• 산업기술연구
• /
• 제29권B호
• /
• pp.73-80
• /
• 2009

This paper is to investigate effect of B.G.I (Best Grouting Innovation) method on reinforcing ground. In this thesis, extensive literature review was performed to summarize theoretical backgrounds of grouting and to compare the applicability of different grouting methods. Unconfined compression test with specimen prepared by injecting different grouts of B.G.I, S.G.R and L.W methods and by changing the curing time were carried out to figure out characteristics of initial unconfined compression strength mobilized in the early stage. As results of test, the compression strength increases with curing times and specimen prepared with grouts of B.G.I method show greater values than others. On the other hands, the measured values of pH are in the range of 7-10 during tests. In field, preliminary construction to main construction at several sites were performed to confirm the effect of reinforcing the ground by application of B.G.I method. From the results of permeability test in field, SPT test and phenol reaction test, it was found that N values after grouting are greater than those before grouting and values of permeability in grouted ground is reduced significantly.

• 한국HCI학회:학술대회논문집
• /
• 한국HCI학회 2009년도 학술대회
• /
• pp.436-442
• /
• 2009

삼차원 재구성 기법은 대상을 파괴하지 않고도 그 내부 구조의 공간적 해석을 가능하게 해주는 단층 영상을 생성해주기 때문에, 산업, 의료분야에서 널리 사용되고 있다. 최근 영상 장비의 성능 향상으로 고해상도의 CT 영상을 얻을 수 있게 되었으나, 대용량 데이터를 재구성하기 위해 많은 시간이 소요된다. 본 논문에서는 재구성에서 가장 많은 시간이 소요되는 여과와 역투사 과정을 범용 그래픽스 하드웨어를 사용하여 최적화하는 방법을 제안한다. 여과에서는 네 장의 영상을 압축하여 동시에 처리하는 기법을 적용하고, 역투사 과정에서는 깊이 테스트를 이용하여 계산량을 줄이는 방법을 사용한다. 제안된 방법으로 구현된 GPU 기반 프로그램은 OpenMP 를 사용하여 최적화 된 CPU 기반 프로그램에 비해 약 50 배 이상 속도가 향상되었다.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제12권3호
• /
• pp.1243-1263
• /
• 2018

The two-stage linear discrimination analysis (TSLDA) is a feature extraction technique to solve the small size sample problem in the field of image recognition. The TSLDA has retained all subspace information of the between-class scatter and within-class scatter. However, the feature information in the four subspaces may not be entirely beneficial for classification, and the regularization procedure for eliminating singular metrics in TSLDA has higher time complexity. In order to address these drawbacks, this paper proposes an improved two-stage linear discriminant analysis (Improved TSLDA). The Improved TSLDA proposes a selection and compression method to extract superior feature information from the four subspaces to constitute optimal projection space, where it defines a single Fisher criterion to measure the importance of single feature vector. Meanwhile, Improved TSLDA also applies an approximation matrix method to eliminate the singular matrices and reduce its time complexity. This paper presents comparative experiments on five face databases and one handwritten digit database to validate the effectiveness of the Improved TSLDA.

• International Journal of Aeronautical and Space Sciences
• /
• 제17권4호
• /
• pp.622-630
• /
• 2016

In the operation of a low earth orbit satellite, a series of antenna commands are transmitted from a ground station to the satellite within a visibility window (i.e., the time period for which an antenna of the satellite is visible from the station) and executed to control the antenna. The window is a limited resource where all data transmission is carried out. Therefore, minimizing the transmission time for the antenna commands by reducing the data size is necessary in order to provide more time for the transmission of other data. In this paper, we propose a geometric compression method based on B-spline curve fitting using dominant points in order to compactly represent the antenna commands. We transform the problem of command size reduction into a geometric problem that is relatively easier to deal with. The command data are interpreted as points in a 2D space. The geometric properties of the data distribution are considered to determine the optimal parameters for a curve approximating the data with sufficient accuracy. Experimental results demonstrate that the proposed method is superior to conventional methods currently used in practice.

• 제어로봇시스템학회논문지
• /
• 제18권4호
• /
• pp.295-301
• /
• 2012

This paper deals with the design of robust DSMC (Discrete-Time Sliding Mode Control) scheme in order to overcome system uncertainty in steering system with mechanically joined structure. The proposed control scheme is one of robust control schemes based on system dynamics. Therefore, system dynamics required is not obtained from physical law but SCM (Signal Compression Method) through experiment in order to avoid complicate mathematical development and save time. However, SCM has a shortcoming that is the limitation of with $2^{nd}$ order linear model which does not include the dynamic of high-frequency band. Thus, considering system uncertainty, DSMC is designed. In addition, to reduce the chattering problem of DSMC, DSMC is derived from the reaching law and the Lyapunov stability condition. It is found that the proposed control scheme has robustness in spite of the perturbation of system uncertainty through computer simulation.

• Composites Research
• /
• 제34권5호
• /
• pp.269-276
• /
• 2021

프리프레그 압축성형(PCM, Prepreg Compression Molding) 공정은 고품질 CFRP(Carbon Fiber Reinforced Plastic) 제품을 제조할 수 있는 고속성형기술이다. 오토클레이브 공정에 비해 폐기물 발생이 적고 사이클타임을 크게 줄일 수 있어 항공우주 및 자동차 산업에서 다양한 연구가 진행되고 있다. 본 연구에서는 PCM 공정의 품질을 높이기 위해 프리프레그의 경화거동을 따라 프레스의 압축압력을 단계별로 증가시키는 성형법에 대해 연구하였고, 이러한 다단 압축 성형법이 우수한 품질의 CFRP 제품을 생산하고 사이클타임을 단축할 수 있는 좋은 수단임을 확인하였다. 그리고 상온에서 적층한 프리프레그를 금형에 투입하여 예열과 성형을 동시에 함으로써 별도의 예열 공정 없이 제품을 성형할 수 있었다. 또한 평판 성형에 최적화된 공정조건을 3차원 형상물에 동일하게 적용한 결과 외관상 평판과 유사한 제품을 공정조건 수립 과정 없이 만들 수 있었다.

• 한국농공학회논문집
• /
• 제56권1호
• /
• pp.101-107
• /
• 2014

It has been known that Terzaghi's consolidation theory is not well consistent with the consolidation phenomenon on the soft clay ground, but this theory has still been adopted normally in practice because there is no method for estimating the consolidation settlement and rate easier than Terzaghi's theory. It is impossible to map whole part of consolidation settlement vs time curve to the curve of Terzaghi'z average degree of consolidation. If the primary consolidation and the secondary compression are happened same time, it would be useless of trying to find the end of primary consolidation, but it is needed for using Terzaghi's theory that the end of consolidation is determined to the time of beginning consistency between the final settlement analyzed with curve fitting and the experimented consolidation settlement.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.2
• /
• pp.822-825
• /
• 2003

Maxwell displacement current (MDC) measurement has been employed to study the dielectric property of Langmuir-films. A method for determining the dielectric relaxation time $\tau$ of floating monolayers on water surface is presented. WC flowing across monolayers is analyzed using a rod-like molecular model. It is revealed that the dielectric relaxation time $\tau$ of monolayers in the isotropic polar orientational phase is determined using a liner relationship between the monolayer compression speed ${\alpha}$ and the molecular area Am. Compression speed ${\alpha}$ was about 30, 40, 50mm/min.

• Journal of Pharmaceutical Investigation
• /
• 제40권5호
• /
• pp.297-304
• /
• 2010

The present work focuses on preparation of olanzapine, orally dispersing tablets by direct compression method. Effect of super disintegrant crospovidone, disintegration time, drug content on in vitro release has been studied. A factorial design was employed in formulating a prompt dispersible tablet. The selected independent variables crospovidone and fmelt showed significant effect on dependent variables i.e. disintegration time and percent drug dissolved. Disintegration time and percent drug dissolved decreased with increase in the level of crospovidone. The similarity factor $f_2$ was found to be 97.48 for the developed formulation indicating the release was similar to that of the marketed formulation. Pharmacokinetics of olanzapine after single-dose oral administration of orally disintegrating tablet in normal volunteers were evaluated and the results showed that PK parameters (Cmax, Tmax, AUC) of the designed ODT matrix were similar to those of commercial product, Zyprexa Zydis$^{(R)}$ as a reference.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2002년도 하계학술대회 논문집 D
• /
• pp.2727-2729
• /
• 2002

In an emergency telemedicine system such as High-quality Multimedia based Real-time Emergency Telemedicine(HMRET) service, it is very important to examine the status of the patient continuously using the multimedia data including the biological signals(ECG, BP, Respiration, $SpO_2$) of the patient. In order to transmit these data real time through the communication means which have the limited transmission capacity. It is also necessary to compress the biological data besides other multimedia data. For the HMRET service, we developed the lossless biological signal compression program in MSVC++ 6.0 using DPCM method and JPEG Huffman table, and tested in an internet environment.