Fine-tuning a context-aware system application by using user-centred design methods

Context-Aware Systems in the home environment can provide an effective solution for supporting wellbeing and autonomy for the elderly. The definition and implementation of the system architecture for a particular assisted living healthcare application entail both technological and usability challenges. If issues regarding users’ concerns and desires are taken into account in the early stages of the system development users can benefit substantially more from this technology. In this paper, we describe our initial experiences with different user-centred design methods, as they are applied in the process of fine-tuning a context-aware system architecture to improve quality of life for elderly THR patients (Total Hip Replacement). The insights resulting from this approach result in a clearer functional specification towards a better fit with the user needs regarding information need of the patient as well as the physiotherapist. Important system requirements as timing and content of the feedback are much more fruitful in an earlier phase of the development process. User-centred design methods help to better understand the needed functional features of a context-aware system, thereby saving time and helping developers to improve adoption of the system by the users

Run-time Energy Management for Mobiles

Due to limited energy resources, mobile computing requires an energy-efficient a rchitecture. The dynamic nature of a mobile environment demands an architecture that allows adapting to (quickly) changing conditions. The mobile has to adapt d ynamically to new circumstances in the best suitable manner. The hardware and so ftware architecture should be able to support such adaptability and minimize the energy consumption by making resource allocation decisions at run-time. To make these decisions effective, a tradeoff has to be made between computation , communication and initialization costs (both time and energy). This paper describes our approach to construct a model that supports taking such decisions

Mapping the SISO module of the Turbo decoder to a FPFA

In the CHAMELEON project a reconfigurable systems-architecture, the Field Programmable Function Array (FPFA) is introduced. FPFAs are reminiscent to FPGAs, but have a matrix of ALUs and lookup tables instead of Configurable Logic Blocks (CLBs). The FPFA can be regarded as a low power reconfigurable accelerator for an application specific domain. In this paper we show how the SISO (Soft Input Soft Output) module of the Turbo decoding algorithm can be mapped on the reconfigurable FPFA

Parameter reduction for the Yld2004-18p yield criterion

The Yld2004-18p yield criterion uses 18 parameters to define anisotropy for a full 3D stress state. It is demonstrated in this paper that dependencies between the parameters exist and for a given set of experimental data the parameters are not uniquely defined. Analysis of the yield function shows that two specific combinations of parameters do not contribute to the value of the yield function. Therefore, the number of parameters can be reduced to 16, without any loss of flexibility. Similarly, the number of parameters for the plane stress version of this yield criterion reduces from 14 to 12.1111Ysciescopu

Increased hepatobiliary and fecal cholesterol excretion upon activation of the liver X receptor is independent of ABCA1

The ATP-binding cassette transporter ABCA1 is essential for high density lipoprotein (HDL) formation and considered rate-controlling for reverse cholesterol transport. Expression of the Abca1 gene is under control of the liver X receptor (LXR). We have evaluated effects of LXR activation by the synthetic agonist T0901317 on hepatic and intestinal cholesterol metabolism in C57BL/6J and DBA/1 wild-type mice and in ABCA1-deficient DBA/1 mice. In wild-type mice, T0901317 increased expression of Abca1 in liver and intestine, which was associated with a similar to60% rise in HDL. Biliary cholesterol excretion rose 2.7-fold upon treatment, and fecal neutral sterol output was increased by 150-300%. Plasma cholesterol levels also increased in treated Abca1(-/-) mice (+120%), but exclusively in very low density lipoprotein-sized fractions. Despite the absence of HDL, hepatobiliary cholesterol output was stimulated upon LXR activation in Abca1(-/-) mice, leading to a 250% increase in the biliary cholesterol/phospholipid ratio. Most importantly, fecal neutral sterol loss was induced to a similar extent (+300%) by the LXR agonist in DBA/1 wild-type and Abca1(-/-) mice. Expression of Abcg5 and Abcg8, recently implicated in biliary excretion of cholesterol and its intestinal absorption, was induced in T0901317-treated mice. Thus, activation of LXR in mice leads to enhanced hepatobiliary cholesterol secretion and fecal neutral sterol loss independent of (ABCA1-mediated) elevation of HDL and the presence of ABCA1 in liver and intestine

On the thermoelectricity of correlated electrons in the zero-temperature limit

The Seebeck coefficient of a metal is expected to display a linear temperature-dependence in the zero-temperature limit. To attain this regime, it is often necessary to cool the system well below 1K. We put under scrutiny the magnitude of this term in different families of strongly-interacting electronic systems. For a wide range of compounds (including heavy-fermion, organic and various oxide families) a remarkable correlation between this term and the electronic specific heat is found. We argue that a dimensionless ratio relating these two signatures of mass renormalisation contains interesting information about the ground state of each system. The absolute value of this ratio remains close to unity in a wide range of strongly-correlated electron systems.Comment: 15 pages, including two figure

A Distributed and Self-Organizing Scheduling Algorithm for Energy-Efficient Data Aggregation in Wireless Sensor Networks

Wireless sensor networks (WSNs) are increasingly being used to monitor various parameters in a wide range of environmental monitoring applications. In many instances, environmental scientists are interested in collecting raw data using long-running queries injected into a WSN for analyzing at a later stage, rather than injecting snap-shot queries containing data-reducing operators (e.g., MIN, MAX, AVG) that aggregate data. Collection of raw data poses a challenge to WSNs as very large amounts of data need to be transported through the network. This not only leads to high levels of energy consumption and thus diminished network lifetime but also results in poor data quality as much of the data may be lost due to the limited bandwidth of present-day sensor nodes. We alleviate this problem by allowing certain nodes in the network to aggregate data by taking advantage of spatial and temporal correlations of various physical parameters and thus eliminating the transmission of redundant data. In this article we present a distributed scheduling algorithm that decides when a particular node should perform this novel type of aggregation. The scheduling algorithm autonomously reassigns schedules when changes in network topology, due to failing or newly added nodes, are detected. Such changes in topology are detected using cross-layer information from the underlying MAC layer. We first present the theoretical performance bounds of our algorithm. We then present simulation results, which indicate a reduction in message transmissions of up to 85% and an increase in network lifetime of up to 92% when compared to collecting raw data. Our algorithm is also capable of completely eliminating dropped messages caused by buffer overflow

Palynological evidence for environmental and climatic change in the lower Guadiana valley, Portugal, during the last 13 000 years

Pollen analysis of a 48 m AMS radiocarbon-dated sediment sequence from the Guadiana estuary provides the first record of Lateglacial and Holocene vegetation history in the Algarve province of Portugal. This paper focuses on the record of terrestrial pollen taxa, which document a series of forest expansions and declines during the period 13 000 cal. BP to 1600 cal. BP and provide insights into climate evolution in southwestern Iberia. The main vegetation phases identified in the Guadiana valley are (1) Lateglacial interstadial (Allerød) forest with Quercus and Pinus under a temperate, moist, continental climate; (2) a Younger Dryas forest decline (Quercus) and expansion of pinewoods, xeric scrub and open ground habitats (with Juniperus, Artemisia, Ephedra distachya type, Centaurea scabiosa type) under arid and cold conditions; (3) an early Holocene forest/scrub/open-ground vegetation mosaic developing under a warm, dry and continental climate; (4) a maximum of Quercus forest and thermomediterranean evergreen taxa (Olea, Phillyrea, Pistacia) reflecting a warm, moist oceanic climate between c. 9000 cal. BP and c. 5000 cal. BP; and (5) the expansion of shrublands with Cistaceae and Ericaceae under a drier climatic regime and increasing anthropogenic activity since c. 5000 cal. BP. Holocene episodes of maximum climatic aridity are identified in the record of xerophytic taxa (Juniperus, Artemisia, Ephedra distachya type) centred around 10 200 cal. BP, 7800 cal. BP, 4800 cal. BP, 3100 cal. BP and 1700 cal. BP. Regional comparisons suggest a correlation of arid phases across southern Iberia and northwest Africa, which can be related to abrupt North Atlantic coolings (Bond events).Research Council studentship for WJF (NERC/S/A/2001/06109), with the support of Trinity College and the Department of Geography, University of Cambridg

Using body sensors for evaluating the impact of smart cycling technologies on cycling experiences:a systematic literature review and conceptual framework

Digital technologies in, on, and around bicycles and cyclists are gaining ground. Collectively called Smart Cycling Technologies (SCTs), it is important to evaluate their impact on subjective cycling experiences. Future evaluations can inform the design of SCTs, which in turn can help to realize the abundant benefits of cycling. Wearable body sensors and advanced driver assistance systems are increasingly studied in other domains, however evaluation methods integrating such sensors and systems in the field of cycling research were under-reviewed and under-conceptualized. This paper therefore presents a systematic literature review and conceptual framework to support the use of body sensors in evaluations of the impact of SCTs on perceptions, emotions, feelings, affect, and more, during outdoor bicycle rides. The literature review (n = 40) showed that there is scarce research on this specific use of body sensors. Moreover, existing research designs are typically not tailored to determine impact of SCTs on cycling experience at large scale. Most studies had small sample sizes and explored limited sensors in chest belts and wristbands for evaluating stress response. The evaluation framework helps to overcome these limitations, by synthesizing crucial factors and methods for future evaluations in four categories: (1) experiences with SCTs, (2) experience measurements, (3) causal analysis, (4) confounding variables. The framework also identifies which types of sensors fit well to which types of experiences and SCTs. The seven directions for future research include, for example, experiences of psychological flow, sensors in e-textiles, and cycling with biofeedback. Future interactions between cyclists and SCTs will likely resemble a collaboration between humans and artificial intelligence. Altogether, this paper helps to understand if future support systems for cyclists truly make cycling safer and more attractive