• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.2C
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• pp.139-147
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• 2010

A novel turbo coded modulation scheme, called turbo-APPM, for deep space optical communications is constructed. The constructed turbo-APPM is a serial concatenations of turbo codes, an accumulator and a pulse position modulation (PPM), where turbo codes act as an outer code while the accumulator and the PPM act together as an inner code. The generator polynomial and the puncturing rule for generating turbo codes are chosen to show the low bit error rate. At the receiver, the joint decoding is performed by exchanging soft information iteratively between the inner decoder and the outer decoder. In the outer decoder, a local iterative decoding for turbo codes is conducted before transferring soft information to the inner decoder. Poisson distribution is used to model the deep space optical channel. It is shown by simulations that the constructed turbo-APPM provides coding gains over all previously proposed schemes such as LDPC-APPM, RS-PPM and SCPPM.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.45 no.4
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• pp.35-41
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• 2008

When memory devices are exposed to a space environment. they suffer various effects such as SEU(Single Event Upset). For these reasons, memory systems for space applications are generally equipped with error detection and correction(EDAC) logics against SEUs. In this paper, the error detection and correction strategy in the Mass Memory Unit(MMU) of the STSAT-3 is discussed. The probability equation of un-recoverable SEUs in the mass memory system is derived when the whole memory is encoded and decoded by the RS(10,8) Reed-Solomon code. Also the probability value is analyzed for various occurrence rates of SEUs which the STSAT-3 possibly suffers. The analyzed results can be used to determine the period of scrubbing the whole memory, which is one of the important parameters in the design of the MMU.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1255-1261
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• 2010

An operating information and fault recode of train is very important information for safety driving and maintenance. And these information is increased and need high speed as the number of trains is increased. Wireless LAN or CDMA network is efficient to report more complicated and various information from vehicle to server in control center. Existing wireless transmission system has weakness due to transmission system is separated with TDCS and standalone. At first, standalone system needs space to be installed and cost is increased. And data transmission capacity and speed is limited by complicated structure that transmission system receive data thru serial communication like RS232 and then data transmission system send data to server in control center. This article is study to develop embedded & wireless fault code transmission device to be installed in TDCS to overcome weakness of space and to have more cost effective and simple structure. It is adapted 802.11b/g WiFi for wireless communication and OS is used embedded Linux that can easily implement wireless communication environment and ensure TCP/IP communication’s security. We also implement simple server to test wireless communication between embedded & wireless fault code transmission device and server in control center.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.9
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• pp.2174-2182
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• 2013

This paper analyzed the PHY technology of IEEE 802.15.7 which is a technology trend and international standard of the LED-based VLC communication system. Also, the study analyzed the complexity of the system as well as the reception performance in a visible light wireless channel environment by analyzing detailed technology of PHY I mode and designing the RS code and block interleaver. According to the result, concerning PHY I which is operated in a single mode, it was confirmed that the complexity in designing the system was higher compared with an environment of the transmission of a short massage. Also it was confirmed that in a multi-path visible light channel environment, the reception SNR=1.5dB was required additionally.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.445-447
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• 1997

In this paper a remote monitoring and control system using Modem for UPS (Uninterruptible Power Supply) is proposed. The conventional remote monitoring system for UPS is used to local remote monitoring system by RS232 or RS485 communication code. But recently. the system is changed to wide remote monitoring and control system using Modem for quick analysis of errors, correction of errors, report of errors and other user-friendly functions. In this study, we designed and develope system which is able to control UPS an monitor errors, statuses, actual values transmitted from UPSs of each site.

• Computers and Concrete
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• v.21 no.4
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• pp.441-449
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• 2018

FE models for complex or large-scaled structures that need detailed modeling of structural components are usually constructed using commercial analysis softwares. Updating of such FE model by conventional sensitivity-based methods is difficult since repeated computation for perturbed parameters and manual calculations are needed to obtain sensitivity matrix in each iteration. In this study, an FE model updating procedure avoiding such difficulties by using response surface (RS) method and a Pareto-based multiobjective optimization (MOO) was formulated and applied to FE models constructed with a commercial analysis package. The test building is a low-rise reinforced concrete building that has been seismically retrofitted. Dynamic properties of the building were extracted from vibration tests performed before and after the seismic retrofits, respectively. The elastic modulus of concrete and masonry, and spring constants for the expansion joint were updated. Two RS functions representing the errors in the natural frequencies and mode shape, respectively, were obtained and used as the objective functions for MOO. Among the Pareto solutions, the best compromise solution was determined using the TOPSIS (Technique for Order of Preference by Similarity to Ideal Solution) procedure. A similar task was performed for retrofitted building by taking the updating parameters as the stiffness of modified or added members. Obtained parameters of the existing building were reasonably comparable with the current code provisions. However, the stiffness of added concrete shear walls and steel section jacketed members were considerably lower than expectation. Such low values are seemingly because the bond between new and existing concrete was not as good as the monolithically casted members, even though they were connected by the anchoring bars.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.7
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• pp.83-90
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• 2004

This paper describes on-board decentralized data acquisition system that acquires and encodes the numerous sensor data distributed on the big flight vehicles efficiently. The system's sub-units which have one encoder unit and several remote units were designed and simulated according to the communication protocols and the control, sequence logics based on the FPGA chip. And we have made the functional verification of the acquisition, collection and formatting of remote analog and digital data for the manufactured hardwares.

• Journal of Astronomy and Space Sciences
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• v.36 no.2
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• pp.75-86
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• 2019

UV Psc is a typical RS CVn type system undergoing dynamic chromosphere activity. We performed photometric observations of the system in 2015 and secured new BVR light curves showing well-defined photometric waves. In this paper, we analyzed the light curves using Wilson-Devinney binary code and investigated the orbital period of the system. The combination of our light curve synthesis with the spectroscopic solution developed by previous investigators yielded the absolute parameters as: $M_1=1.104{\pm}0.042M_{\odot}$, $R_1=1.165{\pm}0.025R_{\odot}$, and $L_1=1.361{\pm} 0.041L_{\odot}$ for the primary star, and $M_2=0.809{\pm}0.082M_{\odot}$, $R_2=0.858{\pm}0.018R_{\odot}$, and $L_2=0.339 {\pm}0.010L_{\odot}$ for the secondary star. The eclipse timing diagram for accurate CCD and photoelectric timings showed that the orbital period may vary either in a downward parabolic manner or a quasi-sinusoidal pattern. If the latter is adopted as a probable pattern for the period change, a more plausible account for the cyclic variation may be the light time effect caused by a circumbinary object rather than an Applegate-mechanism occurring via variable surface magnetic field strengths.

• Journal of Advanced Navigation Technology
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• v.14 no.4
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• pp.545-552
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• 2010

In this paper, we study on a radio multiple sensing interface module to accurately decide serious error sources that are happened by unexpectable problems in industrial fields, in addition, we study a reliability improvement scheme to guarantee the integrity of multiple sensing data. For multiple sensing interface module, communication drivers such as USART, TWI, ADC and GPIO-I2C are implemented. to improve the transmission reliability, reed-Solomon code is used. From the simulation result of this system in indoor environment, we confirm that the reliability of RS coded data is improved about 5 times than uncoded data. Moreover, we prove that multiple sensing interface module is suitable to diagnose error sources of industrial automaton equipment.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.37 no.1
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• pp.66-75
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• 2000

In this paper, we present the efficient image transmission system using designed source-channel combined coder in W-CDMA mobile communication system. In proposed schemes, we decompose the wavelet transformed hierarchical band-images into some types of different size blocks which have different properties in error sensitivity. The RS(Reed-Solomon) coder with different coding rate is used for each decomposed source blocks which has different importance. In addition, we combine retransmitted error frames in Truncated Hybrid Type I ARQ. The proposed algorithm shows efficient image transmission methods because it is not much degraded in PSNR compared with the existing not combined source-channel coder in erroneous wireless channel.