nils-herrmann/clean_scirepeval huggingface dataset:
Implementation of MPEG system target decoder

The MPEG-2 system standard provides methods for multiplexing a number of elementary MPEG streams into a single system stream. It also defines methods to maintain the synchronization and timing of compressed streams. This is achieved by exact definitions of the times at which data arrive to the decoder, timing of data flow in the decoder and timing of decoding and presentation events. For this purpose, the standard defines a conceptual model for a target decoder, called "system target decoder" (STD), which is used to model the decoding process. System streams generated by the multiplexer should comply with the specifications imposed by the STD model to guarantee the normal operations of real time decoding and presentation process. Therefore, this model is necessary during the construction and verification of system streams. The multiplexer should observe the behavior of STD to ensure that decoder buffers will not overflow or underflow due to encoding or multiplexing issues when receiving the system stream. To achieve this, the scheduler that coordinates the multiplexing order of system packs should consider the monitored information from STD as one of the scheduling control parameters to follow the specifications imposed by STD. This paper describes the theoretical principles, design considerations and architecture of program and transport STDs. The implementations of these target decoders in a software package for verification of MPEG system streams is presented. This implementation uses Microsoft DirectShow. The results of decoding some sample system streams are also presented.
Service-oriented trust and reputation management system for multi-tier cloud

Cloud based applications demand a higher level of security, privacy, and reliability toward a more cost effective solution. One of the challenges for the users of cloud-based services and applications is finding the most trusted provider for the minimum cost. The trusted providers from each customer can have different interpretation, or with different priority of the meaning. Furthermore, a tier-1 cloud service provider that delivers a service can receive the service, partially or fully, from tier-2 cloud service providers. In this paper, we propose a system to evaluate the trust, per delivered service by each provider and per each subject of the trust. Then, we propose an application of our trust system in choosing the best provider by a customer through minimizing the cost and maximizing the service-oriented trust. Our analysis shows the security, efficiency and applicability of our system in a multi-tier cloud environment.
Hybrid view- synthesizing approach for multiview applications

The need for synthesizing virtual views is more pronounced with the advent of multiview displays, as it is not practical to capture all of the possible views when filming multiview content for different multiview display technologies. Unfortunately, during the process of view synthesis, areas, which were occluded by foreground objects in the real views, become visible in the virtual view as holes. Filling these holes with natural looking color and texture information is challenging. We present a new hybrid approach for synthesizing multiview videos, which utilizes an effective hole filling method that preserves the perceptual quality of 3D content. Subjective evaluations confirm that our approach outperforms the current state-of-the-art interpolation-base synthesizing method.
Distance based heuristic for power and rate allocation of video sensor networks

Video sensor networks (VSNs) offer an alternative to several existing surveillance technologies. However, unlike in conventional sensor network, video processing and transmission requires large amount of resources both in signal processing, i.e., encoding, and transmission of the encoded data. For such networks, an optimal encoding power and rate allocation method based on a power-rate-distortion (PRD) analysis has previously been proposed, where the power consumption of video encoding can be controlled by managing some encoding parameters. However, these parameters are currently obtained offline by examining the stored video, an approach which may not be suitable for surveillance applications. In this paper, a distance based heuristic for encoding power and rate allocation of VSNs is proposed. The proposed technique is a practical solution since the video coding parameter is controlled by the node's location in the network. Although the proposed technique offers a sub-optimal solution, in some scenarios it achieves performance up to 94% of the optimal solution in terms of network lifetime.
A scheduling scheme for multiplexing extra streaming data into digital TV programs

In digital TV systems, variable bitrate encoding is usually used to improve the bandwidth usage efficiency. Since the transmission channel has a fixed bandwidth, this leaves some portions of the bandwidth unoccupied. This free space can be used to transmit extra data to enhance the TV content, which can be either discrete, like text, or streaming, like video and audio. We address the problem of adding time-sensitive streaming data to a TV program. The crucial part of this problem is a scheduling algorithm that guarantees the on-time delivery of the incidental data to the decoder. We present a sophisticated time-sensitive scheduling algorithm for off-line multiplexing of TV programs and incidental streaming data. The two important features of our algorithm are: 1) it minimizes the presentation delay for incidental and main streams; 2) it minimizes the required decoder buffer size for incidental data. Comparing the experimental results of our algorithm with existing scheduling methods shows that our algorithm significantly reduces the presentation delay and the decoder buffer size for the incidental streams.
3D medical image coding with optimal channel protection for wireless transmission

We propose a 3D medical image coding method with optimal channel protection for wireless transmission. The proposed method employs the 3D integer wavelet transform and a modified EBCOT with 3D contexts to create a scalable layered bit-stream. Optimal channel protection is attained by assigning protection bits to the different sections of the compressed bit-stream according to their mean energy content. The robustness of the proposed method is evaluated over a Rayleigh-fading channel with a concatenation of a cyclic redundancy check code and a rate-compatible convolutional code. Comparisons are made with the cases of equal channel protection and unequal channel protection. Simulation results show a significant improvement in reconstruction quality of the received 3D images.
An enhanced distributed channel access deficit round-robin (EDRR) access scheme for IEEE 802.11 wireless networks

IEEE 802.11 wireless LAN is the most popular and most widely deployed Wi-Fi technology in the world. With the explosion in use of wireless networks comes the demand for them to support the latest technologies. Task group E of the 802.11 standard is working on a standard that adds quality of service enhancements in the 802.11 MAC layer by using traffic flows and prioritizing traffic according to what type of application it belongs to. There are, however, some weaknesses in the design that is currently being proposed by the 802.11 standards committee. In this paper, we propose enhancements to the IEEE 802.11 draft standard in an attempt to provide improved quality of service for all traffic priorities. Through our simulations we are able to show that we can do so without negatively affecting the performance of any of the wireless stations in the network or the traffic flows that they contain. Our results show that the proposed scheme provides an attractive and effective mechanism for enhancing the IEEE 802.11 standard.
A noise resistant HDTV compression scheme

A fixed-length coding method for image compression is presented. This method compresses the discrete cosine transform (DCT) coefficients of 8/spl times/8 pixel blocks of the picture and attains a compression ratio of 11.11:1. We then develop a compression scheme which combines variable-length coding with our fixed-length coding method. This is shown to improve the compression rate as well as the quality of HDTV pictures when undetected bit errors occur.<<ETX>>
A robust watermarking scheme based on informed coding and informed embedding

A watermarking algorithm that relies on informed coding and informed embedding is presented. This method embeds one bit of the watermark in every image block, but offers higher watermarked image quality as well as higher robustness to image processing operation attacks than other known methods using informed coding and informed embedding. The method is shown to withstand high values of added Gaussian noise, valumetric scaling, low-pass filtering as well as lossy JPEG compression. Each bit (0 or 1) to be embedded is represented by a subset of codewords. For every image block, a vector is extracted. This vector is modified so that its correlation with the codewords related to the bit to be embedded in it has higher probability than those of the codewords representing the other bit even if the image is later modified by image processing operations. The vector modification is also carried so that the change in the image fidelity is minimal.
A Fast Video Motion Estimation Algorithm for the H.264 Standard

Video applications are becoming an essential component for mobile devices. H.264, the latest video-coding standard, shows significant potential in terms of bandwidth savings at the cost of substantially increased complexity compared to former standards. The computing power currently available on mobile devices is not sufficient to allow high quality real-time encoding using H.264. Our algorithm uses on average only 0.41% of the computational complexity of the full search method used by H.264, leading to a significant reduction in computational requirements and enabling real-time applications for mobile devices with the efficiency of H.264
Effect of displayed brightness on 3D video viewing

Displayed brightness and contrast are two of the factors that have impact on the 3D quality of experience. In this paper, we quantitatively investigate the effect of brightness and contrast on the viewers' quality of experience when watching 3D videos on 3D displays requiring active or passive glasses. Our results show that people prefer 3D displays that deliver brighter images. Our study also shows that the preferred range of contrast for viewers is -0.5 to 1.5.
Encoding and communication energy consumption trade-off in H.264/AVC based video sensor network

Video sensor networks (VSN) offer an interesting platform for a distributed and flexible surveillance system. In such a system, video compression and wireless transmission are the major operations on each video node. For a battery-powered wireless video sensor, it is essential to maximize the power efficiency of these two operations. Currently, H.264/AVC is the most widely used ITU-T and ISO/IEC video coding standard. Previous works on determining the trade-off between compression and transmission that minimizes energy consumption consider oversimplified coding configurations, thus not taking full advantage of the flexibility and advanced features of H.264/AVC. Choosing the right configuration and setting parameters that lead to optimal encoding performance is of prime importance for video sensor network (VSN) applications, especially since VSN is constrained in terms of bandwidth and energy resources. This paper studies the relationship between the picture quality, the transmission rate, and the complexity of the encoder to expound the energy consumption trade-off between encoding and transmission in VSN. The results of our study can be used as guidelines in optimizing the overall power consumption of a VSN system as it detailed in the paper.
DVB-MHP iTV to Blu-ray system information transcoding

The demand for interactive TV services is rapidly increasing. Most of the interactive TV systems are based on the DVB-MHP (digital video broadcast-multimedia home platform) format. Given the unprecedented success of DVD technology and its already established installed base, it is definitely in the interest of manufactures and end-users to be able to play back DVB-MHP iTV content using a Blu-ray player. This paper analyzes the system information differences between the DVB-MHP and Blu-ray standards, and proposes efficient transcoding methods for generating Blu-ray compatible streams from DVB-MHP data.
Human Visual System-Based Saliency Detection for High Dynamic Range Content

The human visual system (HVS) attempts to select salient areas to reduce cognitive processing efforts. Computational models of visual attention try to predict the most relevant and important areas of videos or images viewed by the human eye. Such models, in turn, can be applied to areas such as computer graphics, video coding, and quality assessment. Although several models have been proposed, only one of them is applicable to high dynamic range (HDR) image content, and no work has been done for HDR videos. Moreover, the main shortcoming of the existing models is that they cannot simulate the characteristics of HVS under the wide luminous range found in HDR content. This paper addresses these issues by presenting a computational approach to model the bottom-up visual saliency for HDR input by combining spatial and temporal visual features. An analysis of eye movement data affirms the effectiveness of the proposed model. Comparisons employing three well-known quantitative metrics show that the proposed model substantially improves predictions of visual attention for HDR content.
A packet prioritization scheme for 3D-HEVC content transmission over LTE networks

Long Term Evolution (LTE) has been standardized at the 3GPP since 2008 and targets the delivery of high data rate services with strict quality-of-service (QoS) requirements. It is now the fastest ever growing mobile technology and is gradually becoming the mainstream radio access technology used in cellular networks. The latest video coding standard, High Efficiency Video Coding (HEVC), achieves higher compression rate than its predecessor Advanced Video Coding (AVC) and for the same level of quality uses almost 50% less bandwidth. HEVC is the leading video compression technology that will be used to deliver high-definition (HD) and ultra-high-definition (UHD) video content to users. Extensions of HEVC, such as 3D-HEVC, are now being developed and standardized by MPEG to deliver 3D video content. The current issues with LTE include its lack of awareness regarding the type of packets being transmitted, and their importance to the end user. The aim of this paper is to investigate the performance of 3D-HEVC over LTE networks using metrics such as packet loss ratio and average user throughput. We also propose a cross-layer solution in the form of a packet prioritization scheme to help provide better quality-of-experience (QoE) to users and demonstrate its advantages over a baseline scheme that is not QoE-aware.
Energy Efficient Multiple Description Coding for Video Sensor Network

Video transmission over wireless sensor networks (WSN) is a very challenging research field. With sensor nodes operate on limited energy resource, computational power and network bandwidth, energy efficient coding and transmission are of extreme important. As opposed to normal video system, video sensor network (VSN) system needs to provide high quality information only when situation calls for it. However, a certain degree of quality has to be guaranteed, especially for the region of interest (ROI) part. In this paper, a simple technique based on multiple description coding (MDC) to reduce the amount of information transmitted while maintaining a higher quality standard for the ROI part of the frame is proposed. Experimental results show some significant gain in energy conservation as compared to the existing techniques.
A robust method for fitting the (/spl sigma//spl I.oarr/, /spl rho//spl I.oarr/) model to a traffic source

A communication network, which offers a deterministic QoS guarantee to VBR traffic sources, must use a traffic regulation scheme to reserve network resources for each source. The key component of a traffic regulation scheme is the traffic characterization model used to characterize the traffic of each source. The (/spl sigma//spl I.oarr/, /spl rho//spl I.oarr/)model is so far the most popular traffic model used in communication networks. In order to achieve high network utilization, parameters of the traffic model should be selected carefully, such that the model specifies the actual traffic as accurately as possible. We present a novel method for selecting the parameters of a (/spl sigma//spl I.oarr/, /spl rho//spl I.oarr/)model for a VBR traffic source. Our method strives for accuracy, implementation simplicity and execution speed as the design goals. Our approach consists of two parts: 1) constructing the empirical envelope of the source from the traffic, and 2) finding the model parameters from the empirical envelope. We present novel solutions for these two problems. Our method for constructing the empirical envelope is faster and more accurate than the presently existing methods and can be employed in real-time applications. Our method for finding the (/spl sigma//spl I.oarr/, /spl rho//spl I.oarr/)model parameters from the empirical envelope is based on the 'divide and conquer' and sequential programming optimization techniques, and finds a near optimum result. The performance and accuracy of our methods were experimentally compared to other available methods. The results showed that the overall performance, specifically the speed and the accuracy of our methods, are significantly better than the current methods found in the literature.
Effective multi-program broadcasting of prerecorded video using VBR MPEG-2 coding

The tradeoff between picture quality and bandwidth usage is a prominent issue in the world of broadcasting. Since broadcasters are able to transmit multiple streams simultaneously in a channel, they face the challenge of guaranteeing the contracted picture quality required by each of the transmitted video streams while maximizing the number of video streams carried in each channel. We have developed an easy to implement MPEG-2 based multi-program video coding system suitable for digital TV broadcast, video on demand, and high definition TV over broadcast satellite networks with limited bandwidth. Compared to present broadcast systems and for the same level of contracted picture quality, our system greatly increases the number of video streams transmitted in each channel. As a result, either a large number of transponders can be freed to carry real-time broadcasting or the level of picture quality can be significantly increased. By switching from tape storage to video server technology, the need for numerous playback (VTR) systems at the headend is eliminated. In addition, the most of the complete MPEG-2 encoders are replaced by much less complex MPEG-2 transcoders. All this means a much more cost-effective solution for broadcast stations.
An optimized link adaptation scheme for efficient delivery of scalable H.264 Video over IEEE 802.11n

In this paper, we propose a cross-layer optimization scheme for delivery of scalable video over variable bit-rate wireless networks, in particular 802.11 based wireless local area networks (WLAN). For scalable video streaming applications, the conventional solution to reduced throughput due to channel distortions is to reduce the video bitrate by dropping the higher enhancement layers of the scalable video. We show that video quality can be improved, without adding to traffic load, when the WLAN link adaptation scheme uses a temporal fairness criterion along with scalable video distortion estimates to adjust its physical (PHY) layer modulation and coding parameters used for delivering each video layer. We formulate the problem as an optimization problem for assigning different PHY modes to different layers of scalable video under temporal fairness constrains; the solution to this problem provides a set of PHY configuration parameters that achieve the highest possible video quality while meeting the admission control constraints. Performance evaluations demonstrate the effectiveness of our method and the accuracy of the models.
An Efficient MPEG2 to H.264 Half-Pixel Motion Compensation Transcoding

An efficient MPEG2 to H.264 half-pixel motion compensation transcoding method is proposed. The Inter macroblock transcoding is implemented in the transform domain. An algorithm is designed to compensate for the errors which arise because of the different half-pixel interpolation procedures used by MPEG2 and H.264/AVC. The experimental results show that the PSNR values of the transcoded H.264 streams result in significant improvement (average 5.5 dB) after we reduce the half-pixel interpolation errors.
Rendering 3-D High Dynamic Range Images: Subjective Evaluation of Tone-Mapping Methods and Preferred 3-D Image Attributes

High dynamic range (HDR) images provide superior picture quality by allowing a larger range of brightness levels to be captured and reproduced than traditional 8-bit low dynamic range (LDR) images. Even with existing 8-bit displays, picture quality can be significantly improved if content is first captured in HDR format, and then is tone-mapped to convert it from HDR to the LDR format. Tone mapping methods have been extensively studied for 2-D images. This paper addresses the problem of presenting stereoscopic tone-mapped HDR images on 3-D LDR displays and how it is different from the 2-D scenario. We first present a subjective psychophysical experiment that evaluates existing tone-mapping operators on 3-D HDR images. The results show that 3-D content derived using tone-mapping is much preferred to that captured directly with a pair of LDR cameras. Global (spatially invariant) and local (spatially variant) tone-mapping methods have similar 3-D effects. The second part of our study focuses on how the preferred level of brightness and the preferred amount of details differ between 3-D and 2-D images by conducting another set of subjective experiments. Our results show that while people selected slightly brighter images in 3-D viewing compared to 2-D, the difference is not statistically significant. However, compared to 2-D images, the subjects consistently preferred having a greater amount of details when watching 3-D. These results suggest that 3-D content should be prepared differently (sharper and possibly slightly brighter) from the same content intended for 2-D displaying, to achieve optimal appearance in each format. The complete database of the original HDR image pairs and their LDR counterparts are available online.
A high performance fixed-length compression method using the Karhunen-Loeve transform

A compression method is presented which combines the distinct advantage of being fixed length with the visual picture quality of transform-based coding methods. This method compresses the Karhunen-Loeve transform coefficients of 8/spl times/8 pixel blocks of the picture and attains a compression ratio of 15.37:1 for color images. Compared to the absolute moment block truncation coding, the other known fixed length compression method, our method improves the compression ratio by 68% and significantly improves the visual quality of the reconstructed picture.