Optical alignment system Patent

Electro-optical/computer system for aligning large structural members and maintaining correct positio

Optimum noncoherent FM-DCSK detector : application of chaotic GML decision rule

Author name used in this publication: Francis C. M. LauAuthor name used in this publication: Chi K. TseRefereed conference paper2003-2004 > Academic research: refereed > Refereed conference paperVersion of RecordPublishe

Energies And Damping Rates of Elementary Excitations in Spin-1 Bose-einstein-condensed Gases

The finite temperature Green's function technique is used to calculate the energies and damping rates of the elementary excitations of homogeneous, dilute, spin-1 Bose gases below the Bose-Einstein condensation temperature in both the density and spin channels. For this purpose a self-consistent dynamical Hartree-Fock model is formulated, which takes into account the direct and exchange processes on equal footing by summing up certain classes of Feynman diagrams. The model is shown to satisfy the Goldstone theorem and to exhibit the hybridization of one-particle and collective excitations correctly. The results are applied to gases of Na-23 and Rb-87 atoms

On the origin of domestic and international terrorism

We analyze the determinants of the origin of domestic and international terrorism in a large panel data set of 159 countries spanning from 1970 to 2007. We show that terror increases with GDP per capita, a higher POLITY score measuring a more open and competitive political system and experiences of domestic conflict, anarchy and regime transitions. Our evidence thus contradicts the notion that terrorism is rooted in economic deprivation or that strongly autocratic regimes breed more terrorists. Rather we show that weak or failing states are a hotbed for terrorism. Lastly, we show that domestic terror is determined by similar forces as international terror

Mathematical models fof simulation of continuous grinding process with recirculation

New mathematical and computer models and simulation programs were elaborated for studying processes of continuous grinding mills working with classification and partial recirculation of the product. The computer models were developed on the basis of the axial dispersion model taking into consideration also the effects of the mixing of the material to be ground. The effects of changes of parameters of both the mill and the material were studied. The stationary states of the continuous grinding mills working with and without classification and recirculation were compared to each other. The mathematical models and the computer programs developed are suitable for computing the processes of the grinding mills either with or without recirculation. They are usable for simulation based analysis and design of both continuous and batch grinding devices

On the heterogeneity of terror

The existing literature on the determinants of terrorism treats terror as a uniform phenomenon and does not distinguish between different types of terror. This paper explicitly addresses the heterogeneity of terror by classifying groups according to their ideologies. We show that the pattern of terror and its determinants differ strongly for different types of terror. We analyze determinants of domestic and international terrorism, for target and origin using the Global Terrorism Database and show that there have been major shifts in terror activity and composition over time

Political business cycles in local Indonesia

We study political business cycles (PBC) in newly democratized and decentralized Indonesia at the local level. As the timing of indirect and later on direct elections of district heads differs exogenously across jurisdictions, the political business cycle effect is clearly identified . Our data allow distinguishing PBCs for indirect and direct elections. We find significant budget cycles for discretionary budget categories at the disposal of the district head (not for the overall budget) only for direct elections, not for indirect elections. These cycles are much larger if the incumbent runs for reelection. Our results underline the conditional nature of PBC

A global study of hot flow anomalies using Cluster multi-spacecraft measurements

Hot flow anomalies (HFAs) are studied using observations of the magnetometer and the plasma instrument aboard the four Cluster spacecraft. We study several specific features of tangential discontinuities on the basis of Cluster measurements from the time periods of February–April 2003, December 2005–April 2006 and January–April 2007, when the separation distance of spacecraft was large. The previously discovered condition (Facskó et al., 2008) for forming HFAs is confirmed, i.e. that the solar wind speed and fast magnetosonic Mach number values are higher than average. Furthermore, this constraint is independent of the Schwartz et al. (2000)’s condition for HFA formation. The existence of this new condition is confirmed by simultaneous ACE magnetic field and solar wind plasma observations at the L1 point, at 1.4 million km distance from the Earth. The temperature, particle density and pressure parameters observed at the time of HFA formation are also studied and compared to average values of the solar wind plasma. The size of the region affected by the HFA was estimated by using two different methods. We found that the size is mainly influenced by the magnetic shear and the angle between the discontinuity normal and the Sun-Earth direction. The size grows with the shear and (up to a certain point) with the angle as well. After that point it starts decreasing. The results are compared with the outcome of recent hybrid simulations