Showing papers by "Northeastern University (China) published in 2013"
TL;DR: Experimental results demonstrate that the proposed approach presents the performance of defect recognition under the influence of the feature variations of the intra-class changes, the illumination and grayscale changes, and even in the toughest situation with additive Gaussian noise, the AECLBP can still achieve the moderate recognition accuracy.
433 citations
TL;DR: The novel weight tuning laws for critic neural networks are proposed, which not only ensure the Nash equilibrium to be reached but also guarantee the system to be stable and demonstrate the uniform ultimate boundedness of the closed-loop system.
Abstract: In this paper, a near-optimal control scheme is proposed to solve the nonzero-sum differential games of continuous-time nonlinear systems. The single-network adaptive dynamic programming (ADP) is utilized to obtain the optimal control policies which make the cost functions reach the Nash equilibrium of nonzero-sum differential games, where only one critic network is used for each player instead of the action-critic dual network used in a typical ADP architecture. Furthermore, the novel weight tuning laws for critic neural networks are proposed, which not only ensure the Nash equilibrium to be reached but also guarantee the system to be stable. No initial stabilizing control policy is required for each player. Moreover, Lyapunov theory is utilized to demonstrate the uniform ultimate boundedness of the closed-loop system. Finally, a simulation example is given to verify the effectiveness of the proposed near-optimal control scheme.
375 citations
TL;DR: In this paper, a brief review is given regarding ultrafast laser micromachining of materials and some general experimental observations are first provided to show the characteristics of ultrafast LMMM.
Abstract: A brief review is given regarding ultrafast laser micromachining of materials. Some general experimental observations are first provided to show the characteristics of ultrafast laser micromachining. Apart from empirical research, mathematical models also appear to allow for a further and systematic understanding of these phenomena. A few fundamental ultrafast laser micromachining mechanisms are addressed in an attempt to highlight the physics behind the experimental observations and the mathematical models. It is supposed that a vivid view of ultrafast laser micromachining has been presented by linking experimental observations, mathematical models and the behind physics.
322 citations
TL;DR: The parameter domain is derived which is defined as the set of competing intensities for which the CLSC with dual recycling channel outperforms theCLSC with single recycling channel from the perspectives of the manufacturer and the consumers, respectively.
296 citations
TL;DR: A continuous feedback controller is designed for the switched system, which guarantees that asymptotic output tracking is achieved without transgression of the constraints and all closed-loop signals remain bounded, provided that the initial states are feasible.
291 citations
01 Dec 2013
TL;DR: This paper investigates the publication of DP-compliant histograms, which is an important analytical tool for showing the distribution of a random variable, e.g., hospital bill size for certain patients, and proposes two novel mechanisms, namely NoiseFirst and StructureFirst, for computing DP- Compliant histogram structure.
Abstract: Differential privacy (DP) is a promising scheme for releasing the results of statistical queries on sensitive data, with strong privacy guarantees against adversaries with arbitrary background knowledge. Existing studies on differential privacy mostly focus on simple aggregations such as counts. This paper investigates the publication of DP-compliant histograms, which is an important analytical tool for showing the distribution of a random variable, e.g., hospital bill size for certain patients. Compared to simple aggregations whose results are purely numerical, a histogram query is inherently more complex, since it must also determine its structure, i.e., the ranges of the bins. As we demonstrate in the paper, a DP-compliant histogram with finer bins may actually lead to significantly lower accuracy than a coarser one, since the former requires stronger perturbations in order to satisfy DP. Moreover, the histogram structure itself may reveal sensitive information, which further complicates the problem. Motivated by this, we propose two novel mechanisms, namely NoiseFirst and StructureFirst, for computing DP-compliant histograms. Their main difference lies in the relative order of the noise injection and the histogram structure computation steps. NoiseFirst has the additional benefit that it can improve the accuracy of an already published DP-compliant histogram computed using a naive method. For each of proposed mechanisms, we design algorithms for computing the optimal histogram structure with two different objectives: minimizing the mean square error and the mean absolute error, respectively. Going one step further, we extend both mechanisms to answer arbitrary range queries. Extensive experiments, using several real datasets, confirm that our two proposals output highly accurate query answers and consistently outperform existing competitors.
249 citations
TL;DR: A high energy density asymmetric supercapacitor with nickel oxide nanoflake arrays as the cathode and reduced graphene oxide as the anode and an excellent charge/discharge cycling performance in 1.0 M KOH electrolyte with a capacitance retention of 95% after 3000 cycles.
Abstract: Here we demonstrate a high energy density asymmetric supercapacitor with nickel oxide nanoflake arrays as the cathode and reduced graphene oxide as the anode. Nickel oxide nanoflake arrays were synthesized on a flexible carbon cloth substrate using a seed-mediated hydrothermal method. The reduced graphene oxide sheets were deposited on three-dimensional (3D) nickel foam by hydrothermal treatment of nickel foam in graphene oxide solution. The nanostructured electrodes provide a large effective surface area. The asymmetric supercapacitor device operates with a voltage of 1.7 V and achieved a remarkable areal capacitance of 248 mF cm−2 (specific capacitance of 50 F g−1) at a charge/discharge current density of 1 mA cm−2 and a maximum energy density of 39.9 W h kg−1 (based on the total mass of active materials of 5.0 mg). Furthermore, the device showed an excellent charge/discharge cycling performance in 1.0 M KOH electrolyte at a current density of 5 mA cm−2, with a capacitance retention of 95% after 3000 cycles.
245 citations
TL;DR: By defining a more general type of Lyapunov functionals, some new less conservative delay-dependent stability criteria are obtained and shown in terms of linear matrix inequalities (LMIs).
Abstract: In this paper, a novel method is developed for the stability problem of a class of neural networks with time-varying delay. New delay-dependent stability criteria in terms of linear matrix inequalities for recurrent neural networks with time-varying delay are derived by the newly proposed augmented simple Lyapunov-Krasovski functional. Different from previous results by using the first-order convex combination property, our derivation applies the idea of second-order convex combination and the property of quadratic convex function which is given in the form of a lemma without resorting to Jensen's inequality. A numerical example is provided to verify the effectiveness and superiority of the presented results.
219 citations
TL;DR: These CNPs have a distinct pH-sensitive feature that gives them the potential to serve as a proton sensor in monitoring cell metabolization process with proton release and exhibit low cytotoxicity and favorable biocompatibility.
197 citations
TL;DR: An extended TODIM method is proposed to solve the hybrid MADM problem and two numerical examples are used to illustrate the use of the proposed method.
Abstract: TODIM (an acronym in Portuguese of interactive and multiple attribute decision making) is a method for solving the multiple attribute decision making (MADM) problem considering decision maker's (DM's) behavior, in which the attribute values are in the format of crisp numbers. It cannot be used to handle hybrid MADM problems with various formats of attribute values. In this paper, an extended TODIM method is proposed to solve the hybrid MADM problem. First, three formats of attribute values (crisp numbers, interval numbers and fuzzy numbers) are expressed in the format of random variables with cumulative distribution functions. Then, according to the concept of the classical TODIM method, the gain and loss matrices concerning each attribute are constructed by calculating the gain and loss of each alternative relative to the others. Further, by calculating the dominance degree of each alternative over the others, the overall value of each alternative can be obtained to rank the alternatives. Finally, two numerical examples are used to illustrate the use of the proposed method.
185 citations
Proceedings Article•
01 Aug 2013
TL;DR: This work proposes a simple yet effective extension to the shift-reduce process, which eliminates size differences between action sequences in beam-search and gives comparable accuracies to the state-of-the-art chart parsers.
Abstract: Shift-reduce dependency parsers give comparable accuracies to their chartbased counterparts, yet the best shiftreduce constituent parsers still lag behind the state-of-the-art. One important reason is the existence of unary nodes in phrase structure trees, which leads to different numbers of shift-reduce actions between different outputs for the same input. This turns out to have a large empirical impact on the framework of global training and beam search. We propose a simple yet effective extension to the shift-reduce process, which eliminates size differences between action sequences in beam-search. Our parser gives comparable accuracies to the state-of-the-art chart parsers. With linear run-time complexity, our parser is over an order of magnitude faster than the fastest chart parser.
TL;DR: This paper proposes relaxed stabilization conditions of discrete-time nonlinear systems in the Takagi-Sugeno (T-S) fuzzy form by using the algebraic property of fuzzy membership functions to develop a novel nonparallel distributed compensation (non-PDC) control scheme based on a new class of fuzzy Lyapunov functions.
Abstract: This paper proposes relaxed stabilization conditions of discrete-time nonlinear systems in the Takagi-Sugeno (T-S) fuzzy form. By using the algebraic property of fuzzy membership functions, a novel nonparallel distributed compensation (non-PDC) control scheme is proposed based on a new class of fuzzy Lyapunov functions. Thus, relaxed stabilization conditions for the underlying closed-loop fuzzy system are developed by applying a new slack variable technique. In particular, some existing fuzzy Lyapunov functions and non-PDC control schemes are special cases of the new Lyapunov function and fuzzy control scheme, respectively. Finally, two numerical examples are provided to illustrate the effectiveness of the proposed method.
TL;DR: The piezoelectric signal generated by a ZnO NWs NG can act not only as a power source, but also as a response signal to the gas, demonstrating a possible approach as a self-powered active gas sensor.
Abstract: The output of a piezoelectric nanogenerator (NG) fabricated using ZnO nanowire arrays is largely influenced by the density of the surface charge carriers at the nanowire surfaces. Adsorption of gas molecules could modify the surface carrier density through a screening effect, thus, the output of the NG is sensitive to the gas concentration. Based on such a mechanism, we first studied the responses of an unpackaged NG to oxygen, H2S and water vapor, and demonstrated its sensitivity to H2S to a level as low as 100 ppm. Therefore, the piezoelectric signal generated by a ZnO NWs NG can act not only as a power source, but also as a response signal to the gas, demonstrating a possible approach as a self-powered active gas sensor.
15 Nov 2013-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this paper, the effect of temperature, strain rate, and strain on the microstructure of dynamically recrystallized nickel-chromium alloy (800H) subjected to hot compression over a wide range of strain rates was analyzed.
Abstract: The objective of the study described here is to evaluate the effect of temperature, strain rate, and strain on the microstructure of dynamically recrystallized nickel–chromium alloy (800H) subjected to hot compression over a wide range of strain rates. The microstructural evolution was studied by electron backscattered diffraction (EBSD) and the effect of adiabatic heating on hot deformation was analyzed to correct the flow curves at high strains. The grain orientation spread (GOS) approach was used to distinguish the dynamic recrystallization (DRX) grains from the deformed matrix. The nucleation mechanism of DRX and the role of Σ 3 n CSL boundaries during DRX were explored. Additionally, the influence of carbides on the DRX behavior was studied within the temperature of 850–950 °C. The results indicated that the DRX can be stimulated by adiabatic heating and strong dislocation–dislocation interaction occurring with increase in the strain rate in the range of 1–30 s −1 . The threshold value of GOS (1.2°) separated the DRX grains from the deformed matrix. The recrystallized grains nucleated at pre-existing grain boundaries by extensive bulging associated with grain fragmentation. The Σ 3 n CSL boundaries play an important role in DRX and they can be generated through interaction among them after the initiation of DRX. The precipitation of Cr 23 C 6 and Ti(C, N) at the parent grain boundary could restrain or even inhibit the occurrence of DRX in the temperature range of 850–950 °C.
TL;DR: Reflection-mode plasmonic color filters based on lithographically patterned silver nanorods with ultrasmall inter-rod gaps using dense nanorod arrays are demonstrated, potentially useful for plAsmon-assisted sensing, imaging and displays.
Abstract: We demonstrate reflection-mode plasmonic color filters based on lithographically patterned silver nanorods with ultrasmall inter-rod gaps. Fine and effective tuning of the plasmon resonance is shown by varying array periodicities. We determine the dependence of reflected intensity on diameter/periodicity ratio and then develop reflective plasmonic color filters using dense nanorod arrays. Experimental results agree well with theoretical calculations. Our approach is potentially useful for plasmon-assisted sensing, imaging and displays.
TL;DR: An effective artificial bee colony (ABC) algorithm with the job-permutation-based representation for solving the scheduling problem resulting from a steelmaking process is proposed.
Abstract: This paper aims to provide a solution method for the real-world hybrid flowshop scheduling problem resulting from a steelmaking process, which has important applications in modern iron and steel industry. We first present a mixed integer mathematic model based on a comprehensive investigation. Then, we develop a heuristic method and two improvement procedures for a given schedule based on the problem-specific characteristics. Finally, we propose an effective artificial bee colony (ABC) algorithm with the job-permutation-based representation for solving the scheduling problem. The proposed ABC algorithm incorporates the heuristic and improvement procedures as well as new characteristics including a neighboring solution generation method and two enhanced strategies. To evaluate the proposed algorithm, we present several adaptations of other well-known and recent metaheuristics to the problem and conduct a serial of experiments with the instances generated according to real-world production process. The results show that the proposed ABC algorithm is more effective than all other adaptations after comprehensive computational comparisons and statistical analysis.
TL;DR: A simple multifunctional nanoparticle system that can deliver DOX to the targeted cancer cells and enable us to localize the graphene-HQDs and monitor intracellular DOX release has been demonstrated in vitro.
TL;DR: Carbon dots (C-dots) have been proven to show the capability for direct reduction of Ag(+) to elemental silver (Ag(0)) without additional reducing agent or external photoirradiation by incubating Ag(+ with C-d dots for 5 min in a water bath at 50 °C.
Abstract: Carbon dots (C-dots) have been proven to show the capability for direct reduction of Ag+ to elemental silver (Ag0) without additional reducing agent or external photoirradiation by incubating Ag+ with C-dots for 5 min in a water bath at 50 °C. Silver nanoparticles (Ag-NPs) are simultaneously formed with an average size of 3.1 ± 1.5 nm and grew on carbon dots. This process involves the oxidation of amine or phenol hydroxyl groups on the aromatic ring of C-dots. Meanwhile C-dots protect and stabilize the Ag-NPs from aggregation in aqueous medium; that is, the Ag-NPs are stable at least for 45 days in aqueous medium. The formed Ag-NPs cause significant resonance light scattering (RLS), which correlates closely with the concentration of silver cation, and this facilitates quantitative detection of silver in aqueous medium.
TL;DR: Novel LMI conditions with a line search over a scalar variable for designing robust SOF controllers are proposed, where the uncertain output matrix of the considered system is allowed to be not of full row rank.
TL;DR: Computational study on the biobjective and three-objective benchmark problems shows that the HMOEA is competitive or superior to previous multiobjective algorithms in the literature.
Abstract: Recently, the hybridization between evolutionary algorithms and other metaheuristics has shown very good performances in many kinds of multiobjective optimization problems (MOPs), and thus has attracted considerable attentions from both academic and industrial communities. In this paper, we propose a novel hybrid multiobjective evolutionary algorithm (HMOEA) for real-valued MOPs by incorporating the concepts of personal best and global best in particle swarm optimization and multiple crossover operators to update the population. One major feature of the HMOEA is that each solution in the population maintains a nondominated archive of personal best and the update of each solution is in fact the exploration of the region between a selected personal best and a selected global best from the external archive. Before the exploration, a selfadaptive selection mechanism is developed to determine an appropriate crossover operator from several candidates so as to improve the robustness of the HMOEA for different instances of MOPs. Besides the selection of global best from the external archive, the quality of the external archive is also considered in the HMOEA through a propagating mechanism. Computational study on the biobjective and three-objective benchmark problems shows that the HMOEA is competitive or superior to previous multiobjective algorithms in the literature.
TL;DR: The proposed scheme introduces a substitution mechanism in the permutation process through a bit-level shuffling algorithm to address the efficiency problem encountered by many existing permutation-substitution type image ciphers.
TL;DR: This article focuses on the tracking control problem for switched nonlinear systems in strict-feedback form subject to an output constraint, and a barrier Lyapunov function is employed, which grows to infinity when its arguments approach domain boundaries.
Abstract: This article focuses on the tracking control problem for switched nonlinear systems in strict-feedback form subject to an output constraint. In order to prevent transgression of the constraint, a barrier Lyapunov function is employed, which grows to infinity when its arguments approach domain boundaries. Under the simultaneous domination assumption, a continuous controller for the switched system is constructed. Furthermore, asymptotic tracking is achieved without violation of the constraint, and all closed-loop signals keep bounded, when a mild requirement on the initial condition is satisfied. Finally, a simulation example is provided to illustrate the effectiveness of the proposed results.
TL;DR: Using sophisticated bioengineering and molecular biology tools, it is reported that the binding of MSLN to MUC16 markedly enhances PC cell motility and invasion via the selective induction of matrix metalloproteinase (MMP)-7.
Abstract: Mesothelin Binding to CA125/MUC16 Promotes Pancreatic Cancer Cell Motility and Invasion via MMP-7 Activation
TL;DR: Comparisons show that the proposed new authentication protocol for wireless sensor networks using elliptic curves cryptography is more suitable for WSNs.
Abstract: User authentication in wireless sensor networks (WSNs) is a critical security issue due to their unattended and hostile deployment in the field. Since sensor nodes are equipped with limited computing power, storage, and communication modules, authenticating remote users in such resource-constrained environments is a paramount security concern. To overcome the weaknesses of Yeh et al.’s protocol, we proposed a new authentication protocol for wireless sensor networks using elliptic curves cryptography. The comparisons show that our protocol is more suitable for WSNs.
TL;DR: This paper analyzes the intrinsic features of the bit distributions, the high correlation among bit planes and other issues related to the bit information of an image, and proposes an expand-and-shrink strategy to shuffle the image with reconstructed permuting plane.
TL;DR: A new image encryption scheme integrated with compression simultaneously that first uses 2D hyper-chaos discrete nonlinear dynamic system to shuffle the plain image, and then applies Chinese remainder theorem to diffuse and compress the shuffled image, simultaneously.
Abstract: Hyper-chaos has more than one positive Lyapunov exponents and it has more complex dynamical characteristics than chaos Hence it becomes a better choice for secure image encryption schemes In this paper, we propose a new image encryption scheme integrated with compression simultaneously Specifically, we first use 2D hyper-chaos discrete nonlinear dynamic system to shuffle the plain image, and then we apply Chinese remainder theorem (well known in number theory) to diffuse and compress the shuffled image, simultaneously This new scheme can be used to change the plain image information drastically and compress the plain image with a given compression ratio k , which is most crucial in multimedia transmission Theoretical and experimental analyses both confirm the security and the validity of the proposed algorithm
TL;DR: The results from this study are potentially applicable to a range of perovskite-type mixed metal oxides useful in water splitting as well as other areas of heterogeneous photocatalysis.
Abstract: Potassium niobate (KNbO3) microcubes with orthorhombic and tetragonal phases were hydrothermally prepared and characterized by powder X-ray diffraction, nitrogen adsorption–desorption, micro-Raman spectroscopy, Fourier transform infrared spectroscopy, diffuse reflectance UV-visible spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, and high-resolution transmission electron microscopy. The photoreactivity of the as-prepared KNbO3 samples was evaluated regarding the hydrogen evolution from aqueous methanol under UV, and the results were compared with that of cubic KNbO3 microcubes. The photocatalytic reactivity was shown to be phase-dependent, following the order cubic > orthorhombic > tetragonal. Insight into the phase-dependent photocatalytic properties was gained by first-principles density functional calculations. The best photocatalytic performance of cubic KNbO3 is ascribed to it having the highest symmetry in the bulk structure and associated unique electronic structure. Further, the surface electronic structure plays a key role leading to the discrepancy in photoreactivity between orthorhombic and tetragonal KNbO3. The results from this study are potentially applicable to a range of perovskite-type mixed metal oxides useful in water splitting as well as other areas of heterogeneous photocatalysis.
TL;DR: In this paper, the effects and potential mechanisms of intranasal administration of desferrioxamine (DFO) on abnormal tau phosphorylation were investigated using amyloid precursor protein (APP) and presenilin 1 (PS1) double transgenic mouse brain as a model system.
TL;DR: A real-time safety early warning system to prevent accidents and improve safety management in underground construction, based on the “internet of things” (IoT) technology, that seamlessly integrates a fiber Bragg grating sensor system and a RFID-based labor tracking system.
TL;DR: The results indicate that the activation step not only creates a porous structure, but also introduces various phosphorus and oxygen functional groups to the surface of carbons to widen the potential window above the theoretical potential for the decomposition of water.
Abstract: Phosphorus-rich carbons (PCs) were prepared by phosphoric acid activation of waste coffee grounds in different impregnation ratios. PCs were characterized by nitrogen and carbon dioxide adsorption and X-ray photoelectron spectroscopy. The results indicate that the activation step not only creates a porous structure, but also introduces various phosphorus and oxygen functional groups to the surface of carbons. As evidenced by cyclic voltammetry, galvanostatic charge/discharge, and wide potential window tests, a supercapacitor constructed from PC-2 (impregnation ratio of 2), with the highest phosphorus content, can operate very stably in 1 M H2SO4 at 1.5V with only 18 % degradation after 10 000cycles at a current density of 5A g-1. Due to the wide electrochemical window, a supercapacitor assembled with PC-2 has a high energy density of 15Wh kg-1 at a power density of 75W kg -1. The possibility of widening the potential window above the theoretical potential for the decomposition of water is attributed to reversible electrochemical hydrogen storage in narrow micropores and the positive effect of phosphorus-rich functional groups, particularly the polyphosphates on the carbon surface. Rich pick-me-up! Waste coffee grounds are used to synthesize phosphorus-rich carbons (PCs), which show intriguing properties as electrode materials of an acidic supercapacitor. Large potentials can be applied, owing to the stabilizing effect of phosphorus on the carbon surface and reversible electrochemical hydrogen storage in pores of the PC. Copyright