• 전자공학회논문지D
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• 제34D권9호
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• pp.1-6
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• 1997

A transmission type phase shift attenuator has a poor reflection characteristics at an output port. And that is controlled by the current, its dynamic rnage decreases due to the current limitation. In this paper, to avoid such disadvantages, a reflection type low phase shift attenuator has been designed and measured. As a result, at a center frequency (1855MHz), the sreflection type low pahse shift attenuator has an attenuation of 30dB, within the limit of 3 phase shift and less than -17dB reflection characteristics at both input and output ports. And it demonstrates the peformance of the reflection type low phase shift attenuator is better than the transmission type phase shift attenuator with the same measurement specifications.

• 전자공학회논문지A
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• 제29A권4호
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• pp.49-57
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• 1992

Tungsten film was deposited on the TiN surface in a low pressure chemical vapor deposition reactor and chemical reaction mechanism between TiN surface and ($WF_{6}\;and\;SiH_{4}$ was studied. Interaction of ($WF_{6}\;or\;SiH_{4}$ with TiN surface and tungsten was deposited more easily. $WF_6$ reacted with TiN activated the TiN surface to form volatile TiF_4$ and tungsten nuclei were formed. ($SiH_{4}$ was dissociated on the TiN surface to form silicon nuclei. From RBS and AES analysis, we could not detect the impurities(such as Si or TiF$_x$)at the interface between tungsten and TiN. The adhesion at the W/TiN interface became poor when the deposition temperature was below 275$^{\circ}C$.

• 한국농공학회지
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• 제40권6호
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• pp.37-45
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• 1998

A survey was conducted to get information on the utilization of irrigation systems for greenhoyses farming. Three regions were selected which represent geographical chatacteristics such as neighboring urban area, flat-field area, and mountainous area. The number of greenhouses farms interviewed was 432 in total. The contents of the survey consisted of general characteristics of greenhouse farmers, the size and location of greenhouses, cultuvated crops, irrigation method, irrigation scheduling, and irrigation automation. The analysis of the surveyed data showed that greenhouse farmers did not take technical assistances. Proper criteria or guidelines for selection and operation of irrigation systems were not available. Irrigation systems were operated by hand. Irrigation scheduling were executed by farmer's experience. Maintenance of irrigation systems in general were poor. Development of economically reasonable irrigation system is of importance.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 하계종합학술대회 논문집(4)
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• pp.255-258
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• 2002

Recently, Digital TV viewer have been replacing cathode ray tubes (CRT) with Plasma display panel(PDP). But the chromaticity of the primaries are dependent on RGB input signals. And the colorimetry of PDP changes with gray scale and has a poor performance in color reproduction. In this paper we propose the enhanced algorithm of color reproduction considering nonlinear gamut mapping algorithm. In order to test performance of this algorithm we use the sample colors. As a result of experiments, it was confirmed that the color difference of the digital PDP using the proposed algorithm was considerably reduced.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.57-58
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• 2006

Ad hoc MAC protocols using directional antennas can be used to improve the network capacity by improving spatial reuse. But, the directional MAC protocols have the problem of deafness and have a poor throughput performance. The dual-channel DMAC protocol has been proposed to mitigate deafness and improve spatial reuse. In this paper, we propose a dual-channel DMAC protocol using the omnidirectional antenna for an out-of-band tone and directional antennas for control/data channels. In the proposed MAC protocol, an omnidirectional out-of-band tone mitigates deafness and directional antennas used in control/data channels improve spatial reuse and reduce interference packets. The throughput performance of the proposed MAC protocol is confirmed by computer simulations using Qualnet ver. 3.8 simulator.

• 산업경영시스템학회지
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• 제28권1호
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• pp.72-83
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• 2005

Recall aims to remove the products hazardous to consumers or users from the commerce. However, a recall with a poor decision making procedure could results in disaster to corporations. Therefore, recall managers should establish a proper recall plan in advance to minimize the damage to business. The purpose of the study is to propose a computerized recall management system(RMSys) to handle recall process systematically and timely manners. RMSys, a recall decision-making procedures software, consists of two different modules such as recall decision-making module and recall procedure module. RMSys on the basis of the world wide web is designed to be compatible to ERP(Enterprise Resources Panning). RMSys could play a role as a management support system to help the corporations recall the hazardous products with minimum efforts.

• Communications for Statistical Applications and Methods
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• 제10권2호
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• pp.585-594
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• 2003

It has been generally recognized that conventional binomial or Poisson model provides poor fits to the actual correlated binary data due to the extra-binomial variation. A number of generalized statistical models have been proposed to account for this additional variation. Among them, beta-binomial, correlated-binomial, and modified-binomial models are binomial-related models which are frequently used in modeling the sum of n correlated binary data. In many situations, it is reasonable to assume that n correlated binary data are exchangeable, which is a special case of correlated binary data. The sum of n exchangeable correlated binary data is modeled relatively well when the above three binomial-related models are applied. But the estimation results of correlation coefficient turn to be quite different. Hence, it is important to identify which model provides better estimates of model parameters(success probability, correlation coefficient). For this purpose, a small-scale simulation study is performed to compare the behavior of above three models.

• 한국산업융합학회 논문집
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• 제18권2호
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• pp.119-128
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• 2015

In this paper, we propose a new motion control technology to design robust control system of industrial robot. The system modeling of robotic manipulation tasks with constraints is presented, and the control architecture for unconstrained and constrained motion system with parametric uncertainties is synthesized. The optimal reference of robot manipulator is generated by the reference controller as a discrete state system and the control behavior of constrained system which has poor modeling information and time-invariant constraint function is improved motion control system is successfully evaluated by experiment to the desired tasks.

• Journal of Chest Surgery
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• 제6권2호
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• pp.165-170
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• 1973

The selection and treatment with resection and drainage for patients with emphysematous bullae is discussed with reference to two patients recently. One case with bilateral multiple bullous emphysema resulting tension pneumothorax due to rupture of the bullae on right, 47 year old man with pulmonary tuberculosis history for 16 years, was treated with resection of the bullae on right including upper lobectomy and c!osed rhoracostomy drainage on left for another spontaneous pneumothorax, and result was excellent for 6 month after discharge. Another 53 year old man with giant tension air cysts occupying right whole lung field and shifting mediastinum to the left was treated with right under water sealed closed thoracostomy drainage for 7 days in vain, and resection was not performed for his poor respiratory function and general condition. The most useful preoperarive information was obtained from a study of the plain chest radiogram and the surgical procedure of choice was obliteration of the bullae at thoracotomy.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 2001년도 추계학술대회 및 정기총회
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• pp.41-76
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• 2001

Rheumatoid arthritis is an incurable chronic inflammatory and destructive arthopathy that affects 1% of the population world-wide. It has substantial personal, social and economic costs. The long-term prognosis is poor: 80 percent of affected patients will become disabled within 20 years after onset of disease. Medical costs of rheumatoid arthritis average ∼$ 6000 (US) per patient (1), Current antirheumatic drugs have limited efficacy and many side effects and more importantly they do not improve the long-term prognosis of rheumatoid arthritis (2). After a decade of few notable advances in therapy, several biological response modifiers that target pathophysiological processes in the disease have now emerged in the clinic. These new drugs are termed biological agents, and although information about their use in the clinic is still limited to short term treatment, they appear to have the ability to modify disease progress. In addition, COX-2 selective agents have now been approved that have comparable efficacy with standard NSAIDs, but fewer gastrointestinal side effects (3). Thus today many more therapeutic options are suddenly open to patients that even five years ago had little hope of relief from chronic pain and inflammation.