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Energy-efficient node selection in application-driven WSN
Get PDFThe growth of wireless networks has resulted in part from requirements for connecting people and advances in radio technologies. Wireless sensor networks are an example of these networks in which a large number of tiny devices interacting with their environments may be internet-worked together and accessible through the Internet. As these devices may be scattered in an unplanned way, a routing protocol is needed. The RPL protocol is the IETF proposed standard protocol for IPv6-based multi-hop WSN. RPL requires that communication paths go through a central router which may provide suboptimal paths, not considering the characteristics of the applications the nodes run. In this paper is proposed an Application-Driven extension to RPL which enables to increase the WSN lifetime by limiting the routing and forwarding functions of the network mainly to nodes running the same application. As nodes may join a network at a non predictable time, they must be synchronized with respect to their application duty cycles. Therefore, nodes have to wake up and sleep in a synchronized way. In this paper it is also proposed such synchronization mechanism. The results confirm that the proposed solutions provide lower energy consumption and lower number of packets exchanged than the conventional RPL solution, while maintaining fairness and the packet reception ratio high
Real-Time Optical Monitoring of Etching Reaction of Microfluidic Channel Fabricated by Femtosecond Laser Direct Writing
Get PDFFemtosecond laser direct writing is a three dimensional fabrication technique that can be applied to produce integrated optical components with high spatial resolution or microfluidic channels when combined with HF etching. The same fabrication technique can thus be employed to produce monolithic optofluidic devices for sensing applications. One of the most common sensing schemes involves evanescent optical interaction; therefore, the channel must meet some requirements regarding surface roughness, which will depend on the laser writing conditions, as described in this paper. However, of more significance is the distance between waveguiding medium and microfluidic channel that must be accurately defined. This control can be achieved by monitoring the etching reaction of a waveguide grating written a few microns from the channel, as introduced in this paper. In addition to its function as an etching monitor, the grating can also be used as a coarse refractive index sensor device
Institutional networks for supporting the internationalisation of SMEs: the case of industrial business associations
Get PDFPurpose - This paper aims to study and explore the activities and the use of institutional network resources by industrial business associations (IBAs) to support and facilitate internationalisation processes of small-and medium-sized enterprises (SMEs). Other goals are to understand the internationalisation follow-up process and the future vision of IBAs to improve this internationalisation support. Design/methodology/approach - Based on empirical evidence and following an abductive approach, this paper presents a qualitative exploratory field research, providing insights from interviews performed with 20 IBAs based in Portugal. Findings - The findings suggest that the current institutional network support to internationalisation is mainly provided through promotional activities; counselling, training and technical and legal support; information sharing; and cooperation with other institutional entities. Each support category is explored and explained and a new conceptual model is developed to represent these findings. Regarding the internationalisation follow-up, IBAs provide a continuous support for the international operations by using some instruments and mechanisms to assist SMEs after an internationalisation initiative. Finally, collaboration and the use of new information technology are the main aspects to improve IBAs' support in a near future. Research limitations/implications - The qualitative methodological approach adopted in this work can imply a larger difficulty to obtain a generalisation of the findings. Another limitation is that the participating IBAs are based in only one country. Practical implications - Findings can help SMEs to understand the functioning and the benefits of using the institutional network resources of IBAs in overcoming their lack of resources to operate in international markets. IBAs can also understand their current position in terms of internationalisation support and think about new ways for improving this support. Originality/value - This paper contributes to a better understanding of the influence of institutional networks in SME internationalisation by exploring the specific role of one of the institutional actors rather than focusing on the institutional network as a whole. Therefore, this study details the current activities and uncovers other types of support provided by IBAs that are not based on export promotion programmes. New knowledge is also obtained about the specific information content, information sources and means and channels of information sharing used by IBAs for supporting SME internationalisation
Effects of Language and Terminology of Query Suggestions on Medical Accuracy Considering Different User Characteristics
Get PDFSearching for health information is one of the most popular activities on the web. In this domain, users often misspell or lack knowledge of the proper medical terms to use in queries. To overcome these difficulties and attempt to retrieve higher-quality content, we developed a query suggestion system that provides alternative queries combining the Portuguese or English language with lay or medico-scientific terminology. Here we evaluate this system's impact on the medical accuracy of the knowledge acquired during the search. Evaluation shows that simply providing these suggestions contributes to reduce the quantity of incorrect content. This indicates that even when suggestions are not clicked, they are useful either for subsequent queries' formulation or for interpreting search results. Clicking on suggestions, regardless of type, leads to answers with more correct content. An analysis by type of suggestion and user characteristics showed that the benefits of certain languages and terminologies are more perceptible in users with certain levels of English proficiency and health literacy. This suggests a personalization of this suggestion system toward these characteristics. Overall, the effect of language is more preponderant than the effect of terminology. Clicks on English suggestions are clearly preferable to clicks on Portuguese ones
Predicting the Relevance of Social Media Posts Based on Linguistic Features and Journalistic Criteria
Get PDFAn overwhelming quantity of messages is posted in social networks every minute. To make the utilization of these platforms more productive, it is imperative to filter out information that is irrelevant to the general audience, such as private messages, personal opinions or well-known facts. This work is focused on the automatic classification of public social text according to its potential relevance, from a journalistic point of view, hopefully improving the overall experience of using a social network. Our experiments were based on a set of posts with several criteria, including the journalistic relevance, assessed by human judges. To predict the latter, we rely exclusively on linguistic features, extracted by Natural Language Processing tools, regardless the author of the message and its profile information. In our first approach, different classifiers and feature engineering methods were used to predict relevance directly from the selected features. In a second approach, relevance was predicted indirectly, based on an ensemble of classifiers for other key criteria when defining relevance-controversy, interestingness, meaningfulness, novelty, reliability and scope-also in the dataset. The first approach achieved a F (1)-score of 0.76 and an Area under the ROC curve (AUC) of 0.63. But the best results were achieved by the second approach, with the best learned model achieving a F (1)-score of 0.84 with an AUC of 0.78. This confirmed that journalistic relevance can indeed be predicted by the combination of the selected criteria, and that linguistic features can be exploited to classify the latter
3D Tendon Strain Estimation Using High-frequency Volumetric Ultrasound Images: A Feasibility Study
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