• 대한두개안면성형외과학회지
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• 제21권6호
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• pp.345-350
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• 2020

Background: This study evaluated the efficacy of the endoscopic medial orbital wall repair by comparing it with the conventional transcaruncular method. This surgical approach differs from the established endoscopic technique in that we push the mesh inside the orbit rather than placing it over the defect. Methods: We retrospectively reviewed 40 patients with isolated medial orbital blowout fractures who underwent medial orbital wall reconstruction. Twenty-six patients underwent endoscopic repair, and 14 patients underwent external repair. All patients had preoperative computed tomography scans taken to determine the defect size. Pre- and postoperative exophthalmometry, operation time, the existence of diplopia, and pain were evaluated and compared between the two methods. We present a case showing our procedure. Results: The operation time was significantly shorter in the endoscopic group (44.7 minutes vs. 73.9 minutes, p= 0.035). The preoperative defect size, enophthalmos correction rate, and pain did not significantly differ between the two groups. All patients with preoperative diplopia, eyeball movement limitation, or enophthalmos had their symptoms resolved, except for one patient who had preexisting strabismus. Conclusion: This study demonstrates that endoscopic medial orbital wall repair is not inferior to the transcaruncular method. The endoscopic approach seems to reduce the operation time, probably because the dissection process is shorter, and no wound repair is needed. Compared to the previous endoscopic method, our method is not complicated, and is more physiological. Larger scale studies should be performed for validation.

• 한국정보시스템학회지:정보시스템연구
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• 제30권4호
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• pp.43-69
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• 2021

Purpose Although companies occupied the network market take the advantageous position first and can be successful in securing users over a certain size, it is important to satisfy the customers' demand and prevent the outflow of users toward a new alternative SNS. What is more, there are frequent changes in the flow of users toward new SNSs. Despite these dynamic market circumstances, there is a lack of research to explain the switching behaviors of SNS users. Design/methodology/approach The objective of this study is to explain and verify a specified migration theory(Push-Pull-Mooring model) focused on SNS fatigue in the psychological point of view, as well as reviewing previous studies on functional and technical characteristics of SNSs themselves. Moreover, this study tried to highlight factors affecting users actual SNS switch rather than their switching intention. Findings According to the statistical analysis, the most influenced pull factor to switch SNS was the alternative attractiveness. On the other hand, undesired relationship burden, service innovation and important mooring factors to prevent users' SNS switch. This study has a significant contribution to the theory, which analyzed users' actual SNS switch, and examined SNS users' psychological factors(SNS fatigue), reviewing the characteristics of existing services. To secure more users and to keep them, companies providing social network service need to develop differentiated strategies by analyzing psychological characteristics of various users.

• 한국지진공학회논문집
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• 제26권6호
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• pp.255-265
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• 2022

In order to determine fragility curves, the limit state of piers for each damage level is suggested in this paper based on the previous test results in Korea, including our test results. In previous studies, the quantitative measures for damage levels of piers have been represented by curvature ductility, lateral drift ratio, or displacement ductility. These measures are transformed to lateral drift ratios of piers for consistency, and the transformed values are compared and verified with our push-over test results for flexural RC piers with a circular cross-section. The test specimens are categorized concerning the number of lap-splices in the plastic hinge region and whether seismic design codes are satisfied or not. Based on the collected test results in Korea, including ours, the lateral drift ratio for each pier damage level is suggested.

• Asia Marketing Journal
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• 제16권1호
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• pp.229-241
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• 2014

In 1997 the Asian Foreign Currency Crisis hit Korean shores. In its wake, Korean consumers demanded cost-saving solutions which will increase both the use-life and the fuel efficiency their vehicles. Bullsoneshot's effects include increases in gas mileage as well as cleaner cylinders, intakes and exhaust valves, the product was welcomed by an explosive demand from people driving older cars in an adverse economy. The history of Bullsone can be categorized as two major stages. The First stage is lunching era of "Bullone Shot" following competitor brand. The second stage is extension stage of brand and line based on Bullsone's positive brand equity. Mr. Hyun Woo Shin, formal CEO of OXY inc. and also formal vice president of OCI (Oriental Chemical Industries) take charge of New CEO of Bullsone. He energetically push the Bullsone's family brands and got a desirable results. He also setup ambitious goal : reach 100bn KRW in gross sales within 3 years. "Ripping itself free from 30~40 bn KRW sales range in which the company has stagnated in the last 10 years, Bullsone intends to be aggressive enough in marketing to reach 150 bn KRW in sales in 2013, and reach 700 bn KRW by 2018." This is the goal iterated by Bullsone's top executive team.

• Earthquakes and Structures
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• 제25권6호
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• pp.443-454
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• 2023

Steel shear walls are used to strengthen steel and concrete structures. One such system is Partial Attached Steel Shear Walls (PASSW), which are only connected to frame beams. This system offers both structural and architectural advantages. This study first calibrated the numerical model of RC frames with and without PASSW using an experimental sample. The seismic performance of the RC frame was evaluated by 30 non-linear static analyses, which considered stiffness, ductility, lateral strength, and energy dissipation, to investigate the effect of PASSW width and column axial load. Based on numerical results and a curve fitting technique, a lateral stiffness equation was developed for frames equipped with PASSW. The effect of the shear wall location on the concrete frame was evaluated through eight analyses. Nonlinear dynamic analysis was performed to investigate the effect of the shear wall on maximum frame displacement using three earthquake records. The results revealed that if PASSW is designed with appropriate stiffness, it can increase the energy dissipation and ductility of the frame by 2 and 1.2 times, respectively. The stiffness and strength of the frame are greatly influenced by PASSW, while axial force has the most significant negative impact on energy dissipation. Furthermore, the location of PASSW does not affect the frame's behavior, and it is possible to have large openings in the frame bay.

• 한국지진공학회논문집
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• 제6권3호
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• pp.1-10
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• 2002

비록 제한된 범위내에서나마 일련의 유한요소해석을 통하여 비보강 조적조 벽체의 면내방향 내진성능을 조사하였다. 이를 위하여 비보강 조적벽체는 연속체로 가정하여 등방성 평면응력요소로 취급하였으며, 비보강 조적조의 균열거동을 위하여 균열특성이 요소내에 분포하는 것으로 가정하는 분포균열모델을 사용하였다. 모두 70가지 서로 다른 경우의 비보강 조적벽체 모델을 해석하였는데, 축력비, 형상비 및 유효단면적비 등의 변수를 고려하였다. 해석결과 이들 변수가 비보강 조적벽체의 극한강도에 지대한 영향을 미치며 상호 작용하는 것으로 확인되었다. 비보강 조적벽체의 여러 가지 취성적 요인과 복합적인 파괴형태의 가능성을 감안하여 현재 우리 나라 규준에서 사용하고 있는 반응수정계수의 크기를 재고하여야 함이 지적되었다.

• Advances in Computational Design
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• 제3권3호
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• pp.233-267
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• 2018

Conventional seismic design of concentrically braced frame (CBF) structures suggests that the gusset plate connecting a steel brace to beams and/or columns should be designed as non-dissipative in earthquakes, while the steel brace members should be designed as dissipative elements. These design intentions lead to thicker and larger gusset plates in design on one hand and a potentially under-rated contribution of gusset plates in design, on the other hand. In contrast, research has shown that compact and thinner gusset plates designed in accordance with the elliptical clearance method rather than the conventional standard linear clearance method can enhance system ductility and energy dissipation capacity in concentrically braced steel frames. In order to assess the two design methods, six cyclic push-over tests on full scale models of concentric braced steel frame structures were conducted. Furthermore, a 3D finite element (FE) shell model, incorporating state-of-the-art tools and techniques in numerical simulation, was developed that successfully replicates the response of gusset plate and bracing members under fully reversed cyclic axial loading. Direct measurements from strain gauges applied to the physical models were used primarily to validate FE models, while comparisons of hysteresis load-displacement loops from physical and numerical models were used to highlight the overall performance of the FE models. The study shows the two design methods attain structural response as per the design intentions; however, the elliptical clearance method has a superiority over the standard linear method as a fact of improving detailing of the gusset plates, enhancing resisting capacity and improving deformability of a CBF structure. Considerations were proposed for improvement of guidelines for detailing gusset plates and bracing members in CBF structures.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 1998년도 Proceedings of International Symposium on Remote Sensing
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• pp.313-318
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• 1998

Electro-Optical Camera(EOC) is the main payload of Korea Multi-Purpose SATellite(KOMPSAT) with the mission of cartography to build up a digital map of Korean territory including Digital Terrain Elevation Map(DTEM). This instrument which comprises EOC Sensor Assembly and EOC Electronics Assembly produces the panchromatic images of 6.6 m GSD with a swath wider than 17 km by push-broom scanning and spacecraft body pointing in a visible range of wavelength, 510 ~ 730 nm. The high resolution panchromatic image is to be collected for 2 minutes during 98 minutes of orbit cycle covering about 800 km along ground track, over the mission lifetime of 3 years with the functions of programmable rain/offset and on-board image data storage. The image of 8 bit digitization, which is collected by a full reflective type F8.3 triplet without obscuration, is to be transmitted to Ground Station at a rate less than 25 Mbps. EOC was elaborated to have the performance which meets or surpasses its requirements of design phase. The spectral response the modulation transfer function, and the uniformity of all the 2592 pixel of CCD of EOC are illustrated as they were measured for the convenience of end-user. The spectral response was measured with respect to each gain setup of EOC and this is expected to give the capability of generating more accurate panchromatic image to the EOC data users. The modulation transfer function of EOC was measured as greater than 16% at Nyquist frequency over the entire field of view which exceeds its requirement of larger than 10%, The uniformity that shows the relative response of each pixel of CCD was measured at every pixel of the Focal Plane Array of EOC and is illustrated for the data processing.

• 대한원격탐사학회지
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• 제18권1호
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• pp.53-59
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• 2002

The MSC is a payload on the KOMPSAT-2 satellite to perform the earth remote sensing. The instrument images the earth using a push-broom motion with a swath width of 15 km and a GSD(Ground Sample Distance) of 1 m over the entire FOV(Field Of View) at altitude 685 km. The instrument is designed to haute an on-orbit operation duty cycle of 20% over the mission lifetime of 3 years with the functions of programmable gain/offset and on-board image data compression/storage. The MSC instrument has one channel for panchromatic imaging and four channel for multi-spectral imaging covering the spectral range from 450nm to 900nm using TDI(Time Belayed Integration) CCD(Charge Coupled Device) FPA(Focal Plane Assembly). The MSC hardware consists of three subsystem, EOS(Electro Optic camera Subsystem), PMU(Payload Management Unit) and PDTS(Payload Data Transmission Subsystem) and each subsystems are currently under development and will be integrated and verified through functional and space environment tests. Final verified MSC will be delivered to spacecraft bus for AIT(Assembly, Integration and Test) and then COMSAT-2 satellite will be launched after verification process through IST(Integrated Satellite Test). In this paper, the introduction of MSC, the configuration of MSC electronics including electrical interlace and design of CEU(Camera Electronic Unit) in EOS are described. MSC Operation parameters induced from the operation concept are discussed and analyzed to find the influence of system for on-orbit operation in future.

• 기록학연구
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• 제4호
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• pp.93-130
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• 2001

Chosen General Government initiated the activities of collecting and managing the archives from Chosen Dynasty because of necessity to push positively for its colonial policies. Particularly, such efforts of the regime resulted eventually in boosting their understanding on the Korea cultures, as well as contributed to their reigning Korea to an extent. Some aspects that reflect it are as follows. In 1910 Chosen General Government took over, and began to arrange and classify huge volumes of archives that were held by the royal family. During this period, they collected and arranged literatures that they took over from the earlier Korean government. In 1913, Chosen General Government increased enormously the varieties and volumes of the archives that they intended to collect. They started with collecting archives limited to those literatures that had existed in the civil sector before 1894. It can be noticed that just in 1913 Chosen General Government revealed their intention to collect and classify both royal archives and civil archives. With the work of collecting, classification and annotating archives, Chosen General Government commenced the compilation of Chosensa (Korean History). These efforts aimed at cultural assimilation and educating of Korean people, and in this process, the importance of Chosen Dynasty's archives was reconfirmed. One of the representative cases was a change of terminology. With the compilation efforts into full swing since 1915, Chosen General Government repeatedly started to use the term 'Saryo' (historical records) in connection with Chosen's literatures and archives. The term 'Saryo' previously had been used in Japanese literatures, and it is deemed that it was used as a term generally referring to archives of Chosen Dynasty from that time. This signifies that Chosen General Government began to involve their historical point of view in approaching to the archives of Chosen. As they broadened their understanding on Korea through the annotation of old literatures and compilation of Chosen History, they seriously set on the work of assimilating Korean people culturally aiming at gripping its reign on Korea. Archives of Chosen likewise were very crucial basic data for understanding Korea and its people, and Chosen General Government is deemed to have utilized the archives as a means to reign and assimilate Korean people.