Article
Engineering, Aerospace
Tomasz Kur, Maciej Kalarus
Summary: Inter-Satellite Links (ISL) are seen as a key technology to enhance the accuracy of the Global Navigation Satellite System (GNSS) and navigation satellites orbit determination. This study evaluates the advantages of ISLs, particularly focusing on Galileo, in precise orbit determination and satellite clock estimation, paving the way for more advanced processing and algorithm development. The analysis of various ISL connectivity schemes is presented in the context of the precise orbit determination (POD) based on weighted least squares adjustment, showing improvements in orbit error reduction and clock estimation accuracy when using ISLs.
ADVANCES IN SPACE RESEARCH
(2021)
Article
Computer Science, Information Systems
Gregor Cerar, Halil Yetgin, Mihael Mohorcic, Carolina Fortuna
Summary: This article investigates link quality estimators developed from empirical data, with a focus on models using machine learning algorithms. The ML-based LQE models are analyzed from two perspectives using performance data: addressing quality requirements of applications and approaching standard design steps in the ML community.
IEEE COMMUNICATIONS SURVEYS AND TUTORIALS
(2021)
Article
Engineering, Electrical & Electronic
Xia Xiao, Qun Yu, Qinwei Li, Hang Song, Takamaro Kikkawa
Summary: The research introduces a noninvasive method for accurately estimating blood glucose concentration using an improved neural network model and hybrid optimization. Experimental results show that this method significantly improves estimation accuracy.
IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT
(2021)
Article
Computer Science, Information Systems
Mu He, Jian Shu
Summary: The paper proposes a link quality estimation model based on deep forest in wireless sensor networks. By combining stratified sampling with cascade forest, the feature extraction performance is improved, leading to better estimation accuracy and stability of link quality.
Article
Computer Science, Information Systems
Weiwei Miao, Zhengyang Ding, Hao Tang, Zeng Zeng, Mingxuan Zhang, Shaqian Zhang
Summary: Link quality estimation is crucial for efficient routing and energy consumption in Wireless Sensor Networks. Existing approaches relying on physical layer measurements face challenges in accurately estimating link quality. This paper introduces a novel method, SeqLQE, using system metrics to predict link quality with superior performance compared to linear models.
Article
Computer Science, Information Systems
Linlan Liu, Hui Lv, Jiangbo Xu, Jian Shu
Summary: The study presents a link quality estimation model based on improved weighted extreme learning machine for link quality estimation in wireless sensor networks. Experimental results demonstrate that this model is more effective in different scenarios compared to conventional models.
Article
Computer Science, Information Systems
Konstantin Muranov, Md Atiqul Islam, Besma Smida, Natasha Devroye
Summary: Two new methods for digital mitigation of non-linear Self-Interference (SI) signal in Full-Duplex (FD) relay link are proposed and evaluated, utilizing Deep Neural Networks (DNN) for reconstruction of non-linear SI components. These methods significantly reduce or eliminate on-line training by utilizing transfer learning and decoupling the reconstruction of non-linear SI signal from the estimation of the SI propagation channel.
IEEE WIRELESS COMMUNICATIONS LETTERS
(2021)
Article
Engineering, Electrical & Electronic
Dong Xia, Linjiang Zheng, Yi Tang, Xiaolin Cai, Li Chen, Weining Liu, Dihua Sun
Summary: This study utilizes ERI data to conduct traffic estimation and simulation, constructs the MGCN travel time estimation model, and achieves superior results in traffic simulation.
IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY
(2022)
Article
Computer Science, Information Systems
Arash Moradi, Jalil Yaghoobi, Firuz Zare
Summary: This paper proposes a new mathematical model for estimating the inverter-side current harmonics in an ASD. The model takes into account the load-side currents and the voltage ripple across the DC-link, resulting in higher accuracy compared to existing methods. The effectiveness of the proposed model is validated through experimental and simulation results.
Article
Computer Science, Information Systems
Shahid Iqbal, Adnan Ahmed, Mohammad Siraj, Majid Al Tamimi, Ali Raza Bhangwar, Pardeep Kumar
Summary: Technological advancements and miniaturization of sensor have enabled the use of tiny size sensors nodes to monitor patients' physiological data in real-time at low cost. However, short range wireless nodes and body movements cause frequent topological changes and network partitioning, leading to delays and loss of critical patient data in wireless body sensor networks (WBSNs). This paper proposes a Predicting routing protocol PLQE to address reliable data transmission and network partitioning due to node mobility. Simulation results show that the proposed scheme outperforms existing routing protocols in terms of packet delivery ratio, end-to-end delay, throughput, and normalized routing load.
Article
Telecommunications
Chao Meng
Summary: This paper proposes a novel method for more accurate estimation of link quality and proves the accuracy of the calculation results using probability theory. In addition, it provides a routing algorithm and improvement algorithm based on link quality estimation.
WIRELESS PERSONAL COMMUNICATIONS
(2022)
Article
Engineering, Electrical & Electronic
Jianxiong Li, Xingkai Shao, Jie Li, Lijun Ge
Summary: This paper introduces a direction of arrival (DOA) estimation method based on residual neural networks (ResNets), which is poorly adapted in the case of antenna array defects. The proposed method improves adaptability to defects and generalization ability to unknown scenes. The method divides received signals into corresponding subregions to relieve the generalization burden, and uses the output of a spatial classification network (SCN) as input for parallel ResNets. The results are combined to obtain the estimated direction of the signal.
CIRCUITS SYSTEMS AND SIGNAL PROCESSING
(2022)
Article
Automation & Control Systems
Chaoqing Jia, Jun Hu, Hongjian Liu, Junhua Du, Shuyang Feng
Summary: This paper focuses on the recursive state estimation (RSE) problem in nonlinear complex networks (CNs) with uncertain inner coupling, random link failures, and packet disorders. The paper proposes an RSE approach based on mean-square error, which obtains a suboptimal upper bound of the state estimation error covariance considering uncertain inner coupling, random link failures, and packet disorders. Additionally, the paper provides a sufficient condition for the uniform boundedness of state estimation error in the mean-square sense and validates the proposed RSE approach through a numerical experiment.
Article
Engineering, Electrical & Electronic
Sudesh Pahal, Neeru Rathee, Brahmjit Singh
Summary: The evolution of wireless networks towards high mobility has resulted in the concept of connecting vehicles. Wireless link quality is crucial for successful communication among vehicles. Data-driven approaches are applied to estimate the dynamic attributes of vehicular networks. This paper proposes a deep learning model based on an artificial neural network technique to predict wireless link quality in vehicular networks.
IETE JOURNAL OF RESEARCH
(2023)
Article
Transportation
Hao Fu, William H. K. Lam, H. W. Ho, Wei Ma
Summary: This study proposes a method to optimize the locations of multi-type traffic sensors in order to improve the accuracy of link travel time estimation. By integrating data from different types of sensors, link travel times in an entire road network can be better estimated. The method takes into account constraints such as total financial budget, measurement errors, and cost ratio.
TRANSPORTMETRICA B-TRANSPORT DYNAMICS
(2023)
Article
Polymer Science
Farhad Shahsavan, Mario Beiner, Kay Saalwaechter
Summary: H-1 double-quantum NMR has been established as a suitable molecular-rheology technique to study chain dynamics and entanglement densities in polymer melts. Analysis of data shows a correlation between NMR results and cross-linking extent, with qualitative consistency between microscopic and macroscopic observables established through time-temperature superposition. The NMR method allows for extension of the frequency range of shear rheology, providing valuable insights compared to traditional gel content measurements.
JOURNAL OF POLYMER SCIENCE
(2022)
Article
Polymer Science
Zahra Mohammadyarloo, Jens-Uwe Sommer
Summary: We studied the phase segregation in polymer solutions in the presence of a co-nonsolvent using molecular dynamics simulations. Increasing the amount of co-nonsolvent results in a condensation of the polymer-co-nonsolvent phase, followed by a re-entry behavior at higher concentrations. The conformation statistics of the polymer chains were found to be consistent with the behavior in semidilute solution at the given concentration.
Article
Chemistry, Physical
Ankush Checkervarty, Jens-Uwe Sommer, Marco Werner
Summary: The Bond Fluctuation Model (BFM) is a versatile method for simulating polymers, membranes, and soft matter. In this study, an implicit solvent model based on an artificial neural network (NN) was introduced, which was trained with BFM simulation data for single homopolymers in an explicit solvent. It was demonstrated that the NN-based simulations can reproduce the universal properties of polymers under varying solvent conditions.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Review
Polymer Science
Mostafa Ahmadi, Amir Jangizehi, Kay Saalwaechter, Sebastian Seiffert
Summary: Transient structures based on associative polymers have potential applications in drug delivery, tissue engineering, and electronics. However, the phase separation of polar pairwise associations from nonpolar polymer chains often leads to junction aggregation, which affects the network structure and dynamics. The knowledge of the effect of design parameters on aggregates and their consequent effects on material properties is limited.
MACROMOLECULAR CHEMISTRY AND PHYSICS
(2023)
Article
Chemistry, Physical
Mostafa Ahmadi, Lucas Loeser, Gerard Pareras, Albert Poater, Kay Saalwaechter, Sebastian Seiffert
Summary: The properties of polymer networks are influenced by the presence of connectivity defects like loops and dangling ends. Transient polymer networks based on metallo-supramolecular polymer networks and hindrance can self-sort to develop networks with fewer defects. By using heteroleptic complexes and adjusting the coordination geometry preference, we can control the self-sorting process and reduce the formation of primary loops and dangling ends. Our results show that copper(I) can adopt the desired geometry requirements and create a network with the least number of defects.
CHEMISTRY OF MATERIALS
(2023)
Article
Polymer Science
M. Azevedo, A. -M Monks, R. C. Kerschbaumer, S. Schloegl, K. Saalwaechter, M. Walluch, G. Consolati, C. Holzer
Summary: In this study, the crosslinking reaction of solid silicone rubber with dicumylperoxide (DCP) was investigated. It was found that the concentration of DCP had limited influence on the molecular dynamics of the network, which was mainly dominated by entanglements. Differences were also observed in the crystallization ability after crosslinking, with higher crosslinking points leading to lower crystallinity and less stable crystallites.
JOURNAL OF APPLIED POLYMER SCIENCE
(2023)
Article
Chemistry, Physical
I. Abdoli, H. Loewen, J. -U. Sommer, A. Sharma
Summary: Kramers's theory accurately describes the probability of a thermally activated Brownian particle escaping a potential well, with escape time exponentially decreasing as the barrier height increases. In the presence of a charged particle under a Lorentz force due to an external magnetic field, the dynamics slow down. Our study demonstrates that the barrier height can be effectively modified when a charged particle is exposed to a vortex flow. When combined with a magnetic field, the vortex either pushes the particle radially outside or inside, influencing the particle's escape behavior.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Multidisciplinary
Simon Schubotz, Quinn A. Besford, Saghar Nazari, Petra Uhlmann, Eva Bittrich, Jens-Uwe Sommer, Gunter K. Auernhammer
Summary: Polymer brushes, which are polymer chains tethered to substrates, are highly sensitive to adaptation and can undergo changes in swelling, adsorption, and reorientation due to the surrounding liquid or atmosphere. This study analyzes how the atmosphere surrounding an aqueous droplet affects the contact angle on polymer brush surfaces. The use of a coaxial needle allows for reliable measurement of wetting properties even when the droplet and atmosphere are not in equilibrium. It was found that the water contact angle of a sample can be significantly influenced by the composition and humidity of the surrounding atmosphere.
Review
Polymer Science
Kay Saalwaechter, Thomas Thurn-Albrecht, Wolfgang Paul
Summary: This review focuses on recent developments in elucidating the formation of semicrystalline structures in bulk polymer melts, with an emphasis on less systematically studied factors. These factors include the influence of chain motion through the crystallites on the final crystallite thickness, and the effects of entanglements on crystal growth and crystallinity reduction. Theoretical interest lies in understanding the thermodynamic driving forces of polymer crystallization, providing a theoretical background for determining resulting structures in experiments based on kinetic limitations.
MACROMOLECULAR CHEMISTRY AND PHYSICS
(2023)
Article
Polymer Science
Qiang Yu, Afiq Anuar, Albrecht Petzold, Jens Balko, Kay Saalwaechter, Thomas Thurn-Albrecht
Summary: A detailed analysis of polybutylene succinate (PBS), a biodegradable polyester, was conducted using nuclear magnetic resonance (NMR) and small-angle X-ray scattering. It was found that PBS has a high crystallinity and a typical morphology of lamellar crystals with a broad thickness distribution of the amorphous interlayers. The mechanical properties of PBS were also found to be enhanced by additional insertion crystallization during cooling.
MACROMOLECULAR CHEMISTRY AND PHYSICS
(2023)
Article
Multidisciplinary Sciences
Jens Friedrichs, Ralf Helbig, Julia Hilsenbeck, Prithvi Raj Pandey, Jens-Uwe Sommer, Lars David Renner, Tilo Pompe, Carsten Werner
Summary: Control of adhesion is an important phenomenon in living matter, especially in terms of technological translation. We found that entropic repulsion caused by interfacial orientational fluctuations of cholesterol layers restricts protein adsorption and bacterial adhesion. Our insights provide a new perspective on biointerfaces and may guide future material design in the regulation of adhesion.
Article
Polymer Science
K. S. Kumar, M. Lang
Summary: This article proposes a theoretical approximation method based on balance equations to study the microstructure and properties of reversible networks made of star polymers. The model extends the tree approximation (ideal networks) in terms of the formation of the smallest loops. Monte Carlo simulations are used to test the model networks with controlled formation of cyclic structures. Both irreversible and reversible networks develop a unique critical concentration c (crit) for gelation in the limit of high functionality f → ∞ of the star polymers when only pending loops are considered. Reversible networks prefer intramolecular reactions compared to irreversible systems, and odd-even effects appear at small f once pending loops are possible.
Editorial Material
Chemistry, Physical
Michael Lang
Summary: An approach to analyze the deformation behavior of polymer networks provides valuable structural information, enhancing our understanding of the elasticity of soft materials.
Article
Multidisciplinary Sciences
Zefan Wang, Mareen Schaller, Albrecht Petzold, Kay Saalwaechter, Thomas Thurn-Albrecht
Summary: Crystallization of polymers from entangled melts leads to the formation of semicrystalline materials with alternating crystalline and amorphous layers. While the factors controlling the thickness of the crystalline layers are well studied, the thickness of the amorphous layers lacks quantitative understanding. This study investigates the effect of entanglements on the semicrystalline morphology using model blends with reduced entanglement density, revealing a reduced thickness of the amorphous layers without significantly affecting the crystal thickness. A simple yet quantitative model is proposed to explain the observed behavior.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2023)
Article
Polymer Science
Carolin Bunk, Hartmut Komber, Michael Lang, Nora Fribiczer, Martin Geisler, Petr Formanek, Lothar Jakisch, Sebastian Seiffert, Brigitte Voit, Frank Boehme
Summary: In this study, two well-defined amphiphilic tetra-arm star block copolymers were prepared by a hetero-complementary linking reaction. The behavior of the two copolymers was studied in water, and it was found that spherical micelles formed at elevated temperatures for the copolymer with longer PEG arms. However, the copolymer with shorter PEG arms formed cloudy suspensions in water.
