• Structural Engineering and Mechanics
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• 제43권3호
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• pp.273-285
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• 2012

Structural reanalysis is frequently used to reduce the computational cost during the process of design or optimization. The supports can be regarded as the design variables in various types of structural optimization problems. The location, number, and type of supports may be varied in order to yield a more effective design. The paper is focused on structural static reanalysis problem with added supports where some node displacements along axes of the global coordinate system are specified. A new approach is proposed and exact solutions can be provided by the approach. Thus, it belongs to the direct reanalysis methods. The information from the initial analysis has been fully exploited. Numerical examples show that the exact results can be achieved and the computational time can be significantly reduced by the proposed method.

• 융합경영연구
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• 제7권3호
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• pp.43-49
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• 2019

Purpose - This paper empirically investigates what factors contribute to management decisions by corporate governance in the Korean stock market. In the paper, dividends and investments were imployed as management decisions and major stockholders' shares and foreign investors' shares were used as corporate governance. Research design, data, and Methodolog - Samples are constructed by manufacturing firms listed on the stock market of Korea as well as those who settle accounts in December from 2001 to 2018. Financial institutions are excluded from the sample as their accounting procedures, governance and regulations differ. This study adopted the panel regression model to assess the sample construction including yearly and cross-sectional data. Results - This results support the literatures that major shareholders showed insignificance to dividends, positive significance to investment in financially unconstrained firms and negative significance to investment in financially constrained firms. Whereas foreign investors favor firms to increase dividends but they decrease investments only in financially constrained firms. Conclusion - This paper documented evidence that financial constrained firms use dividends for their investment and foreign investors decrease investments under financial constraints. But for dividends decisions, foreign investors give significant positive impacts irrespective of financial constraints.

• 산업공학
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• 제12권1호
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• pp.56-67
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• 1999

This paper is about implementation issues for use of the Internet technology in education. An examination of the current status of virtual university provides guidance for subsequent prototype development. A virtual university is the Internet based process by which students increase their specific knowledge and skills via electronic interaction with content and people. Virtual university enables colleges and universities to provide students and faculty with network access to courseware and educational materials on multimedia servers free from time and geography constraints. In this paper, we present a prototype instruction support system (ISS). The ISS consists of the following components in architecture: Internet, software, hardware, database systems, users, and workflow. The ISS also assists several functions as follows: lecture notes, register processes, attendance checks, built-in boards, grading systems, questions and answers, electronic libraries, chats, and search engines. Our work will provide a guideline for the development of a virtual classroom for distance education and learning.

• Tribology and Lubricants
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• 제39권3호
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• pp.94-101
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• 2023

Automotive wheel bearings are a critical component of vehicles that support their weight and facilitate rotation. Life and stiffness are significant performance characteristics of wheel bearings. Designing wheel bearings involves finding optimal design variables that satisfy both performances. CO₂ emission reduction and fuel efficiency regulations attribute to the recent increase in design requirements for lightweight and compact automotive parts while maintaining performance. However, achieving a design that maintains performance while reducing weight poses challenges, as performance and weight are generally inversely proportional. In this study, we perform design optimization of automotive wheel bearings considering life and stiffness. We develop a program that calculates the basic rated life and modified rated life based on international standards for evaluating the life of wheel bearings. We develop a regression equation using regression analysis to address the time-consuming stiffness analysis during repetitive analysis. We perform ANOVA and main effect analyses to understand the statistical characteristics of the developed regression equation. Furthermore, we verify its reliability by comparing the predicted and test results. We perform design optimization using the developed life prediction program, stiffness regression equation and weight regression equation. We select bearing specifications and geometry as design variables, weight as the cost function, and life and stiffness as constraints. Through design optimization, we investigate the influence of design variables on the cost function and constraints by comparing the initial and optimal design values.

• International Journal of Computer Science & Network Security
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• 제21권12호
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• pp.137-142
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• 2021

Distance learning universities provide online course content. The main methods of providing class contents are on-demand and live-streaming. This means that students are not restricted by time or space. The advantage is that students can take the course anytime and anywhere. Therefore, unlike commuting students, there is no commuting time to the campus, and there is no natural process required to take classes. However, despite this convenient situation, the attendance rate and graduation rate of distance learning universities tend to be lower than that of commuting universities. Although the course environment is not the only factor, students cannot obtain a bachelor's degree unless they fulfill the graduation requirements. In both commuter and distance learning universities, taking classes is an important factor in earning credits. There are fewer time and space constraints for distance learning students than for commuting students. It is also easy for distance learning students to take classes at their own timing. There should be more ease of learning than for students who commute to school with restrictions. However, it is easier to take a course at a commuter university that conducts face-to-face classes. I thought that the reason for this was that commuting to school was a part of the process of taking classes for commuting students. Commuting to school was thought to increase the willingness and motivation to take classes. Therefore, I thought that the inconvenient constraints might encourage students to take the course. In this research, I focused on the act of commuting to school by students. These situations are also applied to the distance learning environment. The students have physical time constraints. To achieve this goal, I will implement a course restriction method that aims to promote the willingness and attitude of students. Therefore, in this paper, I have implemented a virtual school system called "virtual go to school (VG2S)" that reflects the actual route to school.

• 경영과학
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• 제32권4호
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• pp.19-28
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• 2015

This study presents a mathematical programming model to develop production planning in the manufacturing processes for photovoltaic silicon ingots and wafers. The model is formulated as a linear programming model that maximizes total growth margin, which is composed of production cost, inventory cost, shortage cost, and sales profit while considering the constraints associated with the production environments of photovoltaic materials. In order to demonstrate the utility of the model for production planning, we run operations for a planning horizon of a year for a case study. When the primary results of this mathematical programming are compared with the historical records, the model could have resulted in the considerable increase of the total growth margin by effectively reducing inventory cost if a decision maker had employed the model as a decision support system with perfect information for sales demand.

• 한국정보시스템학회지:정보시스템연구
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• 제23권1호
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• pp.185-202
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• 2014

ERP, a typical enterprise application, helps companies to increase their productivity and to support their decision makings. ERP is composed of diverse functions that are optimized under PC environment, whereas the ERP applications on a mobile platform have many constraints such as a small screen, limited resolution, and computing power. Because all the functions of a ERP legacy system are not required for ERP on a mobile device, the core functions of the ERP system should be selected to increase system efficiency. In this study, two main methods were used; interviews and log analyses. The end users using a ERP system were interviewed for their perceptions, and log data analyses were made for the hitting number of specific ERP functions. The differences between the actual usage based on log data and users' cognitive preferences about ERP functions were analysed. Finally, the functional differences between users' perception and actual usage were suggested for some practical implications.

• 스마트미디어저널
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• 제11권11호
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• pp.32-39
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• 2022

AI 서비스를 제공하는 IoT 응용이 늘어나면서 자율적인 학습 및 추론을 지원하는 다양한 하드웨어와 소프트웨어들이 개발되고 있다. 하지만 하드웨어마다 특성 및 제약조건이 상이하여 IoT 응용 개발에 어려움이 가중됨에 따라 통합된 플랫폼의 개발이 요구되고 있다. 본 논문에서는 IoT 기술뿐만 아니라 인공 신경망 및 스파이킹 신경망 기반의 컴포넌트를 오픈 플랫폼과 호환되도록 자동 생성하는 도구를 제안한다. 제안하는 컴포넌트 자동 생성 도구는 IoT 및 AI의 가상 컴포넌트 계층을 통해 다양한 하드웨어의 특성에 맞는 컴포넌트 생성을 용이하게 하고 자동으로 오픈 플랫폼에 적용할 수 있도록 지원한다.

• International Journal of Computer Science & Network Security
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• 제22권3호
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• pp.163-172
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• 2022

The interconnection of an enormous number of devices into the Internet at a massive scale is a consequence of the Internet of Things (IoT). As a result, tasks offloading from these IoT devices to remote cloud data centers become expensive and inefficient as their number and amount of its emitted data increase exponentially. It is also a challenge to optimize IoT device energy consumption while meeting its application time deadline and data delivery constraints. Consequently, Fog Computing was proposed to support efficient IoT tasks processing as it has a feature of lower service delay, being adjacent to IoT nodes. However, cloud task offloading is still performed frequently as Fog computing has less resources compared to remote cloud. Thus, optimized schemes are required to correctly characterize and distribute IoT devices tasks offloading in a hybrid IoT, Fog, and cloud paradigm. In this paper, we present a detailed survey and classification of of recently published research articles that address the energy efficiency of task offloading schemes in IoT-Fog-Cloud paradigm. Moreover, we also developed a taxonomy for the classification of these schemes and provided a comparative study of different schemes: by identifying achieved advantage and disadvantage of each scheme, as well its related drawbacks and limitations. Moreover, we also state open research issues in the development of energy efficient, scalable, optimized task offloading schemes for Fog computing.

• 지역사회간호학회지
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• 제25권4호
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• pp.270-281
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• 2014

Purpose: The purpose of the study was to understand low-income elders' experiences of community-based u-Health services. Methods: Qualitative data were collected from 11 participants. All interviews were recorded and transcribed verbatim. The transcribed data were analyzed using qualitative content analysis. Results: Three themes and eight sub-themes emerged as a result of analysis. The three main themes were 'recovered confidence and health condition,' 'trial and error in change,' and 'hope.'The eight sub-themes were 'the burden and efforts to overcome it in using bio-signal device,' 'ambivalence due to changing lifestyle,' 'increase of care time, decrease of pressure', 'conflict under environmental constraints,' 'difficulty in prioritizing health management,' 'discouragement in handling new devices,' 'desire not to be a burden to their children-gradual fulfillment of learning needs,' and 'long for broadening coverage range of services.' Conclusion: The findings of this study demonstrate that low-income elders among the participants have different needs in using u-Health services. Therefore, health professionals need to give personalized education to deal with their conflicts and requirements, especially emotional and environmental support in order for them to successfully accept the u-Health services for self-care.