• Journal of the Korean Institute of Gas
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• v.14 no.4
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• pp.37-44
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• 2010

To propose a cause analysis method of pressurized facilities, a likelihood of failure (LOF) for the thinning module by hydrochloric acid corrosion was analyzed through the risk-based inspection (RBI) using API-581 BRD. For this investigation, the technical module subfactor (TMSF), as a main factor of the LOF, was estimated, and the effects of parameters on the TMSF were analyzed quantitatively. As a result, we found that the TMSF increased with increasing chloride ion concentration and temperature, but it decreased with increasing thickness of the facilities, inspection number and inspection effectiveness. Also, the TMSF showed a relatively low value for the monitoring system implemented and the overdesign factor>1.5. In this condition, the TMSF changed sensitively with the inspection number, the inspection effectiveness and the overdesign factor, and its magnitude varied with the monitoring system.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.44 no.3
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• pp.214-229
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• 2021

There is an increasing need for complex and large projects to be carried out quickly. As the duration, size, and cost of the project increase, concerns about project failure are also rising. Finding factors that hinder the performance of an effective project and eliminating them in advance or controlling and managing them more effectively can be a more direct way to secure the success of the project. Previous studies have identified compositional dimensions that are classified according to attributes, covering the various obstacles that affect the success of the project through existing literature. It is a follow-up to previous research. Using DEMATEL techniques, we would like to propose to explore the appropriate measures that an entity and organization can take by identifying the causality between factors through cross-impact analysis of project disabilities and even presenting factors that may arise when they are identified. As a result of the analysis, according to the indicators to evaluate the importance, 8 factors were found to be relatively important factors, excluding the factors that Failure of project feasibility analysis and Technical environment change. In addition, 5 factors were found to be causative factors; Technical environment change, Unclarity project plan, Strategic consistency error, Inaccuracy of requirement definition, and Failure of project feasibility analysis. In contrast, the remaining 5 factors were found to be the result factors; Lack of benefits realization, Negative attitude of top management, Stakeholder conflict, Difficulty of process management, and Disturbance of communication.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.26 no.4
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• pp.201-212
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• 2023

Purpose: The gastrointestinal system is the most commonly affected organ, followed by the lungs, in patients with primary immunodeficiency disease (PID). Hence, it is common for children with PIDs to present with gastrointestinal symptoms. We aimed to analyze the clinical and histopathological findings of patients who were initially admitted to pediatric gastroenterology/hepatology clinics and subsequently diagnosed with PIDs to identify the clinical clues for PIDs. Methods: The demographic, laboratory, and histopathological findings, treatment modality, and outcomes of patients initially admitted to the pediatric gastroenterology/hepatology unit and subsequently diagnosed with PIDs were recorded. Results: The study included 24 patients (58.3% male; median age [range]: 29 [0.5-204] months). Common clinical presentations included chronic diarrhea (n=8), colitis (n=6), acute hepatitis (n=4), and acute liver failure (n=2). The association of autoimmune diseases, development of malignant diseases, and severe progression of viral diseases was observed in 20.8%, 8.3%, and 16.6% of the patients, respectively. Antibody deficiency was predominantly diagnosed in 29.2% of patients, combined immunodeficiency in 20.8%, immune dysregulation in 12.5%, defects in intrinsic and innate immunity in 4.2%, autoinflammatory disorders in 8.3%, and congenital defects of phagocytes in 4.2%. Five patients remained unclassified (20.8%). Conclusion: Patients with PIDs may initially experience gastrointestinal or liver problems. It is recommended that the association of autoimmune or malignant diseases or severe progression of viral diseases provide pediatric gastroenterologists some suspicion of PIDs. After screening using basic laboratory tests, genetic analysis is mandatory for a definitive diagnosis.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2008.11a
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• pp.591-596
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• 2008

Success or failure highly depends on delivery method in construction projects. This paper mainly focused on operation model for technical proposal in Large construction projects. This operational model uses Technical Proposal-Based Tender. This project studied order and delivery method in large construction projects. And delivery systems of international and domestic market are researched, and then condition of delivery system and problems are derived from them. Especially, it researched that it is hard to reflect special feature in large construction projects. As a result of having referenced idea as describe above, this paper will be studied by this process. First, definition of delivery method and large construction projects is researched. Second, delivery systems of international and domestic market are checked. Third, problems and condition of delivery system in large construction projects are investigated. Fourth, application of operation model for technical proposal-based tender are presented in large construction projects.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.544-544
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• 2014

Energy harvesting technology, which scavenges electric power from ambient, otherwise wasted, energy sources, has been explored to develop self-powered wireless sensors and possibly eliminate the battery replacement cost for wireless sensors. Among ambient energy sources, vibration energy can be converted into electric power through a piezoelectric energy harvester. For the last decade, although tremendous advances have been made in design methodology to maximize harvestable electric power under a given vibration condition, the research in reliability assessment to ensure durability has been stagnant due to the complicated nature of the multiple failure modes of a piezoelectric energy harvester, such as the interfacial delamination, fatigue failure, and dynamic fracture. Therefore, this study presents the first-ever system reliability analysis for multiple failure modes of a piezoelectric energy harvester using the Generalized Complementary Intersection Method (GCIM), while accounts for the energy conversion performance. The GCIM enables to decompose the probabilities of high-order joint failure events into probabilities of complementary intersection events. The electromechanically-coupled analytical model is implemented based on the Kirchhoff plate theory to analyze its output performances of a piezoelectric energy harvester. Since a durable as well as efficient design of a piezoelectric energy harvester is significantly important in sustainably utilizing self-powered electronics, we believe that technical development on system reliability analysis will have an immediate and major impact on piezoelectric energy harvesting technology.

• The Journal of Engineering Geology
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• v.14 no.1
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• pp.71-80
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• 2004

The failure of cut slopes frequently occurs particularly during the thawing season and the rain season in summer. This study interpreted data collected from site to which a real-monitoring system was applied in order to analyze the causes of ground behaviors and to forecast future slope failure. As for research methods, this study analyzed the size and mechanism of failure by integrating the results of field surveys and measurements. Furthermore, it analyzed data transmitted by the monitoring system installed in the a result, three times of ground displacement occurred as well as a number of partial tension cracks. The cut slope composed of sandstone and siltstone started its initial behavior as a result of torrential downpour and the loss of support of the substructure. For quantitative analysis of the characteristics of ground behavior, this study measured 5 lateral lines. According to the result of the measurement, displacement happened little in the section to which countermeasure had been applied, but displacement of maximum 400mm happened in the section to which countermeasure had not bee applied. The analysis of data on displacement and rainfall suggested a close relationship between ground behavior and rainfall. According to the result of stability interpretation along with the change of ground saturation, stability rate appeared to be less than 1.0 when ground saturation is over 55%. Although the current trend of ground behavior is at a stable stage falling within the range of tolerance, it is considered necessary to continue monitoring and data analysis because ground displacement is highly possible with the change of temperature during the winter.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2001.10a
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• pp.31-34
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• 2001

The customer unsatisfaction in the new products exists, though the most of enterprises using QFD. It is mainly caused by the failure of corrective determination of technical importance rating(TIR). To derive the technical importance rating, the impact of the fulfillment of design requirements on the satisfaction of customer requirements must first be quantified. This has been accomplished through the use of a 1-3-9 or a 1-5-9 scale and ignored the peak of the house of quality(HOQ). In this paper we suggested the methodology reflecting effectiveness among engineering characteristics and adjusting the relationship strength between customer attribute(CA) and engineering characteristic (EC), by using limit probability and PCMR(pairwise comparison and median rank). With using this method, the determination of TIR would be more suitable for the voice of customers objectively. Here negative correlation is ignored.

• Computers and Concrete
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• v.8 no.6
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• pp.631-645
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• 2011

The capacity design rule for beam-column joints, as adopted by the EC8, forces the formation of the plastic hinges to be developed in beams rather than in columns. This is achieved by deriving the design moments of the columns of a joint from equilibrium conditions, assuming that plastic hinges with their possible overstrengths have been developed in the adjacent beams of the joint. In this equilibrium the parameters (dimensions, material properties, axial forces etc) are, in general, random variables. Hence, the capacity design is associated with a probability of non-compliance (probability of failure). In the present study the probability of non-compliance of the capacity design rule of joints is being calculated by assuming the basic variables as random variables. Parameters affecting this probability are examined and a modification of the capacity design rule for beam-column joints is proposed, in order to achieve uniformity of the safety level.

• Earthquakes and Structures
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• v.12 no.5
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• pp.559-567
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• 2017

Slender structures like reinforced concrete (RC) chimneys are severely damaged or collapsed during severe wind storms or strong ground motions all over the world. Today, with the improvement in technology and industry, most factories need these slender structures with increasing height and decreasing in shell thickness causing vulnerable to winds and earthquakes. Main objectives in this study are to make structural wind and earthquake analysis of RC chimneys by using a well-known international standard CICIND 2001 and real recorded time history accelerations and to clarify weak points of these tall and slender structures against these severe natural actions. Findings of this study show that maximum tensile stress and shear stress approximately increase 103.90% and 312.77% over or near the openings on the body of the RC chimneys that cause brittle failure around this region of openings.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.35 no.3
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• pp.37-42
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• 2003

Physical properties of paper can be explained in terms of the changes in fiber's morphological properties. As the paper machine speed increases, the basis weight decreases and the mixing ratio of inferior recycled fibers increases, paper break becomes important than ever before. One of the objectives of this study is to analyze paper's physical, mechanical and fracture mechanical properties depending on softwood(SW) and hardwood(HW) mixing ratios and recycling. Fibers were refined by Valley beater to 450 mL CSF. Handsheets of 30 g/$\textrm{m}^2$ were prepared at different mixing ratios. Fracture toughness was measured as the amount of energy applied to cracked sample before total failure. Fracture toughness showed different trend to other strength properties. At the mixing ratio of SW 80: HW 20, papers showed the maximum fracture toughness. At this mixing ratio, flexible softwood fibers were mostly broken and stiff hardwood fibers were mostly pulled out.