Conversion and verification procedure for goal-based control programs

Fault tolerance and safety verification of control systems are essential for the success of autonomous robotic systems. A control architecture called Mission Data System, developed at the Jet Propulsion Laboratory, takes a goal-based control approach. In this paper, a method for converting goal network control programs into linear hybrid systems is developed. The linear hybrid system can then be verified for safety in the presence of failures using existing symbolic model checkers. An example task is developed and successfully verified using HyTech, a symbolic model checking software for linear hybrid systems

A Neo-Institutional Assessment of Cooperative Evolution: Comparing the Australian Wheat Board and the Fonterra Dairy Group

Agribusiness,

Helicopter cabin noise: Methods of source and path identification and characterization

Internal noise sources in a helicopter are considered. These include propulsion machinery, comprising engine and transmission, and turbulent boundary layer effects. It is shown that by using relatively simple concepts together with careful experimental work it is possible to generate reliable data on which to base the design of high performance noise control treatments

Eccentric discs in binaries with intermediate mass ratios: Superhumps in the VY Sculptoris stars

We investigate the role of the eccentric disc resonance in systems with mass ratios q greater than 1/4, and demonstrate the effects that changes in the mass flux from the secondary star have upon the disc radius and structure. The addition of material with low specific angular momentum to its outer edge restricts a disc radially. Should the mass flux from the secondary be reduced, it is possible for the disc in a system with mass ratio as large as 1/3 to expand to the 3:1 eccentric inner Lindblad resonance and for superhumps to be excited.Comment: 6 pages with 7 figures, accepted by MNRA

On Morals, Markets, and Climate Change: Exploring Pope Francis’ Challenge

The relation between Culture and Business has caught researchers’ attention long ago; itis not hard to find studies relating to these topics. According to Hofstede et al. (2010, p.18), Hampden-Turner and Trompenaars (2012, p. 8), and Erez and Gati (2004, p. 5),culture can be defined in many levels, for example, organizational culture, and national culture. The field of Business also contains several disciplines, for example, International Business Management, Project Management, and Project Governance. However, not somany studies can be found studying the relation between National Culture and Project Governance; therefore, this study is focused on this relation.This study is designed following a qualitative approach in order to clarify the relation between National Culture and Project Governance Principles. Case studies are used targeting the IT industry of three countries, Spain, Sweden, and Taiwan. These cases also contain the classical theory of cultural dimensions from Hofstede. Hofstede’s dimensionsare Power Distance (PDI), Individualism vs. Collectivism (IDV), Uncertainty Avoidance(UAI), Masculinity vs. Femininity (MAS), Long-term Orientation (LTO), and Indulgencevs. Restraint (IDU). They are applied in this study for distinguishing the differences between countries. This study is also based on the definition of Project GovernancePrinciples from Garland (2009), Klakegg (2008), and Müller et al. (2013). ProjectGovernance Principles are split into two categories as well, hard/ structural principles andsoft/ behaviour principles.In order to clarify the link between National Culture and Project Governance Principles,this thesis’ authors interviewed 19 people, including 10 project managers and 9 experts.All of them have a long experience dealing with Project Management in the three selected countries. Their answers are based on the knowledge and experience of Project Management and Project Governance, as well as their opinions about their own national culture. After analysing the interviews, the authors consider that differences between these three countries in Project Governance and Project Governance Principles do exist. On the other hand, there are also some similar parts, for example, the influence ofcustomers’ orientation and preference. Moreover, respondents, Project Managers and Experts, all mentioned it is also necessary to be aware of the globalized environment, inother words, there is no influence of a single national culture in one country anymore.However, they all admit the importance of their own national culture as well. All these findings from this study encourage further and deeper study in the future

Normal Heat Conduction in a Chain with Weak Interparticle Anharmonic Potential

We analytically study heat conduction in a chain with interparticle interaction V(x)=lambda[1-cos(x)] and harmonic on-site potential. We start with each site of the system connected to a Langevin heat bath, and investigate the case of small coupling for the interior sites in order to understand the behavior of the system with thermal reservoirs at the boundaries only. We study, in a perturbative analysis, the heat current in the steady state of the one-dimensional system with weak interparticle potential. We obtain an expression for the thermal conductivity, compare the low and high temperature regimes, and show that, as we turn off the couplings with the interior heat baths, there is a "phase transition:'' the Fourier's law holds only at high temperatures

Inhibition of ice crystallisation in highly viscous aqueous organic acid droplets

International audienceHomogeneous nucleation of ice within aqueous solution droplets and their subsequent crystallisation is thought to play a significant role in upper tropospheric ice cloud formation. It is normally assumed that homogeneous nucleation will take place at a threshold supersaturation, irrespective of the identity of the solute, and that rapid growth of ice particles will follow immediately after nucleation. However, it is shown here through laboratory experiments that droplets may not readily freeze in the very cold tropical tropopause layer (TTL, typical temperatures of 186?200 K). In these experiments ice crystal growth in citric acid solution droplets did not occur when ice nucleated below 197±6 K. Citric acid, 2-hydroxypropane-1,2,3-tricarboxyllic acid, is a molecule with similar functionality to oxygenated organic compounds which are ubiquitous to atmospheric aerosol and is therefore thought to be a sensible proxy for atmospheric organic material. Evidence is presented that suggest citric acid solution droplets become ultra-viscous or perhaps even glassy under atmospherically relevant conditions. Diffusion of liquid water molecules to ice nuclei is expected to be very slow in ultra-viscous solution droplets and this most likely provides an explanation for the experimentally observed inhibition of ice crystallisation. The implications of ultra-viscous solution droplets for ice cloud formation and supersaturations in the TTL are discussed

Stratigraphical evidence of Elysium sea ice from HiRise images

Abstract not available