Performance analysis of IEEE 802.11 DCF based WNCS networks

Wireless network technologies, such as IEEE 802.11 based wireless local area networks (WLANs), have been adopted in wireless networked control systems (WNCS) for real-time applications. Distributed real-time control requires satisfaction of (soft) real-time performance from the underlying networks for delivery of real-time traffic. However, IEEE 802.11 networks are not designed for WNCS applications. They neither inherently provide quality-of-service (QoS) support, nor explicitly consider the characteristics of the real-time traffic on networked control systems (NCS), i.e., periodic round-trip traffic. Therefore, the adoption of 802.11 networks in real-time WNCSs causes challenging problems for network design and performance analysis. Theoretical methodologies are yet to be developed for computing the best achievable WNCS network performance under the constraints of real-time control requirements. Focusing on IEEE 802.11 distributed coordination function (DCF) based WNCSs, this paper analyses several important NCS network performance indices, such as throughput capacity, round trip time and packet loss ratio under the periodic round trip traffic pattern, a unique feature of typical NCSs. Considering periodic round trip traffic, an analytical model based on Markov chain theory is developed for deriving these performance indices under a critical real-time traffic condition, at which the real-time performance constraints are marginally satisfied. Case studies are also carried out to validate the theoretical development.

The role of cardiopulmonary signals in the dynamics of the eye's wavefront aberrations

Abstract—The role of cardiopulmonary signals in the dynamics of wavefront aberrations in the eye has been examined. Synchronous measurement of the eye’s wavefront aberrations, cardiac function, blood pulse, and respiration signals were taken for a group of young, healthy subjects. Two focusing stimuli, three breathing patterns, as well as natural and cycloplegic eye conditions were examined. A set of tools, including time–frequency coherence and its metrics, has been proposed to acquire a detailed picture of the interactions of the cardiopulmonary system with the eye’s wavefront aberrations. The results showed that the coherence of the blood pulse and its harmonics with the eye’s aberrations was, on average, weak (0.4 ± 0.15), while the coherence of the respiration signal with eye’s aberrations was, on average, moderate (0.53 ± 0.14). It was also revealed that there were significant intervals during which high coherence occurred. On average, the coherence was high (>0.75) during 16% of the recorded time, for the blood pulse, and 34% of the time for the respiration signal. A statistically significant decrease in average coherence was noted for the eye’s aberrations with respiration in the case of fast controlled breathing (0.5 Hz). The coherence between the blood pulse and the defocus was significantly larger for the far target than for the near target condition. After cycloplegia, the coherence of defocus with the blood pulse significantly decreased, while this was not the case for the other aberrations. There was also a noticeable, but not statistically significant, increase in the coherence of the comatic term and respiration in that case. By using nonstationary measures of signal coherence, a more detailed picture of interactions between the cardiopulmonary signals and eye’s wavefront aberrations has emerged.

Sustainable urban and transport development for transportation disadvantaged : a review

Around the world, particularly in North America and Australia, urban sprawl combined with low density suburban development has caused serious accessibility and mobility problems, especially for those who do not own a motor vehicle or have access to public transportation services. Sustainable urban and transportation development is seen crucial in solving transportation disadvantage problems in urban settlements. However, current urban and transportation models have not been adequately addressed unsustainable urban transportation problems that transportation disadvantaged groups overwhelmingly encounter, and the negative impacts on the disadvantaged have not been effectively considered. Transportation disadvantaged is a multi-dimensional problem that combines demographic, spatial and transportation service dimensions. Nevertheless, most transportation models focusing on transportation disadvantage only employ demographic and transportation service dimensions and do not take spatial dimension into account. This paper aims to investigate the link between sustainable urban and transportation development and spatial dimension of the transportation disadvantage problem. The paper, for that purpose, provides a thorough review of the literature and identifies a set of urban, development and policy characteristics to define spatial dimension of the transportation disadvantage problem. This paper presents an overview of these urban, development and policy characteristics that have significant relationships with sustainable urban and transportation development and travel inability, which are also useful in determining transportation disadvantaged populations.

Orchestrating knowledge-based urban development : lessons from multimedia super corridor, Malaysia

In the era of knowledge economy, cities and regions have started increasingly investing on their physical, social and knowledge infrastructures so as to foster, attract and retain global talent and investment. Knowledge-based urban development as a new paradigm in urban planning and development is being implemented across the globe in order to increase the competitiveness of cities and regions. This chapter provides an overview of the lessons from Multimedia Super Corridor, Malaysia as one of the first large scale manifestations of knowledge-based urban development in South East Asia. The chapter investigates the application of the knowledge-based urban development concept within the Malaysian context, and, particularly, scrutinises the development and evolution of Multimedia Super Corridor by focusing on strategies, implementation policies, infrastructural implications, and agencies involved in the development and management of the corridor. In the light of the literature and case findings, the chapter provides generic recommendations, on the orchestration of knowledge-based urban development, for other cities and regions seeking such development.

Out of touch? On the lack of emotional support over the mobile phone

Findings from an Australian case study of adult women expose general, light and basic use of mobile phones. Participants used their mobile phone mainly for coordination and to a lesser extent for practicing intrinsic interactions motivated by emotional support purposes. This paper focuses on social and emotional support over the mobile phone. Though crucial to individuals, emotional support seems to be a neglected area of research among mobile communication studies, all the more so when focusing on adult women. This study addresses this literature gap. The empirical findings are based on a case study of 26 women over 35 years of age residing in one coastal Australian town. The research design included a combination of quantitative and qualitative methods. This paper examines the communication methods adult women use for social and emotional support, and analyses reasons and social implications of this limited intrinsic communication use pattern over the mobile phone.

Real estate 2.0 : towards a value ecology?

This paper anatomises emerging developments in online community engagement in a major global industry: real estate. Economists argue that we are entering a ‘social network economy’ in which ‘complex social networks’ govern consumer choice and product value. In the light of this, organisations are shifting from thinking and behaving in the conventional ‘value chain’ model--in which exchanges between firms and customers are one-way only, from the firm to the consumer--to the ‘value ecology’ model, in which consumers and their networks become co-creators of the value of the product. This paper studies the way in which the global real estate industry is responding to this environment. This paper identifies three key areas in which online real estate ‘value ecology’ work is occurring: real estate social networks, games, and locative media / augmented reality applications. Uptake of real estate applications is, of course, user-driven: the paper not only highlights emerging innovations; it also identifies which of these innovations are actually being taken up by users, and the content contributed as a result. The paper thus provides a case study of one major industry’s shift into a web 2.0 communication model, focusing on emerging trends and issues.

Civic engagement and associationalism : the impact of group membership scope versus intensity of participation

The relationship between participation in civic and political activities and membership of voluntary associations is now well established. What is less clear is the relative impacts of how much time people spend on group activities (associational intensity), and the number and type of groups that individuals are involved with (associational scope). Does it matter in terms of civic engagement, for example, whether one is a member of a quilting-circle or trade union? Does it matter whether association ‘membership’ is simply an annual payment or a major commitment of time and energy? In this article, we use a large survey to explore these questions empirically by focusing on the membership patterns and civic engagement practices of 4,001 citizens drawn from eight suburbs across Greater Melbourne, Australia. Our findings indicate that, while associational intensity is positively related to civic engagement, associational scope (the number of group memberships per person), is a more influential determinant of the level of civic and political participation. The results also suggest that while all forms of associationalism are important in terms of fostering greater levels of civic activity, not all forms have the same impact.

Optimism about safety and group-serving interpretations of safety among pedestrians and cyclists in relation to road use in general and under low light conditions

Drivers are known to be optimistic about their risk of crash involvement, believing that they are less likely to be involved in a crash than other drivers. However, little comparative research has been conducted among other road users. In addition, optimism about crash risk is conceptualised as applying only to an individual’s assessment of his or her personal risk of crash involvement. The possibility that the self-serving nature of optimism about safety might be generalised to the group-level as a cyclist or a pedestrian, i.e., becoming group-serving rather than self-serving, has been overlooked in relation to road safety. This study analysed a subset of data collected as part of a larger research project on the visibility of pedestrians, cyclists and road workers, focusing on a set of questionnaire items administered to 406 pedestrians, 838 cyclists and 622 drivers. The items related to safety in various scenarios involving drivers, pedestrians and cyclists, allowing predictions to be derived about group differences in agreement with items based on the assumption that the results would exhibit group-serving bias. Analysis of the responses indicated that specific hypotheses about group-serving interpretations of safety and responsibility were supported in 22 of the 26 comparisons. When the nine comparisons relevant to low lighting conditions were considered separately, seven were found to be supported. The findings of the research have implications for public education and for the likely acceptance of messages which are inconsistent with current assumptions and expectations of pedestrians and cyclists. They also suggest that research into group-serving interpretations of safety, even for temporary roles rather than enduring groups, could be fruitful. Further, there is an implication that gains in safety can be made by better educating road users about the limitations of their visibility and the ramifications of this for their own road safety, particularly in low light.

Embracing diversity : empowering preservice teachers for teaching gifted and talented students

This study investigated preservice teachers’ perceptions for teaching and sustaining gifted and talented students while developing, modifying and implementing activities to cater for the diverse learner. Participants were surveyed at the end of a gifted and talented education program on their perceptions to differentiate the curriculum for meeting the needs of the student (n=22). SPSS data analysis with the five-part Likert scale indicated these preservice teachers agreed or strongly agreed they had developed skills in curriculum planning (91%) with well-designed activities (96%), and lesson preparation skills (96%). They also claimed they were enthusiastic for teaching (91%) and understanding of school practices and policies (96%). However, 46% agreed they had knowledge of syllabus documents with 50% claiming an ability to provide written feedback on student’s learning. Furthermore, nearly two-thirds suggested they had educational language from the syllabus and effective student management strategies. Preservice teachers require more direction on how to cater for diversity and begin creating sustainable societies by building knowledge from direct GAT experiences. Designing diagnostic surveys associated with university coursework can be used to determine further development for specific preservice teacher development in GAT education. Preservice teachers need to create opportunities for students to realise their potential by involving cognitive challenges through a differentiated curriculum. Differentiation requires modification of four primary areas of curriculum development (Maker, 1975) content (what we teach), process (how we teach), product (what we expect the students to do or show) and learning environment (where we teach/our class culture). Ashman and Elkins (2009) and Glasson (2008) emphasise the need for preservice teachers, teachers and other professionals to be able to identify what gifted and talented (GAT) students know and how they learn in relation to effective teaching. Glasson (2008) recommends that educators keep up to date with practices in pedagogy, support, monitoring and profiling of GAT students to create an environment conducive to achieving. Oral feedback is one method to communicate to learners about their progress but has advantages and disadvantages for some students. Oral feedback provides immediate information to the student on progress and performance (Ashman & Elkins, 2009). However, preservice teachers must have clear understandings of key concepts to assist the GAT student. Implementing teaching strategies to engage innovate and extend students is valuable to the preservice teacher in focusing on GAT student learning in the classroom (Killen, 2007). Practical teaching strategies (Harris & Hemming, 2008; Tomlinson et al., 1994) facilitate diverse ways for assisting GAT students to achieve learning outcomes. Such strategies include activities to enhance creativity, co-operative learning and problem-solving activities (Chessman, 2005; NSW Department of Education and Training, 2004; Taylor & Milton, 2006) for GAT students to develop a sense of identity, belonging and self esteem towards becoming an autonomous learner. Preservice teachers need to understand that GAT students learn in a different way and therefore should be assessed differently. Assessment can be through diverse options to demonstrate the student’s competence, demonstrate their understanding of the material in a way that highlights their natural abilities (Glasson, 2008; Mack, 2008). Preservice teachers often are unprepared to assess students understanding but this may be overcome with teacher education training promoting effective communication and collaboration in the classroom, including the provision of a variety of assessment strategies to improve teaching and learning (Callahan et al., 2003; Tomlinson et al., 1994). It is also critical that preservice teachers have enthusiasm for teaching to demonstrate inclusion, involvement and the excitement to communicate to GAT students in the learning process (Baum, 2002). Evaluating and reflecting on teaching practices must be part of a preservice teacher’s repertoire for GAT education. Evaluating teaching practices can assist to further enhance student learning (Mayer, 2008). Evaluation gauges the success or otherwise of specific activities and teaching in general (Mayer, 2008), and ensures that preservice teachers and teachers are well prepared and maintain their commitment to their students and the community. Long and Harris (1999) advocate that reflective practices assist teachers in creating improvements in educational practices. Reflective practices help preservice teachers and teachers to improve their ability to pursue improved learning outcomes and professional growth (Long & Harris, 1999). Context This study is set at a small regional campus of a large university in Queensland. As a way to address departmental policies and the need to prepare preservice teachers for engaging a diverse range of learners (see Queensland College of Teachers, Professional Standards for Teachers, 2006), preservice teachers at this campus completed four elective units within their Bachelor of Education (primary) degree. The electives include: 1. Middle years students and schools 2. Teaching strategies for engaging learners 3. Teaching students with learning difficulties, and 4. Middle-years curriculum, pedagogy and assessment. In the university-based component of this unit, preservice teachers engaged in learning about middle years students and schools, and gained knowledge of government policies pertaining to GAT students. Further explored within in this unit was the importance of: collaboration between teachers, parents/carers and school personnel in supporting middle years GAT students; incorporating challenging learning experiences that promoted higher order thinking and problem solving skills; real world learning experiences for students and; the alignment and design of curriculum, pedagogy and assessment that is relevant to the students development, interests and needs. The participants were third-year Bachelor of Education (primary) preservice teachers who were completing an elective unit as part of the middle years of schooling learning with a focus on GAT students. They were assigned one student from a local school. In the six subsequent ninety minute weekly lessons, the preservice teachers were responsible for designing learning activities that would engage and extend the GAT students. Furthermore, preservice teachers made decisions about suitable pedagogical approaches and designed the assessment task to align with the curriculum and the developmental needs of their middle years GAT student. This research aims to describe preservice teachers’ perceptions of their education for teaching gifted and talented students.

Testing for accountability

Current graduates in education are entering a very different profession to the one in which most of their “baby-boomer” colleagues started. It is a profession in which accountability and national high-stakes testing (e.g. NAPLAN) have become catch-cries, and where the interpretation and use of educational data is an additional challenge. This has led to schools focusing on performance, and teachers now have to analyse test data and apply the findings to their teaching.

Grade A Taipei junior high school principals’ self-reported leadership practices

The principal’s leadership and curriculum development are considered the core elements for creating a high performing junior high school. In Taiwan, mathematics curriculum reform has been an ongoing topic since 1994. The pedagogy, classroom interactions, and the underlying philosophy of mathematics education have varied with different versions of guidelines. These changes inevitably increase the requirement for principals’ leadership in order to effectively implement the curriculum reform. Principals’ leadership is essential to the success of the implementation in their school. This study aimed to explore and identify the leadership of junior high school principals whose schools had been judged by the Taipei City Government as Grade A junior high schools. Principals’ implementations of the reformed mathematics curriculum were used as examples to generate insights of their leadership. This study drew upon a multiple-case study approach. Data were collected from interviews, observations, and documentations. Bass and Avolio’s (1997) full range leadership theory provided a structure for gaining insight into these principals’ leadership practices. Five Grade A Taipei junior high school principals participated and shared their leadership concepts and experiences. Findings revealed that the leadership preferences of the five principles varied considerably. Management by exception-active, contingent reward, individualised consideration, and idealised influence were Grade A Taipei junior high school principals’ preferred leadership practices. In addition, principals’ leadership strategies associated with these practices were identified. These principals had adopted a range of leadership strategies according to the staff and school needs. Results of this study have implications for both Taiwanese principals and education departments. Principals can enhance their leadership by gaining more understanding about the Grade A principals’ leadership practices and strategies. Taiwanese education departments can improve school leadership training programs by focusing on these practices and strategies, which may also lead to more effective strategies for implementing national curriculum reform.

Lifestyle factors associated concurrently and prospectively with co-morbid cardiovascular disease in a population-based cohort of colorectal cancer survivors

Aims To assess self-reported lifetime prevalence of cardiovascular disease (CVD) among colorectal cancer survivors, and examine the cross-sectional and prospective associations of lifestyle factors with co-morbid CVD. Methods Colorectal cancer survivors were recruited (n = 1966). Data were collected at approximately 5, 12, 24 and 36 months post-diagnosis. Cross-sectional findings included six CVD categories (hypercholesterolaemia, hypertension, diabetes, heart failure, kidney disease and ischaemic heart disease (IHD)) at 5 months post-diagnosis. Longitudinal outcomes included the probability of developing (de novo) co-morbid CVD by 36 months post-diagnosis. Lifestyle factors included body mass index, physical activity, television (TV) viewing, alcohol consumption and smoking. Results Co-morbid CVD prevalence at 5 months post-diagnosis was 59%, and 16% of participants with no known CVD at the baseline reported de novo CVD by 36 months. Obesity at the baseline predicted de novo hypertension (odds ratio [OR] = 2.20, 95% confidence intervals [CI] = 1.09, 4.45) and de novo diabetes (OR = 6.55, 95% CI = 2.19, 19.53). Participants watching >4 h of TV/d at the baseline (compared with <2 h/d) were more likely to develop ischaemic heart disease by 36 months (OR = 5.51, 95% CI = 1.86, 16.34). Conclusion Overweight colorectal cancer survivors were more likely to suffer from co-morbid CVD. Interventions focusing on weight management and other modifiable lifestyle factors may reduce functional decline and improve survival.

Aligning communication, cultural and media studies research and scholarship with industry and policy : Australian instances

This article reflects on aspects of what is claimed to be the distinctiveness of Australian communication, cultural and media studies, focusing on two cases – the cultural policy debate in the 1990s, and the concept of creative industries in the 2000s – and the relations between them, which highlight the alignment of research and scholarship with industry and policy and with which the author has been directly involved. Both ‘moments’ have been controversial; the three main lines of critique of such alignment of research and scholarship with industry and policy (its untoward proximity to tenets of the dominant neo-liberal ideology; the evacuation of cultural value by the economic; and the possible loss of critical vocation of the humanities scholar) are debated.

Internal market orientation and market-oriented behaviours

Purpose: The purpose of this empirical paper is to investigate internal marketing from a behavioural perspective. The impact of internal marketing behaviours, operationalised as an internal market orientation (IMO), on employees’ marketing and other in-role behaviours (IRB) were examined. ---------- Design/methodology/approach: Survey data measuring IMO, market orientation and a range of constructs relevant to the nomological network in which they are embedded were collected from the UK retail managers. These were tested to establish their psychometric properties and the conceptual model was analysed using structural equations modelling, employing a partial least squares methodology. ---------- Findings: IMO has positive consequences for employees’ market-oriented and other IRB. These, in turn, influence marketing success. Research limitations/implications – The paper provides empirical support for the long-held assumption that internal and external marketing are related and that organisations should balance their external focus with some attention to employees. Future research could measure the attitudes and behaviours of managers, employees and customers directly and explore the relationships between them. ---------- Practical implications: Firm must ensure that they do not put the needs of their employees second to those of managers and shareholders; managers must develop their listening skills and organisations must become more responsive to the needs of their employees. ---------- Originality/value: The paper contributes to the scarce body of empirical support for the role of internal marketing in services organisations. For researchers, this paper legitimises the study of internal marketing as a route to external market success; for managers, the study provides quantifiable evidence that focusing on employees’ wants and needs impacts their behaviours towards the market.

How HCI design influences web security decisions

Even though security protocols are designed to make computer communication secure, it is widely known that there is potential for security breakdowns at the human machine interface. This paper reports on a diary study conducted in order to investigate what people identify as security decisions that they make while using the web. The study aimed to uncover how security is perceived in the individual's context of use. From this data, themes were drawn, with a focus on addressing security goals such as confidentiality and authentication. This study is the first study investigating users' web usage focusing on their self-documented perceptions of security and the security choices they made in their own environment.