Prof. Takeshi Ozeki Profile

Prof. Takeshi Ozeki

at Sophia Univ

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Publications (8)

Proceedings Article | 21 October 2004 Paper

Ultrafast OTDM/WDM networks by use of photonic processing

Hideyuki Sotobayashi, Wataru Chujo, Takeshi Ozeki

Proceedings Volume 5581, (2004) https://doi.org/10.1117/12.582931

KEYWORDS: Wavelength division multiplexing, Ultrafast phenomena, Multiplexing, L band, Picosecond phenomena, Eye, Control systems, Optical testing, Dispersion, Multiplexers

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Proceedings Article | 14 August 2003 Paper

Ultrafast photonic technologies for the hierarchical hybrid OTDM/WDM photonic networks

Hideyuki Sotobayashi, Wataru Chujo, Takeshi Ozeki

Proceedings Volume 5246, (2003) https://doi.org/10.1117/12.512287

KEYWORDS: Wavelength division multiplexing, Picosecond phenomena, Optical amplifiers, Multiplexing, Ultrafast phenomena, L band, Multiplexers, Time division multiplexing, Eye, Control systems

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Proceedings Article | 1 July 1992 Paper

Design of knowledge-based image retrieval system: implications from radiologists' cognitive processes

Olivia Liu Sheng, Chih-Ping Wei, Takeshi Ozeki, Theron Ovitt, Jiro Ishida

Proceedings Volume 1654, (1992) https://doi.org/10.1117/12.60276

KEYWORDS: Image processing, Image retrieval, Picture Archiving and Communication System, Data communications, Radiology, Distributed computing, Knowledge acquisition, Cognitive modeling

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Proceedings Article | 1 July 1991 Paper

Picture archiving and communications systems protocol based on ISO-OSI standard

Ralph Martinez, Jiseung Nam, William Dallas, Masakazu Osada, Kevin McNeill, Takeshi Ozeki, Ken-Ichi Komatsu

Proceedings Volume 1446, (1991) https://doi.org/10.1117/12.45264

KEYWORDS: Picture Archiving and Communication System, Standards development, Data communications, Radiology, Medical imaging, Digital imaging, Databases, Interfaces, Imaging systems, Information security

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Proceedings Article | 1 August 1990 Paper

Distributed database design and modeling for PACS

Olivia Liu Sheng, Hong-Mei Garcia, Chih-Ping Wei, Takeshi Ozeki, Patricia McNulty

Proceedings Volume 1234, (1990) https://doi.org/10.1117/12.19012

KEYWORDS: Picture Archiving and Communication System, Databases, Image retrieval, Data modeling, Performance modeling, Medical imaging, Surgery, Image processing, Imaging systems, Telecommunications

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Proceedings Article | 1 August 1990 Paper

Requirement analysis for PACS database system

Olivia Liu Sheng, Hong-Mei Garcia, Takeshi Ozeki, Hui-Chin Wang, Mike Whetter, Takahiro Ema, Masakazu Osada, Yuki Fukushima

Proceedings Volume 1234, (1990) https://doi.org/10.1117/12.19013

KEYWORDS: Picture Archiving and Communication System, Image retrieval, Databases, Data storage, Diagnostics, Imaging systems, Radiology, Image processing, Medical imaging, Surgery

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Proceedings Article | 1 August 1990 Paper

Network data rate requirement analysis for picture archiving and communication systems

Akihiro Toshimitsu, Yuki Fukushima, Kiyoshi Tawara, Masakazu Osada, Takahiro Ema, Takeshi Ozeki, Ken-Ichi Komatsu, William Dallas

Proceedings Volume 1234, (1990) https://doi.org/10.1117/12.18980

KEYWORDS: Picture Archiving and Communication System, Databases, Radiology, Image compression, Circuit switching, Imaging systems, X-ray imaging, X-rays, Data archive systems, Data communications

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Proceedings Article | 1 August 1990 Paper

Performance evaluation of a picture archiving and communication system using stochastic activity networks

Ralph Martinez, William Sanders, Yasser Alsafadi, Jiseung Nam, Takeshi Ozeki, Ken-Ichi Komatsu

Proceedings Volume 1234, (1990) https://doi.org/10.1117/12.18994

KEYWORDS: Picture Archiving and Communication System, Stars, Stochastic processes, Medical imaging, Imaging systems, Image transmission, Instrument modeling, Performance modeling, Databases, Image processing

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The concept of picture archiving and communication systems (PACS) is now widely accepted in the medical community. In order to bring the concept to reality, however, innovative designs and implementations are needed. One such design is a fiber optic star based PACS, conceived by the University of Arizona and Toshiba corporation. This PACS network is based on a multiplexed passive star local area network with wavelength-division multiplexing to provide separate logical channels for transfer of control and image data. The system consists of an Image-Network (INET), for image transfer at a rate of 140 Mbps, and a Control-network (CNET), operating at 10 Mbps, for mediating the flow of image transfers. INET is a circuit switched network where a network supervisor grants users permission to transfer images over it, while CNET employs the CSMA/CD protocol for bus arbitration. Before such a system can be deployed, an accurate evaluation study must be carried out to estimate its performance characteristics. Such evaluations are complicated both by the complexity of the PACS itself and the varied demands that are placed on such a system. An novel approach based on siochastic aciiviiy neiworks, a stochastic extension of Petri nets, is useful in this regard. Stochastic activity networks were used to develop a detailed model of the command and image channels. The performance of the system was then evaluated under realistic workload conditions. In particular, we were able to estimate a number of important performance variables including the image response time, command channel delay, and queue length each type of node and the network supervisor. The results 1) show that stochastic activity networks are an appropriate model type for evaluating picture archiving and communication systems, 2) delineate the workload conditions under which PACS may effectively operate, and 3) show that even when these conditions are exceeded, the command channel load remains extremely light. Results of this type are useful both to designers of other PACS networks and those interested in this particular PACS design.

Showing 5 of 8 publications

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