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Multiscale modeling of polymers closely coupled to Broad Q neutron scattering from NIMROD
Publication . Gkourmpis, Thomas; Lopez, Daniel; Mitchell, Geoffrey R.
We use data over an extended Q range from 0.01 to 100Å-1 from the recently commissioned NIMROD instrument at the ISIS pulsed neutron source to develop a multi-scale inverse modeling procedure which will provide insight in to the phase transformations of polymer systems. The first level of our procedure is atomistic and we use internal coordinates (bond length, bond angles and torsion angles) to define the polymer chain in full atomistic detail. Values were assigned to each internal coordinate within the chain using a stochastic Monte Carlo method in which the probabilities were drawn from distributions representing the possible range of values. Using this approach, random chain configurations could be rapidly built and the intrachain structure factor calculated utilizing a small set of parameters and compared with the experimental function. Parameters representing the probability distribution functions were systematically varied using a grid search to find the values which gave the best fit to the structure factor for Q > 3Å-1 in order to determine the details of the chain conformation in the molten phase. This process was repeated for data over the same extended Q range obtained at lower temperatures where the polymer was expected to crystallize. Polymers crystallize via chain-folded thin lamellae crystals. Such crystals give rise to an intense peak at Q ∼ 0.03Å-1. This scattering can be calculated using a lamellar stack model, coarse-grained from the single chain structure. We describe this approach using data obtained on the crystallization from the melt phase of perdeuterated polymers. The objective here is to follow the three key length scales; the chain folded lamellar thickness of ∼ 10nm, the crystal unit cell ∼ 1nm and the detail of the chain conformation is ∼ 0.1nm.
Assistive technologies for children with cognitive and/or motor disabilities: a diagnosis of the training needs of informal caregivers
Publication . Almeida, I.; Ribeiro, Jaime; Moreira, A.
Assistive technologies promote communication, personal independence as well as the inclusion of children with cognitive or motor disabilities. Despite the human and material resources available, the implementation of assistive technologies in many family settings is still a struggling task. With the present study we seek to survey information and training needs of informal caregivers related to the use ofassistive technologies at home, so as to, in the near future, try to meet them. Therefore, we are conducting a focus group on that topic with therapists, special education teachers and an educational psychologist and analyzing the content of the discussion. The data gives a perspective on (i) how thorough informal caregivers' knowledge of what assistive technologies and their advantages are, (ii) difficulties reported by informal caregivers when using them with their children, (iii) reasons that may lead them to the abandonment of assistive technology devices, (iv) how they can develop their skills and use the technology more effectively and (v) how information on assistive technologies can be made available to them. Therefore, the full aim of this research is to contribute to reducing technology abandonment and to enhancing its use in the family setting by children with cognitive and/or motor limitations. Some preliminary results are put forward.
Efficient source finding for radio interferometric images
Publication . Lucas, L.; Staley, T.; Scaife, A.
Object detection in astronomical images, generically referred to as source finding, is often performed before the object characterisation stage in astrophysical processing work flows. In radio astronomy, source finding has historically been performed by bespoke off-line systems; however, modern data acquisition systems as well as those proposed for upcoming observatories such as the Square Kilometre Array (SKA), will make this approach unfeasible. One area where a change of approach is particularly necessary is in the design of fast imaging systems for transient studies. This paper presents a number of advances in accelerating and automating the source finding in such systems.
Reliability of AAL Systems Modeled as BPMN Business Processes
Publication . Respício, Ana; Martinho, Ricardo; Domingos, Dulce
The use of Ambient-Assisted Living (AAL) systems has been spreading across several countries, with the ultimate purpose of improving the quality of life of patients. These systems often reflect complex architectures including several components such as sensors, gateways, Information Systems or even actuators, as well as messaging and transmitting protocols. Failures in these systems can have severe impact on a monitored patient, and most components foresee some kind of compensation countermeasures to increase reliability.
Nevertheless, these measures are often self-contained to a single component and
do not address the overall AAL system reliability, disregarding precedent and
successor activities and interactions that exist for each time a certain value is
registered or a certain alert is triggered. In this paper, we propose a new approach
to calculate the overall reliability of an AAL system. We take a Business Process Management (BPM) approach to model the activities and interactions between AAL components, using the Business Process Model and Notation (BPMN) standard. By extending the BPMN standard to include reliability information, we can derive the overall reliability of a certain AAL system. To prove this approach, we also present a reliability study considering scenarios with single and pairwise reliability variations of AAL system components. With this approach, healthcare managers can benefit from important overall reliability information of an AAL system, and better allocate the appropriate resources (including hardware or health care professionals) to improve responsiveness of care to patients.
Computational complexity control for HEVC based on coding tree spatio-temporal correlation
Publication . Correa, Guilherme; Assunção, Pedro; Cruz, Luis A. da Silva; Agostini, Luciano
The High Efficiency Video Coding standard shows improved compression efficiency in comparison to previous standards at the cost of higher computational complexity. In this paper, a complexity control method for HEVC encoders based on the dynamic adjustment of the number of constrained coding treeblocks is proposed. The method limits the maximum tree depth used in the coding structures based on spatio-temporal correlation in order to decrease the number of evaluations performed in the Rate-Distortion Optimization process. Experimental results show that the proposed method is capable of maintaining the encoding time per frame under a pre-defined target, reaching computational complexity decreases of up to 50% at the cost of an average BD-PSNR loss of 0.26 dB in the worst case scenario.