• Proceedings of the Korean Nuclear Society Conference
• /
• 1996.11a
• /
• pp.283-288
• /
• 1996

Direct safety injection into the reactor vessel downcomer annulus(DVI) is a fundamental feature of the KNGR(Korean Next Generation Reactor) four-train safety injection system. The numerical analysis of thermal mixing of ECC(Emergency Core Cooling) water through DVI with the water in the RVDC(Reactor Vessel Downcomer) annulus has been performed, in order to study the impact of nozzle location on the pressurized thermal shock and safety analysis. The results of this study show that the thermal mixing due to the natural circulation induced by the limiting accident conditions is sufficient to prevent temperature in the RVDC from dropping to the level of concern for PTS. When the DVI nozzle is located right above the cold leg, the temperature distribution at the outlet of flow field is most uniform. The tool used for numerical analysis is CFDS-FLOW3D.

• Progress in Superconductivity and Cryogenics
• /
• v.15 no.4
• /
• pp.21-25
• /
• 2013

In power grid, in order to level out the generation with demand, up-gradation of the system is occasionally required. This will lead to more fault current levels. However, upgrading all the protection instruments of the system is both costly and extravagant. This issue could be dominated by using Smart Fault Current Controller (SFCC). While the impact of Fault current Limiters (FCL) in various locations has been studied in different situations for years, the performance of SFCC has not been investigated extensively. In this research, SFCC which has adopted the characteristics of a full bridge thyristor rectifier with a superconducting coil is applied to three main locations such as load feeder, Bus-tie position and main feeder location and its behavior is investigated through simulation in presence and absence of small Distributed Generation unit (DG). The results show a huge difference in limiting the fault current when using SFCC.

• The Journal of Korean Medicine
• /
• v.18 no.2
• /
• pp.316-325
• /
• 1997

In a 36-month period, 23 selected Patients with Acute Cerebral Infarction were studied utilizing Computerized Tomography, Barthel Index in an attempt to correlate Brain Computerized Tomography findings with 1week, 4weeks rehabilitation and evaluate the influences of the size and location of the lesion. The study suggested that the size of the lesion had impact on 4 weeks rehabilitation. There was significant different between the patients with Middle Cerebral Artery Pial Territory Infarction(I.P.B.M.C.A.) lesion and the patients with Lacunar Infarction(L.I.), Striatocapsular Infarction(S.C.I.), Internal Watershed Infarction(I.W.I.) lesion, but there was no significant difference between the patients with L.I. lesion and the patients with S.C.I. lesion and the patients with I.W.I. lesion. The size and location of the lesion should be considered together in predicting the functional outcomes of Acute Cerebral Infarction.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.23 no.8
• /
• pp.752-758
• /
• 2013

The effect of external leakage on the acoustic performance of Helmholtz resonators is experimentally and numerically investigated. The transmission loss of the Helmholtz resonator with a circular perforated hole is measured by using an impedance tube setup. The experimental results are then compared with one-dimensional analytical and three-dimensional numerical results. As the size of the hole increases, the peak of the transmission loss shifts to higher frequency, especially for the holes on the cavity. While the transmission loss is almost independent of the location of the hole on the cavity, the impact of the hole location on the neck on the transmission loss is not negligible. The results show that one-dimensional analytical method can predict the overall trends, whereas three-dimensional numerical method is necessary for more accurate predictions.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.43 no.3
• /
• pp.46-55
• /
• 2001

Following the previous paper on development of the spatial location-allocation model of center villages (SLAMCV), this paper, the 2nd stage of the this study, aims to check up its applicability for several planning scenarios by the case study. Among 72 natural villages of Ucheon-myeon, Gangwon-do, Korea the highest single center was simulated as Uhang village and the higher double centers as Uhang and Jeonggeum villages, which coincided exactly with the existing centers. The SLAMCV was well operated for three planning scenarios such as selection of the 3rd center village and its hinter villages for Ucheon-myeon, Gargwon-do, Korea by dividing three living spheres, impact assessment evaluation of road improvement projects on the spatial accessibility, and analysis of centerality changes of settlement units by new road construction.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.15 no.9 s.102
• /
• pp.1108-1117
• /
• 2005

A robust damage detection method using short-time Fourier transform and beating phenomena is presented as an estimating tool of the healthiness of large structures. The present technique makes use of beating phenomena that manifest themselves when two signals of similar frequencies are added or subtracted. Unlike most existing methods based on vibration signals, the present approach does not require an analytic model for target structures. Furthermore, the main advantage of the proposed method compared to the competing diagnostic method using vibration data is its robustness. The proposed method is not affected by the amplitude of exciting signals and the location of exciting points. From a measuring view point. the location of sensing point have no influence on the performance of the present method. With a view to verifying the effectiveness of this method. a series of experiments are made and the results show its possibility as a robust damage diagnostic method.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
• /
• v.18 no.3
• /
• pp.347-354
• /
• 2020

Site characterization for decommissioning Kori Unit 1 is ongoing in South Korea after 40 years of successful operation. Kori Unit 1's containment building is assumed to be mostly radioactively contaminated, and therefore radiation exposure management and detailed contamination investigation are required for decommissioning and dismantling it safely. In this study, site-specific Derived Concentration Guideline Levels (DCGLs) were derived using the residual radioactivity risk evaluation tool, RESRAD-BUILD code. A conceptual model of containment building for Kori Unit 1 was set up and limited occupational worker building inspection scenario was applied. Depending on the source location, the maximum contribution source and exposure pathway of each radionuclide were analyzed. The contribution of radionuclides to dose and exposure pathways, by source location, is expected to serve as basic data in the assessment criteria of survey areas and classification of impact areas during further decommissioning and decontamination of sites.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.4 no.1
• /
• pp.55-62
• /
• 1996

The dynamic photoelastic technique has been utilized to investigate the possibility of relieving the large local singular stresses which are induce in the corner of a right angled indenter. The indenter compresses a semi-infinite body dynamically with an impact load applied on the top of the indenter. The effect of geometric changes to the indenter in terms of the diameter (d) and the location (ℓ) of the notch on the relieving of the dynamic contact stresses are investigated. A multi-spark-high speed camera with twelve sparks was used to take dynamic photographs. The contact singular stresses were found to be released by introducing the relief notch along the indenter. The optimal location and geometry of the relief notch need further experimental investigation.

• Journal of the Semiconductor & Display Technology
• /
• v.15 no.4
• /
• pp.92-96
• /
• 2016

Although deregistration attack is caused by simple spoofing the REGISTER message of a legitimate SIP UA, its impact is serious. The root cause of this attack is based on the fact that RFC 3261 allows the UA to remove the binding from the Location Server. In this paper, we propose a simple protection method to allow Registrar or Location Server just to ignore deregistration messages. We also show that this method works well by analyzing the process of registration and deregistration. Without any additional overhead such as an encryption or authentication, this method is able to establish a secure SIP environment efficiently protecting against the deregistration attack.

• Journal of Environmental Impact Assessment
• /
• v.31 no.1
• /
• pp.47-62
• /
• 2022

Wind power has been rapidly growing over last decade in the world as well as in South Korea as a feasible renewable energy source. Providing sustainable energy to all while securing environmental sustainability requires evidence based policy making and innovative solutions. Through analysis of 58 cases of South Korean Environmental Impact Assessment (EIA) Report, this paper seeks to identify answers to the following two questions. What are the key characteristics for inland windfarm? Is there a way of measuring environmental sustainability to compare each location to reduce negative environmental impact? Variables related to environmental sustainability of each windfarm case were collected from EIA report and the factor analysis of environmental variables was conducted to calculate the weight for each variable to build environmental sustainability index (ESI) to provide as evidence-based tools for decision making on the location of inland windfarm. 58 cases were categorized as three types 1) Mountain type 2) Ranch Type and 3) Coastal Type depending on their height and degree of naturalness. For analytical research, first, it was successfully calculated environmental sustainability of each windfarm case ranging from 1.04 (#33, Ranch type) to -1.44 (#55, Mountain type). Second, the analysis results showed that ranch type is most environmentally sustainable (Average ESI = 0.4551), followed by coastal type (Ave ESI = 0.3712) and lastly mountain type (Average ESI = -0.3457). These findings are consistent with the previous researches on inland windfarms and provides substantive policy implication on the renewable energy policies.