• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.3
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• pp.143-152
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• 2014

In this study, the sensor response and sensitivity is experimented and analyzed quantitatively by the line numbers of chlorine ion reaction type corrosion sensor that is developed. The sensor response of the developed corrosion sensor is verified with properties of chlorine ion. The multilineal sensor is shown a large resistance change more than the single line sensor by damage of the sensor. And, the resistance change of sensor is as large as high concentration of NaCl aqueous solution, the sensitivity of multilineal sensor is higher than single line sensor's, and the depth of sensor's location is as large as the increasing of resistance change time (cycle). These results suggest that, the developed corrosion sensor could sense corrosion reaction, sensor sensitivity and change of resistance for chloride ion. Especially, It was judged that 7 line sensor was the most superior for monitoring chloride ion immigration into concrete.

• Korean Journal of Construction Engineering and Management
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• v.8 no.5
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• pp.71-79
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• 2007

It is common that the analysis of VE/LCC is performed in design phase of quay wall structures. The analysis is mainly executed based on experience and engineering sense of expert considering the selection of construction method, construction and maintenance cost. Recently there are increasing demands on the analysis that includes uncertainty and vulnerability of input parameters, for this purpose, fuzzy reliability based probabilistic VE/LCC analysis model for quay wall structures is suggested. In VE/LCC analysis for quay wall structures, the application of probabilistic analysis method give very similar results compare with those of deterministic analysis method. It is anticipated that the methodology proposed in this paper can also be utilized in the design and maintenance phase of other facilities where decision making is made for the probabilistic life cycle cost and value analysis.

• Korean Journal of Heritage: History & Science
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• v.51 no.3
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• pp.88-103
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• 2018

The purpose of this study was to excavate the items of the comprehensive maintenance plan for scenic sites considering sustainability and analyze the needs of them. In this sense, based on 35 reports of the comprehensive maintenance plan established between 2006, when scenic sites started to be designated, and 2017, the items used in 'investigation field' and 'planning field' were examined, and then a survey regarding the needs of the items was conducted using a "5-point Likert Scale", targeting officials at 60 local governments in the whole country. Of 60 local governments, opinions from 48 officials at 45 local governments were analyzed. In order to verify the consistency of their opinions, "Reliability Analysis" was conducted, and Cronbach's alpha coefficient was 0.968 and 0.970 for 'investigation field' and 'planning field', respectively, showing high reliability. As a result of the survey, most opinions generally expressed the needs of 6 items of 'investigation field' of the comprehensive maintenance plan. Especially, the needs to investigate 'historical environment', 'natural environment', 'humanistic environment', and 'landscape' turned out to be high. In addition, as for 'general environment' and 'users', the needs of specific items such as 'distribution of main cultural properties and historic sites' (4.04) and 'acceptance of opinions from local residents and interested parties' (4.15) were found to be high. Besides, the items of 'planning field' also turned out to be needed in general (4.0). Particularly, the needs of 'enhancement of designated value and status' (4.26) and 'the comprehensive maintenance plan for designated areas of cultural properties and historic and cultural environment preservation areas' (4.25) in 'historical environment', 'maintenance of historic buildings at scenic sites' (4.28) in 'humanistic environment', and 'landscape trail planning' (4.28) in 'landscape' were found to be high. In conclusion, the practical items related to investigation and planning of the comprehensive maintenance plan for scenic sites are expected to contribute to effective conservation and management of scenic sites in the future.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.40 no.4
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• pp.15-31
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• 2022

This study interpreted the logical validity of the landscape restoration and maintenance patterns of Changgyeonggung Palace, where modern landscapes coexist. The results of the study are as follows; First, the changes in the landscape restoration and maintenance attitude concerning the Changgyeonggung management organization were identified. With the establishment of the Office of the Imperial Garden, an imperial property was nationalized. The Cultural Heritage Managing Department was opened in 1961, and Changgyeonggung Palace were preserved as designated as historical sites in 1963. An environmental purification was implemented by the Changgyeonggung Office as a follow-up measure for restoration in 1983. As the Cultural Heritage Administration promoted in 1999 and the Royal Palaces and Tombs Center was established in 2019, the palace has been managed professionally as a palace landscape to provide a viewing environment. Second, In the 'Purification Period of Changgyeongwon(1954~1977)', environmental purification was carried out to restore amusement facilities, install facilities for cherry blossom viewing, and develop the place into a national zoo. In the 'Reconstruction Period of Changgyeonggung(1983~1986)', restoring function as an urban park, reserving green areas, the outside space was recreated in the traditional feel, and the forest area was generally maintained. In the 'Supplementation Period of Traditional Landscape Architecture Space(1987~2009)', a uniform green landscape was created with pine trees and various vegetation landscapes centered on the flower beds. In the 'Improvement and Maintenance Period of Viewing Environment(2010~2022), a master plan was reestablished on the premise of utilization, but maintenance has been carried out in a small scale centering on unit space. Third, regarding the validity of the landscape restoration and maintenance, It was found in terms of 'originality' that the recovery of the palace system has not been expanded for over 40 years in existing areas. The 'characteristics of the times', which shows whether multi-layered history was taken into account, Changgyeongwon was excluded from the discussion in the process of setting the base year twice. In terms of 'integrity,' the area of the Grand Greenhouse where the historic states coexists needs a maintenance policy that binds the greenhouse, carpet flower bed, and Chundangji Pond. The 'utility' identified as the utilization of spaces suggests the establishment of a sense of place in the Grand Greenhouse area, which is concentrated with programs different from other areas.

• Current Research on Agriculture and Life Sciences
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• v.1
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• pp.113-140
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• 1983

This is a study on a landscape planning along the street 1~4, which are gateways to Taegu city and an important scenery. Therefore, emphasis was given to provide a bright, clean and beautiful first impression to visitors and citizens. The area is being developed for education and athletic park. Plans to construct a fountain, pergolas and a pond were set up to complement the active and passive facilities to the existing a athletic facilities in the area. Since D part in the area have alkali soil (pH 8.1), soil amendment is necessary for successful growth of trees and ground covers. When the area is filled or added with new soil for soil amendment, it will be important to use fresh soil which can support plant growth. It will be ideal to use ground covers and shrubs on the existing retaining walls along the street for keeping natural vegetation and slope stability instead of further cutting and reconstruction. It is not reasonable in technical and economic sense to remove rocks of the slope for planting trees. In order to harmonize plant color distribute, tall needle and broad leaf trees in the background as a screen, flowering trees were arranged in groups at front, and annuals were mass-planted along the footway. Natural-form-trees will be planted because they not only serve as a greenbelt but also are more economics in maintenance than formative trees.

• Biomaterials and Biomechanics in Bioengineering
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• v.2 no.4
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• pp.249-269
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• 2015

A problem faced by oil companies is the maintenance of the location register of pipelines that cross the surf zone, the regular survey of their location, and also their inspection. A survey of the state of art did not allow identifying operating systems capable of executing such tasks. Commercial technologies available on the market also do not address this problem and/or do not satisfy the presented requirements. A possible solution is to use robotic systems which have the ability to walk on the shore and in the surf zone, subject to existing currents and ripples, and being able to withstand these ambient conditions. In this sense, the authors propose the development of a spider crab biologically inspired robot to achieve those tasks. Based on these ideas, this work presents a biomechanical study of the spider crab, its modeling and simulation using the SimMechanics toolbox of Matlab/Simulink, which is the first phase of this more vast project. Results show a robot model that is moving in an "animal like" manner, the locomotion, the algorithm presented in this paper allows the crab to walk sideways, in the desired direction.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.443-446
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• 2002

In this paper, a phase difference of liveline insulator was measured and analyzed to estimate the contamination degree. The probability of accident rises according to the increase of the contamination. So the estimation of contamination degree is very important in design and maintenance of outdoor insulator. There are many methods to measure the contamination degree, but those methods use the spacial sense to measure the contamination degree. So, we have no information about the contamination from the liveline insulator, but there is a measurement of phase difference to estimate the contamination degree. The phase difference is varied with the increase of ESDD, so the contamination degree could be estimated by using those characteristics. The experiment is performed to analyze the interrelationship between contamination degree and phase difference. The variable condition is relative humidity that increases from 30 to 100 % in a chamber. We use the DAS program to measure and analyze the data. From the result, the variation of phase difference is different by the contamination degree, so we can confirm the possibility of estimating the contamination degree by the phase difference.

• Smart Structures and Systems
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• v.1 no.4
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• pp.355-368
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• 2005

Large and complex structures are being built now-a-days and, they are required to be functional even under extreme loading and environmental conditions. In order to meet the safety and maintenance demands, there is a need to build sensors integrated structural system, which can sense and provide necessary information about the structural response to complex loading and environment. Sophisticated tools have been developed for the design and construction of civil engineering structures. However, very little has been accomplished in the area of monitoring and rehabilitation. The employment of appropriate sensor is therefore crucial, and efforts must be directed towards non-destructive testing techniques that remain functional throughout the life of the structure. Fiber optic sensors are emerging as a superior non-destructive tool for evaluating the health of civil engineering structures. Flexibility, small in size and corrosion resistance of optical fibers allow them to be directly embedded in concrete structures. The inherent advantages of fiber optic sensors over conventional sensors include high resolution, ability to work in difficult environment, immunity from electromagnetic interference, large band width of signal, low noise and high sensitivity. This paper brings out the potential and current status of technology of fiber optic sensors for civil engineering applications. The importance of employing fiber optic sensors for health monitoring of civil engineering structures has been highlighted. Details of laboratory studies carried out on fiber optic strain sensors to assess their suitability for civil engineering applications are also covered.

• Journal of the Korean housing association
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• v.22 no.3
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• pp.47-57
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• 2011

The purpose of this research consists in the process analysis and studying of the Residents-Participated Workshop which aims to improve the environment of common areas at the rental apartments, and also to present the spacial designs for the improved environment. The objects of this research are Susojugong Rental Apartments and total 3 Residents-Participated Workshops were held. The contents of the research are as follows; 1) Background and purposes of resident environmental improvement and associated group of people were examined. 2) Execution of Residents-Participated Workshop programs and the analysis of the process to present the plans of environmental improvement. The results of the research are; 1) representing variety of opinions and the increased sense of participation. 2) possibility of presenting designs initiated by residents through participatory design workshop. 3) improvement of relationships between managerial authorities, specialists and residents. 4) the place of interchange among residents. 5) necessity of assisting workshop tool, Resident-Participated Workshop programs and schedules. Environmentally improved designs which were presented at the workshop have been actually demonstrated at the Rental Apartments of this research. Follow up research on the process of construction, maintenance management of the construction after completion and the full contents should be studied further.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.12
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• pp.2046-2052
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• 2016

Ramp metering is one of the most efficient and widely used control methods for an intelligent transportation management system on a freeway. Its objective is to control and upgrade freeway traffic by regulating the number of vehicles entering the freeway entrance ramp, in such a way that not only the alleviation of the congestion but also the smoothing of the traffic flow around the desired density level can be achieved for the maintenance of the maximum mainline throughput. When the cycle of the signal detection is larger than that of the system process, the density tracking problem needs to be considered in the form of the discrete-time system. Therefore, a discrete-time sliding mode control method is proposed for the ramp metering problem in the presence of both input constraint in the on-ramp and exogenous disturbance in the off-ramp considering the random behavior of the driver. Simulations were performed using a validated second-order macroscopic traffic flow model in Matlab environment and the simulation results indicate that proposed control method can achieve better performance than previously well-known ALINEA strategy in the sense that mainstream flow throughput is maximized and congestion is alleviated even in the presence of input constraint and exogenous disturbance.