73 research outputs found

    An Approach of Integrating Communication Services in Applications for Android-Based Digital TV Receivers

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    Digital TV receivers are becoming increasingly powerful devices allowing consumers to not only watch television broadcasts but also to access the Internet or communicate to other devices in the same local area network through either an Ethernet connection or by using a wireless connection. As the living room represents a meeting place for family and friends to gather and socialize in, the possibility of playing informal games using the television set as the interaction device is very attractive. This paper presents a developed application that integrates new communication capabilities of digital TV receivers running the Android OS. The application is a game showing its content overlaid on top of a television program whereas Android mobile devices are used as controllers. The performance of the application is tested by measuring the response times of the various communication services and by analyzing feedback from a selected group of users

    IoT Application Provisioning Service

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    Constant development of software requires updating our Internet of Things (IoT) devices regularly. Some services such as transportation, health care, surveillance and electronic payments require high availability, even during a software update. IoT updates in urban scenarios require connectivity based on the Internet Protocol (IP) and long range connection with adequate speed. Normally, these requirements are provided by cellular network (i.e., using a SIM card) to connect to the Internet. This option presents several disadvantages: it is very expensive and it exposes IoT devices to security threats due to the permanent connection to the Internet. These challenges could be addressed by leveraging long-range broadcast communication (e.g., FM broadcast). IoT devices periodically listen for and receive updates through such a communication infrastructure, without actually being connected to the Internet. This thesis presents a system to provide software updates for IoT devices through long-range broadcast communication technologies. A prototype has been developed based on the concept of ā€œseamless updatesā€. This allows performing software updates in the background, hence ensuring the availability of a device during the installation time of an update. This seamless update process was implemented on an embedded device (i.e., a Raspberry Pi 3) with a Linux-based operating system. Furthermore, a web-based backend has been implemented. Such a backend allows IoT developers to upload their updates targeting a specific class of devices and schedule when the update will be sent. The security goals of integrity and authentication are accomplished by signing the updates in the backend and verifying it at the IoT device. Moreover, a performance evaluation is performed for the system upgrade service with different parameters to sign the updates

    ė‚“ģž„ķ˜• ģ‹œģŠ¤ķ…œģ—ģ„œ Just-in-Time ė° Ahead-of-Time ģ»“ķŒŒģ¼ģ„ ķ™œģš©ķ•œ ķ•˜ģ“ėøŒė¦¬ė“œ ģžė°” ģ»“ķŒŒģ¼

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    ķ•™ģœ„ė…¼ė¬ø (ė°•ģ‚¬)-- ģ„œģšøėŒ€ķ•™źµ ėŒ€ķ•™ģ› : ģ „źø°Ā·ģ»“ķ“Øķ„°ź³µķ•™ė¶€, 2015. 8. ė¬øģˆ˜ė¬µ.Many embedded Java software platforms execute two types of Java classes: those installed statically on the client device and those downloaded dynamically from service providers at runtime. For higher performance, it would be desirable to compile static Java classes by ahead-of-time compiler (AOTC) and to handle dynamically downloaded classes by just-in-time compiler (JITC), providing a hybrid compilation environment. We propose a hybrid Java compilation approach and performs an initial case study with a hybrid environment, which is constructed simply by merging an existing AOTC and a JITC for the same JVM. Contrary to our expectations, the hybrid environment does not deliver a performance, in-between of full-JITCs and full-AOTCs. In fact, its performance is even lower than full-JITCs for many benchmarks. We analyzed the result and found that a naive merge of JITC and AOTC may result in inefficiencies, especially due to calls between JITC methods and AOTC methods. We also observed that the distribution of JITC methods and AOTC methods is also important, and experimented with various distributions to understand when a hybrid environment can deliver a desired performance. The Android Java is to be executed by the Dalvik virtual machine (VM), which is quite different from the traditional Java VM such as Oracles HotSpot VM. That is, Dalvik employs register-based bytecode while HotSpot employs stack-based bytecode, requiring a different way of interpretation. Also, Dalvik uses trace-based just-in-time compilation (JITC), while HotSpot uses method-based JITC. Therefore, it is questioned how the Dalvik VM performs compared the HotSpot VM. Unfortunately, there has been little comparative evaluation of both VMs, so the performance of the Dalvik VM is not well understood. More importantly, it is also not well understood how the performance of the Dalvik VM affects the overall performance of the Android applications (apps). We make an attempt to evaluate the Dalvik VM. We install both VMs on the same board and compare the performance using EEMBC benchmark. In the JITC mode, Dakvik is slower than HotSpot by more than 2.9 times and its generated code size is not smaller than HotSpots due to its worse code quality and trace-chaining code. We also investigated how real Android apps are different from Java benchmarks, to understand why the slow Dalvik VM does not affect the performance of the Android apps seriously. We proposes a bytecode-to-C ahead-of-time compilation (AOTC) for the DVM to accelerate pre-installed apps. We translated the bytecode of some of the hot methods used by these apps to C code, which is then compiled together with the DVM source code. AOTC-generated code works with the existing Android zygote mechanism, with correct garbage collection and exception handling. Due to off-line, method-based compilation using existing compiler with full optimizations and Java-specific optimizations, AOTC can generate quality code while obviating runtime compilation overhead. For benchmarks, AOTC can improve the performance by 65%. When we compare with the recently-introduced ART, which also performs ahead-of-time compilation, our AOTC performs better. We cannot AOTC all middleware and framework methods in DTV and android device for hybrid compilation. By case study on DTV, we found that we need to adopt AOTC enough methods and reduce method call overhead. We propose AOTC method selection heuristic using method call chain. We select hot methods and call chain methods using profile data. Our heuristic based on method call chain get better performance than other heuristics.Chapter 1 Introduction 1 1.1 The need of hybrid compilation 1 1.2 Outline of the Dissertation 2 Chapter 2 Hybrid Compilation for Java Virtual Machine 3 2.1 The Approach of Hybrid Compilation 3 2.2 The JITC and AOTC 6 2.2.1 JVM and the Interpreter 7 2.2.2 The JITC 8 2.2.3 The AOTC 9 2.3 Hybrid Compilation Environment 11 2.4 Analysis of the Hybrid Environment 14 2.4.1 Call Behavior of Benchmarks 14 2.4.2 Call Overhead 15 2.4.3 Application Methods and Library Methods 18 2.4.4 Improving hybrid performance 20 2.4.4.1 Reducing the JITC-to-AOTC call overhead 20 2.4.4.2 Performance impact of the distribution of JITC methods and AOTC methods 21 Chapter 3 Evaluation of Dalvik Virtual Machine 23 3.1 Android Platform 23 3.2 Java VM and Dalvik VM 24 3.2.1 Bytecode ISA 25 3.2.3 Just-in-Time Compilation (JITC) 27 3.3 Experimental Results 32 3.3.1 Experimental Environment 33 3.3.2 Interpreter Performance 34 3.3.3 JITC Performance 37 3.3.4 Trace Extension 43 3.4 Behavior of Real Android Apps 44 Chapter 4 Ahead-of-Time Compilation for Dalvik Virtual Machine 51 4.1 Android and Dalvik VM Execution 51 4.1.1 Android Execution Model 51 4.1.2 Dalvik VM 51 4.1.3 Dexopt and JITC in the Dalvik VM 53 4.2 AOTC Architecture 54 4.3 Design and Implementation of AOTC 56 4.3.1 Dexopt and Code Generation 56 4.3.2 C Code Generation 56 4.3.3 AOTC Method Call 58 4.3.4 Garbage Collection 61 4.3.5 Exception Handling 62 4.3.6 AOTC Method Linking 63 4.4 AOTC Code Optimization 64 4.4.1 Method Inlining 64 4.4.2 Spill Optimization 64 4.4.3 Elimination of Redundant Code 65 4.5 Experimental Result 65 4.5.1 Experimental Environment 66 4.5.2 AOTC Target Methods 66 4.5.3 Performance Impact of AOTC 67 4.5.4 DVM AOTC vs. ART 68 Chapter 5 Selecting Ahead-of-Time Compilation Target Methods for Hybrid Compilation 70 5.1 Hybrid Compilation on DTV 70 5.2 Hybrid Compilation on Android Device 72 5.3 AOTC for Hybrid Compilation 74 5.3.1 AOTC Target Methods 74 5.3.2 Case Study: Selecting on DTV 75 5.4 Method Selection Using Call Chain 77 5.5 Experimental Result 77 5.5.1 Experimental Environment 78 5.5.2 Performance Impact 79 Chapter 6 Related Works 81 Chapter 7 Conclusion 84 Bibliography 86Docto

    Mobile Web applications

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    This document presents the work that was elaborated at the company Present Technologies as part of the academic discipline Internship/Industrial Project for the Masterā€™s degree in Informatics and Systems, Software Development branch, at Instituto Superior de Engenharia de Coimbra. The area of the mobile web applications has grown exponentially over the last few years turning it into a very dynamic field where new development platforms and frameworks are constantly emerging. Thus, the internship consisted in the study of two new mobile operating systems, Tizen and Firefox OS, as well as two frameworks for packaging of mobile web applications ā€“ Adobe PhoneGap and Appcelerator Titanium. These platforms are in the direct interest of Present Technology since it pretends to use them in its future projects in general and in the Phune Gaming project in particular. Since Television is one of the Present Technologiesā€™ business areas, during the course of the internship it was decided to perform additionally a study of two Smart TV platforms, namely Samsung Smart TV and Opera TV, which was considered as a valuable knowledge for the company. For each of the platforms was performed a study about its architecture, supported standards and the development tools that are provided, nevertheless the focus was on the applications and for this reason a practical case study was conducted. The case studies consisted in the creation of a prototype or packaging of an application, for the case of the packaging tools, in order to prove the feasibility of the applications for the Present Technologiesā€™ needs. The outcome of the work performed during the internship is that it raised the awareness of Present Technology of the studied platforms, providing it with prototypes and written documentation for the platformsā€™ successful usage in future projects

    Mobile Web applications

    Get PDF
    This document presents the work that was elaborated at the company Present Technologies as part of the academic discipline Internship/Industrial Project for the Masterā€™s degree in Informatics and Systems, Software Development branch, at Instituto Superior de Engenharia de Coimbra. The area of the mobile web applications has grown exponentially over the last few years turning it into a very dynamic field where new development platforms and frameworks are constantly emerging. Thus, the internship consisted in the study of two new mobile operating systems, Tizen and Firefox OS, as well as two frameworks for packaging of mobile web applications ā€“ Adobe PhoneGap and Appcelerator Titanium. These platforms are in the direct interest of Present Technology since it pretends to use them in its future projects in general and in the Phune Gaming project in particular. Since Television is one of the Present Technologiesā€™ business areas, during the course of the internship it was decided to perform additionally a study of two Smart TV platforms, namely Samsung Smart TV and Opera TV, which was considered as a valuable knowledge for the company. For each of the platforms was performed a study about its architecture, supported standards and the development tools that are provided, nevertheless the focus was on the applications and for this reason a practical case study was conducted. The case studies consisted in the creation of a prototype or packaging of an application, for the case of the packaging tools, in order to prove the feasibility of the applications for the Present Technologiesā€™ needs. The outcome of the work performed during the internship is that it raised the awareness of Present Technology of the studied platforms, providing it with prototypes and written documentation for the platformsā€™ successful usage in future projects

    User Interface Abstraction for enabling TV set based Inclusive Access to the Information Society

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    199 p.The television (TV) set is present in most homes worldwide, and is the most used Information and Communication Technology (ICT). Despite its large implantation in the market, the interactive services consumption on TV set is limited. This thesis focuses on overcoming the following limiting factors: (i) limited Human Computer Interaction and (ii) lack of considering userā€™s real life context in the digital television (dTV) service integration strategy. Making interactive services accessible to TV setā€™s large user base, and especially to the most vulnerable ones, is understood as the path to integrate the mankind with the information society. This thesis explores the use of user interface abstraction technologies to reach the introduced goals. The main contributions of this thesis are: (i) an approach to enable the universally accessible remote control of the TV set, (ii) an approach for the provision of universally accessible interactive services through TV sets, and (iii) an approach for the provision of universally accessible services in the TV userā€™s real life context. We have implemented the contributing approaches for different use cases, and we have evaluated them with real users, achieving good results

    Semi-automated mobile television interactive application generation based on XHTML and Java ME

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    Mobile Digital TV (MDTV), the hybrid of Digital Television (DTV) and mobile devices (such as mobile phones), has introduced a new way for people to watch DTV and has brought new opportunities for development in the DTV industry. Nowadays, the development of the next generation MDTV service has progressed in terms of both hardware layers and software, with interactive services/applications becoming one of the future MDTV service trends. However, current MDTV interactive services still lack in terms of attracting the consumers and the service creation and implementation process relies too much on commercial solutions, resulting in most parts of the process being proprietary. In addition, this has increased the technical demands for developers as well as has increased substantially the cost of producing and maintaining MDTV services. In light of the aforementioned situation, the Thesis has contributed to this field, by proposing an innovative MDTV service creation and consumption system based on XHTML and Java ME. On the head-end it introduces a semi-automatic creation mechanism to facilitate a less technical and more efficient interactive service creation process. This enables designers and creative individuals to be actively involved in the MDTV service creation process and to develop interactive-rich MDTV service. On the client-end it employs an open-source software environment as the interactive service MDTV consumption platform, rendering the MDTV service implementation process as less proprietary as possible. Furthermore, the Thesis offers a discussion on the different MDTV interactive application models currently used and based on the proposed software, a novel MDTV service presentation method is further introduced and adopted instead of the Rich Media and ECMAScript based methods. Finally, a series of qualitative testing procedures have been implemented with regards to conducting an essential evaluation on the operability of the proposed software system.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

    Semi-automated mobile television interactive application generation based on XHTML and Java ME

    Get PDF
    Mobile Digital TV (MDTV), the hybrid of Digital Television (DTV) and mobile devices (such as mobile phones), has introduced a new way for people to watch DTV and has brought new opportunities for development in the DTV industry. Nowadays, the development of the next generation MDTV service has progressed in terms of both hardware layers and software, with interactive services/applications becoming one of the future MDTV service trends. However, current MDTV interactive services still lack in terms of attracting the consumers and the service creation and implementation process relies too much on commercial solutions, resulting in most parts of the process being proprietary. In addition, this has increased the technical demands for developers as well as has increased substantially the cost of producing and maintaining MDTV services. In light of the aforementioned situation, the Thesis has contributed to this field, by proposing an innovative MDTV service creation and consumption system based on XHTML and Java ME. On the head-end it introduces a semi-automatic creation mechanism to facilitate a less technical and more efficient interactive service creation process. This enables designers and creative individuals to be actively involved in the MDTV service creation process and to develop interactive-rich MDTV service. On the client-end it employs an open-source software environment as the interactive service MDTV consumption platform, rendering the MDTV service implementation process as less proprietary as possible. Furthermore, the Thesis offers a discussion on the different MDTV interactive application models currently used and based on the proposed software, a novel MDTV service presentation method is further introduced and adopted instead of the Rich Media and ECMAScript based methods. Finally, a series of qualitative testing procedures have been implemented with regards to conducting an essential evaluation on the operability of the proposed software system.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

    Optimal Framework for Level Based Access Control for VM Auditing on Cloud

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    The growth in the cloud computing have motivated and enable lot of application developer to deploy the applications on cloud. The major challenge of hosting on cloud is the service provider or the application provider must comply to a good number of rules. These compliance reports are time to time validated and checked by external auditors. The auditing process for the cloud services are critical and the access controls must be enabled. Due to the higher complexity and less flexibility of the virtual machines, most of the cases this access control mechanism is compromised. This work proposes four algorithms to identify and enhance the LBAC mechanism for cloud services with access updates based on time variant characteristics analysis and predictive analysis with selective cryptographic methods. The proposed model produces significantly improved results to overcome three major issues in the cloud service management as selective LBAC, static privileges and open access control for the auditors.  &nbsp
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