1,651 research outputs found
UML profile for modeling product observation.
Nowadays interactive electronics products offer a huge functionality to prospective customers, but often it is too huge and complex to be grasped and used successfully. In this case, customers obviate the struggle and return the products to the shop. Also the variability in scope and features of a product is so large that an up-front specification becomes hard if not impossible. To avoid the problem of an inadequate match between customer expectations and designer assumptions, new sources of product usage information have to be developed. One possibility is to integrate observation functionality into the products, continuously involving real users in the product development process. The integration of such functionality is an often overlooked challenge that should be tackled with an appropriate engineering methodology. This paper presents on-going work about a novel design for observation approach that supports early observation integrations and enables the cooperation with various information stakeholders. We show how observation can be embedded seamlessly in a model-driven development process using UML. An industrial case-study shows the feasibility of the approach
Reproducability of corticomuscular coherence:A comparison between static and perturbed tasks
Corticomuscular coherence (CMC) is used to quantify functional corticomuscular coupling during a static motor task. Although the reproducibility of CMC characteristics such as peak strength and frequency within one session is good, reproducibility of CMC between sessions is limited (Pohja et al. 2005, NeuroImage). Reproducible CMC characteristics are required in order to assess changes in corticomuscular coupling in a longitudinal study design, for example during rehabilitation. We recently demonstrated that the presence of CMC in the population in substantially increased when position perturbations are applied during an isotonic force task. Here, we assessed the reproducibility of perturbed CMC compared to unperturbed CMC. Subjects (n=10) performed isotonic wrist flexion contractions against the handle of a wrist manipulator (WM) while EEG (64 channels) and EMG of the m.flexor carpi radialis were recorded in two experimental sessions separated by at least one week. The handle of the WM either kept a neutral angle (baseline task) or imposed a small angle perturbation (perturbed task). In the baseline task, 3 subjects had significant CMC in both the first and the second sessions. In the other 7 subjects no significant CMC was found in both sessions. Between sessions, significant CMC was always found in overlapping frequency bands and generally on overlapping electrodes. In the subjects with CMC a significant cross correlation coefficient between the spectra in the two sessions was present (mean 0.57; 0.3 - 0.79). In the perturbed task CMC was present in 8 subjects in both sessions and absent in 1 subject in the two sessions. One subject had CMC only in the second session. For the subjects with CMC, the correlation coefficient between the spectra of the two sessions was significantly larger than zero with a mean of 0.68 (range 0.38 - 0.88). The presence and absence of CMC within subjects could be reproduced very well between the sessions. This was also demonstrated by the significant correlation between the spectra in the two sessions ; the degree of correlation was variable over subjects both in the baseline and the perturbed task. The reproducibility characteristics of CMC in a perturbed task are comparable or slightly better with respect to an unperturbed task. However, comparison is limited by the small number of subjects with CMC in the baseline task. Perturbed CMC is present in more subjects, which is crucial when developing methods to track corticomuscular coupling over multiple sessions, for example during rehalibitation.handles MIMO systems, and can deal with short measurement time
The Potential of Hyperspectral Patterns of Winter Wheat to Detect Changes in Soil Microbial Community Composition
Reliable information on soil status and crop health is crucial for detecting and mitigating disasters like pollution or minimizing impact from soil-borne diseases. While infestation with an aggressive soil pathogen can be detected via reflected light spectra, it is unknown to what extent hyperspectral reflectance could be used to detect overall changes in soil biodiversity. We tested the hypotheses that spectra can be used to (1) separate plants growing with microbial communities from different farms; (2) to separate plants growing in different microbial communities due to different land use; and (3) separate plants according to microbial species loss. We measured hyperspectral reflectance patterns of winter wheat plants growing in sterilized soils inoculated with microbial suspensions under controlled conditions. Microbial communities varied due to geographical distance, land use and microbial species loss caused by serial dilution. After 3 months of growth in the presence of microbes from the two different farms plant hyperspectral reflectance patterns differed significantly from each other, while within farms the effects of land use via microbes on plant reflectance spectra were weak. Species loss via dilution on the other hand affected a number of spectral indices for some of the soils. Spectral reflectance can be indicative of differences in microbial communities, with the Renormalized Difference Vegetation Index the most common responding index. Also, a positive correlation was found between the Normalized Difference Vegetation Index and the bacterial species richness, which suggests that plants perform better with higher microbial diversity. There is considerable variation between the soil origins and currently it is not possible yet to make sufficient reliable predictions about the soil microbial community based on the spectral reflectance. We conclude that measuring plant hyperspectral reflectance has potential for detecting changes in microbial communities yet due to its sensitivity high replication is necessary and a strict sampling design to exclude other ‘noise’ factors.</p
Stretch Evoked Potentials in Healthy Subjects and After Stroke: A Potential Measure for Proprioceptive Sensorimotor Function
Sensory feedback is of vital importance in motor control, yet rarely assessed in diseases with impaired motor function like stroke. Muscle stretch evoked potentials (StrEPs) may serve as a measure of cortical sensorimotor activation in response to proprioceptive input. The aim of this study is: 1) to determine early and late features of the StrEP and 2) to explore whether StrEP waveform and features can be measured after stroke. Consistency of StrEP waveforms and features was evaluated in 22 normal subjects. StrEP features and similarity between hemispheres were evaluated in eight subacute stroke subjects. StrEPs of normal subjects had a consistent shape across conditions and sessions (mean cross correlation waveforms > 0.75). Stroke subjects showed heterogeneous StrEP waveforms. Stroke subjects presented a normal early peak (40 ms after movement onset) but later peaks had abnormal amplitudes and latencies. No significant differences between stroke subjects with good and poor motor function were found (P > 0.14). With the consistent responses of normal subjects the StrEP meets a prerequisite for potential clinical value. Recording of StrEPs is feasible even in subacute stroke survivors with poor motor function. How StrEP features relate to clinical phenotypes and recovery needs further investigatio
Biotic responses to climate extremes in terrestrial ecosystems
Anthropogenic climate change is increasing the incidence of climate extremes. Consequences of climate extremes on biodiversity can be highly detrimental,
yet few studies also suggest beneficial effects of climate extremes on certain organisms. To obtain a general understanding of ecological responses to climate extremes, we present a review of how 16 major taxonomic/functional groups
(including microorganisms, plants, invertebrates, and vertebrates) respond during
extreme drought, precipitation, and temperature.Most taxonomic/functional
groups respond negatively to extreme events, whereas groups such as mosses,
legumes, trees, and vertebrate predators respond most negatively to climate extremes. We further highlight that ecological recovery after climate extremes is
challenging to predict purely based on ecological responses during or immediately
after climate extremes. By accounting for the characteristics of the recovering
species, resource availability, and species interactions with neighboring
competitors or facilitators, mutualists, and enemies, we outline a conceptual
framework to better predict ecological recovery in terrestrial ecosystems
Semantic concepts in product usage monitoring and analysis
Nowadays, complex electronic products, such as DVD players or mobile phones, offer a huge number of functions. As a consequence of the complexity of the devices, customers often have problems to use such products effectively. For example, it has been observed that an increasing number of technically sound products is returned due to, e.g., interaction problems. One possible root cause of this problem is that most product development processes are still too technologydriven, i.e., potential users are brought into contact with the product only at a very late stage. If early consumer tests are carried out, then these typically aim at abstract market evaluations rather than formulating concrete requirements towards the functionality of the product. As a result, products often have little meaning or relevance to the customers. Therefore, we need better ways to involve users in the development of such products. This can be achieved by observing product usage in the field and incorporating the gained knowledge in the product creation process. This paper proposes an approach to build automatic observation modules into products, collect usage data, and analyze these data by means of process mining techniques exploiting a novel semantic link between observation and analysis. This link yields two main benefits: (i) it adds focus to the potential mass of captured data items; and (ii) it reduces the need for extensive post-processing of the collected data. Together, these two benefits speed up the information feedback cycle towards development
Crop yield gap and stability in organic and conventional farming systems
A key challenge for sustainable intensification of agriculture is to produce increasing amounts of food and feed with minimal biodiversity loss, nutrient leaching, and greenhouse gas emissions. Organic farming is considered more sustainable, however, less productive than conventional farming. We analysed results from an experiment started under identical soil conditions comparing one organic and two conventional farming systems. Initially, yields in the organic farming system were lower, but approached those of both conventional systems after 10-13 years, while requiring lower nitrogen inputs. Unexpectedly, organic farming resulted in lower coefficient of variation, indicating enhanced spatial stability, of pH, nutrient mineralization, nutrient availability, and abundance of soil biota. Organic farming also resulted in improved soil structure with higher organic matter concentrations and higher soil aggregation, a profound reduction in groundwater nitrate concentrations, and fewer plant-parasitic nematodes. Temporal stability between the three farming systems was similar, but when excluding years of Phytophthora outbreaks in potato, temporal stability was higher in the organic farming system. There are two non-mutually exclusive mechanistic explanations for these results. First, the enhanced spatial stability in the organic farming system could result from changes in resource-based (i.e. bottom-up) processes, which coincides with the observed higher nutrient provisioning throughout the season in soils with more organic matter. Second, enhanced resource inputs may also affect stability via increased predator-based (i.e. top-down) control. According to this explanation, predators stabilize population dynamics of soil organisms, which is supported by the observed higher soil food web biomass in the organic farming system.We conclude that closure of the yield gap between organic and conventional farming can be a matter of time and that organic farming may result in greater spatial stability of soil biotic and abiotic properties and soil processes. This is likely due to the time required to fundamentally alter soil properties.Article / Letter to editorCentrum voor Milieuwetenschappen Leide
Soil biodiversity: functions, threats and tools for policy makers
Human societies rely on the vast diversity of benefits provided by nature, such as food, fibres, construction materials, clean water, clean air and climate regulation. All the elements required for these ecosystem services depend on soil, and soil biodiversity is the driving force behind their regulation. With 2010 being the international year of biodiversity and with the growing attention in Europe on the importance of soils to remain healthy and capable of supporting human activities sustainably, now is the perfect time to raise awareness on preserving soil biodiversity. The objective of this report is to review the state of knowledge of soil biodiversity, its functions, its contribution to ecosystem services and its relevance for the sustainability of human society. In line with the definition of biodiversity given in the 1992 Rio de Janeiro Convention, soil biodiversity can be defined as the variation in soil life, from genes to communities, and the variation in soil habitats, from micro-aggregates to entire landscapes. Bio Intelligence Service, IRD, and NIOO, Report for European Commission (DG Environment
Herbivory and dominance shifts among exotic and congeneric native plant species during plant community establishment
Invasive exotic plant species often have fewer natural enemies and suffer less damage from herbivores in their new range than genetically or functionally related species that are native to that area. Although we might expect that having fewer enemies would promote the invasiveness of the introduced exotic plant species due to reduced enemy exposure, few studies have actually analyzed the ecological consequences of this situation in the field. Here, we examined how exposure to aboveground herbivores influences shifts in dominance among exotic and phylogenetically related native plant species in a riparian ecosystem during early establishment of invaded communities. We planted ten plant communities each consisting of three individuals of each of six exotic plant species as well as six phylogenetically related natives. Exotic plant species were selected based on a rapid recent increase in regional abundance, the presence of a congeneric native species, and their co-occurrence in the riparian ecosystem. All plant communities were covered by tents with insect mesh. Five tents were open on the leeward side to allow herbivory. The other five tents were completely closed in order to exclude insects and vertebrates. Herbivory reduced aboveground biomass by half and influenced which of the plant species dominated the establishing communities. Exposure to herbivory did not reduce the total biomass of natives more than that of exotics, so aboveground herbivory did not selectively enhance exotics during this early stage of plant community development. Effects of herbivores on plant biomass depended on plant species or genus but not on plant status (i.e., exotic vs native). Thus, aboveground herbivory did not promote the dominance of exotic plant species during early establishment of the phylogenetically balanced plant communities
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