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

This paper proposes an optimal voltage regulation scheme (OVRS) for distribution systems with rich photovoltaic (PV). Various regulation devices are optimally controlled in a coordinated manner: PV...

Optimal Voltage Regulation Scheme for PV-Rich Distribution Systems Interconnected with D-STATCOM

Measured voltage sag distributions

Outage costs in electrical distribution networks - a Finnish study

With the increase in distributed generation, the demand-only nature of many secondary substation nodes in medium voltage networks is becoming a mix of temporally varying consumption and generation with significant stochastic components. Traditional planning, however, has often assumed that the maximum demands of all connected substations are fully coincident, and in cases where there is local generation, the conditions of maximum consumption and minimum generation, and maximum generation and minimum consumption are checked, again assuming unity coincidence. Statistical modelling is used in this paper to produce network solutions that optimize investment, running and interruption costs, assessed from a societal perspective. The decoupled utilization of expected consumption profiles and stochastic generation models enables a more detailed estimation of the driving parameters using the Monte Carlo simulation method. A planning algorithm that optimally places backup connections and three layers of switching has, for real-scale distribution networks, to make millions of iterations within iterations to form a solution, and therefore cannot computationally afford millions of parallel load flows in each iteration. The interface that decouples the full statistical modelling of the combinatorial challenge of prosumer nodes with such a planning algorithm is the main offering of this paper.

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Probabilistic prosumer node modeling for estimating planning parameters in distribution networks with renewable energy sources

Electric vehicle (EV) charging is expected to constitute a substantial part of the power demand in residential areas in the future. Its effects on the principles of distribution network planning and load profiles need to be studied. In this paper, we evaluate the feasibility of replacing the conventional cars with EVs in Finnish district heated apartment house areas. Stochastic simulation is used to combine a probabilistic charging model and electricity consumption data. We estimate the effects of uncontrolled, curtailed and price-optimized residential EV charging with different charging powers defined in the standards. The simulation results show that with 11.1 kW and 22.2 kW uncontrolled charging, the example apartment house connections would be overloaded. It is also found that the price-optimized charging should include a coordinated control logic that supports the local grid. With 1.84 kW charging, the power demand stays within the acceptable limits, but the coincidence factor increases from 0.2 to 0.63-0.93.

Matti Lehtonen

Papers

Optimal Voltage Regulation Scheme for PV-Rich Distribution Systems Interconnected with D-STATCOM

Measured voltage sag distributions

Outage costs in electrical distribution networks - a Finnish study

Probabilistic prosumer node modeling for estimating planning parameters in distribution networks with renewable energy sources

Electric Vehicle Charging Loads in Residential Areas of Apartment Houses