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Wireless Network has become the critical part of the communication infrastructure in our environment. Nowadays, the using of mobile computing devices such as laptops and Wi-Fi enabled phones in the workplace is increasing. The design of wireless networks for enterprise environments remains a challenging task due to the problem of topological design. In this paper, we discuss the computational aspects of the task of calculation the various criteria of efficiency wireless networks' topology. These criteria determine the different characteristics of wireless networks - the access level of populations to network services, the level of the distributed signal and the level of signal accepted in the city. We use brute force algorithm for comparing the different criteria of efficiency the topology of wireless networks. The brute force algorithm has high computational complexity therefore in our experiments we use parallel computing to solve the problem. For illustration the results we use the task of optimization the Wireless network topology for fragment of Myanmar territory.
This paper discusses an approach of the abnormal condition detection of whole blood using piezo-synthetic effects in blood under dynamic external pressure. Three groups of samples having verified chemical and biological conditions were analysed to prove reliable detection: saline, whole blood and whole blood with colorectal cancer as an example of abnormal conditions. The procedure of a discrete differentiation process for obtained experimental data has been proposed as preliminary processing. Three information parameters have been selected to describe experimental data. Fischer F-statistics were used to determine the information content of the proposed information parameters. It has been proved that the proposed information parameters react on changing state of object under test and therefore can be effectively used for the abnormal condition detection.
Synthesis of serving policies for objects flow in the system with refillable storage component
(2017)
This paper discusses the solution of the logistic problem occurred in a management system to supply fuel to inhabitants in the Arctic regions using bulk water transport delivery. The suggested mathematical model of a logistic scheme is designed in the form of uniprocessor system with refillable storage component providing a single stage service of deterministic objects flow. The task scheduling optimisation problem is formulated in the way where service policies are estimated by two independent minimised criteria. Proposed synthesis algorithm of Pareto-efficient service policies utilises a bicriterial approach of dynamic programming. The algorithm has been verified by the simulation example.
The paper analyses computational model based on dynamic programming for platforms with multicore processors and heterogeneous architectures with FPGA. The models are applied for solving a canonical problem of dispatching where the computation time significantly depends on the problem scale factor. The parallel algorithms of NP-hard problem of dispatching are complicate and require intensive RAM data exchange. In order to reduce the computation time, it is suggested to use FPGA as a coprocessor providing massively parallel computation and increase the operational performance of the system in one order.
The small and remote households in Northern regions demand thermal energy rather than electricity. Wind turbine in such places can be used to convert wind energy into thermal energy directly using a heat generator based on the principle of the Joule machine. The heat generator driven by a wind turbine can reduce the cost of energy for heating system. However the optimal performance of the system depends on the torque-speed characteristics of the wind turbine and the heat generator. To achieve maximum efficiency of operation both characteristics should be matched. In the article the condition of optimal performance is developed and an example of the system operating at maximum efficiency is simulated.
Power train models are required to simulate hence predict energy consumption of vehicles. Efficiencies for different components in power train are required. Common procedures use digitalised shell models (or maps) to model the efficiency of Internal Combustion Engines (ICE) and manual gearboxes (MG). Errors are connected with these models and affect the accuracy of the calculation. The accuracy depends on the configuration of the simulation, the digitalisation of the data and the data used. This paper evaluates these sources of error. The understanding of the source of error can improve the results of the modelling by more than eight percent.
This paper discusses the analysis of mechanical power flow in an electric motor drive operating under variation of conditions. The drive system vibration generates the oscillation in the supplied active power which can reduce performance of the system and increase the actual load on the shaft. It is shown that the vibration damper installation significantly decreases the oscillations in mechanical power flow on the motor shaft and improves characteristics of the system operation. The paper provide analysis of two models of the electric drive installed on the platform - the system which is quipped with vibration dampers and without.
This paper demonstrates a possibilities of using brute force methods for evaluating the effectiveness of hierarchical management systems. Proposed model of hierarchy provides finding the optimal distribution of load between the executive elements at a predetermined structure. A simple hierarchical structure has been used as an example to investigate the functionality of the model and its software implementation.
The classification of median filter hardware structure was proposed. Main differences, advantages and disadvantages of each class were described. Scalable and synthesizable Verilog-descriptions were designed for two fast hardware structures. HDL-descriptions were synthesized on Altera and Xilinx FPGA platforms, comparative analysis on the basis of resource utilization and clock rate was done.
The paper presents a new control strategy of management of transport companies operating in completive transport environment. It is aimed to optimise the headway of transport companies to provide the balance between costs and benefits of operation under competition. The model of transport system build using AnyLogic comprises agent-based and discrete-event techniques. The model combined two transport companies was investigated under condition of the competition between them. It was demonstrated that the control strategy can ensure the balance of interests of transport companies trying to find compromise between cost of operation and quality of service.
The most important component of a closed-loop industrial control system is the communication unit located between a digital controller and the object being controlled. A pulse converter is usually used for this purpose in systems operating under pulse width modulation. However the dynamic characteristics of the converter bring a significant impact on the quality of the system regulation. This article discusses the design and implementation a closed-loop digital automatic control system for a zero-current switching quasi-resonant boost converter. It enables a high-speed transient process of the controlled object voltage having the advantages provided by pulse methods of electrical energy conversion. This paper also presents the simulation and experimental verification of the proposed approach.
Error analysis in a high accuracy sampled-data velocity stabilising system using Volterra series
(2015)
The paper presents a new method of analysis of error in a sampled-data velocity stabilising system operating under wide range pulse width modulation. The analysis is based on multi-channel model of the system obtained as a result of approximation of pulse-modulated signal from the output of a PWM converter. Approximation of piecewise-linear modulation characteristics of each channel was obtained as a series expansion of Hermite polynomials where the expansion comprises two polynomials of the first and third orders. Transfer functions of each channel and a closed-loop system were obtained using a multidimensional Z-transform based on Volterra series. The analytical expression of error under impact of a step input was derived using the transfer function of the closed-loop system. A DC electric drive was used as an example of high accuracy sample-data stabilising system in order to simulate and verify the proposed method.
This paper presents the development of Modelica model for the youBot manipulator. Whereas other robotic simulations focus on the robot interaction with its environment, Modelica allows the modeling of the manipulator controllers and motors. The model was developed with a Modelica library for the manipulator’s components which provides modularity, reusability and abstraction. A comparison test with the actual system has been performed to ensure the model accuracy. The test shows promising result and provides possible future work. The Modelica model of the youBot manipulator is freely available.
This paper presents a new method of analysing the error of a sampled-data velocity stabilising system with a wide range of pulse width modulation. The analysis is based on multi-channel model obtained as a result of approximation of pulse-modulated signal at the output of a PWM converter. Approximation of piecewise-linear modulation characteristics of each channel has been obtained as a series expansion of Hermite polynomials where the expansion comprises two polynomials of the first and third orders. The transfer function of every channel and a closed-loop system has been obtained using multidimensional Z-transform. The analytical expression of an error under impact of a step input has been derived using a transfer function of the closed-loop system. A dc electric drive has been used as an example of high accuracy sample-data stabilising system to verify and demonstrate the proposed method.
This paper proposes a new artificial neural network-based maximum power point tracker for photovoltaic application. This tracker significantly improves efficiency of the photovoltaic system with series-connection of photovoltaic modules in non-uniform irradiance on photovoltaic array surfaces. The artificial neural network uses irradiance and temperature sensors to generate the maximum power point reference voltage and employ a classical perturb and observe searching algorithm. The structure of the artificial neural network was obtained by numerical modelling using Matlab/Simulink. The artificial neural network was trained using Bayesian regularisation back-propagation algorithms and demonstrated a good prediction of the maximum power point. Relative number of Vmpp prediction errors in range of ±0.2V is 0.05% based on validation data.
Predefined heater parameters are involved in self-tuned temperature control for plastic moulding. However the heater system transfer function depends on many external parameters, such as barrel filling level, type of plastic etc. This paper discusses a recursive least-square estimation of plastic moulding heater parameters identification. The real heaters have been estimated by recursive least-square method as 2nd or 3rd order transfer function having an error less than 7.5%. The optimal sampling time for the identification process of different heater cartridges has been obtained from Matlab simulation. The parameters of estimated model can be used in self-tuned temperature controllers for injection plastic moulding heater.
This paper presents a new method of analysing the error of a sampled-data velocity stabilising system with a wide range of pulse width modulation. The analysis is based on multi-channel model obtained as a result of approximation of pulse-modulated signal at the output of a PWM converter. Approximation of piecewise-linear modulation characteristics of each channel has been obtained as a series expansion of Hermite polynomials where the expansion comprises two polynomials of the first and third orders. The transfer function of every channel and a closed-loop system has been obtained using multidimensional Z-transform. The analytical expression of an error under impact of a step input has been derived using a transfer function of the closed-loop system. A dc electric drive has been used as an example of high accuracy sample-data stabilising system to verify and demonstrate the proposed method.
Battery of a plug-in electric vehicle can be charged from a power grid at different locations. In case of charging at home location it performs a significant impact on household energy consumption and needs to be coordinated and scheduled in order to reduce peaks of power load and cost of electricity. This paper discusses coordination of in-home charging aimed to improve load factor and reduce cost of consumed energy. The algorithm of coordinated charging is based on prediction of household appliances load profile and used to control the electric vehicle battery charger. The simulation has been conducted to verify the proposed algorithm.
The paper discusses utilisation of the brute force methods for the task of towers distribution in wireless communication systems. The proposed algorithm allows to find an optimal allocation of a tower between the settlements. A simple wireless communication has been used as an example to investigate the functionality of the algorithm's software.
The paper analyses a random pulse width modulated technique applicable for Z-source inverter. The proposed technique comprises the random pulse position PWM with a randomised frequently triangular carrier having characteristics of both space vector and random lead-lag modulations. This random pulse PWM is produced through the logical comparison of the pseudorandom binary sequence bits with the PWM pulses corresponding to two fixed frequency triangular carriers. Matlab/Simulink was used for modelling and simulation of the proposed method. It has been found that the output harmonic spectra of a Z-source inverter operating under the PWM with randomised frequency are dispersed and continuously distributed that can significantly reduce acoustic noise generated by the inverter and the load.
This article introduces and discusses the development of a low-cost Rapid Control Prototyping Platform (RCPP). The aim of RCPP is to automate design of control algorithm of electromechanical actuators and simultaneous implementation it into a target microprocessor. The RCPP is stand-alone system containing software tools and electronic hardware in order to provide all development steps from system identification, model-based control design and code generation up to hardware implementation. The system can be used for development of a torque, speed or position controller for low power electromechanical actuators especially in the area of automotive application. The hardware of the platform is based on a 16-bit microcontroller and includes essential power semiconductor switches, sensors and communication interfaces. The presented RCPP system supports Real-Time-Work interface of MATLAB/Simulink and Calibration Protocol for CAN-Bus communication.
The introduction of new steering conceptsSteer-by-Wire (SBW) gives possibility to replace theconventional steering wheel by an alternative userinterface such as a sidestick. In SBW system the sidestickcan be used as user input element instead of a steeringwheel. The implementation of sidestick in the Human-Machine-Interface (HMI) allows combiningthe conventional steering consisting of a steeringwheel, an accelerator and a brake pedal into a singleelement. Also the implementation of the sidestickcreates new, interesting and flexible design optionswhich can be used to transform the driver’s spatialenvironment. This article describes an active sidestickfor a vehicle which has been developed, integrated andtested in accordance of haptic, ergonomic and safetyrelevant requirements. The control strategies used forthe active attenuators of the sidestick have beeninvestigated and optimised using a Simulink model.
The article presents a solution to detect rotor position at stand still condition for all types of permanent magnet brushless dc motors. The solution provides both secure and fast method for starting of the brushless motor, that is independent on the sensorless control scheme used. Nonlinearities found in standard three phase permanent magnet dc motor are used to derive the rotor position at stand still. The described solution assumes that there is availability of the neutral point of the three phase star motor windings.
This paper provides a performance analysis of a wearable photovoltaic system mounted on the outer surface of a backpack. Three types of photovoltaic materials, commonly used for electricity generation, have been investigated under various conditions including sun irradiance, angle-of-incidence and sun inclination. The results of the investigation have shown that the system equipped with the rigid mono-Si panels performs 3.5 to 4.9 times better than the system equipped with a-Si flexible PV modules. The average power generated by the wearable photovoltaic system is about 30% of the maximum installed power for any photovoltaic type. This paper presents the test data resulting from the evaluation of the daily energy production of a wearable photovoltaic power supply.
This paper proposes a new artificial neural network-based position controller for a full-electric injection moulding machine. Such a controller improves the dynamic characteristics of the positioning for hot runners, pin valve and the injection motors for varying moulding parameters. Practical experimental data and Matlab’s System Identification Toolbox have been used to identify the transfer functions of the motors. The structure of the artificial neural network, which used positioning error and speed of error, was obtained by numerical modelling in Matlab/Simulink. The artificial neural network was trained using back-propagation algorithms to provide control of the motor current thus ensuring the required position and velocity. The efficiency of the proposed ANN-based controller has been estimated and verified in Simulink using real velocity data and the position of the injection moulding machine and pin valve motors.
