基于弹性客流的城市轨道交通组合停站方案优化

为了解决城市轨道交通运输组织中的列车停站问题,考虑列车停站与客流换乘选择之间的主从博弈关系,建立了城市轨道交通组合型停站方案的0-1双层规划数学模型。上层停站模型以运营收益最大化为目标,以车站停站下限为约束;下层乘客路径选择以总旅行耗费时间最少为目标,乘车径路连续性和可行性为约束。根据双层规划模型特点分别对决策变量、目标函数和约束条件整合处理并通过优化软件求解。通过算例分析了参数的敏感度,并证明了模型的可行性和有效性。实例应用证明了组合停站更适用于特殊空间分布的客流。     

Optimal joint replenishment,delivery and inventory management policies for perishable products

In this paper we analyze the optimal joint decisions of when, how and how much to replenish customers with products of varying ages. We discuss the main features of the problem arising in the joint replenishment and delivery of perishable products, and we model them under general assumptions. We then solve the problem by means of an exact branch-and-cut algorithm, and we test its performance on a set of randomly generated instances. Our algorithm is capable of computing optimal solutions for instances with up to 30 customers, three periods, and a maximum age of two periods for the perishable product. For the unsolved instances the optimality gap is always small, less than 1.5% on average for instances with up to 50 customers. We also implement and compare two suboptimal selling priority policies with an optimized policy: always sell the oldest available items first to avoid spoilage, and always sell the fresher items first to increase revenue.     

A heuristic algorithm for cube packing with time schedule

Packing problem has been proved to be an NP-hard problem. Many algorithms such as simulation annealing algorithm, genetic algorithm and other heuristic algorithms have been proposed to solve twodimensional and three-dimensional packing problem. To solve the cube packing problem with time schedule, this paper first introduces some concepts such as packing level, space distance and average neighbor birth order and then proposes a greedy algorithm. The algorithm tries every feasible corner greedily to calculat...     

A replenishment policy for items with price-dependent demand,time-proportional deterioration and no shortages

In this article, an order-level inventory system for deteriorating items has been developed with demand rate as a function of selling price. The demand and the deterioration rate are price dependent and time proportional, respectively. We have considered a perishable item that follows a three-parameter Weibull distribution deterioration. Shortages are not permitted in our model. The optimal solution is illustrated with a numerical example and the sensitivity analysis of parameters is carried out.     

基于订单更改的间歇多产品厂调度在线调整研究

针对间歇化工厂产品市场变化快的特点,提出了基于订单更改的多产品厂调度在线调整模型：该模型根据生产进度对产品进行分类,并结合原调度采取相应的调整策略,得到满意的调整方案。模型基于原调度,不需增加太多变量,故在建模和实际应用中易于实现。文中将该模型用于无限中间储罐的间歇多产品厂调度在线调整实例,并通过调度调整方案对订单更改时刻的灵敏度分析找出了目标函数的影响因素。     

Efficient operation of natural gas transmission systems: A network-based heuristic for cyclic structures

In this paper we propose a heuristic solution procedure for fuel cost minimization on gas transmission systems with a cyclic network topology, that is, networks with at least one cycle containing two or more compressor station arcs. Our heuristic solution methodology is based on a two-stage iterative procedure. In a particular iteration, at a first stage, gas flow variables are fixed and optimal pressure variables are found via dynamic programming. At a second stage, pressure variables are fixed and an attempt is made to find a set of flow variables that improve the objective function by exploiting the underlying network structure. Empirical evidence supports the effectiveness of the proposed procedure outperforming the best existing approach to the best of our knowledge.     

现代家居设计中小户型怎样合理利用空间

楼市新政对楼盘户型进行了限制调整,小户型已经成为相当一部分人的居住常态,如何充分利用小小的空间,发挥小户型灵巧的优势,打造一个既温馨又有个性的小世界呢?怎样才能在小空间里做出"大文章"呢?其实,房间虽小,只要用心设计和装饰,一样能收到功能、美观两不误的效果。设计师通过巧妙的设计、合理地运用材质、多功能家具的使用以及颜色的调配等各种手段解决了小户型装修的多个难题。     

实现操作系统安全的几种策略

操作系统作为计算机系统中最重要的软件，其安全在整个信息安全领域内显得尤为重要。本文以操作系统需要保护的对象为线索，提供了几种操作系统的安全策略。     

Labyrinth, an abstract model for hypermedia applications. Description of its static components

In information technology, models are abstract devices to represent the components and functions of software applications. When a model is general and consistent, it represents a useful design tool to unambiguously describe the application. Traditional models are not suitable for the design of hypermedia systems and, therefore, specific design models and methodologies are needed. In the present article, the requirements for such models are analysed, an overview of the characteristics of the existing models for hypermedia applications is made and an abstract model fulfilling the analysed requirements is presented. The model, called Labyrinth, allows 1) the design of platform-independent hypermedia applications; 2) the categorisation, generalisation and abstraction of sparse unstructured heterogeneous information in multiple and interconnected levels; 3) the creation of personalisations (personal views) in multiuser hyperdocuments for both groups and individual users and 4) the design of advanced security mechanisms for hypermedia applications.     

Influences of the 'social contract', technology and restructuring,and training on the supply and demand for skilled technology workers

This article is designed to trace the forces influencing the supply and demand for 'knowledge workers'. The effects of technology and restructuring are the most important from industry's standpoint in influencing demand because industry as a whole 'does not do enough' training to help in the supply, based on the comments of experts. The incentives provided by industry through the 'social contract' with workers, as discussed, are as essential as training in affecting the supply of these workers. But because industry does not want to train unless there is a condition of payback in its investment in training, such preparation is left to the high schools and colleges. Thus school-to-work transitions are needed as an important part of what high schools and colleges should offer.     

基于行为场所理论的居住区设计分析——以水木天成为例

文章以行为场所理论为切入点,选取了居住小区环境中的多个具体典型场所,分析了在设计居住区环境时,应考虑居民的行为和心理,从而创造出符合现代生活模式,适合各种人群行为及心理需要的室外活动场所和交往空间。     

Fusion of color, local spatial and global frequency information for face recognition

This paper presents a novel face recognition method by means of fusing color, local spatial and global frequency information. Specifically, the proposed method fuses the multiple features derived from a hybrid color space, the Gabor image representation, the local binary patterns (LBP), and the discrete cosine transform (DCT) of the input image. The novelty of this paper is threefold. First, a hybrid color space, the RC_rQ color space, is constructed by combining the R component image of the RGB color space and the chromatic component images, C_r and Q, of the YC_bC_r and YIQ color spaces, respectively. The RC_rQ hybrid color space, whose component images possess complementary characteristics, enhances the discriminating power for face recognition. Second, three effective image encoding methods are proposed for the component images in the RC_rQ hybrid color space to extract features: (i) a patch-based Gabor image representation for the R component image, (ii) a multi-resolution LBP feature fusion scheme for the C_r component image, and (iii) a component-based DCT multiple face encoding for the Q component image. Finally, at the decision level, the similarity matrices generated using the three component images in the RC_rQ hybrid color space are fused using a weighted sum rule. Experiments on the Face Recognition Grand Challenge (FRGC) version 2 Experiment 4 show that the proposed method improves face recognition performance significantly. In particular, the proposed method achieves the face verification rate (ROC III curve) of 92.43%, at the false accept rate of 0.1%, compared to the FRGC baseline performance of 11.86% face verification rate at the same false accept rate.