Optimizing Computation of Recovery Plans for BPEL Applications

Web service applications are distributed processes that are composed of dynamically bounded services. In our previous work [15], we have described a framework for performing runtime monitoring of web service against behavioural correctness properties (described using property patterns and converted into finite state automata). These specify forbidden behavior (safety properties) and desired behavior (bounded liveness properties). Finite execution traces of web services described in BPEL are checked for conformance at runtime. When violations are discovered, our framework automatically proposes and ranks recovery plans which users can then select for execution. Such plans for safety violations essentially involve "going back" - compensating the executed actions until an alternative behaviour of the application is possible. For bounded liveness violations, recovery plans include both "going back" and "re-planning" - guiding the application towards a desired behaviour. Our experience, reported in [16], identified a drawback in this approach: we compute too many plans due to (a) overapproximating the number of program points where an alternative behaviour is possible and (b) generating recovery plans for bounded liveness properties which can potentially violate safety properties. In this paper, we describe improvements to our framework that remedy these problems and describe their effectiveness on a case study.Comment: In Proceedings TAV-WEB 2010, arXiv:1009.330

Expectile Matrix Factorization for Skewed Data Analysis

Matrix factorization is a popular approach to solving matrix estimation problems based on partial observations. Existing matrix factorization is based on least squares and aims to yield a low-rank matrix to interpret the conditional sample means given the observations. However, in many real applications with skewed and extreme data, least squares cannot explain their central tendency or tail distributions, yielding undesired estimates. In this paper, we propose \emph{expectile matrix factorization} by introducing asymmetric least squares, a key concept in expectile regression analysis, into the matrix factorization framework. We propose an efficient algorithm to solve the new problem based on alternating minimization and quadratic programming. We prove that our algorithm converges to a global optimum and exactly recovers the true underlying low-rank matrices when noise is zero. For synthetic data with skewed noise and a real-world dataset containing web service response times, the proposed scheme achieves lower recovery errors than the existing matrix factorization method based on least squares in a wide range of settings.Comment: 8 page main text with 5 page supplementary documents, published in AAAI 201

Mathematical evaluation of context transfer and multicast fast reroute in multicast enabled network mobility management

Internet applications such as web based monitoring; live internet video, online video, video conference, webcam viewing and internet video to TV are highly used in today’s IP communication. The trends of these applications are, that they are played on mobile devices and distributed to many end users. Multicast communication over IP contributes to the end users applications distribution. It has been discovered by a CISCO research that mobile multicast traffic will soon reach zetabyte in 2019. The aim of this paper is to introduce new method that enable multicast in network mobility management. The new method is using context transfer and multicast fast reroute technique. The proposed method is quantitatively evaluated in terms of packet loss and service recovery tim

Integrated Data, Message, and Process Recovery for Failure Masking in Web Services

Modern Web Services applications encompass multiple distributed interacting components, possibly including millions of lines of code written in different programming languages. With this complexity, some bugs often remain undetected despite extensive testing procedures, and occasionally cause transient system failures. Incorrect failure handling in applications often leads to incomplete or to unintentional request executions. A family of recovery protocols called interaction contracts provides a generic solution to this problem by means of system-integrated data, process, and message recovery for multi-tier applications. It is able to mask failures, and allows programmers to concentrate on the application logic, thus speeding up the development process. This thesis consists of two major parts. The first part formally specifies the interaction contracts using the state-and-activity chart language. Moreover, it presents a formal specification of a concrete Web Service that makes use of interaction contracts, and contains no other error-handling actions. The formal specifications undergo verification where crucial safety and liveness properties expressed in temporal logics are mathematically proved by means of model checking. In particular, it is shown that each end-user request is executed exactly once. The second part of the thesis demonstrates the viability of the interaction framework in a real world system. More specifically, a cascadable Web Service platform, EOS, is built based on widely used components, Microsoft Internet Explorer and PHP application server, with interaction contracts integrated into them.Heutige Web-Service-Anwendungen setzen sich aus mehreren verteilten interagierenden Komponenten zusammen. Dabei werden oft mehrere Programmiersprachen eingesetzt, und der Quellcode einer Komponente kann mehrere Millionen Programmzeilen umfassen. In Anbetracht dieser Komplexität bleiben typischerweise einige Programmierfehler trotz intensiver Qualitätssicherung unentdeckt und verursachen vorübergehende Systemsausfälle zur Laufzeit. Eine ungenügende Fehlerbehandlung in Anwendungen führt oft zur unvollständigen oder unbeabsichtigt wiederholten Ausführung einer Operation. Eine Familie von Recovery-Protokollen, die so genannten "Interaction Contracts", bietet eine generische Lösung dieses Problems. Diese Recovery- Protokolle sorgen für die Fehlermaskierung und ermöglichen somit, dass Entwickler ihre ganze Konzentration der Anwendungslogik widmen können. Dies trägt zu einer erheblichen Beschleunigung des Entwicklungsprozesses bei. Diese Dissertation besteht aus zwei wesentlichen Teilen. Der erste Teil widmet sich der formalen Spezifikation der Recovery-Protokolle unter Verwendung des Formalismus der State-and-Activity-Charts. Darüber hinaus entwickeln wir die formale Spezifikation einer Web-Service-Anwendung, die außer den Recovery-Protokollen keine weitere Fehlerbehandlung beinhaltet. Die formalen Spezifikationen werden in Bezug auf kritische Sicherheits- und Lebendigkeitseigenschaften, die als temporallogische Formeln angegeben sind, mittels "Model Checking" verifiziert. Unter anderem wird somit mathematisch bewiesen, dass jede Operation eines Endbenutzers genau einmal ausgeführt wird. Der zweite Teil der Dissertation beschreibt die Implementierung der Recovery- Protokolle im Rahmen einer beliebig verteilbaren Web-Service-Plattform EOS, die auf weit verbreiteten Web-Produkten aufbaut: dem Browser "Microsoft Internet Explorer" und dem PHP-Anwendungsserver

Implementasi Dan Evaluasi Kinerja Disaster Recovery dalam Lingkungan Data Center Berbasis Cloud - Implementation And Evaluation Of Disaster Recovery Performance In Cloud-Based Data Center Environment

Meningkatnya pertumbuhan penggunaan internet diimbangi dengan tingginya permintaan pengguna atau penikmat layanan aplikasi agar aplikasi dapat diakses setiap waktu. Di zaman milenial ini, ketersedian aplikasi menjadi raja dari segala sesuatu, jika aplikasi tidak dapat diakses bahkan dalam satu menit akan menjadi masalah besar bagi pemilik bisnis dan mengancam reputasi perusahaan terutama yang membutuhkan ketersediaan aplikasi selama 24 jam contohnya aplikasi perbankan, aplikasi e-commerse, dsb. Untuk menjamin ketersediaan aplikasi dan sistem mayoritas perusahaan yang memiliki infrastruktur tradisional atau private server memiliki disaster planning mulai dari cara paling sederhana yaitu melakukan backup secara berkala maupun membangun sistem Disaster Recovery secara realtime. Saat ini, ada banyak penyedia cloud yang menawarkan layanan yang disebut DRaaS (Disaster Recovery as a Service) untuk memfasilitasi kebutuhan perusahaan yang ingin menjaga kelangsungan bisnis mereka. Banyaknya penyedia layanan cloud serta miripnya layanan yang ditawarkan membuat calon pengguna bingung penyedia cloud mana yang sesuai dengan sistem bisnis mereka. Penelitian ini memperkenalkan metode desain implementasi DRaaS dari dua penyedia layanan cloud berbeda untuk mendapatkan parameter RPO dan RTO yang nantinya dijadikan pertimbangan dalam memilih layanan DRaaS. Hasil dari penelitian ini adalah sebuah sistem disaster recovery yang menggunakan Google Cloud dan Amazon Web Service sebagai secondary server yang menghasilkan nilai RPO 3 menit. Sistem DRaaS ini telah diuji untuk melakukan failover dengan nilai RTO 9,6 detik untuk Google Cloud dan 15,4 detik untuk Amazon Web Service. ========================================================================================================== The increasing growth of Internet use is offset by the high demand of users or connoisseurs of application services for applications to be accessed at any time. In this millennial era, the availability of applications to be the king of everything, if the application can not be accessed even within a minute will be a big problem for business owners and threaten the reputation of the company especially those requiring 24 hours application availability for example banking applications, e-commerce applications, etc. To ensure the availability of applications and systems the majority of companies that have a traditional infrastructure or private server has a disaster planning starting from the simplest way of doing regular backups and build system Disaster Recovery in realtime. Currently, there are many cloud providers offering services called DRaaS (Disaster Recovery as a Service) to facilitate the needs of companies that want to keep their business going. The number of cloud service providers and similar services offered to make prospective users confused which cloud provider that suits their business systems. This research introduces the design method of DRaaS implementation from two different cloud service providers to get RPO and RTO parameters which will be taken into consideration in choosing DRaaS service. The results of this study is a disaster recovery system that uses Google Cloud and Amazon Web Service as a secondary server that produces a 3 minute RPO value. This DRaaS system has been tested for failover with RTO value 9.6 seconds for Google Cloud and 15.4 seconds for Amazon Web Service

Towards an Enhanced Protocol for Improving Transactional Support in Interoperable Service Oriented Application-Based (SOA-Based) Systems

When using a shared database for distributed transactions, it is often difficult to connect business processes and softwarecomponents running on disparate platforms into a single transaction. For instance, one platform may add or update data, and thenanother platform later access the changed or added data. This severely limits transactional capabilities across platforms. Thissituation becomes more acute when concurrent transactions with interleaving operations spans across different applications andresources. Addressing this problem in an open, dynamic and distributed environment of web services poses special challenges,and still remains an open issue. Following the broad adoption and use of the standard Web Services Transaction Protocols,requirements have grown for the addition of extended protocols to handle problems that exist within the context of interoperableservice-oriented applications. Most extensions to the current standard WS-Transaction Protocols still lack proper mechanisms forerror-handling, concurrency control, transaction recovery, consolidation of multiple transaction calls into a single call, and securereporting and tracing for suspicious activities. In this research, we will first extend the current standard WS-TransactionFramework, and then propose an enhanced protocol (that can be deployed within the extended framework) to improvetransactional and security support for asynchronous applications in a distributed environment. A hybrid methodology whichincorporates service-oriented engineering and rapid application development will be used to develop a procurement system(which represents an interoperable service-oriented application) that integrates our proposed protocol. We will empiricallyevaluate and compare the performance of the enhanced protocol with other conventional distributed protocols (such as 2PL) interms of QoS parameters (throughput, response time, and resource utilization), availability of the application, databaseconsistency, and effect of locking on latency, among other factors.Keywords: Database, interoperability, security, concurrent transaction, web services, protocol, service-oriente

Data Security on Backed Up Data and Recovery in Cloud Storage

Cloud provides its users with different services. Every day during cloud computing, a great deal of data is generated. On the cloud servers, the data is being saved. A recovery tool should be created in case this data is lost from the server. One such setup is described in this consideration. The proposed approach would enable simultaneous data storage on the inaccessible server and the cloud server. The information is returned from the farther server when the key record is misplaced. Secret key security is ensured so that the authentication is secure and authorized by the user based on the attributes of backup and recovery. A cloud is a distinct Information Technology infrastructure designed to provide its users with different facilities that can be gotten to remotely. Cloud alludes to the term arrange of systems that back get to decentralized Data Innovation assets. Cloud employments the Web as well as the inaccessible central servers to manage consumers and businessmen's data and applications. This helps to save the consumer from costs and room problems. It is a technology that makes data collection, processing, and bandwidth much more centralized. A cloud encompasses a certain restrain, because it could be a certain system utilized to supply assets remotely. The Web offers get to an endless number of clouds. Though the Web offers free get to a few web-based Information Technology services, a cloud is generally private and provides wireless data resources. Much of the Internet is accessible via the web service to Information Technology services. On the other hand, the Information Technology services supplied by cloud environments are intended to provide back-end computing capabilities and browser access.

Supporting Young People With Psychosis In The Community: An ICT Enabled Relapse Prevention Tool

Psychotic disorders are the most disabling of all mental illnesses and place a heavy demand on limited mental health services. Consequently, this research aims to develop novel approaches to care which are less demanding of public resources. This research-in-progress is based in an innovative youth mental health service in Australia. It presents a model for a web-based platform which provides support for relapse prevention in young people with first-episode psychosis (FEP). This study combines Information Systems and Psychology theory and research to develop an advanced web-based interactive psychosocial intervention for relapse prevention and recovery in FEP. While web-based applications to support schizophrenia, depression and anxiety have been researched such approaches have not been applied to the problem of relapse prevention in young people with FEP. The research uses focus groups to study case managers, clients of the support organisation and usability experts to inform an initial prototype which has then been presented to a group of clients for evaluation. It concludes that an intervention based on intelligent technologies which combine social networking and web-based treatment to promote independent home based care would best suit the characteristics of the target group and should be tested in large-scale in the community

Investigation into Mobile Learning Framework in Cloud Computing Platform

Abstract—Cloud computing infrastructure is increasingly used for distributed applications. Mobile learning applications deployed in the cloud are a new research direction. The applications require specific development approaches for effective and reliable communication. This paper proposes an interdisciplinary approach for design and development of mobile applications in the cloud. The approach includes front service toolkit and backend service toolkit. The front service toolkit packages data and sends it to a backend deployed in a cloud computing platform. The backend service toolkit manages rules and workflow, and then transmits required results to the front service toolkit. To further show feasibility of the approach, the paper introduces a case study and shows its performance