• 한국방재학회 논문집
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• 제8권4호
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• pp.61-66
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• 2008

상수관망의 노후화에 따른 잦은 파괴로 인해 보다 효율적인 상수관망 모니터링시스템 구축이 중요한 문제가 되었다. 상수관망의 모니터링 시스템의 하나인 "Smart-Pipe 시스템"은 영구적이며 포괄적인 자동화된 형태의 SIM 시스템으로 기존의 모니터링 시스템에 비해 많은 장점을 가지고 있다. Smart-pipe를 도입하기 위해서는 상수관 파괴를 미리 예측하여 갑작스러운 상수관 파괴를 막는 것과 같이 smart-pipe 설치를 통해 발생하는 간접적 이익의 정량화가 우선되어야 한다. 그러나 이와 관련된 연구는 국내외적으로 매우 미비한 실정이다. 본 연구에서는 smart-pipe의 개념을 기존 상수관 모니터링 시스템과 비교하였으며 smartpipe 설치에 따른 이익을 수용가불편시간으로 정량화하는 방안을 제시하였다. 제안된 방법을 고양시의 상수관망에 적용하여 적용성을 검증하였으며, smart-pipe시스템의 도입을 위한 기초자료로 활용될 수 있을 것으로 판단되었다.

• 한국CDE학회논문집
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• 제12권5호
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• pp.321-329
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• 2007

The present pipe modeling method requires detailed inputs from a designer to generate a pipe model, and thus it takes much time for the designer to perform such task. Moreover, the pipe model has no relation with the hull structure. Thus, it is time-consuming and requires much effort if design changes arise. In this study, a generating method that generates quickly many pipes using a pipe tray and a conversion method that converts automatically the pipes into objects related with the hull structure are proposed. A pipe modeling system based on the proposed methods is developed. The applicability of the developed system is demonstrated by applying it to the generation of the pipe model of a deadweight 300,000 ton VLCC(Very Large Crude oil Carrier). The results show that the developed system can quickly generate the pipe model in relation with the hull structure.

• 한국수자원학회논문집
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• 제35권6호
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• pp.665-675
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• 2002

상수관망에서 관로파열을 예측하고 파열영향을 감소시키는 작업은 관망의 신뢰도와 밀접한 관계가 있다. 기존의 상수관망의 설계에서는 관로의 배치 및 각 관로에 대한 수리학적 능력 및 파열에 대한 영향이 고려되지 않았다. 본 연구에서는 도학을 이용하여 상수관망의 기하학적 구성상태에 따른 관로 파열에 대한 영향을 예측하고 영향을 감소시켜 상수관망의 신뢰도를 증가시킬 수 있는 방법을 제시하였다. 기존의 상수관망은 폐합관로를 이루고 있지만 특정관로가 파열되었을 경우 적정한 유량공급이 불가능하여 관망의 대부분의 절점에 심각한 수두감소와 같은 부작용이 발생할 수 있었다. 본 연구에서 개발된 관로파괴 영향해석 기법을 이용하여 관망 설계시 적절한 관경 및 관로를 배치를 구성하여 관로 파괴시 발생하는 수요절점에서의 극단적인 수두감소를 극복할 수 있었고 사용자들에게 안정적인 유량공급이 가능하여 보다 신뢰성 있는 상수관망 시스템이 될 수 있었다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 춘계 학술발표회
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• pp.811-818
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• 2010

This paper presents the results of a numerical investigation on behavior of deep excavation wall system supported by steel pipe struts. A series of three-dimensional finite element analyses were carried out on a deep excavation project site which adopted steel pipe struts. The results indicated that the mechanical behavior of steel pipe supported deep excavation is comparable to that of a conventional H-pile supported deep excavation, although the steel pipe supported system is required less number of struts than the conventional H-pile strut system. Also shown is that the sectional stresses of the steel pipe support system are within the allowable values implying that the steel pipe support system can be effectively used as an alternative to conventional H-pile support system.

• Ocean Systems Engineering
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• 제10권3호
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• pp.317-332
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• 2020

This study examines the behaviors and properties of discharged liquid CO₂ from a long elastic pipe moving with a vessel for the oceanic CO₂ sequestration by considering pipe dynamics and vessel motions. The coupled vessel-pipe dynamic analysis for a typical configuration is done in the frequency and time domain using the ORCAFLEX program. The system's characteristics, such as vessel RAOs and pipe-axial-velocity transfer function, are identified by applying a broadband white noise wave spectrum to the vessel-pipe dynamic system. The frequency shift of the vessel's RAO due to the encounter-frequency effect is also investigated through the system identification method. Additionally, the time histories of the tip-of-pipe velocities, along with the corresponding discharged droplet size and Weber numbers, are generated for two different sea states. The comparison between the stiff non-oscillating pipe with the flexible oscillating pipe shows the effect of the vessel and pipe dynamics to the discharged CO₂ droplet size and Weber number. The pipe's axial-mode resonance is the leading cause of the fluctuation of the discharged CO₂ properties. The significant variation of the discharged CO₂ properties observed in this study shows the importance of considering the vessel-pipe motions when designing oceanic CO₂ sequestration strategy, including suitable sequestration locations, discharge rate, towing speed, and sea states.

• 상하수도학회지
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• 제29권6호
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• pp.659-666
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• 2015

In this study, Hazen-Williams C value of pipes in wide waterworks system was estimated and statistically analyzed. Hazen-Williams C value of water pipe was predicted after 20 years of service period. From the results, it was found that C value of water pipe for treated water maintained higher value of 110 after 20 years of installation. Furthermore, it was found that velocity coefficients of steel pipe for less than and more than 20 years of installation were 117.7 and 109.3, respectively. C value of ductile iron pipe for less than and more than 20 years of installation were 118.1 and 114.2, respectively. In this study, it was also found that small value of C is used in the design of water pipe system. Therefore, excessively bigger size of pipe can be determined in the design of water pipe system. From the results of present study, optimum value of C can be used to avoid the oversized design of water pipe system.

• 제어로봇시스템학회논문지
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• 제14권2호
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• pp.125-132
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• 2008

This paper describes a mobile inspection robot with an automatic pipe tracking system for a feeder pipe inspection in a PHWR. The robot is composed of two inch worm mechanisms. One is for a longitudinal motion along a pipe, and the other is for a rotational motion in a circumferential direction to access all of the outer surfaces of a pipe. The proposed mechanism has a stable gripping capability and is easy to install. An automatic pipe tracking system is proposed based on machine vision techniques to make the mobile robot follow an exact outer circumference of a curved feeder pipe as closely as possible, which is one of the requirements of a thickness measurement system for a feeder pipe. The proposed sensing technique is analyzed to attain its feasibility and to develop a calibration method for an accurate measurement. A mobile robot and control system are developed, and the automatic pipe tracking system is tested in a mockup of a feeder pipe.

• 유공압시스템학회:학술대회논문집
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• 유공압시스템학회 2010년도 춘계학술대회
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• pp.66-69
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• 2010

A punched pipe in a muffler for an automobile has many important variables, like location of holes in the pipe and length of the pipe related to noise reduction of a diffuser. This pipe is cut depending on length of product and this process, generally workers cut pipes by hands. In this process, there are many errors and it relies on the skill of workers, so it can happen that cycle time for complete product gets long and productivity gets low. Therefore, we need a vision system to distinguish holes in the punched pipe and a transfer system to set the cutting position automatically by moving the pipe depending on forward and backward part of the holes. This paper explains the development of an automatic transfer device which will cause the beating pipe to be cut correctly, exactly the same length as the product.

• 한국해양공학회지
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• 제20권5호
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• pp.9-14
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• 2006

This paper presents an analytical method, application of expansion, mechanical design, and integrated expansion design of subsea insulated pipe-in-pipe (PIP) systems. PIP system consists of a flowline and a casing pipe for the transport of high temperature and high pressure product from the subsea wells. To prevent heat lass from the fiowline, insulation material is applied between the pipes. The fiawline pipe and the casing pipe have mechanical connections through steel ring plate (water stops) and bulkheads. Pipeline expansion is defined by temperature, internal pressure, soil resistance, and interaction force between the flowline and the casing pipe. The results of the expansion analysis, the mechanical design of connection system of the two pipes and tie-in spool design are integrated for the whole PIP system.

• KIEAE Journal
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• 제10권1호
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• pp.65-72
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• 2010

The use of natural light has the potential for improving both the energy efficiency and indoor environmental quality in buildings. A light-pipe system can introduce daylight to spaces that would otherwise not be able to benefit from the advantages of daylight penetration. For the light-pipe system to be widely used in Korea, it is important to quantify its daylighting performance with due consideration regarding the effects imposed by the local climate conditions. This paper presents the evaluation results of existing semi-empirical models to predict daylighting performance of a light-pipe system. The evaluation of the existing models was based on the monitoring data obtained from a underground parking lot in which the light-pipe system was installed. Comparisons were made between the predicted and the monitored data obtained from the study. The results indicated that semi-empirical models which was developed using the experimental data obtained under the Korean climatic conditions had a good prediction performance. We also quantified the effects caused by sky conditions, solar altitudes, room dimensions, and the aspect ratio of a light-pipe system on both the daylighting performance of the light-pipe system and the indoor illuminance distributions of the space using the semi-empirical model. Finally, this paper provides the design guideline of the light-pipe system for its application to an underground parking lot space.