There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

THE DESIGN AND ANALYSIS OF EXPERIMENTS. By Oscar Kempthorne. New York, John Wiley and Sons, Inc., 1952. 631 pp. $8.50. This book by a teacher of statistics (as well as a consultant for \"experimenters\") is a comprehensive study of the philosophical background for the statistical design of experiment. It is necessary to have some facility with algebraic notation and manipulation to be able to use the volume intelligently. The problems are presented from the theoretical point of view, without such practical examples as would be helpful for those not acquainted with mathematics. The mathematical justification for the techniques is given. As a somewhat advanced treatment of the design and analysis of experiments, this volume will be interesting and helpful for many who approach statistics theoretically as well as practically. With emphasis on the \"why,\" and with description given broadly, the author relates the subject matter to the general theory of statistics and to the general problem of experimental inference. MARGARET J. ROBERTSON

The Design and Analysis of Experiments

[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

This review focuses on inverter technologies for connecting photovoltaic (PV) modules to a single-phase grid. The inverters are categorized into four classifications: 1) the number of power processing stages in cascade; 2) the type of power decoupling between the PV module(s) and the single-phase grid; 3) whether they utilizes a transformer (either line or high frequency) or not; and 4) the type of grid-connected power stage. Various inverter topologies are presented, compared, and evaluated against demands, lifetime, component ratings, and cost. Finally, some of the topologies are pointed out as the best candidates for either single PV module or multiple PV module applications.

A review of single-phase grid-connected inverters for photovoltaic modules

In this paper, a three-level hybrid boost converter with output voltage regulation and capacitor balancing is presented The converter is developed based on the single-phase three-level T-type neut

Three-Level Hybrid Boost Converter with Output Voltage Regulation and Capacitor Balancing

The conventional contact type brake system which uses a hydraulic system has many problems such as time delay response due to pressure build-up, brake pad wear due to contact movement, bulky size, and low braking performance in a high speed region. As vehicle speed increases, a more powerful brake system is required to ensure vehicle safety and its reliability. In this work, a contact less brake system using a magnetorheological is proposed to overcome the problems. A magnetic fluid changes its properties (viscosity) under the influence of an external magnetic field. This effect is the result of changes in the fluid structure: the ferromagnetic particles of the fluid, being single domains, when subjected to an external magnetic field, become orientated and concentrated along the lines of forces of the magnetic Field. The design of the electromechanical converters mentioned above permits the space between the casing and the moving component of the converter to be filled with the magnetorheological fluid. A coil supplied with power is placed on the moving component of the converter or inside the casing, depending magnetorheological fluid enable to change the parameters of a mechanic system (rigidity, braking force) as a result of electric voltage and current control.

Development of fuzzy logic controller for magnetorheological rotary brake system

This paper presents a simple modulation technique that minimizes the output voltage total harmonic distortion (THD) without eliminating the lowest order harmonics. It uses the voltage-angle equal concept of sinusoidal reference waveform to generate the step output voltage of a single-phase transistor-clamped H-bridge (TCHB)-based cascaded multilevel inverter. The real implementation of the modulation technique for a various range of modulation indices is built using an Altera field-programmable gate array (FPGA). It is found that the proposed modulation method resulted in a dramatic decrease in the inverter’s output voltage THD when increasing the number of output steps up to thirteen levels.

A Simple THD Minimization Technique for Transistor-Clamped H-Bridge-Based Cascaded Multilevel Inverter

This paper demonstrates the monitoring of EMI and total harmonic distortion that are generated in a UPS system on no load and full load conditions. This paper concentrates on the relation between the UPS parameters.

EMI filters performance monitoring

In this paper, a simple and fast open-phase fault (OPF) detection and fault tolerant control method is proposed for three-phase induction machine. Instead of using integrators or low pass filter, this method utilizes the phase current magnitude and trajectory to detect open phase fault in three-phase motor drive. This significantly increases the speed of fault detection, allowing an OPF to be detected and compensated within several sampling cycles, which is advantageous for safety-critical applications. In addition, a double synchronous reference frame PI (DSRF-PI) controller method is adopted as the fault tolerant controller. Compared to previous methods that utilizes feedforward voltage compensation, the DSRF-PI does not require prior knowledge on the machine parameters and operating condition, and therefore is easier to implement. The proposed fault detection and fault tolerant control method are simulated using MATLAB Simulink simulation where the results confirms the high speed and robustness of the proposed methods.

Nasrudin Abd Rahim

Papers

Three-Level Hybrid Boost Converter with Output Voltage Regulation and Capacitor Balancing

Development of fuzzy logic controller for magnetorheological rotary brake system

A Simple THD Minimization Technique for Transistor-Clamped H-Bridge-Based Cascaded Multilevel Inverter

EMI filters performance monitoring

Current Trajectory-Based Fault Detection and Fault Tolerant Control for Three-phase Induction Drives