Pricing model for internet-based multi-class Video-On-Demand(VOD) services

This paper presents an optimal Pay-Per-View (PPV) price decision model for maximizing an Internet based Video-On-Demand (VOD) service provider’s revenues, taking into account the service provider’s service quality and consumers’ willingness to pay. The model considers multi-class VOD services with differentiated qualities and determines the optimal price for each class through simulations. The simulation results show that as long as all the multi-class services have non-zero demands, the differential pricing system provides more revenues than the uniform pricing system that prevails in the current VOD market. To test the robustness of the model, simulations were performed with gradually increasing customer demands or system workloads. The simulation results show that even with substantial customer demands or system workloads, self-adjustment mechanism of the model works and the system reaches a stable status in equilibrium. This paper also presents a numerical example of guaranteeing Quality-of-Service (QoS) through pricing strategies as a short-term measure.     

Technologies to improve photo-sensitivity and reduce VOD shuttervoltage for CCD image sensors

New technologies to increase the photo-sensitivity and reduce the shutter voltage of the vertical over-flow-drain (VOD) have been developed for CCD image sensors. The photo-sensitivity was increased 40% by forming an anti-reflection film over the photodiode and reducing the thickness of the p⁺-layer formed at the photodiode surface. The VOD shutter voltage was reduced from 31 to 18 V by using an epitaxially grown substrate with double impurity concentration layers     

Optimal video placement scheme for batching VOD services

Advances in broadband technology are generating an increasing demand for video-on-demand (VOD) applications. In this paper, an optimal video placement scheme is proposed for a batching VOD system with multiple servers. Given a specified requirement of the blocking probability, an optimal batching interval is derived and the corresponding file placement is obtained by hybrid genetic algorithm. It is demonstrated that the specified requirement on blocking probability is satisfied, while both batching interval and server capacity usage are minimized simultaneously.     

AVS trick modes for PVR and VOD services

AVS1-P2 is a recently completed video compression standard developed by the Audio and Video Coding Standard (AVS) Workgroup of China. The standard promises comparable compression efficiency to the H.264/MPEG-4 AVC video codec with lower implementation complexity and royalty fees. AVS1-P2 is the Chinese next generation national video coding standard with an increasing amount of industrial importance as it is being required for different applications and services. It is expected that AVS1-P2 will be prominent in emerging Chinese digital video application markets, especially for personal video recorder (PVR) and video on demand (VOD).This paper discusses how trick modes for PVR and VOD can be performed with AVS1-P2 content. It begins with generating an index table to facilitate AVS1-P2 trick modes followed by a discussion of basic and advanced trick modes. Next, the minimum decoder speed and display frame buffer requirements are analyzed for smooth trick play, especially for 1× rewind. VOD stream delivery strategies for various trick modes and transitions are then discussed. Finally, an overview of other topics that may affect implementation such as content protection and encoding is provided. Many of the discussions are also applicable to other video coding standards like MPEG-2, H.264/AVC, etc.     

Message waiting time performance for meteor-burst communicationsystems

The performance is investigated of the meteor-burst channel in terms of the waiting time required to reliably transmit a message of length N bits. Two modulation techniques are considered. The first is the traditional fixed-rate modulation scheme where the modem operates at a constant bit rate whenever the channel is available for message traffic. The second is an adaptive modulation method where the channel symbol rate varies continuously to match the time-varying signal-to-noise ratio at the receiver. Upper and lower bounds on waiting time for the general case are derived using probabilistic arguments. Novel closed-form expressions for waiting time and optimal bit rate are derived for the fixed-rate modem. Bounds on mean waiting time are derived for the adaptive-symbol-rate modem. It is shown that for fixed-rate modems operating at the optimal bit rate and for adaptive modems operating at a minimum bit rate equal to this rate, the improvement in mean waiting time can never exceed a factor of two     

The waiting time distribution for a TDMA model with a finite buffer and state-dependent service

We obtain detailed analytic formulas for the density and probability distribution of the waiting time in a time-division multiple-access (TDMA) model with a finite buffer and state-dependent service. On successive intervals of length equal to the duration of a slot, the density is expressed as a linear combination of beta densities with positive coefficients. A recursive scheme, obtained by a matrix-analytic derivation, allows for the highly efficient computations of the coefficient sequences. An expression for the mean waiting time is derived using the classical queueing formula L=/spl lambda/W. We also demonstrate that our methodology provides a concise treatment of various special cases that have been studied over the past half century.     

An approximation for waiting time tail probabilities in multiclasssystems

This article proposes a simple exponential approximation for waiting time tail probabilities in multiclass systems. The approximation is evaluated by making comparisons with simulation results, which show that the proposed approximation is adequate     

A differentiated optical services model for WDM networks

This article addresses the issues of scalable end-to-end QoS in metropolitan DWDM networks serving as transit networks for IP access networks. DWDM offering a few wavelengths has been deployed in the past in backbone networks to upgrade point-to-point transmission where sharing is based on coarse granularity. This type of DWDM backbone network, offering a few light-paths, provides no support for QoS services traversing the network. As DWDM networks with larger numbers of wavelengths penetrate the data-centric metro environment, specific IP service requirements such as priority restoration, scalability, dynamic provisioning of capacity and routes, and support for coarse-grain QoS capabilities will have to be addressed in the optical domain in order to achieve end-to-end QoS over a DWDM network. We propose a QoS service model in the optical domain called differentiated optical services (DoS) based on a set of optical parameters that captures the quality and reliability of the optical lightpath     

Double-sided two-way ranging algorithm to reduce ranging time

In this Letter we propose a novel ranging algorithm for the asynchronous location positioning system. The main idea of the proposed algorithm is to reply with multiple acknowledgement packets to a single ranging request. The ranging algorithm reduces the number of packets used in ranging process and improves the ranging accuracy at the same time.     

构建城域网络视频点播系统方案分析

分析了应用于宽带城域网的商用化视频点播系统的技术要点，提出了视频服务器的评价标准，并设计了适合于宽带城域网应用的分层分布式视频点播系统的结构。     

Retiming synchronous data-flow graphs to reduce execution time

Many common iterative or recursive DSP applications be can represented by synchronous data-flow graphs (SDFGs). A great deal of research has been done attempting to optimize such applications through retiming. However, despite its proven effectiveness in transforming single-rate data-flow graphs to equivalent DFGs with smaller clock periods, the use of retiming for attempting to reduce the execution time of synchronous DFGs has never been explored. In this paper, we do just this. We develop the basic definitions and results necessary to express and study SDFGs. We review the problems faced when attempting to retime an SDFG in order to minimize clock period and then present algorithms for doing this. Finally, we demonstrate the effectiveness of our methods on several examples     

A control method to reduce the standard deviation of flow time inwafer fabrication

This paper proposes a control, method for reducing flow time variability in a wafer fabrication facility with multiple wafer types. We employ stochastic Petri nets to model and analyze the machine module, and define operation due dates using a novel utilization index metric. An operation due date (OPNDD) rule for lot dispatch is proposed and evaluated against other lot dispatch policies     

A new method to reduce addressing time in a large AC plasma displaypanel

To replace the dual scan system by single scan in large ac plasma display panel (PDP), the addressing time should be reduced by modifying cell structure and/or driving circuits. Moreover, the luminance of the PDP can also be increased with the decrease in the addressing time. In this paper, we suggest the bus and address electrodes with triangular protruding tips in order to reduce the addressing time. Moreover, the addressing time of the ac PDP with these electrodes was investigated experimentally with address and display period separated (ADS) driving method. The experimental results show that the addressing time can be reduced more than 30% compared with the conventional type by modifying the electrodes without reducing the luminance of the PDP     

缩短舰载光电跟踪仪调舷时间的研究

光电跟踪仪调舷时间的缩短意味着武器系统反应时间的减小,给后续火控、武器攻击争取了先发的时间。对于光电跟踪仪这种跟踪系统来说,快速反应是它们的致命点,而大角度调舷时间占武器反应时间的一大部分,因此,如何快速调舷在工程上是个很有意义的课题。文中通过合理选择调舷曲线对调舷速度进行改进,并通过实验验证了缩短调舷时间研究的可行性。     

VOD系统的一种可行的解决方法--分时点播电视

对现有VOD系统的一些解决方法的可行性进行研究,并提出一种新的真点播电视（TVOD）系统的实现方案,即分时点播电视。这种类似于多任务系统的解决方案能有效地降低TVOD系统进入实用的成本和价格,并能很好地满足用户要求。     

Transient behaviour for a continuous time parameter system with finite waiting room

For a continuous time parameter system with finite waiting room, the difference equations satisfied by the Laplace transforms of the state probabilities at finite time are solved and the state probabilities have been obtained. The method economizes in algebra and the simple closed form of the state probabilities is used to obtain some important characteristics of the system.     

Adaptive wireless thin‐client model for mobile computing

The thin‐client computing model has the potential to significantly increase the performance of mobile computing environments. By delivering any application through a single, small‐footprint client (called a thin client) implemented on a mobile device, it is possible to optimize application performance without the need for building wireless application gateways. We thus present two significant contributions in the area of wireless thin‐client computing. Firstly, a mathematical performance model is derived for wireless thin‐client system. This model identifies factors that affect the performance of the system and supports derivation and analysis of adaptation strategies to maintain a user‐specified quality of service (QoS). Secondly, a proxy‐based adaptation framework is developed for wireless thin‐client systems, which dynamically optimizes performance of a wireless thin client via dynamically discovered context. This is implemented with rule‐based fuzzy logic that responds to variations in wireless link bandwidth and client processing power. Our fuzzy inference engine uses contextual data to dynamically optimize tradeoffs among different quality of service parameters offered to the end users. Additionally, our adaptation framework uses highly scalable wavelet‐based image coding to provide scalable QoS that can degrade gracefully. Our thin‐client adaptation framework shields the user from ill effects of highly variable wireless network quality and mobile device resources. This improves performance of active applications, in which the display changes frequently. Further, active application behaviour may produce high transmission latency for screen updates, which can adversely affect user perception of QoS, resulting in poor interactivity. We report measured adaptive performance under realistic mobile device and network conditions for several different clients and servers. Copyright © 2008 John Wiley & Sons, Ltd.     

Average waiting time for mobile radio terminals accessing abatch-processing dispatcher by satellite

To minimise call set-up overheads, a demand assignment scheme for mobile radio networks over a satellite has been proposed, in which calls are processed by the network dispatcher in batches. The letter examines the average waiting time for calls to be processed under this service discipline     

A case for relative differentiated services and the proportionaldifferentiation model

Internet applications and users have very diverse quality of service expectations, making the same-service-to-all model of the current Internet inadequate and limiting. There is a widespread consensus today that the Internet architecture has to extended with service differentiation mechanisms so that certain users and applications can get better service than others at a higher cost. One approach, referred to as absolute differentiated services, is based on sophisticated admission control and resource reservation mechanisms in order to provide guarantees or statistical assurances for absolute performance measures, such as a minimum service rate or maximum end-to-end delay. Another approach, which is simpler in terms of implementation, deployment, and network manageability, is to offer relative differentiated services between a small number of service classes. These classes are ordered based on their packet forwarding quality, in terms of per-hop metrics for the queuing delays and packet losses, giving the assurance that higher classes are better than lower classes. The applications and users, in this context, can dynamically select the class that best meets their quality and pricing constraints, without a priori guarantees for the actual performance level of each class. The relative differentiation approach can be further refined and quantified using the proportional differentiation model. This model aims to provide the network operator with the “tuning knobs” for adjusting the quality spacing between classes, independent of the class loads. When this spacing is feasible in short timescales, it can lead to predictable and controllable class differentiation, which ore two important features for any relative differentiation model. The proportional differentiation model can be approximated in practice with simple forwarding mechanisms (packet scheduling and buffer management) that we describe     

A composite model of product development effectiveness: application to services

This paper explores the extent to which an enlarged, generic version of a "composite" model of concurrent product development previously tested for goods industries also applies to services. The model is comprised of four types of building blocks commonly used in theories of organization design. The operating core of the model includes a troika of practice sets dealing with the organization of cross-functional teams, discipline by structured development processes, and the use of enabling tools/technologies. Concurrent strategy focuses core operations on fast, reiterative cycles of product development. The model postulates that synergy among its constructs have an impact on product development effectiveness. This postulate is tested by multiple regression analysis of 62 large service enterprises in the New York area. All four components of the model had main effects on performance measured as time compression and cost reduction in product development, signature indicators of the effectiveness of concurrent methods of product development. Interaction effects were observed among the constructs of strategy, organization, and process, which suggest synergies. However, tools/technologies lacked significant interactions. With this exception, the results for services parallel those of other studies of goods industries. These findings suggest that concurrent methods of product development are robust, as well as reliable. A generic model of product development is important for managing innovation because goods and services are increasingly commingled in many enterprises and sold as a bundle. Thus, the four building blocks of the model are important for managers to consider deploying in synergistic ways to speed time to market and achieve cost efficiencies.