• Journal of the Korean Society for Precision Engineering
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• v.4 no.3
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• pp.52-59
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• 1987

The flatness of a precision surface plate is generally measured by using precision angular measuring instruments such as laser interferometers, autocollimators and electronic levels. Since these instruments are expensive and measurement procedures are complex, such methods are not widely used in industries. In this study, an electronic micrometer that is easy to use and inexpensive to produce was developed in order to solve this problem. The flatness of a black granite surface plate, measured using this device was compared with the values obtained by using the conventional three methods. The results were consistent within ${\pm}1{\mu}m$. It proves that the flatness measuring method using electronic micrometers can be utilized for quantitative measurement. An accessory device that can improve the precision of measurement by attaching to the electronic micrometer was also designed and fabricated.

• Journal of muscle and joint health
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• v.15 no.1
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• pp.24-32
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• 2008

Purpose: This study was conducted to develop an advanced aquatic exercise program for the patients with arthritis. Method: This study subjects were six aquatic exercise program instructors of Korean Society Muscle and Joint Health. They withheld several meeting to develop advanced aquatic exercise program. Results: The basic aquatic exercise program which were used since 1996 in Korea consisted of 9 units of ROM exercise in water. The advanced aquatic exercise program for the patients with arthritis consist of 12 units with complex and resistive exercise. Conclusion: This preliminary advanced aquatic exercise program for the patients with arthritis should be investigate for the effectiveness to build a more concrete evidence and utilization.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.2
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• pp.89-97
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• 2009

Embedded systems widely used in ubiquitous environments usually employ an event-driven programming model instead of thread-based programming model in order to create a more robust system that uses less memory. However, as the software for embedded systems becomes more complex, it becomes hard to program as a single event handler using the event-driven programming model. This paper discusses the implementation of non-preemptive real-time scheduling theory for the design of embedded systems. To this end, we present an efficient schedulability test method for a given non-preemptive task set using a sufficient condition. This paper also shows that the notion of sub-tasks in embedded systems can overcome the problem of low utilization that is a main drawback of non-preemptive scheduling.

• Journal of Power Electronics
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• v.19 no.6
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• pp.1566-1574
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• 2019

Maximum power point tracking (MPPT) under the partial shading condition is a challenging research topic for photovoltaic systems. Shaded photo-voltaic module result in complex peak patterns on the power versus voltage curve which can misguide classical MPPT algorithms. Thus, various kinds of global MPPT algorithms have been studied. These have typically consisted of partial shading detection, global peak search and MPPT. The conventional partial shading detection algorithm aims to detect all of the occurrences of partial shading. This results in excessive execution of global peak searches and discontinuous operation of the MPPT. This in turn, reduces the achievable power for the PV module. Based on a theoretical investigation of power verse voltage curve patterns under various partial shading conditions, it is realized that not all the occurrences of partial shadings require a global peak search. Thus, an intelligent partial shading detection algorithm that provides exact identification of global peak search necessity is essential for the efficient utilization of solar energy resources. This paper presents a new partial shading determinant algorithm utilizing adaptive threshold levels. Conventional methods tend to be too sensitive to sharp shading patterns but insensitive to smooth patterns. However, the proposed algorithm always shows superb performance, regardless of the partial shading patterns.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.147-147
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• 2018

In this article, we use an open source software library: TensorFlow, developed for the purposes of conducting very complex machine learning and deep neural network applications. However, the system is general enough to be applicable in a wide variety of other domains as well. The proposed model based on a deep neural network model, LSTM (Long Short-Term Memory) to predict the river water level at Okcheon Station of the Guem River without utilization of rainfall - forecast information. For LSTM modeling, the input data is hourly water level data for 15 years from 2002 to 2016 at 4 stations includes 3 upstream stations (Sutong, Hotan, and Songcheon) and the forecasting-target station (Okcheon). The data are subdivided into three purposes: a training data set, a testing data set and a validation data set. The model was formulated to predict Okcheon Station water level for many cases from 3 hours to 12 hours of lead time. Although the model does not require many input data such as climate, geography, land-use for rainfall-runoff simulation, the prediction is very stable and reliable up to 9 hours of lead time with the Nash - Sutcliffe efficiency (NSE) is higher than 0.90 and the root mean square error (RMSE) is lower than 12cm. The result indicated that the method is able to produce the river water level time series and be applicable to the practical flood forecasting instead of hydrologic modeling approaches.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2019.05a
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• pp.448-450
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• 2019

Multipath TCP (MPTCP) is a standardized transport layer protocol for maximizing the use of finite network resources by using multiple interfaces simultaneously. If the characteristics of each path are the same, there is an advantage in terms of stability and bandwidth utilization compared to the existing single TCP. However, if the path characteristics are different, the performance is lower than that of a single TCP. There are many complex reasons for this, but one of the biggest impacts is the bufferbloat, which dramatically increases the latency. In this paper, we implemented an algorithm that improved MPTCP performance degradation due to bufferbloat in Linux - based testbed and compared performance with existing MPTCP scheduler.

• Journal of Powder Materials
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• v.27 no.6
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• pp.477-483
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• 2020

Metal-organic frameworks (MOFs) are of significant interest because of their high porosity, which facilitates their utilization in gas storage and catalysis. To enhance their current properties in these applications, it is necessary to elucidate the interactions between molecules in a confined environment that differ from those in bulk conditions. Herein, we study the confined molecular interaction by investigating the solvent-dependent photophysical properties of two different-sized molecules inside MOF-5. Ruthenium tris-bipyridine (Rubpy) and coumarin 153 (C153) are encapsulated in MOF-5. Rubpy with MOF-5 (Rubpy@MOF) is prepared by building MOF-5 around it, resulting in limited space for solvent molecules in the pores. The smaller C153 is encapsulated in the preformed MOF-5 (C153@MOF) by simply soaking the MOF in a concentrated C153 solution. C153@MOF permits more space for solvent molecules in the pore. Their characteristic absorption and emission spectra are examined to elucidate the confined molecular interactions. Rubpy@MOF and C153@MOF exhibit different spectral shifts compared to the guest molecules under bulk conditions. This discrepancy is attributed to the different micro-environments inside the pores, derived from confined host-guest interactions in the interplay of solvent molecules.

• Journal of Information Science Theory and Practice
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• v.9 no.2
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• pp.33-46
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• 2021

The purpose of this paper is to analyze the case of 'drive-thru' services newly introduced and tried in libraries in Korea under the influence of COVID-19, and to develop and propose a service model so that this service can be continuously applied to all libraries in the future. Therefore, the method of study was selected and analyzed by selecting one of the representative libraries that provide related services in Seoul Special City, Incheon Metropolitan City, and Anyang City of Gyeonggi Province. In addition, a focus group interview was conducted with twelve people in charge to find a way to apply the drive-thru service to the library. As a result, the library's drive-thru service is a way to fulfill the library's original purpose of providing information materials while minimizing faceto-face contact with users. It was concluded that it is a suitable method for a library of complex buildings, where there is a lack of parking space. In addition, it was deduced that it may be one of the ways to use the library efficiently for office workers who are unable to use library services during the opening hours. Therefore, if the drive-thru service is implemented according to the developed model, it is expected to increase the library visit rate and data utilization rate.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.8
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• pp.375-386
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• 2021

The purpose of the research was to explore the factors which affect service innovation in organizations and how the utilization of resources can improve organizational performance, and gain a competitive advantage by adopting numerous innovative practices. This study hypothesizes Service Innovation Readiness (SIR) to consist of Strategic Alignment favoring Service Innovation (SASI) and Empowering Structure for Service Innovation (ESSI), which regulate the organization's preparedness to adopt service innovation changes. Six dimensions were identified and analyzed to understand their effects on SASI and ESSI. A structured questionnaire on a 5-point Likert scale was used to collect data from the selected hospitals of Saudi Arabia. The research results contribute considerably to the subject matter by theorizing SIR and the complex variable settings essential for embracing SI. This research also provides some understanding of the service innovation management dimension through a complete assessment that measures the organization's readiness and attempts to direct organizations' efforts to achieve and sustain competitive advantage. The study conducted is unique in the current geographic limits and has explored numerous SI areas of an organization's readiness to adopt service innovation.

• Korean Medical Education Review
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• v.23 no.1
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• pp.11-22
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• 2021

This review of the literature explored the experiences and effects of peer-assisted learning in basic medical education. Peer-assisted learning is most commonly utilized to teach clinical skills (including technical skills) and medical knowledge (76.4%). It has also been used, albeit less frequently, to facilitate small-group discussions including problem-based learning, to promote students' personal and professional development, to provide mentoring for career development and adaptation to school, to give tutoring to at-risk students, and to implement work-based learning in clinical settings. Near-peer learning is a common type. The use of active learning techniques and digital technology has been increasingly reported. Students' leadership had frequently been described. Student tutor training, programs for teaching skills, institutional support, and assessments have been conducted for effective peer-assisted learning. There is considerable positive evidence that peer-assisted learning is effective in teaching simple clinical skills and medical knowledge for tutees. However, its effects on complex skills and knowledge, small-group discussions, personal and professional development, peer mentoring, and work-based learning have rarely been studied. Additionally, little evidence exists regarding whether peer-assisted learning is effective for student tutors. Further research is needed to develop peer-assisted learning programs and to investigate their learning effects on student tutors, small-group discussion facilitation, personal and professional development, peer mentoring, and peer-led work-based learning in the clinical setting in South Korea. Formal programs and system advancement for a student-led learning culture is needed for effective peer-assisted learning.