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Symmetry
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Symmetry in Computing Theory and Application
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Symmetry in Computing Theory and Application

A special issue of Symmetry (ISSN 2073-8994). This special issue belongs to the section "Computer".

Deadline for manuscript submissions: closed (15 February 2019) | Viewed by 82650

Special Issue Editors

Prof. Dr. Cheonshik Kim

E-Mail Website
Guest Editor
Department of Computer Engineering, Sejong University, Seoul 05006, Korea
Interests: multimedia security; multimedia signal processing; image compression; watermark technology; steganography; multimedia database
Special Issues, Collections and Topics in MDPI journals
Prof. Dr. James C.N. Yang

E-Mail Website
Guest Editor
Department of Computer Science and Information Engineering, National Dong Hwa University, Hualien 97401, Taiwan
Interests: information security; coding theory; cryptography; data hiding; steganography
Special Issues, Collections and Topics in MDPI journals
Prof. Dr. Jinsuk Baek

E-Mail
Guest Editor
Dept. of Computer Science, Winston-Salem State University, 601 S Martin Luther King Jr Dr, Winston-Salem, NC 27110, USA
Interests: Scalable Reliable Multicast Protocols; Mobile Computing; Network Security Protocols; Proxy Caching Systems; Formal Verification of Communication Protocols
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

In the computer arts and sciences, symmetry has had a profound and lasting impact. Similarly, computational treatment of symmetry plays an important role in computational sciences. Computational symmetry refers to the practice of representing, detecting, and reasoning about symmetries on computers. The intentions are to care about the computational symmetry in computer science. Recent interest in computational symmetry for computer fields, such as cryptographic theories, computational complexity, graphics, video streaming, computing algorithms, image processing, and data-hiding applications, have shown promising results. Symmetry often makes the probabilistic analysis of randomized algorithms easier and simpler.

Recently, the study of the symmetry of algorithmic or computational aspects gives us an understanding of the nature of symmetry. We invite manuscripts on all aspects of symmetry in symmetric computing theories and applications. Topics of interest include, but are not limited to:

  • Network/security technology in symmetry
  • Pattern recognition in symmetry
  • Human interfaces in symmetry
  • Image and video technology in symmetry
  • Visual secret sharing and data hiding in symmetry
  • Computing application in symmetry

Prof. Cheonshik Kim
Prof. Dr. Ching-Nung Yang
Prof. Dr. Jinsuk Baek
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Symmetry is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

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Published Papers (21 papers)

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Research

13 pages, 1194 KiB  
Article
Critical Components Identification for Service-Oriented Systems
by Xiuguo Zhang, Shuo Jiang, Xinghao Qiao, Zhiying Cao and Liangjun Zhang
Symmetry 2019, 11(3), 427; https://doi.org/10.3390/sym11030427 - 22 Mar 2019
Cited by 4 | Viewed by 3264
Abstract
Identifying critical components are of great significance to the overall reliability of service-oriented systems (SOSs). As the size of the SOS increases, identifying critical components in the process of predicting the SOS reliability can reduce the number of components that need to be [...] Read more.
Identifying critical components are of great significance to the overall reliability of service-oriented systems (SOSs). As the size of the SOS increases, identifying critical components in the process of predicting the SOS reliability can reduce the number of components that need to be predicted and shorten the prediction time. Moreover, predicting the reliability of critical components can also ensure the stability of the SOS. Therefore, we transform the relationships among service components of the SOS into a service dependency graph. Then, an improved weighted LeaderRank algorithm (IW-LeaderRank) is proposed to measure the importance of components and obtain the sequence of critical components. Through experimental analysis, the method can accurately and efficiently identify critical components in SOSs. Full article
(This article belongs to the Special Issue Symmetry in Computing Theory and Application)
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16 pages, 2651 KiB  
Article
An Efficient Knowledge-Graph-Based Web Service Recommendation Algorithm
by Zhiying Cao, Xinghao Qiao, Shuo Jiang and Xiuguo Zhang
Symmetry 2019, 11(3), 392; https://doi.org/10.3390/sym11030392 - 18 Mar 2019
Cited by 20 | Viewed by 4578
Abstract
Using semantic information can help to accurately find suitable services from a variety of available (different semantics) services, and the semantic information of Web services can be described in detail in a Web service knowledge graph. In this paper, a Web service recommendation [...] Read more.
Using semantic information can help to accurately find suitable services from a variety of available (different semantics) services, and the semantic information of Web services can be described in detail in a Web service knowledge graph. In this paper, a Web service recommendation algorithm based on knowledge graph representation learning (kg-WSR) is proposed. The algorithm embeds the entities and relationships of the knowledge graph into the low-dimensional vector space. By calculating the distance between service entities in low-dimensional space, the relationship information of services which is not considered in recommendation approaches using a collaborative filtering algorithm is incorporated into the recommendation algorithm to enhance the accurateness of the result. The experimental results show that this algorithm can not only effectively improve the accuracy rate, recall rate, and coverage rate of recommendation but also solve the cold start problem to some extent. Full article
(This article belongs to the Special Issue Symmetry in Computing Theory and Application)
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14 pages, 2030 KiB  
Article
MAIAD: A Multistage Asymmetric Information Attack and Defense Model Based on Evolutionary Game Theory
by Yu Yang, Bichen Che, Yang Zeng, Yang Cheng and Chenyang Li
Symmetry 2019, 11(2), 215; https://doi.org/10.3390/sym11020215 - 13 Feb 2019
Cited by 18 | Viewed by 3906
Abstract
With the rapid development and widespread applications of Internet of Things (IoT) systems, the corresponding security issues are getting more and more serious. This paper proposes a multistage asymmetric information attack and defense model (MAIAD) for IoT systems. Under the premise of asymmetric [...] Read more.
With the rapid development and widespread applications of Internet of Things (IoT) systems, the corresponding security issues are getting more and more serious. This paper proposes a multistage asymmetric information attack and defense model (MAIAD) for IoT systems. Under the premise of asymmetric information, MAIAD extends the single-stage game model with dynamic and evolutionary game theory. By quantifying the benefits for both the attack and defense, MAIAD can determine the optimal defense strategy for IoT systems. Simulation results show that the model can select the optimal security defense strategy for various IoT systems. Full article
(This article belongs to the Special Issue Symmetry in Computing Theory and Application)
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11 pages, 1348 KiB  
Article
MFBS: Multiple Factor Bandwidth Strategy Scheme for Anonymity Assessment
by Tianbo Lu, Meng Luo, Ru Yan and Zhimin Lin
Symmetry 2019, 11(2), 203; https://doi.org/10.3390/sym11020203 - 11 Feb 2019
Cited by 1 | Viewed by 2580
Abstract
This paper proposes a multiple factor bandwidth strategy (MFBS), an anonymity assessment scheme based on bandwidth strategy. We first analyzed the path selection algorithm mechanism based on bandwidth strategy and anonymity constraint conditions and then elaborated the overall architecture and the key module [...] Read more.
This paper proposes a multiple factor bandwidth strategy (MFBS), an anonymity assessment scheme based on bandwidth strategy. We first analyzed the path selection algorithm mechanism based on bandwidth strategy and anonymity constraint conditions and then elaborated the overall architecture and the key module design of the MFBS scheme. A detailed design was carried out so that it can be applied for the evaluation of Tor’s anonymous communication system. Finally, according to the running data in the node resource file in the anonymous network, we analyzed anonymity from different dimensions. By evaluating the bandwidth consumed by Tor in the actual network, the anonymity of the Tor could be calculated, and a more comprehensive anonymity assessment could be performed. Full article
(This article belongs to the Special Issue Symmetry in Computing Theory and Application)
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12 pages, 404 KiB  
Article
An Information Theoretically Secure E-Lottery Scheme Based on Symmetric Bivariate Polynomials
by Zhe Xia, Yining Liu, Ching-Fang Hsu and Chin-Chen Chang
Symmetry 2019, 11(1), 88; https://doi.org/10.3390/sym11010088 - 15 Jan 2019
Cited by 3 | Viewed by 3597
Abstract
E-lottery schemes have attracted much interest from both industry and academia recently, because they are not only useful to raise funds for charity institutions, but also can be used as the major building blocks to design micro-payment systems. In the literature, a number [...] Read more.
E-lottery schemes have attracted much interest from both industry and academia recently, because they are not only useful to raise funds for charity institutions, but also can be used as the major building blocks to design micro-payment systems. In the literature, a number of e-lottery schemes have been introduced over the last two decades. However, most of these schemes rely on some computational assumptions. In this paper, we introduce a novel e-lottery scheme that achieves information theoretical security. Our proposed scheme is designed using symmetric bivariate polynomials, and it satisfies the required security properties, such as correctness, unpredictability, verifiability, and robustness. Moreover, the winning number is generated in a distributed fashion, so that no trusted third party needs to be involved and the danger of a single point of failure is minimized. Full article
(This article belongs to the Special Issue Symmetry in Computing Theory and Application)
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13 pages, 7478 KiB  
Article
An Efficient Essential Secret Image Sharing Scheme Using Derivative Polynomial
by Zhen Wu, Yi-Ning Liu, Dong Wang and Ching-Nung Yang
Symmetry 2019, 11(1), 69; https://doi.org/10.3390/sym11010069 - 8 Jan 2019
Cited by 11 | Viewed by 3113
Abstract
As a popular technology in information security, secret image sharing is a method to guarantee the secret image’s security. Usually, the dealer would decompose the secret image into a series of shadows and then assign them to a number of participants, and only [...] Read more.
As a popular technology in information security, secret image sharing is a method to guarantee the secret image’s security. Usually, the dealer would decompose the secret image into a series of shadows and then assign them to a number of participants, and only a quorum of participants could recover the secret image. Generally, it is assumed that every participant is equal. Actually, due to their position in many practical applications, some participants are given special privileges. Therefore, it is desirable to give an approach to generate shadows with different priorities shadows. In this paper, an efficient essential secret image sharing scheme using a derivative polynomial is proposed. Compared with existing related works, our proposed scheme can not only create the same-sized shadows with smaller size but also removes the concatenation operation in the sharing phase. Theoretical analysis and simulations confirm the security and effectiveness of the proposed scheme. Full article
(This article belongs to the Special Issue Symmetry in Computing Theory and Application)
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31 pages, 10592 KiB  
Article
Exploring Symmetry of Binary Classification Performance Metrics
by Amalia Luque, Alejandro Carrasco, Alejandro Martín and Juan Ramón Lama
Symmetry 2019, 11(1), 47; https://doi.org/10.3390/sym11010047 - 3 Jan 2019
Cited by 14 | Viewed by 4715
Abstract
Selecting the proper performance metric constitutes a key issue for most classification problems in the field of machine learning. Although the specialized literature has addressed several topics regarding these metrics, their symmetries have yet to be systematically studied. This research focuses on ten [...] Read more.
Selecting the proper performance metric constitutes a key issue for most classification problems in the field of machine learning. Although the specialized literature has addressed several topics regarding these metrics, their symmetries have yet to be systematically studied. This research focuses on ten metrics based on a binary confusion matrix and their symmetric behaviour is formally defined under all types of transformations. Through simulated experiments, which cover the full range of datasets and classification results, the symmetric behaviour of these metrics is explored by exposing them to hundreds of simple or combined symmetric transformations. Cross-symmetries among the metrics and statistical symmetries are also explored. The results obtained show that, in all cases, three and only three types of symmetries arise: labelling inversion (between positive and negative classes); scoring inversion (concerning good and bad classifiers); and the combination of these two inversions. Additionally, certain metrics have been shown to be independent of the imbalance in the dataset and two cross-symmetries have been identified. The results regarding their symmetries reveal a deeper insight into the behaviour of various performance metrics and offer an indicator to properly interpret their values and a guide for their selection for certain specific applications. Full article
(This article belongs to the Special Issue Symmetry in Computing Theory and Application)
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13 pages, 5241 KiB  
Article
Optimal Rescue Ship Locations Using Image Processing and Clustering
by Cho-Young Jung and Sang-Lok Yoo
Symmetry 2019, 11(1), 32; https://doi.org/10.3390/sym11010032 - 2 Jan 2019
Cited by 8 | Viewed by 3667
Abstract
Currently, globalization of the world economy has also resulted in a shipping volume increase. However, this growth in maritime traffic has led to increased risk of marine accidents. These accidents have a higher probability of occurring in regions where geographical features such as [...] Read more.
Currently, globalization of the world economy has also resulted in a shipping volume increase. However, this growth in maritime traffic has led to increased risk of marine accidents. These accidents have a higher probability of occurring in regions where geographical features such as islands are present. Further, the positioning of rescue ships in a particular ocean region with a high level of maritime activity is critical for rescue operations. This paper proposes a method for determining an optimal set of locations for stationing rescue ships in an ocean region with numerous accident sites, such as in the Wando islands of South Korea. The computational challenge in this problem is identified as the positioning of numerous islands of varying sizes located in the region. Thus, the proposed method combines a clustering-based optimization method and an image processing approach that incorporates flood filling to calculate the shortest pixel value between two points in the ocean that detours around the islands. Experimental results indicate that the proposed method reduces the distance between rescue ships and each accident site by 5.0 km compared to the original rescue ship locations. Thus, rescue time is reduced. Full article
(This article belongs to the Special Issue Symmetry in Computing Theory and Application)
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16 pages, 6398 KiB  
Article
Intra Prediction of Depth Picture with Plane Modeling
by Dong-seok Lee and Soon-kak Kwon
Symmetry 2018, 10(12), 715; https://doi.org/10.3390/sym10120715 - 4 Dec 2018
Cited by 3 | Viewed by 4405
Abstract
In this paper, an intra prediction method is proposed for coding of depth pictures using plane modelling. Each pixel in the depth picture is related to the distance from a camera to an object surface, and pixels corresponding to a flat surface of [...] Read more.
In this paper, an intra prediction method is proposed for coding of depth pictures using plane modelling. Each pixel in the depth picture is related to the distance from a camera to an object surface, and pixels corresponding to a flat surface of an object form a relationship with the 2D plane surface. The plane surface can be represented by a simple equation in the 3D camera coordinate system in such a way that the coordinate system of depth pixels can be transformed to the camera coordinate system. This paper finds the parameters which define the plane surface closest to given depth pixels. The plane model is then used to predict the depth pixels on the plane surface. A depth prediction method is also devised for efficient intra prediction of depth pictures, using variable-size blocks. For prediction with variable-size blocks, the plane surface that occupies a large part of the picture can be predicted using a large block size. The simulation results of the proposed method show that the mean squared error is reduced by up to 96.6% for a block size of 4 × 4 pixels and reduced by up to 98% for a block size of 16 × 16, compared with the intra prediction modes of H.264/AVC and H.265/HEVC. Full article
(This article belongs to the Special Issue Symmetry in Computing Theory and Application)
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19 pages, 3903 KiB  
Article
FlexMonitor: A Flexible Monitoring Framework in SDN
by Binfeng Wang and Jinshu Su
Symmetry 2018, 10(12), 713; https://doi.org/10.3390/sym10120713 - 4 Dec 2018
Cited by 12 | Viewed by 3212
Abstract
Efficient network monitoring is an important basis work for network management. Generally, many management applications require accurate and timely statistics about network states at different aggregation levels at low cost, such as malicious traffic detection, traffic engineering, etc. Moreover, the network environment to [...] Read more.
Efficient network monitoring is an important basis work for network management. Generally, many management applications require accurate and timely statistics about network states at different aggregation levels at low cost, such as malicious traffic detection, traffic engineering, etc. Moreover, the network environment to be monitored is constantly changing and expanding, including not only the data center for cloud computing but also the Internet of Things (IoT) for smart urban sensing, which requires the intensive study of more fine-grained network monitoring. As is well known, the development of efficient network monitoring approaches greatly relies on a flexible monitoring framework. Software defined network (SDN) can provide dramatic advantages for network management by separating the control plane and data plane. Therefore, it is a good choice to design a flexible monitoring framework based on the advantages of SDN. However, most research works only take advantage of the centralized control feature in SDN, which leads to limited improvement in the flexibility of the monitoring framework. This paper proposes a flexible monitoring framework named FlexMonitor, which can realize greater flexibility based on not only the centralized control feature, but also the high programmability in the controller and the limited programmability in the openflow switches in SDN. There are two key parts in FlexMonitor, namely the monitoring strategy deployment part and the monitoring data collection part, which can enrich the deployment methods of monitoring strategies and increase the kinds of monitoring data sources, respectively. Based on the NetMagic platform, this monitoring framework was implemented and evaluated through realizing a distributed denial of service (DDoS) detection approach. The experimental results show that the proposed DDoS detection approach has a better detection performance compared with other related approaches as well as indirectly show that FlexMonitor can flexibly support a variety of efficient monitoring approaches. Full article
(This article belongs to the Special Issue Symmetry in Computing Theory and Application)
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16 pages, 605 KiB  
Article
Untraceable and Anonymous Mobile Payment Scheme Based on Near Field Communication
by Raylin Tso
Symmetry 2018, 10(12), 685; https://doi.org/10.3390/sym10120685 - 1 Dec 2018
Cited by 3 | Viewed by 4547
Abstract
With the developments of mobile communications, M-commerce has become increasingly popular in recent years. However, most M-commerce schemes ignore user anonymity during online transactions. As a result, user transactions may easily be traced by shops, banks or by Internet Service Providers (ISPs). To [...] Read more.
With the developments of mobile communications, M-commerce has become increasingly popular in recent years. However, most M-commerce schemes ignore user anonymity during online transactions. As a result, user transactions may easily be traced by shops, banks or by Internet Service Providers (ISPs). To deal with this problem, we introduce a new anonymous mobile payment scheme in this paper. Our new scheme has the following features: (1) Password-based authentication: authentication of users is done by low-entropy password; (2) Convenience: the new scheme is designed based on near field communication (NFC)-enabled devices and is compatible with EuroPay, MasterCard and Visa (EMV-compatible); (3) Efficiency: users do not need to have their own public/private key pairs and confidentiality is achieved via symmetric-key cryptography; (4) Anonymity: users use virtual accounts in the online shopping processes, thereby preventing attackers from obtaining user information even if the transaction is eavesdropped; (5) Untraceablity: no one (even the bank, Trusted Service Manager (TSM), or the shop) can trace a transaction and link the real identity with the buyer of a transaction; (6) Confidentiality and authenticity: all the transaction is either encrypted or signed by the sender so our new scheme can provide confidentiality and authenticity. We also present the performance and the security comparison of our scheme with other schemes. The results show that our scheme is applicable and has the most remarkable features among the existing schemes. Full article
(This article belongs to the Special Issue Symmetry in Computing Theory and Application)
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17 pages, 2221 KiB  
Article
An Iterated Hybrid Local Search Algorithm for Pick-and-Place Sequence Optimization
by Jinsheng Gao, Xiaomin Zhu, Anbang Liu, Qingyang Meng and Runtong Zhang
Symmetry 2018, 10(11), 633; https://doi.org/10.3390/sym10110633 - 13 Nov 2018
Cited by 8 | Viewed by 3179
Abstract
This paper shows the results of our study on the pick-and-place optimization problem. To solve this problem efficiently, an iterated hybrid local search algorithm (IHLS) which combines local search with integer programming is proposed. In the section of local search, the greedy algorithm [...] Read more.
This paper shows the results of our study on the pick-and-place optimization problem. To solve this problem efficiently, an iterated hybrid local search algorithm (IHLS) which combines local search with integer programming is proposed. In the section of local search, the greedy algorithm with distance weight strategy and the convex-hull strategy is developed to determine the pick-and-place sequence; in the section of integer programming, an integer programming model is built to complete the feeder assignment problem. The experimental results show that the IHLS algorithm we proposed has high computational efficiency. Furthermore, compared with the genetic algorithm and the memetic algorithm, the IHLS is less time-consuming and more suitable in solving a large-scale problem. Full article
(This article belongs to the Special Issue Symmetry in Computing Theory and Application)
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16 pages, 38027 KiB  
Article
A Novel Aesthetic QR Code Algorithm Based on Hybrid Basis Vector Matrices
by Jianfeng Lu, Weiling Cheng, Shanqing Zhang, Li Li, Zaorang Yang and Chin-Chen Chang
Symmetry 2018, 10(11), 543; https://doi.org/10.3390/sym10110543 - 25 Oct 2018
Cited by 2 | Viewed by 5061
Abstract
Recently, more and more research has focused on the beautification technology of QR (Quick Response) codes. In this paper, a novel algorithm based on the XOR (exclusive OR) mechanism of hybrid basis vector matrices and a background image synthetic strategy is proposed. The [...] Read more.
Recently, more and more research has focused on the beautification technology of QR (Quick Response) codes. In this paper, a novel algorithm based on the XOR (exclusive OR) mechanism of hybrid basis vector matrices and a background image synthetic strategy is proposed. The hybrid basis vector matrices include the reverse basis vector matrix (RBVM) and positive basis vector matrix (PBVM). Firstly, the RBVM and PBVM are obtained by the Gauss–Jordan elimination method, according to the characteristics of the RS code. Secondly, the modification of the parity area of the QR code can be applied with the XOR operation of the RBVM, and the XOR operation of the PBVM is used to change the data area of the QR code. So, the QR code can be modified to be very close to the background image without impacting the error-correction ability. Finally, in order to further decrease the difference between the QR code and the background image, a new synthesis strategy is adopted in order to obtain a better aesthetic effect. The experimental results show that it obtains a better visual effect without the sacrificing recognition rate. Full article
(This article belongs to the Special Issue Symmetry in Computing Theory and Application)
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13 pages, 6366 KiB  
Article
Evolutionary Hierarchical Sparse Extreme Learning Autoencoder Network for Object Recognition
by Yujun Zeng, Lilin Qian and Junkai Ren
Symmetry 2018, 10(10), 474; https://doi.org/10.3390/sym10100474 - 10 Oct 2018
Cited by 7 | Viewed by 3722
Abstract
Extreme learning machine (ELM), characterized by its fast learning efficiency and great generalization ability, has been applied to various object recognition tasks. When extended to the stacked autoencoder network, which is a typical symmetrical representation learning model architecture, ELM manages to realize hierarchical [...] Read more.
Extreme learning machine (ELM), characterized by its fast learning efficiency and great generalization ability, has been applied to various object recognition tasks. When extended to the stacked autoencoder network, which is a typical symmetrical representation learning model architecture, ELM manages to realize hierarchical feature extraction and classification, which is what deep neural networks usually do, but with much less training time. Nevertheless, the input weights and biases of the hidden nodes in ELM are generated according to a random distribution and may lead to the occurrence of non-optimal and redundant parameters that deteriorate discriminative features, which will have a bad influence on the final classification effect. In this paper, a novel sparse autoencoder derived from ELM and differential evolution is proposed and integrated into a hierarchical hybrid autoencoder network to accomplish the end-to-end learning with raw visible light camera sensor images and applied to several typical object recognition problems. Experimental results show that the proposed method is able to obtain competitive or better performance than current relevant methods with acceptable or less time consumption. Full article
(This article belongs to the Special Issue Symmetry in Computing Theory and Application)
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15 pages, 4237 KiB  
Article
Vertex Labeling and Routing for Farey-Type Symmetrically-Structured Graphs
by Wenchao Jiang, Yinhu Zhai, Zhigang Zhuang, Paul Martin, Zhiming Zhao and Jia-Bao Liu
Symmetry 2018, 10(9), 407; https://doi.org/10.3390/sym10090407 - 17 Sep 2018
Cited by 3 | Viewed by 5716
Abstract
The generalization of Farey graphs and extended Farey graphs all originate from Farey graphs. They are simultaneously scale-free and small-world. A labeling of the vertices for them are proposed here. All of the shortest paths between any two vertices in these two graphs [...] Read more.
The generalization of Farey graphs and extended Farey graphs all originate from Farey graphs. They are simultaneously scale-free and small-world. A labeling of the vertices for them are proposed here. All of the shortest paths between any two vertices in these two graphs can be determined only on their labels. The number of shortest paths between any two vertices is the product of two Fibonacci numbers; it is increasing almost linearly with the order or size of the graphs. However, the label-based routing algorithm runs in logarithmic time O(logn). Our efficient routing protocol for Farey-type models should help contribute toward the understanding of several physical dynamic processes. Full article
(This article belongs to the Special Issue Symmetry in Computing Theory and Application)
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15 pages, 436 KiB  
Article
Effective Blind Frequency Offset Estimation Scheme for BST-OFDM Based HDTV Broadcast Systems
by Yong-An Jung and Young-Hwan You
Symmetry 2018, 10(9), 379; https://doi.org/10.3390/sym10090379 - 3 Sep 2018
Cited by 1 | Viewed by 3141
Abstract
The integrated services digital broadcasting-terrestrial (ISDB-T) system is designed in order to accommodate high-quality video/audio and multimedia services, using band segmented transmission orthogonal frequency division multiplexing (BST-OFDM) scheme. In the ISDB-T system, the pilot configuration varies depending on whether a segment uses a [...] Read more.
The integrated services digital broadcasting-terrestrial (ISDB-T) system is designed in order to accommodate high-quality video/audio and multimedia services, using band segmented transmission orthogonal frequency division multiplexing (BST-OFDM) scheme. In the ISDB-T system, the pilot configuration varies depending on whether a segment uses a coherent or differential modulation. Therefore, it is necessary to perform a joint estimation of carrier frequency offset (CFO) and sampling frequency offset (SFO) independent of the segment format in the ISDB-T system. The goal is to complete those synchronization tasks while considering an information-carrying transmission and multiplexing configuration control (TMCC) signal as pilot symbols. It is demonstrated through numerical simulations that the differential BPSK-modulated TMCC information can be efficiently used for a least-squares estimation of CFO and SFO, offering an acceptable performance. Full article
(This article belongs to the Special Issue Symmetry in Computing Theory and Application)
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16 pages, 25393 KiB  
Article
A Modified Dolph-Chebyshev Type II Function Matched Filter for Retinal Vessels Segmentation
by Dhimas Arief Dharmawan, Boon Poh Ng and Susanto Rahardja
Symmetry 2018, 10(7), 257; https://doi.org/10.3390/sym10070257 - 3 Jul 2018
Cited by 6 | Viewed by 3352
Abstract
In this paper, we present a new unsupervised algorithm for retinal vessels segmentation. The algorithm utilizes a directionally sensitive matched filter bank using a modified Dolph-Chebyshev type II basis function and a new method to combine the matched filter bank’s responses. Fundus images [...] Read more.
In this paper, we present a new unsupervised algorithm for retinal vessels segmentation. The algorithm utilizes a directionally sensitive matched filter bank using a modified Dolph-Chebyshev type II basis function and a new method to combine the matched filter bank’s responses. Fundus images from the DRIVE and STARE databases, as well as high-resolution fundus images from the HRF database, are utilized to validate the proposed algorithm. The results that we achieve on the three databases (DRIVE: Sensitivity = 0.748, F1-score = 0.786, G-score = 0.856, Matthews Correlation Coefficient = 0.758; STARE: Sensitivity = 0.793, F1-score = 0.780, G-score = 0.877, Matthews Correlation Coefficient = 0.756; HRF: Sensitivity = 0.804, F1-score = 0.764, G-score = 0.883, Matthews Correlation Coefficient = 0.741) are higher than many other competing methods. Full article
(This article belongs to the Special Issue Symmetry in Computing Theory and Application)
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16 pages, 1790 KiB  
Article
Lossless and Efficient Polynomial-Based Secret Image Sharing with Reduced Shadow Size
by Xuan Zhou, Yuliang Lu, Xuehu Yan, Yongjie Wang and Lintao Liu
Symmetry 2018, 10(7), 249; https://doi.org/10.3390/sym10070249 - 1 Jul 2018
Cited by 34 | Viewed by 3540
Abstract
Thien-and-Lin’s polynomial-based secret image sharing (PSIS) is utilized as the basic method to achieve PSISs with better performances, such as meaningful shares, two-in-one property and shares with different priorities. However, this (k,n) threshold PSIS cannot achieve lossless recovery for [...] Read more.
Thien-and-Lin’s polynomial-based secret image sharing (PSIS) is utilized as the basic method to achieve PSISs with better performances, such as meaningful shares, two-in-one property and shares with different priorities. However, this (k,n) threshold PSIS cannot achieve lossless recovery for pixel values more than 250. Furthermore, current solutions to lossless recovery for PSIS have several natural drawbacks, such as large computational costs and random pixel expansion. In this paper, a lossless and efficient (k,n) threshold PSIS scheme with reduced shadow size is presented. For lossless recovery and efficiency, two adjacent pixels are specified as a secret value, the prime in the sharing polynomial is replaced with 65,537, and then the additional screening operation can ensure each shared value in the range [0,65,535]. To reduce shadows size and improve security, only the first k−1 coefficients are embedded with secret values and the last coefficient is assigned randomly. To prevent the leakage of secrets, generalized Arnold permutation with special key generating strategy is performed on the secret image prior to sharing process without key distribution. Both theoretical analyses and experiments are conducted to demonstrate the effectiveness of the proposed scheme. Full article
(This article belongs to the Special Issue Symmetry in Computing Theory and Application)
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23 pages, 2644 KiB  
Article
Weak Fault Detection for Gearboxes Using Majorization–Minimization and Asymmetric Convex Penalty Regularization
by Qing Li and Steven Y. Liang
Symmetry 2018, 10(7), 243; https://doi.org/10.3390/sym10070243 - 26 Jun 2018
Cited by 8 | Viewed by 3236
Abstract
It is a primary challenge in the fault diagnosis community of the gearbox to extract the weak fault features under heavy background noise and nonstationary conditions. For this purpose, a novel weak fault detection approach based on majorization–minimization (MM) and asymmetric convex penalty [...] Read more.
It is a primary challenge in the fault diagnosis community of the gearbox to extract the weak fault features under heavy background noise and nonstationary conditions. For this purpose, a novel weak fault detection approach based on majorization–minimization (MM) and asymmetric convex penalty regularization (ACPR) is proposed in this paper. The proposed objective cost function (OCF) consisting of a signal-fidelity term, and two parameterized penalty terms (i.e., one is an asymmetric nonconvex penalty regularization term, and another is a symmetric nonconvex penalty regularization term).To begin with, the asymmetric and symmetric penalty functions are established on the basis of an L1-norm model, then, according to the splitting idea, the majorizer of the symmetric function and the majorizer of the asymmetric function are respectively calculated via the MM algorithm. Finally, the MM is re-introduced to solve the proposed OCF. As examples, the effectiveness and reliability of the proposed method is verified through simulated data and gearbox experimental real data. Meanwhile, a comparison with the state of-the-art methods is illustrated, including nonconvex penalty regularization (NCPR) and L1-norm fused lasso optimization (LFLO) techniques, the results indicate that the gear chipping characteristic frequency 13.22 Hz and its harmonic (2f, 3f, 4f and 5f) can be identified clearly, which highlights the superiority of the proposed approach. Full article
(This article belongs to the Special Issue Symmetry in Computing Theory and Application)
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15 pages, 4767 KiB  
Article
Bayer Image Demosaicking Using Eight-Directional Weights Based on the Gradient of Color Difference
by Yizheng Liu, Chengyou Wang, Hongming Zhao, Jiayang Song and Shiyue Chen
Symmetry 2018, 10(6), 222; https://doi.org/10.3390/sym10060222 - 14 Jun 2018
Cited by 1 | Viewed by 5448
Abstract
In this paper, we propose a new demosaicking algorithm which uses eight-directional weights based on the gradient of color difference (EWGCD) for Bayer image demosaicking. To obtain the interpolation of green (G) pixels, the eight-directional G pixel values are first estimated in red [...] Read more.
In this paper, we propose a new demosaicking algorithm which uses eight-directional weights based on the gradient of color difference (EWGCD) for Bayer image demosaicking. To obtain the interpolation of green (G) pixels, the eight-directional G pixel values are first estimated in red (R)/blue (B) pixels. This estimate is used to calculate the color difference in R/B pixels of the Bayer image in diagonal directions. However, in horizontal and vertical directions, the new estimated G pixels are defined to obtain the color difference. The eight-directional weights of estimated G pixels can be obtained by considering the gradient of the color difference and the gradient of the RGB pixels of the Bayer image. Therefore, the eight-directional weighted values and the first estimated G pixel values are combined to obtain the full G image. Compared with six similar algorithms using the same eighteen McMaster images, the results of the experiment demonstrate that the proposed algorithm has a better performance not only in the subjective visual measurement but also in the assessments of peak signal-to-noise ratio (PSNR) and structural similarity (SSIM) index measurement. Full article
(This article belongs to the Special Issue Symmetry in Computing Theory and Application)
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12 pages, 425 KiB  
Article
A Novel Comparison of Probabilistic Hesitant Fuzzy Elements in Multi-Criteria Decision Making
by Chenyang Song, Zeshui Xu and Hua Zhao
Symmetry 2018, 10(5), 177; https://doi.org/10.3390/sym10050177 - 21 May 2018
Cited by 33 | Viewed by 3327
Abstract
The probabilistic hesitant fuzzy element is a common tool to deal with multi-criteria decision-making problems when the decision makers are irresolute in providing their evaluations. The existing methods for ranking probabilistic hesitant fuzzy elements are limited and not reasonable in practical applications. The [...] Read more.
The probabilistic hesitant fuzzy element is a common tool to deal with multi-criteria decision-making problems when the decision makers are irresolute in providing their evaluations. The existing methods for ranking probabilistic hesitant fuzzy elements are limited and not reasonable in practical applications. The main purpose of this paper is to find a more precise and appropriate comparison method so that we can deal with multi-criteria decision-making problems more efficiently. We first propose a chart technique to analyze the structure of a probabilistic hesitant fuzzy element. After that, we propose a novel possibility degree formula to rank probabilistic hesitant fuzzy elements. Last but not least, we provide a useful process to solve the actual multi-criteria decision-making problems, and make a real case study which demonstrates that our method is feasible and reliable. Full article
(This article belongs to the Special Issue Symmetry in Computing Theory and Application)
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