• Tribology and Lubricants
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• v.40 no.2
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• pp.61-66
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• 2024

Micro-plastics are synthetic high-differentiation chemicals of less than 5mm in size, and are deposited not only on the sea surface but also on the coast. If these micro-plastics are not properly separated from the sand, they can threaten marine ecosystems. Thus, in the present study, we aimed to apply cyclone separator to the micro-plastic retrieval in order to predict the movement of particles according to the formation of the cyclone separator by applying the centrifugal force of the particle in accordance with the rotational movement of the air. The cyclone separator has three shapes, the first one is a typical interconnected cyclone separator. The second is the horn form, except for the cylinder in a regular cyclone separator, and the third is a form that increases the horn's height twice in the second. The numerical analysis simulation of the Cyclone separator used the Fluent software package. The output speed of the Cyclone separator was 5 to 13m/s at 1m/s intervals. The simulated particles include sand, Styrofoam, PET, PP, and PU. Sand particles are assigned a fixed diameter of 2mm, while other particles have a diameter of 3mm. As a result of the analysis, the first form was not separated from plastic. The Styrofoam separation efficiency in the second showed its highest efficiency at 72.7% at 7m/s, and the efficiency decreased after 12m/s as the sand particles were mixed into the plastic attachment location. In the third form, the separation efficiency of Styrofoam at 12m/s was highest at 67.9%.

• Journal of Ecology and Environment
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• v.31 no.2
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• pp.89-95
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• 2008

Sensing the approach of a predator is critical to the survival of prey, especially when the prey has no choice but to escape at a precisely timed moment. Escape behavior has been approached from both proximate and ultimate perspectives. On the proximate level, empirical research about electrophysiological mechanisms for detecting predators has focused on vision, an important modality that helps prey to sense approaching danger. Studies of looming-sensitive neurons in locusts are a good example of how the selective sensitivity of nervous systems towards specific targets, especially approaching objects, has been understood and realistically modeled in software and robotic systems. On the ultimate level, general optimality models have provided an evolutionary framework by considering costs and benefits of visually elicited escape responses. A recent paper showed how neural network models can be used to understand the evolution of visually mediated antipredatory behaviors. We discuss this new trend towards integration of these relatively disparate approaches, the proximate and the ultimate perspectives, for understanding of the evolution of behavior of predators and prey. Focusing on one of the best-studied escape pathway models, the Orthopteran LGMD/DCMD pathway, we discuss how ultimate-level optimality modeling can be integrated with proximate-level studies of escape behaviors in animals.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.11c
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• pp.85-94
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• 1999

Reinforced Soil Wall has several merits comparing with conventional retaining wall. The conventional method has the limit of wall height, ununiform settlement of the foundation ground, quality assurance of the embankment body, shortening of construction period, economical construction and so on. Basis of previous mentioned things reinforced soil wall is the substitutional method of conventional retaining wall and its necessity is continuously increasing. The embanking material used in reinforced soil wall is generally limited such as a good quality sandy soil, and in many case constructors have to transfer such a good embanking material from far away to construction site. As a result, they would pressed by time and economy. If poor soils could be used embanking material, for example, clayey soil produced in-situ by cutting and excavation, the economical merit of reinforced soil wall would be increased more and more. Likewise, a lot of study about laboratory experimental behavior of reinforced soil wall using a good quality soil is being performed, but is rare study about clayey soil containing much volume of fine particle relatively in korea. In this study, the authors investigated behavior of the geosynthetic reinforced and unreinforced soil walls using clayey soil as embanking material in view of horizontal movement of walls, bearing capacity and reinforcement stress.

• Journal of Korean Tunnelling and Underground Space Association
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• v.5 no.4
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• pp.313-322
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• 2003

This research work presents 3-D behavior of adjacent structures due to tunnelling induced ground movements by means of field measuring data and nonlinear FEM tunnel analysis. The results of the analytical methods from Mohr-Coulomb model are compared with the site measurement data obtained during the twin tunnel construction. It was found that the location and stiffness of the structure influence greatly the shape and pattern of settlement trough. The settlement trough for Greenfield condition was different from the trough for existing adjacent structures. Therefore the load and stiffness of adjacent structures should be taken into account for the stability analysis of the structures.

• Korean Institute of Interior Design Journal
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• v.19 no.6
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• pp.197-205
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• 2010

For the spatial experience of spectators visiting a museum, the route search of trying to follow the spatial structure or production of exhibition and the information search of trying to see are accomplished at the same time. In such process, the spectator's reaction of visual perception produces the result of emotional reaction and action exchanged between human and space by going through the recognition and perception on the target of environment factor. For the spatial experience of a spectator, the reaction of visual perception which interacts according to the exhibit and exhibition environment within space according to viewing purpose, interest and concern of spectator comes out as visual activity which is an activity to understand the spatial information shown as various activities according to spatial structure and unfolding characteristics of the display. The purpose of this study is to identify The Correlation of Spectator Movement Created According to Structural Form of Exhibition Area Based on Interaction between Exhibition Area Structure and Spectator to utilize as basic material while designing museum exhibition using isovist field which is a quantitative analysis tool of spectator's visual behavior and spatial structure at each exhibition area.

• Structural Engineering and Mechanics
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• v.34 no.3
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• pp.335-350
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• 2010

Out of plane behaviors of walls and infills are investigated in this paper, using rigid block concepts. Walls and infills are sometimes separated from top beams because of in plane movement of the walls and crumbling mortar layers under the top beams. Therefore, sufficient strength should be supplied to hold them against out of plane forces. Such walls are studied here under some real and scaled earthquakes, regarding their out of plane behavior. Influences of some reinforcements, connecting the walls to frames or perpendicular walls, are also studied. It is shown that unreinforced walls of regular sizes (3 m high and 4.5 m long) are normally unstable in the earthquakes. However, performing some reinforced bars that connect them to adjacent elements- frames or perpendicular walls - stabilizes them. Eventually, it is concluded that supplying 3 reinforced bars at 1/4, 2/4 and 3/4 of the panel's height stabilizes the walls in the assumed earthquakes. In this regard, for 20 cm and 35 cm thick walls ${\Phi}$18mm and ${\Phi}$20mm bars are to be used, respectively. For walls with other configurations, the forces and required areas of the reinforcements can be determined by the developed method of this paper.

• Fisheries and Aquatic Sciences
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• v.11 no.1
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• pp.61-69
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• 2008

Using empirical data of fish performance and physiological limits as well as physical stimuli and environmental data, a cod-end selectivity model based on a chaotic behavior model using the psycho-hydraulic wheel and neural-network approach was established to predict fish escape or herding responses in trawl and cod-end designs. Fish responses in the cod-end were categorized as escape or herding reactions based on their relative positions and reactions to the net wall. Fish movements were regulated by three factors: escape time, a visual looming effect, and an index of body girth-mesh size. The model was applied to haddock in a North Sea bottom trawl including frequencies of movement components, swimming speed, angular velocity, distance to net wall, and the caught-fish ratio; simulation results were similar to field observations. The ratio of retained fish in the cod-end was limited to 37-95% by optomotor coefficient values of 0.3-1.0 and to 13-67% by looming coefficient values of 0.1-1.0. The selectivity curves generated by this model were sensitive to changes in mesh size, towing speed, mesh type, and mesh shape.

• Journal of the Korean Institute of Intelligent Systems
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• v.15 no.6
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• pp.682-687
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• 2005

Behavioral sequences of the medaka(Oryzias latipes) were investigated through an image system in response to medaka treated with the insecticide and medaka not treated with the insecticide, diazinon(0.1 mg/1). After much observation, behavioral patterns could be divided into 4 patterns: active smooth, active shaking, inactive smooth, and inactive shaking. These patterns were analyzed by 5 features: speed ratio, x and y axes projection, FFT to angle transition, fractal dimension, and center of mass. Each pattern was classified using decision tree. It provide a natural way to incorporate prior knowledge from human experts in fish behavior, The main focus of this study was to determine whether the decision tree could be useful in interpreting and classifying behavior patterns of the animal.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.1024-1031
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• 2006

In this study using the finite different programs, FLAC2D to define affection of the soil-structure interface in evaluating the behavior of adjacent structures according to excavation, and tried to compare each the results of different 46 cases which were various condition of stories, length and locations from the excavation site. In the result of the numerical analysis, the affection of the interface was affected by the building stories, locations from the excavation site and shape ratio(length/height). Therefore, in the considering soil-structure interaction in the damage assessment and the behavior of the adjacent structures when excavation, is important in more accurate evaluation of the movement of structure. Also, the interface modification factor were proposed which can consider the interface.

• Korean journal of applied entomology
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• v.28 no.4
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• pp.221-228
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• 1989

The oviposition behavior of Ooencyrtus kuvanae (Howard) (Hymenoptera: Encyridae) was examined in a small petri dish containing eggs of gypsy moth, Lymantrt'a dt'spar L. The behavioral sequence from initial searching movement toward the host egg through oviposition, departure, and auxiliary phase activities such as resting, glooming, and host feeding were described. Oviposition experience shortened the approach time to subsequent eggs. The time spent for contacting the host egg also decreased with oviposition experience. Oviposition experience may play an important role in host recognition and increasing oviposition efficiency.