跳频信号的归一化多普勒频差最大似然估计

针对双站定位涉及的跳频信号多普勒频差估计问题,提出了归一化的频差最大似然估计算法,利用两个定位站接收到的跳频脉冲串信号,构建一个关于基准跳频频率多普勒频差的似然函数,通过网格搜索得到使似然函数最大的多普勒频差估计,既解决了跳频信号在不同跳频频率上多普勒频差不一致的问题,又充分利用在不同频率的脉冲串信号提高了多普勒频差估计精度。通过仿真对算法的性能进行了评估,结果表明,与基于子空间的算法比较,在脉冲数达到240个时,所提算法执行效率提升30%以上。     

高校学生信息管理系统中工作流的分析

根据高校的需求和工作流技术的应用现状,文章提出了一个基于工作流技术的高校学生信息管理系统的解决方案。工作流技术在学生管理系统中的应用包括流程的定义、使用、提示和监控。流程的定义使用π演算实现,流程的使用、提示和监控主要由工作流引擎实现。高校学生信息管理系统整合工作流技术,不但保证了高校学生信息管理系统的可靠性,而且提高了该系统的扩展性。     

直列四缸四冲程八气门汽车发动机的气门间隙调整

介绍了发动机之所以要留气门间隙的原因及影响,确定了直列四缸四冲程八气门发动机间隙调整的顺序,与具体调整方法,并对其调整顺序做了一个简单、易记的总结。     

基于聚类算法的电子商务信息集成研究

随着我国电子商务发展的不断深入,这种新型的商业模式提高了对互联网情报信息搜索量和质的要求;元搜索引擎技术的不断进步使信息检索量有了很大的提高,但检索响应时间和检索准确度成为制约该技术在电子商务领域应用的瓶颈;本文通过基于传统的k-means聚类算法,优化了其类别选择机制获得了信息检索的高准确度和快速响应;实证结果表明,优化的k-means聚类算法具有较高的聚类质量和算法弹性,是元搜索引擎技术的有利补充。     

人民银行国库资金风险点的查找与防范

人民银行国库部门的资金风险主要是内控体系不健全,内控制度执行不到位。构建国库部门内控体系的基本原则,建立科学高效的国库业务流程,制定重点环节风险防范机制,针对风险点落实具体风险防范措施,是人民银行国库资金风险点查找与防范的有效方法。     

Relevance of Fundraising Charities’ Content-Marketing Objectives: Perceptions of Donors,Fundraisers, and Their Consultants

Many fundraising charities invest heavily in content marketing, often using consultants to direct their content-marketing efforts. Thus it is vital to establish whether certain key aims of content marketing suggested by literature in the field actually match the aspects of content marketing deemed most important by charity donors. This paper examines the significance attached by samples of charities, donors, and content-marketing consultancies to four possible major objectives of content marketing—the attainment of high–search-engine-results-page rankings, image enhancement through impression management, the stimulation of public perceptions of organizational transparency, and the creation of messages that “go viral.” Several major differences in perceptions emerged among the three groups, with substantial implications for how fundraising charities should manage their content-marketing programs and activities. Charity managements need to consider carefully and critically the possible returns on large-scale expenditures intended to pursue the putative aims of content marketing that are routinely advocated by practitioner and academic literature.     

Integrating nanotechnology into agri-food systems research in India: A conceptual framework

The implications of current trends in nanotechnology for the agri-food sector in India are assessed. Using published literature and patents data, a model to organize the information is developed through a specially designed database. The database allows mapping research themes in nanotechnology to specific sectors in the agricultural value chain to enable a rational assessment of the potential applications of nanotechnology in the agri-food sector, identifying and prioritizing research needs across the agricultural value chain, and assessing the environmental and societal implications of this emerging technology.     

电控发动机加速不良教学过程设计

本文以喷油器引起的电控发动机加速不良故障为例,采用任务驱动和六步教学的方式进行了教学设计,以引起学生的学习兴趣,增强学生的动手能力,进一步提高教学质量。     

Non-permutation flowshop scheduling in a supply chain with sequence-dependent setup times

In this paper, we consider a flowshop scheduling problem with sequence-dependent setup times and a bicriteria objective to minimize the work-in-process inventory for the producer and to maximize the customers' service level. The use of a bicriteria objective is motivated by the fact that successful companies in today's environment not only try to minimize their own cost but also try to fulfill their customers' need. Two main approaches, permutation and non-permutation schedules, are considered in finding the optimal schedule for a flowshop. In permutation schedules the sequence of jobs remains the same on all machines whereas in non-permutation schedule, jobs can have different sequence on different machines. A linear mathematical model for solving the non-permutation flowshop is developed to comply with all of the operational constraints commonly encountered in the industry, including dynamic machine availabilities, dynamic job releases, and the possibility of jobs skipping one or more machines, should their operational requirements deem that it was necessary. As the model is shown to be NP-hard, a metasearch heuristic, employing a newly developed concept known as the Tabu search with embedded progressive perturbation (TSEPP) is developed to solve, in particular, industry-size problems efficiently. The effectiveness and efficiency of the search algorithm are assessed by comparing the search algorithmic solutions with that of the optimal solutions obtained from CPLEX in solvable small problem instances.     

Flexibility at the Margin and Labor Market Volatility in OECD Countries*

We study the business‐cycle behavior of segmented labor markets with flexibility at the margin (e.g., just affecting fixed‐term contracts). We present a matching model with temporary and permanent jobs (i) where there is a gap in the firing costs associated with these types of jobs and (ii) where there are restrictions in the creation and duration of fixed‐term contracts. We show that a labor market with ``flexibility at the margin'' increases the unemployment volatility with respect to one that is fully regulated. This analysis yields new insights into the interpretation of the recent volatility changes witnessed in the OECD area.