• Smart Structures and Systems
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• 제32권5호
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• pp.297-308
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• 2023

Dynamic deflection is important for evaluating the performance of a long-span cable-stayed bridge, and its continuous measurement is still cumbersome. This study proposes a dynamic deflection monitoring method for cable-stayed bridge based on Bi-directional Long Short-term Memory (BiLSTM) neural network taking advantages of the characteristics of spatial variation of cable acceleration response (CAR) and main girder deflection response (MGDR). Firstly, the relationship between the spatial and temporal variation of the CAR and the MGDR is described based on the geometric deformation of the bridge. Then a data-driven relational model based on BiLSTM neural network is established using CAR and MGDR data, and it is further used to monitor the MGDR via measuring the CAR. Finally, numerical simulations and field test are conducted to verify the proposed method. The root mean squared error (RMSE) of the numerical simulations are less than 4 while the RMSE of the field test is 1.5782, which indicate that it provides a cost-effective and convenient method for real-time deflection monitoring of cable-stayed bridges.

• 한국구조물진단유지관리공학회 논문집
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• 제25권6호
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• pp.185-192
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• 2021

본 연구에서는 거푸집 패널이 부착된 실물 스케일의 중공슬래브 Mock-up을 제작하여 즉시 처짐 및 장기 처짐에 대한 플랫 플레이트 중공 슬래브의 안전성을 평가하고자 한다. 중공재가 적용된 Mock-up 실험체의 중공률은 24%로 설계하였다. 콘크리트 블록 하중 재하 시 슬래브의 가장 중앙부의 처짐인 No2의 경우 재하 시 처짐이 8.88mm 발생하였으며 이는 즉시 처짐에 대한 기준 값(l_n/240=17.93mm)에 비하여 안전한 값을 나타내고 있다. 3개월간 처짐 량 계측 결과, 중앙부 처짐 량은 초기 처짐에서 6.792mm 더 추가되어 처짐이 발생하였지만, 이는 국내 구조 기준에서 제시하고 있는 사용하중에 의한 기준 값을 만족하고 있는 것으로 나타났다.

• The Journal of Korean Physical Therapy
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• 제24권6호
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• pp.405-408
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• 2012

Purpose: We examined the effect of dual-task and single-task training on serial reaction time (SRT) task performance to determine whether SRT is based more on motor or perception in a dual-task. Methods: Forty healthy adults were divided into two groups: the dual-task group (mean age, $21.8{\pm}1.6$ years) and the single-task group (mean age, $21.7{\pm}1.6$ years). SRT task was conducted total 480 trial. The four figures were presented randomly 16 times. A unit was set as 1 block that would repeat 10 times. Thus, there were a total of 160 trials for each of the three color conditions. The dual-task group performed an SRT task while detecting the color of a specific shape. The end of the task, subjects answered the specific shape number; the single-task group only performed the SRT task. The study consisted of three parts: pre-measurement, task performance, and post-measurement. Results: Differences of pre and post reaction time between two group was higher for the dual-task group as compared to the single task group and there was a significant interaction between time and group (p<0.05). Conclusion: Our results indicate that. short term period SRT is not quiet effective under dual-task conditions, individuals need additional cognitive processes to successfully navigate a task This suggests that dual-task training might not be appropriate for motor learning enhancement, at least when the training is over a short period.

• IEIE Transactions on Smart Processing and Computing
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• 제6권1호
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• pp.1-9
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• 2017

This paper proposes to improve the performance of a strap down inertial navigation system using a foot-mounted low-cost inertial measurement unit/magnetometer by configuring an attitude and heading reference system. To track position accurately and for attitude estimations, considering different dynamic constraints, magnetic measurement and a zero velocity update technique is used. A conventional strap down method based on integrating angular rate to determine attitude will inevitably induce long-term drift, while magnetometers are subject to short-term orientation errors. To eliminate this accumulative error, and thus, use the navigation system for a long-duration mission, a hybrid configuration by integrating a miniature micro electromechanical system (MEMS)-based attitude and heading detector with the conventional navigation system is proposed in this paper. The attitude and heading detector is composed of three-axis MEMS accelerometers and three-axis MEMS magnetometers. With an absolute algorithm based on gravity and Earth's magnetic field, rather than an integral algorithm, the attitude detector can obtain an absolute attitude and heading estimation without drift errors, so it can be used to adjust the attitude and orientation of the strap down system. Finally, we verify (by both formula analysis and from test results) that the accumulative errors are effectively eliminated via this hybrid scheme.

• 한국사회복지학
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• 제45권
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• pp.126-155
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• 2001

It has been 5 years since evaluation systems were introduced to the social welfare field in Korea. More than half of social welfare agencies (617 out of 1,267) were evaluated in the past two years. Most areas of the agencies were the target of an extensive evaluation in 2000. As "the Evaluation Era" has come, problems were raised especially regarding the Accreditation system of the Ministry of Health and Social Welfare. More specifically, the problems were related to operation and management of the evaluation systems including the issue of evaluators' objectivity and fairness. In addition, evaluation costs have been too high to the government. The evaluation systems of OECD nations including the United States were quite different. These nations have used the Performance Measurement in order to secure the objectivity and the fairness. Although the quantity of information was limited compared to that of the Accreditation system, these nations have taken the lead in the governmental evaluation. In this context, this study compared social welfare evaluation systems between Korea and the United States. It presented the current status and problems of the Accreditation system of the Ministry of Health and Social Welfare, discussed the American Performance Measurement and its limitations, and compared the strengths and weaknesses of the two evaluation systems. In addition, this study suggested the strategies of Korean evaluation systems in the long term as well as in the short term.

• 한국전산구조공학회논문집
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• 제30권3호
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• pp.249-254
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• 2017

본 논문에서는 가속도계와 속도계를 활용한 단기 동적변위 산정기법을 소개한다. 본 기법에서 변위는 측정된 가속도와 속도 데이터를 칼만필터 기반 실시간 융합 알고리즘에 적용하여 추정된다. 기존 변위센서(LVDT, LDV, Vision 등)는 고정된 지지점과 설치를 위해 별도의 가설물을 필요로 했기 때문에 지진 발생 시나 해상교량 적용에 한계가 있었다. 또한 Laser/Vision 기반 센서의 경우 시야확보가 어려운 경우 활용이 제한된다. 본 기법에서는 부착식 센서인 가속도계와 속도계를 활용하기 때문에, 고정된 지지점이 필요 없을뿐더러 부착만 되면 시야확보 여부로부터 자유롭다. 따라서, 지진, 해상교량뿐만 아니라 화재 시에도 적용 가능하다. 변위추정을 위해 누적되는 가속도의 이중적분 오차는 속도 계측치로 보정되며, 실험실 규모 테스트를 통해 해당 기법을 검증하였다.

• 한국전자통신학회논문지
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• 제15권2호
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• pp.291-298
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• 2020

수화는 청각 장애인이 다른 사람들과 의사소통할 수 있도록 설계된 것이다. 그러나 수화는 충분히 대중화되어 있지 않기 때문에 청각 장애인이 수화를 통해서 일반 사람들과 원활하게 의사소통하는 것은 쉽지 않은 문제이다. 이러한 문제점에 착안하여 본 논문에서는 웨어러블 컴퓨팅 및 딥러닝 기반 미국식 수화인식 시스템을 설계하고 구현하였다. 이를 위해서 본 연구에서는 손등과 손가락에 장착되는 총 6개의 IMUs(Inertial Measurement Unit) 센서로 구성된 시스템을 구현하고 이를 이용한 실험을 수행하여 156개 특징이 수집된 데이터 추출을 통해서 총 28개 단어에 대한 미국식 수화 인식 방법을 제안하였다. 특히 LSTM (Long Short-Term Memory) 알고리즘을 사용하여 최대 99.89%의 정확도를 달성할 수 있었고 향후 청각 장애인들의 의사소통에 큰 도움이 될 것으로 예상된다.

• Water Engineering Research
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• 제1권3호
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• pp.233-242
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• 2000

A system for regularly appraising the reliability of streamflow data, KORSAS (KOwaco's Regular Streamflow Appraising System) was developed on PC based Windows for hydrological specialists and engineers working in the Korea Water Resources Corporation (KOWACO). The reliability of streamflow rates can be evaluated with KORSAS in various as pects according to the evaluation duration and method. The former being selected as short term (event based) or long term(continus based), and the latter being classified into comparison methods of flow measurement, other stations results, and simulation. Rainfall-runoff models can be used together with KORSAS in order to evaluate the reliability of observed flow data by comparing with simulated flow data. The objective of this study is to develop a systematic methodology in various aspects to evaluate the reliability of streamflow data regularly.

• 한국건축시공학회지
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• 제9권2호
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• pp.63-68
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• 2009

Construction Performance measurement and management has been interested by construction practitioners. However, current construction project management practices are related to short-term improvement plans rather than long-term and systematic approaches based upon performance analysis. AR a result, there is a need for developing of a collaborative plan over project life cycle. Therefore, this paper reviews extensive literature and proposes the construction performance estimating model using a system dynamics. The paper proposes casual maps for planning, design, procurement, and construction phases. Each casual map includes all performance indicators and factors that impact on performance directly or indirectly. These casual maps that were developed by system thinking will enhance the understanding of the relationships among performances and factors. After further data gathering, these models can be used to estimate construction performance and eventually these will save project costs and shorten project schedule.

• 디지털융복합연구
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• 제7권2호
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• pp.51-62
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• 2009

Most studies of organizational effectiveness previously done, have measured financial performance such as productivity, efficiency or subjective performance such as a commitment, satisfaction, and turnover intention of employees. However, these measurements have limitations to evaluate a organizational effectiveness in recent knowledge information era because evaluation of organizational effectiveness in knowledge-based society needs measurements in various aspects such as financial, customer, internal business process, and learning and growth. The purpose of this study is to overcome these problems and to introduce an appropriate system for evaluation of organizational effectiveness under knowledge management paradigm. In this paper, we suggest a Balanced Scorecard(BSC) as a new measurement standard of organizational effectiveness in a knowledge information era. The balanced scorecard is designed to help firms that have historically overemphasized short-term financial performance. When measuring organizational effectiveness through Balanced Scorecard(BSC) suggested by Kaplan and Norton[31], it is to present the measurement indices that can cover the limitation of the past evaluation indices of organizational effectiveness.