• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.6
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• pp.106-113
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• 2017

In this paper, we propose a suitable network topology for the Ethernet based Train Communication Network (TCN) for control system in a autonomous multi-articulated vehicle. We propose a network topology considering the structural constraints such as the number of cables and ports, and the performance constraints such as network response time and maximum throughput. We compare the network performances of star topology and daisy chain topology as well as hybrid topology, which is proposed in previous studies and a compromise between daisy chain and star topology. Here, the appropriate number of nodes in a group is obtained for the configuration of the hybrid topology. We first derive estimates of the network performance through simulation with different topologies, and then, implement the network by connecting the actual devices with each network topology. The performance of each topology is measured using various network performance measurement programs and the superiority of the proposed topology is described through comparison.

• Journal of Digital Contents Society
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• v.16 no.5
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• pp.775-781
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• 2015

EBS started 2HD MMS experimental broadcasting for the first time in Korea on Feb. 11, 2015. It uses the picture compression technique based on MPEG-2 CODEC, and applies the result of the experiment about variable bit rates and changes according to the scanning types, 1080i and 720p. But when changing channels, the delay in displaying picture occurs because of the operation of the variable GOP on MMS broadcasting, which optimizes image quality by application variable bit rates. In this study, verified the relationship between the decoding time of I frames and the GOP set in the encoding step by experimenting and analyzing ON-AIR TS. By using the verification data and adjusts the Encoder GOP parameters, improved the different video display time delays according to the scanning mode 1080i and 720p.

• Bulletin of the Korean Chemical Society
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• v.28 no.6
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• pp.947-952
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• 2007

Mycobacterium tuberculosis is a pathogen responsible for 2-3 million deaths every year worldwide. The emergence of drug-resistant and multidrug-resistant tuberculosis has increased the need to identify new antituberculosis targets. Acetohydroxy acid synthase, (AHAS, EC 2.2.1.6), an enzyme involved in branched-chain amino acid synthesis, has recently been identified as a potential anti-tuberculosis target. To assist in the search for new inhibitors and “receptor-based” design of effective inhibitors of tubercular AHAS (TbAHAS), we constructed four different structural models of TbAHAS and used one of the models as a target for virtual screening of potential inhibitors. The quality of each model was assessed stereochemically by PROCHECK and found to be reliable. Up to 89% of the amino acid residues in the structural models were located in the most favored regions of the Ramachandran plot, which indicates that the conformation of each residue in the models is good. In the models, residues at the herbicide-binding site were highly conserved across 39 AHAS sequences. The binding mode of TbAHAS with a sulfonylurea herbicide was characterized by 32 hydrophobic interactions, the majority of which were contributed by residue Trp516. The model based on the highest resolution X-ray structure of yeast AHAS was used as the target for virtual screening of a chemical database containing 8300 molecules with a heterocyclic ring. We developed a short list of molecules that were predicted to bind with high scores to TbAHAS in a conformation similar to that of sulfonylurea derivatives. Five sulfonylurea herbicides that were calculated to efficiently bind TbAHAS were experimentally verified and found to inhibit enzyme activity at micromolar concentrations. The data suggest that this time-saving and costeffective computational approach can be used to discover new TbAHAS inhibitors. The list of chemicals studied in this work is supplied to facilitate independent experimental verification of the computational approach.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.27 no.4
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• pp.265-271
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• 2014

304L stainless steel sheets are used as a primary barrier for the insulation of membrane-type liquefied natural gas(LNG) carrier cargo containment system. 304L stainless steel is a transformation-induced-plasticity(TRIP) steel that exhibits complex material behavior, because it undergoes phase transformation during plastic deformation. Since the TRIP behavior is very important mechanical characteristics in a low-temperature environment, significant amounts of data are available in the literature. In the present study, a uniaxial tensile test for 304L stainless steel was performed to investigate nonlinear mechanical characteristics. In addition, a viscoplastic model and damage model is proposed to predict material fractures under arbitrary loads. The verification was conducted not only by a material-based comparative study involving experimental investigations, but also by a structural application to the LNG membrane of a Mark-III-type cargo containment system.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.209.2-209.2
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• 2012

UFFO Burst Alert & Trigger telescope (UBAT) is one of major instruments of UFFO-Pathfinder. The UBAT aims at 10 arcmin resolution localization of Gamma Ray Bursts with X-ray coded mask technique. It has $400mm{\times}400mm$ coded mask aperture, hopper, shielding and detector module with effective area of $191cm^2$. The detector module consists of an assembly of 36 64-ch MAPMTs and $25mm{\times}25mm$ pixellated YSO crystal array, and associated analog and digital electronics of about 2500 channels. We performed a vibration test using a dummy MAPMT with the detector module structure to measure the indused stress applied onto the MAPMT. We designed a sub-structure on the detector module to avoid the resonance that would otherwise deforms the detector module structure. A finite element analysis confirms the reduction of the load acceleration down to 12g. The experimental results are to be reported. Consequently, it proves that the MAPMT arrays of the flight UBAT detector module structure would survive in the space launch environment.

• Structural Engineering and Mechanics
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• v.36 no.6
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• pp.759-783
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• 2010

In this paper, compressive strength of carbon fiber reinforced polymer (CFRP) confined concrete cylinders is formulated using a hybrid method coupling genetic programming (GP) and simulated annealing (SA), called GP/SA, and a robust variant of GP, namely multi expression programming (MEP). Straightforward GP/SA and MEP-based prediction equations are derived for the compressive strength of CFRP-wrapped concrete cylinders. The models are constructed using two sets of predictor variables. The first set comprises diameter of concrete cylinder, unconfined concrete strength, tensile strength of CFRP laminate, and total thickness of CFRP layer. The most widely used parameters of unconfined concrete strength and ultimate confinement pressure are included in the second set. The models are developed based on the experimental results obtained from the literature. To verify the applicability of the proposed models, they are employed to estimate the compressive strength of parts of test results that were not included in the modeling process. A sensitivity analysis is carried out to determine the contributions of the parameters affecting the compressive strength. For more verification, a parametric study is carried out and the trends of the results are confirmed via some previous studies. The GP/SA and MEP models are able to predict the ultimate compressive strength with an acceptable level of accuracy. The proposed models perform superior than several CFRP confinement models found in the literature. The derived models are particularly valuable for pre-design purposes.

• Journal of the Society of Naval Architects of Korea
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• v.55 no.3
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• pp.215-221
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• 2018

The structural design of offshore installations against explosions has been required to protect vital areas (e.g. control room, worker's area etc.) and minimize the damage from explosion accidents. Because the explosion accident will not only result in significant casualties and economic losses, but also cause serious pollution and damage to surrounding environment and coastal marine ecosystems. Over the past two decades, an incredible efforts was made to develop reliable methods to reduce and manage the explosion risk. Among the methods Quantitative Risk Assessment and Management (QRA&M) is the one of cutting-edge technologies. The explosion risk can be quantitatively assessed by the product of explosion frequency based on probability calculation and consequence analyzed using computer simulations, namely Computational Fluid Dynamics (CFD) and Finite Element Analysis (FEA). However to obtain reliable consequence analysis results by CFD and FEA, uncertainties associate with modeling and simulation are needed to be identified and validated by comparison with experimental data. Therefore, large-scaled explosion test procedure is developed in this study. And developed test procedure can be helpful to obtain precious test data for the validation of consequence analysis using computer simulations, and subsequently allow better assessment and management of explosion risks.

• Journal of Fashion Business
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• v.24 no.3
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• pp.30-39
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• 2020

This study was conducted to identify problems in domestic flame-retardant performance specifications. Currently, the domestic wallcovering anti-inflammatory regulations are not prepared for damage caused by smoke, with the carbonized area as the main function. In particular, given that smoke is the main cause of human casualties and injuries in a fire, it is reasonable that the flame density and toxicity of the wallcovering should also be the main performance indicators. The scope and method of research in this study were as follows. First, a prior study related to fire on various wallcoverings was considered. Second, it raised questions about the effects of smoke in the event of a fire and domestic anti-inflammatory performance tests. Third, textile wallcovering samples were manufactured with viscose rayon for experimental verification of the problems and tested by Korean and EU standards without flame retardant processing to analyze the differences between each regulation. Fourth, the performance of flame retardant wallcovering according to Korean standards was evaluated using smoke density and harmful gas testing methods. The results of each test were as follows. Non-fire retardant wallcovering was rejected by Korea standards. However, B-s1.d0 in Europe. Smoke density testing and harmful gas by domestic combustion processing on the same sample showed that the smoke density increased about 4.3 times more than before, and the harmful gas test showed that the suspension of the post-processing sample slowed earlier than the non-processed sample.

• Journal of Hydrogen and New Energy
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• v.21 no.5
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• pp.425-434
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• 2010

Integrated gasification combined cycle (IGCC) is an efficient and environment-friendly power generation system which is capable of burning low-ranked coals and other renewable resources such as biofuels, petcokes and residues. In this study some process modeling on a conceptual entrained flow gasifier was conducted using the ASPEN Plus process simulator. This model is composed of three major steps; initial coal pyrolysis, combustion of volatile components, and gasification of char particles. One of the purposes of this study is to develop an effective and versatile simulation model applicable to numerous configurations of coal gasification systems. Our model does not depend on the hypothesis of chemical equilibrium as it can trace the exact reaction kinetics and incorporate the residence time calculation of solid particles in the reactors. Comparisons with previously reported models and experimental results also showed that the predictions by our model were pretty reasonable in estimating the products and the conditions of gasification processes. Verification of the accuracy of our model was mainly based upon how closely it predicts the syngas composition in the gasifier outlet. Lastly the effects of change oxygen are studied by sensitivity analysis using the developed model.

• Journal of the Korea Concrete Institute
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• v.13 no.2
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• pp.130-138
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• 2001

This paper presents on the shear behavior prediction of reinforced concrete beams using Transformation Angle Truss Model (TATM). The TATM can evaluate the stress-strain relationships for cracked concrete by transforming stresses and strains for principal plane into those over the crack surfaces. This proposed analytical method simplifies the Fixed Angle Softened Truss Model (FA-STM) and removes the limitation of applicability of the FA-STM. The shear.strength and strain of reinforced concrete beams are predicted by using the TATM. For the verification of proposed method, experimental results of reinforced concrete beams were compared with theoretical results by the TATM, FA-STM and Rotating Angle Softened Truss Model (RA-STM).