the type (identification number) of the silencer assigned to the sound source j in the design candidate data p. p、j When the value of 0 is taken, it indicates that no silencer is assigned to the sound source j in the design candidate data p. Also, for each design candidate data p (p=1, 2, ..., P), the value X p、j j (j=1, 2, . . . , M) has a value from 1 to M that does not overlap with each other.

[0043] Next, the termination determination unit 35 determines whether the processing should be terminated (step S17). The termination determination by the termination determination unit 35 will be described in detail later, but a condition that the number of times step S16, which will be described next, has been repeatedly executed is equal to or greater than the number of design iterations ITER (n≧ITER) input by the parameter input unit 31 is set as part of the determination conditions. Therefore, when the termination determination is executed for the first time by the termination determination unit 35, since step S16 has not yet been executed even once, it is not determined that the processing should be terminated (No in step S17), and the processing transitions to step S16.

[0044] Next, the design candidate data update unit 34 updates the design candidate data (step S16). Specifically, the design candidate data update unit 34 updates the correspondence between the sound source, the installation position, and the type of silencer for each design candidate data. FIG. 9 is a flowchart showing the flow of processing when the design candidate data updating unit updates the design candidate data. The design candidate data update unit 34 regards the correspondence between each sound source in the design candidate data and the installation position and type of muffler assigned to each sound source as the chromosomes of a living organism, and sequentially executes three types of processes: a design candidate data selection process (step S161), a crossover process (step S162), and a mutation process (step S164).

[0045] In the selection process of step S161, the design candidate data update unit 34 evaluates each of the multiple design candidate data and calculates an evaluation value using an objective function that, when a sound source is installed at a position assigned to that sound source in the design candidate data and a silencer of a type assigned to that sound source in the design candidate data is installed at that sound source, the sound pressure level at each sound receiving point is smaller than the regulation value (noise threshold) at that sound receiving point and that takes a larger value as the total installation cost decreases.

[0046] FIG. 10 is a flowchart showing the flow of the selection process executed by the design candidate data update unit. As shown in FIG. 10, in order for the design candidate data update unit 34 to perform the selection process, first, for each of the P design candidate data, the objective function f defined by the following equation (4) m (m = 1, 2,..., P) is obtained (steps S1611, S1612). [Equation] Here, Q m is the number of sound reception points that satisfy the regulation value (noise threshold) in the design candidate data m (m = 1, 2,..., P). C max is the maximum value of the installation cost among all (K types) of mufflers. C tot、m is the total installation cost of the muffler in the design candidate data m (C in FIG. 8 tot、p ). The term MC max represents the total cost when the muffler with the highest installation cost is installed for all M pieces of equipment. Thus, the value of MC max - C tot、m becomes larger as the cheaper muffler is assigned. Therefore, the value of the objective function f m becomes larger as the cheaper muffler is assigned. Note that in the above objective function, the value of MC m - C max is added only when the number Q tot、m of sound reception points that satisfy the regulation value is equal to the total number N of sound reception points, and is not added when it is smaller than N. This indicates that satisfying the regulation value at all sound reception points takes precedence over the cost of the muffler. That is, when the regulation value is not satisfied at all sound reception points (Q m < N), the objective function is designed so that the evaluation value (objective function) becomes small even if the cost of the muffler is low.

[0047] Next, the design candidate data update unit 34 obtains the total sum G of the objective functions by the following equation (5) (step S1613). [Equation] Here, the design candidate data updating unit 34 calculates an evaluation value (objective function f m ) divided by the sum of the evaluation values ​​G m The design candidate data update unit 34 calculates the probability value f / G from among the P pieces of design candidate data in accordance with this probability value, and repeats this process P times. More specifically, the design candidate data update unit 34 calculates the probability value f / G of each piece of design candidate data m in the range of values ​​from 0 to G. m The design candidate data updating unit 34 repeats the process of dividing the design candidate data into a plurality of regions according to / G, randomly generating a value between 0 and G, determining which of the divided regions the value belongs to, and selecting the design candidate data corresponding to that region as the design candidate data to be retained P times. In this way, the design candidate data updating unit 34 reselects P pieces of design candidate data from among the P pieces of design candidate data. This corresponds to spinning a roulette R, as shown in Fig. 11, whose selection probability increases in proportion to the magnitude of the objective function, and extracting design candidate data P times from among the P pieces of design candidate data.

[0048] The probability value f m / G is the objective function f m The larger the value of design candidate data m, the larger the value of the objective function is calculated. Therefore, as described above, the P design candidate data newly obtained by selecting from among the P design candidate data according to the probability value has a high objective function value among the design candidate data before selection. In other words, the sound pressure level at each sound receiving point is calculated to be the value that is higher than the regulation value (noise threshold, L in Figure 5) at that sound receiving point. Ti ) and the total installation cost is likely to be smaller. In this way, by setting a high survival probability for design candidate data that is closer to the target, the design candidate data that is considered more appropriate is preferentially selected and left. As described above, the design candidate data update unit 34 reselects a predetermined number of pieces of design candidate data from among the plurality of design candidate data in accordance with the probability values ​​of each of the plurality of design candidate data (steps S1614, S1615).

[0049] Fig. 12 is a flowchart showing the flow of crossover processing executed by the design candidate data update unit. Fig. 13 is an explanatory diagram of an example of crossover processing related to a silencer. Fig. 14 is an explanatory diagram of an example of crossover processing related to an installation position. In the crossover process of step S162, the design candidate data update unit 34 executes the following process.

[0050] The design candidate data update unit 34 crosses the design candidate data i with other design candidate data at a crossover rate CR. This crossover rate CR is a value input by the parameter input unit 31. Specifically, the design candidate data updating unit 34 executes the following process for all design candidate data i (i=1, 2, . . . , P) (step S1621). First, the design candidate data update unit 34 sets a random number r so that 0≦r<1 (step S1622). Next, the design candidate data update unit 34 compares this random number r with the crossover rate CR (step S1623). If the comparison result shows that the random number r is greater than the crossover rate CR (No in step S1623), the design candidate data update unit 34 does not perform crossover processing on the design candidate data i currently being processed.

[0051] If the random number r is smaller than the crossover rate CR (Yes in step S1623), the design candidate data update unit 34 executes the crossover process on the design candidate data i. The design candidate data update unit 34 first randomly determines other design candidate data j to be crossed (step S1624).

[0052] Next, the design candidate data updating unit 34 performs crossover processing on the type of silencer in steps S1624 and S1625. Specifically, the design candidate data update unit 34 randomly determines the intersection point k from integers ranging from 1 to the number M of sound sources (step S1625). Then, as shown in FIG. 13 , the design candidate data updating unit 34 inherits the types of mufflers to be assigned to the 1st to kth sound sources of the design candidate data i from the original design candidate data i so as to be the same, while inheriting and updating the types of mufflers to be assigned to the (k+1)th to Mth sound sources from the design candidate data j that is the object of intersection, thereby generating new design candidate data i (step S1626).

[0053] In this way, in the crossover processing of step S162, the design candidate data update unit 34 updates the correspondence relationship between the sound sources and the types of silencers in one design candidate data by replacing the type of silencer corresponding to a part of the sound sources in one design candidate data (design candidate data i) with the type of silencer corresponding to the part of the sound sources in another design candidate data (design candidate data j).

[0054] Furthermore, the design candidate data update unit 34 performs crossover processing on the installation position in steps S1627 and onwards. Specifically, the design candidate data update unit 34 first randomly determines an integer n from integers ranging from 1 to the number M of installation positions (step S1627). Next, the design candidate data update unit 34 updates n integers V h (h=1, 2, . . . , n) is determined from integers ranging from 1 to the number M of installation positions, such that the values ​​do not overlap (step S1628). In this way, the design candidate data update unit 34 selects one or more installation positions.

[0055] Next, the design candidate data update unit 34 updates the installation position V h For (h=1, 2, . . . , n), the correspondence between the sound source and the installation position in the design candidate data i is inherited (step S1629). Then, for the sound source to which no installation position was assigned in step S1629, the design candidate data update unit 34 updates the selected installation position V among the multiple installation positions so that the same installation position is not assigned to different sound sources. h An installation position other than (h=1, 2, . . . , n) is assigned (step S1630).

[0056] For example, consider the case where n=4 is determined in step S1627, and V1, V2, V3, and V4 are determined to be 5, 3, 2, and 7, respectively. In this case, as shown in FIG. 14, sound sources 7, 1, 8, and 6 correspond to installation positions 5, 3, 2, and 7 in design candidate data i, respectively. Therefore, after the crossover process is performed, the correspondence between sound sources and installation positions for sound sources 1, 6, 7, and 8 in design candidate data i is inherited and maintained. Then, for sound sources 2, 3, 4, and 5 other than sound sources 1, 6, 7, and 8 to which installation positions have not been assigned as a result, installation positions 1, 4, 6, and 8 other than installation positions 5, 3, 2, and 7 are assigned so that the same installation position is not assigned to different sound sources. In FIG. 14, these installation positions 1, 4, 6, and 8 appear in the order of 6, 8, 1, and 4 in the design candidate data j. Therefore, in the design candidate data i after the crossover process, the correspondence between the sound source and the installation position is updated so that this order is maintained.

[0057] In this way, the design candidate data update unit 34 updates the selected installation position V h For (h=1, 2, ..., n), an installation position is assigned to the sound source so as to inherit the correspondence between the sound source and the installation position in one piece of design candidate data (design candidate data i), and for a sound source to which an installation position has not been assigned, an installation position other than the selected installation position is assigned from among the multiple installation positions so that the same installation position is not assigned to different sound sources, thereby updating the correspondence between the sound source and the installation position in one piece of design candidate data (design candidate data i).

[0058] Instead of steps S1629 and S1630, the crossover process regarding the installation position may be performed as follows. FIG. 15 is an explanatory diagram of another example of crossover processing regarding installation positions. First, the design candidate data update unit 34 updates the selected installation position V h For (h=1, 2, . . . , n), the correspondence between the sound source and the installation position in the design candidate data j is inherited. Then, for the sound source to which no installation position has been assigned, the design candidate data update unit 34 updates the selected installation position V among the multiple installation positions so that the same installation position is not assigned to a different sound source. h Assign an installation position other than (h=1, 2, ..., n).

[0059] For example, consider the case where n=4 is determined in step S1627, and V1, V2, V3, and V4 are determined to be 1, 4, 6, and 8, respectively. In this case, as shown in FIG. 15 , sound sources 5, 7, 1, and 2 correspond to installation positions 1, 4, 6, and 8 in design candidate data j, respectively. Therefore, after the crossover process is performed, the correspondence between sound sources and installation positions for sound sources 1, 2, 5, and 7 in design candidate data j is inherited and maintained in design candidate data i. Then, for sound sources 3, 4, 6, and 8 other than sound sources 1, 2, 5, and 7 to which installation positions have not been assigned as a result, installation positions 2, 3, 5, and 7 other than installation positions 1, 4, 6, and 8 are assigned so that the same installation position is not assigned to different sound sources. In FIG. 15, these installation positions 2, 3, 5, and 7 appear in the order of 3, 7, 5, and 2 in the design candidate data i. Therefore, in the design candidate data i after the crossover process, the correspondence between the sound source and the installation position is updated so that this order is maintained.

[0060] In this way, the design candidate data update unit 34 updates the selected installation position V hFor (h=1, 2, ..., n), an installation position may be assigned to the sound source so that the correspondence between the sound source and the installation position in other design candidate data (design candidate data j) is inherited, and for a sound source to which an installation position has not been assigned, an installation position other than the selected installation position among the multiple installation positions may be assigned so that the same installation position is not assigned to different sound sources, thereby performing crossover processing to update the correspondence between the sound source and the installation position in one design candidate data (design candidate data i).

[0061] As described above, in the crossover process, two pieces of design candidate data i and j are crossed with a certain probability CR to generate new design candidate data.

[0062] FIG. 16 is a flowchart showing the flow of the mutation process executed by the design candidate data update unit. In the mutation process of step S164, the design candidate data update unit 34 executes a silencer type mutation process (steps S1642 to S1645 in FIG. 16) in which the type of silencer corresponding to some sound sources in the design candidate data is randomly replaced with another type of silencer. In addition, in the mutation process of step S164, the design candidate data update unit 34 executes installation position mutation process (steps S1646 to S1649 in FIG. 16) to swap the corresponding installation positions of the first and second sound sources randomly selected in the design candidate data. The design candidate data update unit 34 performs mutation processing on the P pieces of design candidate data newly generated by the crossover processing. The design candidate data update unit 34 performs mutation at a mutation rate MR on the type of silencer assigned to each sound source and the installation position of the sound source in each piece of design candidate data. This mutation rate MR is a value input by the parameter input unit 31.

[0063] The design candidate data update unit 34 executes the following process for all design candidate data i (i=1, 2, . . . , P) (step S1641). First, the design candidate data update unit 34 executes a silencer type mutation process. Specifically, the design candidate data update unit 34 first sets a random number r for each sound source k (k=1, 2, ..., M) of the design candidate data i (step S1642) so that 0≦r<1 (step S1643). Next, the design candidate data update unit 34 compares this random number r with the mutation rate MR (step S1644). If the comparison result shows that the random number r is greater than the mutation rate MR (No in step S1644), the design candidate data update unit 34 does not perform mutation processing on the type of silencer for the sound source k of the design candidate data i currently being processed.

[0064] If the random number r is smaller than the mutation rate MR (Yes in step S1644), the design candidate data update unit 34 executes mutation processing on the sound source k of the design candidate data i. Specifically, the design candidate data update unit 34 randomly determines a value from integers ranging from 0 to K, which is the number of types of silencers, and sets this as a new type of silencer to be assigned to the sound source k (step S1645).

[0065] Next, the design candidate data update unit 34 executes installation position mutation processing. Specifically, the design candidate data updating unit 34 first sets a random number r so that 0≦r<1 (step S1646). Next, the design candidate data update unit 34 compares this random number r with the mutation rate MR (step S1647). If the comparison result shows that the random number r is greater than the mutation rate MR (No in step S1647), the design candidate data update unit 34 does not perform mutation processing on the installation position.

[0066] If the random number r is smaller than the mutation rate MR (Yes in step S1647), the design candidate data update unit 34 randomly determines the integers n1 and n2 from integers ranging from 1 to the number M of sound sources (step S1648). Then, the design candidate data update unit 34 exchanges the corresponding installation positions of the first sound source n1 and the second sound source n2 selected as described above with each other (step S1649). In this way, in the mutation process, both the silencer type mutation process and the installation position mutation process are executed with a certain probability MR.

[0067] In this way, by executing the selection process, crossover process, and mutation process in step S16, the contents of the P design candidate data, more specifically, the correspondence between the sound source, the installation position where the sound source is installed, and the type of silencer to be assigned to the sound source in each design candidate data, are updated compared to before executing step S16. Therefore, in the updated new design candidate data, the sound pressure level at the sound receiving point and the total cost of installing the silencers (total cost) should be different from the design candidate data before the update. Therefore, the noise level / cost calculation unit 33 recalculates the sound pressure level at the sound receiving point and the sum of the silencer installation costs (total cost) for each of the updated P design candidate data (steps S14, S15).

[0068] Thereafter, the termination determination unit 35 determines whether or not the update process of the design candidate data in the design candidate data update unit 34 satisfies a preset termination condition (step S17). Specifically, the termination determination unit 35 determines whether the sound pressure level at each sound receiving point is equal to or greater than the noise threshold value (regulation value, L in FIG. 5 ) of the sound receiving point in at least one of the design candidate data updated by the design candidate data update unit 34 in step S16. Ti ), the design candidate data is registered as the final candidate data. Then, it is determined whether the number of iterations for updating the plurality of design candidate data in the design candidate data update unit 34 (i.e., the number of iterations for executing step S16) has reached a predetermined number, i.e., the number of design iterations ITER input in the parameter input unit 31, and whether this satisfies the termination condition.

[0069] As a result, if it is determined in step S17 that the termination condition is not satisfied (No in step S17), the design candidate data update unit 34 repeats the update process of the design candidate data again (step S16). If it is determined in step S17 that the termination condition is met (Yes in step S17), the design result output unit 36 ​​selects the final candidate data with the smallest total silencer installation cost as the optimum data, and displays the installation positions and silencer types assigned to each sound source, and the total silencer installation cost in the optimum data.

[0070] The above-described noise reduction design support system 1 is a noise reduction design support system 1 that supports noise reduction design for suppressing equipment noise generated from building facilities, and includes: a database 2 in which the propagation loss for each frequency band from each of a plurality of installation positions to be targeted for installing sound sources in the building facilities to each of the sound receiving points, the noise reduction amount and installation cost for each of a plurality of types of silencers for each frequency band, the power level for each sound source for each frequency band, and the noise threshold value of the sound pressure level at each of the sound receiving points are set as design conditions; and an installation plan formulation unit 3 that applies an evolutionary computing method to, for each sound source, select and assign an installation position where the sound source is to be installed from a plurality of installation positions and a silencer to be installed for the sound source from a plurality of types of silencers, based on the propagation loss, the noise reduction amount of the silencer, the installation cost, and the power level, so that the sound pressure levels at all sound receiving points are below the noise threshold value of the sound receiving points and the total installation cost of the silencers is reduced. According to this configuration, based on the propagation loss from each of a plurality of installation positions where a sound source (or equipment that could become a sound source) is to be installed to each of the sound receiving points, the noise reduction amount and installation cost of the silencer, and the power level of the sound source, an evolutionary computing method is applied to select and assign, for each sound source, an installation position where the sound source is to be installed from a plurality of installation positions and a silencer to be installed for the sound source from a plurality of types of silencer, so that the sound pressure levels at all of the sound receiving points will be below the noise threshold of the sound receiving point and the total installation cost of the silencer will be small. In this way, when installing a sound source in a building facility and installing a silencer for the sound source, it is possible to provide a noise reduction design support system 1 that automatically calculates an installation plan for the silencer so that the sound pressure level at the sound receiving point will be below the noise threshold and the installation cost of the silencer will be small.

[0071] The installation plan formulation unit 3 also has a predetermined number of pieces of design candidate data, each of which includes a correspondence between each of the sound sources and the installation positions and types of silencers assigned to each of the sound sources, and is equipped with a design candidate data update unit 34 that repeatedly updates the plurality of design candidate data by changing the correspondence between the plurality of design candidate data through selection processing, crossover processing, and mutation processing in an evolutionary computing method. According to this configuration, a predetermined number of multiple design candidate data are subjected to selection, crossover, and mutation processes in the evolutionary computing method to change the correspondence between each sound source and the installation position and silencer type assigned to each sound source, thereby repeatedly updating the multiple design candidate data. In this way, the installation plan formulation unit 3 treats the multiple design candidate data like chromosomes of a living organism, and by sequentially repeating selection, crossover, and mutation processes, the processing progresses so that design candidate data with more appropriate allocation of installation positions and silencer types to sound sources is preferentially retained. This makes it possible to search for more ideal design candidate data and select an appropriate silencer installation plan.

[0072] The installation plan formulation unit 3 also includes an initialization unit 32 that randomly sets and initializes the installation position and type of silencer for each of the plurality of sound sources for each of the plurality of design candidate data; a noise level and cost calculation unit 33 that calculates the sound pressure levels at all sound receiving points and the total cost of installing the silencers when each of the sound sources is installed at the installation position assigned in the design candidate data and when a silencer of the type assigned in the design candidate data is installed for each of the sound sources; and a design candidate data update unit 34 that updates the plurality of design candidate data. Among these, the system is provided with: a termination determination unit 35 that, if there is any design candidate data for which the sound pressure levels at all sound receiving points are below the noise threshold value of that sound receiving point, registers that design candidate data as final candidate data, and terminates the processing of the design candidate data update unit 34 when the number of repetitions in the design candidate data update unit 34 reaches a predetermined number; and a design result output unit 36 ​​that selects, from the final candidate data, the data with the smallest total cost of installing silencers as optimal data, and displays the installation positions and types of silencers assigned to each sound source in this optimal data, as well as the total cost of installing silencers. With this configuration, if any of the updated design candidate data has sound pressure levels at all sound receiving points that are below the noise thresholds of the sound receiving points, that design candidate data is registered as final candidate data. Furthermore, when the number of iterations in the design candidate data updating unit 34 reaches a predetermined number, the processing of the design candidate data updating unit 34 is terminated. Then, from among the final candidate data, the data with the lowest total silencer installation cost is selected as the optimal data, and the installation positions and silencer types assigned to each sound source, as well as the total silencer installation cost, in this optimal data are displayed. In this way, it is possible to select an appropriate silencer installation plan in which sound pressure levels at all sound receiving points are below the noise thresholds of the sound receiving points and the total silencer installation cost is lowest.

[0073] Furthermore, in the crossover processing, the design candidate data updating unit 34 updates the correspondence between the sound sources and the types of mufflers in one design candidate data by replacing the type of muffler corresponding to a part of the sound sources in one design candidate data with the type of muffler corresponding to the part of the sound sources in another design candidate data, and also selects one or more installation positions, and assigns an installation position to the sound source so that the selected installation position inherits the correspondence between the sound source and the installation position in either one of the one design candidate data or the other design candidate data, and assigns an installation position other than the selected installation position to the sound source to which no installation position has been assigned, from among the multiple installation positions, so that the same installation position is not assigned to different sound sources, thereby updating the correspondence between the sound sources and the installation positions in one design candidate data. With regard to the mufflers, as described above, by replacing the type of muffler corresponding to a part of the sound source in one design candidate data with the type of muffler corresponding to the part of the sound source in another design candidate data, the correspondence between the sound source and the type of muffler in one design candidate data is updated, and the crossover process in the evolutionary computing method can be appropriately realized. In the above-described processing, as a result of the crossover processing, there is a possibility that the same type of silencer is selected and assigned to different sound sources. Since it is possible to prepare multiple silencers for each type, it is acceptable for the same type of silencer to be selected and assigned to multiple different sound sources. However, with regard to the installation location, it is physically impossible to install multiple sound sources, i.e., multiple pieces of equipment, at one installation location at the same time, so it is not permitted for the same installation location to be selected multiple times for different sound sources. In contrast, with regard to installation positions, in the above configuration, one or more installation positions are selected, and an installation position is assigned to a sound source so that the selected installation positions inherit the correspondence between the sound source and the installation position in either one of the design candidate data or the other design candidate data. Then, for sound sources to which no installation position has been assigned, an installation position other than the selected installation position is assigned from among the multiple installation positions so that the same installation position is not assigned to different sound sources, thereby updating the correspondence between the sound source and the installation position in the one design candidate data. This makes it possible to appropriately realize crossover processing in the evolutionary computing method while preventing the same installation position from being assigned to different sound sources in duplicate.

[0074] In addition, in the mutation process, the design candidate data update unit 34 executes a silencer type mutation process in which the type of silencer corresponding to some sound sources in the design candidate data is randomly replaced with another type of silencer, and an installation position mutation process in which the corresponding installation positions of one and two randomly selected sound sources in the design candidate data are swapped with each other. With regard to the mufflers, as described above, by randomly replacing the type of muffler corresponding to some sound sources in the design candidate data with other muffler types, it is possible to appropriately realize the mutation process in the evolutionary computing method. In the above-described process, as a result of the mutation process, there is a possibility that the same type of silencer is selected and assigned to different sound sources. Since it is possible to prepare multiple silencers for each type, it is acceptable for the same type of silencer to be selected and assigned to multiple different sound sources. However, with regard to the installation location, it is physically impossible to simultaneously install multiple sound sources, i.e., multiple pieces of equipment, at one installation location, so it is not permitted for the same installation location to be selected multiple times for different sound sources. In contrast, with regard to the installation positions, in the above configuration, the corresponding installation positions of the first and second sound sources randomly selected in the design candidate data are swapped with each other. In this process, since the installation positions of the two sound sources are simply swapped, if the same installation position is not assigned to different sound sources in the original design candidate data, the same installation position will not be assigned to different sound sources even after the above process. As a result, with regard to the installation positions, it is possible to appropriately realize the mutation process in the evolutionary computing method while preventing the same installation position from being assigned to different sound sources more than once.

[0075] (Modification of the embodiment) The noise reduction design support system of the present invention is not limited to the above-described embodiment explained with reference to the drawings, and various modifications are possible within the technical scope. For example, although the above explanation has been given using an example of allocating silencers to deal with equipment noise, this device can also be used to appropriately allocate vibration-damping materials to be attached to equipment when targeting equipment vibration. In this case, by replacing "sound" with "vibration" in the description of the above embodiment, a similar description to the above embodiment is possible. More specifically, by replacing "sound absorbing design" with "vibration isolation design," "noise and sound pressure" with "vibration," "sound source" with "vibration source," "sound receiving point" with "vibration receiving point," and "muffler" with "vibration isolation material," a similar description to the above embodiment is possible.

[0076] In other words, the vibration isolation design support system is a vibration isolation design support system that supports vibration isolation design to suppress equipment vibrations generated from building facilities, and includes: a database in which the propagation loss for each frequency band from each of a plurality of installation positions to which vibration sources within the building facility are to be installed to each of the receiving points, the vibration reduction amount and installation cost for each of a plurality of types of vibration isolation material, the power level for each frequency band of each vibration source, and the vibration threshold value for the vibration level at each of the receiving points are set as design conditions; and an installation plan formulation unit that applies an evolutionary computing method to, for each vibration source, select and assign an installation location at which to install the vibration source from a plurality of installation positions and a vibration isolation material to be installed for the vibration source from a plurality of types of vibration isolation material, based on the propagation loss, the vibration reduction amount of the vibration isolation material, the installation cost, and the power level, so that the vibration levels at all receiving points are below the vibration threshold value for that receiving point and the total installation cost of the vibration isolation material is small. With this configuration, an installation plan for vibration sources and vibration-isolating materials is obtained by applying an evolutionary computing method to select and assign, for each vibration source, an installation location from among multiple installation locations and a vibration-isolating material to be installed for that vibration source from among multiple types of vibration-isolating materials, based on the propagation loss from each of multiple installation locations where vibration sources (or potential equipment) are to be installed to each receiving point, the vibration reduction amount and installation cost of the vibration-isolating material, and the power level of the vibration source, so that the vibration levels at all receiving points are below the vibration threshold for that vibration-isolating point and the total installation cost of the vibration-isolating material is reduced.This makes it possible to provide a vibration-isolation design support system that, when installing vibration sources in a building facility and installing vibration-isolation materials for the vibration sources, automatically calculates an installation plan for vibration-isolation material so that the vibration levels at the receiving points are below the vibration threshold and the installation cost of the vibration-isolation material is reduced.

[0077] The installation plan formulation unit also has a predetermined number of multiple pieces of design candidate data, each of which includes a correspondence between each of the vibration sources and the installation position and type of vibration-damping material assigned to each of the vibration sources, and is equipped with a design candidate data update unit that repeatedly updates the multiple design candidate data by changing the correspondence between the multiple design candidate data through selection processing, crossover processing, and mutation processing in an evolutionary computing method. According to this configuration, a predetermined number of design candidate data are repeatedly updated by changing the correspondence between each vibration source and the installation position and type of vibration-damping material assigned to each vibration source through selection, crossover, and mutation processes in an evolutionary computing method. In this way, the installation plan formulation unit treats the design candidate data like chromosomes in a living organism, and sequentially repeats selection, crossover, and mutation processes to prioritize and retain design candidate data with more appropriate assignments of installation positions and types of vibration-damping materials to vibration sources. This allows for the search for more ideal design candidate data and the selection of an appropriate vibration-damping material installation plan.

[0078] The installation plan formulation unit also includes: an initialization unit that randomly sets and initializes an installation position and a type of vibration-damping material for each of the plurality of design candidate data; a vibration level / cost calculation unit that calculates, for each of the plurality of design candidate data, the vibration levels at all receiving points and the total installation costs of the vibration-damping materials when each of the vibration sources is installed at the installation position assigned in the design candidate data and when each of the vibration sources is installed with the type of vibration-damping material assigned in the design candidate data; a termination determination unit that, if any of the plurality of design candidate data updated by the design candidate data update unit has vibration levels at all receiving points that are lower than the vibration threshold values ​​of the corresponding receiving points, registers the design candidate data as final candidate data and terminates the processing of the design candidate data update unit when the number of iterations in the design candidate data update unit reaches a predetermined number; and a design result output unit that selects, from the final candidate data, the data with the smallest total installation costs of the vibration-damping materials as optimal data and displays the installation positions and types of vibration-damping materials assigned to each of the vibration sources and the total installation costs of the vibration-damping materials in this optimal data. According to this configuration, if any of the updated design candidate data sets has vibration levels at all receiving points that are below the vibration thresholds for those receiving points, that design candidate data set is registered as final candidate data. Furthermore, if the number of iterations in the design candidate data update unit reaches a predetermined number, the processing of the design candidate data update unit is terminated. Then, among the final candidate data sets, the data set with the lowest total vibration-damping material installation cost is selected as the optimal data set, and the installation locations and types of vibration-damping materials assigned to each vibration source, as well as the total vibration-damping material installation cost, in this optimal data set are displayed. In this way, an appropriate vibration-damping material installation plan can be selected in which the vibration levels at all receiving points are below the vibration thresholds for those receiving points and the total vibration-damping material installation cost is lowest.

[0079] In addition, the configurations given in the above embodiments can be selected or changed as appropriate without departing from the spirit of the present invention. In the above embodiment, a silencer is installed to reduce the sound pressure level of equipment noise to below the noise threshold, but the noise reduction design support system is not limited to a silencer and may be any one of soundproofing material, sound-absorbing material, sound-insulating material, vibration-proofing material, and vibration-damping material, or a combination of these. In addition, in the above embodiment, the number M of installation locations where sound sources (equipment that emits sound sources) are to be installed is described as being the same value as the number M of sound sources, but instead, the number of installation locations may be greater than the number of sound sources. [Explanation of symbols]

[0080] 1 Noise reduction design support system 33 Noise level and cost calculation section 2 Database 34 Design candidate data update section 3. Installation Planning Department 35. Completion Assessment Department 32 Initialization section 36 Design result output section

Claims

1. A noise reduction design support system that supports noise reduction design for suppressing equipment noise generated from building facilities, a database in which the propagation loss for each frequency band from each of a plurality of target installation positions for installing sound sources within a building facility to each of the sound receiving points, the noise reduction amount and installation cost for each of a plurality of types of silencers for each frequency band, the power level for each of the sound sources for each frequency band, and the noise threshold value of the sound pressure level at each of the sound receiving points are set as design conditions; an installation plan formulation unit that formulates installation plans for the sound sources and the silencers by applying an evolutionary computing method to, for each sound source, select and assign an installation position at which the sound source is to be installed from a plurality of installation positions and a silencer to be installed for the sound source from a plurality of types of silencers, so that sound pressure levels at all of the sound receiving points are made lower than the noise thresholds at the sound receiving points and the total installation cost of the silencers is reduced, based on the propagation loss, the noise reduction amount, the installation cost, and the power level; A noise reduction design support system comprising:

2. the installation plan formulation unit has a predetermined number of pieces of design candidate data; each of the plurality of design candidate data includes a correspondence relationship between each of the sound sources and the installation positions and types of the silencers assigned to each of the sound sources; a design candidate data update unit that repeatedly updates the plurality of design candidate data by changing the correspondence relationship through selection processing, crossover processing, and mutation processing in the evolutionary computing method for the plurality of design candidate data; 2. The noise reduction design support system according to claim 1.

3. The installation plan development department an initialization unit that randomly sets and initializes the installation position and the type of the silencer for each of the sound sources for each of the plurality of design candidate data; a noise level / cost calculation unit that calculates, for each of the plurality of design candidate data, the sound pressure levels at all the sound receiving points and a total of the installation costs of the silencers when each of the sound sources is installed at the installation positions assigned in the design candidate data and when each of the sound sources is installed with a silencer of the type assigned in the design candidate data; a termination determination unit that, if there is any design candidate data among the plurality of design candidate data updated by the design candidate data update unit in which the sound pressure levels at all the sound receiving points are lower than the noise threshold values ​​of the sound receiving points, registers the design candidate data as final candidate data, and terminates the processing of the design candidate data update unit when the number of iterations in the design candidate data update unit reaches a predetermined number; a design result output unit that selects, from the final candidate data, one that has the smallest total installation cost of the silencers as optimal data, and displays, in the optimal data, the installation positions and types of the silencers assigned to each of the sound sources, and the total installation cost of the silencers; 3. The noise reduction design support system according to claim 2, further comprising:

4. In the crossover process, the design candidate data update unit By replacing the type of the muffler corresponding to a part of the sound source in one of the design candidate data with the type of the muffler corresponding to the part of the sound source in another of the design candidate data, the correspondence relationship between the sound source and the type of the muffler in the one of the design candidate data is updated; and One or more installation positions are selected, and the installation positions are assigned to the sound sources so that the selected installation positions inherit the correspondence relationship between the sound sources and the installation positions in either one of the one design candidate data or the other design candidate data, and for the sound sources to which no installation position has been assigned, an installation position other than the selected installation position is assigned to the sound sources so that the same installation position is not assigned to different sound sources, thereby updating the correspondence relationship between the sound sources and the installation positions in the one design candidate data.

4. The noise reduction design support system according to claim 2 or 3.

5. In the mutation process, the design candidate data update unit a silencer type mutation process for randomly replacing the types of silencers corresponding to some of the sound sources in the design candidate data with other types of silencers; an installation position mutation process for exchanging the corresponding installation positions of one randomly selected sound source and a second randomly selected sound source in the design candidate data; 4. The noise reduction design support system according to claim 2, wherein the noise reduction design support system executes the following steps.

6. A vibration isolation design support system that supports vibration isolation design to suppress equipment vibrations generated from building facilities, a database in which the propagation loss for each frequency band from each of a plurality of installation positions where vibration sources are to be installed within a building facility to each of the vibration receiving points, the vibration reduction amount and installation cost for each of a plurality of types of vibration-damping materials for each frequency band, the power level for each of the vibration sources for each frequency band, and the vibration threshold value of the vibration level at each of the vibration receiving points are set as design conditions; an installation plan formulation unit that formulates installation plans for the vibration sources and the vibration-damping materials by applying an evolutionary computing method to, for each vibration source, select and assign an installation position for the vibration source from a plurality of installation positions and an vibration-damping material to be installed for the vibration source from a plurality of types of vibration-damping materials, so that the vibration levels at all of the vibration-receiving points are below the vibration threshold value for the vibration-receiving points and the total installation cost of the vibration-damping materials is reduced, based on the propagation loss, the vibration reduction amount, the installation cost, and the power level; A vibration-proof design support system comprising:

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