Improved Approximation for Breakpoint Graph Decomposition and Sorting by Reversals

Sorting by Reversals (SBR) is one of the most widely studied models of genome rearrangements in computational molecular biology. At present, is the best known approximation ratio achievable in polynomial time for SBR. A very closely related problem, called Breakpoint Graph Decomposition (BGD), calls for a largest collection of edge disjoint cycles in a suitably-defined graph. It has been shown that for almost all instances SBR is equivalent to BGD, in the sense that any solution of the latter corresponds to a solution of the former having the same value. In this paper, we show how to improve the approximation ratio achievable in polynomial time for BGD, from the previously known to for any > 0. Combined with the results in (Caprara, Journal of Combinatorial Optimization, vol. 3, pp. 149–182, 1999b), this yields the same approximation guarantee for n! – O((n – 5)!) out of the n! instances of SBR on permutations with n elements. Our result uses the best known approximation algorithms for Stable Set on graphs with maximum degree 4 as well as for Set Packing where the maximum size of a set is 6. Any improvement in the ratio achieved by these approximation algorithms will yield an automatic improvement of our result.     

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.     

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.     

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.     

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.     

从中文文学期刊的特色谈其风格演变及发展变化

在图书馆的藏书中,中文期刊占有很大比重,其中中文文学期刊又占据期刊榜首。探究其发展规律,为到馆的读者更好服务有着很深的意义。中文文学期刊在动乱结束后,曾迎来繁荣发展的大时代,满足了当时人们对其的渴望,中文文学期刊在当时为数不多的大众文化产品的中占有相当的地位。而今社会是信息产业的多样化,数字化,视觉化的多元时代,中文文学期刊受到不小冲击,为了寻求出路,必须走出低谷。从自身改变中寻求新的发展．探求发展变化中的规律,这些发展主要表现在多元化的包装,文学期刊与影视互动。为影视作品提供创作蓝本等等．为中文文学期刊适应当今社会发展奠定了基础。     

Almost optimal solutions for bin coloring problems

In this paper we study two interesting bin coloring problems: Minimum Bin Coloring Problem (MinBC) and Online Maximum Bin Coloring Problem (OMaxBC), motivated from several applications in networking. For the MinBC problem, we present two near linear time approximation algorithms to achieve almost optimal solutions, i.e., no more than OPT+2 and OPT+1 respectively, where OPT is the optimal solution. For the OMaxBC problem, we first introduce a deterministic 2-competitive greedy algorithm, and then give lower bounds for any deterministic and randomized (against adaptive offline adversary) online algorithms. The lower bounds show that our deterministic algorithm achieves the best possible competitive ratio. The research of this paper was partially supported by an NSF CAREER award CCF-0546509.     

包装设计可持续性发展要素研究

设计作为一种生产力,对每一个国家地区经济发展有着重要的推动作用,也是整个社会物质文明和精神文明的结晶,是一个国家科学和文化发展的重要标志。当今社会人们越来越注重设计所带来的产品附加值,但是在观念上,却存在很大的误区,造成了过度包装、环境污染、低级媚俗、盲目模仿等不健康的设计现象。如何把包装审美和产业价值与环境保护有机结合,这是当今学术界关心的焦点,也是包装产业新的增长点。同时包装材料生产工艺、减少环境污染也成为全人类共同关心的话题,寻找新材料、新工艺,最大限度降低环境的人为污染,防止产品附加值对环境造成的二次污染,也成为包装行业当前共同努力研究的紧迫课题。文章针对包装设计存在的上述问题,剖析了产生这些现象的原因。着重从包装设计的民族化、人性化、非物质性、绿色化四个方面,论证了包装设计寻求可持续性发展应具备的重要条件,并提出了解决这些问题的应对方案,有助于树立健康的包装设计理念,有助于包装设计向着可持续性方向健康发展。     

“包装意识”在期刊编校质量中的作用

期刊的质量是一个系统工程 ,必须注重期刊内在质量系统与外在质量系统的辩证统一。期刊的编校质量在期刊外在质量系统中占有重要地位 ,编校水平的高低直接影响期刊的质量。期刊的外在质量系统具体体现在编辑的包装意识中。编辑的“包装意识”决定了期刊的编校质量