数控加工工艺与编程课程教学体系建构

数控加工工艺与编程是应用型本科院校机械设计制造及其自动化专业的重要基础课程。而从企业对数控加工工艺与编程人才的需求能力上看,他们应具有良好的数学基础;一定的产品制造基础知识;具备数控机床的操作、日常维护等6种能力。为此,将数控加工工艺与编程能力分解成对应的支撑课程群,建构理论教学体系和实践教学体系两方面。通过教学改革收到了较好的效果,学生学习效果好,工程能力得到明显加强。     

Forecasting technology diffusion: a new generalisation of the logistic model

The present research proposes a new generalisation of the logistic model aiming at technology diffusion forecasting. Regarding criticisms and failures reported in the literature to apply logistic function for long-term forecasting, in our work we focused on short-term accuracy of forecast. To formulate the model, based on mathematical approximation, at first the differential equation governing the diffusion process is found and then by solving the derived differential equation, the forecast function is obtained. In all steps, mathematical tools from numerical analysis are used. We compared the New Generalized Logistic Model with eight of the most renowned models in the literature. The model led to more accurate fits and forecasts than those obtained from other models we applied for comparison.     

On the performance of the Chow-Lin procedure for quarterly interpolation of annual data: Some Monte-Carlo analysis

Most of the countries of the OECD offer quarterly estimates of their national growth or of their Gross National Product. Official Statistical Agencies in western countries have to deal with the problem of estimating Quarterly National Accounts series congruently with Annual National Accounts. In Spain, the Instituto Nacional de Estadística uses the Chow-Lin disaggregation method, which is based on information provided by a group of high-frequency related variables, to estimate the quarterly components of National Accounts from annual components. In this paper, we analyse the relative quality of the estimates obtained through the Chow-Lin procedure, under different sets of hypotheses.JEL Classification: C15, C43, M40We are grateful to Maria Amparo Ripoll for her assistance. The authors also wish to thank three anonymous referees and an editor for their constructive suggestions and comments. This research was partially made during the stay of the first author at the Universidad Carlos III de Madrid. It has been partially supported by the research project DGCYT PB98-1460.     

Where can obesity management policy make the largest impact? Evaluating sub-populations through a microsimulation approach

Background: There is a critical need to focus limited resources on sub-groups of patients with obesity where we expect the largest return on investment. This paper identifies patient sub-groups where an investment may result in larger positive economic and health outcomes.

Methods: The baseline population with obesity was derived from a public survey database and divided into sub-populations defined by demographics and disease status. In 2016, a validated model was used to simulate the incidence of diabetes, absenteeism, and direct medical cost in five care settings. Research findings were derived from the difference in population outcomes with and without weight loss over 15 years. Modeled weight loss scenarios included initial 5% or 12% reduction in body mass index followed by a gradual weight regain. Additional simulations were conducted to show alternative outcomes from different time courses and maintenance scenarios.

Results: Univariate analyses showed that age 45–64, pre-diabetes, female, or obesity class III are independently predictive of larger savings. After considering the correlation between these factors, multivariate analyses projected young females with obesity class I as the optimal sub-group to control obesity-related medical expenditures. In contrast, the population aged 20–35 with obesity class III will yield the best health outcomes. Also, the sub-group aged 45–54 with obesity class I will produce the biggest productivity improvement. Each additional year of weight loss maintained showed increased financial benefits.

Conclusions: This paper studied the heterogeneity between many sub-populations affected by obesity and recommended different priorities for decision-makers in economic, productivity, and health realms.     

资产证券化信用评级:国外模型方法及其借鉴

资产证券化作为金融重大创新之一,信用评级模型化分析的重点是预期损失的预测.本文通过对国外信用评级机构进行资产证券化信用评级所采用的模型方法的综合评述与研究,提出了对中国资产证券化信用评级的借鉴意义.     

县(市)级土地利用总体规划中耕地需求量预测方法及其应用

科学准确地预测耕地需求量,是制定县(市)级土地利用总体规划的基础.文章根据中国南方某县1996-2005年来的耕地变更调查统计数据,分别采用趋势分析法、回归分析法、指数平滑法、GM(1,1)模型法和灰色-马尔柯夫链模型的方法,对该地区耕地总量进行了模拟和预测.不同方法的预测结果表明,基于灰色-马尔柯夫链方法的预测结果更加准确可靠,更有利于土地管理决策者的经济决策行为.在当前耕地利用方式的背景下,灰色-马尔柯夫链模型可以作为县(市)级土地利用总体规划中耕地需求量预测方法的一种好选择.     

Towards multi-system sociotechnical transitions: why simulate

A number of research frameworks have been developed for studying sociotechnical transitions. These are complex phenomena, particularly those involving multi-system interactions. Given these characteristics, the paper discusses the challenges in studying transitions solely through inductive inference methods. It argues that transition research has reached a point where taking the next step should include modelling and simulation as part of the standard methodological exploratory toolkit for studying the intensity, nature and timing of system interaction that lead to transitions and for producing timely and robust policy recommendations.     

国际贸易对碳减排协议的促进作用——理论框架及减排意愿的数值一般均衡情景模拟

全球碳减排谈判是具有外部性特征的多方合作博弈。文章首先构建一个单一商品无贸易多国模型,对各国的碳减排意愿进行刻画,利用相关数据对不同情景下的各国碳减排意愿进行数值一般均衡模拟;在此基础上,将国际贸易因素引入模型,重新对各国的减排意愿进行情景模拟。数值模拟结果表明:(1)经济规模越大,全球变暖持续的时间跨度越长,温度上升带来的效用损失越大,各国单方面减排意愿越强;(2)国际贸易的存在更有利于各国碳减排意愿的提高,因为各国通过减产实现减排的同时,其贸易条件得到改善,从而将减产带来的效用损失部分转嫁到其他各国;(3)当前,假借碳减排之名而抬头的新贸易保护主义不仅无法促进各国碳减排,反而将阻碍全球碳减排协议的达成。     

主从系统自跟踪调速方案的设计与仿真

设计了一种采用单片机和变频器组成的主从系统自跟踪调速方案．首先通过高精度光栅拾取主动系统的转速信号,由单片机处理后得到转速大小．当主动系统转速变化时,通过变频控制使从动系统的转速做跟随变化．重点说明了该控制方法的基本原理和设计原理,并通过proteus对系统的硬件电路和软件程序进行仿真,表明该控制方法达到设计要求．     

数控技术应用型人才调研及其岗位群分析

职业院校的数控技术应用专业,已经建设了近二十年,通过深入调研,了解机械制造企业人才状况,细致分析任职岗位群,掌握企业未来数控人才需求,为学院深入开展教学改革提供了可靠依据。