Stationary policies

There are different classes of policies of interest, depending on which of the available information the decisions are based on. A policy can base decisions on all the information in the history of the process up to the time the decision is to be made. Such policies are called history-dependent policies. Given the memoryless nature of the transition probabilities, as well as the fact that the sets of feasible decisions and the expected rewards depend on the history of the process only through the current state, it seems intuitive that it should be sufficient to consider policies that base decisions only on the current state and time, and not on any additional information in the history of the process. Such policies are called memoryless, or Markovian, policies. If the transition probabilities, sets of feasible decisions, and rewards do not depend on the current time, then it also seems intuitive that it should be sufficient to consider policies that base decisions only on the current state, and not on any additional information in the history of the process or on the current time. (However, this intuition may be wrong, as shown by counterexample in Section 4.1.7). Under such policies, decisions are made in the same way each time the process is in the same state. Such policies are called stationary policies. 

Again motivated by the stationary input data, it is intuitive, and can be shown to be true, that the value function V of a stationary policy ir satisfies an equation similar to (37) for the finite horizon case, that is. 

Cachon and Zipkin (1990), we consider games where each player chooses a stationary policy the retailer s strategy is A and the wholesaler s strategy is order-up-to quantity Q, Three situations arise either the wholesaler or the retailer might have negotiation power in the supply chain and act as Stackelberg leaders, or it is possible that the players have equal power and therefore the solution is in the form of a Nash equilibrium. We will consider all three situations. 

Note that the objective function is concave, and hence the retailer s first-order condition characterizes the unique best response. For stationary policies, it is sufficient to consider the best response functions in the single-period game. The slope of the retailer s best-response function is found by implicit differentiation as follows ... 

Comparative analysis of the stationary policies Supply chain coordination... 

By the choice of the action space, all stationary policies have transition probability matrices representing recurrent aperiodic Markov chains. If the number of possible states is limited, i.e. if the one-period demand is bounded, we can determine the optimal production policy. The optimal policy can be determined by a policy iteration method, but we will use the method of successive iteration, as described by Odoni(1969), since this method is faster in our situation. The optimal policy is the policy which achieves the minimum expected costs per transition, which will be denoted by g. Defining the quantity v (r) as the total expected costs from the next n transitions if the current state is r and if an optimal policy is followed, the iteration scheme takes the form described in the optimality principle by Bellman (1957) ... 

Portable power and stationary or transport systems are validated infrastructure investment begins with governmental policies. 

The potential of stationary fuel cells for distributed generation depends on feed-in tariff policies and electricity and gas prices, as well as on market competition from gas engines and small turbines. SOFCs and MCFCs, mostly fuelled by natural gas, are likely to play an important role for combined heat and power generation in buildings. 

Krewitt, W., Nitsch, J., Fischedick, M., Pehnt, M. and Temming, H. (2006). Market perspectives of stationary fuel cells in a sustainable energy supply system - longterm scenarios for Germany. Energy Policy, 34 (2006), 793-803. 

Deals with issues that affect the quality of our air and protection from exposure to harmful radiation. OAR develops national programs, technical policies, and regulations for controlling air pollution and radiation exposure. Areas of concern to OAR include indoor and outdoor air quality, stationary and mobile sources of air pollution, radon, acid rain, stratospheric ozone depletion, radiation protection, and pollution prevention. 

A specific idea for analysis was voiced by a forum participant with a policy and industry perspective It might be helpful to a number of hydrogen interests and producers of technology products to see if we could do a definitive study on four or five specific stationary applications of hydrogen fuel cells that have a chance to compete cost-wise, and discover in what circumstances they could compete, so that people looking to market products in the near term have a better shot at meeting their targets. ... 

A primary consideration in the decision to deploy AFVs is that the justification and plan for the deployment of these vehicles must be part of an integrated national energy policy, which includes not only stationary sources, but also the entire range of energy use in the United States. 

A variety of different kinds of fuel cells are already commercially available in portable micro-electronic applications, as APUs and for stationary power. Whether they will become the dominant technology in any of these fields, and whether the FC concerned will use hydrogen or some other fuel, is still unclear. What is clear is that these applications in themselves offer few benefits beyond those to their private producers and users (though they may stimulate technological developments that have public benefits, such as FCVs). They are not likely to get significant support from public policy and will need to succeed in market terms. 

Hawkins, S., Joffe, D. Hughes, N. 2006 Hydrogen Fuel Cells for Stationary Power Technology Characterisation and Market Assessment, UKSHEC Social Science Working Paper No. 24, Policy Studies Institute, London. 

Some future goals for both CLRTAP and EU policy include the adoption of transboundary air pollution regulations that address particulate matter and a continued effort in scientific research (i.e. active measures such as technological improvements for stationary and mobile pollution sources and preventative measure such as improving knowledge of biological recovery of eutrophied and acidified waterways). In addition, the impacts of particulate matter on climate change and vice-versa need to be better understood. 

The Environmental Agency of Japan has conducted questionnaire surveys on the emission of air pollutants from stationary sources every three years, in order to obtain information for promotion of air pollution control policy. Based on the results of these surveys, together with the data on emission factors for mobile and other sources, the emission trends for SO2 and NO are shown in Table 5. 

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