• 한국생산제조학회지
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• 제22권1호
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• pp.156-161
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• 2013

Recently, there has been a trend in the manufacturing process to focus on the durability of cable lug joint, especially in welding process due to the poor cable lug joint causes many troubles on products and workers during manufacturing process. Therefore development of high quality cable lug joint is important for successful manufacturing process and safety of worker. The Magnetic Pulse Forming(MPF) is one of efficient way to developed a high quality cable lug joint. In MPF, a high strain rate forming process, utilizes a high velocity oblique collision on the workpiece to be formed in required shape. The objective of this paper is to develop of high quality cable lug joint using electromagnetic force. To successfully accomplish this goal, section and electrical contact temperature of developed cable lug joint has been compared with various cable lug joint. Electrical contact temperature of developed cable lug joint by electromagnetic force is lower than manufactured cable lug joint by pressurer and hydraulic pressurer.

• 한국대기환경학회지
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• 제34권3호
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• pp.373-392
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• 2018

The emission of air pollutants in China has increased rapidly as its economy expanded over the last decades. The Chinese government has recently acknowledged the seriousness of the resulting air pollution and is trying to improve air quality in many ways. Here, we review the air quality control and management policies in China, one of our closest neighbors, because these policies may also influence the air quality in Korea. This study examined the recent policies on $PM_{2.5}$ reduction and analyzed the variation in air quality and air pollutant emissions in China. The ambient air quality and emission standards in China have been strengthened, based on China's Air Pollution Prevention and Control Action Plan of 2013. As a result, the annual mean concentration of $PM_{2.5}$ in 2015 in 74 large Chinese cities declined by 23.6% compared with 2013 values. Coal consumption in China also has been reduced by more than 10% per year since 2013. Furthermore, the laws controlling atmospheric emissions were revised again in 2016, and an air pollution forecasting and warning system was implemented to help manage air pollution problems. At present, the Chinese government is trying to evaluate its policies on $PM_{2.5}$ and find a new paradigm to mitigate ongoing $PM_{2.5}$ pollution. In this context, a joint study between Korea and China has been initiated to investigate the characteristics and sources of ambient $PM_{2.5}$ and to identify factors contributing to the high $PM_{2.5}$ concentrations in northeast China. We expect that this academic collaboration will benefit both countries in their search for new policies for $PM_{2.5}$ reduction.

• 융합정보논문지
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• 제12권3호
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• pp.204-213
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• 2022

본 연구는 대학생들의 구강건강수준에 영향을 미칠 수 있는 스트레스와 턱관절 장애를 조사하고 구강건강 관련 삶의 질과의 관련성을 파악하기 위해 실시하였다. 자료조사는 2021년 6월 3부터 2021년 7월 8일까지 대전 일부지역의 대학생 227명을 대상으로 실시하였으며, 독립표본 t검정, one-way ANOVA, Pearson 상관분석, 다중회귀분석을 이용하여 분석하였다. 조사결과, 턱관절 장애는 모든 스트레스 하위요인과 양의 상관성을 보였으며, 구강건강관련 삶의 질은 모든 스트레스 하위요인 및 턱관절 장애와 음의 상관성을 보였다. 또한, 구강건강관련 삶의 질에는 턱관절 장애와 대인 스트레스 및 가치관 스트레스가 영향을 미치는 것으로 나타났다. 이상의 결과를 토대로 대학생들의 스트레스와 턱관절 장애를 예방하여 구강건강관련 삶의 질을 향상시키는 체계적인 방안 모색이 요구된다.

• 기본간호학회지
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• 제11권3호
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• pp.281-291
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• 2004

Purpose: This study was done to investigate the effects of a rehabilitation program including Koryo Hand-Acupuncture on physical function, self-esteem, and quality of life of post-stroke elderly patients. Method: A nonequivalent control group pre-post test research design was used. Participants in the study were 44 post-stroke elderly people (22 in an experimental group, 22 in a control group) enrolled in a social welfare center and a hospital in K city. Data were collected from April 6 to August 20, 2004. The program consisted of Koryo Hand-Acupuncture, ROM exercise, health education and supportive care. The analyses were carried using frequencies, percentages, $x^2$-test, Fisher exact and t-test with SPSS 10.0. Results: The patients in the experimental group, who took part in the 10-weeks rehabilitation program including Koryo Hand-Acupuncture, had significant increases in shoulder joint flexion, shoulder joint abduction, elbow joint flexion, hip joint flexion, knee joint flexion, knee joint extension, flexibility, self-esteem and quality of life as compared to the control group. Conclusion: These results suggest that a rehabilitation program including Koryo Hand-Acupuncture may be utilized as an effective nursing program to improve physical function, self-esteem and quality of life for post-stroke elderly patients.

• 산업경영시스템학회지
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• 제16권28호
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• pp.115-124
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• 1993

In this study, as one of the methodologies for supplementing the deficiencies which are likely to happen in implementing the Joint Research and Development Project we suggest the Quality Assurance System applicable through analyzing the cases. In Quality Assurance System in implementing the Joint Research and Development Projects, the mutual review & approval method for the output by stages, technology interchange method, the frequent meeting among engineers, the test plan and the configuration management system should be provided.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 하계종합학술대회 논문집
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• pp.591-596
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• 1999

In this paper, we present a joint quality control system to be able to accurately control the relative picture quality among the video programs in terms of PSNR. The joint quality control system allows variable bit rate (VBR) for each video program to maintain the pre-determined relative picture quality among the aggregated video programs while keeping a constant sum of the bit rates for all programs to be transmitted over a single constant bit rate (CBR) channel. This is achieved by simultaneous controlling the video encoders to generate VBR video streams at the central controller. Furthermore we also suggest buffer regulation method based on the analysis of the constraints imposed by sender/receiver buffer sizes and total transmission rate. Through various simulation results, it is found that our quality control systems guarantee that the video buffers do not overflow and underflow and the quality control errors do not exceed 0.1 ㏈.

• 한국의료질향상학회지
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• 제14권1호
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• pp.29-34
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• 2008

• 품질경영학회지
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• 제47권3호
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• pp.437-451
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• 2019

Purpose: The purpose of this study is to improve the quality of the PGM system by improving the structure and production process of slip-ring rotary joint for radar. Methods: The improvement measures for each cause are established through failure analysis of broken items. Specifically, changing in the housing to improve the heating system. Changing the transportation method to prevent damage to equipment during transport. Changing work process of the attenuator ring to prevent damage. etc. Results: The results of this study are as follows; improving the heating system reduces heat generated by the attenuator by about 7 degrees and obtain additional temperature margins. Reduction of defect rate because of adding X-band rotary joint run-out measurement test, ESS of slip-ring rotary joint and Transportation improvement(reinforced flight boxes, tube protection, etc). Getting stable VSWR values by improving work process of attenuator overheating due to a bad bonding process. Conclusion: Through this study, improvements were made to slip-ring rotary joint that failed repeatedly for various reasons. As a result of the application of the improvements, the same fault does not occur until now, so we can see that the quality of PGM has improved.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 1995년도 특별강연 및 추계학술발표 개요집
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• pp.3-20
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• 1995

Development of Real-Time Quality Evaluation of Friction Welding by Acousitc Emission : Report 1 ABSTRACT : According as the friction welding has been increasingly applied in manufacturing various machine components because of its significant economic and technical advantages, one of the important concerns is the reliable quality monitoring method for a good weld quality with both joint strength and toughness in the process of its production. However no reliable nondestructive test method is available at present to determine the weld quality particularly in process of production. So this paper presents an experimental examination and quantitative analysis for the real-time evaluation of friction weld quality by acoustic emission, as a new approach which attempts finally to develop an on-line quality monitoring system design for friction welds using AE techniques. As one of the important results, it was confirmed, through this study, that AE techniques can be reliably applied to evaluating the friction weld qualify with 100% joint strength, as the cumulative AE counts occurring during welding period were quantitatively correlated with reliability at 95% confidence level to the joint strength of welds. Real-Time Evaluation of Automatic Production Quality Control for Friction Welding Machine : Report 2 Abstract : Both in-process quality control and high reliability of the weld is one of the major concerns in applying friction welding to the economical and qualified mass-production. No reliable nondestructive monitoring method is available at present to determine the real-time evaluation of automatic production quality control for friction welding machine. This paper, so that, presents the experimental examinations and statistical quantitative analysis of the correlation between the initial cumulative counts of acoustic emission(AE) occurring during plastic deformation period of the welding and the tensile strength of the welded joints as well as the various welding variables, as a new approach which attempts finally to develop an on-line (or real-time) quality monitoring system and a program for the process of real-time friction welding quality evaluation by initial AE cumulative counts. As one of the important results, it was well confirmed that the initial AE cumulative counts were quantitatively and cubically correlated with reliability of 95% confidence level to the joint strength of the welds, bar-to-bar (SCM4 to SUM31, SCM4 to SUM24L) and that an AE technique using initial AE counts can be reliably applied to real-time strength evaluation of the welded joints, and that such a program of the system was well developed resulting in practical possibility of real-time quality control more than 100% joint efficiency showing good weld with no micro-structural defects.

• 한국정밀공학회지
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• 제23권7호
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• pp.59-66
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• 2006

In laser welding, automatic seam tracking is important to adjust the laser head position in real time as it moves along the seam. Also if the joint gap is occurred, filling the missing material into the joint gap is necessary to prevent welding defects and bad welding quality. In general, the joint gap width is not constant along the seam due to a variety of reason. So it is essential to control the filler wire speed into the joint gap to acquire good welding quality. This paper describes an intelligent filler wire feeding device which can control 3-dimensional seam tracking and the filler wire speed by measuring the gap position and the joint gap width in laser welding. We call this device as Smart Micro Control system(SMC). To achieve this objective, we assessed weld quality in 2mm sheets of A16061 which had various gap width by using the developed device. From the experimental results, It was found the possibility that the developed device could be used in welding various 3-dimensional structures.