15 research outputs found
Energy Saving in Bluetooth 4.0 Wireless Locks Connected via Mobile Phone to the Internet
No full textIn a modern environment users are more dependant on their ability to use their mobile phone for nearly everything. They communicate with almost any device and those devices provide nearly limitless access to for instance a watch or in new applications, a lock. Issues encountered with these devices are the almost always lack the ability to keep functioning for extended periods of time while having high transfer speeds and not a lot of space to store batteries. We present a means to keep a device operating for years with high transfer speeds in Bluetooth low energy connections, while functioning for year on end while connecting to a smartphone for access to the internet. To keep the solution working, high transfer speeds and minimal delays are needed as people are not willing to wait for extensive periods for a lock to open. This has to be done while operating for years with minimal space requirements. Our design uses the the Bluetooth low energy (LE) specification to keep the device connected to the mobile phone. The phone is connected to both the device (a lock) via Bluetooth LE and the internet. While the Bluetooth LE specification is low power, it is still considerably wasteful if high transfer speeds are used. As the internet connections of mobile phones are still considerably slow (even HSDPA) in response time, we can use this in our advantage to save power. The delays in these connections can be used to put the device to sleep. We also maintain full compatibility with the Bluetooth LE standard and keep high transfer speed when needed. Our solution provides the best transfer speed combined with the lower power consumption of low transfer rates. This is done by dynamically throttling the delays between each radio wakeup event. The method is tested for different delays expected in connection types like GPRS, UMTS and HSDPA. As a result device is able to operate for over 35% longer and save 144% power per message exchange without significant additional delays and without compromising the Bluetooth specification. It is also possible to use the technique without any low level access to the link layer which is preferable since it is not always possible to get access to the Bluetooth stack.Embedded SystemsEmbedded SoftwareElectrical Engineering, Mathematics and Computer Scienc
Glados, a secure access control system
No full textWe have created a Secure Access Control System, named Glados. The goal of this system is to limit the access to a building, and separate 'zones' in that building, to authorized persons only. Our primary concerns were security and maintainability. Special care has been taken in identifying possible attack vectors and defending against those. This includes using high-end authentication chips, encryption of communication and centralizing sensitive data. Maintainability was achieved through test-driven development and a modular design.Software EngineeringElectrical Engineering, Mathematics and Computer Scienc
The Crystal Growth and Characterization of CeT2Si2 Ternary Intermetallics (T = Ni, Pd, Pt)
No full textBulk single crystals of the ternary intermetallic compounds CeNi2Si2, CePd2Si2 and CePt2Si2 have been grown from the melt with a modified “tri-arc” Czochralski method. The as-grown crystals were characterized by X-ray, microprobe, and chemical analyses. The measured densities were compared with the calculated densities as obtained from the lattice parameters. In all as-grown single crystals no detectable precipitates of foreign phases were observed. These precipitates are always present in polycrystalline samples, even after a heat-treatment, and are visible on the grain boundaries and in the subgrain structure.
Crystal Growth and Characterization of MT2Si2 Ternary Intermetallics (M = U, RE and T = 3d, 4d, 5d Transition Metals)
No full textBulk single crystals of the ternary intermetallic compounds UT2Si2 (T = Ni, Pd, Pt and Ru), LaT2Si2 (T = Pd and Rh) and LuPd2Si2 have been grown from the melt with a modified “tri-arc” Czochralski method. The as-grown crystals were characterized by X-ray, microprobe and chemical analyses. The measured densities are compared with the calculated densities as obtained from the lattice parameters. A detailed metallography analysis of both polycrystalline and single-crystalline samples shows that the Mt2Si2 intermetallics exist only in a very narrow homogeneity range and that the segregation of second phase is almost always present in polycrystalline samples and can severely mask the intrinsic properties of these materials. The effect of heat treatment on the electrical resistivity of single-crystalline URu2Si2 is presented, alone with some preliminary results on the crystal growth of URh2Ge2.
Spin-Hall magnetoresistance and spin Seebeck effect in spin-spiral and paramagnetic phases of multiferroic CoCr2O4 films
No full textWe report on the spin-Hall magnetoresistance (SMR) and spin Seebeck effect (SSE) in multiferroic CoCr2O4 (CCO) spinel thin films with Pt contacts. We observe a large enhancement of both signals below the spin-spiral (Ts=28K) and the spin lock-in (Tlock?in=14K) transitions. The SMR and SSE responses in the spin lock-in phase are one order of magnitude larger than those observed at the ferrimagnetic transition temperature (Tc=94K), which indicates that the interaction between spins at the Pt|CCO interface is more efficient in the noncollinear magnetic state. At T>Tc, magnetic-field-induced SMR and SSE signals are observed, which can be explained by a high interface susceptibility. Our results show that the spin transport at the Pt|CCO interface is sensitive to the magnetic phases but cannot be explained solely by the bulk magnetization.QN/Quantum NanoscienceApplied Science
Phase diagram and magnetic relaxation phenomena in Cu2OSeO3
No full textWe present an investigation of the magnetic-field-temperature phase diagram of Cu2OSeO3 based on dc magnetization and ac susceptibility measurements covering a broad frequency range of four orders of magnitude, from very low frequencies reaching 0.1 Hz up to 1 kHz. The experiments were performed in the vicinity of Tc=58.2 K and around the skyrmion lattice A phase. At the borders between the different phases the characteristic relaxation times reach several milliseconds and the relaxation is nonexponential. Consequently the borders between the different phases depend on the specific criteria and frequency used and an unambiguous determination is not possible.</p
Robust estimation of cortical similarity networks from brain MRI
No full text© 2023, The Author(s). Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.Structural similarity is a growing focus for magnetic resonance imaging (MRI) of connectomes. Here we propose Morphometric INverse Divergence (MIND), a new method to estimate within-subject similarity between cortical areas based on the divergence between their multivariate distributions of multiple MRI features. Compared to the prior approach of morphometric similarity networks (MSNs) on n > 11,000 scans spanning three human datasets and one macaque dataset, MIND networks were more reliable, more consistent with cortical cytoarchitectonics and symmetry and more correlated with tract-tracing measures of axonal connectivity. MIND networks derived from human T1-weighted MRI were more sensitive to age-related changes than MSNs or networks derived by tractography of diffusion-weighted MRI. Gene co-expression between cortical areas was more strongly coupled to MIND networks than to MSNs or tractography. MIND network phenotypes were also more heritable, especially edges between structurally differentiated areas. MIND network analysis provides a biologically validated lens for cortical connectomics using readily available MRI data.I.S. was generously supported by a Gates-Cambridge Scholarship and by the Accelerate Programme for Scientific Discovery, funded by Schmidt Futures. J.S. was supported by National Institute of Mental Health (NIMH) grant T32MH019112. A.A.B. and J.S. were supported by NIMH grant K08MH120564. V.W. was supported by St. Catharine’s College Cambridge. R.A.I.B. was supported by the Autism Research Trust. R.R.G. is funded by the EMERGIA Junta de Andalucía program (EMERGIA20_00139) and the Plan Propio of the University of Seville. T.T.M. was supported by National Institutes of Health (NIH) grant T32HG010464. E.T.B. was supported by a National Institute for Health and Care Research (NIHR) Senior Investigator award. S.E.M. was supported by the Accelerate Programme for Scientific Discovery, funded by Schmidt Futures, and a fellowship from the Alan Turing Institute, London (EPSRC grant EP/N510129/1).Peer reviewe
Entrepreneurial orientation and the franchise system: organisational antecedents and performance outcomes
No full textThe purpose of this paper is to understand the franchisor's perception of the role of entrepreneurial strategic orientation (EO)-innovative, risk-taking, and proactive actions-within the special case of franchised firms, given the opposing forces for standardisation/uniformity and system innovation/adaptation. A cross-sectional research design, involving a mail questionnaire survey, was employed to collect data from a sample of franchisors operating in the UK. The hypotheses specified in the study were tested using regression (including moderated regression) analyses. The results revealed that EO was significantly and positively related to the performance outcomes of franchise systems, both from financial and non-financial perspectives. In addition, both franchisor support and franchise contract clauses were positively and significantly related to EO. The external contexts of the franchise system-environmental hostility and environmental dynamism-were not found to be significant moderators in the relationship between EO and performance outcomes. This study extends our knowledge of the EO-performance outcomes relationship to the franchising context where the role of EO is presently underexplored
Entrepreneurial orientation and the franchise system: organisational antecedents and performance outcomes
No full textPurpose – The purpose of this paper is to understand the franchisor's perception of the role of entrepreneurial strategic orientation (EO) – innovative, risk-taking, and proactive actions – within the special case of franchised firms, given the opposing forces for standardisation/uniformity and system innovation/adaptation.
Design/methodology/approach – A cross-sectional research design, involving a mail questionnaire survey, was employed to collect data from a sample of franchisors operating in the UK. The hypotheses specified in the study were tested using a path model.
Findings – The results show that for franchise organisations, EO is positively related to performance. The recent meta-analysis conducted by Rauch et al. also demonstrated that the correlation of EO with performance is fairly large (r=0.242). This correlation is consistent with the significant value reported in the study of 0.234. In addition, franchise system support structures were found to be important in fostering EO within the organisation.
Research limitations/implications – Future studies may consider including other dimensions of EO, notably competitive aggressiveness and autonomy, in exploring the relevance of EO to the franchise system. It would be interesting to also use a longitudinal analysis to examine the long-term effect of EO on the performance of franchised firms.
Originality/value – The study extends knowledge of the EO-performance outcomes relationship to the franchising context where the role of EO is presently under-explored. This could be attributed to the fact that the franchise concept is built on standardisation and uniformity, notions that run counter to the flexible strategies involved in fostering EO
Distribution of Epstein-Barr virus antigenic sites on the carboxyl terminal end of ribonucleotide reductase against nasopharyngeal carcinoma serum antibodies using an immunoabsorption method
No full text10.1002/(SICI)1096-9071(199911)59:33.0.CO;2-7Journal of Medical Virology593385-396JMVI
