Subjects -> MANUFACTURING AND TECHNOLOGY (Total: 362 journals)
    - CERAMICS, GLASS AND POTTERY (31 journals)
    - MACHINERY (34 journals)
    - MANUFACTURING AND TECHNOLOGY (223 journals)
    - METROLOGY AND STANDARDIZATION (5 journals)
    - PACKAGING (19 journals)
    - PAINTS AND PROTECTIVE COATINGS (4 journals)
    - PLASTICS (42 journals)
    - RUBBER (4 journals)

PLASTICS (42 journals)

Showing 1 - 41 of 41 Journals sorted alphabetically
ACS Applied Polymer Materials     Hybrid Journal   (Followers: 15)
Acta Polymerica     Hybrid Journal   (Followers: 10)
Additives for Polymers     Full-text available via subscription   (Followers: 22)
Advanced Industrial and Engineering Polymer Research     Open Access   (Followers: 5)
Advances in Polymer Technology     Open Access   (Followers: 15)
Chinese Journal of Polymer Science     Hybrid Journal   (Followers: 13)
Cirugia Plastica Ibero-Latinoamericana     Open Access  
Current Applied Polymer Science     Hybrid Journal   (Followers: 3)
European Polymer Journal     Hybrid Journal   (Followers: 46)
High Performance Polymers     Hybrid Journal   (Followers: 1)
International Journal of Biobased Plastics     Open Access   (Followers: 1)
International Journal of Polymeric Materials     Hybrid Journal   (Followers: 6)
International Polymer Processing     Full-text available via subscription   (Followers: 2)
Iranian Journal of Polymer Science and Technology     Open Access   (Followers: 1)
Journal of Applied Polymer Science     Hybrid Journal   (Followers: 211)
Journal of Cellular Plastics     Hybrid Journal  
Journal of Elastomers and Plastics     Hybrid Journal   (Followers: 1)
Journal of Inorganic and Organometallic Polymers and Materials     Hybrid Journal   (Followers: 11)
Journal of Plastic Film and Sheeting     Hybrid Journal   (Followers: 1)
Journal of Polymer Research     Hybrid Journal   (Followers: 8)
Journal of Polymer Science Part C : Polymer Letters     Hybrid Journal   (Followers: 6)
Journal of Polymers and the Environment     Hybrid Journal   (Followers: 1)
Majalah Kulit, Karet, dan Plastik     Open Access  
Microplastics and Nanoplastics     Open Access   (Followers: 2)
Plasmas and Polymers     Hybrid Journal  
Plastic and Polymer Technology     Open Access   (Followers: 42)
Plastic and Reconstructive Surgery     Hybrid Journal   (Followers: 37)
Plastics Engineering     Partially Free   (Followers: 4)
Polymer     Hybrid Journal   (Followers: 248)
Polymer Bulletin     Hybrid Journal   (Followers: 9)
Polymer Engineering & Science     Hybrid Journal   (Followers: 16)
Polymer Science Series B     Hybrid Journal   (Followers: 5)
Polymer Science Series C     Hybrid Journal   (Followers: 4)
Polymer Science Series D     Hybrid Journal   (Followers: 4)
Polymer Science, Series A     Hybrid Journal   (Followers: 4)
Polymer-Plastics Technology and Materials     Hybrid Journal   (Followers: 5)
Polymers and Polymer Composites     Hybrid Journal   (Followers: 5)
Polymers from Renewable Resources     Hybrid Journal  
Progress in Rubber, Plastics and Recycling Technology     Hybrid Journal   (Followers: 2)
Reinforced Plastics     Full-text available via subscription   (Followers: 18)
SPE Polymers     Open Access   (Followers: 1)
Similar Journals
Journal Cover
Polymer Science, Series A
Journal Prestige (SJR): 0.272
Citation Impact (citeScore): 1
Number of Followers: 4  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 0965-545X - ISSN (Online) 1555-6107
Published by Springer-Verlag Homepage  [2654 journals]
  • IEEE Transactions on Broadcasting

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      Abstract: Presents a listing of the editorial board, board of governors, current staff, committee members, and/or society editors for this issue of the publication.
      PubDate: Sept. 2021
      Issue No: Vol. 67, No. 3 (2021)
       
  • IEEE Transactions on Broadcasting information for authors

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      Abstract: These instructions give guidelines for preparing papers for this publication. Presents information for authors publishing in this journal.
      PubDate: Sept. 2021
      Issue No: Vol. 67, No. 3 (2021)
       
  • Broadcast Core-Network: Converging Broadcasting With the Connected World

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      Authors: Jon Montalban;Rufino Cabrera;Eneko Iradier;Pablo Angueira;Yiyan Wu;Liang Zhang;Wei Li;Zhihong Hong;
      Pages: 558 - 569
      Abstract: The new ways to consume and deliver media content in a wireless environment have led to a significant increase in the demand for spectrum resources. In addition, the arrival of next-generation wireless communication technologies has encouraged the creating of new verticals targeting novel applications, such as industry IoT, e-health, distance learning, smart city, smart-metering. All these new use cases are centred on an IP-based infrastructure. A promising alternative to satisfy the demand for resources is to incorporate a new delivery mechanism that can alleviate the congestion of classical cell-based point-to-point broadband wireless infrastructures. The best-positioned candidate is the next-generation Digital Terrestrial Television system, which offers a very spectrum efficient one-to-many PHY, and for the first time, native IP support. In ATSC 3.0, the whole system was designed with an IP-centric view, whereas DVB has created standards to deliver services to generic IP devices (DVB-I). Nevertheless, there is still a last missing piece to bring the broadcast infrastructure to the IP-connected world: a Broadcast Core Network (BCN). In this paper, the basics of a BCN are presented with new use cases that are attractive to Broadcast Network Operator (BNO). A possible roadmap towards implementation is described, and a service-based architecture for a BCN is presented and discussed.
      PubDate: Sept. 2021
      Issue No: Vol. 67, No. 3 (2021)
       
  • Integrated Inter-Tower Wireless Communications Network for Terrestrial
           Broadcasting and Multicasting Systems

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      Authors: Wei Li;Liang Zhang;Yiyan Wu;Zhihong Hong;Sébastien Laflèche;Sung-Ik Park;Sunhyoung Kown;Sungjun Ahn;Namho Hur;Eneko Iradier;Iñigo Bilbao;Jon Montalban;Pablo Angueira;
      Pages: 570 - 581
      Abstract: This paper describes systems, devices, and methods to implement a bi-directional integrated inter-tower wireless communications network (IITWCN). The described technology can be implemented in combination with the Broadcast Core Network (BCN) in next generation broadcast eco-system and, therefore, support new business cases for broadcast operators such as the delivery of flexible datacasting services or support broadcast or point-to-point Internet services. The introduced bi-directional inter-tower communications network (ITCN) extends the previous unidirectional in-band distribution links (IDL) and adopts the on-channel repeater (OCR) as a simplified backhaul solution in single frequency networks (SFN). The concept of the coordinated ITCN is also presented, aiming at future broadcast Internet services. The ITCN provides a scalable and configurable network solution embedded in a broadcast system, which becomes independent from any non-broadcasting telecommunication infrastructure. The described technology partially relies on the infrastructure of the underlying broadcast/multicast network, using the allocated service channels without requiring additional frequency bands or a separate frequency band. The bi-directional inter-transmitter communication links are therefore referred to as integrated transmission links and the corresponding network as an integrated network.
      PubDate: Sept. 2021
      Issue No: Vol. 67, No. 3 (2021)
       
  • MBSFN or SC-PTM: How to Efficiently Multicast/Broadcast

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      Authors: Yizhe Zhang;Dazhi He;Yin Xu;Yunfeng Guan;Wenjun Zhang;
      Pages: 582 - 592
      Abstract: In Multimedia Broadcast/Multicast Service(MBMS), Multicast/Broadcast Single Frequency Network (MBSFN) and Single-cell Point-to-multipoint Network (SC-PTM) are two essential ways to organize networks to provide multicast services. MBSFN shows its unique advantage of enhancing signals at the boundary of two cells, however, highly requiring synchronization of symbols. SC-PTM shows the advantage of the flexibility on the network deployment. The comparison and complementarity of these two modes are explored. In this paper, we analyze the reception performance of MBSFN and SC-PTM from multiple perspectives. We first compare the successful transmission probability (STP) of MBSFN with that of SC-PTM. Then, we consider optimal power control problems in MBSFN and SC-PTM. The corresponding power control optimization problems are with fraction and max-min forms and solved by the Dinkelbach algorithm. Furthermore, we propose a joint mode-selection and power-control method in the hybrid mode of MBSFN and SC-PTM, where each cell could select the multicast mode from MBSFN and SC-PTM. This is a mixed-integer nonlinear programming (MINLP) problem and solved by the concave-convex procedure (CCCP) and the Dinkelbach algorithm. To further improve the throughput, the appropriate successful reception proportion is selected under the opportunistic multicast. Finally, the numerical simulations show the performance of our algorithms and compare the throughput of two modes, which verify our analysis.
      PubDate: Sept. 2021
      Issue No: Vol. 67, No. 3 (2021)
       
  • Efficient Management of Multicast Traffic in Directional mmWave Networks

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      Authors: Nadezhda Chukhno;Olga Chukhno;Sara Pizzi;Antonella Molinaro;Antonio Iera;Giuseppe Araniti;
      Pages: 593 - 605
      Abstract: Multicasting is becoming more and more important in the Internet of Things (IoT) and wearable applications (e.g., high definition video streaming, virtual reality gaming, public safety, among others) that require high bandwidth efficiency and low energy consumption. In this regard, millimeter wave (mmWave) communications can play a crucial role to efficiently disseminate large volumes of data as well as to enhance the throughput gain in fifth-generation (5G) and beyond networks. There are, however, challenges to face in view of providing multicast services with high data rates under the conditions of short propagation range caused by high path loss at mmWave frequencies. Indeed, the strong directionality required at extremely high frequency bands excludes the possibility of serving all multicast users via a single transmission. Therefore, multicasting in directional systems consists of a sequence of beamformed transmissions to serve all multicast group members, subgroup by subgroup. This paper focuses on multicast data transmission optimization in terms of throughput and, hence, of the energy efficiency of resource-constrained devices such as wearables, running their resource-hungry applications. In particular, we provide a means to perform the beam switching and propose a radio resource management (RRM) policy that can determine the number and width of the beams required to deliver the multicast content to all interested users. Achieved simulation results show that the proposed RRM policy significantly improves network throughput with respect to benchmark approaches. It also achieves a high gain in energy efficiency over unicast and multicast with fixed predefined beams.
      PubDate: Sept. 2021
      Issue No: Vol. 67, No. 3 (2021)
       
  • A Model for User Interface Adaptation of Multi-Device Media Services

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      Authors: Ana Domínguez;Julián Flórez;Alberto Lafuente;Stefano Masneri;Iñigo Tamayo;Mikel Zorrilla;
      Pages: 606 - 618
      Abstract: In the current audiovisual arena the user has the chance to consume different contents at once across multiple Internet-connected devices, such as smart TV, smartphone, tablet or laptop. However, few existing solutions are able to dynamically adapt a multitude of contents as a single experience across multi-device contexts and the existing ones are very scenario specific. To address this gap, we propose a general multi-device adaptation model, that provides a framework for building adaptive User Interfaces (UIs) for multi-screen applications under the Create Once and Publish Everywhere (COPE) concept. Hybrid broadcast-broadband TV is a reference application field for the adaptation model. However, our model is universal in the sense that it can be applied to any kind of content, device or user; in different multi-device scenarios; and in other fields such as industry or crisis management. The proposed model is an outcome of an extensive research that arose from a previous multi-device media service deployment with broadcasters, which helped to identify a set of guidelines and improvements. In order to meet this goal, the UI is formalised as a set of elements including components, devices and layouts and the adaptation process is modelled as a function of these components. Additionally, an evaluation model is provided which allows the validation of the approach in terms of quality, efficiency and universality. The tests carried out show that the model provides efficient solutions which, although they are suboptimal, have enough quality to meet the expectations of broadcasters and researchers in different scenarios.
      PubDate: Sept. 2021
      Issue No: Vol. 67, No. 3 (2021)
       
  • Rate-Splitting for Multicarrier Multigroup Multicast: Precoder Design and
           Error Performance

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      Authors: Hongzhi Chen;De Mi;Tong Wang;Zheng Chu;Yin Xu;Dazhi He;Pei Xiao;
      Pages: 619 - 630
      Abstract: Employing multi-antenna rate-splitting (RS) at the transmitter and successive interference cancellation (SIC) at the receivers, has emerged as a powerful transceiver strategy for multi-antenna networks. In this paper, we design RS precoders for an overloaded multicarrier multigroup multicast downlink system, and analyse the error performance. RS splits each group message into degraded and designated parts. The degraded parts are combined and encoded into a degraded stream, while the designated parts are encoded in designated streams. All streams are precoded and superimposed in a non-orthogonal fashion before being transmitted over the same time-frequency resource. We first derive the optimized RS-based precoder, where the design philosophy is to achieve a fair user group rate for the considered scenario by solving a joint max-min fairness and sum subcarrier rate optimization problem. Comparing with other precoding schemes including the state-of-the-art multicast transmission scheme, we show that the RS precoder outperforms its counterparts in terms of the fairness rate, with Gaussian signalling, i.e., idealistic assumptions. Then we integrate the optimized RS precoder into a practical transceiver design for link-level simulations (LLS), with realistic assumptions such as finite alphabet inputs and finite code block length. The performance metric becomes the coded bit error rate (BER). In the system under study, low-density parity-check (LDPC) encoding is applied at the transmitter, and iterative soft-input soft-output detection and decoding are employed at the successive interference cancellation based receiver, which completes the LLS processing chain and helps to generate the coded error performance results which validate the effectiveness of the proposed RS precoding scheme compared with benchmark schemes, in terms of the error performance. More importantly, we unveil the corresponding relations between the achievable rate in the idealistic case and coded BER i- the realistic case, e.g., with finite alphabet input, for the RS precoded multicarrier multigroup multicast scenario.
      PubDate: Sept. 2021
      Issue No: Vol. 67, No. 3 (2021)
       
  • A Novel Coordinated Multipoint Scheme With Zero Guard Interval for ATSC
           3.0 Single Frequency Networks

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      Authors: Nazli Ahmad Khan Beigi;Mohammad Reza Soleymani;
      Pages: 631 - 641
      Abstract: Advanced Television Systems Committee (ATSC) has issued ATSC 3.0 as the standard for the next-generation of Digital Terrestrial Television (DTT) broadcasting. ATSC 3.0 introduces several new features including Layered Division Multiplexing (LDM) that is a form of Non-Orthogonal Multiple Access (NOMA). ATSC 3.0 supports the legacy Single Frequency Networks (SFN), where the Guard Interval (GI) is considered to overcome the multipath as well as the asynchronous reception from different transmitters. Considering the huge distances between the DTT broadcasters, the GI overhead could be comparable to the data size, making the control/data ratio unfavorable. This paper proposes the association of Coordinated MultiPoint (CoMP) in SFN with NOMA-LDM. A novel formation of the channel matrix is provided that jointly includes the asynchronous channel’s cross correlations for further joint detection of the signals at the receiver. The purpose is to enhance the coverage and spectral efficiency while avoiding hectic guard intervals or directional antennas. The capacity region is derived in an information theoretic framework based on exploiting the asynchronous channels’ memory and correlation. We show that the spectral efficiency can exceed that of the non-coordinating schemes, provided that the proper receiver is equipped with the proposed channel matrix formation. Our extensive simulations validate that our proposed association of CoMP-SFN with NOMA-LDM provides a considerable boost in the coverage and channel reliability, while increasing the spectral and power efficiency.
      PubDate: Sept. 2021
      Issue No: Vol. 67, No. 3 (2021)
       
  • An Imaginary Interference-Free Method for MIMO Precoding in FBMC/OQAM
           Systems

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      Authors: You Xu;Zhongxiu Feng;Jing Zou;Dejin Kong;Yu Xin;Tao Jiang;
      Pages: 642 - 650
      Abstract: Due to the imaginary interference, the filter bank multi-carrier with offset quadrature amplitude modulation (FBMC/OQAM) performs poor in context of multiple-input multiple-output (MIMO) communication scenarios. In this article, we propose an imaginary interference-free method for FBMC/OQAM, which is appropriate for both of the subcarrier-based singular valued decomposition (SVD) precoding as well as subband-based precoding with codebook schemes. Specifically, the critical design utilizes a repeated block with the reverse arrangement of symbols. Moreover, we investigate the leakage of imaginary interference of the precoding MIMO-FBMC/OQAM system under frequency selective channel. It is found that these developed precoding solutions may particularly inhibit the inter-carrier interference (ICI) via the meticulous designed symbols block. Theoretical analysis and simulation results over different frequency selective channels validate that the proposed precoding schemes are capable of providing considerable performance gains over the conventional schemes in terms of bit error rate (BER).
      PubDate: Sept. 2021
      Issue No: Vol. 67, No. 3 (2021)
       
  • Blind Classification of Error-Correcting Codes for Enhancing Spectral
           Efficiency of Wireless Networks

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      Authors: Soonhee Kwon;Dong-Joon Shin;
      Pages: 651 - 663
      Abstract: Error-correcting codes (ECCs) are essential to improve the reliability of digital communication systems. ECCs can detect or correct the errors by introducing and utilizing the systematic parity check bits, which however deteriorate the spectral efficiency of digital communication systems. In order to enhance the spectral efficiency, the used ECC may be blindly detected at the receiver. Also, blind detection of ECCs is important in the broadcasting systems. Recently, blind detection schemes of ECCs have been actively studied and most of them assume that the receiver knows which type of ECC, a block code or a non-block code, is used. However, in real situations, blind classification about whether the ECC is a block code or a non-block code should be performed first. In this paper, a blind classification scheme of ECCs in a noisy environment is proposed, which does not require the knowledge of parameters of the used ECC. The proposed scheme classifies whether the received bit-stream is encoded by an ECC or not, and if it is determined that the received bit-stream is encoded, the proposed scheme further classifies whether the used ECC is a block code or a non-block code. Also, a novel rank calculation scheme of the intercepted matrix is proposed by performing a probabilistic analysis of random row permutation for the intercepted matrix. Based on this analysis, the minimum number of random row permutations is theoretically derived for guaranteeing correct rank calculation with probability at least $beta $ . Through various simulations, it is shown that the proposed rank calculation and blind classification schemes outperform the existing rank calculation and blind classification schemes. Furthermore, it is verified that the performance gap between the proposed schemes and the existing schemes becomes larger as $beta $ is incr-ased.
      PubDate: Sept. 2021
      Issue No: Vol. 67, No. 3 (2021)
       
  • A Machine Learning Resource Allocation Solution to Improve Video Quality
           in Remote Education

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      Authors: Ioan-Sorin Comşa;Andreea Molnar;Irina Tal;Per Bergamin;Gabriel-Miro Muntean;Cristina Hava Muntean;Ramona Trestian;
      Pages: 664 - 684
      Abstract: The current global pandemic crisis has unquestionably disrupted the higher education sector, forcing educational institutions to rapidly embrace technology-enhanced learning. However, the COVID-19 containment measures that forced people to work or stay at home, have determined a significant increase in the Internet traffic that puts tremendous pressure on the underlying network infrastructure. This affects negatively content delivery and consequently user perceived quality, especially for video-based services. Focusing on this problem, this paper proposes a machine learning-based resource allocation solution that improves the quality of video services for increased number of viewers. The solution is deployed and tested in an educational context, demonstrating its benefit in terms of major quality of service parameters for various video content, in comparison with existing state of the art. Moreover, a discussion on how the technology is helping to mitigate the effects of massively increasing Internet traffic on the video quality in an educational context is also presented.
      PubDate: Sept. 2021
      Issue No: Vol. 67, No. 3 (2021)
       
  • Speech Quality Improvement of Commercial Flat Screen TV-Sets

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      Authors: Arianna Astolfi;Fabrizio Riente;Louena Shtrepi;Alessio Carullo;Leonardo Scopece;Marco Masoero;
      Pages: 685 - 695
      Abstract: This work deals with the improvement of perceived speech quality of flat screen TV-sets on the various broadcasting platforms of the Italian radio and TV broadcasting company Rai. It is well known that the reduced thickness of flat TVs implied a degradation of the audio quality due to the adoption of miniaturised and cheap loudspeakers compared to the ones in the former Cathode Ray Tube televisions. The research activity gave rise to a Transfer Function (TF), which modifies in real-time the frequency spectrum of the audio signal from the TV station before the transmission to the broadcasting tower. In this way, the final users receive the processed audio signal without the need of additional hardware. A Digital Audio Optimizer dynamically equalizes the sound level, boosting the audio signal towards a flat frequency response without any increase in the loudness levels. Given that the majority of the broadcasted audio signals have speech or singing contents, the TF boosts the speech level in the frequency range that is more important for speech intelligibility, i.e., between 1 kHz and 4 kHz. Subjective evaluations of the proposed TF have been carried out in a laboratory in compliance with the standard ITU-R BS.1116. Three different commercial TV-set models, 30 audio excerpts from video tracks divided into the three genres Speech, Sing and Music, and Sport, and 72 subjects aged between 21 and 53 years, were part of the study. Overall, the perceived improvement in the audio quality compared to the non-processed signal was 25.3% on average among the three TV-set models and the three genres. In order to estimate the perceived improvement directly from the audio signal, regression analyses have been performed, which allow the estimation of subjective outcomes from objective indexes based on intensity features and frequency content of the signal, with standard errors between 10% and 14%.
      PubDate: Sept. 2021
      Issue No: Vol. 67, No. 3 (2021)
       
  • Full-Reference Quality Assessment for Screen Content Images Based on the
           Concept of Global-Guidance and Local-Adjustment

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      Authors: Jiachen Yang;Zilin Bian;Yang Zhao;Wen Lu;Xinbo Gao;
      Pages: 696 - 709
      Abstract: Benefiting from the development of multimedia communication terminals, the visual content presented to people on mobile devices is no longer a single form, but contains text, natural images, and other computer-generated graphics, which is called screen content images (SCIs). Inspired by the different visual stimuli that text and images bring to human eyes and the concept of global-guidance and local-adjustment, we design a novel full-reference image quality assessment (IQA) model using the structural features of the text, the perceptual features of pictures, and a score integration model (SPSIM) to evaluate SCIs quality. Firstly, we split the SCIs into textual and pictorial regions through a fully convolutional network (FCN) to conduct separate analyses. For textual regions, we take advantage of narrow edge extensions and high edge steps as structural features to compute the textual score. For pictorial regions, we extract the just noticeable difference (JND) features, which measure the human eye’s ability to detect distortion as perceptual features to calculate the pictorial score. Finally, an innovative score integration method based on the global-guidance and local-adjustment is designed to better analyze the relationship between the above regional scores and the whole global SCIs score. Abundant experiments in SCIs databases have shown that the SPSIM model can achieve better consistency with the human eyes system (HVS) in predicting the visual quality of SCIs.
      PubDate: Sept. 2021
      Issue No: Vol. 67, No. 3 (2021)
       
  • Early Intra CU Size Decision for Versatile Video Coding Based on a Tunable
           Decision Model

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      Authors: Yue Li;Gaobo Yang;Yun Song;Hanling Zhang;Xiangling Ding;Dengyong Zhang;
      Pages: 710 - 720
      Abstract: Versatile video coding (VVC) further improves video coding gain by introducing a new Quad-tree (QT) with nested multi-type tree (QTMT) partition structure, which includes QT partition, horizontal and vertical binary-tree (BT) partition, and horizontal and vertical ternary-tree (TT) partition. However, the coding gain is achieved at the cost of drastically increased coding complexity. We propose an early intra coding unit (CU) size partition method for VVC based on a tunable decision model. The distortion of the CU is firstly obtained by the difference between the original luminance pixel and the predicted one. By exploiting the distortion, two decision models are established for the early skipping of BT and TT partition for each CU, respectively. Then, a tunable decision model is presented to achieve different trade-off between encoding loss and complexity reduction. Extensive experimental results show that the proposed approach reduces the encoding time ranging from 22.6% to 67.6% with the BD-Rate increase ranging from 0.56% to 2.61%. It is also suitable for parallel implementation by exploiting the pipeline structure of the VVC encoder due to its independency with neighboring CU blocks.
      PubDate: Sept. 2021
      Issue No: Vol. 67, No. 3 (2021)
       
  • Low-Complexity Rate-Distortion Optimization for HEVC Encoders

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      Authors: Bo Huang;Zhifeng Chen;Kaixiong Su;Jian Chen;Nam Ling;
      Pages: 721 - 735
      Abstract: Typical high efficiency video coding (HEVC) encoders use rate-distortion optimization (RDO) to select the best coding parameters among numerous candidates to achieve high compression efficiency. However, calculating the rate-distortion cost for each coding parameter entails high computational complexity, which limits the real-time application of these encoders. In this study, time-consuming processes, such as reconstruction and entropy coding, are removed during the calculation of the full RD cost to reduce the complexity of the encoder. Instead, RD costs are estimated for transformed coefficients by using the RD cost model, which is made up of a distortion model based on the distribution features of the transformed coefficients, a residual rate model based on the characteristics of the entropy coding module, and a simple and convenient header rate model. In addition to the full RD cost, typical encoders also adopt fast RD cost, which is composed of the sum of absolute transform differences (SATD) and header bit. To further reduce encoding complexity, three simplified SATD (SSATD) methods based on DCT and DST features are proposed to serve as substitutes for SATD in fast RD cost, thus reducing the computational complexity of SATD calculation. Experimental results show that 35.53%, 14.57%, and 14.37% of coding time can be reduced respectively under AI, RA and LDP configurations with negligible RD performance loss when applying the proposed RD cost model and the SSATD methods to HM16.7. Besides, the proposed methods also can reduce 4%–9% of encoding time and exhibits the same RD performance as state-of-the-art methods.
      PubDate: Sept. 2021
      Issue No: Vol. 67, No. 3 (2021)
       
  • User-Priority Based AV1 Coding Tool Selection

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      Authors: Motong Xu;Byeungwoo Jeon;
      Pages: 736 - 745
      Abstract: AV1 is an open-source video coding technique developed by Alliance for Open Media (AOMedia). Many powerful coding tools introduced to AV1 has made its encoding time significantly increased. In this paper, we aim at simplifying the AV1 encoder by facilitating selection of some coding tools depending on users’ specific application preference. We firstly design a coding tool OFF-test to evaluate coding performance of intra, inter, and in-loop filter coding tools in AV1 encoder in order to define a criterion to evaluate the importance of each coding tool by measuring the Bjøntegaard delta bit rate (BDBR) loss and time saving (TS) when each coding tool is turned OFF. Furthermore, the importance of each coding tool is analyzed based on the predefined criterion. Lastly, we suggest two intra coding tool selection methods, three inter coding tool selection methods, and three overall coding tool selection methods to simplify AV1 encoder based on users’ preference of quality-priority or low-complexity-priority. Experimental results show that our proposed low-complexity-priority selection method saves 30.72% of encoding time with only 0.91% loss in BDBR sense, and the quality-priority selection method saves 4.64% of encoding time with 0.02% BDBR loss.
      PubDate: Sept. 2021
      Issue No: Vol. 67, No. 3 (2021)
       
  • A Combined Field-of-View Prediction-Assisted Viewport Adaptive Delivery
           Scheme for 360° Videos

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      Authors: Abid Yaqoob;Gabriel-Miro Muntean;
      Pages: 746 - 760
      Abstract: Recently, 360° or omnidirectional videos have become increasingly popular for both personal and enterprize use-cases. However, 360° video streaming has very high bandwidth and processing requirements. State-of-the-art viewport-based streaming solutions lower these requirements by performing selective streaming based on long-term Field-of-View (FoV) prediction mechanisms. However, sometimes user movement is extremely unpredictable during some parts of the video, and applying these solutions adversely affects the overall quality of experience (QoE). This paper proposes a novel Combined Field-of-View tile-based adaptive streaming solution (CFOV) that improves end-user QoE for 360° video streaming. CFOV performs interactive tile selection based on more accurate dynamical viewing area identification by combining the results of two FoV prediction mechanisms. It also employs an innovative priority-based bitrate adaptation approach that ensures improved bitrate budget distribution between different tiles. We evaluate the proposed solution with a comprehensive set of experiments involving four immersive videos, diverse tiling patterns (i.e., 4×3, 6×4, and 8×6), different segment lengths (i.e., 1s, 2s, and 3s), and 48 empirical head movement traces under different bandwidth settings. The evaluation employs a newly defined QoE metric specifically introduced to assess the streaming performance of 360° videos objectively. The experimental findings show that, compared to alternative approaches, our proposed solution can achieve a higher viewport match and can significantly improve the user QoE for different watching behaviors and content characteristics.
      PubDate: Sept. 2021
      Issue No: Vol. 67, No. 3 (2021)
       
  • On Decomposition and Deployment of Virtualized Media Services

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      Authors: Gourav Prateek Sharma;Didier Colle;Wouter Tavernier;Mario Pickavet;
      Pages: 761 - 775
      Abstract: For decades, broadcasters have heavily relied on specialized hardware appliances for media transport and processing. However, new architectures, where media transport is realized using IP networking and general-purpose compute hardware is used to run Virtual Media Functions (VMFs), are increasingly being adopted in the broadcast industry. To truly exploit the benefits of these architectures, efficient resource allocation algorithms are needed. Hence, we have proposed an algorithm to optimize a media service’s VMF Forwarding Graph (VMF-FG) prior to deployment. To deploy media services, two VMF Placement and Chaining (VMF-PC) algorithms– Next-Fit Placement and Chaining (NFPC) and $k$ -cut Placement and Chaining ( $k$ -cutPC) are proposed. The presented evaluation results compare the performance of the two VMF-PC algorithms along with highlighting the improvement in resource allocation as a result of VMF-FG decomposition.
      PubDate: Sept. 2021
      Issue No: Vol. 67, No. 3 (2021)
       
  • HPA Linearization for Next Generation Broadcasting Systems With Fast
           Convergence-Digital Predistortion

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      Authors: S. S. Krishna Chaitanya Bulusu;Hmaied Shaïek;Daniel Roviras;
      Pages: 776 - 790
      Abstract: The Last decade saw significant growth in the digital terrestrial television (DTT) subscribers. The High peak-to-average power ratio (PAPR) of the transmitted signal is implied by the large fluctuations in its amplitude, which is a serious issue in the contemporary and next generation DTT broadcasting systems. These large fluctuations prevent feeding the high power amplifier (HPA) at an operating point near its non-linear (NL) saturation region, thereby lowering its power efficiency. For a better future, energy-efficient green communications is the need of hour. This paper focuses on digital predistortion (DPD), which is among the widely used techniques for HPA linearization in order to minimize the NL effects. DPD technique requires a feedback signal. This paper proposes a novel adding signal-based digital predistortion, where the output of the HPA is gradually linearized by adding a signal at the input in an iterative manner. By Taylor series approximation, the DPD problem can be posed as a convex one. We prove that a tighter upper bound exists for the convergence factor and instead of directly solving the convex problem, we pick a convergence factor value within its bounds that offers a good trade-off between convergence speed and residual error value. The simulation results show that the proposed technique can quickly linearize the HPA with good convergence.
      PubDate: Sept. 2021
      Issue No: Vol. 67, No. 3 (2021)
       
  • Decoding of Variable Length PLH Codes

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      Authors: Marco Morini;Alessandro Ugolini;Giulio Colavolpe;
      Pages: 791 - 797
      Abstract: In this paper, we address the problem of the decoding of variable length physical layer header (PLH) codes. We take as a case study the DVB-S2X standard, and, after selecting a suitable PLH code with variable codeword length, we propose two alternative noncoherent decoding strategies. The proposed decoding strategies allow to estimate the length of the transmitted PLH field, which is unknown at the receiver, jointly with the decoding of the PLH code. We demonstrate that it is possible to achieve an excellent decoding performance while significantly reducing the overhead due to the transmission of the PLH field with respect to a standard fixed-length PLH.
      PubDate: Sept. 2021
      Issue No: Vol. 67, No. 3 (2021)
       
 
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