• Korean Journal of Remote Sensing
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• v.27 no.5
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• pp.573-586
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• 2011

The MTF(modulation transfer function) is one of parameters to evaluate the performance of imaging systems. Also, it can be used to restore information that is lost by a harsh space environment (radioactivity, extreme cold/heat condition and electromagnetic field etc.), atmospheric effects and falloff of system performance etc. This paper evaluated the MTF values of images taken by DubaiSat-1 satellite which was launched in 2009 by EIAST(Emirates Institute for Advanced Science and Technology) and Satrec Initiative. Generally, the MTF was assessed using various methods such as a point source method and a knife-edge method. This paper used the slanted-edge method. The slantededge method is the ISO 12233 standard for the MTF measurement of electronic still-picture cameras. The method is adapted to estimate the MTF values of line-scanning telescopes. After assessing the MTF, we performed the MTF compensation by generating a MTF convolution kernel based on the PSF(point spread function) with image denoising to enhance the image quality.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.3
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• pp.379-385
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• 2017

Objective: This study was to examine in vivo digestibility, nitrogen balance and ruminal fermentation of tamarind (Tamarind indica) kernel powder extract residue (TKPER) compared to soybean products and by-products in wethers. Methods: Four wethers with initial body weight (BW) of $51.6{\pm}5.5kg$ were assigned in a $4{\times}4$ Latin square design to investigate nutritional characteristics of TKPER, dry heat soybean (SB), dry soybean curd residue (SBCR) and soybean meal (SBM) feeding with ryegrass straw (R) at a ratio of 1:1 at 2% of BW in dry matter (DM) on a daily basis. Results: The digestibility of DM, crude protein, and ether extract (EE) of TKPER-R diet were 57.0%, 87.0%, and 86.0%, respectively. Higher non-fiber carbohydrates digestibility was observed in TKPER-R diet (83.2%) than in SB-R diet (73.9%, p<0.05). Wethers fed the TKPER-R diet had lower retention of nitrogen (N) and ruminal ammonia nitrogen ($NH_3-N$) contents at 4 h after feeding than those fed the SBM-R diet (p<0.05), which had values similar to the SB-R or SBCR-R diet. The TKPER feeding had higher propionate (C3) and lower butyrate content, as well as lower acetate to propionate ratio (C2:C3) in rumen fluid than SBM feeding at 4 h after feeding (p<0.05). Conclusion: TKPER did not bring any side effect to the wethers although it was lack of fiber, and could be used as a high protein and energy ingredient in concentrate with appropriate roughage to meet the fiber requirement for ruminants.

• Korean Journal of Agricultural and Forest Meteorology
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• v.17 no.2
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• pp.156-164
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• 2015

High temperature stress would affect rice production in the future as heat wave is expected to occur frequently under climate change conditions. The objective of this study was to obtain rudimentary information to assess the impact of heat stress on rice yield and its yield component in Korea. Two rice cultivars "Hwaseongbyeo" (Japonica) and "Dasanbyeo" (Tongil-type) were grown at different nitrogen fertilization levels in two seasons. These cultivars were grown in 1/5000a Wagner pot placed within four plastic houses where temperature was controlled at ambient, ambient$+1.5^{\circ}C$, ambient$+3^{\circ}C$ and ambient$+5^{\circ}C$ throughout the rice growing season in Suwon ($37^{\circ}16^{\prime}N$, $128^{\circ}59^{\prime}E$), Korea. The degree of temperature change affected grain yield whereas the level of nitrogen had little impact on grain yield. The number of panicle per pot and spikelet per panicle were not significantly different among temperature treatments in both cultivars tested. In contrast, 1000-grain weight and ripened grain ratio were decreased significantly under the treatments raising the air temperature to the level of $5.0^{\circ}C$ and $1.5^{\circ}C$ above the ambient air temperature in Dasanbyeo and Hwaseongbyeo, respectively. Reduction of 1000-grain weight and ripened grain ratio under the temperature treatments of $3.0^{\circ}C$ and $5.0^{\circ}C$ above the ambient air temperature resulted in significantly less grain yield for Dasanbyeo and Hwaseongbyeo, respectively. The greater sensitivity of grain yield to temperature increase in Dasanbyeo was attributable to the sharp decrease of 1000-grain weight and ripened grain ratio with the temperature rise above $23^{\circ}C$ during ripening period. On the other hand, Hwaseongbyeo had little variation of them in the temperature range of $23-27^{\circ}C$. These results suggested that grain yield would decrease under future climate conditions due to grain weight decreased by shorter grain filling period as well as the ripened grain ratio reduced by spikelet sterility and early abortion of rice kernel development. Thus, it would be essential to use cultivars tolerant to heat stress for climate change adaptation, which merits further studies for developing varieties that have traits to avoid spikelet sterility and early abortion of rice kernel, e.g., early morning flowering, under heat wave.

• Journal of applied mathematics & informatics
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• v.12 no.1_2
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• pp.81-105
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• 2003

This paper deals with the very interesting problem about the influence of piecewise smooth boundary conditions on the distribution of the eigenvalues of the negative Laplacian in R$^3$. The asymptotic expansion of the trace of the wave operator (equation omitted) for small ｜t｜ and i=√-1, where (equation omitted) are the eigenvalues of the negative Laplacian (equation omitted) in the (x$^1$, x$^2$, x$^3$)-space, is studied for an annular vibrating membrane $\Omega$ in R$^3$together with its smooth inner boundary surface S$_1$and its smooth outer boundary surface S$_2$. In the present paper, a finite number of Dirichlet, Neumann and Robin boundary conditions on the piecewise smooth components (equation omitted)(i = 1,...,m) of S$_1$and on the piecewise smooth components (equation omitted)(i = m +1,...,n) of S$_2$such that S$_1$= (equation omitted) and S$_2$= (equation omitted) are considered. The basic problem is to extract information on the geometry of the annular vibrating membrane $\Omega$ from complete knowledge of its eigenvalues by analysing the asymptotic expansions of the spectral function (equation omitted) for small ｜t｜.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.4
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• pp.1-11
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• 2004

Combustion and fuel distribution characteristics of heavy duty engine with the liquid phase LPG injection(LPLI) were studied in a single cylinder engine, Swirl ratio were varied between 1.2, 2.3, and 3.4 following Ricardo swirl number(Rs) definition, Rs=2.3 showed the best results with lower cycle-by-cycle variation and shorter burning duration in the lean region while strong swirl(Rs=3.4) made these worse for combustion enhancement. Excessive swirl resulted in reverse effects due to high heat transfer and initial flame kernel quenching. Fuel injection timings were categorized with open valve injection(OVI) and closed valve injection(CVI). Open valve injection showed shorter combustion duration and extended lean limit. The formation of rich mixture in the spark plug vicinity was achieved by open valve injection. With higher swirl strength(Rs=3.4) and open valve injection, the cloud of fuel followed the flow direction and the radial air/fuel mixing was limited by strong swirl flow. It was expected that axial stratification was maintained with open-valve injection if the radial component of the swirling motion was stronger than the axial components. The axial fuel stratification and concentration were sensitive to fuel injection timing in case of Rs=3.4 while those were relatively independent of the injection timing in case of Rs=2.3.

• Nuclear Engineering and Technology
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• v.39 no.5
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• pp.603-616
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• 2007

Roy Huddle, having invented the coated particle in Harwell 1957, stated in the early 1970s that we know now everything about particles and coatings and should be going over to deal with other problems. This was on the occasion of the Dragon fuel performance information meeting London 1973: How wrong a genius be! It took until 1978 that really good particles were made in Germany, then during the Japanese HTTR production in the 1990s and finally the Chinese 2000-2001 campaign for HTR-10. Here, we present a review of history and present status. Today, good fuel is measured by different standards from the seventies: where $9*10^{-4}$ initial free heavy metal fraction was typical for early AVR carbide fuel and $3*10^{-4}$ initial free heavy metal fraction was acceptable for oxide fuel in THTR, we insist on values more than an order of magnitude below this value today. Half a percent of particle failure at the end-of-irradiation, another ancient standard, is not even acceptable today, even for the most severe accidents. While legislation and licensing has not changed, one of the reasons we insist on these improvements is the preference for passive systems rather than active controls of earlier times. After renewed HTGR interest, we are reporting about the start of new or reactivated coated particle work in several parts of the world, considering the aspects of designs/ traditional and new materials, manufacturing technologies/ quality control quality assurance, irradiation and accident performance, modeling and performance predictions, and fuel cycle aspects and spent fuel treatment. In very general terms, the coated particle should be strong, reliable, retentive, and affordable. These properties have to be quantified and will be eventually optimized for a specific application system. Results obtained so far indicate that the same particle can be used for steam cycle applications with $700-750^{\circ}C$ helium coolant gas exit, for gas turbine applications at $850-900^{\circ}C$ and for process heat/hydrogen generation applications with $950^{\circ}C$ outlet temperatures. There is a clear set of standards for modem high quality fuel in terms of low levels of heavy metal contamination, manufacture-induced particle defects during fuel body and fuel element making, irradiation/accident induced particle failures and limits on fission product release from intact particles. While gas-cooled reactor design is still open-ended with blocks for the prismatic and spherical fuel elements for the pebble-bed design, there is near worldwide agreement on high quality fuel: a $500{\mu}m$ diameter $UO_2$ kernel of 10% enrichment is surrounded by a $100{\mu}m$ thick sacrificial buffer layer to be followed by a dense inner pyrocarbon layer, a high quality silicon carbide layer of $35{\mu}m$ thickness and theoretical density and another outer pyrocarbon layer. Good performance has been demonstrated both under operational and under accident conditions, i.e. to 10% FIMA and maximum $1600^{\circ}C$ afterwards. And it is the wide-ranging demonstration experience that makes this particle superior. Recommendations are made for further work: 1. Generation of data for presently manufactured materials, e.g. SiC strength and strength distribution, PyC creep and shrinkage and many more material data sets. 2. Renewed start of irradiation and accident testing of modem coated particle fuel. 3. Analysis of existing and newly created data with a view to demonstrate satisfactory performance at burnups beyond 10% FIMA and complete fission product retention even in accidents that go beyond $1600^{\circ}C$ for a short period of time. This work should proceed at both national and international level.