An Analogy Principle in Inductive Logic

We propose an Analogy Principle in the context of Unary Inductive Logic and characterize the probability functions which satisfy it. In particular in the case of a language with just two predicates the probability functions satisfying this principle correspond to solutions of Skyrms? ‘Wheel of Fortune’.     

An Oligopolistic Investment Model of the Finnish Electricity Market

The investment problem faced by producers in deregulated electricity markets contains high uncertainties about the future. It can also be seen as a game, as only a small number of large players act in the market. A dynamic stochastic oligopoly model to describe the production and investment in such a situation is developed and applied to the Finnish electricity market. The demand growth rate is modeled as a stochastic variable. The strategies of the firms consist of investments and production levels for base and peak load periods. The firms have nuclear, hydro and thermal capacities, but are only allowed to invest in new thermal capacity. Using a so-called sample-path adapted open-loop information structure, the model contributes to the understanding of the dynamics of production, investment and market power in a medium time horizon. The solution method uses recent developments in variational inequality and mixed complementarity problem formulations.     

The Logic of Analogy

How should a scientist argue when the data are insufficient to allow him to reason by classical or statistical models? After all, in most real world situations - in business or in war - that is the unhappy norm. In such cases the ordinary man instinctively argues by analogy, as Leibniz long ago showed; indeed if time presses, there is no alternative. The trouble, however, is that if we then include such arguments in our scientific reasoning, then, as we all know, this can lead to false conclusions. To escape from this dilemma, is there any alternative logical basis from which we can start our reasoning? What is proposed here is that instead of the well tried three valued logic of true, false or probable, we should adopt the three valued logic of true, false or possible. A rational system for analogue arguments can then be developed by these means, and with it the advantages brought by the use of symbols and so on. Such a method, however, includes many necessary changes as to how to structure our problems and how to apply new criteria; and it is some of these changes that are outlined in this note. For instance, it outlines the meaning of ‘causal relationships’ in analogue arguments, as well as how to define ‘rational choice’ in terms of analogue propositions. The advantage throughout is that this allows us to argue with less rather than more data.     

等直弹性杆自由扭转电涡流比拟

本文提出了测定弹性等截面直杆自由扭转剪应力和抗扭刚度的一种新的比拟理论和方法——电涡流比拟。在理论部分建立了电涡流和自由扭转的比拟关系。在实验部分依照比拟理论设计了试验装置和测量线路;并通过对某些具有解析解的截面形状进行了实际测量,所得实验数据验证了本理论的正确性;还对集肤效应和影响精度的一些主要因素进行了讨论。本文所得结果可以推广到其它类似的流场或者具有一定边界条件的泊松方程(或拉普拉斯方程)求解。     

电力市场中合同电量与竞争电量交易比例的研究

在单边开放的区域电力市场中,合理的合同电量与竞争电量交易比例是保证电力市场有效运行的一个重要环节。竞争电量所占的比例将主要取决于当前发电公司的市场行为。首先使用BP神经网络对电力需求弹性系数进行了预测,然后以长期电力市场均衡为目标函数,考虑贵州电网发电机组的可用容量与负荷预测的误差,以及贵州输电线路的可靠性诸因素,推导出合同电量与竞争电量交易比例,经过与南方区域电力市场目前运营规则规定的交易比例比较,该比例是合理的,可以规避电力市场价格波动等带来的风险。     

一种电力变压器铁芯柱截面优化设计的模型

首先分析了电力变压器铁心柱制造的特点,以铁心柱外接圆为650毫米时建立了非线性的数学规划模型.并用Lingo10.0软件求解了该模型,从而得到了电力变压器铁心柱截面的优化设计方案,方案有模型简单和计算速度快等特点.     

Electricity swing options: Behavioral models and pricing

Electricity swing options are supply contracts for power, which give the owner the right to change the required delivery on short time notice. It gives more flexibility than fixed base load or peak load contracts. The name “option” is a bit misleading, since it gives the owner multiple exercise rights at many different time horizons with exercise amounts on a continuous scale. We look at the problem to determine a rational ask price for such a contract from the viewpoint of the contract seller. The pricing of these contracts differs drastically from the pricing of financial options. First, peculiar properties arise from the non-storability of the underlying (the energy) and therefore the impossibility to hedge with the underlying, hedging is only possible with some future contracts. Second, the behavior of the owner plays an important role. Based on some behavioral model for the option holder, we develop a game-theoretic model, which allows to identify the equilibrium price. Besides some theoretical results, we present some numerical results which clarify the dependence of the asked price on the amount of flexibility offered in the swing option.     

An Integrated Market for Electricity and Natural Gas Systems with Stochastic Power Producers

In energy systems with high shares of weather-driven renewable power sources, gas-fired power plants can serve as a back-up technology to ensure security of supply and provide short-term flexibility. Therefore, a tighter coordination between electricity and natural gas networks is foreseen. In this work, we examine different levels of coordination in terms of system integration and time coupling of trading floors. We propose an integrated operational model for electricity and natural gas systems under uncertain power supply by applying two-stage stochastic programming. This formulation co-optimizes day-ahead and real-time dispatch of both energy systems and aims at minimizing the total expected cost. Additionally, two deterministic models, one of an integrated energy system and one that treats the two systems independently, are presented. We utilize a formulation that considers the linepack of the natural gas system, while it results in a tractable mixed-integer linear programming (MILP) model. Our analysis demonstrates the effectiveness of the proposed model in accommodating high shares of renewables and the importance of proper natural gas system modeling in short-term operations to reveal valuable flexibility of the natural gas system. Moreover, we identify the coordination parameters between the two markets and show their impact on the system’s operation and dispatch.     

可再生能源价格政策在寡头竞争市场中的比较

在考虑可再生能源发电间歇性和电力企业两阶段决策过程的前提下,建立了度电补贴和配额制政策下的电力市场寡头垄断竞争模型并进行了分析。以以色列电力市场的数据进行数值实验,分析了电力企业数量、补贴价格、可再生能源电力配额、投资费用等关键因素对发电容量投资的影响。考虑到政策的福利效应,比较了度电补贴和配额制政策下电力价格、消费者剩余和社会福利的差异。     

Determining the Optimal Reserve Capacity Margin in Electricity Supply: A Note

The operational reserve capacity margin in electricity is usually determined on the basis of engineering considerations and past experience. The economic theory for optimal pricing offers certain rules for deciding about capacity margins, but the underlying assumptions are strong and restrictive. This paper attempts to determine the optimal reserve capacity margin according to the relative costs, to the firm and to society, of supply shortages. It takes into account the difference between capacity and energy costs and quantifies their impact on the capacity margin.     

Learning Electricity with NIELS: Thinking with Electrons and Thinking in Levels

Electricity is regarded as one of the most challenging topics for students of all ages. Several researchers have suggested that na?ve misconceptions about electricity stem from a deep incommensurability (Slotta and Chi 2006; Chi 2005) or incompatibility (Chi et al. 1994) between na?ve and expert knowledge structures. In this paper we argue that adopting an emergent levels-based perspective as proposed by Wilensky and Resnick (1999), allows us to reconceive commonly noted misconceptions in electricity as behavioral evidences of “slippage between levels,” i.e., these misconceptions appear when otherwise productive knowledge elements are sometimes activated inappropriately due to certain macro-level phenomenological cues only. We then introduce NIELS (NetLogo Investigations In Electromagnetism), a curriculum of emergent multi-agent-based computational models. NIELS models represent phenomena such as electric current and resistance as emergent from simple, body-syntonic interactions between electrons and other charges in a circuit. We discuss results from a pilot implementation of NIELS in an undergraduate physics course, that highlight the ability of an emergent levels-based approach to provide students with a deep, expert-like understanding of the relevant phenomena by bootstrapping, rather than discarding their existing repertoire of intuitive knowledge.

Short-Term Forecasting: A Review of Procedures in the Electricity Supply Industry

A review of forecasting procedures which have been developed in the electricity supply industry to serve the short-term needs of load dispatching is presented. The procedures are broadly categorised into whether or not use is made of a standard load concept. From the point of view of comparative research in applied forecasting, some comments are proposed on the wide variety of methods which have been developed for basically similar problems.     

交易成本型证券投资中求最优投资方案的一个算法

给出一个交易成本型证券投资中求最优投资方案的数值算法 ,证明了算法的理论依据 ,并举例说明算法的应用 .