Robust execution of service workflows using redundancy and advance reservations

In this paper, we develop a novel algorithm that allows service consumers to execute business processes (or workflows) of interdependent services in a dependable manner within tight time-constraints. In particular, we consider large inter-organisational service-oriented systems, where services are offered by external organisations that demand financial remuneration and where their use has to be negotiated in advance using explicit service-level agreements (as is common in Grids and cloud computing). Here, different providers often offer the same type of service at varying levels of quality and price. Furthermore, some providers may be less trustworthy than others, possibly failing to meet their agreements. To control this unreliability and ensure end-to-end dependability while maximising the profit obtained from completing a business process, our algorithm automatically selects the most suitable providers. Moreover, unlike existing work, it reasons about the dependability properties of a workflow, and it controls these by using service redundancy for critical tasks and by planning for contingencies. Finally, our algorithm reserves services for only parts of its workflow at any time, in order to retain flexibility when failures occur. We show empirically that our algorithm consistently outperforms existing approaches, achieving up to a 35-fold increase in profit and successfully completing most workflows, even when the majority of providers fail

Cooperative fault-tolerant distributed computing U.S. Department of Energy Grant DE-FG02-02ER25537 Final Report

The Harness project has developed novel software frameworks for the execution of high-end simulations in a fault-tolerant manner on distributed resources. The H2O subsystem comprises the kernel of the Harness framework, and controls the key functions of resource management across multiple administrative domains, especially issues of access and allocation. It is based on a “pluggable” architecture that enables the aggregated use of distributed heterogeneous resources for high performance computing. The major contributions of the Harness II project result in significantly enhancing the overall computational productivity of high-end scientific applications by enabling robust, failure-resilient computations on cooperatively pooled resource collections

Solving resource-constrained construction scheduling problems with overlaps by metaheuristic

The paper concerns the problem of roadworks scheduling executed in the flow-shop system. Works may be performed parallelly with the acceleration (overlaps) of construction project, i.e. the following work on the assembly line can begin before the completion of the predecessor work. Taking into account the acceleration enables accurate modeling of complex real construction processes. The above fact can greatly shorten the time of realization of construction process which has a direct impact on reducing costs. The considered issue belongs to the class of NP-hard problems. We introduce the new: mathematical model, specific properties as an acceleration tools, as well as two new optimization algorithms for the problem considered: construction and tabu search. The execution of algorithms was illustrated on the example of a case study concerning the construction of roads. They were also verified on the examples taken from the literature and on already completed construction processes. The obtained results are fully satisfactory. The assigned execution times are close to optimal. The presented methods allow its practitioners (both the planners and the managers) to include in the model the acceleration of the works and the design of a much more efficient construction scheduling. The presented new scheduling method leads to a more competitive environment for contraction companies

Scheduling Moldable Tasks for Dynamic {SMP} Clusters in {S}o{C} Technology

The paper presents an algorithm for scheduling parallel programs for execution in a parallel architecture based on dynamic SMP processor clusters with data transfers on the fly. The algorithm is based on the concept of moldable computational tasks. First, an initial program graph is decomposed into sub­graphs, which are then treated as moldable tasks. So identified moldable tasks are then scheduled using an algorithm with warranted schedule length

Modular FEM framework "ModFem" for generic scientific parallel simulations

We present the design and its' implementation for a flexible and robust parallel modular finite element (FEM) framework, called ModFem. The design is based on reusable modules which use narrow and well-defined interfaces to cooperate. At the top of the architecture there are problem dependent modules. Problem dependent modules can be additionally grouped together by "super-modules". This structure allows for applying the sequential codes to parallel environments and also support solving multi-physics and multi-scale problems