• Proceedings of the KIEE Conference
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• 2002.07d
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• pp.2758-2760
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• 2002

패턴 인식(Patterns Recognition)은 인공 지능의 한 분야로서 이해할 수 있는데, 요즈음은 보안과 관련하여 많은 연구가 진행되고 있다. 웨이블렛 변환(Wavelet Transform)은 푸리에 변환에 기반을 둔 기존의 알고리즘에 비해 시간-주파수 영역에서 신호의 국소화를 효율적으로 구현할 수 있다. 하지만, 이를 패턴 인식의 특징 추출에 그대로 이용할 경우 입력 신호의 위치 이동 등이 문제가 되며, 이것은 또한 에러 요인이 된다. 본 연구에서는 웨이블렛 변환을 패턴 인식에 적용할 경우, 입력 신호의 위치 이동 등이 있는 경우 생기는 문제점을 보완하여, 개선된 방법으로 패턴 인식에 사용할 수 있는 알고리즘을 제안하며, 실험 결과를 토대로 그의 타당성을 보인다.

• Radiation Oncology Journal
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• v.21 no.2
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• pp.112-117
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• 2003

Purpose: The effects of hypefractionation radiation therapy, such as the failure pattern and survival, on the treatment results in advanced stage head and neck cancer were studied. Materials and Methods: Between September 1990 and October 1998, 24 patients with advanced stage (III, IV) head and neck cancers, were treated using hyperfractionation radiation therapy in the Department of Radiation Oncology at the Keimyung University Dongsan Medical Center. The male to female ratio was 7 : 1, and the age range from 38 to 71 years with the median of 56 years. With regard to the TNM stage, 11 patients were stage III and 13 were stage IV. The sites of primary cancer were the nasopharynx in six, the hypopharynx in 6, the larynx in five, the oropharynx in three, the maxillary sinus in three, and the oral cavity in one patient. The radiotherapy was delivered by 6 MV X-ray, with a fraction size of 1.2 Gy at two fractions a day, with at least 6 hours inter-fractional interval. The mean total radiation doses was 72 Gy, (ranging from 64.4 to 75.8 Gy). Follow-up periods ranged between 3 and 136 months, with the median of 52 months. Results: The overall survival rates at 3 and 5 years in all patients were 66.7$\%$, and 52.4$\%$. The disease-free survival rates at 3 and S years (3YDFS, 5YDFS) in all patients were 66.7$\%$ and 47.6$\%$. The 3YDFS and 5YDFS in stage III patients were 81.8$\%$ and 63.6$\%$, and those in stage IV patients were 53.8$\%$ and 32.3$\%$. Ten patients were alive with no local nor distant failures at the time of analyses. Six patients (25$\%$) died due to distant metastasis and 12.5$\%$ died due to local failure. Distant metastasis was the major cause of failure, but 2 patients died due to unknown failures and 3 of other diseases. The distant metastasis sites were the lung (3 patients), the bone (1 patient), and the liver (2 patients). One patient died of second esophageal cancer. There were no severe late complications, with the exception of 1 osteo-radionecrosis of the mandible 58 months after treatment. Conclusion: Although this study was peformed on small patients group, we considered hypefractionated radiation therapy for the treatment of advanced stage head and neck cancer might improve the disease free survival and decrease the local failure with no increase in late complications despite of the slight Increase in acute complications.

• Journal of Chest Surgery
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• v.30 no.6
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• pp.566-572
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• 1997

A major obstacles to evaluation of newly-developed treatment strategy for human lung cancer has been the lack of appropriate experimental animal models. We describe a new experimental model of orthotopically-developed non-small cell lung cancer in nude rat, involving inoculation of tumor cell suspension by thoracotomy. Over 40 direct implantation to the periphery of the lung has been performed to date, each requiring less than'1 hour for completion. This model has been used to perform a series of experiments to investigate whether the rat lung and surrounding structures trapped tumor cells with 2 different non-small cell lung cancer cell lines(NCI-H46O and NCI-H1299). Every animal showed development of tumor masses, which were loculated at the periphery of the lung karenchyma and identified also by radiography. After 3 weetu of the inoculation, tumor develop meat at the mediastinal strutures were identified. The life expectancies of the victims were different between the cell lines, but were approximately 5 weeks when NCI-H46O cell line was used. This new orthotopic lung cancer model may be facilitate future studies of the new therapeutics of localized non-small cell lung cancer .

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.10a
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• pp.323-325
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• 2022

In this paper, after administration of Chlorin e6 to kill cervical cancer cells, PDT (photodynamic therapy) using laser or LED was studied for Ce6 concentration and apoptosis by administration time. After photostimulation was applied to cervical cancer cells, qualitative and quantitative evaluation through imaging and quantitative evaluation using CCK-8 were performed. As a result of the experiment, as the concentration of Ce6 increased, a large amount of cells were killed, and it was confirmed that the Ce6+PDT test group killed more. When comparing the LED and the laser, the laser was able to kill cells only at a local location, and the LED showed the result that it was possible to kill the cells in a wide range. In addition, when irradiating a local location, such as a laser, when measuring the cell viability, it is judged to be accurate to image processing the location.

• Journal of Digital Convergence
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• v.15 no.5
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• pp.225-233
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• 2017

In this paper, we collected the articles related to artificial intelligence among SCI(E) journals published by Korean authors in 'Web of Science' and conducted frequency analysis and keyword network analysis. As a result of the analysis, the artificial intelligence thesis showed an average growth of about 10% per year, but the relative ratio decreased. As time went on, we could confirm that there is a lot of practical and applied research in artificial intelligence research. Unlike the US 'National Strategy for Artificial Intelligence Research and Development,' the field of research in Korea was focused on local and technical aspects. Therefore, Korea should go beyond the theoretical and technical iterations of artificial intelligence, and research should be carried out to present a comprehensive future direction.

• Journal of the Korean Geotechnical Society
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• v.32 no.8
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• pp.5-14
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• 2016

The leakage of water under sewer pipelines is one of main sources of sinkholes in urban areas. We performed laboratory model tests to investigate the presence of cavities using impact-echo method, which is a nondestructive test method. To simulate a concrete sewer pipe, a thin concrete plate was built and placed over container filled with sand. The cavity was modeled as an extruded polystyrene foam box. Two sets of tests were performed, one over sand and the other on cavity. A new impact device was developed to apply a consistent high frequency impact load on the concrete plate, thereby increasing the reliability of the test procedure. The frequency and transient characteristics of the measured reflected waveforms were analyzed via fast Fourier transform and short time Fourier spectrum. It was shown that the shapes of Fourier spectra are very similar to one another, and therefore cannot be used to predict the presence of cavity. A new index, termed resonance duration, is defined to record the time of vibration exceeding a prescribed intensity. The results showed that the resonance duration is a more effective parameter for predicting the presence of a cavity. A value of the resonance period was proposed to estimate the presence of cavity. Further studies using various soil types and field tests are warranted to validate the proposed approach.

• Journal of the Korean Magnetics Society
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• v.17 no.1
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• pp.26-29
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• 2007

Fe-based powders, Fe-M(M=Cr, Mn, Cu, Zn), were prepared in Ar gas by mechanical alloying and their crystallographic and magnetic properties were investigated. X-ray diffraction indicates that the cubic lattice parameter increases for the M substitution. The distance of closest approach around M can explained the increase of lattice constant in Fe-M powders. $M\"{o}ssbauer$ spectroscopy measurements on Fe-M samples indicates the coexistence of ferromagnetic phases and paramagnetic phase that are created by the distribution of local environment M on Fe atom. On the other hand, The spread of line-width on $M\"{o}ssbauer$ spectra can be explained by the distribution of hyperfine magnetic fields. The results of quadrupole shift and isomer shift revealed that M substitutions in Fe-M powders didn't change both structure and the local charge distribution around Fe atom severely.

• Journal of the Society of Naval Architects of Korea
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• v.54 no.2
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• pp.83-89
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• 2017

Numerical simulations of ship resistance have been performed to compare spatial characteristics of Courant number when using structured and unstructured meshes. When Euler scheme was used for time integration, the structured mesh provided a more efficient calculation because the calculation time interval was larger than that of unstructured mesh. The automatic generation of very small meshes in the unstructured mesh was mainly responsible for the limitation of calculation time interval. When local time stepping Euler scheme was applied, however, the ship resistance of unstructured mesh showed a rapid convergence while a slow convergence of ship resistance in structured mesh was caused by the small time interval in bulbous bow.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.121-121
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• 2021

기후변화의 영향으로 국내의 강우량과 강우패턴의 변화가 나타나고 있다. 최근 30년 여름철 집중호우의 평균강수량은 1980년 694.5 mm에서 2000년대 768.7 mm로 평균강수량이 74.2 mm 증가하였다. 평균강수일수는 36일에서 40일로 약 4일 증가하였다. 집중호우의 증가로 국소적 홍수에 의한 재해규모가 증가하고 있는 실정이다. 토양침식은 물의 순환과정에서 있어 나타나는 하나의 현상으로 토양손실을 의미한다. 강우량과 지형 및 토양특성이 토양침식량을 결정하는 주요한 요인이다. 토양침식은 농경지 감소, 고탁수 하천유입, 하천 및 호소내 퇴적으로 인한 수생태환경 변화 등의 다양한 문제를 발생시키고 있다. 그동안 우리나라는 토양침식량을 예측하기 위해 연평균 토양침식예측모형을 적용하고 있으며, 최근에 강우강도를 고려한 토양침식모형에 관한 연구가 진행되고 있다. 본 연구는 동일한 강우량을 Huff 방법을 이용하여 24시간 강수량 자료를 만들고 물리적기반 토양침식모형에 적용하여 나타나는 토양침식과 퇴적 공간분포에 대하여 분석하고자 한다.

• Journal of the Korean Society for Nondestructive Testing
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• v.36 no.5
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• pp.370-376
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• 2016

Corrosion on the surface of a structure can generate cracks or cause walls to thin. This can lead to fracturing, which can eventually lead to fatalities and property loss. In an effort to prevent this, laser imaging technology has been used over the last ten years to detect thin-plate structure, or relatively thin piping. The most common laser imaging was used to develop a new technology for inspecting and imaging a desired area in order to scan various structures for thin-plate structure and thin piping. However, this method builds images by measuring waves reflected from defects, and subsequently has a considerable time delay of a few milliseconds at each scanning point. In addition, the complexity of the system is high, due to additional required components, such as laser-focusing parts. This paper proposes a laser imaging method with an increased scanning speed, based on excitation and the measurement of standing waves in structures. The wavenumber of standing waves changes at sections with a geometrical discontinuity, such as thickness. Therefore, it is possible to detect defects in a structure by generating standing waves with a single frequency and scanning the waves at each point by with the laser scanning system. The proposed technique is demonstrated on a wall-thinned plate with a linear thickness variation.