Low Complexity Noncoherent Iterative Detector for Continuous Phase Modulation Systems

This paper focuses on the noncoherent iterative detection of continuous phase modulation. A class of simplified receivers based on Principal-Component-Analysis (PCA) and Exponential-Window (EW) is developed. The proposed receiver is evaluated in terms of minimum achievable Euclidean distance, simulated bit error rate and achievable capacity. The performance of the proposed receiver is discussed in the context of mismatched receiver and the equivalent Euclidean distance is derived. Analysis and numerical results reveal that the proposed algorithm can approach the coherent performance and outperforms existing algorithm in terms of complexity and performance. It is shown that the proposed receiver can significantly reduce the detection complexity while the performance is comparable with existing algorithms

Development of framework for predicting water production from oil and gas wells in Wattenberg field, Colorado

2012 Fall.Includes bibliographical references.Water issues in the oil and gas industry have drawn attention from various stakeholders including the public, industry and environmental groups. With the increasing demand for energy, the number of oil and gas wells has increased greatly providing 60% of the energy in the United States. Besides the large volume of fresh water required for drilling and hydraulic fracturing, wastewater from the well can also lead to serious problems. The current approach for managing wastewater from oil and gas fields is deep well injection or evaporation both of which can potentially cause environmental issues. One of the best strategies to solve water issues from oil and gas operations is to reuse wastewater as drilling and fracturing water so the volume of fresh water required and wastewater disposed can be reduced. Information on both water quantity and quality are required when designing wastewater reuse treatment facilities. This study provides a framework for understanding water production trends from oil and gas wells in the Wattenberg field in Northern Colorado by analyzing historical data from Noble Energy Inc. The Arps equations were chosen for modeling water production from oil and gas wells. After studying 1,677 vertical and 32 horizontal wells in Wattenberg field, an exponential decline function was applied to model the produced water production of all the wells and the frac flowback water of horizontal wells. An Excel based 30-year water production prediction tool was developed based on the two protocols developed for vertical and horizontal wells in the Wattenberg field. Three case studies of different subsets of oil and gas wells were examined to illustrate the function of the tool. In addition, a comparison of exponential and harmonic functions was made in the third case study, and a significant difference was observed. The harmonic decline function predicts a less aggressive decline resulting in higher production volumes. It was concluded that in the absence of long term production data, the harmonic decline function should be used since the exponential decline function may underestimate the volume of produced water

ESSAYS IN FAMILY ECONOMICS

The first chapter examines the effect of the number of years children spend living with a single-parent family instead of a two-parent family on children\u27s completed schooling, based on a sample of children from the PSID. To deal with the endogeneity of mothers\u27 family structure decisions, I exploit the variation across states and over time in unilateral divorce laws, unmarried fertility ratios, welfare rules, earned income tax credit rates, and labor market conditions that generate plausibly exogenous changes in mothers\u27 family structure choices. I construct a set of extensive measures for these contextual variables and use them as instruments to estimate a child\u27s human capital production function. Instrumental variable estimation indicates that one additional year spent in a single-parent family during childhood (ages 0-15) can cause a loss of 0.145 years in schooling. This result implies that the differences in family structure experiences over the early life course between white and nonwhite children can explain roughly 76% of the gap in educational attainment between the two groups. On the other hand, ordinary least-squares estimation only suggests 13%. Children born to unmarried parents may receive lower human capital investments in youth, and therefore may be less likely to finish high school or to attend college. The second chapter explores these effects empirically using state level data over the period 1940-2000. We find that a steady-state increase in unmarried fertility ratio of 100 per 1,000 child births could lead to a 4.6 percent drop in high school graduation rate and a steady-state 4.2 percent decline in secondary school enrollment in the long-run. This result is important since Heckman and Lafontain (2010) found that since the late 1960s the high school graduation rate has fallen by 4-5 percentage points, despite the growing wage differentials between high school graduates and dropouts. Our analysis implies that the rise in unmarried fertility predicts a ceteris paribus drop in high school graduation rate of about 6.6% in the same time period, thus provides an important explanation for the dropout problem in recent decades.. Moreover, our results indicate a very weak link between abortion and child education, in contrast to the strong effect of abortion on crime documented in the literature

Identification of components and substrates of Snf1-related kinase 1 (SnRK1) complexes in <em>Arabidopsis thaliana</em>

Similarly to yeast Sucrose nonfermenting 1 (Snf1) and animal AMP-activated protein kinases (AMPKs), plant Snf1-related (SnRK1) kinases play a central role in the regulation of cellular energy homeostasis and responses to carbon source availability. Members of the Snf1/SnRK1/AMPK family are differentially activated by carbon source depletion and increasing AMP/ATP ratio to confer down-regulation of energy consuming anabolic pathways and parallel activation of energy producing processes by phosphorylation of key metabolic enzymes and transcription factors. Inhibition of photosynthetic CO2 fixation and ATP production stimulates plant SnRK1 activation in leaves, which provide sucrose as main transported sugar for developing sink organs. Sensing of sucrose availability by conversion of its metabolic products to trehalose-6-phosphate (T6P) is reported to inhibit SnRK1 through a yet unknown protein factor. As Snf1 and AMPKs, Arabidopsis SnRK1 enzymes form trimeric complexes with activating γ/SNF4 and substrate targeting β1/2/3-subunits. SnRK1 activity is stimulated by T-loop phosphorylation of catalytic α-subunits AKIN10/11 by upstream activating kinases and inhibited through dephosphorylation by PP2C protein phosphatases acting in ABA/sugar signaling. Our current knowledge on plant SnRK1 kinases is largely based on protein-protein interaction assays in heterologous systems, and transcriptomics and phosphoproteomics studies using antisense inhibition and overexpression of SnRK1 catalytic subunits in leaf protoplasts and seedlings carrying various mutations in metabolic and hormonal pathways. A major goal of this Ph.D. work was to use precisely modified native gene constructs for expression of SnRK1 subunits in fusion with suitable tags, such as green and red fluorescent proteins (GFP and mCherry) in plants, and exploit this technology for purification of SnRK1 complexes and identification of their interacting partners. By enlarging the ATP-binding pocket of SnRK1α1 subunit AKIN10, an analog-sensitive AS-kinase carrying a combined affinity tag (GFPPIPL) was constructed by recombineering-based site-directed mutagenesis and expressed in plants. Unlike other kinases in Arabidopsis, the AS-AKIN10 kinase can catalyze phosphorylation of substrates with bulky N6-substituted thioATP derivatives, which can be specifically detected, enriched and identified by mass spectrometry. Our study demonstrates that exchange of the phosphorylated T-loop Thr175 residue of AKIN10 to A and D/E residues results only in partial inactivation and limited stimulation of substrate phosphorylation activity of SnRK1 in vitro and, upon ectopic expression of cDNA constructs by a CaMV35S promoter in vivo, respectively. Ectopic expression of wild type and T-loop mutant versions of AKIN10 resulted only in minor developmental changes, including earlier flowering on short day, and enhanced root and hypocotyl elongation in the case of T175D T-loop AKIN10 derivative. Expression of AKIN10-GFP/PIPL and SNF4-YFP constructs by native genes provided suitable materials for affinity purification of SnRK1 complexes and identification of their interacting partners by mass spectrometry. In addition to previously described two-hybrid interacting partners, such as the HSPRO2 and DUF581 domain proteins, these studies confirmed reciprocal co-immunoprecipitation and association of class II trehalose synthase/ phosphatase (TPS) enzymes with SnRK1. Dimerization of trimeric SnRK1 enzymes was detected in cytoplasmic complexes. Association of SnRK1 with TPS partners, such as TPS8, was found to confer UDP-glucose and T6P mediated inhibition of SnRK1. This indicated that class II TPS enzymes might serve as metabolic sensors, which negatively regulate SnRK1 in response to the availability of sucrose-derived metabolic signals. However, using a nuclear protein purification approach optimized for the isolation of NTC spliceosome-activating complex and associated spliceosome components, we failed to identify novel interacting partners of SnRK1. Optimization of in situ kinase reactions in isolated nuclei and nuclear extracts, as well as enrichment of thiophosphorylated substrates of the analog-sensitive AS-AKIN10 kinase, nevertheless resulted in the identification of several novel candidate SnRK1 substrates. One of these, the nuclear NAP57/CBF5/DYSKERIN pseudouridine synthase involved in the regulation of telomere length and ribosome biogenesis was found to be phosphorylated in its catalytic domain by SnRK1. Further analysis of AS-kinase substrates and components of nuclear kinase complexes is expected to provide deeper insight into transcription targets and regulatory roles of plant SnRK1

Vertex-deleted subgraphs and regular factors from regular graph

Let $k$, $m$ and $r$ be three integers such that $2\leq k\leq m\leq r$. Let $G$ be a $2r$-regular, $2m$-edge-connected graph of odd order. We obtain some sufficient conditions, which guarantee $G-v$ contains a $k$-factor for all $v\in V(G)$