• Proceedings of the Korea Water Resources Association Conference
• /
• 2009.05a
• /
• pp.1112-1116
• /
• 2009

The importance of securing water resources and their efficient management has attracted more attention recently due to water deficit. In water budget analysis, however, evapotranspiration (${\lambda}E$) has been approximated as the residual in the water balance equation or estimated from empirical equations and assumptions. To minimize the uncertainties in these estimates, it is necessary to directly measure ${\lambda}E$. In this study, using the eddy covariance technique, we have measured ${\lambda}E$ in a mixed forest in the Seolmacheon catchment in Korea from September 2007 to December 2008. During the growing season (May - July), ${\lambda}E$ in this mixed forest averaged about 2.2 mm $d^{-1}$, whereas it was on average 0.5 mm $d^{-1}$ during the non-growing season in winter. The annual total ${\lambda}E$ in 2008 was 581 mm $y^{-1}$, which is about 1/3 of the annual precipitation of 1997 mm. Despite the differences in the amount and frequency of precipitation, the accumulated ${\lambda}E$ during the overlapping period (i.e., September to December) for 2007 and 2008 was both ${\sim}$ 110 mm, showing virtually no difference. The omega factor, which is a measure of decoupling between forest and the atmosphere, was on average 0.5, indicating that the contributions of equilibrium ${\lambda}E$ and imposed ${\lambda}E$ to the total ${\lambda}E$ were about the same. The results suggest that ${\lambda}E$in this mixed forest was controlled by various factors such as net radiation, vapor pressure deficit, and canopy conductance. In this study, based on the direct measurements of ${\lambda}E$, we have quantified the relative contribution of ${\lambda}E$in the water balance of a mixed forest in the Seolmacheon catchment. In combination with runoff data, the information on ${\lambda}E$ would greatly enhance the reliability of water budget analysis in this catchment.

• Journal of Korea Water Resources Association
• /
• v.49 no.12
• /
• pp.1027-1034
• /
• 2016

One of the most important purpose of multi-purpose reservoir is storing a large amount of water for utilization in a dry season. However, multi-purpose reservoirs that were constructed according to the limited hydrologic information available at the time of construction may encounter problems such as decreased water inflow due to climate change and an inability to cope with a water shortage. To solve these problems, in 2015, the Ministry of Land, Infrastructure and Transport suggested a revised water supply standard in case of water shortage for reservoirs. However, the revised standard has not been sufficiently discussed to determine its effectiveness. In addition, multi-purpose reservoirs in South Korea have secured and stored water for emergencies, but there is currently no way to utilize the stored water. Determining how to utilize the stored water effectively may be a useful method for preparing drought. Therefore, this article discusses the revised water supply standard as it relates to a water shortage in reservoirs and a method of utilizing the water stored for emergencies in multi-purpose reservoirs. The options for utilizing the water storage were evaluated using a water shortage safety degree index, and the results showed that the options may slightly and limitedly increase the water supply capacity. However, the evaluation also showed that a complex application of two options may overcome the exisiting problem and to supply water more effectively.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.11
• /
• pp.672-682
• /
• 2020

The Korea Nowadays, which is research on digital twin technology for efficient operation in various industrial/manufacturing sites, is being actively conducted, and gradual depletion of fossil fuels and environmental pollution issues require new renewable/eco-friendly power generation methods, such as wave power plants. In wave power generation, however, which generates electricity from the energy of waves, it is very important to understand and predict the amount of power generation and operational efficiency factors, such as breakdown, because these are closely related by wave energy with high variability. Therefore, it is necessary to derive a meaningful correlation between highly volatile data, such as wave height data and sensor data in an oscillating water column (OWC) chamber. Secondly, the methodological study, which can predict the desired information, should be conducted by learning the prediction situation with the extracted data based on the derived correlation. This study designed a workflow-based training model using a machine learning framework to predict the pressure of the OWC. In addition, the validity of the pressure prediction analysis was verified through a verification and evaluation dataset using an IoT sensor data to enable smart operation and maintenance with the digital twin of the wave generation system.

• Journal of KIISE:Software and Applications
• /
• v.35 no.4
• /
• pp.207-218
• /
• 2008

With the growth of the Internet, multimedia streaming becomes an important means to deliver video contents over the Internet and the amount of the streaming multimedia contents is also getting increased. However, it becomes difficult to guarantee the quality of service in real-time over the IP network environment with instantaneously varying bandwidth. In this paper, we propose an optimal adaptation framework for streaming contents over the Internet in the sense that the perceptual quality of the multi-angie content with multiple visual objects is maximized given the constraints such as available bandwidth and transcoding cost. In the multi-angle video service framework, the user can select his/her preferred alternate views among the given multiple video streams captured at different view angles for a same event. This enhanced experience often entails streaming problems in real-time over the network, such as instantaneous bandwidth changes in the Internet. In order to cope with this problem, we assume that multi-angle video contents are encoded at different bitrates and the appropriate video streams are then selected or transcoded for delivery to meet such bandwidth constraints. For the user selective consumption of the various bitstreams in the multi-angle video service, the bitstream in each angle can be encoded in various bitrate, and the user can select a sub-bitrstream in the given bitrstreams or transcode the corresponding content in order to deliver the optimally adapted video contents to the instantaneously changing network condition. Therefore, we define the transcoding cost which means the time taken for transcoding the video stream and formulate a unified optimization framework which maximizes the perceptual quality of the multiple video objects in the given constraints such as the transcoding cost and the network bandwidth. Finally, we present plenty of the experimental results to show the effectiveness of the proposed method.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.12 no.1
• /
• pp.207-215
• /
• 2011

This study was about the relation of 129 differently stressed male college students's on or off-line contact behavior to out-eating places. We researched the subjects's obesity degree such as body fat percentage, body mass index, stress condition, and contact behavior to out-eating places. Subjects's average age was 20, height 174.9cm. More stress they felt, heavier their body weight was and more obese. 37.1% of Strongly stressed group, 28.8% of medium and 25% of normal stressed group felt severe depression. As the result of pearson correlation, stress condition was positively related with body weight, obese degree, body mass index(BMI) and exercise time. Body weight was positively related with obeses degree, BMI, and the amount of smoking and drinks. Strongly stressed group used more internet to search the information about out-eating places, they had more experience to search the homepage of out-eating places than other groups significantly. Strongly stressed group cared more about the sanity of out-eating places where they ate. and they were interested in various experiences than other groups. Strongly stressed group felt the tasty was the most important satisfying factor significantly and visited the out-eating place that satisfied them again than other groups.

• The KIPS Transactions:PartC
• /
• v.12C no.1 s.97
• /
• pp.121-128
• /
• 2005

Tho existing TCP(Transmission Control Protocol) is known to be unsuitable for a network with the characteristics of high RDP(Bandwidth-Delay Product) because of the fixed small or large buffer size at the TCP sender and receiver. Thus, some trial cases of adjusting the buffer sizes automatically with respect to network condition have been proposed to improve the end-to-end TCP throughput. ATBT(Automatic TCP fluffer Tuning) attempts to assure the buffer size of TCP sender according to its current congestion window size but the ATBT assumes that the buffer size of TCP receiver is maximum value that operating system defines. In DRS(Dynamic Right Sizing), by estimating the TCP arrival data of two times the amount TCP data received previously, the TCP receiver simply reserves the buffer size for the next arrival, accordingly. However, we do not need to reserve exactly two times of buffer size because of the possibility of TCP segment loss. We propose an efficient TCP buffer tuning technique(called TBT-PLR: TCP buffer tuning algorithm based on packet loss ratio) since we adopt the ATBT mechanism and the TBT-PLR mechanism for the TCP sender and the TCP receiver, respectively. For the purpose of testing the actual TCP performance, we implemented our TBT-PLR by modifying the linux kernel version 2.4.18 and evaluated the TCP performance by comparing TBT-PLR with the TCP schemes of the fixed buffer size. As a result, more balanced usage among TCP connections was obtained.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.10 no.1
• /
• pp.75-86
• /
• 2002

This study was performed to investigate situation of livestock manure generated from Kangwon-do and to evaluate its composting probability. The scale of livesrock-farming is bigger and bigger in Korea. Regulation based on the heads of livestock is slightly different from that based on livestock-farming household. So it is needed ro evaluate regulations for livestock head and livestock-farming household. Composting and liquid fertilization were thought to be appropriate technologies to the trearment of Korean cattle and pig manures, respectively. Generation quantity of pig manure was the greatest among pig, Korean cattle, cow and chicken manures. Pig manure generated the greatest amounts of BOD in Kangwon-do. Pig manure contained nitrogen, Korean cattle manure contained $K_2O$, and chicken and pig manures contained $P_2O_5$ in great amount. Alternative ratio of livestock manure to crops-fertilizer was 51% for nitrogen, 38% for $K_2O$, and 34% for $P_2O_5$.

• Journal of Internet Computing and Services
• /
• v.18 no.1
• /
• pp.65-75
• /
• 2017

The Detection Model is the model to find the result of a certain purpose using artificial intelligent, data mining, intelligent algorithms In Cyber Security, it usually uses to detect intrusion, malwares, cyber incident, and attacks etc. There are an amount of unlabeled data that are collected in a real environment such as security data. Since the most of data are not defined the class labels, it is difficult to know type of data. Therefore, the label determination process is required to detect and analysis with accuracy. In this paper, we proposed a KDFL(K-means and D-S Fusion based Labeling) method using D-S inference and k-means(unsupervised) algorithms to decide label of data records by fusion, and a detection model architecture using a proposed labeling method. A proposed method has shown better performance on detection rate, accuracy, F1-measure index than other methods. In addition, since it has shown the improved results in error rate, we have verified good performance of our proposed method.

• The Journal of the Korea Contents Association
• /
• v.15 no.6
• /
• pp.297-302
• /
• 2015

High-energy medical linear accelerator on the dose to the thyroid cancer during radiotherapy were evaluated using optical stimulation luminescence dosimeters(OSLD) using. Scattered's influence in the case of 3D-CRT 25.4 mSv, 28.8 mSv, 31.3 mSv, 26.5 mSv, 27.4 mSv 5 times with an average 27.9 mSv, in the IMRT 46.8 mSv, 43.2 mSv, 42.3 mSv, 41.5 mSv, 44.1 mSv to five times the average of 43.6 was the result of mSv. In the case of light neutron dosimetry results 3D-CRT 3 mSv, 3 mSv, 3.4 mSv, 3.5 mSv, 3.1 mSv to five times the average 3.2 mSv, in the IMRT 5.1 mSv, 4.8 mSv, 4.2 mSv, 4.8 mSv, 4.9 mSv, to five times the average of 4.7 was the result of mSv. Both parties and the light scattered neutrons were significantly appreciated compared to IMRT 3D-CRT. Treatment of cancer using radiation workers, as in this study, and that a significant amount of scattered rays in the adjacent normal tissues during radiation therapy using energy assessment to influence by fully aware of this information is necessary for the exposure reduction efforts the feed.

• Economic and Environmental Geology
• /
• v.42 no.4
• /
• pp.343-356
• /
• 2009

SCS method was applied to make the assessments of direct runoff according to land use changes in Jeju island. Land uses were obtained from 5 year-period remote sensing time series data from 1975 to 2000 which are provided by Water Management Information System (WAMIS). Hydrologic soil groups were categorized based on soil series of National Academy of Agricultural Sciences (NAAS), and permeable geologic structures such as Sumgol, Gotzawal and so on. The land uses of Jeju island are obviously characterized by urban-agricultural areas increases, and forest areas decrease. According to land use changes, curve number (CN) for Jeju island was consistently increased from 65.3 in 1975 to 69.6 in 2000. From 1975 to 2000, the amount of direct runoff and ratios increased due to CN changes. When the rainfall data in 1995 was applied to each year, the direct runoff amounts were $299.0{\sim}351.6\;mm$, and runoff ratios were $15.1{\sim}17.7%$. In the case of the application of the rainfall data in 2000, the direct runoff amounts were $136.9{\sim}161.5\;mm$, and runoff ratios were $9.7{\sim}11.5%$. Since direct runoff can be closely related to groundwater recharge and sustainable groundwater yield, the groundwater influence caused by land use changes or district exploitations should be considered for the reasonable water management and development in Jeju island.