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

With continually increasing emphasis on the reliability of power systems, further understanding of the main causes of lightning faults in medium voltage lines is required for effective protection Lightning-induced voltage on power distribution lines or telecommunication lines has been a subject that has received critical attention in the literature for years However, very few investigations have been carried out on the influence of very close and tall structures, such as trees, buildings and other high structures on the lightning performance of power distribution lines Recent measurements have revealed that a tree can intersect a lightning stroke in the vicinity of a power line, but not in all situations In addition, induced voltage exists even when the power line is perfectly shielded by the nearby tree This paper presents the results of experimental findings on the induced voltages existing between a lightning-struck tree and a power distribution line The effects of; tree-to-line clearance, change in lightning time characteristics and polarities on the induced voltages are investigated

Experimental performance of induced voltage on power line due to lightning discharge to nearby tree

A method that utilises a customer voltage density function for distribution system voltage monitoring and control is presented. The novelty of the method is, that the voltage received by the customers is directly used for voltage quality assessing and for control optimization. The information needed for the method is the voltage magnitude at all the customer connection points over the network area considered. This voltage magnitude can be obtained through distribution system state estimation and increasingly, in the future, by direct measurements. The voltage control can be optimised if the price of too low or too high a voltage level is known. For this purpose a penalty function is proposed. When integrating this penalty function over the customer voltage density function, the total penalty of a control alternative can be produced, and hence different control alternatives can be compared. supplied by a given low voltage distribution transformer. The analysis and comparison of these density functions also opens new possibilies for the control and optimization of the distribution network voltage. In this presentation, the accepted customer voltage levels are first discussed. The computation of the voltage density function is presented, and the main factors affecting the voltage levels are analysed. For the estimation of the voltage level value, a penalty function is presented. Finally, the usage of the voltage density function in optimizing the voltage control of a distribution area is outlined.

Customer voltage density function in distribution system voltage monitoring and control

Novel accurate modeling of dust loaded wire-duct precipitators using FDM-FMG method on one fine computational domains

A partial discharge detection concept for wireless sensors in covered conductor distribution system

This paper presents a method for using the most accurate available geographic data in network topology planning. The process is an iterative process, where an initial network topology is first generated in order to acquire certain topology related parameters for each node-to-node connection. Then, node-to-node optimal routes are considered through individual cost surfaces, generated with varying topological and static geographic inputs. A near-optimal network topology is then constructed, now also considering the geographical cost drivers and constraints. In the topology the back-up connections and network sectionalization devices are also considered from the point of view of cost-optimality. A study from a real network proves the potential of the developed methodology to be able to cope with realistically sized networks

Matti Lehtonen

Papers

Experimental performance of induced voltage on power line due to lightning discharge to nearby tree

Customer voltage density function in distribution system voltage monitoring and control

Novel accurate modeling of dust loaded wire-duct precipitators using FDM-FMG method on one fine computational domains

A partial discharge detection concept for wireless sensors in covered conductor distribution system

Distribution Network Topology Planning Using Life Cycle Cost driven Cost Surfaces in the Internodal Parameter Computation