南方三年游击战争中的谭余保

1934年8月,湘赣苏区的主力红军红6军团奉命西征后,国民党军对苏区大举进攻,根据地越来越小,革命力量遭受重大损失.在这危急时刻,原湘赣省苏维埃政府主席谭余保组建中共湘赣临时省委,任省委书记兼组织部长,同时组建游击司令部,任政治委员兼司令员,运用灵活机动的游击战术,领导了湘赣边三年游击战争,同敌人进行了艰苦卓绝的斗争.     

Optimizing usage and maintenance decisions for k‐out‐of‐n systems of moving assets

We consider an integrated usage and maintenance optimization problem for a k‐out‐of‐n system pertaining to a moving asset. The k‐out‐of‐n systems are commonly utilized in practice to increase availability, where n denotes the total number of parallel and identical units and k the number of units required to be active for a functional system. Moving assets such as aircraft, ships, and submarines are subject to different operating modes. Operating modes can dictate not only the number of system units that are needed to be active, but also where the moving asset physically is, and under which environmental conditions it operates. We use the intrinsic age concept to model the degradation process. The intrinsic age is analogous to an intrinsic clock which ticks on a different pace in different operating modes. In our problem setting, the number of active units, degradation rates of active and standby units, maintenance costs, and type of economic dependencies are functions of operating modes. In each operating mode, the decision maker should decide on the set of units to activate (usage decision) and the set of units to maintain (maintenance decision). Since the degradation rate differs for active and standby units, the units to be maintained depend on the units that have been activated, and vice versa. In order to minimize maintenance costs, usage and maintenance decisions should be jointly optimized. We formulate this problem as a Markov decision process and provide some structural properties of the optimal policy. Moreover, we assess the performance of usage policies that are commonly implemented for maritime systems. We show that the cost increase resulting from these policies is up to 27% for realistic settings. Our numerical experiments demonstrate the cases in which joint usage and maintenance optimization is more valuable. © 2017 Wiley Periodicals, Inc. Naval Research Logistics 64: 418–434, 2017     

不确定性作战任务形式化描述方法

针对复杂作战环境下作战任务的不可预知性特点,对不确定性任务的形式化描述方法进行了深入研究。分析不确定环境导致的任务分解和执行过程中存在的不确定性因素,从任务本身的不确定性、任务之间关系不确定性以及作战单元执行不确定性等方面,对不确定性任务进行了形式化描述,提出了不确定性任务形式化描述流程,最后通过一个实例对所提方法进行了验证。     

Exact expected values of variance estimators for simulation

We formulate exact expressions for the expected values of selected estimators of the variance parameter (that is, the sum of covariances at all lags) of a steady‐state simulation output process. Given in terms of the autocovariance function of the process, these expressions are derived for variance estimators based on the simulation analysis methods of nonoverlapping batch means, overlapping batch means, and standardized time series. Comparing estimator performance in a first‐order autoregressive process and the M/M/1 queue‐waiting‐time process, we find that certain standardized time series estimators outperform their competitors as the sample size becomes large. © 2007 Wiley Periodicals, Inc. Naval Research Logistics, 2007     

过氧化氢改善柴油机燃烧的试验研究

提出采用过氧化氢组液参与柴油机的燃烧,改善柴油机燃烧过程,同时降低油耗与排放的新方法。分析了过氧化氢对柴油机燃烧过程的影响机理,从实用角度设计并开发了一种过氧化氢组液供给系统,并在135柴油机单缸机上试验研究过氧化氢组液消耗量对比油耗、烟度、排温及NOx的影响。     

Mailed Fists and Velvet Gloves: The Relevance of Smart Power to Singapore’s Evolving Defence and Foreign Policy

Abstract

This paper critically assesses the conceptual utility of smart power to Singapore’s evolving defence and foreign policy and behaviour. First, as a political concept adopted by the United States for its post-Afghanistan strategy, smart power does not travel easily. With qualifications, however, the notion is relevant to Singapore’s policy pragmatism and its emphasis on deterrence and diplomacy. Second, Singapore’s willingness to employ its military assets in disaster relief and peacekeeping arguably hews most closely to smart power’s mix of hard and soft approaches. Third, Singapore’s contributions to global governance, albeit limited, imply a rethinking among its leaders on the place of values in its policy.