Frequency Profile Research Articles

Power system frequency profile improvement using satin bowerbird optimized tilt fractional cascade controller with reduced data based cost function

The objectives of the automatic generation control (AGC) are attained via secondary control mechanism with optimal controller gains. The best solutions of these gains are identified by population search-based algorithms with the help of performance metrices. The controller design issues of AGC treat these performance metrics as a cost function. This paper introduces a new performance measure implemented with dominated samples information extracted from the frequency and tie line power changes. This new integral square error (NISE) is incorporated in fitness function and tested on isolated and multi area interconnected power system scenarios with satin bowerbird optimizer to tune the controller gains. Additionally, integral-tilt proportional-fractional order derivative controller is proposed in this paper and comparisons are made with popular controllers to show the merits in terms of AGC specifications. Optimal gain parameters of all controllers are achieved with existing integral square error and the proposed NISE cost functions and extensive simulations are carried out to illustrate the merits of the work. Studies are also expanded to nonlinear systems in order to evaluate the adaptability, performance improvement, and effectiveness of the suggested cost function, controller, and tuning method.

Achalasia cardia sub-types in children: Does it affect the response to therapy?

Achalasia sub-types affect treatment response in adults, but there is no similar data in children. We studied the differences in clinico-laboratory features and response to therapy between achalasia sub-types in children. Forty-eight children (boys:girls-25:23, 14 [0.9-18] years) with achalasia (clinical, barium, high-resolution manometry [HRM], gastroscopy) were evaluated. The sub-type was determined by Chicago classification at HRM. Pneumatic dilatation (PD) or surgery was the primary therapy. Success was defined as Eckhardt score of ≤ 3. Dysphagia (95.8%) and regurgitation (93.8%) were the most common symptoms. Forty of 48 cases had an adequate HRM study: Type I (n-19), II (n-19) and III (n-2). Types I and II had similar clinical profile. Type II had higher basal lower esophageal sphincter (LES) pressure (30.5 [16.5-46] vs. 22.5 [13-43] mmHg; p = 0.007) and less dilated esophagus on timed barium esophagogram (TBE, 25 [13-57] vs. 34.5 [20-81] mm; p = 0.006) than type I. Both types had similar success (86.6% [13/15] vs. 92.8% [13/14]; p = 1) after first PD and need of post-PD myotomy (5/17 vs. 1/16; p = 0.1) in follow-up. Twenty-three cases had TBE before and after PD; 15 (65.2%) had good clearance. These subjects required myotomy (1/15 vs. 4/8; p = 0.03) and repeat PD (5/15 vs. 4/8; p = 0.08) less often than those with poor clearance on TBE. Types I and II achalasia have similar frequency and clinical profile. Type II has higher LES pressure and less dilated esophagus than Type I. Both respond equally well to initial PD. Type I required post-PD myotomy more often, though not significantly. TBE is useful for assessing therapeutic response.

β Band Rhythms Influence Reaction Times.

Despite their involvement in many cognitive functions, β oscillations are among the least understood brain rhythms. Reports on whether the functional role of β is primarily inhibitory or excitatory have been contradictory. Our framework attempts to reconcile these findings and proposes that several β rhythms co-exist at different frequencies. β Frequency shifts and their potential influence on behavior have thus far received little attention. In this human magnetoencephalography (MEG) experiment, we asked whether changes in β power or frequency in auditory cortex and motor cortex influence behavior (reaction times) during an auditory sweep discrimination task. We found that in motor cortex, increased β power slowed down responses, while in auditory cortex, increased β frequency slowed down responses. We further characterized β as transient burst events with distinct spectro-temporal profiles influencing reaction times. Finally, we found that increased motor-to-auditory β connectivity also slowed down responses. In sum, β power, frequency, bursting properties, cortical focus, and connectivity profile all influenced behavioral outcomes. Our results imply that the study of β oscillations requires caution as β dynamics are multifaceted phenomena, and that several dynamics must be taken into account to reconcile mixed findings in the literature.

Epidemiological Profile of traumatic spinal cord injuries in the National Referral Hospital, Bhutan

Introduction: The number of traumatic spinal cord injuries associated with a fracture is on rise which is compounded by rise in number of motor vehicle accidents in the country. The aim of the study was to assess frequency, cause, pattern, and demographic profile of traumatic spinal cord injuries in the Bhutanese population. Methods: A retrospective study was conducted at National Referral Hospital from 2018 to 2020. Hospital records of patients, treated for traumatic spinal cord injury were reviewed. Results: Of the total of 100 patients with traumatic spinal injury admitted during study period, there were 69 males (69%) and 31 females (31%). The mean age was 44.18 years (±16.625 SD). Falls (61%) was most common cause of spine injury followed by road traffic accident (27%). Lumbar spine injury was most common (42%) followed by cervical spine (31%) and thoracic spine (23%) injuries. Of 100 patients with spinal injury 63 patients did not have associated cord injuries while 37% of patients had associated spinal cord injuries and of those with spinal injuries, 20% of them had complete spinal cord injury (SCI) and 17% had incomplete SCI. Regarding treatment, 42% of spine injury patients underwent surgical procedures while 58% were managed conservatively. The mean length of hospital stay after spinal injury was 6.62 days (± 26.06 SD, range 1-215). Conclusions: The study found that most common cause of spine and associated cord injuries were falls followed by road traffic accidents. By collaborating with traffic and road safety division, our study findings have potential to significantly reduce road traffic accidents and enhance preventive measures. Additionally, we can provide valuable education to families regarding rehabilitation and social support, ultimately leading to improved outcomes and better quality of life for individuals living with spinal cord injuries.

Spotting Interface Structuring during Na‐Insertion into the NaSICON Na3V2(PO4)3 by EQCM and Operando Fiber Optic Infrared Spectroscopy

AbstractReliable operation of Na‐ion batteries requires a mastering of the interfacial processes governing intercalation kinetics. Ion desolvation, amongst others, is a crucial phenomenon as far as power applications are envisioned. Studying the intricacies of interfacial processes faces experimental challenges. Here the complementary use of electrochemical quartz crystal microbalance (EQCM) and operando infrared fiber evanescent wave spectroscopy (IR‐FEWS) combined with molecular dynamics (MD) simulations is reported to investigate the electrode/electrolyte interface of polyanionic Na‐insertion compounds Na3V2(PO4)3 (NVP) and Na3V2(PO4)2F3 (NVPF). Through screening of various electrolytes that differ in their solvation energy and viscosity, the existence of an unusual mass uptake/depletion signal is demonstrated at the NVP interfaces only, indicative of a dissimilarity in migration kinetics of solvent molecules between NVP and NVPF interfaces as supported by IR‐FEWS. This finding is rationalized by positing that sodium depletion is caused by the unusually rapid ion diffusion within NVP mediated by an intermediate metastable phase, which leads to opposite Na+ concentration and free solvent molecule gradients at the interface that causes the unusual and anomalous feature observed on EQCM frequency profiles. This feature does not appear with NVPF showing lower ionic diffusion. Altogether, this fundamental study provides valuable fundamental insights into the interface structuring of insertion compounds depending upon their Na+ mobility.

A case study of mesospheric frontal interaction and associated processes over the western Himalaya

An interesting event of interaction between a mesospheric bore and a front is observed in O(1S) 557.7 nm airglow images over the western Himalayan region on the night of 25 April 2022. The event is unique as it is the first report of a mesospheric bore interacting with a typical mesospheric front. The vertical profiles of temperature and Brunt Vaisala frequency indicate presence of a strong mesospheric inversion layer (MIL) which acts as a stable thermal duct for propagation of the mesospheric bore. Chemical heating is believed to be a causative mechanism for sustaining such strong MIL/thermal duct, although the presence of Doppler duct could not be verified due to a lack of wind measurement. The bore front shows an anti-clockwise rotation with time which is attributed to the differential phase speed between the extreme parts of the bore due to variation of duct depth. The bore propagation above is believed to push the underlying OH layer downward, resulting in a maximum horizontal slope of the peak height of the OH volume emission rate (VER) on the event day. The results highlight the characteristics of bore-front interaction, bore propagation supported by the thermal duct, and its effect on the vertical displacement of the airglow emission layers.

An optimal frequency regulation in interconnected power system through differential evolution and firefly algorithm

Automatic generation control is extensively used to regulate power plants in a modern area of the power system network. In this paper, automatic generation and frequency control in interconnected power system is presented. A multisource such as thermal, hydro, and gas-based power plant is considered in this study, which is carried out by incorporating nonlinearity like generation rate constants, HVDC link, and the conventional PID controller design. Further, an optimal setting of the PID controller is performed by employing evolutionary, and metaheuristic algorithm-based approaches such as differential evolution and firefly algorithm, respectively. With these algorithms, the proposed model has been tested with their performance evaluation and comparison characteristics are discoursed. The robustness of the proposed controllers is assessed based on comparative analyses to regulate the interconnected power network’s frequency profile under different loading conditions. The stability analysis is performed using the Eigen and Nyquist plots to assess the proposed controllers’ efficacy. Besides, the frequency control study is summarized with comparative assessment through various performance indices such as settling time, peak overshoot and undershoots under different operating conditions. Finally, the proposed control scheme, in the interconnected power system, is validated through a real-time digital simulation platform, i.e., OPAL-RT 5142. The comparison of simulation and real-time results demonstrates the effectiveness of the FA-optimized PID controller in comparison with that of the DE-optimized PID controller.

Frequency and Clinical Profile of Cardiac Arrhythmias and its Immediate Outcome in Children at Tertiary Care Hospital

Objective: To determine the frequency and clinical profile of arrhythmia and its immediate outcome in children presenting to a tertiary care center. Study Design: A cross-sectional study. Duration and place of study: July 2021 to June 2022, the National Institute of Cardiovascular Diseases, Karachi. Methodology: A total of 100 children of both gender , ranging in age from 1 day to 18 years, who presented with the symptoms of syncope, decreased or increased heart rate, chest discomfort, breathlessness were included in this study. Children who presented with cardiac arrhythmias had varying proportions of several criteria of relevance, such as clinical characteristics, age and gender distribution. In patients with unexplained arrhythmias or syncope, a thorough history, general physical exam, and cardiac examinations—including 12-lead electrocardiograms, 2-D echocardiograms, and Holter studies—were conducted. Results: A total of 100 children were included in this study among them 70 children presented with tachyarrhythmia and 30 children presented with bradycardia. The average age was 8.13± 4.45 years. Among the tachyarrythmias group the most frequent initial symptoms recorded in 45 (64.28%) and 15 (21.42%) youngsters, respectively, were palpitation and chest pain. A total of 19 (27.14%) children were discovered to have acyanotic CHDs. SVT was found to be the most common type of arrhythmia in 25 (30.1%) children, followed by ventricular tachycardia and atrial fibrillation in 15 (21.42%) and 10 (14.28%) of the same age groups. A total of 3 (4.28%) of the hospitalized children died. Among the bradycardia group 80% of children were found with complete heart block, 53.3% syncope, 26.7% were asymptomatic, and 20% were with multiple findings of irritability, poor feeding, breathlessness, and syncope. 20% of them developed LV dysfunction. Conclusion: The most frequent presenting symptoms were palpitations and chest discomfort. The other most common types of arrhythmia were supraventricular tachycardia, atrial fibrillation, ventricular tachycardia and bradycardia. Children's hospital stays were generally short and the therapy for arrhythmias had favorable overall results, however, 4.28% of children in the tachyarrhythmia’s group died of heart failure, while there was no expiry in the bradycardia group. Keywords: Arrhythmias, palpitations, supraventricular and ventricular tachycardia, bradycardia and heart Block

Application of artificial hummingbird algorithm in a renewable energy source integrated multi-area power system considering Fuzzy based tilt integral derivative controller

This paper demonstrates the application of a novel artificial hummingbirds’ algorithm (AHA) and fuzzy (F) based tilt-integral-derivative (F-TID) controller in a renewable energy source integrated multi-area power system for the first time. Also, the chest time constant of steam turbine are calculated based sliding pressure mode operation of the superheater and it has been found that the chest time constant of steam turbine depends on plant loading. The system dynamics with the proposed controller are compared to those of existing controllers such as proportional-integral-derivative (PID) and TID, and it is revealed that the system with proposed F-TID controller has better system dynamics. The comparison of system dynamic with F-TID considering grasshopper algorithm (GHA), bird swarm algorithm (BSA) and AHA yield that the system dynamic with AHA outperformed. Further, a Friedman test has been also performed to validate the proposed algorithm. The study on various loading of thermal unit considering sliding pressure mode of operation revealed that, when loading increases toward or above its rated value the system dynamic improves. The effects of dish-stirling-thermal-system (DSTS) and wind-turbine-system (WTS) integration on system performance are also analyzed, and it has been found that the integration of renewable energy sources supports in a generation and it shows approximately 6% improvement in frequency profile along with 8% improvement in tie-power responses. The comparative analysis of system dynamics with AC tie-line, conventional high voltage direct current (HVDC), and accurate model of HVDC link reveals the better dynamics performance of the latter. Furthermore, the robustness of proposed F-TID controller is evaluated by sensitivity analysis and it is inferred that the proposed controller provides stables responses under varied loading condition.

Rogue waves for resonant triads in stratified fluids with a sharply peaked buoyancy frequency profile

Rogue waves for resonant triads in stratified fluids with a sharply peaked buoyancy frequency profile

Coupling to multi-mode waveguides with space-time shaped free-space pulses

Guided wave optics, including most prominently fiber optics and integrated photonics, very often considers only one or very few spatial modes of the waveguides. Despite being known and utilized for decades, multi-mode guided wave optics is currently rapidly increasing in sophistication in parallel with technological improvements and advancing simulation tools. The physics of multi-mode interactions are usually driven by some initial energy distribution in a number of spatial modes. In this work we introduce how, with free-space input beams having space-time couplings, the different modes can be excited with different complex frequency or time profiles. We cover fundamentals, the coupling with a few simple space-time aberrations, different waveguides, and a number of technical nuances. This concept of space-time initial conditions in multi-mode waveguides will provide yet another tool to study the rich nonlinear interactions in such systems.

Transitivity in Pakistani English: A Corpus-based Approach towards Mapping Frequency Profiles

This paper aims at building frequency profiles based on transitivity patterns of a small number of text corpora belonging to Pakistani English newspaper editorials. The profiles have been built by using UAM Corpus Tool (O’ Donnell, 2008) to explore transitivity features. The empirical analysis then has been compared with the frequency profiles of English language (Matthiessen, 2006 and Stubbs, 1996) to establish common features. The present work draws inspiration by Michael Halliday who is known as one of the pioneer corpus linguists since his early work on the Chinese language (Halliday 1956, cited in Halliday 1993). Mapping his (ibid) study on the BNC model he concluded that the relative frequencies of past and non-past are about 50-50 and the relative frequencies of positive and negative are about 9-1 (reported in Halliday 1993). Similarly, the present study looks closer to Standard English, and this is partially because the editorials are written by professional writers, and are well edited before printing.

Imparting Reprocessability, Quadruple Shape Memory, Self-Healing, and Vibration Damping Characteristics to a Thermosetting Poly(urethane-urea)

The advent of dynamic covalent bond chemistry (DCBC) has sparked renewed research interest in reprocessability of thermosetting polymers. However, combining reprocessability with stimuli-responsiveness remains a challenge for futuristic applications. Usually, a combination of complementary DCBCs is employed to integrate reprocessability with shape memory as well as self-healing (SH) attributes in a single polymeric system. In the present work, we report two-component poly(urethane-urea) (PUU) networks, with varied hard segment (HS) concentrations, that exhibit quadruple shape memory (QSM), efficacious vibration damping, thermally activated intrinsic SH as well as multiple cycles of thermal reprocessability. The component A is an isocyanate capped bi-soft segment blend of polybutadiene diol and polypropylene glycol, while the second component comprises an aromatic diamine chain extender solubilized in an oligomeric polyoxypropylene triol. The networks characterized through FTIR as well as small- and wide-angle X-ray scattering (SAXS and WAXD) revealed a phase-separated morphology with extensive hydrogen-bonding (H-bonding) interactions in the HS domains of the PUU networks. Dynamic mechanical analysis (DMA) measurements revealed broad dissipation factor (tan δ) vs temperature and frequency profiles of the networks, which could be leveraged for efficacious passive vibration damping applications. A dissociative mechanism of urethane and urea bond exchange, evidenced from temperature-dependent FTIR studies enabling facile stress relaxation, is proposed to be the mechanistic origin of the reprocessability and SH of the networks. A broad dissipation factor (tan δ) vs temperature profiles endowed the networks with QSM characteristics. We posit that the study is relevant for expanding the scope of DCBCs for development of reprocessable thermosetting polyurethanes with multiple smart functionalities.

Impact of self-heating on RF/analog and linearity parameters of DMG FinFETs in underlap and overlap configurations

In this paper, the influence of self-heating effect (SHE) on the performance of Silicon on Insulator (SOI) dual material gate (DMG) FinFETs in underlap and overlap configurations for RF/analog applications is reported using three-dimensional TCAD simulators. The increase in electron velocity at channel surface is due to reduce effective electrical field at drain end, resulting in smaller DIBL and hot carrier effects. The device insights are reported by electron velocity, lattice temperature, thermal resistance, and output conductance versus frequency profiles. The findings on analog/RF figures of merit such as transconductance (gm), output conductance (gd), intrinsic gain (Ai), gate capacitance (Cgg), intrinsic delay (τ), cut-off frequency (fT), transconductance generation factor (TGF), gain frequency product (GFP), transconductance frequency product (TFP), and gain transconductance frequency product (GTFP) are reported with and without SHE. The results show that analog performance of Conventional and Underlap structures are improved but the influence of SHE is more deteriorating on Overlap structure. Furthermore, the linearity performance parameters VIP2, VIP3, IIP3, and 1 dB compression point are degraded with self-heating is due to increase in gm2 and gm3 values. It is seen that the gate overlap structure exhibits higher ON state performance which even after deterioration with Self-heating is still better than its counterparts as it has better gate controllability stemming from its lower effective channel length.

High-Proficiency L1 and L2 English Learners’ Morphological Words in Writing

English differs from other languages in morphology, which may cause trouble in EFL learning. The interesting topic is whether ESL learners can obtain the same level of morphology in their English learning as native English speakers. The study explores whether high-proficiency EFL learners differ from native EL1 learners in writing using root words, inflected words, and derived words. This article reported on a comparative study between Advanced EFL learners (TOEFL Testees (n = 318)) and native English learners (writers of the Louvain Corpus of Native English Essays (n = 176)) by lexical frequency profile analysis on their use of root words, inflected words, and derived words in writing. The findings suggest that there are significant differences between the two groups. TOEFL writers used a much higher proportion of root words but a much lower proportion of inflected and derived words than native English learners. The findings will expose the differences between EFL learners and native L2 learners in word learning and contribute to L2 language teaching and learning theoretically and practically.

Correlation between resource-generating powers of quantum gates

We analyze the optimal basis for generating the maximum relative entropy of quantum coherence by an arbitrary gate on a two-qubit system. The optimal basis is not unique, and the high quantum coherence generating gates are also typically high entanglement generating ones and vice versa. However, the profile of the relative frequencies of Haar random unitaries generating different amounts of entanglement for a fixed amount of quantum coherence is different from the one in which the roles of entanglement and quantum coherence are reversed, although both follow the beta distribution.

Is there a dose-response relationship between cannabis use and violence? A longitudinal study in individuals with severe mental disorders

IntroductionRecent longitudinal studies point towards the existence of a positive relationship between cannabis use and violence in people with severe mental disorders. However, the existence of a dose-response relationship between the frequency and/or the severity of cannabis use and violence has seldom been investigated.ObjectivesThis study aimed to determine if a dose-response relationship between cannabis use and violence exists in a psychiatric population.MethodsThis observational study was conducted at the Institut universitaire de santé mentale de Montréal (Montréal, Canada). A total of 98 outpatients (81 males and 17 females, all over 18 years of age) with severe mental disorders were included in the analyses. Clinical evaluations were conducted every 3 months for a year. Substance use, violent behaviors, and potential covariables were assessed through self-reported assessments, urinary testing, as well as clinical, criminal, and police records. Using generalized estimating equations, the association between cannabis use frequency (non-users, occasional, regular, and frequent users, assessed using the Time-Line Follow-Back and confirmed with urinary testing) and violence was investigated, as well as the association between the severity of cannabis use (measured using the Cannabis Use Problems Identification Test – CUPIT) and violent behaviors.ResultsCannabis use frequency and severity were significant predictors of violent behaviors. After adjustment for time, age, sex, ethnicity, psychiatric diagnoses, impulsivity and use of alcohol and stimulants, odds ratios were of 1.91 (p <0.001) between each frequency profile, and 1.040 (p <0.001) for each increase of one point of the severity of cannabis use score (0 to 79).Image:ConclusionsThese findings have important implications for clinicians, demonstrating that cannabis use may have serious adverse consequences in a psychiatric population. Nevertheless, the mechanisms underlying this association remain unclear.Disclosure of InterestNone Declared

Association between adolescents who are victims of bullying and weapon possession

ObjectiveTo verify the association between victims of bullying and weapon possession among school adolescents. MethodsThis cross-sectional study was carried out with 2,296 high school students aged 14–19 years. An instrument containing questions from the validated Youth Risk Behavior Survey questionnaire and the National School Health Survey was used. To describe the profile of interviewees, absolute and relative frequencies were calculated, and the chi-square test was applied to verify the existence of associations. To test the association of bullying with weapon possession, Poisson logistic regression (univariate and multivariate) was used. The significance level used for all analyses was 5%. ResultsAmong adolescents interviewed, 23.1% reported being victims of bullying. Among victims of bullying, 37.6% (PR = 1.68; 95% CI = 1.30 – 2.17) reported having already carried some type of weapon (knife, revolver, or truncheon) in the last 30 days, while the reported firearm possession was 38% (PR = 1.67; 95% CI = 1.16 – 2.40) and 47.5% of these adolescents carried some type of weapon (knife, revolver or truncheon) in the school environment (PR = 2.10; 95% CI = 1.50 – 2.93). ConclusionsIt could be observed that adolescents who are victims of bullying are twice as likely of carrying some type of weapon (knife, revolver, or truncheon) to the school environment, and are also more likely of carrying a firearm.

Detailed study of HWP non-idealities and their impact on future measurements of CMB polarization anisotropies from space (Corrigendum)

We study the propagation of a specific class of instrumental systematics to the reconstruction of the B-mode power spectrum of the cosmic microwave background (CMB). We focus on the non-idealities of the half-wave plate (HWP), a polarization modulator that is to be deployed by future CMB experiments, such as the phase-A satellite mission LiteBIRD. We study the effects of non-ideal HWP properties, such as transmittance, phase shift, and cross-polarization. To this end, we developed a simple, yet stand-alone end-to-end simulation pipeline adapted to LiteBIRD. We analyzed the effects of a possible mismatch between the measured frequency profiles of HWP properties (used in the mapmaking stage of the pipeline) and the actual profiles (used in the sky-scanning step). We simulated single-frequency, CMB-only observations to emphasize the effects of non-idealities on the BB power spectrum. We also considered multi-frequency observations to account for the frequency dependence of HWP properties and the contribution of foreground emission. We quantified the systematic effects in terms of a bias $\Delta r$ on the tensor-to-scalar ratio, $r$, with respect to the ideal case without systematic effects. We derived the accuracy requirements on the measurements of HWP properties by requiring $\Delta r < 10^{-5}$ (1% of the expected LiteBIRD sensitivity on $r$). Our analysis is introduced by a detailed presentation of the mathematical formalism employed in this work, including the use of the Jones and Mueller matrix representations.

Exploring the lexical profile of advanced L2 writers: Longitudinal data from the Russian Overseas Flagship program

AbstractThis study explores the lexical profile of essays written by 48 advanced learners of second language (L2) Russian who participated in the Russian Overseas Flagship, an intensive year‐long study abroad program designed to help students reach Interagency Language Roundtable (ILR) Level 3 proficiency in all skills. Using the lexical frequency profile and P–Lex as measures of vocabulary sophistication, the study found that over the 9 months of the program, students significantly increased their usage of words from the lowest frequency bands. This adds to previous findings that knowledge of lexical items at the 3,000–5,000 word frequency levels predicts reading proficiency at the ACTFL advanced high–superior level in Russian. However, the increase of vocabulary sophistication was not clearly correlated with improvements in the students’ writing proficiency scores, as measured on the ILR scale. A qualitative analysis of the students’ low‐frequency vocabulary usage reveals their control of native Russian vocabulary and derivational morphology. The analyses reveal the effects of writing tasks on student vocabulary usage.