jxSensor: a sensor network integration layer for JXTA

Nowadays, Wireless Sensor Networks (WSN) arealready a very important data source to obtain data about the environment. Thus, they are key to the creation of Cyber-Physical Systems (CPS). Given the popularity of P2P middlewares as ameans to efficiently process information and distribute services, being able to integrate them to WSN¿s is an interesting proposal. JXTA is a widely used P2P middleware that allows peers to easily exchange information, heavily relying on its main architectural highlight, the capability to organize peers with common interests into peer groups. However, right now, approaches to integrate WSNs to a JXTA network seldom take advantage of peer groups. For this reason, in this paper we present jxSensor, an integrationlayer for sensor motes which facilitates the deployment of CPS¿s under this architecture. This integration has been done taking into account JXTA¿s idiosyncrasies and proposing novel ideas,such as the Virtual Peer, a group of sensors that acts as a single entity within the peer group context.

A Social Network Analysis of Twitter: Mapping the Digital Humanities Community

Defining digital humanities might be an endless debate if we stick to the discussion about the boundaries of this concept as an academic "discipline". In an attempt to concretely identify this field and its actors, this paper shows that it is possible to analyse them through Twitter, a social media widely used by this "community of practice". Based on a network analysis of 2,500 users identified as members of this movement, the visualisation of the "who's following who?" graph allows us to highlight the structure of the network's relationships, and identify users whose position is particular. Specifically, we show that linguistic groups are key factors to explain clustering within a network whose characteristics look similar to a small world.

Towards a Network Government? A critical analysis of current assessment methods for e-Government

Contemporary public administrations have become increasingly more complex, having to cordinate actions with emerging actors in the public and the private spheres. In this scenario the modern ICTs have begun to be seen as an ideal vehicle to resolve some of the problems of public administration. We argue that there is a clear need to explore the extent to which public administrations are undergoing a process of transformation towards a netowork government linked to the systematic incorporation of ICTs in their basic activities. Through critically analysing a selection of e-government evaluation reports, we conclude that research should be carried out if we are to build a solid government assessment framework based on network-like organisation characteristics.

Creating a research network for a successful e-portfolio design and implementation

The presence of e-portfolios in educational centres, companies and administrations has emergedstrongly during the last years by creating very different practices coming from different objectives and purposes. This situation has led researchers and practitioners to design and implement e-portfolios with little reference to previous knowledge of them; consequently, developments are disparate with many of the processes and dimensions used both in development and use being unnecessary complex. In order to minimize the inconveniences, unify these developmental processes and improve the resultsof implementation and use of e-portfolios, it seemed necessary to create a network of researchers, teachers and trainers coming from different universities and institutions of different kinds who are interested in the investigation and the practice of e-portfolios in Spain. Therefore, The Network on e-portfoliowas created in 2006, funded by the Spanish Ministry of Education and led by the UniversitatOberta de Catalunya. Besides the goals associatedwith the creation of this network and which wewanted to share with other European researchers and experts of other continents, we will also present in this paper some data concerned with the first study carried out on the use of e-portfolios in our country that shows where we are and which trends are the most important for the near future.

The practical application of e-Portfolio at the Open University of Catalonia : assessment of competence based learning

The paper presents the results of the piloting or pilot test in a virtual classroom. This e-portfolio was carried out in the 2005-2006 academic year, with students of the Doctorate in Information Society, at the Open University of Catalonia. The electronic portfolio is a strategy for competence based assessment. This experience shows the types of e-portfolios, where students show their work without interactions, and apply the competence-based learning theories in an interactive portfolio system. The real process of learning is developed in the competency based system, the portfolio not only is a basic bio document, has become a real space for learning with competence model. The paper brings out new ideas and possibilities: the competence-based learning promotes closer relationships between universities and companies and redesigns the pedagogic act.

Complete Analysis of Configuration Rules to Guarantee Reliable Network Security Policies

Peer-reviewed

Aggregating and Deploying Network Access Control Policies

Peer-reviewed

An Experimental Study on Peer Selection in a P2P Network over PlanetLab

Peer-reviewed

Authentication and authorization service for a community network

Wireless community networks became popular in uniting people with common interests. This thesis presents authentication and authorization service for a wireless community network using captive portal approach including ability to authenticate clients from associated networks thereby combining multiple communities in a syndicate. The system is designed and implemented to be reliable, scalable and flexible. Moreover, the result includes software management system, which automatically performs software updates at network’s access points. Future development of the system can be concentrated on an improvement of the software management system.

Pienvesivoiman elvytys, käyttöönotto ja kannattavuus

Uusiutuvan energian tuottamisen lisääminen on edellytys saavuttaaksemme EU:n asettamat tavoitteet. Tämän takia on syytä tutkia kaikki mahdollisuudet uusiutuvan energian tuottamisen lisäämiseksi jopa aivan pienimmistä laitoksista lähtien. Tämän työn tarkoituksena on tutkia pienvesivoiman taloudellisuutta ja kannattavuutta energiantuotannossa. Työssä suoritetaan myös kustannuslaskenta, jossa pohditaan käytöstä poistetun laitoksen palauttamista takaisin sähkön tuotantoon. Samalla käydään läpi teknisiä, taloudellisia ja lakisääteisiä kysymyksiä, joita pienvoiman verkkoonliittäminen aiheuttaa. Tämä työ on eräänlainen käsikirja pienvesivoimasta. Pienvesivoiman liittäminen jakeluverkkoon on sinällään suojausteknisesti yksinkertaista, mutta kaikkien eri taloudellisten ja lakiteknisten tekijöiden huomioonottaminen on puolestaan haastavaa. Laitosten käyttö ja kunnossapito eivät sinällään vaadi sähköteknistä osaamista, kunhan turvallisuusseikat otetaan visusti huomioon. Työssä havaittiin, että pienvesivoima ei pienissä laitoksissa riitä kattamaan suuria työvoimakustannuksia, joita syntyy, kun yritysten henkilökunta ottaa osaa laitoksen toimintaan. Toisaalta pienvesivoima on erinomainen tapa tuottaa sähköä yksityiselle ihmiselle, mikäli hän on itse valmis operoimaan laitosta eikä laske omalle työlleen suuria kustannuksia. Edellytyksenä on, että omalta maa‐alueelta löytyy pienikin puro suhteellisen läheltä jakeluverkkoa.

Competence Development and Capacity Building of Sawmill Enterprises in Kenya – A Human Resources Development Approach

The Kenyan forestry and sawmilling industry have been subject to a changing environment since 1999 when the industrial forest plantations were closed down. This has lowered raw material supply and it has affected and reduced the sawmill operations and the viability of the sawmill enterprises. The capacity of the 276 registered sawmills is not sufficient to fulfill sawn timber demand in Kenya. This is because of the technological degradation and lack of a qualified labor force, which were caused because of non-existent sawmilling education and further training in Kenya. Lack of competent sawmill workers has led to low raw material recovery, under utilization of resources and loss of employment. The objective of the work was to suggest models, methods and approaches for the competence and capacity development of the Kenyan sawmilling industry, sawmills and their workers. A nationwide field survey, interviews, questionnaire and literature review was used for data collection to find out the sawmills’ competence development areas and to suggest models and methods for their capacity building. The sampling frame included 22 sawmills that represented 72,5% of all the registered sawmills in Kenya. The results confirmed that the sawmills’ technological level was backwards, productivity low, raw material recovery unacceptable and workers’ professional education low. The future challenges will be how to establish the sawmills’ capacity building and workers’ competence development. Sawmilling industry development requires various actions through new development models and approaches. Activities should be started for technological development and workers’ competence development. This requires re-starting of vocational training in sawmilling and the establishment of more effective co-operation between the sawmills and their stakeholder groups. In competence development the Enterprise Competence Management Model of Nurminen (2007) can be used, whereas the best training model and approach would be a practically oriented learning at work model in which the short courses, technical assistance and extension services would be the key functions.

Wide Area Network Acceleration in Corporate Networks

There are several factors affecting network performance. Some of these can be controlled whereas the others are more fixed. These factors are studied in this thesis from the wide area network (WAN) perspective and the focus is on corporate networks. Another area of interest is the behavior of application protocols when used through WAN. The aim is to study the performance of commonly used application protocols in corporate networks. After identifying the performance problems in corporate WANs the thesis concentrates on methods for improving WAN performance. WAN acceleration is presented as a possible solution. The different acceleration methods are discussed in order to give the reader a theoretical view on how the accelerators can improve WAN performance. Guidelines on the installation of accelerators into a network are also discussed. After a general overview on accelerators is given, one accelerator vendor currently on market is selected for a further analysis. The work is also a case study where two accelerators are installed into a target company network for testing purposes. The tests are performed with three different application protocols that have been identified as critical applications for the target corporation. The aim of the tests is to serve as a proof of concept for WAN acceleration in the target network.

The temporal dynamics of resource use by frugivorous birds: a network approach

Ecological network patterns are influenced by diverse processes that operate at different temporal rates. Here we analyzed whether the coupled effect of local abundance variation, seasonally phenotypic plastic responses, and species evolutionary adaptations might act in concert to shape network patterns. We studied the temporal variation in three interaction properties of bird species (number of interactions per species, interaction strength, and interaction asymmetry) in a temporal sequence of 28 plant frugivore interaction networks spanning two years in a Mediterranean shrubland community. Three main hypotheses dealing with the temporal variation of network properties were tested, examining the effects of abundance, switching behavior between alternative food resources, and morphological traits in determining consumer interaction patterns. Our results demonstrate that temporal variation in consumer interaction patterns is explained by short-term variation in resource and bird abundances and seasonal dietary switches between alternative resources (fleshy fruits and insects). Moreover, differences in beak morphology are associated with differences in switching behavior between resources, suggesting an important role of foraging adaptations in determining network patterns. We argue that beak shape adaptations might determine generalist and specialist feeding behaviors and thus the positions of consumer species within the network. Finally, we provide a preliminary framework to interpret phylogenetic signal in plant animal networks. Indeed, we show that the strength of the phylogenetic signal in networks depends on the relative importance of abundance, behavioral, and morphological variables. We show that these variables strongly differ in their phylogenetic signal. Consequently, we suggest that moderate and significant phylogenetic effects should be commonly observed in networks of species interactions. Read More: http://www.esajournals.org/doi/abs/10.1890/07-1939.1

The maximum voltage drop in an on-chip power distribution network: analysis of square, triangular and hexagonal power pad arrangements

A mathematical model of the voltage drop which arises in on-chip power distribution networks is used to compare the maximum voltage drop in the case of different geometric arrangements of the pads supplying power to the chip. These include the square or Manhattan power pad arrangement, which currently predominates, as well as equilateral triangular and hexagonal arrangements. In agreement with the findings in the literature and with physical and SPICE models, the equilateral triangular power pad arrangement is found to minimize the maximum voltage drop. This headline finding is a consequence of relatively simple formulas for the voltage drop, with explicit error bounds, which are established using complex analysis techniques, and elliptic functions in particular.

DWI and complex brain network analysis predicts vascular cognitive impairment in spontaneous hypertensive rats undergoing executive function tests

The identification of biomarkers of vascular cognitive impairment is urgent for its early diagnosis. The aim of this study was to detect and monitor changes in brain structure and connectivity, and to correlate them with the decline in executive function. We examined the feasibility of early diagnostic magnetic resonance imaging (MRI) to predict cognitive impairment before onset in an animal model of chronic hypertension: Spontaneously Hypertensive Rats. Cognitive performance was tested in an operant conditioning paradigm that evaluated learning, memory, and behavioral flexibility skills. Behavioral tests were coupled with longitudinal diffusion weighted imaging acquired with 126 diffusion gradient directions and 0.3 mm(3) isometric resolution at 10, 14, 18, 22, 26, and 40 weeks after birth. Diffusion weighted imaging was analyzed in two different ways, by regional characterization of diffusion tensor imaging (DTI) indices, and by assessing changes in structural brain network organization based on Q-Ball tractography. Already at the first evaluated times, DTI scalar maps revealed significant differences in many regions, suggesting loss of integrity in white and gray matter of spontaneously hypertensive rats when compared to normotensive control rats. In addition, graph theory analysis of the structural brain network demonstrated a significant decrease of hierarchical modularity, global and local efficacy, with predictive value as shown by regional three-fold cross validation study. Moreover, these decreases were significantly correlated with the behavioral performance deficits observed at subsequent time points, suggesting that the diffusion weighted imaging and connectivity studies can unravel neuroimaging alterations even overt signs of cognitive impairment become apparent.