• 한국공작기계학회논문집
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• 제12권3호
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• pp.75-81
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• 2003

Pocket machining is metal removal operation commonly used for creating depressions in machined parts. Numerically controlled milling is the primary means for machining complex die surface. These complex surfaces are generated by a milling cutter which removes material as it traces out pre-specified tool paths. To machine, a component on a CNC machine, part programs which define the cutting tool path are needed. This tool path is usually planned from CAD, and converted to a CAM machine input format. In this paper I proposed a new method for generating NC tool paths. This method generates automatically NC tool paths with dynamic elimination of machining errors in 2$\frac{1}{2}$ arbitrary shaped pockets. This paper generates a spiral-like tool path by dynamic computing optimal pocket of the pocket boundary contour based on the type and size of the milling cutter, the geometry of the pocket contour and surface finish tolerance requirements. This part programming system is PC based and simultaneously generates a G-code file.

• 한국CDE학회논문집
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• 제6권4호
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• pp.215-221
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• 2001

In the zigzag milling of a pocket having islands, tool retraction is one of the primary factors that decrease productivity. Therefore, tool path with minimum number of tool retraction has been needed. Most researches about this topic have been concentrated on obtaining the optimum solution formulated through the geometric reasoning off pocket. Recently, several attempts were made to simplify this problem into region partitioning in order to get the numerically expressed minimum solution. In this research, a method reducing the number of tool retractions extended from existing region partitioning is provided. Applying the segment that is normal to the reference direction of zigzag milling, region partitioning is carried out and structural elements of the region are searched via graphs of islands and characteristic points. Through the processes presented, the number of region partitioned is less than that of existing processes.

• 한국정밀공학회지
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• 제16권4호통권97호
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• pp.220-228
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• 1999

The machining accuracy has been improved with the development of NC machine tools and cutting tools. However, it is difficult to obtain a high degree of accuracy when machining deep pocket with long end mill, since machining accuracy is mainly dependant on the stiffness of the cutting tool. To improve surface accuracy in machining deep pocket using end mill, the performance by down cut and up cut is compared theoretically and experimentally. To verify usefulness of up milling, various experiments were carried out. As a result, it is found that up milling produce more accurate surface than down milling in machining deep pocket. For effective application of up milling, various values in helix angle, number of teeth, radial depth of cut and axial depth of cut are applied in experiment.

• 문화기술의 융합
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• 제10권3호
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• pp.667-673
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• 2024

본 연구는 건강보험의 본인부담상한제와 민영실손의료보험의 관계에서 야기되는 쟁점을 진단하고, 제도 개선을 위한 정책 과제를 제안하는 것을 목적으로 한다. 문헌연구를 통해 본인부담상한제 초과 환급금 미지급으로 인한 소비자 피해 실태와 건강보험 보장성 강화에 따른 실손보험의 역할 변화를 분석하였다. 연구 결과, 일방적 약관 해석과 불완전판매 관행이 소비자 권익을 침해하고 있으며, 실손보험의 보장 축소에도 불구하고 보험료 인하로 이어지지 않는 문제점이 확인되었다. 이에 상품 구조 합리화, 위험률 산출 투명화, 소비자 정보 제공 강화 등의 제도 개선과 함께, 건강보험과 민영보험의 합리적 역할분담을 위한 사회적 합의 도출이 시급함을 강조하였다. 본 연구는 의료보장체계의 발전적 재편을 위한 정책적 시사점을 제공한다는 점에서 의의가 있다.

• 대한한의학회지
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• 제25권1호
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• pp.142-151
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• 2004

Objectives : To document the use and out-of-pocket expenditure of complementary and alternative medicine(CAM) in Korean adult population. Methods : Nationwide, random-sampled, and population-weighted telephone survey was conducted. The sample size of respondents was 1,000(age over 18). The respondents were asked about their use, out-of pocket expenditure of CAM in the past 12 months. SAS 8.0 statistic package was used for checking the relevance between each variables by performing $x^2-test$ and variance evaluation. Results : In 2001, 64.0% of people experienced more than one alternative therapy and the beneficiary took therapy average figure of 2.07. Alternative therapies were generally used for health promotion(73.7%) rather than curing the disease(26.3%). The most common therapies included Medication(30.2%), Physical-therapy(21.9%) health implements(20.8%), herb medication(19.2%), diet therapy(14.3%) etc. Average annual out-of-pocket expenditure was ￡<192,186. Use varied according to age, living province, income, and education, while cost expenditure did according to sex, health condition, income, education. Conclusions : The use of CAM in Korea is very large and the expenditure for them is 22.6% of national medical expenditure. It shows great need of political and academic approach.

• 한국기계가공학회지
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• 제1권1호
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• pp.38-47
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• 2002

Machining quality has been improved with the development of cutting tools. However, it is difficult to obtain a high degree of quality in machining a deep pocket with a long end mill, since machining accuracy is mainly dependent on the stiffness of the cutting tool and tool holder. To improve machining quality in machining a deep pocket using an end mill, the performance by cutting condition compare with others. Owing to this problem, it is necessary to select suitable tool and holder in the deep pocket machining. In this study, the hydraulic holder for the high speed machining is introduced and the performance of that is compared with others according to cutting conditions. The cutting parameters involved were; slenderness ratio in the range of 3 to 6 (L/D), radial depth of cut from 0.01 to 0.05 mm. Cutting force and surface roughness, precision of form were observed during the experiment to investigate cutting state.

• 한국생활과학회지
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• 제7권2호
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• pp.35-47
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• 1998

The purpose of this study was to examine the actual condition on consumption of adolescents, focused on their pocket money. Three-hundred students attending in middle and high school in Kyounggi Province were selected, and surveyed using questionnaires. Out of them, 272 students were used in statistical analysis, with frequency, percentage and Chi-test in SPSS/PC+ program. The results were as follows : First, most adolescents got pocket money irregularly from their mothers and average amount per month was more than 10 thousands and less than 50 thousands won. And they weren't satisfied with that amount, especially girl students. Second, most adolescents got extra money when it is a gala day or their records were improved. And most of them did nothing on consideration for their pocket money. Third, most adolescents spent pocket money for hobby or leisure and for snacks. Fourth, most adolescents had never guided how to spend money and had never evaluated their money spending. Fifth, most adolescents tried to spend money thoughtfully and evaluated their friends spent money on impulse. Sixth, most adolescents wanted to buy clothings and friends influenced their spending habit.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1989년도 제10회 학술강연회초록집
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• pp.94-99
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• 1989

This paper analyzes file stiffness, damping coefficient, friction force and flow coefficient of externally pressurized oil journal beating, including the effect of journal rotation according to the Sommerfeld number. This paper assumed that the oil in the whole pocket has constant pressure, and that the oil in the whole bearing region has constant viscosity, temperature and density. Reynolds equation is derived from Nuvier - Stokes equation and continuity equation. And solved bearing pressure by ADI method for whole bearing region and fitted with out flow rate of pocket region. The model for numerical simulation is hydro - static oil journal bearing for high-speed, high-accuracy lathe spindle.

• 한국자동차공학회논문집
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• 제22권4호
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• pp.160-164
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• 2014

Recently, there has been an active study about friction force of moving parts for automotive. This study is development and evaluation of oil pockets for journal bearing and tappet valve for range extended electric vehicle. Specially, oil pockets are effect on friction force depend on pitch, size, depth. In this study, fine oil pocket was formed using by etched texturing on the journal bearing and tappet valve. And oil pocket analyzed by SEM and friction force test was carried out by tensile tester. Finally, in this study, it was suggested by round and plane part which journal besring and tappet valve.

• Computers and Concrete
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• 제20권4호
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• pp.483-490
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• 2017

This paper studies on the behavior of reinforced concrete (RC) pipes used in basic sanitation in the conduction of storm water and sanitary sewer. Pipes with 800 mm and 1200 mm in diameter were analyzed. The 800 mm pipes were built with simple reinforcement and the 1200 mm pipes with double reinforcement. For the two diameters of pipes the presence or absence of the pocket was evaluated, and the denomination of each one is spigot and pocket pipe (SPP) and ogee joint pipe (OJP), respectively. The 3D numerical models reproduce the three-edge-bearing test that provides information about the strength and stiffness of the reinforced concrete pipes. The validation of the computational models was carried out comparing the vertical and horizontal displacements on the springline and crown/invert and it was also evaluated the reinforcement strains and the crack pattern. As a main conclusion, the numerical models represented satisfactorily the behavior of the pipes and can be used in future studies in parametric analysis.