• Journal of Korea Water Resources Association
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• v.42 no.3
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• pp.213-225
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• 2009

A stationary Markov chain model is a stochastic process with the Markov property. Having the Markov property means that, given the present state, future states are independent of the past states. The Markov chain model has been widely used for water resources design as a main tool. A main assumption of the stationary Markov model is that statistical properties remain the same for all times. Hence, the stationary Markov chain model basically can not consider the changes of mean or variance. In this regard, a primary objective of this study is to develop a model which is able to make use of exogenous variables. The regression based link functions are employed to dynamically update model parameters given the exogenous variables, and the model parameters are estimated by canonical correlation analysis. The proposed model is applied to daily rainfall series at Seoul station having 46 years data from 1961 to 2006. The model shows a capability to reproduce daily and seasonal characteristics simultaneously. Therefore, the proposed model can be used as a short or mid-term prediction tool if elaborate GCM forecasts are used as a predictor. Also, the nonstationary Markov chain model can be applied to climate change studies if GCM based climate change scenarios are provided as inputs.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.2
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• pp.208-213
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• 2007

The objective of the experiment was to determine the optimum cultural [moisture levels (55, 60 and 70%), days of fermentation (7, 14 and 21), temperature (25 and $35^{\circ}C$) of incubation)] and nutritional parameters (urea addition (0 and 2%) and variable levels of single super phosphate (0.25 and 0.50% SSP)) for bio-processing of the mustard (Brassica campestris) straw (MS) under solid-state fermentation (SSF) system. The performance of SSF was assessed in terms of favorable changes in cell wall constituents, protein content and in vitro DM digestibility of the MS. Sorghum based inoculum (seed culture) of Ganoderma lucidum to treat the MS was prepared. The 50 g DM of MS taken in autoclavable polypropylene bags was mixed with a pre-calculated amount of water and the particular nutrient in the straw to attained the desired levels of water and nutrient concentration in the substrate. A significant progressive increase in biodegradation of DM (p<0.001), NDF (p<0.01) and ADF (p<0.05) was observed with increasing levels of moisture. Among the cell wall constituents the loss of ADF fraction was greatest compared to that of NDF. The loss of DM increased progressively as the fermentation proceeded and maximum DM losses occurred at 28 days after incubation. The protein content of the treated MS samples increased linearly up to the day $21^{th}$ of the incubation and thereafter declined at day $28^{th}$, whereas the improvement in in vitro DM digestibility were apparent only up to the day $14^{th}$ of the incubation under SSF and there after it declined. The acid detergent lignin (ADL) degradation was slower during the first 7 days of SSF and thereafter increased progressively and maximum ADL losses were observed at the day $28^{th}$ of the SSF. The biodegradation of DM and ADL was not affected by the variation in incubation temperature. Addition of urea was found to have inhibitory effect on fungal growth. The effect of both the levels (0.25 and 0.50) of SSP addition in the substrate, on DM, NDF, ADF, cellulose and ADL biodegradation was similar. Similarly, the protein content and the in vitro DM digestibility remain unaffected affected due to variable levels of the SSP inclusion in the substrate. From the results it may be concluded that the incubation of MS with 60 percent moisture for 21 days at $35^{\circ}C$ with 0.25 percent SSP was most suitable for MS treatment with Ganoderma lucidum. Maximum delignification, enrichment in the protein content and improvement in in vitro DM digestibility were achieved by adopting this protocol of bioprocessing of MS.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.40 no.3
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• pp.67-73
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• 2022

This study tracked the changing process of unregistered private house gardens by using the form at the time of the construction of gardens as the prototype of each garden, investigated the spatial value of the garden, and discussed the historical spatial value of unregistered private house gardens in terms of inheritance and change of traditional gardens. To this end, targeting on unregistered private house gardens in Gangwon-do, which are in danger of preserving their gardens due to the recent increase in the number of designated cultural heritage dismantled, the patterns of unregistered private house gardens, their characteristics and values were identified through the spatial change of the garden, and the following results were derived. First, the unregistered private house gardens were able to inherit and maintain the form of a traditional garden, being located in a clan village. The garden space was divided by the influence of Confucian philosophy, and the components of the garden, tree species and planting methods appeared differently. In other words, the use of garden components according to the status hierarchy appeared. Second, space reduction was continuously confirmed at four target sites. The reduced spaces are garden spaces, and part of the garden was attributed to the state due to the building of new road and environmental improvement project. The reduced spaces are garden spaces, and part of the garden was attributed to the state due to the new road and environmental improvement project. Third, eight old big trees over 100 years old were identified in three of the four target sites, and the garden components such as stone water tanks, quickset doors, and ponds were commonly identified in Korea, China, and Japan during the Joseon Dynasty, inheriting the historicity of the traditional garden.

• Korean Journal of Ecology and Environment
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• v.40 no.3
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• pp.468-480
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• 2007

The urbanization is altering the hydrology, water quality, channel form of waterway and changing the composition of biological communities in the aquatic ecosystem. Recently, towns grew bigger by the drift of large numbers of people and the medium and small leather and dyeing industries around the Pocheon and Youngpyeong streams. The discharges of sewage were increased by them. The UII (urban intensity index) was 85 (st. P-3) and 91 (st. P-6) in the Pocheon stream and about 20 in the Youngpyeong stream. A total 141 taxa of epilithic diatoms which were composed of 2 order, 8 family, 30 genera. Dominant species were Navicula saprophila, N. subminuscula, Nitzschia palea, Gomphonema pseudoaugur in the Pocheon stream and Achnanthes alteragracillima, A. convergens, A. minutissima, N. minima, N. fonticola, N. frustulum and Cymbella minuta var. silesiaca in the Youngpyeong stream. It Showed the different composition of dominant species by the urbanization near two streams. In the relationships between UII and environmental factors such as EC, BOD, COD, TN, TP and DAIpo, UII showed the high relations $(r^2>0.8)$. It was the difference of organic pollution according to urbanization. It therefore, was higher the relative abundance and more the numbers of saprophilous taxa in the Pocheon stream than the Youngpyeong stream. The water quality of two streams by biological indicators(DAIpo) was polysaprobic state(st. P-3, P-4, P-5) in the Pocheon stream and was oligosaprobic (Y-1), mesosaprobic (Y-2, 3) and polysaprobic state (Y-4) in the Youngpyeong stream during the investigation periods.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.406-406
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• 2016

To get high efficiency n-type crystalline silicon solar cells, passivation is one of the key factor. Tunnel oxide (SiO2) reduce surface recombination as a passivation layer and it does not constrict the majority carrier flow. In this work, the passivation quality enhanced by different chemical solution such as HNO3, H2SO4:H2O2 and DI-water to make thin tunnel oxide layer on n-type crystalline silicon wafer and changes of characteristics by subsequent annealing process and firing process after phosphorus doped amorphous silicon (a-Si:H) deposition. The tunneling of carrier through oxide layer is checked through I-V measurement when the voltage is from -1 V to 1 V and interface state density also be calculated about $1{\times}1012cm-2eV-1$ using MIS (Metal-Insulator-Semiconductor) structure . Tunnel oxide produced by 68 wt% HNO3 for 5 min on $100^{\circ}C$, H2SO4:H2O2 for 5 min on $100^{\circ}C$ and DI-water for 60 min on $95^{\circ}C$. The oxide layer is measured thickness about 1.4~2.2 nm by spectral ellipsometry (SE) and properties as passivation layer by QSSPC (Quasi-Steady-state Photo Conductance). Tunnel oxide layer is capped with phosphorus doped amorphous silicon on both sides and additional annealing process improve lifetime from $3.25{\mu}s$ to $397{\mu}s$ and implied Voc from 544 mV to 690 mV after P-doped a-Si deposition, respectively. It will be expected that amorphous silicon is changed to poly silicon phase. Furthermore, lifetime and implied Voc were recovered by forming gas annealing (FGA) after firing process from $192{\mu}s$ to $786{\mu}s$. It is shown that the tunnel oxide layer is thermally stable.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.15 no.4
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• pp.271-282
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• 1982

The browning development, mainly through the Maillard reaction, occurring in the dried fish meat products during storage causes reduction of the nutritional value due to the loss of the essential amino acid such as available lysine as well as off -flavor resulting in the deterioration of the food quality thus shortening the shelflife. In the work, the changes in the amount of available lysine, extractable nitrogenous compounds (nonprotein-N, amino-N, trimethylamine oxide, trimethylamine, and free lysine) and development of browning were measured to assess the relationship between the shelflife and the quality loss in dried filefish under the steady state conditions (35,45, and $55^{\circ}C;a_{w}'s$ of 0.44 0.52, 0.65 and 0.75 at each temperature) and fluctuating temperature condition of $35/55^{\circ}C$ will. alternating 7 day periods at each water activity. The results indicated that the amount of available lysine and extractable nitrogenous compounds except TMA decreased rapidly with increasing temperatures and water activities while the rate of available lysine and extractable nitrogenous compounds must be involved in the initial stage of brown pigment formation. The available lysine loss of the dried filefish products stored under the fluctuating temperature conditions was greater than that stored under its fixed mean temperature, $45^{\circ}C$. The activation energies for lysine loss obtained from the Arrhenius plot ranged 6.9 to 4.4 Kcal/mol and $Q_{10}$ values at $40^{\circ}C$ were 1.4 to 1.2. The values for browning were 15.7 to 14.4 Kcal/mol and 2.2 to 2.0 respectively. Shelf-life, defined as the time to reach 0.15 O. D./g solid or the limit of off-color deterioration by browning reaction, was extented longer than the halflife of Iysine loss, actually corresponding $75\%$ loss of available lysine. This suggested that the halflife of lysine loss might not be adequate to assess the shelf-life of the food system with high potential of protein, nonproteinous nitrogen compounds, and lipids.

• Journal of Korea Water Resources Association
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• v.49 no.3
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• pp.241-252
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• 2016

In this study, the characteristics of flow and bed changes with variation of space and length of serial spur dikes were investigated with 2 dimensional numerical simulation. Upstream spur dike was affected by flow and made a role as a single spur dike. As time increased, local scouring was developed around outside of spur dike, and migrated upstream. The aggradation of the bed at the back of spur-dike was made at the initial stage of experiment and numerical modelling. However, the aggradation of the bed was increased in the downstream area. The scour whole around a spur dike upstream was not deep as the Dimensionless spur-dike interval (b) of the dike increased. The depth of scour hole was nearly constant at the dynamic equilibrium state. The dimensionless scour depth ($y_s/H$) increased with L/b. The spur dike downstream had the characteristics of single spur dike as the L/b was larger than 10. However, the spur dike downstream was affected by the dike upstream as the L/b was less than 4, and the bed of the upstream in the spur dike was aggradated and the effects of the serial spur dikes on the bed decreased.

• Korean Journal of Ecology and Environment
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• v.33 no.3 s.91
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• pp.187-196
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• 2000

This paper describes a simple method that uses differences among Carlson's (1977) trophic state index (TSI) values based on total phosphorus (TP), chlorophyll a (CHL) and Secchi depth (SD) to draw inferences regarding the factors that are limiting to phytoplankton growth and the composition of lake seston. Examples are provided regarding seasonal and spatial patterns in a large subtropical lake (Lake Okeechobee, Florida, USA) and inter- and intra-lake variations from a multilake data set developed from published studies. Once an investigator has collected routine water quality data and established TSI values based on TP, CHL, and SD, a number of inferences can be made. Additional information can be provided where it also is possible to calculate a TSI based on total nitrogen (TN). Where TSI (CHL)<>TSI (SD), light attenuating particles are large (large filaments or colonies of algae), and the phytoplankton may be limited by zooplankton grazing. Other limiting conditions are inferred by different relationships between the TSI values. Results of this study indicate that the analysis is quite robust, and that it generally gives good agreement with conclusions based on more direct methods (e.g., nutrientaddition bioassays, zooplankton size data, zooplankton removal experiments). The TSI approach, when validated periodically with these more costly and time-intensive methods, provides an effective, low cost method for tracking long-term changes in pelagic structure and function with potential value in monitoring lake ecology and responses to management.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.3
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• pp.249-256
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• 1986

The carp (Cyprinus carpio) used in the experiment were hatched in the spring this year and reared to 5.96g($4.84{\sim}6.55g$) in mean weight in a nursery pond at Daeyon fish farm, Pusan, Korea. The sample fish were exposed to different conditions of total ammonia (TA-N) concentrations 10, 20 and 30ppm and pH 6.5, 7.0, 7.5 and 8.0 at water temperatures 20, 25 and $30^{\circ}C$ for 24, 48 and 72 hours. After the procedure, the gill, liver and kidney of the fish were examined histopathologically. In this experiment, with the rise of water temperature, increase of pH and ammonia concentration, and the extension of exposure time the three organs showed the tendency of apparent abnormal changes such as hypertrophy and necrosis in their tissues. At $20^{\circ}C$ of water temperature gill tissue did not show any abnormality regardless of the change of pH at 10 ppm of ammonia concentration for 24 hours of exposure, but beyond the conditions given above, there occurred hypertrophy and the epithelium of gill lamellae was detached. The detach of gill lamellae epithelium initiated from the proximal part of the gill lamellae then gradually spread toward the uppermost tip. The heavier vacuolation of the liver was observed with the rise of water temperature and pH, and such morbid state in the liver was considered to be the result of edema in the liver tissue. The kidney showed no damage to the renal tubule epithelium at pH 6.5, but it was damaged at pH 8.0 when exposed to 30 ppm ammonia at $20^{\circ}C$ for 24 hours.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.7 no.2
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• pp.41-51
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• 1974

A study of the sanitary quality of Pacific oysters (Crassostrea gigas) and growing waters associated with raft culture in Burley Lagoon, Washington was conducted. The study was sponsored by the Agency for International Development of the U.S. Department of State. The results obtained in this study are as follows: The average values of temperature, salinity and turbidity in the water showed that the values of bottom sample were slightly higher than top samples. The difference was about $0.3^{\circ}C$ for temperature, $0.5\%_{\circ}$ for salinity and 0.1 JTU for turbidity. The changes of temperature and salinity by tide generally followed the tide cycle pattern. Sanitary indicator microorganism concentrations in top water were generally higher than those in bottom water. In general, the levels of mean coliform and fecal coliform MPN's varied inversely with tide level indicating that the sources of these groups of microorganisms are the fresh water streams flowing into the estuary. The $35^{\circ}C$ plate counts were more stable at different tide levels. Mean values of coliform and fecal coliform MPN's in oysters demonstrated that levels in top oysters were generally higher than those in bottom oysters. However, mean values of $35^{\circ}C$ Plate count in oysters did not show this pattern. The mean levels of both coliform and fecal coliform MPN's in oysters also correlated inversely with tidal level. The accumulation ratios of oysters obtained during the study period ranged from 8.6 to 19.7 for mean coliform MPN and 16.9 to 44.3 for fecal coliform MPN. According to the results obtained from present study, one suggestion could be of considerable importance for the sanitary operation in hanging culture of pacific oysters. The results indicate that harvest of the oysters at high tide would result in lower levels of indicator organisms in the shellfish.