• Journal of Korean Academy of Nursing
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• v.36 no.8
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• pp.1295-1300
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• 2006

Purpose. The purposes of this methodologic paper are to (1) describe theoretical background in conducting research across different cultures; (2) address measurement issues related to instrument administration; and (3) provide strategies to deal with measurement issues. Methods. A thorough review of the literature was conducted. A theoretical background is provided, and examples of administering instrument in studies are described. Results. When applying an instrument to different cultures, both equivalence and bias need to be established. Three levels of equivalence, i.e., construct equivalence, measurement unit equivalence, and full score comparability, need to be explained to maintain the same concept being measured. In this paper, sources of bias in construct, method, and item are discussed. Issues related to instrument administration in a cross-cultural study are described. Conclusion. Researchers need to acknowledge various group differences in concept and/or language that include a specific set of symbols and norms. There is a need to question the philosophical and conceptual appropriateness of an assessment measure that has been conceptualized and operationalized in a different culture. Additionally, testing different response formats such as narrowing response range can be considered to reduce bias.

• Journal of information and communication convergence engineering
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• v.8 no.3
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• pp.281-288
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• 2010

This paper investigates the performance of IEEE 802.11p wireless access in vehicular environments (WAVE) system in small-scale fading models reported by Georgia Institute of Technology (Georgia Tech). We redesign the small-scale fading models to be applied to the computer simulation and develop the IEEE 802.11p WAVE physical layer simulator to provide the bit error rate and packet error rate performances. Moreover, a new channel estimator using decision directed channel estimation and linear minimum mean square error smoothing is proposed in order to improve the performance of the conventional least square channel estimator using two identical long training symbols. The simulation results are satisfactorily coincident with the scenarios of Georgia Tech report, and the proposed channel estimator significantly outperforms the conventional channel estimator.

• Journal of Communications and Networks
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• v.7 no.3
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• pp.284-293
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• 2005

A critical issue in applications involving networks of wireless sensors is their ability to synchronize, and mitigate the fading propagation channel effects. Especially when distributed 'slave' sensors (nodes) reach-back to communicate with the 'master' sensor (gateway), low power cooperative schemes are well motivated. Viewing each node as an antenna element in a multi-input multi-output (MIMO) multi-antenna system, we design pilot patterns to estimate the multiple carrier frequency offsets (CFO), and the multiple channels corresponding to each node-gateway link. Our novel pilot scheme consists of non-zero pilot symbols along with zeros, which separate nodes in a time division multiple access (TDMA) fashion, and lead to low complexity schemes because CFO and channel estimators per node are decoupled. The resulting training algorithm is not only suitable for wireless sensor networks, but also for synchronization and channel estimation of single- and multi-carrier MIMO systems. We investigate the performance of our estimators analytically, and with simulations.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.8A
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• pp.1179-1186
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• 1999

Multi-carrier CDMA technique is more attractive in wireless communication system. It can support the effect of frequency diversity with higher spectral efficiency. In this paper, pilot symbol structure was proposed to estimate chann디 paramenters for MC-CDMA system and we analyzed the perfoemance of proposed MC-CDMA which compensates the received signals using the pilot symbols for link transmission. At first, we proposed the new method of pilot's usage for reverse link transmission that can distinguish accessing users whose signals undergo diggerent channels. And we analyzed the performance of coherent MC-CDMA reception using estimated channel parameters

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.8A
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• pp.1156-1162
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• 1999

In this paper, the problem of decoding transmitted data sequence with diversity reception in the presence of nondelective fading is studied. The expection maximizaton (EM) algorithm is employed to derive an interactive algorithm. The algorithm performs block-by-block coherent decoding with the aid of pilot symbols. It is shown that the complexity of the algorithm grows linearly as a function of sequence length. The performance of the algorithm is shown to better than that of the conventional pilot symbol aided (PSI) algorithm. Simulation results are presented to assess the performance of the algorithm and the results are compared with that of the conventional PSI alforithm.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.4A
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• pp.426-433
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• 2008

In this paper, we present a method to improve the performance of the four transmit antenna quasi-orthogonal space-time block code (STBC) in the coded system. For the four transmit antenna case, the quasi-orthogonal STBC consists of two symbol groups which are orthogonal to each other, but intra group symbols are not. In uncoded system with the matched filter detection, constellation rotation can improve the performance. However, in coded systems, its gain is absorbed by the coding gain especially for lower rate code. We propose an iterative decoding method to improve the performance of quasi-orthogonal codes in coded systems. With conventional quasi-orthogonal STBC detection, the joint ML detection can be improved by iterative processing between the demapper and the decoder. Simulation results shows that the performance improvement is about 2dB at 1% frame error rate.

• Proceedings of the IEEK Conference
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• 2009.05a
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• pp.9-11
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• 2009

It is well-known that the performance of turbo codes can be improved by allocating different energies per code symbol. In this paper, based on this observation, we propose a joint encoding and modulation scheme for quadrature amplitude modulated turbo code systems. In the proposed scheme, the amount of energy difference between the turbo coded symbols is optimized by optimizing the constellation of quadrature amplitude modulation(QAM). The proposed scheme offers better coding gain compared to the conventional combination of binary turbo code and QAM at the bit error rate of $10^{-5}$.

• IEIE Transactions on Smart Processing and Computing
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• v.6 no.4
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• pp.292-298
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• 2017

The complexity of image compression algorithms has increased in order to improve image compression efficiency. One way to resolve high computational complexity is parallel processing. However, entropy coding, which is lossless compression, does not fit into the parallel processing form because of the correlation between consecutive symbols. This paper proposes a new application-specific instruction set processor (ASIP) platform by adding new context-adaptive binary arithmetic coding (CABAC) instructions to the existing platform to quickly process a variety of entropy coding. The newly added instructions work without conflicts with all other existing instructions of the platform, providing the flexibility to handle many coding standards with fast processing speeds. CABAC software is implemented for High Efficiency Video Coding (HEVC) and the performance of the proposed ASIP platform was verified with a field programmable gate array simulation.

• Journal of Environmental Science International
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• v.18 no.1
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• pp.73-86
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• 2009

This research aims to find processes for developing the design language for the visual notes and design meaning of street furnitures. The result of this study are as follows. 1) The design language implies to get how to represent condensed symbols of the street furnitures. 2) The configuration of the street furnitures has their visual note and design meaning of community identity, represented their own detail design languages. 3) The detail design languages are useful to solve the matters of what design elements of the street furnitures can be composed of the visual notes and design meaning. 4) The detail design languages can be applied to the pattern of tools of Microsoft Office Word.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.10
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• pp.120-131
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• 1997

This paper prsents a new method that automatically recognizes the dimension lines (consisting of shape lines, tail lines and extension lines) from the mechanical drawings. In the proposed method, the object and closed-loop symbols are separated from the character-free drawings. Then the object lines and interpretation lines are vectorized by using several techniques such as thinning, line-vectorization, and vector-clustering. Finally, after recognizing arrowheads by using pattern matching, we recognize dimension lines from interpretation lines by using arrohead's directional vector and centroid. By using the methods of geometric modeling and mathematical operation, the proposed method readility recognizes the dimension lines from complex drawings. Experimental resuls are presented, which are obtained by applying the proposed method to drawings drawn in compliance with the KS drafting standard.