Simultaneous inference for treatment regimes

A viable dynamic treatment regime refers to decisions regarding how different treatments and dose levels are tailored through time to match with the patient’s health status. In the therapy for cancer or diseases that require multiple stages of treatments, the effect of preceding treatment (such as growing back of solid tumors or regime-related toxicity) critically influences the selection of treatment in the following stage. So far, analyses of dynamic regimes mainly focus on marginal mean models under the assumption of sequential randomization in a clinical trial. Inference conclusions regarding multiple regimes are normally conservative due to different combinations in the formation of treatment regimes. In this article, we propose a simultaneous confidence interval method to identify treatment regimes that are significantly different from the bulk of the treatment combinations. The new method is applied to analyze the dynamic treatment regimes (DTRs) prostate cancer trial which includes treatment combinations of four chemotherapies at multiple stages. The new method detects a discernible effect of the regime taxane–estramustine–carboplatin (TEC) followed by cyclophosphamide, vincristine, and dexamethasone (CVD), when it is compared with other four regimes starting with CVD.     

An investigation into a new class of vehicle routing problem with backhauls

A new version of the vehicle routing problem with backhauls is presented. In this new problem backhauls are not restricted to be visited once all linehaul customers have been served, neither are backhaul customers fully mixed with linehaul customers. In this problem the user based on his or her experience, the vehicle capacity, the type of products and the type of vehicle used, can define the position along a route from which the first backhaul customer may be visited. An insertion-type heuristic is put forward for this class of problems. An analysis of the improvement in route cost obtained by allowing a relaxation in the restriction of the mix of linehaul and backhaul customers is reported.     

浅谈启发式教学方法在“管理学基础”课程中的运用

教学界一直倡导将启发式教学方法运用于实践操作中去。而在不同科目和层次的课程中,其具体的方法又是多样的。以"管理学基础"为例,探讨启发式教学方法的运用。根据该课程的特点,主要可以采用巧妙设置问题、适当引入相关的经典案例、与实践活动环节相互结合等途径来达到启发式教学的良好效果。     

Designing a tabu search algorithm for the two-stage flow shop problem with secondary criterion

This paper discusses the process of desigining a tabu search-based heuristic for the two-stage flow shop problem with makespan minimization as the primary criterion and the minimization of total flow time as the secondary criterion. A factorial experiment is designed to analyse thoroughly the effects of four different factors, i.e. the initial solution, type of move, size of neighbourhood and the list size, on the performance of the tabu search-based heuristic. Using the techniques of evolution curves, and response tables and response graphs, coupled with the Taguchi method, the best combination of the factors for the tabu search-based heuristic is identified, and the effectiveness of the heuristic algorithm in finding an optimal solution is evaluated by comparing its performance with the best known heuristic to solve this problem.     

历史文化名城旅游开发中的不谐和因子研究

城市的旅游资源丰富,并非就一定能够很好地发展旅游业。我国历史文化名城在旅游开发过程中,受资源、设施、决策、科技等客观和主观因素的影响,产生诸多不谐和因子。这些不谐和因子主要表现在两个方面:一是旅游资源本身,这是客观存在的问题;二是旅游资源在向旅游业转化过程中的问题,这是人为的主观原因造成的。科学制订保护与开发的规划方案,综合治理好旅游整体大环境,适度设计抽象人文吸引物的转化方式,理性突出古特色建设,逐步消除利用中的不谐和因子,是实现资源与旅游业共生发展的良好模式。     

On step fixed-charge transportation problem

The fixed-charge problem is a nonlinear programming problem of practical interest in business and industry. One of its variations is the fixed-charge transportation problem (FCTP) where fixed cost is incurred for every route that is used in the solution, along with the variable cost that is proportional to the amount shipped. That cost structure causes the value of the objective function Z to also behave like a step function. Each time we open or close a route the objective function jumps a step. The step fixed-charge transportation problem (SFCTP) is a variation of the FCTP where the fixed cost is in the form of a step function dependent on the load in a given route. While the value of the objective function Z in the FCTP is a step function, the introduction of the step fixed cost in the SFCTP results in the objective function Z being itself a step function with many more steps. Fixed-charge problems are usually solved using sophisticated analytical or computer software. This paper discusses the theory of SFCTP and presents a computationally simple heuristic algorithm for solving small SFCTPs.     

Revenue Management in Order‐Driven Production Systems

This article investigates the effectiveness of a tactical demand‐capacity management policy to guide operational decisions in order‐driven production systems. The policy is implemented via a heuristic that attempts to maximize revenue by selectively accepting or rejecting customer orders for multiple product classes when demand exceeds capacity constantly over the short term. The performance of the heuristic is evaluated in terms of its ability to generate a higher profit compared to a first‐come‐first‐served (FCFS) policy. The policies are compared over a wide range of conditions characterized by variations in both internal (firm) and external (market) factors. The heuristic, when used with a Whole Lot order‐processing approach, produces higher profit compared to FCFS when profit margins of products are substantially different from each other and demand exceeds capacity by a large amount. In other cases it is better to use the heuristic in conjunction with the Split Lot order‐processing approach.     

游必有方——孔子的旅游思想

孔子一生中有很长时间用在旅途上,远游经历对孔子思想体系的形成至关重要。他对来访的远游者持欢迎态度,也鼓励读书人主动走出去,提出了"游必有方"的远游思想,用"有方"来构建儒家伦理框架下的远游观。孔子的阐述常被后人有选择地误读,说明他的旅游思想具有创新性。孔子的旅游思想强调积极入世的人生价值观,包括"修学"、"游于政"等内容,也有一定的隐逸情调,为后世儒者向释道打开心灵之门预设了一种可能。孔子倡导的"游必有方"既注重实践过程,本身也是有效的教育手段,对道德修养和君子人格养成,具有重要的作用。     

边境旅游业在沿边地区扶贫中的作用

边境旅游作为一种特殊的旅游形式 ,其发展必将对沿边地区的经济发展发挥特殊的作用。以发展边境旅游业带动沿边地区脱贫致富 ,是近年来旅游部门主动参与扶贫工作的创举 ,也是从实践中总结出的推动旅游业深入发展的新思路。它不仅为我国经济欠发达的沿边地区经济发展和群众脱贫致富开辟了新的途径 ,也为我国旅游经济的持续发展找到了一个新的经济增长点。以边境旅游业的发展带动沿边地区经济的发展 ,是旅游业的一项重要功能。     

Static-dynamic uncertainty strategy for a single-item stochastic inventory control problem

We consider a single-stage inventory system facing non-stationary stochastic demand of the customers in a finite planning horizon. Motivated by the practice, the replenishment times need to be determined and frozen once and for all at the beginning of the horizon while decisions on the exact replenishment quantities can be deferred until the replenishment time. This operating scheme is refereed to as a “static-dynamic uncertainty” strategy in the literature [3]. We consider dynamic fixed-ordering and linear end-of-period holding costs, as well as dynamic penalty costs, or service levels. We prove that the optimal ordering policy is a base stock policy for both penalty cost and service level constrained models. Since an exponential exhaustive search based on dynamic programming yields the optimal ordering periods and the associated base stock levels, it is not possible to compute the optimal policy parameters for longer planning horizons. Thus, we develop two heuristics. Numerical experiments show that both heuristics perform well in terms of solution quality and scale-up efficiently; hence, any practically relevant large instance can be solved in reasonable time. Finally, we discuss how our results and heuristics can be extended to handle capacity limitations and minimum order quantity considerations.