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

Cable Temperature Monitoring

The proliferation of photovoltaic (PV) has been increased in distribution systems worldwide. The intermittent PV generation can cause diverse operational problems in the grid, especially voltage deviations and violations. As a result, voltage assessment in distribution systems interconnected with PV, which has a heavy computational burden, is privileged to assist power utilities in decision-making. In this article, a low-computational and accurate voltage assessment approach with PV considering fine-resolution simulations (i.e., time-step of 1 s) is proposed. Specifically, the proposed approach can rapidly compute the voltage deviation in the whole distribution system and terminal voltages of PV units based on a data-driven model. This model is built using machine learning considering various scenarios of PV and load profiles. The proposed approach has the following features. 1) Its computational burden is very low compared to the widely used iterative-based methods. 2) It can handle the full data with the finest available resolution, yielding accurate voltage assessment. The proposed method has been applied for voltage assessment considering daily and annual simulations of different distribution systems interconnected with PV units. The simulation results manifest the high accuracy and computational speed of the proposed approach, especially for fine-resolution simulations.

Low-Computational Voltage-Assessment Approach Considering Fine-Resolution Simulations for Distribution Systems With Photovoltaics

In order to analyze the safety of nuclear power plants (NPP), interactions between thermomechanical and automation processes, the on-site electrical grid, and the off-site transmission system should be studied in detail However, an initial survey of simulation tools used for the modelling and simulation of NPP shows that existing simulation tools have some drawbacks in properly simulating the aforementioned interactions In fact, they simulate detailed electrical power systems and thermomechanical systems but neglect the detailed interactions of the electrical system with thermomechanical and automation processes To address this challenge, this paper develops an open-source co-simulation platform which connects Apros, a proprietary simulator of the thermomechanical and automation processes in NPP, to power system simulators The proposed platform provides an opportunity to simulate both the electrical and thermomechanical systems of an NPP simultaneously, and study the interactions between them without neglecting any details This detailed analysis can identify critical faults more accurately, and provides better support for probabilistic risk analyses (PRA) of NPP To investigate the effectiveness of the proposed platform, detailed thermomechanical and electrical models of an NPP, located in Finland, are cosimulated The preliminary results emphasize that neglecting the detailed interactions between domains of NPP may lead to inaccurate simulation results and may affect NPP safety

Electrical and Thermomechanical Co-Simulation Platform for NPP

Evaluating distribution network optimal structure with respect to solar hosting capacity

Generation of inverter-connected solar and wind power displaces kinetic energy in power systems, decreasing frequency quality and threatening the system security. As a solution, this paper investigates the potential of electricity consumption to increase the inertial response of the system so that the frequency quality is maintained. The study focuses on three types of consumption: Electric vehicle (EV) charging, direct electric space heating (DESH), and the consumption of refrigerators, which all have different characteristics in terms of their response to the power system frequency. We aim to assess their potential inertia contribution in a Finnish case study. Therefore, the study firstly introduces the consumption models with required load control strategies, after which the performance of the loads as a part of the Nordic power system frequency dynamics is simulated. The results indicate that the loads are able to contribute to the system inertia but their consumption may not coincide with the moments of low system kinetic energy.

Matti Lehtonen

Papers

Cable Temperature Monitoring

Low-Computational Voltage-Assessment Approach Considering Fine-Resolution Simulations for Distribution Systems With Photovoltaics

Electrical and Thermomechanical Co-Simulation Platform for NPP

Evaluating distribution network optimal structure with respect to solar hosting capacity

Electricity consumption contribution to power system inertia — Case electric vehicles and thermostatically controlled loads in Finland