• Advances in robotics research
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• 제2권3호
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• pp.237-245
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• 2018

This study evaluates the efficacy of a class robust control scheme namely active force control in performing a joint based trajectory tracking of an upper limb exoskeleton in rehabilitating the elbow joint. The plant of the exoskeleton system is obtained via system identification method whilst the PD gains were tuned heuristically. The estimated inertial parameter that enables the AFC disturbance rejection effect is attained by means of a non-nature based metaheuristic optimisation technique known as simulated Kalman filter (SKF). It was demonstrated from the present investigation that the proposed PDAFC scheme outperformed the classical PD algorithm in tracking the prescribed trajectory both in the presence and without the presence of disturbance attributed by the mannequin limb weights (1 kg and 1.5 kg) that mimics the weight of actual human limb weight. Therefore, it is apparent from the results obtained from the present study that the proposed control scheme, i.e., PDAFC is suitable for the application of exoskeleton for stroke rehabilitation.

• Journal of Communications and Networks
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• 제11권4호
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• pp.368-374
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• 2009

This paper focuses on a distributed multiple spectrum pricing scheme to maximize system capacity in next generation multiaccess systems, where multimode user equipments (MUEs) can connect simultaneously to multiple base stations (BSs) with multiple radio access technologies (RATs). The multi-price based scheme provides a distributed decision making for an optimal solution where radio resource allocations are determined by each MUE, unlike most centralized mechanisms where BS controls the whole radio resource. By the proposed optimal solution, MUEs can decide their share of spectrum bands and power allocation according to the spectrum price of each RAT, and at the same time the multiaccess system can achieve maximized total throughput. Numerical analysis shows that the proposed scheme achieves the maximal capacity by distributed resource allocation for the multiaccess system.

• International Journal of Computer Science & Network Security
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• 제22권3호
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• pp.9-16
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• 2022

The relevance of the topic is determined by the existence of inconsistencies between economic and environmental aspects of innovative development of urban logistics infrastructure, as well as the conflict of public, state and private commercial interests in this issue. The purpose of the article is to determine the principles and effective tools for innovative development of urban logistics infrastructure, taking into account pandemic constraints. The influence of the environmental aspect on the dynamics of transport flows was analyzed in detail and characterized, the scheme of determining the optimal solution for the development of the city was proposed considering the compromise between economic and ecological interests of society, state and business entities. A scheme of innovative development of urban logistics infrastructure under pandemic constraints was also developed. Materials of the article are relevant for developers of city plans, managers of urban logistics infrastructure, employees of enterprises participating in transport and logistics markets, scientists, and doctoral students.

• 한국통신학회논문지
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• 제42권5호
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• pp.1058-1068
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• 2017

V2X 통신에서, 사이드링크 수신 능력들이 없는 디바이스들 지원하기 위한 경우 및 단말의 파워 소비 감소가 요구되는 경우를 고려하여 랜덤 기반의 자원 선택 방식이 요구된다. 본 논문에서는 PSCCH 주기 내에서의 데이터를 위한 서브프레임 풀에 대하여 하나의 TRP를 반복 적용하는 D2D에서의 자원 선택 방식을 개선하여, 보다 향상된 랜덤 자원 선택 방식을 위해 단말-특정한 시드 값을 가지는 의사-랜덤 시퀀스를 바탕으로 TRP가 매 적용마다 달리 적용되는 방식을 제안하였다. 수치 분석을 통해 제안된 기술의 성능을 분석한 결과, 데이터 TB을 위해 각 단말에게 할당된 자원들 간의 충돌 확률이 줄어들며 이를 통해 자원 출동을 최대한 피하면서 동시에 자원할당이 가능한 단말의 개수를 늘릴 수 있는 것을 확인할 수 있었다.

• Steel and Composite Structures
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• 제36권2호
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• pp.197-211
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• 2020

Application of the steel ring as a type of seismic fuse has been one of the efforts made by researchers in recent years aiming to enhance the ductility of the bracing systems which in turn, possesses various advantages and disadvantages. Accordingly, to alleviate these disadvantages, an innovative bracing system with a diamond scheme equipped with a steel ring is introduced in this paper. In this system, the braces and yielding circular damper act in parallel whose main functionality is to increase ductility, energy absorption and mitigate drawbacks of the existing bracing systems, in which the braces and yielding circular damper act in parallel. To conduct the experimental tests, specimens with three types of rigid, semi-rigid and pinned connections were built and subjected to cyclic loading so that their performance could be analyzed. Promisingly, the results indicate both great applicability and efficiency of the proposed system in energy absorption and ductility. Moreover, it was concluded that as the braces and damper are in parallel, the use of a steel ring with smaller size and thickness would result in higher energy absorption and load-resisting capacity when compared to the other existing systems. Finally, to assess the potential of numerically modeling the proposed system, its finite element model was simulated by ABAQUS software and observed that there is a great agreement between the numerical and experimental results.

• Smart Structures and Systems
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• 제32권5호
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• pp.339-347
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• 2023

Both the first author and the company of the second author were involved, directly or indirectly, in the design stage of a permanent link between the bottom of the Italian peninsula and the nearby Sicily island. This ambitious project was left in stand-by from 2013 to 2023. The current political revival originates some thoughts on the updated desired performance of suspension bridges, without any immediate reference to that specific crossing. It is simply regarded as a starting point. After an update on recent worldwide realizations, the authors focus their attention on four basic aspects: the span length, the girder scheme, the foundation technology and the bridge runability. Eventually, structural control and monitoring aspects are discussed as potentially innovative options in designing suspension bridges with railway crossing.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
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• pp.64-68
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• 2001

This paper presents an innovative prototype of a new conceptual electromagnetic induction heated type far infrared rays radiant heating appliance using the voltage-fed edge-resonant ZVS-PWM high frequency inverter using IGBTs for food cooking and processing which operates under a constant frequency variable power regulation scheme. This power electronic appliance with soft switching high frequency inverter using IGBTs has attracted special interest from some advantageous viewpoints of safety, cleanliness, compactness and rapid temperature response, which is more suitable for consumer power electronics applications.

• 융합정보논문지
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• 제11권3호
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• pp.236-249
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• 2021

AR/VR 헤드셋의 대중화로 인하여 AR/VR 콘텐츠 산업이 많은 관심을 받고 있으나, 콘텐츠의 사용성을 저해하는 불편함이 산업의 성장에 나쁜 영향을 주고 있다. 본 연구는 이를 개선하기 위하여 AR/VR 콘텐츠의 사용성 평가를 위한 체계를 설계하고 해당 체계를 구동하기 위한 프로토타입 시스템의 구축을 시도하였다. 제안된 평가체계는 AR/VR 콘텐츠의 사용성에 연관된 다양한 항목을 개별적으로 평가한 후, 이를 종합하여 통합 사용성을 평가하는 체계이다. 이를 위하여 사용성에 관련된 항목을 안전성과 편의성 및 세부 항목에 맞추어 분류하고, 각 항목을 평가하기 위한 기준과 각 항목 및 요소의 중요도를 도출하는 방법, 그리고 이를 통합하여 최종 사용성을 평가하는 프로세스를 제안하였으며, 체계적 평가 수행을 위한 프로토타입 시스템을 구축하였다. 본 연구의 결과는 AR/VR 콘텐츠의 사용성 검증 기능 외에도 콘텐츠 제작 지침으로 작동하여 산업의 진흥에 크게 이바지할 수 있을 것으로 기대된다.

• Advances in Computational Design
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• 제1권1호
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• pp.61-77
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• 2016

Seismic performance of structures depends on the force flow mechanism inside the structure. Discontinuity regions, like beam-column joints, are often affected during earthquake event due to the complex and discontinuous load paths. The evaluation of shear strength and identification of failure mode of the joint region are helpful to (i) define the strength hierarchy of the beam-column sub-assemblage, (ii) quantify the influence of different parameters on the behaviour of beam-column joint and, (iii) develop suitable and adequate strengthening scheme for the joints, if required, to obtain the desired strength hierarchy. In view of this, it is very important to estimate the joint shear strength and identify the failure modes of the joint region as it is the most critical part in any beam-column sub-assemblage. One of the most effective models is softened strut and tie model which was developed by incorporating force equilibrium, strain compatibility and constitutive laws of cracked reinforced concrete. In this study, softened strut and tie model, which incorporates force equilibrium equations, compatibility conditions and material constitutive relation of the cracked concrete, are used to simulate the shear strength behaviour and to identify failure mechanisms of the beam-column joints. The observations of the present study will be helpful to arrive at the design strategy of the joints to ensure the desired failure mechanism and strength hierarchy to achieve sustainability of structural systems under seismic loading.

• 한국정보처리학회논문지
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• 제7권4호
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• pp.1279-1289
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• 2000

Recently, research activities for combining portable computer technology and wireless communication technology are in progress to realize mobile computing environment that designed to support mobile hosts in the existing network environments. For PCN environments, the location management strategies are particularly emphasized among various strategies necessary for the mobile computing environment. Location management strategy for PCN environment, which is mostly based on the IS-41 standards brings an issue that additional network traffics are generated to deliver updata messages to home location server whenever a mobile host changes its location server. In this paper, we propose an innovative updata strategy and a search strategy that resolves the problem shown in the IS-41 scheme for HLR/VLR structure of CDMA environments. Also, this paper presents the performance comparison of proposed scheme and scheme used in IS-41 obtained from a simulation. The simulation was conducted based on the number of messages, the rate of database accesses, and the number of hops visited when the location management scheme is executed.