Oι ομιλίες δίνονται στην Αίθουσα Δ' του Tμήματος Πληροφορικής & Tηλεπικοινωνιών (εκτός τυχόν εξαιρέσεων).

Πα 23 Mαϊου, 1.00 μμ
Καθηγ. AλκιβιάδηςAκρίτας (Πανεπιστήμιο Θεσσαλίας)
Wavelet Transforms and Data Compression (with Mathematica)

Wavelet Transforms trace their origin both in Signal Processiong and Theoretical Mathematics. Since their introduction they have found applications in many areas--most notably by the FBI, where they are used to compress fingerprint data before storing it. We present an introduction to these transforms and their application, and demonstrate the main ideas with a picture of Pedro.
 

Πα 9 Mαϊου, 1.00 μμ.
Aναπλ. Καθ. Aνδρέας Σταθόπουλος (College of William and Mary)
Application-level resource management in sequential and parallel scientific codes

Many research groups rely increasingly on medium or even small size clusters of workstations to perform scientific or engineering computations. These clusters usually involve networks with much higher overheads than traditional MPPs and they are often multiprogrammed. With the emergence of Grid computing older clusters are often not retired but incorporated in the computational environment. Relying on a batch scheduler or the operating system to manage these resources provides always suboptimal solutions.

We explore three different ways that a scientific computing code can manage these resources itself: multigrain parallelism, application-level load balancing, and application-level memory management to avoid thrashing. The first two techniques apply on iterative methods (linear systems and eigenvalue problems), while our application level memory management scheme is more general. Because the application has the ultimate knowledge of its requirements, it can vastly outperform system based solutions.