58results about How to "Good function expandability" patented technology

The present invention discloses a construction site safety helmet wearing detection system and method, belonging to the field of video identification detection. Aiming at problems that mis-identification is easily generated, there are many data requirements of a safety helmet and the identification result is not good in the prior art, the present invention provides a construction site safety helmet wearing detection system and method, a video device and a detection system. The method comprises the steps of: A, collecting video monitoring images, and establishing a detection and identificationmodel; B, collecting real-time monitoring images of a construction site to perform detection of moving objects, and uploading images of the moving objects to an identification system if the images ofthe moving objects are detected; C, receiving the images sent in the step B by the identification system to perform detection and identification and determine the state of a helmet; D, transmitting aresult to a message queue; and E, displaying a detection and identification result. The construction site safety helmet wearing detection system and method can accurately determine whether there is asafety helmet or not, required original data is few and identification is accurate.

The invention discloses a device for measuring a modulation transfer function of an optical system and a method thereof. A target generator of the device comprises a knife edge target (4), a light source (1) and an electrical machine (3), wherein the electrical machine drives the knife edge target (4), so that an inclined angle beta is formed between the arrangement direction of a knife edge pixel (12) of the knife edge target (4) and that of a pixel (13) of an area array detector, and the inclined angle meets the following condition: ds=d sin beta, wherein the ds is a sampling distance, and the d is the size of the edge length of the pixel of the area array detector. When measuring, the modulation transfer function, the electrical machine drives the knife edge target (4) to rotate at the angle of beta to perform image data collecting and data processing so as to obtain modulation transfer function of the optical system to be measured. The invention adopts the knife edge target to realize an oversampling technology and improve the sampling rate, thereby being capable of measuring the modulation transfer function of the optical system to be measured without a relay amplifying system, being capable of measuring the maximum frequency which is higher than the Nyquist frequency of the area array detector, simplifying a measuring system, and avoiding complex assembling and correcting work when manufacturing apparatuses.

The invention discloses a building fire protection linkage system. The building fire protection linkage system comprises a control unit; the control unit is connected with a monitoring system through a WiFi wireless gateway; the control unit is connected with a fire protection detection system, an alarm system, a liquid fire extinguishing system, a gas fire extinguishing system and an emergency aid system through a Zigbee wireless communication module; the control unit, the monitoring system, the fire protection detection system, the alarm system, the liquid fire extinguishing system, the gas fire extinguishing system and the emergency aid system are all connected with a standby power source system; the WiFi wireless gateway is connected with a local control terminal; and the WiFi wireless gateway is connected with a cloud server and a mobile control terminal through the Internet. According to the building fire protection linkage system of the invention, fire protection equipment is connected through a wireless network, and therefore, the influence of a fire source on signals can be decreased; linkage equipment can be monitored and managed in a unified manner through a remote mode, and the influence of the false warning of dangerous cases can be decreased; and the building fire protection linkage system can be in linkage with monitoring equipment and emergency facilities, and therefore, the building fire protection linkage system has high functional extendibility.

The invention relates to a vehicle-borne dynamic traffic information induction system analog design method facing behavior research. The method comprises: building program modules, such as a highway network macroscopic traffic flow simulation model, a traffic flow running state generating module, a driver driving task module, a dynamic road network traffic state and guiding information generatingmodule, a basic travel information generating module, other assistant information generating modules and the like; and driving virtual travel situation taking a computer interface as a carrier. The invention has the characteristics that a driver can go through vivid traffic flow state so as to ensure that the driver behavior data is more reliable, the development cost of a vehicle-borne information system analog program is low, analog tests are simple and easy to operate, test fields are free from limitation, test process is quick, test cost is lower and the like. The invention can provide basic data for driver behavior analysis, vehicle-borne dynamic traffic information system optimization design, operation, evaluation and the like under the environment of traffic information.

The invention discloses an automotive blind spot detection system and method adopting a microwave radar sensor and ultrasonic sensors. The automotive blind spot detection system comprises the microwave radar sensor arranged in the middle of the tail end of an automobile and the ultrasonic sensors symmetrically arranged on two sides of the automobile, wherein the detection zone of the microwave radar sensor covers the rear ends of blind spots, for abutting lanes, of exterior rear-view mirrors and part of visible areas behind the rear ends of the blind spots of the automobile; the detection zones of the ultrasonic sensors cover the front ends of the blind spots for the abutting lanes, of the exterior rear-view mirrors of the automobile; the detection zones of the microwave radar sensor and the ultrasonic sensors wholly cover the blind spots of the exterior rear-view mirrors of the automobile, extending areas of the rear ends of the blind spots and extending detection areas at the tail end of the automobile. The detection performance of the blind spot detection system is guaranteed effectively or even improved, the system cost is reduced effectively, the function extensibility of the system is good, and one preferred scheme is provided.

The invention discloses a motion-sensing music wearable device and a playing motion recognition method thereof. The motion-sensing music wearable device comprises a sensing body and a wearable part connected with the sensing body, wherein the wearable part can be detached and replaced; the sensing body comprises a casing and a nine-axis inertial navigation motion recognition device arranged in the casing, the nine-axis inertial navigation motion recognition device is used for generating playing signals according to playing motions of a human body and transmitting the playing signals to an external intelligent device, so that the external intelligent device can generate playing music according to the playing signals. The motion-sensing music wearable device is good in adaptability and simple and reliable in structural design, can recognize playing motions of different musical instruments and enables people to experience charm of music at any time in any place in a flexible playing manner, the playing manner is highly emulational, and the playing time and place are not restricted.

The invention provides a method for positioning underground people by the visible light communication technology. The method is characterized in that the position of people is determined according to different light intensity at different positions between adjacent LED lamps underground and number information of the LED lamps for lighting a laneway. The system for the method is divided into two parts according to the design, namely, a lighting and control system and a people positioning module, wherein the lighting and control system can be used for displaying the position information of people underground in real time and controlling miner lamps; the miner lamps send each number information in a form of a light signal, and PIN photoelectric tubes positioned around the miner lamps are utilized to receive the light information from moving miner lamps; the people positioning module is used for recording and handling with the position information of the people underground and sending out the position information of the people underground through the moving miner lamps carried by the people underground. With the adoption of the method, the people can be positioned, and requirement for lighting underground is also met; in addition, the advantages of being free of radio-frequency radiation and high in safety are brought.

The method comprises: when the files in the computer is transmitted to the mobile terminal, in the first, an initialization is executed; selecting a source file to be transmitted to the computer; the communication thread of computer uses signal mechanism to make real-time task communication with the mobile terminal; creating a target file used for writing data in, and opening the target file; the communication thread reads data from source file and packaging it into the writing file signals, and then packages the signals into the data frame in link layer, and sends the data frame to the mobile terminal through serial port; after confirming that the data is successfully written in, the remaining data is transmitted out using same way; after completing the transmission, the computer informs the file system of the mobile terminal to close the target file and to release the serial port and each relevant thread.

The invention relates to the technical field of vehicle coming monitoring in railway or highway transportation, and specifically relates to a method and a device for monitoring vehicle coming on a railway based on geomagnetic anomalies. The prior art has problems of a complex system, high power consumption and high cost, and accuracy is susceptible to external environments in the prior art. To overcome the problems of the prior art, the technical scheme of the invention is the method for monitoring the vehicle coming on the railway based on the geomagnetic anomalies. According to the method provided in the invention, geomagnetic field anomalies caused by ferromagnetism components on a train are sensed by using aeolotropic-type magnetoresistive sensors, and processing and analysis are performed on signals acquired by using the sensors to determine the vehicle coming situations on railway lines. The method and the device provided in the invention has a simple structure, extremely low power consumption, low manufacturing cost and low usage cost, and is applicable to long term field monitoring.

The invention relates to the field of machine vision, in particular to a non-contact spatial gesture intelligent lock system. Hardware of the system is sequentially connected with an image sensor, a register and a microprocessor, an output end of the microprocessor is connected with an input end of a touch display screen through a touch display screen interface, the image sensor is an CMOS (complementary metal oxide semiconductor) image sensor OV7670, image data acquired by the image sensor are 16-bit 565RGB format data, the register is a register AL422B, the microprocessor is a microprocessor STM32F103, and the touch display screen is a touch display screen ILI9325. The system has the advantages that the system is low in power consumption, simple in operation process, low in cost and late maintenance charge, high in safety, small in size, fine in functional expansibility and suitable for industrial popularization, and has wide market prospect and use values.

The invention discloses a teaching practical training and checking system and a teaching practical training and checking method. Two functions including scene intervention and behavior recording are designed in the system; the scene intervention is introduced and a plurality of learning scene disturbance terms are formed in a learning process, so that learners do not just mechanically simulate, but can think deeply on the basis of simulated trainings to form own abilities and skills; through the adoption of the behavior recording is adopted, the operation of the learners is monitored at any time in the learning process of the learners, and correct and incorrect operation is recorded and uploaded to a server for carrying out data mining, so that on the one hand, whether a teaching effect of teaching equipment is good or not can be analyzed; on the other hand, whether the learners learn the skills or not after the equipment is used can be analyzed; if the learners do not learn the skills, reasons can also be analyzed; and the system provides a new teaching feedback method to solve the problems of existing mode that only teaching is carried out, but the effect is not considered.

The invention provides a brake lamp control system based on a CAN network and a control method thereof to improve the security of driving. The system comprises an input end, a brake controller, and an output end. The input end comprises wheel speed sensor input, downhill auxiliary switch input, electronic hand brake switch input, brake normally open switch input, gear signal input, engine controller signal input, and radar ranging controller input used to measure the safe distance in front of a vehicle. The output end comprises a brake connected with the brake controller, and a vehicle body controller connected with a brake lamp. The wheel speed sensor input, the downhill auxiliary switch input, the electronic hand brake switch input and the brake normally open switch input are connected with the brake controller by a rigid line. The gear signal input, the engine controller signal input and the radar ranging controller input are connected with the brake controller by a CAN bus. According to the invention, various driving conditions of a vehicle are judged, vehicle braking is executed when there is danger but the driver fails to react, and the vehicle body controller is requested to turn on or off the brake lamp to reduce the occurrence of accidents.

The invention relates to a stretcher system for aviation. The stretcher system is generally mounted on large aircrafts like transport aircrafts and used for the aircrafts to transport the sick and wounded. The stretcher system is composed of supporting arm components, oxygen supply and calling equipment, uprights, a transverse stay bar, inclined stay bars, a fork-shaped joint, a base and quick-demounting pins, and the stretcher system is used for the aircrafts to transport the sick and wounded and can meet oxygen supply and calling needs of the sick and wounded. Mounting of the stretcher system on an aircraft does not depend on the cabin wall and the top of the aircraft, and the stretcher system is directly connected with an aircraft floor through quick-demounting point locking pins and guide rail locking components, so that the stretcher system is convenient to mount and demount, flexible in installation layout and stable in structure, meets airworthiness standards and has obvious advantages in the aspects of carrying capacity, mounting mode, functional expansion and universality when compared with existing products.

The invention relates to a technology for measuring the modulation transfer function of an optical system, in particular to a device and method for measuring the modulation transfer function of a large-numerical aperture micro objective. An image analyzer (11) of the device comprises a scanning knife edge (8), a scanning controller (9), an integrating sphere (10), a semiconductor photoelectric detector (12) and a phase-locking amplifier (13), wherein the scanning knife edge (8) is installed in front of the opening of the integrating sphere (10); the scanning controller (9) receives control signals sent by a control and data processing system (14) to drive the knife edge to move; and the semiconductor photoelectric detector (12) is installed on the inner wall of the integrating sphere (10), and current signals output by the semiconductor photoelectric detector (12) are processed by the phase-locking amplifier (13) and then input to the control and data processing system (14). The device has the advantages of simple structure, good function expansibility, wide working waveband and convenient use and can also be used for measuring the modulation transfer function of the optical system.

The invention provides an intelligent quarantine and disinfection system for entry and exit port vehicles. The intelligent quarantine and disinfection system is characterized in that a chemical flow outlet of a disinfectant generator is connected with an electromagnetic flow instrument B, an outlet of a water tank is connected with an inlet of a booster pump, an outlet of the booster pump is connected with an electromagnetic flow instrument A, both an outlet of the electromagnetic flow instrument A and an outlet of the electromagnetic flow instrument B are connected with an inlet of a proportioning pump, an outlet of the proportioning pump is connected with an inlet of a heater, an outlet of the heater is connected with an inlet of a sterilization detection device, an outlet of the sterilization detection device is connected with an inlet of a high-pressure pump, a magnetic valve and a spray head are arranged in the outlet direction of the high-pressure pump, a water trough is connected with a water circulating device, and an outlet of the water circulating device is connected with an inlet of a filter. The intelligent quarantine and disinfection system has the advantages of being good in energy-saving and environmental protection effect, high in waste liquid recycling rate, stable in disinfectant proportioning concentration, high in intelligent degree and capable of meeting the actual demands of enterprises and the market.

The invention discloses a near-bottom dragging type random receiving cable earthquake data collection system and method. The system comprises a laboratory control table, a dragging framework and a dragging cable. The collection method comprises five steps including system configuration, system distribution, data collection, system recovery and data processing. The system and the method use the technical scheme of arranging hydrophones on a receiving path in random positions; the functions of reducing the effective path space, improving the transverse resolution ratio and efficiently performingcollection are realized; the design of combining and connecting a plurality of sub sections is used, so that the system combination and expansion are conveniently and flexibly completed; and high adaptation capability is realized on an observation object.

The invention discloses a modular hydrogen burning explosion experiment research system with a circulation loop and a method. The system comprises a cylindrical test body and a data measurement subsystem, wherein the test body comprises a plurality of modular pressure-bearing cylinders, and the modular pressure-bearing cylinders are sequentially connected in series and communicated; a plurality ofmeasuring points are arranged in each modular pressure-bearing cylinder, and each measuring point is electrically connected with the data measuring subsystem; an ignition device is arranged at one end in the test body; a plurality of annular pore plate turbulent flow arrays are arranged in each modular pressure-bearing cylinder; the device further comprises a gas injection subsystem, a vacuumizing subsystem and a gas circulation subsystem, the gas injection subsystem is communicated with one side of the test body, and the other side of the test body is communicated with the vacuumizing subsystem; and the gas circulation subsystem is communicated with the test body to form a gas closed circulation loop. The system has the characteristics of modular design characteristics, simple assembly and high flame combustion speed measurement precision.

The invention discloses a pipeline leakage monitoring device which comprises a power supply module, a data acquisition module, a communication module and an embedded control module, wherein the embedded control module is connected with the power supply module, the data acquisition module and the communication module and used for acquiring power supply by virtue of the power supply module, controlling the data acquisition module to acquire pipeline operating state parameters and transmitting the pipeline operating state parameters to a pipeline leakage monitoring system central station by virtue of the communication module.

The invention relates to the technical field of massagers, and discloses an electrode assembly, a neck massager and wearable massage equipment; the electrode assembly comprises an elastic carrier anda flexible circuit board. One side of the flexible circuit board is attached to the elastic carrier, and the flexible circuit board can elastically deform along with the elastic carrier at any angle;an electrical stimulation circuit layer is arranged on the side, away from the elastic carrier, of the flexible circuit board, and the electrical stimulation circuit layer is electrically connected with the flexible circuit board. The electrical stimulation circuit layer is used for applying stimulation current to a human body. The fitting performance of the electrode assembly and the skin of a user is relatively good, and the function expansibility of the electrode assembly is relatively good due to the adoption of the flexible circuit board.

The invention provides a national anti-counterfeiting tax control system based on data security of a server, and relates to an anti-counterfeiting tax control system for storing all information of an (value-added tax) invoice to the server and transferring basic data security insurance to a database of a network. A universal serial bus (USB) KEY (or / and a digital certificate) which has functions of a key and a certified signature, encryption and authentication of a data field on the invoice, and verification of a drawee and a drawer of a specific invoice and a tax authority through the information of the invoice cannot be removed. By the national anti-counterfeiting tax control system, the abnormal complexity and the abnormal hugeness of the national (value-added tax) anti-counterfeiting tax control system on the basis of the conventional integrated chip (IC) card technology and evolutionary improvement and high cost, particularly the cost of a tax payer due to the abnormal complexity and the abnormal hugeness can be avoided. In the invention, the system is simplified greatly and has higher security, lower development running cost and extremely high functions and system expansion capability.

The invention provides an intelligent quarantine and disinfection system for entry and exit port vehicles. The intelligent quarantine and disinfection system is characterized in that a chemical flow outlet of a disinfectant generator is connected with an electromagnetic flow instrument B, an outlet of a water tank is connected with an inlet of a booster pump, an outlet of the booster pump is connected with an electromagnetic flow instrument A, both an outlet of the electromagnetic flow instrument A and an outlet of the electromagnetic flow instrument B are connected with an inlet of a proportioning pump, an outlet of the proportioning pump is connected with an inlet of a heater, an outlet of the heater is connected with an inlet of a sterilization detection device, an outlet of the sterilization detection device is connected with an inlet of a high-pressure pump, a magnetic valve and a spray head are arranged in the outlet direction of the high-pressure pump, a water trough is connected with a water circulating device, and an outlet of the water circulating device is connected with an inlet of a filter. The intelligent quarantine and disinfection system has the advantages of being good in energy-saving and environmental protection effect, high in waste liquid recycling rate, stable in disinfectant proportioning concentration, high in intelligent degree and capable of meeting the actual demands of enterprises and the market.

The invention discloses a display screen driving method and system based on an FPGA (Field Programmable Gate Array) in the technical field of video signal processing, and aims to solve the problems that in the prior art, a display screen needs to convert received HDMI (High Definition Multimedia Interface) signals into MIPI (Mobile Industry Processor Interface) signals by adopting a special chip, but the development of the special chip is not flexible, the technical problem that the functions of character picture display, contrast adjustment and the like after the signal is disconnected do not have advantages is solved. The method comprises the following steps: in response to generation of an external time sequence signal, transmitting a video signal corresponding to the external time sequence signal to a display screen; and in response to disappearance of the external time sequence signal, transmitting the pre-generated character picture to the display screen.

The invention provides a host used for satellite communication. The host comprises host main board, a power supply, an antenna unit and a handheld terminal; the host main board is respectively connected with the antenna unit, the power supply and the handheld terminal; the antenna unit comprises a Beidou satellite antenna, a Beidou / GPS antenna and a WIFI antenna; the host main board is respectively connected with the Beidou satellite antenna, the Beidou / GPS antenna and the WIFI antenna; and a first SIM card slot is formed in the host main board. The invention also provides a control method of the host used for satellite communication. A standard voice and high-speed data service is provided when the host is connected with a Beidou satellite network through the antenna, so that a network operating system can be run, an email can be accessed, a network can be connected, a voice call can be made, the improvement of enterprise operating efficiency and convenience in personnel communication are realized, and cost is reduced.

The invention discloses an automobile voltage-stabilized starting power supply, comprises a housing, a charging line positive electrode, a charging line negative electrode, a charging indicator lamp,a power supply indicator lamp, an overcurrent and overvoltage indicator lamp, a display screen, a startup switch, a USB interface, a charging interface, a transmission line, a solar panel, a control panel, a charging cell, a charging control module, a microprocessor, an overcharge and overdischarge protection module, a discharge control module and a display device. The invention has the advantagesthat: the design of the power supply for the voltage-stabilized starting of the automobile is reasonable, the output port of the charging control module is connected with the battery cell through a transmission line, the input port of the charging control module is connected with the charging interface through a transmission line, and the charging control module is connected with the solar cell panel through a transmission line, when the battery cell is short of power, the battery cell can be inserted into the alternating current through a charging interface, the current fills the battery cell through the charging control module, and when there is no alternating current, the solar cell panel supplies power to the battery cell.

The invention discloses a mechanical type external chest compression device. The device comprises an outer barrel, a driving device is arranged inside the outer barrel, the lower end of the driving device is fixed to the bottom of the outer barrel through connecting pieces which are arranged in the radial direction, the upper end of an output shaft of the driving device is connected with a revolving shaft, two driving protrusions are arranged on the outer side face of the revolving shaft in the circumferential direction, and the upper end of the outer barrel is connected with a top cover; a cam jacking rod is arranged between the driving device and the outer barrel, the upper end face of the cam jacking rod is a concave-convex curved surface, long-strip holes are formed in the side wall of the cam jacking rod, the connecting pieces are placed in the long-strip holes so that the connecting pieces can be adapted to the axial motion of the cam jacking rod, a return spring is arranged in an inner chamber of the cam jacking rod, and the lower end of the cam jacking rod extends out of the outer barrel and is connected with a compression plate. The mechanical type external chest compression device is simple in structure, easy to machine and produce, low in cost, small in size, compact in structure, low in weight, convenient, fast, few in transmission components, high in transmission efficiency, low in energy loss and beneficial to battery life.

A sensor installation device for an acoustic wind tunnel test is provided. A wire mesh array is used in the sensor installation device, and the sensor installation device is composed of a wire rope, aconnecting rod, a fixing bolt and a wire rope tightener. One end of the connecting rod is connected with the fixing bolt, and the other end is connected with the wire rope or the wire rope tightener;the fixing bolt can be pre-installed in the wall surface of the wind tunnel test section, and can also be temporarily installed as needed; and after installation, the wire rope and the connecting rodare tightened by using the wire rope tightener to achieve the required tension, and then the intersection of the wire rope is fixed by using the thin steel wire, the ribbon, or the like. The sensor installation device can be used for the installation of sensors in the measurement of characteristics of the sound field and flow field, especially the lateral sound field or flow field in the wind tunnel, and has the advantages of light weight, simple installation, a small influence on the flow field and sound field, a low cost and strong function expansibility.

The invention provides a steering wheel switch control system of a vehicle and a control method thereof, and belongs to the field of vehicle control. The steering wheel switch control system comprisesa steering wheel touch device and an entertainment host which are in communication connection, and the steering wheel touch device is arranged on a steering wheel and used for receiving and recognizing touch operation of a user and sending operation information corresponding to the touch operation to the entertainment host; and an operation logic program is arranged in the entertainment host andis used for generating a control instruction corresponding to the touch operation according to the operation information and the current playing content and executing the corresponding operation according to the control instruction. The invention further provides a control method of the control system, the computing power advantage of the entertainment host can be exerted, and system upgrading andfunction updating are facilitated.

The invention provides a method for simulating key operation by tapping a microphone array. The method includes the following steps: S1, setting and initializing a tapping event start flag and a timer; S2, taking a 10 ms data as a basic processing unit, and reading collected data of a microphone; S3, detecting whether the collected data meets variation characteristics of a tapping signal or not, and if so, entering S4; if not, adding a '0' at the end of the data sequence, and entering S5; S4, calculating the zero-crossing rate of the collected data, judging whether the collected data is a tapping signal or not according to the zero-crossing rate, and if so, adding a '1' at the end of the data sequence; If not, adding a '0' at the end of the data sequence; S5, intercepting a complete tapping event; S6, searching a corresponding desired operation from the mapping list according to the intercepted tapping event, and performing the desired operation. According to the method for simulatingkey operation by tapping a microphone array, the function of completing the desired operation of users by tapping the microphone is achieved, and inconvenience caused by operation of the remote controller in the past can be effectively overcome.

The invention discloses a plug-in type three-way normally-closed hydraulic-control reducing valve which is characterized by comprising a retainer ring (1), a valve core (2), a valve body (3), a spring(4), three operating windows and a window control port X for control, wherein the three operating windows comprise an inlet P, an outlet A and a return opening T; the outlet is positioned between theinlet and the return opening; a control chamber (13) is formed among the valve core, the retainer ring and the valve body; the control chamber is communicated with the control port; a spring chamber(6) is formed between the valve core and the valve body; n communicated inner holes are formed in the valve core; the inner holes are communicated with an outlet; the spring chamber is communicated with the inner holes; the valve core is in matched with the valve body by virtue of a minimum clearance; the diameter dimension of a matching surface of the valve core and the control chamber is largerthan the diameter dimension of a matching surface of the valve core and the spring chamber; a spring is arranged in the spring chamber; the retainer ring, the inlet, the outlet and the return openingare formed in the valve body; and the control port is formed in the retainer ring. According to the reducing valve disclosed by the invention, a zero pressure state of the outlet can be realized, other branches are not influenced when one pump station drives multiple loads and a single branch is in a completely zero pressure state.

The invention provides a piezoelectric sensor-based structure health evaluation software platform realization method. The method includes the following steps: first, software platform building based on a Microsoft C / C++ compiler, namely VC (MicroSoft Visual C / C++), and a Microsoft foundation class library, namely MFC (Microsoft Foundation Classes); second, realization of software data interfaces;third, software realization of algorithms; and fourth, realization of software functions. Through the above steps, the piezoelectric sensor-based structure health evaluation software platform realization method is completed in the invention, and can evaluate a health condition of a structure; and in addition, a software platform encapsulates each function into a module, each module can independently run, program function expansibility, portability and secondary development performance are good, and practical engineering application is facilitated.