• The KIPS Transactions:PartC
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• v.10C no.5
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• pp.533-540
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• 2003

According to the development of mobile communications, many people have been offered high qualify of the application services using portable terminals. But those works nay have many vulnerabilities and have the limit of excutaions. Because the application services are provided in mobile network and the performance of portable terminals is lower than that of base stations. To improve these problems, in this paper, we propose one-time proxy signature scheme that can reduce the computational ctsost on a user and prevent a proxy agent's dishonesty. The proposed scheme is based on the KBLK scheme [2] which applied the fail-stop signature scheme [1]. It is constructed that a proxy signer can sign only one message with a proxy key and we add anonimity to it for the user's identity protection in mobile communication like a M-commerce.

• Journal of Advanced Navigation Technology
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• v.14 no.3
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• pp.343-350
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• 2010

Wireless Sensor Network is an event-driven system that a large number of micro sensor nodes are collected, giving and Wing information. Congestion can take place easily since a great number of sensor nodes are sensing data and transferring them to sink nodes when an event occurs, comparing to the existing wired network. Current internet transport protocol is TCP/UDP, however, this is not proper for wireless sensor network event-driven ESRT, STCP and CODA are being studied for reliable data transport in the wireless sensor network. Congestion are being detected local buffer and channel loading with these techniques. Broadcasting is mainly used and can avoid congestion when one happens. The way that combining local buffer and channel loading information and detecting congestion is being studied in this paper. When congestion occurs, buffering state is divided into three in order to lessen the broadcasting sending the message on congestion control to the node having frequent channel loading. Thus they have advantage of decreasing network's loading.

• The KIPS Transactions:PartB
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• v.18B no.6
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• pp.355-364
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• 2011

In most applications requiring high-confidential images, reversible watermarking is an effective way to ensure the integrity of images. Many watermarking researches which have been adapted to authenticate contents cannot recover the original image after authentication. However, reversible watermarking inserts the watermark signal into digital contents in such a way that the original contents can be restored without any quality loss while preserving visual quality. To detect malicious tampering, this paper presents a new block-based image authentication algorithm using differential histogram-based reversible watermarking. To generate an authentication code, the DCT-based authentication feature from each image block is extracted and combined with user-specific code. Then, the authentication code is embedded into image itself with reversible watermarking. The image can be authenticated by comparing the extracted code and the newly generated code and restored into the original image. Through experiments using multiple images, we prove that the presented algorithm has achieved over 97% authentication rate with high visual quality and complete reversibility.

• 한국HCI학회:학술대회논문집
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• 2006.02a
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• pp.1379-1386
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• 2006

전자우편이나 문자 메세지를 이용할 때 겪는 불편함 중 하나는 상대방이나 기계에 정서 정보를 전달하기 어렵다는 점이다. 정서 정보를 메시지에 싣기 위해서는 컴퓨터나 디지털 기기가 정서를 인식하거나 사용자가 정서를 입력해야 한다. 기존의 정서 인식 방법은 생리적, 신체적 측정치를 이용하는 것인데, 이 경우 측정을 위한 별도의 장비가 필요하고 현재 자신의 정서 상태와 다른 정서를 표현할 수 없다는 단점이 있다. 특히 소형 모바일 기기를 이용할 때 다른 측정 장치를 사용하는 것은 더욱 어렵다. 이런 문제를 해결하기 위해 모바일 기기를 사용하는 환경에서 사용자가 원하는 정서를 기계에 입력하기 위해 동작을 이용하려는 연구가 진행되었다(Fargerberg, Stahl, & Hook, 2003). 본 연구에서는 Laban Movement Analysis에서 동작을 구성하는 다섯 요소 중 노력(effort)과 모양(shape) 요소를 재구성하여, 방향성 차원, 무게감 차원, 시간감 차원으로 동작을 구분하고 총 20개의 동작을 선정하였다. 또한 한덕웅과 강혜자(2000)가 수집한 834개 정서 어휘를 평정하여 동작을 통해 표현하고 전달되기 쉬운 정서 어휘 50개를 선택하였다. 최종 실험에서 참가자들은 20개의 동작에 대해 50개의 정서 어휘를 평정하고 데이터는 범주형 주성분분석을 이용하여 분석하였다. 분석 결과 Russell(1980)의 이차원 정서 구조 모형에서 각성 수준 차원은 동작의 무게감과 시간감 차원과 관련이 있는 것으로 나타났다. 강하고 빠른 동작일수록 각성 수준이 높은 정서가 나타났다. 또한 동작의 방향성 차원은 정서의 종류와 관련이 있는 것으로 드러났다. 직선 움직임은 높은 각성 수준의 부정적 정서와, 흔듦 움직임은 불안 및 초조와, 원형 움직임은 즐거운 정서와 관련이 있는 것으로 나타났다. 이는 동작을 통하여 정서 정보를 효과적으로 전달할 수 있음을 보여주었고, 동작과 정서를 연관 짓기 위해 방향성 차원과 무게감 차원 그리고 시간감 차원을 고려할 필요가 있음을 시사한다.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.15 no.1
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• pp.95-101
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• 2016

Vehicular communications is system which can be applied for transmission of various safety messages or Intelligent Transportation Systems(ITS) applications by combining vehicle/road technology with Information and Communication Technology(ICT). In recent years, a variety of ITS services are available such as driving information, road conditions, V2X messages as well as navigation and traffic jams notification. In general, vehicular communications can be used for vehicle-to-vehicle and vehicle-to-infrastructure communication by adopting IEEE802.11p/1609 standard which is commonly known as wireless access in vehicular environments. In this paper, WAVE communication standard based on the IEEE802.11p is explained and signal characteristics in WAVE communication is introduced. Also, The H/W and S/W characteristics in Road Side Station and On Board Equipment for the Vehicle to Everything communication are analyzed. Received Signal Strength which is power of receiving signal of communication equipment is measured in test road to estimate the real WAVE communication's performance. It is shown that the implemented WAVE communication technology is satisfactory to provide ITS services.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.2B
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• pp.184-194
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• 2011

Security is critically important for smart grid networks that are usually used for the electric power network and IT environments that are opened to attacks, such as, eavesdropping, replay attacks of abnormal messages, forgery of the messages to name a few. ZigBee has emerged as a strong contender for smart grid networks. ZigBee is used for low data rate and low power wireless network applications. To deploy smart grid networks, the collected information requires protection from an adversary over the network in many cases. The security mechanism should be provided for collecting the information over the network. However, the ZigBee protocol has some security weaknesses. In this paper, these weaknesses are discussed and a method to improve security aspect of the ZigBee protocol is presented along with a comparison of the message complexity of the proposed security protocol with that of the current ZigBee protocol.

• The Journal of Society for e-Business Studies
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• v.11 no.2
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• pp.13-30
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• 2006

Web services are independent on a platform and are suitable in the Ubiquitous environment which an interaction for each device. Ubiquitous web services can use various applied service in any network neighborhood or terminal. Main characteristic of Ubiquitous is context-awareness. Therefore, Ubiquitous web services must include context-aware control process and protect user privacy because context-aware environment collects privacy data. But current web services standard is not specially designed in respect of context-communication. Therefore, the framework which can add flexibility in transmission of context is required. Our Framework can give extension for context and can communicate flexibly Context information for every session. Therefore, Our Framework can solve overhead problem of context in SOAP message and protect user's privacy according to user preference.

• The Transactions of the Korea Information Processing Society
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• v.3 no.7
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• pp.1803-1811
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• 1996

In a distributed multiagent framework, the capabilities of each agent are known to other agents. Namely, each agent in a multiagent society is aware of what agents are available in the whole society, which is able to solve a query, and how to contact them. This characteristic leads to the simplicity in controling both local and remote interactions among agents by using a fixed form for communication packes. This paper presents methods for controlling interactions among agents in this distributed multiagent frame-work. Agent interactions are described within the platform of MASCOT that is a tightly coupled multiagent system developed for the role of a computer secretary. A frame-like form of a commumication packet is defined, and protocols for message exchanges are presented. Also, ascenarios given to demonstrate how the communication mechanism controls agent intercations in MASCOT.

• The Journal of the Acoustical Society of Korea
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• v.19 no.2
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• pp.101-105
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• 2000

A telegram has been used to transmit the emergency news or celebration message. So, it has been very important media in our life. Although the telegram processing is more and more convenient, on the other hand, the telegram service contains only text message. The voice telegram is that delivering user's voice with text message. So, the voice telegram can be delivered sender's emotions and feelings. However, since voice information contains lots of data, large memory size and high cost processor are needed to deliver itself. In this paper, we proposed a new speech waveform coding method that has low complexity and low cost implementation for the voice telegram system. First, we fixed one basic speech waveform per pitch period and measured the waveform similarity between basic and neighbor speech waveform. Second, if the similarity satisfied threshold values, we compress the neighbor speech waveform with pitch and magnitude value per pitch period and if not, we save speech waveform. When the compression is about 45%, we obtained about 4 point in MOS.

• Journal of KIISE:Information Networking
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• v.35 no.3
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• pp.183-191
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• 2008

In this paper, we propose Stream Control Transmission Protocol(SCTP) proxy which supports making an SCTP connection from a Corresponding Node(CN) to a Mobile Node(MN). Recently, mobility support in transport layer is proposed, which provides mobility in end-to-end way using the extension of SCTP. Mobile SCTP can provide handover to all applications that use SCTP as a transport protocol. However, current SCTP does not include independent location management service and can not make connection from a CN to a MN without assistance of other mobile protocols. To solve this problem, Proposed SCTP proxy interoperates with generic location management service and performs an address transformation to forward connection set up messages to the MN. Using the proposed proxy, SCTP can provide a complete mobility support including a connection setup to the MN and maintaining an existing connection.