• Journal of Chest Surgery
• /
• v.6 no.1
• /
• pp.51-56
• /
• 1973

This is one case report of successful resection of the aneurysm of the thoracic aorta, which det-ected by thoractomy unexpectedly, in the Department of Thoracic Surgery, Hanyang University Hospital. The patient was a 34 years old woman and subjective complaints was not related with the aneurysm. Chest film showed a small round hazy shadow in the left margin of the upper posterior mediastinum. A saccular aneurysm located on the descending thoracic aorta, 7cm distal to the left subclavian artery and arouse from the antero-lateral wall of the aorta. Excision of the saccular aneurysm was performed by cross clamping the descending aorta above and below the aneurysm, and then the defect of the aortic wall was closed by aortorrhaphy with continuous suture. Crossclamping time was required 15 minute. Histopathologically, the wall of the aneurysm consisted of all layers of the arterial wall, that is, intima, media and adventitia. Postoperative course was uneventful and aortogram showed good continuity of the blood flow of the entire aorta.

• Advances in biomechanics and applications
• /
• v.1 no.4
• /
• pp.227-237
• /
• 2014

The in vitro construction of osteo-articular large implants combining biomaterials and cells is of great interest since these tissues have limited regeneration capability. But the development of such organoids is particularly challenging, especially in the later time of the culture, when the extracellular matrix has almost filled the initial porous network. The fluid flow needed to efficiently perfuse the sample can then not be achieved using only the hydraulic driving force. In this paper, we investigate the interest of using an electric field to promote mass transport through the scaffold at the late stage of the culture. Based on the resolution of the electrokinetics equations, this study provides an estimation of the necessary electric driving force to reach a sufficient oxygen perfusion through the sample, thus analyzing the feasibility of this concept. The possible consequences of such electric fields on cellular activities are then discussed.

• Asia pacific journal of information systems
• /
• v.12 no.4
• /
• pp.77-99
• /
• 2002

This study compares avatar-based chatting and text-based chatting. The comparison focuses on the effect of different chatting methods on user perception such as flow, social presence, and media richness. Especially the effects of avatar are examined across varying task types-work-oriented and fun-oriented. To accomplish this objective, a laboratory experiment was conducted using 80 experienced subjects. The results indicate that avatar-based chatting was more playfulness than text-based chatting in general. However, the effects of chatting methods on user perception were quite different according to the task types. There was no significant difference between avatar-based chatting and text-based chatting in the fun-oriented task, but avatar-based chatting was perceived as a more playful, focused, telepresent, and social present method in the work-oriented task.

• Journal of Mechanical Science and Technology
• /
• v.15 no.3
• /
• pp.281-290
• /
• 2001

Particle contamination has been an ongoing problem affecting the reliability of the magnetic hard disk drives. Especially the recent use of MR head requires much tighter control of particle contamination due to thermal asperity (TA) phenomenon. In this study, the effects of slider air bearing surface design of TA reduction capability were investigated by manufacturing two types of sliders. Numerical methods were used to simulate the motion of particles in the head/media interface. Experiments were conducted to verify the results predicted by the numerical simulation. Drives were built and exposed to particle contamination using a particle injection chamber, which turned out to be a very simple and reliable particle generation method over conventional aerosol technique. Then the number of TA generated in the drives was recorded and compared. Also the contacts between slider and particles were investigated by acoustic emission study. It was found that a new ABS design, which has aerodynamic U-shaped rail and central flow passage, was beneficial in reducing the particle contamination on the slider.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.32 no.4
• /
• pp.249-254
• /
• 2008

Hydrodynamic performance test of a turbopump for a liquid rocket engine is carried out. The turbopump is composed of an oxidizer pump, a fuel pump and a turbine, and the two pumps are driven by the turbine. In the test, water is used for the pumps as working media and air is used for the turbine. Performance parameters of pumps and a turbine are drawn, and a power balance between the pumps and the turbine are calculated. The calculation shows a good power balance, which implies that the pump component tests, the turbine component test and the assembly test are reliably performed. At the starting period of the test, pressure rise-flow rate curve of a pump gradually approaches the ideal curve which could be obtained by very slow starting.

• Journal of Korea Multimedia Society
• /
• v.20 no.4
• /
• pp.721-729
• /
• 2017

This study examined the dramatic devices that the production team made for the studio progress in the survival music entertainment program of open narrative structure in which the audience participated through MBC 'The King of Mask Singer'. The reason for the need for dramatic equipment is that the studio Audience who participated in the process of the program crossed the situations of flow, selection, and enjoyment. As a result of the research, the production team of 'The King of Mask Singer' was found to have a device of time margin, lighting and background image, and role of MC in order to change the progress of the studio and that the participating audience naturally change their roles.

• Proceedings of the Korea Contents Association Conference
• /
• 2013.05a
• /
• pp.21-22
• /
• 2013

기존의 스마트 미디어(전자책) 저작 도구의 경우 현장 교육의 주체가 되는 일선 교사나 교육 전문인이 직접 스마트 미디어(전자책)를 출판하기 어렵다는 문제점이 있다. 본 논문에서는 콘텐츠 전문가, 일선교사 또는 일반 사용자들도 손쉽게 교육용 스마트 미디어(전자책)를 제작할 수 있고 다양한 스마트 디바이스에 호환 가능한 교육용 스마트 미디어 저작 도구 시스템을 제안한다. 제안하는 교육용 스마트 미디어 저작 도구 시스템은 WPF의 FlowDocument 기반의 문서 구조를 따른다.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.11 no.1
• /
• pp.414-435
• /
• 2017

As network adaptive streaming technology becomes increasingly common, transport protocol also becomes important in guaranteeing the quality of multimedia streaming. At the same time, because of the appearance of high-quality video such as Ultra High Definition (UHD), preventing buffering as well as preserving high quality while deploying a streaming service becomes important. The Internet Engineering Task Force recently published Multipath TCP (MPTCP). MPTCP improves the maximum transmission rate by simultaneously transmitting data over different paths with multiple TCP subflows. However, MPTCP cannot preserve high quality, because the MPTCP subflows slowly increase the transmission rate, and upon detecting a packet loss, drastically halve the transmission rate. In this paper, we propose a new multipath congestion control scheme for high-quality multimedia streaming. The proposed scheme preserves high quality of video by adaptively adjusting the increasing parameter of subflows according to the network status. The proposed scheme also increases network efficiency by providing load balancing and stability, and by supporting fairness with single-flow congestion control schemes.

• Journal of the Korean Society for Library and Information Science
• /
• v.3
• /
• pp.1-24
• /
• 1973

This paper is intended as a basic study in which the purpose is to provide understanding of the workings of man in relation to his information resources. Such understanding would prove of value in formulating the policies of an inoformation center serving the fields of science and technology. The information problem of the scientific community was assessed in the lights of the characteristics of the information (cumulativeness, currency versus obsolescence, volume versus redundancy, interrelationships, and foreign literature)and the flow of information and communication patterns covering the use of the variety of media and the information gathering habits of scientists. What can be done to ease the problem was sought in the improvements and innovations which call the attentions of the scientists and the technologists as producers and users of the information, of the professional organizations of various disciplines and of government.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2003.04a
• /
• pp.111-114
• /
• 2003

A new monitoring system has been developed for in-situ and realtime measurement of ozone transport in unsaturated porous media using a fiber optic sensor. The calibration of the fiber optic transflection dip probe (FOTDP) system was successfully carried out at various ozone concentrations using a column with length of 30 cm and diameter of 5 cm packed with glass beads, which don't react with gaseous ozone. The breakthrough curves (BTCs) of ozone was obtained by converting the normalized intensity into ozone concentration. The FOTDP system reflected the ideal transport phenomena of gas phase ozone at various flow rates. The FOTDP system worked well for in-situ monitoring of gas phase ozone at various water saturations and in presence of SOM. However, the FOTDP system did not measure the ozone concentration at more than 70% water saturation.