Search Results (58)

Swirling-flow instabilities in hydraulic turbine diffusers constitute a major operational challenge, particularly when Francis turbines operate under part-load conditions. Over the past decades, numerous control strategies have been proposed to mitigate the instabilities associated with swirling flows. This study presents a comprehensive numerical analysis of a passive flow-control technique based on an adjustable diaphragm device, referred to as IRiS. The primary objectives are to attenuate swirling-flow instabilities and to enhance energy recovery within the draft tube. Three-dimensional unsteady flow simulations were performed for multiple IRiS configurations, characterized by different shutter area ratios. The results indicate that the IRiS device can reduce pressure pulsation amplitudes by up to 60% while simultaneously improving pressure recovery. However, the simulations also show that hydraulic losses may increase at part-load operation, depending on the selected IRiS shutter opening. Overall, the findings support the applicability of this passive control concept for both new and rehabilitated Francis turbines operating under off-design conditions, far from the best efficiency point. Full article

Prostate cancer (PCa) is one of the most common malignancies in men and remains a major cause of cancer-related death worldwide. Radiotherapy is a well-established treatment modality for PCa, offering clinical outcomes comparable to surgical approaches. In recent years, stereotactic body radiotherapy (SBRT), characterized by the delivery of high radiation doses in a limited number of fractions, has been increasingly adopted as a standard approach in the treatment of prostate cancer, due to its favorable efficacy and toxicity profile. CyberKnife (CK) is one of the most commonly used hypofractionated radiotherapy techniques. This preliminary study aimed to evaluate and compare the radiation dose delivery and treatment time of CK-based SBRT using two different collimation systems: the multileaf collimator (MLC) and the IRIS variable aperture collimator, a dynamic device that adjusts its opening to simulate different circular field sizes. A total of 19 patients with low-to-intermediate-risk PCa were selected and treated at the Radiation Oncology Department of the National Cancer Institute IRCCS Fondazione G. Pascale in Naples between January 2024 and January 2025. For each patient, two treatment plans were generated—one with the IRIS collimator and one with the MLC. The results demonstrated that the use of the MLC significantly reduced treatment time while maintaining dosimetric quality comparable to IRIS-based plans. These findings support the clinical benefit of MLC implementation in prostate SBRT with the CK system. Full article

Field-programmable gate arrays (FPGAs) are increasingly used to bring biometric recognition from cloud- or GPU-centric deployments to resource-constrained edge devices where latency, power, and privacy are critical. This paper surveys recent (2021–2025) FPGA and FPGA-SoC implementations across five widely deployed modalities: face, fingerprint, iris, speaker (voiceprint), and finger vein. For each modality, we summarize representative implementations and the performance figures commonly reported in the literature (e.g., accuracy or EER, latency/throughput, resource usage, and power), highlighting the algorithm–hardware co-design choices that enable real-time operation. Across modalities, successful designs repeatedly employ streaming/dataflow architectures, aggressive quantization and fixed-point arithmetic, reuse-aware buffering, and heterogeneous CPU–FPGA partitioning, often supported by high-level synthesis and vendor deep learning IP. Beyond throughput, we discuss how FPGAs facilitate privacy-preserving on-device processing and can integrate template protection and presentation attack detection within the same fabric. Finally, we identify open challenges related to scalability to larger models, memory-bandwidth constraints, and design productivity, and outline research directions enabled by emerging adaptive FPGA architectures and more automated toolflows. Overall, the surveyed evidence indicates that FPGAs are a compelling platform for deterministic, energy-efficient, and secure biometric inference at the sensor edge. Full article

In the big-data-driven artificial intelligence era, similarity search, as a core operation in machine learning and data mining, demands high speed, energy efficiency, and scenario adaptability. Conventional electronic content-addressable memory (ECAMs) suffer from inherent RC delay bottlenecks, whereas existing optical content-addressable memory (OCAMs) are restricted by fixed bit-widths and limited distance metrics. In this work, we propose a variable bit-width all-optical CAM leveraging multi-segment modulators and phase-change material (PCM) Sb₂Se₃. The multi-segment memory unit (MSMU) therein compresses N-bit binary data into a single analog photonic unit, supporting direct data writing/loading without digital-to-analog converters (DACs) and flexible trade-offs between precision, storage capacity, noise immunity, and energy while enabling Hamming and nonlinear distance metrics. A six-element three-bit OCAM prototype was fabricated on a silicon nitride silicon-on-insulator (SiN-SOI) platform. Despite the absence of integrated high-speed phase shifters, the device still achieves reliable optical data storage and retrieval. K-nearest neighbor (kNN) simulations based on experimentally derived statistical data—validated on the iris, wine, and breast cancer datasets—show that the three-bit operating mode achieves classification accuracy comparable to Manhattan/Euclidean distances at high signal-to-noise ratios (SNRs), while the one-bit mode exhibits strong noise robustness. Energy consumption is 364 fJ/bit (3-bit) and 890 fJ/bit (1-bit). This work provides a high-speed, energy-efficient, and reconfigurable all-optical similarity search solution with experimentally verified device performance and dataset-validated applicability, showing great potential for widespread deployment in data-intensive machine learning and data-mining applications. Full article

By emulating the morphological structures of organisms, bionic robots achieve enhanced locomotion efficiency, stability, and environmental adaptability. Inspired by insect morphology and biological locomotion mechanisms, a wheel-legged transformation device for a hexapedal robot is proposed in this work. First, an iris-type wheel-legged transformation mechanism is designed. Subsequently, the operational principle of the iris–link composite mechanism is analyzed, and kinematic modeling of the transformation process is conducted. Finally, joint angle rotation, positional variation, and their effects under different gait states are examined through simulation of three typical gait patterns. Experimental results demonstrate that the proposed design significantly improves the motion stability of the bionic hexapedal robot. Furthermore, the adoption of a hollow leg structure reduces weight while enhancing locomotion flexibility, thereby strengthening the robot’s overall capability to respond to external disturbances. In summary, this study offers a valuable reference for the future development of wheel-legged transformable bionic robots. Full article

Background/Objectives: Cardiac implantable electronic device-related infective endocarditis (CIED-RIE) is a serious condition with significant morbidity and mortality. Although recent advances in imaging and therapeutic approaches have improved management, diagnosing and treating CIED-RIE continues to be challenging. This study aimed to identify factors associated with mortality in CIED-RIE patients. Methods: We conducted a retrospective, multicenter international study of adult patients diagnosed with CIED-RIE between January 2014 and June 2024. Data on demographics, clinical presentation, microbiological findings, imaging results, treatment modalities, and outcomes were collected and analyzed to determine predictors of short-term mortality. Results: A total of 197 patients (mean age: 65.3 ± 14.4 years; 75.1% male) were included. The most common device type was permanent pacemaker (48.2%). Staphylococcus species were the predominant pathogens (62.4%). Surgical intervention was performed in 67.5% of patients, and 90-day mortality occurred in 19.3%. Multivariable analysis identified higher Charlson comorbidity index (HR: 1.31), tricuspid valve involvement (HR: 2.35), vegetation size ≥ 10 mm (HR: 2.53), pulmonary embolism (HR: 3.92), and absence of surgical intervention (HR: 2.90) as independent predictors of increased 90-day mortality. Conclusions: Early identification of high-risk patients and prompt multidisciplinary management, including surgical intervention when indicated, are critical to improving outcomes in patients with CIED-RIE. Full article

The application of non-thermal (cold) plasmas is considered an environmentally friendly method that could affect plant metabolism and cellular development or can be used for the commercial production of natural products that cannot be chemically synthesized. In the present study, the non-embryogenic callus of iris (Iris reichenbachii Heuff.) was treated with a Radio Frequency (RF) plasma needle device using He as a working gas. We investigated short-term (up to seven days) and long-term (up to one year) changes on morphological, physiological and biochemical levels. An increased production of O₂⁻ and H₂O₂ was observed in the callus tissue after plasma treatment. The enzymes SOD and CAT represented the frontline in the antioxidant defense against reactive oxygen species (ROS) produced during the first hour of treatment, while POX was the leading antioxidant enzyme seven days after plasma treatment. Significant long-term morphological changes were observed in the calli due to the increased mitotic activity of the plant cells. In addition, three flavonoids (naringenin, apigenin and acacetin) and two isoflavonoids (irisolidone and irilone) were detected only in the plasma-treated tissue even one year after plasma treatment. The present study emphasizes the application of the plasma technique to promote meristematic activity and stimulate the production of specialized metabolites in iris calli. Full article

Background: It has been suggested that the mandible may differ according to gender. The fact that the mandible and the anatomical structures on it show various changes with age and gender differences is important in gender and age determination. The aim of this study was to evaluate the morphometric variation in the condyle and coronoid processes and the gonial angle, which are anatomical structures forming the mandible, with gender and age. Methods: Cone beam CT images of 141 individuals (78 female, 63 male) were used in this study. The images of all patients were obtained with the same X-ray device; the images were obtained at 70 kVp, 10 mA, and a 32 s exposure time in accordance with the manufacturer’s recommendations. Images displayed with 0.3 mm voxel with the IRYS 15.0 program were examined in the axial, sagittal, and coronal planes, and measurements were taken. The gonial angle, coronoid notch, condyle height, condyle–coronoid distance, and sigmoid notch depths were evaluated. Results: The average age of 141 individuals was 43.21 ± 15.96 years, and 55.3% of them were female and 44.7% were male. The mean right gonial angle in females (128.66 ± 5.50°) was significantly higher than in males (125.68 ± 5.10°) (p < 0.005). Similarly, the mean left gonial angle in females (128.84 ± 5.97°) was significantly higher than in males (125.26 ± 4.89°) (p < 0.005). The sigmoid notch depth was found to be greater in men, with an average of 13.88 ± 2.46 mm, while in women, it had an average of 13.13 ± 1.80 mm, and this difference was statistically significant (p < 0.005). The relationship between the two sides’ coronoid notch height, sigmoid notch depth, condyle height, and condyle–coronoid distance and age groups was not statistically significant (p > 0.005). Conclusions: Overall, our findings indicate that the male mandible may have a longer condyle, a narrower gonial angle, and a wider sigmoid notch depth than that of females. It has been observed that ramus measurements such as condyle length and sigmoid notch depth may be important in gender discrimination, and the male mandible exhibits larger values in these parameters. No differences in parameters were observed between age groups. Full article

Pupil segmentation in visible-light (RGB) images presents unique challenges due to variable lighting conditions, diverse eye colors, and poor contrast between iris and pupil, particularly in individuals with dark irises. While near-infrared (NIR) imaging has been the traditional solution for eye-tracking systems, the accessibility and practicality of RGB-based solutions make them attractive for widespread adoption in consumer devices. This paper presents a baseline for RGB pupil segmentation by adapting the Segment Anything Model (SAM). We introduce a multi-stage fine-tuning approach that leverages SAM’s exceptional generalization capabilities, further enhancing its elemental capacity for accurate pupil segmentation. The staged approach consists of SAM-BaseIris for enhanced iris detection, SAM-RefinedIris for improving iris segmentation with automated bounding box prompts, and SAM-RefinedPupil for precise pupil segmentation. Our method was evaluated on three standard visible-light datasets: UBIRIS.v2, I-Social DB, and MICHE-I. The results demonstrate robust performance across diverse lighting conditions and eye colors. Our method achieves near SOTA results for iris segmentation and attains mean mIOU and DICE scores of 79.37 and 87.79, respectively, for pupil segmentation across the evaluated datasets. This work establishes a strong foundation for RGB-based eye-tracking systems and demonstrates the potential of adapting foundation models for specialized medical imaging tasks. Full article

With advancements in hardware, high-quality head-mounted display (HMD) devices are being developed by numerous companies, driving increased consumer interest in AR, VR, and MR applications. This proliferation of HMD devices opens up possibilities for a wide range of applications beyond entertainment. Most commercially available HMD devices are equipped with internal inward-facing cameras to record the periocular areas. Given the nature of these devices and captured data, many applications such as biometric authentication and gaze analysis become feasible. To effectively explore the potential of HMDs for these diverse use-cases and to enhance the corresponding techniques, it is essential to have an HMD dataset that captures realistic scenarios. In this work, we present a new dataset of periocular videos acquired using a virtual reality headset called VRBiom. The VRBiom, targeted at biometric applications, consists of 900 short videos acquired from 25 individuals recorded in the NIR spectrum. These 10 s long videos have been captured using the internal tracking cameras of Meta Quest Pro at 72 FPS. To encompass real-world variations, the dataset includes recordings under three gaze conditions: steady, moving, and partially closed eyes. We have also ensured an equal split of recordings without and with glasses to facilitate the analysis of eye-wear. These videos, characterized by non-frontal views of the eye and relatively low spatial resolutions ($400\times 400$), can be instrumental in advancing state-of-the-art research across various biometric applications. The VRBiom dataset can be utilized to evaluate, train, or adapt models for biometric use-cases such as iris and/or periocular recognition and associated sub-tasks such as detection and semantic segmentation. In addition to data from real individuals, we have included around 1100 presentation attacks constructed from 92 PA instruments. These PAIs fall into six categories constructed through combinations of print attacks (real and synthetic identities), fake 3D eyeballs, plastic eyes, and various types of masks and mannequins. These PA videos, combined with genuine (bona fide) data, can be utilized to address concerns related to spoofing, which is a significant threat if these devices are to be used for authentication. The VRBiom dataset is publicly available for research purposes related to biometric applications only. Full article

The determination of sulcus-to-sulcus measurements has been challenging due to the limitations of current approaches. Ultrasound methods are highly operator-dependent and require extensive training, while traditional optical devices cannot visualize structures posterior to the iris. However, modern optical anterior segment coherence tomography (AS-OCT) devices are changing this paradigm by identifying some anatomical landmarks posterior to the iris. This study evaluates the reproducibility of optical sulcus measurements in the context of sizing a novel accommodative intraocular lens (IOL). Preoperative OCT scans of patients scheduled for cataract surgery were analyzed regarding the dimensions of the ciliary sulcus using a custom scan method with a clinically available anterior segment optical coherence tomographer. Measurements were compared between two different readers, and various derived parameters were compared. The measurements by both readers were highly correlated (R² > 0.96), and their agreement was excellent (mean difference 0.02 mm with 95% limits of agreement from −0.11 to 0.15 mm). In contrast, the sulcus diameter measurement did not agree well with automatically calculated values, such as the anterior chamber width or white-to-white. This leads to the conclusion that modern swept-source AS-OCT measurements of the ciliary sulcus dimensions are feasible, reproducible, and may be a clinically useful tool. Full article

Engineer-to-order manufacturing, characterized by highly customized products and complex workflows, presents unique challenges for warehouse management and operational efficiency. This paper explores the potential of a digital twin as a transformative solution for engineer-to-order environments in manufacturing companies realizing prefabricated building components. This paper outlines a methodology encompassing users’ requirements and the design to support the development of a digital twin that integrates Internet of Things devices, Building Information Modeling, and artificial intelligence capabilities. It delves into the specific challenges of outdoor warehouse optimization and worker safety within the context of engineer-to-order manufacturing, and how the digital twin aims to address these issues through data collection, analysis, and visualization. The research is conducted through an in-depth analysis of the warehouse of Focchi S.p.A., a leading manufacturer of high-tech prefabricated building envelopes. Focchi’s production processes and stakeholder interactions are investigated, and the paper identifies key user groups and their multiple requirements for warehouse improvement. It also examines the potential of the digital twin to streamline communication, improve decision-making, and enhance safety protocols. While preliminary testing results are not yet available, the paper concludes by underlining the significant opportunities offered by a BIM-, IoT-, and AI-powered digital twin for engineer-to-order manufacturers. This research, developed within the IRIS project, serves as a promising model for integrating digital technologies into complex warehouse environments, paving the way for increased efficiency, safety, and ultimately, a competitive edge in the market of manufacturing companies working in the construction industry. Full article

Implant-related infections (IRIs) represent a significant challenge to modern surgery. The occurrence of these infections is due to the ability of pathogens to aggregate and form biofilms, which presents a challenge to both the diagnosis and subsequent treatment of the infection. Biofilms provide pathogens with protection from the host immune response and antibiotics, making detection difficult and complicating both single-stage and two-stage revision procedures. This narrative review examines advanced chemical antibiofilm techniques with the aim of improving the detection and identification of pathogens in IRIs. The articles included in this review were selected from databases such as PubMed, Scopus, MDPI and SpringerLink, which focus on recent studies evaluating the efficacy and enhanced accuracy of microbiological sampling and culture following the use of chemical antibiofilm. Although promising results have been achieved with the successful application of some antibiofilm chemical pre-treatment methods, mainly in orthopedics and in cardiovascular surgery, further research is required to optimize and expand their routine use in the clinical setting. This is necessary to ensure their safety, efficacy and integration into diagnostic protocols. Future studies should focus on standardizing these techniques and evaluating their effectiveness in large-scale clinical trials. This review emphasizes the importance of interdisciplinary collaboration in developing reliable diagnostic tools and highlights the need for innovative approaches to improve outcomes for patients undergoing both single-stage and two-stage revision surgery for implant-related infections. Full article

Internet of Things (IoT) technology is evolving over the peak of smart infrastructure with the participation of IoT devices in a wide range of applications. Traditional IoT authentication methods are vulnerable to threats due to wireless data transmission. However, IoT devices are resource- and energy-constrained, so building lightweight security that provides stronger authentication is essential. This paper proposes a novel, two-layered multi-factor authentication (2L-MFA) framework using blockchain to enhance IoT devices and user security. The first level of authentication is for IoT devices, one that considers secret keys, geographical location, and physically unclonable function (PUF). Proof-of-authentication (PoAh) and elliptic curve Diffie–Hellman are followed for lightweight and low latency support. Second-level authentication for IoT users, which are sub-categorized into four levels, each defined by specific factors such as identity, password, and biometrics. The first level involves a matrix-based password; the second level utilizes the elliptic curve digital signature algorithm (ECDSA); and levels 3 and 4 are secured with iris and finger vein, providing comprehensive and robust authentication. We deployed fuzzy logic to validate the authentication and make the system more robust. The 2L-MFA model significantly improves performance, reducing registration, login, and authentication times by up to 25%, 50%, and 25%, respectively, facilitating quicker cloud access post-authentication and enhancing overall efficiency. Full article

Objectives: The aim of this review paper is to summarise surgical options available for repairing iris defects at the iris–lens plane, focusing on suturing techniques, iridodialysis repair, and prosthetic iris devices. Methods: A thorough literature search was conducted using multiple databases, including Medline, PubMed, Web of Science Core Collection, and the Cochrane Library, from inception to February 2024. Relevant studies were screened based on predefined criteria, and primary references cited in selected articles were also reviewed. Results: Various surgical techniques were identified for iris defect repair. Suturing methods such as interrupted full-thickness sutures and the McCannel technique offer solutions for smaller defects, while iridodialysis repair techniques address detachment of the iris from the ciliary body. Prosthetic iris devices, including iris–lens diaphragm devices, endocapsular capsular tension ring-based devices, and customizable artificial iris implants, provide options for larger defects, each with its own advantages and limitations. Conclusions: Successful iris reconstruction requires a personalised approach considering factors like defect size, ocular comorbidities, and patient preference. Surgeons must possess a thorough understanding of available techniques and prosthetic devices to achieve optimal outcomes in terms of both visual function and, nonetheless, cosmetic appearance. Full article