• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2007년도 춘계학술대회 논문집
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• pp.160-164
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• 2007

In the steel industry, there is a need to produce large forged parts for the automobile industries, the flight and shipping industries ad military industries. In the steel-industry application, a cogging technique for cast ingots is required, because the major parts are needed as one large body in order to obtain higher quality. Therefore, cogging process is the primary step in manufacturing of practically large open-die forging. In the cogging process, internal voids have to be eliminated as defects, The present work is concerned with the elimination of the internal voids in large ingots so as obtain sound products. In this study, hot compression tests were carried out to obtain the flow stress of cast microstructure at different temperature and strain rates. The FEM analysis are performed to investigate the overlap defect of cast ingots during cogging stage. The measure flow stress data were used to simulate the cogging process of cast ingot using the practical material properties. Also the analysis of void closure are performed by using the $DEFORM^{TM}$-3D. The calculated results of void closure behavior are compared with the measured results before and after cogging, which are scanned by the X-ray scanner. From this result, the criteria for deformation amounts effect on the void closure can be investigated by the comparison of practical experiment and numerical analysis.

• Asia Marketing Journal
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• 제14권4호
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• pp.167-188
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• 2013

In today's society with its emphasis on unlimited information access, control of available information about high-technology products is often vital to their success. When a product is released, consumers may initially be attracted through information about its remarkable internal and external features. They may also perceive a degree of congruence between their own personalities and the product image as more information becomes available over time. Consumers' changing impressions of the product may influence personality congruence negatively or positively. These changes and their effects on preference for high-technology products are the focus of this paper. A survey was given to a sample of 206 students at K University to investigate the degree to which consumer behavior can be influenced by personality congruence. The need for clear and definite product knowledge in this process and the effect of product information on preference were also investigated. Three analyses were conducted. The results of Analysis 1 showed the influence of personality congruence on preference for high-technology products. Judgments about personality congruence were based on non-compensatory rather than compensatory information processing. The respondents considered certain aspects of a product's personality rather than the product as a whole when making preference decisions. The results of Analysis 2 indicated that when less information was available about a product, consumers who perceived high personality congruence with the product tended to have higher preference for it compared to those who perceived low personality congruence with the product. On the other hand, when consumers were given more information, no difference was observed in the impact of personality on preference between perceived high and low personality congruence. Lastly, the results of Analysis 3 showed that when consumers with high need for closure (NFC) perceived high congruence between their own personalities and a product, objective information regarding the product was not used in decision-making: instead, judgments about the product were based on perceived personality congruence. On the other hand, high-NFC consumers who perceived low personality congruence between themselves and the product tended to require more information about the product in order to give it a positive evaluation. In contrast, low-NFC consumers who perceived high personality congruence felt comfortable with large amounts of information. For low-NFC consumers who perceived low congruence, the level of information had no influence on preference.

• 소성∙가공
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• 제16권4호
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• pp.293-298
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• 2007

Recently, there is a need to produce a large forged part for the flight, shipping, some energies, and military industries, etc. Therefore, an open die forging technique of cast ingots is required to obtain higher quality of large size forged parts. Cogging process is one of the primary stages in many open die forging processes. In the cogging process prior to some open die forging processes, internal cavities have to be eliminated for defect-free. The present work is concerned with the elimination of the internal cavities in large ingots so as to obtain sound products. In this study, hot compression tests were carried out to obtain the flow stress of cast microstructure at different temperature and strain rates. The FEM analysis is performed to investigate the overlap defect of cast ingots during cogging stage. The measured flow stress data were used to simulate the cogging process of cast ingot using the practical material properties. Also the analysis of cavity closure is performed by using the $DEFORM^{TM}-3D$. The calculated results of cavity closure behavior are compared with the measured results before and after cogging, which are scanned by the X-ray scanner. From this result, the criteria for deformation amounts effect on the cavity closure can be investigated by the comparison between practical experiment and numerical analysis.

• 한국IT서비스학회지
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• 제21권2호
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• pp.1-26
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• 2022

This study classified five types of online food subscription economy: replenishment, curation, surprise, membership, and visitation. An online survey was conducted with 314 customers who experienced 5 types of online subscription economy. This study selected the characteristics of the food subscription economy as convenience, perceived personalization, economic utility, and timeliness through previous studies. The effect of the four characteristics on perceived value (utilitarian and emotional) and the relationship between customer engagement and perceived value, which are dependent variables that have never been used in the food subscription economy, were verified through the S-O-R model. In this relationship, we demonstrated how consumers' personal tendencies, such as need for cognitive closure and self-efficacy, mediate between timeliness and perceived value related to online food delivery. The study results are as follows. Perceived personalization, convenience, and timeliness had a positive effect on the utilitarian value in the order. It also had a positive effect on emotional values in the order of perceived personalization and timeliness. On the other hand, economic utility had no significant effect on practical branches. Customer engagement had a positive effect in the order of emotional value and utilitarian value. The lower the need for cognitive closure the more positive the utilitarian value. The lower the self-efficacy, the more positive the emotional value was perceived. Through the above study, companies that want to operate or start an online food subscription economy need a strategic approach rather than unreasonable price discounts in pricing policy. In addition, it is necessary to focus on marketing activities that provide emotional value by focusing on perceived personalization, which is the satisfaction factor of online food subscription.

• 지능정보연구
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• 제29권3호
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• pp.361-381
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• 2023

기업 부도 예측에 관한 연구는 재무정보를 중심으로 연구되어 왔다. 기업의 재무정보는 분기별로 갱신되기 때문에 실시간으로 기업의 폐업 가능성을 예측하는 데 있어 적시성이 부족하게 되는 문제가 발생한다. 이를 개선하고자 하는 평가 기업에서는 대상 기업의 건전성을 판단하기 위한 재무정보 외의 정보를 활용한 기업의 건전성을 판단하는 방법이 필요하다. 이를 위해 정보 기술의 발달로 기업에 대한 비재무정보 수집이 용이해지면서 기업 부도 예측에 재무정보 외의 추가적인 변수와 여러 가지 방법론을 적용하는 연구가 진행되어 왔으며, 이 중에서도 어떤 변수들이 기업의 부도를 예측하는데 영향을 주는지를 밝히는 것이 중요한 연구 과제가 되었다. 본 연구에서는 전자결제서비스를 이용하는 사업자의 폐업을 예측할 때 비재무정보를 구성하는 전자결제 정보들이 얼마나 영향을 미치는지를 살펴보았으며, 재무정보와 비재무정보 결합에 따른 폐업 예측 정확도 차이를 살펴보았다. 구체적으로, 재무정보 모형과 비재무정보 모형, 그리고 이를 결합한 모형으로 구성된 세 가지 연구 모형을 설계하였으며 Multi Layer Perceptron(MLP) 알고리즘을 포함한 여섯 가지 알고리즘으로 폐업 예측 정확도를 확인하였다. 재무정보와 비재무정보를 결합한 모형이 가장 높은 예측 정확도를 보였으며, 그 다음으로는 비재무정보 모형, 재무정보 모형의 순서로 예측 정확도가 확인되었다. 알고리즘별 폐업 예측 정확도는 여섯 가지의 알고리즘 중 XGBoost가 가장 높은 예측 정확도를 보였다. 사업자의 폐업 예측에 활용된 전체 87개의 변수를 대상으로 상대적 중요도를 살펴본 결과 폐업 예측에 중요하게 영향을 미친 변수는 상위 20개 중 70% 이상이 비재무정보인 것으로 확인되었다. 이를 통해 비재무정보의 전자결제 정보가 사업자의 폐업을 예측하는 중요한 변수임을 확인하였으며, 비재무 정보가 재무정보의 대안적 정보로서 활용할 수 있는 가능성 역시 살펴볼 수 있었다. 본 연구를 기반으로 사업자의 폐업을 예측할 수 있는 정보로서 비재무정보의 수집과 활용에 대한 중요성을 인식하고 기업의 의사결정에 활용할 수 있는 방안에 대해서도 다루었다.

• Structural Engineering and Mechanics
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• 제18권6호
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• pp.731-744
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• 2004

Modified virtual crack closure integral (MVCCI) technique has become very popular for computation of strain energy release rate (SERR) and stress intensity factor (SIF) for 2-D crack problems. The objective of this paper is to propose a numerical integration procedure for MVCCI so as to generalize the technique and make its application much wider. This new procedure called as numerically integrated MVCCI (NI-MVCCI) will remove the dependence of MVCCI equations on the type of finite element employed in the basic stress analysis. Numerical studies on fracture analysis of 2-D crack (mode I and II) problems have been conducted by employing 4-noded, 8-noded (regular & quarter-point), 9-noded and 12-noded finite elements. For non-singular (regular) elements at crack tip, NI-MVCCI technique generates the same results as MVCCI, but the advantage for higher order regular and singular elements is that complex equations for MVCCI need not be derived. Gauss numerical integration rule to be employed for 8-noded singular (quarter-point) element for accurate computation of SERR and SIF has been recommended based on the numerical studies.

• Journal of Periodontal and Implant Science
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• 제38권4호
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• pp.723-728
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• 2008

Purpose: During guided bone regeneration procedures for the augmentation of deficient alveolar ridge, primary closure of flap is necessary. For primary flap closure, flap is repositioned coronally and the zone of attached keratinized mucosa may decreased. The need for attached keratinized mucosa around dental implants is still controversial, but sufficient peri-implant attached keratinized mucosa would be beneficial for functional and esthetic aspects. This case report presents three cases that demonstrated free gingival graft for increasing the zone of peri-implant attached keratinized mucosa which was decreased after guided bone regeneration. Materials and Methods: In first case, maxillary incisors were extracted and guided bone regeneration was performed simultaneously. Because the membrane was exposed at 3 weeks after operation, the membrane was removed and free gingival graft was performed for primary flap closure. Free gingival graft was performed again at implant placement for the increase of attached keratinized mucosa. In second case, guided bone regeneration was performed on lower right first molar area, and implant was placed with free gingival graft. In third case, lower right molar area showed insufficient attached keratinized mucosa after implant placement with guided bone regeneration. When abutments were connected, free gingival graft with apically positioned flap was performed. Result: In these three cases, the zone of attached keratinized mucosa around dental implants was decreased after guided bone regeneration. And the increase of peri-implant attached keratinized mucosa could be obtained effectively by free gingival graft. Conclusion: Free gingival graft could be a effective treatment method increasing the zone of attached keratinized mucosa which was decreased after guided bone regeneration procedures.

• The International Journal of Costume Culture
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• 제2권1호
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• pp.10-20
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• 1999

This study investigated the usage of child hospital gowns to suggest a gown design suitable for child inpatients in Korea. The satisfaction on size suitability and design of child hospital gowns was surveyed among 219 child inpatients in 20 general hospitals. The most hospitals provided 2 to 4 different size pajamas for child inpatients. However, 53% of the subjects chose not to wear the uniform pants that the hospital provided and 28% did not wear the shirts. The reasons most often given for rejecting to wear the uniforms were unsuitable size (42.1%) and difficulty in taking on and off (26.2%). The dissatisfactory parts of hospital gowns were pants length (27.9%), sleeve length (19.6%), pants waist closure (16.9%), and neckline opening (11.9%). The preference in gown design for child inpatients varied by age (p〈0.5) and the styles that they had worn (p〈0.5). Significant differences for style preference were found in the opening of shirts or pants, pants waist closure type, and pants length. These results suggest that the hospital gowns for child inpatients need to reflect the wide diversity in their body size and preference in style.

• Clinical and Experimental Pediatrics
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• 제53권5호
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• pp.616-622
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• 2010

Enterovirus 71 (EV71) has been recognized as a frequent cause of epidemics of hand-foot-and-mouth disease (HFMD) associated with severe neurological symptoms. In the spring of 2009, HFMD was epidemic in Korea. Severe cases with complication, including death, have been reported and it has become a public health issue. Most symptomatic EV71 infections commonly result in HFMD or herpangina. These clinical manifestations can be associated with neurologic syndromes frequently. Neurologic syndromes observed in EV71 include meningitis, meningoencephalomyelitis, poliomyelitis-like paralytic disease, Guillain-Barr$\acute{e}$ syndrome, transverse myelitis, cerebellar ataxia, opsoclonus-myoclonus syndrome, benign intracranial hypertension, and brainstem encephalitis. Examinations for EV 71 were performed from the stools, respiratory secretion or CSF of the children by realtime PCR. Gene analysis showed that most of them were caused by EV71 subgenotype C4a which was prevalent in China, 2008. Public health measures including personal and environmental hygiene, must to target daycare centers, kindergartens, and schools where highly susceptible children congregate. To prevent the spread of infection, preschools where transmission persists for more than 2 incubation periods, have been recommended for closure, and trigger criteria for voluntary closure was instituted. During closure, operators are to thoroughly clean the centers before they are allowed to reopen. In addition, parents are advised to ensure that their children adopt a high standard of personal hygiene and to keep the infected child at home until full recovery. Because the outbreaks occur in a cyclical pattern, surveillance system to predict next outbreaks and adequate public health measures to control need to be planned for future. Control of EV71 epidemics through surveillance and public health intervention needs to be maintained in Korea. Future research should focus on understanding of EV71 virulence, identification of the receptor(s) for EV71, development of antiviral agents and development of vaccine.

• 대한구순구개열학회지
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• 제7권1호
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• pp.47-61
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• 2004

The closure of a wide alveolar cleft and fistula in cleft patients and the reconstruction of a maxillary dentoalveolar defect in bilateral cleft lip and palate (BCLP) patients are challenging for both orthodontists and oromaxillofacial surgeons. It is due to the difficulty in achieving complete closure by using local attached gingiva (palatal flap) and the great volume of bone required for the graft. In this article, the authors used bifocal distraction-compression osteosynthesis(BDCO) to create a segment of new alveolar bone and attached gingiva for the complete approximation of a wide alveolar cleft/fistula and the reconstruction of a maxillary dentoalveolar defect. Since the alveoli and gingivae on both ends of the cleft were approximated after BDCO, the need for extensive alveolar bone grafting was eliminated. It also could create new alveolar bone and gingiva for orthodontic tooth movement and implant.