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

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

计量经济分析 = Econometric analysis

This chapter discusses leading problems linked to energy that the world is now confronting and to propose some ideas concerning possible solutions. Oil deserves special attention among all energy sources. Since the beginning of 1981, it has merely been continuing and enhancing the downward movement in consumption and prices caused by excessive rises, especially for light crudes such as those from Africa, and the slowing down of worldwide economic growth. Densely-populated oil-producing countries need to produce to live, to pay for their food and their equipment. If the economic growth of the industrialized countries were to be 4%, even if investment in the rational use of energy were pushed to the limit and the development of nonpetroleum energy sources were also pursued actively, it would be extremely difficult to prevent a sharp rise in prices. It is evident that it is absolutely necessary to pursue actively the development of coal, natural gas, and nuclear power if a physical shortage of energy is not to block economic growth.

World energy outlook

Introduction to stochastic programming

The practical implementation of traveling wave fault location depends on the transducer characteristics at high frequency transients as a result of faults and other disturbances In this paper, an experimental study of the current transformer parameters at high frequencies has been carried out. Transfer function has been investigated and calculated. CT parameters have been measured using different methods. The frequency response of the CT has been calculated over a wide range of frequency.

Effect of Current Transformer Transient Models on the Detection of Traveling Waves

Accurate arcing fault location can be realized via wideband electromagnetic signal radiations from the arc source point. An overview of several existing literatures devoted to power arcing fault source location suggests some approaches which are as follows: Directional Finding method (DF), Angle of Arrival method (AoA), Time difference of Arrival (TDOA) method and Propagation Attenuation (PA) method. In this paper the joint TDOA and AoA is used to locate power arcing source point through real data measurement. The measurement principle is based on four strategically placed directional finding antennas to gather power arc electromagnetic signals radiations. Using the arc signals time difference of arrival at each antenna, the signals’ angles of arrival and TDOA are derived; subsequently the power arc source position is pin-pointed. The results show that the proposed algorithm works with as reasonable accuracy as other conventional methods. This proposed method could be used as a new adaptive solution for estimating efficiently the power arcing fault source position by integrating it to the distribution management system (DMS) and/or outage Management system (OMS) for accurate location of fault arcs, faster power supply restoration and minimized outage hours under real field conditions.

Arcing faults localization using RF-signal angle of arrival method

This paper aims to quantitatively evaluate and compare the reliability impact of employing an automatic loop restoration scheme in a typical distribution system, with and without pulse closing technology. Sustained interruptions, momentary interruptions and voltage sags are the three major attributes of the service reliability that are taken into account in the reliability case studies. (4 pages)

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Application of pulse closing technology for automatic loop restoration

In the retrofitting of older buildings with central heating into nearly zero-energy buildings more and more air to water heat pumps are used. These heat pumps are normally connected to heating systems, producing heat only on demand. The greatest demand for heat occurs when the outside temperature and therefore the COP of the pump is lowest. Outside temperature varies during the day, meaning it is possible to save energy by producing and storing heat in a situation where the COP is higher. To determine the periods with higher COP values weather forecast data and COP curves are used. The data enables to rank and select time periods for heat production. This in conjunction with the heat demand curve of the building enables to create an operation schedule for the heat pump. The aim of the study is to develop heat pump control methods for renovated buildings to comply with nearly zero energy building codes. Dependant on the heat pump and weather conditions, up to 10% of the electricity demand for heating can be decreased.

Matti Lehtonen

Papers

Effect of Current Transformer Transient Models on the Detection of Traveling Waves

Arcing faults localization using RF-signal angle of arrival method

Application of pulse closing technology for automatic loop restoration

A control method for increasing the heat usage efficiency of nearly-zero-energy buildings with heat pumps

Interactive web-based guideline for the efficiency of household electric power consumption