• Journal of Chest Surgery
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• v.11 no.2
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• pp.199-212
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• 1978

One hundred cases of cardiac valve replacement were done at this Department in the period from June 1968 to May 15, 1978. Seventy-one cases of mitral, 12 aortic, and one tricuspd valve were replaced. There were 16 cases of double valve replacement, 10 aortic with mitral and 6 mitral with tricuspid valve replacement. Prosthetic valves-Beall, Bjoerk-Shiley, Starr-Edwards, Wada-Cutter, Magovern-Cromie, and Smeloff-Cutter valves-were used. But in recent years bioprosthetic valves-Hancock, Carpentier-Edwards, and Angell-Shiley valves-were used mainly due to the difficulties of postoperative anticoagulation, especially for the rural Korean patients. Over all operative mortality was 2896, 26.2% for single and 37.5% for double valve replacement cases. There were 4 postoperative thrombo-embolism cases with 2 deaths. Four postoperative subacute bacterial endocardities cases with 2 deaths were noted. Three cases of postoperative congestive heart failure succumbed. Two cases of peri valvular leakage, one of which needs reopration, were found. There were 28 operative and 9 late deaths, leaving 63 long-tel m survivors, who showed marked improvements.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.11
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• pp.987-994
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• 2000

A Linear Pulse Motor (LPM) is a direct drive motor that has good performance in terms of accuracy, velocity and acceleration compared to the conventional rotating system with toothed belts and ball screws. However, since an LPM needs supporting devices which maintain constant air-gap and has strong nonlinearity caused by leakage magnetic flux, friction and cogging, etc., there are many difficulties in improvement on accuracy with conventional control theory. Moreover, when designing the position controller of LPM, the modeling error and load variations has not been considered. In order to compensate these components, the neural network with conventional feedback controller is introduced. This neural network of feedback error learning type changes the current commands to improve position accuracy. As a result of experiments, we observes that more accurate position control is possible compared to conventional controller.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.8
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• pp.4495-4499
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• 2013

Morinda citrifolia, also known as Great Morinda, Indian Mulberry, or Noni, is a plant belonging to the family Rubiaceae. A number of major chemical compounds have been identified in the leaves, roots, and fruits of the Noni plant. The fruit juice is in high demand in alternative medicine for different kinds for illnesses such as arthritis, diabetes, high blood pressure, muscle ached and pains, menstrual difficulties, headache, heart diseases, AIDS, gastric ulcer, sprains, mental depression, senility, poor digestion, arteriosclerosis, blood vessel problems, and drug addiction. Several studies have also demonstrated anti-inflammatory, antioxidant and apoptosis-inducing effects of Noni in various cancers. Based on a toxicological assessment, Noni juice was considered as safe. Though a large number of in vitro, and, to a certain extent, in vivo studies demonstrated a range of potentially beneficial effects, clinical data are essentially lacking. To what extent the findings from experimental pharmacological studies are of potential clinical relevance is not clear at present and this question needs to be explored in detail before an recommendations can be made.

• Journal of Korean Academy of Nursing Administration
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• v.19 no.2
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• pp.227-238
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• 2013

Purpose: The purpose of this study was to explore the lived experiences of new graduate nurses in personal life and in clinical setting during their first year. Methods: Eleven new graduate nurses were interviewed and the data were analyzed using the Giorgi's phenomenological method. Results: The main results of this research were negative experiences such as poor nursing skills, inability to enjoy personal life, physical exhaustion and health problems, and uncertainty of nursing values. On the other hand, there were some positive aspects on their minds: adjustmental/developmental needs, sense of responsibility, receptive capability, and proficiency with their work. They gradually found themselves being endured and changing to adapt. Conclusion: Transition from students to staff nurses is a very stressful experience for new graduate nurses. It may negatively affect their personal lives as well. However they tried to keep themselves positive to overcome their difficulties. It is necessary for them to be given time, a systematic program, and a supportive environment to adapt.

• Journal of the Korean Institute of Landscape Architecture International Edition
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• no.2
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• pp.39-44
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• 2004

The city environment construction of China is facing many difficulties and challenges. Through the concerted exploration in the recent years to find the way of improving city environment that is suitable to Chinese situation, the result is to plan and construct a complete green space system, supplement the defective conditions by the system's superiority and produce the integrated effectiveness. The article dissertates on the composition of green space system, some important issues in the planning and construction and corresponding measures. The fact illustrates the effectiveness of city green space system in solving the city environment problems. However it needs some research and continues improving.

• Journal of Korean Elementary Science Education
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• v.38 no.1
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• pp.102-115
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• 2019

This study investigated how elementary school teachers reconstruct science curriculum and how they perceive about their experiences. In-depth interviews were conducted with four elementary school teachers who had experience in restructuring science curriculum. Two distinct types of reconstruction were found; restructuring within the subject and integrating between subjects. The teachers who were restructuring science curriculum from personal needs usually substitute, delete, add some contents or activities and change the order of unit within science subject. In contrast, the teachers who were participating in research school usually integrated science with other subjects, developing a new unit or project. The latter recognized the need of teachers' reconstruction of science curriculum more strongly and the importance of teacher's voluntary learning community in implementing the reconstruction. Though they had some difficulties in identifying students' interests and level of understanding and lack of time, all teachers valued curriculum reconstruction by relating it to teacher professional development, identity as a teacher, and job consciousness.

• Electronics and Telecommunications Trends
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• v.38 no.5
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• pp.81-89
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• 2023

Software is becoming increasingly important, accounting for more than 90% of the innovations in the automotive industry nowadays. In fact, the share of software in the automotive market is estimated to be around 40%. Accordingly, the shift from hardware- to software-centric vehicles, represented by software-defined vehicles (SDVs), will drastically reorganize the automotive industry ecosystem. This article presents challenges that the automotive ecosystem needs to solve and measures that each participant in the ecosystem should adopt in line with the transition to SDVs in the automotive industry. It is expected that tier-1 suppliers will face difficulties due to the decoupling of software and hardware, and OEMs will need to strengthen cooperation to share costs and shorten development periods to cope with the huge cost of software development.

• Journal of Theoretical and Applied Mechanics
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• v.3 no.1
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• pp.1-15
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• 2002

Reduction methods for large structural systems have been reviewed. Mai emphasis is put on the dynamic reduction. Recently, the computing resources and technologies have been expanded so fast that the huge matrices Invoked In the analysis of structural system can be processed without serious difficulties. For most users, however, the computer facilities are limited and the system reductions in some forms are required. The reduction procedure in static problems is simple and straightforward. The major task is the book-keeping in computations. In dynamic problems and structural optimization. however. the problem is much more complicated. The problem is, in general, nonlinear and hence the exact solution is not available. Therefore, approximate solutions are sought in an iterative manner. A proper convergence criterion needs to be employed in order to get an accurate solution efficiently. Several research works have been reported fer the structural optimization combined with system reductions.

• Journal of Distribution Science
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• v.2 no.2
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• pp.109-118
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• 2004

The number of business incubator (BI), introduced in Korea in the early 90's, has grown rapidly in the last 10 years, reaching 342 by 2002. Most of the incubator was supported financially by the Small and Medium Business Administration (SMBA), and 83% of them are run by college or university. To develop successful plans for college business incubator, we studied the relationship between a college incubator and its tenants through a systematic questionnaire, and compared royalty systems of four college BI's. It was found out that the tenants wants more flexible advisor system and closer relationship with the professors to solve the technical difficulties. The royalty system is important for BI's to survive without the financial assistance from the government, but the royalty systems of the four college BI's studied in this report have some practical shortcomings and needs amendments.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.12
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• pp.55-61
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• 1998

Recently, the needs of machining technologies of very small parts have been increasing with advent of micro-revolution. These technologies have mostly used the method applied to semi-conductor production process such as LIGA, etc. But they have serious difficulties to settle down in terms of workpiece materials, machining thickness, 3-dimensional structure. Therefore. mciro-machining technology using EDM(Electrical Discharge Machining) was proposed. It is very difficult to machine the micro-parts (microshaft, microhole) using conventional machining. Micro-machining using BDM can machine the micro-parts easily because it requires little machining force. This MEDM(Micro-EDM) need the capabilities to move a electrode and control a discharge energy precisely, and the gap control strategy to maintain the optimal discharge condition is necessary. Therefore, in this study, the new EDM machine with high precision motion stage and high-performance EDM device was developed. Using this MEDM machine, we have machined microshaft and microhole with various shapes and sizes.