基于旅游消费偏好的秦岭北麓观光农业园发展研究

本文选取秦岭北麓观光农业进仃实证研究，通过大量资料收集和野外考察，在分析其存在问题的基础上，从旅游者消费偏好的角度出发，运用spss和数据统计等方法分析了其目标客源市场对观光农业的资源特色偏好、园区类型偏好、住宿偏好、消费意愿等，从而得出秦岭北麓发展观光农业旅游具有良好前景的结论，并最终有针对性地提出一系列发展措施，为秦岭北麓观光农业园的发展提供了强有力的指导方向。     

Markov random-field models for estimating local labour markets

Summary. This work is motivated by data on daily travel-to-work flows observed between pairs of elemental territorial units of an Italian region. The data were collected during the 1991 population census. The aim of the analysis is to partition the region into local labour markets. We present a new method for this which is inspired by the Bayesian texture segmentation approach. We introduce a novel Markov random-field model for the distribution of the variables that label the local labour markets for each territorial unit. Inference is performed by means of Markov chain Monte Carlo methods. The issue of model hyperparameter estimation is also addressed. We compare the results with those obtained by applying a classical method. The methodology can be applied with minor modifications to other data sets.     

一类特殊的有界变量目标规划的算法

对一类从m个决策变量中选择n(n≤m)个决策变量的有界变量目标规划问题,本文用0-1变量建立了它的数学模型,并提出了一种目标规划分层序列的改进算法及一种启发式算法。     

问题解决法在“电路CAD”课程教学中的应用

＂电路CAD＂是一门实践性很强的课程,授课老师应以如何提高学生的学习兴趣与学习效果为教学目标。问题解决法是指在教学过程中以＂围绕实践、重在应用＂为原则,引导学生带着问题去学习的启发式教学方法,该教学方法可以激发学生联系实际中有趣的现象,理解所学知识间的内在联系,探索问题的解决方案。通过问题解决法在＂电路CAD＂教学中的应用,调动了学生的学习积极性,优化了课堂教学,提高了教学效果,是一种适合在＂电路CAD＂教学中使用的方法。     

A reactive tabu search algorithm for the vehicle routing problem with simultaneous pickups and deliveries

The vehicle routing problem with pickups and deliveries (VRPPD) extends the vehicle routing problem (VRP) by allowing customers to both send and receive goods. The main difficulty of the problem is that the load of vehicles is fluctuating rather than decreasing as in the VRP. We design a reactive tabu search metaheuristic that can check feasibility of proposed moves quickly and reacts to repetitions to guide the search. Several new best solutions are found for benchmark problems.     

An investigation into the vehicle routing problem with time windows and link capacity constraints

In this work, we investigate a new, yet practical, variant of the vehicle routing problem called the vehicle routing problem with time windows and link capacity constraints (VRPTWLC). The problem considers new constraints imposed on road links with regard to vehicle passing tonnage, which is motivated by a business project with a Hong Kong transportation company that transports hazardous materials (hazmats) across the city and between Hong Kong and mainland China. In order to solve this computationally challenging problem, we develop a tabu search heuristic with an adaptive penalty mechanism (TSAP) to help manage the company's vehicle fleet. A new data set and its generation scheme are also presented to help validate our solutions. Extensive computational experiments are conducted, showing the effectiveness of the proposed solution approach.     

Point‐of‐Use Hybrid Inventory Policy for Hospitals

Modern point‐of‐use technology at hospitals has enabled new replenishment policies for medical supplies. One of these new policies, which we call the hybrid policy, is currently in use at a large U.S. Midwest hospital. The hybrid policy combines a low‐cost periodic replenishment epoch with a high‐cost continuous replenishment option to avoid costly stockouts. We study this new hybrid policy under deterministic and stochastic demand. We develop a parameter search engine using simulation to optimize the long‐run average cost per unit time and, via a computational study, we provide insights on the benefits (reduction in cost, inventory, and number of replenishments) that hospitals may obtain by using the hybrid policy instead of the commonly used periodic policies. We also use the optimal hybrid policy parameters from the deterministic analysis to propose approximate expressions for the stochastic hybrid policy parameters that can be easily used by hospital management.      

启发式认知下的会计信息价值相关性研究

通过借鉴行为经济学对投资者启发式认知方式研究的发展,本文发现,目前的会计研究基本忽视了会计信息的价值相关性与投资者在短时间内的决策特征有着密切的联系,我国的一些研究成果认为上市公司的信息披露都存在"好消息早、坏消息晚"的现象,并且提出以报表发布时间的早晚采衡量及时性的观点.对此,本文结合我国特殊的制度背景,探讨了在新信息即将发布前的短时间窗口中市场反应的具体诱因,发现投资者的心态和认知过程对会计信息的价值相关性影响较大,而报表发布时间并不构成会计信息价值相关性的影响因素,我国当前制度仍存在着不利于投资者保护的潜在风险.     

Some heuristic algorithms for total tardiness minimization in a flowshop with blocking

The flowshop scheduling problem with blocking in-process is addressed in this paper. In this environment, there are no buffers between successive machines; therefore intermediate queues of jobs waiting in the system for their next operations are not allowed. Heuristic approaches are proposed to minimize the total tardiness criterion. A constructive heuristic that explores specific characteristics of the problem is presented. Moreover, a GRASP-based heuristic is proposed and coupled with a path relinking strategy to search for better outcomes. Computational tests are presented and the comparisons made with an adaptation of the NEH algorithm and with a branch-and-bound algorithm indicate that the new approaches are promising.