• 정보처리학회논문지:컴퓨터 및 통신 시스템
• /
• 제7권2호
• /
• pp.33-40
• /
• 2018

네트워크 대역폭이 큰 환경에서는 대역폭 활용률을 극대화함으로써 전송효율성을 높이는 것이 매우 중요한 이슈이다. 종단간 전송효율성은 네트워크, 데이터 전송 노드 그리고 기관 내 네트워크 보안정책 등 구성요소에 따라 크게 영향을 받는다. Science DMZ는 이러한 복합적인 구성요소들의 최적의 해결 방안을 통해 전송성능을 극대화하기 위한 혁신적인 네트워크 구조이다. 이 중에서 데이터 전송 노드는 스토리지, 네트워크 인터페이스, 운영체제, 전송응용 도구에 따라 전송성능에 크게 영향을 주는 핵심 요소이다. 하지만 고속네트워크 환경에서는 데이터 전송 노드를 구성하는 요소들의 적절한 튜닝이 수행되어야 높은 전송효율성을 제공할 수 있다. 본 논문에서는 100Gbps 데이터 전송 노드의 튜닝 요소를 통한 전송성능 향상 방안에 대해 제안한다. 성능측정결과 점보프레임, CPU governor 튜닝을 통해 100Gbps 네트워크 환경에서 전송효율성을 크게 개선할 수 있음을 확인하였다. Iperf를 통한 네트워크 성능테스트 결과 default에 비해 300%의 성능향상을 보였으며 NVMe SSD의 경우 하드디스크와 비교해 140%의 성능개선을 확인하였다.

• Biomolecules & Therapeutics
• /
• 제28권3호
• /
• pp.272-281
• /
• 2020

Environmental agents, including viral and bacterial infectious agents, are involved in the alteration of physicochemical and biological parameters in the nasal epithelium. Hyaluronan (HA) has an important role in the regulation of tissue healing properties. High molecular weight HA (HMW-HA) shows greater anti-inflammatory responses than medium molecular weight HA (MMW-HA) and low molecular weight HA (LMW-HA). We investigated the effect of HMW-HA, MMW-HA and LMW-HA on the regulation of physicochemical and biological parameters in an "in vitro" model that might mimic viral infections of the nasal epithelium. Human nasal epithelial cell line RPMI2650 was stimulated with double-stranded RNA (dsRNA) Poly(I:C) for 5 days in air-liquid-interface (ALI) culture (3D model of airway tissue). dsRNA Poly(I:C) treatment significantly decreased transepithelial electrical resistance (TEER) in the stratified nasal epithelium of RPMI2650 and increased pH values, rheological parameters (elastic G' and viscous G''), and Muc5AC and Muc5B production in the apical wash of ALI culture of RPMI2650 in comparison to untreated cells. RPMI2650 treated with dsRNA Poly(I:C) in the presence of HMW-HA showed lower pH values, Muc5AC and Muc5B production, and rheological parameters, as well as increased TEER values in ALI culture, compared to cells treated with Poly(I:C) alone or pretreated with LMW-HA and MMW-HA. Our 3D "in vitro" model of epithelium suggests that HMW-HA might be a coadjuvant in the pharmacological treatment of viral infections, allowing for the control of some physicochemical and biological properties affecting the epithelial barrier of the nose during infection.

• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 2008년도 International Symposium on Remote Sensing
• /
• pp.220-223
• /
• 2008

A camera system for the satellite application performs the mission of observation by measuring radiated light energy from the target on the earth. As a development stage of the system, the signal level analysis by estimating the number of electron collected in a pixel of an applied CCD is a basic tool for the performance analysis like SNR as well as the data path design of focal plane electronic. In this paper, two methods are presented for the calculation of the number of electrons for signal level analysis. One method is a quantitative assessment based on the CCD characteristics and design parameters of optical module of the system itself in which optical module works for concentrating the light energy onto the focal plane where CCD is located to convert light energy into electrical signal. The other method compares the design\ parameters of the system such as quantum efficiency, focal length and the aperture size of the optics in comparison with existing camera system in orbit. By this way, relative count of electrons to the existing camera system is estimated. The number of electrons, as signal level of the camera system, calculated by described methods is used to design input circuits of AD converter for interfacing the image signal coming from the CCD module in the focal plane electronics. This number is also used for the analysis of the signal level of the CCD output which is critical parameter to design data path between CCD and A/D converter. The FPE(Focal Plane Electronics) designer should decide whether the dividing-circuit is necessary or not between them from the analysis. If it is necessary, the optimized dividing factor of the level should be implemented. This paper describes the analysis of the electron count of a camera system for a satellite application and then of the signal level for the interface design between CCD and A/D converter using two methods. One is a quantitative assessment based on the design parameters of the camera system, the other method compares the design parameters in comparison with those of the existing camera system in orbit for relative counting of the electrons and the signal level estimation. Chapter 2 describes the radiometry of the camera system of a satellite application to show equations for electron counting, Chapter 3 describes a camera system briefly to explain the data flow of imagery information from CCD and Chapter 4 explains the two methods for the analysis of the number of electrons and the signal level. Then conclusion is made in chapter 5.

• 한국통신학회논문지
• /
• 제28권3C호
• /
• pp.307-314
• /
• 2003

일반적으로 화자와 같이 중요하게 인식되는 객체를 시퀸스 전체에서 높은 우선순위를 부여한다. 그러나 다중 객체 동영상 부호화에서 각 객체의 중요도는 시퀸스 전체에서 일관적이지 않고 프레임마다 변화되므로 시변적으로 중요도를 변화시킬 필요가 있다. 따라서 본 논문에서는 독립적 율제어 알고리즘과 정적 파라미터들인 객체 중요도 또는 우선 순위와 목표 PSNR, 가중치 왜곡에 따라 각 객체에 QP를 할당하는 포괄적 율제어 알고리즘을 설명하고 정적 파라미터 중 우선 순위는 카메라 인터페이스를 통해 인간의 시각적 관심도 또는 중요도에 따라 동적 파라미터로 적용하며 목표 PSNR 및 가중치 왜곡은 객체의 크기, 움직임, 왜곡의 세 변수를 기준으로 비율적으로 나타내어 가중치 왜곡 제어와 우선 순위 기반 제어 알고리즘에 적용하여 비트율 분배의 효율을 높이고 있다. 결과로서 중요도가 적은 객체에 대해서는 매우 적은 비트를 할당받게 하며 시각적 중요도가 높은 객체에 대해서는 많은 비트를 할당받게 한다. 또한 화질이 적정 수준으로 안정되는 안정화 시간도 15 프레임 이내로 줄어드는 효과를 보였다 PSNR의 측면에서도 다른 기법에 비해 평균레벨에서 2㏈ 이상 높아지는 결과를 얻어서 인간과 결합한 내용기반 부호기가 다중객체 통영상 부호기에 효과적으로 사용될 수 있음을 제시하였다.

• 한국시뮬레이션학회논문지
• /
• 제26권4호
• /
• pp.51-61
• /
• 2017

최근 빅 데이터가 증가하는 추세에 따라 이를 분석 및 처리하고 활용하는 방안에 대한 관심도 증대되고 있다. 이러한 빅 데이터를 저장, 관리하기 위한 대표적인 플랫폼으로 분산 컴퓨팅 프레임워크인 맵리듀스와 분산 파일 시스템인 HDFS로 구성된 하둡 플랫폼이 있다. 하둡은 일반적으로 수백 수천 대 이상의 클러스터로 구축되는데, 이 때 실제 클러스터 구성이나 파라미터에 따라 하둡 플랫폼이 가지는 효과도를 분석하는 것이 중요하다. 하지만 수천 대 이상의 클러스터 구축하여 이를 분석하는 것이 실질적으로 어렵기 때문에 모델링 및 시뮬레이션 기법을 통해 분석하는 것이 필요하다. 본 논문은 계층적이고 모듈러한 모델링이 가능한 DEVS 형식론을 기반으로 하둡 시뮬레이션 환경을 제안한다. 제안하는 시뮬레이션 환경은 하둡 실행 결과를 이용한 입력 모델 설계를 통해 어플리케이션의 특성을 잘 반영할 수 있으며, 파라미터/알고리즘/모델들을 다양하게 변경하여 실험할 수 있는 재겨냥성 환경을 제공한다. 또한 사용자 편의성의 극대화를 위해 사용자 인터페이스, 실시간 모델 뷰어, 입력 시나리오 편집기를 제공한다. 본 논문에서는 어플리케이션 실행 결과와의 비교를 통해 하둡 시뮬레이터를 검증하고, 다양한 파라미터에 대한 실험을 진행한다.

• 한국IT서비스학회지
• /
• 제14권2호
• /
• pp.289-314
• /
• 2015

Recently, Most of the companies and government offices are under consideration about the adoption of cloud office service to actualize the smart work policies. Comparing with traditional office software, a cloud office service have the advantage of the method of payment and coming over the physical limitations. Many cloud office service users tend to adopt an official evaluated the service without doubt. However after deciding to adopt cloud office service, many users are faced with a variety of problems and difficulties practically. In this study, researchers carried out interview about those problems and difficulties after adopting a cloud office service. Consequently, there are several problems and difficulties such as compatibility, document security, document lost and maladjusted to the new graphic user interface between traditional office software and a cloud office service. A cloud office service have still several advantages not only a competitive price but also ubiquitous attributes. Thus, researchers need to study about what kinds of reason variables can solve those problems and difficulties. In existing research, DeLone & McLean have suggested information system success model. They use three independent variables which are system quality, information quality, service quality. Parameters are user satisfaction, intention to use and use. Lastly, dependent variables are net benefits. However in this study, we need to change the scope of measurement. In other words, we have to replace parameters with dependent variables. Simply, user satisfaction, intention to use and use is going to be dependent variables. There are several reasons why we need changing variables. First, we aim at giving a some suggestions to a cloud service providers which independent variables do not work to satisfy for the users. Second, we need to find out how to maximize cloud office service user's satisfaction and intention to use. Third, we should firstly know that relationship between independent variables and dependent variables. Finally, those research results give for the cloud office service provider to solve the cloud office service adopting problems and difficulties.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2005년도 춘계학술대회논문집
• /
• pp.869-872
• /
• 2005

The purpose of this study is on the prediction of the acoustic performance of the lined rectangular plenum chamber which can be used in the HVAC systems. The lined plenum chamber is modeled as a piston driven rectangular tube without mean flow and the acoustic pressure in the lined chamber is obtained by superposing the three dimensional pressure due to each of uniformly and harmonically fluctuating pistons. The arbitrary locations of inlet/outlet ports as well as the acoustic higher order modes generated at the area discontinuities of the port chamber interfaces are taken into consideration. The four-pole parameters can be derived by imposing the proper boundary conditions on each inlet and outlet ports. The lining material on the internal wall is assumed to be a bulk-reacting model. A single weak variation statement which satisfies the fluctuating rigid piston condition and the pressure and displacement continuity condition at the interface between the lining material and the airway was developed. The set of cosine functions were used as the admissible function when applying the Rayleigh-Ritz method. Computed results are compared with those predicted by using the locally-reacting lining material and experimental results, respectively. There are a good agreement shown between the results by the Rayleigh-Ritz method and the experiment results. The derived transfer matrices can be easily combined with other four-pole parameters of different types of mufflers for the calculation of the whole system performance.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2007년도 춘계학술대회A
• /
• pp.372-377
• /
• 2007

For more than 2,500 years, surgical teaching has been based on the so called "see one, do one, teach one" paradigm, in which the surgical trainee learns by operating on patients under close supervision of peers and superiors. However, higher demands on the quality of patient care and rising malpractice costs have made it increasingly risky to train on patients. Minimally invasive surgery, in particular, has made it more difficult for an instructor to demonstrate the required manual skills. It has been recognized that, similar to flight simulators for pilots, virtual reality (VR) based surgical simulators promise a safer and more comprehensive way to train manual skills of medical personnel in general and surgeons in particular. One of the major challenges in the development of VR-based surgical trainers is the real-time and realistic simulation of interactions between surgical instruments and biological tissues. It involves multi-disciplinary research areas including soft tissue mechanical behavior, tool-tissue contact mechanics, computer haptics, computer graphics and robotics integrated into VR-based training systems. The research described in this paper addresses the problem of characterizing soft tissue properties for medical virtual environments. A system to measure in vivo mechanical properties of soft tissues was designed, and eleven sets of animal experiments were performed to measure in vivo and in vitro biomechanical properties of porcine intra-abdominal organs. Viscoelastic tissue parameters were then extracted by matching finite element model predictions with the empirical data. Finally, the tissue parameters were combined with geometric organ models segmented from the Visible Human Dataset and integrated into a minimally invasive surgical simulation system consisting of haptic interface devices and a graphic display.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
• /
• pp.138-138
• /
• 2009

Recently, thin-film solar cells of Cu(In,Ga)$Se_2$(CIGS) have reached a high level of performance, which has resulted in a 19.9%-efficient device. These conventional devices were typically fabricated using chemical bath deposited CdS buffer layer between the CIGS absorber layer and ZnO window layer. However, the short wavelength response of CIGS solar cell is limited by narrow CdS band gap of about 2.42 eV. Taking into consideration the environmental aspect, the toxic Cd element should be replaced by a different material. It is why during last decades many efforts have been provided to achieve high efficiency Cd-free CIGS solar cells. In order to alternate CdS buffer layer, ZnS buffer layer is grown by using chemical bath deposition(CBD) technique. The thickness and chemical composition of ZnS buffer layer can be conveniently by varying the CBD processing parameters. The processing parameters were optimized to match band gap of ZnS films to the solar spectrum and exclude the creation of morphology defects. Optimized ZnS buffer layer showed higher optical transmittance than conventional thick-CdS buffer layer at the short wavelength below ~520 nm. Then, chemically deposited ZnS buffer layer was applied to CIGS solar cell as a alternative for the standard CdS/CIGS device configuration. This CIGS solar cells were characterized by current-voltage and quantum efficiency measurement.

• 한국콘텐츠학회:학술대회논문집
• /
• 한국콘텐츠학회 2009년도 춘계 종합학술대회 논문집
• /
• pp.1055-1060
• /
• 2009

본 논문에서는 인터넷을 통한 운전면허 학과시험 학습시스템을 설계한다. 문항반응이론에 의거하여 학습자 능력모수를 정확히 측정하고, 측정된 학습자의 능력에 따라 최적의 평가문제와 학습콘텐츠를 동적으로 제공함으로써, 짧은 시간에 효과적으로 합격에 도달할 수 있도록 하는 개인 맞춤형 이러닝 시스템을 제안한다. 본 학습시스템은 콘텐츠 데이터베이스에 저장된 개념 단위 오브젝트 형태의 운전면허 학과시험용 학습콘텐츠들과 문제은행 데이터베이스에 저장된 운전면허 학과시험용 평가문제들을 연계하여, 학습자의 문항반응에 따라 최적의 문항과 콘텐츠를 제공할 수 있도록 설계된다. 각 문항들은 난이도, 변별도, 추측도의 문항모수를 보유한다. 또한 사용자 프로파일 데이터베이스에는 학습자들의 상태정보, 운전면허 학과시험용 평가문제들에 대한 피험자들의 문항반응을 유지 관리하고, 피험자들의 문항반응을 기초로 학습자 능력모수를 저장한다. 이들 데이터베이스는 인터페이스 에이전트, 콘텐츠 문항선택 & 피드백 에이전트 및 오프라인 추정기로 구성된 동작구조에 의하여 온라인 혹은 오프라인 형태의 동적 맞춤형 학습방식을 제공하여 최적의 학습과정을 제공한다.