271 research outputs found
RESPONSE OF CANADIAN ROCKIES GLACIER HYDROLOGY TO CHANGING CLIMATE
This thesis investigates the impact of snow and glaciers in mountain hydrology under changing climate conditions and glacier configurations in the Canadian Rockies, where a warming climate and glacier retreat cause concern about changes in mountain hydrology for water availability downstream. The general objectives of the study are (1) to model snow and glacier ablation and accumulation dynamics, (2) to determine how they influence high mountain hydrology, and (3) to improve hydrological modeling capacity in high mountain cold regions. The specific objectives are: (1) to develop a new model to estimate shortwave irradiance from temperature and humidity observations; (2) to include snow redistribution and the full energy and mass budget in a glacier hydrological modelling platform; (3) to apply the model to diagnose the individual and combined impacts of changes in climate and glacier mass on headwater hydrology. The thesis has four major parts. First, it describes the methodology used to produce meteorological data to force a hydrological model for the Peyto Glacier Research Basin (PGRB) in the Canadian Rockies. Second, it develops a new approach for estimating shortwave irradiance based on temperature and humidity observations that is suitable for snow and ice melt calculations for mountains and other cold regions around the world. Observations from thirty mostly mountain sites in South and North America, Europe and the Himalayas were used to evaluate existing algorithms and reanalysis products. The new algorithm, coupled to an existing extraterrestrial shortwave irradiance model, permitted more accurate estimation of shortwave irradiance from standard meteorological observations than was previously possible. The globally available reanalysis products also offer the potential for application to large-scale hydrological models. Third, the thesis develops a novel glacier hydrology model, developed within the Cold Regions Hydrological Model platform (CRHM), which is a physically based, integrated model capable of simulating the hydrology of both ice-covered and ice-free areas within a mountain basin. Fourth, the thesis focuses on diagnosing the impacts of climate change and changing glacier configuration on mountain headwater hydrology. The modelling results reveal that glacier retreat and ablation are due to the joint effect of a warming climate and an increase in ice exposure, which increase both seasonal melt and runoff. Increased streamflow is due to climate warming. However, the increases in melt and runoff are reduced somewhat by the reduction in glacial area. Such a modelling approach is important for diagnosing the hydrological responses from a glacierized basin in the context of climate change and variability and change in glacier configuration
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FINANCIALIZATION OF THE COMMODITIES FUTURES MARKETS AND ITS EFFECTS ON PRICES
After declining for almost three decades, the food price index of the Food and Agricultural Organization (FAO) rose by 90 percent between January 2002 and June 2008. Besides the magnitude, the rise in prices was remarkable for its breadth, affecting a broad range of commodities including agricultural (wheat, corn, soybeans, cocoa, coffee), energy (crude oil, gasoline), and metals (copper, aluminum). According to the US Department of Agriculture, this price spike was responsible for increasing the number of malnourished people by 80 million. These dramatic developments in prices coincided with a rapid inflow of investment into the commodities futures market -- the number of open contracts between 2001 and June 2008 increased by more than six-fold, from around 6 million to 37 million. The new investment was primarily driven by portfolio diversification motives of a new class of traders who were neither producers nor direct consumers of the underlying commodities.
This dissertation examines the potential causal links between this financialization of the commodities futures market and the 2008 global spike in food prices and other commodities. The dissertation consists of three major chapters. The second chapter analyses the relationship between spot and futures markets for a range of commodities. The third and fourth chapters seek to understand the role of financialization in causing the 2008 price developments. Chapter 3 explores commodity markets individually, studying the correlation between the inflow of liquidity and price changes. Chapter 4 studies the issue at a more macro level by investigating if the inflow of investment can explain the increase in comovement of prices between unrelated commodities.
My results show that i) for many commodities, prices are determined in the futures markets, and ii) financialization of the futures market was an important factor in causing the 2008 price rises for a range of commodities. These results underscore the increasingly important role of financial motive, financial markets, and financial instruments in the operation of the commodities market. The findings are especially relevant with respect to debates as to the relative efficiency of financial markets and the need to regulate them
Experimental validation of a smart-bias active magnetic bearing controller
Active magnetic bearings (AMBs) are being increasingly employed in the aerospace industry in a variety of devices including compressors, turbines, pumps, and flywheels. One application of great interest to future space missions is the Integrated Power and Attitude Control System (IPACS). The IPACS consists of an arrangement of flywheels that integrates the energy storage and attitude control functions into a single system; thereby, reducing the spacecraft mass, volume, launching cost, and maintenance. Like any energy storage system, flywheels need to be operated with low power losses. AMBs are ideally suited for flywheels because they eliminate mechanical losses (friction). Nevertheless, AMBs are subject to electrical losses, which are proportional to the bias flux. We recently developed an innovative solution to the problem of AMB control with reduced electrical power losses. The controller incorporates a smart, time-varying bias flux that reduces power losses without affecting the rotor stabilization. The novelty of the smart-bias controller strongly motivated the pursuit of the next step in this research – an experimental validation. To that end, the objectives of this project were: · Design and build an experimental AMB test rig. · Conduct tests to validate the smart-bias controller and its power-loss reduction mechanism in comparison to a standard constant-bias AMB controller. The experimental results show that the smart-bias controller clearly reduces the electrical power losses and energy dissipation of the AMB system in comparison to the constant-bias approach, without significantly affecting the stabilization performance. These results confirm, in a qualitative manner, the theoretical and numerical results obtained earlier
Economic Coping Mechanisms In Response To Household Health Shocks In Kagera, Tanzania: 1991-2004
ABSTRACT
Background: Chronic and acute illnesses pose substantial economic burden on households due to explicit health expenses and implicit costs engendered by decreased productivity and increased time allocation to care provision. This study examined economic coping mechanisms employed by households to respond to health shocks represented by chronic and acute morbidities.
Methods: Data from Kagera Health and Development Survey (1991-2004) were utilized to examine household health status and economic coping. Pooled OLS regression models were used to analyze the association between household health status and economic burden and coping mechanisms controlling for household size, mean age, income, and characteristics of household head. Household health status was categorized as chronic, acute, or healthy, economic burden was characterized by health expenditures, and coping variables examined included assets, transfers, and debt. Fixed effects regression models were employed to assess variations in household economic indicators and coping strategies corresponding to changes in health status over time.
Results: Pooled regression analysis did not indicate significant associations between health status and economic burden and coping strategies. Fixed effects model revealed that entry into chronic and acute status was significantly associated with increases in health expenditures (p value 0.01). The marginal propensity to spend on health expenses given additional transfers was 0.22 for acute households (p value 0.01).
Conclusion: Although health status overall did not significantly explain economic coping, developing acute and chronic illnesses was associated with larger health expenditures with chronic status being associated with the biggest increase. Transfers played a significant role in funding health expenses for acute households, and chronic households appear to have relied on self-insurance
Effective Linear-Time Feature Selection
The classification learning task requires selection of a subset of features to represent patterns
to be classified. This is because the performance of the classifier and the cost of
classification are sensitive to the choice of the features used to construct the classifier.
Exhaustive search is impractical since it searches every possible combination of features.
The runtime of heuristic and random searches are better but the problem still persists
when dealing with high-dimensional datasets.
We investigate a heuristic, forward, wrapper-based approach, called Linear Sequential
Selection, which limits the search space at each iteration of the feature selection process.
We introduce randomization in the search space. The algorithm is called Randomized
Linear Sequential Selection. Our experiments demonstrate that both methods are faster,
find smaller subsets and can even increase the classification accuracy.
We also explore the idea of ensemble learning. We have proposed two ensemble creation
methods, Feature Selection Ensemble and Random Feature Ensemble. Both methods apply
a feature selection algorithm to create individual classifiers of the ensemble. Our
experiments have shown that both methods work well with high-dimensional data
Performance Evaluation of Video Streaming in an Infrastructure Mesh Based Vehicle Network
Most next-generation wireless networks are expected to support video stream- ing which constitutes the bulk of traffic on the Internet. This thesis evaluates the performance of video streaming in a vehicle network with an infrastructure wireless mesh network (WMN) backhaul. Several studies have investigated video quality per- formance primarily in single hop wireless networks and static WMNs. This thesis is based on those studies and conducts the study in relation to a network where the multi-hop features of the mesh network and mobility of the streaming clients may have substantial impact on the perceived video quality in the network. The study assumes a previously proposed vehicle network architecture con- sisting of an infrastructure WMN that serves as the mesh backhaul [2, 3]. A number of mesh routers (MRs) form the mesh backhaul using one of their two IEEE 802.11g radios whereas the other radio is used to communicate with the fast moving mesh clients (MCs). Selective MRs called mesh gateways (MGs) are connected to a wired network (e.g., the Internet, hereafter referred to as the core network) via a point-to- point link and provide gateway connectivity to the rest of the network. A server on the core network acts as a video server and streams individual video streams to the fast moving MCs. Upon deployment, network discovery occurs and segregates the network into a number of separate routing zones with each routing zone consisting of a single MG and all the MRs that use the MG as their gateway. A minimum-hop based routing protocol is used to enable seamless handover of MCs from one MR to another within a single zone. Simulation studies in this thesis inspects the network and video streaming performance within a single routing zone, assuming the handoff and inter-zone routing being taken care of by the routing protocol and only focus on the intra-zone packet forwarding and scheduling impacts. Hence, this study does not address cases where MCs move from one routing zone to another routing zone in the mobile network. In the first part of the study, we evaluate the performance of video streaming in the described network by studying performance metrics across different layers of the protocol stack. The number of video flows that can be supported by the network is experimentally determined for each scenario. In the second part, the thesis studies controllable network and protocol parameters\u27 ability to improve the network and video quality performance. Simulations are run in an integrated framework that includes network-simulator ns-2, NS-MIRACLE, and Evalvid
Tiarrah Computing: The Next Generation of Computing
The evolution of Internet of Things (IoT) brought about several challenges for the existing Hardware, Network and Application development. Some of these are handling real-time streaming and batch bigdata, real- time event handling, dynamic cluster resource allocation for computation, Wired and Wireless Network of Things etc. In order to combat these technicalities, many new technologies and strategies are being developed. Tiarrah Computing comes up with integration the concept of Cloud Computing, Fog Computing and Edge Computing. The main objectives of Tiarrah Computing are to decouple application deployment and achieve High Performance, Flexible Application Development, High Availability, Ease of Development, Ease of Maintenances etc. Tiarrah Computing focus on using the existing opensource technologies to overcome the challenges that evolve along with IoT. This paper gives you overview of the technologies and design your application as well as elaborate how to overcome most of existing challenge
Association studies of exome sequencing data of lung cancer patients undergoing gemcitabine/carboplatin chemotherapy with myelosuppression toxicity
Chemotherapeutic drugs such as carboplatin/gemcitabine administerd to non small cell lung cancer (NSCLC) patients frequently induce myelosuppression toxicity potentially leading to reduction or removal of drugs. We set out to identify the genetic variants associated with toxicity induced myelosuppression by whole exome sequencing (WES) 216 NSCLC patients and associating biallelic variants with different quantitative and qualitative measurements of myelosuppression phenotypes.
WES identified on average 29834 variants in each patient. Biallelic variants from combined patients genotype were associated with each myelosupression phenotype - Thrombocytopenia (TPK), Leukopenia (LPK) and Neutropenia (NPK) using quantitative Log-transformed (LN) and Empirical normal quantile transformation (ENQT) phenotypes and qualitative high/low toxicity study design in linear and logistic regression methods. Additionally, gene-based SKATO tests were performed for transformed quantitative phenotypes to investigate enrichment of rare and common variants.
Due to sample size limitation, none of the variants reached multiple corrected Bonferroni significant or FDR-BH p - values <1.00 X 10-3 . However, variants with p-value in each study design were evaluated for high toxicity. We found five, one and two variants for TPK, LPK and NPK respectively associated in all quantitative and qualitative single variant association study. Furthermore, single variant rs4808 in CAPZA2 and rs8018462 in SLC7A7 genes were identified by Gene-based SKATO test for TPK and LPK phenotypes. This results could implicate association of CAPZA2 and SLC7A7 to TPK and LPK myleosupression. However, validation and replication of the variants and genes needs to be further studied in an independent studies
Quantity-based cost forecasting system for street construction projects
Construction projects typically are not withdrawn after going into the competitive bidding process. The decision of contracting authorities regarding which projects will proceed to the bidding stage depends, in part, upon the early estimates of probable cost. Efforts are made to make this estimate as realistic as possible. Irrespective of the estimate of probable cost, the actual project cost is established by the amount of the winning bid.
This study analyzed historical bid data of street construction projects undertaken by the Public Works Department, Clark County, Nevada, from 1991 through 2006. The focus of this study was on utilizing statistical models to develop improved methodologies for predicting bid-item unit pricing and reducing variances resulting in large discrepancies between project estimates and actual bid-award amounts. A regression model was developed to improve predictions of actual project costs based on calculations using all bid items. The resulting models were incorporated into a database and integrated into a computer software program to facilitate the predictive process for future projects
Utilization of Lapsi seed stone (choerospondias axillaris) as source of activated charcoal for removal of arsenic
People inhabited in Terai region of Nepal use ground water as the main source of drinking water that are contaminated with arsenic at concentration level higher than guide line value set by WHO. The arsenic in the ground water is originated from the dissolution of naturally occurring arsenic containing minerals. Nepal, being a poor country, cannot afford to adopt costly and sophisticated technology to remove arsenic. Adsorptive removal of arsenic utilizing the activated charcoal prepared from the locally available Lapsi (chorespondias axillaris, Roxb) seed stone is presented. Tons of Lapsi seed stones are generated as waste which can be carbonized to activated charcoal. The adsorption capacity for arsenic is quite low for raw charcoal but activation followed by iron impregnation greatly enhances it. The low cost activated charcoal prepared from locally available Lapsi seed stones can be used in community level at point- of- use treatment for arsenic contaminated ground water of Terai region of Nepal
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