Ecological security assessment and early warning research possess the attributes of spatiality, non-linearity and randomicity, so we must process much spatial information. Spatial analysis and data management are the ...Ecological security assessment and early warning research possess the attributes of spatiality, non-linearity and randomicity, so we must process much spatial information. Spatial analysis and data management are the advantages of GIS, which can define distribution trend and spatial relations of environmental factors, and show ecological security pattern graphically. Spatial differences of ecological security assessment based on GIS are discussed in this paper, of which the middle and lower reaches of the Liaohe River is taken as a study case. First, to work out pressure-state-response (P-S-R) assessment indicators system, and investigate in person and gather information; second, to digitize the watershed; third, to quantize and calculate by the fuzzy method; last, to construct GIS grid database, and expound spatial differences of ecological security by GIS interpolation and assembly analysis.展开更多
Integrated power-gas systems(IPGS)have developed critical infrastructure in integrated energy systems.Moreover,various extreme weather events with low probability and high risk have seriously affected the stable opera...Integrated power-gas systems(IPGS)have developed critical infrastructure in integrated energy systems.Moreover,various extreme weather events with low probability and high risk have seriously affected the stable operation of IPGSs.Due to close interconnectedness through coupling elements between the power system(PS)and natural gas system(NGS)when a disturbance happens in one system,a series of complicated sequences of dependent events may follow in another system.Especially under extreme conditions,this coupling can lead to a dramatic degradation of system performance,resulting in catastrophic failures.Therefore,there is an urgent need to model and evaluate resilience of IPGSs under extreme weather.Following this development trend,an integrated model for resilience evaluation of IPGS is proposed under extreme weather events focusing on windstorms.First,a framework of IPGS is proposed to describe states of the system at different stages under disaster conditions.Furthermore,an evaluation model considering cascading effects is used to quantify the impact of windstorms on NGS and PS.Meanwhile,a Monte Carlo simulation(MCS)technique is utilized to characterize chaotic fault of components.Moreover,time-dependent nodal and system resilience indices for IPGS are proposed to display impacts of windstorms.Numerical results on the IPGS test system demonstrate the proposed methods.展开更多
The Denglou Cape, southwest of the Leizhou Peninsula, is the most typical tropical coast in the continent of China.The coastal geomorphic development basics of the geology and Quaternary environment change are discus...The Denglou Cape, southwest of the Leizhou Peninsula, is the most typical tropical coast in the continent of China.The coastal geomorphic development basics of the geology and Quaternary environment change are discussed. Aerial photograph interpretation with fieldwork is applied to draw the outlines of geomorphic types. Based on the investigative data, the exogenic forces and marine organism conditions concerning tropical coast development in the area are expounded, and coastal dynamo-deposition geomorphic bodies are analysed, mainly with sea cliff-abrasion platform,barrier-lagoon system, modern beach, coral reef and mangrove tidal flat, and the general process of coastal evolution at this area, as well as coastline changes since middle Holocene transgression.展开更多
Background:Measuring the performance of a health system is an essential requirement in creating systems that generate efficient,equitable,patient-focused,accessible and sustainable results.A fundamental requirement fo...Background:Measuring the performance of a health system is an essential requirement in creating systems that generate efficient,equitable,patient-focused,accessible and sustainable results.A fundamental requirement for a performance measurement system is the development of an assessment framework within which specific performance measures could be defined and applied regularly.This paper examines the comprehensiveness of Ghana’s health system assessment framework called the Holistic Assessment Tool in relation to some of the internationally recognized frameworks.The paper also analyzes trends in the performance of the health system to understand whether or not an improvement has been recorded following the adoption and implementation of the Holistic Assessment Tool.Methods:Mainly secondary data were used in this analysis.Searches were conducted on Google Scholar,PubMed,Scopus and Science Direct between May and July,2019 for published documents on health system performance assessment.We also obtained unpublished documents from Ghana’s Ministry of Health,Ghana Health Service website,and Ghana Statistical Service database.Descriptive statistics were used to examine trends in the performance of the Ghanaian health system.Results:While the tool provides a national framework for evaluating the performance of the Ghana Health system in several domains,the Holistic Assessment Tool does not cover key health system domains such as information systems for health,access to essential medicines,and patient-centeredness.Also,the scope of the assessment program seems limited to the evaluation of the Ministry of Health’s annual plans,programs and projects.However,the health system has recorded improvements in population health indicators,such as life expectancy at birth,infant mortality,under-5 mortality,HIV prevalence and disease burden(in terms of disability adjusted life years).Conclusions:The Holistic Assessment Tool is a useful framework,but needs further refinement,both in scope and in conceptual robustness.Future stu展开更多
文摘Ecological security assessment and early warning research possess the attributes of spatiality, non-linearity and randomicity, so we must process much spatial information. Spatial analysis and data management are the advantages of GIS, which can define distribution trend and spatial relations of environmental factors, and show ecological security pattern graphically. Spatial differences of ecological security assessment based on GIS are discussed in this paper, of which the middle and lower reaches of the Liaohe River is taken as a study case. First, to work out pressure-state-response (P-S-R) assessment indicators system, and investigate in person and gather information; second, to digitize the watershed; third, to quantize and calculate by the fuzzy method; last, to construct GIS grid database, and expound spatial differences of ecological security by GIS interpolation and assembly analysis.
基金supported by the Key Projects of National Natural Science Foundation of China(51936003)。
文摘Integrated power-gas systems(IPGS)have developed critical infrastructure in integrated energy systems.Moreover,various extreme weather events with low probability and high risk have seriously affected the stable operation of IPGSs.Due to close interconnectedness through coupling elements between the power system(PS)and natural gas system(NGS)when a disturbance happens in one system,a series of complicated sequences of dependent events may follow in another system.Especially under extreme conditions,this coupling can lead to a dramatic degradation of system performance,resulting in catastrophic failures.Therefore,there is an urgent need to model and evaluate resilience of IPGSs under extreme weather.Following this development trend,an integrated model for resilience evaluation of IPGS is proposed under extreme weather events focusing on windstorms.First,a framework of IPGS is proposed to describe states of the system at different stages under disaster conditions.Furthermore,an evaluation model considering cascading effects is used to quantify the impact of windstorms on NGS and PS.Meanwhile,a Monte Carlo simulation(MCS)technique is utilized to characterize chaotic fault of components.Moreover,time-dependent nodal and system resilience indices for IPGS are proposed to display impacts of windstorms.Numerical results on the IPGS test system demonstrate the proposed methods.
文摘The Denglou Cape, southwest of the Leizhou Peninsula, is the most typical tropical coast in the continent of China.The coastal geomorphic development basics of the geology and Quaternary environment change are discussed. Aerial photograph interpretation with fieldwork is applied to draw the outlines of geomorphic types. Based on the investigative data, the exogenic forces and marine organism conditions concerning tropical coast development in the area are expounded, and coastal dynamo-deposition geomorphic bodies are analysed, mainly with sea cliff-abrasion platform,barrier-lagoon system, modern beach, coral reef and mangrove tidal flat, and the general process of coastal evolution at this area, as well as coastline changes since middle Holocene transgression.
文摘Background:Measuring the performance of a health system is an essential requirement in creating systems that generate efficient,equitable,patient-focused,accessible and sustainable results.A fundamental requirement for a performance measurement system is the development of an assessment framework within which specific performance measures could be defined and applied regularly.This paper examines the comprehensiveness of Ghana’s health system assessment framework called the Holistic Assessment Tool in relation to some of the internationally recognized frameworks.The paper also analyzes trends in the performance of the health system to understand whether or not an improvement has been recorded following the adoption and implementation of the Holistic Assessment Tool.Methods:Mainly secondary data were used in this analysis.Searches were conducted on Google Scholar,PubMed,Scopus and Science Direct between May and July,2019 for published documents on health system performance assessment.We also obtained unpublished documents from Ghana’s Ministry of Health,Ghana Health Service website,and Ghana Statistical Service database.Descriptive statistics were used to examine trends in the performance of the Ghanaian health system.Results:While the tool provides a national framework for evaluating the performance of the Ghana Health system in several domains,the Holistic Assessment Tool does not cover key health system domains such as information systems for health,access to essential medicines,and patient-centeredness.Also,the scope of the assessment program seems limited to the evaluation of the Ministry of Health’s annual plans,programs and projects.However,the health system has recorded improvements in population health indicators,such as life expectancy at birth,infant mortality,under-5 mortality,HIV prevalence and disease burden(in terms of disability adjusted life years).Conclusions:The Holistic Assessment Tool is a useful framework,but needs further refinement,both in scope and in conceptual robustness.Future stu
