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

Recent works in ubiquitous computing have addressed analysis of electric power for energy conservation by detailing and studying consumption of electrical appliances. We contribute with an approach to develop techniques for fingerprinting and monitoring consumption of electric power in households. The approach builds on previous works and employs three phases: feature extraction of attributes such as real power and current harmonic contents, event detection and pattern recognition. A load library is foreseen that stores appliance characteristics as corpus data for training and recognition. We report early findings achieved using a high definition sensor directly applied to the loads showing promising results but also challenges in event detection (smaller state transitions, challenges in detecting and pairing switch on and off events). These studies are important in order to be able to address opportunities of identifying and monitoring directly at the appliance level or sensing the total load of the network. Future applications include monitoring and detailing of loads in a “balance sheet” and context aware service with advice tips for energy users. Keywordsubiquitous computing; load monitoring; fingerprinting; pattern recognition; energy awareness

Exploring Techniques for Monitoring Electric Power Consumption in Households

Optimizing the DR Control of Electric Storage Space Heating Using LP Approach

Estimating the customer interruption costs is a challenge for the electric power society. In this paper the results of a customer survey on power outage costs for industry sectors conducted in Finland have been presented. In addition, the problem of strategic responses has been investigated and an elimination method for the zero and extreme responses has been proposed. (4 pages)

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Evaluation of power outage costs for industrial sectors in Finland

Wind power plants are one of the most widespread sources of electric energy during the last few decades. Wind towers are quite often exposed to lightning strikes due to their tall height and long blades. In this paper, the lightning-induced voltages (LIVs) on a three-phase overhead line are computed for both first and subsequent strokes to a nearby grounded wind tower using the three-dimensional finite-difference time-domain method with homogeneous and horizontally stratified grounds. The horizontal electric fields are computed on the line and on the ground surface considering the transient grounding and characteristic impedances of the struck wind tower. The impact of the existence of wind tower on LIVs and horizontal electric fields is illustrated by removing the tower (i.e., return stroke to the ground surface). Finally, the influence of ground permittivity on the peak values of LIVs is investigated.

Induced Voltages on Overhead Line by Return Strokes to Grounded Wind Tower Considering Horizontally Stratified Ground

In the Nordic countries, most distribution networks are installed in forest areas. Direct strokes to a tree can cause severe damage to nearby power lines by initiating an arc channel through air to bare conductors. In this paper, this phenomenon is examined experimentally using a full-scale laboratory setup considering dry-air and wet-air conditions, and the experimental results were reproduced by computer simulations. In a number of the experimental runs performed, it was found that the conducting arc path allows the establishment of a large long-duration lightning current from the lightning-struck tree to the bare conductor under the wet-air condition. Consequently, a higher induced voltage is measured on the conductor. The lightning-triggered arc phenomenon was monitored closely. It was confirm that lightning strokes to a nearby tree can be more intense in the wet-air than in dry-air conditions, and cause a flashover on power lines. The ATP/EMTP computer simulation using the arc model shows that the experimental results, one of which has been photographed and reported in the paper, are reproducible by means of system modeling. Both the experimental and simulation results provide strong evidence confirming the phenomenon of the arc conduction and the induced voltages due to lightning strokes to nearby trees within the vicinity of power conductors. Using a Rusck model, the study is extended to evaluate the induced voltage from the tree to the power conductor for larger clearances.

Matti Lehtonen

Papers

Exploring Techniques for Monitoring Electric Power Consumption in Households

Optimizing the DR Control of Electric Storage Space Heating Using LP Approach

Evaluation of power outage costs for industrial sectors in Finland

Induced Voltages on Overhead Line by Return Strokes to Grounded Wind Tower Considering Horizontally Stratified Ground

Investigation of lightning arc between conductor and nearby tree under artificial rainfall