Information-theoretic lower bounds on the oracle complexity of stochastic convex optimization

Relative to the large literature on upper bounds on complexity of convex optimization, lesser attention has been paid to the fundamental hardness of these problems. Given the extensive use of convex optimization in machine learning and statistics, gaining an understanding of these complexity-theoretic issues is important. In this paper, we study the complexity of stochastic convex optimization in an oracle model of computation. We improve upon known results and obtain tight minimax complexity estimates for various function classes

Design and Implementation of I2C BUS Protocol on Xilinx FPGA

The focal point of this research is to design and implement the Inter-Integrated Circuit (I2C) protocol with different types of features such as combined message, addressing mode, different data pattern, different start address, clock frequency, and type of mode between the FPGA and Test card. By using test card, signal integrity issue will be able to reduce as test card will be able to replicate the actual device. I2C IP is also able to reduce the cost and complexity issue as it consists of two signal. All of this features will able to randomize and run for long hours. The field-programmable gate array (FPGA) will act as master and test card as slave. As the design architecture consists of master and slave, the master will generates a START condition and at this condition the serial data (SDA) will have a transaction between high level to low level and serial clock (SCL) will remain high. Besides that, Master will also generate STOP condition. At STOP condition, SCL is HIGH and SDA will have a transaction from LOW to HIGH. Additionally, there are a few type of messaging mode such as read transaction, write transaction, write-read transaction and read-write transaction. All this messaging mode will have its own protocol. On the other hand, master also transfers and received data to or from slave devices by different addressing mode. The addressing mode that is implemented are 7 bit addressing mode and 10 bit addressing mode. This thesis is also concerned by randomizing the data byte send and start address. The data send, read and write particularly these operations are carried out and stimulate by capturing signal using logic analyzer. The signal is then examined and compared with the actual I2C protocol format. A stress test is also done by andomizing all the features and running for long hours which is 4 hours. This stress test is carried to stress the IP and make sure the IP is health

Studies on mechanical behavior of glass epoxy composites with induced defects and correlations with NDT characterization parameters

Degradation in mechanical properties (compression, flexural and ILS) of glass epoxy composite laminates with induced defects (simulating delaminations) was studied. The defects were characterized by using the A-scan ultrasonic pulse-echo technique. The two A-scan parameters, viz. the back wall echo amplitude and time of flight, were followed respectively, as functions of the defect size (diameter) and its location in the laminate thickness. The mechanical properties of laminates were evaluated destructively for different defect sizes and locations. An attempt has been made to express the mechanical properties in terms of the two NDT scan parameters characterizing the defects and empirical equations presente

Phonon Anomalies, Orbital-Ordering and Electronic Raman Scattering in iron-pnictide Ca(Fe0.97Co0.03)2As2: Temperature-dependent Raman Study

We report inelastic light scattering studies on Ca(Fe0.97Co0.03)2As2 in a wide spectral range of 120-5200 cm-1 from 5K to 300K, covering the tetragonal to orthorhombic structural transition as well as magnetic transition at Tsm ~ 160K. The mode frequencies of two first-order Raman modes B1g and Eg, both involving displacement of Fe atoms, show sharp increase below Tsm. Concomitantly, the linewidths of all the first-order Raman modes show anomalous broadening below Tsm, attributed to strong spin-phonon coupling. The high frequency modes observed between 400-1200 cm-1 are attributed to the electronic Raman scattering involving the crystal field levels of d-orbitals of Fe2+. The splitting between xz and yz d-orbital levels is shown to be ~ 25 meV which increases as temperature decreases below Tsm. A broad Raman band observed at ~ 3200 cm-1 is assigned to two-magnon excitation of the itinerant Fe 3d antiferromagnet.Comment: Accepted for Publication in JPC

Financial Time Series Forecasting using Agent Based Models in Equity and FX Markets

We investigate the application of machine learning Agent Based Modelling (ABM) techniques to model and forecast various financial markets including Foreign Exchange and Equities, especially models that could reproduce the time-series properties of the financial variables. We model the economy by considering non-equilibrium economics. We adopt the features that are required for modelling non-equilibrium economics using ABMs and replicate the non-equilibrium nature of the financial markets by considering a set of bounded rational heterogeneous agents, with different strategies that are ranked according to their performance in the market. We consider markets where there are different agents interacting among themselves and forming some sort of patterns. For example, the patterns are equity prices or exchange rates. While the agents have been interacting in the artificial market, the generated patterns (price dynamics) they co-produce would match with the real financial time-series. In order to get the best fit to the real market, we need to search for the best set of artificial heterogeneous agents that represents the underlying market. Evolutionary computing techniques are used in order to search for a suitable set of agent configuration in the market. We verify the forecasting performance of the artificial markets by comparing that with the real financial market by conducting out-of-sample tests

Proton pump inhibitors are associated with increased risk of development of chronic kidney disease

Background Acute interstitial nephritis secondary to proton pump inhibitors (PPIs) frequently goes undiagnosed due to its subacute clinical presentation, which may later present as chronic kidney disease (CKD). We investigated the association of PPI use with the development of CKD and death. Methods Two separate retrospective case–control study designs were employed with a prospective logistic regression analysis of data to evaluate the association of development of CKD and death with PPI use. The population included 99,269 patients who were seen in primary care VISN2 clinics from 4/2001 until 4/2008. For evaluation of the CKD outcome, 22,807 with preexisting CKD at the first observation in Veterans Affairs Health Care Upstate New York (VISN2) network data system were excluded. Data obtained included use of PPI (Yes/No), demographics, laboratory data, pre-PPI comorbidity variables. Results A total of 19,311/76,462 patients developed CKD. Of those who developed CKD 24.4 % were on PPI. Patients receiving PPI were less likely to have vascular disease, COPD, cancer and diabetes. Of the total of 99,269 patients analyzed for mortality outcome, 11,758 died. A prospective logistic analysis of case–control data showed higher odds for development of CKD (OR 1.10 95 % CI 1.05–1.16) and mortality (OR 1.76, 95 % CI 1.67–1.84) among patients taking PPIs versus those not on PPIs. Conclusions Use of proton pump inhibitors is associated with increased risk of development of CKD and death. With the large number of patients being treated with proton pump inhibitors, healthcare providers need to be better educated about the potential side effects of these medications

Mixed norm estimates for the Ces\`aro means associated with Dunkl--Hermite expansions

Our main goal in this article is to study mixed norm estimates for the Ces\`{a}ro means associated with Dunkl--Hermite expansions on $\mathbb{R}^d$. These expansions arise when one consider the Dunkl--Hermite operator (or Dunkl harmonic oscillator) $H_{\kappa}:=-\Delta_{\kappa}+|x|^2$, where $\Delta_{\kappa}$ stands for the Dunkl--Laplacian. It is shown that the desired mixed norm estimates are equivalent to vector-valued inequalities for a sequence of Ces\`{a}ro means for Laguerre expansions with shifted parameter. In order to obtain the latter, we develop an argument to extend these operators for complex values of the parameters involved and apply a version of three lines lemma.Comment: 24 pages. Revised version following referee's comments. To appear in Transactions of the American Mathematical Societ

DEVELOPMENT OF A PERFORMANCE MONITORING SYSTEM TO OPTIMIZE PV BASED SOLAR ELECTRICITY GENERATION

Demand for electricity in Malaysia has seen a substantial hike in light of the nation’s rapid economic development in pursuit of achieving Vision 2020. The current method of generating electricity is through the use of conventional energy sources such as fossil fuels. However, consistent usage of fossil fuels has resulted in detrimental effects towards the environment besides the dampening amount of natural resources available globally. An alternative energy source that is capable of sustaining the demand is needed to ensure a sustainable future. Since its implementation through the Sustainable Energy Development Authority (SEDA), the Feed-in-Tariff (FiT) mechanism has established a total installed Photovoltaic (PV) capacity of 192 MW from 655 projects that are currently operational from the overall of 2628 approved projects in Malaysia

Survival Rates of Teeth with Primary Endodontic Treatment after Core/Post and Crown Placement

Introduction The objective of this study was to determine the effect of delayed placement of the core/post and crown on the outcomes of nonsurgical root canal therapy (NSRCT). Methods According to the Delta Dental of Wisconsin claims database, 160,040 NSRCTs were completed with a core/post and a crown placed before the end of the continuous coverage period or occurrence of an untoward event. Untoward events were defined as a retreatment, apicoectomy, or extraction as defined by the Code on Dental Procedures and Nomenclature. Statistical analysis was performed by using a multivariable Cox proportional hazards model. Results The survival rate from the time of crown placement to an untoward event was 99.1% at 1 year, 96.0% at 3 years, 92.3% at 5 years, and 83.8% at 10 years. Failure rates were greater when a core/post was placed more than 60 days after the NSRCT (adjusted hazard ratio, 1.08) and when the crown was placed more than 60 days after the core/post placement (adjusted hazard ratio, 1.14). Overall, the survival rates of NSRCT were greater when performed by an endodontist versus other providers. Conclusions On the basis of the information available from insurance claims data, this study shows that the long-term survival rates of initial endodontic therapy are adversely affected by the delayed placement of the final restoration and full coverage crown