• The Journal of the Convergence on Culture Technology
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• v.6 no.1
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• pp.463-469
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• 2020

People enjoy more leisure time these days as the government introduced the workweek last year and there is a growing interest on living healthy life. Amidst such change in society, trekking in forest has gained popularity along more people spending leisure time by walking for health. As a result, there are many scenic trails being built using wood deck. Usually certain parts of trails are built with wood deck where the path maybe too dangerous for walking or where nature needs to be protected. However wood material used for deck is easily prone to defects which can lead to safety issues. This study aims to understand the differences by materials used for wood deck and to investigate a link between different materials used and causes for defect occurrence. And further, the study aims to identify materials and construction methods for high workability and safety. The study was able to conclude that different materials used and different construction methods of applied for wood deck yield different results in terms of workability and defect occurrence.

• Journal of the Korea Institute of Building Construction
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• v.15 no.4
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• pp.391-396
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• 2015

The demands about eco friendly space are increased as buildings are denser in downtown, and green system on the roof and the artificial ground are widely being applied. The construction of green system applies a waterproof layer, a root barrier and a protection concrete layer. Assembly of these many layers leads to a long construction term, and cause many defects. This study is to evaluate one layer-hybrid sheet which gets waterproof and root barrier performance simultaneously, which is developed to use in the new green system. As results, the performances of physical properties, durability, waterproof and root barrier not only exceeded quality standards but also showed excellent durability. In addition, mock-up test would be proceed to certify long term performance.

• Journal of the Korea Institute of Building Construction
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• v.22 no.1
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• pp.57-67
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• 2022

Tower cranes have an unstable superstructure, which means that there is a very high risk of accidents. It is necessary to establish preventive measures to ensure the safety of tower cranes at a time when active efforts are being made to reduce safety accidents involving tower cranes. As such, the purpose of this study is to analyze disaster cases to ensure the safety of tower cranes. For this study, 260 cases of tower crane disasters filed with the Korea Occupational Safety and Health Agency from July 2012 to July 2020 were analyzed. Through this analysis, it was found that lifting work was the most common of the work types, at 45.3%; while of the types of disasters, accidents caused by falls were the most common type, at 35.8%. In addition, with regard to the cause of accidents, work method defects was found to be the highest, at 38.8%. In the future, the findings of this study will be used as basic data to guide the establishment of policy to prevent tower crane accidents.

• Journal of the Korean Institute of Landscape Architecture
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• v.49 no.1
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• pp.1-18
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• 2021

This study was intended to present measures for the improvement of the apartment house landscaping supervision system by examining the adequacy of landscaping supervision, which is aimed at improving the quality of landscape plants and facilities in apartment house landscaping sites. Additionally, this study aims to identify the problems occurring in the process of the performance of landscaping supervision and to provide the evidence for legislative activities and revision of the laws currently being pushed forward for the mandatory deployment of apartment house landscaping supervision personnel. The results of the analysis showed that no landscaping supervision personnel was deployed to apartment complexes with less than 1,500 households and that the landscaping comprised 19% to 46% of the entire construction process. The civil engineering firm performed the landscaping supervision, which made it impracticable to fully focus on the construction quality in the field of landscaping. The quality control in terms of landscape plants revealed differences in quality control, depending on the competence and experience of the civil engineer supervising the personnel, where the landscaping supervision personnel was not deployed. The apartment houses landscaping supervision activity index was analyzed, and the results showed that the supervision activity index for apartment house A was 72.0, B was 70.4, and apartment houses C to G ranged from 38.7 to 46.9, which suggested that the difference in quality control, process control, and technical support affected the construction quality and occurrence of defects.The improvement of landscaping process quality control and process management will be carried out more smoothly and the rate of defects will be drastically reduced if the landscaping supervision personnel placement threshold is lowered from 1,500 households to 300 households in complexes. The results of this study are expected to be useful in promoting and re-establishing the landscaping industry based on the improvement of construction quality in the field of landscaping in connection with the construction of apartment houses.

• Journal of the Korea Institute of Building Construction
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• v.13 no.3
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• pp.235-241
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• 2013

In this study, a mortar was produced using re-dispersible polymer powders that addresses the defects of aqueous polymer and improves the durability of cement mortar. Also, an attempt was made to examine the properties of polymer modified mortars using re-dispersible polymer powders by strength and durability tests between ordinary Portland cement mortars and polymer modified mortars mixed with aqueous dispersion. The test showed that strength and durability are improved considerably compared with ordinary Portland cement mortar, and the performance of aqueous polymer cement mortar was considerably improved. Accordingly, it is expected that high-quality prepackaged polymer modified mortars can be produced using re-dispersible polymer powders.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.5
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• pp.1343-1356
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• 2013

Cloud computing has emerged as perhaps the hottest development in information technology at present. This new computing technology requires that the users ensure that their infrastructure is safety and that their data and applications are protected. In addition, the customer must ensure that the provider has taken the proper security measures to protect their information. In order to achieve fine-grained and flexible access control for cloud computing, a new construction of hierarchical attribute-based encryption(HABE) with Ciphertext-Policy is proposed in this paper. The proposed scheme inherits flexibility and delegation of hierarchical identity-based cryptography, and achieves scalability due to the hierarchical structure. The new scheme has constant size ciphertexts since it consists of two group elements. In addition, the security of the new construction is achieved in the standard model which avoids the potential defects in the existing works. Under the decision bilinear Diffie-Hellman exponent assumption, the proposed scheme is provable security against Chosen-plaintext Attack(CPA). Furthermore, we also show the proposed scheme can be transferred to a CCA(Chosen-ciphertext Attack) secure scheme.

• Journal of the Korean Institute of Landscape Architecture
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• v.32 no.5
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• pp.35-42
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• 2004

This study examines the traffic noise reduction effects of the diverse efficiency features of a sunken square, and investigates the reduction effects and characteristics of noise alterations according to the construction conditions in order to verify its possibility as a new noise reduction facility. The measured data were analyzed. As a result, (1) the traffic noise from the roads around the sunken squares exceeded the regulatory standards; (2) the sunken squares were protected from noise; (3) the sunken spaces yielded a greater reduction by 6∼7dB than the flat ground thanks to the diffraction effect; and (4) there were fine changes to noise according to the conditions of space construction. In short, a sunken square has the potential to afford new applications as a noise reduction facility in a highly concentrated downtown with the existing defects solved. In addition, its use for effective noise control is evident based on the noise characteristics of a space. Future studies need to include efforts to provide clearer quantitative data, as well as research on shape, layout, and materials.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.234-235
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• 2017

The bonding of the asphalt-based waterproof sheet is carried out in such a manner that the sheet and the sheet are adhered together and the lower adhesive layer of one sheet is adhered to the upper film layer of the other sheet, and the asphalt layer and the PE or HDPE film layer are bonded. When the joints are formed in the form of junctions between heterogeneous materials and exposed to the concrete joint movements and other deteriorating factors, the integrity of the joints can deteriorate and problems such as lifting and peeling off of the joints can occur. Therefore, this study was carried out to prevent unstable joint adhesion of the asphalt compound and film layer and to prevent defects in the adhesion between self - adhesive waterproof sheets. The self-adhesive waterproof sheet of this study can maximize bond stability by inducing bond between asphalt compounds during sheet-to-sheet bonding, thereby improving bonding strength.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2006.11a
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• pp.57-60
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• 2006

This study proposes the physical properties of the hardened lightweight cement using the polyethylene tube and to make the fundamental data regarding a new lightweight concrete development. The aerated concrete is displaying various effects such as lightweight, insulation characteristic and it is coming to be widely applied the slab layer of apartment as an insulating material but currently the aerated concrete has many problems. Therefore, demonstrating similar property of former aerated concrete and improving the defects, developing new hardened cement is needed. In this study, we predict adopting possibility of hollow core polyethylene tube, as a material to make cement hardening containing a lot of void. So we changed the mixing ratio, a diameter and length of the polyethylene tube and improved the compressive strength and unit capacity weight of the lightweight cement hardening body. From the test results, we judge that the aerated concrete is a developmental possibility.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2003.10a
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• pp.333-339
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• 2003

Recently, the bridges become greater according to development of a construction technology. This phenomenon requires long span bridge, so that increases the dead weight. The orthotropic steel deck bridges have much advantages such as the light dead weight and the reduction of construction period. And almost whole process of carried out is manufactured at factory, so it can cause the increase of quality authoritativeness. But orthotropic steel deck bridge is consist of structure by welding, it can not avoid a lot of welding jobs, defects and transformation by welding are becoming problem accordingly. Specially, topical stress concentration phenomenon in cross connection area of longitudinal and transverse rib causes fatigue failure. The Bulkhead Plate for prevention of this stress concentration phenomenon was applied by changing the orthotropic steel deck of Williamsburg bridge in USA. But, it is principle that a Bulkhead Plate is not established in the domestic design standard. Therefore, it is estimated that the study for installation of Bulkhead Plate is needed. This treatise with considering these circumstances proves efficiency of Bulkhead Plate and will be presented optimal design details through finite element analysis according to change the geometrical of Bulkhead Plate and tile cross-connection area of longitudinal and transverse rib.