并行面向对象数据库中的数据放置

针对并行面向对象数据库的特点,结合异步并行查询执行策略,提出了一种基于对象类的混合式数据放置策略,它包括两个部分:混合式数据划分策略和基于对象类的数据分配策略     

On‐line algorithms for minimizing makespan on batch processing machines

We consider problem of scheduling jobs on‐line on batch processing machines with dynamic job arrivals to minimize makespan. A batch machine can handle up to B jobs simultaneously. The jobs that are processed together from a batch, and all jobs in a batch start and complete at the same time. The processing time of a batch is given by the longest processing time of any job in the batch. Each job becomes available at its arrival time, which is unknown in advance, and its processing time becomes known upon its arrival. In the first part of this paper, we address the single batch processing machine scheduling problem. First we deal with two variants: the unbounded model where B is sufficiently large and the bounded model where jobs have two distinct arrival times. For both variants, we provide on‐line algorithms with worst‐case ratio (the inverse of the Golden ratio) and prove that these results are the best possible. Furthermore, we generalize our algorithms to the general case and show a worst‐case ratio of 2. We then consider the unbounded case for parallel batch processing machine scheduling. Lower bound are given, and two on‐line algorithms are presented. © 2001 John Wiley & Sons, Inc. Naval Research Logistics 48: 241–258, 2001     

基于多子网语言决策图的空管体系绩效评估

为评估空管体系综合绩效水平,制定了关键绩效领域和指标,提出基于多子网语言决策图的群体评估模型。采用多子网策略分析领域及指标间的影响关系,应用语言尺度辅助群体专家建立了领域及指标间的初始判断矩阵和影响连接矩阵。给出了模型的求解方法,在求得各子网内准则的全局权重后,聚合即可得到体系的综合评估值。案例分析表明,相比于不考虑领域及指标间影响的情况,模型结果能更客观、全面地展示各领域及指标的权重,更显著地揭示空管体系间的差距。     

基于合作博弈的智能集群自主聚集研究

智能集群是指由大量智能体构成、采用自组织策略协作完成任务的群体。以无人车集群系统协同监视再入体着靶过程为任务背景,开展智能集群自组织策略的关键技术研究。设计了无人车集群执行再入体着靶协同监视的集群行为模式,提出了基于合作博弈的智能集群自组织策略,各智能体以实现群体聚集为“合作目标”,以降低自身能量消耗为“竞争目标”,开展博弈,基于微粒群算法规划局部路径,最终使群体系统涌现出聚集行为。仿真实验验证了设计的自主聚集策略的有效性。     

正交频分复用水声通信自适应调制算法

分析预估信道长度对信道估计算法的影响规律,提出利用水声通信均衡恢复信号统计量对信道估计质量评估的方法。通过信道长度自适应修正机制,实现对未知水声信道的高精度估计。针对水声信道造成的正交频分复用子载波特性差异,基于信道估计结果,提出在码元总速率、能量约束条件下,各个正交频分复用子载波速率、功率优化分配的自适应调制算法。与传统的等功率、速率分配算法相比,新算法能够显著提升水声通信系统的误码率性能,通过仿真和实地试验,验证了研究内容的有效性。     

Performance analysis of the cultural and creative industry: a network‐based approach

The cultural and creative industries (CCIs) in Taiwan have gradually contributed to the national economy under the impetus of government policies. We employ a two‐stage data envelopment analysis model with an additive efficiency decomposition approach to measure the profitability and marketability of 22 Taiwanese cultural and creative companies. Furthermore, we employ the network‐based ranking approach to identify benchmark inputs/outputs, and the strengths and weakness of each company. Our empirical results show that the profitability of the cultural and creative companies is better than their marketability. Companies in the industries of publishing, creative life, popular music, and cultural content averagely perform better than those in the other three types of CCIs in terms of profitability. Companies in the creative life industry are on average more efficient than those in the other five types of CCIs in terms of marketability. The profitability/marketability matrix of cultural and creative companies is also presented.     

The role of covariate balance in observational studies

Observational data are prevalent in many fields of research, and it is desirable to use this data to make causal inferences. Because this data is nonrandom, additional assumptions are needed in order to construct unbiased estimators for causal effects. The standard assumption is strong ignorability, though it is often impossible to achieve the level of covariate balance that it requires. As such, researchers often settle for lesser balance levels within their datasets. However, these balance levels are generally insufficient to guarantee an unbiased estimate of the treatment effect without further assumptions. This article presents several extensions to the strong ignorability assumption that address this issue. Under these additional assumptions, specific levels of covariate balance are both necessary and sufficient for the treatment effect estimate to be unbiased. There is a trade‐off, however: as balance decreases, stronger assumptions are required to guarantee estimator unbiasedness. These results unify parametric and nonparametric adjustment methods for causal inference and are actualized by the Balance Optimization Subset Selection framework, which identifies the best level of balance that can be achieved within a dataset. © 2017 Wiley Periodicals, Inc. Naval Research Logistics 64: 323–344, 2017     

基于反射内存网的复合导引头联合仿真试验设计

联合仿真试验同时具备实装试验、数学仿真试验和半实物仿真试验的优点,可构建全面逼真的试验环境,其中实时算法和通信技术是关键技术。基于反射内存网技术,进行了复合导引头联合仿真试验总体方案设计,对试验中的时间同步、数据同步等关键问题进行了研究,解决了联合仿真试验中各仿真系统协同及实时通信问题,对联合仿真试验的开展有一定的应用价值。     

Military expenditure and economic growth in Middle Eastern countries and Turkey: a non-linear panel data approach

The economic growth effects of military expenditure have been the subject of a large literature in defence economics. Theories on the economic impacts of military expenditure greatly differ and include arguments that they either enhance economic growth or crowd out productive investments. Empirical literature on defence expenditure and economic growth nexus generally employs linear specifications to investigate the impact of defence expenditures on economic growth. Although it is now well established that many economic variables may have a non-linear data-generating mechanism, it seems that this reality has long been neglected in empirical work on defence–growth nexus. This paper attempts to fill this gap by employing non-linear panel data models to examine the effects of military expenditures on economic growth for Middle Eastern countries and Turkey, for the time period 1988–2012. Results show that the effect of military expenditure on economic growth is nonlinear such that the state of the economy actually determines the effect of the former on the latter. This is important not only in showing asymmetric relationship between these variables but also in revealing the reasons of mixed results of earlier literature.     

Business and peace in the Niger Delta: what we know and what we need to know

The global restructuring of state–society relationships driven by neoliberal logic has not only allowed for the taming of the ‘state’, which has paradoxically accentuated its inadequacies, but has also facilitated, for better or for worse, the emergence of business – especially transnational corporations – as a major political force in global governance. Consequently, while the issues of peace and conflict have traditionally been the concern of governments, businesses are now increasingly being expected to make peace and conflict their concern. However, despite claims and counterclaims that businesses can be moneymakers and peacemakers, analyses of the relationship between business and peace remain largely embryonic. This paper seeks to contribute to this emerging business and peace debate by drawing on insights from the Niger Delta conflict to ascertain what we know and what we need to know if businesses are to become peacemakers in conflict zones in Africa.