• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2010년 춘계학술대회논문집
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• pp.437-441
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• 2010

LES results of turbulent premixed combustion flows are introduced by using the dynamic sub-grid scale model based on G-equation describing the flame front propagation. The turbulent premixed combustion flows around bluff body and over backward facing step are analyzed to validate present formation. LES of swirling partially premixed combustion flame is also performed to conform the predictive capabilities of LES model and to prompt our understanding for the combustion flows over double cone swirl burner combustor by using CFD-ACE+ commercial code.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권1호
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• pp.50-67
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• 2015

The Cognitive Radio (CR) paradigm in tactical ad hoc networks is an important element of future military communications for network-centric warfare. This paper presents a novel Cognitive Link State Routing protocol for CR-based tactical ad hoc networks. The proposed scheme provides prompt and reliable routes for Primary User (PU) activity through procedures that incorporate two main functions: PU-aware power adaptation and channel switching. For the PU-aware power adaptation, closer multipoint relay nodes are selected to prevent network partition and ensure successful PU communication. The PU-aware channel switching is proactively conducted using control messages to switch to a new available channel based on a common channel list. Our simulation study based on the ns-3 simulator demonstrates that the proposed routing scheme delivers significantly improved performance in terms of average end-to-end delay, jitter, and packet delivery ratio.

• 한국안전학회지
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• 제28권4호
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• pp.81-90
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• 2013

To meet increased demand and lead to execution of successful overseas's plant construction, A prompt System is urgently needed to carries prevention and control of hazards associated with work related tasks and activities. This study is aimed to develop efficient and reliable safety management program to identify control measures for high risk activities by choosing and conducting proper risk assessment methodology that addresses Risk Priority Number(RPN) of adverse effects.

• Nuclear Engineering and Technology
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• 제52권11호
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• pp.2572-2580
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• 2020

Emerging gamma ray detection applications that utilize neutron-based interrogation result in the prompt emission of high-energy (>2 MeV) gamma-rays. Rapid imaging is enabled by scintillators that possess high density, high atomic number, and excellent energy resolution. In this paper, we evaluate the bright (50,000 photons/MeV) oxide scintillator, cerium-doped Gd₂Al₂Ga₃O₁₂ (GAGG(Ce)). A silicon photomultiplier (SiPM) array is coupled to a GAGG(Ce) scintillator array (12 × 12 pixels) and integrated into a coded-aperture based gamma-ray imaging system. A resistor-based symmetric charge division circuit was used reduce the multiplicity of the analog outputs from 144 to 4. The developed system exhibits 9.1%, 8.3%, and 8.0% FWHM energy resolutions at 511 keV, 662 keV, and 1173.2 keV, respectively. In addition, a pixel-identification resolution of 602 ㎛ FWHM was obtained from the GAGG(Ce) scintillator array.

• Bulletin of the Korean Chemical Society
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• 제35권4호
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• pp.1091-1097
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• 2014

Tageteserecta flower like zinc oxide nanostructures composed of hexagonal nanorods were synthesized via sonochemical method at room temperature. The synthesized nanomaterials exhibited wurtzite hexagonal phase structure with the single crystalline nature. The diameter of the individual nanorods that constitute the flower shaped zinc oxide structures is in the range of 120-160 nm. The sonication time effectively determined the morphological properties of the prepared materials. The catalytic activity of prepared zinc oxide nanostructures towards N-formylation reactions were evaluated without any surface modification and the nanostructures exhibited good reaction yield with the prompt recyclability behavior.

• 대한안전경영과학회지
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• 제13권1호
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• pp.115-119
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• 2011

To help the corporations ensure more efficient production management, the Enterprise Resource Planning (ERP) system has been introduced in operation, together with a variety of approaches to make improvements in terms of quality and productivity issues. Yet, with the different types of ERP systems in operation, many companies are going through many difficulties not only in having greatly reduced work efficiency but also in making prompt decisions from the entire group-based integrated information. In this study, the analysis was made on their own ERP systems and working processes operated by a company running the multiple number of productions from the domestic and the overseas suppliers, in order to support their interacted work flow regarding their products and help improve the work efficiency by establishing standardized ERP system. Through this, it is expected to ensure more competitive system in operation by securing the flexibility in the production as well as efficient resource distribution under the corporate context of cost reduction and quality improvement.

• Nuclear Engineering and Technology
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• 제34권2호
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• pp.117-131
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• 2002

Core disruptive accidents have been investigated at Korea Atomic Energy Research Institute(KAERI) as part of the work to demonstrate the inherent and ultimate safety of conceptual design of the Korea Advanced Liquid Metal Reactor(KALIMER), a 150 MWe pool- type sodium cooled prototype fast reactor that uses U-Pu-Zr metallic fuel. In this study, a simple method and associated computer program, SCHAMBETA, was developed using a modified Bethe-Tait method to simulate the kinetics and thermodynamic behavior of a homogeneous spherical core over the period of the super-prompt critical power excursion induced by the ramp reactivity insertion. Calculations of the energy release during excursions in the sodium-voided core of the KALIMER were subsequently performed using the SCHAMBETA code for various reactivity insertion rates up to 100 S/s, which has been widely considered to be the upper limit of ramp rates due to fuel compaction. Benchmark calculations were made to compare with the results of more detailed analysis for core meltdown energetics of the oxide fuelled fast reactor. A set of parametric studies were also performed to investigate the sensitivity of the results on the various thermodynamics and reactor parameters.

• Nuclear Engineering and Technology
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• 제49권5호
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• pp.920-927
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• 2017

With ever-advancing computer technology, the Monte Carlo (MC) neutron transport calculation is expanding its application area to nuclear reactor transient analysis. Dynamic MC (DMC) neutron tracking for transient analysis requires efficient algorithms for delayed neutron generation, neutron population control, and initial condition modeling. In this paper, a new MC steady-state simulation method based on time-dependent MC neutron tracking is proposed for steady-state initial condition modeling; during this process, prompt neutron sources and delayed neutron precursors for the DMC transient simulation can easily be sampled. The DMC method, including the proposed time-dependent DMC steady-state simulation method, has been implemented in McCARD and applied for two-dimensional core kinetics problems in the time-dependent neutron transport benchmark C5G7-TD. The McCARD DMC calculation results show good agreement with results of a deterministic transport analysis code, nTRACER.

• 한국컴퓨터정보학회논문지
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• 제24권2호
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• pp.49-56
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• 2019

In this paper, we propose an efficient congestion control scheme for interworking between 5GS(5G system) and LTE(Long-Term Evolution), called ECC(Efficient Congestion Control). The proposed congestion control scheme (ECC) is considered for coexistence of 5GS and legacy LTE systems and provides a prompt service connectivity based on overriding method while the backoff timer is running in the UE. Also, we briefly introduce Rel-15 5GS from a congestion control perspective and the proposed ECC and simulation results for the existing legacy congestion control mechanism and ECC in the 5GS-LTE coexisting environment are presented. Lastly, the improvement direction is considered in future 3GPP 5GS phase 2 standard in this paper.

• Nuclear Engineering and Technology
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• 제54권3호
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• pp.811-816
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• 2022

This work presents the methodology used to expand the capabilities of the Monte Carlo code OpenMC for the calculation of reactor kinetic parameters: effective delayed neutron fraction β_eff and neutron generation time L. The modified code, OpenMC(Time-Dependent) or OpenMC(TD), was then used to calculate the effective delayed neutron fraction by using the prompt method, while the neutron generation time was estimated using the pulsed method, fitting Λ to the decay of the neutron population. OpenMC(TD) is intended to serve as an alternative for the estimation of kinetic parameters when licensed codes are not available. The results obtained are compared to experimental data and MCNP calculated values for 18 benchmark configurations.