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

Characteristics of Wireless Sensors for Electrical Distribution Networks

A Simple Transient-Based Wide-Area Selectivity Technique for Earth-Faults in Isolated and Compensated Neutral Medium Voltage Networks

SUMMARY

This paper addresses the modification of the existing dynamic arc model for lightning arc simulation application. The modified dynamic arc model combines the static and the dynamic arc equations that are already established in the literature to reproduce an arc fault involving a lightning-struck tree and a nearby power distribution line during rainfall. The results of experimental studies regarding arc creation between a tree and a nearby power line with artificial rainfall were obtained. A complete model of this phenomenon is reproduced using the electromagnetic transient program (ATP/EMTP) and the existing static and dynamic arc equations. The essential reason for modifying this model is graphically shown with a comparison of the dynamic arc and the modified dynamic arc models. The performance of the arc phenomenon was examined using a typical Finnish distribution network design. By means of simulation using the modified dynamic arc, developed within the ATP/EMTP software with its Transient Analysis Control System features, the lightning arc performance of the MV/LV network under the influence of nearby trees and the network characteristics is analyzed. It is expected that such a model can be included in the existing ATP/EMTP software packages for simulating power system transients. Copyright © 2011 John Wiley & Sons, Ltd.

Modelling and evaluation of the lightning arc between a power line and a nearby tree

The role of EV based peer-to-peer transactive energy hubs in distribution network optimization

-The main goal of this paper is to investigate the impact of the network type and configuration on the transient behavior of the fault and neutral points during an earth fault. Studying both neutral and fault points enables us to understand clearly the network behavior. The investigations cover the effect of the network type including, feeder types: overhead line and mixed overhead and cable networks with different neutral earthing conditions: unearthed (isolated) or compensated neutral networks. The investigations focused on the transient behavior of the fault point (fault current and voltage) and neutral point voltage. A mathematical simulation model based on a realistic network is implemented using the transient simulation program ATP/EMTP. The effect of the capacitive response of cables in mixed networks has been investigated and presented. On the other hand, the interaction with a compensation coil has been highlighted as well.

Matti Lehtonen

Papers

Characteristics of Wireless Sensors for Electrical Distribution Networks

A Simple Transient-Based Wide-Area Selectivity Technique for Earth-Faults in Isolated and Compensated Neutral Medium Voltage Networks

Modelling and evaluation of the lightning arc between a power line and a nearby tree

The role of EV based peer-to-peer transactive energy hubs in distribution network optimization

The impact of the distribution network type and configuration on the transient behavior of the fault and neutral points during earth faults