Article
Multidisciplinary Sciences
Qinying Huang, Jinying Li
Summary: This study aimed to compare the effects of Idiopathic epiretinal membrane (iERM) removal with or without internal limiting membrane (ILM) peeling on visual acuity and central macular thickness. The short-term benefits of ILM peeling for BCVA improvement and reduction of ERM recurrence were observed, but long-term changes in BCVA and CMT were similar with or without ILM peeling. Further large scale randomized trials with functional measures are needed to confirm these findings.
Article
Ophthalmology
Lekha K. Mukkamala, Jaycob Avaylon, R. Joel Welch, Amirfarbod Yazdanyar, Parisa Emami-Naeini, Sophia Wong, Jordan Storkersen, Jessica Loo, David Cunefare, Sina Farsiu, Ala Moshiri, Susanna S. Park, Glenn Yiu
Summary: The study suggests that intraoperative changes in retinal thickness may predict anatomic and visual outcomes after idiopathic ERM peeling surgery. Eyes undergoing greater iCMT changes were associated with greater CMT reduction, while those undergoing greater intraoperative thinning showed a trend toward better VA outcomes.
TRANSLATIONAL VISION SCIENCE & TECHNOLOGY
(2021)
Article
Medicine, General & Internal
Thanh-Tin P. Nguyen, Shuibin Ni, Guangru Liang, Shanjida Khan, Xiang Wei, Alison Skalet, Susan Ostmo, Michael F. Chiang, Yali Jia, David Huang, Yifan Jian, J. Peter Campbell
Summary: OCT has changed the standard of care for macular diseases in adults, but commercially available systems have a narrow FOV limiting their application to peripheral pathologies; OCT-based evaluation can improve diagnosis of all types of retinal detachment.
FRONTIERS IN MEDICINE
(2022)
Article
Medicine, General & Internal
Lisa Toto, Maria Ludovica Ruggeri, Federica Evangelista, Chiara Trivigno, Rossella D'Aloisio, Chiara De Nicola, Pasquale Viggiano, Emanuele Doronzo, Marta Di Nicola, Annamaria Porreca, Rodolfo Mastropasqua
Summary: This study investigates the parameters of optical coherence tomography (OCT) and OCT angiography (OCTA) in patients with neovascular age-related macular degeneration (nAMD) and macular neovascularization (MNV) types 1, 2, and 3. The results showed significant differences in CVI, CMT, and ORCCFA between MNV 1 and the other two groups. CVI was significantly different between MNV 1 and healthy controls and between MNV 1 and MNV 2. ORCCFA and CMT were significantly different between MNV 1 and MNV 2. There was no statistically significant difference in subfoveal choroidal thickness (SFCT) among the three groups.
JOURNAL OF CLINICAL MEDICINE
(2023)
Article
Optics
Daewoon Seong, Won Ki, Pilun Kim, Jaeyul Lee, Sangyeob Han, Soojin Yi, Hong Kyun Kim, Mansik Jeon, Jeehyun Kim
Summary: This study developed a virtual intraoperative OCT angiography integrated surgical microscope, which can simultaneously visualize the morphological tissue structure and microvasculature data of the surgical region, demonstrating its potential application in in vivo imaging and simulated surgeries of small animals.
OPTICS AND LASERS IN ENGINEERING
(2022)
Article
Ophthalmology
Kun Xiong, Xia Gong, Wangting Li, Yuting Li, Jie Meng, Langhua Wang, Wei Wang, Huang Wenyong
Summary: This study aimed to establish normative macular thickness data in Chinese individuals aged 30 to 80 years using swept-source optical coherence tomography (SS-OCT) and compared the measurements with spectral-domain OCT (SD-OCT). Results showed that SS-OCT measurements were significantly thinner than SD-OCT, but the agreement between the two devices was excellent, with conversion equations derived to translate measurements between them.
CURRENT EYE RESEARCH
(2021)
Article
Biochemical Research Methods
Michael Sommersperger, Jakob Weiss, M. Ali Nasseri, Peter Gehlbach, Iulian Iordachita, Nassir Navab
Summary: The emergence of robotics enables previously infeasible ophthalmic microsurgical procedures, with recent advances in iOCT allowing for 4D image-guided surgery. A novel method using a CNN to precisely estimate the distance between the injection needle and retinal layer boundaries demonstrates robustness to noise and provides distance feedback at an average update rate of 15.66 Hz.
BIOMEDICAL OPTICS EXPRESS
(2021)
Article
Engineering, Biomedical
Pedro Tana-Sanz, Maria Ruiz-Santos, Maria Dolores Rodriguez-Carrillo, Salvador Aguilar-Corcoles, Robert Montes-Mico, Pedro Tana-Rivero
Summary: The study evaluated the agreement of different biometric parameters obtained using intraoperative spectral-domain optical coherence tomography (SD-OCT) and two swept-source optical coherence tomography (SS-OCT) based biometers. Results showed that SS-OCT biometers demonstrated good agreement for anterior chamber depth (ACD), central corneal thickness (CCT), white-to-white (WTW) and lens thickness (LT), while SD-OCT showed discrepancies in ACD, CCT, and WTW values compared to SS-OCT biometers, but excellent agreement in LT measurements.
EXPERT REVIEW OF MEDICAL DEVICES
(2021)
Review
Optics
Christoph Krafft, Jurgen Popp
Summary: Modern optical and spectral technologies have the potential to characterize tissues at a molecular level, enabling the identification of pathological tissues and the grading and staging of tumors without the need for labeling. The current tools for intraoperative tumor assessment, as well as the requirements for tissue visualization from a medical and optical perspective, are described. Approaches utilizing optical and spectral techniques for ex vivo and in vivo monitoring are introduced, and proof-of-concept studies utilizing linear and nonlinear spectroscopy and imaging modalities are presented. The use of modern artificial intelligence and deep learning concepts to analyze spectroscopic and imaging datasets has contributed to the advancements in each technique. Finally, the article provides an outlook on the opportunities and prospects of clinical translation.
Article
Ophthalmology
Anna Lentzsch, Laura Schoellhorn, Christel Schnorr, Robert Siggel, Sandra Liakopoulos
Summary: This study compared swept-source (SS) and spectral-domain (SD) optical coherence tomography angiography (OCTA) for detecting macular neovascularization (MNV). The results showed that the sensitivity for MNV detection and agreement between devices was best when evaluating a combination of en face and cross-sectional OCTA.
GRAEFES ARCHIVE FOR CLINICAL AND EXPERIMENTAL OPHTHALMOLOGY
(2022)
Article
Medicine, General & Internal
Yiqi Chen, Yijun Xu, Xin Ye, Jiafeng Yu, Chenxi Wang, Zhengxi Zhang, Jianbo Mao, Lijun Shen
Summary: This study compared the changes in anatomical structure and visual function after idiopathic macular hole (iMH) treatment with internal limiting membrane (ILM) peeling and inverted ILM flap. The results showed that both techniques achieved a high closure rate, but the inverted ILM flap did not exhibit obvious advantages in anatomical morphology and visual function over ILM peeling.
FRONTIERS IN MEDICINE
(2023)
Article
Ophthalmology
Ruilin Zhu, Shiyu Xiao, Wenbo Zhang, Jun Li, Menglu Yang, Yadi Zhang, Xiaopeng Gu, Liu Yang
Summary: In this study, the retinal microstructural features of macular edema (ME) secondary to multiple etiologies were investigated using spectral-domain optical coherence tomography (SD-OCT). The results showed that hyperreflective foci (HRF) detected with SD-OCT were more common in diabetic macular edema (DME) patients compared to those with branch retinal vein occlusion-macular edema (BRVO-ME), central retinal vein occlusion-macular edema (CRVO-ME), or uveitic macular edema (UME). The occurrence of HRF was found to be correlated with the presence of hard exudates.
Article
Ophthalmology
Polina Astroz, Alexandra Miere, Francesca Amoroso, Oudy Semoun, Alexis Khorrami, Mayer Srour, Giuseppe Querques, Eric H. Souied
Summary: In this study, the prognostic significance of subretinal transient hyporeflectivity (STHR) in age-related macular degeneration was described and assessed. The results showed that STHR disappeared during short-term follow-up, but about 57.1% of eyes eventually developed exudative signs.
RETINA-THE JOURNAL OF RETINAL AND VITREOUS DISEASES
(2022)
Article
Biology
Shuo Chen, Da Ma, Sieun Lee, Timothy T. L. Yu, Gavin Xu, Donghuan Lu, Karteek Popuri, Myeong Jin Ju, Marinko Sarunic, Mirza Faisal Beg
Summary: This study introduces a segmentation-driven domain adaptation method for retinal imaging processing, which utilizes CycleGAN to improve domain adaptation. A two-stage pipeline is proposed to train a segmentation model in the source domain and adapt the images from the target domain. Experimental results demonstrate that the proposed method achieves improved segmentation performance and image quality.
COMPUTERS IN BIOLOGY AND MEDICINE
(2023)
Article
Neurosciences
Xing Wang, Peng Wang
Summary: This study aimed to observe the effects of three consecutive intravitreal injections of conbercept on neovascular age-related macular degeneration (nAMD) and explore the correlation between retinal anatomy and function using spectral-domain optical coherence tomography (SD-OCT) and electroretinography (ERG). The results showed that conbercept significantly improved visual acuity, restored retinal structure and function, and ERG could be used as an objective indicator to evaluate treatment efficacy and the need for retreatment.
FRONTIERS IN NEUROSCIENCE
(2023)
Article
Automation & Control Systems
Andrea Zanelli, Julian Kullick, Hisham M. Eldeeb, Gianluca Frison, Christoph M. Hackl, Moritz Diehl
Summary: This article presents the design and implementation of a current controller for a reluctance synchronous machine (RSM) based on continuous control set nonlinear model predictive control (NMPC). A computationally efficient gray box model, the Gaussian-linear-arctangent (GLA) model, is proposed and used for tracking formulation in the high-performance NMPC framework acados. The resulting controller is validated through simulation and deployment on a physical RSM. Experimental results demonstrate that the proposed implementation can achieve sampling times typical for electrical drives and significantly improve control performance compared to classical control strategies.
IEEE TRANSACTIONS ON CONTROL SYSTEMS TECHNOLOGY
(2022)
Article
Engineering, Electrical & Electronic
Ibrahim Harbi, Mostafa Ahmed, Christoph M. Hackl, Ralph Kennel, Mohamed Abdelrahem
Summary: This article proposes a novel hybrid nine-level inverter based on the popular five-level active-neutral-point-clamped topology. It reduces the required components and avoids the use of higher voltage switches while balancing the voltages of the flying capacitors through a voltage control strategy based on switching state redundancies.
IEEE TRANSACTIONS ON POWER ELECTRONICS
(2022)
Article
Energy & Fuels
Max A. Buettner, Niklas Monzen, Christoph M. Hackl
Summary: A novel artificial neural network-based optimal feedforward torque control strategy is proposed for Interior Permanent Magnet Synchronous Machines (IPMSMs) to compute the optimal reference currents. Compared to conventional methods, this strategy is faster, easier to implement, and can consider nonlinear characteristics of the machine, resulting in very accurate reference currents.
Article
Automation & Control Systems
Athina Birda, Christoph Grabher, Christoph M. Hackl, Joerg Reuss
Summary: This article derivates analytical expressions for the dc-link capacitor current and the inverter current for two-level VSIs feeding IPMSMs controlled by SOPWM. The effect of various pulse patterns on the inverter current and dc-link capacitor current ripples are evaluated through experimental results, validating the correctness of the derived expressions.
IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS
(2022)
Article
Multidisciplinary Sciences
Haotian Xie, Jianming Du, Dongliang Ke, Yingjie He, Fengxiang Wang, Christoph Hackl, Jose Rodriguez, Ralph Kennel
Summary: This article proposes a fast quadratic programming solver for multistep predictive current control. By rearranging the objective function and preselecting vectors close to the reference derivative, the number of searched switching states is significantly reduced, resulting in improved current control quality and computational efficiency.
Article
Green & Sustainable Science & Technology
Mostafa Ahmed, Ibrahim Harbi, Christoph M. Hackl, Ralph Kennel, Jose Rodriguez, Mohamed Abdelrahem
Summary: This paper discusses the MPPT based on finite-set model predictive control (FS-MPC) in photovoltaic (PV) systems. Two algorithms are developed to reduce the number of required sensors without altering the efficiency of FS-MPC. The first algorithm utilizes an accurate model of the PV system to estimate the output capacitor voltage, while the second algorithm utilizes an extended Kalman filter (EKF) to estimate the PV current. The proposed methodologies are compared with the conventional FS-MPC with full sensor utilization, and their robustness against parameter variation is examined. Validation is performed through simulation and experimental tests at different operating conditions.
IET RENEWABLE POWER GENERATION
(2022)
Article
Engineering, Electrical & Electronic
Issa Hammoud, Sebastian Hentzelt, Ke Xu, Thimo Oehlschlagel, Mohamed Abdelrahem, Christoph Hackl, Ralph Kennel
Summary: This article presents a real-time implementation of a continuous-control-set model predictive current controller for two types of permanent magnet synchronous machines. The constrained optimization problem is solved using a slack formulation, and the controller is tested on two different models of machines. The experimental results demonstrate that the controller performs well in electrical drive applications.
IEEE TRANSACTIONS ON POWER ELECTRONICS
(2022)
Article
Automation & Control Systems
Julian Kullick, Christoph M. Hackl
Summary: This paper presents a novel and simple approach for modeling, identification, and optimal torque control of induction machines. The approach utilizes a machine model that considers nonlinear flux linkages and iron losses, a machine identification procedure that produces temperature and frequency dependent machine maps, and an offline optimization method for generating optimal current references. Experimental results show that this approach can significantly improve the efficiency of induction machines.
IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS
(2023)
Article
Engineering, Electrical & Electronic
Ibrahim Harbi, Mostafa Ahmed, Christoph M. Hackl, Jose Rodriguez, Ralph Kennel, Mohamed Abdelrahem
Summary: This article proposes a dual-vector finite-control-set model predictive control (FCS-MPC) for a nine-level active neutral point clamped (ANPC) converter. The proposed control scheme reduces computational burden and coordinates multiple objectives effectively. Mathematical analysis and experimental implementation show that the proposed method outperforms other control methods in terms of steady-state errors, THDs, harmonic distribution, and execution times.
IEEE TRANSACTIONS ON POWER ELECTRONICS
(2023)
Review
Green & Sustainable Science & Technology
Zhao Song, Christoph M. M. Hackl, Abhinav Anand, Andre Thommessen, Jonas Petzschmann, Omar Kamel, Robert Braunbehrens, Anton Kaifel, Christian Roos, Stefan Hauptmann
Summary: The transition towards a sustainable and renewable-energy centered power system brings about significant challenges and requires a corresponding shift in operation strategies towards more intelligence and digitization. Digital twin systems (DTSs) have been identified as a promising approach for achieving optimal, reliable, and secure operation in power systems. This paper comprehensively reviews the applications of digital twins in power systems and proposes a generic definition of DTSs that can be further extended into a system of digital twin systems (SDTSs), enabling interaction and regulation between different DTSs through a central data and communication interface.
Article
Energy & Fuels
Simon Wiedemann, Christoph Michael Hackl
Summary: The proposed method allows for simultaneous estimation and compensation of nonlinear voltage deviations in voltage source inverters and synchronous machine models, using physically inspired structured artificial neural networks.
IEEE TRANSACTIONS ON ENERGY CONVERSION
(2023)
Article
Automation & Control Systems
Yuebin Pang, Jovan Knezevic, Daniel Glose, Christoph Hackl
Summary: This article investigates the impact of inaccuracies in inductances on the stability of sensorless control schemes for electrically excited synchronous machines in automotive applications. A compensation method is proposed to overcome this problem and ensure global convergence/stability of the observer, which is confirmed by experimental results on an EESM test bench.
IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS
(2023)
Article
Engineering, Electrical & Electronic
Felix Rojas, Cristobal Jerez, Christoph Michael Hackl, Oliver Kalmbach, Javier Pereda, Jonathan Lillo
Summary: MMCCs are a promising power electronics topology for high-power applications, but they are prone to faults due to high levels of thermal, electrical, and mechanical stress and a large number of components, reducing their reliability.
IEEE OPEN JOURNAL OF THE INDUSTRIAL ELECTRONICS SOCIETY
(2022)
Article
Engineering, Electrical & Electronic
Shih-Wei Su, Christoph M. Hackl, Ralph Kennel
Summary: Physically motivated and analytical prototype functions are proposed to approximate the nonlinear flux linkages of nonlinear synchronous machines. These functions can mimic various saturation effects and allow for easy calculation of differential inductances.
IEEE OPEN JOURNAL OF THE INDUSTRIAL ELECTRONICS SOCIETY
(2022)
Article
Engineering, Electrical & Electronic
Julian Kullick, Christoph M. Hackl
Summary: The study presents a speed-sensorless state-feedback controller for induction machines, which performs well under various operating conditions. Stability and performance improvements are achieved through pre-tuned observer and control gains.
