Real Gap Research Articles

Balance Controller Design for Inverted Pendulum Considering Detail Reward Function and Two-Phase Learning Protocol

As a complex nonlinear system, the inverted pendulum (IP) system has the characteristics of asymmetry and instability. In this paper, the IP system is controlled by a learned deep neural network (DNN) that directly maps the system states to control commands in an end-to-end style. On the basis of deep reinforcement learning (DRL), the detail reward function (DRF) is designed to guide the DNN learning control strategy, which greatly enhances the pertinence and flexibility of the control. Moreover, a two-phase learning protocol (offline learning phase and online learning phase) is proposed to solve the “real gap” problem of the IP system. Firstly, the DNN learns the offline control strategy based on a simplified IP dynamic model and DRF. Then, a security controller is designed and used on the IP platform to optimize the DNN online. The experimental results demonstrate that the DNN has good robustness to model errors after secondary learning on the platform. When the length of the pendulum is reduced by 25% or increased by 25%, the steady-state error of the pendulum angle is less than 0.05 rad. The error is within the allowable range. The DNN is robust to changes in the length of the pendulum. The DRF and the two-phase learning protocol improve the adaptability of the controller to the complex and variable characteristics of the real platform and provide reference for other learning-based robot control problems.

Monetary and fiscal policy impacts under alternative trilemma regimes

Using a new set of trilemma indexes for exchange rate stability, financial market openness, and monetary policy independence, this paper first locates more than one hundred economies in the trilemma triangle over time. Second, the paper depicts individual economies’ trilemma regimes, defined by combinations of the three indexes, in the global map. Third, the paper tests econometrically the impact of monetary and fiscal policies on key macroeconomic variables (i.e., the real GDP growth rate gap, inflation, and their variability/volatility) under alternative trilemma regimes. Fourth, it examines the roles of trilemma regimes in influencing the macroeconomic variables. Econometric analysis uses a sample of 61 emerging market & developing economies over the period 1971–2020. The two-stage least squares estimation results largely support the Mundell-Fleming predictions made for three “corner” regimes. Monetary policy is effective in raising the real GDP growth rate gap and its variability under the “flexible exchange rate” corner regime, but not under the “financially open fixed rate” regime. Monetary policy is most effective in stimulating inflation and inflation volatility under the “flexible rate” regime. Fiscal policy has a positive impact on the GDP growth rate gap under the “flexible rate” regime and positive impacts on inflation and variability/volatility measures under the “financially closed fixed rate” regime, while it has no such impact under the “financially open fixed rate” regime, a somewhat surprising finding. The “financially open fixed rate” regime has a role of achieving price stability in a financially open economy.

CAN EXCHANGE RATE CONTROL IN TURKEY HELP THE CENTRAL BANK EVALUATIONS WITHIN THE FRAMEWORK OF THE TAYLOR RULE

This paper tests the validity of the Augmented Taylor rule in the Turkish economy for the period between February 2011 and February 2024 with the structural vector autoregression model. It is found that the central bank did not use the policy rate against deviations from inflation in the relevant period. On the other hand, the policy rate moves within expectations against deviations in the output gap and the real exchange rate. According to the structural impulse-response functions, the output gap and the inflation gap respond positively to a one-unit shock to the policy rate, while the real exchange rate reacts negatively. According to the results of structural variance decomposition, the most influential variable on changes in the policy rate is the real exchange rate deficit. In conclusion, the policy rate in the Turkish economy takes into account the output gap and the real exchange rate gap. However, it ignores the inflation gap.

Impact of Alpha Rays on the Optoelectronic Properties of Epoxy Resin Thick Films

Irradiated epoxy thick films are important for optical properties and may be used in many optical applications. This study aims to evaluate the effect of alpha irradiation on the optical and structural properties of epoxy thick films. Epoxy resin films were prepared by mixing epoxy resin (A) with hardener (B) at a mixing ratio of 3:1. Thus, specific thick films with thicknesses of 0.7 mm,0.8 mm and 1 mm were manufactured. Using visible and ultraviolet spectroscopy is one of the most important methods for studying polymers band gaps and electrical properties. The absorbance and transmittance spectra were used to investigate the optical properties of epoxy coatings of different thicknesses over a wavelength range of 300 nm–900 nm. Optical properties, such as absorption coefficient, refractive index, extinction coefficient, real dielectric constant, imaginary dielectric and optical band gap, were measured. The results show that the epoxy thick films have good optical transparency in the low-wavelength region. The results showed that increasing the thickness of the resin films decreased the optical energy gap and refractive index while increasing the absorption and extinction coefficients. In comparison, the effect of irradiation on an epoxy film of thickness 1 mm leads to an increase in the transmittance spectrum and energy gap and a decrease in the optical constants. The Fourier-transform infrared (FTIR) spectrum of the films was examined and showed the types of chemical bonds of the epoxy films before and after irradiation.

Non-utopian optical properties computed of a tomographically reconstructed real photonic band gap crystal

Non-utopian optical properties computed of a tomographically reconstructed real photonic band gap crystal

Competence or Experience

Competence or Experience

Experimental investigation of secondary flow losses in a variable geometry linear turbine cascade with winglet tip

Variable geometry turbines (VGT) hold a crucial role in gas turbines and variable cycle engines (VCE) by allowing adjustments to different operational conditions. In order to realize the adjustable function of the VGT stator blade, there will be partial gap structure at both ends of the stator blade, which will lead to partial leakage flow and serious secondary flow loss at the blade end that cannot be ignored, especially in a large angle adjustment range. At present, there are few researches on turbine cascades considering the real partial gap structure and winglet tip, and the numerical simulation calculation is mainly used, while the in-depth study using wind tunnel test is rarely seen. Therefore, this study attempts to analyze the internal flow characteristics of variable geometry turbine cascade by using five-hole pneumatic probe scanning and surface oil flow visualization, and discusses the mechanism of controlling partial clearance leakage flow and reducing secondary flow loss in the cascade by using winglet tip flow control technology. The winglet offset distance and the change of the relationship between the pivot and the clearance position on the flow field and flow loss is studied experimentally for the first time. The results show that the influence mechanism of winglet tip applied in VGT partial gap is quite different from that of typical blade tip clearance application, and more consideration should be given to the influence of pivot structure. Reasonable parameter selection can achieve a maximum loss reduction of 13.4 % and 20.2 % with and without pivot, respectively, while the unreasonable flow control scheme may lead to the loss or even increase with pivot. The interaction between the new secondary flow structure induced by pivot in the gap and other gap leakage flows is analyzed to explore the new mechanism of using winglet tip to reduce the loss of gap leakage flow.

Fighting Classroom Hunger : Analysis of Mid-day Meal Scheme of Odisha

India State Hunger Index (ISHI) reported that, “India is home to the world’s largest food insecure population, with more than 200 million people who are hungry.” Adding to this, the report urged that, the country’s poor performance is driven by its high levels of child under-nutrition and poor calorie count. Education plays a vital role in the development of human potential. State Governments are spending considerable portion of their resources to provide educational facilities all over the country. In spite of these efforts, the goal of cent percent universalization of elementary education appears to be far and elusive due to inherent socio-economic factors present in the society. Free and compulsory education up to the age of 14 years is the constitutional commitment and it is estimated that primary school children (6-14 years) form about 20% of the total population. Poor school enrolment and high school dropout rate are attributed to the poor nutritional status of the children compounded by poor socio-economic condition, child labour and lack of motivation. The researchers have used empirical research to find the real gap in the system.

Beijing as a Case Study of Educational Inequalities and Class-Induced Middle-Classization of School Districts

The negative impacts of class inequality on educational equity in terms of gender, regional development, economic capital, and cultural resources have gradually become a major social problem in China, but so far, relatively little academic attention has been paid to regional educational inequality. Therefore, this paper takes Beijing as a case city and adopts a questionnaire survey form that can reflect the real education gap in the class inequality situation to carry out a study on the generation mechanism and risk hazards of regional education inequality in Beijing. Comprehensive data from government reports, real estate markets, questionnaires, and other sources show that economic development, cultural background, and geographical location are the main causes of regional educational inequality in Beijing.

The effects of economic and financial shocks on private investment: A wavelet study of return and volatility spillovers

This paper examines the linkage between private investments and shocks in economic and financial indicators. Using data from India, we study the return and volatility spillovers from crude price, credit availability, real exchange rate, inflation, output gap, government spending, and economic policy uncertainty to private investments. We combine the ARMA-GARCH model with wavelet multiresolution analysis to capture the multiscale features of return and volatility spillovers among the time series. Our findings uncover spillovers in the time-scale decomposed series that are otherwise not observable in the original data, thereby throwing new light on the private investment-macroeconomic shock relationship. Private investment receives return spillovers from all variables at lower frequencies. Volatility spillovers from credit availability, exchange rate, output gap, and public investment exist at higher frequencies. The findings are robust to different forecast horizons, window sizes, frequency of data observation, and methodology of volatility extraction.

A Markov Model of Gap Occurrence in Continuous Glucose Monitoring Data for Realistic in Silico Clinical Trials

Background and objectiveContinuous glucose monitoring (CGM) sensors measure interstitial glucose concentration every 1-5 min for days or weeks. New CGM-based diabetes therapies are often tested in in silico clinical trials (ISCTs) using diabetes simulators. Accurate models of CGM sensor inaccuracies and failures could help improve the realism of ISCTs. However, the modeling of CGM failures has not yet been fully addressed in the literature. This work aims to develop a mathematical model of CGM gaps, i.e., occasional portions of missing data generated by temporary sensor errors (e.g., excessive noise or artifacts). MethodsTwo datasets containing CGM traces collected in 167 adults and 205 children, respectively, using the Dexcom G6 sensor (Dexcom Inc., San Diego, CA) were used. Four Markov models, of increasing complexity, were designed to describe three main characteristics: number of gaps for each sensor, gap distribution in the monitoring days, and gap duration. Each model was identified on a portion of each dataset (training set). The remaining portion of each dataset (real test set) was used to evaluate model performance through a Monte Carlo simulation approach. Each model was used to generate 100 simulated test sets with the same size as the real test set. The distributions of gap characteristics on the simulated test sets were compared with those observed on the real test set, using the two-sample Kolmogorov-Smirnov test and the Jensen-Shannon divergence. ResultsA six-state Markov model, having two states to describe normal sensor operation and four states to describe gap occurrence, achieved the best results. For this model, the Kolmogorov-Smirnov test found no significant differences between the distribution of simulated and real gap characteristics. Moreover, this model obtained significantly lower Jensen-Shannon divergence values than the other models. ConclusionsA Markov model describing CGM gaps was developed and validated on two real datasets. The model describes well the number of gaps for each sensor, the gap distribution over monitoring days, and the gap durations. Such a model can be integrated into existing diabetes simulators to realistically simulate CGM gaps in ISCTs and thus enable the development of more effective and robust diabetes management strategies.

THE EFFECTS OF COVID-19 ON RESIDENTIAL PROPERTY PRICES IN MALAYSIA

The physical distancing, lockdown, and other measures due to the COVID-19 pandemic have caused massive job loss and economic hardship, which would result in people not being able to pay their mortgages or rent. Thus, the main objective of this study is to examine the effects of the Gross Domestic Product (GDP), inflation, investment, and interest rate on residential property prices in Malaysia before and during COVID-19. This research utilises the annual time series data from 1990 to 2020, and the empirical analysis is conducted using the multiple linear regression analysis modelling approach. The finding shows that GDP and interest rates are positive and statistically significant with residential property prices. Practitioners can use these findings to understand the pandemic's effect on house prices. This will provide some guidelines for a policy formulation to moderate the increase in residential property prices to maintain the country's economic stability and indirectly help the government realise its vision of becoming a high-income country between 2024 and 2028. This is the first study that examines the pricing behaviour of Malaysian house prices concerning the COVID-19 shocks. In addition, the study contributes to regional housing price studies by bridging the real estate literature gap.

Design and performance evaluation of a slit-slat camera for 2D prompt gamma imaging in proton therapy monitoring: A Monte Carlo simulation study.

We investigated the design of a prompt gamma camera for real-time dose delivery verification and the partial mitigation of range uncertainties. A slit slat (SS) camera was optimized using the trade-off between the signal-to-noise ratio and spatial resolution. Then, using the GATE Monte Carlo package, the camera performances were estimated by means of target shifts, beam position quantification, changing the camera distance from the beam, and air cavity inserting. A homogeneous PMMA phantom and the air gaps induced PMMA phantom were used. The air gaps ranged from 5mm to 30mm by 5mm increments were positioned in the middle of the beam range. To reduce the simulation time, phase space scoring was used. The batch method with five realizations was used for stochastic error calculations. The system's detection efficiency was PGs/proton) for a 10 × 20 cm2 detector (source-to-collimator distance=15.0cm). Axial and transaxial resolutions were 23mm and 18mm, respectively. The SS camera estimated the range as 69.0±3.4 (relative stochastic error 1-sigma is 5%) and 67.6±1.8mm (2.6%) for the real range of 67.0mm for 107 and 108 protons of 100 MeV, respectively. Considering 160 MeV, these values are 155.5±3.1 (2%) and 152.2±2.0mm (1.3%) for the real range of 152.0mm for 107 and 108 protons, respectively. Considering phantom shift, for a 100 MeV beam, the precision of the quantification (1-sigma) in the axial and lateral phantom shift estimation is 2.6mm and 1mm, respectively. Accordingly, the axial and lateral quantification precisions were 1.3mm and 1mm for a 160 MeV beam, respectively. Furthermore, the quantification of an air gap formulated as , where and gapreal are the estimated and real air gap, respectively. The precision of the air gap quantification is 1.6mm (1 sigma). Moreover, 2D PG images show the trajectory of the proton beam through the phantom. The proposed slit-slat imaging systems can potentially provide a real-time, in-vivo, and non-invasive treatment monitoring method for proton therapy.

Earnings losses of displaced workers in times of crisis

AbstractWe utilize data from the 1979 National Longitudinal Survey of Youth and the Bureau of Labor Statistics to study how the earnings losses experienced by displaced workers vary in times of economic crisis. Relative to an economy that operates at full potential, our results show that a 1% increase in the real gross domestic product gap observed at the time of displacement is associated with an additional increase in the estimated earnings losses experienced by displaced workers of approximately 4.3% in the year immediately following displacement, and with similar increases in the estimated losses for up to 5 years after.

Dynamic Deformation Behaviors of the Levitation Electromagnets of High-Speed Maglev Vehicle Negotiating a Sharp Horizontal Curve

The elastic deformation of the levitation electromagnet (LM) of the high-speed maglev vehicle brings uneven levitation gaps and displacement differences between measured gap signals and the real gap in the middle of the LM, and then reduces dynamic performances of the electromagnetic levitation unit. However, most of the published literature has paid little attention to the dynamic deformation of the LM under complex line conditions. In this paper, considering the flexibility of the LM and the levitation bogie, a rigid-flexible coupled dynamic model is established to simulate deformation behaviors of the LMs of the maglev vehicle passing through the 650 m radius horizontal curve. Simulated results indicate that the deflection deformation direction of the same LM on the front transition curve is always opposite to that on the rear transition curve. Similarly, the deflection deformation direction of a left LM on the transition curve is opposite to that of the corresponding right LM. Furthermore, deflection deformation amplitudes of the LMs in the middle of the vehicle are always very small (less than 0.2 mm). However, the deflection deformation of the LMs at both ends of the vehicle is considerably large, and the maximum deflection deformation is about 0.86 mm when the vehicle passes at the balance speed. This forms a considerable displacement disturbance for the nominal levitation gap of 10 mm. It is necessary to optimize the supporting structure of the LM at the end of the maglev train in the future.

The role amenities play in spatial sorting of migrants and their impact on welfare: Evidence from China.

From 2005 to 2015, China's high-skilled labor was increasingly concentrated in cities with high wages and high rents, while a narrowing of the wage gap between high- and low-skilled labor showed an opposite trend to an increase in geographic sorting. In this research, I estimated a spatial equilibrium structural model to identify the causes of this phenomenon and its impact on welfare. Changes in local labor demand essentially led to an increase in skill sorting, and changes in urban amenities further contributed to this trend. An agglomeration of high-skilled labor raised local productivity, increased wages for all workers, reduced the real wage gap, and widened the welfare gap between workers with different skills. In contrast to the welfare effects of changes in the wage gap driven by exogenous productivity changes, changes in urban wages, rents, and amenities increased welfare inequality between high- and low-skilled workers, but this is mainly because the utility of low-skilled workers from urban amenities is constrained by migration costs; if migration costs caused by China's household registration policy were eliminated, changes in urban wages, rents, and amenities would reduce welfare inequality between high- and low-skilled workers to a greater extent than a reduction in the real wage gap between these two groups.

Learning Streamed Attention Network from Descriptor Images for Cross-Resolution 3D Face Recognition

In this article, we propose a hybrid framework for cross-resolution 3D face recognition which utilizes a Streamed Attention Network (SAN) that combines handcrafted features with Convolutional Neural Networks (CNNs). It consists of two main stages: first, we process the depth images to extract low-level surface descriptors and derive the corresponding Descriptor Images (DIs), represented as four-channel images. To build the DIs, we propose a variation of the 3D Local Binary Pattern (3DLBP) operator that encodes depth differences using a sigmoid function. Then, we design a CNN that learns from these DIs. The peculiarity of our solution consists in processing each channel of the input image separately, and fusing the contribution of each channel by means of both self- and cross-attention mechanisms. This strategy showed two main advantages over the direct application of Deep-CNN to depth images of the face; on the one hand, the DIs can reduce the diversity between high- and low-resolution data by encoding surface properties that are robust to resolution differences. On the other, it allows a better exploitation of the richer information provided by low-level features, resulting in improved recognition. We evaluated the proposed architecture in a challenging cross-dataset, cross-resolution scenario. To this aim, we first train the network on scanner-resolution 3D data. Next, we utilize the pre-trained network as feature extractor on low-resolution data, where the output of the last fully connected layer is used as face descriptor. Other than standard benchmarks, we also perform experiments on a newly collected dataset of paired high- and low-resolution 3D faces. We use the high-resolution data as gallery, while low-resolution faces are used as probe, allowing us to assess the real gap existing between these two types of data. Extensive experiments on low-resolution 3D face benchmarks show promising results with respect to state-of-the-art methods.

Accreditation of primary health care centres in the KSA: Lessons from developed and developing countries

Background/ObjectivesIn 2013, the KSA made Central Board for Accreditation of Healthcare Institutions (CBAHI) accreditation mandatory for all healthcare facilities, including primary health care centres (PHCs) and set a target to have 502 PHCs accredited by 2020. However, there is a real gap in knowledge and research on the impact of CBAHI accreditation on PHCs. This absence of research has been linked to the lack of understanding of the accreditation programme. Therefore, it was recommended by scholars that the KSA could learn from the experience of other countries to improve policy implementation and avoid future complications. MethodsThis study aimed to explore lessons that KSA can draw from developed and developing countries that have implemented accreditation programmes for PHCs. We performed a literature review using a systematic approach to identify articles related to the accreditation of PHCs. The identified articles were examined by applying evaluation criteria in respect of prospective policy transfer. ResultsThe research results yielded 22 publications from different countries. There were variations among the countries in the specific information acquired. However, Denmark had the highest number of articles providing detailed information. Regarding their aims, most studies shared the same goal of improving quality and patient safety. Generally, there was limited discussion of policy failure compared with policy success. In addition, most of the countries were in the process of implementing local accreditation. Almost all of the countries that had implemented external programmes were developing countries. In terms of application criteria, most cases made recommendations for the programme or for PHCs. ConclusionAnalysis indicated that because of the differences in information between countries and settings, there is no ideal country-based experience from which the KSA can transfer lessons. Lessons from outside the KSA would need careful consideration when adopting them in the local context of the Kingdom.

The Nexus between Unemployment and Economic Growth in Egypt: Revisiting Okun's Law

This paper investigates the validity of Okun’s Law to the Egyptian economy through the period 1991 until 2021 using Autoregressive Distributed Lag (ARDL) model technique. The paper applies Augmented Dickey-Fuller (ADF) and Phillips – Perron (PP) to perform the unit root test. It is found that the three variables in the model, natural logarithm of real GDP difference LNRGDPdif, natural logarithm of real GDP gap LNRGDPgap, and natural logarithm of unemployment rate difference LNUNdif, are integrated of order zero I(0). While the other variable, natural logarithm of unemployment rate gap LNUNgap, is integrated of order one I(1). Therefore, the paper finds justification to conduct the ARDL bounds test for co-integration for the two Okun’s Law versions. However, the paper finds that the results are incompatible with economic theory and contradict most of research papers conducted for other countries. The coefficient of LNUNdif is (= 0.0004) and found to be insignificant while the coefficient of (LNRGDPdif (-1)) is the only significant coefficient at 5% significance level (= -2). Of course, these results in addition to the ARDL Bounds Tests’ results give evidence that there is no relationship between real GDP and unemployment rate in Egypt neither in the long run nor in the short run. Therefore, Okun’s Law, with difference model and gap model, is not valid in case of Egypt. These findings can be attributed to the low level of data accuracy and reliability. As a result, it is recommended for the Egyptian government to direct more effort towards collecting and publishing more accurate and reliable data on socio-economic variables.

Experimental Verification of 2.4 kVAr and 12 kVAr Prototype Variable Inductors Controlled By Virtual Air Gaps With Magnetic Orthogonality

This paper describes experimental verification of single-phase variable inductor prototypes rated at 2.4 kVAr (75 mH, 10 A, 230 V, 24 kg) and 12 kVAr (43 mH, 30 A, 400 V, 78 kg). Results for much smaller devices rated at 1-10 Var are also shown. The variability of inductance of the main AC winding was achieved by adding a DC winding, wound through the apertures placed symmetrically in the core such that both windings were magnetically orthogonal. Local saturation caused by the magnetic field due to DC winding creates virtual air gaps. This method is capable of lowering the main inductance by over 90% if no real air gap is present, but for industrial applications the range of variability is likely to be closer to 20-30% range, depending on the size of the real air gap in the magnetic circuit. The amount of variation/control can be improved by using more than one control winding. Very good repeatability of performance was observed, with relatively small total harmonic distortion introduced due to control. The experimental findings agree with a generalised analytical model.