In order to maintain the overall social interest in land use and improve the level of land administration, an information system for land-use planning and management （ISLUPM） was established, which is composed of pr...In order to maintain the overall social interest in land use and improve the level of land administration, an information system for land-use planning and management （ISLUPM） was established, which is composed of presentation layer, business logic layer and data layer in the general structure. The application support platform of the ISLUPM, built based on COM, COM ＋ and .NET standard components, includes data engine, data management, assemblies, components management, operation management, and interface. Then, an elaboration was made on major functions of the ISLUPM, such as planning revision scheme, planning operation flow, digital processing, thematic analysis and inquiry, and preparation of the chart of reserved land resources. The developed system has been successfully applied to the land-use planning and management work of Longquanyi District, Chengdu, China. It may provide a reference for development of geographic information system （GIS） for land and resources.展开更多
Management Information System provides an effective way for enterprises to improve their competitive abilities. It presents a framework for improving the management models through the design and implementation of effe...Management Information System provides an effective way for enterprises to improve their competitive abilities. It presents a framework for improving the management models through the design and implementation of effective and high-quality MIS. So it is very important to the modem management of corporations. ERP （Enterprise Resource Planning） system is one of the core parts of MIS, which solves the matter of management model mainly. ERP is a popular method enabling the business processes required to compete with the globalization. The thesis cites SAP R/3 to introduce the general structure and function of ERP. Global Enterprise Resource Planning Implementation is increasingly becoming the successful choice of MIS.展开更多
The developmental activities, particularly the construction of hydroelectric projects are causing a great loss of biodiversity in the Indian Himalayan Region. The Himaehal Pradesh, a part of IHR is well known for the ...The developmental activities, particularly the construction of hydroelectric projects are causing a great loss of biodiversity in the Indian Himalayan Region. The Himaehal Pradesh, a part of IHR is well known for the development of hydroelectric projects. The Parbati H.E. Project is amongst the major projects of the State. The different stages of the project are all causing loss of biodiversity of the area. Stage Ⅲ of the Parbati H.E. Project is a run of the river scheme on the Sainj River downstream of Power House of Parbati H.E. Project Stage Ⅱ. The project shall utilize regulated discharge of Parbati H.E. Project Stage Ⅱ and inflow of River Sainj for power generation, and has been contemplated as a peaking station operating in tandem with Stage Ⅱ. The present study has been undertaken to see the impact of hydroelectric project on the biodiversity, particularly on medicinal plants. A total of 104 species of medicinal plants, belonging to different life forms, i.e., trees （23 spp.）, shrubs （22 spp.）, herbs （57 spp.） and ferns （2 spp.） were recorded. The species have been analyzed and studied for their distribution, classification, altitudinal zones, part （s） used, indigenous uses, nativity, endemism and rarity.Different parts of these species, such as whole plants, roots （including rhizomes and tubers）, leaves, flowers, fruits, seeds, stems, barks, spikes, nuts and insect galls are used by the inhabitants for curing various diseases and ailments. 3o species are native to the Himalayan region, 9 species native to the Himalayan region and adjacent countries also and 65 species are non-natives. 9 species are near endemics. Considering the whole Himalaya as a biogeographie unit （sensu lato）, the near endemics are endemic to the Himalaya. Among these species, Zanthoxylum armature is categorized as Endangered and Valeriana wallichii as Vulnerable. Hedychium spicatum, Rhus javanica, Berberis lycium, Thalictrum foliolossum, Salvia lanata, Rubia cordifolia and Bergenia ligulata may be considered as threatened species due to their over exploitation for trade. 90 species are propagated by seeds, 8 species by seeds and rhizomes/roots/tubers, 4 species by seeds and cuttings, and 2 species by sori. A management plan for the cultivation and conservation of the medicinal plants in the dam submergence area, and the commercially viable medicinal plants with high value in the catchment area is suggested.展开更多
Simulation is a powerful tool for improving,evaluating and analyzing the performance of new and existing systems.Traffic simulators provide tools for studying transportation systems in smart cities as they describe th...Simulation is a powerful tool for improving,evaluating and analyzing the performance of new and existing systems.Traffic simulators provide tools for studying transportation systems in smart cities as they describe the evolution of traffic to the highest level of detail.There are many types of traffic simulators that allow simulating traffic in modern cities.The most popular traffic simulation approach is the microscopic traffic simulation because of its ability to model traffic in a realistic manner.In many cities of Saudi Arabia,traffic management represents a major challenge as a result of expansion in traffic demands and increasing number of incidents.Unfortunately,employing simulation to provide effective traffic management for local scenarios in Saudi Arabia is limited to a number of commercial products in both public and private sectors.Commercial simulators are usually expensive,closed source and inflexible as they allow limited functionalities.In this project,we developed a local traffic simulator“KSUtraffic”for traffic modeling,planning and analysis with respect to different traffic control strategies and considerations.We modeled information specified by GIS and real traffic data.Furthermore,we designed experiments that manipulate simulation parameters and the underlying area.KSUTraffic visualizes traffic and provides statistical results on the simulated traffic which would help to improve traffic management and efficiency.展开更多
Catchment floods are more challenging due to intensive urbanization and climate change.Enlightened by the Low Impact Development(LID),China initiated the Sponge City Program(SCP)to transform Urban Flood Management(UFM...Catchment floods are more challenging due to intensive urbanization and climate change.Enlightened by the Low Impact Development(LID),China initiated the Sponge City Program(SCP)to transform Urban Flood Management(UFM)to be more environmentally friendly in 2013.The China National Government(CNG)has subsidized municipal SCP facilities to enhance urban flood resilience while delivering multiple co‐benefits for urban ecosystems and social well‐being.Recent floods at Schleiden(Germany),Arizona State(USA),and Zhengzhou(China)in 2021 reflected the necessity of Catchment Flood Management(CFM)to cover the whole catchment scale.The SCP,designed to handle small‐scale urban pluvial floods,has brought concerns when facing larger‐scale fluvial floods after the Zhengzhou 2021 flood.Indeed,catchment‐scale Natural Flood Management(NFM)can manage fluvial floods while improving flood adaptations sustainably from upstream to downstream reaches.This research develops a new framework named the Sponge Catchment Management Plan(SCMP),including structural and Nonstructural elements.On the structural side,the SCMP framework integrates NFM with the SCP and Grey Engineering(GE)for reducing the fluvial flood discharge peaks in the whole‐catchment scale.On the nonstructural side,the SCMP encourages collaborative governance,revising technical standards,and improving“bottom‐up”participation.This research used Semi‐Structured Interviews(SSIs)and a Focus Group Approach(FGA)to explore 62 professional and Nonprofessional stakeholders’perspectives on the SCMP framework.Some professional respondents did not know much about the NFM and were worried about the effectiveness of this practice.But most interviewees supported the SCMP pilot work and shared the co‐benefits from the NFM.This case study at the SW China,Guiyang,could be a lesson to encourage other Chinese cities further implement SCP to improve catchment‐scale flood resilience.展开更多
Objective To study the origin and development,framework and content of the EU-RMP(European Drug Risk Management Plan)so as to provide a reference for China’s drug risk management plan(RMP).Methods Literature research...Objective To study the origin and development,framework and content of the EU-RMP(European Drug Risk Management Plan)so as to provide a reference for China’s drug risk management plan(RMP).Methods Literature research and comparative research were used in this paper.Through searching Chinese and foreign literature,the website of European Medicines Agency(EMA)and the Guideline on Good Pharmacovigilance Practices(GVP),in-depth understanding of the EU-RMP content and requirements,some lessons were extracted for our reference.Results and Conclusion All departments should cooperate closely in the preparation of RMP in China.Then,the risk control measures should be further enriched to reduce the risks.Besides,the rules for implementing RMP should be clarified to promote the risk management of the whole life cycle of drugs and maintain the safety of patients’medication.展开更多
The General Office of the State Council released the 13th Five-Year Plan for China's National Emergency System Construction(Plan for short).According to the Plan,China's emergency management laws and regulatio...The General Office of the State Council released the 13th Five-Year Plan for China's National Emergency System Construction(Plan for short).According to the Plan,China's emergency management laws and regulations and standards system need to be further improved and the basic capabilities of emergency management should continue to be enhanced.展开更多
The necessity to recognize the subsurface or underground and all its current and potential uses as part of our urban environment,to integrate this into urban planning and governance,and to foster conscious allocation ...The necessity to recognize the subsurface or underground and all its current and potential uses as part of our urban environment,to integrate this into urban planning and governance,and to foster conscious allocation of subsurface space has been increasingly recognized over the last century.At the same time,systems thinking as a‘buzz-word’has gained relevance for approaching complex problem areas in all kinds of disciplines including those preoccupied with the subsurface.This paper reviews the literature about urban underground planning through a systems-lens.To set this in context,it is outlined how organizational principles for the urban subsurface have evolved,and the main aspects of systems thinking are introduced followed by a discussion of how this thinking could be applied to the urban underground.Strategies and tools presented in the recent literature in the field are then reviewed based on this perspective,asking how systemic the proposed strategies and tools are when the local geology,as well as legal and institutional settings are accepted as a baseline for analysis or intervention.Systemic approaches built on this premise have the potential to capture existing and evolving complexities,foster a better understanding of the value of subsurface space for a city and ultimately enable an efficient and fair allocation of underground space.However,propositions for holistic solutions remain dispersed,interventions often remain based in an engineering mindset,and a shift in mind-set remains a challenge.More research in collaboration with local and regional administrations or authorities based on systems thinking frameworks could help to facilitate this shift.展开更多
This paper introduces the energy consumption status in China, elaborate the affects of the unreasonable energy consumption structure on energy environment and sustainable development of economy. Simultaneously, it poi...This paper introduces the energy consumption status in China, elaborate the affects of the unreasonable energy consumption structure on energy environment and sustainable development of economy. Simultaneously, it points out the solution, i.e., to implement integrated resources planning (IRP)/demand side management (DSM), and gives some recommendations on the way of implementing IRP/DSM.展开更多
Exercise training provides physiological benefits for both improving athletic performance and maintaining good health. Different exercise training modalities and strategies exist. Two common exercise strategies are hi...Exercise training provides physiological benefits for both improving athletic performance and maintaining good health. Different exercise training modalities and strategies exist. Two common exercise strategies are high-intensity interval training （HIIT） and moderate-intensity continuous exercise training （MCT）. HIIT was first used early in the 20th century and popularized later that century for improving performance of Olympic athletes. The primary premise underlying HIIT is that, compared to energy expenditure-matched MCT, a greater amount of work is performed at a higher intensity during a single exercise session which is achieved by alternating high-intensity exercise intervals with low-intensity exercise or rest intervals. Emerging research suggests that this same training method can provide beneficial effects for patients with a chronic disease and should be included in the comprehensive medical management plan. Accordingly, a major consideration in developing an individual exercise prescription for a patient with a chronic disease is the selection of an appropriate exercise strategy. In order to maximize exercise training benefits, this strategy should be tailored to the individual＇s need. The focus of this paper is to provide a brief summary of the current literature re^ardin~ the use of HIIT to enhance the fimctional capacity of individuals with cardiovascular, pulmonary, and diabetes diseases.展开更多
A GIS is proposed as a tool for the managing plan for the Antarctic specially managed area (ASMA) in Admiralty Bay.The ASMA comprises the area considered to be within the glacial drainage basin of the bay.Furthermore,...A GIS is proposed as a tool for the managing plan for the Antarctic specially managed area (ASMA) in Admiralty Bay.The ASMA comprises the area considered to be within the glacial drainage basin of the bay.Furthermore,it includes part of SSSI No.8 adjacent to the area but outside of the glacial drainage basin.Three stations and six refuges are located in the area.Using a SPOT satellite image map,the limits of the ASMA are marked and its area is re_calculated.It consists of 362 km 2,including 186 km 2 island ice field and small cirque glaciers and 32 km 2 ice_free field.The rest comprises water of the bay and a small adjacent area (8 km 2) of the Bransfield Strait.The ASMA_GIS will consists of 12 data layers ranging from the physiographic settings to the biological and administrative features.All data will be implemented into Arc/Info GIS according to the cartographic guidelines of the SCAR WG_GGI.First,five plans of information will be realised using a topographic database compiled from various sources and data from the revised bathymetric chart published by the Brazilian Navy Hydrographic Survey and also including: 1) Limits of the ASMA and protected areas;2) Glaciological features (e.g.drainage basin limits) and 3) Human presence (e.g.stations and historical sites).These basic GIS layers will be operational in early 2001.Then,additional data on the remaining layers (e.g.hydrology,geology and geomorphology) will be included from published sources. The ASMA_GIS will form an important database for environmental monitoring and studies surveying temporal changes of features such as glacier front positions or bird breading sites.展开更多
This paper examines task partition problem in a Multiagent based Distributed Open Computing Environment Model(MDOCEM). We first present a formal method to describe the task partition problem, then give a heuristic al...This paper examines task partition problem in a Multiagent based Distributed Open Computing Environment Model(MDOCEM). We first present a formal method to describe the task partition problem, then give a heuristic algorithm to solve the task partition problem that gives an approximate optimum solution.展开更多
文摘In order to maintain the overall social interest in land use and improve the level of land administration, an information system for land-use planning and management （ISLUPM） was established, which is composed of presentation layer, business logic layer and data layer in the general structure. The application support platform of the ISLUPM, built based on COM, COM ＋ and .NET standard components, includes data engine, data management, assemblies, components management, operation management, and interface. Then, an elaboration was made on major functions of the ISLUPM, such as planning revision scheme, planning operation flow, digital processing, thematic analysis and inquiry, and preparation of the chart of reserved land resources. The developed system has been successfully applied to the land-use planning and management work of Longquanyi District, Chengdu, China. It may provide a reference for development of geographic information system （GIS） for land and resources.
文摘Management Information System provides an effective way for enterprises to improve their competitive abilities. It presents a framework for improving the management models through the design and implementation of effective and high-quality MIS. So it is very important to the modem management of corporations. ERP （Enterprise Resource Planning） system is one of the core parts of MIS, which solves the matter of management model mainly. ERP is a popular method enabling the business processes required to compete with the globalization. The thesis cites SAP R/3 to introduce the general structure and function of ERP. Global Enterprise Resource Planning Implementation is increasingly becoming the successful choice of MIS.
文摘The developmental activities, particularly the construction of hydroelectric projects are causing a great loss of biodiversity in the Indian Himalayan Region. The Himaehal Pradesh, a part of IHR is well known for the development of hydroelectric projects. The Parbati H.E. Project is amongst the major projects of the State. The different stages of the project are all causing loss of biodiversity of the area. Stage Ⅲ of the Parbati H.E. Project is a run of the river scheme on the Sainj River downstream of Power House of Parbati H.E. Project Stage Ⅱ. The project shall utilize regulated discharge of Parbati H.E. Project Stage Ⅱ and inflow of River Sainj for power generation, and has been contemplated as a peaking station operating in tandem with Stage Ⅱ. The present study has been undertaken to see the impact of hydroelectric project on the biodiversity, particularly on medicinal plants. A total of 104 species of medicinal plants, belonging to different life forms, i.e., trees （23 spp.）, shrubs （22 spp.）, herbs （57 spp.） and ferns （2 spp.） were recorded. The species have been analyzed and studied for their distribution, classification, altitudinal zones, part （s） used, indigenous uses, nativity, endemism and rarity.Different parts of these species, such as whole plants, roots （including rhizomes and tubers）, leaves, flowers, fruits, seeds, stems, barks, spikes, nuts and insect galls are used by the inhabitants for curing various diseases and ailments. 3o species are native to the Himalayan region, 9 species native to the Himalayan region and adjacent countries also and 65 species are non-natives. 9 species are near endemics. Considering the whole Himalaya as a biogeographie unit （sensu lato）, the near endemics are endemic to the Himalaya. Among these species, Zanthoxylum armature is categorized as Endangered and Valeriana wallichii as Vulnerable. Hedychium spicatum, Rhus javanica, Berberis lycium, Thalictrum foliolossum, Salvia lanata, Rubia cordifolia and Bergenia ligulata may be considered as threatened species due to their over exploitation for trade. 90 species are propagated by seeds, 8 species by seeds and rhizomes/roots/tubers, 4 species by seeds and cuttings, and 2 species by sori. A management plan for the cultivation and conservation of the medicinal plants in the dam submergence area, and the commercially viable medicinal plants with high value in the catchment area is suggested.
基金the Deanship of Scientific Research at King Saud University for funding this work through research Group No.RG-1441-331.
文摘Simulation is a powerful tool for improving,evaluating and analyzing the performance of new and existing systems.Traffic simulators provide tools for studying transportation systems in smart cities as they describe the evolution of traffic to the highest level of detail.There are many types of traffic simulators that allow simulating traffic in modern cities.The most popular traffic simulation approach is the microscopic traffic simulation because of its ability to model traffic in a realistic manner.In many cities of Saudi Arabia,traffic management represents a major challenge as a result of expansion in traffic demands and increasing number of incidents.Unfortunately,employing simulation to provide effective traffic management for local scenarios in Saudi Arabia is limited to a number of commercial products in both public and private sectors.Commercial simulators are usually expensive,closed source and inflexible as they allow limited functionalities.In this project,we developed a local traffic simulator“KSUtraffic”for traffic modeling,planning and analysis with respect to different traffic control strategies and considerations.We modeled information specified by GIS and real traffic data.Furthermore,we designed experiments that manipulate simulation parameters and the underlying area.KSUTraffic visualizes traffic and provides statistical results on the simulated traffic which would help to improve traffic management and efficiency.
基金National Natural Science Foundation of China(NSFC),Grant/Award Number:41850410497National Key R&D Program of China,Grant/Award Number:2019YFC1510400+5 种基金National Natural Science Foundation of China(NSFC)Youth Project,Grant/Award Number:51909126University of Nottingham(UNUK)Project,Grant/Award Number:E01200500006Institute of Asia Pacific Studies Research Funded for the Environmental Security and SustainabilityCultural and Creative Industries Research Priority AreasFaculty of Science and Engineering(FTSE)Postgraduate Research Scholarship of University of Nottingham Ningbo ChinaGuizhou Science and Technology Planning of Project,Grant/Award Number:20192879。
文摘Catchment floods are more challenging due to intensive urbanization and climate change.Enlightened by the Low Impact Development(LID),China initiated the Sponge City Program(SCP)to transform Urban Flood Management(UFM)to be more environmentally friendly in 2013.The China National Government(CNG)has subsidized municipal SCP facilities to enhance urban flood resilience while delivering multiple co‐benefits for urban ecosystems and social well‐being.Recent floods at Schleiden(Germany),Arizona State(USA),and Zhengzhou(China)in 2021 reflected the necessity of Catchment Flood Management(CFM)to cover the whole catchment scale.The SCP,designed to handle small‐scale urban pluvial floods,has brought concerns when facing larger‐scale fluvial floods after the Zhengzhou 2021 flood.Indeed,catchment‐scale Natural Flood Management(NFM)can manage fluvial floods while improving flood adaptations sustainably from upstream to downstream reaches.This research develops a new framework named the Sponge Catchment Management Plan(SCMP),including structural and Nonstructural elements.On the structural side,the SCMP framework integrates NFM with the SCP and Grey Engineering(GE)for reducing the fluvial flood discharge peaks in the whole‐catchment scale.On the nonstructural side,the SCMP encourages collaborative governance,revising technical standards,and improving“bottom‐up”participation.This research used Semi‐Structured Interviews(SSIs)and a Focus Group Approach(FGA)to explore 62 professional and Nonprofessional stakeholders’perspectives on the SCMP framework.Some professional respondents did not know much about the NFM and were worried about the effectiveness of this practice.But most interviewees supported the SCMP pilot work and shared the co‐benefits from the NFM.This case study at the SW China,Guiyang,could be a lesson to encourage other Chinese cities further implement SCP to improve catchment‐scale flood resilience.
文摘Objective To study the origin and development,framework and content of the EU-RMP(European Drug Risk Management Plan)so as to provide a reference for China’s drug risk management plan(RMP).Methods Literature research and comparative research were used in this paper.Through searching Chinese and foreign literature,the website of European Medicines Agency(EMA)and the Guideline on Good Pharmacovigilance Practices(GVP),in-depth understanding of the EU-RMP content and requirements,some lessons were extracted for our reference.Results and Conclusion All departments should cooperate closely in the preparation of RMP in China.Then,the risk control measures should be further enriched to reduce the risks.Besides,the rules for implementing RMP should be clarified to promote the risk management of the whole life cycle of drugs and maintain the safety of patients’medication.
文摘The General Office of the State Council released the 13th Five-Year Plan for China's National Emergency System Construction(Plan for short).According to the Plan,China's emergency management laws and regulations and standards system need to be further improved and the basic capabilities of emergency management should continue to be enhanced.
基金This work was supported by the EPSRC,UK funded Centre for Urban Sustainability and Resilience(Grant EP/G037698/1).
文摘The necessity to recognize the subsurface or underground and all its current and potential uses as part of our urban environment,to integrate this into urban planning and governance,and to foster conscious allocation of subsurface space has been increasingly recognized over the last century.At the same time,systems thinking as a‘buzz-word’has gained relevance for approaching complex problem areas in all kinds of disciplines including those preoccupied with the subsurface.This paper reviews the literature about urban underground planning through a systems-lens.To set this in context,it is outlined how organizational principles for the urban subsurface have evolved,and the main aspects of systems thinking are introduced followed by a discussion of how this thinking could be applied to the urban underground.Strategies and tools presented in the recent literature in the field are then reviewed based on this perspective,asking how systemic the proposed strategies and tools are when the local geology,as well as legal and institutional settings are accepted as a baseline for analysis or intervention.Systemic approaches built on this premise have the potential to capture existing and evolving complexities,foster a better understanding of the value of subsurface space for a city and ultimately enable an efficient and fair allocation of underground space.However,propositions for holistic solutions remain dispersed,interventions often remain based in an engineering mindset,and a shift in mind-set remains a challenge.More research in collaboration with local and regional administrations or authorities based on systems thinking frameworks could help to facilitate this shift.
文摘This paper introduces the energy consumption status in China, elaborate the affects of the unreasonable energy consumption structure on energy environment and sustainable development of economy. Simultaneously, it points out the solution, i.e., to implement integrated resources planning (IRP)/demand side management (DSM), and gives some recommendations on the way of implementing IRP/DSM.
文摘Exercise training provides physiological benefits for both improving athletic performance and maintaining good health. Different exercise training modalities and strategies exist. Two common exercise strategies are high-intensity interval training （HIIT） and moderate-intensity continuous exercise training （MCT）. HIIT was first used early in the 20th century and popularized later that century for improving performance of Olympic athletes. The primary premise underlying HIIT is that, compared to energy expenditure-matched MCT, a greater amount of work is performed at a higher intensity during a single exercise session which is achieved by alternating high-intensity exercise intervals with low-intensity exercise or rest intervals. Emerging research suggests that this same training method can provide beneficial effects for patients with a chronic disease and should be included in the comprehensive medical management plan. Accordingly, a major consideration in developing an individual exercise prescription for a patient with a chronic disease is the selection of an appropriate exercise strategy. In order to maximize exercise training benefits, this strategy should be tailored to the individual＇s need. The focus of this paper is to provide a brief summary of the current literature re^ardin~ the use of HIIT to enhance the fimctional capacity of individuals with cardiovascular, pulmonary, and diabetes diseases.
文摘A GIS is proposed as a tool for the managing plan for the Antarctic specially managed area (ASMA) in Admiralty Bay.The ASMA comprises the area considered to be within the glacial drainage basin of the bay.Furthermore,it includes part of SSSI No.8 adjacent to the area but outside of the glacial drainage basin.Three stations and six refuges are located in the area.Using a SPOT satellite image map,the limits of the ASMA are marked and its area is re_calculated.It consists of 362 km 2,including 186 km 2 island ice field and small cirque glaciers and 32 km 2 ice_free field.The rest comprises water of the bay and a small adjacent area (8 km 2) of the Bransfield Strait.The ASMA_GIS will consists of 12 data layers ranging from the physiographic settings to the biological and administrative features.All data will be implemented into Arc/Info GIS according to the cartographic guidelines of the SCAR WG_GGI.First,five plans of information will be realised using a topographic database compiled from various sources and data from the revised bathymetric chart published by the Brazilian Navy Hydrographic Survey and also including: 1) Limits of the ASMA and protected areas;2) Glaciological features (e.g.drainage basin limits) and 3) Human presence (e.g.stations and historical sites).These basic GIS layers will be operational in early 2001.Then,additional data on the remaining layers (e.g.hydrology,geology and geomorphology) will be included from published sources. The ASMA_GIS will form an important database for environmental monitoring and studies surveying temporal changes of features such as glacier front positions or bird breading sites.
文摘This paper examines task partition problem in a Multiagent based Distributed Open Computing Environment Model(MDOCEM). We first present a formal method to describe the task partition problem, then give a heuristic algorithm to solve the task partition problem that gives an approximate optimum solution.
