When handover events occur during the transmission of multimedia traffic, efficient handover control procedures and radio resource allocation are necessary to maintain the same QoS of transmitted multimedia traffic because the QoS may be degraded by additional delay and information loss. In this paper we propose a new handover control method for the next generation mobile multimedia networks, in which the handover setup process is done in advance of a handover request by predicting the handover cell from mobile terminal's current position. The handover procedures for real-time sessions are performed based on the handover cell information and the resource reservation condition. The radio resources in the estimated adjacent cells should be reserved and allocated to guarantee the continuity of the real-time sessions. We conduct a simulation model that is focused on the handover failure rate and packet loss rate. The simulation results show that our proposed method provides better performance than the previous methods.

This letter proposes a busy-tone based scheme for reliable and efficient broadcasting in mobile ad hoc networks. Control packets such as RTS, CTS and ACK are ignored in the broadcast scheme, and two busy tones are used, one for channel reservation and the other for negative acknowledgement. Unlike traditional schemes for reliable broadcasting, the proposed scheme is highly efficient as it achieves both collision avoidance and fast packet loss recovery. Simulation results are presented which show the effectiveness of the proposed scheme.

A critical problem after a natural/manmade disaster is to provide immediate post-disaster communication links between the disaster victims and some overlay networks. This paper proposes a novel scheme that uses the surviving Mobile handSets (MS) as sensing nodes to form an auto-configured Hierarchical Cognitive Radio Network (H-CRN). The implementation of this H-CRN is explained through detailed problem scenario statement and step-by-step implementation of automatic identification of emergency situation by the MS nodes. An overview of the cross-layer framework used by the MS nodes is also presented. This novel scheme is tested through some hypothesis along with probability calculations for successful identification of emergency situation, formation of ad hoc group and Emergency Beacon Message (EBM) transmission.

For the acquisition of visual information, the nonuniform sampling process by photoreceptors on the retina occurs at the earliest stage of visual processing. From objects of interest, the human eye receives high visual resolution through nonuniform distribution of photoreceptors. Therefore, this paper proposes auto exposure and focus algorithms for the real-time video camera system based on the visual characteristic of the human eye. For given moving objects, the visual weight is modeled for quantifying the visual importance and the associated auto exposure and focus parameters are derived by applying the weight to the traditional numerical expression, i.e., the DoM (Difference of Median) and Tenengrad methods for auto focus.

Background modeling is one of the most challenging and time consuming tasks in motion detection from video sequence. This paper presents a background independent moving object segmentation algorithm utilizing the spatio-temporal information of the last three frames. Existing three-frame based methods face challenges due to the insignificant gradient information in the overlapping region of difference images and edge localization errors. These methods extract scattered moving edges and experience poor detection rate especially when objects with slow movement exist in the scene. Moreover, they are not much suitable for moving object segmentation and tracking. The proposed method solves these problems by representing edges as segments and applying a novel segment based flexible edge matching algorithm which makes use of gradient accumulation through distance transformation. Due to working with three most recent frames, the proposed method can adapt to changes in the environment. Segment based representation facilitates local geometric transformation and thus it can make proper use of flexible matching to provide an effective solution for tracking. To segment the moving object region from the detected moving edges, we introduce a watershed based algorithm followed by an iterative background removal procedure. Watershed based segmentation algorithm helps to extract moving object with more accurate boundary which eventually achieves higher coding efficiency in content based applications and ensures a good visual quality even in the limited bit rate multimedia communication.

This letter introduces a cost-effective chrominance compensation scheme. The proposed method is applied to both 'INTER 1616' and 'SKIP' modes in only anchor P-pictures. By testing using JVT common test condition, simulation results show that proposed method can obtain average BD-PSNR gains for U and V as 0.14 dB and 0.13 dB, respectively while maintaining almost the same BD-PSNR's for Y. For the range of low bit-rate, it is observed that average BD-PSNR gains for Y, U and V are 0.14 dB, 0.49 dB and 0.53 dB, respectively. Necessary computational complexity is very marginal because the number of anchor P-pictures is very small in comparison with whole coded video sequences. However it can be found that the proposed method can significantly improve the coding efficiencies of color components.

Code construction for digital fingerprinting, which is a copyright protection technique for multimedia, is considered. Digital fingerprinting should deter collusion attacks, where several fingerprinted copies of the same content are mixed to disturb their fingerprints. In this paper, we consider the averaging attack, which is known to be effective for multimedia fingerprinting with the spread spectrum technique. We propose new methods for constructing fingerprinting codes to increase the coding rate of conventional fingerprinting codes, while they guarantee to identify the same number of colluders. Due to the new fingerprinting codes, the system can deal with a larger number of users to supply digital contents.

An area-efficient dynamically reconfigurable architecture is proposed, which is dedicated to media processing. To implement a compact but high performance device, which can be used in consumer applications, the reconfigurable architecture distinctively performs 8-bit operations required for media processing whereas fine-grained operations are executed with the cooperation of a host processor. A heterogeneous reconfigurable array is composed of four types of cells, for which configuration data size is reduced by focusing application domain on media processing. Implementation results show that a multi-standard video decoding can be achieved by the proposed reconfigurable architecture with 1.11.4 mm2 in a 90 nm CMOS technology.

In real-time data-dominated communication and multimedia processing applications, a multi-layer memory hierarchy is typically used to enhance the system performance and also to reduce the energy consumption. Savings of dynamic energy can be obtained by accessing frequently used data from smaller on-chip memories rather than from large background memories. This paper focuses on the reduction of the dynamic energy consumption in the memory subsystem of multidimensional signal processing systems, starting from the high-level algorithmic specification of the application. The paper presents a formal model which identifies those parts of arrays more intensely accessed, taking also into account the relative lifetimes of the signals. Tested on a two-layer memory hierarchy, this model led to savings of dynamic energy from 40% to over 70% relative to the energy used in the case of flat memory designs.

This article presents a new design concept of a glucose oxidase (GOD) electrode as an anode for a biofuel cell based on plasma-polymerized thin film (PPF) of dimethylaminomethylferrocene (DMAMF), which plays a role as an electron transfer mediator between the active site of the enzyme and anodic electrode. The configuration of the anode is a multilayer mixture of DMAMF-PPF and GOD, in which a nano-thin DMAMF-PPF containing a redox mediator was plasma-deposited directly onto a GOD-physisorbed electrode. The optimized biofuel cell with bioanode, in a 20 mM phosphate buffer solution of pH 7.4 containing 10 mM glucose, exhibited a maximum power density of 2.7 µW/cm2 at 20. The film deposition was performed using microfabrication-compatible organic plasma, which therefore suggests this fabrication process has significant potential for enabling high throughput production of micro biofuel cells.

This paper performs application-level QoS and user-level QoS assessment of audio-video streaming in cross-layer designed wireless ad hoc networks. In order to achieve high QoS at the user-level, we employ link quality-based routing in the network layer and media synchronization control in the application layer. We adopt three link quality-based routing protocols: OLSR-SS (Signal Strength), AODV-SS, and LQHR (Link Quality-Based Hybrid Routing). OLSR-SS is a proactive routing protocol, while AODV-SS is a reactive one. LQHR is a hybrid protocol, which is a combination of proactive and reactive routing protocols. For application-level QoS assessment, we performed computer simulation with ns-2 where an IEEE 802.11b mesh topology network with 24 nodes was assumed. We also assessed user-level QoS by a subjective experiment with 30 assessors. From the assessment results, we find AODV-SS the best for networks with long inter-node distances, while LQHR outperforms AODV-SS for short inter-node distances. In addition, we also examine characteristics of the three schemes with respect to the application-level QoS in random topology networks.

Selecting transparently a proper network connection for voice communication will be a fundamental requirement in future multi-mode heterogeneous wireless network. This paper presented a smart session selection (S3) scheme to meet this requirement. Instead of selecting a best access network as in conventional Always Best Connected (ABC) paradigm, S3 enables users to select a best network connection, which consists of source and destination access network pair, to satisfy quality constraint and users' preference. To support S3, we develop a user profile to specify network connection priority. Meanwhile IP multimedia subsystem (IMS) is extended to make smart decision for users. Finally, Analytic Hierarchy Process (AHP) is used to recommend a network connection with assistance of user profile and IMS signaling. An example is illustrated to show that AHP can successfully select a good network connection that fulfills the requirement of users.

To meet the bandwidth requirements of multimedia services, multipath transmission is a promising solution. In this paper, we consider multi-access networks, where WiMAX and WiFi links are set up at the same time. Multipath transmission suffers from the intrinsic problem of out-of-order packet delivery. This has an adverse impact on TCP and even UDP-based delay sensitive applications. However, multimedia streaming services allow some tolerance to transmission delay. Motivated by this observation, we investigate how to split multimedia flows over heterogeneous links. Wireless link capacity varies widely over time due to dynamic radio conditions. The capacity variations should be promptly reflected in traffic splitting in order to accomplish an equal load-balance. A practical prototype system has been implemented. We have performed extensive measurements from a prototype system. Through practical experimental results, we could verify two major research goals. One is that multimedia splitting can improve the overall network performance (e.g., the permitted multimedia sessions or the aggregated bandwidth) while still keeping an acceptable media quality. The other is an adaptation capability to varying link quality. It has been widely investigated under various radio conditions and different monitoring intervals. It is shown that the adaptive technique is effective under dynamic radio environments.

In this letter, we propose a video traffic model based on a class of stochastic processes, which we call truncated GeoY/G/∞ input processes. Group of picture (GOP) size traces are modeled by truncated GeoY/G/∞ input process with gamma-distributed batch sizes Y and Weibull-like autocorrelation function. With full-length MPEG-4 video traces in QCIF, we run simulations to show that our proposed model estimates packet loss ratios at various traffic loads more accurately than existing modeling methods.

This paper proposes the Multimedia Pre-allocation WDMA (MP-WDMA) media access control (MAC) protocol to provide an efficient packet transfer service for metro-wavelength division multiple access (WDMA) networks. MP-WDMA considers three traffic types: constant bit rate (CBR), variable bit rate 1 (VBR1), and VBR2 traffic for a multimedia service as categorized in Multimedia WDMA (M-WDMA) MAC protocol. MP-WDMA is based on pre-allocation WDMA (P-WDMA), but the three traffic types are simultaneously allocated at one time slot, and one of them is selected through low bandwidth control signaling. Namely, a station assigns appropriate priority to input traffic, based on proposed traffic priority rules in MP-WDMA in order to determine the type of traffic. Accordingly, MP-WDMA can reduce station complexity as well as the possibility of idle time slot occurrences, compared with M-WDMA. Additionally, we analytically investigate the channel utilization and channel access delay of MP-WDMA and compare them with those of M-WDMA to find a proper MAC protocol for the networks. As a result, MP-WDMA supports maximally 30% higher channel utilization than M-WDMA regardless of channel and traffic conditions. Furthermore, MP-WDMA reduces the channel access delay of the delay-sensitive VBR2 traffic at the cost of increasing the channel access delay of the delay-insensitive VBR1 traffic. In this regard, MP-WDMA is suitable for the networks in terms of station complexity, channel utilization, and the channel access delay for VBR2 traffic.

A lot of emerging applications like advanced telemedicine and surveillance systems, demand sensors to deliver multimedia content with precise level of QoS enhancement. Minimizing energy in sensor networks has been a much explored research area but guaranteeing QoS over sensor networks still remains an open issue. In this letter we propose a cross-layer approach combining Network and MAC layers, for QoS enhancement in wireless multimedia sensor networks. In the network layer a statistical estimate of sensory QoS parameters is performed and a near-optimal genetic algorithmic solution is proposed to solve the NP-complete QoS-routing problem. On the other hand the objective of the proposed MAC algorithm is to perform the QoS-based packet classification and automatic adaptation of the contention window. Simulation results demonstrate that the proposed protocol is capable of providing lower delay and better throughput, at the cost of reasonable energy consumption, in comparison with other existing sensory QoS protocols.

Effective classification and analysis of semantic contents are very important for the content-based indexing and retrieval of video database. Our research attempts to classify movie clips into three groups of commonly elicited emotions, namely excitement, joy and sadness, based on a set of abstract-level semantic features extracted from the film sequence. In particular, these features consist of six visual and audio measures grounded on the artistic film theories. A unique sieving-structured neural network is proposed to be the classifying model due to its robustness. The performance of the proposed model is tested with 101 movie clips excerpted from 24 award-winning and well-known Hollywood feature films. The experimental result of 97.8% correct classification rate, measured against the collected human-judges, indicates the great potential of using abstract-level semantic features as an engineered tool for the application of video-content retrieval/indexing.

Reducing the power dissipation for LDPC code decoder is a major challenging task to apply it to the practical digital communication systems. In this paper, we propose a low power LDPC code decoder architecture based on an intermediate message-compression technique which features as follows: (i) An intermediate message compression technique enables the decoder to reduce the required memory capacity and write power dissipation. (ii) A clock gated shift register based intermediate message memory architecture enables the decoder to decompress the compressed messages in a single clock cycle while reducing the read power dissipation. The combination of the above two techniques enables the decoder to reduce the power dissipation while keeping the decoding throughput. The simulation results show that the proposed architecture improves the power efficiency up to 52% and 18% compared to that of the decoder based on the overlapped schedule and the rapid convergence schedule without the proposed techniques respectively.

Delay jitter degrades the quality of delay-sensitive live media streaming. We investigate the use of multipath transmission with two paths to reduce delay jitter and, in this paper, propose a nearly equal delay path set configuration (NEED-PC) scheme that further improves the performance of the multipath delay jitter reduction method for delay-sensitive live media streaming. The NEED-PC scheme configures a pair of a maximally node-disjoint paths that have nearly equal path delays and satisfy a given delay constraint. The results of our simulation experiments show that path sets configured by the NEED-PC scheme exhibit better delay jitter reduction characteristics than a conventional scheme that chooses the shortest path as the primary path. We evaluate the performance of path sets configured by the NEED-PC scheme and find that the NEED-PC scheme reduces delay jitter when it is applied to a multipath delay jitter reduction method. We also investigate the trade-off between reduced delay jitter and the increased traffic load incurred by applying multipath transmission to more flows. The results show that the NEED-PC scheme is practically effective even if the amount of additional redundant traffic caused by using multipath transmission is taken into account.

In optical burst switching (OBS) networks, burst with different numbers of hops experience unfairness in terms of the burst loss probability. In this paper, we propose a preemptive scheme based on the number of transit hops in OBS networks. In our proposed scheme, preemption is performed with two thresholds; one is for the total number of hops of a burst and the other is for the number of transit hops the burst has passed through. We evaluate the performance of the scheme by simulation, and numerical examples show that the proposed scheme improves the fairness among the bursts with different numbers of hops, keeping the overall burst loss probability the same as that for the conventional OBS transmission without preemption.