• 한국문헌정보학회지
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• 제43권4호
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• pp.241-264
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• 2009

본 연구는 전자저널의 효율적인 검색과 이용을 위한 방안을 모색하기 위해 문헌조사와 96명을 대상으로 한 설문조사 및 두 개의 전자자원관리시스템(Verde와 Millennium)에 대한 사례조사를 수행하고, 이를 바탕으로 하여 전자저널 검색 모형을 설계한 후 평가하였다. 이 모형의 핵심은 택소노미 기반의 전자자원관리시스템에 폭소노미 태그 기능을 결합하여 시스템 중심의 서비스와 이용자 중심의 서비스를 상호 보완하였다는 점이다. 또한 이용자가 직접 부여하는 태그 이외에 시스템내의 로그파일을 이용하여 자동으로 태그를 생성하여 전자저널 검색의 접근점을 확장시키고, 태그의 비통제 어휘 문제를 극복하기 위해서 관리자가 시스템을 통해서 태그를 통제할 수 있는 기능도 포함시켰다.

• Nuclear Engineering and Technology
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• 제53권10호
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• pp.3275-3285
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• 2021

A Nuclear Power Plant (NPP) is a complex dynamic system-of-systems with highly nonlinear behaviors. In order to control the plant operation under both normal and abnormal conditions, the different systems in NPPs (e.g., the reactor core components, primary and secondary coolant systems) are usually monitored continuously, resulting in very large amounts of data. This situation makes it possible to integrate relevant qualitative and quantitative knowledge with artificial intelligence techniques to provide faster and more accurate behavior predictions, leading to more rapid decisions, based on actual NPP operation data. Data-driven models (DDM) rely on artificial intelligence to learn autonomously based on patterns in data, and they represent alternatives to physics-based models that typically require significant computational resources and might not fully represent the actual operation conditions of an NPP. In this study, a feed-forward backpropagation artificial neural network (ANN) model was trained to simulate the interaction between the reactor core and the primary and secondary coolant systems in a pressurized water reactor. The transients used for model training included perturbations in reactivity, steam valve coefficient, reactor core inlet temperature, and steam generator inlet temperature. Uncertainties of the plant physical parameters and operating conditions were also incorporated in these transients. Eight training functions were adopted during the training stage to develop the most efficient network. The developed ANN model predictions were subsequently tested successfully considering different new transients. Overall, through prompt prediction of NPP behavior under different transients, the study aims at demonstrating the potential of artificial intelligence to empower rapid emergency response planning and risk mitigation strategies.

• 전자공학회논문지
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• 제51권12호
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• pp.123-129
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• 2014

복합 기능 기기의 발전에 따라 카메라는 방범 시스템, 운전자 보조 시스템 등 여러 분야에서 광범위하게 사용되고 있으며 많은 사람들은 이러한 시스템에 노출되어 있다. 따라서 시스템은 인간의 행동을 인식할 수 있고 인식된 행동으로부터 얻은 정보를 이용하여 유용한 기능을 사용자에게 제공할 수 있어야 한다. 본 논문은 이차원 영상 이미지에서 인식된 기계적 학습 접근 방법을 사용한 인간 행동 패턴 인식 기법을 제안한다. 제안된 방법은 인식된 사용자의 행동 패턴을 기반으로 사용자에게 유용한 기능을 실행하기 위한 정보를 제공하게 될 것이다. 먼저 소개하는 방법은 전화 통화 행동 인식이다. 차량 내부에 운전자 방향으로 설치된 블랙박스가 전화 통화 행동을 인식한다면 안전 운전을 위해서 운전자에게 경고를 줄 수 있다. 두 번째 제안하는 방법은 안전 운행을 위한 전방 주시 행동 인식으로서 운전자가 전방 주시하고 있는지 아닌지를 판단하기 위한 방법과 기준을 제안한다. 본 논문은 실시간 영상 조건에서 제안하는 인식 방법의 효용성을 실험 결과를 통해서 보여준다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권5호
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• pp.1963-1978
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• 2015

With the advancement of mobile web environments, identification and analysis of the user behavior play a significant role and remains a challenging task to implement with variations observed in the model. This paper presents an efficient method for mining optimized user behavior prediction model using genetic algorithm on mobile web structure. The framework of optimized user behavior prediction model integrates the temporary and permanent register information and is stored immediately in the form of integrated logs which have higher precision and minimize the time for determining user behavior. Then by applying the temporal characteristics, suitable time interval table is obtained by segmenting the logs. The suitable time interval table that split the huge data logs is obtained using genetic algorithm. Existing cluster based temporal mobile sequential arrangement provide efficiency without bringing down the accuracy but compromise precision during the prediction of user behavior. To efficiently discover the mobile users' behavior, prediction model is associated with region and requested services, a method called optimized user behavior Prediction Model using Genetic Algorithm (PM-GA) on mobile web structure is introduced. This paper also provides a technique called MAA during the increase in the number of models related to the region and requested services are observed. Based on our analysis, we content that PM-GA provides improved performance in terms of precision, number of mobile models generated, execution time and increasing the prediction accuracy. Experiments are conducted with different parameter on real dataset in mobile web environment. Analytical and empirical result offers an efficient and effective mining and prediction of user behavior prediction model on mobile web structure.

• 융합보안논문지
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• 제18권5_1호
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• pp.45-51
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• 2018

데이터의 활용도와 중요성이 점차 높아짐에 따라 데이터와 관련된 사고와 피해는 점점 증가 하고 있으며, 특히 내부자에 의한 사고는 그 위험성이 더 높다. 이런 내부자의 공격은 전통적인 보안 시스템으로 방어하기 힘들어, 규칙 기반의 이상 행동 탐지 방법이 널리 활용되어오고 있다. 하지만, 새로운 공격 방식 및 새로운 환경과 같이 변화에 유연하게 적응하지 못하는 문제점을 가지고 있다. 본 논문에서는 이에 대한 해결책으로서 통계적 마르코프 모델 기반의 적응형 이상 이동 탐지 프레임워크를 제안하고자 한다. 이 프레임워크는 사람의 이동에 초점을 맞추어 내부자에 의한 위험을 사전에 탐지한다. 이동에 직접적으로 영향을 주는 환경 요소와 지속적인 통계 학습을 통해 변화하는 환경에 적응함으로써 오탐지와 미탐지를 최소화하도록 설계되었다. 프레임워크를 활용한 실험에서는 0.92의 높은 F2-점수를 얻을 수 있었으며, 나아가 정상으로 보여지지만, 의심해볼 이동까지 발견할 수 있었다. 통계 학습과 환경 요소를 바탕으로 행동과 관련된 데이터와 모델링 알고리즘을 다양화 시켜 적용한다면 보다 더 범위 넓은 비정상 행위에 대해 탐지할 수 있는 확장성을 제공한다.

• Smart Structures and Systems
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• 제31권3호
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• pp.247-257
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• 2023

In structural health monitoring of large-scale structures, optimal sensor placement plays an important role because of the high cost of sensors and their supporting instruments, as well as the burden of data transmission and storage. In this study, a vibration sensor placement algorithm based on deep reinforcement learning (DRL) is proposed, which can effectively solve non-convex, high-dimensional, and discrete combinatorial sensor placement optimization problems. An objective function is constructed to estimate the quality of a specific vibration sensor placement scheme according to the modal assurance criterion (MAC). Using this objective function, a DRL-based algorithm is presented to determine the optimal vibration sensor placement scheme. Subsequently, we transform the sensor optimal placement process into a Markov decision process and employ a DRL-based optimization algorithm to maximize the objective function for optimal sensor placement. To illustrate the applicability of the proposed method, two examples are presented: a 10-story braced frame and a sea-crossing bridge model. A comparison study is also performed with a genetic algorithm and particle swarm algorithm. The proposed DRL-based algorithm can effectively solve the discrete combinatorial optimization problem for vibration sensor placements and can produce superior performance compared with the other two existing methods.

• Asia pacific journal of information systems
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• 제18권4호
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• pp.105-130
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• 2008

Consumers of e-learning market differ from those of other markets in that they are replaced in a specific time scale. For example, e-learning contents aimed at highschool senior students cannot be consumed by a specific consumer over the designated period of time. Hence e-learning service providers need to attract new groups of students every year. Due to lack of information on products designed for continuously emerging consumers, the consumers face difficulties in making rational decisions in a short time period. Increased uncertainty of product purchase leads customers to herding behaviors to obtain information of the product from others and imitate them. Taking into consideration of these features of e-learning market, this study will focus on the online herding behavior in purchasing e-learning contents. There is no definite concept for e-learning. However, it is being discussed in a wide range of perspectives from educational engineering to management to e-business etc. Based upon the existing studies, we identify two main view-points regarding e-learning. The first defines e-learning as a concept that includes existing terminologies, such as CBT (Computer Based Training), WBT (Web Based Training), and IBT (Internet Based Training). In this view, e-learning utilizes IT in order to support professors and a part of or entire education systems. In the second perspective, e-learning is defined as the usage of Internet technology to deliver diverse intelligence and achievement enhancing solutions. In other words, only the educations that are done through the Internet and network can be classified as e-learning. We take the second definition of e-learning for our working definition. The main goal of this study is to investigate what factors affect consumer intention to purchase e-learning contents and to identify the differential impact of the factors between consumers with purchase experience and those without the experience. To accomplish the goal of this study, it focuses on herding behavior and perceived usefulness as antecedents to behavioral intention. The proposed research model in the study extends the Technology Acceptance Model by adding herding behavior and usability to take into account the unique characteristics of e-learning content market and e-learning systems use, respectively. The current study also includes consumer experience with e-learning content purchase because the previous experience is believed to affect purchasing intention when consumers buy experience goods or services. Previous studies on e-learning did not consider the characteristics of e-learning contents market and the differential impact of consumer experience on the relationship between the antecedents and behavioral intention, which is the target of this study. This study employs a survey method to empirically test the proposed research model. A survey questionnaire was developed and distributed to 629 informants. 528 responses were collected, which consist of potential customer group (n = 133) and experienced customer group (n = 395). The data were analyzed using PLS method, a structural equation modeling method. Overall, both herding behavior and perceived usefulness influence consumer intention to purchase e-learning contents. In detail, in the case of potential customer group, herding behavior has stronger effect on purchase intention than does perceived usefulness. However, in the case of shopping-experienced customer group, perceived usefulness has stronger effect than does herding behavior. In sum, the results of the analysis show that with regard to purchasing experience, perceived usefulness and herding behavior had differential effects upon the purchase of e-learning contents. As a follow-up analysis, the interaction effects of the number of purchase transaction and herding behavior/perceived usefulness on purchase intention were investigated. The results show that there are no interaction effects. This study contributes to the literature in a couple of ways. From a theoretical perspective, this study examined and showed evidence that the characteristics of e-learning market such as continuous renewal of consumers and thus high uncertainty and individual experiences are important factors to be considered when the purchase intention of e-learning content is studied. This study can be used as a basis for future studies on e-learning success. From a practical perspective, this study provides several important implications on what types of marketing strategies e-learning companies need to build. The bottom lines of these strategies include target group attraction, word-of-mouth management, enhancement of web site usability quality, etc. The limitations of this study are also discussed for future studies.

• 한국ITS학회 논문지
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• 제13권6호
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• pp.10-24
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• 2014

돌발상황에 대한 차내 경고 정보제공은 잠재적인 교통사고를 예방하고, 운전자의 적절한 회피행동을 유도하여 사고발생시 사고심각도를 감소시킬 수 있다. 그러나 부적절한 경고정보를 제공할 경우 운전자의 부적절한 판단을 유도하여 위험상황이 발생할 가능성을 높일 수 있다. 그러므로 운전자들이 경고정보를 가장 효과적으로 받아들일 수 있도록 정보 제공유무에 따라 실제 운전자의 반응특성을 분석하고 차내 경고정보 시스템을 다각도에서 평가할 수 있는 평가지표를 개발은 중요한 연구 주제이다. 본 연구에서는 다기준의사결정론을 적용하여 혼합가중치기반 운전자의 횡방향 및 종방향 주행안전성을 고려한 통합평가지표를 제시하였다. 가상주행실험을 통해 차내 경고정보 제공 전 후의 운전자 반응 특성 변수를 추출하여 운전자 반응특성 평가지표를 선정하였으며, 최적의 운전자 반응특성 평가지표를 선정하였다. 이때, 횡방향 및 종방향 주행안전성을 모두 고려하기 위하여 다기준의사결정방법론을 적용하여 종합적인 평가를 수행할 수 있도록 하였다. 본 연구에서 제시한 방법론은 다양한 유형의 경고정보제공시스템 도입시 운전자의 반응을 고려한 시스템 설계 및 도입에 따른 교통안전효과평가에 효과적으로 적용 가능할 것으로 판단된다.

• 한국멀티미디어학회논문지
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• 제18권3호
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• pp.387-400
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• 2015

A fuzzy logic based mobile robot navigation system was developed to improve the driving ability without trapping inside obstacles in complex terrains, which is one of the most concerns in robot navigation in unknown terrains. The navigation system utilizes the data from ultrasonic sensors to recognize the distances from obstacles and the position information from a GPS sensor. The fuzzy navigation system has two groups of behavior rules, and the robot chooses one of them based on the information from sensors while navigating for the targets. In plain terrains the robot with the proposed algorithm uses one rule group consisting of behavior rules for avoiding obstacle, target steering, and following edge of obstacle. Once trap is detected the robot uses the other rule group consisting of behavior rules strengthened for following edge of obstacle. The output signals from navigation system control the speed of two wheels of the robot through the fuzzy logic data process. The test was conducted in the Matlab based mobile robot simulator developed in this study, and the results show that escaping ability from obstacle is improved.

• 반도체디스플레이기술학회지
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• 제17권1호
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• pp.6-11
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• 2018

With the development of the Internet of Things technology, a system that ensures the self-adaptability of an environment that includes various IoT devices is attracting public attention. The rules for determining behavior rules in existing self-adaptation systems are based on the assumption of changes in system members and environment. However, in the IoT environment, flexibility is required to determine the behavior rules of various types of IoT devices that change in real time. In this paper, we propose a rule configuration in a self-adaptive system using SWRL based on OWL ontology. The self-adaptive system using the OWL - SWRL rule configuration has two advantages. The first is based on OWL ontology, so we can define the characteristics and behavior of various types of IoT devices as an integrated concept. The second is to define the concept of a rule as a specific language type, and to add, modify and delete a rule at any time as needed. Through the rule configuration in the adaptive system, we have shown that the rule defined in SWRL can provide flexibility and deeper concept expression function to adaptability to IoT environment.