• Restorative Dentistry and Endodontics
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• 제37권3호
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• pp.175-179
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• 2012

The aim of this study was to present a method for endodontic management of a maxillary first molar with unusual C-shaped morphology of the buccal root verified by cone-beam computed tomography (CBCT) images. This rare anatomical variation was confirmed using CBCT, and nonsurgical endodontic treatment was performed by meticulous evaluation of the pulpal floor. Posttreatment image revealed 3 independent canals in the buccal root obturated efficiently to the accepted lengths in all 3 canals. Our study describes a unique C-shaped variation of the root canal system in a maxillary first molar, involving the 3 buccal canals. In addition, our study highlights the usefulness of CBCT imaging for accurate diagnosis and management of this unusual canal morphology.

• International Journal of Reliability and Applications
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• 제10권1호
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• pp.1-15
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• 2009

Even though the impact of manufacturing quality to reliability is not considered much as well as that of design area, a major cause of an early failure of the product is known as manufacturing problem. This research applies two different types of neural network algorithms, the Back propagation (BP) algorithm and Learning Vector Quantization (LVQ) algorithm, to identify and classify the nonrandom variation pattern on the control chart based on knowledge-based diagnosis of dimensional variation. The performance and efficiency of both algorithms are evaluated to choose the better pattern recognition system for auto body assembly process. To analyze hundred percent of the data obtained by Optical Coordinate Measurement Machine (OCMM), this research considers an application in which individual observations rather than subsample means are used. A case study for analysis of OCMM data in underbody assembly process is presented to demonstrate the proposed knowledge-based pattern recognition system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 춘계학술대회 논문집 에너지변화시스템부문
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• pp.212-214
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• 2009

The polymer electrolyte membrane fuel cell(PEMFC) with the advantages of low-operating temperature, high current density, low cost and volume, fast start-up ability, and suitability for discontinuous operation becomes the most reasonable and attractive power system for transportation vehicle and micro-grid power plant in a household. 200W PEMFC(Polymer electrolyte membrane fuel cell) system applied to middle and small-scaled micro-grid power system was constructed by this study, then the electrical characteristics and diagnosis of the fuel cell were analyzed with thermal variation.

• 한국임상약학회지
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• 제22권2호
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• pp.103-112
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• 2012

Performance of coronary angiography for exact diagnosis and treatments of cardiovascular disease have been increased recently and it also brings increase of the contrast-induced nephropathy (CIN) referred from increasing use of radiological contrast agents. The variation of estimated glomerular filtration rate (eGFR) is an indicator of CIN, which is known to increase when renal function is decreased. Therefore, this study was to evaluate the affecting factors including concomitant drug on variation of eGFR of patients who underwent coronary angiography according to the conditions of renal function. Medical records of 66 patients were evaluated retrospectively and the patients underwent coronary angiography or angioplasty with nonionic and isotonic contrast media (iodixanol) at Chungnam national university hospital from 1 Jan 2008 to 30 Jul 2010. Patients group was divided into 2 groups; the patients in stages 3-4 chronic kidney disease (CKD) and the patients in stage 2 CKD. Each group was researched about the effect of concomitant drug and clinical characteristics on eGFR variation. The change of eGFR was compared among baseline and 2 or 3 day after coronary angiography. In results, the eGFR variation in group over age 75 was significantly decreased after radiological contrast agents exposure (p $$\leq_-$$ 0.05). The eGFR variation in anemia was significantly decreased after radiological contrast agents exposure in stage 2 CKD (p > 0.05). The eGFR variation in group under $HbA_{1c}$ 6.5% was significantly decreased after radiological contrast agents exposure in stages 3-4 CKD (p $$\leq_-$$ 0.05). The eGFR variation by taking statins, angiotensin converting enzyme inhibitors, calcium channel blockers and nitroglycerin was increased after radiological contrast agents exposure in stage 2 CKD (p $$\leq_-$$ 0.05). The eGFR variation by using of diuretics was significantly decreased after radiological contrast agents exposure in stages 3-4 CKD (p $$\leq_-$$ 0.05). The eGFR variation by taking statins, nitroglylcerin was increased after radiological contrast agents exposure in stages 3-4 CKD(p > 0.05). The eGFR variation in group over contrast dosage 150 ml was significantly decreased after radiological contrast agents exposure in stages 3-4 CKD (p $$\leq_-$$ 0.05). Therefore, when undergoing coronary angiography, contrast dosage should be minimized less than 150 ml, and diuretics should be restricted as possible in stages 3-4 CKD. Patients over age 75 require special attention to prevent CIN, and if patients undergo coronary angiography in stages 3-4 CKD, $HbA_{1c}$ is also requried to maintain below 6.5% to prevent CIN.

• 한국유체기계학회 논문집
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• 제9권6호
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• pp.35-44
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• 2006

Operation conditions of a reheat cycle gas turbine for a combined cycle power plant was analyzed. Based on measured performance parameters of the gas turbine, a performance analysis program predicted component characteristic parameters such as compressor air flow, compressor efficiency, efficiencies of both the high and low pressure turbines, and coolant flows. The predicted air flow and its variation with the inlet guide vane setting were sufficiently accurate. The compressor running characteristic in terms of the relations between air flow, pressure ratio and efficiency was presented. The variations of the efficiencies of both the high and low pressure turbines were also presented. Almost constant flow functions of both turbines were predicted. The current methodology and obtained data can be utilized for performance diagnosis.

• 한국정밀공학회지
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• 제15권4호
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• pp.105-110
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• 1998

In this study, statistical and neural network methods were used to recognize the cutting tool states. This system employed the tool dynamometer and cutting force signals which are processed from the tool dynamometer sensor using linear discriminent function. To learn the necessary input/output mapping for turning operation diagnosis, the weights and thresholds of the neural network were adjusted according to the error back propagation method during off-line training. The cutting conditions, cutting force ratios and statistical values(standard deviation, coefficient of variation) attained from the cutting force signals were used as the inputs to the neural network. Through the suggested neural network a cutting tool states may be successfully diagnosed.

• 한국정밀공학회지
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• 제11권5호
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• pp.110-123
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• 1994

The development of automatic production systems have required inteligent diagnostic and monitoring function to repair system failure and reduce production loss by the failure. In order to perform accurate functions of intelligent system, inferencing about total system failure and fault analysis due to each mechanical component failures are required. Also the solution about repair and maintenance can be suggested from these analysis results. As an essential component of mechanical system, a bearing system is investigated to define the failure behavior. The bearing failure is caused by lubricant system failure, metallurgical defficiency, mechanical condition(vibration, overloading, misalignment) and environmental effect. This study described roller bearing fault train due to stress variation and metallurgical defficiency from lubricant failure by using FTA.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 C
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• pp.1846-1849
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• 2002

A shorted-turn test was performed at the Sininchon combined cycle power plant on gas turbine generators. The test was conducted using a permanent flux probe and on-line diagnosis system. The flux probe installed in the generator air gap senses the field winding slot leakage flux and produces a voltage proportional to the rate of change of the flux. This pattern of flux variation is a signature unique to each field winding. We have also applied a voltage waveform analysis technique that can identify the pole location, slot number and number of shorted-turn with each slot.

• Korean Journal of Geomatics
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• 제4권1호
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• pp.17-22
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• 2004

It is very important to manage efficient data for safety and maintenance of those constructs. Estimation for structural safety can be evaluated by using data that surveys various structural durability and safety elements. so, it should be based on synthetic and efficient data that includes a variety of related safety elements obtained from a structure. It will subsequently be managed properly and economically. Accordingly, we will approach efficient maintenance management using a Geographic Information System (GIS) with data from structural-safety diagnosis and a Global Positioning System (GPS). In this study, we noted that by using the data that measures the factors (crack, incline, settlement etc.) of various structures as evaluate safety degree. And the horizontal coordinate variation/time of structure was monitored using the GPS easily.

• Asian Pacific Journal of Cancer Prevention
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• 제17권10호
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• pp.4723-4727
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• 2016

Background: There are substantial differences in the mortality rates of stomach cancer among the 47 prefectures in Japan, and Aomori prefecture is one of the most severely impacted. The aims of this study were to determine the incidence and mortality rates of stomach cancer in Aomori prefecture in comparison with Japan as a whole and cast light on reasons underlying variation. Methods: Data on stomach cancer cases were extracted from the Aomori Cancer Registry Database. Incidence rates for specific stages at the time of diagnosis were cited from Monitoring of Cancer Incidence in Japan, and mortality rates for stomach cancer in Aomori prefecture and the whole of Japan were obtained from Vital Statistics. Age-standardised incidence and mortality rates were calculated using the direct method. Results: The age-standardised incidence rate of stomach cancer in Aomori prefecture was higher than in the whole of Japan for males but lower for females. However, the age-standardised mortality rates were higher in Aomori prefecture in both sexes. The proportion of localised cancers was lower in Aomori prefecture than in the whole of Japan for most age groups. Conclusions: The lower rate for localised cancer suggests that higher age-standardised mortality rates are due to delays in diagnosis, despite an attendance rate for stomach cancer screening was higher in Aomori prefecture than in the whole of Japan. One plausible explanation for the failure of successful early detection might be poor quality control during screening implementation that impedes early detection.