MobiThin management framework: design and evaluation

In thin client computing, applications are executed on centralized servers. User input (e.g. keystrokes) is sent to a remote server which processes the event and sends the audiovisual output back to the client. This enables execution of complex applications from thin devices. Adopting virtualization technologies on the thin client server brings several advantages, e.g. dedicated environments for each user and interesting facilities such as migration tools. In this paper, a mobile thin client service offered to a large number of mobile users is designed. Pervasive mobile thin client computing requires an intelligent service management to guarantee a high user experience. Due to the dynamic environment, the service management framework has to monitor the environment and intervene when necessary (e.g. adapt thin client protocol settings, move a session from one server to another). A detailed performance analysis of the implemented prototype is presented. It is shown that the prototype can handle up to 700 requests/s to start the mobile thin client service. The prototype can make a decision for up to 700 monitor reports per second

Service-oriented mobility of java code in web services-based architectures

Dissertação apresentada na Faculdade de Ciências e Tecnologias da Universidade Nova de Lisboa para a obtenção do Grau de Mestre em Engenharia InformáticaSoftware mobility consists of providing software components, the ability to migrate to a remote host with the purpose of interacting locally. In other words, this technology enables computations to be transferred from the current machine to a remote one. This powerful enhancement embodied in a traditional network fairly raises security concerns. For now, we believe that software mobility paradigm is confined to environments with bases of trust such as local area networks or middleware layers where security issues can be better controlled. Service-oriented computations reorganize the network architecture in the form of services, where components are more easily integrated, modified and removed. They have the ability to cooperate between them regardless the programming language used in their development. In addition, service-oriented computing is a widely accepted technology for the implementation of distributed applications, namely middleware. The work developed in this thesis consists of instantiating a model which combines software mobility and service-oriented paradigms as proposed by Paulino [20]. In this model, migrating sessions take advantage of the resources of a service-oriented network, creating thus an environment where the migration is modeled in terms of services instead of network nodes abstractions. In the instantiated model, we aim to apply the migration of Java programs in a context of a service-oriented architecture developed with Web services. This application comprises of a middleware layer that runs between the source program and the Web services technologies, and whose interface is the result of the mapping of the operations defined in the model. The evaluation performed to the instantiated model allows us to identify situations in which component migration to the server to interact locally is more advantageous in comparison to remote interacting with it

MobiDesk: Mobile Virtual Desktop Computing

We present MobiDesk, a mobile virtual desktop computing hosting infrastructure that leverages continued improvements in network speed, cost, and ubiquity to address the complexity, cost, and mobility limitations of today's personal computing infrastructure. MobiDesk transparently virtualizes a user's computing session by abstracting underlying system resources in three key areas: display, operating system and network. MobiDesk provides a thin virtualization layer that decouples a user's computing session from any particular end user device and moves all application logic from end user devices to hosting providers. MobiDesk virtualization decouples a user's computing session from the underlying operating system and server instance, enabling high availability service by transparently migrating sessions from one server to another during server maintenance or upgrades. We have implemented a MobiDesk prototype in Linux that works with existing unmodified applications and operating system kernels. Our experimental results demonstrate that MobiDesk has very low virtualization overhead, can provide a full-featured desktop experience including full-motion video support, and is able to migrate users' sessions efficiently and reliably for high availability, while maintaining existing network connections

Split and Migrate: Resource-Driven Placement and Discovery of Microservices at the Edge

Microservices architectures combine the use of fine-grained and independently-scalable services with lightweight communication protocols, such as REST calls over HTTP. Microservices bring flexibility to the development and deployment of application back-ends in the cloud. Applications such as collaborative editing tools require frequent interactions between the front-end running on users\u27 machines and a back-end formed of multiple microservices. User-perceived latencies depend on their connection to microservices, but also on the interaction patterns between these services and their databases. Placing services at the edge of the network, closer to the users, is necessary to reduce user-perceived latencies. It is however difficult to decide on the placement of complete stateful microservices at one specific core or edge location without trading between a latency reduction for some users and a latency increase for the others. We present how to dynamically deploy microservices on a combination of core and edge resources to systematically reduce user-perceived latencies. Our approach enables the split of stateful microservices, and the placement of the resulting splits on appropriate core and edge sites. Koala, a decentralized and resource-driven service discovery middleware, enables REST calls to reach and use the appropriate split, with only minimal changes to a legacy microservices application. Locality awareness using network coordinates further enables to automatically migrate services split and follow the location of the users. We confirm the effectiveness of our approach with a full prototype and an application to ShareLatex, a microservices-based collaborative editing application

Web API Fragility: How Robust is Your Web API Client

Web APIs provide a systematic and extensible approach for application-to-application interaction. A large number of mobile applications makes use of web APIs to integrate services into apps. Each Web API's evolution pace is determined by their respective developer and mobile application developers are forced to accompany the API providers in their software evolution tasks. In this paper we investigate whether mobile application developers understand and how they deal with the added distress of web APIs evolving. In particular, we studied how robust 48 high profile mobile applications are when dealing with mutated web API responses. Additionally, we interviewed three mobile application developers to better understand their choices and trade-offs regarding web API integration.Comment: Technical repor

ES6 자바스크립트의 스냅샷 기반 마이그레이션

학위논문(석사) -- 서울대학교대학원 : 공과대학 전기·정보공학부, 2021.8. 문수묵.최근 웹 플랫폼 및 자바스크립트의 인기와 함께, 자바스크립트로 작성된 프로그램을 위한 앱 마이그레이션 기술이 연구된 바 있다. 이는 이종의 기기 간에 연속적인 워크플로우를 제공해 새로운 사용자 경험을 제공하는 기술을 일컫는다. 여러 선행 연구에서 스냅샷 기반 방법론을 사용해 앱의 런타임 상태를 텍스트 형태로 직렬화 및 복원하는 시도를 했다. 그러나, 기존 연구들은 구 버전 자바스크립트 상에서 진행됐다는 한계가 있다. 이에 비해 ECMAScript2015 (ES6) 업데이트 이후 자바스크립트에 다양한 기능이 도입되었기 때문에, 기존 방법들은 오늘날 real-world 애플리케이션을 마이그레이션하기 어렵다. 본 논문은 [19]에서 소개된 우리의 프레임워크를 소개한다. 우리는 선행 연구에서 다뤄지지 않은 block scope, module, class syntax와 같은 ES6의 주요 기능을 분석했으며 이러한 새로운 기능을 사용하는 앱을 마이그레이션 하기 위한 알고리즘을 제안했다. 또한, 우리는 최신 자바스크립트 엔진에 대한 분석을 통해 실행 중인 자바스크립트 프로그램의 런타임 상태를 scope tree라는 자료구조 상에 직렬화하고, 후처리를 거친 scope tree로부터 스냅샷 코드를 생성했다. 이러한 방법론을 V8 자바스크립트 엔진인 상에 구현했으며, 복잡한 최신 자바스크립트 기능을 사용하는 벤치마크 프로그램에 대해 실험했다. 실험 결과를 통해 이러한 방법이 모바일 기기 간에 5개의 벤치마크 프로그램을 성공적으로 마이그레이션 시킨다는 것을 보였다. 복잡도가 가장 높은 앱 (ML 벤치마크, 소스 코드 크기 213KB)에 대한 실험에서 프레임워크로 인한 시간 부하를 측정한 결과, X86 랩톱에서 200ms 미만, ARM 기반 임베디드 보드에서 800ms 미만이었다. 이러한 결과를 통해 자원이 제한된 IoT 기기 등에 대한 적용 가능성을 검증했으며, 추가적으로 프레임워크의 활용 방안 및 향후 연구 방향에 대해 논의한다.With the growing popularity of the web platform and JavaScript, an interesting user experience called application (app) migration has been proposed for JavaScript programs. To enable a non-breaking workflow across different devices, recent studies have proposed snapshot-based techniques in which an app’s runtime state is serialized into a text form that can be restored back later. A limitation of existing literature, however, is that they are based on old JavaScript specifications. Since major updates introduced by ECMASCript2015 (a.k.a. ES6), JavaScript supports various features that cannot be migrated correctly with existing methods. Some of these features are heavily used in today’s real-world apps and thus greatly reduces the scope of previous works. In this thesis, I will mainly introduce my work presented in [19]. In the paper, we analyzed ES6 features such as block scopes, modules, and class syntax that were previously uncovered in app migration. We presented an algorithm that enables migration of apps implemented with these new features. Based on the standards adopted in modern JavaScript engines, our approach serializes a running program into a scope tree and reorganizes it for snapshot code generation. We implemented our idea on the open source V8 engine and experiment with complex benchmark programs of modern JavaScript. Results showed that our approach correctly migrates 5 target programs between mobile devices. Our framework could migrate the most complex app of source code size 213KB in less than 200ms in a X86 laptop and 800ms in an embedded ARM board, showing feasibility in resource-constrained IoT devices. I will also discuss possible use cases and research directions and conclude.Chapter 1. Introduction 1 1.1. JavaScript App Migration 1 1.2. Purpose of Research 2 Chapter 2. Background 4 2.1. Snapshot-based Approach 4 2.2. Function Closure and Scope Tree 6 2.3. Limitations of Previous Works 6 Chapter 3. Proposed Approach 10 3.1. Module Profiling 10 3.2. Migrating Modified Built-in Objects 11 3.3. Scope Tree Building 11 3.4. Syntax-Aware Tree Re-ordering 12 3.5. Tree Partitioning 13 3.6. Snapshot Code Generation 13 Chapter 4. Evaluation 17 4.1. Implementation and Setup 17 4.2. Scope Tree Analysis 18 4.3. Snapshot Code Sizes 19 4.4. Framework Time Overhead 20 Chapter 5. Discussion 22 5.1. Limitations 22 5.2. Alternative Approach 22 5.3. Potential Use Cases 23 Chapter 6. Conclusion 24 Bibliography 25 Abstract in Korean 27석