Concurrency

The risk of New Product Development (NPD) investments is that
they are wasted if users and customers do not accept their results. Living Labs
set out to involve users early on in the process to reduce this risk. The paper
tells the story of how Coliquio discusses the contribution of Living Labs to
NPD. User acceptance is a well-known performance indicator for new product
success and user-involvement an indicator of development process maturity.
As the story suggests, the nature of Living Labs as innovation intermediary is
coordination of NPD processes in open-network settings. The paper provides a
framework of Living Lab capabilities including team mobilisation and idea
scouting, match making, product development, user validation and market
positioning, project financing and venturing for future growth. Their concurrent
coordination is a capability by itself. Living Labs are entrepreneurship
capabilities.

Cet article montre comment Valery Larbaud, sensible à l’émulation littéraire internationale en un temps où la culture française est concurrencée par la vogue d’autres cultures européennes, mais aussi d’autres continents littéraires, a conservé son « amour-propre de littérateur français », selon son expression même.

ProCoS aims to improve dependability, reduce timescales and cut development costs of construction for embedded systems, particularly in real-time and safety-critical applications. It uses and develops the results of basic research into fundamental properties of interactive systems. It aims to provide a scientific basis for future standards of practice in the development of embedded systems, ensuring correctness of all stages in the development, from elicitation and analysis of requirements through design and implementation of programs down
to compilation and execution on verified hardware.

The diffusion of the Next Generation Sequencing (NGS) has increased the amount of data obtainable by genomic experiments. From a DNA sample a NGS run is able to produce millions of short sequences (called reads), which should be mapped into a reference genome. In this paper, we analyse the performance of Bowtie2, a fast and popular DNA mapping tool. Bowtie2 exhibits a multithreading implementation on top of pthreads, spin-locks and SSE2 SIMD extension. From parallel computing viewpoint, is a paradigmatic example of a software requiring to address three fundamental problems in shared-memory programming for cache-coherent multi-core platforms: synchronisation efficiency at very fine grain (due to short reads), load-balancing (due to long reads), and efficient usage of memory subsystem (due to SSE2 memory pressure). We compare the original implementation against an alternative implementation on top of the FastFlow pattern-based programming framework. The proposed design exploits the hi...

Data race conditions in multi-tasking software applications are prevented by serializing access to shared memory resources, ensuring data consistency and deterministic behavior. Traditionally tasks acquire and release locks to synchronize operations on shared memory. Unfortunately, lock management can add significant processing overhead especially for multicore deployments where tasks on different cores convoy in queues waiting to acquire a lock. Implementing more than one lock introduces the risk of deadlock and using spinlocks constrains which cores a task can run on. The better alternative is to eliminate locks and validate that real-time properties are met, which is not directly considered in many embedded applications. Removing the locks is non-trivial and packaging lock-free algorithms for developers reduces the possibility of concurrency defects. This paper details how a multicore communication API implementation is enhanced to support lock-free messaging and the impact this ...

Purpose – XML has spread beyond the computer science fields and reached other areas such as, e-commerce, identification, information storage, instant messaging and others. Data communicated over these domains are now mainly based on XML. Thus, allowing non-expert programmers to manipulate and control their XML data is essential. The purpose of this paper is to present an XA2C framework intended

— Collaborative image annotation is a useful strategy for assigning a set of labels, or keywords to an image, taking into account its content. While existing collaborative image annotation frameworks facilitate sharing, indexing, and understanding of huge number of images, newly-developed methods let group of users manage dynamically-updating data. Conflict-free Replicated Data Type method, used in several collaborative systems, offers to distributed participants through the web a real support to concurrently annotate copies of shared image file regardless of their order. A major benefit of this method, therefore, is to provide a good framework for representing semantic stores and a good mechanism for solving the concurrent updating problem without complex control in collaborative image annotation process. In this paper, we propose a novel optimistic replication approach for collaborative replicated image annotation stores that ensures eventual consistency. We describe how Open Annotation Collaboration can be extended to further support real collaboration between users allowing them to work together effectively to achieve common goals.

There has been a great deal of hype about Amazon’s simple storage service (S3). S3 provides infinite scalability and high availability at low cost. Currently, S3 is used mostly to store multi-media docu-ments (videos, photos, audio) which are shared by a community of people and rarely updated. The purpose of this paper is to demon-strate the opportunities and limitations of using S3 as a storage sys-tem for general-purpose database applications which involve small objects and frequent updates. Read, write, and commit protocols are presented. Furthermore, the cost ($), performance, and consis-tency properties of such a storage system are studied.

There has been a growing interest in programming models for con-currency. Strategies for dealing with shared data amongst parallel threads of execution include immutable (as in Erlang) and locked (as in Python) data structures. A third option exists, called transactional memory (as in Haskell), which includes thread-local journaling for operations on objects which are both mutable and globally shared. Here, we present TraM, a pure Python implementation of the TL2 algorithm for software transactional memory.

Many software development organizations struggle to make informed decisions when investing in new software technologies. The authors' experimental framework can help companies evaluate a new software technology by examining its features in relation to its peers and competitors through a systematic approach that includes modeling experiments

This paper provides a formal specification and proof of correctness of a basic Generalized Snapshot Isolation certification-based data replication protocol for database middleware architectures. It has been modeled using a state transition system, as well as the main system components, allowing a perfect match with the usual deployment in a middleware system. The proof encompasses both safety and liveness properties, as it is commonly done for a distributed algorithm. Furthermore, a crash failure model has been assumed for the correctness proof, although recovery analysis is not the aim of this paper. This allows an easy extension toward a crash-recovery model support in future works. The liveness proof focuses in the uniform commit: if a site has committed a transaction, the rest of sites will either commit it or it would have crashed.

Resumen: En los 74 capítulos de la Segunda parte del Quijote es posible encontrar relaciones complejas entre los capítulos mismos y los episodios que en ellos se narran, un episodio puede narrarse en más de un capítulo al igual que un capítulo puede ser parte de más de un episodio. Parte de la complejidad y conciencia estilística de la obra puede observarse en el análisis de los siete recursos de apertura y cierre de capítulos presentados en este trabajo: suspenso, anuncio, simultaneidad, descanso en la narración, presencia del narrador, apelación al receptor y cambio de espacio de los personajes.

Abstract: In the 74 chapters of Don Quixote's Second part it is possible to find different relations between the chapters and the episodes narrated, one episode can be narrated in more than one chapter as well as one chapter can be part of more than one episode. Some of the novel stylistic complexity and conscience can be observed in the analysis of the seven chapter opening and closing literary devises covered in this work: suspense, advertisement, concurrency, break in the narrative, narrator presence, appeal to the receiver, characters change of space.

The fast evaluation of complex queries on big text corpora is an important feature of corpus managers. The aim of this paper is to apply approaches of concurrent processing to the query evaluation in the corpus management system Manatee. The work contains an evaluation of the query processing speed using various number of cores available, and also a comparison of the length of the source code between the original and the concurrent implementation.

In recent years, the parallel computing community has shown increasing interest in leveraging cloud resources for executing parallel applications. Clouds exhibit several fundamental features of economic value, like on-demand resource provisioning and a pay-per-use model. Additionally, several cloud providers offer their resources with significant discounts; however, possessing limited availability. Such volatile resources are an auspicious opportunity to reduce the costs arising from computations , thus achieving higher cost efficiency. In this paper, we propose a cost model for quantifying the monetary costs of executing parallel applications in cloud environments, leveraging volatile resources. Using this cost model, one is able to determine a configuration of a cloud-based parallel system that minimizes the total costs of executing an application.

Checkpointing with rollback recovery is a well-known method for achieving fault-tolerance in distributed systems. In this work, we introduce algorithms for checkpointing and rollback recovery on asynchronous unidirectional and bi-directional ring networks. The proposed checkpointing algorithms can handle multiple concurrent initiations by different processes. While taking checkpoints, processes do not have to take into consideration any application message dependency. The synchronization is achieved by passing control messages among the processes. Application messages are acknowledged. Each process maintains a list of unacknowledged messages. Here we use a logical checkpoint, which is a standard checkpoint (i.e., snapshot of the process) plus a list of messages that have been sent by this process but are unacknowledged at the time of taking the checkpoint. The worst case message complexity of the proposed checkpointing algorithm is O(kn) when k initiators initiate concurrently. The time complexity is O(n). For the recovery algorithm, time and message complexities are both O(n).

As an important element of the Smart Grid, Advanced Metering Infrastructure (AMI) systems have been implemented and deployed throughout the world in the past several years. An AMI system connects millions of end devices (e.g., smart meters and sensors in the residential level) with utility control centers via an efficient two-way communication infrastructure. AMI systems are able to exchange substantial meter data and control information between utilities and end devices in real-time or near real-time. The major challenge our research was to scale ABB’s Meter Data Management System (MDMS) to manage data that originates from millions of smart meters. We designed a lightweight architecture capable of collect ever-increasing large amount of meter data from various metering systems, clean, analyze, and aggregate the meter data to support various smart grid applications. To meet critical high performance requirements, various concurrency processing techniques were implemented and integrated in our prototype. Our experiments showed that on average the implemented data file parser took about 42 minutes to complete parsing, cleaning, and aggregating 5.184 billion meter reads on a single machine with the hardware configuration of 12-core CPU, 32G RAM, and SSD Hard Drives. The throughput is about 7.38 billion meter reads (206.7GB data) per hour (i.e., 1811TB/year). In addition, well-designed publish/subscribe and communication infrastructures ensure the scalability and flexibility of the system.

Abstract. Exception handling is an important part of software and system architectures. The scale of operations of modern software systems in complex network applications and embedded systems raises numerous possibilities of failures and exception conditions. Over the past two decades, object-oriented design principles and programming techniques coupled with sophisticated engineering tools have significantly reduced the complexity of the design and implementation process for modern software systems. However, integration of suitable exception handling techniques with object-oriented design methodologies and programming models has continued to raise many important research challenges. Whereas several such challenges arise in the context of fundamental constructs in object-orientation, many new research issues are stemming from the unique nature of emerging application environments, requiring domain-specific models for exception handling. This workshop was organized to facilitate discu...