• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2002년도 봄 학술발표논문집 Vol.29 No.1 (A)
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• pp.301-303
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• 2002

요즘 사무 빌딩이나 공항에서의 ISM(Industrial Scientific and Medical) 밴드 사용이 증가함에 따라 동일 주파수 대역을 사용하는 BT(Bluetooth)와 무선 랜은 상호 충돌 발생이 일어난다. 이러만 문제점이 최근 연구과 제로 등장하고 있다. 본 논문은 채널 간섭의 모델에 의거하는 UL(unlicensed) ISM 주파수 대역에서 BT와 802.11에 있어서 충돌 평가 모델에 의한 간섭을 분석 한다. 전파 평가 모델 방법론에 의한 AP와 STA간의 범위에 따른 BT 간섭 의 수와 허용할 수 있는 최대 BT 신호를 알아본다. 그리고, BT를 바탕으로 한 액세스 네트워의 실행에서 802.l1b 시스템에 관한 BT의 기본 간섭 메커리즘 및 간섭이 어느 정도 미치는지에 관한 예비 결과를 나타낸다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 춘계학술대회논문집
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• pp.991-996
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• 2001

It is well known that there are two experimental errors on acoustic decay measurements. One is due to the influence of the band pass filter the other one is that of an averaging device. In this paper the influence of the filter is in detail investigated. To minimize the influence of filter, the product of the filter bandwidth Β (3㏈ bandwidth) and the reverberation time T$\sub$60/ of the room under test is at least 16. Moreover, if the initial part of an acoustic decay curve is important, the strong requirement, i.e. BT$\sub$60/＞ 64, must be satisfied. In this paper, the wavelet filter bank instead of the band pass filter bank is applied to obtain an acoustic decay curve. As results, the influence of filter is reduced and then the value of BT$\sub$60/ required for obtaining an acceptable decay curve is at least 4. The strong requirement for the initial part of a decay curve is also replaced by the BT$\sub$60/＞ 16 instead of BT$\sub$60/＞ 64.

• International Journal of Industrial Entomology and Biomaterials
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• 제14권1호
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• pp.33-36
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• 2007

To improve insecticidal activity of B. thuringiensis 2385-1 (Bt 2385-1), a recombinant plasmid, pHT1K-1Ac, was introduced into lepidopteran toxic Bt 2385-1 by electroporation. The presence of the recombinant plasmid in Bt 2385-1 after electroporation was confirmed by PCR. Bt 2385-1 transformant was named as Bt pHT1K-1Ac/2385-1 (1K-1Ac/2385-1). The 1K-1Ac/2385-1 transformant produced bipyramidal-shaped parasporal inclusion as like the wild-type strain, Bt 2385-1, and showed an 130 kDa band of Cry1Ac protein. The insecticidal activity of 1K-lAc/2385-1 against S. exigua was similar to that of Bt 2385-1 but the $LC_{50}$ value of transformant against P. xylostella was 1.8 times lower. Through these bioassay results, it was confirmed that toxicity of Bt 2385-1 transformant showed synergistic effect by introducing Cry1Ac. These results suggested that the multiple expressions of Cry proteins in a promising Bt strain may interact synergistically in insect midgut, resulting in increase of toxicity and expansion of host spectrum.

• 한국전기전자재료학회논문지
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• 제16권3호
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• pp.181-185
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• 2003

Influence of post gate oxidation anneal on Negative Bias Temperature Instability (NBTI) of PMOSFE has been investigated. At oxidation anneal temperature raised above 950$^{\circ}$C, a significant improvement of NBTI was observed which enables to reduce PMO V$\_$th/ shift occurred during a Bias Temperature (BT) stress. The high temperature anneal appears to suppress charge generations inside the gate oxide and near the silicon oxide interface during the BT stress. By measuring band-to-band tunneling currents and subthreshold slopes, reduction of oxide trapped charges and interface states at the high temperature oxidation anneal was confirmed.

• 한국음향학회지
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• 제20권5호
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• pp.5-13
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• 2001

본 논문에서는 음 감쇠 측정에서 실험 오차발생의 원인 중하나인 대역 통과 필터의‘ringing’에 대하여 조사하였다. 이는 모든 감쇠 측정의 근본적인 제한으로서 이러한 필터의 영향을 줄이기 위해서는 필터의 대역폭B (3dB bandwidth)와 시스템의 잔향시간 T/sub 60/의 곱이 최소 16이상이 되어야 한다 그리고 감쇠 곡선의 초기부분이 필요한 경우에는 필요 조건이 64 이상으로 더욱 증가한다. 이에 비하여 웨이블렛 필터를 사용하는 경우 이러한 제한은 4 이상으로 완화되고 초기 부분의 사용 또한 16이상으로 조건이 크게 완화된다. 그러므로 웨이블렛 필터를 사용하여 음 감쇠 신호를 측정할 경우 저주파수 영역에서 짧은 잔향시간의 음 감쇠 신호에 대하여 더욱 정확한 측정이 가능하다.

• 한국소음진동공학회논문집
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• 제14권2호
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• pp.111-118
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• 2004

A number of researchers have attempted to measure the reverberation time of a passenger car, ut the reverberation time of passenger car is too short to measure with the traditional band pass filter. And if the reverberation time is very short, the product of the reverberation time (T) and the bandwidth (B) of the traditional band pass fitter becomes small. The low limit of BT product required for the measurement of reverberation time with the traditional band pass filter is 16. In order to overcome this problem, the wavelet filter bank was developed. In this study, this new wavelet filter was employed to measure the reverberation times of five different classes of passenger cars. The low limit of BT product required for the measurement of reverberation time with the wavelet filter is 4. The reverberation times of five passenger cars were measured successfully with the new wavelet filter bank. The reverberation times measured in most passenger cars was found to be around 0.04. Compared with general acoustic rooms like concert halls, this is a very short reverberation time

• ETRI Journal
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• 제38권4호
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• pp.634-644
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• 2016

Channel-based radio-frequency fingerprinting such as a channel impulse response (CIR), channel transfer function (CTF), and frequency coherence function (FCF) have been recently proposed to improve the accuracy at the physical layer; however, their empirical performance, advantages, and limitations have not been well reported. This paper provides a comprehensive empirical performance evaluation of RF location fingerprinting, focusing on a comparison of received-signal strength, CIR-, CTF-, and FCF-based fingerprinting using the weighted k-nearest neighbor pattern recognition technique. Frequency domain channel measurements in the IEEE 802.11 band taken on a university campus were used to evaluate the accuracy of the fingerprinting types and their robustness to human-induced motion perturbations of the channel. The localization performance was analyzed, and the results are described using the spatial and temporal radio propagation characteristics. In particular, we introduce the coherence region to explain the spatial properties and investigate the impact of the Doppler spread in time-varying channels on the time coherence of RF fingerprint structures.

• 한국재료학회지
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• 제13권4호
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• pp.259-265
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• 2003

For the aim of thin microwave absorbers used in mobile telecommunication frequency band, this study proposed a high permittivity dielectrics(λ/4 spacer) coated with ITO thin films of 377 $\Omega$/sq(impedance transformer). High frequency dielectric properties of ferroelectric ceramics, electrical properties of ITO thin films and microwave absorbing properties of ITO/dielectrics were investigated. Ferroelectric materials including $BaTiO_3$(BT), 0.9Pb($Mg_{1}$3/Nb$_{2}$3/)$O_3$-0.1 $PbTiO_3$(PMN-PT), 0.8 Pb (Mg$_{1}$3/$Nb_{2}$3/)$O_3$-0.2 Pb($Zn_{1}$3$_Nb{2}$3/)$O_3$(PMN-PZN) were prepared by ceramic processing for high permittivity dielectrics,. The ferroelectric materials show high dielectric constant and dielectric loss in the microwave frequency range. The microwave absorbance (at 2 ㎓) of BT, 0.9PMN-0.1PT, and 0.8PMN-0.2PZN were found to be 60%(at a thickness of 3.5 mm), 20% (2.5 mm), and 30% (2.5 mm), respectively. By coating the ITO thin films on the ferroelectric substrates with λ/4 thickness, the microwave absorbance is greatly improved. Particularly, when the surface resistance of ITO films is closed of 377 $\Omega$/sq, the reflection loss is reduced to -20 ㏈(99% absorbance). This is attributed to the wave impedance matching controlled by ITO thin films at a given thickness of high permittivity dielectrics of λ/4 (3.5 mm for BT, 2.5 mm for PMN-PT and PMN-PZN at 2 ㎓). It is, therefore, successfully proposed that the ITO/ferroelectric materials with controlled surface resistance and high dielectric constant can be useful as a thin microwave absorbers in mobile telecommunication frequency band.

• Journal of Medicine and Life Science
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• 제19권2호
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• pp.46-56
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• 2022

The incidence of fever complicating percutaneous coronary intervention (PCI) is rare. However, little is known regarding the cause of fever after PCI. Therefore, this study aimed to determine the clinical characteristics of patients with acute myocardial infarction (AMI), with or without fever, after PCI. We enrolled a total of 926 AMI patients who underwent PCI. Body temperature (BT) was measured every 4 hours or 8 hours for 5 days after PCI. Patients were divided into two groups according to BT as follows: BT<37.7℃ (no-fever group) and BT ≥37.7℃ (fever group). The 2 years clinical outcomes were compared subsequently. Fever after PCI was associated with higher incidence of major adverse cardiac events (MACE) (hazard ratio [HR], 1.56; 95% confidence interval [CI], 1.07-2.28; P=0.021), all-cause death (HR, 2.32; 95% CI, 1.18-4.45; P=0.014), cardiac death (CD) (HR, 2.57; 95% CI, 1.02-6.76; P=0.049), and any revascularization (HR, 1.69; 95% CI, 1.02-2.81; P=0.044) than without fever. In women, prior chronic kidney disease, lower left ventricular (LV) ejection fraction, higher LV wall motion score index, white blood cell count, peak creatine kinase-myocardial band level, and longer PCI duration were associated with fever after PCI. Procedures such as an intra-aortic balloon pump, extracorporeal membrane oxygenation, continuous renal replacement therapy, central and arterial line insertion, and cardiopulmonary resuscitation were related to fever after PCI. Fever after PCI in patients with AMI was associated with a higher incidence of MACE, all-cause death, CD, and any revascularization at the 2 years mark than in those without fever.

• 한국응용곤충학회지
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• 제36권4호
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• pp.341-350
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• 1997

Autographa californica 핵다각체병 바이러스(AcNPV)의 다각체 단백질과 Bacillus thuringiensis(Bt) cryIA(c) 내독소 단백질의 융합단백질을 생산하는 새로운 재조합 바이러스를 제작하고, 곤충세포주(Spodoptera frugiperda 9)에서 발현된 융합단백질의 특성을 분석하였다. Bt kurstaki HD-73의 cryIA(c) 내독소 단백질 유전자의 N-발단 AcNPV의 완전한 다각체 단백질 유전자의 앞쪽에 융합함에 의하여 또는 다닥체 단백질 유전자내의 제한효소 HindII부위에 삽입함에 의하여 다각체 단백질 유전자의 프로모터 조절하에 도입하였다. 이렇게 작성된 재조합 바이러스를 각각 Btrusl 또는 BtrusII라고 명명하였다. BtrusI은 분명히 단일 전사체를 보임에도 92kDa의 융합 단백질과 다각체 단백질의 두 단백질을 생산하였다. 또한 Btrusl에 의해 만들어진 융합 단백질은 다각체를 형성하지 않았다. 한편, BtrusII에 의해 감염된 곤충세포주에서는 33kDa의 다각체 단백질은 보이지 않았고 단지 융합 단백질만 생산하였으나 다각체는 형성하지 않았다. 따라서 Btrusl에 의해 생산된 융합 단백질의 독성을 조사하기 위하여, Btrusl으로 감염된 곤충세포주를 2령 누에(Bombyx mori)에 접종한 결과 융합 단백질에 의한 독성이 관찰되었다. 결론적으로 다각체 단백질과 Bt cryIA(c) 내독소 단백질에 의한 융합 단백질이 독성을 가지고 있음을 확인하였다.