Emergy-based analysis of Beijing–Tianjin–Tangshan region in China

An emergy-based analysis was conducted for the Beijing–Tianjin–Tangshan urban agglomeration district from perspectives of emergy density, resource structure, environmental pressure and resource use efficiency during the period of 1991–2005. The results showed that Beijing, Tianjin and Tangshan as contiguous regions shared similar characters and evolving trends in certain aspects as emergy intensity and proportion of local renewable resources on the whole. As for the local resources availability, process efficiency and environmental pressure, however, these three cities have significant differences. With comparison of the other cities in China, it is shown that Beijing–Tianjin–Tangshan region has higher environment loading and lower sustainability level though enjoying rapid urbanization process and economic development. This study also suggests that the first priority on economic development competition within urban agglomeration regions may lead to the wasting of resources and redundant construction, while cooperative and rational selection for development pattern are the proper choice for coordinate regional development and long term sustainability to overcome resource restrictions.     

Measurement and evaluation of the metabolic capacity of an urban ecosystem

Cities as superorganisms confront disturbances from their metabolic processes, including large metabolic fluxes, low stocks of resources and products, and a low efficiency of the urban material metabolism. Based on ecological thermodynamics, an indicator system is established in this paper to evaluate the fluxes, stocks, and effiency of the urban material metabolism using emergy analysis. Also, a new model for the urban material metabolism is proposed to define the production possibility curve using a wealth index (WI) and an ecological effiency index (EEI). Then, six large Chinese cities including Beijing, Shanghai, Tianjin, Chongqing, Guangzhou, and Shenzhen are selected as typical cases to validate the proposed model. The results show that Shenzhen has the highest metabolic capacity, followed by Beijing, Shanghai, Guangzhou, Tianjin, and Chongqing. It is also reflected that different urban material metabolisms of the six cities are resulted from the varied regional metabolic capacities, thus providing insights into how cities improve their metabolic capacities. Meanwhile, Shenzhen has the highest WI and EEI, Chongqing has the lowest WI and EEI, and Beijing, Shanghai, Tianjin, and Guangzhou has low WI and high EEI. It is also shown that the sustainable operation of the urban material metabolism reflects the mutualism and symbiosis between socioeconomic development and ecological environment protection.     

Emergy as embodied energy based assessment for local sustainability of a constructed wetland in Beijing

Ecological treatment engineering has been widely accepted as an artificially designed work to deal with the deteriorating ecological environment with low energy and resource consumption. To measure the energy and resource consumption and environmental support contained in the constructed wetland as a kind of ecological treatment engineering, emergy as embodied solar energy based assessment is performed and relative emergy-based indices including emergy yield ratio (EYR), emergy load ratio (ELR), emergy sustainability index (ESI), net economic benefit index (Np), and renewable percentage index (Pr), are also modified to evaluate the local sustainability of the constructed wetland in this paper. A case study on Longdao River constructed wetland compared with those of some earlier conventional treatment systems indicate that more local renewable resources and less ecological cost are involved, thus promoting the economic benefit due to less energy and resource consumption and simultaneously lowering the environmental stress of the treatment system on the local areas.     

Ecological evaluation of Beijing economy based on emergy indices

An integrated ecological evaluation of the Beijing economy was presented in the paper based on the emergy accounting with the data in 2004. Through calculating environmental and economic inputs within and outside the Beijing economy, this paper discusses the Beijing’s resource structure, economic situation and trade status based on a series of emergy indicators. Through the comparison of the systematic indicators of Beijing with those of the selected Chinese cities, the general status of the Beijing economy in China is identified. The results also show that most indicators of Beijing are located at middle levels among the selected Chinese cities. Particularly, the environmental impacts, expressed by the ratio of waste to the renewable emergy, and the ratio of waste to the total emergy use, are 84.2 and 0.26, respectively in Beijing in 2004, which indicate that the Beijing economy is greatly reliant on the imported intensive fuels, goods and services with high empower density and environmental loading.     

Emergy analysis of a farm biogas project in China: A biophysical perspective of agricultural ecological engineering

This paper aims to present a biophysical understanding of the agricultural ecological engineering by emergy analysis for a farm biogas project in China as a representative case. Accounting for the resource inputs into and accumulation within the project, as well as the outputs to the social system, emergy analysis provides an empirical study in the biophysical dimension of the agricultural ecological engineering. Economic benefits and ecological economic benefits of the farm biogas project indicated by market value and emergy monetary value are discussed, respectively. Relative emergy-based indices such as renewability (R%), emergy yield ratio (EYR), environmental load ratio (ELR) and environmental sustainability index (ESI) are calculated to evaluate the environmental load and local sustainability of the concerned biogas project. The results show that the farm biogas project has more reliance on the local renewable resources input, less environmental pressure and higher sustainability compared with other typical agricultural systems. In addition, holistic evaluation and its policy implications for better operation and management of the biogas project are presented.     

Optimizing project selection: a perspective from resource constraints

In reality, projects usually consume complex resources. Making good use of the various resources is vital for optimal project selection and maximum profit earning. This paper proposes a new project selection model from the perspective of complex resource constraints. In the model, the resources are divided into non-renewable and renewable categories, and some resources of the two categories can both be shared by different projects. In addition, the paper considers the situation where the company has resources in stock and can purchase them in the marketplace if they are out of stock. The paper proves that the proposed model which considers renewable resource and resource sharing produces higher profit than the ones that do not consider renewable resource and resource sharing. To solve the complex model problem, an improved genetic algorithm is presented. For the sake of illustration, a case study is provided.     

Emergy analysis for ‘Four in One’ peach production system in Beijing

‘Four in One’ production system has been widely used for recent years in rural areas of Beijing. The aim of this study is to assess the efficiency and sustainability of the ‘Four in One’ ecological economic system for peach production system (FIOPPS) in the solar greenhouse in Pinggu district, Beijing, by emergy-based ecological analysis. The emergy-based indicators of the FIOPPS are calculated and compared with those of the conventional solar greenhouse peach production system. By comparison, the FIOPPS is proved to be more sustainable with less pressure on the environment, better economic benefit and higher efficiency of agricultural resource utilization, thus worthy of being generalized to boost the ecological agriculture in the rural areas of China.     

Emergy-based urban ecosystem health assessment: A case study of Baotou,China

Ecosystem health has been a hot topic of ecosystem management research for years. Considering the urban area as a complex ecosystem consisted of natural, societal and economic entities, urban ecosystem health assessment is necessary to be conducted for the scientific management and proper ecological restoration. Combining with the ecosystem service function of the urban ecosystem, theoretical framework and methodology of the urban ecosystem health assessment based on emergy are proposed and the temporal variation of the health level of the city are also outlined in this paper. Following the principle of ecosystem health assessment, four major factors, including vigor (V), organizational structure (O), resilience (R) and function maintenance (F), are integrated to construct a novel emergy-based urban ecosystem health index (EUEHI). Based on the EUEHI and comparing with those of five other typical Chinese cities, the case study of Baotou city shows that its urban ecosystem health level is steadily arising despite the year 2001 as a turning point. Due to the emphasis on the resource structure adjustment and utilization efficiency, Baotou has obtained a better organizational structure and service function for the total urban ecosystem.     

A scatter search algorithm for project scheduling under partially renewable resources

In this paper we develop a heuristic algorithm, based on Scatter Search, for project scheduling problems under partially renewable resources. This new type of resource can be viewed as a generalization of renewable and non-renewable resources, and is very helpful in modelling conditions that do no fit into classical models, but which appear in real timetabling and labor scheduling problems. The Scatter Search algorithm is tested on existing test instances and obtains the best results known so far.     

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.     

Resource Constrained Scheduling within Fixed Project Durations

This paper presents a practical approach for resource constrained scheduling within a given project duration. The method ensures a stable project plan when activity durations are reduced to achieve this. It handles all four categories of resource (unconstrained, renewable, non-renewable and doubly-constrained resources), and aims to shorten the project duration at minimum cost. Soft constraints and resource availabilities which vary over time are allowed in the method. Computational experience is reported.     

The multi-mode resource-constrained project scheduling problem with generalized precedence relations

In this paper, we tackle the challenging problem of scheduling activities to minimize the project duration, in which the activities (a) are subject to generalized precedence relations, (b) require units of multiple renewable, non-renewable and doubly constrained resources for which a limited availability is imposed, and (c) can be performed in one of several different ways, reflected in multiple activity scenarios or modes. These multiple modes give rise to several kinds of trade-offs (time/resource, time/cost and resource/resource trade-offs) which allow for a more efficient allocation and use of resources. We present a local search-based solution methodology which is able to handle many real-life project scheduling characteristics such as time-varying resource requirements and availabilities, activity ready times, due dates and deadlines, activity overlaps, activity start time constraints and other types of temporal constraints.     

Resources use and greenhouse gas emissions in urban economy: Ecological input–output modeling for Beijing 2002

The embodiment of natural resources and greenhouse gas emissions for the urban economy of Beijing economy 2002 by a physical balance modeling is carried out based on an extension of the economic input–output table into an ecological one integrating the economy with its various environmental driving forces. Included resources and greenhouse gas emissions belong to six categories as energy resources in terms of primary energy and secondary energy; water resource; emissions of CO₂, CH₄, and N₂O; exergy in terms of energy sources, biological resources and minerals; and solar emergy and cosmic emergy in terms of climate resources, soil, energy sources, and minerals.     

Cosmic emergy based ecological systems modelling

Ecological systems modelling based on the unified biophysical measure of cosmic emergy in terms of embodied cosmic exergy is illustrated in this paper with ecological accounting, simulation and scenario analysis, by a case study for the regional socio-economic ecosystem associated with the municipality of Beijing. An urbanized regional ecosystem model with eight subsystems of natural support, agriculture, urban production, population, finance, land area, potential environmental impact, and culture is representatively presented in exergy circuit language with 12 state variables governing by corresponding ecodynamic equations, and 60 flows and auxiliary variables. To characterize the regional socio-economy as an ecosystem, a series of ecological indicators based on cosmic emergy are devised. For a systematic ecological account, cosmic exergy transformities are provided for various dimensions including climate flows, natural resources, industrial products, cultural products, population with educational hierarchy, and environmental emissions. For the urban ecosystem of Beijing in the period from 1990 to 2005, ecological accounting is carried out and characterized in full details. Taking 2000 as the starting point, systems modelling is realized to predict the urban evolution in a one hundred time horizon. For systems regulation, scenario analyses with essential policy-making implications are made to illustrate the long term systems effects of the expected water diversion and rise in energy price.     

Transitional dynamics in an R&D-based growth model with natural resources

In this paper, we prove the existence and uniqueness of the optimal path for a resource endowed economy with R&D. This path converges to an optimal steady state, which is a saddle point, for each type of resources (renewable or non-renewable). In this steady state, a finite size resource sector coexists with other continuously growing sectors. In comparison, the corresponding decentralized equilibrium is suboptimal and there is either over- or under-investment in R&D from the social planner’s perspective. At optimum, positive long-run growth will be sustained regardless type of resources used.     

GRASP and path relinking for project scheduling under partially renewable resources

Recently, in the field of project scheduling problems the concept of partially renewable resources has been introduced. Theoretically, it is a generalization of both renewable and non-renewable resources. From an applied point of view, partially renewable resources allow us to model a large variety of situations that do not fit into classical models, but can be found in real problems in timetabling and labor scheduling. In this paper, we develop some preprocessing techniques and several heuristic algorithms for the problem. Preprocessing significantly reduces the dimension of the problems, therefore improving the efficiency of solution procedures. Heuristic algorithms based on GRASP and Path relinking are then developed and tested on existing test instances, obtaining excellent results.     

核心城市房地产市场的联动和溢出特征研究——基于中国“北上广深”样本的经验考察

本文基于房价长期趋势和短期波动层面,基于HP滤波法分离北京、上海、广州和深圳四大一线城市的房价,采用有向无环图和信息溢出指数方法剖析了核心城市房价之间的同期联动效应和信息溢出效应,并结合滚动窗口估计法分析了信息溢出对外部信息和调控政策的反应程度。结果显示:一线城市房价之间有紧密的联系程度和较高的信息溢出规模。在同期联动效应上,深圳房价趋势的对外联动效应最明显,北京房价趋势在同期最易受其它城市影响;上海房价波动存在较强的对外联动效应,深圳房价波动受其它一线城市的波动冲击较迅速。在信息溢出效应上,深圳房价趋势有引领作用,对外溢出效应最强;上海房价波动处于引导地位,中长期对其它市场影响最大。核心城市房价趋势之间的溢出指数随着利好政策信息的出现而上升,随着限制政策等不利信息的出现而下降。核心城市房价波动之间的溢出效应对于外部信息反应更为灵敏,国家对房地产市场的调控政策增大核心城市房价波动的信息溢出规模。     

Emergy evaluations for constructed wetland and conventional wastewater treatments

Based on emergy synthesis, this study presents a comparative study on constructed wetland (CW) and conventional wastewater treatments with three representative cases in Beijing. Accounting the environmental and economic inputs and treated wastewater output based on emergy, different characteristics of two kinds of wastewater treatments are revealed. The results show that CWs are environment-benign, less energy-intensive despite the relatively low ecological waste removal efficiency (EWRE), and less cost in construction, operation and maintenance compared with the conventional wastewater treatment plants. In addition, manifested by the emergy analysis, the cyclic activated sludge system (CASS) has the merit of higher ecological waste elimination efficiency.     

Two Approaches to Problems of Resource Allocation Among Project Activities — A Comparative Study

The paper deals with a class of problems of resource allocation among project activities, where the resource requirements of each activity concern numbers of resource units from given finite sets for particular resource types. Three categories of constrained resources are considered in a general model: renewable (only total usage at every moment is constrained), non-renewable (only total consumption over the period of project duration is constrained) and doubly-constrained (both usage and consumption are constrained). For every feasible combination of resource amounts, the performing time of each activity is known. Time and cost criteria are considered for project performance evaluation. For solving these problems, two general approaches using linear programming in specific ways are described. These approaches are different in nature, the difference being reflected in the range of problems solved by them and in their computational properties. This is shown by an extensive comparison of both approaches. This comparison also characterizes the state-of-the-art across the problems and points out desirable directions for further research.     

Sustainability screw: role of relative production and abatement time scales

We postulate that reasonable notions of sustainability must include a time-scale synchronization of both the processes of human development and those of the natural environment. We perform our analysis within a simple system of five differential equations where non-renewable and renewable resources are coupled with production capacities, abatement and human capital as functions of time. A ‘sustainability screw’ phenomenon is demonstrated describing a spiral like trajectory of three key variables—the non-renewable resources, the renewable resources and the production capital. This spiral may tend to an undesirable steady state, however, by adjusting a ratio of intensity parameters, time scales of production and natural recovery processes can be altered to produce more sustainable trajectories.