• Advanced Composite Materials
• /
• 제17권3호
• /
• pp.247-258
• /
• 2008

This paper is concerned with the long-term performance of geo-textile (GT) composites in terms of creep deformation and frictional properties. Composites of PVA GT and HDPE GM were made to investigate the advanced properties of long-term performance related to waste landfill applications. The same experiments were also performed for typical polypropylene and polyester GT and compared to PVA GT/HDPE GM composites. We also develop high performance GT composites with GM by using PVA GT, which is capable of improving the frictional properties and thus enhances long-term performance of GT composites. Experimental study reveals that the friction coefficient of GT composites is relatively large compared with those of polyester and polypropylene non-woven GT as long as the friction media has similar size to the particles of domestic standard earth. In addition, the geo-composites bonded with geo-grid by a chemical process were investigated experimentally in terms of strain evaluation and creep response values. Geo-grid plays an important role as a reinforcing material. Three kinds of geo-grid were prepared as strong yarn polyester and they were woven type, non-woven type, and wrap knitted type. The sample geo-grids were then coated with PVC. The rib tensile strength tests were conducted to evaluate geo-grid products in terms of tensile strength with regard to single rib. The test was performed according to GRI-GGI. It was concluded again from the experiments that the tensile and creep strains of the geo-grid showed such stable values that the geo-grid prepared in this study could protect geo-textile partially in practical structures.

• 한국정보통신학회논문지
• /
• 제12권1호
• /
• pp.172-182
• /
• 2008

그리드 환경에서 워크플로우 프로세스 단위 기반의 애플리케이션 컨텐츠는 특정한 문제 해결을 위한 실질적인 작업이며, 그리드 자원에 분산 배포되고 서로 연관되어 실행되기 때문에 협업 환경을 구성하는 것은 매우 중요한 부분이다. 그리고 대부분의 협업은 워크플로우를 통하여 구체화되고, 그리드 환경에서 협업처리를 위한 미들웨어로는 Globus toolkit이 대표적이다. 하지만 이 미들웨어는 그리드 환경 구축을 위한 기본 서비스들만을 제공하고, 협업을 할 수 있는 워크플로우 생성, 작업 스케줄링, 프로세스 단위 기반의 애플리케이션 관리 같은 부분은 적용되지 않는다. 또한 Globus Toolkit은 대형화된 그리드 커뮤니티 구성에는 적합하나, 소규모 대다수가 특정한 운영 체제로 구성된 대형화된 그리드 커뮤니티 구성에는 적합하지 않고, 소규모 대다수가 특정한 운영체제로 구성된 그리드 커뮤니티 구성에는 부적합하다. 따라서 본 논문에서는 그리드 환경에서 소규모 협업 처리에 효율적인 워크플로우 프로세스 단위 기반의 애플리케이션 배포 시스템을 제안한다. 이 시스템은 애플리케이션 배포, 그리드 커뮤니티에 구성된 자원관리 등의 역할을 통해 효율적인 협업 환경을 지원한다. 또한 워크플로우 프로세스 단위 기반의 애플리케이션간 연관 관계 사전을 만들어 협업에 필요한 애플리케이션간의 정보 및 연관 관계를 표현하여 애플리케이션을 배포하는 기반 정보로도 활용한다.

• 한국전자파학회논문지
• /
• 제12권2호
• /
• pp.278-284
• /
• 2001

본 논문에서는 기울어진 금속 경계면을 삼각형 격자법으로 해석하고, 계단 근사법과 비교하였다. 특시, 삼각형 격자법에서 금속-유전체간의 경사각도에 대한 오차 범위를 밝혔다. 그결과, 삼각형 격자법에서 경사각이 30。이상 60。이하인 경우, 계단 근사법에 비하여 정확도가 향상되고, 계산속도 및 메로미를 줄일 수 있었다. 그러나 이 범위를 벗어나는 경우, 격자의 한 변의 길이가 상대적으로 늘어나 정확한 해석이 되지 않았다.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2003년도 하계종합학술대회 논문집 Ⅲ
• /
• pp.1621-1624
• /
• 2003

As the entities participating Grid become larger, performance requirement for the LDAP-based GIS(Grid Information Service) goes beyond that provided by a stand-alone single LDAP server. This entails the exploration of distributed LDAP systems. This paper presents the performance evaluation respectively for a distribution-based and a replication-based LDAP model. The analysis is based on an analytic performance model for each distributed system which is obtained by applying the M/M/1 queuing model. The performance evaluation made to these analytic models reveals that the distribution-based and the replication-based model show a significant tradeoff in their performance with respect to the system size as well as the amount of system load.

• Journal of Power Electronics
• /
• 제16권4호
• /
• pp.1541-1550
• /
• 2016

This paper presents a theoretical analysis and comparisons of active power filter (APF) and hybrid power filter (HPF) systems, given terminal constraints of harmonic compensations in nonlinear loads. Despite numerous publications for the two types of filters, the features and differences between them have not been clearly explained. This paper presents a detailed analysis of the operations of a HPF inverter along with those of passive power filters (PPFs). It also includes their effects on the power factor at the grid. In addition, a theoretical analysis and a systematic comparison between the APF and HPF systems are addressed based on system parameters such as the source voltage, output power, reactive component size, and power factor at the grid terminals. The converter kVA ratings and dc-link voltage requirements for both topologies are considered in the presented comparisons

• Journal of Electrical Engineering and Technology
• /
• 제8권6호
• /
• pp.1400-1408
• /
• 2013

This paper proposes a new grid-tied power converter for battery energy storage, which is composed of a 2-stage DC-DC converter and a PWM inverter. The 2-stage DC-DC converter is composed of an LLC resonant converter connected in cascade with a 2-quadrant hybrid-switching chopper. The LLC resonant converter operates in constant duty ratio, while the 2-quadrant hybrid-switching chopper operates in variable duty ratio for voltage regulation. The operation of proposed system was verified through computer simulations. Based on computer simulations, a hardware prototype was built and tested to confirm the technical feasibility of proposed system. The proposed system could have relatively higher efficiency and smaller size than the existing system.

• 한국태양에너지학회:학술대회논문집
• /
• 한국태양에너지학회 2008년도 추계학술발표대회 논문집
• /
• pp.337-340
• /
• 2008

As a 'Construction of Information System on GIS based and Resource Map', establish the strategic of design about construction of Spatial Data Warehouse for New & Renewable Energy For Construction of comfortable Spatial Data Warehouse, It suggested The Construction of Spatial Data Warehouse on Block(Grid) Based with Analyze into the old Data & Method of Study. For Decide the Block(Grid) Size, We need The Study of Data & Method. Also, we expect Standardize The Process of Change & Apply with Data. make the best use of New & Renewable Energy Part

• Journal of Positioning, Navigation, and Timing
• /
• 제9권1호
• /
• pp.23-31
• /
• 2020

It is essential to estimate the vehicle localization for an autonomous safety driving. In particular, since LIDAR provides precise scan data, many studies carried out to estimate the vehicle localization using LIDAR and pre-generated map. The road marking always exists on the road because of provides driving information. Therefore, it is often used for map information. In this paper, we propose to generate the Gaussian mixture map based on road-marking information and localization method using this map. Generally, the probability distributions map stores the single Gaussian distribution for each grid. However, single resolution probability distributions map cannot express complex shapes when grid resolution is large. In addition, when grid resolution is small, map size is bigger and process time is longer. Therefore, it is difficult to apply the road marking. On the other hand, Gaussian mixture distribution can effectively express the road marking by several probability distributions. In this paper, we generate Gaussian mixture map and perform vehicle localization using Gaussian mixture map. Localization performance is analyzed through the experimental result.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제10권3호
• /
• pp.1071-1090
• /
• 2016

Most of scheduling methods in the Grid only consider one special attribute of the resource or one aspect of QoS (Quality of Service) of the job. In this paper, we focus on the problem that how to consider two aspects simultaneously. Based on the requirements of the jobs and the attributes of the resources, jobs are categorized into three kinds: CPU-overload, memory-overload, and bandwidth-overload jobs. One job may belong to different kinds according to different attributes. We schedule the jobs in different categories in different orders, and then propose a scheduling method-MTS (multiple attributes scheduling method) to schedule Grid resources. Based on the comparisons between our method, Min-min, ASJS (Adaptive Scoring Job Scheduling), and MRS (Multi-dimensional Scheduling) show: (1) MTS reduces the execution time more than 15% to other methods, (2) MTS improves the number of the finished jobs before the deadlines of the jobs, and (3) MTS enhances the file size of transmitted files (input files and output files) and improves the number of the instructions of the finished jobs.

• 한국전산유체공학회:학술대회논문집
• /
• 한국전산유체공학회 2007년도 춘계 학술대회논문집
• /
• pp.177-181
• /
• 2007

Present study examines the numerical issues of cell structure simulation for various regimes of detonation phenomena ranging from weakly unstable to highly unstable detonations. Inviscid fluid dynamics equations with $variable-{\gamma}$ formulation and one-step Arrhenius reaction model are solved by a MUSCL-type TVD scheme and 4th order accurate Runge-Kutta time integration scheme. A series of numerical studies are carried out for the different regimes of the detonation phenomena to investigate the computational requirements for the simulation of the detonation wave cell structure by varying the reaction constants and grid resolutions. The computational results are investigated by comparing the solution of steady ZND structure to draw out the minimum grid resolutions and the size of the computational domain for the capturing cell structures of the different regimes of the detonation phenomena.