Félix Cuadrado

Mobile application stores: success factors, existing approaches, and future developments

The mobile user experience has been significantly altered with the arrival of mobile broadband widespread deployments, massive improvements in available smartphones, and a shift in user habits toward a more participative, communicative role. In this context, mobile application stores have revolutionized software and content delivery. These stores focus on the applications, building around them an ecosystem of developers and consumers. The store greatly lessens the barrier between these agents, providing significant benefits to both developers and consumers. In this article we analyze this phenomenon, describing its originating factors and fundamental characteristics. We also perform a more detailed study on the two most successful application stores, identifying different approaches to implementing the model.

A Case Study on Software Evolution towards Service-Oriented Architecture

The evolution of any software product over its lifetime is unavoidable, caused both by bugs to be fixed and by new requirements appearing in the later stages of the products lifecycle. Traditional development and architecture paradigms have proven to be not suited for these continual changes, resulting in large maintenance costs. This has caused the rise of approaches such as Service Oriented Architectures (SOA), based on loosely coupled, interoperable services, aiming to address these issues. This paper describes a case study of the evolution of an existing legacy system towards a more maintainable SOA. The proposed process includes the recovery of the legacy system architecture, as a first step to define the specific evolution plan to be executed and validated. The case study has been applied to a medical imaging system, evolving it into a service model.

Adaptive partitioning for large-scale dynamic graphs

In the last years, large-scale graph processing has gained increasing attention, with most recent systems placing particular emphasis on latency. One possible technique to improve runtime performance in a distributed graph processing system is to reduce network communication. The most notable way to achieve this goal is to partition the graph by minimizing the number of edges that connect vertices assigned to different machines, while keeping the load balanced. However, real-world graphs are highly dynamic, with vertices and edges being constantly added and removed. Carefully updating the partitioning of the graph to reflect these changes is necessary to avoid the introduction of an extensive number of cut edges, which would gradually worsen computation performance. In this paper we show that performance degradation in dynamic graph processing systems can be avoided by adapting continuously the graph partitions as the graph changes. We present a novel highly scalable adaptive partitioning strategy, and show a number of refinements that make it work under the constraints of a large-scale distributed system. The partitioning strategy is based on iterative vertex migrations, relying only on local information. We have implemented the technique in a graph processing system, and we show through three real-world scenarios how adapting graph partitioning reduces execution time by over 50% when compared to commonly used hash-partitioning.

Exploiting hashtags for adaptive microblog crawling

Researchers have capitalized on microblogging services, such as Twitter, for detecting and monitoring real world events. Existing approaches have based their conclusions on data collected by monitoring a set of pre-defined keywords. In this paper, we show that this manner of data collection risks losing a significant amount of relevant information. We then propose an adaptive crawling model that detects emerging popular hashtags, and monitors them to retrieve greater amounts of highly associated data for events of interest. The proposed model analyzes the traffic patterns of the hashtags collected from the live stream to update subsequent collection queries. To evaluate this adaptive crawling model, we apply it to a dataset collected during the 2012 London Olympic Games. Our analysis shows that adaptive crawling based on the proposed Refined Keyword Adaptation algorithm collects a more comprehensive dataset than pre-defined keyword crawling, while only introducing a minimum amount of noise.

Apache and Eclipse: Comparing Open Source Project Incubators

A two-stage incubation model based on analysis of Apache and Eclipse processes might help other organizations build their own incubation process and better manage risks. The popularity of free and open source software has boosted the creation of several kinds of communities around F/OSS projects. Successful communities such as GNU, Mozilla, the Apache Software Foundation, and the Eclipse Foundation drive innovation while delivering high-quality, enterprise-class software. Yet, because communities are composed of loosely coordinated contributors mainly guided by practice, no shared agreement exists on a single set of methods and processes.

An Autonomous Engine for Services Configuration and Deployment

The runtime management of the infrastructure providing service-based systems is a complex task, up to the point where manual operation struggles to be cost effective. As the functionality is provided by a set of dynamically composed distributed services, in order to achieve a management objective multiple operations have to be applied over the distributed elements of the managed infrastructure. Moreover, the manager must cope with the highly heterogeneous characteristics and management interfaces of the runtime resources. With this in mind, this paper proposes to support the configuration and deployment of services with an automated closed control loop. The automation is enabled by the definition of a generic information model, which captures all the information relevant to the management of the services with the same abstractions, describing the runtime elements, service dependencies, and business objectives. On top of that, a technique based on satisfiability is described which automatically diagnoses the state of the managed environment and obtains the required changes for correcting it (e.g., installation, service binding, update, or configuration). The results from a set of case studies extracted from the banking domain are provided to validate the feasibility of this proposal.

System Virtualization Tools for Software Development

The configuration complexity of preproduction sites coupled with access-control mechanisms often impede the software development life cycle. Virtualization is a cost-effective way to remove such barriers and provide a test environment similar to the production site, reducing the burden in IT administrators. An eclipse-based virtualization tool framework can offer developers a personal runtime environment for launching and testing their applications. The authors have followed a model-driven architecture (MDA) approach that integrates best-of-breed virtualization technologies, such as Xen and VDE.

Open Connect Everywhere: A Glimpse at the Internet Ecosystem through the Lens of the Netflix CDN

The importance of IXPs to interconnect different networks and exchange traffic locally has been well studied over the last few years. However, far less is known about the role IXPs play as a platform to enable large-scale content delivery and to reach a world-wide customer base. In this paper, we study the infrastructure deployment of a content hypergiant, Netflix, and show that the combined worldwide IXP substrate is the major corner stone of its Content Delivery Network. This highlights the additional role that IXPs play in the Internet ecosystem, not just in terms of interconnection, but also allowing players such as Netflix to deliver significant amounts of traffic.

A Service Component Deployment Architecture for e-Banking

Service-oriented architectures (SOA) foster software reuse and loose coupling by means of strongly restricting interactions to service contracts. Many companies have identified in SOA an opportunity not only to improve their productivity but also to promote and extend their B2B relationships. The ITECBAN project is a significant reference of this process within the Spanish banking market. The scope of this paper is the implementation of the SOA paradigm in enterprise-class environments based on JEE technology. SCA (Service Component Architecture) and JBI (Java Business Integration) specifications have taken the first steps to support deployment of distributed services at the server-side Java platform. However, significant issues such as runtime service version management and context adaptation are still open. This paper presents a deployment solution for service-oriented JEE distributed systems based upon available specifications (SCA, OSGi and OMG Deployment and Configuration) and OSS implementations.

An Open Source Platform for the Integration of Distributed Services

Service-orientation is not only a means for systems integration, but also an architecture paradigm for building systems. Flexibility, adaptability and interoperability are some of the benefits derived from the adoption of SOA. These principles are often applied to build distributed systems. But whether SOA is applied or not, building a distributed system is still complex, what increases the demand on high-quality middleware to achieve success. This paper presents a runtime service integration architecture that enables distributed service interactions regardless the capabilities of the devices involved, i.e. to deal with services distribution over a heterogeneous network. The solution presented is built upon the OSGi service platform which has been leveraged with OSS middleware components to provide remote communications (with connectors and adaptors), service discovery, service binding and service publication. The development of this architecture is carried out within the ITEA OSIRIS Consortium and is being applied to industrial case studies; including a tax administration applications, service provisioning to residential environments and a mobile CRM.