• 한국초전도ㆍ저온공학회논문지
• /
• 제4권1호
• /
• pp.78-83
• /
• 2002

Since the KSTAR superconducting magnet structure should be maintained at a cryogenic temperature of about 4 K, even a small amount of heat might be a major cause of the temperature rise of the structure. The Joule heating by eddy currents induced in the magnet structure during the KSTAR operation was found to be a critical parameter for designing the cooling scheme of the magnet structure as well as defining the requirements of the refrigerator for the cryogenic system. Based on the Joule heating calculation, it was revealed that the bulk temperature rise of the magnet coil structure was less than 1 K. The local maximum temperature especially at the inboard leg of the TF coil structure increased as high as about 21 K for the plasma vertical disruption scenario. For the CS coil structure, the maximum temperature was obtained from the PF fast discharging scenario. This means that the vertical disruption and PF fast discharging scenarios are the major scenarios for the design of TF and CS coil structures, respectively. For the reference scenario, the location of maximum temperature spot changes according to the transient current variation of each PF coil.

• 한국병원경영학회지
• /
• 제5권1호
• /
• pp.156-175
• /
• 2000

This study was designed to find out the relations between the major investment decision-making behaviors and profitability of the hospital. A total of 57 hospitals were analyzed on this study. The major findings were as follows; 1. Among the types of the investment decision-making, major factors affecting the profitability were where the top management belongs among the defender, analyzer, prospector, and reactor type. Other factors were whether or not hospital analyzes which is more economical between the purchase by cash and lease of the medical equipment and whether or not hospital changes the decision before the actual investment. 2, Among the types of the investment decision-making, major factors affecting the financial structure and efficient operation of the assets were ranking of the priority and whether or not hospitals can get enough revenue and cash flow when hospitals have to borrow a big amount of fund from outside. 3. Among the financial indices regarding the financial stability, major factor affecting the profitability was fixed assets to long-tenn capital. Other factors affecting the financial structure and efficient operation of the assets were value added to medical equipment, normal profit to medical equipment, liability to total assets, current ratio, value added to payroll expenses. 4. Investment decision-making behaviors are partially influencing on the financial structure and efficient operation of the assets. However it was proved that the profitability was the most influencial factor than other factors related with the operation of the hospital. 5. To improve the irrational investment decision-making behaviors strategic management system should be introduced, and the top mamagement's investment decision-making style should be changed from reactor and analyser styles to prospector and reactor ones.

• Journal of Communications and Networks
• /
• 제2권1호
• /
• pp.5-17
• /
• 2000

cdma2000 offers several enhancement as compared to TIA/EIA-95, although it remains fully compatible with TIA/EIA-95 systems and allows for a smooth migration from one to the other-Major new capability include:1)connectivity to GSM-MAP in addition to IP and IS-41 networks; 2) new layering with new LAC and MAC architectures for improved service multiplexing and QoS management and efficient use of radio resource ;3) new bands and band widths of operation in support of various operator need and constraints, as well as desire for a smooth and progressive migration to cdma 2000; and 4) flexible channel structure in support of multiple services with various QoS and variable transmission rates at up to 1 Mbps per channel and 2 Mbps per user. Given the phenomenal success of wireless services and desire for higher rate wireless services. improved spectrum efficiency was a major design goal in the elaboration of cdma2000. Major capacity enhancing features include; 1) turbo coding for data transmission: 2)fast forward link power control :3) forward link transmit diversity; 4) support of directive antenna transmission techniques; 5) coherent reverse link structure; and 6) enhanced access channel operation. As users increasingly rely on their cell phone at work and at home for voice and data exchange, the stand-by time and operation-time are essential parameters that can influence customer's satisfaction and service utilization. Another major goal of cdma2000 was therefore to enable manufacturers to further optimize power utilization in the terminal. Major battery life enhancing features include; 1) improved reverse link performance (i.e., reduced transmit power per information bit; 2) new common channel structure and operation ;3) quick paging channel operation; 4) reverse link gated transmission ; and 5) new MAC stated for efficient and ubiquitous idle time idle time operation. this article provides additional details on those enhancements. The intent is not to duplicate the detailed cdma2000 radio access network specification, but rather to provide some background on the new features of cdma2000 and on the qualitative improvements as compared to the TIA/EIA-95 based systems. The article is focused on the physical layer structure and associated procedures. It therefore does not cover the MAC, LAC, radio resource management [1], or any other signaling protocols in any detail. We assume some familiarity with the basic CDMA concepts used in TIA/EIA-95.

• 중소기업연구
• /
• 제42권3호
• /
• pp.195-220
• /
• 2020

본 연구는 2002년부터 2019년까지 유가증권시장(KOSPI)과 코스닥시장(KOSDAQ)에 상장된 대기업 7,074개, 중소기업 2,394개를 대상으로 2011년을 기점으로 의무 도입된 한국채택국제회계기준(K-IFRS) 전후의 대주주지분율과 외국인 주주지분율이 레버리지비율에 미치는 영향을 실증분석 하였으며 분석결과는 다음과 같다. K-IFRS의 도입은 중소기업보다 대기업의 자본구조에 더 영향을 미친다고 할 수 있다. 유가증권시장과 코스닥시장에 상장된 대기업과 중소기업의 대주주지분율과 외국인주주 지분율은 레버리지비율에 유의한 영향을 미치는 것으로 나타났다. 대기업 및 중소기업 대주주는 부채의 사용을 재무위험으로 인식하여 레버리지비율을 감소시키는 것으로 나타났다. 또한 외국인주주는 K-IFRS 도입 여부와 상관없이 투자 위험을 낮추기 위해 부채사용을 재무위험으로 인식하고 레버리지비율을 감소시키는 방향으로 영향을 준다는 것을 알 수 있다.

• 한국정보통신학회:학술대회논문집
• /
• 한국해양정보통신학회 2005년도 춘계종합학술대회
• /
• pp.1026-1029
• /
• 2005

Grating 이 형성된 SiO$_2$ 기판상에 ZnO 박막을 graphoepitaxy 법으로 형성시킬 것을 제안하고 그 가능성을 고찰하였다. Si(100) 기판상에 노광작업(photolithograpy)을 이용하여 요철구조를 형성시킨 다음 자연산화를 시켜서 SiO$_2$ 기판을 제작하였고, 제작된 요철구조 위에 열증착 법으로 Zn 를 증착 시킨 후 이를 산화 시켜서 ZnO 박막을 형성 시켰다. 또한 열처리에 의한 결정성의 변화를 관찰하기 위하여 700 ${\sim}$ 900 $^{\circ}C$에서 열처리를 하였다. 제작된 시료는 Atomic Force Microscopy (AFM)로 표면을 관찰하였으며, Photoluminescence (PL) 을 이용하여 결정성의 변화를 관찰하였다.

• 동력기계공학회지
• /
• 제6권3호
• /
• pp.57-63
• /
• 2002

This paper describes the acoustic analysis of mid duty truck. The focus of the analysis is on structure borne engine noise with major contributions of 2nd order. It has been previously recognized that the noise contribution of each transfer path of structure borne noise can be varied with the charateristics of each mounts and vibro acoustic sensitivity of car body. The structure of car body will be split up into three major sub components, which are modeled separately, the engine, the frame and the cab. The acoustic performance is evaluated on three levels: engine to frame transfer, frame to cab transfer, and panel contribution from cab to driver. In order to perform these analyses, analytical models are created for the engine, frame, cab and acoustic cavity. The models are linked through a coupled fluid structure calculation, and through FRF Based Substructuring for the structural couplings. Based on the structural coupling calculations, a transfer path analysis is performed to identify the most important transfer paths. These paths are then the focussing points for applying modifications to the structure or the mount system. Finally, a number of modification are proposed and their effect is quantified.

• 한국공작기계학회논문집
• /
• 제15권1호
• /
• pp.39-48
• /
• 2006

In this paper, polymer composites based sandwich structures like beams and plates are optimised by using parametric study. The structures are composed of fibre reinforced composites for facial material and resin concrete and PVC foam for core materials. The stacking sequences and thickness of the composites are controlled as major parameters to find out the optimal condition for machine tool components. For the plate structure of machine tool bed composites-skined sandwich structure which has several ribs are proposed to enhance bending stiffnesses in two major directions at the same time. Dynamic robustness of a machine tool structure is investigated using modal analysis. From the results optimal configuration and materials for high precesion machine tools are proposed. And the plate was made of fiber reforced composite material and PVC foam.

• 한국정보통신학회:학술대회논문집
• /
• 한국해양정보통신학회 2005년도 춘계종합학술대회
• /
• pp.1042-1045
• /
• 2005

주기적인 구조를 갖는 Si (100) 기판을 이용하여 ZnO 박막을 graphoepitaxy 법으로 성장시키기 위한 가능성을 알아 보았다. photolithography에 의해 주기적 구조를 형성시켰으며, ZnO박막은 RF-sputter 법으로 증착하여 시료를 제작 하였다. 제작된 시료는 700$^{\circ}C$${\sim}$900$^{\circ}C$의 수증기 분위기에서 2시간동안 열처리 하여 열처리 온도에 대한 결정성의 변화를 고찰 하였다. 시료의 결정성은 Atomic Force Microscopy (AFM), PL(Photoluminescence)를 통해, 표면과 광학적 특성의 변화를 고찰하였다.

• 한국실내디자인학회:학술대회논문집
• /
• 한국실내디자인학회 2008년도 춘계학술발표대회 논문집
• /
• pp.209-213
• /
• 2008

This study is intended to propose a plan index that can be used in the early stage of a museum design based on theoretical review of a major space of a museum including its spatial division, functions and roles. The scope of the study includes functions and roles of circulation in a major space based on precedent studies. The spatial range is limited to a major space among exhibition spaces in a museum. This study analyzes overseas 14 museums. In terms of methodology, the study analyzes circulation in a descriptive way only In the focusing on floor plan and section composition. The results of this study are as follows. First, vertical elements should be critically considered in a circulation plan for functional performance of dimensional circulation distribution in a major space. Second, a plan by location of vertical and horizontal moving elements related to a major space affects a circulation relation more than a connection type between a major space and an exhibition area.

• 소음진동
• /
• 제9권4호
• /
• pp.822-827
• /
• 1999

The reduction of booming noise level and improvement of sound quality in the vehicle interior have been major fields of vehicle NVH for many years. In order to reduce the booming noise this paper proposed a system variable, which takes account of mode shapes and natural frequencies of the structural-acoustic system, measurement points and excitation frequency. By simplifying the system variable, the major contributors of panels inculding roof, roof lining, wind shield glasses, doors and floor to booming noise at a specific frequency was experimentally found. Also the relationships between structural modes of roof lining, one of the major contributors, and acoustic modes of compartment cavity were investigated from the viewpoint fo structure-borne noise. In addition, the roof lining was modified structurally by applying marble sponge to the gap between roof and roof lining. Asthe result of structural modification, the booming noise was reduce at target frequency.