基于可持续社区建构的城市公共服务设施配置方法——以成都市新都城区为例

针对中国当前以市场为主导的 住区建设中原有基于“组团—小区—居住 区”城市住区层次架构的公共服务设施 配置方法失效问题,运用美国新城市主 义TND模型和英国可持续邻里相关理 论,结合成都市新都城区实际,提出基于 可持续社区建构的城市公共服务设施配 置思路,进而建构出由“划分社区类型— 建立社区层次—探寻公共服务设施布局 形态—分级配置”所组成的城市公共服 务设施配置方法。     

上海光源前端高热负载挡光器的结构设计与优化

为了有效处理上海光源前端挡光器接收的高热负载,研究了挡光器的结构设计及其优化方法。选用高导热性、高强度的GlidCop AL-15制造挡光器吸收体,采用直接水冷和掠入射结构提高其热缓释能力。以对流换热系数和压力降为评价指标,选用佩图克方程和达尔西-韦斯巴赫方程优化冷却水路,通过热分析得到了不同参数下挡光器的温度和热应力分析结果,从而确定了挡光器的结构设计优化参数。优化后挡光器的水路直径为6mm,水路到光照面的距离为9mm,光照面接线处圆角≥2mm,且水路与光束方向基本平行。与初始结构相比,优化后挡光器的最高整体温度和最高冷却壁温度分别下降约8%和1/4,最大等效应力降低了1/2左右,完全满足上海光源前端部件的设计要求。目前,应用优化参数设计的挡光器已应用于上海光源实际工程中。     

An analytical method to evaluate facility management services for residential buildings

Besides constructed quality and environmental quality, the quality of facilities in residential buildings is influential to the living quality of numerous residents there. The functional quality of the facilities, in turn, is dependent on the quality of their operation and management. A review of the relevant literature and a focus group discussion with Facility Management (FM) practitioners, which were parts of the study reported here, unveiled that prior performance evaluation studies focussed on assessing the outcome of FM services whereas an analytical method suitable for holistic evaluation of the services is lacking. An interview survey with 297 users of a typical residential estate in Hong Kong was carried out to solicit their perceived levels of importance and performance of FM services. The responses were tested using the Analytical Hierarchy Process (AHP) to isolate those with inconsistent judgments, followed by computing the weightings for various aspects of FM services based on the consistent responses. The calculation of a weighted performance score for benchmarking purposes and a critical evaluation of the cost-effectiveness of FM services, which are crucial for achieving a quality and sustainable built environment, are illustrated.     

Pellet production from agricultural raw materials - A systems study

The demand for biofuel pellets has increased considerably in recent years, causing shortage of the traditional raw materials sawdust and wood shavings. In this study, the costs and energy requirements for the production of pellets from agricultural raw materials were analysed. The materials studied were Salix, reed canary grass, hemp, straw, screenings, rape-seed meal, rape cake and distiller’s waste. Four production scales were analysed, having an annual output of 80,000, 8000, 800 and 80 tonnes of pellets per year. It was concluded that the raw materials of greatest interest were Salix and reed canary grass. They had competitive raw material costs and acceptable fuel properties and could be mixed with sawdust in existing large-scale pelleting factories. Straw had low production costs but can cause serious ash-related problems and should, as also is the case for screenings, be avoided in small-scale burners. Hemp had high raw material costs and is of less commercial interest, while distiller’s waste, rape-seed meal and rape cake had higher alternative values when used as protein feed. The scale of production had a crucial influence on production costs. The machinery was used much more efficiently in large-scale plants, resulting in clear cost savings. Small-scale pelleting, both static and mobile, required cheap raw materials, low labour costs and long utilisation times to be profitable. In most cases, briquetting would be more commercially viable. The energy use in manufacturing pellets from air-dried crops was generally no higher than when moist sawdust was used as the raw material.     

Sequential versus simultaneous approach in the location and design of two new facilities using planar Huff-like models

Companies frequently decide on the location and design for new facilities in a sequential way. However, for a fixed number of new facilities, the company might be able to improve its profit by taking its decisions for all the facilities simultaneously. In this paper we compare three different strategies: simultaneous location and independent design of two facilities in the plane, the same with equal designs, and the sequential approach of determining each facility in turn. The basic model is profit maximization for the chain, taking market share, location costs and design costs into account. The market share captured by each facility depends on the distance to the customers (location) and its quality (design), through a probabilistic Huff-like model. Recent research on this type of models was aimed at finding global optima for a single new facility, holding quality fixed or variable, but no exact algorithm has been proposed to find optimal solutions for more than one facility. We develop such an exact interval branch-and-bound algorithm to solve both simultaneous location and design two-facility problems. Then, we present computational results and exhibit the differences in locations and qualities of the optimal solutions one may obtain by the sequential and simultaneous approaches.     

A real-time agro-food authentication and supervision system on a novel code for improving traceability credibility

Counterfeiting products and abusing labels lead to less credibility for traceability system in China recently. Authentication and supervision agencies driven by government departments play an important role for ensuring the quality safety in the case of lacking the willingness and credit of enterprises. A complete authentication and supervision flow framework was constructed based on an identification code (IdC) for authenticated origin base, which linked two actors of the agencies and the enterprises, and three subsystems of On-line Authentication Subsystem (OAS), Safety Production Management Client (SMC) and Mobile Supervision Application (MSA). IdC consisted of longitude and latitude of origin base as position code, production code and authentication type code. With a relative position partition method on 6 zones every 27° for China map and a coordination transformation algorithm, an absolute longitude and latitude value was converted into a relative position value and a zone mark value. IdC and packaging date code formed initial traceability code (TC). 8 digits packaging date code was reconstructed into 3 digits relative time value and 1 digit period mark according to a relative time period partition method with a period of 999d as time intervals and four periods form a cycle. Validation code was generated integrating the zone mark value, period mark value and authentication type code. Therefore, transformed 20 digits TC with the characters of shorter code length and stronger encryption was formed with IdC, relative time value and validation code. Three subsystems for different actors which provide the main function such as origin base registration, agency authentication, QR code generation, data uploading and product verification, were developed. The system has been used in Tianjin city from 2012. 213 enterprises were audited through OAS and used SMC. Through investigating 8 supervision agency staffs, 30 origin base owners, and 50 customers, it is shown that the positive effects are approved by most of the investigators and two negative effects for enhancing the costs and doubting the authentication reliability are laid by 17 enterprises and 12 customers. Furthermore, 4 typical cases for counterfeiting and abusing the labels were exampled and can be solved to a certain extent with the system. However, except for the technology itself, a management measures fitting the supervision flow and system need to draft in order to improve the system application well in the future.     

Image-based atmospheric correction of QuickBird imagery of Minnesota cropland

High spatial resolution QuickBird satellite data have provided new opportunities for remote sensing applications in agriculture. In this study, image-based algorithms for atmospheric correction were evaluated on QuickBird imagery for retrieving surface reflectance (ρ_λ) of corn and potato canopies in Minnesota. The algorithms included the dark object subtraction technique (DOS), the cosine approximation model (COST), and the apparent reflectance model (AR). The comparison with ground-based measurements of canopy reflectance during a 3-year field campaign indicated that the AR model generally overestimated ρ_λ in the visible bands, but underestimated ρ_λ in the near infrared (NIR) band. The DOS-COST model was most effective for the visible bands and produced ρ_λ with the root mean square errors (RMSE) of less than 0.01. However, retrieved ρ_λ in the NIR band were more than 20% (mean relative difference or MRD) lower than ground measurements and the RMSE was as high as 0.16. The evaluation of the COST model showed that atmospheric transmittance (T_λ^θ) was substantially overestimated on humid days, particularly for the NIR band because of the undercorrection of water vapor absorption. Alternatively, a contour map was developed to interpolate appropriate T_λ^θ for the NIR band for clear days under average atmospheric aerosol conditions and as a function of precipitable water content and solar zenith angle or satellite view angle. With the interpolated T_λ^θ, the accuracy of NIR band ρ_λ was significantly improved where the RMSE and MRD were 0.06 and 0.03%, respectively, and the overall accuracy of ρ_λ was acceptable for agricultural applications.     

An LP rounding algorithm for approximating uncapacitated facility location problem with penalties

In this paper, we consider an interesting variant of the facility location problem called uncapacitated facility location problem with penalties (UFLWP, for short) in which each client can be either assigned to some opened facility or rejected by paying a penalty. Existing approaches [M. Charikar, S. Khuller, D. Mount, G. Narasimhan, Algorithms for facility location problems with outliers, in: Proc. Symposium on Discrete Algorithms, 2001, p. 642] and [K. Jain, M. Mahdian, E. Markakis, A. Saberi, V. Vazirani, Greedy facility location algorithms analyzed using dual fitting with factor-revealing LP, J. ACM 50 (2003) 795] for this variant of facility location problem are all based on primal-dual method. In this paper, we present an efficient linear programming (LP) rounding based approach to show that LP rounding techniques are equally capable of solving this variant of facility location problem. Our algorithm uses a two-phase filtering technique (generalized from Lin and Vitter's [?-approximation with minimum packing constraint violation, in: Proc. 24th Annual ACM Symp. on Theory of Computing, 1992, p. 771]) to identify those to-be-rejected clients and open facilities for the remaining ones. Our approach achieves an approximation ratio of 2+2/e (≈2.736) which is worse than the best approximation ratio of 2 achieved by the much more sophisticated dual fitting technique [K. Jain, M. Mahdian, E. Markakis, A. Saberi, V. Vazirani, Greedy facility location algorithms analyzed using dual fitting with factor-revealing LP, J. ACM 50 (2003) 795], but better than the approximation ratio of 3 achieved by the primal-dual method [M. Charikar, S. Khuller, D. Mount, G. Narasimhan, Algorithms for facility location problems with outliers, in: Proc. Symposium on Discrete Algorithms, 2001, p. 642]. Our algorithm is simple, natural, and can be easily integrated into existing LP rounding based algorithms for facility location problem to deal with outliers.     

Performance-Based Optimization of Land and Water Resources within Irrigation Schemes. II: Application

The area and water allocation model which uses simulation–optimization technique for optimum allocation of land and water resources to different crops cultivated in different allocation units of the irrigation scheme was modified to include both productivity and equity in the process of developing the allocation plans for optimum productivity and/or maximum equity. This paper illustrates the potential of this approach with the help of a case study on Nazare medium irrigation scheme in India. The allocation plans were developed for optimization of different performance parameters (productivity and equity) for different management strategies based on irrigation amount and irrigation interval and cropping distribution strategies of free and fixed cropping. The results indicated that the two performance objectives productivity and equity conflict with each other and in this case, equitable water distribution may be preferred over free water distribution at the cost of a small loss in productivity. Though these results relate to one case study, they show the value of the approach of incorporating productivity and equity in the allocation process with the help of the simulation-optimization model described in the companion paper.     

浅析提高标准节流装置在计量中的准确性

介绍柳钢使用的标准节流装置计量系统，并对设计、安装、维护的特点进行探讨，保证节流式流量计的正常运行。