An empirical study of data collection protocols for wireless sensor networks

In the past few years, numerous data collection protocols have been developed for wireless sensor networks (WSNs). However, there has been no comparison of their relative performance in realistic environments. Here we report the results of an empirical study using a Fleck3 sensor network testbed for four different data collection protocols: One phase pull Directed Diffusion (DD), Expected Number of Transmissions (ETX), ETX with explicit acknowledgment (ETX-eAck), and ETX with implicit acknowledgment (ETX-iAck). Our empirical study provides useful insights for future sensor network deployments. When the required application end-to-end reliability is not strict (e.g., 70%) and link quality is good, DD and ETX are the best options because of their simplicity and low routing overhead. Both ETX-eAck and ETX-iAck achieve more than 90% end-to-end reliability when the link quality is reasonable (less than 25% packet loss). When the link quality is good, ETX-iAck introduces significantly less routing overhead (up to 50%) than ETX-eAck. However, if the radio transceiver supports variable packet length, ETX-eAck can outperform ETX-iAck when the link quality is poor. The important message from this paper is that choice of data collection protocol should come after the operating environment is understood. This understanding must include the characteristics of the radio transceiver, and link loss statistics from a long-term (across seasons and weather variation) radio survey of the site.

Lessons from media reporting of natural disasters : a case study of the 2011 flash floods in Toowoomba and the Lockyer Valley

Practice-led journalism research techniques were used in this study to produce a ‘first draft of history’ recording the human experience of survivors and rescuers during the January 2011 flash flood disaster in Toowoomba and the Lockyer Valley in Queensland, Australia. The study aimed to discover what can be learnt from engaging in journalistic reporting of natural disasters. This exegesis demonstrates that journalism can be both a creative practice and a research methodology. About 120 survivors, rescuers and family members of victims participated in extended interviews about what happened to them and how they survived. Their stories are the basis for two creative outputs of the study: a radio documentary and a non-fiction book, that document how and why people died, or survived, or were rescued. Listeners and readers are taken "into the flood" where they feel anxious for those in peril, relief when people are saved, and devastated when babies, children and adults are swept away to their deaths. In undertaking reporting about the human experience of the floods, several significant elements about journalistic reportage of disasters were exposed. The first related to the vital role that the online social media played during the disaster for individuals, citizen reporters, journalists and emergency services organisations. Online social media offer reporters powerful new reporting tools for both gathering and disseminating news. The second related to the performance of journalists in covering events involving traumatic experiences. Journalists are often required to cover trauma and are often amongst the first-responders to disasters. This study found that almost all of the disaster survivors who were approached were willing to talk in detail about their traumatic experiences. A finding of this project is that journalists who interview trauma survivors can develop techniques for improving their ability to interview people who have experienced traumatic events. These include being flexible with interview timing and selecting a location; empowering interviewees to understand they don’t have to answer every question they are asked; providing emotional security for interviewees; and by being committed to accuracy. Survivors may exhibit posttraumatic stress symptoms but some exhibit and report posttraumatic growth. The willingness of a high proportion of the flood survivors to participate in the flood research made it possible to document a relatively unstudied question within the literature about journalism and trauma – when and why disaster survivors will want to speak to reporters. The study sheds light on the reasons why a group of traumatised people chose to speak about their experiences. Their reasons fell into six categories: lessons need to be learned from the disaster; a desire for the public to know what had happened; a sense of duty to make sure warning systems and disaster responses to be improved in future; personal recovery; the financial disinterest of reporters in listening to survivors; and the timing of the request for an interview. Feedback to the creative-practice component of this thesis - the book and radio documentary - shows that these issues are not purely matters of ethics. By following appropriate protocols, it is possible to produce stories that engender strong audience responses such as that the program was "amazing and deeply emotional" and "community storytelling at its most important". Participants reported that the experience of the interview process was "healing" and that the creative outcome resulted in "a very precious record of an afternoon of tragedy and triumph and the bitter-sweetness of survival".

Weather variability, tides, and Barmah Forest Virus Disease in the Gladstone region, Australia

In this study we examined the impact of weather variability and tides on the transmission of Barmah Forest virus (BFV) disease and developed a weather-based forecasting model for BFV disease in the Gladstone region, Australia. We used seasonal autoregressive integrated moving-average (SARIMA) models to determine the contribution of weather variables to BFV transmission after the time-series data of response and explanatory variables were made stationary through seasonal differencing. We obtained data on the monthly counts of BFV cases, weather variables (e.g., mean minimum and maximum temperature, total rainfall, and mean relative humidity), high and low tides, and the population size in the Gladstone region between January 1992 and December 2001 from the Queensland Department of Health, Australian Bureau of Meteorology, Queensland Department of Transport, and Australian Bureau of Statistics, respectively. The SARIMA model shows that the 5-month moving average of minimum temperature (β = 0.15, p-value < 0.001) was statistically significantly and positively associated with BFV disease, whereas high tide in the current month (β = −1.03, p-value = 0.04) was statistically significantly and inversely associated with it. However, no significant association was found for other variables. These results may be applied to forecast the occurrence of BFV disease and to use public health resources in BFV control and prevention.

Cross-correlations between weather variables in Australia

The information on climate variations is essential for the research of many subjects, such as the performance of buildings and agricultural production. However, recorded meteorological data are often incomplete. There may be a limited number of locations recorded, while the number of recorded climatic variables and the time intervals can also be inadequate. Therefore, the hourly data of key weather parameters as required by many building simulation programmes are typically not readily available. To overcome this gap in measured information, several empirical methods and weather data generators have been developed. They generally employ statistical analysis techniques to model the variations of individual climatic variables, while the possible interactions between different weather parameters are largely ignored. Based on a statistical analysis of 10 years historical hourly climatic data over all capital cities in Australia, this paper reports on the finding of strong correlations between several specific weather variables. It is found that there are strong linear correlations between the hourly variations of global solar irradiation (GSI) and dry bulb temperature (DBT), and between the hourly variations of DBT and relative humidity (RH). With an increase in GSI, DBT would generally increase, while the RH tends to decrease. However, no such a clear correlation can be found between the DBT and atmospheric pressure (P), and between the DBT and wind speed. These findings will be useful for the research and practice in building performance simulation.

A Method of Preparing Future Hourly Weather Data for the Study of Global Warming Impact on the Built Environment

The dynamic interaction between building systems and external climate is extremely complex, involving a large number of difficult-to-predict variables. In order to study the impact of global warming on the built environment, the use of building simulation techniques together with forecast weather data are often necessary. Since all building simulation programs require hourly meteorological input data for their thermal comfort and energy evaluation, the provision of suitable weather data becomes critical. Based on a review of the existing weather data generation models, this paper presents an effective method to generate approximate future hourly weather data suitable for the study of the impact of global warming. Depending on the level of information available for the prediction of future weather condition, it is shown that either the method of retaining to current level, constant offset method or diurnal modelling method may be used to generate the future hourly variation of an individual weather parameter. An example of the application of this method to the different global warming scenarios in Australia is presented. Since there is no reliable projection of possible change in air humidity, solar radiation or wind characters, as a first approximation, these parameters have been assumed to remain at the current level. A sensitivity test of their impact on the building energy performance shows that there is generally a good linear relationship between building cooling load and the changes of weather variables of solar radiation, relative humidity or wind speed.

Developing a participatory impact assessment approach and action research culture within a communication for social change organisation in Nepal

Developing an effective impact evaluation framework, managing and conducting rigorous impact evaluations, and developing a strong research and evaluation culture within development communication organisations presents many challenges. This is especially so when both the community and organisational context is continually changing and the outcomes of programs are complex and difficult to clearly identify.----- This paper presents a case study from a research project being conducted from 2007-2010 that aims to address these challenges and issues, entitled Assessing Communication for Social Change: A New Agenda in Impact Assessment. Building on previous development communication projects which used ethnographic action research, this project is developing, trailing and rigorously evaluating a participatory impact assessment methodology for assessing the social change impacts of community radio programs in Nepal. This project is a collaboration between Equal Access – Nepal (EAN), Equal Access – International, local stakeholders and listeners, a network of trained community researchers, and a research team from two Australian universities. A key element of the project is the establishment of an organisational culture within EAN that values and supports the impact assessment process being developed, which is based on continuous action learning and improvement. The paper describes the situation related to monitoring and evaluation (M&E) and impact assessment before the project began, in which EAN was often reliant on time-bound studies and ‘success stories’ derived from listener letters and feedback. We then outline the various strategies used in an effort to develop stronger and more effective impact assessment and M&E systems, and the gradual changes that have occurred to date. These changes include a greater understanding of the value of adopting a participatory, holistic, evidence-based approach to impact assessment. We also critically review the many challenges experienced in this process, including:----- • Tension between the pressure from donors to ‘prove’ impacts and the adoption of a bottom-up, participatory approach based on ‘improving’ programs in ways that meet community needs and aspirations.----- • Resistance from the content teams to changing their existing M&E practices and to the perceived complexity of the approach.----- • Lack of meaningful connection between the M&E and content teams.----- • Human resource problems and lack of capacity in analysing qualitative data and reporting results.----- • The contextual challenges, including extreme poverty, wide cultural and linguistic diversity, poor transport and communications infrastructure, and political instability.----- • A general lack of acceptance of the importance of evaluation within Nepal due to accepting everything as fate or ‘natural’ rather than requiring investigation into a problem.

Airwaves: 100 years of radio

Music composition using prominent broadcast speeches across the whole twentieth century in commemoration of the centenary of Marconi's first transatlantic radio transmission. The work is based on creating music from the found objects of melody derived from spoken intonation. Recordings of the speeches are accompanied throughout by live instrumental music.