Restrictions on Aliens in the United Kingdom, 1914-1919 : a Study of the Origins and Political Background of the Aliens Restrictions Acts of 1914 and 1919.

At first glance the Aliens Restriction Act of 1914, which was introduced and passed on the first day of World War One, seems a hasty and ill-prepared piece of legislation. Actually, when examined in the light of Arthur Marwick's thesis that war is a forcing house for pre-existent social and governmental ideas, it becomes clear that the act was not after all the product of hastily formed notions. In point of fact it followed the precedent of detailed draft clauses produced in 1911 by a sub-committee of the Committee of Imperial Defence established to consider the treatment of aliens in the event of war. Indeed the draft clauses and the restrictions embodied in the 1914 act were strikingly similar to restrictions on aliens legislated in 1793. Hostility to aliens had been growing from 1905 to 1914 and this hostility blossomed into xeno-phobia on the outbreak of war, a crucial precondition for the specifically anti-enemy fears of the time. In 1919 the Aliens Restriction (Amendment) Bill was introduced into parliament to extend temporarily the provisions of the 1914 act thus permitting the Home Secretary to plan permanent, detailed legislation. Two minority groups of MPs with extreme views on the treatment of aliens were prominent in the debates on this bill. The extreme Liberal group which advocated leniency in the treatment of aliens had little effect on the final form of the bill, but the extreme Conservative group, which demanded severe restrictions on aliens, succeeded in persuading the government to include detailed restrictions. Despite its allegedly temporary nature, the Aliens Restriction (Amendment) Act of 1919 was renewed annually until 1971.

Towards Mapping of Rock Walls Using a UAV-Mounted 2D Laser Scanner in GPS Denied Environments

In geotechnical engineering, the stability of rock excavations and walls is estimated by using tools that include a map of the orientations of exposed rock faces. However, measuring these orientations by using conventional methods can be time consuming, sometimes dangerous, and is limited to regions of the exposed rock that are reachable by a human. This thesis introduces a 2D, simulated, quadcopter-based rock wall mapping algorithm for GPS denied environments such as underground mines or near high walls on surface. The proposed algorithm employs techniques from the field of robotics known as simultaneous localization and mapping (SLAM) and is a step towards 3D rock wall mapping. Not only are quadcopters agile, but they can hover. This is very useful for confined spaces such as underground or near rock walls. The quadcopter requires sensors to enable self localization and mapping in dark, confined and GPS denied environments. However, these sensors are limited by the quadcopter payload and power restrictions. Because of these restrictions, a light weight 2D laser scanner is proposed. As a first step towards a 3D mapping algorithm, this thesis proposes a simplified scenario in which a simulated 1D laser range finder and 2D IMU are mounted on a quadcopter that is moving on a plane. Because the 1D laser does not provide enough information to map the 2D world from a single measurement, many measurements are combined over the trajectory of the quadcopter. Least Squares Optimization (LSO) is used to optimize the estimated trajectory and rock face for all data collected over the length of a light. Simulation results show that the mapping algorithm developed is a good first step. It shows that by combining measurements over a trajectory, the scanned rock face can be estimated using a lower-dimensional range sensor. A swathing manoeuvre is introduced as a way to promote loop closures within a short time period, thus reducing accumulated error. Some suggestions on how to improve the algorithm are also provided.