Asynchronous Leasing

Leasing is a very effective way to improve the performance of distributed algorithms without hampering their fault-tolerance. The notion of lease has traditionally been defined using a global notion of time and was hence strongly tied to synchronous system models. This paper introduces a new notion of lease devised for an asynchronous system model. We give the precise properties of our lease abstraction, we show how it can be implemented in an asynchronous system model, and we then illustrate its use by significantly improving the performance of a consensus-based atomic broadcast algorithm

Integrasi Business to Business untuk Proses Leasing pada Perusahaan Kredit Kendaraan Menggunakan Enterprise Service Bus

PT Astra International Tbk merupakan perusahaan yang bergerak pada perdagangan umum, perindustrian, pertambangan, pengangkutan, pertanian, pembangunan serta jasa dan konsultasi. PT Astra International Tbk memliki website Auto2000.co.id untuk melakukan layanan leasing. Auto2000.co.id diharapkan dapat terhubung ke penyedia layanan leasing yaitu PT Toyota Astra Financial Services (TAFS) dan PT Astra Credit Companies (ACC) dengan waktu tunggu respons yang minimal dan terpusat. Untuk mengatasi kebutuhan tersebut maka dibangunlah sistem integrasi B2BLeasing agar dapat mampu mengintegrasikan website Auto2000.co.id menggunakan arsitektur Enterprise Service Bus. Sistem integrasi ini dibangun menggunakan IBM Integration Bus. Sistem integrasi B2BLeasing dibangun secara Asynchronous dan Centralized Logging, agar memiliki kinerja waktu pengolahan request yang baik, meminimalkan kehilangan data, serta mencatat proses pengolahan data secara terpusat. Sistem integrasi B2Bleasing secara Asynchronous memiliki kinerja lebih baik dengan pengolahan respon sebesar 4,22 detik/request dan tanpa terjadi error daripada secara Synchronous yaitu sebesar 31,495 detik/request dengan rata-rata error 49,83%.Kata Kunci : Sistem Integrasi, Asynchronous, Centralized Logging, Enterprise Service Bus, Leasin

Context-aware Authorization in Highly Dynamic Environments

Highly dynamic computing environments, like ubiquitous and pervasive computing environments, require frequent adaptation of applications. Context is a key to adapt suiting user needs. On the other hand, standard access control trusts users once they have authenticated, despite the fact that they may reach unauthorized contexts. We analyse how taking into account dynamic information like context in the authorization subsystem can improve security, and how this new access control applies to interaction patterns, like messaging or eventing. We experiment and validate our approach using context as an authorization factor for eventing in Web service for device (like UPnP or DPWS), in smart home security

Distributed execution of bigraphical reactive systems

The bigraph embedding problem is crucial for many results and tools about bigraphs and bigraphical reactive systems (BRS). Current algorithms for computing bigraphical embeddings are centralized, i.e. designed to run locally with a complete view of the guest and host bigraphs. In order to deal with large bigraphs, and to parallelize reactions, we present a decentralized algorithm, which distributes both state and computation over several concurrent processes. This allows for distributed, parallel simulations where non-interfering reactions can be carried out concurrently; nevertheless, even in the worst case the complexity of this distributed algorithm is no worse than that of a centralized algorithm

DIAMOnDS - DIstributed Agents for MObile & Dynamic Services

Distributed Services Architecture with support for mobile agents between services, offer significantly improved communication and computational flexibility. The uses of agents allow execution of complex operations that involve large amounts of data to be processed effectively using distributed resources. The prototype system Distributed Agents for Mobile and Dynamic Services (DIAMOnDS), allows a service to send agents on its behalf, to other services, to perform data manipulation and processing. Agents have been implemented as mobile services that are discovered using the Jini Lookup mechanism and used by other services for task management and communication. Agents provide proxies for interaction with other services as well as specific GUI to monitor and control the agent activity. Thus agents acting on behalf of one service cooperate with other services to carry out a job, providing inter-operation of loosely coupled services in a semi-autonomous way. Remote file system access functionality has been incorporated by the agent framework and allows services to dynamically share and browse the file system resources of hosts, running the services. Generic database access functionality has been implemented in the mobile agent framework that allows performing complex data mining and processing operations efficiently in distributed system. A basic data searching agent is also implemented that performs a query based search in a file system. The testing of the framework was carried out on WAN by moving Connectivity Test agents between AgentStations in CERN, Switzerland and NUST, Pakistan.Comment: 7 pages, 4 figures, CHEP03, La Jolla, California, March 24-28, 200

Extending Eventually Consistent Cloud Databases for Enforcing Numeric Invariants

Geo-replicated databases often operate under the principle of eventual consistency to offer high-availability with low latency on a simple key/value store abstraction. Recently, some have adopted commutative data types to provide seamless reconciliation for special purpose data types, such as counters. Despite this, the inability to enforce numeric invariants across all replicas still remains a key shortcoming of relying on the limited guarantees of eventual consistency storage. We present a new replicated data type, called bounded counter, which adds support for numeric invariants to eventually consistent geo-replicated databases. We describe how this can be implemented on top of existing cloud stores without modifying them, using Riak as an example. Our approach adapts ideas from escrow transactions to devise a solution that is decentralized, fault-tolerant and fast. Our evaluation shows much lower latency and better scalability than the traditional approach of using strong consistency to enforce numeric invariants, thus alleviating the tension between consistency and availability

Making Space for Stories: Ambiguity in the Design of Personal Communication Systems

Pervasive personal communication technologies offer the potential for important social benefits for individual users, but also the potential for significant social difficulties and costs. In research on face-to-face social interaction, ambiguity is often identified as an important resource for resolving social difficulties. In this paper, we discuss two design cases of personal communication systems, one based on fieldwork of a commercial system and another based on an unrealized design concept. The cases illustrate how user behavior concerning a particular social difficulty, unexplained unresponsiveness, can be influenced by technological issues that result in interactional ambiguity. The cases also highlight the need to balance the utility of ambiguity against the utility of usability and communicative clarity.Comment: 10 page