Different Types Of Connections Research Articles

Stochastic finite element analysis of structural systems with partially restrained connections subjected to seismic loads

The present paper investigates the stochastic seismic responses of steel structure systems with Partially Restrained (PR) connections by using Perturbation based Stochastic Finite Element (PSFEM) method. A stiffness matrix formulation of steel systems with PR connections and PSFEM and MCS formulations of structural systems are given. Based on the formulations, a computer program in FORTRAN language has been developed, and stochastic seismic analyses of steel frame and bridge systems have been performed for different types of connections. The connection parameters, material and geometrical properties are assumed to be random variables in the analyses. The Kocaeli earthquake occurred in 1999 is considered as a ground motion. The connection parameters, material and geometrical properties are considered to be random variables. The efficiency and accuracy of the proposed SFEM algorithm are validated by comparison with results of Monte Carlo simulation (MCS) method.

Optimization of MANET connectivity via smart deployment/movement of unmanned air vehicles

Unmanned air vehicles (UAVs) can provide important communication advantages to ground-based wireless ad hoc networks. In this paper, the location and movement of UAVs are optimized to improve the connectivity of a wireless network. Four types of network connectivity are quantified: global message connectivity, worst-case connectivity, network bisection connectivity, and <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</i> -connectivity. The problems of UAV deployment and movement are formulated to improve the different types of connectivity. Both problems are <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">NP</i> -hard. For the deployment case, some heuristic adaptive schemes are proposed to yield simple but effective solutions. In addition, a closed-form solution for the two-node one-UAV case is provided. For <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</i> -connectivity, we propose an algorithm that improves connectivity using Delaunay triangulation. To optimize the UAV movement, an algorithm that tracks changes in the network topology is constructed. The simulation results show that by only deploying a single UAV, the global message network connectivity and the worst-case network connectivity can be improved by up to 109% and 60%, respectively. The network bisection connectivity and the <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</i> -connectivity can also be significantly improved.

Industrial relationships and the effects of different types of connections

Emphasizing the primary and secondary functions in business networks, this paper is based on the presumption that the primary function of the focal dyadic relationship is connected to business, political, ancillary and competitive relationships, i.e. what has been denoted as the secondary function. The question is how these secondary functions affect the primary function. The conceptual view developed for the focal dyadic relationship is founded on the two key relationship concepts of trust and commitment. The empirical study is based on a survey of 353 firms and their most important customer relationships. The analysis examines nine hypotheses through a structural model in LISREL. Conclusions from the statistical test show the heterogeneity in the impacts of these different types of connections on trust and commitment. Knowledge of the impact of these connections can aid the further understanding of relationship connections and also assist business firms in developing strategies towards these units.

Technology And The Way We Think

TECHNOLOGY AND THE WAY WE THINK Mia Krxtzk ”Are [modern tools] helping our brains develop or can there be negative consequences from our exposure to technology?” The development of technology has been linked to an increase in human cognitive abilities. In ”Pa— leolithic Technology and Human Evolution,” Stanley H. Ambrose traces the human biological and cultural evolution due to technology. Starting around 2.5 mil- lion years ago, early humans began to see an increase in brain size, population size, and geographic range. At that time stone tool technology was being devel- oped. By creating better tools, humans had greater ac- cess to food sources that were able to support the high metabolic demands of a larger brain size. Amborse also suggests that language and composite—tool mak- ing coevolved about 300,000 years ago. Both speech and composite tool—making involve nonrepetitive mo- tor control, and they are both controlled by adjacent areas of the interior frontal lobe (Ambrose 2001). Not only that, but the assembly of the tools from smaller units is similar to the assembly of words from sounds and sentences or phrases from words. Ambrose also points out that composite tool manufacture contrib- uted to the evolution of the frontal lobe, which is in- volved in planning. In Making Silent Stones Speak, Kathy Schick and Nicholas Patrick Toth provide more reasons for the cognitive developments that followed the use of tools. By creating tools, humans had to con- ceptualize possible uses for them as well as the time and the place to use them. They also had to think about the resources needed to make the tools and fi- nally how to make tools with other tools. Given the theories on early human tool use, it is easy to wonder how the use of modern ”tools” is in- fluencing us. Are they helping our brains develop or can there be negative consequences from our exposure to technology? Business, culture, and technology writer Nicholas Carr points out the negative aspects of the internet. In an article for the Atlantic Monthly, ”Is Google Making Us Stupid?” Carr expresses his concern for the frag- mented attention and lack of concentration he thinks resulted from regular internet use. He provides anec- dotal evidence of people&#39;s concentrations dwindling with the expansion of the internet. In addition to that, he cites a study done by scientists at the University Col- lege London on online research habits. They looked at the logs of two popular research sites and found that people tend to skim articles instead of reading them in depth. Also, when visitors saved a long article, there is no evidence that they went back to read it. It seems that with the vast amount and instant availability of information, skimming has replaced concentrated reading. As for the question of whether reading more articles makes up for the fact that they are not read in depth individually, Carr argues (with the help of cog- nitive neuroscientist, Maryanne Wolf) that our ability to make rich mental connections stems from concen- trated reading. Despite the fact that there are certain drawbacks to modern technology, perhaps we are learning to think in ways that are just as rewarding. Though the internet may not be a good medium for the rich men- tal connections of deep reading, maybe we will learn to make different types of connections through our exposure to a broad range of information. We might be able to see general patterns in information or con- nect two seemingly disparate topics. It is hard to find evidence for such occurrences; however, there is evi- dence that surfing the internet activates parts of the brain that are different from those activated by more traditional mediums. Recent findings suggest that internet surfing could be good for middle—aged and older people. Researchers at the University of Califor- nia Los Angeles found that search- ing the web activated areas in the brain associated with controlled d e c i s i o n BERKELEY SCIENTIFIC JOURNAL - TECHNOLOGY AND HUMAN INTERACTION - FALL 2009 - VOLUME 13 ° IssUE 1 - 39

Hop, step, jump! Building social capital by learning through bridging, bonding and linking

Studies on social capital have produced major evidence for the contention that a firm's social capital has an important implication on organisational performance and innovation (Leana and Van Buren, 1999). More recently, there is research that suggest that there are highly significant links between people's network and their learning (Van der Krogt, 1998). Utilising individual knowledge and skills is increasingly becoming a core task in the field of Human Resource Development (HRD). Herein, the skills and knowledge that is created within organisations can be seen as created through groups rather than by isolated individuals (Field, 2005). The premise of this study was that within the organisational context, the ability for an individual to acquire new skills and knowledge depends on different types of connections between organisational members. In turn, this is effected by the composition of social capital. The underlying reason of this premise is that individuals construct their own organisational context in which the acquirement of skills and knowledge takes place. The more connected employees are with others in the organisational context, the more likely they will be knowledge productive or innovative. These inter-person connections in organisations prove to be a major vehicle to organise and to understand work-related learning processes.

Understanding connections in the school mathematics curriculum

I identify and discuss ways in which different types of connections are described in the South African mathematics National Curriculum Statement and its related documents, particularly at the Further Education and Training (FET) level. I argue that connections are central to the way the discipline of mathematics, its learning outcomes, and assessment standards are conceptualised. The notions of representation and integration are found to be key aspects in understanding connections in mathematics. Using these two notions, I then analyse connections in the National Curriculum Statement and its related documents. Finally, theoretical and practical implications of connections in the curriculum are identified.

Autoregressive modelling of species richness in the Brazilian Cerrado

Spatial autocorrelation is the lack of independence between pairs of observations at given distances within a geographical space, a phenomenon commonly found in ecological data. Taking into account spatial autocorrelation when evaluating problems in geographical ecology, including gradients in species richness, is important to describe both the spatial structure in data and to correct the bias in Type I errors of standard statistical analyses. However, to effectively solve these problems it is necessary to establish the best way to incorporate the spatial structure to be used in the models. In this paper, we applied autoregressive models based on different types of connections and distances between 181 cells covering the Cerrado region of Central Brazil to study the spatial variation in mammal and bird species richness across the biome. Spatial structure was stronger for birds than for mammals, with R(2) values ranging from 0.77 to 0.94 for mammals and from 0.77 to 0.97 for birds, for models based on different definitions of spatial structures. According to the Akaike Information Criterion (AIC), the best autoregressive model was obtained by using the rook connection. In general, these results furnish guidelines for future modelling of species richness patterns in relation to environmental predictors and other variables expressing human occupation in the biome.

A Noncooperative Game-Theoretic Framework for Radio Resource Management in 4G Heterogeneous Wireless Access Networks

Fourth generation (4G) wireless networks will provide high-bandwidth connectivity with quality-of-service (QoS) support to mobile users in a seamless manner. In such a scenario, a mobile user will be able to connect to different wireless access networks such as a wireless metropolitan area network (WMAN), a cellular network, and a wireless local area network (WLAN) simultaneously. We present a game-theoretic framework for radio resource management (that is, bandwidth allocation and admission control) in such a heterogeneous wireless access environment. First, a noncooperative game is used to obtain the bandwidth allocations to a service area from the different access networks available in that service area (on a long-term basis). The Nash equilibrium for this game gives the optimal allocation which maximizes the utilities of all the connections in the network (that is, in all of the service areas). Second, based on the obtained bandwidth allocation, to prioritize vertical and horizontal handoff connections over new connections, a bargaining game is formulated to obtain the capacity reservation thresholds so that the connection-level QoS requirements can be satisfied for the different types of connections (on a long-term basis). Third, we formulate a noncooperative game to obtain the amount of bandwidth allocated to an arriving connection (in a service area) by the different access networks (on a short-term basis). Based on the allocated bandwidth and the capacity reservation thresholds, an admission control is used to limit the number of ongoing connections so that the QoS performances are maintained at the target level for the different types of connections.

‘Real’ Social Capital in Bali: Is it Different From ‘the Literature’?

The research reported in this paper focuses on social capital in two of six sites from a larger project concerning the role of communities in managing plant pests and diseases in Australia and Indonesia. In these two Balinese sites, the focus is on the nature and role of interactive ties in the overall strategies community members utilise in their identification and management of plant pests and diseases. The established position on bonding, bridging and linking ties is represented by Woolcock and Narayan (2000) and Stone and Hughes (2001). However, in Australian work, Leonard and Onyx (2003) test the notion that bridging and bonding are two different types of connections, and suggest that ‘...people prefer to bridge through their strong ties’ (p. 225). A greater on the ground understanding of the ‘real’ nature of social capital’s network tie qualities is warranted, and would inform the accuracy of the ‘real’ nature of interactive ties, as well as the ways social capital is measured and judged. This paper explores the ‘on the ground’ nature of bonding, bridging and linking ties through reporting on data from a comprehensive multi methods study of two Balinese communities. It describes the nature of the ‘real’ social capital in these communities and suggests how it might vary from the social capital as described in ‘the literature’.

Collective Langevin dynamics of flexible cytoskeletal fibers

We develop a numerical method to simulate mechanical objects in a viscous medium at a scale where inertia is negligible. Fibers, spheres and other voluminous objects are represented with points. Different types of connections are used to link the points together and in this way create composite mechanical structures. The motion of such structures in a Brownian environment is described by a first-order multivariate Langevin equation. We propose a computationally efficient method to integrate the equation, and illustrate the applicability of the method to cytoskeletal modeling with several examples.

Binomial parameters differ across neocortical layers and with different classes of connections in adult rat and cat neocortex

Binomial model-based analysis compared excitatory connections involving different classes of neurons in different neocortical layers. Single-sweep excitatory postsynaptic potentials (EPSPs) from dual intracellular recordings in adult cat and rat slices were measured. For data subsets corresponding to first EPSPs exhibiting different degrees of posttetanic potentiation and second, third etc. EPSPs in trains at different interspike intervals, coefficient of variation (CV), transmission failure rates (F), variance (V), and V/M were plotted against mean EPSP amplitude (M). Curves derived from binomial models in which subsets varied only in p (release probability) were fit and parameters q (quantal amplitude), and n (number of release sites) were estimated. Estimates for q and n were similar for control subsets and subsets recorded during Ca(2+) channel blockade, only p varied. Estimates from the four methods were powerfully correlated, but when CV, F, V, and V/M were plotted against M, different types of connections occupied different regions of parameter space. Comparisons of linear fits to V/M against M plots and of parameter estimates indicated that these differences were significant. Connections between pyramids in different layers and inputs to different cell classes in the same layer differed markedly. Monte Carlo simulations of more complex models subjected to simple binomial model-based analysis confirmed the significance of these differences. Binomial models, either simple, in which p and q are identical at all terminals involved, or more complex, in which they differ, adequately describe many neocortical connections, but each class uses different combinations of n, mean p, and mean q.

Standing Waves and Traveling Waves Distinguish Two Circuits in Visual Cortex

The visual cortex represents stimuli through the activity of neuronal populations. We measured the evolution of this activity in space and time by imaging voltage-sensitive dyes in cat area V1. Contrast-reversing stimuli elicit responses that oscillate at twice the stimulus frequency, indicating that signals originate mostly in complex cells. These responses stand clear of the noise, whose amplitude decreases as 1/frequency, and yield high-resolution maps of orientation preference and retinotopy. We first show how these maps are combined to yield the responses to focal, oriented stimuli. We then study the evolution of the oscillating activity in space and time. In the orientation domain, it is a standing wave. In the spatial domain, it is a traveling wave propagating at 0.2-0.5 m/s. These different dynamics indicate a fundamental distinction in the circuits underlying selectivity for position and orientation, two key stimulus attributes.

Integration of IEEE 802.11 WLANs with IEEE 802.16-based multihop infrastructure mesh/relay networks: A game-theoretic approach to radio resource management

One of the promising applications of IEEE 802.16 (WiMAX)-based wireless mesh/relay networks is to provide infrastructure/backhaul support for IEEE 802.11-based mobile hotspots. In this article we present an architecture for integrating IEEE 802.11 WLANs with IEEE 802.16-based multihop wireless mesh infrastructure to relay WLAN traffic to the Internet. The major research issues in this integrated architecture are outlined and related work is reviewed. A game-theoretic model is developed for radio resource management in this integrated network architecture. In particular, a multiplayer bargaining game formulation is used for fair bandwidth allocation and optimal admission control of different types of connections (e.g., WLAN connections, relay connections, and connections from standalone subscriber stations) in an IEEE 802.16 base station/mesh router. Both connection-level and inconnection-level performances for this bandwidth management and admission control framework are presented

Visualisation of the pisotriquetral joint through standard portals for arthroscopy of the wrist

Disorders of the pisotriquetral joint are well recognised as the cause of pain on the ulnar side of the wrist. The joint is not usually examined during routine arthroscopy because it is assumed to have a separate joint cavity to the radiocarpal joint, although there is often a connection between the two. We explored this connection during arthroscopy and in fresh-frozen cadaver wrists and found that in about half of the cases the pisotriquetral joint could be visualised through standard wrist portals. Four different types of connection were observed between the radiocarpal joint and the pisotriquetral joint. They ranged from a complete membrane separating the two, to no membrane at all, with various other types of connection in between. We recommend that inspection of the pisotriquetral joint should be a part of the protocol for routine arthroscopy of the wrist.

Synthesis and Magnetic Properties of an Amine-Templated Fe2+ (S = 2) Sulfate with a Distorted Kagome Structure

An organically templated iron(II) sulfate of the composition [H3N(CH2)2NH2(CH2)2(NH3]4[Fe(II)9F18(SO4)6].9H2O with a distorted Kagome structure has been synthesized under solvothermal conditions in the presence of diethylenetriamine. The distortion of the hexagonal bronze structure comes from the presence of two different types of connectivity between the FeF4O2 octahedra and the sulfate tetrahedra. This compound exhibits magnetic properties different from those of an Fe(II) compound with a perfect Kagome structure and is a canted antiferromagnet at low temperatures.

Solar cycles in global temperatures

We study variations of solar activity (sunspot numbers W) and anomaly of global temperature (GT) to detect a connection of their time variations on different time scales (in- cluding trends) to understand cause of global warming. We use a method of non-linear spectral analysis that is capable of making a self-consistent selection of trends, non-stationary oscillations and identifiing time intervals of development of non-linear processes (appearence of oscillations of large amplitude) in data. Analysis shows that trends of both spectra contribute main part to the data changes and show correlated increasing of W and GT during the studied interval. Cause of Maunder Minimum and present global warming is regime change (from epoch of damping to epoch of building up) of the powerfull oscillations at T = 1000 yr. from the GT spectrum. Besides, time changes of GT and W has different type of connection in different range of periods T: non-stationary oscillations from the spectra of W and GT at T = 10 yr. and T = 30 yr. vary in opposite phase, at T = 22 yr. vary in phase. The latter means different influence of odd and even 11-yr solar cycles on anomaly of GT (warming and cooling accordingly).

A new method of monitoring the interchangeability of precision parts in connections

New methods of monitoring the interchangeability of parts on the basis of their functional properties in connections are considered. An application of gauge blocks for use in modeling different types of connections of precision parts is described and an estimate of the attainable precision of their interchangeability is given.

Unified block shear equation for achieving consistent reliability

Equations in design standards for block shear vary widely and, when used for different types of connections, they provide significantly inconsistent levels of safety. In many cases reported in the literature, recommended changes are intended to address a specific deficiency without assessing the overall impact on design in a broader sense. Moreover, a reliability study is required to fully assess the level and consistency of resulting safety indices. To resolve these shortcomings and inconsistencies, a database of 205 block shear tests on gusset plates, angles, tees, and coped beams from 17 different research programs was compiled and a reliability study conducted. From this study, as well as from the failure modes observed in the tests, a unified block shear equation is proposed that provides much more consistent test-to-predicted block shear capacity ratios over a wide variety of connection types, geometries, and steel grades. The unified equation also results in consistent safety indices for gusset plates, angles, tees, and coped beams with either one or two lines of bolts, a goal that is not achieved by other methods available. A resistance factor is recommended for design that will achieve an appropriate level of safety.

Ranging behaviour of greater flamingos during the breeding and post-breeding periods: Linking connectivity to biological processes

Connectivity among habitat patches has mainly been studied in relation to species-specific behaviours. However, the movements of animals among patches may have different functions, and tolerance to gaps between habitat patches may vary between these functions. We tracked the movements of greater flamingos during the breeding and post-breeding periods with the aim of illustrating how the degree of connectivity may vary depending on the biological processes underlying the movements between wetlands. Most foraging sites used by breeding adults in a colony in southern Spain were within 200 km of the colony site, although some birds eventually moved 400 km. After the breeding season, the adults remained for several weeks in specific wetlands, moving to other sites located 280–2100 km away to overwinter. During these movements the birds may use stopover sites, the conservation of which may be critical to facilitate long-range movements. Our results suggest that wetland connectivity during chick rearing does not seem to be determined by whether or not central-place foraging flamingos are able to reach wetlands located at the longest distance that they are able to fly during non-stop flights (>1000 km), but by whether they are able to sustain the energetic costs derived from frequent commuting. In contrast, long-distance movements were occasionally undertaken during the post-breeding period. The energetic costs of such flights could be paid by flamingos because these movements were infrequent. Thus, in the case of flamingos, connectedness thresholds between wetlands vary depending on the biological process involved (chick rearing or post-breeding movements). This emphasizes the need to consider different types of connectivity in conservation planning.

First principles modeling of intermediate range order in amorphous SiSe 2

The structural properties of amorphous SiSe 2 are studied by performing extensive first-principle molecular dynamics simulations. Comparison with experiments in terms of total neutron scattering factor and nuclear magnetic resonance data confirms the reliability of our model. Partial pair correlation functions and ring statistics are used to identify the structural units whose spatial organization gives raise to the intermediate range order. An accurate analysis reveals that amorphous SiSe 2 is largely a chemically ordered system consisting mainly of a network of silicon centered tetrahedra. Different types of connections among the tetrahedra can be identified and classified. In particular edge-sharing connections seem to play a fundamental role in the establishment of the intermediate range order and in the appearance of the first sharp diffraction peak in the total neutron scattering factor.