In this article, the beginnings of a new approach to the theory of aggregation are developed. The basic idea is that aggregation should involve two things: (a) data over which social preferences are defined should be mapped into a smaller-dimensional space, and (b) there should exist an ordering on that lower-dimensional space such that an improvement in this criterion implies an improvement for any of a class of social preference functions and of a class of individual preference relations defined over the original space. Results are developed which show that this conception of aggregation can yield meaningful results; particularly with respect to comparisons of ‘real national income’ in two situations, for a given economy.

This paper presents very general conditions guaranteeing that a quasi-competitive equilibrium is a Walrasian equilibrium. We also develop a generalization (and a simplified proof) of Nikaido’s and McKenzie’s extensions of the classic Debreu-Scarf theorem on core convergence, and apply the first result to obtain an equivalence between the set of Edgeworth equilibria and the set of Walrasian equilibria in a production economy.

In many instances, when people search a database, they art searching for a best record instead of a record with a particular set of characteristics. Using boolean queries to develop a search strategy to find a best record has proven too difficult, especially for novice users. We construct an optimal decision strategy for finding rite best available alternative that takes into account both the expected value of continued search and the cost of search. rile optimal strategy is intuitively appealing, and can be used as the basis for. heuristics in more complex environments. (C) Elsevier, Paris.

This paper investigates strategies for the acquisition of consumer preference information by a market researcher. Such preference information is obtained by the market researcher through an experimental process that entails polling consumers about their preference profiles with a view to completely specifying the preference order. In this paper, we limit the focus to one or two consumers.

This paper investigates a problem of resource allocation, where a manager allocates discrete resources among multiple agents in a team in a socially optimal manner. In making this allocation, the manager needs to understand the preference orders of the agents for the discrete resources. The manager does this by adopting an information acquisition policy. Three different information acquisition policies are investigated here. The trade off between the amount of information elicited and the costs involved are studied for each of the policies.

This paper investigates a problem of task allocation in Distributed Artificial Intelligence (DAI) systems, where a coordinator allocates tasks among multiple agents in an optimal manner. In making the task allocation, the coordinator needs to understand the preference orders of the agents for the different task bundles. The coordinator does this by adopting an information acquisition strategy that leads to an optimal system welfare. Three different information acquisition strategies are investigated here. The strategies are compared in a noisy environment for the quality of information they provide in terms of the deviation from optimal system welfare. Copyright 1996 Elsevier Science Ltd

deal with an ‘organization’ havingm individual agents (the ‘agents’) and one central agent or agency (the ‘coordinator’), and the problem of allocating a fixed supply ofn commodities among the agents. The coordinator wishes to distribute the commodities in such a way as to maximize an objective function whose arguments are functions known (implicitly) to the individual agents, but not to the coordinator. The more information the coordinator obtains about the individual agents' functions, the better the allocation decision he or she can make; however, gaining such information is costly, so that the coordinator must balance the potential gain against the cost of acquiring additional information. We find a ‘satisficing’ solution to this problem which is computable and which terminates in a finite number of steps.

In the presence of iron, dihydroartemisinin forms free radicals and causes cell death. Since most cancer cells have high rates of iron intake, dihydroartemisinin would have selective cytotoxic effect on cancer cells. The present experiment was designed to study the effect of dihydroartemisinin and ferrous sulfate on the growth of implanted fibrosarcoma in the rat. We found that the growth rate of the tumor was significantly retarded by daily oral administration of ferrous sulfate followed by dihydroartemisinin. No significant tumor growth retardation effect was observed in rats treated with either dihydroartemisinin or ferrous sulfate alone. The drug treatment did not significantly affect body weight compared with untreated tumor-implanted animals and no apparent toxic effect was observed after drug treatment. An artemisinin analog-ferrous salt combination may provide a novel approach for cancer therapy.

Two six-week laboratory experiments were conducted to evaluate effects of pesticides and microcosm size on benthic estuarine macroinvertebrate recolonization. Sediments fortified with the pesticides (fenvalerate: controls, 5 (low) and 50 µg g−1 wet sediment (high); endosulfan: controls, 1 (low) and 10 µg g−1 wet sediment (high)) were fine-grained, organically rich (approximately 3.5% organic carbon and 22% dry weight) material. Relative dominance of the four most abundant taxa in both experiments was consistent among treatments with few exceptions. The amphipod,Corophium acherusicum, dominated abundance in both experiments.

We present a decision model that can be interpreted as an economic decision model for a decision maker under bounded rationality; as a behavioral decision model where the decision maker makes tradeoffs between the accuracy of the decision and the effort to make the decision; as a general model of computation amenable to both von Neuman computers and parallel computers; as a model for constructing information systems from a library of reusable code or objects; and as a model of organizational decision making. Although the model is general enough to encompass these (plus other) areas, it is powerful enough to achieve interesting results when properly specialized.

Explores a multi-agent resource allocation problem in an environment of incomplete information. The paper posits the existence of a central policy maker who integrates information acquisition with decision making, in order to optimally allocate resources among multiple agents. The study focuses on three salient aspects: first, the policy maker uses a nonparametric revealed preference approach for the elicitation of each agent's preference profiles. This allows the policy maker to avoid distorting the allocation decision and emerging with suboptimal allocations. Second, the process of information gathering and decision making is a challenging task in view of the extremely large numbers of possible profiles for each agent, even for problems of modest size. To find an optimal allocation, the policy maker can use schemes that utilize partial preference information to handle the complexity of the problem. Third, the incorporation of costs into the information process and the minimal assumptions made about the problem environment allow the policy maker to realistically analyze the resource allocation problem. >

Flow-through acute and early-life-stage (ELS) toxicity tests were conducted with topsmelt (Atherinops affinis), a Pacific coast saltwater fish, and fenvalerate, a synthetic pyrethroid insecticide. The 96-h LC50 for juvenile fish was 0.66-mu-g/L. In the 30-d ELS test with laboratory-spawned embryos, average measured fenvalerate concentrations were nondetectable (< 0.075-mu-g/L) in two control treatments, 0.14, 0.34, 0.82, 1.5, and 3.2-mu-g/L. Survival of embryos to hatching ranged from 94 to 100%, with no statistically significant differences among treatments. No fry survived exposure to fenvalerate concentrations greater-than-or-equal-to 0.82-mu-g/L; overall survival in lower concentrations and control treatments ranged from 86 to 97%. There were no consistent concentration-dependent differences in weight between fish in the carrier-control treatment and fish exposed to fenvalerate. Mean wet weights of surviving fish ranged from 16.9 mg in 0.34-mu-g/L to 20.3 mg in 0.14-mu-g/L. The average bioconcentration factor for fish exposed to 0.14 and 0.34-mu-g fenvalerate per liter was 315.

The measurement of aggregate welfare is one of the oldest endeavors of economics, dating from the time of Dupuit [17] and Marshall [27] and continuing in contemporary times with the work of Hicks [23]. The implicit assumptions involved in such a pursuit have, however, rarely been formulated. It is the purpose of the present paper to fill this gap.