• 한국공작기계학회논문집
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• 제17권1호
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• pp.50-58
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• 2008

The SM45C metallic coupons have been tested under static tensile loading with acoustic emission (AE) as the load-deflection curve mainly. In this study, we used AE to detect the yielding of material and AE techniques was applied to rapidly estimate the mechanical characteristics of a material. First, coupons without an artificial defect were tested at different cross-head speed. For all cases in this analysis, yielding point of SM45C coupons did not appear definitely compared to mild steel, whereas coupons start to generate AE counts upon yielding. So all cases are normalized to know the possibility of accelerated life test of a material. And next, coupons with different from sizes of circular hole defects were tested at the same cross-head speed of 5 mm/min. Results were classified into 3 classes and analyzed by AE amplitude & signal strength as a function of time. Summarizing the specific conclusions, we need to additional research considering plate with width-ratio in order to estimate the fracture mechanism.

• Pediatric Infection and Vaccine
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• 제5권2호
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• pp.283-288
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• 1998

Recurrent meningitis in children is not only a potentially life threatening condition, but often involves the child in the trauma though repeated hospital admissions and multiple invasive investigations to find the underlying causes. Symptoms and signs of CSF rhinorrhea or otorrhea are infrequent in these patients and difficult to diagnose in young children. All young children treated for meningitis should then be administered an evoked potential audiometry as a post-treatment test. If sensorineural hearing loss is identified, the clinician should be alerted to the possibility of CSF leakage as the cause of the meningitis. Radiologic studies should be performed to rule out preexisting congenital, or acquired, abnormalities requiring surgical exploration. Two young children with recurrent meningitis due to a right cochlear aplasia and a cribriform plate defect caused by trauma are presented to illustrate the problems of diagnosis and management. A review of literatures will also be presented briefly.

• Industrial Engineering and Management Systems
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• 제9권3호
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• pp.251-261
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• 2010

This article demonstrated the application of the Fuzzy Data Envelopment Analytical Hierarchy Process (FDEAHP) to evaluate the root causes of critical defect problems occurring in the production of liquid medicine. The methodology of the research began by collecting the defect data by using Check Sheets, and ranking the significant problems by using a Pareto Diagram. Two types of major problems were found to occur, including glass fragments in the medicine and damaged lid threads. The causes of each problem were then analyzed by using Cause and Effect Diagrams. The significant causes were ranked by FDEAHP under three criteria, Severity (S), Occurrence (O) and Detection (D), followed by the framework of the FMEA Technique. Two causes with the highest Final Weight (FW) of each problem were selected to be improved, such as installing auxiliary equipment, using the Poka-Yoke system, setting the scale of the shaft and lathing the bushes of each bottle size. The results demonstrated a reduction in defects from 3.209% to 1.669% and showed that improving a few significant root causes, identified by an experienced decision maker, was sufficient to reduce the defect rate.

• 소성∙가공
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• 제32권5호
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• pp.276-286
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• 2023

The field of sheet metal forming using press technology has become essential in modern mass production systems. Draw bead is often used to enhance formability. However, optimal draw bead design often requires excessive time and cost due to iterative experimentation and sometimes results in some defects. Given these challenges, there is a need to enhance formability by introducing segmented blank holders without draw beads. In this paper, the feasibility of a localized holding strategy using segmented blank holders is evaluated without the use of draw beads. The possibility for improving the formability was evaluated by utilizing a combination of the forming limit diagram and the wrinkle pattern-based defect indicators. Artificial neural networks were used for predicting defect indicators corresponding to arbitrary input holding forces and the NSGA-II optimization algorithm is used to find optimum blank holder forces yielding better defect indicators than the original process with drawbeads. Using optimum holding forces obtained from the proposed procedure, the stamping process with the segmented blank holders can yield better formability than the conventional process with drawbeads.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 봄 학술논문 발표대회
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• pp.337-338
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• 2023

As the number of defects in apartments has increased recently, lawsuits and disputes related to defects have also increased. As a result, the loss of time and money is enormous. Therefore, fundamental measures are needed to reduce the occurrence of defects. Therefore, the purpose of this study is to propose a plan to reduce defects, focusing on window construction. To this end, existing studies were reviewed, and data from domestic construction companies were collected and classified to organize the types of defects. Based on the classified data, eight types with a high incidence of window glass were analyzed according to the time of occurrence, and the cause and causal relationship of the defect were schematized. It aims to identify the degree of possibility of recurrence of defects for each of the eight defect types for experts and derive key management elements using the RII method. Therefore, the goal is to select key management elements of window construction that actively reflect the characteristics of the construction stage.

• 소성∙가공
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• 제4권1호
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• pp.79-91
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• 1995

Precision forming of electronic components has appeared to be competitive according to manufacturing cost and dimensional tolerances. Now domestic electronic companies have been involving in utilization of the finite element method in process design of precision forming. A forming process to produce an electronic component, aperture, has been inbestigated to find out forming defects during multi-operations. The applications of the commercial FEM software MARC show a possibility of defect in precision coining process among the whole multi-process. Thus the coining process of three-dimensional deformation is analyzed using DAMF-3D which has been developed in this lab with the rigid-plastic algorithm. The result f simulations by DAMF-3D provides clear description of the defect involved in the coining process.

• Journal of Korean Dental Science
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• 제9권1호
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• pp.42-48
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• 2016

Prophylactic removal of impacted third molars is a common procedure in dentistry, but the necessity of routine extraction is still controversial. When impacted third molars caused severe apical root resorption of the second molars, orthodontic traction of the third molars after extraction of the damaged second molars could minimize alveolar bone defect and preserve the patient's natural teeth. By well-planned orthodontic treatment, functional occlusion was established avoiding extraction of the impacted teeth and eliminating the possibility of a large bone defect after extraction.

• Advances in pediatric surgery
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• 제2권2호
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• pp.148-150
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• 1996

Transmesenteric hernia, a type of internal hernias, is a rare cause of intestinal obstruction. This intraperitoneal hernia has no sac and is formed by protrusion of a loop of bowel through an aperture in the mesentery. Incarceration leads to intestinal obstruction and subsequently, strangulation and gangrene of varing lengths of intestine. This is a case report of 4-year-old girl with transmesenteric herniation of the terminal ileum through a defect in its own mesentery. Strangulation of the affected bowel necessitates resection and primary anastomosis with repair of mesenteric defect. The postoperative course was uneventful. Acute intestinal obstruction in the absence of an external hernia and with no history of a previous surgical procedure suggests the possibility of an internal hernia, especially if the patient has a history of chronic intermittent abdominal distress.

• 대한수의학회지
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• 제14권1호
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• pp.107-113
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• 1974

This study was performed for the purpose of investigating the possibility of epithelization on the defect of digestive tract after covering it with serosal wall of the cecum in the dog. The results obtained were as fallows: 1. Each defect of the digestive tract revealed almost complete formation of the mucous membrane and the muscle. Especially it was most fast in the jejunum. 2. Fistula formation was not found in all the experimental cases. The defects of small intestine and large intestine near the cecum were healed more fastly than the other portion. 3. The stomach and the duodenum appeared intestinal adhetion more frequently than the jejunum and the colon. Therefore, it is considered that covering with serosal wall of the cecum in the lower intestine is far better than in the upper intestine.

• 비파괴검사학회지
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• 제31권6호
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• pp.635-641
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• 2011

In ultrasonic testing of dissimilar metal welds, application of phased array technique in terms of incident beam focusing is not easy because of complicated material structures formed during the multi-pass welding process. Time reversal(TR) techniques can overcome some limitations of phased array since they are self-focusing that does not depend on the geometrical and physical properties of testing components. In this paper, we test the possibility of TR focusing on a defect within anisotropic, heterogeneous austenitic welds. A commercial simulation software is employed for TR focusing and imaging of a side-drilled hole. The performance of time reversed adaptive focal law is compared with those of calculated focal laws for both anisotropic and isotropic welds.