• Journal of KIISE:Information Networking
• /
• v.36 no.5
• /
• pp.369-375
• /
• 2009

Residential broadband networks (RBN) are quickly evolving from xDSL/Cable networks to FTTH services with lOOMbps bandwidth. With the high-speed Internet services, subscribers tend to use web, multimedia, game or file sharing applications. Therefore, performance of RBN is important to the quality of services for users. Typically, Internet service providers (ISPs) are providing their RBN performance results that are measured by subscribers with the dedicated measurement tools. However, they do not make their results public to people. In order to obtain the performance results measured by users, we have to induce a lot of subscribers, which will take a lot of cost and time. Monarch, that is used in this paper, could provide the 3rd party measurement method without the help of ISPs and subscribers. With the extensive experiments through Monarch, we have shown that 3rd party measurement results are not much different from those of user-initiated measurement. In addition, we have observed that bandwidth is around $80{\sim}90Mbps$ and RTT is less than 30ms in FTTH services provided by three major Korean ISPs.

• Restorative Dentistry and Endodontics
• /
• v.44 no.1
• /
• pp.1.1-1.12
• /
• 2019

Objectives: The aim of this in vitro study was to test the effect of 2 finishing-polishing sequences (QB, combining a 12/15-fluted finishing bur and an EVO-Light polisher; QWB, adding a 30-fluted polishing bur after the 12/15-fluted finishing bur used in the QB sequence) on 5 nanotech-based resin composites (Filtek Z500, Ceram X Mono, Ceram X Duo, Tetric Evoceram, and Tetric Evoceram Bulk Fill) by comparing their final surface roughness and hardness values to those of a Mylar strip control group (MS). Materials and Methods: Twelve specimens of each nanocomposite were prepared in Teflon moulds. The surface of each resin composite was finished with QB (5 samples), QWB (5 samples), or MS (2 samples), and then evaluated (60 samples). Roughness was analysed with an optical profilometer, microhardness was tested with a Vickers indenter, and the surfaces were examined by optical and scanning electron microscopy. Data were analysed using the Kruskal-Wallis test (p < 0.05) followed by the Dunn test. Results: For the hardness and roughness of nanocomposite resin, the QWB sequence was significantly more effective than QB (p < 0.05). The Filtek Z500 showed significantly harder surfaces regardless of the finishing-polishing sequence (p < 0.05). Conclusions: QWB yielded the best values of surface roughness and hardness. The hardness and roughness of the 5 nanocomposites presented less significant differences when QWB was used.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.20 no.6
• /
• pp.313-330
• /
• 2021

In an autonomous driving system equipped with a camera and lidar, depth completion techniques enable dense depth estimation. In particular, using self-supervised learning it is possible to train the depth completion network even without ground truth. In actual autonomous driving, such depth completion should have very short latency as it is the input of other algorithms. So, rather than complicate the network structure to increase the accuracy like previous studies, this paper focuses on network latency. We design a U-Net type network with RegNet encoders optimized for GPU computation. Instead, this paper presents several techniques that can increase accuracy during the process of self-supervised learning. The proposed techniques increase the robustness to unreliable lidar inputs. Also, they improve the depth quality for edge and sky regions based on the semantic information extracted in advance. Our experiments confirm that our model is very lightweight (2.42 ms at 1280x480) but resistant to noise and has qualities close to the latest studies.

• The Korea Journal of Herbology
• /
• v.20 no.2
• /
• pp.17-26
• /
• 2005

Objectives : The study has been undertaken to scrutinize the results of Halloysitum Rubrum before and after physical and chemical manipulation. Methods : I used X-rays diffracted analysis system(Phillips X'Pert - MPD System) on condition of 40Kv, Anode of Cu Ka to grasp the compositions of crude Halloysitum Rubrums which have been from here and there after pulverization them below 200 mesh. X-rays fluorescence analysis system have been used to check the chief elements content of the ore on condition of 40Kv, 95mA. ICP-MS analysis system(Perkin Elmer, Elan 6100)have been used after a micro-elements and a heavy metals take advantage of mixed acid were dissolved completely. Results : The compositions of the ore Halloysitum Rubrum are composed of large amount of Halloysite and Kaolinite, and small amount of Hematite, Alum, quartzite. The chief elements content of the ore Halloysitum Rubrum are composed of Al and Si. A heavy metals in Halloysitum Rubrum are As, Cd, Cr, Cu, Pb, Zn, etc. As and Zn's amounts was lessen after physical and chemical manipulation Halloysitum Rubrum are decreased at $400^{\circ}C\;and\;450-500^{\circ}C$ each by heat analysis system. Conclusion : Results of this study show that Halloysitum Rubrum can be used in a diverse ways to treat many kinds of disease.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2011.02a
• /
• pp.171-171
• /
• 2011

Co and Fe doped multi-wall carbon nano-tubes (MWCNTs) synthesized by microwave plasma enhanced chemical vapor deposition (PECVD) technique are investigated with synchrotron radiations at Pohang Light Source (PAL) and European Synchrotron Radiation Facility (ESRF). Near edge x-ray absorption spectroscopy (NEXAFS) measurement at C K, Co $L_{3,2}$ and Fe $L_{3,2}$-edges, and x-ray magnetic circular dichroism (XMCD) at Co and Fe $L_{3,2}$-edges have been carried at 7B1 XAS KIST and 2A MS beamline, respectively, to understand the electronic structure and responsible magnetic interactions at room temperature. X-ray absorption spectroscopy (XAS) at C K-edge shows significant p-bonding and Co and Fe L-edges proves the presence of $Co^{2+}$ and $Fe^{2+}$ in octahedral symmetry. Co and Fe doped MWCNTs show good XMCD spectra at 300K. The effect on the magnetism is also studied through swift heavy ion (SHI) radiations and magnetism is found enhanced and change in the electronic structure in Co-CNTs is investigated.

• Journal of Conservation Science
• /
• v.31 no.3
• /
• pp.181-192
• /
• 2015

This study aims to examine production technique of twelve white wares from the Gangneung Namyang-ri and Donghae Balhan-dong2(Samun-dong) kiln sites, Kangwon Province and characteristics of the used materials, and to find a correlation among materials of the excavated white wares. X-ray fluorescence sequential spectroscopy(XRF), X-ray diffraction(XRD), Dilatometer and Inductively coupled plasma mass spectrometry(ICP-MS), Inductively coupled plasma automic emission spectrometer(ICP-AES) were applied to determine the chemical composition, crystalline phase of samples, firing temperatures, trace elements and rare earth elements. When analyzing body crystalline phases of the white wares using the XRD method, quartz and mullite were extracted from all the samples. Though firing temperature of each sample was different, they were mostly fired at a temperature below $1200^{\circ}C$. Analyzing the excavated white wares using the Seger formula, compositional properties of white wares in Gangneung Namyang-ri kiln showed diffrently from the Donghae Balhan-dong2(Samun-dong) kiln. The body of white wares from Gangneung Namyang-ri kiln have higher raito of $RO_2$ and $RO+R_2O$ than of white wares from Donghae Balhan-dong2(Samun-dong) kiln site. The white wares from Gangneung Namyang-ri kiln and Donghae Balhan-dong2(Samun-dong) kiln were made of host rocks of the different geological origin, according to the result of rare earth elements analysis.

• Analytical Science and Technology
• /
• v.7 no.1
• /
• pp.103-114
• /
• 1994

The elution behaviors of Ni(II), Cu(II), Co(II), and Cr(II) in 1-phenyl-3-methyl-4(2-hydroxy-5-X-phenylazo)-5-pyrazolone, [Pm(2-OH)(5-X)PaPz](X=H, $CH_3$, $NO_2$, Cl) chelates have been studied by reversed phase HPLC. Thirteen metal-[Pm(2-OH)(5-X)PaPz] chelates were prepared and characterized by UV, IR, MS, and ICP spectroscopic methods. These metal-2-hydroxyarylazopyrazolone chelates were successfully separated on Novapak-$C_{18}$ column using methanol/water mixtures as a mobile phases. It was found that the chelates were eluted properly in an acceptable range of the capacity factor value($0{\leq}log\;k^{\prime}{\leq}1$). The dependence of the capacity factor(log k') on the volume fraction of water in the binary mobile phase showed a good linearity. Also, there was a good linear dependence of the capacity factor on the liquid-liquid extraction distribution ratio($D_c$) in methanol-water/n-pentadecane extraction system by the batch method. It suggested that the retention of the chelates in the reverse phase liquid chromatographic system be largely due to the solvophobic effect.

• Journal of the Mineralogical Society of Korea
• /
• v.21 no.2
• /
• pp.177-182
• /
• 2008

The Gemological characteristics of B.C. jade from Cassiar Mine, British Colombia, Canada, have been investigated, using polarizing microscopy, Mohs' hardness, refractive index and density measurements, X-ray powder diffraction, X-ray fluorescence spectrometry, ICP-MS, Infrared absorption spectrometry, and DTA/TGA. The B.C. jade is deeply green (spinach peen or olive green) in color and is translucent. It shows a resinous or waxy luster. The principal mineral of the material is tremolite-actinolite solid solution and minor amount of Cr-garnet and unidentified opaque minerals are accompanied. Mohs' hardness value ($5.5{\sim}6$). refractive index (1.62), and specific gravity (3.01) are measured. It is very highly tough and shows hackly fracture. The high Fe content ($Fe_2O_3\;4.14{\sim}4.66\;wt%$) in B.C. jade is attributable to a deepening of green color of the material. The B.C. jade starts to dehydrate at v and dehydration is completed at $1000.8^{\circ}C$, transforming tremolite-actinolite solid solution to enstatite, diopside, quartz, and water in its place. This possible reaction is supported by the weight loss of B.C. jade (1.93 wt%) at $1000.8^{\circ}C$ indicated by TGA curve.

• Journal of Conservation Science
• /
• v.30 no.3
• /
• pp.249-261
• /
• 2014

This study aims to examine production technique of white wares from the Guyre-2ri 1st and 2nd kiln sites, Wonju, Gangwon Province and characteristics of the used materials, and to find a correlation among materials of the excavated white wares. X-ray fluorescence sequential spectroscopy(XRF), X-ray diffraction(XRD), Dilatometer and Inductively coupled plasma mass spectrometry(ICP-MS), Inductively coupled plasma automic emission spectrometer(ICP-AES) were applied to determine the chemical composition, crystalline phase of samples, firing temperatures, trace elements and rare earth elements. White wares from the Guyre-2ri kiln sites contained high contents of coloring oxides and fluxes. Though firing temperature of each sample was different, they were mostly fired at a temperature below $1200^{\circ}C$ and some of them experienced a low temperature of $1000^{\circ}C{\pm}20^{\circ}C$ and a high temperature above $1200^{\circ}C$. When analyzing body crystalline phases of the white wares using the XRD method, quartz and mullite were extracted from all the samples, and the proportions were similar to each other. When analyzing the excavated white wares using the Seger formula, also, all the samples showed similar clay sources and production techniques. Moreover, the white wares were made of host rocks of the same geological origin, according to the result of rare earth elements analysis.

• Journal of Crop Science and Biotechnology
• /
• v.11 no.2
• /
• pp.107-110
• /
• 2008

A high-efficiency, reproducible somatic embryogenesis system for strawberry cultivar Chandler was developed. Thirty-one somatic embryos per explant(max no.) were recorded in leaf discs which were cultured on medium containing MS salts+$B_5$ vitamins+2% glucose+4.0 mg $1^{-1}$TDZ(Thidiazuron) and incubated at $10{\pm}1^{\circ}C$ under darkness for one week followed by three weeks under 16-h photoperiod. The scanning electron microscopic(SEM) ontogeny revealed the normal development of somatic embryos from globular to heart-shaped and dissection microscopy from torpedo-shaped to cotyledonary-stage embryos. The maximum germination percentage of 48% could be obtained on MS medium containing kinetin(1.0 mg $1^{-1}$) and the maximum survival percentage(79%) of plantlets after four weeks was found to be in the mixture of vermiculite, peatmoss, and soilrite(1:1:1).