• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.6
• /
• pp.61-69
• /
• 2016

Since 2000, the market of convenient stores in Korea has developed rapidly due to the explosive growth in single households but it still consists mainly of manual work due to the nature of the domestic industry. Hence the explosive increase in demand in the market is mostly due to workers. Therefore, the research aimed at encouraging efficiency via automation, which is carried out in manufacturing, such as electronic, cars and so on, is inadequate. This study performed a feasibility analysis of investment for introducing an automated system on brand A, which is domestic famous convenience store company. Productivity growth according to the introduction of an automated guided vehicle and the cost-benefits was studied with using a simulation for the picking process, which is most personnel and time consuming. As a result, the simulation showed that the equipment AGV introduced for choosing the process has the effects of cost saving and increased time efficiency for performing manual labor. Furthermore, appropriate numbers of AGV were forecasted considering the capacity of the distribution Center in the brand A convenient store, which has been growing steadily. There are increasing numbers of worker labor costs in the distribution industry these days. Before building a large new automate center, it is expected to provide a good information to investors who are considering increasing productivity through partial automation of each of unit process to achieve some cost reduction.

• Journal of the Korea Concrete Institute
• /
• v.26 no.3
• /
• pp.385-392
• /
• 2014

Reshoring makes slab deflect and support its own weight. The construction loads on the slabs in lower levels decrease using the reshoring. Simplified analysis proposed by ACI 347.2R-05 showed that if the reshoring is applied, construction loads on slabs and shores, and quantities of forms and shores decreased by 40%, 23%, 40%, and 50%, respectively. Shores' loads were comparatively measured on site. The measured reshore load was half of the load before removing the shores and was also lower than the measured shore load by 35%. To verify the safety of the reshoring, deflections of beams and strains of beam longitudinal bars were also measured. The maximum deflection was only L/5000 and the maximum bar strain was only 3.6% of the yield strain. Consequently, reshoring neither cause problems on the safety nor serviceability. In addition, the beam load was expected from the measured shores' loads and it coincides well with the predicted value by the simplified analysis of ACI 347.2R-05.

• Journal of Information Technology and Architecture
• /
• v.11 no.3
• /
• pp.359-369
• /
• 2014

This paper aims to analyze the change of dominion in Russian automotive market and Korea port to export cars to the Russia. First, we provide the current market structure and growth potentials of Russian automotive industry by using literature reviews and data survey. Next, we analyze the current situation to export cars through the Korean seaports using the BCG (Boston Consulting Group)'s matrix method. The analysis shows that the Russian car market has growth potential. The result of expectation of Russian major car export's port within 3~5 years since the year 2013 shows that the Pohang Port will maintain current market share because it has higher market share and growth potential. On the contrary, the Guangyang Port, Busan Port, and Ulsan Port will lose the market share because of the low growth potential. Also, the Incheon Port will become the cash cow market because it has more than 10 percent market share and higher growth potential. To increase the car export volume of ports to Russian market, this paper proposes that we should provide a differentiated service to Russian port based on the analysis of domestic or foreign car export logistics structure and flow. For further study, EA-based framework should be applied for efficient and effective policies.

• Journal of the Korea Institute of Building Construction
• /
• v.20 no.4
• /
• pp.357-365
• /
• 2020

While numbers of apartment housing are continually rising in the domestic housing construction industry, apartment contractors are currently developing plane models, upgrading facilities, and relevant technology, and investing much efforts to meet the higher demands of consumers. However, the construction process of apartment housing involves the intricate properties of the construction industry such as materials, workforce, equipment, weather, and unpredictable situations. If any of these factors becomes discordant and results in interference and interruption of the construction process, then defects, both functional and aesthetic, are likely to occur due to errors in the plan of industry organizers and constructors. Therefore, this research identifies the types of defects in an apartment construction project and analyzes their relative importance. Firstly, this research reviews the previous research trends and will reduce the needs of this research. Afterward, defect repair costs corresponding to the different defect types are calculated by applying results of the research and performing frequency analysis on defect types included in 'Tenant preliminary research' on apartments constructed by Company A. As a result of analyzing the importance of defect type, the top six activities, including tile, floor, paper hanging, PL window, cabinetry, and kitchen cabinet, are found to be of high importance, and the top six activities in question need of repair and management of defects first. The results of this study will help establish a plan to initially respond to such problems as refusal to move in and filing a defect suit against delay in repairing defects.

• Journal of the Korea Institute of Building Construction
• /
• v.10 no.1
• /
• pp.57-63
• /
• 2010

The bearing wall apartments which occupy the majority of multi-residential apartment buildings built in Korea, are known for having limited architectural plan flexibility, posing challenges in terms of maintenance and remodeling. The economic losses and environmental issues resulting from the reconstruction of bearing wall apartments are now accumulating to the extent that they are becoming a national concern. Multi-residential apartment buildings, which are now the dominant form of residence in Korea, must accommodate diverse customer needs and changes in life style. A new concept of Rahmen structure with architectural flexibility is Green Frame. GF multi-residence housing is expected to reduce construction costs and shorten the construction schedule by overcoming the shortcomings of conventional bearing wall apartments. This goal is consistent with the national policies that target the reduction of resource and energy consumption. In addition, GF will be established as a core contributor to achieving a reduction in $CO_2$ emissions, which will enable the sustainable growth of domestic construction industry, and address the low-carbon green growth drive implemented by the government.

• Korean Journal of Construction Engineering and Management
• /
• v.20 no.6
• /
• pp.89-97
• /
• 2019

Recently, BIM has been actively introduced in construction projects. In particular, the introduction of BIM in cost estimating process is expected to improve the accuracy and efficiency of the cost estimate. However, the quantity calculation and BoQ documents preparation process still require manual work. Although the BIM model may support quantification process, it is still problematic that the level of detail of the model must be very detailed to meet the items in BoQ. To address this, it is necessary to analyse the LOD criteria and to analyze the extent to which quantity can be computed according to the level of detail in the BIM model. For the analysis of LOD-based work items, the work item grades were divided into A,B, and C. In this study, the ratio and cost of each item that can be calculated at the LOD level in the detailed design phase are reviewed for each type of work, and the method for improving the quantity calculation using BIM is proposed. In the LOD 300 stage(Detailed design stage), the largest number of items in the class B, the major improvement class, are window and glass work. In addition, the most expensive type of work was analyzed by reinforced concrete work. In the future, it is necessary to suggest appropriate improvement way for items with high item ratios and items with high cost ratios. The results of this study are expected to be used as a BIM-based cost estimation or as basic data for improving the current BoQ system.

• Journal of the Korean Geotechnical Society
• /
• v.37 no.10
• /
• pp.77-87
• /
• 2021

Several studies have been conducted to analyze, predict, and prevent the risk of ground subsidence occurring in urban areas. Nevertheless, there is insufficient research effort on risk analysis that utilizes the correlation between the density of underground structures (i.e., the spatial quantity of buried objects installed in the ground around the interested area) and the occurrence of ground subsidence. In this paper, a study was conducted to analyze the line density of underground structures using GIS-based spatial information data, and to link this with the recorded ground subsidences. An optimization algorithm was developed to maximize the correlation between the line density of 29 recorded ground subsidences and 6 types of underground structures that occurred between 2010 and 2015 for the analysis area. The concept of normalized line density was also proposed for the analysis. The normalized line density of the analysis area was divided into five grades (Grade 1: lowest, Grade 5: highest). When the optimization algorithm was applied, the case where the normalized line density was Grade 4 or higher at the location of the recorded ground subsidences was about > 80%. It is thought that the density analysis result of underground facilities can be applied to the ground subsidence risk analysis by using the proposed optimization algorithm.

• Korean Journal of Construction Engineering and Management
• /
• v.22 no.2
• /
• pp.42-52
• /
• 2021

The cost of remodeling parking lots of apartment houses accounts for about 20 percent of the total cost of remodeling. This means that when the remodeling cost of the underground parking lot is known, it becomes possible to estimate the total construction cost. The standard of estimation referenced when calculating the construction cost is difficult to apply to calculating the remodeling cost. Thus, a construction cost estimation model that reflects the characteristics of remodeling construction is necessary. This study developed a basic construction cost estimation model for expansion remodeling of underground parking lots of apartment houses that calculates the approximate cost of construction by reflecting the characteristics and design elements of remodeling. Based on literature review and consultation with experts, 37 activities of underground parking lot remodeling construction were derived. In order to enable calculation of approximate construction cost before the remodeling design drawing is finalized, the quantity calculation formula and unit price for each activity were presented. Based on expert advice, 13 factors that affect the increase in construction cost and weights of each factor were determined. As a result of applying three cases of remodeling complexes to the basic cost estimation model, the accuracy was confirmed to be 93 percent on average.

• The Journal of the Convergence on Culture Technology
• /
• v.10 no.1
• /
• pp.585-590
• /
• 2024

In this study, rail surface defects are increasing due to the aging of urban railway rails, but in the detailed guidelines for track performance evaluation established by the country, rail surface damage is inspected with the naked eye of engineers and simple measuring tools. With the recent enactment of the Track Diagnosis Act, a large budget has been invested and the volume of rail diagnosis is rapidly increasing, but it is difficult to secure the reliability of diagnosis results using labor-intensive visual inspection techniques. It is very important to discover defects in the rail surface through periodic track tours and visual inspection. However, evaluating the severity of defects on the rail surface based on the subjective judgment of the inspector has significant limitations in predicting damage inside the rail. In this study, the rail internal crack characteristics due to rail surface damage were studied. In field measurements, rail surface damage locations were selected, samples of various damage types were collected, and the rail surface damage status was evaluated. In indoor testing, we intend to analyze the correlation between rail surface defects and internal defects using a electron scanning microscope (SEM). To determine the crack growth rate of urban railway rails currently in use, the Gaussian probability density function was applied and analyzed.

• Journal of Korean Society of Steel Construction
• /
• v.22 no.1
• /
• pp.1-12
• /
• 2010

According to the capacity design concept which forms the basis of the current steel seismic codes, the braces in concentrically braced frames (CBFs) should dissipate seismic energy through cyclic tension yielding and cyclic compression buckling while the beams and the columns should remain elastic. Brace buckling in inverted V-braced frames induces unbalanced vertical forces which, in turn, impose the additional beam moments and column axial forces. However, due to difficulty in predicting the location of buckling stories, the most conservative approach implied in the design code is to estimate the column axial forces by adding all the unbalanced vertical forces in the upper stories. One alternative approach, less conservative and recommended by the current code, is to estimate the column axial forces based on the amplified seismic load expected at the mechanism-level response. Both are either too conservative or lacking technical foundation. In this paper, three combination rules for a rational estimation of the column axial forces were proposed. The idea central to the three methods is to detect the stories of high buckling potential based on pushover analysis and dynamic behavior. The unbalanced vertical forces in the stories detected as high buckling potential are summed in a linear manner while those in other stories are combined by following the SRSS(square root of sum of squares) rule. The accuracy and design advantage of the three methods were validated by comparing extensive inelastic dynamic analysis results. The mode-shape based method(MSBM), which is both simple and accurate, is recommended as the method of choice for practicing engineers among the three.