• 드라이브 ㆍ 컨트롤
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• 제13권4호
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• pp.52-58
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• 2016

The mechanical design for biped walking of a humanoid robot doing the Argentina Tango is presented in this paper. Biped walking has long been studied in the area of robotic locomotion. The aim of this paper is to implement an Argentina Tango dancer-like walking motion with a humanoid robot by using a trajectory generation scheme. To that end, this paper uses blending polynominals whose parameters are determined based on PSO (Particle Swarm Optimization) according to conditions that make the most of the Argentina Tango's characteristics. For the stability of biped walking, the ZMP (Zero Moment Point) control method is used. The feasibility of the proposed scheme is evaluated by simulating biped walking with the 3D Simscape robot model. The simulation results show the validity and effectiveness of the proposed method.

• 한국군사과학기술학회지
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• 제20권5호
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• pp.708-716
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• 2017

We deal with the target selection in seeker-detection image through network, using the detection information from aerial vehicle and the target information from surveillance and reconnaissance system. Especially, we constrain the sea battle environment, where it is difficult to perform scene-matching rather than land. In this paper, we suggest the target selection algorithm based on the confidence estimation with respect to distance and size. In detail, we propose the generation method of reference point for distance evaluation, and we investigate the effect of pixel margin and target course for size evaluation. Finally, the proposed algorithm is simulated and analyzed through several scenarios.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.435-437
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• 2004

In this paper, we aim to design and implement supporting IPv6 Bluetooth Access point(AP) in Linux. Bluetooth is a cable replacement technology designed for short range ad-hoc connections, which most likely change the way we handle and access information in the near future. In Personal Area Network(PAN) mobile devices need many IP address space, then we need next generation Internet Protocol(IPv6). We designed Bluetooth Access Point with Bluetooth stack and MAC bridge function in Linux. The implementation tested on Linux system based on Bluetooth Access Point with other Bluetooth devices.

• Journal of Communications and Networks
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• 제18권2호
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• pp.150-161
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• 2016

Coordinated multi-point transmission (CoMP) techniques are being touted as enabling technologies for interference mitigation in next generation heterogeneous wireless networks (HetNets). In this paper, we present a comparative performance study of uplink (UL) CoMP algorithms for the 3GPP LTE HetNets. Focusing on a distributed and functionally-split architecture, we consider six distinct UL-CoMP algorithms: 1. Joint reception in the frequency-domain (JRFD) 2. Two-stage equalization (TSEQ) 3. Log-likelihood ratio exchange (LLR-E) 4. Symmetric TSEQ (S-TSEQ) 5. Transport block selection diversity (TBSD) 6. Coordinated scheduling with adaptive interference mitigation (CS-AIM) where JRFD, TSEQ, S-TSEQ, TBSD and CS-AIM are our main contributions in this paper, and quantify their relative performances via the post-processing signal-to-interference-plus-noise ratio distributions.We also compare the CoMP-specific front-haul rate requirements for all the schemes considered in this paper. Our results indicate that, with a linear minimum mean-square error receiver, the JRFD and TSEQ have identical performances, whereas S-TSEQ relaxes the front-haul latency requirements while approaching the performance of TSEQ. Furthermore, in a HetNet environment, we find that CS-AIM provides an attractive alternative to TBSD and LLR-E with a significantly reduced CoMP-specific front-haul rate requirement.

• 대한간호학회지
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• 제39권2호
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• pp.259-269
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• 2009

Purpose: The aim of this study was to develop a breast feeding adaptation scale (BFAS) to evaluate adaptation to breastfeeding for breastfeeding mothers and their infants and to test the validity and reliability of the instrument. Methods: The study was conducted as follows: application of the conceptual framework, identification of the content domains, items generation, and test of validity and reliability. In order to test validity and reliability, two panels of experts reviewed items and subcategories of the preliminary questionnaire and then data were collected from 329 mothers who were up to 4 weeks postpartum and breastfeeding. Descriptive statistics, t-test, factor analysis, and Cronbach's alpha were used to analyze the data. Results: The conceptual framework was based on the Roy adaptation model. The content domains were developed via literature review, review of instruments, and data acquired from the interviews of breastfeeding mothers and nurses. A total of 69 items belonging to 8 domains were generated. A reduction to 44 preliminary items was accomplished through content validity analysis. Factor analysis extracted 8 factors with a total of 27 items on a 5-point Likert scale. Content validity, construct validity, criterion validity, and reliability of the BFAS were established. Conclusion: The newly developed BFAS is a reliable and valid instrument with which the adaptation of breastfeeding mothers and their infants to the breastfeeding behavior can be evaluated.

• Industrial Engineering and Management Systems
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• 제8권4호
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• pp.239-246
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• 2009

This paper deals with the makespan minimization problem of job shops. The problem is known as one of hard problems to optimize, and therefore, many heuristic methods have been proposed by many researchers. The aim of this study is also to propose a heuristic scheduling method for the problem. However, the difference between the proposed method and many other heuristics is that the proposed method is based on depth-first branch and bound, and thus it is possible to find an optimal solution at least in principle. To accelerate the search, when a node is judged hopeless in the search tree, the proposed flexible branch and bound method can indicate a higher backtracking node. The unexplored nodes are stored and may be explored later to realize the strict optimization. Two methods are proposed to generate the backtracking point based on the critical path of the current best feasible schedule, and the minimum lower bound for the makespan in the unexplored sub-problems. Schedules are generated based on Giffler and Thompson's active schedule generation algorithm. Acceleration of the search by the flexible branch and bound is confirmed by numerical experiment.

• 한국지능시스템학회논문지
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• 제25권3호
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• pp.299-305
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• 2015

Global environmental concerns and the ever increasing need of energy, coupled with steady progress in renewable energy technologies, are opening up new opportunities for utilization of renewable energy resources. Distributed electricity generation is a suitable option for sustainable development thanks to the load management benefits and the opportunity to provide electricity to remote areas. Solar energy being easy to harness, non-polluting and never ending is one of the best renewable energy sources for electricity generation in present and future time. Due to the random and intermittent nature of solar source, PV plants require the adoption of an energy storage and management system to compensate fluctuations and to meet the energy demand during night hours. This paper presents an efficient, economic and technical model for the design of a MPPT based grid connected PV with battery storage and management system. This system satisfies the energy demand through the PV based battery energy storage system. The aim is to present PV-BES system design and management strategy to maximize the system performance and economic profitability. PV-BES (photovoltaic based battery energy storage) system is operated in different modes to verify the system feasibility. In case of excess energy (mode 1), Li-ion batteries are charged using CC-CV mechanism effectively controlled by fuzzy logic based PID control system whereas during the time of insufficient power from PV system (mode 2), batteries are used as backup to compensate the power shortage at load and likewise other modes for different scenarios. This operational mode change in PV-BES system is implemented by State flow chart technique based on SOC, DC bus voltages and solar Irradiance. Performance of the proposed PV-BES system is verified by some simulations study. Simulation results showed that proposed system can overcome the disturbance of external environmental changes, and controls the energy flow in efficient and economical way.

• 한국수산과학회지
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• 제34권6호
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• pp.705-712
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• 2001

다방향불규칙파 조파장치를 이용하여 평면수조내의 발생파의 특성과 목표스펙트럼의 재현성 및 대표파의 통계적인 안정과 선형적인 관계를 검토하여 유효조파영역 및 모형구조물의 설치대상 영역을 검정하였다. 주요한 결과를 요약하면 다음과 같다. 다방향불규칙파에 의한 발생파의 특성과 목표스펙트럼의 재현성은 양호한 결과를 얻었으며, 이들 결과로부터 유효조파영역 및 대표적인 파랑의 재현성이 높은 영역을 설정할 수 있었다. 유효조파영역에서 얻어진 관측자료인 대표파는 통계적으로 안정하였으며, spectrum peakedness parameter $Q_p$와 평균 run-length, $Q_p$와 $U_r$로서 대표파의 선형적인 관계를 나타낼 수 있었다.

• 한국측량학회지
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• 제32권2호
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• pp.109-115
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• 2014

본 연구에서는 Han(2013)이 제안한 메모리 효율적인 옥트리를 기반으로 메인 메모리의 크기에 근접하거나 초과하는 3차원 포인트 클라우드로부터 옥트리를 생성하고 3차원 포인트를 탐색하기 위한 방법론을 제시하고자 한다. 이를 위하여 3차원 포인트 클라우드를 메인 메모리에 저장하여 참조하는 방법 대신 하드디스크의 파일을 직접적으로 참조하는 방법을 제안하였다. 아울러 메인 메모리에 구현된 옥트리를 파일로 저장하고 복원함으로써 옥트리 재현 시간을 줄이는 방법을 제안하였다. 메모리참조 방식과 제안된 파일참조 방식을 실제 터널에서 취득한 1800만 개의 3차원 포인트로 구성된 자료와 3억 개로 구성된 자료에 적용하였다. 결과로 옥트리 생성 및 3차원 포인트 탐색시 1800만 개로 구성된 자료에 대해서는 메모리참조 방식이 파일참조 방식보다 월등히 빠른 속도를 나타내었다. 3억 개로 구성된 자료에 대해서는 메모리참조 방식으로는 옥트리를 생성할 수 없는 반면 파일참조 방식으로는 옥트리 생성 및 3차원 포인트 탐색이 가능하였다. 최적의 탐색 속도를 위한 목표 단계의 옥트리는 생성할 수 없었지만 3억 개가 넘는 3차원 포인트를 탐색할 수 있다는데 의미를 둘 수 있다. 아울러 옥트리를 재현하기 위해 소요되는 시간은 옥트리를 생성하기 위한 시간의 3% 내외로서 제안된 방식이 매우 효율적임을 확인할 수 있었다.

• 대한치과보철학회지
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• 제45권1호
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• pp.21-33
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• 2007

Statement of problem: The esthetic component of dental care has become increasingly more important, while new tooth-colored materials are continually marketed. Various new indirect composite materials have been developed with required advantages. The most recent development in the indirect composites has been the introduction of the second-generation laboratory composite or poly-glass materials. They are processed by different laboratory techniques based on combinations of heat, pressure, vacuum and light polymerization. Although, second generation products became available in 1995, their characteristics and clinical performance have not been adequately investigated. Purpose: The aim of this study was to measure the mechanical properties of the second generation indirect resin system and compare these with an existing universal direct composite resin. Material and method: In this study four indirect composite material (Adoro LC, BelleGlass HP, Tescera, Synfony) were tested for flexural strength, wear resistance, hardness and their degree of conversion against Z250, a light cure direct composite. Results: Within the limitations of this study, the following conclusions were drawn: 1. From the abrasion wear result, Adoro showed the least volume loss while Synfony showed the greatest volume loss. Z250 and BelleGlass HP didn't show significant difference (p>0.05), but they showed significant difference with other groups (p<0.05). From the attrition wear, BelleGlass HP showed the least volume loss and it didn’t show significant difference with Tescera (p>0.05). While Synfony showed the greatest volume loss that it showed significant difference with other groups (p>0.05). 2. Mean values of flexural strength by means of three point bending test was in the order of Z250, Adoro, Belleglass HP, Tescera and Synfony. Mean elastic modulus was in the order of Z250, BelleGlass HP, Tescera, Adoro and Synfony. 3. The result of Vicker‘s microhardness value showed that significantly higher value in Z250 (p<0.05), and is in the order of BelleGlass HP, Tescera, Adoro and Synfony. 4. The degree of conversion measured by FT-IR showed significantly higher value in BelleGlass HP (p<0.05), and is in the order of Adoro, Synfony, Tescera and Z250. Conclusion: Significant differences were found in the flexural strength, wear resistance, hardness and their degree of conversion.