• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.99-104
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• 2006

Accurate flow rate distribution has been become a very important part for controling of air change rate since the introduction of house ventilation system. An inappropriate selection of fan due to Incorrect prediction of friction loss makes waste energy. The purpose of this study is to recognize applicability of T-Method at house ventilation system by comparing experiment with T-method, The result of this study is as follows Flow rate is small amount in a house, so duct size must be accurate. And duct design with Equal Friction Loss Method presented large error range. Equal friction loss method is not fit to applicate small amount air flow rate. T-Method predicts accurate flow rate comparatively in a house ventilation system. Error range was 3.5%.

• 한국해양학회지
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• 제28권3호
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• pp.192-201
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• 1993

쯔나미파에 의한 피해를 줄이기 위해서는 쯔나미파를 재현할 수 있는 방법의 개발 이 필요하다. 본 논문에서는 Sign Method를 도입하여 검조기에 기록된 쯔나미파를 분 석하고 재현해 봄으로써, 쯔나미파 분석에서의 Sign Method의 사용가능성을 검토하였 다. 쯔나미파의 시계열자료 Y(t)는 각 쯔나미의 발생특징을 반영하는 함수인 source evolution function E(t')와 파가 전파되는 지역의 특징을 나타내는 함수인 wave propagation function K9t-t')의 convolution 적분에 의해 나타낼 수 있다. Y(t)=.int. E(t')K(t-t')dt' 일본의 6개 지점과 한국의 9개 지점에서 기록된 1940년, 1964년, 1983년의 쯔나미파를 분석하여 sourve function 들과 wave function들을 구하 고, 두 함수를 이용하여 기록자료도 재현해 보았다. 우리 나라 동해안처럼 쯔나미의 진원지로부터 멀리 위치한 지역에서는 Sign Metho가 효과적인 방법임을 알 수 있었다. 또한, 기록되지 않은 쯔나미파도 인접지점의 source function 과 다른 시기의 쯔나미 에 대한 wave function을 이용하여 추정할 수 있다.

• 설비공학논문집
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• 제10권4호
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• pp.389-397
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• 1998

A loop duct system is often found in a VAV-HVAC(variable air volume heating, ventilating and air conditioning) design. It is known that the simple T-method is not be applicable to the loop duct system and cannot be used to calculate the flow rate and the pressure drop at each duct section of the loop duct system. In this paper, the extended T-method has been developed and it is found to be applicable to the loop duct system to which the simple T-method cannot be applied. The validity of the extended T-method has been verified by using to solve for a simple, ideal loop duct system for which there exists analytical solution. In addition, the extended T-method is employed to compute the loop duct system of a real building with an area of 380$m^2$. The results show that the computed flow rate at the exit differs from the designed flow rate by a range of -13.6~43.5 %. Consequently, three design factors must be adjusted in order that the flow rate may be balanced. These include the duct sizes, in terms of their lengths and diameters, the sub-duct locations and the positioning of damper which is found upstream of the exit duct.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국내학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.365-369
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• 1993

In this paper, the new M/T method for motor speed detection is proposed. This method can be able to reduce the dead time compared with it when Ohmae's M/T method is implemented. And the comparsion of the dead time length between the Ohmae's method and the proposed method is analyzed quantitatively. Actually we implemented the new proposed M/T method using the hardware and software and verified the effectiveness of the proposed M/T method.

• Journal of Microbiology and Biotechnology
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• 제18권4호
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• pp.624-630
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• 2008

Terminal restriction fragment length polymorphism (T-RFLP) is a method that has been frequently used to survey the microbial diversity of environmental samples and to monitor changes in microbial communities. T-RFLP is a highly sensitive and reproducible procedure that combines a PCR with a labeled primer, restriction digestion of the amplified DNA, and separation of the terminal restriction fragment (T-RF). The reliable identification of T-RF requires the information of nucleotide sequences as well as the size of T-RF. However, it is difficult to obtain the information of nucleotide sequences because the T-RFs are fragmented and lack a priming site of 3'-end for efficient cloning and sequence analysis. Here, we improved on the T-RFLP method in order to analyze the nucleotide sequences of the distinct T-RFs. The first method is to selectively amplify the portion of T-RF ligated with specific oligonucleotide adapters. In the second method, the termini of T-RFs were tailed with deoxynucleotides using terminal deoxynucleotidyl transferase (TdT) and amplified by a second round of PCR. The major T-RFs generated from reference strains and from T-RFLP profiles of activated sludge samples were efficiently isolated and identified by using two modified T-RFLP methods. These methods are less time consuming and labor-intensive when compared with other methods. The T-RFLP method using TdT has the advantages of being a simple process and having no limit of restriction enzymes. Our results suggest that these methods could be useful tools for the taxonomic interpretation of T-RFs.

• 대한기계학회논문집A
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• 제33권2호
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• pp.127-134
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• 2009

T-splines are recently proposed geometric modeling tools. A T-spline surface is a NURBS surface with T-junctions and is defined by a control grid called T-mesh. Local refinement can be performed very easily for T-splines while it is limited for B-splines or NURBS. Using T-splines, patches with unmatched boundaries can be combined easily without special technique. In this study, the analysis methodology using T-splines is proposed. In this methodology, T-splines are used both for description of geometries and for approximation of solution spaces. Two-dimensional linear elastic and dynamic problems will be solved by employing the proposed T-spline finite element method, and the effectiveness of the current analysis methodology will be verified.

• Journal of the Korean Statistical Society
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• 제34권3호
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• pp.245-261
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• 2005

The marginal distribution of X is considered when (X, Y) has a truncated bivariate t-distribution. This paper mainly focuses on the marginal nontruncated distribution of X where Y is truncated below at its mean and its observations are not available. Several properties and applications of this distribution, including relationship with Azzalini's skew-normal distribution, are obtained. To circumvent inferential problem arises from adopting the frequentist's approach, a Bayesian method utilizing a data augmentation method is suggested. Illustrative examples demonstrate the performance of the method.

• Computers and Concrete
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• 제17권1호
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• pp.67-86
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• 2016

Strengthening as well as correcting unsightly deflections of reinforced concrete (RC) beam may be accomplished by retrofitting. An innovative way to do this retrofitting that is proposed in this study utilizes turnbuckle to apply external post-tensioning. This Turnbuckle External Post-Tensioning (T-EPT) was experimentally proven to improve the serviceability and load carrying capacity of reinforced concrete beams. The T-EPT system comprises a braced steel frame and a turnbuckle mechanism to provide the prestressing force. To further develop the T-EPT, this research aims to develop a numerical scheme to analyze the structural performance of reinforced concrete beams with this kind of retrofitting. The fiber method analysis was used as the numerical scheme. The fiber method is a simplified finite element method that is used in this study to predict the elastic and inelastic behavior of a reinforced concrete beam. With this, parametric study was conducted so that the effective setup of doing the T-EPT retrofitting may be determined. Different T-EPT configurations were investigated and their effectiveness evaluated. Overall, the T-EPT was effective in improving the serviceability condition and load carrying capacity of reinforced concrete beam.

• 한국융합학회논문지
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• 제9권4호
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• pp.57-63
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• 2018

IoT 장치는 클라우드 환경에서 다양한 역할과 기능을 수행할 수 있도록 여러 분야에서 사용되고 있다. 그러나, IoT 장치를 안정적으로 제어할 수 있는 접근제어에 대한 방안은 아직 구체적으로 제시되고 있지 않은 상황이다. 본 논문에서는 클라우드 환경에서 사용되고 있는 IoT 장치의 안정적인 접근을 수행할 수 있는 계층적 기반의 다단계 속성 접근제어 기법을 제안한다. 제안 방법은 IoT 장치의 원활한 접근을 돕기 위해서 IoT Hub을 두어 IoT 장치에 고유한 ID 키(보안 토큰)를 제공할 뿐만 아니라 수 있도록 하는 X.509 인증서 및 개인 키를 IoT Hub에서 인증하도록 하여 IoT 장치의 개인키를 IoT 장치 외부에서 알 수 없도록 하였다. 성능평가 결과, 제안방법은 기존 기법보다 인증 정확도가 평균 10.5% 향상되었으며 처리 시간도 14.3% 낮은 결과를 얻었다. IoT 속성 수에 따른 IoT Hub의 오버헤드는 기존 기법보다 9.1% 낮은 결과를 얻었다.

• 한국정보과학회논문지:소프트웨어및응용
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• 제41권8호
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• pp.545-556
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• 2014

최근 각광받고 있는 연구분야 중 하나인 Internet of Things (IoT)은 사물들이 네트워크 상에 연결되어 있는 있는 컴퓨팅 환경으로, 이 환경을 구성하는 여러 IoT 디바이스들이 협업을 통해 사용자에게 유용한 기능을 제공할 수 있는 장점이 있다. IoT 디바이스의 제한된 배터리 수명, 이동성과 같은 동적인 특성으로 인해 IoT 디바이스의 상태는 계속해서 변하게 되며, 이로 인해 IoT 디바이스를 관리하는 데에 어려움이 있다. 본 논문에서는 IoT 디바이스의 동적인 특성에 의한 IoT 디바이스 관리 문제를 도출하고 이를 해결하기 위한 디바이스 관리 프레임워크를 제안한다. 그리고, 디바이스 검색, 디바이스 상태 확인, 디바이스 선택 및 연결, 그리고 디바이스 교체를 포함한 네 가지의 기법을 제시한다. 또한 제시된 기법들을 기반으로 디바이스 관리 프레임워크를 구현하고 실험을 통하여 제안한 기법들의 실효성을 검증한다.