• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권4호
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• pp.1817-1836
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• 2020

Network convergence is considered as one of the key solutions to the problem of achieving future high-capacity and reliable communications. This approach overcomes the limitations of separate wireless technologies. Efficient interface selection is one of the most important issues in convergence networks. This paper solves the problem faced by users of selecting the most appropriate interface in the heterogeneous radio-access network (RAN) environment. Our proposed scheme combines a hierarchical evaluation of networks and game theory to solve the network-selection problem. Instead, of considering a fixed weight system while ranking the networks, the proposed scheme considers the service requirements, as well as static and dynamic network attributes. The best network is selected for a particular service request. To establish a hierarchy among the network-evaluation criteria for service requests, an analytical hierarchy process (AHP) is used. To determine the optimum network selection, the network hierarchy is combined with game theory. AHP attains the network hierarchy. The weights of different access networks for a service are calculated. It is performed by combining AHP scores considering user's experienced static network attributes and dynamic radio parameters. This paper provides a strategic game. In this game, the network scores of service requests for various RANs and the user's willingness to pay for these services are used to model a network-versus-user game. The Nash equilibria signify those access networks that are chosen by individual user and result maximum payoff. The examples for the interface selection illustrate the effectiveness of the proposed scheme.

• 정보처리학회논문지C
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• 제18C권2호
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• pp.111-118
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• 2011

최근 스마트폰의 인기로 인해 무선 멀티인터페이스를 이용한 네트워킹 서비스에 관심이 증가하고 있다. 이로 인해 무선 멀티인터페이스 지원을 위한 네트워킹 기술 연구가 활발히 진행 중이다. 이와 관련된 연구로써 IETF NetExt WG 에서 Proxy Mobile IPv6 (PMIPv6) 기반 멀티인터페이스 지원 기술에 대한 표준 기술이 논의 중에 있다. 기존 PMIPv6 프로토콜은 멀티 인터페이스 이동 노드가 PMIPv6 도메인에서 접속시 멀티인터페이스를 이용하여 동시 접속 및 인터페이스 사이에서의 핸드오버 지원을 위한 기본 기능을 제공하고 있다. 하지만 기존 프로토콜이 가진 기능은 동시 접속 후 이동 노드가 Inter-Technology Handover을 수행한 후 동시 접속 상황이 불가능하게 되는 문제점을 가지고 있다. 따라서 기존 프로토콜을 통한 플로우 기반의 멀티 호밍 서비스가 제공되지 못한다. 본 논문에서는 멀티인터페이스 이동 노드가 PMIPv6 도메인에 접속하는 시나리오에서 언급한 문제점을 정의하고 이를 해결하기 위한 방안으로 Hybrid Home Network Prefix 할당 방법을 제안한다.

• 스마트미디어저널
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• 제6권4호
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• pp.79-87
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• 2017

본 논문은 기존 노년층과는 다른 특성을 보이는 액티브 시니어의 사용자 경험 문제를 도출해 내기 위한 연구로 먼저 선행 연구분석을 통하여 'Visible', 'Desired Outcome', 'Immediate Feedback', 'Intuitiveness', 'Perceived Ease of Use'의 다섯 가지 요소를 사용자 interaction의 초기단계를 이루는 요소로 추출하였고 이를 기반으로 Interface 사용 중에 사용자의 행위와 인지 내용을 분석하였다. 이를 통해 사용과정에서 생기는 문제점을 도출하였으며, 다섯 가지 요소와 사용자의 주관 평가 간의 상관관계를 분석하였다. 사용자 경험의 주관 평가에는 PSSUQ를 사용하였으며 SPSS 22 버전을 사용하여 pearson 상관 분석을 실시하였다. 본 논문의 연구결과는 다음과 같다. 첫째, App 사용 시 액티브 시니어 사용자들이 겪는 가장 큰 문제는 desired outcome차원의 문제로 볼 수 있다. 둘째, interface assessment 다섯 가지 요소 중 'Desired Outcome', 'Perceived Ease of Use' 두 가지 요소만이 PSSUQ 설문 결과와 통계적으로 유의미한 상관관계를 보이는 것으로 나타났으며 나머지 'Visible', 'Immediate Feedback', 'Intuitiveness'의 세 요소는 사용자의 주관 평가와 상관관계를 보이지 않았다. 본 논문의 연구결과에 의하면 액티브 시니어는 기존의 노년층과는 다른 특징을 가지고 있어 'Desired Outcome'과 'Perceived ease of use'차원의 문제가 더 많은 영향을 미치는 요소로 볼 수 있으며 기존의 연구에서 중요한 요소로 거론한 'Visible', 'Immediate feedback', 'Intuitiveness'는 명확한 상관관계가 없는 것으로 볼 수 있다. 이는 기존 노년층과 달리 액티브 시니어의 경우 PC나 스마트폰 사용 경험의 누적으로 인하여 visible, immediate feedback, intuitiveness 등의 요소에 어려움을 적게 겪기 때문인 것으로 보인다. 본 논문의 연구 결과는 다양한 수요를 보이고 있는 액티브 시니어용 App의 개발에 의미 있게 활용될 것이다.

• Journal of Mechanical Science and Technology
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• 제19권10호
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• pp.1864-1874
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• 2005

This paper describes a wearable multi-modal user interface design and its implementation for a teleoperated field robot system. Recently some teleoperated field robots are employed for hazard environment applications (e.g. rescue, explosive ordnance disposal, security). To complete these missions in outdoor environment, the robot system must have appropriate functions, accuracy and reliability. However, the more functions it has, the more difficulties occur in operation of the functions. To cope up with this problem, an effective user interface should be developed. Furthermore, the user interface is needed to be wearable for portability and prompt action. This research starts at the question: how to teleoperate the complicated slave robot easily. The main challenge is to make a simple and intuitive user interface with a wearable shape and size. This research provides multi-modalities such as visual, auditory and haptic sense. It enables an operator to control every functions of a field robot more intuitively. As a result, an EOD (explosive ordnance disposal) demonstration is conducted to verify the validity of the proposed wearable multi-modal user interface.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권9호
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• pp.3169-3185
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• 2021

The majority of students in higher education institutions are among generation Z. They have always depended on e-learning to support their learning activities. Therefore, higher education institutions should provide an attractive e-learning platform. E-learning interface design should be reviewed frequently to smoothen the interaction between students and the e-learning system. It is because interface design that fulfils generation Z students' preferences and expectations may upsurge their participation in e-learning. However, interface design has continually been condemned and turn out to be part of the problem that contributes to the failure of e-learning. Lack of consideration about generation Z students' preferences towards the interface design of e-learning is the factor that leads to these causes. Therefore, this study focused on identifying design characteristics of colour and graphic elements of e-learning from generation Z students' perception. This research involved a purposive sampling method for questionnaire among students of generation Z. The findings from this study could help e-learning developers to design the interface of e-learning that is suitable for generation Z students that will consider color and graphic as important characteristics.

• 한국전산구조공학회논문집
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• 제30권6호
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• pp.515-522
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• 2017

본 논문에서는 2개 이상의 기하형상이 순응 또는 비순응 경계면에서 접합된 멀티패치 문제에 대한 아이소-지오메트릭 해석에 대해서 연구하였다. 패치 경계면에서 응력의 연속성을 표현하는 방법으로 Nitsche 방법론과 마스터-슬레이브 방법에 기반한 방법론에 대해서 지배방정식을 유도하고 아이소-지오메트릭 이산화를 수행하였다. 멀티패치 문제에 대해서 두 방법론의 차이점을 간단하게 비교하였으며, 후처리 과정에서 사용되는 NURBS 곡면 기반의 응력 복원법에 대해서 기술하였다. 수치예제에서 비순응 경계면을 가지는 멀티패치 빔 문제를 통해 Nitshce 방법론을 검증하였으며, 응력집중을 가지는 문제에서 소개된 두 방법론이 유사한 결과를 보이는 것을 확인하였다. 소개된 NURBS 곡면 기반의 응력 복원법을 후처리에서 도입할 경우 멀티패치 문제의 경계면에서 개선된 연속적인 응력을 보임을 알 수 있다.

• Nuclear Engineering and Technology
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• 제50권3호
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• pp.327-339
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• 2018

This article presents a new global-local hybrid coarse-mesh finite difference (HCMFD) method for efficient parallel calculation of pin-by-pin heterogeneous core analysis. In the HCMFD method, the one-node coarse-mesh finite difference (CMFD) scheme is combined with a nodal expansion method (NEM)-based two-node CMFD method in a nonlinear way. In the global-local HCMFD algorithm, the global problem is a coarse-mesh eigenvalue problem, whereas the local problems are fixed source problems with boundary conditions of incoming partial current, and they can be solved in parallel. The global problem is formulated by one-node CMFD, in which two correction factors on an interface are introduced to preserve both the surface-average flux and the net current. Meanwhile, for accurate and efficient pin-wise core analysis, the local problem is solved by the conventional NEM-based two-node CMFD method. We investigated the numerical characteristics of the HCMFD method for a few benchmark problems and compared them with the conventional two-node NEM-based CMFD algorithm. In this study, the HCMFD algorithm was also parallelized with the OpenMP parallel interface, and its numerical performances were evaluated for several benchmarks.

• 산업공학
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• 제13권3호
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• pp.479-485
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• 2000

We consider a Location-Allocation Problem with the Cost of Land(LAPCL). LAPCL has extremely huge size of problem and complex characteristic of location and allocation problem. Heuristics and decomposition approaches on simple Location-Allocation Problem were well developed in last three decades. Recently, genetic algorithm(GA) is used widely at combinatorics and NLP fields. A lot of research shows that GA has efficiency for finding good solution. Our main motive of this research is developing of a package for LAPCL. We found that LAPCL could be reduced to trivial problem, if locations were given. In this case, we can calculate fitness function by simple technique. We built a database constructed by zipcode, latitude, longitude, administrative address and posted land price. This database enables any real field problem to be coded into a mathematical location problem. We developed a package for a class of multi-location problem at PC. The package allows for an interactive interface between user and computer so that user can generate various solutions easily.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.603-608
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• 2003

Recently, personal robots and home robots are developing by many companies and research groups. It is considered that a general effective interface for user of those robots is speech or voice. In this paper, Japanese speech based man-machine interface system is discussed for reflecting the fuzziness of natural language on robots, by using fuzzy reasoning. The present system consists of the derivation part of action command and the modification part of the derived command. In particular, a unique problem of Japanese is solved by applying the morphological analyzer ChaSen. The proposed system is applied for the motion control of a robot manipulator. It is proved from the experimental results that the proposed system can easily modify the same voice command to the actual different levels of the command, according to the current state of the robot.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2001년도 추계학술대회(한국공작기계학회)
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• pp.269-274
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• 2001

Applications of Brazing in the studying fields such as High-Speed Machining are very increasing in various industry fields. Therefore, Applying to the fracture mechanics by numerical analysis method is very important to analyse the crack problem Dissimilar Materials in Brazed Interface. In this study, Stress intensity Factor (S.I.F) is analysed to investigate crack behavior on the crack tip of dissimilar materials in brazed interface such as a Hardmetal and a HSS by two dimensional(2-D) Boundary Element Method (BEM). Kelvin's solution was used as a fundamental solution in BEM analysis and stress extrapolation method was used to determine Stress Intensity Factor.