A study on passive cooling in subsea power electronics

This paper proposes a simplified approach to model the thermal behavior of the insulated gate bipolar transistors (IGBTs) in a subsea power electronic converter. The models are based on empirical relations for natural convection in water, and IGBT datasheet values. The proposed model can be used in the design of subsea converters and in the...

Analytical Field and Torque Analysis of a Reaction Sphere

In recent years, the increasing need in small satellite solutions triggers the miniaturization of attitude control systems. Reaction spheres were proposed as promising replacements of conventional reaction wheels for their 4π rotations. Since the generated control torques could be about any desired axes, a single reaction sphere is sufficient...

A columnar architecture for modern risk management systems

3D digital city models form the basis for flow simulations (e.g. wind flow and water runoff), urban planning, underand over- ground formation analysis, and they are very important for automated anomaly detection on man made structures. They consist of large collections of semantically rich objects which have many properties such as material and...

BitTorrent's Dilemma: Enhancing Reciprocity or Reducing Inequity

Enhancing reciprocity has been one of the primary motivations for the design of incentive policies in BitTorrent-like P2P systems. Reciprocity implies that peers need to contribute their bandwidth to other peers if they want to receive bandwidth in return. However, the over-provisioning that characterizes today’s BitTorrent communities and the...

Fast Download but Eternal Seeding: The Reward and Punishment of Sharing Ratio Enforcement

Many private BitTorrent communities employ Sharing Ratio Enforcement (SRE) schemes to incentivize users to contribute their upload resources. It has been demonstrated that communities that use SRE are greatly oversupplied, i.e., they have much higher seeder-to-leecher ratios than communities in which SRE is not employed. The first order effect...