• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.4
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• pp.75-84
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• 2000

The main goal of our research is to compensate the milled surface errors induced by the tool deflection effects, which occur during the milling process. First, we predict cutting forces and tool deflection amount. Based on predicted deflection effects, we model milled surface shapes. We present a compensation methodology , which can generate a new tool trajectory, which is determined so as to compensate the milled surface errors. By considering manufacturing tolerance, tool path compensation is generalized. To validate the approaches proposed in this paper, we treat an illustrative example of profile milling process by using flat end mill. Simulation and experimental results are shown.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.04b
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• pp.408-413
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• 1995

Nowadays, manufacturing system is trending toward integrated circumstance by helping of CAD/CAM/CAT. To use this system effectively, it is necessary to get exact 3 dimensional surface data of an object. We have been using contact method to measure 3 dimensional object profile. But his method has demerit of leaving scrach or small distortion on the object. To improve this, a non-contact measuring method using optical system is adopted. In this paper, We propose optical ring method. Withthis system, We could measure displacement of the object in the range of 45mm having 150mm having 150 .mu. m resolution with no scratch or distortion.

• Journal of Society of Preventive Korean Medicine
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• v.15 no.3
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• pp.67-81
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• 2011

Background : Complementary and alternative medicine has bee used to cardiovascular diseases. In recent years, many hospitals have tried to integrate complementary and alternative medicine(CAM) with conventional medical approaches for patients with chronic diseases. Recently, the prevalence of the use of traditional Korean medicine(TKM) among patients with chronic diseases, expecially, hemiplegia patients after cerebrovascular accident is increasing in Korea. To date, however, there were only few studies addressing the patients' attitudes, and utilization of TKM, compared to the well-documented escalating use of TKM among consumers in Korea. Objectives : The objective of this study was to analyze the prevalence of TKM use among hemiplegia patients after cerebrovascular accident and to determine what factors affect to use CAM among the patients. The study also aims to provide information on TKM and assist therapy selection among various CAM therapies for hemiplegia patients after cerebrovascular accident within health care system in which both practitioners of TKM and practitioners of modern Western medicine coexisted. Methods : The design of the study was descriptive cross-sectional, and data were collected using a 32-items questionnaire. The subjects were one hundred fifty nine patients with chronic diseases who visited or admitted to health care facilities in a hospital in Seoul Metropolitan city, Korea. Data were analyzed using 'SPSS Statistics 18.0 Network Version(on release 18.0.1 of PASW Statistics)' program. Various statistical methods were used to obtain a profile for participants and the therapies most frequently used by hemiplegia patients of TKM. Logistic regression analysis was employed in order to determine the predicting variables of TKM use. Results : The prevalence of the use of TKM was 51.6%. The most common TKM therapies used by the patients included acupuncture(93.2%), herbal medicine(64.8%), and cupping(37.5%). Results of logistic regression analysis revealed that the variables significantly related with TKM use were gender, marital status, job, No. of visiting health care facilities/week. Conclusions : This study shows that the use of TKM among the hemiplegia patients is relatively high in Korea, this topic should be taken into account in the development of a holistic approach for patients with chronic diseases and an efficient chronic disease management system in Korea.

• The Journal of the Society of Korean Medicine Diagnostics
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• v.20 no.2
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• pp.67-75
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• 2016

Objectives There was a correlation between respiratory index and Profile of Mood States (POMS). However, no study has examined the relationship between hyperventilation and POMS. Therefore, this study showed differences in POMS subscales and respiratory patterns between hyperventilation group and normal group. Methods 20 healthy men and women were to complete Nijmegen and Korean-Profile of Mood States(K-POMS) questionnaire aimed at subjects (13 men, 12 women). By attaching a capnometer to the nasal cavity portion, end-tidal $PCO_2$ was measured. Also, marker was attached at Zhangmen, Juque, Shuifen. The movement of the marker was taken as a web cam. Statistical analysis Mann Whitney U test was used for the nonparametric methods. Results In the subscale of K-POMS were significant differences(Tension-0.001, Anger-0.007, Fatigue-0.002, Depression -0.004) between the normal group and the group with the hyperventilation. In addition, between the two groups were obtained a significant result(0.046) in the movement of the Shuifen acupoint. Conclusions Nijmegen questionnaire score is higher, the higher negative subscale scores of K-POMS. Also, differences in Nijmegen questionnaire score may help to determine the presence or absence of the abdominal breathing.

• Geomechanics and Engineering
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• v.8 no.2
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• pp.187-220
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• 2015

Soil disturbance induced by installation of mandrel driven vertical drains decreases the in situ horizontal hydraulic conductivity of the soil in the vicinity of the drains, decelerating the consolidation rate. According to available literature, several different profiles for the hydraulic conductivity variation with the radial distance from the vertical drain, influencing the excess pore water pressure dissipation rate, have been identified. In addition, it is well known that the visco-plastic properties of the soil also influence the excess pore water pressure dissipation rate and consequently the settlement rate. In this study, a numerical solution adopting an elastic visco-plastic model with nonlinear creep function incorporated in the consolidation equations has been developed to investigate the effects of disturbed zone properties on the time dependent behaviour of soft soil deposits improved with vertical drains and preloading. The employed elastic visco-plastic model is based on the framework of the modified Cam-Clay model capturing soil creep during excess pore water pressure dissipation. Besides, nonlinear variations of creep coefficient with stress and time and permeability variations during the consolidation process are considered. The predicted results have been compared with V$\ddot{a}$sby test fill measurements. According to the results, different variations of the hydraulic conductivity profile in the disturbed zone result in varying excess pore water pressure dissipation rate and consequently varying the effective vertical stresses in the soil profile. Thus, the creep coefficient and the creep strain limit are notably influenced resulting in significant changes in the predicted settlement rate.

• Transactions of Materials Processing
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• v.7 no.3
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• pp.246-259
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• 1998

This paper describes a research work of developing a computer-aided design and manufacturing of irregular shaped sheet metal product for blanking or piercing and bending operations. An approach to the system is based on the knowledge-based rules. Knowledge for the system is formulated from plasticity theories experimental results and the empirical knowledge of field experts, This system has been written in AutoLISp on the AutoCAD and in customer tool kit on the SmartCAM with a personal computer and is composed of nine modules which are input and shape treatment, flat pattern-layout, pro-processor module. Based on the knowledge-based rules, the system is designed by considering several factors, such as material and thickness of product complexities of blank geometry and punch profile sheet metal to give flat pattern and automatically account for the adjustment of bending allowances to match tooling requirements by checking dimensions and generating NC data automatically according to drawings of die-layout module. Results carried out in each module will provide efficiencies to the designer and the manufacturer of blanking or piercing and bending die in this field.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.4 s.175
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• pp.811-823
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• 2000

In design and manufacturing airframe structures which are composed of a lot of sub-assemblies and large complex profile shapes it is difficult to reduce so called hardware variations. Accordingly cost increasing factors for manufacturing airframe parts are much more than other machine parts because of the variability of fabricated details and assemlies. To improve cost and quality, accurate assembly methods and DPD techniques are proposed in this paper which are based upon using CAD/CAM techniques, the concept of KC's and the coordinated datum and index throughout the design, tooling, manufacturing and inspection. The proposed methods are applied to produce fuselage frame assemblies and related engineering aspects are described regarding the design of parts and tools in the context of concurrent digital definition. First articles and consequent mass production of frame assemblies shows a great improvement of the process capability ratio from 0.7 by the past processes to 1.0 by the proposed methods in addition to the cost reduction due to the less number of tools, reduced total assembly times and the space compaction needed by massive inventory. The need to achieve better Cpk, however, and future studies to be investigated will be addressed briefly.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.7 no.4
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• pp.96-103
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• 1998

With the advance of processing technology , so as to spare fuel, piston heads used in automobile reciprocating engine have complex 3-dimension, with respect to shape such as ovality, profile, eccentricity, offset, recess. Therefore, coming out of the existing process work used master cam. the process work is performed using a CNC lathe. For a precision processing, the processing work is need to make study of high speed feed gear synchronized with the rotative speed of main spindle. And then the high speed feeding system must maintain high dynamic stiffness, high speed and high positioning accuracy . In this paper, in order to achieve high speed cutting tool feeding. The linear brushless DC motor is used for satisfying this process work. The ball bush and turicite is used as the guidance of the feed gear system. Also linear encoders, digital servo amplifiers and controller are used for controlling driving motor. This paper presents the design and simulation of the new tool feed system for noncircular machining.

• Journal of ILASS-Korea
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• v.19 no.1
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• pp.25-32
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• 2014

For reduction of $CO_2$ emission emitted from combustion engine, the developed nations have been focused on R&D of hybrid electric vehicle. Further more, many automobile companies are researching on various techniques related to engine used in HEV to enhance fuel economy. One of key techniques is miller cycle that control a valve timing to reduce compression stroke for saving energy and increase expansion stroke for high power. In this study, it was investigated the in-cylinder flow characteristics of miller cycle with variable intake valve timing by using the ANSYS simulation code. For simulation, the key analytic parameter defined as intake valve closing timing and cam profile. As main results, it was shown that LIVC cause a lower pressure inside cylinder and had better control turbulence intensity.

• Korean Journal of Computational Design and Engineering
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• v.8 no.2
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• pp.115-121
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• 2003

A new Layered Manufacturing(LM) system, named PaperMill, is developed applying micro milling technology. A micro endmill(127 11m in diameter) is introduced as the cutter of build material. The selected build material for this system is an adhesive-coated paper roll which provides advantages such as good bonding between layers, machinability, and low material cost. A 3-axis CNC controller and three step-motors are used for the movement of X-Y-Z table of the system. For simplicity of the control of mechanism, the control system for feeding the paper roll is uncoupled from CNC controller. Two code converters are developed for the toolpath generation of the new LM system. The NC converter generates a set of NC codes for PaperMill using commercial CAM software while the SML converter generates an NC code from Quickslice's SML format. The NC codes generated from the converters consist of a series of profile data and trigger code for paper feeding. Two sample gears were fabricated to prove the concept of the system, which shown that the dimensional errors of the fabricated gears is under 3.4 percent.