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

In this paper, a laboratory experiment was conducted to compare the performance of lightning discharge characteristics of bare conductor (BC) and covered conductor (CC), resulting from very-close lightning strokes to trees. Special attention is paid to the influence of rainfall on the lightning arc characteristics. All the experiments are performed using full-scale configurations. Other factor investigated is the effects of tree-to-line clearance. The studies reveal a substantial amount of new information which is required to fully understand the true behavior of very-close lightning interaction with power conductors in rainfall, which is often the true lightning situation.

Influence of rainfall on lightning flashovers from trees to medium voltage bare and covered conductors

The effect of network compensation on the transient recovery voltage during earth faults on medium voltage networks

Photovoltaic hosting capacity improvement based on the economic comparison between curtailment and network upgrade

The global interest in increasing photovoltaic (PV) hosting capacity has lately grown. This research focuses on introducing a unique stochastic strategy that can optimize the hosting capacity of PV in modern distribution networks. The suggested strategy is based on combined control techniques of practical control devices, such as taps of transformers as well as reactive power sources. It also takes into account the distributed electrical vehicles (EVs) with their stochastic model and full features of their batteries. Furthermore, the PV planning model takes into account the reactive power provided by the PV inverter. The PV planning model is solved by a developed bi-layer grey wolf optimizer. The optimizer–s inner layer adjusts the charging/discharging power of the interconnected EV batteries, transformer taps, besides reactive power injection. In turn, the outer layer maximizes PV capacities. Many scenarios are run on an IEEE distribution system to evaluate the efficacy of the suggested planning strategy of multiple PVs with EVs. The suggested method has the ability to enhance the PV hosting capacity at a significant rate while properly the various practical control devices in a corresponding way.

On Maximizing PV Hosting Capacity in Modern Distribution Networks Based on Diverse Control Techniques

Electric vehicles (EVs) have experienced an unprecedented increase in their penetration; in well developed countries; due to the advancement of battery technology and the need to make transportation more environmentally friendly. As a result of this trend, EVs have become an integral part of those countries power grid ecosystem, where they may be used as both a source, and a consumer of energy. However, cybersecurity risks associated with large fleets of EVs within the power grids can significantly impact the normal operation of distribution systems. This paper considers the cyber-attack consequences, from attackers’ perspective. The cyber attackers under study target the charging price (CP) by increasing the CP in off-peak hours and accordingly subsiding it in on-peak hours. A two-stage optimization framework is proposed to identify the most important ultra-fast charging stations (XFCs) under the cyber-attack, meanwhile, the EV users’ response to the compromised CP is considered. Then, the proposed model is implemented on a modified IEEE 123-bus distribution test system, and the effectiveness of the model is proved through some case studies. In particular, they demonstrated that the amount of load shedding is increased by 8.198 MW when the EV user response is taken into account.

Matti Lehtonen

Papers

Influence of rainfall on lightning flashovers from trees to medium voltage bare and covered conductors

The effect of network compensation on the transient recovery voltage during earth faults on medium voltage networks

Photovoltaic hosting capacity improvement based on the economic comparison between curtailment and network upgrade

On Maximizing PV Hosting Capacity in Modern Distribution Networks Based on Diverse Control Techniques

Vulnerability of EV Charging Stations to Cyber Attacks Manipulating Prices