• Journal of Navigation and Port Research
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• v.26 no.2
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• pp.215-220
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• 2002

In this paper, the 100 watt unit ower amplifier using temperature independent biasing for DTV (Digital Television) repeater application is designed and fabricated. The DC operation point of this unit power amplifier at temperature variation from $20^{\circ}C$ to $100^{\circ}C$ is fixed by active bias circuit. The variation of current consumption in the 100 watt unit power amplifier has an excellent characteristics of less than 0.6A. The implemented unit power amplifier has the gain over 12dB, the gain flatness of less than 0.5dB and input and output return, loss of than 15dB over the DTV repeater frequency range (470~806MHz). This unit power amplifier yields intermodulation distortion(IMD) of more than 32dBc at 2MHz offset, which satisfies the IMD at output power of 100 watt (50dBm).

• Journal of the Korea Organic Resources Recycling Association
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• v.25 no.3
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• pp.23-34
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• 2017

This study is conducted to find out the problem of the public food waste recycling facility and its improvement. By using an operation status analysis, an economic analysis was done to check up on its feasibility in comparison with an investment in the food waste recycling facility currently in use, thereby proposing the possible alternatives to prevent the national budgets form wasting with witless construction of the new facilities. As a result, it is considered necessary to come up with an effective plan for establishing the public resource facility, strengthen criteria for government subsidies being used up on the public resource facility, and enact an independent law of the food waste.

• Journal of Chest Surgery
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• v.23 no.6
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• pp.1191-1203
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• 1990

Pulmonary atresia and ventricular septal defect with major aortopulmonary collateral arteries [abbreviated as PA+VSD+MAPCA in the following] has limited the success of attempts at accurate diagnosis and complete surgical repair. From April 1986 to September 1990, 23 patients with PA+VSD+MAPCA among 96 patients of PA+VSD in Seoul National University Children’s Hospital were encountered. The group comprised 14 male and 9 female patients with ages ranging from 17 days to 177 months [mean 49.6 months]. We operated one stage total repair on good pulmonary artery sized two patients by R.E.V. [Reparation a l’etage ventriculaire] and Rastelli operation respectively. And the 11 patients who had independent MAPCAs and hypoplastic central pulmonary artery were dealt with unifocalization and modified Blalock-Taussig Shunt and followed by second stage repair in 3 patients later. We successfully had managed 7 patients whose MAPCAs could be ligated with modified Blalock-Taussig Shunt and followed by second stage repair in 3 patients with R.E.V or Rastelli operation. Recently, three obstruction after 11 unifocalization procedures made us to try palliative right ventricle-pulmonary artery conduit operation by Gore-Tex vascular graft interposition under cardiopulmonary bypass. And so we managed another 3 patients with these procedures for the purpose of pulmonary artery growth whose central pulmonary artery were severely hypoplastic. We experienced one death after second stage repair whose central pulmonary artery was created by 12mm Gore-Tex vascular graft and was unifocalized.

• Journal of Power Electronics
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• v.13 no.5
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• pp.806-813
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• 2013

This paper aims to compare the performance of three phase induction motor drives using Five Leg Inverter (FLI) and Three Leg Inverter (TLI) configurations. An Indirect Field Oriented Control (IFOC) method using a TLI is well established and incorporated for high performance speed drives in various industries. The FLI dual motor drive system on the other hand shows good workability in the independent control of two induction motor drives simultaneously. In this experiment, the IFOC method is utilized for both drive systems, and Space Vector Pulse Width Modulation (SVPWM) is used to generate pulses for both inverters. For the FLI, the Double Zero Sequence (DZS) Injection technique is used to generate the modulation signal. The complete experiment setup is done by using a DSpace 1103 controller board. The individual motor performances are analyzed using similar schemes, equipment setups and controller parameter values. The results show similar speed performance response capability between the single motor operation using a TLI system and the two motor operation using a FLI system based on the variable speed range either in forward or reverse operation. They also show similar load rejection abilities. However, the single motor with a TLI has a better power quality aspect such as ripple current and total harmonics distortion (THD).

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.9 no.3
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• pp.410-425
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• 1997

Buildings are mostly under part load conditions causing an inefficient system operation in terms of energy consumption. It is critical to operate building air-conditioning system with a scientific or optimal manner which minimizes energy consumption and maintains thermal comfort by matching building sensible and latent loads. Little research has been performed in developing general methodologies for the optimal operation of air-conditioning system. Based on this research motivation, system simulation program was developed by adopting various equipment operating strategies which are energy efficient especially for humidity control in summer. A numerical optimization technique was utilized to search optimal solution for multi-independent variables and then linked to the developed system simulation model within a mam program. The main goal of the study is to provide a systematic framework and guideline for the optimal operation of air-conditioning system focusing on air-side. For given cooling loads and ambient outdoor conditions the optimal operating strategies of a commercial building are determined by minimizing a constrained objective function by a nonlinear programming technique. Desired space setpoint conditions were found through evaluating the trade-offs between comfort and system power consumption. The results show that supply airflow rate and compressor fraction play main roles in the optimization process. It was found that variable setpoint optimization technique could produce lower indoor humidity level demanding less power consumption which will be benefits for building applications of humidity problem.

• Journal of Chest Surgery
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• v.22 no.1
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• pp.25-31
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• 1989

Forty-five patients, aged 16 months to 15.5 years mean 69 months, with a wide variety of cardiac malformations underwent the modified Fontan operation between Sep. 1986 to Aug. 1988. Nineteen patients had previously undergone palliative operations mainly modified B-T shunt. Twenty patients had a mean pulmonary artery pressure greater than 15 mmHg, with nine operative deaths. Thirteen patients had anomalies of systemic venous connection and seven patients had anomalies of pulmonary venous connection. There were eighteen patients under the age 4 years and fifteen of them survived [83.3%]. Eighteen patients had a pulmonary vascular resistance [PVR] more than 2.5U/m, and nine died [50%] whereas two of twenty-three with a PVR less than 2.5U/m died[8.6%]. PVR and anomalies of pulmonary venous connection had a significant influence on survival, but age and anomalies of systemic venous connection did not. Amount of pleural effusion drained postoperatively and PVR had positive linear correlation. Pulmonary artery pressure was not an independent predictor of outcome and pulmonary artery pressure alone should not contraindicate a Fontan procedure if PVR is low. In general, the Fontan operation should be done at a younger age less than 4 year to avoid ventricular dysfunction due to long-standing exposure to hypoxia.

• Journal of Digital Convergence
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• v.7 no.3
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• pp.35-47
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• 2009

The IS project is getting more and more complicated and large-scaled. Many researchers and practitioners are interested in the IS development methodologies, automated tools and techniques, TQM to decrease project failure, and to increase IS performance. But, in spite of such various efforts, the latest Standish Group's research indicates that the project scale is bulkier than $1{\sim}2$ year ago and IS development project's batting average falls from 34% to 28% at the same time, proceeded project is increased, and project discharged arrives to $15%{\sim}18%$. According to a research, success possibility increased by 37% after a year of PMO introduction, and increased sharply by 62% after 2 years and by 65% after S years. This research has a goal to survey how the PMO function and operation type affect the IS project performance in the financial industry. I determine nine independent variables and three dependent variables from previous researches. The results of this study are that the four core functions of PMO have relationship with project performance. But, technical support function does not relate with organization performance. Among the four core PMO operation types, three types have an effect on the IS project performance except the perfectionist type.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.848-854
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• 2009

Of the rapid development of modem civilization development is one of the IT industry. The Network is the root of the discrete industry. Most of the Protocol is used by LAN and the TCP / IP. Slowly in the railway operation of this Network is being applied. It also used to train and they are operated. The concept of the road, the Network TCP / IP using a non-Star structure of the Main Unit and the Bus Network is designed to structure consists of the Network. This structure is a simplified DATA. Data of complex operations is easy to feel the speed limit is. In addition, all devices must be independent to the operating system with the ability to manage the operation and stability in terms of exactly how the transmission of Data is gonna work pass. And transmission occurs in the middle of the Noise and the device is available to manage the power. Noise in the power of the railway to ensure the efficient transfer of Data is by blocking. Also, by presenting the entire system's operational safety should be guaranteed the safety of the railway.

• Journal of Fisheries and Marine Sciences Education
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• v.28 no.6
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• pp.1683-1694
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• 2016

This study aims to investigate perception of kindergarten directors regarding prerequisites for inclusive education and its improvement plans, and to establish basic data required for future implementation of inclusive education in kindergartens. This study was carried out oriented to 116 kindergarten directors and inquired into the differences in background characteristics of age, education level, operation career, major, special/inclusive education training and operation of inclusive classes, based on SPSS 1.5 for Window, independent sample t-test and Chi-square test. The research results of this study are as follows: Firstly, as for the perception of kindergarten directors as prerequisite of inclusive education, they show active supports for inclusive education and recognize that classes composed of the same age and same ability are the advisable forms of inclusive education. As for class operations, they perceive that inclusive classes based on small group activities and full inclusive classes are suitable. Moreover, as qualified teachers for inclusive classes, they manifest that teachers who completed special/inclusive education training are appropriate. Secondly, as for the perception of kindergarten directors regarding improvement plans for inclusive education, this study suggests that they prioritize the training operation regarding inclusive education oriented to general infants and parents. As for vitalization of inclusive education, they find that financial supports at the national level and administrative supports for facilities are indispensable.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.3B
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• pp.504-509
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• 2000

This paper presents a noble operation and maintenance system for the optical subscriber loops and its feasibility through several experiments. In this system, a broadband CW (Continuous Wave) light source I used as monitoring of testing signals. and a FGF(Fiber Grating Filter) of which reflective wavelength is independent, is inserted somewhere in each subscriber loop for the reflection of monitoring of testing signals. The propose of the system is quick decision. whether the loop is just fault or not. rather than detailed information of loop state. At present, most of operation and maintenance system for the optical subscriber loops adopts OTDR(optical time domain reflectometer) for testing function. the OTDR is useful for detailed test, but not adequate for simple test because of long testing time . And it is difficult to test PON network by using general OTDR that has a single-wavelength light source. Compared to using OTDR, the proposed system can afford to shorten testing time and to test PON network. Moreover, we can cut down the system cost by simplifying circuits of the optical light sources. Our results show that the proposed system operates well according to the purpose mentioned above.