The optimal allocation of regulators banks in distribution systems is a merely combinatorial problem in which the best points of installation correspond to the best benefit, considering the admitted objective function...The optimal allocation of regulators banks in distribution systems is a merely combinatorial problem in which the best points of installation correspond to the best benefit, considering the admitted objective function, without violating and operating limits. The objective function must be chosen so that its value represents the operation state of the system. As the problem possesses combinatorial nature, its complexity will increase exponentially with the number of possibilities. Systems with large numbers of nodes and / or with the possibility of installing more than one bank require a large number of calculations to find the solution. An additional issue is the fact that the problem does not have a continuous nature, presenting discontinuity points in the objective function, limiting the application of optimization methods based on gradients. Based on the nature of the problem two optimization methods were used to solve the problem: Genetic Algorithm (GA) and modified Tabu Search (TS). The GA function will scour the search space and find regions with local minima that are candidates to be the solution. On the other hand the TS provides local search in the regions defined by GA so that the overall optimum is achieved.展开更多
An experiment was carried out on a set of fullscale specimens of a non-conventional connection between a concrete column and a composite steel and concrete beam defined on the basis of a number of requirements.The pro...An experiment was carried out on a set of fullscale specimens of a non-conventional connection between a concrete column and a composite steel and concrete beam defined on the basis of a number of requirements.The proposed connection,conceived in the ambit of semirigid joints,is aimed at combining general ease of construction with a highly simplified assembly procedure with a satisfying transmission of hogging moment at supports in continuous beams.For this purpose,the traditional shear studs used at the interface between the steel beam and the upper concrete slab,are also employed at the ends of the steel profiles welded horizontally to the end plates.The test is aimed at investigating the hogging moment response of the connection under incremental loads until failure.展开更多
On 14 March 2019,Zimbabwe was hit by Cyclone Idai,leaving immeasurable destruction of unprecedented magnitude in its wake.In Chimanimani District,many lives were lost,many people were reported missing,and others were ...On 14 March 2019,Zimbabwe was hit by Cyclone Idai,leaving immeasurable destruction of unprecedented magnitude in its wake.In Chimanimani District,many lives were lost,many people were reported missing,and others were displaced.The question that immediately comes to mind is:Was the country prepared to manage the Cyclone Idai disaster?Reflecting on the community experiences,the purpose of this research was to interrogate the strength of the disaster risk reduction legislation and institutions in Zimbabwe in the face of meteorological hazards.The research also evaluated the extent of the impact Cyclone Idai had on the Chimanimani communities and the factors that increased the vulnerability to the cyclone.A mixed method approach that involved 1180 participants was used.The study found that disaster risk management legislation and institutions in Zimbabwe are weak.Cyclone Idai resulted in the loss of many human lives,loss of livelihoods,and massive damage to infrastructure.The cyclone exposed capacity and policy gaps in Zimbabwe’s disaster risk management system.The study makes a number of recommendations,including strengthening disaster legislation and policy,and disaster risk governance.Given the communities’response to the disaster occurrence,the study also recommends strengthening social capital.展开更多
This research aimed to analyze the possibility to estimate and automatically map large areas of soybean cultivation through the use of MODIS(Moderate-Resolution Imaging Spectroradiometer)images.Two major techniques we...This research aimed to analyze the possibility to estimate and automatically map large areas of soybean cultivation through the use of MODIS(Moderate-Resolution Imaging Spectroradiometer)images.Two major techniques were used:GEOgraphic-Object-Based Image Analysis(GEOBIA)and Data Mining(DM).In order to obtain the images,the segmentation algorithm implemented by Definiens Developer was used.A decision tree(DT)was created from a training set previously prepared.Time-series of images from the MODIS sensor aboard the Terra satellite were acquired in order to represent the wide variation of the vegetation pattern along the soybean crop cycle.The time-series data were used only for the CEI index.Furthermore,to compare the results obtained from GEOBIA,the slicing technique was used at the CEI level.After the training,the DT was applied to the vegetation indices generating the thematic map of the spatial distribution of soybean.In accordance with the error matrix and kappa parameter analysis,tests for statistical significance were created.Results indicate that the classification achieved by Kappa coefficients is 0.76.In short,the obtained results proved that combining vegetation indices and time-series data using GEOBIA return promising results for mapping soybean plantation on a regional scale.展开更多
文摘The optimal allocation of regulators banks in distribution systems is a merely combinatorial problem in which the best points of installation correspond to the best benefit, considering the admitted objective function, without violating and operating limits. The objective function must be chosen so that its value represents the operation state of the system. As the problem possesses combinatorial nature, its complexity will increase exponentially with the number of possibilities. Systems with large numbers of nodes and / or with the possibility of installing more than one bank require a large number of calculations to find the solution. An additional issue is the fact that the problem does not have a continuous nature, presenting discontinuity points in the objective function, limiting the application of optimization methods based on gradients. Based on the nature of the problem two optimization methods were used to solve the problem: Genetic Algorithm (GA) and modified Tabu Search (TS). The GA function will scour the search space and find regions with local minima that are candidates to be the solution. On the other hand the TS provides local search in the regions defined by GA so that the overall optimum is achieved.
文摘An experiment was carried out on a set of fullscale specimens of a non-conventional connection between a concrete column and a composite steel and concrete beam defined on the basis of a number of requirements.The proposed connection,conceived in the ambit of semirigid joints,is aimed at combining general ease of construction with a highly simplified assembly procedure with a satisfying transmission of hogging moment at supports in continuous beams.For this purpose,the traditional shear studs used at the interface between the steel beam and the upper concrete slab,are also employed at the ends of the steel profiles welded horizontally to the end plates.The test is aimed at investigating the hogging moment response of the connection under incremental loads until failure.
基金the Tsuro Trust for providing the funding for the research。
文摘On 14 March 2019,Zimbabwe was hit by Cyclone Idai,leaving immeasurable destruction of unprecedented magnitude in its wake.In Chimanimani District,many lives were lost,many people were reported missing,and others were displaced.The question that immediately comes to mind is:Was the country prepared to manage the Cyclone Idai disaster?Reflecting on the community experiences,the purpose of this research was to interrogate the strength of the disaster risk reduction legislation and institutions in Zimbabwe in the face of meteorological hazards.The research also evaluated the extent of the impact Cyclone Idai had on the Chimanimani communities and the factors that increased the vulnerability to the cyclone.A mixed method approach that involved 1180 participants was used.The study found that disaster risk management legislation and institutions in Zimbabwe are weak.Cyclone Idai resulted in the loss of many human lives,loss of livelihoods,and massive damage to infrastructure.The cyclone exposed capacity and policy gaps in Zimbabwe’s disaster risk management system.The study makes a number of recommendations,including strengthening disaster legislation and policy,and disaster risk governance.Given the communities’response to the disaster occurrence,the study also recommends strengthening social capital.
文摘This research aimed to analyze the possibility to estimate and automatically map large areas of soybean cultivation through the use of MODIS(Moderate-Resolution Imaging Spectroradiometer)images.Two major techniques were used:GEOgraphic-Object-Based Image Analysis(GEOBIA)and Data Mining(DM).In order to obtain the images,the segmentation algorithm implemented by Definiens Developer was used.A decision tree(DT)was created from a training set previously prepared.Time-series of images from the MODIS sensor aboard the Terra satellite were acquired in order to represent the wide variation of the vegetation pattern along the soybean crop cycle.The time-series data were used only for the CEI index.Furthermore,to compare the results obtained from GEOBIA,the slicing technique was used at the CEI level.After the training,the DT was applied to the vegetation indices generating the thematic map of the spatial distribution of soybean.In accordance with the error matrix and kappa parameter analysis,tests for statistical significance were created.Results indicate that the classification achieved by Kappa coefficients is 0.76.In short,the obtained results proved that combining vegetation indices and time-series data using GEOBIA return promising results for mapping soybean plantation on a regional scale.
