• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.2 s.233
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• pp.333-340
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• 2005

Feedrate is one of the factors that have the significant effects on the productivity, qualify and tool life in the cutting mechanism as well as cutting velocity, depth of cut and width of cut. In this study, in order to realize the high-efficient machining, a new feedrate optimization method is proposed based on the concept that the optimum feedrate can be derived from the allowable cutting power since the cutting power can be predicted from the cutting parameters as feedrate, depth of cut, width of cut, chip thickness, engagement angle, rake angle, specific cutting force and so on. Tool paths are extracted from the original NC program via the reverse post-processing process and converted into the infinitesimal tool paths via the interpolation process. And the novel NC program is reconstructed by optimizing the feedrate of infinitesimal tool paths. Especially, the fast feedrate optimization is realized by using the Boolean operation based on the Goldfeather CSG rendering algorithm, and the simulation results reveal the availability of the proposed optimization method dramatically reducing the cutting time and/or the optimization time. As a result, the proposed optimization method will go far toward improving the productivity and qualify.

• Journal of Korean Academy of Nursing
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• v.44 no.3
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• pp.339-349
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• 2014

Purpose: This study was done to develop a measurement for stress experienced by patients with schizophrenia during hospitalization. Methods: The preliminary tool was developed through in-depth interviews and a validity verification test of content. For data collection, 15 inpatients with schizophrenia were selected as participants for in-depth interviews and 195 patients admitted to one of eight psychiatric hospitals in four provinces were recruited as participants to test reliability and validity of the preliminary tool. Results: The questionnaire was developed as a four-point Likert-type scale in a self-report form with 28 items. Factor analysis showed 28 items in six factors. Factors were named 'Unjust human rights infringement', 'Futureless life', 'Alienation from other family members', 'Infringement of basic needs', 'Infringement of personal preference' and 'Inconvenience of shared living'. The six factors explained 63.5% of the total variance. Cronbach's alpha for the total items was .93 and for the factors ranged from .65 to .87. Conclusion: A tool to measure stress in patients hospitalized with schizophrenic was developed based on identified hospitalization stress experiences. Study results indicate that this tool can be used to evaluate hospitalization stress in these patients and will contribute to establishing nursing interventions for relief of hospitalization stress.

• Journal of the Korea Society of Computer and Information
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• v.9 no.3
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• pp.135-141
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• 2004

With the diversified and enlarged softwares, the issue of software maintenance became more complex and difficult and consequently, the cost of software maintenance took up the highest portion in the software life cycle. We design Reverse Engineering Tool for software restructuring environment to object-oriented system. We design Rule - Based Reverse - Engineering using Class Information. We allow the maintainer to use interactive query by using Prolog language. We use similarity formula, which is based on relationship between variables and functions, in class extraction and restructuring method in order to extract most appropriate class. The visibility of the extracted class can be identified automatically. Also, we allow the maintainer to use query by using logical language. So We can help the practical maintenance. Therefore, The purpose of this paper is to suggest reverse engineering tool and evaluation reverse engineering tool.

• The Korean Journal of Health Service Management
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• v.7 no.2
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• pp.101-111
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• 2013

To develop the Korean-Version-Improvement program for ordinary people, we investigate how Korean-High-Intelligent people use their cognitive function, intellectual capacity and Intelligent Quotient test. Using Mensa iq test, we classify intelligent examination tool into various components; visual, geometrical component and cognitive interpretation component. Also we organized each component, got database of intelligent subjects sample, classified itemized availability. Based on these things, we prove efficiency of intelligent examination tool. We found out that high intelligent people showed high Intelligent Index using visual cognitive stimulation with cognitive function when subjects were exposed to certain situation; solving the problem. This intelligent examination tool is low price and safe and easily carrying out with personal computer. If we develop intelligence quotient examination customized with mental retardation populations, a variety of subjects will improve their cognition with efficiency and inexpensively.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.3
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• pp.174-181
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• 2012

The spindle unit is a core part in high precision machine tool. Rotation accuracy of spindle unit is needed for high dignity cutting and improving the performance of machine tool. However, there are many factors to effect to rotational error motion(rotation accuracy). This study studied how rotational error motion is variation when unbalance amount is variation. Rotation accuracy of initial spindle unit is decided depending on parts and assembly such as bearing. When it is rotation, vibration and noise is appeared depending on volume of unbalance amount, so it works to decrease unbalance amount. The purpose of the study tests that unbalance amount how much effects to initial rotation condition. The result of the study shows that accuracy of parts and assembly is highly necessary to reach high rotation accuracy and unbalance amount hardly effects to initial rotation accuracy. However, it shorten spindle's life because vibration and noise is increasing by increasing unbalance amount and we can expect situation that rotation accuracy is falling by long time operation.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.7
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• pp.963-970
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• 2010

This study makes an estimate of the laser-assisted machining (LAM) of an economically viable process for manufacturing precision silicon nitride ceramic parts using a high-power diode laser (HPDL). The surface is locally heated by an intense laser source prior to material removal, and the resulting softening and damage of the workpiece surface simplify the machining of the ceramics. The most important advantage of LAM is its ability to produce much better workpiece surface quality compared to conventional machining. Also important are its larger material removal rates and longer tool life. The cutting force and surface temperature were measured on-line using a pyrometer and a dynamometer, respectively. Tool wear, chips and the surface of the workpiece were measured using optical microscopy, and the surface and fractured cross-section of $Si_3N_4$ were measured by SEM. During the LAM process, the cutting force and tool wear were reduced and oxidation of the machined surface was increased according to the increase in the laser power. Moreover, the more the feed rate increased, the more the cutting force and tool wear increased.

• Journal of Korea Multimedia Society
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• v.18 no.2
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• pp.120-127
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• 2015

Mild Cognitive Impairment(MCI) is a prior step to Alzheimer's Disease(AD). It is different from AD which is seriously affecting daily life. Particularly, the hippocampus could be charged a crucial function for forming memory. MCI has a high risk about progress to AD. Our investigated research for a relationship between hippocampus and AD has been studied. The measurement of hippocampus volumetric is one of the most commonly used method. The three dimensional reconstructed medical images could be passible to interpret and its examination in various aspects but the cost of brain research with the medical equipment is very high. In this study, 3D visualization was performed from a series of brain Magnetic Resonance Images(MRI) and we have designed and implemented a competitive software tool based on the open libraries of Visualization ToolKit(VTK). Consequently, our visualization software tool could be useful to various medical fields and specially prognosis and diagnosis for MCI patients.

• Journal of the Korean Society for Precision Engineering
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• v.34 no.4
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• pp.247-251
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• 2017

Titanium alloy has been widely used in the aerospace industry because of its high strength and good corrosion resistance. During cutting, the low thermal conductivity and high chemical reactivity of titanium generate a high cutting temperature and accelerates tool wear. To improve cutting tool life, cryogenic machining by using a liquid nitrogen (LN2) jet is suggested. In cryogenic jet cooling, evaporation of LN2 in the tank and transfer tube could cause pressure fluctuation and change the cooling rate. In this work, cooling uniformity is investigated in terms of liquid nitrogen jet pressure in cryogenic jet cooling during titanium alloy turning. Fluctuation of jet spraying pressure causes tool temperature to fluctuate. It is possible to suppress the fluctuation of the jet pressure and improve cooling by using a phase separator. Measuring tool temperature shows that consistent LN2 jet pressure improves cryogenic cooling uniformity.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.7 no.3
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• pp.43-50
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• 1998

In the use of CNC machine tool, the unmanned production system has been growing in the manufacturing field. Thus, it is necessary to monitor adequate tool fracture during the cutting process efficiently. This experimental study is intended to investigate the development of flank wear in sysnchronous turning of differential materials(Aℓ/GC) which is used in industrial application and it is acknowledged as a machine to difficult material. In cutting process change of velocity, change of feed, and change of depth of cut were investigated on the effect of flank wear, and slenderness ratio is also investigated. The conclusions of this paper are summarized as follows; 1.Under the high cutting speed condition, the flank wear is affected by the feed and depth of cut. but the influence of feed on the flank wear is larger than the depth of cut and that is reduced when the velocity is low. 2.Under the high cutting speed, as the smaller slenderness ratio is, the shorter tool life is under the lower cutting speed, the effect of slenderness ratio on the flank wear is low. 3.Using the characteristics of cutting force, the flank wear of a tool can be detected 4. Investigating the development of flank wear, there are almost no differences between the characteristics of cutting force and feed force. Finally, these data from the differntial materials cutting process will be used in the basic field of precision and economic cutting process.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.172-175
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• 2002

High speed machining is one of the most effective technologies to improve productivity. It can give great advantage for manufacture of die and Moulds. However, when machining of micro groove in high speed machining a severely thermal damage was generated on workpiece and cutting tool. Generally, the cutting fluid is used to improve penetration. lubrication. and cooling effect. In order to rise the performance of lubrication. it contains extreme pressure agents (Cl, S, P). But the environment of work room go bad by those additive. Therefore, the compressed chilly air with oil mist system was developed to replace the conventional cutting fluid system. This paper carried out the tests to evaluate the machinability by the cutting environment in high speed micro groove machining of NAK80 (HrC40). Compressed chilly air with oil mist was ejected on the contact area between cutting edge and workpiece. The effect of this developed compressed chilly air with oil mist system was evaluated in terms of tool life. The results showed that the tool lift of carbide tool coated TiAlN with compressed chilly air mist cooling was much longer than that of the dry and flood coolant when cutting the material.