An empirical Kaiser criterion

In exploratory factor analysis (EFA), most popular methods for dimensionality assessment such as the screeplot, the Kaiser criterion, or—the current gold standard—parallel analysis, are based on eigenvalues of the correlation matrix. To further understanding and development of factor retention methods, results on population and sample eigenvalue distributions are introduced based on random matrix theory and Monte Carlo simulations. These results are used to develop a new factor retention method, the Empirical Kaiser Criterion. The performance of the Empirical Kaiser Criterion and parallel analysis is examined in typical research settings, with multiple scales that are desired to be relatively short, but still reliable. Theoretical and simulation results illustrate that the new Empirical Kaiser Criterion performs as well as parallel analysis in typical research settings with uncorrelated scales, but much better when scales are both correlated and short. We conclude that the Empirical Kaiser Criterion is a powerful and promising factor retention method, because it is based on distribution theory of eigenvalues, shows good performance, is easily visualized and computed, and is useful for power analysis and sample size planning for EF

Factor copula models for item response data

Factor or conditional independence models based on copulas are proposed for multivariate discrete data such as item responses. The factor copula models have interpretations of latent maxima/minima (in comparison with latent means) and can lead to more probability in the joint upper or lower tail compared with factor models based on the discretized multivariate normal distribution (or multidimensional normal ogive model). Details on maximum likelihood estimation of parameters for the factor copula model are given, as well as analysis of the behavior of the log-likelihood. Our general methodology is illustrated with several item response data sets, and it is shown that there is a substantial improvement on existing models both conceptually and in fit to data

Enhanced end-to-end security through symmetric-key cryptography in wearable medical sensor networks

Computer Science

3D Microstructured Carbon Nanotube Electrodes for Trapping and Recording Electrogenic Cells

Electrogenic cells such as cardiomyocytes and neurons rely mainly on electrical signals for intercellular communication. Microelectrode arrays (MEAs) have been developed for long-term recording of cell signals and stimulation of electrogenic cells under low-cell-stress conditions, providing new insights in the behavior of electrogenic cells and the operation of the brain. To date, MEAs are relying on flat or needle-shaped electrode surfaces, mainly due to limitations in the lithographic processes. This paper relies on a previously reported elasto-capillary aggregation process to create 3D carbon nanotube (CNT) MEAs. This study shows that CNTs aggregate in well-shaped structures of similar size as cardiomyocytes are particularly interesting for MEA applications. This is because i) CNT microwells of the right diameter preferentially trap individual cardiomyocytes, which facilitates single cell recording without the need for clamping cells or signal deconvolution, and ii) once the cells are trapped inside of the CNT wells, this 3D CNT structure is used as an electrode surrounding the cell, which increases the cell-electrode contact area. As a result, this study finds that the recorded output voltages increase significantly (more than 200%). This fabrication process paves the way for future study of complex interactions between electrogenic cells and 3D recording electrodes.This work was supported by the Research Foundation—Flanders (FWO, Belgium) under Project No. 11S1214N. Michael De Volder was supported by the ERC Starting Grant (337739)—HIENA and the Marie Curie Grant CANA (618250). Davor Copic was supported by the Marie Curie Grant EmuCam (660351)

In-depth energy analysis of security algorithms and protocols for the Internet of Things

Computer Science

The development and validation of a five-factor model of Sources of Self-Efficacy in clinical nursing education

Background: The aim of this study is to validate a newly developed nurses' self-efficacy sources inventory. We test the validity of a five-dimensional model of sources of self-efficacy, which we contrast with the traditional four-dimensional model based on Bandura’s theoretical concepts.Methods: Confirmatory factor analysis was used in the development of the newly developed self-efficacy measure. Model fit was evaluated based upon commonly recommended goodness-of-fit indices, including the χ2 of the model fit, the Root Mean Square Error of approximation (RMSEA), the Tucker-Lewis Index (TLI), the Standardized Root Mean Square Residual (SRMR), and the Bayesian Information Criterion (BIC).Results: All 22 items of the newly developed five-factor sources of self-efficacy have high factor loadings (range .40-.80). Structural equation modeling showed that a five-factor model is favoured over the four-factor model.Conclusions and implications: Results of this study show that differentiation of the vicarious experience source into a peer- and expert based source reflects better how nursing students develop self-efficacy beliefs. This has implications for clinical learning environments: a better and differentiated use of self-efficacy sources can stimulate the professional development of nursing students

Anonymous Secure Framework in Connected Smart Home Environments

The smart home is an environment where heterogeneous electronic devices and appliances are networked together to provide smart services in an ubiquitous manner to the individuals. As the homes become smarter, more complex and technology dependent, the need for an adequate security mechanism with minimum individual’s intervention is growing. The recent serious security attacks have shown how the Internetenabled smart homes can be turned into very dangerous spots for various ill intentions, and thus lead the privacy concerns for the individuals. For instance, an eavesdropper is able to derive the identity of a particular device/appliance via public channels that can be used to infer in the life pattern of an individual within the home area network. This paper proposes an anonymous secure framework (ASF) in connected smart home environments, using solely lightweight operations. The proposed framework in this paper provides efficient authentication and key agreement, and enables devices (identity and data) anonymity and unlinkability. One-time session key progression regularly renews the session key for the smart devices and dilutes the risk of using a compromised session key in the ASF. It is demonstrated that computation complexity of the proposed framework is low as compared to the existing schemes, while security has been significantly improved

A Smart Bluetooth-based Ad Hoc Management System for Appliances in Home Environments

The number of home devices integrating new technologies is continuously increasing. These advances allow us to improve our daily routines. In addition, the improvement in network infrastructure and the development of smart phones and mobile devices allow us access from any place to any of our systems over the Internet. Bearing in mind this idea, we have developed a low-cost ad hoc protocol based on Bluetooth technology that allows us to control all our home appliances and monitor the power consumption of our homes. Our proposal is based on an Android application installed on a mobile device which acts as server. The application allows users to program the various appliances. It is also able to check the status of the appliance, as well as controlling the power consumption of the house and its cost. The system is equipped with a smart algorithm able to manage all appliances and decide which ones should work as a function of various criteria such as time of day or power consumption. Finally, the system is able to detect faults in water and electricity supply for acting accordingly. All data received and sent by the server are stored in a database which the system can check and compare to make their own decisions.Sendra, S.; Laborda, A.; Díaz Santos, JR.; Lloret, J. (2015). A Smart Bluetooth-based Ad Hoc Management System for Appliances in Home Environments. Springer Verlag (Germany): LNCS. 8487:128-141. doi:10.1007/978-3-319-07425-2_10S1281418487Garcia, M., Sendra, S., Lloret, J., Canovas, A.: Saving energy and improving communications using cooperative group-based Wireless Sensor Networks. Telecommunication Systems 52(4), 2489–2502 (2013)Liu, Y., Zhou, G.: Technologies and Applications of Internet of Things. In: Proceedings of 2012 Fifth International Conference on Intelligent Computation Technology and Automation (ICICTA), Zhangjiajie, China, January 12-14, pp. 197–200 (2012)Aiello, M.: The Role of Web Services at Home. In: Proceedings of the Advanced International Conference on Telecommunications and International Conference on Internet and Web Applications and Services (AICT-ICIW 2006), Guadeloupe, France, February 23-25 (2006)Mowafi, M.Y., Awad, F.H., Al-Batati, M.A.: Opportunistic Network Coding for Real-Time Transmission over Wireless Networks. Network Protocols and Algorithms 5(1), 1–19 (2013)Gangadhar, G., Nayak, S., Puttamadappa, C.: Intelligent Refrigerator with monitoring capability through internet. International Journal of Computer Applications. Special Issue on “Wireless Information Networks & Business Information System 2(7), 65–68 (2011)Soucek, S., Russ, G., Tamarit, C.: The Smart Kitchen Project—An Application of Fieldbus Technology to Domotics. In: Proceedings of 2nd International Workshop on Networked Appliances (IWNA 2000), New Brunswick, NJ, USA, November 30-December 1 (2000)Zhang, W., Tan, G.-Z., Ding, N.: Traffic Information Detection Based on Scattered Sensor Data: Model and Algorithms. Adhoc & Sensor Wireless Networks 18(3-4), 225–240 (2013)Ranjit, J.S., Shin, S.: A Modified IEEE 802.15. 4 Superframe Structure for Guaranteed Emergency Handling in Wireless Body Area Network. Network Protocols & Algorithms 5(2), 1–15 (2013)Braeken, A., Singelee, D.: Efficient and Location-Private Communication Protocols for WBSNs. Adhoc & Sensor Wireless Networks 19(3-4), 305–326 (2013)Augusto, J.C., McCullagh, P., McClelland, V., Walkden, J.A.: Enhanced healthcare provision through assisted decision-making in a smart home environment. In: Proceedings of the Second Workshop on Artificial Intelligence Techniques for Ambient Intelligence (AITAmI 2007), Hyderabad, India, January 6-7 (2007)Zhang, L., Zhao, Z., Li, D., Liu, Q., Cui, L.: Wildlife Monitoring Using Heterogeneous Wireless Communication Network. Adhoc & Sensor Wireless Networks 18(3-4), 159–179 (2013)Viani, F., Robol, F., Polo, A., Rocca, P., Oliveri, G., Massa, A.: Wireless Architectures for Heterogeneous Sensing in Smart Home Applications: Concepts and Real Implementation. Proceedings of the IEEE 101(11), 2381–2396 (2013)Lloret, J., Macías, E., Suárez, A., Lacuesta, R.: Ubiquitous Monitoring of Electrical Household Appliances. Sensors 12(11), 15159–15191 (2012)Kamilaris, A., Trifa, V., Pitsillides, A.: The smart home meets the Web of Things. International Journal of Ad Hoc and Ubiquitous Computing 7(3), 145–154 (2011)Kamilaris, A., Trifa, V., Pitsillides, A.: An Application Framework for Web-Based Smart Homes. In: Proceedings of the 18th International Conference on Telecommunications, ICT 2011, Ayia Napa, Cyprus, May 8-11, pp. 134–139 (2011)IEEE Std 802.15.1-2002 – IEEE Standard for Information technology – Telecommunications and information exchange between systems – Local and metropolitan area networks – Specific requirements Part 15.1: Wireless Medium Access Control (MAC) and Physical Layer (PHY) Specifications for Wireless Personal Area Networks (WPANs)KNX international Site, http://www.knx.org/knx-en/index.php (last access: February 1, 2014)LonWorks Technology. In: ECHELON web site, http://www.echelon.com/technology/lonworks/ (last access: February 1, 2014)X10 protocol. In: X10 web site, http://x10-lang.org/ (last access: February 1, 2014)Rohini Basak, R., Sardar, B.: Security in Network Mobility (NEMO): Issues, Solutions, Classification, Evaluation, and Future Research Directions. Network Protocols and Algorithms 5(2), 87–111 (2013

The usefulness and feasibility of a screening instrument to identify psychosocial problems in patients receiving curative radiotherapy: a process evaluation

<p>Abstract</p> <p>Background</p> <p>Psychosocial problems in cancer patients are often unrecognized and untreated due to the low awareness of the existence of these problems or pressures of time. The awareness of the need to identify psychosocial problems in cancer patients is growing and has affected the development of screening instruments. This study explored the usefulness and feasibility of using a screening instrument (SIPP: Screening Inventory of Psychosocial Problems) to identify psychosocial problems in cancer patients receiving curative radiotherapy treatment (RT).</p> <p>Methods</p> <p>The study was conducted in a radiation oncology department in the Netherlands. Several methods were used to document the usefulness and feasibility of the SIPP. Data were collected using self-report questionnaires completed by seven radiotherapists and 268 cancer patients.</p> <p>Results</p> <p>Regarding the screening procedure 33 patients were offered to consult a psychosocial care provider (e.g. social worker, psychologist) during the first consultation with their radiotherapist. Of these patients, 31 patients suffered from at least sub-clinical symptoms and two patients hardly suffered from any symptoms. Patients' acceptance rate 63.6% (21/33) was high. Patients were positive about the content of the SIPP (mean scores vary from 8.00 to 8.88, out of a range between 0 and 10) and about the importance of discussing items of the SIPP with their radiotherapist (mean score = 7.42). Radiotherapists' perspectives about the contribution of the SIPP to discuss the different psychosocial problems were mixed (mean scores varied from 3.17 to 4.67). Patients were more positive about discussing items of the SIPP if the radiotherapists had positive attitudes towards screening and discussing psychosocial problems.</p> <p>Conclusions</p> <p>The screening procedure appeared to be feasible in a radiotherapy department. In general, patients' perspectives were at least moderate. Radiotherapists considered the usefulness and feasibility of the SIPP generally to be lower, but their evaluations were mixed. A positive attitude to using screening instruments like the SIPP needs to be encouraged among radiotherapists, as this may not only improve the usefulness of a screening instrument, but also patients' satisfaction with care.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov: <a href="http://www.clinicaltrials.gov/ct2/show/NCT00859768">NCT00859768</a></p