• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.5
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• pp.301-308
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• 2005

This study was carried out to investigate the effect of stem-cutting (SC) length and portion on the major agronomic characters related with dry matter production and accumulation, and to examine their relation­ships in cassava. When cassava was planted with longer SCs or with older portion SCs, major canopy or source characters like leaf number and leaf area index developed excessively, while tuber yields could be reduced due to the decrease of root/shoot ratio, relative growth rate, root dry weight, and harvest index, particularly in the bitter varieties (high cyanide-level varieties). It was considered that the sweet varieties (low cyanide-level varieties) be early­bulked with higher tuber yield when they are planted with the 25-30 cm long SCs or with the SCs from young type to semi-mature portions of mother stems, while the bitter varieties with the 15-20 cm long SCs or with the SCs from semi-mature to hardwood portions of mother stems, respectively. However, a significant interaction between length and portion of SC was not observed in all agronomic characters.

• Journal of the Ergonomics Society of Korea
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• v.30 no.4
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• pp.473-480
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• 2011

Objective: This paper presents the results of a literature review undertaken to analyze the types and risk factors of unsafe posture in accordance with the crops and the working position and to introduce various ergonomic intervention approaches. Background: There is clear and consistent evidence that agricultural work has been rated as one of the dangerous occupations in the world. A considerable number of adverse health conditions, including musculoskeletal disorders(MSDs) are related to agricultural work. Method: An agricultural work requires squatting, kneeling, and bending(stooping) postures for significant periods of the work day which due to a wide variety of activities such as planting, cultivating and harvesting various agricultural products. Thus, each of these postures is analyzed in detail to recommend the improvement methods. Results: Various unsafe postures in agricultural works are revealed and analyzed. It is proven that ergonomics intervention has the potential benefits to reduce MSDs among agricultural workers. Two types of ergonomic intervention methods were discussed to improve unsafe working postures, engineering controls and administrative controls. Conclusion & Application: As a concluding remark, this article can be used as a reference manual for the agricultural workers and also used to raise the research community's awareness to the risk of unsafe working postures for workers in agriculture.

• Journal of Korean Society on Water Environment
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• v.21 no.1
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• pp.92-98
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• 2005

Nutrients removal performance of a contact oxidation reactor covered with soil was investigated when basalt rubble was used as a contact medium under various operating conditions. The objective of the experiment was to determine the effectiveness of the system by measuring the removal efficiencies of nutrients from a technical and economical viewpoint. Under the ranges of HRT(20 and 40 hrs) in the experiment, the removal rates of organic matter were as high as 97.5% by showing an effluent $BOD_5$ of less than 10 mg/L. The test of nitrogen removal when the turf was planted on the top soil showed that the average removal rate increased as much as 25% as compared to that without planting. It was suggested that the construction and maintenance cost could be reduced over 20% when the HRT of the system was decreased from 72 to 40 hrs.

• Journal of the Korean Institute of Landscape Architecture
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• v.21 no.1
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• pp.63-82
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• 1993

In the middle areas of South Korea, we collected 308 wild herbaceous species for studying the possibility of landscaping and, growing them at West in Yongin country of Kyunggi province. We observed their vegetative and flowering characteristic. And the result is as follow: 1. 76 species(24.7%) such as Hosta capitata, etc. of them are thought useful for flower-bedding or landscaping for park and ground-covering, while 94 species(30.6%) are regarded useful for ground-covering, potting and indoor-planting. They are Nepatica maxima and Thaliticum minus var. hypoleucum, etc. 46 species(15%) seems to be useful for flower-bedding, ground-covering and potting. 2. 264(85.7%) of all the observed species are for the enjoyment of their flowers, while 36 species(11.4%) for the enjoyment of their leaves, and 9 species(2.9%) for their fruit. They are Viburnum dilatatum, etc. 3. As for the relation of their habits to light conditions, 148 species(48%) grow int he full sun of more than 50,000Lux, 138 species(44.8%) usually in in the half shade of 20,000 to 30,000Lux, 15 species(4.9%) in the shade of some 10,000Lux, and 7 speciese grow either in the full sun or in the shde. 4. some species such as Wasabia koreansa, Allium succuliferum, Asterglehni, Ligulariafisheri, Ligularia stenocephala Epimedium koreanum are considered available as edible plants as well as ornamentals plants, and Houttuynia cordata. Saururus chinensis, Epimedium koreanum need to be further developed not only as ornamental plants but also medicinal plants.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.5 no.1
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• pp.59-65
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• 2002

The community of common reed (Phragmites australis) is expanded by the development of new shoots from nodes of rhizomes and old shoots in natural environments. We developed the useful technique to construct reed mats of floating islands developed from shoot nodes of reeds for the purpose of the rapid stabilization of vegetation and the application of adapted plants with their specific environmental conditions. The vegetation development was compared in the floating islands planted with the different reed samples. The reed samples were consisted of four types : long shoot in the length of 100 cm (AG I), short shoot of 15 cm (AG II), long rhizome of 100 cm (BG I) and short rhizome of 15 cm (BG II). Shooting started earlier in BG I and BG II than in AG I and AG II. But the rate of shooting was higher in AG I and AG II than in BG I and BG II. After four weeks, AG I and AG II were higher than BG I and BG II in the biomass and density of newly developed shoots. These results showed that the construction of sod mats by planting only reed shoots was a useful technique to develop vegetation on the floating islands.

• Journal of the Korean Solar Energy Society
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• v.34 no.6
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• pp.27-37
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• 2014

Heat island is caused by changes of land coverage structure of cities and use of energy in buildings. As a result energy use in buildings get to increase further followed by rising of GHG emission and deteriorating climate change. Eco-friendly housing complex is a kind of plan that applies environmental control elements like water and green spaces to housing complex. With these methods, it can be expected to create thermal environment of indoor and outdoor. In this paper quantitative examination is studied on using CFD to find out the effects of river, water permeable, parks and planting on thermal environment. And by comparing field measurements with CFD results which are aimed to development phase housing complex, feasibility and usability of the CFD analysis results are confirmed. And also, analysis on the ventilation performance followed by natural ventilation system is analyzed by selecting one building in housing complex. Based on the results, the possibilities of energy reduction through making thermal environment and applying natural ventilation are studied. With these outcomes, creating thermal conditions and using natural ventilation would be contributed to GHG reduction.

• Journal of the Korean Institute of Landscape Architecture
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• v.23 no.2
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• pp.148-156
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• 1995

This study was conducted to investigate the actual vegetation and plant community structure of the urban forest in Kwangju Metropolitan City. Thirty eight plots in the urban forest were set up by the clumped sampling method. The degree of green naturality, 6 that is artifical planting area covered 10.9% in Kwangju Metropolitan City and Pinus densiflora community covered 48.7% of the actual vegetations of urban forest. Canopy height, Diameter of breast height (DBH) and No. of species in urban forest were 13.5m, 21cm and 24 species, respectively. The soil conditions and community structure of the urban forest were differenced by location of urban and suburban area. The plant communities divided into six groups which were Quercus acutissima community, Q. acutissima-Robinia pseudo-acacia community, Pinus rigida Community, P. rigida-P. densiflora community, P. densifrora-Q. acutissima community and Q, serrata-P. densiflora community. Successional series of the urban forest in the surveyed area were proceeding from P. dinsiflora to Quercus species. The species diversity of plant were high in natural plant community but low in artificial plant community. Tree density in the canopy layer varied from 600ea/ha to 2,800ea/ha.

• Journal of Forest and Environmental Science
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• v.29 no.1
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• pp.1-14
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• 2013

Acacia mangium is an evergreen fast-growing tropical tree, which can grow up to 30 m tall and 50 cm thick, under favorable conditions. It is a low-elevation species associated with rain forest margins and disturbed, well-drained acid soils. It is native to Papua, Western Irian Jaya and the Maluku islands in Indonesia, Papua New Guinea and north-eastern Queensland in Australia. Due to its rapid growth and tolerance of very poor soils, A. mangium was introduced into some Asian, African and western hemisphere countries where it is used as a plantation tree. A. mangium has good quality wood traits, such as a comparatively low proportion of parenchymatous cells and vessels, white and hard wood, and high calorific value. Therefore, it is useful for a variety of purposes, such as furniture, cabinets, turnery, floors, particleboard, plywood, veneer, fence posts, firewood, and charcoal. It is also being used in pulp and paper making because it has good pulp traits, with high yields of pulp, quality of kraft, and produces paper with good optical, physical and surface properties. Because there are significant provenance differences in growth rate, stem straightness, heartwood formation and frequency of multiple leaders, the productivity and quality also varies depending upon environmental conditions, so genetic improvement programmes have been undertaken in countries like Australia, India, Indonesia, Malaysia, the Philippines, Taiwan and Thailand. The programme includes provenance identifications and testing, plus tree selection and clonal multiplication, establishment of seed orchards and hybridization. The phenology, reproductive biology, fruit characteristics, silvicultural practices for cultivation, pest and diseases problems, production of improved planting stock, harvesting, wood properties and utilization have been discussed in this paper.

• Korean Journal of Remote Sensing
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• v.29 no.6
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• pp.611-619
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• 2013

Although the need of crop production has increased in Mongolia, crop cultivation is very limited because of the harsh climatic and topographic conditions. Crop lands are sparsely distributed with relatively small sizes and, therefore, it is difficult to survey the exact area of crop lands. The study aimed to find an easy and effective way of accurate classification to map crop lands in Mongolia using satellite images. To classify the crop lands over the study area in northern Mongolia, four classifications were carried out by using 1) Thematic Mapper (TM) image August 23, 2) TM image of July 6, 3) combined 12 bands of TM images of July and August, and 4) both TM images of July and August by layered classification. Wheat and potato are the major crop types and they show relatively high variation in crop conditions between July and August. On the other hands, other land cover types (forest, riparian vegetation, grassland, water and bare soil) do not show such difference between July and August. The results of four classifications clearly show that the use of multi-temporal images is essential to accurately classify the crop lands. The layered classification method, in which each class is separated by a subset of TM images, shows the highest classification accuracy (93.7%) of the crop lands. The classification accuracies are lower when we use only a single TM image of either July or August. Because of the different planting practice of potato and the growth condition of wheat, the spectral characteristics of potato and wheat cannot be fully separated from other cover types with TM image of either July or August. Further refinements on the spatial characteristics of existing crop lands may enhance the crop mapping method in Mongolia.

• IE interfaces
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• v.18 no.3
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• pp.288-296
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• 2005

Many jobs and activities in our daily lives require squatting postures. The fore part includes housekeepers, farmers, and welders and the latter includes a wide variety of activities such as housekeeping; planting, cultivating and harvesting various agricultural products; grinding, welding, etc. It is speculated that prolonged squatting postures without any supporting stool would gradually cause musculoskeletal injuries to workers. This study is conducted to examine the proper height of stools according to the position of the working materials and to develop wearable stools for workers with squatting posture. Forty male and female subjects participated in the experiment to find the proper height of stools according to the position of the working materials. Subjects were asked to squat and work with 3 different working positions: floor level; ankle level; shank level of 3 different stool height conditions: 10cm height; 15cm height; and 20cm height. After 5 minutes of maintaining a squatting work posture while sitting on the different height stools, Likert summated rating method as well as pairwise ranking test was applied to evaluate the user preferences for provided stools under the conditions of different working positions. The results of statistical analysis show that the subjects preferred 10cm height stool for floor level, 15cm height stool for ankle level, 20cm height stool for knee level. We thus strongly recommend to use appropriate height stools in accordance with the different working positions. Moreover, a prototype wearable stool was designed such that workers with squatting posture do not need to move the stool while they are moving about. The purpose of developing wearable stool was to decrease the physical stress and hence promote worker's health who work with squatting posture.