The Crime Victim and the Criminal Justice System: Time for a Change

The failure of the present criminal justice system to provide meaningful participation for victims of crime has launched crime victim reform measures to the forefront of the legislative agenda. This article explores current reform measures and proposes new programs to increase the quantity of victims\u27 rights and enhance the quality of victim involvement

Findings with AVC design for mitigation of human induced vibrations in office floors

PublishedTopics in Dynamics of Civil Structures, Volume 4; Part of the series Conference Proceedings of the Society for Experimental Mechanics Series pp 37-44This is the author accepted manuscript. The final version is available from Springer via the DOI in this record.In recent years, there have been extensive active vibration control (AVC) studies for the mitigation of human induced vibrations in a series of office floors, in which such vibrations are deemed to be 'problematic' and have been found to affect only certain sections of the floors. These floors are predominantly open-plan in layout and comprise of different structural configurations for their respective bays and this influences their dynamic characteristics. Most of the AVC studies have comprised extensive analytical predictions and experimental implementations of different controller schemes. The primary measures of vibration mitigation performance have been by frequency response function (FRF) measurements, responses to controlled walking tests, and in-service monitoring, all tests with and without AVC. This paper looks at AVC studies in three different office floor case studies in past field trials. Some of the estimated modal properties for each of these floors from experimental modal analysis (EMA) tests are shown as well as some selected mode shapes of fundamental modes of vibration. These reflect the variability in their dynamic characteristics by virtue of their different designs and thus the potential for their 'liveliness' under human induced excitation. An overview of some of the controller schemes pursued in the various field trials are mentioned as well as a brief insight being provided into some challenges encountered in their designs and the physical siting of the collocated sensor and actuator pairs used in the field trials. The measure for the vibration mitigation performances in this work is in the form of uncontrolled and controlled point accelerance FRFs which show attenuations in the target modes of vibration between 13 and 18 dB. These tests also show the variability in vibration mitigation performances between the various controllers. © The Society for Experimental Mechanics, Inc. 2013

Approximate pole-placement controller using inverse plant dynamics for floor vibration control

PublishedThis is the final version of the article. Available from SPIE via the DOI in this record.Past research and field trials have demonstrated the viability of active vibration control (AVC) technologies for the mitigation of human induced vibrations in problematic floors. They make use of smaller units than their passive counterparts, provide quicker and more efficient control, can tackle multiple modes of vibration simultaneously and adaptability can be introduced to enhance their robustness. Predominantly single-input-single-output (SISO) and multi-SISO collocated sensor and actuator pairs have been utilized in direct output feedback schemes, for example, with direct velocity feedback (DVF). On-going studies have extended such past works to include model-based control approaches, for example, pole-placement (PP), which demonstrate increased flexibility of achieving desired vibration mitigation performances but for which stability issues must be adequately addressed. The work presented here is an extension to the pole-placement controller design using an algebraic approach that has been investigated in past studies. An approximate pole-placement controller formulated via the inversion of the floor dynamics, considered as minimum phase, is designed to achieve target closed-loop performances. Analytical studies and experimental tests are based on a laboratory structure and comparisons in vibration mitigation performances are made with a typical DVF control scheme with inner loop actuator compensation. It is shown that with minimal compensation, primarily in the form of notch filters and gain adjustment, the approximate pole-placement controller scheme is easily formulated and implemented and offers good vibration mitigation performance as well as the potential for isolation and control of specific target modes of vibration. Predicted attenuations of 22dB and 12dB in both the first and second vibration modes of the laboratory structure were also realized in the experimental studies for DVF and the approximate PP controller. © 2013 SPIE

Fuzzy Logic Controller Scheme for Floor Vibration Control

© 2015 Owned by the authors, published by EDP Sciences. The design of civil engineering floors is increasingly being governed by their vibration serviceability performance. This trend is the result of advancements in design technologies offering designers greater flexibilities in realising more lightweight, longer span and more open-plan layouts. These floors are prone to excitation from human activities. The present research work looks at analytical studies of active vibration control on a case study floor prototype that has been specifically designed to be representative of a real office floor structure. Specifically, it looks at tuning fuzzy control gains with the aim of adapting them to measured structural responses under human excitation. Vibration mitigation performances are compared with those of a general velocity feedback controller, and these are found to be identical in these sets of studies. It is also found that slightly less control force is required for the fuzzy controller scheme at moderate to low response levels and as a result of the adaptive gain, at very low responses the control force is close to zero, which is a desirable control feature. There is also saturation in the peak gain with the fuzzy controller scheme, with this gain tending towards the optimal feedback gain of the direct velocity feedback (DVF) at high response levels for this fuzzy design.The authors would like to acknowledge the financial assistance provided by the UK Engineering and Physical Sciences Research Council (EPSRC) through a responsive mode grant (Ref. EP/H009825/1), a Platform Grant (Ref. EP/G061130/2) and a Leadership Fellowship Grant (Ref. EP/J004081/2). Also acknowledged are the British Council (UK) through the Researcher Links programme and Brazilian institutions CNPq and CAPES financial support

Direct velocity feedback versus a geometric controller design of remotely located vibration control systems

Proceedings of the 5th International Conference on Structural Engineering, Mechanics and Computation, SEMC 2013The mitigation of human induced vibrations in floors continues to be a key area of research particularly as a result of advancement in material and design technologies enabling the design of light, slender and more open plan structures. These floors are typically characterised by low and close natural frequencies as well as low modal damping ratios, and these combinations of factors contribute to their increased susceptibility to human induced vibrations. Amongst the remedial measures pursued to enhance their vibration serviceability performance, active vibration control (AVC) technologies are emerging as a viable technology and predominantly direct output feedback approaches have been pursued in past analytical studies and field trials. It has often been assumed that actuators and sensors can be located where vibration attenuation is desired and this may not always be feasible. The research work presented in this paper compares the vibration mitigation performances of the direct velocity feedback scheme that has been extensively used in past floor vibration control researches against a geometric controller design approach that has been developed to provide a design freedom for reducing vibration in both local and remote locations. The geometric controller design approach assumes the inability to locate the actuators and sensors at the remote location but acknowledges that this measurement can be obtained during the commissioning stage and used during the design phase to enhance both local and remote locations. All the analytical and experimental studies are based on a laboratory structure. The work demonstrates comparable vibration mitigation performances of the dominant mode of vibration of the laboratory structure for both approaches but also demonstrates potential for additional enhancement to the second vibration mode of the laboratory structure with the geometric controller design approach. Approximately 20-25 dB attenuation in the first and second vibration modes of the laboratory structure were achieved. © 2013 Taylor & Francis Group, London, UK.The authors would like to acknowledge the financial assistance provided by the UK Engineering and Physical Sciences Research Council (EPSRC) through a responsive mode grant entitled “Active Control of Human-Induced Vibration” (Ref: EP/H009825/1), Leadership Fellowship grant entitled “Advanced Technologies for Mitigation of Human-Induced Vibration” (Ref: EP/J004081/1) and Platform Grant entitled “Dynamic Performance of Large Civil Engineering Structures: An Integrated Approach to Management, Design and Assessment” (Ref: EP/G061130/1)

Method and apparatus for joining metals

The present invention discloses methods and apparatus for joining of two workpieces. The present invention includes special preparation of the joining ends of the two workpieces to be joined. Methods of the present invention include delivering a high current, low voltage pulse to a pair of workpieces to be joined while applying and maintaining a constantly high load on said workpieces to thereby join the workpieces.Board of Regents, University of Texas Syste

Microflare Heating of a Solar Active Region Observed with NuSTAR, Hinode/XRT, and SDO/AIA

NuSTAR is a highly sensitive focusing hard X-ray (HXR) telescope and has observed several small microflares in its initial solar pointings. In this paper, we present the first joint observation of a microflare with NuSTAR and Hinode/XRT on 2015 April 29 at ~11:29 UT. This microflare shows heating of material to several million Kelvin, observed in Soft X-rays (SXRs) with Hinode/XRT, and was faintly visible in Extreme Ultraviolet (EUV) with SDO/AIA. For three of the four NuSTAR observations of this region (pre-, decay, and post phases) the spectrum is well fitted by a single thermal model of 3.2-3.5 MK, but the spectrum during the impulsive phase shows additional emission up to 10 MK, emission equivalent to A0.1 GOES class. We recover the differential emission measure (DEM) using SDO/AIA, Hinode/XRT, and NuSTAR, giving unprecedented coverage in temperature. We find the pre-flare DEM peaks at ~3 MK and falls off sharply by 5 MK; but during the microflare's impulsive phase the emission above 3 MK is brighter and extends to 10 MK, giving a heating rate of about $2.5 \times 10^{25}$ erg s$^{-1}$. As the NuSTAR spectrum is purely thermal we determined upper-limits on the possible non-thermal bremsstrahlung emission. We find that for the accelerated electrons to be the source of the heating requires a power-law spectrum of $\delta \ge 7$ with a low energy cut-off $E_{c} \lesssim 7$ keV. In summary, this first NuSTAR microflare strongly resembles much more powerful flares.Comment: Accepted for publication in ApJ. 14 pages with 12 figures and 1 tabl

Multichannel quantum-defect theory for ultracold atom-ion collisions

We develop an analytical model for ultracold atom-ion collisions using the multichannel quantum-defect formalism. The model is based on the analytical solutions of the r^-4 long-range potential and on the application of a frame transformation between asymptotic and molecular bases. This approach allows the description of the atom-ion interaction in the ultracold domain in terms of three parameters only: the singlet and triplet scattering lengths, assumed to be independent of the relative motion angular momentum, and the lead dispersion coefficient of the asymptotic potential. We also introduce corrections to the scattering lengths that improve the accuracy of our quantum-defect model for higher order partial waves, a particularly important result for an accurate description of shape and Feshbach resonances at finite temperature. The theory is applied to the system composed of a 40Ca+ ion and a Na atom, and compared to numerical coupled-channel calculations carried out using ab initio potentials. For this particular system, we investigate the spectrum of bound states, the rate of charge-transfer processes, and the collision rates in the presence of magnetic Feshbach resonances at zero and finite temperature.Comment: 39 pages, 21 figure