Towards Practical Graph-Based Verification for an Object-Oriented Concurrency Model

To harness the power of multi-core and distributed platforms, and to make the development of concurrent software more accessible to software engineers, different object-oriented concurrency models such as SCOOP have been proposed. Despite the practical importance of analysing SCOOP programs, there are currently no general verification approaches that operate directly on program code without additional annotations. One reason for this is the multitude of partially conflicting semantic formalisations for SCOOP (either in theory or by-implementation). Here, we propose a simple graph transformation system (GTS) based run-time semantics for SCOOP that grasps the most common features of all known semantics of the language. This run-time model is implemented in the state-of-the-art GTS tool GROOVE, which allows us to simulate, analyse, and verify a subset of SCOOP programs with respect to deadlocks and other behavioural properties. Besides proposing the first approach to verify SCOOP programs by automatic translation to GTS, we also highlight our experiences of applying GTS (and especially GROOVE) for specifying semantics in the form of a run-time model, which should be transferable to GTS models for other concurrent languages and libraries.Comment: In Proceedings GaM 2015, arXiv:1504.0244

Data-centric concurrency control on the java programming language

Dissertação para obtenção do Grau de Mestre em Engenharia InformáticaThe multi-core paradigm has propelled shared-memory concurrent programming to an important role in software development. Its use is however limited by the constructs that provide a layer of abstraction for synchronizing access to shared resources. Reasoning with these constructs is not trivial due to their concurrent nature. Data-races and deadlocks occur in concurrent programs, encumbering the programmer and further reducing his productivity. Even though the constructs should be as unobtrusive and intuitive as possible, performance must also be kept high compared to legacy lock-based mechanism. Failure to guarantee similar performance will hinder a system from adoption. Recent research attempts to address these issues. However, the current state of the art in concurrency control mechanisms is mostly code-centric and not intuitive. Its codecentric nature requires the specification of the zones in the code that require synchronization,contributing to the decentralization of concurrency bugs and error-proneness of the programmer. On the other hand, the only data-centric approach, AJ [VTD06], exposes excessive detail to the programmer and fails to provide complete deadlock-freedom. Given this state of the art, our proposal intends to provide the programmer a set of unobtrusive data-centric constructs. These will guarantee desirable security properties: composability, atomicity, and deadlock-freedom in all scenarios. For that purpose, a lower level mechanism (ResourceGroups) will be used. The model proposed resides on the known concept of atomic variables, the basis for our concurrency control mechanism. To infer the efficiency of our work, it is compared to Java synchronized blocks, transactional memory and AJ, where our system demonstrates a competitive performance and an equivalent level of expressivity.RepComp project(PTDC/EIA-EIA/108963/2008

Optimized Surface Code Communication in Superconducting Quantum Computers

Quantum computing (QC) is at the cusp of a revolution. Machines with 100 quantum bits (qubits) are anticipated to be operational by 2020 [googlemachine,gambetta2015building], and several-hundred-qubit machines are around the corner. Machines of this scale have the capacity to demonstrate quantum supremacy, the tipping point where QC is faster than the fastest classical alternative for a particular problem. Because error correction techniques will be central to QC and will be the most expensive component of quantum computation, choosing the lowest-overhead error correction scheme is critical to overall QC success. This paper evaluates two established quantum error correction codes---planar and double-defect surface codes---using a set of compilation, scheduling and network simulation tools. In considering scalable methods for optimizing both codes, we do so in the context of a full microarchitectural and compiler analysis. Contrary to previous predictions, we find that the simpler planar codes are sometimes more favorable for implementation on superconducting quantum computers, especially under conditions of high communication congestion.Comment: 14 pages, 9 figures, The 50th Annual IEEE/ACM International Symposium on Microarchitectur

Beyond TRIPS: Why the WTO's Doha Round is Unhealthy

OA Monitor ExerciseOA Monitor ExerciseOA Monitor ExerciseThe current round of World Trade Organization (wto) negotiations—the Doha Round—has significant implications for global health which have received insufficient attention from the global health community. All too often the health implications of global trade agreements are examined only after their conclusion, and are concerned only with intellectual property rights. This paper seeks to move beyond this narrow focus and elucidate the wider health implications of the Doha Round. It explores the negative effect of the Round on state capacity to provide and regulate health services in low-income countries, and the impact it will have on livelihoods among the poor and their ability to access health services. Overall the paper makes the case for greater engagement from the health community with the wto and the Doha Round negotiations beyond the customary focus on intellectual property rights

Submicron Systems Architecture Project: Semiannual Technial Report

No abstract available

Submicron Systems Architecture: Semiannual Technical Report

No abstract available

Spectrum Allocation for 3G in Philippines: Implications for Policy Makers and Regulators

The commercial potential of wireless applications has brought spectrum policies to the forefront of regulatory arena. The visibility of the telecom sector and the prior experience of 3G licensing in Europe and UK have made several Asian regulators and policy makers wary of using auctions. This paper details out the beauty contest approach adopted by NTC to allocate 3G licenses and the issues that arose as a consequence and highlights the influence of global developments (European and UK 3G auctions) on domestic spectrum allocation processes. The adoption of the beauty contest approach and fixed license fee was justified by NTC on the grounds of ensuring lower prices to consumers but it led to criticism that it was a clear violation of law, as NTC was mandated to promote competition. In this context, auctions would have been a better and more economically efficient process. The case study highlights the importance of incorporating economic principles, design of a transparent evaluation criteria and communication of the same to the bidders prior to the event. Policy makers need to recognize that well designed auctions are transparent mechanism to allocate scarce resource to those entities who value it most. While beauty contests may appear to be simple mechanisms to administer, lack of clarity in design could lead to non transparency and subsequent possibility of litigation and delays. The study also brings out that although an open consultative approach in the early stages may appear to delay the process, in the long run, it leads to more transparent and robust solutions.

Northeast Cultural Values and Principles, Good Governance and Conflict Reduction: A Bodo Socio-Cultural Framework

This article proposes a solution to problems occurring in Northeast India that result in conflict – that are the consequences of the prior approach to development and governance. The article argues that the problems can be solved in a way compatible with micro level cultural values and that benefit stakeholders at the local, regional, and national levels by integrating Amartya Sen’s approach to freedom with the Creating Public Value Theory (i.e. state-of-the-art strategies for freedom and good governance). The article uses an exploratory study of relevant literature as a method to analyze the dynamics of Northeast India and to explain how recent scholarship on Development as Freedom, multi-level governance, Creating Public Value, and social networking contribute to conflict reduction and peacebuilding. Bodo culture is used as a context to demonstrate the viability and applicability of the model. The article contributes to literature on good governance, interethnic relation, conflict resolution, and peacebuilding