• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.4
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• pp.102-110
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• 2009

In this paper, we propose an object detection method for real-time in infrared (IR) images and PowerPC (PPC) and H/W design based on field programmable gate array (FPGA). An open H/W architecture has the advantages, such as easy transplantation of HW and S/W, support of compatibility and scalability for specification of current and previous versions, common module design using standardized design, and convenience of management and maintenance. Proposed background modeling for an open H/W architecture design decreases size of search area to construct a sparse block template of search area in IR images. We also apply to compensate for motion compensation when image moves in previous and current frames of IR sensor. Separation method of background and objects apply to adaptive values through time analysis of pixel intensity. Method of clutter reduction to appear near separated objects applies to median filter. Methods of background modeling, object detection, median filter, labeling, merge in the design embedded system execute in PFC processor. Based on experimental results, proposed method showed real-time object detection through global motion compensation and background modeling in the proposed embedded system.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.2
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• pp.87.2-87.2
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• 2017

RR~Telescopii is a symbiotic nova exhibiting accretion activities through gravitational capture of the slow stellar wind from a Mira variable. We present high resolution spectra of RR~Tel obtained with MIKE and the 6.5 m Magellan-Clay telescope, in which we find broad features with FWHM exceeding $10{\AA}$ at 6545, 6825, 7082, 7023 and $7053{\AA}$. They are formed through Raman-scattering with atomic hydrogen of far-UV He II 1025, O~VI 1032, $1038{\AA}$ and C II 1036 and $1037{\AA}$. We compute the Raman conversion efficiencies using the case B recombination theory for He II emissions, which are used in turn to infer the intrinsic line luminosities of O VI and C II. The Raman O~VI features are characterized by double-peaked profiles with a peak separation ~ 60km/s, pointing out the presence of an accretion disk with a physical size of ~ sub AU. In contrast, Raman C II features exhibit profiles with a simple peak and a narrower width ~40 km/s, indicating that C II is formed in a much more extended region. The weak C II multiplet at 1335, $1336{\AA}$ found in the IUE spectral archive and the absence of C II 1036, $1037{\AA}$ in the FUSE archive show that far-UV C II lines suffer heavy interstellar extinction consistent with the distance of ~ 2.5 kpc to RR Tel.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.8 s.239
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• pp.948-955
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• 2005

A three-dimensional computation was conducted to understand effects of the inlet boundary layer thickness on the internal flow in a low-speed axial compressor operating at the design condition($\phi=85\%$) and near stall condition($\phi=65\%$). At the design condition, the flows in the axial compressor show, independent of the inlet boundary layer thickness, similar characteristics such as the pressure distribution, size of the hub comer-stall, tip leakage flow trajectory, limiting streamlines on the blade suction surface, etc. However, as the load is increased, the hub corner-stall grows to make a large separation region at the junction of the hub and suction surface for the inlet condition with thick boundary layers at the hub and casing. Moreover, the tip leakage flow is more vortical than that observed in case of the thin inlet boundary layer and has the critical point where the trajectory of the tip leakage flow is abruptly turned into the downstream. For the inlet condition with thin boundary layers, the hub corner-stall is diminished so it is indistinguishable from the wake. The tip leakage flow leans to the leading edge more than at the design condition but has no critical point. In addition to these, the severe reverse flow, induced by both boundary layer on the blade surface and the tip leakage flow, can be found to act as the blockage of flows near the casing, resulting in heavy loss.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.5
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• pp.423-430
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• 2014

Noise and vibration, which occur in a pipe, are usually caused by the interaction between the turbulent flow and nearby wall. Although it can be estimated by a simple case of expanded pipes having complex turbulent flow, the radiated noise is highly dependent upon the size, shape, and thickness of the given model. In addition, the radiated noise propagates and has serious interference and destabilization effects on the surrounding systems, which can lead to fatigue fracture and failure. This study took advantage of the variety of commercial programs, such as FLUENT (flow solver), NASTRAN (dynamic motion solver of complex structures) and VIRTUAL LAB (radiated noise solver) based on the boundary element method (BEM), to understand the underlying physics of flow noise. The expanded pipe has separation and a high pressure drop because of the abrupt change in the cross-section. Based on the radiated noise calculations, the noise level was reduced to around 20 dB in the range of 100-500 Hz.

• Applied Chemistry for Engineering
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• v.8 no.1
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• pp.76-83
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• 1997

Blends of thermotropic liquid crystalline polymer(TLCP) with poly(ethylene terephthalate) (PET) were prepared by the coprecipitation from a common solvent. The blends were processed through a capillary die at $287^{\circ}C$ to produce a monofilament. Morphology and mechanical, thermal properties of blends and composites were examined by differential scanning calorimetry(DSC), tensile test, optical microscopy and scanning electron microscopy. Crystallization kinetics of the blends were investigated by the isothermal DSC method. The Avrami analyses were applied to obtain the information on the crystal growth geometry and factors controlling the rate of crystallization. In the blends, liquid crystalline phase did not reveal any significant macrophase separation and thermal degradation at the processing temperature. From scanning electron micrographs of cryogenic fracture surfaces of extruded fibers, the TLCP domains were found to be more or less finely dispersed with $0.1{\mu}m$ to $0.2{\mu}m$ in size. Interfacial adhesion between the TLCP and matrix polymer was excellent. Tensile strength and modulus of TLCP/PET in-situ fiber composites were enhanced with increasing draw ratio and LCP content.

• Applied Chemistry for Engineering
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• v.26 no.6
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• pp.659-665
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• 2015

Loading of hydrophobic ${\alpha}$-tocopherol into nanostructured lipid carrier (NLC) was performed for improving its oxidative stability. First, various NLCs with different constituents and mixing ratios were prepared and their characteristics were investigated. While the stable NLCs were made when cetyl palmitate (CP) or glyceryl monosterate (GMS) was used as a solid lipid, the phase separation occurred in the NLCs consisting of stearic acid. Particle sizes of the NLCs were several hundreds of nanometers and the size decreased with increasing the ratio of solvent to lipid. It was examined from DSC thermogram and anisotropy test that the degree of crystallinity of the lipid phase decreased and the lipid matrix became less ordered when octyldodecanol, a long chain fatty alcohol, was added into the solid lipid. The oxidative stability of ${\alpha}$-tocopherol in NLC was remarkably improved compared to that in solution or emulsion under high temperature ($45^{\circ}C$) and UV radiation, which was verified through DPPH test and peroxide value measurement.

• Membrane and Water Treatment
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• v.11 no.4
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• pp.257-274
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• 2020

There are many previous review articles are available to summarize either the characterization methods of effluent organic matter (EfOM) or the individual control treatment options. However, there has been no attempt made to compare in parallel the physicochemical treatment options that target the removal of EfOM from biological treatments. This review deals with the recent progress on the characterization of EfOM and the novel technologies developed for EfOM treatment. Based on the publications after 2010, the advantages and the limitations of several popularly used analytical tools are discussed for EfOM characterization, which include UV-visible and fluorescence spectroscopy, Fourier transform infrared spectroscopy (FTIR), size exclusion chromatography (SEC), and Fourier transform-ion cyclotron resonance-mass spectrometry (FT-ICR-MS). It is a recent trend to combine an SEC system with various types of detectors, because it can successfully track the chemical/functional composition of EfOM, which varies across a continuum of different molecular sizes. FT-ICR-MS is the most powerful tool to detect EfOM at molecular levels. However, it is noted that this method has rarely been utilized to understand the changes of EfOM in pre-treatment or post-treatment systems. Although membrane filtration is still the preferred method to treat EfOM before its discharge due to its high separation selectivity, the minimum requirements for additional chemicals, the ease of scaling up, and the continuous operation, recent advances in ion exchange and advanced oxidation processes are greatly noteworthy. Recent progress in the non-membrane technologies, which are based on novel materials, are expected to enhance the removal efficiency of EfOM and even make it feasible to selectively remove undesirable fractions/compounds from bulk EfOM.

• Journal of Technologic Dentistry
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• v.27 no.1
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• pp.89-95
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• 2005

In the manufacture of ceramo-metal crown, difference of fracture strength according to the metal depth has been known to be an important influence on enough intensity and internal stress to endure an occlusion-pressure as well as aesthetics of rehabilitating similar colour such as natural teeth. Depth of ceramic material could be determined by that of metal in three groups: first case of thin depth, second case of thick depth, and third case of constant depth. For the enhancement of the fracture strength between metal and ceramic materials and aesthetic satisfaction, a study on the bonding force, fracture strength, and aesthetics have been required more. In this study, therefore metal coping were made in three groups of A, B and C by using both ceramic powder of Norithe and metal of Columbium, which have been used primarily in the market. A group was made in $0.2mm\times10mm\times10mm$, B group was made in $0.4mm\times10mm\times10mm$, and, C group was made in $0.8mm\times10mm\times10mm$, respectively. The number of metal coping in each group was 10, and total sample numbers used in this study were 30 metal copings. After these metal coping tissue were in the process of build-up in 1.5mm constant depth of porcelain, firing, and glazing, the fracture strength about each metal coping tissue was investigated using oil press. It was found that the average values of durable occlusion pressure for separation of ceramic material in the porcelain fused to metal crown (PFM) in the each group showed the increasing order of A group (30 bar), B group (42 bar), and C group (44 bar), respectively. Proper depth of metal coping in the PFM was considered to be 0.4mm in the B group because this metal size showed higher durable property to the occlusion pressure and better coupling strength in the ceramo-metal crown.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.2
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• pp.263-269
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• 2012

Code-Division Multiple-Access(CDMA) allows several users simultaneous access to a common channel by assigning a distinct pseudonoise sequence called spectrum code to each user. Each user in a CDMA system uses a assigned spectrum code to modulate their signal. Choosing the codes used to modulate the signal is very important in the performance of CDMA systems. The best performance will occur when there is good separation between the signal of a desired user and the signals of other users. The receiver synchronizes the code to recover the data. The use of an independent code allows multiple users to access the same frequency band at the same time. In this paper we propose a generalized model of non-linear binary sequence using trace function and analyze cross-correlation of these sequences. These sequences with low correlation, large linear span and large family size, in a direct-sequence spread spectrum communication system, help to minimize multiple access interference, increase security degree of system and enlarge user number.

• Journal of the Korean GEO-environmental Society
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• v.15 no.9
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• pp.59-67
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• 2014

With increasing underwater structure construction, there is high interest in offshore foundation and underwater grout and various study has been done in this area. For grout materials constructed underwater, it may be washed away by water or easily disturbed and material separation phenomenon during curing period always happens. As a result, it is difficult to ensure construction quality and this has a significant influence on the design strength of structure. In this study, to understand application effects of anti-washout admixture for the preplaced construction method, where grout is injected in monopile after filled with aggregates, laboratory tests on bleeding and compressive strength of anti-washout admixture were performed under various test conditions varying size of aggregate, water and cement ratio and admixture, and test results were compared and evaluated.