• Journal of Communications and Networks
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• v.18 no.1
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• pp.95-104
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• 2016

Massive multiple-input multiple-output (MIMO) is a promising approach for cellular communication due to its energy efficiency and high achievable data rate. These advantages, however, can be realized only when channel state information (CSI) is available at the transmitter. Since there are many antennas, CSI is too large to feed back without compression. To compress CSI, prior work has applied compressive sensing (CS) techniques and the fact that CSI can be sparsified. The adopted sparsifying bases fail, however, to reflect the spatial correlation and channel conditions or to be feasible in practice. In this paper, we propose a new sparsifying basis that reflects the long-term characteristics of the channel, and needs no change as long as the spatial correlation model does not change. We propose a new reconstruction algorithm for CS, and also suggest dimensionality reduction as a compression method. To feed back compressed CSI in practice, we propose a new codebook for the compressed channel quantization assuming no other-cell interference. Numerical results confirm that the proposed channel feedback mechanisms show better performance in point-to-point (single-user) and point-to-multi-point (multi-user) scenarios.

• The Korean Journal of Mycology
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• v.23 no.4 s.75
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• pp.354-358
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• 1995

A yeast loading biochemical oxygen demand (BOD) sensor was designed and constructed to quickly measure the concentration of biologically assimilable organic substances dissolved in water as BOD values to feed back to the waste water treating processes. The sensitivity of the BOD sensor reached maximum at around pH 7.0 and $30^{\circ}C$ where yeast showed the highest assimilation activity. Biomass also affected the sensor output, and biomass of $ 0.14\;mg/cm^2$ on the dialysis membrane appeared to be the optimum cell mass level. The sensitivity of the sensor depended on the kinds of pollutants and increased considerably when the yeast was preincubated in the solution of respective pollutants before loading on the sensor.

• Journal of the Korean Institute of Intelligent Systems
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• v.6 no.3
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• pp.51-62
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• 1996

Electro sensitive traffic system can not consider passenger car unit, so it causes start up delay time and passenger waiting time. In this paper, it antecedently creates passenger car unit at the bottom intersection using neural network. But, sometimes it can make mistakes due to changes in car weight, car speed, and passing area. Therefore, it consequently reduces the car waiting time and start-up delay time using fuzzy control of feed-back data. Moreover, to prevent spillback, it can adapt control even though upper traffic intersection has a different saturation rate, road length, road slope and road width.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.16 no.3
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• pp.116-120
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• 2006

We have investigated plasma spray coated $Al_2O_3$ layers on Al-60 series substrates for development of wafer electrostatic chuck in semiconductor dry etching system. Samples were prepared without/with cooling bar on backside of samples, at various distances, and with different powder feed rates. There were many cracks and pores in the $Al_2O_3$ layers coated on Al-60 series substrates without cooling bar on the backside of samples. But the cracks and pores were almost disappeared in the $Al_2O_3$ layers on Al-60 series substrates coated with cooling bar on the back side of samples, 15 g/min. powder feed rate and various 60, 70, 80 mm working distances. Then the surface morphology was not changed with various working distances of 60, 70, 80 mm. When the powder feed rate was changed from 15 g/min to 20 g/min, the crack did not appear, but few pores appeared. Also the $Al_2O_3$ layer was coated with many small splats compared with $Al_2O_3$ layer coated with 15 g/min powder feed rate. The deposited rate of $Al_2O_3$ layer was higher when the process was done without cooling bar on the back side of sample than that with cooling bar on the back side of sample.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.9
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• pp.1241-1245
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• 2004

Two separate trials were conducted to determine effects of dietary level of whole flaxseed (WFS; 0, 10 and 15%) on feed intake, weight gain, and carcass yield and quality of Korean Hanwoo cattle. The daily gains of bulls (Trial 1) were not different among treatment groups, but those of cows (Trial 2) fed WFS 15% were higher (p<0.01) than others. Feed intake of both bulls and cows tended to decrease as dietary level of WFS increased. However, feed conversion ratio (feed/gain) of bulls tended to be improved by dietary inclusion of WFS and was significantly improved (p<0.01) in cows by increasing level of WFS. Neither carcass weight nor dressing percentage were affected by WFS level. Back fat thickness of bulls was decreased (p<0.01) by dietary inclusion of WFS and the same trend was observed in cows without statistical significance. Loin-eye area of bulls was not different among treatment groups but was significantly higher (p<0.01) in cows fed WFS. Carcass yield and quality were not improved by WFS addition. The results indicate that WFS is an acceptable fat source in diets of finishing beef cattle to increase energy density without any adverse effects.

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.3
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• pp.26-36
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• 2012

Minimizing the cylinder wear and the consumption rate of cylinder oil in a large two-stroke diesel engine is of great economic importance. A motor-driven cylinder lubricator for Sulzer RT-flex large two-stroke diesel engines developed by authors is in need of mounting a quill system to lubricate cylinder parts for a smooth operation. In order to apply the common-rail lubricating system to the developed cylinder lubricator as the second research stage, the mechanical quill system with a progressively quantitative distributor (M.D.S.) is improved in the electronically controlled quill system with an accumulating distributor (E.D.S.). In this study, the effects of lubricator motor speed, plunger stroke and cylinder back pressure on oil feed rate and inequality rate are experimentally investigated by applying E.D.S. to the developed cylinder lubricator. It is found that the oil feed rate of E.D.S. is higher than that of M.D.S. because of the increase of delivery speed and volume by changing the role of accumulator in the same experimental condition. It can be also shown that, in E.D.S., the inequality rate is decreased a little or hardly unchanged as the cylinder back pressure and plunger stroke is elevated, while the inequality rate increased in M.D.S.. The inequality rates of E.D.S. and M.D.S. are lowered as the lubricator motor speed is increased.

• Corrosion Science and Technology
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• v.18 no.1
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• pp.1-7
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• 2019

To find proper lathe machining parameters for SA182 Grade 304 stainless steel (SS), six kinds of samples with different machining surface states were prepared using a lathe. Surface morphologies and microstructures of near surface deformed layers on different samples were analysed. Surface morphologies and chemical composition of oxide films formed on different samples in simulated primary water with $100{\mu}g/L\;O_2$ at $310^{\circ}C$ were characterized. Results showed that surface roughness was mainly affected by lathe feed. Surface machining caused grain refinement at the top layer. A severely deformed layer with different thicknesses formed on all samples. In addition to high defect density caused by surface deformation, phase transformation, residual stress, and strain also affected the oxidation behaviour of SA182 Grade 304 SS in the test solution. Machining parameters used for # 4 (feed, 0.15 mm/r; back engagement, 2 mm; cutting speed, 114.86 m/min) and # 6 (feed,0.20 mm/r; back engagement, 1 mm; cutting speed, 73.01 m/min) samples were found to be proper for lathe machining of SA182 Grade 304 SS.

• Membrane Journal
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• v.18 no.1
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• pp.26-34
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• 2008

In this study, periodic water-back-flushing using permeate water was performed to minimize membrane fouling and to enhance permeate flux in advanced water treatment system by ceramic microfiltration. We investigated effect of water-back-flushing period (FT) and time (BT), and tried to find the optimal operating conditions. BT was fixed at 3 sec and FT was changed in $30{\sim}120$ sec to inspect effect of FT. Also, FT was fixed at 120 sec and BT was changed as $3{\sim}12$ sec at experiment of BT effect. At both two experiments, TMP was fixed at 1.52 bar, water-back-flushing pressure at 0.98 bar, feed flow rate at 0.5 L/min, and feed water temperature at $20^{\circ}C$. As the result, optimal FT was 30 sec at fixed BT 3 sec in our experimental range. It means that the more frequent back-flushing was the more effective to reduce membrane fouling. However, there were not large effects of FT due to a short BT. Then, increasing BT at fixed FT 120 sec could decrease resistance of membrane fouling ($R_f$) and increase permeate flux (J) and dimensionless permeate flux ($J/J_o$), and the most total permeate volume ($V_T$) could be produced at the maximum BT 12 sec.

• KSBB Journal
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• v.15 no.6
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• pp.649-657
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• 2000

The factors affecting the back-extraction efficiency of Bovine Serum Albumin (BSA, Mw. 65kDa, pl 4.9) solubilized in an AOT reverse micellar solution, prepared by the injection method, to an excess aqueous phase were investigated. In particular, the effects of pH, the types of salts, alcohols added as cosurfactants, and their concentrations in the aqueous phase were examined. Furthermore, by comparing the CD spectra of the back-extracted BSA and the feed BSA, the structural changes of BSA during the extraction process were determined. The addition of 1:1 salt such as KCl or NaCl to the aqueous phase resulted in almost a 100% extraction to the aqueous phase at a pH higher than its isoelectric point pl. This high efficiency of back-extraction might be due to the change in the interactions between the protein and micellar aggregates driven by the added salt. For 1:2 salts like $CaCl_2$ and $MgCl_2$, BSA was back-extracted with lower than 20% extraction efficiency. Maximum extraction efficiencies were attained at about pH=7 and pH=8 for monovalent and divalent salts, respectively. The addition of alcohols as cosurfactants led to an improvement in monovalent and divalent salts, respectively. From the CD spectra of BSA extracted to the aqueous phase, it was observed that denaturation of BSA was not significant. In certain back-extraction conditions, the extracted BSA showed even higher activity than the feed BSA.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.3
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• pp.307-312
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• 2009

The study of candidate genes is an important tool to identify genes associated with economic traits. Three genes were selected to study the association between polymorphism and economic traits and breed of pigs. Growth hormone releasing hormone (GHRH) takes part in growth metabolism and is one of the candidate genes known to be highly associated with economic traits in pigs. Heart fatty acid-binding protein (H-FABP) is related to back fat thickness and intramuscular fat (IMF) content, and myogenin (MYOG) is associated with the amount of growth rate and lean yield in pigs. By PCR-RFLP analysis, the association between the genotypes of the three genes and the average daily gain, back fat thickness, feed conversion, body length and meat percent in 352 pigs (112 Duroc pigs, 132 Landrace pigs and 108 Yorkshire pigs) were analyzed. GHRH polymorphisms showed differences depending on breed (p<0.01) and were associated with meat percent. H-FABP polymorphisms also showed significant differences among breeds and sex (p<0.01), and were highly associated with average daily gain, feed conversion and back fat thickness (p<0.01) and even showed an association with meat percent (p<0.05). However, the MYOG gene showed no significant effect in this study. These results reconfirmed that GHRH and H-FABP are potential major genes or markers for economic traits.