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Graph Theory Based N-1 Transmission Contingency Selection and Its Application in Security-constrained Unit Commitment

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Journal of Modern Power Systems and Clean Energy 2021年第6期9卷 1458-1467页

作者： Lu Nan Yikui Liu Lei Wu Tianqi Liu Chuan He College of Electrical Engineering Sichuan University the Department of Electrical and Computer Engineering Stevens Institute of Technology Department of Electrical and Computer Engineering Stevens Institute of Technology

Contingency analysis is an important building block in the stability and reliability analysis of power grid operations. However, due to the large number of transmission lines,in practice only a limited number of contingencies could be evaluated. This paper proposes a graph theory based N-1 contingency selection method to effectively identify the most critical contingencies, which can be used in security-constrained unit commitment(SCUC) problems to derive secure and economic operation decisions of the power grid. Specifically, the power flow transferring path identification algorithm and the vulnerability index are put forward to rank individual contingencies according to potential transmission line overloads. Effectiveness of the proposed N-1 contingency selection method is quantified by applying the corresponding SCUC solution to the full N-1 security evaluation, i. e., quantifying total post-contingency generation-load imbalance in all N-1 contingencies. Numerical results on several benchmark IEEE systems, including5-bus, 24-bus, and 118-bus systems, show effectiveness of the proposed method. Compared with existing contingency selection methods which usually resort to full power flow calculations,the proposed method relies on power gird topology to effectively identify critical contingencies for facilitating the optimal scheduling of SCUC problems.

关键词： Concentric relaxation contingency analysis graph theory security-constrained unit commitment(SCUC) shortest path vulnerability index

vulnerability analysis of smallholder farmers to climate variability and change: an agroecological system-based approach in the Fincha’a sub-basin of the upper Blue Nile Basin of Ethiopia

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Ecological Processes 2019年第1期8卷 49-66页

作者： Israel Tessema Belay Simane Center for Environment and Development College of Development StudiesAddis Ababa UniversityAddis AbabaEthiopia Environmental Engineering College of Biological and Chemical EngineeringAddis Ababa Science and Technology UniversityAddis AbabaEthiopia

Background:Ethiopia is frequently cited as a country that is highly vulnerable to climate variability and change.The country’s high vulnerability arises mostly from climate-sensitive agricultural sector that suffers a lot from risks associated with rainfall variability.The vulnerability factors(exposure,sensitivity,and adaptive capacity)of the agricultural livelihoods to climate variability and change differ across agro-ecological systems(AESs).Therefore,the aim of this study was to analyze AES-specific vulnerability of smallholder farmers to climate variability and change in the Fincha’a sub-basin.We surveyed 380 respondents from 4 AESs(highland,midland,wetland,and lowland)randomly selected.Furthermore,focus group discussion and key informant interviews were also performed to supplement and substantiate the quantitative data.Livelihood vulnerability index was employed to analyze the levels of smallholders’agriculture vulnerability to climate variability and change.Data on socioeconomic and biophysical attribute were collected and combined into the indices and vulnerability score was calculated for each agro-ecological system.Results:Considerable variation was observed across the agro-ecological systems in profile,indicator,and the three livelihood vulnerability indices-Intergovernmental Panel on Climate Change dimensions(exposure,sensitivity,and adaptive capacity)of vulnerability.The lowland AES exhibited higher exposure,low adaptive capacity,and high vulnerability,while the midland AES demonstrated lower exposure,higher adaptive capacity,and lower vulnerability.The wetland and highland AESs scored intermediate results.Conclusion:Our results suggest that resilience-building adaptation strategies are vital to reduce the vulnerability of smallholder farmers.The measures taken should consider site-specific agro-ecological system requirements to reduce the vulnerability of smallholder mixed crop-livestock agriculture system.Since the approach based on the long-term realization of the community,any strategy designed

关键词： vulnerability index Exposure Sensitivity Adaptation capacity Fincha’a sub-basin

Rural households’ livelihood vulnerability to climate variability and extremes: a livelihood zone-based approach in the Northeastern Highlands of Ethiopia

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Ecological Processes 2021年第1期10卷 749-771页

作者： Abebe Arega Mekonen Arega Bazezew Berlie Department of Geography and Environmental Studies Bahir Dar UniversityP.O.Box 79Bahir DarEthiopia Department of Geography and Environmental Studies Debremarkos UniversityP.O.Box 269DebremarkosEthiopia

Background:The adverse effects of climate variability and extremes exert increasing pressure on rural farm households whose livelihoods are dependent on nature.However,integrated and area-specific vulnerability assessments in Ethiopia in general and the study area,in particular,are scarce and insufficient for policy implications.Therefore,this study aims to quantify,map,classify,and prioritize the level of vulnerability in terms of the components of exposure,sensitivity,and adaptive capacity in the Northeastern Highlands of Ethiopia.The study area is divided into six livelihood zones,namely,Abay-Beshilo Basin(ABB),South Wollo and Oromia eastern lowland sorghum and cattle(SWS),Chefa Valley(CHV),Meher-Belg,Belg,and Meher.A total of 361 sample households were selected using proportional probability sampling techniques.Survey questionnaire,key informant interview,and focus group discussions were used to collect the necessary data.Rainfall and temperature data were also used.Following the IPCC’s climate change vulnerability assessment approach,the climate vulnerability index(CVI)framework of Sullivan and Meigh’s model was used to assess the relative vulnerability of livelihoods of rural households.Twenty-four vulnerability indicators were identified for exposure,sensitivity,and adaptive capacity components.In this regard,Iyengar and Sudarshan’s unequal weighting system was applied to assign a weight to indicators.Results:The results revealed that Belg and Meher were found to be the highest exposure livelihood zones to vulnerability with an aggregated value of 0.71.Equally,SWS,ABB,Belg,and CHV livelihood zones showed moderate level of sensitivity to vulnerability with an aggregated value between 0.45 and 0.60.The study noted that livelihood zone of Belg(0.75)was found to be at high level of livelihood vulnerability.ABB(0.57)and CHV(0.45)were at a moderate level of livelihood vulnerability while Meher-Belg(0.22)was the least vulnerable livelihood zone due to a high level of adaptive capacity such as infrastructure,asset

关键词： Exposure Sensitivity Adaptive capacity vulnerability index Sullivan and Meigh’s model Ethiopia

vulnerability to Earthquake Hazard:Bucharest Case Study,Romania

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International Journal of Disaster Risk Science 2017年第2期8卷 182-195页

作者： Iuliana Armas Dragos Toma-Danila Radu Ionescu Alexandru Gavris Department of Geomorphology-Pedology-Geomatics Faculty of GeographyUniversity of Bucharest National Institute for Earth Physics Department of Tourism and Geography Bucharest University of Economic Studies

Recent seismic events show that urban areas are increasingly vulnerable to seismic damage,which leads to unprecedented levels of risk.Cities are complex systems and as such their analysis requires a good understanding of the interactions between space and the socioeconomic variables characteristic of the inhabitants of urban space.There is a clear need to develop and test detailed models that describe the behavior of these interactions under seismic impact.This article develops an overall vulnerability index to seismic hazard based on a spatial approach applied to Bucharest,Romania,the most earthquake-prone capital in the European Union.The methodology relies on:(1) spatial post-processed socioeconomic data from the2011 Romanian census through multicriteria analysis;and(2) analytical methods(the Improved Displacement Coefficient Method and custom-defined vulnerability functions)for estimating damage patterns,incorporated in a GIS environment.We computed vulnerability indices for the128 census tracts of the city.Model sensitivity assessment tested the robustness of spatially identified patterns of building vulnerability in the face of uncertainty in model inputs.The results show that useful seismic vulnerability indices can be obtained through interdisciplinaryapproaches that enhance less detailed datasets,which leads lead to better targeted mitigation efforts.

关键词： Bucharest Romania Seismic loss estimation Seismic risk Spatial multicriteria analysis vulnerability index

Liquefaction assessment using microtremor measurement, conventional method and artificial neural network （Case study： Babol, Iran）

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Frontiers of Structural and Civil Engineering 2014年第3期8卷 292-307页

作者： Sadegh REZAEI Asskar Janalizadeh CHOOBBASTI Department of Civil Engineering Babol University of Technology Babol P O. Box 484 Iran

Recent researchers have discovered microtremor applications for evaluating the liquefaction potential. Microtremor measurement is a fast, applicable and cost-effective method with extensive applications. In the present research the liquefaction potential has been reviewed by utilization of microtremor measurement results in Babol city. For this purpose microtremor measurements were performed at 60 measurement stations and the data were analyzed by suing Nakmaura＇s method. By using the fundamental frequency and amplification factor, the value of vulnerability index （Kg） was calculated and the liquefaction potential has been evaluated. To control the accuracy of this method, its output has been compared with the results of Seed and Idriss [1] method in 30 excavated boreholes within the study area. Also, the results obtained by the artificial neural network （ANN） were compared with microtremor measurement. Regarding the results of these three methods, it was concluded that the threshold value of liquefaction potential is Kg = 5. On the basis of the analysis performed in this research it is concluded that microtremors have the capability of assessing the liquefaction potential with desirable accuracy.

关键词： liquefaction microtremor vulnerability index artificial neural networks （ANN） microzonation

Risk factors for schistosomiasis in an urban area in northern Cote d’Ivoire

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Infectious Diseases of Poverty 2018年第1期7卷 460-471页

作者： Richard K.M’Bra Brama Kone Yapi G.Yapi Kigbafori D.Silue Ibrahima Sy Danielle Vienneau Nagnin Soro Gueladio Cisse Jurg Utzinger Unitede Formation et de Recherche des Sciences de la Terre et des Ressources Minieres Universite Felix Houphouet-Boigny01 BP V 34Abidjan 01Cpte d’Ivoire Centre Suisse de Recherches Scientifiques en Cpte d’Ivoire 01 BP 1303Abidjan 01Cote d’Ivoire Swiss Tropical and Public Health Institute P.O.BoxCH-4002BaselSwitzerland University of Basel P.O.BoxCH-4003BaselSwitzerland Institut de Gestion Agropastorale UniversitéPéléforo Gon CoulibalyBP 1328KorhogoCote d’Ivoire Centre d’Entomologie Medicale et Veterinaire Universite Alassane Ouattara27 BP 529Abidjan 27Cote d’Ivoire Unitede Formation et de Recherche Biosciences Universite Felix Houphouet-Boigny22 BP 522Abidjan 22Cote d’Ivoire Centre de Suivi Ecologique BP 15532DakarSenegal.

Background:Schistosomiasis is a water-based disease transmitted by trematodes belonging to the genus Schistosoma.The aim of this study was to assess the relationship between the prevalence of schistosomiasis and access to water,sanitation and hygiene(WASH)and environmental and socioeconomic factors in the city of Korhogo,northern Côte d'Ivoire.Methods:A cross-sectional study including 728 randomly selected households was conducted in Korhogo in March 2015.The heads of the households were interviewed about access to WASH and environmental and socioeconomic factors.All children abed between 5 and 15 years living in the households were selected to provide stool and urine samples for parasitological diagnosis of Schistosoma mansoni and Schistosoma haematobium infection.The relationship between infection with S.mansoni and potential risk factors was analysed by a mixed logistic regression model with‘household’as a random factor.Likelihood ratio tests were used to identify factors that were significantly associated with a Schistosoma spp.infection.Results:The overall prevalence of schistosomiasis among school-aged children in Korhogo was 1.9%(45/2341)composed of 0.3%(3/1248)S.haematobium and 3.5%(42/1202)S.mansoni.Due to the low prevalence of S.haematobium infection,risk factor analysis was limited to S.mansoni.Boys were 7.8 times more likely to be infected with S.mansoni than girls.Children between 10 and 15 years of age were 3.8 times more likely to be infected than their younger counterparts aged 5-10 years.Moreover,living in a house further away from a water access point(odds ratio[OR]=0.29,95%confidence interval[CI]:0.13-0.70)and abstaining from swimming in open freshwater bodies(OR=0.16,95%CI:0.04-0.56)were significantly associated with decreased odds of S.mansoni infection.The socioeconomic status did not appear to influence the prevalence of S.mansoni.Conclusions:A strategy to reduce the incidence of schistosomiasis should focus on health education to change the behaviour of populations at risk and encourage co

关键词： Cote d’Ivoire Schistosomiasis School-aged children Urban agriculture vulnerability index Water Sanitation and Hygiene(WASH)

Effects of moxibustion or moxa smoke on serum lipids and carotid plaque stability in atherosclerotic mice

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Journal of Traditional Chinese Medical Sciences 2020年第3期7卷 325-332页

作者： Rui Zhang Lue Ha Rui He Yueping Huang Hao Wang Baixiao Zhao School of Acupuncture-Moxibustion and Tuina Beijing University of Chinese MedicineBeijing100029China

Objective:To observe the effects of moxibustion or moxa smoke on serum lipids,aorta and liver pathology,and carotid plaque stability in atherosclerosis.Methods:Fifty-four 8-week-old ApoE^-/- mice were randomly divided into three groups(untreated,moxibustion,and moxa smoke)and received a high-fat diet.Eighteen wild-type C57 BL/6 mice of the same age were used as controls.The intervention(none,moxibustion between the nipples,or 10 e15 mg/m^3 moxa smoke)was applied to restrained mice 20 min per day,six days per week,for 12 weeks.At the end of the experimental period,we measured serum lipids and apolipoprotein,stained thoracic aortas and livers to observe pathological changes,and used immunohistochemical staining to assess the levels of a-smooth muscle actin,CD68,tumor necrosis factor-α,nuclear transcription factor-κB,and P38 mitogen-activated protein kinase.We also measured the levels of matrix metalloproteinase-2 and 9 and tissue metalloproteinase inhibitor-1.Results:After 12 weeks,lipid metabolism disorder and atherosclerotic plaques were observed in the ApoE^-/- mice.Moxibustion or moxa smoke reduced the levels of serum total cholesterol,triglycerides,low density lipoprotein,and very low density lipoprotein but did not affect the levels of high density lipoprotein,apolipoprotein A1,or oxidized low density lipoprotein.Moxibustion or moxa smoke suppressed pathological changes in thoracic aortas and livers,increased fiber cap thickness,the fiber cap thickness/intimal medial thickness ratio,and collagen area percentage,and reduced extracellular lipids.Treatment with moxibustion or moxa smoke increased a-smooth muscle actin and reduced CD68 and the vulnerability index,suppressed tumor necrosis factor-α and nuclear transcription factor-κB expression,and did not affect P38 mitogen-activated protein kinase expression.Treatment lowered the levels of matrix metalloproteinase-2 and 9 and increased those of tissue metalloproteinase inhibitor-1.Conclusion:Moxibustion or moxa smoke exert protective effects in serum lipid profi

关键词： Atherosclerosis Matrix metalloproteinase vulnerability index Tissue metalloproteinase inhibitor