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Wyświetlanie 1-12 z 12
Tytuł:
The effect of patterns on image-based modelling of texture-less objects
Autorzy:
Hafeez, J.
Jeon, H.-J.
Hamacher, A.
Kwon, S.-C.
Lee, S.-H.
Powiązania:
https://bibliotekanauki.pl/articles/221814.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
structure-from-motion
feature detection
patterns analysis
3D reconstruction
surface comparison
Opis:
The task of generating fast and accurate three-dimensional (3D) models of objects or scenes through a sequence of non-calibrated images is an active field of research. The recent development in algorithm optimization has resulted in many automatic solutions that can provide an accurate 3D model from texture-full objects. Structure-from-motion (SfM) is an image-based method that uses discriminative point-based feature identifier, such as SIFT, to locate feature points in the images. This method faces difficulties when presented with the objects made of homogenous or texture-less surfaces. To reconstruct such surfaces a well-known technique is to apply an artificial variety by covering the surface with a random texture pattern prior to the image capturing process. In this work, we designed three series of image patterns which are tested based on the contrast and density ratio which increases from the first to the last pattern within the same series. The performance of the patterns is evaluated by reconstructing the surface of a texture-less object and comparing it with the true data. Using the best-found patterns from the experiments, a 3D model of a Moai statue is reconstructed. The experimental results demonstrate that the density and structure of a pattern highly affects the quality of the reconstruction.
Źródło:
Metrology and Measurement Systems; 2018, 25, 4; 755-767
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Similarity of chromosome structure among Populus tremula var. davidiana, Populus alba and their hybrids revealed by FISH karyotype analysis
Autorzy:
Kim, Y.G.
Kwon, S.H.
Kang, H.I.
Yoem, D.B.
Kim, K.W.
Kim, H.H.
Kang, K.S.
Powiązania:
https://bibliotekanauki.pl/articles/2077655.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Instytut Dendrologii PAN
Tematy:
Karyotype analysis
Fluorescence in situ hybridization
Ribosomal DNA site
Poplar
Cytogenetics
Opis:
The genus Populus is one of the important tree species in Korean peninsula and many other coun- tries in the world. It represents the model species of forest genomics because it grows fast and reproduces rapidly. In this reason, their genetic characteristics have been well studied and the whole genome has been sequenced completely in some species. However, cytogenetic study of the genus Populus has been limited. In the present study, karyotypes of Korean aspen (P. tremula var. davidiana), Silver poplar (P. alba) and their two hybrids, Suwon aspen (P. tremula var. glandulosa) and Hyun aspen (P. alba × P. tremula var. glandulsa) were analyzed by means of the fluorescence in situ hybridization (FISH). Root samples were collected from mature trees in the demonstration forest, located at Suwon, Kyonggi province in South Korea. The fresh root cells were examined by DAPI (4’,6-diamidino-2-phenylindole) staining and FISH using 45S rDNA and 5S rDNA probes. As the results, the chromosome compositions of all species were the same as 2n = 38. The karyotype formulas of Korean aspen, Silver poplar, Suwon aspen and Hyun aspen were 28m + 6sm + 4st (2sat), 26m + 10sm (2sat) + 2st, 26m + 12sm (2sat) and 28m + 10sm (2sat), respectively. The four species had one pair of 45S rDNA site and one pair of 5S rDNA site in common with FISH karyotypes. The similarity of FISH karyotypes among four species indicated close genetic relationship and coexistence of their interspecific hybrids. This research will provide genetic information on cytogenetic research of Populus and genetic mapping that can be applied to the breeding program of Populus in the near future.
Źródło:
Dendrobiology; 2020, 83; 68-74
1641-1307
Pojawia się w:
Dendrobiology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Morphology of strobili at different development positions and cone and seed characteristics of Pinus densiflora f. multicaulis
Autorzy:
Kwon, S.H.
Kim, Y.G.
Kang, H.I.
Shim, D.
Kang, K.S.
Powiązania:
https://bibliotekanauki.pl/articles/2078259.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Instytut Dendrologii PAN
Tematy:
bisexual strobili
sex reversal
microsporangia
megasporangia
cone analysis
Opis:
Pinus densiflora f. multicaulis is a rare and unusual form of genus Pinus. It has excellent ornamen- tal values due to many trunks from its root collar, and produces female, male, and bisexual strobili on the same tree. However, there is limited study whether the bisexual strobili are functional, mature lateral cones produce filled seeds, and the seeds from the mature lateral cones germinate and grow as well as those from mature apical cones. The structure of apical female, and lateral male and bisexual strobili were analyzed in an open-pollination-progeny population. The strobili were photographed to obtain external, cross-section, and radial-section images using a 45× stereoscopic microscope. Radial sections of strobili were imaged using scanning electron microscopy. Characteristics of apical and lateral cones and seeds were surveyed by cone analysis and germination test. P. densiflora f. multicaulis developed typical female strobili apically, and ordinary male and bisexual strobili laterally. Additionally, female strobili developed laterally whereas the male strobili were normally located. The mature lateral female strobili had the same structure as the apical female. In the mature bisexual strobili, the proportion of male and female tissue was unequal. The cones developed from lateral female strobili showed highly significant differences in the length, width, and weight, being shorter (32.7%), narrower (26.9%), and lighter (59.8%) than those from apical female strobili. Both types produced filled seeds and seedlings, and well significant positive correlations were found among characteristics of seeds from apical and lateral female strobili. The initial seed germination rate of the seeds from apical female strobili was higher than that of seeds from lateral female strobili, but the difference decreased over time. The viability and spatial distribution of the female and male tissue of bisporangiate cones, and their frequent occurrence suggests a common mechanism for the production of bisporangiate structures in seed plants.
Źródło:
Dendrobiology; 2021, 85; 51-59
1641-1307
Pojawia się w:
Dendrobiology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Morphology Change Of Si Deposit In Molten Salt Electrorefining
Zmiana morfologii osadu Si podczas elektrorafinacji w stopionych solach
Autorzy:
Ryu, H. Y.
Kwon, S. C.
Han, M. H.
An, Y. S.
Lee, J. S.
Lee, J. H.
Powiązania:
https://bibliotekanauki.pl/articles/354346.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
molten salt
silicon
morphology
electrorefining
current density
sól stopiona
krzem
morfologia
elektrorafinacja
gęstość prądu
Opis:
The effects of processing parameters on the morphology change in a Si deposit recovered by means of molten salt electrorefining are evaluated using electrochemical techniques such as cyclic voltammetry and chronopotentiometry at 800°C. It was found that concentration of K2SiF6 and current density were important parameters in determining deposit size. Higher concentrations of K2SiF6 were effective in coarsening the silicon deposit and decreasing the cell potential. Silicon nanofiber was recovered at 5 wt% of K2SiF6 whereas dense particles were prepared at 30 and 50 wt% of K2SiF6. The morphology of the Si deposit was determined by the concentration of Si in the electrolyte which is related to the formation of crystal and growth of Si. The formation mechanism of the Si deposit was interpreted by using high resolution TEM as well as electrochemical properties.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1491-1497
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of InAs Coverage on Transition of Size Distribution and Optical Properties of InAs Quantum Dots
Autorzy:
Kim, G.
Jeon, S.
Cho, M.
Choi, H.
Kim, D.
Kim, M.
Kwon, Y.
Choe, J.
Kim, J.
Leem, J.
Powiązania:
https://bibliotekanauki.pl/articles/1535820.pdf
Data publikacji:
2010-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.15.Hi
68.37.Ps
78.55.Cr
78.67.Hc
Opis:
The influence of InAs coverage on the formation of self-assembled quantum dots grown by molecular-beam epitaxy was investigated by atomic force microscopy and photoluminescence measurements. As the InAs coverage increased from 2.0 to 3.0 monolayers, the quantum dot density decreased from 1.1 × $10^{11}$ to 1.36 × $10^{10} cm^{-2}$. This result could be attributed to the coalescence of neighboring small InAs quantum dots resulting in the formation of much larger InAs quantum dots with lower quantum dot density. Atomic force microscopy results revealed that as the InAs quantum dot coverage increased, the transition of size distribution of InAs quantum dots from single-modal to multimodal occurred. The temperature-dependent photoluminescence spectra showed that the photoluminescence spectra red shifted and the photoluminescence peak intensity decreased as the InAs coverage increased. The thermal activation energy was strongly dependent on the InAs coverage, and for InAs quantum dots with 3.0 ML thick InAs coverage, this energy was estimated to be 147 meV.
Źródło:
Acta Physica Polonica A; 2010, 118, 4; 673-676
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Implementation of a Novel Audio Network Protocol
Autorzy:
Lee, J.
Jeon, H.
Choi, P.
Kwon, S.
Lee, S.
Powiązania:
https://bibliotekanauki.pl/articles/178062.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
audio mixer
AoIP
audio over internet protocol
DANTE
SR System
Opis:
Recently, the rapid advancement of the IT industry has resulted in significant changes in audio-system configurations; particularly, the audio over internet protocol (AoIP) network-based audio-transmission technology has received favourable evaluations in this field. Applying the AoIP in a certain section of the multiple-cable zone is advantageous because the installation cost is lower than that for the existing systems, and the original sound is transmitted without any distortion. The existing AoIP-based technology, however, cannot control the audio-signal characteristics of every device and can only transmit multiple audio signals through a network. In this paper, the proposed Audio Network & Control Hierarchy Over peer-to-peer (Anchor) system enables all audio equipment to send and receive signals via a data network, and the receiving device can mix the signals of different IPs. Accordingly, it was possible to improve the system-application flexibility by simplifying the audio-system configuration. The research results confirmed that the received audio signals from different IPs were received, mixed, and output without errors. It is expected that Anchor will become a standard for audio-network protocols.
Źródło:
Archives of Acoustics; 2018, 43, 4; 637-645
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect Of Ti Powder Addition On The Fabrication Of TiO2 Nanopowders
Wpływ dodatku nanoproszku Ti na zagęszczanie i spiekanie nanoproszków TiO2
Autorzy:
Raihanuzzaman, R. M.
Park, H. Y.
Ghomashchi, R.
Kwon, T. H.
Son, H.-T.
Hong, S.-J.
Powiązania:
https://bibliotekanauki.pl/articles/353186.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
TiO2 nanopowder
magnetic pulsed compaction
densification
sintering
nanoproszek Ti
magnetyczne zagęszczanie impulsowe
zagęszczanie
spiekanie
Opis:
Sintered samples of Ti added TiO2 nanopowders were fabricated by combined application of magnetic pulsed compaction (MPC) and sintering. The effect of Ti nano powder on density, shrinkage and hardness of the samples were investigated as part of the study. The optimum processing conditions were found to be around 0.5 GPa MPC pressure and 1450°C sintering temperature, illustrating maximum density, hardness and minimum shrinkage. High pressure compaction using MPC was found to enhance density with increasing MPC pressure up to 0.9 GPa, and significantly reduce the total shrinkage (about 16% in this case) in the sintered bulks compared to other general processes (about 18%). While sintered samples blended with micro Ti showed presence of microstructural cracks, the samples with 1-2% nano Ti had less or no cracks on them. Overall, the inclusion of nano Ti indicated improvement in mechanical properties of TiO2 nanopowders sintered preforms as opposed to micro Ti-added TiO2.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1473-1477
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect Of The Desorption-Recombination Temperature On The Microstructure And Magnetic Properties Of HDDR Processed Nd-Fe-B Powders
Wpływ temperatury desorpcji-rekombinacji na mikrostrukturę i właściwości magnetyczne proszków Nd-Fe-B przetwarzanych metodą HDDR
Autorzy:
Lee, J.-G.
Cha, H.-R.
Liu, S.
Yu, J.-H.
Baek, Y.-K.
Kwon, H.-W.
Powiązania:
https://bibliotekanauki.pl/articles/353723.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Nd-Fe-B
HDDR
permanent magnet
grain boundary
metoda HDDR
magnes trwały
granica ziarna
Opis:
The effect of the desorption-recombination temperature on the microstructure and magnetic properties of hydrogenation-disproportionation-desorption-recombination (HDDR) processed Nd-Fe-B powders was studied. The NdxB6.4Ga0.3Nb20.2Febal (x=12.5-13.5, at.%) casting alloys were pulverized after homogenizing annealing, and then subjected to HDDR treatment. During the HDDR process, desorption-recombination (DR) reaction was induced at two different temperature, 810°C and 820°C. The higher Nd content resulted in enhanced coercivity of the HDDR powder, and which was attributed to the thicker and more uniform Nd-rich phase along grain boundaries. But this uniform Nd-rich phase induced faster grain growth. The remanence of the powder DR-treated at 820°C is higher than that DR-treated at 810°C. In addition, it was also confirmed that higher DR temperature is much more effective to improve squareness.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1499-1501
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Economic statistical design of variable sampling interval X̅ control chart based on surrogate variable using genetic algorithms
Autorzy:
Lee, T.-H.
Hong, S.-H.
Kwon, H.-M.
Lee, M.
Powiązania:
https://bibliotekanauki.pl/articles/406970.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
economic design
surrogate variable
variable sampling interval
TRISO Fuel
genetic algorithms
Opis:
In many cases, a X̅ control chart based on a performance variable is used in industrial fields. Typically, the control chart monitors the measurements of a performance variable itself. However, if the performance variable is too costly or impossible to measure, and a less expensive surrogate variable is available, the process may be more efficiently controlled using surrogate variables. In this paper, we present a model for the economic statistical design of a VSI (Variable Sampling Interval) X̅ control chart using a surrogate variable that is linearly correlated with the performance variable. We derive the total average profit model from an economic viewpoint and apply the model to a Very High Temperature Reactor (VHTR) nuclear fuel measurement system and derive the optimal result using genetic algorithms. Compared with the control chart based on a performance variable, the proposed model gives a larger expected net income per unit of time in the long-run if the correlation between the performance variable and the surrogate variable is relatively high. The proposed model was confined to the sample mean control chart under the assumption that a single assignable cause occurs according to the Poisson process. However, the model may also be extended to other types of control charts using a single or multiple assignable cause assumptions such as VSS (Variable Sample Size) X̅ control chart, EWMA, CUSUM charts and so on.
Źródło:
Management and Production Engineering Review; 2016, 7, 4; 54-64
2080-8208
2082-1344
Pojawia się w:
Management and Production Engineering Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis and Optimization of Micro Speaker-Box Using a Passive Radiator in Portable Device
Autorzy:
Jiang, Y.-W.
Kwon, J.-H.
Kim, H.-K.
Hwang, S.-M.
Powiązania:
https://bibliotekanauki.pl/articles/176530.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
passive radiator
speaker box
SPL improvement
Sound Pressure Level
Opis:
With the rapid development of multimedia devices such as smart phones and tablet PCs, microspeakers have been recently increasingly used for audio equipment. Improving the acoustic performance of a microspeaker is always a main concern, especially in the low frequency range. To avoid sound cancelation, a microspeaker unit is usually inserted into a speaker box. A passive radiator is also used in speaker boxes to improve the sound performance in the loudspeaker system. However, passive radiators have not been applied into microspeaker system. In this study, a speaker box with a passive radiator was analyzed and optimized to achieve a higher Sound Pressure Level (SPL) in a microspeaker system. The Finite Element Method (FEM), two-degree-of-freedom (DOF) vibration theory, and a plane circular piston sound source were used to study the electromagnetic, vibration, and acoustic characteristics, respectively. Optimization was conducted by changing the mass, stiffness, and size of the passive radiator. Based on the optimized parameters, a new sample was manufactured. The experiment results show that the SPL of the optimized speaker box with a passive radiator is improved by 5 dB at 200 Hz compared with the one without a radiator. The analysis results also matched the experiment results.
Źródło:
Archives of Acoustics; 2017, 42, 4; 753-760
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An analysis on the thermal characteristics according to the viscosity of bearing lubricant and the cooling condition for the high speed motor spindle
Autorzy:
Choi, D. B.
Lee, J. J.
Kim, S. T.
Kwon, H. D.
Kim, C. Y.
Powiązania:
https://bibliotekanauki.pl/articles/1429194.pdf
Data publikacji:
2008
Wydawca:
Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:
high speed motor spindle
thermal displacement cooling condition
lubricant viscosity
Opis:
Thermal displacement of the high speed machine tools has a large influence on machining accuracy. The high speed motor spindle with many heat sources is widely used for the high speed machine tools recently. The important problem in this spindle is to reduce and minimize the thermal effects by motor and bearings. This paper presents the analysis on thermal characteristics for high speed motor spindle system with oil-air lubricated angular contact ceramic ball bearings and built-in motor. An analysis on the thermal characteristics of spindle is performed according to the cooling conditions and the viscosity of bearing lubricants by using finite element method. This results can be applied to the design and manufacturing for the high speed motor spindle.
Źródło:
Journal of Machine Engineering; 2008, 8, 4; 88-98
1895-7595
2391-8071
Pojawia się w:
Journal of Machine Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Study On The Metal Carbide Composite Diffusion Bonding For Mechanical Seal
Badanie łączenia dyfuzyjnego kompozytu metal węglik na mechaniczne uszczelnienie
Autorzy:
Kim, D.-K.
Shon, I.-J.
Song, J.
Ryu, W.-J.
Shin, H.-Ch.
Kwon, E.-Y.
Shin, H.
Kang, S.-J.
Powiązania:
https://bibliotekanauki.pl/articles/356399.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
diffusion bonding
nanostructures
mechanical seal
hard metal
mechanical properties
łączenie
nanostruktura
uszczelnienie mechaniczne
twardy metal
właściwości mechaniczne
Opis:
Mechanical Seal use highly efficient alternative water having a great quantity of an aqueous solution and has an advantage no corrosion brine. Metal Carbide composites have been investigated as potential materials for high temperature structural applications and for application in the processing industry. The existing Mechanical seal material is a highly expensive carbide alloy, and it is difficult to take a price advantage. Therefore the study of replacing body area with inexpensive steel material excluding O-ring and contact area which demands high characteristics is needed. The development of WC-Ni base carbide alloy optimal bonding composition technique was accomplished in this study. To check out the influence of bonding temperature and time, bonding characteristics of sintering temperature was experimented. The bonding statuses of this test specimen were excellent. The hardness of specimen and bonding rate were measured using ultrasound equipment. In this work, Powder of WC (involved VC, Cr), Co and Mo2C mixed by attrition milling for 24hours. Nanostructured WC-27.6wt.%Ni-1.5wt.%Si-0.11wt.%VC-1.1wt.%B4C composite were fabricated at 1190°C by high temperature vacuum furnace. To check out the influence of bonding temperature and time, bonding characteristics of sintering temperature was experimented. Its relative density was about 99.7%. The mechanical properties (hardness and fracture toughness) were 87.2 HRA and 4.2 M·Pam1/2, respectively. The bonding status of this test specimen was excellent and the thickness of bonding layer was 20 ~30§ at 1050 and 1060°C bonding temperature.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1479-1483
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-12 z 12

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