Estimating value in a uniform auction

Consider an auction in which increasing bids are made in sequence on an object whose value θ is known to each bidder. Suppose n bids are received, and the distribution of each bid is conditionally uniform. More specifically, suppose the first bid X₁ is uniformly distributed on [0, θ], and the i^th bid is uniformly distributed on [X_i?1, θ] for i = 2, …?, n. A scenario in which this auction model is appropriate is described. We assume that the value θ is un known to the statistician and must be esimated from the sample X₁, X₂, …?, X_n. The best linear unbiased estimate of θ is derived. The invariance of the estimation problem under scale transformations in noted, and the best invariant estimation problem under scale transformations is noted, and the best invariant estimate of θ under loss L(θ, a) = [(a/θ) ? 1]² is derived. It is shown that this best invariant estimate has uniformly smaller mean-squared error than the best linear unbiased estimate, and the ratio of the mean-squared errors is estimated from simulation experiments. A Bayesian formulation of the estimation problem is also considered, and a class of Bayes estimates is explicitly derived.     

Violence and the state: Lessons from Colombia

Whether or not Colombia has improved is a controversial topic. If improvement has occurred, what, if any, lessons from the Colombian model can be learned? The first lesson is that Colombia's problems were caused more by a weak state than by drugs. The second lesson is that improving state capacity requires more than just increased security. The state must also provide the basic social services that citizens require to gain and maintain their support. Additionally, government institutions need to improve their professionalism, protect human rights, and root out impunity and corruption. The alternative is to suffer from new cycles of violence as old foes are vanquished, but new ones emerge.     

Technical note: Worst‐case performance of power‐of‐two policies for serial inventory systems with incremental quantity discounts

This study presents power‐of‐two policies for a serial inventory system with constant demand rate and incremental quantity discounts at the most upstream stage. It is shown that an optimal solution is nested and follows a zero‐inventory ordering policy. To prove the effectiveness of power‐of‐two policies, a lower bound on the optimal cost is obtained. A policy that has a cost within 6% of the lower bound is developed for a fixed base planning period. For a variable base planning period, a 98% effective policy is provided. An extension is included for a system with price dependent holding costs. © 2007 Wiley Periodicals, Inc. Naval Research Logistics, 2007     

Military expenditure,economic growth and structural instability: a case study of South Africa

This paper contributes to the growing literature on the milex-growth nexus, by providing a case study of South Africa and considering the possibility of structural breaks by applying newly developed econometric methods. Using full sample bootstrap Granger non-causality tests, no Granger causal link is found between military expenditure and GDP for 1951–2010, but parameter instability tests show the estimated VARs to be unstable. Using a bootstrap rolling window estimation procedure, however, finds evidence of bidirectional Granger causality in various subsamples. This implies standard Granger non-causality tests, which neither account for structural breaks nor time variation may be invalid.     

Efficiency of equilibria in restricted uniform machine scheduling with total weighted completion time as social cost

In the last decade, there has been much progress in understanding scheduling problems in which selfish jobs aim to minimize their individual completion time. Most of this work has focused on makespan minimization as social objective. In contrast, we consider as social cost the total weighted completion time, that is, the sum of the agent costs, a standard definition of welfare in economics. In our setting, jobs are processed on restricted uniform parallel machines, where each machine has a speed and is only capable of processing a subset of jobs; a job's cost is its weighted completion time; and each machine sequences its jobs in weighted shortest processing time (WSPT) order. Whereas for the makespan social cost the price of anarchy is not bounded by a constant in most environments, we show that for our minsum social objective the price of anarchy is bounded above by a small constant, independent of the instance. Specifically, we show that the price of anarchy is exactly 2 for the class of unit jobs, unit speed instances where the finite processing time values define the edge set of a forest with the machines as nodes. For the general case of mixed job strategies and restricted uniform machines, we prove that the price of anarchy equals 4. From a classical machine scheduling perspective, our results establish the same constant performance guarantees for WSPT list scheduling. © 2012 Wiley Periodicals, Inc. Naval Research Logistics, 2012     

Defence spending and economic growth in South Africa: A supply and demand model*

This paper provides a contribution to the growing corpus of knowledge and understanding of the interaction between economic growth and defence spending in South Africa by specifying a Keynesian simultaneous equation model and estimating the system for the period 1961 to 1997. The model contains a growth equation, a savings equation, a trade balance equation and a military burden equation and when estimated by single equation and systems estimation methods is relatively well specified. There is evidence of an overall negative effect of military spending on the economy over this period, though the significance of individual coefficients is low. There is certainly no evidence of any positive impact, suggesting that cuts in military spending do present an opportunity for improved macroeconomic performance.     

Country survey XII: South Africa

This article examines the relationship between defence expenditure and economic performance in South Africa, both prior to and after that country's first fully democratic election in 1994. Prior to 1994 defence expenditure decisions were largely dominated by non‐economic factors; since then defence spending has declined in reaction to, inter alia, the need to address a number of socio‐economic inequities.

After 1975 in particular, military industrialisation in South Africa placed a disproportionately high burden on the country's industrial resources and natural economic and technical capabilities. However, although this suggests that the opportunity cost of domestic arms production has been fairly high, the country's poor economic and development performance since the mid‐1970s is a function of underlying structural deficiencies and institutional constraints rather than the consequence of inordinately high defence spending levels.     

Cinematic representations of the Mexican Narco War

This essay provides an overview of the eras of Mexican cinema followed by an analysis of 10 Spanish-language narco cinematic representations, an overview of the eras of American cinema followed by an analysis of 10 English language narco cinematic representations, and a conclusion that compares and contrasts the Mexican and US narco war cinematic experience. Due to divergent national trajectories – Mexico is engulfed in narco violence and corruption while the United States is not – more differences than similarities exist between these national cinematic genres. Dark spirituality themes are also increasingly evident in more recent narco war films.     

Factors influencing the modernization of military-investment economic appraisal systems

Budgetary restrictions resulting from the present international economic crisis have tightened the need to improve efficiency in defense spending, leading to the armed forces having to undertake their duties with fewer resources. Previous reports on the subject have looked into the determining factors and effects of military spending but very few studies have analyzed the determinants for the modernization of the methodology for assessing efficiency. Thus, using a multiple regression statistical model, we have analyzed the appraisal systems in place in 28 countries to identify factors that influence the development of economic assessment of military expenditure. Our findings have revealed three factors that may favor the improvement of appraisal systems with regard to military expenditure: the quality of governance, size of the armed forces, and unemployment levels.