• Proceedings of the Korea Information Processing Society Conference
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• 2020.05a
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• pp.547-550
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• 2020

노인인구의 급증에 따라 노인 건강에 대한 관심이 증가하였고 노인 낙상을 발견하는 방법에 대한 관심도 함께 대두되기 시작하였다. 낙상 사고의 경우 낙상을 일으킨 원인보다 낙상이 제때 감지되지 않아 발생하는 이후의 상황이 더욱 심각한 결과를 초래한다. 따라서 낙상이 발생했을 때, 바로 낙상을 감지할 수 있는 시스템 구축이 필요하다. 다양한 낙상 검출을 위한 방법이 존재하지만 그 중 착용이 쉽고 원격지에서 관찰 및 관리가 가능한 웨어러블(Wearable) 기기의 센서 데이터를 사용한 낙상 검출을 진행하였다. 본 논문에서는 머신 러닝 모델들을 사용해서 낙상 검출 성능 비교 및 적절한 모델을 제안한다. 기계 학습 기반의 모델인 결정 트리(Decision Tree), 랜덤 포래스트(Random Forest), SVM(Support Vector Machine)을 사용하여 실제 측정된 데이터에 낙상 검출 학습 능력을 정량화하였다. 또한, 모델의 입력 값에 적용한 데이터 분할, 전처리 및 특징 추출 방법을 통해서 효율적인 낙상 검출을 위한 기계학습 관점에서의 타당성을 판단하고자 한다.

• Korean Journal of Agricultural and Forest Meteorology
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• v.5 no.3
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• pp.172-178
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• 2003

This study was conducted to assess the physiological tolerance of native tree species for successful restoration and revegetation of abandoned coal-mine spoils. Study sites were two coal-mine spoils (Sododong and Ssarijae) in Taebaek, Kangwon Province, Korea. Five individuals of Betula costata and of B. schmidtii were analyzed for malondialdehyde (MDA) and hydrogen peroxide ($H_2O$$_2$) content, nitrate reductase (NR) and superoxide dismutase (SOD) activity, and for carbohydrate concentration in the leaves. Trees in the abandoned coal-mine spoils were influenced by deficiencies expressed by MDA and $H_2O$$_2$ content in the leaves of two species being higher at the coal-mine spoils than in the surrounding forest. Low NR activity indirectly represented nitrogen deficiency in the soil of the coal-mine spoils; an unmanageable SOD activity implied that tolerant functions didn't net against a certain stress of the coal-mine spoils. Decreased glucose and increased starch concentration especially showed the inhibition of the carbohydrate metabolism by inadequate factors. Consequently, low nitrogen content in the real-mine soils might increase damage in trees as a result of inhibiting the expression of tolerance mechanisms against stress. Therefore, trees in coal-mine spoils need ample nitrogen to use as a metabolic energy source in order to prevent damage and increase tolerance against stress.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.211-213
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• 2010

본 논문에서는 형태학적 처리 방법과 8 방향 윤곽선 추적을 이용하여 손금을 추출하는 방법을 제안한다. YCbCr컬러 공간에서 Y:65~255, Cb:25~255, Cr:130~255에 해당되는 피부색 임계치를 이용하여 손 영역을 추출한다. 추출된 손 영역에서 내부 픽셀의 3:1 이상, 전체 영상의 2:1이상인 손의 형태학적 정보와 8 방향 윤곽선 추적 기법을 이용하여 잡음을 제거한다. 잡음이 제거된 손 영상에서 스트레칭 기법과 소벨 마스크를 이용하여 에지를 추출한다. 추출된 에지 영상에서 블록 이진화 기법을 이용하여 이진화한 후에 가로와 세로가 각각 10픽셀 이상이고 20픽셀 이하인 손금의 형태학적 정보를 이용하여 잡음 및 손의 윤곽선을 제외한 손금을 추출한다. 추출된 손금에서 Labeling 기법을 이용하여 개별 손금의 중요선을 추출한다. 핸드폰 카메라에서 획득한 손바닥 영상을 대상으로 실험한 결과, 제안된 방법이 손금 추출에 효율적인 것을 확인할 수 있었다.

• KIPS Transactions on Software and Data Engineering
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• v.12 no.11
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• pp.493-504
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• 2023

The Republic of Korea is located far from the boundary of the earthquake plate, and the intra-plate earthquake occurring in these areas is generally small in size and less frequent than the interplate earthquake. Nevertheless, as a result of investigating and analyzing earthquakes that occurred on the Korean Peninsula between the past two years and 1904 and earthquakes that occurred after observing recent earthquakes on the Korean Peninsula, it was found that of a magnitude of 9. In this paper, the Korean Peninsula Historical Earthquake Record (2 years to 1904) published by the National Meteorological Research Institute is used to analyze the relationship between earthquakes on the Korean Peninsula and statistical self-similarity. In addition, the problem solved through this paper was the first to investigate the relationship between earthquake data occurring on the Korean Peninsula and statistical self-similarity. As a result of measuring the degree of self-similarity of earthquakes on the Korean Peninsula using three quantitative estimation methods, the self-similarity parameter H value (0.5 < H < 1) was found to be above 0.8 on average, indicating a high degree of self-similarity. And through graph visualization, it can be easily figured out in which region earthquakes occur most often, and it is expected that it can be used in the development of a prediction system that can predict damage in the event of an earthquake in the future and minimize damage to property and people, as well as in earthquake data analysis and modeling research. Based on the findings of this study, the self-similar process is expected to help understand the patterns and statistical characteristics of seismic activities, group and classify similar seismic events, and be used for prediction of seismic activities, seismic risk assessments, and seismic engineering.

• Journal of the Microelectronics and Packaging Society
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• v.23 no.4
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• pp.57-61
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• 2016

Thick film sealing glass paste is required for cell packaging of NaS based battery for energy storage system, to join the beta-alumina electrolyte tube and the alpha-alumina battery cell cap components. This paper presents the effect of the particle sizes of seal glass powder and the sealing temperatures on the microstructure of the glass sealants was investigated. It was found that the larger in the particle size of seal glass powder, the smaller the pore volume and the number of pores in a unit area. Also, the number of pores decreased with increasing the sealing temperatures while the pore size was increased. This result enables the control of porosity, pore distribution and number of pores in a microstructure of glass sealing component by proper selection of glass powders particle size and sealing temperature.

• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.2
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• pp.219-226
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• 2020

Over the last decades, great efforts have been devoted to reuse industrial wastes and by-products from various industries as supplementary cementitious materials in order to reduce carbon dioxide(CO₂) emission by reducing the use of Portland cement in construction. Oyster shell waste, originating from the fishery industry, is available in huge quantities in certain areas, and is generally discarded or landfilled. In this study, we aimed to reuse oyster shell as an alternative to limestone in limestone calcined clay cement(LC³). The oyster shell calcined clay cement(OC³) paste were produced and were characterized via X-ray diffraction, isothermal calorimetry, compressive strength tests, and thermogravimetry. The results revealed that OC³ pastes exhibited similar strength development and reactivities by pozzolanic reaction with LC³, which implies that oyster shell could be used as a substitute for limestone in LC³.

• Knowledge Management Research
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• v.22 no.4
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• pp.119-133
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• 2021

As a large amount of data is produced in each industry, a number of time series pattern prediction studies are being conducted to make quick business decisions. However, there is a limit to predicting specific patterns in nonlinear time series data due to the uncertainty inherent in the data, and there are difficulties in making strategic decisions in corporate management. In addition, in recent decades, various studies have been conducted on data such as demand/supply and financial markets that are suitable for industrial purposes to predict time series data of irregular random walk models, but predict specific rules and achieve sustainable corporate objectives There are difficulties. In this study, the prediction results were compared and analyzed using the Chaos analysis method for roulette data and financial market data, and meaningful results were derived. And, this study confirmed that chaos analysis is useful for finding a new method in analyzing time series data. By comparing and analyzing the characteristics of roulette games with the time series of Korean stock index future, it was derived that predictive power can be improved if the trend is confirmed, and it is meaningful in determining whether nonlinear time series data with high uncertainty have a specific pattern.

• Journal of the Microelectronics and Packaging Society
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• v.25 no.4
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• pp.149-154
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• 2018

This paper describes the fabrication and heat transfer property of 50 watts rated LED array module where multiple chips are mounted on chip-on-board type ceramic-metal hybrid substrate with high heat dissipation property for high power street and anti-explosive lighting system. The high heat transfer ceramic-metal hybrid substrate was fabricated by conformal coating of thick film glass-ceramic and silver pastes to form insulation and conductor layers, using thick film screen printing method on top of the high thermal conductivity aluminum alloy heat-spreading panel, then co-fired at $515^{\circ}C$. A comparative LED array module with the same configuration using epoxy resin based FR-4 PCB with thermalvia type was also fabricated, then the thermal properties were measured with multichannel temperature sensors and thermal resistance measuring system. As a result, the thermal resistance of the ceramic-metal hybrid substrate in the $4{\times}9$ type LEDs array module exhibited about one third to the value as that of FR-4 substrate, implying that at least triple performance of heat transfer property as that of FR-4 substrate was realized.

• Journal of Applied Biological Chemistry
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• v.64 no.2
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• pp.165-170
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• 2021

In this study, the antioxidant effects of mineral-containing deep sea water (DSW) on kidney function was confirmed using a cell model. DSW samples were prepared with different mineral concentrations including calcium and magnesium-the main minerals found in DSW-to derive the following sample groups: trace minerals (TM), high magnesium (HM), high magnesium, low salt (HMLS) and high magnesium, high calcium (HMHC). The purpose of this preparation was to determine the optimal calcium/magnesium ratio in DSW. Human embryonic kidney (HEK293) cells were exposed to sodium chloride (NaCl) for 2 h to induce release of reactive oxygen species (ROS). Thereafter, the cells were treated with the respective DSW samples before ROS concentrations, as well as antioxidant enzyme activity and protein levels, were measured. Among the water samples, HMLS showed the most protective effect against ROS, whereas the intracellular glutathione content was highest in cells from the HMLS- and HMHC-treated groups. However, TM- and HMHC-treated cells showed similar tendencies to the control group, in terms of mRNA expression of antioxidant genes. These results suggested that DSW may aid in preventing renal oxidative stress caused by excessive sodium intake. Furthermore, it was determined that HMLS and HMHC water samples displayed good antioxidant effects in the kidney cell model, based on the combined results of ROS concentration and antioxidant marker measurements.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.9
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• pp.1703-1710
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• 2008

As the performance of digital camera keeps going on, the digital camera becomes into wide use recently so that the number of digital images taken by digital camera is increased rapidly. Given the augmentation of digital images, the digital photo frame has appeared for storing and enjoying the digital image and receives attention as the price of digital frame becomes down. However, users with the existing digital frame only could display the digital images and stream media stored in local disk. In the paper, we design and implement a new digital photo frame baled on ubiquitous which could provide a more variety of service to the user. With the proposed digital photo frame, the user could obtain the environment information and the digital image from multimedia sensor network. The users also could enjoy the various stream media stored in the remote streaming server seamlessly. In addition, the user could update the digital image through the web site at anywhere.