50results about How to "Reasonable weight distribution" patented technology

The invention provides a method and a device for evaluating fighting capability of an air defense and antimissile system. The method comprises the following steps: establishing a fighting capability evaluation model based on an evaluation index corresponding to a fighting activity, obtaining quantitative indicator data of a to-be-evaluated air defense and antimissile system based on the model, andbuilding a corresponding capability requirement satisfaction degree evaluation matrix; based on the evaluation index, using an interpretative structural modeling method to construct an index networkhierarchical model corresponding to the to-be-evaluated air defense and antimissile system; based on the index network hierarchical model, using a network hierarchical analytic method to calculate theweight corresponding to each evaluation index; and evaluating the comprehensive fighting capability of the to-be-evaluated air defense and antimissile system based on the weight corresponding to eachevaluation index and the capability requirement satisfaction degree evaluation matrix corresponding to the quantitative index data. The method and the device for evaluating fighting capability of theair defense and antimissile system in the invention can deeply analyze and directly reflect the internal logical relationship of the air defense and antimissile indicator system, so that the weight distribution between the indicators is more reasonable, thereby effectively improving the comprehensiveness, effectiveness and credibility of the evaluation results.

The invention provides a flying wing layout aircraft which comprises an aircraft body (1), aircraft wings (2), ailerons, an elevator (5) and double vertical fins (4), wherein the aircraft body (1) and the aircraft wings (2) are integrated; the ailerons (3) are positioned on the outer sections of the aircraft wings (2), and are used for rolling control in level flight; the elevator (5) is positioned at the rearmost part of the aircraft body (1), and is used for pitching control in level flight; and the dual vertical fins (4) are positioned at the rear part of the aircraft body (1), and are used for enhancing the flight direction safety in level flight. The flying wing layout aircraft provided by the invention has the advantages that the aircraft body integration technique inherits the excellent pneumatic property of the flying wings, and larger internal space is provided; the weight distribution is more reasonable, and the structure is lighter, so that the load and the voyage are increased; front air screws which are arranged in an engine and tilt and rear air screws which are fixed and can be accommodated in the vertical fins achieve the capability of vertical / short take-off and landing, and the interference to the whole pneumatic appearance of the aircraft is lowered greatly; and the connection shaft design among engines greatly improves the reliability of a dynamic system, avoids the dangerous situation of invalidity after taking off, and guarantees the flight safety in vertical / short take-off and landing.

The invention provides a frame level feature aggregation method for video target detection, and relates to the technical field of computer vision. The invention provides a frame-level feature aggregation method for video target detection. The method comprises the following steps: firstly, extracting deep features from a single-frame image through a feature network; extracting an inter-frame optical flow by using an optical flow network FlowNet; aligning the frame-level features of the adjacent frames to the current frame based on the optical flow to realize frame-level feature propagation; finally, calculating the scaling cosine similarity weight through the mapping network and the weight scaling network, and using the scaling cosine similarity weight to aggregate the multi-frame featuresto generate the aggregated features. According to the frame-level feature aggregation method for video target detection provided by the invention, the weight distribution is more reasonable, and the aggregated features are input into the video target detection network, so that video detection in complex scenes such as motion blur, low pixels, lens zooming and shielding can have a better detectioneffect and robustness.

The invention discloses an attribution method and device of information putting effects. The method comprises steps of after counting information conversion frequency and information reaching frequency brought by each channel combination consisting of a single channel combination put by an information putting party within a set period, determining the information conversion rate of each channel combination according to the information conversion frequency and the information reaching frequency brought by each channel combination; determining the weight of each single channel in each channel combination according to the information conversion rate of each channel combination; and based on the weight of each single channel in each channel combination, determining the information conversion frequency brought by each signal channel. Compared with the current attribution method of information putting effects, the provided method is characterized in that effects caused by different channel cooperation are fully considered, so it can be ensured that the distribution weight corresponding to each signal channel is quite precise and proper, and problems of improper and inaccurate attributionin the current attribution method of information putting effects are solved.

The invention discloses a fuzzy mathematics-based gas pipeline third-party damage risk assessment method, which can realize quantitative assessment of gas pipeline third-party damage risk. According to the technical scheme, various possible conditions of a gas pipeline third-party damage accident are systematically analyzed by adopting an analytical hierarchy process and an MMESE system theory for characteristics of diversity, complexity, uncertainty and the like of the gas pipeline third-party damage accident, a three-level hierarchical structure model is built, and a triangular fuzzy number is introduced according to a fuzziness characteristic, so that a relative importance degree among factors is quantitatively represented, the limitation of the analytical hierarchy process is overcome, human subjective influence in a conventional assessment method is reduced, and weight allocation is more accurate, objective and reasonable. The method has the advantages that the limitation of the analytical hierarchy process is overcome, and the subjective influence of the human factors in the conventional assessment method is reduced; and the weight allocation is reasonable, and an assessment result is objective and accurate.

The invention discloses a method for estimating and calculating the strength of a power transmission pole tower material on the basis of a rough-fuzzy set. The method comprises the following steps of performing reduction on an index set by using a rough set theory; determining evaluation index weight by a method that subjective weight and objective weight are combined; according to an established evaluation order set, comprehensively evaluating and calculating the actual strength of the tower material by using a fuzzy mathematical method. The typical uncertain problem that the factorial validity affecting the strength of the tower material is not clear in an evolutionary process can be solved. The method can provide an important scientific criterion to the safety evaluation of an iron tower structure.

The invention discloses a segmented tree disparity map acquisition method based on improved matching cost. The method comprises the following steps: carrying out pixel point acquisition on a left image and a right image; establishing a matrix; performing cost calculation; converting the undirected connected graph; converting the minimum spanning tree; calculating the weight between adjacent pixelpoints; cost aggregation; acquiring left and right disparity maps wherein left and right pixels are consistent; introducing depth information and color information; performing cost aggregation again;obtaining a final disparity map. For the defect that ambiguity matching is easily generated in a weak texture region, color and gradient multi-dimensional information components are introduced, so that the weight distribution of a window is more reasonable, and the cost amount of pixel points in the weak texture region is enhanced; a novel grouping strategy is provided, and pixel points conformingto parallax consistency are divided to the same spanning tree; and a more accurate matching result can be generated while the time efficiency is kept.

The invention discloses a method for estimating and calculating the strength of a power transmission pole tower material on the basis of a rough-fuzzy set. The method comprises the following steps of performing reduction on an index set by using a rough set theory; determining evaluation index weight by a method that subjective weight and objective weight are combined; according to an established evaluation order set, comprehensively evaluating and calculating the actual strength of the tower material by using a fuzzy mathematical method. The typical uncertain problem that the factorial validity affecting the strength of the tower material is not clear in an evolutionary process can be solved. The method can provide an important scientific criterion to the safety evaluation of an iron tower structure.

The invention discloses a method for estimating and calculating the strength of a power transmission pole tower material on the basis of a rough-fuzzy set. The method comprises the following steps of performing reduction on an index set by using a rough set theory; determining evaluation index weight by a method that subjective weight and objective weight are combined; according to an established evaluation order set, comprehensively evaluating and calculating the actual strength of the tower material by using a fuzzy mathematical method. The typical uncertain problem that the factorial validity affecting the strength of the tower material is not clear in an evolutionary process can be solved. The method can provide an important scientific criterion to the safety evaluation of an iron tower structure.

The invention provides an asphalt pavement comprehensive performance evaluation method based on an unascertained measurement theory, and relates to the technical field of road engineering, and the method comprises the following steps: establishing a performance index system of an asphalt pavement, and determining a to-be-evaluated road section; determining a grading standard matrix based on the performance index data; establishing a measurement function parameter optimization framework, establishing a measurement function set, and optimizing parameters of measurement functions; calculating a single-index measurement value of the to-be-evaluated road section in the evaluation grade space based on the measurement function to obtain a single-index measurement matrix; calculating a combined weight vector of each index; calculating a comprehensive measure evaluation matrix of the to-be-evaluated road section by combining the single-index measure matrix and the combined weight vector; and determining a final evaluation grade of the to-be-evaluated road section based on a confidence identification criterion. According to the method, comprehensive evaluation of the surface layer and internal performance of the asphalt pavement can be realized, and the technical defects of insufficient consideration of internal diseases, single evaluation index, unreasonable weight distribution and the like in a traditional evaluation method are overcome.

The invention relates to a novel badminton. The badminton contains an independent rotating component (15) which is not adhered to a badminton skirt (12), and the rotating component (15) has various kinds of structures, wherein, optimally the rotating component comprises a plurality of rotating wind resistance fins (152) or rotating wind resistance wall surfaces (153); and optimally the rotating wind resistance fins (152) or the rotating wind resistance wall surfaces (153) and the cross section of the badminton form an inclined angle (B) along an axis direction. The independent rotating component (15) has higher efficiency so as to more conveniently control weight, center-of-gravity position and weight distribution of the badminton; and the rotating component (15) and the badminton skirt (12) of the badminton can be respectively made into an independently molded fitting so as to enhance overall performance and facilitate production. The invention further relates to a badminton body containing the rotating component (15).

The invention discloses a method for calculating a ship weight longitudinally distributed load density. By adopting the method, the situation that partial weight losses or distortion of equipment at aship bow / stern can be avoided, so that weight distributed load density is more reasonable and accurate. According to the method for calculating the ship weight longitudinally distributed load density, the ship bow and the stern can serve as complete standard theoretical station distances correspondingly, 20 standard theoretical station distances in a traditional method are expanded to be 22 standard theoretical station distances, and then weight of each equipment or goods on a ship is equivalently distributed on the standard theoretical station distances in theoretical station distance ranges where the equipment or the goods are located according to a static force equivalence principle; and the weight distributed in the ship bow standard theoretical station distance and the stern standard theoretical station distance is converted into two standard theoretical station distances adjacent to the ship bow standard theoretical station distance and the stern standard theoretical station distance, and finally weight distribution of the 20 standard theoretical station distances of a hull, namely, the ship weight longitudinally distributed load density, is obtained. Partial weight lossesor distortion of the equipment at the ship bow / stern is avoided, and weight distributed load density is more accurate.

The invention relates to a short-term load prediction technology of a power system, and aims to provide a federated learning load prediction method based on dynamic weighted aggregation. According to the method, an edge computing device adopts local data to carry out neural network training, network parameter change vectors are obtained and uploaded to a cloud server to carry out pairwise similarity calculation to generate a similarity matrix, and a consistency vector between local models in the current round of training is calculated. And then weighting network parameter changes of different local models based on the consistency between the accuracy of each round of local model for the server verification set and the local models to realize a local model cleaning effect, issuing the updated global model to the edge computing device by the cloud server, and repeating the above steps to realize the cleaning effect of the local models. And the server reaches the preset training round number. The problem that a dirty model possibly trained by a local model and data isomerism in federal learning cannot be effectively avoided in the prior art is solved, and convergence of global model training is accelerated.

The invention discloses a gear grinding machine comprising a machine body, a second rotating shaft box body, a sliding table and a cooling oil tank; the side wall of the machine body is provided withan X-axis guide rail; the second rotating shaft box body is slidably installed on the X-axis guide rail, and internally provided with a rotating shaft B; the tail end of the rotating shaft B is provided with a first rotating shaft box body which is internally provided with a workpiece spindle A, and the end of the workpiece spindle A is provided with a workpiece; the sliding table is movably installed on the machine body, and located above the second rotating shaft box body; the sliding table is provided with a third rotating shaft box body which is internally provided with a grinding wheel spindle C of which the lower end is provided with a grinding wheel; and the cooling oil tank is arranged below the first rotating shaft box body in the X-axis direction. Compared with a traditional structure, the gear grinding machine has the advantages that the three movable shafts are not stacked, and accordingly the removal and installation are simple and convenient; not only can the production efficiency be improved, but also the maintenance is convenient; the weight distribution is more reasonable, and the situation that the gear grinding machine is not top-heavy is avoided, so that the counterweight of the machine body can be further reduced; and the size of the machine is reduced.

The invention provides a flying wing layout aircraft which comprises an aircraft body (1), aircraft wings (2), ailerons, an elevator (5) and double vertical fins (4), wherein the aircraft body (1) and the aircraft wings (2) are integrated; the ailerons (3) are positioned on the outer sections of the aircraft wings (2), and are used for rolling control in level flight; the elevator (5) is positioned at the rearmost part of the aircraft body (1), and is used for pitching control in level flight; and the dual vertical fins (4) are positioned at the rear part of the aircraft body (1), and are used for enhancing the flight direction safety in level flight. The flying wing layout aircraft provided by the invention has the advantages that the aircraft body integration technique inherits the excellent pneumatic property of the flying wings, and larger internal space is provided; the weight distribution is more reasonable, and the structure is lighter, so that the load and the voyage are increased; front air screws which are arranged in an engine and tilt and rear air screws which are fixed and can be accommodated in the vertical fins achieve the capability of vertical / short take-off and landing, and the interference to the whole pneumatic appearance of the aircraft is lowered greatly; and the connection shaft design among engines greatly improves the reliability of a dynamic system, avoids the dangerous situation of invalidity after taking off, and guarantees the flight safety in vertical / short take-off and landing.

A kind of golf bulb, comprises knock face, ball bottom, ball cover, pipe and bulb latus. The knock face is connected to the other parts by welding material. The ball cover and the bulb latus are connected as one body. The ball bottom is connected to the bulb by welding material. The invention's structure is good to lower the height of the gravity. As the ball bottom is a single spare part, we can change the thickness freely to adjust the bulb's gravity. The throat is formed by the one time tension, so the correlation is good, and the shape is nearer to the design request.

The invention provides a professional learning ability evaluation method based on an interval neutrosophy theory. The method comprises the following steps: determining an evaluation object, an evaluation index, an evaluation expert and a weight thereof; determining index weights: obtaining evaluation values of evaluation experts on the evaluation indexes, and determining weights of the indexes; evaluating a key index: obtaining an aggregated decision matrix of the review expert, setting the key index and calculating the certainty degree, and judging whether the key index is qualified or not according to a certainty degree threshold value; and comprehensive optimization evaluation: carrying out weighted similarity calculation on the objects with qualified key index evaluation, and determining the professional learning ability of the evaluation objects according to weighted similarity sorting. The invention further provides a professional learning ability evaluation system based on the interval neutrosophy theory. According to the method and system, the interval neutrosophy theory is introduced into the professional learning ability evaluation process of the students, so that the accuracy and effectiveness of decision making can be effectively improved; and weight distribution is more reasonable.

The invention relates to a high-voltage line insulator detection and cleaning robot, which includes a three-layer bracket, several clamping mechanisms, a climbing telescopic mechanism, an insulator live detection device, and an insulator cleaning mechanism. The clamping mechanism, the insulator live detection device and the insulator cleaning mechanism are all arranged on the bracket, and the bracket is connected through a climbing telescopic mechanism. The invention can climb along the insulator string and automatically clean and detect the insulators. The invention has compact structure, comprehensive functions, stable crawling, simple stringing operation, can short-circuit up to three insulators, and is suitable for live cleaning and detection of horizontal and suspended insulator strings.

The invention discloses a hydraulic engineering safety evaluation method based on the improved fuzzy analytic hierarchy process, and mainly solves the problem that the evaluation result of an existing water conservancy project safety evaluation method is inaccurate. The method comprises the following steps: (S1) determining a factor set of an evaluation object; (S2) determining an evaluation grade set of the evaluation object; (S3) performing single-factor evaluation on the evaluation object to form a membership matrix; (S4) determining a factor weight vector of the evaluation object to obtain a judgment matrix, and carrying out numeralization or normalization on the evaluation grade set; (S5) obtaining a comprehensive evaluation result vector matrix; and (S6) performing judgment according to a membership degree maximum principle, or solving a membership degree grade by using weighted average to obtain a comprehensive judgment value. According to the method, an improved fuzzy comprehensive evaluation method based on natural index e0 / 4-e8 / 4 scales is adopted, safety evaluation is carried out on the water conservancy project, subjective weights and objective weights of bottom layer evaluation indexes are optimized, the subjective weights are corrected, and weight distribution of the indexes is more reasonable.

An intelligent subway rail welding vehicle comprises a frame (1), a cab (4), a functional room (2), an operation room (5) and a welding machine room (21) are arranged above the frame (1), a power transmission system (6) and a hydraulic oil tank (14) are arranged in the functional room (2), an office area and an operation area are arranged in the operation room (5), a welding machine (19) and a welding machine take-up and pay-off device (20) is arranged in the welding room (21). A front driving bogie (9), a diesel tank (7) and a rear driving bogie (10) are arranged below the frame (1); escalators (13) are arranged on the two sides of the front drive bogie (9); and an overturn door (17) is arranged at the end of the welding machine room (21). The intelligent subway rail welding vehicle can automatically run to a rail welding site to conduct online welding, offline welding and base welding, and if extreme derailment occurs, the vehicle can be rapidly lifted and restored; all operations inthe operation process are designed mechanically and automatically.

The invention relates to the technical field of power generation equipment data monitoring, in particular to a new energy power generation equipment accurate monitoring and operation data analysis method. Comprising the following steps: data acquisition and storage: deploying sensors at key nodes to acquire data; evaluating a running state, extracting key indexes such as equipment efficiency, energy consumption and environmental adaptability, and quantifying a scoring standard; an evaluation function is constructed, an analytic hierarchy process and an entropy weight method are combined to determine a weight, and a normalized weight value and a comprehensive evaluation value are calculated; carrying out anomaly detection and early warning, defining an early warning level based on the comprehensive evaluation value, and carrying out mean shift detection; early warning operation and emergency response are carried out, a feedback mechanism is established, and emergency measures under different early warning levels are formulated. According to the method, the equipment operation state monitoring accuracy, the data evaluation scientificity and the abnormity processing timeliness and effectiveness are improved, and stable operation and efficient power generation of the new energy power generation equipment are guaranteed.

The invention discloses a polishing main machine installing structure with a stable structure. The polishing main machine installing structure comprises a swing beam and at least one polishing main machine installed on the swing beam, wherein the grinding main machine comprises a base, a main shaft, a grinding head and a driving motor, the main shaft is rotationally installed on the supporting frame, the driving motor is fixedly installed on the motor installation base to drive the main shaft to rotate, the grinding head is installed at the lower end of the main shaft, a first installing fitting surface is formed on the outer side wall of the supporting frame below the motor installing base, a first supporting clamping groove is formed in the upper end of the first installing fitting surface, a second installing fitting surface is arranged on the outer side wall of the swing beam, and a second supporting clamping groove is formed in the upper end of the second installing fitting surface. Compared with the prior art, the mode that the base body of the polishing main machine is installed on the side portion of the swing beam is adopted, so that the weight distribution of the whole structure is more reasonable, and meanwhile the polishing main machine can be conveniently installed and uninstalled from the swing beam, the structure of the swing beam is simplified, and the production difficulty and cost of the main beam are reduced.

The utility model discloses a sinking wave station platform capable of adjusting internal weight distribution and reducing underwater overturning, which relates to the technical field of underwater monitoring equipment and comprises a rectangular-ambulatory-plane support frame, a plurality of groups of sliding bearing components are mounted on the rectangular-ambulatory-plane support frame, and a plurality of groups of vertical support rods are mounted at four corners of the top wall of the rectangular-ambulatory-plane support frame. Lateral support plates are obliquely fixed to the top walls of the multiple sets of vertical support rods, transverse support plates are fixed to the top walls of the multiple sets of lateral support plates, first steel plates are fixedly welded to the outer walls of the multiple sets of lateral support plates, and a second steel plate is detachably installed on the outer wall of the lateral support plate on one side. The internal weight can be adjusted by adjusting the position of the sliding bearing assembly, the weight distribution of the platform is reasonable, then the second steel plate and the first steel plate are installed on the lateral support plate, a prismatic table structure is formed, the prismatic table structure is kept horizontal, and the gravity center and the buoyancy center of the prismatic table structure are located on the same vertical line.

The invention belongs to the field of aircraft ditching test, and in particular relates to a floating characteristic test model. In the case of strict weight requirements, the general model has low strength and is easily damaged. The present invention proposes a floating characteristic test model, including a fuselage, wings and empennage, wherein the fuselage is divided into an upper fuselage compartment and a lower fuselage compartment by a fuselage floor, and a lifting device is installed above the middle of the upper fuselage compartment. Adjustment system, the lifting lugs can adjust the position front and rear in the waist hole of the lifting adjustment system; a vent pipe connecting the upper compartment and the lower compartment of the fuselage is arranged on the height of the fuselage floor; the lower compartment of the fuselage has There are seepage holes, and the bottom of the lower fuselage frame has overflow holes connecting adjacent compartments; black and white waterline scales are painted on the outside of the fuselage skin. It can meet the requirements of harsh test conditions.

The invention provides a gas leakage risk monitoring and early warning method considering a multi-accident coupling risk, and relates to the technical field of urban gas pipeline safety monitoring, and the method comprises the following steps: determining a multi-accident risk factor set related to gas leakage, the risk factors are divided into four categories of pipeline body factors, environmental factors, operation and maintenance management factors and multi-accident coupling factors; respectively calculating the subjective weight and the objective weight of each risk factor by adopting a combined weighting method combining an analytic hierarchy process and an entropy weight method to obtain a comprehensive weight; constructing a coupling effect strength model, calculating a coupling coefficient between different types of risk factors, and representing an amplification effect of multi-accident interaction on the gas leakage risk; according to the gas leakage risk monitoring system, the multi-accident coupling factor is introduced into the gas leakage risk monitoring system, the system covers the four risk factors of the pipeline body, the environment, the operation and maintenance management and the multi-accident coupling, and the problems that a traditional method is incomplete in risk coverage and neglects the coupling effect are solved.

The invention provides a verification system in a photoinitiator preparation process and a preparation process thereof, and relates to the technical field of photoinitiator evaluation and verification, the verification system in the photoinitiator preparation process comprises a sample analysis unit, an index acquisition unit, a purity evaluation unit and a standard comparison unit, the sample analysis unit, the index acquisition unit, the purity evaluation unit and the standard comparison unit are connected in sequence. According to the method, the purity of the photoinitiator can be scientifically and objectively evaluated, the evaluation result is compared with the preset evaluation standard, the objectivity and consistency of the verification result are ensured through the standardized comparison mode, whether the photoinitiator meets the preparation requirement or not can be determined through comparison, and the accuracy of the photoinitiator is improved. And a reliable basis is provided for subsequent production and use.

The present application relates to the technical field of soil parameter remote sensing estimation, and particularly relates to a microwave soil equivalent temperature physical estimation method considering thermal sampling depth, comprising: obtaining soil temperature and humidity profile, surface temperature and soil texture data; combining dielectric constant model to calculate attenuation coefficients at different depths; determining thermal sampling depth based on the attenuation coefficients and dividing into multiple discrete layers; calculating average temperature using top and bottom temperatures of each layer according to soil heat conduction characteristics; calculating contribution weight of each layer to equivalent temperature based on attenuation coefficients and thickness of each layer; and obtaining microwave soil equivalent temperature by weighted sum of average temperature and weight of each layer. The present application has clear physical meaning, high estimation precision and is suitable for multiple frequencies, and overcomes the problem of limited precision or unclear physical meaning in the prior art.

The invention discloses a SMOTE+Boosting algorithm based software defect tendency prediction method. The method comprises the steps of for the non-equilibrium problem of software defect data, firstly synthesizing artificial minority class samples by using an SMOTE algorithm and enabling the minority class samples and majority class samples to be balanced in quantity; secondly, calculating a penalty factor of each artificial minority class sample according to density information of original sample distribution to adjust a weight of the artificial sample so as to enable a basic classifier to distinguish the learning of an original sample and the artificial minority class sample and put more emphasis on the learning of the original sample and the artificial sample with relatively high credibility; continuing to use an original loss function for the original sample, adding a penalty factor for the loss function of the artificial minority class sample to penalize the artificial sample with low credibility, and determining a new loss function; and finally, forming a new Boosting algorithm. According to the method, the classification precision of a minority class and a majority class is improved and the problem of low classification precision of a classification model to the minority class caused by data non-equilibrium in the field of prediction and classification is solved to a certain extent.

The invention relates to the technical field of vehicle power supplies, and provides a method and system for determining the charging frequency of a vehicle door lock power supply and a vehicle terminal. The first relative weight is determined according to the relative importance between the power supply function data, and the probability that the door lock power supply is in the abnormal state is calculated according to the power supply function data and the first relative weight, so that the charging frequency of the door lock power supply is set according to the positive correlation and the obtained power supply evaluation result; the probability that the door lock power supply is in an abnormal state is calculated according to the power supply function data, then the charging frequency of the door lock power supply is set according to a power supply evaluation result obtained through evaluation, dynamic adjustment of the charging frequency is achieved, and the relative weight is determined according to the relative importance between the power supply function data. And the incidence relation between the power supply function data is introduced, so that the weight distribution is more reasonable, and the reliability of the standby power supply is improved by setting the charging frequency meeting the service requirements.