• Journal of Korean Society on Water Environment
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• v.36 no.6
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• pp.489-499
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• 2020

Effective science-based management of the basin water resources requires an understanding of the characteristics of the streams, such as the baseflow discharge. In this study, the base flow was estimated in the two watersheds with the least artificial factors among the Nakdong River watersheds, as determined using the chemical hydrograph separation technique. The 16-year (2004-2019) discontinuous observed stream flow and electrical conductivity data in the Total Maximum Daily Load (TMDL) monitoring network were extended to continuous daily data using the TANK model and the 7-parameter log-linear model combined with the minimum variance unbiased estimator. The annual base flows at the upper Namgang Dam basin and the upper Nakdong River basin were both analyzed to be about 56% of the total annual flow. The monthly base flow ratio showed a high monthly deviation, as it was found to be higher than 0.9 in the dry season and about 0.46 in the rainy season. This is in line with the prevailing common sense notion that in winter, most of the stream flow is base flow, due to the characteristics of the dry season winter in Korea. It is expected that the chemical-based hydrological separation technique involving TANK and the 7-parameter log-linear models used in this study can help quantify the base flow required for systematic watershed water environment management.

• Journal of Soil and Groundwater Environment
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• v.25 no.4
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• pp.98-105
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• 2020

In this study, the concentrations of some of the important ionic contaminants in groundwaters of national monitoring network in Korea were identified, and their correlation to nitrate concentration was investigated. Approximately 80% of the groundwater samples were found to be as Ca2+-(Cl-+NO3-) type groundwater with the concentration ranges [minimum to maximum values, median (mg/L)] of Ca2+[0.1~228.2, 19.7], Mg2+[0.1~53.2, 5.1], K+[0.1~50.8, 1.9], Na+[1.5~130.5, 18.1], NO3--N[0.1~73.4, 9.3], NH4+-N[0.0~53.9, 0.3], Cl-[3.1~482.6, 24.0], and SO42-[2.8~101.6, 7.0]. The prevalence of Ca2+-(Cl-+NO3-) type suggest that the composition of groundwaters were greatly influcenced by chemical fertilizers and animal manure, Correlation analyses indicated threre was positive correlation between NO3--N concentration and ionic species including Cl-, Ca2+, Mg2+, and Na+. In particular, the correlation was strongest for Cl- and NO3--N, suggesting that groundwaters largely impacted by agricultural and livestock breeding activities tend to contain high levels of Cl-.

• Journal of the Korea Convergence Society
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• v.12 no.2
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• pp.21-28
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• 2021

In this study, we propose a deep learning-based NILM technique using actual measured power data for 5 kinds of home appliances and verify its effectiveness. For about 3 weeks, the active power of the central power measuring device and five kinds of home appliances (refrigerator, induction, TV, washing machine, air cleaner) was individually measured. The preprocessing method of the measured data was introduced, and characteristics of each household appliance were analyzed through spectogram analysis. The characteristics of each household appliance are organized into a learning data set. All the power data measured by the central power measuring device and 5 kinds of home appliances were time-series mapping, and training was performed using a LSTM neural network, which is excellent for time series data prediction. An algorithm that can disaggregate five types of energies using only the power data of the main central power measuring device is proposed.

• Journal of Advanced Navigation Technology
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• v.24 no.6
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• pp.593-600
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• 2020

The equipment for marine IoT service have to overcome the effect of seawater. Furthermore, the free floating transmitter in seawater will be less affected by the seawater environment. The results of the design and fabrication of antenna, which is embedded in buoy, are shown in this research. The proposed antenna is used to supervise the states of fishing gears in monitoring system for real-name system of electric fishing gear. The selected frequency band of the proposed antenna is 920 MHz, and PCB pattern type is selected for subminiature and light weight. It is confirmed that RF characteristics is more degraded, however, the radiation is gradually upward as the contact surface of buoy with seawater is more broaden through the simulation results. That is, the RF performance of the proposed antenna is more deteriorated but beam radiation characteristics is more suited the marine IoT, the seawater effect is more increased. It is expected that the proposed antenna will contribute the implementation of IoT network based on low power wide area (LPWA) when the degradation of RF performance will be settled.

• Korean Journal of Plant Resources
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• v.34 no.6
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• pp.575-599
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• 2021

The edible roots of radish (Raphanus sativus L.) are consumed worldwide. For characterization and evaluation of the agronomic traits and health-promoting chemicals in radish germplasms, new germplasm breeding materials need to be identified. The objectives of this study were to evaluate the phenotypic traits and glucosinolate contents of radish roots from 110 germplasms, by analyzing correlations between 10 quantitative phenotypic traits and the individual and total contents of five glucosinolates. Phenotypic characterization was performed based on descriptors from the UPOV and IBPGR, and glucosinolate contents were analyzed using liquid chromatography-tandem mass spectrometry in multiple reaction monitoring mode (MRM). Regarding the phenotypic traits, a significant correlation between leaf length and root weight was observed. Glucoraphasatin was the main glucosinolate, accounting for an average of 71% of the total glucosinolates in the germplasms; moreover, its content was significantly correlated with that of glucoerucin, its precursor. Principal component analysis indicated that the 110 germplasms could be divided into five groups based on their glucosinolate contents. High levels of free-radical scavenging activity (DPPH) were observed in red radishes. These results shed light on the beneficial traits that could be targeted by breeders, and could also promote diet diversification by demonstrating the health benefits of various germplasms.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.1
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• pp.94-103
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• 2022

As a large amount of data generated by sensors or devices at the manufacturing site is transmitted to the server or client, problems arise in network processing time delay and storage resource cost increase. To solve this problem, considering the manufacturing site, where real-time responsiveness and non-disruptive processes are essential, QRC (Quotient Remainder Compression) and BL_beta compression algorithms that enable real-time and lossless compression were applied to actual manufacturing site sensor data for the first time. As a result of the experiment, BL_beta had a higher compression rate than QRC. As a result of experimenting with the same data by slightly adjusting the data size of QRC, the compression rate of the QRC algorithm with the adjusted data size was 35.48% and 20.3% higher than the existing QRC and BL_beta compression algorithms.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.4
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• pp.556-561
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• 2022

In this paper, we present a block media communication (BMC) system which employs powerline communication to the equipments used in the welding process for ship-assembly and uses metal block as a communication medium. Inductive couplers are installed on digital feeder and pin jig. Information signal is added to the current generated by the welding gun, and applied to the block. When the welding operation starts, information generated in the field is transmitted to the monitoring server in real-time. The field test on the BMC system confirms that the transmitted data are correctly received at the server. Since the proposed system can be built without any changes to the existing welding process, it is helpful to increase competitiveness of the shipbuilding industry through smart factory of shipyards. It is also possible to quickly respond to emergency situations that may occur to workers in an electromagnetic wave shielding environment or a closed space, the effect of preventing industrial accidents will be great.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.32 no.3
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• pp.527-545
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• 2022

In order to effectively detect APT attacks performed by well-organized adversaries, we implemented a system to detect attacks by reconstructing attack chains of APT attacks. Our attack chain-based APT attack detection system consists of 'events collection and indexing' part which collects various events generated from hosts and network monitoring tools, 'unit attack detection' part which detects unit-level attacks defined in MITRE ATT&CK^® techniques, and 'attack chain reconstruction' part which reconstructs attack chains by performing causality analysis based on provenance graphs. To evaluate our system, we implemented a test-bed and conducted several simulated attack scenarios provided by MITRE ATT&CK Evaluation program. As a result of the experiment, we were able to confirm that our system effectively reconstructed the attack chains for the simulated attack scenarios. Using the system implemented in this study, rather than to understand attacks as fragmentary parts, it will be possible to understand and respond to attacks from the perspective of progress of attacks.

• Journal of Korean Society on Water Environment
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• v.37 no.6
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• pp.531-538
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• 2021

In this study, the TOC in six estuarine reservoirs in the West Sea (Ganwol, Namyang, Daeho, Bunam, Sapkyo, and Asan) was estimated using optically-active water quality factors by the water environment monitoring network. First, specification data and land use maps of each estuarine reservoir were collected. Subsequently, water quality data from 2013 to 2020 were collected. The data comprised of 11 parameters: pH, dissolved oxygen, BOD, COD, suspended solids (SS), total nitrogen, total phosphorus, water temperature, electrical conductivity, total coliforms, and chlorophyll-a (Chl-a). The TOC in the estuarine reservoirs was 4.9~7.0 mg/L, with the highest TOC of 7.0 mg/L observed at the Namyang reservoir, which has a low shape coefficient and high drainage density. The correlation of TOC with water quality factors was also analyzed, and the correlation coefficients of Chl-a and SS were 0.28 and 0.19, respectively, while the correlation coefficients of these factors in the Namyang reservoir were 0.42 and 0.27, respectively. To improve the estimation of TOC using Chl-a and SS, the TOC was averaged in 5 mg/L units, and Chl-a and SS were averaged. Correlation analysis was then performed and the R² of Chl-a-TOC was 0.73. The R² of SS-TOC was 0.73 with a non-linear relationship. TOC had a significant non-linear relationship with Chl-a and SS. However, the relationship should be assessed in terms of the spatial and temporal variations to construct a reliable remote sensing system.

• Nuclear Engineering and Technology
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• v.54 no.2
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• pp.608-616
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• 2022

Power peaking factors (PPF) is an important parameter for safe and efficient reactor operation. There are several methods to calculate the PPF at TRIGA research reactors such as MCNP and TRIGLAV codes. However, these methods are time-consuming and required high specifications of a computer system. To overcome these limitations, artificial intelligence was introduced for parameter prediction. Previous studies applied the neural network method to predict the PPF, but the publications using the ANFIS method are not well developed yet. In this paper, the prediction of PPF using the ANFIS was conducted. Two input variables, control rod position, and neutron flux were collected while the PPF was calculated using TRIGLAV code as the data output. These input-output datasets were used for ANFIS model generation, training, and testing. In this study, four ANFIS model with two types of input space partitioning methods shows good predictive performances with R² values in the range of 96%-97%, reveals the strong relationship between the predicted and actual PPF values. The RMSE calculated also near zero. From this statistical analysis, it is proven that the ANFIS could predict the PPF accurately and can be used as an alternative method to develop a real-time monitoring system at TRIGA research reactors.