• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.6
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• pp.1317-1322
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• 2014

This paper shows effects of tropospheric delay models and mapping functions among delay features occurred when GPS code signal is transferred for GPS Time Transfer. GPS time transfer uses CGGTTS as the international standard format. For geodetic GPS receiver, ROB has provided r2cggtts software which generates CGGTTS data from RINEX data and all laboratories participated in TAI link use this software and send the CGGTTS results periodically. Though Saastamoinen zenith path model and Niell mapping function are commonly used in space geodesy, r2cggtts software applied NATO zenith path model and CHAO mapping function to the tropospheric delay model. Hence, this paper shows effects of two tropospheric delay models by implementing Saastamoinen model and Niell mapping function for the time offset.

• International Journal of Computer Science & Network Security
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• v.23 no.3
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• pp.169-176
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• 2023

The vehicular ad hoc network (VANET) is currently an important approach to improve personal safety and driving comfort. ANEL is a MAC-based authentication scheme that offers all the advantages of MAC-based authentication schemes and overcomes all their limitations at the same time. In addition, the given scheme, ANEL, can achieve the security objectives such as authentication, privacy preservation, non-repudiation, etc. In addition, our scheme provides effective bio-password login, system key update, bio-password update, and other security services. Additionally, in the proposed scheme, the Trusted Authority (TA) can disclose the source driver and vehicle of each malicious message. The heavy traffic congestion increases the number of messages transmitted, some of which need to be secretly transmitted between vehicles. Therefore, ANEL requires lightweight mechanisms to overcome security challenges. To ensure security in our ANEL scheme we can use cryptographic techniques such as elliptic curve technique, session key technique, shared key technique and message authentication code technique. This article proposes a new efficient and light authentication scheme (ANEL) which consists in the protection of texts transmitted between vehicles in order not to allow a third party to know the context of the information. A detail of the mapping from text passing to elliptic curve cryptography (ECC) to the inverse mapping operation is covered in detail. Finally, an example of application of the proposed steps with an illustration

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.11
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• pp.1254-1261
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• 2007

Mc-OFDM(Multi code-Orthogonal Frequency Division Multiplexing) modulation has been developed for high-speed data transmission over wireless channels. However, this system suffers critical problem from relatively high PAPR(Peak to Average Power Ratio). To reduce PAPR, we suggest a new technique, called Mapping using (N+1)PSK and demonstrate the performance of mapped Mc-OFDM system. On the other side, in OFDM system, each sub-carrier experiences different fading, thus some sub-carriers may be completely lost because of deep fade. To solve a above mention problem, we propose cooperative communications that improve the reliability of sub-carriers through spatial diversity.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.1
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• pp.79-86
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• 1996

In this paper we propose an architecture for VLC(Variable Length Coder) and VLD(Variable Length Decoder) which is simple with respect to implementation point and efficient in memory. We implemented encoding and decoding circuit where we need only 7-bit address memory space for 114 MPEG1 DCT coefficients and employed minimal number of flip-flops and logics for an architecture to integrate a shift register for serial-to-parallel or parallel-to-serial conversion of the data in code mapping ROM. We obtained 50Mbps operating speed in both encoding and decoding process as the result of simulation using 0.80.8${\mu}m$ CMOS standard cells.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.388-391
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• 2017

In this study, heat transfer analysis of variable thrust control system have been conducted by using commercial CFD code and FEM code. We Carried out computational fluid dynamics analysis to obtain the temperature and convective heat transfer coefficient of hot gas of variable thrust control system. Data are used as boundary condition for heat transfer analysis using mapping method. Temperature of O-ring for sealing was predicted

• Journal of the Korean Society of Physical Medicine
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• v.19 no.1
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• pp.143-154
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• 2024

PURPOSE: The present study was conducted to improve the understanding of the Korean Standard Functional, Disability, and Health Classification (KCF) and its ease of use in the clinical domain of the musculoskeletal system by comparing, analyzing, and linking the KCF codes with items from patient-reported outcome measures (PROMs), which are currently mainly used to evaluate patients with neck, shoulder, waist, and knee pain. METHODS: The items of the most widely used PROMs, the Neck Disability Index (NDI), Disabilities of the Arm, Shoulder, and Hand (DASH) scores, Oswestry Disability Index (ODI), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and the codes of the KCF were linked by two experts according to the linking rules. RESULTS: The concordance between the items of each of the PROMs and the KCF code linked by the two experts was NDI,86.4%86.4%, DASH 83.3%, ODI 92.0%, and WOMAC 80.7%. The NDI, DASH, and WOMAC indexes were found to comprise items corresponding to physical function, activity, and participation areas, and were linked to 22, 43, and 31 KCF codes, respectively. In addition to these two areas, the ODI included items related to environmental factors and was linked to 25 codes (duplicated codes are treated as one). CONCLUSION: This research can be used by adding the KCF code to the questions of the currently used evaluation tool. This coding can be easily applied and will contribute to the easy understanding of the KCF.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.4
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• pp.127-135
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• 1994

In this paper we propose an EWLD(Enhanced Weighted Levenshtein Distance) algorithm to organize code-string pattern matching linear array processor based on the mappting to an one-dimensional array from a two-dimensional matching matrix, and design a processing element(PE) of the processor, N PEs are required instead of NS02T in the processor because of the mapping. Data input and output between PEs and all internal operations of each PE are performed in bit-serial fashion. The bit-serial operation consists of the computing of word distance (WD) by comparison and the selection of optimal code transformation path, and takes 22 clocks as a cycle. The layout of a PE is designed based on the double metal $1.5\mu$m CMOS rule. About 1,800 transistors consistute a processing element and 2 PEs are integrated on a 3mm$\times$3mm sized chip.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.2269-2270
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• 2008

Zigbee that is the wireless personal area networks communication technology for low power consumption is low-cost, low-power consumption, and small size and program code. From the present paper symbol and chip sequence of existing Zigbee module undergarment PN code generators which are a 1:1 mapping method it uses shift register and it plans the method which it proposes. The experimental result used Xilinx ISE and it measured synthesis and timing and power.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.15 no.1
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• pp.43-50
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• 1990

Using the trace mapping, we suggest the generating algorithm of non-binary GMW code sequences, to expand the ground field GF(2) into GF(p), p>2. And constructing non-binary GMW code sequences over GF(3) and GF(5), respectively, it is shown that they have the Hamming autocorrelation functions identical to m-sequences, non-linearity to improve the disadvantages of linearity, and balance properties.

• Proceedings of the Korea Multimedia Society Conference
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• 2003.05b
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• pp.49-52
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• 2003

OFDM(Orthogonal Frequency Division Multiplexing) scheme can compensate for distortions caused by multipath delay spread and reduce the burst errors caused by the Doppler effect since OFDM signals have long symbol durations. However, OFDM is required to be improved for high speed data transmission and large capacity. Therefore, coding schemes should be combined with OFDM. In this paper, it was studied that the performance of OFDM transmission scheme was improved in mobile communication channel by applying TCM, which has advantages of error correction and bandwidth efficiency. Simulation was carried out for two TCM models with different code efficient length. By mapping two models to square 16QAM, the model with the code efficient length of 2 achieved 3dB better than the other for the BER of 10/sub -3/. In conclusion, if we want to achieve a better performance with TCNA in OFDM applications, we should select a TCM with larger code efficient length.