27 research outputs found
Evaluating Threshold for Retraining Rule in Semi-Supervised Learning using Multi-Expert System
No full textThe creation of training set, for pattern recognition, is a difficult, expensive and time consuming task because it requires the efforts of experienced human annotators. On the other hand, unlabeled data can be obtained cheaply, but there are few ways to use them. Semi-Supervised learning uses both labeled and unlabeled data for classification task. In this paper we propose to apply semi-supervised learning and three methods in order to re-train individual classifiers in a multi-expert scenario. More specifically, these experiments are focused on acceptance threshold that defines what data are selected in the feedback-based process. Our approach analyzes the entire system so that a misclassified sample, respect to the final decision, by particular expert can be used to update itself if that sample is classified with a confidence greater than a specific threshold. Experimental results, carried out on the CEDAR (handwritten digits) database, show a comparison between our approach and Self-Training and Co-Training algorithms. The SVM classifier and two different combination techniques at measurement level have been used
Similarity-based regularization for semi-supervised learning for handwritten digit recognition
No full textThis paper presents an experimental analysis on the use of semi-supervised learning in the handwritten digit recognition field. More specifically, two new feedback-based techniques for retraining individual classifiers in a multi-expert scenario are discussed. These new methods analyze the final decision provided by the multi-expert system so that sample classified with a confidence greater than a specific threshold is used to update the system itself. Experimental results carried out on the CEDAR (handwritten digits) database are presented. In particular, error rate, similarity index and a new correlation score among them are considered in order to evaluate the best retraining rule. For the experimental evaluation, an SVM classifier and five different combination techniques at abstract and measurement level have been used. Finally, the results show that iterating the feedback process, on different multi-expert systems built with the five combination techniques, one retraining rule is winning over the other respect to the best correlation score
Real-Time Applications In 803.11 WLAN Using Feedback-Based Bandwidth Allocation
No full textThe Hybrid Coordination Function (HCF) has been recently proposed by the 802.11e working group in order to provide real-time services in Wireless Local Area Networks (WLANs). HCF is made of a contention-based channel access, known as Enhanced Distributed Coordination Access (EDCA), and of a HCF Controlled Channel Access (HCCA), which requires a centralized controller, called Hybrid Coordinator (HC). This paper proposes two feedback-based bandwidth allocation algorithms exploiting HCCA for dynamically assigning the WLAN channel bandwidth to mobile stations hosting real-time traffic streams. Proposed algorithms, which have been referred to as Feedback Based Dynamic Scheduler (FBDS) and Proportional Integral (PI)-FBDS, have been designed using classic discrete-time feedback control theory. Simulation results, obtained using the ns-2 simulator, have shown that, unlike the simple scheduler proposed by the 802.11e working group, both FBDS and PI-FBDS provide a real-time service regardless of the network load. Moreover, when the PI-FBDS is used, the best trade-off between one-way packet delays and network utilization is achieved
Voronoi Tessellation for Effective and Efficient Handwritten Digit Classification
No full textThe aim of this paper is to explore the
properties of a new zoning technique based on Voronoi
tessellation for the task of handwritten digit recognition.
This technique extracts features according to an optimal
zoning distribution, obtained by an evolutionary-strategy
based search. Extensive experiments have been conducted
on the MNIST dataset to investigate strengths and
weakness of the proposed approach. Comparisons with
regular square zoning reveal that the presented zoning
strategy achieves better results with any type of features.
Furthermore, the proposed zoning method, jointly with a
suitable choice of features, allows a low complexity
classifier to reach excellent performances both in terms of
accuracy and speed
Writing Generation Model for Health Care neuromuscular System
No full textIn this paper the use of handwriting artifacts for health investigation is addressed. For the purpose, the paper first presents the Delta-Log and Sigma-Lognormal models to investigate on the handwriting generation processes carried out by the neuromuscular system. Successively, a computational system for handwriting analysis is presented and some considerations are exploited about the use of the model to investigate insurgence and monitoring of some neuromuscular diseases. The experimental results show the validity of the proposed approach and highlight some directions for further research
Equilibria between α and β Isomers of Keggin Heteropolytungstates
No full textConventional wisdom maintains that β isomers of fully oxidized Keggin heteropolytungstates,
[Xn+WVI12O40](8-n)- (X = main-group or transition-metal cation), are unstable with respect to α structures
such that isomeric rearrangements all occur in the direction β → α. Contrary to this view, equilibria between
α and β forms of the Keggin anion [AlIIIW12O40]5- (α- and β-1) have now been observed. Moreover, a trend
in kinetic and thermodynamic stabilities of β isomers in the order X = Al(III) > Si(IV) > P(V) has been
established, and the difference in energy between α and β isomers (α- and β-1) has been quantified for the
first time. Mild acid condensation of WO42-, followed by addition of Al(III), gave [Al(AlOH2)W11O39]6-
(2)three β-isomer derivatives, β1 (Cs symmetry), β2 (C1), and β3 (Cs), with the α derivative (Cs) a minor
productin nearly quantitative yield by 27Al NMR spectroscopy. Acidification of the reaction mixture to pH
0 and refluxing cleanly converted 2 to H5[AlIIIW12O40] (1)mostly β-1 (yellow, C3v), with α-1 (white, Td) a
minor product. Samples of each isomer were isolated by fractional crystallization and characterized by 27Al
and 183W NMR, IR, and UV−vis spectroscopy, cyclic voltammetry, and single-crystal X-ray diffraction. The
Al−O bond length in the Td AlO4 group at the center of α-1 (hydrated potassium salt of α-1; final R1 =
3.42%) establishes a trend in X−O bond lengths in the [Xn+O4](8-n)- groups of α-Keggin anions of 1.74(1),
1.64(2), and 1.53(1) Å, respectively, for X = Al(III), Si(IV), and P(V). Equilibria between isomers of 1 were
observed by heating separate 0.1 M aqueous solutions of either pure α or β anions under identical conditions.
The progress of the reaction was measured, and the relative concentrations of the α and β isomers present at
equilibrium were determined by 27Al NMR spectroscopy. First-order rate constants for approach to equilibrium
of α- and β-1 at 473 K were k1(α→β) = 7.68 × 10-7 s-1 and k-1(β→α) = 6.97 × 10-6 s-1. The equilibrium ratio
of β-1 to α-1 (k1/k-1) was Keq(473 K, 0.1 M 1) = 0.11 ± 0.01. From ΔG = −RT ln Keq, α-1 is more stable than
β-1 by 2.1 ± 0.5 kcal mol-1. Controlled hydrolysis of α-1 gave the monolacunary derivative α-Na9[AlW11O39]
(α-3; Cs); hydrolysis of β-1 gave β2-3 (C1) as the major product. Thermal equilibration of the lacunary Keggin
heteropolytungstates could also be achieved: Independently heated solutions of either α-3 or β2-3 (0.13 M of
either isomer in D2O at 333 K; natural pH values of ca. 7) both gave solutions containing α-3 (60%) and a
single β-3 isomer of Cs symmetry (40%). Using Keq = 1.5, the two isomers differ in energy by 0.3 kcal mol-1
Equilibria between α and β Isomers of Keggin Heteropolytungstates
No full textConventional wisdom maintains that β isomers of fully oxidized Keggin heteropolytungstates,
[Xn+WVI12O40](8-n)- (X = main-group or transition-metal cation), are unstable with respect to α structures
such that isomeric rearrangements all occur in the direction β → α. Contrary to this view, equilibria between
α and β forms of the Keggin anion [AlIIIW12O40]5- (α- and β-1) have now been observed. Moreover, a trend
in kinetic and thermodynamic stabilities of β isomers in the order X = Al(III) > Si(IV) > P(V) has been
established, and the difference in energy between α and β isomers (α- and β-1) has been quantified for the
first time. Mild acid condensation of WO42-, followed by addition of Al(III), gave [Al(AlOH2)W11O39]6-
(2)three β-isomer derivatives, β1 (Cs symmetry), β2 (C1), and β3 (Cs), with the α derivative (Cs) a minor
productin nearly quantitative yield by 27Al NMR spectroscopy. Acidification of the reaction mixture to pH
0 and refluxing cleanly converted 2 to H5[AlIIIW12O40] (1)mostly β-1 (yellow, C3v), with α-1 (white, Td) a
minor product. Samples of each isomer were isolated by fractional crystallization and characterized by 27Al
and 183W NMR, IR, and UV−vis spectroscopy, cyclic voltammetry, and single-crystal X-ray diffraction. The
Al−O bond length in the Td AlO4 group at the center of α-1 (hydrated potassium salt of α-1; final R1 =
3.42%) establishes a trend in X−O bond lengths in the [Xn+O4](8-n)- groups of α-Keggin anions of 1.74(1),
1.64(2), and 1.53(1) Å, respectively, for X = Al(III), Si(IV), and P(V). Equilibria between isomers of 1 were
observed by heating separate 0.1 M aqueous solutions of either pure α or β anions under identical conditions.
The progress of the reaction was measured, and the relative concentrations of the α and β isomers present at
equilibrium were determined by 27Al NMR spectroscopy. First-order rate constants for approach to equilibrium
of α- and β-1 at 473 K were k1(α→β) = 7.68 × 10-7 s-1 and k-1(β→α) = 6.97 × 10-6 s-1. The equilibrium ratio
of β-1 to α-1 (k1/k-1) was Keq(473 K, 0.1 M 1) = 0.11 ± 0.01. From ΔG = −RT ln Keq, α-1 is more stable than
β-1 by 2.1 ± 0.5 kcal mol-1. Controlled hydrolysis of α-1 gave the monolacunary derivative α-Na9[AlW11O39]
(α-3; Cs); hydrolysis of β-1 gave β2-3 (C1) as the major product. Thermal equilibration of the lacunary Keggin
heteropolytungstates could also be achieved: Independently heated solutions of either α-3 or β2-3 (0.13 M of
either isomer in D2O at 333 K; natural pH values of ca. 7) both gave solutions containing α-3 (60%) and a
single β-3 isomer of Cs symmetry (40%). Using Keq = 1.5, the two isomers differ in energy by 0.3 kcal mol-1
Simulation Based Assessment Of Energy Consumption Optimization In 3g Mobiles
No full textThe energy consumption in mobile devices had gained more attention from infra-structure carriers and mobile manufacturers with the growth and expansion of third generation networks. The air interface resource allocation is the main factor of the energy consumption increase when the mobile is transmitting in background at anytime. When the air interface timeouts are reduced, there is a reduction in energy consumption. The aim of this work is, by simulating the mobile behavior, to identify the best timeout values to bet set according to specific carrier or user traffic profile and to obtain the best gain in energy consumption reduction. ©2011 IEEE.IEEE Wuhan Section,Hunan University,Wuhan University,Engineering Information Institute,Chongqing VIP Information Co., LtdLee Patrick, P.C., Bu, T., Woo, T., On the detection of signaling DoS attacks on 3G wireless networks (2007) 26th IEEE International Conference on Computer CommunicationsFabio, R., Unwanted traffic in 3G networks (2006) ACM SIGCOMM Computer Communication Review, 36 (2). , AprilPerälä, P.H.J., Barbuzzi, A., Kostas, P., Theory and practice of RRC state transitions in UMTS networks (2009) 5TH IEEE Broadband Wireless Access Workshop, , JulyHenry, H., Jonne, S., Pasi, E., Energy consumption of always-on applications in WCDMA networks (2007) Proceedings of the 65th Semi-annual IEEE Vehicular Technology Conference, , (Dublin, Ireland). AprilLee, C.-C., Yeh, J.-H., Chen, J.-C., Comparative analysis of energy-saving techniques in 3GPP and 3GPP2 systems (2009) IEEE Trans Veh Tech, 58, pp. 432-448Lee, C.-C., Yeh, J.-H., Chen, J.-C., Impact of inactivity timer on energy consumption in WCDMA and cdma2000 (2004) Proc. Wireless Telecommunications Symposium, , IEEEPeng, M., Wang, W., An adaptive energy saving mechanism in the wireless packet access network (2008) Proceedings of the IEEE WCNC 2008 - Wireless Communications and Networking Conference, pp. 1536-1540. , Las Vegas, USA, AprChen, J.-C., Tao, Z., (2004) IP-based Next-generation Wireless Networks. System, Architectures and Protocols, , Wiley-InterscienceDo Prado, D.S., (1999) Usando o ARENA Em Simulação, , Série Pesquisa Operacional - Belo Horizonte: Editora de Desenvolvimento GerencialKelton, W.D., Sadowski, R.P., Sadowski, D.A., (2001) Simulation with ARENA, , McGraw-Hill Higher EducationJain, R., (1991) The Art of Computer Systems Performance Analysis, , WileyAndres, A., Yla-Jääski, A., VoIP call signaling performance and always-on battery consumption in HSDPA, WCDMA and WiFi (2007) Proceedings of the 3rd International Conference on Wireless Communications, Networking and Mobile Computing (WiCOM 2007), pp. 2964-2967. , Shanghai, China. 21-23 SeptemberUniversal Mobile Telecommunications System (UMTS) Radio Resource Control (RRC) Protocol Specification, , ETSI 3GPP TS 25.331. Version 9.1.0, Release
Equilibrating metal-oxide cluster ensembles for oxidation reactions using oxygen in water
No full text
