• ETRI Journal
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• v.43 no.3
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• pp.511-523
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• 2021

The World Health Organization provides guidelines for managing the particulate matter (PM) level because a higher PM level represents a threat to human health. To manage the PM level, a procedure for measuring the PM value is first needed. We use a PM sensor that collects the PM level by laser-based light scattering (LLS) method because it is more cost effective than a beta attenuation monitor-based sensor or tapered element oscillating microbalance-based sensor. However, an LLS-based sensor has a higher probability of malfunctioning than the higher cost sensors. In this paper, we regard the overall malfunctioning, including strange value collection or missing collection data as anomalies, and we aim to detect anomalies for the maintenance of PM measuring sensors. We propose a novel architecture for solving the above aim that we call the hypothesis pruning generative adversarial network (HP-GAN). Through comparative experiments, we achieve AUROC and AUPRC values of 0.948 and 0.967, respectively, in the detection of anomalies in LLS-based PM measuring sensors. We conclude that our HP-GAN is a cutting-edge model for anomaly detection.

• Electronics and Telecommunications Trends
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• v.37 no.3
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• pp.41-51
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• 2022

This article presents an overview of the key technologies in the communications payload of broadband LEO satellite communications systems. In recent years, new developments have been realized for LEO satellite communications. SpaceX's Starlink, a technology leader in this field, offers premium services with satellites carrying in-house developed communications payloads. OneWeb, Amazon, Telesat, and Boeing are also developing LEO satellite communications payloads. The communications payload consists of user link antennas, inter-satellite link communications equipment, feeder link antennas, and a digital processor. Highly sophisticated technologies of compact active phased array antennas for generating multiple hopping beams and light laser communication equipment for ultra-high-speed inter-satellite communication will be applied to next- generation payloads.

• Journal of Pharmacopuncture
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• v.27 no.2
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• pp.172-176
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• 2024

Warts caused by the human papillomavirus (HPV) are generally treated with cryotherapy, CO₂ laser ablation, interferon injections, and bleomycin injections. However, it is sometimes difficult to treat children because the treatment can be painful. In addition, recurrence may occur after treatment. In this study, warts completely disappeared following the administration of herbal medicine in two children, with warts in multiple parts of the hands and around the nails. Two pediatric patients visited the hospital for treatment of warts around their fingers and nails. Both patients received Taeeumjowi-tang (TJT) as a decoction for 60 days. TJT was performed twice per day for the 11-year-old patient and once per day for the 7-year-old patient. Patient progress was observed monthly, and the visual condition of the warts was photographed during the visits. After approximately two months of treatment, the warts disappeared from the fingers and nails of both patients. This case study suggests that the oral administration of TJT may be effective for pediatric patients with warts. Further studies are required to determine the efficacy and safety of these therapies.

• International conference on construction engineering and project management
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• 2024.07a
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• pp.501-508
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• 2024

Building Information Model (BIM) is increasingly being used in the research of construction. The demand for low-cost and efficient access to architectural models is also on the rise. However, generating a parametric model from a point cloud will face interference from other facilities and will be affected by the quality of the measured point cloud. This paper describes a method for generating parametric models from laser-scanned point clouds. With slice voxel selection and line segment detection, the structural framework of the walls can be quickly extracted. By reducing the impact of missing furniture and data on the room, the new approach is applicable to most raw point clouds. This method has potential in multiple directions such as rapid BIM modeling, large-scale room reconstruction, and robot spatial perception.

• Journal of the Korean Society for Nondestructive Testing
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• v.26 no.2
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• pp.108-114
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• 2006

Transient and asymmetric density distributions of butane flow have been investigated from laser image signals by developed three-dimensional digital speckle tomography. Moved signals of speckles have been captured by multiple CCD images in three angles of view simultaneously because the flows were asymmetric and transient. The signals of speckle movements between no flow and downward butane flow from a circular half opening have been calculated by a cross-correlation tracking method so that those distances can be transferred to deflection angles of laser rays fur density gradients. The three-dimensional density fields have been reconstructed from the fringe shift signal which is integrated from the deflection angle by a real-time multiplicative algebraic reconstruction technique (MART).

• Journal of the Korean Society for Precision Engineering
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• v.24 no.4 s.193
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• pp.115-122
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• 2007

Recently, remarkable progress has been made in both technology and production of optical elements including aspheric lens. Especially, requirements for machining glass materials have been increasing in terms of limitation on using environment, flexibility of material selection and surface accuracy. In the past, precision optical glass lenses were produced through multiple processes such as grinding and polishing, but mass production of aspheric lenses requiring high accuracy and having complex profile was rather difficult. In such a background, the high-precision optical GMP process was developed with an eye to mass production of precision optical glass parts by molding press. This GMP process can produce with precision and good repeatability special form lenses such as camera, video camera, aspheric lens for laser pickup, $f-\theta$ lens for laser printer and prism, and me glass parts including diffraction grating and V-grooved base. GMP process consist a succession of heating, forming, and cooling stage. In this study, as a fundamental study to develop molds for GMP used in fabrication of glass lens, we conducted a glass lens forming simulation. In prior to, to determine flow characteristics and coefficient of friction, a compression test and a compression farming simulation for PBK40, which is a material of glass lens, were conducted. Finally, using flow stress functions and coefficient of friction, a glass lens forming simulation was conducted.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.26 no.2
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• pp.137-140
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• 2015

Neurofibroma is characterized as a benign, slow growing neoplasm, originating from Schwann cells or fibroblast in peripheral nerve sheaths. It may appear as a solitary tumor or have multiple localizations in von Recklinghausen disease. They are commonly found in the gastrointestinal tract and laryngeal neurofibromas are extremely rare, accounting for only 0.03 to 0.1% of benign tumors of the larynx. The aryepiglottic fold and arytenoid are the common site of occurrence for laryngeal neurofibroma, because the branch of the superior laryngeal nerve is involved. We present a case of solitary plexiform neurofibroma arising from the laryngeal surface of epiglottis in a 55-year old female who found the lesion incidentally. We removed the tumor completely by transoral laser surgery and no recurrence was found after 7 months. The case of solitary neurofibroma arising from laryngeal surface of epiglottis has not been reported in Korea. We report this case regarding the diagnosis and treatment with review of literatures.

• The Korean Journal of Ceramics
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• v.6 no.3
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• pp.258-261
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• 2000

Highly (h00)-oriented (Ba, Sr)TiO$_3$(BST) thin films were grown by pulsed laser deposition on the perovskite LaNiO$_3$(LNO) metallic oxide layer as a bottom electrode. The LNO films were deposited on SiO$_2$/Si substrates by rf-magnetron sputtering method. The crystalline phases of the BST film were characterized by x-ray $\theta$-2$\theta$, $\omega$-rocking curve and $\psi$-scan diffraction measurements. The surface microsturcture observed by scanning electron microscopy was very dense and smooth. The low-frequency dielectric responses of the BST films grown at various substrate temperatures were measured as a function of frequency in the frequency range from 0.1 Hz to 10 MHz. The BST films have the dielectric constant of 265 at 1 kHz and showed multiple dielectric relaxation at the low frequency region. The origin of these low-frequency dielectric relaxation are attributed to the ionized space charge carriers such as the oxygen vacancies and defects in BST film, the interfacial polarization in the grain boundary region and the electrode polarization. We studied also on the capacitance-voltage characteristics of BST films.

• Restorative Dentistry and Endodontics
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• v.27 no.3
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• pp.257-269
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• 2002

Objective : The purpose of this study was to evaluate the resin infiltration into dentin of one-bottle adhesive systems and self-etching primer bonded to Class V cavities using confocal laser scanning microscope(CLSM). Material and Methods : Forty Class V cavities were prepared from freshly extracted caries-free Human teeth. These teeth were divided into two groups based on the presence of cervical abrasion: Group I, cervical abrasion : Group II, wedge-shaped cavity preparation. Resin-dentin interfaces were produced with two one-bottle dentin bonding systems-ONE COAT BOND(OCB; Coltene$^R$) and Syntac$^R$SPrint$^{TM}$(SS; VIVADENT)-, one self-etching priming system-CLEARFIL$^{TM}$ SE BOND (SB : KURARAY)- and one multi-step dentin bonding system-Scotchbond$^{TM}$Multi-Purpose (SBMP, 3M Dental Products)-as control according to manufacturers' instructions. Cavities were restored with Spectrum$^{R}$(Dentsply). Specimens were immersed in saline for 24 hours and sectioned longitudinally with a low-speed diamond disc. The resin-dentin interfaces were microscopically observed using CLSM. The quality of resin-infiltrated dentin layers were evaluated by five dentists using 0~4 scale. Results : Confocal laser scanning microscopal investigations using primer labeled with rhodamine B showed that the penetration of the primer occurred along the cavity margins. Statistical analysis using one-way ANOVA followed by Duncan's Multiple Range test revealed that the primer penetration of the group 2(wedge-shaped cavity preparation) was more effective than group 1(cervical abrasion) and that of the gingival interfaces was more effective than the occlusal interfaces. In the one-bottle dentin bonding systems, the resin penetration score of OCB was compatible to SBMP, but those of SS and self-etching priming system, SB were lower than SBMP.

• The Korean Journal of Pain
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• v.33 no.1
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• pp.66-72
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• 2020

Background: Low back pain secondary to discopathy is a common pain disorder. Multiple minimally invasive therapeutic modalities have been proposed; however, to date no study has compared percutaneous laser disc decompression (PLDD) with intradiscal injection of radiopaque gelified ethanol (DiscoGel^®). We are introducing the first study on patient-reported outcomes of DiscoGel^® vs. PLDD for radiculopathy. Methods: Seventy-two patients were randomly selected from either a previous strategy of PLDD or DiscoGel^®, which had been performed in our center during 2016-2017. Participants were asked about their numeric rating scale (NRS) scores, Oswestry disability index (ODI) scores, and progression to secondary treatment. Results: The mean NRS scores in the total cohort before intervention was 8.0, and was reduced to 4.3 in the DiscoGel^® group and 4.2 in the PLDD group after 12 months, which was statistically significant. The mean ODI score before intervention was 81.25% which was reduced to 41.14% in the DiscoGel^® group and 52.86% in the PLDD group after 12 months, which was statistically significant. Between-group comparison of NRS scores after two follow-ups were not statistically different (P = 0.62) but the ODI score in DiscoGel^® was statistically lower (P = 0.001). Six cases (16.67%) from each group reported undergoing surgery after the follow-up period which was not statistically different. Conclusions: Both techniques were equivalent in pain reduction but DiscoGel^® had a greater effect on decreasing disability after 12 months, although the rate of progression to secondary treatments and/or surgery was almost equal in the two groups.