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Electrical and Computer Engineering, 2002. IEEE CCECE 2002. Canadian Conference on

Date 12-15 May 2002

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  • IEEE CCECE2002 Canadian Conference on Electrical and Computer Engineering [front matter]

    Page(s): 0_1 - S_45
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  • Author index

    Page(s): 6_1 - 6_12
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  • Keyword Index

    Page(s): 7_1 - 7_12
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  • AM-SRL: Adaptive Multicast operation of the Supernode-based Reverse Labeling algorithm

    Page(s): 1412 - 1417 vol.3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (474 KB) |  | HTML iconHTML  

    In this paper, the supernode-based reverse labeling (SRL), a quality of service (QoS) routing algorithm for mobile ad hoc networks (MANET), is extended to provide adaptive multicast service. The algorithm, termed AM-SRL (Adaptive Multicast operation of Supernode-based Reverse Labeling), adaptively builds an on-demand multicast mesh by exploiting the hierarchical structure of SRL. The virtual route discovery process of SRL functions as multicast member distribution awareness agent in AM-SRL and the reverse route establishment algorithm enables the adaptive generation of the multicast mesh. AM-SRL guides the redundant level of the multicast mesh by introducing a partial mesh factor. The adaptivity of virtual route selection, reverse route establishment and mesh formation make the algorithm efficient, robust and reliable. View full abstract»

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  • Cytobots: intracellular robotic micromanipulators

    Page(s): 1640 - 1645 vol.3
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    A cytobot is an intracellular robotic micromanipulator, a microfabricated device small enough to be introduced into a cell. Control for a cytobot can be accomplished using three mutually perpendicular sequential magnetic control systems along with an electromechanical stepper microscope stage. Control depends on viscous damping within the cell. The design and fabrication techniques are discussed and the processing techniques used in the fabrication of cytobots highlighted. Fabrication of various magnetic cytobots are then illustrated namely, a chisel, a "circular" saw blade, a "fishing" hook; a cuff for fibers, a box to confine an organelle, and an aspirator, and the functionality of these devices is explained. In order for the cytobot to get into the cell, it must be injected with a small needle, or since the majority of the structure is a magnet, it could be fired in ballisticly like a magnetic bullet. Once introduced into an embryonic cell one can continuously manipulate one cell of the developing organism as cell division proceeds. We also discuss the possibility of making such devices small enough to enter the cell nucleus, i.e., karyobots. View full abstract»

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  • Optimal radioport placement in cellular networks

    Page(s): 1321 - 1324 vol.3
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    The trend in cellular networks is toward smaller cell sizes in order to achieve a larger capacity and to reduce the transmit power of wireless handsets. This increases the number of radioports and therefore it increases the infra-structure cost of the network. Optimal placement of radioports can yield significant savings. This paper proposes two algorithms for placement of radioports in order to minimize the maximum path loss experienced by wireless handsets. The first algorithm is a local heuristic search method based on the Sebestyen (1966) algorithm. The second is a hybrid of the genetic and K-means algorithms. Simulation results show that for small floor plans there is placement error in all Sebestyen solutions. However, most solutions produced by the hybrid algorithm are global optimums and the algorithm is two orders of magnitude more efficient than an exhaustive search. View full abstract»

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  • A middleware based approach for designing routing protocols

    Page(s): 1436 - 1441 vol.3
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    The design and architecting for new routing protocols is an expensive task; either in time-consumption or costs. Routing protocols are complex systems; they manage distributed network state (sometimes the whole network), in order to create and maintain the routing databases. Existing routing protocol implementations are compact, bundling together a database, a (optimal) path calculation algorithm and a network state distribution mechanism. This paper presents a middleware-based approach for designing and managing the routing protocols. The approach analyzes the protocol functionality based on the idea of decomposing routing protocols into fundamental building blocks and identifying the role of each component, Finally, the paper proposes a framework on how new routing protocols could be dynamically composed from a hierarchy of basic classes. For implementation we used the distributed object platform OMG's CORBA. View full abstract»

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  • In-building data-over-voice Internet access

    Page(s): 1418 - 1423 vol.3
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    High speed Internet access is becoming an essential service in the workplace which often includes hotels. This paper investigates short-range Internet access methods suitable for hotels, hospitals, and historic office buildings where pervasive telephone service exists and there is a need for "always on" high speed Internet access. It is desirable to avoid the costly installation of new wires to provide this service. While digital subscriber line technologies have matured over the last decade, and these are more than capable of providing the required service, their cost is excessive, and when transmission distances are very short there is an opportunity to apply lower-cost data-over-voice solutions. This paper evaluates the suitability of various baseband line coding techniques for data transmission in a simultaneous voice and data environment. Through computer simulation, a number of potential line coding methods were characterized by their power spectral density and eye diagram. These characterizations were used to evaluate data transmission capacity, error performance and potential interference with voice communication. The paper shows that bipolar-return to zero (BPRZ) and bipolar-non return to zero (BPNRZ) ternary coding provide the greatest potential improvement in data transmission rate while sacrificing the least in transmission performance. Quaternary and pentary methods are shown to be poor, and 2B1Q coding (widely used in ISDN and HDSL) is not applicable for data-over-voice since low frequency data transmission is required. View full abstract»

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  • Dynamic support of service differentiation in wireless networks

    Page(s): 1325 - 1330 vol.3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (506 KB) |  | HTML iconHTML  

    Wireless networks are becoming progressively the access technology of preference to the global Internet, while fast backbone wired networks (mostly optical IP based) will be transporting large volumes of aggregate traffic. This scenario is one of the main visions set for 4th generation wireless networks. However, in order for this vision to become reality, new features need to be introduced in the wireless networking infrastructure, one of the "key" ones being the ability to provide service differentiation. This is the subject of the present work. It addresses the issues of extending service differentiation to wireless communication systems enabling a network to effectively service delay and throughput sensitive applications. We propose a service differentiation capable network architecture. Our study investigates how different packet scheduling can be accommodated in wireless networks to provide service differentiation for several types of traffic. Our design considers the need for interoperability between wired and wireless world, the spectrum limitations and "error" prone behavior of the wireless channel. View full abstract»

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  • Performance evaluation of VBR traffic in InfiniBand

    Page(s): 1532 - 1537 vol.3
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    The InfiniBand architecture (IBA) is becoming an industry standard both for communication between processing nodes and I/O devices and for interprocessor communication. It replaces the traditional I/O bus with a switch-based interconnect for connecting processing nodes and I/O devices. It is being developed by the InfiniBandSM Trade Association (IBTA) to provide the levels of reliability, availability, performance, scalability, and quality of service (QoS) necessary for present and future server systems. For this, IBA provides a series of mechanisms that are able to guarantee QoS to the applications. Alfaro, Sanchez and Das (see Proceedings of International Parallel and Distributed Processing Symposium, April 2002) proposed a strategy to compute the InfiniBand arbitration tables. We only evaluated our proposal for CBR traffic with fixed mean bandwidth requirements. We evaluate our strategy to compute the InfiniBand arbitration tables with VBR traffic. Performance results show that, this class of traffic also gets their QoS requirements. View full abstract»

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  • Real-time video applications over ABR using FASTRAC-a rate control algorithm

    Page(s): 1565 - 1570 vol.3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (409 KB) |  | HTML iconHTML  

    The ATM ABR service category was initially designed to support non-real-time applications, e.g., data file transfer. However it is possible for ABR to support real-time applications (such as distributed multimedia applications) by taking advantage of the inherent traffic control capability of ABR and the adaptation ability of real-time applications. This paper consists of two parts. In the first part we review the principles of operation of the FASTRAC, an ABR control mechanism. This analysis allows us to better understand the adaptation ability of real-time applications, a feature deemed essential to take advantage of the inherent traffic control capability of ABR while guaranteeing a reasonable QoS required by the end application. In the second part we explore the use of ABR service to support real-time video transmission using FASTRAC. Our simulation results show that FASTRAC can support both real-time video applications and non real-time applications. View full abstract»

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  • Agent-based routing algorithms on a LAN

    Page(s): 1442 - 1447 vol.3
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    The AntNet algorithm for adaptive routing is implemented on a LAN using the TCP/IP protocol. A study is made of the relative merits of different reinforcement parameters central to the stable operation of the algorithm. The case of a constant reinforcement leads to slow but dependable performance whereas adaptive reinforcement appears to be sensitive to the window over which statistics are estimated. View full abstract»

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  • TSMLE-based MT-CDMA system in Rician fading channel

    Page(s): 1386 - 1391 vol.3
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    Bit error rate (BER) analysis for a two-stage maximum likelihood estimation (TSMLE) based multi-tone code division multiple access (MT-CDMA) system is presented in this paper. The analysis is presented for a slowly Rician fading and frequency selective channel in the indoor environment. A model for the computation of average bit error probability is derived for quadrature phase shift keying (QPSK) modulation. The influence of number of tones is studied for given bandwidth (BW), bit rate and transmission power. View full abstract»

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  • Communication receivers based on Markov models of the fading channel

    Page(s): 1255 - 1260 vol.3
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    The problem researched is the comparison of different finite-state Markov channel (FSMC) models used to approximate the Rayleigh fading channel. The criterion used to compare the Markov models is the error performance of receivers based on the FSMC, where the sufficient statistics are obtained from the Jakes-Clarke (1974) fading channel. The FSMC receivers perform joint maximum a posteriori (MAP) sequence detection and channel estimation using the Viterbi algorithm. Receiver outputs of bit decision and channel estimation error are used as the measure of comparison between various models and a well-developed reference receiver. For this research 1st and 2nd order models were implemented. Simulation results suggest that there can be a significant improvement in receiver performance when the receiver is based on a 2nd order model over a 1st order model. Likewise, an improvement in performance is observed when the number of Markov states is increased. View full abstract»

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  • A study of band-limited chip waveforms for asynchronous DS-CDMA systems

    Page(s): 1271 - 1275 vol.3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (364 KB) |  | HTML iconHTML  

    This paper investigates the effect of chip waveform shaping on multiple access interference (MAI) in band-limited direct sequence code-division multiple access (DS-CDAM) systems. In particular, it concentrates on the family of band-limited waveforms with zero interchip interference (ICI) and with arbitrary excess bandwidth β in the range 0 ≤ β ≤ 1. A criterion for the performance comparison of various band-limited chip waveforms based on the elementary density function is introduced. The comparison is made among different chip waveforms, including the optimal chip waveform, the square-root raised cosine proposed for 3G wireless systems and the previously proposed "better than Nyquist" pulse. Finally, the effect of varying the roll-off factor of a band-limited chip waveform on the MAI level is also investigated. View full abstract»

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  • Evolving and managing trust in grid computing systems

    Page(s): 1424 - 1429 vol.3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (453 KB) |  | HTML iconHTML  

    A grid computing system is a geographically distributed environment with autonomous domains that share resources amongst themselves. One primary goal of such a grid environment is to encourage domain-to-domain interactions and increase the confidence of domains to use or share resources: (a) without losing control over their own resources; and (b) ensuring confidentiality for others. To achieve this, the "trust" notion needs to be addressed so that trustworthiness makes such geographically distributed systems become more attractive and reliable for day-to-day use. In this paper we view trust in two steps: (a) verifying the identity of an entity and what that identity is authorized to do; and (b) monitoring and managing the behavior of the entity and building a trust level based on that behavior The identity trust has been the focus of many researchers, but unfortunately the behavior trust has not attracted much attention. We present a formal definition of behavior trust and reputation and discuss a behavior trust management architecture that models the process of evolving and managing of behavior trust in grid computing systems. View full abstract»

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  • Performance analysis of multimedia applications in Differentiated Services networks

    Page(s): 1594 - 1599 vol.3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (469 KB) |  | HTML iconHTML  

    In this paper, we present simulation results assessing the performance of DiffServ-capable networks supporting real time multimedia traffic. We evaluate the performance of voice traffic, H263 video traffic and distributed interactive virtual environments (DIVE) applications with Web background traffic in a DiffServ-capable network. Particularly, the performance of weighted fair queuing (WFQ) algorithm is studied, and a realistic Web workload model generating aggregation of self-similar bursty traffic flows is developed and used to evaluate the performance of all above multimedia applications. Our analysis demonstrates that these multimedia applications can be well supported by DiffServ-capable networks even under the bursty Web style traffic, given that the subscribed bandwidth of the application is no less than its source generating data rate. According to our results, even for the most demanding DIVE application, bandwidth reservation at twice the source-generating rate is enough. View full abstract»

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  • A measure of fairness of service for scheduling algorithms in multiuser systems

    Page(s): 1583 - 1588 vol.3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (430 KB) |  | HTML iconHTML  

    When considering issues of fairness of scheduling algorithms for packet data in networks, there is no well-defined quantitative value for the "fairness" of the system. Rather, fairness is usually expressed in broader terms. Generally, a system is deemed to be fair if it meets certain criteria on throughput or delay, and unfair if the criteria are not met. For example, a system in which some user receives a throughput less than Xbits/sec or experiences a delay τ with probability greater than p% may be deemed to be unfair. These definitions of fairness say if the system is or is not fair, but not how fair or unfair. This paper attempts to make a quantitative definition for a value of "fairness" that makes sense from both a mathematical and semantic standpoint. Such a value could be used to quickly compare the fairness of differing systems or algorithms. Definitions for the self-fairness and self-unfairness of the users of the system, and the average fairness and average unfairness of the overall system are proposed. The case is first considered when all users are weighted equally. That is, every user is considered to have the same importance, and hence each user should receive an equal proportion of the allocated resources for the system to be fair. The definitions are then extended to the case when the users have different weightings (for example, to achieve different levels of quality of service). The definitions take the viewpoint that the users themselves control what resources they are allocated. However, the definitions can just as easily be applied to the case when a central scheduling algorithm determines the allocation of resources to the users. View full abstract»

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  • Fault detection in electro-hydraulic servo-positioning systems using sequential test of Wald

    Page(s): 1628 - 1633 vol.3
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    Presents a scheme for fault detection in hydraulic servo positioning systems using analytical redundancy. A fault is understood as a malfunction in the dynamic system that leads to an unacceptable anomaly in the overall system's performance. The approach taken is to first construct a nonlinear observer. The actuator's linear velocity is taken as input to the observer. The cumulative sum of the residuals, taken from the difference between the actual and the observed velocities, is then used in a sequential test of Wald to determine the occurrence of a fault. Experiments are conducted for faults due to incorrect supply pressures as well as sensor faults. Results show the efficacy and the promise of the proposed scheme. View full abstract»

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  • Dynamic resource allocation in QoS-enabled/MPLS supported virtual private networks and its Linux based implementation

    Page(s): 1448 - 1454 vol.3
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    This paper describes a proposal for the support of quality of service over virtual private networks (VPN). We combine DiffServ, MPLS and a dynamic resource allocation technique in order to provide a QoS-enabled VPN. We apply dynamic resource allocation using traffic predictors. Our predictor assumes that the statistical behavior of aggregate traffic streams is statistically described through α-stable long-range dependent stochastic processes. This is a valid assumption, since some of the authors of this work proved in the past that such distributions more accurately describe aggregate traffic passing through modern networks as compared to earlier models. In our work, we investigate a scenario in which the service provider establishes service level agreements (SLA) with the customers, where the resources and QoS requirements are defined. When operating the network, the provider uses dynamic resource allocation algorithms to pace and forward traffic while optimizing the resource utilization. The conceptual architecture of this technology is provided along with a description of our Linux-based experimental testbed. We also discuss some important performance considerations obtained through extensive computer simulations. View full abstract»

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  • A fast CPU conserving algorithm for optimal broadcast scheduling in networks of pervasive devices

    Page(s): 1392 - 1399 vol.3
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    The search for optimal broadcast scheduling scheme (Soptimal), in a hybrid unicast-broadcast system with users of realistic-impatient behavioral patterns, is shown to be a rather complex, nonlinear inequality-constrained optimization problem. By exploiting some mathematical properties of the main cost function, we prove that the given optimization problem can be considerably simplified. Based on this simplification, first we derive a closed form approximate expression for Soptimal and, consequently, we propose an algorithm for fast CPU conserving estimation of Soptimal. Experimental results verify that the proposed algorithm requires minimum computation, while providing performance almost identical to Soptimal obtained through numerical estimation. The given algorithm is shown to have a direct applicability in the area of pervasive computing, one example being Service Discovery Service (SDS) or node discovery in ad hoc networks. View full abstract»

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  • Communicating over white Gaussian interference networks with feedback

    Page(s): 1261 - 1264 vol.3
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    White Gaussian interference networks with K messages, T transmitters and R receivers are considered. The messages are transmitted through the network in a point-to-point manner, i.e., each message is encoded by exactly one transmitter and is destined for exactly one receiver. It is further assumed that feedback is available so that each transmitter sees the outputs of the receivers to which it is sending messages. Communication strategies are developed that perform well for such networks. For multiple-access channels (K = T, R = 1) with equal transmitter powers the strategies achieve the sum-rate capacity if the powers are beyond some threshold. For interference channels (K = T = R) numerical results show that the strategies can significantly enlarge the no-feedback capacity region. View full abstract»

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  • Performance improvement of prioritized handoff schemes in multi-service mobile cellular systems

    Page(s): 1347 - 1351 vol.3
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    With the rapid growth in the demand for mobile communications, many works on intense handoff have been done to achieve more efficient use of the scarce spectrum allocated to mobile communication system. In this paper, a new tradeoff scheme based on dual-queue FIFO scheme to improve the system performance is given, which is combined with HCA (hybrid channel assignment) algorithm. In comparison with the common FIFO queuing scheme and the improved FIFO queuing algorithm using the HCA scheme, our algorithm achieves a good tradeoff between performance and computational cost in multi-service mobile communication systems. View full abstract»

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  • The role of reconciliation in retrieving historical objects in a multi-version object-based system

    Page(s): 1482 - 1486 vol.3
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    Traditional multiversion database environments use data versioning for historical purposes as well as for issues related to transaction management. Multiversioning can increase concurrency and can be used to execute queries against historical records. This paper shows how this technique can be applied in a multiversion object-based environment. View full abstract»

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  • Consideration and research issues for the future generation of mobile communication

    Page(s): 1276 - 1281 vol.3
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    With the explosive growth of the mobile communication and the expansion of Internet services, Mobile multimedia services, e.g. more than 2Mb/s, are expected for future mobile communication systems. As 3G is still not sufficient to support future mobile communication strategy and according to the historical indication of a generation revolution once a decade, it is high time to discuss the development of the future generation mobile communication systems. After illuminating the impetus force to driven the 4G research, this paper studies the vision and framework of 4G, describes the adaptability features of terminals, networks and applications in 4G system and proposes some technologies in the design of future mobile communication systems. View full abstract»

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