Abstract
The computational efficiency of linear ?-calculi with iterators is evaluated using closed reduction strategies. The interaction between linearity and closed reduction and the computational power of linear systems with and without closed reduction is analyzed. A linear version of Gödel's System T with closed reductions is defined to analyze the computational power of linear systems. Closed reduction strategies in the ?-calculus restrict the reduction rules since closed reduction strategies can take place when certain terms are closed and do not contain free variables. Closed reduction strategies impose strong constraints on the application of reduction rules. Closed reduction strategies can simulate call-by-name and call-by-value evaluations in the ?-calculus. Linear ?-calculus with iterators can be efficiently analyzed by relaxing the constraints on the construction of iterator terms.

Abstract
System L is a linear A-calculus with numbers and an iterator, which, although imposing linearity restrictions on terms, has all the computational power of Godel's System T. System C owes its power to two features: the use of a closed reduction strategy (which permits the construction of an iterator on an open function, but only iterates the function after it becomes closed), and the use of a liberal typing rule for iterators based on iterative types. In this paper, we study these new types, and show how they relate to intersection types. We also give a sound and complete type reconstruction algorithm for System L.

Abstract
With the recent trend of analysing the process of computation through the linear logic looking glass, it is well understood that the ability to copy and erase data is essential in order to obtain a Turing-complete computation model. However, erasing and copying don't need to be explicitly included in Turing-complete computation models: in this paper we show that the class of partial recursive functions that are syntactically linear (that is, partial recursive functions where no argument is erased or copied) is Turing-complete.

Abstract
Underwater acoustic networks can be quite effective to establish communication links between autonomous underwater vehicles (AUVs) and other vehicles or control units, enabling complex vehicle applications and control scenarios. A communications and control framework to support the use of underwater acoustic networks and sample application scenarios are described for single and multi-AUV operation.

Abstract
The design and development of the Swordfish Autonomous Surface Vehicle (ASV) system is discussed. Swordfish is an ocean capable 4.5m long catamaran designed for network centric operations (with ocean and air going vehicles and human operators). In the basic configuration, Swordfish is both a survey vehicle and a communications node with gateways for broadband, Wi-Fi and GSM transports and underwater acoustic modems. In another configuration, Swordfish mounts a docking station for the autonomous underwater vehicle Isurus from Porto University. Swordfish has an advanced control architecture for multi-vehicle operations with mixed initiative interactions (human operators are allowed to interact with the control loops).

Abstract
We consider the problem of securing routing information in Mobile Ad-hoc Networks (MANETs). Focusing on the Optimized Link State Routing protocol, we devise a feedback reputation mechanism which assesses the integrity of routing control traffic by correlating local routing data with feedback messages sent by the receivers of control traffic. Based on this assessment, misbehaving nodes are shown to be reliably detected and can be adequately punished in terms of their ability to communicate through the network. To the best of our knowledge, this is the first practical implementation of a reputation mechanism in a standardized proactive routing protocol for MANETs.