The two-dimensional vector packing problem with piecewise linear cost function

The two-dimensional vector packing problem with piecewise linear cost function (2DVPP-PLC) is a practical problem faced by a manufacturer of children׳s apparel that ships products using courier service. The manufacturer must ship a number of items using standard-sized cartons, where the cost of a carton quoted by the courier is determined by a piecewise linear function of its weight. The cost function is not necessarily convex or concave. The objective is to pack all given items into a set of cartons such that the total delivery cost is minimized while observing both the weight limit and volume capacity constraints. This problem is commonly faced by many manufacturers that ship products using courier service. We formulate the problem as an integer programming model. Since the 2DVPP-PLC generalizes the classical bin packing problem, it is more complex and challenging. Solving it directly using CPLEX is successful only for small instances. We propose a simple heuristic that is extremely fast and produces high-quality solutions for instances of practical size. We develop an iterative local search algorithm to improve the solution quality further. We generate two categories of test data that can serve as benchmark for future research.     

The Association of Multiple Risk Factors With Fruit and Vegetable Intake Among a Nationwide Sample of College Students

Few college students meet fruit and vegetable intake recommended requirements, and most receive no information from their institutions about this issue. The avoidable disease burden among students is large, the necessary information infrastructure exists, and Healthy People 2010 objectives indicate efforts should be taken to increase intake. Objective: The authors examined the association of high-risk behaviors and fruit and vegetable intake to inform design of multiple risk factor interventions. Participants and Methods: The authors obtained data from a sample of 40,209 18- to 25-year-old college students who completed the American College Health Association-National College Health Assessment during the spring 2002 and 2003 semesters. Results: Predictors of high fruit and vegetable intake for men and women included better: seatbelt and helmet use, physical activity, perceived health, sleep, self-care behaviors, and grades. Other notable predictors of high intake were reduced likelihood of cigarette smoking, alcohol use, drinking and driving, and feeling hopeless in both sexes; reduced likelihood of drinking and driving among men; and a greater likelihood of anorexia among women. Conclusions: The authors discuss implications of these findings.     

绿色包装:我国的现状及对策

绿色包装是绿色革命和绿色运动的产物，适应了绿色消费需要的潮流。本文在介绍绿色包装的由来及其意义的基础上，重点分析了我国绿色包装产业发展中存在的问题，提出了发展我国绿色包装产业的对策，呼吁站在可持续发展的战略高度，大力发展绿色包装产业。     

中国书画艺术在包装设计中的运用与创新

中国的书画艺术是国粹.在包装设计中运用能形成我们的设计特色与个性,而且起到弘扬民族文化的重要作用.为了使中国书画艺术在包装设计中发挥更大的作用,应加强理论研究、人才培养、更新观念,促进中国书画在包装设计中不断发展与创新.     

中国水果产业国际竞争潜力评价及提升途径

改革开放以来,中国水果生产得到空前发展,水果业成为种植业中排在粮食、蔬菜之后的第三大产业,在国民经济中占有非常重要的地位。随着农产品市场国际化进程的加快,世界市场竞争日益激烈,中国水果产业必须不断提升自己的国际竞争力去迎接新的市场挑战。在考察一个国家水果产业的     

Determination of a Tolerable Daily Intake of DDT for Consumers of DDT Contaminated Fish from the Lower Yakima River, Washington*

DDT, DDE, and DDD have been detected at elevated concentrations in sediments and fish of the Yakima River, its tributaries and drainages. An assessment was conducted to evaluate the public health significance of eating fish from the river. This was accomplished by establishing a daily intake level of DDT for the population of greatest concern, and comparing this level to a tolerable daily intake. The most sensitive and highly exposed group was determined to be breastfeeding infants. Infant daily intakes of DDT, based on estimated mother's DDT-breast milk levels, were compared to a recommended tolerable daily intake. Results indicate that mothers who frequently consume Yakima River bottom-feeding fish could have breast milk DDT concentrations sufficiently high to expose their infants to levels above the tolerable daily intake.     

国外柑橘商品化处理的发展及其经验借鉴

发达国家柑橘产业实现了采后的大幅度增值,源于它们对商品化处理环节的重视。我国作为世界第三大柑橘生产国家,商品化处理产业刚开始起步,柑橘产后增值幅度很小,柑橘种植农户的收入也没有明显提高。本文先总结了国外发达国家柑橘商品化处理产业的发展经验,然后对我国柑橘商品化处理产业的发展提出了自己的对策和建议。     

A Review of the packing problem

The random pazking problem has been of interest to inoestigsccrs in seveal disciplines , Physical chemists have investigaced such models in two and three dimensions, Because of aralytical difficulties, one-dimensional analogacs have been explored and theseare referred to as the parking problem, A number of results areexplored and attempts are made to tie them together, Applicationsare also highlighted.     

黄金通衢拓市场 蔬果批发可增益

文章分析了在北仑区白峰镇兴建蔬菜果品批发市场的可能性及对该区、该镇经济发展的促进作用,最后提出了如何兴建该市场的具体建议。     

Packing of Unequal Spheres and Automated Radiosurgical Treatment Planning

We study an optimization problem of packing unequal spheres into a three-dimensional (3D) bounded region in connection with radiosurgical treatment planning. Given an input (R, V, S, L), where R is a 3D bounded region, V a positive integer, S a multiset of spheres, and L a location constraint on spheres, we want to find a packing of R using the minimum number of spheres in S such that the covered volume is at least V; the location constraint L is satisfied; and the number of points on the boundary of R that are touched by spheres is maximized. Such a packing arrangement corresponds to an optimal radiosurgical treatment planning. Finding an optimal solution to the problem, however, is computationally intractable. In particular, we show that this optimization problem and several related problems are NP-hard. Hence, some form of approximations is needed. One approach is to consider a simplified problem under the assumption that spheres of arbitrary (integral) diameters are available with unlimited supply, and there are no location constraints. This approach has met with certain success in medical applications using a dynamic programming algorithm (Bourland and Wu, 1996; Wu, 1996). We propose in this paper an improvement to the algorithm that can greatly reduce its computation cost.