There are many patients in the blood purification center who need maintenance hemodialysis to maintain life. Those patients generally havelow resistance and are easily exposed to coronavirus because they go back and f...There are many patients in the blood purification center who need maintenance hemodialysis to maintain life. Those patients generally havelow resistance and are easily exposed to coronavirus because they go back and forth the hospital and residence three times a week andclosely contact with family, caregivers, community personnel, people in various means of transportation, medical staff, and other patientsvisiting hospital. Therefore, the blood purification center has become a high‑risk environment for the spread of COVID-19 infection. In viewof this, our center quickly responded to the formulation and implementation of infection prevention and control measures suitable for thecharacteristics of the blood purification center and continuous renal replacement therapy (CRRT) emergency plan for fever and suspectedpatients. According to these measures, we have a positive effect on preventing and controlling nosocomial infection in the blood purificationcenter.展开更多
Ductal carcinoma in situ (DCIS) is a non-invasive malignancy confined within</span></span><span><span><span style="font-family:""><span style="font-family:Verdana;&...Ductal carcinoma in situ (DCIS) is a non-invasive malignancy confined within</span></span><span><span><span style="font-family:""><span style="font-family:Verdana;"> the basement membrane of the breast ductal system. There is a lot of disparity in the natural history of DCIS with an estimated incidence of progression to </span><span style="font-family:Verdana;">invasive ductal carcinoma between 20%</span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> to</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> 53% over ten or more years afte</span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">r </span><span style="font-family:Verdana;">initial diagnosis. The surgical and adjuvant management of DCIS has advanced significantly in the last couple of decades. Nonetheless, surgeons, medical oncologist</span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">s</span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">, and radiation oncologists, along with their patients, still depend on conve</span><span style="font-family:Verdana;">ntional clinical and pathologic risk factors to make management decisions. Irrespective of the management strategy, long-term survival is excel</span><span style="font-family:Verdana;">lent. The debate around DCIS relates to preventing either under-treatment or over-treatment. In this paper, we will review the incidence and management </span><span style="font-family:Verdana;">options of DCIS. Additionally, we will focus on several current disputes related</span><span style="font-family:Verdana;"> to the management of DCIS, including breast conserving surgery, the role of radiation in breast conservation surgery, sentinel node biopsy in DCIS, hormonal therapy, various risk stratification schemes, and the option of active surveillance for low-risk DCIS.展开更多
Engineers often need to look for the right pieces of information by sifting through long engineering documents, It is a very tiring and time-consuming job. To address this issue, researchers are increasingly devoting ...Engineers often need to look for the right pieces of information by sifting through long engineering documents, It is a very tiring and time-consuming job. To address this issue, researchers are increasingly devoting their attention to new ways to help information users, including engineers, to access and retrieve document content. The research reported in this paper explores how to use the key technologies of document decomposition （study of document structure）, document mark-up （with EXtensible Mark- up Language （XML）, HyperText Mark-up Language （HTML）, and Scalable Vector Graphics （SVG））, and a facetted classification mechanism. Document content extraction is implemented via computer programming （with Java）. An Engineering Document Content Management System （EDCMS） developed in this research demonstrates that as information providers we can make document content in a more accessible manner for information users including engineers.The main features of the EDCMS system are： 1） EDCMS is a system that enables users, especially engineers, to access and retrieve information at content rather than document level. In other words, it provides the right pieces of information that answer specific questions so that engineers don＇t need to waste time sifting through the whole document to obtain the required piece of information. 2） Users can use the EDCMS via both the data and metadata of a document to access engineering document content. 3） Users can use the EDCMS to access and retrieve content objects, i.e. text, images and graphics （including engineering drawings） via multiple views and at different granularities based on decomposition schemes. Experiments with the EDCMS have been conducted on semi-structured documents, a textbook of CADCAM, and a set of project posters in the Engineering Design domain. Experimental results show that the system provides information users with a powerful solution to access document content.展开更多
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
Following the reform of the governance of irrigation schemes in Niger, producer cooperatives are encountering real difficulties in ensuring effective and efficient management of irrigation water, infrastructure mainte...Following the reform of the governance of irrigation schemes in Niger, producer cooperatives are encountering real difficulties in ensuring effective and efficient management of irrigation water, infrastructure maintenance and renewal of hydromechanical equipment. The objective of this research is to analyze the issues and challenges of capacity building for Konni producers in the context of AHA management reform in Niger. The methodological approach adopted is based on documentary research and field surveys with all the actors directly concerned with the management of the Konni irrigated perimeter. A total of 448 people were interviewed in all the localities selected. Direct observation and interview are the two field data collection techniques adopted. The data collected was processed and on the basis of the established diagnosis, the training needs were identified. The results show that there are several experiences in terms of training and capacity building of actors in charge of the management of irrigation systems at the Konni AHA level. However, the sustainability of the perimeter is threatened by various crises. The main themes that founded the first training were related to the mobilization, transport and distribution of irrigation water, operation and maintenance, and setting and collection of the fee. In view of the expectations of operators, future issues and challenges, the training modules are increasingly oriented towards social management, the integration of gender in management and environmental impacts. Even if technical progress is possible, the real lever is organizational and requires the professionalization of irrigators. This process requires a new pedagogical approach aimed at irrigators.展开更多
On the Pacific coast of Russia implementation of the methodology of the integrated nature management has a number of peculiarities. On the one hand, these districts are characterized by severe hydrometeorological cond...On the Pacific coast of Russia implementation of the methodology of the integrated nature management has a number of peculiarities. On the one hand, these districts are characterized by severe hydrometeorological conditions. On the other hand, Russia has no applicable legislation on coastal issues. Thus, to prepare informational, theoretical and methodical bases for organization of sustained nature management in coastal zones of the Russian Federation, we developed hierarchy structure of delimitation of coastal areas and recommendations for their development on the basis of nature resource and social-economic zoning. Zoning of the Russian Far East is suggested to include two major directions： （1） planning of sustainable development of the region and （2） solving contradictions between fisheries and productions of oil and gas in the coastal zones.展开更多
Based on a questionnaire survey, the aim of this paper is to explore the relationship of business process management （BPM） with managerial accounting system （MAS） and their economic performance consequences in Chi...Based on a questionnaire survey, the aim of this paper is to explore the relationship of business process management （BPM） with managerial accounting system （MAS） and their economic performance consequences in Chinese firms. Statistical data show that more firms accept business process improvement （BPI） other than business process reengineering （BPR） and optimize their activity chains other than supply chains. Through the construction of three elements, i.e., goal-setting, monitoring, and incentive schemes, of MAS, the study finds that when implementing BPM, firms usually use accounting indexes to set goals of the effect of business processes and combine the goals with monitoring and incentive schemes. Statistical data also show that incentive schemes get the lowest usage degree compared with goal-setting and monitoring. In addition, there are differences in their managerial accounting usages for BPM among firms considering ownership, industry, and scale. The main finding of this paper is that BPM empirically brings favorable changes to firms＇ economic performance via managerial accounting in general, and via goal-setting, monitoring, and incentive schemes in particular.展开更多
Due to global warming, extreme weather and climate events are becoming more frequent, highlighting the need to explore the changing characteristics of precipitation in China, including extreme precipitation. A cluster...Due to global warming, extreme weather and climate events are becoming more frequent, highlighting the need to explore the changing characteristics of precipitation in China, including extreme precipitation. A clustering algorithm was developed to classify summer(June, July, and August) daily precipitation in China from 1961 to 2020, considering spatial distribution, standard deviations, and frequency of extreme precipitation events. The results reveal six distinct precipitation climate zones, a classification that differs from previous divisions. While overall precipitation has decreased in most regions, the frequency of extreme precipitation events has increased across all clusters, indicating a shift in precipitation distribution patterns. Analysis shows that the weakened Lake Baikal blocking high and strengthened Mongolian cyclone influence the arid region in northwest China(Cluster 1), which is characterized by the lowest precipitation.The transition zone between the monsoon and arid region(Cluster 2) is affected by the Mongolian cyclone, water vapor transport from the Indian Ocean, and shifts in the monsoon boundary. Clusters 3 and 4 represent areas associated with advancement and retreat of the summer monsoon. In the Meiyu region, two distinct subregions have been identified exist.Cluster 4 is primarily influenced by the East Asia-Pacific wave train. Despite sharing similar climate drivers and proximity,Clusters 4 and 5 differ significantly due to topographic variations and disparate levels of urbanization. Cluster 5 exhibits a higher average precipitation, greater variability, and more frequent extreme events. Cluster 6 exhibits the highest overall precipitation in the coastal areas of Guangdong and Guangxi, where abundant water vapor contributes to a higher frequency of extreme precipitation. In addition, anthropogenic activities and urbanization significantly influence precipitation in Beijing-Tianjin-Hebei and Yangtze River Delta regions. This research proposes a precipitation classification scheme integrating multiple precipitation parameters, providing support for risk management and mitigation strategies in the face of increasing extreme precipitation events.展开更多
Guanting Reservoir, one of the drinking water supply sources of Beijing, suffers from water eutrophication. It is mainly supplied by Guishui River. Thus, to investigate the reasons of phosphorus （P） loss and improve...Guanting Reservoir, one of the drinking water supply sources of Beijing, suffers from water eutrophication. It is mainly supplied by Guishui River. Thus, to investigate the reasons of phosphorus （P） loss and improve the P management strategies in Guishui River watershed are important for the safety of drinking water in this region. In this study, a Revised Field P Ranking Scheme （PRS） was developed to reflect the field vulnerability of P loss at the field scale based on the Field PRS. In this new scheme, six factors are included, and each one was assigned a relative weight and a determination method. The affecting factors were classified into transport factors and source factors, and, the standards of environmental quality on surface water and soil erosion classification and degradation of the China were used in this scheme. By the new scheme, thirty-four fields in the Guishui River were categorized as ＂low＂, ＂medium＂ or ＂high＂ potential for P loss into the runoff. The results showed that the P loss risks of orchard and vegetable fields were higher than that of corn and soybean fields. The source factors were the main factors to affect P loss from the study area. In the study area, controlling P input and improving P usage efficiency are critical to decrease P loss. Based on the results, it was suggested that more attention should be paid on the fields of vegetable and orchard since they have extremely high usage rate of P and high soil test of P. Compared with P surplus by field measurements, the Revised Field PRS was more suitable for reflecting the characteristics of fields, and had higher potential capacity to identify critical source areas of P loss than PRS.展开更多
Resource sharing among peers is one of important application in Peer-to-Peer（P2P） network. Inexistenee of server makes P2P network to be a less trustable tool for property owners to distribute their resource. In ord...Resource sharing among peers is one of important application in Peer-to-Peer（P2P） network. Inexistenee of server makes P2P network to be a less trustable tool for property owners to distribute their resource. In order to protect intelligent property, reputation management strategy is adopted in many P2P network. As long as a P2P network reputation strategy is confirmed, application designer can employ a special detailed distribution scheme to fulfill content distribution within the net. Shmir （k, n） threshold scheme, for example, is an encryption scheme to enhance the distribution se curity of this kind of design. （k＊, n） threshold scheme is a new tool similar to Shmir scheme is proposed in this paper. The new scheme based on polynomial expansion and its security is decided by the one way function used in the secret distribution procedure. The scheme efficiency and its features as well as comparison between new and Shmir scheme are also discussed in this paper.展开更多
The objective of this research is to study the hydraulic performance of the water management system of the Telang 2 tidal lowland reclamation scheme with respect to the operation and maintenance of the system. The hyd...The objective of this research is to study the hydraulic performance of the water management system of the Telang 2 tidal lowland reclamation scheme with respect to the operation and maintenance of the system. The hydraulic performance of the system should inline with the food crop water requirement and its cropping pattern. Based on the result of this research, a basic model will be set up in order to support a sustainable agricultural development in the area. The methodology of this research consists of 1) Analysing the hydraulic performance of the water management system for the existing condition as well as under the proposed scenarios;2) socio-economical approach to the related farmers in relation to the operation and maintenance of the water management system;3) Mathematical modelling of crop water requirement and an optimal water management system and its water management zoning system;4) Cost benefit analysis related to operation and maintenance of the water management system, role sharing and cost sharing. In this study, computer softwares CROPWAT, DUFLOW dan ArcGIS have been used as supporting tools in the analysis and evaluation. CROPWAT model was used for calculating the crop water requirement based on the climatological condition and proposed cropping pattern (rice-maize and rice-rice) and its calendar. Based on the result of the CROPWAT model, DUFLOW model was used in order to evaluate the capacity and hydraulic performance of the open canal system. Finally based on the field water layer condition, water management zoning can be derived by using ArcGIS in relation to the crop water requirement and required water levels in the water management system. Based on this research, it can be concluded that the cropping pattern rice-rice or rice-maize are preferable and the co sharing is 50% by the Government and 50% by the farmers is the best option and this is also inline with the hydro-topographical condition of the related area.展开更多
Based on the proportionally fair scheme that Kelly proposed to solve the optimization problems for utility function in networks, and in order to improve the congestion control performance for the queue in router, the ...Based on the proportionally fair scheme that Kelly proposed to solve the optimization problems for utility function in networks, and in order to improve the congestion control performance for the queue in router, the linear and terminal sliding active queue management (AQM) algorithms are designed. Especially in the ter-minal sliding AQM algorithm, a special nonlinear terminal sliding surface is designed in order to force queue length to reach the desired value in finite time. The upper bound of the time is also obtained. Simulation re-sults demonstrate that the proposed congestion algorithm enables the system be better transient and stable performance. At the same time, the robustness is guaranteed.展开更多
船联网(internet of vehicle,IoS)是船舶信息交换的载体.基于区块链技术,在IoS上构建一种可信的信息交换机制,并提出相应的航行事件置信度计算与船舶信誉管理方案.该方案借鉴信息过滤的思想得到船舶综合相似度,利用加权熵值反向计算融...船联网(internet of vehicle,IoS)是船舶信息交换的载体.基于区块链技术,在IoS上构建一种可信的信息交换机制,并提出相应的航行事件置信度计算与船舶信誉管理方案.该方案借鉴信息过滤的思想得到船舶综合相似度,利用加权熵值反向计算融合的评级,根据回应船舶评级偏离融合评级的程度更新回应船舶的信誉值;然后采用最小二乘法建立信誉值倒数与评级误差之间的拟合关系,从而得以更新报告船舶的信誉值;进一步设计基于船舶信誉值的DPoS(delegated proof of stake)共识机制,旨在优先选择信誉值较高的船舶作为见证者船舶,以保障系统出块环境的稳定性和高效性.结果显示,在船舶滥用行为占比为40%的情况下,航行事件真实性判定的准确率仍在75%以上.研究表明,所提出的方案不仅有效提高了航行事件真实性判定的准确率,还能识别恶意船舶并限制其滥用行为,从而保证IoS环境的安全和稳定.展开更多
文摘There are many patients in the blood purification center who need maintenance hemodialysis to maintain life. Those patients generally havelow resistance and are easily exposed to coronavirus because they go back and forth the hospital and residence three times a week andclosely contact with family, caregivers, community personnel, people in various means of transportation, medical staff, and other patientsvisiting hospital. Therefore, the blood purification center has become a high‑risk environment for the spread of COVID-19 infection. In viewof this, our center quickly responded to the formulation and implementation of infection prevention and control measures suitable for thecharacteristics of the blood purification center and continuous renal replacement therapy (CRRT) emergency plan for fever and suspectedpatients. According to these measures, we have a positive effect on preventing and controlling nosocomial infection in the blood purificationcenter.
文摘Ductal carcinoma in situ (DCIS) is a non-invasive malignancy confined within</span></span><span><span><span style="font-family:""><span style="font-family:Verdana;"> the basement membrane of the breast ductal system. There is a lot of disparity in the natural history of DCIS with an estimated incidence of progression to </span><span style="font-family:Verdana;">invasive ductal carcinoma between 20%</span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> to</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> 53% over ten or more years afte</span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">r </span><span style="font-family:Verdana;">initial diagnosis. The surgical and adjuvant management of DCIS has advanced significantly in the last couple of decades. Nonetheless, surgeons, medical oncologist</span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">s</span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">, and radiation oncologists, along with their patients, still depend on conve</span><span style="font-family:Verdana;">ntional clinical and pathologic risk factors to make management decisions. Irrespective of the management strategy, long-term survival is excel</span><span style="font-family:Verdana;">lent. The debate around DCIS relates to preventing either under-treatment or over-treatment. In this paper, we will review the incidence and management </span><span style="font-family:Verdana;">options of DCIS. Additionally, we will focus on several current disputes related</span><span style="font-family:Verdana;"> to the management of DCIS, including breast conserving surgery, the role of radiation in breast conservation surgery, sentinel node biopsy in DCIS, hormonal therapy, various risk stratification schemes, and the option of active surveillance for low-risk DCIS.
基金This work was supported by the UK Engineering and Physical Sciences Research Council(EPSRC)(No.GR/R67507/01).
文摘Engineers often need to look for the right pieces of information by sifting through long engineering documents, It is a very tiring and time-consuming job. To address this issue, researchers are increasingly devoting their attention to new ways to help information users, including engineers, to access and retrieve document content. The research reported in this paper explores how to use the key technologies of document decomposition （study of document structure）, document mark-up （with EXtensible Mark- up Language （XML）, HyperText Mark-up Language （HTML）, and Scalable Vector Graphics （SVG））, and a facetted classification mechanism. Document content extraction is implemented via computer programming （with Java）. An Engineering Document Content Management System （EDCMS） developed in this research demonstrates that as information providers we can make document content in a more accessible manner for information users including engineers.The main features of the EDCMS system are： 1） EDCMS is a system that enables users, especially engineers, to access and retrieve information at content rather than document level. In other words, it provides the right pieces of information that answer specific questions so that engineers don＇t need to waste time sifting through the whole document to obtain the required piece of information. 2） Users can use the EDCMS via both the data and metadata of a document to access engineering document content. 3） Users can use the EDCMS to access and retrieve content objects, i.e. text, images and graphics （including engineering drawings） via multiple views and at different granularities based on decomposition schemes. Experiments with the EDCMS have been conducted on semi-structured documents, a textbook of CADCAM, and a set of project posters in the Engineering Design domain. Experimental results show that the system provides information users with a powerful solution to access document content.
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Following the reform of the governance of irrigation schemes in Niger, producer cooperatives are encountering real difficulties in ensuring effective and efficient management of irrigation water, infrastructure maintenance and renewal of hydromechanical equipment. The objective of this research is to analyze the issues and challenges of capacity building for Konni producers in the context of AHA management reform in Niger. The methodological approach adopted is based on documentary research and field surveys with all the actors directly concerned with the management of the Konni irrigated perimeter. A total of 448 people were interviewed in all the localities selected. Direct observation and interview are the two field data collection techniques adopted. The data collected was processed and on the basis of the established diagnosis, the training needs were identified. The results show that there are several experiences in terms of training and capacity building of actors in charge of the management of irrigation systems at the Konni AHA level. However, the sustainability of the perimeter is threatened by various crises. The main themes that founded the first training were related to the mobilization, transport and distribution of irrigation water, operation and maintenance, and setting and collection of the fee. In view of the expectations of operators, future issues and challenges, the training modules are increasingly oriented towards social management, the integration of gender in management and environmental impacts. Even if technical progress is possible, the real lever is organizational and requires the professionalization of irrigators. This process requires a new pedagogical approach aimed at irrigators.
文摘On the Pacific coast of Russia implementation of the methodology of the integrated nature management has a number of peculiarities. On the one hand, these districts are characterized by severe hydrometeorological conditions. On the other hand, Russia has no applicable legislation on coastal issues. Thus, to prepare informational, theoretical and methodical bases for organization of sustained nature management in coastal zones of the Russian Federation, we developed hierarchy structure of delimitation of coastal areas and recommendations for their development on the basis of nature resource and social-economic zoning. Zoning of the Russian Far East is suggested to include two major directions： （1） planning of sustainable development of the region and （2） solving contradictions between fisheries and productions of oil and gas in the coastal zones.
文摘Based on a questionnaire survey, the aim of this paper is to explore the relationship of business process management （BPM） with managerial accounting system （MAS） and their economic performance consequences in Chinese firms. Statistical data show that more firms accept business process improvement （BPI） other than business process reengineering （BPR） and optimize their activity chains other than supply chains. Through the construction of three elements, i.e., goal-setting, monitoring, and incentive schemes, of MAS, the study finds that when implementing BPM, firms usually use accounting indexes to set goals of the effect of business processes and combine the goals with monitoring and incentive schemes. Statistical data also show that incentive schemes get the lowest usage degree compared with goal-setting and monitoring. In addition, there are differences in their managerial accounting usages for BPM among firms considering ownership, industry, and scale. The main finding of this paper is that BPM empirically brings favorable changes to firms＇ economic performance via managerial accounting in general, and via goal-setting, monitoring, and incentive schemes in particular.
基金National Natural Science Foundation of China(U2442202, 42274217, 62441501)Key Innovation Team of China Meteorological Administration (CMA2024ZD01)Scientific Research Foundation of CUIT (376278, KYTZ202158)。
文摘Due to global warming, extreme weather and climate events are becoming more frequent, highlighting the need to explore the changing characteristics of precipitation in China, including extreme precipitation. A clustering algorithm was developed to classify summer(June, July, and August) daily precipitation in China from 1961 to 2020, considering spatial distribution, standard deviations, and frequency of extreme precipitation events. The results reveal six distinct precipitation climate zones, a classification that differs from previous divisions. While overall precipitation has decreased in most regions, the frequency of extreme precipitation events has increased across all clusters, indicating a shift in precipitation distribution patterns. Analysis shows that the weakened Lake Baikal blocking high and strengthened Mongolian cyclone influence the arid region in northwest China(Cluster 1), which is characterized by the lowest precipitation.The transition zone between the monsoon and arid region(Cluster 2) is affected by the Mongolian cyclone, water vapor transport from the Indian Ocean, and shifts in the monsoon boundary. Clusters 3 and 4 represent areas associated with advancement and retreat of the summer monsoon. In the Meiyu region, two distinct subregions have been identified exist.Cluster 4 is primarily influenced by the East Asia-Pacific wave train. Despite sharing similar climate drivers and proximity,Clusters 4 and 5 differ significantly due to topographic variations and disparate levels of urbanization. Cluster 5 exhibits a higher average precipitation, greater variability, and more frequent extreme events. Cluster 6 exhibits the highest overall precipitation in the coastal areas of Guangdong and Guangxi, where abundant water vapor contributes to a higher frequency of extreme precipitation. In addition, anthropogenic activities and urbanization significantly influence precipitation in Beijing-Tianjin-Hebei and Yangtze River Delta regions. This research proposes a precipitation classification scheme integrating multiple precipitation parameters, providing support for risk management and mitigation strategies in the face of increasing extreme precipitation events.
基金Project supported by the National Basic Research Program of China(No.2005CB121107)the Innovation Research Group of National Basic Research Program of China(No.2005).
文摘Guanting Reservoir, one of the drinking water supply sources of Beijing, suffers from water eutrophication. It is mainly supplied by Guishui River. Thus, to investigate the reasons of phosphorus （P） loss and improve the P management strategies in Guishui River watershed are important for the safety of drinking water in this region. In this study, a Revised Field P Ranking Scheme （PRS） was developed to reflect the field vulnerability of P loss at the field scale based on the Field PRS. In this new scheme, six factors are included, and each one was assigned a relative weight and a determination method. The affecting factors were classified into transport factors and source factors, and, the standards of environmental quality on surface water and soil erosion classification and degradation of the China were used in this scheme. By the new scheme, thirty-four fields in the Guishui River were categorized as ＂low＂, ＂medium＂ or ＂high＂ potential for P loss into the runoff. The results showed that the P loss risks of orchard and vegetable fields were higher than that of corn and soybean fields. The source factors were the main factors to affect P loss from the study area. In the study area, controlling P input and improving P usage efficiency are critical to decrease P loss. Based on the results, it was suggested that more attention should be paid on the fields of vegetable and orchard since they have extremely high usage rate of P and high soil test of P. Compared with P surplus by field measurements, the Revised Field PRS was more suitable for reflecting the characteristics of fields, and had higher potential capacity to identify critical source areas of P loss than PRS.
基金Supported by the National Natural Science Foun-dation of China (60473072)
文摘Resource sharing among peers is one of important application in Peer-to-Peer（P2P） network. Inexistenee of server makes P2P network to be a less trustable tool for property owners to distribute their resource. In order to protect intelligent property, reputation management strategy is adopted in many P2P network. As long as a P2P network reputation strategy is confirmed, application designer can employ a special detailed distribution scheme to fulfill content distribution within the net. Shmir （k, n） threshold scheme, for example, is an encryption scheme to enhance the distribution se curity of this kind of design. （k＊, n） threshold scheme is a new tool similar to Shmir scheme is proposed in this paper. The new scheme based on polynomial expansion and its security is decided by the one way function used in the secret distribution procedure. The scheme efficiency and its features as well as comparison between new and Shmir scheme are also discussed in this paper.
文摘A two-stage containment scheme is proposed to minimize spreading of the novel coronavirus. Two stages of quarantine each of 14 days will be involved.
文摘The objective of this research is to study the hydraulic performance of the water management system of the Telang 2 tidal lowland reclamation scheme with respect to the operation and maintenance of the system. The hydraulic performance of the system should inline with the food crop water requirement and its cropping pattern. Based on the result of this research, a basic model will be set up in order to support a sustainable agricultural development in the area. The methodology of this research consists of 1) Analysing the hydraulic performance of the water management system for the existing condition as well as under the proposed scenarios;2) socio-economical approach to the related farmers in relation to the operation and maintenance of the water management system;3) Mathematical modelling of crop water requirement and an optimal water management system and its water management zoning system;4) Cost benefit analysis related to operation and maintenance of the water management system, role sharing and cost sharing. In this study, computer softwares CROPWAT, DUFLOW dan ArcGIS have been used as supporting tools in the analysis and evaluation. CROPWAT model was used for calculating the crop water requirement based on the climatological condition and proposed cropping pattern (rice-maize and rice-rice) and its calendar. Based on the result of the CROPWAT model, DUFLOW model was used in order to evaluate the capacity and hydraulic performance of the open canal system. Finally based on the field water layer condition, water management zoning can be derived by using ArcGIS in relation to the crop water requirement and required water levels in the water management system. Based on this research, it can be concluded that the cropping pattern rice-rice or rice-maize are preferable and the co sharing is 50% by the Government and 50% by the farmers is the best option and this is also inline with the hydro-topographical condition of the related area.
文摘Based on the proportionally fair scheme that Kelly proposed to solve the optimization problems for utility function in networks, and in order to improve the congestion control performance for the queue in router, the linear and terminal sliding active queue management (AQM) algorithms are designed. Especially in the ter-minal sliding AQM algorithm, a special nonlinear terminal sliding surface is designed in order to force queue length to reach the desired value in finite time. The upper bound of the time is also obtained. Simulation re-sults demonstrate that the proposed congestion algorithm enables the system be better transient and stable performance. At the same time, the robustness is guaranteed.
文摘船联网(internet of vehicle,IoS)是船舶信息交换的载体.基于区块链技术,在IoS上构建一种可信的信息交换机制,并提出相应的航行事件置信度计算与船舶信誉管理方案.该方案借鉴信息过滤的思想得到船舶综合相似度,利用加权熵值反向计算融合的评级,根据回应船舶评级偏离融合评级的程度更新回应船舶的信誉值;然后采用最小二乘法建立信誉值倒数与评级误差之间的拟合关系,从而得以更新报告船舶的信誉值;进一步设计基于船舶信誉值的DPoS(delegated proof of stake)共识机制,旨在优先选择信誉值较高的船舶作为见证者船舶,以保障系统出块环境的稳定性和高效性.结果显示,在船舶滥用行为占比为40%的情况下,航行事件真实性判定的准确率仍在75%以上.研究表明,所提出的方案不仅有效提高了航行事件真实性判定的准确率,还能识别恶意船舶并限制其滥用行为,从而保证IoS环境的安全和稳定.
