• Transactions of the Korean Society of Mechanical Engineers
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• v.10 no.1
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• pp.110-120
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• 1986

45.deg. corss jet flow, at the mixing of two jet flows, was experimentally studied. For this study, only the statistical turbulent characteristics and high order moments will be analysed by on-line computer system (hot-wire anemometer system, dynamic analyser and computer system, plotting and printing system). Since mean velocity distributions, intensities of turbulence, Reynolds stresses, correlation coefficients, and other general results were already studied and presented. One dimensional probability density distributions of u', v', and w' were analysed comparing with Gaussian curve, which showed skew and flat tendency according to the Y and Z directions. For the analysis of the joint flow of turublent components, the joint probability density distributions were examined. The fagures were drawn so as to be read joint probabilities, joint probability densities, fluctuating velocities u', v', and w'. For further detailed examination of the variations of skewness and flatness phenomena, iso-joint probability density contours obtained from the profiles of the joint probability density distributions were studied. According to the displacement of positions from the center of the mixing flow and the directions, the flatness and skewness factors were increased.

• Journal of muscle and joint health
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• v.22 no.3
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• pp.160-166
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• 2015

Purpose: The purpose of this study is to examine the effect of leg crossing on reducing orthostatic hypotension and orthostatic hypotension symptoms in hemodialysis patients. Methods: A one-group pretest-posttest design was used. A total of 40 post-hemodialysis adult patients were enrolled, excluding the case of intradialysis hypotension, unbalance of standing with leg crossing, adding antihypertensive medications. Blood pressure (BP) and heart rate (HR) were measured in supine and standing positions. After a week, BP and HR were measured in supine and standing with leg crossing position. Orthostatic hypotension symptoms were also measured by self-reported structured questionnaire in standing without leg crossing and with leg crossing position. Results: We found out that systolic blood pressure, diastolic blood pressure, and mean arterial pressure increased significantly in standing with crossing leg position applied (p=.006, p=.001, p=.006). However, presences of orthostatic hypotension symptoms were not significantly decreased in standing with leg crossing position (p=.500, p=.318, p=.306, p=.241, p=.356, p=.500, p=.241, p=.308). Conclusion: This study shows that leg crossing is effective for reducing orthostatic hypotension without additional cost or instruments. Leg crossing as one of the preventive interventions to reduce orthostatic hypotension is easier and simpler to be implemented in hemodialysis patients.

• Proceedings of the KSME Conference
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• 2001.11b
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• pp.764-769
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• 2001

Recently, according to increase in the requirement of electric power, a thermoelectric power plant equipped with pulverized coal combustion system is highly valued, because coal has abundant deposits and a low price compared with others. For efficient use of coal fuel, most of plant makers are studying to improve combustion performance and flame stability, and reduce pollutant emission. One of these studies is how to control the profile of particle injection and velocity dependant on coal nozzle. Basically, a mixed flow of gas and particle in coal nozzle is required to have appropriate injection and concentration distribution at exit to achieve flame stability and low pollutant, but it is very difficult to obtain that without help of a coal separating device within nozzle. In this study, each distribution of air and coal flow rate is measured for the coal nozzle with coal separator developed by us. The coal concentration at exit is various according to inlet swirl values and positions of coal separator. Also pressure drop is measured for various operating conditions of this nozzle. From these results, we can find the separation characteristic of new developed coal separator, and select proper operation range of coal nozzle. When this coal nozzle is applied to actual plant, these investigations will be very useful to confirm the shape of coal separator to have efficient particle injection.

• Journal of Mechanical Science and Technology
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• v.17 no.12
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• pp.1835-1843
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• 2003

This paper introduces the development of the caliper system for a geometry PIG (Pipeline Inspection Gauge). The objective of the caliper system is to detect and measure dents, wrinkles, and ovalities affect the pipe structural integrity. The developed caliper system consists of a finger arm, an anisotropic permanent magnet, a back yoke, pins, pinholes and a linear hall effect sensor. The angle displacement of the finger arm is measured by the change of the magnetic field in sensing module. Therefore the sensitivity of the caliper system mainly depends on the magnitude of the magnetic field inside the sensing module. In this research, the ring shaped anisotropic permanent magnet and linear hall effect sensors were used to produce and measure the magnetic field. The structure of the permanent magnet, the back yoke and pinhole positions were optimized that the magnitude of the magnetic field range between a high of 0.1020 Tesla and a low of zero by using three dimensional nonlinear finite element methods. A simulator was fabricated to prove the effectiveness of the developed caliper system and the computational scheme using the finite element method. The experimental results show that the developed caliper system is quite efficient for the geometry PIG with good performance.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.5
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• pp.775-784
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• 2008

It is not easy to access very high speed Internet services at sea due to some technical and economical problems. In order to realize the very high speed Internet services at sea like on land, new communication network models based on MANET should be adopted. In this paper, a new MANET model at sea is provided, which considered the ocean environments, and the characteristics and movement of vessels. On the basis of the fact that most vessels navigate on the predetermined courses, which are the shortest paths between source and destination ports in most cases, a type of location oriented routing protocol is proposed in this paper. The Hybrid Course-Based Routing Protocol(HCBR) makes use of the static information such as courses and positions of ports to proactively find the shortest paths not only among ports but also the cross points of courses. HCBR also makes use of the locational information of vessels obtained via GPS and AIS systems to reactively discover the shortest route by which data packets are delivered between them. We have simulated the comparison of the performance of HCBR with those of LAR scheme 1 and scheme2, the most typical protocols using geographical information. The simulation results show that HCBR guarantees the route discovery even without using any control packet. They also show that HCBR is more reliable(40%) and is able to obtain more optimal routes(10%) than LAR scheme1 and scheme2 protocols.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.189-191
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• 2002

In the proton therapy using a gantry system, periodical verification of iso-center position is very important to assure precision of patient positioning system at any gantry angles in proton treatment. In the gantry system, there are three different types of iso-center; 1) in a geometrical view, 2) in an X-ray beam's eye view, 3) in a proton beam's eye view. Idealistically, they would be an identical point. They could, however, be different points. It may be a source of errors in patient positioning. At PMRC, we have established a system of verification for iso-center positions using a stainless ball of 2-cm in diameter and an imaging plate. This system provides the relation among a center of a patient target position, a center of proton irradiation field, and/or a center of X-ray field in accuracy of 50$\square$m in the 2) and 3) views, as images of a center of the stainless ball and a center of a 100 mm${\times}$100 mm-aperture brass collimator recorded on the imaging plate, which is setup at 1-cm behind the ball. In addition, it provides simultaneously the images of the ball and the collimator on an imaging intensifier (II), which is setup downstream of the proton or X-ray beam. We present a method of quality assurance (QA) for calibration of iso-center position in a rotation gantry system at PMRC and the performance of this system. A proton beam position on the 1$\^$st/ scatterer in the nozzle of the gantry affects less sensitive (reduced by a factor of 1/5) to the results of the iso-center position. The effect is systematically correctable. The effect of the nozzle (or the collimator) position is less than 0.5 mm at the maximum extraction (390 mm).

• Archives of Plastic Surgery
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• v.38 no.1
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• pp.102-104
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• 2011

Purpose: The standard treatments of hand fractures today are fixations by K -wires, metal plates, wires and lag screws. But it is very difficult to reconstruct fractures by placing implants into small bony fragments especially in the comminuted fractures and intra-articular fractures. This paper describes a simple method of reconstruction with Histoacryl$^{(R)}$ for comminuted and intra-articular fractures in hands. Methods: 2 cases with comminuted and intra-articular fractures by crushing injury were reconstructed with Histoacryl$^{(R)}$. We performed applying Histoacryl$^{(R)}$ with swab on the bone cortex carefully to avoid Histoacryl$^{(R)}$ infiltrating into the medulla. We could rearrange and fixate bony fragments using only Histoacryl$^{(R)}$, in addition, metal plates, K-wires, wires, and lag screws could be used for secondary fixation if needed. Results: Post-operative X-ray finding of 2 patients assured that the bony fragments of the hand fractures maintained their original positions. Significant displacement and deviation, infection, nonunion, and malunion during the follow-up period were not observed. Conclusion: This study showed the possibility of using Histoacryl$^{(R)}$ in addition as a simple method of fixation in the comminuted and intra-articular hand fractures.

• Proceedings of the KSPS conference
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• 2007.05a
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• pp.71-73
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• 2007

The Purpose of the study is to give Korean-English leaners better knowledge on vowel sounds in their learning English. The traditional description of the cardinal vowel system developed by Daniel Johns in 1917 is not enough to provide English learners with clear ideas in producing native like vowel sounds. For the reason, three Korean-native subjects, one male, one female and one child are chosen to produce 7 cardinal vowels and compare them with native English and American speaker's vowel sounds. The difference of produced vowels sounds is quantified and visualized by employing Sona-match program. The results have been fairly remarkable. Firstly, Korean-English learner's vowel sounds are articulated differently from their intention of vowel production. Secondly, the tongue positions of Koreans are placed slightly more down and forward to the lips than those of English and Americans. However, the front vowel /i/ sound is quite close to English and Americans. Lastly the mid-vowel /${\partial}$/ sound is not produced in any articulations of Korean-native speakers. It is thought that the mid vowel, /${\partial}$/ is a type of a weak sound regarded as 'schwa' which needs a great deal of exposure to the language to acquire a physical skill of articulation.

• The Journal of Korean Physical Therapy
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• v.23 no.5
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• pp.15-21
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• 2011

Purpose: The purpose of this study was to describe the influence of respiration on the segmental motion of the lumbar spine in the lying position. Methods: Twelve healthy females without a history of low back pain participated. Lumbosacral lordosis, intervertebral body angles, intervertebral body displacements, and anterior heights of the intervertebral disc of the lumbar spine were measured at inspiration, expiration and forced expiration in the supine and prone positions via fluoroscopy. Results: The results of lumbar kinematic analysis in the supine position according to respiration pattern were as follows. The L4/5 intervertebral body angle was significantly higher at forced expiration than at expiration (p<0.05). The L3/4 anterior height of the intervertebral disc was significantly higher at expiration than at forced inspiration and the L5/S1 anterior height of the intervertebral disc was significantly higher at inspiration than at forced expiration (p<0.05). There were no significant differences in the intervertebral body displacements and lumbosacral lordosis in the supine position (p>0.05). The results of lumbar kinematic analysis in the prone position according to respiration pattern were as follows. The L5/S1 anterior height of the intervertebral disc was significantly higher at inspiration than at forced expiration (p<0.05). However, there was no significant difference in the intervertebral body angle, the intervertebral body displacements, and the lumbosacral lordosis (p>0.05). Conclusion: These findings suggested that respiration can affect the intervertebral body angle and anterior height of the intervertebral disc in some segments. The results from this study serve as a step in the development of guidelines for lumbar kinematic analysis for lumbar breathing training.

• Journal of the Korean Society for Library and Information Science
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• v.44 no.4
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• pp.457-477
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• 2010

Currently, collections with public libraries are evaluated only on the basis of simple data, such as the use volume of collections with individual libraries, and interlibrary lending (ILL) results. To promote the ILL of regional libraries and raise the use of collections, however, the evaluation of collections should be expanded from individual libraries to regional libraries. This study aims to propose user-oriented methods for evaluating the library collections within a regional library system by using four kinds of data: collection, acquisition, circulation, and ILL application data. The results of this study show that the proposed method can reveal the positions of each library within a regional library system, and also the characteristics of a library's collections and users' needs more precisely.