• Bulletin of the Korean Chemical Society
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• v.33 no.10
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• pp.3391-3396
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• 2012

Two-dimensional infrared (2D-IR) spectroscopy can probe the fast structural evolution of molecules under thermal equilibrium. Vibrational frequency fluctuation caused by structural evolution produced the time-dependent line shape change in 2D-IR spectrum. A variety of methods has been used to connect the evolution of 2D-IR spectrum with Frequency-Frequency Correlation Function (FFCF), which connects the experimental observables to a molecular level description. Here, a new method to extract FFCF from 2D-IR spectra is described. The experimental observable is the time-dependent frequency shift of maximum peak position in the slice spectrum of 2D-IR, which is taken along the excitation frequency axis. The direct relation between the 2D-IR peak shift and FFCF is proved analytically. Observing the 2D-IR peak shift does not need the full 2D-IR spectrum which covers 0-1 and 1-2 bands. Thus data collection time to determine FFCF can be reduced significantly, which helps the detection of transient species.

• Korean Journal of Veterinary Research
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• v.43 no.3
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• pp.339-347
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• 2003

The regional distribution and relative frequency of some endocrine cells in the pancreas of the Korean aucha perch, Coreoperca herzi Herzenstein belonging to the family Serranidae in order Perciformis, were observed using specific mammalian antisera against serotonin, insulin, glucagon, somatostatin and human pancreatic polypeptide (hPP) by peroxidase antiperoxidase (PAP) method. The pancreas was divided into four portions (principal and secondary islets, exocrine and pancreatic duct regions). In addition, the pancreatic islet regions were further subdivided into three regions (central, mantle and peripheral regions). Spherical to spindle or occasionally round to oval immunoreactive (IR) cells were demonstrated in the pancreatic islets and exoccrine portions, but no cells were detected in the pancreatic duct portions. In the principal islets, serotonin-IR cells were not detected but most of insulin-IR cells were located in the central regions and they were also demonstrated in the mantle and peripheral regions in moderate and rare frequencies, respectively. Glucagon- and hPP-IR cells were mainly situated in the mantle regions but the cells were also demonstrated in the peripheral regions in relatively lower frequency. Somatostatin-IR cells were evenly distributed in the central and mantle regions in a few frequency and cells were also demonstrated in the peripheral regions in rare frequency. Cell clusters were consisted of hPP-IR cells that were situated in the peripheral to mantle regions. In the secondary islet portions, serotonin-IR cells were randomly distributed throughout the whole pancreatic islet regions but lower frequency was detected in the peripheral regions compared to that in central and mantle regions where cells were detected in a few frequency, respectively. Insulin-IR cells were restricted to the central regions in numerous frequency and glucagon-IR cells were evenly distributed in the mantle and peripheral regions in moderate frequencies, respectively. Somatostatin-IR cells were observed in the central and mantle regions in moderate and a few frequencies, respectively. In addition, hPP-IR cells showed similar distributional patterns to those of glucagon-IR cells except cells were also located in the central regions in rare frequency. In the exocrine portions, only glucagon- and hPP-IR cells were demonstrated in rare and a few frequencies, respectively. In conclusion, the regional distribution and relative frequency of pancreatic endocrine cells of the Korean aucha perch showed general patterns, which were observed in other teleost. However, some species-dependent different distributional patterns and/or relative frequencies were also demonstrated especially to serotonin-IR cells. In pancreas of the Korean aucha perch, insulin-IR cells were the most predominant cell type followed by glucagon-, somatostatin-, hPP- and serotonin-IR cells.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.8
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• pp.1121-1129
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• 2022

Object recognition is carried out using RGB images in various object recognition studies. However, RGB images in dark illumination environments or environments where target objects are occluded other objects cause poor object recognition performance. On the other hand, IR images provide strong object recognition performance in these environments because it detects infrared waves rather than visible illumination. In this paper, we propose an RGB-IR fusion model, high-frequency interchange network (HINet), which improves object recognition performance by combining only the strengths of RGB-IR image pairs. HINet connected two object detection models using a mutual high-frequency transfer (MHT) to interchange advantages between RGB-IR images. MHT converts each pair of RGB-IR images into a discrete cosine transform (DCT) spectrum domain to extract high-frequency information. The extracted high-frequency information is transmitted to each other's networks and utilized to improve object recognition performance. Experimental results show the superiority of the proposed network and present performance improvement of the multispectral object recognition task.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.12C
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• pp.1184-1191
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• 2009

We aim at frequency offset estimation for IEEE 802.15.4a ranging systems, where an impulse-radio ultra-wideband (IR-UWB) signal is exploited, By incorporating the property of the ternary code in the preamble, we derive a simplified maximum-likelihood (ML) estimation of the frequency offset. In addition, a closed form estimator for implementation is investigated. Simulation results and theoretical analysis verify our estimators in IEEE 802.15.4a IR-UWB packet-based ranging systems.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.21 no.1
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• pp.59-67
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• 2018

Purpose: to compare cut off points corrected for age and gender (COOP) with fixed cut off points (FCOP) for fasting plasma insulin and Homeostatic model assessment-insulin resistance (HOMA-IR) for the diagnosis of IR in obese children and adolescents and their correlation with dyslipidemia. Methods: A multicenter, cross-sectional study including 383 subjects aged 7 to 18 years, evaluating fasting blood glucose, plasma insulin, and lipid profile. Subjects with high insulin levels and/or HOMA-IR were considered as having IR, based on two defining criteria: FCOP or CCOP. The frequency of metabolic abnormalities, the presence of IR, and the presence of dyslipidemia in relation to FCOP or CCOP were analyzed using Fisher and Mann-Whitney exact tests. Results: Using HOMA-IR, IR was diagnosed in 155 (40.5%) and 215 (56.1%) patients and, using fasting insulin, 150 (39.2%) and 221 (57.7%), respectively applying FCOP and CCOP. The use of CCOP resulted in lower insulin and HOMA-IR values than FCOP. Dyslipidemia was not related to FCOP or CCOP. Blood glucose remained within normal limits in all patients with IR. There was no difference in the frequency of IR identified by plasma insulin or HOMA-IR, both for FCOP and CCOP. Conclusion: The CCOP of plasma insulin or of HOMA-IR detected more cases of IR as compared to the FCOP, but were not associated with the frequency of dyslipidemia. As blood glucose has almost no fluctuation in this age group, even in the presence of IR, fasting plasma insulin detected the same cases of IR that would be detected by HOMA-IR.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.2
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• pp.159-168
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• 2012

In this paper, we designed the antipodal vivaldi antenna for IR-UWB systems application and evaluated IR-UWB antenna performance for the ultra wideband impulse signal transmission in the time- and frequency-domain. The designed antipodal vivaldi antenna was fabricated using FR-4 substrate which thickness 1.6 mm, dielectric constant ${\epsilon}_r=4.7$ and $tan{\delta}=0.002$. We measured the return loss, far filed radiation pattern at the anechoic chamber in the frequency-domain. We also performed the pulse fidelity analysis in the time-domain using nano-second impulse signal transmission and demonstrated the feasibility of ultra wideband signal stable transmission in the UWB band. The designed and fabricated antipodal vivaldi antenna could be emitting and receiving the IR-UWB signal while preserving low pulse distortion and good radiation pattern in time- and frequency-domain.

• ETRI Journal
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• v.36 no.3
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• pp.510-513
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• 2014

A Q-band pHEMT image-rejection low-noise amplifier (IR-LNA) is presented using inter-stage tunable resonators. The inter-stage L-C resonators can maximize an image rejection by functioning as inter-stage matching circuits at an operating frequency ($F_{OP}$) and short circuits at an image frequency ($F_{IM}$). In addition, it also brings more wideband image rejection than conventional notch filters. Moreover, tunable varactors in L-C resonators not only compensate for the mismatch of an image frequency induced by the process variation or model error but can also change the image frequency according to a required RF frequency. The implemented pHEMT IR-LNA shows 54.3 dB maximum image rejection ratio (IRR). By changing the varactor bias, the image frequency shifts from 27 GHz to 37 GHz with over 40 dB IRR, a 19.1 dB to 17.6 dB peak gain, and 3.2 dB to 4.3 dB noise figure. To the best of the authors' knowledge, it shows the highest IRR and $F_{IM}/F_{OP}$ of the reported millimeter/quasi-millimeter wave IR-LNAs.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.12
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• pp.1371-1379
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• 2010

This paper presents an analysis of impulse dispersion for impulse radio ultra-wide band(IR-UWB) antenna. A set of antenna structure configurations are highlighted with verification based on the STFT(Short Time Fourier Transform) in 3.1~5.1 GHz: first, a taper-slotted antenna allowing the optimal impulse transmission, and second, 4 types of the omni-directional IR-UWB antenna using different feed structures(microstrip line, and CPW(Coplanar Waveguide)). The proposed STFT allows the analysis of the IR-UWB antenna's dispersion characteristic.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.215-218
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• 2001

A flame detector responds either to radiant energy visible to the human eye or outside the range of human vision. Such a detector is sensitive to glowing embers, coals, or flames which radiate energy of sufficient intensity and spectral quality to actuate the alarm. An infra-red detectors can respond to the total IR component of the flame alone or in combination with flame flicker in the frequency range of 5 to 30 Hz. A major problem in the use of infrared detectors receiving total IR radiation is the possible interference of solar radiation in the infrared region. When detectors are located in places shielded from the sun, such as vaults. filtering or shielding the unit from the sun's rays is unnecessary. In this study, we proposed method for redue a false alarm with using filtering & sensor technology for distinguish of causes of raise a false alarm and pure flame.

• Journal of the Korean Magnetics Society
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• v.16 no.5
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• pp.234-239
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• 2006

We measured the microwave permeability in the frequency range of 100 MHz$\sim$9 GHz in the exchange biased CoFe/MnIr films. The results were analyzed based on the Landau-Lifshitz-Gilbert theory. The initial permeability and ferromagnetic resonance frequency was tuned by controlling the CoFe thickness and unidirectional anisotropy. The tunable range of ferromagnetic resonance frequency was up to 20 GHz in the thin CoFe layer of 1.5 nm. The CoFe/MnIr films showed the high permeability and low loss properties in the microwave frequency range. Thus, this material could be applied to the microwave devices.