• Journal of Plant Biotechnology
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• v.41 no.3
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• pp.134-139
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• 2014

The aim of this study was to establish the condition of regeneration for white balloon flower (Platycodon grandiflorum DC. cv. Jangback) and to manage for the raising of seedling with in vitro regenerated plants. It was examined that 0.5 mg/L of NAA and 1.0 mg/L of BA was the best composition for the callus and shoot induction (up to 600%). NAA was better than IBA for the induction of root and it took 16.9 days for the induction of rooting on the MS soild media containing 0.5 mg/L of NAA and the final rooting ratio was up to 75%. Out of 5 different bed soils purchased from local market, "Tosil" was identified to be the best for the acclimation and growth of in vitro regenerated balloon flower. In detail, on 8 weeks after planting of in vitro regenerated plants in pots containing "Tosil" bed soils, the plant hight was increased up to 2-fold (12.8 cm), 3.5-fold (27) for the number of leaf and 1.5-fold (4.5 cm) for the leaf length when compared to the other four bed soils, respectively. Our preliminary results indicate that it is possible to prevent the occurrence of blue balloon flower in the massive cultivated area of white balloon flower by providing the seedlings raised from in vitro regenerated plants.

• Journal of the Korea Concrete Institute
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• v.15 no.2
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• pp.163-172
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• 2003

As concrete structures are getting larger, higher, longer, and specialized, it is more required to develop steel fiber concrete and apply to the real world. In this research, it is aimed to have fatigue strength examined, varying the steel fiber content by 0%, 0.75%, 1.00%, 1.25%, by experimental study of Two-spans Beam with Steel Fibrous with repeated loads. The ultimate load and the initial load of flexural cracking were measured by static test. In addition, the load versus strain relation, load versus strain relation, load versus deflection relation, crack pattern and fracture mode by increasing weight was observed. On the other hand, the crack propagation and the modes of fracture according to cycle number and the relation of cycle loading to deflection relation and strain relation was observed by fatigue test. As the result of fatigue test, Two-spans Beam without Steel Fibrous was failed at 60~70% of the static ultimate strength and it could be concluded that fatigue strength to two million cycle was around 67.2% by S-N curve. On the other hand, that with Steel Fibrous was failed at 65~85% of the static ultimate strength and it could be concluded fatigue strength to two million cycle around 71.7%.

• Journal of Korean Society of Forest Science
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• v.97 no.6
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• pp.650-655
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• 2008

In an attempt to establish the mass proliferation system, Eucalyptus pellita, a 5-year-old plus tree, was cultured with three different culture types in 1L vessels: solid culture without ventilation (conventional culture), liquid culture without ventilation and open-type liquid culture with forced ventilation. Then the culture scale was subsequently increased from 1L to 10L in vessel volume. After 4 weeks of 1L-scale culture, the best growth was obtained by culturing plantlets on open-type liquid culture, suggesting that the in vitro plantlets growth can be enhanced by liquid medium and ventilation. In open-type large scale culture in 10L vessel, plantlets growth resulted in a 370% increase in the number of nodes, 3.6 times increase in leaf expansion, and 3.3 times increase in shoot length, while the conventional culture suppressed shoot growth due to the callusing on the leaves and lack of $CO_2$. The results indicated that the open-type large scale culture system was effective for enhancing productivity by improving growth of the plantlets in clonally proliferated plus tree, Eucalyptus pellita.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.9
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• pp.1248-1256
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• 1993

The propagation and delay properties in opical fiber are particularly attractive because digital signal processing and conventional analog signal processing techniques such as those using surface acoustic wave devices are limited In their usefulness for signal bandwidth exceeding one or two GHz, although they are very effective at lower frequencies. Since an accurate, low loss and short time delay elements can be obtained by using such an optical fiber, optical signal precessing has attracted much attention for high speed and broad-band signal precessing in particular channel separation filtering for optical FDM signals. In this paper, we consider a coherent optical lattice filter, which uses coherent light sources and consists of directional couplers and optical fiber delay elemnts. The optical fiber fitters are more restricted than the usual digital filters. The reasons are as follows. 1) the coupling coefficients of directional couplers are restricted to the number between 0 and 1. 2) optical signal E(complex amplitude) is divided into J If-$\boxUl$ and J L/7$\div$$\boxUl$ at the directional coupler. Considering these restrictions and in this case all the coupling coefficients of summing and branching elements are set to be equal, we have given design formulae for optical lattice filter, which make the best use of optical signal energy.

• The KIPS Transactions:PartD
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• v.9D no.6
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• pp.1017-1024
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• 2002

According as mobile computing environment is generalized by development of wireless networking technology and communication device, mobile host uses local cache for extensibility and early response time. and reduction of limited bandwidth. This time, between mobile host and mobile support station cache need consistency interested person of done data accordingly much techniqueses propose. Existent consistency techniques because detection based techniqueses are used mainly and broadcast periodic invalid message considering frequent disconnection. However, these techniqueses increase abort step through increase or delay of transmission message number by accuracy examination of data. Therefore, because mobile host deletes cached data, and extensity are decreased. Techniques that is proposed in this paper did to perform refering update frequency about object that page request or when complete update operation happens to solve these problem. Therefore, have advantage that response is fast because could run write intention declaration or update by update frequency electively asynchronously when update operation consists and abort step decreases. Also, improved extensity running delete or propagation electively according to update frequency about periodic invalid message gone since disconnection.

• Journal of Distribution Research
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• v.15 no.5
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• pp.61-79
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• 2010

As the interest and the importance of environmental protection increases rapidly, the environment considers to be not only the item that requires a control and a duty fundamental element but the fundamental element to enhance the internection icompetitiveness n so. Along with the collapse of the foreign trade barrier and the quality improvement of a customer's life qu life of a an object is shortened liforder to sectsfy the customer's lemands and as the result of it quaother critical issues rmparding the waste treatment and recasles are now thought to be momentou onlyaddition to the issue of the greenhou e gases reduction that is considered as one of me q issues among many internection ienvironmental issues. To keep up the pace with the environmental flow qube notd countries have nlreal iput their attempts to solve this environmental problems through a number of rmpulactios and acctios and they have showed a great concern for it as it is an internection iproblem that they should aasroaeronlythe aspect of not just a compan isr a country but of the wte e globn ivillage. Sueroenvironmental flow alemaned the logistic stratmpy of a compan iand it brought up the demand for the reverse logistics in a supply chain. For the reason above, the concept of reverse logistics and classification, the comparison with any similar concepts and its necessity are studied in this research through the theoretical consideration and the current state of the reverse logistics is organized in this research by acknowledging the domestic development process and the properties regarding the recycles of resources. In addition, the way to apply to the nation was investigated by comparing with the environmentalism development process, the reverse logistics policies and examples of advanced countries in logistics. The research proposed building of intimate cooperative system between a shipper and logistic service provider for the reverse logistics throughout the whole supply chain, the financial support, amendment of regulations, support Eco-friendly logistic technology development and the propagation, effective logistic system development and others and it is expected to bring a significant meaning to the reverse logistic policy and operation later on.

• Journal of Korean Society of Steel Construction
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• v.20 no.6
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• pp.723-730
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• 2008

Due to the higher ratio of live load to total loads of railway bridges, the accumulated damage by cyclic fatigue is significant. Moreover, it is highly possible that the initiated crack grows faster than that of highway bridges. Therefore, it is strongly needed to assess the safety for the accumulated damage analytically. The initiation and growth of fatigue-crack are related with the stress range, number of cycles, and the stiffness of the structural system. The stiffness of the structural system includes uncertainties of the planning, design, construction and maintenance, which varies as time goes. In this study, the authors developed the design and risk assessment techniques based on the reliability theories considering the uncertainties in load and resistance. For the probabilistic risk assessment of crack growth and the remaining life of the structures by the cyclic load of railway and subway bridges, response surface method (RSM) combined with first order second moment method were used. For composing limit state function, the stress range, stress intensity factor and the remaining life were selected as input important random variables to the RSM program. The probabilities of failure and the reliability indices of fatigue life for the considered specimen under cyclic loads were evaluated and discussed.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.6
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• pp.531-537
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• 2016

The damage and fracture of machine or structure are caused by the crack happened from the defect existed at the inside of material. The properties of crack propagation and growth characteristic must be considered because there are many cases at which these cracks are densely existed. Therefore, this study investigates the fracture property due to the position of crack and hole inside the standard compact tension (C. T.) specimen. When the concentrated load is applied eccentrically at the standard C. T. specimen, the fracture mechanical behavior due to the existence or non-existence and the position of hole near crack is investigated. As the result of analysis study, model 3 (in case of the distance of 2mm on the horizontal direction between the end part and hole as the specimen model existed with one hole near the crack) has the maximum deformation, stress and deformation energy of the most values among three models. As the distance between the crack and hole inside the specimen becomes nearer, the maximum stress becomes higher in cases of three models. Apart from the number of holes, it is seen that the maximum stress becomes higher near the crack when the hole exists near the crack inside the specimen. If the hole inside the machine or the mechanical structure is punctured by using the result of this study, it is thought that the occurred breakage or breakdown can be prevented by reducing the fracture stress happened at the specimen.

• Journal of Life Science
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• v.19 no.6
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• pp.832-835
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• 2009

The main objective of this research was to improve rooting of M.9 apple rootstock through layering time, shading, layering material and water content of the layering part. Among the treatments, rooting was improved by mother plant shading or an earlier covering (layering in shoot length 2 cm) of shoots. Rooting and root growth of sawdust, chaff or vermiculite treatments were significantly higher than those of the control (soil). In the study of layering material water content, -40 kPa treatment increased rooting ratio, number of roots and root growth compared to -60 kPa treatment and control. These results suggest that early-covering, layering with sawdust, chaff, or vermiculite, and keeping the water content in the layering part at -40 kPa could improve rooting and root growth in M.9 rootstock propagation.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.1
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• pp.166-173
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• 2014

A noncontact nondestructive testing (NDT) method is proposed to detect the damage of pipeline structures and to identify the location of the damage. To achieve this goal, a scanning laser source actuation technique is utilized to generate a guided wave and scans a specific area to find damage location more precisely. The ND: YAG pulsed laser is used to generate Lamb wave and a piezoelectric sensor is installed to measure the structural responses. The measured responses are analyzed using three dimensional Fourier transformation (3DFT). The damage-sensitive features are extracted by wavenumber filtering based on the 3D FT. Then, flaw imaging techniques of a pipeline structures is conducted using the damage-sensitive features. Finally, the pipes with notches are investigated to verify the effectiveness and the robustness of the proposed NDT approach.