• Proceedings of the Acoustical Society of Korea Conference
• /
• autumn
• /
• pp.367-370
• /
• 2001

Various shapes of the noise barrier frame and construction of the sound absorbing panels are studied. It is found that insertion of the sound absorbing panel into barrier frame results in the decrease of the sound absorption coefficient, while the empty frame shows a peak around 250Hz. Using double sound absorbing panels with air gap can increase sound absorption coefficient up to NRC 0.85.

• Journal of the Korean Society of Safety
• /
• v.12 no.2
• /
• pp.119-132
• /
• 1997

According to the construction environmental changes due to the trend of large scale and complicated building construction, many construction methods(such as : TOPDOWN )are more often used. However, it is pointed out that occupational pulmonary diseases, reduction of the machinery lifetime and productivity caused to be narrow visual field and collision between the workers. Therefore, this study is mainly dealing with the views of productivity and safety improvement in order to improve work efficiency and to insure the safety in underground construction environment.

• International conference on construction engineering and project management
• /
• 2009.05a
• /
• pp.230-236
• /
• 2009

Double-front construction machinery, which was designed for complicated tasks, requires intelligent systems that can provide the quantitative work analysis needed to determine effective work procedures and that can provide operational and cognitive support for operators. Construction work environments are extremely complicated, however, and this makes state identification difficult. We therefore defined primitive static states (PSS) that are determined using on-off data for the lever inputs and manipulator loads for each part of the grapple and front and that are completely independent of the various environmental conditions and operator skill levels. To confirm the usefulness of PSS, we performed experiments with a demolition task by using our virtual reality simulator. We confirmed that PSS could robustly and accurately identify the work states and that untrained skills could be easily inferred from the PSS-based work analysis. We also confirmed in skill-training experiments that advice information using PSS-based skill analysis greatly improved work performance. We thus confirmed that PSS can adequately identify work states and are useful for work analysis and skill improvement.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.20 no.12
• /
• pp.44-53
• /
• 2021

As environmental issues have emerged worldwide, emission gas regulations have been strengthened. In the construction machinery sector, studies have been actively conducted to utilize the power source of electric motors owing to the increasing demand for zero emissions. In this study, the gear specifications of an electric axle for construction machinery were selected by considering the specifications of the motor, gear tooth contact pattern, and face load factor. The gear strength evaluation was performed at the system level using the simulation model. The bending and contact strength of the spiral bevel gears and the bending strength of the planetary gear set showed a safety factor of 1 or more. However, the contact strength of the planetary gear set showed a safety factor of 0.92. Conservative results were derived by performing the analysis under the rated load condition of the motor. However, the ratio of the equivalent torque to the rated torque of the motor was 45% or less, hence, it was determined that no difficulties should arise regarding the durability of the axle.

• Korean Journal of Construction Engineering and Management
• /
• v.17 no.6
• /
• pp.13-23
• /
• 2016

Construction automation based on information and communication technology(ICT) has been studied for improving productivity in the construction industry. This study investigates domestic research trends in ICT-based construction automation using text mining techniques. The results show that 'Technology to collect and analyze project progress(26%)' and 'Technology to analyze and apply the automation element of construction machinery(28%)' are the major research area. The word of 'construction information' is showed as important keywords in the area of 'Technology to collect and analyze project progress', and researches focusing on resource management, site management, information management, and real-time information monitoring have been mainly conducted. The word of 'ubiquitous' is shown as important keywords in the area of 'Technology to analyze and apply the automation element of construction machinery', and researches focusing on ubiquitous information management, ubiquitous site management, and measurement system have been mainly conducted.

• Korean Journal of Construction Engineering and Management
• /
• v.23 no.6
• /
• pp.21-29
• /
• 2022

Productivity estimation of construction operations is crucial to successful project delivery. Especially in the preconstruction phase, the adequacy and effectiveness of plans directly affect the actual performance of operations. Currently, productivity estimation is conducted by referring to existing references such as the Construction Standard Production Rate. However, it is difficult to promptly apply changing conditions of operations when using such references. Moreover, it is difficult to deduce the optimal combination of construction machinery for the given condition. This paper presents a simple simulation model that can be used to generate productivity data that considers site conditions and construction equipment combination. The suggested method is expected to be used as a decision making assisting tool for practitioners who rely on estimations using the Construction Standard Production Rate when establishing construction plans using heavy machinery such as backhoes, loaders and dumptrucks.

• Journal of Applied Reliability
• /
• v.11 no.3
• /
• pp.235-244
• /
• 2011

Hydraulic hose assemblies deliver a fluid power in various oil pressure equipment such as construction machinery, automobile, aircraft, industrial machinery, machine tools and machinery for ships. Also, they are widely used as pipes in oil pressure circuit. When we estimate their lifetime, it is essential to conduct an accelerated life test by choosing the factor that suits the usage condition of the test object since traditional test method for estimating lifetime under the influence of various external factors incurs hardship in terms of time and expenses. The objective of this study is to propose an acceleration model that takes both temperature and pressure without flexing condition into consideration. The lifetime is estimated by applying the proposed temperature-nonthermal acceleration model to the test data. And we compare the proposed temperature-nonthermal acceleration model and the accelerated life equation suggested by John(1994).

• Journal of Drive and Control
• /
• v.4 no.4
• /
• pp.78-83
• /
• 2007

• Proceedings of the Korean Nuclear Society Conference
• /
• 2005.10a
• /
• pp.711-712
• /
• 2005

• Korean Journal of Construction Engineering and Management
• /
• v.21 no.1
• /
• pp.87-98
• /
• 2020

As the construction industry accounts for 28.5% of industrial accidents in Korea and 29.6% of industrial accident deaths in 2017, it is necessary to search for a priority disaster reduction scheme for the construction industry in order to reduce the industrial accident rate. Therefore, this research suggested improvement direction for construction accidents reduction based on factors affecting construction accidents occurring in the construction site by DEMATEL analysis. As a result of the analysis, the 4M factors with the highest Prominence and Relation is 'Management', and the detailed analysis of the 4M factors were Personal characteristics of workers, Defects such as machinery and equipment, Inadequate inspection of machinery and equipment, Insufficient safety management plan, Inappropriate work orders from supervisors and field managers. The analysis results of this research can be used as a basic data for establishing direction of reduction and improvement of construction accidents.