• Korean Journal of Fisheries and Aquatic Sciences
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• v.26 no.4
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• pp.380-391
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• 1993

The experimental study was made to propose the treatment method of wastewater in the high-density fish culture system. The BOD to COD ratios of effluents were almost same to 0.65 in the eel-farm, but were various in the farm rearing together with tilapia etc. A BOD rate curve of the eel-farm effluent could be described mathematically by the equation, $BODu=14.1(1-10^{-0.222t})+30.9(1-10^{-0.035(t-8)})$. Nitrification in Biological Fluidized Bed(BFB) system to treat the fish-farm wastewater could be reduce ammonium level up to $65{\sim}79\%$ when ammonium loading rates were between 0.014 and 0.075g $NH_4/g$ BVS-day. Nitrification efficiency was decreased by organic matters in the wastewater when ammonium loading was low(0.014 g $NH_4/g$ BVS-day). T-N removal ratios were decreased to increase loading in denitrification process, because of low C/N ratio. Based on much higher biological mass concentrations, BFB system takes many advantages of a practical viewpoint, such as stability of treatment efficiency and reduction of necessary site area for the facility, as compared with conventional treatment systems.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.5
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• pp.459-468
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• 1986

This study was attempted to process low-sodium salt fermented small shrimp as substitutes for traditional high-sodium salt fermented one which has widely been favored and consumed in Korea. Low-salt fermented small shrimp was prepared with $4\%$ sodium chloride and $4\%$ potassium chloride, and various additives such as $0.5\%$ lactic acid, $6\%$ sorbitol and $4\%$ ethylalcohol extract of red pepper as preservatives and flavor enhancers. And the changes of taste compounds, volatile compounds and fatty acid composition in low-salt fermented small shrimp were analyzed and compared with those of conventional $20\%$ sodium salt fermented one during the fermentation of 120 days at $25{\pm}3^{\circ}C$. The most favorable taste for fermented small shrimp were reached at 60 days of fermentation. Judging from sensory evaluation, little difference of taste was detected between the low-salt fermented small shrimp and high-sodium salt fermented one. The principal taste compounds in fermented small shrimp were free amino acids, and betaine and nucleotides and their related compounds played an assistant role. The major amino acids in fermented small shrimp were glutamic acid, leucine, proline, glycine, lysine and aspartic acid. The major fatty acids in fermented small shrimp samples were 16:0, 20:5, 22:6, 16:1 and 18:1, and unsaturated fatty acids decreased slightly while saturated fatty acids increased during fermentation. At 60 days of fermentation 8 kinds of volatile fatty acids (acetic acid, propionic acid, isobutyric acid, butyric acid, isovaleric acid, valeric acid, isocarproic acid, carproic acid), 6 kinds of carbonyl compounds (ethanal, propanal, 2-methylpropanal, 3-methylbutanal, pentanal, 2-methylpentanal), and 3 kinds of volatile amines (methylamine, trimethylamine, isopropylamine) were identified.

• Journal of Intelligence and Information Systems
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• v.17 no.4
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• pp.241-254
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• 2011

Financial time-series forecasting is one of the most important issues because it is essential for the risk management of financial institutions. Therefore, researchers have tried to forecast financial time-series using various data mining techniques such as regression, artificial neural networks, decision trees, k-nearest neighbor etc. Recently, support vector machines (SVMs) are popularly applied to this research area because they have advantages that they don't require huge training data and have low possibility of overfitting. However, a user must determine several design factors by heuristics in order to use SVM. For example, the selection of appropriate kernel function and its parameters and proper feature subset selection are major design factors of SVM. Other than these factors, the proper selection of instance subset may also improve the forecasting performance of SVM by eliminating irrelevant and distorting training instances. Nonetheless, there have been few studies that have applied instance selection to SVM, especially in the domain of stock market prediction. Instance selection tries to choose proper instance subsets from original training data. It may be considered as a method of knowledge refinement and it maintains the instance-base. This study proposes the novel instance selection algorithm for SVMs. The proposed technique in this study uses genetic algorithm (GA) to optimize instance selection process with parameter optimization simultaneously. We call the model as ISVM (SVM with Instance selection) in this study. Experiments on stock market data are implemented using ISVM. In this study, the GA searches for optimal or near-optimal values of kernel parameters and relevant instances for SVMs. This study needs two sets of parameters in chromosomes in GA setting : The codes for kernel parameters and for instance selection. For the controlling parameters of the GA search, the population size is set at 50 organisms and the value of the crossover rate is set at 0.7 while the mutation rate is 0.1. As the stopping condition, 50 generations are permitted. The application data used in this study consists of technical indicators and the direction of change in the daily Korea stock price index (KOSPI). The total number of samples is 2218 trading days. We separate the whole data into three subsets as training, test, hold-out data set. The number of data in each subset is 1056, 581, 581 respectively. This study compares ISVM to several comparative models including logistic regression (logit), backpropagation neural networks (ANN), nearest neighbor (1-NN), conventional SVM (SVM) and SVM with the optimized parameters (PSVM). In especial, PSVM uses optimized kernel parameters by the genetic algorithm. The experimental results show that ISVM outperforms 1-NN by 15.32%, ANN by 6.89%, Logit and SVM by 5.34%, and PSVM by 4.82% for the holdout data. For ISVM, only 556 data from 1056 original training data are used to produce the result. In addition, the two-sample test for proportions is used to examine whether ISVM significantly outperforms other comparative models. The results indicate that ISVM outperforms ANN and 1-NN at the 1% statistical significance level. In addition, ISVM performs better than Logit, SVM and PSVM at the 5% statistical significance level.

• Journal of Chest Surgery
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• v.30 no.7
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• pp.677-685
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• 1997

Thromboelastography(TEG) is the unique measure that gives rapid information about the whole clotting process. Simplifying the diagnosis of coagulopathy during operations, TEG can provide an adequate therapy for postoperative bleeding. Remarkable improvement in hemostasis after cardiopulmonary bypass(CPB) has been achieved by the treatment with proteinase inhibitor aprotinin, but the hemostatic mechanism of aprotinin during CPB is still unclear. This study was designed to evaluate the effects of aprotinin on coagulation system during CPB by using TEG. Forty patients who underwent CPB were divided into two groups: aprotinin(2u 106 kallikrein inhibition units, as a single dose into the cardiopulmonary bypass priming solution) treatment group(male 14, female 8, mean age=50.Byears) and no aprotinin treatment(control) group(male 10, female 8, mean age=53.4 years). TEG, activated clotting time, prothrombin time, activated partial thromboplastin time, platelet counts, fibrinogen an (ibrinogen degradation product(FDP) concentrations were checked before and after CPB(30 minutes after neutralization of heparin effect by protamine sulfate). There was no significant difference in other conventional coagulation tests of two groups except postcardiopulmonary bypass FDP concentration in control group, which was significantly increased compared to that in aprotinin group(p<0.05). In TEG variables of both groups, clot formation time(K) and alpha $angle(\alpha^{\circ})$ were significantly increased and decreased, respectively, after CPB(p<0.05), but fibrinolytic index(LYS60) was not changed during CPB. In aprotinin group, reaction time(R) was decreased significantly after CPB(p<0.05) but maximum amplitude(MA) was not changed(p>0.05). On the contrary, R was not changed markedly but MA was decreased significantly in control group after CPB(p<0.05). This result shows that main change in coagulation system during CPB is not hyperfibrinolysis but cecrease in clot strength by platelet dys unction, and the main effect of aprotinin during cardiopulmonary bypass is the maintenance of clot strength to the pre-CPB level by the preservation of platelet function.

• Journal of the Korean Vacuum Society
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• v.15 no.4
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• pp.395-403
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• 2006

It is known that $MgAl_2O_4$ has higher resistance to moisture than MgO, in humid ambient MgO is chemically unstable. It reacts very easily with moisture in the air. In this study, the characteristic of $MgAl_2O_4$ and $MgAl_2O_4/MgO$ layers as dielectric protection layers for AC- PDP (Plasma Display Panel) have been investigated and analysed in comparison for conventional MgO layers. MgO and $MgAl_2O_4$ films both with a thickness of $1000\AA$ and $MgAl_2O_4/MgO$ film with a thickness of $200/800\AA$ were grown on the Cu substrates using the electron beam evaporation. $1000\AA$ thick aluminium layers were deposited on the protective layers in order to avoid the charging effect of $Ga^+$ ion beam while the focused ion beam(FIB) is being used. We obtained sputtering yieds for the MgO, $MgAl_2O_4$ and $MgAl_2O_4/MgO$ films using the FIB system. $MgAl_2O_4/MgO$ protective layers have been found th show $24{\sim}30%$ lower sputtering yield values from 0.244 up to 0.357 than MgO layers with the values from 0.364 up to 0.449 for irradiated $Ga^+$ ion beam with energies ranged from 10 kV to 14 kV. And $MgAl_2O_4$ layers have been found to show lowest sputtering yield values from 0.88 up to 0.109. Secondary electron emission coefficient(g) using the ${\gamma}$- FIB. $MgAl_2O_4/MgO$ and MgO have been found to have similar g values from 0.09 up to 0.12 for indicated $Ne^+$ ion with energies ranged from 50 V to 200 V. Observed images for the surfaces of MgO and $MgAl_2O_4/MgO$ protective layers, after discharge degradation process for 72 hours by SEM and AFM. It is found that $MgAl_2O_4/MgO$ protective layer has superior hardness and degradation resistance properties to MgO protective layer.

• Radiation Oncology Journal
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• v.23 no.3
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• pp.169-175
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• 2005

Purpose: Although computed tomography (CT) simulators are commonly used in radiation therapy department, many Institution still use conventional CT for treatments. In this study the setup errors that occur during simulation, CT scan (diagnostic CT scanner), and treatment were evaluated for the twenty one breast cancer patients. Materials and Methods: Errors were determined by calculating the differences in isocenter location, SSD, CLD, and locations of surgical clips implanted during surgery. The anatomic structures on simulation film and DRR image were compared to determine the movement of isocenter between simulation and CT scan. The isocetner point determined from the radio-opaque wires placed on patient's surface during CT scan was moved to new position if there was anatomic mismatch between the two images Results: In 7/21 patients, anatomic structures on DRR Image were different from the simulation Image thus new isocenter points were placed for treatment planning. The standard deviations of the diagnostic CT setup errors relative to the simulator setup in lateral, longitudinal, and anterior-posterior directions were 2.3, 1.6, and 1.6 mm, respectively. The average variation and standard deviation of SSD from AP field were 1.9 mm and 2.3 mm and from tangential fields were 2.8 mm and 3.7 mm. The variation of the CLD for the 21 patients ranged from 0 to 6 mm between simulation and DRR and 0 to 5 mm between simulation and treatment. The group systematic errors analyzed based on clip locations were 1.7 mm in lateral direction, 2.1 mm in AP direction, and 1.7 mm in SI direction. Conclusion: These results represent that there was no significant differences when SSD, CLD, clips' locations and isocenter locations were considered. Therefore, it is concluded that when a diagnostic CT scanner is used to acquire an image, the set-up variation is acceptable compared to using CT simulator for the treatment of breast cancer. However, the patient has to be positioned with care during CT scan in order to reduce the setup error between simulation and CT scan.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.11 s.353
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• pp.58-68
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• 2006

This work proposes a 10b 250MS/s $1.8mm^2$ 85mW 0.13um CMOS A/D Converter (ADC) for high-performance integrated systems such as next-generation DTV and WLAN simultaneously requiring low voltage, low power, and small area at high speed. The proposed 3-stage pipeline ADC minimizes chip area and power dissipation at the target resolution and sampling rate. The input SHA maintains 10b resolution with either gate-bootstrapped sampling switches or nominal CMOS sampling switches. The SHA and two MDACs based on a conventional 2-stage amplifier employ optimized trans-conductance ratios of two amplifier stages to achieve the required DC gain, bandwidth, and phase margin. The proposed signal insensitive 3-D fully symmetric capacitor layout reduces the device mismatch of two MDACs. The low-noise on-chip current and voltage references can choose optional off-chip voltage references. The prototype ADC is implemented in a 0.13um 1P8M CMOS process. The measured DNL and INL are within 0.24LSB and 0.35LSB while the ADC shows a maximum SNDR of 54dB and 48dB and a maximum SFDR of 67dB and 61dB at 200MS/s and 250MS/s, respectively. The ADC with an active die area of $1.8mm^2$ consumes 85mW at 250MS/s at a 1.2V supply.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.1
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• pp.102-109
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• 2003

The purpose of this study was to evaluate the linear polymerization shrinkage(%) and microhardness of composite resin(Z-100, 3M, USA) according to 2-step light curing method. Conventional light curing unit(Curing Light 2500, 3M USA) and 2-step light curing unit(Elipar Highlight, ESPE, Germany) were used as light source. The strain gauge method was used for determination of polymerization shrinkage(%). Samples were divided by 3 groups according to light curing methods (Group I : $450mW/cm^2$, 40sec, Group II : $650mW/cm^2$, 40sec, Group III : $150mW/cm^2$, 10sec & $650mW/cm^2$, 30sec). Preparations of acrylic molds were followed by filling and curing. Strain gauges attached to each sample were connected to a strainmeter. Measurements were recorded at each second for the total of 10 minutes including the periods of light application. And microhardness of each group after 24hours from light irradiation were measured. Obtained data were analyzed statistically using Ore-way ANOVA and/or Scheffe test. The results of the present study can be summarized as follows: 1. Composite resin in acrylic molds showed the initial expansion at the early phase of polymerization. This was followed by the contraction with the rapid increase in volume during the first 60 seconds and gradually diminished as curing process continued. 2. The lowest linear polymerization shrinkage(%) was found in group III followed by group I, II during the measuring periods. 3. Group III using 2-step curing method showed statistically significant reduction of linear polymerization shrinkage(%) compared with group I, II at 1 minute and 10 minutes from light irradiation(p<0.05). 4. The microhardness values of each group not revealed significant difference.

• Geophysics and Geophysical Exploration
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• v.11 no.1
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• pp.1-14
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• 2008

We present a method for interpreting seismic records with arrivals and waveforms having characteristics which could be generated by extremely inhomogeneous velocity structures, such as non-typical oceanic crust, decollement at subduction zones, and seamounts in oceanic regions, by comparing them with synthetic waveforms. Recent extensive refraction and wide-angle reflection surveys in oceanic regions have provided us with a huge number of high-resolution and high-quality seismic records containing characteristic arrivals and waveforms, besides first arrivals and major reflected phases such as PmP. Some characteristic waveforms, with significant later reflected phases or anomalous amplitude decay with offset distance, are difficult to interpret using only a conventional interpretation method such as the traveltime tomographic inversion method. We find the best process for investigating such characteristic phases is to use an interactive interpretation method to compare observed data with synthetic waveforms, and calculate raypaths and traveltimes. This approach enables us to construct a reasonable structural model that includes all of the major characteristics of the observed waveforms. We present results here with some actual observed examples that might be of great help in the interpretation of such problematic phases. Our approach to the analysis of waveform characteristics is endorsed as an innovative method for constructing high-resolution and high-quality crustal structure models, not only in oceanic regions, but also in the continental regions.

• Korean Journal of Food Science and Technology
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• v.52 no.1
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• pp.1-10
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• 2020

The present study identified the restrictions on the use of sous-vide products in the Korean HMR market for small and medium-sized manufacturing companies. A detailed literature review revealed that the HMR market in Korea is close to saturation. Notably, the technologically advanced products produced using sous-vide seem to display significant potential to overcome market saturation. The sous-vide method differs from conventional cooking techniques and is characterized by maintenance of food texture along with flavor enhancement. However, due to the unfamiliarity of the manufacturers with this method and the unclear food safety regulations, mass food manufacturing companies do not agree on using this method; hence, sous-vide production is usually undertaken by small/medium sized companies catering primarily through online marketing portals. This study highlights the various restrictions to the implementation of sous-vide production, and discusses several practical implications of sous-vide production that would help users of this technique enter the HMR market.