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Information, Communications and Signal Processing (ICICS) 2011 8th International Conference on

Date 13-16 Dec. 2011

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Displaying Results 1 - 25 of 238
  • [Front cover]

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  • Welcome message from general chairs

    Page(s): 4
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  • Welcome message from program chairs

    Page(s): 5
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  • Program at a glance

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  • Session listing

    Page(s): 13 - 29
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  • Author index

    Page(s): 114 - 120
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  • Feedback active noise control system and its application to MRI noise

    Page(s): 1 - 5
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (343 KB) |  | HTML iconHTML  

    In this paper, a novel feedback active noise control (ANC) system combining a linear prediction filter and its application to reducing noise generated from magnetic resonance imaging (MRI) devices (MRI noise) are introduced. The proposed ANC system can reduce narrowband noise while suppressing a disturbance with broadband components. Such a disturbance makes a conventional feedback ANC system unstable or divergent because the disturbance corrupts the input signal to the system. In the proposed ANC system, a linear prediction filter is combined with the feedback ANC system to suppress the disturbance. Moreover, a modified-error feedback ANC system that can update the noise control filter using an ordinary adaptive algorithm such as NLMS instead of the Filtered-x algorithm is also incorporated with the linear prediction filter. In the modified-error feedback ANC system, not only the stability but also the convergence rate and noise reduction ability can be improved. Simulation results demonstrate that the proposed feedback ANC systems are superior to conventional feedback ANC systems in terms of the stability, convergence rate, and noise reduction ability. Furthermore, the proposed ANC system is applied to reducing MRI noise. MRI noise consists of many sinusoidal waves whose amplitude varies with time. We found that the feedback ANC system can effectively reduce MRI noise. The proposed ANC system is implemented in a head-mounted structure to control the noise near the user's ears and to compensate for the low output of compact loudspeakers. Experimental results demonstrate that the proposed ANC system with head-mounted structure can significantly reduce MRI noise by approximately 30 dB in a high field in an actual MRI room even if the imaging mode changes frequently. View full abstract»

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  • Data-driven analysis of functional MRI time-series using a region-growing approach

    Page(s): 1 - 5
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (393 KB) |  | HTML iconHTML  

    We present a data-driven method to analyze functional magnetic resonance imaging (fMRI) time-series where multiple hypotheses are generated for inferential methods from the data itself without any assumptions on the time-series. The method does not require the number of clusters to be defined a priori. Activation detection is based on region growing which specifically suits the spatiotemporal characteristics of fMRI data. Results presented for simulated as well as real fMRI data show that the proposed method efficiently segments fMRI data into regions of distinct functional activity. View full abstract»

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  • Spread spectrum for chaotic compressed sensing techniques in parallel magnetic resonance imaging

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (445 KB) |  | HTML iconHTML  

    We consider the fast acquisition problem in magnetic resonance imaging (MRI). Often, fast acquisition is achieved using parallel imaging (pMRI) techniques. It has been shown recently that compressed sensing (CS), which enables exact reconstruction of sparse or compressible signals from a small number of random measurements, can accelerate the speed of MRI acquisition because the number of measurements was small. Recently, the spread spectrum (SS) has been utilized to enhance the quality of reconstructed CS image. Also recently, chaotic CS approach potentially offers simpler hardware implementation. In this paper, we combine chaotic CS and spread spectrum technique in order to obtain a fast acquisition in MRI with enhanced quality of reconstructed image. The performance of the proposed method is analyzed using numerical simulation. View full abstract»

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  • Introduction of C/A (covariance/area) with applications to tooth segmentation in dental CT image

    Page(s): 1 - 5
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1040 KB) |  | HTML iconHTML  

    We introduce a coordinate-dependent characteristic of symmetry, which is denoted by C/A. C/A is defined by the division of the covariance (C) by the area (A) of the object of the image. The characteristic has the good properties for the applications to the image processing. We compute the characteristic of ellipse, for which we derive the formula of the perimeter of ellipse. We apply C/A to the segmentation of tooth in a dental CT image. View full abstract»

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  • Biased subspace learning for SVM Relevance Feedback in Content-Based Image Retrieval

    Page(s): 1 - 5
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (299 KB) |  | HTML iconHTML  

    Support Vector Machine (SVM) based Relevance Feedback (RF) is one of the most popular techniques for Content-Based Image Retrieval (CBIR). However, it is not appropriate to directly use the SVM as a RF scheme since it treats the positive and negative feedbacks equally. Additionally, it does not take into account unlabelled samples although unlabelled samples are very helpful in constructing a good classifier. To explore solutions to these two problems, we propose a Biased Maximum Margin Analysis (BMMA) and a Semi-Supervised Biased Maximum Margin Analysis (SemiBMMA) combined with SVM RF in this paper. Extensive experiments on a large real world image database demonstrate that the proposed scheme can significantly improve the performance of the traditional SVM-based RF for CBIR. View full abstract»

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  • Multi-feature content-based product image retrieval based on region of main object

    Page(s): 1 - 5
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (739 KB) |  | HTML iconHTML  

    Content-based image retrieval (CBIR) has got an intense interest and seen considerable progress over the last decade. But most of the time it is only applied in laboratory. One important reason for this is the diversity of images. Different practical situations call for different taxonomy definitions of images, and lead to very different solutions. At present, and even in the foreseeable future, a general purpose CBIR system is not really possible. However, image search engines oriented at specific domains are feasible in technology and also have the actual demand. With the rapid development of electronic commerce, searching specific product by image has become one of the most attractive related research topics. In this paper, we propose a region-based method fit for the content-based retrieval of product images. The method focuses on two key issues: fast extraction of the main region, in which the product locates, as well as efficient shape and color features extraction. To show the validity of the proposed region-based method, compared experiments are carried out and illustrated on the PI 100 dataset. View full abstract»

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  • Fast music information retrieval using PAT tree based dynamic time warping

    Page(s): 1 - 5
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (366 KB) |  | HTML iconHTML  

    Recently, music retrieval is getting more and more attentions, especially for the query by humming (QBH), which is straightforward and convenient for usage. However, the difference between humming phrase matching and the precision of singer humming increase the difficulty of retrieval. Apart from retrieval precision, retrieval time is another issue should be taken into consideration. In this paper, we use two-stage searching approach for music retrieval. Since PAT tree (variant of Patricia tree, practical algorithm to retrieve information coded in alphanumeric) shows an excellent performance in matching partial sequence, in the first stage, the simply reduced note interval is adopted as a key phrase of PAT tree for fast indexing the candidate regions from the feature sequences in the database. In addition, the searching of partial sequences suffering from the insertion, deletion and transposition errors works well in the indexing of reduced note interval. The resulting diversity of candidates may be further reduced via a more complicated dynamic time warping (DTW) comparison in the second step. Our approach not only avoids the exhausted computation in the simple DTW approach, but preservers the fault-tolerance capability in the matching process. View full abstract»

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  • Sequence-based bot detection in massive multiplayer online games

    Page(s): 1 - 5
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (850 KB) |  | HTML iconHTML  

    With the growing popularity of massive multiplayer online games (MMOG), the demand to protect these games and especially the participating players is increasing likewise. In this paper, we discuss a sequence-based solution to protect online games from being exploited by fully automated bots. Our research is based on various commercial and non-commercial bot implementations for the renowned game World of Warcraft. Our evaluation suggests, that a sequence-based detection technique is applicable even for mildly skilled players and effectively protects online games from a negative impact on game economics that causes both, grief to casual gamers and destroys game balance. Our implementation is fit to be deployed on either client- or server side, posing the first player-usable bot detection tool for World of Warcraft. View full abstract»

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  • Direction-of-arrival (DOA) estimation in the presence of array signal coupling

    Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (405 KB) |  | HTML iconHTML  

    Direction-of-arrival (DOA) estimation is an important function in array signal processing. Many DOA estimation algorithms have been proposed catering for different situations and accuracies requirements. Nevertheless, most of these algorithms were designed based on the assumption of using ideal array sensors such as antennas with no interaction between them. A very common type of DOA estimation algorithms are the high-resolution algorithms such as MUSIC and ESPRIT. However, it is well known that MUSIC and ESPRIT are very sensitive to the antenna mutual coupling, which is a common phenomenon in almost all types of antenna arrays. In the presence of antenna mutual coupling, the array manifold is distorted, leading to a degradation of the orthogonality between the signal and the noise subspaces. Consequently, the high-resolution characteristic as predicted by the ideal DOA algorithms is gone. In this talk, a new method is introduced to characterize the antenna mutual coupling effect so that it can be removed from the distorted array manifold. The new method introduces a new concept of “receiving mutual impedance” to characterize the antenna mutual coupling in receiving antenna arrays. The new method is shown to be easy for use in DOA estimation and is almost universally applicable to many types of DOA estimation algorithms. Typical DOA estimation examples will be used to demonstrate the effectiveness of the new method. View full abstract»

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  • Direction of arrival tracking in impulsive noise using particle filtering with fractional lower order moment likelihood

    Page(s): 1 - 5
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (210 KB) |  | HTML iconHTML  

    Tracking the direction of arrival (DOA) of an acoustic source in an impulsive noise environment is a challenging problem due to the non-Gaussian characteristic of the noise process. In this paper, a particle filtering (PF) with fractional lower order moment (FLOM) likelihood model is developed to solve this problem. A constant velocity model is employed to model source dynamics and alpha-stable processes are used to model the impulsive noise environment. Since the second order statistics of alpha-stable processes do not exist, the FLOM matrix of the received array data is used to replace the covariance matrix to formulate a spatial spectra based pseudo likelihood. The likelihood is further exponentially weighted to enhance the weight of particles at high likelihood area and thus reduce the effect due to noise. The simulated experiments show that the proposed PF tracking algorithm significantly outperforms the existing PF as well as the Capon likelihood based PF under different impulsive noise environments. View full abstract»

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  • Optimal sensor pairing for TDOA based source localization in sensor networks

    Page(s): 1 - 5
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (183 KB) |  | HTML iconHTML  

    Source localization based on time-difference-of-arrival (TDOA) measurements from spatially separated sensors is an important problem in radar and sensor networks. While extensive research works have been performed on algorithm development, limited attention has been paid in sensor geometry design. Hence, in this paper, we study the optimal sensor placement for TDOA based source localization problem under two types of sensor pairing: centralized and decentralized. The optimal sensor-target geometries are derived in both static and dynamic source localization scenarios. The Cramer-Rao Bound (CRB) and posterior error covariance are utilized as the estimate accuracy metrics for these two scenarios respectively. Some examples are given to show the optimal sensor formations. View full abstract»

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  • A preliminary study on lifetime maximization in clustered wireless sensor networks with energy harvesting nodes

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (353 KB) |  | HTML iconHTML  

    Clustering is used extensively in wireless sensor networks to optimize lifetime. Within clustering, the optimization of cluster head (CH) location is critical since CHs consume energy faster and have greater influence on lifetime than non cluster head (NCH) sensors. Energy harvesting wireless sensor networks (EH-WSNs) use energy harvesting devices to harvest energy from environment. In contrast with the traditional battery powered wireless sensor networks, EH-WSNs have extended network lifetime substantially. In this paper, we present a single cluster algorithm for lifetime optimization in homogeneous wireless sensor networks with one solar powered sensor. The proposed method could determine the optimal CH location within a given network distribution. We include the solar powered sensor node as relay node for CH and determine the optimal position for it. We evaluate the performance of our method through theoretical analysis as well as simulation. We found through the use of our method, the overall network lifetime could be optimized. View full abstract»

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  • Co-existence with ARQ-based primary system through cooperate-and-access spectrum sharing

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (184 KB) |  | HTML iconHTML  

    We consider spectrum sharing in a cognitive radio network where a secondary user co-exists with an ARQ-based primary user. A spectrum sharing protocol is proposed where the secondary user switches between cooperation and access modes. In the cooperation mode, the secondary system serves as a relay to assist the primary transmission, and in return accumulates credits. The credits allow the secondary user to gain spectrum access by exploiting the ARQ redundant retransmission of the primary user in access mode. We show analytically that as long as the credits accumulated in cooperation mode compensate for the degradation in primary performance during access mode, the proposed protocol achieves an equal (or higher) average throughput for the primary system than the case without spectrum sharing, while providing spectrum access opportunities for the secondary user. View full abstract»

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  • Cooperative and distributed localization for wireless sensor networks in multipath environments

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (387 KB) |  | HTML iconHTML  

    We consider the problem of sensor localization in a wireless network in a multipath environment, where time and angle of arrival information are available at each sensor. We propose a distributed algorithm based on belief propagation, which allows sensors to cooperatively self-localize with respect to one single anchor in a multihop network. Simulations show that although the network is loopy, the proposed algorithm converges with good accuracy, and achieves significant improvement compared with the pairwise localization. View full abstract»

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  • A home-oriented IPTV service platform on residential gateway

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (973 KB) |  | HTML iconHTML  

    In order that end-users in home networks can get opportunities for useful services beyond legacy Internet Protocol TV (IPTV) services, this paper proposes a service platform that resides on the residential gateway (RG) for interworking between home network and IPTV. The proposed service platform is called the home-oriented IPTV service platform (HISP) on the RG (HISP-RG). The proposed HISP-RG provides open architecture and functionalities to enable 3rd party IPTV service providers to deliver locally and directly home-oriented IPTV services to end-users in home networks. The HISP-RG can be an “add-on” solution of the existing RG of ISO/IEC Home Electronic System (HES) or Home Gateway Initiative (HGI), that is, not a “built-in” solution. This paper introduces several home-oriented IPTV services that can be executed and delivered locally through the HISP-RG. Then, the open architecture and functionalities of the HISP-RG are defined and their requirements are specified. Finally, a use case of the HISP-RG is presented for home-oriented IPTV services. View full abstract»

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  • Capacity and BER performance considerations on single-carrier frequency-domain equalization

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (463 KB) |  | HTML iconHTML  

    Single-carrier (SC) waveform has a lower peak-to-average power ratio than multi-carrier waveform. Furthermore, it can exploit the channel frequency-selectivity through frequency-domain equalization (FDE) to improve the transmission performance. SC-FDE is a block transmission. The cyclic prefix (CP) is inserted in front of each data block. Instead of CP insertion, the known training sequence (TS) insertion and zero padding (ZP) can be used. In this paper, performance comparison is made among CP-, TS-, and ZP-SC in terms of the channel capacity and average bit error rate (BER) performance in a frequency-selective Rayleigh fading channel. View full abstract»

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  • Novel node pair selection algorithms for sum-rate enhancement in MIMO interference channel

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (236 KB) |  | HTML iconHTML  

    In multiple-input multiple-output(MIMO) interference channel, multiple transmitters and receivers communicate simultaneously as a pair. We establish the metric for node pair selection algorithm to maximize the sum rate in MIMO interference channel. In this paper, by adjusting node pairs properly, we show that the sum rate can be enhanced. We propose two different node pair selection algorithms to improve the sum rate of MIMO interference channel. Firstly, we propose an optimum node pair selection algorithm by formulating a node pair selection metric to select the best node pairs among all possible node pairs. Then we propose a sub-optimum node pair selection algorithm to lower computational complexity. We confirm from some numerical simulations that the proposed algorithms offer significant sum rate enhancement compared to the case when node pair selection is not considered. View full abstract»

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  • Novel block construction using tail sequences for space time block coded CPM

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (260 KB) |  | HTML iconHTML  

    In this paper, we propose a novel block construction using tail sequence to enable the use of space time block codes (STBC) on continuous phase modulation (CPM). Due to the requirement of phase continuity and the associated inherent memory of CPM, the combination of STBC with CPM is not as straightforward as linear modulation schemes. In the proposed method, to ensure the phase continuity, a tail sequence at the end of each block is inserted to make the end phase of every block satisfy certain restrictions. It is a block based method which only needs information within one block. The tail sequences on two transmitters within one block are the same which means that the determination of the tail sequence is only needed on one transmitter. Compared with existing STBC-CPM techniques, the proposed method could achieve higher throughput and reduce computation complexity. View full abstract»

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  • Keyhole and multi-keyhole MIMO channels: Modeling and simulation

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (271 KB) |  | HTML iconHTML  

    A simple and effective simulation model for keyhole multiple-input multiple-output (MIMO) channels is introduced. The keyhole is modeled as a pair of transmitting and receiving antennas relaying multipath signals from the transmitter region to the receiver region. In the separated transmitter and receiver regions, the double-directional radio channel (DDRC) model is used to model the multipath scattering. Our channel simulation model specially includes the effects of the transmitting and receiving antenna arrays such as antenna gain, radiation efficiency, port reflection loss, mutual coupling, and polarization loss all into the channel matrix through direct antenna numerical calculations with no need for any additional supplementary analytical modeling or postprocessing work. The model is capable of modeling both one-keyhole or multi-keyhole channels. Simulation results have confirmed the validity and accuracy of our simulation model. View full abstract»

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