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

This paper presents a new approach for harmonic control, and its practical implementation for a single-phase hybrid active power filter. It is a combination of a series active power filter and a shunt passive filter. The shunt passive filter is connected in parallel with a load and suppresses the harmonic current produced by the load, whereas the active filter connected in series to a source acts as a harmonic isolator between the source and load. For active filter control, sinusoidal pulse width modulation (SPWM) is developed and the modulation index is selected by calculating the DC bus voltage of the active filter. The PSpicereg, Matlab/Simulinkreg and MAX PLUS IIreg softwares are used for simulation and hardware implementation. ALTERAreg FLEX 10K controller and some peripheral circuits are used. Simulation and experimental results show that the proposed active power filter topology is capable of compensating the load current and voltage harmonic up-to the limit specified by IEC.

A New Approach for Harmonic Compensation Using Single- phase Hybrid Active Power Filter

Fuzzy logic is recognized as an intelligent approach to complex problems demanding fulfillment of several criteria. A smart solution for an elevator group control system is one complex problem. This paper discusses a fuzzy logic dispatching strategy for elevator group control that uses a self-tuning fuzzy logic controller to tune membership functions and adjust fuzzy rule sets. Computer simulation evaluates, in three traffic peaks, the strategypsilas effectiveness. The results, when compared with other strategies that use conventional controllers, show considerable overall improvements in both waiting time and riding time.

Self-tuning fuzzy-based dispatching strategy for elevator group control systems

The paper proposes and describes the design and operating principles of 5 levels voltage source inverter which acts as a link between the output of the linear generator and the load. The output frequency of the linear generator varies from 25 to 50 Hz depending on the load. Due to that, it is not suitable for many applications, which use 50 Hz ac. This inverter consists of 6 switches (two levels conventional inverter) which operate at the main line power frequency besides an auxiliary circuit consists of three switches and with one diode in series with one diode. This auxiliary circuit operates also at the line power frequency and as be shown later it acts as an active filter in reducing the harmonic contents of the output waveform. A prototype has been designed and implemented. To asses the proposed inverter, it is compared with the conventional two level inverter with single switching inverter. Simulation and experimental results are provided to verify the validity of the model

Proposed Nine Switches Five Level Inverter With Low Switching Frequencies for Linear Generator Applications

A techno-environmental assessment of hybrid photovoltaic-thermal based combined heat and power system on a residential home

In this paper, dynamic simulation of a fuel cell system studied using MATLAB/SIMULINK. The paper presents the dynamic model of proton exchange membrane fuel cell (PEMFC). The fuel cell output voltage is proportional to the change of the current drawn from the fuel cell model. Phase control full bridge dc/dc converter considered to match the unregulated voltage produced by the fuel cell model to the needed application voltage. PID controller has been selected to regulate the fuel cell output voltage. PWM-based inverter serves as the interface between the dc/dc converter and the ac load. Three-phase inverter used to drive three phase load. Third harmonic injection pulse width modulation used to drive the three-phase inverter so that minimum harmonic distortion and maximum usage of the fuel cell voltage on the three-phase inverter output. Simulation results provided to validate the design.

Nasrudin Abd Rahim

Papers

A New Approach for Harmonic Compensation Using Single- phase Hybrid Active Power Filter

Self-tuning fuzzy-based dispatching strategy for elevator group control systems

Proposed Nine Switches Five Level Inverter With Low Switching Frequencies for Linear Generator Applications

A techno-environmental assessment of hybrid photovoltaic-thermal based combined heat and power system on a residential home

Dynamic and control of fuel cell system