In this paper, we present a CDN (Content Delivery Network) architecture for mobile streaming service in which content segmentation, request routing, pre-fetch scheduling, and session handoff are controlled by SMIL (Synchronized Multimedia Integration Language) modification. In this architecture, mobile clients simply follow modified SMIL files downloaded from a portal server; these modifications enable multimedia content to be delivered to the mobile clients from the best surrogates in the CDN. The key components of this architecture are 1) content segmentation with SMIL modification, 2) on-demand rewriting of URLs in SMIL, 3) pre-fetch scheduling based on timing information derived from SMIL, and 4) SMIL updates by SOAP (Simple Object Access Protocol) messaging for session handoffs due to client mobility. This architecture enhances streaming media quality for mobile clients while utilizing network resources efficiently and supporting client mobility in an integrated and practical way. The current status of our prototype on a mobile QoS testbed "MOBIQ" is also reported in this paper.

To support UDP-based real-time multimedia applications over the Internet, it is necessary to provide a certain amount of bandwidth within the network so that the performance of the applications will not be seriously affected during periods of congestion. Since the flow rates of some of these applications do not back off during periods of congestion, it is also necessary to protect flow-controlled TCP flows from unresponsive or aggressive UDP flows. To achieve these goals, we propose a simple queue policy to support multimedia applications, called threshold-based queue management (TBQM). TBQM isolates UDP flows efficiently from TCP flows to protect TCP flows while supporting bandwidth requirements of UDP applications that require QoS. In addition, TBQM supports drop fairness between flows without maintaining per-flow state. We also present some experimental results to show that the proposed queue policy works well.

Takine investigated the continuous time queueing system with single server and Markovian arrival streams (MAS) where service times of customers depend on the states of the underlying Markov chain immediately before and after arrivals and may differ from one another among streams. In this paper, we consider the discrete version of Takine's model. Since a MAS can be used to model the correlated traffics of several classes, we consider the discrete time queueing system with MAS as an input traffic. Moreover packets from different classes of traffic may require different service times. So service times of customers which are different from one another among streams and may depend on the states of the underlying Markov chain immediately before and after arrivals, are also considered. We obtain the distribution of the workload in the system using Neuts' matrix analytic method. Based on this result, we obtain the distributions of the actual waiting time and the sojourn time of a customer of each class and the joint distribution of the numbers of customers of each class. We also provide a recursion formula for computing the joint queue length distribution. We give an application to multimedia conference system and numerical example.

In this paper, we present an Internet personal live-broadcasting server system. Our solution is not only for experts but also for amateur users who want to broadcast using simple multimedia equipment. For scalable broadcasting services, we developed multiple-channel establishment and channel expansion. Concurrent services for a large number of broadcasting channels are effectively provided. Also, the capacity of channels can be expanded as the number of participants increases. Furthermore, for the sake of complete live broadcasting with high-quality transmission, the system supports both TCP (transmission control protocol) and UDP (user datagram protocol) according to the status of network environments as well as the received packet loss in the user system. The performance of the system is effectively evaluated at such practical commercial sites as well-known community and E-business sites.

A 12.8GOPS/2.1GFLOPS that operates at 533 MHz, and which is equipped with an 8-way embedded VLIW processor fabricated with 6-layer Cu and 1-layer Al metal 0.11 µm CMOS process technology is introduced in this paper. The processor is also equipped with a 4-way integer pipeline, a 4-way floating/media pipeline, and separate 32 KB 4-way set associative instruction and data caches. It is also equipped with instruction fetch prediction, and non-aligned dual data load/store mechanisms. The performance evaluation that was successfully conducted using the MPEG2 IDCT routine and JPEG decoding program shows that it offers twice the performance of the previous work . 10.4 M transistors are integrated on a 7.8 mm 7.8 mm die. The chip consumes 2.5 W at 533 MHz.

In the past, enhancement techniques for the end-to-end quality of a networked application were studied by looking at each individual layer. Examples of such techniques include the error resilience/concealment methods in the application layer, the FEC/ARQ in the transport layer, and the Quality of Service (QoS) techniques in the network layers. However, an integrated approach that would look across all related layers had yet to be investigated. This paper proposes an approach that combines priority-aware video packetization, adaptively used layered FEC, and QoS controlled networks such as IntServ and DiffServ in order to provide an efficient end-to-end quality in layered streaming video. The combination is more efficient in terms of a simple network price mechanism, that is, in getting the best end-to-end quality under a given total cost constraint. Our proposed approach in DiffServ with video packet (VP) data-splitting and layered FEC guarantees minimal service quality in a scalable and cost effective manner without introducing resource reservation. For video, we also propose performance metrics such as corrupted/frozen frame ratio (CFR, FFR). These provide objective metrics like PSNR as well as a measurement for subjective perceptions. Our approach, which combines related layers such as video coding, transport, and network, has yielded results that have proven to be more cost-effective and practical than the supporting network QoS.

The ATM-ABR service category provides minimum cell rate (MCR) guarantees and robust connections even with insufficient network resources. Recently proposed rate-management algorithms for supporting multimedia applications over ABR mainly aim at minimizing the cell loss and delay. However, jitter is also an important element of QoS for multimedia applications. In this paper, we focus our attention on the arrival point of the critical cell corresponding to the end of data packet and propose a simple cell scheduling scheme for source node to reduce the jitter on application level over the ATM-ABR service class. In our proposed method, critical cells are delayed intentionally and the packet stream at application level becomes smooth. We verify the effectiveness of our proposed algorithm by an analytical model and simulation. From those results, we find that our proposed scheduling algorithm is effective in reducing the application level jitter even when the tagged cell stream is transmitted along the path with multiple nodes.

A key problem under imperfect power control in multimedia DS-CDMA networks is how to guarantee the differentiated outage probabilities of different traffic classes resulted from the uncertainty of received powers. In addition, in order to utilize the scarce wireless resource efficiently, as many users as possible should be admitted into the network while providing guaranteed quality-of-service support for them. In this work, a call admission control scheme, Differentiated Outage Probabilities CAC or DOP-CAC, is proposed to achieve the above goals for imperfectly power-controlled multimedia CDMA networks. Two important features of CDMA systems are considered in our scheme: one is the power multiplexing among bursty traffics and the other is the power allocation scheme employed at the physical layer. The validity and efficiency of DOP-CAC are verified by numerical examples. Two power allocation schemes, Limited Optimal Power Allocation (LOPA) proposed in [3] and Quasi-Optimal Power Allocation (QOPA) we proposed in [6], are considered respectively and compared in the performance evaluation of DOP-CAC. The results show that DOP-CAC achieves much better resource utilization under QOPA than it does under LOPA. By employing QOPA at the physical layer and DOP-CAC at the link layer, our work suggests a high efficiency solution for QoS support of multimedia traffic under imperfect power control environment.

In this paper, we propose a medium access control (MAC) protocol for multimedia code division multiple access (CDMA) communications. In the proposed protocol, a base station (BS) estimates the instantaneous number of simultaneously transmitted packets in the future slots with exploiting a stochastic property of traffic. In order to carry out this estimation, we employ an adaptive algorithm. We evaluate the performance of the proposed protocol by comparing that with two different cases. One is no estimation case and the other is perfect estimation case. From these results, we clarify the advantage of the proposed MAC protocol.

In this paper, a VLSI architecture for lifting-based discrete wavelet transform (LDWT) is presented. Our architecture folds the computations of all resolution levels into the same low-pass and high-pass units to achieve higher hardware utilization. Due to the regular and flexible structure of the design, its area is independent of the length of the 1-D input sequence, and its latency is independent of the number of resolution levels. For the computations of analysis process of N-sample 1-D 3-level LDWT, our design takes about N clock cycles and requires 2 multipliers, 4 adders, and 22 registers. It is fabricated with TSMC 0.35-µm cell library and has a die size of 1.21.2 mm2. The power dissipation of the chip is about 0.4 W at the clock rate of 80 MHz.

This paper presents efficient file management of a hard disk drive embedded digital satellite receiver. The digital broadcasting technology enables multimedia access via broadcasting systems. The amount of digital data to be processed is increased remarkably as compared to the previous analog broadcasting environments. The efficient digital data storage and management technology are discussed in this paper to cope with these changes. The DSR uses a new file system that is designed by considering disk cluster sizes and limited memories in the system, which is more appropriate than that of general Personal Computers. The proposed system enables us to watch broadcasting and to manage multimedia data efficiently.

Write linear density limit is defined to analyze the magnetic recording process in computer hard disk drives at extremely high recording densities. The digital data with pseudo random sequences are recorded numerically in longitudinal media at different densities by a micromagnetic simulation model. A thin film write head and an ideal GMR read head are utilized in the record and read-back process, respectively. A novel method has been utilized to study the write linear density limit: the simulated read back voltage and the respected linear superposed pulses are compared to find the distortion in the record process. When a severe distortion shows up, the corresponding linear density is considered as the write linear density limit. By the novel method, the write linear density limit is analyzed with different parameters of the recording media.

The effect of NiP as a seed layer for the [Co/Pd]n multilayer perpendicular recording media was studied. It was found that a thin layer of 2 nm NiP inserted between the FeCoC soft magnetic underlayer and the [Co/Pd]n recording layer improved the magnetic properties such as coercivity, squareness and nucleation field. These improvements may be due to the enhanced grain isolation promoted by the NiP seed layer, as well as the lower surface roughness of the NiP seed layer. Read/write test using Guzik spin stand with a ring-type head showed a D50 value 220 kFCI in the roll-off curve. The magnetic transitions recorded up to 390 kFCI for [Co/Pd]n media with the NiP seed layer can be observed clearly with MFM.

The mobile system has been taking an important role as the infrastructure of the advanced information society. First, as the telecommunication infrastructure, it enabled us to communicate with anybody, anytime, and anywhere. Next, as the multimedia infrastructure, it enabled us to send, receive, and retrieve data. Now, as the IT infrastructure, it enables us to purchase commodities, transact business, and enjoy entertainment on-line. The mobile system has morphed into the third generation in almost two decades. Several mobile services have been introduced in each generation to feature the above infrastructures. This paper describes the authors' views on how mobile services have contributed to the advance of the information society in the past three generations. It also discusses what role the future mobile system should take in realizing the wealthier information society.

In recent years, perpendicular magnetic recording have progressed rapidly. It will not be long before perpendicular magnetic recording is put into practical use. However there have been few tools contributing to the optimum design of perpendicular magnetic recording media and heads except computer simulations. The authors have introduced a simple method based on the concept of self-consistent magnetization to analytically predict a transition parameter in terms of parameters of recording media and writing heads. Moreover we have discussed the origin of media noise by using a time-domain analysis of readout voltage and Voronoi cell model analysis. In this paper, main parameters to realize high bit density recording over 100 Gbit/inch2 is discussed first through these methods, and then the current status, the future problems and the prospects in perpendicular magnetic recording technology are described.

Patterned magnetic media are promising to be the next generation recording media for computer hard disk drives to go beyond the density of 100 Gb/in2. A micromagnetic simulation model is set up to study the magnetic property as well as the recording process in patterned media. The patterned medium studied in this paper is an array of pillar magnetic particles with a perpendicular anisotropy. A pole record head as well as a thin film head are utilized in the simulated recording process. The diameter of the magnetic pillars is chosen as 20 nm, the bit length takes the values of 30 nm, 40 nm and 50 nm, with respect to an ideal areal density of 258 Gb/in2, 459 Gb/in2 and 717 Gb/in2. The magnetic signal and noise recorded in a series of patterned media are analyzed at different recording densities with the two types of record heads.

Co-containing ferrite thin-film media deposited by a reactive-ECR-sputtering at a low substrate temperature of 150 degree Celsius were oxidized by ECR plasma. The magnetic properties and recording characteristics of the media were improved by the oxidation with maintaining a smooth surface. The media showed high D50 of 203 kFRPI in MIG head recording and reproduction. The Co-containing ferrite thin-film is feasible to be used as a protective overcoat layer.

The effects of an intermediate layer of carbon on the structural and magnetic properties of a CoCrPtTa recording layer were investigated in double-layered perpendicular magnetic recording media with either amorphous CoTaZr or crystalline FeAlSi as soft magnetic backlayers. Introducing a thin layer of carbon enhanced the perpendicular magnetic anisotropy with both soft magnetic backlayers. This result suggests that the introduction of a non-magnetic intermediate layer is useful in improving the basic magnetic properties of the CoCr-alloy recording layer even when an amorphous soft magnetic backlayers is used.

Today, many audiovisual delivery systems, including video streaming and video conferencing, are being developed for use over a range of networking technologies, the differing characteristics of which pose problems for service level interoperability. Multimedia transcoding is one means to provide interoperability between different types of audiovisual terminals and between terminals that connect to different networks. In this paper, we will present a multimedia transcoder system, which provides interoperability between video conferencing terminals on IP networks and mobile terminals on mobile networks.

Emerging real-time and multimedia applications in IP over ATM networks are becoming an indispensable part of the networking world. Considering the different and essential natures of IP and ATM, it seems that they complement each other. Although several approaches have been proposed for IP and ATM integration, so far a key problem (i.e., Quality of Service support) in foreseeable future networking applications remains unsolved. This paper describes a new extension to Classical IP and ARP over ATM (CLIP) protocol, Real-time and Multimedia services using CLIP (RMCLIP), providing ATM service classes to the IP end users. It defines that different service classes are mapped to the associated IP addresses. It enables different IP end user applications (e.g., real-time video, voice and data) to obtain their own dedicated VCs.