Jun-Pyo HONG Jung-Jun LEE Sang-Bong JUNG Seung-Hong HONG
Heart sound is an acoustic wave generated by the mechanical movement of the heart and blood flow, and is a complicated, non-stationary signal composed of many signal sources. It can be divided into normal heart sounds and heart murmurs. Murmurs are abnormal signals that appear over wider ranges of frequency than normal heart sounds. They are generated at random spots in the whole period of heart sounds. The recognition of heart sounds is to differentiate heart murmurs through patterns that appear according to the generation time of murmurs. In this paper, a group of heart sounds was classified into normal heart sounds, pre-systolic murmurs, early systolic murmurs, late systolic murmurs, early diastolic murmurs, and continuous murmurs. The suggested algorithm was standardized by re-sampling and then added as an input to the neural network through wavelet transform. The neural network used Error Back - Propagation algorithm, which is a representative learning method, and controlled the number of hidden layers and the learning rate for optimal construction of networks. As a result of recognition, the suggested algorithm obtained a higher recognition rate than that of existing research methods. The best result was obtained with the average of 88% of the recognition rate when it consisted of 15 hidden layers. The suggested algorithm was considered effective for the recognition of automatic diagnosis of heart sound recognition programs.
Correct and quick generation of a membership function is the key point when we implement a real-time fuzzy logic controller. In this Letter, we presented two efficient VLSI architectures, one to generate triangle-shaped and the other to generate trapezoid-shaped membership functions. Simulation results show that our designs require lower hardware cost but achieve faster working rate.
Lan CHEN Hidetoshi KAYAMA Narumi UMEDA
The IMT-2000 service launched in 2001 in Japan is expected to popularize multimedia services such as videophone, visual mail, video, and music distribution. With the rapidly increasing demand for high-speed mobile multimedia and the need to support diversified requirements of users, wireless Quality of Service (QoS) resource management has become an important and challenging issue. In order to improve the system capacity and rate of satisfied users, in this paper, a novel wireless QoS resource management scheme is proposed to carry out radio resource cooperative control among base stations. Computer simulations indicate that the proposed QoS resource cooperative control exhibits superior performance over conventional ones, and that a higher rate of satisfied users is achieved.
This paper deals with a design problem of a robust controller which achieves not only robust stability but also a performance robustness for linear systems with structured uncertainties satisfying matching condition. The performance robustness means that comparing the transient behavior of the uncertain system with a desired one generated by the nominal system, the deterioration of control performance is suppressed. In this approach, the control law consists of a state feedback with the fixed gain designed by using the nominal system, a state feedback with an adaptive gain determined by a parameter adjustment law and a compensation input for the purpose of keeping transient behavior as closely as possible to the desirable one. We show the parameter adjustment law in order to guarantee robust stability and that the condition for the existence of the compensation input is equivalent to the Riccati equation for the standard linear quadratic control problem. Finally, numerical examples are presented.
Il-Yong PARK Hee-Joon PARK Jeong-Woo LEE Shin-Won KANG Jin-Ho CHO
An effective compensation method for the IR lamp deterioration in NDIR (non-dispersive infrared) capnograph system is proposed. The optical chamber with two IR (infrared) lamps has been designed newly and an electronic hardware for the control of lamp intensity has been implemented. After applying the proposed optical chamber and the reference lamp control circuit to the NDIR type capnograph system, it is identified that the proposed method can compensate the lamp deterioration effectively.
Ming-Tuo ZHOU Awnashilal B. SHARMA Jian-Guo ZHANG Forhadul PARVEZ
A simple configuration for millimeter-wave fiber-wireless transmission, with remote local-oscillator (LO) delivery from the central office, both for the uplink and for the downlink, and a simple, cost-effective, base-station solution is proposed. Under the assumption of using commercially available components and a conventional single-mode fiber (with dispersion of 17 ps/nm/km at 1.55 µm), our numerical results show that, with a laser linewidth of 150 MHz, a laser power of 0 dBm and an optical gain of only 6 dB, it is possible to transmit, without repeaters, data rates of 622 Mbit/s across about 18 km at a bit-error-rate of 10-9. By increasing the optical gain to 24 dB, the link length can be increased to approximately 67 km for a laser linewidth of 75 MHz and to 78 km for a laser linewidth 1 MHz.
Arata KOIKE Satoko TAKIGAWA Kiyoka TAKEDA Akihisa KOBAYASHI Masashi MORIMOTO Konosuke KAWASHIMA
In this paper, we first investigate the characteristics of movie contents over the Internet. As in the previous studies, we found the lognormal-distribution well fits the distribution of file size for the whole set of general movie contents. When we specifically focus on the subset that consists of movie trailers, however, it shows different distribution from the lognormal-distribution. Our analysis shows it is similar to an exponential-distribution. We here assume that movie trailers are one of the relevant contents for Contents Delivery Networks (CDN) or Peer-to-Peer (P2P) file exchange communities. We further studies the relationship between playing duration and file size for the movie trailers and we did not find any linear correlation among them. We next consider bandwidth requirements to retrieve movie trailer contents. Our objective is to make it possible for user to view the contents in real-time. Many previous studies investigate bandwidth requirement based only on the file size distribution. In this paper, we analyze the traffic design criteria for CDN or P2P by taking into account both of the results for the file size distribution and the relationship between playing duration and file size for movie trailers. Simulation studies reveal the impact for the bandwidth requirement.
Hiroyuki TAKIZAWA Taira NAKAJIMA Kentaro SANO Hiroaki KOBAYASHI Tadao NAKAMURA
The equidistortion principle[1] has recently been proposed as a basic principle for design of an optimal vector quantization (VQ) codebook. The equidistortion principle adjusts all codebook vectors such that they have the same contribution to quantization error. This paper introduces a novel VQ codebook design algorithm based on the equidistortion principle. The proposed algorithm is a variant of the law-of-the-jungle algorithm (LOJ), which duplicates useful codebook vectors and removes useless vectors. Due to the LOJ mechanism, the proposed algorithm can establish the equidistortion condition without wasting learning steps. This is significantly effective in preventing performance degradation caused when initial states of codebook vectors are improper to find an optimal codebook. Therefore, even in the case of improper initialization, the proposed algorithm can achieve minimization of quantization error based on the equidistortion principle. Performance of the proposed algorithm is discussed through experimental results.
In provisioning packet data service on wireless cellular networks, a scheme of altering connection status between mobile and base stations appeared with an effort to utilize resource during idle periods. A critical issue in such scheme of sojourn and transition on the connection states is to determine a maximum time to sojourn at each state. An excessive sojourn time leads to resource invasion by inactive stations, while a high cost of re-establishing connection components is imposed by an insufficient sojourn. Thus, the maximum sojourn times must be optimized in consideration of the two conflicting arguments. In this paper, we consider a generic scheme of connection status transitions and formulate a decision problem to determine maximum sojourn times by introducing a loss function which reflects the cost of connection re-establishment as well as the loss induced by inefficient resource usage. From the decision problem, we derive an optimal value for maximum sojourn time, identified as Bayes rule, by observing the delay time of last packet to have posterior information about the length of upcoming idle period. From the analytical results, we show the Bayes sojourn time is trivial under a constraint on loss coefficients when packet arrivals follow a Poisson process.
Rangsan WONGSAN Chuwong PHONGCHAROENPANICH Monai KRAIRIKSH Jun-ichi TAKADA
This paper presents the analysis of the impedance characteristics of a sectoral cylindrical cavity-backed axial slot antenna excited by a probe. The integral equations are derived based on boundary conditions of the proposed structure and they are expressed in terms of dyadic Green functions and unknown current densities. The dyadic Green functions are obtained by using the eigenfunction expansion method together with application of scattering superposition techniques. The unknown current densities are solved by the Method of Moments. The input impedance is subsequently determined from the unknown electric current density at the probe. Numerical results of input impedance and return loss are demonstrated as functions of frequency for various parameters such as cavity length, cavity radius ratio, slot location in φ direction, slot length and probe length. Calculated results are validated by the measurements. At the operating frequency, it is found that the result is sufficiently accurate. The results from this study are very useful for the design of a sectoral cylindrical cavity-backed axial slot array antenna excited by a probe with omnidirectional beam radiation.
Dae-Hyun KIM Jung-Hoon KIM Yong-In YOON In-Hwan OH Jong-Soo CHOI
In this paper, we propose an algorithm that automatically generates the intermediate scenes using the bidirectional disparity morphing (BDM) from the parallel stereo images. The two-step search strategy is used for speeding up the computation of the bidirectional disparity map and three occluding patterns are used for smoothing the computed disparities more elaborately. Using the bidirectional disparity map, we interpolate the left and the right image to their intermediate scenes. Then we dissolve two interpolated images into the desired intermediate scene which the holes are removed and the effect of the disparity estimation errors is minimized. We implemented the proposed algorithm on TM1300 supported by TriMedia using pSOSytem which enables to do multiprocessing. As a result, we can interpolate the high-quality intermediate scenes with real-time process.
This paper proposes the IMADF (improved multiplication-free adaptive digital filter) algorithm to cancel the background noise that spans nearly all frequency bandwidths in biomedical signals. Under conditions of zero-mean, wide-sense stationary and white Gaussian noise, we analyze the convergence characteristics of the IMADF with a FSE (fractionally-spaced equalizer). In the experimental results, the IMADF algorithm has the advantage in which has superior to a condition of low-frequency and slow data speed. This application gives an important significance in ensuring the objectivity of clinical information and in promoting the representation and the disease diagnosis.
Joon-il SONG Jun-Seok LIM Koeng-Mo SUNG
Wireless LAN (WLAN) systems transmit and receive via a common frequency band. In this band, signals of other wireless applications operate on a WLAN beamformer as interferences, and so the problem in adaptive antenna is increasing the canceling performance in the presence of moving interference sources. The performance of conventional adaptive beamformer is severely degraded and the robust adaptive beamformer must be equipped with additional sensors to obtain desired performances. Therefore, in order to avoid having to install additional sensors, an efficient algorithm is necessary. In this paper, we introduce a fast adaptive algorithm with variable forgetting factor, which does not require any further additional modifications. Through computer simulations, we can obtain better performances than those of other techniques under a variety of operating conditions.
Zaher AGHBARI Kunihiko KANEKO Akifumi MAKINOUCHI
In this paper, we present a novel approach for efficient search of high-dimensional databases, such as video shots. The idea is to map feature vectors from the high-dimensional feature space into a point in a low-dimensional distance space. Then, a spatial access method, such as an R-tree, is used to cluster these points based on their distances in the low-dimensional space. Our mapping method, called topological mapping, guarantees no false dismissals in the result of a query. However, the result of a query might contain some false alarms. Hence, two refinement steps are performed to remove these false alarms. Comparative experiments on a database of video shots show the superior efficiency of the topological mapping method over other known methods.
Ryuichi FUJIMOTO Chihiro YOSHINO Tetsuro ITAKURA
A simple modeling technique for symmetric inductors is proposed. Using the proposed technique, all model parameters for an equivalent circuit of symmetric inductors are easily calculated from geometric, process and substrate resistance parameters without using electromagnetic (EM) simulators. Comparison of simulated results with measured results verifies the effectiveness of the proposed modeling technique up to 5 GHz with center-tapped or non-center-tapped configurations.
Jee Woong KANG Kwang Bok (Ed) LEE
We propose an extended one-shot decorrelating detector (EOS-DD) which may be viewed as a generalized double window multiuser detector (DW-MD) for asynchronous direct-sequence code-division multiple-access (DS/CDMA) systems in frequency selective fading environments. The EOS-DD extends a processing window and the received signal over an extended window is utilized for decorrelating. The effects of the window size on BER performance are investigated by numerical analysis. Analysis and simulation show that the EOS-DD is superior to the one-shot decorrelating detector (OS-DD) and finite memory length truncated decorrelating detector (FIR-DD) in terms of noise enhancement and near-far resistance. It is also shown that the EOS-DD with window size 4 can provide significantly improved performance compared to the EOS-DD with window size 2.
Zenshiro KAWASAKI Keiji SHIBATA Masato TAJIMA
This paper presents an extension of the database query language SQL to include queries against a database with natural language annotations. The proposed scheme is based on Concept Coupling Model, a language model for handling natural language sentence structures. Integration of the language model with the conventional relational data model provides a unified environment for manipulating information sources comprised of relational tables and natural language texts.
Osamu WATANABE Mitsuyuki ASHIDA Tetsuro ITAKURA Shoji OTAKA
A linear-in-dB VGA of the current-divider type is fabricated in 0.25 µm CMOS technology. Two gain compensation techniques are proposed in order to compensate the gain deviations due to a MOSFET which has a square-law characteristic or an exponential-law characteristic determined by its current density. Temperature compensation techniques are also proposed. Measure results obtained at 380 MHz are a gain range of 80 dB, a gain error of 3 dB, and an NF of 11 dB.
Yasuhiro TAKAHASHI Kei-ichi KONTA Kazukiyo TAKAHASHI Michio YOKOYAMA Kazuhiro SHOUNO Mitsuru MIZUNUMA
This paper describes a design of a Carry Propagation Free Adder/Subtracter (CPFA/S) VLSI using the Adiabatic Dynamic CMOS Logic (ADCL) circuit technology. Using a PSPICE simulator, energy dissipation of the ADCL 1 bit CPFA/S is compared with that of the CMOS 1 bit CPFA/S. As a result, energy dissipation of the proposed ADCL circuits is about 1/3 as high as that of the CMOS circuits. The transistors count, propagation-delay time and energy dissipation of the ADCL 4 bit CPFA/S are compared with those of the ADCL 4 bit Ripple Carry Adder/Subtracter (RCA/S). The transistors count and propagation-delay time are found to be reduced by 7.02% and 57.1%, respectively. Also, energy dissipation is found to be reduced by 78.4%. Circuit operation and performance are evaluated using a chain of the ADCL 1 bit CPFA/S fabricated in a 1.2 µm CMOS process. The experimental results show that addition and subtraction are operated with clock frequencies up to about 1 MHz. In addition, the total power dissipation of the ADCL 1 bit CPFA/S is 28.7 µW including the power supply.
Chiao-Chan HUANG Zhi-Feng HUANG Ann-Chen CHANG
A minor component analysis approach based on the generalized sidelobe canceler is presented to realize the blind suppression of multiple-access interference in multicarrier code division multiple access systems. With a rough user-code and timing estimations, this proposed method of less computation performs the same as minimum mean square error detectors and outperforms existing blind detectors. Simulation results illustrate the effectiveness of the blind multiuser detection.