Renewable energy allocation based on maximum flow modelling within a microgrid

This paper designs an energy allocation scheme based on maximum flow modeling for a microgrid containing renewable energy generators and consumer facilities. Basically, the flow graph consists of a set of nodes representing consumers or generators as well as a set of weighted links representing the amount of energy generation, consumer-side demand, and transmission cable capacity. The main idea lies in that a special node is added to account for the interaction with the main grid and that two-pass allocation is executed. In the first pass, the maximum flow solver decides the amount of the insufficiency and thus how much to purchase from the main grid. The second pass runs the flow solver again to fill the energy lack and calculates the surplus of renewable energy generation. The performance measurement result obtained from a prototype implementation shows that the generated energy is stably distributed over multiple consumers until the energy generation reaches the maximum link capacity.

Analysis of conductive olfactory dysfunction using computational fluid dynamics

Conductive olfactory dysfunction (COD) is caused by an obstruction in the nasal cavity and is characterized by changeable olfaction. COD can occur even when the olfactory cleft is anatomically normal, and therefore, the cause in these cases remains unclear. Herein, we used computational fluid dynamics to examine olfactory cleft airflow with a retrospective cohort study utilizing the cone beam computed tomography scan data of COD patients. By measuring nasal–nasopharynx pressure at maximum flow, we established a cut-off value at which nasal breathing can be differentiated from combined mouth breathing in COD patients. We found that increased nasal resistance led to mouth breathing and that the velocity and flow rate in the olfactory cleft at maximum flow were significantly reduced in COD patients with nasal breathing only compared to healthy olfactory subjects. In addition, we performed a detailed analysis of common morphological abnormalities associated with concha bullosa. Our study provides novel insights into the causes of COD, and therefore, it has important implications for surgical planning of COD, sleep apnea research, assessment of adenoid hyperplasia in children, and sports respiratory physiology.

Determination of the Most Interconnected Sections of Main Gas Pipelines Using the Maximum Clique Method

This article is devoted to the definition of the most important combinations of objects in critical network infrastructures. This study was carried out using the example of the Russian gas transmission network. Since natural gas is widely used in the energy sector, the gas transmission network can be exposed to terrorist threats, and the actions of intruders can be directed at both gas fields and gas pipelines. A defender–attacker model was proposed to simulate attacks. In this model, the defender solves the maximum flow problem to satisfy the needs of gas consumers. By excluding gas pipelines, the attacker tries to minimize the maximum flow in the gas transmission network. Russian and European gas transmission networks are territorially very extensive and have a significant number of mutual intersections and redundant pipelines. Therefore, one of the approaches to inflicting maximum damage on the system is modeled as an attack on a clique. A clique in this study is several interconnected objects. The article presents the list of the most interconnected sections of main gas pipelines, the failure of which can cause the greatest damage to the system in the form of a gas shortage among consumers. Conclusions were drawn about the applicability of the maximum clique method for identifying the most important objects in network critical infrastructures.

Rapidly Deployable Algae Cleaning System for Applications in Freshwater Reservoirs and Water Bodies

Occurrence of large-scale harmful algal blooms (HABs) in our reservoirs and water bodies threaten both quality of our drinking water and economy of aquaculture immensely. Hence, rapid removal of HAB biomass during and after a bloom is crucial in protecting the quality of our drinking water and preserve our water resources. We reported here a rapidly deployable algae cleaning system based on a high-capacity high-throughput (HCHT) spiral blade continuous centrifuge connected with inlet and effluent water tanks and a series of feed-in and feed-out pumps as well as piping, all fitted into a standard 20 feet metal shipping container. The system separates algal biomass from algae-laden water with a maximum flow rate of 4000 L/h and a centrifugal force of 4500× g. Cells collected by the system are still intact due to the low centrifugal force used. We showed that after HCHT centrifugation, cellular contents of HAB biomass were not found in the effluent water, and hence, could be discharged directly back to the water body. Furthermore, the addition of flocculants and chemicals prior to the separation process is not required. The system could operate continuously with proper programmed procedures. Taken overall, this system offered a much better alternative than the traditional flocculation- and sonication-based methods of HAB removal in a freshwater environment. This deployable system is the first of its kind being built and had been field-tested successfully.

Prostate-Specific Antigen Velocity Predicts Surgical Outcome of Thulium Laser Enucleation of the Prostate

Background: We determined the effect of prostate-specific antigen velocity (PSAV) on the surgical outcome of thulium laser enucleation of the prostate (ThuLEP) in patients with benign prostatic hyperplasia (BPH).Methods: A retrospective review was performed of prospectively collected data of patients with BPH who underwent ThuLEP at any time from 2017 to 2019. Patients who had undergone BPH surgery or had prostate cancer previously were excluded, and patients with prostate-specific antigen (PSA) > 4 ng/ml were examined through transrectal ultrasound-guided prostate biopsy to rule out prostatic malignancy. Furthermore, patients were excluded if prostatic malignancy was diagnosed during postsurgery follow-up.Results: The PSA level, International Prostate Symptom Score (IPSS), and quality of life (QoL) of 27 male patients at 3 and 15 months postsurgery differed significantly from those at presurgery; the maximum flow rate (Qmax) and postvoid residual (PVR) significantly differed between 3 months postsurgery and presurgery; and 22 and 5 patients had good to excellent and fair to poor outcomes, respectively, at 15 months postsurgery. Patients were divided into two groups (fair and poor vs. good and excellent outcomes at 15 months postsurgery), which significantly differed with respect to PSAV at 3 months postsurgery (P = 0.04), IPSS presurgery (P < 0.02), surgical length (P = 0.01), and hospitalization duration (P = 0.04). In a receiver operating characteristic (ROC) analysis, the optimal cutoff value of PSAV of −0.52 ng/ml characterized effectiveness at 15 months after ThuLEP, and the area under the curve (AUC), sensitivity, and specificity were 0.82 (P < 0.02), 0.80, and 0.82, respectively. For PSAV < -0.52 and ≥-0.52 ng/ml, the percentages of reduction for IPSS, QoL, Qmax, and PVR were −78.6 and −71.4%, −33.3 and 0.0%, 94.4 and 40.0%, and −85.1 and −38.7%, respectively.Conclusions: Postsurgical PSAV was positively correlated with surgical success, and the PSAV cutoff was −0.52 ng/ml. PSAV can, thus, be used to guide the postsurgical follow-up treatment at 3 months after BPH surgery.

Gamification of Formative Feedback in Language Arts and Mathematics Classrooms

The use of computer games in education has been increasing in popularity during the past decade. Game-based learning environments are designed to teach specific knowledge content and skill-based learning outcomes using game elements. One main reason for using game-based learning environments is to increase student motivation and engagement while teaching learning outcomes. Many of the game-based learning environments are designed so that students will reach maximum flow, which is defined as students being so completely immersed in that game that they do not notice that they are learning. These learning environments have been shown to improve many behaviour and cognitive learning outcomes. While game-based learning has many benefits, some educational researchers have indicated that it is often very costly to develop a complex game-based assessment to teach a few learning outcomes. Hence, in some cases it is more beneficial to approach the use of computer games in education using gamification.

Kalman Filter Implementation of Subglottal Impedance-Based Inverse Filtering to Estimate Glottal Airflow during Phonation

Subglottal Impedance-Based Inverse Filtering (IBIF) allows for the continuous, non-invasive estimation of glottal airflow from a surface accelerometer placed over the anterior neck skin below the larynx. It has been shown to be advantageous for the ambulatory monitoring of vocal function, specifically in the use of high-order statistics to understand long-term vocal behavior. However, during long-term ambulatory recordings over several days, conditions may drift from the laboratory environment where the IBIF parameters were initially estimated due to sensor positioning, skin attachment, or temperature, among other factors. Observation uncertainties and model mismatch may result in significant deviations in the glottal airflow estimates; unfortunately, they are very difficult to quantify in ambulatory conditions due to a lack of a reference signal. To address this issue, we propose a Kalman filter implementation of the IBIF filter, which allows for both estimating the model uncertainty and adapting the airflow estimates to correct for signal deviations. One-way analysis of variance (ANOVA) results from laboratory experiments using the Rainbow Passage indicate an improvement using the modified Kalman filter on amplitude-based measures for phonotraumatic vocal hyperfunction (PVH) subjects compared to the standard IBIF; the latter showing a statistically difference (p-value =0.02, F=4.1) with respect to a reference glottal volume velocity signal estimated from a single notch filter used here as ground-truth in this work. In contrast, maximum flow declination rates from subjects with vocal phonotrauma exhibit a small but statistically difference between the ground-truth signal and the modified Kalman filter when using one-way ANOVA (p-value =0.04, F=3.3). Other measures did not have significant differences with either the modified Kalman filter or IBIF compared to ground-truth, with the exception of H1-H2, whose performance deteriorates for both methods. Overall, both methods (modified Kalman filter and IBIF) show similar glottal airflow measures, with the advantage of the modified Kalman filter to improve amplitude estimation. Moreover, Kalman filter deviations from the IBIF output airflow might suggest a better representation of some fine details in the ground-truth glottal airflow signal. Other applications may take more advantage from the adaptation offered by the modified Kalman filter implementation.

A Prospective Comparative Study of Mobile Acoustic Uroflowmetry and Conventional Uroflowmetry

Purpose: The aim of this study was to assess the performance of a mobile acoustic Uroflowmetry (UFM) application compared with standard UFM in the pediatric population.Methods: A mobile acoustic UFM application represents a noninvasive method to estimate the urine flow rate by recording voiding sounds with a smartphone. Male pediatric patients who were undergoing UFM testing were prospectively recruited, and the voiding sounds were recorded and analyzed. The intraclass correlation coefficient (ICC) was used to compare the maximum flow rate (Qmax), average flow rate (Qavg), voiding time (VT), and voiding volume (VV) as estimated by acoustic UFM with those calculated by standard UFM. Differences in Qmax, Qavg, VT, and VV between the 2 UFM tests were determined using 95% Bland-Altman limits of agreement.Results: A total of 16 male patients were evaluated. Their median age was 9 years. With standard UFM, the median Qmax, Qavg, VT, and VV were 18.7 mL/sec, 11.1 mL/sec, 15.2 seconds, and 157.8 mL, respectively. Strong correlations were observed between the 2 methods for Qmax (ICC=0.755, P=0.005), VT (ICC=0.974, P<0.001), and VV (ICC=0.930, P<0.001), but not for Qavg (ICC=0.442, P=0.135). The Bland-Altman plot showed good agreement between the 2 UFM tests. Flow patterns recorded by acoustic UFM and conventional UFM showed good visual correlations.Conclusions: Acoustic UFM was comparable to standard UFM for male pediatric patients. Further validation of its performance in different toilet settings is necessary for broader use.