Ethnic Group Migration Within Britain During 2000-01: A District Level Analysis

Using data from the 2001 Census Special Migration Statistics, this paper explores how migration volumes, propensities and patterns vary between ethnic groups at the local authority district level in Great Britain. Whilst ethnic minority populations show a marked urban-rural contrast, ethnic minority net migration across the country does not reflect the pattern of counterurbanisation shown by the white group. In those districts with non-white shares of population above the national norm, there is evidence of higher white internal net out-migration. However, when we decompose the net migration balances of London’s boroughs, different spatial processes occurring in inner and outer boroughs are revealed and ethnic minority groups are shown to be decentralising from centres of concentration

Internal Migration of Ethnic Groups in England and Wales by Age and District Type

This paper examines how internal migration propensities vary by age and ethnic group using data from level 1 (district) scale in England and Wales extracted from the 2001 Census Special Migration Statistics and from tables specially commissioned from the Office of National Statistics. The paper identifies age-specific variation in migration propensities by ethnic group at national level before examining the spatial patterns of age-specific inter-district migration using the family and class groupings defined in a recent area classification, demonstrating how minority ethnic group propensities and patterns compare with those of white migrants

Modelling commercial vehicle handling and rolling stability

YesThis paper presents a multi-degrees-of-freedom non-linear multibody dynamic model of a three-axle heavy commercial vehicle tractor unit, comprising a subchassis, front and rear leaf spring suspensions, steering system, and ten wheels/tyres, with a semi-trailer comprising two axles and eight wheels/tyres. The investigation is mainly concerned with the rollover stability of the articulated vehicle. The models incorporate all sources of compliance, stiffness, and damping, all with non-linear characteristics, and are constructed and simulated using automatic dynamic analysis of mechanical systems formulation. A constant radius turn test and a single lane change test (according to the ISO Standard) are simulated. The constant radius turn test shows the understeer behaviour of the vehicle, and the single lane change manoeuvre was conducted to show the transient behaviour of the vehicle. Non-stable roll and yaw behaviour of the vehicle is predicted at test speeds .90 km/h. Rollover stability of the vehicle is also investigated using a constant radius turn test with increasing speed. The articulated laden vehicle model predicted increased understeer behaviour, due to higher load acting on the wheels of the middle and rear axles of the tractor and the influence of the semi-trailer, as shown by the reduced yaw rate and the steering angle variation during the constant radius turn. The rollover test predicted a critical lateral acceleration value where complete rollover occurs. Unstable behaviour of the articulated vehicle is also predicted in the single lane change manoeuvre

A study of commercial vehicle brake judder transmission using multi-body dynamic analysis

YesBraking-induced forced vibration, known as brake judder in road vehicles, causes dissatisfaction to drivers and passengers and also damage and possible early failure in components and systems. In this paper, the transmission of judder vibration from the point of generation (the brake friction pair) through the vehicle structure to the driver is investigated for the particular case of a heavy commercial vehicle. The investigation uses a computer simulation multi-body dynamic model based on the automatic dynamic analysis of mechanical systems software to identify any characteristics of the vehicle suspension design that might influence the vibration transmission from the wheel to the driver. The model uses a simplified rigid chassis and cab to lump the chassis parameters, so that the investigation can focus on the front axle/suspension design, which is a beam axle leaf spring arrangement, and the rear axle/suspension assembly, which is a tandem axle bogie design. Results from the modelling indicate that brake judder vibration is transmitted to the chassis of the vehicle through a leaf spring `wind-up¿ mode and a `walking¿ mode associated with the rear tandem axle. Of particular interest is the longitudinal vibration transmitted through the chassis, since this creates a direct vibration transmission path to the cab and driver. The simulation results were compared with the previously published experimental work on the same design of commercial vehicle, and agreement between the predicted and the measured vibration characteristics and frequencies was found. It is concluded that the rear suspension design parameters could affect the transmission of brake judder vibration to the cab and driver and that a tandem rear axle offers some design opportunity to control the transmission of brake judder vibrations from the wheel to the cab and driver. Given that brake judder has so far defied all attempts to eliminate completely from vehicle brake systems, this is potentially an important opportunity

Dynamic gating in the nucleus accumbens: Behavioral state-dependent synchrony with the prefrontal cortex and hippocampus

Contextual and sensory information, goals, and the motor plan to achieve them are integrated in the nucleus accumbens (NA). Although this integration needs flexibility to operate in a variety of environments, models of NA function rarely consider changing behavioral states. Here, intracellular recordings in anesthetized rats revealed rapid changes in the synchronization between NA up states and prefrontal cortical (PFC) local field potentials (LFPs). The synchronization of the NA with the PFC and ventral hippocampus also varied over time in awake rats, depending on the behavioral state of the animal: NA LFPs followed hippocampal theta rhythms during spatial exploration, but not during an operant task when they were instead synchronized with slower PFC rhythms. These data indicate that the ability of the NA to follow cortical inputs can rapidly change, allowing for a mechanism that could select an optimal response for a given behavioral condition

Identifying Native Applications with High Assurance

The work described in this paper investigates the problem of identifying and deterring stealthy malicious processes on a host. We point out the lack of strong application iden- tication in main stream operating systems. We solve the application identication problem by proposing a novel iden- tication model in which user-level applications are required to present identication proofs at run time to be authenti- cated by the kernel using an embedded secret key. The se- cret key of an application is registered with a trusted kernel using a key registrar and is used to uniquely authenticate and authorize the application. We present a protocol for secure authentication of applications. Additionally, we de- velop a system call monitoring architecture that uses our model to verify the identity of applications when making critical system calls. Our system call monitoring can be integrated with existing policy specication frameworks to enforce application-level access rights. We implement and evaluate a prototype of our monitoring architecture in Linux as device drivers with nearly no modication of the ker- nel. The results from our extensive performance evaluation shows that our prototype incurs low overhead, indicating the feasibility of our model

Chaos in a spatially-developing plane mixing layer

A spatially-developing plane mixing layer was analyzed for chaotic behavior. A direct numerical simulation of the Navier-Stokes equations in a 2-D domain infinite in y and having inflow-outflow boundary conditions in x was used for data. Spectra, correlation dimension and the largest Lyapunov exponent were computed as functions of downstream distance x. When forced at a single (fundamental) frequency with maximum amplitude, the flow is periodic at the inflow but becomes aperiodic with increasing x. The aperiodic behavior is caused by the presence of a noisy subharmonic caused by the feedback between the necessarily nonphysical inflow and outflow boundary conditions. In order to overshadow this noise the flow was also studied with the same fundamental forcing and added random forcing of amplitude upsilon prime sub R/delta U = 0.01 at the inlet. Results were qualitatively the same in both cases: for small x, spectral peaks were sharp and dimension was nearly 1, but as x increased a narrowband spectral peak grew, spectra decayed exponentially at high frequencies and dimension increased to greater than 3. Based on these results, the flow appears to exhibit deterministic chaos. However, at no location was the largest Lyapunov exponent found to be significantly greater than zero