Experimental studies of wireless communication and GNSS kinematic positioning performance in high-mobility vehicle environments

In order to support intelligent transportation system (ITS) road safety applications such as collision avoidance, lane departure warnings and lane keeping, Global Navigation Satellite Systems (GNSS) based vehicle positioning system has to provide lane-level (0.5 to 1 m) or even in-lane-level (0.1 to 0.3 m) accurate and reliable positioning information to vehicle users. However, current vehicle navigation systems equipped with a single frequency GPS receiver can only provide road-level accuracy at 5-10 meters. The positioning accuracy can be improved to sub-meter or higher with the augmented GNSS techniques such as Real Time Kinematic (RTK) and Precise Point Positioning (PPP) which have been traditionally used in land surveying and or in slowly moving environment. In these techniques, GNSS corrections data generated from a local or regional or global network of GNSS ground stations are broadcast to the users via various communication data links, mostly 3G cellular networks and communication satellites. This research aimed to investigate the precise positioning system performances when operating in the high mobility environments. This involves evaluation of the performances of both RTK and PPP techniques using: i) the state-of-art dual frequency GPS receiver; and ii) low-cost single frequency GNSS receiver. Additionally, this research evaluates the effectiveness of several operational strategies in reducing the load on data communication networks due to correction data transmission, which may be problematic for the future wide-area ITS services deployment. These strategies include the use of different data transmission protocols, different correction data format standards, and correction data transmission at the less-frequent interval. A series of field experiments were designed and conducted for each research task. Firstly, the performances of RTK and PPP techniques were evaluated in both static and kinematic (highway with speed exceed 80km) experiments. RTK solutions achieved the RMS precision of 0.09 to 0.2 meter accuracy in static and 0.2 to 0.3 meter in kinematic tests, while PPP reported 0.5 to 1.5 meters in static and 1 to 1.8 meter in kinematic tests by using the RTKlib software. These RMS precision values could be further improved if the better RTK and PPP algorithms are adopted. The tests results also showed that RTK may be more suitable in the lane-level accuracy vehicle positioning. The professional grade (dual frequency) and mass-market grade (single frequency) GNSS receivers were tested for their performance using RTK in static and kinematic modes. The analysis has shown that mass-market grade receivers provide the good solution continuity, although the overall positioning accuracy is worse than the professional grade receivers. In an attempt to reduce the load on data communication network, we firstly evaluate the use of different correction data format standards, namely RTCM version 2.x and RTCM version 3.0 format. A 24 hours transmission test was conducted to compare the network throughput. The results have shown that 66% of network throughput reduction can be achieved by using the newer RTCM version 3.0, comparing to the older RTCM version 2.x format. Secondly, experiments were conducted to examine the use of two data transmission protocols, TCP and UDP, for correction data transmission through the Telstra 3G cellular network. The performance of each transmission method was analysed in terms of packet transmission latency, packet dropout, packet throughput, packet retransmission rate etc. The overall network throughput and latency of UDP data transmission are 76.5% and 83.6% of TCP data transmission, while the overall accuracy of positioning solutions remains in the same level. Additionally, due to the nature of UDP transmission, it is also found that 0.17% of UDP packets were lost during the kinematic tests, but this loss doesn't lead to significant reduction of the quality of positioning results. The experimental results from the static and the kinematic field tests have also shown that the mobile network communication may be blocked for a couple of seconds, but the positioning solutions can be kept at the required accuracy level by setting of the Age of Differential. Finally, we investigate the effects of using less-frequent correction data (transmitted at 1, 5, 10, 15, 20, 30 and 60 seconds interval) on the precise positioning system. As the time interval increasing, the percentage of ambiguity fixed solutions gradually decreases, while the positioning error increases from 0.1 to 0.5 meter. The results showed the position accuracy could still be kept at the in-lane-level (0.1 to 0.3 m) when using up to 20 seconds interval correction data transmission.

Handbook of Critical Criminonlogy

The Routledge Handbook of Critical Criminology is a collection of original essays specifically designed to offer students, faculty, policy makers, and others an in-depth overview of the most up-to-date empirical, theoretical, and political contributions made by critical criminologists around the world. Special attention is devoted to new theoretical directions in the field, such as cultural criminology, masculinities studies, and feminist criminologies. Its diverse essays not only cover the history of critical criminology and cutting edge theories, but also the variety of research methods used by leading scholars in the field and the rich data generated by their rigorous empirical work. In addition, some of the chapters suggest innovative and realistic short- and long-term policy proposals that are typically ignored by mainstream criminology. These progressive strategies address some of the most pressing social problems facing contemporary society today, and that generate much pain and suffering for socially and economically disenfranchised people. The Handbook explores up-to-date empirical, theoretical, and political contributions, and is specifically designed to be a comprehensive resource for undergraduate and post-graduate students, researchers, and policy makers.

Managing Work, Hedonism and 'the Borderline' Between the Legal and Illegal Markets: Two Case Studies of Recreational Heavy Drug Users

In the context of cultural and/or differential ‘normalisation’ of certain forms of drug use, this article describes two case-studies of heavy recreational drug users. The daily lives of these users blur the line between the legal and the illegal; their drug trading is generally as a consumer and ‘friend of a friend’ small dealer in the low-level market. In the first case, problems with management of employment, time and financial budgeting are described; in the second case, such management is accomplished. Discussion refers to: differences between the two in relation to resources and vulnerability to risks, and to leisure/pleasure cultures of hedonism. The research agenda should pay more attention to users who seek to maintain a legitimate lifestyle but who develop problems managing work and their drug-related leisure. Understanding the consumer demand and dealing activity of such users is important in trying to develop a fuller understanding of drug markets.

The performance and politics of practice for New Graduate Nurses

The change from nursing student to Registered Nurse (RNs) is both a desirable and anticipated event for New Graduate Nurses (NGNs). Having completed their formal education, most NGNs approach the threshold of their professional career with mixed emotions. While excited about the future and eagerly awaiting the commencement of employment, many are aware that this change also signifies a time of personal upheaval, professional insecurity and further personal learning. In the nursing professions’ enthusiasm to facilitate a smooth passage for NGNs a vast literature now addresses preparation-for-practice degrees, as well as the perceived workplace deficits and support needs of NGNs. However, the importance this change from working as a student to working as a NGN is not well conceptualised, theorised or understood as this largely instrumental literature essentially reduces the problematisation of the NGN transition experience to the problematisation of the individual by identifying NGNs as ‘the’ problem. Subsequently it fails to expose or challenge the normative assumptions underpinning processes that have formerly been considered solutions, or, the impact of such processes in a workplace that frames itself as “supportive”. Conspicuously absent is an exploration of how the NGN role is performed by former students, now beginning RNs undergoing the very personal transition of “becoming registered nurses”. Using Goffman’s (1956) theorisation of performance in everyday life exploring how process and meaning in mundane interactions present themselves in the “regular” lives of people at large, and Margaret Archer’s (2000) work emphasising the significance of the inner dialogue for managing the emotions that emerge out of situations that confront us, this paper draws upon data collected during a study of NGNs’ experience of transition to practice (Malouf 2010). It focuses on an emergent understanding of the need to differentiate the performance of ‘student’ from that of ‘NGN’ role. Further, it explores how these roles have become conflated into a conceptual continuum and viewed as a slide from student to NGN performance, rather than a significant moment of change involving roles that need to be distinctly defined as a necessary precursor to enhancing and supporting the professional and personal development of beginning practitioners.

Unexpected issues and solutions: Emerge from environmental manipulation strategy

Environmental manipulation removes students from their everyday worlds to unfamiliar worlds, to facil- itate learning. This article reports that this strategy was effective when applied in a university design unit, using the tactic of immersion in the Second Life online virtual environment. The objective was for teams of stu- dents each to design a series of modules for an orbiting space station using supplied data. The changed and futuristic environment led the students to an important but previously unconsidered design decision which they were able to address in novel ways because of, rather than in spite of, the Second Life immersion.