• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.8
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• pp.682-691
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• 2001

Most of radiant floor heating systems are operated in the intermittent heating mode in Korea. The application possibility of predictive suboptimal control for Koran residential house was investigated by computer simulation and experiment. For this study, TRNSYS program was used and an experimental facility consisting of tow rooms ($3\times4.4\times2.8 m$) identical in construction was built. The facility enabled simultaneous comparison of two different control method. And real multi residential hose was investigated. Results showed that outdoor air temperature prediction control was superior to the conventional control for radiant floor heating system operated in the intermittent heating mode. New control system resulted in good thermal environment and les energy consumption.

• Journal of Fisheries and Marine Sciences Education
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• v.28 no.3
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• pp.611-618
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• 2016

A $3{\times}2$ factorial experiment was conducted to investigate effects of water temperature and feeding rate on growth and body composition of olive flounder. Triplicate groups of fish (initial body weight of 118 g) fed a extruded pellet (55% protein and 4708 cal/g) to satiation and at restricted feeding rates of 0.25 and 0.4% body weight per day (BW/d) at the different water temperatures (13 and $18^{\circ}C$) for 9 weeks. Weight gain increased significantly with increase in feeding rates at each temperature. Weight gain of fish fed to satiation was significantly higher at 18 than $13^{\circ}C$, whereas, that of fish fed at 0.25 and 0.4% BW/d were significantly or slightly lower at 18 than $13^{\circ}C$. Feed efficiency and protein efficiency ratio of fish fed to satiation were not significantly different between 13 and $18^{\circ}C$, but those of fish fed at 0.25 and 0.4% BW/d were significantly higher at 13 than $18^{\circ}C$. The major finding of this study is that satiation feeding is efficient for optimal growth and feed efficiency of grower oliver flounder (116-164 g) in suboptimal water temperatures. The maintenance feeding ration which is zero growth performance, were 0.30 and 0.41% BW/day at 13 and $18^{\circ}C$, respectively. In the restricted feeding regime, compromised growth of fish were worsen in higher water temperature ($18^{\circ}C$ vs. $13^{\circ}C$). It might be related to high metabolic rate of fish that spend more energy for maintenance metabolism. Based on these results, we suggest that a satiation feeding regime is recommended for a productive growth of grower olive flounder in the suboptimal temperature.

• ETRI Journal
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• v.37 no.5
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• pp.906-916
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• 2015

High-speed I/O channels require adaptive techniques to optimize the settings for filter tap weights at decision feedback equalization (DFE) read channels to compensate for channel inter-symbol interference (ISI) and crosstalk from multiple adjacent channels. Both ISI and crosstalk tend to vary with channel length, process, and temperature variations. Individually optimizing parameters such as those just mentioned leads to suboptimal solutions. We propose a joint optimization technique for crosstalk cancellation (XTC) at DFE to compensate for both ISI and XTC in high-speed I/O channels. The technique is used to compensate for between 15.7 dB and 19.7 dB of channel loss combined with a variety of crosstalk strengths from $60mV_{p-p}$ to $180mV_{p-p}$ adaptively, where the transmit non-return-to-zero signal amplitude is a constant $500mV_{p-p}$.

• Journal of Microbiology and Biotechnology
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• v.20 no.3
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• pp.615-621
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• 2010

The viability of low-temperature sulfate reduction with hydrogen as electron donor was studied with a bench-scale gas-lift bioreactor (GLB) operated at $9^{\circ}C$. Prior to the GLB experiment, the temperature range of sulfate reduction of the inoculum was assayed. The results of the temperature gradient assay indicated that the inoculum was a psychrotolerant mesophilic enrichment culture that had an optimal temperature for sulfate reduction of $31^{\circ}C$, and minimum and maximum temperatures of $7^{\circ}C$ and $41^{\circ}C$, respectively. In the GLB experiment at $9^{\circ}C$, a sulfate reduction rate of 500-600 mg $l^{-1}d^{-1}$, corresponding to a specific activity of 173 mg ${SO_4}^{2-}g\;VSS^{-1}d^{-1}$, was obtained. The electron flow from the consumed $H_2$-gas to sulfate reduction varied between 27% and 52%, whereas the electron flow to acetate production decreased steadily from 15% to 5%. No methane was produced. Acetate was produced from $CO_2$ and $H_2$ by homoacetogenic bacteria. Acetate supported the growth of some heterotrophic sulfate-reducing bacteria. The sulfate reduction rate in the GLB was limited by the slow biomass growth rate at $9^{\circ}C$ and low biomass retention in the reactor. Nevertheless, this study demonstrated the potential sulfate reduction rate of psychrotolerant sulfate-reducing mesophiles at suboptimal temperature.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.5
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• pp.465-472
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• 1994

To improve the germination performance of rice seeds under suboptimal temperature, osmopriming with PEG-6000 was examined. Optimal PEG-6000 concentration to improve germination was 20% PEG-6000 solution, and rice cultivars used in this experiment were Sinunbongbyeo, Gancheokbyeo, Dongjinbyeo. The water content of seeds after soaking for 60 hours in the PEG solution is similar to that of seeds after soaking for 24 hours in the distilled water. Germination performance of the soaked seeds in the PEG solution was higher than that of the soaked seeds in the distilled water or the control, especially under suboptimal temperatures. Electrical conductivity of the soaked seeds in the PEG solution was lower than that of the soaked seeds in the distilled water or the control, and total dehydrogenase activity of the soaked seeds in the PEG solution was higher than that of the soaked seeds in the distilled water or the control. SDS-PAGE results of soluble protein from the embryos of seeds primed differently showed darker band in the seeds soaked in the PEG solution than the seeds soaked in the distilled water or the control at the 68 KD region. Also, band patterns of peroxidase and esterase of embryos soaked in the PEG solution were darked than that of embryos soaked in the distilled water or the control at the Rf 0.94 and Rf 0.87, respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.2
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• pp.108-111
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• 2000

Osmoconditioning and hardening effects for the seed germination of normal and naturally aged rice seeds were studied through analyzing the total sugars and $\alpha$-amylase activity. The normal seeds which used to have high germination rate accelerated germination with the osmoconditioning at the suboptimal temperature of 17$^{\circ}C$. On the other hand, the aged seeds did not affect germination rate at $25^{\circ}C$, while increased germination rate and accelerated germination a little at 17$^{\circ}C$, Hardening of aged seeds increased germination rate by 10-15% compared with control seeds at both 17 and $25^{\circ}C$ and accelerated germination. Total sugar content and $\alpha$-amylase activity of normal seeds were higher than did aged seeds. The aged seeds with treatment of osmoconditioning and hardening increased total sugar content and $\alpha$--amylase activity, but hardening was more effective than osmoconditioning. The $\alpha$--amylase activity was positively correlated with the total sugar content and germination rate.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.3
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• pp.343-350
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• 2016

The sea cucumber Apostichopus japonicus is a commercially valuable aquaculture species in Korea. Aquaculture species require specific nursery culture conditions to increase survival and growth rates. Sea cucumbers hibernate during the high temperatures of summer and during the low temperatures of winter, and suboptimal temperature conditions decrease sea cucumber growth and survival rates. The natural South Korean environment is very unfavorable for culturing sea cucumber; therefore, developing a recirculating aquaculture system (RAS) capable of breeding and growing sea cucumber year-round is necessary. The aim of this study was to investigate growth performance of juvenile sea cucumber in a RAS. Growth and survival rates of juvenile sea cucumber were high during our 24-week experiment. Sea cucumber survival rates were 87.8-93.3%, and specific growth rates were 0.4689-0.7846.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.7
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• pp.988-995
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• 2003

Physiological parameters were measured on six primiparous, non-pregnant Holstein cows prior to peak lactation over a 3-month summer season in southwestern Taiwan. The objectives were to characterize heat stress-induced change in functionality of mammary gland under natural climates of tropical summer and to establish physiological indices applicable to this environment in referring to this change. Environmental and physiological readings, milk and blood samples were taken at 15:00 h biweekly for totally five time points during the study. Climate readings showed that the afternoon humidex value reached the highest (53.5) around mid summer. Rectal temperature of cows taken simultaneously varied between $38.26^{\circ}C$ and $40.02^{\circ}C$ in parallel to humidex. Milk production declined drastically from 29.2 to 22.2 kg/d the first month entering summer but leveled up at end of the summer season suggesting effects exerted by heat stress rather than stages of lactation. Lactose content decreased linearly (p<0.05) with times in summer, from 4.69 to 4.38%. On the other hand, activity of N-acetylglucosaminidase (NAGase) in milk increased linearly to over two folds (p<0.05) during the same intervals. Elevations of fractional constituent of BSA in whey protein and serum cortisol level were also noticed in the course. Measurement of arteriovenous concentration (A-V) difference across the mammary gland demonstrated net uptake of glucose and net release of urea throughout the study period. The amount of urea released from mammary gland increased (p<0.05) progressively from 1.54 to 7.76 mg/dl during summer. It is concluded that gradual regression of mammary gland occurred along the humid tropical summer season. This regression is likely initiated through elevation of body temperature, which is irreversible above certain point. The increased release of urea from mammary gland during heat stress suggests its potential role as an early indicator of suboptimal mammary function.

• Journal of Environmental Impact Assessment
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• v.21 no.2
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• pp.229-238
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• 2012

This research was to examine the physiochemical factors and the attached diatoms of ecological wetland in Paju from August 2010 to May 2011. As a result of physicohemical water quality assessment, the water temperature did not fluctuate much due to ample riparian vegetation and aquatic plants growing at the site. Due to the effect of Han River Estuary, site 4, 5 and 6 had high electricity conductivity. The BOD concentration was high at site 2, 3, and 4 caused by decrease in water quantity and inflow of polluted water. At all sites, T-N and T-P concentrations ranged from eutrophic to hypertrophic status. At the downstream, the T-N and T-P concentrations decreased by inhabiting aquatic plant. Total of 98 taxa of attached diatoms were found. As for dominant taxa, Achnanthes convergens, A. minutissima, Gomphonema gracile, G. parvulum, Melosira varians, Navicula seminulum, N. minima, N. pseudolanceolata, Nitzschia amphibia, N. palea, Surirella minuta and Synedra ulna var. fragilariodes appeared. The result of biological assessment of water quality rated the sites B(suboptimal)~D(poor) during seasons of low water temperature, Fall and Winter, with DAIpo ranging 24.1~68.2 and TDI of 48.4~85.6. During Spring and Summer, all sites were rated D(poor) with DAIpo lower than or equal to 40, and TDI above or equal to 70. The biological assessment of water quality at the research site showed inferior TDI result compared to that of DAIpo.

• Journal of Bio-Environment Control
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• v.22 no.2
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• pp.87-90
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• 2013

The average annual and winter ambient air temperatures in Korea have risen by $0.7^{\circ}C$ and $1.4^{\circ}C$, respectively, during the last 30 years. Due to climate change, the occurrence of abnormal weather conditions has become more frequent, causing damage to vegetable crops grown in Korea. Hot pepper, chinese cabbage and radish, the three most popular vegetables in Korea, are produced more in the field than in the greenhouse. It has been a trend that the time for field transplanting of seedlings is getting earlier and earlier as the spring temperatures keep rising. Seedlings transplanted too early in the spring take a longer time to resume the normal growth, because they are exposed to suboptimal temperature conditions. This experiment was carried out to figure out the change of cellular tissue of chinese cabbage under the condition of low temperature to provide the information regarding the coming climatic change, on the performance of 'Chunkwang' chinese cabbage during the spring growing season. In our study, plant height, number of leaf, chlorophyll and leaf area was lower at the open field cultivation than heating house treatment after transplanting 50 days. Especially in fresh weight, compared with heating treatment, open field and not heated treatment were notably low with the 1/3 level. Of damage symptoms due to low temperature cabbage leaves about 10 sheets when $-3.0^{\circ}C$ conditions in chinese cabbage was a little bit of water soaking symptoms on the leaves. $-7.4^{\circ}C$ under increasingly severe water soaking symptoms of leaf turns yellow was dry. Microscopy results showed symptoms of $-3.0^{\circ}C$ when the mesophyll cell of palisade tissue and spongy tissue collapse, $-7.4^{\circ}C$ palisade tissue and spongy tissue was completely collapsed. The result of this study suggests that the growers should be cautioned not to transplant their chinese cabbage seedlings too early into the field, and should be re-transplanting or transplanting other plants if chinese cabbage are exposed to suboptimal temperature conditions ($-3.0^{\circ}C$ or $-7.4^{\circ}C$).