Solid Waste Collection: A Case Study

Planning for urban solid waste management requires an assessment of many complex interactions among transportation systems, land use patterns, urban growth and development, and public health considerations. The authors discuss the application of a data acquisition and analysis system and a simulation model to the complex problems of the solid waste management system in Cleveland, Ohio. As the result of applying these techniques, Cleveland's solid waste managers reduced their annual budget of $14.8 million in 1970 to a low of $8.8 million in 1972. The total savings in a 3-yr period were $14.6 million based on the 1970 budget. In addition, the city reduced its solid waste work force from 1640 to 850 and the number of collection routes from 224 to 102, and it redesigned its collection routing system. The management structure of the Division of Solid Waste Collection and Disposal was completely reorganized to take advantage of and to supplement these major organizational changes. The City Council has, moreover, passed an ordinance which will allow the construction of transfer stations, as recommended in the study; one such facility has been built, and land has been purchased for the other.     

THE ROLE OF GROUNDWATER‐DEPENDENT ECOSYSTEMS IN GROUNDWATER MANAGEMENT

Ecosystems provide a wide range of services essential for a proper environmental, economic, and social performance. While the estimated global value of ecosystem services in 2014 is very significant, the annual loss of ecosystem services value is alarming. Our paper focuses on groundwater‐dependent ecosystems (GDEs), some very important to society, which are under threat due to groundwater overexploitation. Considering the ecosystem health/status function is essential for sound groundwater regulation policy. The paper assesses the conjunctive management of groundwater and GDEs both in theory and in a relevant case study, using a certain type of an ecosystem health function. The theoretical results demonstrate how the change in the slope values of a general ecosystem health function affects the optimal groundwater management policy. The analysis also suggests a change in groundwater management strategies as a function of the value of the ecosystem. The theoretical findings are corroborated with data from an aquifer in Spain and its associated GDE—the Tablas de Daimiel Wetland. The paper highlights theoretically and empirically the necessity for a better understanding of GDEs behavior. It calls for groundwater regulation to protect these resources.     

Set pair analysis for urban ecosystem health assessment

Set pair analysis (SPA) is introduced to assess the urban ecosystems, through which the approximate degree of urban ecosystem health to the optimal set is calculated to describe the health level of the urban ecosystems by combining multiple health indices. The urban ecosystem health levels of Beijing, Dalian, Shanghai, Wuhan, Xiamen and Guangzhou from 1995 to 2003 are thereafter evaluated using SPA. The results show that the urban ecosystem health states of Xiamen and Guangzhou is the best during the study period, while the health states of the others changes over time. Particularly, the change of Beijing’s urban ecosystem health from 1992 to 2003 is analyzed in detail.     

An agent-based approach for structured modeling,analysis and improvement of safety culture

Safety culture is broadly recognized as important for operational safety in various fields, including air traffic management, power plant control and health care. Previous studies addressed characterization and assessment of safety culture extensively. Nevertheless, relations between safety culture and formal and informal organizational structures and processes are yet not well understood. To address this gap, a new, formal, agent-based approach is proposed. This paper shows the application of the approach to an air navigation service provider, including structured modeling, analysis and identification of improvement strategies for the organizational safety culture. The model results have been validated using safety culture data that had been achieved by an independent safety culture survey study.     

Service network design models for two-tier city logistics

This paper focuses on two-tier city logistics systems for advanced management of urban freight activities and, in particular, on the first layer of such systems where freight is moved from distribution centers on the outskirts of the city to satellite platforms by urban vehicles, from where it will be distributed to customers by a different fleet of dedicated vehicles. We address the issue of planning the services of this first tier system, that is, select services, their routes and schedules, and determine the itineraries of the customer-demand flows through these facilities and services. We propose a general scheduled service network design modelling framework that captures the fundamental concepts related to the definition of urban-vehicle tactical plans within a two-tier distribution network. We examine several operational assumptions regarding the management of the urban-vehicle fleet and the flexibility associated with the delivery of goods, and show how the proposed modelling framework can evolve to represent an increasing level of detail. A discussion of algorithmic perspectives completes the paper.     

城市CIS物理关联脆弱性的动态分析方法

本文以城市关键基础设施系统(Critical Infrastructure System, CIS)为研究对象,将关键基础设施之间组成的复杂物理网络划分为个体层面、中观层面和系统层面三种类型,从物理关联势差的角度分析了城市CIS内部物理关联机理。根据城市CIS物理关联特性,引入元胞自动机(Cellular Automata, CA),以一种物理资源为主导建立模型,采用“自底向上”的方法,从微观关键基础设施活动推出宏观城市CIS表现。选取元胞连通性、元胞正常状态变化率和传输效率作为脆弱性评估指标,估算不同时间点城市CIS脆弱性的动态变化,实现物理关联脆弱性的动态分析,并运用加权平均值作为一段时间内城市CIS脆弱值。最后,以S城市为例,对物理关联脆弱性动态分析方法的合理性和有效性进行验证,评估结果为城市CIS保护提供支持。     

Urban dynamics and multiple-objective programming: A case study of Beijing

This study serves as a primary application of the integrated system dynamics and multiple-objective programming (ISDMOP) model for strategic planning of Beijing city, which is here divided into six subsystems as population, resources, energy, economy, environment and ecosystem, with the planning horizon spanning from 2003 to 2020. Comparison between the original system dynamics (ORSD) model based on the existing economic structure of Beijing and the optimized system dynamics (OPSD) model adjusted according to the solutions of the multiple-objective programming (MOP) are conducted. The developing trend of each subsystem is simulated and illuminated, based on which constructive suggestions are provided for urban strategic planning of Beijing. The ISDMOP model is proved effective for investigating urban dynamics and realizing the multiple-objective programming.     

The Share-a-Ride Problem: People and parcels sharing taxis

New city logistics approaches are needed to ensure efficient urban mobility for both people and goods. Usually, these are handled independently in dedicated networks. This paper considers conceptual and mathematical models in which people and parcels are handled in an integrated way by the same taxi network. From a city perspective, this system has a potential to alleviate urban congestion and environmental pollution. From the perspective of a taxi company, new benefits from the parcel delivery service can be obtained. We propose two multi-commodity sharing models. The Share-a-Ride Problem (SARP) is discussed and defined in detail. A reduced problem based on the SARP is proposed: the Freight Insertion Problem (FIP) starts from a given route for handling people requests and inserts parcel requests into this route. We present MILP formulations and perform a numerical study of both static and dynamic scenarios. The obtained numerical results provide valuable insights into successfully implementing a taxi sharing service.     

灰色聚类法在城市公共交通发展水平评价中的应用

针对城市公共交通发展水平的评价难以做到客观、全面、准确的问题,构建了城市公共交通发展水平评价的指标体系及其递阶层次结构;运用灰色聚类分析法建立了数学模型对城市公共交通发展水平进行综合评价.利用该评价模型,对青岛市公共交通发展水平进行了实例分析,运行表明,评价结果与青岛市就公交现状所进行的民意调查结果基本吻合,提高了评价效率,从而提供了一条对城市公共交通发展水平进行定量分析的途径.     

Combining simulation and goal programming for healthcare planning in a medical assessment unit

This paper describes a detailed simulation model for healthcare planning in a medical assessment unit (MAU) of a general hospital belonging to the national health service (NHS), UK. The MAU is established to improve the quality of care given to acute medical patients on admission, and to provide the organisational means of rapid assessment and investigation in order to avoid unnecessary admissions. The simulation model enables different scenarios to be tested to eliminate bottlenecks in order to achieve optimal clinical workflow. The link between goal programming (GP) and simulation for efficient resource planning is explored. A GP model is developed for trade-off analysis of the results obtained from the simulation. The implications of MAU management preferences to various objectives are presented.     

基于结构洞理论的城市复杂项目群组织优化研究

研究目的:从城市复杂项目群组织的复杂性着手,针对目前项目群组织管理和控制在实际应用中出现的问题,研究一种优化项目群组织的有效方法.研究过程:基于结构洞理论模型,通过分析城市复杂项目群组织结构的网络特性,找到项目群组织中各个关系人之间的结构洞,以此作为研究的对象来建立组织的优化模型,在确立目标函数的情况下,通过结构约束算法求取网络规模的密度约束,并通过最小二乘法进行有效的修正.研究结论:通过模型的构建,可以得出结构洞理论是研究城市复杂项目群组织关系的有效理论方法,为其组织优化提供了交互视角,有利于组织中关系人目标的实现.     

中国城市土地利用效率的动态测度及影响因素——基于DEA-Tobit两步法的分析

利用数据包络模型(DEA)对中国大陆30个省、市、自治区2001—2010年城市土地利用效率进行了测度与评价,并运用Tobit回归模型对其影响因素进行了深入分析.结果表明:①中国城市土地利用效率总体呈现上升趋势,除少数省区效率值低于0.5以外,其余均保持在0.5-1之间;②城市土地利用效率前沿面分析结果显示,2001—2010年处于生产前沿面的省、市、自治区的数量保持稳定,但其空间分布却发生了一些变化,10年间东部地区减少2个,西部地区增加2个,中部地区一直处于零水平的状态;③城市土地利用过程中高投入低产出局面的扭转、非农从业人员效率的提高是城市土地利用效率改善的基本内核和关键所在;④经济规模对城市士地利用效率呈现正向促进作用,低层次的产业结构和不断增加的人口密度呈现负面影响,政府规制、空间集聚水平、城市规模和区位条件的影响并不显著.     

基于可拓模糊层次分析法的城市交通文化系统评价

为了科学地评价城市交通文化系统,并使评价方法更符合实际,对模糊层次分析法进行改进,提出了可拓模糊层次分析法,介绍了可拓模糊层次分析法的原理,给出了它的构成方法和具体评价模型,并用该评价模型对沈阳、大连、鞍山三个城市的交通文化系统进行了综合评价.结果表明,该方法较好地反映了实际交通文化系统的水平,克服了层次分析法中人的主观判断、选择、偏好对结果的影响,使评价结果更合理,是一种可信的多目标决策问题的评价方法,对城市交通文化系统评价是有效的.     

Fractal-based exponential distribution of urban density and self-affine fractal forms of cities

Urban population density always follows the exponential distribution and can be described with Clark’s model. Because of this, the spatial distribution of urban population used to be regarded as non-fractal pattern. However, Clark’s model differs from the exponential function in mathematics because that urban population is distributed on the fractal support of landform and land-use form. By using mathematical transform and empirical evidence, we argue that there are self-affine scaling relations and local power laws behind the exponential distribution of urban density. The scale parameter of Clark’s model indicating the characteristic radius of cities is not a real constant, but depends on the urban field we defined. So the exponential model suggests local fractal structure with two kinds of fractal parameters. The parameters can be used to characterize urban space filling, spatial correlation, self-affine properties, and self-organized evolution. The case study of the city of Hangzhou, China, is employed to verify the theoretical inference. Based on the empirical analysis, a three-ring model of cities is presented and a city is conceptually divided into three layers from core to periphery. The scaling region and non-scaling region appear alternately in the city. This model may be helpful for future urban studies and city planning.     

Improving emergency service in rural areas: a bi-objective covering location model for EMS systems

Emergency medical service (EMS) systems are public services that often provide the first line of response to urgent health care needs within a community. Unfortunately, it has been widely documented that large disparities in access to care exist between rural and urban communities. While rural EMS is provided through a variety of resources (e.g. air ambulances, volunteer corps, etc.), in this paper we focus on ground ambulatory care. In particular our goal is to balance the level of first-response ambulatory service provided to patients in urban and rural areas by locating ambulances at appropriate stations. In traditional covering location models the objective is to maximize demand that can be covered; consequently, these models favor locating ambulances in more densely populated areas, resulting in longer response times for patients in more rural areas. To address the issue of fairness in semi-rural/semi-urban communities, we propose three bi-objective covering location models that directly consider fairness via a secondary objective. Results are discussed and compared which provide a menu of alternatives to policy makers.     

基于AHP和DEA联用的城市交通环境可持续发展评价方法研究

将层次分析法(AHP)和数据包络分析(DEA)相结合构建了两种方法的联用评价模式,对使用该方法评价城市交通环境可持续发展水平和后续决策指导方面进行了探讨.该方法对AHP法在多个决策单元定量对比分析和DEA体现决策者偏好方面进行了改善.从影响城市交通环境可持续发展水平的城市综合发展、道路设施水平、交通运输功能和交通环境质量等方面出发,建立了城市交通环境可持续发展评价体系,并应用于深圳市实证分析,通过AHP分析认为深圳市2000～2007年城市交通环境可持续发展水平在波动中缓慢上升,再通过27个城市2005年数据DEA有效性分析和投影分析,得到深圳市在城市交通环境可持续发展方面的总体效率为0.9729,并得到了其要达到DEA有效的调整方案和部分政策建议.     

Effects of the urban environment on the trajectories of stack plumes

A numerical model for plume rise is used, together with a model of the urban mixing layer, to study the effects of the inhomogeneous temperature structure of the city of Leeds on the trajectory of effluent plumes. Consideration is given to chimney location, source strength, city topography, areal sources, wind speed and rural ground level temperatures.     

Making Organizational Learning Operational: Implications from Learning Classifier Systems

The concepts of organizational learning in organization and management science cover a very wide range of organization-related activities in organization. Since socially situated intelligence is one of such activities, this paper makes the concept of organizational learning operational from the computational viewpoint for investigating socially situated intelligence. In particular, this paper focuses on the characteristics of multiagent learning as one kind of socially situated intelligence, and analyzes them using four operationalized learning mechanisms in organizational learning. A careful investigation on the characteristics of multiagent learning has revealed the following implications: (1) there are two levels in the learning mechanisms for multiagent learning (the individual level and organizational level) and each mechanism is divided into two types (single- and double-loop learning). The integration of these four learning mechanisms improves socially situated intelligence; and (2) the following properties support socially situated intelligence: (a) different dimensions in learning mechanisms, (b) interaction among various levels and types of learning mechanisms in addition to interaction among agents, and (c) combination of exploration at an individual level and exploitation at an organizational level.     

INDUSTRIAL WASTEWATER CONTROL IN CHINESE CITIES: DETERMINANTS OF SUCCESS IN ENVIRONMENTAL POLICY

The research reported in this paper has three objectives: (1) to examine trends in Chinese industrial wastewater pollution and to describe policies developed to control this pollution; (2) to analyze relationships between the degree of industrial wastewater pollution control and the economic, demographic, and organizational characteristics of major Chinese cities; and (3) to identify factors that determine the success of the government's efforts to control industrial wastewater pollution. The study specifies and econometrically estimates a system of pollution control equations based on a unique data set for 82 Chinese cities from 1985 to 1990. Results demonstrate that the structure of enterprise ownership and investment in environmental management capacity are associated with increases in the effectiveness of wastewater pollution control. The Discharge Permit System, one of China's main strategies for urban environmental protection, appears to have been moderately successful in increasing wastewater treatment, but it has not encouraged enterprise managers to adopt less-polluting production technology.     

长沙建设国家中心城市的对策研究

建设国家中心城市是长沙市近年的奋斗目标.长沙市怎样建设国家中心城市,可以从与国内其他国家中心城市的全面比照当中得到建设方案.一是从经济实力、产业结构、科教实力、金融行业发展、对外开放等代表城市综合实力的5个方面,二是从引领和辐射功能、集聚功能、物流枢纽功能等代表城市功能的3个方面,对长沙与国内5个国家中心城市(天津、重庆、成都、武汉、郑州)进行对比研究.通过对比,从国内5个国家中心城市的城市功能差别当中找准长沙的城市功能定位,从长沙市城市综合实力的差距和优劣势当中发现长沙建设国家中心城市所要解决的问题,为此提出长沙建设国家中心城市的建设对策.