Digital video-on-demand is becoming important, in conjunction with the digitazation of communications and advances in video compression techniques. This paper proposes three new techniques to improve the function and performance of digital video-on-demand systems : multiple readouts of video programs within a few seconds from a disk drive, variable-bit-rate video storage for consistent video quality and efficient multiple readouts, and audio-and-video synchronization that is compatible with a variety of communication networks and video decoding speeds. A new system architecture is also proposed to employ these techniques and video packet transmission. The feasibility of these techniques is experimentally verified. A response time of under one second is achieved from a program request to program initiation on a terminal. In addition, simultaneous access to a video storage server is possible from four terminals if the maximum video bit rate is 2.8 Mbps.

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The influence is investigated of cathode materials on the composition alteration of enclosed gas a DC-type plasma display panel. The I-V characteristics for He-5%Xe gas are quite different than He-2% Xe gas after a 100-hour discharge. These conflicting results are due to the evaporation of Xe in the enclosed gas, with the evaporation time of Xe strongly dependent on the cathode materials. With a 2%Xe content, the Xe evaporates after an 18-hour discharge for the HfC cathode, and after a 500-hour discharge for the LaB₆ cathode With a 5%Xe content, the Xe evaporation time for Xe is ten times longer than the 2% Xe. After the Xe evaporation, the cathode materials generate ten times more Xe gas than those before discharge when they are heated up to 700°C. These results indicate that it is necessary to take into account the composition of the enclosed gas when new cathode materials are developed.

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A pixel of a liquid crystal bistable optical device (LCBOD) with an internal optical feedback is constructed by coupling a TNLC cell and a CdS photoconductive cell. Then, a LCBOD panel for two-dimensional image processing is prepared by arranging the pixels in a 10×10 matrix structure. More complex processing can be attained since arbitrary images can be input electrically by a matrix driving method, as well as by an optical input method. In addition, a new readout method, which does not need any other external devices, is proposed for the iterative operation ; that is, the impedance change (on-state or off-state) is detected by utilizing the matrix electrodes. Some kinds of logic operations between two input images are demonstrated by using the simple system with only one LCBOD panel and its driver.

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A new system for registration correction is developed which employs a cross-correlation function between the green and red signals or the green and blue signals of general picture images from on-line camera operation.
This paper studies the effects of sampling and block size on the correlation function, and proposes a method to improve the detection accuracy for registration error. For pictures with a heavy color component, the compensation value produced by calculating only the correlation value dose not correspond to the true registration error value. This system eliminates the miscompensation effects caused by the color component. Although this system is for tube cameras, it is also effective for solidstate cameras using CCDs because registration errors can be caused by a lens aberration, which is inevitable in lens systems.

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Markov properties are the stochastic processes which determine the dependency of a current event upon earlier events. This study applies this statistical index to spontaneous blink intervals to quantitatively analyze the factors which regulate interblink intervals. Vertical electro-oculography is used to measure the blinks of normal subjects for thirty minutes with and without a mental task. As a result, subjects without a mental task exhibit strong Markov properties, which suggests that blinks evoked by stationary physical stimulus such as dryness and dustiness occur depending upon earlier events. On the other hand, subjects with a mental task exhibit weak Markov properties, which suggests that blinks evoked by transient cognitive factors occur randomly according to the current state of the subjects.

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This paper describes a new conformance test (CT) method for a layer-3 of HBS standard. A test coordination procedure is developed to create an appropriate and economical implementation under test (IUT). A few examples are given of a test method for a system common command (SCC) and a communication sequence (CS) for HBS standard. The SCC specification examples are shown of test cases and test suites. The CS specifications can be made by combinations of a few SCC specifications. The system experiment shows that the CT program can be developed as simple structured programming by paying attention to a test sequence community. Finally, the standard software functions of the system under test (SUT) are clearly indicated.

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A simultaneous transmission system for dual video signals is developed, which can transmit two video signals through a single analog channel.
The system uses an analog bandwidth compression technique and the encoded signal is in the NTSC form. This system divides the two-dimensional division multiplex form.
This paper discusses problems of developing and evaluating this equipment for practical use.

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[in Japanese]

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