• Journal of Korea Water Resources Association
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• v.43 no.6
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• pp.543-557
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• 2010

The effects of the selection for sediment transport equations and advection-diffusion equations according to different sediment transport modes on the modeling results of bed changes were analyzed using the CCHE2D and compared with field data in this paper. The most suitable sediment transport equation and sediment transport mode for advection-diffusion equation were suggested for the upstream approached channel of the Nakdong River Estuary Barrage. The bed changes simulated by the Engelund and Hansen formula were very small in the modeling case for the low and high flow discharges compared with the case of the Ackers and White formula. Also, the numerical modeling with the actual hydraulic event in 2002 presents that the bed change result with the bed load transport type for advection-diffusion equation was close to the field measurement more than the suspended load type.

• Korean Journal of Clinical Pharmacy
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• v.29 no.3
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• pp.209-214
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• 2019

Doxycycline is frequently prescribed to treat urogenital infections or acne vulgaris. A 39-year-old man was prescribed doxycycline as a treatment for his skin infection. He took each tablet on an empty stomach in the morning, and just before going to bed with insufficient water. After taking the prescribed medication for approximately 3 weeks, he was diagnosed with esophageal ulcer. He had not experienced these symptoms before, and the drug label says that doxycycline rarely causes esophageal ulcer. After discontinuing the medication, the symptoms disappeared. Using the World Health Organization-Uppsala Monitoring Center criteria, the causality for doxycycline-induced esophageal ulcer was evaluated as "possible." Additionally, using the Naranjo scale and Korean causality assessment algorithm (Ver. 2), the causality was evaluated as "probable." Previous reports have stated that most patients who took doxycycline with insufficient water just before going to bed or in the supine position developed esophageal ulcer. Therefore, all patients taking doxycycline must be provided with detailed instructions about the appropriate administration methods.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.11A
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• pp.1059-1067
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• 2006

AODV(Ad-hoc On-demand Distance Vector) routing protocol was devised for use of mobile nodes in Ad-hoc network. When we use the AODV routing protocol in Ad-hoc networks with high mobility, disturbance of optimized route path and link break occur. In order to solve the shortcomings, this paper proposes a new routing protocol in which new routing control messages are added to the existing AODV. The proposed protocol minimizes link break and transmission delay while is able to secure the optimized route path constantly in changes of network topology The performance of the proposed routing protocol was evaluated by using us2 network simulator. The actual Ad-hoc network test bed provides us the most reliable experimental data for Ad-hoc networks. In order to support this experimental environment, the dissertation also developed an efficient embedded system on which AODV routing protocol, NAT, Netfilter can run and other event message can be verified without declining efficiency. The correct operation of AODV routing protocol has been verified in both the Ad-hoc network test bed in which the embedded system was used, and Ad-hoc networks linked with Ethernet backbone network.

• Journal of Korea Water Resources Association
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• v.54 no.8
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• pp.629-641
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• 2021

In this study, a two-dimensional numerical model (Nays2DH) was applied to analyze the process of morphological changes in the river channel bed depending on the changes in the amount of flooding after fully opening the Sejong weir, which was constructed upstream of the Geum River. For this, numerical simulations were performed by assuming the flow conditions, such as a non-uniform flow (NF), unsteady flows (single flood event, SF), and a continuous flood event (CF). Here, in the cases of the SF and CF, the normalized hydrograph was calculated from real flood events, and then the hydrograph was reconfigured by the peak flow discharge according to the scenario, and then it was employed as the flow discharge at the upstream boundary condition. In this study, to quantitatively evaluate the morphological changes, we analyzed the time changes in the bed deformation the bed relief index (BRI), and we compared the aerial photographs of the study area and the numerical simulation results. As simulation results of the NF, when the steady flow discharge increases, the ratio of lower width to depth decreases and the speed of bar migration increases. The BRI initially increases, but the amount of change decreased with time. In addition, when the steady flow discharge increases, the BRI increased. In the case of SF, the speed of bar migration decreased with the change of the flow discharge. In terms of the morphological response to the peak flood discharge, the time lag also indicated. In other words, in the SF, the change of channel bed indicates a phase lag with respect to the hydraulic condition. In the result of numerical simulation of CF, the speed of bar migration depending on the peak flood discharges decreased exponentially despite the repeated flood occurrences. In addition, as in the result of SF, the phase lag indicated, and the speed of bar migration decreased exponentially. The BRI increased with time changes, but the rate of increase in the BRI was modest despite the continuous peak flooding. Through this study, the morphological changes based on the hydrological characteristics of the river were analyzed numerically, and the methodology suggested that a quantitative prediction for the river bed change according to the flow characteristic can be applied to the field.

• Proceedings of the IEEK Conference
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• 2004.08c
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• pp.576-580
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• 2004

In this paper, we present a design and implementation of a TV-Anytime compliant STB to provide personalized content consumption according to user preferences and various terminal/network conditions. This paper mainly details with a metadata engine which consists of meta data de-multiplexing, metadata decoding, and metadata-based content browsing. For personalized content consumption, the proposed metadata engine provides the following key functionalities: advanced EPG, non-linear segment navigation wirh Tables-of-Content and/or event-based summary, automatic recommendation of user-preferred programs, and etc. The implemented STB employing the metadata engine is successfully tested with a set of service scenarios in an end-to-end broadcasting test-bed.

• Journal of Information Processing Systems
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• v.10 no.3
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• pp.412-428
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• 2014

Request oriented sensor networks have stricter requirements than conventional event-driven or periodic report models. Therefore, in this paper we propose a minimum energy data aggregation (MEDA), which meets the requirements for request oriented sensor networks by exploiting a low power real-time scheduler, on-demand time synchronization, variable response frame structure, and adaptive retransmission. In addition we introduce a test bed consisting of a number of MEDA prototypes, which support near real-time bidirectional sensor networks. The experimental results also demonstrate that the MEDA guarantees deterministic aggregation time, enables minimum energy operation, and provides a reliable data aggregation service.

• The Korean Journal of Petroleum Geology
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• v.12 no.1
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• pp.34-42
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• 2006

Ichnology is the study of traces made by various organisms, which includes classification and description of traces, and interpretation of sedimentary process, behavior of organism and depositional environment based on traces and organism behavior. Ichnofacies, which is defined as the association of several traces related together with substrate characteristics and sedimentary processes, is closely related to depositional environment. Ichnology has been applied to sedimentology (to understand physical characteristics of depositional environment, sedimentation pattern and event bed), sequence stratigraphy (to recognize sequence boundaries and biostratigraphic discontinuities such as MFS, TSE and RSE), oil exploration (providing of many information without big cost) and palaeocology. Preliminary ichnological study on the Ganghwa intertidal flat shows that dominant ichofacies are changing with season and location, suggesting that their seasonal variation would be a good indicator to understand the seasonal change of sedimentary processes, the small- scale change of sedimentary environment and the preservation potential of such units. Ichnology on intertidal flat in western coast of Korea has a great potential to apply its results to petroleum geology as well as sedimentology.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.5
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• pp.1435-1442
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• 2014

This study presented numerical simulations of smooth-bed flows in the rectangular open-channel using the source code by OpenFOAM. For the analysis of the turbulent flow, Large Eddy Simulations were carried out and the dynamic sub-grid scale model proposed by Germano et al. (1991) is used to model the residual stress term. In order to analyze the coherent structure, the uw quadrant method proposed by Lu and Willmarth (1973) is used and the contribution rate and the fraction time of the instantaneous Reynolds stress are obtained in the Reynolds stress. The results by the present study are analyzed and compared with data from previous laboratory studies and direct numerical simulations. It is found that the contribution rate of the ejection events is larger than that of sweep events over the buffer layer in the open-channel flow over the smooth bed, however, the frequency of the sweep event is higher than that of the ejection events.

• Journal of Korea Water Resources Association
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• v.37 no.12
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• pp.1033-1041
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• 2004

A 2-dimensional numerical sediment transport model using erosion rates in undisturbed conditions has been developed and applied to calculating the suspended sediment concentrations and bed level changes in the Lower Fox River The model reduces inaccuracy of sediment model by using the accurate erosion rates obtained in a flume (called Sedflume). The flume has been developed to measure erosion rates as a function of sediment depth and at the situation of high shear stresses such as flood event. Both mechanisms of suspended load and bedload transport are included in the model. The model results were verified for the description of sediment transport in a straight channel and the sediment transport during flood event in the Lower Fox River The results of Lower Fox River simulation showed good agreements with the observed SS concentrations. This model can be used to simulate sediment transport under the high shear conditions such as flood.

• 한국지구물리탐사학회:학술대회논문집
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• 2006.06a
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• pp.187-192
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• 2006

The Korean peninsula has been considered as seismically intermediate region, since seismic activities have not been severe for long time and the active tectonic boundary is also located far away. However, the activities of earthquakes have been increased significantly for last decade. Since currently important structures and facilities are increasing rapidly in the Korean Peninsula, the importance of seismic design are increasing exponentially too. This study used observed ground motion of Fukuoka event including 11 afterschocks and then estimated seismic parameters representing seismic source, propagation effect, considering site amplification. The results were comparable to those of other studies in the same region. The results could be used as basic important parameters for seismic design of the important structures and facilities in Korean peninsula.