• Journal of Chest Surgery
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• v.38 no.7 s.252
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• pp.483-488
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• 2005

Aortic valve-sparing procedures could reduce valve-related morbidity, but may increase operative risks; therefore, these procedures could not be performed routinely. We attempted to find out the early results while focusing on the operative risks associated with these procedures in our hospital. Material and Method: From May 1996 to July 2003, 26 patients underwent these procedures including 15 patients with Marfan syndrome and 1 patient with Behcet disease. There were 17 men and 9 women with mean age of $37.9\pm19.2$ years (range: 6 months-74 years). Ten patients had ascending aortic dissection, 18 patients had more than moderate degree of aortic valve insufficiency (AI). Two types of valve-sparing procedures were performed: valve reimplantation in 14 and root remodeling in 12 patients. Associated procedures were performed as follows: aortic valve plasty in 6, mitral valve plasty in 5, hemi-arch replacement in 4, total arch replacement in 2, coronary artery bypass surgery in 1 and Maze procedure in 1 patient(s). Result: In four patients, valve-sparing procedures were converted to Bentall procedures during operation. Including these patients, there was no operative deaths, 3 patients underwent re-operation due to bleeding, 1 patient had permanent pacemaker. The median duration of ICU stay was 45.5 hours, the median duration of hospital stay was 10.5 days. In 22 patients excluding 4 converted patients, intraoperative transesophageal echocardiogram (TEE) showed less than mild degree of AI in all except one who had not received intra-operative TEE in the beginning and showed moderate degree of AI at discharge. The mean duration of follow-up was $21.2\pm27.4$ months. All patients were alive except one who died during other departmental surgery. In 3 patients, more than moderate degree of AI was recurred, but there were no reoperation. Conclusion: Aortic valve-sparing procedures could be performed relatively safely in selected patients who had annuloaortic ectasia.

• Proceedings of the Korean Society for Quality Management Conference
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• 2010.04a
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• pp.283-290
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• 2010

This paper suggest that the derivation of good and practical ideas is important for the successful use of Kano model. Wish List, Bug List and Forced Connection Method as well as Brainstorming were applied to PMP(Portable Multimedia Player) in order to derive customer attributes. Wish List and Bug List are variants of Brainstorming, which are contrary to each other. Forced Connection Method is designed to bring about bisociation which is a typical characteristic of creative thinking.

• International Journal of Automotive Technology
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• v.6 no.2
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• pp.125-131
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• 2005

This article reports the experimental and numerical results for free sprays under ultra-high injection pressure conditions to give us better understandings of spray characteristics and also to make clear a limit pressure condition in diesel sprays. The high pressure injection system developed in this work is devised to reach ultra-high pressure conditions in the range from 150 MPa to 355 MPa. The free spray injected from a single nozzle injector is visualized by the Schlieren technique and the high speed camera. In particular, it is found that the shock waves are present and propagated along the edge of spray in the downstream direction. The measured spray penetration length increases gradually with the injection pressure, but its increasing rate is decreased as the injection pressure increases. The Sauter mean diameter is also no longer augmented for the injection pressures higher than 300 MPa. In addition, the three­dimensional numerical simulations are conducted for comparing the measurements with the predictions based on two different breakup models. The TAB model results show better agreements with experimental data than the WAVE model under ultra-high injection pressure conductions. Moreover, the simulation results show that the gas-phase pressure increases substantially in the vicinity of the spray tip region. It supports the experimental observation that the shock waves are formed at the front of spray tip and are propagated downstream.

• Journal of the Korea Safety Management & Science
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• v.10 no.3
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• pp.267-274
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• 2008

This paper reports generating creative ideas based on customer needs using Kano Model and Importance-Differentiation Matrix (I-D Matrix). Nowadays, every customer demands creative ideas on product innovations in order to be satisfied her needs. However, most existing methods are limited to get creative ideas that reflect customer needs. Any creative ideas that do not fully reflect customer needs are obviously more difficult to succeed in the market than those that reflect customer needs. This paper distinguishes each quality elements the customer needs in terms of Kano Model. And it presents the effective ways of generating creative ideas by I-D Matrix in order to overcome current uppermost limits.

• Journal of Korean Society for Quality Management
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• v.39 no.2
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• pp.305-312
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• 2011

Kano model has been widely used to identify and classify customer attributes of a product or a service. The first step of Kano model application is the derivation of customer attributes, and brainstorming has been used conventionally for the purpose. A typical advantage of brainstorming is to get many ideas in a relatively short period, but the practicability of the derived ideas are known to be not so good. The derivation of good and practical ideas is important for the successful use of Kano model. Wish list, bug list and forced connection method as well as brainstorming were applied to PMP(Portable Multimedia Player) in order to derive customer attributes. To compare the idea generation methods, the derived attributes are classified and compared using Kano model.

• Journal of Korean Society for Quality Management
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• v.38 no.2
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• pp.161-170
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• 2010

Diffusion of e-learning has been accelerated according as the convenience and effectiveness have been increased rapidly due to the advancement of information technology. However, there has been few studies on systematic evaluation of its performance. SERVQUAL model was applied to evaluate the service quality of a 100% on-line lecture opened in a major Korean university. Two classes, one for 71 undergraduate students, the other for 79 graduate students, were opened for the lecture. The gaps between the expected service and the perceived service scores were compared with respect to sex, age, and e-learning experience. Although the gap score of male and female students were not different significantly, the gap scores among the other comparative groups were different. The perceived score of the older group with more than thirty ages was lower than that of the younger group. It seems that the older group evaluated the score based on the practical use of the subject since they are part-time students with jobs. Also, the perceived score of the group with previous e-learning experience was higher than that of the group with no e-learning experience. It seems that the experienced group evaluated it compared with the previous e-learning satisfaction. As it might be expected, the groups with higher perceived scores had stronger intention to recommend the e-learning lecture to other students.

• Proceedings of the KIEE Conference
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• 1995.07a
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• pp.137-140
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• 1995

This paper describes the test results of magnetic field distributions of superconducting MRI magnet in an insert dewar. To get a very high homogeneous magnetic field, various shim coils are installed besides the main magnet. The operating currents of each shim coils are obtained from the exact measurements of the magnetic field. In this paper, we report the test results of the magnetic field distribution measurements with various shim coils.

• Korean Journal of Heritage: History & Science
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• v.45 no.3
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• pp.238-261
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• 2012

This research was carried out about the Bansu which surrounded the Sunggyungwan(成均館), national university in the Joseon Dynasty to get the main characteristics of the landscape at Korean traditional school campus by analyzing cultural meaning and historical origin. The earliest record about the Bansu was in "The Book of Odes(詩經)" as Bansu was the water flowing near the Ban palace(泮宮). But, in the following time, Bansu has become the symbol of the school which was built by the feudal lords and one of very important elements in the temple-school(廟學) landscape. The Bansu of Sunggyungwan at Joseon Dynasty was the streams flowing at the east and west of the school campus and get together at the south. Sunggyungwan was located in the sacred place which followed the special organization of Bansu at the beginning of the Joseon Dynasty. And, Bansu in Joseon Dynasty was influenced by the Bansu in Song Dynasty(宋), but it was different from the Bansu in Ming and Qing Dynasty which has been formulated as the halfround pond in front of the school. This research tried to find the reason why in the Josenon Dynasty the stream flowing around the school was regarded as the Bansu. Bansu was also regarded as an important element in the public school, Hyanggyo(鄕校) and the private Seowon(書院). According to this research, the streams which flows around the Seowon or the Hyanggyo were found as called Bansu. Water stream around the Hyanggyo and the Seowon in the Joseon Dynasty has to be reconsidered under the deep research on the organization of Ban-su.