• Nuclear Engineering and Technology
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• v.42 no.1
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• pp.37-46
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• 2010

The development of advanced nuclear fuel cycle(ANFC) technology is essential to meet the national mission for energy independence via a nuclear option in Korea. The action target is to develop environmentally friendly, cost-effective measures to reduce the burden of long term disposal. The proper scenarios regarding potential radionuclide release from a repository have been developed in this study based on the advanced korean Reference Disposal System(A-KRS). To predict safety for the various scenarios, a new assessment code based on the GoldSim software has also been developed. Deterministic analysis indicates an environmental benefit from the ANFC as long as the solid waster from the ANFC act as a proper barrier.

• Journal of Communications and Networks
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• v.4 no.3
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• pp.170-175
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• 2002

An optical fiber code-division multiple-access (CDMA) network is proposed in which encoding is based on the use of concatenated sequences of relatively large weight. The first short component sequence in the concatenated sequence permits realistic electronic encoding of each data bit. The chips of this sequence are then all-optically encoded at substantially higher rate. In spite of the relatively large weight of the sequence the all-optical encoder is practical by virtue of the shortness of the component sequences. The use of Gold and Lempel sequences as component sequences for generating the concatenated sequences is studied and the bit-error rate (BER) performance of the proposed system is presented as a function of the received optical power with the number of simultaneous users as parameter.

• Journal of Positioning, Navigation, and Timing
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• v.13 no.1
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• pp.1-13
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• 2024

In this paper, we investigate the signal design of six (USA, EU, Russia, China, Japan, and India) countries for Global Navigation Satellite Systems (GNSS). Recently, a navigation satellite system that is capable of high-precision and reliable Positioning, Navigation, Timing (PNT) services has been developed. Prior to system design, a survey of the signal design for other GNSS systems should precede to ensure compatibility and interoperability with other GNSS. The signal design includes carrier frequency, Pseudorandom Noise (PRN) code, modulation, navigation service, etc. Specifically, GNSS is allocated L1, L2, and L5 bands, with recent additions of the L6 and S bands. GNSS uses PRN code (such as Gold, Weil, etc) to distinguish satellites that transmit signals simultaneously on the same frequency band. For modulation, both Binary Phase Shift Keying (BPSK) and Binary Offset Carrier (BOC) have been widely used to avoid collision in the frequency spectrum, and alternating BOCs are adopted to distinguish pilot and data components. Through the survey of other GNSS' signal designs, we provide insights for guiding the design of new satellite navigation systems.

• IEIE Transactions on Smart Processing and Computing
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• v.3 no.4
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• pp.181-190
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• 2014

This paper reports a cognitive radio network architecture based on overloaded multicarrier direct sequence code division multiple access (O-MC-DS-CDMA). The O-MC-DSCDMA technique combines CDMA with a multicarrier modulation technique to overcome the channel fading effects. In this technique, secondary users are enabled to share the available bandwidth with the existing primary users. Two sets of orthogonal Gold codes are used to support the primary and secondary users simultaneously. The orthogonality between the spreading codes is lost due to the non-zero cross correlation between the codes and the timing synchronization error in the uplink transmission, which causes interference between primary and secondary users. This paper proposes two modified hybrid parallel/successive interference cancellation techniques for primary and secondary user base station receivers with multiple antennas to suppress the interference among users. Interference among the same group of users is cancelled by parallel interference cancellation and the interference among groups is cancelled using successive interference cancellation. The simulation results confirmed that the proposed modified interference cancellation techniques show better BER performance over conventional interference cancellation techniques.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.11A
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• pp.1086-1095
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• 2007

This paper proposes a novel non-coherent TOA estimation scheme using multiple correlation process on the existence of multiple simultaneously operating piconets (SOPs). Impulse radio-ultra wideband (IR-UWB) based on direct sequence spread spectrum (DSSS) using Gold sequence is employed in order to discriminate each piconet. In order to enhance the characteristic of correlation, this paper presents the method of multiple mask operation (MMO). The time of arrival (TOA) of direct line of sight (DLOS) path is estimated via two step coarse/fine timing detection. To verify the performance of proposed scheme, two distinct channel models approved by IEEE 802.15.4a Task Group (TG) are considered. According to the simulation results, it could conclude that the proposed scheme have performed better performance than the conventional method well even in densed indoor multi-path environment as well as in the existence of multiple SOPs.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.8A
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• pp.598-606
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• 2003

In this paper, we analyze the performance of the PCM cell search algorithm proposed for fast cell search of WCDMA systems. In order to improve both performance and complexity of the cell search algorithm standardized for WCDMA systems the PCM scheme uses a group of the polarization codes produced by a Gold code generator. The PCM scheme only uses one synchronization channel since the polarization codes modulated on P-SCH can replace the RS codes of S-SCH. Thus, the PCM reduces the BS's transmission power since only one synchronization channel can be used, and it can also reduce the complexity of receiver as compared with the conventional one. In this paper, by defining a numerical model, we analyze the performance of the PCM cell search algorithm in terms of detection probability and mean acquisition time. Consequently, we could demonstrate that the PCM cell search algorithm is superior to the standard WCDMA cell search algorithm.

• Aerospace Engineering and Technology
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• v.8 no.1
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• pp.179-186
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• 2009

This paper describes the design and implementation for spread spectrum FTS encoder and decoder. The FTS command format is defined by 64 bit encrypted packet that contains all required information relayed between the ground and the vehicle. Encryption is accomplished using the Tripple-DES encryption algorithm in block encryption form. The proposed FTS encoder and decoder is using the Convolution Encoding and Viterbi Decoding for forward error correction. The Spread Spectrum Modulation is done using a PN code, which is 256 bit gold code. The simulation result shows that the designed FTS decoder is compatible with the designed FTS encoder.

• Journal of Arbitration Studies
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• v.26 no.3
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• pp.93-119
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• 2016

Park Tae-hwan, the Korean Olympic gold medal swimmer, was suspended for eighteen months by the International Swimming Federation (FINA) in September 2014. Park completed his suspension in March 2016, but the Korea Olympic Committee (KOC), relying on its Article 5.6, then prohibited him from joining the national team for an additional three years for the same doping violation. The KOC's penalty exceeded that provided by the World Anti-Doping Code, which governs the Olympics and most international sports federations, and contravened well-established precedent from the Court of Arbitration for Sport (CAS). The KOC, along with the Korea Swimming Federation, maintained the suspension until decisions by the Seoul Eastern District Court and CAS forced them to retract the penalty. We describe the sports regulations and arbitration decisions governing the Park case, how each side used the law to support their positions, the flaws in the KOC's legal analysis, and the case's resolutions by the Korean court and CAS. Finally, because this legal conflict has damaged the KOC's reputation, created uncertainty over the committee's doping penalties, and undercut the authority of the World Anti-Doping Code and the CAS in Korea, we recommend institutional changes in Korea's sports jurisprudence.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.11
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• pp.2147-2159
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• 1994

In this parper, the performance of trellis coded DS/SSMA system using feedforward trellis encoder with sasymmetric signal constellation are evaluated over AW(In channel. The numerical results of trellis coded 4 PSK(code rate 1/2)and 8-PSK(code rate2/3) are calculated for 2-state and 4-state cases and compared with those of the Boudreau's system using feedback trellis encoder without optimizing the signal constellation. The method of moments is employed to evaluate the multiple access interference, in conjunction with the generalized transfer function techniques for trellis code. The numerical results show that the proposed system in this paper is always better than the Boudreau's system over AWGN channel; particularly at $P_b:10$, $0.2dB\sim2.4dB$ improvement over AWGN channel are obtained.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.1 no.1
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• pp.75-78
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• 2008

In this paper, we proposed a novel encoder/decoder for an optical CDMA(code division multiple access) system by using an array of SSFBGs(superstructured fiber Bragg gratings). The feasibility of the system is shown by the simulations. The Q-factor for the system was 14.53 dB when the well-known Gold codes are used.