Foundation of Computer Science Laboratory

Takafumi Hayashi Professor	Shuxue Ding Associate Professor	Yodai Watanabe Assistant Professor





The research and education activities in the laboratory focus on the theoretical foundations of computers and computations, including broad applications in science and engineering. Our work covers algorithms and computation, programming languages, discrete mathematics, statistical signal processing, neuro-computing, optimization, simulated acoustics and related topics.

Areas of our research interest include Combinatorics and its applications; Spread spectrum communication; Sparse representation and sparse component analysis; Content-Aware networking; Secure Cloud Computing; SOA, SaaS, IaaS, Daas, and Paas; Signal processing; Image analysis for measurement; Enterprise Integration and Messaging Network: Security Management; Networks; GRID as a Service Oriented Architecture Based System; Security and management of computer system for e-Government; Blind source separation and independent component analysis, and their applications in acoustic signals and vital signs; Neural computing and brain-style signal processing; Optimization and machine learning; Time-reversal wave propagation in ergodic environment and its applications in acoustics, ultrasonics and telecommunications;

The following combined research is running: independent component analysis and sequence design. independent component analysis and network anomaly detection. distributed data store integration and cryptography.

Faculty of the FCS laboratory teach Computer Literacy, Programming I, Algorithms and Data Structures, Advanced Algorithms, Digital Signal Processing, Linear Systems, Information Security, SCCPs and other selective courses. Students join faculty research and also develop their own research themes. We participate in various research projects of JSPS, NIFS, RIKEN etc.

Refereed Journal Papers

[sding-01:2009]	W. Liu and S. Ding. Performance Analysis of the Iterative Decision Method for Optimal Multiuser Detection. ICIC Express Letters, 3(3 (B)):615– 619, September 2009.
	The iterative decision method has been proposed to solve the optimal multiuser detection (OMD) problem efficiently [6]-[9]. In contrast to conventional detection methods, this method can determine most binary variables of OMD optimally, rather than approximately, with a low computational complexity. However, the reason that the iterative decision method works so efficiently for OMD has not yet been well established. In this paper, we present a systematic answer to this question. Invoking the properties of OMD, we prove that the iterative decision method can optimally determine the binary variables of OMD with a high predictable probability and furthermore, we determine the probability explicitly in terms of system configurations. These provide solid theoretical foundations for the justification and efficiency of the iterative decision method for solving the OMD problem. Since the probability depends on the configuration parameters in a complex fashion, we also present an approximation for the probability dependence that can be calculated more easily.
[sding-02:2009]	W. Liu and S. Ding. The Diagonal Loading Beamformers for the PAM Communication Systems. International Journal of Innovative Computing, Information and Control, 5(9):2907–2916, September 2009.
	The diagonal loading method is a simple and efficient method that can improve the robustness of beamformers. However, determining an ideal diagonal loading factor (DLF) is not a trivial problem. Maximizing the signal to interference-plus-noise ratio (SINR) can be one criterion for determining an ideal DLF. Unfortunately, the maximizing SINR is not realistic for practical applications. Although beamformers are widely used in radar, sonar and many other applications, in this paper, we consider a beamformer for PAM communication systems. In PAM communications, user information is coded into a sequence with the constant modulus (CM) in the baseband. Obviously, if the beamformer can cancel interference and noise sufficiently, the outputs of the beamformer should satisfy the CM condition more precisely. Therefore, minimizing the CM error (MCME) criterion can act as a reasonable substitution for maximizing the SINR criterion. In this paper, we present a cost function for the MCME criterion. We also propose a search algorithm for DLF determination by minimizing the cost function. Numerical experiments show the effectiveness of the proposed method.
[takafumi-01:2009]	T. Hayashi. A Class of Zero-Correlation Zone Sequence Set Using a Perfect Sequence. Signal Processing Letters, IEEE, 16(4):331–334, April 2009.
	This letter introduces a novel method of sequence construction having a zero-correlation zone. The cross-correlation function and the side-lobe of the auto-correlation function of the proposed sequence set is zero for the phase shifts within the zero-correlation zone. The proposed zero-correlation zone sequence set can be generated from an arbitrary perfect ternary sequence, the length of which is the product of a pair of odd integers ( (2k+1)(2n+1) for k ges 1 and n ges 0). The width of the zero-correlation zone of the proposed sequence set can be longer than the length of the perfect sequence that is used for constructing the proposed sequence set. The proposed sequence construction can generate an optimal zero-correlation zone sequence set that satisfies the theoretical bound of the sequence member size for the zero-correlation zone and the sequence period.

Referred Proceeding Papers

[sding-03:2009]	W. Liu, Q. Liu, J. Li, M. Jin, and S. Ding. An Iterative Algorithm for Joint Beamforming and DoA Estimation. In Proc. The 19th Intelligent System Symposium (Fan 2009) and The 1st International Workshop on Aware Computing (IWAC09), pages 674–678. Japan Society for Fuzzy Theory and Intelligent Informatics, International Workshop on Aware Computing Organizing Committee and The University of Aizu, Japan Society for Fuzzy Theory and Intelligent Informatics, 2009.
	The MUSIC direction of arrival (DoA) estimation algorithm is known to degrade due to effects of imprecise knowledge about the array manifold. We have made some numerical experiments for the fact revisited. The simulation results showed an interesting phenomenon that has not been reported yet in literature. That is, if there are more than one signal sources impinging to the array, the performance of MUSIC algorithm really degraded dramatically due to the effects of imprecise array manifold; however, if there is only one signal source impinging to the array, the DoA estimation for the single source is robust. Invoking this phenomenon, we propose an iterative algorithm for joint beamforming and DoA estimation. In the viewpoint of DoA, an essential difference between the proposed algorithm and conventional DoA estimation algorithms is that the proposed algorithm includes a processing of beamforming but the conventional DoA algorithms do not include it. Numerical experiments have shown the robustness of the proposed algorithm against imprecise knowledge on the array manifold.
[takafumi-02:2009]	Yooin Choi, J. Terazono, K. Kawauchi, K. Itabashi, H. Fukuhara, I. Koseda, R. Fujita, T. Miyazaki, S. Saito, J. Iwase, and T. Hayashi. Networkcentric mashup for a sensor network that uses a messaging network. In ICCAS-SICE, 2009, pages 1980–1983, Aug. 2009.
	The present paper describes a mashup and an approach by which to integrate a sensor network using a messaging network. A messaging network is an overlay network that has a rich set of message handling capabilities. The use of a messaging network enables the complexity and maintenance burden of the integrated sensor information systems to be reduced. Mashup refers to the use of different data or services for the purpose of providing value-added information or efficient use of information. The proposed approach generates an SOA-based sensor network design and mashup.
[takafumi-03:2009]	J. Terazono, H. Fukuhara, T. Yamada, T. Nihei, K. Suzuki, I. Koseda, R. Fujita, T. Miyazaki, S. Saito, A. Kara, and T. Hayashi. A sensor network using content-aware messaging network architecture. In ICCASSICE, 2009, pages 5055–5058, Aug. 2009.
	The present paper describes an approach to the construction of a sensor network using a messaging network. A messaging network is an overlay network with a set of content-aware message handling capabilities. The use of a messaging network can reduce the complexity and maintenance burden of integrated sensor information systems. Message mediation (a function of the messaging network) enables interoperation of various applications and integration of diverse sensor data. Subscription (another concept in the messaging network) enables proper information delivery of the sensor data to each user. The proposed approach is helpful in implementing an SOA-based sensor network and enables flexible sensor network configuration and utilization.
[takafumi-04:2009]	Junya Terazono (The University of Aizu), Ryosuke Nakamura, Shinsuke Kodama, Naotaka Yamamoto (AIST), Hirohide Demura, Naru Hirata, Yoshiko Ogawa (The University of Aizu), Jun’ichi Haruyama, Makiko Ohtake (JAXA), Tsuneo Matsunaga (NIES), Taro Suzuki, and Takafumi Hayashi (The University of Aizu). WISE-CAPS: An Integrated and Secure Webbased Environment for Analysis and browsing of Lunar and Planetary Data. In Proc. The 41st Lunar and Planetary Science Conference, 2010.
	We are now constructing aWeb-GIS based framework called ‘WISE-CAPS,’ a virtual research environment to share and browse the data under secured data access. This presentation will address on current implementation status and future prospective.
[takafumi-05:2009]	T. Hayashi and S. Matsufuji. A generalized construction of optimal zero-correlation zone sequence set from a perfect sequence. In Signal Design and its Applications in Communications, 2009. IWSDA ’09. Fourth International Workshop on, pages 24–27, Oct. 2009.
	The present paper introduces a new approach to the construction of a sequence set with a zero-correlation zone (ZCZ). This sequence set is referred to as a zerocorrelation zone sequence set. The proposed sequence construction can generate an optimal ZCZ sequence set, the member size of which reaches the theoretical bound. The proposed sequence construction generates a ZCZ sequence set from a perfect sequence and a Hadamard matrix.
[takafumi-06:2009]	S. Matsufuji, T. Matsumoto, T. Hayashida, T. Hayshi, N. Kuroyanagi, and P. Fan. On a ZCZ code including a sequence useful for synchronization. In Signal Design and its Applications in Communications, 2009. IWSDA ’09. Fourth International Workshop on, pages 28–31, Oct. 2009.
	This paper presents a ZCZ code which are combinedly used to spread data and synchronization symbol in quasi-synchronous CDMA systems using PSK, ASK or BFSK. Furthermore a simple matched filter is presented, which calculates simultaneously correlations with arbitrary sequences in the ZCZ code.
[takafumi-07:2009]	Junya Terazono, Noriaki Asada, Hirohide Demura, Naru Hirata (The University of Aizu), Kazuto Saiki (Osaka University), Akira Iwasaki (The University of Tokyo) Ryuichi Oka, Takafumi Hayashi, Taro Suzuki (The University of Aizu), Hideaki Miyamoto (The University of Tokyo), Junichi Haruyama, Makiko Ohtake (JAXA), Tsuneo Matsunaga (NIES), Shinichi Sobue, Hayato Okumura (JAXA), Taketo Fujita, and Aya Yamamoto (RESTEC). Integrated Lunar Web-GIS Environment Using Data Obtained by Lunar Exploration. In Proc. The 40th Lunar and Plaentary Science Conference, 2009.
	The dissemination of Web-GIS (Geographical Information System) in the research field demonstrates that the map, shown in the web pages, are the most basic data for the scientific activity. This fact also have an effect on lunar exploration. In Kaguya project, the handling of huge quantities of data will be the key to promote research. Most of the data are obtaind by LISM, Lunar Imager and Spec-trometer, consists of Multiband Imager (MI), Spectral Profiler (SP) and Terrain Camera (TC). The image data will form the base of the Kaguya data for global mapping and topographical understanding of the moon. The network-based collaboration environment enables them to utilize those image data without carry-ing them on in the meeting and share their result on the net. It will contribute in the increasing of scientific productivity and indurate future style of research in lunar exploration. In this presentation, we will show current imple-mentation status of the Web-GIS based collaboration environment using lunar exploration data.

Unrefereed Papers

[takafumi-08:2009]	H. Fukuhara, I. Koseda, R. Fujita, T. Miyazaki, S. Saito, J. Iwase, and T. Hayashi. A Rapid Construction of a Versatile Cloud Computing System Infrastructure. In Proc. of 2009 Autumn Conf. of International C I O Forum, 2009.
	A novel elastic Cloud Computing Architecture using a virtual structured overlay network, which gives content-aware networking, is proposed. Several application are presented.(in Japanese)
[takafumi-09:2009]	T. Hayashi, H. Fukuhara, I. Koseda, R. Fujita, J. Terazono, T. Miyazaki, J. Iwase, and A. Kara. セSecure Loosely Coupled Integration Infrastructure for Cloud Computing. In Proc. of 2009 Joint Conf. of JSIS and JASI, 2009.
	A novel intelligent infrastructure using network-centric approach and structured overlay network. Application of the proposed scheme to local information infrastructure was presented.(in Japanese)
[takafumi-10:2009]	J. Terazono, H. Fukuhara, M.S aito, T. Miyazaki, S. Saito, J. Iwase, and T. Hayashi. Network-Centric Architecture Intelligent Infrastructure. In Proc. of the 50th IPSJ Annual Conf., 2010.
	A novel network-centric approach for the construction and the maintenance intelligent infrastructure was proposed.(in Japanese)
[takafumi-11:2009]	T. Yamada, K. Suzuki, T. Nihei, J. Terazono, K. Itabashi, H. Hashima, Y. Yabuki, Y. Tannno, H. Fukuhara, K. Shiono, and T. Hayashi. A robust e-learning system using content-aware network. In Proc. of the 50th IPSJ Annual Conf., 2010.
	A novel robust e-learning system using content-aware network is proposed. (in Japanese)

Grants

[sding-04:2009]	S. Ding. Blind source separation using sparse frame representation for multi source signals and its applications, 2008-2010.
	Scientific Research C, No. 20500209, 2008 Grants-In-Aid for Scientific Research, Japan Society for the Plomotion of Science (JSPS)
[takafumi-12:2009]	Takafumi Hayashi. Study of of ternary sequence set having zerocorrelation zone for periodicand Aperiodic correlation functions, 2007-2009.
	Grants-In-Aid for Scientific Research, Japan Society for the Plomotion of Science (JSPS)
[yodai-01:2009]	Yodai Watanabe. Grant-in-Aid for Encouragement of Young Scientists (B) from the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan, 2009-2011.

Academic Activities

[sding-05:2008]	S. Ding, 2009. Review committee member candidate for Grants-In-Aid for Scientific Research projects, JSPS
[sding-06:2009]	S. Ding, 2009. Served as the Program Committee Chair for The 19th Intelligent System Symposium (FAN 2009) and The 1st International Workshop on Aware Computing (IWAC2009)
[sding-07:2009]	S. Ding, 2009. TProgram Committee member of The Fourth International Conference on Innovative Computing, Information and Control (ICICIC 2009)
[sding-08:2009]	S. Ding, 2008. Organizing Committee member of Second International Symposium on Intelligent Informatics (ISII2009)
[sding-09:2009]	S. Ding, 2009. Institute of Electrical and Electronics Engineers (IEEE), Membership.
[sding-10:2009]	S. Ding, 2009. IEEE Signal Processing Society, Membership. Reviewers for the IEEE Transactions on Signal Processing and IEEE Signal Processing Letters
[sding-11:2009]	S. Ding, 2009. IEICE, Membership
[sding-12:2009]	S. Ding, 2009. The Association for Computing Machinery (ACM), Membership
[sding-13:2009]	S. Ding, 2009. The Acoustical Society of America (ASA), Membership
[takafumi-14:2009]	Takafumi Hayashi, 2009. Reviewer of Eletctronics Letters
[takafumi-15:2009]	Takafumi Hayashi, 2009. Program Chair of CIT2009
[takafumi-16:2009]	Takafumi Hayashi, 2009. Reviewer of IEEE Signal Processing Letters
[takafumi-17:2009]	Takafumi Hayashi, 2009. Reviewer of IEEE Communication Letters
[takafumi-18:2009]	Takafumi Hayashi, 2009. Reviewer of ICC
[takafumi-19:2009]	Takafumi Hayashi, 2009. Reviewer of IEICE Transactions
[takafumi-20:2009]	Takafumi Hayashi, 2009. Reviewer of OE Magazine

Patents

[yodai-02:2009]	Wataru Matsumoto and Yodai Watanabe. Quantum key distribution method and communication device Registered United States Patent 7,609,839, October 2009.
[yodai-03:2009]	Wataru Matsumoto and YodaiWatanabe. Quantum key delivery method and communication device Registered Japanese Patent 4290401, April 2009.
[yodai-04:2009]	Wataru Matsumoto and Yodai Watanabe. Quantum key distribution method and communication device Registered Japanese Patent 4346929, July 2009.

Ph.D., Master and Graduation Theses

[sding-14:2009]	Hironori Uchiyama. Master Thesis: Solving the shortest route problem by computer simulation for self-organizing of amoeba, University of Aizu, 2009. Thesis Advisor: Ding, S.
[sding-15:2009]	Hiroyuki Abe. Graduation Thesis: Improving the Wave Convergence in Computer Simulations of the Time Reversal Acoustics, University of Aizu, 2009. Thesis Advisor: Ding, S.
[sding-16:2009]	Takahiro Haneda. Master Thesis: Pseudo Online Independent Component Analysis for Dynamical Mixtures of Non-Stationary Sources, University of Aizu, 2009. Thesis Advisor: Ding, S.
[sding-17:2009]	Keiji Muto. Graduation Thesis: Sparse Representation and Recovery of Non-Sparse Signal, University of Aizu, 2009. Thesis Advisor: Ding, S.
[sding-18:2009]	Noriyuki Takahashi. Graduation Thesis: Online Independent Component Analysis by Maximizing Negentropy Approximated with Two Non-Linear Functions, University of Aizu, 2009. Thesis Advisor: Ding, S.
[sding-19:2009]	Hironori Nihei. Graduation Thesis: Solving Permutation Switching Problem in Online Fast Fixed-Point Independent Component Analysis Algorithm, University of Aizu, 2009. Thesis Advisor: Ding, S.
[takafumi-21:2009]	Yoshinobu Tanno. Graduation Thesis: Efficient Information Management for Information Explosion, University of Aizu, 2009. Thesis Advisor: Takafumi Hayashi
[takafumi-22:2008]	Kana Itabashi. Graduation Thesis: Network-Centric Web Filtering Using a Messaging Network, University of Aizu, 2009. Thesis Advisor: Takafumi Hayashi
[takafumi-23:2009]	Hidemi Takahashi. Graduation Thesis: An E-Local government based on Enterprise Architecture, University of Aizu, 2009. Thesis Advisor: Takafumi Hayashi
[takafumi-24:2009]	Yusei Yabuki. Graduation Thesis: Service Recovery for a Local e-government based on an Intelligent Infrastructure, University of Aizu, 2009. Thesis Advisor: Takafumi Hayashi
[takafumi-25:2009]	Kensuke Tomita. Master Thesis: Content-Aware Networking with Protocol Buffers using Message Mediation, University of Aizu, 2009. Thesis Advisor: Takafumi Hayashi
[takafumi-26:2009]	Yooin Choi. Master Thesis: Social Networking Service for Local e-Governments using Cloud Computing and Content-aware Networking, University of Aizu, 2009. Thesis Advisor: Takafumi Hayashi

Others

[sding-20:2009]

S. Ding. Blind source separation (BSS) and Independent component analysis (ICA)-Prince Shotoku would also be surprised. Japanese Magazine: Fukushima no Shinro, No. 329, pp. 54-57, January 2010. A general introduction for one of my research areas, Blind source separation (BSS) and Independent component analysis (ICA).

2011 THE UNIVERSITY OF AIZU ALL RIGHTS RESERVED