Using the Pack‐and‐a‐Half Rule to Eliminate Backroom Inventories in Retail Operations

In the retail industry, backroom inventories are typically associated with higher labor costs and greater operational complexity. Thus, retailers look for ways to eliminate backroom inventories. A heuristic used for this purpose is the pack‐and‐a‐half rule which suggests that the shelf space allocated for a product should be at least 50% larger than the case pack quantity in which the product is delivered. Despite its popularity among retailers, the pack‐and‐a‐half rule has been ignored in the academic literature. We introduce the pack‐and‐a‐half rule, assess its impact on a retailer's profits, identify cost, demand, and product characteristics driving this impact, and propose a modification. Based on an analysis of data obtained from a retailer on 1,986 SKUs in 20 categories, we find that the pack‐and‐a‐half rule decreases a retailer's profits, on average, by 10% when applied uniformly across all SKUs. Further, this decrease is significantly affected by product depth, product width, demand elasticity, case pack quantity, and inventory carrying cost. Finally, we develop a set of modifications based on these variables where the pack‐and‐a‐half rule is applied selectively and in a stepwise fashion. These modifications limit the decrease in a retailer's profits to a range between 6% and 7%.     

终身学习视角下公共图书馆的转型与发展思考

公共图书馆作为公共文化服务体系的重要组成部分,在构建学习型社会的大背景下,为促进终身学习的理念,借鉴国外图书馆的前沿探索,提升人文素质和知识内涵,实现公共图书馆在新的历史形势下自身的转型与发展。     

ZY5000/15/32掩护式液压支架的优化设计

当支架工作一定时间后出井维护时,需要将前梁与顶梁之间的销轴拿掉后改为运输销轴连接,由于井底空间、设备有限,操作极为不便;另外,由于前梁千斤顶是靠销轴受力,因为支架工作时间比较长且井下环境恶劣,导致销轴出现变形、生锈等现象,以致销轴不易拆卸。     

基于多重交叉残差方法的空间目标旋转特性分析

针对传统的频谱分析和自相关函数反演周期时常出现虚假周期的问题，提出了多重交叉残差法处理空间旋转目标雷达散射截面(Radar Cross Section，RCS)的时间序列。以空间跟踪和监视系统(Space Tracking and Surveillance System,STSS)卫星为例，仿真了空间目标失稳旋转状态，对比了频谱分析、自相关函数和多重交叉残差3种方法的处理结果，发现当目标存在进动运动时多重交叉残差法抗干扰能力更强。在此基础上，进一步研究了不同章动角时多重交叉残差法对旋转周期的反演效果，结果表明章动角大小会影响旋转周期的反演准确度，且章动角达到一定数值后，卫星进动幅度过大导致RCS序列周期性模糊，无法用多重交叉残差法反演出旋转周期。     

土壤污染防治法背景下的城乡绿地系统建设：趋势与对策

《中华人民共和国土壤污染防治法》的颁布标志着中国将形成完善的土壤污染防治法律体系，建立从污染土壤调查、修复、风险防控、监测到场地再利用，从环境标准到规划管理的全方位制度。生态文明制度建设的宏观背景，再加上中国土壤污染严重、规模大、修复难、成本高、周期长等特征，将导致大量污染场地转变为绿地或生态用地，最终对绿地系统的数量与规模、布局与功能、规划与管理、环境质量标准等多个维度产生实质性影响。分析这一趋势，对其影响提出预判，最终提出对策建议。     

When was the U.S. housing downturn predictable? A comparison of univariate forecasting methods

This paper uses three classes of univariate time series techniques (ARIMA type models, switching regression models, and state-space/structural time series models) to forecast, on an ex post basis, the downturn in U.S. housing prices starting around 2006. The performance of the techniques is compared within each class and across classes by out-of-sample forecasts for a number of different forecast points prior to and during the downturn. Most forecasting models are able to predict a downturn in future home prices by mid 2006. Some state-space models can predict an impending downturn as early as June 2005. State-space/structural time series models tend to produce the most accurate forecasts, although they are not necessarily the models with the best in-sample fit.     

国土空间多功能利用效益评价——以广东省汕头市为例

进行汕头市国土空间多功能利用效益评价,为汕头市科学利用土地,进行国土规划、提高国土利用效率奠定前提和基础。以可持续发展为目的,结合汕头市自然社会发展特点及国土空间利用现状,从社会、经济、资源与生态环境4个功能为切入点,建立4个功能层10个准则层27个指标的国土空间多功能利用效益评价指标体系,并采用熵值法对各功能进行评分。研究结果显示:汕头市国土空间经济功能评分最高,为汕头市国土空间主导功能,其次是经济、资源、环境功能,但社会、文化等功能较弱,各功能缺乏平衡。15年来,汕头市国土空间评价总体评分不断提高,表明国土利用效益在持续提高,但各功能发展不均衡以及人地矛盾依然突出,需要不断加强和完善国土空间规划。     

In and out of everyday life through film experiences: an analysis of two social spaces as leisure frames

The new information and communication technologies have made it possible to view films in different spaces. Using the symbolic interactionist framework as a frame of analysis, we interpret the meaning of the two experiences of viewing technology-mediated films in the home and in the cinema. We conducted field research during the first half of 2009, digitally recording 16 interviews with research participants living in Barcelona (Spain). The interviews were transcribed verbatim with the help of voice-recognition software. Reports from our research participants indicate that individuals considered only the cinema experience to be a true leisure activity, while the home experience was interpreted as a routine recreational activity. Therefore, the meanings of the film-viewing activity were associated with the symbolic properties of the frames of interpretation. Finally, we discuss the implications of these findings for the home as a unified centre where shared meanings are co-produced by family members.     

转型期中国土地利用的时序优化与空间释放

随着中国经济快速发展和人口集聚，建设用地需求快速增加，土地供需矛盾日益突出，资源保护和管理的压力逐渐加大。中国经济已步入新常态，经济结构转型倒逼土地供应结构优化调整。发达国家城镇化发展阶段起步较早，在土地节约集约利用与管理方面积累了宝贵经验。结合中国城市土地利用现状，借鉴美国、英国、德国等发达国家土地利用与管理经验，可从盘活存量土地、提高土地供给精准度、建立多元化供地机制三方面实现土地节约集约利用及有效管理，促进供给侧结构性改革。     

统筹城乡的建设用地空间重构机制与对策研究

统筹城乡发展要求重构建设用地空间。分析了我国土地政策促进城乡统筹的现实困境,表现为城乡用地供需错位、土地要素缺乏流动性、置换指标区际交易机制不健全、收益共享机制不完善等;以此为基础,从农村建设用地整理模式转换、置换指标跨县区流转、土地增值收益共享、规划引导4个方面构建了统筹城乡的建设用地空间重构机制;并提出要加强土地政策与相关政策的衔接,强化监管及保障体系建设,以充分发挥土地政策的宏观调控作用。