• Smart Structures and Systems
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• v.21 no.3
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• pp.305-320
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• 2018

The second half of the 20th century was marked with a significant raise in amount of railway bridges in Austria made of reinforced concrete. Today, many of these bridges are slowly approaching the end of their envisaged service life. Current methodology of assessment and evaluation of structural condition is based on visual inspections, which, due to its subjectivity, can lead to delayed interventions, irreparable damages and additional costs. Thus, to support engineers in the process of structural evaluation and prediction of the remaining service life, the Austrian Federal Railways (${\ddot{O}}$ BB) commissioned the formation of a concept for an anticipatory life cycle management of engineering structures. The part concerning concrete bridges consisted of forming a bridge management system (BMS) in a form of a web-based analysis tool, known as the LeCIE_tool. Contrary to most BMSs, where prediction of a condition is based on Markovian models, in the LeCIE_tool, the time-dependent deterioration mechanisms of chloride- and carbonation-induced corrosion are used as the most common deterioration processes in transportation infrastructure. Hence, the main aim of this article is to describe the background of the introduced tool, with a discussion on exposure classes and crucial parameters of chloride ingress and carbonation models. Moreover, the article presents a verification of the generated analysis tool through service life prediction on a dozen of bridges of the Austrian railway network, as well as a case study with a more detailed description and implementation of the concept applied.

• Journal of the Korean Society of Safety
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• v.18 no.4
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• pp.169-175
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• 2003

In this paper, and estimation method for estimating the states of underwater vehicle systems with external unknown disturbance is proposed. First, the dynamics of underwater vehicle are induced by Taylor series expansion in the vertical plane and horizontal plane, respectively. For constructing the system model, the external efforts, i.e., the sea surface disturbances, the current, wave and etc., are regarded as external unknown disturbances. Thus the disturbance is added as external input into state-space form of underwater vehicle system. To estimate the state of systems with unknown disturbance, a disturbance observer which does not effected the external unknown input is proposed, and the existence condition for the observer is given. Finally, the effectiveness of the proposed disturbance observer for robust control of underwater vehicle systems is verified by using numerical simulation.

• Electrical & Electronic Materials
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• v.9 no.1
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• pp.30-37
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• 1996

Previously, crystallization of a-Si:H films on glass substrates were limited to anneal temperature below 600.deg. C, over 10 hours to avoid glass shrinkage. Our study indicates that the crystallization is strongly influenced by anneal temperature and weakly affected by anneal duration time. Because of the high temperature process and nonconducting substrate requirements for poly-Si TFTs, the employed substrates were limited to quartz, sapphire, and oxidized Si wafer. We report on poly-Si TFT's using high temperature anneal on a Si:H/Mo structures. The metal Mo substrate was stable enough to allow 1000.deg. C anneal. A novel TFT fabrication was achieved by using part of the Mo substrate as drain and source ohmic contact electrode. The as-grown a-Si:H TFT was compared to anneal treated poly-Si TFT'S. Defect induced trap states of TFT's were examined using the thermally stimulated current (TSC) method. In some case, the poly-Si grain boundaries were passivated by hydrogen. A-SI:H and poly-Si TFT characteristics were investigated using an inverted staggered type TFT. The poly -Si films were achieved by various anneal techniques; isothermal, RTA, and excimer laser anneal. The TFT on as grown a-Si:H exhibited a low field effect mobility, transconductance, and high gate threshold voltage. Some films were annealed at temperatures from 200 to >$1000^{\circ}C$ The TFT on poly-Si showed an improved $I_on$$I_off$ ratio of $10_6$, reduced gate threshold voltage, and increased field effect mobility by three orders. Inverter operation was examined to verify logic circuit application using the poly Si TFTs.

• The Transactions of the Korean Institute of Power Electronics
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• v.13 no.4
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• pp.319-327
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• 2008

The demand of a three phase PWM inverter for the purpose of power control or grid-connecting is increasing. This inverter is connected to a grid through an L-filter or LCL-filter to reduce the harmonics caused by switching. An LCL-filter can reduce the harmonic of a low switching frequency and generate a satisfactory level of grid side current with a relatively low-inductance than an L-filter. But the additional poles caused by the LC part affects a stability problem due to induced resonance of the system. This paper presents a compensation method using a power theory to improve performance, the designed LCL-filter system and to reduce the stability problems caused by resonance. The effectiveness of the proposed algorithm is verified by simulations and experiments.

• Journal of Microbiology and Biotechnology
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• v.21 no.11
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• pp.1174-1178
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• 2011

Exopolysaccharides (EPSs) are microbial polysaccharides that are released outside of the bacterial cell wall. There have been few studies on EPS-producing lactic acid bacteria that can enhance macrophage activity and the underlying signaling mechanism for cytokine expression. In the current study, EPS-overproducing Lactobacillus (L.) paracasei KB28 was isolated from kimchi and cultivated in conditioned media containing glucose, sucrose, and lactose. The whole bacterial cells were obtained with their EPS being attached, and the cytokine-inducing activities of these cells were investigated. Gas chromatography analysis showed the presence of glucose, galactose, mannose, xylose, arabinose, and rhamnose in EPS composition. EPS-producing L. paracasei KB28 induced the expression of tumor necrosis factor (TNF)-${\alpha}$, interleukin (IL)-6, and IL-12 in mouse macrophages. This strain also caused the degradation of $I{\kappa}B{\alpha}$ and phosphorylation of the major MAPKs: Jun N-terminal kinase (JNK), p38, and extracellular signal-regulated kinase (ERK)1/2. The use of pharmacological inhibitors showed that different signaling pathways were involved in the induction of TNF-${\alpha}$, IL-6 and IL-12 by L. paracasei KB28. Our results provide information for a better understanding of the molecular mechanisms of the immunomodulatory effect of food-derived EPS-producing lactic acid bacteria.

• Journal of Microbiology and Biotechnology
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• v.30 no.9
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• pp.1395-1403
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• 2020

There is an increasing interest in using inactivated probiotics to modulate the host immune system and protect against pathogens. As the immunomodulatory function of heat-killed Lactobacillus brevis KCTC 12777BP (LBB) and its mechanism is unclear, we investigated the effect of LBB on immune response based on the hypothesis that LBB might exert stimulatory effects on immunity. In the current study, we demonstrate that administration of LBB can exert immune-stimulatory effects and promote clearance of foreign matters through enhancing phagocytosis. Treatment with LBB induced the production of TNF-α, IL-6, and nitric oxide in macrophages. Importantly, LBB directly increased the phagocytic activity of macrophages against bacterial particles. LBB was able to promote the production of TNF-α in bone marrow-derived macrophages and splenocytes and also increase the proliferation rate of splenocytes, suggesting that the immune-stimulating activity of LBB can be observed in primary immune cells. Investigation into the molecular mechanism responsible revealed that LBB upregulates TAK1 activity and its downstream ERK, p38, and JNK signaling pathways. To further confirm the immunomodulatory capability of LBB in vivo, we orally administered LBB to mice and assessed the effect on primary splenocytes. Splenocytes isolated from LBB-treated mice exhibited higher TNF-α expression and proliferative capacity. These results show that heat-killed L. brevis, a wildly consumed probiotic, may provide protection against pathogens through enhancing host immunity.

• Journal of the Korean institute of surface engineering
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• v.49 no.2
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• pp.152-158
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• 2016

We investigated the effect of capacitively coupled Ar plasma treatment on contact resistance ($R_c$) and channel sheet resistance ($R_{sh}$) of graphene field effect transistors (FETs), by varying their channel length in the wide range from 200 nm to $50{\mu}m$ which formed the transfer length method (TLM) patterns. When the Ar plasma treatment was performed on the long channel ($10{\sim}50{\mu}m$) graphene FETs for 20 s, $R_c$ decreased from 2.4 to $1.15k{\Omega}{\cdot}{\mu}m$. It is understood that this improvement in $R_c$ is attributed to the formation of $sp^3$ bonds and dangling bonds by the plasma. However, when the channel length of the FETs decreased down to 200 nm, the drain current ($I_d$) decreased upon the plasma treatment because of the significant increase of channel $R_{sh}$ which was attributed to the atomic structural disorder induced by the plasma across the transfer length at the edge of the channel region. This study suggests a practical guideline to reduce $R_c$ using various plasma treatments for the $R_c$ sensitive graphene and other 2D material devices, where $R_c$ is traded off with $R_{sh}$.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.6
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• pp.4158-4163
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• 2015

In this paper, the solutions of TE(transverse electric) scattering problems by a condutive strip grating over a dielectric layer are analyzed by using the FGMM(fourier galerkin moment method) and PMM(point matching method) known as a numerical method of electromagnetic fileld. The scattered electromagnetic fields are expanded in a series of floguet mode functions, the boundary conditions are applied to obtain the unknown field coefficients, and the conductive boundary condition is used for the relationship between the tangential electric field and the induced surface current density on the strip. The numerical results for the reflected and transmitted power of zeroth mode analyzed by according as the width and spacing of conductive strip, the relative permittivity and thickness of dielectric layer, and incident angles. Generally, according to the relative permittivity of dielectric layer increased, also the normalized reflected power of zeroth mode increased. To examine the accruacy of this paper, the numerical results of FGMM shown in good agreement compared to those of PMM.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.8
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• pp.1926-1938
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• 2009

In this study, detection system of the blood flow variation rate was implemented using the variation effect of bio electric impedance at time of the blood pressure measurement by means of impedance method. The blood pressure measurement was performed by the oscillometric method. The mean arterial pressure was calculated using maximum amplitude algorithm. The systolic and diastolic pressure were estimated by establishment of the various characteristic ratio according to mean arterial pressure range. Alternative static current source and lock_in amplifier were introduced to impedance measurement. The variation of blood volume was measured using variation bio impedance according to induced cuff pressure at measuring area.

• International Journal of Highway Engineering
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• v.11 no.1
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• pp.85-94
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• 2009

In cost estimation of construction, several methods including quantity-per-unit costing, job costing, unit cost estimation and lumpsum estimation are being utilized in Korea. Among them, a Quantity-per-unit Costing Method is used as a standard of cost estimation in public and private works. This paper presents the realistic job-costing method on all road construction tasks through statistical analyses with field survey data to solve the problems induced by the existing quantity-per-unit costing method. Furthermore, it was found that the newly developed job costing method is able to produce a simple costing procedure and a more actual construction cost estimation by a case study, which was performed to compare particular construction costs produced by two different methods, existing quantity-per-unit costing and newly developed job costing. These methods is compared by Case-study about sub-base. In the case of Job costing method, the estimate is shorter than the other case about 50% and can make up for the weak point about instrument in the current Standard of cost estimation. And it can be depict by Job Costing method about progress of work for using by a plan about construction management.