309results about How to "Get rid of restrictions" patented technology

The embodiment of the invention discloses a storage virtualization device, a data storage method and a system. The storage virtualization device comprises a logic storage unit module, a resource block module, a mapping module and a data write-in module, wherein the logic storage unit module is used for carrying out RIAD(Redundant Array of Inexpensive Disks) partitioning to at least two solid-state memories so as to form at least one logic memory unit; the resource block module is used for striping treatment to the logic memory unit so as to form storage resource blocks respectively corresponding to the strips of the logic memory unit; the mapping module is used for receiving write request messages sent out by a host machine, obtaining logic blocks for writing to-be-written date according to logic addresses carried in the write request messages, acquiring idle storage resource blocks, calculating the numbers of physical blocks of the acquired idle storage resource blocks, and building a mapping relationship between the logical blocks and the physical blocks; and the data write-in module is used for writing to-be written date into corresponding storage spaces of the physical blocks according to the mapping relationship. The storage virtualization device, the data storage method and the system can improve the use ratio of physical storage space.

The invention discloses a compensation method for error calibration of an MEMS gyroscope in an MIMU. The method uses a novel error model of the MEMS gyroscope. The method can complete calibration for non-orthogonal errors and temperature errors of the MEMS gyroscope in cases of existing devices: a rotary table with a thermostat and a single shaft being capable of rotating in 360 DEG, and a rotary table without a thermostat and with dual shafts being capable of rotating in 360 DEG; and does not introduce secondary mounting errors, thereby ensuring a calibration precision, overcoming restrictions of calibration devices, and well compensating non-orthogonal errors and temperature drift errors. According to the invention, in a full temperature range, a maximum output error of the MEMS gyroscope is only 0.2 DEG / s, and triaxial errors are also consistent.

The invention provides a wing sail which comprises a mast main body, a sail face and at least one telescopic mast. The telescopic mast can move up and down along the mast main body. The sail face is supported by an upper framework and a lower framework, the upper framework of the sail face is fixedly connected with the telescopic mast, and the lower framework of the sail face is fixedly connected with the mast main body. The invention also provides a ship with the wing sail, which comprises an engine and an engine speed regulating device. The ship also comprises a detection device for detecting signals of wind velocity and wind direction, a revolution speed transducer for acquiring the actual revolution speed signals of the engine and a central control system. The central control system is used for calculating the sail angle of the wing sail and the revolution speed of the engine according to the wind velocity and wind direction information acquired by the detection device, controlling the rotation of the mast main body of the wing sail to adjust the sail angle of the wing sail and controlling the speed adjustment device to adjust the revolution speed of the engine. The wing sail and the ship with same have the advantages of energy saving and high safety.

The invention provides a method and system capable of conducting management on a mobile terminal. The method comprises the following steps: after a script application interface (JS API) embedded in a webpage is triggered, related management information of a target mobile terminal is sent to an SDK through a communication channel which is built between the JS API and the SDK installed at the PC end, and the SDK executes management on the target mobile terminal connected with the SDK according to the received related management information. The method can achieve management on the mobile terminal connected to the SDK on the webpage through communication between the JS API embedded in the webpage and the SDK installed at the PC end, gets rid of limitation of a client side, and is simpler and more convenient to operate.

The present invention discloses a sentence similarity calculation method and apparatus and relates to the technical field of automatic correcting. The method comprises: acquiring a vector corresponding to each word; performing syntax analysis on two sentences to be compared so as to acquire words forming compositions of the two sentences; calculating a first cosine distance between the vectors corresponding to the words forming the corresponding compositions of the two sentences; and according to the first cosine distance, determining similarity between the two sentences. According to the method provided by the present invention, by performing syntax analysis on the sentences and structurally holding semantics of the sentences, similarity between the sentences are more accurately calculated; and in addition, the word vectors based on a neural network model are adopted to represent the words, thereby more accurately calculating similarity between the words and getting rid of restrictions of a near-synonym dictionary.

The invention discloses an isothermal amplification kit for detecting SARS-COV-2 and a primer probe set. The kit comprises (1) inactivated lysate; and (2) an isothermal amplification system: a reaction buffer solution Buffer A, magnesium acetate Buffer B, negative control, nuclease-free water, a primer probe set and RAA enzyme. The lysate is used for rapid inactivation and release of viral nucleicacid, an isothermal amplification technology is utilized for rapidly enriching and amplifying a target area, whether a specific amplified product exists is rapidly determined through combination of aprobe with modification groups and a product with biotin, by a lateral chromatography technology and by use of colloidal gold developing. The kit is simple to operate, professional extraction reagents and detection instruments are not required limitation of detection laboratories and professionals is freed, the kit can perform rapid detection in an instrument-free state outdoors, the whole process only needs 30 min, and reading is very convenient.

The invention relates to the technical field of satellite positioning and discloses a three-antenna-array high-precision orientation method and system based on the Beidou system. The method comprises the steps of receiving a BDS signal with antenna arrays and converting the BDS signal into a digital signal; obtaining BDS RNSS satellite ephemeris data according to the digital signal and measuring carrier phase information at the same time; conducting whole-cycle ambiguity resolution on the carrier phase information to obtain positioning data and preliminary orientation data; measuring the base lengths and pitching angles between the antenna arrays, measuring the included angles between the antenna arrays, and conducting iteration on the measuring results again to calculate the azimuthal angle of a baseline vector; conducting comprehensive calculation and coordinate transformation to obtain an orientation result of a point to be measured. According to the three-antenna-array high-precision orientation method and system based on the Beidou system, a complete and high-precision Beidou system navigation and positioning resolving process is formed through the antenna arrays, and a high-precision navigation and orientation positioning technology independent of the GPS technology is realized.

The invention is applicable to the technical field of communication and provides a Baud rate identification method and device for serial communication and monitoring equipment. The method comprises the following steps: (1) carrying out width acquisition of preset times on received high-low level pulse signals respectively; (2) carrying out minimization on the acquired data, and obtaining the greatest common divisor of the minimized data; (3) obtaining a first Baud rate corresponding to the greatest common divisor according to the corresponding relationship between a preset greatest common divisor and a preset Baud rate; (4) re-executing the previous two steps, and obtaining a second Baud rate according to the corresponding relationship between the preset greatest common divisor and the preset Baud rate; and (5) when the first Baud rate is different from the second Baud rate and the number of acquisition times of the second Baud rate is less than that of the preset Baud rate, updating the first Baud rate to the second Baud rate, and returning to execute the step (4) until the first Baud rate and the obtained second Baud rate are the same. Thus, the flexibility and universality of the Baud rate identification method are improved.

The invention provides an automatic wireless charging system based on WiFi positioning and a method of the automatic wireless charging system. The automatic wireless charging system comprises a wireless charging module with the WiFi function, a positioning moving module, a WiFi positioning module and electronic equipment with the WiFi function and the wireless charging function. The electronic equipment is used for sending charging information to the wireless charging module when the electricity quantity of the electronic equipment is smaller than a certain threshold value, the WiFi positioning module is used for carrying out WiFi positioning on the electronic equipment, the positioning moving module is used for moving the wireless charging module to a position within the wireless charging range of the electronic equipment, and the wireless charging module is used for charging the electronic equipment wirelessly. The automatic wireless charging system based on WiFi positioning and the method of the automatic wireless charging system get rid of limitation on charging positions from wireless charging in the prior art, and the electronic equipment can be automatically charged wirelessly at any time and any place as long as located within the working range of the wireless charging module.

The invention provides a magnetic-drive peristaltic soft-body robot based on a magnetic programming temperature-sensitive hydrogel. The magnetic-drive peristaltic soft-body robot comprises a first moving body and a second moving body, the two ends of the second moving body are both connected with the first moving body, and the second moving body is the temperature-responsive hydrogel containing magnetic particles; the first moving body and the second moving body are deformed by applying an alternating magnetic field to the second moving body; and the second moving body is of an upper and lowerdouble-layer structure, the upper layer is a double-network cross-linked hydrogel, the lower layer is a magnetic temperature-responsive hydrogel, the alternating magnetic field is applied to the second moving body, so that the deformation amount of the lower layer is larger than that of the upper layer. According to the magnetic-drive peristaltic soft-body robot, the magnetic field is used for driving the hydrogel to deform, so that wireless control is realized, and the wired restriction is broken.

The invention relates to the engineering geological investigation field, in particular to a multichannel transient Rayleigh wave detection method. The multichannel transient Rayleigh wave detection method includes steps: obtaining arrival time difference tau between two transient Rayleigh waves collected by two wave detectors on two adjacent detection points, wherein setting an interval between the two detection points to be arbitrary large on the premise of guaranteeing invariability of foundation soil properties between the two detection points; figuring out phase difference delta phi(f) among different frequency components of the two transient Rayleigh waves of the two adjacent detection points according to the equation that delta phi(f)=delta phi0(f)+2piftau, wherein defining 2piftau as a time difference phase position between two channels; using a phase difference method to figure out corresponding multichannel transient Rayleigh wave phase speed according to the obtained phase difference. The multichannel transient Rayleigh wave detection method gets rid of fetters of a channel interval by introducing the time difference phase position 2piftau into extraction of the Rayleigh wave phase difference among the different frequency components of the two transient Rayleigh waves, uses the two wave detectors to extract the Rayleigh wave phase difference among the different frequency components of the two transient Rayleigh waves, and thereby significantly improves work efficiency, transverse resolution and high frequency resolution of transient Rayleigh wave detection.

The embodiment of the invention provides a virtual home decoration system based on a mobile Internet and a cloud platform. The virtual home decoration system comprises a data acquisition module, a cloud platform server and a mobile terminal, wherein the cloud platform server comprises a scene modeling module and a virtual home decoration module, the data acquisition module is used for acquiring three-dimensional data of a home decoration object through a data acquisition sensor, the scene modeling module is used for creating a three-dimensional model, including texture information, of the home decoration object based on the three-dimensional data, the virtual home decoration module is used for creating the three-dimensional model of the home decoration object as a virtual home decoration scene according to a decoration requirement, and the mobile terminal is used for browsing or editing a virtual home decoration scene. The virtual home decoration system prevents the limitation of a conventional virtual home decoration system to a PC platform, improves the convenience of a user or a designer using the virtual home decoration system, avoids creation of the three-dimensional model of the home decoration object on a PC or the mobile terminal, reduces hardware requirements of the PC or the mobile terminal, and improves the creating speed of the three-dimensional model.

The invention relates to methods and systems for generating and checking an electronic note with an anti-counterfeiting two-dimension code. The method for generating the electronic note with the anti-counterfeiting two-dimension code comprises the following steps that: an original electronic note picture is read, and a temporary electronic note picture with a defined two-dimension code embedding region is generated; for the temporary electronic note picture, an information abstract algorithm is utilized for calculating abstract data, and in addition, the obtained abstract data is encrypted for generating the anti-counterfeiting two-dimension code; and the anti-counterfeiting two-dimension code is embedded into the two-dimension code embedding region of the original electronic note picture, and the electronic note with the anti-counterfeiting two-dimension code is obtained. The methods and the systems provided by the invention can be used for effectively preventing the tampering and the counterfeiting of the electronic note, and in addition, the diversity and the practicability of the electronic note can be greatly improved.

The invention provides a data processing method and apparatus. The method comprises the steps of receiving a query operation request, wherein the query operation request comprises query parameters, and the query parameters include a first attribute identifier and a first attribute value; sending the first query request to a memory database; receiving a first query response returned by the memory database, wherein the first query response comprises a corresponding first content identifier queried in a index list corresponding to the first attribute identifier according to the query parameters by the memory database; sending a second query request to a key value database, wherein the second query request comprises a first content identifier; receiving a second query response returned by thekey value database, wherein the second query response comprises first data contents corresponding to the first content identifier and found in a key value record by taking the first content identifieras a key value through the key value database; and sending the first data contents to a requester of the query operation request. The method combines the advantages of the memory database and the keyvalue database, and has the advantages of good performance and low cost.

The invention provides a method for a storage interface bypassing a Bio layer to access disk drive, which comprises the following steps of: setting up an equipment module, wherein each disk equipment corresponds to a disk equipment object; packing an IO (Input Output) request initiated by an application program into an IO request object; setting up two stages of queue for each disk equipment: a waiting queue and a processing queue, wherein the waiting queues are used for sequentially receiving the IO request objects, and under the condition that the processing queues have a vacancy, the IO request objects are converted to the processing queues from the waiting queues; and creating a scanning tread for scanning the waiting queues of all the disk equipment objects, if the waiting queues have the IO request objects, the IO request objects are extracted from the processing queues and then are submitted to a bottom layer, and after the IO processing is finished, the IO request objects are removed from the processing queues.

The invention discloses a remote controlling method of intelligent equipment. The method comprises the following steps of enabling a mobile terminal to receive a selection common of a control item for an user to control the controlled intelligent equipment, wherein the control item is positioned in a control interface corresponding to the controlled intelligent equipment, the control interface is in a webpage type, and the control item is a hyperlink icon; enabling the mobile terminal to send a control request command to the controlled intelligent equipment through gateway equipment, so as to control the controlled intelligent equipment, wherein the control request command is a control request command of a HTTP (hyper text transmission protocol) corresponding to the hyperlink icon; enabling the controlled intelligent equipment to receive the control request command of the HTTP of the mobile terminal, and executing an operation command of the contents of the corresponding hyperlink icon, so as to obtain the operation results. The invention discloses the mobile terminal, the intelligent equipment and a system. By adopting the method, the remote controlling method, the mobile terminal, the intelligent equipment and the system can conveniently realize a universal remote controller, and the limitation by the special remote controller is avoided.

The invention relates to an intelligent express delivery device and belongs to the technical field of logistics transport devices. The intelligent express delivery device solves the technical problemof low efficiency of package delivery and pick-up in the prior art. The technical solution comprises a storage area arranged in the front part of a carriage, wherein a storage area unfolding device isarranged on the top of the carriage; an automatic compartment door is also arranged on the top of the carriage; a package pick-up device is mounted at the middle of the bottom of the carriage; the rear part of the carriage is provided with an upper layer and a lower layer; the lower layer is a package sending and pick-up platform; the upper layer of the carriage is an unmanned aerial vehicle package delivery device; and a hydraulic lifting device is mounted between the bottom of the carriage and a carrying vehicle. The intelligent express delivery device applies the technical improvement of the automated storage and retrieval system to an express delivery vehicle so as to achieve a high intensive degree, free the package sending and pick-up from the time limitation, realize the intelligence and unmanned operation of the package sending and pick-up process, save human resources and solve the problem of "the last kilometer" of packages to a greater extent. The intelligent express delivery device conforms to the development trend of "Internet plus express delivery" and is worth popularizing and applying widely.

The invention discloses a microfluid spinning device used for preparing orderly orienting fiber to realize a high-voltage-free, safe, energy-saving and rapid spinning process. The microfluid spinning device comprises a microflow pump 1, a control panel I2, an injection silk projector 3, a plate acceptor 5, an electric rotating machinery 8, a stepping motor translation platform 9, a control panel II14 and a control panel III15. The microflow pump 1 is arranged on the plate acceptor 5, the injection silk projector 3 is arranged on the microflow pump 1 and connected with a dash receiver 6 on the plate acceptor 5 via a needle point 4, the plate acceptor 5 is arranged on the electric rotating machinery 8 arranged on a base 10 of the stepping motor translation platform 9, the stepping motor translation platform 9 is provided with a translation stepping motor 12, the translation stepping motor 12 can control movement in the horizontal direction to control the gap of silk to realize quantitative control of thin silk distance, the electric rotating machinery 8 and the stepping motor translation platform 9 are connected with the control panel II14 and the control panel III15.

The invention discloses a fire fighting and rescue system comprising a vehicle body, a pump, a pipeline, a control system and an aircraft. According to the fire fighting and rescue system, the aircraft is adopted to pull up the pipeline, the height of fire extinguishment can reach 200-1000 m or above, and the construction cost of the system is low, specifically, the price of the system is much less than the price of a current high-grade fire fighting truck.

A mechanical fiber distribution system based on Clos crossing matrix algorithm comprises a main support, a plugging mechanism, a control system, an optical fiber panel and a fiber take-up box. The optical fiber panel is disposed on the main support, and the fiber take-up box is disposed on the optical fiber panel. The optical fiber panel can be controlled by the control system to move along a guide rail on the main support. The plugging mechanism is connected with the control system in a controlled manner and comprises two mutually perpendicular guide rails in horizontal plane and a guide rail perpendicular to the horizontal direction, corresponding sliders are disposed on the guide rails respectively, and a plugging manipulator is fitted to the slider X to the guide rail X transversely in the horizontal plane. The ideal structure meeting the requirements of transmission equipment for crossing matrix is established and is widely applicable to various optical transmission devices. The mechanical fiber distribution system is highly extensible, highly flexible and highly reliable. The limitation on optical switching by capacity is eliminated, loss in optical switching is avoided, and the optical switching for places requiring ultra-large capacity is achieved.

The invention provides a long bit width time sequence accumulation multiplying unit, which comprises a clock, a data operation module and a carry register, wherein the data operation module carries out operation on data to finish various types of work; a full adder is arranged in the data operation module; the full adder segments products obtained by accumulation, and multiplicands into different intervals according to bit width, the bit widths of full adders in different intervals are subjected to addition calculation when the data operation module enters an accumulation working state, and carry information is stored in the carry register; and when a next clock edge comes, the product of the shifted multiplicand and carry data of a previous level is accumulated to generate a new product and carry data, the new product and carry data can be stored in the carry register, and circulation is carried out in the above way until data in a multiplier is completely shifted. The data bit width calculated by the multiplying unit can be infinitely increased so as to get rid of limitation, which is caused by the multiplication data bit width, for the maximum work clock frequency of the multiplying unit, and the multiplying unit can stably work under extremely high clock frequency.

The invention discloses a photoacoustic imaging device free of limitation of ultrasonic transducer frequency bands and a detection method of the photoacoustic imaging device. The photoacoustic imaging device comprises a photoacoustic excitation assembly, a photoacoustic signal detection assembly, a photoacoustic signal collection / processing assembly and a sample platform, the photoacoustic excitation assembly, the photoacoustic signal detection assembly and the photoacoustic signal collection / processing assembly are sequentially connected, the photoacoustic excitation assembly and the photoacoustic signal collection / processing assembly are connected, and the photoacoustic signal detection assembly is connected with the sample platform. According to the photoacoustic imaging device, pulse lasers are used for radiating a biological sample to generate photoacoustic signals, continuous lasers with narrow line width are focused on the surface of the sample, vibration speeds of the surface of the sample are detected to achieve the purpose of detecting the photoacoustic signals, the defect of bandwidth limitation of the transducer is overcome, and the defects that high frequency photoacoustic signals are sharply attenuated in biological tissues and can not be detected are overcome; detection portions are not required to be subjected to any processing, requirements for imaging environment conditions are low, and large pushing functions on clinical performances of photoacoustic technology are achieved.

The disclosed online synchronous explanation and display method for network game comprises: (1) the game client records every player operation in LOG to send into LOG server for storage; (2) the game judge device reads the LOG data through the game client or web displayer, and applies speech device to onsite explain the game procedure; and (3) it transmits the game procedure and speech explanation real time to viewer browser by P2P protocol. This invention is benefit to enjoy online game.

The invention relates to a friction nanometer generator, a preparation method thereof and an application thereof. The upper electrode and the lower electrode of the friction nanometer generator are made of conductive flexible materials, and a first insulating polymer, a first flexible material and a second insulating polymer, a second flexible material and a third insulating polymer are sequentially stacked up to form a film. According to the invention, the friction nanometer generator disclosed by the invention can be attached to an object with a small curvature radius and can reduce the requirements in the longitudinal space or in the transverse space. The limitation of a "heavy" substrate of the generator is avoided. The vertical and independent friction nanometer generator of the invention is ultra-thin in structure and light in weight. In addition, the friction nanometer generator can be attached to objects with complex shapes. Meanwhile, the energy collecting function and the sensing function are achieved. The damage of equipment is avoided. The generator is simple in structure, low in manufacturing cost and capable of being massively produced. The requirements of the currentmarket are met. The invention belongs to the technical field of micro-nano energy power generation.

The invention discloses a method and a system for acquiring a word conversion result. The method comprises the following steps: performing candidate word conversion according to a local word stock aiming at the input content of a user; when the conversion result does not meet a preset condition, transmitting the input content to a server; receiving a word conversion result returned by the server; and displaying the word conversion result to the user. In the method and the system, data and computational resource of the server can be used as the supplementation of local resource so as to get rid of the limitation of the local resource and provide more and better candidate items for the user.

The invention discloses a transformer test data measurement system and a method thereof based on a wireless network. The system comprises a monitoring center, a data acquisition center and a data transfer center; the monitoring center comprises a monitoring center computer, the data acquisition center comprises a plurality of data acquisition controllers and a plurality of special measurement devices, and the data transfer center comprises a Zigbee center wireless module and a Zigbee terminal wireless module; command and data are transferred between the monitoring center and the data acquisition center through the data transfer center; the special measurement devices are used for marking a corresponding actual position at a measurement position selected by the data acquisition controller so as to measure a target sample, transmitting back data through interfaces of the special measurement devices to the data acquisition controller after obtaining a measurement result, and receiving measurement result data; data is processed by the data acquisition controller after obtaining the data, and position information and the measurement result are stored; and then, selection of a next group of measurement positions and measurement operations are sequentially executed, until all the positions are measured.

The invention discloses a method for converting pictures into Chinese ancient poems based on a neural network model. The method includes the following steps of 1, collecting existing Chinese ancient poems to obtain a poem collection data set; collecting picture resources and sentence description resources corresponding to the picture resources to obtain a picture data set; 2, establishing a multi-mode recurrent neural network and training it to generate picture target description sentences; 3, mapping the target description sentences to Chinese key words; and 4, using long-term and short-termmemory networks to establish a Chinese ancient poem generation model and training the model so as to realize the conversion of the pictures to the Chinese ancient poems. The method automatically converts the pictures into the Chinese ancient poems capable of describing the pictures through a computer, gets rid of the limitation of subject words, and enables an ordinary user to generate a corresponding Chinese ancient poem by inputting a picture, thus, to a certain extent, the method can fill China's vacancy in the field of 'writing poems about pictures' with a machine.

The invention discloses a liquefied carbon dioxide energy storage system and application thereof. The liquefied carbon dioxide energy storage system adopts carbon dioxide as an energy storage medium,an artificial container can be used more flexibly, the energy density of the system is improved, the system forms a closed loop, and greenhouse gas can be prevented from being released to the environment; and on the other hand, the liquefied carbon dioxide energy storage system can achieve power grid frequency modulation and peak load shifting, and the renewable energy utilization rate is increased. The liquefied carbon dioxide energy storage system comprises a first compressor, a first cooler, a first hot tank, a first cold tank, a second heater, a first expander, a third expander, a cold regenerator, a throttle valve, a first liquid carbon dioxide storage tank, a second cold tank, a third cooler, a third heater, a second hot tank, a fourth heater, a fifth pump, a third cold tank, a second liquid carbon dioxide storage tank, a third hot tank, a separator, a fourth expander and a fourth cooler.

The invention relates to a file transmission method and system. The method comprises the steps that a first wireless local area network taking a first terminal as a wireless hotspot is established, and a first two-dimensional bar code stored with a hotspot name and an access password of the first wireless local area network is generated and displayed; a second terminal obtains the hotspot name and the access password of the first wireless local area network by scanning the first two-dimensional bar code and accesses the first wireless local area network through the hotspot name and the access password to establish connection with the first terminal; and the second terminal obtains a file selected by a user and sends the file to the first terminal. Through application of the method, the wireless local area network is established by utilization of the wireless hotspot of the first terminal; and the second terminal can transmit the file stored in the second terminal to the first terminal by accessing the wireless local area network. Even if under the condition that no external network exists, the file still can be transmitted. The limit of the external network is eliminated, thereby facilitating operations of a user.

The invention discloses a PPP high precision positioning method based on dual-band GNSS smartphones and relates to the technical field of high precision navigation.AGNSS satellite positioning system with accuracy higher than 10 m is neededfor supporting so that the method can be realized on the dual-band GNSS smartphones. According to the PPP high precision positioning method, through IGS / iGMASmessaging assistance, high precision positioning of the decimeter level or above can be achieved by using a PPP algorithm on GNSS original received data. Preliminary positioning results and original carrier dataprovided by the GNSS satellite positioning system are obtained by thesmartphones through a dual-frequency GNSS receiver, correction data of a precise orbit and a clock correction are achievedthrough mobile internet access IGS / iGMAS system by the smartphones.High precision positioning results are calculated by conducting the PPP algorithm on the smartphones. According to the PPP high precision positioning method, the problem caused by low positioning accuracy of the smartphone now is solved, under the market situation in which the dual-frequency GNSS smartphones gradually become a trend, positioning accuracy of the smartphones is dramatically improved to build infrastructures for location-based service development and better meet high-precision positioning requirements in an era of 5G and internet of things technology.