• The Journal of the Korea Contents Association
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• v.14 no.12
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• pp.565-573
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• 2014

We have various e-commerce like on-line banking, stock trading, shopping using a PC or SmartPhone. In e-commerce, two parties use the certificate for identification and non-repudiation but, the attack on the certificate user steadily has been increasing since 2005. The most of hacking is stealing the public certificate and private key files. After hacking, the stolen public certificate and private key file is used on e-commerce to fraud. Generally, the private key file is encrypted and saved only with the user's password, and an encrypted private key file can be used after decrypted with user password. If a password is exposed to hackers, hacker decrypt the encrypted private key file, and uses it. For this reason, the hacker attacks user equipment in a various way like installing Trojan's horse to take over the user's certificate and private key file. In this paper, I propose the management method to secure private key of PKI using One Time Password certification technique. As a result, even if the encrypted private key file is exposed outside, the user's private key is kept safely.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2009.05a
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• pp.109-112
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• 2009

The purpose of this study was to examine the differences in the brain activation evoked by music arranged in major and minor key used with an identical motion film during the fMRI testing. A part of the audio-visual combinations composed by Iwamiya and Sano were used for the study stimuli. This audio- visual clip was originally developed by combining a small motion segment of the animation "The Snowman" and music arranged in both major and minor key from the original jazz music "Avalon" rewritten in a classical style. Twenty-seven Japanese male graduate and undergraduate students participated in the study. Brain regions more activated by the major key than the minor key when presented with the identical motion film were the left cerebellum, the right fusiform gyrus, the right superior occipital, the left superior orbito frontal, the right pallidum, the left precuneus, and the bilateral thalamus. On the other hand, brain regions more activated by the minor key than the major key when presented with the identical motion film were the right medial frontal, the left inferior orbito frontal, the bilateral superior parietal, the left postcentral, and the right precuneus. The study showed a difference in brain regions activated between the two different stimulus (i.e., major key and minor key) controlling for the visual aspect of the experiment. These findings imply that our brain systematically generates differently in the way it processes music written in major and minor key(Supported by the User Science Institute of Kyushu University, Japan and the Korea Science and Engineering Foundation).

• The Journal of Society for e-Business Studies
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• v.17 no.4
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• pp.1-16
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• 2012

Shieh and Wang [10] recently proposed an efficient mutual authentication scheme that combined the cost-effectiveness of operations of Lee et al. [6]. scheme and the security and key agreement of Chen and Yeh scheme. Shieh and Wang [10] scheme, however, does not satisfy the security requirements against a third party (the man-in the middle, attacker) that have to be considered in remote user authentication scheme using password-based smart cards. Shieh and Wang weaknesses are the inappropriateness that it cannot verify the forged message in 3-way handshaking mutual authentication, and the vulnerability that the system (server) secret key can easily be exposed. This paper investigates the problems of Shieh and Wang scheme in the verification procedure of the forged messages intercepted by the eavesdrop. An enhanced two-way remote user authentication scheme is proposed that is safe and strong against multiple attacks by adding the ability to perform integrity check on the server and proposed scheme is not expose user password information and the system's confidential information.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.39 no.4
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• pp.388-398
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• 2002

Video representation through representative frames (key frames) has been addressed frequently as an efficient way of preserving the whole temporal information of sequence with a considerably smaller amount of data. Such compact video representation is suitable for the purpose of video browsing in limited storage or transmission bandwidth environments. In a case like this, the controllability of the total key frame number (i.e. key frame rate) depending on the storage or bandwidth capacity is an important requirement of a key frame selection method. In this paper, we present a sequential key frame selection method when the number of key frames is given as a constraint. It first selects the desired number of initial key frames and determines non-overlapping initial time intervals that are represented by each key frame. Then, it adjusts the positions of key frames and time intervals by iteration, which minimizes the distortion. Experimental result demonstrates the improved performance of our algorithm over the existing approaches.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.6B
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• pp.977-983
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• 2010

In mobile and secure military networks, full-meshed IPSec tunnels, which do correspond to not physical links but logical links between each IPSec device and its peer, are required to provide multicast communications. All IPSec devices need support in changing IPSec tunnels by a way of using a multicast group key which is updated dynamically. Tactical terminals, which often constitute a group, need also secure multicast communications in the same group members. Then, the multicast group key is required to be updated dynamically in order to support group members' mobility. This paper presents challenging issues of designing a secure and dynamic group key management of which concept is based on the Diffie-Hellman (DH) key exchange algorithm and key trees. The advantage of our dynamic tree based key management is that it enables the dynamic group members to periodically receive status information from every peer members and effectively update a group key based on dynamically changing environments.

• Smart Structures and Systems
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• v.26 no.6
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• pp.693-701
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• 2020

The conventional Kalman Filter (KF) provides a promising way for structural state estimation. However, the physical parameters of structural systems or models should be available for the estimation. Moreover, it is not applicable when the loadings applied to the structures are unknown. To circumvent the aforementioned limitations, a two-stage KF with unknown input approach is proposed for the simultaneous identification of structural parameters and unknown loadings. In stage 1, a modified observation equation is employed. The structural state vector is estimated by KF on the basis of structural parameters identified at the previous time-step. Then, the unknown input is identified by Least Squares Estimation (LSE). In stage 2, based on the concept of sensitivity matrix, the structural parameters are updated at the current time-step by using the estimated structural states obtained from stage 1. The effectiveness of the proposed approach is numerically validated via a five-story shearing model under random and earthquake excitations. Shaking table tests on a five-story structure are also employed to demonstrate the performance of the proposed approach. It is demonstrated from numerical and experimental results that the proposed approach can be used for the identification of parameters of structure and the external force applied to it with acceptable accuracy.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.3
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• pp.1785-1801
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• 2017

In recent years, image encryption algorithms have been developed rapidly in order to ensure the security of image transmission. With the assistance of our previous work, this paper proposes a novel chaotic image encryption algorithm based on self-adaptive model and feedback mechanism to enhance the security and improve the efficiency. Different from other existing methods where the permutation is performed by the self-adaptive model, the initial values of iteration are generated in a novel way to make the distribution of initial values more uniform. Unlike the other schemes which is on the strength of the feedback mechanism in the stage of diffusion, the piecewise linear chaotic map is first introduced to produce the intermediate values for the sake of resisting the differential attack. The security and efficiency analysis has been performed. We measure our scheme through comprehensive simulations, considering key sensitivity, key space, encryption speed, and resistance to common attacks, especially differential attack.

• Journal of KIISE:Information Networking
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• v.31 no.2
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• pp.179-187
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• 2004

Password authenticated key exchange protocols for the symmetric model are easier to design, analyze and are more efficient than ones for the asymmetric model, but they are most likely to be broken by server's compromise. Though the protocols with provable security for the asymmetric model such as PAK-X and SNAPI-X are introduced, they need large amount of computation compared with the standard Diffie-Hellman key exchange. We present a systematic and efficient way to transform password authenticated key exchange protocols for the symmetric model into protocols for the asymmetric model. Thus, an efficient protocol for the asymmetric model can be constructed by a systematic protocol with low computation.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.9
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• pp.4242-4263
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• 2017

Multi-User Multiple-Input Multiple-Output (MU-MIMO) technology has recently attracted significant attention from academia and industry because of it is increasingly important role in improving networks' capacity and data rate. Moreover, MU-MIMO systems for the Fifth Generation (5G) have already been researched. High Quality of Service (QoS) and efficient operations at the Medium Access Control (MAC) layer have become key requirements. In this paper, we propose a downlink MU-MIMO MAC protocol based on adaptive Channel State Information (CSI) feedback (called MMM-A) for Wireless Local Area Networks (WLANs). A modified CSMA/CA mechanism using new frame formats is adopted in the proposed protocol. Specifically, the CSI is exchanged between stations (STAs) in an adaptive way, and a packet selection strategy which can guarantee a fairer QoS for scenarios with differentiated traffic is also included in the MMM-A protocol. We then derive the expressions of the throughput and access delay, and analyze the performance of the protocol. It is easy to find that the MMM-A protocol outperforms the commonly used protocols in terms of the saturated throughput and access delay through simulation and analysis results.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.273-278
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• 2001

Since its introduction in mid 1990s, Financial Crisis in Korea, knowledge management (KM) has been considered as a new, optimal way of corporate management style. And a large number of researches, either theoretically or empirically, were carried out in order to find out what the key success factors will be in common. However, though key success factors are extracted, it can hardly be a successful project if those are not well matched for the unique industry characteristics, still more in construction industry. Even we can find some KM precedents in construction industry, it can hardly be revealed how far they exerted themselves in order to match key factors with industry characteristics. Hence, at the dawn of implementing KM, this research work will scrutinize key success factors (KSFs) derived from previous studies and funnel those KSFs into construction domain. Then rearranged KSFs will be proposed with each key issues. Therefore, this article can contribute to setting strategies for KM in construction sector.