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Internet, 2005.The First IEEE and IFIP International Conference in Central Asia on

Date 26-29 Sept. 2005

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Displaying Results 1 - 25 of 38
  • A comparative analysis of routing protocols in GMPLS

    Publication Year: 2005
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (176 KB) |  | HTML iconHTML  

    Generalized multi-protocol label switching (GMPLS) which is also referred as multiprotocol lambda switching, supports devices that not only perform packet switching but also the devices that perform switching in domains of time, wavelength and space. This document provides the comparative analysis of the routing protocols involved in GMPLS networks. Open shortest path first (OSPF) and intermediate system to intermediate system (IS-IS) are the routing protocols being used in GMPLS for intra domain communications. We compare these protocols in terms of their basic features, traffic engineering (TE) extensions and enhancements provided in these protocols for support of GMPLS. View full abstract»

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  • Analysis of CPM and FWM phenomena for various signaling formats in 16 channel DWDM

    Publication Year: 2005
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1560 KB) |  | HTML iconHTML  

    CPM and FWM are significant nonlinear optical effects in DWDM systems. CPM leads to spectral broadening which may cause severe pulse distortion. While FWM is a nonlinear interaction that can occur between several channels of different wavelengths. FWM may result in significant crosstalk among the channels in DWDM systems. Understanding fiber nonlinearities is crucial in order to optimize system performance. The effects of CPM and FWM in conjunction with various signaling formats in 16 channel systems are evaluated. View full abstract»

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  • An integrated multilayer traffic engineering scheme in the new generation GMPLS based optical Internet

    Publication Year: 2005
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2744 KB) |  | HTML iconHTML  

    This paper proposes a new scheme for multi-layer traffic engineering (MTE) in generalized multi-protocol label switching (GMPLS) IP over optical networks. The scheme routes IP traffic guaranteeing sufficient bandwidth, high transmission quality and low resource usage. The routing decision is made via a cost metric which considers lightpath's power penalty and propagation delay and number of available wavelengths and transmitters. The requests are accommodated on mixed (lambda and packet) GMPLS label switched paths (LSPs) installed by nested RSVP-TE sessions. Extensive simulations demonstrate the good quality of the scheme's performance in terms of blocking probability and resource usage. View full abstract»

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  • Adaptive Lattice-Hammerstein RLS algorithm for wireless nonlinear equalizers

    Publication Year: 2005
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2736 KB) |  | HTML iconHTML  

    In this paper, the adaptive Recursive Least-Squares algorithm is derived for the Lattice-Hammerstein filter leading to the proposed RLS Lattice-Hammerstein nonlinear adaptive filter. The performance of the proposed algorithm is compared to both SG Lattice-Hammerstein and LMS Transversal-Hammerstein algorithms in a nonlinear channel modeling scenario. It is shown that the convergence rate of the RLS Lattice-Hammerstein algorithm is much higher than the other two with a lower steady-state error. Simplicity of the Hammerstein structure compared to the Volterra expression makes is more appropriate for modeling and equalizing nonlinear channels. View full abstract»

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  • Transmultiplexer integer-to-integer filter banks

    Publication Year: 2005
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1976 KB) |  | HTML iconHTML  

    Transmultiplexers equipped with integer-to-integer filters can be applied for transmitting coded signals or computer data. The new method of transmultiplexer filter design is presented. View full abstract»

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  • An intrusion detection system based on system call

    Publication Year: 2005
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1632 KB) |  | HTML iconHTML  

    Intrusion detection is an efficient way to protect information system. This paper puts forward a new method of anomalous intrusion detection based on system call. It uses system calls regarded as input, and creates a FSA (finite-state automation machine) for the functions in the program. Then the FSA is used to detect the attack. Moreover, it can find the place of the vulnerability which exists in the program. This can help to alter the source program. Results are shown that this method is effective for some intrusion events. View full abstract»

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  • Estimation of the impact of electromagnetic and co-channel interference on the Bluetooth receiver

    Publication Year: 2005
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (229 KB) |  | HTML iconHTML  

    A major issue to be addressed in the design, operation and applications of Bluetooth system is interference. This paper presents the results of interferences study investigating the impact of electromagnetic interference (EMI) and co-channel interference on Bluetooth receiver. Results are based on simulations by means of different scenarios. Preliminary results show that the performance of Bluetooth will be degraded in presence of interferences, being necessary to design a more robust Bluetooth receiver View full abstract»

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  • An efficient wavelet/neural networks-based face detection algorithm

    Publication Year: 2005
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (6848 KB) |  | HTML iconHTML  

    In this paper, we proposed an efficient method to address the problem of face detection that is based on neural networks (NNs) and wavelet representation. We utilized a multilayer perceptron (MLP) so as to classify skin and non-skin pixels in the YCrCb color space. In this work, skin samples in images with varying lighting conditions are used to obtain a wide skin color distribution. The training data is generated from positive and negative training patterns in the Cb-Cr planes. Subsequently, training set is fed to an MLP, trained using the Levenberg-Marquardt algorithm using these skin samples. We apply the above mentioned NN-based skin classifier to the chrominance values corresponding to the coarsest level of the chrominance approximation subimages obtained from wavelet transform to classify the candidate face pixels. Furthermore, we have proposed a subspace approach in the space-frequency domain for the fast detection of face utilizing wavelet representation. View full abstract»

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  • A power reduction technique based on the microscopic dynamic voltage scaling (DVS) of multimedia processors in wireless communication terminal

    Publication Year: 2005
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (214 KB) |  | HTML iconHTML  

    The paper proposes a DVS method, which effectively reduces the power consumption of multimedia signal processor. Analytical expressions for effective range of power saving efficiency obtained with the assumption of a Gaussian distribution for the frame-based computational burden of the multimedia processor are derived. A closed form solution for the power saving factor is obtained in terms of the mean and standard deviation of the distribution. An MPEG-2 audio/video decoder algorithm is tested on Xscale processor for experimental verification of the power saving due to the proposed DVS approach. The experimental results with diverse MPEG-2 audio/video files show about 35% power saving efficiency View full abstract»

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  • A CAN-based P2P infrastructure for semantic Web services publishing and discovery

    Publication Year: 2005
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (256 KB) |  | HTML iconHTML  

    After merger of Web services and semantic Web, semantic Web services (SWS) has received much attention from researchers due to its ability of automatic Web service publishing, discovery, execution and composition. Currently Web service systems, which publish WSDL-described Web services in UDDIs, cannot support SWS and UDDI has become the bottleneck of the whole system and would cause single node failure problems. Therefore, we propose a CAN-based P2P system to replace traditional UDDI, by distributing the functions of the UDDI among all the peers in the P2P network. At the same time, we design an ontology-based mechanism, guaranteeing every service would be registered on a specific peer in the CAN-based P2P network, according to the service's ontology. By replacing the UDDI, our system improves the scalability and stability of the SWS system, and realizes an efficient ontology-based publishing and discovery of semantic Web services. View full abstract»

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  • Channel estimation for OFDM systems using superimposed training

    Publication Year: 2005
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1824 KB) |  | HTML iconHTML  

    Superimposed training has raised lots of attentions due to its great spectral efficiency and its relatively fast channel estimation algorithms. In this paper, we present channel estimation methods for OFDM system using periodic superimposed training added in frequency domain. At the receiver, channel estimation is done both in time domain (pre-FFT) and frequency domain (post-FFT). In addition, we prove that the estimation is MMSE solution. Simulations show that those methods are effective especially when SNR is lower. View full abstract»

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  • An anycast-based P2P routing protocol for mobile ad hoc networks

    Publication Year: 2005
    Cited by:  Papers (2)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4470 KB) |  | HTML iconHTML  

    With the increasing popularity of mobile ad-hoc networks (MANETs), it becomes a challenge to integrate peer-to-peer (P2P) technique into MANETs efficiently. This paper proposes to integrate anycast routing technique to mobile P2P networks to reduce overhead and optimize query lookup service. We propose a novel anycast-based mobile P2P routing protocol for MANETs, called AMPP, which integrates Chord and anycast routing protocol at the network layer in highly dynamic MANETs. Our simulation results show that integrating anycast routing technique to mobile P2P network can reduce query lookup cost and improve network performance View full abstract»

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  • Performance analysis of a finite word length implemented CCK modem with rake receiver for WLAN system

    Publication Year: 2005
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4360 KB) |  | HTML iconHTML  

    In this paper, the effect of finite signal word lengths on the bit error rate (BER) performance of complementary code keying (CCK) modem in additive white Gaussian noise (AWGN) and Rayleigh fading channels is investigated. The 2-bit, 4-bit, 6-bit and 8-bit word lengths are considered for their performance comparison. The performance results are also compared to that of a floating-point implementation. These performances has been evaluated through simulation studies and validated by theoretical analysis. View full abstract»

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  • Performance evaluation of various data detection algorithms in the downlink of TD-SCDMA systems with smart antennas

    Publication Year: 2005
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2968 KB) |  | HTML iconHTML  

    Firstly a downlink transmission model which includes smart antennas is developed. Based on this model, the TD-SCDMA downlink transmission beamforming methods, in consideration of a mobile terminal using various data detection algorithms (joint detection, single detection), are discussed respectively. Three beamforming methods have been evaluated and two of them have been modified in order to make them available for the TD-SCDMA systems. Furthermore, the data detection methods have been investigated under the influence of these beamforming methods. View full abstract»

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  • A framework for end-to-end differentiated services QoS context transfer in mobile IPv6

    Publication Year: 2005
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4128 KB) |  | HTML iconHTML  

    Future 4G mobile communication networks are expected to provide all IP-based services. Providing QoS guarantees and mobility support has become a hot research topic in the scenario. Differentiated Services (DiffServ/DS) is a promising QoS support approach due to its scalability. However, it faces a lot of challenges in mobile environments, such as no signaling mechanism to negotiate dynamically the Service Level Specification (SLS), traffic flow identification, etc. The COPS-SLS protocol is used as a signaling mechanism to achieve end-to-end inter-domain SLS dynamic negotiation and a framework for end-to-end DiffServ context transfer in Mobile IPv6 is proposed to overcome the weakness of context transfer protocol which can not meet the need of end-to-end QoS mechanisms because contexts are only transferred between ARs. Moreover, using the context transfer to re-establish DiffServ context can avoid re-initiating COPS-SLS signaling from scratch, and the end-to-end DiffServ context only transfers to the new added QBs along new path after the MN performs handover in this paper. Hence, our scheme can minimize the handover service disruption, and enable real-time session to promptly get the same forwarding process during the MN performs handover. View full abstract»

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  • Identifying local trust value with neural network in P2P environment

    Publication Year: 2005
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (183 KB) |  | HTML iconHTML  

    Global trust value of P2P (peer-to-peer) has been studied in detail, but the base of it, local trust value, has not been explored in depth. The existent models only adopt simple methods to calculate it. These methods are based on count of success and failure times of transaction, so it cannot represent the distribution of success and failure in transaction history. It is the first time to introduce neural network to identify the local trust value in P2P environment. Transaction result sequence that can represent the transaction history is used as input of neural network to identify local trust value. The structure of neural network, method of input standardization and training sample constructing are presented. Analysis and experiment show that it is feasible and effective to identify local trust value with neural network in P2P environment View full abstract»

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  • Assessment of VoIP quality over access networks

    Publication Year: 2005
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (373 KB) |  | HTML iconHTML  

    This paper assesses VoIP quality over access networks in Pakistan using a delay jitter measurement methodology for evaluating the perceptual quality of voice calls using the ITU-T G.107 speech quality E-model. Passive measurements for voice calls in the presence of background Internet data traffic for G.723.1 and G.729a codecs are carried out using a non-intrusive parametric model. The R-factor and resultant Mean Opinion Scores (MOS) were calculated at different link loads and congestion hot spots were identified. The study highlights the inadequacy of access networks for handling VoIP traffic at current in Pakistan and suggests alleviating congestion by increasing capacity in access networks View full abstract»

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  • Focus on next generation Internet

    Publication Year: 2005
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1120 KB) |  | HTML iconHTML  

    The term next generation Internet (NGI) is increasingly common. Almost every system application protocol and product has a next-generation version. In this paper the fundamental concept of NGI is illustrated and the current situation of the development of NGI in China is comprehensively discussed. The viewpoints on the network framework, communication technology, and protocol and security strategy of NGI are put forward. View full abstract»

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  • OFDMA uplink ranging for IEEE 802.16e using modified generalized chirp-like polyphase sequences

    Publication Year: 2005
    Cited by:  Papers (5)  |  Patents (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3711 KB)  

    For uplink synchronization, IEEE 802.16e wireless metropolitan area networks group has suggested ranging for OFDMA based uplink system. However, it is inherently vulnerable to the channel selectivity and other users' interferences at low SNR. In this paper, a novel detection scheme for OFDMA ranging has been proposed using modified generalized chirp-like (GCL) sequences to cope with these drawbacks. Modifying GCL sequences, hybrid detection scheme which simultaneously carrying out non-coherent and differential detection can be achieved. The ranging performance has been considerably enhanced with this algorithm. Simulation results show that the proposed scheme is applicable to -3 dB with the mobility up to 50 km/h View full abstract»

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  • Application of cdma2000 in Wireless Local Loop (WLL)

    Publication Year: 2005
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (192 KB) |  | HTML iconHTML  

    In this paper, we examine WLL capacities for voice and voice plus data traffic with cdmaOne and cdma2000 technologies. We found that the capacity of a WLL using smart antenna with cdma2000 is much higher than the cdmaOne. Therefore, it would be cost effective for a WLL to use cdma2000 with smart antenna to provide voice, voice plus data services. View full abstract»

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  • Comparative study of several new channel path decision methods in TD-SCDMA system

    Publication Year: 2005
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (304 KB) |  | HTML iconHTML  

    In TD-SCDMA system, a special training sequence, midamble, is exploited for channel estimation. The performance of conventional B. Steiner channel estimator is affected by the additive white Gaussian noise in the channel. This paper proposes several effective additional processing steps to decide the multi-path delays' positions. Hence, most of the effects brought by the additive noise are avoided and the performance of the system is improved accordingly. The performance based on the new channel path decision methods are simulated in various channel conditions. Comparisons and analyses are also given. View full abstract»

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  • Comparison of OFDM with CDMA system in wireless telecommunication for multipath delay spread

    Publication Year: 2005
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (392 KB) |  | HTML iconHTML  

    Orthogonal frequency division multiplexing (OFDM) is a parallel transmission scheme, where a high-rate serial data stream is split up into a set of low-rate sub streams, each of which is modulated on a separate subcarrier. Increasing the number of parallel transmission reduces the data rate that each individual carrier must convey and that lengthens the symbol period. This is extremely useful in environments where multipath fading is high. Most third generation mobile phone systems are using code division multiple access (CDMA) as their modulation technique. Hence, this paper compares the performance of OFDM with that of CDMA. The analysis of bit error rate (BER) performance suggests, OFDM is clearly better than CDMA. This performance is analyzed against extreme multipath delay spread conditions and with same number of users and total data transmitted. The channel effects are also same for both systems. View full abstract»

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  • On the efficiency of the MI-MAC protocol for multimedia traffic integrated access over wireless networks

    Publication Year: 2005
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2080 KB) |  | HTML iconHTML  

    In this work, we study the efficiency of a new reservation medium access control protocol for wireless communications, named Multimedia Integration Multiple Access Control (MI-MAC), by comparing it with another well-known protocol for multimedia integration over wireless networks (DPRMA). Our scheme, one of the first in the literature that considers the integration of streams from latest technology video encoders with other types of packet traffic over wireless networks, is shown to outperform DPRMA* (a very slightly modified version of DPRMA, used in order to be able to make comparisons between the two protocols) in terms of aggregate channel throughput and mean Web data transmission delays. View full abstract»

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  • Grouping WI-MAX, 3G and WI-FI for wireless broadband

    Publication Year: 2005
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (5976 KB) |  | HTML iconHTML  

    Many advanced data services are driving up wireless technology, which is further boosted by growth in advanced market segments. The wireless industry is evolving from a Web of independent networks into a single integrated network with multiple standards; the expectation is that WI-FI, WI-MAX and 3G will coexist to enable a host of exerting new applications and business models. This paper focuses on concepts of WI-MAX technology, which employs microwave for the transfer of data wirelessly, and it also presents its comparison with WI-FI, and 3G technologies. WI-MAX is delivering broadband wireless access to the masses and represents alternative to digital subscriber lines (DSL) and cable broadband access. WI-MAX is based on IEEE 802.16 standard and is scalable. It stands for wireless (WI) microwave access (MAX). WI-MAX will provide anywhere, anytime connectivity. Features of WI-MAX are OFDM i.e. orthogonal frequency division multiplexing, sub channelization, directional antennas and adaptive modulation, which make WI-MAX as the technology of today. The Benefit of WI-MAX technology is that the signals can be run very close to each other on wireless channels. Super narrow lanes can put a lot of traffic over them without disturbance. Many technologies currently available can only provide line of sight (LOS) coverage; the technology behind WI-MAX has been optimized to provide excelled non-line of sight (NLOS) coverage. View full abstract»

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  • An approach to fault-tolerant mobile agent execution in distributed systems

    Publication Year: 2005
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (5200 KB) |  | HTML iconHTML  

    Mobile agents are no longer a theoretical issue since different architectures for their realization have been proposed. With the increasing market of electronic commerce it becomes an interesting aspect to use autonomous mobile agents for electronic business transactions. Being involved in money transactions, supplementary security features for mobile agent systems have to he ensured. Fault-tolerance is fundamental to the further development of mobile agent applications. In the context of mobile agents, fault-tolerance prevents a partial or complete loss of the agent, i.e., ensures that the agent arrives at its destination. Simple approaches such as checkpointing are prone to blocking. Replication can in principle improve solutions based on checkpointing. However, existing solutions in this context either assume a perfect failure detection mechanism (which is not realistic in an environment such as the Internet), or rely on complex solutions based on leader election and distributed transactions, where only a subset of solutions prevents blocking .This paper proposes a novel approach to fault-tolerant mobile agent execution, which is based on modeling agent execution as a sequence of agreement problems. Each agreement problem is one instance of the well-understood consensus problem. Our solution does not require a perfect failure detection mechanism, while preventing blocking and ensuring that the agent is executed exactly once. View full abstract»

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