hybrid lattice tower
300087
Using attribute value lattice to find closed frequent itemsets
Finding all closed frequent itemsets is a key step of association rule mining since the non redundant association rule can be inferred from all the closed frequent itemsets. In this paper we present a new method for finding closed frequent itemsets based on attribute value lattice. In the new method, we argue that vertical data representation and attribute value lattice can find all closed frequent itemsets efficiently, thus greatly improve the efficiency of association rule mining algorithm. We discuss how these techniques and methods are applied to find closed frequent itemsets. In our method, the data are represented vertically; each frequent attribute value is associated with its granule, which is represented as a hybrid bitmap. Based on the partial order defined between the attribute values among the databases, an attribute value lattice is constructed, which is much smaller compared with the original databases. Instead of searching all the items in the databases, which is adopted by almost all the association rule algorithms to find frequent itemsets, our method only searches the attribute value lattice. A bottom up breadth first approach is employed to search the attribute value lattice to find the closed frequent itemsets.
SPIE Defense Commercial Sensing
Tsau Young Lin Xiaohua Hu Eric Louie
14790516
CellSense: An Accurate Energy Efficient GSM Positioning System
Context aware applications have been gaining huge interest in the last few years. With cell phones becoming ubiquitous computing devices, cell phone localization has become an important research problem. In this paper, we present CellSense, which is a probabilistic received signal strength indicator (RSSI) based fingerprinting location determination system for Global System for Mobile Communications (GSM) phones. We discuss the challenges of implementing a probabilistic fingerprinting localization technique in GSM networks and present the details of the CellSense system and how it addresses these challenges. We then extend the proposed system using a hybrid technique that combines probabilistic and deterministic estimations to achieve both high accuracy and low computational overhead. Moreover, the accuracy of the hybrid technique is robust to changes in its parameter values. To evaluate our proposed system, we implemented CellSense on Android based phones. Results from two different testbeds, representing urban and rural environments, for three different cellular providers show that CellSense provides at least 108.57% enhancement in accuracy in rural areas and at least 89.03% in urban areas compared with current state of the art RSSI based GSM localization systems. In additional, the proposed hybrid technique provides more than 6 and 5.4 times reduction in computational requirements compared with state of the art RSSI based GSM localization systems for rural and urban testbeds, respectively. We also evaluate the effect of changing the different system parameters on the accuracy complexity tradeoff and how the cell tower and fingerprint densities affect system performance.
IEEE Transactions on Vehicular Technology
Mohamed Ibrahim Moustafa Youssef
45744661
Reliability Based Optimal Design of Electrical Transmission Towers Using Multi Objective Genetic Algorithms
A hybrid methodology for performing reliability based structural optimization of three dimensional trusses is presented. This hybrid methodology links the search and optimization capabilities of multi objective genetic algorithms (MOGA) with structural performance information provided by finite element reliability analysis. To highlight the strengths of the proposed methodology, a practical example is presented that concerns optimizing the topology, geometry, and member sizes of electrical transmission towers. The weight and reliability index of a tower are defined as the two objectives used by MOGA to perform Pareto ranking of tower designs. The truss deformation and the member stresses are compared to threshold values to assess the reliability of each tower under wind loading. Importance sampling is used for the reliability analysis. Both the wind pressure and the wind direction are considered as random variables in the analysis. The research results presented demonstrate the benefit of implementing MOGA optimization as an integral part of a reliability based optimization procedure for three dimensional trusses.
Comput. Aided Civ. Infrastructure Eng.
Sachin Mathakari Paolo Gardoni Pranab Agarwal Anne M Raich Terje Haukaas
673663
Design of a new independently mobile reconfigurable modular robot
A new self reconfigurable robot is presented. The robot is a hybrid chain/lattice design with several novel features. An active mechanical docking mechanism provides inter module connection, along with optical and electrical interface. The docking mechanisms function additionally as driven wheels. Internal slip rings provide unlimited rotary motion to the wheels, allowing the modules to move independently by driving on flat surfaces, or in assemblies negotiating more complex terrain. Modules in the system are mechanically homogeneous, with three identical docking mechanisms within a module. Each mechanical dock is driven by a high torque actuator to enable movement of large segments within a multi module structure, as well as low speed driving. Preliminary experimental results demonstrate locomotion, mechanical docking, and lifting of a single module.
2010 IEEE International Conference on Robotics and Automation
Michael Dennis Mays Kutzer Matthew S Moses Christopher Y Brown David H Scheidt Gregory S Chirikjian Mehran Armand
114386739
Flexible dynamic analysis of an offshore wind turbine installed on a floating spar platform
Flexible dynamic analysis is a critical process in designing offshore wind turbines that are composed of several huge components. This process was implemented with a hybrid method of finite element multibody system using commercial software in this article. Based on this method, the tower and blades were modeled as flexible components using three dimensional solid elements. The effect of flexible deformation of the tower and blades on the global motions of the floating wind turbine was investigated by comparing the simulation results from the flexible body modeling with those from the rigid body modeling. The tower, blades, and spar platform were divided into sections according to the geometry configuration of the 5 MW OC3 Hywind floating wind turbine. The time and position dependent loads, coming from the wind, wave, and mooring system, were expressed approximately with respect to the divided sections. The relationships between the global motions and the external loads were studied, which indicated that the wind loads had dominant influences on the translational motions and the rotational motions were mainly generated by the propagating waves.
Xiangqian Zhu Wan-Suk Yoo
15690461
Wireless Network Design for Transmission Line Monitoring in Smart Grid
In this paper, we develop a real time situational awareness framework for the electrical transmission power grid using Wireless Sensor Network (WSN) While WSNs are capable of cost efficient monitoring over vast geographical areas, several technical challenges exist. The low power, low data rate devices cause bandwidth and latency bottlenecks. In this paper, our objective is to design a wireless network capable of real time delivery of physical measurements for ideal preventive or corrective control action. For network design, we formulate an optimization problem with the objective of minimizing the installation and operational costs while satisfying the end to end latency and bandwidth constraints of the data flows. We study a hybrid hierarchical network architecture composed of a combination of wired, wireless and cellular technologies that can guarantee low cost real time data monitoring. We formulate a placement problem to find the optimal location of cellular enabled transmission towers. Further, we present evaluation results of the optimization solution for diverse scenarios. Our formulation is generic and addresses real world scenarios with asymmetric sensor data generation, unreliable wireless link behavior, non uniform cellular coverage, etc. Our analysis shows that a transmission line monitoring framework using WSN is indeed feasible using available technologies. Our results show that wireless link bandwidth can be a limiting factor for cost optimization.
IEEE Transactions on Smart Grid
Benazir Fateh G Manimaran Venkataramana Ajjarapu
110113900
Global Local Optimization of Flapping Kinematics in Hovering Flight
The kinematics of a hovering wing are optimized by combining the 2 d unsteady vortex lattice method with a hybrid of global and local optimization algorithms. The objective is to minimize the required aerodynamic power under a lift constraint. The hybrid optimization is used to efficiently navigate the complex design space due to wing wake interference present in hovering aerodynamics. The flapping wing is chosen so that its chord length and flapping frequency match the morphological and flight properties of two insects with different masses. The results suggest that imposing a delay between the different oscillatory motions defining the flapping kinematics, and controlling the way through which the wing rotates at the end of each half stroke can improve aerodynamic power under a lift constraint. Furthermore, our optimization analysis identified optimal kinematics that agree fairly well with observed insect kinematics, as well as previously published numerical results.
Mehdi Ghommem Muhammad R Hajj Dean T Mook Bret Stanford Philip S Beran Layne T Watson
53786151
Physically based enhancement in shallow water resimulation
To resimulate a customized fluid derived product by analyzing an existing fluid is significant and difficult. This paper proposes a driven model recovery method, which is challenging in fluid resimulation customization. First, fluid physical properties are calculated under the constraints of appearance and dynamic behavior of the example water. Second, a hybrid particle lattice Boltzmann method for shallow water (LBMSW) is recovered from the dynamic geometry on fluid surface. As it is found that the resimulation details fade gradually with LBMSW auto advection, a physically based enhancement scheme is presented. A nonlinear algorithm is introduced to stretch the faded density to retain resimulation details. Experiments show that the proposed approach can obtain more realistic resimulation products in several challenging scenarios.
Int. J. Model. Simul. Sci. Comput.
Hongyan Quan Yahui Song Xinquan Zhou Li Zhang
32525423
Human error assessment in electric power company of Serbia.
This paper presents a case study which confirmed that the use of APJ for proper assessment of human error in the Electric Power Company of Serbia (hereinafter EPS) The proposal methodological framework was used for human error identification and quantification in the case of a repair intervention on a steel lattice tower 10/0.4 kV (jurisdiction of an EPS subsidiary ED "Jugoistok" Nis, Serbia) which resulted in an accident with a fatal outcome. One of the aims of this study is to show the necessity of human error assessment not only in manufacturing industries but, as it will be shown in this paper, in companies that distribute electric energy, as well.
Work
Evica Stojiljkovic Miroljub Grozdanovic Predrag Stojiljkovic
205174965
Global sensitivity analysis of a feedback controlled stochastic process model
Abstract The purpose of the study was to investigate whether global sensitivity analysis can be utilised in concurrent process and control design to gain insight into the process and its control. This paper addresses the issue of sensitivity of a control law performance to its parameters in a dynamic, hybrid deterministic stochastic process model. The control law under investigation is a collection of single input, single output type tower level controllers in a papermaking process. Global sensitivity analysis is shown to attribute higher importance to certain key parameters, thus providing valuable insight for the designer.
Simul. Model. Pract. Theory
Jouni Savolainen