• Phonetics and Speech Sciences
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• v.12 no.1
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• pp.43-50
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• 2020

This study investigated whether listeners' perceptual patterns varied according to base token selected for stimuli manipulation. Voice onset time (VOT) and fundamental frequency (F0) values were orthogonally manipulated, each in seven steps, using naturally produced words that contained a lenis (/kan/) and an aspirated (/k^han/) stop in Seoul Korean. Both native and non-native groups showed significantly higher numbers of aspirated responses for the stimuli constructed with /k^han/, evidencing the use of minor cues left in the stimuli after manipulation. For the native group the use of the VOT and F0 cues in the stop categorization did not differ depending on whether the base token included the lenis or aspirated stop, indicating that the results of previous studies remain tenable that investigated the relative importance of the acoustic cues in the native listener perception of the Korean stop contrasts by using one base token for manipulating perceptual stimuli. For the non-native group, the use patterns of the F0 cue differed as a function of base token selected. Some findings indicated that listeners used alternative cues to identify the stop contrast when major cues sound ambiguous. The use of the manipulated VOT and F0 cues by the non-native group was not native-like, suggesting that non-native listeners may have perceived the minor cues as stable in the context of the manipulated cue combinations.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10a
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• pp.618-622
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• 1990

In this study LLC and MAC program, which is the base of the communication software, is implemented. This program is tested in the MAP board for IBM PC. The LLC is of class 3, which provides the services of type 1 and 3. The MAC uses the Token Passing Bus Access Method of IEEE 802.4 standard. The LLC is implemented in C language, and MAC in C language and 80186 assembly language. MAC program takes advantage of MC 68824 which is the token bus controller produced by Motorola.

• KIPS Transactions on Computer and Communication Systems
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• v.2 no.4
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• pp.155-162
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• 2013

Routing protocol in ad hoc mobile networking has been an active research area in recent years. However, the environments of ad hoc network tend to have vulnerable points from attacks, because ad hoc mobile network is a kind of wireless network without centralized authentication or fixed network infrastructure such as base stations. Also, existing routing protocols that are effective in a wired network become inapplicable in ad hoc mobile networks. To address these issues, several secure routing protocols have been proposed: SAODV and SRPTES. Even though our protocols are intensified security of networks than existing protocols, they can not deal fluidly with frequent changing of wireless environment. Moreover, demerits in energy efficiency are detected because they concentrated only safety routing. In this paper, we propose an energy efficient secure routing protocol for various ad hoc mobile environment. First of all, we provide that the nodes distribute security information to reliable nodes for secure routing. The nodes constitute tree-structured with around nodes for token escrow, this action will protect invasion of malicious node through hiding security information. Next, we propose multi-path routing based security level for protection from dropping attack of malicious node, then networks will prevent data from unexpected packet loss. As a result, this algorithm enhances packet delivery ratio in network environment which has some malicious nodes, and a life time of entire network is extended through consuming energy evenly.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.12
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• pp.5049-5057
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• 2010

As communication technologies are developed and variety of services to mobile devices are provided, mobile users is rapidly increasing every year. However, mobile services running on wireless network environment are exposed to various security threats, such as illegal tampering, eavesdropping, and disguising identity. Accordingly, the secure mobile communications services to 3GPP were established that the standard for 3GPP-AKA specified authentication and key agreement. But in the standard, sequence number synchronization problem using false base station attack and privacy problem were discovered through related researches. In this paper, we propose an efficient authentication mechanism for enhanced privacy protection in the 3G network. We solve the sequence number synchronization existing 3GPP authentication scheme using timestamp and strengthen a privacy problem using secret token. In addition, the proposed scheme can improve the bandwidth consumption between serving network and home network and the problem of authentication data overhead for the serving network because it uses only one authentication vector.

• Journal of KIISE:Software and Applications
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• v.30 no.7_8
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• pp.792-802
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• 2003

Earlier program plagiarism check systems are performed by using simple text, attribute or token string base on match techniques. They have difficulties in checking program styles which have nothing to do with program syntax such as indentation, spacing and comments. This paper introduces a plagiarism check model which compares syntax-trees for the given programs. By using syntax-trees, this system can overcome the weekness of filtering program styles and have advantage of comparing the structure of programs by syntax and semantic analysis. Our study introduces syntactic tree creation, unparsing and similarity check algorithms about C/C++ program plagiarism checking for internet cyber education and estimate plagiarism pattern.

• The Transactions of the Korea Information Processing Society
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• v.4 no.8
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• pp.2025-2037
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• 1997

The concept-based translation system, which is a part of the Korean spoken language translation system, translates spoken utterances from Korean speech recognizer into one of English, Japanese and Korean in a travel planning task. Our system regulates semantic rather than the syntactic category in order to process the spontaneous speech which tends to be regarded as the one ungrammatical and subject to recognition errors. Utterances are parsed into concept structures, and the generation module produces the sentence of the specified target language. We have developed a token-separator using base-words and an automobile grammar corrector for Korean processing. We have also developed postprocessors for each target language in order to improve the readability of the generation results.

• The KIPS Transactions:PartC
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• v.10C no.6
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• pp.747-754
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• 2003

Thia paper suggests a milti user-authentication system comprises that DNA biometric informatiom, owner's RFID(Radio Frequency Identification) smartcard of hardware token, and PKI digital signqture of software. This system improved items proposed in [1] as follows : this mechanism provides one RFID smartcard instead of two user-authentication smartcard(the biometric registered seal card and the DNA personal ID card), and solbers user information exposure as RFID of low proce when the card is lost. In addition, this can be perfect multi user-autentication system to enable identification even in cases such as identical twins, the DNA collected from the blood of patient who has undergone a medical procedure involving blood replacement and the DNA of the blood donor, mutation in the DNA base of cancer cells and other cells. Therefore, the proposed system is applied to terminal log-on with RFID smart card that stores accurate digital DNA biometric information instead of present biometric user-authentication system with the card is lost, which doesn't expose any personal DNA information. The security of PKI digital signature private key can be improved because secure pseudo random number generator can generate infinite one-time pseudo randon number corresponding to a user ID to keep private key of PKI digital signature securely whenever authenticated users access a system. Un addition, this user-authentication system can be used in credit card, resident card, passport, etc. acceletating the use of biometric RFID smart' card. The security of proposed system is shown by statistical anaysis.