Article
Computer Science, Interdisciplinary Applications
Michael Segal, Oren Tzfaty
Summary: The bounded-diameter minimum spanning tree problem seeks to find a minimum weight spanning tree on a connected, weighted, undirected graph G with a diameter no more than D. A new algorithm has been developed that can handle graphs with non-negative weights and has been proven to have a certain performance ratio. The algorithm's performance has been evaluated empirically as well.
COMPUTERS & OPERATIONS RESEARCH
(2022)
Article
Engineering, Electrical & Electronic
Branko Stojanovic, Tomislav Rajic, Darko Sosic
Summary: Climate change, environmental pollution, and the lack of classical energy sources have led many countries to turn to renewable energy. In modern strategies, smart distribution network reconfiguration is applied to minimize power losses and economic costs. Capacitor switching and distribution generation are also incorporated in modern networks. Simulated Annealing and Minimum spanning tree algorithms are used separately to find the best solution for minimizing power losses and costs. Constraints such as hourly reconfiguration and capacitor banks position are considered. Distributed generators, including wind generators and solar panels, are involved in the research. The main contribution is a near optimal solution for a wide time range, realistic network operation/planning forecast, and satisfaction of technical constraints, accompanied by an elaborate economic background.
INTERNATIONAL JOURNAL OF ELECTRICAL POWER & ENERGY SYSTEMS
(2023)
Article
Computer Science, Information Systems
Ali Moradi Amani, Mahdi Jalili
Summary: This manuscript provides a focused overview of modelling power grids as complex networks and their resilience and reliability analysis. The review critically examines vitality metrics in power grid resilience analysis and demonstrates the applicability of these concepts through simulations on benchmark and real power grids.
Article
Computer Science, Interdisciplinary Applications
Alexander V. Smirnov
Summary: This paper mainly studies undirected multiple graphs of any natural multiplicity, including properties of multiple trees and complete spanning trees.
JOURNAL OF COMBINATORIAL OPTIMIZATION
(2022)
Article
Computer Science, Information Systems
Weixing Wang, Angyan Tu, Fredrik Bergholm
Summary: This study proposes a new method for image segmentation based on graph theory and guided feathering. It effectively addresses the challenges posed by intertwined objects and backgrounds, vague boundaries, and similar textures, resulting in improved segmentation accuracy for images with variable targets.
KSII TRANSACTIONS ON INTERNET AND INFORMATION SYSTEMS
(2022)
Article
Neurosciences
Xinyu Liu, Hang Yang, Benjamin Becker, Xiaoqi Huang, Cheng Luo, Chun Meng, Bharat Biswal
Summary: Functional brain networks undergo changes with aging or schizophrenia, and the mechanism of their joint influences remains unclear. The study used a minimal spanning tree algorithm to study brain network critical points and found that schizophrenia patients had a different network structure compared to controls. Structural equation modeling showed that network integration mediated the influence of age on symptom severity in schizophrenia.
HUMAN BRAIN MAPPING
(2021)
Article
Mathematics
Amarja Kathapurkar, Richard Montgomery
Summary: The study proves that for every given alpha value, there exists an appropriate c value and n(0) such that when the size of the graph is greater than or equal to n(0), the directed graph with a minimum semi-degree of at least (1/2 + alpha)n contains a copy of every oriented tree with a maximum degree of at most cn/log n. This result improves previous research and does not use specific regularity lemma.
JOURNAL OF COMBINATORIAL THEORY SERIES B
(2022)
Article
Computer Science, Artificial Intelligence
Yanxi Liu, Bo Lang, Fengnan Quan
Summary: In this paper, we propose a hyperbolic graph convolution model based on the minimum spanning tree, which process the topological structure of the input graph to extract a more hierarchical structure and eliminate noisy edges. By optimizing the consistency of different outputs, it further improves the performance of hyperbolic graph convolution.
APPLIED INTELLIGENCE
(2023)
Article
Mathematics, Interdisciplinary Applications
Wei Wei, Haoyi Li, Qinghui Zhang
Summary: The minimum cut problem and its corresponding algorithms have been extensively studied. A recently proposed acceleration strategy based on tree-cut mapping has shown to be effective but with room for improvement. In this study, we propose using bidirectional pruned tree for tree-cut mapping to efficiently find the min-cut of any node pair in dense and sparse graphs.
CHAOS SOLITONS & FRACTALS
(2023)
Article
Computer Science, Artificial Intelligence
Hao Long, Yinyan Long, Xiao-xia Li, Zhu-ming Long, Fu-ying Wu
Summary: The paper focuses on the strong generalized minimum label spanning tree problem (SGMLSTP) and proposes a community-based zigzag piloting algorithm to improve the high computing costs and lower efficiency of existing algorithms, especially for large graphs. Experimental results demonstrate that our algorithm outperforms state-of-the-art algorithms in terms of effectiveness and performance on typical benchmark datasets.
Article
Mathematics, Applied
Fengming Dong, Jun Ge, Zhangdong Ouyang
Summary: The number of spanning trees in a connected multi-graph can be calculated using the Matrix-Tree Theorem and Tutte's deletion-contraction formula, but this note presents an alternative method based on vertex degrees.
APPLIED MATHEMATICS AND COMPUTATION
(2022)
Article
Management
Penelope Hernandez, Josep E. Peris, Juan Vidal-Puga
Summary: This paper addresses the problem of cost distribution in a minimum cost spanning tree problem. A cooperative game is devised using an optimistic approach and a sequential game is used to define the players' action sets. The main result shows the existence of a unique cost allocation in subgame perfect equilibria, which matches the allocation suggested by the folk rule.
EUROPEAN JOURNAL OF OPERATIONAL RESEARCH
(2023)
Article
Computer Science, Theory & Methods
Takehiro Ito, Yuni Iwamasa, Yasuaki Kobayashi, Yu Nakahata, Yota Otachi, Kunihiro Wasa
Summary: This paper investigates the computational complexity of subgraph reconfiguration problems in directed graphs. The focus is on reconfiguring arborescences in a digraph, where an arborescence is a directed graph that satisfies certain conditions. The paper presents polynomial-time solutions for the problem, as well as PSPACE-complete results for restricted variations. Additionally, a polynomial-time algorithm for finding the shortest reconfiguration sequence between two spanning arborescences is provided.
THEORETICAL COMPUTER SCIENCE
(2023)
Article
Computer Science, Information Systems
Kouei Yamaoka, Taishi Nakashima, Yukoh Wakabayashi, Nobutaka Ono
Summary: This paper presents a novel approach to estimating multiple time delays in sensor arrays that is robust to outliers in the measurements. The proposed method successfully eliminates outliers while ensuring that all time delays can be restored.
Article
Computer Science, Interdisciplinary Applications
Cesar Rego, Frank Mathew
Summary: We develop a scatter search algorithm to solve the classical capacitated minimum spanning tree problem, including both homogeneous and heterogeneous variants. This problem is central in network design applications in industrial engineering, routing and logistics, and communication networks. Since it is an NP-Complete problem, heuristic solution methods are necessary to find high-quality solutions within practical time limits. Our proposed algorithm competes with the best algorithms in the literature and avoids complicated artifacts.
ADVANCES IN ENGINEERING SOFTWARE
(2023)
Article
Engineering, Multidisciplinary
Freddy Cardenas, Jairo Otanez, Juan Inga, Esteban Inga, Andres Ortega
Summary: This paper describes the implementation of D-BLAST spatial multiplexing technique on Software Defined Radio (SDR) equipment. By using USRP Ettus Research x310 devices, the problem of spatial diversity in MIMO Alamouti scheme is addressed and the interference effects due to increase in transmitter antennas are mitigated through nonlinearity of matrix equations and redundancy of information. The experimental results show that the technique achieves gains of around 10dB and 7dB in MIMO 2x2 and MIMO 3x2 scenarios, respectively.
INGENIUS-REVISTA DE CIENCIA Y TECNOLOGIA
(2022)
Article
Green & Sustainable Science & Technology
Pablo Tamay, Esteban Inga
Summary: This article conducts a bibliometric analysis on the design and implementation of charging stations for electric vehicles, proposing a methodological model for design and using software to analyze system behavior and stability. The study shows that the system is stable under various scenarios, with a particular emphasis on protections for three-phase faults.
Article
Chemistry, Analytical
Luis Amaya, Esteban Inga
Summary: This study proposes a method to locate harmonic frequencies that distort the fundamental voltage and current waves in electrical systems using the compressed sensing technique. The compressed sensing algorithm revolutionizes data compression by taking a few random samples and transforming the signal from the time domain to the frequency domain in a compressed form. The reconstructed signal accurately detects the harmonic distortions in the electrical network. The results obtained with compressed sensing are compared with a power quality analyzer, and the analysis shows that compressed sensing performs well in harmonic detection.
Article
Computer Science, Information Systems
Hector Lara, Esteban Inga
Summary: This study introduces a heuristic model for optimizing the route or layout of a subway electrical distribution network, determining the location of transformer substations and reducing material costs by connecting each transformer to a minimum spanning tree. By considering various powers of multi-transformer transformers, the study aims to minimize the number of transformers needed while maintaining efficient power supply. Experimental results showed that the system did not exceed the allowed limit in urban areas of 3.5%.
Article
Multidisciplinary Sciences
Juan Garcia, Esteban Inga
Summary: This paper proposes a georeferenced optimal planning model for deploying an underground network in rural areas to increase electrification. The model uses a heuristic process to minimize the resources required for routing the grid within a specified time horizon. It is scalable based on population density, established and georeferenced zones, and the specified period, adjusting to different variables. The modeling is done in CYME software, considering technical criteria to provide a verifiable planning model. The results consider voltage drop and overload levels in transformers and feeders to deliver optimal power quality to end-users, serving as an alternative to minimize resources in underground deployment for electric distribution companies.
Article
Engineering, Multidisciplinary
M. Campana, P. Masache, E. Inga, D. Carrion
Summary: This article analyzes the negative impact of introducing a type of flexible alternating current transmission system (FACTS) device on voltage stability, reliability, and power supply quality in electrical power systems (EPS). It further examines the impact of a specific FACTS device, Static Synchronous Compensator (STATCOM), on reactive power compensation in the EPS and proposes a methodology to determine its capacity and optimal installation location. The positive effects of installing a Power System Stabilizer (PSS) control for voltage stability in the EPS are also investigated. The article utilizes the IEEE 14-bus base system and applies two mathematical models for power flow calculation in MATLAB software.
INGENIUS-REVISTA DE CIENCIA Y TECNOLOGIA
(2023)
Article
Education & Educational Research
Abdon Ramirez, Esteban Inga
Summary: This research aims to identify teaching-learning mechanisms that promote innovation and educational progress for youth and adult basic education, particularly in rural areas with technological limitations and limited internet access. The study found that using an inverted classroom with no face-to-face interaction and implementing information and communication technology can improve the education level for young people and adults in rural areas.
EDUCATION SCIENCES
(2022)
Article
Energy & Fuels
Wilson Pavon, Esteban Inga, Silvio Simani, Matthew Armstrong
Summary: This research proposes an optimal control approach for a smart grid electrical system with photovoltaic generation, aiming to improve performance by balancing error minimization and operational cost. By incorporating advancements in heuristics and hierarchical control strategies, the proposed control scheme provides an efficient and effective solution for smart grid electrical system control. Implementing this optimal control scheme is expected to bring significant benefits such as reduced impact of renewable energy sources, improved stability, reliability, and efficiency of the power grid, and enhanced overall performance.
Article
Chemistry, Analytical
Esteban Inga, Juan Inga, Roberto Hincapie
Summary: This paper proposes a novel algorithm for assigning paired channels for intelligent metering through wireless connectivity in cellular networks. The algorithm optimizes dynamic channel assignment by exploiting white holes in the cognitive radio spectrum and considering the coexistence of different uplink channels, resulting in improved efficiency and reliability for smart metering.
Article
Green & Sustainable Science & Technology
Paul Garzon, Esteban Inga
Summary: This article discusses how to enhance school assignment research with digital tools by incorporating online and face-to-face interactions and promoting the use and development of information and communication technologies (ICT). The study uses a mixed method approach, including qualitative and quantitative techniques, to analyze related documents. The article explains the conceptual and theoretical framework, methodological criteria, and interdisciplinary approach that align with the profile of the investigated group. The practical application of the proposed methodology demonstrates its effectiveness in achieving a higher level of understanding, competence, and behavior, affirming the importance of education as a foundation for social development, including ICT.
Article
Engineering, Electrical & Electronic
Miguel Campana, Esteban Inga
Summary: The introduction of electric vehicles as an alternative mobility solution requires the deployment of an infrastructure of charging stations. This new concept will help mitigate the environmental impact caused by CO2 emissions from conventional vehicles. The sustainability of the charging station infrastructure depends on meeting the demand for electric vehicle charging and having an adequate number of public and private charging stations distributed in a geolocalized area.
WORLD ELECTRIC VEHICLE JOURNAL
(2023)
Article
Education & Educational Research
Jessica Rivadeneira, Esteban Inga
Summary: This article discusses the applicability of peer instruction (PI) as an interactive teaching method to enhance student participation and motivation in the teaching-learning process. The results indicate that PI has a positive effect in promoting student reflection and discussion, leading to greater satisfaction, motivation, interest, understanding, and participation for both teachers and students.
EDUCATION SCIENCES
(2023)
Article
Energy & Fuels
Miguel Campana, Esteban Inga
Summary: The conventional vehicle fleet worldwide has caused air quality degradation, leading to a shift to electric vehicles (EVs). However, the deployment of electric vehicle charging station infrastructures (EVCSI) is essential for the development of electric mobility. This paper addresses the problem by analyzing heterogeneous vehicular flow, finding solutions to the transportation problem, and determining the optimal number of terminals and charging times. The proposed EVCSI is validated using the CymDist software. The computational complexity of the model is NP-hard due to multiple variables and constraints.
Article
Education & Educational Research
Andrea Cueva, Esteban Inga
Summary: Technology development has improved the training of teachers in educational and technological tools, leading to integration of technology in the educational environment. This study focuses on using Information and Communication Technologies (ICT) in the Flipped Learning Model (FL) to enhance student motivation and learning. The research shows which ICTs are most used and beneficial for significant learning, emphasizing the importance of integrating ICT and Flipped Learning in educational communities to innovate the teaching-learning process.
EDUCATION SCIENCES
(2022)