• Journal of the Korean Society for Heat Treatment
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• v.13 no.5
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• pp.309-317
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• 2000

Demand for new nondestructive evaluations is growing to detect tensile crack growth behavior to predict long term performance of materials and structure in aggressive environments, especially when they are in non-visible area. Acoustic emission technique is well suited to these problems and has drawn a keen interests because of its dynamic detection ability, extreme sensitivity and location of growing defects. In this study, we investigated the strength of fire resistance steel for frame structure by tensile test after degradation treatment and analysed acoustic emission signals obtained from tensile test with time frequency analysis methods. In the T and TN specimens(under $600^{\circ}C$-10min ) consisting of ferrite and pearlite structure, most of acoustic emission events were produced near yield point, mainly due to the dislocation activities during the deformation. However, B specimen under $600^{\circ}C$-10min had a two peak which was attribute to the presence of martensite phase. The first peak is before yield point and the second after yield point. The sources of second acoustic emission peak were the debonding of martensite-martensite interface and the micro-cracking of brittle martensite phase. In $600^{\circ}C$-30min to $700^{\circ}C$-60min, many signals were observed before yield point and were decreased after yield point.

• Journal of the Korean Ceramic Society
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• v.42 no.2 s.273
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• pp.94-98
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• 2005

$RuO_2$ is widely studied as a lower electrode material for high dielectric capacitors in DRAM (Dynamic Random Access Memories) and FRAM (Ferroelectric Random Access Memories). In this study, the effects of hydrogen, oxygen, and argon Electron Cyclotron Resonance (ECR) plasma pretreatments on deposited by Metal Organic Chemical Vapor Deposition (MOCVD) $RuO_2$ nucleation was investigated using X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Atomic Force Microscopy (AFM) analyses. Argon ECR plasma pretreatment was found to offer the highest $RuO_2$ nucleation density among these three pretreatments. The mechanism through which $RuO_2$ nucleation is enhanced by ECR plasma pretreatment may be that the argon or the hydrogen ECR plasma removes nitrogen and oxygen atoms at the TiN film surface so that the underlying TiN film surface is changed to Ti-rich TiN.

• Smart Structures and Systems
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• v.21 no.5
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• pp.705-713
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• 2018

High-speed rail (HSR) has been in operation and development in many countries worldwide. The explosive growth of HSR has posed great challenges for operation safety and ride comfort. Among various technological demands on high-speed trains, vibration is an inevitable problem caused by rail/wheel imperfections, vehicle dynamics, and aerodynamic instability. Ride comfort is a key factor in evaluating the operational performance of high-speed trains. In this study, online monitoring data have been acquired from an in-service high-speed train for condition assessment. The measured dynamic response signals at the floor level of a train cabin are processed by the Sperling operator, in which the ride comfort index sequence is used to identify the train's operation condition. In addition, a novel technique that incorporates salient features of Bayesian inference and time series analysis is proposed for outlier detection and change detection. The Bayesian forecasting approach enables the prediction of conditional probabilities. By integrating the Bayesian forecasting approach with time series analysis, one-step forecasting probability density functions (PDFs) can be obtained before proceeding to the next observation. The change detection is conducted by comparing the current model and the alternative model (whose mean value is shifted by a prescribed offset) to determine which one can well fit the actual observation. When the comparison results indicate that the alternative model performs better, then a potential change is detected. If the current observation is a potential outlier or change, Bayes factor and cumulative Bayes factor are derived for further identification. A significant change, if identified, implies that there is a great alteration in the train operation performance due to defects. In this study, two illustrative cases are provided to demonstrate the performance of the proposed method for condition assessment of high-speed trains.

• Journal of Microbiology and Biotechnology
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• v.9 no.6
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• pp.804-810
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• 1999

There is a possibility that carvone, a monoterpene from spearmint (Mentha spicata), could induce the bph degradative pathway and genes in Alcaligenes eutrophus H850, which is a known Gram-negative PCB degrader with a broad substrate specificity that was thoroughly investigated with Arthrobacter sp. BIB, a Gram-positive PCB degrader. The strains BIB and H850 were unable to utilize and grow on the plant terpene [(R)-(-)-carvone] (50ppm) to be recognized as a sole carbon source. Nevertheless, the carvone did induce 2,3-dihydroxybiphenyl 1,2-dioxygenase (encoded by bphC) in the strain B lB, as observed by a resting cell assay that monitors accumulation of a yellow meta ring fission product from 4,4'-dichlorobiphenyl (DCBp). The monoterpene, however, did not appear to induce the meta cleavage pathway in the strain H850. Instead, an assumption was made that the strain might be using an alternative pathway, probably the ortho-cleavage pathway. A reverse transcription (RT)-PCR system, utilizing primers designed from a conserved region of the bphC gene of Arthrobacter sp. M5, was employed to verify the occurrence of the alternative pathway. A successful amplification (182bp) of mRNA transcribed from the N-terminal region of the bphC gene was accomplished in H850 cells induced by carvone (50ppm) as well as in biphenyl-growth cells. It is, therefore, likely that H850 possesses a specific PCB degradation pathway and hence a different substrate specificity compared with B1B. This study will contribute to an elucidation of the dynamic aspects of PCB bioremediation in terms of roles played by PCB degraders and plant terpenes as natural inducer substrates that are ubiquitous and environmentally compatible.

• Asian Journal of Atmospheric Environment
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• v.6 no.4
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• pp.304-313
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• 2012

In this study, the ${\AA}$ngstrom exponent for polydispersed aerosol during dynamic processes was investigated. Log-normal aerosol size distribution was assumed, and a sensitivity analysis of the ${\AA}$ngstrom exponent with regards the coagulation and condensation process was performed. The ${\AA}$ngstrom exponent is expected to decrease because of the particle growth due to coagulation and condensation. However, it is difficult to quantify the degree of change. In order to understand quantitatively the change in the ${\AA}$ngstrom exponent during coagulation and condensation, different real and imaginary parts of the refractive index were considered. The results show that the ${\AA}$ngstrom exponent is sensitive to changes in size distribution and refractive index. The total number concentration decreases and the geometric mean diameter of aerosols increase during coagulation. On the while, the geometric standard deviation approaches monodispersed size distribution during the condensation process, and this change in size distribution affects the ${\AA}$ngstrom exponent. The degree of change in the ${\AA}$ngstrom exponent depends on the refractive index and initial size distribution, and the size parameter changes with the ${\AA}$ngstrom exponent for a given refractive index or chemical composition; this indicates that the size distribution plays an important role in determining the ${\AA}$ngstrom exponent as well as the chemical composition. Subsequently, this study shows how the ${\AA}$ngstrom exponent changes quantitatively during the aerosol dynamics processes for a log-normal aerosol size distribution for different refractive indices; the results showed good agreement with the results for simple analytic size distribution solutions.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.6
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• pp.816-826
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• 2015

The present experiment evaluated the influence of moisture level and anaerobic fermentation on aerobic stability of total mixed ration (TMR). The dynamic changes in chemical composition and microbial population that occur after air exposure were examined, and the species of yeast associated with the deterioration process were also identified in both non-fermented and fermented TMR to deepen the understanding of aerobic deterioration. The moisture levels of TMR in this experiment were adjusted to 400 g/kg (low moisture level, LML), 450 g/kg (medium moisture level, MML), and 500 g/kg (high moisture level, HML), and both non-fermented and 56-d-fermented TMR were subjected to air exposure to determine aerobic stability. Aerobic deterioration resulted in high losses of nutritional components and largely reduced dry matter digestibility. Non-fermented TMR deteriorated during 48 h of air exposure and the HML treatment was more aerobically unstable. On dry matter (DM) basis, yeast populations significantly increased from $10^7$ to $10^{10}cfu/g$ during air exposure, and Candida ethanolica was the predominant species during deterioration in non-fermented TMR. Fermented TMR exhibited considerable resistance to aerobic deterioration. Spoilage was only observed in the HML treatment and its yeast population increased dramatically to $10^9cfu/g$ DM when air exposure progressed to 30 d. Zygosaccharomyces bailii was the sole yeast species isolated when spoilage occurred. These results confirmed that non-fermented and fermented TMR with a HML are more prone to spoilage, and fermented TMR has considerable resistance to aerobic deterioration. Yeasts can trigger aerobic deterioration in both non-fermented and fermented TMR. C. ethanolica may be involved in the spoilage of non-fermented TMR and the vigorous growth of Z. bailii can initiate aerobic deterioration in fermented TMR.

• Journal of KIISE:Information Networking
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• v.33 no.2
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• pp.113-130
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• 2006

Recently with the explosive growth of Internet applications, the attacks of hackers on network are increasing rapidly and becoming more seriously. Thus information security is emerging as a critical factor in designing a network system and much attention is paid to Network Intrusion Detection System (NIDS), which detects hackers' attacks on network and handles them properly However, the performance of current intrusion detection system cannot catch the increasing rate of the Internet speed because most of the NIDSs are implemented by software. In this paper, we propose a new high performance network intrusion using Network Processor. To achieve fast packet processing and dynamic adaptation of intrusion patterns that are continuously added, a new high performance network intrusion detection system using Intel's network processor, IXP1200, is proposed. Unlike traditional intrusion detection engines, which have been implemented by either software or hardware so far, we design an optimized architecture and algorithms, exploiting the features of network processor. In addition, for more efficient detection engine scheduling, we proposed task allocation methods on multi-processing processors. Through implementation and performance evaluation, we show the proprieties of the proposed approach.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.1
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• pp.383-391
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• 2010

The purpose of this study is to analyze influence of human resource efficiency of 32 university hospitals on revenue and expense. This study applies DEA(Data Envelopment Analysis) to evaluate human resource efficiency of the university hospitals. The results are as follows. First, university hospitals' average human resource efficiency are over 0.9 for the period 2005-2007. Second, in the relationship between revenue and efficiency, the revenue had any significant relation to human resource efficiency. Third, There is close correlation between revenue and human resource efficiency. The hospitals that are high on human resource efficiency were found to be high on revenue and expense. There is a dynamic relationship that connects revenue, expense and human resource efficiency. The higher the investment expense, the greater is the number of in-patients and out-patients which leads to higher growth and profits.

• Korean System Dynamics Review
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• v.2 no.2
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• pp.119-134
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• 2001

Since 1998, government-led Korean venture business boom now proceeds into the stage of market-oriented venture business growth. At such a moment, this research is to clarify the relations between the success factors of Korean venture businesses, based on domestic and foreign documentary surveys and inquiry surveys over domestic venture businesses. This research starts from the necessity to overcome the limits of the existing researches by uni-dimensional probing research into success factors of Korean venture businesses and to manifest the multi-dimensional relations between the success factors from the various viewpoints. And this research adopts System-Dynamics methodology to manifest and utilize relations among those factors, avoiding the existing metrical approaches. This research can be called a new approach to the current ecosystems of Korean venture in which whether venture businesses success in Korea is considered to depend on the list on the stock market. For this, this research implemented verification analysis through the simulations of each factor at various levels to build causality map which clarifies the causality of success factors of venture businesses through the System-Dynamics methodology and to utilize it as a way of supporting tool for decision-making of venture businesses. This research will be able to suggest the reactions depending on various internal and external situations. This research tried to manifest the causality map of each factor on the basis of inquiry surveys and documentary surveys to verify feedback among each factor by the SD methodology. This research will be a basis bolster up the still fragile substructure of venture businesses through an efficient analysis framework using the verification of SD methodology and resulting outcomes from this research.

• Journal of Oriental Neuropsychiatry
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• v.15 no.1
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• pp.9-25
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• 2004

Behavioral characteristics of Attention Deficit Hyperactivity Disorder(ADHD) is one of the most common mental disorders among children.child psyachiatry. Inattention, Hyperactivity that is done by hyperkinesis or minimal brain dysfunction is major sypmton in ADHD, But etiology and pathological facor of ADHD is very much or unkown.. We brought to about a Study on the Oriental - medical pathologic Understanding about Inattention, Hyperactivity symptom in ADHD within Don yui bo gam Book are as follows. 1. Oriental medical pathologic concepts about Inattention, Hyperactivity are continuous with process of Yang Qi(陽氣), an unbalance of qi(氣) and shen ming(神明), excess of seven emotions(七情), pathology of Huo(火). 2. Immanent factors in inattention, Hyperactivity are improper diet, overtiredness and seven emotions, are continuous with pathological process of the heart, liver, gall bladder, spleen, stomach, kidneys. 3. In oriental medicine, considered as a child's qi of shao yang, dynamic physiological feature, excess and want of yin and yang, organs and bowels, immanently imbalance in growth rather than a child's mental disorder 4. Inattention, looseness in ADHD-PI type are continuous with forgetfulness, improper overtiredness, shortage of qi, the interior heat syndrome due to yin deficiency within Don yui bo gam Book 5. Hyperactivity, impulsive actions in ADHD-C type are continuous with sudden palpitation, severe palpitation, delirium, fidgeting due to deficiency, fidgetiness, hyperactivity of huo due to yin deficiency, fever, febrile disease with accumulation of blood.