Computational grids (CGs) are large scale, geographically distributed networks of computing resources spanning distinct management domains. The dynamic state of these resources is only observable with an uncertainty induced by various grid environmental factors. In order to address this uncertainty we explore the use of Markov chains to model the grid resource state dynamics. The simulation results show that the model provide a resource state prediction within a small margin of error.
{"title":"Probabilistic resource state estimation in networked environments: the case of computational grids","authors":"Y. Derbal","doi":"10.1109/CNSR.2005.50","DOIUrl":"https://doi.org/10.1109/CNSR.2005.50","url":null,"abstract":"Computational grids (CGs) are large scale, geographically distributed networks of computing resources spanning distinct management domains. The dynamic state of these resources is only observable with an uncertainty induced by various grid environmental factors. In order to address this uncertainty we explore the use of Markov chains to model the grid resource state dynamics. The simulation results show that the model provide a resource state prediction within a small margin of error.","PeriodicalId":166700,"journal":{"name":"3rd Annual Communication Networks and Services Research Conference (CNSR'05)","volume":"920 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123285450","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}
Although many multicast communication protocols have been recommended at IETF, reliable multicast communications currently rely on programs built at the application layer, e.g., multicast overlay. This is because there is a lack of reliable multicast protocols. This is even harder for the multicast capable routers to offer transparent reliable multicast services if receivers are on paths with drastically different path characteristics. In this paper, concept of multicast reliability integrated within routing algorithm is discussed. It is important to map reliability from transport layer to network layer, and subsequently from network layer to data link layer The novelty of the proposed design is to offer packet recovery mechanisms between every two intelligent routers. The resulting shortest-hop based reliability eliminates the retransmission request implosion problem and shortens the error recovery session time along any multicast tree. Consequently, the proposed design offers high goodput performance for multicasting important information in wired and wireless networks.
{"title":"Shortest-hop based reliable network multicast","authors":"K. Law, Daniel Siu","doi":"10.1109/CNSR.2005.57","DOIUrl":"https://doi.org/10.1109/CNSR.2005.57","url":null,"abstract":"Although many multicast communication protocols have been recommended at IETF, reliable multicast communications currently rely on programs built at the application layer, e.g., multicast overlay. This is because there is a lack of reliable multicast protocols. This is even harder for the multicast capable routers to offer transparent reliable multicast services if receivers are on paths with drastically different path characteristics. In this paper, concept of multicast reliability integrated within routing algorithm is discussed. It is important to map reliability from transport layer to network layer, and subsequently from network layer to data link layer The novelty of the proposed design is to offer packet recovery mechanisms between every two intelligent routers. The resulting shortest-hop based reliability eliminates the retransmission request implosion problem and shortens the error recovery session time along any multicast tree. Consequently, the proposed design offers high goodput performance for multicasting important information in wired and wireless networks.","PeriodicalId":166700,"journal":{"name":"3rd Annual Communication Networks and Services Research Conference (CNSR'05)","volume":"17 36","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114048160","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}
A novel system design to accommodate wireless computer video (WVGA) is presented. A simple, yet efficient variable threshold frame differencing scheme is developed in this paper that allows lossless computer video compression ratio's up to 100%, depending on what occurs on the screen. Using this scheme, only the differences between frames are sent through the channel. The compressed video stream still requires a very high speed wireless link. A 360 Mbps wireless OFDM link is simulated to cover a distance of 6 m in an indoor environment. The high bit rate comes at the expense of using 1/2 of the unlicensed band from 5.15-5.35 GHz (lower UNII band) per user. There is a resulting user count of 2 per 6 meter cell. However, the data rate allows a user to play full screen video files. The scheme can be modified to accommodate a higher density network of users who spend a lot of time surfing the Internet or word processing and who are not interested in viewing full screen video files all of the time.
{"title":"Wireless video graphics array system design","authors":"A. Sampson, Z. Chen","doi":"10.1109/CNSR.2005.62","DOIUrl":"https://doi.org/10.1109/CNSR.2005.62","url":null,"abstract":"A novel system design to accommodate wireless computer video (WVGA) is presented. A simple, yet efficient variable threshold frame differencing scheme is developed in this paper that allows lossless computer video compression ratio's up to 100%, depending on what occurs on the screen. Using this scheme, only the differences between frames are sent through the channel. The compressed video stream still requires a very high speed wireless link. A 360 Mbps wireless OFDM link is simulated to cover a distance of 6 m in an indoor environment. The high bit rate comes at the expense of using 1/2 of the unlicensed band from 5.15-5.35 GHz (lower UNII band) per user. There is a resulting user count of 2 per 6 meter cell. However, the data rate allows a user to play full screen video files. The scheme can be modified to accommodate a higher density network of users who spend a lot of time surfing the Internet or word processing and who are not interested in viewing full screen video files all of the time.","PeriodicalId":166700,"journal":{"name":"3rd Annual Communication Networks and Services Research Conference (CNSR'05)","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128319077","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}
In this paper, we improve the conventional iterative soft interference cancellation by introducing the partial cancellation technique and minimum mean square error (MMSE) multiuser detection technique in an uplink turbo-coded multicarrier code division multiple access (MC-CDMA) system. The performance of our proposed receiver is evaluated in Rayleigh multipath fading channel by using computer simulation. Simulation results demonstrate the advantages of the proposed technique over the conventional technique.
{"title":"Iterative partial soft interference cancellation with MMSE multiuser detection for uplink turbo-coded MC-CDMA system","authors":"P. Kumpoopong, S. Kunaruttanapruk, S. Jitapunkul","doi":"10.1109/CNSR.2005.38","DOIUrl":"https://doi.org/10.1109/CNSR.2005.38","url":null,"abstract":"In this paper, we improve the conventional iterative soft interference cancellation by introducing the partial cancellation technique and minimum mean square error (MMSE) multiuser detection technique in an uplink turbo-coded multicarrier code division multiple access (MC-CDMA) system. The performance of our proposed receiver is evaluated in Rayleigh multipath fading channel by using computer simulation. Simulation results demonstrate the advantages of the proposed technique over the conventional technique.","PeriodicalId":166700,"journal":{"name":"3rd Annual Communication Networks and Services Research Conference (CNSR'05)","volume":"213 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132129123","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}
The standard frame sequence of an MPEG encoded video stream is suitable for normal playback. However, its inter-frame dependency makes it difficult to use it for interactive playback modes, such as play backward, jump or fast forward/backward. A scalable streaming system is required to serve videos to a large number of clients and it should share a single server stream among many clients. However, different interactive clients generally ask for different playback sequences. Hence, their streams cannot be grouped and served together by a single server stream. Therefore, as the frequency of interaction increases, an ordinary scalable streaming service becomes a non-scalable service. In this paper, we have proposed an improved proxy-based streaming scheme over the Internet. We have used video segmentation and hybrid temporal-data-partition scalable video encoding to create suitable playback sequence for interactive playback modes. We have used prefix and smoothing buffers at the proxy to make our scheme scalable. Simulation results show that our streaming scheme remains fully scalable even when all the clients are highly interactive. By using certain part of the available server-proxy network bandwidth and proxy buffers, our streaming scheme can support large numbers of clients. As the level of interaction increases the relative bandwidth and the buffer requirement decreases.
{"title":"An interactive scalable multimedia streaming scheme for VBR-encoded videos","authors":"M. Kabir, E. Manning, G. Shoja","doi":"10.1109/CNSR.2005.23","DOIUrl":"https://doi.org/10.1109/CNSR.2005.23","url":null,"abstract":"The standard frame sequence of an MPEG encoded video stream is suitable for normal playback. However, its inter-frame dependency makes it difficult to use it for interactive playback modes, such as play backward, jump or fast forward/backward. A scalable streaming system is required to serve videos to a large number of clients and it should share a single server stream among many clients. However, different interactive clients generally ask for different playback sequences. Hence, their streams cannot be grouped and served together by a single server stream. Therefore, as the frequency of interaction increases, an ordinary scalable streaming service becomes a non-scalable service. In this paper, we have proposed an improved proxy-based streaming scheme over the Internet. We have used video segmentation and hybrid temporal-data-partition scalable video encoding to create suitable playback sequence for interactive playback modes. We have used prefix and smoothing buffers at the proxy to make our scheme scalable. Simulation results show that our streaming scheme remains fully scalable even when all the clients are highly interactive. By using certain part of the available server-proxy network bandwidth and proxy buffers, our streaming scheme can support large numbers of clients. As the level of interaction increases the relative bandwidth and the buffer requirement decreases.","PeriodicalId":166700,"journal":{"name":"3rd Annual Communication Networks and Services Research Conference (CNSR'05)","volume":"111 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132237101","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}
We present a method of integrating constrained sequence (CS) and error control (EC) codes for digital communication systems. This technique is based on multimode coding where a single source word (SW) is represented by a set of complementary EC code words (CWs). From this set the encoder selects the CW that best meets the CS goals of the system. These goals are to have balanced transmission and a high number of transitions to aid in clock recovery. The decoding structure avoids the problem of CS error propagation by performing error correction before decoding the CS code. A hardware implementation was constructed to verify code operation and to measure the power spectral density (PSD) which is shown to match calculations. The PSD plots show that the encoded sequence has a null at 0 Hz and thus it is dc-free. Furthermore, BER simulations demonstrate the superior performance of this combined EC and CS code on a dc-constrained noisy channel.
{"title":"An integrated error control and constrained sequence code based on multimode coding","authors":"A. Hughes, I. Fair","doi":"10.1109/CNSR.2005.22","DOIUrl":"https://doi.org/10.1109/CNSR.2005.22","url":null,"abstract":"We present a method of integrating constrained sequence (CS) and error control (EC) codes for digital communication systems. This technique is based on multimode coding where a single source word (SW) is represented by a set of complementary EC code words (CWs). From this set the encoder selects the CW that best meets the CS goals of the system. These goals are to have balanced transmission and a high number of transitions to aid in clock recovery. The decoding structure avoids the problem of CS error propagation by performing error correction before decoding the CS code. A hardware implementation was constructed to verify code operation and to measure the power spectral density (PSD) which is shown to match calculations. The PSD plots show that the encoded sequence has a null at 0 Hz and thus it is dc-free. Furthermore, BER simulations demonstrate the superior performance of this combined EC and CS code on a dc-constrained noisy channel.","PeriodicalId":166700,"journal":{"name":"3rd Annual Communication Networks and Services Research Conference (CNSR'05)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129387554","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}
Nowadays, more and more people are accessing the Internet wirelessly via many different mobile devices such as notebooks, PDAs and smartphones. The heterogeneity of the various portable devices makes the experience of using the Internet much different from using a desktop computer. Web pages must be adapted to the context of computing for efficient delivery and user satisfaction. The FACADE framework was developed as a context-aware adaptation tool for single-source Web pages. However, due to the initial steep learning curve to successfully create single-source Web pages, a Web page authoring tool is needed to automatically generate the XHTML code. This short paper describes the initial efforts to develop such a tool. It provides the author with a WYSIWYG graphical user interface and the ability to author context-adaptable Web pages for multiple end user devices simultaneously.
{"title":"A multi-context visual Web page authoring tool","authors":"Beika Zhan, Bernd J. Kurz","doi":"10.1109/CNSR.2005.13","DOIUrl":"https://doi.org/10.1109/CNSR.2005.13","url":null,"abstract":"Nowadays, more and more people are accessing the Internet wirelessly via many different mobile devices such as notebooks, PDAs and smartphones. The heterogeneity of the various portable devices makes the experience of using the Internet much different from using a desktop computer. Web pages must be adapted to the context of computing for efficient delivery and user satisfaction. The FACADE framework was developed as a context-aware adaptation tool for single-source Web pages. However, due to the initial steep learning curve to successfully create single-source Web pages, a Web page authoring tool is needed to automatically generate the XHTML code. This short paper describes the initial efforts to develop such a tool. It provides the author with a WYSIWYG graphical user interface and the ability to author context-adaptable Web pages for multiple end user devices simultaneously.","PeriodicalId":166700,"journal":{"name":"3rd Annual Communication Networks and Services Research Conference (CNSR'05)","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132183958","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}
This article is an overview of the GIPSY demand migration system (DMS). This system brings a demand driven execution engine like the one used in the GIPSY to a high level of distributiveness and interoperability of operational nodes, by mixing together advanced distributed technologies. The main demand migration system's artifacts are discussed, and their different distributions within the GIPSY are surveyed. The article concludes with a presentation of a successful GIPSY demand migration implementation, based on JINI. This paper describes only the aspects of the GIPSY demand migration, i.e. it does not deal with load balancing and efficiency aspects of the GIPSY, as these are to be tackled by other subsystems of the GIPSY.
{"title":"A general architecture for demand migration in a demand-driven execution engine in a heterogeneous and distributed environment","authors":"Emil Vassev, J. Paquet","doi":"10.1109/CNSR.2005.9","DOIUrl":"https://doi.org/10.1109/CNSR.2005.9","url":null,"abstract":"This article is an overview of the GIPSY demand migration system (DMS). This system brings a demand driven execution engine like the one used in the GIPSY to a high level of distributiveness and interoperability of operational nodes, by mixing together advanced distributed technologies. The main demand migration system's artifacts are discussed, and their different distributions within the GIPSY are surveyed. The article concludes with a presentation of a successful GIPSY demand migration implementation, based on JINI. This paper describes only the aspects of the GIPSY demand migration, i.e. it does not deal with load balancing and efficiency aspects of the GIPSY, as these are to be tackled by other subsystems of the GIPSY.","PeriodicalId":166700,"journal":{"name":"3rd Annual Communication Networks and Services Research Conference (CNSR'05)","volume":"2014 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114443847","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}
The development of information technologies and the expansion of the Internet have brought us to an environment, which is filled with huge amounts of information. A number of content management systems have appeared which aim to support the management of these large amounts of content. Many CMS solutions are currently based on client/server model with a central server for storage and management. However, such centralized systems lack scalability and reliability. P2P-based CMS solutions can solve the scalable problem, but they have some shortcomings such as security, reliability, etc. We present a P2P-based content management architecture (PCMA) with some grid properties such as security, reliability, etc., which combines the advantages of the above two models and avoids their shortcomings. PCMA can exactly discovery services and scales much better.
{"title":"Design of a distributed P2P-based grid content management architecture","authors":"Qian Zhang, Yu Sun, Zheng Liu, Xia Zhang, Xuezhi Wen","doi":"10.1109/CNSR.2005.30","DOIUrl":"https://doi.org/10.1109/CNSR.2005.30","url":null,"abstract":"The development of information technologies and the expansion of the Internet have brought us to an environment, which is filled with huge amounts of information. A number of content management systems have appeared which aim to support the management of these large amounts of content. Many CMS solutions are currently based on client/server model with a central server for storage and management. However, such centralized systems lack scalability and reliability. P2P-based CMS solutions can solve the scalable problem, but they have some shortcomings such as security, reliability, etc. We present a P2P-based content management architecture (PCMA) with some grid properties such as security, reliability, etc., which combines the advantages of the above two models and avoids their shortcomings. PCMA can exactly discovery services and scales much better.","PeriodicalId":166700,"journal":{"name":"3rd Annual Communication Networks and Services Research Conference (CNSR'05)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129122289","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}
W. Goodridge, W. Robertson, W. Phillips, S. Sivakumar
Heuristic QoS algorithms under strict constraints perform poorly in terms of finding a path that is suitable for a user's QoS needs-the multiple constraint path problem (MCP). Exact QoS algorithms, on the other hand, guarantee that a path satisfying user needs would be found and offer a more realistic approach for solving the MCP problem in view of the fact that the NP-complete character of graphs are not common in real networks. This fact has driven approaches like the SAMCRA and A*prune algorithms. However, these algorithms still have very high running times relative to heuristic approaches. When QoS routing algorithms are used in online traffic engineering (TE) environments it may be necessary to route thousands of traffic flows each minute. Exact algorithms simply cannot work in such environments. We propose a heuristic algorithm that is suitable for working in an online TE environment. Simulations show that this algorithm produce high success rates in terms of finding suitable constraint paths for user flows while at the same time having execution times comparable to another heuristic based algorithms.
{"title":"Heuristic constraint-path routing decision system","authors":"W. Goodridge, W. Robertson, W. Phillips, S. Sivakumar","doi":"10.1109/CNSR.2005.36","DOIUrl":"https://doi.org/10.1109/CNSR.2005.36","url":null,"abstract":"Heuristic QoS algorithms under strict constraints perform poorly in terms of finding a path that is suitable for a user's QoS needs-the multiple constraint path problem (MCP). Exact QoS algorithms, on the other hand, guarantee that a path satisfying user needs would be found and offer a more realistic approach for solving the MCP problem in view of the fact that the NP-complete character of graphs are not common in real networks. This fact has driven approaches like the SAMCRA and A*prune algorithms. However, these algorithms still have very high running times relative to heuristic approaches. When QoS routing algorithms are used in online traffic engineering (TE) environments it may be necessary to route thousands of traffic flows each minute. Exact algorithms simply cannot work in such environments. We propose a heuristic algorithm that is suitable for working in an online TE environment. Simulations show that this algorithm produce high success rates in terms of finding suitable constraint paths for user flows while at the same time having execution times comparable to another heuristic based algorithms.","PeriodicalId":166700,"journal":{"name":"3rd Annual Communication Networks and Services Research Conference (CNSR'05)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130512585","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}
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