| C1-1 | Title | Invited Lecture: Adaptive Signal Processing for Wireless Communications Systems; Theory and Applications |
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| Author(s) | Prof. S. -J. Chern | |
| Abstract | Wireless communications have become one of the most significant active
areas of technological developments in recent year. Similar to the developments
in wireline capacity in 1990s, the demand for new wireless capacity is
growing at a very rapid pace. Due to the spectacular growth of voice and
video communications over the Internet, it is imperative that both wireless
and multimedia should be brought together to achieve broadband wireless
communications. This brings the various communities, industries, and business
to the forefront to integrate and interact among them. As a result of this
the availability of frequency bands become scare and the service providers
have to live with whatever frequency bands they have within their grasp.
The spatial processing that exploits the diversity provided by smart antenna
(SA) or intelligent antenna (IA) arrays, in which the adaptive beamformer
is employed, is a significant approach to increase the efficiency of wireless
system capacity and performance, without allocating additional frequency
spectrum. It allows the system to make full use of spatial diversity due
to multiple antennas. To achieve the demand for high data-rate wireless
transmission, in future mobile broadband communications, the multiple antenna
systems, where both the base station as well as mobile phone are with multiple
antennas, will become most significant solution to solve the present acquired. In this presentation, the adaptive signal processing techniques for above mentioned wireless communication architectures would be addressed. We will start with the review of the fundamental theory of adaptive filtering technologies, especially, the important family based on the least squares (LS) criterion and its modified version. The advantages and weakness of this approach with applications to the antenna array beamforming, and the multi-user detection problems for the DS-SS CDMA and MC-CDMA receivers will be emphasized, under various channel environments. We will also comment on some current on-going activities and possible research topics in this area. |
| C1-2 | Title | Invited Talk: Adaptive DS-SS CDMA Multi-user Detector with Simplified Sliding Window LC-RLS Algorithm for Near-Far Effect Reduction |
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| Author(s) | C. -H. Sun and S. -J. Chern | |
| Abstract | In this paper, a simplified linearly constrained recursive least-squares ((LC-RLS) algorithm, with sliding window (SW), referred to as the SW-LC-RLS algorithm, is devised to enhance the tracking capability of direct-sequence spread-spectrum (DS-SS) code division multiple access (DS-SS CDMA) detector for multiple access interference (MAI) suppression, when the problem of Near-Far Effect is considered. Then the MAI suppression capability are examined for the proposed scheme, and compared with the conventional LC-RLS algorithm. To be more specific, under multi-user environments we first consider the case, in which ten users are joined to the system at different time instant with near-far ratio (NFR) to be 20dB, while later at other time instant six users are out of the system. Next, to further investigate the effect of near-far for MAI suppression, the situation where different pairs of users are joined and out of the system at different time instant, with NFR=30 dB, is considered. Finally, the advantage of the proposed scheme is verified via computer simulation, we learn that with our proposed scheme, better performance, in terms of faster convergence rate in transient state and larger steady state output signal-to-interference-plus-noise-ratio (SINR), could be achieved compared with the conventional LC-RLS and the LC-LMS algorithms. |
| C1-3 | Title | Face Recognition Approach Based on Region-Divsion Vector Quatization Histogram Method |
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| Author(s) | Q. Chen, K. Kotani, F. Lee, and T. Ohmi | |
| Abstract | We have developed a very simple yet highly reliable face recognition method called VQ histogram method. Codevector referred (or matched) count histogram, which is obtained by Vector Quantization (VQ) processing of facial image, is utilized as a very effective personal feature value. Furthermore, for adding the geographic information of the face to improve the recognition accuracy, a region-division (RD) VQ histogram method is proposed in this paper. We divide the facial area into 5 regions relating to the facial parts (forehead, eye, nose, mouth, jaw). Recognition results with different parts are first obtained separately and then combined by weighted averaging. Top1 recognition rate of 97.4% is obtained by using FB task (1195 images) in the standard FERET database. By using the private database, which was taken in practical but yet reasonably regulated environment, Top1 recognition rate of 100% is realized. |
| C1-4 | Title | Frame displacement correction using camerawork estimation for old film restoration |
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| Author(s) | M. Hagiwara, M. Abe and M. Kawamata | |
| Abstract | This paper proposes a frame displacement correction method using camerawork estimation for old films. Frames of old films may suffer from vertical and horizontal movements, which we call the frame displacement. Subpixel displacement correction is needed for stabilization of old films. For subpixel displacement estimation, we analyze the phase-only correlation and propose an estimation method which is based on approximating the phase-only correlation by the sinc function. Moreover, we propose a cut change detection method and a camerawork estimation method using the characteristics of the phase-only correlation, because camerawork estimation is necessary for frame displacement correction of old films. Experimental results show that the proposed method can estimate the frame displacement and the camerawork. Visual inspection shows that the frame displacement is significantly reduced by the proposed method. |
| C1-5 | Title | Novel Properties of the Gramians and Second-Order Modes of Linear State-Space Systems and Their Power Complementary Systems |
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| Author(s) | S. Koshita, M. Abe and M. Kawamata | |
| Abstract | This paper reveals new properties of the Gramians and second-order modes of linear state-space systems. First, an explicit proof is given to the property that a positive definite solution of the bounded-real Riccati equation consists of the Gramians of linear systems and their power complementary systems. This result provides derivation of the property of the second-order modes; the values of the second-order modes of linear systems are all bounded by the gain of the systems. As an application of this property, a new formula for evaluating quantization errors of optimal digital filters is constructed. |
| C1-6 | Title | Arbitrary Scale Image Enlargement with the Prediction of High Frequency Components |
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| Author(s) | S. Yuan, A. Taguchi and M. Kawamata | |
| Abstract | Image enlargement with unknown higher frequency components prediction is a kind of super resolution processing. In this paper, we propose a super resolution algorithm for arbitrary scale image enlargement based on the Laplacian pyramid (LP) representation. Conventional LP super resolution algorithms can only finish the calculation of integer pyramid stages, and thus it is only capable of expanding an image up by a factor of two in size. In this paper, we present the algorithm for arbitrary pyramid stages calculation, and we then utilize it to get the arbitrary scale enlargement ability. |
| C1-7 | Title | Blind Separation of Signals with Mixed Sub-Gaussian and Super-Gaussian Probability Distributions |
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| Author(s) | M. Tufail, M. Abe and M. Kawamata | |
| Abstract | In this paper we address the problem of blind separation of independent signals with mixed sub-Gaussian and super-Gaussian probability distributions. Blind extraction of these signals using Independent Component Analysis (ICA) requires proper selection of certain nonlinear activation functions (AFs) in order to ensure that the natural gradient (NG) algorithm remains locally stable. Since these AFs depend upon the (unknown) probability density functions (pdf) of sources, they are estimated online by modeling the source distribution as a linear combination of a sub-Gaussian and a super-Gaussian pdf. This hypothesized source distribution model has only one parameter, which is adapted online by minimizing the mutual information using exponentiated gradient algorithm. Effectiveness of this approach is illustrated by the computer simulations. |
| C2-1 | Title | Invited Lecture: Analog Decoding of Capacity-Approaching Error Control Codes: State of the Art and Future Challenges |
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| Author(s) | Asst. Prof. V. Gaudet | |
| Abstract | Capacity approaching codes, such as Turbo codes and Low Density Parity Check codes, have recently been incorporated into numerous data communication standards. Digital VLSI implementations of these codes are frequently slow or power-hungry. On the other hand, novel analog implementations of decoders are demonstrating up to two orders of magnitude speed or power improvements over corresponding digital implementations. This paper discusses the current state of the art of analog decoders and offers insights into future iterative decoding technologies. |
| C2-2 | Title | Design of a Multiple-Valued Current-Mode Circuit Based on Signal Multiplexing for Asynchronous Duplex Communication |
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| Author(s) | T. Takahashi and T. Hanyu | |
| Abstract | This paper presents a high-speed duplex asynchronous communication scheme based on 1-phase dual-rail encoding and its circuit implementation. Since control signals and data from mutual modules can be multiplexed using a multi-level dual-rail codeword, the number of communication steps can be greatly reduced, which results in high-speed communication without any additional wire. The hardware is simply implemented by utilizing multiple-valued current-mode circuit because all the information can be superposed on the same lines. The throughput of the proposed scheme becomes about twice with slight hardware expansion in comparison with that of a previous uni-directional scheme. |
| C2-3 | Title | Absolutely Secure Secret Key Shared from Random Deal of Cards |
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| Author(s) | K. Koizumi, T. Mizuki and T. Nishizeki | |
| Abstract | Two players can share an absolutely secure secret key from a random deal of cards by playing a card game based on a protocol such as the transformation protocol and the key set protocol proposed by Fischer and Wright. However, it has not been known how many secret bits can be shared from a random deal of cards. We design a new protocol better than the two protocols, and obtain a recursive formula to compute the minimum number of secret bits shared by any randomized execution of our protocol. |
| C2-4 | Title | Tree-Based Flow Tracing for Locating Network Pathologies |
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| Author(s) | K. Koide, G. M. Keeni, T. Saito, G. Kitagata and N. Shiratori | |
| Abstract | If measurement points are in a leaf site, cause of the limitation of the network information, it is difficult to catch dynamics, or causes of pathologies at other network places in the Internet. Also there are some difficulties to use active polling tools like `traceroute' due to policy related limitations. TCP retransmission packets, which is one of indications about network pathologies, can be observed at a leaf site passively. We propose the tree-based method that traces traffic flows that contains TCP retransmissions and the others, and associates the flows with BGP routing information. We show the capability of the method for real traffic data. |
| C2-5 | Title | Advanced QoS Control of Multimedia Communication Service based on Knowledge Circulation |
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| Author(s) | S. Imai, T. Suganuma and N. Shiratori | |
| Abstract | We present a design of a Knowledge Circulation Framework for Quality of Service (QoS) control of Multimedia Communication Service (MCS). This framework aims at realizing user-oriented MCS by enabling effective circulation of QoS control knowledge in the network. In this paper, we propose a design of the framework with knowledge-based multiagent system. In the framework, QoS control knowledge is actively circulated getting on the agents. We implement a prototype of real-time bidirectional MCS (videoconference system) using this framework. Also we perform some experiments using the system to evaluate the effectiveness of the framework. |
| C2-6 | Title | "CoFIP" for music signals |
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| Author(s) | K. Sonoda, R. Nishimura and Y. Suzuki | |
| Abstract | Considering a digital watermarking scheme for multi-cast network distribution, embedding process should be on the user side to reduce the amount of data transmission while the original signal should not be delivered for a security reason. To meet these requirements, CoFIP (COntents FIngerPrinting) was proposed. The basic idea is to broadcast contents in a form of a package consisting of several variations of some partial objects made by watermarking and its remainder. An individualized content is obtained by combining the remainder and the partial objects specified by a CoFIP key. In this report, an implementation of CoFIP for digital music signals is proposed. |
| C2-7 | Title | Construction of Expert Guided Decision Tree on Numeric Database |
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| Author(s) | J. Chun, K. Sadakane and T. Tokuyama | |
| Abstract | In this paper, we propose the technique for constructing a decision tree with high prediction accuracy. There is over fitting as a problem at the time of constituting a decision tree. If the optimal decision tree is used to training data, trade-off that the prediction accuracy over unknown data will fall will arise. In this paper, we propose a new method for removing these drawbacks. Indeed, we give optimized numeric association rules with multi attributes, and give layered-structure numeric association rules. We use layered-structure numeric association rules as expert of decision tree. |
| C2-8 | Title | Local Vector Coding for Quasi-Periodic Signal |
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| Author(s) | M. Ito and M. Yano | |
| Abstract | Voiced sound and sound of some musical instruments show quasi-periodicity, of which amplitude and frequency change continually. Provided that the initial phase, the instantaneous amplitude and frequency of the sound, it is easy to identify its waveform. However, it is great difficult to accurately solve the inverse problem, that is, to determine these parameters from the quasi-periodic sound wave. Here, we propose the LVC (Local Vector Coding) method, which enables the estimation of not only the instantaneous amplitude and frequency but also their change rates. Using two kinds of input signals, we demonstrated that the LVC method is superior in estimation of these parameters to the traditional method. The decoded signal well agrees with the input one, showing maximally -34 dB of the residual energy to that of the input signal. |
| C2-9 | Title | An authentication method for CSCW system using face recognition |
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| Author(s) | D. Yin, S. Omachi and H. Aso | |
| Abstract | Although a large number of studies have been made on face recognition and CSCW but few studies have ever tried to combine the face recognition techniques and CSCW techniques. We propose a new approach to combine these two techniques to build an automatic real-time face recognition system for CSCW users authentication. One of the most conventional authentication method used for CSCW systems is password, which is very simple and does not require any special device. However, it can be easily divulged by others. To tackle this problem, in this paper we present an approach for the user authentication of CSCS system using face recognition techniques. A first step towards face recognition is the localization of face region. For the segmentation of face region we employ color information and template matching. For recognition purpose we employ PCA method. |
| C3-1 | Title | Invited Lecture: Design of Multicarrier CDMA using Code Selection for High Data Transmission |
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| Author(s) | Prof. Y. Park | |
| Abstract | Multicarrier CDMA direct sequence code-division multiple access (MC DS) CDMA is a candidate for high data rate application. However, a main disadvantage of Multi-Carrier CDMA is the high PAR(peak to average power ratio) of the output signal by using large number of subcarriers. To solve this problem, we apply code selection method in Multicarrier DS-CDMA, Multi-carrier Code Select CDMA(MC CS-CDMA). After applying code selection method, we can reduce the number of subcarriers in MC DS-CDMA system. When we assume the same bandwidth and transmission data rate with MC DS CDMA to make a fair comparison of the performance, this scheme provides the following advantage: The effect of PAR reduction can be achieved. And the remained bandwidth by reducing subcarrier can be used for time/frequency diversity gain. It is shown that the MC CS-CDMA compared to conventional Multicarrier Systems in the presence of these assumption, produces to get not only robustness against PAR (peak-to-average power ratio) by reducing the number of subcarriers, but also achieves the better performance than MC DS-CDMA because of increasing spreading gain and diversity gain. However, the disadvantages of MC CS-CDMA are at the expense of higher system complexity of receiver according to the increasing various parallel input bits and the number of finger of rake Receiver. Also, the capacity can be decreased compared to the MC DS-CDMA by increasing the number of spreading code per user. |
| C3-2 | Title | Invited Talk: Investigation on Effect of Space-Time Block Codes (STBC) Considering Frequency and Time Diversity in OFCDM Broadband Packet Wireless Access |
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| Author(s) | K. W. Ryu and Y. Kishiyama | |
| Abstract | This paper investigates on effect of space-time block codes (STBC) over the frequency and time spreading in orthogonal frequency and code division multiplexing (OFCDM) broadband packet wireless access, in order to use common control channel. For comparing with STBC scheme, we also investigate single antenna transmission and time-switched transmit diversity (TSDT) with the same transmit power and the same number of receiver antenna. The simulation results show that the performance of STBC is degraded compared to those of other two schemes since the time and frequency diversity gain is sufficiently obtained due to the frequency-domain spreading and the time-domain packet combing. |
| C3-3 | Title | Precise analysis of supermode noise in an actively and harmonically mode-locked fiber laser using large-scale computation |
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| Author(s) | S. Waiyapot, T. Hirooka, and M. Nakazawa | |
| Abstract | An actively and harmonically mode-locked fiber laser is considered as one promising pulse source for high speed optical transmission as it can produce picosecond pulses at giga-hertz repetition rates. Recently there have been a lot of interests in laser output spectrum since the phase locking of many of longitudinal modes of the laser establishes stabilized optical comb frequencies. In this paper, we describe for the first time precise modeling of the laser spectrum by numerical analysis of a large number of pulses over long time scale using large-scale computation. This allows us to describe the spectrum degradation due to supermode noise accurately. |
| C3-4 | Title | The design and fabrication of dispersion-flattened photonic crystal fiber in the 800 nm region |
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| Author(s) | H. Hasegawa, T. Hirooka, M. Yoshida and M. Nakazawa | |
| Abstract | Photonic crystal fiber, which has an array of air holes around a core, has attractive features including endlessly single-mode operation and arbitrary dispersion control. The shift in its zero dispersion towards shorter wavelengths is particularly interesting as it may offer the possibility of high-speed optical communication at new wavelengths. We describe the characteristics of fabricated photonic crystal fiber that we had previously designed numerically. The fabricated photonic crystal fiber will be useful for high-speed transmission in the 800 nm region. |
| C3-5 | Title | Throughput of Slotted ALOHA DS-CDMA with Random TPC in a Single-cell Environment |
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| Author(s) | Z. Wang, E. Kudoh and F. Adachi | |
| Abstract | In this paper, the theoretical analysis of system-throughput and user-throughput of slotted ALOHA DS-CDMA with random TPC is presented and the impact of random TPC parameters on their relationship is discussed. The link capacity is defined as the number of maximum users accommodated in the system while keeping the user-throughput below a prescribed value. It is found that the link capacity may not necessarily be maximized when the system-throughput is maximized. |
| C3-6 | Title | Transmission performance evaluation of single-carrier MIMO multiplexing |
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| Author(s) | A. Nakajima, D. Garg and F. Adachi | |
| Abstract | Recently, Multi-Input Multi-Output (MIMO) is gaining much attention for very high speed data communications. In this paper, frequency-domain iterative interference cancellation is proposed for the single-carrier MIMO multiplexing. The bit error rate (BER) performance of single-carrier MIMO multiplexing in a frequency-selective Rayleigh fading environment is evaluated by computer simulation to show that the proposed frequency-domain iterative interference cancellation is very effective to improve the BER performance. |
| C3-7 | Title | Channel estimation and performance evaluation for uncoded MC-CDMA system |
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| Author(s) | S. Takaoka and F. Adachi | |
| Abstract | Multi-carrier code division multiple access (MC-CDMA) is considered as a promising candidate for the next generation wireless communication system. This paper evaluates the uncoded BER performance of MC-CDMA, including OFDM as a special case, in a frequency-selective fading channel and compares with DS-CDMA using rake combining. Also, we discuss the channel estimation for multi-carrier signals. |
| C3-8 | Title | Peformance evaluation of DS-CDMA with frequency-domain equalization |
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| Author(s) | K. Takeda and F. Adachi | |
| Abstract | In a severe frequency-selective fading channel, the bit error rate (BER) performance of direct-sequence code division multiple access (DS-CDMA) with rake combining significantly degrades compared to multi-carrier (MC)-CDMA. However, recently single-carrier (SC) transmission techniques (including DS-CDMA) have been looked over again with application of frequency-domain equalization (FDE) as in MC-CDMA. In this paper, the BER performance of DS-CDMA with FDE is evaluated by computer simulation and compared with that of MC-CDMA. |
| C3-9 | Title | Turbo coded HARQ for high speed downlink packet access in mobile radio |
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| Author(s) | D. Garg and F. Adachi | |
| Abstract | OFDM, MC-CDMA and DS-CDMA are being researched vigorously as the prospective signaling technique for the next generation mobile communications systems, which will be characterized by the broadband packet technology. With packet transmission, hybrid ARQ (HARQ) will be inevitable for error control. HARQ with turbo codes is one of the promising techniques. In this paper, we introduce turbo coded HARQ to DS-CDMA with minimum mean square error frequency-domain equalization (MMSE-FDE) and compare its throughput performance with OFDM and MC-CDMA. It is found that the throughput of DS-CDMA with MMSE-FDE is the same as or better than that of MC-CDMA. However, with higher level modulation, coded OFDM is better than either MC-CDMA or DS-CDMA. |
| C2-10 | Title | REFWA: A Novel Scheme to Improve the Performance of TCP over Low-Earth Orbit Satellite Communications Systems |
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| Author(s) | T. Taleb, N. Kato and Y. Nemoto | |
| Abstract | As originally specified, TCP did not perform well over satellite network systems. This paper addresses some vexing attributes that impair TCP performance in LEO satellite networks and proposes a scheme that allows satellite systems to automatically adapt to the number of active TCP flows, the free buffer size and the bandwidth-delay product of the network. Simulation results elucidate that the proposed scheme substantially improves the system fairness, reduces the number of packet drops and makes better utilization of the bottleneck link. The results demonstrate also that the proposed scheme works properly in more complicated environments where connections traverse multiple bottlenecks. |
| C2-11 | Title | A Japanese dialogue-based CALL system to detect grammar errors of learners |
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| Author(s) | O. P. Kweon, A. Ito, M. Suzuki and S. Makino | |
| Abstract | This paper describes a dialogue-based CALL (Computer Assisted Language Learning) system. One of the major problems in CALL systems is that learners are usually assigned a passive role. Learners have no practices in composing their own utterances. The other major problem is that lots of conventional CALL systems are pronunciation exercise systems. However, pronunciation exercise is only a part of exercise needed to increase a learner's communication skill. In this paper, we propose a dialogue-based CALL system that enables exercise learners' grammatical errors and lexical errors. |