• 한국분무공학회지
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• 제4권1호
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• pp.55-61
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• 1999

The first maximum point in the stability curve of liquid jet, i.e., the critical point is associated with the critical Reynolds number. This critical Reynolds number should be predicted by simple means. In this work, the critical Reynolds number in the stability curve of liquid jet are predicted using the empirical correlations and the experimental data reported in the literatures. The critical Reynolds number was found to be a function of the Ohnesorge number, nozzle lengh-to-diameter ratio, ambient Weber number and nozzle inlet type. An empirical correlation for the critical Reynolds number as a function of the Ohnesorge number and nozzle length-to-diameter ratio is newly proposed here. Although an empirical correlation proposed in this work may not be universal because of excluding the effects of ambient pressure and nozzle inlet type, it has reasonably agrees with the measured critical Reynolds number.

• 한국농공학회논문집
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• 제50권1호
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• pp.95-106
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• 2008

Eco-friendly material and implementation methods have become important along with the existing standardized maintenance concept for the irrigation and flood control. However, the intrinsic function of the hydraulic structure is water supply and disaster prevention. Therefore, the material and work methods should be considered both eco-friendliness, durability and safety which are prerequisite elements to maintain the engineering function. In this study eco-friendly material and work methods would be classified into the vegetation based system, eco-friendly concrete system and stone-material system according to the characteristics of material. The quality standard for durability followed KS specification and related regulations. The quality standard for safety and eco-friendliness was set after literature review, and the database was developed using the standard. The structure applicable to onsite - the eco-friendly material and work method were classified based on the function and material of the hydraulic structure. Finally, database has been established for convenient management and selection of the proper material and work method. The eco-friendly material and work method could be searched easily for the convenience of the users, and the web-based data system has been developed for continuous registration of the material and work methods to be developed in the future.

• 농촌지도와개발
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• 제15권4호
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• pp.599-619
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• 2008

The study is to develop indicators for woman famers center using focus group meeting and AHP(Analytic Hierarchy Process), which is a method to derive relative weights for each evaluation indicators. The results of this study are as follows. We determined such as the three indicators that planning establishment(seven), promotion process of work(six), performance of work(nine). We analysed the weights of this indicators by AHP. The relative weights of performance of work was 0.5269, planning establishment 0.2554 and promotion process of work marked 0.2177. It was suggested that further research should be carried out to develop more objective assessment indicators.

• 한국농공학회지
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• 제40권1호
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• pp.106-117
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• 1998

The nature of stress-path dependency, the principle that governs deformations in granular soil, and the use of Lade's double work-hardening model for predicting soil response for a variety of stress-paths have been investigated, and are examined The test results and the analyses presented show that under some conditions granular soils exhibit stress-path dependent behavior. For stress-paths involving unloading or reloading, the stress-path with the higher average stress level produces the larger strains, whereas all stress-paths having the same intial states of stress, and involving only primary loading conditions, produce strains of similar magnitudes. Experimental evidence indicates that the stress- path dependent response obtained from the double work-hardening model is also observed for real soils. It is concluded that the influence of stress history on the friction angle is negligible and the strains increment direction is uniquely determined from the state of stress but is not perpendicular to the yield surface. The strains calculated from Lade's double work-hardening model are in reasonable agreement with those measured.

• 대한가정학회지
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• 제41권7호
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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.

• 농촌지도와개발
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• 제2권1호
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• pp.61-70
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• 1995

The decentralization of local extension authority is due to several aspect of improper law on extension. First, extension authority has not treated the extension law properly though it has many local office in province, counties, villages. Second, the authority concentrated too much on the service ignoring the local offices are under the improper law. Third, the authority lost their dignity when other institutions argue for their work on the extension services, Extension Institution should change, but the change should come with proper law environment.

• 대한인간공학회지
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• 제30권4호
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• pp.437-441
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• 2011

Objective: The objective this paper is to introduce the agricultural ergonomics and to show the importance of it in improving the agricultural works. Background: Despite of rapid advancement of technologies and adoption of modern mechanical equipments at farms in Korea, most of agricultural works have still remained manual and thus have regarded as one of the hardest works. With aging and feminization in rural areas, the need to improve agricultural works has grown quite much. Agricultural ergonomics have been known as a good tool in improving agricultural works around the world. Recently Korean government initiated a national program of providing assistive equipments to help farmers and a few ergonomists started to apply agricultural ergonomics in our rural villages as a part of this program. Method: This study reviewed how Ergonomics was used for the agricultural work. Results: Methods of Ergonomics which are used for the agricultural ergonomics and the simple procedure of the agricultural ergonomics were presented. Conclusion: It was found that agricultural works can be improved quite much using the agricultural ergonomics principle and the musculoskeletal stress of farmers can be reduced significantly.

• 농촌지도와개발
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• 제19권1호
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• pp.1-28
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• 2012

The Extension Program accountability will continue to be an influential force to develop agriculture and rural area. As we incorporate new approaches into our service program and respond to new domains of knowledge, we must also consider how our assessment strategies may need to change in order to meet local and other external standards. The main purpose of the study was to be what the best way of Extension Service is set farmers' educational needs met and to be what kind of methodologies and role of Extension system should provide for their faced problem solving effectively. The major results of the study on Farmers' needs toward Korean Extension Services are summarized as follows. First, it is observed that, when the farmers' perceptions were analyzed, the most ranked by the farmers' needs was "having nice extension workers to get advice and solve their problems on the farm in all at once." Farmers had especially more positive attitudes in the categories of interest and careers in ag-technology. To do services level up, the headquarter of Rural Development of Administration must be work with local branches to effectively deliver their missions and educational objectives to target crops and farmers group. And farmers were strongly needed "a specialized service team will be organized" to work closely with operating services for ag-products processing, packing and marketing. The recommendations were made by: farmers' needs should be identified and announced by computer networking development to solve their problems faster. Also, provincial and county level service members should have a chance to working at research institute or related work places with their incentives, which system will be easer to meet farmers' needs and deal with their problems so that the systematic approaches should be managed and recorded their educational attendings, education contents and even their farming corporations. Finally, Agricultural Extension Service should be met to general ag-technology literacy and be balanced with knowledge of other industries and be competitive service with better values in non-agricultural sectors.

• 한국농공학회논문집
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• 제58권1호
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• pp.53-59
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• 2016

This study was conducted by the slump test and the consistency test of the fiber mixed soil which is soil reinforced with fiber as a reinforced material to investigate and estimate the difficulty degree of work and the proper water content. So I would like to present the fundamental data that establishes the work standard of the fiber mixed soil. In conclusion, in this study the slump value of the fiber mixed soil increases over-all according to the increase of the water content although it has a little difference of the increase range and it is smaller than one of the soil. It is estimated that the aggregating and throwing work of the fiber mixed soil would be fine when it has the about 25 % water content and the wall and floor plastering work is the about 30 % ~ 35 % and the flowing and pouring work is the about 40 % water content as well as the mold compacting work is the about 20 %. There is no decreasing of the workability when the soil is reinforced by the fiber because the workability characteristics of the fiber mixed soil is similar to the one of the soil. Therefore, It is estimated that using the fiber as a reinforced material of soil would be appropriate for the construction.

• 농업과학연구
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• 제42권2호
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• pp.117-124
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• 2015

In forest work, working conditions are very hard to improve. The good posture is believed to bring about direct improvements such as accident prevention. Therefore, this research carried on analysis of working posture in forest work (construct in stepping-stone) using OWAS analysis system. According to the analytical results provided by OWAS, the ratio of category III (Work posture has a distinctly harmful effect on the musculoskeletal system) has shawn that worker 2 was 32.2%, worker 1 was 25.2% and worker 3 was 15.5%. Furthermore, the ratio of category IV (Work posture with an extremely harmful effect on the musculoskeletal system) has shown that worker 2 was 9.8%, worker 3 was 1.4% and worker 1 was 1.2%. According to the OWAS method, percentage of OWAS action categories III and IV in the worker 2 was higher than another workers.