• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2021.11a
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• pp.139-141
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• 2021

In the maritime digital forensic part, it is very important and difficult process that analysis of data and information with vessel navigation system's binary log data for situation awareness of maritime accident. In recent years, anaysis of vessel's navigation system's trajectory information is an essential element of maritime accident investigation for vessel digital forensic process. So, we analysis of maritime navigation systems of vessel and feature of device and environments. In the future, we will research on information of ship's trajectory and movement for useful forensic service.

• Journal of Advanced Marine Engineering and Technology
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• v.31 no.8
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• pp.990-997
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• 2007

In the last 5 years, collisions of fishing vessels have recorded about 54.6% of the total marine accidents. Specially about 64.0% of these collisions were caused by navigator's negligence of watch keeping during works. The purpose of this paper is to develop vessel detecting system that is able to receive the whistle blast of other vessel and make a warning sound and light when the fishermen can not confirm the approaching another vessel on account of fishing works. It is designed to receive the whistle signal blast by a weather tight microphone. The signal is processed by analog active filter in order to enhance the SNR(Signal to noise ratio). And this microprocessor-based system is programmed to do ADC(Analog to digital converting), FFT analysis, controls of warning sound and light.

• Journal of Digital Convergence
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• v.12 no.4
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• pp.349-356
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• 2014

This research is aimed to prove if harmful effects of smoking, as the main reason for recently elevated blood vessel disease, could be reduced by aerobic exercise, and identify the positive effects of the aerobic exercise on smokers' blood vessel health(blood pressure, pulse pressure, and blood vessel elasticity. Experiments were performed on 40 male smokers aged between 40 and 55, which was equally divided into two groups of Aerobic Exercise Group (AEG) and Non Exercise Group (NEG). After measuring each group's blood pressure, pulse pressure, and blood vessel elasticity, AEG practiced aerobic exercise program for 50 minutes for each trial, three times a week, sustaining 12 weeks while NEG continued daily-life patterns without any special treatment. In 12 weeks, blood pressure, pulse pressure, and blood vessel elasticity of both groups were measured as the same way. As a result, the difference of systolic blood pressure between the two groups was not significant, while that of diastolic blood pressure was meaningful. The difference of pulse pressure between the two groups was meaningful, and that of blood vessel elasticity was also meaningful in all measuring points including left hand, right hand, left foot and right foot. As a consequent, it was found that aerobic exercise had positive effects on middle aged male smokers' blood vessel health.

• Korean Journal of Child Studies
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• v.35 no.4
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• pp.17-40
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• 2014

The aims of this study were three-fold; to analyze the trends of research on children's media, to anticipate any transitions in the direction of the research and finally to provide a guidance for future directions in the research. For this purpose, 55 research papers were chosen. The tool used for this analysis was that developed by Meyrowitz(1998; 1999), which classifies(1998, 1999) three main viewpoints towards media. Based on these three viewpoints, this study found that the most common category is 'media as a vessel.' Furthermore, it was verified that some studies in 'media as a vessel' have a tendency to be mixed with the notion of 'media as a language.' Subsequently, all the research papers in the category of 'media as a language' were subcategorized into 6 digital literacy competencies, in the manner proposed by Hobbs(2010). Consequently, the studies in the category of 'creation' were revealed to be the most common, and it was further confirmed that the research included in the categories of 'reflection' and 'social action' both begins to partially appear. Based on these results, this study speculates on a number of educational points supporting the development of media education in the digital era.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.321-325
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• 2004

Retinopathy of Prematurity (ROP) is a common retinal neovascular disorder of premature infants. It can be characterized by inappropriate and disorganized vessel. This paper present a method for blood vessel detection on infant retinal images. The algorithm is designed to detect the retinal vessels. The proposed method applies a Lapalacian of Gaussian as a step-edge detector based on the second-order directional derivative to identify locations of the edge of vessels with zero crossings. The procedure allows parameters computation in a fixed number of operations independent of kernel size. This method is composed of four steps : grayscale conversion, edge detection based on LOG, noise removal by adaptive Wiener filter & median filter, and Otsu's global thresholding. The algorithm has been tested on twenty infant retinal images. In cooperation with the Digital Imaging Research Centre, Kingston University, London and Department of Opthalmology, Imperial College London who supplied all the images used in this project. The algorithm has done well to detect small thin vessels, which are of interest in clinical practice.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.05
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• pp.414-417
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• 1997

This paper presents vessel contour for extracting features and segmentating narrow blood vessels down to a diameter of two pixels in digital subtraction angiographic image. We present a new tracking algorithm for contour, mainly blood vessels in DSA image, and extracting properties such as their intensities, diameters, and center lines by exploiting spatial continuity. The proposed algorithm comes to detect blood vessel's boundary using difference edge detector one of homogeneity operator and find a next centerline position by direction vector of edge information. This algorithm enhanced variation of vessel's diameter compared to Sun's tracking algorithm and lessoned to compute as direction vector decide adaptively entire vessel's direction field. The processed images are intended to support radiologists in diagnosis, radiation therapy planning, and surgical planning. The algorithm should be useful for automating angiographic analyses of blood vessels.

• Journal of Digital Convergence
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• v.15 no.1
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• pp.267-275
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• 2017

The purpose of this study was to evaluate the clinical availability of ankle-brachial index(ABI) according to severity of cardiovascular disease. The subjects of this study were the patients who had ABI in a general hospital. In this study, total 441 patients were enrolled for analysis. Electric medical records were reviewed to investigate the result of ABI and severity of cardiovascular disease measured vessel disease and Gensini score. Collected data were analyzed using SPSS 21.0 program. Subjects with $ABI{\leq}0.90$ and > 0.90 were classified as having abnormal and normal ABI. There were significant differences in vessel disease categorization($x^2=4.731$, p=.030) and Gensini score(t=2.351, p=.019) between two groups. Therefore, ABI is an effective and non-invasive tool for the diagnosis of cardiovascular disease with high severity. ABI is a valuable predictive index of ischemic heart disease.

• The Journal of Korea Robotics Society
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• v.5 no.4
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• pp.309-317
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• 2010

This paper proposes an efficient measurement system for the velocity and direction of the wind using the dual rotor wind power generator in vessel. Conventional digital measurement system recognizes the direction and the velocity of the wind using the electric compass or synchronous motor and Vane probe method using hall sensors. But each system has its own short-comings: the synchronous motor has a larger measurement error than the magnetic compass and magnetic compass is weak for the external disturbances such as fluctuation of the vessel. To compensate these short-comings, this paper proposes a new compensation algorithm for the fluctuation errors according to the external interference and the unexpected movement of the vessel along the roll and pitch directions. The proposed system is implemented with the dual compasses and a synchronous motor. The proposed independent power generation system can be operated by itself and can raise the efficiency of the wind power generation systems of 30 ~ 400 W installed along the vertical and horizontal axes. The proposed system also realizes the efficient and reliable power production system by the MPPT algorithm for the real-time recognition of the wind direction and velocity. An advanced switching algorithm for the battery charging system has been also proposed. Effectiveness of the proposed algorithm has been verified through the real experiments and the results are demonstrated.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.6
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• pp.796-802
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• 2018

The effects of inner liquid sloshing on vessel motions are a well-known factor. It was investigated experimentally and numerically. In this regard, the study of many efforts to reduce natural phenomena of vessel motions by adopting special devices especially for roll motions. Among many devices, inserting baffles in the inner liquid tank is very common. In this study, one investigated the vessel motions with inner sloshing tanks with baffles inside. For the numerical simulation, one employed a dynamically coupled program between boundary-element-method-based vessel motion analysis program and a particle-based computational fluid dynamics program. Comparing corresponding experimental results validated the dynamically coupled program. The validated coupled program was used to simulate vessel motions, including sloshing effects with various lengths of inner baffles. The simulation results show that not only the filling ratio of inner liquid, but also the length of clearance due to baffles influenced the vessel motions. The significant point of this study was that the natural frequency of vessel motions can be maintained irrespective of the amount of filling ratio through adjustment of the clearance. In a future study, the effects of various numbers of baffles with various clearances would be conducted to percuss the possibility of vessel motion control with inner liquid sloshing effects.

• Journal of the Korean Institute of Telematics and Electronics
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• v.22 no.3
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• pp.48-53
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• 1985

A real time digital subtraction angiographic system (RTDSA) was developed and utilized for diagnosis of the diseases related with the blood vessel conditions in 200 patients. In this paper, we present the system configurations and the real time processed images of the patients'abdominal, renal, femoral, and hepatic arteries.