• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.1
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• pp.149-165
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• 2013

Current group key agreement protocols, which are often tree-based, have unnecessary delays that are caused when members with low-performance computer systems join a group key computation process. These delays are caused by the computations necessary to balance a key tree after membership changes. An alternate approach to group key generation that reduces delays is the dynamic prioritizing mechanism of queue-based group key generation. We propose an efficient group key agreement protocol and present the results of performance evaluation tests of this protocol. The queue-based approach that we propose is scalable and requires less computational overhead than conventional tree-based protocols.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.7
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• pp.1737-1753
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• 2013

Current group key agreement protocols, which are often tree-based, have unnecessary delays that are caused when members with low-performance computer systems join a group key computation process. These delays are caused by the computations necessary to balance a key tree after membership changes. An alternate approach to group key generation that reduces delays is the dynamic prioritizing mechanism of queue-based group key generation. We propose an efficient group key agreement protocol and present the results of performance evaluation tests of this protocol. The queue-based approach that we propose is scalable and requires less computational overhead than conventional tree-based protocols.

• Journal of Power Electronics
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• v.16 no.2
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• pp.584-597
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• 2016

This paper focuses on an improvement in the transient performance of Boost converters when the load changes abruptly. This is achieved on the basis of the nature trajectory in Boost converters. Three key aspects of the transient performance are analyzed including the storage energy change law in the inductors and capacitors of converters during the transient process, the ideal minimum voltage deviation in the transient process, and the minimum voltage deviation control trajectory. The changing relationship curve between the voltage deviation and the recovery time is depicted through analysis and simulations when the load suddenly increases. In addition, the relationship curve between the current fluctuation and the recovery time is obtained when the load suddenly decreases. Considering the aspects of an increasing and decreasing load, this paper proposes the transient performance synthetic optimized trajectory and control laws. Through simulation and experimental results, the transient performances are compared with the other typical three control methods, and the ability of proposed synthetic trajectory and control law to achieve optimal transient performance is verified.

• Journal of Information Display
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• v.13 no.2
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• pp.83-89
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• 2012

The crosstalk evaluation of multiview autostereoscopic three-dimensional (3D) displays is discussed, with both the human and technical factors investigated via image quality assessment. In the imaging performance measurements and analysis for a multiview autostereoscopic display prototype equipment, it was inferred that crosstalk would have both a positive and a negative effect on the imaging performance of the equipment. The importance of the attached diaphragm in the crosstalk evaluation was proposed and then experimentally verified, using the developed prototype equipment. The luminance distribution and crosstalk situation were given, with two different diaphragm arrays applied. The analysis results showed that the imaging performance of this 3D display system can be improved with minimum changes to the system structure.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.7A
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• pp.955-963
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• 1999

In this paper, in other to analyze the performance of efficient key distribution protocol, we evaluate the key distribution processing method of push model like the Kerberos and pull model such as X.9.17 used in wired network. Also, we evaluate the procedure of key distribution protocol in satellite network. Besides, we analyze the performance of key distribution protocol procedure in view of delay and throughput in the case that key distribution protocol is processed based on Inband/Outband channel.

• Industrial Engineering and Management Systems
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• v.7 no.3
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• pp.214-227
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• 2008

Today's dynamic competitiveness requires an organization to improve its performance measurement and management. Quality Management Systems (QMS) abound, the main ones being: ISO series, Malcolm Baldridge National Quality Award (MBNQA), European Forum for Quality Management (EFQM), Six Sigma Business Scorecard and the Balanced Scorecard. Based on the literature, the IPMMM (Integrated Performance Measurement and Management Model) identified 7 key synthesized factors: leadership, strategy management and policy, customer and market, learning and growth, partnership and resources, internal processes and business results that are employed to investigate the key performance indicators of a car assembler using the Delphi methodology. In the 2 rounds of Delphi panels consisting of 20 senior management personnel, the $1^{st}$ round of 198 indicators in the IPMMM yielded 90 indicators. The $2^{nd}$ round yielded 43 performance indicators with 18 rated as critical based on the % assigned in the $1^{st}$ and $2^{nd}$ priority rating of "very important factor" and "key performance indicator" that must be ranked high on both of the priorities. The very critical indicators appeared to be: defect percentage and first time capability (tie in $1^{st}$ place) and revenue, goal setting, customer satisfaction index, on-time delivery, brand image, return on investment, Claim Occurrence Ratio, and debt being ranked from $3^{rd}$ to $10^{th}$. It can be surmised that an organization can identify and develop an appropriate set of performance indicators through the Delphi methodology and implement and manage them based on the Balanced Scorecard.

• The Journal of Society for e-Business Studies
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• v.18 no.3
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• pp.125-142
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• 2013

As a reinforcing strategic-alignment of IT business, Financial Service becomes more rely on IT systems. It needs to continuous information security activities to provide a secure and reliable finance service. Performance measurement of information security activities can be useful for decision and management support. The purpose of this study is to derive CSF(Critical Success Factor) and KPI(Key Performance Indicator) based on K-ISMS, Financial IT Information Security Standards. Providing a rationale can be used to determine key performance indicators, which are utilized as basic data for establishing security policies for financial IT security competency.

• Proceedings of the IEEK Conference
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• 2001.06c
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• pp.55-58
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• 2001

In this paper, we present the development of a JavaCard for public key crypto algorithms and its performance evaluation. To make a high performance for the public key crypto algorithm such as RSA and ECC on a JavaCard, we have implemented a crypto coprocessor in hardware and ported it to the card operating system and virtual machine environments. The performance of the public key crypto algorithms on the JavaCard shows that our JavaCard is suitable for If card applications which needs high performance and high level of security.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.11
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• pp.2769-2792
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• 2013

In this paper, we propose an authenticated key agreement scheme, TinyIBAK, based on the identity-based cryptography and bilinear paring, for large scale sensor networks. We prove the security of our proposal in the random oracle model. According to the formal security validation using AVISPA, the proposed scheme is strongly secure against the passive and active attacks, such as replay, man-in-the middle and node compromise attacks, etc. We implemented our proposal for TinyOS-2.1, analyzed the memory occupation, and evaluated the time and energy performance on the MICAz motes using the Avrora toolkits. Moreover, we deployed our proposal within the TOSSIM simulation framework, and investigated the effect of node density on the performance of our scheme. Experimental results indicate that our proposal consumes an acceptable amount of resources, and is feasible for infrequent key distribution and rekeying in large scale sensor networks. Compared with other ID-based key agreement approaches, TinyIBAK is much more efficient or comparable in performance but provides rekeying. Compared with the traditional key pre-distribution schemes, TinyIBAK achieves significant improvements in terms of security strength, key connectivity, scalability, communication and storage overhead, and enables efficient secure rekeying.

• Journal of the Ergonomics Society of Korea
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• v.29 no.4
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• pp.605-610
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• 2010

In order to design a touch interface for the elderly, human performance of input tasks on the touch screen was investigated by the laboratory experiment. Input times and input errors were measured in the experimental conditions that were changed according to age, key size, interkey space and input tool(finger or stylus pen). In the most of all experimental conditions, the task performance of the elderly was lower than that of the young. However, there were significantly different performance patterns between both groups. As the difficulty of task was getting higher, the task performance of the elderly was sharply decreased; pressing small key button by finger sharply increased input time and error rate, compared to that of the young. Therefore, the square key size suitable to the elderly may be over $8.0{\times}8.0mm$. While the interkey space did not influence to the input task performance of the young, the task performance of the elderly was influenced. The elderly showed big difference of task performance according to input tool. However, the young were less influenced by input tool.