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We aim to solve the OPF problem by defining contingency scenarios involved in the optimization problem by means of a SDP relaxation. Contingency scenarios are performed for the IEEE 39-bus system. Contingency analyses are performed by generation and line losses. Contingency scenarios are considered to be possible events. These events may be single contingencies, such as a generation unit failures...
To improve the effective utilisation of its supercomputing platforms, the New Zealand eScience Infrastructure (NeSI) offers, in addition to user support and the installation of a comprehensive software stack, a consultancy service to some of its users. Here we present lessons learned from this work and how additional improvements can be made to further enhance productivity of researchers on computing...
We give a nearly linear-time randomized approximation scheme for the Held-Karp bound [22] for Metric-TSP. Formally, given an undirected edge-weighted graph G = (V,E) on m edges and ε 0, the algorithm outputs in O(m log^4 n/ε^2) time, with high probability, a (1 + ε)-approximation to the Held-Karp bound on the Metric-TSP instance induced by the shortest path metric...
ForkJoin framework is a widely used parallel programming framework upon which both core concurrency libraries and real-world applications are built. Beneath its simple and user-friendly APIs, ForkJoin is a sophisticated managed parallel runtime unfamiliar to many application programmers: the framework core is a work-stealing scheduler, handles fine-grained tasks, and sustains the pressure from automatic...
Energy efficiency has gradually become an important factor for improving the user experience of smartphones. Many background applications continue to consume energy without users' awareness, because these applications use wakelock to prevent the device from going to sleep state, while such misused will cause no-sleep bugs. In this paper, a framework for sensing wakelock application and mining users'...
In this work is proposed a solution method for the optimal power flow (OPF) problem, including the synchronous generator capability curve constraints (SGCC). OPF is a non-convex, non-linear, and hard to solve optimization problem. When synchronous generator operational limits are not concerned, OPF solution could not be applicable in real scenarios, taking the machine to operate with winding currents...
Multithread programming tools become popular for exploitation of high performance processing with the dissemination of multicore processors. In this context, it is also popular to exploit compiler optimization to improve the performance at execution time. In this work, we evaluate the performance achieved by the use of flags -O1, -O2, and -O3 of two C compilers (GCC and ICC) associated with five different...
In this paper, we propose a sparse beamforming based energy efficiency (EE) maximization problem for multi-user distributed antenna systems (DASs). In DAS, the power consumption of remote antenna units (RAUs) and corresponding backhaul links have an important influence on the whole network efficiency. Hence this paper addresses RAU selection. We select optimal RAUs and corresponding backhaul links...
Field-Programmable Gate Arrays (FPGAs) are gaining considerable momentum in mainstream high-performance systems in recent years due to their flexibility and low power consumption. Still, FPGAs remain largely unavailable to software programmers due to programming and debugging difficulties that are inherent to standard Hardware Description Languages. The performance that hardware-oblivious software...
Field-Programmable Gate Arrays (FPGAs) are gaining considerable momentum in mainstream high-performance systems in recent years due to their flexibility and low power consumption. Still, FPGAs remain largely unavailable to software programmers due to programming and debugging difficulties that are inherent to standard Hardware Description Languages. The performance that hardware-oblivious software...
Aggregators are market participants that bridge the gap between the bulk electricity market and the emerging active end-user (smart home) by efficiently scheduling or allocating resources to meet certain objectives in the electricity grid. The computational burden and processing time of such allocation problems increases with the number of resources. Using high performance computing and parallel processing...
The paper presents a two-stage model for achieving feasible optimal solution along with numerical validation for the exactness of the available second order cone relaxation in the distribution optimal power flow problem. To this end, the IEEE 13-bus, 34-bus and 123-bus distribution power systems are adapted by balancing the various feeder segments and by populating selected nodes with photovoltaic...
Future main memory will likely include Non-Volatile Memory. Non-Volatile Main Memory (NVMM) provides an opportunity to rethink checkpointing strategies for providing failure safety to applications. While there are many checkpointing and logging schemes in literature, their use must be revisited as they incur high execution time overheads as well as a large number of additional writes to NVMM, which...
We describe CPU and GPU implementations of parallel triangle-counting and k-truss identification in the Galois and IrGL systems. Both systems are based on a graph-centric abstraction called the operator formulation of algorithms. Depending on the input graph, our implementations are two to three orders of magnitude faster than the reference implementations provided by the IEEE HPEC static graph challenge.
In this paper, we focus on optimization problem of a lens contour data for high precision in the lens edger. When the lens edger recognizes a lens contour, the measurement error in the lens contour data appears due to some factors. In this paper, we modify the lens contour data to suitable one to grind lens based on nonlinear optimization scheme, which realizes higher precision and quality of lens...
The objective of this work is to investigate wind uncertainty within a long term generation and transmission expansion planning framework. Specifically, this work investigates uncertainty associated with wind power within a 2 stage stochastic program and quantifies its importance with the well known quantities “Value of Stochastic Solution” VSS and “Expected Value of Perfect Information” EVPI. Simulations...
This paper deals with the evaluation of FPGAs resurgence for hardware acceleration applied to computed tomography on the back-projection operator used in iterative reconstruction algorithms. We focus our attention on the tools developed by FPGAs manufacturers, in particular the Intel FPGA SDK for OpenCL, that promises a new level of hardware abstraction from the developer's perspective, allowing a...
Offering strategy of a price-maker demand response aggregator (DRA) in a two-settlement market is presented in this paper. The aggregator minimizes its cost by offering energy and price bids in the day-ahead market and energy bids in the balancing market. On the other hand, DRA optimally manages the aggregated demands of a large number of electric vehicles and properly distributes them through the...
This paper presents a dynamic collision avoidance controller of a connected vehicle group using Model Predictive Control (MPC). The vehicles should follow a predefined reference trajectory while simultaneously avoiding collisions on this trajectory. MPC pursues the tracking of the reference trajectory in the objective function of the optimization problem. In order to avoid collisions, MPC defines...
We study the problem of interference mitigation in a phased array, where a subset containing k out of a total of N receivers creates a virtual spatial null for an incoming interference. The signal-of-interest and interference are represented by their corresponding steering vectors, and an optimum subarray is chosen such that the two vectors are as orthogonal as possible. This optimization is a binary...
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