• Journal of Digital Convergence
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• v.10 no.11
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• pp.351-358
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• 2012

This study is aimed at suggesting optical communication equipment that can deliver high quality video information in high speed, to efficiently handle the flood and water pollution in the river basin. This system is cheaper than existing equipment, and can monitor optical Internet as well as the condition of equipment. Generally, the communication equipment to prevent flood is installed in an unmanned control box and operated by the flood control office situated at the fiver mouth in a long distance section. Therefore, it is hard to promptly cope with communication interruptions, which occur by the cutting or aging of the optical cable. Under the circumstances, this study suggested an efficient system that can deliver high quality video information in high speed (Optical Transmission Convert System) by using optical fiber. The system also solves problems by making use of automatic protection switching (APS) when an accident happens. Its real-time monitoring function gives notice of the problem-occurring points. The system is expected to be widely used in various areas such as intelligent traffic systems.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.5
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• pp.517-524
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• 2004

In this paper, we investigated the compensation characteristics of distorted NRZ format and RZ format signal dependence on dispersion variation of each transmission section in 8-channel WDM system. The WDM system have two transmission sections of unequal length with respect to optical phase conjugator(OPC) position. We select highly-nonlinear dispersion shifted fiber(HNL-DSF) as a nonlinear medium of OPC in order to convert wideband signal waves to conjugated waves. First, we confirmed that RZ is better than NRZ as a modulation format for maintenance or stable performance, when total dispersion or both sections in WDM system is different each other. Also, we confirmed that total dispersion of the short length section must be smaller than that of the long length section in order to excellently compensate for NRZ format signal.

• Korean Journal of Optics and Photonics
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• v.5 no.1
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• pp.25-30
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• 1994

We derive a set of formuale which show one-to-one correspondence between the the unitary Jones matrices of transparent anisotropic media and the rotational transformations on the Poincare sphere. By using the formuale one can determine the vectorial representation of the rotational transformation on the Poincare sphere which specifies the direction of the axis and the angle of the rotation in terms of the three parameters specific to the corresponding unitary Jones matrix, and conversely the the three parameters of the uniatry Jones matrix in terms of the vectorial representation of the corresponding rotational transformation on the Poincare sphere. To understand the polarization transmission characteristics of an optical system consisting of transparent linear anisotropic media, start with the Jones calculus to get the unitary Jones matrix for the whole system and then convert it to a rotational transformation on the Poincare sphere, from which we can intuitively understand the effect of the optical system on the polarization state of the light passing through the system.

• Journal of the Korean Solar Energy Society
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• v.31 no.2
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• pp.82-88
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• 2011

The artificial increase in the solar intensity incident on solar cells using lenses or mirrors can allow solar cells to generate equivalent power with a lower cost. There are two types of concentration optics for solar energy conversion. One is to use mirrors, and the other is to use Fresnel lenses. The gains that can be achieved with a Fresnel lens or a parabolic mirror are compared. The result showed the gains are comparable and the two configurations were developed competitively. In application areas of Fresnel lenses as solar concentrators, several variations of design were devised and tested. Some PV systems still use commercially available flat Fresnel lenses as concentrators. A convex linear Fresnel lens to improve the concentration ratio and the efficiency is devised and flat linear Fresnel lens in thermal energy collection is utilized. In this study, we designed and optimized flat Fresnel lens and the 'light pipe' to develop 500X concentrated solar PV system. In the process, we compare the transmission efficiencies according to groove types. We performed rigorous ray tracing simulation of the flat Fresnel lenses. The computer aided simulation showed the 'grooves in case' has the better efficiency than that of 'grooves out case'. Based on the ray-trace results we designed and manufactured sample Fresnel lenses. The optical performance were measured and compared with ray-trace results. Finally, the optical efficiency was measured to be above 75%. All the design and manufacturing were performed based on that InGaP/InGaAs/Ge triple junction solar cell is used to convert the photon energy to electrical power. Field test will be made and analyzed in the near future.

• Journal of the Korea Institute of Military Science and Technology
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• v.24 no.6
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• pp.645-654
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• 2021

In this paper, we proposed a protocol to convert 2W telephone analog signals to Ethernet data in a private PSTN 2W tactical voice system. There are several kinds of operational problems in the tactical telephone network where 2W telephone copper lines are installed hundreds of meters away from the PBX in a headquarter site. The reason is that it is difficult to install and maintain the 2W telephone copper cable in severe operational fields and to meet safety and stability operational requirements of the telephone line under lighting and electromagnetic environments. In order to solve these challenging demands, we proposed an efficient method that the 2W analog interface signals between a private PBX system and a 2W telephone is converted to Ethernet messages using the optical Ethernet data communication network already deployed in the tactical weapon system. Thus, it is not necessary to install an additional optic cable for the ethernet telephone line and to maintain the private PSTN 2W telephone network. Also it provides safe and secure telecommunication operation under lightning and electromagnetic environments. This paper presents the conversion protocol from 2W telephone signals over Ethernet interface between PBX systems and 2W telephones, the mutual exchange protocol of ethernet messages between two converters, and the rule to process analog signal interface. Finally, we demonstrate that the proposed technique can provide a feasible solution in the tactical weapon system by analyzing its performance and experimental results such as the bandwidth of 2W telephone ethernet network and the transmission latency of voice signal, and the stability of optic ethernet voice network along with the ethernet data network.