• Journal of Biomedical Engineering Research
• /
• v.43 no.3
• /
• pp.170-176
• /
• 2022

Cell separation from a heterogenous mixture sample is an essential process for downstream analysis in biological, chemical, and clinical applications. This study demonstrates an integrated hybrid device of the viscoelastic focusing in a straight rectangular channel and subsequent size-based separation using acoustophoresis to attain high efficiency and separation tunability. For particle pre-alignment in a viscoelastic fluid, the flow rate higher than 10 μl/min was required. Surface acoustic wave-based lateral migration of particles with different sizes (13 and 27 ㎛) was examined at various applied voltages and flow rate conditions. Therefore, the flow rate of 100 μl/min and the applied voltage of 20 V_pp can be used for size-based particle separation.

• Korean Journal of Environmental Agriculture
• /
• v.41 no.1
• /
• pp.32-40
• /
• 2022

BACKGROUND: Climate-smart agriculture (CSA) has been proposed for sustainable agriculture and food security in an agricultural ecosystem disturbed by climate change. However, scientific approaches to local agricultural ecosystems to realize CSA are rare. This study attempted to evaluate the weather condition, rice production, and greenhouse gas emissions from the rice cultivation in Hwaseong-si, Gyeonggi-do to fulfill CSA of the rice cultivation. METHODS AND RESULTS: Over the past 3 years (2017~2019), Chucheong rice cultivar yield and methane emissions were analyzed from the rice field plot (37°13'15"N, 127° 02'22"E) in the Gyeonggi-do Agricultural Research and Extension Services located in Gisan-dong, Hwaseong-si, Gyeonggi-do. Methane samples were collected from three automated closed chambers installed in the plot. The weather data measured through automatic weather station located in near the plot were analyzed. CONCLUSION(S): The rice productivity was found to vary with weather environment in the agricultural ecosystem. And methane emissions are high in a favorable weather condition for rice growth. Therefore, it is necessary to minimize the trade-off between the greenhouse gas emission target for climate change mitigation and productivity improvement for CSA in a local rice cultivation.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2021.06a
• /
• pp.86-86
• /
• 2021

온천천은 부산광역시 금정구, 동래구, 연제구를 흐르는 도심 하천으로 부산 시민들의 도심 속 산책길, 자전거 길 등으로 활용되는 도시하천이다. 그러나 온천천 양안의 동래 곡저 평야가 시가지화 되고 온천천 발원지인 금정산 주변에서 무허가 상수도를 사용하고 각종 쓰레기와 하수의 유입으로 인해 하천 전체가 하수관으로 변해왔다. 이에 따라 부산광역시는 온천천 정비 계획을 시행하여 하천 정비와 함께 자동측정망을 설치하여 하천의 DO (dissolved oxygen), 탁도, TDS농도 등 자료를 수집하고 있다. 그러나 자동측정망으로 쌓여가는 데이터를 활용하여 DO농도 예측은 거의 이뤄지지 않고 있다. DO는 하천의 수질 오염 정도를 판단하는 수질인자로 역사적으로 하천 연구의 주요 연구 대상이 되어 왔다. 본 연구에서는 일 자료 뿐만 아니라 시 자료를 기반으로 RNN-LSTM 알고리즘을 활용한 DO예측을 시도하였다. RNN-LSTM은 시계열 학습에 뛰어난 알고리즘으로 인공신경망의 발전된 형태인 순환신경망이다. 연구에 앞서 부산광역시 보건환경정보 공개시스템으로부터 받은 자료 중에서 교정, 보수 중, 비사용, 장비전원단절 등으로 인해 누락데이터를 2014년 1월 1일부터 2018년 12월 31일의 데이터 전수조사 후 이상데이터를 확인하여 선형 보간하여 데이터를 사용하였다. 연구에서는 Google에서 개발한 딥러닝 오픈소스 라이브러리인 텐서플로우를 활용하여 부산광역시 금정구 부곡동에 위치한 부곡교 관측소의 DO농도를 시간 또는 일 예측을 하였다. 일 예측 학습에는 2014년~ 2018년의 기상자료(기온, 상대습도, 풍속, 강수량), DO농도 자료를 사용하였고, 시 예측 학습에는 연속된 자료가 가장 많은 2015년 3월 ~ 12월까지의 데이터를 활용하여 연구를 진행하였다. 모형의 검증을 위해 결정계수(R square)를 이용하여 통계분석을 실시하였다.

• Korean Journal of Soil Science and Fertilizer
• /
• v.47 no.2
• /
• pp.107-112
• /
• 2014

Glomalin has been suggested as an enhancer for soil stability by promoting the aggregation. In this study, we examined the concentrations of glomalin and microbial characteristics in 25 controlled horticultural soils sampled from Gyeongnam Province. Total glomalin had a significant positive correlation with soil organic matter (p < 0.01), soil microbial biomass carbon (p < 0.05), and dehydrogenase activity (p < 0.05) in controlled horticultural soils. In addition, the total glomalin had a significant positive correlation with concentrations of total fatty acid methyl esters, Gram-negative and Gram-positive bacteria, fungi, and arbuscular mycorrhizal fungi in controlled horticultural soils (p < 0.001). In conclusion, the concentration of total glomalin could be an indicator of microbial biomass richness for sustainable agriculture in controlled horticultural soils.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.6 no.10
• /
• pp.2750-2763
• /
• 2012

The Domain Name System (DNS) is a critical Internet infrastructure that provides name to address mapping services. In the past decade, Denial-of-Service (DoS) attacks have targeted the DNS infrastructure and threaten to disrupt this critical service. While the flooding DoS attacks may be alleviated by the DNS caching mechanism, we show in this paper that flooding DoS attacks utilizing name error queries is capable of bypassing the cache of resolvers and thereby impose overwhelming flooding attacks on the name servers. We analyze the impacts of such DoS attacks on both name servers and resolvers, which are further illustrated by May 19 China's DNS Collapse. We also propose the detection and defense approaches for protecting DNS servers from such DoS attacks. In the proposal, the victim zones and attacking clients are detected through monitoring the number of corresponding responses maintained in the negative cache. And the attacking queries can be mitigated by the resolvers with a sample proportion adaptive to the percent of queries for the existent domain names. We assess risks of the DoS attacks by experimental results. Measurements on the request rate of DNS name server show that this kind of attacks poses a substantial threat to the current DNS service.

• Food Science of Animal Resources
• /
• v.40 no.1
• /
• pp.106-117
• /
• 2020

Cellular senescence is associated with age-related vascular disorders and has been implicated in vascular dysfunctions. Here, we show that duck oil-loaded nanoemulsion (DO-NE) attenuates premature senescence of vascular smooth muscle cells (VSMCs) triggered by angiotensin II (Ang II). Compared with control nanoemulsion (NE), DO-NE significantly inhibited the activity of senescence-associated β-galactosidase, which is a biomarker of cellular senescence, in Ang II-treated VSMCs. SIRT1 protein expression was dose- and time-dependently induced in VSMCs exposed to DO-NE, but not in those exposed to NE, and SIRT1 promoter activity was also elevated. Consistently, DO-NE also dose-dependently rescued Ang II-induced repression of SIRT1 expression, indicating that SIRT1 is linked to the anti-senescence action of DO-NE in VSMCs treated with Ang II. Furthermore, the SIRT1 agonist resveratrol potentiated the effects of DO-NE on VSMCs exposed to Ang II, whereas the SIRT1 inhibitor sirtinol elicited the opposite effect. These findings indicate that DO-NE inhibits senescence by upregulating SIRT1 and thereby impedes vascular aging triggered by Ang II.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.22 no.6
• /
• pp.1374-1377
• /
• 2008

The aim of this study is to explore the principle that the joints of the limbs belong to Five Phases in Korean medicine. According to the principle of I-Ching, Ha-Do provides the logic which could attach everything to Five Phases. Ha-Do is composed of the numbers from one through ten, and in order to explain the logic of Universe formation, it furnishes the method of transforming 'immateriality' into 'materiality'. If we apply formation theory of Ha-Do to the joints of the limbs, however, it could be understood that the trunk of body develops the appendages, which means Ha-Do suggests a logic that 'materiality' generates 'materiality' in this case. Therefore, it is not the Water but the Earth that occurs first in the appendages development in this theory, and the shoulder joints belong to the Earth. Following development should occur in order of Five Phases formation of Ha-Do ; that is to say, the elbow joints belong to the Water, the wrist joints belong to the Fire, the finger joints belong to the Wood, and the ends of fingers belong to the Metal.

• The Mathematical Education
• /
• v.44 no.4 s.111
• /
• pp.603-625
• /
• 2005

Identity is the concept which approaches individuals' affective problems with the social and cultural view. The previous studies on the problems, studied the attitudes, beliefs, or emotions while they restricted the problems to teachers or students' private problems. Otherwise, identities focus on individuals which participate to any community and share its social practices(Mclead, 1994). This study purposed to get an understanding on the teaching and learning mathematics in elementary mathematics classroom with an ethnographic view, while we consider mathematics as a kind of social practices, and mathematics classrooms as communities of practice. We analysed teacher's identities on mathematics and teaching mathematics depending on her responses of the questions as following: How does she think about mathematics, what are the instructional goals in her mathematics classroom, how do students learn mathematics in her mathematics classroom. In addition, we analysed students' identities on mathematics and learning mathematics depending on their responses of the questions as following: What do students think of mathematics, do they like mathematics, why do they study mathematics, how do they feel their mathematics classroom(describe your classroom) and themselves in it(describe yourselves in your classroom), what are their duties and what do they do actually in their mathematics classroom.

• Proceedings of the Korean Society for Bio-Environment Control Conference
• /
• 2003.04a
• /
• pp.98-103
• /
• 2003

우리나라의 가지 재배면적은 1970년 2,815ha이었던 것이 그 후 점차 줄어들어 2001년은 866ha가 재배되고 있고, 시설재배면적은 1970년 27ha로 전체면적의 1%도 채 안되는 매우 적은 면적이었으나 2001년에는 전체면적의 33%에 가까운 284ha가 재배되고 있다. 연간 총생산량으로 보면 1970년에 비하여 큰 차이가 없다. 이는 노지재배의 10a당 수량이 적을 때는 892kg 많을 때는 2,782kg 이나 시설재배의 10a당 수량은 1,617-4,294kg으로 노지재배에 비해 시설재배의 수량이 많기 때문이다(M.A.F. 2001). (중략)

• Proceedings of the Korean Society for Bio-Environment Control Conference
• /
• 2003.04a
• /
• pp.104-111
• /
• 2003

우리나라의 가지는 2001넌 866ha에서 재배하여 28.4천톤이 생산되었다(농촌진흥청. 2001). 또한 1994년부터 일본에 수출하기 시작하여 2001년에는 1,948톤에 3,541천불을 기록하고 있다. 이러한 물량은 일본 전체 유통물량 448천톤의 0.5%에 불과하여 앞으로 일본수출 물량을 늘려나갈 수 있는 여지가 많다고 할 수 있다. 그러나 일본에서 요구하는 안전하고 고품질의 가지를 저비용으로 생산하기 위해서는 시설 내에서 수경재배, 격리상 재배가 필요하다고 생각한다. (중략)