Journal of Computer and System Sciences最新文献_第2页

Parameterized analysis of the cops and robber problem 警匪问题的参数化分析

IF 0.9 3区计算机科学 Q1 BUSINESS, FINANCE

Journal of Computer and System Sciences

Pub Date : 2026-06-01 Epub Date: 2026-02-04 DOI: 10.1016/j.jcss.2026.103781

Harmender Gahlawat , Meirav Zehavi

Pursuit-evasion games have been intensively studied for several decades due to their numerous applications in artificial intelligence, robot motion planning, database theory, distributed computing, and algorithmic theory. Cops and Robber (CnR) is one of the most well-known pursuit-evasion games played on graphs, where multiple cops pursue a single robber. The aim is to compute the cop number of a graph, k, which is the minimum number of cops that ensures the capture of the robber. From the viewpoint of parameterized complexity, CnR is W[2]-hard parameterized by k (Fomin et al. (2010) [39]). Thus, we study structural parameters of the input graph. We begin with the vertex cover number (

vcn

). First, we establish that

k \leq \frac{vcn}{3} + 1

. Second, we prove that CnR parameterized by

vcn

is

FPT

by designing an exponential kernel. We complement this result by showing that it is unlikely for CnR parameterized by

vcn

to admit a polynomial compression. We extend our exponential kernels to the parameters cluster vertex deletion number and deletion to stars number, and design a linear vertex kernel for neighborhood diversity. Additionally, we extend all of our results to several well-studied variations of CnR.

由于追逃博弈在人工智能、机器人运动规划、数据库理论、分布式计算和算法理论等领域的广泛应用，几十年来人们对其进行了深入的研究。《Cops and robbers》（简称CnR）是最著名的图形游戏之一，游戏中多个警察追捕一个抢劫犯。其目的是计算图k的警察数量，k是确保捕获抢劫犯的最小警察数量。从参数化复杂度的角度来看，CnR为W[2]-硬参数化k （Fomin et al.(2010)[39]）。因此，我们研究了输入图的结构参数。我们从顶点覆盖数（vcn）开始。首先，我们建立k≤vcn3+1。其次，我们通过设计一个指数核来证明vcn参数化的CnR是FPT。我们通过证明由vcn参数化的CnR不太可能允许多项式压缩来补充这个结果。我们将指数核扩展到聚类顶点删除数和星数删除数参数，并设计了一个线性顶点核用于邻域多样性。此外，我们将所有结果扩展到CnR的几个充分研究的变化。

{"title":"Parameterized analysis of the cops and robber problem","authors":"Harmender Gahlawat , Meirav Zehavi","doi":"10.1016/j.jcss.2026.103781","DOIUrl":"10.1016/j.jcss.2026.103781","url":null,"abstract":"<div><div>Pursuit-evasion games have been intensively studied for several decades due to their numerous applications in artificial intelligence, robot motion planning, database theory, distributed computing, and algorithmic theory. Cops and Robber (CnR) is one of the most well-known pursuit-evasion games played on graphs, where multiple cops pursue a single robber. The aim is to compute the cop number of a graph, k, which is the minimum number of cops that ensures the capture of the robber. From the viewpoint of parameterized complexity, CnR is W[2]-hard parameterized by k (Fomin et al. (2010) [39]). Thus, we study structural parameters of the input graph. We begin with the vertex cover number (<math><mi>vcn</mi></math>). First, we establish that <math><mi>k</mi><mo>≤</mo><mfrac><mrow><mi>vcn</mi></mrow><mrow><mn>3</mn></mrow></mfrac><mo>+</mo><mn>1</mn></math>. Second, we prove that CnR parameterized by <math><mi>vcn</mi></math> is <math><mi>FPT</mi></math> by designing an exponential kernel. We complement this result by showing that it is unlikely for CnR parameterized by <math><mi>vcn</mi></math> to admit a polynomial compression. We extend our exponential kernels to the parameters cluster vertex deletion number and deletion to stars number, and design a linear vertex kernel for neighborhood diversity. Additionally, we extend all of our results to several well-studied variations of CnR.</div></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"158 ","pages":"Article 103781"},"PeriodicalIF":0.9,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146190213","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Kernelization for orthogonality dimension 正交维数的核化

IF 0.9 3区计算机科学 Q1 BUSINESS, FINANCE

Journal of Computer and System Sciences

Pub Date : 2026-05-01 Epub Date: 2026-01-08 DOI: 10.1016/j.jcss.2026.103757

Ishay Haviv, Dror Rabinovich

The orthogonality dimension of a graph over

R

is the smallest integer d for which one can assign to every vertex a nonzero vector in

R^{d}

such that every two adjacent vertices receive orthogonal vectors. For an integer d, the

problem asks to decide whether the orthogonality dimension of a given graph over

R

is at most d. We prove that for every integer

d \geq 3

, the

problem parameterized by the vertex cover number k admits a kernel with

O (k^{d - 1})

vertices and bit-size

O (k^{d - 1} \cdot \log k)

. We complement this result by a nearly matching lower bound, showing that for any

ε > 0

, the problem admits no kernel of bit-size

O (k^{d - 1 - ε})

unless

NP \subseteq coNP / poly

. We further study the kernelizability of orthogonality dimension problems in additional settings, including over general fields and under various structural parameterizations.

R上的图的正交维数是最小的整数d，可以为每个顶点分配一个Rd中的非零向量，使得每个相邻的两个顶点都得到正交向量。对于整数d，该问题要求确定给定图在R上的正交维数是否最大为d。我们证明了对于每一个整数d≥3，用顶点覆盖数k参数化的问题承认一个具有O（kd−1）个顶点和O（kd−1⋅log (k)）位大小的核。我们用一个几乎匹配的下界来补充这一结果，表明对于任意ε>；0，问题不存在位大小为0 （kd−1−ε）的核，除非NP≠coNP/poly。我们进一步研究了正交维问题在其他情况下的可核化性，包括在一般域上和在各种结构参数化下。

{"title":"Kernelization for orthogonality dimension","authors":"Ishay Haviv, Dror Rabinovich","doi":"10.1016/j.jcss.2026.103757","DOIUrl":"10.1016/j.jcss.2026.103757","url":null,"abstract":"<div><div>The orthogonality dimension of a graph over <math><mi>R</mi></math> is the smallest integer d for which one can assign to every vertex a nonzero vector in <math><msup><mrow><mi>R</mi></mrow><mrow><mi>d</mi></mrow></msup></math> such that every two adjacent vertices receive orthogonal vectors. For an integer d, the <figure><img></figure> problem asks to decide whether the orthogonality dimension of a given graph over <math><mi>R</mi></math> is at most d. We prove that for every integer <math><mi>d</mi><mo>≥</mo><mn>3</mn></math>, the <figure><img></figure> problem parameterized by the vertex cover number k admits a kernel with <math><mi>O</mi><mo>(</mo><msup><mrow><mi>k</mi></mrow><mrow><mi>d</mi><mo>−</mo><mn>1</mn></mrow></msup><mo>)</mo></math> vertices and bit-size <math><mi>O</mi><mo>(</mo><msup><mrow><mi>k</mi></mrow><mrow><mi>d</mi><mo>−</mo><mn>1</mn></mrow></msup><mo>⋅</mo><mi>log</mi><mo>⁡</mo><mi>k</mi><mo>)</mo></math>. We complement this result by a nearly matching lower bound, showing that for any <math><mi>ε</mi><mo>></mo><mn>0</mn></math>, the problem admits no kernel of bit-size <math><mi>O</mi><mo>(</mo><msup><mrow><mi>k</mi></mrow><mrow><mi>d</mi><mo>−</mo><mn>1</mn><mo>−</mo><mi>ε</mi></mrow></msup><mo>)</mo></math> unless <math><mrow><mi>NP</mi></mrow><mo>⊆</mo><mrow><mi>coNP</mi><mo>/</mo><mi>poly</mi></mrow></math>. We further study the kernelizability of orthogonality dimension problems in additional settings, including over general fields and under various structural parameterizations.</div></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"157 ","pages":"Article 103757"},"PeriodicalIF":0.9,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145976499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A divide and conquer algorithm for deciding group cellular automata dynamics 决定群体元胞自动机动态的分治算法

IF 0.9 3区计算机科学 Q1 BUSINESS, FINANCE

Journal of Computer and System Sciences

Pub Date : 2026-05-01 Epub Date: 2025-12-09 DOI: 10.1016/j.jcss.2025.103749

Niccolò Castronuovo , Alberto Dennunzio , Luciano Margara

We prove that many dynamical properties of group cellular automata (GCA) can be decided by decomposing them into a set of much simpler GCA, provided those properties are decidable for such simpler GCA. Specifically, we provide a novel algorithmic technique that decomposes the GCA under investigation into a finite number of GCA, some defined on abelian groups, while others, if any, on products of simple non-abelian isomorphic groups. Importantly, the groups resulting from the decomposition depend only on the original group and are therefore completely independent of both the automaton and the considered property. Consequently, they do not inherit any aspect of the complexity of the automaton under investigation. We study the inheritance of the dynamical properties in the original GCA versus the same properties in the GCA obtained through decomposition. The latter turn out to be significantly easier to analyze than in the original GCA. Then, we show that injectivity, surjectivity, and equicontinuity/sensitivity to initial conditions can be decided by testing them in the smaller GCA produced by the decomposition. Moreover, we prove that the topological entropy of a GCA can be computed, provided one knows how to compute it for GCA defined on products of simple non-abelian isomorphic groups – for which we explicitly prove how to compute it in the surjective case – and on abelian groups. Finally, we prove that no strongly transitive, and therefore no positively expansive, GCA defined on non-abelian groups exist.

我们证明了群元胞自动机（GCA）的许多动力学性质可以通过分解成一组更简单的GCA来确定，只要这些性质对于这种更简单的GCA是可确定的。具体来说，我们提供了一种新的算法技术，将所研究的GCA分解为有限数量的GCA，其中一些定义在阿贝尔群上，而另一些（如果有的话）定义在简单非阿贝尔同构群的乘积上。重要的是，分解产生的组仅依赖于原始组，因此完全独立于自动机和考虑的属性。因此，它们不继承所研究的自动机复杂性的任何方面。我们研究了原始GCA中动态特性的继承性与通过分解得到的GCA中相同特性的继承性。后者比原来的GCA更容易分析。然后，我们证明了注入性、满射性和对初始条件的等连续性/灵敏度可以通过在分解产生的较小GCA中测试来确定。此外，我们证明了一个GCA的拓扑熵是可以计算的，只要我们知道如何计算定义在简单非阿贝尔同构群的乘积上的GCA（我们明确地证明了如何在满射情况下计算它）和阿贝尔群上的GCA。最后，我们证明了在非阿贝尔群上不存在强传递因而不存在正可扩张的GCA。

{"title":"A divide and conquer algorithm for deciding group cellular automata dynamics","authors":"Niccolò Castronuovo , Alberto Dennunzio , Luciano Margara","doi":"10.1016/j.jcss.2025.103749","DOIUrl":"10.1016/j.jcss.2025.103749","url":null,"abstract":"<div><div>We prove that many dynamical properties of group cellular automata (GCA) can be decided by decomposing them into a set of much simpler GCA, provided those properties are decidable for such simpler GCA. Specifically, we provide a novel algorithmic technique that decomposes the GCA under investigation into a finite number of GCA, some defined on abelian groups, while others, if any, on products of simple non-abelian isomorphic groups. Importantly, the groups resulting from the decomposition depend only on the original group and are therefore completely independent of both the automaton and the considered property. Consequently, they do not inherit any aspect of the complexity of the automaton under investigation. We study the inheritance of the dynamical properties in the original GCA versus the same properties in the GCA obtained through decomposition. The latter turn out to be significantly easier to analyze than in the original GCA. Then, we show that injectivity, surjectivity, and equicontinuity/sensitivity to initial conditions can be decided by testing them in the smaller GCA produced by the decomposition. Moreover, we prove that the topological entropy of a GCA can be computed, provided one knows how to compute it for GCA defined on products of simple non-abelian isomorphic groups – for which we explicitly prove how to compute it in the surjective case – and on abelian groups. Finally, we prove that no strongly transitive, and therefore no positively expansive, GCA defined on non-abelian groups exist.</div></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"157 ","pages":"Article 103749"},"PeriodicalIF":0.9,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145736654","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Approximation algorithms for two extensions of min-k-union 两种min-k-并扩展的逼近算法

IF 0.9 3区计算机科学 Q1 BUSINESS, FINANCE

Journal of Computer and System Sciences

Pub Date : 2026-05-01 Epub Date: 2025-12-16 DOI: 10.1016/j.jcss.2025.103750

Hua Chen , Lin Chen , Shenghao Ye , Guochuan Zhang

In the min-k-union problem (MkU), given a ground set N, a collection

S

of m subsets of N, and an integer k, one needs to select k sets from

S

so that their union has the smallest size. In this paper, we study two extensions of MkU.

The first is the maximum coverage interdiction problem, where there is a leader with cardinality

k_{l}

and a follower with cardinality

k_{f}

. The leader's goal (as well as the problem) is to remove up to

k_{l}

sets from

S

so that the union size of the at most

k_{f}

sets selected by the follower from the remaining sets attains the minimum. We provide an

\tilde{O} (\sqrt{m})

-approximation algorithm, while a lower bound of

Ω (m^{1 / 4})

under the “Dense versus Random” conjecture for MkU [Chlamtáč et al. '17] applies to our problem as well. When

k_{l} = m - k_{f}

, this problem becomes MkU.

The second problem deals with monotone submodular minimization with a cardinality constraint. Given a ground set N of n elements, a nonnegative monotone submodular function f, and an integer k, we are required to find a size-k set

S \subseteq N

that minimizes

f (S)

. We propose a 2

\sqrt{n}

-approximation algorithm, matching (up to a logarithmic factor) the lower bound of

Ω (\sqrt{\frac{n}{\ln n}})

[Svitkina and Fleischer '11]. When f is a coverage function, this problem becomes MkU.

在min-k-并问题（MkU）中，给定一个基集N，一个由N的m个子集组成的集合S，以及一个整数k，需要从S中选择k个集合，使它们的并集具有最小的大小。本文研究了MkU的两个扩展。第一个是最大覆盖拦截问题，其中有一个基数为kl的领导者和一个基数为kf的追随者。领导者的目标（和问题一样）是从S中移除最多kl个集合，使追随者从剩余集合中选择的最多kf个集合的并集大小达到最小。我们提供了一个O ~ (m)-近似算法，而MkU在“密集与随机”猜想下的下界Ω（m1/4） [Chlamtáč等人]。[17]也适用于我们的问题。当kl=m−kf时，这个问题变成了MkU。第二个问题处理带有基数约束的单调次模最小化问题。给定一个有N个元素的基集N、一个非负单调子模函数f和一个整数k，求一个大小为k的集S≥f(S)。我们提出了一个2n近似算法，匹配（直到一个对数因子）Ω（nln ln n）的下界[Svitkina和Fleischer '11]。当f是一个覆盖函数时，这个问题就变成了MkU。

{"title":"Approximation algorithms for two extensions of min-k-union","authors":"Hua Chen , Lin Chen , Shenghao Ye , Guochuan Zhang","doi":"10.1016/j.jcss.2025.103750","DOIUrl":"10.1016/j.jcss.2025.103750","url":null,"abstract":"<div><div>In the min-k-union problem (MkU), given a ground set N, a collection <math><mi>S</mi></math> of m subsets of N, and an integer k, one needs to select k sets from <math><mi>S</mi></math> so that their union has the smallest size. In this paper, we study two extensions of MkU.</div><div>The first is the maximum coverage interdiction problem, where there is a leader with cardinality <math><msub><mrow><mi>k</mi></mrow><mrow><mi>l</mi></mrow></msub></math> and a follower with cardinality <math><msub><mrow><mi>k</mi></mrow><mrow><mi>f</mi></mrow></msub></math>. The leader's goal (as well as the problem) is to remove up to <math><msub><mrow><mi>k</mi></mrow><mrow><mi>l</mi></mrow></msub></math> sets from <math><mi>S</mi></math> so that the union size of the at most <math><msub><mrow><mi>k</mi></mrow><mrow><mi>f</mi></mrow></msub></math> sets selected by the follower from the remaining sets attains the minimum. We provide an <math><mover><mrow><mi>O</mi></mrow><mrow><mo>˜</mo></mrow></mover><mo>(</mo><msqrt><mrow><mi>m</mi></mrow></msqrt><mo>)</mo></math>-approximation algorithm, while a lower bound of <math><mi>Ω</mi><mo>(</mo><msup><mrow><mi>m</mi></mrow><mrow><mn>1</mn><mo>/</mo><mn>4</mn></mrow></msup><mo>)</mo></math> under the “Dense versus Random” conjecture for MkU [Chlamtáč et al. '17] applies to our problem as well. When <math><msub><mrow><mi>k</mi></mrow><mrow><mi>l</mi></mrow></msub><mo>=</mo><mi>m</mi><mo>−</mo><msub><mrow><mi>k</mi></mrow><mrow><mi>f</mi></mrow></msub></math>, this problem becomes MkU.</div><div>The second problem deals with monotone submodular minimization with a cardinality constraint. Given a ground set N of n elements, a nonnegative monotone submodular function f, and an integer k, we are required to find a size-k set <math><mi>S</mi><mo>⊆</mo><mi>N</mi></math> that minimizes <math><mi>f</mi><mo>(</mo><mi>S</mi><mo>)</mo></math>. We propose a 2<math><msqrt><mrow><mi>n</mi></mrow></msqrt></math>-approximation algorithm, matching (up to a logarithmic factor) the lower bound of <math><mi>Ω</mi><mo>(</mo><msqrt><mrow><mfrac><mrow><mi>n</mi></mrow><mrow><mi>ln</mi><mo>⁡</mo><mi>n</mi></mrow></mfrac></mrow></msqrt><mo>)</mo></math> [Svitkina and Fleischer '11]. When f is a coverage function, this problem becomes MkU.</div></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"157 ","pages":"Article 103750"},"PeriodicalIF":0.9,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145839599","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Morphing graph drawings in the presence of point obstacles 存在点障碍物时的变形图形绘制

IF 0.9 3区计算机科学 Q1 BUSINESS, FINANCE

Journal of Computer and System Sciences

Pub Date : 2026-05-01 Epub Date: 2026-01-07 DOI: 10.1016/j.jcss.2026.103755

Oksana Firman, Tim Hegemann, Boris Klemz, Felix Klesen, Marie Diana Sieper, Alexander Wolff, Johannes Zink

A crossing-free morph is a continuous deformation between two graph drawings that preserves straight-line pairwise noncrossing edges. Motivated by applications in 3D morphing problems, we initiate the study of morphing graph drawings in the plane in the presence of stationary point obstacles, which need to be avoided throughout the deformation. As our main result, we prove that it is NP-hard to decide whether such an obstacle-avoiding 2D morph between two given drawings of the same graph exists. In fact, this statement remains true even in the severely restricted special case where only three vertices have to change positions. This is in sharp contrast to the classical case without obstacles, where there is an efficiently verifiable (necessary and sufficient) criterion for the existence of a morph. Further, we provide several combinatorial results related to conditions under which the existence of a morph between two drawings of a graph can or cannot be prevented by the placement of a given number of point obstacles.

无交叉变形是两个图形之间的连续变形，它保留直线成对的不相交边。受三维变形问题应用的启发，我们开始研究平面上存在静止点障碍物的变形图形绘制，这些障碍物在整个变形过程中都需要避免。作为我们的主要结果，我们证明了在同一图的两个给定图形之间是否存在这样的避障二维变形是np困难的。事实上，即使在只有三个顶点需要改变位置的严格限制的特殊情况下，这个说法仍然成立。这与没有障碍的经典情况形成鲜明对比，在经典情况下，对于变形的存在有一个有效可验证的（必要和充分的）标准。此外，我们提供了几个组合结果，在这些条件下，图形的两个绘图之间的变形存在是否可以通过放置给定数量的点障碍物来阻止。

引用次数: 0

AdapBlinker: Robust adaptive median filter approach to detect subtle eye blinks AdapBlinker：鲁棒自适应中值滤波方法检测细微眨眼

IF 0.9 3区计算机科学 Q1 BUSINESS, FINANCE

Journal of Computer and System Sciences

Pub Date : 2026-05-01 Epub Date: 2025-12-11 DOI: 10.1016/j.jcss.2025.103746

Hafsa Sidaq , Lei Wang , Jiancheng Chi , Hussain Haider

Nowadays, eye blink detection is gaining significant attention in human-computer interaction systems. Users are increasingly favoring interactions with their phones and computers through non-manual methods, underscoring the constraints of conventional touch interfaces. Wearable technology, such as electrooculography (EOG)-based approaches and infrared sensors (IR), can accurately detect eye blinks; nevertheless, they can be inconvenient after prolonged use. Despite this, the drawbacks of camera-based eye blink recognition techniques are blind spots and the lighting effect. Thus, this study proposes an acoustic signal-based eye blink detection system to overcome these constraints. Acoustic signals can perform fine-grained detection within localized range due to their high attenuation in the air medium. The main benefit of acoustic sensing over conventional methods is that it senses signals directly, so the user does not need to wear any sensors. The prevalence of speakers and microphones in devices is another advancement that supports acoustic sensing. In this research, we present AdapBlinker, which employs the HP ProBook 440 G5 laptop to generate acoustic signals, retrieve data, process acquired signals, and plot Fast Fourier transform (FFT) to extract eye blink signals. AdapBlinker uses an adaptive median filter that adapts to surroundings, eliminates intrusions, and detects subtle blinks. We tested AdapBlinker with thirty-four participants across three settings for five months, achieving an average eye blink detection accuracy of 97.2%.

目前，眨眼检测在人机交互系统中受到越来越多的关注。用户越来越喜欢通过非手动方式与手机和电脑进行交互，这凸显了传统触摸界面的局限性。可穿戴技术，如基于眼电图（EOG）的方法和红外传感器（IR），可以准确地检测眨眼；然而，长时间使用可能会带来不便。尽管如此，基于摄像头的眨眼识别技术的缺点是盲点和灯光效果。因此，本研究提出了一种基于声信号的眨眼检测系统来克服这些限制。由于声信号在空气介质中的高衰减，可以在局部范围内进行细粒度检测。与传统方法相比，声传感的主要优点是它直接感知信号，因此用户不需要佩戴任何传感器。扬声器和麦克风在设备中的普及是支持声传感的另一个进步。在这项研究中，我们提出了AdapBlinker，它使用HP ProBook 440 G5笔记本电脑来产生声信号，检索数据，处理采集的信号，并绘制快速傅里叶变换（FFT）来提取眨眼信号。AdapBlinker使用自适应中值滤波器来适应周围环境，消除干扰，并检测细微的眨眼。我们对34名参与者进行了为期5个月的三种设置测试，达到了97.2%的平均眨眼检测准确率。

{"title":"AdapBlinker: Robust adaptive median filter approach to detect subtle eye blinks","authors":"Hafsa Sidaq , Lei Wang , Jiancheng Chi , Hussain Haider","doi":"10.1016/j.jcss.2025.103746","DOIUrl":"10.1016/j.jcss.2025.103746","url":null,"abstract":"<div><div>Nowadays, eye blink detection is gaining significant attention in human-computer interaction systems. Users are increasingly favoring interactions with their phones and computers through non-manual methods, underscoring the constraints of conventional touch interfaces. Wearable technology, such as electrooculography (EOG)-based approaches and infrared sensors (IR), can accurately detect eye blinks; nevertheless, they can be inconvenient after prolonged use. Despite this, the drawbacks of camera-based eye blink recognition techniques are blind spots and the lighting effect. Thus, this study proposes an acoustic signal-based eye blink detection system to overcome these constraints. Acoustic signals can perform fine-grained detection within localized range due to their high attenuation in the air medium. The main benefit of acoustic sensing over conventional methods is that it senses signals directly, so the user does not need to wear any sensors. The prevalence of speakers and microphones in devices is another advancement that supports acoustic sensing. In this research, we present AdapBlinker, which employs the HP ProBook 440 G5 laptop to generate acoustic signals, retrieve data, process acquired signals, and plot Fast Fourier transform (FFT) to extract eye blink signals. AdapBlinker uses an adaptive median filter that adapts to surroundings, eliminates intrusions, and detects subtle blinks. We tested AdapBlinker with thirty-four participants across three settings for five months, achieving an average eye blink detection accuracy of 97.2%.</div></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"157 ","pages":"Article 103746"},"PeriodicalIF":0.9,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145924260","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

On the structure of Hamiltonian graphs with small independence number 小独立数哈密顿图的结构

IF 0.9 3区计算机科学 Q1 BUSINESS, FINANCE

Journal of Computer and System Sciences

Pub Date : 2026-05-01 Epub Date: 2026-01-05 DOI: 10.1016/j.jcss.2025.103754

Nikola Jedličková , Jan Kratochvíl

A Hamiltonian path (cycle) in a graph is a path (cycle, respectively) which passes through all of its vertices exactly once. The problems of deciding the existence of a Hamiltonian path and a Hamiltonian cycle in an input graph (called Hamiltonian Path resp. Hamiltonian Cycle) is well known to be NP-complete, and restricted classes of graphs which allow for their polynomial-time solutions are intensively investigated. Until very recently, the complexity was open even for graphs of independence number at most 3. Fomin, Golovach, Sagunov, and Simonov [arxiv 2024] showed that for every integer k, Hamiltonian Path and Hamiltonian Cycle are polynomial-time solvable in graphs of independence number bounded by k, and moreover, that these problems are in FPT when parameterized by the independence number of the input graph. As a companion structural result to these general algorithms, we determine explicit obstacles to the existence of a Hamiltonian path for small values of k, namely for graphs of independence number 2, 3, and 4. Identifying these obstacles in an input graph yields alternative polynomial-time algorithms for Hamiltonian Path and Hamiltonian Cycle with no large hidden multiplicative constants.

图中的哈密顿路径（循环）是经过所有顶点一次的路径（循环）。确定输入图中哈密顿路径和哈密顿循环是否存在的问题（称为哈密顿路径问题）。哈密顿循环)众所周知是np完全的，并且对允许其多项式时间解的图的限制类进行了深入的研究。直到最近，即使独立数最多为3的图的复杂性也是开放的。Fomin, Golovach, Sagunov， and Simonov [arxiv 2024]证明了对于每一个整数k， hamilton Path和hamilton Cycle在以k为界的独立数的图中都是多项式时间可解的，并且当用输入图的独立数参数化时，这些问题在FPT中。作为这些一般算法的伴随结构结果，我们确定了小k值的哈密顿路径存在的显式障碍，即独立数为2、3和4的图。在输入图中识别这些障碍，可以产生哈密顿路径和哈密顿循环的替代多项式时间算法，没有大的隐藏乘法常数。

{"title":"On the structure of Hamiltonian graphs with small independence number","authors":"Nikola Jedličková , Jan Kratochvíl","doi":"10.1016/j.jcss.2025.103754","DOIUrl":"10.1016/j.jcss.2025.103754","url":null,"abstract":"<div><div>A Hamiltonian path (cycle) in a graph is a path (cycle, respectively) which passes through all of its vertices exactly once. The problems of deciding the existence of a Hamiltonian path and a Hamiltonian cycle in an input graph (called Hamiltonian Path resp. Hamiltonian Cycle) is well known to be NP-complete, and restricted classes of graphs which allow for their polynomial-time solutions are intensively investigated. Until very recently, the complexity was open even for graphs of independence number at most 3. Fomin, Golovach, Sagunov, and Simonov [arxiv 2024] showed that for every integer k, Hamiltonian Path and Hamiltonian Cycle are polynomial-time solvable in graphs of independence number bounded by k, and moreover, that these problems are in FPT when parameterized by the independence number of the input graph. As a companion structural result to these general algorithms, we determine explicit obstacles to the existence of a Hamiltonian path for small values of k, namely for graphs of independence number 2, 3, and 4. Identifying these obstacles in an input graph yields alternative polynomial-time algorithms for Hamiltonian Path and Hamiltonian Cycle with no large hidden multiplicative constants.</div></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"157 ","pages":"Article 103754"},"PeriodicalIF":0.9,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145976510","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

On the structural parameterized complexity of defective coloring 缺陷着色的结构参数化复杂度

IF 0.9 3区计算机科学 Q1 BUSINESS, FINANCE

Journal of Computer and System Sciences

Pub Date : 2026-05-01 Epub Date: 2025-11-11 DOI: 10.1016/j.jcss.2025.103736

Sriram Bhyravarapu , Pankaj Kumar , Saket Saurabh

In this paper, we consider the problem Defective Coloring. Given a graph G and two positive integers k and

Δ^{⁎}

, the objective is to determine whether it is possible to obtain a coloring (not necessarily proper) of the vertices of G using at most k colors such that each vertex has at most

Δ^{⁎}

neighbors in the same color class. Defective Coloring is a generalization of Graph Coloring with

Δ^{⁎} = 0

. The optimization variant of this problem, which aims to find the minimum number of colors k, is known to be NP-hard even for split graphs and cographs. Belmonte, Lampis, and Mitsou (SIDMA 2020) showed that Defective Coloring is W[1]-hard when parameterized by feedback vertex set or by treedepth, which implies W[1]-hardness for path-width and treewidth parameters. The problem is W[1]-hard parameterized by modular-width or clique-width as Defective Coloring is NP-hard on cographs. They asked whether Defective Coloring is fixed-parameter tractable (FPT) when parameterized by modular-width, neighborhood diversity or clique-width combined with either k or

Δ^{⁎}

. In an effort to address the question concerning modular-width, this study investigates the parameters neighborhood diversity and twin-cover, which are special cases of modular-width. We show that Defective Coloring is FPT when parameterized by twin-cover, distance to disjoint paths, or the combined parameters neighborhood diversity and k. The latter implies an FPT algorithm for complete-d-partite graphs, a subclass of cographs, parameterized by d. We present an algorithm for graphs with bounded distance to d-degree. We also present a 1-additive approximation algorithm for split graphs.

本文考虑了缺陷着色问题。给定一个图G和两个正整数k和Δ ，目标是确定是否有可能使用最多k种颜色获得G的顶点的着色（不一定是适当的），使得每个顶点在同一颜色类中最多有Δ 邻居。缺陷着色是Δ =0的图着色的一种推广。这个问题的优化变体，旨在找到最小颜色k的数量，已知即使对于分割图和图也是np困难的。Belmonte, Lampis, and Mitsou （SIDMA 2020）表明，当用反馈顶点集或树深度参数化时，缺陷着色是W[1]-硬度，这意味着路径宽度和树宽度参数的硬度为W[1]-硬度。由于缺陷着色在图上是NP-hard的，所以问题是用模宽度或团宽度参数化w[1]-hard。他们问，当用模块宽度、邻域多样性或与k或Δ联合的团宽度进行参数化时，缺陷着色是否是固定参数可处理的（FPT）。为了解决模块宽度的问题，本文研究了模块宽度的特殊情况——邻域多样性和双覆盖参数。我们证明了当用双覆盖、到不相交路径的距离或结合参数邻域多样性和k来参数化时，缺陷着色是FPT。后者暗示了一种用于完全d部图的FPT算法，完全d部图是图的一个子类，参数化为d。我们提出了一种用于到d度有界距离的图的算法。我们还提出了一个分割图的1加性近似算法。

{"title":"On the structural parameterized complexity of defective coloring","authors":"Sriram Bhyravarapu , Pankaj Kumar , Saket Saurabh","doi":"10.1016/j.jcss.2025.103736","DOIUrl":"10.1016/j.jcss.2025.103736","url":null,"abstract":"<div><div>In this paper, we consider the problem Defective Coloring. Given a graph G and two positive integers k and <math><msup><mrow><mi>Δ</mi></mrow><mrow><mo>⁎</mo></mrow></msup></math>, the objective is to determine whether it is possible to obtain a coloring (not necessarily proper) of the vertices of G using at most k colors such that each vertex has at most <math><msup><mrow><mi>Δ</mi></mrow><mrow><mo>⁎</mo></mrow></msup></math> neighbors in the same color class. Defective Coloring is a generalization of Graph Coloring with <math><msup><mrow><mi>Δ</mi></mrow><mrow><mo>⁎</mo></mrow></msup><mo>=</mo><mn>0</mn></math>. The optimization variant of this problem, which aims to find the minimum number of colors k, is known to be NP-hard even for split graphs and cographs. Belmonte, Lampis, and Mitsou (SIDMA 2020) showed that Defective Coloring is W[1]-hard when parameterized by feedback vertex set or by treedepth, which implies W[1]-hardness for path-width and treewidth parameters. The problem is W[1]-hard parameterized by modular-width or clique-width as Defective Coloring is NP-hard on cographs. They asked whether Defective Coloring is fixed-parameter tractable (FPT) when parameterized by modular-width, neighborhood diversity or clique-width combined with either k or <math><msup><mrow><mi>Δ</mi></mrow><mrow><mo>⁎</mo></mrow></msup></math>. In an effort to address the question concerning modular-width, this study investigates the parameters neighborhood diversity and twin-cover, which are special cases of modular-width. We show that Defective Coloring is FPT when parameterized by twin-cover, distance to disjoint paths, or the combined parameters neighborhood diversity and k. The latter implies an FPT algorithm for complete-d-partite graphs, a subclass of cographs, parameterized by d. We present an algorithm for graphs with bounded distance to d-degree. We also present a 1-additive approximation algorithm for split graphs.</div></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"157 ","pages":"Article 103736"},"PeriodicalIF":0.9,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145580509","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The power of knowledge in linear search for an escaping target 知识在线性搜索逃跑目标中的力量

IF 0.9 3区计算机科学 Q1 BUSINESS, FINANCE

Journal of Computer and System Sciences

Pub Date : 2026-05-01 Epub Date: 2025-12-08 DOI: 10.1016/j.jcss.2025.103737

Jared Coleman , Dmitry Ivanov , Evangelos Kranakis , Danny Krizanc , Oscar Morales-Ponce

We consider linear search for an escaping target whose speed and/or initial distance from the origin may be unknown to the searcher. The searcher (an autonomous mobile agent) is initially placed at the origin of the real line and can move with maximum speed 1 in either direction along the line. The oblivious mobile target that is moving away from the origin with a constant speed

v < 1

is initially placed by an adversary on the infinite line at distance d from the origin in an unknown direction. We consider four cases, depending on whether v and/or d is known to the searcher. The main contributions of this paper are new lower bounds as well as algorithms leading to new upper bounds for search in these settings. We present tight bounds for the cases when v is known. For the cases where v is unknown, we prove an optimal (up to lower order terms in the exponent) competitive ratio in the case where d is known and improved upper and lower bounds for the case where d is unknown. These results solve an open problem proposed in Coleman et al. (2022) [11].

我们考虑对逃逸目标的线性搜索，该目标的速度和/或到原点的初始距离对于搜索者来说可能是未知的。搜索器（一个自主移动代理）最初被放置在真实线路的原点，可以沿着线路以最大速度向任何方向移动。以恒定速度v<；1远离原点的遗忘移动目标最初被对手放置在距离原点d处的无限大线上，方向未知。我们考虑四种情况，取决于搜索者是否知道v和/或d。本文的主要贡献是新的下界以及在这些设置中导致新的上界搜索的算法。对于已知v的情况，我们给出了严格的边界。对于v未知的情况，我们证明了d已知情况下的最优竞争比（指数中的低阶项），并改进了d未知情况下的上界和下界。这些结果解决了Coleman等人（2022）提出的一个开放性问题。

{"title":"The power of knowledge in linear search for an escaping target","authors":"Jared Coleman , Dmitry Ivanov , Evangelos Kranakis , Danny Krizanc , Oscar Morales-Ponce","doi":"10.1016/j.jcss.2025.103737","DOIUrl":"10.1016/j.jcss.2025.103737","url":null,"abstract":"<div><div>We consider linear search for an escaping target whose speed and/or initial distance from the origin may be unknown to the searcher. The searcher (an autonomous mobile agent) is initially placed at the origin of the real line and can move with maximum speed 1 in either direction along the line. The oblivious mobile target that is moving away from the origin with a constant speed <math><mi>v</mi><mo><</mo><mn>1</mn></math> is initially placed by an adversary on the infinite line at distance d from the origin in an unknown direction. We consider four cases, depending on whether v and/or d is known to the searcher. The main contributions of this paper are new lower bounds as well as algorithms leading to new upper bounds for search in these settings. We present tight bounds for the cases when v is known. For the cases where v is unknown, we prove an optimal (up to lower order terms in the exponent) competitive ratio in the case where d is known and improved upper and lower bounds for the case where d is unknown. These results solve an open problem proposed in Coleman et al. (2022) [11].</div></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"157 ","pages":"Article 103737"},"PeriodicalIF":0.9,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145736652","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A comparative study of the smallest probability intervals for which a binary sequence is random 对二值序列为随机的最小概率区间的比较研究

IF 0.9 3区计算机科学 Q1 BUSINESS, FINANCE

Journal of Computer and System Sciences

Pub Date : 2026-05-01 Epub Date: 2025-11-13 DOI: 10.1016/j.jcss.2025.103734

Floris Persiau, Gert de Cooman, Jasper De Bock

There are many randomness notions. Classically, many of them are about whether a given infinite binary sequence is random for some given probability, meaning that it is random for the i.i.d. process that assigns this probability to the outcome 1. In that case, if a sequence is random according to several randomness notions, then the probability for which it is random is the same for all these notions. Comparing randomness notions then amounts to finding out according to which of them a given sequence is random. This changes dramatically when we consider randomness for probability intervals, because here, a sequence is always random for at least one such interval, so the question is not if, but rather for which intervals, a sequence is random. We show that for many randomness notions thus generalised, every sequence has a smallest interval for which it is (almost) random. We study such smallest intervals and then use them as a way to compare the corresponding randomness notions. We establish conditions under which such smallest intervals coincide, and provide examples where they do not.

随机性概念有很多。经典地，它们中的许多都是关于给定的无限二进制序列对于某个给定的概率是否是随机的，这意味着对于将该概率分配给结果1的i.i.d.过程来说，它是随机的。在这种情况下，如果一个序列根据几个随机性概念是随机的，那么对于所有这些概念，它是随机的概率是相同的。比较随机性概念就等于找出给定序列中哪一个是随机的。当我们考虑概率区间的随机性时，这就发生了巨大的变化，因为在这里，一个序列至少在一个这样的区间内总是随机的，所以问题不是序列是否随机，而是对于哪个区间，序列是随机的。我们证明了对于许多这样推广的随机性概念，每个序列都有一个（几乎）随机的最小区间。我们研究这样的最小区间，然后用它们来比较相应的随机性概念。我们建立了这些最小间隔重合的条件，并提供了它们不重合的例子。

{"title":"A comparative study of the smallest probability intervals for which a binary sequence is random","authors":"Floris Persiau, Gert de Cooman, Jasper De Bock","doi":"10.1016/j.jcss.2025.103734","DOIUrl":"10.1016/j.jcss.2025.103734","url":null,"abstract":"<div><div>There are many randomness notions. Classically, many of them are about whether a given infinite binary sequence is random for some given probability, meaning that it is random for the i.i.d. process that assigns this probability to the outcome 1. In that case, if a sequence is random according to several randomness notions, then the probability for which it is random is the same for all these notions. Comparing randomness notions then amounts to finding out according to which of them a given sequence is random. This changes dramatically when we consider randomness for probability intervals, because here, a sequence is always random for at least one such interval, so the question is not if, but rather for which intervals, a sequence is random. We show that for many randomness notions thus generalised, every sequence has a smallest interval for which it is (almost) random. We study such smallest intervals and then use them as a way to compare the corresponding randomness notions. We establish conditions under which such smallest intervals coincide, and provide examples where they do not.</div></div>","PeriodicalId":50224,"journal":{"name":"Journal of Computer and System Sciences","volume":"157 ","pages":"Article 103734"},"PeriodicalIF":0.9,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145571842","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0