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Image improvement in pinhole SPECT using complete data acquisition combined with statistical image reconstruction

International Congress Series 2004年第C期1265卷 101-105页

作者： Zeniya, Tsutomu Watabe, Hiroshi Aoi, Toshiyuki Kim, Kyeong Min Teramoto, Noboru Hayashi, Takuya Sohlberg, Antti Kudo, Hiroyuki Iida, Hidehiro Department of Investigative Radiology National Cardiovascular Center Research Institute Suita Osaka 565-8565 5-7-1 Fujishiro-dai Japan Department of System Science Graduate School of Informatics Kyoto University Kyoto 606-8501 Yoshida-Honmachi Sakyo Japan Department of Clinical Physiology and Nuclear Medicine Kuopio University Hospital FIN-70211 Kuopio P.O. Box 1777 Finland Department of Computer Science Graduate School of Systems and Information Engineering University of Tsukuba Ibaraki 305-8573 1-1-1 Tennoudai Tsukuba Japan

Pinhole single-photon emission computed tomography (SPECT) with high spatial-resolution is suitable for small-animal imaging, but has limitations associated with spatial-resolution inhomogeneity or axial blurring. We have hypothesized that this blurring is due to incompleteness of projection data acquired by a single circular pinhole orbit. And we have developed a pinhole SPECT system with two circular orbits which satisfy Tuy's condition so as to provide complete data for 3D pinhole SPECT reconstruction within the whole field-of-view (FOV);a dedicated 3D ordered subsets expectation maximization (3D-OSEM) reconstruction method for two-orbit data. This study is aimed at evaluating accuracy and impact of this system. In this system, not the camera but the object rotates and the two orbits are 90° and 45° relative to object's axis. Experiments using a multiple-disk phantom filled with ^99mTc solution and a mouse bone scan using ^99mTc-labeled HMDP agent were carried out. The Feldkamp's filtered back-projection (FBP) method and the 3D-OSEM method were applied to these data sets. The axial blurring was apparent on images reconstructed by FBP for single-orbit data, while the 3D-OSEM using two-orbit data dramatically improved the resolution homogeneity and statistical noise property, and also demonstrated considerably better image quality in the mouse scan. © 2004 Elsevier B.V.

关键词： Complete data acquisition Pinhole SPECT Small animal Statistical image reconstruction Tuy's condition

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Transistor characteristics of thermal CVD carbon nanotubes field emission triode

Transistor characteristics of thermal CVD carbon nanotubes f...

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International Conference on Vacuum Nanoelectronics (IVNC)

作者： Y.M. Wong W.P. Kang J.L. Davidson W. Hofmeister S. Wei J.H. Huang Dept. of Electrical Engineering and Computer Science Vanderbilt Univ. Nashville TN USA Interdisciplinary Graduate Program in Material Science Vanderbilt Univ. Nashville TN USA Dept. of Materials Science and Engineering National Tsing Hua Univ. Hsinchu Taiwan ROC

In this paper, the study of thermal CVD grown CNT field emitters in a triode amplifier configuration is reported. The DC characteristics of the CNT triode are investigated, including I/sub a/ vs. V/sub a/ for different V/sub g/. Moreover, DC parameters such as transconductance, amplification factor and anode resistance of the triode amplifier are determined. It was shown that a higher amplification factor can be achieved with optimum gate-anode-cathode spacing such that the cathode is effectively shielded from the anode by the gate but the anode still collects all electrons emitted from the cathode. High emission current at low gate voltage is key to achieving high transconductance. This can be obtained by optimum configuration of high-density CNTs array in a triode structure with a common gate.

关键词： Carbon nanotubes Voltage Anodes Materials science and technology Current measurement Palladium Silicon Furnaces Temperature Cathodes

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A low-power CMOS neural amplifier with amplitude measurements for spike sorting

A low-power CMOS neural amplifier with amplitude measurement...

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IEEE International Symposium on Circuits and systems (ISCAS)

作者： T. Horiuchi T. Swindell D. Sander P. Abshier Institute for Systems Research Neuroscience and Cognitive Science Program University of Maryland College Park MD USA Electrical and Computer Engineering Department University of Maryland College Park MD USA Electrical and Computer Engineering Department Electrical Engineering Department Pennsylvania State University State College PA USA

Integrated, low-power, low-noise CMOS neural amplifiers have recently grown in importance as large microelectrode arrays have begun to be practical. With an eye to a future where thousands of signals must be transmitted over a limited bandwidth link or be processed in situ, we are developing low-power neural amplifiers with integrated pre-filtering and measurements of the spike signal to facilitate spike-sorting and data reduction prior to transmission to a data-acquisition system. We have fabricated a prototype circuit in a commercially-available 1.5 /spl mu/m, 2-metal, 2-poly CMOS process that occupies approximately 91,000 square /spl mu/m. We report circuit characteristics for a 1.5 V power supply, suitable for single cell battery operation. In one specific configuration, the circuit bandpass filters the incoming signal from 22 Hz to 6.7 kHz while providing a gain of 42.5 dB. With an amplifier power consumption of 0.8 /spl mu/W, the rms input-referred noise is 20.6 /spl mu/V.

关键词： Sorting Signal processing Low-noise amplifiers Microelectrodes Bandwidth Integrated circuit measurements Prototypes CMOS process Power supplies Batteries

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WebComposer: a tool for the composition and execution of Web service-based workflows

WebComposer: a tool for the composition and execution of Web...

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Proceedings of the Latin American Web Congress (LA-Web)

作者： L.A.G. da Costa P.F. Pires M. Mattoso COPPE-Systems Engineering and Computer Science Program Federal University of Rio de Janeiro Rio de Janeiro Brazil DCC-IM/NCE Federal University of Rio de Janeiro Rio de Janeiro Brazil

We present the WebComposer tool for the automatic composition and execution of Web service-based workflows. We use ontologies to describe and browse workflows. We associate messages and operations with workflow domain concepts using WSDL extensibility. The automatic workflow implementation through WebComposer enables the full separation of the workflow logic and the implementation technology. WebComposer provides the execution of ad-hoc programs by users and the automatic maintenance of these programs, as the available Web services are altered.

关键词： Web services Ontologies Software agents Automatic logic units Semantic Web systems engineering and theory computer science Web sites Information resources Application software

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Automatic composition of Web services with contingency plans

Automatic composition of Web services with contingency plans

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IEEE International Conference on Web Services (ICWS)

The semantic Web technology and the Web services description language extensibility may be combined to describe services in an unambiguous and machine interpretable way, automating Web services discovery, selection and invocation. In this paper, we present an algorithm and a prototype for the automatic composition of Web services that implement workflows described in a high level language. Our approach has many advantages comparing to the manual creation of a simple program composition, such as smaller implementation time and cost, reliability with the generation of contingency plans, greater capacity to evolve with the dynamic service discovery, and faster execution time with the use of heuristics. We use the OWLS ontology to semantically describe Web services metadata and indexes to help selecting them. The proposed algorithm considers that equivalent services may have different interfaces and also respects preferences of the users.

关键词： Web services Semantic Web Ontologies programming profession Prototypes Robustness systems engineering and theory computer science High level languages Costs

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Conformational addressing using the hairpin structure of single-strand DNA

Lecture Notes in Computer Science (including subseries Lectu...

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Lecture Notes in computer science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) 2004年 2943卷 219-224页

作者： Kameda, Atsushi Yamamoto, Masahito Uejima, Hiroki Hagiya, Masami Sakamoto, Kensaku Ohuchi, Azuma Honmachi 4-1-8 Kawaguchi 332-0012 Japan Division of Systems and Information Engineering Graduate School of Engineering Hokkaido University North 13 West 8 Kita-ku Sapporo 060-8628 Japan Department of Computer Science Graduate School of Information Science and Technology University of Tokyo 7-3-1 Hongo Bunkyo-ku Tokyo 113-8656 Japan Department of Biophysics and Biochemistry Graduate School of Science University of Tokyo 2-11-16 Yayoi Bunkyo-ku Tokyo 113-0032 Japan

In this paper, we demonstrate through a chemistry experiment that conformational addressing can be achieved using the hairpin structure of a DNA molecule. The hairpin structure made by single-strand DNA (ssDNA) self-hybridization is made into the address part of conformational addressing, and it is assumed that the memory is read by opening this hairpin. The hairpin is continuously arranged in order to divide the address by class. Reading a sub-address requires an appropriate input oligomer to be added, when the preceding hairpin has been opened. We investigated, through the chemistry experiment, whether it would be possible to open the hairpin by the addition of an input oligomer into a solution that contained a hairpin-formed ssDNA. © Springer-Verlag 2004.

关键词： DNA

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Cooperative embodied communication emerged by interactive humanoid robots

Cooperative embodied communication emerged by interactive hu...

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IEEE International Workshop on Robot and Human Communication (ROMAN)

作者： D. Sakamoto T. Kanda T. Ono M. Kamashima M. Imai H. Ishiguro ATR Intelligent Robotics and Communication Laboratories Soraku-gun Kyoto Japan Department of Media Architecture Future University-Hakodate Hakodate Hokkaido Japan Department of Computer Science Graduate School of Science and Technology Keio University Yokohama Kanagawa Japan Department Adaptive Machine Systems Graduate School of Engineering Osaka University Osaka Japan

Research on humanoid robots has produced various uses for their body properties in communication. In particular, mutual relationships of body movements between a robot and a human are considered to be important for smooth and natural communication, as they are in human-human communication. We have developed a semi-autonomous humanoid robot system that is capable of cooperative body movements with humans using environment-based sensors and switching communicative units. And we conducted an experiment using this robot system and verified the importance of cooperative behaviors in a route-guidance situation where a human gives directions to the robot. This result indicates that the cooperative body movements greatly enhance the emotional impressions of human in a route-guidance situation. We believe these results allow us to develop interactive humanoid robots that sociably communicate with humans.

关键词： Humanoid robots Robot sensing systems Intelligent robots Human robot interaction Laboratories Sensor systems Communication switching computer science Adaptive systems Educational institutions

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Localized public-key management for mobile ad hoc networks

Localized public-key management for mobile ad hoc networks

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IEEE Conference and Exhibition on Global Telecommunications (GLOBECOM)

作者： Ruidong Li Jie Li H. Kameda Peng Liu University of Tsukuba Tsukuba Japan Department of Computer Science Graduate School of Systems and Information Engineering University of Tsukuba Tsukuba Japan Cyber Security Lab School of Information Sciences and Technology Pennsylvania State University University Park USA

A mobile ad hoc network (MANET) is the cooperative engagement of a collection of wireless mobile nodes without aid of any established infrastructure or centralized administration. The conventional security solutions to provide key management through accessing trusted authorities or centralized servers are infeasible for this new environment since mobile ad hoc networks are characterized by the absence of any infrastructure, frequent mobility, and wireless links. In this paper, we propose an on-demand, fully localized, and hop-by-hop public key management scheme for MANETs. It can be performed by generating public/private key pairs by nodes themselves, issuing certificates to neighboring nodes, holding these certificates in their certificate repositories, and providing an authentication service quickly adaptive to the dynamic topology of the network without relying on any servers. Also, our scheme can be performed successfully as long as there is a physical communication line between two nodes, and it is accustomed well to the on-demand routing of MANETs.

关键词： Public key Mobile ad hoc networks Network servers Cities and towns Communication system security Authentication computer network management computer science systems engineering and theory computer security

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Using a non-prior training active feature model

Lecture Notes in Computer Science (including subseries Lectu...

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Lecture Notes in computer science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) 2004年 3333卷 69-78页

作者： Kim, Sangjin Kang, Jinyoung Shin, Jeongho Lee, Seongwon Paik, Joonki Kang, Sangkyu Abidi, Besma Abidi, Mongi Department of Image Engineering Graduate School of Advanced Imaging Science Multimedia and Film Chung-Ang University 221 Huksuk-Dong Tongjak-Ku Seoul 156-756 Korea Republic of Imaging Robotics and Intelligent Systems Laboratory Department of Electrical and Computer Engineering University of Tennessee Knoxville TN 27996-2100 United States

This paper presents a feature point tracking algorithm using optical flow under the non-prior training active feature model (NPT-AFM) framework. The proposed algorithm mainly focuses on analysis of deformable objects, and provides real-time, robust tracking. The proposed object tracking procedure can be divided into two steps: (i) optical flow-based tracking of feature points and (ii) NPT-AFM for robust tracking. In order to handle occlusion problems in object tracking, feature points inside an object are estimated instead of its shape boundary of the conventional active contour model (ACM) or active shape model (ASM), and are updated as an element of the training set for the AFM. The proposed NPT-AFM framework enables the tracking of occluded objects in complicated background. Experimental results show that the proposed NPT-AFM-based algorithm can track deformable objects in real-time. © Springer-Verlag 2004.

关键词： Optical flows

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Implementation of new services to support ubiquitous computing for campus life

Implementation of new services to support ubiquitous computi...

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IEEE Workshop on Software Technologies for Future Embedded systems

作者： Tack-Don Han Cheolho Cheong Jae-Won Ann Jong-Young Kim Hyung-Min Yoon Chang-Su Lee Hyon-Gu Shin Young-Jin Lee Hyoung-Min Yook Myoung-Hoon Jeon Jung Soo Choi Joo-Hyeon Lee Young-Woo Sohn Yoon Su Baek Sang-Yong Lee Eun-Dong Shin WooShik Kang SeongWoon Kim Department of Computer Science Yonsei University Seoul South Korea Dept. of Computer Science Yonsei University Seodaemun-gu Seoul KR Dept. of Comput. Sci. Yonsei Univ. South Korea Department of Clothing & Textiles Yonsei University Seoul South Korea Dept. of Clothing & Textiles Graduate Program in Cognitive Science Yonsei University Seoul South Korea Graduate Program in Cognitive Science Department of Mechanical Engineering Yonsei University Seoul South Korea Dept. of Mechanical Engineering Department of Psychology Yonsei University Seoul South Korea Dept. of Psychology ColorZip Media Inc. Seoul South Korea Yonsei University ColorZip Media Inc. Samsung Advanced Institute of Technology Seoul South Korea

ISBN: (纸本)0769521231

Many new services have emerged to realize ubiquitous computing environments, owing to the increasing supply of mobile devices and more widespread Internet and wireless network facilities. We introduce the U-Campus (ubiquitous computing for campus) service. This study has been conducted through interdisciplinary research by four participating departments. The U-campus project is part of the UTOPIA project (Ubiquitous computing TOwn Project: Intelligent context Awareness), which covers town- and city-wide environments. Currently, a test bed for U-campus has been constructed to support various services suck as U-profile, U-messaging and U-campus tour guide services. Students, professors, school staffs, and campus visitors can easily access the various available campus services by using image-based sensors and mobile devices such as CDMA cellular phones or WiFi smart phones. The major purpose of this research is to provide a context-aware U-campus environment to users by utilizing sensors and mobile devices currently available in the public sector and the marketplace.

关键词： Ubiquitous computing Intelligent sensors Mobile computing IP networks Web and internet services Wireless networks Context awareness Testing Educational institutions Image sensors

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