• Industrial Engineering and Management Systems
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• v.12 no.4
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• pp.368-379
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• 2013

Efficiency in work training is a perennial issue due to high-diversity low-volume production, particularly for manufacturers producing office machines which are manually assembled by workers. To reduce the training cost, parts used in training are usually reused; a trainer disassembles a product assembled by a worker in training. This paper proposes a training method that employs disassembly usually performed by a trainer. This method assigns both assembly and disassembly to a worker in training, in contrast to the conventional method. The effectiveness of the proposed method is experimentally discussed in terms of learning assembly motions and work procedure at each learning stage, namely, "undergoing learning," "immediately after learning," and "seven days after learning." The effectiveness of the training method is confirmed. The method improves the stability of work procedure recollection immediately after training. Furthermore, at seven days after training, it improves retention of the assembly motions and work procedure, and also promotes and maintains memory related to product structure.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.22 no.3
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• pp.540-544
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• 1998

Compliance calibration method is frequently used to determine $G_IC$ from the DCB composite specimen. However, the method requires at least 4 to 5 fracture test (loading-unloading) records. In this study, $G_IC$ of unidirectional graphite/epoxy DCB composites was determined from the elastic work factor approach which uses a single fracture test record. In order to inspect the validity of the elastic work factor approach, $G_IC$ determined from the elastic work factor approach was compared to that of determined from the compliance calibration method. It was shown that $G_IC$ determined from the elastic work factor approach was comparable to that determined from the compliance calibration method. That is, the elastic work factor approach can be used to determine $G_IC$ of unidirectional graphite/epoxy DCB specimen from a single fracture record.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.2
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• pp.339-350
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• 1994

This paper presents a method for automatic generation of line balanced assembly sequences based on disassemblability and proposes a method of evaluating an assembly work time using neural networks. Since a line balancing problem in flexible assembly system requires a sophisticated planning method, reasoning about line balanced assembly sequences is an important field of concern for planning assembly lay-out. For the efficient inference of line balanced assembly sequences, many works have been reported on how to evaluate an assembly work time at each work station. However, most of them have some limitations in that they use cumbersome user query or approximated assembly work time data without considering assembly conditions. To overcome such criticism, this paper proposes a new approach to mathematically verify assembly conditions based on disassemblability. Based upon the results, we present a method of evaluating assembly work time using neural networks. The proposed method provides an effective means of solving the line balancing problem and gives a design guidance of planning assembly lay-out in flexible assembly application. An example study is given to illustrate the concepts and procedure of the proposed scheme.

• Journal of Korean Institute of Industrial Engineers
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• v.33 no.3
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• pp.355-363
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• 2007

This paper presents a method of an automatic work time evaluation based on the verification of a disassemblability and assembly configuration. Even though a work time evaluation is an important field of concern for planning assembly lay-out, there are some limitations using cumbersome user query or approximated work time data without considering assembly condition. To overcome such restriction, this paper presents a method to mathematically verify assembly conditions based on the disassemblability, which is defined by the separability and stability cost. The separability cost represents a facility of the part disassembly operation, and the stability cost which represents a degree of the stability for the base assembly motion. Based upon the results, we propose a new approach of evaluating work time using neural networks. The proposed method provides an effective means of solving the work time evaluation problem and gives a design guidance of planning assembly lay-out in flexible manufacturing application. Example study is given to illustrate the concepts and procedure of the proposed schemes.

• Journal of Welding and Joining
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• v.27 no.6
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• pp.55-61
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• 2009

This study aims for determination of cutting work envelope of an articular robot for H-beam cutting. The robot has its own work envelope. The cutting of piece with groove requires the specific position of the torch which contracts the work envelope. This study suggested the new method to determine the cutting work envelope for this case. The method simplified the problem by use of the combination of inverse kinematics and forward kinematics. The method was used for cutting the H-beam with groove. The cutting work envelope was determined easily. The result was verified by 3D simulation system which implements the articular robot with 6 axes and the H-beam in the virtual shop.

• Journal of the Korean Home Economics Association
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• v.41 no.7
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• pp.157-168
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• 2003

The purposes of this study were to explore the rural women's labor by measuring labor value economically. To achieve the purpose, this study applied four methods : replacement cost method individual function, replacement cost method generalist, opportunity cost method and shadow wage method. The results of this study were as follows: 1) Time used for agricultural work and household work by with women were 5.3 hours and 3.8 hours each. 2) According to the methods used, the amounts of valuing rural women's labor were varied and ranged from 23,000 won to 43,000 won per day. This study might help recognize the degree of rural women's labor contribution to the household income of farm households and improve the socio-economic status of rural women through showing the productivity of the rural women's labor.

• Journal of the Ergonomics Society of Korea
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• v.36 no.5
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• pp.601-607
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• 2017

Objective: A method to assess the risk level of agricultural works considering work posture and working time was suggested, and the method was applied to the major fruit crops. Background: It is not complete to analyze only work postures when assessing risk level of agricultural works. Method: $3{\times}3$ matrix was employed, in which the severity level was taken from the REBA method and exposure level was taken from the working time, using the criteria of caution zone/hazard zone. Results: Among the 5 major fruit crops(apple, pear, grape, peach, persimmon), the highest level of ergonomic risk was found in the apple and pear, while medium level was found in other 3 crops, mainly because the working time was less in the 3 crops. Conclusion: It was found that when assessing the overall ergonomic risk of agricultural works, work posture and working time should be considered at the same time. Application: The suggested method could be applied to other non-cyclic tasks.

• Journal of the Korean Society of Safety
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• v.16 no.3
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• pp.106-110
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• 2001

For the policy makers and managers as well as the workers at work, it is important to identify what affects, to what extent, the safety level and costs of work sites. Within this context, the author analyzes fifteen construction work sites of the Incheon International Airport from 1996 to 1999 and shows that the expenditures for safety personnel and education programs contribute to reducing industrial accident costs. In addition, the author demonstrates that the regression analysis out-performs Heinrich method in estimating the accident costs of those work sites.

• Journal of the Korean Society of Costume
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• v.41
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• pp.185-206
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• 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.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.57 no.3
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• pp.275-278
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• 2008

It has been issued that the necessity of Live line work for 765kV vertical double circuit six bundle conductors transmission line when the characteristics of transmission line, the composition of T/L and near the T/L circumstances etc. Others are considered. The Barehand method of UHV T/L is extremely dangerous work and especially it is directly related with lineman life so it is very dangerous. It should be performed several technology developments for live-line work on the UHV T/L, that should be considered such as the electrical influence on workers near the T/L, development of live-line facilities, guarantee of safety, the technical rules of live-line work, the safe method of live-line work and etc. In order to maintain the 765kV transmission lines safely by barehand work, first of all, we should know the analysis of electrical safety level test in live-line work at 765kV vertical double circuit six bundle conductors on the suspension string tower type.