• Journal of Satellite, Information and Communications
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• v.9 no.3
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• pp.86-90
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• 2014

A DC-DC Converter operates in CCM(Continuous Coundcution Mode), DCM(Discontinuous Conduction Mode), CRM(Critical Conduction Mode). The CRM is boundary between CCM and DCM. If a DC-DC converter is designed to operate in CRM, its inductor volume can decrease and power loss which caused by switch and diode can decrease. In this paper, the DC-DC converter which operates in CRM is applied to a solar array regulator(SAR) for the satellite. The switching frequency of the CRM boost SAR changes according to input and output condition. The switching frequency limit logic is applied to limit the maximum switching frequency. Meanwhile, the small signal transfer function of the CRM boost SAR is simple, so the controller design is also simple. In this paper, the small signal transfer function from control reference to solar array voltage is induced. And the voltage controller is designed based on the small signal transfer function. Finally, the CRM boost SAR is verified by simulation.

• The Journal of the Acoustical Society of Korea
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• v.41 no.2
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• pp.131-142
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• 2022

In order to examine the possibility of horizontal simulations of acoustic waves on the environments of big water depth variations, this study introduces a 3-dimensional model based on the pababolic equation. The model gives approximated solutions by separating the cross- and non cross-terms in the equation. Assuming artificial bathymetry (25 km × 4 km) with a source frequency 75 Hz, the simulations give clear horizontal refractions on the transmission loss distributions. The degree of refractions shows non-linear increase along the propagating range and proportional increase with water depth along the cross range. Another simulations with the real bathymetry (25 km × 8 km) also give clear horizontal refractions. The horizontal distributions present little difference with the depth resolution variations of the same data source because the model gives interpolations over the depth data before simulations. Meanwhile, the horizontal distributions show big difference with those of different data sources.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.36 no.1
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• pp.78-95
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• 2023

목적 : 마이크로니들 패치는 피부장벽의 주요 구성성분인 각질층을 관통할 수 있어 일반적인 경피를 통한 약물 전달 수단보다 더 효율적으로 약물을 전달할 수 있다는 장점이 있어 다양한 분야에서 응용되고 있다. 본 임상연구는 아토피피부염 환자의 피부 건조 증상에 대하여 용해성 히알루론산 마이크로니들 패치와 외용제를 병행하여 용해성 마이크로니들 패치의 유효성과 안전성을 평가하였다. 방법 : 본 연구는 단일 기관, 연구자 주도, 평가자 눈가림, 인체 분할 연구로 설계된 무작위 배정 임상시험으로, 피부건조 증상이 있는 아토피피부염 환자 20명을 대상으로 임상연구를 수행하였다. 한 명의 피험자에서 2곳의 시험 병변을 선택한 후, 무작위 배정으로 각각 시험 병변과 대조 병변을 결정하여 2주 동안 매일 양측 병변에 모두 아로마 크림을 도포한 다음, 시험 병변에만 용해성 히알루론산 마이크로니들 패치를 추가로 부착하였다. 결과 : 1차 유효성 평가지표인 local scoring atopic dermatitis(L-SCORAD) index는 치료 후에 시험 병변이 대조 병변보다 유의성 있게 호전되었다. 2차 유효성 평가지표 중 피부 건조감 VAS와 피부 수분 함유량도 시험 병변이 대조 병변보다 유의성 있는 개선을 보였다. Investigator's Global Assessment scale, 소양감 VAS, 경피수분손실량에 있어서는 시험 병변과 대조 병변 모두 치료 후에 유의성 있게 호전되었으나, 두 병변 간의 차이에는 유의성이 없었다. 이상 반응은 나타나지 않았으므로 안전성도 확인되었다. 결론 : 용해성 히알루론산 마이크로니들 패치와 외용제 병행치료는 외용제만 사용하였을 때보다 L-SCORAD index 및 피부 건조감 VAS, 피부 수분 함유량에 있어서 아토피피부염의 증상을 유의성 있게 개선시켰다.

• Journal of Internet Computing and Services
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• v.10 no.4
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• pp.199-211
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• 2009

Recent advancements in wireless networks have enabled support for mobile applications to transfer data over heterogeneous wireless paths in parallel using data striping technique [2]. Traditionally, high performance data transfer requires tuning of multiple TCP sockets, at sender's end, based on bandwidth delay product (BDP). Moreover, traditional techniques like Automatic TCP Buffer Tuning (ATBT), which balance memory and fulfill network demand, is designed for wired infrastructure assuming single flow on a single socket. Hence, in this paper we propose a buffer tuning technique at senders end designed to ensure high performance data transfer by striping data at transport layer across heterogeneous wireless paths. Our mechanism has the capability to become a resource management system for transport layer connections running on multi-homed mobile host supporting features for wireless link i.e. mobility, bandwidth fluctuations, link level losses. We show that our proposed mechanism performs better than ATBT, in efficiently utilizing memory and achieving aggregate throughput.