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An efficient technique for obtaining a variable length code (VLC) resistant to synchronization loss due to channel errors is proposed. Bit errors in the channel lead to incorrect decoding of a VLC and result in error states for continuous codewords. In this paper first a precise value is found for assessing the ability of a VLC to recover synchronization from the error states. Next a new transformation for converting a code into another of the same efficiency (equivalent transformation) is introduced, and several VLCs with an identical efficiency are compared through estimation of synchronization recovery in order to find an error-resistant VLC. Based on the equivalent transformation, an efficient method for finding an error-resistant VLC with high recovery performance from among multiple VLCs is described.

Miombo woodlands in Southern Africa are experiencing accelerated changes due to natural and anthropogenic disturbances. In order to formulate sustainable woodland management strategies in the Miombo ecosystem, timely and up-to-date land cover information is required. Recent advances in remote sensing technology have improved land cover mapping in tropical evergreen ecosystems. However, woodland cover mapping remains a challenge in the Miombo ecosystem. The objective of the study was to evaluate the performance of decision trees (DT), random forests (RF), and support vector machines (SVM) in the context of improving woodland and non-woodland cover mapping in the Miombo ecosystem in Zimbabwe. We used Multidate Landsat 8 spectral and spatial dependence (Moran's I) variables to map woodland and non-woodland cover. Results show that RF classifier outperformed the SVM and DT classifiers by 4% and 15%, respectively. The RF importance measures show that multidate Landsat 8 spectral and spatial variables had the greatest influence on class-separability in the study area. Therefore, the RF classifier has potential to improve woodland cover mapping in the Miombo ecosystem.

Tsunami vertical evacuation is an important strategy for enhancing disaster preparedness because it provides an alternative to evacuation inland or to high ground in areas at risk of local tsunami. A large number of tsunami vertical evacuation buildings provided safe refuge in the inundation zone during and immediately after the Great East Japan tsunami on March 11th2011. This paper discusses observations of such buildings in connection with themes that arose during semi-structured interviews with local disaster prevention and emergency services officials in Iwate and Miyagi Prefectures in October 2011. The implementation of key factors in the development of tsunami vertical evacuation strategies are assessed with reference to previously published guidelines, enabling lessons to be applied in the current and future development of such strategies internationally. The most important factors for designating tsunami vertical evacuation buildings are that they be reinforced concrete construction with sufficient height in relation to inundation depth. Also important to the success of such vertical evacuation strategies are community engagement, building owner agreement, consistent and clear signage, 24-hour access and evacuee welfare.