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This paper concentrates on establishing a connectivity graph between building entities to model hazard flow and the interaction between pedestrians and hazards. Although three different ways are explored, the Uniform raycast-based approach resulted in being the most robust. We establish a link between hazards, indoor spaces and pedestrians through voxels, where navigable voxels are first derived, and further classified as IfcSpace and IfcDoor. In the end, only voxels with unique properties are kept, being < 1% of the total number of a building. Once the connectivity graph and voxels are identified the interaction between pedestrians and hazards is presented as straightforward. [ABSTRACT FROM AUTHOR]

The article presents a methodology for supervised regionalization of data on a spatial domain. Defining a spatial process at multiple scales leads to the famous ecological fallacy problem. Here, we use the ecological fallacy as the basis for a minimization criterion to obtain the intended regions. The Karhunen-Loève Expansion of the spatial process maintains the relationship between the realizations from multiple resolutions. Specifically, we use the Karhunen-Loève Expansion to define the regionalization error so that the ecological fallacy is minimized. The contiguous regionalization is done using the minimum spanning tree formed from the spatial locations and the data. Then, regionalization becomes similar to pruning edges from the minimum spanning tree. The methodology is demonstrated using simulated and real data examples. [ABSTRACT FROM AUTHOR]

Multi-view Stereo (MVS) meshes suffer from occlusions or missing data, making most surface reconstruction methods invalid. Due to data imperfections, existing methods, just like PolyFit, have made a trade-off between reconstruction accuracy and time consumption. We propose a novel approach that automatically reconstructs a building surface model from raw triangular mesh with data incompleteness. Unlike existing methods that extract high-quality primitives, our method focuses on assemblies of primitives to control the level of geometric detail in the reconstructed models. We design a topological relationship of the primitives to form a plane connection graph. To be precise, we first combine the scalability of shapes with plane primitives. Then strong and soft connections between primitives are constructed by calculating the confidence of the plane intersection in space. Furthermore, the topological relations of all primitives are encoded into an undirected graph. Finally, a watertight and manifold model is extracted from the faces of a candidate set by energy minimization. Experiments on the Helsinki 3D dataset demonstrate the superiority of our method in time consumption and reconstruction error, as measured by Hausdorff distance. Our method outperforms other primitive-based algorithms in handling non-planar structures. Even when dealing with imperfect data, a watertight model is still obtained. [Display omitted] • Due to the occlusion caused by various reasons such as trees, we designed a lightweight data structure and general strategy to rectify the building data defects. A confidence strategy combining graph structure is proposed, which reduces the time consumption compared with the state-of-art methods and captures more accurate geometric details within the reconstruction pipeline to generate building models with higher levels of detail. [ABSTRACT FROM AUTHOR]

In this work we continue the investigation of different approaches to conception and modelling of composite materials. The global method we focus on, is called ‘stochastic homogenization’. In this approach, the classical deterministic homogenization techniques and procedures are used to compute the macroscopic parameters of a composite starting from its microscopic properties. The stochastic part is due to averaging over some series of samples, and the fact that these samples fit into the concept of RVE (Representative Volume Element) in order to reduce the variance effect. In this article, we present a novel method for computation of effective electric properties of composites – it is based on the analysis of the connectivity graph (and the respective adjacency matrix) for each sample of a composite material. We describe how this matrix is constructed in order to take into account complex microscopic geometry. We also explain what we mean by homogenization procedure for electrical conductivity, and how the constructed matrix is related to the problem. The developed method is applied to a test study of the influence of micromorphology of composites materials on their conductivity. [ABSTRACT FROM AUTHOR]

Although, in most animals, brain connectivity varies between individuals, behaviour is often similar across a species. What fundamental structural properties are shared across individual networks that define this behaviour? We describe a probabilistic model of connectivity in the hatchling Xenopus tadpole spinal cord which, when combined with a spiking model, reliably produces rhythmic activity corresponding to swimming. The probabilistic model allows calculation of structural characteristics that reflect common network properties, independent of individual network realisations. We use the structural characteristics to study examples of neuronal dynamics, in the complete network and various sub-networks, and this allows us to explain the basis for key experimental findings, and make predictions for experiments. We also study how structural and functional features differ between detailed anatomical connectomes and those generated by our new, simpler, model (meta-model).

Data grid is emerging as the main part of the infrastructure for large-scale data intensive applications such as high energy physics and bioinformatics. The deployment of such infrastructures has allowed users of a grid site to gain access to a large amount of distributed data. Data replication is a key issue in a data grid and could be applied intelligently because it reduces data access time and bandwidth consumption for each grid site. In this paper, we introduce a new dynamic data replication algorithm named Popular Groups of Files Replication (PGFR). Our proposed algorithm is based on an assumption: users in a Virtual Organization have similar interests in groups of files. Based on this assumption, and file access history, PGFR builds a connectivity graph to recognize a group of dependent files in each grid site and replicates the most Popular Groups of Files to each grid site, thus increasing the local availability. We used OptorSim simulator to evaluate the efficiency of PGFR algorithm. The simulation results show that PGFR achieves better performance compared to the existing algorithm; PGFR minimized the mean job execution time, bandwidth consumption, and avoiding unnecessary replication. [ABSTRACT FROM AUTHOR]

We present a graph-theoretical interpretation of the recently developed interface theory of single zigzag chains N(n) in form of connectivity graphs. A remarkable property of the connectivity graphs is the possibility of constructing the full set of Clar covers of N(n) as the complete set of walks on these graphs. Connectivity graphs can be constructed in a direct form, in which the number of vertices is growing linearly with the length n of N(n), and in a reduced form, in which the number of vertices is independent of the actual length of the chain. The presented results can be immediately used for the determination of the Zhang-Zhang (ZZ) polynomials of N(n) in an easy and natural manner. Two techniques for computing the ZZ polynomial are proposed, one based on direct recursive computations and the other based on a general solution to a set of recurrence relations. Generalization of the interface theory to arbitrary benzenoid structures, the construction of associated connectivity graphs, and techniques for the computation of the associated ZZ polynomials will be presented in the near future. [ABSTRACT FROM AUTHOR]

In recent years data grids have been deployed and grown in many scientific experiments and data centers. The deployment of such environments has allowed grid users to gain access to a large number of distributed data. Data replication is a key issue in a data grid and should be applied intelligently because it reduces data access time and bandwidth consumption for each grid site. Therefore this area will be very challenging as well as providing much scope for improvement. In this paper, we introduce a new dynamic data replication algorithm named Popular File Group Replication, PFGR which is based on three assumptions: first, users in a grid site (Virtual Organization) have similar interests in files and second, they have the temporal locality of file accesses and third, all files are read-only. Based on file access history and first assumption, PFGR builds a connectivity graph for a group of dependent files in each grid site and replicates the most popular group files to the requester grid site. After that, when a user of that grid site needs some files, they are available locally. The simulation results show that our algorithm increases performance by minimizing the mean job execution time and bandwidth consumption and avoids unnecessary replication. [ABSTRACT FROM AUTHOR]

In order to systematically analyze Internet traffic features, this paper researched the taxonomy of traffic features based on the objects used for building traffic features,and overviewed the related traffic features in each category. It further analyzed the stability of traff ic features, the impact of packet sampling, network environment and obfuscating on traffic features. And then it compared the different kinds of traffic features from classification accuracy .stability, timeliness and granularity. Finally, this paper concluded future works about traffic features. [ABSTRACT FROM AUTHOR]

We consider the static and dynamic characteristics of interatomic bonding in the region of nonvalent interactions of a nitro group in the crystal of complex [Fe(NO)(SCHNO)]. Based on results obtained by modeling vibrations within the framework of the density functional theory and those of multitemperature X-ray diffraction studies, a purely vibrational nature of the abnormally large atomic displacement ellipsoid of one of the O atoms of the nitro group was revealed and a model for the influence of peculiar features of intermolecular bonding on the observed dynamics was suggested. Using topological analysis of the experimental electron density function, we studied the nature of nonvalent intermolecular interactions of the nitro group and evaluated their strength and directionality in the equilibrium state. The dependence of the 'pseudodegeneracy' region of atom-atom interaction on the nature of the interaction revealed and a method for determining the vibrational smearing of interactions was suggested, which allows one to analyze the stability of the connectivity graph of the crystal. [ABSTRACT FROM AUTHOR]

Globalization, densification, and the urban growth require the establishment of an interdisciplinary set of tools, which will allow the analysis of the morphological, spatial, social and functional qualities of the city. Space Syntax in the urban design is applied in the modelling of the human behaviour by the examination of the spatial configuration of the urban systems. Analysis of the spatial integration, connectivity and visual exposure of open spaces and paths in combination with the land use patterns indicates the areas, which facilitate the social and commercial activities. This approach is implemented on the four residential complexes of the city of Tirana. Results show the correlation between the type and location of the activities and the spatial and visual integration. The applied methodology is suitable for the preliminary comprehension of the social dimension of the urban projects at the design stage. The insights from the study are appropriate to be used as the urban planning policies in the developing countries of the Global South. • The study is focused on the exploration of socio-spatial parameters of four neighbourhoods using the Space Syntax analysis. • Integration and visual exposure analysis indicates the areas, which encourage the social and commercial activities. • Space hierarchy, intelligible street network and well-integrated large open space facilitate the liveable built environment. • Physical, social and syntactic assessment of the residential development should be prioritised by the urban policies. [ABSTRACT FROM AUTHOR]

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Abstract: The main aim of the detailed facility layout is to calculate the obstacle-avoiding Manhattan shortest path (OAMSP) between facilities. We propose a connectivity graph generation approach for OAMSP calculation. The proposed approach makes full use of the characteristics of Manhattan distance, which are different from Euclidean distance. The proposed connectivity graph contains O(N log N) vertices and edges, where N is the total number of all facilities vertices. We give two examples to compare the proposed approach and two classical graph theoretic approaches. The results showed that the proposed connectivity graph possessed less vertices and edges, and the generation time of the proposed approach is also shorter than other two methods. Thus, the proposed approach can shorten the time of shortest distance calculation in detailed layout. Furthermore, the proposed graph can be valuable reference to the transport routing planning. [Copyright &y& Elsevier]

Abstract: Several protocols have been proposed to date to defend against wormhole attacks in wireless networks by adopting synchronized clocks, positioning devices, or directional antennas. These requirements and assumptions limit their applicability especially in the case of mobile networks where the degree of association and de-association between the nodes is relatively high. In this work, we present a novel lightweight countermeasure for the wormhole attack, called LDAC (Localized-Decentralized Algorithm for Countering wormholes). It is completely localized and works by looking for simple evidence that no attack is taking place, using only connectivity information, as implied by the underlying communication graph. LDAC is not confined to static networks but extends naturally to dynamic and even mobile ones. Rigorous arguments that prove the correctness of the algorithm are coupled with detailed performance evaluation along with an implementation on real sensor devices that demonstrates its efficiency in terms of memory requirements and processing overhead. [Copyright &y& Elsevier]

Location is important for most wireless sensor network applications. A potential localisation method uses a mobile beacon instead of numerous static beacons. This method includes planning a beacon trajectory as a fundamental and interesting problem. Obstacles in practical scenarios often restrict the free locomotion of beacons. This study examines the obstacle‐avoidance path‐planning method, which consists of three stages. First, the network deployment region is partitioned into cells by adaptive cell decomposition, and the corresponding connectivity graph is constructed. Second, a modified max–min ant system algorithm is provided to obtain the approximate shortest global path that covers the connectivity graph. Finally, a sequence of concentric circles of adjustable radii is utilised as the local path within an obstacle‐free cell. We prove that all sensor nodes deployed in obstacle‐free cells can be localised by using the proposed path. Simulation results show that more than 90% of the sensor nodes in the obstacle‐free region can be localised by using the given trajectory. [ABSTRACT FROM AUTHOR]

Abstract: Probability hypothesis density (PHD) filter and cardinalized PHD (CPHD) filter have proved to be promising algorithms for tracking an unknown number of targets in real time. However, they do not provide the identities of the individual estimated targets, so the target tracks cannot be obtained. To solve this problem, we propose a new track maintenance algorithm based on the cross entropy (CE) technique. Firstly, the particle filter PHD (PF-PHD) algorithm is used to estimate the target states and the target number. Then, the results of the estimation are used as vertexes to construct a connectivity graph with associated weights, and the CE technique is employed as a global optimization scheme to calculate the optimal feasible associated events. Furthermore, due to the advantages of the CPHD filter and the Rao-Blackwellized particle filter (RBPF), we propose another track maintenance algorithm based on the CE technique, named the RBPF–CPHD tracker, which can further improve the track maintenance performance due to the more accurate state estimates and their number estimates. Simulation results show that the proposed algorithms can effectively achieve the track continuity, with stronger robustness and greater anti-jamming capability. [Copyright &y& Elsevier]

Branching structure is a common feature of many natural objects. Given some mesh components with a branching shape missing, this paper presents a novel approach to fuse the mesh components: connectivity graph of the branching shape is constructed to seamlessly connect the boundaries of given components; then, natural geometry is imposed on the connectivity graph exploiting the information of given boundaries. We present a method to construct a branching connectivity graph to connect arbitrary number of given boundaries. Also, a method to generate natural geometry of the connectivity graph that smoothly fuses the boundaries of mesh components is exploited. Some examples are given to demonstrate that our new scheme can be used in a couple of applications, such as fast tree trunk modeling, mesh composition and shell generation. [ABSTRACT FROM AUTHOR]

The success in backbone resonance sequential assignment is fundamental to three dimensional protein structure determination via Nuclear Magnetic Resonance (NMR) spectroscopy. Such a sequential assignment can roughly be partitioned into three separate steps: grouping resonance peaks in multiple spectra into spin systems, chaining the resultant spin systems into strings, and assigning these strings to non-overlapping consecutive amino acid residues in the target protein. Separately dealing with these three steps has been adopted in many existing assignment programs, and it works well on protein NMR data with close-to-ideal quality, while only moderately or even poorly on most real protein datasets, where noises as well as data degeneracies occur frequently. We propose in this work to partition the sequential assignment not by physical steps, but only virtual steps, and use their outputs to cross validate each other. The novelty lies in the places, where the ambiguities at the grouping step will be resolved in finding the highly confident strings at the chaining step, and the ambiguities at the chaining step will be resolved by examining the mappings of strings at the assignment step. In this way, all ambiguities at the sequential assignment will be resolved globally and optimally. The resultant assignment program is called Graph-based Approach for Sequential Assignment (GASA), which has been compared to several recent similar developments including PACES, RANDOM, MARS, and RIBRA. The performance comparisons with these works demonstrated that GASA is more promising for practical use. [ABSTRACT FROM AUTHOR]

The aim of this letter is to determine the minimum node density to achieve a connected large-scale ad hoc network, where every node has the same transmitting and receiving capabilities. Due to the log-normal shadowing, links are unidirectional in general. Contrary to the prevailing opinion, we argue that such asymmetries result into a "reduced" connectivity graph, which, from the point of view of MAC and routing protocols, is to be considered the true or effective connectivity graph. Accordingly, we derive a new formula for the connection probability between two nodes in order to compute global connectivity. Finally, theoretical findings, borrowed from random graphs theory, are compared to numerical simulation results in synthetic wireless network scenarios. [ABSTRACT FROM PUBLISHER]

Performance of pulse-coupled distributed synchronization in wireless ad hoc networks is known to depend critically on the topology of the corresponding connectivity graph. This paper evaluates the impact of log-normal shadowing on the convergence of distributed discrete-time phase locked loops (PLLs). It is argued that the beneficial effect of shadowing on distributed synchronization can be seen as an instance of the "small-world" phenomenon. Evidence of this is further provided by evaluating average path length and clustering coefficient of the wireless network through simulations [ABSTRACT FROM PUBLISHER]

In this paper we propose a design procedure based on comprehensive integer linear programing (ILP) for translucent optical transport networks (OTNs), exploiting an extended version of the so-called “connectivity graph.” For the first time to the best of our knowledge, we propose a mathematical approach that covers the manifold challenges of a realistic optical layer OTN design, jointly solving the regenerator placement problem (RPP) and the routing, fiber and wavelength assignment with regenerator problem (RFWA-RP). As a first contribution, we extend the concept of the connectivity graph to a k-path (k-p) connectivity graph. Second, the formulation addresses the problem of planning the number of dense wavelength division multiplexing systems, jointly solving the RPP and placing transponders. Third, we consider regeneration devices as wavelength converters also, showing the benefits arising from that aspect disregarded in the existing impairment-aware (IA) ILP formulations based on the connectivity graph. Finally we compare over different networks the results of our design procedure with those achieved by a hybrid method that combines a simplified IA-ILP formulation with a greedy heuristic. Moreover, an analytical framework to evaluate the network cost in terms of capital expenditure and operational expenditure is also presented. We show that the k-p connectivity graph represents a cost-effective tool for network design, as it allows one to greatly reduce the number of resources needed in both the protected and the unprotected scenarios. [ABSTRACT FROM PUBLISHER]