Large Squares Research Articles

A residual-based surrogate hyperplane extended Kaczmarz algorithm for large least squares problems

A residual-based surrogate hyperplane extended Kaczmarz algorithm for large least squares problems

Physiological and immunological assessment of two types of crayfish in aquaculture

Due to the need to develop domestic aquaculture of decapod crustaceans, one of the urgent issues is monitoring the health of these aquatic organisms through the most informative bioindicators — hemolymph indicators. The aim of the study was a comparative physiological and immunological assessment of long-toed (Pontastacus leptodactylus) and Australian red-clawed (Cherax quadricarinatus) river crayfish contained in a closed water use facility. The main hydrochemical parameters generally met the existing requirements. The physiological and immunological condition of crayfish was assessed by hematological and cytochemical analyses. Hemolymph samples were taken in vivo by puncture of the ventral sinus. The total number of hemocytes was determined in the native hemolymph in the Goryaev chamber. The number of cells in five large squares was counted. Lysosomal cationic protein was detected in hemocytes by the cytochemical reaction with bromophenol blue, which we previously modified. Red-clawed crayfish have a significantly 45% higher total number of hemocytes, which indicates its greater immune resistance to pathogens compared with long-toed crayfish. The most significant species differences in the hemogram were noted for agranulocytes (HC I) — in long-fingered crayfish, the indicator is higher with a high confidence coefficient (t). With a high degree of confidence, it is possible to judge a higher proportion of semigranulocytes (HC II) in red-lobed crayfish. The proportion of HC IV of long-fingered crayfish is greater than that of red-clawed crayfish. In red-clawed crayfish, the average cytochemical coefficient of ACC is lower than in long-fingered crayfish. This also confirms its high immune resistance due to the consumption of highly cytotoxic cationic protein in the process of immune protection.

Photocatalytic activity and mechanism of YMnO3/NiO photocatalyst for the degradation of oil and gas field wastewater.

One-step hydrothermal method has been used to synthesize YMnO3@NiO (YMO@NO) photocatalysts with high photocatalytic activity for the degradation of oil and gas field wastewater under simulated solar irradiation. Through various characterization methods, it has been confirmed that the YMO@NO photocatalyst comprises only YMO and NO, without any other impurities. The microstructure characterization confirmed that the YMO@NO photocatalyst was composed of large squares and fine particles, and heterojunction was formed at the interface of YMO and NO. The optical properties confirm that the YMO@NO photocatalyst has high UV-vis optical absorption coefficient, suggesting that it has high UV-vis photocatalytic activity. Taking oil and gas field wastewater as degradation object, YMO@NO photocatalyst showed the highest photocatalytic activity (98%) when the catalyst content was 1.5g/L, the mass percentage of NO was 3%, and the irradiation time was 60min. Capture and stability experiments confirm that the YMO@NO photocatalyst is recyclable and electrons, holes, hydroxyl radicals and superoxide radicals play major roles in the photocatalysis process. Based on experiments and theoretical calculations, a reasonable photocatalytic mechanism of the YMO@NO photocatalyst is proposed.

Randomized symmetric Gauss-Seidel method for solving linear least squares problems

<abstract><p>We introduced a random symmetric Gauss-Seidel (RSGS) method, which was designed to handle large scale linear least squares problems involving tall coefficient matrices. This RSGS method projected the approximate residual onto the subspace spanned by two symmetric columns at each iteration. These columns were sampled from the coefficient matrix based on an effective probability criterion. Our theoretical analysis indicated that RSGS converged when the coefficient matrix had full column rank. Furthermore, numerical experiments demonstrated that RSGS outperformed the baseline algorithms in terms of iteration steps and CPU time.</p></abstract>

Building a “reservoir of social resilience:” A strategy for social infrastructure regeneration in shrinking cities based on social network analysis

Northeast China is generally experiencing a shrinkage phenomenon similar to that in other old industrial regions worldwide. Large-scale growth-oriented regeneration programs by the government over the long term have led to the decline of social infrastructure in inner cities, thereby causing a structural crisis at the social level, and exacerbating the negative effects of shrinkage. This study investigated Hegang as a typical shrinking city in northeastern China. Coupling analysis was conducted based on network indexes and two categories of social resilience indexes to identify the key social infrastructure that provides residents with resilience to help cope with shrinkage. Our results demonstrate the centralizing effect of large-scale retail sites, and large green spaces and squares on social resilience. We also found that these categories of social infrastructure had effects across different areas of the city, which then provided social resilience to a wider range of residents. Our results also provide evidence for inequalities in the ability of residents to cope with shrinkage. Based on these findings, we characterize China's urban shrinkage and future development trends, and discuss the limitations of the regeneration model that has long been adopted by local governments. We suggest that local governments should consider incorporating investment in resilience to shrinkage into regeneration policies. They should also consider regenerating social infrastructure and deploying funds to a holistic network to build “reservoirs” of social resilience in shrinking cities. In addition, we highlight our methodological contributions and argue that social resilience monitoring should be integrated into China's urban physical examination framework to enhance dynamic planning and the sustainable regeneration capacity of shrinking urban local governments.

Approximating sparse Hessian matrices using large-scale linear least squares

Large-scale optimization algorithms frequently require sparse Hessian matrices that are not readily available. Existing methods for approximating large sparse Hessian matrices have limitations. To try and overcome these, we propose a novel approach that reformulates the problem as the solution of a large linear least squares problem. The least squares problem is sparse but can include a number of rows that contain significantly more entries than other rows and are regarded as dense. We exploit recent work on solving such problems using either the normal equations or an augmented system to derive a robust approach for computing approximate sparse Hessian matrices. Example sparse Hessians from the CUTEst test problem collection for optimization illustrate the effectiveness and robustness of the new method.

How Could Increasing Temperature Scenarios Alter the Risk of Terrorist Acts in Different Historical Squares? A Simulation-Based Approach in Typological Italian Squares

Squares in the urban historical built environment are public open spaces prone to the risk of terrorist acts, essentially because they are ideal soft targets and attract significant user densities. Risk assessment methods should consider how users behave in them, both before and during an accident (i.e., the evacuation process). In addition to squares’ morphology and layout, and considering that urban areas are more and more prone to the effects of increasing temperatures, outdoor climate conditions can alter the initial scenario. In fact, such conditions can lead users to gather in specific outdoor areas, where they can look for shadows and shelter. This work hence proposes a simulation-based approach to assess how differences in users’ behaviours in response to increasing temperatures and squares’ morphology can alter the risk of terrorist acts in an emergency evacuation. An agent-based model is developed to simulate the interactions between users, hazards and the historical built environment. The work considers four typological squares prone to terrorist acts since they host a special building attracting users in front of it. These squares are derived from the analysis of Italian historical contexts within the BE S2ECURe project. Users are generated in the public open space (thus, before the terrorist act) depending on the intended uses of the square and on the outdoor temperature, which is affected by the square’s morphology. Three different users’ behaviours are modelled to consider (or not) the effects of the outdoor temperature on users’ thermal acceptability levels in an increasing temperature situation. Then, two evacuation scenarios are simulated: (a) a general evacuation process, without attackers, as the baseline for the risk assessment; and (b) an armed assault with cold weapons, to define one of the most probable attack situations in open spaces. Evacuation performance indicators are developed to assess users’ risk. Preliminary verifications demonstrate the capabilities of the approach. The results show that higher differences in evacuation indicators are noticed in large and asymmetric squares, since their conditions highly affect the variability of users’ behaviours in response to increasing temperatures. At the same time, stronger safety behaviours in response to increasing temperatures could reduce emergency issues because they allow users to be more dispersed and initially placed farther from the attack area. Decision-makers could take advantage of the proposed approach and simulation tool, moving towards an effectiveness analysis of solutions to increase the thermal comfort of users in respect of the risk levels during an evacuation. Finally, applications to real-world scenarios are thus encouraged to compare such idealized results with effective conditions.

Building Shanghai in the borderlands: a visual approach to the restructuring of the Uyghur City in Xinjiang

Buildings and material infrastructure in cities are not just there; rather, they are embedded in complex political and social planning and construction contexts. In China, spatial transformations and urbanisation in its eastern and coastal regions have received a great deal of attention. This article investigates the relatively little explored urban development in China’s Northwestern Uyghur homeland of XUAR (Xinjiang Uyghur Autonomous Region). Based on 12 months of ethnographic fieldwork between 2010 and 2017, the article outlines the ways in which Sinicization, modernisation and globalisation have simultaneously changed the morphology of XUAR’s cities. The restructuring of material urban infrastructure has also challenged local ethnic place-making. Until the opening-up reforms in the 1980s, Uyghur ethnic belonging used to manifest visually in urban spaces through mosques, Muslim cemeteries or low-rise mud-brick buildings. In recent decades, such structures have been gradually demolished and replaced with Chinese-style urban landscapes such as high-rise residential compounds, riverside promenades or large central squares. This leaves a void for ethnic self-identification through forms of the built environment. Uyghur urban middle-class citizens critically engage with urban restructuring in their native places. The article highlights the ways in which they negotiate ethnicity, social status or the relation to the state through reflecting on the construction and perception of architecture.

Методика подсчета общего числа гемоцитов австралийского красноклешневого рака

The optimal formula for calculating the total number of hemocytes (HTN) of the Australian red-claw crayfish (Cherax quadricarinatus) has been established, which allows optimizing the time of counting HTN without re-ducing accuracy. Methodical recommendations on preparing a hemolymph sample, HTN calculation and differentiated calculation of hemocytes are given. It was found out that the differences in HTN are minimal when using different formulas, which is con-firmed by the analysis of variance F = 0.011, p = 0.998, the average values of HTN range from 2 384 to 2 427 cell/µl. Conducting multiple comparisons also demonstrated that the differences between the formulas are minimal: the significance levels between the formulas were p = 0.99. The optimal formula for the Australian red-claw crayfish is: HTN in 1 µl = N • 10, where N is the total number of hemocytes in 25 large squares of Gorjaev’s chamber. The counting chamber should be clean, since when even small dust particles are found on the grid, hemocyte clusters can form and impede counting, or the result of the calculation will be incorrect, because the distribution 
 of hemocytes on the grid will not be uniform. After filling the chamber with hemolymph, it is recommended to wait 
 1-1.5 minutes so that the movement of the hemolymph stops and the hemocytes stop moving. It is recommended to use an anticoagulant, which prevents the rapid decay of cells and promotes their uniform distribution on the grid of the chamber without developing clots (clusters) that affect the accuracy of counting. Working with the whole hemolymph implies the speed and accuracy of the researcher's actions, since it quickly coagulates and forms clusters of hemocytes. In order to avoid confusion when counting cells located on the border between squares, Egorov’s rule is applied. The optimal increase for counting is a 400-fold increase.

Self-assembly of dodecagonal and octagonal quasicrystals in hard spheres on a plane.

Hard spheres are one of the most fundamental model systems in soft matter physics, and have been instrumental in shedding light on nearly every aspect of classical condensed matter. Here, we add one more important phase to the list that hard spheres form: quasicrystals. Specifically, we use simulations to show that an extremely simple, purely entropic model system, consisting of two sizes of hard spheres resting on a flat plane, can spontaneously self-assemble into two distinct random-tiling quasicrystal phases. The first quasicrystal is a dodecagonal square-triangle tiling, commonly observed in a large variety of colloidal systems. The second quasicrystal has, to our knowledge, never been observed in either experiments or simulations. It exhibits octagonal symmetry, and consists of three types of tiles: triangles, small squares, and large squares, whose relative concentration can be continuously varied by tuning the number of smaller spheres present in the system. The observed tile composition of the self-assembled quasicrystals agrees very well with the theoretical prediction we obtain by considering the four-dimensional (lifted) representation of the quasicrystal. Both quasicrystal phases form reliably and rapidly over a significant part of parameter space. Our results demonstrate that entropy combined with a set of geometrically compatible, densely packed tiles can be sufficient ingredients for the self-assembly of colloidal quasicrystals.

Cortical mechanisms of visual brightness.

SUMMARYThe primary visual cortex signals the onset of light and dark stimuli with ON and OFF cortical pathways. Here, we demonstrate that both pathways generate similar response increments to large homogeneous surfaces and their response average increases with surface brightness. We show that, in cat visual cortex, response dominance from ON or OFF pathways is bimodally distributed when stimuli are smaller than one receptive field center but unimodally distributed when they are larger. Moreover, whereas small bright stimuli drive opposite responses from ON and OFF pathways (increased versus suppressed activity), large bright surfaces drive similar response increments. We show that this size-brightness relation emerges because strong illumination increases the size of light surfaces in nature and both ON and OFF cortical neurons receive input from ON thalamic pathways. We conclude that visual scenes are perceived as brighter when the average response increments from ON and OFF cortical pathways become stronger.

Solving large linear least squares problems with linear equality constraints

We consider the problem of solving large-scale linear least squares problems that have one or more linear constraints that must be satisfied exactly. While some classical approaches are theoretically well founded, they can face difficulties when the matrix of constraints contains dense rows or if an algorithmic transformation used in the solution process results in a modified problem that is much denser than the original one. We propose modifications with an emphasis on requiring that the constraints be satisfied with a small residual. We examine combining the null-space method with our recently developed algorithm for computing a null-space basis matrix for a “wide” matrix. We further show that a direct elimination approach enhanced by careful pivoting can be effective in transforming the problem to an unconstrained sparse-dense least squares problem that can be solved with existing direct or iterative methods. We also present a number of solution variants that employ an augmented system formulation, which can be attractive for solving a sequence of related problems. Numerical experiments on problems coming from practical applications are used throughout to demonstrate the effectiveness of the different approaches.

Empirical Variational Mode Decomposition Based on Binary Tree Algorithm.

Aiming at non-stationary signals with complex components, the performance of a variational mode decomposition (VMD) algorithm is seriously affected by the key parameters such as the number of modes , the quadratic penalty parameter and the update step . In order to solve this problem, an adaptive empirical variational mode decomposition (EVMD) method based on a binary tree model is proposed in this paper, which can not only effectively solve the problem of VMD parameter selection, but also effectively reduce the computational complexity of searching the optimal VMD parameters using intelligent optimization algorithm. Firstly, the signal noise ratio (SNR) and refined composite multi-scale dispersion entropy (RCMDE) of the decomposed signal are calculated. The RCMDE is used as the setting basis of the , and the SNR is used as the parameter value of the . Then, the signal is decomposed into two components based on the binary tree mode. Before decomposing, the and need to be reset according to the SNR and MDE of the new signal. Finally, the cycle iteration termination condition composed of the least squares mutual information and reconstruction error of the components determines whether to continue the decomposition. The components with large least squares mutual information (LSMI) are combined, and the LSMI threshold is set as 0.8. The simulation and experimental results indicate that the proposed empirical VMD algorithm can decompose the non-stationary signals adaptively, with lower complexity, which is O(n2), good decomposition effect and strong robustness.

Signals from Single-Opponent Cortical Cells in the Human cVEP.

We used the chromatic visual evoked potential (cVEP) to study responses in human visual cortex evoked by equiluminant color stimuli for 6 male and 11 female observers. Large-area, colored squares were used to stimulate Single-Opponent cells preferentially, and fine color-checkerboard stimuli were used to activate Double-Opponent responses preferentially. Stimuli were modulated along the following two directions in color space: (1) the cardinal direction, L-M or M-L of DKL (Derrington, Krauskopf, and Lennie) space; and (2) the line from the white point to the color of the Red LED in the display screen, which was approximately intermediate between the L-M and -S directions in DKL space in cone-contrast coordinates. The amplitudes of cVEPs to large squares were smaller than those to checkerboards, and the latency of the cVEP response to squares was significantly less than the checkerboard latency. The latency of cVEP responses to the squares varied little with cone-contrast unlike the steep reduction of latency with cone-contrast observed in responses to color checkerboard patterns. The dynamic differences between cVEPs to squares and checkerboards support the hypothesis that a distinct neuronal mechanism responded to squares: Single-Opponent cells. Response amplitude, latency, and transientness-and their dependence on cone-contrast-were similar in the responses in the L-M and Red color directions. The similarity supports the hypothesis that the Single-Opponent signals in the cVEP come from a distinct population of cells that receives subtractive inputs from L and M cones, either L-M or M-L.SIGNIFICANCE STATEMENT This article is about characterizing the visual behavior of a distinct population of neurons in the human visual cortex, the Single-Opponent color cells. Based on single-cell results in the visual cortex of macaque monkeys, we used large uniformly colored stimuli to isolate the responses of Single-Opponent cells in the chromatic visual evoked potential (cVEP) recorded on the scalp of human observers. VEP signals recorded under conditions believed to reveal Single-Opponent responses are small and transient. Their time course is relatively unaffected by cone-contrast, and they are relatively insensitive to stimulus modulation of short wavelength-sensitive S cones. Because Single-Opponent cells convey signals that can be used to judge the color of scene illumination, knowing their visual properties is important for understanding color vision.

Градостроительная политика Испании в Новом Свете на примере Мехико, колониального мегаполиса страны

This article analyzes the history of the Mexico City, the capital of the vice-kingdom of New Spain since its foundation until the end of the colonial period. The author focuses on the main principles of urban pol-icy in the colonies, city plans, development and transformation of the city throughout the colonial history. Conquering the local population and moving across the territory of Mexico, the Spanish conquistadors not only conquered existing settlements, but also founded their own fortresses and outposts, attaching exceptional importance to the con-struction of cities on the territory of colonial possessions. New Spanish cities in America were used by the conquistadors as strongholds for fur-ther colonization and economic development of subordinate territories. The appearance of Spanish cities, their fortifications, Catholic churches were supposed to inspire the Indians with reverence and fear of the con-querors. The urbanization of the New World proceeded as an important link in the process of conquest and development of new territories by the Spanish conquistadors. The future metropolis of New Spain, Mexi-co City, was located on the site of the main Aztec city of Tenochtitlan. The idea to found a city on the site of the Indian Tenochtitlan belonged to E. Cortes. The plan of the city of Mexico belonged to the famous Spanish architect Garcia Bravo. By the beginning of the XIX century. Mexico City grew, expanded, the city had 335 streets, 146 lanes, 12 blocks, 90 large and small squares. The rapid development of the city of Mexico City was interrupted by the events of the War of Independ-ence, the destruction of which had to be liquidated in the first quarter of the 19th century.

Hitler’s Northern Utopia: Building the New Order in Occupied Norway

Hitler’s Northern Utopia: Building the New Order in Occupied Norway

A two-step randomized Gauss-Seidel method for solving large-scale linear least squares problems

<abstract><p>A two-step randomized Gauss-Seidel (TRGS) method is presented for large linear least squares problem with tall and narrow coefficient matrix. The TRGS method projects the approximate solution onto the solution space by given two random columns and is proved to be convergent when the coefficient matrix is of full rank. Several numerical examples show the effectiveness of the TRGS method among all methods compared.</p></abstract>

A new limited memory method for unconstrained nonlinear least squares

This paper suggests a new limited memory trust region algorithm for large unconstrained black box least squares problems, called LMLS. Main features of LMLS are a new non-monotone technique, a new adaptive radius strategy, a new Broyden-like algorithm based on the previous good points, and a heuristic estimation for the Jacobian matrix in a subspace with random basis indices. Our numerical results show that LMLS is robust and efficient, especially in comparison with solvers using traditional limited memory and standard quasi-Newton approximations.

THE EVOLUTION OF THE FORMATION OF THE ARCHITECTURE OF THE STUDIO OBJECTS

The article analyzes the development and influences on the formation of film studio architecture. The article reveals to what extent and how the architecture of film studios has changed and what influenced it. The work aims to study and analyze the development and factors of influence on the evolution of the architecture of film studios. The tasks include identifying the periods of formation of architecture, characterizing these periods, and investigating the factors influencing them. Among the main conclusions is that it is appropriate to focus on the third stage of development of the architecture of studio buildings. Each period has its peculiarity of architecture. I = 1 building 1 function, II = spaciousness, III = optimization, avoidance of large squares. From the early stages to the present day, technological factors have the greatest influence. Indeed, with the development of technology (the emergence of sound, colour, etc.), architecture became spatial (the number of necessary pavilions, workshops), and the development of computer technology and graphics led to the development of research without filming pavilions and workshops.

Urban Squares in Late Bronze Age Ugarit: a Street View on Ancient Near Eastern Governance

Urban Squares in Late Bronze Age Ugarit: a Street View on Ancient Near Eastern Governance