• Journal of Korean Society of Transportation
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• v.14 no.3
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• pp.143-154
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• 1996

Since chevron alignment sign provides a user with information of road's alignment, it plays an important role in improving the safety aspects of the highway. Currently, it is installed without reasonable design specifications and maintained under insufficient labor and working time. This study, therefore, reviewed the current specifications involving design, installation, shape, and color and several alternatives were generated. The readibility and visibility were chosen as measure of effectiveness to compass these alternatives. Furthermore, spacing of sign was evaluated. The field study resulted that yellow background with black sign was more realible and visible than the other alternatives.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.578-580
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• 2009

Wireless Sensor Networks(WSNs) has been used for various applications. It is optimized to low power operation than various function and transmission reliability because of limited power by batteries. but it is necessary to guarantee of reliability for using exact data for more diversity purpose. In WSNs environment composed by multi-hop, it is guarantee to end-to-end transmission reliability based hop-by-hop reliability. however, IEEE 802.15.4 standard is not consider link-layer reliability. in this paper, we propose energy efficient Reliable Link-layer Protocol for Wireless Sensor Networks.