Pub Date : 2016-06-01DOI: 10.1109/POWERAFRICA.2016.7556599
P. Davison, N. Wade, D. Greenwood
In this paper, we use data mining techniques and formulate suitable assessment metrics to derive estimates of the State of Health (SOH) of stand-alone solar home systems. Data is provided from a company with significant numbers of such systems in Africa. The systems in question contain a PV panel, lead-acid battery and a series of DC loads. Data mining allows us to not only estimate the SOH of the battery, but also infer the health of other system components.
{"title":"Data mining of remote monitored stand-alone solar PV systems for State of Health estimation","authors":"P. Davison, N. Wade, D. Greenwood","doi":"10.1109/POWERAFRICA.2016.7556599","DOIUrl":"https://doi.org/10.1109/POWERAFRICA.2016.7556599","url":null,"abstract":"In this paper, we use data mining techniques and formulate suitable assessment metrics to derive estimates of the State of Health (SOH) of stand-alone solar home systems. Data is provided from a company with significant numbers of such systems in Africa. The systems in question contain a PV panel, lead-acid battery and a series of DC loads. Data mining allows us to not only estimate the SOH of the battery, but also infer the health of other system components.","PeriodicalId":177444,"journal":{"name":"2016 IEEE PES PowerAfrica","volume":"495 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133272939","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-06-01DOI: 10.1109/POWERAFRICA.2016.7556614
Hassan Aliyu, J. Agee
In this paper prediction and dispatch of electric energy from a large wind power plant and a solar thermal plant is proposed. The turbines in the wind power plant shall be grouped according to types, power output and geographic location. Neural Network methods shall be employed to predict the power output from each group and the entire wind farm. The output from each group is connected through an electric heating system to a solar thermal power plant (CSP) system. In this model the wind power plant would be flexible and reconfigurable to meet specific energy requirements of the combined heating system. The wind electric heating system shall operate alongside solar thermal heating system to compliment for periods when wind is insufficient. This model shall mitigate issues of power stability on the grid due to variability and intermittency of wind energy supply.
{"title":"Electric energy from the hybrid wind-solar thermal power plants","authors":"Hassan Aliyu, J. Agee","doi":"10.1109/POWERAFRICA.2016.7556614","DOIUrl":"https://doi.org/10.1109/POWERAFRICA.2016.7556614","url":null,"abstract":"In this paper prediction and dispatch of electric energy from a large wind power plant and a solar thermal plant is proposed. The turbines in the wind power plant shall be grouped according to types, power output and geographic location. Neural Network methods shall be employed to predict the power output from each group and the entire wind farm. The output from each group is connected through an electric heating system to a solar thermal power plant (CSP) system. In this model the wind power plant would be flexible and reconfigurable to meet specific energy requirements of the combined heating system. The wind electric heating system shall operate alongside solar thermal heating system to compliment for periods when wind is insufficient. This model shall mitigate issues of power stability on the grid due to variability and intermittency of wind energy supply.","PeriodicalId":177444,"journal":{"name":"2016 IEEE PES PowerAfrica","volume":"86 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127129790","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-06-01DOI: 10.1109/POWERAFRICA.2016.7556601
Paras Loomba, Sonal Asgotraa, R. Podmore
With the advent of low-cost solar panels, and our ability to generate, store and use direct current (DC) electrical energy locally, DC solar microgrids can act as an ideal solution that can transform energy infrastructure for rural communities to power household use as well as local businesses. The implementation is affordable, safe, simple, flexible and also energy efficient. The DC based off-grid solution capacity can range from 200W to 600W and can support a range of energy efficient DC appliances such as High Lumen LED lights for basic lighting, LED solar lights for community lighting and DC LED Television for community education and recreation. For operation and sustainability of these microgrids, various community based working models can be implemented. The energy access provided through DC Solar microgrids enables villagers to generate income for their families and also helps them improve their education and health quality. With 25%-30% more efficient than AC microgrids, this paper advocates implementation of DC microgrids as an energy efficient off-grid clean energy based decentralized power generation solution for the un electrified remote villages and a technology model that can bring about sustainable rural development.
{"title":"DC solar microgrids — A successful technology for rural sustainable development","authors":"Paras Loomba, Sonal Asgotraa, R. Podmore","doi":"10.1109/POWERAFRICA.2016.7556601","DOIUrl":"https://doi.org/10.1109/POWERAFRICA.2016.7556601","url":null,"abstract":"With the advent of low-cost solar panels, and our ability to generate, store and use direct current (DC) electrical energy locally, DC solar microgrids can act as an ideal solution that can transform energy infrastructure for rural communities to power household use as well as local businesses. The implementation is affordable, safe, simple, flexible and also energy efficient. The DC based off-grid solution capacity can range from 200W to 600W and can support a range of energy efficient DC appliances such as High Lumen LED lights for basic lighting, LED solar lights for community lighting and DC LED Television for community education and recreation. For operation and sustainability of these microgrids, various community based working models can be implemented. The energy access provided through DC Solar microgrids enables villagers to generate income for their families and also helps them improve their education and health quality. With 25%-30% more efficient than AC microgrids, this paper advocates implementation of DC microgrids as an energy efficient off-grid clean energy based decentralized power generation solution for the un electrified remote villages and a technology model that can bring about sustainable rural development.","PeriodicalId":177444,"journal":{"name":"2016 IEEE PES PowerAfrica","volume":"142 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116340846","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-06-01DOI: 10.1109/POWERAFRICA.2016.7556585
Qiniso W. Luthuli, K. Folly
This paper presents a comparative study of short-term load forecasting using Artificial Intelligence (AI) and the conventional approach. A feed-forward, multilayer artificial neural network (ANN) was employed to provide a 24-hour load demand forecast. In this model, historical data, weather information, day types and special calendar days were considered. The forecasted results using AI were compared with those of conventional method. From the simulations it is found that the maximum forecasting percentage error for AI is approximately 5.5% as opposed to 15.96% for the conventional approach.
{"title":"Short term load forecasting using artificial intelligence","authors":"Qiniso W. Luthuli, K. Folly","doi":"10.1109/POWERAFRICA.2016.7556585","DOIUrl":"https://doi.org/10.1109/POWERAFRICA.2016.7556585","url":null,"abstract":"This paper presents a comparative study of short-term load forecasting using Artificial Intelligence (AI) and the conventional approach. A feed-forward, multilayer artificial neural network (ANN) was employed to provide a 24-hour load demand forecast. In this model, historical data, weather information, day types and special calendar days were considered. The forecasted results using AI were compared with those of conventional method. From the simulations it is found that the maximum forecasting percentage error for AI is approximately 5.5% as opposed to 15.96% for the conventional approach.","PeriodicalId":177444,"journal":{"name":"2016 IEEE PES PowerAfrica","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129544965","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-06-01DOI: 10.1109/POWERAFRICA.2016.7556619
Kazeza Wingi Hugues, S. Daniel Chowdhury
Africa is the major world region in which populations are deeply affected by water and electricity supply shortages, in spite being blessed with the highest world water aquifer reserves as well as advantageous solar irradiance that encourages harvesting of electricity using photovoltaic cells. This paper deals with the design and performances analysis of a three phase Quasi Z Source Inverter (QZSI) to ensure efficient water and electricity supply while mitigating the effect of greenhouse gases, all this in an African context. The QZSI will simultaneously supply the motor pump set, extract the maximum power (MPP) from photovoltaic arrays as well as supply an auxiliary AC load under suitable predefined condition. The MPP will be tracked by an adaptive variable step size fuzzy logic based incremental conductance MPPT algorithm. The designed system has been developed and implemented in Matlab Simulink. Results shows that with this single stage power converter, the system can at once drive a motor pump set when the water level in the storage tank is at the lower threshold and power up AC loads when the water tank is full. The effectiveness and robustness of the proposed method in increasing performances of the water pumping and three phase AC power generation has been validated, hence the system is susceptible allowing more people accessing to water and electricity supply services.
{"title":"An African solution for water and electricity supply, using a standalone photovoltaic based Quasi Z Source Inverter","authors":"Kazeza Wingi Hugues, S. Daniel Chowdhury","doi":"10.1109/POWERAFRICA.2016.7556619","DOIUrl":"https://doi.org/10.1109/POWERAFRICA.2016.7556619","url":null,"abstract":"Africa is the major world region in which populations are deeply affected by water and electricity supply shortages, in spite being blessed with the highest world water aquifer reserves as well as advantageous solar irradiance that encourages harvesting of electricity using photovoltaic cells. This paper deals with the design and performances analysis of a three phase Quasi Z Source Inverter (QZSI) to ensure efficient water and electricity supply while mitigating the effect of greenhouse gases, all this in an African context. The QZSI will simultaneously supply the motor pump set, extract the maximum power (MPP) from photovoltaic arrays as well as supply an auxiliary AC load under suitable predefined condition. The MPP will be tracked by an adaptive variable step size fuzzy logic based incremental conductance MPPT algorithm. The designed system has been developed and implemented in Matlab Simulink. Results shows that with this single stage power converter, the system can at once drive a motor pump set when the water level in the storage tank is at the lower threshold and power up AC loads when the water tank is full. The effectiveness and robustness of the proposed method in increasing performances of the water pumping and three phase AC power generation has been validated, hence the system is susceptible allowing more people accessing to water and electricity supply services.","PeriodicalId":177444,"journal":{"name":"2016 IEEE PES PowerAfrica","volume":"9 3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130045907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-06-01DOI: 10.1109/POWERAFRICA.2016.7556580
M. Gizaw, I. Davidson, R. Loubser, G. Bright
The vibration level of an Optical Ground Wire (OPGW) with a Multi-Response Stockbridge Damper (MRSD) strung at the tension value of catenary 2100m, is analyzed by using laboratory test result in combination with the endurance limit approach. The effect of the damper counter weight orientation, MRSD with low-mass and bolted clamp were studied in refining the stress state of the OPGW. The result enables transmission lines designers to use the tension value to string the OPGW with MRSD which is free and safe from fatigue failure.
{"title":"Analyses of the vibration level of an OPGW at the catenary value of 2100m with multi-response stockbridge dampers","authors":"M. Gizaw, I. Davidson, R. Loubser, G. Bright","doi":"10.1109/POWERAFRICA.2016.7556580","DOIUrl":"https://doi.org/10.1109/POWERAFRICA.2016.7556580","url":null,"abstract":"The vibration level of an Optical Ground Wire (OPGW) with a Multi-Response Stockbridge Damper (MRSD) strung at the tension value of catenary 2100m, is analyzed by using laboratory test result in combination with the endurance limit approach. The effect of the damper counter weight orientation, MRSD with low-mass and bolted clamp were studied in refining the stress state of the OPGW. The result enables transmission lines designers to use the tension value to string the OPGW with MRSD which is free and safe from fatigue failure.","PeriodicalId":177444,"journal":{"name":"2016 IEEE PES PowerAfrica","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128878659","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-06-01DOI: 10.1109/POWERAFRICA.2016.7556600
J. Momoh, S. S. Reddy
This paper presents a research and education based platform of simple Microgrid (MG) and Hardware-In-Loop (HIL) modern PC based Real Time Digital Simulator (RTDS) to simulate the MG platform set up. The value of simulator is evaluated using different functions for performance analysis of MG test bed under different simulation environment. The Simulink software is use to build the detailed model of MG and controller which can be used to solve the voltage/VAr and frequency control problems offline. The issues of MG control as a single agent or value of multi-agent decision support are discussed. The performance of controls is simulated online using the OPAL RT and eMAGAsim for economic selection and effectiveness of the controls, which will be sufficient for enhancing the design and capacity of MG for meeting its reliable and efficient power supply objectives under different contingencies. The developed test bed capability has been demonstrated by using it for validating different controls system for securing the MG network under different contingencies.
{"title":"Value of Hardware-In-Loop for experimenting microgrid performance system studies","authors":"J. Momoh, S. S. Reddy","doi":"10.1109/POWERAFRICA.2016.7556600","DOIUrl":"https://doi.org/10.1109/POWERAFRICA.2016.7556600","url":null,"abstract":"This paper presents a research and education based platform of simple Microgrid (MG) and Hardware-In-Loop (HIL) modern PC based Real Time Digital Simulator (RTDS) to simulate the MG platform set up. The value of simulator is evaluated using different functions for performance analysis of MG test bed under different simulation environment. The Simulink software is use to build the detailed model of MG and controller which can be used to solve the voltage/VAr and frequency control problems offline. The issues of MG control as a single agent or value of multi-agent decision support are discussed. The performance of controls is simulated online using the OPAL RT and eMAGAsim for economic selection and effectiveness of the controls, which will be sufficient for enhancing the design and capacity of MG for meeting its reliable and efficient power supply objectives under different contingencies. The developed test bed capability has been demonstrated by using it for validating different controls system for securing the MG network under different contingencies.","PeriodicalId":177444,"journal":{"name":"2016 IEEE PES PowerAfrica","volume":"200 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124280807","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-06-01DOI: 10.1109/POWERAFRICA.2016.7556613
Maureen Murage, M. Gabriela Martinez, C. Lindsay Anderson
Day-ahead power commitment of a wind farm is difficult to precisely determine due to wind's non-dispatachable nature. The coupling of a wind farm with a storage unit favors controllability of the combined output and allows for improved look ahead commitment. For the power system, advance commitment enhances scheduling, especially at high wind penetration levels. This is particularly important in the case of Kenya where wind power production is expected to increase to 10% of total projected installed capacity. To address this need for improved look-ahead commitment, this paper develops a two-stage stochastic model to determine optimal day-ahead power commitment and intra-day operation of the combined Lake Turkana Wind Power project with available storage, taking into account the unique structure of the Kenyan power market.
{"title":"A stochastic approach to the optimal management of a Kenyan wind farm coupled with storage","authors":"Maureen Murage, M. Gabriela Martinez, C. Lindsay Anderson","doi":"10.1109/POWERAFRICA.2016.7556613","DOIUrl":"https://doi.org/10.1109/POWERAFRICA.2016.7556613","url":null,"abstract":"Day-ahead power commitment of a wind farm is difficult to precisely determine due to wind's non-dispatachable nature. The coupling of a wind farm with a storage unit favors controllability of the combined output and allows for improved look ahead commitment. For the power system, advance commitment enhances scheduling, especially at high wind penetration levels. This is particularly important in the case of Kenya where wind power production is expected to increase to 10% of total projected installed capacity. To address this need for improved look-ahead commitment, this paper develops a two-stage stochastic model to determine optimal day-ahead power commitment and intra-day operation of the combined Lake Turkana Wind Power project with available storage, taking into account the unique structure of the Kenyan power market.","PeriodicalId":177444,"journal":{"name":"2016 IEEE PES PowerAfrica","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116287744","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-06-01DOI: 10.1109/POWERAFRICA.2016.7556564
A. Melodi, M. R. Adu
This research focused on obtaining model usable values of energy losses in Nigerian 11 kV township power distribution network. With more data available on other township feeders of the same network, an initial assessment of non-technical losses (NTL) and technical losses (TL) was reviewed to obtain improved model values. Proposed assessment algorithms were reapplied to obtain the NTL and TL models. The results show that NTL and TL for 11kV network are mostly 10 to 40% and 6 to 15% of the injected power respectively, and can power more than one community if saved. Averagely, voltage deviation (VD) profile, a factor of TLs, had a wider range from +3.3% down to -85.5% after 50 test computations. VDs at most load points are critical, contributing to more significant losses in networks downstream for the feeders. Considering these obtained losses assessments, it was concluded that NTL is very significant and can reach a maximum of approximately 40%, which is more than half of the most likely maximum value of TL in the studied feeders These model values are indications of more monetary implication of system losses, and cost of consuming energy despite poor service in the study location, Nigeria.
{"title":"A review of prevailing model energy loss values in typical 11 kV township distribution system of Nigerian electricity sector","authors":"A. Melodi, M. R. Adu","doi":"10.1109/POWERAFRICA.2016.7556564","DOIUrl":"https://doi.org/10.1109/POWERAFRICA.2016.7556564","url":null,"abstract":"This research focused on obtaining model usable values of energy losses in Nigerian 11 kV township power distribution network. With more data available on other township feeders of the same network, an initial assessment of non-technical losses (NTL) and technical losses (TL) was reviewed to obtain improved model values. Proposed assessment algorithms were reapplied to obtain the NTL and TL models. The results show that NTL and TL for 11kV network are mostly 10 to 40% and 6 to 15% of the injected power respectively, and can power more than one community if saved. Averagely, voltage deviation (VD) profile, a factor of TLs, had a wider range from +3.3% down to -85.5% after 50 test computations. VDs at most load points are critical, contributing to more significant losses in networks downstream for the feeders. Considering these obtained losses assessments, it was concluded that NTL is very significant and can reach a maximum of approximately 40%, which is more than half of the most likely maximum value of TL in the studied feeders These model values are indications of more monetary implication of system losses, and cost of consuming energy despite poor service in the study location, Nigeria.","PeriodicalId":177444,"journal":{"name":"2016 IEEE PES PowerAfrica","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114606713","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-06-01DOI: 10.1109/POWERAFRICA.2016.7556617
S. Kibaara, S. Chowdhury
Global attention has always focused on pollution and depletion of fossil fuels associated with the conventional energy sources. The non-conventional energy/renewable energy technologies (RETs) have always been considered clean and environmental friendly. The slow deployment of RETs such as wind and solar is associated with some environmental impacts such as use of large tracts of land which would otherwise be used for other economic activities for revenue generation such as agriculture, archaeological sites, forests etc. The impacts of RETs are evaluated in terms of the area impacted and damaging effect caused on the impacted area effectively leading to the loss of revenue. The impacts are quantified in terms of the ecosystem available in the area which varies from one region to the other. The research in this paper unveils the externalities which are unplanned, unwanted or unanticipated during construction and running of RETS yet they are not accounted for in the determination of COE and other cost parameters in many economic modelling tools.
{"title":"Review of economic modelling for quantifying the environmental impacts of renewable energy sources","authors":"S. Kibaara, S. Chowdhury","doi":"10.1109/POWERAFRICA.2016.7556617","DOIUrl":"https://doi.org/10.1109/POWERAFRICA.2016.7556617","url":null,"abstract":"Global attention has always focused on pollution and depletion of fossil fuels associated with the conventional energy sources. The non-conventional energy/renewable energy technologies (RETs) have always been considered clean and environmental friendly. The slow deployment of RETs such as wind and solar is associated with some environmental impacts such as use of large tracts of land which would otherwise be used for other economic activities for revenue generation such as agriculture, archaeological sites, forests etc. The impacts of RETs are evaluated in terms of the area impacted and damaging effect caused on the impacted area effectively leading to the loss of revenue. The impacts are quantified in terms of the ecosystem available in the area which varies from one region to the other. The research in this paper unveils the externalities which are unplanned, unwanted or unanticipated during construction and running of RETS yet they are not accounted for in the determination of COE and other cost parameters in many economic modelling tools.","PeriodicalId":177444,"journal":{"name":"2016 IEEE PES PowerAfrica","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121159396","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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