• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.177-183
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• 2008

For 10 kW-class Stirling engine using scroll expander and scroll compressor, considerations on thermal expansion of the fixed and orbiting scroll members of the scroll expander due to high gas temperature at the expander inlet has resulted in adopting of the keys between the fixed scroll and main frame for the fixed scroll side and spring type insertion between the orbiting scroll base plate and supporting holders for orbiting scroll side. Dynamic analysis on the fixed and orbiting scroll members and the shafts of the scroll expander showed that using of these devices for complying thermal expansion caused large variations of the forces acting on the fixed scroll keys and on the power transmitting shafts and also on the shaft bearings.

• Journal of Ecology and Environment
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• v.29 no.5
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• pp.425-432
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• 2006

The tadpoles of 12 Korean anuran species, including Bombina orientalis, Bufo gargarizans, B. stejnegeri, Hyla japonica, Kaloula borealis, Rana dybowskii, R. huanrenensis, R. coreana, R. nigromaculata, R. chosenica, R. rugosa, and R. catesbeiana, were classified based on their morphological characteristics. We collected eggs or tadpoles of the 12 Korean anuran species from Gangwon, Incheon, Chungcheong, and Gyeonggi districts in 2005 and 2006 breeding seasons. When the tadpoles reached at $27{\sim}37$ Gosner's developmental stages, we described morphological characteristics of the tadpoles of each anuran species and measured their physical parameters such as total length, body length, and body mass. After that, we chose 12 morphological characteristics to identify each species and to use them as classification keys such as eye location, caudal musculature pattern, spiracle location, oral disc morphology, and labial tooth row formula. In this paper, we presented classification keys, morphological characteristics, and drawings for the tadpoles of 12 anuran species.

• IE interfaces
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• v.20 no.4
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• pp.539-546
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• 2007

This study has been conducted on touch screen interface design for mobile devices. It was intended to measure user’s satisfaction on one-handed thumb input mobile devices. Recent studies proposed the optimal touch button size, but it is inappropriate for mobile devices. Therefore, this study was focused on four touch key factors-width, height, the horizontal and vertical distance between touch keys-as independent variables. The ANOVA results showed that the user satisfaction of four touch key factors was significantly affected by the thumb input. It also apparent that the interactions between four factors were significant. As a result, the horizontal and vertical distance as well as the width and height affected the satisfaction of users. In addition, this study suggested satisfaction models which represent the top 30%, 50%, 70% of user satisfaction measurement. The results of this study could be used to design touch keys that are able to enhance the usability on touch screen based mobile devices.

• ETRI Journal
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• v.28 no.3
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• pp.375-378
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• 2006

This letter presents a pairwise key establishment scheme that is robust against the compromise of nodes in mobile ad hoc networks. Each node establishes local keys with its neighbor nodes that are at most three hops away at network boot-up time. When any two nodes establish a pairwise key, they receive the secret information from the nodes on the route between them, and construct the pairwise key using the secret information. Here, the local keys are utilized by the nodes on the route to send the secret information securely. The simulation results have proven that the proposed scheme provides better security than the key pre-distribution-based scheme.

• Animal cells and systems
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• v.3 no.1
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• pp.59-68
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• 1999

Chthamalus challengeri Hoek was collected from intertidal rocks to rear the larvae from hatching through nauplius to cyprid in the laboratory. Larval development consists of six nauplius stages and a cyprid. Unilobed labrum with a prominent protuberance and the frontolateral horns folded under the anterior cephalic shield margin are diagnostic features through all nauplius stages. The posterior border of the cephalic shield bears no posterior shield spines in nauplius stages IV-Ⅵ. There is a specific hispid seta in the fourth group of the antennal endopodite. Morphological features such as the cephalic shield, labrum, abdominal process, antennules, antennae and mandibles in all nauplius and cyprid stages are illustrated and described. The numerical setations of the antennule are found to aid in the intraspecific identification of barnacle nauplius stages without dissection. The keys to each stage of the barnacle larvae in Korean coastal waters are provided based on the reared nauplii of seven species: Pollicipes mitella Octomeris sulcata, Chthamalus challengeri, Balanus albicostatus B. trigonus, B. amphitrite, and B. improvisus inhabiting Korean coastal waters.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.8
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• pp.1186-1192
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• 2012

In Jeju Smart Grid field test, Zigbee technology is being used as one of customer side solutions for AMI. Although Zigbee networks that provides effective connectivity and control among devices are advantages in ease of implementation and use, the data can be exposed to cyber attacks such as eavesdrop, unauthorized data dissemination and forgery. Currently authentication and confidentiality services are provided with the network and link keys generated based on public key pairs that are pre-installed in offline. However, the network is vulnerable once a hacker intrudes into a local network because operation and management policies for the generated keys are not well-established yet. In this paper, the vulnerability of the Zigbee security system in the customer side environment of Jeju Smart Grid field test is analyzed. Then, two-way authentication with the unique identifiers of devices and user-specific group management policies are proposed to resolve the vulnerability.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.1
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• pp.101-103
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• 2016

We propose a HTTP cookie-based identification of the public keys of Web sites for the case of failure to validate certificates. The proposed scheme effectively protects users from the phishing attacks of inducing them to access bogus sites. It incurs little performance overhead on the browser and the server of Web sites. It requires to implement the input processing of user credentials and the encryption and verification of cookie values, though.

• Journal of Sensor Science and Technology
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• v.24 no.2
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• pp.107-112
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• 2015

HIGHT is an 64-bit block cipher, which is suitable for low power and ultra-light implementation that are used in the network that needs the consideration of security aspects. This paper presents a parallel key scheduler that generates the whitening keys and subkeys simultaneously for both encryption and decryption processes. We construct the reverse LFSR and key generation blocks to generate the keys for decryption process. Then, the new key scheduler is made by sharing the common logics for encryption and decryption processes to minimize the increase in hardware complexity. From the simulation results, the logic size is increased 1.31 times compared to the conventional HIGHT. However, the performance of HIGHT including the proposed key scheduler can be increased by two times compared to the conventional counterpart.

• Journal of the military operations research society of Korea
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• v.26 no.1
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• pp.115-124
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• 2000

In this paper, we are introduced a certification system for open network environment. The Kerberos which was developed by MIT uses a secret key cryptosystem for authentication. It is secure and efficient for closed network users to authenticate each others. However, the kerberos has a disadvantage of managing a lot of secret keys for In this paper, we are introduced a certification system for open network environment. users in the open network environment. This paper suggests a method that uses X.509 to provide public keys with certification to Kerberos users for authentication in the X.500 directory standard. And we also suggest the smartcard as data storage device to enhance the security and availability.

• Journal of Korea Multimedia Society
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• v.20 no.5
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• pp.782-790
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• 2017

As most of the recent smart devices have NFC function the NFC mobile coupon will become one of the pervasive NFC applications. We need the secure NFC coupon protocols to issue and use NFC mobile coupon. In this paper, we analyze the security of the previous protocols and point out the problems of security. As the result of analysis, Premium M-coupon Protocol proposed by A. Alshehri and S. Schneider is the most secure but has unnecessary operations. We propose the Modified Premium M-coupon Protocol-1 with the unnecessary operations removed and show this protocol is secure by security analysis. Most of NFC mobile coupon protocols use the cryptography with the shared secret keys. We propose the Modified Premium M-coupon Protocol-2 without the shared secret keys and show this protocol is secure by security analysis.