Frequency Diverse Array OFDM Transmitter for Secure Wireless Communication

In this reported work, the frequency diverse array concept is employed to construct an orthogonal frequency-division multiplexing (OFDM) transmitter that has the capability of securing wireless communication in free space directly in the physical-layer without the need for mathematical encryption. The characteristics of the proposed scheme in terms of its secrecy performance are validated via bit error rate simulation under both high and low signal to noise ratio scenarios using the IEEE 802.11 OFDM physical-layer specification.

Participation of Smallholders in Agroforestry Agri-Environmental Scheme: A lesson from the rural Mount Kenya region

The likelihood of smallholder farmers not participating in agroforestry agri-environmental schemes and payments for ecosystem services (PES) may be due to limited farmland endowment and formal credit constraints. These deficits may lead to an ‘exclusive club’ of successful farmers, which are not necessarily poor, enjoying the benefits of agri-environmental schemes and PES although agrienvironmental schemes and PES have been devised as a means of fostering rural sustainable development and improving the livelihood of poor smallholder farmers. Smallholder farmers in parts of rural Kenya continue to enroll in ‘The International Small Group Tree Planting Programme’ (TIST), an agri-environmental scheme, promoting agroforestry, carbon sequestration and conservation agriculture (CA). The question remains if these farmers are really poor? This study examines factors that determine the participation of smallholder farmers in TIST in parts of rural Kenya. We use survey data compiled in 2013 on 210 randomly selected smallholder farmers from Embu, Meru and Nanyuki communities; the sample consists of TIST and non-TIST members. A random utility model and logit regression were used to test a set of non-monetary and monetary factors that influence participation in the TIST. The utility function is conceptualized to give non-monetary factors, particularly the common medium of communication in rural areas – formal and informal – a central role. Furthermore, we investigate other factors (incl. credit accessibility and interest rate) that reveal the nature of farmers participating in TIST. The findings suggest that spread of information via formal and informal networks is a major driver of participation in the TIST program. Furthermore, variables such credit constrains, age and labour supply positively correlate with TIST participation, while for education the opposite is true. It is important to mention that these correlations, although somewhat consistent, were all found to be weak. The results indicate that participation in the TIST program is not influenced by farm size; therefore we argue that the TIST scheme is NOT an ‘exclusive club’ comprising wealthy and successful farmers. Older farmers’ being more likely to join the TIST is an argument for their long- rather than widely assumed short-term planning horizon and a new contribution to the literature. Given the importance of poverty alleviation and climate smart agriculture in developing countries, sustainable policy should strengthening the social and human capital as well as informal networks in rural areas. Extension services should effectively communicate benefits to less educated and credit constrained farmers.

The effectiveness of disaster risk communication: a systematic review of intervention studies

INTRODUCTION: A disaster is a serious disruption to the functioning of a community that exceeds its capacity to cope within its own resources. Risk communication in disasters aims to prevent and mitigate harm from disasters, prepare the population before a disaster, disseminate information during disasters and aid subsequent recovery. The aim of this systematic review is to identify, appraise and synthesise the findings of studies of the effects of risk communication interventions during four stages of the disaster cycle.

METHODS: We searched the Cochrane Central Register of Controlled Trials, Embase, MEDLINE, PsycInfo, Sociological Abstracts, Web of Science and grey literature sources for randomised trials, cluster randomised trials, controlled and uncontrolled before and after studies, interrupted time series studies and qualitative studies of any method of disaster risk communication to at-risk populations. Outcome criteria were disaster-related knowledge and behaviour, and health outcomes.

RESULTS: Searches yielded 5,224 unique articles, of which 100 were judged to be potentially relevant. Twenty-five studies met the inclusion criteria, and two additional studies were identified from other searching. The studies evaluated interventions in all four stages of the disaster cycle, included a variety of man-made, natural and infectious disease disasters, and were conducted in many disparate settings. Only one randomised trial and one cluster randomised trial were identified, with less robust designs used in the other studies. Several studies reported improvements in disaster-related knowledge and behaviour.

DISCUSSION: We identified and appraised intervention studies of disaster risk communication and present an overview of the contemporary literature. Most studies used non-randomised designs that make interpretation challenging. We do not make specific recommendations for practice but highlight the need for high-quality randomised trials and appropriately-analysed cluster randomised trials in the field of disaster risk communication where these can be conducted within an appropriate research ethics framework.