Angular responsivity of ground and space-based direct solar irradiance radiometers

The angular response setup of PMOD/WRC was modified to facilitate measurements of the narrow field of view of radiometers for direct solar irradiance. First, The pointing of the JTSIM-DARA radiometer was measured four times during its construction in the optic laboratory of PMOD/WRC. The final offset of the pointing before shipping relative to the optical axis, defined by a removable alignment cube, is 1.07° / 0.67° (β/γ-axis) for the four-quadrant sensor and 0.095°/-0.017° for the radiometer cavity A. Next to JTSIM-DARA the DARA for the occulter of the satellite Proba-3 was characterised at PMOD/WRC. First tests of the pointing have been carried out and the final pointing characterization will be carried out in summer 2021. Finally, the angular response setup was also used the angular responsivity of solar direct irradiance filter radiometers. The first test was carried out using Precision Filter Radiometer (PFR) F-064.

A Frequency and Voltage Coordinated Control Strategy of Island Microgrid including Electric Vehicles

Frequency and voltage deviation are important standards for measuring energy indicators. It is important for microgrids to maintain the stability of voltage and frequency (VF). Aiming at the VF regulation of microgrid caused by wind disturbance and load fluctuation, a comprehensive VF control strategy for an islanded microgrid with electric vehicles (EVs) based on Deep Deterministic Policy Gradient (DDPG) is proposed in this paper. First of all, the SOC constraints of EVs are added to construct a cluster-EV charging model, by considering the randomness of users’ travel demand and charging behavior. In addition, a four-quadrant two-way charger capacity model is introduced to build a microgrid VF control model including load, micro gas turbine (MT), EVs, and their random power increment constraints. Secondly, according to the two control goals of microgrid frequency and voltage, the structure of DDPG controller is designed. Then, the definition of space, the design of global and local reward functions, and the selection of optimal hyperparameters are completed. Finally, different scenarios are set up in an islanded microgrid with EVs, and the simulation results are compared with traditional PI control and R(λ) control. The simulation results show that the proposed DDPG controller can quickly and efficiently suppress the VF fluctuations caused by wind disturbance and load fluctuations at the same time.

Visual world eyetracking using WebGazer.js

The visual world paradigm is one of the most influential paradigms to study real-time language processing. The present study tested whether visual world studies can be moved online, using PCIbex software (Zehr & Schwarz, 2018) and the WebGazer.js algorithm (Papoutsaki et al., 2016) to collect eye-movement data. Experiment 1 was a fixation task in which the participants looked at a fixation cross in multiple positions on the computer screen. Experiment 2 was a web-based replication of a visual world experiment by Dijkgraaf, Hartsuiker and Duyck (2017). Firstly, both experiments revealed that the spatial accuracy of the data allowed us to distinguish looks across the four quadrants of the computer screen. This suggest that the spatial resolution of WebGazer.js is fine-grained enough for most visual world experiments (which typically involve a four-by-four quadrant-based set-up of the visual display). Secondly, both experiments revealed a delay of roughly 300 ms in the time course of the eye movements, most likely caused by the internal processing speed of the browser or WebGazer.js. This delay can be problematic in studying questions that require a fine-grained temporal resolution and requires further investigation.

Quadrant Mapping Artificial Lift Concept

This paper outlines a concept for monitoring performance of artificial lift performance such as electrical submersible pump (ESP), hydraulic pumping unit (HPU), sucker rod pump (SRP) and progressive cavity pump (PCP), for a large number of wells. The objective is to generate simplified monitoring performance of artificial lift with a huge number of wells on one page by creating quadrant mapping consisting of two coordinates with x axis representing pump efficiency and y axis showing pump submergence. We made a four-quadrant limit by pump efficiency (50%) and submergence (200 m). Optimum wells will show on range pump efficiency above 50% and submergence below 200 m, and 3 other quadrants are classified as artificial lift problems, well potential and sizing/design problems. By using the quadrant mapping concept, we can generate performance of artificial lift for 1500++ wells in one page, and this mapping consists of four quadrants (quadrant 1, quadrant 2, quadrant 3 and quadrant 4), quadrant 1 (Submergence above 200 meter and lifting efficiency below 50%) showing wells which have artificial lift problem, quadrant 2 (Submergence is above 200 meters and efficiency is above 50%) showing well which have potential to increased production, quadrant 3 (Submergence is below 200 meters and efficiency is above 50%) showing the optimum wells operation and quadrant 4 (Submergence is below 200 meters and efficiency is below 50%) showing the wells which required to re-sizing/re-design artificial lift. This quadrant mapping can be shown to Engineers, manager's and shareholder to show overall performance and classification detailed problems to create a troubleshooting, optimization program to increased oil production, run life artificial and result in better production performance. This mapping also helps petroleum engineers to get a better field view and create priorities and program optimization based on the quadrant mapping result and classification.

STUDY ON PROPULSIVE PERFORMANCE OF TWO GEOMETRICALLY SIMILAR PODDED PROPULSORS

This paper presents the outcome of a research to evaluate the effect of size on the propulsive performance of podded propulsors in cavitating and non-cavitating open water conditions. Two cases are examined, namely: propeller-only case and pod-unit case. In the propeller-only case, a commercial propeller dynamometer is used to measure the thrust and torque of two propellers of different size at the four quadrants of propellers with varied shaft and flow speeds. Also, both propellers are tested at different tunnel pressure to study and compare the behaviour under similar cavitation conditions. In the pod-unit case, two geometrically similar but different sized pod-units are tested using two separate custom-made pod dynamometer systems in two towing tank facilities in straight-ahead and static azimuthing conditions. The study showed that the performance characteristics stabilize at lower Reynolds Number for the smaller propeller than the larger propeller. The propulsive performance of the two propellers was comparable in the four-quadrant experiments. Also, the experiments at the cavitating conditions showed that the cavitation characteristics of the two propellers were consistent at corresponding operating conditions. The experiment results of the two pod-units were also comparable for forces and moments in the three coordinate directions in the straight-ahead and static azimuthing conditions. A brief discussion on the uncertainty assessments for each of the measurements is also presented.

Research on Solar Power Generation Control System Based on 360 Degree Rotate Double-Motor

Aiming at the problems of low utilization rate of solar energy and poor anti-interference ability of tracking structure solar energy control system in fixed structure solar energy device, this paper designs a dual axis high-precision solar tracking system based on four quadrant rule. The system adopts two ways: automatic tracking and manual correction. The system uses four photoresistors as detection elements, uses the four quadrant principle to judge the tracking offset angle, and drives two-dimensional two axis stepper motor through STC89C52 processor to achieve the purpose of vertical angle, so as to ensure that the solar panel is always in the state of maximum light receiving surface; When the system is disturbed, it can be judged according to the change of the photosensitive resistance in the energy monitoring system, and the artificial correction can be realized by modulating the size of the divider resistance, which can basically achieve 360° Automatic rotation tracking. In addition, the energy monitoring system based on LabView is designed. Through the real system analysis, it can be concluded that the photoelectric energy conversion rate of the fixed solar device is increased by 32.4%.

Concordance rate of a four-quadrant plot for repeated measurements

Background To assure the equivalence between new clinical measurement methods and the standard methods, the four-quadrant plot and the plot’s concordance rate is used in clinical practice, along with Bland-Altman analysis. The conventional concordance rate does not consider the correlation among the data on individual subjects, which may affect its proper evaluation. Methods We propose a new concordance rate for the four-quadrant plot based on multivariate normal distribution to take into account the covariance within each individual subject. The proposed concordance rate is formulated as the conditional probability of the agreement. It contains a parameter to set the minimum concordant number between two measurement methods, which is regarded as agreement. This parameter allows flexibility in the interpretation of the results. Results Through numerical simulations, the AUC value of the proposed method was 0.967, while that of the conventional concordance rate was 0.938. In the application to a real example, the AUC value of the proposed method was 0.999 and that of the conventional concordance rate was 0.964. Conclusion From the results of numerical simulations and a real example, the proposed concordance rate showed better accuracy and higher diagnosability than the conventional approaches.

Exploring Pupil Position as An Eye-Tracking Feature for Four-Class Emotion Classification In VR

This paper presented a preliminary investigation of a novel approach on emotion recognition using pupil position in Virtual Reality (VR). We explore pupil position as an eye-tracking feature for four-class emotion classification according to the four-quadrant model of emotions via a presentation of 360° videos in VR. A total of ten subjects participated in this emotional experiment. A 360° video with four sessions of stimulation of emotions will be presented in VR to evoke the user’s emotions. The eye data were recorded and collected using Pupil Labs eye-tracker and the emotion classification was done by using pupil position solely. The classifier used in this investigation is the Support Vector Machine (SVM) machine learning algorithm. The results showed that the best accuracy achieved from this four-class random classification was 59.19%.