• The Journal of Engineering Geology
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• v.20 no.2
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• pp.183-189
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• 2010

Fault gouge samples were collected from the fault cores of the boundary faults between the Cretaceous Basement and the Tertiary Waeup Basin. Fractal dimensions (D) were obtained by using survivor grains which were analysed from six thin sections of the gouges under the optical microscope. The elliptical survivor grains show a shape preferred orientation almost parallel to clay foliation in matrix, suggesting that it was formed by the rotation of the survivor grains in abundant fine-grained matrix during repeated fault slips. The size distributions of the survivor grains follow power-laws with fractal dimensions in the 2.40-3.02 range. D values of all samples but one are higher than a specific D value equal to 2.58 which predicts the self similarity of fragmentation process in constrained comminution model (Sammis et al., 1987), which indicates large fault slip and multiple faulting. Probably the higher D values than 2.58 mean the non-self-similar evolution of cataclastic rocks where fragmentation mechanism changed from constrained comminution to the grain abrasion accompanying selective fracture of larger grains.

• Clinics in Shoulder and Elbow
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• v.10 no.1
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• pp.33-41
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• 2007

Purpose: The purpose of this study was to prove the effectiveness of the open medial (glenoid-based) anterior-inferior capsular shift in patients with multidirectional shoulder instability. Materials and Methods: We reviewed 19 patients treated by medial anterior-inferior capsular shift for multidirectional shoulder instability from March, 1998 to December, 2003. 15 patients of them have experienced recurrent dislocation. 8 patients(42%) showed bilateral laxity and 11 patients(58%) generalized ligamentous laxity, and 2 patients(10.5%) voluntary subluxation. An average follow-up was 24 months (range : $9{\sim}32$ months). Results: Pain improved in 18 patients of all. There was an average loss of 10 degree of external rotation, but no limitation of activity of daily living. There was no redislocation and subluxation, but two patients had some apprehension in sports activity. With Rowe score, the result was excellent or good in all patients. There were hematoma and local skin problem in 1 patient, but all had healed up. Conclusion: Medial anterior-inferior capsular shift in multidirectional shoulder instability provided satisfactory results in pain relief, patient's satisfactions and stability of glenohumeral joint. Though some of them have anterior gleniod deformities and large Hill-Sachs lesions, we could get good stabilities.

• Korean Journal of Clinical Laboratory Science
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• v.48 no.4
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• pp.296-303
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• 2016

This study was performed to evaluate the effect of hemoglobin (Hb) on bone mineral density (BMD) in university students by performing a quantitative analysis. The subjects included healthy university students aged 20 to 30 years. Although osteoporosis has traditionally been considered as a disease of aging women, it is becoming an increasingly concerning male health problem. Diagnosis of osteoporosis is calculated with a quantitative assessment of BMD. Laboratory blood and urine tests are mainly used with low BMD or fragility fractures to identify any possible causes of bone metabolism disorders. In this study, there was no difference in BMD according to gender. The average red blood cell (RBC), Hb, and Hematocrit (HCT) were significantly higher in males (p<0.01). The correlation between lumbar spine, skeletal muscle mass (SMM), and basal metabolic rate (BMR) was statistically significant (p<0.01). Hb showed a 51.7% statistical influence on BMD by multiple regression analysis. These findings are useful to understand the relationship between BMD and Hb; lower Hb level is associated with lower BMD. The Hb level was the strongest predictor of abnormal BMD. In conclusion, this study showed that a low Hb value was significantly correlated with low bone mass, suggesting that a low Hb value is a risk factor for changes in bone turnover that leads to a decrease bone density.

• Korean Journal of Food Science and Technology
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• v.23 no.1
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• pp.88-92
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• 1991

To analyze the effects of the system parameters on the target parameters, which include the amount of water evaporation, water solubility index(WSI) and water absorption index(WAI), test trials of fractional factorial design of the three process variables at three levels were carried out for corn grit with a laboratory twin-screw extruder with three different screw configurations. The system parameters collected from the trials, such as extrusion temperature, specific mechanical energy input(SME) and mean residence time(RT), were showed the ranges of $129{\sim}182^{\circ}C$, $67{\sim}163\;kwh/ton$ and $12{\sim}34\;sec$, respectively. Within these ranges of the system parameters, the target parameters were able to be quantified by using multiple regression equations. The correlation of results with the system parameters blocked by the screw configuration as dependent variables, yield correlation coefficients above 0.90, and the correlation using the system parameters obtained from whole experiment system as the dependent variables yield correlation coefficients around 0.80. The functional relationship, which can be quantified by second order polynomial regression equation with only two system parameters within necessary degree of accuracy, can he graped in three dimensional surface response and contour diagrams.

• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.3
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• pp.475-488
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• 2017

Wear prediction of TBM disc cutters is a very important issue for hard rock TBMs as number of cutter head intervention. In this regard, some model such as NTNU, Gehring model, CSM models have been used to predict disc cutter wear and intervention interval. There are some deficiencies in these models. This paper developed a new test method for wear prediction for TBM disc cutter and proposed a new abrasion index. In this regard, different abrasivity indices along with their testing methods are explained. A comparative study is performed to develop the predictability of different cutter life evaluation methods and index. The evaluation of the new methods proposed in this paper shows a very good agreement with the actual cutter life and intervention interval length. The proposed tester and index can be easily used to predict the intervention interval length and cutter wear evaluation in both planning and construction stages of a TBM tunneling project.

• Journal of KIISE:Software and Applications
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• v.36 no.2
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• pp.161-168
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• 2009

In this paper, we develop an Intelligent Wheelchair(IW) control system for the people with various disabilities. The aim of the proposed system is to increase the mobility of severely handicapped people by providing an adaptable and effective interface for a power wheelchair. To facilitate a wide variety of user abilities, the proposed system involves the use of face-inclination and mouth-shape information, where the direction of an Intelligent Wheelchair(IW) is determined by the inclination of the user's face, while proceeding and stopping are determined by the shape of the user's mouth. To analyze these gestures, our system consists of facial feature detector, facial feature recognizer, and converter. In the stage of facial feature detector, the facial region of the intended user is first obtained using Adaboost, thereafter the mouth region detected based on edge information. The extracted features are sent to the facial feature recognizer, which recognize the face inclination and mouth shape using statistical analysis and K-means clustering, respectively. These recognition results are then delivered to a converter to control the wheelchair. When assessing the effectiveness of the proposed system with 34 users unable to utilize a standard joystick, the results showed that the proposed system provided a friendly and convenient interface.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.2
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• pp.240-245
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• 2016

This paper describes the rheological behavior study such as viscosity and change of shear stress regarding marine lubricating oil according to the amount of Marine Gas Oil (MGO) dilution. The viscosity reduction due to fuel dilution is crucially important characteristic to decreasing engine durability because of the abrasion of piston ring or liner. The lubricating oil used in this paper was blended with magnetic stirrer diluted High Sulfur Diesel (HSD, 0.05 wt%) ratio of 3 %, 6 %, 10 %, 15 % and 20 %. The viscosity and shear stress of diluted lubricating oil were measured with the temperature range from $-10^{\circ}C$ to $80^{\circ}C$ using a rotary viscometer (Brookfield Viscometer). As the amount of MGO dilution increasing in lubricating oil, the viscosity and stress of those decreased, because the lubricating oil diluted MGO with low viscosity show the trends to decreased viscosity and shear stress. Especially, the viscosity and shear stress of lubricating oil radically decreased at low temperature ($0{\sim}-10^{\circ}C$) and doesn't effect in MGO dilution at over $40^{\circ}C$. As temperature risen, the reduction of the viscosity and shear stress in lubricating oil shows the Newtonian behavior. The lubricating oil was required to check up periodically to improve engine durability since the viscosity reduction by MGO dilution accelerating the engine abrasion.

• Journal of Korean Tunnelling and Underground Space Association
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• v.16 no.2
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• pp.181-191
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• 2014

This study aims to evaluate cutter acting forces as well as axial stresses and torques in the shaft of two kinds of disc cutters including a single disc cutter and a double disc cutter with the same cutter ring geometry in a series of linear cutting tests. From the tests, the mean values of normal forces and rolling forces acting on the double disc cutter were approximately twice as high as those from the single disc cutter. Similarly, the mean values of axial stresses in the shaft of the double disc cutter were also twice as high as those from the single disc cutter even though the comparisons of torques from two kinds of disc cutters were insignificant since they showed very low values. However, it is necessary to take the durability of a tapered roller bearing used for the double disc cutter into high consideration since the average normal force from the double disc cutter exceeds the allowable force for a disc cutter with the diameter of 432 mm (17 inches). Finally, there is no practical problem in terms of axial stresses in the shaft of the double disc cutter since they are much lower than the yielding stress of the cutter shaft material, even though the axial stresses in the shaft of the double disc cutter are approximately twice as high as those from the single disc cutter.

• Journal of KIISE:Computing Practices and Letters
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• v.9 no.3
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• pp.341-351
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• 2003

Digital image watermarking is the method that can protect the copyright of the image by embedding copyright information, which is called watermark. Watermarking must have robustness to intentional or unintentional data changing, called attack. The conventional watermarking schemes are robust to waveform attacks such as image compression, filtering etc. However, they are vulnerable to geometrical attacks such as rotation, scaling, translation, and cropping. Accordingly, this paper proposes new watermarking scheme that is robust to geometrical attacks by using invariant centroid. Invariant centroid is the gravity center of a central area in a gray scale image that remains unchanged even when the image is attacked by RST including cropping and proposed scheme uses invariant centroids of original and inverted image as the template. To make geometrically invariant domain, template and angle compensated Log -Polar Map(LPM) is used. Then Discrete Cosine Transform(DCT) is performed and the watermark is embedded into the DCT coefficients. Futhermore, to prevent a watermarked image from degrading due to interpolation during coordinate system conversion, only the image of the watermark signal is extracted and added to the original image. Experimental results show that the proposed scheme is especially robust to RST attacks including cropping.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.4
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• pp.451-456
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• 1995

To elucidate the intrinsic rheological properties of carboxymethyl chitin (CM-chitin) from the shell of red snow cyab (Chinonecetes japonicus), the configuration and polyelectrolyte behavior of CM-chitin in low concentration solution were investigated. Unperturbed dimensions were ranged from $127{\AA}\;to\;113{\AA}$ as root mean square end-to-end distance$(r_0)$, $52{\AA}$ to $46{\AA}$ as radius of gyration$(S_0)$. The intramolecular expansion tarter(a) was not varied with molecular weight and was 2.1. And effective bond length $(b_0)$ was $14.5{\AA}$. In perturbed condition, Flory constant was $2.35\times10^{21}$. When ionic strength were 0.02 and 1.0, intrinsic viscosity were 1.95dl/g and 1,06 dl/g, respectively. These results suggested that CM-chitin is a polyelectrolyte in aqueous media. At infinite ionic strength, intrinsic viscosity was 0.91dl/g. The intrinsic stiffness of CM-chitin backbone was estimated by evaluating the stiffness parameter (B) as 0.11 and agreed well with the results of k-carrageenan.