Efficient Algorithm for ECG Coding Research Papers (original) (raw)

2025, Mathematical and computational applications

An image segmentation technique based on fuzzy sets for ultrasonic B-scans is presented. The fuzzy c-means algorithm is adapted to B-scan images. The classes constituting a region are obtained through fuzzy partitioning based on local statistics information. The perfonnance of the method is tested on phantom and tissue images and the results are presented.

2025, Graphics Interface

Ray tracers that render CSG models should consider issues of regularization and numerical accuracy. The special case of rays originating on surfaces (shadow probes, reflections, and refractions) present a regularization problem that is significant-even in ray tracers which are not explicitly based on the CSG scheme. An analysis of this problem yields a better solution than the epsilon tests incorporated in most ray tracers. † Formal treatments like Tilove's are based on the concept of classification, rather than intersection. The classification of a ray R with respect to a solid S is a partitioning of the ray into RinS, RonS, and RoutS, which are points inside S, on its boundary, or outside the solid. We will simply discuss the problem in terms of ray intersection.

2025, International Conference in Cognitive Systems

This paper presents a new Parallel Algorithm for computing a Longest Common Subsequence in Multiple DNA Sequences. It uses a heuristic approach. Although a lot of research has been carried out to find LCS from the two or more given sequences of Protein, DNA, RNA etc, but not many parallel methods exists for finding LCS from multiple sequences. Normally in existing algorithms the time complexity for finding the LCS increases linearly with the increase in Sequences. This is an attempt to given an effective Parallel algorithm to find LCS from any given number of DNA sequences. Significance of this algorithm is that time complexity does not increase linearly with the increase in the number of sequences. However algorithm can also be applied to Protein sequences with the same effectiveness, though the requirement of processors will go up.

2025, Proceedings - SBCCI 2008: 21st Symposium on Integrated Circuits and Systems Design

This article addresses the multiplication of one data sample with multiple constants using addition/subtraction and shift operations, i.e., the multiple constant multiplications (MCM) operation. In the last two decades, many efficient algorithms have been proposed to implement the MCM operation using the fewest number of addition and subtraction operations. However, due to the NP-hardness of the problem, almost all the existing algorithms have been heuristics. The main contribution of this article is the proposal of an exact depth-first search algorithm that, using lower and upper bound values of the search space for the MCM problem instance, finds the minimum solution consuming less computational resources than the previously proposed exact breadth-first search algorithm. We start by describing the exact breadth-first search algorithm that can be applied on real mid-size instances. We also present our recently proposed approximate algorithm that finds solutions close to the minimum and is able to compute better bounds for the MCM problem. The experimental results clearly indicate that the exact depth-first search algorithm can be efficiently applied to large size hard instances that the exact breadth-first search algorithm cannot handle and the heuristics can only find suboptimal solutions.

2025, Norchip - 26th Norchip Conference, Formal Proceedings

This paper addresses the multiplication of one data sample with multiple constants using addition/subtraction and shift operations, i.e., the multiple constant multiplications (MCM) problem. The MCM problem finds itself and its variants in many applications, such as digital finite impulse response (FIR) filters, linear signal transforms, and computer arithmetic. Although many efficient algorithms have been proposed to implement the MCM using the fewest number of operations, due to the NP-hardness of the problem, they have been heuristics, i.e., they cannot guarantee the minimum solution. In this work, we propose an exact algorithm based on the breadth-first search that finds the minimum number of operations solution of midsize MCM instances in a reasonable time. The proposed exact algorithm has been tested on a set of instances including FIR filter and randomly generated instances, and compared with the previously proposed efficient heuristics. It is observed from the experimental results that, even though the previously proposed heuristics obtain similar results with the minimum number of operations solutions, there are instances for which the exact algorithm finds better solutions than the prominent heuristics.

2025, Proceedings of the 43rd annual conference on Design automation - DAC '06

In this paper, we propose an exact algorithm for the problem of area optimization under a delay constraint in the synthesis of multiplierless FIR filters. To the best of our knowledge, the method presented in this paper is the only exact algorithm designed for this problem. We present the results of the algorithm on real-sized filter instances and compare with an improved version of a recently proposed exact algorithm designed for the minimization of area. We show that in many cases delay can be minimized without any area penalty. Additionally, we describe two approximate algorithms that can be applied to instances which cannot be solved, or take too long, with the exact algorithm. We show that these algorithms find similar solutions to the exact algorithm in less CPU time.

2025, Biomimetics

This study proposes an adaptable, bio-inspired optimization algorithm for Multi-Agent Space Exploration. The recommended approach combines a parameterized Aquila Optimizer, a bio-inspired technology, with deterministic Multi-Agent Exploration. Stochastic factors are integrated into the Aquila Optimizer to enhance the algorithm’s efficiency. The architecture, called the Multi-Agent Exploration–Parameterized Aquila Optimizer (MAE-PAO), starts by using deterministic MAE to assess the cost and utility values of nearby cells encircling the agents. A parameterized Aquila Optimizer is then used to further increase the exploration pace. The effectiveness of the proposed MAE-PAO methodology is verified through extended simulations in various environmental conditions. The algorithm viability is further evaluated by comparing the results with those of the contemporary CME-Aquila Optimizer (CME-AO) and the Whale Optimizer. The comparison adequately considers various performance parameters, such...

2025, 2005 NORCHIP

This paper presents a new approach to implement Reed-Muller Universal Logic Module (RM-ULM) networks with reduced delay and hardware for synthesizing logic functions given in Reed-Muller (RM) form. Replication of single control line RM-ULM is used as the only design unit for defining any logic function. An algorithm is proposed that does exhaustive branching to reduce the number of levels and modules required to implement any logic function in RM form. This approach attains a reduction in delay, and power over other implementations of functions having large number of variables.

2025, Proceedings of the fourth ACM SIGPLAN symposium on Principles and practice of parallel programming - PPOPP '93

We present a solution to the reaching definitions problem for programs with explicit lexicully specified parallel constructs, such as cobeginicoend orparallel.sections, hothwith and without explicit synchronization operations, such as Post, Wait or Advance. The reaching definitiona information for sequential programs is used to solve many standard optimization problems. ln parallel programs, th~information can also be used to explicitly direct communication and data ownership. Although work has been done on analyzing parallel programs to detect data races, little work has been done on optimizing such programs. We show how the memory consistency model specified by an explicitly parallel programming language can influence the complexity of the reaching definitions problem. By selecting the "weakest" memory consistency semantics, we can efficiently solve the reaching definitions problem for correct programs,

2025, Journal of Information Processing

Equation ( ) may be proved by inspection of (18), while (21) may be demonstrated by expanding the logarithm in (17) into a Taylor series and retaining only the first two terms. Equations ( ) and ( ) show that as the number of accesses becomes immaterial, one should use very small resident and overflow records to reduce the total storage volume. Substituting ( ) and ( ) into eq. ( ), we get V* ~, R.s/a + R.s. (a --1)/a = R.s, (23) which is the absolute minimal storage volume needed, without any "overhead" added by the storage method.

2025, IEEE Transactions on Acoustics, Speech, and Signal Processing

An alternative form of the fast Fourier transform @ET) is developed. The new algorithm has the peculiarity that none of the multiplying constants required are complex-most are pure imaginary.

2025, The Journal of the Acoustical Society of America

This paper presents a statistically and computationally efficient algorithm for direction finding of a single far-field source using a multi-sensor array. The algorithm extracts the azimuth and elevation angles directly from the estimated time delays between the array elements. Hence, it is referred to herein as the time delay direction finding (TDDF) algorithm. An asymptotic performance analysis, using a small error assumption, is conducted. For any 1-D and 2-D array configurations, it is shown that the TDDF algorithm achieves the Cramer Rao lower bound (CRLB) for the azimuth and elevation estimates provided that the noise is Gaussian and spatially uncorrected and that the time delay estimator achieves the CRLB as well. Moreover, with the suggested algorithm no constraints on the array geometry are required. For the general 3-D case the algorithm does not achieve the CRLB for a general array. However, it is shown that for array geometries which obey certain constraints the CRLB is ...

2025, arXiv (Cornell University)

Operations research is neither a method nor a technique; it is or is becoming a science and as such is defined by a combination of the phenomena it studies.

2025

The iris recognition technology is the most accurate, fast and less invasive one compared to other biometric techniques using for example fingerprints, face, retina, hand geometry, voice or signature patterns. The system developed in this study has the potential to play a key role in areas of high-risk security and can enable organizations with means allowing only to the authorized personnel a fast and secure way to gain access to such areas. The paper aim is to perform the iris region detection and iris inner and outer boundaries localization. The system was implemented on windows platform using Visual C# programming language. It is easy and efficient tool for image processing to get great performance accuracy. In particular, the system includes two main parts. The first is to preprocess the iris images by using Canny edge detection methods, segments the iris region from the rest of the image and determine the location of the iris boundaries by applying Hough transform. The propose...

2025, Zenodo (CERN European Organization for Nuclear Research)

2025

This paper introduces a new method which, given an arbitrary Boolean function and specified set of (function hazardfree) input transitions, determines if any hazard-free multilevel logic implementation exists. The algorithm is based on iterative decomposition, using disjunction and inversion. Earlier approaches by Nowick/Dill and Theobald/Nowick have been proposed to determine if a hazard-free two-level logic implementation exists. However, it is well-known that the effects of multi-level transformations are quite complex: since they can both decrease and increase logic hazards in a given circuit. In this paper, a method is proposed to solve the hazard-free multi-level existence problem. The method is proven to be both sound and complete for a large class of multi-level implementations. A novel contribution is to show that, if any hazard-free multi-level solution exists, then a hazard-free solution always exists using only 3 logic levels, in a 3-level NAND or OR-AND-OR structure. Moreover, in this case, it is shown there always exists a unique canonical hazard-free 3-level implementation.

2025, International Conference on Computer Aided Design

The time separation of events (TSE) problem is that of finding the maximum and minimum separation between the times of occurrence of two events in a concurrent system. It has applications in the performance analysis, optimization and verification of concurrent digital systems. This paper introduces an efficient polynomial-time algorithm to give exact bounds on TSE's for choice-free concurrent systems, whose operational semantics obey the max-causality rule. A choicefree concurrent system is modeled as a strongly-connected marked graph, where delays on operations are modeled as bounded intervals with unspecified distributions. While previous approaches handle acyclic systems only, or else require graph unfolding until a steady-state behavior is reached, the proposed approach directly identifies and evaluates the asymptotic steady-state behavior of a cyclic system via a graph-theoretical approach. As a result, the method has significantly lower computational complexity than previously-proposed solutions. A prototype CAD tool has been developed to demonstrate the feasibility and efficacy of our method. A set of experiments have been performed on the tool as well as two existing tools, with noticeable improvement on runtime and accuracy for several examples. This paper addresses the problem of finding the maximum and minimum time separation of events (TSE) in concurrent systems. A concurrent system is considered as a set of interacting processes which communicate through channels. When a process initiates a communication with one or more other processes, it waits for all parties to respond before it proceeds. Such operating semantics is said to obey the max-causality rule, or to operate under the max timing constraint. This model can be applied to problems in a wide range of domains. A "process" can correspond to the transition of a signal at the circuit level, or to a partition of functional units at the system level. Several delay models have been used in modelling these systems. A "stochastic model" is often used for the performance analysis of these systems , . However, for verification, a "bounded-delay" model, where the computation time of each process is assumed to be bounded below (min) and above (max) by non-negative real numbers, with no distribution specified, is much more useful. In the special case where the upper and lower bounds of the computation time are identical, a "fixed-delay" model is said to be used. This paper targets concurrent systems under a bounded-delay model. To make the problem amenable for analysis, the system is assumed to be decision-free; such systems can be modeled by marked graphs , which are commonly used to capture concurrent behavior. The TSE problem for bounded-delay systems has applications to performance analysis, optimization of verification of concurrent systems. In this case, while it is generally not possible to provide accurate average case performance metrics, since no delay distribution is given, one can usefully predict best case and worst case performance metrics, such as system throughput. For the restricted case of fixed-delay systems, TSE also becomes a performance measure of the system, as in this case the distribution of the delay is trivially known (i.e. exactly one delay value per event in the system).

2025, SIAM Journal on Discrete Mathematics

Reconfigurable chips are fabricated with redundant elements that can be used to replace the faulty elements. The fault cover problem consists of finding an assignment of redundant elements to the faulty elements such that all of the faults are repaired. In reconfigurable chips that consist of arrays of elements, redundant elements are configured as spare rows and spare columns. This paper considers the problem in which a chip contains several replicates of a heterogeneous array, one or more sets of spare rows, and one or more sets of spare columns. Each set of spare rows is identical to the set of rows in the array, and each set of spare columns is identical to the set of columns in the array. Specifically, an ith spare row can only be used to replace an ith row of an array, and similarly with spare columns. Repairing the chip reduces to finding a cover for the faults in each of the arrays. These covers must be disjoint; that is, a particular spare row or spare column can be used in the cover of at most one array. Results are presented for three fault cover problems that arise under these conditions. Key words, reconfigurable chips, fault covers AMS(MOS) subject classification. 94C15 1. Introduction. As chip density increases, the likelihood of fabrication defects on chips also increases. Maintaining an acceptable yield in chip production requires the capability to repair defective chips. To this end, reconfigurable chips are fabricated with redundant elements that can be used to replace faulty elements. The fault cover problem consists of finding an assignment of redundant elements to the faulty elements such that all of the faulty elements are replaced.

2025, IEEE Transactions on Parallel and Distributed Systems

Absfrucf-This paper presents efficient algorithms that implement one-tbmany, or multicast, communication in wormholerouted torus networks. By exploiting the properties of the switching technology and the use of virtual channels, a minimumtime multicast algorithm is presented for n-dimensional torus networks that use deterministic, dimension-ordered routing of unicast messages. The algorithm can deliver a multicast message to m -1 destinations in hog2 ml nkage-passing steps, while avoiding contention among the constituent unicast messages. Performance results of a simulation study on torus networks with up to 4096 nodes are also given.

2025, IEEE Transactions on Parallel and Distributed Systems

Multicast communication, in which the same message is delivered from a source node to an arbitrary number of destination nodes, is being increasingly demanded in parallel computing. System supported multicast services can potentially o er improved performance, increased functionality, and simpli ed programming, and may in turn be used to support various higher-level operations for data movement and global process control. This paper presents e cient algorithms to implement multicast communication in wormhole-routed direct networks, in the absence of hardware multicast support, by exploiting the properties of the switching technology. Minimum-time multicast algorithms are presented for n-dimensional meshes and hypercubes that use deterministic, dimension-ordered routing of unicast messages. Both algorithms can deliver a multicast message to m ? 1 destinations in dlog 2 me message passing steps, while avoiding contention among the constituent unicast messages. Performance results of implementations on a 64-node nCUBE-2 hypercube and a 168-node Symult 2010 2D mesh are given.

2025, Lecture Notes in Computer Science

Model checking is an automatic approach for the verification of systems. Explicit states model checking applies a search algorithm (e.g., depth or breadth first search) to the state space of the verified system. In concurrent systems, and in particular in communication protocols, the number of states can grow exponentially with the number of independent components (processes). There are many different methods that attempt to automatically reduce the number of checked states. Such methods show encouraging results, but often still fail to reduce the number of states required for the verification to become manageable. We propose here the use of code annotation in order to control the verification process and reduce the number of states searched. Our extension of the C programming language allows the user to put into the code instructions that are executed by the model checker during the verification. With the new language construct, we may exploit additional insight that the verifier may have about the checked program in order to limit the search. We describe our implementation and present some experimental results.

2025, Proceedings of the First International Conference on Computer Vision Theory and Applications

Object segmentation from a video stream is an essential task in video processing and forms the foundation of scene understanding, object-based video encoding (e.g. MPEG4), and various surveillance and 2D-topseudo-3D conversion applications. The task is difficult and exacerbated by the advances in video capture and storage. Increased resolution of the sequences requires development of new, more efficient algorithms for object detection and segmentation. The paper presents a novel neural network based approach to background modeling for motion based object segmentation in video sequences. The proposed approach is designed to enable efficient, highly-parallelized hardware implementation. Such a system would be able to achieve real time segmentation of high-resolution sequences.

2025, Journal of the ACM

We provide data strutures that maintain a graph as edges are inserted and deleted, and keep track of the following properties with the following times: minimum spanning forests, graph connectivity, graph 2-edge connectivity, and bipartiteness in time O ( n 1/2 ) per change; 3-edge connectivity, in time O ( n 2/3 ) per change; 4-edge connectivity, in time O ( n α( n )) per change; k -edge connectivity for constant k , in time O ( n log n ) per change;2-vertex connectivity, and 3-vertex connectivity, in the O ( n ) per change; and 4-vertex connectivity, in time O ( n α( n )) per change. Further results speed up the insertion times to match the bounds of known partially dynamic algorithms. All our algorithms are based on a new technique that transforms an algorithm for sparse graphs into one that will work on any graph, which we call sparsification.

2025, Proceedings of the 12th International Conference on Security and Cryptography

The main problem in designing effective code obfuscation is to guarantee security. State of the art obfuscation techniques rely on an unproven concept of security, and therefore are not regarded as provably secure. In this paper, we undertake a theoretical investigation of code obfuscation security based on Kolmogorov complexity and algorithmic mutual information. We introduce a new definition of code obfuscation that requires the algorithmic mutual information between a code and its obfuscated version to be minimal, allowing for controlled amount of information to be leaked to an adversary. We argue that our definition avoids the impossibility results of Barak et al. and is more advantageous then obfuscation indistinguishability definition in the sense it is more intuitive, and is algorithmic rather than probabilistic.

2025

This paper describes new and efficient algorithms for learning deterministic finite automata. Our approach is primarily distinguished by two features: (1) the adoption of an average-case setting to model the ``typical'' labeling of a finite automaton, while retaining a worst-case model for the underlying graph of the automaton, along with (2) a learning model in which the learner is not provided with the means to experiment with the machine, but rather must learn solely by observing the automaton's output behavior on a random input sequence. The main contribution of this paper is in presenting the first efficient algorithms for learning nontrivial classes of automata in an entirely passive learning model. We adopt an on-line learning model in which the learner is asked to predict the output of the next state, given the next symbol of the random input sequence; the goal of the learner is to make as few prediction mistakes as possible. Assuming the learner has a means of resetting the target machine to a fixed start state, we first present an efficient algorithm that article no. IC972648 23

2025, Conference on Learning Theory

We show that randomly generated monotone c log(n)-DNF formula can be learned exactly in probabilistic polynomial time. Our notion of randomly generated is with respect to a uniform distribution. To prove this we identify the class of well behaved monotone c log(n)-DNF formulae, and show that almost every monotone DNF formula is well-behaved, and that there exists a probabilistic Turing machine that exactly learns all well behaved monotone c log(n)-DNF formula.

2025, Physical Review B

The Chern-Hopf insulator is an unconventional three-dimensional topological insulator with a bulk gap and gapless boundary states without protection from global discrete symmetries. This study investigates its fate in the presence of disorder. We find it stable up to moderate disorder by analyzing the surface states and the zero energy bulk density of states using large-scale numerical simulation and the self-consistent Born approximation. The disordered Chern-Hopf insulator shows reentrant behavior: the disorder initially enhances the topological phase before driving it across an insulator-diffusive metal transition. We examine the associated critical exponents via finite-size scaling of the bulk density of states, participation entropy, and two-terminal conductance. We estimate the correlation length exponent ν ≃ 1.0(1), consistent with the clean two-dimensional Chern universality and distinct from the integer quantum Hall exponent.

2025, Analytical Assessment of Auxiliary Cache Utility Data Structures for Vector Databases and LLM Retrieval Pipelines

This paper presents an analytical framework for
evaluating auxiliary cache utility data structures in vector
databases and local large language model (LLM) retrieval
pipelines. While frequency-based caching policies such as
TinyLFU are well-established in mature systems, the incremental
value of a dedicated auxiliary cache layer that sits between
application logic and existing caching mechanisms remains an
open question. We develop a formal mathematical model for
analyzing cache utility and present a structured assessment
methodology examining architectural trade-offs. Our analysis
encompasses system complexity, maintenance burden, and cache
coherence challenges against potential performance benefits. We
systematically compare architectural approaches across different
deployment scenarios and query workloads, identifying conditions
where auxiliary caches might provide meaningful benefits beyond
existing mechanisms. Rather than making empirical claims
that would require extensive benchmarking, we contribute a
decision framework that system architects can apply to their
specific contexts. We conclude by identifying key experimental
metrics and validation approaches that would be necessary
to quantitatively evaluate auxiliary cache implementations in
production environments.

2025, Queueing Systems - Theory and Applications

A threshold start-up policy is appealing for manufacturing (service) facilities that incur a cost for keeping the machine (server) on, as well as for each restart of the server from its dormant state. Analysis of single product (customer) systems operating under such a policy, also known as the N-policy, has been available for some time. This article develops mathematical analysis

2025, 2011 Proceedings IEEE INFOCOM

As the physical link speeds grow and the size of routing table continues to increase, IP address lookup has been a challenging problem at routers. There have been growing demands in achieving high-performance IP lookup costeffectively. Existing approaches typically resort to specialized hardwares, such as TCAM. While these approaches can take advantage of hardware parallelism to achieve high-performance IP lookup, they also have the disadvantage of high cost. This paper investigates a new way to build a cost-effective IP lookup scheme using graphics processor units (GPU). Our contribution here is to design a practical architecture for high-performance IP lookup engine with GPU, and to develop efficient algorithms for routing prefix update operations such as deletion, insertion, and modification. Leveraging GPU's many-core parallelism, the proposed schemes addressed the challenges in designing IP lookup at GPU-based software routers. Our experimental results on real-world route traces show promising gains in IP lookup and update operations.

2025, Lecture Notes in Computer Science

It has been shown that many kernel methods can be equivalently formulated as minimal enclosing ball (MEB) problems in a certain feature space. Exploiting this reduction, efficient algorithms to scale up Support Vector Machines (SVMs) and other kernel methods have been introduced under the name of Core Vector Machines (CVMs). In this paper, we study a new algorithm to train SVMs based on an instance of the Frank-Wolfe optimization method recently proposed to approximate the solution of the MEB problem. We show that, specialized to SVM training, this algorithm can scale better than CVMs at the price of a slightly lower accuracy.

2025, Proceedings of the 36th international symposium on Symbolic and algebraic computation

We present a new exact subdivision algorithm Ceval for isolating the complex roots of a square-free polynomial in any given box. It is a generalization of a previous real root isolation algorithm called Eval. Under suitable conditions, our approach is applicable for general analytic functions. Ceval is based on the simple Bolzano Principle and is easy to implement exactly. Preliminary experiments have shown its competitiveness. We further show that, for the "benchmark problem" of isolating all roots of a square-free polynomial with integer coefficients, the asymptotic complexity of both algorithms Eval and Ceval matches (up a logarithmic term) that of more sophisticated real root isolation methods which are based on Descartes' Rule of Signs, Continued Fraction or Sturm sequences. In particular, we show that the tree size of Eval matches that of other algorithms. Our analysis is based on a novel technique called δ-clusters from which we expect to see further applications.

2025, Linear Algebra and its Applications

In this paper we address the problem of computing the permanent of (0,1)-circulant matrices. We investigate structural properties of circulant matrices, showing that (i) if they are dense enough, then they contain large arbitrary submatrices, and (ii) if they are very sparse, then they are not too ``far'' from convertible matrices. Building upon (ii), we then develop an ecient algorithm, which allows us to compute permanents of very sparse circulants of size up to 200.

2025, Journal of the ACM

We present a model that enables us to analyze the running time of an algorithm on a computer with a memory hierarchy with limited associativity, in terms of various cache parameters. Our cache model, an extension of Aggarwal and Vitter's I/O model, enables us to establish useful relationships between the cache complexity and the I/O complexity of computations. As a corollary, we obtain cache-efficient algorithms in the single-level cache model for fundamental problems like sorting, FFT, and an important subclass of permutations. We also analyze the average-case cache behavior of mergesort, show that ignoring associativity concerns could lead to inferior performance, and present supporting experimental evidence.We further extend our model to multiple levels of cache with limited associativity and present optimal algorithms for matrix transpose and sorting. Our techniques may be used for systematic exploitation of the memory hierarchy starting from the algorithm design stage, and ...

2025, The Journal of Supercomputing

Multiple memory models have been proposed to capture the effects of memory hierarchy culminating in the I-O model of Aggarwal and Vitter [?]. More than a decade of architectural advancements have led to new features that are not captured in the I-O model -most notably the prefetching capability. We propose a relatively simple Prefetch model that incorporates data prefetching in the traditional I-O models and show how to design optimal algorithms that can attain close to peak memory bandwidth. Unlike (the inverse of) memory latency, the memory bandwidth is much closer to the processing speed, thereby, intelligent use of prefetching can considerably mitigate the I-O bottleneck. For some fundamental problems, our algorithms attain running times approaching that of the idealized Random Access Machines under reasonable assumptions. Our work also explains more precisely the significantly superior performance of the I-O efficient algorithms in systems that support prefetching compared to ones that do not.

2025

This paper addresses the problem of distributively electing a leader in both synchronous and asynchronous complete networks. In the synchronous case, we prove a lower bound of ft(n'logn) on the message complexity. We also prove that any message-optimal synchronous algorithm requires ~(log n) time. In proving these bounds we do not restrict the type of operations performed by nodes. The bounds thus apply to general algorithms and not just to comparison based algorithms. A simple algorithm which achieves these bounds is presented. In the asynchronous case, we present a sequence of three simple and efficient algorithms, each of which is an improvement on the previous. The third algorithm has time complexity O(n) and message complexity 2.n.logn+O(n), thus improving the time complexity of the previous best algorithm [Kor84] by a factor of logn. Permission to copy without fee all or part of this material is granted provided that the copies are not made or distributed for direct commercial advantage, the ACM copyright notice and the title of the publication and its date appear, and notice is given that copying is by permission of the Association for Computing Machinery. To copy otherwise, or to republish, requires a fee and/or specific permission.

2025, ACM Transactions on Internet Technology

Web caching is an important technology for improving the scalability of Web services. One of the key problems in coordinated enroute Web caching is to compute the locations for storing copies of an object among the enroute caches so that some specified objectives are achieved. In this article, we address this problem for tree networks, and formulate it as a maximization problem. We consider this problem for both unconstrained and constrained cases. The constrained case includes constraints on the cost gain per node and on the number of object copies to be placed. We present dynamic programming-based solutions to this problem for different cases and theoretically show that the solutions are either optimal or convergent to optimal solutions. We derive efficient algorithms that produce these solutions. Based on our mathematical model, we also present a solution to coordinated enroute Web caching for autonomous systems as a natural extension of the solution for tree networks. We impleme...

2025, The Journal of the Acoustical Society of America

The underwater acoustic normal modes of multichannel environments may exhibit closely spaced eigenvalues that require a fine horizontal wave-number sample in models based on the Airy equation. Also, for broadband applications the maximum frequency difference that permits accurate interpolation is limited by the frequency difference of the modal depth functions. A straightforward and numerically efficient algorithm to construct a monotonic depth-dependent phase using the properties of the Airy functions is presented that significantly reduces the computational burdens imposed by these constraints. The total phase change of a mode across the depth of the waveguide gives the mode number, modulo π, which is essential in adiabatic normal-mode calculations for range variable environments because the acoustic field must be propagated from one environment to the next mode by mode. [Work supported by the Advanced Surveillance and Prediction System (ASAPS) Program of the Space and Naval Warfa...

2025

Since university timetabling is commonly classified as a combinatorial optimisation problem, researchers tend to use optimisation approaches to reach the optimal timetable solution. Meta-heuristic algorithms have been presented as effective solutions as proven on their leverage over the last decade. Extensive literature studies have been published until today. However, a comprehensive systematic overview is missing. Therefore, this mapping study aimed to provide an organised view of the current state of the field and comprehensive awareness of the meta-heuristic approaches, by conducting meta-heuristic for solving university timetabling problems. In addition, the mapping study tried to highlight the intensity of publications over the last years, spotting the current trends and directions in the field of solving university timetabling problems, as well as having the work to provide guidance for future research by indicating the gaps and open questions to be fulfilled. Primary studies on mapping study that have been published in the last decade from 2009 until the first quarter of 2020, which consist of 131 publications, were selected as a benchmark for future research to solve university timetabling problems using meta-heuristic algorithms. The majority of the articles based on the publication type are hybrid methods (32%), in which the distribution of meta-heuristic algorithms the hybrid algorithms represent the higher application (31%). Likewise, the majority of the research is solution proposals (66%). The result of this study confirmed the efficiency and intensive application of the meta-heuristic algorithms in solving university timetabling problems, specifically the hybrid algorithms. A new trend of meta-heuristic algorithms such as grey wolf optimiser, cat swarm optimisation algorithm, Elitist self-adaptive step-size search and others with high expectations for reliable and satisfying results can be proposed to fill this gap.

2025, arXiv (Cornell University)

Assembling genomic sequences from a set of overlapping reads is one of the most fundamental problems in computational biology. Algorithms addressing the assembly problem fall into two broad categoriesbased on the data structures which they employ. The first class uses an overlap/string graph and the second type uses a de Bruijn graph. However with the recent advances in short read sequencing technology, de Bruijn graph based algorithms seem to play a vital role in practice. Efficient algorithms for building these massive de Bruijn graphs are very essential in large sequencing projects based on short reads. In [1], an O(n/p) time parallel algorithm has been given for this problem. Here n is the size of the input and p is the number of processors. This algorithm enumerates all possible bi-directed edges which can overlap with a node and ends up generating Θ(nΣ) messages. In this paper we present a Θ(n/p) time parallel algorithm with a communication complexity equal to that of parallel sorting and is not sensitive to Σ. The generality of our algorithm makes it very easy to extend it even to the out-of-core model and in this case it has an optimal I/O complexity of Θ( n log(n/B) B log(M/B) ). We demonstrate the scalability of our parallel algorithm on a SGI/Altix computer. A comparison of our algorithm with that of [1] reveals that our algorithm is faster. We also provide efficient algorithms for the bi-directed chain compaction problem.

2025, Journal of Computational Physics

H-polarized electromagnetic fields of the Bloch form. Various theoretical methods for 2D photonic crystals were de-Using analytical methods we develop an accurate and efficient algorithm for computation of the spectrum and eigenmodes for a veloped in for sinusoidally and rectangularly modu-2D photonic crystal which comprises a periodic array of parallel lated dielectric constants and in 20] for a periodic array rods of air of a square cross section embedded in a background of parallel dielectric rods of circular cross section whose lossless medium of higher dielectric constant. The numerical analyintersections with perpendicular planes form a triangular sis of dependence of the spectral bands on the parameters of the or square lattice. Similar structures were studied theoreti-2D photonic crystal is carried out. It gives a reliable base for the optimal design of 2D photonic crystals. ᮊ 1997 Academic Press cally and experimentally in . All those results (see also 22]) suggest the possibility of a gap (or pseudogap) regime for some two-component periodic di- 1 The U.S. Government's right to retain a nonexclusive royalty-free ⌿ and its partial derivatives associated with the discontinulicense in and to the copyright covering this paper, for governmental purposes, is acknowledged. ity of the dielectric constant (x). A reasonable way to 585

2025, Lecture Notes in Computer Science

Graded-CTL is an extension of CTL with graded quantifiers which allow to reason about either at least or all but any number of possible futures. In this paper we show an extension of the NuSMV model-checker implementing symbolic algorithms for graded-CTL model checking. The implementation is based on the CUDD library, for BDDs and ADDs manipulation, and includes also an efficient algorithm for multiple counterexamples generation. 1 For better readability, we call this extension Graded-CTL NuSMV.

2025, arXiv (Cornell University)

For many real-life Bayesian networks, common knowledge dictates that the output established for the main variable of interest increases with higher values for the observable variables. We define two concepts of monotonicity to capture this type of knowledge. We say that a network is isotone in distribution if the probability distribution computed for the output variable given specific observations is stochastically dominated by any such distribution given higher-ordered observations; a network is isotone in mode if a probability distribution given higher observations has a higher mode. We show that establishing whether a network exhibits any of these properties of monotonicity is coNP PP -complete in general, and remains coNP-complete for polytrees. We present an approximate algorithm for deciding whether a network is monotone in distribution and illustrate its application to a real-life network in oncology. Invasion-wall no yes Necrosis no yes Gastro-necrosis no yes X-fistula no yes no yes CT-organs no yes Bronchoscopy no yes Lapa-diaphragm no yes CT-lungs no yes X-lungs no yes Metas-lungs no yes Fistula no yes Invasion-organs T1-2 T3-4 Endosono-wall no yes Haema-metas no yes Metas-liver no yes CT-liver no yes Lapa-liver no yes CT-truncus early late Stage no yes Metas-truncus Endosono-truncus no yes no yes Lapa-truncus no yes Endosono-loco no yes CT-loco no

2025

Constrained gradient analysis (similar to the "cubegrade" problem posed by Imielinski, et al. [9]) is to extract pairs of similar cell characteristics associated with big changes in measure in a data cube. Cells are considered similar if they are related by roll-up, drill-down, or 1-dimensional mutation operation. Constrained gradient queries are expressive, capable of capturing trends in data and answering "what-if" questions. To facilitate our discussion, we call one cell in a gradient pair probe cell and the other gradient cell. An efficient algorithm is developed, which pushes constraints deep into the computation process, finding all gradient-probe cell pairs in one pass. It explores bi-directional pruning between probe cells and gradient cells, utilizing transformed measures and dimensions. Moreover, it adopts a hyper-tree structure and an H-cubing method to compress data and maximize sharing of computation. Our performance study shows that this algorithm is efficient and scalable. ½ Anti-monotonicity is very useful for pruning. It states that if a cell does not satisfy an (anti-monotonic) significance constraint × , none of 's descendants can do so. For example, the constraint " ÓÙÒØ ½¼" is anti-monotone. Anti-monotonicity-based pruning forms the foundation for most algorithms for computing iceberg cubes.

2025, Studies in Computational Intelligence

The problem of container inspection at ports-of-entry is formulated in several different ways as an optimization problem. Data generated from different analytical methods, xray detectors, gamma-ray detectors and other sensors used for the detection of chemical, biological, radiological, nuclear, explosive, and other illicit agents are often relied upon to make critical decisions with regard to the nature of containers presented for possible inspection and the appropriate response mechanism. Several important questions related to the utilization and coordination of multiple sensors for container inspection are discussed. New and efficient algorithms for finding the best inspection strategy, including the optimal sequencing of sensors and optimal assignment of thresholds for interpreting sensor readings, are described. Models and algorithms that can be used by decision makers, allowing them to minimize expected cost of inspection, minimize inspection errors (both false positives and false negatives), and/or maximize the throughput of containers, are outlined.

2025, IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems

The layer assignment problem for interconnect is the problem of determining which layers should be used for wiring the signal nets. The objective of the layer assignment problem in general is to minimize the number of vias required. Thus, it is also referred to as the via minimization problem. In a via minimization problem, if the topology of the given layout is fixed, the problem is referred to as a constrained via minimization (CVM) problem. On the other hand, if both the topology of the layout and the layer assignment are to be de cided, it is referred to as an unconstrained via minimization (UVM) problem. In this paper, both the CVM and UVM problems are studied. For the CVM problems, efficient algorithms which can be easily mod ified to take extra constraints into consideration are proposed. Exper imental results show that the proposed algorithms for the CVM prob lem are time efficient compared with existing algorithms and generate better (near-optimal) results. For the UVM problems, a new heuristic approach is presented which generates better results but takes longer computing time. In the CVM problem, some vias are "essential" to the given layout. That is, they have to be selected and cannot be re placed by other possible vias. An efficient algorithm for identifying es sential vias is also presented and discussed in this paper.

2025, arXiv (Cornell University)

This addendum to [O'R17] establishes that a nearly flat acutely triangulated convex cap in the sense of that paper can be edge-unfolded even if closed to a polyhedron by adding the convex polygonal base under the cap.