Symmetry

3711 KiB

Open AccessArticle

A Design for Genetically Oriented Rules-Based Incremental Granular Models and Its Application

by Yeong-Hyeon Byeon and Keun-Chang Kwak

Symmetry 2017, 9(12), 324; https://doi.org/10.3390/sym9120324 - 20 Dec 2017

Cited by 3 | Viewed by 2989

In this paper, we develop a genetically oriented rule-based Incremental Granular Model (IGM). The IGM is designed using a combination of a simple Linear Regression (LR) model and a local Linguistic Model (LM) to predict the modeling error obtained by the LR. The [...] Read more.

In this paper, we develop a genetically oriented rule-based Incremental Granular Model (IGM). The IGM is designed using a combination of a simple Linear Regression (LR) model and a local Linguistic Model (LM) to predict the modeling error obtained by the LR. The IGM has been successfully applied to various examples. However, the disadvantage of IGM is that the number of clusters in each context is determined, with the same number, by trial and error. Moreover, a weighting exponent is set to the typical value. In order to solve these problems, the goal of this paper is to design an optimized rule-based IGM with the use of a Genetic Algorithm (GA) to simultaneously optimize the number of cluster centers in each context, the number of contexts, and the weighting exponent. The experimental results regarding a coagulant dosing process in a water purification plant, an automobile mpg (miles per gallon) prediction, and a Boston housing data set revealed that the proposed GA-based IGM showed good performance, when compared with the Radial Basis Function Neural Network (RBFNN), LM, Takagi–Sugeno–Kang (TSK)-Linguistic Fuzzy Model (LFM), GA-based LM, and IGM itself. Full article

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251 KiB

Open AccessFeature PaperArticle

Boundary Value Problems for Some Important Classes of Recurrent Relations with Two Independent Variables

by Stevo Stević, Bratislav Iričanin and Zdeněk Šmarda

Symmetry 2017, 9(12), 323; https://doi.org/10.3390/sym9120323 - 20 Dec 2017

Cited by 3 | Viewed by 2791

Abstract

It is shown that complex-valued boundary value problems for several classes of recurrent relations with two independent variables, of some considerable interest, are solvable on the following domain: [...] Read more.

It is shown that complex-valued boundary value problems for several classes of recurrent relations with two independent variables, of some considerable interest, are solvable on the following domain:

C = {(n, k) : 0 \leq k \leq n, k \in N_{0}, n \in N}

, the so called combinatorial domain. The recurrent relations include some of the most important combinatorial ones, which, among other things, serve as a motivation for the investigation. The methods for solving the boundary value problems are presented and explained in detail. Full article

(This article belongs to the Special Issue Symmetry: Feature Papers 2017)

5843 KiB

Open AccessArticle

Graph Cellular Automata with Relation-Based Neighbourhoods of Cells for Complex Systems Modelling: A Case of Traffic Simulation

by Krzysztof Małecki

Symmetry 2017, 9(12), 322; https://doi.org/10.3390/sym9120322 - 19 Dec 2017

Cited by 29 | Viewed by 6481

Abstract

A complex system is a set of mutually interacting elements for which it is possible to construct a mathematical model. This article focuses on the cellular automata theory and the graph theory in order to compare various types of cellular automata and to [...] Read more.

A complex system is a set of mutually interacting elements for which it is possible to construct a mathematical model. This article focuses on the cellular automata theory and the graph theory in order to compare various types of cellular automata and to analyse applications of graph structures together with cellular automata. It proposes a graph cellular automaton with a variable configuration of cells and relation-based neighbourhoods (r–GCA). The developed mechanism enables modelling of phenomena found in complex systems (e.g., transport networks, urban logistics, social networks) taking into account the interaction between the existing objects. As an implementation example, modelling of moving vehicles has been made and r–GCA was compared to the other cellular automata models simulating the road traffic and used in the computer simulation process. Full article

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7571 KiB

Open AccessArticle

A Novel String Grammar Unsupervised Possibilistic C-Medians Algorithm for Sign Language Translation Systems

by Atcharin Klomsae, Sansanee Auephanwiriyakul and Nipon Theera-Umpon

Symmetry 2017, 9(12), 321; https://doi.org/10.3390/sym9120321 - 19 Dec 2017

Cited by 7 | Viewed by 4636

Abstract

Sign language is a basic method for solving communication problems between deaf and hearing people. In order to communicate, deaf and hearing people normally use hand gestures, which include a combination of hand positioning, hand shapes, and hand movements. Thai Sign Language is [...] Read more.

Sign language is a basic method for solving communication problems between deaf and hearing people. In order to communicate, deaf and hearing people normally use hand gestures, which include a combination of hand positioning, hand shapes, and hand movements. Thai Sign Language is the communication method for Thai hearing-impaired people. Our objective is to improve the dynamic Thai Sign Language translation method with a video captioning technique that does not require prior hand region detection and segmentation through using the Scale Invariant Feature Transform (SIFT) method and the String Grammar Unsupervised Possibilistic C-Medians (sgUPCMed) algorithm. This work is the first to propose the sgUPCMed algorithm to cope with the unsupervised generation of multiple prototypes in the possibilistic sense for string data. In our experiments, the Thai Sign Language data set (10 isolated sign language words) was collected from 25 subjects. The best average result within the constrained environment of the blind test data sets of signer-dependent cases was 89–91%, and the successful rate of signer semi-independent cases was 81–85%, on average. For the blind test data sets of signer-independent cases, the best average classification rate was 77–80%. The average result of the system without a constrained environment was around 62–80% for the signer-independent experiments. To show that the proposed algorithm can be implemented in other sign languages, the American sign language (RWTH-BOSTON-50) data set, which consists of 31 isolated American Sign Language words, is also used in the experiment. The system provides 88.56% and 91.35% results on the validation set alone, and for both the training and validation sets, respectively. Full article

(This article belongs to the Special Issue Emerging Approaches and Advances in Big Data)

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291 KiB

Open AccessArticle

Probabilistic Linguistic Power Aggregation Operators for Multi-Criteria Group Decision Making

by Agbodah Kobina, Decui Liang and Xin He

Symmetry 2017, 9(12), 320; https://doi.org/10.3390/sym9120320 - 19 Dec 2017

Cited by 61 | Viewed by 4227

Abstract

As an effective aggregation tool, power average (PA) allows the input arguments being aggregated to support and reinforce each other, which provides more versatility in the information aggregation process. Under the probabilistic linguistic term environment, we deeply investigate the new power aggregation (PA) [...] Read more.

As an effective aggregation tool, power average (PA) allows the input arguments being aggregated to support and reinforce each other, which provides more versatility in the information aggregation process. Under the probabilistic linguistic term environment, we deeply investigate the new power aggregation (PA) operators for fusing the probabilistic linguistic term sets (PLTSs). In this paper, we firstly develop the probabilistic linguistic power average (PLPA), the weighted probabilistic linguistic power average (WPLPA) operators, the probabilistic linguistic power geometric (PLPG) and the weighted probabilistic linguistic power geometric (WPLPG) operators. At the same time, we carefully analyze the properties of these new aggregation operators. With the aid of the WPLPA and WPLPG operators, we further design the approaches for the application of multi-criteria group decision-making (MCGDM) with PLTSs. Finally, we use an illustrated example to expound our proposed methods and verify their performances. Full article

(This article belongs to the Special Issue Fuzzy Techniques for Decision Making)

386 KiB

Open AccessArticle

New Applications of m-Polar Fuzzy Matroids

by Musavarah Sarwar and Muhammad Akram

Symmetry 2017, 9(12), 319; https://doi.org/10.3390/sym9120319 - 18 Dec 2017

Cited by 26 | Viewed by 4083

Abstract

Mathematical modelling is an important aspect in apprehending discrete and continuous physical systems. Multipolar uncertainty in data and information incorporates a significant role in various abstract and applied mathematical modelling and decision analysis. Graphical and algebraic models can be studied more precisely when [...] Read more.

Mathematical modelling is an important aspect in apprehending discrete and continuous physical systems. Multipolar uncertainty in data and information incorporates a significant role in various abstract and applied mathematical modelling and decision analysis. Graphical and algebraic models can be studied more precisely when multiple linguistic properties are dealt with, emphasizing the need for a multi-index, multi-object, multi-agent, multi-attribute and multi-polar mathematical approach. An m-polar fuzzy set is introduced to overcome the limitations entailed in single-valued and two-valued uncertainty. Our aim in this research study is to apply the powerful methodology of m-polar fuzzy sets to generalize the theory of matroids. We introduce the notion of m-polar fuzzy matroids and investigate certain properties of various types of m-polar fuzzy matroids. Moreover, we apply the notion of the m-polar fuzzy matroid to graph theory and linear algebra. We present m-polar fuzzy circuits, closures of m-polar fuzzy matroids and put special emphasis on m-polar fuzzy rank functions. Finally, we also describe certain applications of m-polar fuzzy matroids in decision support systems, ordering of machines and network analysis. Full article

(This article belongs to the Special Issue Fuzzy Techniques for Decision Making)

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279 KiB

Open AccessArticle

Algebraic Aspects of the Supersymmetric Minimal Surface Equation

by Alfred Michel Grundland and Alexander Hariton

Symmetry 2017, 9(12), 318; https://doi.org/10.3390/sym9120318 - 18 Dec 2017

Cited by 5 | Viewed by 2403

Abstract

In this paper, a supersymmetric extension of the minimal surface equation is formulated. Based on this formulation, a Lie superalgebra of infinitesimal symmetries of this equation is determined. A classification of the one-dimensional subalgebras is performed, which results in a list of 143 [...] Read more.

In this paper, a supersymmetric extension of the minimal surface equation is formulated. Based on this formulation, a Lie superalgebra of infinitesimal symmetries of this equation is determined. A classification of the one-dimensional subalgebras is performed, which results in a list of 143 conjugacy classes with respect to action by the supergroup generated by the Lie superalgebra. The symmetry reduction method is used to obtain invariant solutions of the supersymmetric minimal surface equation. The classical minimal surface equation is also examined and its group-theoretical properties are compared with those of the supersymmetric version. Full article

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Open AccessArticle

Analyzing Spatial Behavior of Backcountry Skiers in Mountain Protected Areas Combining GPS Tracking and Graph Theory

by Karolina Taczanowska, Mikołaj Bielański, Luis-Millán González, Xavier Garcia-Massó and José L. Toca-Herrera

Symmetry 2017, 9(12), 317; https://doi.org/10.3390/sym9120317 - 14 Dec 2017

Cited by 22 | Viewed by 5884

Abstract

Mountain protected areas (PAs) aim to preserve vulnerable environments and at the same time encourage numerous outdoor leisure activities. Understanding the way people use natural environments is crucial to balance the needs of visitors and site capacities. This study aims to develop an [...] Read more.

Mountain protected areas (PAs) aim to preserve vulnerable environments and at the same time encourage numerous outdoor leisure activities. Understanding the way people use natural environments is crucial to balance the needs of visitors and site capacities. This study aims to develop an approach to evaluate the structure and use of designated skiing zones in PAs combining Global Positioning System (GPS) tracking and analytical methods based on graph theory. The study is based on empirical data (n = 609 GPS tracks of backcountry skiers) collected in Tatra National Park (TNP), Poland. The physical structure of the entire skiing zones system has been simplified into a graph structure (structural network; undirected graph). In a second step, the actual use of the area by skiers (functional network; directed graph) was analyzed using a graph-theoretic approach. Network coherence (connectivity indices: β, γ, α), movement directions at path segments, and relative importance of network nodes (node centrality measures: degree, betweenness, closeness, and proximity prestige) were calculated. The system of designated backcountry skiing zones was not evenly used by the visitors. Therefore, the calculated parameters differ significantly between the structural and the functional network. In particular, measures related to the actually used trails are of high importance from the management point of view. Information about the most important node locations can be used for planning sign-posts, on-site maps, interpretative boards, or other tourist infrastructure. Full article

(This article belongs to the Special Issue Graph Theory)

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17433 KiB

Open AccessArticle

Tangible Visualization Table for Intuitive Data Display

by Jongyong Kim, Cheongun Lee, Seung-Hyun Yoon and Sanghun Park

Symmetry 2017, 9(12), 316; https://doi.org/10.3390/sym9120316 - 13 Dec 2017

Viewed by 4513

Abstract

We propose a new tangible visualization table for intuitive and effective visualization of terrain data transferred from a remote server in real time. The shape display approximating the height field of remote terrain data is generated by linear actuators, and the corresponding texture [...] Read more.

We propose a new tangible visualization table for intuitive and effective visualization of terrain data transferred from a remote server in real time. The shape display approximating the height field of remote terrain data is generated by linear actuators, and the corresponding texture image is projected onto the shape display. To minimize projection distortions, we present a sophisticated technique for projection mapping. Gesture-based user interfaces facilitate intuitive manipulations of visualization results. We demonstrate the effectiveness of our system by displaying and manipulating various terrain data using gesture-based interfaces. Full article

(This article belongs to the Special Issue Advances in Computer Graphics, Geometric Modeling, and Virtual and Augmented Reality)

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Open AccessFeature PaperArticle

Knotoids, Braidoids and Applications

by Neslihan Gügümcü and Sofia Lambropoulou

Symmetry 2017, 9(12), 315; https://doi.org/10.3390/sym9120315 - 12 Dec 2017

Cited by 17 | Viewed by 3962

Abstract

This paper is an introduction to the theory of braidoids. Braidoids are geometric objects analogous to classical braids, forming a counterpart theory to the theory of knotoids. We introduce these objects and their topological equivalences, and we conclude with a potential application to [...] Read more.

This paper is an introduction to the theory of braidoids. Braidoids are geometric objects analogous to classical braids, forming a counterpart theory to the theory of knotoids. We introduce these objects and their topological equivalences, and we conclude with a potential application to the study of proteins. Full article

(This article belongs to the Special Issue Knot Theory and Its Applications)

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203 KiB

Open AccessFeature PaperArticle

The Exact Evaluation of Some New Lattice Sums

by I. J. Zucker

Symmetry 2017, 9(12), 314; https://doi.org/10.3390/sym9120314 - 11 Dec 2017

Cited by 6 | Viewed by 3040

Abstract

New q-series in the spirit of Jacobi have been found in a publication first published in 1884 written in Russian and translated into English in 1928. This work was found by chance and appears to be almost totally unknown. From these entirely [...] Read more.

New q-series in the spirit of Jacobi have been found in a publication first published in 1884 written in Russian and translated into English in 1928. This work was found by chance and appears to be almost totally unknown. From these entirely new q-series, fresh lattice sums have been discovered and are presented here. Full article

(This article belongs to the Special Issue Mathematical Crystallography)

2527 KiB

Open AccessArticle

Detection of Double-Compressed H.264/AVC Video Incorporating the Features of the String of Data Bits and Skip Macroblocks

by Heng Yao, Saihua Song, Chuan Qin, Zhenjun Tang and Xiaokai Liu

Symmetry 2017, 9(12), 313; https://doi.org/10.3390/sym9120313 - 11 Dec 2017

Cited by 16 | Viewed by 5033

Abstract

Today’s H.264/AVC coded videos have a high quality, high data-compression ratio. They also have a strong fault tolerance, better network adaptability, and have been widely applied on the Internet. With the popularity of powerful and easy-to-use video editing software, digital videos can be [...] Read more.

Today’s H.264/AVC coded videos have a high quality, high data-compression ratio. They also have a strong fault tolerance, better network adaptability, and have been widely applied on the Internet. With the popularity of powerful and easy-to-use video editing software, digital videos can be tampered with in various ways. Therefore, the double compression in the H.264/AVC video can be used as a first step in the study of video-tampering forensics. This paper proposes a simple, but effective, double-compression detection method that analyzes the periodic features of the string of data bits (SODBs) and the skip macroblocks (S-MBs) for all I-frames and P-frames in a double-compressed H.264/AVC video. For a given suspicious video, the SODBs and S-MBs are extracted for each frame. Both features are then incorporated to generate one enhanced feature to represent the periodic artifact of the double-compressed video. Finally, a time-domain analysis is conducted to detect the periodicity of the features. The primary Group of Pictures (GOP) size is estimated based on an exhaustive strategy. The experimental results demonstrate the efficacy of the proposed method. Full article

(This article belongs to the Special Issue Information Technology and Its Applications)

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3189 KiB

Open AccessArticle

Chaotic Dynamical State Variables Selection Procedure Based Image Encryption Scheme

by Zia Bashir, Jarosław Wątróbski, Tabasam Rashid, Sohail Zafar and Wojciech Sałabun

Symmetry 2017, 9(12), 312; https://doi.org/10.3390/sym9120312 - 11 Dec 2017

Cited by 17 | Viewed by 4065

Abstract

Nowadays, in the modern digital era, the use of computer technologies such as smartphones, tablets and the Internet, as well as the enormous quantity of confidential information being converted into digital form have resulted in raised security issues. This, in turn, has led [...] Read more.

Nowadays, in the modern digital era, the use of computer technologies such as smartphones, tablets and the Internet, as well as the enormous quantity of confidential information being converted into digital form have resulted in raised security issues. This, in turn, has led to rapid developments in cryptography, due to the imminent need for system security. Low-dimensional chaotic systems have low complexity and key space, yet they achieve high encryption speed. An image encryption scheme is proposed that, without compromising the security, uses reasonable resources. We introduced a chaotic dynamic state variables selection procedure (CDSVSP) to use all state variables of a hyper-chaotic four-dimensional dynamical system. As a result, less iterations of the dynamical system are required, and resources are saved, thus making the algorithm fast and suitable for practical use. The simulation results of security and other miscellaneous tests demonstrate that the suggested algorithm excels at robustness, security and high speed encryption. Full article

(This article belongs to the Special Issue Emerging Data Hiding Systems in Image Communications)

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1911 KiB

Open AccessArticle

Task-Management Method Using R-Tree Spatial Cloaking for Large-Scale Crowdsourcing

by Yan Li and Byeong-Seok Shin

Symmetry 2017, 9(12), 311; https://doi.org/10.3390/sym9120311 - 10 Dec 2017

Cited by 4 | Viewed by 3788

Abstract

With the development of sensor technology and the popularization of the data-driven service paradigm, spatial crowdsourcing systems have become an important way of collecting map-based location data. However, large-scale task management and location privacy are important factors for participants in spatial crowdsourcing. In [...] Read more.

With the development of sensor technology and the popularization of the data-driven service paradigm, spatial crowdsourcing systems have become an important way of collecting map-based location data. However, large-scale task management and location privacy are important factors for participants in spatial crowdsourcing. In this paper, we propose the use of an R-tree spatial cloaking-based task-assignment method for large-scale spatial crowdsourcing. We use an estimated R-tree based on the requested crowdsourcing tasks to reduce the crowdsourcing server-side inserting cost and enable the scalability. By using Minimum Bounding Rectangle (MBR)-based spatial anonymous data without exact position data, this method preserves the location privacy of participants in a simple way. In our experiment, we showed that our proposed method is faster than the current method, and is very efficient when the scale is increased. Full article

(This article belongs to the Special Issue Advanced in Artificial Intelligence and Cloud Computing)

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3495 KiB

Open AccessArticle

Reconstructing Damaged Complex Networks Based on Neural Networks

by Ye Hoon Lee and Insoo Sohn

Symmetry 2017, 9(12), 310; https://doi.org/10.3390/sym9120310 - 09 Dec 2017

Cited by 9 | Viewed by 3620

Abstract

Despite recent progress in the study of complex systems, reconstruction of damaged networks due to random and targeted attack has not been addressed before. In this paper, we formulate the network reconstruction problem as an identification of network structure based on much reduced [...] Read more.

Despite recent progress in the study of complex systems, reconstruction of damaged networks due to random and targeted attack has not been addressed before. In this paper, we formulate the network reconstruction problem as an identification of network structure based on much reduced link information. Furthermore, a novel method based on multilayer perceptron neural network is proposed as a solution to the problem of network reconstruction. Based on simulation results, it was demonstrated that the proposed scheme achieves very high reconstruction accuracy in small-world network model and a robust performance in scale-free network model. Full article

(This article belongs to the Special Issue Graph Theory)

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3339 KiB

Open AccessArticle

Graphical Classification in Multi-Centrality-Index Diagrams for Complex Chemical Networks

by Yasutaka Mizui, Tetsuya Kojima, Shigeyuki Miyagi and Osamu Sakai

Symmetry 2017, 9(12), 309; https://doi.org/10.3390/sym9120309 - 09 Dec 2017

Cited by 18 | Viewed by 4709

Abstract

Various sizes of chemical reaction network exist, from small graphs of linear networks with several inorganic species to huge complex networks composed of protein reactions or metabolic systems. Huge complex networks of organic substrates have been well studied using statistical properties such as [...] Read more.

Various sizes of chemical reaction network exist, from small graphs of linear networks with several inorganic species to huge complex networks composed of protein reactions or metabolic systems. Huge complex networks of organic substrates have been well studied using statistical properties such as degree distributions. However, when the size is relatively small, statistical data suffers from significant errors coming from irregular effects by species, and a macroscopic analysis is frequently unsuccessful. In this study, we demonstrate a graphical classification method for chemical networks that contain tens of species. Betweenness and closeness centrality indices of a graph can create a two-dimensional diagram with information of node distribution for a complex chemical network. This diagram successfully reveals systematic sharing of roles among species as a semi-statistical property in chemical reactions, and distinguishes it from the ones in random networks, which has no functional node distributions. This analytical approach is applicable for rapid and approximate understanding of complex chemical network systems such as plasma-enhanced reactions as well as visualization and classification of other graphs. Full article

(This article belongs to the Special Issue Graph Theory)

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Open AccessArticle

A Block-Based Division Reversible Data Hiding Method in Encrypted Images

by Wei-Liang Liu, Hui-Shih Leng, Chuan-Kuei Huang and Dyi-Cheng Chen

Symmetry 2017, 9(12), 308; https://doi.org/10.3390/sym9120308 - 08 Dec 2017

Cited by 10 | Viewed by 4211

Abstract

Due to the increased digital media on the Internet, data security and privacy protection issue have attracted the attention of data communication. Data hiding has become a topic of considerable importance. Nowadays, a new challenge consists of reversible data hiding in the encrypted [...] Read more.

Due to the increased digital media on the Internet, data security and privacy protection issue have attracted the attention of data communication. Data hiding has become a topic of considerable importance. Nowadays, a new challenge consists of reversible data hiding in the encrypted image because of the correlations of local pixels that are destroyed in an encrypted image; it is difficult to embed secret messages in encrypted images using the difference of neighboring pixels. In this paper, the proposed method uses a block-based division mask and a new encrypted method based on the logistic map and an additive homomorphism to embed data in an encrypted image by histogram shifting technique. Our experimental results show that the proposed method achieves a higher payload than other works and is more immune to attack upon the cryptosystem. Full article

(This article belongs to the Special Issue Information Technology and Its Applications)

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Open AccessArticle

A Secure Mobility Network Authentication Scheme Ensuring User Anonymity

by Ya-Fen Chang, Wei-Liang Tai and Min-How Hsu

Symmetry 2017, 9(12), 307; https://doi.org/10.3390/sym9120307 - 08 Dec 2017

Cited by 5 | Viewed by 3406

Abstract

With the rapid growth of network technologies, users are used to accessing various services with their mobile devices. To ensure security and privacy in mobility networks, proper mechanisms to authenticate the mobile user are essential. In this paper, a mobility network authentication scheme [...] Read more.

With the rapid growth of network technologies, users are used to accessing various services with their mobile devices. To ensure security and privacy in mobility networks, proper mechanisms to authenticate the mobile user are essential. In this paper, a mobility network authentication scheme based on elliptic curve cryptography is proposed. In the proposed scheme, a mobile user can be authenticated without revealing who he is for user anonymity, and a session key is also negotiated to protect the following communications. The proposed mobility network authentication scheme is analyzed to show that it can ensure security, user anonymity, and convenience. Moreover, Burrows-Abadi-Needham logic (BAN logic) is used to deduce the completeness of the proposed authentication scheme. Full article

(This article belongs to the Special Issue Information Technology and Its Applications)

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Open AccessArticle

Complexity Phenomena Induced by Novel Symmetry and Symmetry-Breakings with Antiscreening at Cosmological Scales—A Tutorial

by Tom T. S. Chang

Symmetry 2017, 9(12), 306; https://doi.org/10.3390/sym9120306 - 07 Dec 2017

Cited by 1 | Viewed by 2717

Abstract

Complexity phenomena in cosmological evolution due to the scale-running of the propagator coupling constant can yield new insights related to virtual particles and antiscreening effects with dark matter consequences. This idea was developed in accordance with the differential-integral functional formulation of the Wilsonian [...] Read more.

Complexity phenomena in cosmological evolution due to the scale-running of the propagator coupling constant can yield new insights related to virtual particles and antiscreening effects with dark matter consequences. This idea was developed in accordance with the differential-integral functional formulation of the Wilsonian renormalization group based on the one-particle irreducible scale-dependent effective action for gravitational evolution. In this tutorial communication, we briefly describe the essence of the result with minimal mathematical details and then consider a few simple examples to provide a basic understanding of such an interesting and intriguing complexity process in terms of fractional calculus. Full article

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Open AccessArticle

Face Liveness Detection Based on Skin Blood Flow Analysis

by Shun-Yi Wang, Shih-Hung Yang, Yon-Ping Chen and Jyun-We Huang

Symmetry 2017, 9(12), 305; https://doi.org/10.3390/sym9120305 - 07 Dec 2017

Cited by 24 | Viewed by 10745

Abstract

Face recognition systems have been widely adopted for user authentication in security systems due to their simplicity and effectiveness. However, spoofing attacks, including printed photos, displayed photos, and replayed video attacks, are critical challenges to authentication, and these spoofing attacks allow malicious invaders [...] Read more.

Face recognition systems have been widely adopted for user authentication in security systems due to their simplicity and effectiveness. However, spoofing attacks, including printed photos, displayed photos, and replayed video attacks, are critical challenges to authentication, and these spoofing attacks allow malicious invaders to gain access to the system. This paper proposes two novel features for face liveness detection systems to protect against printed photo attacks and replayed attacks for biometric authentication systems. The first feature obtains the texture difference between red and green channels of face images inspired by the observation that skin blood flow in the face has properties that enable distinction between live and spoofing face images. The second feature estimates the color distribution in the local regions of face images, instead of whole images, because image quality might be more discriminative in small areas of face images. These two features are concatenated together, along with a multi-scale local binary pattern feature, and a support vector machine classifier is trained to discriminate between live and spoofing face images. The experimental results show that the performance of the proposed method for face spoof detection is promising when compared with that of previously published methods. Furthermore, the proposed system can be implemented in real time, which is valuable for mobile applications. Full article

(This article belongs to the Special Issue Information Technology and Its Applications)

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Open AccessArticle

Performance Analysis of MIMO System with Single RF Link Based on Switched Parasitic Antenna

by He Yu, Guohui Yang, Fanyi Meng and Yingsong Li

Symmetry 2017, 9(12), 304; https://doi.org/10.3390/sym9120304 - 06 Dec 2017

Cited by 7 | Viewed by 4651

Abstract

This paper introduces the principle and key technology of single radio frequency (RF) link Multiple-Input Multiple-Output (MIMO) system based on a switched parasitic antenna (SPA). The software SystemVue is adopted for signal processing and system-level simulation with merit of strong operability and high [...] Read more.

This paper introduces the principle and key technology of single radio frequency (RF) link Multiple-Input Multiple-Output (MIMO) system based on a switched parasitic antenna (SPA). The software SystemVue is adopted for signal processing and system-level simulation with merit of strong operability and high efficiency, which provides tools for the single RF link MIMO system research. A single RF link of a 2 × 2 MIMO system based on the switch parasitic antenna is proposed in this paper. The binary codes are modulated to the baseband Binary Phase Shift Keying (BPSK) signals and transmitted with a 2.4 GHz carrier frequency. The receiver based on the super-heterodyne prototype adopts the channel equalization algorithm for restoring symbols, and it can effectively reduce the system error rate. The simulation results show that the MIMO system built on the platform can achieve equivalent performance with traditional MIMO system, which validates the effectiveness of the proposed scheme. The switched parasitic antenna and equalization algorithm provide new research ideas for single RF link MIMO system and have theoretical significance for further research. Full article

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Open AccessArticle

Determinant Formulae of Matrices with Certain Symmetry and Its Applications

by Yongju Bae and In Sook Lee

Symmetry 2017, 9(12), 303; https://doi.org/10.3390/sym9120303 - 06 Dec 2017

Cited by 2 | Viewed by 3792

Abstract

In this paper, we introduce formulae for the determinants of matrices with certain symmetry. As applications, we will study the Alexander polynomial and the determinant of a periodic link which is presented as the closure of an oriented 4-tangle. Full article

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Open AccessArticle

Internet of Things: A Scientometric Review

by Juan Ruiz-Rosero, Gustavo Ramirez-Gonzalez, Jennifer M. Williams, Huaping Liu, Rahul Khanna and Greeshma Pisharody

Symmetry 2017, 9(12), 301; https://doi.org/10.3390/sym9120301 - 06 Dec 2017

Cited by 49 | Viewed by 10382

Abstract

Internet of Things (IoT) is connecting billions of devices to the Internet. These IoT devices chain sensing, computation, and communication techniques, which facilitates remote data collection and analysis. wireless sensor networks (WSN) connect sensing devices together on a local network, thereby eliminating wires, [...] Read more.

Internet of Things (IoT) is connecting billions of devices to the Internet. These IoT devices chain sensing, computation, and communication techniques, which facilitates remote data collection and analysis. wireless sensor networks (WSN) connect sensing devices together on a local network, thereby eliminating wires, which generate a large number of samples, creating a big data challenge. This IoT paradigm has gained traction in recent years, yielding extensive research from an increasing variety of perspectives, including scientific reviews. These reviews cover surveys related to IoT vision, enabling technologies, applications, key features, co-word and cluster analysis, and future directions. Nevertheless, we lack an IoT scientometrics review that uses scientific databases to perform a quantitative analysis. This paper develops a scientometric review about IoT over a data set of 19,035 documents published over a period of 15 years (2002–2016) in two main scientific databases (Clarivate Web of Science and Scopus). A Python script called ScientoPy was developed to perform quantitative analysis of this data set. This provides insight into research trends by investigating a lead author’s country affiliation, most published authors, top research applications, communication protocols, software processing, hardware, operating systems, and trending topics. Furthermore, we evaluate the top trending IoT topics and the popular hardware and software platforms that are used to research these trends. Full article

(This article belongs to the Special Issue Applications of Internet of Things)

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Open AccessArticle

A Study for Parametric Morphogeometric Operators to Assist the Detection of Keratoconus

by Laurent Bataille, Francisco Cavas-Martínez, Daniel G. Fernández-Pacheco, Francisco J. F. Cañavate and Jorge L. Alio

Symmetry 2017, 9(12), 302; https://doi.org/10.3390/sym9120302 - 05 Dec 2017

Cited by 3 | Viewed by 4414

Abstract

The aim of this study is to describe a new keratoconus detection method based on the analysis of certain parametric morphogeometric operators extracted from a custom patient-specific three-dimensional (3D) model of the human cornea. A corneal geometric reconstruction is firstly performed using zonal [...] Read more.

The aim of this study is to describe a new keratoconus detection method based on the analysis of certain parametric morphogeometric operators extracted from a custom patient-specific three-dimensional (3D) model of the human cornea. A corneal geometric reconstruction is firstly performed using zonal functions and retrospective Scheimpflug tomography data from 107 eyes of 107 patients. The posterior corneal surface is later analysed using an optimised computational geometry technique and the morphology of healthy and keratoconic corneas is characterized by means of geometric variables. The performance of these variables as predictors of a new geometric marker is assessed through a receiver operating characteristic (ROC) curve analysis and their correlations are analysed through Pearson or Spearman coefficients. The posterior apex deviation variable shows the best keratoconus diagnosis capability. However, the strongest correlations in both healthy and pathological corneas are provided by the metrics directly related to the thickness as the sagittal plane area at the apex and the sagittal plane area at the minimum thickness point. A comparison of the screening of keratoconus provided by the Sirius topographer and the detection of corneal ectasia using the posterior apex deviation parameter is also performed, demonstrating the accuracy of this characterization as an effective marker of the diagnosis and ectatic disease progression. Full article

(This article belongs to the Special Issue Advances in Computer Graphics, Geometric Modeling, and Virtual and Augmented Reality)

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Open AccessArticle

Cohomology Characterizations of Diagonal Non-Abelian Extensions of Regular Hom-Lie Algebras

by Lina Song and Rong Tang

Symmetry 2017, 9(12), 297; https://doi.org/10.3390/sym9120297 - 05 Dec 2017

Viewed by 2390

Abstract

In this paper, first we show that under the assumption of the center of

h

being zero, diagonal non-abelian extensions of a regular Hom-Lie algebra

g

by a regular Hom-Lie algebra

h

are in one-to-one correspondence with Hom-Lie algebra morphisms from

g

to [...] Read more.

In this paper, first we show that under the assumption of the center of

h

being zero, diagonal non-abelian extensions of a regular Hom-Lie algebra

g

by a regular Hom-Lie algebra

h

are in one-to-one correspondence with Hom-Lie algebra morphisms from

g

to

Out (h)

. Then for a general Hom-Lie algebra morphism from

g

to

Out (h)

, we construct a cohomology class as the obstruction of existence of a non-abelian extension that induces the given Hom-Lie algebra morphism. Full article

7383 KiB

Open AccessArticle

Virtualized Network Function Orchestration System and Experimental Network Based QR Recognition for a 5G Mobile Access Network

by Misun Ahn, SeungGwan Lee and Sungwon Lee

Symmetry 2017, 9(12), 300; https://doi.org/10.3390/sym9120300 - 03 Dec 2017

Cited by 1 | Viewed by 5378

Abstract

This paper proposes a virtualized network function orchestration system based on Network Function Virtualization (NFV), one of the main technologies in 5G mobile networks. This system should provide connectivity between network devices and be able to create flexible network function and distribution. This [...] Read more.

This paper proposes a virtualized network function orchestration system based on Network Function Virtualization (NFV), one of the main technologies in 5G mobile networks. This system should provide connectivity between network devices and be able to create flexible network function and distribution. This system focuses more on access networks. By experimenting with various scenarios of user service established and activated in a network, we examine whether rapid adoption of new service is possible and whether network resources can be managed efficiently. The proposed method is based on Bluetooth transfer technology and mesh networking to provide automatic connections between network machines and on a Docker flat form, which is a container virtualization technology for setting and managing key functions. Additionally, the system includes a clustering and recovery measure regarding network function based on the Docker platform. We will briefly introduce the QR code perceived service as a user service to examine the proposal and based on this given service, we evaluate the function of the proposal and present analysis. Through the proposed approach, container relocation has been implemented according to a network device’s CPU usage and we confirm successful service through function evaluation on a real test bed. We estimate QR code recognition speed as the amount of network equipment is gradually increased, improving user service and confirm that the speed of recognition is increased as the assigned number of network devices is increased by the user service. Full article

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Open AccessArticle

Continuity of Fuzzified Functions Using the Generalized Extension Principle

by Hsien-Chung Wu

Symmetry 2017, 9(12), 299; https://doi.org/10.3390/sym9120299 - 01 Dec 2017

Cited by 4 | Viewed by 2476

Abstract

To fuzzify the crisp functions, the extension principle has been widely used for performing this fuzzification. The purpose of this paper is to investigate the continuity of fuzzified function using the more generalized extension principle. The Hausdorff metric will be invoked to study [...] Read more.

To fuzzify the crisp functions, the extension principle has been widely used for performing this fuzzification. The purpose of this paper is to investigate the continuity of fuzzified function using the more generalized extension principle. The Hausdorff metric will be invoked to study the continuity of fuzzified function. We also apply the principle of continuity of fuzzified function to the fuzzy topological vector space. Full article

(This article belongs to the Special Issue Fuzzy Sets Theory and Its Applications)

3627 KiB

Open AccessFeature PaperArticle

A Model for Shovel Capital Cost Estimation, Using a Hybrid Model of Multivariate Regression and Neural Networks

by Abdolreza Yazdani-Chamzini, Edmundas Kazimieras Zavadskas, Jurgita Antucheviciene and Romualdas Bausys

Symmetry 2017, 9(12), 298; https://doi.org/10.3390/sym9120298 - 01 Dec 2017

Cited by 18 | Viewed by 4837

Abstract

Cost estimation is an essential issue in feasibility studies in civil engineering. Many different methods can be applied to modelling costs. These methods can be divided into several main groups: (1) artificial intelligence, (2) statistical methods, and (3) analytical methods. In this paper, [...] Read more.

Cost estimation is an essential issue in feasibility studies in civil engineering. Many different methods can be applied to modelling costs. These methods can be divided into several main groups: (1) artificial intelligence, (2) statistical methods, and (3) analytical methods. In this paper, the multivariate regression (MVR) method, which is one of the most popular linear models, and the artificial neural network (ANN) method, which is widely applied to solving different prediction problems with a high degree of accuracy, have been combined to provide a cost estimate model for a shovel machine. This hybrid methodology is proposed, taking the advantages of MVR and ANN models in linear and nonlinear modelling, respectively. In the proposed model, the unique advantages of the MVR model in linear modelling are used first to recognize the existing linear structure in data, and, then, the ANN for determining nonlinear patterns in preprocessed data is applied. The results with three indices indicate that the proposed model is efficient and capable of increasing the prediction accuracy. Full article

(This article belongs to the Special Issue Civil Engineering and Symmetry)

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3205 KiB

Open AccessArticle

Tool-Wear Analysis Using Image Processing of the Tool Flank

by Ovidiu Gheorghe Moldovan, Simona Dzitac, Ioan Moga, Tiberiu Vesselenyi and Ioan Dzitac

Symmetry 2017, 9(12), 296; https://doi.org/10.3390/sym9120296 - 30 Nov 2017

Cited by 29 | Viewed by 5478

Abstract

Flexibility of manufacturing systems is an essential factor in maintaining the competitiveness of industrial production. Flexibility can be defined in several ways and according to several factors, but in order to obtain adequate results in implementing a flexible manufacturing system able to compete [...] Read more.

Flexibility of manufacturing systems is an essential factor in maintaining the competitiveness of industrial production. Flexibility can be defined in several ways and according to several factors, but in order to obtain adequate results in implementing a flexible manufacturing system able to compete on the market, a high level of autonomy (free of human intervention) of the manufacturing system must be achieved. There are many factors that can disturb the production process and reduce the autonomy of the system, because of the need of human intervention to overcome these disturbances. One of these factors is tool wear. The aim of this paper is to present an experimental study on the possibility to determine the state of tool wear in a flexible manufacturing cell environment, using image acquisition and processing methods. Full article

(This article belongs to the Special Issue Civil Engineering and Symmetry)

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1164 KiB

Open AccessReview

Green Cloud Computing: A Literature Survey

by Laura-Diana Radu

Symmetry 2017, 9(12), 295; https://doi.org/10.3390/sym9120295 - 30 Nov 2017

Cited by 70 | Viewed by 23570

Abstract

Cloud computing is a dynamic field of information and communication technologies (ICTs), introducing new challenges for environmental protection. Cloud computing technologies have a variety of application domains, since they offer scalability, are reliable and trustworthy, and offer high performance at relatively low cost. [...] Read more.

Cloud computing is a dynamic field of information and communication technologies (ICTs), introducing new challenges for environmental protection. Cloud computing technologies have a variety of application domains, since they offer scalability, are reliable and trustworthy, and offer high performance at relatively low cost. The cloud computing revolution is redesigning modern networking, and offering promising environmental protection prospects as well as economic and technological advantages. These technologies have the potential to improve energy efficiency and to reduce carbon footprints and (e-)waste. These features can transform cloud computing into green cloud computing. In this survey, we review the main achievements of green cloud computing. First, an overview of cloud computing is given. Then, recent studies and developments are summarized, and environmental issues are specifically addressed. Finally, future research directions and open problems regarding green cloud computing are presented. This survey is intended to serve as up-to-date guidance for research with respect to green cloud computing. Full article

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Symmetry, Volume 9, Issue 12 (December 2017) – 36 articles

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