38263878
A Longest Cycle Version of Tutte's Wheels Theorem
An edgeeof a minimally 3-connected graphGis non-essential if and only if the graph obtained by contractingefromGis both 3-connected and simple. Suppose thatGis not a wheel. Tutte's Wheels Theorem states thatGhas at least one non-essential edge. We show that each longest cycle ofGcontains at least two non-essential edges. Moreover, each cycle ofGwhose edge set is not contained in a fan contains at least two non-essential edges. We characterize the minimally 3-connected graphs which contain a longest cycle containing exactly two non-essential edges.
31035436
Contractible Elements in Graphs and Matroids
Let G be a simple 3-connected graph with at least five vertices. Tutte [13] showed that G has at least one contractible edge. Thomassen [11] gave a simple proof of this fact and showed that contractible edges have many applications. In this paper, we show that there are at most $\frac{|V(G)|}{5}$ vertices that are not incident to contractible edges in a 3-connected graph G. This bound is best-possible. We also show that if a vertex v is not incident to any contractible edge in G, then v has at least four neighbours having degree three, and each such neighbour is incident to exactly two contractible edges. We give short proofs of several results on contractible edges in 3-connected graphs as well. We also study the contractible elements for k-connected matroids. We partially solve an open problem for regular matroids.
9516398
The CenSSIS image database
The CenSSIS image database is a scientific database that enables effective data management and collaboration to accelerate fundamental research. This paper describes the design and use of a state-of-the-art relational image database management system, accessible through a standard Web-browser interface. The application utilizes a robust security architecture and is designed for efficient data submission. Our database query engine provides complex query capabilities to facilitate fast and efficient data retrieval. The system offers a highly extensible metadata schema, with the option of storing data within a hierarchical format.
546715
Minimising the Energy Consumption of Real-Time Tasks with Precedence Constraints on a Single Processor
Energy-aware task scheduling is critical for real-time embedded systems. Although dynamic power has traditionally been a primary source of processor power consumption, leakage power is becoming increasingly important. In this paper, we present two optimal energy-aware polynomial-time algorithms for scheduling a set of tasks with release times, deadlines and precedence constraints on a single processor with continuous voltages. Our algorithms are guaranteed to minimise the total energy consumption of all tasks while minimising their maximum lateness under two power models: the dynamic power model where the dynamic power dominates the processor power consumption and the dynamic and leakage power model where both dynamic power and leakage power are significant sources of the processor power consumption. The time complexities of both algorithms are O(n3) , where n is the number of tasks
12829985
Type-2 Fuzzistics for Symmetric Interval Type-2 Fuzzy Sets: Part 2, Inverse Problems
In Part 1 of this two-part paper, we bounded the centroid of a symmetric interval type-2 fuzzy set (T2 FS), and consequently its uncertainty, using geometric properties of its footprint of uncertainty (FOU). We then used these bounds to solve forward problems, i.e., to go from parametric interval T2 FS models to data. The main purpose of the present paper is to formulate and solve inverse problems, i.e., to go from uncertain data to parametric interval T2 FS models, which we call type-2 fuzzistics. Given interval data collected from people about a phrase, and the inherent uncertainties associated with that data, which can be described statistically using the first- and second-order statistics about the end-point data, we establish parametric FOUs such that their uncertainty bounds are directly connected to statistical uncertainty bounds. These results should find applicability in computing with words
7266719
Two processor scheduling with real release times and deadlines
In a hard real-time system, critical tasks are subject to timing constraints such as release times and deadlines. All timing constraints must be satisfied when tasks are executed. Nevertheless, given a set of tasks, finding a feasible schedule which satisfies all timing constraints is NP-complete even on one processor.In this paper, we study the following special non-pre-emptive two processor scheduling problem: Given a set of UET (Unit Execution Time) tasks with arbitrary precedence constraints, individual real release times and deadlines, find a feasible schedule on two identical processors whenever one exists. The complexity status of this problem has been open for a long time. we propose the first polynomial algorithm for this problem. Our algorithm is underpinned by the key consistency notion: successor-tree-consistency. The time complexity of our algorithm is O(n4), where n is the number of tasks.
16198255
Accurate Emulation of Wireless Sensor Networks
Wireless sensor networks (WSNs) have a wide range of useful, data-centric applications, and major techniques involved in these applications include in-network query processing and query-informed routing. Both techniques require realistic environments and detailed system feedback for development and evaluation. Unfortunately, neither real sensor networks nor existing simulators/emulators are suitable for this requirement. In this design paper, we propose a distributed sensor network emulator, a Virtual Mote Network (VMNet), to meet this requirement. We describe the system architecture, the synchronization of the nodes and the virtual time emulation with a focus on mechanisms that are effective for accurate emulation.