R. V. Prasad, A. Sangwan, H. Jamadagni, M. Chiranth, R. Sah, V. Gaurav
{"title":"Comparison of voice activity detection algorithms for VoIP","authors":"R. V. Prasad, A. Sangwan, H. Jamadagni, M. Chiranth, R. Sah, V. Gaurav","doi":"10.1109/ISCC.2002.1021726","DOIUrl":"https://doi.org/10.1109/ISCC.2002.1021726","url":null,"abstract":"We discuss techniques for voice activity detection (VAD) for voice over Internet Protocol (VoIP). VAD aids in saving the bandwidth requirement of a voice session, thereby increasing the bandwidth efficiently. We compare the quality of speech, level of compression and computational complexity for three time-domain and three frequency-domain VAD algorithms. Implementation of time-domain algorithms is computationally simple. However, better speech quality is obtained with the frequency-domain algorithms. A comparison of the merits and demerits along with the subjective quality of speech after removal of silence periods is presented for all the algorithms. A quantitative measurement of speech quality for different algorithms is also presented.","PeriodicalId":261743,"journal":{"name":"Proceedings ISCC 2002 Seventh International Symposium on Computers and Communications","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132348872","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":"SIP call setup delay in 3G networks","authors":"I. Curcio, Miikka Lundan","doi":"10.1109/ISCC.2002.1021770","DOIUrl":"https://doi.org/10.1109/ISCC.2002.1021770","url":null,"abstract":"In this paper, call setup time in Session Initiation Protocol (SIP)-based videotelephony is analyzed. We used a 3G network emulator to measure post-dialing delay, answer-signal delay and call-release delay. The results are compared to local, national, international and overseas intranet LAN calls. Furthermore, we have also studied the effect SIP calls over lossy channels with restricted bandwidth, typical of mobile network signaling bearers.","PeriodicalId":261743,"journal":{"name":"Proceedings ISCC 2002 Seventh International Symposium on Computers and Communications","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134624807","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":"Introducing distribution into applications: a reflective approach for transparency and dynamic fine-grained object allocation","authors":"A. Stefano, G. Pappalardo, E. Tramontana","doi":"10.1109/ISCC.2002.1021740","DOIUrl":"https://doi.org/10.1109/ISCC.2002.1021740","url":null,"abstract":"Developing distributed software systems is a complex activity that involves facing not only the problems of a specific application, but also those typical of distribution. Computational reflection supplies a means to handle different concerns with distinct components and a framework in which the latter can interact smoothly. We propose a reflective software architecture that encapsulates distribution concerns within components that are separated from and independent of those addressing functional concerns. The proposed architecture achieves a thorough management of distribution and in particular provides a means to dynamically adapt allocation policies to the characteristics of application objects, available hosts and changes of the distributed environment. The proposed approach is helpful for achieving the incremental development of easy to evolve software systems. In particular, we discuss the benefits of applying it to existing Web and e-commerce applications.","PeriodicalId":261743,"journal":{"name":"Proceedings ISCC 2002 Seventh International Symposium on Computers and Communications","volume":"116 5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115051293","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":"Scheduling real time parallel structure on cluster computing","authors":"R. Ammar, A. Alhamdan","doi":"10.1109/ISCC.2002.1021660","DOIUrl":"https://doi.org/10.1109/ISCC.2002.1021660","url":null,"abstract":"Scheduling a large number of high performance computing applications on a cluster-computing environment is a complex task. This becomes more critical in real time systems. Efficient scheduling strategies are critically important to achieving good performance. A cluster scheduler without enough knowledge of the state of the cluster and the scheduled tasks cannot adequately manage the cluster resources. Accordingly, the available processing power of the participating nodes may experience uncontrolled fragmentation. Thus, some of the submitted applications may be rejected due to tasks missing their deadlines. The literature on scheduling real-time task graphs is much less extensive, especially for providing timing guarantees while maximizing the processing power utilization. In this paper, we present a framework for allocating and scheduling real-time applications represented as parallel task graphs on a cluster. We utilize the available processing power on each processor to accommodate as many tasks as possible while satisfying the required deadline of each task. The algorithm also reduces the communication cost among tasks and the possibility of processing power fragmentation.","PeriodicalId":261743,"journal":{"name":"Proceedings ISCC 2002 Seventh International Symposium on Computers and Communications","volume":"64 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114309062","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":"Using distributed component model for active service deployment","authors":"R. Kilany, A. Serhrouchni","doi":"10.1109/ISCC.2002.1021688","DOIUrl":"https://doi.org/10.1109/ISCC.2002.1021688","url":null,"abstract":"This paper presents a novel active architecture for building and deploying network services: HABA, hyper active components architecture. At the architectural level, HABA defines an active node whose functionalities are divided into the node operating system, the execution environment, and the active applications. At the implementation level, HABA is a component-based platform where new components could be added and deployed, in order to modify network node behavior dynamically. Applications can communicate across multi-tiered heterogeneous environments, and across Internet and intranet structures. Interoperability with ANTS is achieved by \"composition\". At the deployment level, HABA uses an active node approach, and offers a parallel controlled deployment mode and a sequential by request mode. In terms of security, HABA offers different security levels according to service profiles. Authentication of deployed code, and protection of nodes, is achieved by the deployment of certificates on the nodes.","PeriodicalId":261743,"journal":{"name":"Proceedings ISCC 2002 Seventh International Symposium on Computers and Communications","volume":"216 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113980667","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}
Ren Wang, Massimo Valla, M. Sanadidi, Bryan C H Kwok, Fai Ng, M. Gerla
{"title":"Efficiency/friendliness tradeoffs in TCP Westwood","authors":"Ren Wang, Massimo Valla, M. Sanadidi, Bryan C H Kwok, Fai Ng, M. Gerla","doi":"10.1109/ISCC.2002.1021694","DOIUrl":"https://doi.org/10.1109/ISCC.2002.1021694","url":null,"abstract":"We propose a refinement of TCP Westwood which allows management of the efficiency/friendliness-to-NewReno tradeoff. We show that the refined TCP Westwood is able to achieve higher efficiency yet at the same time maintain friendliness. TCP Westwood (TCPW) implements a novel window congestion control algorithm based on available bandwidth estimation. The performance of TCPW has been promising, exceeding that of TCP NewReno in high speed and/or wired/wireless networks. However, under certain circumstances, TCP NewReno may experience some performance degradation because TCPW possesses more information and thus can take better advantage of available bandwidth. We propose combining the original TCPW sampling strategy that produces available bandwidth estimates (BE), with a new strategy that produces rate estimates (RE). Our studies show that RE works best when packet losses are mostly due to congestion. If on the other hand, the packet losses are mostly due to link errors, BE gives better performance. To achieve the \"best of all worlds\", we introduce a method we call combined rate and bandwidth estimation (CRB). A connection first infers the predominant cause of packet losses, and then uses the most appropriate estimation method. We also introduce the efficiency/friendliness tradeoff graph that provides better tradeoff visualization. In our experiments, we found that CRB provides a better compromise between efficiency and friendliness, and the means to manage such a tradeoff.","PeriodicalId":261743,"journal":{"name":"Proceedings ISCC 2002 Seventh International Symposium on Computers and Communications","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125233423","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":"Network constrained smoothing: enhanced multiplexing of MPEG-4 video","authors":"C. Bewick, R. Pereira, M. Merabti","doi":"10.1109/ISCC.2002.1021666","DOIUrl":"https://doi.org/10.1109/ISCC.2002.1021666","url":null,"abstract":"Interactive multimedia applications over multi-hop cell or packet-switched networks have strict bounds on delay, loss, and jitter. Much research has focused on how best to handle the networking issues related to supporting quality of service (QoS) contracts without compromising network efficiency, i.e. improving network utilisation, and reducing connection packet loss and late delivery. This paper describes our novel technique, network constrained smoothing, for smoothing video traffic into a server-side transmission schedule. Our approach combines QoS metrics about video connections together with network loading information in an algorithm that divides the schedule into equal-sized intervals of constant bit-rate. We evaluate performance by simulation and compare with an existing smoothing technique, optimal smoothing. We show the benefits of using network constrained smoothing to synchronise independent multimedia streams. The results show reductions in network loading at peak times and provide manageable information for routers about currently supported multimedia traffic.","PeriodicalId":261743,"journal":{"name":"Proceedings ISCC 2002 Seventh International Symposium on Computers and Communications","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129301022","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}
Xiaohui Yuan, B. Buckles, Zhaoshan Yuan, Jian Zhang
{"title":"Mining negative association rules","authors":"Xiaohui Yuan, B. Buckles, Zhaoshan Yuan, Jian Zhang","doi":"10.1109/ISCC.2002.1021739","DOIUrl":"https://doi.org/10.1109/ISCC.2002.1021739","url":null,"abstract":"The focus of this paper is the discovery of negative association rules. Such association rules are complementary to the sorts of association rules most often encountered in the literature and have the forms of X/spl rarr/ -Y or -X/spl rarr/Y. We present a rule discovery algorithm that finds a useful subset of valid negative rules. In generating negative rules, we employ a hierarchical graph-structured taxonomy of domain terms. A taxonomy containing classification information records the similarity between items. Given the taxonomy, sibling rules, duplicated from positive rules with a couple of items replaced, are derived together with their estimated confidence. Those sibling rules that bring big confidence deviation are considered candidate negative rules. Our study shows that negative association rules can be discovered efficiently from large database.","PeriodicalId":261743,"journal":{"name":"Proceedings ISCC 2002 Seventh International Symposium on Computers and Communications","volume":"115 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124570312","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":"Differentiated services: an experimental vs. simulated case study","authors":"S. Andreozzi","doi":"10.1109/ISCC.2002.1021705","DOIUrl":"https://doi.org/10.1109/ISCC.2002.1021705","url":null,"abstract":"This paper aims to provide a proof of concept of the accuracy of simulations for studying advanced networking. The particular target technology is the differentiated services (DiffServ) architecture. The method has been to apply experimental activities conducted in a real network to a simulation environment, to gather the same performance parameters and to compare results. A worthy re-engineering of the DiffServ module of the deployed software program has been carried out and significant contribution have been made to overcome the encountered limitations and to enrich its modeling capabilities. Final results give useful suggestions for a more critical approach to simulations targeted at studying advanced networking.","PeriodicalId":261743,"journal":{"name":"Proceedings ISCC 2002 Seventh International Symposium on Computers and Communications","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130093639","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":"A study of QoS performance for real time applications over a differentiated services network","authors":"Evi Tsolakou, E. Nikolouzou, I. Venieris","doi":"10.1109/ISCC.2002.1021707","DOIUrl":"https://doi.org/10.1109/ISCC.2002.1021707","url":null,"abstract":"The differentiated service architecture (DiffServ) is currently a popular research topic as a low-cost method to provide quality of service to the different applications in the Internet. This paper addresses the definition and deployment of specific network services in a DiffServ environment. Each network service is appropriate for a specific type of traffic and is realized through its own network mechanisms, which are the traffic classes. The focus of the paper is the services appropriate for real time delay-sensitive applications such as voice and video. Different traffic control algorithms are studied for the implementation of the proposed services. Simulation results show that the proposed traffic control mechanisms provide hard performance guarantees to different flows.","PeriodicalId":261743,"journal":{"name":"Proceedings ISCC 2002 Seventh International Symposium on Computers and Communications","volume":"227 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116370664","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}