IEICE Transactions on Information and Systems
Online ISSN : 1745-1361
Print ISSN : 0916-8532
Volume E103.D , Issue 11
Showing 1-18 articles out of 18 articles from the selected issue
Regular Section
  • Hiroshi MATSUURA
    Type: PAPER
    Subject area: Fundamentals of Information Systems
    2020 Volume E103.D Issue 11 Pages 2250-2261
    Published: November 01, 2020
    Released: November 01, 2020
    JOURNALS FREE ACCESS

    Data aggregation trees in wireless sensor networks (WSNs) are being used for gathering data for various purposes. Especially for the trees within buildings or civil structures, the total amount of energy consumption in a tree must be reduced to save energy. Therefore, the minimum energy-cost aggregation tree (MECAT) and MECAT with relay nodes (MECAT_RN) problems are being discussed to reduce energy consumption in data aggregation trees in WSNs. This paper proposes the tree node switching algorithm (TNSA) that improves on the previous algorithms for the MECAT and MECAT_RN problems in terms of energy efficiency. TNSA repeatedly switches nodes in a tree to reduce the number of packets sent in the tree. Packets are reduced by improving the accommodation efficiency of each packet, in which multiple sensor reports are accommodated. As a result of applying TNSA to MECATs and MECAT-RNs, energy consumption can be reduced significantly with a small burden.

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  • Katsuhisa MARUYAMA, Shinpei HAYASHI, Takayuki OMORI
    Type: PAPER
    Subject area: Software Engineering
    2020 Volume E103.D Issue 11 Pages 2262-2277
    Published: November 01, 2020
    Released: November 01, 2020
    JOURNALS FREE ACCESS

    Recording source code changes comes to be well recognized as an effective means for understanding the evolution of existing software and making its future changes efficient. Therefore, modern integrated development environments (IDEs) tend to employ tools that record fine-grained textual changes of source code. However, there is still no satisfactory tool that accurately records textual changes. We propose ChangeMacroRecorder that automatically and silently records all textual changes of source code and in real time correlates those textual changes with actions causing them while a programmer is writing and modifying it on the Eclipse's Java editor. The improvement with respect to the accuracy of recorded textual changes enables both programmers and researchers to exactly understand how the source code was evolved. This paper presents detailed information on how ChangeMacroRecorder achieves the accurate recording of textual changes and demonstrates how accurate textual changes were recorded in our experiment consisting of nine programming tasks.

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  • Yasunori ISHIHARA, Takashi HAYATA, Toru FUJIWARA
    Type: PAPER
    Subject area: Data Engineering, Web Information Systems
    2020 Volume E103.D Issue 11 Pages 2278-2288
    Published: November 01, 2020
    Released: November 01, 2020
    JOURNALS FREE ACCESS

    This paper discusses a static analysis problem, called absolute consistency problem, for relational schema mappings. A given schema mapping is said to be absolutely consistent if every source instance has a corresponding target instance. Absolute consistency is an important property because it guarantees that data exchange never fails for any source instance. Originally, for XML schema mappings, the absolute consistency problem was defined and its complexity was investigated by Amano et al. However, as far as the authors know, there are no known results for relational schema mappings. In this paper, we focus on relational schema mappings such that both the source and the target schemas have functional dependencies, under the assumption that mapping rules are defined by constant-free tuple-generating dependencies. In this setting, we show that the absolute consistency problem is in coNP. We also show that it is solvable in polynomial time if the tuple-generating dependencies are full and the size of the left-hand side of each functional dependency is bounded by some constant. Finally, we show that the absolute consistency problem is coNP-hard even if the source schema has no functional dependency and the target schema has only one; or each of the source and the target schemas has only one functional dependency such that the size of the left-hand side of the functional dependency is at most two.

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  • Hanan T. Al-AWADHI, Tomoki AONO, Senling WANG, Yoshinobu HIGAMI, Hiros ...
    Type: PAPER
    Subject area: Dependable Computing
    2020 Volume E103.D Issue 11 Pages 2289-2301
    Published: November 01, 2020
    Released: November 01, 2020
    JOURNALS FREE ACCESS

    Multi-cycle Test looks promising a way to reduce the test application time of POST (Power-on Self-Test) for achieving a targeted high fault coverage specified by ISO26262 for testing automotive devices. In this paper, we first analyze the mechanism of Stuck-at Fault Detection Degradation problem in multi-cycle test. Based on the result of our analysis we propose a novel solution named FF-Control Point Insertion technique (FF-CPI) to achieve the reduction of scan-in patterns by multi-cycle test. The FF-CPI technique modifies the captured values of scan Flip-Flops (FFs) during capture operation by directly reversing the value of partial FFs or loading random vectors. The FF-CPI technique enhances the number of detectable stuck-at faults under the capture patterns. The experimental results of ISCAS89 and ITC99 benchmarks validated the effectiveness of FF-CPI technique in scan-in pattern reduction for POST.

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  • Kazuaki KONDO, Takuto FUJIWARA, Yuichi NAKAMURA
    Type: PAPER
    Subject area: Human-computer Interaction
    2020 Volume E103.D Issue 11 Pages 2302-2313
    Published: November 01, 2020
    Released: November 01, 2020
    JOURNALS FREE ACCESS

    When using a gesture-based interface for pointing to targets on a wide screen, displaying a large pointer instead of a typical spot pattern reduces disturbance caused by measurement errors of user's pointing posture. However, it remains unclear why a large pointer helps facilitate easy pointing. To examine this issue, in this study we propose a mathematical model that formulates human pointing motions affected by a large pointer. Our idea is to describe the effect of the large pointer as human visual perception, because the user will perceive the pointer-target distance as being shorter than it actually is. We embedded this scheme, referred to as non-linear distance filter (NDF), into a typical feedback loop model designed to formulate human pointing motions. We also proposed a method to estimate NDF mapping from pointing trajectories, and used it to investigate the applicability of the model under three typical disturbance patterns: small vibration, smooth shift, and step signal. Experimental results demonstrated that the proposed NDF-based model could accurately reproduced actual pointing trajectories, achieving high similarity values of 0.89, 0.97, and 0.91 for the three respective disturbance patterns. The results indicate the applicability of the proposed method. In addition, we confirmed that the obtained NDF mappings suggested rationales for why a large pointer helps facilitate easy pointing.

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  • Takahide ITO, Yuichi NAKAMURA, Kazuaki KONDO, Espen KNOOP, Jonathan RO ...
    Type: PAPER
    Subject area: Human-computer Interaction
    2020 Volume E103.D Issue 11 Pages 2314-2322
    Published: November 01, 2020
    Released: November 01, 2020
    JOURNALS FREE ACCESS

    This paper introduces a novel skin-stretcher device for gently urging head rotation. The device pulls and/or pushes the skin on the user's neck by using servo motors. The user is induced to rotate his/her head based on the sensation caused by the local stretching of skin. This mechanism informs the user when and how much the head rotation is requested; however it does not force head rotation, i.e., it allows the user to ignore the stimuli and to maintain voluntary movements. We implemented a prototype device and analyzed the performance of the skin stretcher as a human-in-the-loop system. Experimental results define its fundamental characteristics, such as input-output gain, settling time, and other dynamic behaviors. Features are analyzed, for example, input-output gain is stable within the same installation condition, but various between users.

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  • Yoshihiro HIROHASHI, Tsuyoshi KATO
    Type: PAPER
    Subject area: Pattern Recognition
    2020 Volume E103.D Issue 11 Pages 2323-2331
    Published: November 01, 2020
    Released: November 01, 2020
    JOURNALS FREE ACCESS

    Currently, the top-k error ratio is one of the primary methods to measure the accuracy of multi-category classification. Top-k multiclass SVM was designed to minimize the empirical risk based on the top-k error ratio. Two SDCA-based algorithms exist for learning the top-k SVM, both of which have several desirable properties for achieving optimization. However, both algorithms suffer from a serious disadvantage, that is, they cannot attain the optimal convergence in most cases owing to their theoretical imperfections. As demonstrated through numerical simulations, if the modified SDCA algorithm is employed, optimal convergence is always achieved, in contrast to the failure of the two existing SDCA-based algorithms. Finally, our analytical results are presented to clarify the significance of these existing algorithms.

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  • Norihide KITAOKA, Eichi SETO, Ryota NISHIMURA
    Type: PAPER
    Subject area: Speech and Hearing
    2020 Volume E103.D Issue 11 Pages 2332-2339
    Published: November 01, 2020
    Released: November 01, 2020
    JOURNALS FREE ACCESS

    We have developed an adaptation method which allows the customization of example-based dialog systems for individual users by applying “plus” and “minus” operations to the distributed representations obtained using the word2vec method. After retrieving user-related profile information from the Web, named entity extraction is applied to the retrieval results. Words with a high term frequency-inverse document frequency (TF-IDF) score are then adopted as user related words. Next, we calculate the similarity between the distrubuted representations of selected user-related words and nouns in the existing example phrases, using word2vec embedding. We then generate phrases adapted to the user by substituting user-related words for highly similar words in the original example phrases. Word2vec also has a special property which allows the arithmetic operations “plus” and “minus” to be applied to distributed word representations. By applying these operations to words used in the original phrases, we are able to determine which user-related words can be used to replace the original words. The user-related words are then substituted to create customized example phrases. We evaluated the naturalness of the generated phrases and found that the system could generate natural phrases.

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  • Takuya KISHIDA, Toru NAKASHIKA
    Type: PAPER
    Subject area: Speech and Hearing
    2020 Volume E103.D Issue 11 Pages 2340-2350
    Published: November 01, 2020
    Released: November 01, 2020
    JOURNALS FREE ACCESS

    This paper proposes a voice conversion (VC) method based on a model that links linguistic and acoustic representations via latent phonological distinctive features. Our method, called speech chain VC, is inspired by the concept of the speech chain, where speech communication consists of a chain of events linking the speaker's brain with the listener's brain. We assume that speaker identity information, which appears in the acoustic level, is embedded in two steps — where phonological information is encoded into articulatory movements (linguistic to physiological) and where articulatory movements generate sound waves (physiological to acoustic). Speech chain VC represents these event links by using an adaptive restricted Boltzmann machine (ARBM) introducing phoneme labels and acoustic features as two classes of visible units and latent phonological distinctive features associated with articulatory movements as hidden units. Subjective evaluation experiments showed that intelligibility of the converted speech significantly improved compared with the conventional ARBM-based method. The speaker-identity conversion quality of the proposed method was comparable to that of a Gaussian mixture model (GMM)-based method. Analyses on the representations of the hidden layer of the speech chain VC model supported that some of the hidden units actually correspond to phonological distinctive features. Final part of this paper proposes approaches to achieve one-shot VC by using the speech chain VC model. Subjective evaluation experiments showed that when a target speaker is the same gender as a source speaker, the proposed methods can achieve one-shot VC based on each single source and target speaker's utterance.

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  • Takayuki NAKATA, Isao NISHIHARA
    Type: PAPER
    Subject area: Image Processing and Video Processing
    2020 Volume E103.D Issue 11 Pages 2351-2361
    Published: November 01, 2020
    Released: November 01, 2020
    JOURNALS FREE ACCESS

    In this paper, we propose an accurate calibration method for glassless stereoscopic systems. The method uses a lenticular lens on a general display. Glassless stereoscopic displays are currently used in many fields; however, accurately adjusting their physical display position is difficult because an accuracy of several microns or one hundredth of a degree is required, particularly given their larger display area. The proposed method enables a dynamic adjustment of the positions of images on the display to match various physical conditions in three-dimensional (3D) displays. In particular, compared with existing approaches, this avoids degradation of the image quality due to the image location on the screen while improving the image quality by local mapping. Moreover, it is shown to decrease the calibration time by performing simultaneous processing for each local area. As a result of the calibration, the offset jitter representing the crosstalk reduces from 14.946 to 8.645 mm. It is shown that high-quality 3D videos can be generated. Finally, we construct a stereoscopic viewing system using a high-resolution display and lenticular lens and produce high-quality 3D images with automatic calibration.

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  • Kento TERAO, Toru TAMAKI, Bisser RAYTCHEV, Kazufumi KANEDA, Shin'ichi ...
    Type: PAPER
    Subject area: Image Recognition, Computer Vision
    2020 Volume E103.D Issue 11 Pages 2362-2370
    Published: November 01, 2020
    Released: November 01, 2020
    JOURNALS FREE ACCESS

    Visual question answering (VQA) is a task of answering a visual question that is a pair of question and image. Some visual questions are ambiguous and some are clear, and it may be appropriate to change the ambiguity of questions from situation to situation. However, this issue has not been addressed by any prior work. We propose a novel task, rephrasing the questions by controlling the ambiguity of the questions. The ambiguity of a visual question is defined by the use of the entropy of the answer distribution predicted by a VQA model. The proposed model rephrases a source question given with an image so that the rephrased question has the ambiguity (or entropy) specified by users. We propose two learning strategies to train the proposed model with the VQA v2 dataset, which has no ambiguity information. We demonstrate the advantage of our approach that can control the ambiguity of the rephrased questions, and an interesting observation that it is harder to increase than to reduce ambiguity.

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  • Hyunyoung LEE, Seungshik KANG
    Type: PAPER
    Subject area: Natural Language Processing
    2020 Volume E103.D Issue 11 Pages 2371-2378
    Published: November 01, 2020
    Released: November 01, 2020
    JOURNALS FREE ACCESS

    Contextual information is a crucial factor in natural language processing tasks such as sequence labeling. Previous studies on contextualized embedding and word embedding have explored the context of word-level tokens in order to obtain useful features of languages. However, unlike it is the case in English, the fundamental task in East Asian languages is related to character-level tokens. In this paper, we propose a contextualized character embedding method using n-gram multi-sequences information with long short-term memory (LSTM). It is hypothesized that contextualized embeddings on multi-sequences in the task help each other deal with long-term contextual information such as the notion of spans and boundaries of segmentation. The analysis shows that the contextualized embedding of bigram character sequences encodes well the notion of spans and boundaries for word segmentation rather than that of unigram character sequences. We find out that the combination of contextualized embeddings from both unigram and bigram character sequences at output layer rather than the input layer of LSTMs improves the performance of word segmentation. The comparison showed that our proposed method outperforms the previous models.

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  • Lisha LIU, Dongjin YU, Dongjing WANG, Fumiyo FUKUMOTO
    Type: PAPER
    Subject area: Biocybernetics, Neurocomputing
    2020 Volume E103.D Issue 11 Pages 2379-2388
    Published: November 01, 2020
    Released: November 01, 2020
    JOURNALS FREE ACCESS

    With the rapid development of scientific research, the number of publications, such as scientific papers and patents, has grown rapidly. It becomes increasingly important to identify those with high quality and great impact from such a large volume of publications. Citation count is one of the well-known indicators of the future impact of the publications. However, how to interpret a large number of uncertain factors of publications as relevant features and utilize them to capture the impact of publications over time is still a challenging problem. This paper presents an approach that effectively leverages a variety of factors with a neural-based citation prediction model. Specifically, the proposed model is based on the Neural Hawkes Process (NHP) with the continuous-time Long Short-Term Memory (cLSTM), which can capture the aging effect and the phenomenon of sleeping beauty more effectively from publication covariates as well as citation counts. The experimental results on two datasets show that the proposed approach outperforms the state-of-the-art baselines. In addition, the contribution of covariates to performance improvement is also verified.

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  • Hiroyuki NISHIMUTA, Daiki NOBAYASHI, Takeshi IKENAGA
    Type: LETTER
    Subject area: Information Network
    2020 Volume E103.D Issue 11 Pages 2389-2393
    Published: November 01, 2020
    Released: November 01, 2020
    JOURNALS FREE ACCESS

    The communications quality of content delivery networks (CDNs), which are geographically distributed networks that have been optimized for content delivery, deteriorates when interflow congestion conditions are severe. Herein, we propose an adaptive server and path switching scheme that is based on the estimated acquisition throughput of each path. We also provide simulation results that show our proposed method can provide higher throughput performance levels than existing methods.

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  • Yujian FENG, Fei WU, Yimu JI, Xiao-Yuan JING, Jian YU
    Type: LETTER
    Subject area: Pattern Recognition
    2020 Volume E103.D Issue 11 Pages 2394-2397
    Published: November 01, 2020
    Released: November 01, 2020
    JOURNALS FREE ACCESS

    Sketch face recognition is to match sketch face images to photo face images. The main challenge of sketch face recognition is learning discriminative feature representations to ensure intra-class compactness and inter-class separability. However, traditional sketch face recognition methods encouraged samples with the same identity to get closer, and samples with different identities to be further, and these methods did not consider the intra-class compactness of samples. In this paper, we propose triplet-margin-center loss to cope with the above problem by combining the triplet loss and center loss. The triplet-margin-center loss can enlarge the distance of inter-class samples and reduce intra-class sample variations simultaneously, and improve intra-class compactness. Moreover, the triplet-margin-center loss applies a hard triplet sample selection strategy. It aims to effectively select hard samples to avoid unstable training phase and slow converges. With our approach, the samples from photos and from sketches taken from the same identity are closer, and samples from photos and sketches come from different identities are further in the projected space. In extensive experiments and comparisons with the state-of-the-art methods, our approach achieves marked improvements in most cases.

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  • Sung-Woon JUNG, Hyuk-Ju KWON, Dong-Min SON, Sung-Hak LEE
    Type: LETTER
    Subject area: Image Processing and Video Processing
    2020 Volume E103.D Issue 11 Pages 2398-2402
    Published: November 01, 2020
    Released: November 01, 2020
    JOURNALS FREE ACCESS

    High dynamic range (HDR) imaging refers to digital image processing that modifies the range of color and contrast to enhance image visibility. To create an HDR image, two or more images that include various information are needed. In order to convert low dynamic range (LDR) images to HDR images, we consider the possibility of using a generative adversarial network (GAN) as an appropriate deep neural network. Deep learning requires a great deal of data in order to build a module, but once the module is created, it is convenient to use. In this paper, we propose a weight map for local luminance based on learning to reconstruct locally tone-mapped images.

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  • Ying TONG, Rui CHEN, Ruiyu LIANG
    Type: LETTER
    Subject area: Image Recognition, Computer Vision
    2020 Volume E103.D Issue 11 Pages 2403-2406
    Published: November 01, 2020
    Released: November 01, 2020
    JOURNALS FREE ACCESS

    LSTM network have shown to outperform in facial expression recognition of video sequence. In view of limited representation ability of single-layer LSTM, a hierarchical attention model with enhanced feature branch is proposed. This new network architecture consists of traditional VGG-16-FACE with enhanced feature branch followed by a cross-layer LSTM. The VGG-16-FACE with enhanced branch extracts the spatial features as well as the cross-layer LSTM extracts the temporal relations between different frames in the video. The proposed method is evaluated on the public emotion databases in subject-independent and cross-database tasks and outperforms state-of-the-art methods.

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  • Toru HIRAOKA
    Type: LETTER
    Subject area: Computer Graphics
    2020 Volume E103.D Issue 11 Pages 2407-2410
    Published: November 01, 2020
    Released: November 01, 2020
    JOURNALS FREE ACCESS

    We propose a nonphotorealistic rendering method for generating checkered pattern images from photographic images. The proposed method is executed by iterative calculation using a Prewitt filter with an expanded window size and can automatically generate checkered patterns according to changes in edges and shade of photographic images. To verify the effectiveness of the proposed method, an experiment was conducted using various photographic images. An additional experiment was conducted to visually confirm the checkered pattern images generated by changing the iteration number, window size, and parameter to emphasize the checkered patterns.

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