• The Transactions of the Korea Information Processing Society
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• v.4 no.1
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• pp.195-208
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• 1997

ISDN is network which has been developed to integrate and transfer some information(data, video, voice). In the ISDN, security problem that threat and intrusion about important information resource increase because every information is transferred in the form of digital and access of network has patiency. In this paper, for protect important information resource, studied that apply application method and encryption system to ISDN, and system structure, ITU-T Q.931 protocol were analyzed, and proposable encryption key distribution protocol, call control with hybrid encryption system for user information privacy to provide security service.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.218-221
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• 2003

In this report, we test the features that the outside environment of subscriber lines have an effects on ADSL's electrical transmission performance with a suspected cases of line. I observed an influence of AM broadcasting jamming, and also analysis of an incoming lines of various kinds, a line distance, a connection way, Bridge Tap influencing ADSL's electrical transmis-sion performance. To have a maximum effect of Adsl electrical transmission, I came to a conclusion that we have to make use of the older copper wire cable line to fit the situation at the present and we must change it into the excellent optical fiber cable one by one.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.4
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• pp.371-378
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• 1992

In this paper we report the fabrication of a planar optical wavehuide lens on a Y-cut LiNbO3 substrate by Ti_indiffusion and Ti-indiffused proton-exchange(TIPE). LiNbo3 planar waveguides are fabricated and refractive indices of the waveguides are fabricated and refractive indices of the waveguides are measured. Based on the measured indices, palanr waveguide lenses are designed and fabricated. The measured focal point and spot size of the fabricated lens are in good agreement with those of the designed lens.

• Korean Journal of Optics and Photonics
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• v.15 no.1
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• pp.22-27
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• 2004

In this paper, we designed a mode size converter to reduce coupling loss between optical waveguide and single mode fiber. The proposed mode converter is composed of periodically segmented tapered waveguide to achieve small size and easy fabrication. For the optimally designed mode size converter at 1550nm, the taper length is 500(equation omitted), the segmentation period 5ß:, the waveguide width of fiber contact section 1.3ß:, and duty cycle 0.95. The coupling loss of the optimized mode size converter is 0.33㏈/point, which is 1.27㏈/point lower than that without the mode size converter.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.4
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• pp.27-32
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• 2014

Two-dimensional hybrid codewords are generated by using each row of identity matrix for spatial encoding and nonideal symmetric balance incomplete block design(BIBD) code for spectral encoding. This spatial/spectral optical code-division multiple-access (OCDMA) network uses single-balanced detectors to abstract the desired information bits and to eliminate the multiple-access interference(MAI). Analytical results show that the number of simultaneous users increases significantly by using the proposed hybrid codes.

• 한국정보통신설비학회:학술대회논문집
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• 2009.08a
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• pp.309-313
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• 2009

In this paper, the network performance of a turbo coded optical code division multiple access (CDMA) system with cross-layer, which is between physical and network layers, concept is analyzed and simulated. We consider physical and MAC layers in a cross-layer concept. An intensity-modulated/direct-detection (IM/DD) optical system employing pulse position modulation (PPM) for satellite broadcasting communications is considered. In order to increase the system performance, turbo codes composed of parallel concatenated convolutional codes (PCCCs) is utilized. The network performance is evaluated in terms of bit error probability (BEP). From the simulation results, it is demonstrated that turbo coding offers considerable coding gain with reasonable encoding and decoding complexity. Also, it is confirmed that the performance of such an optical CDMA network can be substantially improved by increasing the interleaver length and the number of iterations in the decoding process. The results of this paper can be applied to implement the satellite broadcasting communications.

• JOURNAL OF ELECTRICAL WORLD
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• s.306
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• pp.73-80
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• 2002

인터넷으로 대표되는 네트워크와 휴대전화의 결합으로 문자 그대로 지구규모의 디지털사회가 출연하게 되었고 사회제도와 공공의 정보기반도 그것을 반영한 형태로 변화하고 있다. 차후 디지털사회를 얼마나 안전한 것으로 만들어 가는가는 국가$\cdot$사회의 기반으로서 그 존속에 관계되는 중대한 문제이며, 기업 비즈니스에서는 사활(死活)을 건 비즈니스 문제가 되었다. 이들을 지탱하는 정보기반의 핵이 바로 암호를 중심으로 하는 정보시큐리티이다. 여기서는 현대 사회에서는 왜 암호$\cdot$정보시큐리티가 필요한가, 그 역할과 의미는 무엇인가, 어떠한 응용분야, 과제가 있는가를 전망해본다. 또한 암호란 무엇인가, 그 안전성의 의미란 무엇인가, 컴퓨터나 통신의 디지털기술과는 어떤 관련이 있는가를 역사적 배경과 최근의 동향을 바탕으로 언급하고, 현대암호의 성립, 정보시큐리티의 적용형태, 미쓰비시(삼릉)전기의 기술적 활동에 대하여 언급한다. 앞으로 전개되는 디지털 사회의 동향으로는 두 가지의 특징을 들 수 있다. 우선 휴대전화의 세계적 보급, 인터넷접속기능 장비의 발달로 현재 인터넷 유저(사용자)의 규모를 훨씬 능가하는 음성교신이 가능한 모바일인터넷의 출현이 예상된다. 모바일인터넷이 잠재적으로 갖는 안전상의 취약성을 극복하기 위해서는 암호$\cdot$정보시큐리티 기술은 보다 고도의 것이 요구된다. 또한 장래의 양자(量子)컴퓨터이 출현 등 분자레벨로 육박해 오고 있는 반도체$\cdot$광소자$\cdot$통신기술에 앞서 현재의 디지털암호에 의한 시큐리티기반의 안전성에 대한 한계가 거론되고 있다. 디지털사회의 안전성을 확보하기 위해서는 장래를 내다본 기술의 추구가 요청되고 있으며 그 대표적인 것으로 양자역학의 원리, 광기술, 디지털기술을 통합한 양자암호가 있다. 미쓰시비전기는 2000년 9월에 일본 최초로 양자암호의 실증실험에 성공하여 조기 실현화를 지향하고 있다.

• Proceedings of the KIPE Conference
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• 2003.07b
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• pp.949-952
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• 2003

인터넷으로 표현되는 디지털 세상은 빠른 속도로 변하는 삶 전체에 영향을 미치는데, 특히 산업체에서의 업무와 일하는 방식을 바꾼다. 인터넷과 웹 접속 기술은 현재의 업무 과정을 개선하고, 전통적인 제조 기업의 생산성과 관리 효율을 극대화한다 본 논문에서는 이러한 발전 설비의 안정성과 원거리 모니터링의 신뢰성과 PV시스템의 제어에 관한 것이다 그리고 PV시스템의 센서 모니터링 데이터와 간접적인 제어를 설계하였다. 전통적인 모니터링 시스템은 특수한 하드웨어나 소프트웨어에 의존한다 모니터링 시스템의 기본적인 목표는 사용자가 휴대용 단말기를 통해 모니터링과 제어를 할 수 있게 하는 것이다. Labview GUI를 이용하여 설계한 모니터링 시스템은 윈도우 2000을 운영체제로 한 IBM PC를 사용하였고, TCP/IP 프로토콜에 기본을 두었다. 이러한 모니터링 시스템의 이점은 사원의 지출(급여)를 줄이고 지구 어느 곳에서든 발전 시스템을 인공위성을 통하여 모티터링과 제어를 할 수 있다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.1B
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• pp.31-41
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• 2000

It has been known that the optical code division multiple access (OCDMA) is a prominent future technology to support many simultaneous users and to increase transmission capacity of optical fiber. In this paper, we proposed the new construction of 2 dimensional code, which can be used as a codeword in temporal/wavelength OCDMA networks. New code family is obtained by extending the concept of Hamming correlation. All optical encoder and decoder for newly proposed code were also developed. In considering bit error ratio, we verified that new coding scheme outperforms conventional coding scheme by simulation. This system is applicable to asynchronous fast local area network, which needs a high security level and a flexible network configuration.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.6
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• pp.1562-1574
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• 1998

We, in this paper, have implemented T1, E1 and fractional E1 HDSL(High-bit-rate digital subscriber line) function over an ATM switching system. The maxi$\mu$ loop lengths for subscriber service and cell loss rates to meet the bit error rate of 10$^{-7}$ at transmission of 2B1Q HDSL data E1 rate over existing telephone copper wires in the presence of the significant impairments such as NEXT(Nearned crosstalk), impulse noise, power line noise and longitudinal over the CSAs environment consisting of 26 gauge and 25 gauge unloaded copper telephone lines has assessed. HDSL will intially be used to serve private-DS1, ISDN-BRA, and DLC feeders, later DS1 extension from optic fiber cable. We also present market provision for the HDSL.