Academic literature on the topic 'Visual field base (VFL)'
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Journal articles on the topic "Visual field base (VFL)"
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Guijt, M. C., A. H. Zamanipoor Najafabadi, I. C. Notting, A. M. Pereira, M. J. T. Verstegen, N. R. Biermasz, W. R. van Furth, and K. M. J. A. Claessen. "Towards a pituitary apoplexy classification based on clinical presentation and patient journey." Endocrine 76, no. 1 (January 24, 2022): 132–41. http://dx.doi.org/10.1007/s12020-022-02983-3.
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Abstract Purpose The condition of pituitary apoplexia contains the clinical spectre from life-threatening emergency to asymptomatic self-limiting course, which partly determines diagnostic delay and management. Outcome evaluation of course and management of pituitary apoplexia is hampered by the diverse presentation of this condition and requires appraisal. This study aimed to describe the patient journey, clinical presentation, and management of various types of pituitary apoplexy in a new classification to facilitate future outcome evaluation and identify unmet needs in the care process. Methods A single-center retrospective patient chart study was conducted between 2005–2021 (N = 98). Outcome measures were clinical symptoms at first presentation in hospital, being headache, consciousness, visual acuity, visual field defects (VFD), ophthalmoplegia, nausea, vomiting, fever, and hypopituitarism and care process characteristics. Results Mean age was 47.6 ± 16.6 years (51.0% male). We describe their patient journey and identified three different types, differing in clinical presentation, in-hospital route, and final treatment, e.g., Acute (type A, 52%), Subacute (type B, 22.5%), and Non-acute (type C, 25.5%). Type A generally presents with acute onset headaches, VFD, or ophthalmoplegia emergency setting, with lowest mean visual acuity of both eyes and frequent hypocortisolism. Conclusions Pituitary apoplexy can be approached as a spectrum of disease with 3 main subtypes, with a different initial presentation, different in-hospital route resulting in different management. Acknowledging subtypes with particular needs for (emergency) referrals to Pituitary Tumors Center of Excellence (PTCOE) will serve patient care improvements, outcome evaluations and address areas for improvement.
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Ernest, Paul J. G., Jan S. A. G. Schouten, Henny J. M. Beckers, Fred Hendrikse, Martin H. Prins, and Carroll A. B. Webers. "The evidence base to select a method for assessing glaucomatous visual field progression." Acta Ophthalmologica 90, no. 2 (August 4, 2011): 101–8. http://dx.doi.org/10.1111/j.1755-3768.2011.02206.x.
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Alekseev, A. P., E. V. Goshin, N. S. Davydov, N. A. Ivliev, and A. V. Nikonorov. "Visual-inertial odometry algorithms on the base of thermal camera." Information Technology and Nanotechnology, no. 2416 (2019): 183–88. http://dx.doi.org/10.18287/1613-0073-2019-2416-183-188.
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A trajectory building based on a camera data is one of the most popular tasks in the field of machine vision. In particular, this task appears when it is necessary to navigate in the absence of signals from global navigation systems such as GLONASS and GPS. In this work, study of existing methods of visual odometry for the flight trajectory restoration by shooting an infrared camera of the thermal range were conducted. To improve the accuracy, it is proposed to use the data from inertial sensors. As a result, it is shown that the proposed solution allows to successfully solve the problem of trajectory reconstruction.
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Sharpe, James A. "Visual Dysfunction with Basal Skull Tumours." Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques 12, S4 (November 1985): 332–35. http://dx.doi.org/10.1017/s0317167100035472.
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ABSTRACT:Early detection of visual loss caused by tumours of the base of the skull is accomplished by systematic tests of the pregeniculate optic pathway. Even when central acuity is relatively preserved, a relative afferent pupillary defect and reduced color perception yield evidence of impaired optic nerve conduction. Although confrontation tests of the visual fields are useful screening techniques, unexplained symptoms should be pursued with static and kinetic perimetry. Patterns of optic nerve and chiasmal field loss and atrophy of the disc or retinal nerve fibers are imprecise guides to the location of basal skull tumours. Regardless of the pattern of visual field defect, unexplained progressive loss of vision demands intensive neuroradiologic study of the basal cisterns and skull.
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Fredes, Felipe, Gabriel Undurraga, Pablo Rojas, Felipe Constanzo, Carolina Lazcano, Jaime Pinto, and Thomas Schmidt. "Visual Outcomes after Endoscopic Pituitary Surgery in Patients Presenting with Preoperative Visual Deficits." Journal of Neurological Surgery Part B: Skull Base 78, no. 06 (July 19, 2017): 461–65. http://dx.doi.org/10.1055/s-0037-1604169.
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Introduction Pituitary adenomas represent 15% of primary brain tumors. Visual disturbance is a common clinical manifestation of these neoplasms due, among other factors, to local mass effect on the optic system. Objective To evaluate changes of the visual fields in patients undergoing endoscopic endonasal approach (EEA) for pituitary adenomas and to find predictive factors for successful visual field outcome. Material and Methods This is a cross-sectional study. A review was conducted of medical records of consecutive patients with tumors of the sellar region undergoing EEA between January 2008 and December 2012 at the Skull Base Unit of Guillermo Grant Benavente Hospital, University of Concepción, Concepción, Chile, and who had undergone pre- and postoperative visual field evaluation. Results A total of 35 patients, with a mean age of 50.2 years, fulfilled the inclusion criteria. All patients had objective visual field disturbances before the surgery. Following surgery, 25 patients (71.4%) had favorable outcomes, whereas 8 (22.8%) had no change and 2 (5.8%) had an unfavorable outcome. Complete tumor removal was associated with a better visual outcome than those obtained after a subtotal removal. Discussion The EEA for pituitary tumors is particularly effective for visual field disturbances, with reported improvement rates ranging from 50 to 90%. Our series show similar results, with a 71.4% improvement of visual field disturbances. Conclusion This study adds further evidence to the current belief that EEA for pituitary adenomas is a safe and effective technique to improve visual field alterations. Complete removal of the tumor during surgery seems to be a predictive factor for a good visual outcome.
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Bampoe, Joseph, Paul Ranalli, and Mark Bernstein. "Postoperative Reversal of Complete (Monocular) Blindness in Skull Base Meningioma: Case Report." Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques 30, no. 1 (February 2003): 72–74. http://dx.doi.org/10.1017/s0317167100002481.
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ABSTRACT:Background:Meningiomas of the anterior cranial fossa frequently present with impaired visual function. Recognition of this entity in the differential diagnosis of painless, progressive, and asymmetric optic neuropathy is important since reversal of visual loss is possible given timely surgical excision of the tumour.Methods:A 76-year-old man presented with no perception of light in his right eye and a reduced visual acuity of 20/60 in his left eye with a markedly constricted visual field. His visual deterioration had progressed over the previous three months and was not associated with headache. Ophthalmoscopy showed normal optic discs. MRI scanning showed a large frontal basal meningioma, which was subsequently resected.Results:The patient noticed an immediate improvement in his vision in his right eye. Visual acuity in his right eye improved to 20/50 at six weeks postoperatively and to 20/25 at five months, with corresponding improvement of the visual field.Conclusion:Complete monocular blindness due to tumour compressing or distorting the anterior visual pathways does not preclude recovery following timely decompressive surgery, especially when the appearance of the optic disc is normal.
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Holbrook, M. Cay. "Renewing and Refreshing Knowledge Base of the Field of Visual Impairment: A Call to Action." Journal of Visual Impairment & Blindness 109, no. 2 (March 2015): 159–62. http://dx.doi.org/10.1177/0145482x1510900213.
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Kiyofuji, Satoshi, Amanda M. Casabella, Christopher S. Graffeo, Avital Perry, James A. Garrity, and Michael J. Link. "Sphenoorbital meningioma: a unique skull base tumor. Surgical technique and results." Journal of Neurosurgery 133, no. 4 (October 2020): 1044–51. http://dx.doi.org/10.3171/2019.6.jns191158.
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OBJECTIVESphenoorbital meningioma (SOM) is a unique skull base tumor, characterized by infiltrative involvement and hyperostosis primarily of the lesser wing of sphenoid bone, with frequent involvement of the orbital compartment. SOM often manifests with proptosis and visual impairment. Surgical technique and outcome are highly variable among studies reported in the literature. The authors present a single-surgeon experience with SOM.METHODSA retrospective review of a prospectively maintained institutional database was performed. A blinded imaging review by 2 study team members was completed to confirm SOM, after which chart review was carried out to capture demographics and outcomes. All statistical testing was completed using JMP Pro version 14.1.0, with significance defined as p < 0.05.RESULTSForty-seven patients who underwent surgery between 2000 and 2017 were included. The median age at surgery was 47 years (range 36–70 years), 81% of patients were female, and the median follow-up was 43 months (range 0–175 months). All operations were performed via a frontotemporal craniotomy, orbitooptic osteotomy, and anterior clinoidectomy, with extensive resection of all involved bone and soft tissue. Preoperatively, proptosis was noted in 44 patients, 98% of whom improved. Twenty-eight patients (60%) had visual deficits before surgery, 21 (75%) of whom improved during follow-up. Visual field defect other than a central scotoma was the only prognostic factor for improvement in vision on multivariate analysis (p = 0.0062). Nine patients (19%) had recurrence or progression during follow-up.CONCLUSIONSSOM is a unique skull base tumor that needs careful planning to optimize outcome. Aggressive removal of involved bone and periorbita is crucial, and proptosis and visual field defect other than a central scotoma can improve after surgery.
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Slaboda, Jill C., Richard T. Lauer, and Emily A. Keshner. "Postural Responses of Adults With Cerebral Palsy to Combined Base of Support and Visual Field Rotation." IEEE Transactions on Neural Systems and Rehabilitation Engineering 21, no. 2 (March 2013): 218–24. http://dx.doi.org/10.1109/tnsre.2013.2246583.
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Streepey, Jefferson W., Robert V. Kenyon, and Emily A. Keshner. "Visual motion combined with base of support width reveals variable field dependency in healthy young adults." Experimental Brain Research 176, no. 1 (October 28, 2006): 182–87. http://dx.doi.org/10.1007/s00221-006-0677-2.
Full textBook chapters on the topic "Visual field base (VFL)"
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Lanzara, Emanuela. "Generative Design Strategies for Customizable Prototypes." In Advances in Media, Entertainment, and the Arts, 68–93. IGI Global, 2021. http://dx.doi.org/10.4018/978-1-7998-7254-2.ch004.
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This chapter shows some results of academic research and didactic activities about innovative design and productive processes based on modeling and digital fabrication integrated strategies. The results of these experiments are customizable lamps prototypes. Digital modeling is based on algorithmic-generative visual scripting approach and geometric theories to manage primitive or complex shapes and patterns to optimize digital manufacturing. The following paragraphs and sub-paragraphs describe a prototypes collection designed, manufactured, and assembled by students on their first experience in VPL and digital prototyping. Lamp prototypes are made using additive and subtractive techniques according to different shaping approaches. The main goal of this academic approach is to collaborate in design and architectural geometry research field: the main goal is to support training and entrepreneurial activities of students aimed at management of complex data systems according to new potential of digital tools for advanced shaping, new manufacturing processes, and ecological strategies.
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Arndt, T., S. K. Chang, A. Guerico, and P. Maresca. "An XML-Based Approach to Multimedia Engineering for Distance Learning." In Advances in Distance Education Technologies, 108–37. IGI Global, 2007. http://dx.doi.org/10.4018/978-1-59904-376-0.ch006.
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Multimedia software engineering (MSE) is a new frontier for both software engineering (SE) and visual languages (VL). In fact, multimedia software engineering can be considered as the discipline for systematic specification, design, substitution, and verification of visual patterns. Visual languages contribute to MSE such concepts as: Visual notation for software specification, design, and verification flow charts, ER diagrams, Petri nets, UML visualization, visual programming languages, etc. Multimedia software engineering and software engineering are like two sides of the same coin. On the one hand, we can apply software engineering principles to the design of multimedia systems. On the other hand, we can apply multimedia technologies to the software engineering practice. In this chapter, we concentrate on the first of these possibilities. One of the promising application areas for multimedia software engineering is distance learning. One aim of this chapter is to demonstrate how it is possible to design and to implement complex multimedia software systems for distance learning using a tele-action object transformer based on XML technology applying a component-based multimedia software engineering approach. The chapter shows a complete process of dataflow transformation that represents TAO in different ways (text, TAOML, etc.) and at different levels of abstraction. The transformation process is a reversible one. A component-based tool architecture is also discussed. We also show the first experiments conducted jointly using the TAOML_T tool. The use of an XML-based approach in the distance learning field has other advantages as well. It facilitates reuse of the teaching resources produced in preceding decades by universities, schools, research institutions, and companies by using metadata. The evolution of the technologies and methodologies underlying the Internet has provided the means to transport this material. On the other hand, standards for representing multimedia distance learning materials are currently evolving. Such standards are necessary in order to allow a representation which is independent of hardware and software platforms so that this material can be examined, for example, in a Web browser or so that it may be reused in whole or in part in other chapters of a book or sections of a course distinct from that for which it was originally developed. Initial experiments in reuse of distance learning carried out at the University of Naples, Kent State University, and Cleveland State University are described. The authors have also developed a collaboration environment through which the resources can be visualized and exchanged.
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Halland, Ingrid. "Introduction." In Ung Uro, 11–25. Cappelen Damm Akademisk/NOASP, 2021. http://dx.doi.org/10.23865/noasp.127.ch1.
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In Ung Uro: Unsettling Climates in Nordic Art, Architecture and Design, thirteen young writers, critics, and art historians examine how Nordic visual art, architecture, and design relate to the Anthropocene. The chapters in the book represent a new generation of scholarship in the field of visual studies, which holds that critique and analysis of artistic expression must have a different form and agency than before: less descriptive and impartial, according to objective parameters, and more speculative and insistent, in accordance with subjective experiences. By discussing the artwork Future Library: 2014–2114 by Katie Paterson, this introductory chapter presents key notions that run throughout the book: Arne Næss’ deep ecology, Donna Haraway’s ‘staying with the trouble’ and Giorgio Agamben’s notion of profanation. Further, chapter introduces how ethical criticality functions as a methodological underpinning for the authors’ interpretation and proposes the term deep relationalism as an analytical concept for describing a tendency in the Nordic arts in the latter part of the 2010s: an interest in processual works with an ethical value base directed towards destabilising human exceptionalism.
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Brumen, Boštjan. "Content Analysis of Medical and Health Apps’ Privacy Policies." In Frontiers in Artificial Intelligence and Applications. IOS Press, 2022. http://dx.doi.org/10.3233/faia210486.
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Privacy is a fundamental human right and is widely end extensively protected in the western industrialized world. The recent advances in technologies, especially in the use of applications developed and designed for mobile devices, have led to the rise of its abuse on one hand and a higher awareness of the importance of privacy on the other side. Legal texts protecting privacy have attempted to rectify some of the problems, but the ecosystem giants and mobile apps developers adapted. In this paper, we analyze which data mobile apps developers are collecting. We have focused on a sample of apps in the medical and health field. The research was done using collocations analysis. A relationship between a base word and its collocative partners was sought. The initial visual results have led us to more detailed studies that unveiled some worrying patterns. Namely, applications are collect data about the users and their activities, but also about their family members, medical diagnoses, treatments, and alike, going well beyond the “need to function” / functionality threshold.
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Sedlar, Patricia. "The Ubiquitous Grid." In Ubiquitous and Pervasive Computing, 35–43. IGI Global, 2010. http://dx.doi.org/10.4018/978-1-60566-960-1.ch004.
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Grid computing is an emerging technology providing the possibility to aggregate resources for the solution of computation- or data-intensive scientific tasks. Taking the evolution of mobile computing into consideration, new Grid concepts are conceivable, fully exploiting the advantage of mobile devices and ubiquitous access. By decoupling resource availability from the core grid infrastructure and hardware, the user has always the same computational power, data or storage available, regardless of a device or location. Thus restricted capabilities of thin clients can be extended and new fields of application can be made accessible. The key concept is “The invisible grid” – the grid environment should just be there for the use of applications in science, business, health care, environment, or culture domains. Having this concept in mind, the following scenario is conceivable: Equipped with your mobile phone, which you always have with you, you are walking around and are taking a picture of an object you are interested in. You are sending the picture to the grid, where the visual information is extracted. After the analysis, information about the captured object is sent to you. Thus you have a search engine on a visual base at your permanent disposal, information captured as seen by your eyes – without the need of textural translations or the need to know the object’s name or ID in order to retrieve information about it. Realizing the scenario above, the user obtains a smart tool, easing information retrieval considerably by making use of ubiquity in combination with grid computing. But the scenario has even more potential in terms of pervasiveness. The use of mobile devices can provide a user with additional location bound information. With a portable device the user is able to access location-based services or to collect environmental information to be processed within a grid. At this stage research activities in the field of pervasive computing comeinto play. Pervasive computing pursues the goal to enhance the environment with sensors and smart objects in order to provide the user with suitable context-based and/or location-based services. Expanding the introduced setting with the capabilities from pervasive computing, the following scenario is conceivable: You are an invited speaker on a conference and you are moving through the rooms of the venue. All rooms are equipped with cameras covering all perspectives of view. You are looking at a person from whom you want to know the research interests. You flick with your finger, to capture the camera picture from your perspective. The picture is processed within the grid and the ambient display next to you shows the requested information.
Conference papers on the topic "Visual field base (VFL)"
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Rutland, John W., Bradley N. Delman, Kuang-Han Huang, Gaurav Verma, Noah C. Benson, Dillan F. Villavisanis, Hung-Mo Lin, et al. "Primary Visual Cortical Thickness Correlates with Visual Field Defects in Patients with Pituitary Macroadenomas: A Structural 7-Tesla Retinotopic Analysis." In 30th Annual Meeting North American Skull Base Society. Georg Thieme Verlag KG, 2020. http://dx.doi.org/10.1055/s-0040-1702293.
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Keshner, Emily A., and Jill Slaboda. "Postural behaviors to combined disturbances of the visual field and base of support." In 2009 Virtual Rehabilitation International Conference. IEEE, 2009. http://dx.doi.org/10.1109/icvr.2009.5174221.
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Lebens, Mary. "Retail Quest: Student Perceptions of a Virtual Field Trip App." In InSITE 2022: Informing Science + IT Education Conferences. Informing Science Institute, 2022. http://dx.doi.org/10.28945/4945.
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Aim/Purpose: Two popular methods for encouraging active learning are Augmented Reality (AR) and Virtual Field Trips (VFTs). This exploratory case study examines college students’ perceptions of a prototype AR and VFT app as an active learning strategy. Background: AR allows students to learn as they physically explore a destination, while VFTs give students the opportunity to visit exciting destinations without leaving their homes. AR and VFTs promote active learning, which has been shown to increase college student success in Science, Technology, Engineering, and Math (STEM) courses. The aim of the VFT app in this study is to provide college students in a STEM course with an interactive lesson on modeling information systems using diagrams. Methodology: This exploratory case study is intended to serve as a condensed case study performed with the prototype version of a VFT app before implementing a large-scale investigation of students’ perceptions of a more refined version of the app. The study employed a qualitative approach involving a survey with open-ended questions to gather college students’ perceptions of learning with a VFT. The data were analyzed using inductive coding. The participants are students at a mid-sized, urban, public university. Contribution: This exploratory case study serves as a proof-of-concept and starting point for other faculty who may be interested in developing their own AR and VFT apps to engage students in active learning. Releasing the app to a common Open Educational Resources (OER) repository will give other faculty easy access to re-use the app and build upon it to create their own virtual field trips. OER are learning materials that are freely available for students and faculty to download and use in their coursework. Findings: Students overwhelmingly perceived the VFT app helped them learn about the subject that was presented, citing the visual nature of the app, the real-life scenarios presented in the app, and the app’s ease of use as reasons why. The majority (over 89%) also agreed that the app motivated them to learn more about the subject, mainly due to the app’s real-life scenarios, and over 83% of students cited at least one benefit to learning with the app, such as the navigation/location features, the easy-to-use interface, and the real-world scenarios. Recommendations for Practitioners: The pedagogical implications of this study are that faculty should adopt VFTs as an active learning strategy, particularly in STEM college courses, based on the students’ positive perceptions of learning, motivation, and benefits of VFTs. Recommendations for Researchers: Researchers can expand on this exploratory case study by conducting a larger-scale study of the VFT app employed in the case study, or by developing their own VFT app based on the one in this study, to capture a broader group of students’ perceptions of VFTs as an active learning strategy. Impact on Society: The broad impact of this research on society is encouraging the adoption of VFTs as an active learning strategy since active learning strategies are shown to increase college students’ success and engagement. Future Research: Future research will be conducted in subsequent terms to gather additional data on students’ perceptions of the VFT app, as well as their perceptions of the relationship between learning and the VFT technology. Further research is also needed to survey faculty on their perceptions of how engaging with the app impacts student learning, particularly in regards to the VFT technology within the app.
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Slaboda, Jill C., Richard T. Lauer, and Emily A. Keshner. "Postural responses of adults with cerebral palsy to combined base of support and visual field rotation." In 2011 International Conference on Virtual Rehabilitation (ICVR). IEEE, 2011. http://dx.doi.org/10.1109/icvr.2011.5971856.
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Gao, Chenyu, Qi Zhu, Peng Wang, and Qi Wu. "Chop Chop BERT: Visual Question Answering by Chopping VisualBERT’s Heads." In Thirtieth International Joint Conference on Artificial Intelligence {IJCAI-21}. California: International Joint Conferences on Artificial Intelligence Organization, 2021. http://dx.doi.org/10.24963/ijcai.2021/92.
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Vision-and-Language (VL) pre-training has shown great potential on many related downstream tasks, such as Visual Question Answering (VQA), one of the most popular problems in the VL field. All of these pre-trained models (such as VisualBERT, ViLBERT, LXMERT and UNITER) are built with Transformer, which extends the classical attention mechanism to multiple layers and heads. To investigate why and how these models work on VQA so well, in this paper we explore the roles of individual heads and layers in Transformer models when handling 12 different types of questions. Specifically, we manually remove (chop) heads (or layers) from a pre-trained VisualBERT model at a time, and test it on different levels of questions to record its performance. As shown in the interesting echelon shape of the result matrices, experiments reveal different heads and layers are responsible for different question types, with higher-level layers activated by higher-level visual reasoning questions. Based on this observation, we design a dynamic chopping module that can automatically remove heads and layers of the VisualBERT at an instance level when dealing with different questions. Our dynamic chopping module can effectively reduce the parameters of the original model by 50%, while only damaging the accuracy by less than 1% on the VQA task.
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Rao, Akash K., Chandan Satyarthi, Utkrisht Dhankar, Sushil Chandra, and Varun Dutt. "Indirect Visual Displays: Influence of Field-of-Views and Target-Distractor Base-Rates on Decision-Making in a Search-and-Shoot Task." In 2018 IEEE International Conference on Systems, Man, and Cybernetics (SMC). IEEE, 2018. http://dx.doi.org/10.1109/smc.2018.00731.
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Wiedemann, Matthias, Wolfram Remlinger, and Klaus Bengler. "Application of Galvanic Vestibular Stimulation for the Evaluation of Vehicle Settings in a Fixed-Base Simulator." In Applied Human Factors and Ergonomics Conference. AHFE International, 2021. http://dx.doi.org/10.54941/ahfe100665.
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Driving simulation is a well probed and accepted technology for virtual development in automotive engineering. In the usual driving task visual perception is the most important factor. However, for the evaluation of vehicle settings in the field of driving dynamics it is essential, not only to generate realistic visual, but also vestibular cues for the driver. Therefore, dynamic driving simulators are usually applied, though they are a costly investment.Galvanic Vestibular Stimulation (GVS) creates the impression of accelerations by influencing the human equilibrium organ. In flight and driving simulation successful implementations of GVS systems already exist, mainly with the focus on reducing simulator sickness or to improve driver’s adaption to the simulator.Here, a concept for linking a GVS system with a fixed-base driving simulator is introduced. First, the adaption of the GVS system to individual preferences is conducted. In a second step, the evaluation in terms of objective driving behavior and subjective survey data is investigated to describe the influence of the GVS induced acceleration perception. Experiments are run for the driver as well as the passenger role. As a result the experiment should prove, whether the user is enabled to differentiate between various vehicle settings in the field of driving dynamics, as it would be possible in a dynamic driving simulator.
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Bourret, Quentin, Pierre-Olivier Lemieux, Julie Charland, and Rachid Aissaoui. "Grasp Planning Of Unknown Object For Digital Human Model." In 13th International Conference on Applied Human Factors and Ergonomics (AHFE 2022). AHFE International, 2022. http://dx.doi.org/10.54941/ahfe1001908.
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ObjectiveGrasp planning is a popular topic in the fields of robotic and Digital Human Model (DHM) (4, 6, 7, 9, 10, 11). So far, the proposed planners do not consider the final posture of the DHM has a criteria when determining potential grasps. In (4), a grasping algorithm has been developed to automatically grasp known tools. The present work introduces a grasp planner for single-hand grasp on an unknown object, further referred as “part”.MethodThe grasp planner gives has a result a grasp pose (position + orientation) for the posture solver (Smart Posturing Engine) to reach. The input necessary to the grasp planner are the 3D model of the object to grasp and of the surrounding environment, and an initial manikin position that is automatically determines by the posture solver algorithm.First the part is approximated by its oriented bounding box (OBB), limiting the grasp poses to 6 (one for each face of the OBB). Then precise grasp types (5) and apertures are chosen based on the face’s dimensions (i.e. width and depth), ranging from a small face (i.e. pinch) to larger ones (i.e. medium wrap or precision sphere).To determine what is the best face of the OBB to grasp, accessibility checks are performed by validating that the space around the face is free of collision. The faces are checked using a specific order (i.e. top, right or left, bottom, front, back) that is determined using the relative initial position of the manikin. As soon as a face is found to be graspable and accessible, the algorithm stops and choose that face as the best one to grasp.Using the selected face target, the hand is positioned using an inverse kinematic solver, free to rotate around the target using extra hand degrees-of-freedom inside a limited range (4). Giving the posture solver more possibilities to find a realistic posture.ResultsThe grasp planner described above leaded to believable grasps for the simulated tasks as well as a believable overall DHM posture. Examples of postures will be shown on assembly tasks performed on a gearbox assembly line.DiscussionThe proposed grasp planner seems really promising. In its current form, it is most suitable for small parts and bigger ones well represented by their OBB. More complex and bigger parts may require further segmentation into multiple smaller sub-parts (9, 10), allowing to perform the proposed checks at more specific and believable locations on the object. This would allow to obtain grasps on a wider range of objects. The object weight is also important and is currently being added to grasp type selection. The present planner is used by the Smart Posture Engine (SPE) framework (1, 2 and 3) inside Dassault Systèmes application “Ergonomic Workplace Design”. With the Ergo4All (12) technology the SPE allows to assess and minimize ergonomic risks involved in simulated workplaces.1. Lemieux, P.-O., Barré, A., Hagemeister, N., Aissaoui, R.: Degrees of freedom coupling adapted to the upper limb of a digital human model. Int. J. Hum. Factors Model. Simul. 5(4), 314–337 (2017)2. Lemieux, P., Cauffiez,M., Barré, A., Hagemeister, N., Aissaoui, R.: A visual acuity constraint for digital human modeling. In: 4th Conference proceedings (2016)3. Zeighami, A., Lemieux, P., Charland, J., Hagemeister, N., Aissaoui, A.: Stepping behavior for stability control of a digital human model. ISB/ASB (2019)4. Bourret, Q., Lemieux, P., Hagemeister, N., Aissaoui, R.: Flexible hand posture for tools grasping. DHM (2019)5. FEIX, Thomas, ROMERO, Javier, SCHMIEDMAYER, Heinz-Bodo, et al. The grasp taxonomy of human grasp types. IEEE Transactions on human-machine systems, 2015, vol. 46, no 1, p. 66-77.6. BEKEY, George A., LIU, Huan, TOMOVIC, Rajko, et al. Knowledge-based control of grasping in robot hands using heuristics from human motor skills. IEEE Transactions on Robotics and Automation, 1993, vol. 9, no 6, p. 709-722.7. Holleman, C.; Kavraki, L.E.; A framework for using the workspace medial axis in PRM planners, in Proceedings 2000 ICRA. Millennium Conference. IEEE International Conference on Robotics and Automation. Symposia Proceedings (Cat. No. 00CH37065), IEEE, Vol 2, 2000, 1408-1413. https://doi.org/10.1109/ROBOT.2000.8447958. FEIX, Thomas, BULLOCK, Ian M., et DOLLAR, Aaron M. Analysis of human grasping behavior: Correlating tasks, objects and grasps. IEEE transactions on haptics, 2014, vol. 7, no 4, p. 430-4419. Díaz, C.; Puente, S.; Torres, F.; Grasping points for handle objects in a cooperative disassembly system, IFAC Proceedings Volumes, 40(2), 2007, 112-117. https://doi.org/10.3182/20070523-3-ES-4907.0002010. Miller, A.T., Knoop, S., Christensen, H.I. and Allen, P.K., Automatic grasp planning using shape primitives. in Robotics and Automation, 2003. Proceedings. ICRA'03. IEEE International Conference on, (2003), IEEE, 1824-1829.11. Goussous, Faisal Amer. Grasp planning for digital humans. The University of Iowa, 2007.12. Bourret, Quentin, et al. "Ergo4All: An Ergonomic Guid
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Yang, Zhengmao, Youyou Wu, Jens P. Tronskar, and Daqin Xu. "Fatigue Crack Growth Rate Testing for Clad and Lined Pipe Girth Weld." In ASME 2019 38th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/omae2019-95500.
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Abstract The Direct Current Potential Drop (DCPD) method is a common method used to detect the initiation of cracks, measure crack growth rates and monitor crack propagation. The method records total measurement of crack propagation, and can be used without visual accessibility, being suitable for special environments like high temperature, high pressure and sour service. Due to the discontinuity represented by the presence of a crack, when electric current flows through the component the crack size can be measured indirectly by the change of the electrical field. The potential difference can be related to crack size through experimental, analytical or numerical calibration curves. Analytical solutions are only limited to a small number of simpler geometries and homogeneous material. For clad and lined pipe, the clad/liner is stainless steel or nickel base alloys but the base pipe is carbon steel. The conductivities of the different materials are different. For lined pipe a small gap exists between liner and base pipe, this may change the electrical field around the root of girth weld. In this paper, finite element analyses are performed to generate the numerical calibration curves for the fatigue crack growth rate testing in sour service environment for clad and lined pipe girth welds. The method developed and described in this paper measures the fatigue crack growth rate for the crack located at the weld root which is in direct contact with the operating environment.
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Kobets, K. R., Sergey Valeryevich Andreev, Alexander Evgenyevich Bondarev, and A. V. Bondarenko. "Application of Volumetric Stereoanimation in Maxillofacial Surgery." In 32nd International Conference on Computer Graphics and Vision. Keldysh Institute of Applied Mathematics, 2022. http://dx.doi.org/10.20948/graphicon-2022-324-329.
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The work is devoted to the application of previously developed algorithms and methods of stereo imaging in the field of maxillofacial surgery. Construction of stereo images can be useful for solving the problem of visual aids in medicine. The work is based on the developed algorithms and software tools for presenting 3D objects in stereo mode on modern autostereoscopic monitors. Test examples of 3D volumetric animations of the results of real CT scans of patients are constructed and presented as illustrations. A similar approach can be used for virtual volumetric 3D visualization of human organs in various fields of medicine. Practical cooperation of medical workers and developers of methods of stereo animation on autostereoscopic monitors on example of practical tasks allows to develop new approaches, necessary for specialists. For medical workers creation of stereopresentation base helps to identify patients' pathologies, to establish communication with the patient by means of visual volumetric representations, to establish communication between medical specialists. The dissemination of such stereoscopic images in various fields is extremely important. Such visual representations help to move the processes of patient analysis, data processing to a new, higher level.
Reports on the topic "Visual field base (VFL)"
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Roesler, Jeffery, Roberto Montemayor, John DeSantis, and Prakhar Gupta. Evaluation of Premature Cracking in Urban Concrete Pavement. Illinois Center for Transportation, January 2021. http://dx.doi.org/10.36501/0197-9191/21-001.
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This study investigated the causes for premature, transverse cracking on urban jointed plain concrete pavements in Illinois. A field survey of 67 sections throughout Illinois coupled with ultrasonic evaluation was completed to synthesize the extent of premature cracking on urban JPCP. The visual survey showed some transverse and longitudinal cracks were a result of improper slab geometry (excessive slab length and width). Ultrasonic tests over the contraction joints determined some notched joints had not activated and adjacent transverse cracks were likely formed as a result. Three-dimensional finite-element analyses confirmed that cracking would not develop as a result of normal environmental factors and slab-base frictional restraint. The concrete mixture also did not appear to be a contributing factor to the premature cracks. Finally, the lack of lubrication on dowel bars was determined to potentially be a primary mechanism that could restrain the transverse contraction joints, produce excessive tensile stresses in the slab, and cause premature transverse cracks to develop.