| 1. |
- Afzal, Hassan, et al.
(författare)
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Full 3D Reconstruction of Non-Rigidly Deforming Objects
- 2018
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Ingår i: ACM Transactions on Multimedia Computing, Communications, and Applications (TOMCCAP). - : Association for Computing Machinery (ACM). - 1551-6857 .- 1551-6865. ; 14:1s
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Tidskriftsartikel (refereegranskat)abstract
- In this article, we discuss enhanced full 360 degrees 3D reconstruction of dynamic scenes containing non-rigidly deforming objects using data acquired from commodity depth or 3D cameras. Several approaches for enhanced and full 3D reconstruction of non-rigid objects have been proposed in the literature. These approaches suffer from several limitations due to requirement of a template, inability to tackle large local deformations and topology changes, inability to tackle highly noisy and low-resolution data, and inability to produce online results. We target online and template-free enhancement of the quality of noisy and low-resolution full 3D reconstructions of dynamic non-rigid objects. For this purpose, we propose a view-independent recursive and dynamic multi-frame 3D super-resolution scheme for noise removal and resolution enhancement of 3D measurements. The proposed scheme tracks the position and motion of each 3D point at every timestep by making use of the current acquisition and the result of the previous iteration. The effects of system blur due to per-point tracking are subsequently tackled by introducing a novel and efficient multi-level 3D bilateral total variation regularization. These characteristics enable the proposed scheme to handle large deformations and topology changes accurately. A thorough evaluation of the proposed scheme on both real and simulated data is carried out. The results show that the proposed scheme improves upon the performance of the state-of-the-art methods and is able to accurately enhance the quality of low-resolution and highly noisy 3D reconstructions while being robust to large local deformations.
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| 2. |
- Carlsson, Niklas, 1977-, et al.
(författare)
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Cross-user Similarities in Viewing Behavior for 360°Video and Caching Implications
- 2023
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Ingår i: ACM Transactions on Multimedia Computing, Communications, and Applications (TOMCCAP). - : ASSOC COMPUTING MACHINERY. - 1551-6857 .- 1551-6865. ; 19:5
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Tidskriftsartikel (refereegranskat)abstract
- The demand and usage of 360°video services are expected to increase. However, despite these services being highly bandwidth intensive, not much is known about the potential value that basic bandwidth saving techniques such as server or edge-network on-demand caching (e.g., in a CDN) could have when used for delivery of such services. This problem is both important and complicated as client-side solutions have been developed that split the full 360°view into multiple tiles, and adapt the quality of the downloaded tiles based on the user’s expected viewing direction and bandwidth conditions. This paper presents new trace-based analysis methods that incorporate users’ viewports (the area of the full 360°view the user actually sees), a first characterization of the cross-user similarities of the users’ viewports, and a trace-based analysis of the potential bandwidth savings that caching-based techniques may offer under different conditions. Our analysis takes into account differences in the time granularity over which viewport overlaps can be beneficial for resource saving techniques, compares and contrasts differences between video categories, and accounts for uncertainties in the network conditions and the prediction of the future viewing direction when prefetching. The results provide substantial insight into the conditions under which overlap can be considerable and caching effective, and inform the design of new caching system policies tailored for 360°video.
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| 3. |
- Carlsson, Niklas, et al.
(författare)
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Server Selection in Large-scale Video-on-Demand Systems
- 2010
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Ingår i: ACM Transactions on Multimedia Computing, Communications, and Applications (TOMCCAP). - : ACM. - 1551-6857 .- 1551-6865. ; 6:1, s. 1:1-1:26
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Tidskriftsartikel (refereegranskat)abstract
- Video on demand, particularly with user-generated content, is emerging as one of the most bandwidth-intensive applications on the Internet. Owing to content control and other issues, some video-on-demand systems attempt to prevent downloading and peer-to-peer content delivery. Instead, such systems rely on server replication, such as via third-party content distribution networks, to support video streaming (or pseudostreaming) to their clients. A major issue with such systems is the cost of the required server resources. By synchronizing the video streams for clients that make closely spaced requests for the same video from the same server, server costs (such as for retrieval of the video data from disk) can be amortized over multiple requests. A fundamental trade-off then arises, however, with respect to server selection. Network delivery cost is minimized by selecting the nearest server, while server cost is minimized by directing closely spaced requests for the same video to a common server. This article compares classes of server selection policies within the context of a simple system model. We conclude that: (i) server selection using dynamic system state information (rather than only proximities and average loads) can yield large improvements in performance, (ii) deferring server selection for a request as late as possible (i.e., until just before streaming is to begin) can yield additional large improvements, and (iii) within the class of policies using dynamic state information and deferred selection, policies using only “local” (rather than global) request information are able to achieve most of the potential performance gains.
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| 4. |
- Demisse, Girum G., et al.
(författare)
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Deformation-Based 3D Facial Expression Representation
- 2018
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Ingår i: ACM Transactions on Multimedia Computing, Communications, and Applications (TOMCCAP). - : Association for Computing Machinery (ACM). - 1551-6857 .- 1551-6865. ; 14:1s, s. 17-1
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Tidskriftsartikel (refereegranskat)abstract
- We propose a deformation-based representation for analyzing expressions fromthree-dimensional (3D) faces. A point cloud of a 3D face is decomposed into an ordered deformable set of curves that start from a fixed point. Subsequently, a mapping function is defined to identify the set of curves with an element of a high-dimensional matrix Lie group, specifically the direct product of SE(3). Representing 3D faces as an element of a high-dimensional Lie group has two main advantages. First, using the group structure, facial expressions can be decoupled from a neutral face. Second, an underlying non-linear facial expression manifold can be captured with the Lie group and mapped to a linear space, Lie algebra of the group. This opens up the possibility of classifying facial expressions with linear models without compromising the underlying manifold. Alternatively, linear combinations of linearised facial expressions can be mapped back from the Lie algebra to the Lie group. The approach is tested on the Binghamton University 3D Facial Expression (BU-3DFE) and the Bosphorus datasets. The results show that the proposed approach performed comparably, on the BU-3DFE dataset, without using features or extensive landmark points.
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| 5. |
- Hu, Xiping, et al.
(författare)
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SAfeDJ : A crowd-cloud codesign approach to situation-aware music delivery for drivers
- 2015
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Ingår i: ACM Transactions on Multimedia Computing, Communications, and Applications (TOMCCAP). - : Association for Computing Machinery (ACM). - 1551-6857 .- 1551-6865. ; 12:1s, s. 21:1-24
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Tidskriftsartikel (refereegranskat)abstract
- Driving is an integral part of our everyday lives, but it is also a time when people are uniquely vulnerable. Previous research has demonstrated that not only does listening to suitable music while driving not impair driving performance, but it could lead to an improved mood and a more relaxed body state, which could improve driving performance and promote safe driving significantly. In this article, we propose SAfeDJ, a smartphone-based situation-aware music recommendation system, which is designed to turn driving into a safe and enjoyable experience. SAfeDJ aims at helping drivers to diminish fatigue and negative emotion. Its design is based on novel interactive methods, which enable in-car smartphones to orchestrate multiple sources of sensing data and the drivers' social context, in collaboration with cloud computing to form a seamless crowdsensing solution. This solution enables different smartphones to collaboratively recommend preferable music to drivers according to each driver's specific situations in an automated and intelligent manner. Practical experiments of SAfeDJ have proved its effectiveness in music-mood analysis, and mood-fatigue detections of drivers with reasonable computation and communication overheads on smartphones. Also, our user studies have demonstrated that SAfeDJ helps to decrease fatigue degree and negative mood degree of drivers by 49.09% and 36.35%, respectively, compared to traditional smartphone-based music player under similar driving situations.
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| 6. |
- Lu, Zhihan, et al.
(författare)
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Multimodal Hand and Foot Gesture Interaction for Handheld Devices
- 2014
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Ingår i: ACM Transactions on Multimedia Computing, Communications, and Applications (TOMCCAP). - : Association for Computing Machinery (ACM). - 1551-6857 .- 1551-6865. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- We present a hand-and-foot-based multimodal interaction approach for handheld devices. Our method combines input modalities (i.e., hand and foot) and provides a coordinated output to both modalities along with audio and video. Human foot gesture is detected and tracked using contour-based template detection (CTD) and Tracking-Learning-Detection (TLD) algorithm. 3D foot pose is estimated from passive homography matrix of the camera. 3D stereoscopic and vibrotactile are used to enhance the immersive feeling. We developed a multimodal football game based on the multimodal approach as a proof-of-concept. We confirm our systems user satisfaction through a user study.
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| 7. |
- Lv, Zhihan, Dr. 1984-, et al.
(författare)
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Deep Learning-based Smart Predictive Evaluation for Interactive Multimedia-enabled Smart Healthcare
- 2022
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Ingår i: ACM Transactions on Multimedia Computing, Communications, and Applications (TOMCCAP). - : Association for Computing Machinery (ACM). - 1551-6857 .- 1551-6865. ; 18:1
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Tidskriftsartikel (refereegranskat)abstract
- Two-dimensional(1) arrays of bi-component structures made of cobalt and permalloy elliptical dots with thickness of 25 nm, length 1 mm and width of 225 nm, have been prepared by a self-aligned shadow deposition technique. Brillouin light scattering has been exploited to study the frequency dependence of thermally excited magnetic eigenmodes on the intensity of the external magnetic field, applied along the easy axis of the elements. This study aims to enhance the security for people's health, improve the medical level further, and increase the confidentiality of people's privacy information. Under the trend of wide application of deep learning algorithms, the convolutional neural network (CNN) is modified to build an interactive smart healthcare prediction and evaluation model (SHPE model) based on the deep learning model. The model is optimized and standardized for data processing. Then, the constructed model is simulated to analyze its performance. The results show that accuracy of the constructed system reaches 82.4%, which is at least 2.4% higher than other advanced CNN algorithms and 3.3% higher than other classical machine algorithms. It is proved based on comparison that the accuracy, precision, recall, and F1 of the constructed model are the highest. Further analysis on error shows that the constructed model shows the smallest error of 23.34 pixels. Therefore, it is proved that the built SHPE model shows higher prediction accuracy and smaller error while ensuring the safety performance, which provides an experimental reference for the prediction and evaluation of smart healthcare treatment in the later stage.
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| 8. |
- Lv, Zhihan, Dr. 1984-, et al.
(författare)
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Smart City Construction and Management by Digital Twins and BIM Big Data in COVID-19 Scenario
- 2022
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Ingår i: ACM Transactions on Multimedia Computing, Communications, and Applications (TOMCCAP). - : Association for Computing Machinery (ACM). - 1551-6857 .- 1551-6865. ; 18:2
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Tidskriftsartikel (refereegranskat)abstract
- With the rapid development of information technology and the spread of Corona Virus Disease 2019 (COVID-19), the government and urban managers are looking for ways to use technology to make the city smarter and safer. Intelligent transportation can play a very important role in the joint prevention. This work expects to explore the building information modeling (BIM) big data (BD) processing method of digital twins (DTs) of Smart City, thus speeding up the construction of Smart City and improve the accuracy of data processing. During construction, DTs build the same digital copy of the smart city. On this basis, BIM designs the building's keel and structure, optimizing various resources and configurations of the building. Regarding the fast data growth in smart cities, a complex data fusion and efficient learning algorithm, namely Multi-Graphics Processing Unit (GPU), is proposed to process the multi-dimensional and complex BD based on the compositive rough set model. The Bayesian network solves the multi-label classification. Each label is regarded as a Bayesian network node. Then, the structural learning approach is adopted to learn the label Bayesian network's structure from data. On the P53-old and the P53-new datasets, the running time of Multi-GPU decreases as the number of GPUs increases, approaching the ideal linear speedup ratio. With the continuous increase of K value, the deterministic information input into the tag BN will be reduced, thus reducing the classification accuracy. When K = 3, MLBN can provide the best data analysis performance. On genbase dataset, the accuracy of MLBN is 0.982 +/- 0.013. Through experiments, the BIM BD processing algorithm based on Bayesian Network Structural Learning (BNSL) helps decision-makers use complex data in smart cities efficiently.
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| 9. |
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| 10. |
- Nilsson, Tommy, et al.
(författare)
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Applying Seamful Design in Location-Based Mobile Museum Applications
- 2016
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Ingår i: ACM Transactions on Multimedia Computing, Communications, and Applications (TOMCCAP). - : Association for Computing Machinery (ACM). - 1551-6857 .- 1551-6865. ; 12:4
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Tidskriftsartikel (refereegranskat)abstract
- The application of mobile computing is currently altering patterns of our behavior to a greater degree than perhaps any other invention. In combination with the introduction of power-efficient wireless communication technologies, such as Bluetooth Low Energy (BLE), designers are today increasingly empowered to shape the way we interact with our physical surroundings and thus build entirely new experiences. However, our evaluations of BLE and its abilities to facilitate mobile location-based experiences in public environments revealed a number of potential problems. Most notably, the position and orientation of the user in combination with various environmental factors, such as crowds of people traversing the space, were found to cause major fluctuations of the received BLE signal strength. These issues are rendering a seamless functioning of any location-based application practically impossible. Instead of achieving seamlessness by eliminating these technical issues, we thus choose to advocate the use of a seamful approach, that is, to reveal and exploit these problems and turn them into a part of the actual experience. In order to demonstrate the viability of this approach, we designed, implemented, and evaluated the Ghost Detector-an educational location-based museum game for children. By presenting a qualitative evaluation of this game and by motivating our design decisions, this article provides insight into some of the challenges and possible solutions connected to the process of developing location-based BLE-enabled experiences for public cultural spaces.
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| 11. |
- Nyström, Marcus, et al.
(författare)
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Effect of Compressed Offline Foveated Video on Viewing Behavior and Subjective Quality
- 2010
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Ingår i: ACM Transactions on Multimedia Computing, Communications, and Applications. - : Association for Computing Machinery (ACM). - 1551-6857 .- 1551-6865. ; 6:1, s. 1-14
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Tidskriftsartikel (refereegranskat)abstract
- Offline foveation is a technique to improve the compression efficiency of digitized video. The general idea behind offline foveation is to blur video regions where no or a small number of previewers look without decreasing the subjective quality for later viewers. It relies on the fact that peripheral vision is reduced compared to central vision, and the observation that during free-viewing humans' gaze positions generally coincide when watching video. In this article, we conduct two experiments to assess how offline foveation affects viewing behavior and subjective quality. In the first experiment, 15 subjects free-viewed six video clips before and after offline foveation whereas in the second experiment we had 17 subjects assessing the quality of these videos after one, two, and three consecutive viewings. Eye movements were measured during the experiments. Results showed that, although offline foveation prior to encoding with H. 264 yielded data reductions up to 52% (20% average) on the tested videos, it had little or no effect on where people looked, their intersubject dispersion, fixation duration, saccade amplitude, or the experienced quality during first-time viewing. However, seeing the videos more than once increased the intersubject dispersion and decreased the subjective quality. In view of these results, we discuss the usage of offline foveated video in practical applications.
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| 12. |
- Riegler, M, et al.
(författare)
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From Annotation to Computer-Aided Diagnosis: Detailed Evaluation of a Medical Multimedia System
- 2017
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Ingår i: ACM TRANSACTIONS ON MULTIMEDIA COMPUTING COMMUNICATIONS AND APPLICATIONS. - : Association for Computing Machinery (ACM). - 1551-6857 .- 1551-6865. ; 13:3
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Holistic medical multimedia systems covering end-to-end functionality from data collection to aided diagnosis are highly needed, but rare. In many hospitals, the potential value of multimedia data collected through routine examinations is not recognized. Moreover, the availability of the data is limited, as the health care personnel may not have direct access to stored data. However, medical specialists interact with multimedia content daily through their everyday work and have an increasing interest in finding ways to use it to facilitate their work processes. In this article, we present a novel, holistic multimedia system aiming to tackle automatic analysis of video from gastrointestinal (GI) endoscopy. The proposed system comprises the whole pipeline, including data collection, processing, analysis, and visualization. It combines filters using machine learning, image recognition, and extraction of global and local image features. The novelty is primarily in this holistic approach and its real-time performance, where we automate a complete algorithmic GI screening process. We built the system in a modular way to make it easily extendable to analyze various abnormalities, and we made it efficient in order to run in real time. The conducted experimental evaluation proves that the detection and localization accuracy are comparable or even better than existing systems, but it is by far leading in terms of real-time performance and efficient resource consumption.
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| 13. |
- Roberto, Pierdicca, et al.
(författare)
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Design, Large-Scale Usage Testing, and Important Metrics for Augmented Reality Gaming Applications
- 2019
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Ingår i: ACM Transactions on Multimedia Computing, Communications, and Applications (TOMCCAP). - : ASSOC COMPUTING MACHINERY. - 1551-6857 .- 1551-6865. ; 15:2
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Tidskriftsartikel (refereegranskat)abstract
- Augmented Reality (AR) offers the possibility to enrich the real world with digital mediated content, increasing in this way the quality of many everyday experiences. While in some research areas such as cultural heritage, tourism, or medicine there is a strong technological investment, AR for game purposes struggles to become a widespread commercial application. In this article, a novel framework for AR kid games is proposed, already developed by the authors for other AR applications such as Cultural Heritage and Arts. In particular, the framework includes different layers such as the development of a series of AR kid puzzle games in an intermediate structure which can be used as a standard for different applications development, the development of a smart configuration tool, together with general guidelines and long-life usage tests and metrics. The proposed application is designed for augmenting the puzzle experience, but can be easily extended to other AR gaming applications. Once the user has assembled the real puzzle, AR functionality within the mobile application can be unlocked, bringing to life puzzle characters, creating a seamless game that merges AR interactions with the puzzle reality. The main goals and benefits of this framework can be seen in the development of a novel set of AR tests and metrics in the pre-release phase (in order to help the commercial launch and developers), and in the release phase by introducing the measures for long-life app optimization, usage tests and hint on final users together with a measure to design policy, providing a method for automatic testing of quality and popularity improvements. Moreover, smart configuration tools, as part of the general framework, enabling multi-app and eventually also multi-user development, have been proposed, facilitating the serialization of the applications. Results were obtained from a large-scale user test with about 4 million users on a set of eight gaming applications, providing the scientific community a workflow for implicit quantitative analysis in AR gaming. Different data analytics developed on the data collected by the framework prove that the proposed approach is affordable and reliable for long-life testing and optimization.
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| 14. |
- Ursu, Marian F, et al.
(författare)
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Interactive TV Narratives : Opportunities, Progress and Challenges
- 2008
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Ingår i: ACM Transactions on Multimedia Computing, Communications, and Applications (TOMCCAP). - : Transactions on Multimedia Computing, Communications, and Applications (TOMCAAP). - 1551-6857 .- 1551-6865. ; 4:4
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Tidskriftsartikel (refereegranskat)abstract
- This paper is motivated by the question whether television should do more than simply offer interactive services alongside (and separately from) traditional linear programmes, in the context of its dominance being seriously challenged and threatened by interactive forms of screen media entertainment. It suggests: yes. Interactive narrativity, i.e. the ability to interact with (and influence) stories whilst they are being told, represents one clear development-path for interactive television. The capabilities of computing technology are ripe for exploring this new form of storytelling, from creation to commercial distribution. The paper starts with looking at the relationship between narrativity and interactivity in the current context of screen media, and identifies clear signs of interest from certain European public broadcasters in interactive TV narratives. It then presents in detail four recent experimental interactive TV productions in the genres of drama, news, and documentary, developed in collaboration with public broadcasters, which illustrate the potential and richness of this new form of storytelling, but also highlight new technological capabilities necessary for such productions. A number of essential technological requirements are then discussed in more detail in the final part. The paper suggests that the ShapeShifting Media Technology, employed in the implementation of the four productions, has made significant advances both at the technological and the creative ends in supporting the development of interactive TV narrativity, but, however, that further developments are required before being able to answer questions such as “would end users want such a form of screen media entertainment?” and “would it be effective for both end-users and producers?”
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| 15. |
- Wang, Jinxia, et al.
(författare)
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DNA Computing-Based Multi-Source Data Storage Model in Digital Twins
- 2023
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Ingår i: ACM Transactions on Multimedia Computing, Communications, and Applications (TOMCCAP). - : Association for Computing Machinery (ACM). - 1551-6857 .- 1551-6865. ; 19:3, s. 1-16
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Tidskriftsartikel (refereegranskat)abstract
- The work aims to study the application of Deoxyribonucleic Acid (DNA) multi-source data storage in Digital Twins (DT). Through the investigation of the research status of DT and DNA computing, the work puts forward the concept of DNA multi-source data storage for DT. Raptor code is improved from the design direction of degree distribution function, and six degree function distribution schemes are proposed in turn in the process of describing the research method. Additionally, a quaternary dynamic Huffman coding method is applied in DNA data storage, combined with the improved concatenated code as the error correction code. Considering the content of cytosine deoxynucleotide (C) and guanine deoxynucleotide Guanine (G) and the distribution of homopolymer in DNA storage, the work proposes and verifies an improved concatenated code algorithm Deoxyribonucleic Acid-Improved Concatenated code (DNA-ICC). The results show that while the Signal-to-Noise Ratio (SNR) increases, the Bit Error Rate (BER) decreases gradually and the trend is similar. But the anti-interference ability of the degree distribution function optimized by the probability transfer method is better. The BER of DNA-ICC scheme decreases with the decrease of error probability, which is stronger than other error correction codes. Compared with the original concatenated code, it saves at least 1.65 s, and has a good control effect on homopolymer. When the size of homopolymer exceeds 4 nt, the probability of homopolymer is only 0.44%. The proposed Quaternary dynamic Huffman code and concatenated error correction code have excellent performance.
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| 16. |
- Norström, Christer, et al.
(författare)
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Special section on factory communication systems
- 2005
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Ingår i: IEEE Transactions on Industrial Informatics. - 1551-3203 .- 1941-0050. ; 1:3, s. 149-150
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 17. |
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