New Releases by David Christian

A Rotorcraft UAV provides an ideal experimental platform for vision-based navigation. This thesis describes the flight tests of the US Army PALACE project, which implements Moravec''s pseudo-normalized correlation tracking algorithm. The tracker uses the movement of the landing site in the camera, a laser range, and the aircraft attitude from an IMU to estimate the relative motion of the UAV. The position estimate functions as a GPS equivalent to enable the rotorcraft to maneuver without the aid of GPS. Flight tests were performed with obstacles and over concrete, asphalt, and grass in daylight conditions with a safe landing area determined by a separate method. The tracking algorithm and position estimation performance are compared to GPS. Accurate time synchronization of the inputs to the position estimation algorithm directly affect the closed-loop stability of the system, proportional with altitude. By identifying the frequency response of each input and adding filters to delay some of the inputs, the closed-loop system maintains stable flight above 18 m above ground, where the system was unstable without the additional filters.

Because concurrent programming as a field is still maturing, and access to massively parallel machines is restricted to large businesses and universities, there is a dearth of debuggers for concurrent programs. Those that do exist are usually difficult to obtain. This project helps alleviate these problems by creating a freely available debugger for concurrent programs written using the MPI (Message Passing Interface) protocol. A survey of the current field of debuggers was completed, out of which a design focused on user interface issues and replay capability developed. Testing shows the debugger to be an effective tool.

Realms of the Silk Roads Part 1: New Sources on Inner Asian History N. Sims-Williams, Some Reflections on Zoroastrianism in Sogdiana and Bactria; G. Mikkelsen, Traite/Sermon on the Light-Nous in Chinese and its Parallels in the Parthian, Sogdian and Old Turkish; A.V.G. Betts & V.N. Yagodin, Hunting Traps on the Ustiurt Plateau, Uzbekistan. Part 2: Long Distance Contacts S. Lieu, Byzantium, Persia and China: Interstate Relations on the Eve of the Islamic Conquest; D. Christian, Silk Roads or Steppe Roads ? The Silk Roads in World History; M. Underdown, The Northern Silk Road: Ties between Turfan and Korea. Part 3: Political Life C. Benjamin, The Yuezhi and their Neighbours: Evidence for the Yuezhi in the Chinese Sources c. 220 - c. 25 BCE; K. Nourzhanov, Politics of National Reconciliation in Tajikistan: From Peace Talks to (Partial) Political Settlements; S. Akbarzadeh, Islam and Regional Stability in Central Asia; C. Mackerras, Relations Between the Uygur State and China''s Tang Dynasty, 744-840. Part 4: Perspectives G. Watson, Prestigious Peregrinations : British Travellers in Central Asia c. 1830-1914; F. Patrikeeff, The Geopolitics of Myth: Interwar Northeast Asia and Images of an Inner Asian Empire; D. Thwaites, The Road to Urumqui: Zunun Kadir''s Lost World; F. Patrikeeff & J. Perkins, National and Imperial Identity: A Triptych of Baltic Germans in Inner Asia. Part 5: Teaching Inner Asian History R. Fletcher & E. Hetherington, The China TimeMap Project: China and the Silk Roads; M. With, Creating Responsible Educational Images of Judaic / Christian / Islamic Relations.

It is impossible to make sense of the modern world without understanding the vast, and ultimately unsuccessful, experiment with Communism that began in Russia in 1917. Imperial and Soviet Russia offers a coherent interpretation of the turbulent history of the Russian Empire and the Soviet Union during the last two centuries. Tracing the roots of the Communist experiment in the peasant world of traditional Russia, it shows how the harsh social and economic changes of the nineteenth century created enough dislocation to topple the tsarist regime and bring the Bolsheviks to power in 1917.

Revised edition of a book first published in 1986. This edition has been updated and expanded to include new chapters on the Brezhnev era and perestroika and to take into account the dissolution of the Soviet system. The text is well illustrated and is supported by a statistical appendix, an annotated bibliography, a glossary, chronology and an index.

"The formation of patterns of functionally appropriate chemical synapses is one of the key aspects of nervous system development. I have investigated the cellular interactions that culminate in the formation of an inhibitory synapse between the R and P neurons of the leech. These neurons may be isolated and maintained in culture, where they reform synaptic connections under easily manipulable conditions. An early event in the formation of this synapse is the loss from sites of contact in the postsynaptic P cell of an excitatory response to the transmitter serotonin. The loss of this response was triggered specifically by contact with the presynaptic R neuron, and not by contact with other leech neurons, including other serotonergic neurons. Furthermore, contact with the R neurons of the reproductive ganglia, which do not innervate P cells, was also ineffective in causing the loss of response. This highly specific cellular interaction was prevented by treatment of the R cell surface with the proteolytic enzyme trypsin or with the lectin wheat germ agglutinin (WGA), suggesting involvement of an R cell surface glycoprotein. WGA blocked not only the loss of the excitatory response, but also prevented the formation of the R-P synapse. An antibody library against the R cell generated using a novel phage-display system produced antibodies which bound to subsets of leech neurons, including the R neurons, but none of these was specific for the R cells. I conclude that an early event in the formation of the R-P synapse is the recognition by the P cell of its correct synaptic partner through an R cell-specific surface molecule." --