• The Journal of Engineering Geology
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• v.24 no.1
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• pp.123-135
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• 2014

Earthquakes can cause serious loss of life and significant property damage. Thus, the study of active faults is important in evaluating future fault activity and hazards caused by future earthquake events. Structural mapping and the tracing of active faults are the primary steps in studies of active faults. Until now, active faults in South Korea have been mapped using aerial photography, satellite images, and low-quality DEMs. Lineament analysis as a means of identifying active faults is relatively difficult in Korea due to geological characteristics (weak tectonic activity) and dense vegetation cover. In this paper, we introduce the basic concept of the LiDAR technique (a new prospective remote sensing method) and a data analysis method that can overcome these problems. This paper will contribute to a better understanding of the airborne LiDAR technique and its application to South Korea. Some preliminary results from Korean and USA LiDAR data show the usefulness of this technique for tracing lineaments, active faults, and terraces in South Korea.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.8 no.1
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• pp.81-86
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• 1996

Subsea pipelines have an important role in the overall tasks of offshore oil and gas production but arc exposed to various hazards with high potential risks of damage resulting in serious economic loss and impact on ocean environment. In this paper, the dynamic free span is analysed, which is one of main risk factors against the safety of subsea pipelines and the allowable length of dynamic free span which is important for the design of subsea pipelines is determined. The allowable free span length is examined by considering the relationship between vortex shedding frequency and natural frequency of pipeline free span, and the variation of the allowable length is analysed for different boundary conditions of pipe ends. The free span is regarded as a beam on elastic foundations and the boundary condition of the beam is generalized by modelling as restrained by linear and rotational spring at each end. A non-dimensionalized curve is obtained to facilitate the determination of exact allowable length of dynamic free span for subsea pipelines and is applied to the pipelines which is to be installed in the gas fields of the south of East Sea of Korea.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.11 no.1
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• pp.34-40
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• 1999

Models of beach response due to sea level rise were verified by experiments and potential shoreline retreat around Korea and Japan was predicted. Wave tank experiments demonstrated that not only static retreat by water level rise but also additional retreat by wave action plays an important role in total retreat and additional retreat becomes important on the condition of high waves. The result of long-term analysis of tidal data over past 3 decades shows the tendency toward rise by an average of 1.79 mm/year, which is the result of rise in 29 regions and fall in 12 regions. Based on analyzed rate of long-term sea-level rise, potential shoreline retreats of study area after 50 years were calculated and the result shows serious loss of beach.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.6
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• pp.70-77
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• 2004

In many industrial applications, an unexpected fault of induction motor drive systems can cause serious troubles such as downtime of the overall system heavy loss, and etc. As one of methods to solve such problems, this paper investigates the fault diagnosis for open-switch damages in a voltage-fed PWM inverter for induction motor drive. For the feature extraction of a fault we transform the current signals to the d-q axis and calculate mean current vectors. And then, for diagnosis of different fault patterns, we propose a clustering based diagnosis algorithm The proposed diagnostic technique is a modified ANFIS(Adaptive Neuro-Fuzzy Inference System) which uses a clustering method on the premise of general ANFIS's. Therefore, it has a small calculation and good performance. Finally, we implement the method for the diagnosis module of the inverter with MATLAB and show its usefulness.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2004.05b
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• pp.241-246
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• 2004

Medical images are being managed more by PACS in general medical institutions. It is important to protect patients from being invaded their privacy related to the images. It is also necessary to confirm the ownership, the right of properity of the medical images and notice whether the data are modified. In this paper, we propose a robust watermarking against RST attacks in medical images on the PACS. The proposed scheme modifies and improves Log-Polar Mapping and Fourier Mellin Transform in order to realize and recover serious image degradation and watermark data loss caused by the conversion between cartesian coordinate and log-polar coordinate. We used the radius and theta Look Up Table to solve the realization of the Fourier Mellin Transform, and inserted a watermark into 2D-DFT magnitudes using Spread Spectrum. Experimental results shows that this method are robust to several attack.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2004.05b
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• pp.804-806
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• 2004

As a noninvasive imaging meathod, optical coherence tomography system has been extensively studied because it has some advantage such as imaging of high resolution, low cost, and compace size configuration. The optical power of the sample signal reflected from an object is usually very small in optical coherence tomography(OCT) due to absorption and scattering in a sample material. Furthermore, there happens a serious loss of sample signal power in a fiber coupler because it does not transfer to a photodetector but return to the optical source. In order to improve the SNR of OCT system, basic Michelson and Mach-Zehnder interferometer types were configured then, we compared simulation with measurement of reference sample Therefore, an On in configuration of Math-Zehnder interferometer was demonstrated in order to improve the signal to noise ratio

• The Korean Journal of Applied Statistics
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• v.20 no.3
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• pp.449-458
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• 2007

Bipolar disorder, also known as manic-depressive illness, is a brain disorder that causes unusual shifts in person's mood, energy, and ability to function. Compared with manic episode, the depression episode causes more serious results such as restless, loss of interest or pleasure, or thoughts of death or suicide and the cure rate of depression episode is lower than that of manic episode. Furthermore, a long term use of antidepressants in bipolar patients may result in manic episode. Our interest is to investigate the effect of antidepressant on switch of moods of bipolar patients and to estimate the transition probabilities of switch between moods, depression and (hypo) manic. In this study, three approaches are applied in terms of multi state model. Parametric model is applied using left censoring data and nonparametric model is implemented under illness-death model with counting process. In order to estimate the effect of covariates, a multiplicative model is used. These all methods have similar results.

• Archives of Plastic Surgery
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• v.34 no.4
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• pp.436-440
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• 2007

Purpose: TRAM flap surgery has settled down as a common method for breast reconstruction after mastectomy. We investigated how TRAM flap surgery influences on the patients' physical movement capability by observing their capability of sit-ups as well as exercises they usually enjoy. Methods: A total of consecutive 375 patients were investigated who had breast reconstruction with unilateral pedicled TRAM flap surgery at Asan Medical Center from July 2001 to August 2005. The patients were asked to sit up right before the surgery and do it again 6 months later and 1 year later. 221 patients were followed up 6 month after the surgery. And 132 patients were followed up 1 year after the surgery. In addition, 155 patients who used to exercise before the surgery were also asked to show us the change in their physical movement capability one year after their surgery. Results: 139 patients showed decrease in the counted number of sit-ups, 48 increase, and 34 showed no change between 6 months in the first group of 221 patients. Among the second group of 132 patients, 64 showed decrease, 39 increase, and 29 no change a year later. There was a statistical significant decrease in the number of sit-ups between pre-operation and six months later and between pre-operation and one year later. According to the research on the exercise that 155 patients participated, 3 of them showed improvement in athletic ability, 7 showed decrease, while the rest, 145 patients, showed no change at all. Conclusion: Considering no difference in usual exercise ability, some patients' increase in the number of sit-ups and the effect of anticancer treatment, we found that the loss of abdominal wall function on this research is not too serious to exclude TRAM flap surgery in the field of breast reconstruction

• Archives of Plastic Surgery
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• v.38 no.4
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• pp.508-511
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• 2011

Purpose: Blue toe syndrome consists of blue or purplish toes in the absence of a history of obvious trauma, serious cold exposure, or disorders producing generalized cyanosis. It is a life-threatening and still underrecognized disease. It can be commonly occurred by vascular surgery, invasive cutaneous procedures or anticoagulant therapy. Our case is presented of blue toe syndrome related to atheromatous embolization that was presumably triggered by angio CT. Methods: A 69-year-old man presented with the suddenly developed pain, cyanosis and livedo reticularis of the toes in right foot. Dorsalis pedis pulses were palpable. He had been performed a diagnostic angio CT 1 month earlier. Angio CT revealed diffuse aortic atheromatous plaque in lower abdominal aorta and both common iliac artery. One month after angio CT, he visited our clinic. There was no visible distal first dorsal metatarsal artery and digital artery of right first toe in lower extremity arteriography. A diagnosis was established of blue toe syndrome. Because his symptom was aggravated, we performed the exploration of the right foot. After exposure of first dorsal metatarsal artery, microsurgical atheroembolectomy was done. Results: There were no postoperative complications. After three months the patient had no clinically demonstrable problems. Conclusion: Patient with blue toe syndrome is at high risk of limb loss and mortality despite treatment. Blue toe syndrome produces painful, cyanosed toes with preserved pedal pulses. It needs to be aware of blue toe syndrome. Careful history should reveal the diagnosis. Treatment is controversial, however, most believe that anticoagulation therapy should be avoided.

• Journal of the Korean Institute of Intelligent Systems
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• v.20 no.4
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• pp.541-547
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• 2010

Marine accidents do not correspond with another accidents because of a serious loss of lives and property. The many marine accidents can be attributed to human error like as carelessness and decision faults, and hence there is a strong need for decision-support tools for marine navigation. Much of researchers have introduced the techniques about the tools, but they hardly consider environmental factors (water depth, the width of waterway, a fishing ground, a current, the number of surrounding marine accidents, marine obstacles, etc), which are very important to the decision making of officers. In a previous research, we proposed the conceptual model of environmental risk assessment of ship navigation using fuzzy. This paper describes the detailed design of the environmental factors based on the opinion of navigation experts, and shows the validity of the conceptual model through a prototype system.