• KSCI Review
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• v.14 no.2
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• pp.123-127
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• 2006

In this paper, we designed and implemented home gateway system for remote control of home appliances and devices using cellular phone. The system communicate home devices through Zigbee protocol and home server based on Linux operating system communicate cellular phone through external networks. We expect that the system apply various fields as home automations, home network, smart offices, and ubiquious environments.

• Journal of the Korea Society of Computer and Information
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• v.19 no.4
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• pp.71-79
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• 2014

This paper investigates wideband dual-polarized microstrip antenna with H-shaped coupling slot. These types of antennas are used to prevent deterioration of transmission quality caused by terminal interference or multipath fading, which usually occur when many terminals are used in limited space such as hot-spot zones. The experimental results show that the impedance bandwidth ($SWR{\leq}2$) of 33.98% and the peak gain of 8.58 dBi (at 2.11 GHz) were obtained by the frequency band under 2.7 GHz. The proposed antenna is designed originally for multiple service bands with simple structure and easily be mass-produced for various commercial applications.

• Proceedings of the Korean Society of Computer Information Conference
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• 2013.07a
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• pp.311-313
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• 2013

본 논문에서는 W-PAN 환경에서 IP공유기를 표준설계하고 구현하며 효율적인 실시간 사용자 웹기반 인증 기법을 연구하였다. 또한 W-PAN Device & Service Application 인증과 접근, 권한제어를 위한 인증 Client 모듈과 Server 모듈, Supplicant를 개발하고 제안하였다. 이를 통해 IP 공유기 기반 환경에서의 W-PAN 환경에서 인증 제어 솔루션에 대한 개발로 생산되는 단말기의 서비스 품질을 향상시키고 무선 접속 기술을 표준화 할 수 있다. 또한 유해한 트래픽을 검색하고 보호하는 안정적인 시스템 관리가 가능해졌다. W-PAN Device와 Service Application 인증, 접근 및 권한 제어를 위한 인증 시스템의 플랫폼 구축으로 향후 관련 기술의 통합과 융합 기술을 적용할 수 있는 능력을 확보하였다.

• Journal of the Korea Society of Computer and Information
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• v.9 no.2
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• pp.41-48
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• 2004

Access control protocol have verified security of external mobile terminal that access to inner information sever at Ubiquitous ages. In this paper, I would design for If Access Control Protocol of considering operation time when make cipher digital signature. Public key are used Individual identification number that issued from certify communication company, and cipher algorithm are used ECDSA definition factor for generation and verification of digital signature and it used Elliptic Curve with over 160 bit Key. Also, Access control operate on If level that designed IPv6 frame architecture. I would conclude that IP Access Control Protocol have verified security and improved performance in operation time more 4 times than before protocols when through the communication of use cipher digital signature for authentication and verification.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.5
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• pp.165-172
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• 2016

This paper presents an implementation of a live audio streaming system using the Raspberry Pi 3 embedded computer. This system is a live streaming system not file-based streaming. This is a push streaming system which converts the incoming analog audio signal to digital samples and broadcasts them to multiple connected users concurrently. Since the server software is developed in Java language, it can be installed on any other embedded computers without any modification. We concluded that ESCatcher can service live streaming about 60 users concurrently through calculations and experiments, And also we achieved the delay time of a little bit more than 40ms between arrival of audio source and play on the android device.

• Journal of the Korea Society of Computer and Information
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• v.10 no.2 s.34
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• pp.133-141
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• 2005

We need to study on simulation method of user's mobility Patterns for the performance analysis of the location management in wireless mobile networks. For this purpose ,this paper presents a user mobility model of wireless mobile networks with regular Patterns Sometimes mobile users randomly move , but they show the movement characteristics that regularly change their locations in some patterns in given time slots. So, we suggest the mobility model that can describe user's time related movement patterns. This model consists of some elements-positions, transitions , transition Probabilities which are variable, and some geographical paths for each transitions. We describe the simulation method for users' mobilities with random movements and regular movements , too. The simulation results by the model show that the suggested model can generate movement scenarios having regular patterns related with location and time.

• Journal of the Korea Society of Computer and Information
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• v.10 no.2 s.34
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• pp.159-167
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• 2005

Through the increment of group oriented application services, the multicast communication in wire/wireless network has become a widely discussed researching topic. However solution for security, efnciency and scaleability of a multicast communications are not enough to be satisfactory. Tn this paper, we Propose a new secure, efficient and scalable multicasting protocols to provide a integrated multicast service. Our protocol is an authenticated key establishment protocol which has been designed specifically for use with low powered computationally weak equipment such as Cellular phone and PDA(Personal Digital Assistant).

• Journal of the Korea Computer Industry Society
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• v.2 no.9
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• pp.1219-1224
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• 2001

There can exist unidirectional links due to asymmetric property of mobile terminals or current wireless environments on practical mobile ad hoc networks. However, at present, the existing mobile ad hoc routing protocols are implemented to support only bidirectional links. Thus, in this paper, we extend the existing dynamic source routing protocol in order to implement a new routing protocol, which is fit to mobile ad hoc networks containing unidirectional links. For performance evaluation, we use combinations of mobility scenario files and connection pattern files from Carnegimelon Univ. We consider received data rate and average route discovery time as evaluation items, which are compared and evaluated for three suggested route discovery methods.

• Proceedings of the Korean Information Science Society Conference
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• 2005.11b
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• pp.616-618
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• 2005

본 논문은 적외선 리모트 컨트롤러로 제어가 가능한 가정용 소형 로봇인 $Robosapien^{TM}$을 홈 네트워크 제어를 위한 홈 서버를 통해 직접 제어할 수 있는 제어 소프트웨어를 개발하였다. 또한 $Robosapien^{TM}$의 연속적인 동작을 쉽게 프로그래밍하고 실행시킬 수 인터프리터 (interpreter)의 세부 구현내용을 기술하였다. 본 구현은 컴퓨터 프로그래밍의 개념 정립이 부족한 일반 사용자나 컴퓨터 프로그밍에 관심이 많은 학생들이 쉽게 프로그래밍 할 수 있는 비주얼 프로그래밍 도구를 개발하였다. 특히 구현 시 필요한 구성 요소 및 기능을 설계하고 사용자의 편의성을 고려한 편리한 GUI(Graphical User Interface)의 구현에 중점을 두었다. 본 비주얼 프로그래밍 도구는 가정의 데스크톱 PC뿐만 아니라, 실외에서 PDA와 같은 소형 이동단말기를 이용하여 원격으로 가정의 홈 서버에 접속하여 $Robosapien^{TM}$의 동작을 실시간으로 제어할 수 있으며 가정의 웹 카메라를 통하여 $Robosapien^{TM}$이 정확하게 동작하고 있는지를 원격으로 확인할 수 있다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.05a
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• pp.243-248
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• 2002

The development of digital technologies and the appearance of computers have brought inevitable changes on the conventional printing publishing system and forms of books. An electronic book has marked its birth, sending out the contents of a book in digital and not using paper books but tile exclusive terminal. As far as systems are concerned, reading and publishing are going the separate ways is kind of impediments should be overcome by introducing the on-line order and sales service and constituting a network interworking service which delivers digital book contents on-line. This paper concerned the book publishing mode which would help to overcome the impediments. The last system is the one with broadcasting and communication as well as computers and the Internet mixed in a very complex way.