• 한국해양공학회지
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• 제10권1호
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• pp.36-46
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• 1996

This paper deals with determinig the proper friction welding condition and analyzing various mechanical properties of friction welded joints of sintered carbide tool materials(K20, P25, and SKDX5 for the blade part of drill or press punch) to alloy steel (SKH4, SCM440 for the shank part of drill or press punch), the alloy steel to aluminum(A6061 for the interlayer material between the blade part and the shank) and sintered carbide tool materials to alumminum. And also acoustic emission test will be carried out during fiction welding to evaluate the weld quality.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1999년도 추계학술대회 논문집 - 한국공작기계학회
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• pp.485-491
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• 1999

A burr is formed in every corner of parts as a result of machining, which produces undesirable edge geometry and influence deeply to surface quality of workpiece. Therefore these burrs must be removed certainly. The cost of removing these burrs is directly proportional to their size. Burrs have been among the most troublesome obstruction to high productivity and automation of machining processes. The proper selection of cutting condition and tool geometry will be helpful to reduce the occurrence of burrs. In paper will observe burr formation along helix angle in end milling and certificate experimentally mechanics relation of helix angle and burr formation.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.231-234
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• 2002

Ultrasonic machining technology has been developed over recent years for the manufacture of cost-effective and quality-assured precision parts for several industrial application such as optics, semiconductors, aerospace, and automobile. Ultrasonic machining process is an efficient and economical means of precision machining of ceramic materials. The process is non-thermal, non-chemical and non-electric and hardly creates changes to the mechanical properties of the brittle materials machined. This paper describes the characteristics of the micro-hole of $\textrm{Al}_2\textrm{O}_3$ by ultrasonic machining with tungsten carbide tool. The effects of various parameters of ultrasonic machining, including abrasives, machining force and pressure, on the material removal rate, hole quality, and tool wear presented and discussed. The ultrasonic Machining of micro-holes in ceramics has been under taken and the machining mechanism in the ultrasonic machining of ceramics based on the fracture-mechanics concept has been analyzed.

• 한국컴퓨터정보학회논문지
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• 제21권8호
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• pp.65-75
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• 2016

In this paper, we present a novel approach to help MSR researchers obtain necessary data with a tool, termed General Purpose Extractor for Source code (GPES). GPES has a single function extracts high-quality data, e.g., the version history, abstract syntax tree (AST), changed code diff, and software quality metrics. Moreover, features such as an AST of other languages or new software metrics can be extended easily given that GPES has a flexible data model and a component-based design. We conducted several case studies to evaluate the usefulness and effectiveness of our tool. Case studies show that researchers can reduce the overall cost of data analysis by transforming the data into the required formats.

• 산업경영시스템학회지
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• 제21권45호
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• pp.265-277
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• 1998

The control chart has been used widely and importantly as a tool for statistical process control(SPC). Most companies are concerned with improving the quality and the productivity as well as reducing the cost, especially in today's highly competitive environment. Though SPC is known as a technique for consistent quality, it is not used properly due to lack of knowledge about it. It is required to develop a support system for control chart selection and interpretation that can be utilized by non-specialist without hard training or experiences. The support system was developed by applying the expert system tool to popular control charts. Though some researches on this area has been performed, the implemented results expose many problems in field applications due to the unsatisfactory explanation of the selected control chart and limited knowledge base for resolving the problems. This thesis presented an expert system for control chart as solution for these problems. The expert system for the control chart selection and interpretation is developed by using Turbo C and EXSYS which is an expert system development tool.

• 한국기계가공학회지
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• 제20권12호
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• pp.100-106
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• 2021

This paper presents a study on the improvement of the machining quality of sculptured-surfaces of molds according to the shape and posture of the tool. In the existing 3-axis machining, the methods using the ball end-mill and radius end-mill were analyzed for various cutting patterns and compared with those of the 5-axis machining. It was observed that the 5-axis machining using a ball end-mill obtained the finest surface roughness, and for the 3-axis machining, the optimal results were obtained for the one-way machining using a radius end-mill.

• 한국기계가공학회지
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• 제3권1호
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• pp.7-14
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• 2004

Machining error is defined the normal distance between designed surface and actual tool path with tool deflection. This is inevitably caused by the tool deflection, tool wear, thermal effect and machine tool errors and so on. Among these factors, tool deflection is usually known as the most significant factor of machining error. Tool deflection problem is analyzed using Instantaneous horizontal cutting forces. The high quality and precision of machining products are required in finishing. In order to achieve these purposes, it is necessary work that decrease the machining error. This paper presents a study on the machining error caused by the tool deflection in ball end milling of 2 dimensional surface. Tool deflection model and simple machining error prediction model are described. This model is checked the validity with machining experiments of 2 dimensional surface. These results may be used to decrease machining error and tool path decision.

• 한국생산제조학회지
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• 제21권1호
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• pp.33-39
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• 2012

The tool wear and failure in automatic production system directly influences the quality and productivity of a product, thus it is essential to monitor the tool state in real time. For such purpose, an ART2-based remote monitoring system has been developed to predict the appropriate tool change time in accordance with the tool wear, and this study aims to experimently find the relationship between the tool wear and the monitoring signals in cutting processes. Also, the roughness of workpiece according to the wool wear is examined. Here, the tool wear is indirectly monitored by signals from a vibration senor attached to a machining center. and the wear dimension is measured by a microscope at the start, midways and the end of a cutting process. A series of experiments are carried out with various feedrates and spindle speeds, and the results show that the sensor signal properly represents the degree of wear of a tool being used, and the roughnesses measured has direct relation with the tool wear dimension. Thus, it is concluded that the monitoring signals from the vibration sensor can be used as a useful measure for the tool wear monitoring.

• 한국지하수토양환경학회지:지하수토양환경
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• 제21권6호
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• pp.67-79
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• 2016

Gaussian process regression (GPR) is proposed as a tool of long-term groundwater quality predictions. The major advantage of GPR is that both prediction and the prediction related uncertainty are provided simultaneously. To demonstrate the applicability of the proposed tool, GPR and a conventional non-parametric trend analysis tool are comparatively applied to synthetic examples. From the application, it has been found that GPR shows better performance compared to the conventional method, especially when the groundwater quality data shows typical non-linear trend. The GPR model is further employed to the long-term groundwater quality predictions based on the data from two domestically operated groundwater monitoring stations. From the applications, it has been shown that the model can make reasonable predictions for the majority of the linear trend cases with a few exceptions of severely non-Gaussian data. Furthermore, for the data shows non-linear trend, GPR with mean of second order equation is successfully applied.

• 임상간호연구
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• 제19권1호
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• pp.1-19
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• 2013

Purpose: This study was conducted to develop standards to ensure nursing process-based care of oxygen therapy and airway suctioning and to develop a performance measurement tool to evaluate the care applied according to the standards, and finally to determine validity of the standards and the tool. Methods: The standards and the tool were reviewed by a panel of experts and refined based on the panel's suggestions. Validity of the standards and the tool were examined through surveying a total of 366 hospital nurses. Results: The mean validity scores of the performance measurement standards and the tool were 3.58 and 3.55, respectively, out of 4.00. So the performance measurement standards and the tool in this study were found to be acceptable in evaluating quality of nursing care provided at patient admission and discharge. Conclusion: This result indicates that the performance measurement standards and the tool developed in this study are valid instruments to monitor and improve quality of nursing care for oxygen therapy and airway suctioning.