• Nuclear Engineering and Technology
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• v.53 no.9
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• pp.2977-2981
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• 2021

Corrosion fatigue crack growth (FCG) behavior of 316LN stainless steel was investigated in high-temperature pressurized water at different temperatures, load ratios (R = K_max/K_min) and rise times (t_R). The environmental assisted effect on FCG rate was observed when both the R and t_R exceeded their critical values. The FCG rate showed a linear relation with stress intensity factor range (ΔK) in double logarithmic coordinate. The environmental assisted effect on FCG rate depended on the ΔK and quantitative relations were proposed. Possible mechanisms of environmental assisted FCG rate under different testing conditions are also discussed.

• Korean Journal of Optics and Photonics
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• v.15 no.2
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• pp.114-122
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• 2004

In this paper, we proposed an optical encryption and decryption technique that uses a nail bed pattern as a key-code. Since the technique uses a nail bed pattern that is a biometric signal of an encryptor, the technique is robust about a fake key or illegal use of a key. In addition to this, the encrypted image contains the biometric information of the encryptor. This makes the proposed technique also be applied to authentication.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.7
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• pp.1367-1372
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• 2007

This paper suggests One-time Password key exchange authentication technique for a strong authentication based on MANET and through identify wireless environment security vulnerabilities, analyzes current authentication techniques. The suggested authentication technique consists of 3 steps: Routing, Registration, and Running. The Routing step sets a safe route using AODV protocol. The Registration and Running step apply the One-time password S/key and the DH-EKE based on the password, for source node authentication. In setting the Session key for safe packet transmission and data encryption, the suggested authentication technique encrypts message as H(pwd) verifiers, performs key exchange and utilizes One time password for the password possession verification and the efficiency enhancement. EKE sets end to end session key using the DH-EKE in which it expounds the identifier to hash function with the modula exponent. A safe session key exchange is possible through encryption of the H(pwd) verifier. The suggested authentication technique requires exponentiation and is applicable in the wireless network environment because it transmits data at a time for key sharing, which proves it is a strong and reliable authentication technique based on the complete MANET.

• Nuclear Engineering and Technology
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• v.56 no.5
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• pp.1887-1894
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• 2024

Fatigue strength of the structural materials of lead-cooled fast reactors (LFRs) and accelerator-driven systems (ADS) may be degraded in liquid metal (Lead or lead-bismuth eutectic (LBE)) environments. The fatigue crack growth (FCG) data of structural materials in liquid LBE are necessary for damage tolerance design, safety assessment and life management of key equipment. A novel monitoring system for fatigue crack length was designed on the compliance method and the monitor technology of crack opening displacement (COD) of CT specimens by the linear variable differential transformers (LVDT) system. It can be used to predict the crack length by monitoring the COD of CT specimens in harsh high-temperature liquid LBE using a LVDT system. The prediction accuracy of this system was verified by FCG experiments in room temperature air and liquid LBE at 150, 250 and 350 ℃. The first results obtained in the FCG test for T91 steel in liquid LBE at 350 ℃ are presented.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.10
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• pp.1822-1828
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• 2006

A key-frame should be efficiently selected to distinguish bad information from the videos. A previous technique selecting a key-frame mostly consists of the transformation scene-centered. In the case of harmful videos containing the quaility of continuous changes, the technique makes the total rate be reduced by an unnecessary key-frame. This thesis suggests the technique selecting a key-frame, an entry of the distinguishing system by using the quality of changes between the frames. In the experiment of this technique, it was proved that over 90% of the bad information was distinguished by the selected key frame, and also time efficiency was proved by showing 68% of decrement compared to the numbers I-frame. Therefore, This technique makes the system efficient to distinguish bad information, and efficiently can contribute to the distribution of the healthy movie information.

• IEMEK Journal of Embedded Systems and Applications
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• v.6 no.3
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• pp.168-173
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• 2011

In this paper, an optical image hiding technique using real-valued decoding key is proposed. In the embedding process, a each zero-padded original image placed in a quadrants on an input plane is multiplied by a statistically independent random phase pattern and is Fourier transformed. An encoded image is obtained by taking the real-valued data from the Fourier transformed image. And then a phase-encoded pattern, used as a hidden image and a decoding key, is generated by the use of multiple phase wrapping from the encoded images. A transmitted image is made from the linear superposition of the weighted hidden images and a cover image. In reconstruction process, the mirror reconstructed images can be obtained at two quadrants by the inverse-Fourier transform of the product of the transmitted image and the decoding key. Computer simulation and optical experiment are demonstrated in order to confirm the proposed technique.

• Journal of Korea Society of Digital Industry and Information Management
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• v.13 no.4
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• pp.115-123
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• 2017

The mutual cooperation among nodes is very important because mobile nodes participating in MANET communicate with limited resources and wireless environment. This characteristic is important especially in environment that supports group communication. In order to support the secure multicast environment, it is important enough to affect performance to provide accurate authentication method for multicast group members and increase the integrity of transmitted data. Therefore, we propose a technique to provide the multicast secure communication by providing efficient authentication and group key management for multicast member nodes in this paper. The cluster structure is used for authentication of nodes in the proposed technique. In order to efficient authentication of nodes, the reliability is measured using a combination of local trust information and global trust information measured by neighboring nodes. And issuing process of the group key has two steps. The issued security group key increases the integrity of the transmitted data. The superiority of the proposed technique was confirmed by comparative experiments.

• Convergence Security Journal
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• v.20 no.5
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• pp.33-39
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• 2020

In MANET consisting of only mobile nodes, all nodes serve as routes. However, the dynamic topology due to frequent movement of nodes degrades routing performance and is also cause of many security vulnerabilities. Therefore, security must be applied to routing techniques that can influence the performance of MANET. In this paper, we propose a technique for efficiently responding to various routing attacks and safe data transmission through application of zone-key based security routing techniques. A zone-based network structure was used, and a management node that manages member nodes in each zone was used in the proposed technique. In addition, the damage from the attacking node was minimized by issuing a key to each node and applying this to a routing technique. The zone management node issues a key for encryption routing information and manages the issuance information. A member node that wants to transmit data encrypts routing in formation using a key issued from the zone management node, and then performs path discovery using this. The improved performance of the proposed technique was confirmed through a comparative experiment with the CBSR and ARNA technique, excellent performance was confirmed through experiments.

• Journal of KIISE
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• v.43 no.2
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• pp.143-151
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• 2016

Data deduplication is an important technique for cloud storage savings. These techniques are especially important for encrypted data because data deduplication over plaintext is basically vulnerable for data confidentiality. We examined encrypted data deduplication with the aid of a key issuing server and compared Convergent Encryption with a technique created by M.Bellare et al. In addition, we implemented this technique over not only Dropbox but also an open cloud storage service, Openstack Swift. We measured the performance for this technique over Dropbox and Openstack Swift. According to our results, we verified that the encrypted data deduplication technique with the aid of a key issuing server is a feasible and versatile method.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.6
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• pp.1462-1470
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• 2013

This paper proposes an SWAD-KNH(Sybil & Wormhole Attack Detection using Key, Neighbor list and Hop count) technique which consists of an SWAD(Sybil & Wormhole Attack Detection) module detecting an Worm attack and a KGDC(Key Generation and Distribution based on Cluster) module generating and an sense node key and a Group key by the cluster and distributing them. The KGDC module generates a group key and an sense node key by using an ECDH algorithm, a hash function, and a key-chain technique and distributes them safely. An SWAD module strengthens the detection of an Sybil attack by accomplishing 2-step key acknowledgement procedure and detects a Wormhole attack by using the number of the common neighbor nodes and hop counts of an source and destination node. As the result of the SWAD-KNH technique shows an Sybil attack detection rate is 91.2% and its average FPR 3.82%, a Wormhole attack detection rate is 90%, and its average FPR 4.64%, Sybil and wormhole attack detection rate and its reliability are improved.