• Journal of electromagnetic engineering and science
• /
• 제10권3호
• /
• pp.158-165
• /
• 2010

This study reviewed terahertz technologies of time domain spectroscopy, T-ray imaging, and high rate wireless data transfer. The main topics of the terahertz research area were investigation of materials and package modules for terahertz wave generation and detection, and setup of the terahertz system for time domain spectroscopy(TDS), T-ray imaging and sub-THz wireless communication. In addition to Poly-GaAs film as a photoconductive switching antenna material, a table-top scale for the THz-TDS/imaging system and terahertz continuous wave(CW) generation systems for sub-THz data transfer and narrow band T-ray imaging were designed. Dielectric properties of ferroelectric BSTO($Ba_xSr_{1-x}TiO_3$) films and chalcogenide glass systems were characterized with the THz-TDS system at the THz frequency range. Package modules for terahertz wave transmitter/receiver(Tx/Rx) photoconductive antenna were developed.

• 천문학회지
• /
• 제38권4호
• /
• pp.463-470
• /
• 2005

In this paper, we have made the component-based development of observational software for KASI solar imaging spectrograph (KSIS) that is able to obtain three-dimensional imaging spectrograms by using a scanning mirror in front of the spectrograph slit. Since 2002, the KASI solar spectrograph has been successfully operated to observe solar spectra for a given slit region as well as to inspect the response functions of narrow band filters. To improve its capability, we have developed the KSIS that can perform sequential observations of solar spectra by simultaneously controlling the scanning mirror and the CCD camera via Visual C++. Main task of this paper is to introduce the development of the component-based software for KSIS. Each component of the software is reusable on the level of executable file instead of source code because the software was developed by using CBD (component-based development) methodology. The main advantage of such a component-based software is that key components such as image processing component and display component can be applied to other similar observational software without any modifications. Using this software, we have successfully obtained solar imaging spectra of an active region (AR 10708) including a small sunspot. Finally, we present solar $H{\alpha}$ spectra ($6562.81{\AA}$) that were obtained at an active region and a quiet region in order to confirm the validity of the developed KSIS and its software.

• Asian Pacific Journal of Cancer Prevention
• /
• 제17권4호
• /
• pp.1631-1635
• /
• 2016

Helicobacter pylori infection plays an important role in the pathogenesis of chronic gastritis, peptic ulcer disease and gastric malignancy. A diagnosis of infection is thus an important part of a treatment strategy of many gastrointestinal tract diseases. Many diagnostic tests are available but all have some limitations in different clinical situations and laboratory settings. A single gold standard cannot available, but be used for diagnosis of Helicobacter pylori infection in daily clinical practice in all areas, so several techniques have been developed to give reliable results, especially focusing on real time endoscopic features. The narrow band imaging system (NBI) and high resolution endoscopy are imaging techniques for enhanced visualization of infected mucosa and premalignant gastric lesions. The aim of this article is to review the current diagnostic options and possible future developments detection of Helicobacter pylori infection.

• 대한기관식도과학회지
• /
• 제15권2호
• /
• pp.30-35
• /
• 2009

Lung cancer could be developed through a series of morphological changes from dysplasia to carcinoma in situ and then invasive cancer. However, precancerous lesions are generally a few cell layers thick and are detected only by chance. Autofluorescence bronchoscopy(AFB) is one of the newly developed diagnostic tools to detect the pre-cancerous lesions m the bronchial tissue. Several studies have shown that AFB improved the rate of detection of cancer and dysplastic lesions of the airway, especially those in intraepithelial stage. However, there were high rates of false positive with AFB, and it is also important to develop non-biopsy methods because of lack of accurate information of variable course of preneoplastic lesions regarding progression. So, many other technologies were developed, such as narrow band imaging(NBI), endobronchoscopic ultrasound, optical coherence tomography, and confocal fluorescence microendoscopy. Among the new machines, NBI is a new optical technology that can clearly visualize the microvascular structure m the mucosal layer. NBI seems to increase specificity without compromising sensitivity. In the future such techniques would make it possible to precisely study in detail the natural history of the premalignant epithelium.

• 천문학회보
• /
• 제41권1호
• /
• pp.52.1-52.1
• /
• 2016

We introduce the characteristics and performance of the 0.25m telescope at Mangpo high school Unmanned Robotic Observatory (MURO) which was established in Yangpyeong-gun, Gyeongi-do, KOREA in 2015 January. MURO system included Astrohaven 2.1m non-rotation fiberglass clamshell dome, Paramount MEII mount, Takahashi CCA 0.25m wide field telescope, FLI PL 16803 4K CCD with 7-positions filter wheel system, all sky camera and point grey wide field camera, IR 4 chanel heat sensor camera for security, DAVIS realtime weather cast, and power controled by ARS system. All control softwares are from off-the-shelf products based on Windows 7 OS to be easily operated and maintained. We expect to perform variety of science programs ranging from supernovae follow-up observation to narrow band imaging survey as well as science class activities at Mangpo high school.

• Clinical Endoscopy
• /
• 제51권6호
• /
• pp.534-540
• /
• 2018

From dye-assisted conventional chromoendoscopy to novel virtual chromoendoscopy, image-enhanced endoscopy (IEE) is continuously evolving to meet clinical needs and improve the quality of colonoscopy. Dye-assisted chromoendoscopy using indigo carmine or crystal violet, although slightly old-fashioned, is still useful to emphasize the pit patterns of the colonic mucosa and predict the histological structures of relevant lesions. Equipment-based virtual chromoendoscopy has the advantage of being relatively easy to use. There are several types of virtual chromoendoscopy that vary depending on the manufacturer and operating principle. IEE plays distinctive roles with respect to histologic characterization of colorectal polyps and prediction of the invasion depth of colorectal cancers. In addition, the newest models of IEE have the potential to increase adenoma and polyp detection rates in screening colonoscopy.

• Current Optics and Photonics
• /
• 제4권6호
• /
• pp.530-539
• /
• 2020

Hyperspectral images feature a relatively narrow band and are easily disturbed by noise. Accurate estimation of the types and parameters of noise in hyperspectral images can provide prior knowledge for subsequent image processing. Existing hyperspectral-noise estimation methods often pay more attention to the use of spectral information while ignoring the spatial information of hyperspectral images. To evaluate the noise in hyperspectral images more accurately, we have proposed a spectral-spatial cooperative noise-evaluation method. First, the feature of spatial information was extracted by Gabor-filter and K-means algorithms. Then, texture edges were extracted by the Otsu threshold algorithm, and homogeneous image blocks were automatically separated. After that, signal and noise values for each pixel in homogeneous blocks were split with a multiple-linear-regression model. By experiments with both simulated and real hyperspectral images, the proposed method was demonstrated to be effective and accurate, and the composition of the hyperspectral image was verified.

• 대한후두음성언어의학회지
• /
• 제33권1호
• /
• pp.13-19
• /
• 2022

Vocal fold leukoplakia poses a challenge to otolaryngologists due to its various spectrum of pathologic diagnosis. The degree of dysplasia is associated with malignancy risk and the new 2017 WHO classification system changed from the 3-tier system to a 2-tier system consisting of low and high grades. Infections including candidiasis, cryptococcosis, and tuberculosis should also be included in the differential diagnosis. Efforts have been made to evaluate risks using endoscopic technologies such as narrow band imaging, and surgery is essential for histopathological diagnosis. Regarding management, it is important to make an accurate diagnosis and find a balance between oncologic safety and functional outcome.

• Clinical Endoscopy
• /
• 제56권2호
• /
• pp.261-261
• /
• 2023

• 천문학회지
• /
• 제52권6호
• /
• pp.235-244
• /
• 2019

We present the results of near-infrared imaging observations of the galaxy overdensity around the z = 1.44 radio-loud active galactic nucleus (AGN) 6CE1100+3505, which was carried out with the purpose of sampling the redshifted Hα emission from the actively star-forming galaxies that could constitute the overdensity. The existence of the structure around this AGN was spectroscopically confirmed by previous grism observations which are however limited to the central region. Using the CH4Off narrow/medium-band and H broad band filters in the Wide Infrared Camera (WIRCam) on the Canada-France-Hawaii Telescope (CFHT), we constructed a sample of objects that show a flux excess in the CH4Off band due to line emission. The emission line flux is ~ 4.9 × 10^-16 erg s^-1 cm^-2, corresponding to a star formation rate (SFR) of ~ 50 M_⊙ yr^-1 for galaxies at redshifts z ~ 1.4. None of the galaxies with medium-band flux excess is located within 1 Mpc from the central AGN, and there is no evidence that the selected galaxies are associated with the proposed cluster. Along with the star formation quenching near the center that was found from the previous grism observations, the lack of extreme starbursts in the structure suggests that at z ~ 1.4, overdense regions are no longer favorable locations for vigorous star formation.