Extensions of the External Validation for Checking Learned Model Interpretability and Generalizability.

We discuss the validation of machine learning models, which is standard practice in determining model efficacy and generalizability. We argue that internal validation approaches, such as cross-validation and bootstrap, cannot guarantee the quality of a machine learning model due to potentially biased training data and the complexity of the validation procedure itself. For better evaluating the generalization ability of a learned model, we suggest leveraging on external data sources from elsewhere as validation datasets, namely external validation. Due to the lack of research attractions on external validation, especially a well-structured and comprehensive study, we discuss the necessity for external validation and propose two extensions of the external validation approach that may help reveal the true domain-relevant model from a candidate set. Moreover, we also suggest a procedure to check whether a set of validation datasets is valid and introduce statistical reference points for detecting external data problems

Performance comparison of PEMFC hydrogen reformer with different controllers

The renewable energy technology has become very popular due to major constraint in the existing electrical system such as high electricity demand, increased in fuel prices and concern of environmental pollution. The aims of this project are to develop a complete Proton Exchange Membrane Fuel Cell (PEMFC) model with hydrogen reformer by using MATLAB/ Simulink with three different controllers and comparison between the three controllers will be discussed. This project presents the development of methods to solve the problem of PEMFC output voltage by using different controllers which are Proportional Integral (PI), Proportional Integral Derivatives (PID) and Proportional Integral Fuzzy (PI-Fuzzy) controllers. The Ziegler Nicholas tuning method is used to tune PI and PID gains in a Simulink model. It helps the system to achieve a balance between performance and robustness for both controllers. The Mamdani type was used to develop the fuzzy controller in Simulink model. The transient performances that will be discussed are rise time, settling time, maximum overshoot, and percentage of overshoot. The results show that the proposed PI-Fuzzy is better than the conventionally used PI and PID controllers

A Comparative Study on Process Potentials for Frictional Stir- and Electric Hot-assisted Incremental Sheet Forming

Abstract Incremental sheet forming (ISF), as an advanced forming technique, has received increasing interest from both academia and industry due to its improved formability, greater process flexibility and reduced energy consumption in its life cycle. However, with the growing application of lightweight alloys with very limited material elongation, conventional ISF inevitably encounters challenges in processing these alloys at room temperature, especially in forming magnesium and titanium alloys. Therefore, heat-assisted ISF techniques have been proposed to further enhance material formability at elevated temperatures. In this work, two heat-assisted ISF approaches, frictional stir- and electric hot- assisted ISF, have been employed to process the hard-to-form materials in terms of the flexibility and local dynamic heating. The temperature evolution and corresponding forming force at different feed rates of these two techniques, is investigated in detail to build up a processing window. In addition, process capabilities are compared by forming different geometrical shapes of magnesium alloy AZ31B of 1.4 mm sheet thickness. The investigation results show the pros and cons of frictional stir- and electric hot- assisted ISF. Frictional stir-assisted ISF is more efficient than electric hot-assisted ISF under current experimental results. However, electric hot-assisted ISF has faster heating rate which makes this technique less dependent on the component geometry

Voltage Tracking of a Multi-Input Interleaved Buck-Boost DC-DC Converter Using Artificial Neural Network Control

This paper proposes an artificial neural network (ANN) voltage tracking of multi-input interleaved buck-boost DC-DC converter. A back-propagation algorithm topology is implemented in this paper. The control unit is implemented to ameliorate the performance of the proposed multi-input converter during transient dynamic response and steady-state operation mode. The neural network controller unit design, which is adaptive against output voltage command tracking and reference voltage variations is proposed. The proposed design has been verified through the MATLAB software. The simulation outcomes emphasized the validity and reliability of the proposed neural network technique, which would be a promising an efficient control method that ensures multi-input converter suitable for electric vehicle and renewable energy application system

Lattice worldline representation of correlators in a background field

We use a discrete worldline representation in order to study the continuum limit of the one-loop expectation value of dimension two and four local operators in a background field. We illustrate this technique in the case of a scalar field coupled to a non-Abelian background gauge field. The first two coefficients of the expansion in powers of the lattice spacing can be expressed as sums over random walks on a d-dimensional cubic lattice. Using combinatorial identities for the distribution of the areas of closed random walks on a lattice, these coefficients can be turned into simple integrals. Our results are valid for an anisotropic lattice, with arbitrary lattice spacings in each direction.Comment: 54 pages, 14 figure

HIV-1 integrase polymorphisms are associated with prior antiretroviral drug exposure

In a recent summary of integrase sequences, primary integrase inhibitor mutations were rare. In a review of integrase inhibitor-naïve Australian HIV-1 sequences, primary mutations were not identified, although the accessory mutation G140S was detected. A link with previous antiretroviral therapy, intra-subtype B divergence across the integrase gene and transmission of integrase polymorphisms were also noted. Based on these findings, we would recommend ongoing surveillance of integrase mutations, and integrase region sequencing for patients prior to commencement of integrase inhibitors

Impacts of monetary policies on the real estate bubble in Hanoi, Vietnam

The development of the real estate market always goes hand in hand with the fluctuation of the economy. In recent years, this market has experienced many recessions and «freezes» associated with the appearance of a real estate bubble. To approach this issue, this paper studies and gives an overview of the real estate bubble and the impact of monetary policies on the real estate bubble in Vietnam. This paper’s purpose is to identify and measure the influence of monetary policies, including interest rates, credit and money supply, on the real estate bubble in Ha Noi. The vector autoregression model (VAR) is used to test the interaction of the variables in the model. Dickey-Fuller test (DF) is applied to determine the stationarity of the variables, while the Akaike information criterion (AIC), Likelihood Ratio (LR), Final prediction error (FPE), Hannan-Quinn information criterion (HQ) and Schwarz criterion (SC) are used to find optimal lag of the model; then Granger causality test is utilized to determine the two-way correlation between variables. The results showed that the real estate bubble reacted quickly to shocks from macroeconomic factors representing the monetary policy, consisting of interbank interest rates, credit growth, and money supply growth. Thus, it is concluded that monetary policy is not only the cause of formation, but also one of the effective solutions to deflate the real estate bubble. AcknowledgmentThis research is funded by Vietnam Ministry of Education and Training (MOET) under grant number [B2022-NTH-03]

A reporting tool for practice guidelines in healthcare: the RIGHT Statement

The quality of reporting of practice guidelines is often poor and there is no widely accepted guidance or standards for the reporting of practice guidelines in healthcare. An international working group (the RIGHT working group) was therefore established to address this gap. The group followed an existing framework for developing health research reporting guidelines and the EQUATOR (Enhancing the QUAlity and Transparency Of health Research) Network approach. We developed a checklist and an explanation and elaboration document. The RIGHT checklist includes 22 items that we consider essential for good reporting of practice guidelines. These items encompass basic information (items 1-4), background (items 5-9), evidence (items 10-12), recommendations (items 13-15), review and quality assurance (items 16-17), funding and declaration and management of interests (items 18-19), and other information (items 20-22). The RIGHT checklist can assist developers when reporting their guidelines, support journal editors and peer reviewers when considering guideline reports, and help healthcare practitioners understand and implement a guideline

Effective Interventions and Decline of Antituberculosis Drug Resistance in Eastern Taiwan, 2004–2008

BACKGROUND: The Taiwan health authority recently launched several tuberculosis (TB) control interventions, which may have an impact on the epidemic of drug-resistant TB. We conducted a population-based antituberculosis drug resistance surveillance program in Eastern Taiwan to measure the proportions of notified TB patients with anti-TB drug resistance and the trend from 2004 to 2008. METHODS AND FINDINGS: All culture-positive TB patients were enrolled. Drug susceptibility testing results of the first isolate of each TB patient in each treatment course were analyzed. In total, 2688 patients were included, of which 2176 (81.0%) were new TB cases and 512 (19.0%) were previously treated cases. Among the 2176 new TB cases, 97 (4.5%) were retreated after the first episode of TB treatment within the study period. The proportion of new patients with any resistance, isoniazid resistance but not multidrug-resistant TB (resistant to at least isoniazid and rifampin, MDR-TB), and MDR-TB was 16.4%, 7.5%, and 4.0%, respectively, and that among previously treated cases was 30.9%, 7.9%, and 17.6%, respectively. The combined proportion of any resistance decreased from 23.3% in 2004 to 14.3% in 2008, and that of MDR-TB from 11.5% to 2.4%. CONCLUSIONS: The proportion of TB patients with drug-resistant TB in Eastern Taiwan remains substantial. However, an effective TB control program has successfully driven the proportion of drug resistance among TB patients downward