Classical and Quantum Equations of Motion of an n-dimesional BTZ Black Hole

We investigate the gravitational collapse of a non-rotating $n$-dimensional BTZ black hole in AdS space in the context of both classical and quantum mechanics. This is done by first deriving the conserved mass of a "spherically" symmetric domain wall, which is taken as the classical Hamiltonian of the black hole. Upon deriving the conserved mass, we also point out that, for a "spherically" symmetric shell, there is an easy and straight-forward way of determining the conserved mass, which is related to the proper time derivative of the interior and exterior times. This method for determining the conserved mass is generic to any situation (i.e. any equation of state), since it only depends on the energy per unit area, $\sigma$, of the shell. Classically, we show that the time taken for gravitational collapse follows that of the typical formation of a black hole via gravitational collapse, that is, an asymptotic observer will see that the collapse takes an infinite amount of time to occur, while an infalling observer will see the collapse to both the horizon and the classical singularity occur in a finite amount of time. Quantum mechanically, we take primary interest in the behavior of the collapse near the horizon and near the classical singularity from the point of view of both asymptotic and infalling observers. In the absence of radiation and fluctuations of the metric, quantum effects near the horizon do not change the classical conclusions for an asymptotic observer. The most interesting quantum mechanical effect comes in when investigating near the classical singularity. Here, we find, that the quantum effects in this region are able to remove the classical singularity at the origin, since the wave function is non-singular, and is also displays non-local effects, which depend on the energy density of the domain wall.Comment: 10 pages. arXiv admin note: text overlap with arXiv:0912.186

Dynamic Replanning of Low Noise Rotorcraft Operations

A new method for rapidly planning and dynamically replanning low noise rotorcraft flight operations is developed. A large database of rotorcraft maneuver segments is generated, and an acoustic cost is assigned to each segment by using a computationally efficient semiempirical rotorcraft noise modeling method that accurately models the changes in rotor noise caused by maneuvering flight. Combinatoric optimization techniques are then employed to combine these maneuver segments into a low noise optimal flight path. A simple heuristic for estimating the total acoustic cost required to reach the target location is developed and incorporated into the search algorithm, allowing the computation of low noise paths in seconds. A procedure for implementing an anytime version of the method is described, enabling feasible solutions to be dynamically replanned on the flyi.e., in fractions of a secondand refined over time to a low noise optimal solution

Hard, soft or lean? Planning on medium size construction projects

In a paper presented to the 11th Annual ARCOM Conference, Johansen examined the way that managers and planners in medium sized construction projects plan in a flexible manner. This was termed "soft planning" and contrasted with the textbook approach which was termed "hard" planning. The fundamental components of hard planning are firm dates and critical activities. The reality was found to be quite different from the textbook approach. (Johansen, 1996a) The conclusion then, was that methods of soft planning methodologies should be developed to support what was actually happening. Here this conclusion is revised in the light of lean production concepts. After defining these concepts, the authors consider how they can affect the development of planning theories in construction; in particular, how concepts such as “shielding”, “lookahead planning” and “last planner” can allow managers to overcome the barriers to hard planning

Implementing lean: UK culture and systems change

For the IGLC 12 Conference the authors reported the results of implementing Last PlannerTM methods with a large UK contracting company. The projects studied demonstrated some success but also some cultural, organizational and systemic barriers to its effective implementation. Alarcon and Conte’s White Paper for the IGLC11 conference discussed these issues and invited researchers to consider them. In response, the authors have reflected upon and critically re-analysed the research as a means to refocus their future work in implementing Lean Construction methods in UK construction. Based on a review of the literature on construction culture we have identified theoretical factors that, together with Alarcon and Conte's list of critical organizational elements, provide a framework against which the results of the research have been considered. We conclude that the implementation of Last Planner was hindered by not fully considering cultural, organizational and systemic problems and by failing to recognize how deepseated these problems could be. We intend, in future projects, to take a more considered, and wider approach to Lean Construction (possibly using the LCI’s Lean Project Delivery System) and to focus our attention upon construction ventures where efforts at culture change have already started - in particular, where strategic partnering arrangements are in place

The lack of design quality focus in construction: a case for examining suitable design processes

A large number of projects in UK construction now involve contractor-led design and are thus very different from the traditional approach which formed the basis of the original Royal Institute of British Architects (RIBA) Outline Plan of Work. Such integrated and contractor-led approaches support the reform agenda of the late 1990s that was introduced to tackle process inefficiency. However, within the design professions there has been concern that this resulted in buildings that were designed-down to a cost rather than designed-up to a value. An attempt to address this resulted in the formation of the Commission for Architecture and Built Environment (CABE) in 1999 and the launch, in 2003, of the Design Quality Indicator (DQI) which measures how well a building satisfies stakeholders. This paper presents the early phases of doctoral research which will examine the impact of integrated design management approaches upon Design Quality

Time dependent fluctuations and particle production in cosmological de Sitter and anti-de Sitter spaces

We study the evolution of time-dependent fluctuations and particle production in an expanding dS and contracting AdS universe. Using the functional Schrodinger formalism we are able to probe the time dependent regime which is out of the reach of the standard approximations like the Bogolyubov method. In both cases, the evolution of fluctuations is governed by the harmonic oscillator equation with time dependent frequency. In the case of an expanding dS universe we explicitly show that the frequency of fluctuations produced at a certain moment diminish in time, while the distribution of the created particles quickly approaches the thermal radiation of the dS space. In the case of a contracting AdS universe we show that the frequency of fluctuations produced at a certain moment grow in time. Nominally, the temperature of radiation diverges as the Big Crunch is approaching, however, increasing oscillations of the spectrum make the temperature poorly defined, which is in agreement with the fact that AdS space does not have an event horizon which would cause thermal radiation. Unlimited growth of fluctuations indicates that an eventual tunneling into AdS vacuum would have catastrophic consequences for our universe.Comment: 8 pages, 6 figure