Flock inspired area coverage using wireless boid-like sensor agents

Simulated flocking is achievable using three boid rules [13]. We propose an area coverage model inspired by Reynolds’ flocking algorithm, investigating strategies for achieving quality coverage using flocking rules. Our agents are identical and autonomous, using only local sensory information for indirect communication. Upon deployment, agents are in the default separation mode. The cohesion rule would then guarantee that agents remain within the swarm, covering spaces with explored neighbour spaces. Four experiments are conducted to evaluate our model in terms of coverage quality achieved. We firstly investigate agents’ separation speed before the speed with which isolated agents re-organizes is investigated. The third experiment compares coverage quality achieved using our model with coverage quality achieved using random guessing. Finally, we investigate fault tolerance in the event of agents’ failures. Our model exhibits good separation and cohesion speed, achieving high quality coverage. Additionally, the model is fault tolerant and adaptive to agents’ failures.

Special issue : securing distributed networks and systems

With decades of progress toward ubiquitous networks and systems, distributed computing systems have played an increasingly important role in the industry and society. However, not many distributed networks and systems are secure and reliable in the sense of defending against different attacks and tolerating failures automatically, thus guaranteeing properties such as performance, and offering security against intentional threats. This special issue focuses on securing distributed networks and systems.

Software reliability growth models based on local polynomial modeling with kernel smoothing

Software reliability growth models (SRGMs) are extensively employed in software engineering to assess the reliability of software before their release for operational use. These models are usually parametric functions obtained by statistically fitting parametric curves, using Maximum Likelihood estimation or Least–squared method, to the plots of the cumulative number of failures observed N(t) against a period of systematic testing time t. Since the 1970s, a very large number of SRGMs have been proposed in the reliability and software engineering literature and these are often very complex, reflecting the involved testing regime that often took place during the software development process. In this paper we extend some of our previous work by adopting a nonparametric approach to SRGM modeling based on local polynomial modeling with kernel smoothing. These models require very few assumptions, thereby facilitating the estimation process and also rendering them more relevant under a wide variety of situations. Finally, we provide numerical examples where these models will be evaluated and compared.

Multiple actuator fault tolerance for static nonlinear systems based on minimum velocity jump

Static nonlinear systems are common when the model of the kinematics of mechanical or civil structures is analyzed for instance kinematics of robotic manipulators. This paper addresses the maximum effort toward fault tolerance for any number of the locked actuators failures in static nonlinear systems. It optimally reconfigures the inputs via a mapping that maximally accommodates the failures. The mapping maps the failures to an extra action of healthy actuators that results to a minimum jump for the velocity of the output variables. Then from this mapping, the minimum jump of the velocity of the output is calculated. The conditions for a zero velocity jump of the output variables are discussed. This shows that, when the conditions of fault tolerance are maintained, the proposed framework is capable of fault recovery not only at fault instances but also at the whole output trajectory. The proposed mapping is validated by three case studies.

Optimal fault tolerant Jacobian matrix generators for redundant manipulators

The design of locally optimal fault-tolerant manipulators has been previously addressed via adding constraints on the bases of a desired null space to the design constraints of the manipulators. Then by algebraic or numeric solution of the design equations, the optimal Jacobian matrix is obtained. In this study, an optimal fault-tolerant Jacobian matrix generator is introduced from geometric properties instead of the null space properties. The proposed generator provides equally fault-tolerant Jacobian matrices in R3 that are optimally fault tolerant for one or two locked joint failures. It is shown that the proposed optimal Jacobian matrices are directly obtained via regular pyramids. The geometric approach and zonotopes are used as a novel tool for determining relative manipulability in the context of fault-tolerant robotics and for bringing geometric insight into the design of optimal fault-tolerant manipulators.

Jillong 2030 : mistakes, challenges & urban visions

Geelong has long been a second cousin to Melbourne economically and in development. Whilst historically wishing to capture the role as administrative capital of the new colony of Victoria, it missed out due to the entrepreneurism of Melbourne. Despite this, it embraced contemporary industrialism, particularly automotive, and built upon its port and wool export capacities. Politics, intransigence and lack of economic investment compounded the failure to create quality urban fabric and enable innovative planning. The last 50 years have witnessed attempts to re-chart a robust and co-ordinated urban framework and vision, aided by the former Geelong Regional Commission (GRC) and more recently the amalgamated City of Greater Geelong (CGG), resulting in varying successes and several failures. Urban design has repeatedly, and historically, surfaced as the catalyst for creative and successful growth in Geelong, or Jillong at the Wathaurong described the place. This paper considers the planning, urban design and environmental legacy of Geelong. It critiques its successes and failures, drawing out the salient issues and themes that underpin its opportunities and quality place-making adventures, and considers the key challenges it now faces. Importantly, it sets forth the six planning and design challenges it must confront in the next 10 years to create a robust, creative, healthy and environmentally liveable place, of which urban design regeneration surfaces as a core need, or the city will continue along its haphazard pathway without cohesion and purpose.

Iraq and the Arab revolutions : protesting the failure to democratise governance

As the Arab Revolutions swept across the Middle East and North Africa in late 2010 and into 2011, Iraqis were confronted with the failures of their own democracy to deliver on the many promises made to them since 2003. This led to weeks of scattered protests across Iraq, culminating in the “Day of Rage” (February 25, 2011) in which thousands of protestors took to the streets in at least 17 separate demonstrations across the country following Friday prayers. On the surface, these protests shared much in common with others across the region: the use of Facebook and other social media to promote the protests, and the focus on corruption, unemployment and poor public infrastructure. Also similar was the reaction of key Iraqi political figures such as Maliki and Barzani who met Iraqi protests with a mixture of brutal suppression and modest political and economic concessions. However, as this paper will demonstrate, upon closer inspection the Iraqi protests are in fact very different to others across the MENA and are therefore among the most significant for the future of democracy in the region. The Iraqi people were not protesting against an autocratic regime or an entrenched monarchy that had held power for decades, but a relatively new – and supposedly ‘democratic’ - political elite who had been brought to power in the wake of the US invasion. Indeed, while protestors across the region called for more democracy in the form of a written constitution, free and fair elections, a robust media sphere and the rule of law, Iraqis were protesting against the failures of the Iraqi government to democratise such mechanisms of governance (all of which they more or less have). They felt routinely disenfranchised by a state that has manipulated the very institutions and discourses of democracy to retain, rather than diffuse, power.

Optimal fault-tolerant robotic manipulators

This thesis addresses “Optimal Fault-Tolerant Robotic Manipulators” for locked-joint failures and consists of three components. It begins by investigating the regions of workspace where the manipulator can operate with high reliability. It then continues with an efficient deployment of kinematic redundancies for fault-tolerant operation. Finally, it presents a novel method for design of optimal fault-tolerant manipulators.

An approach to faulty reader detection in RFID reader network

Radio Frequency Identification (RFID) technology is becoming increasingly popular as an automated tool for object monitoring and identification in a cost-efficient manner. RFID systems are made up of heterogeneous components consisting of both hardware and software. RFID components such as the readers are prone to failures with serious consequences to the overall system. Thus, issues such as reliability and dependability of RFID systems are receiving attention recently. This mandates fault management that includes monitoring the health of RFID readers and accessing the RFID reader configurations remotely. Therefore, an approach that detects the faulty readers with the aim to minimize the impacts of the faulty readers on the system reliability and dependability is of paramount importance. In this chapter, the authors discuss an approach to detect faulty readers in networked RFID system environments. Performance evaluation of the approach against other techniques is presented and shows that it performs reasonably well in the presence of faulty readers.

Quality control of sensor network data

A wireless sensor network (WSN) is a group of sensors that are geographically distributed and interconnected by wireless networks. Sensors gather information about the state of physical world. Then, after processing forward them to the main destination. To be able to provide this service, there are many aspects of communication techniques that need to be explored. Supporting quality of service (QoS) will be of critical importance for pervasive WSNs that serve as the network infrastructure of diverse applications. To illustrate new research and development interests in this field, this paper examines and discusses the requirements, critical challenges, and open research issues on QoS management in WSNs. A brief overview of recent progress is given.

Well-conditioned configurations of fault-tolerant manipulators

Fault-tolerant motion of redundant manipulators can be obtained by joint velocity reconfiguration. For fault-tolerant manipulators, it is beneficial to determine the configurations that can tolerate the locked-joint failures with a minimum relative joint velocity jump, because the manipulator can rapidly reconfigure itself to tolerate the fault. This paper uses the properties of the condition numbers to introduce those optimal configurations for serial manipulators. The relationship between the manipulator's locked-joint failures and the condition number of the Jacobian matrix is indicated by using a matrix perturbation methodology. Then, it is observed that the condition number provides an upper bound of the required relative joint velocity change for recovering the faults which leads to define the optimal fault-tolerant configuration from the minimization of the condition number. The optimization problem to obtain the minimum condition number is converted to three standard Eigen value optimization problems. A solution is for selected optimization problem is presented. Finally, in order to obtain the optimal fault-tolerant configuration, the proposed method is applied to a 4-DoF planar manipulator.

Authoritarian deliberation : the deliberative turn in Chinese political development

Authoritarian rule in China is now permeated by a wide variety of deliberative practices. These practices combine authoritarian concentrations of power with deliberative influence, producing the apparent anomaly of authoritarian deliberation. Although deliberation is usually associated with democracy, they are distinct phenomena.Democracy involves the inclusion of individuals in matters that affect them through distributions of empowerments such as votes and rights. Deliberation is a mode of communication involving persuasion-based influence. Combinations of non-inclusive power and deliberative influence—authoritarian deliberation— are readily identifiable in China, probably reflecting failures of command authoritarianism under the conditions of complexity and pluralism produced by market-oriented development. The concept of authoritarian deliberation frames two possible trajectories of political development in China: the increasing use of deliberative practices stabilizes and strengthens authoritarian rule, or deliberative practices serve as a leading edge of democratization.

Exploring potential success factors for procurement of privately financed infrastructure

Australia has joined many governments to adopt public-private partnership (PPP) as a major strategy for procuring infrastructure for decades. However, failures have occurred although the market has been considered to be a mature and sophisticated one. Failures have typically been traced back to inappropriate economic evaluation and a lack of value-for-money. In particular, a literature review has identified that there was no holistic consideration on the evaluation of procurement transactions of PPP projects. The transaction costs of PPPs were not handled properly. In this paper, theories of transaction cost economics are proposed for the purpose of such a holistic institutional economic evaluation. These theories are analysed in order to identify potential critical success factors for a strategic infrastructure procurement framework. The potential critical success factors are identified and grouped into a number of categories that match the theories of transaction cost economics. These categories include (1) Asset Specificity, (2) Organizational Capability, (3) Transaction Frequency, (4) Behavioural Uncertainty, and (5) Environmental Uncertainty. These potential critical success factors may be subject to an empirical test in the future. The proposed framework will offer decision makers with an insight into project life cycle economic outcomes needed to successfully deliver PPPs.

Optimising errors in signaling corporate collapse using MCCCRA

Purpose – The purpose of this paper is to put forward an innovative approach for reducing the variation between Type I and Type II errors in the context of ratio-based modeling of corporate collapse, without compromising the accuracy of the predictive model. Its contribution to the literature lies in resolving the problematic trade-off between predictive accuracy and variations between the two types of errors.

Design/methodology/approach – The methodological approach in this paper – called MCCCRA – utilizes a novel multi-classification matrix based on a combination of correlation and regression analysis, with the former being subject to optimisation criteria. In order to ascertain its accuracy in signaling collapse, MCCCRA is empirically tested against multiple discriminant analysis (MDA).

Findings – Based on a data sample of 899 US publicly listed companies, the empirical results indicate that in addition to a high level of accuracy in signaling collapse, MCCCRA generates lower variability between Type I and Type II errors when compared to MDA.

Originality/value – Although correlation and regression analysis are long-standing statistical tools, the optimisation constraints that are applied to the correlations are unique. Moreover, the multi-classification matrix is a first in signaling collapse. By providing economic insight into more stable financial modeling, these innovations make an original contribution to the literature.