X-ray Flux and Pulse Frequency Changes of Three High Mass X-ray Binary Pulsars: Vela X-1, GX 301-2 and OAO 1657-415

Using archival BATSE (Burst and Transient Source Experiment) 20-60 keV band X-ray flux and pulse frequency time series, we look for correlations between torque, luminosity and specific angular momentum for three high mass X-ray binary pulsars Vela X-1, GX 301-2 and OAO 1657-415. Our results show that there is no correlation between pulse frequency derivative and flux which may be an indication of the absence of stable prograde accretion disk. From the strong correlation of specific angular momentum and torque, we conclude that the accretion geometry changes continuously as suggested by the hydrodynamic simulations(Blondin et al. 1990).Comment: 14 pages, 9 figures, accepted for publication in Astronomy and Astrophysic

Compressive forces causing rod buckling in sucker rod pumps and using sinker bars to prevent buckling

Sucker rod pumps has been the most commonly used pumps in the petroleum industry. Therefore, many studies associated with sucker rods focuses on maximizing the rod life. Rod buckling is a leading problem which causes concentrated wear on tubing wall, immediate failure in rod strings, and shortens fatigue life of the string. This study fundamentally consists of a review of the literature on compressive forces causing rod buckling in sucker rod pumps and using sinker bars to prevent buckling. The study initially addresses defining rod buckling, and then continues with the studies on analyzing the static forces acting near pump in the literature. Subsequently, the critical loads causing rod buckling, and the various approximations to estimate these critical loads are discussed. Then, the comparisons of the measured and calculated critical loads in the literature are presented. Next, the two of the most commonly experienced buckling types in the sucker pumps, sinusoidal buckling and helical buckling, are discussed. An example study on developing a model to estimate compressive forces acting on the pump plunger is reviewed to illustrate the importance of the parameters, such as surface roughness of pump, valve diameter, and pump geometry. Lastly, using sinker bar which is the most practiced method in the industry to prevent rod buckling is extensively discussed and demonstrated.Petroleum and Geosystems Engineerin

Spatio-Temporal Saliency Networks for Dynamic Saliency Prediction

Computational saliency models for still images have gained significant popularity in recent years. Saliency prediction from videos, on the other hand, has received relatively little interest from the community. Motivated by this, in this work, we study the use of deep learning for dynamic saliency prediction and propose the so-called spatio-temporal saliency networks. The key to our models is the architecture of two-stream networks where we investigate different fusion mechanisms to integrate spatial and temporal information. We evaluate our models on the DIEM and UCF-Sports datasets and present highly competitive results against the existing state-of-the-art models. We also carry out some experiments on a number of still images from the MIT300 dataset by exploiting the optical flow maps predicted from these images. Our results show that considering inherent motion information in this way can be helpful for static saliency estimation

Balancing Sparsity and Rank Constraints in Quadratic Basis Pursuit

We investigate the methods that simultaneously enforce sparsity and low-rank structure in a matrix as often employed for sparse phase retrieval problems or phase calibration problems in compressive sensing. We propose a new approach for analyzing the trade off between the sparsity and low rank constraints in these approaches which not only helps to provide guidelines to adjust the weights between the aforementioned constraints, but also enables new simulation strategies for evaluating performance. We then provide simulation results for phase retrieval and phase calibration cases both to demonstrate the consistency of the proposed method with other approaches and to evaluate the change of performance with different weights for the sparsity and low rank structure constraints

Convex Optimization Approaches for Blind Sensor Calibration using Sparsity

We investigate a compressive sensing framework in which the sensors introduce a distortion to the measurements in the form of unknown gains. We focus on blind calibration, using measures performed on multiple unknown (but sparse) signals and formulate the joint recovery of the gains and the sparse signals as a convex optimization problem. We divide this problem in 3 subproblems with different conditions on the gains, specifially (i) gains with different amplitude and the same phase, (ii) gains with the same amplitude and different phase and (iii) gains with different amplitude and phase. In order to solve the first case, we propose an extension to the basis pursuit optimization which can estimate the unknown gains along with the unknown sparse signals. For the second case, we formulate a quadratic approach that eliminates the unknown phase shifts and retrieves the unknown sparse signals. An alternative form of this approach is also formulated to reduce complexity and memory requirements and provide scalability with respect to the number of input signals. Finally for the third case, we propose a formulation that combines the earlier two approaches to solve the problem. The performance of the proposed algorithms is investigated extensively through numerical simulations, which demonstrates that simultaneous signal recovery and calibration is possible with convex methods when sufficiently many (unknown, but sparse) calibrating signals are provided

Modeling emergency management data by UML as an extension of geographic data sharing model: AST approach

Applying GIS functionality provides a powerful decision support in various application areas and the basis to integrate policies directed to citizens, business, and governments. The focus is changing toward integrating these functions to find optimal solutions to complex problems. As an integral part of this approach, geographic data sharing model for Turkey were developed as a new approach that enables using the data corporately and effectively. General features of this model are object-oriented model, based on ISO/TC211 standards and INSPIRE Data Specifications, describing nationwide unique object identifiers, and defining a mechanism to manage object changes through time. The model is fully described with Unified Modeling Language (UML) class diagram. This can be a starting point for geographic data providers in Turkey to create sector models like Emergency Management that has importance because of the increasing number of natural and man-made disasters. In emergency management, this sector model can provide the most appropriate data to many "Actors" that behave as emergency response organizations such as fire and medical departments. Actors work in "Sectors" such as fire department and urban security. Each sector is responsible for "Activities" such as traffic control, fighting dire, emission, and so on. "Tasks" such as registering incident, fire response, and evacuating area are performed by actors and part of activity. These tasks produce information for emergency response and require information based on the base data model. By this way, geographic data models of emergency response are designed and discussed with "Actor-Sector-Activity-Task" classes as an extension of the base model with some cases from Turkey

Doctoral research on cadastral development

The multitude of rights in land and the recording of these rights are addressed by a number of studies, yet a recognized paradigm for such studies seems missing. Rights in land are recorded and managed through either cadastral systems or land administration systems depending on the legal system of the countries concerned. The cadastre, however, is the core of both systems as it provides for systematic and official descriptions of land parcels or real property units. The research mentioned often has a development perspective, and in this article we will motivate the introduction of the research domain of cadastral development. This research is multi-disciplinary and draws on elements of theories and methodologies from the natural, the social, the behavioral, and the formal sciences. During the last decade or so, doctoral dissertations have come to constitute a substantial part of this research effort. The article focuses on the methodological aspect of doctoral research by analyzing ten doctoral dissertations. Our analysis is based on a taxonomy of methodological elements and aims at identifying commonalities and differences among the dissertations in the use of concepts and methods. Having completed the main analysis, we invited the authors of the dissertations to comment upon our analysis of their work and the developed taxonomy. The responses corroborate the view that the taxonomy could be used for further analyses and provide for a framework for further doctoral research. The article concludes with a call for a shared terminology and a shared set of concepts which may contribute to further theory building within the cadastral domain. © 2008 Elsevier Ltd. All rights reserved

How did medicaid expansions affect labor supply and welfare enrollment? Evidence from the early 2000s

In the early 2000s, Arizona, Maine, New Mexico, New York, Oregon, and Vermont expanded Medicaid to cover more low-income individuals, primarily childless adults. This change provides the researcher with an opportunity to analyze the effects of these expansions on labor supply and welfare enrollment. I use a large data set of 176 counties over 7 years, including 3 years of pre-expansion period, 1 year of implementation year, and 3 years of post-expansion period. Using a difference-in-differences approach, I find the most-affected counties had a 1.4 percentage-point more decline in labor force participation rate in comparison to other counties. Furthermore, I observe a 0.32 h decrease in average weekly hours and a 1.1 % increase in average weekly wages. This indicates labor supply was affected more than labor demand. I also observe a 0.49 % increase in Supplemental Nutrition Assistance Program (SNAP) enrollment after the Medicaid expansions. These results are robust to an alternative identification of the most-affected counties, inclusion of counties from comparison states, limiting the control group to only high-poverty counties from comparison states, exclusion of county-specific time trends, and different configuration of clustered errors. My findings provide early insights on the potential effects of new Medicaid expansions of the Affordable Care Act (ACA), since 82 % of those newly eligible are expected to be childless adults

Forecasting The Exchange Rate Series With Ann: The Case Of Turkey

As it is possible to model both linear and nonlinear structures in time series by using Artificial Neural Network (ANN), it is suitable to apply this method to the chaotic series having nonlinear component. Therefore, in this study, we propose to employ ANN method for high volatility Turkish TL/US dollar exchange rate series and the results show that ANN method has the best forecasting accuracy with respect to time series models, such as seasonal ARIMA and ARCH models. The suggestions about the details of the usage of ANN method are also made for the exchange rate of Turkey.Activation function, ARIMA, ARCH, Artificial neural network, Chaotic series, Exchange rate, Forecasting, Time series

Towards printable robotics: Origami-inspired planar fabrication of three-dimensional mechanisms

This work presents a technique which allows the application of 2-D fabrication methods to build 3-D robotic systems. The ability to print robots introduces a fast and low-cost fabrication method to modern, real-world robotic applications. To this end, we employ laser-engraved origami patterns to build a new class of robotic systems for mobility and manipulation. Origami is suitable for printable robotics as it uses only a flat sheet as the base structure for building complicated functional shapes, which can be utilized as robot bodies. An arbitrarily complex folding pattern can be used to yield an array of functionalities, in the form of actuated hinges or active spring elements. For actuation, we use compact NiTi coil actuators placed on the body to move parts of the structure on-demand. We demonstrate, as a proof-of-concept case study, the end-to-end fabrication and assembly of a simple mobile robot that can undergo worm-like peristaltic locomotion.United States. Defense Advanced Research Projects Agency (Grant W911NF-08-C-0060)United States. Defense Advanced Research Projects Agency (Grant W911NF-08-1-0228