• 대한통합의학회지
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• 제2권1호
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• pp.63-76
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• 2014

Purpose : The purpose of this study was to ascertain the effects of scapular stabilization exercise before rotator cuff surgery on pain and range of motion of middle-aged women. Method : 20 subjects who agreed on this experiment and were diagnosed with rotator cuff rupture participated in this study. Experimental groups were treated while 40 minutes a day, 5 times per week, for 2 weeks before surgery. The effects of scapular stabilization exercise were evaluated on VAS and range of motion. Collected data were analyzed with SPSS for windows ver. 20.0 program. One-way repeated ANOVA was used to examine a significance of each variable by time. Two-way repeated ANOVA was applied to examine a significance of the experimental group against the control group. In all statistical tests, the significance level was set by ${\alpha}=.05$. Result : The results of this study are as follows: 1) In both control and experimental groups, VASs were decreased significantly according to intervention period. There was no significant difference between VASs of two groups. 2) In both control and experimental groups, ROMs of shoulder, flexion, abduction and external rotation were increased significantly according to intervention period. In these three flexibility measurement variables, there were significant differences between ROMs of two groups. Conclusion : In view of all the results in this study, scapular stabilization exercise on before rotator cuff surgery proved to be effective in improving their pain, range of motion after surgery. It will be sufficient data to perform with their own exercise program.

• 한국산학기술학회논문지
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• 제12권11호
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• pp.5135-5142
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• 2011

이 논문에서는 도심 지역의 교통 제어 시스템의 동적 응답 성능 향상을 위하여 적응형 Q-Learning 강화 학습 메커니즘을 설계 하였다. 도로, 자동차, 교통 제어 시스템을 지능 시스템으로 모델링 하고, 자동차와 도로 사이는 무선 통신을 이용한 네트워크가 구성된다. 도로와 대로변에 필요한 센터네트워크가 설치되고 Q-Learning 강화 학습은 제안한 메커니즘의 구현을 위해 핵심 알고리즘으로 채택하였다. 교통 신호 제어 규칙은 자동차와 도로에서 매 시간 업데이트된 정보에 따라서 결정되며, 이러한 방법은 기존의 교통 제어 시스템에 비하여 도로를 효율적으로 활용하며 결과적으로 교통 흐름을 개선 한다. 알고리즘을 활용한 최적의 신호 체계는 온라인상에서 자동으로 학습함으로서 구현된다. 시뮬레이션을 통하여 제안한 알고리즘이 기존 시스템에 비하여 효율성 개선과 차량의 대개 시간에 대한 성능 지수가 모두 30% 이상 향상되었다. 실험 결과를 통하여 제안한 시스템이 교통 흐름을 최적화함을 확인하였다.

• 정보처리학회논문지C
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• 제11C권5호
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• pp.645-652
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• 2004

본 논문에서는 대역폭과 지연 파라미터를 참조하여 PG내의 토폴로지 정보를 하는 기법으로 라인 세그먼트를 이용하여 경계노드 사이의 다중 경로 정보를 하였다. 제안된 star 토폴로지 기법에서는 모든 경로를 찾는 대신 홉 카운트 기반의 깊이 우선 방식을 사용하여 효율적으로 다중 경로를 탐색할 수 있도록 하였다. 이를 위해 토폴로지 정보를 줄이고 다중링크 에 유연성을 부여하기 위하여 대역폭과 지연의 한 쌍으로 구성된 두 개의 라인 세그먼트를 이용하는 수정된 라인 세그먼트 기법을 제안하였다. 그리고, 이를 기존의 star 토폴로지에 적용한 효율적인 토폴로지 기법을 제안하였다. 제안된 기법의 성능을 평가하기 위해 기존의 star 기법과 호 성공율, 접근시간 및 크랭크 백율에 대하여 컴퓨터 시뮬레이션을 통해 비교 분석하였다. 시뮬레이션 분석결과 제안된 star TA 기법이 기존의 기법보다 성능이 향상됨을 알 수 있었다.

• Smart Structures and Systems
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• 제6권5_6호
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• pp.595-618
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• 2010

This paper describes the application of a wireless sensor network to a 31 meter-tall medieval tower located in the city of Trento, Italy. The effort is motivated by preservation of the integrity of a set of frescoes decorating the room on the second floor, representing one of most important International Gothic artworks in Europe. The specific application demanded development of customized hardware and software. The wireless module selected as the core platform allows reliable wireless communication at low cost with a long service life. Sensors include accelerometers, deformation gauges, and thermometers. A multi-hop data collection protocol was applied in the software to improve the system's flexibility and scalability. The system has been operating since September 2008, and in recent months the data loss ratio was estimated as less than 0.01%. The data acquired so far are in agreement with the prediction resulting a priori from the 3-dimensional FEM. Based on these data a Bayesian updating procedure is employed to real-time estimate the probability of abnormal condition states. This first period of operation demonstrated the stability and reliability of the system, and its ability to recognize any possible occurrence of abnormal conditions that could jeopardize the integrity of the frescos.

• Advances in aircraft and spacecraft science
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• 제4권2호
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• pp.145-167
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• 2017

The presented paper gives an overview of several projects addressing the experimental characterization and control of the buffet phenomenon on 3D turbulent wings in transonic flow conditions. This aerodynamic instability induces strong wall pressure fluctuations and therefore limits flight domain. Consequently, to enlarge the latter but also to provide more flexibility during the design phase, it is interesting to try to delay the buffet onset. This paper summarizes the main investigations leading to the achievement of open and closed-loop buffet control and its experimental demonstration. Several wind tunnel tests campaigns, performed on a 3D half wing/fuselage body, enabled to characterize the buffet aerodynamic instability and to study the efficiency of innovative fluidic control devices designed and manufactured by ONERA. The analysis of the open-loop databases demonstrated the effects on the usual buffet characteristics, especially on the shock location and the separation areas on the wing suction side. Using these results, a closed-loop control methodology based on a quasi-steady approach was defined and several architectures were tested for various parameters such as the input signal, the objective function, the tuning of the feedback gain. All closed-loop methods were implemented on a dSPACE device able to estimate in real time the fluidic actuators command calculated mainly from the unsteady pressure sensors data. The efficiency of delaying the buffet onset or limiting its effects was demonstrated using the quasi-steady closed-loop approach and tested in both research and industrial wind tunnel environments.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권8호
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• pp.2827-2848
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• 2021

Mobile Crowdsourcing (MCS) has become an emerging paradigm evolved from crowdsourcing by employing advanced features of mobile devices such as smartphones to perform more complicated, especially spatial tasks. One of the key procedures in MCS is to collect answers from mobile users (workers), which may face several security issues. First, authentication is required to ensure that answers are from authorized workers. In addition, MCS tasks are usually location-dependent, so the collected answers could disclose workers' location privacy, which may discourage workers to participate in the tasks. Finally, the overhead occurred by authentication and privacy protection should be minimized since mobile devices are resource-constrained. Considering all the above concerns, in this paper, we propose a lightweight and privacy-preserving answer collection scheme for MCS. In the proposed scheme, we achieve anonymous authentication based on traceable ring signature, which provides authentication, anonymity, as well as traceability by enabling malicious workers tracing. In order to balance user location privacy and data availability, we propose a new concept named current location privacy, which means the location of the worker cannot be disclosed to anyone until a specified time. Since the leakage of current location will seriously threaten workers' personal safety, causing such as absence or presence disclosure attacks, it is necessary to pay attention to the current location privacy of workers in MCS. We encrypt the collected answers based on timed-release encryption, ensuring the secure transmission and high availability of data, as well as preserving the current location privacy of workers. Finally, we analyze the security and performance of the proposed scheme. The experimental results show that the computation costs of a worker depend on the number of ring signature members, which indicates the flexibility for a worker to choose an appropriate size of the group under considerations of privacy and efficiency.

• International Journal of Computer Science & Network Security
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• 제21권2호
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• pp.66-76
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• 2021

The quality of the E-learning education in Saudi Arabia has been a major concern by many academicians, especially, and people in general as this platform has not been a priority for education. Not until recently, the world has been impacted by the Covid-19 pandemic, which makes every education institution shifted to the online platform to continue the education for the students. Thus, many studies on the perceptions on the online learning have been carried out, and though many are focusing on the perceptions by the education institutions' faculty and administration, there is a lack in the amount of study performed to analyse the students' perceptions of online learning during the pandemic time. The current study is conducted by utilising qualitative methods in order to collect information and investigate the students' perception regarding online learning during the pandemic Covid-19, based on their individual experiences. A number of fifteen (15) students were selected as respondents for the study, in which structured interviews were conducted by using a convenient sampling technique for data collection. Through the discussion, all of the positive and negative perceptions of online learning, as well as the factors contributing to those perceptions were identified. The results of the study found that the positive perceptions were contributed based on the flexibility, cost-effectiveness, availability of the electronic research databases, and well-designed online classroom interfaces. For the negative perceptions from using online learning platforms, the respondents informed that they were contributed by the lecturer's delayed feedback, lack of technical support by lecturers, low in self-esteem and self-motivation, feel isolated, one-way of educational methods, and poorly-designed class materials. Through the findings, the school's administration and lecturers would be able to know the struggles experienced by the students, and eventually come out with better solutions to improve their teaching methods.

• International Journal of Computer Science & Network Security
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• 제21권6호
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• pp.304-311
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• 2021

The relevance of the research involves outlining the need for modern professionals to acquire new competencies. In the conditions of rapid civilizational progress, in order to meet the requirements of the labor market in the knowledge society, there is a readiness for continuous training as an indicator of professional success. The purpose of the research is to identify the impact of various forms of application of information technologies for lifelong learning in order to provide the continuous self-development of each person without cultural or age restrictions and on the basis of rapid digital progress. A high level (96%) of need of the adult population in continuing education with the use of digital technologies has been established. The most effective ways to implement the concept of "lifelong learning" have been identified (educational camps, lifelong learning, mass open online courses, Makerspace activities, portfolio use, use of emoji, casual game, scientific research with iVR game, implementation of digital games, work in scientific cafes). 2 basic objectives of continuing professional education for adults have been outlined (continuous improvement of qualifications and obtaining new qualifications). The features of ICT application in adult education have been investigated by using the following methods, namely: flexibility in terms of easy access to ideas, solving various problems, orientation approach, functional learning, group or individual learning, integration of leisure, personal and professional activities, gamification. The advantages of application of information technologies for continuous education (economic, time, and adaptive) have been revealed. The concept of continuous adult learning in the context of digitalization has been concluded. The research provides a description of the structural principles of the concept of additional education; a system of information requests of the applicant, as well as basic technologies for lifelong learning. The research indicates the lack of comprehensive research in the relevant field. The practical significance of the research results lies in the possibility of using the obtained results for a wider acquaintance of the adult population with the importance of the application of lifelong learning for professional activities and the introduction of methods for its implementation in the educational policy of the state.

• Korean Chemical Engineering Research
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• 제59권3호
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• pp.443-449
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• 2021

전분과 구연산의 에스테르화 반응을 통한 가교화로 내수성 및 도포성이 우수한 생분해성 비산 방지용 박막소재를 제조하고 특성을 분석하였다. 이들 소재의 박막 형성 및 물성을 향상하기 위하여 PVA과 글리세린 등을 첨가하여 도포된 박막의 유연성을 확보하였다. 또한 원재료 및 첨가재의 농도, 온도 및 반응 시간에 따른 물에 대한 팽윤도 및 용해도와 같이 재료 기능성을 최적화하는 조건을 분석하였다. FT-IR 분석으로 전분과 구연산의 가교 반응을 확인하였으며, 이들 반응과정에서 단일 및 다중 에스테르화 반응이 동시에 일어남을 알 수 있었다. 가교된 전분-구연산 박막재료는 토양매립 후 12주가 지났을 때 95%가량 분해되었어 생분해성이 우수함을 알 수 있다.

• 신재생에너지
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• 제16권4호
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• pp.65-75
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• 2020

The value of tangible assets depreciates over their useful life and this depreciation should be adequately reflected in any tax or financial reports. However, the method used to calculate depreciation can impact the financial performance of solar projects due to the time value of money. Korean tax law stipulates only one method for calculating the depreciation of solar photovoltaic facilities: the straight-line method. Conversely, USA's tax law accepts other depreciation methods as solar incentives, including the modified accelerated cost recovery system (MACRS) and Bonus depreciation method. This paper compares different depreciation methods in the financial analysis of a 10 MW solar system to determine their effect on the financial results. When depreciation was calculated utilizing the MACRS and Bonus depreciation method, the internal rate of return (IRR) was 10.9% and 16.4% higher, respectively, than when the Korean straight-line depreciation method was used. Additionally, the increased IRR resulting from the use of the two US methods resulted in a 20.5% and 27.4% higher net present value, respectively. This shows that changing the depreciation calculation method can redistribute the tax amount during the project period, thereby increasing the discounted cash flow of the solar project. In addition to increasing profitability, USA's depreciation methods alleviate the uncertainty of solar projects and provide more flexibility in project financing than the Korean method. These results strongly suggest that Korean tax law could greatly benefit from adopting USA's depreciation methods as an effective incentive scheme.