• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.41 no.3
• /
• pp.199-206
• /
• 2005

As the basic study about improvement of yellow croaker drift gill net fishing implement and development of the fishing system, this study drew problem after synthetically analyzing hauling system of yellow croaker drift gill net used in the coast of Chuja Island and tested several characters and analyzed in hauling process with 5 step net hauler model for improving the problem. The analysis results are as follows. When the angle between axises of drum centers was small, it showed the tendency that hauling time was fast. Hauling time was faster when drum was 5 step rather than 3 step. When drum was 5 step, slippery phenomenon was small and hauling was stable. Tension was larger when drum was 5 step rather than 3 step. When drum was 5 step, the range of change of the maximum and minimum value was small and hauling was stable. When drum was 3 step, there was following formula between hauling time ($Ht_3$) and angle between axises of drum centers ($A_g$) $Ht_3$ : ($7.15Hs^{-0.81}$) $A_g^{-0.81}$, when drum was 5 step there was following formula.$Ht_5$ : ($6.45Hs^{-0.75}$) $A_g0.10$, here, Hs is hauling speed. When drum was 3 step and hauling speed was 28cm/sec, tension was $T=0.08A_8^3-1.60A_g^3-0.49A_g+369.56(r=0.99)$, when drum was 5 step, tension was, $T=-0.01A_g^3+1.96A_g^2-34.05A_g+414.58$ (r-0.99), here, T was tension(g).

• Journal of Appropriate Technology
• /
• v.5 no.2
• /
• pp.70-81
• /
• 2019

The garment industry is one of the most labor-intensive manufacturing industries, with its sewing process relying almost entirely on manual labor. Its costs highly depend on the efficiency of this production line and thus is crucial to determine the production rate in real-time for line balancing. However, current production tracking methods are costly and make it difficult for many Small and Medium-sized Enterprises (SMEs) to implement them. As a result, their reliance on manual counting of finished products is both time consuming and prone to error, leading to high manufacturing costs and inefficiencies. In this paper, a production tracking system that uses the sewing machines' energy consumption data to track and count the total number of sewing tasks completed through Convolutional Neural Network (CNN) classifiers is proposed. This system was tested on two target sewing tasks, with a resulting maximum classification accuracy of 98.6%; all sewing tasks were detected. In the developing countries, the garment sewing industry is a very important industry, but the use of a lot of capital is very limited, such as applying expensive high technology to solve the above problem. Applied with the appropriate technology, this system is expected to be of great help to the garment industry in developing countries.

• Journal of the Korean Society of Costume
• /
• v.41
• /
• 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.

• Journal of Biosystems Engineering
• /
• v.39 no.1
• /
• pp.47-56
• /
• 2014

Purpose: In protected crop production facilities such as greenhouse and plant factory, farmers should be present and/or visit frequently to the production site for maintaining optimum environmental conditions and better production, which is time and labor consuming. Monitoring of environmental condition is highly important for optimum control of the conditions, and the condition is not uniform within the facility. Objectives of the paper were to investigate spatial and vertical variability in ambient environmental variables and to provide useful information for sensing and control of the environments. Methods: Experiments were conducted in a strawberry-growing greenhouse (greenhouse 1) and a cherry tomato-growing greenhouse (greenhouse 2). Selected ambient environmental variables for experiment in greenhouse 1 were air temperature and humidity, and in greenhouse 2, they were air temperature, humidity, PPFD (Photosynthetic Photon Flux Density), and $CO_2$ concentration. Results: Considerable spatial, vertical, and temporal variability of the ambient environments were observed. In greenhouse 1, overall temperature increased from 12:00 to 14:00 and increased after that, while RH increased continuously during the experiments. Differences between the maximum and minimum temperature and RH values were greater when one of the side windows were open than those when both of the windows were closed. The location and height of the maximum and minimum measurements were also different. In greenhouse 2, differences between the maximum and minimum air temperatures at noon and sunset were greater when both windows were open. The maximum PPFD were observed at a 3-m height, close to the lighting source, and $CO_2$ concentration in the crop growing regions. Conclusions: In this study, spatial, vertical, and temporal variability of ambient crop growing conditions in greenhouses was evaluated. And also the variability was affected by operation conditions such as window opening and heating. Results of the study would provide information for optimum monitoring and control of ambient greenhouse environments.

• Safety and Health at Work
• /
• v.15 no.2
• /
• pp.228-235
• /
• 2024

Background: Glove reuse poses risks, as chemicals can persist even after cleaning. Decontamination methods like thermal aeration, recommended by US OSHA, vary in effectiveness. Some studies show promising results, while others emphasize the importance of considering both permeation and tensile strength changes. This research advocates for informed glove reuse, emphasizing optimal thermal aeration temperatures and providing evidence to guide users in maintaining protection efficiency. Methods: The investigation evaluated Neoprene and Nitrile gloves (22 mils). Permeation tests with toluene and acetone adhered to American Society for Testing Materials (ASTM) F739 standards. Decontamination optimization involved aeration at various temperatures. The experiment proceeded with a maximum of 22 re-exposure cycles. Tensile strength and elongation were assessed following ASTM D 412 protocols. Breakthrough time differences were statistically analyzed using t-test and ANOVA. Results: At room temperature, glove residuals decreased, and standardized breakthrough time (SBT)₂ was significantly lower than SBT₁, indicating reduced protection. Higher temperature decontamination accelerated residual removal, with ∆SBT (SBT₂/SBT₁) exceeding 100%, signifying restored protection. Tensile tests showed stable neoprene properties postdecontamination. Results underscore thermal aeration's efficacy for gloves reuse, emphasizing temperature's pivotal role. Findings recommend meticulous management strategies, especially post-breakthrough, to uphold glove-protective performance. Conclusions: Thermal aeration at 100℃ for 1 hour proves effective, restoring protection without compromising glove strength. The study, covering twenty cycles, suggests safe glove reuse with proper decontamination, reducing costs significantly. However, limitations in chemical-glove combinations and exclusive focus on specific gloves caution against broad generalization. The absence of regulatory directives on glove reuse highlight the importance of informed selection and rigorous decontamination validation for workplace safety practices.

• The Korean Journal of Air & Space Law and Policy
• /
• v.20 no.2
• /
• pp.235-251
• /
• 2005

German working hour law of 1994(Arbeitszeitgesetz) provides maximum working hour as 8 hours a day and 48 hours per week. The law provides that minimum 11 hours rest-time is required between the end of a day's work and the beginning of the next day's work. Namely, the hour that the workers are put under commanding of the user is restricted within 13 hours per day. In the meantime, article 5, 7, 14, and 15 of the law have some letting the exceptional provisions regarding the working hour and rest-time of flight crew, and 2nd administrative order for the aviation transportation business owner, which is established based on such exceptional provisions(2.DV LuftBO), provides the working hour and rest-time of flight crew quite in detail. The administrative order is detailed quite regarding block time, flight working hour, and rest-time. So, it does not need to interpret additionally. Airlines in Korea should observe the both Labor Standard Act applying to general workers and Aviation Act focused on flight crew, so it is difficult that airlines manages working hour and rest-time of the flight crew efficiently. Therefore, it is desirable that our country refers to and considers adopting this legislation method of Germany which regulates working hour and rest-time of flight crew in detail in the 2.DV LuftBO.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.48 no.2
• /
• pp.209-220
• /
• 2021

The noise is defined as unwanted sound that causes discomfort and physical changes. This study was conducted to evaluate intensity of noise in the pediatric dental clinic and to investigate noise environment of a pediatric dentist. Human ear shaped microphone and mobile noise level meter were used for recording noise and calculating intensity of noise. By recording according to the method specified by Korea Occupational Safety and Health Agency (KOSHA) of Korea Ministry of labor and employment, the following results were obtained. For 16 experimental days, 8 hour time weighted average (8hr-TWA) was 49.33 dBA (A-weighted deci-Bell) on daily average with maximum 58.54 dBA and minimum 33.97 dBA. And Dose was 0.49% on daily average with maximum 1.28%, minimum 0.04%. These values are less than criteria of KOSHA standard (85 dBA, 100%). Comparing the highest noise level for each patient, pulp therapy group and Frankel grade I group were the highest. The intensity of dental noise of pediatric dental clinic didn't meet standard of KOSHA. It is necessary to re-evaluate noise environment by establishing new standards considering environment of pediatric dental clinic.

• Computers and Concrete
• /
• v.3 no.1
• /
• pp.1-15
• /
• 2006

The seismic safety of reinforced concrete containment building can be evaluated by probabilistic analysis considering randomness of earthquake, which is more rational than deterministic analysis. In the safety assessment of earthquake-resistant structures by the deterministic theory, it is not easy to consider the effects of random variables but the reliability theory and random vibration theory are useful to assess the seismic safety with considering random effects. The reliability assessment of reinforced concrete containment building subjected to earthquake load includes the structural analysis considering random variables such as load, resistance and analysis method, the definition of limit states and the reliability analysis. The reliability analysis procedure requires much time and labor and also needs to get the high confidence in results. In this study, random vibration analysis of containment building is performed with random variables as earthquake load, concrete compressive strength, modal damping ratio. The seismic responses of critical elements of structure are approximated at the most probable failure point by the response surface method. The response surface method helps to figure out the quantitative characteristics of structural response variability. And the limit state is defined as the failure surface of concrete under multi-axial stress, finally the limit state probability of failure can be obtained simply by first-order second moment method. The reliability analysis for the multiaxial strength limit state and the uniaxial strength limit state is performed and the results are compared with each other. This study concludes that the multiaxial failure criterion is a likely limit state to predict concrete failure strength under combined state of stresses and the reliability analysis results are compatible with the fact that the maximum compressive strength of concrete under biaxial compression state increases.

• Journal of Drive and Control
• /
• v.20 no.4
• /
• pp.27-34
• /
• 2023

Weeding in orchards is closely associated with productivity and quality. The customary weeding process is both labor-intensive and time-consuming. To solve the problems, there is need for automation of agricultural robots and machines in the agricultural field. On the other hand, orchards have complicated working areas due to narrow spaces between trees and amorphous terrain. Therefore, it is necessary to develop customized robot technology for unmanned weeding work within the department. This study developed a path generation and path control method for unmanned weeding according to the orchard environment. For this, the width of the weeding span, the number of operations, and the width of the weeding robot were used as input parameters for the orchard environment parameters. To generate a weeding path, a weeding robot was operated remotely to obtain GNSS-based location data along the superheated center line, and a driving performance test was performed based on the generated path. From the results of orchard field tests, the RMSE in weeding period sections was measured at 0.029 m, with a maximum error of 0.15 m. In the steering period within row and steering to the next row sections, the RMSE was 0.124 m, and 0.047 m, respectively.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.37 no.4
• /
• pp.347-354
• /
• 1992

Late harvest in peanut has often resulted in reduced yield and dissipation of labor by virtue of increasing over-matured pods causing the pod shattering. Present study was conducted to obtain a basic information for deciding optimum harvest time of the peanut in Chungbuk province by examination of yield components at different harvest time of leading cultivars Saedl and Youngho cultivated with vinyl mulching or non-mulching conditions. Peg number and pod number were significantly increased by vinyl mulching and also significantly different by the harvest time. Pod number increased with the lapse of days after flowering was gradually decreased from 100 days after flowering in saedl and 110 days in Youngho. Number of seed-bearing pods and matured seed percent were significantly increased by vinyl mulching and had tendency to increase with the lapse of days after flowering. There was no significant difference in number of over-matured pods and pod shattering percent between vinyl mulching and non-mulching. They increased drastically in 110 days after flowering in Saedl, but in 120 days after flowering in Youngho, Increase in 100 seed weight by vinyl mulching was statistically nonsignificant in both varieties, however, total seed yield was significantly increased by vinyl mulching, showing maximum yield in 100 days after flowering in the variety Saedl and 110 days in Youngho, respectively, Seed yield was negatively correlated to peg number and positively correlated to pod number, seed-bearing pod number, pod shattering percent, matured seed percent and 100 seed weight, respectively.