Information and Media Technologies
Online ISSN : 1881-0896
ISSN-L : 1881-0896
2 巻 , 2 号
選択された号の論文の21件中1~21を表示しています
Computing
  • Shin-Cheng Mu, Zhenjiang Hu, Masato Takeichi
    2007 年 2 巻 2 号 p. 420-432
    発行日: 2007年
    公開日: 2007/06/15
    ジャーナル フリー
    A transformation from the source data to a target view is said to be bidirectional if, when the target is altered, the transformation somehow induces a way to reflect the changes back to the source, with the updated source satisfying certain healthiness conditions. Several bidirectional transformation languages have been proposed. In this paper, on the other hand, we aim at making existing transformations bidirectional. As a case study we chose the Haskell combinator library, HaXML, and embed it into Inv, a language the authors previously developed to deal with bidirectional updating. With the embedding, existing HaXML transformations gain bidirectionality.
  • Isao Yagi, Yoshiaki Takata, Hiroyuki Seki
    2007 年 2 巻 2 号 p. 433-447
    発行日: 2007年
    公開日: 2007/06/15
    ジャーナル フリー
    Recently, access control for XML database is one of the key issues in database security. Given an access control policy and a query expression, static analysis determines whether the query does not access any elements nor attributes that are prohibited by the policy. In a related work, policies and queries were modeled as regular sets of paths in trees. However, some policies cannot be represented by the model accurately. In this paper, we propose a static analysis method based on tree automata theory. Both a policy and a query are modeled as tree automata, and a policy is provided with two alternative semantics; AND-semantics and OR-semantics. We investigate the computational complexity of the static analysis problem. We show that our query model is sufficiently general by showing that the expressive power of our model is strictly greater than Neven's query automata. We also discuss a consistency problem of policies in schema transformation of XML databases and show that the problem is decidable.
  • Jianwen Xiang, Kazuhiro Ogata, Weiqiang Kong, Kokichi Futatsugi
    2007 年 2 巻 2 号 p. 448-460
    発行日: 2007年
    公開日: 2007/06/15
    ジャーナル フリー
    The aim of this work is to provide a common semantic model for safety analysis and requirements formulation and verification. This paper investigates how the results of one safety analysis technique, fault trees, are interpreted as safety requirements and transformed into formal system specifications written in CafeOBJ, a formal algebraic language. We propose a common semantic model for both formal fault tree analysis and formal system specification by using observational transition systems (OTSs). The method not only can solve the informal problem of traditional fault trees, but more importantly, makes it possible to use the results of fault tree analysis directly, when specifying and verifying the system.
  • Hiroshi Wada, Junichi Suzuki, Katsuya Oba, Shingo Takada, Norihisa Doi
    2007 年 2 巻 2 号 p. 461-472
    発行日: 2007年
    公開日: 2007/06/15
    ジャーナル フリー
    This paper describes and empirically evaluates a new model-driven framework, called Modeling Turnpike (or mTurnpike), which allows developers to effectively model and program domain concepts (ideas and mechanisms specific to a particular business or technology domain). By leveraging UML metamodeling and attribute-oriented programming, mTurnpike provides an abstraction to represent domain concepts at the modeling and programming layers simultaneously. The frontend system of mTurnpike transforms domain concepts between the modeling and programming layers. Its backend system combines domain models and programs, and transforms them to the final (compilable) source code. This paper focuses on the mTurnpike frontend system, and describes its design, implementation and performance implications.
  • Akira Sasaki, Yasuo Oshima, Saeko Kishimoto, Akio Fujimura
    2007 年 2 巻 2 号 p. 473-478
    発行日: 2007年
    公開日: 2007/06/15
    ジャーナル フリー
    We used microarrays to examine individual-based differences in gene expression in primary cultures of renal tubular cells derived from Japanese subjects. The subjects had solitary tumors in the kidney or urinary tract, which were diagnosed pathologically as renal cell carcinoma or transitional cell carcinoma. Renal tissue samples collected from a non-tumorous portion of the tissue were regarded as normal tissues, as there were no abnormal microscopic findings and no evidence of renal dysfunction from the clinical laboratory data. The genome-wide gene expression profiles of nine human renal cell cultures were analyzed using the Affymetrix GeneChip HG-U133A and HG-U133B arrays. Approximately 8, 500 transcripts exhibited significant differential expression (p < 0.05) among the subjects, and the coefficients of variation for 1, 338 transcripts were greater than 50%. Some of these transcripts encode drug-metabolizing enzymes (e.g., UGT1A8 and UGT1A9) or sodium/phosphate cotransporters (e.g., PDZK1). These data provide the basis for toxicogenomic studies using primary cultured renal cortical cells from Japanese subjects.
  • Hiroyuki Sato, Hernán Aguirre, Kiyoshi Tanaka
    2007 年 2 巻 2 号 p. 479-494
    発行日: 2007年
    公開日: 2007/06/15
    ジャーナル フリー
    This paper proposes a method to enhance single population multiobjective evolutionary algorithms (MOEAs) by searching based on local dominance and local recombination. In this method, first, all fitness vectors of individuals are transformed to polar coordinate vectors in objective function space. Then, the population is iteratively divided into several subpopulations by using declination angles. As a result, each sub-population covers a sub-region in the multiobjective space with its individuals located around the same search direction. Next, local dominance is calculated separately for each sub-population after alignment of its principle search direction by rotation. Selection, recombination, and mutation are applied to individuals within each sub-population. The proposed method can improve the performance of MOEAs that use dominance based selection, and can reduce the entire computational cost to calculate dominance among solutions as well. In this paper we verify the effectiveness of the proposed method obtaining Pareto optimal solutions in two representative MOEAs, i.e. NSGA-II and SPEA2, with Multiobjective 0/1 Knapsack Problems.
  • Hiromoto Susawa, Toshihiro Tsuji, Kazumasa Hiramatsu, Takashi Jimbo, T ...
    2007 年 2 巻 2 号 p. 495-505
    発行日: 2007年
    公開日: 2007/06/15
    ジャーナル フリー
    Compositional variation in initial growth was observed in Liquid Phase Epitaxy (LPE) experiments. It is thought that the cause is the flow of the melt which is induced by the slide of the entire melt from the place where there isn't substrate to the substrate before growth. The phenomenon was simulated with a one dimensional model in InGaP growth with a convection term added to a diffusion-limited model. The velocity of flow in the melt was approximated to Stokes's first problem. It was shown that composition of In in grown solid with the flow is larger than that without the flow. In this paper, InGaP LPE growth is considered and a two dimensional model of the flow is used. For the solute transport, a two dimensional model is also adopted except at the growth interface. A result similar to the one dimensional model was obtained. In the two dimensional model, In composition is greater than that in the case without flow for the greater part of the growth time, but decreases when the flow transports dilute solution. This decrease doesn't appear in the one dimensional model. This phenomenon can be explained by considering the influence of the flow on the mole fraction near the boundary layer.
  • Takashi Takenouchi, Masaru Ushijima, Shinto Eguchi
    2007 年 2 巻 2 号 p. 506-513
    発行日: 2007年
    公開日: 2007/06/15
    ジャーナル フリー
    In this paper, we propose GroupAdaBoost which is a variant of AdaBoost for statistical pattern recognition. The objective of the proposed algorithm is to solve the “ p » n ”problem arisen in bioinformatics. In a microarray experiment, gene expressions are observed to extract any specific pattern of gene expressions related to a disease status. Typically, p is the number of investigated genes and n is number of individuals. The ordinary method for predicting the genetic causes of diseases is apt to over-learn from any particular training dataset because of the“ p » n ” problem. We observed that GroupAdaBoost gave a robust performance for cases of the excess number p of genes. In several real datasets which are publicly available from web-pages, we compared the analysis of results among the proposed method and others, and a small scale of simulation study to confirm the validity of the proposed method. Additionally the proposed method effectively worked for the identification of important genes.
  • Tatsuya Akutsu, Hiroki Arimura, Shinichi Shimozono
    2007 年 2 巻 2 号 p. 514-522
    発行日: 2007年
    公開日: 2007/06/15
    ジャーナル フリー
    This paper studies the local multiple alignment problem, which is, given protein or DNA sequences, to locate a region (i.e., a substring) of fixed length from each sequence so that the score determined from the set of regions is optimized. We consider the following scoring schemes: the relative entropy score (i.e., average information content), the sum-of-pairs score and a relative entropy-like score introduced by Li, et al. We prove that multiple local alignment is NP-hard under each of these scoring schemes. In particular, we prove that multiple local alignment is APX-hard under relative entropy scoring. It implies that unless P = NP there is no polynomial time algorithm whose worst case approximation error can be arbitrarily specified(precisely, a polynomial time approximation scheme). Several related theoretical results are also provided.
  • Kou Amano, Hiroaki Ichikawa, Hidemitsu Nakamura, Hisataka Numa, Kaoru ...
    2007 年 2 巻 2 号 p. 523-527
    発行日: 2007年
    公開日: 2007/06/15
    ジャーナル フリー
    Recently, clustering has been recognized as an important and fundamental method that analyzes and classifies large-scale sequence data to provide useful information. We developed a novel clustering method designated as Self-organizing clustering (SOC) that uses oligonucleotide frequencies for large-scale DNA sequence data. We implemented SOC as a command-line program package, and developed a server that provides access to it enabling visualization of the results.SOC effectively and quickly classifies many sequences that have low or no homology to each other. The command-line program is downloadable at http://rgp.nias.affrc.go.jp/programs/. The on-line web site is publicly accessible at http://rgp.nias.affrc.go.jp/SOC/. The common gateway interface (CGI) for the server is also provided within the package.
  • Qamar Uddin Khand, Sumudu Dematapitiya, Sato Saga, Junji Maeda
    2007 年 2 巻 2 号 p. 528-536
    発行日: 2007年
    公開日: 2007/06/15
    ジャーナル フリー
    This paper presents a grid snapping technique, called multi-resolution fuzzy grid snapping (MFGS), that enables automatic mouse cursor snapping for a multi-resolution grid system. Quick and frequent switching between high- and low-resolution grid snapping is essential to make geometrical drawings that include both fine and coarse structures when using CAD systems with ordinary single-resolution grid systems. MFGS is intended to relieve users of this tedious manual switching. MFGS dynamically selects an appropriate snapping resolution level from a multi-resolution grid system according to the pointing behavior of the user. MFGS even supports an extremely fine grid resolution level, which is referred to as the no-snapping level. We show experimental results which demonstrate that MFGS is an effective grid snapping technique that speeds up low-resolution grid snapping while retaining the ability to snap to high-resolution grids. Furthermore, we examine the role of fuzziness in MFGS and its effect on snapping performance.
  • Daisuke Kimura
    2007 年 2 巻 2 号 p. 537-573
    発行日: 2007年
    公開日: 2007/06/15
    ジャーナル フリー
    Wadler proposed the dual calculus, which corresponds to classical sequent calculus LK, and studied the relationship between the λμ-calculus and the dual calculus as equational systems to explain the duality between call-by-value and call-by-name in a purely syntactical way. Wadler left an open question whether one can obtain similar results by replacing the equations with reductions. This paper gives one answer to his question. We first refine the λμ-calculus as reduction systems by reformulating sum types and omitting problematic reduction rules that are not simulated by reductions of the dual calculus. Secondly, we give translations between the call-by-name λμ-calculus and the call-by-name dual calculus, and show that they preserve the call-by-name reductions. We also show that the compositions of these translations become identity maps up to the call-by-name reductions. We also give translations for the call-by-value systems, and show that they satisfy properties similar to the call-by-name translations. Thirdly, we introduce translations between the call-by-value λμ-calculus and the call-by-name one by composing the above translations with duality on the dual calculus. We finally obtain results corresponding to Wadler's, but our results are based on reductions.
Media (processing) and Interaction
  • Yukihito Sakai, Shuji Hashimoto
    2007 年 2 巻 2 号 p. 574-591
    発行日: 2007年
    公開日: 2007/06/15
    ジャーナル フリー
    We have developed an interactive visualization system that enables people to both experience and intuitively understand 4-D space. We proposed a framework in which people can visualize 4-D space using 5-D homogeneous processing. This way of processing uses 5×5 matrices to express various types of transformations and simplifies geometric operations without using any division operations. Therefore, the proposed method improved the system's reliability. We also constructed an interactive environment that associates the user's 3-D position with a 4-D eye point that lies on a 4-D spherical surface surrounding a 4-D solid. The system is composed of a glasses-free 3-D display, a controller pad, and a personal computer. In this environment, we were able to smoothly observe a 4-D solid from an arbitrary 4-D eye point and direction.
  • Yoshinao Takemae, Takehiko Ohno, Ikuo Yoda, Shinji Ozawa
    2007 年 2 巻 2 号 p. 592-600
    発行日: 2007年
    公開日: 2007/06/15
    ジャーナル フリー
    This paper presents a method for automatically estimating human interruptibility in the home environment. To make online remote communication smoother, determining if it is appropriate to interrupt the remote partner is critical. As a first step in achieving this goal, several audio-visual features, extracted from data streams captured by a camera and a microphone, are correlated to human assessments of own interruptibility. Based on these features, the level of interruptibility is estimated using the trained Support Vector Regression (SVR) technique. Finally, we discuss the potential of our method based on the results of several experiments.
  • Kazuyoshi Yoshii, Masataka Goto, Kazunori Komatani, Tetsuya Ogata, Hir ...
    2007 年 2 巻 2 号 p. 601-611
    発行日: 2007年
    公開日: 2007/06/15
    ジャーナル フリー
    This paper presents a highly functional audio player, called Drumix, that allows a listener to control the volume, timbre, and rhythmic patterns (drum patterns)of bass and snare drums within existing audio recordings in real time. A demand for active music listening has recently emerged. If the drum parts of popular songs could be manipulated, listeners could have new musical experiences by freely changing their impressions of the pieces (e.g., making the drum performance more energetic)instead of passively listening to them. To achieve this, Drumix provides three functions for rearranging drum parts, i.e., a volume control function that enables users to cut or boost the volume of each drum with a drum-specific volume slider, a timbre change function that allows them to replace the original timbre of each drum with another selected from a drop-down list, and a drum-pattern editing function that enables them to edit repetitive patterns of drum onsets on a graphical representation of their scores. Special musical skills are not required to use these functions. Subjective experiments revealed that Drumix could add a new dimension to the way listeners experience music.
  • Ayu Purwarianti, Masatoshi Tsuchiya, Seiichi Nakagawa
    2007 年 2 巻 2 号 p. 612-640
    発行日: 2007年
    公開日: 2007/06/15
    ジャーナル フリー
    We propose a query transitive translation system of a CLIR (Cross Language Information Retrieval) for a source language with a poor data resource. Our research aim is to do the transitive translation with a minimum data resource of the source language (Indonesian) and exploit the data resource of the target language (Japanese). We did two kinds of translation, a pure transitive translation and a combination of direct and transitive translations. In the transitive translation, English is used as the pivot language. The translation consists of two main steps. The first is a keyword translation process which attempts to make a translation based on available resources. The keyword translation process involves many target language resources such as the Japanese proper name dictionary and English-Japanese (pivot-target language) bilingual dictionary. The second step is a process to select some of the best available translations. We combined the mutual information score (computed from target language corpus) and TF × IDF score in order to select the best translation. The result on NTCIR 3 (NII-NACSIS Test Collection for IR Systems) Web Retrieval Task showed that the translation method achieved a higher IR score than the machine translation (using Kataku (Indonesian-English) and Babelfish/Excite (English-Japanese) engines). The transitive translation achieved about 38% of the monolingual retrieval, and the combination of direct and transitive translation achieved about 49% of the monolingual retrieval which is comparable to the English-Japanese IR task.
Computer Networks and Broadcasting
  • Takuo Nakashima
    2007 年 2 巻 2 号 p. 641-649
    発行日: 2007年
    公開日: 2007/06/15
    ジャーナル フリー
    Providing quality of service (QoS) in a business environment requires accurate estimation of Internet traffic, especially HTTP traffic. HTTP traffic, mainly consisting of file transmission traffic, depends on the sizes of files with a heavy-tailed property. Analyzing the performance of specific Web servers and comparing server performance is important in QoS provisioning for user applications. In this paper, we present the experimental analysis of Web server performance using our active measurement. We capture activity data from 1984 diverse Web servers by sending measurement packets 20 times in order to evaluate the spatial properties, and we select 14 Web servers to send packets 2, 000 times in 5-second intervals to evaluate the temporal properties. The main contribution of our study is to provide methods of evaluating the temporal and spatial properties on any Web server by measuring from a remote observation host, and to illustrate the current activity of temporal and spatial properties in a series of figures. Crovella's well known work merely describes the self-similar properties for the total transmission time generated by a heavy-tailed file size distribution. We divided the total transmission time into network and server system dependable elements, of which the heavy-tailed properties are captured. We found that temporal properties consist of two factors: stability and activity in the Poisson process. Robustness of heavy-tailedness in terms of constructing elements of total transmission time was evident from the analysis of spatial properties. Finally, we observed the upper boundary and classified groups in a mean-variance plot of primitive elements of the Web server.
  • Jing Cai, Tsutomu Terada, Takahiro Hara, Shojiro Nishio
    2007 年 2 巻 2 号 p. 650-661
    発行日: 2007年
    公開日: 2007/06/15
    ジャーナル フリー
    Recent advances in computer and wireless communication technologies have increased interest in combinations of various techniques such as pull-based data dissemination, data broadcasting, and data caching, as well as investigations into data management in hybrid data delivery systems. This paper proposes cooperative data management based on the Hybrid Wireless Broadcast (HWB) model to provide more efficient data delivery to mobile clients. Our cooperative strategy integrates broadcast scheduling with cache management of the base station, taking heterogeneous and homogeneous access of clients into consideration, by making effective use of HWB data dissemination, i.e., push-based broadcast, pull-based broadcast, and pull-based point-to-point wireless communication. Our simulation results confirmed that the strategy we propose can improve the performance of the system even further.
  • Arjan Durresi, Leonard Barolli, Raj Jain, Makoto Takizawa
    2007 年 2 巻 2 号 p. 662-674
    発行日: 2007年
    公開日: 2007/06/15
    ジャーナル フリー
    Congestion remains one of the main obstacles to the Quality of Service (QoS) on the Internet. We think that a good solution to Internet congestion should optimally combine congestion signaling from network and source reaction, with the following as its main goals: minimum losses and delays, maximum network utilization, fairness among flows, and last but not least, scalability of the solution. The solution should not significantly increase the complexity of router operations. In this paper, we present a new traffic management scheme based on an enhanced Explicit Congestion Notification (ECN) mechanism. Our Multilevel ECN (MECN) conveys more accurate feedback information about the network congestion status than the current ECN. We have designed a TCP source reaction that takes advantage of the extra information provided about congestion. Therefore, MECN responds better to congestion by allowing the system to reach the stability point faster, which results in better network performance. We use control theoretical tools verified by ns 2 simulations to show that MECN can outperform up to twenty times in term of throughput the de facto standard RED/ECN.
  • Shintaro Ueda, Hiroshi Shigeno, Ken-ichi Okada
    2007 年 2 巻 2 号 p. 675-683
    発行日: 2007年
    公開日: 2007/06/15
    ジャーナル フリー
    The new video coding standard H.264/AVC offers major improvements in the coding efficiency and flexible mapping to transport layers. It consists of a video coding layer (VCL) and a network abstraction layer(NAL). The VCL carries out the coding, and the NAL encapsulates data from the VCL in a manner where transmission over a broad variety of transport layers is readily enabled. Since no security features are offered, an authentication scheme to authenticate the sender and data integrity is needed. In this paper we propose SANAL, a stream authentication scheme for H.264/AVC. Unlike existing schemes that carry out authentication procedures at the packet level, authentication procedures in SANAL are carried out at the NAL level. This makes it possible to set priorities to H.264/AVC-specific data without interfering with the H.264/AVC features. We implemented a SANAL prototype and carried out comparative evaluations on playout rate, communication overhead, and process load. The evaluation results show that the playout rate is improved by 40% compared to existing schemes.
Information Systems and Applications
  • Lei Jing, Zixue Cheng, Mizuo Kansen, Tongjun Huang, Shengguo Sun
    2007 年 2 巻 2 号 p. 684-694
    発行日: 2007年
    公開日: 2007/06/15
    ジャーナル フリー
    Embedding educational functions into devices in the everyday environment is an important task for advocates of ubiquitous learning. In this paper, we discuss how to add a reminder service to a schoolbag. An educational function would be added to the device to help pupils remember belongings. Reminding oneself of things is a difficult task and reminder services have been an important subject of computer applications. However, most reminding tools are used for business, not education. Most such services use PDAs as terminals and require the user to create the reminder list by him or herself, making it too complex for some pupils to use. The systems also seldom pay attention to helping users learn how to avoid forgetting. In this research, a ubiquitous learning support system that makes use of schoolbags is presented to assist pupils in managing their personal items. With RFID and infrared sensors, a microcontroller embedded in a schoolbag can monitor what has been put in or taken out of the schoolbag and automatically maintain a schoolbag's items list. Such a bag also enables teachers to make up a schedule that specifies required items for given days. The microcontroller then compares the schedule with the items list in the schoolbag and provides a reminder service for the pupil. In addition to the reminder service, which is based on principles of behavior modification, the paper also proposes a series of methods to help pupils form good personal management habits and reduce their dependence on outside machines.
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