259 research outputs found
Full design of fuzzy controllers using genetic algorithms
This paper examines the applicability of genetic algorithms (GA) in the complete design of fuzzy logic controllers. While GA has been used before in the development of rule sets or high performance membership functions, the interdependence between these two components dictates that they should be designed together simultaneously. GA is fully capable of creating complete fuzzy controllers given the equations of motion of the system, eliminating the need for human input in the design loop. We show the application of this new method to the development of a cart controller
Device-to-Device Communications in the Millimeter Wave Band: A Novel Distributed Mechanism
In spite of its potential advantages, the large-scale implementation of the
device-to-device (D2D) communications has yet to be realized, mainly due to
severe interference and lack of enough bandwidth in the microwave (W)
band. Recently, exploiting the millimeter wave (mmW) band for D2D
communications has attracted considerable attention as a potential solution to
these challenges. However, its severe sensitivity to blockage along with its
directional nature make the utilization of the mmW band a challenging task as
it requires line-of-sight (LOS) link detection and careful beam alignment
between the D2D transceivers. In this paper, we propose a novel distributed
mechanism which enables the D2D devices to discover unblocked LOS links for the
mmW band communication. Moreover, as such LOS links are not always available,
the proposed mechanism allows the D2D devices to switch to the W band if
necessary. In addition, the proposed mechanism detects the direction of the LOS
links to perform the beam alignment. We have used tools from stochastic
geometry to evaluate the performance of the proposed mechanism in terms of the
signal-to-interference-plus-noise ratio (SINR) coverage probability. The
performance of the proposed algorithm is then compared to the one of the single
band (i.e., W/mmW) communication. The simulation results show that the
proposed mechanism considerably outperforms the single band communication.Comment: 6 Pages, 6 Figures, Accepted for presentation in Wireless
Telecommunication Symposium (WTS'18
Efficient parallel architecture for highly coupled real-time linear system applications
A systematic procedure is developed for exploiting the parallel constructs of computation in a highly coupled, linear system application. An overall top-down design approach is adopted. Differential equations governing the application under consideration are partitioned into subtasks on the basis of a data flow analysis. The interconnected task units constitute a task graph which has to be computed in every update interval. Multiprocessing concepts utilizing parallel integration algorithms are then applied for efficient task graph execution. A simple scheduling routine is developed to handle task allocation while in the multiprocessor mode. Results of simulation and scheduling are compared on the basis of standard performance indices. Processor timing diagrams are developed on the basis of program output accruing to an optimal set of processors. Basic architectural attributes for implementing the system are discussed together with suggestions for processing element design. Emphasis is placed on flexible architectures capable of accommodating widely varying application specifics
An intelligent allocation algorithm for parallel processing
The problem of allocating nodes of a program graph to processors in a parallel processing architecture is considered. The algorithm is based on critical path analysis, some allocation heuristics, and the execution granularity of nodes in a program graph. These factors, and the structure of interprocessor communication network, influence the allocation. To achieve realistic estimations of the executive durations of allocations, the algorithm considers the fact that nodes in a program graph have to communicate through varying numbers of tokens. Coarse and fine granularities have been implemented, with interprocessor token-communication duration, varying from zero up to values comparable to the execution durations of individual nodes. The effect on allocation of communication network structures is demonstrated by performing allocations for crossbar (non-blocking) and star (blocking) networks. The algorithm assumes the availability of as many processors as it needs for the optimal allocation of any program graph. Hence, the focus of allocation has been on varying token-communication durations rather than varying the number of processors. The algorithm always utilizes as many processors as necessary for the optimal allocation of any program graph, depending upon granularity and characteristics of the interprocessor communication network
Nonlinear robust controller design for multi-robot systems with unknown payloads
This work is concerned with the control problem of a multi-robot system handling a payload with unknown mass properties. Force constraints at the grasp points are considered. Robust control schemes are proposed that cope with the model uncertainty and achieve asymptotic path tracking. To deal with the force constraints, a strategy for optimally sharing the task is suggested. This strategy basically consists of two steps. The first detects the robots that need help and the second arranges that help. It is shown that the overall system is not only robust to uncertain payload parameters, but also satisfies the force constraints
Systemic Skewness and the Return Behavior of Common Stocks
Duane B. Graddy is Professor of Finance in the Department of Economics and Finance at Middle Tennessee State University . Ghasem Homaifar is an Associate Professor of Finance in the Department of Economics and Finance at Middle Tennessee State University
Controls and guidance research
The objectives of the control group are concentrated on research and education. The control problem of the hypersonic space vehicle represents an important and challenging issue in aerospace engineering. The work described in this report is part of our effort in developing advanced control strategies for such a system. In order to achieve the objectives stated in the NASA-CORE proposal, the tasks were divided among the group based upon their educational expertise. Within the educational component we are offering a Linear Systems and Control course for students in electrical and mechanical engineering. Also, we are proposing a new course in Digital Control Systems with a corresponding laboratory
Option Embedded Bonds: The Convertible Puttable Bond
We derive analytics of duration and convexity for the convertible puttable bond, which offers investors a significant upside potential embedded in the long call as well as downside protection of a long put. The inclusion of a long put in this bond makes the bond relatively more convex than a conventional pure bond, therefore, increasing both duration as well as convexity of this bond. We find that convexity of the convertible puttable bond is the highest when compared to other classes of convertibles as money managers pay a premium to acquire the convexity embedded in this hybrid financial instrumen
APT and Bank Holding Company Stock Returns
Adi S. Kama is Professor of Finance in the Department of Economics and Finance at Indiana University-Purdue University at Fort Wayne. Ghassem Homaifar is an Assistant Professor of Finance in the Department of Economics and Finance at Middle Tennessee State University. Duane B. Graddy is Professor of Finance in the Department of Economics and Finance at Middle Tennessee State University
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