Saved Queries

The treatment of moving objects in simultaneous localization and mapping (SLAM) is a key challenge in contemporary robotics. In this paper, we propose an extension of the EKF-SLAM algorithm that incorporates moving objects into the estimation process, which we term KISS. We have extended the robotic vision toolbox to analyze the influence of moving objects in simulations. Two linear and one nonlinear motion models are used to represent the moving objects. The observation model remains the same for all objects. The proposed model is evaluated against an implementation of the state-of-the-art formulation for moving object tracking, DATMO. We investigate increasing numbers of static landmarks and dynamic objects to demonstrate the impact on the algorithm and compare it with cases where a moving object is mistakenly integrated as a static landmark (false negative) and a static landmark as a moving object (false positive). In practice, distances to dynamic objects are important, and we propose the safety–distance–error metric to evaluate the difference between the true and estimated distances to a dynamic object. The results show that false positives have a negligible impact on map distortion and ATE with increasing static landmarks, while false negatives significantly distort maps and degrade performance metrics. Explicitly modeling dynamic objects not only performs comparably in terms of map distortion and ATE but also enables more accurate tracking of dynamic objects with a lower safety–distance–error than DATMO. We recommend that researchers model objects with uncertain motion using a simple constant position model, hence we name our contribution Keep it Static SLAMMOT. We hope this work will provide valuable data points and insights for future research into integrating moving objects into SLAM algorithms. Full article

(This article belongs to the Special Issue Sensor Fusion Applications for Navigation and Indoor Positioning)

18 pages, 1398 KiB

Open AccessArticle

Use of Threshold Median Adjustment to Achieve Accurate Current Balancing of Interleaved Buck Converter with Constant Frequency Hysteresis Control

by Liangliang Lu, Qidong Li, Yuxiang Yang, Yuchao Huang, Zeli Li and Desheng Zhang

Electronics 2024, 13(17), 3521; https://doi.org/10.3390/electronics13173521 (registering DOI) - 4 Sep 2024

Abstract

This paper proposes a current balancing loop that is obtained using the threshold median adjustment (TMA-CBL) to achieve the accurate current balancing of an interleaved constant frequency hysteresis (CFH) buck converter. The CFH control is implemented with a frequency phase loop based on a threshold width adjustment (TWA-FPL). To ensure the loop’s stability and minimize the steady-state error, a multi-phase, coupled, small-signal model (MPC-SSM) is derived with a consideration of the coupling effect among the multiple phases. Furthermore, the current balancing error is analyzed in detail, with a consideration of the sensing resistance deviations in the loop. Finally, based on a 180 nm BCD process, a four-phase interleaved buck converter is fabricated to verify the effectiveness of the proposed TMA-CBL. The maximum current balancing error is within 0.68% when the sensing resistors are deviated by 5%. Full article

(This article belongs to the Special Issue Control and Optimization of Power Converters and Drives)

14 pages, 628 KiB

Open AccessArticle

Analysis of the Distillation Column of a Catalytic Cracking Unit Using Fuzzy Input Information

by Dinara Kozhakhmetova, Samal Kaliyeva, Laura Sugurova, Zharkynay Sugur, Ryszard Wójtowicz and Tursynkhan Zhylkybayev

Energies 2024, 17(17), 4446; https://doi.org/10.3390/en17174446 (registering DOI) - 4 Sep 2024

Abstract

The aim of this work is to analyze and model the performance of the distillation column of a catalytic cracking plant using fuzzy initial information. A system of mathematical models of the studied columns was developed, and we discussed the issues of modeling the distillation column of a catalytic cracking plant operating in conditions of fuzzy initial information. The system of mathematical models of the studied columns was developed on the basis of statistical and fuzzy information. The mathematical models of columns K-1, K-2 and K-3 were identified with regression and fuzzy regression equations, i.e., combined models of the main columns of the catalytic cracking plant were constructed. The purpose of this study was to create an optimal control system for the distillation column of a catalytic cracking unit using a mathematical model of the process. The results obtained in this work can be helpful during the design, modernization and optimization of equipment and installations, especially those used in the chemical and petrochemical industries. They can be useful both from a scientific and practical point of view, and they are also significant in terms of environmental protection, economy and mechanical engineering. Full article

(This article belongs to the Section A4: Bio-Energy)

19 pages, 1373 KiB

Open AccessArticle

DRA-UNet for Coal Mining Ground Surface Crack Delineation with UAV High-Resolution Images

by Wei Wang, Weibing Du, Xiangyang Song, Sushe Chen, Haifeng Zhou, Hebing Zhang, Youfeng Zou, Junlin Zhu and Chaoying Cheng

Sensors 2024, 24(17), 5760; https://doi.org/10.3390/s24175760 (registering DOI) - 4 Sep 2024

Abstract

Coal mining in the Loess Plateau can very easily generate ground cracks, and these cracks can immediately result in ventilation trouble under the mine shaft, runoff disturbance, and vegetation destruction. Advanced UAV (Unmanned Aerial Vehicle) high-resolution mapping and DL (Deep Learning) are introduced as the key methods to quickly delineate coal mining ground surface cracks for disaster prevention. Firstly, the dataset named the Ground Cracks of Coal Mining Area Unmanned Aerial Vehicle (GCCMA-UAV) is built, with a ground resolution of 3 cm, which is suitable to make a 1:500 thematic map of the ground crack. This GCCMA-UAV dataset includes 6280 images of ground cracks, and the size of the imagery is 256 × 256 pixels. Secondly, the DRA-UNet model is built effectively for coal mining ground surface crack delineation. This DRA-UNet model is an improved UNet DL model, which mainly includes the DAM (Dual Dttention Dechanism) module, the RN (residual network) module, and the ASPP (Atrous Spatial Pyramid Pooling) module. The DRA-UNet model shows the highest recall rate of 77.29% when the DRA-UNet was compared with other similar DL models, such as DeepLabV3+, SegNet, PSPNet, and so on. DRA-UNet also has other relatively reliable indicators; the precision rate is 84.92% and the F1 score is 78.87%. Finally, DRA-UNet is applied to delineate cracks on a DOM (Digital Orthophoto Map) of 3 km² in the mining workface area, with a ground resolution of 3 cm. There were 4903 cracks that were delineated from the DOM in the Huojitu Coal Mine Shaft. This DRA-UNet model effectively improves the efficiency of crack delineation. Full article

(This article belongs to the Special Issue Smart Image Recognition and Detection Sensors)

16 pages, 1409 KiB

Open AccessArticle

Sustainability of Automated Manufacturing Systems with Resources by Means of Their Deadlock Prevention

by František Čapkovič

Electronics 2024, 13(17), 3517; https://doi.org/10.3390/electronics13173517 (registering DOI) - 4 Sep 2024

Abstract

This paper is devoted to Petri net (PN)-based models of automated manufacturing systems (AMSs) with resources in order to prevent deadlocks in them. Their sustainability can be seen as the result of their deadlock freeness, leading to correct and fluent production, because AMSs with deadlocks work neither correctly nor fluently, need reconstruction and cause downtime in production. The paradigm of such PN models, S³PRs (systems of simple sequential processes with resources), is well known from the deadlock prevention point of view. Here, an extended S³PR (ES3PR) will be explored, with respect to its modelling and deadlock prevention. While in the case of S³PRs, ordinary Petri nets (OPNs) are used for these aims, here, for ES³PRs, generalized Petri nets (GPNs) are used. The reason for such a procedure is the possible presence of multiplex-directed arcs in the structure of PN models of AMSs. The significant alternation is that while, in the former case, the elementary siphons and dependent ones are sufficient for supervisor synthesis, here, in the later case, the GPNs and their siphons have to satisfy the max cs property. Full article

►▼ Show Figures

Figure 1

21 pages, 6811 KiB

Open AccessArticle

Attenuation Capacity of a Multi-Cylindrical Floating Breakwater

by Luca Martinelli, Omar Mohamad, Matteo Volpato, Claes Eskilsson and Manuele Aufiero

J. Mar. Sci. Eng. 2024, 12(9), 1550; https://doi.org/10.3390/jmse12091550 (registering DOI) - 4 Sep 2024

Abstract

Floating breakwaters (FBs) are frequently used to protect marinas, fisheries, or other bodies of water subject to wave attacks of moderate intensity. New forms of FBs are frequently introduced and investigated in the literature as a consequence of technological advancements. In particular, a new possibility is offered by High-Density Polyethylene (HDPE) by extruding pipes of large diameters (e.g., 2.5 m in diameter) and with virtually no limit in length (hundreds of meters). By connecting two or three such pipes in a vertical layout, a novel low-cost floating breakwater with deep draft is devised. This note investigates numerically and experimentally the efficiency of this type of multi-cylindrical FBs in evaluating different geometries and aims at finding design guidelines. Due to the extraordinary length of the breakwater, the investigation is carried out in two dimensions. The 2D numerical model is based on the solution of the rigid body motion in the frequency domain, where the hydrodynamic forces are evaluated (thanks to a linear potential flow model), and the mooring forces do not include dynamic effects nor drag on the lines. The numerical predictions are compared to the results of a 1:10 scale experimental investigation. An atypical shape of the wave transmission (

k_{t}

) curve is found, with a very low minimum in correspondence with the heave resonance frequency. The results essentially point out the influence of the position of the gravity center, the stiffness, and the mutual distance among cylinders on

k_{t}

. Full article

(This article belongs to the Special Issue Coastal Engineering: Sustainability and New Technologies, 2nd Edition)

►▼ Show Figures

Figure 1

14 pages, 1789 KiB

Open AccessArticle

4D Embedded Rotating Black Hole as a Particle Accelerator in the Presence of Magnetic Fields

by Abraão J. S. Capistrano, Carlos Henrique Coimbra-Araújo and Rita de Cássia dos Anjos

Universe 2024, 10(9), 355; https://doi.org/10.3390/universe10090355 (registering DOI) - 4 Sep 2024

Abstract

We analyze a rotating black hole (BH) in a four-dimensional space-time embedded in five-dimensional flat bulk. In Boyer–Lindquist coordinates, we use a generic extension of the Kerr metric by the line element of Gürses–Gürsey metric. We discuss their horizon properties and shadow cast which is tailored by the influence of the extrinsic curvature. By means of the model based on the Nash–Greene theorem, we analyze the Gürses–Gürsey metric embedded in five dimensions acting as a rotating “charged” BH which may be regarded as a source of ultrahigh-energy cosmic rays (UHECRs). We also show that this type of BH presents a different structure of the accretion disk which is modified by the extrinsic curvature leading to an enlargement of the photons ring and an increase in the BH’s inner shadow. In the presence of a magnetic field, our initial results suggest that such BHs may be efficient free-test particle accelerators orbiting the inner stable circular orbit (ISCO). Full article

(This article belongs to the Collection Open Questions in Black Hole Physics)

►▼ Show Figures

Figure 1

17 pages, 3507 KiB

Open AccessArticle

Robust Text-to-Cypher Using Combination of BERT, GraphSAGE, and Transformer (CoBGT) Model

by Quoc-Bao-Huy Tran, Aagha Abdul Waheed and Sun-Tae Chung

Appl. Sci. 2024, 14(17), 7881; https://doi.org/10.3390/app14177881 (registering DOI) - 4 Sep 2024

Abstract

Graph databases have become essential for managing and analyzing complex data relationships, with Neo4j emerging as a leading player in this domain. Neo4j, a high-performance NoSQL graph database, excels in efficiently handling connected data, offering powerful querying capabilities through its Cypher query language. However, due to Cypher’s complexities, making it more accessible for nonexpert users requires translating natural language queries into Cypher. Thus, in this paper, we propose a text-to-Cypher model to effectively translate natural language queries into Cypher. In our proposed model, we combine several methods to enable nonexpert users to interact with graph databases using the English language. Our approach includes three modules: key-value extraction, relation–properties prediction, and Cypher query generation. For key-value extraction and relation–properties prediction, we leverage BERT and GraphSAGE to extract features from natural language. Finally, we use a Transformer model to generate the Cypher query from these features. Additionally, due to the lack of text-to-Cypher datasets, we introduced a new dataset that contains English questions querying information within a graph database, paired with corresponding Cypher query ground truths. This dataset aids future model learning, validation, and comparison on text-to-Cypher task. Through experiments and evaluations, we demonstrate that our model achieves high accuracy and efficiency when comparing with some well-known seq2seq model such as T5 and GPT2, with an 87.1% exact match score on the dataset. Full article

►▼ Show Figures

Figure 1

18 pages, 5847 KiB

Open AccessArticle

Nonlinear and Threshold Effects of the Built Environment on Dockless Bike-Sharing

by Ming Chen, Ting Wang, Zongshi Liu, Ye Li and Meiting Tu

Sustainability 2024, 16(17), 7690; https://doi.org/10.3390/su16177690 (registering DOI) - 4 Sep 2024

Abstract

Dockless bike-sharing mobility brings considerable benefits to building low-carbon transportation. However, the operators often rush to seize the market and regulate the services without a good knowledge of this new mobility option, which results in unreasonable layout and management of shared bicycles. Therefore, it is meaningful to explore the relationship between the built environment and bike-sharing ridership. This study proposes a novel framework integrated with the extreme gradient boosting tree model to evaluate the impacts and threshold effects of the built environment on the origin–destination bike-sharing ridership. The results show that most built environment features have strong nonlinear effects on the bike-sharing ridership. The bus density, the industrial ratio, the local population density, and the subway density are the key explanatory variables impacting the bike-sharing ridership. The threshold effects of the built environment are explored based on partial dependence plots, which could improve the bike-sharing system and provide policy implications for green travel and sustainable transportation. Full article

(This article belongs to the Special Issue Artificial Intelligence in Sustainable Transportation)

►▼ Show Figures

Figure 1

19 pages, 5599 KiB

Open AccessArticle

Investigating the Anti-Inflammatory, Analgesic, and Chondroprotective Effects of Gynostemma pentaphyllum (Thunb.) Makino in Osteoarthritis: An In Vitro and In Vivo Study

by Hee-Geun Jo, Chae Yun Baek, Yeseul Hwang, Eunhye Baek, Chanyoon Park, Ho Sueb Song and Donghun Lee

Int. J. Mol. Sci. 2024, 25(17), 9594; https://doi.org/10.3390/ijms25179594 (registering DOI) - 4 Sep 2024

Abstract

Osteoarthritis (OA) is an age-related disease characterized by inflammation, pain, articular cartilage damage, synovitis, and irreversible disability. Gynostemma pentaphyllum (Thunb.) Makino (GP), a herbal medicine traditionally used in East Asia for its anti-inflammatory properties, was investigated for its potential to modulate OA pathology and symptoms. This study evaluated GP’s efficacy in inhibiting pain, functional decline, and cartilage destruction in monosodium iodoacetate-induced OA and acetic acid-induced writhing models. Additionally, the effects of GP on OA-related inflammatory targets were assessed via mRNA and protein expression in rat knee cartilage and lipopolysaccharide-induced RAW 264.7 cells. The GP group demonstrated significant pain relief, functional improvement, and cartilage protection. Notably, GP inhibited key inflammatory mediators, including interleukin (IL)-1β, IL-6, matrix metalloproteinases (MMP)-3 and MMP-13, cyclooxygenase-2, and prostaglandin E receptor 2, surpassing the effects of active controls. These findings suggest that GP is a promising candidate for disease-modifying OA drugs and warrants further comprehensive studies. Full article

(This article belongs to the Special Issue New Pharmacological Insights on Natural Macromolecules and Natural Small Molecules)

►▼ Show Figures

Graphical abstract

22 pages, 5300 KiB

Open AccessArticle

Effect of Rubber Aggregates on Early-Age Mechanical Properties and Deformation Behaviors of Cement Mortar

by Gaowang Zhang, Hao Du, Junmin Li and Jie Yuan

Buildings 2024, 14(9), 2787; https://doi.org/10.3390/buildings14092787 - 4 Sep 2024

Abstract

Rubberized cement-based materials are widely utilized because of their good ductility, impact resistance, and fatigue resistance. This research investigated the effect of the rubber aggregates content, particle size of rubber aggregates, and water–cement ratio on the early-age mechanical properties and deformation behaviors of mortar through laboratory tests, and strength reduction coefficient fitting models were established according to the testing results. The results show that the compressive strength growth rate of cement mortar is about 15% slower than that of flexural strength. The existence of rubber aggregates lowers the strength increase rate of mortar. The reduction coefficient of strength decreases with increasing rubber aggregates content and increases with the age of mortar. Increasing rubber aggregates content and decreasing particle size of rubber aggregate can lower the autogenous shrinkage in the initial stage, but the autogenous shrinkage of the later stage increases as the rubber aggregates content increases, with a turning point between 30 h and 50 h. After 3 days, the dry shrinkage of mortar accounts for about 70–80% of the total shrinkage, and it increases with higher rubber aggregate content, smaller particle size of rubber aggregates, and higher water–cement ratios. Full article

(This article belongs to the Special Issue Advances in Composite Construction in Civil Engineering)

►▼ Show Figures

Figure 1

1 pages, 136 KiB

Open AccessCorrection

Correction: Beckmann et al. Semantic Integration of BPMN Models and FHIR Data to Enable Personalized Decision Support for Malignant Melanoma. Information 2023, 14, 649

by Catharina Lena Beckmann, Daniel Keuchel, Wa Ode Iin Arliani Soleman, Sylvia Nürnberg and Britta Böckmann

Information 2024, 15(9), 541; https://doi.org/10.3390/info15090541 (registering DOI) - 4 Sep 2024

Abstract

In the original publication [...] Full article

16 pages, 3838 KiB

Open AccessArticle

The Generation and Evolution of High-Order Wheel Polygonal Wear from the Effects of Wheelset Rotation

by Yahong Dong and Shuqian Cao

Lubricants 2024, 12(9), 313; https://doi.org/10.3390/lubricants12090313 - 4 Sep 2024

Abstract

Polygonal wear affects driving safety and drastically shortens a wheel’s life. This work establishes a wheel–rail coupled system’s rotor dynamics model and a wheel polygonal wear model, taking into account the wheelset’s flexibility, the effect of the wheelset rotation, and the initial wheel polygon. The energy approach is applied to study the stability of the self-excited vibration of a wheel–rail coupled system. The wheel polygonal wear generation and evolution mechanism is revealed, along with the impact of vehicle and rail characteristics on a wheel’s high-order polygon. The findings demonstrate that wheel polygonal wear must occur in order for the wheel–rail system to experience self-excited vibration, which is brought on by a feedback mechanism dominated by creepage velocity. Additionally, the Hopf bifurcation characteristic is displayed by the wheel–rail system’s self-excited vibration. Wheel polygonal wear is characterized by “fixed frequency and integer division”, and the wheelset flexibility largely determines the fixed frequency of high-order polygonal wear, which is mostly unaffected by the suspension characteristics of the vehicle. By decreasing the tire load, increasing the wheelset’s damping, and choosing a variable running speed, the progression of polygonal wear on wheels can be prevented. Future investigations on the suppression of wheel polygonal wear evolution can be guided by the results. Full article

►▼ Show Figures

Figure 1

25 pages, 788 KiB

Open AccessReview

Subcellular Drug Distribution: Exploring Organelle-Specific Characteristics for Enhanced Therapeutic Efficacy

by Xin Liu, Miaomiao Li and Sukyung Woo

Pharmaceutics 2024, 16(9), 1167; https://doi.org/10.3390/pharmaceutics16091167 - 4 Sep 2024

Abstract

The efficacy and potential toxicity of drug treatments depends on the drug concentration at its site of action, intricately linked to its distribution within diverse organelles of mammalian cells. These organelles, including the nucleus, endosome, lysosome, mitochondria, endoplasmic reticulum, Golgi apparatus, lipid droplets, exosomes, and membrane-less structures, create distinct sub-compartments within the cell, each with unique biological features. Certain structures within these sub-compartments possess the ability to selectively accumulate or exclude drugs based on their physicochemical attributes, directly impacting drug efficacy. Under pathological conditions, such as cancer, many cells undergo dynamic alterations in subcellular organelles, leading to changes in the active concentration of drugs. A mechanistic and quantitative understanding of how organelle characteristics and abundance alter drug partition coefficients is crucial. This review explores biological factors and physicochemical properties influencing subcellular drug distribution, alongside strategies for modulation to enhance efficacy. Additionally, we discuss physiologically based computational models for subcellular drug distribution, providing a quantifiable means to simulate and predict drug distribution at the subcellular level, with the potential to optimize drug development strategies. Full article

►▼ Show Figures

Figure 1

20 pages, 1804 KiB

Open AccessArticle

Modeling and Multi-Objective Optimization Design of High-Speed on/off Valve System

by Yexin Ma, Dongjie Wang and Yang Shen

Appl. Sci. 2024, 14(17), 7879; https://doi.org/10.3390/app14177879 - 4 Sep 2024

Abstract

The design of the high-speed on/off valve is challenging due to the interrelated structural parameters of its driving actuator. Hence, this study proposes a multi-objective optimization approach that integrates a backpropagation neural network and artificial fish swarm algorithm optimization techniques to accurately model the electromagnetic solenoid structure. The backpropagation neural network is fitted and trained using simulation data to obtain a reduced-order model of the system, enabling the precise prediction of the system’s output based on the input structural parameters. By employing the artificial fish swarm algorithms, with optimization objectives focusing on the valve’s opening and closing times, a Pareto optimal solution set comprising 30 solutions is generated. Utilizing the optimized structural parameters, a prototype is manufactured and an experimental setup is constructed to verify the dynamic characteristics and flow pressure drop. The high-speed on/off valve achieves an approximate opening and closing time of 3 ms. Notably, the system output predicted using the backpropagation neural network (BPNN) exhibits consistency with the experimental findings, providing a reliable alternative to mathematical modeling. Full article

Show export options Show export options

Select all

Export citation of selected articles as:

Error

Oops... you haven't selected anything for export.

Displaying article 1-50 on page 1 of 2000.

Go to page 1 2 3 4 5

Search Results (400,831)

Further Information

Guidelines

MDPI Initiatives

Follow MDPI