• 대한수의학회지
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• 제35권4호
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• pp.815-822
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• 1995

The toxicokinetics of rifapentine was studied after an oral administration to beagle dogs. High-performance liquid chromatography(HPLC) using column-switching technique was performed to determine the serum concentrations of rifapentine. The pharmacokinetic profiles of rifapentine were analysed using one-compartment open model. Following a single oral administration of 10mg/kg, pharmacokinetic parameters were determined as follows: maximum serum concentration($C_{max}$), $28.90{\mu}g/ml$; maximum concentration time($T_{max}$), 3.7hr; elimination half-life($t_{1/2}$, 4.7hr; area under the curve(AUC), $339.0{\mu}g{\cdot}hr/ml$; volume of disiribution/bioavailability (Vd/F), 0.21 l/kg; lag time, 24min; absorption rate constant($k_a$), $0.445hr^{-1}$; elimination rate constant($k_{el}$), $0.148hr^{-1}$. After 6 month multiple oral doses of 10mg/kg/day, parameters were as follows: $C_{max}$, $34.40{\mu}g/ml$; $T_{max}$, 2.6hr; $t_{1/2}$, 6.7hr; AUC, $391.3{\mu}g{\cdot}hr/ml$; Vd/F, 0.291/kg; $k_a$, $0.976hr^{-1}$; $k_{el}$, $0.104hr^{-1}$. The consistant kinetic parameters after a single and multiple oral administration show that there was no accumulation of rifapentine after 6 month oral administration. We also simulated the concentration of rifapentine after oral multiple administration of 10 and 50mg/kg/ day, based on the parameters obtained form the single administration. The measured serum concentrations of rifapentine were well fitted to the simulated results. The simulated results show that rifapentine readily reaches to steady-state after about 3 doses and the steady-state serum concentrations($C_{ss}$) are fluctuated in between $2.2{\sim}25.2{\mu}g/ml$, and $10.6{\sim}125.2{\mu}g/ml$ at the doses of 10 and 50mg/kg/day, respectively.

• KDI Journal of Economic Policy
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• 제36권2호
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• pp.103-136
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• 2014

무위험 이자율 평형은 환율과 금리 간의 관계를 체계적으로 설명한 조건식으로서 개방거시분석 등에 널리 활용되고 있다. 그럼에도 불구하고 동 조건 성립 여부에 대한 검증은 국가별 거시경제 여건 등의 상이성 등으로 인해 뚜렷한 합의를 이루지 못하고 있다. 특히 글로벌 금융위기 전후 주요국의 정책대응은 국제금융시장에 큰 변화를 가져왔으며, 한국을 포함한 신흥국 시장에도 간접적으로 영향을 미쳤다. 이러한 관점에서 본고는 글로벌 금융위기 전후 우리나라 무위험 이자율 평형조건의 동태성을 국면전환모형으로 모델링하고 베이지안 MCMC 방식에 기반하여 추정한 다음, 추정 결과를 바탕으로 정책적 시사점을 제시하였다. 추정 결과, 세 개의 구조변화를 가정한 모형이 우리나라 이자율 평형조건의 동태성을 가장 잘 성명하는 것으로 나타났으며, 최근에는 평형조건의 불균형 정도가 크게 완화되고 변동성도 안정적인 상태에 진입한 것으로 분석되었다. 본고는 이러한 추정 결과를 얻은 주된 이유가 글로벌 유동성 증가에 따른 외국인 채권 차익거래와 단기 원화 및 외화 자금시장의 연계성 강화에 주로 기인한 것으로 판단하였다. 추정방식 측면에서 본고는 모형 내에 구조 변화를 가정하지 않는 기존 연구를 한층 더 정교하게 발전시켰다는 점에서 기존 연구와 차별화될 뿐만 아니라 추정 결과를 해석하는 과정에서 단기 원화 및 외화 자금시장의 성격 변화에 주목하였다는 점에서 기존에 시도하지 않은 무척 새로운 접근방식이라고 할 수 있을 것이다. 본고의 정책적 시사점은 이자율 평형조건의 동태성 등을 고려하여 정책당국이 시장모니터링을 더욱 강화하고 새로운 정책수단을 발굴할 필요가 있다는 점 등이다.

• 대한의용생체공학회:의공학회지
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• 제29권2호
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• pp.99-106
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• 2008

To improve $B_1$ homogeneity in high field MRI, the RF power is applied to the transmit array coil elements sequentially in the time-multiplexed way. Since only a single coil element is activated in a time-multiplexing slot, the global standing wave formation in the human body is greatly suppressed. The time-multiplexing slot width is on the order of micro seconds, hence, high-order-harmonic slices can be placed far from the transmit coil and simultaneous multiple slice selection can be avoided. The $B_1$ homogeneities of a birdcage coil and an eight-channel transmit array coil have been compared through finite difference time domain simulations. The simulation results indicate that the proposed technique can reduce the peak-to-peak $B_1$ inhomogeneity down to one fourth of the transmission with a birdcage coil on the central plane of the human head model at 3 T. The mimicking experiments at 3 T, eight separate experiments with a single coil element activated and image reconstruction by combining the eight images, also show promising results. It is expected that the proposed technique has some advantages over other $B_1$ improving methods in real practice since simple RF switching circuitries are only necessary and electromagnetic coupling between the coil elements is out of concern in its realization.

• Journal of Communications and Networks
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• 제10권2호
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• pp.137-147
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• 2008

This paper proposes a novel approach to interference avoidance via inter-cell relaying in cellular OFDMA-TDD (orthogonal frequency division multiple access - time division duplex) systems. The proposed scheme, termed asymmetry balancing, is targeted towards next-generation cellular wireless systems which are envisaged to have ad hoc and multi-hop capabilities. Asymmetry balancing resolves the detrimental base station (BS)-to-BS interference problem inherent to TDD networks by synchronizing the TDD switching points (SPs) across cells. In order to maintain the flexibility of TDD in serving the asymmetry demands of individual cells, inter-cell relaying is employed. Mobile stations (MSs) in a cell which has a shortage of uplink (UL) resources and spare downlink (DL) resources use free DL resources to off-load UL traffic to cooperating MSs in a neighboring cell using ad hoc communication. In an analogous fashion DL traffic can be balanced. The purpose of this paper is to introduce the asymmetry balancing concept by considering a seven-cell cluster and a single overloaded cell in the center. A mathematical model is developed to quantify the envisaged gains in using asymmetry balancing and is verified via Monte Carlo simulations. It is demonstrated that asymmetry balancing offers great flexibility in UL-DL resource allocation. In addition, results show that a spectral efficiency improvement of more than 100% can be obtained with respect to a case where the TDD SPs are adapted to the cell-specific demands.

• 한국음향학회지
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• 제15권5호
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• pp.73-81
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• 1996

많은 수의 프로세서와 메모리 소자사이의 연결을 위한 구조들은 다단 상호연결 네트워크를 이용해서 구현할 수 있다. 또한 경제성, 처리능력 및 고장 허용면에서의 발전은 자연스럽게 컴퓨터 시스템 성장에 있어서 가장 중요한 요건이 되었다. 그러나 지금까지의 다단 상호연결 네트워크에서의 고장의 허용방법, 특히 전단에 관한 연구가 미흡하다. 따라서 본 논문에서는 기존의 다단 상호연결 네트워크중에서 generalized cube네트워크를 바탕으로 링크 고착 고장 및 direct와 cross상태에서 스위칭 소자의 고장, 그리고 새로운 broadcast상태에서 고장진단을 포함하는 generalized cube네트워크에 스위칭 소자가 가지는 4가지 상태의 전체적인 진단을 한다. 가정된 고장모델을 검출할 수 있는 테스트 집합을 산출하고 이를 통해서 고장의 검출 및 위치를 결정할 수 있는 효율적인 알고리즘을 제안하고 적용의 예를 보인다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.13-13
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• 2010

Switching an elementary excitation by injecting a single carrier would offer the exciting opportunity for the ultra-high data storage technologies. However, there has been no methodology available to investigate the interaction of low energy discrete carriers with nano-structures. In order to map out the spatial dependency of such single carrier level interactions, we developed a pulse-and-probe algorithm, combining with low temperature scanning tunneling microscopy. The new tool, which we call single carrier spectroscopy, allows us to track the interaction with the target macrostructure with tunneling carriers on a single carrier basis. Using this tool, we demonstrate that it is possible not only to locally write and erase individual bi-solitons, reliably and reversibly, but also to track of creation yields of single and multiple bi-solitons. Bi-solitons are pairs of solitons that are elementary out-of-phase excitations on anti-ferromagnetically ordered pseudo-spin system of Si dimers on Si(001)-c(42) surfaces. We found that at low energy tunneling the single bisoliton creation mechanism is not correlated with the number of carriers tunneling, but with the production of a potential hole under the tip. An electric field at the surface determines the density of the local charge density under the tip, and band-bending. However a rapid, dynamic change of a field produces a potential hole that can be filled by energetic carriers, and the amount of energy released during filling process is responsible for the creation of bi-solitons. Our model based on the field-induced local hole gives excellent explanation for bi-soliton yield behaviors. Scanning tunneling spectroscopy data supports the existence of such a potential hole. The mechanism also explains the site-dependency of bi-soliton yields, which is highest at the trough, not on the dimer rows. Our study demonstrates that we can manipulate not just single atoms and molecules, but also single pseudo-spin excitations as well.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권6호
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• pp.1892-1912
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• 2022

With the massive demand and growth of cloud computing, virtualization plays an important role in providing services to end-users efficiently. However, with the increase in services over Cloud Computing, it is becoming more challenging to manage and run multiple Virtual Machines (VMs) in Cloud Computing because of excessive power consumption. It is thus important to overcome these challenges by adopting an efficient technique to manage and monitor the status of VMs in a cloud environment. Reduction of power/energy consumption can be done by managing VMs more effectively in the datacenters of the cloud environment by switching between the active and inactive states of a VM. As a result, energy consumption reduces carbon emissions, leading to green cloud computing. The proposed Efficient Dynamic VM Scheduling approach minimizes Service Level Agreement (SLA) violations and manages VM migration by lowering the energy consumption effectively along with the balanced load. In the proposed work, VM Scheduling for Efficient Dynamically Migrated VM (VMS-EDMVM) approach first detects the over-utilized host using the Modified Weighted Linear Regression (MWLR) algorithm and along with the dynamic utilization model for an underutilized host. Maximum Power Reduction and Reduced Time (MPRRT) approach has been developed for the VM selection followed by a two-phase Best-Fit CPU, BW (BFCB) VM Scheduling mechanism which is simulated in CloudSim based on the adaptive utilization threshold base. The proposed work achieved a Power consumption of 108.45 kWh, and the total SLA violation was 0.1%. The VM migration count was reduced to 2,202 times, revealing better performance as compared to other methods mentioned in this paper.

• 한국자기학회지
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• 제16권2호
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• pp.130-135
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• 2006

강자성체/비자성 금속/강자성체/반도체 구조에서 층간교환강호작용(interlayer exchange coupling) 에너지가 외부 인가전압으로 제어 가능함을 이론적으로 보였다. 비자성 금속층으로 격리된 두 강자성층 사이의 층간교환상호작용 에너지는 강자성체/비자성 금속 계면에서 전자의 스핀에 의존하는 반사율의 차이에 의해 결정된다는 것은 잘 알려진 사실인데, 이를 각자성체/비자성 금속/강자성체/반도체 구조에 적용하여 층간교환상호작용 에너지가 강자성체/비자성 금속/강자성체 계면에서 전자의 반사율뿐 아니라 강자성체/반도체 계면에서의 반사율에도 의존한다는 것을 보였다 강자성체/반도체 계면에 생기는 Schottky 장벽의 높이와 두께는 인가전압으로 바꿀 수 있고, 그에 따른 전자의 반사율이 인가전압에 의해 바뀔 수 있음을 알 수 있었다. 결과적으로 일차원 자유전자 모델을 사용하여 외부 인가 전압으로써 두 강자성체 사이의 층간 교환 상호작용 에너지를 제어할 수 있다는 것을 확인하였다.