• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.449-454
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• 2006

The advantage of the latest technical development in the field of automation, electronics, telecommunications, informatics, geomatics and global position fixing techniques, achievement in data storing, processing, analysing, transferring and visualisation must be taken into account and applied to the maritime technology in the very near future. We should build new e-Navigation era using those technologies [16]. In the paper the Author proposes to introduce and define two new terms: navitronics - formed by analogy to mechatronics, and nautomatics - created by analogy to geomatics and telematics to be combination of those two disciplines in navigational applications.

• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.197-200
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• 1999

수중작업자 상호간이나 수중작업자와 수상요원간에는 수중작업의 효율 및 안전을 위한 통신 시스템이 필수적이다. 본 연구에서는 국외의 무선수중전화기 개발현황을 살펴보고 무선수중전화기 설계에서 고려해야 할 수중음향통신 환경 전기음향변환기 및 통신방식 등을 분석, 소개하고자 한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.9A
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• pp.712-718
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• 2009

This paper proposes the optimal transmission parameter selection method for an energy efficient Wireless Personal Area Network (WPAN) system which is applicable to the Maritime Telematics targeting for various ship models. Since the transmission parameter selection is an important factor for WPAN system to decide its energy efficiency, we propose an energy consumption model for ship area network (SAN) employing IEEE 802.15.3 based TDMA HR-WPAN model and analyzes the effect of transmission parameter selection on the performance of energy consumption. In particular, the main performance decision parameter of the SAN applying HR-WPAN is path loss, since it is very varied according to the material of shipbuilding such as steel (large ship), FRP (medium size ship) and compound wood (small ship). Thus, we analyzed and demonstrated that the proper transmission parameter selection among transmit power, PHY data rate and fragment size for each ship model guarantee the energy efficiency.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.10A
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• pp.769-775
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• 2009

This paper proposes the optimal transmission parameter selection method for an energy efficient Wireless Personal Area Network (WPAN) system which is applicable to the Maritime Telematics targeting for various ship models. Since the transmission parameter selection is an important factor for WPAN system to decide its energy efficiency, we propose an energy consumption model for ship area network (SAN) employing IEEE 802.15.3 based TDMA HR-WPAN model and analyzes the effect of transmission parameter selection on the performance of energy consumption. In particular, the main performance decision parameter of the SAN applying HR-WPAN is path loss, since it is very varied according to the material of shipbuilding such as steel (large ship), FRP (medium size ship) and compound wood (small ship). Thus, we analyzed and demonstrated that the proper transmission parameter selection among transmit power, PHY data rate and fragment size for each ship model guarantee the energy efficiency.

• Journal of the Korean Institute of Telematics and Electronics
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• v.24 no.1
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• pp.115-122
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• 1987

In this paper, we proposed an improved weakly-coupled power divider(TAP UNIT) for CATV and/or MATV systems, by which the degree of freedom in design and density of coupling interval are signifcantly increased compared with the intrinsic one even though the turn ratios are still of discrete values. On the other hand, the new design theory of a generalized n-way power divider with arbitrary dividing ratios, for CATV and/or MATV systems, which consists of ideal multiwinding transformers and resistors only was presented. Since the circuit elements is not frequency dependent, the proposed power divider is to be of considerably broad bandwidth. Furthermore, the experimental verification has been achieved, and, hence, the validity of the design theory proposed here is confirmed.

• ETRI Journal
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• v.27 no.5
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• pp.639-642
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• 2005

This paper proposes two kinds of complexity-reduced algorithms for a low density parity check (LDPC) decoder. First, sequential decoding using a partial group is proposed. It has the same hardware complexity and requires a fewer number of iterations with little performance loss. The amount of performance loss can be determined by the designer, based on a tradeoff with the desired reduction in complexity. Second, an early detection method for reducing the computational complexity is proposed. Using a confidence criterion, some bit nodes and check node edges are detected early on during decoding. Once the edges are detected, no further iteration is required; thus early detection reduces the computational complexity.

• ETRI Journal
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• v.27 no.2
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• pp.223-226
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• 2005

This paper presents the application of a turbo coding technique combined with a bandwidth efficient method known as trellis-coded modulation. A transformation applied to the incoming I-channel and Q-channel symbols allows the use of an off-the-shelf binary/quadrature phase shift keying (B/QPSK) turbo decoder without any modifications. A conventional turbo decoder then operates on transformed symbols to estimate the coded bits. The uncoded bits are decoded based on the estimated coded bits and locations of the received symbols.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.3
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• pp.113-123
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• 1989

We developed a general algorithm and program to determine nominal value of new optimum geometric parameters of MOSFET when yield satisfying specification of drain current and noise spectral density is maximum. In this paper, the total number of considered devices is 500, and each parameters of geometric parameter was generated randomly within the limits of ${pm}3%$ of nominal value, and the distribution of 500 geometric parameters is gaussian distribution.

• Journal of the Korean Institute of Telematics and Electronics
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• v.23 no.6
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• pp.780-788
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• 1986

1.3\ulcorner GaInAsP BH(Buried Heterostructure) lasers were fabricated on the p-InP substrate. Two step chemical etching processes and melt-back etching technique during 2nd epitaxy were used for BH active layer. BH laser had the threshold current, Ith, of 72mA(23\ulcorner), peak wavelength of 1.2937\ulcorner, nd of 10-20%, and To of 85K. They operated in single mode under pulse condition up to 1.4 Ith. CW(DC) operation was successfully performed at room temperature.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.1
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• pp.15-21
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• 1999

A new design of RF automatic gain control amplifier with low phase shift attenuator is proposed. By using the RF AGC amplifier, the output level of amplifier becomes to be constant. The error is 0.1dB. In addition, for arbitrary RF input power, it is possible to design the gain of amplifier to be fixed. If the constant gain is maintained, it is more reliable to make wanted IMD(Intermodulation Distortion) characteeristic amplifier.