Space Systems Research Articles

Design Process of a Memorial Square to Thank and Respect for Healthcare Workers after Covid-19 Pandemic

Open and green spaces are essential elements of cities. With the COVID epidemic, the importance of the need for open and green spaces in urban areas has become more understood. The aim of this study is to create a new and contemporary square in the working area where the current use and traffic create chaos, to add a new square to the open and green areas in Ankara (Turkey) and to create a connection between this area and the existing open and green areas. At the same time, health workers are honoured through a memorial area integrated into the square. The importance of the location chosen as the study area is that it is surrounded by many public health facilities and is a point of intersection of Ankara's existing open green space systems. Throughout the three-stage design process, brainstorming sessions were held, drawings and sketches were made, and urban analyses were carried out on transport, culture, art, education, health, open and green spaces. Solutions were proposed for both indoor and outdoor spaces, and the forms were transformed into functional design elements and reflected in the space. As a result, after the pandemic, a city square has been created where people can socialise again, with a monument, a square, water surfaces, an amphitheatre, viewing terraces, a market area, a bridge, sitting and walking areas that are appropriate to the capital.

Assessment of the physical and psychological aspects of the current life support system on the International Space Station for sustainable space exploration

Life support systems in space have been developed to recover a certain amount of oxygen and water. However, we still rely on resupplies for gas tanks, water bags, and food. To achieve sustainable human space exploration, we must also consider the astronauts’ wellbeing. This research analyzes and assesses the status of essential life support elements, which are air, water, and food, as well as wellbeing elements, including clothing, hygiene, and healthcare, on the International Space Station. The types and quantities of resupplies for each element were estimated by synthesizing data from multiple sources and compared against baseline values established by the National Aeronautics and Space Administration (NASA) for one crew member per day. To evaluate the qualitative and psychological dimensions of dependence on resupply missions, astronaut feedback and comments documented in reports and articles from space agencies were also analyzed as important references. The results show that resupplies involve not only gas tanks and water bags but also a significant number of spare items to maintain recovery systems. Food completely relies on resupplies, and regarding wellbeing elements, although the mass supplied from Earth seems to meet the space agency’s requirements, astronauts feel uncomfortable wearing the same clothes and using the same towels for days, especially exercise clothes, which can develop odors. It was also discovered that each resupply mission is inefficient as resupplies account for only 0.21% of the total launch mass. Relying on resupply missions has been associated with negative effects on both physical and psychological aspects, such as anxiety about the risk of running out of life support consumables, issues with stowage and odors caused by waste, and stress due to complicated cargo unloading and loading transfer operations. As humans explore the Moon and beyond, frequent resupplies will become impractical due to higher launch costs and longer delivery times, and suggestions for developing technologies to realize a sustainable human presence in space are being proposed.

On time-splitting methods for gradient flows with two dissipation mechanisms

We consider generalized gradient systems in Banach spaces whose evolutions are generated by the interplay between an energy functional and a dissipation potential. We focus on the case in which the dual dissipation potential is given by a sum of two functionals and show that solutions of the associated gradient-flow evolution equation with combined dissipation can be constructed by a split-step method, i.e. by solving alternately the gradient systems featuring only one of the dissipation potentials and concatenating the corresponding trajectories. Thereby the construction of solutions is provided either by semiflows, on the time-continuous level, or by using Alternating Minimizing Movements in the time-discrete setting. In both cases the convergence analysis relies on the energy-dissipation principle for gradient systems.

Error bounds of Approximate Weak Rescaled Pure Greedy Algorithms

We study the greedy algorithms for [Formula: see text]-term approximation. We propose a modification of the Weak Rescaled Pure Greedy Algorithm (WRPGA) — Approximate Weak Rescaled Pure Greedy Algorithm (AWRPGA) — with respect to a dictionary of a Banach space [Formula: see text]. By using a geometric property of the unit sphere of [Formula: see text], we obtain a general error estimate in terms of some [Formula: see text]-functional. This estimate implies the convergence condition and convergence rate of the AWRPGA. Furthermore, we obtain the corresponding error estimate for the Vector Approximate Weak Rescaled Pure Greedy Algorithm (VAWRPGA). We show that the AWRPGA (VAWRPGA) performs as well as the WRPGA (VWRPGA) when the noise amplitude changes relatively little. Finally, by using the wavelet bases and trigonometric system of Lebesgue spaces, we show that the convergence rate of the AWRPGA is optimal.

Analyzing numerical simulation of ventilation system and filter membrane: The exposure of airborne nanoparticles in health interior Space

Improving air quality in indoor areas or interior spaces is a vital need. High PM 2.5 concentration or excessive air pollution causes severe damage to human health and the respiratory system. Air ventilation systems in health spaces are more necessary as there is a higher human crowd flow in viral-susceptible areas. The recent COVID situation has made us rethink the re-arrangement of hospitals' interior space and air ventilation systems. For that reason, improving high-efficiency particulate air filters is the need of the hour. The main objective of this research is the optimization and redesign of the air filtration system in health centers by integrating a hybrid combination system of HEPA filters based on computer modeling and numerical simulation. To analyze the effectiveness of the hybrid system, first, we simulated the existing air filtration system by using a successful and proven air filtering computational model in COMSOL Multiphysics. After that, we generated comparative numerical results and graphical analysis obtained by COMSOL to demonstrate the competency of the hybrid system over the conventional air filtration system. Finally, we have shown the most optimum and effective way to implement the hybrid system in health centers by analyzing the Computational Fluid Dynamics of different types of opening and ventilation systems. This research will play an essential role in future interior air quality improvement and effective anti-viral design of health spaces.

Carbon Neutrality Benefit by Developing Underground Space and Overlying Green Land: Calculation Methodology and Case Study

The advancement of ecological civilization has heightened the urgency for urban emission reductions. Currently, there is a significant gap in the quantitative assessment of the carbon neutrality benefit of developing underground space and overlaying urban green land. To address this, this study presents a carbon neutrality benefit assessment model based on building lifecycle theory. The model quantifies the carbon emissions of typical public buildings utilizing aboveground/underground space and assesses the carbon sink impacts of green lands. Notably, it introduces the innovative parameter of characteristic time to evaluate how the comprehensive development of underground space and aboveground urban green land contributes to achieving carbon neutrality. Case analysis of a typical shopping mall in northern China revealed that, in comparison to aboveground buildings, underground buildings exhibit higher energy consumption for construction and lighting; however, they demonstrate superior thermal performance, providing warmth in winter and coolness in summer. Furthermore, urban green spaces of equivalent building area can sequester a portion of the carbon emissions produced by underground buildings, resulting in a lower overall carbon emission profile for the underground space system throughout its lifecycle compared to that of the aboveground space system. Consequently, the development of underground spaces plays a crucial role in advancing carbon neutral objectives. The study also emphasizes the importance of selecting plant communities with enhanced carbon sequestration capacities and developing corresponding green spaces to better meet carbon neutrality objectives. This research offers a novel perspective for evaluating the carbon neutrality benefits of underground space systems, providing valuable design guidance for integrating urban underground and aboveground spaces.

Design study of a camera system for Earth observation as a payload on the small satellite ROMEO

AbstractThe importance of a safe food supply has increased due to climate change and its consequences. The number and severity of floods, droughts and plant diseases are rising which causes massive crop failures. Early and precise detection of plant diseases can lower crop failures as it enables early containment. Moreover, it promotes the targeted use of pesticides to protect the biodiversity. Satellite sensors improve the detection of plant diseases by enabling frequent and extensive vegetation observation. Hence, we present the design of a camera system for Earth observation on small satellites with a focus on the detection of plant diseases. The disease detection of sugar beets was chosen as the primary objective due to their importance for the German agriculture. This work is divided into two parts. First, the spectra of sugar beets are analyzed to determine spectral channels for a camera system. Second, a camera system is defined to capture spectral information within the previously defined wavelength ranges. The spectra of healthy and diseased sugar beets were measured in fields for agricultural research in Central Germany using a portable spectroradiometer. The investigated diseases are Cercospora leaf spot and virus yellows, which are among the most important pathogens worldwide. Based on the measured data, the so-called Normalized Difference Sugar Beet Index (NDSBI) is defined, which is a custom index to detect these diseases. We can prove that this index enables more precise detection of these sugar beet diseases than existing indices like the Normalized Difference Vegetation Index (NDVI). The camera system is designed as a payload for the small satellite Research and Observation in Medium Earth Orbit (ROMEO), which is being developed at the University of Stuttgart’s (US) Institute of Space Systems (IRS). The proposed design fulfills the high radiation requirements as well as the system constraints of mass and volume. Three different options for the camera system are developed: two designs for the development at the US, one with lens optics and one with mirror optics, and an adjusted commercial camera system. All defined camera systems permit the measurement of the NDSBI to precisely detect sugar beet diseases.

Disorder-induced phase transitions in a two-dimensional magnetic topological insulator system

We investigate the phase diagram of a two-dimensional magnetic topological system in the parameter space of uncorrelated Anderson disorder and Zeeman splitting energy. In the absence of disorder, the system undergoes the phases of higher-order topological insulators (HOTIs), Chern insulators (CIs) with Chern numbersC = 2 andC = 1, and band insulators successively with enhancing Zeeman energy. The phase boundary separating these phases is found to be strongly deformed by the disorder, which leads to several topological Anderson insulators. Specifically, there exist phase transitions between CI withC = 2 and HOTI, and between CIs withC = 1 andC = 2. For the former one, it is in fact a phase transition between first-order and second-order topological phases. Besides, these disorder induced phase transitions are well explained by self-consistent Born approximation.

Variational principles of physics and the infinite Ramsey theory

Abstract Application of the Ramsey Infinite Theorem to the fundamental variational principles of physics is addressed. The Hamilton Least Action Principle states that, for a true/actual trajectory of a system, Hamilton’s Action is stationary for the paths, which evolve from the preset initial space-time point to the preset final space-time point. The Hamilton Principle distinguishes between the actual and trial/test trajectories of the system in the configurational space. This enables the transformation of the infinite set of points of the configurational space (available for the system) into the bi-colored, infinite, complete, graph, when the points of the configurational space are seen as the vertices, actual paths connecting the vertices/ points of the configurational space are colored with red; whereas, the trial links/paths are colored with green. Following the Ramsey Infinite Theorem, there exists the infinite, monochromatic sequence of the pathways/clique, which is completely made up of actual or virtual paths, linking the interim states of the system. The same procedure is applicable to the Maupertuis’s principle (classical and quantum), Hilbert-Einstein relativistic variational principle and reciprocal variational principles. Exemplifications of the Infinite Ramsey Theorem are addressed.

Alinhamento do Programa Estratégico de Sistemas Espaciais (PESE) à Estratégia Nacional de Defesa (END)

This research had as objective analyzing to what extent the Strategic Program of Space Systems (PESE) influences the fulfillment of the strategic objective defined as the priority of aerial surveillance, established for the Brazilian Air Force (FAB) in the National Defense Strategy (END). Due to the characteristics of both documents, the theoretical basis was mainly based on the principles of strategic planning. The Value Focused Thinking (VFT) theory and the techniques of the content analysis provided support for data collection and structuring. Initially, the methodology consisted of a documentary research in order to define the concept of aerial surveillance. Subsequently, a hierarchy of objectives was constructed, composed of the strategic objective of the END and intermediate objectives. The measurement of the contribution of the PESE to the accomplishment of the intermediate objectives was obtained applying the principles of the VFT. Finally, these measures were integrated in order to identify the contribution of the PESE to the strategic objective of the END, resulting in a value index of 0.567. The data were interpreted and analyzed in light of the principles of strategic planning and it was concluded that the main contributions of the PESE are related to the strengthening of the national industry, the monitoring of areas of interest from space and the network operation between the Armed Forces (FA). On the other hand, the PESE contributes little to the issues related to obtaining access to space and the integration of space activities into FAB operations, through the Brazilian Aerospace Defense System (SISDABRA).

Dynamically scaled equivalent modelling for flexible multibody systems in space

Dynamically scaled equivalent modelling for flexible multibody systems in space

Global well-posedness and large-time behavior for a special 21 2D full compressible viscous non-resistive MHD system

In this paper, we consider the full compressible, viscous, non-resistive MHD system under the assumption that the fluids move on a plane while the magnetic field is oriented vertically. Within the framework of Besov spaces, by introducing several new unknown quantities and exploiting the intrinsic structure of the system, we prove the global well-posedness of strong solutions for initial data close to a constant equilibrium state. Furthermore, under some suitable additional conditions involving only the low-frequency part of the initial perturbation, we develop a Lyapunov-type energy argument, which yields the optimal time-decay rates of the global solution. To the best of our knowledge, our result is the first one on global-in-time solvability to the full compressible, viscous, non-resistive MHD system in multi-dimensional whole space.

Digital Characteristics of Spatial Layout in Urban Park Scene Space: Spatial Classification, Quantitative Indicators, and Design Applications Based on Completed Park Cases

Urban parks are important components of the urban green space system, providing residents with a variety of leisure options. The design’s focal point is the spatial layout of the different use scenarios within these parks. Previous studies have largely concentrated on the scene and macro layout of urban public spaces but have not thoroughly investigated the digital characteristics and corresponding parametric methods for the layout of different internal use scenes in urban green spaces. This research selected 18 urban parks from various global regions as case samples and categorized eight typical park scene space types based on common activity scene requirements in park design using AutoCAD to identify vector boundaries in each sample. To examine the digital characteristics of these scene space types, a quantitative index system was established, including spatial density and scale indicators, spatial connection relationship indicators, and spatial unit morphology indicators. The analysis of these indicators across the samples shows that the number of scene spaces is positively correlated with the total park area, while natural experience scenes constitute the largest proportion of urban parks. Different scene types exhibit distinct spatial layouts; for example, circulation spaces demonstrate high connectivity due to their role in directing visitor flow. Some spaces exhibit a more fixed scale and size, while others vary considerably. Finally, this research develops a parametric design framework using the Grasshopper platform. By taking a park in Nanjing as a case study, this paper illustrates how to utilize digital layout features to generate scene space layouts, offering insights into intelligent generative design. This approach provides a structured method to enhance urban park design through the application of digital and parametric tools, contributing to the broader field of urban park design.

Well-posedness and stability for Boussinesq systems in weak-Lorentz spaces with Muckenhoupt weights

We investigate the existence and stability of mild solutions of Boussinesq system in the weak-Lorentz spaces with Muckenhoupt weight in the framework of half-spaces. Our strategy starts with the corresponding linear system, for which we combine the weighted L p − L q -smoothing estimates and interpolation functors to prove Yamazaki-type inequality and establish the existence of the bounded mild solutions on the half-line R + . Then we use the results of linear systems and fixed point arguments to establish the existence, uniqueness and stability of the mild solutions to the Boussinesq systems.

Differential systems in Sobolev spaces with generic inhomogeneous boundary conditions

The paper contains a review of results on linear systems of ordinary differential equations of an arbitrary order on a finite interval with the most general inhomogeneous boundary conditions in Sobolev spaces. The character of the solvability of such problems is investigated, their Fredholm properties are established, and their indexes and the dimensions of their kernels and co-kernels are found. In addition, necessary and sufficient conditions of continuity in the parameter of the solutions of the introduced classes of boundary-value problems in Sobolev spaces of an arbitrary order are obtained.

On the acceptable level of risks in the implementation of strategic planning programs for technological innovations in the development of space systems

It is shown that owing to the available incompleteness or inaccuracy of information on the conditions of implementing programs of strategic planning of technological innovations, there is a risk. Management of implementation of the programs is, in fact, management of its risks. A method of determining the admissible level of risk of implementing the programs of space technology development that represents the guaranteed level of the project wastelessness is proposed and can be considered as the criterion of the necessity to take measures to decrease the risks of technological innovations, as well as the criterion of the expediency of continuing (terminating) implementation of the program or its separate components. Calculations of admissible risk level in relation to federal programs of the development of space equipment are given.

Assessing the Impact of Observations on the Brazilian Global Atmospheric Model (BAM) Using Gridpoint Statistical Interpolation (GSI) System

This article describes the main features of the impacts of global observations on the reduction of errors in the data assimilation (DA) cycle carried out in the Brazilian Global Atmospheric Model (BAM) at Center for Weather Forecast and Climate Studies [Centro de Previsão de Tempo e Estudos Climáticos (CPTEC)] at the Brazilian National Institute for Space Research [Instituto Nacional de Pesquisas Espaciais (INPE)]. These results show the importance of studying and evaluating the contribution of each observation to the DA system, therefore, two experiments (exp1/exp2) were performed with different configurations of the BAM model, with exp2 presenting the best fit between the Gridpoint Statistical Interpolation (GSI) and BAM systems. The BAM model was validated by the statistical metrics of root mean-square error and correlation anomaly, but this validation is not explored in this paper. A metric was applied that does not depend on the adjoint-based method, but only on the residuals that are made available in the GSI system for the observation space, given by the total impact, the fractional impact and the fractional beneficial impact. In general, the average daily showed that the observations of the global system that contribute most to the reduction of errors in the DA cycle are from the pilot balloon data (−3.54/−3.45 J kg−1)and the profilers (−2.13/−1.97 J kg−1), and the smallest contributions came from the land (−0.28/−0.29 J kg−1) and sea (−0.44/−0.44 J kg−1) surfaces. The same pattern was observed for the synoptic times presented. However, when verifying the fraction of the impact by each type of observation, it was found that the radiance data (64.88/30.30%), followed by radiosondes (14.85/27.42%) and satellite winds (11.03/22.70%), are the most important fractions for both experiments. These results show that the DA system is working to generate the best analyses at the research center and that the deficiencies found in some observations can be adjusted to improve the development of the GSI and the BAM model, since together, the entire database used is evaluated, as well as the forecast model itself, indicating the relationship between the assertiveness of the atmospheric model and the DA system used at the research center.

CONCERNING ONE SUPPLEMENT TO UNIFICATION METHOD OF N.N. KRASOVSKII IN DIFFERENTIAL GAMES THEORY

The paper deals with the game problem of approach for a conflict-controlled system in a finite-dimensional Euclidean space at a fixed moment of time. The problem of approximate calculation of the solvability sets is studied for the considered approach game. An approach is proposed for approximate calculation of solvability sets on the basis of a unification model, which supplements the unification method of N.N. Krasovskii in the theory of differential games.

HE CAUCHY PROBLEM FOR PARABOLIC SYSTEM WITH VARIABLE COEFFICIENTS IN ANISOTROPIC ZYGMUND SPACES

The Cauchy problem for a second-order parabolic system with coefficients and the right hand side which belong to the Zygmund anisotropic space is considered. A smoothness scale of the Cauchy problem solutions in anisotropic Zygmund spaces is obtained. A priori estimates of solutions for uniformly elliptic systems in isotropic Zygmund spaces are derived.

Post-Earthquake Urban Planning in Türkiye: Evaluating Disaster Refuge Systems in Hatay and Istanbul

Countries prone to significant earthquakes often develop disaster refuge and relief urban park systems to enhance urban open green spaces, which serve as temporary shelters for evacuation after seismic events. This paper examines the disaster refuge sites and urban open green space system in the center of Hatay following the February 6, 2023 earthquake. The findings provide insights into the resilience of Turkish cities after seismic events. Subsequently, the refuge sites and green space systems in Istanbul, a metropolis expected to experience a major earthquake, were analyzed in light of the Hatay example. Using ArcGIS, the service areas of shelter sites and urban open green spaces (within a 15-minute walking distance) were calculated and compared. Results indicate that the service areas for emergency shelters in the center of Hatay and Istanbul's Fatih district are insufficient. This highlights the need for better-planned urban open green spaces for evacuation purposes. This study makes significant contributions to improving shelter and evacuation processes after earthquakes in the fields of disaster management and urban planning.