Actual Frequency Research Articles

Design and Analysis of Load Frequency Control for a Two-Area Power System Using Conventional PID and FPID Controllers

Power system stability is required to maintain a continuous balance between power generation and load demand. Frequency control is also a major function of automatic generation control and one of the most important control problems in power system design and operation. So, a robust control system must be implemented for controlling the actual power and frequency. This paper mainly focuses on the design of a two-area power system with a rated frequency of 50 Hz, which is used in Myanmar, using the fuzzy-PID method to control the load frequency. It also aims to imply from one area to another when demand suddenly increases or decreases. It involves applying mathematical formulas and models to analyze how an automatic generation control works. The plan is first implemented in a single area before being modified to a two-area power system with and without controllers. The output results are simulated with MATLAB/ SIMULINK.

Significance of the sample determination in assessment of radiological examinations frequencies for population doses due to medical exposures

The radiological examination frequency, i.e. the number of examinations performed annually, is necessary for estimating the collective effective dose of the population from medical exposures with ionizing radiation. Examination frequency surveys usually collect data from a limited number of radiological facilities participating in the survey. The collected data are then extrapolated to the existing radiological facilities in a country/region. Thus, the number of facilities and the specific facilities to participate, as well as, the extrapolation method used, are significant elements when designing the survey sample and methodology for examinations frequency assessments.This work attempted to simulate the situation when examination frequency data are collected from a limited number of facilities by investigating several “virtual sample” designs and two extrapolation methods. Comparisons between the calculated − by extrapolation – and the actual examination frequency in the country were made, for several scenarios and examination type data sets. The uncertainties were estimated and discussed thoroughly.The findings of this work highlighted the need for appropriate registry of the existing facilities in a country/region, the categorization of facilities considering the medical sector pattern in the country/region, the representativity and homogeneity of the samples used for a survey, as well as, the necessity for quality control of the collected examination frequency data.The results showed that when the aforementioned conditions were fulfilled, the examination frequency could be calculated with reasonable accuracy, based on data collected from a limited number of facilities.The paper also provides suggestions and tips for the collection and analysis of examination frequency data.

Determining anthropogenic pressure on the Southern Black Sea blue flag beaches

Coasts are settlement areas that attract human for many years. Türkiye, geographically located on Mediterranean Basin and Asian Continent passage with unique climate regime, has a great coastal zone. The mid-latitude geographic setting makes possible to experience coastal recreation and tourism activities for almost all year along. Among all activities sun, sea and sand tourism can be placed on the first stage. Recent changes in local climate of the Black Sea such as rising mean atmospheric temperatures and increasing number of sunny days have triggered touristic beach activities in the region. In the literature, there are different techniques for grading and classifying coastal beaches. In this study, as an integral part of coastal landscape formation Land Use/Land Cover (LULC) structure is linked to landscape value and regarded as cover changes that determines landscape pattern of the area under investigation. The research rationale of this study is based on an assumption of Southern Black Sea coastal blue flag beaches are under severe anthropogenic pressure. For this purpose, 15 blue flag beaches which are located on the Black Sea coast of Türkiye were selected based on their morphological dimensions. To determine landscape changes and potential human induced effects on selected beaches for the last 35–40 years period, georeferenced, atmospherically corrected Landsat 5 TM and Landsat 8 OLI-TIRS satellite images were used. Furthermore, carrying capacities for all researched beaches were calculated and documented in order to find the actual human usage frequencies during the high season. According to results of the study, it is clearly observed that all beach areas are under anthropogenic pressure. The most important evidence of this situation is the proportional increases in the IS (Impervious Surface) cover class in the classified images between 1984 and 1985 and 2021 in all 15 beaches. Moreover, these increases have reached up to 5–6 times for some beaches. As inferred, from the field surveys, beach carrying capacities were also exceeded for the most of the beaches under investigation. This means the blue flag beaches of Southern Black Sea are not only affected by construction and urbanization but also under intense pressure of overuse during the high seasons. It is revealed that these areas should be carefully managed with state-of-the-art techniques that prioritize adaptive planning that takes into account all stakeholders participation. Moreover, the activities, authorization and attitudes of municipalities regarding the coastal zones must be limited and inspected by a higher organization.

Multiscale stochastic optimal control of hysteretic structures based on wavelet transform and probability density evolution method

PurposeContemporary stochastic optimal control by synergy of the probability density evolution method (PDEM) and conventional optimal controller exhibits less capability to guarantee economical energy consumption versus control efficacy when non-stationary stochastic excitations drive hysteretic structures. In this regard, a novel multiscale stochastic optimal controller is invented based on the wavelet transform and the PDEM.Design/methodology/approachFor a representative point, a conventional control law is decomposed into sub-control laws by deploying the multiresolution analysis. Then, the sub-control laws are classified into two generic control laws using resonant and non-resonant bands. Both frequency bands are established by employing actual natural frequency(ies) of structure, making computed efforts depend on actual structural properties and time-frequency effect of non-stationary stochastic excitations. Gain matrices in both bands are then acquired by a probabilistic criterion pertaining to system second-order statistics assessment. A multi-degree-of-freedom hysteretic structure driven by non-stationary and non-Gaussian stochastic ground accelerations is numerically studied, in which three distortion scenarios describing uncertainties in structural properties are considered.FindingsTime-frequency-dependent gain matrices sophisticatedly address non-stationary stochastic excitations, providing efficient ways to independently suppress vibrations between resonant and non-resonant bands. Wavelet level, natural frequency(ies), and ratio of control forces in both bands influence the scheme’s outcomes. Presented approach outperforms existing approach in ensuring trade-off under uncertainty and randomness in system and excitations.Originality/valuePresented control law generates control efforts relying upon resonant and non-resonant bands, and deploys actual structural properties. Cost-function weights and probabilistic criterion are promisingly developed, achieving cost-effectiveness of energy demand versus controlled structural performance.

Construction and Verification of Urinary Tract Infection Prediction Model for Hospitalized Rehabilitation Patients with Spinal Cord Injury

ObjectiveTo explore the influencing factors of urinary tract infection in hospitalized patients with spinal cord injury, and to construct and verify the nomogram prediction model. MethodsThis study is a retrospective cohort study. From January 2017 to March 2022, 558 patients with spinal cord injury admitted to the Department of Rehabilitation Medicine of a tertiary hospital in Anhui Province, China were selected as the research objects, and they were randomly divided into training group (n=390) and verification group (n=168) according to the ratio of 7: 3, and clinical data including socio-demographic characteristics, disease-related data and laboratory examination data were collected. Univariate analysis and multivariate Logistic regression were used to analyze the influencing factors of urinary tract infection in hospitalized patients with spinal cord injury. Based on this, a nomogram prediction model was constructed with the use of R software, and the risk prediction efficiency of the nomogram model was verified by the receiver operating characteristic(ROC) curve and calibration curve. ResultsLogistic regression analysis showed that ASIA-E grade (compared with ASIA-A grade) was an independent protective factor for urinary tract infection in hospitalized patients with spinal cord injury (OR<1, P<0.05), while white blood cell count and indwelling catheter were independent risk factors for urinary tract infection in hospitalized patients with spinal cord injury (OR>1, P<0.05). Based on this, a nomogram risk predictive model for predicting urinary tract infection in hospitalized rehabilitation patients with spinal cord injury was constructed, which was proved to have good predictive efficiency. In the training group and the verification group, the area under the ROC curve(AUC) of the nomogram model is 0.808 and 0.767, and the 95%CI of the AUC of the nomogram in the training group and the verification group is 0.760∼0.856 and 0.688∼0.845, indicating the nomogram model has good discrimination. According to the calibration curve, the prediction probability of the nomogram model and the actual frequency of urinary tract infection in the training group and the verification group are in good consistency, and the results of the Hosmer-Lemeshow bias test also suggest that the nomogram model has good calibration degree in both the training group and the verification group (P=0.329, 0.067). ConclusionASIA classification level, white blood cell count and indwelling catheter are independent influencing factors of urinary tract infection in hospitalized patients with spinal cord injury. The nomogram prediction model based on the above factors can simply and effectively predict the risk of urinary tract infection in hospitalized patients with spinal cord injury, which is helpful for clinical medical staff to identify high-risk groups early and implement prevention, treatment and nursing strategies in time.

Vibration Response of Metal Plate and Shell Structure under Multi-Source Excitation with Welding and Bolt Connection

There are many excitation sources and complex vibration environments in combine harvesters. The coupling and superposition of different vibration signals on the plate and shell seriously affect the working parts of the body. This also reduces the reliability of the whole machine. At present, domestic and foreign research on existing harvesters mainly focuses on harvesting performance, with less research on vibration characteristics. Therefore, in this paper, the vibration response of the metal plate–shell under the two connection modes of bolt connection and welding is studied, in order to optimize the design and structure of the plate–shell structure of the combine harvester and improve the overall performance. First, the welded and bolted plates are numerically modeled using Hypermesh pre-processing functions. Then, the boundary conditions are simulated by continuous variable stiffness elastic constraint experiments. Finally, the intrinsic vibration dynamic model of the four-sided simply supported plate and four-sided solidly supported plate is established using the modal superposition method. By analyzing the modal frequencies and vibration patterns, the following results are obtained. The connection method between the plate and the frame has a significant impact on the inherent vibration characteristics of the plate. The bolt connection will make the plate’s intrinsic vibration frequency higher than that of the welding method, but the effect on the plate’s intrinsic vibration pattern is more minor. At the same time, in order to verify the accuracy of the model, the actual modal vibration patterns and frequencies of the same proportion of plates in the modal test are compared with the results of modal vibration patterns and frequencies obtained by Ansys. The errors of the two dynamic model analytical methods are within 1% and 3%, respectively. This result verifies the accuracy of the dynamic model of the metal plate and shell structure under different connection methods.

A haemopneumothorax revealing thoracic endometriosis

Thoracic endometriosis is a rare disease but its actual frequency may be underestimated. Optimal management remains controversial. A multidisciplinary management approach, including surgery and hormone therapy, seems to give the best results and reduces recurrence. We report a case of a patient presenting with recurrent haemopneumothorax caused by thoracic endometriosis and treated surgically by video thoracoscopy and hormonal treatment.

Enhancing rational approximation of wideband resonant MIMO systems with frequency-domain data

Vector Fitting (VF) is a successful methodology for both time and frequency domain estimation of dynamic systems. These algorithms have gained popularity as a system identification tool due to their ability to provide a practical procedure for accurately approximating the measured frequency response behavior of complex and highly resonant dynamic systems using rational models. Instrumental Variable (IV) techniques can also be added to the VF algorithm to enhance the optimality of the solutions in the presence of measurement noise. In this context, this paper presents a multiple-input multiple-output (MIMO) generalization of instrumental variable (IV-)VF. The proposed algorithm can be applied to accurately estimating models formed by either continuous- or discrete-time rational basis functions (RBFs). We show that such a generalization preserves the main implementation features observed in Standard VF, but with improved optimality property for its solutions. Additionally, in order to alleviate convergence problems that may arise from the fixed high-frequency normalization, we also present in this paper how to incorporate in the proposed IV-VF method the relaxed formulation found in standard VF for both the continuous and discrete-time cases. The resulting MIMO IV-VF algorithm can be easily understood by VF users, and its applicability is discussed by using an estimation case study with two power system pieces of equipment (an 88 kV Transformer and a 550 kV Instrument Transformer) for which actual frequency domain measurements were collected in the field. It is shown that the proposed algorithm significantly improves the modeling accuracy when compared to standard VF algorithms.

Can the phase of SNR oscillations in GNSS-IR be used to estimate sea-level height?

In existing global navigation satellite system-interference reflectometry (GNSS-IR) research, only the frequency of signal-to-noise ratio (SNR) oscillations has been used to estimate sea-level height. However, the characteristic parameters of SNR oscillations are not isolated from each other, and a single feature cannot accurately and comprehensively capture the environmental changes of reflecting surface. Our simulation results show that for the nonlinear least squares (NLS), when there is a certain difference between the fitting frequency and the actual frequency of SNR oscillations, the deviation of the phase solution obtained is approximately linear with the frequency difference. Consequently, a linear phase correction GNSS-IR sea-level estimation method is constructed in this study. This method integrates the Lomb–Scargle periodogram (LSP) and NLS to process SNR oscillations, using the phase obtained from NLS to correct the retrieval error of LSP. Through processing SNR data from four sites for nearly half a year, we verified the stability of the relationship between phase and frequency-based retrieval error at different sites in continuous monitoring, and established the relationship model between the two. Then, utilizing the relationship model acquired at different sites, we estimated the sea-level variations for the next 6 months at each site through joint frequency and phase versus reflector height relationships. Experimental results show that the phases acquired from NLS can effectively correct the retrieval error of LSP. Compared with the traditional method using only frequency, the root mean square error and mean absolute error of the retrieval results obtained from the linear phase correction GNSS-IR sea-level estimation method based on LSP-NLS are both reduced by about 60%. This multi-feature fusion technique introduces a new perspective and technical approach for GNSS-IR sea-level estimations.

Weight extracting transform for instantaneous frequency estimation and signal reconstruction

This paper introduces a novel time–frequency analysis method called the Weight Extracting Transform (WET). The primary objective of WET is to enhance the energy concentration in linear time–frequency representations for time-varying signals. By aggregating the time–frequency blur produced by the short-time Fourier transform onto the actual instantaneous frequency, WET improves the readability and accuracy of the time–frequency representation. Additionally, the algorithm is extended to a more general linear time–frequency transform known as the chirplet transform, which effectively handles fast-varying signals. The WET method excels at distinguishing components with closely spaced instantaneous frequencies and can reconstruct the original signal from its time–frequency representation. Experimental results using simulated and real-world signals demonstrate that WET achieves superior energy concentration and noise robustness compared to existing methods.

The impacts of perceived access to public open spaces on non-physical wellbeing: focused on international graduate students in Seoul

ABSTRACT The growing trend of international student mobility in Asia and the associated challenges, advocating for the use of public open spaces to enhance students’ wellbeing. Using a case study of Seoul, South Korea, this research offers an investigation into the interplay between access to these spaces and the non-physical wellbeing of international graduate students. It primarily contrasts perceived access and the actual frequency of visits to these spaces. Variables derived from literature were compiled into a questionnaire in which then was analyzed with both descriptive and inferential statistics. The study underscores the pivotal role of perceived access to public open spaces both in the city context and campus context, in enhancing the non-physical, highlighting the need for urban planning to prioritize quality access and awareness over mere frequency of visits. This study also emphasizes on the importance of perceived scale, safety, beauty, and ambiance attributes in moderating the positive impact of access to public open spaces. This result emphasizes on spaces that are not only physically accessible but also psychologically inviting and culturally resonant. This finding challenges the traditional focus on the quantitative expansion and underscoring the importance of perceived access for creating inclusive urban environments for an educational hub.

A Systematic Review and Case Illustrations of Misdiagnosing Intracranial Aneurysms.

Modern neuroimaging methods do not completely rule out false diagnoses of intracranial aneurysms which can lead to an unwarranted operation associated with risks of complications.However,surgical interventions for falsely diagnosed aneurysms are quite rare. The purpose of this study is to demonstrate two clinical cases of false-positive aneurysms and a systematic review of the literature dedicated to the incidence and etiology of false-positive aneurysms, identifying risk factors associated with false-positive aneurysms. A literature search in two databases (PubMed and Web of Science) using keywords "mimicking an intracranial aneurysm", "presenting as an intracranial aneurysm", "false positive intracranial aneurysms", and "neurosurgery" was conducted. A total of 243 papers were found in the initial search in two databases. Sixteen papers (including 20 patients) were included in the final analysis. There were 10 women and 10 men. The most common location of false-positive aneurysms was the bifurcation of the middle cerebral artery (MCA). In the posterior circulation, false-positive aneurysms were identified either on the basilar artery, or at the vertebro-basilar junction. The main causes of false intracranial aneurysm diagnosis included artery occlusion with vascular stump formation, infundibular widening, fenestration, arterial dissection, contrast extravasation, and venous varix.In conclusion, summarizing the results of our analysis, we can say that surgical interventions for false-positive aneurysms are an underestimated problem in vascular neurosurgery. Despite extremely rare published clinical observations, the actual frequency of erroneous surgical interventions for false-positive aneurysms is unknown.

Identifying the Actual Operating Frequency of the Microwave Sensor With High Resolution and High Dynamic Range

Identifying the Actual Operating Frequency of the Microwave Sensor With High Resolution and High Dynamic Range

Research on Improvement Methods for Driven System of Bio-Inspired Aircraft to Increase Flight Speed

The flapping-wing ornithopter is an aircraft that imitates the flight of birds in nature. It has significant potential and value in various fields such as surveying, search and rescue, military reconnaissance, and unmanned warfare, due to its biomimetic stealth and high efficiency in low Reynolds number flight. However, the cruising speed of current flapping-wing ornithopters is generally lower than that of birds of the same size, which seriously affects biomimicry, mission capability, and wind resistance. Increasing the cruising speed can make the aircraft fly more like a bird, improve the efficiency of reconnaissance missions and wind resistance per unit time, and has important research significance. However, the methods to increase the cruising speed of flapping-wing ornithopters are currently lacking. Firstly, this paper presents improvements to the propulsion system based on the team’s “Dove” aircraft to meet the speed requirements. The actual flapping frequency and rocking arm end torque of the “Dove” aircraft under different voltages are tested. To select and match the motor and gearbox in the propulsion system, a method for matching and selection among the motor, gearbox, and load is proposed. Finally, wind tunnel experiments and flight validations are conducted on the improved flight prototype. The wind tunnel experiments show that the increase in flapping frequency has a significant impact on thrust. The trimmed states at different speeds are obtained. The flight validation demonstrates the sustained high-speed flight capability of the aircraft. At a flapping frequency of approximately 15 Hz, the average flight speed of the aircraft is 13.3 m/s within a 15 min duration, which is close to the actual flight speed of pigeons. The duration of high-speed flight is tripled compared to the initial duration. The speed improvement successfully enhances the biomimicry and efficiency of reconnaissance missions per unit time for the aircraft.

Seeking for associations of I/D polymorphism of ACE gene with self-reported work performance, memory, and cardiovascular health in a professional leadership community

Introduction. Maintaining labor efficiency, working under conditions of stress and uncertainty, high level of requirements to the functional state of workers in various professions actualize the occupational health study of work performance. Methodological applications of predictive medicine and psychogenetics make it possible to identify specific hereditary (biological) predispositions of individuals, to carry out professional orientation of a person, to provide humanistic recommendations on occupation of a certain type of professional activity.&#x0D; The study aims to identify a correlation between ACE genotypes and work performance capability in individuals from a professional leadership community.&#x0D; Materials and methods. Individuals from a professional leadership community, after dividing into two cohorts consisting of entrepreneurs and non-entrepreneurs, were interviewed and genotyped for evidence of genotype-by-insertion/deletion (I/D) polymorphism associations of the angiotensin I converting enzyme (ACE) gene and health status. Answers to 4 questions characterized the state of work performance and memory, and another 4 questions characterized the cardiovascular system. The mean age was 37±1.7 years for entrepreneurs and 34.23±0.66 years for non-entrepreneurs. There were 44 females and 129 males among them.&#x0D; Results. Analysis of genotyping of 173 people (25 entrepreneurs and 148 non-entrepreneurs) revealed a significant deviation of actual frequencies of I and D alleles from theoretically expected values in the whole group of managers and between non-entrepreneurs (p=0.95, χ2&gt;3.8). In all groups, there was a marked increase in the frequency of the I/I genotype at the expense of a decrease in the frequency of the D/D genotype compared to the literature data. A significant difference between D/D and I/D genotypes in work performance was found in entrepreneurs (p=0.9817), which coincides with a significant difference between their representatives by age (p&gt;0.99). Contrary to expectations, representatives of the D/D genotype, at least entrepreneurs, demonstrated the most optimal level of functioning of the autonomic nervous system. No associations were found between the genotype for the ACE gene (rs4646994) and work performance and memory.&#x0D; Conclusion. In the total sample of leaders and among the subgroup of non-entrepreneurs, a strong and reliable change in the frequencies of alleles I and D was found compared to the theoretically expected (frequencies). There was a significant increase in the frequency of I/I genotype in all groups. The significant difference in the rates between the D/D and I/D groups coincides with a significant difference between their representatives in terms of age. According to the results of test answers, representatives of entrepreneurs of D/D genotype had the most optimal level of vegetative nervous system functioning.

Collaborative Vehicle-to-Grid Operations in Frequency Regulation Markets

Problem definition: We study the operations of electric vehicles (EVs) providing frequency regulation services to the electric grid in vehicle-to-grid (V2G) systems. In particular, individually owned EVs collaboratively bid in the regulation market, coordinated by a platform that operates the network of charging equipment. We study how the platform determines optimal pricing incentives for drivers to plug in their EVs, accounting for heterogeneous driving schedules. Methodology/results: We model the platform’s pricing optimization problem as a bilevel program: At the upper level, the platform determines hourly rebates for EV owners to plug in their EVs and capacity bids in the regulation market; at the lower level, individual travelers optimize their travel and charging schedules in response to pricing incentives. To account for uncertainties and heterogeneity in regulation market prices and travel patterns, we adopt distributionally robust optimization techniques to formulate the problem as a mixed-integer second-order cone program. We conduct a computational study based on the California Household Travel Survey data set and actual frequency regulation prices. Our results show that the ability to offer time-varying rebates and install workplace chargers can significantly improve the V2G platform’s expected profits. Managerial implications: As EV adoption progresses past the nascent stage, V2G business models become more viable. Successful implementation of V2G provides economic incentive for switching to EVs, potentially helps sustain adoption growth, and complements the growth of renewable power by helping stabilize the grid. Our findings shed light on the design of driver incentives for V2G systems. Funding: R. Tang acknowledges support from the National Natural Science Foundation of China [Grant 72201206]. Supplemental Material: The online appendices are available at https://doi.org/10.1287/msom.2022.0133 .

Dynamic modeling and analysis of rolling bearing faults under time-varying excitations considering defect deformation

Fault mechanism analysis is one of the methods in fault diagnosis, and the dynamic modeling of rolling bearing faults plays a crucial role in studying fault mechanisms. Existing dynamic fault models only consider the impact of fault size and bearing speed on the impact force, providing an incomplete description of the impact force. In order to more accurately describe the dynamic fault model of impact forces, this paper focuses on the deep groove ball bearing with outer race faults. Factors such as defect deformation, speed, and fault size are considered, and an instantaneous impact force excitation function is proposed. Based on this proposed excitation function, a dynamic model for the outer race fault of deep groove ball bearings is established. Finally, through simulation and experimental comparison, the results indicate that the fault characteristic frequencies and their harmonics of the model in this paper are closer to the actual fault characteristic frequencies, reducing the error by 1 to 2 Hz. Therefore, the model proposed in this paper is more effective and accurate, providing a more precise rolling bearing fault model for the study of fault mechanisms.

Concept for Parameter Design and Optimization of Surface Acoustic Wave Devices

Concept for Parameter Design and Optimization of Surface Acoustic Wave Devices

Анализ возможностей оптимизации выбора ультразвукового оборудования для нанесения функциональных покрытий

To meet the requirements affecting the quality of functional coatings, various technologies are currently being used, one of which is the use of ultrasonics. To form functional coatings, ultrasonics are used both at the stage of surface preparation and at the stage of coating deposition. Thus, at the stage of surface preparation, ultrasonics allow making surface preclean, ensuring the necessary surface roughness due to ultrasonic rolling, as well as preactivation of the surface before nitriding due to surface plastic deformation. In case of coating deposition, ultrasonics contribute to better nitriding and painting. However, ultrasonic equipment used in various preparation and coating deposition processes differs significantly in its characteristics. Thus, the ultrasonic generators vary in alternator capacity, specific material consumption, actual frequency, as well as design features that ensure stable operation, for example, automatic frequency control. The converters differ from each other in accomplishable amplitudes, power and actual frequency. In this regard, the aim of the work is to develop recommendations on the use of ultrasonic equipment in various technical processes for the creation of functional coatings. The paper studies ultrasonic equipment used in surface preparation and functional coating application process. The main process-dependent parameters aimed at choosing the required equipment have been characterized. Recommendations are given on the use of ultrasonic equipment for various functional coatings generation, when a converter-generator couple is found and it meets the requirements for most surface preparation and coating deposition processes.

Comparing the efficacy of anti-seizure medications using matched cohorts on a large insurance claims database

Epilepsy is a severe chronic neurological disease affecting 60 million people worldwide. Primary treatment is with anti-seizure medicines (ASMs), but many patients continue to experience seizures. We used retrospective insurance claims data on 280,587 patients with uncontrolled epilepsy (UE), defined as status epilepticus, need for a rescue medicine, or admission or emergency visit for an epilepsy code. We conducted a computational risk ratio analysis between pairs of ASMs using a causal inference method, in order to match 1034 clinical factors and simulate randomization. Data was extracted from the MarketScan insurance claims Research Database records from 2011 to 2015.The cohort consisted of individuals over 18 years old with a diagnosis of epilepsy who took one of eight ASMs and had more than a year of history prior to the filling of the drug prescription. Seven ASM exposures were analyzed: topiramate, phenytoin, levetiracetam, gabapentin, lamotrigine, valproate, and carbamazepine or oxcarbazepine (treated as the same exposure).We calculated the risk ratio of UE between pairs of ASM after controlling for bias with inverse propensity weighting applied to 1034 factors, such as demographics, confounding illnesses, non-epileptic conditions treated by ASMs, etc. All ASMs exhibited a significant reduction in the prevalence of UE, but three drugs showed pair-wise differences compared to other ASMs. Topiramate consistently was associated with a lower risk of UE, with a mean risk ratio range of 0.68–0.93 (average 0.82, CI: 0.56–1.08). Phenytoin and levetiracetam were consistently associated with a higher risk of UE with mean risk ratio ranges of 1.11 to 1.47 (average 1.13, CI 0.98–1.65) and 1.15 to 1.43 (average 1.2, CI 0.72–1.69), respectively.Large-scale retrospective insurance claims data - combined with causal inference analysis - provides an opportunity to compare the effect of treatments in real-world data in populations 1,000-fold larger than those in typical randomized trials. Our causal analysis identified the clinically unexpected finding of topiramate as being associated with a lower risk of UE; and phenytoin and levetiracetam as associated with a higher risk of UE (compared to other studied drugs, not to baseline). However, we note that our data set for this study only used insurance claims events, which does not comprise actual seizure frequencies, nor a clear picture of side effects. Our results do not advocate for any change in practice but demonstrate that conclusions from large databases may differ from and supplement those of randomized trials and clinical practice and therefore may guide further investigation.