Harmonic sections in sphere bundles, normal neighborhoods of reduction loci, and instanton moduli spaces on definite 4-manifolds

We prove an existence theorem for gauge invariant $L^2$-normal neighborhoods of the reduction loci in the space ${\cal A}_a(E)$ of oriented connections on a fixed Hermitian 2-bundle $E$. We use this to obtain results on the topology of the moduli space ${\cal B}_a(E)$ of (non-necessarily irreducible) oriented connections, and to study the Donaldson $\mu$-classes globally around the reduction loci. In this part of the article we use essentially the concept of harmonic section in a sphere bundle with respect to an Euclidean connection. Second, we concentrate on moduli spaces of instantons on definite 4-manifolds with arbitrary first Betti number. We prove strong generic regularity results which imply (for bundles with "odd" first Chern class) the existence of a connected, dense open set of "good" metrics for which all the reductions in the Uhlenbeck compactification of the moduli space are simultaneously regular. These results can be used to define new Donaldson type invariants for definite 4-manifolds. The idea behind this construction is to notice that, for a good metric $g$, the geometry of the instanton moduli spaces around the reduction loci is always the same, independently of the choice of $g$. The connectedness of the space of good metrics is important, in order to prove that no wall-crossing phenomena (jumps of invariants) occur. Moreover, we notice that, for low instanton numbers, the corresponding moduli spaces are a priori compact and contain no reductions at all so, in these cases, the existence of well-defined Donaldson type invariants is obvious. The natural question is to decide whether these new Donaldson type invariants yield essentially new differential topological information on the base manifold have, or have a purely topological nature.Comment: LaTeX, 45 page

Position Estimating in Peer-to-Peer Networks

We present two algorithms for indoor positioning estimation in peer-to-peer networks. The setup is a network of two types of devices: reference devices with a known location and blindfolded devices that can determine distances to reference devices and each other. From this information the blindfolded devices try to estimate their positions. A typical scenario is navigation inside a shopping mall where devices in the parking lot can make contact with GPS satellites, whereas devices inside the building make contact with each other, devices on the parking lot, and devices fixed to the building. The devices can measure their in-between distances, with some measurement error, and exchange positioning information. However, other devices might only know their position with some error

Comparison of legislation on the safe utilisation of explosives and its application in some European mines

Blasting operations form a central part of any hard rock metal mining operation and are, given its inherent hazards, critical in ensuring safe mine working environments. In order to improve workplace safety in such operations, it is important to select the right explosives and technologies, to issue rules and procedures and to offer adequate training. Because multinational mining companies work under different jurisdictions, they have to comply with different rules with different regulators. Given that the aim is to have no Lost Time Injuries (LTI’s) at any operation within New Boliden, it is important to develop working practices that both comply with various legal requirements, are practically usable and lead to a safe working environment. The aim of the research is therefore to identify applicable legal requirements, technologies and working methods, in order to see if different working practices are compliant with these legal requirements, and whether these requirements and practices can help to meet the requirements of different regulators and Boliden’s mission objectives. This research has identified the legal requirements applying to mining operations in Sweden, Finland and Ireland, and compared working practices in several mines, operated by Boliden Mineral AB in these countries. With a comparable number of relevant legal sources, the legal structure on explosives safety requirements is generally similar. However, Nordic legislation puts more generic responsibilities on the employer, whereas Irish regulations are more specific. Blasting requirements in Finland and Sweden are mostly similar and apply to underground and surface mining operations and civil engineering, whereas Irish legislation is tailored specifically to underground mining operations. Significant differences can be seen when comparing explosives handling, in particular explosives storage, Ireland has a very different approach in this respect. Technologies influencing the explosives handling and blasting safety performance are considered to be the initiation systems used, the reliability of explosives and successful implementation of a digital track&trace system. No events leading to human injury have occurred following the utilisation of explosive materials in Boliden Mines in the past ten years. Using both Boliden and international data, it was found that the main types of explosives- and blasting related incidents are misfires, flyrock, toxic fumes and early detonation. Fault Tree Analysis, adapted forms of reliability modelling and the bow-tie method have been used to identify critical parts of the explosives handling and blasting process. Critical activities are these surrounding evacuation of the blasting area, material failures and explosives materials being unguarded. Most incidents appear to be caused by failures in communication between different departments and insufficient awareness of safety procedures. Considering that there is overlap between the various operations in terms of legal requirements and practices, it is judged to be useful to more closely align these practices, since learning from each other’s practices might improve safety levels. Also, alignment of track&trace systems, and the adoption of electronic initiation systems are recommended. It is deemed less useful to align more national requirements and practices, such as permitting and licensing procedures. In order to exchange best practices, company-wide safety guidelines and reporting based on a clear distinction of responsibilities per activity are recommended. The main conclusion is that alignment of existing safety practices and technology use is achievable given the various legal and operational constraints and is expected to ensure a zero-LTI explosives handling and blasting safety performance