Social Network Analysis

https://cyberleninka.org/article/n/854933.pdf

Social media analytics – Challenges in topic discovery, data collection, and data preparation

City Internet-of-Things (IoT) applications are becoming increasingly complicated and thus require large amounts of computational resources and strict latency requirements. Mobile cloud computing (MCC) is an effective way to alleviate the limitation of computation capacity by offloading complex tasks from mobile devices (MDs) to central clouds. Besides, mobile-edge computing (MEC) is a promising technology to reduce latency during data transmission and save energy by providing services in a timely manner. However, it is still difficult to solve the task offloading challenges in heterogeneous cloud computing environments, where edge clouds and central clouds work collaboratively to satisfy the requirements of city IoT applications. In this article, we consider the heterogeneity of edge and central cloud servers in the offloading destination selection. To jointly optimize the system utility and the bandwidth allocation for each MD, we establish a hybrid offloading model, including the collaboration of MCC and MEC. A distributed deep learning-driven task offloading (DDTO) algorithm is proposed to generate near-optimal offloading decisions over the MDs, edge cloud server, and central cloud server. Experimental results demonstrate the accuracy of the DDTO algorithm, which can effectively and efficiently generate near-optimal offloading decisions in the edge and cloud computing environments. Furthermore, it achieves high performance and greatly reduces the computational complexity when compared with other offloading schemes that neglect the collaboration of heterogeneous clouds. More precisely, the DDTO scheme can improve computational performance by 63%, compared with the local-only scheme.

Collaborate Edge and Cloud Computing With Distributed Deep Learning for Smart City Internet of Things

Autonomous mobile robots with lights

Detecting communities in dynamic evolving networks is of great interest It has received tremendous attention from researchers One promising solution is to update communities incrementally taking the historical information into consideration However, most of the existing methods are only suitable for the case of one node adding or one edge adding Factually, new data are always generated continuously with subgraphs joining simultaneously in dynamic evolving networks To address the above problem, we present an incremental method to detect communities by handling subgraphs We first make a comprehensive analysis and propose four types of incremental elements Then we propose different updating strategies Finally, we present the algorithms to detect communities incrementally in dynamic evolving networks The experimental results on real-world data sets indicate that the proposed method is effective and has superior performance compared with several widely used methods

An incremental method to detect communities in dynamic evolving social networks

In a seminal STOC'95 paper, Arya et al. conjectured that spanners for low-dimensional Euclidean spaces with constant maximum degree, hop-diameter O(logn) and lightness O(logn) (i.e., weight $O(\log n) \cdot w(\textsf{MST}))$ can be constructed in O(n logn) time. This conjecture, which became a central open question in this area, was resolved in the affirmative by Elkin and Solomon in STOC'13 (even for doubling metrics).

In this work we present a simpler construction of spanners for doubling metrics with the above guarantees. Moreover, our construction extends in a simple and natural way to provide k-fault tolerant spanners with maximum degree O(k2), hop-diameter O(logn) and lightness O(k2 logn).

/pdf/new-doubling-spanners-better-and-simpler-3cb8bf1k1r.pdf

New doubling spanners: better and simpler

This paper presents the first distributed algorithm to construct a spanner for arbitrary ad hoc networks under the physical signal-to-interference-and-noise-ratio (SINR) interference model. Spanner construction is one of the most important techniques for topology control in wireless networks, which intends to find a sparse topology in which only a small number of links need to be maintained, without substantially degrading the path connecting any pair of the nodes in the network. Due to the non-local property of interference, constructing a spanner is challenging under the SINR model, especially when a local distributed algorithm is desired. We meet this challenge by proposing an efficient randomized distributed algorithm that can construct a spanner in $O(\log n\log \Gamma )$ timeslots with a high probability, where $n$ is the total number of nodes and $\Gamma $ describes the ratio of the maximum distance to the minimum distance between nodes. The constructed spanner concurrently satisfies two most desirable properties: constant stretch and linear sparseness. Our algorithm employs a novel maximal independent set (MIS) procedure as a subroutine, which is crucial in achieving the time efficiency of spanner construction. The MIS algorithm improves the best known result of $O(\log ^{2}n)$ [33] to $O(\log n)$ and is of independent interest as the algorithm is applicable also to many other applications. We conduct simulations to verify the proposed spanner construction algorithm, and the results show that our algorithm also performs well in realistic environments.

Distributed Spanner Construction With Physical Interference: Constant Stretch and Linear Sparseness

In a seminal STOC 1995 paper, Arya et al. conjectured that spanners for low-dimensional Euclidean spaces with constant maximum degree, hop-diameter $O(\log n)$, and lightness $O(\log n)$ (i.e., weight $O(\log n) \cdot w({MST}))$ can be constructed in $O(n \log n)$ time. This conjecture, which became a central open question in this area, was resolved in the affirmative by Elkin and Solomon in STOC 2013. In fact, Elkin and Solomon proved that the conjecture of Arya et al. holds even in doubling metrics. However, Elkin and Solomon's spanner construction is complicated. In this work we present a significantly simpler construction of spanners for doubling metrics with the same guarantees as above. Our construction is based on the basic net-tree spanner framework. However, by employing well-known properties of the net-tree spanner in conjunction with numerous new ideas, we managed to get significantly stronger results. First and foremost, our construction extends in a simple and natural way to provide $k$-fault tolerant spanners with maximum degree $O(k^2)$, hop-diameter $O(\log n)$, and lightness $O(k^2 \log n)$. This is the first construction of fault-tolerant spanners (even for Euclidean metrics) that achieves good bounds (polylogarithmic in $n$ and polynomial in $k$) on all the involved parameters simultaneously. Second, we show that the lightness bound of our construction can be improved to $O(k^2)$ (with high probability), for random points in $[0,1]^D$, where $2 \le D = O(1)$.

/pdf/new-doubling-spanners-32d8ls6x7e.pdf

New Doubling Spanners

We consider vertex-labeled graphs, where each vertex v is attached with a label from a set of labels. The vertex-to-label distance query desires the length of the shortest path from the given vertex to the set of vertices with the given label. We show how to construct an oracle for a vertex-labeled planar graph, such that $O(\frac{1}{\epsilon}n\log n)$ storing space is needed, and any vertex-to-label query can be answered in $O(\frac{1}{\epsilon}\log n\log \Delta)$ time with stretch 1 + e. Here, Δ is the hop-diameter of the given graph. For the case that Δ = O(logn), we construct a distance oracle that achieves $O(\frac{1}{\epsilon}\log n)$ query time, without changing space usage.

(1 + ε)-Distance Oracles for Vertex-Labeled Planar Graphs

Recently Elkin and Solomon gave a construction of spanners for doubling metrics that has constant maximum degree, hop-diameter O(log n) and lightness O(log n) (i.e., weight O(log n)w(MST). This resolves a long standing conjecture proposed by Arya et al. in a seminal STOC 1995 paper. 
However, Elkin and Solomon's spanner construction is extremely complicated; we offer a simple alternative construction that is very intuitive and is based on the standard technique of net tree with cross edges. Indeed, our approach can be readily applied to our previous construction of k-fault tolerant spanners (ICALP 2012) to achieve k-fault tolerance, maximum degree O(k^2), hop-diameter O(log n) and lightness O(k^3 log n).

Li Ning

Papers

New doubling spanners: better and simpler

Distributed Spanner Construction With Physical Interference: Constant Stretch and Linear Sparseness

New Doubling Spanners

(1 + ε)-Distance Oracles for Vertex-Labeled Planar Graphs

Incubators vs Zombies: Fault-Tolerant, Short, Thin and Lanky Spanners for Doubling Metrics