Yuzu Uchida

Non-fragile control for uncertain Takagi-Sugeno fuzzy bilinear systems with delays

The Takagi-Sugeno fuzzy bilinear system is known to be a great tool of describing physical systems and allows representing a wide class of nonlinear systems and hence its control design is important. In practical control, there are chances that malfunction in actuator happens and an uncertain value of the control input may be applied. Hence, controller gain variations should be considered in the control design. In this paper, non-fragile control design, which takes care of uncertainty in control gain, for the Takagi-Sugeno fuzzy bilinear systems with time-varying delays and system uncertainties, is proposed. Conditions for the solvability of the non-fragile control are given in terms of linear matrix inequalities (LMIs).

Output feedback stabilization of Takagi-Sugeno fuzzy bilinear time-delay systems

This paper is concerned with stability analysis and output feedback control design of fuzzy bilinear systems with time-varying delay. First, we consider the stability of the closed-loop systems by assuming a special form of a fuzzy controller. A delay-dependent stability condition, which is less conservative than delay-independent one, is given in terms of linear matrix inequality (LMI). Based on such a stability condition, we propose a state feedback stabilizing control design for fuzzy bilinear systems with time-varying delays. Next, we consider a fuzzy observer design for the same class of systems, and propose an observer design based on another delay-dependent condition. Then, we show that state feedback stabilizing controller and observer make an output feedback stabilizing controller. Finally, we give a numerical example to illustrate our design procedures and to show the effectiveness of our approach.

Output feedback control for discrete-time Takagi-Sugeno fuzzy systems

This paper is concerned with output feedback control design for a discrete-time fuzzy system with immeasurable premise variables. It is well known that Takagi-Sugeno fuzzy model describes a wide class of nonlinear systems especially when its premise variables include immeasurable functions. However, when it comes to control design of such a fuzzy system with immeasurable premise variables, a conventional parallel distributed compensator(PDC) is not feasible because it shares the same premise variables as those of a fuzzy system. In this paper, we introduce an output feedback controller with the estimate of the premise variables of an original fuzzy system. We then formulate the stabilization problem for a discrete-time fuzzy system with immeasurable premise variables. Our control design method is based on a set of strict LMI conditions. No tuning parameter is necessary a priori to solve LMI conditions. Our method includes tuning matrices for control gains in a controller and hence they can be chosen to optimize the control performance of the system. Furthermore, we extend our results to a class of discrete-time fuzzy systems with uncertain parameters. A design method of robust controller for such uncertain systems is also given. Numerical examples are finally given to illustrate our control design method.

Disambiguation of Japanese Onomatopoeias Using Nouns and Verbs

Japanese onomatopoeias are very difficult for machines to recognize and translate into other languages due to their uniqueness. In particular, onomatopoeias that convey several meanings are very confusing for machine translation systems to distinguish and translate correctly. In this paper, we discuss what features are helpful in order to automatically disambiguate the meaning of onomatopoeias that have two different meanings. We used nouns, adjectives, and verbs extracted from sentences as features, then carried out a machine learning classification analysis and compared the accuracy of how well these features differentiate two meanings of ambiguous onomatopoeias. As a result, we discovered that employing a combination of machine learning with nouns and verbs as a feature achieved accuracy of above 80 points. In addition, we were able to improve the accuracy by excluding pronouns and proper nouns and also by limiting verbs to those that are modified by onomatopoeias. In future, we plan to concentrate on dependency between verbs that are modified by onomatopoeia and nouns, as we believe that this approach will help machine translation to translate Japanese onomatopoeias correctly.

Guaranteed Cost Control Design Based on Takagi-Sugeno Fuzzy Systems with Nonlinear Subsystems

This paper is concerned with guaranteed cost control design for a generalized Takagi-Sugeno fuzzy system. The Takagi-Sugeno fuzzy system generally describes nonlinear systems by employing local linear system representations, while a generalized fuzzy system to be considered in this paper describes even a wider class of nonlinear systems by representing locally nonlinear systems. For such a generalized system, a design method of a stabilizing controller with guaranteed cost is proposed by introducing a new class of non-PDC controllers. Non-PDC controller is a generalized controller of PDC one, which is a traditional fuzzy controller. Stabilizing controller design conditions are given in terms of a set of linear matrix inequalities(LMIs), which are easily numerically solvable. A relaxation method is used to reduce the conservatism of design conditions. Finally, numerical examples are given to illustrate our nonlinear control design and to show the effectiveness over other existing results.

Classification of Emotional Onomatopoeias Based on Questionnaire Surveys

Emotion estimation from sentences is helpful in semantic analysis and human-computer interaction. People sometimes express their emotions directly and sometimes describe experiences that produce various emotions. Emotion estimation requires both verbal expressions. We believe Japanese onomatopoeias could serve as a landmark of emotions. In this study, multiple raters judged emotions found in 324 onomatopoeias. We quantitatively evaluated the degree of agreement among the raters and attempted to improve it.

Evaluation of a System for Noun Concepts Acquisition from Utterances about Images (SINCA) Using Daily Conversation Data

For a robot working in an open environment, a task-oriented language capability will not be sufficient. In order to adapt to the environment, such a robot will have to learn language dynamically. We developed a System for Noun Concepts Acquisition from utterances about Images, SINCA in short. It is a language acquisition system without knowledge of grammar and vocabulary, which learns noun concepts from user utterances. We recorded a video of a childs daily life to collect dialogue data that was spoken to and around him. The child is a member of a family consisting of the parents and his sister. We evaluated the performance of SINCA using the collected data. In this paper, we describe the algorithms of SINCA and an evaluation experiment. We work on Japanese language acquisition, however our method can easily be adapted to other languages.

A Web-Based Visualization System for Interdisciplinary Research Using Japanese Local Political Corpus

This paper describes a web-based visualization system, for interdisciplinary research, using the Japanese local political corpus. We illustrate the system for the corpus, which contains the local assembly minutes of 47 Japanese prefectures from April 2011 to March 2015. This four-year period coincides with the office term for assembly members in most local governments. Our system provides full-text search features for utterances, context word extraction using Key Words in Context (KWIC), map visualization, cross-tabulation tables, and political keyword extraction using TF–IDF. We endowed the system with these features to promote its wide range use in various research fields.

Onomatopoeias in the Corpus of Japanese Regional Assembly Minutes: Analysis of the Appearance Tendency and the Word Sense@@@出現傾向と語義の分析

An onomatopoeia is a useful linguistic expression to describe sounds, conditions, degrees and so on. It is said Japanese is rich in onomatopoeic expressions. They are frequently used in daily conversations. The meaning and surface structure of an onomatopoeia varies diachronically. There seem to be regional variations in usage of onomatopoeias. It is necessary to investigate the actual condition of onomatopoeia quantitatively in order to apply onomatopoeias into artificial intelligence. This paper studies practical usages of onomatopoeias in spoken modern Japanese language. To explore Japanese onomatopoeias nowadays, we investigate regional assembly minutes collected from all areas in Japan. The corpus of regional assembly minutes, which has about 300 million words, is the target of the investigation of this study. The minutes of Japanese regional assemblies contain all transcriptions of the utterances in the assemblies. This corpus is suitable for our research since attributes of the speakers are clear and speakers are distributed nation-wide. The first research is about total frequency and regional distribution of onomatopoeias. The onomatopoeias, which represent a request for a promotion of policy, e.g., “shikkari”, “dondon”, are used at high frequency in regional assemblies. There are no remarkable regional differences in frequencies of these onomatopoeias though western Japan has slight higher frequency. The second research is about the meaning of the onomatopoeias. Most of onomatopoeias are polysemous. The meaning of the onomatopoeia differs by context. The authors have manually checked through 10,827 sentences, which contain 153 kinds of onomatopoeia, and then classified the meaning of each onomatopoeic expression. We analyzed for the following subjects: i) ambiguity of onomatopoeic expression, ii) regional differences in meaning, iii) new meanings in modern spoken language, iv) special usage in assemblies, and v) onomatopoeias in the named entities. The third research is about false extraction of onomatopoeias in the morphological analysis. The extraction errors are analyzed from the viewpoint of surface structure and appearance position. In terms of surface structure, it is clear that the word length of an onomatopoeic expression, which has highly false extraction, is shorter. The onomatopoeic expressions, which end with special morae, namely moraic obstruent, moraic nasal and long vowel, have a higher rate of false extraction. In terms of appearance position, dialectal grammar is the main factor causing false extraction. About 25% of false extraction is found in the sentence-closing particles in dialectal grammar. The result of quantitative analysis of the onomatopoeia in modern spoken Japanese language serves as the basic data which contributes to engineering. The results of the analysis in our research are exhibited through the WWW. It is hoped that results will contribute broadly to the practical use of onomatopoeia in the engineering field.

Automatic Post-Editing Method Using Translation Knowledge Based on Intuitive Common Parts Continuum for Statistical Machine Translation

We propose a new post-editing method for statistical machine translation. The method acquires translation rules automatically as translation knowledge from a parallel corpus without depending on linguistic tools. The translation rules, which are acquired based on Intuitive Common Parts Continuum (ICPC), can deal with the correspondence of the global structure of a source sentence and that of a target sentence without requiring linguistic tools. Moreover, it generates better translation results by application of translation rules to translation results obtained through statistical machine translation. The experimentally obtained results underscore the effectiveness of applying the translation rules for statistical machine translation.