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81.
82.
基于宏程序的椭圆轮廓的数控车加工 总被引:1,自引:0,他引:1
宏程序在数控编程中有着广泛的应用。文章结合两种椭圆曲线宏程序编程实例,介绍了宏程序在非圆曲线中的编制方法和技巧,分析表明:宏程序数控编程具有编程快捷和程序短小精悍的显著特点,尤其适用于一些含非圆曲线零件的数控编程加工。 相似文献
83.
Jonathan P. Caulkins Maria Dworak Gustav Feichtinger Gernot Tragler 《Journal of Economics》2000,71(3):227-253
Price-raising drug enforcement suppresses drug use, but it is expensive and may increase property crime. This has led to contradictory
recommendations concerning how drug enforcement should or should not be used. We reconcile these recommendations by incorporating
the enforcement's effects on both drug use and on property crime within an optimal-control model that recognizes whether convicted
drug-involved property offenders are merely incarcerated or whether they receive some form of drug treatment. 相似文献
84.
本文阐述了资本结构的优化目标,结合线性规划与灰色关联投影法构建了一个资本结构优化模型。 相似文献
85.
客户订单允诺管理是在市场全球化的背景下.综合考虑各种资源有限性,对客户的订单给予准确的答复.因而具有很好的应用前号。文章对现有客户订单允诺模型做出改进,在供应链资源即物料和产能双重限制下,加入客户优先级约束,通过建立模型求解,给出合理的客户订单允诺机制。文中不仅定性分析客户优先级.而且将客户优先级量化为客户价值来表示,使该订单允诺管理机制更为有效.更有利于企业的长期可持续发展。 相似文献
86.
Energy policy, environmental planning and economic development play a key role in sustainable development. Sustainable development requires suitable and strategic policies satisfying multiple and conflicting objectives. Fuzzy goal programming (FGP) is a well-known approach in multi-criteria decision-making for its practical application. In this article, a FGP approach is proposed to analyse environmental, energy and sustainability goals of India by the year 2030 with reference to the key economic sectors of India. The presented model analyses the improvement opportunities, requirement of efforts and implementation of the sustainable development plans. Numerical illustration is also provided for validation and application of the proposed model. 相似文献
87.
Assessment of the effect of the financial crisis on agents’ expectations through symbolic regression
Agents’ perceptions on the state of the economy can be affected during economic crises. Tendency surveys are the main source of agents’ expectations. The main objective of this study is to assess the impact of the 2008 financial crisis on agents’ expectations. With this aim, we evaluate the capacity of survey-based expectations to anticipate economic growth in the United States, Japan, Germany and the United Kingdom. We propose a symbolic regression (SR) via genetic programming approach to derive mathematical functional forms that link survey-based expectations to GDP growth. By combining the main SR-generated indicators, we generate estimates of the evolution of GDP. Finally, we analyse the effect of the crisis on the formation of expectations, and we find an improvement in the capacity of agents’ expectations to anticipate economic growth after the crisis in all countries except Germany. 相似文献
88.
Charitable foundations and government programmes should endeavour to allocate their limited resources to best serve their constituents. Yet, mathematical programming techniques are rarely used despite overwhelming evidence of their superiority in selecting projects that yield higher levels of total benefits. We present a novel ‘hybrid selection model’ that combines binary linear programming and heuristic rank-based models applied to two case studies. The first case focuses on providing services to women and shows a hybrid model would have selected the top three ‘signature’ projects and maintained an above-average overall project benefit while securing a 180% improvement in the number of projects funded, a 66% improvement in the number of women served and a 132% improvement in the total benefit achieved. In the second case, we apply the hybrid approach to data from the US government’s largest forest preservation programme and demonstrate that the hybrid approach could allow the programme to select up to 11 top-scoring projects while still achieving a 97% gain in the total overall benefit compared to their traditional method. These case studies show that the hybrid approach has the potential to be applied in a variety of settings and improve how foundations and programmes achieve their goals. 相似文献
89.
本文简述了可编程控制器(PLC)的基本特点和发展情况,介绍了PLC的顺序功能图、梯形图、功能模块图、指令表和结构文本等编程语言及其功能特点,阐述了PLC在编程过程中梯形图与指令表语言编程的规则和注意事项等。熟练掌握PLC程序的编程语言、编程方法及编程注意事项,对于PLC编程的快速入门及工程应用具有十分重要的意义。 相似文献
90.
This paper presents a strategic growth model with endogenous time preference. Due to the potential lack of concavity and the differentiability of the value functions associated with each agent’s problem, we employ the theory of monotone comparative statics and supermodular games based on order and monotonicity properties on lattices. In particular, we provide the sufficient conditions of supermodularity for dynamic games with open-loop strategies based on two fundamental elements: the ability to order elements in the strategy space of the agents and the strategic complementarity which implies upward sloping best responses. The supermodular game structure of the model lets us provide the existence and the monotonicity results on the greatest and the least equilibria. We sharpen these results by showing the differentiability of the value function and the uniqueness of the best response correspondences almost everywhere and show that the stationary state Nash equilibria tend to be symmetric. Finally, we numerically analyze to what extent the strategic complementarity inherent in agents’ strategies can alter the convergence results that could have emerged under a single agent optimal growth model. In particular, we show that the initially rich can pull the poor out of the poverty trap even when sustaining a higher level of steady state capital stock for itself. 相似文献