• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.11C
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• pp.1581-1591
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• 2004

In this paper, we investigate the design of three low-complexity joint estimation algorithms(LJEAs) for frequency offset and carrier phase. The proposed LJEAs are based on the interpolation technique of correlation values of the received signal in frequency and phase domains. With these algorithms, the estimation ranges $\Delta$f$_{d}$${\times}$T$_{s}$ . are less than 1/2N$_{s}$ , and 1/N$_{s}$ which are comparable to conventional algorithms. The Proposed LJEAs require only 2N$_{s}$ or 4N$_{s}$ complex multiplications which are very simple compared with the conventional algorithms. Nevertheless the estimation accuracies of the LJEAs are as good as those of the conventional algorithms. Suitable areas of application include joint estimation of frequency offset and carrier phase in burst-mode digital transmission such as satellite communications.

• Journal of vocational education research
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• v.33 no.3
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• pp.37-56
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• 2014

The purpose of this study was to develop a competency model and analyze the competency needs for construction manager in D Co., Ltd.. The delphi method of 25 excellent construction managers working in D Co., Ltd. was used to develop a competency model. The results showed that there would be a construction manager competency model which consisted of 3 competency clusters, 11 competencies, and 60 key actions. Then the survey of 114 construction managers working in D Co., Ltd. was conducted to examine concurrent construct validity of the competency model for construction manager and to analyze construction managers' competency needs by using the Borich's formula and the Locus for Focus Model(LfFM). The results showed that construction managers perceived 'communication', 'risk management', 'goal orientation', 'customer orientation', and 'project management' as top five priorities of competencies for construction managers. Based upon the above results, some implications were suggested for developing construction managers' competencies and improving their performance.