Acta Cybernetica publishes only original papers in the field of Computer Science. Manuscripts must be written in good English.

Acta Cybernetica publishes only original papers in the field of Computer Science. Manuscripts must be written in clear and proper English.

《Acta Cybernetica》仅发表计算机科学领域的原创论文。稿件必须用良好的英语撰写。

Acta Cybernetica

The unary operators play an important role in continuous-valued logic and in artificial intelligence as well. Based on our previous results concerning these operators, we prove here that (a) the Pliant negation operator (also known as the Dombi form of negation); (b) the substantiating, weakening, modal and linguistic hedge operators; (c) the sharpness operator; and (d) the preference operator can all be written in a common form, which is called the kappa function. The kappa function is an operator class-dependent, universal operator. Here, a sufficient condition for the identity of two kappa functions is presented. Also, we provide the condition for which the conjunctive and disjunctive forms of the kappa function coincide. Next, we demonstrate that the inverse of a kappa function is a kappa function as well. Then, we show that for certain conditions, a set of kappa functions is closed under the composition and conjunctive (or disjunctive) operations. Also, we briefly describe two special cases of the kappa function: the product and the Dombi operator case; and we point out that its extended versions can be applied in various areas.

József Dombi

Tamás Jónás

On a Class of Unary Operators in Continuous-Valued Logic

关于连续值逻辑中的一类一元算子的研究

A crucial problem in combinatorial optimization is the submodular function maximization (SFM), and in many cases it involves graphs on which the maximization is specified. The problem is well-studied and hence there are several proposed algorithms in the literature. The greedy strategy quickly finds a feasible solution that guarantees an approximation of (1-1/e). However, there are many applications that expect an optimal result within a reasonable computational time. One popular method for finding the global optimum is the constraint generation (CG) algorithm. Traditionally, the initial feasible solution of CG is given by the greedy algorithm. It turns out that choosing different starting point than the greedy solution might lead to better performance in terms of running time. In this paper we introduce such a strategy which is beneficial on non-complete bipartite graphs. Benchmarking results on different versions of the solution methods are shown to demonstrate the efficiency of the proposed methods.

Eszter Csókás

Tamás Vinkó

On the Initial Set of Constraints for Graph-Based Submodular Function Maximization

基于图的子模函数最大化初始约束集研究

Let T be a rooted directed tree on n vertices, rooted at v. The rooted subtree frequency vector (RSTF-vector) of T with root v, denoted by rstf(T, v) is a vector of length n whose entry at position k is the number of subtrees of T that contain v and have exactly k vertices. In this paper we present an algorithm for reconstructing rooted directed trees from their rooted subtree frequencies (up to isomorphism). We show that there are examples of nonisomorphic pairs of rooted directed trees that are RSTF-equivalent, s.t. they share the same rooted subtree frequency vectors. We have found all such pairs (groups) for small sizes by using exhaustive computer search. We show that infinitely many nonisomorphic RSTF-equivalent pairs of trees exist by constructing infinite families of examples.

Dénes Bartha

Reconstruction of Rooted Directed Trees

有根有向树的重构

When implementing a non-continuous controller for a cyber-physical system, it may happen that the evolution function of the closed-loop system is not anymore piecewise continuous along the trajectory, mainly due to if statements inside the control algorithm. As a consequence, an unwanted chattering effect may occur. This behavior is often difficult to observe even in simulation. We propose here a set-membership method based on interval analysis to detect different types of discontinuities. One of them is the sliding surface where the state trajectory jumps indefinitely between two distinct behaviors. As an application, we consider the validation of a sailboat controller. We show that our approach is able to detect and explain some unwanted sliding effects that may be observed in rare and specific situations on our actual sailboat robots.

Luc Jaulin

Fabrice Le Bars

Characterizing Sliding Surfaces of Cyber-Physical Systems

表征网络物理系统的滑动面

To model vibrations in flexible structures, a generalized variational formulation of PDE control problems is considered in the frame of the method of integro-differential relations. This approach allows us to estimate a posteriori the quality of finite-dimensional approximations and, as a result, either to refine or coarsen them if necessary. Such estimates also make it possible to correct the related control signals. The procedures for solving optimization problems in dynamics of linear elasticity have been proposed based on the Ritz method and FEM. An original FEM solver for mechanical systems withvarying distributed parameters is described. The resulting control law is regularized via a quadratic cost functional including the discrepancy of the constitutive equations. The verification of optimized control for elastic rod motion involves local and integral error estimates proposed.

Georgy Kostin

Verified Solution to Optimal Control Problems of Elastic Rod Motion Based on the Ritz Method

基于Ritz方法的弹性杆运动最优控制问题的验证解

E-tutoring Systems are computer applications that provide direct customized education to learners. The E-tutoring system usually includes four modules: Teaching Module, Knowledge Module, Learner Module, and Learner Interface. This investigation focuses on Knowledge Module, considering design and implementation for a selected domain. One of the useful mechanisms of Artificial Intelligence (AI) that is commonly used to formalize domain knowledge module concepts and their relation in an E-tutoring systems is ontology. The term ontology is described as a representation of the entities in a domain and the way those entities connect to each other. This paper introduces a domain knowledge module for an E-tutoring system that allows knowledge stored in a well-defined form to support reusability, shareability, flexibility, and standardability and to assist the storage of transfer and prerequisite knowledge relationships. The introduced knowledge domain module is designed in two ways the general concepts domain knowledge module and a specific domain knowledge module ontology. This innovative technique is helpful for students in enhancing their learning progress. Combining the proposed ontology domain knowledge module with an E-tutoring system can enhance the quality of intelligent problem-solving. Also, it will be possible to reuse the knowledge domains. As a result, the proposal of the domain knowledge module for the E-tutoring system can enhance the teaching and learning process, support recommendations, and generate hints. In the future, the suggested module can be improved by adding some functionalities and automatically supporting the generation of problems and their solutions.

Hussein Ali Ahmed Ghanim

László Kovács

Ontology Supported Domain Knowledge Module for E-Tutoring System

本体支持的电子辅导系统领域知识模块

Computer software is driving our everyday life, therefore their security is pivotal. Unfortunately, security flaws are common in software systems, which can result in a variety of serious repercussions, including data loss, secret information disclosure, manipulation, or system failure. Although techniques for detecting vulnerable code exist, the improvement of their accuracy and effectiveness to a practically applicable level remains a challenge. Many existing methods require a substantial amount of human expert labor to develop attributes that indicate vulnerabilities. In previous work, we have shown that machine learning is suitable for solving the issue automatically by learning features from a vast collection of real-world code and predicting vulnerable code locations. Applying a BERT-based code embedding, LSTM models with the best hyperparameters were able to identify seven different security flaws in Python source code with high precision (average of 91%) and recall (average of 83%). Upon the encouraging first empirical results, we go beyond this paper and discuss the challenges of applying these models in practice and outlining a method that solves these issues. Our goal is to develop a hands-on tool for developers that they can use to pinpoint potentially vulnerable spots in their code.

Amirreza Bagheri

Péter Hegedűs

Towards a Block-Level ML-Based Python Vulnerability Detection Tool

面向块级基于机器学习的Python漏洞检测工具

It is not always clear in case of a software project who has the right amount of knowledge concerning a certain module or file. Programmers frequently ask questions like "Who knows the most about this code?" or "Who can I ask for help when I work on this module?". In a large, long-term software product, knowledge is distributed in an uneven way among developers. Developer fluctuation during the product lifetime might cause some parts of the code to be known very well by a multitude of developers, while other parts might sink to the "gray zone", where developer competence is dangerously scarce. It is important for the project management to identify such critical points, to avoid the complete loss of competence. Version control repositories contain loads of useful information about the evolution of a software project. This paper presents a developer-centered visualization that is intended to show individual, team-bound and company-bound knowledge of large legacy projects. The competence information is computed from the extracted version control information from Git repositories. The calculated competence value is based on the number of commits per developer and their significance. Aggregated views for teams and companies are available based on various heuristics. The visualization is implemented as a new plugin in CodeCompass, a standalone, open-source code comprehension software. Project managers and individual developers may both profit from the tool, whether it concerns software evolution, human-resource management, architecture, knowledge catch-up, or blame.

短名	Acta Cybern.
Journal Impact	0.50
国际分区	COMPUTER SCIENCE, CYBERNETICS(Q4)

ISSN	0324-721X, 2676-993X
h-index	18

涉及主题	计算机科学数学程序设计语言人工智能哲学物理算法工程类理论计算机科学组合数学语言学操作系统离散数学数学分析生物
出版信息	出版商: University of Szeged, Institute of Informatics，出版周期: ，期刊类型: journal，开源期刊: 否
基本数据	创刊年份: 1990，原创研究文献占比: 100.00%，自引率:0.00%， Gold OA占比: 98.08%

Acta Cybernetica

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投稿经验分享

On a Class of Unary Operators in Continuous-Valued Logic

On the Initial Set of Constraints for Graph-Based Submodular Function Maximization

Reconstruction of Rooted Directed Trees

Characterizing Sliding Surfaces of Cyber-Physical Systems

Verified Solution to Optimal Control Problems of Elastic Rod Motion Based on the Ritz Method

On the Initial Set of Constraints for Graph-Based Submodular Function Maximization

On a Class of Unary Operators in Continuous-Valued Logic

Ontology Supported Domain Knowledge Module for E-Tutoring System

Towards a Block-Level ML-Based Python Vulnerability Detection Tool

Using Version Control Information to Visualize Developers' Knowledge