Ontology-based semantic information integration resolve the schema-level heterogeneity and part of data level heterogeneity between distributed data sources. But it is ubiquitous that schema semantics of information i...Ontology-based semantic information integration resolve the schema-level heterogeneity and part of data level heterogeneity between distributed data sources. But it is ubiquitous that schema semantics of information is identical while the interpretation of it varies with different context, and ontology-based semantic information integration can not resolve this context heterogeneity. By introducing context representation and context mediation to ontology based information integration, the attribute-level context heterogeneity can be detected and reconciled automatically, and hence a complete solution for semantic heterogeneity is formed. Through a concrete example, the context representation and the process in which the attribute-level context heterogeneity is reconciled during query processing are presented. This resolution can make up the deficiency of schema mapping based semantic information integration. With the architecture proposed in this paper the semantic heterogeneity solution is adaptive and extensive.展开更多
In the upcoming 5 G heterogeneous networks, leveraging multiple radio access technologies(RATs) shows to be a crucial issue in achieving RAT multiplexing gain to meet the explosive traffic demand. For always best conn...In the upcoming 5 G heterogeneous networks, leveraging multiple radio access technologies(RATs) shows to be a crucial issue in achieving RAT multiplexing gain to meet the explosive traffic demand. For always best connection(ABC), users tend to activate parallel transmission across all available RATs. However from a system-wide perspective, this might not be optimal given the context of network load, interference and diverse service requirements. To intelligently determine how to use these multi-RAT access resources concurrently, this paper proposes a joint multi-RAT user association and resource allocation strategy with triple decision and integrated context awareness of users and networks. A dynamic game based ant colony algorithm(GACA) is designed to simultaneously maximize the system utility and the fairness of resource allocation. Simulation results show that it's more reasonable to make multi-RAT association decision from a system-wide viewpoint than from an individual one. Compared to max-SNR based and ABC based strategies, the proposed method alleviates network congestion and optimizes resource allocation. It obtains 39%~70% performance improvement.展开更多
Heterogeneous urban development of Iran during current decades along with ineffectiveness of urban planning system and shortcoming of national development programs and land use planning have led to many problems of ur...Heterogeneous urban development of Iran during current decades along with ineffectiveness of urban planning system and shortcoming of national development programs and land use planning have led to many problems of urbanism in Iran so that heterogeneous and old contexts can be named as one of the problems in this field. Urban decay is one of the serious and inevitable problems of urban management in all countries. This study has been conducted to analyze and assess the effect of regional factors on development of problematic urban contexts emphasizing on socio- economic indicators in Bandar Abbas City. Having urban macro-indicators at regional and country level, Bandar Abbas City faces various physical problems which problematic and old contexts are the most important of them that cover an area of 1033 hectares. Economic issues and heterogeneity within social contexts have expanded the mentioned problem in addition to physical problems. Methodology of this study has been analytical-descriptive, data collection method of documentary information has been gathered from relevant administrative organization such as Statistical Center of Iran, the Municipality and the Ministry of Housing and Urban Development, and survey data has been collected through 90 questionnaires. According to the obtained results of this study, it could be found that social, economic, political and managerial factors have had effects on formation of heterogeneous contexts and extensive migration during the current years has expanded problematic contexts of Bandar Abbas due to its specific regional conditions. Moreover, the obtained results of this study indicated that heterogeneous contexts had some features including fine-grained, inadequate access network, impervious, inferior materials and poor construction of buildings and lack of necessary infrastructure.展开更多
The study of the international literary relations in comparative literature includes not only the positivistic relations of different nations and different literary systems, but also the relations of variation among d...The study of the international literary relations in comparative literature includes not only the positivistic relations of different nations and different literary systems, but also the relations of variation among different literatures when it comes to the cross-civilization heterogeneity. Therefore, the positivistic approach and that of variation in the study of international literary relations constitute the two indispensable pillars in this field.展开更多
Real-time video data transmission is currently emerging as a popular application among mobile users but it is very sensitive to QoS degradation due to packet losses in wireless networks.In order to achieve service con...Real-time video data transmission is currently emerging as a popular application among mobile users but it is very sensitive to QoS degradation due to packet losses in wireless networks.In order to achieve service continuity and integrity upon handoffs among heterogeneous networks,provisioning of seamless and secure mobility is required.However,in order to reduce the delay and packet losses during vertical handovers we need to employ supportive protocols like context transfer.In this paper we evaluate the QoS of video transmission over a heterogeneous 3G-WLAN network.The aggregate video data traffic is represented by a dynamic two-dimensional Markov chain model,which has been evaluated against real video data measurement.Upon the vertical handover, appropriate AAA handshaking and enhanced mobility management using context transfer have been considered.Perceived QoS evaluation of video streams was performed based on peak signal-noise ratio(PSNR) measurements,while we analyticallyestimated the number of packet losses during handovers.The results show that both packet loss within the converged network and loss occurrence affecting the perceived video quality is reduced. Moreover,the proposed context transfer scheme minimizes handover delay and the number of lost packet up to 3 times compared to standard AAA handshaking.展开更多
基金The National Natural Science Foundation of China (No.50305007)the Scientific Research Project of Hubei Provincial Department of Education (No.D200618003)
文摘Ontology-based semantic information integration resolve the schema-level heterogeneity and part of data level heterogeneity between distributed data sources. But it is ubiquitous that schema semantics of information is identical while the interpretation of it varies with different context, and ontology-based semantic information integration can not resolve this context heterogeneity. By introducing context representation and context mediation to ontology based information integration, the attribute-level context heterogeneity can be detected and reconciled automatically, and hence a complete solution for semantic heterogeneity is formed. Through a concrete example, the context representation and the process in which the attribute-level context heterogeneity is reconciled during query processing are presented. This resolution can make up the deficiency of schema mapping based semantic information integration. With the architecture proposed in this paper the semantic heterogeneity solution is adaptive and extensive.
基金supported by the National Natural Science Fund of China(Grant NO.61771065,Grant NO.61571054 and Grant NO.61631005)Beijing Nova Program(NO.Z151100000315077)
文摘In the upcoming 5 G heterogeneous networks, leveraging multiple radio access technologies(RATs) shows to be a crucial issue in achieving RAT multiplexing gain to meet the explosive traffic demand. For always best connection(ABC), users tend to activate parallel transmission across all available RATs. However from a system-wide perspective, this might not be optimal given the context of network load, interference and diverse service requirements. To intelligently determine how to use these multi-RAT access resources concurrently, this paper proposes a joint multi-RAT user association and resource allocation strategy with triple decision and integrated context awareness of users and networks. A dynamic game based ant colony algorithm(GACA) is designed to simultaneously maximize the system utility and the fairness of resource allocation. Simulation results show that it's more reasonable to make multi-RAT association decision from a system-wide viewpoint than from an individual one. Compared to max-SNR based and ABC based strategies, the proposed method alleviates network congestion and optimizes resource allocation. It obtains 39%~70% performance improvement.
文摘Heterogeneous urban development of Iran during current decades along with ineffectiveness of urban planning system and shortcoming of national development programs and land use planning have led to many problems of urbanism in Iran so that heterogeneous and old contexts can be named as one of the problems in this field. Urban decay is one of the serious and inevitable problems of urban management in all countries. This study has been conducted to analyze and assess the effect of regional factors on development of problematic urban contexts emphasizing on socio- economic indicators in Bandar Abbas City. Having urban macro-indicators at regional and country level, Bandar Abbas City faces various physical problems which problematic and old contexts are the most important of them that cover an area of 1033 hectares. Economic issues and heterogeneity within social contexts have expanded the mentioned problem in addition to physical problems. Methodology of this study has been analytical-descriptive, data collection method of documentary information has been gathered from relevant administrative organization such as Statistical Center of Iran, the Municipality and the Ministry of Housing and Urban Development, and survey data has been collected through 90 questionnaires. According to the obtained results of this study, it could be found that social, economic, political and managerial factors have had effects on formation of heterogeneous contexts and extensive migration during the current years has expanded problematic contexts of Bandar Abbas due to its specific regional conditions. Moreover, the obtained results of this study indicated that heterogeneous contexts had some features including fine-grained, inadequate access network, impervious, inferior materials and poor construction of buildings and lack of necessary infrastructure.
文摘The study of the international literary relations in comparative literature includes not only the positivistic relations of different nations and different literary systems, but also the relations of variation among different literatures when it comes to the cross-civilization heterogeneity. Therefore, the positivistic approach and that of variation in the study of international literary relations constitute the two indispensable pillars in this field.
基金financed by the Greek General Secretariat for Research and Technology(GSRT) grant PENED
文摘Real-time video data transmission is currently emerging as a popular application among mobile users but it is very sensitive to QoS degradation due to packet losses in wireless networks.In order to achieve service continuity and integrity upon handoffs among heterogeneous networks,provisioning of seamless and secure mobility is required.However,in order to reduce the delay and packet losses during vertical handovers we need to employ supportive protocols like context transfer.In this paper we evaluate the QoS of video transmission over a heterogeneous 3G-WLAN network.The aggregate video data traffic is represented by a dynamic two-dimensional Markov chain model,which has been evaluated against real video data measurement.Upon the vertical handover, appropriate AAA handshaking and enhanced mobility management using context transfer have been considered.Perceived QoS evaluation of video streams was performed based on peak signal-noise ratio(PSNR) measurements,while we analyticallyestimated the number of packet losses during handovers.The results show that both packet loss within the converged network and loss occurrence affecting the perceived video quality is reduced. Moreover,the proposed context transfer scheme minimizes handover delay and the number of lost packet up to 3 times compared to standard AAA handshaking.
