• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.03a
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• pp.16-22
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• 2003

The focal mechanisms of the earthquakes occurred in 2001 and 2002 are analyzed to understand the regional stress and tectonics in and around Korean Peninsula. The forty -three fault plane solutions are derived using the polarities of first arrival P-waves recorded at KIGAM, Bmh and KEPRI stations. The result suggest that thrust motion with significant amount of strike slip component is dominant mode of faulting. The larger population of mechanism is characterized by WNW-ESE striking nodal planes. NE-SW direction is interpreted as dominant compressional axis orientation of stress field. These solutions are similar to those of medium size earthquakes studied previously, which is known as typical regional tectonic stress orientation in and around Korean Peninsula.

• Proceedings of the Korean Nuclear Society Conference
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• 1997.05b
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• pp.341-344
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• 1997

A vitrification process is under development in KEPRI for the treatment of low-and medium-level radioactive waste. Although the project is for developing and building Vitrification Pilot Plant in Korea, one of KEPRI's concerns is the quality control of the vitrified glass. This paper discusses a methodology for the estimation of glass composition by on-line measurement of molten glass properties, which could be applied to the plant for real-time quality control of the glass product. By remotely measuring viscosity and density of the molten glass, the glass characteristics such as composition can be estimated and eventually controlled. For this purpose, using the database of glass composition vs. physical properties in isothermal three-component system of SiO$_2$-Na$_2$O-B$_2$O$_3$, a software TERNARY has been developed which determines the glass composition by using two known physical properties(e.g. density and viscosity).

• International conference on construction engineering and project management
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• 2007.03a
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• pp.684-693
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• 2007

The construction industry is a significant component of many economies and typically contains a high proportion of small and medium enterprises. However, it is generally understood that this industry is fragmented, adversarial, not highly innovative and not quick to respond to change. At the same time, the industry is under pressure to continue to embrace new technologies and methods, and to adapt better to current and emerging global issues such as sustainability. In order to meet these challenges, firms in the industry need to understand the issues involved and manage their practices accordingly. This paper describes exploratory research into the role of innovative and environmentally sustainable design and construction practices in one group of construction firms, viz., smaller residential building firms in Queensland, Australia.

• Proceedings of the Ginseng society Conference
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• 1993.09a
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• pp.143-149
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• 1993

Ginseng root explants and calli induced from selected cell lines were cultured on modified Murashige and Skoog's media supplemented with different concentrations of organic or inorganic compounds and plant growth requlators to clarify the effects of chemical composition and plant growth regulators in the medium on the growth of ginseng calli and the production of ginseng saponin. For optimum growth of calli, the concentrations of 2, 4-D and sucrose were the range of 1 to 3 mg/${\ell}$l and 1 to $3\%,$ respectively. And it was clarified that sucrose, nitrogen, phosphate, calcium, magmesian plant growth regulators and their concentrations influcenced the relative biosynthesis of saponin in tissue cultures of Panax ginseng. The patterns of ginsenosides, pharmacologically useful component, were different among the cell lines and contents of ginsenosides were much higher in selected cell lines than in original cell line.

• International journal of advanced smart convergence
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• v.13 no.3
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• pp.267-272
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• 2024

Bicycles and electric bicycles, which are short-distance vehicles, do not generate exhaust gases that cause environmental pollution. Rather, they are in the spotlight because they have exercise effects that help the health of the human body while operating the bicycle. Power-trains of bicycle have traditionally used chains and sprockets, and they still have the largest market share. In the previous study, a new type of bicycle power-train was proposed. The power transmission medium of the proposed power-train device employs a belt. The core of the proposed new bicycle power-train is the configuration of the pulley. The core component of the proposed power-train pulley is a spline. In this study, the basic shape of the proposed power-train model and the basic role and design principles of the spline used in the configuration of the model were studied. The target splines are linear spline used for the central axis of the power-train pulley and helical spline for shifting. The linear spline is a basic shape, and the helical spline is an equation that can calculate the inclination angle and the shift range.

• Korean Journal of Environmental Agriculture
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• v.37 no.4
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• pp.251-259
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• 2018

BACKGROUND: Various culture media have been used for hydroponic cultures of horticultural plants under the smart greenhouses with natural and artificial light types. Management of the culture medium for the control of medium amounts and/or necessary components absorbed by plants during the cultivation period is performed with ICT (Information and Communication Technology) and/or IoT (Internet of Things) in a smart farm system. This study was conducted to develop the cloud-based data analysis system for effective management of culture medium applying to hydroponic culture and plant growth in smart greenhouses. METHODS AND RESULTS: Conventional inorganic Yamazaki and organic media derived from agricultural byproducts such as a immature fruit, leaf, or stem were used for hydroponic culture media. Component changes of the solutions according to the growth stage were monitored and plant growth was observed. Red and green lettuce seedlings (Lactuca sativa L.) which developed 2~3 true leaves were considered as plant materials. The seedlings were hydroponically grown in the smart greenhouse with fluorescent and light-emitting diodes (LEDs) lights of $150{\mu}mol/m^2/s$ light intensity for 35 days. Growth data of the seedlings were classified and stored to develop the relational database in the virtual machine which was generated from an open stack cloud system on the base of growth parameter. Relation of the plant growth and nutrient absorption pattern of 9 inorganic components inside the media during the cultivation period was investigated. The stored data associated with component changes and growth parameters were visualized on the web through the web framework and Node JS. CONCLUSION: Time-series changes of inorganic components in the culture media were observed. The increases of the unfolded leaves or fresh weight of the seedlings were mainly dependent on the macroelements such as a $NO_3-N$, and affected by the different inorganic and organic media. Though the data analysis system was developed, actual measurement data were offered by using the user smart device, and analysis and comparison of the data were visualized graphically in time series based on the cloud database. Agricultural management in data visualization and/or plant growth can be implemented by the data analysis system under whole agricultural sites regardless of various culture environmental changes.

• Journal of Forest and Environmental Science
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• v.9 no.1
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• pp.57-66
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• 1993

The purpose of this study is to offer detailed topographic information for substantially selecting the yarding machine for mechanized yarding operations, classifying the forest site by cluster analysis and principal component analysis, and investigating simultaneously the variables which give much influence on the classification of forest site in forestry build-up region (21, 477ha) of Chunchon Gun, Kwangweon Do. Ten topographic variables were used for the analysis. The results of study were as follows : 1) Gosung region (2, 252ha) was classified into hilly terrain (57%) and steep terrain (43%) and required the tractor prehauling system for the former one and the medium skyline system for latter one, respectively. 2) 65% of Gajung region (2,306ha) and 67% of Kwangpan region (2, 627ha) were classified into steep terrain fitted for the medium skyline system and the portion of both region showed the hilly terrain for the tractor prehauling system. 3) Jiam region (4, 591ha), consisted only of steep terrain, required the medium skyline system. 4) Gunja region (3, 400ha), Sudong region (3, 984ha) and Sinpo region (2, 340ha) were classified into steep terrain, requiring the medium skyline system, with 85%, 75%, and 75%, respectively.

• KSBB Journal
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• v.5 no.4
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• pp.355-363
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• 1990

Methanol-utilizing bacterium isolated from sewage samples in Seoul showed optimal temperature and pH of $33^{\circ}C$ and 7.1 for growth, respectively. The maximum specific growth rate was $0.42hr^{-1}$. The minimum medium composition was reconstituted depending on the surplus and the deficit of each component in the basal medium at steady state. The optimal composition was given as(g/l); Methanol 40, $(NH_4)_2\;SO_42, \;KH_2PO_4\;1.5, \;K_2HPO_4\;0.2, \;H_3PO_4\;0.79, \;Na_2HPO_4{\cdot}12H_2O\;0.15, \;MgSO_4{\cdot}7H_2O\;1.5, \;FeSO_4{\cdot}7H_2O\;0.034, \;MnSO_4{\cdot}4H_2O\;0.005, \;CuSO_4{\cdot}5H_2O\;0.0027, \;CaCl_2{\cdot}2H_2O\;0.25, \;ZnSO_4{\cdot}7H_2O\;0.007, \;(NH_4)_6\;Mo_7O_{24}{\cdot}4H_2O\;0.00048, \;H_3BO_3\;0.00068, \;CoCl_2\; 0.00024$ Under the continuous culture with optimum medium the maximum cell productivity was 3.8g/1/hr at dilution rate $0.23hr^{-1}$. Maximum cell concentration and its protein content were 19.5g/l and 70% at dilution rate of $0.1hr^{-1}$, respectively.

• Horticultural Science & Technology
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• v.18 no.1
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• pp.33-38
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• 2000

This study was conducted in an effort to meet the need for domestic production of hydroponic media and for medium development using recycled hydroponic rockwool slabs. Two experiments were conducted to evaluate the growth of plug seedlings of petunia 'Romeo' in various mixtures including particles of used rockwool slabs (rockwool particles) and wood chips. In the first experiment, seedlings were grown in plugs filled with mixtures of steam- sterilized rockwool particles and chestnut wood chips, which had been weathered for six months and screened through either 2.8 mm or 5.6 mm sieve, at the mixing ratio of 100:0, 75:25, 50:50, 25:75, or 0:100 (v/v). In the second experiment, seedlings were grown in plugs filled with twenty different mixtures of steam-sterilized particles of used hydroponic rockwool slabs with 4 mm chestnut or pine wood chips, coir, peatmoss, or perlite. In the first experiment seedling growth was not affected by particle size of chestnut wood chips, was superior in the control (commercial plug medium) and in 100% rockwool particles, but was suppressed as mixing ratio of chestnut wood chips increased. In the second experiment, leaf length, and shoot fresh and dry weights were the greatest in rockwool particles+peatmoss+coir treatment, followed by rockwool particles+peatmoss treatment. Leaf length was suppressed as ratio of wood chips increased, especially of chestnut wood chips. Root development was the greatest in rockwool particles+peatmoss+perlite treatment, followed by the control, and rockwool particles+peatmoss+coir treatment. The growth was suppressed as the mixing ratio of rockwool particles, peatmoss, or coir decreased.

• Journal of Conservation Science
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• v.32 no.2
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• pp.223-234
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• 2016

Two-component epoxy resin is widely used in the cultural heritage restoration field. However according to mixing ratio of resin and hardener, curing property, mechanical strength and chemical structure differ which have possibility to effect the stability of cultural heritage. Result of questionnaire survey shows hands-on workers in the conservation field tend to mix the epoxy resin with his or her eye measurement when the using amount is small or mix additional hardener to shorten the pot life of epoxy resin. This research aims to analyze the curing property, mechanical strength and chemical structure of rapid curing type epoxy resin and medium curing type one depending on relative ratio of 0.25~4 of hardener to resin. When the amount of hardener was 0.5~2 times more than the resin, exothermic heat and curing speed were both increased. In case of included hardener to resin was lower than official ratio, mechanical strength (tensile shear strength, tensile strength and compressive strength) became higher along with active cross-linking bonding of the epoxy resin. Medium curing type epoxy relatively had lower exothermic heat and slower reaction during curing process. It was observed to be put to definite point of mechanical strength under lower content of hardener than official ratio. While, hardener ratio more than twice the resin slowed down the curing greatly and lowered the adhesion strength also. In conclusion, under the lower mixing rate of hardener than official ratio would show relatively fast reaction with similar mechanical strength. Over the official ratio on the other hand, material property drops rapidly. Accordingly, mixing ratio of epoxy resin is expected to be influential to the stability of cultural heritage.