Next Issue
Previous Issue

Table of Contents

Symmetry, Volume 9, Issue 10 (October 2017)

  • Issues are regarded as officially published after their release is announced to the table of contents alert mailing list.
  • You may sign up for e-mail alerts to receive table of contents of newly released issues.
  • PDF is the official format for papers published in both, html and pdf forms. To view the papers in pdf format, click on the "PDF Full-text" link, and use the free Adobe Readerexternal link to open them.
Cover Story (view full-size image) Lorentz symmetry asserts that the vacuum has no special directions, and therefore clocks tick at [...] Read more.
View options order results:
result details:
Displaying articles 1-49
Export citation of selected articles as:
Open AccessArticle A Method for Fuzzy Soft Sets in Decision-Making Based on an Ideal Solution
Symmetry 2017, 9(10), 246; https://doi.org/10.3390/sym9100246
Received: 25 September 2017 / Revised: 17 October 2017 / Accepted: 18 October 2017 / Published: 23 October 2017
Cited by 7 | PDF Full-text (398 KB) | HTML Full-text | XML Full-text
Abstract
In this paper, a decision model based on a fuzzy soft set and ideal solution approaches is proposed. This new decision-making method uses the divide-and-conquer algorithm, and it is different from the existing algorithm (the choice value based approach and the comparison score
[...] Read more.
In this paper, a decision model based on a fuzzy soft set and ideal solution approaches is proposed. This new decision-making method uses the divide-and-conquer algorithm, and it is different from the existing algorithm (the choice value based approach and the comparison score based approach). The ideal solution is generated according to each attribute (pros or cons of the attributes, with or without constraints) of the fuzzy soft sets. Finally, the weighted Hamming distance is used to compute all possible alternatives and get the final result. The core of the decision process is the design phase, the existing decision models based on soft sets mostly neglect the analysis of attributes and decision objectives. This algorithm emphasizes the correct expression of the purpose of the decision maker and the analysis of attributes, as well as the explicit decision function. Additionally, this paper shows the fact that the rank reversal phenomenon occurs in the comparison score algorithm, and an example is provided to illustrate the rank reversal phenomenon. Experiments indicate that the decision model proposed in this paper is efficient and will be useful for practical problems. In addition, as a general model, it can be extended to a wider range of fields, such as classifications, optimization problems, etc. Full article
(This article belongs to the Special Issue Fuzzy Techniques for Decision Making) Printed Edition available
Figures

Figure 1

Open AccessFeature PaperArticle Using Comparisons of Clock Frequencies and Sidereal Variation to Probe Lorentz Violation
Symmetry 2017, 9(10), 245; https://doi.org/10.3390/sym9100245
Received: 1 October 2017 / Revised: 17 October 2017 / Accepted: 18 October 2017 / Published: 23 October 2017
Cited by 1 | PDF Full-text (3600 KB) | HTML Full-text | XML Full-text
Abstract
This paper discusses clock-comparison experiments, which may be used to test Lorentz symmetry to an extremely high level of precision. We include a brief overview of theoretical predictions for signals of Lorentz violation in clock-comparison experiments and summarize results of experiments that have
[...] Read more.
This paper discusses clock-comparison experiments, which may be used to test Lorentz symmetry to an extremely high level of precision. We include a brief overview of theoretical predictions for signals of Lorentz violation in clock-comparison experiments and summarize results of experiments that have been performed to date. Full article
(This article belongs to the Special Issue Violation of Lorentz Symmetry)
Figures

Figure 1

Open AccessArticle Self-Adaptive Pre-Processing Methodology for Big Data Stream Mining in Internet of Things Environmental Sensor Monitoring
Symmetry 2017, 9(10), 244; https://doi.org/10.3390/sym9100244
Received: 30 September 2017 / Revised: 11 October 2017 / Accepted: 15 October 2017 / Published: 21 October 2017
Cited by 3 | PDF Full-text (3246 KB) | HTML Full-text | XML Full-text
Abstract
Over the years, advanced IT technologies have facilitated the emergence of new ways of generating and gathering data rapidly, continuously, and largely and are associated with a new research and application branch, namely, data stream mining (DSM). Among those multiple scenarios of DSM,
[...] Read more.
Over the years, advanced IT technologies have facilitated the emergence of new ways of generating and gathering data rapidly, continuously, and largely and are associated with a new research and application branch, namely, data stream mining (DSM). Among those multiple scenarios of DSM, the Internet of Things (IoT) plays a significant role, with a typical meaning of a tough and challenging computational case of big data. In this paper, we describe a self-adaptive approach to the pre-processing step of data stream classification. The proposed algorithm allows different divisions with both variable numbers and lengths of sub-windows under a whole sliding window on an input stream, and clustering-based particle swarm optimization (CPSO) is adopted as the main metaheuristic search method to guarantee that its stream segmentations are effective and adaptive to itself. In order to create a more abundant search space, statistical feature extraction (SFX) is applied after variable partitions of the entire sliding window. We validate and test the effort of our algorithm with other temporal methods according to several IoT environmental sensor monitoring datasets. The experiments yield encouraging outcomes, supporting the reality that picking significant appropriate variant sub-window segmentations heuristically with an incorporated clustering technique merit would allow these to perform better than others. Full article
(This article belongs to the Special Issue Emerging Approaches and Advances in Big Data)
Figures

Figure 1

Open AccessArticle Factors Affecting the Perception of 3D Facial Symmetry from 2D Projections
Symmetry 2017, 9(10), 243; https://doi.org/10.3390/sym9100243
Received: 28 September 2017 / Revised: 18 October 2017 / Accepted: 19 October 2017 / Published: 21 October 2017
PDF Full-text (1308 KB) | HTML Full-text | XML Full-text
Abstract
Facial symmetry is believed to have an evolutionary significance and so its detection should be robust in natural settings. Previous studies of facial symmetry detection have used front views of faces where the decision could be made on 2D image properties rather than
[...] Read more.
Facial symmetry is believed to have an evolutionary significance and so its detection should be robust in natural settings. Previous studies of facial symmetry detection have used front views of faces where the decision could be made on 2D image properties rather than 3D facial properties. These studies also employed comparative judgements, which could be influenced by attractiveness rather than symmetry. Two experiments explored the ability to detect typical levels of 3D facial asymmetry (contrasted with wholly symmetrical faces) from 2D projections of faces. Experiment 1 showed that asymmetry detection was impaired by inversion but even more impaired by 90 degrees rotation demonstrating the importance of the vertical reflection. Asymmetry detection was also reduced by yaw rotation of the head but still above-chance at 30 degrees rotation. Experiment 2 explored the effect of asymmetrical lighting and yaw rotation up to 45 degrees. Detection of asymmetry was affected by asymmetrical lighting and yaw rotation in a non-additive manner. The results are discussed in terms of the special role that faces and vertical symmetry play in visual perception. Full article
Figures

Figure 1

Open AccessArticle Lattice-Based Revocable Certificateless Signature
Symmetry 2017, 9(10), 242; https://doi.org/10.3390/sym9100242
Received: 27 September 2017 / Revised: 16 October 2017 / Accepted: 18 October 2017 / Published: 20 October 2017
PDF Full-text (302 KB) | HTML Full-text | XML Full-text
Abstract
Certificateless signatures (CLS) are noticeable because they may resolve the key escrow problem in ID-based signatures and break away the management problem regarding certificate in conventional signatures. However, the security of the mostly previous CLS schemes relies on the difficulty of solving discrete
[...] Read more.
Certificateless signatures (CLS) are noticeable because they may resolve the key escrow problem in ID-based signatures and break away the management problem regarding certificate in conventional signatures. However, the security of the mostly previous CLS schemes relies on the difficulty of solving discrete logarithm or large integer factorization problems. These two problems would be solved by quantum computers in the future so that the signature schemes based on them will also become insecure. For post-quantum cryptography, lattice-based cryptography is significant due to its efficiency and security. However, no study on addressing the revocation problem in the existing lattice-based CLS schemes is presented. In this paper, we focus on the revocation issue and present the first revocable CLS (RCLS) scheme over lattices. Based on the short integer solution (SIS) assumption over lattices, the proposed lattice-based RCLS scheme is shown to be existential unforgeability against adaptive chosen message attacks. By performance analysis and comparisons, the proposed lattice-based RCLS scheme is better than the previously proposed lattice-based CLS scheme, in terms of private key size, signature length and the revocation mechanism. Full article
Open AccessArticle Multi-Objective Optimization Algorithm Based on Sperm Fertilization Procedure (MOSFP)
Symmetry 2017, 9(10), 241; https://doi.org/10.3390/sym9100241
Received: 7 September 2017 / Revised: 11 October 2017 / Accepted: 12 October 2017 / Published: 20 October 2017
Cited by 1 | PDF Full-text (3479 KB) | HTML Full-text | XML Full-text
Abstract
In this paper, we propose an extended multi-objective version of single objective optimization algorithm called sperm swarm optimization algorithm. The proposed multi-objective optimization algorithm based on sperm fertilization procedure (MOSFP) operates based on Pareto dominance and a crowding factor, that crowd and filter
[...] Read more.
In this paper, we propose an extended multi-objective version of single objective optimization algorithm called sperm swarm optimization algorithm. The proposed multi-objective optimization algorithm based on sperm fertilization procedure (MOSFP) operates based on Pareto dominance and a crowding factor, that crowd and filter out the list of the best sperms (global best values). We divide the sperm swarm into three equal parts, after that, different types of turbulence (mutation) operators are applied on these parts, such as uniform mutation, non-uniform mutation, and without any mutation. Our algorithm is compared against three well-known algorithms in the field of optimization. These algorithms are NSGA-II, SPEA2, and OMOPSO. These algorithms are compared using a very popular benchmark function suites called Zitzler-Deb-Thiele (ZDT) and Walking-Fish-Group (WFG). We also adopt three quality metrics to compare the convergence, accuracy, and diversity of these algorithms, including, inverted generational distance (IGD), spread (SP), and epsilon (∈). The experimental results show that the performance of the proposed MOSFP is highly competitive, which outperformed OMOPSO in solving problems such as ZDT3, WFG5, and WFG8. In addition, the proposed MOSFP outperformed both of NSGA-II or SPEA2 algorithms in solving all the problems. Full article
Figures

Figure 1

Open AccessArticle On Elastic Symmetry Identification for Polycrystalline Materials
Symmetry 2017, 9(10), 240; https://doi.org/10.3390/sym9100240
Received: 17 September 2017 / Revised: 14 October 2017 / Accepted: 15 October 2017 / Published: 20 October 2017
PDF Full-text (14832 KB) | HTML Full-text | XML Full-text
Abstract
The products made by the forming of polycrystalline metals and alloys, which are in high demand in modern industries, have pronounced inhomogeneous distribution of grain orientations. The presence of specific orientation modes in such materials, i.e., crystallographic texture, is responsible for anisotropy of
[...] Read more.
The products made by the forming of polycrystalline metals and alloys, which are in high demand in modern industries, have pronounced inhomogeneous distribution of grain orientations. The presence of specific orientation modes in such materials, i.e., crystallographic texture, is responsible for anisotropy of their physical and mechanical properties, e.g., elasticity. A type of anisotropy is usually unknown a priori, and possible ways of its determination is of considerable interest both from theoretical and practical viewpoints. In this work, emphasis is placed on the identification of elasticity classes of polycrystalline materials. By the newly introduced concept of “elasticity class” the union of congruent tensor subspaces of a special form is understood. In particular, it makes it possible to consider the so-called symmetry classification, which is widely spread in solid mechanics. The problem of identification of linear elasticity class for anisotropic material with elastic moduli given in an arbitrary orthonormal basis is formulated. To solve this problem, a general procedure based on constructing the hierarchy of approximations of elasticity tensor in different classes is formulated. This approach is then applied to analyze changes in the elastic symmetry of a representative volume element of polycrystalline copper during numerical experiments on severe plastic deformation. The microstructure evolution is described using a two-level crystal elasto-visco-plasticity model. The well-defined structures, which are indicative of the existence of essentially inhomogeneous distribution of crystallite orientations, were obtained in each experiment. However, the texture obtained in the quasi-axial upsetting experiment demonstrates the absence of significant macroscopic elastic anisotropy. Using the identification framework, it has been shown that the elasticity tensor corresponding to the resultant microstructure proves to be almost isotropic. Full article
Figures

Figure 1

Open AccessArticle Fuzzy Logic-Based Model That Incorporates Personality Traits for Heterogeneous Pedestrians
Symmetry 2017, 9(10), 239; https://doi.org/10.3390/sym9100239
Received: 15 September 2017 / Revised: 7 October 2017 / Accepted: 13 October 2017 / Published: 20 October 2017
Cited by 1 | PDF Full-text (7017 KB) | HTML Full-text | XML Full-text
Abstract
Most models designed to simulate pedestrian dynamical behavior are based on the assumption that human decision-making can be described using precise values. This study proposes a new pedestrian model that incorporates fuzzy logic theory into a multi-agent system to address cognitive behavior that
[...] Read more.
Most models designed to simulate pedestrian dynamical behavior are based on the assumption that human decision-making can be described using precise values. This study proposes a new pedestrian model that incorporates fuzzy logic theory into a multi-agent system to address cognitive behavior that introduces uncertainty and imprecision during decision-making. We present a concept of decision preferences to represent the intrinsic control factors of decision-making. To realize the different decision preferences of heterogeneous pedestrians, the Five-Factor (OCEAN) personality model is introduced to model the psychological characteristics of individuals. Then, a fuzzy logic-based approach is adopted for mapping the relationships between the personality traits and the decision preferences. Finally, we have developed an application using our model to simulate pedestrian dynamical behavior in several normal or non-panic scenarios, including a single-exit room, a hallway with obstacles, and a narrowing passage. The effectiveness of the proposed model is validated with a user study. The results show that the proposed model can generate more reasonable and heterogeneous behavior in the simulation and indicate that individual personality has a noticeable effect on pedestrian dynamical behavior. Full article
(This article belongs to the Special Issue Fuzzy Techniques for Decision Making) Printed Edition available
Figures

Figure 1

Open AccessArticle The Interval Cognitive Network Process for Multi-Attribute Decision-Making
Symmetry 2017, 9(10), 238; https://doi.org/10.3390/sym9100238
Received: 5 October 2017 / Revised: 14 October 2017 / Accepted: 16 October 2017 / Published: 19 October 2017
PDF Full-text (314 KB) | HTML Full-text | XML Full-text
Abstract
Aiming at combining the good characteristics of a differential scale in representing human cognition and the favorable properties of interval judgments in expressing decision-makers’ uncertainty, this paper proposes the interval cognitive network process (I-CNP) to extend the primitive cognition network process (P-CNP) to
[...] Read more.
Aiming at combining the good characteristics of a differential scale in representing human cognition and the favorable properties of interval judgments in expressing decision-makers’ uncertainty, this paper proposes the interval cognitive network process (I-CNP) to extend the primitive cognition network process (P-CNP) to handle interval judgments. The key points of I-CNP include a consistency definition for an interval pairwise opposite matrix (IPOM) and a method to derive interval utilities from an IPOM. This paper defines a feasible region-based consistency definition and a transitivity based consistency definition for an IPOM. Both of the two definitions are equivalent to the consistency definition for a crisp pairwise opposite matrix (POM) when an IPOM is reduced to a POM. Two methods that are able to derive interval utilities from both consistent and inconsistent IPOMs are developed based on the two definitions. Four numerical examples are used to illustrate the proposed methods and to compare I-CNP to interval analytic hierarchy process (IAHP). The results show that I-CNP reflects the decision-makers’ cognition better, and that the suggestions provided by I-CNP are more convincing. I-CNP provides new useful alternative tools for multi-attribute decision-making problems. Full article
Open AccessArticle Internet of THings Area Coverage Analyzer (ITHACA) for Complex Topographical Scenarios
Symmetry 2017, 9(10), 237; https://doi.org/10.3390/sym9100237
Received: 31 August 2017 / Revised: 22 September 2017 / Accepted: 9 October 2017 / Published: 19 October 2017
Cited by 3 | PDF Full-text (5439 KB) | HTML Full-text | XML Full-text
Abstract
The number of connected devices is increasing worldwide. Not only in contexts like the Smart City, but also in rural areas, to provide advanced features like smart farming or smart logistics. Thus, wireless network technologies to efficiently allocate Internet of Things (IoT) and
[...] Read more.
The number of connected devices is increasing worldwide. Not only in contexts like the Smart City, but also in rural areas, to provide advanced features like smart farming or smart logistics. Thus, wireless network technologies to efficiently allocate Internet of Things (IoT) and Machine to Machine (M2M) communications are necessary. Traditional cellular networks like Global System for Mobile communications (GSM) are widely used worldwide for IoT environments. Nevertheless, Low Power Wide Area Networks (LP-WAN) are becoming widespread as infrastructure for present and future IoT and M2M applications. Based also on a subscription service, the LP-WAN technology SIGFOXTM may compete with cellular networks in the M2M and IoT communications market, for instance in those projects where deploying the whole communications infrastructure is too complex or expensive. For decision makers to decide the most suitable technology for each specific application, signal coverage is within the key features. Unfortunately, besides simulated coverage maps, decision-makers do not have real coverage maps for SIGFOXTM, as they can be found for cellular networks. Thereby, we propose Internet of THings Area Coverage Analyzer (ITHACA), a signal analyzer prototype to provide automated signal coverage maps and analytics for LP-WAN. Experiments performed in the Gran Canaria Island, Spain (with both urban and complex topographic rural environments), returned a real SIGFOXTM service availability above 97% and above 11% more coverage with respect to the company-provided simulated maps. We expect that ITHACA may help decision makers to deploy the most suitable technologies for future IoT and M2M projects. Full article
(This article belongs to the Special Issue Applications of Internet of Things)
Figures

Figure 1

Open AccessArticle SINR-Based MCS Level Adaptation in CSMA/CA Wireless Networks to Embrace IoT Devices
Symmetry 2017, 9(10), 236; https://doi.org/10.3390/sym9100236
Received: 20 September 2017 / Revised: 13 October 2017 / Accepted: 16 October 2017 / Published: 19 October 2017
PDF Full-text (3297 KB) | HTML Full-text | XML Full-text
Abstract
This paper presents an automatic modulation and coding scheme (MCS) level adaptation algorithm to embrace Internet of Things (IoT) devices by improving the area spectral efficiency of carrier-sense multiple access with collision avoidance (CSMA/CA) wireless networks. In the proposed algorithm, senders of CSMA/CA
[...] Read more.
This paper presents an automatic modulation and coding scheme (MCS) level adaptation algorithm to embrace Internet of Things (IoT) devices by improving the area spectral efficiency of carrier-sense multiple access with collision avoidance (CSMA/CA) wireless networks. In the proposed algorithm, senders of CSMA/CA wireless networks use the signal to interference plus noise ratio of acknowledgment frames from their receivers to estimate channel statuses between the senders and the receivers. Using the estimated channel status of each receiver, senders control sending rates of traffic by adjusting MCS levels of packets destined for each receiver. We use Poisson point processes (PPPs) to model the locations of participating nodes (i.e., access points and wireless devices) in a given area. We evaluate the effectiveness of the proposed algorithm using an event-driven ns-2 simulator for various PPP densities of access points and wireless devices. Full article
(This article belongs to the Special Issue Advances in Future Internet and Industrial Internet of Things)
Figures

Figure 1

Open AccessFeature PaperArticle A Retinal Vessel Detection Approach Based on Shearlet Transform and Indeterminacy Filtering on Fundus Images
Symmetry 2017, 9(10), 235; https://doi.org/10.3390/sym9100235
Received: 21 September 2017 / Revised: 9 October 2017 / Accepted: 16 October 2017 / Published: 19 October 2017
Cited by 3 | PDF Full-text (2360 KB) | HTML Full-text | XML Full-text
Abstract
A fundus image is an effective tool for ophthalmologists studying eye diseases. Retinal vessel detection is a significant task in the identification of retinal disease regions. This study presents a retinal vessel detection approach using shearlet transform and indeterminacy filtering. The fundus image’s
[...] Read more.
A fundus image is an effective tool for ophthalmologists studying eye diseases. Retinal vessel detection is a significant task in the identification of retinal disease regions. This study presents a retinal vessel detection approach using shearlet transform and indeterminacy filtering. The fundus image’s green channel is mapped in the neutrosophic domain via shearlet transform. The neutrosophic domain images are then filtered with an indeterminacy filter to reduce the indeterminacy information. A neural network classifier is employed to identify the pixels whose inputs are the features in neutrosophic images. The proposed approach is tested on two datasets, and a receiver operating characteristic curve and the area under the curve are employed to evaluate experimental results quantitatively. The area under the curve values are 0.9476 and 0.9469 for each dataset respectively, and 0.9439 for both datasets. The comparison with the other algorithms also illustrates that the proposed method yields the highest evaluation measurement value and demonstrates the efficiency and accuracy of the proposed method. Full article
(This article belongs to the Special Issue Neutrosophic Theories Applied in Engineering)
Figures

Figure 1

Open AccessFeature PaperArticle Managing Non-Homogeneous Information and Experts’ Psychological Behavior in Group Emergency Decision Making
Symmetry 2017, 9(10), 234; https://doi.org/10.3390/sym9100234
Received: 25 September 2017 / Revised: 11 October 2017 / Accepted: 13 October 2017 / Published: 18 October 2017
Cited by 5 | PDF Full-text (2976 KB) | HTML Full-text | XML Full-text
Abstract
After an emergency event (EE) happens, emergency decision making (EDM) is a common and effective way to deal with the emergency situation, which plays an important role in mitigating its level of harm. In the real world, it is a big challenge for
[...] Read more.
After an emergency event (EE) happens, emergency decision making (EDM) is a common and effective way to deal with the emergency situation, which plays an important role in mitigating its level of harm. In the real world, it is a big challenge for an individual emergency manager (EM) to make a proper and comprehensive decision for coping with an EE. Consequently, many practical EDM problems drive group emergency decision making (GEDM) problems whose main limitations are related to the lack of flexibility in knowledge elicitation, disagreements in the group and the consideration of experts’ psychological behavior in the decision process. Hence, this paper proposes a novel GEDM approach that allows more flexibility for preference elicitation under uncertainty, provides a consensus process to avoid disagreements and considers experts’ psychological behavior by using the fuzzy TODIM method based on prospect theory. Eventually, a group decision support system (GDSS) is developed to support the whole GEDM process defined in the proposed method demonstrating its novelty, validity and feasibility. Full article
(This article belongs to the Special Issue Fuzzy Techniques for Decision Making) Printed Edition available
Figures

Figure 1

Open AccessArticle How to Obtain Common Criteria Certification of Smart TV for Home IoT Security and Reliability
Symmetry 2017, 9(10), 233; https://doi.org/10.3390/sym9100233
Received: 31 July 2017 / Revised: 21 September 2017 / Accepted: 25 September 2017 / Published: 17 October 2017
PDF Full-text (724 KB) | HTML Full-text | XML Full-text
Abstract
In the new era of IoT (Internet of Things), numerous gadgets and services include innovative IoT technologies that provide customers with convenience and improve their quality of life. Smart TVs are typical IoT devices that offer broadcasting services. However, they are susceptible to
[...] Read more.
In the new era of IoT (Internet of Things), numerous gadgets and services include innovative IoT technologies that provide customers with convenience and improve their quality of life. Smart TVs are typical IoT devices that offer broadcasting services. However, they are susceptible to security intrusions via e-mail, media players, cameras, and internet connectivity. The frequency of hacking through malicious applications installed in Smart TV has rapidly increased. Therefore, appropriate countermeasures should be developed immediately. In April 2017, we (with LG electronics) received the ‘world-first’ Common Criteria EAL2 (Evaluation Assurance Level 2) certification for Smart TVs. As far as we know, no Smart TV has received a Common Criteria EAL2 security certification until now. This article describes our experience with the certification process and examines several security and reliability aspects of Smart TVs. Full article
(This article belongs to the Special Issue Advances in Future Internet and Industrial Internet of Things)
Figures

Figure 1

Open AccessArticle Open Gromov-Witten Invariants from the Augmentation Polynomial
Symmetry 2017, 9(10), 232; https://doi.org/10.3390/sym9100232
Received: 30 August 2017 / Revised: 6 October 2017 / Accepted: 10 October 2017 / Published: 17 October 2017
PDF Full-text (284 KB) | HTML Full-text | XML Full-text
Abstract
A conjecture of Aganagic and Vafa relates the open Gromov-Witten theory of X=OP1(1,1) to the augmentation polynomial of Legendrian contact homology. We describe how to use this conjecture to compute genus zero,
[...] Read more.
A conjecture of Aganagic and Vafa relates the open Gromov-Witten theory of X = O P 1 ( 1 , 1 ) to the augmentation polynomial of Legendrian contact homology. We describe how to use this conjecture to compute genus zero, one boundary component open Gromov-Witten invariants for Lagrangian submanifolds L K X obtained from the conormal bundles of knots K S 3 . This computation is then performed for two non-toric examples (the figure-eight and three-twist knots). For ( r , s ) torus knots, the open Gromov-Witten invariants can also be computed using Atiyah-Bott localization. Using this result for the unknot and the ( 3 , 2 ) torus knot, we show that the augmentation polynomial can be derived from these open Gromov-Witten invariants. Full article
(This article belongs to the Special Issue Knot Theory and Its Applications)
Figures

Figure 1

Open AccessArticle Multiple Signal Classification Algorithm Based Electric Dipole Source Localization Method in an Underwater Environment
Symmetry 2017, 9(10), 231; https://doi.org/10.3390/sym9100231
Received: 27 June 2017 / Revised: 9 August 2017 / Accepted: 13 October 2017 / Published: 17 October 2017
Cited by 1 | PDF Full-text (3665 KB) | HTML Full-text | XML Full-text
Abstract
A novel localization method based on multiple signal classification (MUSIC) algorithm is proposed for positioning an electric dipole source in a confined underwater environment by using electric dipole-receiving antenna array. In this method, the boundary element method (BEM) is introduced to analyze the
[...] Read more.
A novel localization method based on multiple signal classification (MUSIC) algorithm is proposed for positioning an electric dipole source in a confined underwater environment by using electric dipole-receiving antenna array. In this method, the boundary element method (BEM) is introduced to analyze the boundary of the confined region by use of a matrix equation. The voltage of each dipole pair is used as spatial-temporal localization data, and it does not need to obtain the field component in each direction compared with the conventional fields based localization method, which can be easily implemented in practical engineering applications. Then, a global-multiple region-conjugate gradient (CG) hybrid search method is used to reduce the computation burden and to improve the operation speed. Two localization simulation models and a physical experiment are conducted. Both the simulation results and physical experiment result provide accurate positioning performance, with the help to verify the effectiveness of the proposed localization method in underwater environments. Full article
Figures

Figure 1

Open AccessArticle Gravity Theories with Background Fields and Spacetime Symmetry Breaking
Symmetry 2017, 9(10), 230; https://doi.org/10.3390/sym9100230
Received: 25 September 2017 / Revised: 6 October 2017 / Accepted: 10 October 2017 / Published: 16 October 2017
Cited by 1 | PDF Full-text (225 KB) | HTML Full-text | XML Full-text
Abstract
An overview is given of effective gravitational field theories with fixed background fields that break spacetime symmetry. The behavior of the background fields and the types of excitations that can occur depend on whether the symmetry breaking is explicit or spontaneous. For example,
[...] Read more.
An overview is given of effective gravitational field theories with fixed background fields that break spacetime symmetry. The behavior of the background fields and the types of excitations that can occur depend on whether the symmetry breaking is explicit or spontaneous. For example, when the breaking is spontaneous, the background field is dynamical and massless Nambu–Goldstone and massive Higgs excitations can appear. However, if the breaking is explicit, the background is nondynamical, and in this case additional metric or vierbein excitations occur due to the loss of local symmetry, or these excitations can be replaced by dynamical scalar fields using a Stückelberg approach. The interpretation of Noether identities that must hold in each case differs, depending on the type of symmetry breaking, and this affects the nature of the consistency conditions that must hold. The Noether identities also shed light on why the Stückelberg approach works, and how it is able to restore the broken spacetime symmetry in a theory with explicit breaking. Full article
(This article belongs to the Special Issue Violation of Lorentz Symmetry)
Open AccessArticle A General Zero Attraction Proportionate Normalized Maximum Correntropy Criterion Algorithm for Sparse System Identification
Symmetry 2017, 9(10), 229; https://doi.org/10.3390/sym9100229
Received: 18 September 2017 / Revised: 1 October 2017 / Accepted: 6 October 2017 / Published: 15 October 2017
Cited by 1 | PDF Full-text (1951 KB) | HTML Full-text | XML Full-text
Abstract
A general zero attraction (GZA) proportionate normalized maximum correntropy criterion (GZA-PNMCC) algorithm is devised and presented on the basis of the proportionate-type adaptive filter techniques and zero attracting theory to highly improve the sparse system estimation behavior of the classical MCC algorithm within
[...] Read more.
A general zero attraction (GZA) proportionate normalized maximum correntropy criterion (GZA-PNMCC) algorithm is devised and presented on the basis of the proportionate-type adaptive filter techniques and zero attracting theory to highly improve the sparse system estimation behavior of the classical MCC algorithm within the framework of the sparse system identifications. The newly-developed GZA-PNMCC algorithm is carried out by introducing a parameter adjusting function into the cost function of the typical proportionate normalized maximum correntropy criterion (PNMCC) to create a zero attraction term. The developed optimization framework unifies the derivation of the zero attraction-based PNMCC algorithms. The developed GZA-PNMCC algorithm further exploits the impulsive response sparsity in comparison with the proportionate-type-based NMCC algorithm due to the GZA zero attraction. The superior performance of the GZA-PNMCC algorithm for estimating a sparse system in a non-Gaussian noise environment is proven by simulations. Full article
Figures

Figure 1

Open AccessArticle Decomposition and Intersection of Two Fuzzy Numbers for Fuzzy Preference Relations
Symmetry 2017, 9(10), 228; https://doi.org/10.3390/sym9100228
Received: 11 September 2017 / Revised: 7 October 2017 / Accepted: 9 October 2017 / Published: 14 October 2017
Cited by 2 | PDF Full-text (1588 KB) | HTML Full-text | XML Full-text
Abstract
In fuzzy decision problems, the ordering of fuzzy numbers is the basic problem. The fuzzy preference relation is the reasonable representation of preference relations by a fuzzy membership function. This paper studies Nakamura’s and Kołodziejczyk’s preference relations. Eight cases, each representing different levels
[...] Read more.
In fuzzy decision problems, the ordering of fuzzy numbers is the basic problem. The fuzzy preference relation is the reasonable representation of preference relations by a fuzzy membership function. This paper studies Nakamura’s and Kołodziejczyk’s preference relations. Eight cases, each representing different levels of overlap between two triangular fuzzy numbers are considered. We analyze the ranking behaviors of all possible combinations of the decomposition and intersection of two fuzzy numbers through eight extensive test cases. The results indicate that decomposition and intersection can affect the fuzzy preference relations, and thereby the final ranking of fuzzy numbers. Full article
(This article belongs to the Special Issue Fuzzy Techniques for Decision Making) Printed Edition available
Figures

Figure 1a

Open AccessArticle Bounded Solutions to Nonhomogeneous Linear Second-Order Difference Equations
Symmetry 2017, 9(10), 227; https://doi.org/10.3390/sym9100227
Received: 29 September 2017 / Revised: 8 October 2017 / Accepted: 8 October 2017 / Published: 14 October 2017
Cited by 2 | PDF Full-text (325 KB) | HTML Full-text | XML Full-text
Abstract
By using some solvability methods and the contraction mapping principle are investigated bounded, as well as periodic solutions to some classes of nonhomogeneous linear second-order difference equations on domains N0, ZN2 and Z. The case when the
[...] Read more.
By using some solvability methods and the contraction mapping principle are investigated bounded, as well as periodic solutions to some classes of nonhomogeneous linear second-order difference equations on domains N 0 , Z N 2 and Z . The case when the coefficients of the equation are constant and the zeros of the characteristic polynomial associated to the corresponding homogeneous equation do not belong to the unit circle is described in detail. Full article
Open AccessFeature PaperArticle Skein Invariants of Links and Their State Sum Models
Symmetry 2017, 9(10), 226; https://doi.org/10.3390/sym9100226
Received: 19 September 2017 / Revised: 2 October 2017 / Accepted: 9 October 2017 / Published: 13 October 2017
Cited by 2 | PDF Full-text (448 KB) | HTML Full-text | XML Full-text
Abstract
We present the new skein invariants of classical links, H[H], K[K] and D[D], based on the invariants of links, H, K and D, denoting the regular isotopy version of the
[...] Read more.
We present the new skein invariants of classical links, H [ H ] , K [ K ] and D [ D ] , based on the invariants of links, H, K and D, denoting the regular isotopy version of the Homflypt polynomial, the Kauffman polynomial and the Dubrovnik polynomial. The invariants are obtained by abstracting the skein relation of the corresponding invariant and making a new skein algorithm comprising two computational levels: first producing unlinked knotted components, then evaluating the resulting knots. The invariants in this paper, were revealed through the skein theoretic definition of the invariants Θ d related to the Yokonuma–Hecke algebras and their 3-variable generalization Θ , which generalizes the Homflypt polynomial. H [ H ] is the regular isotopy counterpart of Θ . The invariants K [ K ] and D [ D ] are new generalizations of the Kauffman and the Dubrovnik polynomials. We sketch skein theoretic proofs of the well-definedness and topological properties of these invariants. The invariants of this paper are reformulated into summations of the generating invariants (H, K, D) on sublinks of the given link L, obtained by partitioning L into collections of sublinks. The first such reformulation was achieved by W.B.R. Lickorish for the invariant Θ and we generalize it to the Kauffman and Dubrovnik polynomial cases. State sum models are formulated for all the invariants. These state summation models are based on our skein template algorithm which formalizes the skein theoretic process as an analogue of a statistical mechanics partition function. Relationships with statistical mechanics models are articulated. Finally, we discuss physical situations where a multi-leveled course of action is taken naturally. Full article
(This article belongs to the Special Issue Knot Theory and Its Applications)
Figures

Figure 1

Open AccessArticle Magnetic Transport in Spin Antiferromagnets for Spintronics Applications
Symmetry 2017, 9(10), 225; https://doi.org/10.3390/sym9100225
Received: 29 July 2017 / Revised: 12 September 2017 / Accepted: 6 October 2017 / Published: 13 October 2017
PDF Full-text (241 KB) | HTML Full-text | XML Full-text
Abstract
Had magnetic monopoles been ubiquitous as electrons are, we would probably have had a different form of matter, and power plants based on currents of these magnetic charges would have been a familiar scene of modern technology. Magnetic dipoles do exist, however, and
[...] Read more.
Had magnetic monopoles been ubiquitous as electrons are, we would probably have had a different form of matter, and power plants based on currents of these magnetic charges would have been a familiar scene of modern technology. Magnetic dipoles do exist, however, and in principle one could wonder if we can use them to generate magnetic currents. In the present work, we address the issue of generating magnetic currents and magnetic thermal currents in electrically-insulating low-dimensional Heisenberg antiferromagnets by invoking the (broken) electricity-magnetism duality symmetry. The ground state of these materials is a spin-liquid state that can be described well via the Jordan–Wigner fermions, which permit an easy definition of the magnetic particle and thermal currents. The magnetic and magnetic thermal conductivities are calculated in the present work using the bond–mean field theory. The spin-liquid states in these antiferromagnets are either gapless or gapped liquids of spinless fermions whose flow defines a current just as the one defined for electrons in a Fermi liquid. The driving force for the magnetic current is a magnetic field with a gradient along the magnetic conductor. We predict the generation of a magneto-motive force and realization of magnetic circuits using low-dimensional Heisenberg antiferromagnets. The present work is also about claiming that what the experiments in spintronics attempt to do is trying to treat the magnetic degrees of freedoms on the same footing as the electronic ones. Full article
(This article belongs to the Special Issue Symmetry and Symmetry Breaking in Quantum Mechanics)
Open AccessArticle Asymmetric Equivalences in Fuzzy Logic
Symmetry 2017, 9(10), 224; https://doi.org/10.3390/sym9100224
Received: 25 September 2017 / Revised: 8 October 2017 / Accepted: 9 October 2017 / Published: 13 October 2017
PDF Full-text (281 KB) | HTML Full-text | XML Full-text
Abstract
We introduce a new class of operations called asymmetric equivalences. Several properties of asymmetric equivalence operations have been investigated. Based on the asymmetric equivalence, quasi-metric spaces are constructed on [0, 1]. Finally, we discuss symmetrization of asymmetric equivalences. Full article
(This article belongs to the Special Issue Symmetry in Fuzzy Sets and Systems)
Figures

Figure 1

Open AccessArticle Reversible Dual-Image-Based Hiding Scheme Using Block Folding Technique
Symmetry 2017, 9(10), 223; https://doi.org/10.3390/sym9100223
Received: 19 September 2017 / Revised: 6 October 2017 / Accepted: 9 October 2017 / Published: 12 October 2017
Cited by 1 | PDF Full-text (14363 KB) | HTML Full-text | XML Full-text
Abstract
The concept of a dual-image based scheme in information sharing consists of concealing secret messages in two cover images; only someone who has both stego-images can extract the secret messages. In 2015, Lu et al. proposed a center-folding strategy where each secret symbol
[...] Read more.
The concept of a dual-image based scheme in information sharing consists of concealing secret messages in two cover images; only someone who has both stego-images can extract the secret messages. In 2015, Lu et al. proposed a center-folding strategy where each secret symbol is folded into the reduced digit to reduce the distortion of the stego-image. Then, in 2016, Lu et al. used a frequency-based encoding strategy to reduce the distortion of the frequency of occurrence of the maximum absolute value. Because the folding strategy can obviously reduce the value, the proposed scheme includes the folding operation twice to further decrease the reduced digit. We use a frequency-based encoding strategy to encode a secret message and then use the block folding technique by performing the center-folding operation twice to embed secret messages. An indicator is needed to identify the sequence number of the folding operation. The proposed scheme collects several indicators to produce a combined code and hides the code in a pixel to reduce the size of the indicators. The experimental results show that the proposed method can achieve higher image quality under the same embedding rate or higher payload, which is better than other methods. Full article
(This article belongs to the Special Issue Information Technology and Its Applications)
Figures

Figure 1

Open AccessArticle Evaluation of Airplane Boarding/Deboarding Strategies: A Surrogate Experimental Test
Symmetry 2017, 9(10), 222; https://doi.org/10.3390/sym9100222
Received: 15 September 2017 / Revised: 1 October 2017 / Accepted: 9 October 2017 / Published: 11 October 2017
Cited by 2 | PDF Full-text (4526 KB) | HTML Full-text | XML Full-text
Abstract
Optimally organizing passengers boarding/deboarding an airplane offers a potential way to reduce the airplane turn time. The main contribution of our work is that we evaluate seven boarding strategies and two structured deboarding strategies by using a surrogate experimental test. Instead of boarding
[...] Read more.
Optimally organizing passengers boarding/deboarding an airplane offers a potential way to reduce the airplane turn time. The main contribution of our work is that we evaluate seven boarding strategies and two structured deboarding strategies by using a surrogate experimental test. Instead of boarding a real or mocked airplane, we carried out the experiment by organizing 40 participants to board a school bus with ten rows of four seats, symmetrically distributed on a single, central aisle. Experimental results confirm that the optimized strategies, i.e., Steffen and Steffen-lug, are superior to the traditional ones, i.e., Back-to-front, Window-to-aisle, and Random in time-saving and stability. However, the two structured deboarding strategies failed to reduce the deboarding time, and this result strongly suggests the prerequisites of applying such strategies only when, on average, passengers have a large amount of luggage. Besides, we further carried out a questionnaire survey of participants’ preferences on seat layout and discussed how those preferences influence the boarding time. Full article
(This article belongs to the Special Issue Civil Engineering and Symmetry)
Figures

Figure 1

Open AccessArticle Intelligent Aggregation Based on Content Routing Scheme for Cloud Computing
Symmetry 2017, 9(10), 221; https://doi.org/10.3390/sym9100221
Received: 8 September 2017 / Revised: 28 September 2017 / Accepted: 6 October 2017 / Published: 11 October 2017
Cited by 10 | PDF Full-text (13885 KB) | HTML Full-text | XML Full-text
Abstract
Cloud computing has emerged as today’s most exciting computing paradigm for providing services using a shared framework, which opens a new door for solving the problems of the explosive growth of digital resource demands and their corresponding convenience. With the exponential growth of
[...] Read more.
Cloud computing has emerged as today’s most exciting computing paradigm for providing services using a shared framework, which opens a new door for solving the problems of the explosive growth of digital resource demands and their corresponding convenience. With the exponential growth of the number of data types and data size in so-called big data work, the backbone network is under great pressure due to its transmission capacity, which is lower than the growth of the data size and would seriously hinder the development of the network without an effective approach to solve this problem. In this paper, an Intelligent Aggregation based on a Content Routing (IACR) scheme for cloud computing, which could reduce the amount of data in the network effectively and play a basic supporting role in the development of cloud computing, is first put forward. All in all, the main innovations in this paper are: (1) A framework for intelligent aggregation based on content routing is proposed, which can support aggregation based content routing; (2) The proposed IACR scheme could effectively route the high aggregation ratio data to the data center through the same routing path so as to effectively reduce the amount of data that the network transmits. The theoretical analyses experiments and results show that, compared with the previous original routing scheme, the IACR scheme can balance the load of the whole network, reduce the amount of data transmitted in the network by 41.8%, and reduce the transmission time by 31.6% in the same network with a more balanced network load. Full article
Figures

Figure 1

Open AccessArticle Energy Efficient Fuzzy Adaptive Verification Node Selection-Based Path Determination in Wireless Sensor Networks
Symmetry 2017, 9(10), 220; https://doi.org/10.3390/sym9100220
Received: 7 August 2017 / Revised: 8 September 2017 / Accepted: 30 September 2017 / Published: 10 October 2017
PDF Full-text (2477 KB) | HTML Full-text | XML Full-text
Abstract
Wireless sensor networks are supplied with limited energy resources and are usually installed in unattended and unfriendly environments. These networks are also highly exposed to security attacks aimed at draining the energy of the network to render it unresponsive. Adversaries launch counterfeit report
[...] Read more.
Wireless sensor networks are supplied with limited energy resources and are usually installed in unattended and unfriendly environments. These networks are also highly exposed to security attacks aimed at draining the energy of the network to render it unresponsive. Adversaries launch counterfeit report injection attacks and false vote injection attacks through compromised sensor nodes. Several filtering solutions have been suggested for detecting and filtering false reports during the multi-hop forwarding process. However, almost all such schemes presuppose a conventional underlying protocol for data routing that do not consider the attack status or energy dissipation on the route. Each design provides approximately the equivalent resilience in terms of protection against compromised node. However, the energy consumption characteristics of each design differ. We propose a fuzzy adaptive path selection to save energy and avoid the emergence of favored paths. Fresh authentication keys are generated periodically, and these are shared with the filtering nodes to restrict compromised intermediate filtering nodes from the verification process. The scheme helps delay the emergence of hotspot problems near the base station and exhibits improved energy conserving behavior in wireless sensor networks. The proposed scheme provides an extended network lifetime and better false data filtering capacity. Full article
Figures

Figure 1

Open AccessArticle Experimental Design for Testing Local Lorentz Invariance Violations in Gravity
Symmetry 2017, 9(10), 219; https://doi.org/10.3390/sym9100219
Received: 19 September 2017 / Revised: 2 October 2017 / Accepted: 3 October 2017 / Published: 10 October 2017
PDF Full-text (530 KB) | HTML Full-text | XML Full-text
Abstract
Local Lorentz invariance is an important component of General Relativity. Testing for Local Lorentz invariance can not only probe the foundation stone of General Relativity but also help to explore the unified theory for General Relativity and quantum mechanics. In this paper, we
[...] Read more.
Local Lorentz invariance is an important component of General Relativity. Testing for Local Lorentz invariance can not only probe the foundation stone of General Relativity but also help to explore the unified theory for General Relativity and quantum mechanics. In this paper, we search the Local Lorentz invariance violation associated with operators of mass dimension d = 6 in the pure-gravity sector with short-range gravitational experiments. To enlarge the Local Lorentz invariance violation signal effectively, we design a new experiment in which the constraints of all fourteen violation coefficients may be improved by about one order of magnitude. Full article
(This article belongs to the Special Issue Violation of Lorentz Symmetry)
Figures

Figure 1

Open AccessArticle On the Fibration Defined by the Field Lines of a Knotted Class of Electromagnetic Fields at a Particular Time
Symmetry 2017, 9(10), 218; https://doi.org/10.3390/sym9100218
Received: 27 August 2017 / Revised: 5 October 2017 / Accepted: 6 October 2017 / Published: 9 October 2017
PDF Full-text (713 KB) | HTML Full-text | XML Full-text
Abstract
A class of vacuum electromagnetic fields in which the field lines are knotted curves are reviewed. The class is obtained from two complex functions at a particular instant t=0 so they inherit the topological properties of red the level curves of
[...] Read more.
A class of vacuum electromagnetic fields in which the field lines are knotted curves are reviewed. The class is obtained from two complex functions at a particular instant t = 0 so they inherit the topological properties of red the level curves of these functions. We study the complete topological structure defined by the magnetic and electric field lines at t = 0 . This structure is not conserved in time in general, although it is possible to red find special cases in which the field lines are topologically equivalent for every value of t. Full article
(This article belongs to the Special Issue Knot Theory and Its Applications)
Figures

Figure 1

Open AccessArticle Exact Finite Differences. The Derivative on Non Uniformly Spaced Partitions
Symmetry 2017, 9(10), 217; https://doi.org/10.3390/sym9100217
Received: 25 July 2017 / Revised: 30 August 2017 / Accepted: 2 September 2017 / Published: 7 October 2017
PDF Full-text (439 KB) | HTML Full-text | XML Full-text
Abstract
We define a finite-differences derivative operation, on a non uniformly spaced partition, which has the exponential function as an exact eigenvector. We discuss some properties of this operator and we propose a definition for the components of a finite-differences momentum operator. This allows
[...] Read more.
We define a finite-differences derivative operation, on a non uniformly spaced partition, which has the exponential function as an exact eigenvector. We discuss some properties of this operator and we propose a definition for the components of a finite-differences momentum operator. This allows us to perform exact discrete calculations. Full article
Figures

Figure 1

Back to Top