• Journal of Environmental Science International
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• v.21 no.8
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• pp.931-938
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• 2012

The effects were investigated of different lengths and numbers of slitwalls in drainless containers on growth and change in soil moisture volumes on the growth of Diffenbachia amoena 'Marianne' and Begonia rex. Drainless containers filled with amended soil, with square shape ($240mm{\times}240mm$) were used, as well as three different sets of slitwalls (2, 4 or 8, respectively) in addition to non-slitwall containers. Two indoor foliage plants were grown in slitwall containers in randomized blocks with 3 replications in greenhouse conditions, from March to September, 2009. Soil moisture volumes per container were measured by weighing containers every 2 hours during the day. The change in soil moisture volumes showed considerable differences among slitwalls tested in comparison to control containers before and after twice-weekly irrigation. Particularly, the differences in the S2 (195mm, slitwall 2) containers were significantly greater than other containers tested. For Diffenbachia amoena 'Marianne', plant height, length of leaf, dry weight and fresh weight were higher with S2 containers than with those grown in other containers tested. The Begonia rex with the best quality in terms of plant height, length of leaf and width of leaf was grown in S8 (360mm, slitwall 8) containers. Particularly, statistical analysis has indicated that shoot fresh weights of Begonia rex grown in S8 were 3-fold higher than those grown in CS8 containers. The different results obtained within the two species led us to hypothesize a species-specific influence on indoor foliage plant performance. However, plants of both species grown in slitwall containers showed good results compared with plants grown in non-slitwall containers.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.210-211
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• 2009

In this study, we propose characteristics improvement methods according to via hole plating method for FBAR Duplexer with US PCS($T_x$:1850MHz~1910MHz, $R_x$:1930MHz~1990MHz) bandwidth which is used for wireless systems. Also, we designed and fabricated 3.8*3.8*1.8mm size microminiature FBAR Duplexer based on this proposal. First of all, in this study, we fabricated pentagon shape resonators by different size to make filter combination, and their quality factor(Q) are 687 with 6.6% of $k_{eff}^2$. Using this resonators, designed 3*2Type $T_x$ filter and 3*4Type $R_x$ filter. The transmission line, which works as phase shifter, is designed with $210{\mu}m$ in width and 18mm in length Stripline type. Inductor, which is used for matching component, is designed with width of $75{\mu}m$, a technically achievable minimum width. And adopted plating method of filling via hole with conductive epoxy for improved grounding and thermal conductivity. Using these configuration with all of the matching component values, we found Duplexer characteristics of -1.57dB ~ -1.73dB in insertion loss, -56dB in attenuation at 1850MHz~1910MHz of $T_x$ band. Also, found -2.71 dB ~ -3.23dB in insertion loss, -58dB in attenuation at 1930MHz~1990MHz of $R_x$ band.

• Journal of Digital Convergence
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• v.16 no.6
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• pp.197-204
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• 2018

The realistic Visual Effects using fluid simulation in 3D computer graphics are operated as important factors to improve the quality of images. The process of creating realistic motions of water, fire, explosion by controlling each property of fluid is called fluid simulation. In general, the creation of a fluid simulation concentrates on the main simulation work phase, however an effective method for initial set up is important for the main simulation work. The purpose of this study is to analyze the factors involved in the initial emission motion and shape of fluid and propose methods that can efficiently apply this into the initial set up. For the process of the research, first, problems are raised based on related researches, and second, two experiments, 'Dynamic Fluid Emitter Creation' and 'User Design Type Emission Velocity Solution', are conducted for more effective fluid simulation. Through this research, the effective fluid simulation of initial set up phase will be suggested through the user design-type emission control solutions.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2004.06a
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• pp.278-284
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• 2004

The processes for the smelting of a metal product and the solidification of a molten salt were developed respectively to treat the products from the electrochemical reduction process. The method for the separation of a metal product in a magnesia container from the residual. salt and consequent smelting of it to a metal ingot by the multi step heating in vacuum was proposed. The new concept using a dual vessel and a salt valve was also suggested for the solidification of a molten salt into a regular size and shape which is suitable for the transport and measurement. The results obtained in the study will be applied to the design of the hot cell demonstration system of the Advanced Spent Fuel Conditioning Process of KAERI.

• Journal of Power System Engineering
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• v.12 no.6
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• pp.50-55
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• 2008

In general, the swing motion of the crane is controlled and suppressed by activating the trolley motion. In many papers reported by us, we suggested a new type of anti-sway control system of the crane. In the proposed control system, a small auxiliary mass(moving-mass) is installed on the spreader and the swing motion is controlled by moving the auxiliary mass. The actuator reaction against the auxiliary mass applies inertial control forces to the container in order to reduce the swing motion in the desired manner. Futhermore the measuring systems based on image sensor have been proposed also. To obtain the robustness for our control system, $H_{\infty}$ based control techniques and other approach have been applied to suppress swing motion. As well known, the robust control technologies based on $H_{\infty}$ control need complicated and difficult process. In the result, the obtained closed-loop system becomes to high order system which may give us many difficulties to apply it to the real plants. Therefore, we introduce an easy approach which is based on LQ control theory. In this approach, we introduce the frequency dependent weighting matrices which give the system filters to shape frequency characteristics of the controlled system and guarantee the control performance.

• Journal of the Korea Convergence Society
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• v.11 no.8
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• pp.159-163
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• 2020

In this study, the flow analyses around according to the existence or non- existence of the trailer's deflector and the shapes were carried out. In the absence of a deflector, the kinetic energy of the turbulence behind the container also generates higher kinetic energy in a wider area than in the presence of a deflector, which adversely affects the vehicle's driving performance. As a trailer's wind deflector-free model has unstable flow rates around the trailer and high kinetic energy of turbulence than a model with a deflector, it can be thought that the increase of fuel economy can be expected by installing a deflector in the trailer. By applying the study result on flow analysis near trailer due to shape of wind deflector, this study is seen to be suitable for the aesthetic convergence.

• Journal of Environmental Science International
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• v.16 no.10
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• pp.1169-1177
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• 2007

The main objective of this research was to evaluate the effects of process variables which were forming ability, flow displacement, effective stress, effective strain, fluid vector and products defects on manufactured artificial lightweight aggregate made of both incinerated sewage sludge ash and clay by means of the numerical analysis of a rigid-plastic finite element method. CATIA (3D CAD program) was used for an extrusion metal mold design that was widely used in designing aircraft, automobile and metallic molds. A metal forming analysis program (ATES Co.) had a function of a rigid-plastic finite element method was used to analyze the program. The result of extrusion forming analysis indicated clearly that a shape retention of the manufactured artificial light-weight aggregate could be maintained by increasing the extrusion ratio (increasing compressive strength inside of extrusion die) and decreasing the die angle. The stress concentration of metal mold was increased by increasing an extrusion ratio, and it was higher in a junction of punch and materials, friction parts between a bottom of the punch and inside of a container, a place of die angle and a place of die of metal mold. Therefore, a heat treatment as well as a rounding treatment for stress distribution in the higher stress concentration regions were necessary to extend a lifetime of the metallic mold. A deformity of the products could have made from several factors which were a surface crack, a lack of the shape retention and a crack of inside of the products. Specially, the surface crack in the products was the most notably affected by the extrusion ratio.

• Journal of Korean Port Research
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• v.15 no.1
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• pp.37-46
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• 2001

Fuzzy logic control(FLC) is composed of three parts : fuzzy rule-bases, membership functions, and scaling factors. Well-defined fuzzy rule-base should contain proper physical intuition on the plant, so are needed lots of experiences of the skillful expert. When membership functions are considered, some parameters on the memberships function such as function shape, support, allocation density should be selected well. The rule of scaling factors is 'scaling'(amplifying or reducing) for both input and output signals of the FLC to fit in the membership function support and to operate the plant intentionally. To get a better performance of the FLC, it is necessary to adjust the parameters of the FLC. In general, the adaptation of the scaling factors is the most effective adjustment scheme, compared with that of the fuzzy rule-base or membership function parameters. This study proposes the adaptation scheme of the scaling factors. When the adaptation is performed on-line, the stability of the adaptive FLC should be guaranteed. The stable FLC system can be designed with stability analysis in the sense of Lyapunov stability. To adapt the scaling factors for the error signals, the concept of the conventional MRAC would be introduced into slightly modified form. A tracking accuracy of the control system would be enhanced by the modified shape and support of the membership function. The simulation is achieved on the pilot plant with the hydraulic steering control of a UCT(Unmanned Container Transporter) of which modeling dynamics have lots of severe uncertainties and modeling errors.

• Journal of the Korea Safety Management & Science
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• v.15 no.4
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• pp.179-184
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• 2013

An accident from machine work is often fatal to the worker. This accident is mostly preventable through perfect process jig. In case of this machine work, however, the disaster frequently occurred because of the design which is not considered the beginning of product design, post-process and mass process of production. As for sand casting method, this has the merits of the production; the product is easily produced by manual labor. On the other hand, this method has the demerits of a bigger dimensional error contrary to other mass process of production. When the sand casting product is in machine work, there are various problems such as unsafe fix and excessive cutting, product desorption and rapid life depreciation of equipment and tools. Considering the characteristics of sand casting method, it is accepted as difficulty to improve the problems. In this study, it suggests shell mold method for mold instead of the machine work after the sand casting of the circle shape container product. And the surface accomplishes the following average of surface roughness Ra$9.94{\mu}m$ of machine work with the casting of flask mold by shell mold method. In accordance with the simplification of processing process and reducing the average thickness variation by mass production of product with detailed appearance, it has a good influence on safety accident prevention caused by production and damaged product. It is confirmed that making higher degree of size precision of all machine work product is possible to increase the safety and productivity, reduce the processing process and improve environment.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.11a
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• pp.311-316
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• 2004

LMTT (Linear Motor-based Transfer Technology) is a horizontal transfer system for the yard automation. which has been proposed to take the place qf AGV (Automated Guided Vehicle) in the maritime container terminal. the system is based on PMLSM (Permanent Magnetic Linear Synchronous Motor) that consists of stator modules on the rail and shuttle mr. It is desirable to reduce the weight of LMTT in order to control the electronic devices with minimum energy. In this research structural optimization for a mover of shuttle mr is performed to minimize the weight satisfying design criteria the objective function is set up as weight. On the contrary, design variable is considered as transverse, longitudinal and wheel beam's thickness and shape variable determining the dimension toward high direction and the constraints are the stresses.