Packing items to feed assembly lines

We treat a practical application of packing problems in feeding assembly lines. This study was motivated by a real situation encountered in the shop floor of a major automobile industry plant in Brazil. The assembly line feed problem (LFP) consists in how pack the items in the available containers to meet the line work centers’ requirements with a minimum total cost over the planning horizon. LFP is a variable-sized bin packing problem that has two special features: (i) a cardinality constraint on each bin’s size; and, (ii) a cost structure such that each bin’s cost varies according to the items that are packed in it. We propose an integer programming model and a GRASP heuristic for LFP. Numerical results on real-life test instances are reported.     

On Cyclic Packing of a Tree

We prove that there exists a packing of copies of a tree of size into K_n. Moreover, the proof provides an easy algorithm.Acknowledgments. The research of the second author was partially supported by Deutscher Akademischer Austauschdienst.     

货物尺寸相同的2维装箱问题的等价类(英文)

在生产与储运领域,把小长方体货物（盒子）装入大长方体箱子是一项重要的工作.本文涉及的问题是:把相同尺寸（a×b×c）的盒子装到一个箱子X×Y×Z中,使所装入箱子的盒子数量为最大.由于某些条件的限止,有时要求货物只能按一个重力方向进行装箱,从而使装箱问题变为把尺寸相同的2维盒子（a×b）填装到一个2维箱子X×Y中.本文讨论当盒子尺寸（a×b包括 b×a）给定,箱子尺寸充分大时,在本文所给的等价意义下,共有多少种互不等价的箱子X×Y.     

一种包装膜的ATR-FTIR的剖析

在FTIR中,使用透射谱及水平ATR对进口的一种包装膜进行分析,该膜的厚度大约为0.034m/m,膜的两面分别由等规聚丙烯和聚对苯二甲酸乙二醇酯组成。     

An emergent computation approach to the problem of polygon layout with performance constraints

We address the two-dimensional satellite irregular polygons layout problem (TDSIPLP). By mapping the layout problem to a physical system, we present a self-organization emergence algorithm (SEA) based on a multi-agent system (MAS). SEA uses information on the local energy of agents and neighborhood rules to guide interactions between the agents and the environment. System self-organization evolves at a microcosmic level and eventually yields a layout that meets the performance constraints for a satellite. Experiments show that SEA can provide much better performance than other optimization techniques, such as generalized simulated annealing (GSA).     

Efficient approaches for furnace loading of cylindrical parts

This paper addresses the heat treatment operation in a manufacturing plant that produces different types of cylindrical parts. The immediate prior process to heat treatment is furnace-loading, where parts are loaded into baskets. The furnace-loading process is complex and involves issues relating to geometry, and heterogeneity in the parts and in their processing requirements. Currently, furnace-loading is accomplished by operator ingenuity; consequently, the parts loaded in heat treatment often do not use furnace capacity adequately. Efficiency in furnace operation can be achieved by improving basket utilization, which is determined by the furnace-loading process. This paper describes the development of integer and mixed integer LP models for 3D loading of cylindrical parts into furnace baskets. The models consider the exact location of parts to be loaded on the basket and incorporate three models with different objectives; the first addresses the nesting of parts within one another, the second addresses the number of basket layers used, and the third addresses the number of baskets used.     

A block-based layer building approach for the 2D guillotine strip packing problem

We examine the 2D strip packing problems with guillotine-cut constraint, where the objective is to pack all rectangles into a strip with fixed width and minimize the total height of the strip. We combine three most successful ideas for the orthogonal rectangular packing problems into a single coherent algorithm: (1) packing a block of rectangles instead of a single rectangle in each step; (2) dividing the strip into layers and pack layer by layer; and (3) unrolling and repacking the top portion of the solutions where usually wasted space occurs. Computational experiments on benchmark test sets suggest that our approach rivals existing approaches.     

Reducing Packing Factor of ZnIn2S4 to Promote Photocatalytic Activity

Due to the quite sluggish charge-carrier separation in semiconductor photocatalysts, the photocatalytic activity of these materials is still far inferior than anticipated. Herein, a novel approach to reducing the packing factor(PF) of ZnIn₂S₄ semiconductors to improve the charge-carrier separation is offered. The well-crystallized Zn_1-xIn₂S_4-x(x=0, 0.05, 0.1) powders were productively prepared through solid-state reactions. Their structures were verified by the high-resolution transmission electron microscopy, powder X-ray diffraction, and X-ray photoelectron spectroscopy. The PF values of Zn_1-xIn₂S_4-x(x=0, 0.05, 0.1) samples were calculated to be 0.683, 0.651, and 0.618, respectively. The reduction of the PF for Zn_1-xIn₂S_4-x with increasing x can promote the separation of photoexcited carriers, and this process was endorsed by their photoelectric response and photoluminescence emission spectra. The Zn_0.9In₂S_3.9 sample with a lower PF value presents roughly 21 times higher photocurrent density and four times higher photodegrading rate of methyl orange than those of pristine ZnIn₂S₄.     

概率空间上有限测度的维数及其分布

设（Ω，Ｆ，μ）为概率空间，ｖ为（Ω，Ｆ）上的有限测度的密度定理，并研究了ｖ的维数及维数分布的若干性质。     

两个三角形不相交的充要条件

判断平面上两个三角形是否相交是求解三角形Packing问题的一种基本操作 .本文提出了两个三角形不相交的一个充要条件 ,并将不相交判别法与相交判别法作了比较 ,比较结果表明不相交判别法比相交判别法在计算速度上有根本的改善 .