Second year technical report on-board processing for future satellite communications systems

Advanced baseband and microwave switching techniques for large domestic communications satellites operating in the 30/20 GHz frequency bands are discussed. The nominal baseband processor throughput is one million packets per second (1.6 Gb/s) from one thousand T1 carrier rate customer premises terminals. A frequency reuse factor of sixteen is assumed by using 16 spot antenna beams with the same 100 MHz bandwidth per beam and a modulation with a one b/s per Hz bandwidth efficiency. Eight of the beams are fixed on major metropolitan areas and eight are scanning beams which periodically cover the remainder of the U.S. under dynamic control. User signals are regenerated (demodulated/remodulated) and message packages are reformatted on board. Frequency division multiple access and time division multiplex are employed on the uplinks and downlinks, respectively, for terminals within the coverage area and dwell interval of a scanning beam. Link establishment and packet routing protocols are defined. Also described is a detailed design of a separate 100 x 100 microwave switch capable of handling nonregenerated signals occupying the remaining 2.4 GHz bandwidth with 60 dB of isolation, at an estimated weight and power consumption of approximately 400 kg and 100 W, respectively

The Adoption and Enforcement of a Technological Regime: The Case of the first IT Regime

In this paper we explore the process of adoption and enforcement of a number of new information processing technologies, such as the typewriter, calculators, tabulation gears and book-keeping machines, starting from the 1880s in the United States. We show that their innovation and diffusion was inexorably coupled to the economic development in the USA in the late 19th century. It is a complex and contradictory consequence of underlying socio-economic processes that led to the formation of modern organisational structures in large scale manufacturing which required systematic and efficient information processing. The typewriter and all the complementary office automation devices that entered the scene shortly after were part of a socio-technical regime that started being established: the office work regime or as we prefer to call it the first IT regime, as for the first time a technology was set up to process information on large scale. The logic of large scale manufacturing to produce standardised products in large series and to apply labour saving techniques was cast into the organisation of administration. This required a convergence of technical practices. The lock-in to the inferior QWERTY-keyboard is hence the outcome of the diffusion and hardening of the First IT Regime.Technological regimes; adaption and enforcement of technologies; information technology; QWERTY

Technology, Wages and Skill Shortages: Evidence from UK Micro Data

Why have skill shortages continue to persist despite increases in training and the skill levels of the workforce? We argue that technical progress has raised the demand for skilled labour to mach the observed increase in supply. We provide econometric evidence in support of this hypothesis, showing that skill shortages are higher for establishments that use advanced technology in the production process. We also provide econometric evidence that hiring difficulties are inversely related to the relative wage, as theory would suggest. Our results have clear implications for policy. If technological progress continues to be skill biased, policies that address skills deficiencies will only be successful if they produce a continual, rather than a temporary, increase in levels of skills among the workforc

Mesmerizer: A Effective Tool for a Complete Peer-to-Peer Software Development Life-cycle

In this paper we present what are, in our experience, the best practices in Peer-To-Peer(P2P) application development and how we combined them in a middleware platform called Mesmerizer. We explain how simulation is an integral part of the development process and not just an assessment tool. We then present our component-based event-driven framework for P2P application development, which can be used to execute multiple instances of the same application in a strictly controlled manner over an emulated network layer for simulation/testing, or a single application in a concurrent environment for deployment purpose. We highlight modeling aspects that are of critical importance for designing and testing P2P applications, e.g. the emulation of Network Address Translation and bandwidth dynamics. We show how our simulator scales when emulating low-level bandwidth characteristics of thousands of concurrent peers while preserving a good degree of accuracy compared to a packet-level simulator

FPGA based remote code integrity verification of programs in distributed embedded systems

The explosive growth of networked embedded systems has made ubiquitous and pervasive computing a reality. However, there are still a number of new challenges to its widespread adoption that include scalability, availability, and, especially, security of software. Among the different challenges in software security, the problem of remote-code integrity verification is still waiting for efficient solutions. This paper proposes the use of reconfigurable computing to build a consistent architecture for generation of attestations (proofs) of code integrity for an executing program as well as to deliver them to the designated verification entity. Remote dynamic update of reconfigurable devices is also exploited to increase the complexity of mounting attacks in a real-word environment. The proposed solution perfectly fits embedded devices that are nowadays commonly equipped with reconfigurable hardware components that are exploited to solve different computational problems