• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.148-152
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• 2000

The experimental study was performed to investigate the effects of centrifugal condition on the segregated layers of materials and the compressive strength of concrete for pretensioned spun high strength concrete (PHC) pile. The considering factors in the test were the centrifugal time and the magnitude of centrifugal force. These factors have been found to have found to have the great influence on the segregation and the concrete strength. The moderate centrifugal condition has to be fitted for the quality assurance in the production of PHC pile, especially to provide the adequate concrete cover over the tendons.

• Journal of the Korean Society of Systems Engineering
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• v.4 no.1
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• pp.31-34
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• 2008

As a supply contract for 100 new high-speed rolling stocks(KTX-II) was made 8th June 2006, System Engineering process has been applied to introduce the high-speed rolling stocks successfully and to manage the total life cycle systematically from Pre-concept Phase, Contract Phase, Preliminary and Critical Design Review, Production, Test and Verification, Acceptance and Operation to assurance for a flaw.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.7
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• pp.4828-4834
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• 2015

From the moment that a firing pin triggers the detonator to the moment that a grenade leaves a barrel is called Action Time. Since a loading and percussion of 40mm grenade happens simultaneously, action time should be within a certain time in order to prevent a Jamming malfunction. Previously, unreliable action time device of 40mm grenade made it difficult to improve quality assurance of K4 Grenade Machine Gun. Here, various sensors were compared and a special device was designed to seek an accurate measurement on action time. In this device, the gap between a signal from an optical sensor in Firing Pin and that from Eddy current probe in the barrel was recorded and data were sent to a computer in real time. Confirming if action time is within the criteria, it is expected that action time plays an important role in quality assurance on 40mm grenade.

• Journal of the Korean Society of Radiology
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• v.16 no.3
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• pp.211-216
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• 2022

In radiation therapy, accurate Quality Assurance (QA) is required to irradiate tumor tissue while minimizing damage to normal tissue. Therefore, a dosimeter that can accurately measure radiation is needed. The purpose of this study is to develop a highly efficient radiation dosimeter with high sensitivity by applying a particle in binder method that can reduce manufacturing costs and simplify processes to perovskite materials that are cheaper and simpler to manufacture. By evaluating the response characteristics to high-energy photon, the applicability of QA dosimeter to radiation therapy was evaluated. As a result of reproducibility evaluation, RSD at 6 MV energy was presented as 1.178% and 15 MV energy was presented as 1.141%. As a result of linearity evaluation according to linear regression analysis, R² values of 0.9999 were presented under each condition of 6 MV and 15 MV energy. It was found that the CsPbBr₃ dosimeter manufactured based on the results of reproducibility and linearity evaluation is highly applicable as a QA dosimeter in the field of therapeutic radiation. The CsPbBr₃ dosimeter manufactured in this study presented more than the standard performance in the evaluation of reproducibility and linearity, and it can be used as a radiotherapy QA dosimeter through improvement.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.1
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• pp.185-194
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• 2012

Deepwater oil is becoming more attractive because most onshore and shallow water oil is developing or developed. With the on-going trend to deepwater oil developments, flow assurance problems which prevent oil flow from reservoir to processing facilities are becoming an issue because deposited material can be occurred in case oil is exposed to very different environment from reservoir. Wax deposition which is one of flow assurance problems can be a major technical and economic issue because it is very sensitive to temperature. In order to predict and mitigate wax problems, the precise measurement of wax appearance temperature (WAT) which is the starting temperature of wax precipitation is very important. Various methods have been suggested for WAT measurement of opaque oil because there is no standard method for opaque oil. In this study, the WAT of opaque oil samples was measured using viscosity measurement method, differential scanning calorimetry, filter plugging method, and pressurized filter plugging method. Wax deposition test and high temperature gas chromatography analysis were applied to verify measured WAT. As a result of study, the WAT of opaque oils was successfully measured and verified. If WAT measurement methods of opaque oil related to oil characteristics is systematized using the results of this study, it can be a valuable tool for WAT measurement of opaque oil and flow assurance related to wax deposition.

• Korean Journal of Comparative Education
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• v.18 no.4
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• pp.27-55
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• 2008

Since quality assurance and enhancement (QAE) raises the fundamental issue of the survival of higher education institutions and national competitiveness, guides on quality assurance (QA) are popular both domestically and worldwide. Despite the focus in many countries on trying to establish and implement QA systems, no clear investigation has been conducted on what actually happens in the institutions. Therefore, the present study examines the quality control system of the UK at an institutional level by focusing on the case of Scotland QAE. As Scottish QAE especially emphasizes student engagement and quality culture, this study investigates the present QAE situation in the institution and current ideas for better future practices by analyzing the perceptions of internal stakeholders' from the University of Edinburgh, School of Education, based on the stakeholder theory and implications for other contexts. The stakeholder analysis results demonstrate the successful application of QAE with a high level of understanding and stakeholder interest. However, the current strategy is missing certain opportunities for staff and students. Therefore, further information disclosure, formative evaluation, better communication and administrational supports are required for improved practice.

• Journal of the Korean Society of Radiology
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• v.13 no.3
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• pp.333-338
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• 2019

In the field of radiotherapy, the Quality Assurance(QA) procedure to verify the safety of treatment is considered to be very important. However, due to various problems of the conventional dosimeters used for the QA, researches on these dosimeters have been actively carried out to replace them. In this study, to maximize the sensitivity by visible light(VL) emitted from phosphors, blended hybrid sensors were fabricated by blending various weight percent(wt%) of $Gd_2O_2S:Tb$ which is a phosphor with excellent fluorescence efficiency into $PbI_2$. Then, the electrical properties to high energy radiation from the blended sensors and the pure $PbI_2$ sensor were compared and evaluated. As a result of the sensitivity evaluation, the sensor of 3wt% showed the highest value with more than 40% difference from the other sensors, and gradual decreasing in sensitivity was observed with increasing wt% except for the sensor of 3wt%. Also, in the reproducibility evaluation, the pure $PbI_2$ sensor exhibited a large variation in coefficient of variation(CV)>0.015, while all the blended sensors showed CV<0.015.

• Information Systems Review
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• v.17 no.2
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• pp.1-27
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• 2015

Internet shopping has continued to grow rapidly in the past decade. The main cause of this growth was the cheap price and convenience. However, internet shopping is uncertain compared to off-line shopping malls. Consumers don't have a chance to directly see and touch the products they will purchase. Many previous studies have suggested a trust to resolve this uncertainty. For purposes of the study, we examined how trust affects word-of-mouth effect and third-party assurance. Furthermore, using perceived risk and perceived price as moderating effects, we analyzed to see how each group-that is, those with high perceived risk and low perceived risk and those with high perceived price and low perceived price-shows differences in trust building. The results of empirical study found that both two variables of word-of-mouth effect and third-party assurance have significant impacts in trust building of internet shopping malls. It was proven that each group-those with high perceived risk and low perceived risk and those with high perceived price and low perceived price-showed differences in trust building. The results are expected to provide both the researchers of the trust study and hands-on worker with important implications.

• Progress in Medical Physics
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• v.30 no.4
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• pp.128-138
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• 2019

Purpose: Segmental analysis of volumetric modulated arc therapy (VMAT) is not clinically used for compositional error source evaluation. Instead, dose verification is routinely used for plan-specific quality assurance (QA). While this approach identifies the resultant error, it does not specify which machine parameter was responsible for the error. In this research study, we adopted an approach for the segmental analysis of VMAT as a part of machine QA of linear accelerator (LINAC). Methods: Two portal dose QA plans were generated for VMAT QA: a) for full arc and b) for the arc, which was segmented in 12 subsegments. We investigated the multileaf collimator (MLC) position and dosimetric accuracy in the full and segmented arc delivery schemes. A MATLAB program was used to calculate the MLC position error from the data in the dynalog file. The Gamma passing rate (GPR) and the measured to planned dose difference (DD) in each pixel of the electronic portal imaging device was the measurement for dosimetric accuracy. The eclipse treatment planning system and a MATLAB program were used to calculate the dosimetric accuracy. Results: The maximum root-mean-square error of the MLC positions were <1 mm. The GPR was within the range of 98%-99.7% and was similar in both types of VMAT delivery. In general, the DD was <5 calibration units in both full arcs. A similar DD distribution was found for continuous arc and segmented arcs sums. Exceedingly high DD were not observed in any of the arc segment delivery schemes. The LINAC performance was acceptable regarding the execution of the VMAT QA plan. Conclusions: The segmental analysis proposed in this study is expected to be useful for the prediction of the delivery of the VMAT in relation to the gantry angle. We thus recommend the use of segmental analysis of VMAT as part of the regular QA.

• Journal of Korea Society of Digital Industry and Information Management
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• v.5 no.4
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• pp.231-247
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• 2009

With the growth of e-commerce banks make the best use of internet banking which can provide all sorts of financial services in cyber space and satisfy customers beyond traditional banking services which are cash reserve and loan based on retail. For survival of internet banking high quality of service should be provided to customers. For this, the attributes of service quality in internet banking should be identified first. The studies on scale of service quality in internet banking have been divided into two ways. While traditional way has focused on SERVQUAL, several researchers have developed scale of e-service quality. However, the dimension of e-service quality is applied from the traditional dimension of service quality. In this paper five dimensions of tangibles, reliability, responsiveness, assurance, and empathy based on SERVQUAL are used as scale of service quality in internet banking through reviewing previous studies. In addition, because service value is correlated to service quality, the dimensions of service quality can affect e-service value. The positive relationship among e-service value, customer satisfaction, and customer loyalty in online or offline service has been identified by previous studies. The purpose of this study is to identify the relationship among service quality, e-service value, customer satisfaction, and customer loyalty in internet banking. SPSS 12.0 is used to test validity and reliability of questionnaire items and correlation of variables and AMOS 4.0 is used to test the hypotheses. The results of this study show that the responsiveness, assurance, and empathy factors of service quality have a positive effect on service value and that the tangible and assurance factors have a positive effect on customer satisfaction. It also shows that e-service value affects positively customer satisfaction and loyalty. Customer satisfaction affects positively customer loyalty. Therefore, to enhance customer satisfaction and loyalty, service quality and value of internet banking should be improved through reinforcing customers' trust in internet service quality.