Comparative performance evaluation of CAR systems based on mobile phones and feature tracking

Collaborative Augmented Reality (CAR) systems based on mobile phones have experienced a huge expansion last years, since the hardware features of most mobile phones provide excellent multimedia services and wireless network capabilities. In previous works, we improved the performance of large-scale CAR systems based on mobile phones that use fiducial marker tracking. However, CAR systems based on natural feature tracking have just emerged, changing the way in which Augmented Reality applications work. In this paper, we propose the performance evaluation of CAR systems based on feature tracking when using mobile phones, and their comparison with CAR systems based on fiducial marker tracking. The evaluation of the whole CAR system includes the rendering of the virtual environment with Unity3D. The purpose is to provide the reader with a reference about the performance that can be achieved with each kind of CAR system. The evaluation results of client devices show that they work faster with natural feature (commonly denoted as markerless) tracking than with fiducial marker tracking, regardless of the phone model and the operating system considered. The evaluation results of the whole CAR system show that natural feature tracking provides similar performance than fiducial marker tracking when the system reaches saturation. However, the use of natural feature tracking allows better performance for low workloads or when the system approaches saturation, since, it provides similar response times at the cost of increasing the percentage of CPU utilization in the server, instead of dropping messages. These results validate natural feature tracking as the best option for CAR systems based on mobile phones.     

Uses of Prolog in implementation of expert systems

Prolog is becoming a popular language in A. I. applications and particularly in the implementation of knowledge based expert systems. We have identified three different uses of Prolog: (1) building expert systems directly in ordinary Prolog, (2) using Prolog as the implementation language for an higher level of interpretation, and (3) extending Prolog with suitable features and directly using it. In this paper, we define the three uses in more details, compare them, and cite some concrete examples.     

Guidelines for Selecting Hadoop Schedulers Based on System Heterogeneity

Hadoop has been developed as a solution for performing large-scale data-parallel applications in Cloud computing. A Hadoop system can be described based on three factors: cluster, workload, and user. Each factor is either heterogeneous or homogeneous, which reflects the heterogeneity level of the Hadoop system. This paper studies the effect of heterogeneity in each of these factors on the performance of Hadoop schedulers. Three schedulers which consider different levels of Hadoop heterogeneity are used for the analysis: FIFO, Fair sharing, and COSHH (Classification and Optimization based Scheduler for Heterogeneous Hadoop). Performance issues are introduced for Hadoop schedulers, and experiments are provided to evaluate these issues. The reported results suggest guidelines for selecting an appropriate scheduler for Hadoop systems. Finally, the proposed guidelines are evaluated in different Hadoop systems.     

Continuous scanning leaky‐wave antenna utilizing second‐mode spoof surface plasmon polaritons excitation

Continuous scanning leaky‐wave antenna (LWA) based on second‐mode spoof surface plasmon polaritons (SSPPs) excitation has been proposed and validated in this article. Different from the existing modulation methods, connecting axisymmetric rectangular modulation is adopted to excite the ?first harmonic. In this way, the slow‐wave bound on the surface of the transmission line is converted into a radiation wave in space. To the authors' knowledge, this is the first presentation of LWA design utilizing second‐mode SSPPs excitation. In the range from 5.0 to 9.0 GHz, the proposed LWA realizes continuous scanning from ?54° ~ 11° with a quasi‐omnidirectional beam in the vertical plane. A prototype of the proposed antenna is fabricated and measured, and the measured results show good agreement with the simulated. The proposed LWA has potential applications in communication systems and radars.     

Session-based security enhancement of RFID systems for emerging open-loop applications

Radio frequency identification (RFID) is an important technique used for automatic identification and data capture. In recent years, low-cost RFID tags have been used in many open-loop applications beyond supply chain management, such as the tagging of the medicine, clothes, and belongings after the point of sales. At the same time, with the development of semiconductor industry, handheld terminals and mobile phones are becoming RFID-enabled. Unauthorized mobile RFID readers could be abused by the malicious hackers or curious common people. Even for authorized RFID readers, the ownership of the reader can be transferred and the owners of the authorized mobile reader may not be always reliable. The authorization and authentication of the mobile RFID readers need to take stronger security measures to address the privacy or security issues that may arise in the emerging open-loop applications. In this paper, the security demands of RFID tags in emerging open-loop applications are summarized, and two example protocols for authorization, authentication and key establishment based on symmetric cryptography are presented. The proposed protocols adopt a timed-session-based authorization scheme, and all reader-to-tag operations are authorized by a trusted third party using a newly defined class of timed sessions. The output of the tags is randomized to prevent unauthorized tracking of the RFID tags. An instance of the protocol A is implemented in 0.13-μm CMOS technology, and the functions are verified by field programmable gate array. The baseband consumes 44.0 μW under 1.08 V voltage and 1.92 MHz frequency, and it has 25,067 gate equivalents. The proposed protocols can successfully resist most security threats toward open-loop RFID systems except physical attacks. The timing and scalability of the two protocols are discussed in detail.     

Real-time and robust hand tracking with a single depth camera

In this paper, we introduce a novel, real-time and robust hand tracking system, capable of tracking the articulated hand motion in full degrees of freedom (DOF) using a single depth camera. Unlike most previous systems, our system is able to initialize and recover from tracking loss automatically. This is achieved through an efficient two-stage k-nearest neighbor database searching method proposed in the paper. It is effective for searching from a pre-rendered database of small hand depth images, designed to provide good initial guesses for model based tracking. We also propose a robust objective function, and improve the Particle Swarm Optimization algorithm with a resampling based strategy in model based tracking. It provides continuous solutions in full DOF hand motion space more efficiently than previous methods. Our system runs at 40 fps on a GeForce GTX 580 GPU and experimental results show that the system outperforms the state-of-the-art model based hand tracking systems in terms of both speed and accuracy. The work result is of significance to various applications in the field of human–computer-interaction and virtual reality.     

Puzzle - an efficient,compression independent video encryption algorithm

Real-time video streams require an efficient encryption method to ensure their confidentiality. One of the major challenges in designing a video encryption algorithm is to encrypt the vast amount of video data in real-time to satisfy the stringent time requirements. Video encryption algorithms can be classified according to their association with video compression into joint compression and encryption algorithms and compression-independent encryption algorithms. The latter have a clear advantage over the former regarding the incorporation into existing multimedia systems due to their independence of the video compression. In this paper we present the compression-independent video encryption algorithm Puzzle, which was inspired by the children game jigsaw puzzle. It comprises two simple encryption operations with low computational complexity: puzzling and obscuring. The scheme thereby dramatically reduces the encryption overhead compared to conventional encryption algorithms, such as AES, especially for high resolution video. Further outstanding features of Puzzle are a good trade-off between security demands and encryption efficiency, no impairment on video compression efficiency, and an easy integration into existing multimedia systems. This makes Puzzle particularly well-suited for these security-sensitive multimedia applications, such as videoconferencing, where maximal security and minimal encryption overhead are desired simultaneously.     

融合通信系统中分布式存储引擎的研究

融合通信是当今计算机应用领域研究热点之一,人们对融合通信系统中应用服务的要求也越来越高.在数据存取方面,基于传统关系型数据库或者基于传统文件系统的存储方式已经越来越不能满足应用的需求.随着Hadoop技术以及相关子系统的发展,分布式存储的优势日渐明显.因此,本文在分析HBase、Hive各自特点及其体系结构的基础上,结合融合通信具体项目提出了基于HBase-Hive集成设计的存储引擎设计方法,以此来解决融合通信系统中数据安全性、数据获取效率等方面不满足的情况.通过对比实验表明,该设计方案提高系统数据查询获取效率,也为后续数据挖掘方面的开发做好准备.     

Sliding mode control as binary‐based quantizers

In recent years, sliding mode quantizers (SMQs), where signals are converted to switching signals represented by sequence of binary values ?1's and +1's, are increasingly being used in various applications including control of power converters, networked control systems (NCSs), one‐bit control processing, etc. This paper derives the stability conditions of both continuous and discrete‐time switched control systems which are embedded with SMQs and quasi‐sliding mode quantizers (QSMQs), respectively. The optimal conditions of both SMQ and QSMQ, which assure that their outputs (binary values) optimally approximate their inputs, are established. The results of theoretical analysis are validated through numerical simulation.     

Parallelizing Complex Streaming Applications on Distributed Scratchpad Memory Multicore Architecture

Multicore processors can provide sufficient computing power and flexibility for complex streaming applications, such as high-definition video processing. For less hardware complexity and power consumption, the distributed scratchpad memory architecture is considered, instead of the cache memory architecture. However, the distributed design poses new challenges to programming. It is difficult to exploit all available capabilities and achieve maximal throughput, due to the combined complexity of inter-processor communication, synchronization, and workload balancing. In this study, we developed an efficient design flow for parallelizing multimedia applications on a distributed scratchpad memory multicore architecture. An application is first partitioned into streaming components and then mapped onto multicore processors. Various hardware-dependent factors and application-specific characteristics are involved in generating efficient task partitions and allocating resources appropriately. To test and verify the proposed design flow, three popular multimedia applications were implemented: a full-HD motion JPEG decoder, an object detector, and a full-HD H.264/AVC decoder. For demonstration purposes, SONY PlayStation \(^{\circledR }\) 3 was selected as the target platform. Simulation results show that, on PS3, the full-HD motion JPEG decoder with the proposed design flow can decode about 108.9 frames per second (fps) in the 1080p format. The object detection application can perform real-time object detection at 2.84 fps at \(1280 \times 960\) resolution, 11.75 fps at \(640 \times 480\) resolution, and 62.52 fps at \(320 \times 240\) resolution. The full-HD H.264/AVC decoder applications can achieve nearly 50 fps.     

A formal framework for service modeling and prototyping

Service-oriented Computing is rapidly gaining importance across several application domains due to its capability of composing autonomous and loosely-coupled services. In order to support the engineering of service-oriented software applications, foundational theories, service modeling notations, evaluation techniques fully integrated in a pragmatic software engineering approach are required. This article introduces a framework for modeling and prototyping service-oriented applications. The framework consists of a precise and executable language, SCA-ASM, for model-based design, and of a tool for early and quick design evaluation of service assemblies. The language combines the OASIS/OSOA standard Service Component Architecture (SCA) capability of modeling and assembling heterogeneous service-oriented components in a technology agnostic way, with the rigor of the Abstract State Machine (ASM) formal method able to model notions of service behavior, interactions, orchestration, compensation and context-awareness in an abstract but executable way. The tool is based on existing execution environments for ASM models and SCA applications. An SCA-ASM model of a service-oriented component, possibly not yet implemented in code or available as off-the-shelf, can be (i) simulated and evaluated offline, i.e. in isolation from the other components; or (ii) executed as abstract implementation (or prototype) together with the other components implementations according to the chosen SCA assembly. As proof of concept, a case study taken from EU research projects has been considered to show the functionalities and potentialities of the proposed framework.     

Temporal vertical profiling

Modern systems are enormously complex; many applications today comprise millions of lines of code, make extensive use of software frameworks, and run on complex, multi‐tiered, run‐time systems. Understanding the performance of these applications is challenging because it depends on the interactions between the many software and the hardware components. This paper describes and evaluates an interactive and iterative methodology, temporal vertical profiling, for understanding the performance of applications. There are two key insights behind temporal vertical profiling. First, we need to collect and reason across information from multiple layers of the system before we can understand an application's performance. Second, application performance changes over time and thus we must consider the time‐varying behavior of the application instead of aggregate statistics. We have developed temporal vertical profiling from our own experience of analyzing performance anomalies and have found it very helpful for methodically exploring the space of hardware and software components. By representing an application's behavior as a set of metrics, where each metric is represented as a time series, temporal vertical profiling provides a way to reason about performance across system layers, regardless of their level of abstraction, and independent of their semantics. Temporal vertical profiling provides a methodology to explore a large space of metrics, hundreds of metrics even for small benchmarks, in a systematic way. Copyright © 2010 John Wiley & Sons, Ltd.     

An efficient mutual authentication RFID scheme based on elliptic curve cryptography

Radio frequency identification (RFID) tags have been widely deployed in many applications, such as supply chain management, inventory control, and traffic card payment. However, these applications can suffer from security issues or privacy violations when the underlying data-protection techniques are not properly designed. Hence, many secure RFID authentication protocols have been proposed. According to the resource usage of the tags, secure RFID protocols are classified into four types: full-fledged, simple, lightweight, and ultra-lightweight. In general, non-full-fledged protocols are vulnerable to desynchronization, impersonation, and tracking attacks, and they also lack scalability. If the tag resources allow more flexibility, full-fledged protocols seem to be an attractive solution. In this study, we examine full-fledged RFID authentication protocols and discuss their security issues. We then design a novel RFID authentication protocol based on elliptic curve cryptography, to avoid these issues. In addition, we present a detailed security analysis and a comparison with related studies; the results show that our scheme is more resistant to a variety of attacks and that it has the best scalability, while maintaining competitive levels of efficiency.     

基于用户行为分析的智能终端应用管理优化

随着智能终端的普及,涌现了多种多样的应用程序以满足用户需求.现有智能终端系统普遍使用基于LRU算法的Task killing机制管理后台应用程序,LRU算法只考虑了应用最近的使用情况,没有考虑用户使用习惯,可能导致后台应用程序被错误地终止,当用户切换回该应用程序时,会带来应用启动延迟增加、能耗增加、状态丢失等问题.本文设计并实现了一种基于贝叶斯网络的应用管理方法BNLP,并在Android移动终端上验证.该方法通过分析用户使用行为,预测后台应用程序即将被启动的概率,并据此进行应用管理.在LiveLab数据集上的实验表明,本文提出的BNLP模型相比于LRU算法应用程序重启率降低了17.2%,从而降低了延迟和能耗、提升了用户体验.     

Knowledge information processing language: ShapeUp

A new logic programming language, ShapeUp, is developed. ShapeUp is an expanded Prolog system with string matching facilities. The language has been developed to give programmers a new computer programming environment, especially for knowledge information processing. This area includes natural language comprehension and intelligent text processing systems with better man-machine interfaces. For this kind of application, character string data play a principal part rather than conventional numerical data. In ShapeUp, string patterns are introduced as Prolog ‘terms’. Their matching process is performed inside the unification. Thus, a program is far simpler and easier to write and read in ShapeUp, than in conventional Prolog systems, and program size is extremely reduced.     

Emerging research areas in SIP-based converged services for extended Web clients

The convergence of Next Generation Networks and Internet-based rich applications are generating relevant industrial opportunities in the market of mobility-enabled services. Even if this trend is widely recognized, there are still a few industrial-level solutions that effectively support session mobility in a transparent way and with the capability of openly integrating with existing and legacy applications. In this paper we propose a SIP-based hybrid architecture for Web session mobility that offers content sharing and session handoff between Web browsers. In addition, its technical originality includes integrating a SIP stack into a Web browser, thus offering the advantage of extending a Web browser to act as a SIP client. Lastly, a rich set of control services that prevent abuse of content sharing and session handoff are introduced into the proposed system. The implemented solution uses SIP in a standard way to migrate Web sessions between Web browsers; it is made up of a SIP integrated Web client and a converged (SIP and HTTP) Application Server that can be easily used to enable session mobility in any kind of Web-based application. In addition, the implemented system has recently evolved to a framework for developing different kinds of converged services over the Internet, analogously to what is possible with Google Wave and the existing telephony APIs. Finally, the paper reports the evaluation of the proposed framework and of the employed technologies, together with directions of future work, in terms of both extension to other application domains and exploration of research areas/models that can benefit form the adoption of SIP and Web-related solutions.     

MyBenchmark: generating databases for query workloads

To evaluate the performance of database applications and database management systems (DBMSs), we usually execute workloads of queries on generated databases of different sizes and then benchmark various measures such as respond time and throughput. This paper introduces MyBenchmark, a parallel data generation tool that takes a set of queries as input and generates database instances. Users of MyBenchmark can control the characteristics of the generated data as well as the characteristics of the resulting workload. Applications of MyBenchmark include DBMS testing, database application testing, and application-driven benchmarking. In this paper, we present the architecture and the implementation algorithms of MyBenchmark. Experimental results show that MyBenchmark is able to generate workload-aware databases for a variety of workloads including query workloads extracted from TPC-C, TPC-E, TPC-H, and TPC-W benchmarks.