Takafumi Hayashi
Professor
Shuxue Ding
Associate Professor
Yodai Watanabe
Assistant Professor
Zuyuan Yang
Visiting Researcher
|
Takafumi Hayashi Professor |
Shuxue Ding Associate Professor |
Yodai Watanabe Assistant Professor |
Zuyuan Yang Visiting Researcher |
The research and education activities in the laboratory focus on the theoretical foundations of computers and computations, including broad applications in computer science and engineering. Our work covers algorithms and computation, programming languages, discrete mathematics, statistical signal processing, cryptography, 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, xAAS;
Quantum cryptography,
Signal processing;
Image analysis for measurement;
Enterprise Integration and Messaging Network:
Information 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;
Information theory and algorithmic complexity.
smart grid
radar pulse compression
The following combined research is running:
independent component analysis and sequence design.
independent component analysis and network anomaly detection.
distributed data store grids loosely coupled 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.
Z. Yang, G. Zhou, S. Ding, and S. Xie. Nonnegative Blind Source Separation by Iterative Volume Maximization with Fully Nonnegativity Constraints. ICIC Express Letters, 4(6(B)):2329-2334, December 2010.
Nonnegative blind source separation (nBSS) has been widely discussed, due to the attractive real-world applications. Recently, based on the least-correlation of the component, an interesting nBSS method is developed by Wang et al. It is under the assumption that both of the sources and the mixing matrix are nonnegative. However, as only the nonnegativities of the sources are constrained, the estimated mixing matrix cannot be ensured to be nonnegative. In this paper, additional constraints are derived and a method of iterative volume maximization with fully nonnegativity constraints (IVM-FNC) is proposed. The results are more interpretative, while the process is still based on solving the linear programming problem. Numerical experiments with synthetic signals and real images are performed that show the effectiveness of the proposed method.
Z. Yang, S. Ding, and S. Xie. Blind Source Separation by Fully Nonnegative Constrained Iterative Volume Maximization. IEEE Signal Processing Letter, 17(9):799-802, September 2010.
Blind source separation (BSS) has been widely discussed in many real applications. Recently, under the assumption that both of the sources and the mixing matrix are nonnegative, Wang et al. develop an amazing BSS method by using volume maximization. However, the algorithm that they have proposed can guarantee the nonnegativities of the sources only, but cannot obtain a nonnegative mixing matrix necessarily. In this letter, by introducing additional constraints, a method for fully nonnegative constrained iterative volume maximization (FNCIVM) is proposed. The result is with more interpretation, while the algorithm is based on solving a single linear programming problem. Numerical experiments with synthetic signals and real-world images are performed, which show the effectiveness of the proposed method.
Takafumi Hayashi and Shinya Matsufuji. A Generalized Construction of Optimal Zero- Correlation Zone Sequence Set from a Perfect Sequence Pair. IEICE Trans. Fundamentals, E93-A(11):2337-2344, nov 2010.
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.period.
Raymond Wu, Masayuki Hisada adn Atsushi Kara, and Takafumi Hayashi. Event Capture Approaches. pages 330-335, july 2010.
The ever-increasing illegal transaction has resulted in significant impact and become an alert in the service industry. Our research indicates that the semantic violation, which is invisible to the conventional techniques, is the key issue in web security. Existing methods bypass new types of vulnerability as they don't reflect the intermediate process, through a semantic structure, for how the vulnerability is built. Our approach sheds light on semantic gap analysis by capturing the image of state at three different events. It realizes semantic validation through metadata interoperability. It also supports web security for service orientation in modeldriven technologies. To further illustrate event capture, we apply metadata codes, generated from language independent token decomposition, to demonstrate how the semantic metadata impacts the abstract layer in producing semantic gap analysis. As the new type of vulnerability can be precisely specified, business impact can be eliminated.
Shinya Matsufuji, Takahiro Matsumoto, Tomohiro Hayashida, Takafumi Hayashi, Noriyoshi Kuroyanagi, and Pingzhi Fan. On a ZCZ Code Including a Sequence Used for a Synchronization Symbol. IEICE Trans. Fundamentals, E93-A(11):2286-2290, nov 2010.
This paper presents a ZCZ code which are combinedly used for spreading sequences and a synchronization symbol in quasi-synchronous CDMA systems using PSK, ASK or BFSK. Furthermore a simple matched filter is presented, which simultaneously calculates correlations with any sequences in the ZCZ code.
Z. Tang, Z. Yang, and S. Ding. Sparse Representations of Images Via Overcomplete Dictionary Learned by Adaptive Non-Orthogonal Sparsifying Transform. In Proc. The 3rd International Conference on Intelligent Networks and Intelligent Systems (ICINIS 2010), pages 120-123, November 2010.
How to learn an overcomplete dictionary for sparse representations of image is an important topic in machine learning, sparse coding, blind source separation, etc. The so-called K-singular value decomposition (K-SVD) method is powerful for this purpose; however, it is too time-consuming to apply. Recently, an adaptive orthogonal sparsifying transform (AOST) method has been developed to learn the dictionary that is faster. However, the corresponding coefficient matrix may not be as sparse as that of K-SVD. For solving this problem, in this paper, a non-orthogonal iterative match method is proposed to learn the dictionary. By using the approach of sequentially extracting columns of the stacked image blocks, the non-orthogonal atoms of the dictionary are learned adaptively, and the resultant coefficient matrix is sparser. Experiment results show that the proposed method can yield effective dictionaries and the resulting image representation is sparser than AOST.
Z. Yang, G. Zhou, S. Ding, and S. Xie. Blind Source Separation by Nonnegative Matrix Factorization with Minimum-Volume Constraint. In Proc. 2010 International Conference on Intelligent Control and Information Processing (ICICIP2010), pages 117-119, August 2010.
Recently, nonnegative matrix factorization (NMF) attracts more and more attentions for the promising of wide applications. A problem that still remains is that, however, the factors resulted from it may not necessarily be realistically interpretable. Some constraints are usually added to the standard NMF to generate such interpretive results. In this paper, a minimum-volume constrained NMF is proposed and an efficient multiplicative update algorithm is developed based on the natural gradient optimization. The proposed method can be applied to the blind source separation (BSS) problem, a hot topic with many potential applications, especially if the sources are mutually dependent. Simulation results of BSS for images show the superiority of the proposed method.
J. Terazono, H. Fukuhara, I. Koseda, R. Fujita, T. Miyazaki, S. Saito, and T. Hayashi. Service oriented architecture realized by a messaging network. In Network Operations and Management Symposium (NOMS), 2010 IEEE, pages 934-937, apr. 2010.
This paper introduces an approach to realize service-oriented architecture (SOA) governance using a messaging network. The proposed solution uses a messaging network with a structured overlay. The messaging network is XML-based, and is an actual implementation of a content-based network. The proposed scheme provides a network-centric approach to ensure SOA governance by use of a common proactive scheme on the network infrastructure.
Raymond Wu, Masayuki Hisada, Atsushi Kara, and Takafumi Hayashi. Metadata driven approaches for web security of new age computing. In Proceedings of the 2010 International conference on internet computing ICOMP 2010, pages 330-335, july 2010.
Our recent investigation indicated that the existing approaches are unable to cope with web security of next-generation computing, as the attackers have learned to bypass the detection and design new attacking patterns. Conventional methods limit their focus to the physical layer; consequently these methods bypass new types of vulnerability that can cause tremendous business loss. Our novel approach aims to solve the issues by applying decomposition techniques to employ metadata abstract in semantic analysis. It further uses a three-event capture and dual control method to perform the validation process. In consideration of the optimized control and vulnerability rate, SQL injection was taken as an example to demonstrate how the metadata strategy impacts the abstract layer in producing semantic analysis. Our research contributes novel approaches in applying metadata driven approaches to envision the semantic structure. It further favors the service industry in building up the portfolio foundation in component-based design.
T. Hayashi, T. Maeda, and S. Okawa. A Novel Zero-Correlation Zone Sequence Set with Sequence Subsets. In Proc. ISCIT2010, pages 384-388. IEEE, nov. 2010.
The present paper introduces a new approach to the construction of a sequence set with a zero-correlation zone. The proposed sequences can be constructed from a pair of Hadamard matriccs of the orders n0 and n1. The constructed sequence set consists of n0n1 ternary sequences, each of length n0m+1(n1 + 2) for a non negative integer m: The sequence member size of the proposed sequence set is equal to n1(n1 + 2) times that of the theoretical upper bound of the member size of a sequence set with a zero-correlation zone. The proposed sequence set consists of n0 subsets, with each of member size being n1: The correlation function of the sequences of a pair of different subsets, so called inter-subset correlation function, has a zerocorrealtion zone that is almost twice the width of the correlation function of the sequences of the same subset (intra-subset correlation function). This wider intersubset zero-correlation contributes to the performance improvement of applications of the proposed sequence set. The proposed sequence sets have a zero-correlation zone for both periodic and aperiodic corlelation functions.
T. Maeda and T. Hayashi. Parameterization of Perfect Sequences. In Proc. IEEE TENCON 2010, pages 1307-1312, nov. 2010.
A ZCZ(Zero Correlation Zone) sequence set plays an important role in the research of CDMA, ultrasonic imaging, position control and so on. Its a set of perfect sequences which has a property about cross-correlation. We treat the set of perfect sequences as a zero set of quadratic equations and try to simplify these equations. We prove Decomposition Theorem of perfect sequences and the theorem convert the problem of the structures of perfect sequences into the problem of the structures of quasi-perfect sequences which we named. Parameterizing of perfect sequences of easy case and quasi-perfect sequences lead us to the parameterization of perfect sequences of arbitrary length.
T. Maeda and T. Hayashi. A Novel Class of Binary Zero-Correlation Zone Sequence Sets. In Proc. IEEE TENCON 2010, pages 708-711, nov. 2010.
The present paper introduces the construction of binary sequences having a zerocorrelation zone. The cross-correlation function and the side-lobe of the autocorrelation 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 Hadamard matrix of order n. The proposed zerocorrelation zone sequence set consists of two sub groups. The inter-group crosscorrelation function has much wider than the inner-group cross-correlation function. When the proposed sequence set is applied to the synthetic aperture ultrasonic imaging, this wide inter-group zero-correlation zone enables better image than usual method. The proposed sequence set is suitable for real-time synthetic aperture ultrasonic imaging.
Takafumi Hayashi. Real" Cloud" and Medical Information Management. In J-RISM 2010, 2010.
The effect, contribution of cloud system and the requirements for cloud are presented. A cloud for healthcare and medical information system are discussed.
Takao Maeda, Shigeru Kanemoto, and Takafumi Hayashi. Application of Zero Correlation Sequence Set to Ultrasonic Imaging. In IEICE Technical Report US2010 (2010-06), pages 37-40. IEICE, June 2010.
The present paper introduces the construction of binary sequences having a zerocorrelation zone. The crosscorrelation function and the side-lobe of the auto-correlation function of the proposed sequence set is zero for the phase shifts within the zerocorrelation zone. The proposed zero-correlation zone sequence set can be generated from an arbitrary Hadamard matrix of order n. The proposed zero-correlation zone sequence set consists of two sub groups. The inter-group cross-correlation function has much wider than the inner-group cross-correlation function. When the proposed sequence set is applied to the synthetic aperture ultrasonic imaging, this wide inter-group zerocorrelation zone enables better image than usual method. The proposed sequence set is suitable for real-time synthetic aperture ultrasonic imaging.
Takuto Yamada and Kazunori Suzuki and Tomohiro Warashina and Takafumi Hayashi. An Intelligent Infrastructure for Heterogeneous Big Data. In the 51st IPSJ Annual Conference, 2009. An intelligent infrastructure for analysis of heterogeneous big data is proposed.
Takuto Yamada and Kazunori Suzuki and Tomohiro Warashina and Takafumi Hayashi. A healthcare supporting system using a loosely coupled integration of healthcare information and environmental information. In the 51st IPSJ Annual Conference, 2011.
network centric The proposed system uses a network centric approach for a loosely coupled integration of healthcare information and environmental information.
Takafumi Hayashi and Hideyuki Fukuhara and Isamu Koseda and Ryutaro Fujita and Toshiaki Miyazaki and Senro Saito and Jiro Iwase. Coupled Integration of Services using Message Mediation. In 22011 Spring Conference of CIO Forum, 2011.
An approach of an application of message mediation for loosely coupled integration of networks having different policy is proposed.
Ryutaro Ichise and Yodai Watanabe. Contribution Estimation of Authors In The 24th Annual Conference of the Japanese Society for Artificial Intelligence, 2010.
Yodai Watanabe and Ryutaro Ichise. Evaluation of a Method for Contribution Estimation of Authors In IPSJ SIG Technical Reports, 2010-ICS-161, 2010.
S. Ding. Blind source separation using sparse frame representation for multi source signals and its applications, 2008-2010.
This is supported as the project Scientific Research C, No. 20500209, 2008 GrantsIn-Aid for Scientific Research, Ministry of Education, Culture, Sports, Science and Technology, Japan.
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.
Yodai Watanabe. Grant-in-Aid for Encouragement of Young Scientists (B) from the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan, 2006-2008.
Yodai Watanabe. Grant-in-Aid for Encouragement of Young Scientists (B) from the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan, 2003-2005.
S. Ding, 2010.
Review committee member candidate for Grants-In-Aid for Scientific Research projects, JSPS
S. Ding, 2010.
Program Committee member of The Fifth International Conference on Innovative Computing, Information and Control (ICICIC2010)
S. Ding, 2010.
Institute of Electrical and Electronics Engineers (IEEE), Membership.
S. Ding, 2010.
IEICE, Membership
S. Ding, 2010.
The Association for Computing Machinery (ACM), Membership
S. Ding, 2010.
The Acoustical Society of America (ASA), Membership
S. Ding, 2010.
Program Committee member of Third International Symposium on Intelligent Informatics (ISII2010)
S. Ding, 2010.
IEEE Signal Processing Society, Membership. Reviewers for the IEEE Transactions on Signal Processing and IEEE Signal Processing Letters
S. Ding, 2010.
Publicity Committee Chair of 2nd International Symposium on Aware Computing (ISAC 2010)
Takafumi Hayashi, 2010.
Reviewer of IEICE Transactions
Takafumi Hayashi, 2010.
Program Chair of CIT2010
Takafumi Hayashi, 2010.
Reviewer of IEEE Signal Processing Letters
Takafumi Hayashi, 2010.
Reviewer of IEEE Communication Letters
Takafumi Hayashi, 2010.
Reviewer of ICC
Takafumi Hayashi, 2010.
Reviewer of OE Magazine
Takafumi Hayashi, 2010.
Reviewer of Eletctronics Letters
Takafumi Hayashi, 2010.
Program Chair of CIT2010
Wataru Matsumoto and Yodai Watanabe. Quantum key distribution method and communication device Registered Japanese Patent 4346929, July 2009.
Wataru Matsumoto and Yodai Watanabe. Quantum key delivery method and communication device Registered Japanese Patent 4290401, April 2009.
Wataru Matsumoto and Yodai Watanabe. Quantum key distribution method and communication device Registered United States Patent 7,609,839, October 2009.
Yodai Watanabe. Quantum Key Distribution Method, Communication System, and Communication Device Registered Japanese Patent 4231926, December 2008.
Wataru Matsumoto and Yodai Watanabe. Quantum key delivery method and communication device Registered United States Patent 7,461,323, December 2008.
Masakatsu Sato. Graduation Thesis: Generalization of Ant Colony Optimization to 3-Dimensional Space, School of Computer Science and Engineering, March 2011.
Thesis Adviser: S. Ding
Xiqiang Song. Master Thesis: Blind Source Separation Using Temporal Predictability and Applications, Graduate School of Computer Science and Engineering, September 2010.
Thesis Adviser: S. Ding
Takashi Matsushita. Graduation Thesis: Solving the shortest route problem simulating the behavior of amoeba, School of Computer Science and Engineering, March 2011.
Thesis Adviser: S. Ding
Masaki Kurosawa. Graduation Thesis: Reconstruction of signal from its Sparse Coding, School of Computer Science and Engineering, March 2011.
Thesis Adviser: S. Ding
Katsuyuki Nishiguti. Graduation Thesis: Improving Online Independent Component Analysis by Maximizing Negentoropy Approximated with Two Non-Linear Functions and Sparse Representation, School of Computer Science and Engineering, March 2011.
Thesis Adviser: S. Ding
Ryohei Tanaka. Graduation Thesis: Estimation of the Reliability of Message Provided via Twitter, School of Computer Science and Engineering, March 2011.
Thesis Adviser: T. Hayashi
kouji Hashima. Graduation Thesis: Cloud Integration for Operational Efficiency of e-Local Governments in Japan, School of Computer Science and Engineering, March 2011.
Thesis Adviser: T.Hayashi
Mayuko Sakuma. Graduation Thesis: The Threats and Prevention of Malware on Mobile Devices, University of Aizu, 2010.
Thesis Adviser: T. Hayashi
Toshiaki Niehi. Master Thesis: A Presentation System using Emotion Dictionary, University of Aizu, March 2011.
Thesis Adviser: T. Hayashi
Aya Sendoh. Graduation Thesis: Security Reinforcement for Mobile Internet by Independence of Authentication, Authorization and Accounting, University of Aizu, 2010.
Thesis Adviser: T. Hayashi
Ryohei Tanaka. Graduation Thesis: Estimation of the Reliability of Message Provided via Twitter, University of Aizu, 2010.
Thesis Adviser: T. Hayashi
kouji Hashima. Graduation Thesis: Cloud Integration for Operational Efficiency of e-Local Governments in Japan, University of Aizu, 2010.
Thesis Adviser: T.Hayashi
Toshiaki Niehi. Master Thesis: A Presentation System using Emotion Dictionary, University of Aizu, 2010.
Thesis Adviser: T. Hayashi
Aya Sendoh. Graduation Thesis: Security Reinforcement for Mobile Internet by Independence of Authentication, Authorization and Accounting, School of Computer Science and Engineering, March 2011.
Thesis Adviser: T. Hayashi
Takuto Yamada. Master Thesis: An Intelligent Infrastructure with Services for Heterogeneous Data Mining and Mashup, Graduate School of Computer Science and Engineering, March 2011.
Thesis Adviser: T. Hayashi
Kazunori Suzuki. Master Thesis: A Healthcare Support System through the Integration of Environmental and Biological Information, Graduate School of Computer Science and Engineering, March 2011.
Thesis Adviser: T. Hayashi
Mayuko Sakuma. Graduation Thesis: The Threats and Prevention of Malware on Mobile Devices, School of Computer Science and Engineering, March 2011.
Thesis Adviser: T. Hayashi
2011 THE UNIVERSITY OF AIZU ALL RIGHTS RESERVED