• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권12호
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• pp.5015-5027
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• 2015

Transceiver optimization in multiple input multiple output (MIMO) cognitive systems is studied in this paper. The joint transceiver beamformer design is introduced to minimize the transmit power at secondary base station (SBS) while simultaneously controlling the interference to primary users (PUs) and satisfying the secondary users (SUs) signal-to-interference-plus-noise ratio (SINR) based on the convex optimization method. Due to the limited cooperation between SBS and PUs, the channel state information (CSI) usually cannot be obtained perfectly at the SBS in cognitive system. In this study, both perfect and imperfect CSI scenarios are considered in the beamformer design, and the proposed method is robust to CSI error. Numerical results validate the effectiveness of the proposed algorithm.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집 특별세미나,특별/일반세션
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• pp.183-188
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• 2009

The High speed electrical multiple train having a distributed electrical motor system has just been developing to aim the experimental maximum speed at 400km/h since August, 2007. This project comes in stage of basic design and so, it needs to take some review and analysis the characteristics of suspensions on the view of basic design. The vehicle model for dynamic analysis is made from the concept design model that used for the preliminary design review with Vampire program and it is modeled with three linear secondary dampers and two shear springs separated from the bush elements in previous model. The optimization technique is applied to search the proper range of linear characteristics for the suspension elements to satisfy the stability performance at speed 130m/s (about 460km/h). The results shows there are some optimum points according to the variation of primary and secondary suspension characteristics and it would be useful to make a decision to select the proper suspension elements in the precision design that will be done by the manufacturing company.

• 한국공작기계학회논문집
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• 제16권2호
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• pp.70-77
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• 2007

The application of focused ion beam(FIB) technology has been broadened in the fabrication of nanoscale regime. The extended application of FIB is dependent on complicated reciprocal relation of operating parameters. It is necessary for successful and efficient modifications on the surface of silicon substrate. The primary effect by Gaussian beam intensity is significantly shown from various aperture size, accelerating voltage, and beam current. Also, the secondary effect of other process factors - dwell time, pixel interval, scan mode, and pattern size has affected to etching results. For the process analysis, influence of the secondary factors on FIB micromilling process is examined with respect to sputtering depth during the milling process in silicon material. The results are analyzed by the ratio of signal to noise obtained using design of experiment in each parameter.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 추계학술대회 논문집 학회본부
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• pp.401-404
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• 1991

In this paper, the controllers for the motion of the 2-joint manipulator design two stages: (1) a primary controller that under ideal conditions makes the end-effector track the desired trajectory: (2) a secondary controller that compensates for undesirable deviations of the motion from the disired trajectory caused by external and/or internal disturbances. The secondary contoller is applied to PID control algorithm. and the controllers is actually designed using IBM-PC/AT and 8096 single chip microprocessor.

• Journal of the Optical Society of Korea
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• 제20권1호
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• pp.94-100
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• 2016

A novel optical design for high resolution, large field of view (FOV) and multispectral remote sensing is presented. An f/7.3 Korsch and two f/17.9 Cook three-mirror optical systems are integrated by sharing the primary and secondary mirrors, bias of the FOV, decentering of the apertures and reasonable structure arrangement. The aperture stop of the Korsch system is located on the primary mirror, while those of the Cook systems are on the exit pupils. High resolution image with spectral coverage from visible to near-infrared (NIR) can be acquired through the Korsch system with a focal length of 14 m, while wide-field imaging is accomplished by the two Cook systems whose focal lengths are both 13.24 m. The full FOV is 4°×0.13°, a coverage width of 34.9 km at the altitude of 500 km can then be acquired by push-broom imaging. To facilitate controlling the stray light, the intermediate images and the real exit pupils are spatially available. After optimization, a near diffraction-limited performance and a compact optical package are achieved. The sharing of the on-axis primary and secondary mirrors reduces the cost of fabrication, test, and manufacture effectively. Besides, the two tertiary mirrors of the Cook systems possess the same parameters, further cutting down the cost.

• Journal of Magnetics
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• 제21권3호
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• pp.374-378
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• 2016

The transformer used in an inverter type arc welding machine is designed to use high frequency in order to reduce its size and cost. Also, selecting core materials that fit frequency is important because core loss increases in a high frequency band. An inrush current can occur in the primary coil of transformer during arc welding and this inrush current can cause IGBT, the switching element, to burn out. The transformer design was carried out in $A_P$ method and amorphous core was used to reduce the size of transformer. In addition, sheet coil was used for primary winding and secondary winding coil considering the skin effect. This paper designed the transformer core with an air gap to prevent IGBT burnout due to the inrush current during welding and proposed the optimum air gap length.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제31권3호
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• pp.267-272
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• 2009

Bone grafting the alveolar cleft allows for stability and continuity of the dental arch, provides bone for eruption of permanent teeth or placement of dental implants, and gives support to the lateral ala of the nose. Closure of residual oronasal fistula can occur simultaneously. Repair of alveolar clefts can occur at a variety of stages defined as primary, early secondary, secondary, and late. Most centers perform this surgery as secondary bone grafting. Autogenous bone provides osteogenesis, osteoinduction and conduction and is recommended for grafting to the cleft alveolus and several donor sites are available. The surgeon should select the best flap design considering the amount of mucosa available, blood supply and tension-free closure, and the extent of the oronasal communication. The authors provide a comprehensive understanding of alveolar clefts and their repair by reviewing the historical perspective, objectives for treatment, timing, source of graft, presurgical orthodontics, surgical techniques, postoperative care, and complications.

• 한국정보통신학회논문지
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• 제18권12호
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• pp.2891-2898
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• 2014

항공기용 Integrated Modular Avionics (IMA) 시스템의 경우 모듈 단위 이중화를 통하여 결함 감내 기능을 구현할 수 있다. 하지만, 이중화 구성 시 반드시 요구되는 소프트웨어 동기화는 하드웨어의 비동기적인 특성으로 인해 실제 구현 시 높은 복잡도를 야기한다. 이러한 문제점을 해결하기 위하여 현재 IMA시스템에서의 PALS(Physically Asynchronous Logically Synchronous) 디자인 패턴이 제안되었으나 실제 시스템 적용시 각 시스템의 특성에 따른 변화가 불가피하다. 본 연구는 PALS 디자인 패턴을 참조하여 Primary /Secondary 이중화를 이용하는 IMA 시스템에서의 입력데이터 동기화 설계방안을 연구하였다. 제안된 방식은 Rate Monotonic Scheduling (RMS) 방식을 고려하여 프레임 윈도우에 동기된 기법을 제안하고 있으며 시스템에 알맞은 동기화 시간을 분석하고 제안한다. 마지막으로 실험 및 분석을 통하여 제안된 방법의 타당성을 검증하였다.

• Perspectives in Nursing Science
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• 제12권1호
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• pp.60-70
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• 2015

Purpose: The purpose of this study was to identify the factors influencing medication adherence in hemodialysis patients among primary medical care and secondary medical care. Methods: A cross-sectional survey design was utilized. Data were collected using questionnaires from 280 hemodialysis patients who had taken prescribed medication regularly as a result of chronic renal failure at primary and secondary medical care in Korea. Data were analyzed using t-test, ANOVA, Pearson correlation coefficients, and multiple regression. Results: There were statistically significant differences in medication adherence according to living area (p=.002), health condition (p<.001), amount of medication (p=.004), inconvenience for taking medication (p<.001), and depression level (p=.001). The mean of medication adherence was 3.72 points. Medication adherence was explained by perceived barrier related to medication taking (${\beta}=.338$), attitude (${\beta}=.250$), and depression (${\beta}=.132$). Conclusion: This study strongly recommended that nursing intervention program to improve medication adherence should be developed and a match control study in improvement of medication adherence for hemodialysis patients needs to be done.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2010년도 제35회 추계학술대회논문집
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• pp.130-134
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• 2010

1차 유동과 2차 유동이 일정 압력으로 혼합하는 초음속 이젝터의 설계 인자들에 대한 연구를 수행하였다. 선정된 이젝터의 설계 인자는 1)질량유량비 2)면적비 3)1차유동의 마하수 이다. 이를 위해 이젝터 유동을 1차원으로 가정하였으며 손실이 있는 경우와 이상적인 경우에 대해 이적테의 성능을 압력비의 항으로 모사하였고 요구되는 이젝터의 수축률을 계산하였다. 또, 이젝터의 최적 설계를 위해 손실을 고려한 경우와 이상적인 경우를 비교하여 작동조건에 필요한 설계점을 도출하였다.