Quantitative assessment of fault tolerant precision timing for electricity substations

Advanced substation applications, such as synchrophasors and IEC 61850-9-2 sampled value process buses, depend upon highly accurate synchronizing signals for correct operation. The IEEE 1588 Precision Timing Protocol (PTP) is the recommended means of providing precise timing for future substations. This paper presents a quantitative assessment of PTP reliability using Fault Tree Analysis. Two network topologies are proposed that use grandmaster clocks with dual network connections and take advantage of the Best Master Clock Algorithm (BMCA) from IEEE 1588. The cross-connected grandmaster topology doubles reliability, and the addition of a shared third grandmaster gives a nine-fold improvement over duplicated grandmasters. The performance of BMCA mediated handover of the grandmaster role during contingencies in the timing system was evaluated experimentally. The 1 µs performance requirement of sampled values and synchrophasors are met, even during network or GPS antenna outages. Slave clocks are shown to synchronize to the backup grandmaster in response to degraded performance or loss of the main grandmaster. Slave disturbances are less than 350 ns provided the grandmaster reference clocks are not offset from one another. A clear understanding of PTP reliability and the factors that affect availability will encourage the adoption of PTP for substation time synchronization.

Evaluation of Trippple : a field analysis

This paper illustrates a field research performed with a team of experts involved in the evaluation of Trippple, a system aimed at supporting the different phases of a tourist trip, in order to provide feedback and insights, both on the functionalities already implemented (that at the time of evaluation were available only as early and very unstable prototypes), and on the functionalities still to be implemented. We show how the involvement of professionals helped to focus on challenging aspects, instead of less important, cosmetic, issues and resulted profitable in terms of early feedback, issues spotted, and improvements suggested

Natural convection flow in a strong cross magnetic field with radiation

The problem of MHD natural convection boundary layer flow of an electrically conducting and optically dense gray viscous fluid along a heated vertical plate is analyzed in the presence of strong cross magnetic field with radiative heat transfer. In the analysis radiative heat flux is considered by adopting optically thick radiation limit. Attempt is made to obtain the solutions valid for liquid metals by taking Pr≪1. Boundary layer equations are transformed in to a convenient dimensionless form by using stream function formulation (SFF) and primitive variable formulation (PVF). Non-similar equations obtained from SFF are then simulated by implicit finite difference (Keller-box) method whereas parabolic partial differential equations obtained from PVF are integrated numerically by hiring direct finite difference method over the entire range of local Hartmann parameter, $xi$ . Further, asymptotic solutions are also obtained for large and small values of local Hartmann parameter $xi$ . A favorable agreement is found between the results for small, large and all values of $xi$ . Numerical results are also demonstrated graphically by showing the effect of various physical parameters on shear stress, rate of heat transfer, velocity and temperature.

Vertical infrastructure inspection using a quadcopter and shared autonomy control

This paper presents a shared autonomy control scheme for a quadcopter that is suited for inspection of vertical infrastructure — tall man-made structures such as streetlights, electricity poles or the exterior surfaces of buildings. Current approaches to inspection of such structures is slow, expensive, and potentially hazardous. Low-cost aerial platforms with an ability to hover now have sufficient payload and endurance for this kind of task, but require significant human skill to fly. We develop a control architecture that enables synergy between the ground-based operator and the aerial inspection robot. An unskilled operator is assisted by onboard sensing and partial autonomy to safely fly the robot in close proximity to the structure. The operator uses their domain knowledge and problem solving skills to guide the robot in difficult to reach locations to inspect and assess the condition of the infrastructure. The operator commands the robot in a local task coordinate frame with limited degrees of freedom (DOF). For instance: up/down, left/right, toward/away with respect to the infrastructure. We therefore avoid problems of global mapping and navigation while providing an intuitive interface to the operator. We describe algorithms for pole detection, robot velocity estimation with respect to the pole, and position estimation in 3D space as well as the control algorithms and overall system architecture. We present initial results of shared autonomy of a quadrotor with respect to a vertical pole and robot performance is evaluated by comparing with motion capture data.

Efficient solution of multiple cracks in great number using eigen COD boundary integral equations with iteration procedure

A newly developed computational approach is proposed in the paper for the analysis of multiple crack problems based on the eigen crack opening displacement (COD) boundary integral equations. The eigen COD particularly refers to a crack in an infinite domain under fictitious traction acting on the crack surface. With the concept of eigen COD, the multiple cracks in great number can be solved by using the conventional displacement discontinuity boundary integral equations in an iterative fashion with a small size of system matrix to determine all the unknown CODs step by step. To deal with the interactions among cracks for multiple crack problems, all cracks in the problem are divided into two groups, namely the adjacent group and the far-field group, according to the distance to the current crack in consideration. The adjacent group contains cracks with relatively small distances but strong effects to the current crack, while the others, the cracks of far-field group are composed of those with relatively large distances. Correspondingly, the eigen COD of the current crack is computed in two parts. The first part is computed by using the fictitious tractions of adjacent cracks via the local Eshelby matrix derived from the traction boundary integral equations in discretized form, while the second part is computed by using those of far-field cracks so that the high computational efficiency can be achieved in the proposed approach. The numerical results of the proposed approach are compared not only with those using the dual boundary integral equations (D-BIE) and the BIE with numerical Green's functions (NGF) but also with those of the analytical solutions in literature. The effectiveness and the efficiency of the proposed approach is verified. Numerical examples are provided for the stress intensity factors of cracks, up to several thousands in number, in both the finite and infinite plates.

Regulation of emissions under the carbon pricing mechanism : a case study of Australia’s coal fired electricity sector

On 1 July 2012, the carbon pricing mechanism commenced in Australia with the aim of reducing emissions and encouraging investment in clean energy. A substantial proportion of Australia’s emissions are attributable to the coal-fired electricity generation sector. This article examines whether the carbon pricing mechanism will effectively facilitate emissions reduction from the coal-fired electricity sector. Aspects analysed include the legislative constraints placed on the carbon price, the carbon pollution cap and provisions specific to the coal-fired electricity sector, such as transitional assistance. It is concluded that, in practice, the carbon pricing mechanism may not be sufficient in itself to achieve significant reduction in emissions from coal-fired electricity generation or significant investment in clean energy, and that a suite of additional regulatory measures, such as the federal Renewable Energy Target, should operate in conjunction with the mechanism.

Social signal processing for pain monitoring using a hidden conditional random field

utomatic pain monitoring has the potential to greatly improve patient diagnosis and outcomes by providing a continuous objective measure. One of the most promising methods is to do this via automatically detecting facial expressions. However, current approaches have failed due to their inability to: 1) integrate the rigid and non-rigid head motion into a single feature representation, and 2) incorporate the salient temporal patterns into the classification stage. In this paper, we tackle the first problem by developing a “histogram of facial action units” representation using Active Appearance Model (AAM) face features, and then utilize a Hidden Conditional Random Field (HCRF) to overcome the second issue. We show that both of these methods improve the performance on the task of pain detection in sequence level compared to current state-of-the-art-methods on the UNBC-McMaster Shoulder Pain Archive.

Transnational field experience : making the familiar strange

This study explores the impact of field experience in Australian primary classrooms on the developing professional identities of Malaysian pre-service teachers. This group of 24 Malaysian students are undertaking their Bachelor of Education in Teaching English as a Foreign Language (BEd TESL) at an Australian university, as part of a transnational twinning program. The globalisation of education has seen an increase in such transnational school experiences for pre-service teachers, with the aim of extending professional experience and intercultural competence by engaging in communities of practice beyond the local (Tsui 2005, Luke 2004). Despite overseas governments, such as Malaysia, having sponsored multimillion dollar twinning programs for their pre-service teachers, there is a lack of research regarding the outcomes of transnational professional practice within such programs. This study adopts a qualitative approach focusing on participants’ narratives as revealed in their reflective writing and through semi-structured interviews. Adopting a Bakhtinian framework, this research uses the concept of ‘voice’ to explore how pre-service teachers negotiate their identities as EFL teachers in response to their lived professional experiences (Bakhtin 1981, 1986). Encountering different cultural and educational practices in their transnational field experiences can lead pre-service teachers to question taken-for-granted practices that they have grown up with. This has been described as a process of making the familiar strange, and can lead to a shift in professional understandings. This study investigates how such questioning occurs and how the transnational field experience is perceived by the participants as contributing to their developing professional identities.

The correlation between electric field emission phenomenon and Schottky contact reverse bias characteristics in nanostructured systems

Two different morphologies of nanotextured molybdenum oxide were deposited by thermal evaporation. By measuring their field emission (FE) properties, an enhancement factor was extracted. Subsequently, these films were coated with a thin layer of Pt to form Schottky contacts. The current-voltage (I-V) characteristics showed low magnitude reverse breakdown voltages, which we attributed to the localized electric field enhancement. An enhancement factor was obtained from the I-V curves. We will show that the enhancement factor extracted from the I-V curves is in good agreement with the enhancement factor extracted from the FE measurements.

Analysing DBD plasma lamp intensity versus power consumption using a push-pull pulsed power supply

In this paper characteristic of a DBD (Dielectric Barrier Discharge) plasma lamp is investigated based on the lamp intensity and power consumption. A pulsed power supply with controllable parameters based on a push-pull converter is developed for lamp excitation at different voltage levels and repetition rate. The experimentations were conducted for 28 different operating points with the frequency range of 2 kHz to 15 Khz at output voltage levels of between 7.4 kV up to 13 kV. The obtained results show the feasibility of finding an optimum operation point due to nonlinear behaviour of the DBD lamp.

Business planning, innovation and performance in nascent firms

Debate about the relationships between business planning and performance has been active for decades (Bhidé, 2000; Mintzberg, 1994). While results have been inconclusive, this topic still strongly divides the research community (Brinckmann et al., 2010; Chwolka & Raith, 2011; Delmar & Shane, 2004; Frese, 2009; Gruber, 2007; Honig & Karlsson, 2004). Previous research explored the relationships between innovation and the venture creation process (Amason et al., 2006, Dewar & Dutton, 1986; Jennings et al., 2009). However, the relationships between business planning and innovation have mostly been invoked indirectly in the strategy and entrepreneurship literatures through the notion of uncertainty surrounding the development of innovation. Some posited that planning may be irrelevant due to the iterative process, the numerous changes innovation development entails and the need to be flexible (Brews & Hunt, 1999). Others suggested that planning may facilitate the achievement of goals and overcoming of obstacles (Locke and Latham, 2000), guide the venture in its allocation of resources (Delmar and Shane, 2003) and help to foster the communication about the innovation being developed (Liao & Welsh, 2008). However, the nature and extents of the relationships between business planning, innovation and performance are still largely unknown. Moreover, if the reasons why ventures should engage (Frese, 2009) –or not- (Honig, 2004) in business planning have been investigated quite extensively (Brinckmann et al., 2010), the specific value of business planning for nascent firms developing innovation is still unclear. The objective of this paper is to shed some light on these important aspects by investigating the two following questions on a large sample of random nascent firms: 1) how is business planning use over time by new ventures developing different types and degrees of innovation? 2) how do business planning and innovation impact the performance of the nascent firms? Methods & Key propositions This PSED-type study draws its data from the first three waves of the CAUSEE project where 30,105 Australian households were randomly contacted by phone using a methodology to capture emerging firms (Davidsson, Steffens, Gordon, Reynolds, 2008). This screening led to the identification of 594 nascent ventures (i.e., firms that were not operating yet at the time of the identification) that were willing to participate in the study. Comprehensive phone interviews were conducted with these 594 ventures. Likewise, two comprehensive follow-ups were organised 12 months and 24 months later where 80% of the eligible cases of the previous wave completed the interview. The questionnaire contains specific sections investigating business plans such as: presence or absence, degree of formality and updates of the plan. Four types of innovation are measured along three degrees of intensity to produce a comprehensive continuous measure ranging from 0 to 12 (Dahlqvist & Wiklund, 2011). Other sections informing on the gestation activities, industry and different types of experiences will be used as controls to measure the relationships and the impacts of business planning and innovation on the performance of nascent firms overtime. Results from two rounds of pre-testing informed the design of the instrument included in the main survey. The three waves of data are used to first test and compare the use of planning amongst nascent firms by their degrees of innovation and then to examine their impact on performance overtime through regression analyses. Results and Implications Three waves of data collection have been completed. Preliminary results show that on average, innovative firms are more likely to have a business plans than their low innovative counterpart. They are also most likely to update their plan suggesting a more continuous use of the plan over time than previously thought. Further analyses regarding the relationships between business planning, innovation and performance are undergoing. This paper is expected to contribute to the literature on business planning and innovation by measuring quantitatively their impact on nascent firms activities and performance at different stages of their development. In addition, this study will shed a new light on the business planning-performance relationship by disentangling plans, types of nascent firms regarding their innovation degres and their performance over time. Finally, we expect to increase the understanding of the venture creation process by analysing those questions on nascent firms from a large longitudinal sample of randomly selected ventures. We acknowledge the results from this study will be preliminary and will have to be interpreted with caution as the business planning-performance is not a straightforward relationship (Brinckmann et al., 2010). Meanwhile, we believe that this study is important to the field of entrepreneurship as it provides some much needed insights on the processes used by nascent firms during their creation and early operating stages.

The momentum effect in competitions : field evidence from tennis matches

It is often suggested that there is a psychological advantage to be leading in a competition. It is, however, hard to identify such an effect econometrically. Using a Regression Discontinuity Design over a large dataset of tennis matches (N=634,095) the present paper exploits the randomised variation in first set results that occurs when the first set is decided by a close tie break (N=72,294). I find that winning the first set has a significant and strong effect on the result of the second set. A player who wins a close first set tie break will, on average, win one game more in the second set. I discuss the likely economic and psychological explanations of this phenomenon.

Applying quality management to project delivery in Hong Kong : A field study of management perceptions

The concept of market-driven rather than product-driven quality management has been given prominence through the report of a recent inquiry into the performance of the Hong Kong construction industry. The report submitted to the Government of Hong Kong in 2001 establishes a new vision of ‘an integrated industry that is capable of continuous improvement towards excellence in the market-driven environment’. Given the current economic downturn, major contractors are facing many challenges to realize this new quality oriented vision. This paper addresses the critical and timely issue of applying quality management to the project delivery process in Hong Kong. The paper attempts to capture and critically examine management perceptions of quality management aspects as applied to a local large-scale road construction project. Based on the analysis of questionnaire feedback and face-to-face interviews, the paper reveals key attributes of a successful application of quality management approaches, and identifies a mechanism for facilitating such implementation.