Space Network Research Articles

Research on the integration of MEMS and reliable transmission of deep space networks based on time-sensitive networking

With the continuous deepening of human space exploration, deep space networks far away from Earth have emerged. Unlike traditional ground networks, they have the characteristics of frequent link interruptions and time extensions. Traditional data transmission mechanisms cannot be well applied in deep space networks. We propose a data transmission technology that integrates time-sensitive networking and artificial intelligence to address the contradiction between deterministic delay and differentiated service quality assurance in deep space networks and construct a micro electromechanical system (MEMS). Considering the differences in service quality due to different business requirements, data transmission in deep space networks is transformed into a mixed integer programming problem that minimizes transmission delay and maximizes link utilization and solved using artificial intelligence imitation learning. Experimental results have shown that the proposed algorithm has fast convergence, strong applicability, and can achieve reliable and efficient data transmission while meeting the requirements of higher priority data transmission. It can also significantly improve throughput.

Public Vitality-Driven Optimization of Urban Public Space Networks—A Case Study from Nanjing, China

Spontaneous recreational activities in public spaces are a vital source of public vitality. Given the similarity between the walking patterns of recreational crowds in public spaces and the movement of electrons on a two-dimensional circuit surface, this study combines big data from various sources to create an “electrical conductivity surface” that attracts and aggregates recreational crowds. Using current flow simulation, we generate the path selection preferences of people as they move across public spaces. The results reveal an uneven distribution of public spaces in Nanjing’s main urban area, with high-vitality areas mostly concentrated in the urban center. The core demand for enhancing public vitality lies is improving connectivity between multiple spaces. Based on this, the public space plan for Nanjing’s main urban area emphasizes overall connectivity by aligning with the natural landscape, thus linking the city’s green and gray infrastructure. In this study, we have assessed current public space services and their development potential from a number of different angles, developing a digital approach for optimizing the urban layout. We aim to provide a human-centric, bottom-up perspective to complement the top-down city planning and management approach. This will enable urban planners to make informed decisions for creating and managing more vibrant cities.

Cryptography is Rocket Science

Space networking has become an increasing area of development with the advent of commercial satellite networks such as those hosted by Starlink and Kuiper, and increased satellite and space presence by governments around the world. Yet, historically such network designs have not been made public, leading to limited formal cryptographic analysis of the security offered by them. One of the few public protocols used in space networking is the Bundle Protocol, which is secured by Bundle Protocol Security (BPSec), an Internet Engineering Task Force (IETF) standard. We undertake a first analysis of BPSec under its default security context, building a model of the secure channel security goals stated in the IETF standard, and note issues therein with message loss detection. We prove BPSec secure, and also provide a stronger construction, one that supports the Bundle Protocol's functionality goals while also ensuring destination awareness of missing message components.

Delay/Disruption Tolerant Networking Performance Characterization in Cislunar Relay Communication Architecture.

Future 7G/8G networks are expected to integrate both terrestrial Internet and space-based networks. Space networks, including inter-planetary Internet such as cislunar and deep-space networks, will become an integral part of future 7G/8G networks. Vehicle-to-everything (V2X) communication networks will also be a significant component of 7G/8G networks. Therefore, space networks will eventually integrate with V2X communication networks, with both space vehicles (or spacecrafts) and terrestrial vehicles involved. DTN is the only candidate networking technology for future heterogeneous space communication networks. In this work, we study possible concatenations of different DTN convergence layer protocol adapters (CLAs) over a cislunar relay communication architecture. We present a performance characterization of the concatenations of different CLAs and the associated data transport protocols in an experimental manner. The performance of different concatenations is compared over a typical primary and secondary cislunar relay architecture. The intent is to find out which network relay path and DTN protocol configuration has the best performance over the end-to-end cislunar path.

BRAIN CLEARANCE SYSTEM ALTERATION AND COGNITIVE DECLINE IN AFRICAN AMERICANS WITH POOR SLEEP QUALITY

Abstract African Americans have 2-3 times the prevalence of Alzheimer’s disease (AD) than Whites, making this a significant health disparity in the US. Healthy sleep plays a critical role in providing protection from cognitive decline and AD. Unfortunately, African Americans have significantly poorer indicators of sleep quality than Whites. Moreover, the mechanism whereby sleep drives AD and related cognitive decline is not well understood, in part because causal links are yet to be established by human studies. One possible mechanism linking sleep to AD is the glymphatic system, a network of perivascular spaces (PVS) that support waste clearance. This study used ultra-high field magnetic resonance imaging technology, novel PVS mapping technology, wrist actigraphy and sleep assessments, cognitive assessments and regression analysis to investigate how alteration of the glia-lymphatic system associated with sleep contributes to cognitive decline in 61 community-dwelling African Americans (age 45+). African American who slept more and spent more time in bed had a higher risk for cognitive impairment as indicated by lower MMSE scores. We also found that African Americans with larger PVS volume (more metabolic waste in the brain) had lower cognitive scores. The effect of sleep quality on cognitive status was mediated by PVS, such that African Americans who spent more time in bed had larger PVS (more waste and fluid) and lower cognitive scores. Findings from this study advance our understanding of the role of sleep and brain clearance in cognitive decline in African Americans, and identify PVS as a novel marker for cognitive decline.

К вопросу о необходимости криминализации скулшутинга

The article examines the causes and consequences of acts of violence in educational institutions. The authors analyze the sociocultural factors that contribute to the emergence of school shooting, such as aggression in the surrounding juvenile society and the influence of the media space and social networks. Psychological aspects are also discussed, including the condition of the victims and their environment. The study is based on data from cases that occurred in Russia and their comparison with international practice. Particular attention is paid to preventive measures and the need to introduce a separate article into the norms of criminal legislation for this crime. In conclusion, the importance of an integrated approach to solving the problem is emphasized. To implement these measures, educational institutions have begun to focus on safety measures for both students and employees of educational institutions, work is aimed at maintaining a healthy psychological and moral climate, educational work is carried out at meetings among teachers, students and their parents about the facts that should be paid attention to when teaching and raising children. Timely identification, provision of professional and psychological assistance to adolescents who are prone to committing acts of violence or committing any crime against life and health will prevent the onset of socially dangerous consequences both for others and for the schoolshooter himself. In order to ensure the public safety of the population, as well as the observance of public order, it is proposed to provide for the strictest liability for the socially dangerous act in question within the framework of criminal legislation. By the forces of the juvenile affairs units, together with the teaching staff of educational institutions, conducting preventive conversations with school-children and their parents on the presented topic, drawing attention to the behavior of students in an educational institution and directly in the team, will contribute to achieving this goal.

Emerging space communication and network technologies for 6G ubiquitous connectivity

Emerging space communication and network technologies for 6G ubiquitous connectivity

Io's tidal response precludes a shallow magma ocean.

Io experiences tidal deformation due to its eccentric orbit around Jupiter, which provides a primary energy source for Io's ongoing volcanic activity and infrared emission1. The amount of tidal energy dissipated within Io is enormous and has been hypothesized to support the large-scale melting of Io's interior and the formation of a global subsurface magma ocean. If Io has a shallow global magma ocean, its tidal deformation would be much larger than in the case of a more rigid, mostly solid interior2. Here we report the measurement of Io's tidal deformation, quantified by the gravitational tidal Love number k2, enabled by two recent flybys of the Juno spacecraft. By combining Juno3,4 and Galileo5-7 Doppler data from the Deep Space Network and astrometric observations, we recover Re(k2) of 0.125±0.047 (1σ) and the tidal dissipation parameter Q of 11.4±3.6 (1σ). These measurements confirm that a shallow global magma ocean in Io does not exist and are consistent with Io having a mostly solid mantle2. Our results indicate that tidal forces do not universally create global magma oceans, which may be prevented from forming due to rapid melt ascent, intrusion, and eruption8,9, so even strong tidal heating - like that expected on several known exoplanets and super-Earths10 - may not guarantee the formation of magma oceans on moons or planetary bodies.

Deep reinforcement learning for collision avoidance of autonomous ships in inland rivers

Due to the characteristics of large inertia, large time delay and non-linearity in ship motion, the manoeuvrability of ships is an important issue related to the safety of ship navigation. The manipulation of ships significantly affects the safety of ship navigation, and its importance will gradually increase with the development of autonomous ships (ASs). Due to the complexity of inland waterways and the density of ships, collisions are common. In this work, an autonomous learning framework with deep reinforcement learning (DRL) was constructed for ASs. The state space, action space, reward function and neural network structure of DRL were designed based on the AS's manoeuvring characteristics and control requirements. A deep deterministic policy gradient (DDPG) algorithm was then used to implement the controller. Finally, some representative route segments of an inland waterway were selected for simulation research based on a virtual simulation environment. The designed DRL controller was able to quickly converge from the training and learning process to meet the control requirements. The effectiveness of the DDPG algorithm was verified by comparisons with the experimental results. This study provides a reference for future research on collision-avoidance technology for ASs in inland rivers.

The last forty years of landscape design and planning

The chapter discusses the distinct branches of landscape architecture: landscape design of gardens, parks, urban open spaces, design of registered historic gardens, landscape planning, planning of local green space networks and spatial planning. Landscape design and planning, like architecture, responds to and is fundamentally dependent on the needs and expectations of society. It is therefore important to outline the main social processes of the last forty years.The chapter focuses on the landscape projects realised rather than on the plans, since it is the result of the design process, the completed project, that is most important. It tells us almost everything, about the times in which it was conceived and in which the designer, the client, the constructor and the users existed. The results and social impact of landscape design can be seen mainly in the completed work. There is usually a narrow professional interest in the plans that remain in the drawer.The results of landscape planning and green space planning at local level and spatial planning are only visible many years later, making it more difficult to follow the social impact. Therefore, in the case of landscape planning and green space planning at local and regional level, the chapter is limited to outlining only the trends over four decades.

Optimizing Bus Bridging Service Considering Passenger Transfer and Reneging Behavior

This paper addresses the design of bus bridging services in response to urban rail disruption, which plays a critical role in enhancing the resilience and sustainability of urban transportation systems. Specifically, it focuses on unplanned urban rail disruptions that result in temporary closure of line sections, including transfer stations. Under this “transfer scenario”, a heuristic-rule based method is firstly presented to generate candidate bus bridging routes. Non-parallel bridging routes are introduced to facilitate transfer passengers affected by the disruption. Meanwhile, the bridging stops visited by parallel routes are extended beyond the disrupted section, mitigating passenger congestion and bus bunching at turnover stations. Then, we propose an integrated optimization model that collaboratively addresses bus route selection and vehicle deployment issues. Capturing passenger reneging behavior, the model aims to maximize the number of served passengers with tolerable waiting times and minimize total passenger waiting times. A two-stage genetic algorithm is developed to solve the model, which incorporates a multi-agent simulation method to demonstrate dynamic passenger and bus flow within a time–space network. Finally, a case study is conducted to validate the effectiveness of the proposed methods. Sensitivity analyses are performed to explore the impacts of fleet size and route diversity on the overall bridging performance. The results offer valuable insights for transit agencies in designing bus bridging services under transfer scenarios, supporting sustainable urban mobility by promoting efficient public transit solutions that mitigate the social impacts of sudden service disruptions.

Tactical intent-driven autonomous air combat behavior generation method

With the rapid development and deep application of artificial intelligence, modern air combat is incrementally evolving towards intelligent combat. Although deep reinforcement learning algorithms have contributed to dramatic advances in in air combat, they still face challenges such as poor interpretability and weak transferability of adversarial strategies. In this regard, this paper proposes a tactical intent-driven method for autonomous air combat behaviour generation. Firstly, this paper explores the mapping relationship between optimal strategies and rewards, demonstrating the detrimental effects of the combination of sparse rewards and dense rewards on policy. Built around this, the decision-making process of pilot behavior is analyzed, and a reward mapping model from intent to behavior is established. Finally, to address the problems of poor stability and slow convergence speed of deep reinforcement learning algorithms in large-scale state-action spaces, the dueling-noisy-multi-step DQN algorithm is devised, which not only improves the accuracy of value function approximation but also enhances the efficiency of space exploration and network generalization. Through experiments, the conflicts between sparse rewards and dense rewards are demonstrated. The superior performance and stability of the proposed algorithm compared to other algorithms are captured by our empirical results. More intuitively, the strategies under different intents exhibit strong interpretability and flexibility, which can provide tactical support for intelligent decision-making in air combat.

Sex‐specific topological structure associated with dementia identified via latent space network analysis

Sex‐specific topological structure associated with dementia identified via latent space network analysis

Exploratory study on time-delayed excavator teleoperation in virtual lunar construction simulation: Task performance and operator behavior

Building sustainable habitats on the moon has been planned for decades. However, applying fully automated construction systems is still challenging in altered environments. Teleoperation, which is the remote control of the machine, can serve as an intermediate phase before achieving fully autonomous systems. Since the teleoperation between operators on the earth-ground and robots on the lunar surface introduces inevitable communication time delays under a deep space network system, it is important to understand its impact on task performance and operator behaviors in teleoperated construction tasks. This paper develops a simulated lunar environment for excavator teleoperation systems in virtual reality to examine task performance and operator behaviors in time delay conditions. The outcomes indicate that time delays significantly degrade task performance, and the operators modify their control strategies to cope with the time delay conditions. The findings will contribute to understanding human behaviors in time-delayed teleoperation of lunar construction tasks.

Cloud‐Edge Collaboration‐Based Multi‐Cluster System for Space‐Ground Integrated Network

ABSTRACTAs global informationization deepens, the importance of Space‐Ground Integrated Network (SGIN) as a new network architecture becomes increasingly prominent. SGIN combines the advantages of ground and space networks, enabling global information interconnection and sharing through various communication means such as satellites, drones, and ground stations. However, due to its complex network environment and diverse communication requirements, traditional network architectures struggle to meet its demands for efficiency, stability, and scalability. To address these challenges, we focus on the research, design, and implementation of a cloud‐edge collaboration‐based multi‐cluster system for SGIN. The goal is to construct an efficient, stable, and scalable network system capable of providing seamless global coverage and efficient communication within SGIN. We design a multi‐cluster system architecture based on container technology, leveraging cloud and edge computing techniques for dynamic resource allocation and efficient utilization. This architecture aims to meet the diverse network service requirements of ground terminals, enhancing responsiveness, efficiency, resilience, and reliability of network services. Additionally, we introduce a multipath data transmission mechanism to support the transfer of large‐scale data, such as remote sensing images. A simulation platform tailored for SGIN is developed, demonstrating the feasibility of the multi‐cluster system and the effectiveness of multipath data transmission.

Institutional resilience of club sport in an extreme context: collective dealing with the COVID-19 pandemic from an institutional work lens

ABSTRACT The COVID-19 pandemic has been an enormous challenge for individuals, organisations, and institutions as a collective of actors that constitute a field, such as club sport. In our paper, we define institutional resilience as a field’s capacity of collectively and successfully responding to the challenges of an extreme context. Following a qualitative empirical approach (content analysis of 19 interviews) and an institutional work lens, we aim at analysing of how club sport uses institutional work to enable institutional resilience for responding to the challenges of the COVID-19 pandemic. Thus, we show, which actors of club sport (who?) use which institutional work activities (how?) for enabling institutional resilience in the face of the pandemic’s challenges (why?). Results indicate that institutional resilience of club sport in the COVID-19 pandemic had an emergent and dynamic nature with an iterative passing through the phases of resilience. Sport clubs were the lead agents, but also unions and associations as non-profit-organisations applied manifold cultural, technical, and political work activities. Beyond the refinement of institutional work activities for club sport, we identified COVID-19 pandemic specific activities. These are visioning as a new cultural activity and reinterpreting (transforming) core operations for the digital space and legal networking as new technical institutional work activities. Hence, the novelty of the paper consists in advancing the conceptualisation of institutional resilience by illustrating the nature of institutional resilience (its characteristics) and by depicting institutional resilience as an outcome of institutional work.

Emotion Recognition Based on a EEG-fNIRS Hybrid Brain Network in the Source Space.

Background/Objectives: Studies have shown that emotion recognition based on electroencephalogram (EEG) and functional near-infrared spectroscopy (fNIRS) multimodal physiological signals exhibits superior performance compared to that of unimodal approaches. Nonetheless, there remains a paucity of in-depth investigations analyzing the inherent relationship between EEG and fNIRS and constructing brain networks to improve the performance of emotion recognition. Methods: In this study, we introduce an innovative method to construct hybrid brain networks in the source space based on simultaneous EEG-fNIRS signals for emotion recognition. Specifically, we perform source localization on EEG signals to derive the EEG source signals. Subsequently, causal brain networks are established in the source space by analyzing the Granger causality between the EEG source signals, while coupled brain networks in the source space are formed by assessing the coupling strength between the EEG source signals and the fNIRS signals. The resultant causal brain networks and coupled brain networks are integrated to create hybrid brain networks in the source space, which serve as features for emotion recognition. Results: The effectiveness of our proposed method is validated on multiple emotion datasets. The experimental results indicate that the recognition performance of our approach significantly surpasses that of the baseline method. Conclusions: This work offers a novel perspective on the fusion of EEG and fNIRS signals in an emotion-evoked experimental paradigm and provides a feasible solution for enhancing emotion recognition performance.

(Invited) Development of High-Bandwidth GaN-Based Micro-LEDs for Visible Light Communication

With the expectation of extremely high-capacity requirement of 6G networks, visible light communication (VLC) has abundant frequency resource and excellent performance in 6G integrated communication in space, air, underwater, indoor, and car networks [1]. The micro light emitting diode (micro-LED) is regarded as a reliable light source for high-speed VLC and is capable of illumination while providing communication. Compared to the traditional light source, micro-LED possesses better characteristics such as high bandwidth, low power consumption, long lifetime and high reliability [2-3].In this work, we made improvements in the micro-LED fabrication compared with the common negative doped GaN (common-n) devices we produced by shallow etching before [4]. Micro-LEDs can be manufactured into completely separate pixels for independent control by deep etching. For green micro-LEDs with a wavelength of 510nm, the light output power of deep etching one increased. At the same working current density, the -3dB bandwidth of deep etching micro-LED has an average growth of 50% compared to shallow etching one. Benefit from the promotion of optical power and -3dB bandwidth, micro-LED with independent etching structure have a better performance in VLC system. A record date rate of 6.58Gpbs was achieved by single green micro-LED employing the orthogonal frequency division multiplexing (OFDM) modulation scheme, which proposes a feasible optimization direction for the integration of micro-LED high-speed VLC and lighting. REFERENCES: [1] Chi N, Zhou Y, Wei Y, et al. Visible light communication in 6G: Advances, challenges, and prospects[J]. IEEE Vehicular Technology Magazine, 2020, 15(4): 93-102.[2] James Singh K, Huang Y M, Ahmed T, et al. Micro-LED as a promising candidate for high-speed visible light communication[J]. Applied Sciences, 2020, 10(20): 7384.[3] Lin R, Jin Z, Qiu P, et al. High bandwidth series-biased green micro-LED array toward 6 Gbps visible light communication[J]. Optics Letters, 2022, 47(13): 3343-3346.[4] Zhu S, Qiu P, Shan X, et al. Micro-LED based double-sided emission display and cross-medium communication[J]. IEEE Photonics Journal, 2022, 14(3): 1-5. Figure 1

Architectural spatial distribution and network connectivity characteristics of ancient military towns in Southwest China: a case study of Qingyan Ancient Town in Guiyang

Due multiple influences, such as Tusi, Tunpu, and minority culture, Tunpu military towns in Southwest China have unique historical and cultural heritage. At present, the ancient Tunpu military towns are not widely known internationally. In order to understand the layout characteristics of Tunpu military buildings in southwest China since the Ming Dynasty, the spatial distribution and military attributes of Qingyan Ancient Town, a typical military town of Tunpu culture, are studied by using Thiessen polygons, fractal theories, and complex network methods. The findings indicate that architectural spaces in the six districts have high spatial self-similarity and low spatial complexity and are distributed in clusters primarily impacted by natural factors and supplemented by humanistic factors. The architectural space networks of the six districts have high stability, low vulnerability, poor balance, and high connectivity. They reflect its interior architectural layout, which is based on close cooperation between villagers and military, taking into account trade and cultural life. Differences in the functionality of buildings lead to differences in the connectivity of the spatial network of buildings; the hierarchical, graded, and differentiated characteristics of architectural spatial network connectivity are influenced by both nature and society. Non-military functions all serve or are subordinate to military functions. The spatial network connectivity of traditional settlement architecture reflects the interaction between nature and society. By studying a Tunpu military ancient town in the southwest, we can better understand the historical military activities, cultural connotations, social changes, and historical background of traditional settlements. The historical planning of the defence of traditional settlements both contributes to its cultural heritage and as an important reference and inspiration for modern planning and management.

Nonlinear model predictive controller of hydrogenation of dimethyl oxalate for ethylene glycol production

Abstract Ethylene glycol (EG) is a valuable commodity organic intermediate that is produced using the catalyzed gas-phase hydrogenation process of dimethyl oxalate (DMO) from syngas. The reactor process is challenging to control because of its nonlinearity and multivariable condition. Thus, this study proposes the application of Neural Wiener model predictive control (NWMPC) for DMO hydrogenation reactor control. The application of empirical-based MPC, such as NWMPC, is still new in DMO hydrogenation reactor control. In order to simulate the process, the DMO hydrogenation reactor is modeled using Aspen Plus and Aspen Dynamic software. The Neural Wiener (NW) model is developed based on state space and neural network modeling using a Linear-Nonlinear (L-N) identification approach. A validation test is also performed to verify the accuracy of the NW model. Based on the test, the model accuracy is acceptable with the coefficient of determination (R2) of 0.965 for EG output mole fraction (first output) and R2 of 0.936 for product temperature (second output). The NWMPC capability is evaluated with a PID controller to handle a setpoint change in EG output mole fraction and reject disturbance in the feed stream flow rate. The control performance results have demonstrated the superior ability of the NWMPC to handle such scenarios better than PID in terms of controller action speed and profile.