• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2001.05a
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• pp.435-436
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• 2001

In sand beaches the benthic macrofauna feeding on primary food sources such as detritus and phytoplankton and being prey in turn for top predators such as fishes occupies a key position in the center of food chains. Amphipods are the most productive bentho-pelagic animals (Barnard, 1963) and are commonly consumed by fishes and larger crustaceans (Vetter, 1995). Consequently, amphipods play an important role in energy flow as a trophic link from primary producers to higher consumers(Chiaravalle et al., 1997).

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1517-1521
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• 2007

On this study, technical aspects were reviewed to drill a series of micro holes (${\phi}$0.10) over 200 within a few micron tolerance in diameter and position on the stainless steel material. Dedicated tools & jigs were designed and manufactured and optimum cutting conditions were found. On this micro hole drilling process, guide drill and step feeding were applied to help chip discharge, prevent drill breakage and finally improve the accuracy of positioning and roundness. The processing results indicated that most holes are distributed within a few micron tolerance in diameter and position intervals.

• Journal of Advanced Marine Engineering and Technology
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• v.16 no.3
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• pp.30-41
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• 1992

For the state feedback controller which measures only partial state variables, a state observer can be used to give the estimates of unmeasurable states. In this paper, the delayed state feedback method instead of the state observer for desingning a tracking controller of electro-hydraulic control system is presented. The controller design is based on augmenting the original system by one additional integral and proportional element which compensates for the effect of the integral control and on feeding back the measurable state variables and their delayed values. The performance of the proposed position control system is compared with both that of the full state feedback control system and that of the digital PID control system tuned by the Ziegler-Nichols method and by the parameter readjustment through the computer simulation. And then robustness against unmeasurable constant disturbace and parameter variations during operations is also checked.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.733-737
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• 1996

This paper presents a method to measure tile position and orientation of a prismatic polyhedral object (of unknown width, length, height, and number of vertices) using machine vision. The width, length, and origin of workplace where an object is lying are defined as Preliminary operation. The edges of an object are detected from captured image using least sum of square error. The information of an object is determined from the geometric relationships between edges. As an user interface, a versatile image processing program is developed in several modules, and renders a very useful 3D measurement at a limited constraints when adopted in automation of production process. The flexibility of camera position from the algorithm developrf can be used for automated pick and place operations and feeding workpiece u: ;ing assembly robot.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2006.05a
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• pp.395-398
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• 2006

this paper provides a novel method to start the linear engine coupled linear generator from dead stop to its final steady state operation. This method depends mainly to use the linear generator mounted on the shaft of the linear engine to provide the required thrust force to move and oscillate the linear engine from bottom to top dead centers. It is a cost effective approach to start the internal linear combustion engine using its coupled tubular permanent magnet linear generator proposed here. This linear generator operates in this case in motoring mode, providing the required thrust force by feeding this linear generator phases with currents by using a three phase PWM inverter controlled by position feedback scheme. In order to provide the desired thrust force with specific value and direction, a position feedback is required to control the free piston engine motion through controlling the inverter switches using PWM control scheme.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.19 no.2
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• pp.130-134
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• 1997

The sagittal split ramus osteotomy(SSRO) of the mandible has used one of the most popula methods for the correction of various dentofacial deformities, especially mandibular prognathism. In SSRO, there are produced bony gap following mandible setback because of mandibular flaring. For this reason, the condylar axis may be changed due to bony approximation both segment in three dimension more mesio-laterally. According to change of condylar position, the condition of TMJ structure are changed and change of TMJ symptoms are suggested theoretically, and the correction of malocclusion by SSRO may improve the TMJ symptoms by improvement of feeding difficulties. The pupose of this study was to determine relationship between expected alterations in condylar position and suggested TMJ symptoms produced by change of condylar position. TMJ symptoms of 15patients who had operated SSRO are checked at about postoperative 6 month ranging $5{\sim}11$ month. Anterior-posterior position of condyle which was comparison preoperative with postoperative position, was classified 5 groups. The author tried to identify relationship between positional change of condyle and TMJ discomfort.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1983.05a
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• pp.18.1-18
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• 1983

In 1923 Pierre-Robin first described the triad of micrognathia, glossptosis and high-arched or cleft palate. Respiratory distress is not an uncommon occurrence and requires prompt and appropriate treatment. The syndrome occurs once in approximately 50,000 births. Although the etiology of the syndrome is obscure, it is known that the syndrome probably results from a primary deficiency early in fetal life of mandibular development. The symptoms of airway obstruction develop as the base of the tongue falls posteriorly and approximates the posterior pharyngeal wall because of micrognathia, and is aggravated when the infant is in the supine position. The problems of mild airway obstruction can be solved by keeping the infant in the prone position. In case there are feeding difficulties, prompt glossopexy should be preformed as airway is aggravated, but tracheostomy is best avoided. There is some forms of glossopexy including Douglas operation, the insertion of Kirschner wire and Duhamel suture. We identified micrognathia, glossoptosis and high-arched palate in a 2-month-old infant who was brought to our hospital with complaints of dyspnea and feeding difficulties, and we reports this case, since we think this infant whom we observe after tracheostomy because we found Duhamel suture could not relieve the symptoms of airway obstruction as Pierre-Robin syndrome.

• Korean Journal of Environment and Ecology
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• v.23 no.5
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• pp.418-430
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• 2009

The main purpose of this study is to investigate the relationship between the topography of land and vegetation and the preferred habitat of wintering cranes. Investigations were conducted twelve times in Cheorwon basin, South Korea, during two wintering seasons (12/2005 - 2/2006; 1/2007 - 2/2007). The density of rice grain in the middle of rice paddies was higher than that of the areas along the edge of rice paddies. However it was observed that red-naped cranes preferred to feed along the edges of rice paddies rather than to feed in the middle of the paddies. White-naped cranes, on the other hand, Preferred to feed in the middle of paddies. To be more specific, red-crowned cranes preferred feeding sites such as levees of the paddies or the areas where the level of the rice beds was comparatively more elevated. But the preference of the white-naped cranes turned out to be just the opposite. Another finding was that both red-naped cranes and white-naped cranes preferred concealed areas for their feeding site, and the frequency rate of their feeding in concealed areas has little to do with weather factors. This finding contradicts a widely accepted view that cranes prefer open spaces for their feeding site. Besides, red-crowned cranes, compared with white-naped cranes, preferred to feed in more concealed areas. The frequency rate of feeding in both concealed areas and non-concealed areas had little to do with the size of feeding flocks. There was no difference between a flock of fewer than five cranes and a flock of more than five cranes in terms of frequency rate of their feeding. In conclusion, the result of these investigations indicate that red-naped cranes comparatively prefer concealed areas for their feeding site, and white-naped cranes are less prone to them, and there is no direct connection between their preference of feeding site or frequency and the size of their flock. This is presumed to be the characteristics unique to their individual species.

• Journal of The Korean Society of Grassland and Forage Science
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• v.9 no.2
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• pp.68-76
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• 1989

The effect of characteristic of mixture sowing combination on the development of botanical composition was conducted for 12 years on the meadow experiment. The results of this study were summarized as follows. 1. Festuca pratensis lost the expected position of a dominant species. Its vegetation ratio decreased gradually until the last survey year. 2. Arrhenatherum elatius, known as a typical 2-cutting grasss, developed to a dominant species only in the 3- cutting plot without limitation. 3. Alopecurus pratensis, whose feeding value diminishes rapidly, developed to a dominant species regardless of N-fertilization under the condition of 3-cutting, even though the same small amount of seeding was introduced as usual. 4. Trisetum flavescens which causes calcinose exceeded the 40% of vegetation ratio which was the approved rate for feeding at the high N-level (2OOKgIha). 5. Among the introduced, the species showed the significance in quantity were Lotus corniculafus solely in the 2-cutting plot, and Trifolium repens solely in the 3-cutting plot. In the 3-cutting plot legume yet remained under N-fertilization. 6. The appropriate ratio of vegetation for the subordinate species in the mixture sowing combination was easily attained from the least amount of seeding (Gramineae with max. 3Kg/ha, Leguminosae with max. 2kgIha). 7. Into the mixture sowing combination, infiltrated unintroduced species marked more noticeably in the 2- cutting plot than in the 3-cutting plot.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.13 no.7
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• pp.508-516
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• 2003

The dynamic characteristics of an ell-lubricated, short squeeze film damper (SFD) with a central feeding groove are derived based on a theoretical analysis considering the effect of a groove, and identified experimentally using an Active Magnetic Bearing (AMB) system as an exciter. In order to get the theoretical solution, the fluid film forces of the grooved SFD are analytically derived so that the dynamic coefficients of the SFD can be expressed in terms of its design parameters. For the experimental validation of the analysis, a test rig using an AMB as an exciter is proposed. As an exciter. the AMB represents a mechatronic device to levitate and position the test Journal without any mechanical contact, to generate relative motions of the Journal inside the tested SFD and to measure the generated displacements during experiments with fairly high accuracy. Using this test rig, experiments are extensively conducted with various values of clearance, which Is one of the most important design parameters. in order to investigate its effect on the dynamic characteristics and the performance of the SFD. Damping and Inertia coefficients of the SFD that are experimentally Identified are compared with the analytical results to demonstrate the effectiveness of the applied analysis. It Is also shown that the AMB is an ideal device for tests of SFDs.