• Journal of Korean Society of Steel Construction
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• v.27 no.1
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• pp.43-52
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• 2015

Constructions of buildings downtown are increasing as much as ever with a strong demand. Top-Down Method is suitable for its advantage in minimizing its disturbance to the neighborhood. Pre-founded when applied to CFT Column on-site welded is required for splicing. To complement the welded built-up square composite Column was developed. Top-down process will be pouring concrete in accordance with a step-by-step process. Thus, Pre-founded Column and cover concrete to determine the stress condition. Therefore, Concrete filled steel square tubular columns encased with precast concrete were studied. Five Centrally loaded Columns were tested to investigate the axial load carrying capacity. we analyzed the strength and behavior of CET Column by Loading conditions and concrete strength, thickness of cover concrete through structure experiments.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.279-280
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• 2018

The waterproofing material can be roughly divided into a coating material and a sheet waterproofing material. In the case of coating waterproofing materials, sheet waterproofing materials, which are easy to use in terms of workability and quality control, have been recently used because of their incomplete use of coating thickness, long curing time and poor blending due to in situ blending. However, in the case of the sheet waterproofing material, since the sheet overlapping portion is inevitably generated, various defects (breakage due to the behavior) are frequently observed. Therefore, it is imperative to establish fundamental measures to minimize this.

• Proceedings of the Korean Reliability Society Conference
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• 2001.06a
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• pp.257-263
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• 2001

In the analysis of product reliability, the fault tree is widely used since it shows the interrelations of the faults that lead to the product fault. A top-down approach based on experts’ experience is commonly used in the fault tree construction and the trees often take different forms depending on the intent of the analyst. In this work it is studied how to construct fault trees with the utilization of function trees obtained from analyzing the functions and sub-functions of products in order to suggest a generic way of fault tree construction. The function tree of a product is obtained by analyzing basic functions comprising the product main function in a bottom-up approach so that it enables to construct an objective fault tree. The fault tree for a scroll compressor is shown as an example.

• Proceedings of the KSME Conference
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• 2001.06c
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• pp.333-338
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• 2001

Fault tree is a widely used methodology for analyzing product reliability. The fault trees are usually constructed using the experiences of expert reliability engineers in top-down approaches and have different structures according to each expert's subjectivity. In this work it is tried to find a general method for the fault tree construction based on the function tree that is the result of product function deployment. Based on the function tree, the method has the advantage of resulting an objective fault tree since the faults are defined as the opposite concept of functions. The fault tree construction of this work consists of the following steps: 1) definition of product primary function with the viewpoints of product operation and configuration, 2) construction of functional relation chart using a grouping algorithm, 3) abstraction of functional block diagram according to operation sequences and configuration of a product, 4) construction of function tree for each viewpoint, and 5) construction of fault tree by matching the function tree and simplification of the result.

• Korean Journal of Construction Engineering and Management
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• v.16 no.1
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• pp.119-128
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• 2015

Domestic dominant method in subcontract cost estimate for comprehensive program management is estimation by referencing similar cases or relying on the experience and expertise of the engaged. However, this method is not reliable due to lack of accuracy, making it harder for clients to plan and budget the program. Since budget itself is roughly estimated, it becomes a source of cost rise in the course of management due to design modifications. Therefore, the client and service providers shall calculate more accurate service cost by applying objective and scientific method in order to minimize cost rise and cost related dispute. Traditional cases, in estimating program management cost, took Top-Down approach based on precedents and experience. On the contrary, this study will categorize management structure into phases and activities, issue WBS for each phase to estimated schedule and cost for each code, and take Bottom-UP approach. By taking this approach named ICEP (Integrated Cost Estimate based on Project), Set project typical model will be developed for service cost estimating, calculate cost by applying project-specific factors. Also, by analyzing progress data and allocated management cost to complement them, more efficient construction management will take shape based on program management cost standards which reflect project-specific features.

• The Transactions of the Korea Information Processing Society
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• v.6 no.2
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• pp.347-356
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• 1999

We present a method of thesaurus construction in order to produce semantic concept hierarchy of Korean nouns and implement a system for constructing the thesaurus in this paper. Multiple-step construction method is applied to this system which uses bottom-up and top-down method complementarily for solving the non-objectivity of word hierarchy, working speed, structural contradiction and incoherency of existing thesaurus. This system maintains objectivity using the meaning sentence of machine-readable dictionary and solves structural contradiction and incoherency with reference to existing thesaurus. We implement a developmental tool based on client/server system to construct thesaurus including massive entries as soon as possible and multiple client can work simultaneously.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2001.01a
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• pp.211-218
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• 2001

This paper introduces a method of constructing expert systems in an integrated environment for automatic software design. This integrated environment may be applicable from top-level system architecture design, data flow diagram design down to flow chart and coding. The system is integrated with three CASE tools, FSD (Functional Structure Diagram), DFD (Data Flow Diagram) and structured chart PAD (Problem Analysis Diagram), and respective expert systems with automatic design capability by reusing past design. The construction way of these expert systems is based on systematic acquisition of design knowledge stemmed from a systematic design work process of well-matured developers. The design knowledge is automatically acquired from respective documents and stored in the respective knowledge bases. By reusing it, a similar software system may be designed automatically. In order to develop these expert systems in a short period, these design knowledge is expressed by the unified frame structure, functions of th expert system units are partitioned mono-functions and then standardized components. As a result, the design cost of an expert system can be reduced to standard work procedures. Another feature of this paper is to introduce the integrated environment for automatic software design. This system features an essentially zero start-up cost for automatic design resulting in substantial saving of design man-hours in the resulting in substantial saving of design man-hours in the design life cycle, and the expected increase in software productivity after enough design experiences are accumulated.

• International Journal of Contents
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• v.5 no.3
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• pp.57-64
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• 2009

Korea has relied on top down development method, in which companies, research and education institutions move into the industrial complexes established by the government. However, to improve local competitiveness, the paradigm is shifting from the government initiated industrial complex to the clusters based on the cooperative network of the region. Representative case is 'Samcheok-si Fire & Emergency industry cluster construction project' that begun in 2007. AHP technique analysis results on first-stage showed that priority was on policy and network elements, and the results of second-stage analysis show that priority was on Policy incentives to internationalize the cluster and strengthen link,. Cluster branding, Sharing of organizational culture to cope with changes in environment, Creation of group learning culture. The subject of this research is limited to Samcheok-si's the Fire and Emergency Industry cluster formation project. Therefore, the research area and standard should be expanded to increase generality in further researches.

• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.6
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• pp.937-957
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• 2017

Urban roads are not only congested with vehicles and pedestrians, but also have many pipelines buried to provide convenience for inhabitants. In addition, urban inhabitants live comfortably in buildings adjacent to the road for residence, business, commerce, rest and so on. Therefore, despite the high cost of land, urban underground buildings with high land use efficiency are constantly being built. Recently, the construction of underground buildings has caused social problems such as the collapse of surrounding roads and adjacent buildings. Institutional improvement is being actively carried out to improve this. In this study, a new type of MSRC diaphragm wall was developed and a study on the construction method of underground building was carried out. It is intended to secure the underground excavation safety of underground buildings in urban areas and effectively prevent land subsidence complaints. Also, a reasonable design method of MSRC diaphragm walls using the ultimate strength design method is presented through the flexural performance Experiment.

• Geomechanics and Engineering
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• v.32 no.1
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• pp.111-123
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• 2023

The slope of an open cut tunnel is located above the exit of the Leijia tunnel on the Changgan high-speed railway. During the excavation of the open cut tunnel foundation pit, the slope slipped twice, a large landslide of 92500 m³ formed. The landslide body and unstable slope body not only caused the foundation pit of the open cut tunnel to be buried and the anchor piles to be damaged but also directly threatened the operational safety of the later high-speed railway. Therefore, to study the stability change in the slope of the open cut tunnel under heavy rain and excavation conditions, a 3D numerical calculation model of the slope is carried out by Midas GTS software, the deformation mechanism is analyzed, anti-sliding measures are proposed, and the effectiveness of the anti-sliding measures is analyzed according to the field monitoring results. The results show that when rainfall occurs, rainwater collects in the open cut tunnel area, resulting in a transient saturation zone on the slope on the right side of the open cut tunnel, which reduces the shear strength of the slope soil; the excavation at the slope toe reduces the anti-sliding capacity of the slope toe. Under the combined action of excavation and rainfall, when the soil above the top of the anchor pile is excavated, two potential sliding surfaces are bounded by the top of the excavation area, and the shear outlet is located at the top of the anchor pile. After the excavation of the open cut tunnel, the potential sliding surface is mainly concentrated at the lower part of the downhill area, and the shear outlet moves down to the bottom of the open cut tunnel. Based on the deformation characteristics and the failure mechanism of the landslides, comprehensive control measures, including interim emergency mitigation measures and long-term mitigation measures, are proposed. The field monitoring results further verify the accuracy of the anti-sliding mechanism analysis and the effectiveness of anti-sliding measures.