• 한국자동차공학회논문집
• /
• 제12권3호
• /
• pp.122-129
• /
• 2004

In plastic working, as working becomes speedy, automatic and working condition deteriorates, the increase of forging working has been remarkable. Therefore, we need the estimation of mold lift in detail, in order to counterplan of effective mold life extension. In this study, on the SKH51, mold steel which is forged by cold working and the KCW1, tool steel of low alloy, we estimated mold life on the base of FEM analysis and investigated mold lift by low cycle fatigue test. Also, this paper suggested a new method of estimation of mold lift.

• Journal of Biosystems Engineering
• /
• 제20권3호
• /
• pp.205-216
• /
• 1995

A fast and inexpensive approximate analysis method to predict power output characteristics of the Stilting engines in a preliminary design stage was investigated. In basic equations proposed by Walker, typical temperatures of working fluids in expansion and compression spaces were treated as those of working fluids in heater and cooler respectively. While the temperature of working fluid in the expansion space was actually lower than that of working fluid in the heater, the temperature of working fluid in the compression space was higher than that of working fluids in the cooler. In this paper, the working fluid temperature of expansion space was treated as lower than the heater temperature and that of compression space was treated as higher than the cooler temperature. Also, according to them, the power output characteristics of the Stirling engine were evaluated with respect to the GPU-3 and 4-215 Stilting engines. The following conclusions were drawn from the analysis. 1. Using the available experimental data from the GPU-3 Stirling engine, it was shown that the approximate analysis predicts the brake power with a maximum error of 19 percent at 1, 000rpm and with a minimum error of 3 percent at 2, 000rpm. 2. The approximate analysis data which for the GPU-3 Stirling engine were much closer to the experimental data than those of adiabatic 2nd order and 3rd order analysis within 1, 500rpm to 2, 500rpm. 3. The approximate analysis data which for the GPU-3 and 4-215 Stilting engines were much closer to the experimental data than those of the Beal number analysis.

• 대한안전경영과학회지
• /
• 제11권2호
• /
• pp.51-57
• /
• 2009

The goal of this study is to propose the effective method of investigating the injurious factors and make improvement plans that prevents the workers against musculoskeletal disorders at plastic product companies and the same business field with similar working conditions and process. A questionnaire are adopted to analyze the symptoms of workers' musculoskeletal disorders, and ergonomic assessment methods such as RULA, OWAS are performed to find out harmful factors of workplace and working posture. Based on the result of the evaluation, to enhance the working environment, improvement of worktable, working space, tools, and outfit was suggested, and induction of mechanical system was also suggested. It can be concluded that the method and process described in this paper could be helpful for diagnosing the musculoskeletal disorders risk factors and making improvement plans to the plastic product companies and the same business field with similar working conditions and process.

• 한국산업보건학회지
• /
• 제31권3호
• /
• pp.274-285
• /
• 2021

Objectives: The question of whether the level of fees paid to working environment measurement agencies is appropriate has long been a matter of concern to the government. In addition, measurement institutions express dissatisfaction with their level of compensation, which has a great influence on the evaluation of a subject's policy. This study is intended to find a way to appropriately calculate working environment measurement fees. Methods: We looked at the principle of fee determination as a basic theory of fee calculation used in fee calculation, the legal and academic aspects of the general method of fee calculation, and government cost calculation standards. Furthermore, we reviewed the research methods applied so far to derive a method of calculating fees appropriate for this environment. Results: The working environment measurement environment is different from other commission calculation environments. The other environment is to appropriately calculate the service price provided by a monopoly public enterprise, while the situation is to appropriately calculate the fees provided by competitive private enterprises. Therefore, the service delivery environment and the delivery entity are different. In this case, the appropriate method of calculating service fees would be competitive pricing. There have also been many problems under the method of calculation by service cost. Conclusions: First, the working environment measurement fee requires an accounting correction of endogenous variables. Second, the theory of calculating fees appropriate for this situation is appropriate for competitive pricing that applies to private competitors. Third, the government should make efforts to make the service supply market a fully competitive market while ensuring that the service fee level is determined at the marginal cost level. Fourth, economically, research on marginal cost levels is needed.

• 복식
• /
• 제41권
• /
• pp.185-206
• /
• 1998

The purpose of this study was to improve productivity for maximum effects with the present equipments and staff. This study compared and analyzed the mea-sured time by using stop watch method and MTM, which was the new measuring method. The flow and results of this study were as follows: 1. This study investigated the theoretical background the efficiency for production management, and the way of productivity improvement through documentary research. 2. Setting up the standard flow on the experi-mental company production, making out a process chart and measuring the actual working hour. 3. The study measured the allowance time applying work sampling. 4. Each process of the movement analysis was filmed by video to use basic data. 5. MTM analysis was taken by choosing 10 processes from front bodice according to the basic movement of MTM. Through the results, this study exclude unneccesary movements and suggest a method for working ways. 6. Using the actual working hour measured by a stop watch calculated the pitch time and presumed the amount of daily productivity. 7. The result of the work sampling came out as 38% of allowance rate. It was 13% higher than the standard amount of woman's jacket allowance rate, which was 25%. The most influencing factor was work discussion. That was because there were commuication problem of the work way between the operator and leader. More adequate use of flow table and level passing table was needed. There were the problems that inappropriate places and sizes made the distance of movements longer and often needed more adjustment of works and surroundings. To prevent breakdowns equipments check ups were necessary before works. 8. The results of MTM analysis were as follow : the time was reduced 40% than the actual measured time by a stop watch. This was because the leveling of the operator was included in the real calculation. Also, leveling was included in MTM analysis and all the conditions were standarized. Therefore MTM method was a scientidic measuring way of establishing the standard time. The presented method of this study, suggested an ideal method eliminating unneccesary motions, and presented standardization of works. Improvement of working methods, work condition and simplifying motions in each 10 processes reduced the working time from total 656 seconds to 301 seconds. 9. The way and time of working was linked together in the MTM analysis methods. Thus data from MTM help suggest not only establishing standard time but also establishing stan-dard work. Plus it includes various ability for improvements of working ways. So it is an objective method which can be widely used in other work studies. 10. The function of a time study is to determine the amount of work produced with a given method. The work rate is used to establish the cost of labor. The wage of worker must be calculated per unit time which is deter-mined before the time study is made. This study tried to introduce the incentive rule for deciding wages according to the standard time by MTM method.

• 생명과학회지
• /
• 제26권2호
• /
• pp.234-240
• /
• 2016

Y-미로는 행동연구 분야에서 작업기억을 측정하는데 흔히 사용된다. 이를 위해 자발적 교대 행동을 측정하고 자발적 교대 비율이 증가하면 작업기억 능력이 향상된 것으로 간주된다. 그러나, 설치류에서 자발적 교대 비율이 작업기억 능력을 정확히 반영하기 어려운 경우가 때때로 존재한다. 이러한 단점을 보완하기 위해 Y-미로에서 작업기억능력을 측정하는 새로운 통계 방법을 개발하였다. 이를 위해 먼저 Y-미로에서 자발적 교대가 이루어질 수 있는 경우를 모두 지정하고 각 경우마다 P_i 값을 구한다. P_i 값은 각 자발적 교대가 이루어지는 경우에서 실제 실험동물이 보이는 확률을 의미한다. 각 동물에서 P_i 값을 모두 더하면 그 값은 한 동물에서 얻은 엔트로피에 해당하고 각 군에서 엔트로피를 통계적으로 분석한다. 이러한 새로운 통계 분석 방법을 평가하기 위해 작업기억능력을 향상시키는 것으로 알려진 풍족한 환경에 노출된 군과 정상군을 10주간 사육한 후 Y-미로에서 작업기억능력을 평가하였다. 그 결과 새로운 통계 분석 방법은 자발적 교대 비율을 이용한 통계의 유의성을 재연하였다. 뿐만 아니라 새로운 방법은 자발적 교대 비율을 이용한 분석법보다 유의성 있는 차이를 얻기가 더욱 힘들었다. 이러한 결과는 높은 엔트로피를 얻기 위해서는 모든 통로와 방향에서 자발적 교대가 이루어져야 함을 의미한다. 종합하면, 새로 제시된 분석법은 자발적 교대 비율을 비교하는 분석방법의 단점을 보완할 수 있으며 설치류에서 작업기억 능력을 평가하는 유용한 통계 방법임을 알 수 있다.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 1996년도 춘계학술대회논문집
• /
• pp.23-30
• /
• 1996

The purpose of this study was to investigate changes in thewall thickness of tube sinking and working forces by the upper bound method and ABAQUS code. The independent variables were : Workpiece material, original wall thickness of tube, die angle, friction, and diameter reduction. The results indicated that of these five variables were a factor in wall-thickness increase and working forces. Three variables, a inner tube wall angle and two angles of the velocity discontinuous surfaces, are optimized in this proposed velocity field by the upper bound method. In this method, we can estimate the working forces and final tube thicknesses whcih are similar to acturla forming process. Optimized process variables which are obtained by upper bound method are used in ABAQUS pre-model . In ABAQUS analysis, the stress and the strain contours which are considered to be heat generation occured by the friction during forming process are observed.

• 대한인간공학회지
• /
• 제16권1호
• /
• pp.85-96
• /
• 1997

This article reviews the effects of VDT tasks on multiple resources for processing and storage in short-term working memory. MD and PD method were introduced toevaluate the modalities (auditory-visual) in the multiple resources model. The subjects conducted 2 sessions of 50 minites VDT tasks. Before, between and after VDT tasks, MD, PD task performance scores and CFF(critical flicker frequency0 values were measured. The review suggested that the modalities of human information processing in working memory were affected by VDT tasks with different task contents.

• 패션비즈니스
• /
• 제14권6호
• /
• pp.23-38
• /
• 2010

The purpose of this study was to develop and evaluate working clothes for shipbuilding workers who work in one of the poorest work environments among national strategic industries that are playing pivotal roles for the Korean economy. For the study method, requirements collected through interviews and field surveys were incorporated to directly weave the fabrics for working clothes. The colors were then selected and the woven fabrics were dyed with the selected colors. Using these, the designs of working clothes were planned from the construction and design aspects and four winter clothes and four spring and fall clothes were produced. Afterwards, the workers dressed in these clothes and workers and managers evaluated them in terms of appearance, color satisfaction, design satisfaction, and safety mind harmony on a five point scale. This study found that the new working clothes offered better functionality, design, and safety compared to existing working clothes.

• Journal of Astronomy and Space Sciences
• /
• 제30권3호
• /
• pp.187-192
• /
• 2013

Honsangui (celestial globe) which is a water-hammering method astronomical clock is recorded in "Juhaesuyong" which is Volume VI of supplement from "Damheonseo", written by Hong Dae-Yong (1731~1783). We made out the conceptual design of Hong Dae-Yong's Honsangui through the study on its structure and working mechanism. Honsangui consist of three rings and two layers, the structure of rings which correspond to outer layer is similar to his own Tongcheonui (armillary sphere) which is a kind of armillary sphere. Honsang sphere which correspond to inner layer depicts constellations and milky way and two beads hang on it as Sun and Moon respectively for realize the celestial motion. Tongcheonui is operated by the pendulum power but Honsangui is operated by water-hammering method mechanism. This Honsangui's working mechanism is the traditional way of Joseon and it was simplified the working mechanism of Shui y$\ddot{u}$n i hsiang t'ai which is a representative astronomical clock of China. This record of Honsangui is the only historical record about the water-hammering method working mechanism of Joseon Era and it provide the study of water-hammering method mechanism with a vital clue.