• International Journal of Aeronautical and Space Sciences
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• v.10 no.2
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• pp.148-160
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• 2009

By the development of recent technology, a new variant of rotorcrafts having four rotors start drawing attention from aerial-robotics engineers more than before. Its potential spans from just being control device test bed to performing difficult task such as carrying surveillance device to unreachable places. In this regards, modeling a quad-rotor is significant in analyzing its dynamic behavior and in synthesizing control system for such a vehicle. This paper summarizes the modeling of a mini quad-rotor aerial vehicle. A first principle approach is considered for deriving the model based on Euler-Newton equations of motion. The result of the modeling is a simulation platform that is expected to acceptably predict the dynamic behavior of the quad-rotor in various flight conditions. Linear models associated with different flight condition can be extracted for the purpose of control synthesis.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.1
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• pp.33-39
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• 2007

One of the most important processes is the face milling in processing task. It makes the smooth surface of processed goods. In processing stage, the formation of burr is inevitable. The formed burr decreases a detailed drawing and effects the safety of workers. So, it causes a deburring process for removing and a bottle-neck condition. Therefore, the study which can minimize the generation of burr is needed. In this paper, complex feature, such as line, arc, circle, spline is studied more reality than any other papers. And also, the algorithm which can predict the path of generated burr is established. Moreover, the finality goal is that the system which can produce tool-path minimized has to be developed.

• Archives of Plastic Surgery
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• v.40 no.6
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• pp.783-786
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• 2013

For years, the gold standard in facial rejuvenation has been the face lift. However, exploring new, less complex procedures for achieving the same goal is currently drawing interest. Rejuvenation of the perioral area is a difficult task for plastic surgeons because of the minimal effect that face lift procedures have over this region and the lack of published material on the subject. In this article, the descended mouth corner anguloplasty technique is presented. It is a 20-minutes lift technique that can correct this typical feature of the ageing mouth. The authors have treated 71 patients using the technique with consistently good results, with just one requiring revision. They conclude that this procedure by itself and in combination with other small operations or even a full face lift can rejuvenate the ageing face.

• Knowledge Management Research
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• v.20 no.4
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• pp.149-168
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• 2019

In the era of the Fourth Industrial Revolution, digital transformation is emerging in the education and learning fields. As the use of the mobile Internet and mobile devices has become a daily life, mobile learning that supports a variety of learning in a mobile environment is drawing attention. Mobile learning applications (apps) are expected to expand their use by providing a convenient learning environment anytime, anywhere. This study investigates the use of mobile learning apps in English education, which is one of the most popular learning areas, and empirically examines the factors that influence the continuous use of mobile learning apps. In particular, it analyzes the differences between Chinese and Korean users. The results of this study provide theoretical and practical implications to promote the development of mobile apps suitable for mobile learning environments and the sustainable user growth in mobile learning.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2001.10a
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• pp.219-226
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• 2001

In general, engineers have to consider a variety of factors in design of a structure. For this reason, it was difficult to make a design program up to now. But the rapid development of hardware and software turns it into a possibile one with considering complex factors and designing simple structures. When we use the design program including structural analysis, we can save time and cost to make calculations; report and drawing. In addition, the design program was developed to reduce the man made errors. Therefore, in this study, we try to develope the design program of the superstructure of P.S.C girder bridge and abutment. This program will provide engineers with time that they can spend on a creative and efficiency task for development of design.

• Journal of the Korea Society of Computer and Information
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• v.23 no.4
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• pp.139-145
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• 2018

In this paper, we propose the methodology and system to show weather information to spatial system. When using the spatial information system, it is easy and convenient to show information such as target location, mission contents, enemy threats and so on. However, drawing 1-dimensional weather information on 3-dimensional space in spatial information system is hard task. To fuse data, we need to add a spatial layer including weather information to spatial layers and perform space modeling for showing weather information as spatial data in a virtual space. The virtual space is shown by receiving meteorological data and then changing in real time through weather database linkage.

• Journal of the military operations research society of Korea
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• v.25 no.1
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• pp.87-106
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• 1999

There are many technical datum in related with design, test & evaluation and logistic support which will be exchanged between geographically isolated units and heterogeneous hardwares & softwares in developing and operating the weapon systems. The paper proposes the conceptual database schema to establish configuration management information systems in which these datum can be automatically interchanged, tracked, audited and status-accounted without errors under the various environments. The paper investigates how to identify and classify the data in accordance with document identification, task analysis, system development, logistic support, system test & evaluation and data management. Furthermore, the investigation includes drawing the subject areas and modeling the conceptual database schema to explain the relationships between these datum. Thus, the paper results in the conceptual framework and data models of configuration management information systems, while additional customization efforts be required in applying the models to a specific weapon systems R&D.

• Wind and Structures
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• v.16 no.6
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• pp.617-627
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• 2013

In wind load calculations based on pressure measurements, the concept of 'tributary area' is usually used. The literature has less guidance for a systematic computational methodology for calculating tributary areas, in general, and for scattered pressure taps, in particular. To the best of the author's knowledge, there is no generic mathematical equation that helps calculate the tributary areas for irregular pressure taps. Traditionally, the drawing of tributary boundaries for scattered and intensively distributed taps may not be feasible (a time and resource consuming task). To alleviate this problem, this paper presents a proposed numerical approach for tributary area calculations on rectangular surfaces. The approach makes use of the available coordinates of the pressure taps and the dimensions of the surface. The proposed technique is illustrated by two application examples: first, quasi-regularly distributed pressure taps, and second, taps that have scattered distribution on a rectangular surface. The accuracy and the efficacy of the approach are assessed, and a comparison with a traditional method is presented.

• Asia Marketing Journal
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• v.17 no.2
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• pp.63-71
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• 2015

In this research, we explore whether mere exposure to external cues with vertical progress (e.g., moving upward or moving downward) can influence individuals' persistence to complete focal tasks. Drawing on the theory of embodied cognition, we propose that, a moving-upward (vs. downward) cue activates the abstract concept of difficulty, which is associated with the physical experience of climbing uphill (vs. downhill). Due to this association between moving uphill and difficulty, merely exposing individuals to the moving-upward cue can induce greater feeling of difficulty and this greater difficulty, in turn, reduce individuals' persistence, compared to exposing individuals to the moving-downward cue. Across three studies, we find supporting evidence for the effect of the external cues with vertical progress on individuals' performance both in physical tasks and in a cognitive task.

• Journal of Korea Technology Innovation Society
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• v.10 no.4
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• pp.755-788
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• 2007

This study investigates the effects of individual and group level factors on the use of GSS (Group Support System) and task performance from GSS use. GSS facilitates the group work, so that GSS adoption is not necessarily influenced only by individual perceptions on information systems. Adaptive Structuration Theory (AST) in our study to explain the adoption and success from GSS use. AST contends that the success of IS is not necessarily the technical fit between tasks and technology, instead the political outcome among user socializations. We have the following two research inquires: Are the IS use and performance maximized when information technologies are provided properly?; and, Does TTF always influence positively on IS use (or performance)? To research these issues, we investigate the influence of TTF (Task-Technology Fit) on use and performance of GSS, which is introduced to foster collaboration among organizational members. Drawing insights from the AST, we examine if COA (Consensus on Appropriation) among group members and FOA (Faithfulness of Appropriation) between those who use technology and who design it show any moderating effect. A questionnaire survey was conducted on firms using the GSS for one month from June 2 to June 27 2005 and a sample of 303 responses was used for a statistical analysis. The result demonstrates that TTF exerts a positive influence on use and performance of GSS. We find that the stronger the COA, the greater the effect of W on use of GSS and performance. FOA likewise has a positive effect on both use of GSS and performance. The TTF model has been widely applied to studies on individual performance of information system, whereas the AST theory specifically explains members' adaptation process to information system. By integrating the AST theory with the TTF model, the study contributes to heightening our understanding on if and how individual performance varies with the use of GSS.