• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2001년도 춘계학술대회논문집A
• /
• pp.636-643
• /
• 2001

Interference between the crossover leg of the reactor coolant system (RCS) and the pipe whip restraints (PWR) has brought a degradation issue of the integrity of the Reactor Coolant System in Westinghouse type nuclear power plants (NPPs) of Korea. According to the gap Inspect ion carried out during planned overhaul (Year 2000), interference between the crossover leg and the PWR was found in each RCS loop. This plant has had the high vibration problem on the RC pump 'B'. The reason for the high vibration in the RC pump 'B' had been massively surveyed and it was found that the crossover leg of RCS contacted with the PWR in hot condition. Since the contact between the crossover leg and the PWR changes the dynamic characteristics of the piping system for the RCS, this is considered as one reason for the high vibration. And a possibility of overstress on the crossover leg due to the contact with the PWR should be evaluated. Through performing RCS integrity analyses, subsequent actions were initiated to increase the gap between those parts. As the results of the appropriate separation between two parts, it was reported that there was no unusual noise or vibration during plant heat-up. In this paper, the evaluations for the gap between the crossover leg and the PWR and the structural integrity due to loop binding is described.

• 한국농업기계학회:학술대회논문집
• /
• 한국농업기계학회 1993년도 Proceedings of International Conference for Agricultural Machinery and Process Engineering
• /
• pp.1186-1195
• /
• 1993

The Japanese type combine harvester has adopted rubber crawlers for the driving mechanism from first production . However, combine harvesters with movable track rollers in the rubber crawler system have been adopted recently for the purpose of stability at the time of climbing over the footpaths between rice fields, as the results of the machines becoming large. However, the dynamic characteristics of movable track rollers have not been clarified. For this reason, the design of movable track rollers depends on trial and errors. It is known that vibration characteristics of the vehicle with movable track rollers are different from the vibration characteristics of the vehicles with fixed track rollers even though the track roller arrangements are the same. Therefore, the theoretical analyses of movable track rollers must be hurried in order to formulate a reasonable track roller arrangement design. the authors have studied the vibration characteristics of the rubber crawler ve icle with fixed track rollers. in this study, the dynamic model of the vehicle with movable track roller sis compared with the dynamic model of the vehicle with fixed track rollers. Next, motions are simulated to analyze the movable track rollers by expanding the motion equation which were constructed for the dynamic model of the fixed track rollers.

• Journal of Mechanical Science and Technology
• /
• 제17권9호
• /
• pp.1349-1357
• /
• 2003

This paper deals with verification of the theoretical model for dynamic behavior of Pipeline Inspection Gauge (PIG) traveling through high pressure natural gas pipeline. The dynamic behavior of the PIG depends on the differential pressure across its body. This differential pressure is generated by injected gas flow behind the tail of the PIG and expelled gas flow in front of its nose. To analyze the dynamic behavior characteristics such as gas flow in pipeline, and the PIG position and velocity, not only the mathematical models are derived, but also the theoretical models must be certified by actual pigging experiment. But there is not any found results of research on the experimental certification for dynamic behavior of the PIG. The reason is why the fabrication of the PIG as well as, a field application are very difficult. In this research, the effectiveness of the introduced solution using the method of characteristics (MOC) was certified through field application. In-line inspection tool, 30" geometry PIG, was fabricated and actual pigging was carried out at the pipeline segment in Korea Gas Corporation (KOGAS) high pressure system, Incheon LT (LNG Terminal) -Namdong GS (Governor Station) line. Pigging is fulfilled successfully. Comparison of simulation results with experimental results show that the derived mathematical models and the proposed computational schemes are effective for predicting the position and velocity of the PIG with a given operational conditions of pipeline.

• 한국지리정보학회지
• /
• 제9권2호
• /
• pp.11-19
• /
• 2006

하수관망은 인간의 삶을 증진시키거나 홍수와 같은 재해를 예방한다. 그러나 우리나라의 경우 하수처리시설에 대하여 관심을 가질 뿐, 관로에 대한 관리는 지도(map)의 수준에서 벗어나지 못하고 있다. 선형 객체의 경우 한 개의 선형에 단일 속성만 존재한다. 이 한계로 인하여 하수관거와 같은 선형 속성은 관리하기 힘들고, 선형의 부분적인(point type, line type) 속성 변화는 처리할 수 없다. 이에 본 연구는 속성 변화를 적용시킬 수 있는 방법을 찾고 적용하고자한다. 이를 위하여 Dynamic Segmentation을 이용하였다. DS는 선형객체 상의 정확한 위치에 속성값을 부여할 수 있는 장점을 가지고 있다. 이를 이용하여 하수관거 주위의 다양한 환경 변화를 적용 시킬 수 있었다. 또한 관거별 최대하수량을 정밀하게 계산할 수 있었다.

• 한국산업융합학회 논문집
• /
• 제23권5호
• /
• pp.789-798
• /
• 2020

This paper considers the development of the dynamic analysis model and simulation-based operation safety estimation of A-Frame to be applied to the test evaluation support vessel for real sea test. The support vessel will be manufactured by modifying the existing offshore support vessel. Also, development and installation of various sensors and supporting facilities for test evaluation are under preparation. Among these facilities, A-Frame is an equipment that transfers marine equipment from ship deck to the sea floor, and is being designed to transfer up to 50 ton class equipment. However, the A-Frame is a moving equipment using hydraulic cylinders. When the 50 ton equipment is attached and transferred to A-Frame, the buckling of cylinders may occur or A-Frame becomes inoperable due to the influence of huge inertia. For this reason, safety verification should be performed using dynamic analysis techniques that can take into account huge inertia forces in the design of A-Frame. Therefore, in this study, A-Frame and ship behavior were modeled using dynamic analysis method, and the applied loads of various equipment including hydraulic cylinder of A-Frame was measured and the operation safety review was performed.

• 한국지진공학회논문집
• /
• 제15권3호
• /
• pp.27-35
• /
• 2011

매설관의 동적해석법으로 Larbi(1995)와 정 등(2005)은 모드중첩법을 이용하여 매설관의 여러 단부경계조건에 대해 해석한 바 있다. 그러나 이 방법에서 얻고자 하는 해의 산정식은 유도과정이 매우 복잡할 뿐만 아니라 유도된 산정식마저 해를 얻기 위해선 별도의 수치해석 전산프로그래밍이 요구되므로 사실상 기술자가 실무에서 이용하기는 극히 어려운 해법으로 취급되고 있다. 이러한 모드 중첩법의 단점을 고려하여 이 해석법의 대안으로 실무에서 보다 쉽게 사용 가능한 3D 유한차분법을 제안하고자 한다. 이를위해 3D 동적 해석의 정확성을 검증한 후 그 결과를 모드중첩법의 결과와 비교 분석하여 매설관의 지진응답을 구하는 또 하나의 방법이 될 수 있음을 학인하였다.

• 대한건축학회논문집:계획계
• /
• 제35권4호
• /
• pp.25-36
• /
• 2019

Contemporary architecture is showing its deconstruction and departure from modern architecture based on rationality, such as reductionism or virtualism. This means a shift from a mechanistic and ecological world view to an organic and ecological view, from a deterministic reason to a reason for a possible secret static. This study examines the potential of fractals, a scientific theory of complexity that is emerging as a new paradigm in the 21st century, as an appropriate alternative to contemporary complexity architecture. The method and scope of this study were understood and its features were identified through literature and data research and prior study review. Based on the organic nature of fractal geometry, we analyzed the works of contemporary architects(Frank Gehry, Bernard Tschumi, Steven Holl, Zaha Hadid, Rem Koolhaas, Daniel Libeskind, Zvi Hecker, Ito Toyo) and studied the possibility of architectural design using the principle of fractal. As a result, fractal geometry, similar to the patterned order of nature, has an infinite set of organizational functionalities in architecture and can be applied in various aspects of design analysis. Architectural designs based on the fractal theory will require more research and development to realize dynamic design representation using digital computers.

• 산업경영시스템학회지
• /
• 제7권10호
• /
• pp.17-27
• /
• 1984

In order to foster the minor enterprises effectively we will have to take a proper step to control and adjust the excessive competitions of large-enterprises and minor as well as among minor enterprises, We should promote the relationship serialized between minor - and large - enterprises and establish mediation and control organizations and governmental policies to create re-subcontract among small and medium enterprises. To help the development of medium md small enterprises in Jeon-Buk area, therefore, Kunsan city should be designated as a Growth Position City. The reason is as follows. 1) Because Kunsan is located in Middle Western Seaside geographycally, and in the central place of our country as a key point of sea-transportation, we can cultivate the national land widely. 2) As an ocean gateway city of Kum River basin, Kunsan is a good place that can reform Hoh-nam inland of Kwang-iu, Jeon-ju, I-ri, and like places as well as central inland area of Dae-jeon, Chong-ju, etc.. 3) Kunsan is an advanced-base for constituting an industrial region of Weatern roast that has a spacious coastral industrial region and is connected with inland industrial park of Jeon-ju and I-ri and Jang-hang, Bi-in, etc.. From the above reason. Kunsan should be designated as a growth position city that can induce and promote the development of center of Western coast.

• 한국멀티미디어학회논문지
• /
• 제9권12호
• /
• pp.1709-1718
• /
• 2006

Users are able to use the information and service more free than previous wire network due to development of wireless network and device. For this reason, various studies on ubiquitous networks have been conducted. Various contexts brought in this ubiquitous environment, have recognized user's action through sensors. This results in the provision of better services. Because services exist in various places in ubiquitous networks, the application has the time of services searching. In addition, user's context is very dynamic, so a method needs to be found to recommend services to user by context. Therefore, techniques for reducing the time of service and increasing accuracy of recommendation are being studied. But it is difficult to quickly and appropriately provide large numbers of services, because only basic context information is stored. For this reason, we suggest DUPS(Dimension User Profile System), which stores location, time, and frequency information of often used services. Because previous technique used to simple information for recommending service without predicting services which is going to use on future, we can provide better service, and improve accuracy over previous techniques.

• 제어로봇시스템학회논문지
• /
• 제7권12호
• /
• pp.1015-1023
• /
• 2001

error behaviour can be considered as a linear combination of low amplitude random noise and abrupt jumps. The reason of jump appearance can be explained by the semi-shading effects(buildings, trees), jamming, high dynamic of vehicle and so on. This study describes the stand-alone GPS error jump smoothing algorithm which is developed based on the scalar adaptive filter. The algorithm consists of the coarse jump smoothing and the fine jump smoothing. On the coarse smoothing step, GPS velocities or position differences are used as the measurement for the scalar adaptive filter. The purpose of adaptive filter is to smooth the jump errors. The coarse positions are detennined by the integration of smoothed velocities. On the fine smoothing step, the differences between GPS positions and the coarse positions are smoothed by another scalar adaptive filter. The reason of fine smoothing is based on the facts that smoothing accuracy depends on the variance ofusefuJ signa\. The coarse smoothing which deal with the difference of positions provides the rough error removing. So the coarse smoothed velocities can have much more low amplitude than the raw ones. The fine smoothing procedure provides high quality of filtering process. Simulation results show the efficiency of proposed scheme.