• Journal of the korean society of oceanography
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• 제38권2호
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• pp.52-59
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• 2003

In this paper, a brief overview on data assimilation is provided in the context of oceanographic application. The ocean data assimilation needs to ingest various types of data such as satellites and floats, thus essentially requires dynamically-consistent assimilation methods. For such purpose, sequential and variational approaches are discussed and compared. The major advantage of the Kalman filter (KF) is that it can forecast error covariances at each time step. However, for models with very large dimension of state vector, the KF Is exceedingly expensive and computationally less efficient than four-dimensional variational assimilation (4D-Var). For operational application, simplified 4D-Var schemes as well as ensemble KF may be considered.

• 정보과학회 컴퓨팅의 실제 논문지
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• 제23권12호
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• pp.698-702
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• 2017

자연 언어 처리(Natural Language Processing) 분야에 심층 신경망(Deep Neural Network)이 소개된 이후, 단어, 문장 등의 의미를 나타내기 위한 분산 표상인 임베딩(Embedding)을 학습하기 위한 연구가 활발히 진행되고 있다. 임베딩 학습을 위한 방법으로는 크게 문맥 기반의 텍스트 모델링 방법과, 기학습된 임베딩을 결합하여 더 긴 텍스트의 분산 표상을 계산하고자 하는 결합 기반의 텍스트 모델링 방법이 있다. 하지만, 기존 결합 기반의 텍스트 모델링 방법은 최적 결합 단위에 대한 고찰 없이 단어를 이용하여 연구되어 왔다. 본 연구에서는 비교 실험을 통해 문서 임베딩 생성에 적합한 결합 기법과 최적 결합 단위에 대해 알아본다. 또한, 새로운 결합 방법인 담화 분석 기반의 결합 방식을 제안하고 실험을 통해 기존의 순차적 결합 기반 신경망 모델 대비 우수성을 보인다.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.877-885
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• 2022

Vision-based activity recognition has been widely attempted at construction sites to estimate productivity and enhance workers' health and safety. Previous studies have focused on extracting an individual worker's postural information from sequential image frames for activity recognition. However, various trades of workers perform different tasks with similar postural patterns, which degrades the performance of activity recognition based on postural information. To this end, this research exploited a concept of human-object interaction, the interaction between a worker and their surrounding objects, considering the fact that trade workers interact with a specific object (e.g., working tools or construction materials) relevant to their trades. This research developed an approach to understand the context from sequential image frames based on four features: posture, object, spatial features, and temporal feature. Both posture and object features were used to analyze the interaction between the worker and the target object, and the other two features were used to detect movements from the entire region of image frames in both temporal and spatial domains. The developed approach used convolutional neural networks (CNN) for feature extractors and activity classifiers and long short-term memory (LSTM) was also used as an activity classifier. The developed approach provided an average accuracy of 85.96% for classifying 12 target construction tasks performed by two trades of workers, which was higher than two benchmark models. This experimental result indicated that integrating a concept of the human-object interaction offers great benefits in activity recognition when various trade workers coexist in a scene.

• Human Ecology Research
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• 제55권1호
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• pp.67-80
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• 2017

This study develops an the ideal portrait of a human being pursuing in home economics education from a critical science perspective. The practical problem is 'what should the ideal portrait of a human being pursuing in home economics education with a critical science perspective be?' was addressed through a practical reasoning research method with the stages of valued ends, context, alternatives, consequence, and a final plan. The sequential flow of understanding values and contexts established the setting of three valued ends by organizing issues and categorized areas of individuals, families, society, and cultural from a critical science perspective. The ideal portrait of human being was specifically stated, in the self-formation, independent, inter-subjectivity, social participation, and enculturation according to subcategories; in addition, the stated ideal portrait of human being was modified through expert consultations. Alternatives and consequences were reexamined for the validity of the statement and restated as a comprehensive statement of ideal portrait of a human being that included a restatement of the five areas. An ideal portrait of a human being pursuing in home economics education from a critical science perspective was made from alternative ideal portraits of the proposed human being and stated as 'a person who can continually act autonomously in one's life-world.'

• Journal of Mechanical Science and Technology
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• 제15권7호
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• pp.876-888
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• 2001

For a large scaled optimization based on response surface methods, an efficient quadratic approximation method is presented in the context of the trust region model management strategy. If the number of design variables is η, the proposed method requires only 2η+1 design points for one approximation, which are a center point and tow additional axial points within a systematically adjusted trust region. These design points are used to uniquely determine the main effect terms such as the linear and quadratic regression coefficients. A quasi-Newton formula then uses these linear and quadratic coefficients to progressively update the two-factor interaction effect terms as the sequential approximate optimization progresses. In order to show the numerical performance of the proposed method, a typical unconstrained optimization problem and two dynamic response optimization problems with multiple objective are solved. Finally, their optimization results compared with those of the central composite designs (CCD) or the over-determined D-optimality criterion show that the proposed method gives more efficient results than others.

• Structural Engineering and Mechanics
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• 제43권5호
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• pp.679-690
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• 2012

A new concept sea-floating port called mobile harbor has been introduced, in order to resolve the limitation of current above-ground port facilities against the continuous growth of worldwide marine transportation. One of important subjects in the design of a mobile harbor is to secure the dynamic stability against wave-induced excitation, because a relatively large-scale heavy crane system installed at the top of mobile harbor should load/unload containers at sea under the sea state up to level 3. In this context, this paper addresses a two-step sequential analytical-numerical method for analyzing the structural dynamic response of the mobile harbor crane system to the wave-induced rolling excitation. The rigid ship motion of mobile harbor by wave is analytically solved, and the flexible dynamic response of the crane system by the rigid ship motion is analyzed by the finite element method. The hydrodynamic effect between sea water and mobile harbor is reflected by means of the added moment of inertia.

• STI Policy Review
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• 제1권1호
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• pp.93-109
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• 2010

Over the last decade, some Korean enterprises have emerged to become global players in their specialized products. How have they achieved such tremendous technological progress in a short period of time? This paper explores that question by examining the characteristics of technological innovation activities at major Korean enterprises. The paper begins with a brief review of the stages of economic growth and science and technology development in Korea. Then, the existing literature, explaining the Korean innovation model, is analyzed in order to establish a new framework for the Korean innovation model. Specifically, Korean firms have experienced three sequential phases, and thus, the Korean model, at the firm level, can be coined as "path-following," "path-revealing," and "path-creating." Then, the stylized facts in the first phase (path-following) and the second phase (path-revealing) are discussed, in the context of empirical evidence from the areas of memory chips, automobiles, shipbuilding, and steel. In terms of technology development, the Korean model has evolved as "collective learning" in the first phase, "collective recombination" of existing knowledge and technology in the second phase, and is assumed as "collective creativity" in the third phase. Ultimately, all three can be classified as "collective creation". Korean firms now face a transition in the modes of technological innovation in order to efficiently implement the third phase. To achieve remarkable progress again, as they did in the past, and to sustain the growth momentum, Korean firms should challenge new dimensions such as creative technological ideas, distinctive technological capabilities, and unique innovation systems -- all of which connote 'uniqueness'. Finally, some lessons from the Korean technological innovation experience are addressed.

• 한국정보과학회논문지:데이타베이스
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• 제29권5호
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• pp.404-415
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• 2002

본 논문에서는, 무선 데이타 방송 환경에서 여러 데이타 항목을 지정된 순서에 의해 접근해야 하는 읽기-전용 트랜잭션의 일관성 유지와 관련된 주제를 다룬다. 데이타 방송 환경에서 사용자는 항상 순차적으로 데이타에 접근하게 된다. 이러한 속성을 가진 환경에서, 본 논문은 기선언-기반 질의 최적화 방식을 제안하며, 이를 이용하여 지역 캐쉬와 관련된 두 가지 트랜잭션 실행 기법을 개발하였다. 또한 제안된 기법들을 수학적으로 분석함으로써 성능을 평가하였다. 평가 결과에 의해, 본 논문에서 제안한 기선언 방식이 응답 시간을 상당히 단축시켰으며, 작업량이 동적으로 변하더라도 훨씬 더 잘 적응될 수 있음을 알 수 있다.

• 대한안전경영과학회지
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• 제25권2호
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• pp.175-185
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• 2023

Prior studies focusing on safety behavior have not given sufficient consideration to the potential impact exerted by different leadership styles. Of these various styles, my attention is specifically drawn to the influence of ethical leadership on safety behavior. In this paper, I delve into the influence of ethical leadership on safety behavior, shedding light on both the underlying mechanisms(mediators) and a significant contextual factor(moderator). I probe into the successive mediating roles of employees' trust in the organization and their commitment to it, within the context of the relationship between ethical leadership and safety behavior. Further, I posit that authentic leadership positively adjusts the connection between ethical leadership and organizational trust. My findings underscore that ethical leadership enhances employee safety behavior, facilitated by the chain mediation of trust in the organization and organizational commitment. Moreover, I discover that authentic leadership, as a positive moderator, magnifies the favorable impact of ethical leadership on organizational trust. This paper will also articulate the theoretical implications, practical applications, and limitations of the study.

• Smart Structures and Systems
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• 제33권3호
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• pp.177-188
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• 2024

The fatigue-induced sequential failure of a structure having structural redundancy requires system-level analysis to account for stress redistribution. System reliability-based design optimization (SRBDO) for preventing fatigue-initiated structural failure is numerically costly owing to the inclusion of probabilistic constraints. This study incorporates the Branch-and-Bound method employing system reliability Bounds (termed the B³ method), a failure-path structural system reliability analysis approach, with a metaheuristic optimization algorithm, namely grey wolf optimization (GWO), to obtain the optimal design of structures under fatigue-induced system failure. To further improve the efficiency of this new optimization framework, an additional bounding rule is proposed in the context of SRBDO against fatigue using the B³ method. To demonstrate the proposed method, it is applied to complex problems, a multilayer Daniels system and a three-dimensional tripod jacket structure. The system failure probability of the optimal design is confirmed to be below the target threshold and verified using Monte Carlo simulation. At earlier stages of the optimization, a smaller number of limit-state function evaluation is required, which increases the efficiency. In addition, the proposed method can allocate limited materials throughout the structure optimally so that the optimally-designed structure has a relatively large number of failure paths with similar failure probability.