• International Journal of Highway Engineering
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• v.17 no.3
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• pp.1-12
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• 2015

PURPOSES : This paper presents a description of the current issues facing road managers regarding the surface-type conversion of low-volume roads for cost savings. METHODS: The paper reviews previous works conducted toward this end, acknowledges gaps in the current research, and lays out what information is needed for further studies. RESULTS : If the cost to maintain an unsurfaced road is less than the cost of maintaining a surfaced road, then there is potential for cost savings for the management agency. However, the problem is bigger than simply maintaining the roads that already exist. If unsurfaced roads prove to be more economical than surfaced roads, then the cost to convert from a surfaced to an unsurfaced roadway, and vice versa, when necessary, must also be examined. CONCLUSIONS : No other studies have addressed the un-surfacing of a road for cost savings, and it is therefore unknown whether substantial savings can be realistically obtained by converting from a surfaced to an unsurfaced road. To determine whether a conversion policy would be a viable option, additional data and research are needed.

• Journal of the Semiconductor & Display Technology
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• v.18 no.4
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• pp.87-91
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• 2019

The diagnosis of the failure for the existing electrical facilities was based on regular preventive maintenance, but this preventive maintenance was limited in preventing a lot of cost loss and sudden system failure. To overcome these shortcomings, fault prediction and diagnostic techniques are critical to increasing system reliability by monitoring electrical installations in real time and detecting abnormal conditions in the facility early. As the performance and quality deterioration problem occurs frequently due to the increase in the number of users of the motor pump, the purpose is to build an intelligent control system that can control the motor pump to maximize the performance and to improve the quality and reliability. To this end, a vibration sensor, temperature sensor, pressure sensor, and low water level sensor are used to detect vibrations, temperatures, pressures, and low water levels that can occur in the motor pump, and to build a system that can identify and diagnose information to users in real time.

• Journal of the Korea Safety Management & Science
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• v.26 no.2
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• pp.43-53
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• 2024

This study analyzes the importance-performance analysis (IPA) of the 10 dimensions of the smart construction safety management system, and analyzes which dimensions are important and which dimensions are performing to determine key improvement tasks, incremental improvement tasks, Maintenance and reinforcement tasks and continuous maintenance tasks were derived. Among the 10 dimensions of the smart construction safety management system, the dimensions that are recognized as important by all field managers and field workers and have high performance are the automatic risk displacement measurement system, smart environmental sensor system, and heavy equipment seizure prevention system. However, areas that were perceived as having high importance but low performance were worker location tracking systems, smart safety helmet chin muscles, and smart safety ring fastening. Among the smart construction safety management systems perceived by field managers, areas for key improvement with high importance and low performance included worker location tracking system and smart safety ring fastening. Among the smart construction safety management systems perceived by field workers, the area for key improvement with high importance and low performance was the automatic risk displacement measurement system.

• Journal of the Korean housing association
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• v.4 no.2
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• pp.33-43
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• 1993

The purpose of this study is to support satisfaction for reasonable management method to elevate the enhancement of management attitude and the satisfaction of management state for Multi-family Housing. This study was intended to find out variables which influence on the satifaction and attitude of resident to the management of Apartment, and to investigate variables influencing on the satisfaction and attitude of resident to the management of Apartment. In this study, survey research method is employed. The sample is taken from 336 APT. resident's living in Seoul, from 13th of Sep. to 20th of Sep, in 1993. Used statistica] method are Frequency, Percentage, 1-test, One-way Anova, Duncan-test, Multip]e Regression. The major finding were as follows: 1) The work of management of Multi-family Housing was classified into three type ; a)administration management b) maintenance management c) community-life control. 2) The management attitude of Apartment inhabitant is very high, especially .the attitude of maintenance management is the higest. But they disagree with the raise of management cost necessary to maintenance management. 3) The satisfaction of administration management, maintenance management, community-life control management is all low in the management condition of Apartment.'1'he management method of present Apartment shows a little problem.

• KIEAE Journal
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• v.10 no.5
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• pp.171-179
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• 2010

Korea owns vast amount of apartment houses no less than those of world prominent countries, but did not pay enough efforts to maintain existing apartment houses and develop policies to reuse them due to growth driven policy of housing supply like construction of new houses. Korea constructed tremendous amount of houses in short period through government led forced house supplying policy, and resulted in excess houses such that present house supply rate happened to be reaching 110%. However, recently there are growing demand of change in housing policy due to social environmental changes like low birth rate and aging of society etc and nationals' demand for improvement of residential quality. When such social changes are demanded and 80% of apartment houses in Korea are less than 20 years old, renovations and remodeling of apartment houses are anticipated to emerge as important matter. In particular, the apartment houses in Seoul and the 1st generation new cities like Bundang and Ilsan etc have passed considerable period of time after construction and require safety measure, it is quite impending to loan programs for the maintenance of existing apartment houses. The objective of this study is to compare and analyze the system of loan programs about apartment houses of Japan, and then to propose to accelerate loan programs about maintenance for apartment houses in korea.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.10
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• pp.58-66
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• 2010

This paper shows an implementation and management result of wireless networks based security light control system, which performs a great role in protection of pedestrians and prevention of crime. Conventional security light units have severe limits in confirmation and inspection of security light unit failure, like wilful damage by someone or failure by influence of other equipment or failure by spontaneous heat-increase, and so on. In addition, local government offices are responsible for maintenance of security light units and as a matter of fact, most of civil complaints are about security light units. It is an obvious that the existing security light maintenance system reaches the limit and the security light maintenance problem is a difficulty of local government. Therefore, efficient security light control system is needed, which enables central control and intelligent maintenance. Moreover, the system has to be easy to control and has to be stable. In this study, wireless sensor network based security light control system is implemented, which is independent of programming language and platform, and which is simple to control and extend the system. The proven protocols, HTTP and SOAP, are utilized in order to improve the system reliability. This paper shows the excellence of our proposed system by implementing and operating it in real environment.

• The Journal of Korea Robotics Society
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• v.17 no.2
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• pp.238-244
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• 2022

Maintenance works of offshore wind turbines could take a longer time, which causes the reduction of their energy production efficiency, than those of onshore wind turbines owing to severe offshore environment. Subsequently, preventive maintenance measures are required to increase the production efficiency. Thus, we proposed a wheel-based Underwater Pole Climbing Robot (UPCR) platform, which was aimed at the periodic inspection and maintenance of the substructures of the offshore wind turbines, with three advantages: high speed, good mobility and low power consumption. In the proposed platform, a self-locking system using a gripper module was adopted for preventing slippery problem and a dual configuration was chosen for moving on a branched structure. As a result, the proposed robot was able to continuously climb, preserve it's position at the pole without consuming energy, and move from the pole to the other branched pole. The results of this research show that the UPCR has basic moving capabilities required for the underwater work for the substructures of the offshore wind turbines.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.6
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• pp.95-104
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• 2006

The presence of cavitations under pavements or behind tunnel linings of concrete is likely to result in collapse. One method of detecting such voids by non-destructive means is low frequency type radar(GPR). By the way, the size and thickness of small cavitation can't be detected by the present radar technology with low frequency and low resolution when it apply to civil structures like that. To overcome these problems and limitations, this study aims to develope and propose a new analysis method for estimating the depth, cross-sectional size and thickness of cavitations using low frequency radar. A new proposed method is based on the experiments that are carried out for analyzing the correlation between the measurement values(the amplitudes of radar return) of low frequency radar and various type of cavitations. In this process, the threshold value for radar image processing which aims to represent only cavitations to be fitted size can be obtained. As the results, it is clarified that a proposed method has a possibility of estimating cavitation depth, size and thickness with good accuracy in laboratory scale.

• Journal of Wetlands Research
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• v.15 no.3
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• pp.317-328
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• 2013

The aim of this study is to compare the effects of the maintenance water supply methods on the ecological restoration of 5 urban streams such as Mugeo cheon, Yaksa cheon, Yeocheon cheon, Myeongjeong cheon and Cheokgwa cheon in Ulsan metropolitan city. Water quality of the streams have been innovatively improved and the ecosystems have gradually been restored by supplying maintenance water constantly. However, we found that if the maintenance water was in a state of higher salinity or low quality, even enough supply was not helpful and even harmful for ecological restoration. We confirmed that the most important things to create or maintain from the urban stream to the ecological stream are that facilities like a walkway construction should be installed at least, supplying appropriate maintenance water, and a connection with the main stream.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.46 no.2
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• pp.47-56
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• 2023

This study identified the core competencies of aircraft maintenance quality engineers and compared the importance and retention of core competencies. Through literature research, 21 core competencies were derived in three areas of management technology, elemenal technology and collaboration technology, and a survey was conducted on the importance and retention of core competencies for 42 aircraft maintenance quality engineers. As a result of the survey, the importance of all core competencies of aircraft maintenance quality engineers is 3.95/5 on average, and the retention of all core competencies is 3.99/5 on average. 'Risk Management', 'Creating Document', 'Honesty/Moral' were identified as the most important competencies in each area, and 'Quality Management', 'Language', 'Honesty/Moral' were identified as the most possessed competencies in each area. An IPA (Importance-Performance Analysis) was performed to analyze the details. Through IPA, 'Risk Management' and 'Safety Management' were evaluated as having a low degree of retention compared to a high level of importance. Therefore, they were identified as a core competencies that need to be improved first. In addition, the characteristics of each core competency and the recognition level in the field were also identified. This study will be helpful in defining the roles and functions of aircraft maintenance quality engineers to improve flight quality and prevent aviation accidents.