• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.2
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• pp.9-14
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• 2018

The function of gas springs is based on the compression of a gas. They are used in a wide variety of industries, and demand for them is increasing. Gas springs can be divided into compression and extension springs. Extension springs have not been studied much in relation to control of the piston speed, unlike compression springs. In this study, the magnitude of the piston rebound pressure was theoretically predicted by calculating the pressure loss in a double-cylinder extension gas spring. Numerical simulations of the piston behavior were carried out for small and large amounts of friction between the piston and the cylinder. FLUENT was used for the simulation with a 6-DOF model and UDF to simulate the behavior of the piston. The calculation regions of the front and rear of the piston were separated, and different types of grids were generated in the regions to implement a dynamic mesh using only a layering method. The results show that the piston returns with the target speed in both cases. However, the patterns of the piston behavior reaching the final speed are different.

• Journal of Satellite, Information and Communications
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• v.10 no.2
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• pp.46-53
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• 2015

Visible Light Communication (VLC) is effective way to realize the light device and communication device using a Light Emitting Diode (LED) simultaneously. VLC has high security for Field Of View (FOV) communication area, also which is possible to transmit the high data rate using visible light. In VLC, transmitting the divided data by the RGB channels is higher data rate than transmitting the same data by RGB channels. However, it occurred the burst error by scattering and reflection of visible light which is impossible to restore that. To solve the problem, we proposed the 2-step interleaving scheme that high data rate and improve the performance of BER in VLC. The proposed system implements cyclic interleaving and convolutional interleaving that is able to be standardized the performance of RGB channels and improve the performance of BER using error correction.

• The KIPS Transactions:PartB
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• v.9B no.1
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• pp.99-104
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• 2002

Existing methods of object tracking use template matching, re-detection of object boundaries or motion information. The template matching method requires very long computation time. The re-detection of object boundaries may produce false edges. The method using motion information shows poor tracking performance in moving camera. In this paper, a robust object tracking algorithm is proposed, using projected motion and histogram intersection. The initial object image is constructed by selecting the regions of interest after image segmentation. From the selected object, the approximate displacement of the object is computed by using 1-dimensional intensity projection in horizontal and vortical direction. Based on the estimated displacement, various template masks are constructed for possible orientations and scales of the object. The best template is selected by using the modified histogram intersection method. The robustness of the proposed tracking algorithm has been verified by experimental results.

• The Inventors News
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• no.55
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• pp.1-16
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• 2007

선진국가 선도하는 창의적 여성경제리더 양성하자/발명지도사.시제품제작지원 시행/발행인 칼럼/특허심사처리 세계에서 가장 빠르다/글로벌 기업, 한국 특허청에 심사의뢰 쇄도/국유특허권 온라인 전자계약 시행/특허기술, "기술경매" 로 산다/여성발명인 거유 활동 영역 넓어/감귤와인 특허획득 이어 독일 등 해외 수출 기대/미더덕 냉동 않고도 장기 보관/특허민원서식 대폭 감축/특허청, 개도국 지원사업 대폭 확대/기상청, 날씨예보기술로 특허 받아/우리나라 국제특허출원 수준 세계 6위/건강관련 브랜드 상표출원 증가/친환경수로관 '도룡용 살린다'/고등학교에 첫 발명창작과 개설/욕조, 웰빙 휴식공간으로 자리매김/가습기, 공기정화.탈취.방향 등 다기능화/패치제 특허출원 해마다 증가/일 특허청, 분할출원기간 30일 연장/중 법원, 비아그라 특허군 인정/국내 제약사 유유 "미머크사 특허 침해" 주장/삼성전자, 지난해 미 특허 2천4백53건으로 2위/기업심볼마크는 단순, 상표는 길어져/LG전자 "대우일렉이 드럼세탁기 특허권 침해했다"/유.무선 통합 '원폰 서비스' 기술 개발/암환자 울린 과대광고제품 1백억원대 판매 적발/맥도날드 '해피밀' 광고 퇴출/세원셀론텍, 콜라겐 원천기술 특허/역사 속의 발명품/하루 10분 발명교실/특허Q&A/'S&D Trecap' 황지경 대표/경기도, 여성분야 소상공인창업자금 신설/특허청, 세계지식재산기구(WIPO) 진출확대/아이디어 착상 및 발명 기법/여성발명 활성화만이 국가경쟁력 키우는 첩경/히로자키의 광엽수 진액/해외 네티즌 인기 화제의 발명품들/여성기업 생산제품 MAS시 적격성 평가 면제/특허청, 시작품제작지원 5천만원까지 확대/지난해 짝파라치에게 3억2천3백만원 포상금 지급/입체방송 분야 특허출원 봇물/트랜스지방 퇴출 시민단체 '토트랜스 클럽' 출현/한국여성발명협회 회원사 발명품 가이드/

• Composites Research
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• v.30 no.4
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• pp.247-253
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• 2017

In this study, the mechanical behavior and interface properties of boron nitride nanotube-poly(methyl methacrylate) nanocomposites are predicted using the molecular dynamics simulations and the double inclusion model. After modeling nanocomposite unit cell embedding single-walled nanotube and polymer, the stiffness matrix is determined from uniaxial tension and shear tests. Through the orientation average of the transversely isotropic stiffness matrix, the effective isotropic elastic constants of randomly dispersed microstructure of nanocomposites. Compared with the double inclusion model solution with a perfect interfacial condition, it is found that the interface between boron nitride nanotube and polymer matrix is weak in nature. To characterize the interphase surrounding the nanotube, the two step domain decomposition method incorporating a linear spring model at the interface is adopted. As a result, various combinations of the interfacial compliance and the interphase elastic constants are successfully determined from an inverse analysis.

• Journal of the Korean Society of Propulsion Engineers
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• v.4 no.2
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• pp.21-30
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• 2000

Numerical design optimization techniques are implemented for the improvement of the ram accelerator performance. The design object is to find the minimum ram tube length required to accelerate projectile from initial velocity $V_o$ to target velocity $V_e$. The premixture is composed of $H_2$, $O_2$, $N_2$ and the mole numbers of these species are selected as design variables. The objective function and the constraints are linearized during the optimization process and gradient-based Simplex method and SLP(Sequential Linear Programming) have been employed. With the assumption of two dimensional inviscid flow for internal flow field, the analyses of the nonequilibrium chemical reactions for 8 steps 7 species have been performed. To determined the tube length, ram tube internal flow field is assumed to be in a quasi-steady state and the flow velocity is divided into several subregions with equal interval. Hence the thrust coefficients and accelerations for corresponding subregions are obtained and integrated for the whole velocity region. With the proposed design optimization techniques, the total ram tube length had been reduced 19% within 7 design iterations. This optimization procedure can be directly applied to the multi-stage, multi-premixture ram accelerator design optimization problems.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.43 no.3 s.309
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• pp.17-24
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• 2006

In this paper, an algorithm for anchor frame detection in news video is proposed, which consists of four steps. In the first step, the cumulative histogram method is used to detect shot boundaries in order to segment a news video into video shots. In the second step, skin color information is used to detect face regions in each shot boundary. In the third step, color information of upper body regions is used to extract anchor object, which produces candidate anchor frames. Then, from the candidate anchor frames, a graph-theoretic cluster analysis algorithm is utilized to classify the news video into anchor-person frames and non-anchor frames. Experiment results have shown the effectiveness of the proposed algorithm.

• Journal of the Korean Society of Radiology
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• v.1 no.2
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• pp.23-30
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• 2007

This paper presents a method of generating 3-dimensional images by preprocessing 2-dimensional abdominal images obtained using CT (computed tomography) and MRI (magnetic resonance imaging) through segmentation, threshold technique, etc. and apply the method to virtual endoscopy. Three-dimensional images were visualized using indirect volume rendering, which can render at high speed using a general-purpose graphic accelerator used in personal computers. The algorithm used in the rendering is Marching Cubes, which has only a small volume of calculation. In addition, we suggested a method of producing 3-dimensional images in VRML (virtual reality modeling language) running on the Web browser without a workstation or an exclusive program. The number of nodes, the number of triangles and the size of a 3-dimensional image file from CT were 85,367, 174,150 and 10,124, respectively, and those from MRI were 34,029, 67,824 and 3,804, respectively.

• The KIPS Transactions:PartA
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• v.19A no.2
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• pp.101-112
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• 2012

In recently years, distributed real-time software has performed important roles in various areas. Real-time applications should be performed with satisfying strict constraints on response time. Usually real-time applications are developed on the real-time supporting middleware such as TMO(Time-triggered, Message-triggered Object), CORBA/RT, and RTAI. However, it is not easy to develop applications using them since these real-time middleware are unfamiliar to programmers. In this paper, we propose an automatic code generator for real-time application based on TMO in order to reduce development costs. For increasing or reflecting the characteristics of TMO into the design model, SpM and SvM methods are added into the class diagram, which have time constraints as their properties. And behaviors of them are represented as separated regions on state machine diagram in different abstract level. These diagrams are inputted into TMO-based code automatic generator, which generates details of the TMO class. Our approach has advantages for decreasing effort and time for making real time software by automatically generating TMO codes without detailed knowledge of TMO.

• KIPS Transactions on Computer and Communication Systems
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• v.6 no.12
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• pp.487-496
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• 2017

In MySQL InnoDB, there are two ways of storing data. One is to create a separate tablespace for each table and store it separately. Another is to store all table and index information in a single system tablespace. You can use this information to recover deleted data from the record. However, in most of the current database forensic studies, the former is actively researched and its structure is analyzed, whereas the latter is not enough to be used for forensics. Both approaches must be analyzed in terms of database forensics because their storage structures are different from each other. In this paper, we propose a method for recovering deleted records in a method of storing records in IBDATA file, which is a single system tablespace. First, we analyze the IBDATA file to reveal its structure. And introduce delete record recovery algorithm which extended to an unallocated page area which was not considered in the past. In addition, we show that the recovery rate is improved up to 68% compared with the existing method through verification using real data by implementing the algorithm as a tool.