The graph is useful expression of abstract general idea. Accordingly, the graph is utilized broadly as a basic model in various fields such as systems engineering, information engineering. On this Account, the problem to draw a graph automatically is important. But, it is difficult to draw a well-balanced graph of network automatically. In this paper, I define the ideal distance between nodes as changeable in a graph drawing algorithm of network by a dynamic simulation. And I define the interaction of nodes such that the larger the distance is, the smaller the interaction of nodes is. Finally, by simulations I present that this graph drawing algorithm is useful for complexly graph drawing.

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This report describes a remote collaboration system that enables distributed users to handle an object simultaneously in a shared virtual environment. Collaboration is indispensable to human society, and requires the interaction of individuals within groups and the relation of groups to one another. The sharing a virtual environment via advanced communication network enables the distributed designers to collaborate feeling as they are in the same place-remote collaboration. The collaboration needs the shared environment kept same on every site if users handle an object simultaneously. This report proposes a remote collaboration system using force displays to keep the shared virtual environment same.

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Various approaches have been tried for the pitch changing of musical sounds.These methods are mostly based on the manipulation of the sampling-rate. They work rather well for sounds of musical instruments but not for human voices. They change not only the pitch of the voice but also the timbre, so it is often difficult to guess the identity of the singer by hearing the output of a conventional pitch changer. We must change only the pitch of the singer's voice while preserving its timbre. This paper describes a new method of the singer's voice pitch changing by introducing Linear Predictive Coding (LPC) which is used in speech analysis-synthesis data compression.

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Humans perceive an edge even for smooth luminance change. In this paper, we examine estimating the subjective edge location of a blurred pattern that has smooth luminance change and is shaped a concentric circle on a CRT. It is then maked clear that the characteristic of perception is non-linear. We propose a new model that contains non-linear transducer function for luminance and predicts a perceived edge location better than the output with a linear operator, which is the zero-crossing with simple Lapracian-Gaussian filter. We compare several kinds of non-linear transducer functions found in the mechanism of visual processing. It appears that the new models which contains a logarithmic function or an exponential function, simulates human data very well. Finally, we propose an equation that evaluates variability in subjectively estimation of the edge location.

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An object that is reproduced by a stereoscopic display is perceived in front of the screen with depth distortion by human observers when the reproduced area of the object is truncated by a picture frame. Experimental results suggested that (1) the occlusion condition, which contradicts a real three-dimensional situation (i.e., valid), caused this distortion ; (2) when an observer misfused a binocular image that included the monocular region, he perceived the frontal-parallel plane as a slanted one ; (3) this misperception was caused by asymmetric information synthesis between the pictorial and binocular occlusion cues when the binocular disparity sign was different. We show that the technique of adding a virtual picture frame (i.e., virtual window) in front of the real screen enables human observers to perceive the correct depth.

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Picture quality of bit-rate reduction coding is generally estimated by subjective assessment tests. To apply coding scheme to broadcasting, it is necessary to investigate a frequency distribution of picture characteristic in additon to subjective assessment. Although ITU-R proposes the 'criticality' which represents difficulty for Coding, the definition of criticality hasn't be established yet. We have defined the criticality as output bits of a hybrid DCT encoder with a fixed quantizer, and evaluated correlation with picture quality measured by subjective assessment tests for some sequences. From the results of the criticality distribution of real TV programs, we evaluated the disirtion degree of coded pictures in TV services.

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An objective evaluation measure AWSNR (Advanced Weighted Signal to Noise Ratio) which compensates coding noise by considering entropy in every 16×16 pixels sub-block is proposed. In order to clarify the relationship between MOS (Mean Opinion Score), SNR and entropy, a subjective evaluation test using twelve kinds of textures with ten different noise level is carried out. After the noise compensation factor is experimentally derived from te entropy-SNR characteristics when MOS=4,342 images with five kinds of coding noise or with random noise are evaluated subjectively and objectively. The result shows an improved correlation coefficient with the MOS-AWSNR of 0.83,compared to 0.64 with the MOS-SNR.

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