| 40971. |
- Khelghatdoust, Mansour, et al.
(författare)
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A Socially-Aware, Privacy-Preserving, and Scalable Federated Learning Protocol for Distributed Online Social Networks
- 2022
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Ingår i: Advanced Information Networking and Applications. - Cham : Springer Science+Business Media B.V.. - 9783030995867 - 9783030995874 ; , s. 192-203
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Konferensbidrag (refereegranskat)abstract
- Online Social Networks (OSNs) have been gaining tremendous growth by attracting billions of users from all over the world. Such massive growth leads to scalability and data privacy concerns. Decentralized solutions still are not able to solve privacy and scalability problems efficiently. Hence, recently fully Distributed Online Social Networks (DOSNs) have been proposed. However, despite solving scalability and privacy issues, fully DOSNs impose difficulties in executing data mining and machine learning services which are vital for social networks. In the fully DOSN, each user has only one feature vector and these vectors cannot move to any central storage or other users in a raw form due to privacy issues. In addition, users can directly communicate only with their immediate neighbours/friends in a social network/graph. To cope with these problems, we propose a novel Federated learning algorithm for DOSNs based on the Gossip protocol. We propose a two layer protocol in which the underlying layer is a socially-aware gossip sampling protocol and the upper layer is a push-based merging gossip protocol. The former is responsible for creating a socially-aware random overlay network while the latter, utilizing the sampling protocol, does the training model. We implement our algorithm and through extensive experiments show that the algorithm trains the model up to 88% accuracy compared to the centralized approach.
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| 40972. |
- Khemiri, Lotfi, et al.
(författare)
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Suicide Risk Associated with Experience of Violence and Impulsivity in Alcohol Dependent Patients
- 2016
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Ingår i: Scientific Reports. - : Springer Nature. - 2045-2322. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- Alcohol dependence (AD) and aggression-impulsivity are both associated with increased suicide risk. There is a need to evaluate clinical tools in order to improve suicide risk assessment of AD patients. The present study consisted of 95 individuals with a diagnosis of AD, consecutively admitted for addiction treatment, compared with 95 healthy controls. Suicidal risk was assessed together with exposure of violence and impulsivity. AD patients reported significantly higher rates of exposure to violence in childhood, as measured by the Karolinska Interpersonal Violence Scale (KIVS), compared to HC. Within the AD group, individuals with history of suicidal ideation and suicidal behavior reported higher levels of violence experience compared to AD individuals without such history. AD patients with previous suicidal ideation scored higher on self-reported impulsivity as assessed by the Barratt Impulsivity Scale (BIS). Our main finding was that experience of trauma and expression of violent behavior, coupled with increased impulsivity are associated with an elevated suicide risk in AD patients. Future longitudinal studies assessing these traits are needed to evaluate their potential role in identifying AD patients at risk of future suicide.
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| 40973. |
- Khemtémourian, Lucie, et al.
(författare)
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Synthesis and secondary structure in membranes of the Bcl-2 anti-apoptotic domain BH4
- 2006
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Ingår i: Journal of Peptide Science. - : Wiley. - 1075-2617 .- 1099-1387. ; 12, s. 58-64
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Tidskriftsartikel (refereegranskat)abstract
- Solid phase synthesis of BH4, the 26 amino-acid domain (6RTGYDNREIVMKYIHYKLSQRGYEWD31) of the anti-apoptotic Bcl-2 protein has been accomplished using Fmoc chemistry. The use of peculiar cleavage conditions provided high yields after purification such that tens to hundreds of mg could be obtained. A 15N-labelled version of the peptide could also be synthesized for NMR studies in membranes. The peptide purity was not lower than 98% as controlled by UV and MALDI-TOF mass spectrometry. The secondary structure was determined in water, trifluoroethanol (TFE) and in lipid membrane using UV circular dichroism. The peptide shows dominant -sheeted structures in water that convert progressively into -helical features upon addition of TFE or membrane. The amphipathic character of the helix suggests that the peptide might have a structure akin to those of antimicrobial peptides upon interaction with membranes. Copyright © 2005 European Peptide Society and John Wiley & Sons, Ltd.
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| 40974. |
- Khetani, Mary A., et al.
(författare)
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Early intervention service intensity and young children's home participation
- 2020
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Ingår i: BMC Pediatrics. - : BioMed Central (BMC). - 1471-2431. ; 20:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Young children with developmental disabilities and delays spend significant amounts of time at home, show decreased participation in home-based activities, and receive home-based early intervention services to improve participation in activities. Yet, knowledge about the relationship between EI service use and children’s home participation in activities remains poorly understood but needed for program improvement. The purpose of this study was to understand the relationships between EI service use and children’s home participation.Methods: In a cross-sectional design, data were gathered from caregivers (N = 139) who enrolled in a pilot trial of the Young Children’s Participation in Environment Measure (YC-PEM) electronic patient-reported outcome (e-PRO), as implemented within 1 month of their child’s next EI progress evaluation. A series of path analytic models were used to estimate EI service intensity as a predictor of parent-reported young children’s home participation 1) frequency, 2) level of involvement, and 3) desired change, adjusting for family and child social and functional characteristics. Models included caregiver perceptions of home environmental support to test its indirect (i.e., mediation) effects on the relationship between EI service intensity and each of the three home participation dimensions.Results: All three models fit the data well (comparative fit index = 1.00). EI service intensity was not a significant predictor of participation frequency. However, EI service intensity had a significant direct effect on a child’s participation according to level of involvement and desired change, explaining between 13.3–33.5% of the variance in home participation. Caregiver perceptions of environmental support had a small yet significant indirect effect on the relationship between EI service intensity and level of involvement and desired change; these models explained between 18.5–38.1% of the variance in home participation.Conclusions: EI service intensity has important links with involvement in and desired change for home-based activities. Caregiver perceptions of environmental support appears to be a factor in the relationship between EI service intensity and home participation. Results warrant longitudinal replication with a control group, which would be possible with the implementation of the YC-PEM e-PRO in a routine EI clinical workflow.
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| 40975. |
- Khmelinskii, Anton, et al.
(författare)
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Seamless gene tagging by endonuclease-driven homologous recombination.
- 2011
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 6:8
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Tidskriftsartikel (refereegranskat)abstract
- Gene tagging facilitates systematic genomic and proteomic analyses but chromosomal tagging typically disrupts gene regulatory sequences. Here we describe a seamless gene tagging approach that preserves endogenous gene regulation and is potentially applicable in any species with efficient DNA double-strand break repair by homologous recombination. We implement seamless tagging in Saccharomyces cerevisiae and demonstrate its application for protein tagging while preserving simultaneously upstream and downstream gene regulatory elements. Seamless tagging is compatible with high-throughput strain construction using synthetic genetic arrays (SGA), enables functional analysis of transcription antisense to open reading frames and should facilitate systematic and minimally-invasive analysis of gene functions.
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| 40976. |
- Khodabakhsh, Amir, et al.
(författare)
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Cavity-Enhanced Continuous-Filtering Vernier Spectroscopy at 3.3 mu m using a Femtosecond Optical Parametric Oscillator
- 2017
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Ingår i: 2017 CONFERENCE ON LASERS AND ELECTRO-OPTICS EUROPE & EUROPEAN QUANTUM ELECTRONICS CONFERENCE (CLEO/EUROPE-EQEC). - : IEEE. - 9781509067367 ; , s. CH_2_2-
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Konferensbidrag (refereegranskat)abstract
- Optical frequency comb spectroscopy in the mid-infrared fingerprint region combines broad spectral bandwidth with high detection sensitivity and allows simultaneous detection of trace amounts of many molecular species. We have recently demonstrated a continuous-filtering Vernier spectrometer based on a mid-infrared optical frequency comb and an enhancement cavity for fast and sensitive detection of CH4 [1]. Here we present an improved, fully automatized and frequency calibrated continuous-filtering Vernier spectrometer, schematically shown in Fig. 1(a). The comb source is a doubly resonant optical parametric oscillator (DROPO) based on an orientation-patterned GaAs crystal synchronously pumped by a Tm:fiber femtosecond laser (125 MHz repetition rate, frep). The signal comb (3.1–3.4 µm, 30 mW) is mode matched to a 60-cm long Vernier enhancement cavity with a finesse of ~350 at 3.25 μm, placed in an enclosure that can be filled with the gas sample. The output mirror is attached to a PZT and mounted on a translation stage. When the cavity free spectral range is perfectly matched to twice the frep (250 MHz) every other signal comb mode is transmitted through the cavity. By detuning the cavity length from this perfect match position the cavity resonances act as a filter and transmit groups of comb modes called Vernier orders [2]. A diffraction grating mounted on a galvo-scanner separates these orders after the cavity and the chosen order is sent to the detection system. The Vernier order is tuned across the signal comb spectrum by scanning the cavity length (at 20 Hz) and the grating is rotated synchronously to fix the order in space and allow acquisition of the entire spectrum in 25 ms. Any residual mismatch between the cavity length scan and the grating rotation is compensated by a feedback loop acting on the frep of the pump laser and the PZT of the Vernier cavity [2]. A Fabry-Perot etalon is used for frequency calibration of the spectrometer. Figure 1(b) shows in black the normalized transmission spectrum of a sample containing 5.0 ppm CH4 and 160 ppm water. The red and blue curves show the corresponding fit of the Vernier spectrum [3] of CH4 and water, respectively, calculated using Voigt profiles, line parameters from the HITRAN database, and the experimentally determined cavity finesse. The figure of merit of the spectrometer is 1×10−9cm−1 Hz−1∕2 per spectral element and multiline fitting yields minimum detectable concentration of CH4 of 2 ppb in 25 ms, translating into 400 ppt Hz−1∕2 Since the spectrum of the signal comb covers the fundamental C-H stretch transitions we expect low detection limits for other hydrocarbons as well. In conclusion, mid-infrared comb-based continuous-filtering Vernier spectroscopy allows fast and highly sensitive measurement of broadband absorption spectra using a robust and compact detection system.
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| 40977. |
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| 40978. |
- Khodabakhsh, Amir, et al.
(författare)
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Cavity-Enhanced Optical Frequency Comb Spectroscopy of High-Temperature Water in a Flame
- 2015
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Ingår i: 2015 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO). - 9781557529688
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Konferensbidrag (refereegranskat)abstract
- We demonstrate detection of broadband high-temperature water spectra in a laminar, premixed methane/air flat flame using high-resolution near-infrared cavity-enhanced optical frequency comb spectroscopy incorporating a fast-scanning Fourier transform spectrometer.
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| 40979. |
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| 40980. |
- Khodabakhsh, Amir, et al.
(författare)
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Fourier transform and Vernier spectroscopy using an optical frequency comb at 3-5.4 μm
- 2016
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Ingår i: Optics Letters. - 0146-9592 .- 1539-4794. ; 41:11, s. 2541-2544
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Tidskriftsartikel (refereegranskat)abstract
- We present a versatilemid-infrared frequency comb spectroscopy system based on a doubly resonant optical parametric oscillator tunable in the 3-5.4 mu m range and two detection methods: a Fourier transform spectrometer (FTS) and a continuous-filtering Vernier spectrometer (CF-VS). Using the FTS with a multipass cell, we measure high precision broadband absorption spectra of CH4 at 3.3 mu m and NO at 5.25 mu m, the latter for the first time with comb spectroscopy, and we detect atmospheric species (CH4, CO, CO2, and H2O) in air in the signal and idler ranges. Multiline fitting yields minimum detectable concentrations of 10-20 ppbHz-1/2 for CH4, NO, and CO. For the first time in the mid-infrared, we perform CF-VS using an enhancement cavity, a grating, and a single detector, and we measure the absorption spectrum of CH4 and H2O in ambient air at similar to 3.3 m mu, reaching a 40 ppb concentration detection limit for CH4 in 2 ms.
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