this paper investigates the multi-band ofdm (mb-ofdm) based physical (phy) layer proposal for ieee 802.15.3a working group on short-range high data-rate ultra-wide-band (uwb) communications. an overview of the mb-ofdm phy layer architecture with its various parameters is presented and the optimal choice of critical parameters is discussed. next, we derive the theoretical un-coded bit error rate...

Collaborative Virtual Environments are virtual reality spaces that enable participants to collaborate and share objects as if physically present in the same place. These collaboration spaces require strict performance characteristics. Today there are many systems developed specifically for collaboration, including DIVE, CALVIN, and COVEN. At the same time, some relatively new standards that add...

Orthogonal frequency division multiplexing (OFDM) system is widely used wireless communication system in recent years. The major drawback of OFDM system is high Peak-to Average Power Ratio (PAPR). To reduce the PAPR of OFDM system different PAPR reduction techniques have been proposed. In this paper, we are evaluating the performance of different non-linear companding techniques.

In this paper we describe oPASS (Optical PAcket Switch Simulator), a simulation tool specifically designed for the evaluation of slotted Optical Packet Switching (OPS) switching architectures. oPASS is implemented in OMNET++, a general purpose eventdriven simulation framework. oPASS allows the evaluation of classical parameters in packet networks like packet loss probability and distribution of...

Applications with varying array access patterns in a parallel distributed memory machine require to dynamically change array mappings. Hpf (High Performance Fortran) provides such remappings, possibly on partially replicated data, explicitly through the realign and redistribute directives and implicitly at procedure calls and returns. However such features are left out of the hpf subset or of t...

with regard to the society’s need for complicated software and high level of expenses on its development, it is necessary to take all stakeholders’ requirements and the demands into consideration, before any investments and put on the design and utilization stages. software architecture is a technical description of a software system that indicates components and their relationships between the...

RWAPI is a low-level communication interface designed for clusters of PCs. It has been developed to provide performance to higher applications on a wide variety of architectures. We implemented RWAPI on top of the modular software architecture called GRWA. RWAPI supports Ethernet, InfiniBand and Myrinet network interconnects. This paper introduces RWAPI and the design of its network component o...

When developing large software systems it is hard to predict their performance behavior at early development stages. This paper presents an engineering methodology for performance prediction based on high-level application architectures that are simulated within the real infrastructure setup. This methodology is realized in a performance simulation framework. Our results show that a software sy...