• Title/Summary/Keyword: CRITIC method

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Time-varying Proportional Navigation Guidance using Deep Reinforcement Learning (심층 강화학습을 이용한 시변 비례 항법 유도 기법)

  • Chae, Hyeok-Joo;Lee, Daniel;Park, Su-Jeong;Choi, Han-Lim;Park, Han-Sol;An, Kyeong-Soo
    • Journal of the Korea Institute of Military Science and Technology
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    • v.23 no.4
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    • pp.399-406
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    • 2020
  • In this paper, we propose a time-varying proportional navigation guidance law that determines the proportional navigation gain in real-time according to the operating situation. When intercepting a target, an unidentified evasion strategy causes a loss of optimality. To compensate for this problem, proper proportional navigation gain is derived at every time step by solving an optimal control problem with the inferred evader's strategy. Recently, deep reinforcement learning algorithms are introduced to deal with complex optimal control problem efficiently. We adapt the actor-critic method to build a proportional navigation gain network and the network is trained by the Proximal Policy Optimization(PPO) algorithm to learn an evasion strategy of the target. Numerical experiments show the effectiveness and optimality of the proposed method.

A Study on the Characteristic of Raumplan based on the Architectural Thought of Adolf Loos (아돌프 로스의 건축사상에 기초한 라움플란의 특성에 관한 연구)

  • Park, Chan-Il
    • Korean Institute of Interior Design Journal
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    • v.17 no.6
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    • pp.30-40
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    • 2008
  • Adolf Loos showed important directionality in the thought of modem culture and architecture. The thought about the architecture of Adolf Loos was gathered by "Raumplan". It is the solution of the plan in space. But the concept and method of the "Raumplan" had not been synthesized until near the end of Loos's life. Loos's first reference to the "Raumplan" appears in 1929. I think that "Raumplan" became the solution of the plan in space with a formation process of the thought about the architecture and culture of Adolf Loos. Therefore, the purpose of this paper derived a characteristic of "Raumplan" from the relations between the architectural thought of Adolf Loos and "Raumplan". The processes of the study are as follows. (1)Consideration about the growth background of Adolf Loos and the social situation of Vienna. (2)Analysis about architecture and the cultural critic of Adolf Loos. (3)Analysis of "Raumplan" based on architectural thought of Adolf Loos. As a result, I got the four characteristics of "Raumplan" as follows. (1) Separation and continuation of "Raum". (2) Fragment of "Raum". (3) Overlay and transmission by the axis of multiplex eyes. (4) Structural adjustment of the "Raum" by Hierarchy. Finally, I understood the architecture which Adolf Loos pursued in "Raumplan" had a high function and contained the clear meaning and contents which had practical use and economic value, and it were not a results of the simple logic.

Theory bulding in library and information science based on research method analysis (연구방법론 분석에 의한 문헌정보학 이론개발에 관한 연구)

  • 정동열
    • Journal of the Korean Society for information Management
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    • v.10 no.2
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    • pp.23-41
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    • 1993
  • L~brary and ~nformat~on sclence has been critic~zed for its dearth of conceptually framed, creative research which has been narrowly faused, fragmented. and desgned to solve s~tuational problems. Durmg recent years. a crit~cal concern of scholars in the l~brary and information proiessions has been a need for creative research. Research is the critical element for developing a theoret~cal base in wh~ch to enhance prxtlce of the profess~on and to gu~de ~ t s future development. The purpose of thls paper are to ( 1 1 delineate various levels of theory with implications for research methods. and (2) analyze research methods and contents of prevlous research publ~shtd In Korea durmg last two decades. and ( 3 ) purpose several d~rections toward theory building in vlew of both theoretical and operat~onal aspects.

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Backstepping Sliding Mode-based Model-free Control of Electro-hydraulic Systems

  • Truong, Hoai-Vu-Anh;Trinh, Hoai-An;Ahn, Kyoung-Kwan
    • Journal of Drive and Control
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    • v.19 no.1
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    • pp.51-61
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    • 2022
  • This paper presents a model-free system based on a framework of a backstepping sliding mode control (BSMC) with a radial basis function neural network (RBFNN) and adaptive mechanism for electro-hydraulic systems (EHSs). First, an EHS mathematical model was dedicatedly derived to understand the system behavior. Based on the system structure, BSMC was employed to satisfy the output performance. Due to the highly nonlinear characteristics and the presence of parametric uncertainties, a model-free approximator based on an RBFNN was developed to compensate for the EHS dynamics, thus addressing the difficulty in the requirement of system information. Adaptive laws based on the actor-critic neural network (ACNN) were implemented to suppress the existing error in the approximation and satisfy system qualification. The stability of the closed-loop system was theoretically proven by the Lyapunov function. To evaluate the effectiveness of the proposed algorithm, proportional-integrated-derivative (PID) and improved PID with ACNN (ACPID), which are considered two complete model-free methods, and adaptive backstepping sliding mode control, considered an ideal model-based method with the same adaptive laws, were used as two benchmark control strategies in a comparative simulation. The simulated results validated the superiority of the proposed algorithm in achieving nearly the same performance as the ideal adaptive BSMC.

A Study on the Expressional Characteristics and Kengo Kuma's Structure of Architectural Thinking as the Dynamic Criticism (쿠마켄고의 역동적 비평성으로서의 건축적 사고구조와 표현 특성에 관한 연구)

  • Kim, Yun-Jung;Park, Chan-Il
    • Korean Institute of Interior Design Journal
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    • v.22 no.5
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    • pp.114-125
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    • 2013
  • Kengo Kuma used to be very known well as a critic before being an architect. He usually mentioned quite unique type of comments for subjects whenever his criticism, also even his works results have been able to be targets of criticism materials by his method. His works are the achievements of challenges based on his continuous dynamic criticism. Hence, to have well understanding of his architectural thinking and works result, his complexes criticism structure must be needed to understand. And also, this study is using 'KJ Method' type to analyze his architectural thinking which is complicated making by a type of non-linear. Kengo Kuma's structures of architectural thinking and critiques perspective of modern architecture have been created by 'KJ Method'. Critiques types of keywords and consequences words collected from among the local dedicated professional architecture books to get this research result. First of all, Kengo Kuma desired even modern architecture problems to be melt as a specific architecture result such as modern type of power structure. To have result, Kengo Kuma had experienced sensible activity through materials which have specific characteristic. Also place of materiality created to get relationship between environments and architecture. Secondly, he wanted to recover troubled traditional Japanese architectural perspective which blocked relationship by dichotomy as a right way. In conclusion, this research reaches Kengo Kuma's type of architecture which strongly emphasizes harmony among related components such as human being, materials, substances based on accepted natural environments and lives' principle. Also, much more specific methods have been derived by related works results analyzing which have similar characteristic as Kengo Kuma's one.

A Study of Reinforcement Learning-based Cyber Attack Prediction using Network Attack Simulator (NASim) (네트워크 공격 시뮬레이터를 이용한 강화학습 기반 사이버 공격 예측 연구)

  • Bum-Sok Kim;Jung-Hyun Kim;Min-Suk Kim
    • Journal of the Semiconductor & Display Technology
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    • v.22 no.3
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    • pp.112-118
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    • 2023
  • As technology advances, the need for enhanced preparedness against cyber-attacks becomes an increasingly critical problem. Therefore, it is imperative to consider various circumstances and to prepare for cyber-attack strategic technology. This paper proposes a method to solve network security problems by applying reinforcement learning to cyber-security. In general, traditional static cyber-security methods have difficulty effectively responding to modern dynamic attack patterns. To address this, we implement cyber-attack scenarios such as 'Tiny Alpha' and 'Small Alpha' and evaluate the performance of various reinforcement learning methods using Network Attack Simulator, which is a cyber-attack simulation environment based on the gymnasium (formerly Open AI gym) interface. In addition, we experimented with different RL algorithms such as value-based methods (Q-Learning, Deep-Q-Network, and Double Deep-Q-Network) and policy-based methods (Actor-Critic). As a result, we observed that value-based methods with discrete action spaces consistently outperformed policy-based methods with continuous action spaces, demonstrating a performance difference ranging from a minimum of 20.9% to a maximum of 53.2%. This result shows that the scheme not only suggests opportunities for enhancing cybersecurity strategies, but also indicates potential applications in cyber-security education and system validation across a large number of domains such as military, government, and corporate sectors.

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Layout Principles of Renaissance Classicism Architectural Style and Its Application on Modern Fashion Design - Focused on Classic Style Fashion after the Year 1999 - (르네상스 고전주의 건축양식의 조형원리와 현대패션디자인에의 적용 - 1999년 이후 클래식 스타일 패션을 중심으로 -)

  • Lee, Shin-Young
    • The Research Journal of the Costume Culture
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    • v.18 no.2
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    • pp.261-276
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    • 2010
  • The analysis of an art trend in the principle dimension starts by observing the object of work in the perspective of formative composition and recognizing it as a universal system. It can be said that it is consistent with an interpretation method for a form theory of formal history by Heinrich W$\ddot{o}$lfflin, a leading form critic in art criticism. Hence, the purpose of this study was to find out what are the formative principles in Renaissance Classicism as a design principle to be applicable to modern fashion by reviewing the formative characteristics of Renaissance Classicism Architecture with which W$\ddot{o}$lfflin directly dealt. As for the theoretical literature review, I used W$\ddot{o}$lfflin's theoretical framework and looked at the Renaissance Classicism Architecture that he studied and examined the possibility of utilizing his theory as a layout principle and the characteristics. As for analysis of design cases, I applied the aforementioned architecture layout principle to modern fashion and conducted case study analysis to delve into distinctive layout principles found in fashion. The study showed that the Renaissance Classicism Architectural Style is marked by linearity, planarity, closing and multiple unity: linearity was expressed in the observation form in fixed frontal view and an emphasis on a tangible silhouette homeogenous and definite line structures; planarity was achieved in the form of paralleled layers of frontal view element, planarity style, and identical and proportional repetition of various sizes.; closing signified the pursuit of complete and clear regularity, and architecture developed in a constructive phase through organizational inevitability and absolute invariability.; multiple unity was expressed in self-completedness and independent parallel of discrete forms and harmony of emphasized individual elements in a totality. Applying these layout characteristics of the Renaissance Classicism Architectural style and to see their individual expressive features, I found out that in adopting layout principles of the Renaissance Classicism Architecture to modern fashion, it turned out to be an emphasis of individual silhouettes, a flattened space, completed objects, organic harmony among independent parts: the emphasis of individual silhouettes was expressed in individual definitiveness of formative lines of clothes in accordance with body joints and an emphasis on formative lines of clothes; the flattened space was marked by single layer structure, planarity of elements of clothes, and listing arrangement by appropriate proportion.; the completedness of the objects was expressed by the stationary state where overall image is fixed, the construction of homogeneous and complete space, and absolute inevitability of internal layout in proportion; lastly, organic harmony of independent parts was stressed in independent completedness of each detail, and organic harmony of the whole. The expressive features would lead to a unique expression style of linear emphasis, proportion, constructive forms, and two-dimensional arrangement. The meaning of this study is follows: The characteristics of art school of thought are given shape by appling & analysing the architectural layout principles of historical art school of thought to modern fashion in the view point of formal construction dimension. The applied possibility of historical art school of thought as the source of inspiration about the fashion design is extended.

The Approaches of Cultural Studies to Theatre -The Limits of Theory Application- (연극에 대한 문화연구적 접근 -'이론' 도입의 한계를 중심으로-)

  • Kim, Yongn Soo
    • Journal of Korean Theatre Studies Association
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    • no.40
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    • pp.307-344
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    • 2010
  • Cultural Studies built on the critical mind of New Left exposes the relationship between culture and power, and investigates how this relationship develops the cultural convention. It has achieved the new perspective that could make us to think culture and art in terms of political correctness. However, the critical voices against the theoretical premises of Cultural Studies have been increased as its heyday in 1980s was nearly over. For instance, Terry Eagleton, a former Marxist literary critic, declared in 2003 that the golden age of cultural theory is long past. This essay, therefore, intends to show the weak foundations on which the approaches of cultural studies to theatre rest and to clarify the general problem of their introduction to theatre studies. The approach of cultural studies to theatre takes the form of 'top-down inquiry' as it applies a theory to a particular play or historical period. In other word, from the theory the writer moves to the particular case. The result is not an inquiry but rather a demonstration. This circularity can destroy the point of serious intellectual investigation as the theory dictates answers. The goal-oriented narrow viewpoint as a logical consequence of 'top-down inquiry' makes the researcher to favor the plays or the parts of a play that are proper to test a theory. As a result it loses the fair judgment on the artistic value of a play, and brings about the misinterpretation. The interpreter-oriented reading is the other defect of cultural studies as it disregards the inherent meaning of the text, distorting a play. The approach of cultural studies also consists of a conventionality as it arrives at a stereotyped interpretation by using certain conventions of reasoning and rhetoric. The cultural theories are fundamentally the 'outside theories' that seek to explain not theatre but the very broad features of society and politics. Consequently their application to theatre risks the destructive criticism, disregarding the inherent experience of theatre. Most of, if not all, cultural theories, furthermore, are proven to be lack of empirical basis. The alternative method to them is a 'cognitive science' that proves scientifically our mind being influenced by bodily experience. The application of cultural materialism to Shakespeare's is one of the cases that reveal the limits of cultural studies. Jonathan Dollimore and Water Cohen provide a kind of 'canonical study' in this application that is imitated by the succeeding researchers. As a result the interpretation of has been flooded with repetitive critical remarks, revealing the problem of 'top-down inquiry' and conventional reasoning. Cultural Studies is antipodal to theatre in some respect. It is interested chiefly in the social and political reality while theatre aims to create the fiction world. The theatre studies, therefore, may have to risk the danger of destroying its own base when it adopts cultural studies uncritically. The different stance between theatre and cultural theories also occurs from the opposition of humanism vs. antihumanism. We have to introduce cultural theories selectively and properly not to destroy the inherent experience and domain of theatre.