• Advances in concrete construction
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• v.10 no.5
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• pp.381-391
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• 2020

This study aimed to develop reference materials (RMs) for mortar that can simulate the initial flow characteristics with constant quality over a long period. Through the previous research on the development of RMs for cement paste, the combination of limestone, glycerol, and water was used as the basic matrix for developing RMs for mortar in this study. In addition, glass beads of three particle sizes (0.5, 1.0, and 2.0 mm) and ISO standard sand were selected as tentative candidates to derive fine aggregate substitutes. The mixture of glass beads could simulate the initial flow characteristics of mortar, but under the same mixing ratio, replicates showed an unstable tendency to indicate inconsistent values due to the generation of electrostatic properties between materials and equipment. On the other hand, the mixture using ISO standard Sand not only simulates the constant flow characteristics for a long period of time, but also shows stable results with little error in replicates. Therefore, limestone, glycerol, ISO standard sand, and water were finally determined as components that met the required properties of RMs for mortar. The effect of each component on the flow characteristics of RMs was analyzed. It was found that glycerol increased the cohesion between the particles of standard sand, resulting in a constant increase both in the plastic viscosity and yield stress. Both limestone and standard sand had a dominant effect on the yield stress. The relationships between various mortar mixing ratios and the corresponding mixing ratios of RMs were established. In addition, the results of the verification experiment showed that the rheological properties of the RMs obtained through the relationships correlated with various water/cement ratios and the fine aggregate volume fractions of mortar obtained with same manner. In other words, the RMs for mortar developed in this study can be used as standard samples because they can simulate the initial flow characteristics of mortar of various mixing ratios for a long period without any chemical changes.

• Journal of the Korean Institute of Landscape Architecture
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• v.41 no.1
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• pp.60-70
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• 2013

This study focused on analyzing classification system, technique methods, quality levels of periodic amendment characteristics in planting of standard specification. Through analyzing the above and comparing with foreign case study, this study suggests the improvement directions. The results improvement directions are as follows. 1. Many kinds of new construction were set up through the amendments of Landscape Standard Specification, but there are still needs to combine some construction categories because of mismatches between upper and lower categories. 2. Although the Landscape Standard Specification was revised to be more concrete, the contents there remains an ambiguous expression. So, standard specification is needed to revise a depth of earth ball or strength of support materials and quantify collect period of topsoil and application time. In addition, standards about following supervisor's instruction should be more detailed or deleted. 3. The standard specification has not been specified despite enactment and amendments reflecting the periodical paradigm and the needs of users, so it is still needed to revise. In addition, quality levels, planting periods, size of earth ball and performance criteria of tree materials are needed to revise. Each specific classification and construction methods were made by amendments of standard specification, but some standards are not clear and concrete. Therefore, the standard specification is needed to revise the classification system, technique methods, and problem deduction of quality levels and proposal of improvement. This study will be reference material when Landscape Standard Specification is revised.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.1
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• pp.73-81
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• 2018

The purpose of this study is to research the regulation of durability standard of underground structures monitoring sensors. The durability criteria for construction monitoring sensors of domestic construction companies, the standard years of contents such as buildings on the income tax implementation regulations, and the standards of the Public Procurement Service for construction monitoring and construction machinery were analyzed. The durability criterion on products such as the inclination meter and the strain gauge, which are purchased from the Public Procurement Service prior to installation on the underground structure, is 8 to 10 years. It is considered that the monitoring sensor installed in the paperboard and the concrete structure at the time of construction will have considerably shortened service life rather than the useful life of the product itself due to various adverse factors such as groundwater influence and compaction.

• Korean Journal of Construction Engineering and Management
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• v.13 no.6
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• pp.33-44
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• 2012

This study is as to payment improvement method of additional incidental cost to be occurred upon extension of public construction time. According to the result of analysis about the cause of non-payment of additional incidental cost of construction time extension through site examples, it was found that difficulties exist in disputes & proofing over the scope of actual cost recognition, and in this regard the result of experts opinion indicated that a construction extension pre-agreement system can be executed which agrees the scope of recognition of additional incidental cost of construction time extension once the statistical standard is clear and accurate. Accordingly, in this study, by totalling multiple sites data, calculations were implemented in terms of type of construction projects, amount of constructions, period of constructions. According to the result of calculation, the element of type of construction project and construction period appears to have none direct effect to the occurrence of additional cost of construction time extension, but direct relationship was indicated related to the contract amount element. In view of above, in this study a standard additional incidental cost of construction time extension was proposed, and presented a system improvement plan to implement the construction extension pre-agreement system.

• Journal of The Korea Institute of Healthcare Architecture
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• v.24 no.1
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• pp.7-14
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• 2018

Purpose: This study analyzes mental healthcare delivery services and types of facilities, the status of installation and operation, and planning standard. The purpose of the study is to propose a basic data for the performance of related research and work tasks, along with an understanding of the Chinese mental healthcare facility type and support system. Furthermore, it will show a lack of current function management as the changes of mental health concept and demand for services increases, and it is intended to provide implications for the construction of mental health facilities. Methods: This study was conducted by a research on law and regulation of China's mental healthcare delivery service system and mental healthcare facility. The analyzed data are the national standard GB, the optional national standard GB/T, the building construction standard JGJ, and the report issued by the Health Planning and Development Committee. Results: At present mental healthcare facility construction in China is in the period of rapid development and it exposes the layout of medical facilities, which is not currently reasonable and the service does not reach the designated position and so on. Overall, it requires more detailed guidelines to enhance the quality of mental healthcare service. Implications: It is expected that the research of this paper will provide effective reference for future research on Chinese Mental healthcare system and facilities, and can promote construction of Chinese mental healthcare facility theory in perfect condition.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.15 no.1
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• pp.9-17
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• 2019

Reducing global warming potential has become important, and as one of those methods for reducing it, economic evaluation by applying ice thermal storage air conditioning system was performed. The floor area and height of the subject building was assumed $5,000m^2$ and 20 m. Absorption chillerheater system and air source heat pump system was used for comparing to the subject system, and payback period method was used to perform economic evaluation. Although the running cost of ice thermal storage system is reduced compared to two systems, the ratio is not significant compared to the increase of initial construction expenses, and payback period was calculated to be about 7.7 and 79.3 years. However, the heat storage system should be approached from the viewpoint of long term rather than the economic standard in the present standard.

• Korean Journal of Construction Engineering and Management
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• v.23 no.6
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• pp.3-14
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• 2022

Quantitative analysis of the number of construction workers and construction period can present a new standard for appropriate personnel. This study presents a Queueing model that predicts the execution time of work procedures, the most important factor among work efficiency indicators. During the working cycle of apartment frame construction the same process tends to be repeated the volume of contruction. Based on these characteristics, this study used a Queueing Model and analyzed reference layer cycle of the delayed frame construction. After adjusting the number of people and the construction period, the performance of the model was analyzed and suggested. This study aims to support the decision making of personnel distribution according to the volume of construction by performing a performance analysis of the Queueing Model.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.11a
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• pp.13-14
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• 2011

The main purpose of this research is to propose standardization of construction components design with BIM and to develop WLCM Framework and Application System for supply chain management on interaction of stakeholders based on proposed standard component. To accomplish main purpose of this research, we planned three years period, in first year, we will develop model for building lifecycle based on BIM, and this model can give the chance of collaboration with stakeholders of building project. In second year, we will develop WLCM system with model, and to improve performance of application model/system. This study can contribute on reduction of whole lifecycle cost, with preventing omission of factors on cost reduction possibility, develop concurrent engineering framework for construction stakeholders with proposed BIM.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2008.05a
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• pp.153-157
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• 2008

The construction market has gradually become complexity, variety and specialization, and then owner's requirements about quality has become various. In order to solve the problem such as stated above, advanced constructions in United Kingdom, Japan and United States have introduced warranty contract which is warranted to quality and performance for need of owner in determined term to ensure the quality of construction since 1960s. However, the interior of a country encounter another problem result from defects liability what indefiniteness of defects standard, excess responsibility period, social recognition of be identical fraudulent work and defects, and contract with ascendancy of owners. etc, so builders concerned more excess defects liability than the quality of construction. The purpose of this study is to analysis of warranty contract in order to solve the problem such as stated above.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2007.04a
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• pp.89-92
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• 2007

Since 1960s, advanced constructions have introduced warranty contract which is warranted to quality and performance for need of owner in determined term to ensure the quality of construction. However, the interior of a country encounter another problem result from Defects Liability what indefiniteness of defects standard, excess responsibility period, social recognition of be identical fraudulent work and defects, and contract with ascendancy of owners. etc, so builders concerned more excess defects liability than the quality of construction. The purpose of this study is to analysis of warranty contract in order to solve the problem such as stated above.