• Korean Journal of Ecology and Environment
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• v.40 no.2
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• pp.173-183
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• 2007

The Ministry of Environment plans to introduce the Whole Effluent Toxicity (WET) system in Korea. The WET test is well established in developed countries with recognizing of the limitations of physicochemical analysis method and potential risk of chemicals in water medium. Therefore, it is essential to build the ecotoxicity infrastructure for the induction of WET test. In this study, we extensively collected the domestic and foreign toxicity test methods which employ native test species to Korea. And we suggested that the domestic ecotoxicity test methods with domestic test species in Korea through extracting the range of test conditions. Five domestic fish species selected were Carassiu auratus (Crucian carp), Cyprinus carpio(Common carp), Gasterosteus aculeatus (Three spine stickleback), Misgurnus anguillicaudatus (Oriental weather fish) and Oryzias latipes (Japanese medaka), The toxicity test methods with native test species to Korea were collected from the standard methods (OECD, U.S. EPA, ASTM), government reports, SCI papers and domestic papers. We collected the 32 test methods, and suggested the suitable aquatic toxicity test methods for fish. It is expected that this study could prove a useful information to establish the ecotoxicity test methods with domestic aquatic organisms in Korea henceforth.

• Journal of The Korean Society of Grassland and Forage Science
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• v.29 no.4
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• pp.383-388
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• 2009

This study was conducted to investigate the dry matter intake, weight gain and the required area of grazing pasture for dairy goats. The experimental trials were conducted from April, 2007 to June, 2008 at the animal experimental station in Chungnam National University. The seed mixtures of grazing pasture were composed of orchardgrass (40%) + tall fescue (20%) + perennial ryegrass (10%) + alfalfa (15%) + red clover (15%). The grazing area was $5,000\;m^2$ which was composed of 4 paddocks (average $1,250\;m^2$/plot) and the goats were grazed twelve times by a rotational grazing system. The dairy goats (Saanen) were selected which had nearly the same body weight (average 31.1kg). The average chemical composition of herbage of mixture in grazing periods was crude protein (20.4%), NDF (65.3%) and ADF (31.1%) respectively and the in vitro dry matter digestibility was 68.9%. The average dry matter intake amount per head was 1.253 kg, and the intake amount per body weight was 3.01%. The average body weight gain during the grazing periods (184 days) was 17.4 kg, and the daily gain was 98 g. The required area of grazing pasture was calculated at $467.7\;m^2$ a dairy goat (weight 50 kg basis). This figure, being converted into animal unit (AU), corresponded to approximately 2.14 AU/ha.

• Korean Journal of Optics and Photonics
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• v.17 no.6
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• pp.507-513
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• 2006

In this paper, we propose an improved image encryption and fault-tolerance decryption method using phase wrapping and phase encoding in the frequency domain. To generate an encrypted image, an encrypting key which denotes the product of a phase-encoded virtual image, not an original image, and a random phase image is zero-padded and Fourier transformed and its real-valued data is phase-encoded. The decryption process is simply performed by performing the inverse Fourier transform for multiplication of the encrypted key with the decrypting key, made of the proposed phase wrapping method, in the output plane with a spatial filter. This process has the advantages of solving optical alignment and pixel-to-pixel mapping problems. The proposed method using the virtual image, which does not contain any information from the original image, prevents the possibility of counterfeiting from unauthorized people and also can be used as a current spatial light modulator technology by phase encoding of the real-valued data. Computer simulations show the validity of the encryption scheme and the robustness to noise of the encrypted key or the decryption key in the proposed technique.

• Korean Journal of Remote Sensing
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• v.39 no.5_4
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• pp.1125-1134
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• 2023

Out of the total 17,000 reservoirs in Korea, 13,600 small agricultural reservoirs do not have hydrological measurement facilities, making it difficult to predict water storage volume and appropriate operation. This paper examined univariate and multivariate long short-term memory (LSTM) modeling to predict the storage rate of agricultural reservoirs using remote sensing and artificial intelligence. The univariate LSTM model used only water storage rate as an explanatory variable, and the multivariate LSTM model added n-day accumulative precipitation and date of year (DOY) as explanatory variables. They were trained using eight years data (2013 to 2020) for Idong Reservoir, and the predictions of the daily water storage in 2021 were validated for accuracy assessment. The univariate showed the root-mean square error (RMSE) of 1.04%, 2.52%, and 4.18% for the one, three, and five-day predictions. The multivariate model showed the RMSE 0.98%, 1.95%, and 2.76% for the one, three, and five-day predictions. In addition to the time-series storage rate, DOY and daily and 5-day cumulative precipitation variables were more significant than others for the daily model, which means that the temporal range of the impacts of precipitation on the everyday water storage rate was approximately five days.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.3 s.118
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• pp.248-256
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• 2007

In this paper, we propose a selective DFT spreading method to solve a high PAPR problem in uplink OFDMA system. A selective characteristic is added to the DFT spreading, so the DFT spreading method is mixed with SLM method. However, to minimize increment of computational complexity, differently with common SLM method, our proposed method uses only one DFT spreading block. After DFT, several copy branches are generated by multiplying with each different matrix. This matrix is obtained by linear transforming the each phase rotation in front of DFT block. And it has very lower computational complexity than one DFT process. For simulation, we suppose that the 512 point IFFT is used, the number of effective sub-carrier is 300, the number of allowed sub-carrier to each user's is 1/4 and 1/3 and QPSK modulation is used. From the simulation result, when the number of copy branch is 4, our proposed method has more than about 5.2 dB PAPR reduction effect. It is about 1.8 dB better than common DFT spreading method and 0.95 dB better than common SLM which uses 32 copy branches. And also, when the number of copy branch is 2, it is better than SLM using 32 copy branches. From the comparison, the proposed method has 91.79 % lower complexity than SLM using 32 copy branches in similar PAPR reduction performance. So, we can find a very good performance of our proposed method. Also, we can expect the similar performance when all number of sub-carrier is allocated to one user like the OFDM.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.11
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• pp.5238-5246
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• 2012

This study was done to identify the evaluation of CPSCS for neurocritical patients and provide effective nursing interventions for these patients. Data were collected from medical records of 203 neurocritical patients over 18 years of age who were admitted to the ICU of C University Hospital during the period from January 2008 to May 2009 and from October 2011 to December 2011. Collected data were analyzed through t-test, ANOVA test, Person's correlation analysis, trend analysis, stepwise multiple regression. The average CPSCS score was $112.09{\pm}18.91$ and there was a significant trendency for higher severity to lead to higher CPSCS's scores(survival: J-T:9.795, die: J-T:5.415, p=<.001). The scores of the respective areas follows measurement of vital sign($3.74{\pm}2.15$), monitoring($28.97{\pm}4.31$), activity daily living ($34.99{\pm}3.66$), feeding($.19{\pm}.98$), intravenous infusion ($18.20{\pm}8.27$), treatment/procedure ($16.93{\pm}4.90$), respiratory therapy($8.61{\pm}7.07$). By means of stepwise multiple regression analysis, the intravenous therapy & medication, respiratory therapy, activities of daily living, and monitoring area that contains the model showed a significant (F=2073.963, p<.001), and they explained 98.1% of CPSCS. These findings provide information that is relevant in designing interventions to enhance CPSCS among neurocritical patients in hospital.

• Journal of the Korea Convergence Society
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• v.12 no.8
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• pp.55-60
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• 2021

In order to prepare basic data for research on the protection of emotional workers in Pyeongtaek with the support of Pyeongtaek City, this study conducted a survey centered on 104 counselors classified as emotional laborers. Based on the results of the survey centered on 104 emotional workers, basic research data on the difficulties of emotional workers can be prepared, and protection methods for emotional workers who are currently interested in each local government can be found. As a result of selecting a sample centering on counselors in Pyeongtaek City for a survey on the actual condition of emotional workers, and conducting a survey based on the selected samples, it was found that emotional workers did not find their rights to human rights and were not protected even in the workplace. Currently, a bill to protect emotional workers is being announced, but it is not protected, so it is confirmed that system improvement is necessary. This study focused on 104 items that were significant through pre-processing among the recovered questionnaires. It was analyzed using SPSS, R, and it was confirmed that there is a need for a regulation that can provide an institutional device in Pyeongtaek City. In this study, it is judged that it is necessary to prepare a protective device for emotional workers by selecting more samples corresponding to the occupational group of emotional workers.

• Culinary science and hospitality research
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• v.18 no.1
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• pp.40-53
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• 2012

The quality changes of vegetables including cucumbers, young pumpkins, carrots, radishes, onions by different cooking methods in $90^{\circ}C$ water, 0.5% NaCl solution, 1.0% NaCl solution and $400^{\circ}C$ superheated steam were investigated. The changes in pH of cooked vegetables were increased. Hunter color system values for L(lightness), a(redness) and b(yellowness) of the vegetables cooked in $400^{\circ}C$ supetbeated steam for 30 seconds were less compared with those in $90^{\circ}C$ water, 0.5% NaCl solution and 1.0% NaCl solution. The microbial growth was inhibited very effectively when the vegetables cooked in $400^{\circ}C$ superheated steam for 30 seconds. After cooked in $90^{\circ}C$ water, 0.5% NaCl solution, 1.0% NaCl solution, $400^{\circ}C$ superheated steam, vitamin C content decreased by different ratio depending on cooking methods and vegetable varieties. Based on the results of the quality changes of cooked vegetables, the superheated steam cooking method showed a positive effect on sterilization and maintaining pH, color, hardness of vegetable tissues, vitamin C content. The data obtained from this study could be utilized as basic information for the optimum conditions of superheated steam cooking to develope HMR(Home Meal Replacement).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.10
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• pp.3885-3892
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• 2010

Safety-Critical systems, such as Plant Protection Systems in nuclear power plant, plays a key role that the facilities can be operated without undue risk to the health and safety of public and environment, and those systems shall be designed, fabricated, installed, and tested to quality standards commensurate with the importance of the functions to be performed. Computer-based Instrumentation and Control Systems to perform the safety-critical function have Real Time Operating Systems to control and monitoring the sub-system and executing the application software. The safety-critical Real Time Operating Systems shall be designed, analyzed, tested and evaluated to have capability to maintain a high integrity and quality. However, local nuclear power plants have applied the real time operating systems on safety critical systems through Commercial Grade Item Dedication method, and this is the reason of lack of detailed methodology on assessing the safety of real time operating systems, expecially to the new developed one. This paper presents the methodology and experiences of safety evaluation on safety-critical Real Time Operating Systems based upon design requirements. This paper may useful to develop and evaluate the safety-critical Real Time Operating Systems in other industry to ensure the safety of public and environment.

• Journal of Korea Multimedia Society
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• v.11 no.5
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• pp.685-691
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• 2008

Recently with the rapid evolution of the mobile computing and communication technologies, mobile VOD service becomes increasingly important for wireless mobile users. The VOD service is being widely used in various areas of application, such as education, entertainment and business, because it provides users convenience in easily having access to video information at any time in any places. However, in reality, the mobile system has many difficulties in providing the smooth VOD service owing to frequent transfers and cutoffs of clients. The importance of a technique to transmit broadcasting is being stressed as a method for providing stabler mobile VOD service to a large number of clients. This paper is aimed at showing how to reduce demands for server bandwidth and delay of earlier service through performance analysis by suggesting an effective VOD broadcasting transmission technique through channel division in the mobile atmosphere. Many researches have been made about regular broadcasting techniques in particular. This study divides the methods used for assigning channels which have been decided by the size of segments into a group of regular channels and assistant channels using wireless gap-fillers to provide effective VOD services to a large number of clients at the mobile environment using small bandwidth resources. The regular channels transfer regular streams, while assistant channels repeatedly transfer the first segment to reduce early service delay time to receive regular streams. In this way, the study suggests a technique to reduce server bandwidth demand and early service delay time. Through the proposed technique, the server bandwidth demand could be reduced by more than 30 percent and the study continuously shows reduced early service delay time through conducting performance analysis.