• Tunnel and Underground Space
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• v.9 no.2
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• pp.131-140
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• 1999

Although there have been lots of geological or geotechnical surveys for construction sites, most of data obtained from these surveys have not been reused properly for the future construction work due to the absence of systematic management of data management system. This research, therefore, has focused on the development of DB system, Rockmass Information Management System(RIMS), to save, manage and reuse these abandoned data, specially test data of rock and rockmass with site conditions. RIMS has not only the basic functions of inputting, modifying, and dynamic searching of data but also several data control modules which can manage, input and correct, analyse and report data. Furthermore it saves data such as strata status, laboratory test results, in-site test results, and so on using 3-dimensional data stacking up structure. It is using x, y coordinates to represent horizontal positions and depth to represent vertical position of data. With the development of RIMS, this research has analyzed and classified present conditions of data in RIMS according to region, rock type, etc.

• Journal of Drive and Control
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• v.17 no.3
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• pp.9-14
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• 2020

A special purpose machine with two manipulators and quadruped crawler system is being developed to work at disaster sites where it is intended to quickly respond in the initial stages after the event. In this study, a terrain recognition module is developed so that the above special purpose machine can quickly obtain ground information to help choose its path while recognizing objects in its way, this is intended to enhance the remote driver's limited situational awareness. Terrain recognition modules were developed for two tasks (real-time path guidance, precision terrain measurements). The real-time path guidance analyzes terrain and obstacles while moving, while the precision terrain measurement feature provides more accurate terrain information by precisely measuring the ground in front of the vehicle while stationary. In this study, an air-cooled sensor protection module was developed so that the terrain recognition module can continue its vital tasks in the event of exposure to foreign substances, including scattered dust, mist and rainfall, as well as high temperatures.

• Journal of Drive and Control
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• v.17 no.3
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• pp.1-8
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• 2020

Recently, a special purpose machine with two manipulators and quadruped crawler system has been developed for rapid life-saving and initial restoration work at disaster sites. This special purpose machine provides the driver with various environmental recognition functions for accurate and rapid task determination. In particular, the human detection technology assists the driver in poor working conditions such as low-light, dust, water vapor, fog, rain, etc. to prevent secondary human accidents when moving and working. In this study, a human detection module is developed to be mounted on a special purpose machine. A thermal sensor and CCD camera were used to detect victims and nearby workers in response to the difficult environmental conditions present at disaster sites. The performance of various AI-based life detection algorithm were verified and then applied to the task of detecting various objects with different postures and exposure conditions. In addition, image visibility improvement technology was applied to further improve the accuracy of human detection.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.3
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• pp.20-27
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• 2014

In the construction site, various earth retaining systems are developed and applied to maintain stability of excavated area and structures. Among the methods, the underground continuous wall and the column-type diaphragm wall methods are especially used in construction site nearby buildings or roads. However, these methods have some disadvantages such as the difficulty of quality control and long curing time because these methods need to cast fresh concrete at the construction site. In addition, these methods are usually applied to the site for the temporary purpose. In this paper, we suggest precast hollow prestressed concrete pile for continuous pile wall system. To investigate the structural behavior of suggested pile, which is the main member of the suggested system, tests pertaining to the structural behavior and prestressing force applied in the pile are conducted. From the test results, it was found that the prestressing force measured is sufficient compared with the value obtained by the design equation and the cracking moment measured is 34% higher than the design value. In addition to the above, this precast hollow prestressed concrete pile has an additional safety margin that the maximum moment is 59.2% higher than the cracking moment which is one of the serviceability limits for the design of the system.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2004.11a
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• pp.625-628
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• 2004

Even though the tower crane is a major equipment in a construction of high rise buildings, there are lack of studies of it. This study is presenting a framework of developing a intelligent tower crane applied with the technology of machine-vision, RFID(Radio Frequency Identification), or GPS(Global positioning System) and proposing the prototype of machine-vision module, sub module of this Framework. Through monitoring form CCTV(Closed Circuit Television) and LCD(Liquid Crystal Display) in machine-module the real time communication between in-site workers and crane operator is possible. this will improve the productivity and safety of the tower crane.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.1173-1176
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• 2007

The breaker noise is one of the main noise sources of construction site. It is very important to assess and measure the breaker noise accurately, because the noise labelling will be in effect January 2008 in Korea. Therefore, It is necessary to measure the sound power level of breakers and use a appropriate test method in accordance with international standard. In this study, we measure the sound power level of breakers by using the breaker noise measurement system. This system makes it possible to measure the breaker noise more accurately than to measure the noise of that attached with excavator, because this system can control main factors affecting breaker noise such as hydraulic input power, hydraulic supply pressure, breaker inlet oil flow and so on.

• Proceedings of the KAIS Fall Conference
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• 2003.11a
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• pp.211-215
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• 2003

Network security should be first considered in a distributed computing environment with frequent information interchange through internet. Clear classification is needed for information users should protect and for information open outside. Basically proper encrypted database system should be constructed for information security, and security policy should be planned for each site. This paper describes access control, user authentication, and User Security and Encryption technology for the construction of database security system from network users. We propose model of network encrypted database security system for combining these elements through the analysis of operational and technological elements. Systematic combination of operational and technological elements with proposed model can construct encrypted database security system secured from unauthorized users in distributed computing environment.

• Journal of the Korean Society of Safety
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• v.32 no.4
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• pp.59-65
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• 2017

This study examined the stakeholder cognition of the safety certification marking system by surveying manufacturers, lessors, and users. In addition, among various issues about safety certification marking systems, the improvement of safety certification marking contents was suggested in order to guarantee quality of temporary equipments. The results by statistical method show that it is necessary to increase of users' understanding about the safety certification marking system. In addition, the quality management system of temporary equipments should be introduced to control the actual condition that temporary equipments of various product companies are mixed in a site during removal and reuse processes. For detailed marking contents, it is recommended that a certification mark, an identification number, and the production year should be displayed and the manufacturer name could be selectively presented. Detail informations such as a safety certification number, a product company, a model type or name, a specification, a weight, a product number, and the location of a certification mark should be identified by the identification number.

• International Journal of Highway Engineering
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• v.15 no.2
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• pp.19-27
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• 2013

PURPOSES : This study aims to investigate the snow-melt effects of an underground electric heater's snow-melt system via a field performance test, for evaluating the suitability of the system for use on a concrete pavement. The study also investigates the effectiveness of dynamic measures for clearing snow after snowfall events. METHODS : In order to check the field applicability, in November 2010, specimens were prepared from materials used for constructing concrete pavements, and underground electric heating meshes (HOT-mesh) were buried at depths of 50 mm and 100 mm at the site of the Incheon International Airport Construction Research Institute. Further, an automatic heating control system, including a motion sensor and pavement-temperature-controlled sensor, were installed at the site; the former sensor was intended for determining snow-melt effects of the heating control system for different snowfall intensities. Pavement snow-melt effects on snowy days from December 2010 to January 2011 were examined by managing the electric heating meshes and the heating control system. In addition, data on pavement temperature changes resulting from the use of the heating meshes and heating control system and on the dependence of the correlation between the outdoor air temperature and the time taken for the required temperature rise on the depth of the heating meshes were collected and analyzed. RESULTS : The effects of the heating control system's preheat temperature and the hot meshes buried at depths of 50 mm and 100 mm on the melting of snow for snowfalls of different intensities have been verified. From the study of the time taken for the specimen's surface temperature to increase from the preheat temperature ($0^{\circ}C$) to the reference temperature ($5{\sim}8^{\circ}C$) for different snowfall intensities, the correlation between the burial depth and outdoor air temperature has been determined to be as follows: Time=15.10+1.141Depth-6.465Temp CONCLUSIONS : The following measures are suggested. For the effective use of the electric heating mesh, it should be located under a slab it may be put to practical use by positioning it under a slab. From the management aspect, the heating control system should be adjusted according to weather conditions, that is, the snowfall intensity.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.11a
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• pp.241-242
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• 2019

This technology is a water leak repair technology using composite materials of concrete structures that block leakage of structures by injecting rapid microcement into the face of underground concrete to block water and injecting flexible glycidylacrylate. Rapid micro cement system repair materials are mixed with fine fibers to improve the flexural sensitivity of the material and to form a layer that blocks stabilized water at the back of the structure by allowing rapid and tight spatial filling during injection with high cohesion The glycidylacrylate repair material can control the expansion rate, and the external stress also has the characteristic that the form of the material is not destroyed or separated, which can also be applied to vibrating induced structures that produce repetitive fatigue loads, and has an effective durability in saline, alkali, acid (chloric acid, sulfuric acid, nitric acid).