All-pay war

We study a model of war in which the outcome is uncertain not because of luck on the battlefield (as in standard models), but because the involved countries lack information about their opponent. In our model their production and military technologies are common knowledge, but their resources are private information. Each country decides how to allocate its resources to production and warfare. The country with the stronger military wins and receives aggregate production. In equilibrium the country with a comparative advantage in warfare allocates all resources to warfare for low resource levels and follows a non-decreasing concave strategy thereafter. The opponent allocates a constant fraction of its resources to warfare for low resource levels and follows an increasing non-linear strategy thereafter. From an ex ante perspective the country with a comparative advantage in warfare is likely to win the war unless its military technology is much weaker than the opponent’s.Conflict; war; all-pay auction; private information

A power law distribution in patients' lengths of stay in hospital

The distribution of patients' lengths of stay in English hospitals is measured by using routinely collected data from 11 years. It is found to be well approximated by a power law distribution spanning over more than 3 decades. To explain this observation, a theoretical resource allocation model is presented. It is based on iterative long-term scheduling of hospital beds, and its main assumption is that future beds are allocated preferentially. This represents a situation where di®erent parts of the health care system compete for resources, with bargaining powers proportional to current resource levels

Tree Trunk Arthropod Faunas as Food Resources for Birds

Author Institution: Department of Zoology, Miami UniversityThe composition, abundance, and relationship to trunk-surface characteristics of the tree-trunk surface arthropod fauna were studied from August, 1984 to January, 1985 in a beech-maple forest in southwestern Ohio. Samples of trunk-surface arthropods were taken monthly from American beech and sugar maple trees. Although resource levels on the two tree species did not differ significantly, arthropod resource levels were dynamic, changing monthly in magnitude and composition. Live arthropods became progressively less abundant as winter approached; non-living/dormant items did not. Results suggest that trunk surface characteristics offer foraging birds few reliable clues about arthropod resource levels

Computing Bounds on Resource Levels for Flexible Plans

A new algorithm efficiently computes the tightest exact bound on the levels of resources induced by a flexible activity plan (see figure). Tightness of bounds is extremely important for computations involved in planning because tight bounds can save potentially exponential amounts of search (through early backtracking and detection of solutions), relative to looser bounds. The bound computed by the new algorithm, denoted the resource-level envelope, constitutes the measure of maximum and minimum consumption of resources at any time for all fixed-time schedules in the flexible plan. At each time, the envelope guarantees that there are two fixed-time instantiations one that produces the minimum level and one that produces the maximum level. Therefore, the resource-level envelope is the tightest possible resource-level bound for a flexible plan because any tighter bound would exclude the contribution of at least one fixed-time schedule. If the resource- level envelope can be computed efficiently, one could substitute looser bounds that are currently used in the inner cores of constraint-posting scheduling algorithms, with the potential for great improvements in performance. What is needed to reduce the cost of computation is an algorithm, the measure of complexity of which is no greater than a low-degree polynomial in N (where N is the number of activities). The new algorithm satisfies this need. In this algorithm, the computation of resource-level envelopes is based on a novel combination of (1) the theory of shortest paths in the temporal-constraint network for the flexible plan and (2) the theory of maximum flows for a flow network derived from the temporal and resource constraints. The measure of asymptotic complexity of the algorithm is O(N O(maxflow(N)), where O(x) denotes an amount of computing time or a number of arithmetic operations proportional to a number of the order of x and O(maxflow(N)) is the measure of complexity (and thus of cost) of a maximumflow algorithm applied to an auxiliary flow network of 2N nodes. The algorithm is believed to be efficient in practice; experimental analysis shows the practical cost of maxflow to be as low as O(N1.5). The algorithm could be enhanced following at least two approaches. In the first approach, incremental subalgorithms for the computation of the envelope could be developed. By use of temporal scanning of the events in the temporal network, it may be possible to significantly reduce the size of the networks on which it is necessary to run the maximum-flow subalgorithm, thereby significantly reducing the time required for envelope calculation. In the second approach, the practical effectiveness of resource envelopes in the inner loops of search algorithms could be tested for multi-capacity resource scheduling. This testing would include inner-loop backtracking and termination tests and variable and value-ordering heuristics that exploit the properties of resource envelopes more directly

The effect of school resources on pupil attainment: a multilevel simultaneous equation modelling approach

Improving educational achievement in UK schools is a priority, and of particular concern is the low achievement of specific groups, such as those from lower socio-economic backgrounds. An obvious question is whether we should be improving the outcomes of these students by spending more on their education. The literature on the effect of educational spending on pupil achievement has a number of methodological difficulties, in particular the endogeneity of school resource levels, and the intra-school correlations in student responses. In this paper, we adopt a multilevel simultaneous equation modelling approach to assess the impact of school resources on student attainment at age 14. This paper is the first to apply a simultaneous equation model to estimate the impact of school resources on pupil achievement, using the newly available National Pupil Database (NPDB)

An Approach to Ad hoc Cloud Computing

We consider how underused computing resources within an enterprise may be harnessed to improve utilization and create an elastic computing infrastructure. Most current cloud provision involves a data center model, in which clusters of machines are dedicated to running cloud infrastructure software. We propose an additional model, the ad hoc cloud, in which infrastructure software is distributed over resources harvested from machines already in existence within an enterprise. In contrast to the data center cloud model, resource levels are not established a priori, nor are resources dedicated exclusively to the cloud while in use. A participating machine is not dedicated to the cloud, but has some other primary purpose such as running interactive processes for a particular user. We outline the major implementation challenges and one approach to tackling them

An Experimental Investigation of Colonel Blotto Games

This article examines behavior in the two-player, constant-sum Colonel Blotto game with asymmetric resources in which players maximize the expected number of battlefields won. The experimental results support all major theoretical predictions. In the auction treatment, where winning a battlefield is deterministic, disadvantaged players use a “guerilla warfare” strategy which stochastically allocates zero resources to a subset of battlefields. Advantaged players employ a “stochastic complete coverage” strategy, allocating random, but positive, resource levels across the battlefields. In the lottery treatment, where winning a battlefield is probabilistic, both players divide their resources equally across all battlefields.Colonel Blotto, conflict resolution, contest theory, multi-dimensional resource allocation, rent-seeking, experiments

Native Plant Diversity Resists Invasion at both Low and High Resource Levels

Human modification of the environment is causing both loss of species and changes in resource availability. While studies have examined how species loss at the local level can influence invasion resistance, interactions between species loss and other components of environmental change remain poorly studied. In particular, the manner in which native diversity interacts with resource availability to influence invasion resistance is not well understood. We created experimental plant assemblages that varied in native species (1–16 species) and/or functional richness (defined by rooting morphology and phenology; one to five functional groups). We crossed these diversity treatments with resource (water) addition to determine their interactive effects on invasion resistance to spotted knapweed (Centaurea maculosa), a potent exotic invader in the intermountain West of the United States. We also determined how native diversity and resource addition influenced plant-available soil nitrogen, soil moisture, and light. Assemblages with lower species and functional diversity were more heavily invaded than assemblages with greater species and functional diversity. In uninvaded assemblages, experimental addition of water increased soil moisture and plant-available nitrogen and decreased light availability. The availability of these resources generally declined with increasing native plant diversity. Although water addition increased susceptibility to invasion, it did not fundamentally change the negative relationship between diversity and invasibility. Thus, native diversity provided strong invasion resistance even under high resource availability. These results suggest that the effects of local diversity can remain robust despite enhanced resource levels that are predicted under scenarios of global change

The Effects of Political and Fiscal Incentives on Local Government Behavior – An Analysis of Fiscal Slack in China

This study examines the determinants of fiscal slack from the perspective of Chinese local government officials. Given China's rapid economic growth over the past 30-plus years, Chinese local governments reportedly hold huge slack resources that attract public scrutiny. In an effort to improve their fiscal performance, some localities recently established budget stabilization funds, following a top-down initiative. However, it remains unclear to what extent fiscal slack has accumulated and which factors affect slack resource levels of Chinese local governments. By employing a panel dataset (249 prefecture-level cities, 1999–2009), this study finds that political and fiscal factors exert significant influence over local officials’ decisions about slack resource levels. The findings of the study bear implications for establishing fiscal rules and improving the performance of sub-national governments in China and other countries

Single mothers in various living arrangements: Differences in economic and time resources

The economic status of single mothers with dependent children has recently been shown to vary greatly according to their living arrangements, a finding with implications for poverty policy and welfare reform. The economic and time resources of single mothers in various living arrangements were compared using the 1987 National Survey of Families and Households. I find that cohabitation is significantly related to increased income adequacy and lesser receipt of public assistance for white mothers, but not for black mothers. Living in the parents' home is significantly related to a reduced likelihood of receipt of public assistance for both white and black single mothers, but living with parents is related to lesser time demands in household work only for white single mothers. Differences in resource levels may be related to the finding that, among those living in the parental household, a large majority of white mothers live with two parents, while a majority of black mothers live with one parent.