Showing items 61 - 80 of 151

Your selections:

Performance scalable motion estimation for video coding : An overview of current status and a promising approach

- Sorwar, Golam, Murshed, Manzur

  • Authors: Sorwar, Golam , Murshed, Manzur
  • Date: 2013
  • Type: Text , Book chapter
  • Relation: Multimedia networking and coding Chapter 3 p. 50-75
  • Full Text: false
  • Reviewed:
  • Description: Motion estimation is one of the major bottlenecks in real-time performance scalable video coding applications due to high computational complexity of exhaustive search. To address this, researchers so far focused on low-complexity motion estimation and rate-distortion optimization in isolation. Proliferation of power-constrained handheld devices with image capturing capability has created demand for much smarter approach where motion estimation is integrated with rate control such that rate-distortion-complexity optimization can be effectively achieved. It is indeed crucial to provide such performance scalability in motion estimation to facilitate complexity management in such devices. This chapter presents an overview of motion estimation. Beginning with an introduction to the importance of motion estimation, it systematically examines various motion estimation techniques and their strengths and weaknesses, focussing primarily on block-based motion search. It then examines the limitation of the existing techniques in accommodating performance scalability, introduces a promising approach, Distance-dependent Thresholding Search (DTS) motion search, to fill in this gap, and concludes with future research directions in the field. The authors suggest that the content of the chapter will make a significant contribution and serve as a reference for multimedia signal processing research at postgraduate level.

Predictive coding of integers with real-valued predictions

- Ali, Mortuza, Murshed, Manzur

  • Authors: Ali, Mortuza , Murshed, Manzur
  • Date: 2013
  • Type: Text , Conference paper
  • Relation: DCC 2013 Data Compression Conference; Snowbird, USA; 20th-22nd March 2013; p. 431-440
  • Relation: http://purl.org/au-research/grants/arc/DP130103670
  • Full Text: false
  • Reviewed:
  • Description: In this paper, we have extended the Rice-Golomb code so that it can operate at fractional precision to efficiently exploit the real-valued predictions. Coding at infinitesimal precision allows the residuals to be modeled with the Lap lace distribution. Unlike the Rice-Golomb code, which maps equally probable opposite-signed residuals to different integers, the proposed coding scheme is symmetric in the sense that, at infinitesimal precision, it assigns code words of equal length to equally probable residual intervals. The symmetry of both the Lap lace distribution and the coding scheme facilitates the analysis of the proposed coding scheme to determine the average code-length and the optimal value of the associated coding parameter.

Preface

- Karim, Mohammad, Kaykobad, Mohammad, Murshed, Manzur

Privacy in participatory sensing systems

- Sabrina, Tishna, Murshed, Manzur

  • Authors: Sabrina, Tishna , Murshed, Manzur
  • Date: 2013
  • Type: Text , Book chapter , Book
  • Relation: Network and Traffic Engineering in Emerging Distributed Computing Applications. Chapter 6. pg 124-143
  • Full Text: false
  • Reviewed:
  • Description: Participatory sensing is a revolutionary new paradigm where ordinary citizens voluntarily sense their environment using readily available sensor devices such as mobile phones and systematically study, and then reflect on and share this information using existing wireless networks. It provides data collection, processing, and dissemination opportunities for socially-responsible applications spanning environmental monitoring, intelligent transportation, and public health, which are often not cost-viable using dedicated sensing infrastructure. The uniqueness of the participatory sensing system lies in its data communication infrastructure which is constituted by the deliberate participation of community people. However, the potential lack of privacy of the participants in such system makes it harder to ensure their voluntary contribution. Thus preserving privacy of the individuals contributing data has introduced a key challenge in this area. On the other hand, data integrity is desired imperatively to make the service trustworthy and user-friendly. Different interesting approaches have been proposed so far to protect privacy that will encourage participation of the owners of data sources in turn.

Technical challenges and design issues in Bangla language processing

- Karim, Mohammad, Kaykobad, Mohammad, Murshed, Manzur

Undecoded coefficients recovery in distributed video coding by exploiting spatio-temporal correlation: a linear programming approach

- Ali, Mortuza, Murshed, Manzur

  • Authors: Ali, Mortuza , Murshed, Manzur
  • Date: 2013
  • Type: Text , Conference proceedings
  • Relation: Proceedings of IEEE International Conference on Digital Image Computing: Techniques and Applications (DICTA 2013), Hobart, November 26-28th, 2013, p 1-7
  • Full Text: false
  • Reviewed:
  • Description: Distributed video coding (DVC) aims at achieving low-complexity encoding in contrast to the existing video coding standards' high complexity encoding. According to the Wyner-Ziv theorem this can be achieved, under certain conditions, by independent encoding of the frames while resorting to joint decoding. However, the performance of a Wyner-Ziv coding scheme significantly depends on its knowledge about the spatio-temporal correlation of the video. Unfortunately, correlation statistics in a video widely varies both along the spatial and temporal directions. Therefore, we argue that in a feedback free transform domain DVC scheme the decoder will fail to recover all the transform coefficients with a nonzero probability. Thus, we suggest to integrate a recovery method with the decoder that aims at recovering the undecoded coefficients by exploiting the spatio-temporal correlation of the video. Besides, we extend and modify a recovery scheme, recently proposed in the context of images, for DVC so that it exploits both spatial and temporal correlations in recovering the undecoded coefficients. The essential idea of this scheme is to formulate the recovery problem as a linear optimization problem which can be solved efficiently using linear programming. Our simulation results demonstrated that the proposed scheme can significantly improve the PSNR and visual quality of the erroneous video frames produced by a DVC decoder.

Verifiable and privacy preserving electronic voting with untrusted machines

- Murshed, Manzur, Sabrina, Tishna, Iqbal, Anindya, Ali, Mortuza

  • Authors: Murshed, Manzur , Sabrina, Tishna , Iqbal, Anindya , Ali, Mortuza
  • Date: 2013
  • Type: Text , Conference proceedings
  • Relation: Proceedings of the 12th IEEE International Conference on Trust, Security and Privacy in Computing and Communications (TrustCom 2013) Melbourne, Vic, 16-18th July, 2013 p. 798-804
  • Full Text: false
  • Reviewed:
  • Description: Designing a trustworthy voting system that uses electronic voting machines (EVMs) for efficiency and accuracy is a challenging task. It is difficult, if not impossible, to ensure the trustworthiness of EVMs that possess computation, storage, and communication capabilities. Thus an electronic voting system that does not assume trusted EVMs is clearly desirable. In this paper, we have proposed a k-anonymized electronic voting scheme that achieves this goal by assuming a hardware-controlled trusted random number generator external to the EVM. The proposed scheme relies on a k-anonymization technique to protect privacy and resort to joint de-anonymization of the votes for counting. Since the joint de-anonymization takes into account all the votes, it is difficult to manipulate an individual vote, even by the EVM, without being detected. Besides the anonymization technique, the proposed scheme relies on standard cryptographic hashing and the concept of floating receipt to provide end-to-end verifiability that prevents coercion or vote trading.

A novel video coding scheme using a scene adaptive non-parametric background model

- Chakraborty, Subrata, Paul, Manoranjan, Murshed, Manzur, Ali, Mortuza

  • Authors: Chakraborty, Subrata , Paul, Manoranjan , Murshed, Manzur , Ali, Mortuza
  • Date: 2014
  • Type: Text , Conference paper
  • Relation: 16th IEEE International Workshop on Multimedia Signal Processing, MMSP 2014 p. 1-6
  • Relation: http://purl.org/au-research/grants/arc/DP130103670
  • Full Text:
  • Reviewed:
  • Description: Video coding techniques utilising background frames, provide better rate distortion performance by exploiting coding efficiency in uncovered background areas compared to the latest video coding standard. Parametric approaches such as the mixture of Gaussian (MoG) based background modeling has been widely used however they require prior knowledge about the test videos for parameter estimation. Recently introduced non-parametric (NP) based background modeling techniques successfully improved video coding performance through a HEVC integrated coding scheme. The inherent nature of the NP technique naturally exhibits superior performance in dynamic background scenarios compared to the MoG based technique without a priori knowledge of video data distribution. Although NP based coding schemes showed promising coding performances, they suffer from a number of key challenges - (a) determination of the optimal subset of training frames for generating a suitable background that can be used as a reference frame during coding, (b) incorporating dynamic changes in the background effectively after the initial background frame is generated, (c) managing frequent scene change leading to performance degradation, and (d) optimizing coding quality ratio between an I-frame and other frames under bit rate constraints. In this study we develop a new scene adaptive coding scheme using the NP based technique, capable of solving the current challenges by incorporating a new continuously updating background generation process. Extensive experimental results are also provided to validate the effectiveness of the new scheme.

An efficient video coding technique using a novel non-parametric background model

- Chakraborty, Subrata, Paul, Manoranjan, Murshed, Manzur, Ali, Mortuza

  • Authors: Chakraborty, Subrata , Paul, Manoranjan , Murshed, Manzur , Ali, Mortuza
  • Date: 2014
  • Type: Text , Conference proceedings
  • Relation: 2014 IEEE International Conference on Multimedia and Expo Workshops, ICMEW 2014; Chengdu; China; 14th-18th July 2014 p. 1-6
  • Full Text:
  • Reviewed:
  • Description: Video coding technique with a background frame, extracted from mixture of Gaussian (MoG) based background modeling, provides better rate distortion performance by exploiting coding efficiency in uncovered background areas compared to the latest video coding standard. However, it suffers from high computation time, low coding efficiency for dynamic videos, and prior knowledge requirement of video content. In this paper, we present a novel adaptive weighted non-parametric (WNP) background modeling technique and successfully embed it into HEVC video coding standard. Being non-parametric (NP), the proposed technique naturally exhibits superior performance in dynamic background scenarios compared to MoG-based technique without a priori knowledge of video data distribution. In addition, the WNP technique significantly reduces noise-related drawbacks of existing NP techniques to provide better quality video coding with much lower computation time as demonstrated through extensive comparative studies against NP, MoG and HEVC techniques.

Distributed database management systems : Architectural design choices for the cloud

- Kamal, Joarder, Murshed, Manzur

  • Authors: Kamal, Joarder , Murshed, Manzur
  • Date: 2014
  • Type: Text , Book chapter
  • Relation: Cloud Computing : Challenges, Limitations and R&D Solutions (Computer Communications and Networks series) Chapter 2 p. 23-50
  • Full Text: false
  • Reviewed:
  • Description: Cloud computing has changed the way we used to exploit software and systems. The two decades’ practice of architecting solutions and services over the Internet has just revolved within the past few years. End users are now relying more on paying for what they use instead of purchasing a full-phase license. System owners are also in rapid hunt for business profits by deploying their services in the Cloud and thus maximising global outreach and minimising overall management costs. However, deploying and scaling Cloud applications regionally and globally are highly challenging. In this context, distributed data management systems in the Cloud promise rapid elasticity and horizontal scalability so that Cloud applications can sustain enormous growth in data volume, velocity, and value. Besides, distributed data replication and rapid partitioning are the two fundamental hammers to nail down these challenges. While replication ensures database read scalability and georeachability, data partitioning favours database write scalability and system-level load balance. System architects and administrators often face difficulties in managing a multi-tenant distributed database system in Cloud scale as the underlying workload characteristics change frequently. In this chapter, the inherent challenges of such phenomena are discussed in detail alongside their historical backgrounds. Finally, potential way outs to overcome such architectural barriers are presented under the light of recent research and development in this area.

Efficient coding of depth map by exploiting temporal correlation

- Shahriyar, Shampa, Murshed, Manzur, Ali, Mortuza, Paul, Manoranjan

  • Authors: Shahriyar, Shampa , Murshed, Manzur , Ali, Mortuza , Paul, Manoranjan
  • Date: 2014
  • Type: Text , Conference proceedings
  • Relation: 2014 International Conference on Digital Image Computing : Techniques and Applications (DICTA); Wollongong, Australia; 25th-27th November 2014
  • Relation: http://purl.org/au-research/grants/arc/DP130103670
  • Full Text: false
  • Description: With the growing demands for 3D and multi-view video content, efficient depth data coding becomes a vital issue in image and video coding area. In this paper, we propose a simple depth coding scheme using multiple prediction modes exploiting temporal correlation of depth map. Current depth coding techniques mostly depend on intra-coding mode that cannot get the advantage of temporal redundancy in the depth maps and higher spatial redundancy in inter-predicted depth residuals. Depth maps are characterized by smooth regions with sharp edges that play an important role in the view synthesis process. As depth maps are more sensitive to coding errors, use of transformation or approximation of edges by explicit edge modelling has impact on view synthesis quality. Moreover, lossy compression of depth map brings additional geometrical distortion to synthetic view. In this paper, we have demonstrated that encoding inter-coded depth block residuals with quantization at pixel domain is more efficient than the intra-coding techniques relying on explicit edge preservation. On standard 3D video sequences, the proposed depth coding has achieved superior image quality of synthesized views against the new 3D-HEVC standard for depth map bit-rate 0.25 bpp or higher.

Efficient HEVC scheme using motion type categorization

- Podder, Pallab, Paul, Manoranjan, Murshed, Manzur

Energy-aware virtual machine consolidation in IaaS cloud computing

- Ferdaus, Md Hasanul, Murshed, Manzur

  • Authors: Ferdaus, Md Hasanul , Murshed, Manzur
  • Date: 2014
  • Type: Text , Book chapter
  • Relation: Cloud Computing : Challenges, Limitations and R&D Solutions (Computer Communications and Networks series) Chapter 8 p. 179-208
  • Full Text: false
  • Reviewed:
  • Description: With immense success and rapid growth within the past few years, cloud computing has been established as the dominant paradigm of IT industry. To meet the increasing demand of computing and storage resources, infrastructure cloud providers are deploying planet-scale data centers across the world, consisting of hundreds of thousands, even millions of servers. These data centers incur very high investment and operating costs for the compute and network devices as well as for the energy consumption. Moreover, because of the huge energy usage, such data centers leave large carbon footprints and thus have adverse effects on the environment. As a result, efficient computing resource utilization and energy consumption reduction are becoming crucial issues to make cloud computing successful. Intelligent workload placement and relocation is one of the primary means to address these issues. This chapter presents an overview of the infrastructure resource management systems and technologies and detailed description of the proposed solution approaches for efficient cloud resource utilization and minimization of power consumption and resource wastages. Different types of server consolidation mechanisms are presented along with the solution approaches proposed by the researchers of both academia and industry. Various aspects of workload reconfiguration mechanisms and existing works on workload relocation techniques are described.

Inherently edge-preserving depth-map coding without explicit edge detection and approximation C3 - Proceedings - IEEE International Conference on Multimedia and Expo

- Shahriyar, Shampa, Murshed, Manzur, Ali, Mortuza, Paul, Manoranjan

  • Authors: Shahriyar, Shampa , Murshed, Manzur , Ali, Mortuza , Paul, Manoranjan
  • Date: 2014
  • Type: Text , Conference proceedings
  • Full Text: false
  • Description: In emerging 3D video coding, depth has significant importance in view synthesis, scene analysis, and 3D object reconstruction. Depth images can be characterized by sharp edges and smooth large regions. Most of the existing depth coding techniques use intra-coding mode and try to preserve edges explicitly with approximated edge modelling. However, edges can be implicitly preserved as long as the transformation is avoided. In this paper, we have demonstrated that inherent edge preserving encoding of inter-coded block residuals, uniformly quantized at pixel domain using motion data from associated texture components, is more efficient than explicitly edge preserving intra-coding techniques. Experimental results show that the proposed technique have achieved superior image quality of synthesized views against the new 3D-HEVC standard. Lossless applications of the proposed technique has achieved on average 66% and 23% bit-rate savings against 3D-HEVC with negligible quantization and perceptually unnoticeable view synthesis, respectively.

On demand-driven movement strategy for moving beacons in sensor localization

- Iqbal, Anindya, Murshed, Manzur

  • Authors: Iqbal, Anindya , Murshed, Manzur
  • Date: 2014
  • Type: Text , Journal article
  • Relation: Journal of Network and Computer Applications Vol. 44, no. (2014), p. 46-62
  • Full Text: false
  • Reviewed:
  • Description: In wireless sensor networks, estimating sensor location demands a large number of neighbor location references due to the unavoidable wireless signal attenuation problem. However, the cost of deployment increases with the increase in beacon location references. This limitation can be overcome using moving beacons exploiting the control over the number, position, and strength of beacon transmissions. In this scenario, the trade-off between localization cost and accuracy, which are directly linked up with anchor movement and transmission pattern, introduces many challenges that have recently attracted research interest. This paper aims to propose a noise-tolerant and cost-effective range-free localization technique using moving beacons that localize randomly deployed sensor nodes within a maximum localization error bound while minimizing the cost of beacon traversal and transmissions. We found that the mean localization error can be kept within 20–35% of the maximum transmission radius by selecting the movement and beacon transmission parameters according to user demand. The proposed schemes are compared with other works and also shown to be robust against positional errors of the moving beacon.

Predicting Hot-Spots in distributed cloud databases using association rule mining

- Kaml, Joarder, Murshed, Manzur, Gaber, Mohamed

  • Authors: Kaml, Joarder , Murshed, Manzur , Gaber, Mohamed
  • Date: 2014
  • Type: Text , Conference paper
  • Relation: IEEE/ACM 7th International Conference Utility and Cloud Computing (UCC), 2014; London; 8-11th December, 2014 p. 800-805
  • Full Text: false
  • Reviewed:
  • Description: Data partitioning is a popular technique to horizontally or vertically split table attributes of a Cloud database cluster to evenly distribute increasing workloads. However, hot-spots can be created due to inappropriate partitioning scheme and static partition management without considering the dynamic workload characteristics. In this paper, an automatic database partition management scheme - APM - is proposed which periodically analyses workload logs to predict the formation of any potential hot-spot using association rule mining. A detailed illustration of the proposed scheme is presented with examples along with a cost model following by experimental observations from running a HBase cluster with YCSB workloads in AWS.

Progressive data stream mining and transaction classification for workload-aware incremental database repartitioning

- Kamal, Joarder, Murshed, Manzur, Gaber, Mohamed

  • Authors: Kamal, Joarder , Murshed, Manzur , Gaber, Mohamed
  • Date: 2014
  • Type: Text , Conference proceedings
  • Relation: IEEE/ACM International Symposium on Big Data Computing, BDC 2014; London, United Kingdom; 8th-11th December 2014; p. 8-15
  • Full Text:
  • Reviewed:
  • Description: Minimising the impact of distributed transactions (DTs) in a shared-nothing distributed database is extremely challenging for transactional workloads. With dynamic workload nature and rapid growth in data volume the underlying database requires incremental repartitioning to maintain acceptable level of DTs and data load balance with minimum physical data migrations. In a workload-aware repartitioning scheme transactional workload is modelled as graph or hyper graph, and subsequently perform k-way min-cut clustering guaranteeing minimum edge cuts can reduce the impact of DTs significantly by mapping the workload clusters into logical database partitions. However, without exploring the inherent workload characteristics, the overall processing and computing times for large-scale workload networks increase in polynomial orders. In this paper, a workload-aware incremental database repartitioning technique is proposed, which effectively exploits proactive transaction classification and workload stream mining techniques. Workload batches are modelled in graph, hyper graph, and compressed hyper graph then repartitioned to produce a fresh tuple-to-partition data migration plan for every incremental cycle. Experimental studies in a simulated TPC-C environment demonstrate that the proposed model can be effectively adopted in managing rapid data growth and dynamic workloads, thus progressively reduce the overall processing time required to operate over the workload networks.

Very low bit rate video coding

- Paul, Manoranjan, Murshed, Manzur

Virtual machine consolidation in cloud data centers using ACO metaheuristic C3 - Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)

- Ferdaus, Md Hasanul, Murshed, Manzur, Calheiros, Rodrigo, Buyya, Rajkumar

  • Authors: Ferdaus, Md Hasanul , Murshed, Manzur , Calheiros, Rodrigo , Buyya, Rajkumar
  • Date: 2014
  • Type: Text , Conference paper
  • Relation: 20th International Conference on Parallel Processing, Euro-Par 2014 Vol. 8632 LNCS, p. 306-317
  • Full Text: false
  • Reviewed:
  • Description: In this paper, we propose the AVVMC VM consolidation scheme that focuses on balanced resource utilization of servers across different computing resources (CPU, memory, and network I/O) with the goal of minimizing power consumption and resource wastage. Since the VM consolidation problem is strictly NP-hard and computationally infeasible for large data centers, we propose adaptation and integration of the Ant Colony Optimization (ACO) metaheuristic with balanced usage of computing resources based on vector algebra. Our simulation results show that AVVMC outperforms existing methods and achieves improvement in both energy consumption and resource wastage reduction.

Workload-aware incremental repartitioning of shared-nothing distributed databases for scalable cloud applications

- Kamal, Joarder, Murshed, Manzur, Buyya, Rajkumar

  • Authors: Kamal, Joarder , Murshed, Manzur , Buyya, Rajkumar
  • Date: 2014
  • Type: Text , Conference paper
  • Relation: 2014 IEEE/ACM 7th International Conference on Utility and Cloud Computing (UCC) p. 213-222
  • Full Text: false
  • Reviewed:
  • Description: Cloud applications often rely on shared-nothing distributed databases that can sustain rapid growth in data volume. Distributed transactions (DTs) that involve data tuples from multiple geo-distributed servers can adversely impact the performance of such databases, especially when the transactions are short-lived in and require immediate response. The k-way min-cut graph clustering algorithm has been found effective to reduce the number of DTs with acceptable level of load balancing. Benefits of such a static partitioning scheme, however, is short-lived in Cloud applications with dynamically varying workload patterns where DT profile changes over time. This paper addresses this emerging challenge by introducing incremental repartitioning. In each repartitioning cycle, DT profile is learnt online and k-way min-cut clustering algorithm is applied on a special sub-graph representing all DTs as well as those non-DTs that have at least one tuple in a DT. The latter ensures that the min-cut algorithm minimally reintroduces new DTs from the non-DTs while maximally transforming existing DTs into non-DTs in the new partitioning. Potential load imbalance risk is mitigated by applying the graph clustering algorithm on the finer logical partitions instead of the servers and relying on random one-to-one cluster-to-partition mapping that naturally balances out loads. Inter-server data-migration due to repartitioning is kept in check with two special mappings favouring the current partition of majority tuples in a cluster -- the many-to-one version minimising data migrations alone and the one-to-one version reducing data migration without affecting load balancing. A distributed data lookup process, inspired by the roaming protocol in mobile networks, is introduced to efficiently handle data migration without affecting scalability. The effectiveness of the proposed framework is evaluated on realistic TPC-C workloads comprehensively using graph, hyper graph, and compressed hyper graph representations used in the literature. Simulation results convincingly support incremental repartitioning against static partitioning.