Estimation for a Partial-Linear Single-Index Model

In this paper, we study the estimation for a partial-linear single-index model. A two-stage estimation procedure is proposed to estimate the link function for the single index and the parameters in the single index, as well as the parameters in the linear component of the model. Asymptotic normality is established for both parametric components. For the index, a constrained estimating equation leads to an asymptotically more efficient estimator than existing estimators in the sense that it is of a smaller limiting variance. The estimator of the nonparametric link function achieves optimal convergence rates; and the structural error variance is obtained. In addition, the results facilitate the construction of confidence regions and hypothesis testing for the unknown parameters. A simulation study is performed and an application to a real dataset is illustrated. The extension to multiple indices is briefly sketched.Comment: 43 pages and 2 figure

Performance Analysis of Position Tracking Control With PID Controller Using An Improved Optimization Technique

An Electro-Hydraulic Actuator (EHA) system is usually utilized in production industry such as automotive industry which requires precision, high force and long operating hours. When dealing with the production of engineering parts that require precision, high force and long operating hours, a controller is usually required. It is observed from the literature, an appropriate tuning technique is essential in order to obtain optimal controller’s performance. Therefore, a computational tuning technique, namely Priority-based Fitness Particle Swarm Optimization (PFPSO) is proposed to obtain the parameters of the Proportional-Integral-Derivative (PID) controller in this paper. The performance of the EHA system will be evaluated and compared based on the priority characters of the PFPSO tuning technique, which included settling time and overshoot percentage that affect the output results of the EHA system. As a result, it is observed that the priority based on settling time produced a better result, which enhances the steady-state performance of the EHA system that fulfills the requirement of the precision contro

Mechanical characterisation of nanocrystalline graphite using micromechanical structures

Conductive nanocrystalline graphite has been deposited using plasma-enhanced chemical vapour deposition at 750 °C, directly onto silicon substrates without any catalyst and fabricated into micromechanical membrane and beam structures. Using the buckling profile of the membrane and beam structures, we measure a built-in strain of - 0.0142 and through wafer-bow measurement, a compressive stress of 436 MPa. From this we have calculated the Young's modulus of nanographite as 23.0 ± 2.7 GPa. This represents a scalable method for fabricating nanographite MEMS and NEMS devices via a microfabrication-compatible process and provides useful mechanical properties to enable design of future devices

Potential antioxidant properties of pigmented rice from Sabah, Malaysia

In this study, the methanolic crude extracts of four Sabah rice varieties namely black, red, brown and white rice were screened for their total phenol acids content, tocopherol content, antioxidant and free radical scavenging properties. The red rice contained the highest quantity of phenolic acids (329.93 ± 19.17 mg/100 g) and tocopherols (200.33 ± 13.61 mg/100 g). To detect antioxidant activity of the pigmented rice extracts, ferric thiocyanate (FTC) assay was used and compared with the thiobarbituric acid (TBA) method. Scavenging activity was measured by 2, 2-diphenyl-1-picrylhydrazyl(DPPH) radicals. Red rice extract showed the highest activity for all the three tests, FTC (0.302), TBA (0.329) and DPPH(65.54% ± 0.57) due to its high content of phenolic acids and tocopherols. The results indicate that the pigmented rice varieties possess protective effects against the generation of hydroperoxide and free radical scavenging activity. The antioxidant activity of the extracts differed and was dependent on the bran color of the rice. The results showed that the antioxidant activity was in the following order: red rice > black rice > brown rice > white rice. In conclusion, antioxidant activity was strongly correlated to the total phenolic acids and tocopherols content

A Five-Year Retroactive Analysis of Cut Score Impact: California’s Proposed Supervised Provisional License Program

A five-year cohort of 39,737 examinees who sat for the California Bar Exam (“CBX”) between 2014-18 was analyzed using a simulation model based on actual exam results to evaluate how the minimum passing scores (“cut score”) of 1440, 1390, 1350, 1330, and 1300, if used as qualifying scores for a provisional licensing program, would affect the number of previous examinees, by race and ethnicity, who would qualify to participate within retroactive groupings of five-year, four-year, three-year, two-year, and one-year examinee cohorts.The result of the simulation models indicated that selecting a qualifying score lower than the current California cut score of 1390 will significantly increase both the overall number of eligible participants and the diversity of the group eligible to participate in the proposed alternate licensing program.This study follows an initial study of 85,727 examinees of the CBX from 2009-18 titled, Examining the California Cut Score: An Empirical Analysis of Minimum Competency, Public Protection, Disparate Impact, and National Standards that determined maintaining a high cut score does not result in greater public protection as measured by disciplinary statistics, but does result in excluding minorities from admission to the bar and the practice of law at rates disproportionately higher than Whites

Examining the California Cut Score: An Empirical Analysis of Minimum Competency, Public Protection, Disparate Impact, and National Standards

The selection of a minimum bar exam passing score (“cut score”) shapes the representation of racial and ethnic minorities in the legal profession and the quality of access to justice in the state. California and national policy makers have not had the benefit of detailed exam performance data that analyzes the effect of the cut score on race and ethnicity. Because policy makers consider the cut score an important public protection mechanism, this study also explored whether the selection of higher cut scores better protected the public from attorneys who do not have the minimum competence to practice law. To conduct the analysis, the study used two data sets. The first data set included 85,727 examinees who sat for 21 administrations of the CBX from 2009-18 and the race and ethnicity of each examinee. The second data set included the ABA discipline data from up to 48 U.S. jurisdictions from 2013-18 and the cut scores in each jurisdiction. Using the first data set,the study determined how the selection of a minimum cut score (1) widens or narrows the racial and ethnic impacts of the bar exam and/or (2) alters the racial and ethnic composition of new attorneys joining the legal profession. Both historical actual and simulated cut scores were analyzed. Using the second data set, this study examined a third factor: the relationship, if any, between minimum cut scores and rates of attorney discipline. This analysis determined that initial and eventual passing rates differed significantly between racial and ethnic groups, and this gap was wider at higher simulated cut scores. A simulation analysis using actual examinee scores confirmed that selecting a lower cut score would have significantly narrowed the achievement gap between Whites and racial and ethnic minorities and would have increased the number of newly admitted minority attorneys in California. For example, at 1440, the achievement gap between Whites and Blacks was 27.4 percentage points. But at a simulated cut score of 1300, the achievement gap between these two groups would have been only 14.5 percentage points. This 12.9 percentage point difference in the achievement gap at 1440 and 1300 demonstrates a disparate effect of the higher cut scores. Using the second data set about disciplinary statistics, the study determined that no relationship exists between the selection of a cut score and the number of complaints, formal charges, or disciplinary actions taken against attorneys in the jurisdictions studied. California’s recent decision to lower the cut score from 1440 to 1390 moved California from having the second-highest cut score to the fourth-highest cut score in the country. However, the report data established that at 1390 California will continue to produce significantly disparate pass rates on the basis of race and ethnicity when compared to the national norm of 1350, the New York standard of 1330, and the simulated model of 1300. This study establishes that maintaining a high cut score does not result in greater public protection as measured by disciplinary statistics but does result in excluding minorities from admission to the bar and the practice of law at rates disproportionately higher than Whites

Monolithic Silicon Probes with Flexible Parylene Cables for Neural Prostheses

This work presents the first parylene-insulated silicon probes, which are used for neural prostheses to record high-level cognitive neural signals. With parylene technology, our probes have several advantages compared with the current devices. First, instead of inorganic materials (e.g. silicon dioxide, silicon nitride), the electrodes and conduction traces on the probes are insulated by parylene, an easily-deposited polymer with mechanical flexibility and biocompatibility. As a result, the probes exhibit better electrical and mechanical properties. Second, flexible parylene cables are monolithically integrated with the probes, which arm the probes with very high flexibility to be easily assembled to a high density 3-D array and at the same time provide an ideal method to transmit neural signals through skull during chronic recording. The all dry fabrication process and a 4 X 4 probe array (64 electrodes) were demonstrated. The probes were successfully tested electrically and mechanically in rat cortex. Neural signals were properly recorded

Improved Third Order PID Sliding Mode Controller for Electrohydraulic Actuator Tracking Control

An electrohydraulic actuator (EHA) system is a combination of hydraulic systems and electrical systems which can produce a rapid response, high power-to-weight ratio, and large stiffness. Nevertheless, the EHA system has nonlinear behaviors and modeling uncertainties such as frictions, internal and external leakages, and parametric uncertainties, which lead to significant challenges in controller design for trajectory tracking. Therefore, this paper presents the design of an intelligent adaptive sliding mode proportional integral and derivative (SMCPID) controller, which is the main contribution toward the development of effective control on a third-order model of a double-acting EHA system for trajectory tracking, which significantly reduces chattering under noise disturbance. The sliding mode controller (SMC) is created by utilizing the exponential rule and the Lyapunov theorem to ensure closed-loop stability. The chattering in the SMC controller has been significantly decreased by substituting the modified sigmoid function for the signum function. Particle swarm optimization (PSO) was used to lower the total of absolute errors to adjust the controller. In order to demonstrate the efficacy of the SMCPID controller, the results for trajectory tracking and noise disturbance rejection were compared to those obtained using the proportional integral and derivative (PID), the proportional and derivative (PD), and the sliding mode proportional and derivative (SMCPD) controllers, respectively. In conclusion, the results of the extensive research given have indicated that the SMCPID controller outperforms the PD, PID, and SMCPD controllers in terms of overall performance.