• Nuclear Engineering and Technology
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• 제44권4호
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• pp.379-386
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• 2012

A symptom-based procedure with a critical safety function monitoring system has been established to reduce the operator's diagnosis and cognitive burden since the Three-Mile Island (TMI) accident. However, it has been reported that a symptom-based procedure also requires an operator's cognitive efforts to cope with off-normal events. This can be caused by mismatches between a static model, an emergency operating procedure (EOP), and a dynamic process, the nature of an ongoing situation. The purpose of this study is to share the evidence of mismatches that may result in an excessive cognitive burden in conducting EOPs. For this purpose, we analyzed simulated emergency operation records and observed some operator behaviors during the EOP operation: continuous steps, improper description, parameter check at a fixed time, decision by information previously obtained, execution complexity, operation by the operator's knowledge, notes and cautions, and a foldout page. Since observations in this study are comparable to the results of an existing study, it is expected that the operational behaviors observed in this study are generic features of operators who have to cope with a dynamic situation using a static procedure.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권5호
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• pp.2067-2080
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• 2016

Cooperative spectrum sensing (CSS) for vacant licensed bands is one of the key techniques in cognitive radio networks. Currently, sequential probability ratio test scheme (SPRT) is considered as a powerful soft decision approach to improve the sensing result for CSS. However, SPRT assumes all secondary users (SU) are honest, and thus offering opportunities for malicious SUs to launch the spectrum sensing data falsification attack (SSDF attack). To combat such misbehaved behaviors, recent efforts have been made to trust mechanism. In this paper, we argue that powering SPRT with traditional trust mechanism is not enough. Dynamic SSDF attackers can maintain high trust in an alternant process of submitting honest or false sensing data, resulting in difficultly detecting them. Noting that the trust value of dymamic SSDF attackers behave highly volatile, a novel trusted SPRT scheme (VSPRT) based on volatility decay analysis is proposed in this paper to mitigate the harmful effect of dynamic SSDF attackers in the process of the soft-decision data fusion, and thus improving the accuracy of the final sensing result. Simulation results show that the VSPRT scheme outperforms the conventional SPRT schemes.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권6호
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• pp.2838-2858
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• 2019

Traditional channel models for vehicle-to-vehicle (V2V) communication usually assume fixed velocity in static scattering environment. In the realistic scenarios, however, time-variant velocity for V2V results in non-stationary statistical properties of wireless channels. Dynamic scatterers with random velocities and directions have been always utilized to depict the non-stationary statistical properties of the channel. In this paper, a non-stationary geometry-based cooperative scattering channel model is proposed for multiple-input multiple-output (MIMO) V2V communication systems, where a birth-death process is used to capture the appearance and disappearance dynamic properties of moving scatterers that reflect the time-variant time correlation and Doppler spectrum characteristics. Moreover, our model has more straight and concise to study the impact of the vehicular traffic density on channel characteristics and thus avoid complicated procedure in deriving the analytical expressions of the channel parameters and functions. The numerical results validate our analysis and demonstrate that setting important parameters of our model can appropriately build up more purposeful measurement campaigns in the future.

• 한국실내디자인학회논문집
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• 제26권5호
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• pp.152-160
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• 2017

The purpose of this study is to propose a space design plan for brand experience that can enhance consumer satisfaction and brand awareness by conducting a survey on the consumer satisfaction with space expression methods in an eyewear flagship store. Through theoretical review, brand experience was defined as the 'process and outcome of experiences caused by stimulations associated with the brand in a series of processes. After reviewing previous studies, 5 elements of brand experience such as the sensory, emotional, behavioral, cognitive and relational experiences were extracted. Upon deriving a checklist through these elements, a survey was conducted. The analysis of the survey showed that the process composed of cognitive experiences that promoted to remember the brand was intensively expressed in spaces. Thus, the results of this study are as follows. First, the process composed of cognitive experience should be applied with a higher priority to increase brand awareness, and such a process accompanied by the behavioral and sensory experiences. Second, beyond a simple visual experience, various senses such as olfactory and auditory senses should be stimulated, and behavioral experience provided as an experience factor. Third, brand image and sales spaces should be composed under a single theme with a connectivity. Fourth, in external spaces, the curiosity of consumers should be stimulated with a theme matching the brand image. Fifth, it was found that the visitor satisfaction was higher when formative elements consisted of not only static but also dynamic features. Sixth, among the elements of brand experience, emotional experience should be improved to complete the 'process and outcome of experiences'. It is considered that further studies are needed, which expand the cases of eyewear flagship stores not only in Korea but also overseas, and propose more specific plans and design strategies through in-depth interview methods in the future.

• 정보관리학회지
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• 제32권1호
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• pp.7-22
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• 2015

이 논문은 시스템 성능을 최적화하기 위해 정적 및 동적 튜닝 방법을 이용한 웹 융합검색 연구의 내용을 보고합니다. 기존의 융합 방식을 넘어선 "다이나믹 튜닝"이라는 과정을 도입하여 웹의 다양한 정보소스의 기여를 최적화 시킬 수 있는 융합 공식을 생성하는 방법을 조사한 이 연구의 결과는 웹 검색 환경의 풍요로운 여러 데이터 소스를 활용하는 것이 효과적인 전략이라는 것을 보여주었습니다. 본 연구에서는 즉각적인 시스템 피드백 인지분석을 기반으로 융합 매개 변수를 미세 조정하는 반복적 인 다이나믹 튜닝 과정을 통해 크게 검색 성능을 향상시킬 수 있었습니다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권11호
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• pp.3751-3774
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• 2014

With the rapid development of wireless communication, the confliction between the scarce frequency resources and the low spectral efficiency caused by the stationary spectrum sharing strategies seriously restricts the evolution of the future mobile communication. For this purpose, cognitive radio (CR) emerges as one of the most promising inventions which can overcome the spectrum shortage. As the key technology and main objective of CR, spectrum sharing can make full use of the limited spectrum, alleviate the scarcity of frequency resources and improve the system utilities, playing thereby an important role in improving the system performance of cognitive radio networks (CRNs). In this survey, the spectrum sharing in CRNs is discussed in terms of the sharing process, mainstream sharing technologies and spectrum sharing models. In particular, comparisons of different spectrum sharing strategies are concluded, as well as that of different spectrum sensing schemes in sharing procedure. Moreover, some application examples of the spectrum sharing in CRNs, such as smart grid, public safety, cellular network and medical body area networks are also introduced. In addition, our previous related works are presented and the open research issues in the field of spectrum sharing are stated as well.

• 한국수학교육학회지시리즈A:수학교육
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• 제46권3호
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• pp.331-349
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• 2007

This study aims to improve the teaching and learning method on the conic sections. To do that the researcher analyzed the impact of dynamic geometry software on students' problem solving of the conic sections. Students often say, "I have solved this kind of problem and remember hearing the problem solving process of it before." But they often are not able to resolve the question. Previous studies suggest that one of the reasons can be students' tendency to approach the conic sections only using algebra or analytic geometry without the geometric principle. So the researcher conducted instructions based on the geometric and historico-genetic principle on the conic sections using dynamic geometry software. The instructions were intended to find out if the experimental, intuitional, mathematic problem solving is necessary for the deductive process of solving geometric problems. To achieve the purpose of this study, the researcher video taped the instruction process and converted it to digital using the computer. What students' had said and discussed with the teacher during the classes was checked and their behavior was analyzed. That analysis was based on Branford's perspective, which included three different stage of proof; experimental, intuitive, and mathematical. The researcher got the following conclusions from this study. Firstly, students preferred their own manipulation or reconstruction to deductive mathematical explanation or proving of the problem. And they showed tendency to consider it as the mathematical truth when the problem is dealt with by their own manipulation. Secondly, the manipulation environment of dynamic geometry software help students correct their mathematical misconception, which result from their cognitive obstacles, and get correct ones. Thirdly, by using dynamic geometry software the teacher could help reduce the 'zone of proximal development' of Vigotsky.

• 한국수학교육학회지시리즈A:수학교육
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• 제50권1호
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• pp.13-25
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• 2011

The Goals of mathematics education for the lower grades of primary school is to shape the basic concepts and the skills of mathematics. To achieve this goal, it is necessary an assessment which is able to help the students' learning activities by precisely diagnosing their basic mathematical capability. It should lend the students an assistance in diagnosing and revising their problems throughout teacher's cognitive participation in the process of mathematical problem solving. I would like to suggest the dynamic assessment as one of these kinds of approaches. In order to prove the utilities of this way, it was examined the necessity of dynamic assessment on the basis of the Vygotsky's theory after looking into the characteristics of the contents and methods of the mathematics education for the lower grades of primary school. Next, I researched the principles of the dynamic assessment and embodied the assessment tool to evaluate the mathematical achievement of the lower grades of the primary school. Lastly, it was provided the examples of the dynamic assessment tool in order to assist the practice of it.

• 인지과학
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• 제4권2호
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• pp.263-278
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• 1994

본 논문에서는 영어의 은유적효현을 분석하여 한국어로 번역하는 과정을 제안한다.기존의 영어 분석기나 번역기들은 주어진 범위나 상황내에서의 분석,번역을 시도하였고,은우적 표현에 대한 시도는 기피해 왔다. 제안된 과정은 복합어나 숙어를 처리하는 과정과는 다르게 다루어진다.(Lee(1985)[5],Yoon & Kim(1993)[8]참조). 숙어나 복합어는 그 구(phrase)전체를 하나의 단위(unit)로 처리하는 반면에,은유적표현의 처리과정은 주어진 술어나 논항의 기존범의를 확장(extension of smantic property)시켜 '은유사전'(metaphor dictionary)에서 별개로 처리된다.은유적 표현으로 사용된 어휘는 은유사전에'M'로 표시된다.

• 한국통신학회논문지
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• 제37권7A호
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• pp.560-568
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• 2012

인지 라디오가 무선통신을 효과적으로 수행하기 위해서, 가장 좋은 주파수 대역을 얻기 위해 수행해야 할 중요한 기능은 스펙트럼을 검출하고 결정하는 것이다. 이러한 것들은 서로 다른 요구조건을 갖는 사용자들이나 서로 다른 특성들을 갖는 채널들이 존재하는 이종 네트워크에서 더욱 나빠진다. 본 연구의 주요한 목적은 이종 인지 무선 네트워크에서 새로운 스펙트럼 결정 알고리즘을 설계하고 분석한다. 이것을 위해, 우선 인지 사용자들을 그들이 요구하는 서비스 품질(QoS)에 따라 서로 다른 트래픽 클래스들로 분류한다. 중앙 집중형 제어 형태로 동작하는 그룹단위의 협력 스펙트럼 검출은 하나의 트래픽 클래스내의 사용자들에 의해서 검출과정이 수행되며, 이 센싱 결과들은 나머지 트래픽 사용자들과 공유하는 형태이다. 다음은 사용자 요구조건들과 검출된 스펙트럼 채널 특성들에 따라 최적의 사용 가능한 대역을 선택하기 위해 계층 분석법(AHP)을 사용한다. 또한 스펙트럼 결정 알고리즘으로 효용함수를 사용한다. 시뮬레이션 분석 결과로서, 제안된 시스템은 가장 좋은 이용 가능한 스펙트럼 채널들을 효율적으로 선택할 수 있음을 보여주며, 시스템 구성의 복잡성을 감소시켜 줄 수 있음을 보여준다.