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This paper examines the tracking property of nonlinear delayed multi-agent systems with impulsive effects. The strengths and locations of the stabilizing impulses, as well as the number of the controlled nodes are all assumed to be time-varying. Some sufficient criteria are established such that the considered system can exponentially track the dynamical reference state based on the given impulsive...
In this paper, we consider the design problem of a decentralized variable gain robust controller that provides practical tracking for a class of large-scale interconnected systems with mismatched uncertainties. Furthermore, we show that sufficient conditions for the existence of the proposed decentralized variable gain robust controller are reduced to the feasibility of linear matrix inequalities...
In this paper, the non-fragile finite-time tracking control problem is addressed for a class of uncertain linear systems with controller multiplicative coefficient variations. An adaptive control strategy is constructed to ensure that the system tracks a time-varying target orbit. The relationship of the bound of tracking errors and the size of uncertainties and controller multiplicative coefficient...
Although most companies operate a firewall to protect their information assets, they have difficulties in identifying the control conditions of firewalls. This study proposes an analysis tool to visualize segment-based firewall rules to facilitate verification of the current control conditions. The proposed visualization tool analyzes the current control conditions of packets automatically, thereby...
Cyber network analysts follow complex processes in their investigations of potential threats to their network. Much research is dedicated to providing automated decision support in the effort to make their tasks more efficient, accurate, and timely. Support tools come in a variety of implementations from machine learning algorithms that monitor streams of data to visual analytic environments for exploring...
A Lyapunov-based construction of a predefined-time stabilizing function (a function that stabilizes a system in fixed-time with settling time as function of the controller parameters) for scalar systems is considered in this paper. The constructed function involves the inverse incomplete gamma function, causing this function to be semi-global, i.e., the domain of definition of the function can be...
We study the problem of approximating the partition function of the ferromagnetic Ising model in graphs and hypergraphs. Our first result is a deterministic approximation scheme (an FPTAS) for the partition function in bounded degree graphs that is valid over the entire range of parameters β (the interaction) and λ (the external field), except for the case |λ|=1 (the...
In the set disjointess problem, we have k players, each with a private input X^i ⊆ [n], and the goal is for the players to determine whether or not their sets have a global intersection. The players communicate over a shared blackboard, and we charge them for each bit that they write on the board.We study the trade-off between the number of interaction rounds we allow the players, and the...
We give a deterministic \tilde{O}(\log n)-space algorithm for approximately solving linear systems given by Laplacians of undirected graphs, and consequently also approximating hitting times, commute times, and escape probabilities for undirected graphs. Previously, such systems were known to be solvable by randomized algorithms using O(\log n) space (Doron, Le Gall, and Ta-Shma, 2017) and hence by...
In the minimum planarization} problem, given some n-vertex graph, the goal is to find a set of vertices of minimum cardinality whose removal leaves a planar graph. This is a fundamental problem in topological graph theory. We present a \log^{O(1)} n-approximation algorithm for this problem on general graphs with running time n^{O(\log n/\log\log n)}. We also obtain a O(n^≥)-approximation...
We show that the perfect matching problem in general graphs is in Quasi-NC. That is, we give a deterministic parallel algorithm which runs in O(\log^3 n) time on n^{O(\log^2 n)} processors. The result is obtained by a derandomization of the Isolation Lemma for perfect matchings, which was introduced in the classic paper by Mulmuley, Vazirani and Vazirani [1987] to obtain a Randomized NC algorithm...
In a non-uniform Constraint Satisfaction problem CSP(Γ), where G is a set of relations on a finite set A, the goal is to find an assignment of values to variables subject to constraints imposed on specified sets of variables using the relations from Γ. The Dichotomy Conjecture for the non-uniform CSP states that for every constraint language \Gm the problem CSP(Γ)...
More than 25 years ago, inspired by applications in computer graphics, Chazelle \etal (FOCS 1991) studied the following question: Is it possible to cut any set of n lines or other objects in \Reals^3 into a subquadratic number of fragments such that the resulting fragments admit a depth order? They managed to prove an O(n^{9/4}) bound on the number of fragments, but only for the very special case...
For odd integers p ≥ 1 (and p = ∞), we show that the Closest Vector Problem in the ℓp norm (CVP_p) over rank n lattices cannot be solved in 2^(1-≥) n time for any constant ≥ 0 unless the Strong Exponential Time Hypothesis (SETH) fails. We then extend this result to almost all values of p ≥ 1, not including the even integers. This comes...
Clustering is a classic topic in optimization with k-means being one of the most fundamental such problems. In the absence of any restrictions on the input, the best known algorithm for k-means with a provable guarantee is a simple local search heuristic yielding an approximation guarantee of 9+≥ilon, a ratio that is known to be tight with respect to such methods.We overcome this barrier...
We give a quantum algorithm for solving semidefinite programs (SDPs). It has worst-case running time n^{\frac{1}{2}} m^{\frac{1}{2}} s^2 \poly(\log(n), \log(m), R, r, 1/δ), with n and s the dimension and row-sparsity of the input matrices, respectively, m the number of constraints, δ the accuracy of the solution, and R, r upper bounds on the size of the optimal primal and dual...
The Rabi Hamiltonian is characterized by: Ω — the frequency of the transition between the atomic levels, ω — the oscillator frequency, and λ — the coupling between these two subsystems. Even though the Rabi Hamiltonian is quite simple its complete solution is rather complicated and simpler Hamiltonian forms are needed for various regimes of parameters. In the ultra-strong coupling regime of the Rabi...
The accurate and fast detection of the grid voltage attributes (e.g. frequency and amplitude) are gaining more attention in microgrids due to the new stringent amendments to the microgrid standards. In this paper, two novel observer based techniques are introduced; one for estimating the frequency and another for the amplitude of the grid voltage. The proposed observer techniques offer superior performance...
Representing reality in computer graphics requires simulating the appearance of real-world materials. Bidirectional Reflectance Distribution Functions (BRDFs) are commonly used to perform this task, as they represent the appearance of a material through the quotient between the reflected radiance and the incoming irradiance at this point. Acquiring the BRDF of a real material is an expensive task...
In this study, improved antlion optimization algo-rithm (IALO) is presented. The antlion optimization algorithm (ALO) is an heuristic optimization algorithm based on modeling random walks of ants and hunting ants by antlions. The random walk model of ALO and the IALO revealed by improvements in the selection method have been tested with benchmark functions with different characteristics from the literature...
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