Simple Connection Research Articles

Topology of random -dimensional cubical complexes

Abstract We study a natural model of a random $2$ -dimensional cubical complex which is a subcomplex of an n-dimensional cube, and where every possible square $2$ -face is included independently with probability p. Our main result exhibits a sharp threshold $p=1/2$ for homology vanishing as $n \to \infty $ . This is a $2$ -dimensional analogue of the Burtin and Erdoős–Spencer theorems characterising the connectivity threshold for random graphs on the $1$ -skeleton of the n-dimensional cube. Our main result can also be seen as a cubical counterpart to the Linial–Meshulam theorem for random $2$ -dimensional simplicial complexes. However, the models exhibit strikingly different behaviours. We show that if $p> 1 - \sqrt {1/2} \approx 0.2929$ , then with high probability the fundamental group is a free group with one generator for every maximal $1$ -dimensional face. As a corollary, homology vanishing and simple connectivity have the same threshold, even in the strong ‘hitting time’ sense. This is in contrast with the simplicial case, where the thresholds are far apart. The proof depends on an iterative algorithm for contracting cycles – we show that with high probability, the algorithm rapidly and dramatically simplifies the fundamental group, converging after only a few steps.

Systemic Risk of Contract

Complexity and uncertainty define our world, now more than ever. Scholars and practitioners celebrate modular contract design as an especially effective tool to manage these challenges. Modularity divides complex structures into relatively discrete, independent components with simple connections. The benefits of this fundamental drafting approach are intuitive. Lawyers divide contracts into sections and provisions to make them easier to understand and reduce uncertainty. Dealmakers constructing complex transactions use portable agreements as building blocks to reduce drafting costs and enable innovation. Little attention, however, has been paid to the risks introduced by modularity in contracts. This Article demonstrates how this touted and now-ingrained drafting approach introduces new forms of the very costs it seeks to minimize. The Article is the first to identify the types of risks introduced by modularity at the intra-contract level, among provisions, and the inter-contract level, among agreements that constitute deals. The Article groups these risks into three categories: First, “intertextualism,” which occurs when the operation of a discrete, or even standard, provision seems clear in isolation but is made uncertain by the presence of other discrete terms. Second, “modular drift,” which occurs when drafters transplant provisions specific to one transactional context into another transactional context, introducing uncertainty. Third, “latent triggers,” which occur when compartmentalization invites error or obscures a nuance in the interaction among discrete provisions. The Article urges courts to articulate distinctions between contract types and offers tools to contract drafters to mitigate uncertainty. It also makes a theoretical contribution with implications for contract doctrine and contract innovation. It shows how modularity can disrupt seemingly stable, standardized provisions, diminishing their certainty and imposing information costs on future drafters who seek to rely on precedent provisions or agreements. It thereby identifies a critical dimension of contract risk that complicates the balancing of standardization and private choice in contracts.

Архітектурні особливості систем розподілених обчислень

Recently, there has been an increasing penetration of information technology in almost all areas of human life. The development of information technology is associated with the emergence of new tasks that require significant computing resources and can not be solved on a conventional computer. A large amount of computing requires the creation of so-called supercomputers, which is not always technically possible. But there is another way to solve this problem, when a complex task is divided into a number of subtasks that run in parallel. And here come in handy distributed computing system. In general, a distributed computing system is a virtual machine that consists of several nodes connected by a network. That is, a certain three-dimensional problem is divided into several simple subtasks and connections are established between them. But such a system will be operational only when the tasks between the nodes are distributed correctly, and the sequence of their execution will take place according to a given algorithm. The article analyzes the architectural features of distributed computing systems. The main task of distributed computing technologies is to provide access to globally distributed resources and solve problems that require significant computing power and can not be implemented on a conventional computer. The complexity of global tasks is due to the fact that the necessary data can be accessed on different computers. In addition, distributed computing systems, which are formed from autonomous resources, can change their architecture dynamically. Management of such distributed computer systems requires the search for new computational models and the search for architectural solutions to build new systems that would meet the current level of development of information technology.

Augmented Reality to Teach Arthroscopic Shoulder Surgery in Developing Countries

Arthroscopy has traditionally been taught to residents or other surgeons through one-on-one in person guided training in the operating room. Simulators have also been used to increase the availability of exposure to arthroscopy training. However, these simulators have significant limitations and cannot be definitively correlated to improvement in arthroscopy skills in the operating room. In developing countries, arthroscopic surgical skills are not often emphasized in training programs and in particular, shoulder arthroscopic skills may or may not be taught. The use of telementoring through augmented reality (AR) has been demonstrated in Orthopaedic education. In the context of arthroscopy, AR can facilitate the collaborative efforts of improving surgical teaching methods through visual and audio interactions in the operating room, regardless of geographic boundaries. AR is both an economical and easily-reproducible teaching tool, making it readily accessible to developing nations across the globe. We have developed a private platform (SurgTime) using augmented reality in the operating room from a remote location. The purpose of our study is to determine whether the platform is reliable and if it may have usefulness in teaching arthroscopic shoulder surgical skills in developing countries. Ten Orthopaedic surgeons with an interest in shoulder surgery were recruited for the project. They were all part of a collaborative effort initially sponsored by the American Academy of Orthopaedic Surgeons (AAOS) and the Romanian Orthopaedic and Traumatologic Society (SROT) to bring modern shoulder surgical techniques to Romania. Over a 5 year period, 8 Romanian surgeons, one Serbian surgeon and one Bosnian surgeon were enlisted in the program. On a bimonthly basis over a period of 3 months, the European surgeons were invited to connect via a simple internet connection to the telementoring surgeon in the United States and with real time interactive presence, were able to interact with the telementoring surgeon. Via the private platform (SurgTime), the observing surgeons were able to visualize the same arthroscopic picture that the operating surgeon was seeing, ask real time questions during the surgery and also use augmented reality (AR) graphics to point out structures or clarify surgical techniques. The observing surgeons along with the telementoring surgeon filled out a Likert-scale questionnaire regarding the educational utility, efficiency of use and safety of the system. There were 10 successful connections out of 12 attempts from the telementoring surgeon to the mentee surgeons over a 3 month period. The first two attempts were unsuccessful because of the poor connectivity of the internet via a wireless connection from the telementoring surgeon’s operating room. The next 10 straight attempts were successful once a hard wired connection was established in the operating room. Ten arthroscopic shoulder surgeries were performed and observed via the private platform on the observers’ home or office computer, cell phone, tablet or any other device that received an internet connection. There was no loss of connectivity via the telementoring surgeon and the observing surgeons for all 10 cases. There was an average of 3 surgeons viewing each surgical procedure (range 2-5). All of the observing surgeons agreed that the system was easy to use, reliable, easy to connect to, and had sufficient image resolution with no significant lag in motion or audio transmission. They also felt it was useful to highlight shoulder anatomy and pathology and to observe the telementoring surgeon’s surgical technique. The observing surgeons did not feel there were any safety concerns with the procedure nor did it interfere with the surgical procedure. The single telementoring surgeon (senior author) also agreed that the system was easy to use, reliable, easy to connect to, and had sufficient image resolution with no significant lag time in motion or audio transmission. He felt it was useful to not only highlight shoulder anatomy and pathology but also to demonstrate surgical techniques. The telementoring surgeon also did not feel there were any safety concerns with the procedure nor did it interfere with the surgical procedure. Both the observing surgeons and the telementoring surgeon felt it was an effective teaching tool. The real time interactive presence (RTIP) technology using augmented reality was efficient, safe and effective as a teaching tool in teaching shoulder arthroscopy. This first trial with our platform found it to be reliable in connecting the experienced surgeon here in the United States telementoring a group of Orthopaedic surgeons learning shoulder arthroscopy in Romania, Serbia and Bosnia. Its successful application in this context has the potential to shape the future of global Orthopaedic training and in developing countries. By providing real time instruction of surgical instruction from a remote location, this technology can accelerate the learning curve of doctors in developing countries, enhance knowledge transfer and skill acquisition, and improve arthroscopic surgical technique, patient safety, and operative outcomes.

MicroSTARLING: A Millimeter Scale Self-Organizing Optical Communication Processor for Embedded Multihop Sensor and Computational Networks

In the development of small scale, networked nodes, design inspiration can be found in the decentralized and simplistic communication used by starlings in flight. Here, we present a novel node processor based on simple nearest neighbor connections to yield a self-organized linear optical sensor network. We present the processor state machine design and evaluation of the Verilog code. Each node, termed a MicroSTARLING, contains a processor fabricated using 180nm CMOS technology. The chips are 1.2mm ×1.2mm and the digital processor occupies 0.063 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> of the chip. We assemble three test bench nodes to evaluate the processor function in wired, wireless communication and fully wireless circuits. When nodes are directly wired, the MicroSTARLING processor functions with a 25MHz input clock enabling a linear multihop network readout of 8 devices in 1.8ms. With a 20 μW, 524KHz input clock, the processor requires 12 μW at 1.2V. We evaluate the processor function under optical communication obtaining 6-hops between 7 nodes with little noticeable reduction in communication quality. Our fully wireless node required 3mW of power harvested via a 940nm light emitting diode (LED) and communicated via separate LEDs. To our knowledge this is the first demonstration of more than 3 hops of linear wireless communication with a mm scale self-organizing node processor. The processor size and power make possible the concept of smart dust networks with multihop communication between nodes for an embedded wireless sensor network in biological tissue structures or as the foundation of an optical neural network for edge computing.

Electrical Measurements and Parameter Extraction of Commercial Devices Through an Automated MATLAB-Arduino System

A quick, cheap, and portable system for measuring accurately basic electrical characteristics of electronic devices is presented—using common off-the-shelf components linked through a simple breadboard. The system is controlled using a MATLAB app that communicates to an Arduino Nano that, in turn, controls two AD5761 16-bit, 20-V, digital-to-analog converters and an INA219 high-side shunt sensor for driving the voltage and measuring the current through a device under test (DUT). The raw data from the system are plotted in real time in MATLAB and are automatically saved to a.csv file based on the current date and time. For higher current devices (above 10 mA), a simple direct-wired connection between the DUT and the measurement circuit effectively eliminates the breadboard parasitic resistance. With these techniques, the system introduced here shows a negligible difference to the data measured using a Keithley 2410 sourcemeter and a B1500 semiconductor parameter analyzer, thereby presenting a cheap and reproducible alternative to high-end instruments for measuring two- and three-terminal devices.

Internal reliability of blame-related functional MRI measures in major depressive disorder

BackgroundIn major depressive disorder (MDD), self-blame-related fMRI measures have shown the potential to be used as prognostic markers for recurrence risk. Like most potential fMRI markers, however, their reliability is unclear. Here, we probed the internal reliability of self-blame-related fMRI measures, as well as the impact of different modelling approaches on reliability metrics and validity. MethodsInternal consistency (i.e. split-half reliability) was calculated for blood oxygen level-dependent (BOLD) responses and psychophysiological interactions (PPI) related to self-blame-related biases in medication-free remitted MDD participants (n = 81) and healthy controls (n = 41). Trial-length was modelled using three durations (0, 2 and 5 s), which was convolved with the haemodynamic response function (HRF) with and without time and dispersion derivatives. Intraclass correlation coefficients (ICCs) were calculated for simple contrasts examining activation to self-blaming emotions and other-blaming emotions and the more complex contrast of the subtraction-based difference between self- and other-blaming emotions within the following a priori ROIs: right superior anterior temporal lobe seed region, anterior subgenual cingulate cortex, posterior subgenual cortex and right striatum / pallidum. ResultsAcross ROIs, we obtained fair reliability (ICC ≥ 0.40) for simple, but poor reliability (ICC < 0.40) for more complex fMRI measures related to self-blame. Despite this low internal consistency of complex measures at the individual level, we observed robust activation at the group-level, reproducing previously published results. ConclusionsWhile simple BOLD contrasts had fair reliability, previously employed PPI models had poor reliability and simple connectivity measures lacked predictive validity. This calls for the development of functional connectivity measures that strike a better balance between reliability and validity for future clinical applications, which require robust measures at the individual rather than group-level.

A characterization of singular Schrödinger operators on the half-line

AbstractWe study a class of delta-like perturbations of the Laplacian on the half-line, characterized by Robin boundary conditions at the origin. Using the formalism of nonstandard analysis, we derive a simple connection with a suitable family of Schrödinger operators with potentials of very large (infinite) magnitude and very short (infinitesimal) range. As a consequence, we also derive a similar result for point interactions in the Euclidean space $\mathbb {R}^3$ , in the case of radial potentials. Moreover, we discuss explicitly our results in the case of potentials that are linear in a neighborhood of the origin.

RETRACTED: Enterprise financial risk management platform based on 5 G mobile communication and embedded system

5 G technology has been applied to the financial sector. As a mortgage and supervision of sensors, network cameras, mobile device to improve the financial performance of real-time data generated by the data, bank loan credit risk management has been used. There are many risks of financial credit in modern society, the most important of which is the financial danger on mobile Internet. In the case of mobile phone payment popularity, financial risk has also greatly improved. This makes the traditional statistics and models can not fully meet the needs of the development of modern society. Bank credit risk has also improved to some extent. Therefore, there is a practical need for a more robust risk prediction model of artificial intelligence to predict the default behavior with good accuracy and competency-based big data analytics. This paper presents data mining method optimization and 5 G mobile communications and embedded systems commercial banks, based on financial risk management. It is safe to protect personal privacy, consider these requirements 5 G system design. To successfully connect to the ability to make money, telecom service providers need to ask their players to match their products and the industry. In addition to simple connections, they need a unified high-level function, such as coordination of network resources, analytical capabilities, and automated business and operations. Mob ileum provides Business Assurance Analytics to improve and develop a strong customer value proposition during 5 G technologies deployment. Experimental results show that the risk management models have fast convergence, powerful forecasting capabilities, and effectively perform screening default behavior. Simultaneously, distributed significant data clusters to achieve significantly reduce the processing time model training and testing.

Critical gas velocity of hydrophobic ceramic membrane contactors for SO2 absorption

Membrane gas absorption (MGA) based on ceramic membranes is considered to be an effective technology for removing SOx from ship exhaust. To develop a convenient method for designing and amplifying a membrane contactor, the critical gas velocity was defined. Two simple connection modes, series and parallel modules, were assembled and compared with a single-tube membrane contactor. The critical gas velocity is associated with the size of the membrane element and module, based on which an empirical equation can be formulated to optimize the gas velocity in different membrane contactors. In addition, another amplifying method, using multiple tubes in one shell, was also studied with computational fluid dynamics (CFD) simulations. The results imply that the addition of baffles improves the desulfurization performance of the membrane contactor at the critical gas velocity. The methods and conclusions presented herein provide a design basis for using the contactor at an industrial scale.

Optical potentials, retarded Green's functions, and nonorthogonality

An approach is outlined to constructing an optical potential that includes the effects of antisymmetry and target recoil. It is based on the retarded Green's function, which could make it a better starting point for applications to direct nuclear reactions, particularly when extended to coupled channels. Its form retains a simple connection to folding potentials, even in the presence of three-body forces.

Classical double copy of nonsingular black holes

We apply the classical double copy procedure to a class of regular, non-singular black hole solutions. We give several examples, paying particular attention to a string-theory-corrected black hole solution emerging from T-duality. Non-perturbative stringy corrections introduce an ultraviolet (UV) zero-point length cutoff which results in non-singular black hole spacetimes. Apart from the UV regulator, the solution is equivalent to the Bardeen black hole spacetime. We extend this solution to include an asymptotic de Sitter background. All Yang-Mills field theory quantities associated with the double copy are well-behaved and finite for all values of parameters. We present a thorough analysis of the black hole horizon structure, additionally uncovering a simple yet new connection between horizons on the gravity side and electric fields on the gauge theory side of the double copy.

Effects of parcellation and threshold on brainconnectivity measures.

It is shown that the statistical properties of connections between regions of the brain and their dependence on coarse-graining and thresholding in published data can be reproduced by a simple distance-based physical connectivity model. This allows studies with differing parcellation and thresholding to be interrelated objectively, and for the results of future studies on more finely grained or differently thresholded networks to be predicted. As examples of the implications, it is shown that the dependences of network measures on thresholding and parcellation imply that chosen brain regions can appear to form a small world network, even though the network at finer scales, or ultimately of individual neurons, may not be small world networks themselves.

Design of Simple Steel Connections under Fire Temperatures

A methodology is developed for designing simple steel connections (shear tab and double angle) subjected to fire. The proposed methodology is based on quantifying the strength and stiffness of steel framed simple connections at elevated temperatures. To achieve this, first, a stiffness-based model that characterizes the rotational stiffness of simple steel connections when subjected to fire temperatures is developed. The model is capable of predicting the behavior of two widely used simple steel connections (shear tab and double angle) when subjected to fire temperatures. It incorporates the connection rotation of key component elements and the nonlinear behavior of both bolts and base materials at elevated temperatures. The model is validated against experimental results available in the literature under steady-state temperature analysis. The model covers all possible limit states and governing failure modes under different loading and temperature conditions. It can be considered a practical tool for designing simple steel connections for professional structural fire engineers in the United States. Step-by-step design examples of simple steel connections in an isolated frame are provided to illustrate the incorporation of the developed stiffness model in a fire design procedure. The presented design procedure accounts for the additional load demand on the connection during fire. This includes the load demand due to thermal expansion and beam sagging.

Braitenberg Vehicles as Computational Tools for Research in Neuroscience.

Valentino Braitenberg reported his seminal thought experiment in 1984 using reactive automatons or vehicles with relatively simple sensorimotor connections as models for seemingly complex cognitive processes in biological brains. Braitenberg's work, meant as a metaphor for biological life encompassed a deep knowledge of and served as an analogy for the multitude of neural processes and pathways that underlie animal behavior, suggesting that seemingly complex behavior may arise from relatively simple designs. Braitenberg vehicles have been adopted in robotics and artificial life research for sensor-driven navigation behaviors in robots, such as localizing sound and chemical sources, orienting toward or away from current flow under water etc. The neuroscience community has benefitted from applying Braitenberg's bottom-up approach toward understanding analogous neural mechanisms underpinning his models of animal behavior. We present a summary of the latest studies of Braitenberg vehicles for bio-inspired navigation and relate the results to experimental findings on the neural basis of navigation behavior in animals. Based on these studies, we motivate the important role of Braitenberg vehicles as computational tools to inform research in behavioral neuroscience.

Evolving network characteristics of the asian international aviation market: A weighted network approach

The air transportation industry is one big network that is expected to grow continuously, and Asia-Pacific is the fastest growing region as of 2018 data. We apply weighted network analysis to explore the key network characteristics of the Asian international passenger aviation market in 2014 and 2018. For the analysis, networks are constructed based on international passengers' origin-destination pair data from 28 Asian airlines in 2014 and 2018. Previously published social network analysis (SNA) on the air transportation network largely used unweighted centrality metrics, whereas the actual situation is a weighted network. We implement Mean Associations (MA), Triangle Betweenness Centrality (TBC), and Weighted PageRank (WPR), as new weighted centrality metrics, to effectively reflect actual passenger traffic among airports beyond simple connections. Our weighted network analysis indicates that SIN, ICN, HKG, NRT, MNL, BKK, TPE, HND, PEK, and KUL are the top-ranked hub airports, followed by SGN, PVG, CAN, DEL, SYD, KIX and CGK, and that the low-cost carriers have almost fully developed a ‘hub-and-spoke’ structure over the 4-year study period and are increasing their impact on the centrality of airports in the region.

Spatial Configuration and Extent Explains the Urban Heat Mitigation Potential due to Green Spaces: Analysis over Addis Ababa, Ethiopia

Urban green space (UGS) is considered a mitigative intervention for urban heat. While increasing the UGS coverage is expected to reduce the urban heat, studies on the effects of UGS configuration have produced inconsistent results. To investigate this inconsistency further, this study conducted a multi-spatial and multi-temporal resolution analysis in the Addis Ababa city metropolitan area for assessing the relationship between UGS patterns and land surface temperature (LST). Landsat images were used to generate land cover and LST maps. Regression models were developed to investigate whether controlling for the proportion of the green area (PGS), fragmentation, shape, complexity, and proximity distance can affect surface temperature. Results indicated that the UGS patches with aggregated, regular and simple shapes and connectivity throughout the urban landscape were more effective in decreasing the LST as compared to the fragmented and complicated spatial patterns. This finding highlighted that in addition to increasing the amount of UGS, optimizing the spatial structure of UGS, could be an effective and useful action to mitigate the urban heat island (UHI) impacts. Changing the spatial size had a significant influence on the interconnection between LST and UGS patterns as well. It also noted that the spatial arrangement of UGS was more sensitive to spatial scales than that of its composition. The relationship between the spatial configuration of UGS and LST could be changed when applying different statistical methods. This result underlined the importance of controlling the effects of the share of green spaces when calculating the impacts of the spatial configuration of UGS on LST. Furthermore, the study highlighted that applying different statistical approaches, spatial scale, and coverage of UGS can help determine the effectiveness of the association between LST and UGS patterns. These outcomes provided new insights regarding the inconsistent findings from earlier studies, which might be a result of the different approaches considered. Indeed, these findings are expected to be of help more broadly for city planning and urban heat mitigation.

Crashworthiness design and experimental validation of a novel collision post structure for subway cab cars

This paper proposes a novel collision post structure designed to improve the crashworthiness of subway cab cars. The structure provides two innovative features: 1) a simpler connection between the post and the car roof, which gives a more reasonable load transfer path to reduce the stress concentration at the joint; and 2) a stiffness induction design that provides an ideal deformation model to protect the safe space of the cab cars. The novel collision post structure was evaluated with finite element analysis, and a prototype cab car was mechanically tested. The results demonstrate that the deformation response was stable and agreed well with the expected ideal mode. The maximum load was 874.17 kN and the responses remained well above the elastic design load of 334 kN as required by the design specification. In addition, there was no significant tearing failure during the whole test process. Therefore, the novel collision post structure proposed has met the requirements specified in new standard to improve the crashworthiness of subway cab cars. Finally, the energy absorption efficiency and light weight design highlights were also summarized and discussed.

A versatile and low-cost chip-to-world interface: Enabling ICP-MS characterization of isotachophoretically separated lanthanides on a microfluidic device

Microfluidics offer novel and state-of-the-art pathways to process materials. Microfluidic systems drastically reduce timeframes and costs associated with traditional lab-scale efforts in the area of analytical sample preparations. The challenge arises in effectively connecting microfluidics to off-chip analysis tools to accurately characterize samples after treatment on-chip. Fabrication of a chip-to-world connection includes one end of a fused silica capillary interfaced to the outlet of a microfluidic device (MFD). The other end of the capillary is connected to a commercially available CEI-100 interface that passes samples into an inductively coupled plasma mass spectrometer (ICP-MS). This coupling creates an inexpensive and simple chip-to-world connection that enables on-chip and off-chip methods of analyzing the separation of rare earth elements. Specifically, this is demonstrated by utilizing isotachophoresis (ITP) on a microfluidic chip to separate up to 14 lanthanides from a homogenous sample into elementally pure bands. The separated analyte zones are successfully transferred across a 7 nL void volume at the microchip-capillary junction, such that separation resolution is maintained and even increased through the interface and into the ICP-MS, where the elemental composition of the sample is analyzed. Lanthanide samples of varying composition are detected using ICP-MS, demonstrating this versatile and cost-effective approach, which maintains the separation quality achieved on the MFD. This simple connection enables fast, low-cost sample preparation immediately prior to injection into an ICP-MS or other analytical instrument.

Bayesian Estimation of Correlation Matrices of Longitudinal Data

Estimation of correlation matrices is a challenging problem due to the notorious positive-definiteness constraint and high-dimensionality. Reparameterizing Cholesky factors of correlation matrices in terms of angles or hyperspherical coordinates where the angles vary freely in the range [0,π) has become popular in the last two decades. However, it has not been used in Bayesian estimation of correlation matrices perhaps due to lack of clear statistical relevance and suitable priors for the angles. In this paper, we show for the first time that for longitudinal data these angles are the inverse cosine of the semi-partial correlations (SPCs). This simple connection makes it possible to introduce physically meaningful selection and shrinkage priors on the angles or correlation matrices with emphasis on selection (sparsity) and shrinking towards longitudinal structure. Our method deals effectively with the positive-definiteness constraint in posterior computation. We compare the performance of our Bayesian estimation based on angles with some recent methods based on partial autocorrelations through simulation and apply the method to a data related to clinical trial on smoking.