• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.05a
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• pp.119-124
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• 2001

A new WDM-based protocol for scheduling a variable-length message is proposed in this paper. Two control slots, Pre-reservation slot and Reservation Slot, are used to coordinate transmission and diminish the collisions of packet to minimize the access delay. When there is an idle reservation slot, a control packet is transmitted on that slot and message is transferred. And the node continues to transmit its control packet through the corresponding slot every cycle, until the message is completely transmitted. If an idle reservation slot is not available, the node schedules the transmission time of message in earliest available time using Pre-reservation slots. The proposed scheduling protocol has several advantages; any new node can join the network anytime without network re-initialization. Moreover, with the pre-reservation slots, we can avoid the packet collisions and destination conflicts, and we can improve the access delay time for message transmissions.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.12A
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• pp.1113-1121
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• 2010

The Vehicle Safety Communications (VSC) is one of VANET applications for preventing vehicle accidents, and it utilizes vehicle-to-vehicle communication to exchange emergency messages. To propagate such messages in VSC, several schemes based on selective flooding have been proposed. Their common idea is that an emergency message is relayed by one of vehicles receiving the message. However, the schemes do not consider the transmission errors and duplications of an emergency event. In the schemes, if there are transmission errors and a vehicle detects a hazard, there may be vehicles which fail to receive an emergency message. If k vehicles detect a hazard, k emergency messages are created and propagated. The duplications of an event increase reliability of the message delivery but decrease efficiency. In this paper, we propose an emergency message delivery scheme which is efficient and robust to transmission errors. Our proposed scheme utilizes clustering for massage aggregation and retransmissions in a cluster. It also uses an acknowledgment mechanism for reliable inter-cluster communication. Our simulation results show that the proposed scheme outperforms Least Common Neighbor Flooding which is one of the selective flooding schemes.

• Journal of KIISE:Information Networking
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• v.29 no.3
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• pp.277-285
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• 2002

This paper proposes and analyzes an error control scheme for the transmission control based real-time communication, such as FDDI, TDMA, and wireless LAN, which delivers the message according to the round robin fashion after the off-line bandwidth allocation. Taking into account the time constraint of each message, the proposed error control scheme makes the receiver transmit the error report via asynchronous traffic while the sender resend the requested message via overallocated access time which is inevitably introduced by the bandwidth allocation procedure for hard real -time guarantee. The error control procedure does not interfere other real -time message transmissions. In addition, as each frame contains the size of the message it belongs, the receiver can recognize the end of completion of message transmission. This enables earlier error report to the receiver so that the sender can cope with more network errors. The analysis results along with simulation performed via SMPL show that the proposed scheme is able to enhance the deadline meet ratio of messages by overcoming the network errors. Using the proposed error control scheme, the hard real -time network can be built at cost lower than, but performance comparable to the expensive dual link network.

• Management & Information Systems Review
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• v.31 no.4
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• pp.639-661
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• 2012

The purpose of the paper is to examine sidedness effects of comparative advertising and moderating roles of the emotions of customer and product type. To test the research hypotheses, this study conducted experimental designs. One hundred ninety-two undergraduate students were assigned to one of the four experimental groups. Comparative Advertising message type and product type were manipulated as between-subject factors. There was a surprising event situation(free gift event) when participants came to laboratory for experiment, which is for the emotion manipulation. If a participant in a positive emotion group, he or she gets a free gift. The data demonstrate that comparative message type have a significant effect on both attitude toward the advertising and acceptance intention. In addition, consumers' emotion and product type play a significant moderating role between the message types and the dependent variables. The results of this study contribute to the literature as a new attempt to examine the sidedness effect of the comparative advertising message. We suggested that message types and consumer's emotion is one of very important aspects for a comparative advertising and marketers should consider people's emotion when they release a comparative advertising, which can help when marketers make their strategy for a comparative advertising.

• The KIPS Transactions:PartD
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• v.12D no.5 s.101
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• pp.781-788
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• 2005

MTF message is the normalized and standardized format which is used in the time when it tries to transmit data to other systems or exchanges needed information in defense message systems. XML can support variety of search functionality and is estimated to be the best way from the view of efficient presentation and exchange in internet based environment, based on advantage which is independent of hardware and software. US army brought in XML-MTF combining with XML based technology, but we do not contain such a MTF system, and necessity of MTF is increasing for combined operation between ROK and US as a lot of C4I system were transferred to Web based systems. In this paper, we make analysis of fundamental structure, organization of paragraph, witting regulation of MTF message. We present the rule of naming element and fundamental mapping rule for transformation of its XML based on it. Also, we prove that MTF message can be transformed to XML document by trying to transforming sample documents to XML document applying presented mapping rule, creating MTF message based on it and implement program which can automatically transform them to XML-MTF.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.7 no.3
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• pp.41-52
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• 1997

In this paper, we analyze two claws of Zhou-Gollmann's protocol. The protocol divide the message into a key K and a ciphertext C. The ciphertext C is delivered to the recipient, but the key K is submitted to the TTP, after the message originator receive the recipient's receipt for the ciphertext. TTP puts the key in the directory which is accesaible to the public. So, the recipient's obtaining the message dependson whether the originator submits the key or not. We will show that the originator. which is in such an advantageous position, could make the protocol be unfair and present how to improve the protocol. On the other hand, Zhou-Gollmann's protocol doesn't provide the secrecy of the message, since the key K is published. This means that, to send a secret message, additional mechanism is required. In this paper, we will present an improvement of Zhou-Gollmann's protocol to keep the message secret. The key distribution of the proposed protocol is based on the Diffie-Hellman's one.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.32 no.2
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• pp.255-266
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• 2022

Messenger applications applied end-to-end encryption on their own to prevent message exposure to servers. Standardization of a group messaging protocol called Message Layer Security (MLS) with end-to-end encryption is being discussed for secure and efficient message communication. This paper performs safety checks based on the operation process and security requirements of MLS. Confidentiality to a middleman server, which is an essential security requirement in messenger communication, can be easily violated by a server administrator. We define a server administrator who is curious about the group's communication content as a curious admin and present an attack in which the admin obtains a group key from MLS. Reminds messenger application users that the server can view your communication content at any time. We discuss ways to authenticate between users without going through the server to prevent curious admin attacks.

• Journal of KIISE
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• v.44 no.8
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• pp.860-869
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• 2017

Recently, due to the personal information security act, the encryption of personal information has attracted attention. However, if the conventional encryption scheme is used directly, the database schema must be changed because the conventional encryption scheme does not preserve the format of the data, which can yield a large cost. Therefore, the Format-Preserving Encryption(FPE) has emerged as an important technique that ensures the confidentiality of the data and maintains the database schema naturally. Accordingly, National Institute of Standards and Technology(NIST) recently published the FF1 and FF3 as standards for FPE, although problems have been found in the security of FF1 and FF3 against message recovery attacks. In this paper, we study and analyze FF1 and FF3 as the standards of FPE, as well as the message recovery attack on these schemes. We also study a secure FPE against message recovery attack and verify the efficiency by implementing standardized FF1 and FF3.

• Journal of KIISE:Information Networking
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• v.27 no.2
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• pp.149-159
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• 2000

In mobile computing environments, invalidation and propagation method based on broadcasting is used to transmit the information for cache maintenance of mobile hosts. Previous researches generally adopted invalidation method that easily adapts to the limited network bandwidth and the frequent disconnection. But the invalidation of frequently accessed data causes the contention on the wireless network with the increasing cache requests. Although the propagation method can reduce the cache requests, the high probability of broken message or loss of message is the main factor that degrades the system performance. To resolve these problems, we propose adaptive cache maintenance scheme that dynamically adjusts the broadcasting ratio of invalidation and propagation, according to the wireless network connection states. The proposed scheme broadcasts the propagation message in stable connection state, so it can reduce the cache requests and server response time. With the decreasing available network bandwidth by the frequent partial disconnection and disconnection, the proposed scheme dynamically increases the broadcasting ratio of the invalidation messages to minimize the broken message or the loss of message probability. Consequently, the proposed scheme resolves the problems which arise in the invalidation or propagation method in mobile computing environments.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.3B
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• pp.526-535
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• 2010

In this paper, we propose the fault-tolerant network-based mobility management scheme for supporting multimedia services of broadcasting & communications convergence in fixed mobile convergence (FMC) networks. The proposed scheme is based on AIMS (Access Independent Mobility Service) which is developed for the mobility support among heterogeneous access networks. To support stable location management and handover control for a MN, the proposed scheme supports stable management of binding information by sensing network attachment and detachment of a mobile node (MN). In addition, the proposed fault-tolerant (FT) AIMS supports a function of message retransmission for the support of handover control message and a function of heartbeat message transmission for the support of stable access network environments to a mobile node. We evaluate and analyze the performance of the proposed scheme through the implementation of AIMS system test-bed.