Hydrocarbon field size distributions: a case study in mixed integer nonlinear programming

Of key importance to oil and gas companies is the size distribution of fields in the areas that they are drilling. Recent arguments suggest that there are many more fields yet to be discovered in mature provinces than had previously been thought because the underlying distribution is monotonic not peaked. According to this view the peaked nature of the distribution for discovered fields reflects not the underlying distribution but the effect of economic truncation. This paper contributes to the discussion by analysing up-to-date exploration and discovery data for two mature provinces using the discovery-process model, based on sampling without replacement and implicitly including economic truncation effects. The maximum likelihood estimation involved generates a high-dimensional mixed-integer nonlinear optimization problem. A highly efficient solution strategy is tested, exploiting the separable structure and handling the integer constraints by treating the problem as a masked allocation problem in dynamic programming.

Traffic policing in ATM networks with multimedia traffic: the super leaky bucket

Traffic policing and bandwidth management strategies at the User Network Interface (UNI) of an ATM network are investigated by simulation. The network is assumed to transport real time (RT) traffic like voice and video as well as non-real time (non-RT) data traffic. The proposed policing function, called the super leaky bucket (S-LB), is based on the leaky bucket (LB), but handles the three types of traffic differently according to their quality of service (QoS) requirements. Separate queues are maintained for RT and non-RT traffic. They are normally served alternately, but if the number of RT cells exceeds a threshold, it gets non-pre-emptive priority. Further increase of the RT queue causes low priority cells to be discarded. Non-RT cells are buffered and the sources are throttled back during periods of congestion. The simulations clearly demonstrate the advantages of the proposed strategy in providing improved levels of service (delay, jitter and loss) for all types of traffic.

Three parallel programming paradigms: Comparisons on an archetypal PDE computation

Three paradigms for distributed-memory parallel computation that free the application programmer from the details of message passing are compared for an archetypal structured scientific computation -- a nonlinear, structured-grid partial differential equation boundary value problem -- using the same algorithm on the same hardware. All of the paradigms -- parallel languages represented by the Portland Group's HPF, (semi-)automated serial-to-parallel source-to-source translation represented by CAP-Tools from the University of Greenwich, and parallel libraries represented by Argonne's PETSc -- are found to be easy to use for this problem class, and all are reasonably effective in exploiting concurrency after a short learning curve. The level of involvement required by the application programmer under any paradigm includes specification of the data partitioning, corresponding to a geometrically simple decomposition of the domain of the PDE. Programming in SPMD style for the PETSc library requires writing only the routines that discretize the PDE and its Jacobian, managing subdomain-to-processor mappings (affine global-to-local index mappings), and interfacing to library solver routines. Programming for HPF requires a complete sequential implementation of the same algorithm as a starting point, introduction of concurrency through subdomain blocking (a task similar to the index mapping), and modest experimentation with rewriting loops to elucidate to the compiler the latent concurrency. Programming with CAPTools involves feeding the same sequential implementation to the CAPTools interactive parallelization system, and guiding the source-to-source code transformation by responding to various queries about quantities knowable only at runtime. Results representative of "the state of the practice" for a scaled sequence of structured grid problems are given on three of the most important contemporary high-performance platforms: the IBM SP, the SGI Origin 2000, and the CRAYY T3E.

Issues in delivering multimedia content to mobile devices

The scalability of a computer system is its response to growth. It is also depended on its hardware, its operating system and the applications it is running. Most distributed systems technology today still depends on bus-based shared memory which do not scale well, and systems based on the grid or hypercube scheme requires significantly less connections than a full inter-connection that would exhibit a quadratic growth rate. The rapid convergence of mobile communication, digital broadcasting and network infrastructures calls for rich multimedia content that is adaptive and responsive to the needs of individuals, businesses and the public organisations. This paper will discuss the emergence of mobile Multimedia systems and provides an overview of the issues regarding design and delivery of multimedia content to mobile devices.

Innovations in learning and teaching approaches using game technologies - can "The Movies" teach how to make a movie?

The use of games technology in education is not a new phenomenon. Even back in the days of 286 processors, PCs were used in some schools along with (what looks like now) primitive simulation software to teach a range of different skills and techniques – from basic programming using Logo (the turtle style car with a pen at the back that could be used to draw on the floor – always a good way of attracting the attention of school kids!) up to quite sophisticated replications of physical problems, such as working out the trajectory of a missile to blow up an enemies’ tank. So why are games not more widely used in education (especially in FE and HE)? Can they help to support learners even at this advanced stage in their education? We aim to provide in this article an overview of the use of game technologies in education (almost as a small literature review for interested parties) and then go more in depth into one particular example we aim to introduce from this coming academic year (Sept. 2006) to help with teaching and assessment of one area of our Multimedia curriculum. Of course, we will not be able to fully provide the reader with data on how successful this is but we will be running a blog (http://themoviesineducation.blogspot.com/) to keep interested parties up to date with the progress of the project and to hopefully help others to set up similar solutions themselves. We will also only consider a small element of the implementation here and cover how the use of such assessment processes could be used in a broader context. The use of a game to aid learning and improve achievement is suggested because traditional methods of engagement are currently failing on some levels. By this it is meant that various parts of the production process we normally cover in our Multimedia degree are becoming difficult to monitor and continually assess.