Shinya MORITA Satoshi YASUNO Aya MIKI Toshihiro KUGIMIYA
We have studied effects of additive elements into the channel layers of amorphous IGZO TFTs on threshold voltage shift issues under light illumination stress condition. By addition of Hf or Si element, the Vth shift under light illumination and negative bias-temperature stress and illumination stress conditions was drastically suppressed while the switching operation of TFTs using IGZO with Mn or Cu was not observed. It was found that the addition of Si or Hf element into the IGZO channel layer leads to reducing the hole trap sites formed at or near the gate insulator/IGZO channel interface.
Hua Guo ZHANG Qing MOU Hong Shu LIAO Ping WEI
In non-cooperative scenarios, the estimation of direct sequence spread spectrum (DS-SS) signals has to be done in a blind manner. In this letter, we consider the spreading sequence estimation problem for DS-SS signals. First, the maximum likelihood estimate (MLE) of spreading sequence is derived, then a semidefinite relaxation (SDR) approach is proposed to cope with the exponential complexity of performing MLE. Simulation results demonstrate that the proposed approach provides significant performance improvements compared to existing methods, especially in the case of low numbers of data samples and low signal-to-noise ratio (SNR) situations.
Tetsuya ITO Shigeru OGIHARA Yasuhiro HATTORI
In recent years, there has been increasing demand to miniaturize wiring harness connectors in automobiles due to the increasing volume of electronic equipment and so on. With this demand, contact failure caused by the fretting corrosion seems to become a serious problem in the future. In this report, three-dimensional observations using Focused Ion Beam (FIB)-SEM method have been made for tin plated fretting contacts before and after the contact resistance increase with tin plating thickness 5 µm. With these observations, the three dimensional structural transition from tin to tin oxide have been examined.
Raul Ernesto MENENDEZ-MORA Ryutaro ICHISE
An ability to assess similarity lies close to the core of cognition. Its understanding support the comprehension of human success in tasks like problem solving, categorization, memory retrieval, inductive reasoning, etc, and this is the main reason that it is a common research topic. In this paper, we introduce the idea of semantic differences and commonalities between words to the similarity computation process. Five new semantic similarity metrics are obtained after applying this scheme to traditional WordNet-based measures. We also combine the node based similarity measures with a corpus-independent way of computing the information content. In an experimental evaluation of our approach on two standard word pairs datasets, four of the measures outperformed their classical version, while the other performed as well as their unmodified counterparts.
Takeshi FUJISAWA Kiyoto TAKAHATA Takashi TADOKORO Wataru KOBAYASHI Akira OHKI Naoki FUJIWARA Shigeru KANAZAWA Takayuki YAMANAKA Fumiyoshi KANO
High-performance 1.3-µm electroabsorption modulators integrated with DFB lasers are developed for long-reach 100 Gbit Ethernet. The dynamic extinction ratio of over 8-dB with the voltage swing of 2 V are achieved for the four LAN-WDM lanes (14 nm wavelength range) used in 100 Gbit Ethernet with the same modulator structure. The fabricated devices are packaged in butterfly modules and four-lane 40-km single mode fiber transmission at 25-Gbit/s operation is demonstrated. Further, a can-type transmitter optical subassembly is fabricated to reduce the cost and size of transmitter modules. The use of a low-dielectric-constant liquid crystal polymer transmission line makes the 3-dB bandwidth larger and enables 25-Gbit/s operation with CAN-TOSA module.
This paper introduces the ensemble Monte Carlo (EMC) method to study the time behavior of single-electron-based logic gates. The method is then applied to a buffer-inverter gate and the results are examined. An analytical model for time behavior at the low-temperature limit is then introduced and its results are compared with those of the EMC. Finally, a compact model for the delay-error behavior of the buffer gate is introduced.
Most document clustering methods are a challenging issue for improving clustering performance. Document clustering based on semantic features is highly efficient. However, the method sometimes did not successfully cluster some documents, such as highly articulated documents. In order to improve the clustering success of complex documents using semantic features, this paper proposes a document clustering method that uses terms of the condensing document clusters and fuzzy association to efficiently cluster specific documents into meaningful topics based on the document set. The proposed method improves the quality of document clustering because it can extract documents from the perspective of the terms of the cluster topics using semantic features and synonyms, which can also better represent the inherent structure of the document in connection with the document cluster topics. The experimental results demonstrate that the proposed method can achieve better document clustering performance than other methods.
A class of balanced semi-bent functions with an even number of variables is proposed. It is shown that they include one subclass of semi-bent functions with maximum algebraic degrees. Furthermore, an example of semi-bent functions in a small field is given by using the zeros of some Kloosterman sums. Based on the result given by S.Kim et al., an example of infinite families of semi-bent functions is also obtained.
Dengping WEI Ting WANG Ji WANG
With the aim to improve the effectiveness of SAWSDL service discovery, this paper proposes a novel discovery method for SAWSDL services, which is based on the matchmaking of so-called fine-grained data semantics that is defined via sets of atomic elements with built-in data types. The fine-grained data semantics can be obtained by a transformation algorithm that decomposes parameters at message level into a set of atomic elements, considering the characteristics of SAWSDL service structure and semantic annotations. Then, a matchmaking algorithm is proposed for the matching of fine-grained data semantics, which avoids the complex and expensive structural matching at the message level. The fine-grained data semantics is transparent to the specific data structure of message-level parameters, therefore, it can help to match successfully similar Web services with different data structures of parameters. Moreover, a comprehensive measure is proposed by considering together several important components of SAWSDL service descriptions at the same time. Finally, this method is evaluated on SAWSDL service discovery test collection SAWSDL-TC2 and compared with other SAWSDL matchmakers. The experimental results show that our method can improve the effectiveness of SAWSDL service discovery with low average query response time. The results imply that fine-grained parameters fit to represent the data semantics of SAWSDL services, especially when data structures of parameters are not important for semantics.
Peerasak INTARAPAIBOON Ekawit NANTAJEEWARAWAT Thanaruk THEERAMUNKONG
Based on sliding-window rule application and extraction filtering, we present a framework for extracting multi-slot frames describing chemical reactions from Thai free text with unknown target-phrase boundaries. A supervised rule learning algorithm is employed for automatic construction of pattern-based extraction rules from hand-tagged training phrases. A filtering method is devised for removal of incorrect extraction results based on features observed from text portions appearing between adjacent slot fillers in source documents. Extracted reaction frames are represented as concept expressions in description logics and are used as metadata for document indexing. A document knowledge base supporting semantics-based information retrieval is constructed by integrating document metadata with domain-specific ontologies.
Viet Cuong NGUYEN Le Minh NGUYEN Akira SHIMAZU
In the text summarization field, a table-of-contents is a type of indicative summary that is especially suited for locating information in a long document, or a set of documents. It is also a useful summary for a reader to quickly get an overview of the entire contents. The current models for generating a table-of-contents produced relatively low quality output with many meaningless titles, or titles that have no overlapping meaning with the corresponding contents. This problem may be due to the lack of semantic information and topic information in those models. In this research, we propose to integrate supportive knowledge into the learning models to improve the quality of titles in a generated table-of-contents. The supportive knowledge is derived from a hierarchical clustering of words, which is built from a large collection of raw text, and a topic model, which is directly estimated from the training data. The relatively good results of the experiments showed that the semantic and topic information supplied by supportive knowledge have good effects on title generation, and therefore, they help to improve the quality of the generated table-of-contents.
Ken KANEIWA Riichiro MIZOGUCHI
This paper proposes a new semantics that characterizes the time and/or situation dependencies of properties, together with the ontological notion of existential rigidity. For this purpose, we present order-sorted tempo-situational logic (OSTSL) with rigid/anti-rigid sorts and an existential predicate. In this logic, rigid/anti-rigid sorted terms enable the expressions for sortal properties, and temporal and situational operators suitably represent the ontological axioms of existential rigidity and time and/or situation dependencies. A specific semantics of OSTSL adheres to the temporal and situational behaviors of properties based on existential rigidity. As a result, the semantics guarantees that the ontological axioms of properties expressed by sorted tempo-situational formulas are logically valid.
Jeong-Dong KIM Jiseong SON Doo-Kwon BAIK
Metadata registry (MDR) is based on the international standard ISO/IEC 11179. The committee of ISO/IEC JTC 1/SC 32, which had standardized the MDR, has started to improvise the MDR, and the improvised version is named extended MDR (XMDR). However, the XMDR does not fully support the ontology concept, and no method is available for mapping ontology registrations onto registries. To overcome the limitations of the outdated XMDR, this paper proposes an extended XMDR (XMDR+) framework. The XMDR+ framework provides a method for mapping of ontology registrations between the metadata registry and ontologies. To improve the functions of the XMDR, we have proposed herein a framework that is capable of defining a model that manages the relations not only among ontological concepts but also among instances, and guarantees the management and storage of their relationships for supporting valid relations of the ontologies.
Hangkyu KIM Chang-Sup PARK Yoon Joon LEE
Semantic search can be divided into three steps. Keyword matching, the first step, significantly impacts the search results, since the following steps are based on it. In this paper, we propose a keyword matching methodology that aggregates relevance scores of the related text to define the score of an object. Validity of the approach is shown by experiments performed with three public data sets and the detailed analysis of the results.
The Laplacian support vector machine (LSVM) is a semi-supervised framework that uses manifold regularization for learning from labeled and unlabeled data. However, the optimal kernel parameters of LSVM are difficult to obtain. In this paper, we propose a multi-kernel LSVM (MK-LSVM) method using multi-kernel learning formulations in combination with the LSVM. Our learning formulations assume that a set of base kernels are grouped, and employ l2 norm regularization for automatically seeking the optimal linear combination of base kernels. Experimental testing reveals that our method achieves better performance than the LSVM alone using synthetic data, the UCI Machine Learning Repository, and the Caltech database of Generic Object Classification.
Takuya IWANAMI Ayano KIKUCHI Keita HIRAI Toshiya NAKAGUCHI Norimichi TSUMURA Yoichi MIYAKE
Recently enhancing the visual experience of the user has been a new trend for TV displays. This trend comes from the fact that changes of ambient illuminations while viewing a Liquid Crystal Display (LCD) significantly affect human impressions. However, psychological effects caused by the combination of displayed video image and ambient illuminations have not been investigated. In the present research, we clarify the relationship between ambient illuminations and psychological effects while viewing video image displayed on the LCD by using a questionnaire based semantic differential (SD) method and a factor analysis method. Six kinds of video images were displayed under different colors and layouts of illumination conditions and rated by 15 observers. According to the analysis, it became clear that the illumination control around the LCD with displayed video image, the feeling of 'activity' and 'evaluating' were rated higher than the feeling of fluorescent ceiling condition. In particular, simultaneous illumination control around the display and the ceiling enhanced the feeling of 'activity,' and 'evaluating' with keeping 'comfort.' Moreover, the feeling of 'activity' under the illumination control around the LCD and the ceiling condition while viewing music video image was rated clearly higher than that with natural scene video image.
Mohd Hairi HALMI Mohd Yusoff ALIAS Teong Chee CHUAH
A method for estimating channel covariance from the uplink received signal power for downlink transmit precoding in multiple-input multiple-output (MIMO) frequency division duplex (FDD) wireless systems is proposed. Unlike other MIMO precoding schemes, the proposed scheme does not require a feedback channel or pilot symbols, i.e. knowledge of the channel covariance is made available at the downlink transmitter through direct estimation from the uplink received signal power. This leads to low complexity and improved system efficiency. It is shown that the proposed scheme performs better or on par with other practical schemes and only suffers a slight performance degradation when compared with systems with perfect knowledge of the channel covariance.
Yuto HIROSE Itaru NATORI Hisaya SATO Kuniaki TANAKA Hiroaki USUI
Semiconducting polymers, poly(1,4-phenylene) (PPP) and poly(4-diphenylaminostyrene) (PDAS), which are soluble to organic solvents, were synthesized and were deposited by means of electrospray deposition (ESD). The ESD generated spherical shells of diameters ranging from a few to several tens of microns. The shells consisted of coagulation of nanometric particles of the semiconducting polymers. Formation of the shells was largely influenced by the concentration of spray solution. It was also found that the formation of shells can be achieved with various types of soluble polymers.
Yong LEE Kazuyuki NAGATSUMA Kazuhiko HOSOMI Takuma BAN Kazunori SHINODA Koichiro ADACHI Shinji TSUJI Yasunobu MATSUOKA Shigehisa TANAKA Reiko MITA Toshiki SUGAWARA Masahiro AOKI
We fabricated a p-i-n photodiode (PD) with an integrated microlens, and demonstrated its high performance capabilities including high speed (35 GHz), high responsivity (0.8 A/W), and large misalignment tolerance (26 µm), and an error-free 25-Gbit/s 10-km single-mode fiber transmission by using a 100-Gbit/s Ethernet quadplexer receiver module with the PDs.
Soochang PARK Euisin LEE Min-Sook JIN Sang-Ha KIM
In large-scale wireless sensor networks, in order to support group mobility of mobile sinks, this letter proposes a novel strategy for energy-efficient and robust data dissemination to the sinks based on cluster-based communication. The novel strategy is composed of two major mechanisms for reduction of structure construction overhead and routing state maintenance overhead: 1) a virtual infrastructure construction through grid-referred clustering and 2) inter-cluster communication by geographic routing relying on recursive location search. Based on the two major mechanisms, the strategy provides representative location management per sink group, distributed data collection, and per-cluster foot-print chaining in order to effectively adapt the traditional strategy for individual mobile sinks. Simulation results prove the proposed strategy shows better performances in terms of energy efficiency and robustness of data dissemination.