Wlodek Kulesza

The problem of applying modern uncertainty concepts to the measurement of instrument specific parameters

This paper present discusses a number of problems that occurs when implementing GUM to modern instruments. These are often automatic which makes it difficult to evaluate the uncertainty components in each measurement step, since it is difficult to control and analyses them. Many of these instruments try to quantify instrument specific parameters, parameters that are difficult to compare with other ones having the same dimension but being measured with another technique. Often these parameters lack traceable calibration which may result in a sizeable uncertainty component. This article also includes the human part of the measurement process.

Planning of a Multi Stereo Visual Sensor System - Depth Accuracy and Variable Baseline Approach

This paper presents a method for planning the position of multiple stereo sensors in an indoor environment. This is a component in an intelligent vision agent system. We propose a new approach to dynamically adjust the multiple stereo pairs position, pose and baseline length in 3D space in order to get sufficient visibility and enough accuracy for surveillance, tracking and 3D reconstruction. The paper proposes visibility constraints to plan the cameras pose, and a depth accuracy constraint to control the baseline length. The minimum number of stereo pairs necessary to cover the target space is optimized by an integer linear programming. The 3D simulations of reconstruction accuracy and the human activities space coverage problem were performed in Matlab.

A Simplified Behavioral MOSFET Model Based on Parameters Extraction for Circuit Simulations

This paper presents results on behavior modeling of a general purpose metal-oxide-semiconductor field-effect transistor (MOSFET) for simulation of power electronics systems requiring accuracy both in steady state and in switching conditions. Methods of parameters extraction, including nonlinearity of parasitic capacitances and steady-state characteristics, are based on manufacturer datasheet and externally measurable characteristics. The MOSFET template is written in the MAST language and simulated in the SABER simulator. Experimental validation of the N-channel power MOSFET-type IRFP240 (Fairchild Semiconductor) rated at 20 A/200 V is performed in a dc/dc boost converter. The main features of the developed model have been compared with the properties of an analytical MOSFET model and a general MOSFET model embedded to a SABER simulator.

Mutual Coupling Suppression Between Two Closely Spaced Microstrip Antennas With an Asymmetrical Coplanar Strip Wall

This letter describes an asymmetrical coplanar strip (ACPS) wall to suppress the mutual coupling between two closely spaced 5.8-GHz microstrip antennas. The ACPS wall, which is inserted vertically between the two antennas, introduces an additional coupling path to reduce the antenna coupling, occupying just a small area between the two antennas. The decoupling effect of the proposed structure is verified by the simulation and measurement. The experimental results show that the achieved isolation is better than 35 dB and reaches a maximum of 54.3 dB at 5.8 GHz, with an extremely close antenna distance of 0.03λ0 (edge-to-edge distance). The measured patterns indicate that the proposed structure also improves the radiation of the microstrip antenna.

Spreading remote lab usage a system — A community — A Federation

Experiments have been at the heart of scientific development and education for centuries. From the outburst of Information and Communication Technologies, virtual and remote labs have added to hands-on labs a new conception of practical experience, especially in Science, Technology, Engineering and Mathematics education. This paper aims at describing the features of a remote lab named Virtual Instruments System in Reality, embedded in a community of practice and forming the spearhead of a federation of remote labs. More particularly, it discusses the advantages and disadvantages of remote labs over virtual labs as regards to scalability constraints and development and maintenance costs. Finally, it describes an actual implementation in an international community of practice of engineering schools forming the embryo of a first world wide federation of Virtual Instruments System in Reality nodes, under the framework of a project funded by the Erasmus+ Program.

Fuzzy-based opportunistic power control strategy in cognitive radio networks

This paper considers the spectrum sharing network consisting of a pair of primary users (PUs) and a pair of cognitive users (CRs) in a fading channel. The pair of PUs establishes a wireless link as the PU link. The pair of CRs establishes a wireless link as the CR link. The PU link and CR link utilize spectrum simultaneously with different priorities. The PU link has a higher priority to utilize spectrum with respect to the CR link. When the PU link utilizes spectrum, a desired quality of service (QoS) is given to be assured and the CR utilizes spectrum with an opportunistic power scale under this constraint, assuring the desired QoS on the PU link. To compute an optimal opportunistic power scale for the CR link, a fuzzy-based opportunistic power control strategy is proposed based on the Mamdani fuzzy control model using two input variables: the PUs SNR and PUs interference channel gain. By the proposed fuzzy-based power control strategy, the desired QoS could be assured on the PU link and the bit error rate (BER) is also reduced compared with the spectrum sharing network without power control strategy.

An in-situ real time impulse response auto-test of resistance temperature sensors

A new method for achieving an automated in-situ impulse response test of resistance temperature sensors is described in this paper. An implementation of the automated in-situ test and some experimental results are also given. The experimental setup is based on a signal processor board programmable directly from Matlab and Simulink. The suggested test can be built into the sensor system giving an intelligent or smart sensor.

Using the Fingerprinting Method to Customize RTLS Based on the AoA Ranging Technique

Real-time Locating Systems (RTLSs) have the ability to precisely locate the position of things and people in real time. They are needed for security and emergency applications, but also for healthcare and home care appliances. The research aims for developing an analytical method to customize RTLSs, in order to improve localization performance in terms of precision. The proposed method is based on Angle of Arrival (AoA), a ranging technique and fingerprinting method along with an analytically defined uncertainty of AoA, and a localization uncertainty map. The presented solution includes three main concerns: geometry of indoor space, RTLS arrangement, and a statistical approach to localization precision of a pair of location sensors using an AoA signal. An evaluation of the implementation of the customized RTLS validates the analytical model of the fingerprinting map. The results of simulations and physical experiments verify the proposed method. The research confirms that the analytically established fingerprint map is the valid representation of RTLS’ performance in terms of precision. Furthermore, the research demonstrates an impact of workspace geometry and workspace layout onto the RTLS’ performance. Moreover, the studies show how the size and shape of a workspace and the placement of the calibration point affect the fingerprint map. Withal, the performance investigation defines the most effective arrangement of location sensors and its influence on localization precision.

Switched Kalman filter in a high frequency series loaded resonant converter

A switched power converter is a hybrid system and can be modelled by a switched linear model consisting of a set of linear differential equations and connected logic conditions. If the time instants of the switching are known the system can be viewed as a linear time varying system. A switched Kalman filter is developed to meet the switched property and enable a state feedback control. The filter is tested in a high frequency resonant power converter. The filter is developed in a system for rapid prototyping of filter and control algorithms.

Customization of UWB 3D-RTLS Based on the New Uncertainty Model of the AoA Ranging Technique

The increased potential and effectiveness of Real-time Locating Systems (RTLSs) substantially influence their application spectrum. They are widely used, inter alia, in the industrial sector, healthcare, home care, and in logistic and security applications. The research aims to develop an analytical method to customize UWB-based RTLS, in order to improve their localization performance in terms of accuracy and precision. The analytical uncertainty model of Angle of Arrival (AoA) localization in a 3D indoor space, which is the foundation of the customization concept, is established in a working environment. Additionally, a suitable angular-based 3D localization algorithm is introduced. The paper investigates the following issues: the influence of the proposed correction vector on the localization accuracy; the impact of the system’s configuration and LS’s relative deployment on the localization precision distribution map. The advantages of the method are verified by comparing them with a reference commercial RTLS localization engine. The results of simulations and physical experiments prove the value of the proposed customization method. The research confirms that the analytical uncertainty model is the valid representation of RTLS’ localization uncertainty in terms of accuracy and precision and can be useful for its performance improvement. The research shows, that the Angle of Arrival localization in a 3D indoor space applying the simple angular-based localization algorithm and correction vector improves of localization accuracy and precision in a way that the system challenges the reference hardware advanced localization engine. Moreover, the research guides the deployment of location sensors to enhance the localization precision.