On estimating survival for reliability models based on age-related stochastic comparisons

A new class of nonparametric reliability models is introduced and studied. A distribution is said to be better at age s than at age t (sBt) if the residual lifetime at age s is stochastically greater than or equal to the residual lifetime at age t. Applications to various forms of replacement policies, including the cannibalization of failed systems, are noted. For fixed s < t, the problem of estimating a survival curve assumed to belong to the sBt class is addressed using recursive methods. An sBt estimator is derived in closed form, and its uniform strong consistency at an optimal rate of convergence is demonstrated. A simulation study strongly supports the claim that the sBt estimator tends to outperform the empirical survivor function in small- and moderate-size samples. © 1993 John Wiley & Sons, Inc.     

Algorithms for the design of finite-capacity service units

Finite-capacity queues arise naturally in many practical situations, notably in communications and manufacturing engineering. In this article, the matrix formalism of probability distributions of phase type is used to develop fast algorithms to compute various steady-state distributions for the finite-capacity PH/PH/1 queue. This algorithm is an important ingredient in solving nontraditional but significant design problems. Some of these are described as illustrative examples.     

Location-allocation for distribution to a uniform demand with transshipments

This article analyzes the location-allocation problem for distribution from a single fixed origin via transshipment terminals to a continuous uniformly distributed demand. Distribution through terminals concentrates flows on the origin-to-terminal links and transportation economies of scale encourage the use of larger vehicles. Analytical expressions are derived for the optimal terminal locations, the optimal allocation of destinations to terminals, and the optimal transportation cost. Continuous analytic models assume either an allocation, by partitioning the service region into sectors, or terminal locations. This is unlikely to produce an optimal distribution system. The optimal cost is compared to the cost for suboptimal location-allocation combinations. Results indicate that the location decision is not too important if destinations are allocated optimally and that allocation to the nearest terminal may be poor, even with optimal locations. © 1992 John Wiley & Sons, Inc.     

Coercive diplomacy and the Donbas: Explaining Russian strategy in Eastern Ukraine

What were Russia’s objectives in Eastern Ukraine, and why was it seemingly unable to achieve a successful or decisive outcome? In contrast to Russia’s seizure of Crimea, the uprising in Eastern Ukraine was marked by disorganization and chaos. Using proxy and surrogate actors, along with military exercises and the injection of Russian troops, Russia sought to institutionalize a political entity inside Ukraine to influence its domestic politics. In this article, I analyze the mechanisms by which Russia attempted to implement, and later salvage, its strategy. The article contributes to clearer theoretical and practical understanding of limited force in coercive diplomacy, signaling, and a more rigorous treatment of the role and uses of proxy actors.     

Multilateral defense cooperation in the Indo-Asia-Pacific region: Tentative steps toward a regional NATO?

Some U.S. military leaders have asserted that the United States, Japan, Australia, and India and the Republic of Korea are developing multilateral defense cooperation to deter aggression and uphold norms much like North Atlantic Treaty Organization (NATO) has in Europe. Frequent military exercises and China’s threats to freedom of navigation (FoN) and North Korea’s nuclear missiles comprise the motive force for such cooperation. However, cooperation thus far has been trilateral and minimal, given divergent national interests and dispersed geopolitical locations. Cooperation among Japan, Republic of Korea (ROK), and the United States is increasing given the threat, but ROK’s public opinion is divided about Japan. Australia, Japan, and India have increased cooperation with the United States but are reluctant to conduct FoN operations with the United States to challenge China’s expansionism in the South China Sea. If China becomes more aggressive and blocks FoN or seizes territory, development toward an Asian NATO is possible.     

Rising bipolarity in the South China Sea: the American rebalance to Asia and China's expansion

This article synthesizes three elements of power and balancing in the South China Sea (SCS): analytical perspectives on China's behaviour and intentions, the American rebalance to Asia and the dispositions of American allies and partners. Based on extensive interviews and theoretical analysis, it concludes that ‘soft balancing’ backed by American military power provides the optimum chance for resolving the growing dispute. Short to medium-term weakness of Malaysia, Philippines and Vietnam, as well as Japan, means the United States must provide much of the military power while working to build their forces. The most promising alternative is multilateral diplomacy through the Association of Southeast Asian Nations’ Regional Forum, a vehicle for negotiating a Code of Conduct and implementation of the UN Convention on the Law of the Sea. If China remains motivated mainly by defense of realist interests, the costs imposed against expansion will eventually cause recalculation of Beijing's strategy, and soft balancing by the United States and its partners has a chance of working. The constructivist perspective, stressing self-conceptualization of Chinese strategic culture, supports Chinese confidence that patience will eventually bring dominance. If China tries offensively to change the status quo, soft balancing is less likely to influence Beijing. President Xi Jin Ping appears to be offensively asserting power, seeking regional dominance before he is due to step down in 2023. This supports the finding of enhanced risks of unintended escalation in the SCS and the East China Sea.     

Bounding methods for facilities location algorithms

Single- and multi-facility location problems are often solved with iterative computational procedures. Although these procedures have proven to converage, in practice it is desirable to be able to compute a lower bound on the objective function at each iteration. This enables the user to stop the iterative process when the objective function is within a prespecified tolerance of the optimum value. In this article we generalize a new bounding method to include multi-facility problems with l_p distances. A proof is given that for Euclidean distance problems the new bounding procedure is superior to two other known methods. Numerical results are given for the three methods.     

Test for the extreme value and weibull distributions based on normalized spacings

Discussed in this article are tests for the extreme-value distribution, or, equivalently, for the two-parameter Weibull distribution when parameters are unknown and the sample may be censored. The three tests investigated are based on the median, the mean, and the Anderson-Darling A² statistic calculated from a set zⁱ of values derived from the spacings of the sample. The median and the mean have previously been discussed by Mann, Scheuer, and Fertig [10] and by Tiku and Singh [14]. Asymptotic distributions and points are given for the test statistics, based on recently developed theory, and power studies are conducted to compare them with each other and with two other statistics suitable for the test. Of the normalized spacings tests, A² is recommended overall; the mean also gives good power in many situations, but can be nonconsistent.     

求取鱼雷转角射击转角的实用算法

较为详细地推导了鱼雷转角射击公式,根据分鱼雷转向的不同总结出两类求解公式（各种态好都能用两类公式之一来解算）．最后还讨论了所导出的非线性方程的数值解算方法,该算法具有工程应用价值。