• Title/Summary/Keyword: Virginia Tech

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Development of PCR based approach to detect potential mosaicism in porcine embryos

  • Cho, Jongki;Uh, Kyungjun;Ryu, Junghyun;Fang, Xun;Bang, Seonggyu;Lee, Kiho
    • Journal of Animal Reproduction and Biotechnology
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    • v.35 no.4
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    • pp.323-328
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    • 2020
  • Direct injection of genome editing tools such as CRISPR/Cas9 system into developing embryos has been widely used to generate genetically engineered pigs. The approach allows us to produce pigs carrying targeted modifications at high efficiency without having to apply somatic cell nuclear transfer. However, the targeted modifications during embryogenesis often result in mosaicism, which causes issues in phenotyping founder animals and establishing a group of pigs carrying intended modifications. This study was aimed to establish a genomic PCR and sequencing system of a single blastomere in the four-cell embryos to detect potential mosaicism. We performed genomic PCR in four individual blastomeres from four-cell embryos. We successfully amplified target genomic region from single blastomeres of 4-cell stage embryo by PCR. Sanger sequencing of the PCR amplicons obtained from the blastomeres suggested that PCR-based genotyping of single blastomere was a feasible method to determine mutation type generated by genome editing technology such as CRISPR/Cas9 in early stage embryos. In conclusion, we successfully genotyped single blastomeres in a single 4-cell stage embryo to detect potential mosaicism in porcine embryos. Our approach offers a simple platform that can be used to screen the prevalence of mosaicism from designed CRISPR/Cas9 systems.

Load Disturbance Compensation for Stand-alone Inverters Using an Inductor Current Observer

  • Choe, Jung-Muk;Moon, Seungryul;Byen, Byeng-Joo;Lai, Jih-Sheng;Lim, Young-Bae;Choe, Gyu-Ha
    • Journal of Power Electronics
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    • v.17 no.2
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    • pp.389-397
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    • 2017
  • A control scheme for stand-alone inverters that utilizes an inductor current observer (ICO) is proposed. The proposed method measures disturbance load currents using a current sensor and it estimates the inductor current using the ICO. The filter parameter mismatch effect is analyzed to confirm the ICO's controllability. The ICO and controllers are designed in a continuous-time domain and transferred to a discrete-time domain with a digital delay. Experimental results demonstrate the effectiveness of the ICO using a 5-kVA single-phase stand-alone inverter prototype. The experimental results demonstrate that the observed current matches the actual current and that the proposed method can archive a less than 2.4% total harmonic distortion (THD) sinusoidal output waveform under nonlinear load conditions.

GREENING ENGINEERING AND CONSTRUCTION EDUCATION: STRATEGIC ENTRY POINTS FOR SUSTAINABILITY IN EXISTING CURRICULA

  • Annie R. Pearce;Yong Han Ahn
    • International conference on construction engineering and project management
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    • 2009.05a
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    • pp.764-773
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    • 2009
  • This paper presents an overview of six strategic entry points for sustainability in the context of the construction/engineering curriculum. It compares the pedagogical costs and benefits of each approach and shares lessons learned from experiences at two leading public American universities: Georgia Institute of Technology and Virginia Polytechnic Institute. The paper discusses opportunities in terms of two perspectives on the pedagogy of sustainability: Stealthy Sustainability and Flagrant Sustainability, as part of a strategy of diffusion and routinization of this innovation within existing curricula. The paper concludes with a discussion of considerations that should be taken into account when evaluating the potential for sustainability in new educational contexts.

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Predicting Runoff and Sediment Yield on a Forest Dominated Watershed using HSPF and SWAT Models (HSPF와 SWAT 모형을 이용한 산림유역의 유출 및 유사량 추정)

  • Im Sang-Jun;Brannan Kevin M.;Mostaghimi Saied;Cho, Jae-Pil
    • Journal of Korean Society of Rural Planning
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    • v.9 no.4 s.21
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    • pp.59-64
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    • 2003
  • U.S. EPA의 BASINS (Better Assessment Science Integrating Point and Nonpoint Sources)에 통합되어 있는 HSPF (Hydrologic Simulation Program-Fortran)와 SWAT (Soil and Water Assessment Tool) 모형을 이용하여 Polecat Creek 유역의 유출과 유사량을 모의하였다. 모형의 보정을 위하여 1996년 9월부터 2000년 6월까지의 하천 유량 및 유사 농도 자료를 이용하였으며, 1994년 10월부터 1995년 12월까지의 관측자료를 이용하여 모형의 검정을 실시하였다. HSPF 모형에 의해 추정된 연 평균 유출량의 상대오차는 보정 및 검정기간에 각각 0.8%, 0.5%이었으며, S WAT 모형에 의해 추정된 연평균 유출량은 실측치와 각각 2.1%, 16.1%의 오차를 보였다. 연 평균 유사량을 비교하면, HSPF 모형이 보정 및 검정기 간에 각각 8.8%와 7.2%의 오차를 보인 반면에 SWAT 모형은 각각 40.0%, 188.4%의 차이를 보였다. HSPF 모형에 의해 추정된 월 평균 유출량 및 유사량의 상관계수는 보정기간에 대하여 0.94와 0.52이었으며, SWAT 모형에 의한 결과는 상관계수가 각각 0.84와 0.39이었다. 이상의 연구 결과에 의하면, HSPF 모형이 SWAT 모형보다 유출과 유사량을 관측치와 유사하게 모의함을 알 수 있었다. 하지만 입력 자료의 구축 및 모형의 적용에는 SWAT모형보다 많은 시간과 노력을 필요로 하였다.

Seniors Perception on Age-Friendly Aspects in Jeju Island, South Korea - Urban vs Rural - (제주도 거주 노인의 고령친화도시에 관한 인식 조사 - 도시 vs 농촌 -)

  • Hwang, Eunju;Lee, Seo-yeon;Koh, Seung-Hahn;Brossoie, Nancy;Beamish, Julia
    • Journal of the Korean housing association
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    • v.26 no.5
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    • pp.37-44
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    • 2015
  • The purpose of this study was to compare urban and rural seniors' perceptions on the eight aspects of the World Health Organization Age-Friendly Cities (AFC) initiative on Jeju Island, South Korea. Face-to-face interviews using structured questionnaires were administered to 497 persons aged 65+ living on Jeju Island. Findings suggested that urban and rural held significantly different perceptions on five aspects of AFC (outdoor space and buildings, housing, civic participation and employment, community support and health services, and respect and social inclusion). Predictors of overall AFC score for all participants included age and living in a single-family home. Among urban dwellers, monthly household income and length of residence predicted AFC score while among rural seniors, predictors of AFC included educational attainment. To make communities more age-friendly, perspectives of older residents should be sought, shared, and reflected in policy and different strategies and priorities should be developed specific to urban and rural areas.

An AI-Based Prevention Program to Protect Youth from Cybergrooming

  • Kee Jeong Kim;Lifu Huang;Jin-Hee Cho
    • Journal of Internet Computing and Services
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    • v.24 no.5
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    • pp.67-73
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    • 2023
  • The Digital Age calls for improvement of information literacy particularly among children and youth who are vulnerable to cybergrooming. Taking an interdisciplinary approach by leveraging our team's expertise including child and adolescent development, data analytics, and cybersecurity, this study proposes an interactive artificial intelligence (AI)-based preventive simulation program that raises youth knowledge and awareness about the risk of cybergrooming as well as increases resilient self-efficacy in their cybersecurity-relevant skills. The primary purpose of this project is to evaluate the effectiveness of the simulation program on preventing cybergrooming. More specifically, this study is designed to examine developmental changes in self-efficacy of cybersecurity-relevant skills among youth participants as a function of the preventive simulation program. Further, this study will identify risk and protective factors that explain interindividual differences in the ability of children and youth either to fall victim to advances from a cyber predator or to recognize and deter such threats. The preliminary data will help improve the effectiveness of the preventive simulation program as well as the methods of implementation to large groups of youth. The findings from the proposed study will contribute to making specific recommendations to parents, educators, practitioners, and policy makers for the prevention of cybergrooming.

CALIBRATION AND VALIDATION OF THE HSPF MODEL ON AN URBANIZING WATERSHED IN VIRGINIA, USA

  • Im, Sang-Jun;Brannan, Kevin-M.;Mostaghimi, Saied
    • Water Engineering Research
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    • v.4 no.3
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    • pp.141-154
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    • 2003
  • Nonpoint source pollutants from agriculture are identified as one of the main causes of water quality degradation in the United States. The Hydrological Simulation Program-Fortran (HSPF) was used to simulate runoff, nitrogen, and sediment loads from an urbanizing watershed; the Polecat Creek watershed located in Virginia. Model parameters related to hydrology and water quality were calibrated and validated using observed hydrologic and water quality data collected at the watershed outlet and at several sub-watershed outlets. A comparison of measured and simulated monthly runoff at the outlet of the watershed resulted in a correlation coefficient of 0.94 for the calibration period and 0.74 for the validation period. The annual observed and simulated sediment loads for the calibration period were 220.9 kg/ha and 201.5 kg/ha, respectively. The differences for annual nitrate nitrogen ($NO_3$) loads between the observed and simulated values at the outlet of the watershed were 5.1% and 42.1% for the calibration and validation periods, respectively. The corresponding values for total Kjeldahl nitrogen (TKN) were 60.9% and 40.7%, respectively. Based on the simulation results, the calibrated HSPF input parameters were considered to adequately represent the Polecat Creek watershed.

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