• The Journal of Korean Association of Computer Education
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• v.23 no.1
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• pp.29-36
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• 2020

Various items were used as evaluation tools that identify the student's abilities accurately to confirm the completion of learning. Among them, the multiple choice item has the advantages of high objectivity and reliability in scoring, but it cannot remove the factor of guessing. In this paper, the multiple choice items are classified into two types according to the relationship between the questionnaire and the choices. One is the type used in the classical test theory with the probability of guessing 1/k for k choices and the other is the novel proposed type which introduces the concept of partial knowledge. In the proposed type, the probability of guessing when the number of knowledge i is (i+1)/k for k choices. Based on the assumptions of the previous theories about multiple choice items, we derive the guessing parameter about the proposed type. And we analyzed the effect of the guess on the correct answer in the existing type and the proposed type. This shows that the proposed type has more question guessing than the existing type.

• Journal of Digital Contents Society
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• v.10 no.2
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• pp.309-318
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• 2009

The youth of this research using the Internet, navigate to the factors and relationships with Internet addiction, and the sense of seeking and want to verify the effectiveness of the regulation of interpersonal relationships. Who was studied 347 high school students in the Gyeonggi Province. SPSS win 13.0 program to study the reliability coefficient was calculated and analysis of care. Regression analysis, control theory verification (MMR) was conducted. Factor analysis using the Internet when the Internet addiction affect, interpersonal relationships and the pursuit of a sense of interaction was confirmed by the positive control the effects. Verification results of this research using the Internet to the fact that Internet addiction Static (+) gave. Pursuit of interpersonal relationships and a sense of control and the interaction effects were different.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.30 no.4
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• pp.197-216
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• 2019

The study aimed to investigate the motivation and user satisfaction of medical school graduate students using specific academic information sites, and examines the effect of usage motivation factors on user satisfaction. This study was conducted from September 10, 2018 to September 21, 2018 by a large medical school graduate student in Seoul, and analyzed 135 valid responses. According to the analysis, the degree of reliability and interactivity of PubMed is higher than that of Google Scholar in medical school graduate students' use of academic information sites. It was found to have a significant effect on user satisfaction of academic information sites. In particular, convenience has the greatest influence on users' choice of academic information sites. The results of the study are of theoretical implications in that the discussion of academic information services through web sites is explained in terms of use and satisfaction in the context of medical information. On the other hand, specific research results provide practical implications for improving the services of medical-related academic search engines.

• Journal of the Korea Convergence Society
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• v.11 no.9
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• pp.163-168
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• 2020

The purpose of this study is to investigate the relationship between the selection factors of sports climbing center, customer satisfaction, and re-registration. Data collection for the purpose of this study was collected through S center, B center, V center located in Seoul and K center located in Gyeonggi-do. A total of 296 valid samples were used for the analysis. To make sure the theory, it was based on analysis of frequency, factor analysis, reliability analysis and multiple regression. First of all, it was found that the factors of selecting the sports climbing center partially affected the customer satisfaction level. Second, it was found that the factors of selecting the sports climbing center partially affected the decision to re-register.

• Journal of KIISE:Computer Systems and Theory
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• v.30 no.10
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• pp.533-543
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• 2003

With the increase of interests in cluster, there have been a number of research efforts to address the high availability issues on cluster. However, there are no kernel-level group communication systems to support the development of kernel-level application programs and it is not easy to use traditional user-level group communication systems for the kernel-level applications. This paper presents the design and implementation issues of KCGCS(Kernel-level Cluster Group Communication System), which is a kernel-level group communication module for linux cluster. Unlike traditional user-level group communication systems, the KCGCS uses light-weight heartbeat messages and a ring-based heartbeat mechanism, which allows users to implement scalable failure detection mechanisms. Moreover, the KCGCS improves the reliability by using distributed coordinators to maintain membership information.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.19 no.1
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• pp.38-44
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• 2007

Using the mathematical model suggested by Bennet et al.(1992), the reflection and transmission coefficients by a circular pile breakwater has been investigated in the framework of potential theory. Flow separation due to sudden contraction and expansion is generated and is the main cause of significant energy loss. Therefore, evaluation of exact energy loss coefficient is critical to enhance the reliability of mathematical model. To obtain the energy loss coefficient, 2-dimensional turbulent flow is analyzed using the FLUENT commercial code. The energy loss coefficient can be obtained from the pressure difference between upstream and downstream. Energy loss coefficient is the function of porosity and the relation equation between them is suggested throughout the curve fitting processing. To validated the suggested relation, comparison between the analytical results and the experimental results is made for four different porosities with good agreement.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2012.10a
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• pp.169-170
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• 2012

The efforts for improving 'Maritime Traffic Safety Assessment Scheme(MTSA scheme)' have continued to the present since May 27th, 2009. But recently, there's a controversy about whether it has been performed properly or the results is significant. These new discussions were arose from lack of validity and appropriateness we had yet to find. At this point, it needs to establish sound MTSA scheme through the comprehensive review. This research developed a suitable meta-evaluation model for MSTA with applying theory of the teta-evaluation, that is the evaluation of evaluations and verified by using meta-evaluation methods like as literature studies, expert reviews, surveys and etc. The results of this study can be used to evaluate MTSA activities and it will contribute to improving MTSA scheme.

• Journal of the Korean Institute of Gas
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• v.14 no.4
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• pp.31-36
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• 2010

An alternative method is presented for predicting failure probability of pipelines with corrosion defects in this paper. The failure of corroded pipeline occurs when the operating pressure is grater than the remaining strength of the pipeline, and a limit state function can be defined as the differences between the remaining strength and the operating pressure. Then, based on structural reliability theory, we can estimate the failure probability of corroded pipeline, which is dependent on elapsed time of the pipeline with active corrosion defects. In this study, a root finding (RF) method has been adopted to solve the limit state function instead of Monte-Carlo simulation (MCS) method which traditionally has been employed to solve those kinds of problems. The calculation results shows that there are only small differences between the RF and the MCS method but the RF has higher efficiency in calculation than the MCS.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.11
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• pp.4087-4094
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• 2010

The sensor data which is measured by Quadruped robot is utilized to recognize the physical environment or other information and to control the posture and walking of robot system. In order to control the robot precisely, high accuracy of sensor data is required, most of these sensors however, belongs to expensive and low-durable products. Moreover, these are exposed excessive load operation in a field condition if it is applied to field robot system. This issue becomes more serious one when the robot system is manufactured as a mass product. As in this context, this study suggests a virtual sensor technology to alternate or assist the main sensor system. This scheme is realized by using back-propagation algorithm of neural network theory, and the quality of estimated sensor data could be improved through the algorithmic and hardware based treatments. This study performs the various trial to identify the effective parameters which effect to the quality and reliability of estimated sensor data and tries to show the possibility of proposed methodology.

• Advances in aircraft and spacecraft science
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• v.3 no.1
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• pp.15-28
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• 2016

Although the aircraft industry was the first to use fibre composites, now they are increasingly used in a range of structural applications such as flooring, decking, platforms and roofs. Interlayer delamination is a major failure mode which threatens the reliability of composite structures. Delamination can grow in size under increasing loads with time and hence leads to severe loss of structural integrity and stiffness reduction. Delamination reduces the natural frequency and as a consequence may result in resonance. Hence, the study of the effects of delamination on the free vibration behaviour of multilayer composite structures is imperative. The focus of this paper is to develop a 3D FE model and investigate the free vibration behaviour of fibre composite multilayer sandwich panels with interlayer delaminations. A series of parametric studies are conducted to assess the influence of various parameters of concern, using a commercially available finite element package. Additionally, selected points in the delaminated region are connected appropriately to simulate bolting as a remedial measure to fasten the delamination region in the aim of reducing the effects of delamination. First order shear deformation theory based plate elements have been used to model each sandwich layer. The findings suggest that the delamination size and the end fixity of the plate are the most important factors responsible for stiffness reduction due to delamination damage in composite laminates. It is also revealed that bolting the delaminated region can significantly reduce the natural frequency variation due to delamination thereby improving the dynamic performance.