Empirica - Previous studies that have investigated the J-curve phenomenon between the UK and its largest trading partner from the European Union (EU), Germany, used aggregate bilateral trade data... 相似文献
This study examines the recent quantitative characteristics of dry season water allocation in the Chao Phraya River basin, Thailand. Previous studies have focused on inequitable allocation, where the highest priority is given to the domestic water sector and uneven irrigation water variability exists among projects in the delta. This study uses a statistical test and panel data analysis to confirm that the characteristics highlighted in previous studies remain accurate, and it discusses the source of these characteristics in order to understand the issues in water allocation in the Chao Phraya River delta. 相似文献
Artificial neural networks (ANN) are applicable for and forecasting without the need to calculate complex nonlinear functions. This paper evaluates the effectiveness of temperature, evapotranspiration, precipitation and inflow factors, and the lag time of those factors, as variables for simulating and forecasting of runoff. The genetic algorithm (GA) is coupled with ANN to determine the optimal set of variables for streamflow forecasting. The minimization of the total mean square error (MSE) is considered as the objective function of the ANN-GA method in this paper. Our results show the effectiveness of the ANN-GA for simulating and forecasting runoff with consistent accuracy compared with using pure ANN for runoff simulation and forecasting. 相似文献
Over the last decade, evolutionary and meta-heuristic algorithms have been extensively used as search and optimization tools in various problem domains, including science, commerce, and engineering. Their broad applicability, ease of use, and global perspective may be considered as the primary reason for their success. The honey-bees mating process may also be considered as a typical swarm-based approach to optimization, in which the search algorithm is inspired by the process of real honey-bees mating. In this paper, the honey-bees mating optimization algorithm (HBMO) is presented and tested with few benchmark examples consisting of highly non-linear constrained and/or unconstrained real-valued mathematical models. The performance of the algorithm is quite comparable with the results of the well-developed genetic algorithm. The HBMO algorithm is also applied to the operation of a single reservoir with 60 periods with the objective of minimizing the total square deviation from target demands. Results obtained are promising and compare well with the results of other well-known heuristic approaches. 相似文献
Water scarcity is one of the problems affecting people’s livelihoods in arid and semi-arid areas, requiring a sustainable balance between water demands and water resources. This study was carried out to assess temporal and spatial distribution of water supply and demand in order to help managers to overcome water scarcity in Jiroft basin, southeastern Iran. Spatial supply and demand of water were mapped and standardized rainfall index (SPI) was used to assess drought for a 20 years period (1994–2014). Supply and demand of water were matched in 23% of the basin area, mostly concentrated in the cold zones. Water supply was reduced up to 80% during dry years, declining water supply-demand matching to 5% of the basin area. Shrub-grass rangelands and deciduous woodlands were the most valuable land covers for conservation with $ 1,100 and $ 936 per hectare water prices respectively. Water value dropped more than 72% in mismanaged ecosystems (p?<?0.01). Our finding showed that water supply-demand ratio can be used as a proxy of ecosystem health and water-yield, which can provide a good information for water resources managers to reduce the threats of water scarcity in arid and semi-arid regions.
Water Resources Management - Change in the spatiotemporal pattern of precipitation is one the most important effects of climate change. This may result in considerable changes in urban flooding and... 相似文献
This note commemorates and celebrates the life and contribution of M. Hadi Soesastro, a Bulletin board member who passed away on 4 May 2010. Hadi was arguably Indonesia's leading public intellectual in the fields of international economic policy and political economy, ASEAN economic cooperation, and East Asian economic integration. He made seminal contributions in these fields, and on the political economy of reform in Indonesia, the economic development of East Timor, and energy economics. He also played a major role in institutional development, most notably at the Centre for Strategic and International Studies, and in many other official, academic and research endeavours in Indonesia and East Asia. 相似文献
Reservoir operation rules are intended to help an operator so that water releases and storage capacities are in the best interests
of the system objectives. In multi-reservoir systems, a large number of feasible operation policies may exist. System engineering
and optimization techniques can assist in identifying the most desirable of those feasible operation policies. This paper
presents and tests a set of operation rules for a multi-reservoir system, employing a multi-swarm version of particle swarm
optimization (MSPSO) in connection with the well-known HEC-ResPRM simulation model in a parameterization–simulation–optimization
(parameterization SO) approach. To improve the performance of the standard particle swarm optimization algorithm, this paper
incorporates a new strategic mechanism called multi-swarm into the algorithm. Parameters of the rule are estimated by employing a parameterization–simulation–optimization approach,
in which a full-scale simulation model evaluates the objective function value for each trial set of parameter values proposed
with an efficient version of the particle swarm optimization algorithm. The usefulness of the MSPSO in developing reservoir
operation policies is examined by using the existing three-reservoir system of Mica, Libby, and Grand Coulee as part of the
Columbia River Basin development. Results of the rule-based reservoir operation are compared with those of HEC-ResPRM. It
is shown that the real-time operation of the three reservoir system with the proposed approach may significantly outperform
the common implicit stochastic optimization approach. 相似文献
A numerical procedure is presented for the optimization of the position of water quality monitoring stations in a pressurized water distribution system (WDS). The procedure is based on the choice of the set of sampling stations which maximizes the monitored volume of water while keeping the number of stations at minimum. The optimization model is formulated in terms of integer programming, and the solution of the mathematical problem is efficiently approximated by means of a multi-objective multi-colony ant algorithm. A built-in routine is developed for calculation of the water fraction matrix and integrated into the general modeling structure to facilitate data entry and storage to minimize problems associated with water fraction matrix determination for varying scenarios and coverage criteria for any scenario. The proposed methodology is very robust in analyzing the effects of different scenarios and/or number of potential monitoring stations by eliminating the need of employing an off-line routine for coverage matrix identification. Robustness, ease of generalization, multi-objective nature, and computational efficiency are the main characteristics and novelty of the proposed approach. Monitoring stations are optimally located in a large-scale real-world network with 104 nodes and multiple demands using the proposed ACO models. The set of non-dominated solutions forming the Pareto front for a number of monitoring stations and the total coverage of the system are also presented. 相似文献
On demand use of direct precipitation of wastewater has been successfully implemented at several large Scandinavian wastewater treatment plants (WWTPs) as a cost-efficient method of treating wastewater bypassing secondary treatment. During wet weather situations or when the capacity of secondary treatment is reduced excess wastewater can be treated through efficient direct precipitation. This increases the total capacity of the WWTP to remove phosphorus during these periods. This treatment strategy allows the WWTPs to meet stringent effluent phosphorus limits without extending secondary treatment of the main plant, despite high wet weather flows. The gain in terms of reduced phosphorus emissions varies depending on local conditions such as climate, collection system and secondary treatment capacity. It also varies from year to year depending on the weather and reductions of capacity due to planned refurbishing or unplanned breakdown of equipment. Operating chemical precipitation on demand has proved to contain challenges to operation and organisation of the WWTP. These challenges include logistics of start-up, training of staff and maintaining the system between occasions of operation. Sufficient up-stream storage capacity, reliable weather forecasts and good contracts with suppliers of chemicals are keys of success. 相似文献