Adjustable Window Research Articles

Raining-inspired method for construction of porous film material

The low-temperature environment caused by solvent evaporation leads to the condensation of water vapor into water droplets that remain on the surface of the film to form breath figure patterns. The conventional approach to regulate the pore morphology in the breath figure process is to optimize the ambient temperature, humidity, and solution concentration. However, realizing a wide adjustable window of pore size and uniform distribution of the pore are still challenges. Here, inspired by the rainfall phenomenon, we proposed a simple and efficient method called the “raining boxing method” (RBM) for preparing porous films based on exogenously given water droplets as templates. The RBM broadened the adjustable window of pore size (0.6–225 µm in this work) and solved the inherent problem of radial reduction of pore size from the film center to the edge caused by the significant difference in low-temperature duration at different locations accompanying the solvent evaporation process. Furthermore, this method could realize multi-types porous films, including surface porous films, spongy porous films, and honeycomb porous films, and could be universally applied in the casting process of various polymer solutions.

Human Velocity Estimation Using Kalman Filter and Least Squares With Adjustable Window Sizes for Mobile Robots

Human Velocity Estimation Using Kalman Filter and Least Squares With Adjustable Window Sizes for Mobile Robots

Negative Design Margin Realization through Deep Path Activity Detection Combined with Dynamic Voltage Scaling in a 55 nm Near-Threshold 32-Bit Microcontroller.

This paper presents an innovative approach for predicting timing errors tailored to near-/sub-threshold operations, addressing the energy-efficient requirements of digital circuits in applications, such as IoT devices and wearables. The method involves assessing deep path activity within an adjustable window prior to the root clock's rising edge. By dynamically adapting the prediction window and supply voltage based on error detection outcomes, the approach effectively mitigates false predictions-an essential concern in low-voltage prediction techniques. The efficacy of this strategy is demonstrated through its implementation in a near-/sub-threshold 32-bit microprocessor system. The approach incurs only a modest 6.84% area overhead attributed to well-engineered lightweight design methodologies. Furthermore, with the integration of clock gating, the system functions seamlessly across a voltage range of 0.4 V-1.2 V (5-100 MHz), effectively catering to adaptive energy efficiency. Empirical results highlight the potential of the proposed strategy, achieving a significant 46.95% energy reduction at the Minimum Energy Point (MEP, 15 MHz) compared to signoff margins. Additionally, a 19.75% energy decrease is observed compared to the zero-margin operation, demonstrating successful realization of negative margins.

A robotic arm control system with simultaneous and sequential modes combining eye-tracking with steady-state visual evoked potential in virtual reality environment.

At present, single-modal brain-computer interface (BCI) still has limitations in practical application, such as low flexibility, poor autonomy, and easy fatigue for subjects. This study developed an asynchronous robotic arm control system based on steady-state visual evoked potentials (SSVEP) and eye-tracking in virtual reality (VR) environment, including simultaneous and sequential modes. For simultaneous mode, target classification was realized by decision-level fusion of electroencephalography (EEG) and eye-gaze. The stimulus duration for each subject was non-fixed, which was determined by an adjustable window method. Subjects could autonomously control the start and stop of the system using triple blink and eye closure, respectively. For sequential mode, no calibration was conducted before operation. First, subjects' gaze area was obtained through eye-gaze, and then only few stimulus blocks began to flicker. Next, target classification was determined using EEG. Additionally, subjects could reject false triggering commands using eye closure. In this study, the system effectiveness was verified through offline experiment and online robotic-arm grasping experiment. Twenty subjects participated in offline experiment. For simultaneous mode, average ACC and ITR at the stimulus duration of 0.9 s were 90.50% and 60.02 bits/min, respectively. For sequential mode, average ACC and ITR at the stimulus duration of 1.4 s were 90.47% and 45.38 bits/min, respectively. Fifteen subjects successfully completed the online tasks of grabbing balls in both modes, and most subjects preferred the sequential mode. The proposed hybrid brain-computer interface (h-BCI) system could increase autonomy, reduce visual fatigue, meet individual needs, and improve the efficiency of the system.

The Impact of Covid-19 Pandemic on Islamic Health Insurance Market Returns: Empirical Evidence from Saudi Arabia

This study aims to identify the impact of COVID-19 on the Cooperative Health Insurance (CHI) Market in Saudi Arabia by applying Event Study Methodology. The health event identified in this study is the announcement of the first positive case of COVID-19 in Saudi Arabia, which the Ministry of Health announced on March 2, 2020. For this study, the daily price of 24 cooperative health insurance companies listed on the Saudi Stock Market (Tadawul) and the market index (TASI) for the same period (June 05, 2018 - March 30, 2020) were collected. The abnormal returns are calculated using the Capital Asset Pricing Model (CAPM). The study found a negative effect of the COVID-19 pandemic on the health insurance companies in Saudi Arabia during the first week of the anticipation period that continued until the event day. Negative abnormal returns persisted until the end of the total study period but were not statistically significant except on only three days during the post-event window (March 05, 08, and 09, 2020). This means the Saudi cooperative insurance market experienced a period of anticipation and anxiety before the announcement of the first case of Covid-19; however, the information was insufficient and unconfirmed. During the adjustment window, the market tried to adjust itself and react to the event efficiently, but it could not do so. The results of this study are useful to takaful investors, operators, and regulators in the Islamic insurance markets and to researchers and academicians.

Topic: A Study of Informational Efficiency in Nifty 50 - Event Study.

Market efficiency and asset pricing  has been intriguing topic for all financial economists.  Researchers have been actively studying on the various aspects of market microstructure and market efficiency since 1950s. The area still holds its significance ,as newer dimensions are being explored. The objective of this paper is to study Informational efficiency of Nifty -50 and how events like result announcements impacts the efficiency of individual stock. Efficient market hypothesis implies that the stocks follow random walk and it is impossible to make trading strategies in the longer run. In shorter period there may be a lag between the stock prices and new information related to the stocks, however it adjusts very quickly. In this paper we have tested for the random walk of Nifty in two different time horizon and Informational efficiency of three heavy weighted stocks of Nifty 50. Another pilot study has been calculated on top three heavy weighted stocks of Nifty -50 to check informational efficiency and how quickly stocks adjust to new information in the form of results. The methodologies used to test the hypothesis are ‘Variance ratio’ introduced by (Lo and Mackinlay,1998)  and then used by many researchers for the test of random walk. (Omar, S. et al 2018; Cao, C. et al 2017; Charles and Darne, 2009,) and Event Study methodology. Findings of the study shows that the Nifty -50 does not follow random walk phenomenon, neither in the short long and nor in the long run. The pilot study of Informational efficiency found that two heavy weighted stocks (Reliance Industries and HDFC bank) shows that event has a significant impact on the stocks, Moreover the market was not able to factor the available information the stocks declined in the adjustment window as well. The null hypothesis of CAR being equal to 0 has been rejected and Null hypothesis is accepted. In both the test the Semi -Weak form of market efficiency has been rejected.

Window Function Design for Asymmetric Beampattern Synthesis and Applications

This letter proposes a novel window function design to synthesize asymmetric beampatterns while minimizing the gain loss for clutter/interference suppression as required in practical applications, such as airborne phased array radar (APAR). Compared with beampattern synthesis in terms of designing the weight vector directly, the proposed method can achieve asymmetric sidelobes for multiple steering directions resort to designing one window while circumventing repetitive computations. To tackle the resultant non-convex optimization problem, an iterative alternating optimization (IAO) algorithm is introduced where each iteration involves multiple subproblems that can be solved via either convex approximation (CA) approach or closed-form solutions. Finally, numerical simulations are provided to verify the effectiveness of the proposed method comparing with the classical adjustable window functions (CAWFs).

FIR Filter Design using Raised Semi-ellipse Window Function

In this paper, a new two-parameter window function - Raised semi-ellipse (RSE) is proposed. The window is obtained from a fixed elliptical window known as Semi-ellipse window by raising the radius of the minor axis by the parameter (β), and applied for the design of finite impulse response (FIR) digital filters. The spectral parameters of the proposed window are determined first and compared with the Kaiser window – a 2-parameter adjustable window. Subsequently, in its application in filter design with an established design algorithm, the newly proposed adjustable window is compared to the Semi-ellipse window to examine its improvement and also the Kaiser window to compare its performance with a commonly used adjustable window. The filter simulation results show that the filters designed with the proposed window can provide more reduced ripples than the Kaiser window for prescribed spectral characteristics.

The data-processing multiverse of event-related potentials (ERPs): A roadmap for the optimization and standardization of ERP processing and reduction pipelines

In studies of event-related brain potentials (ERPs), numerous decisions about data processing are required to extract ERP scores from continuous data. Unfortunately, the systematic impact of these choices on the data quality and psychometric reliability of ERP scores or even ERP scores themselves is virtually unknown, which is a barrier to the standardization of ERPs. The aim of the present study was to optimize processing pipelines for the error-related negativity (ERN) and error positivity (Pe) by considering a multiverse of data processing choices. A multiverse analysis of a data processing pipeline examines the impact of a large set of different reasonable choices to determine the robustness of effects, such as the impact of different decisions on between-trial standard deviations (i.e., data quality) and between-condition differences (i.e., experimental effects). ERN and Pe data from 298 healthy young adults were used to determine the impact of different methodological choices on data quality and experimental effects (correct vs. error trials) at several key stages: highpass filtering, lowpass filtering, ocular artifact correction, reference, baseline adjustment, scoring sensors, and measurement procedure. This multiverse analysis yielded 3,456 ERN scores and 576 Pe scores per person. An optimized pipeline for ERN included a 15 Hz lowpass filter, ICA-based ocular artifact correction, and a region of interest (ROI) approach to scoring. For Pe, the optimized pipeline included a 0.10 Hz highpass filter, 30 Hz lowpass filter, regression-based ocular artifact correction, a -200 to 0 ms baseline adjustment window, and an ROI approach to scoring. The multiverse approach can be used to optimize pipelines for eventual standardization, which would support efforts toward establishing normative ERP databases. The proposed process of analyzing the data-processing multiverse of ERP scores paves the way for better refinement, identification, and selection of data processing parameters, ultimately improving the precision and utility of ERPs.

Design of FIR digital filters using Semi-ellipse window

A fixed window function which is similar in shape to a semi-ellipse is proposed. The semi–ellipse which has its major axis to be equal to the window length and the minor axis at unity produced about 4.2 dB lower ripple ratio than the rectangular window. The proposed window function is derived from the equation of an ellipse in the explicit and parametric forms. First of all, the spectral characteristic of the proposed window is studied in terms of spectral parameters and compared with other fixed windows like Rectangular, Bartlett, Hann, Hamming and Blackman windows. The window simulation results reveal that the proposed window produced comparable spectral characteristic with existing standard fixed windows. Secondly, the paper presents the application of the proposed window in a digital filter design. The filter analysis comparison results with other fixed windows namely Bartlett, Von Hann, Hamming, and Kaiser window, an adjustable window, confirm that filter design with the proposed window exhibits good spectral characteristic, and can be used to design better filter than the Bartlett window using less than half the Bartlett’s filter length for a fixed transition width. The similicity of its coefficients formulation and design algorithm makes it a good choice for digital filter design applications.

Evaluating the Applicability of a Quantile–Quantile Adjustment Approach for Downscaling Monthly GCM Projections to Site Scale over the Qinghai-Tibet Plateau

In the context of global climate change, the Qinghai-Tibetan plateau (QTP) has experienced unprecedented changes in its local climate. While general circulation models (GCM) are able to forecast global-scale future climate change trends, further work needs to be done to develop techniques to apply GCM-predicted trends at site scale to facilitate local ecohydrological response studies. Given the QTP’s unique altitude-controlled climate pattern, the applicability of the quantile–quantile (Q-Q) adjustment approach for this purpose remains largely unknown and warrants investigation. In this study, this approach was evaluated at 36 sites to ensure the results are representative of different climatic and surface conditions on the QTP. Considering the practical needs of QTP studies, the study aims to assess its capability for downscaling monthly GCM simulations of major variables onto the site scale, including precipitation, air temperature, wind speed, relative humidity, and air pressure, based on two GCMs. The calibrated projections at the sites were verified against the observations and compared with those from two commonly used adjustment methods—the quantile-mapping method and the delta method. The results show that the general trends of most variables considered are well adjusted at all sites, with a quantile pair of 25–75% for all the variables except precipitation where 10–90% is used. The calibrated results are generally close to the observed values, with the best performance in air pressure, followed by air temperature and relative humidity. The performance is relatively limited in adjusting wind speed and precipitation. The accuracies decline as the adjustment extends into the future; a wider adjustment window may help increase the performance for the variables subject to climate changes. It is found that the performance of the adjustment is generally independent of the locations and seasons, but is strongly determined by the quality of GCM simulations. The Q-Q adjustment works better for the meteorological variables with fewer fluctuations and daily extremes. Variables with more similarities in probability density functions between the observations and GCM simulations tend to perform better in adjustment. Generally, this approach outperforms the two peer methods with broader applicability and higher accuracies for most major variables.

Adjustable window for 2D PIV estimation based on local Lagrangian coherency

We present a novel approach to adjust shapes of the interrogation windows (IW) in Particle Image Velocimetry (PIV) measurements as a function of temporal and spatial local coherent motions. Lagrangian Coherent Structures (LCS) has been widely utilized to determine local flow boundaries. We propose using Finite-Time Lyapunov Exponent (FTLE) to quantify LCS separatrix boundaries (i.e. ridges) and adjust the interrogation window. We integrated the proposed method with a local optical flow PIV algorithm. The evaluation was performed using synthetic particle images of 2D homogeneous isotropic turbulence obtained from Direct Numerical Simulation (DNS). The results showed significant improvements in regions with complex flow behaviours, particularly shear, vortex and hyperbolic motions. We studied improvements of the velocity estimation in a real experiment of the wake flow behind a cylinder at Reynolds number equal to 3900. It was found that optical flow featured by coherency based interrogation window (coherent optical flow) reveals detailed vector field estimations in regions with complex behaviours inside the wake flow.

Возможности применения жидкостно-кольцевого вакуумного насоса с автоматическим регулируемым нагнетательным окном при измельчении виноградных семян и выжимок

Для повышения сохранения биологически активных веществ, уменьшения энергопотребления в процессе измельчения и получения порошка заданной степени помола из виноградных выжимок и семян предлагается использование установки двухступенчатой дисково-шаровой вакуумной мельницы. Предложенная конструкция двухступенчатой мельницы оказывает влияние на безопасность работы (исключаются взрывы) и экологичность (не создает запыленности окружающей среды). В конструкции разработанной установки важным объектом является вакуумный насос. Приведены устройство и основные принципы работы классического одноступенчатого водокольцевого вакуумного насоса производства ОАО «БЕСКОМ» и жидкостно-кольцевого вакуумного насоса с возможностью автоматического регулирования размеров нагнетательного окна, разработанного в ФГБОУ ВО «ТГТУ» на кафедре «МИГ». Показаны основные преимущества предлагаемого насоса по сравнению с классическим вариантом. На основе испытаний был проведен сравнительный анализ разработанного жидкостно-кольцевого вакуумного насоса с автоматическим регулируемым размером нагнетательного окна и классического вакуумного насоса равной быстроты действия, результаты которого продемонстрировали существенную эффективность использования первой машины. Установлено, что затраты удельной мощности в процессе транспортирования растительных порошков на 20-25% ниже при равной быстроте действия. Экономический расчет демонстрирует эффективность применения новой конструкции разработанного вакуумного насоса в технологическом процессе тонкого измельчения сухих растительных продуктов за счет вакуумного отвода заданной фракции помола. Поэтому разработанный насос рекомендуется использовать для измельчения сухих сыпучих растительных продуктов на крупных перерабатывающих предприятиях агропромышленного комплекса, пищевой, фармацевтической и парфюмерной отраслях промышленности. To increase the preservation of biologically active substances, reduce energy consumption in the grinding process and obtain a powder of a given degree of grinding from grape pomace and seeds, it is proposed to use a two-stage disk-ball vacuum mill. The proposed design of a two-stage mill affects the safety of work (excluding explosions) and environmental friendliness (does not create a dusty environment). An important object in the design of the developed installation is the vacuum pump. The device and basic principles of operation of a classic single-stage liquid ring vacuum pump manufactured by JSC "BESCOM" and a liquid ring vacuum pump with the ability to automatically adjust the size of the discharge window, developed at the TSTU Department of MIG are presented. The main advantages of the proposed pump in comparison with the classic version are shown.Based on the tests, a comparative analysis of the developed liquid ring vacuum pump with an automatically adjustable discharge window size and a classical vacuum pump of equal action speed was carried out, the results of which demonstrated the significant efficiency of using the first machine. It has been established that the specific power consumption in the process of transporting plant powders is 20-25% lower with the same speed of action. An economic calculation demonstrates the effectiveness of using a new design of the developed vacuum pump in the technological process of fine grinding of dry plant products due to the vacuum removal of a given grinding fraction. Therefore, the developed pump is recommended to be used for grinding dry bulk plant products at large processing enterprises of the agro-industrial complex, food, pharmaceutical and perfumery industries.

Discriminative correlation tracking based on spatial attention mechanism for low-resolution imaging systems

Low-resolution images are characterized by blurring, less texture information, and lack of detail. Visual object tracking for low-resolution imaging systems remains a challenging task. In this paper, we propose a discriminative correlation tracking algorithm based on a spatial attention mechanism for low-resolution imaging systems (LSDCT) to address these challenges. The key innovations of our proposed algorithm include adjustable windows and a spatial attention mechanism. We design a generic adjustable window to mitigate boundary effects and employ the spatial attention mechanism to highlight the target in low-resolution images. We conduct qualitative and quantitative evaluations on three well-known benchmark datasets: OTB100, TC128, and UAV123. Extensive experimental results indicate that the proposed approach is superior to state-of-the-art trackers.

Rotor Faults Diagnosis by Adjustable Window Function

Rotor Faults Diagnosis by Adjustable Window Function

Window Functions with a Quasi-Rectangular Spectrum

The discrete Fourier transform (DFT) is carried out on a bounded time interval, which is equivalent to multiplying a signal under analysis by a rectangular window whose spectrum has the largest (among the other windows) side lobes. As a result, the effect called spectral leakage occurs. Multiplying the signal by the smoothing window reduces the splatter of its spectral components. There are several dozen variants of window functions as the DFT is used in a variety of problems. Of particular interest is the unique flat-top window, which is employed in broadband applications. In this study, we propose a new adjustable window with a quasi-rectangular spectrum and a method to reduce the level of the spectrum’s side lobes.

A new Evolutionary Structural Optimization method and application for aided design to reinforced concrete components

The Evolutionary Structural Optimization (ESO) has been applied to find the optimal structural topology for design and construction purposes. However, its efficiency is low due to the imperfect deletion criteria. This paper presents an improved elimination criterion and the Windowed Evolutionary Structural Optimization (WESO) method. The former considers the structural average strain energy as the elimination criteria in the optimization, with the elimination rate set as a self-adaption state by an adjustable window. Thus, the problems of low optimization efficiency and distorted optimization results in the traditional ESO can be solved to a certain extent. The WESO method can then be extended and applied with a complex finite element model. It is found that the method has better optimal ability in handling discrete elements in vast structures. Compared with the other method, the WESO method has high computational efficiency and offers more stable and reliable topology than the Michell theoretical solution. Lastly, upon developing the optimal topology for a double-deck structure, it is shown that the WESO method has a great potential in civil engineering applications.

Fund accounting and government-wide financial reporting during the Pre-IPSAS implementation era from a Nigerian experience

PurposeThis paper assessed accuracy level in accounting for government funds in Nigeria's federal treasury and their faithful presentation in government financial reporting. It aimed to determine whether the reported annual balances in Nigeria's financial reporting were reliable or otherwise. Data used in analysis were obtained from secondary sources from federal treasury.Design/methodology/approachEx-post “facto” analysis method was adopted in the study involving the use of statistical techniques of absolute or aggregate mean percentage error derived from differences between recomputed and published fund balances and was employed. This was augmented with interactive review meetings of the initial case research report with the management of Nigeria's audit agency.FindingsResults distilled from the consolidated revenue fund (CRF), development fund and public debt show that recomputed values were greater than the fund balances in the gazetted financial statements. Results for contingency fund (CTF), federation account fund (FAF), special trust fund (STF) and sundry deposit fund yield equal figures and accurate. The paper concludes that there were serial understatements of the core public fund balances in the financial statements over the years. This trend of reporting incorrect in three core public funds in financial statements rendered Nigeria's financial position unreliable in the affected years for decisions. It also facilitated frauds, mismanagement of funds and corrupt practices.Research limitations/implicationsThe scope of the research is restricted to assessment of degree of accuracy in fund accounting, faithful representation of the respective fund balance in the liabilities side of FGN balance sheet and the reliability of the financial position. But, it did not consider or cover the implementation of International Public Sector Accounting Standards (IPSASs) in federal treasury since FGN had not issued any full IPSAS–oriented financial statements as on 2015.Practical implicationsIdentification of deficiencies in fund account balances, structural defects in fund accounting and acts of understatement of carrying balances in CRF and capital development fund (CDF) implies that the aggregate core fund liabilities reported in financial statement of government entities without corresponding assets do not actually reflect a true and fair financial position in some countries. It reveals remarkable degree of financial information asymmetry in government financial reporting. Illusionary fund accounting has direct linkage to poor fiscal governance in many sovereign with associated sub-optimal delivery of public goods and service level distress syndrome in many economies; lead to poverty, unemployment, crisis and macroeconomic disturbances.Social implicationsThe study contributes to the development of fund accounting system; strengthening government financial reporting architecture and practices. It provides framework for tracking financial information asymmetry in government financial reporting and mismanagement of public funds. It provides platform to effect necessary adjustment (correction) during the “first time 3-year adoption” adjustment window in Nigeria. Flowing from the findings, it advocates for institutionalization of government fund accounting standards and provides evidence for migration to accrual accounting system in countries that have not already implemented it. Evaluation system developed herein will improve fund management in federal treasury and contribute to efficient public financial management, good governance and enhance development of public accounting practice.Originality/valueThis exploratory empirical research is the one to ever evaluate accuracy level of fund accounting in sovereign entities and faithful representation in government's financial position prior to implementation of accrual accounting and financial reporting. The study established substantial level of illusionary accounting for public funds and information asymmetry in published government's financial reporting. It is necessary to rectify these discrepancies in fund accounting and financial reporting prior to and or during the first three years of the IPSAS transition implementation programme. These research deliverables provide adopters with relevant data for adjustment accounting during the transition period in strengthening public financial reporting in order to realize the benefit of full IPSAS accrual accounting.

Study and Application on Statistic Power Flow Index

Power grid control center safeguards the bulk power system by monitoring active power flow and managing network congestions. By far, EMS only provided two-dimensional visualized power flow chart, which focused on the power flow limits and real-time monitoring. This paper suggested a multidimensional statistic Power Flow Index (PFI) which was able to analyze, forecast and evaluate grid reliability based on the date mining of operating parameters. PFI helped to discover the potential congestion and enhanced the efficiency of power transmission by plotting power flow distribution curve. By using adjustable time windows and multi-level facility load factors, it is suitable for long-term statistical analysis of different facilities. PFI was one of the essential tools of self-optimal East China Smart Power Grid.

Tunable microwave dielectric properties in SrO‐V2O5 system through compositional modulation

AbstractAdjustment on resonance frequency stability against the sintering temperature of Sr3V2O8 was realized by adjusting the Sr:V mole ratio. Effects of Sr:V ratio on sintering behavior and dielectric properties of Sr3V2O8 were studied. The sintering temperature was sucessfully reduced to 950°C from 1150°C. With increasing vanadium content, both relative permittivity and quality factor decreased, while the temperature coefficient of resonance frequency shifted from positive to negative values. Especially, a near‐zero τf of −1.1 ppm/°C along with a low permittivity (εr) of 9.8 and a quality factor Q × f of 24 120 GHz was successfully achieved in Sr3‐yV2O8‐y ceramic (y = 0.6, sintered at 950°C). The wide compositional and processing adjustment window, favorable dielectric performances, and good chemical compatibility with silver render Sr3‐yV2O8‐y ceramics potential candidates in multilayer electronic devices.