{"title":"Bounds on the mixing time and partial cover of ad-hoc and sensor networks","authors":"C. Avin, Gunes Ercal","doi":"10.1109/EWSN.2005.1461994","DOIUrl":"https://doi.org/10.1109/EWSN.2005.1461994","url":null,"abstract":"In [Avin, C et al., (2004)], the authors proposed the partial cover of a random walk on a broadcast network to be used to gather information and supported their proposal with experimental results. In this paper, we demonstrate analytically that for sufficiently large broadcast radius r, the partial cover of a random walk on a random broadcast network is in fact efficient and generates a good distribution of the visited nodes. Our result is based on bounding the conductance, which intuitively measures the amount of bottlenecks in a graph. We show that the conductance of a random broadcast network in a unit square is /spl otimes/(r) with high probability, and this bound allows us to analyze properties of the random walk such as mixing time and load balancing. We find that for the random walk to be both efficient and have a high quality cover and partial cover (i.e. rapid mixing), radius at least r/sub rapid/ = /spl otimes/(1/poly (log n)) is sufficient and necessary. Experimental results on the random geometric graphs, namely graphs that represent broadcast networks, that resemble the conductance of the 3-dimensional grid indicate that the analytical bounds on efficiency, namely cover time and partial cover time, are not tight. In particular, r = /spl otimes/(1/n/sup 1/3/) is sufficient radius to obtain optimal cover time and partial cover time.","PeriodicalId":426477,"journal":{"name":"Proceeedings of the Second European Workshop on Wireless Sensor Networks, 2005.","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124669779","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}
{"title":"Link-layer jamming attacks on S-MAC","authors":"Yee Wei Law, P. Hartel, J. D. Hartog, P. Havinga","doi":"10.1109/EWSN.2005.1462013","DOIUrl":"https://doi.org/10.1109/EWSN.2005.1462013","url":null,"abstract":"We argue that among denial-of-service (DoS) attacks, link-layer jamming is a more attractive option to attackers than radio jamming is. By exploiting the semantics of the link-layer protocol (aka MAC protocol), an attacker can achieve better efficiency than blindly jamming the radio signals alone. In this paper, we investigate some jamming attacks on S-MAC, the level of effectiveness and efficiency the attacks can potentially achieve and a countermeasure that can be implemented against one of these attacks.","PeriodicalId":426477,"journal":{"name":"Proceeedings of the Second European Workshop on Wireless Sensor Networks, 2005.","volume":"165 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127300866","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}
{"title":"BitMAC: a deterministic, collision-free, and robust MAC protocol for sensor networks","authors":"M. Ringwald, K. Römer","doi":"10.1109/EWSN.2005.1461999","DOIUrl":"https://doi.org/10.1109/EWSN.2005.1461999","url":null,"abstract":"Collisions are a source of inefficiency in contention-based MAC protocols that should be reduced to a minimum. We show that concurrent multiple access to a communication channel will, however, not necessarily lead to a collision with undesirable effects. Rather, we demonstrate that it is possible for a receiver to hear the bitwise \"or\" of the transmissions of multiple synchronized senders within communication range. This unconventional communication model allows the efficient implementation of a number of basic operations that serve as a foundation for BitMAC: a deterministic, collision-free, and robust MAC protocol that is tailored to dense sensor networks, where nodes report sensory data over multiple hops to a sink.","PeriodicalId":426477,"journal":{"name":"Proceeedings of the Second European Workshop on Wireless Sensor Networks, 2005.","volume":"92 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124217879","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}