• Journal of the Korean Society of Radiology
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• v.83 no.5
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• pp.1141-1146
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• 2022

Extraskeletal osteochondroma, a variant of chondroma, typically arises in the para-articular location of hands and feet. It is a rare disease and is particularly uncommon when joint components are not involved or localized away from joints. Herein, we report a case of extraskeletal osteochondroma in the posterior neck of a 66-year-old female. The characteristic radiologic finding of our case is presented, along with the typical findings of the disease and review of related literature reports.

• Journal of the Institute of Convergence Signal Processing
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• v.24 no.3
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• pp.166-171
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• 2023

Efficient energy management is a very important factor in sensor networks with limited resources, and cluster techniques have been studied a lot in this respect. However, a problem may occur in which energy use of the cluster header is concentrated, and when the cluster header is not evenly distributed over the entire area but concentrated in a specific area, the transmission distance of the cluster members may be large or very uneven. The transmission distance can be directly related to the problem of energy consumption. Since the energy of a specific node is quickly exhausted, the lifetime of the sensor network is shortened, and the efficiency of the entire sensor network is reduced. Thus, balanced energy consumption of sensor nodes is a very important research task. In this study, factors for balanced energy consumption by cluster headers and sensor nodes are analyzed, and a balancing distribution clustering method in which cluster headers are balanced distributed throughout the sensor network is proposed. The proposed cluster method uses multi-hop routing to reduce energy consumption of sensor nodes due to long-distance transmission. Existing multi-hop cluster studies sets up a multi-hop cluster path through a two-step process of cluster setup and routing path setup, whereas the proposed method establishes a hierarchical cluster routing path in the process of selecting cluster headers to minimize the overhead of control messages.

• Journal of The Korean Society of Grassland and Forage Science
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• v.26 no.4
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• pp.285-292
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• 2006

This study was conducted to evaluate the dry matter yield and forage quality of Kenaf in relation to planting density and growing days in Cheorwon area from 20 May to 12 September in 2005. The experiment was laid out in a split plot design with three replications. The main plots consisted of planting density and growing days with three cultivars of Kenaf as sub-plots; Bowling, Everglade and Tainung. The results obtained were summarized as follows. The dry matter yield increased until 92 days after planting at $10{\times}10cm^2$ planting density, but decreased after the day. The dry matter yield increased with maturity in all three cultivars, especially Dowling showed the highest dry matter yield at each harvest time. The Crude Protein (CP) contents of all three cultivars decreased with maturity. Especially, the decrease in the CP contents was greater in the early stage than in the late stage. The planting density did not affect the CP contents, even though they are little higher in $10{\times}20cm^2$ planting density. The higher CP contents were obseued in Dowling, which is not significant. No difference in the Neutral detergent fiber (NDF) and Acid detergent fiber (ADF) contents was observed in the planting density and cultivar, although the increasing tendency was found with maturity. These results suggest that Kenaf can be a good potential forage crop in the northern area of Korea, especially Dowling showed the great dry matter yield and forage quality when harvested on Day 104 at $10{\times}20cm^2$ planting density.

• Journal of Radiation Protection and Research
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• v.22 no.3
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• pp.207-218
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• 1997

Purpose: The objective of this study is to develop an algorithm for estimation of tumor dose using measured transmission dose as a part of the development of on-line dosimetry system. Materials and Methods: Data of transmission dose were measured under various FS, Tp and PCD with a special water phantom for 6 MV and 10 MV X-ray. SCD (source-chamber distance) was set to 150 cm. Measurements were conducted with a 0.125 cc ion chamber. Results: Using measured data and regression analysis, two algorithms were developed for estimation of expected reading for measured data. Algorithm 1 consisted of the quadratic function of PCD and the tertiary function of AlP (area-perimeter ratio). Algorithm 2 consisted of the tertiary function of log(A/P)and the tertiary function of PCD. Algorithm 2 required less data set and was more accurate in comparing expected and observed dose. Conclusion: Using the algorithm developed, transmission dose can be estimated for any exposure condition, i.e. any given Tp, PCD and FS with high accuracy. To complete this algorithm, further developments are needed regarding the beam modifying device, the tissue inhomogeneity and the irregular body surface.

• Journal of the Earthquake Engineering Society of Korea
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• v.10 no.3 s.49
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• pp.101-111
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• 2006

This paper proposes a method for modeling new fault ground motion due to moderate size earthquakes in Stable Continental Regions (SCRs) for the first time. The near fault ground motion is characterized by a single long period velocity pulse of large amplitude. In order to model the velocity pulse, its period and peak amplitude need be determined in terms of earthquake magnitude and distance from the causative fault. Because there have been observed very few new fault ground motions, it is difficult to derive the model directly from the recorded data in SCRs. Instead an indirect approach is adopted in this work. The two parameters, the period and peak amplitude of the velocity pulse, are known to be functions of the rise time and the slip velocity. For Western United States (WUS) that belongs active tectonic regions, there art empirical formulas for these functions. The relations of rise time and slip velocity on the magnitude in SCRs are derived by comparing related data between Western United States and Central-Eastern United States that belongs to SCRs. From these relations, the functions of these pulse parameters for NFGM in SCRs can be expressed in terms of earthquake magnitude and distance. A time history of near fault ground motion of moderate magnitude earthquake in stable continental regions is synthesized by superposing the velocity pulse on the for field ground motion that is generated by stochastic method. As an demonstrative application, the response of a single degree of freedom elasto-plastic system is studied.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.12
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• pp.54-61
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• 2011

We propose a surveillance-alert system based on optimal placements of PDR(Pulsed Doppler Radar) sensors in USN. By using the detection information of moving target from PDR sensor and by considering the covered detection region and geographical property of the strategic area, three optimal placements of sensors are proposed. The proposed placement are named as the grid type, the linear type and the zigzag type. Also, the surveillance alert system based on three sensor placements are developed. The alert level of the proposed surveillance-alert system are 'Perception', 'Caution', 'Warning' and 'Danger' which are decided by the distance change between the moving targets and the command post. The performace of the developed system is verified via outdoor experiments.

• Journal of the Institute of Convergence Signal Processing
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• v.14 no.1
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• pp.45-50
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• 2013

Sensors have limited resources in sensor networks, so efficient use of energy is important. Representative clustering methods, LEACH, LEACHC, TEEN generally use direct transmission methods from cluster headers to a sink node to pass collected data. If clusters are located at a long distance from the sink node, the cluster headers exhaust a lot of energy in order to transfer the data. As a consequence, the life of sensors is shorten and re-clustering is needed. In the process of clustering, sensor nodes consume some energy and the energy depletion of the cluster headers meet another energy exhaustion. A method of transferring data from cluster headers to the sink using neighbor clusters is needed for saving energy. In this paper, we propose a novel routing method using a multi-hop transmission method in cluster sensor networks. This method uses the topology matrix which presents cluster topology. One-hop routing and two-hop routing are proposed in order to increase the energy efficiency.

• Journal of the Korean Geotechnical Society
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• v.25 no.5
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• pp.17-28
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• 2009

When embankments are constructed on soft clay deposit, unsymmetrical surcharges due to embankments may generate the excessive vertical settlement and lateral deformation of soft clay foundation. The excessive deformations in soft grounds cause not only stability problem of the embankment itself but also that of the adjacent structures. The objectives of this research are to study the deformational behavior of soft ground due to the embankment load with different loading and soil conditions. Five model tests are carried out with different test conditions. From the results of the model tests, it is concluded that the lateral displacement induced by the embankment load occurs in the range of two times of the embankment width from a toe. In addition, the relationship between loading rate, v, and the vertical settlement of the soft ground, ${\Delta}s$, and the lateral displacement at the toe of embankment, ${\Delta}y_m$, is investigated based on the model test results.

• Journal of the Korean Society for Marine Environment & Energy
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• v.4 no.4
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• pp.21-31
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• 2001

When an oil-spilling accident occurs at sea, it is of the primary importance to predict the amount of oil leakage for the swift response and decision-making. The simplest method of oil-leakage estimation is based on the hydrostatic pressure balance between oil inside the tank and seawater outside of leakage hole, that is the so-called Torricelli equilibrium relation. However, there exists discrepancy between the reality and the Torricelli relation, since the latter is obtained from the quasi-steady treatment of Bernoulli equation ignoring viscous friction. A preliminary experiment has been performed to find out the oil-leaking speed and shape. Soy-bean oil inside the inner tank was ejected into water of the outer tank through four different leakage holes to record the amount of oil leakage. Furthermore, a CFD (Computational Fluid Dynamics) method was utilized to simulate the experimental situation. The Wavier-Stokes equations were solved for two-density flow of oil and water. VOF method was employed to capture the shape of their interface. It is found that the oil-leaking speed varies due to the frictional resistance of the leakage hole passage dependent on its aspect ratio. The Torricelli factor relating the speed predicted by using the hydrostatic balance and the real leakage speed is assessed. For the present experimental setup, Torricelli factors were in the range of 35%~55% depending on the aspect ratio of leakage holes. On the other hand, CFD results predicted that Torricelli factor could be 52% regardless of the aspect ratio of the leakage holes, when the frictional resistance of leakage hole passage was neglected.

• Korean Journal of Ichthyology
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• v.19 no.1
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• pp.57-65
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• 2007

A new species of the rajid genus Okamejei is described from a single specimen (295 mm TL) from off Shantou, Gwangdong in the South China Sea. The new species differs from all other congeners in the following combination of characters: snout pointed, dorsal head length 6.7 times interorbital width, tail moderately wide and long, its length 48.5% TL, interdorsal distance less than length of first dorsal fin base, postdorsal tail short as 5.8% TL, small evenly distributed dark brownish spots, without ocelli on dorsal surface of disc, pores of ampullae of Lorenzini on ventral surface distributed from snout tip to distal end of metapterygium, scapulocoracoid high, its height about 1.4 times rear corner height, trunk vertebrae 23, predorsal tail vertebrae 50 and pectoral fin radials 96.