Utilitas Algorithmica (UA)
ISSN: xxxx-xxxx (print)
Utilitas Algorithmica (UA) is a premier, open-access international journal dedicated to advancing algorithmic research and its applications. Launched to drive innovation in computer science, UA publishes high-impact theoretical and experimental papers addressing real-world computational challenges. The journal underscores the vital role of efficient algorithm design in navigating the growing complexity of modern applications. Spanning domains such as parallel computing, computational geometry, artificial intelligence, and data structures, UA is a leading venue for groundbreaking algorithmic studies.
- Research article
- https://doi.org/10.61091/jcmcc127b-479
- Full Text
- Journal of Combinatorial Mathematics and Combinatorial Computing
- Volume 127b
- Pages: 8723-8745
- Published Online: 16/04/2025
The large number of accesses of distributed power supplies changes the distribution network from a passive network to an active network with small and medium-sized power supplies all over the network, which brings important impacts on all aspects of the distribution network, such as planning, operation, and power quality. The study analyzes the types of distributed power nodes and the traditional trend model of distribution network, studies the changes of voltage and network loss after the integration of distributed power sources into the distribution network, and analyzes the impact of different numbers, capacities and access locations of distributed power sources on the reactive power optimization of the distribution network by means of IEEE33 nodes. Analyze the impact of distributed power supply on distribution network. Firstly, the characteristics of distributed power supply are analyzed, distributed photovoltaic and distributed wind power operation models are established, and the influencing factors of the two power supply outputs are analyzed to generalize the distributed power supply output model. The basic principle of weighted least squares state estimation and its algorithmic process are introduced, and on its basis, an equation-containing constrained state estimation model for dealing with zero-injection nodes in the distribution network is introduced, and finally, the feasibility and validity of the proposed constrained state estimation model’s state estimation method for the distribution network are verified through the analysis of an example of the IEEE 33-node system. Combining the sequence quadratic programming method and the idea of trust domain, the trust domain sequence quadratic programming method is proposed, and the use of the effective set method to quickly solve the sub-quadratic programming problem after downsizing is the key that the algorithm in this paper can solve the optimization problem relatively quickly. The optimization results show that distributed power sources participate in active distribution network reactive power optimization and cooperative control to provide a theoretical basis, and the effectiveness of the method is verified through simulation cases.
- Research article
- https://doi.org/10.61091/jcmcc127b-478
- Full Text
- Journal of Combinatorial Mathematics and Combinatorial Computing
- Volume 127b
- Pages: 8701-8721
- Published Online: 16/04/2025
The distribution network system is directly connected to users, and its faults directly affect people’s daily life and economic activities. In order to realize rapid fault location, isolation and self-healing, this paper carries out a new energy distribution system reliability assessment based on sequential Monte Carlo simulation algorithm. Comparing the use of sequential simulation algorithms, non-sequential simulation algorithms and pseudo-sequential simulation algorithms in the state analysis of distribution network systems, the sequential Monte Carlo method is selected to establish a simulation model for distribution network reliability assessment. According to the “2-3-6” architecture system commonly used in distribution networks, a new energy distribution network self-healing system data communication scheme is designed. The Monte Carlo simulation method is used to model and analyze the reliability of new energy coupled components and to evaluate the reliability indexes. The simulation environment is designed and the RTDS model is used to test the self-healing system of intelligent devices in the distribution network. In the new energy distribution network data scheme designed in this paper, the distribution network self-healing technology is able to remove the fault time within 95ms and complete the fault point elimination work. And when the DG can make the far power side and the switch is located in the near power side, the distribution self-healing system is able to remove the fault point within 60ms time and complete the self-healing operation of the distribution network fault.
- Research article
- https://doi.org/10.61091/jcmcc127b-477
- Full Text
- Journal of Combinatorial Mathematics and Combinatorial Computing
- Volume 127b
- Pages: 8683-8700
- Published Online: 16/04/2025
With the prosperous development of the Internet, the open network environment has also become a breeding ground for hackers, especially in the huge network system, the multi-stage, large-scale and coordinated network attacks have brought great trouble to the traditional defense means. This study designs a network security expert system based on multi-source heterogeneous data based on the characteristics of huge volume of multi-source heterogeneous network security data, heterogeneous format, and diverse semantics. The system contains five hierarchical structures: perception layer, event layer, alarm layer, attack context and attack pattern layer, and attack scenario layer. Petri nets are used for network security risk analysis and assessment to overcome the shortcomings of traditional defenses that become difficult to handle after modeling the attack scenarios. Incorporating the D-S evidence theory, the outputs of multiple decision engines are applied to the network security posture assessment to analyze the network condition from a global perspective and further enhance the effect of network attack classification. In the simulation experiments of simulated attacks, the monitoring information of the network security expert system has autocorrelation coefficients within two times standard deviation ( \(\pm\)0.1) after the 0th-order differencing, which indicates that the system is able to accurately assess the potential values of network attacks, such as scanning, brute-force cracking, DoS, and Web.
- Research article
- https://doi.org/10.61091/jcmcc127b-476
- Full Text
- Journal of Combinatorial Mathematics and Combinatorial Computing
- Volume 127b
- Pages: 8671-8681
- Published Online: 16/04/2025
In the realm of supercapacitor energy storage, multi-element transition metal-oxides with high theoretical specific-capacitance values have been extensively explored. However, their poor electrical conductivity and cycling stability limit their applications. In this study, \(CoMoO_4\)@\(Co_3O_4\)/NF was formed by loading \(Co_3O_4\) on the nickel foam (NF) surface as a substrate by solvent co-precipitation method and annealing treatment first, and then growing \(CoMoO_4\) on the surface of \(Co_3O_4\) by hydrothermal reaction and calcination. \(Co_3O_4\) nanosheets, which are derived from ZIF-67, offer more active sites and simpler ion/electron transport paths. The electrochemical characteristics of the composite electrode can be substantially boosted by the synergistic effect between \(Co_3O_4\) as the inner layer and \(CoMoO_4\) as the outer layer in the \(CoMoO_4\)@\(Co_3O_4\)/nickel foam hierarchical composite structural materials. When combined with activated carbon (AC) to form an asymmetric supercapacitor, it exhibits a capacitance normalized to unit area of 0.669 F \(cm^2\) at 1 mA \(cm^2\). Furthermore, the assembled asymmetric supercapacitor demonstrates an energy per unit volume of 209.29 mWh \(cm^{-2}\) at the current flux of 0.75 mW \(cm^{-2}\), and upholds 89% of its Initial surface capacitance after 6000 cycles.
- Research article
- https://doi.org/10.61091/jcmcc127b-475
- Full Text
- Journal of Combinatorial Mathematics and Combinatorial Computing
- Volume 127b
- Pages: 8661-8670
- Published Online: 16/04/2025
In this study, a complete two-dimensional anatomical model of the rabbit heart was constructed by Zhang et al. The positive effects of external noise stimulation on cardiac pacemaking and conduction have been studied using computer simulations. Our results show that: 1) the slower pacemaking rate or even oscillation cessation, which is induced by the removal of \(i_{Na}\) from the sinoatrial node or a decrease in the active sinoatrial node cell population, can be recovered by adding external noise. 2) Compared to the effect of \(i_{Na}\) removal alone, the combined effect of \(i_{Na}\) and cell death had a greater impact on slowing down the pacemaking rate. These phenomena indicate that external stimuli play an important role in controlling the initiation and conduction of sinoatrial node pacemaker activity, and that the aging heart may experience obstruction of sinus node conduction and even sudden cardiac death due to decreased cell membrane \(i_{Na}\) or partial myocardial cell death. Our results provide insights into the intrinsic mechanisms underlying electroshock healing in some heart diseases.
- Research article
- https://doi.org/10.61091/jcmcc127b-474
- Full Text
- Journal of Combinatorial Mathematics and Combinatorial Computing
- Volume 127b
- Pages: 8639-8660
- Published Online: 16/04/2025
Due to its advantages in energy conservation, emission reduction and recyclability, air-supported membrane structure (ASMS) has been widely implemented in various applications, including large stadiums, conference centers, warehouses and temporary buildings. Compared to traditional building, the structural and material properties of ASMS are special which significantly affect smoke diffusion and flow behavior during fire scenarios. Moreover, the design methods for smoke management system of ASMS buildings are still lacked and further research is required. In this study, a numerical model of a coal storage bin was built. The impact of several key design parameters, including such as height of natural smoke vent, fire source location and makeup air methods, on the performance of ASMS building`s smoke management system were evaluated. Gas temperature, CO concentration, visibility, smoke exhausting quantity, critical pyrolysis temperature and critical heat radiation intensity were selected as evaluation indexes. The results indicated that better natural smoke exhaust efficiency was achieved when the natural smoke vents were located at the height between 80% and 100% of the building’s total height. Setting natural makeup air vent in the wall of smoke bay 3 can achieve the best cooling effect. However, compared to natural makeup air, the natural smoke exhaust efficiency of mechanical makeup air was much better. When the rate of mechanical makeup air reached 120% of the required natural smoke exhausting quantity, it has significant improvements in temperature reduction, visibility and natural smoke exhausting quantity which are crucial for ensuring safe evacuation during fire events. These findings provide a design refer for enhancing fire protection and construction practices in ASMS buildings.
- Research article
- https://doi.org/10.61091/jcmcc127b-473
- Full Text
- Journal of Combinatorial Mathematics and Combinatorial Computing
- Volume 127b
- Pages: 8627-8638
- Published Online: 16/04/2025
The development of modern economy encourages the development of enterprises. As an economic accounting system, the financial integration system is not only an indicator to evaluate the income of enterprises, but also an indicator to evaluate the business status of enterprises. In the modern information environment, how to carry out the financial fusion system information of modern information environment is the focus of enterprises. The information contained in the financial integration system provides complete accounting information for the application of communication network and computer technology by combining modern technical means, and effectively analyze accounting and make reasonable economic plans. In the process of dynamic design of financial integration system, it can avoid accounting risks and significantly improve the economic benefits of the company. Firstly, the paper expounded the analysis of the influencing factors of mobile Internet on accounting information system, and briefly analyzed the relevant factors of financial integration construction. It considered the significance of financial integration construction and proposed effective ways to solve problems. After that, the dynamic planning algorithm was introduced into the financial integration construction design. Finally, the investigation and calculation were carried out. The new accounting information system designed by using dynamic programming algorithm and mobile Internet technology could improve the security and efficiency of enterprises by 38.6%.
- Research article
- https://doi.org/10.61091/jcmcc127b-472
- Full Text
The expansion of information-based education and the growing need for computer laboratories have made their day-to-day management a key part of teaching and learning management activities. The traditional manual management method is inefficient and difficult to handle the increasingly complex management tasks. The emergence of optimized management systems has effectively improved the effectiveness and quality of computer laboratory management work, but the operational efficiency and security of management systems are also facing enormous challenges. To improve the real-time and security of management systems while efficiently completing management tasks, this paper conducted in-depth research on the design of computer laboratory optimization systems using nonlinear engineering algorithms. To verify its effectiveness, this article tested the system from three perspectives: functional implementation, running load, and security performance. The experimental results showed that at the functional implementation level, the average response time of the system for each test case requirement was 1.0767 seconds. It can be seen from the specific results that the demand response speed of the computer laboratory optimization management system based on nonlinear engineering is fast, which can efficiently handle the daily management tasks of the laboratory and promote the improvement of the quality and level of teaching management.
- Research article
- https://doi.org/10.61091/jcmcc127b-471
- Full Text
There are many precious cultural relics collected in the art museum. If it is not properly managed, it will have a great impact on the economy and culture of the country. The construction of a digital art museum that represents the history and culture of the country is very important for the protection, research and dissemination of history and culture. Legacy plays a very important role. Therefore, the current art museum is no longer just a simple display, but more for people to appreciate and understand cultural knowledge, technology and feelings. Under the background and environment of informatization, the main forms of contemporary digital art museums are virtual exhibitions and virtual experiences. From the perspective of art museums, the authenticity of virtual reality is more significant, which can improve the audience’s viewing and experience of various exhibitions. Therefore, under the support of digital technology, the museum combines various exhibits and technologies to present a brand-new “virtual” experience. Based on virtual reality technology, this paper combined digital technology and intelligent technology to establish a virtual display platform for digital art museums with rich content and open sharing. The optimization of the loading mechanism of the scene model can effectively shorten the loading time. When the distance between the viewpoint and the exhibits is within 2m, the optimized shortening time is 509ms. The system can display the virtual art gallery very well. Users can browse the cultural relics exhibits from different perspectives in the scene, so as to realize the real-time roaming of the virtual art gallery scene.
- Research article
- https://doi.org/10.61091/jcmcc127b-470
- Full Text
In response to the problems of traditional visual design that overly relies on designer experience, poor design effectiveness, and low efficiency, this article studied visual design based on digital technology. In this paper, linear stretch visual design image enhancement method and histogram equalization visual design image enhancement method are used to enhance the image of advertising visual design image, packaging visual design image, beauty visual design image, cultural visual design image. Peak signal to noise ratio (PSNR) was used to analyze the effect of digital technology in visual design. The conclusion was drawn that the linear stretching enhanced visual design image method has better results. This article utilized the linear stretching visual design image enhancement method to enhance 20 visual design images, and analyzed the effectiveness of the linear stretching visual design image enhancement method using a questionnaire survey. The survey results indicated that after processing with the linear stretching visual design image enhancement method, the evaluation scores of the enhanced images by the respondents in School S, School T, and School A were 8.28, 8.76, and 8.47, respectively, which were higher than the original image evaluation scores. The visual design method based on digital technology is beneficial for improving the visual effect of images, and is of great significance for the dissemination of visual images.




