• Journal of the Korea Society for Simulation
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• v.9 no.3
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• pp.65-75
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• 2000

In recent years, significant advances in computers and communication technologies have made multimedia services feasible. As a result, various queuing models and cost models on architecture and data placement for multimedia server have been proposed. However, these analytical techniques use only probabilistic models to represent the behavior of a system, and then they have several limitations like accuracy. Simulation is a viable alternative to analytical model. It avoids many of the limitations associated with analytical techniques, allowing for more precise representation of system attributes like workload in program code. In this paper, we propose a simulation test bed that can evaluate performance of real-time multimedia server by using simulation model.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.8
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• pp.669-672
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• 2004

This paper considers the implementation and experiments of an open-loop Cylindrical Vibratory Gyroscope(CGV). An open-loop CGV composed of thin cylindrical vibrating element, electromagnetic drive and pick-off element with open-loop control was designed and fabricated. The experimental performance tests of the open-loop CGV were done using a temperature chambered rate table. Also, the limitations of open-loop CGV were analyzed and the solution for the limitations was proposed.

• Proceedings of the Korea Information Processing Society Conference
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• 2014.04a
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• pp.606-607
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• 2014

Due to Web Services' platform and language independent nature, many business corporations have used them for the integration of various applications. However, the growing amount of available Web Services on Web forms a new problem - how to select and recommend an appropriate Web Service that matches the user requirements. In this paper, we investigate recommendation methods in Web Services, and discuss their strength and limitations.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.918-919
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• 2012

Web Services have been used in a variety of applications and have become a key technology in developing business operations on the Web. However, despite the growing use of Web Services by large corporations, security is still a major concern that is slowing their deployment. In this paper, we give an overview of security vulnerabilities, review the existing solutions, and show their limitations.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.11a
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• pp.1469-1472
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• 2008

Honeynets have become one of essential tools in system and network security. As the importance of security has increased over the years, many researchers try to improve the overall Honeynet architecture. Due to their efforts, the Honeynets have evolved up to the third generation. However, the GenIII architecture has some limitations. In this paper, we address some of the limitations and provide solutions by redesigning the framework of data capture of Honeynets.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.11a
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• pp.95-96
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• 2023

The purpose of this study is to derive the limitations of the existing management system by analyzing the characteristics of the PC process to improve the PC construction project management system process. To overcome the limitations derived, we present a process of managing integrated information from the design-production-construction stage using QR codes and clouds. This is expected to help develop a PC construction project management system.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.10a
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• pp.797-803
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• 2009

The accurate prediction of dynamic characteristics of high speed rotors, such as gas turbines, is important to avoid the possibility of operating the machinery near the critical speeds or unstable speed regions. However, the dynamic analysis methods and softwares for gas turbines have been developed in the process of producing many gas turbines by manufacturers and most of them have seldom been disclosed to the public. Recently, commercial FEM softwares, such as SAMCEF, ANSYS and NASTRAN, started supporting some rotordynamics analysis modules based on 3-D finite elements. In this paper, the dynamic analysis method using commercial S/W, especially ANSYS, is attempted for the small-size gas turbine engine rotor, and the analysis capability and limitations of its rotordyamics module are evaluated for further improvement of the module. As the preliminary procedure, the rotordyamic analysis capability of ANSYS was tested and evaluated with the reference models of the well-known dynamics. The limitations in application of the rotordynamics module were then identified. Under the current capability and limitations of ANSYS, it is shown that Lee diagram, a new frequency-speed diagram enhanced with the concept of $H{\infty}$ in rotating machinery, can be indirectly obtained from FRFs computed from harmonic response analysis of ANSYS. Finally, it is demonstrated based on the modeling and analysis method developed in the process of the S/W verification that the conventional Campbell diagram, Lee diagram, mode shapes and critical speeds of the small-size gas turbine engine rotor can be computed using the ANSYS rotordynamics module.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.1
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• pp.36-44
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• 2010

The accurate prediction of dynamic characteristics of high speed rotors, such as gas turbines, is important to avoid the possibility of operating the machinery near the critical speeds or unstable speed regions. However, the dynamic analysis methods and softwares for gas turbines have been developed in the process of producing many gas turbines by manufacturers and most of them have seldom been disclosed to the public. Recently, commercial FEM softwares, such as SAMCEF, ANSYS and NASTRAN, started supporting some rotordynamics analysis modules based on 3-D finite elements. In this paper, the dynamic analysis method using commercial S/W, especially ANSYS, is attempted for the small-size gas turbine engine rotor, and the analysis capability and limitations of its rotordyamics module are evaluated for further improvement of the module. As the preliminary procedure, the rotordyamic analysis capability of ANSYS was tested and evaluated with the reference models of the well-known dynamics. The limitations in application of the rotordynamics module were then identified. Under the current capability and limitations of ANSYS, it is shown that Lee diagram, a new frequency-speed diagram enhanced with the concept of $H{\infty}$ in rotating machinery, can be indirectly obtained from FRFs computed from harmonic response analysis of ANSYS. Finally, it is demonstrated based on the modeling and analysis method developed in the process of the S/W verification that the conventional Campbell diagram, Lee diagram, mode shapes and critical speeds of the small-size gas turbine engine rotor can be computed using the ANSYS rotordynamics module.

• Journal of Digital Convergence
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• v.12 no.2
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• pp.563-570
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• 2014

As information security is becoming more important today, efforts in managing information security more efficiently is becoming greater. Each department such as Ministry of Security and Public Administration, Ministry of Science, Ministry of Education, National Intelligence Service, etc. is established screening criteria for information security and conducted the evaluation. Various information security certification and evaluation for public institutions effectively help to improve the level of information security. However, there are limitations of efficient security management because the examination to be performed frequently by each department. In this paper, we analyze screening criteria of the information security management that is being conducted in the public institutions. We also present limitations of information security management and the direction of improving the limitations.

• Women's Health Nursing
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• v.8 no.1
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• pp.96-105
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• 2002

The purpose of this study is to identify the relation between functional limitation, functional disability and back pain during pregnancy. Data was collected by interview or self-report from 66 pregnant women between the gestational ages of 17 and 22 weeks who had experienced back pain from February 17 through July 28, 2001. The results of this study are as follows; 1. The prevalent mean week of back pain starting during pregnancy was 12.8. The mean pain intensity scores on the VAS during the past week and now were 5.6 and 3.7. The mean score on the functional limitations was 38.9. The mean score on the functional disability was 19.7. 2. The pain intensity on the past week was correlated with the pain intensity now (r=.339, p<0.01) and the functional limitations (r=.251, p<0.05). The pain intensity now was correlated with the functional limitations (r=.295, p<0.05) and the functional disability (r=.429, p<0.01). The functional limitations was correlated with the functional disability (r=.229, p<0.01). The higher pain intensity was the more functional limitation and functional disability occurred. 3. There was a statistically significant correlation between the pain intensity now and the type of housing (t=-2.051, p=.045), and back pain history before pregnancy (t=-2.429 p=.003). 4. There was a statistically significant correlation between the functional limitation and income (F=2.803, p=.047) and back pain history before pregnancy (t=-3.225, p=.002). There was a statistically significant correlation between the functional disability and back pain history before pregnancy (t=-3.058 p=.003). In conclusion, we found that a history of back pain was an important factor when predicting back pain and functional disability and limitation during pregnancy. The nurse and the prenatal educator should detect risk factors of back pain early in pregnancy and manage continuously though pregnancy.