Dong Su SEONG Ho Sung KIM Kyu Ho PARK
In this paper, we define an attributed random graph, which can be considered as a generalization of conventional ones, to include multiple attributes as well as numeric attribute instead of a single nominal attribute in random vertices and edges. Then we derive the probability equations for an attributed graph to be an outcome graph of the attributed random graph, and the equations for the entropy calculation of the attributed random graph. Finally, we propose the application areas to computer vision and machine learning using these concepts.
A hardware algorithm for modular inversion is proposed. It is based on the extended Euclidean algorithm. All intermediate results are represented in a redundant binary representation with a digit set {0, 1,1}. All addition/subtractions are performed without carry propagation. A modular inversion is carried out in O (n) clock cycles where n is the word length of the modulus. The length of each clock cycle is constant independent of n. A modular inverter based on the algorithm has a regular cellular array structure with a bit slice feature and is very suitable for VLSI implementation. Its amount of hardware is proportional to n.
Tomoko SAWABE Tatsuya FUJII Tetsurou FUJII Sadayasu ONO
In this paper, we evaluate the sustained performance of the prototype SHD (Super High Definition) image processing system NOVI- HiPIPE, and discuss the requirements of a real-time SHD image processing system. NOVI- HiPIPE is a parallel DSP system with 128 PEs (Processing Elements), each containing one vector processor, and its peak performance is 15 GFLOPS. The measured performance of this system is at least 100 times higher than that of the Cray-2 (single CPU), but is still insufficient for real-time SHD image coding. When coding SHD moving images at 60 frames per second with the JPEG algorithm, the performance must be at least ten times faster than is now possible with NOVI- HiPIPE. To extract higher performance from a parallel processing system, the system architecture must be suitable for the implemented process. The advantages of NOVI- HiPIPE are its mesh network and high performance pipelined vector processor (VP), one of which is installed on each PE. When most basic SHD image coding techniques are implemented on NOVI- HiPIPE, intercommunication occurs only between directly connected PEs, and its cost is very low. Each VP can efficiently execute vector calculations. which occur frequently in image processing, and they increase the performance of NOVI- HiPIPE by a factor of from 20 to 100. In order to further improve the performance, the speed of memory access and bit operation must be increased. The next generation SHD image processing system must be built around the VP, an independent function block which controls memory access, and another block which executes bit operations. To support the input and output of SHD moving images and the inter-frame coding algorithms, the mesh network should be expanded into a 3D-cube.
Masashi HOTTA Masahiro GESHIRO Shinnosuke SAWA
The beam propagation method (BPM) is a powerful and manageable method for the analysis of wave propagation along weakly guiding optical waveguides. However, the effects of reflected waves are not considered in the original BPM. In this paper, we propose two simple modifications of the BPM to make it relevant in characterizing waveguide discontinuities at which a significant amount of reflection is expected to be observed. Validity of the present modifications is confirmed by the numerical results for the slab waveguide discontinuities and the butt-joints between different slab waveguides which either support the dominant mode or higher order modes.
Shigeru YOSHIMORI Wataru NAKAHAMA Mitsuo KAWAMURA
Experimental results of an N-S junction and analysis of the results using the Arnold theory were reported. Au and Pb were employed as a normal metal and a superconducting material, respectively. The excess current effect due to the Andreev reflection was observed in the current-voltage characteristics of an N-S junction whose normal resistance was 1.603 Ω. The excess current at 4.62 K was about 0.7 mA when the applied voltage was 2 mV. The barrier height and width were estimated to be 1.0169 eV and 0.7 , respectively, by comparing the experimental results and analysis based on the Arnold theory. In the voltage region less than 2 mV, the theory well agreed with the experiment. Moreover, the applied voltage dependence of the supercurrent and quasiparticle current were separately calculated. It was made clear that the supercurrent was larger than the quasiparticle current in the voltage region less than 2Δ/e, where Δ is the superconducting energy gap and e is the absolute value of an electron's charge. The supercurrent began to gradually saturate when the voltage was higher than Δ/e and became constant at the applied voltage greater than 2Δ/e. In our experiment, the excess current larger than expected from the Arnold theory was observed in the voltage region higher than 2Δ/e.
Shinichiro KOBA Moriaki UCHIYA Akio NAKAO Satoru HIGO Iwazo KAWANO Tetsuya OGUSHI
The barrier-layer was successfully fabricated for a preparation of tunneling junction using high Tc oxidesuperconductor such as Bi-Sr-Ca-Cu-O system. Bi2Sr2Ca2Cu3Ox films were used for both superconducting electrodes and the barrier was mainly Bi2Sr2CaCu2O and the rest that was formed by effects of de-calcium from the first sputtered (2223) film. The reaction of de-calcium occurred immersing it in carbonated water. The change of (2223) phase of BSCCO was confirmed with a comparison of the intensity of X-ray diffraction. The superconductive transition temperature of the junction is different from that of the single film (2223) which had no treatment with carbonated water. Zero-bias-currents through fabricated barrier are observed and the critical currents depend on temperature so far as measured temperature region of 79 K-72 K.
Ruck THAWONMAS Norio SHIRATORI Shoichi NOGUCHI
This paper describes a neural network scheduler for scheduling independent and nonpreemptable tasks with deadlines and resource requirements in critical real-time applications, in which a schedule is to be obtained within a short time span. The proposed neural network scheduler is an integrate model of two Hopfield-Tank neural network medels. To cope with deadlines, a heuristic policy which is modified from the earliest deadling policy is embodied into the proposed model. Computer simulations show that the proposed neural network scheduler has a promising performance, with regard to the probability of generating a feasible schedule, compared with a scheduler that executes a conventional algorithm performing the earliest deadline policy.
Ramjee PRASAD Michel G. JANSEN Adriaan KEGEL
The capacity of a cellular direct sequence code division multiple access system is investigated in situations with and without power control for both the reverse link (from mobile to base station) and the forward link (from base station to mobile). The capacity is defined as the number of simultaneous users per cell with a prespecified performance. A theoretical analysis of the effect of imperfect power control on the reverse link capacity is presented using an analytical model. To investigate the reverse link capacity without any form of power control, a general spatial user distribution is developed which is very suitable for analytical study of any multiple access system with the near-far effect problem. The performance of the reverse link of a CDMA system is also evaluated considering the users located in surrounding cells. Finally, the forward link capacity is studied considering multiple cells. Two possible forward power control schemes, namely carrier-to-interference ratio driven and distance driven systems, are discussed.
Changsuk CHO Haruyuki MINAMITANI
This paper presents a new idea of photometric stereo method which uses 3 point light sources as illumination source. Its intention is to extract the 3-D information of gastric surface. The merit of this method is that it is applicable to the textured and/or specular surfaces, moreover whose environment is too narrow, like gastric surface. The verification of the proposed method was achieved by the theoretical proof and experiment.
Katsumi YAMASHITA M. H. KAHAI Takayuki NAKACHI Hayao MIYAGI
An adaptive multichannel IIR lattice predictor for k-step ahead prediction is constructed and the effectiveness of the proposed predictor is evaluated using digital simulations.
Kumiko IMAI Hironori MATSUBA Peter SPEAR Alistair FIFE
Bi2Sr2Ca1Cu2Ox thick film superconducting shields have been fabricated for use with HTc SQUIDs. Shielding factors and internal noise levels of the shields were measured using a DC SQUID magnetometer. A sample in which BSCCO was coated on the outside of a cylindrical Ag substrate exhibited larger noise levels than that with a sample in which BSCCO was coated on the inside of the Ag cylinder. The difference is explained by the thermally driven (Johnson) noise from the Ag substrate. A sample with the Ag cylinder outside the superconductor and samples with MgO substrates inside the superconductor showed good performance with a shielding factors of 10-8 and internal noise levels which did not exceed the DC SQUID magnetometer resolution (5 fTrms/Hz) at 4.2 K. In addition, the flux relaxation noise of BSCCO superconducting shields was estimated from the relaxation behavior of BSCCO.
Xue Jun MENG Naomichi OKAMOTO Okihiro SUGIHARA
Properties of a strongly-coupled nonlinear directional coupler (NLDC) with a lossy MQW coupling layer is analyzed using the Galerkin finite element method accompanied by a predictor-corrector algorithm. It is shown that the propagation attenuation along the NLDC is considerably smaller than that in the bulk MQW and tends to reduce with the input power. By the presence of losses, the powers guided in two waveguides do not become a maximum and a minimum at the same propagation length, unlike the lossless coupler. The losses make the nonlinear effect weak due to the decrease in guided power, and hence the coupling length decreases and the switching power increases. The extinction ratio of the switching becomes the largest value not in the cases of nonloss and high losses but in the case of moderately high losses, although the switching power is somewhat larger than that of the lossless case.
Junghyun HWANG Yoshiteru OOI Shinji OZAWA
This paper describes an adaptive sensing system with tracking and zooming a moving object in the stable environment. Both the close contour matching technique and the effective determination of zoom ratio by fuzzy control are proposed for achieving the sensing system. First, the estimation of object feature parameters, 2-dimensional velocity and size, is based on close contour matching. The correspondence problem is solved with cross-correlation in projections extracted from object contours in the specialized difference images. In the stable environment, these contours matching, capable of eliminating occluded contours or random noises as well as background, works well without heavy-cost optical flow calculation. Next, in order to zoom the tracked object in accordance with the state of its shape or movement practically, fuzzy control is approached first. Three sets of input membership function--the confidence of object shape, the variance of object velocity, and the object size--are evaluated with the simplified implementation. The optimal focal length is achieved of not only desired size but safe tracking in combination with fuzzy rule matrix constituted of membership functions. Experimental results show that the proposed system is robust and valid for numerous kind of moving object in real scene with system period 1.85 sec.
Shin-ya YOSHINO Akira KOBAYASHI Takashi YAHAGI Hiroyuki FUKUDA Masaaki EBARA Masao OHTO
We have calssified parenchymal echo patterns of cirrhotic liver into four types, according to the size of hypoechoic nodular lesions. Neural network technique has been applied to the characterization of hepatic parenchymal diseases in ultrasonic B-scan texture. We employed a multi-layer feedforward neural network utilizing the back-propagation algorithm. We carried out four kinds of pre-processings for liver parenchymal pattern in the images. We describe the examination of each performance by these pre-processing techniques. We show four results using (1) only magnitudes of FFT pre-processing, (2) both magnitudes and phase angles, (3) data normalized by the maximum value in the dataset, and (4) data normalized by variance of the dataset. Among the 4 pre-processing data treatments studied, the process combining FFT phase angles and magnitudes of FFT is found to be the most efficient.
Isao SHIME Shiro KAMBE Shigetoshi OHSHIMA Katsuro OKUYAMA
Structure and resistivity of BaBiOy were compared with those of Ba1-xLaxBiO3. Decrease in an average Bi valence from 3.91 to 3.03 for BaBiOy leads to an increase in the lattice parameter c from 4.37 to 4.53 , in the unit cell volume from 81 3 to 87 3, and in the resistivity from 10 Ωcm to 2105 Ωcm. It was found that the increase in the unit cell volume and the resistivity was due to change in the average Bi valence. The resistivity of BaBi1-xLaxO3 was compared with that of BaBiOy and Ba1-xLaxBiO3. We also found that pseudocubic Ba1-xLaxBiO3 remains semiconducting as well as pseudotetragonal BaBiOy. The high resistivity in the Ba1-xLaxBiO3 and the BaBi1-xLaxO3 will be useful to the application for the SIS junction.
Yukitoshi SANADA Akihiro KAJIWARA Masao NAKAGAWA
In this paper, we propose an adaptive RAKE receiver, which does not need to send the sounding signals and can track the fluctuations caused by fading. The channel estimation can be done by using a least squares method of the first and second equations suppressing additive noise and tracking the channel fluctuations. It is confirmed by computer simulations that the result has good agreement with theory and the performance is almost same as that of the conventional RAKE with the sounding signals.
Katsuro OKUYAMA Shigetoshi OHSHIMA Hiroaki UENISHI Shiro KAMBE
Amorphous films of YBCO and BSCCO (2212) sputtered on MgO substrate were crystallized using zonemelt technique. For YBCO films, thin Ag intermediate layer was found to be effective in enhancing crystal growth and preferred orientation. Zone-melted BSCCO films included both (2201) phase and Cu(Sr, Ca)O2 in a form of dendritic crystallites. Tc's obtained for YBCO and BSCCO films were 70 and 75 K, respectively.
In this paper we determine the performance of a direct sequence spread spectrum multiple access system where the users utilize different carrier frequencies. This scheme is applicable to a system, such as an indoor wireless communication system utilizing very high frequencies, where the available bandwidth is so large that it is not feasible to spread the signal over the whole band. The multi-user interference is modeled as a compound Gaussian random variable and expressions are found for the variance of the interference as a function of relative phase and frequency parameters. In addition to different carrier frequencies the analysis also accounts for offsets in the chip clock frequencies, general chip pulse shaping function, and different received signal powers. We give results for the error probability in a multiple access system utilizing BPSK, QPSK, and OQPSK modulation.
Kenya UOMORI Shinji MURAKAMI Mitsuho YAMADA Mitsuru FUJII Hiroshi YOSHIMATSU Norihito NAKANO Hitoshi HONGO Jiro MIYAZAWA Keiichi UENO Ryo FUKATSU Naohiko TAKAHATA
To clarify the stereopsis disturbance in patients with Alzheimer's disease (AD), we analyzed binocular eye movement when subjects shifted their gaze between targets at different depths. Subjects are patients with Alzheimer's disease, Mluti-infarct dementia (MID), or Olivopontocerebellar atrophy (OPCA), and healthy controls. Targets are arranged in two ways: along the median plane and asymmetrically crossing the median plane, at distances from the eyes of 1000 mm and 300 mm. When the targets are switched at the onset of a beep, the subjects shifted their gaze to the lit target. The experiment is conducted in a dimly lit room whose structure is capable of providing good binocular cues for depth. In AD subjects, especially in the subjects whose symptoms are moderate (advanced stage), vergence is limited and the change in the convergence angle is small, unstable, and non-uniform. These results are different from those of other patients (MID) and OPCA) or healthy controls and suggest a disturbance of stereopsis in the parietal lobe where AD patients typically have dysfunctions.
Toyohiko HAYASHI Rika KUSUMI Michio MIYAKAWA
This paper presents a technique by which any linear CCD camera, be it one with lens distortions, or even one with misaligned lens and CCD, may be calibrated to obtain optimum performance characteristics. The camera-image formation model is described as a polynomial expression, which provides the line-of-sight flat-beam, including the target light-spot. The coefficients of the expression, which are referred to as camera parameters, can be estimated using the linear least-squares technique, in order to minimize the discrepancy between the reference points and the model-driven flat-beam. This technique requires, however, that a rough estimate of camera orientation, as well as a number of reference points, are provided. Experiments employing both computer simulations and actual CCD equipment certified that the model proposed can accurately describe the system, and that the parameter estimation is robust against noise.