• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.24 no.5
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• pp.553-560
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• 2015

Fracture mechanics analysis for cracked pipes is essential for applying the leak-before-break (LBB) concept to nuclear piping design. For LBB assessment, crack instability and leak rate should be predicted accurately for through-wall cracked pipes. In a nuclear piping system, elbows are connected with straight pipes by circumferential welding; this weld region is often considered a critical location. Hence, accurate crack assessment is necessary for cracks in the interface between elbows and straight pipes. In this study, the stress intensity factor (SIF) and elastic crack opening displacement (COD) were estimated through detailed 3D elastic finite element (FE) analyses. Based on the results, closed-form solutions of shape factors for calculating the SIFs and elastic CODs were proposed for circumferential through-wall cracks in the abovementioned interfaces under internal pressure. In addition, the effect of the elbow on shape factors was investigated by comparing the results with the existing solutions for a straight pipe.

• Journal of IKEEE
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• v.14 no.1
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• pp.33-39
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• 2010

In this paper, a 5Gb/s receiver with an adaptive equalizer for serial link interfaces is proposed. For effective gain control, a least-mean-square (LMS) algorithm was implemented with two internal signals of slicers instead of output node of an equalizing filter. The scheme does not affect on a bandwidth of the equalizing filter. It also can be implemented without passive filter and it saves chip area and power consumption since two internal signals of slicers have a similar DC magnitude. The proposed adaptive equalizer can compensate up to 25dB and operate in various environments, which are 15m shield-twisted pair (STP) cable for DisplayPort and FR-4 traces for backplane. This work is implemented in $0.18-{\mu}m$ 1-poly 4-metal CMOS technology and occupies $200{\times}300{\mu}m^2$. Measurement results show only 6mW small power consumption and 2Gbps operating range with fabricated chip. The equalizer is expected to satisfy up to 5Gbps operating range if stable varactor(RF) is supported by foundry process.

• IE interfaces
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• v.21 no.4
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• pp.385-393
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• 2008

Corporate's survival or bankruptcy has been determined by interaction of macroeconomic environment, industrial dynamic environment and internal process of corporate. This study attempts to examine financial factors' differences that have influence on corporate's survival or bankruptcy before and after foreign exchange crisis in Korea. The first previous empirical study that researched the cause of corporate's survival or bankruptcy in the financial ratios was attempted by Altman in 1968. Recently various survival analysis models have been published. In this paper, Multiple Discriminant Analysis model is used. We divide analytical periods into before and after foreign exchange crisis and sample randomly survival or bankruptcy firms for each period. Independent variables are financial ratios which represent growth, profitability, activity, liquidity and productivity. In conclusion, this paper examines hypothesis as "There are differences of significant financial factors before and after foreign exchange crisis."

• Journal of the Korea Computer Industry Society
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• v.2 no.8
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• pp.1015-1024
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• 2001

As the internet environment has been rapidly changed, the scale of internet network that needs to be managed has been magnified. In this way, the recognition for the importance of security became extensive, and numerous security systems for the protection of internal information were introduced. But decentralized security systems because of there use of different user interfaces undergo difficulties in effective security management as well as prompt coping when an obstacle happens causing a corpulence of in the security management part. In this paper, I propose an integrated security management system which can grasp the situation of each system and manage every system in the center so that we can consistently and integrally manage every system. Integrated security management system with multi agents has the advantages of prompt coping with obstacles, and the minimization of weaknesses that different security solutions have, and of consistent control and management for decentralized security systems.

• IE interfaces
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• v.17 no.3
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• pp.349-358
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• 2004

The organizations that adopted ISO 9000:1994 have upgraded to ISO 9001:2000 family through transition period by December, 2003. This paper focuses on the implementation of ISO 9001:2000 QMS in Busan and Kyungnam provinces where most machinery and metal manufacturing companies are located. Based on the questionnaire survey, we calculate ordinal association measures of requirements questions, perform factor analysis, and test three hypotheses to ascertain if there is any difference in implementing ISO 9001:2000 QMS. Results show that a professional manager-CEO maintains QMS general requirements(4.1), work environment(6.4), measurement analysis and improvement general(8.1), and monitoring and measurement(8.2) better than an owner-CEO. In addition, it has been found that customer focus(5.2) and improvement(8.5) are well maintained in companies by internal developmental reasons, and infrastructure(6.3) and purchasing(7.4) are well maintained by companies with long term implementation.

• IE interfaces
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• v.17 no.spc
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• pp.11-19
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• 2004

The purpose of this study is to identify the determinants of new venture performance according to years of operation in the view of integrated research framework. We propose the integrated new ventures performance model which is composed of entrepreneur, organization/resources, industrial environment, strategy/foundation process and availability of supporting systems as corresponding variables to new ventures performance. The determinants of new venture performance according to years of operation are identified through the multi-variate statistical analysis such as moderating regression analysis with the data gathered from 110 executives of venture companies. For internal variables, entrepreneur's managerial ability and technical expertise and employee's ability affect venture's performance increasingly as years of operation increases but resource procurement ability affects decreasingly. Related to external variables, years of operation plays positive moderating role on market size growth and supporting system availability, but negative role on government venture policy for venture performances. Though this study has limitation of small sample, limited questionnaire and performance measure, it has managerial contribution of identifying determinants of new venture performance according to years of operation.

• IE interfaces
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• v.24 no.2
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• pp.128-138
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• 2011

This research proposes a resource allocation model of Data QC (Quality Control) activities using COQ (Cost of Quality). The model has been developed based on a series of research efforts such as COQ classifications, weight determination of Data QC activities, and an aggregation approach between COQ and Data QC activities. In the first stage of this research, COQ was divided into the four typical classifications (prevention costs, appraisal costs, internal failure costs and external failure costs) through the opinions from five professionals in Data QC. In the second stage, the weights of Data QC activities were elicited from the field professionals. An aggregation model between COQ and Data QC activities has been then proposed to help the practitioners make a resource allocation strategy. DEA (Data Envelopment Analysis) was utilized for locating efficient decision points. The proposed resource allocation model has been validated using the case of Korea national defense information system. This research is unique in that it applies the concept of COQ to the data management for the first time and that it demonstrates a possible contribution to a real world case for budget allocation of national defense information.

• Transactions on Electrical and Electronic Materials
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• v.6 no.4
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• pp.177-185
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• 2005

Fatigue characteristics of lead zirconate titanate (PZT) films deposited by electron cyclotron resonance plasma enhanced chemical vapor deposition (ECR-PECVD) were investigated. The fatigue characteristics were investigated with respect to PZT film thickness, domain structure, fatigue pulse height, temperature, electrode materials and electrode configurations. The used top and bottom electrode materials were Pt and $RuO_2$. In the fatigue characteristics with fatigue pulse height and PZT film thickness, the fatigue rates are independent of the applied fatigue pulse height at the electric field regions to saturate the P-E hysteresis and polarization $(P^*,\;P^A)$ characteristics. The unipolar and bipolar fatigue characteristics of PZT capacitors with four different electrode configurations $(Pt//Pt,\;Pt//RuO_2,\;RuO_2//Pt,\;and\;RuO_2//RuO_2)$ were also investigated. The polarization-shifts during the unipolar fatigue and the temperature dependence of fatigue rate suggest that the migration of charged defects should not be expected in our CVD-PZT films. It seems that the polarization degradations are attributed to the formation of charged defects only at the Pt/PZT interface during the domain switching. The charged defects pin the domain wall at the vicinity of Pt/PZT interface. When the top and bottom electrode configurations are of asymmetric $(Pt//RuO_2,\;RuO_2//Pt)$, the internal fields can be generated by the difference of charged defect densities between top and bottom interfaces.

• Journal of IKEEE
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• v.20 no.4
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• pp.424-427
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• 2016

A microwave NDI(Nondestructive Inspecting) method, based on SAR(Synthetic Aperture Radar) for inspecting such internal flaws or physical demage of FRP(Fiber Reinforced Polymer), is proposed in this paper. When a microwave is incident perpendicularly toward a multilayer dielectric FRP material, it gives a good response for the interfaces or transverse cracks. Interface depths or defect positions can be presented from the reflection waves, as using SAR imagery technique. As a result, it can be shown that such a SAR system can effectively inspect the type, size, or location of flaws within FRP composite material.

• Journal of the Korean Ceramic Society
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• v.42 no.7 s.278
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• pp.509-515
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• 2005

Interfacial reactions at LSGM electrolyte and NiO-GDC anode interfaces were thoroughly investigated with Environmental Scanning Electron Microscopy (ESEM-PHlLIPS XL-30) and Energy Dispersive X-ray (EDX-Link XL30). According to the analysis, serious reaction zone was observed at LSGM/NiO-GDC interface. It was found that the reaction layer was originated from the chemical reaction between NiO and LSGM. The reaction products were identified as La deficient form of LSGM based perovskite and Ni-La-O compounds such as LaSrGa$_{3}$O$_{7}$ and LaNiO$_{3}$ from the X-Ray Diffraction (XRD, Philips) analysis. According to the electrical characterization, interfacial layer was very electrically resistive which would be the cause of high internal resistance and low power generating characteristic of the unit cell.