Pub Date : 2013-04-14DOI: 10.1109/INFCOM.2013.6566907
Xuan Liu, K. Ren, Yanling Yuan, Zuyi Li, Qian Wang
Power network is one of the most critical infrastructures in a nation and is always a target of attackers. Recently, many schemes are proposed to protect the security of power systems. However, most of existing works did not consider the component attacking cost and ignored the relationship between the budget deployed on the component and its attacking cost. To address this problem, in this paper we introduce the concept of budget-cost function, which describes the dynamic characteristics of component attacking cost, and propose a new model to protect power grid against intentional attacks. In our model, the attackers have limited attacking capacity and aim to maximize the damage of attacks. On the other hand, the defenders aim to find the optimal strategy of the budget deployment to limit the damage to an expected level. We formulate the above problem as a nonlinear optimization problem and solve it by employing the primal-dual interior-point method. To the author's best knowledge, this is the first work which analyzes the optimal budget deployment strategy based on budget-cost function. Simulations on the IEEE 5-bus system demonstrate the correctness and effectiveness of the proposed model and algorithms. The results provide a basis of budget investment for power systems.
{"title":"Optimal budget deployment strategy against power grid interdiction","authors":"Xuan Liu, K. Ren, Yanling Yuan, Zuyi Li, Qian Wang","doi":"10.1109/INFCOM.2013.6566907","DOIUrl":"https://doi.org/10.1109/INFCOM.2013.6566907","url":null,"abstract":"Power network is one of the most critical infrastructures in a nation and is always a target of attackers. Recently, many schemes are proposed to protect the security of power systems. However, most of existing works did not consider the component attacking cost and ignored the relationship between the budget deployed on the component and its attacking cost. To address this problem, in this paper we introduce the concept of budget-cost function, which describes the dynamic characteristics of component attacking cost, and propose a new model to protect power grid against intentional attacks. In our model, the attackers have limited attacking capacity and aim to maximize the damage of attacks. On the other hand, the defenders aim to find the optimal strategy of the budget deployment to limit the damage to an expected level. We formulate the above problem as a nonlinear optimization problem and solve it by employing the primal-dual interior-point method. To the author's best knowledge, this is the first work which analyzes the optimal budget deployment strategy based on budget-cost function. Simulations on the IEEE 5-bus system demonstrate the correctness and effectiveness of the proposed model and algorithms. The results provide a basis of budget investment for power systems.","PeriodicalId":206346,"journal":{"name":"2013 Proceedings IEEE INFOCOM","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123672920","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 : 2013-04-14DOI: 10.1109/INFCOM.2013.6566778
Shuai Wang, Guang Tan, Yunhuai Liu, Hongbo Jiang, T. He
Reducing transmission redundancy is key to the efficiency of wireless network broadcast. A standard technique to achieve this is to create a network backbone consisting of a subset of nodes that are responsible for data forwarding, while other nodes act as passive receivers. On top of this, network coding (NC) is often used to further reduce unnecessary transmissions. The main problem with this backbone+NC approach is that the backbone construction process is blind of what is needed by NC, thus may produce a structure with little benefit to the NC algorithms. To address this problem, we propose a Coding Opportunity Aware Backbone (COAB) construction scheme, which seeks to maximally exploit coding opportunities when selecting backbone forwarders. We show that the better informed backbone construction process leads to significantly increased coding frequency, at minimal cost of localized information exchange. The highlight of our work is COAB's broad applicability and effectiveness. We integrate COAB with ten state-of-the-art broadcast algorithms, specified in eight publications [1]-[8], and evaluate it with prototype implementations with 30 MICAz nodes. The experimental results show that our design outperforms the existing schemes substantially.
{"title":"Coding Opportunity Aware Backbone metrics for broadcast in wireless networks","authors":"Shuai Wang, Guang Tan, Yunhuai Liu, Hongbo Jiang, T. He","doi":"10.1109/INFCOM.2013.6566778","DOIUrl":"https://doi.org/10.1109/INFCOM.2013.6566778","url":null,"abstract":"Reducing transmission redundancy is key to the efficiency of wireless network broadcast. A standard technique to achieve this is to create a network backbone consisting of a subset of nodes that are responsible for data forwarding, while other nodes act as passive receivers. On top of this, network coding (NC) is often used to further reduce unnecessary transmissions. The main problem with this backbone+NC approach is that the backbone construction process is blind of what is needed by NC, thus may produce a structure with little benefit to the NC algorithms. To address this problem, we propose a Coding Opportunity Aware Backbone (COAB) construction scheme, which seeks to maximally exploit coding opportunities when selecting backbone forwarders. We show that the better informed backbone construction process leads to significantly increased coding frequency, at minimal cost of localized information exchange. The highlight of our work is COAB's broad applicability and effectiveness. We integrate COAB with ten state-of-the-art broadcast algorithms, specified in eight publications [1]-[8], and evaluate it with prototype implementations with 30 MICAz nodes. The experimental results show that our design outperforms the existing schemes substantially.","PeriodicalId":206346,"journal":{"name":"2013 Proceedings IEEE INFOCOM","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122070925","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 : 2013-04-14DOI: 10.1109/INFCOMW.2013.6562906
H. Georg, N. Dorsch, M. Putzke, C. Wietfeld
Driven by the increasing application of Smart Grid technologies in today's power systems, communication networks are becoming more and more important for exchanging monitoring, control and protection information on local and wide area level. For communication the IEC 61850 standard is a candidate for the Smart Grid and has been introduced for Substation Automation Systems (SAS) some years ago. IEC 61850 provides interoperability among various manufactures and enables systemwide communication between intelligent components of future power systems. However, as IEC 61850 addresses Ethernet (ISO/IEC 8802-3 family) as network technology, especially high performance aspects of Ethernet have become increasingly important for time-critical communication within substation automation systems. In this paper we introduce the generic architecture of IEC 61850 and present our modelling approach for evaluating high performance and real-time capability of communication technologies for future smart grid application. First, we give a short overview of the IEC 61850 protocol and present communication flows in substation automation systems according to the standard. Here we focus on substation automation at bay level, located inside an exemplary substation node taken from the IEEE 39-bus power system network. Afterwards we demonstrate our modeling approach for communication networks based on IEC 61850. For performance evaluation we developed a simulation model along with an analytical approach on basis of Network Calculus, enabling to identify worst case boundaries for intra-substation communication. Finally results for simulative and analytical modelling are provided and cross validated for two bay level scenarios, showing the applicability of Network Calculus for real-time constrained smart grid communication.
{"title":"Performance evaluation of time-critical communication networks for smart grids based on IEC 61850","authors":"H. Georg, N. Dorsch, M. Putzke, C. Wietfeld","doi":"10.1109/INFCOMW.2013.6562906","DOIUrl":"https://doi.org/10.1109/INFCOMW.2013.6562906","url":null,"abstract":"Driven by the increasing application of Smart Grid technologies in today's power systems, communication networks are becoming more and more important for exchanging monitoring, control and protection information on local and wide area level. For communication the IEC 61850 standard is a candidate for the Smart Grid and has been introduced for Substation Automation Systems (SAS) some years ago. IEC 61850 provides interoperability among various manufactures and enables systemwide communication between intelligent components of future power systems. However, as IEC 61850 addresses Ethernet (ISO/IEC 8802-3 family) as network technology, especially high performance aspects of Ethernet have become increasingly important for time-critical communication within substation automation systems. In this paper we introduce the generic architecture of IEC 61850 and present our modelling approach for evaluating high performance and real-time capability of communication technologies for future smart grid application. First, we give a short overview of the IEC 61850 protocol and present communication flows in substation automation systems according to the standard. Here we focus on substation automation at bay level, located inside an exemplary substation node taken from the IEEE 39-bus power system network. Afterwards we demonstrate our modeling approach for communication networks based on IEC 61850. For performance evaluation we developed a simulation model along with an analytical approach on basis of Network Calculus, enabling to identify worst case boundaries for intra-substation communication. Finally results for simulative and analytical modelling are provided and cross validated for two bay level scenarios, showing the applicability of Network Calculus for real-time constrained smart grid communication.","PeriodicalId":206346,"journal":{"name":"2013 Proceedings IEEE INFOCOM","volume":"221 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120860793","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 : 2013-04-14DOI: 10.1109/INFCOM.2013.6566908
Xiaowen Gong, Junshan Zhang, D. Cochran
Radar sensors, which actively transmit radio waves and collect RF energy scattered by objects in the environment, offer a number of advantages over purely passive sensors. An important issue in radar is that the transmitted energy may be scattered by objects that are not of interest as well as objects of interest (e.g., targets). The detection performance of radar systems is affected by such clutter as well as noise. Further, in many applications, clutter can be substantially stronger than the signals of interest. To combat the effect of clutter, a popular method is to take advantage of the Doppler frequency shift (DFS) extracted from the echo signal due to the relative motion of a target with respect to the radar. Unfortunately, a sensor coverage model that only depends on the distance to a target would fail to capture the DFS. In this paper, we set forth the concept of Doppler coverage for a network of spatially distributed radars. Specifically, a target is said to be Doppler-covered if, regardless of its direction of motion, there exists some radar in the network whose signalto-noise ratio (SNR) is sufficiently high and the DFS at that radar is sufficiently large. Based on the Doppler coverage model, we first propose an efficient method to characterize Dopplercovered regions for arbitrarily deployed radars. Then we design an algorithm for deriving the minimum radar density required to achieve Doppler coverage in a region under any polygonal deployment pattern, and further apply it to investigate the regular triangle based deployment.
{"title":"When target motion matters: Doppler coverage in radar sensor networks","authors":"Xiaowen Gong, Junshan Zhang, D. Cochran","doi":"10.1109/INFCOM.2013.6566908","DOIUrl":"https://doi.org/10.1109/INFCOM.2013.6566908","url":null,"abstract":"Radar sensors, which actively transmit radio waves and collect RF energy scattered by objects in the environment, offer a number of advantages over purely passive sensors. An important issue in radar is that the transmitted energy may be scattered by objects that are not of interest as well as objects of interest (e.g., targets). The detection performance of radar systems is affected by such clutter as well as noise. Further, in many applications, clutter can be substantially stronger than the signals of interest. To combat the effect of clutter, a popular method is to take advantage of the Doppler frequency shift (DFS) extracted from the echo signal due to the relative motion of a target with respect to the radar. Unfortunately, a sensor coverage model that only depends on the distance to a target would fail to capture the DFS. In this paper, we set forth the concept of Doppler coverage for a network of spatially distributed radars. Specifically, a target is said to be Doppler-covered if, regardless of its direction of motion, there exists some radar in the network whose signalto-noise ratio (SNR) is sufficiently high and the DFS at that radar is sufficiently large. Based on the Doppler coverage model, we first propose an efficient method to characterize Dopplercovered regions for arbitrarily deployed radars. Then we design an algorithm for deriving the minimum radar density required to achieve Doppler coverage in a region under any polygonal deployment pattern, and further apply it to investigate the regular triangle based deployment.","PeriodicalId":206346,"journal":{"name":"2013 Proceedings IEEE INFOCOM","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125952002","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 : 2013-04-14DOI: 10.1109/INFCOM.2013.6566836
Chien-Han Chai, Yuan-Yao Shih, Ai-Chun Pang
With the explosive growth of mobile data traffic, the femtocell technology is one of the proper solutions to enhance mobile service quality and system capacity for cellular networks. However, one of the key problems for femtocell deployment is to find appropriate access control in which mobile operators and users are willing to be involved. Among all kinds of access control modes, the hybrid access mode is considered as the most promising one, which allows femtocells to provide preferential access to femtocell owners and subscribers while other public users can access femtocells with certain restriction. Since all femtocell owners are selfish, how to provide enough incentives to the owners for sharing their femtocell resources is challenging. In this paper, we construct an economic framework for mobile operator and femtocell users by a game theoretical analysis and introduce the concept of profit sharing to provide a positive cycle to sustain the femtocell service. In this framework, a femtocell game is formulated, where the femtocell owners determine the proportion of femtocell resources shared with public users while the operator can maximize its own benefit by determining the ratio of revenue distribution to femtocell owners. The existence of the Nash equilibrium of the game is analyzed. Extensive simulations are conducted to show that the profit of the operator can be maximized while the service requirements of users can be maintained by the proposed framework.
{"title":"A spectrum-sharing rewarding framework for co-channel hybrid access femtocell networks","authors":"Chien-Han Chai, Yuan-Yao Shih, Ai-Chun Pang","doi":"10.1109/INFCOM.2013.6566836","DOIUrl":"https://doi.org/10.1109/INFCOM.2013.6566836","url":null,"abstract":"With the explosive growth of mobile data traffic, the femtocell technology is one of the proper solutions to enhance mobile service quality and system capacity for cellular networks. However, one of the key problems for femtocell deployment is to find appropriate access control in which mobile operators and users are willing to be involved. Among all kinds of access control modes, the hybrid access mode is considered as the most promising one, which allows femtocells to provide preferential access to femtocell owners and subscribers while other public users can access femtocells with certain restriction. Since all femtocell owners are selfish, how to provide enough incentives to the owners for sharing their femtocell resources is challenging. In this paper, we construct an economic framework for mobile operator and femtocell users by a game theoretical analysis and introduce the concept of profit sharing to provide a positive cycle to sustain the femtocell service. In this framework, a femtocell game is formulated, where the femtocell owners determine the proportion of femtocell resources shared with public users while the operator can maximize its own benefit by determining the ratio of revenue distribution to femtocell owners. The existence of the Nash equilibrium of the game is analyzed. Extensive simulations are conducted to show that the profit of the operator can be maximized while the service requirements of users can be maintained by the proposed framework.","PeriodicalId":206346,"journal":{"name":"2013 Proceedings IEEE INFOCOM","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128320890","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 : 2013-04-14DOI: 10.1109/INFCOM.2013.6566859
Lei Sun, Wenye Wang
It has been demonstrated that in wireless networks, Blackholes, which are typically generated by isolated node failures, and augmented by failure correlations, can easily result in devastating impact on network performance. Therefore, many solutions, such as routing protocols and restoration algorithms, are proposed to deal with Blackholes by identifying alternative paths to bypass these holes such that the effect of Blackholes can be mitigated. These advancements are based on an underlying premise that there exists at least one alternative path in the network. However, such a hypothesis remains an open question. In other words, we do not know whether the network is resilient to Blackholes or whether an alternative path exists. The answer to this question can complement our understanding of designing routing protocols, as well as topology evolution in the presence of random failures. In order to address this issue, we focus on the topology of Cognitive Radio Networks (CRNs) because of their phenomenal benefits in improving spectrum efficiency through opportunistic communications. Particularly, we first define two metrics, namely the failure occurrence probability p and failure connection function g(·), to characterize node failures and their spreading properties, respectively. Then we prove that each Blackhole is exponentially bounded based on percolation theory. By mapping failure spreading using a branching process, we further derive an upper bound on the expected size of Blackholes. With the observations from our analysis, we are able to find a sufficient condition for a resilient CRN in the presence of Blackholes through analysis and simulations.
{"title":"Understanding Blackholes in large-scale Cognitive Radio Networks under generic failures","authors":"Lei Sun, Wenye Wang","doi":"10.1109/INFCOM.2013.6566859","DOIUrl":"https://doi.org/10.1109/INFCOM.2013.6566859","url":null,"abstract":"It has been demonstrated that in wireless networks, Blackholes, which are typically generated by isolated node failures, and augmented by failure correlations, can easily result in devastating impact on network performance. Therefore, many solutions, such as routing protocols and restoration algorithms, are proposed to deal with Blackholes by identifying alternative paths to bypass these holes such that the effect of Blackholes can be mitigated. These advancements are based on an underlying premise that there exists at least one alternative path in the network. However, such a hypothesis remains an open question. In other words, we do not know whether the network is resilient to Blackholes or whether an alternative path exists. The answer to this question can complement our understanding of designing routing protocols, as well as topology evolution in the presence of random failures. In order to address this issue, we focus on the topology of Cognitive Radio Networks (CRNs) because of their phenomenal benefits in improving spectrum efficiency through opportunistic communications. Particularly, we first define two metrics, namely the failure occurrence probability p and failure connection function g(·), to characterize node failures and their spreading properties, respectively. Then we prove that each Blackhole is exponentially bounded based on percolation theory. By mapping failure spreading using a branching process, we further derive an upper bound on the expected size of Blackholes. With the observations from our analysis, we are able to find a sufficient condition for a resilient CRN in the presence of Blackholes through analysis and simulations.","PeriodicalId":206346,"journal":{"name":"2013 Proceedings IEEE INFOCOM","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128352642","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 : 2013-04-14DOI: 10.1109/INFCOM.2013.6566959
Jian Tan, S. Meng, Xiaoqiao Meng, Li Zhang
Improving data locality for MapReduce jobs is critical for the performance of large-scale Hadoop clusters, embodying the principle of moving computation close to data for big data platforms. Scheduling tasks in the vicinity of stored data can significantly diminish network traffic, which is crucial for system stability and efficiency. Though the issue on data locality has been investigated extensively for MapTasks, most of the existing schedulers ignore data locality for ReduceTasks when fetching the intermediate data, causing performance degradation. This problem of reducing the fetching cost for ReduceTasks has been identified recently. However, the proposed solutions are exclusively based on a greedy approach, relying on the intuition to place ReduceTasks to the slots that are closest to the majority of the already generated intermediate data. The consequence is that, in presence of job arrivals and departures, assigning the ReduceTasks of the current job to the nodes with the lowest fetching cost can prevent a subsequent job with even better match of data locality from being launched on the already taken slots. To this end, we formulate a stochastic optimization framework to improve the data locality for ReduceTasks, with the optimal placement policy exhibiting a threshold-based structure. In order to ease the implementation, we further propose a receding horizon control policy based on the optimal solution under restricted conditions. The improved performance is further validated through simulation experiments and real performance tests on our testbed.
{"title":"Improving ReduceTask data locality for sequential MapReduce jobs","authors":"Jian Tan, S. Meng, Xiaoqiao Meng, Li Zhang","doi":"10.1109/INFCOM.2013.6566959","DOIUrl":"https://doi.org/10.1109/INFCOM.2013.6566959","url":null,"abstract":"Improving data locality for MapReduce jobs is critical for the performance of large-scale Hadoop clusters, embodying the principle of moving computation close to data for big data platforms. Scheduling tasks in the vicinity of stored data can significantly diminish network traffic, which is crucial for system stability and efficiency. Though the issue on data locality has been investigated extensively for MapTasks, most of the existing schedulers ignore data locality for ReduceTasks when fetching the intermediate data, causing performance degradation. This problem of reducing the fetching cost for ReduceTasks has been identified recently. However, the proposed solutions are exclusively based on a greedy approach, relying on the intuition to place ReduceTasks to the slots that are closest to the majority of the already generated intermediate data. The consequence is that, in presence of job arrivals and departures, assigning the ReduceTasks of the current job to the nodes with the lowest fetching cost can prevent a subsequent job with even better match of data locality from being launched on the already taken slots. To this end, we formulate a stochastic optimization framework to improve the data locality for ReduceTasks, with the optimal placement policy exhibiting a threshold-based structure. In order to ease the implementation, we further propose a receding horizon control policy based on the optimal solution under restricted conditions. The improved performance is further validated through simulation experiments and real performance tests on our testbed.","PeriodicalId":206346,"journal":{"name":"2013 Proceedings IEEE INFOCOM","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128390701","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 : 2013-04-14DOI: 10.1109/INFCOM.2013.6567181
V. Arnaboldi, M. Conti, A. Passarella, F. Pezzoni
Online Social Networks are amongst the most important platforms for maintaining social relationships online, supporting content generation and exchange between users. They are therefore natural candidate to be the basis of future humancentric networks and data exchange systems, in addition to novel forms of Internet services exploiting the properties of human social relationships. Understanding the structural properties of OSN and how they are influenced by human behaviour is thus fundamental to design such human-centred systems. In this paper we analyse a real Twitter data set to investigate whether well known structures of human social networks identified in “offline” environments can also be identified in the social networks maintained by users on Twitter. According to the well known model proposed by Dunbar, offline social networks are formed of circles of relationships having different social characteristics (e.g., intimacy, contact frequency and size). These circles can be directly ascribed to cognitive constraints of human brain, that impose limits on the number of social relationships maintainable at different levels of emotional closeness. Our results indicate that a similar structure can also be found in the Twitter users' social networks. This suggests that the structure of social networks also in online environments are controlled by the same cognitive properties of human brain that operate offline.
{"title":"Ego networks in Twitter: An experimental analysis","authors":"V. Arnaboldi, M. Conti, A. Passarella, F. Pezzoni","doi":"10.1109/INFCOM.2013.6567181","DOIUrl":"https://doi.org/10.1109/INFCOM.2013.6567181","url":null,"abstract":"Online Social Networks are amongst the most important platforms for maintaining social relationships online, supporting content generation and exchange between users. They are therefore natural candidate to be the basis of future humancentric networks and data exchange systems, in addition to novel forms of Internet services exploiting the properties of human social relationships. Understanding the structural properties of OSN and how they are influenced by human behaviour is thus fundamental to design such human-centred systems. In this paper we analyse a real Twitter data set to investigate whether well known structures of human social networks identified in “offline” environments can also be identified in the social networks maintained by users on Twitter. According to the well known model proposed by Dunbar, offline social networks are formed of circles of relationships having different social characteristics (e.g., intimacy, contact frequency and size). These circles can be directly ascribed to cognitive constraints of human brain, that impose limits on the number of social relationships maintainable at different levels of emotional closeness. Our results indicate that a similar structure can also be found in the Twitter users' social networks. This suggests that the structure of social networks also in online environments are controlled by the same cognitive properties of human brain that operate offline.","PeriodicalId":206346,"journal":{"name":"2013 Proceedings IEEE INFOCOM","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128156067","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 : 2013-04-14DOI: 10.1109/INFCOM.2013.6566886
Wei Li, Xiuzhen Cheng, Tao Jing, Xiaoshuang Xing
The cooperation between the primary and the secondary users has attracted a lot of attention in cognitive radio networks. However, most existing research mainly focuses on the single-hop relay selection for a primary transmitter-receiver pair, which might not be able to fully explore the benefit brought by cooperative transmissions. In this paper, we study the problem of multi-hop relay selection by applying the network formation game. In order to mitigate interference and reduce delay, we propose a cooperation framework FTCO by considering the spectrum sharing in both the time and the frequency domain. Then we formulate the multi-hop relay selection problem as a network formation game, in which the multi-hop relay path is computed via performing the primary player's strategies in the form of link operations. We also devise a distributed dynamic algorithm PRADA to obtain a global-path stable network. Finally, we conduct extensive numerical experiments and our results indicate that cooperative multi-hop relaying can significantly benefit both the primary and the secondary network, and that the network graph resulted from our PRADA algorithm can achieve the global-path stability.
{"title":"Cooperative multi-hop relaying via network formation games in cognitive radio networks","authors":"Wei Li, Xiuzhen Cheng, Tao Jing, Xiaoshuang Xing","doi":"10.1109/INFCOM.2013.6566886","DOIUrl":"https://doi.org/10.1109/INFCOM.2013.6566886","url":null,"abstract":"The cooperation between the primary and the secondary users has attracted a lot of attention in cognitive radio networks. However, most existing research mainly focuses on the single-hop relay selection for a primary transmitter-receiver pair, which might not be able to fully explore the benefit brought by cooperative transmissions. In this paper, we study the problem of multi-hop relay selection by applying the network formation game. In order to mitigate interference and reduce delay, we propose a cooperation framework FTCO by considering the spectrum sharing in both the time and the frequency domain. Then we formulate the multi-hop relay selection problem as a network formation game, in which the multi-hop relay path is computed via performing the primary player's strategies in the form of link operations. We also devise a distributed dynamic algorithm PRADA to obtain a global-path stable network. Finally, we conduct extensive numerical experiments and our results indicate that cooperative multi-hop relaying can significantly benefit both the primary and the secondary network, and that the network graph resulted from our PRADA algorithm can achieve the global-path stability.","PeriodicalId":206346,"journal":{"name":"2013 Proceedings IEEE INFOCOM","volume":"83 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128700862","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 : 2013-04-14DOI: 10.1109/INFCOM.2013.6566860
Youngjune Gwon, H. T. Kung
We propose a spectrum analyzer that leverages many networked commodity sensor nodes, each of which samples its portion in a wideband spectrum. The sensors operate in parallel and transmit their measurements over a wireless network without performing any significant computations such as FFT. The measurements are forwarded to the backend of the system where spectrum analysis takes place. In particular, we propose a solution that compresses the raw measurements in a simple random linear projection and combines the compressed measurements from multiple sensors in-network. As a result, we achieve a substantial reduction in the network bandwidth requirement to operate the proposed system. We discover that the overall communication cost can be independent of the number of sensors and is affected only by sparsity of discretized spectrum under analysis. This principle founds the basis for a claim that our network-based spectrum analyzer can scale up the number of sensor nodes to process a very wide spectrum block potentially having a GHz bandwidth. We devise a novel recovery algorithm that systematically undoes compressive encoding and in-network combining done to the raw measurements, incorporating the least squares and I1-minimization decoding used in compressive sensing, and demonstrate that the algorithm can effectively restore an accurate estimate of the original data suitable for finegrained spectrum analysis. We present mathematical analysis and empirical evaluation of the system with software-defined radios.
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