North Carolina State University

About: North Carolina State University is a education organization based out in Raleigh, North Carolina, United States. It is known for research contribution in the topics: Population & Thin film. The organization has 44161 authors who have published 101744 publications receiving 3456774 citations. The organization is also known as: NCSU & North Carolina State University at Raleigh.

FreePDK: An Open-Source Variation-Aware Design Kit

Abstract: This paper discusses an open source, variation aware Process Design Kit (PDK), based on Scalable CMOS design rules, down to 45 nm,for use in VLSI research, education and small businesses. This kit includes all the necessary layout design rules and extraction command decks to capture layout dependent systematic variation and perform statistical circuit analysis. The kit also includes a standard cell and pad library with the necessary support files to enable full chip place and route and verification for System on Chip designs. Test chips designed with this PDK are designed in such a way so that they can be fabricated by fabrication facilities allowing validation of the design rules so that the rules may be used in future multi-project runs and design contests.

A likelihood-based approach to capture-recapture estimation of demographic parameters under the robust design.

Abstract: The Jolly-Seber method has been the traditional approach to the estimation of demographic parameters in long-term capture-recapture studies of wildlife and fish species. This method involves restrictive assumptions about capture probabilities that can lead to biased estimates, especially of population size and recruitment. Pollock (1982, Journal of Wildlife Management 46, 752-757) proposed a sampling scheme in which a series of closely spaced samples were separated by longer intervals such as a year. For this "robust design," Pollock suggested a flexible ad hoc approach that combines the Jolly-Seber estimators with closed population estimators, to reduce bias caused by unequal catchability, and to provide estimates for parameters that are unidentifiable by the Jolly-Seber method alone. In this paper we provide a formal modelling framework for analysis of data obtained using the robust design. We develop likelihood functions for the complete data structure under a variety of models and examine the relationship among the models. We compute maximum likelihood estimates for the parameters by applying a conditional argument, and compare their performance against those of ad hoc and Jolly-Seber approaches using simulation.

A Multiagent-Based Dispatching Scheme for Distributed Generators for Voltage Support on Distribution Feeders

Abstract: This paper illustrates how a multiagent system (MAS)-based scheme can be developed for a control/optimization problem. The prototype problem considered is the dispatching of distributed generators on a distribution feeder to provide voltage support. The popular control net protocol (CNP) for MAS has been adopted to facilitate distributed control. This paper illustrates that characterization of the optimal solution is necessary in order to develop a protocol for the MAS to implement. This paper also shows that MAS facilitates a model-free control procedure, as it can monitor the local sensitivities. Test results, based on simulations on a prototype feeder, show that the proposed MAS-based control scheme is very effective in obtaining the solution for the prototype problem. The proposed method needs fast communication among the distributed generators (DGs) in order to assure fast response during emergency conditions. Communication requirements have also been identified in this paper

On the Levy-Walk Nature of Human Mobility

Abstract: We report that human walks performed in outdoor settings of tens of kilometers resemble a truncated form of Levy walks commonly observed in animals such as monkeys, birds and jackals. Our study is based on about one thousand hours of GPS traces involving 44 volunteers in various outdoor settings including two different college campuses, a metropolitan area, a theme park and a state fair. This paper shows that many statistical features of human walks follow truncated power-law, showing evidence of scale-freedom and do not conform to the central limit theorem. These traits are similar to those of Levy walks. It is conjectured that the truncation, which makes the mobility deviate from pure Levy walks, comes from geographical constraints including walk boundary, physical obstructions and traffic. None of commonly used mobility models for mobile networks captures these properties. Based on these findings, we construct a simple Levy walk mobility model which is versatile enough in emulating diverse statistical patterns of human walks observed in our traces. The model is also used to recreate similar power-law inter-contact time distributions observed in previous human mobility studies. Our network simulation indicates that the Levy walk features are important in characterizing the performance of mobile network routing performance.

Smart Windows: Electro-, Thermo-, Mechano-, Photochromics, and Beyond

Abstract: Smart window refers to the on-demand window that can dynamically modulate light transmittance. It is recognized as a promising technology to economize building energy A smart window that dynamically modulates light transmittance is crucial for building energy efficiently, and promising for on-demand optical devices. The rapid development of technology brings out different categories that have fundamentally different transmittance modulation mechanisms, including the electro-, thermo-, mechano-, and photochromic smart windows. In this review, recent progress in smart windows of each category is overviewed. The strategies for each smart window are outlined with particular focus on functional materials, device design, and performance enhancement. The advantages and disadvantages of each category are summarized, followed by a discussion of emerging technologies such as dual stimuli triggered smart window and integrated devices toward multifunctionality. These multifunctional devices combine smart window technology with, for example, solar cells, triboelectric nanogenerators, actuators, energy storage devices, and electrothermal devices. Lastly, a perspective is provided on the future development of smart windows. Smart Windows