• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.8
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• pp.1820-1831
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• 2011

When both types of periodic and aperiodic tasks are required to run on a sensor node platform with limited energy resources, we propose an energy-efficient hybrid task scheduling technique that guarantees the deadlines of real-time tasks and provides non-real-time tasks with good average response time. The proposed hybrid task scheduling technique achieved better performance than existing EDF-based DVS scheduling techniques available in the literature, the FIFO-based TinyOS scheduling technique, and the task-clustering based non-preemptive real-time scheduling technique.

• Proceedings of the Korean Information Science Society Conference
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• 2006.06a
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• pp.73-75
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• 2006

생물체 내에서 중요 생물학적 기능을 수행하는 기본 단위인 단백질 및 이들의 상호작용 대한 많은 연구가 이루어져 다양한 생물체에 대한 단백질 상호작용 데이터베이스가 구축되었다. 본 논문에서는 효모에 대해 공개되어있는 단백질 상호작용 데이터를 이용하여 새로운 단백질 상호작용을 예측하는 방법을 제안한다. 논문에서는 문헌에서 연관 정보를 효율적으로 찾아내기 위하여 제안된 연관개념공간 탐색 방법을 확장하여 단백질 상호작용 예측에 사용한다. 단백질들은 각각이 가지는 다양한 속성들의 벡터로 간주되며, 상호작용은 해당 단백질들의 연관성을 통해 이루어지는 것으로 표현된다. 상호작용하는 두 단백질들의 속성은 단어의 공동 출현과 같이 고려되어 단백질 상호작용은 두 단백질 벡터의 요소로 표현되고 벡터의 요소 속성들 간의 연관성을 표현하기 위해 연관속성개념공간으로 사상되어 공간상의 거리 기반으로 연관속성을 추출한다. 추출된 연관속성을 최대로 포함하는 단백질들 간의 상호작용을 예측하는 방식으로 단백질 상호작용을 예측한다. 논문에서 제안한 방법은 효모의 단백질 상호작용 예측에 대해 평균 약 91.8%의 예측 정확도를 보여, 연관속성개념공간을 이용한 방법이 단백질 상호작용을 예측하는 또 다른 대안으로 사용 될 수 있음을 확인하였다.

• Korean Journal of Food Science and Technology
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• v.22 no.3
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• pp.300-306
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• 1990

The microstrutural changes of mayonnaise during storage were examined by light microscopy (LM) and scanning electron microscopy (SEM). Fresh mayonnaise was composed of heterogenous population of dispersed spherical oil droplets and droplet size was normally distributed with one mode. During storage at $60^{\circ}C\;and\;-10^{\circ}C$, a shift in droplet size distribution toward larger droplets was observed, as a result of coalescence of lipid droplets. Turbidimetric study also confirmed that coalescence was occurring during this accelerated aging treatments. Measurements obtained from SEM microgrphs provided better determination of smaller droplets and resulted in lower mean diameter of droplets than those obtained from LM. From these results, SEM was found to be an advantageous method of examining emulsion products as compared to LM, providing a better resolution of small droplets and a more representative view of droplet distribution, as dilution of the sample was avoided.

• Korean Chemical Engineering Research
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• v.49 no.4
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• pp.411-416
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• 2011

NCO terminated polyurethane prepolymers were synthesized from isophorone diisocyanate(IPDI), polycarbonate diol(PCD) and dimethylol propionic acid(DMPA). Subsequently, acrylic terminated prepolymers were prepared by capping the NCO groups of polyurethane prepolymers with different moles of pentaerythritol triacrylate (0~0.024 moles) as a acrylate monomer. The average particle size of the acrylic terminated polyurethane solutions was increased with increasing PETA contents. Also, the prepared coating films showed better abrasion resistance and pencil hardness than pure waterborne polyurethane.

• Proceedings of the Korean Information Science Society Conference
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• 2006.06b
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• pp.232-234
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• 2006

본 논문에서는 마르코프 결정 문제 (Markov decision problem)의 풀이 효율을 잴 수 있는 척도를 알아보기 위해 복잡계 네트워크 (complex network) 의 관점에서 MDP를 하나의 그래프로 나타내고, 그 그래프의 위상학적 성질들을 여러 네트워크 척도 (network measurements)들을 이용하여 측정하고 그 MDP의 풀이 효율과의 관계를 분석하였다. 실세계의 여러 문제들이 MDP로 표현될 수 있고, 모델이 알려진 경우에는 평가치 반복(value iteration)이나 모델이 알려지지 않은 경우에도 강화 학습(reinforcement learning) 알고리즘등을 사용하여 풀 수 있으나, 이들 알고리즘들은 시간 복잡도가 높아 크기가 큰 실세계 문제에 적용하기 쉽지 않다. 이 문제를 해결하기 위해 제안된 것이 MDP를 계층적으로 분할하거나, 여러 단계를 묶어서 수행하는 등의 시간적 추상화(temporal abstraction) 방법들이다. 시간적 추상화를 도입할 경우 MDP가 보다 효율적으로 풀리는 꼴로 바뀐다는 사실에 착안하여, MDP의 풀이 효율을 네트워크 척도를 이용하여 측정할 수 있는 여러 위상학적 성질들을 기반으로 분석하였다. 다양한 구조와 파라미터를 가진 MDP들을 사용해 네트워크 척도들과 MDP의 풀이 효율간의 관계를 분석해 본 결과, 네트워크 척도들 중 평균 측지 거리 (mean geodesic distance) 가 그 MDP의 풀이 효율을 결정하는 가장 중요한 기준이라는 사실을 알 수 있었다.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07b
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• pp.277-279
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• 2005

단백질들은 서로 다른 단백질들과 상호작용하거나 복합물을 형성함으로써 생물학적으로 중요한 기능을 한다고 알려져 있다. 때문에 대부분의 세포작용에 있어 중요한 역할을 하는 단백질들 간의 상호작용 분석 및 예측에 대한 연구는 여러 연구그룹으로부터 풍부한 데이터가 산출된 후게놈시대(post-genomic era)에서 또 하나의 중요한 이슈가 되고 있다. 본 논문에서는 효모에 대해 공개되어있는 단백질 상호작용 데이터들에서 속성들 간의 연관규칙 학습을 통해 잠재적 단백질 상호작용들을 예측하기 위한 연관규칙 기반의 상호작용 예측 방법을 제시한다. 단백질들 간의 상호작용 예측을 위해 고려되는 각 단백질의 다수의 속성차원은 정보이론 기반의 속성선택 알고리즘을 이용하여 효율적으로 줄이며 상호작용의 속성집합을 이용하여 신경망을 훈련시키고 이렇게 훈련된 신경망에서 속성들 간의 연관규칙을 디코딩하여 연관규칙 기반의 상호작용 예측에 활용한다. 연관속성 발굴을 통한 상호작용 예측을 위한 마이닝 방법으로는 연관규칙 발견 알고리즘을 사용하였으며 예측 정확도를 높이기 위하여 신경망 예측 모델의 학습 결과를 디코딩한 규칙들이 추가적으로 사용하였다. 논문에서 제안한 방법을 발견된 연관규칙을 통한 단백질 상호작용 예측문제에 있어 평균 약 $94.5\%$의 예측 정확도를 보였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2018.10a
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• pp.866-868
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• 2018

본 연구는 표면 근전도를 이용하여 서로 다른 손가락 움직임을 분류하여 일상 생활 속 다양한 사물(e.g, TV, 에어컨 등)을 제어하는 시스템을 개발을 목표로 한다. 손등에 총 4 개의 양극성 전극을 사용하여 피험자 5명으로부터 표면 근전도를 측정하였다. 각 피험자는 검지, 중지, 약지, 소지를 구부리는 동작 및 휴직 상태에 다섯 가지 다른 과제를 각각 3초씩 50회 수행하였으며, 이 때 표면 근전도를 피험자의 손등에서 측정하였다. 측정한 근전도 신호의 분산을 특징으로 추출하여 선형 판별 분석을 적용한 결과 평균 $81.3{\pm}6.3%$의 분류 정확도를 얻을 수 있었다. 추후 분류 정확도 향상을 위한 추가 연구를 통해 시스템의 신뢰도를 더욱 향상시키고 실제 사물을 제어하는 시스템을 개발하고자 한다.

• Korean Journal of Ecology and Environment
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• v.36 no.3 s.104
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• pp.356-368
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• 2003

Water quality of effluent from wastewater treatment plants (WWTPS) was reviewed to examine the feasibility of agricultural reuse using USEPA and WHO guidelines. It might meet the guidelines for BOD and SS, however, the most critical microbiological concentration was too high and further treatment is required. The pilot study of three treatments were performed to reduce microbiological concentrations. The UV irradiation was proved to be very effective in disinfection of secondary level effluent, and about 30 mW ${\cdot}$ s/$cm^2$ of dose was suggested to meet the even most stringent USEPA guidelines. Slow sand filter demonstrated effective removal of bacteria, and effluent concentration of total coliform (TC), fecal coliform (FC), and E. coli. dropped from about 10,000/100 mL to 300, 200, and 150 MPN/100 mL, respectively, showing over 95% removal. These level of bacterial concentration sufficiently meet the WHO guidelines ($10^3\;{\sim}\;10^5$ FC/100 mL), and could meet the more stringent USEPA guidelines (200 FC/100 mL) if properly applied. Slow sand filter also provided about 50% removal of SS, turbidity, and BOD in addition to bacterial removal. The removal efficiency of pond system was relatively poor, but still showed over 85% removal and effluent concentration of TC, FC, and E. coli was all below 10,000/100 mL. The pond system alone could meet the WHO guidelines, but hardly meet the USEPA guidelines and further treatment might be necessary. Overall, three methods evaluated in the study treat the effluent to meet the WHO microbiological guidelines for agricultural reuse. The UV disinfection and slow sand filter might also could the USEPA guidelines, while the pond system can hardly meet the USEPA guidelines if applied alone. The WHO and USEPA guidelines were made based on data from upland field agricultural system and may not be directly applicable to the paddy field agricultural system. Therefore, national standards for agricultural reuse of reclaimed water should be made considering domestic agricultural systems as well as international guidelines. Also, further investigation is recommended to develop optimum and feasible treatment measures for agricultural reuse of effluent from WWTPs.

• Korean Journal of Ecology and Environment
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• v.39 no.2 s.116
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• pp.167-177
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• 2006

Both fish community and water quality in Lake Doam were investigated from September 2004 to August 2005. The turbidity of Lake Doam located in the upper region of the Songchun River in the South River system, Korea was high whole year due to the effects of distributed non point source pollutions in the watersheds. During the experimental periods, mean concentration of chlorophyll-a in epilimnetic layer (0 ${\sim}$ 5 m) was 18.5 ${\mu}g\;L^{-1}$ and transparency ranged from 0.3 m to 2.4 m. Average TP and TN concentrations were 111 ${\mu}g\;L^{-1}$ and 4.1 $mg\;L^{-1}$, respectively. Lake was classified as eutrophic state based on the nutrient concentrations suggested by U.S.EPA (1976). Total number of fish collected in Lake Doam was 9,600 individuals in 26 species of 6 family. Both dominant and subdominant species in the lake were P. herzi (34.9%) and Z. platypus (22.5%), respectively. Occurrence of water column species was high at upper region of the lake, whereas benthic type of species highly ,appeared in downstream area. The different fish assemblage between upper and lower area would be considered as the difference of bottom substrate and concentrations of suspended solids. In addition high appearance of Comat type of fish that is hybrid between gold fish (C, auratus) and C. auratus was found in the lake. It was unclear the reasons that high proportion of mutant species appeared in the lake. More researches are required in this area in future.

• Journal of the Korean Orthopaedic Association
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• v.55 no.1
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• pp.62-70
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• 2020

Purpose: External tibia torsion and proximal tibial vara have been reported in severe varus deformed osteoarthritis, which is a tibio-femoral angle of more than 20°. The radiology measurements were compared with those of control group and the preoperative and follow-up radiology and clinical results were examined. Materials and Methods: From January 2007 to March 2016, 43 knees from 37 persons, who underwent total knee arthroplasty for a severe varus deformity of more than 20° on the tibio-femoral angle on the standing radiographs and had a follow-up period more than two years, were examined. The mean follow-up period was 45.7 months. The control group, who underwent conservative treatments, had Kellgren-Lawrence grade three osteoarthritis and a tibio-femoral angle of less than 3° varus. The external tibial torsion of enrolled patients and control group were estimated using the proximal tibio-fibular overlap length and the tibial torsion values on computed tomography. The proximal tibia vara was measured using the proximal tibial tilt angle. The preoperative and postoperative proximal tibio-fibular overlap length, tibial torsion value, proximal tibial tilt angle, and hospital for special surgery (HSS) score were evaluated. Results: The mean proximal tibio-fibular overlap length was 18.6 mm preoperatively and 11.2 mm (p=0.031) at the follow-up. The control group had a mean proximal tibio-fibular overlap length of 8.7 mm (p=0.024). The mean tibial torsion value was 13.8° preoperatively and 14.0° (p=0.489) at the follow-up. The control group had a mean tibial torsion value of 21.9° (p=0.012). The mean proximal tibial tilt angle was 12.2° preoperatively and 0° (p<0.01) at the follow-up. The control group had a mean proximal tilt angle of 1.2° (p<0.01). The preoperative tibiofemoral angle and mechanical axis deviation were corrected from preoperative 28.3° and medial 68.4 mm to postoperative 0.7° and medial 3.5 mm (p<0.01, p<0.01), respectively. The HSS scores increased from 34 points of preoperatively to 87 points at the last follow-up (p=0.028). Conclusion: Patients with advanced osteoarthritis with a severe varus deformity of more than 20° had significant increases in the external tibial torsion and varus of the proximal tibia. The tibial torsion value before and after surgery in the enrolled patients was not changed statistically, but good clinical results without complications were obtained.