• The Journal of the Convergence on Culture Technology
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• v.5 no.3
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• pp.191-195
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• 2019

South Korea is in a dangerous situation where a war between the two Koreas could be triggered at any time based on the MDL (Military Demarcation Line) between the two Koreas due to the inter-Korean standoff over the armistice. Also, unlike the borders of other countries, the border between the two Koreas is the front-line area where people can feel the threat of life that could be triggered by war. Soldiers who work in special areas such as the contact area are not easily accessible due to local conditions, and are less likely to go out, stay out, stay out, or visit, and the working environment is overloaded with vast forests and silence at night, and feel anxious, lonely and insecure because they don't know when any situation will occur near the enemy. Therefore, a great deal of help will be needed to pay attention to soldiers who give up their lives here and perform their national defense duties, and to finish their barracks life safely and faithfully, and support for psychological adaptation of service members in the border areas.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.35 no.9
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• pp.143-150
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• 2019

The purpose of this study was to propose how to determine the setting time related to the determination of the surface finish working time of the concrete using a Durometer, which is used as a rubber hardness meter. Two different types of Durometer were used to measure the setting time of the concrete. High flowing concrete with 40% of water to binder ratio was fabricated maintaining $600{\pm}100mm$ of slump flow. The test results indicated that the application of the Durometer resulted in a high correlation with the penetration resistance tester in both mortar and concrete. When measuring the setting time of the concrete, with properly used with Durometer, evaluation of the setting time of the concrete can be available. Therefore, it is thought that the measurement of the final set of the durometer C type can be useful to decide the limit time of the finishing operation and the time of the rejuvenation of the curing process by measuring the finishing set at 40 HD in the case of the initial set and 10 HD in the case of D type.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.6 no.1
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• pp.1-16
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• 1996

This study was conducted at an automobile assembly line located in Kyonggi-do, Korea from January 16 to February 28, 1995. The purposes of this study were to assess worker exposures to hand-arm vibration and the performance of gloves for reduction of vibration. The exposure to vibration was measured using to the ISO 5349(1986) method. Vibration acceleration and frequency spectra for each tool were determined on-line replicating actual working conditions and analyzed together with exposure time for evaluating individual worker exposure. Eight pneumatic hand tools, 60 workers exposured to hand-arm vibration, and three pairs of gloves were involved in this study. Results are summarized as follows. 1. Dominant frequencies of vibration for all tools(n=8) measured in this study ranged from 250 Hz to 800 Hz. 2. There was no significant correleration between dominant frequencies and free running speed (p>0.05). 3. Total predicted exposure times of using impact, hammer type did not exceed 40 minutes, but metal finish task, using grinder and sander exceeded 40 minutes. Total exposure time affected significantly the frequency-weighted, 4 hr equivalent acceleration. 4. Predicted prevalence and observed exposure period data were compared in workers(n=60), according to ISO 5349. In this results, 23(50.0 %) and 24(48.07 %) persons exceeded the mean latency periods for vibration-induced white finger(VWF) at 10 % (n=46) and 50 % (n=52) standards, respectively. On the basis of ISO equation, mean latent periods for VWF were 3.23, 4.72 years at 10 %, 50 % standards, respectively. 5. Reduction of vibration by gloves was evaluated. Since impact pneumatic tools produced low frequency vibrations, conventional gloves did not provide any protection. Gloves A and C amplify somewhat the signal at frequency below 400 Hz; the attenuation increases progressively by frequency to reach 18 dB ($7.94{\times}10^{-6}m/s^2$) at 1,000 Hz, slightly worsening Glove B did not provide any protection and made the situation slightly worse. However, since they make the hands warm, the occurrence of vibration-induced white fingers may be reduced.

• Korean Journal of Construction Engineering and Management
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• v.24 no.2
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• pp.13-23
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• 2023

Unlike building construction projects, where the activity is repeatedly carried out in a limited area, civil engineering projects such as roads and railroads are carried out in a linear type in a horizontal working space over several tens of kilometers. Each activity is managed with a station number that has a unit of distance from the starting point to the end point. For this reason, since the work location information of the activity is a major management factor, the Gantt chart system that expresses only schedule information may have limitations. In this study, authors propose a method for constructing a linear schedule chart that can simultaneously express schedule information indicating the start and finish dates and location information indicating the start and end positions of each activity, and develop a system for generating a linear schedule chart. In the study, the coordinate axes of the linear schedule chart consisted of distance and date values on the X and Y axes, respectively, and each activity was expressed as a symbol that can infer the type of work to increase the visibility of the linear schedule chart compared to the simple bar chart method. The linear schedule chart generation system was reviewed for practical applicability by utilizing the actual schedule data of bridge structures in a railroad project.