• Journal of the Institute of Electronics Engineers of Korea SD
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• v.48 no.12
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• pp.66-72
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• 2011

In Japan, the specification for digital terrestrial television broadcasting systems has been approved for employing a transmission scheme for ISDB-T, which can accommodate HDTV service and portable mobile reception by adapting segmentation of frequency. In this paper, we have developed 3.5 inch mobile TV according to One-Seg system and presented the results of our development. In addition, we introduce two diversity schemes to compensate the defect that signal is interrupted when the portable TV is moving fast. In order to achieve a reliable communication in One-Seg system, we introduce STD(space time diversity) which uses more than 2 antennas at TX and cooperative reception diversity which utilizes signal-exchanging between different mobile terminals. And, its performance enhancements to reception reliability of previous system are evaluated by computer simulations.

• Aerospace Engineering and Technology
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• v.5 no.2
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• pp.143-148
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• 2006

This article summarizes the results of sea transportation load measurements, which will be used as the reference to the sea transportation environment condition for the launch vehicle of KSLV-I. KSLV-I will be transported by Sea from Pusan to the NARO space center in Gohung, Chunnam province. Since the vibration load condition during sea transportation is considered as one of the important design parameters of KSLV-I and its transportation means, it is necessary to directly measure the environmental condition of sea transportation loads prior to establish the sea transportation plan in detail. This material includes the measured data of 3-axis linear accelerations and 3-axis angular rates on the board of a barge-ship, which is towed by a tug boat during shipping operation. This barge-ship is same class with one which will actually carry KSLV-I. The results show that the measured load condition during sea transportation is not severer than the reference data of MIL-STD-810F and Zenit-3SL launch system.

• Journal of Navigation and Port Research
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• v.27 no.2
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• pp.223-231
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• 2003

In this paper, we present a scheme for developing a simulator which verify the AGV system operation in automated container terminal. First of all, we propose a guide path in automated terminal considering AGV productivity and present a traffic control scheme in a such guide path. Generally, the AGV system can be controlled by zone control scheme, but there are no flexibility and use simple operation. In this paper, we propose and use grid based control scheme to improve the flexibility of the AGV movement. Lastly, we construct the simulation environment which can do similar to that of real task and ease the modification and improvement of the control logics.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.11
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• pp.1088-1093
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• 2014

The structure of the fire control system(FCS) of a light armed helicopter and effective logistics support was taken into account in the proposed common weapon interface module(CWIM) for a distributed FCS. The pros and cons of a distributed FCS and a centralized FCS were analyzed, then a CWIM which can be applied to the weapon interface module of a distributed FCS was designed and fabricated. Integration tests between the proposed CWIM and a weapon simulator were conducted to ascertain whether or not the proposed CWIM could be applicable to a distributed FCS. We expect that the CWIM design approach method secured through this study will be helpful in mitigating cable work of the FCS which will be applied to a Light Armed Helicopter and controlling various weapons.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.11C
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• pp.1541-1550
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• 2004

In this paper, we propose an advanced hardware architecture for fast multi-resolution motion estimation of the video coding standard MPEG-1,2 and MPEG-4 AVC. We describe the algorithm and derive hardware architecture emphasizing the importance of area for low cost and fast operation by using the shared memory, the special ram architecture, the motion vector for 4 pixel x 4 pixel, the spiral search and so on. The proposed architecture has been verified by ARM-interfaced emulation board using Excalibur Altera FPGA and also by ASIC synthesis using Samsung 0.18 m CMOS cell library. The ASIC synthesis result shows that the proposed hardware can operate at 140 MHz, processing more than 1,100 QCIF video frames or 70 4CIF video frames per second. The hardware is going to be used as a core module when implementing a complete MPEG-4 AVC video encoder ASIC for real-time multimedia application.

• Transactions on Electrical and Electronic Materials
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• v.5 no.1
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• pp.1-6
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• 2004

Zinc sulfide is a semiconductor with wide band gap and high refractive index and hence promising material to be used as ARC on commercial silicon solar cells. Uniform deposition of zinc sulfide (ZnS) by using chemical bath deposition (CBD) method over a large area of silicon surface is an emerging field of research because ZnS film can be used as a low cost antireflection coating (ARC). The main problem of the CBD bath process is the huge amount of precipitation that occurs during heterogeneous reaction leading to hamper the rate of deposition as well as uniformity and chemical stoichiometry of deposited film. Molar concentration of thiorea plays an important role in varying the percentage of reflectance and refractive index of as-deposited CBD ZnS film. Desirable rate of film deposition (19.6 ${\AA}$ / min), film uniformity (Std. dev. < 1.8), high value of refractive index (2.35), low reflectance (0.655) have been achieved with proper optimization of ZnS bath. Decrease in refractive index of CBD ZnS film due to high temperature treatment in air ambiance has been pointed out in this paper. Solar cells of conversion efficiency 13.8 ％ have been successfully achieved with a large area (103 mm ${\times}$ 103 mm) mono-crystalline silicon wafers by using CBD ZnS antireflection coating in this modified approach.

• The KIPS Transactions:PartA
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• v.18A no.5
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• pp.181-192
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• 2011

Information superiority is an essential factor in modern warfare and it can be archived by efficient information exchange between systems. Various computing systems are installed on the today's navy vessels. However, it is hard to improve interoperability and efficiency of information exchange since the configurations of installed systems are varying. The military standard and commercial standard are mix-used between systems. In this paper, we propose an information exchange architecture based on Pub/Sub model as a communication middleware to improve interoperability as well as enhancing scalability. We also propose a novel tree matching algorithm to improve a performance of PubSub broker. In the proposed algorithm, each tree nodes have information about predicates of subscription that can reduce event matching time. The performance evaluation results show our proposed algorithm reduces time for matching predicates compare with other algorithms.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.252-252
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• 2010

적외선 센서는 빛의 유무에 관계없이 주 야간 전방의 물체에서 발산하는 미약한 적외선(열선)을 감지하여 영상으로 재현하는 열상시스템은 자동차 야간 운전자 보조용 나이트 비젼, 핵심 시설의 감시 관리, 군수 등의 분야에 적용되어지고 있는 최첨단, 고부가가치를 지니고 있는 기술이다. 양자형은 센서 특성은 좋으나 냉각기(작동온도: $-196^{\circ}C$) 및 고진공 패키지인 dewar를 사용하는 반면에, 열형은 대부분 상온에서 동작되는 온도안정화를 위한 전자냉각모듈만을 구비하면 되므로 저가형으로 제작이 가능한 비냉각형 적외선 센서이다. 본 연구에서는 적외선 센서용 진공패키지 조립공정 및 패키지된 센서의 측정기술을 개발하였다. 금속 메탈패키지를 제작하였으며, 금속 진공패키지는 소자냉각용 TE Cooler와 장수명 진공유지를 위한 getter, 그리고 센서칩, 온도센서를. 장착하여 칩을 조립하였다. Cap ass'y와 base envelop의 솔더링 공정을 수행하였으며, 진공패키지의 진공유지를 위해 TMP를 이용하여 진공을 유지하고, 약 5일동안 패키지 bake-out을 수행하였다. 진공압력은 $10^{-7}\;torr$ 이하를 유지하였으며, getter를 활성화시키고, pinch-off 공정으로 조립 ass'y를 완성하였다. 진공 패키지의 기밀성은 He leak tester를 이용하여 측정하였으며, ${\sim}10^{-9}\;std.cm^3/sec$로 기밀성을 유지하였다. TE cooler를 작동한 온도안정성은 0.05 K 이하였다. 볼로미터 센서의 반응도는 $10^2\;V/W$ 이상을 나타내었으며, 탐지도는 $2{\times}10^8cm-Hz^{1/2}/W$를 나타내었다. 본 연구를 통하여 얻어진 결과는 향후 2차원 열영상용 어레이 검출기 및 웨이퍼수준의 패키징 공정에 유용하게 응용될 것으로 판단된다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.8
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• pp.3800-3805
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• 2012

Infrared(IR) reflective black cool pigment and paint which is used for interior/exterior materials(IR reflectance >30%) to prevent heat island effect and to increase energy efficiency were studied. Cool pigment was synthesized using mixture of $Fe_2O_3$ and $Cr_2O_3$ with calcination from 900 to $1,200^{\circ}C$. Cool paint was prepared by formulation of cool pigment, acrylic resins, and other additives. Results showed that optimum color fixation of pigment obtained by mole ratio of Fe to Cr was 0.9 with calcination temperature at $1,000^{\circ}C$. The cool paint formulated by 20% pigment and 1.5% dispersive additive with $125{\mu}m$ thickness of coated layer showed optimum IR reflectance. Temperature difference on surface between cool paint and ordinary paint(STD) was $36.5^{\circ}C$ and IR reflectance(TSR) was 39.3% at wavelength from 700 to 2,500nm. And color change was not detected during 500hrs weathering test.

• Journal of Advanced Navigation Technology
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• v.23 no.5
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• pp.444-451
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• 2019

In this paper, we introduce the design consideration of the EMI and lightning induced transient protection circuit for RS-170a video signal on the avionics equipment. Avionics equipment is subject to the risk of malfunction or physical damage due to indirect lightning effect from lightning strike or electromagnetic interference from external environment. So in order to protect the avionics equipment from these effects, we should analyze the effect of electromagnetic interference and lightning strike on aircraft and apply protection design for each avionics device, but protection circuit may cause signal distortion if signal level is low and frequency is high. In this paper, we introduce common protection design for EMI and indirect lightning effect, and consideration for minimize signal distortion caused by protection circuit for RS-170a. In addition, we show some example of improvements to the actual equipment design using consideration discussed in this paper.