• Title, Summary, Keyword: VF model

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Study of equivalent circuit modeling for microstrip structure using passive component (수동소자를 이용한 마이크로스트립 구조의 등가회로 모델링에 관한 연구)

  • Paek, Hyun;Kim, Kun-Tae;Kwon, So-Hyun;Kahng, Sung-Tek;Kim, Hyeong-Seok
    • Proceedings of the KIEE Conference
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    • pp.1434-1435
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    • 2008
  • In this paper, we propose a method that applies Vector Fitting(VF) and Adaptive Frequency Sampling(ASF) technique to the equivalent circuit model for RF passive components. VF and ASF schemes are implemented to obtain the rational functions. S parameters of the equivalent circuit model is compared to those of EM simulation in case of the microstrip structure with coupled bandpass filter.

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A Measurement Error Correction Algorithm of Road Image for Traveling Vehicle's Fluctuation Using V.F. Modeling (V.F. 모델링을 이용한 주행차량의 진동에 대한 도로영상의 계측오차 보정 알고리듬)

  • Kim Tae-Hyo;Seo Kyung-Ho
    • Journal of Institute of Control, Robotics and Systems
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    • v.12 no.8
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    • pp.824-833
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    • 2006
  • In this paper, the image modelling of road's lane markings is established using view frustum(VF) model. From this model, a measurement system of lane markings and obstacles is proposed. The system also involve the real time processing of the 3D position coordinate and the distance data from the camera to the points on the 3D world coordinate by virtue of the camera calibration. In order to reduce their measurement error, an useful algorithm for which analyze the geometric variations due to traveling vehicle's fluctuation using VF model is proposed. In experiments, without correction, for instance, the $0.4^{\circ}$ of pitching rotation gives the error of $0.4{\sim}0.6m$ at the distance of 10m, but the more far distance cause exponentially the more error. We con finned that this algorithm can be reduced less than 0.1m of error at the same condition.

The Electrophysiological Effects of Benzopyran Potassium Channel Openers on Coronary Artery Occlusion/Reperfusion-induced Arrhythmias in the Rat (흰쥐에서의 관상동맥 결찰/재관류로 유도된 부정맥에 대한 benzopyran계 $K^+$ channel opener의 전기생리학적인 효과)

  • Lee, Jae Heung;Shin, Hwa Sup;Kwon, Kwang Il
    • Korean Journal of Clinical Pharmacy
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    • v.6 no.2
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    • pp.32-40
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    • 1996
  • The electrophysiological effects of benzopyran potassium channel openers (PCOs: lemakalim, KR-30450 and KR-30818) on the ischemia/reperfusion-induced arrythmias were investigated. In anesthetized rats, subjected to 45 min occlusion of the left anterior descending coronary artery (LAD) followed by 90 min reperfusion, ventricular arrythmias were identified according to the Lambeth Conventions by lead II ECG. Rats were intravenously given vehicle ($1\%$ DMSO), lemakalim, KR-30450, and KR-30818 alone or in combination with a selective $K_{ATP}$ blocker glibenclamide, 30 min prior to coronary occlusion. Compared to vehicle, lemakalim ($30{\mu}g/kg$ i.v.), the active enantiomer of cromakalim, had a tendancy to increase the duration of ventricular tachycardia (Vl) and ventricular fibrillation (VF), the number of premature ventricular complexes (PVC) and the incidence of VF, especially in the early post-occlusion peroid ($0\~15$ min), while increasing ST-segment elevation. Both KR-30450 ($30{\mu}g/kg$, i.v.) and KR-30818 (30, $100{\mu}g/kg$, i.v.) showed similar proarrhythmic effects to lemakalim (PVC, duration of VT, and incidence of VF) with a tendancy to decrease the duration of VF and ST-segment elevation. Unlike other PCOs, however, glibenclamide (0.3, 1.0 mg/kg) had opposite effects on the induction of arrhythmias (PVC, the duration of VF); it had a tendancy to increase the duration of VT with a slight elevation of ST-segment. It seems likely that glibenclamide (0.3 mg/kg, i.v.), reduced the effects of lemakalim or KR-30450 ($30{\mu}g/kg$, i.v.) on arrhythmias (PVC, VT, VF and ST-segment). These results indicate that, in the coronary occluded rat model of ischemia, lemikuiln and KR-30450 exert a proarrhythmic activity, the effect being considered related to the opening of KATP channel.

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A Measurement Error Correction Algorithm of Road Structure for Traveling Vehicle's Fluctuation Using VF Modeling (VF 모델링을 이용한 주행차량의 진동에 대한 도로 계측오차 보정 알고리듬)

  • Jeong, Yong-Bae;Kim, Jung-Hyun;Seo, Kyung-Ho;Kim, Tae-Hyo
    • Proceedings of the Korea Institute of Convergence Signal Processing
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    • pp.190-200
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    • 2005
  • In this paper, the image modelling of road's lane markings is established using view frustum(VF) modeling. This algorithm also involve the real time processing of the 3D position coordinate and the distance data from the camera to the points on the 3D world coordinate by the camera calibration. In order to reduce their measurement error, an useful algorithm for which analyze the geometric variations clue to traveling vehicle's fluctuation using VF model is proposed. In experiments, without correction, for instance, the $0.4^{\circ}$ of pitching rotation gives the error of $0.4^{\sim}0.6m$ at the distance of 10m, but the more far distance cause exponentially the more error. We confirmed that this algorithm can be reduced less than 0.1m of error at the same condition.

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Gradual Reperfusion Lowers the Incidence of Reperfusion-Induced Ventricular Fibrillation in a Cat Model of Regional Ischemia

  • Kim, You-Ho;Na, Heung-Sik;Nam, Hyun-Jung;Hur, Gyu-Young;Lee, Seung-Whan;Park, Sung-Sook;Hong, Seung-Kil
    • The Korean Journal of Physiology and Pharmacology
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    • v.3 no.1
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    • pp.47-52
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    • 1999
  • Blood flow restoration to ischemic zone of the heart is essential to salvage of ischemic tissue. However, there is a large body of evidence documenting that the reperfusion can induce reperfusion injury like reperfusion-induced malignant arrhythmias. In the present study, employing a cat model of regional cardiac ischemia, we examined if reperfusion rendered in a gradual fashion could lower the incidence of reperfusion-induced ventricular fibrillation (VF), which usually precipitated within a few to several tens of seconds after abrupt reperfusion. The experiments were conducted with male mongrel cats (n=46, 2.5-5 kg). The animals in the control and 30 MIN groups were subjected to an episode of 20- and 30-min left anterior descending coronary artery occlusion, respectively, followed by abrupt reperfusion. The animals in 5 G and 10 G groups received gradual reperfusion over a 5- and 10-min period, respectively, following a 20-min occlusion. The proportion of animals that exhibited VF during the reperfusion phase was 11/15 in the control, 7/10 in the 30 MIN, 5/10 in the 5 G and 2/11 in the 10 G groups. The incidence of VF in the 10 G group was significantly lower than that in the control or 30 MIN group subjected to abrupt reperfusion. These results suggest that the gradual reperfusion is a useful procedure against reperfusion-induced VF.

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Equivalent Circuit Modeling Applying Rational Function Fitting (유리함수 근사를 이용한 등가회로 모델링)

  • Paek, Hyun;Ko, Jae-Hyung;Kim, Kun-Tae;Kim, Hyeong-Seok
    • Journal of The Institute of Information and Telecommunication Facilities Engineering
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    • v.8 no.1
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    • pp.1-5
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    • 2009
  • In this paper, we propose a method that applies Vector Fitting (VF) technique to the equivalent circuit model for RF passive components. These days wireless communication system is getting smaller and smaller. So EMI/EMC is an issue in RF. We can solve PI/SI (Power Integrity/Signal Integrity) that one of EMI/EMC problem apply IFFT for 3D EM simulation multiple with input signal. That is time consuming task. Therefore equivalent circuit model using RF passive component is important. VF schemes are implemented to obtain the rational functions. S parameters of the equivalent circuit model is compared to those of EM simulation in case of the microstrip line structure.

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Development of a Semi-automatic Search Program for Crown Delineation Based on Watershed and Valley Following Algorithms

  • Sim, Woodam;Park, Jeongmook;Lee, Jungsoo
    • Journal of Forest and Environmental Science
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    • v.34 no.2
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    • pp.142-144
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    • 2018
  • This paper discusses the development of semi-automatic search program for crown delineation in stand level. The crown of an individual tree was delineated by applying the Watershed (WS) and Valley Following (VF) algorithms. Unmanned Aerial Vehicle (UAV) images were used in the semi-automatic search program to delineate the crown area. The overall accuracy and Khat were used in accuracy assessment. WS algorithm's model showed the overall accuracy and Khat index of 0.80 and 0.59, respectively, in Plot 1. However, the overall accuracy and Khat of VF algorithm's model were 0.78 and 0.51, respectively, in Plot 2.

CFD analysis of ventilation efficiency around an elevated highway using visitation frequency and purging flow rate

  • Huang, Hong;Kato, Shinsuke;Ooka, Ryozo;Jiang, Taifeng
    • Wind and Structures
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    • v.9 no.4
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    • pp.297-313
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    • 2006
  • The concentration of air pollution along roads is higher than the surrounding area because ventilation efficiency has decreased due to the high-density use of space along roads in recent years. In this study, ventilation efficiency around a heavily traffic road covered by an elevated highway and hemmed in along its side by buildings is evaluated using Visitation Frequency (VF, the frequency for pollutant to return to the objective domain) and Purging Flow Rate (PFR, the air flow rate for defining the local domain-averaged concentration). These are analyzed using Computational Fluid Dynamics (CFD) based on the standard $k-{\varepsilon}$ model. The VF and PFR characteristics of four objective domains are analyzed in terms of the changes in wind direction and arrangements of the fencing dividing up and down direction in the road center under the elevated highway. The resulting VFs are more than 1.0 for all cases, which means that pollutants return to the objective domain restricted by the elevated highway and side buildings. The influence of the arrangement of the buildings around the objective domain and the structure in the domain on the VF is substantial. In cases where there are no obstacles under the elevated highway, the local air exchange rate in the domain tends to be improved. Using these indices, the urban ventilation efficiencies between different urban areas can be compared easily.

Effect of Valeriana fauriei Extract on the Neurodevelopmental Proteins Expression and Behavioral Patterns in Maternal Immune Activation Animal Model (쥐오줌풀 추출물이 MIA동물모델에서의 신경발달 단백질의 발현과 행동증상에 미치는 영향)

  • Won, Hansol;Kim, Young Ock;Lee, Hwayoung;Im, Jiyun;Lee, Sanghyun;Cho, Ik Hyun;Lee, Sang Won;Park, Chun Geun;Kim, Hyung Ki;Kwon, Jun Tack;Kim, Hak Jae
    • Korean Journal of Medicinal Crop Science
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    • v.24 no.5
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    • pp.341-350
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    • 2016
  • Background: Prenatal exposure to infectious and/or inflammatory insults can increase the risk of developing neuropsychiatric disorder such as bipolar disorder, autism, and schizophrenia later in life. We investigated whether Valeriana fauriei (VF) treatment alleviates prepulse inhibition (PPI) deficits and social interaction impairment induced by maternal immune activation (MIA). Methods and Results: Pregnant mice were exposed to polyriboinosinic-polyribocytidilic acid (5 mg/kg, viral infection mimic) on gestational day 9. The adolescent offspring received daily oral treatment with VF (100 mg/kg) and injections of clozapine (5 mg/kg) for 30 days starting on the postnatal day 35. The effects of VF extract treatment on behavioral activity impairment and protein expression were investigated using the PPI analysis, forced swim test (FST), open field test (OFT), social interaction test (SIT), and immunohistochemistry. The MIA-induced offspring showed deficits in the PPI, FST, OFT, and SIT compared to their non MIA-induced counterparts. Treatment with the VF extract significantly recovered the sensorimotor gating deficits and partially recovered the aggressive behavior observed in the SIT. The VF extract also reversed the downregulation of protein expression induced by MIA in the medial prefrontal cortex. Conclusions: Our results provide initial evidence of the fact that the VF extract could reverse MIA-induced behavioral impairment and prevent neurodevelopmental disorders such as schizophrenia.

An optimization approach for the optimal control model of human lower extremity musculoskeletal system (최적화 기법에 의한 인체 하지 근골격 시스템의 최적제어 모델 개발)

  • Kim, Seon-Pil
    • Journal of the Korea Industrial Information Systems Research
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    • v.10 no.4
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    • pp.54-64
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    • 2005
  • The study investigated genetic algorithms for the optimal control model of maximum height vertical jumping. The model includes forward dynamic simulations by the neural excitation-control variables. Convergence of genetic algorithms is very slow. In this paper the micro genetic algorithm(micro-GA) was used to reduce the computation time. Then a near optimal solution from micro-GA was an initial solution for VF02, which is one of well-developed and proven nonlinear programming algorithms. This approach provided the successful optimal solution for maximum-height jumping without a reasonable initial guess.

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