729 research outputs found
Red neuronal profunda optimizada para la clasificación de psoriasis de alta precisión a partir de imágenes dermatoscópicas
Accurate classification of psoriasis is critical in dermatological diagnostics due to the disease’s diverse clinical presentations and varying severity levels. With numerous subtypes and their visual similarities to other dermatological conditions, precise diagnosis typically requires expert medical knowledge. Early and accurate identification of psoriasis subtypes is essential for initiating timely treatment. This study introduces a novel hybrid deep learning architecture that integrates EfficientNet with Long Short-Term Memory (LSTM) networks for the automated classification of psoriasis from dermoscopic images. The proposed model is designed to simultaneously capture spatial features through EfficientNet and temporal or sequential patterns via LSTM units, thereby improving classification performance. The models are trained and tested on a publicly benchmark dataset comprising 7 distinct classes using the publically available benchmark dataset by Dermnet and BFL-NTU. Experimental results demonstrate that the proposed architecture significantly outperforms the baseline models such as VGG16 and ResNet50, with superior accuracy 89.7% and robust performance across metrics like recall, F1-score with 88%, and Region of Convergence (ROC) of 97%. This compact design with low trainable parameters reduces the computational time and memory makes the model well-suited for deployment for portable devices and enabling real-time mobile-based dermatological assessments.La clasificación precisa de la psoriasis es crucial en el diagnóstico dermatológico debido a las diversas presentaciones clínicas de la enfermedad y sus distintos niveles de gravedad. Con numerosos subtipos y sus similitudes visuales con otras afecciones dermatológicas, un diagnóstico preciso generalmente requiere conocimientos médicos especializados. La identificación temprana y precisa de los subtipos de psoriasis es esencial para iniciar un tratamiento oportuno. Este estudio presenta una novedosa arquitectura híbrida de aprendizaje profundo que integra EfficientNet con redes de memoria a largo plazo (LSTM) para la clasificación automatizada de la psoriasis a partir de imágenes dermatoscópicas. El modelo propuesto está diseñado para capturar simultáneamente características espaciales mediante EfficientNet y patrones temporales o secuenciales mediante unidades LSTM, mejorando así el rendimiento de la clasificación. Los modelos se entrenan y prueban en un conjunto de datos de referencia público que comprende siete clases distintas, utilizando el conjunto de datos de referencia disponible públicamente de Dermnet y BFL-NTU. Los resultados experimentales demuestran que la arquitectura propuesta supera significativamente a los modelos de referencia, como VGG16 y ResNet50, con una precisión superior del 89,7% y un rendimiento robusto en métricas como la recuperación, la puntuación F1 del 88% y la región de convergencia (ROC) del 97%. Este diseño compacto, con bajos parámetros de entrenamiento, reduce el tiempo de cálculo y la memoria, lo que lo hace ideal para su implementación en dispositivos portátiles y permite evaluaciones dermatológicas móviles en tiempo real
Scheduling in wireless cellular data networks
This thesis studies the performance of scheduling policies in a wireless cellular data network. We consider a cell within the network. The cell has a single base station serving a given number of users in the cell. Time is slotted and the base station can serve at most one user in a given time slot. The users are mobile and therefore the data transfer rate available to each user changes from time slot to time slot depending on the distance from the base station and the terrain of the user. There are two conflicting objectives for the base station: maximize the data throughput per time slot, and maintaining fairness'. To maximize the data throughput, the base station would like to serve the user with the highest available data rate, but this can lead to starvation of some users. To ensure fairness, no user should be unserved for a long' time, i.e., users should be served in a round-robin manner. Although this problem has been studied in the literature to some extent, existing methods to do this are ad-hoc. Our goal is to derive policies that have a sound theoretical basis, and at the same time are computationally tractable, are easy to implement, are fair to all the users and beneficial for the service providers. We formulate the problem of finding an optimal scheduling policy as a Markov Decision Process (MDP) and prove some characteristics of the optimal policy. Since solving the MDP to optimality is infeasible, given the huge size of the problem, we develop heuristic policies called index policies'. These policies are based on a closed form index' for every user that depends only its own current state. We derive this index using a policy improvement approach based on Markov Decision Processes. We also compare their performance with existing policies through simulation. We develop such index policies in two settings: when every user always has ample data waiting for it to be served (the infinitely backlogged case), and when data arrives for every user in every time slot according to some distribution (the external data arrival case). Further, we consider the case of users entering and leaving the cell as well, but only from a simulation perspective
Anatomic intra-articular reconstruction of the cranial cruciate ligament in dogs: The femoral tunnel
Zielstellung: Die Ruptur des vorderen Kreuzbandes (VkB) ist die häufigste Ursache einer Lahmheit beim Hund. Im Gegensatz zu der Humanmedizin, wo die anatomische intraartikuläre Rekonstruktion des vorderen Kreuzbandes als Therapie der Wahl gilt, wird die intraartikuläre Rekonstruktion beim Hund nur selten durchgeführt und hat bis jetzt nicht dauerhaften Erfolg. Die anatomische Platzierung der Bohrkanäle ist bei Menschen für den Erfolg der Operation bei Menschen entscheidend. Erstes Ziel der Studie war die Bestimmung der radiologischen Lage des Zentrums des femoralen vorderen Kreuzbandursprungs beim Hund. Zweites Ziel war die Entwicklung und Erprobung eines Zielgerätes für die arthroskopisch-assistierte, anatomische vordere Kreuzbandrekonstruktion beim Hund.
Material und Methode: A. Radiologische Studie: Die kraniale Begrenzung des femoralen Ursprungs des vorderen Kreuzbandes (VK) wurde mit einem röntgendichten Draht bei 49 Femora orthopädisch gesunder Hunde (KM > 20 kg) markiert. Anschließend wurde eine Computertomographie und 3D- Rekonstruktion jedes Femurs angerfertigt, anhand derer der Ursprung manuell segmentiert und das Zentrum berechnet wurde. Schließlich wurden, basierend auf den 3D-Modellen, virtuelle Röntgenbilder in zwei Ebenen berechnet. An diesen wurde die Position des berechneten Zentrums mit drei unterschiedlichen Methoden bestimmt (4x4-Gitterbox-Methode und prozentuale Position für die medio-laterale Projektion; Ziffernblattmethode für die disto-proximale Projektion). B. Zielgerät: Hintergliedmaßen (n = 12) von 6 Hundekadavern (KM ≥20 kg) wurden verwendet. Eine Gliedmaße jedes Kadavers wurde zufällig ausgewählt und die kaudo-kraniale Lage des Zentrums des vorderen Kreuzbandansatzes (vKBA) in medio-lateralen Röntgenbildern berechnet und anschließend auf ein justierbares Zielgerät übertragen. Unter arthroskopischer Kontrolle wurde das Zielgerät hinter der lateralen Kondyle eingehakt und ein Steinmann Pin von extra nach intraartikulär platziert. Die Position der resultierenden Bohrkanäle wurde sowohl röntgenologisch bestimmt als auch dreidimensional mit dem anatomischen Zentrum des vKBA der kontralateralen Hintergliedmaßen verglichen.
Ergebnisse: A. Radiologische Studie: In der medio-lateralen Projektion befand sich das Zentrum des femoralen Kreuzbandursprungs im zweiten Rechteck von proximal in der kaudalen Spalte. Die mittlere prozentuale kaudo-kraniale und proximo-distale Position war 20,2 % (± 2,2), beziehungsweise 33,8% (± 3,7). Im disto-proximalen Röntgenbild lag in 97,6 % der Femora das Zentrum des femoralen Kreuzbandursprungs zwischen 14:00 und 15:00 Uhr. B. Zielgerät: In allen postoperativen Röntgenaufnahmen lagen die sechs Bohrkanäle im bzw. nahe dem Zentrum des vKBA. Die 3D- Messungen ergaben eine mediane Abweichung der Bohrkanalposition im Vergleich zum anatomischen Zentrum der kontralateralen Seite von 0,6 mm (Bereich:0,2– 0,9 mm).
Schlussfolgerung: Die erarbeiteten Referenzwerte können für die Planung sowie die intra- und postoperative Kontrolle der femoralen Bohrung verwendet werden. Die Verwendung eines justierbaren Zielgerätes ermöglicht die präzise anatomische Platzierung des femoralen Bohrkanals für die intraartikuläre Rekonstruktion des vorderen Kreuzbandes. Die beschriebene Methode wird helfen, eine Fehlplatzierung des femoralen Bohrkanals im Zuge der intraartikulären vorderen Kreuzbandplastik zu reduzieren. In Kombination mit dem bereits beschriebenen tibialen Zielgerät sind nun die technischen Voraussetzungen für die arthroskopisch-assistierte anatomische vordere Kreuzbandplastik in der Tiermedizin gegeben.Objective: Cranial cruciate ligament (CrCL) pathology is the most frequent cause of lameness in dogs. In contrast to human medicine, where anatomic reconstruction of the ACL is considered the treatment of choice, intra-articular repair in dogs is not commonly performed and until now has not met with enduring success. Accurate tunnel placement has been shown to be crucial in obtaining a successful outcome after anterior cruciate ligament reconstruction in humans. The first aim of our study was to define the radiographic location of the center of the femoral attachment of the CrCL in dogs, for the pre- operative planning as well as post-operative control of anatomical placement of the femoral tunnel. Second aim of the study was to develop and validate an aiming device for arthroscopic femoral tunnel placement.
Materials and Methods: A. Radiographic study: Using femora from 49 adult, orthopedically sound dogs (BW ≥ 20 kg), a radiopaque marker was placed on the cranial border of the femoral footprint of the CrCL. Computed tomography and 3D reconstruction of each femur was performed subsequently, followed by manual segmentation of the footprint on the 3D models and calculation of its center. Finally, virtual digital radiographs in two planes were produced and the location of the calculated center of the CrCL was expressed using three different methods (4x4 box grid method and percentage position for the medio-lateral projection; o’clock position for the disto-proximal projection). B. Aiming device: Hindlimbs (n=12) of 6 cadaveric dogs weighing ≥20 kg were used. One hindlimb from each cadaver was randomly chosen and the caudo- cranial position of the CrCL center was calculated, on standard medio-lateral stifle radiographs, and transferred onto to an adjustable aiming device. During stifle arthroscopy the aiming device was inserted and guide pin placed from extra-to-intra-articular. The position of the resulting bone tunnel was evaluated on stifle radiographs and also compared with the anatomic center of each contralateral hindlimb, in the three dimensional (3D) space.
Results: A. Radiographic study: In the medio-lateral radiographs the center of the femoral footprint was consistently located in the second rectangle from the top of the most caudal column of the 4x4 grid. The mean percentage caudo- cranial and proximo-distal location was 20.2% (± 2.2) and 33.8% (± 3.7), respectively. In the disto-proximal radiograph, the o’clock position of the CrCL center was between 2 and 3 o’clock in 97.6% of the femora. B. Aiming device: According to the postoperative radiographs, the location of all 6 intra-articular tunnel openings was consistent with the results of the radiographic study. In 3D space, arthroscopic femoral drilling resulted in a median deviation of the drill tunnels of 0.6 mm around the CrCL center. All tunnel openings were located within the CrCL insertion.
Conclusions: The reported data can be used to plan and verify the placement of the femoral tunnel opening during intra-articular anatomic CrCL repair. The use of the aiming device suggests that arthroscopic femoral tunnel placement can be achieved with high precision. The measurement for the device can be derived from a standard medio-lateral radiograph of the stifle, which is part of the diagnostic work up of every dog with lameness localized in the stifle. The proposed technique may reduce femoral tunnel misplacement when performing intra-articular CrCL repair in dogs. In combination with the described technique for arthroscopic tibial tunnel drilling, arthroscopic assisted anatomic reconstruction of the CrCL in dogs can be achieved
Only behavioral but not self-report measures of speech perception correlate with cognitive abilities
Good speech perception and communication skills in everyday life are crucial for participation and well-being, and are therefore an overarching aim of auditory rehabilitation. Both behavioral and self-report measures can be used to assess these skills. However, correlations between behavioral and self-report speech perception measures are often low. One possible explanation is that there is a mismatch between the specific situations used in the assessment of these skills in each method, and a more careful matching across situations might improve consistency of results. The role that cognition plays in specific speech situations may also be important for understanding communication, as speech perception tests vary in their cognitive demands. In this study, the role of executive function, working memory (WM) and attention in behavioral and self-report measures of speech perception was investigated. Thirty existing hearing aid users with mild-to-moderate hearing loss aged between 50 and 74 years completed a behavioral test battery with speech perception tests ranging from phoneme discrimination in modulated noise (easy) to words in multi-talker babble (medium) and keyword perception in a carrier sentence against a distractor voice (difficult). In addition, a self-report measure of aided communication, residual disability from the Glasgow Hearing Aid Benefit Profile, was obtained. Correlations between speech perception tests and self-report measures were higher when specific speech situations across both were matched. Cognition correlated with behavioral speech perception test results but not with self-report. Only the most difficult speech perception test, keyword perception in a carrier sentence with a competing distractor voice, engaged executive functions in addition to WM. In conclusion, any relationship between behavioral and self-report speech perception is not mediated by a shared correlation with cognition
Effects of noise exposure on young adults with normal audiograms II: Behavioral measures
An estimate of lifetime noise exposure was used as the primary predictor of performance on a range of behavioral tasks: frequency and intensity difference limens, amplitude modulation detection, interaural phase discrimination, the digit triplet speech test, the co-ordinate response speech measure, an auditory localization task, a musical consonance task and a subjective report of hearing ability. One hundred and thirty-eight participants (81 females) aged 18–36 years were tested, with a wide range of self-reported noise exposure. All had normal pure-tone audiograms up to 8 kHz. It was predicted that increased lifetime noise exposure, which we assume to be concordant with noise-induced cochlear synaptopathy, would elevate behavioral thresholds, in particular for stimuli with high levels in a high spectral region. However, the results showed little effect of noise exposure on performance. There were a number of weak relations with noise exposure across the test battery, although many of these were in the opposite direction to the predictions, and none were statistically significant after correction for multiple comparisons. There were also no strong correlations between electrophysiological measures of synaptopathy published previously and the behavioral measures reported here. Consistent with our previous electrophysiological results, the present results provide no evidence that noise exposure is related to significant perceptual deficits in young listeners with normal audiometric hearing. It is possible that the effects of noise-induced cochlear synaptopathy are only measurable in humans with extreme noise exposures, and that these effects always co-occur with a loss of audiometric sensitivity
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Virtual Reality in Orthopedic Surgery Training.
One emerging technology with the potential to improve and further transform the field of orthopaedic surgery is virtual reality (VR). VR has been explored and used in many different specialties with clinical applications, such as psychiatric therapy, pain management, rehabilitation, and traumatic brain injury. Recent studies have suggested that the use of VR during the training of orthopaedic surgery residents produces similar or improved surgical performance by residents. This is an area where VR can provide a tremendous benefit to the field of orthopaedic surgery, as it offers a safe and accessible complement to orthopaedic surgical training outside of the operating room (OR) and without involving patients directly. This review will elucidate the current state of virtual reality use in the training of orthopaedic surgeons and highlight key benefits and challenges in its application as a training resource
Timing of treatment in osteosarcoma: challenges and perspectives - a scoping review.
BACKGROUND: The timing of events in the management of osteosarcoma may be critical for patient survivorship; however, the prognostic value of factors such as onset of symptoms or initiation of therapy in these patients has not been studied. This study sought to review the literature reporting treatment of osteosarcoma to determine the utility of event timing as a prognostic indicator. Due to significant heterogeneity in the literature, this study was conducted as a scoping review to assess the current state of the literature, identify strengths and weaknesses in current reporting practices, and to propose avenues for future improvement. MAIN BODY: This review screened 312 peer-reviewed studies of osteosarcoma in any anatomic location published in an English journal for reporting of an event timing metric of any kind in a population of 6 or more. Thirty-seven studies met inclusion/exclusion criteria and were assessed for level of evidence, quality, and event timing metric. Reviewers also collated: publication year, population size, population age, tumor site, tumor type, surgical treatment, and adjuvant medical treatment. Extracted event timing data were further characterized using nine standardized categories to enable systematic analysis. The reporting of event timing in the treatment of osteosarcoma was incomplete and heterogenous. Only 37 of 312 (11.9%) screened studies reported event timing in any capacity. The period between patient-reported symptom initiation and definitive diagnosis was the most reported (17/37, 45.9%). Symptom duration was the second most reported period (10/37, 27.0%). Event timing was typically reported incidentally and was never rigorously incorporated into data analysis or discussion. No studies considered the impact of event timing on a primary outcome. The six largest studies were assessed in detail to identify pearls for future researchers. Notable shortcomings included the inadequate reporting of the definition of an event timing period and the pooling of patients into poorly defined timing groups. CONCLUSIONS: Inconsistent reporting of event timing in osteosarcoma treatment prevents the development of clinically useful conclusions despite evidence to suggest event timing is a useful prognostic indicator. Consensus guidelines are necessary to improve uniformity and utility in the reporting of event timing
Route Guidance Map for Emergency Evacuation
An efficient process of emergency evacuation must be guided. In the event of an evacuation instruction, a significant amount of time is spent by evacuees looking for a place of relative safety or an exit. Due to the ensuing stress and confusion evacuees try to follow others, consequently, all the exits are not used effectively. Therefore, it is important to develop a route guidance map for the emergency. The focus of the map is to help both, the evacuees and the authorities to perform evacuation efficiently. This paper presents a route guidance map for pedestrians that aims an efficient evacuation in case of an emergency. An agent-based simulation framework is used for the simulation of various scenarios to prepare the guiding map. A real world case study of Sarojini Nagar, Delhi is presented to test the presented methodology. Eventually, several strategic recommendations are provided for improving safety of existing infrastructure
Risk Factors for Early Subsequent (Revision or Contralateral) ACL Reconstruction: A Retrospective Database Study
BACKGROUND: Many factors contribute to the risk for subsequent anterior cruciate ligament reconstruction (ACLR) within 2 years from the index procedure.
PURPOSE/HYPOTHESIS: The purpose of this study was 2-fold: (1) to evaluate the incidence of subsequent (revision or contralateral) ACLR at 2 years in a large cohort and (2) to explore the association between patient-specific factors and early subsequent ACLR risk by age group. We hypothesize that 2-year subsequent (revision or contralateral) ACLR rates will be low and that risk factors for subsequent (revision or contralateral) ACLR will vary depending on a patient\u27s age group.
STUDY DESIGN: Case-control study; Level of evidence, 3.
METHODS: The California Office of Statewide Health Planning and Development Ambulatory Surgery Database was retrospectively reviewed to assess the incidence of 2-year subsequent (revision or contralateral) ACLR and to identify patient-specific risk factors for early subsequent (revision or contralateral) ACLR by age group between 2005 and 2014.
RESULTS: Of 94,108 patients included, the rate of subsequent (revision or contralateral) ACLR was highest in patients younger than 21 years (2.4 per 100 person-years; 95% CI, 2.3-2.6) and lowest in those older than 40 years (1.3 per 100 person-years; 95% CI, 1.2-1.4). Younger age, white race (compared with Hispanic in all age groups and Asian in age40 years), private insurance if age younger than 21 years, public insurance or worker\u27s compensation claims if age older than 30 years were significantly associated with an increased risk of subsequent (revision or contralateral) ACLR at 2 years.
CONCLUSION: Results of the present study provide insight into subsequent (revision or contralateral) ACL reconstruction, which can be used to assess and modify treatment for at-risk patients and highlight the need for data mining to generate clinically applicable research using national and international databases
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