• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2006.05a
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• pp.3-6
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• 2006

Methods for risk engineering is a bundle of engineering tools including fundamental concepts and approaches of soft computing with application to real issues of risk management. In this talk fundamental concepts and soft computing approaches of risk engineering will be introduced. As the term of risk implies both advantageous and hazardous uncertainty in its origins, a fundamental theory to describe uncertainties is introduced that includes traditional probability and statistical models, fuzzy systems, as well as less popular modal logic. In particular, modal logic capabilities to express various kinds of uncertainties are emphasized and relations with rough sets and evidence theory are described. Another topic is data mining related to problems in risk management. Some risk mining techniques including fuzzy clustering are introduced and a recently developed algorithm is overviewed. A numerical example is shown.

• Proceedings of the Korean Society for Language and Information Conference
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• 2007.11a
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• pp.42-53
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• 2007

Looking back the history of formal treatment of linguistics, we cannot disregard the contribution of possible world semantics. Intensional logic of Montague semantics, DRT (Discourse Representation Theory), mental space, and situation theory are closely related to or compared with the notion of possible world. All these theories have commonly clarified the structure of belief context or uncertain knowledge, employing hypothesized worlds. In this talk, I firstly brief the pedigree of these theories. Next, I will introduce the recent development of modal logic for the representation of (i) knowledge and belief and (ii) time, in which belief modality is precisely discussed together with the accessibility among possible worlds. I will refer to BDI (belief-desire-intention) logic, CTL (computational tree logic), and sphere-based model in belief revision. Finally, I will discuss how these theories could be applied to the further development of analyses of natural language.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.7 no.2
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• pp.148-153
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• 2007

This paper deals with implementing a steganography based multi-modal biometric system. For this purpose, we construct a multi-biometrics system based on the face and iris recognition. Here, the feature vector of iris pattern is hidden in the face image. The recognition system is designed by the fuzzy-based Linear Discriminant Analysis(LDA), which is an expanded approach of the LDA method combined by the theory of fuzzy sets. Furthermore, we present a watermarking method that can embed iris information into face images. Finally, we show the advantages of the proposed watermarking scheme by computing the ROC curves and make some comparisons recognition rates of watermarked face images with those of original ones. From various experiments, we found that our proposed scheme could be used for establishing efficient and secure multi-modal biometric systems.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.7 no.1
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• pp.71-76
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• 2007

This paper deals with implementing a steganography based multi-modal biometric system. For this purpose, we construct a multi-biometrics system based on the face and iris recognition. Here, the feature vector of iris pattern is hidden in the face image. The recognition system is designed by the fuzzy-based Linear Discriminant Analysis(LDA), which is an expanded approach of the LDA method combined by the theory of fuzzy sets. Furthermore, we present a watermarking method that can embed iris information into face images. Finally, we show the advantages of the proposed watermarking scheme by computing the ROC curves and make some comparisons recognition rates of watermarked face images with those of original ones. From various experiments, we found that our proposed scheme could be used for establishing efficient and secure multi-modal biometric systems.

• Journal of Korea Multimedia Society
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• v.8 no.8
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• pp.1119-1133
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• 2005

As a very important part in development of the protocol, verification and conformance test for protocol specification are complementary techniques that are used to increase the level of confidence in the system functions as prescribed by their specifications. In this paper, we verify the safety and liveness properties of rail signal control protocol type 1 specified in LTS with model checking method, and experimentally prove that it is possible to check for the deadlock, livelock and rechability of the states and actions on LTS. The implemented formal checker is able to verify whether properties expressed in modal logic are true in specifications using modal mu-calculus. We also propose a formal method on generation of conformance test cases using the concept of UIO sequences from verified protocol specification. The suggested tools are implemented by C++ language under Windows NT.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.198-203
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• 2002

A fuzzy logic controller design technique is proposed to apply for the control of flexible system under irregular disturbance. The fuzzy rules of $\ulcorner$Mode Selecting Fuzzy Controller$\lrcorner$ are constructed using displacement, velocity information and modal characteristics of the system. The frequency information of flexible system is picked up from $\ulcorner$Mode Selecting Unit$\lrcorner$ based on Fast-Fourier transform algorithm. Experiment is conducted to verify the proposed theoretical approach, Piezo ceramic and laser accelerometer are used as actuator and sensor in the experiments respectively

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.326.1-326
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• 2002

A fuzzy logic controller design technique is proposed to apply to the control of flexible system under irregular disturbance. The fuzzy rules of $\ulcorner$Mode Selecting Fuzzy Controller$\lrcorner$ are constructed using displacement, velocity information and modal characteristics of the system. The frequency information of flexible system is picked up from $\ulcorner$Mode Selecting Unit$\lrcorner$ based on Fast-Fourier transform algorithm. Experiment is conducted to verify the proposed theoretical approach. (omitted)

• Korean Journal of Logic
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• v.12 no.2
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• pp.1-29
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• 2009

According to Field, mathematical objects do not exist but they might have existed. In this paper I examine how persuasive this 'contingent' nominalism could be. For this I give a detailed analysis of the recent debate on the contingency of mathematical objects. I argue that the putative connection between contingency and explanation could still be sustained, but an independent argument is needed in order to support a general principle underlying the connection. I show that the attacks based on the anti-insularity principles already reflect their own positions on the modal status of the existence of mathematical objects.

• Korean Journal of Logic
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• v.6 no.1
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• pp.33-50
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• 2003

본 논문에서 필자는 기존의 양상 허구주의의 번역 체계가 가지고 있는 세가지 난점을 극복할 수 있는 양상 허구주의의 새로운 번역 체계를 제시한다. 이 세 난점이란 (1) 많은 세계들의 존재를 받아들이지 않을 수 없게 된다. (2) 세계 간의 비교를 하게 하는 양상 진술문을 제대로 번역할 수 없다 (3) 어떤 양상 진술문에 내해 잘못된 진리치를 부여한다 이다. 이 세 난점을 극복하기 위한 필자의 제안은 세계-양화사의 범위 안에 등장하는 양화사들이 주어진 세계 내의 사물들만을 범위 내에 포함하는 루이스의 초기 번역 체계나 비한정적 양회사를 도입하는 루이스의 후기 번역 체계를 받아들이는 대신, 양화사를 조금씩 조금씩 비한정시키는 (unrestrict) 시키는 것이며, 필지 공식 번역 체계는 우주 (세계)의 부분전체론적 합으르 정의되는 "다우주(muitiverse)"라는 새로운 용어를 도입함으로써 얻어진다. 필자의 공식 번역 체계는 다음과 같다: P가 가능하다 iff PW에 의하면 P가 잠인 다우주가 존재한다 P가 필연적으로 참이다 iff PW에 의하면 모든 다우주에서 P가 참이다 마지막으로 필자는 비한정적인 세계 간의 비교를 하게 하는 양상 진술문을 적절하게 번역하기 위해서 필자의 번역 체계에 약간의 수정을 가한다.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.90.3-90
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• 2002

$\textbullet$ Introduction of fuzzy logic controller for dynamic system under irregular disturbance $\textbullet$ Fuzzy rules by displacement information and the frequency characteristics of the system $\textbullet$ Modal analysis for the frequency informations of the system $\textbullet$ Introduction of mode selecting unit(MSU) based on Fast-Fourier transform(FFT) algorithm $\textbullet$ Piezo ceramic as an actuator of flexible structure