• Journal of the Korean Society of Hazard Mitigation
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• v.8 no.4
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• pp.61-66
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• 2008

As the water distribution system which is one of the critical lifeline system is deteriorated and pipe failures occur frequently, the more efficient pipe monitoring system becomes a critical issue in the water industry. One of the pipe monitoring systems is called "Smart-pipe System" which is permanent, comprehensive and an automated SIM (Structural Integrity Monitoring) system and has superiorities to existing monitoring system. To implement a smart-pipe system on a water distribution system, assessment of its indirect benefit obtaining from smartpipe such as the ratio of preventing water main failures must be preceded. However, only some researches on this field have been performed. In this paper, the concept of smart-pipe system is compared with the current monitoring systems for a water distribution system, and a method to quantify its benefit using the inconvenient time for customers is suggested. The suggested method was applied to a real water distribution system to estimate its applicability and benefit.

• Korean Journal of Computational Design and Engineering
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• v.12 no.5
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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.

• Journal of Korea Water Resources Association
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• v.35 no.6
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• pp.665-675
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• 2002

It is very closely related with the reliability of the pipe network to predict pipe burst and diminish burst effect in water distribution system. Most of the engineers have not consider pipe layout and the effect of pipe burst in conservative pipe network design. In this study, The effect of pipe burst in the network is analyzed with respect to pipe network geometric topology and the method of increasing the system reliability is presented by reducing pipe-burst effect. In existing pipe system, it is only designed to the closed loop system but in case of each pipe burst, it cannot transmit appropriate water to consumers and occurs severe hydraulic head drop in many nodes. The techniques developed in this study allow proper pipe diameter and pipe layout to pipe system through the analysis of pipe-burst effect. Thus, when each pipe is bursted, pipe system is prevented from severe pressure head drop in demand nodes and can supply stable flowrate to consumer.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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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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• v.10 no.3
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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.

• Journal of Korean Society of Water and Wastewater
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• v.29 no.6
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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.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.2
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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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• 2010.06a
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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.

• Journal of Ocean Engineering and Technology
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• v.20 no.5 s.72
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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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• v.10 no.1
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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.