Pub Date : 2001-07-04DOI: 10.1109/EURCON.2001.937804
G. Alsop, C. Wills
This paper considers whether communications theory can help us to understand better the social and juridical impacts of new telecommunications services, particularly in relation to e-democracy and e-government.
{"title":"Technology and democracy: a panacea for government?","authors":"G. Alsop, C. Wills","doi":"10.1109/EURCON.2001.937804","DOIUrl":"https://doi.org/10.1109/EURCON.2001.937804","url":null,"abstract":"This paper considers whether communications theory can help us to understand better the social and juridical impacts of new telecommunications services, particularly in relation to e-democracy and e-government.","PeriodicalId":205662,"journal":{"name":"EUROCON'2001. International Conference on Trends in Communications. Technical Program, Proceedings (Cat. No.01EX439)","volume":"41 4","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131486741","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 : 2001-07-04DOI: 10.1109/EURCON.2001.938117
R. Radovic, I. crkvenac, S. Srbljic
The rapid improvement of hardware performance and the constantly growing bandwidth of computers have encouraged the development of communications based on computer networks. The first step in this direction is the definition of a set of protocols that will enable the design and implementation of various multimedia communication services. SIP (session initiation protocol) is a protocol for initiating multimedia conferences, and is a proposed standard, but its behavior is still not formally defined. We give a formal definition of the behavior of SIP end systems in the form of automata that include all features currently supported by SIP. The automata are defined using UML. This greatly simplifies the implementation of SIP systems compatibility between different systems based on SIP, because there are software tools that can translate UML specifications directly into the high-level languages (e.g., C++, Java).
{"title":"Formal definition of SIP end systems behavior","authors":"R. Radovic, I. crkvenac, S. Srbljic","doi":"10.1109/EURCON.2001.938117","DOIUrl":"https://doi.org/10.1109/EURCON.2001.938117","url":null,"abstract":"The rapid improvement of hardware performance and the constantly growing bandwidth of computers have encouraged the development of communications based on computer networks. The first step in this direction is the definition of a set of protocols that will enable the design and implementation of various multimedia communication services. SIP (session initiation protocol) is a protocol for initiating multimedia conferences, and is a proposed standard, but its behavior is still not formally defined. We give a formal definition of the behavior of SIP end systems in the form of automata that include all features currently supported by SIP. The automata are defined using UML. This greatly simplifies the implementation of SIP systems compatibility between different systems based on SIP, because there are software tools that can translate UML specifications directly into the high-level languages (e.g., C++, Java).","PeriodicalId":205662,"journal":{"name":"EUROCON'2001. International Conference on Trends in Communications. Technical Program, Proceedings (Cat. No.01EX439)","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124363729","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 : 2001-07-04DOI: 10.1109/EURCON.2001.937768
Kwang-Fu Li, Yueh-Hsia Tsai, Chia-Ching Li
In this paper, we present a new algorithm, the find-reassemble-path algorithm, for finding two node disjoint paths with lower cost than the original heuristics. We use the approach that reverses the directions of the arcs of the first shortest path, instead of deleting all the nodes on the path and all the arcs incident to the path, and then find second paths on the new graph. Finally, we use these two paths to reassemble into two node disjoint paths. There are four major steps in this algorithm. The first two steps are used to find paths and the last two steps are used to reassemble paths.
{"title":"Find-reassemble-path algorithm for finding node disjoint paths in telecommunications networks with two technologies","authors":"Kwang-Fu Li, Yueh-Hsia Tsai, Chia-Ching Li","doi":"10.1109/EURCON.2001.937768","DOIUrl":"https://doi.org/10.1109/EURCON.2001.937768","url":null,"abstract":"In this paper, we present a new algorithm, the find-reassemble-path algorithm, for finding two node disjoint paths with lower cost than the original heuristics. We use the approach that reverses the directions of the arcs of the first shortest path, instead of deleting all the nodes on the path and all the arcs incident to the path, and then find second paths on the new graph. Finally, we use these two paths to reassemble into two node disjoint paths. There are four major steps in this algorithm. The first two steps are used to find paths and the last two steps are used to reassemble paths.","PeriodicalId":205662,"journal":{"name":"EUROCON'2001. International Conference on Trends in Communications. Technical Program, Proceedings (Cat. No.01EX439)","volume":"70 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127548640","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 : 2001-07-04DOI: 10.1109/EURCON.2001.938161
R. Vích, J. Pribil, Z. Smekan
Speech is an analog sound signal produced by exciting the human vocal tract. The magnitude response of the vocal tract exhibits both peaks (formants) and valleys (antiformants). Vocal tract models are differentiated according to whether they model the formants alone (LPC models) or also antiformants (ARMA and cepstral models). New structures are proposed for an effective realization of cepstral vocal tract models that model both formants and antiformants.
{"title":"New cepstral zero-pole vocal tract models for TTS synthesis","authors":"R. Vích, J. Pribil, Z. Smekan","doi":"10.1109/EURCON.2001.938161","DOIUrl":"https://doi.org/10.1109/EURCON.2001.938161","url":null,"abstract":"Speech is an analog sound signal produced by exciting the human vocal tract. The magnitude response of the vocal tract exhibits both peaks (formants) and valleys (antiformants). Vocal tract models are differentiated according to whether they model the formants alone (LPC models) or also antiformants (ARMA and cepstral models). New structures are proposed for an effective realization of cepstral vocal tract models that model both formants and antiformants.","PeriodicalId":205662,"journal":{"name":"EUROCON'2001. International Conference on Trends in Communications. Technical Program, Proceedings (Cat. No.01EX439)","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130818858","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 : 2001-07-04DOI: 10.1109/EURCON.2001.937759
Lie-liang Yang, L. Hanzo
In this contribution, we investigate the performance of Reed-Solomon (RS) coded DS-CDMA using noncoherent M-ary orthogonal modulation over multipath Rayleigh fading channels. 'Errors-and-erasures' RS decoding is considered, where erasures are declared based on various erasure insertion schemes, such as the maximum output threshold test (OTT), ratio threshold test (RTT) and the joint maximum output and ratio threshold test (MOR-TT). Furthermore, the performance of 'errors-and-erasures' decoding employing the joint MOR-TT is compared to that of 'error-correction-only' decoding and to that of 'errors-and-erasures' decoding using the OTT as well as the RTT. The numerical results show that, when using 'errors-and-erasures' decoding, RS codes of a given code rate can achieve a significantly higher coding gain than without erasure information, and that the MOR-TT technique outperforms both the RTT and the OTT techniques.
{"title":"'Errors-and-erasures' decoding in RS coded DS-CDMA using noncoherent M-ary orthogonal modulation","authors":"Lie-liang Yang, L. Hanzo","doi":"10.1109/EURCON.2001.937759","DOIUrl":"https://doi.org/10.1109/EURCON.2001.937759","url":null,"abstract":"In this contribution, we investigate the performance of Reed-Solomon (RS) coded DS-CDMA using noncoherent M-ary orthogonal modulation over multipath Rayleigh fading channels. 'Errors-and-erasures' RS decoding is considered, where erasures are declared based on various erasure insertion schemes, such as the maximum output threshold test (OTT), ratio threshold test (RTT) and the joint maximum output and ratio threshold test (MOR-TT). Furthermore, the performance of 'errors-and-erasures' decoding employing the joint MOR-TT is compared to that of 'error-correction-only' decoding and to that of 'errors-and-erasures' decoding using the OTT as well as the RTT. The numerical results show that, when using 'errors-and-erasures' decoding, RS codes of a given code rate can achieve a significantly higher coding gain than without erasure information, and that the MOR-TT technique outperforms both the RTT and the OTT techniques.","PeriodicalId":205662,"journal":{"name":"EUROCON'2001. International Conference on Trends in Communications. Technical Program, Proceedings (Cat. No.01EX439)","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133125687","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 : 2001-07-04DOI: 10.1109/EURCON.2001.938163
Peiyu He, P. Sommen, B. Yin
A real-time blind signal separation experimental system has been designed and implemented using TMS320C40 DSP and LabVIEW virtual instruments software. The system is based on a new simplified mixing model that we proposed recently. The simplified model uses the fact that the acoustic transfer functions from a single source to two closely spaced (approximately several 10 cm apart from each other) microphones are very similar. Only the difference between these two transfer functions is needed. The main function of this DSP system is using the measured difference between two impulse responses (DIR) from one source to two microphones to realize the real-time blind signal separation. The real-time experimental results have shown that the proposed simplified mixing model is feasible. In particular, the blind separation performance can be improved considerably by introducing a time delay to solve the inverse problem of a non-minimum phase transfer function.
{"title":"A real-time DSP blind signal separation experimental system based on a new simplified mixing model","authors":"Peiyu He, P. Sommen, B. Yin","doi":"10.1109/EURCON.2001.938163","DOIUrl":"https://doi.org/10.1109/EURCON.2001.938163","url":null,"abstract":"A real-time blind signal separation experimental system has been designed and implemented using TMS320C40 DSP and LabVIEW virtual instruments software. The system is based on a new simplified mixing model that we proposed recently. The simplified model uses the fact that the acoustic transfer functions from a single source to two closely spaced (approximately several 10 cm apart from each other) microphones are very similar. Only the difference between these two transfer functions is needed. The main function of this DSP system is using the measured difference between two impulse responses (DIR) from one source to two microphones to realize the real-time blind signal separation. The real-time experimental results have shown that the proposed simplified mixing model is feasible. In particular, the blind separation performance can be improved considerably by introducing a time delay to solve the inverse problem of a non-minimum phase transfer function.","PeriodicalId":205662,"journal":{"name":"EUROCON'2001. International Conference on Trends in Communications. Technical Program, Proceedings (Cat. No.01EX439)","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128996261","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 : 2001-07-04DOI: 10.1109/EURCON.2001.938124
V. Kvicera
TESTCOM is engaged in an experimental propagation research in the frequency bands over 10 GHz. The research is especially focused on attenuation due to hydrometeors on line-of-sight paths. The aim of our research is to obtain long-term radio and radio meteorological data in our climatic conditions and to use them for proposals of cumulative distributions of attenuation due to hydrometeors for the average year and the average worst month. These distributions are applied to the calculations of quality and reliability of terrestrial fixed systems.
{"title":"Millimetre wave utilisation and propagation research in the Czech Republic","authors":"V. Kvicera","doi":"10.1109/EURCON.2001.938124","DOIUrl":"https://doi.org/10.1109/EURCON.2001.938124","url":null,"abstract":"TESTCOM is engaged in an experimental propagation research in the frequency bands over 10 GHz. The research is especially focused on attenuation due to hydrometeors on line-of-sight paths. The aim of our research is to obtain long-term radio and radio meteorological data in our climatic conditions and to use them for proposals of cumulative distributions of attenuation due to hydrometeors for the average year and the average worst month. These distributions are applied to the calculations of quality and reliability of terrestrial fixed systems.","PeriodicalId":205662,"journal":{"name":"EUROCON'2001. International Conference on Trends in Communications. Technical Program, Proceedings (Cat. No.01EX439)","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122561900","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 : 2001-07-04DOI: 10.1109/EURCON.2001.937794
Liu Hu, Z. Jing, L. Bo
In a DCSK (differential chaos shift keying) system implemented with noise suppression, there are three sources of variance: the DCSK signal itself, additive channel noise and the noise suppression scheme. In this paper, a novel DCSK scheme with chaotic polyphase sequence (CPS) is presented to avoid the variance of the DCSK signal itself and decrease the variance for additive channel noise. The simulation results show that the noise performance of the novel DCSK system is slightly degraded in contrast to FM-DCSK for the estimation variance of the noise suppression scheme. However, this design can be implemented easily.
{"title":"A novel design for DCSK communication system","authors":"Liu Hu, Z. Jing, L. Bo","doi":"10.1109/EURCON.2001.937794","DOIUrl":"https://doi.org/10.1109/EURCON.2001.937794","url":null,"abstract":"In a DCSK (differential chaos shift keying) system implemented with noise suppression, there are three sources of variance: the DCSK signal itself, additive channel noise and the noise suppression scheme. In this paper, a novel DCSK scheme with chaotic polyphase sequence (CPS) is presented to avoid the variance of the DCSK signal itself and decrease the variance for additive channel noise. The simulation results show that the noise performance of the novel DCSK system is slightly degraded in contrast to FM-DCSK for the estimation variance of the noise suppression scheme. However, this design can be implemented easily.","PeriodicalId":205662,"journal":{"name":"EUROCON'2001. International Conference on Trends in Communications. Technical Program, Proceedings (Cat. No.01EX439)","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116909424","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 : 2001-07-04DOI: 10.1109/EURCON.2001.938107
M. Rosić, V. Glavinic, S. Stankov
Distance learning systems (DLSs) are a class of important services that information infrastructures have to provide users. DLSs base their operation on information access, electronic transaction and communication services furnished by information infrastructures. Regarding the teaching process, by using DLSs new paradigms enable users to distribute educational content to support interaction among user classes (instructor-student, student-student and student-educational institution), testing, evaluation, and eventually advice in different domain knowledge areas. Classification of DLSs depends on the way these paradigms are implemented. In this paper, we concentrate on a particular DLS class, which encompass systems based on enabling Web access to otherwise classical intelligent tutoring systems-Web oriented intelligent tutoring systems. In this paper we present one such system-distributed tutor-expert system (DTEx-Sys), which has been developed for asynchronous distance educational purposes. DTEx-Sys is designed as a 3-tier client-server architecture where the intelligent tutoring functions are separated from the user interface and the knowledge base(s). The system functionality comprehends knowledge base access for arbitrary domain knowledge, along with testing, diagnosing and evaluation of students' work.
{"title":"DTEx-Sys-a Web oriented intelligent tutoring system","authors":"M. Rosić, V. Glavinic, S. Stankov","doi":"10.1109/EURCON.2001.938107","DOIUrl":"https://doi.org/10.1109/EURCON.2001.938107","url":null,"abstract":"Distance learning systems (DLSs) are a class of important services that information infrastructures have to provide users. DLSs base their operation on information access, electronic transaction and communication services furnished by information infrastructures. Regarding the teaching process, by using DLSs new paradigms enable users to distribute educational content to support interaction among user classes (instructor-student, student-student and student-educational institution), testing, evaluation, and eventually advice in different domain knowledge areas. Classification of DLSs depends on the way these paradigms are implemented. In this paper, we concentrate on a particular DLS class, which encompass systems based on enabling Web access to otherwise classical intelligent tutoring systems-Web oriented intelligent tutoring systems. In this paper we present one such system-distributed tutor-expert system (DTEx-Sys), which has been developed for asynchronous distance educational purposes. DTEx-Sys is designed as a 3-tier client-server architecture where the intelligent tutoring functions are separated from the user interface and the knowledge base(s). The system functionality comprehends knowledge base access for arbitrary domain knowledge, along with testing, diagnosing and evaluation of students' work.","PeriodicalId":205662,"journal":{"name":"EUROCON'2001. International Conference on Trends in Communications. Technical Program, Proceedings (Cat. No.01EX439)","volume":"19 10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126240817","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 : 2001-07-04DOI: 10.1109/EURCON.2001.937797
B. Vlaovič, Z. Brezočnik
This paper describes methods used to place telephone calls over packet-based networks with emphasis on Internet point-to-point communication. Two approaches will be described-H.323 and SIP (session initiation protocol). The first is an ITU standard and is already widely deployed by commercial vendors. The second, SIP, was developed by IETF activists and represents an "Internet approach" to telephony. First, a brief overview of reasons for the growing importance of IP telephony is given. It is followed by a short introduction to voice transmission over packet networks and an overview of the existing standards. In the second part of the paper, short examples of H.323 and SIP call setup are given.
{"title":"Packet based telephony","authors":"B. Vlaovič, Z. Brezočnik","doi":"10.1109/EURCON.2001.937797","DOIUrl":"https://doi.org/10.1109/EURCON.2001.937797","url":null,"abstract":"This paper describes methods used to place telephone calls over packet-based networks with emphasis on Internet point-to-point communication. Two approaches will be described-H.323 and SIP (session initiation protocol). The first is an ITU standard and is already widely deployed by commercial vendors. The second, SIP, was developed by IETF activists and represents an \"Internet approach\" to telephony. First, a brief overview of reasons for the growing importance of IP telephony is given. It is followed by a short introduction to voice transmission over packet networks and an overview of the existing standards. In the second part of the paper, short examples of H.323 and SIP call setup are given.","PeriodicalId":205662,"journal":{"name":"EUROCON'2001. International Conference on Trends in Communications. Technical Program, Proceedings (Cat. No.01EX439)","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122805777","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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