WorldWideScience

Sample records for surgery computer simulations

  1. Lung surgery assisted by multidetector-row computed tomographic simulation

    International Nuclear Information System (INIS)

    Oizumi, Hiroyuki; Endoh, Makoto; Ota, Hiroshi; Takeda, Shinichi; Suzuki, Jun; Fukaya, Ken; Chiba, Masato; Sadahiro, Mitsuaki

    2009-01-01

    We describe the benefits of lung resection simulation using multidetector computed tomography (MDCT). Since 2004, the 1.0-mm slice digital imaging and communications in medicine (DICOM) server has been used for storing data obtained using 64-row MDCT. We observed that an abnormality could not be visualized from the pleural surface in 10 nodules of 18 lesions undergoing wedge lung resection. These 10 nodules were resected through simulation using a three-dimensional (3D) volume-rendering method by considering parameters such as the position, depth, or distance from the interlobar abnormalities, etc., without the need for any marking methods. For lung lobectomy, identification of the branching structures, diameter, and length of the arteries is useful in selecting the procedure for blood vessel treatment. However, in the initial 10 patients of this series, the preoperative identification of 2 small arterial branches was unsuccessful when this method was used. Therefore, it is important to carefully examine the original data in all 3 views, id est (i.e.), axial, sagittal, and coronal views. The visualization of venous branches in affected segments and intersegmental veins has facilitated the preoperative determination of the anatomical intersegmental plane. We divided the cases of thoracoscopic lung segmentectomy into 3 groups (level 1: simple, level 2: intermediate, and level 3: complex) on the basis of the technical complexity. Only level 1 segmentectomies were performed without MDCT simulation. Further, level 2 and 3 segmentectomies could be successfully performed because of the introduction of MDCT simulation in 25 of 35 patients. Thus, this simulation technique may be useful during a thoracoscopic procedure for lung surgery. (author)

  2. Computer Simulation and Digital Resources for Plastic Surgery Psychomotor Education.

    Science.gov (United States)

    Diaz-Siso, J Rodrigo; Plana, Natalie M; Stranix, John T; Cutting, Court B; McCarthy, Joseph G; Flores, Roberto L

    2016-10-01

    Contemporary plastic surgery residents are increasingly challenged to learn a greater number of complex surgical techniques within a limited period. Surgical simulation and digital education resources have the potential to address some limitations of the traditional training model, and have been shown to accelerate knowledge and skills acquisition. Although animal, cadaver, and bench models are widely used for skills and procedure-specific training, digital simulation has not been fully embraced within plastic surgery. Digital educational resources may play a future role in a multistage strategy for skills and procedures training. The authors present two virtual surgical simulators addressing procedural cognition for cleft repair and craniofacial surgery. Furthermore, the authors describe how partnerships among surgical educators, industry, and philanthropy can be a successful strategy for the development and maintenance of digital simulators and educational resources relevant to plastic surgery training. It is our responsibility as surgical educators not only to create these resources, but to demonstrate their utility for enhanced trainee knowledge and technical skills development. Currently available digital resources should be evaluated in partnership with plastic surgery educational societies to guide trainees and practitioners toward effective digital content.

  3. [Possibilities of computer graphics simulation in orthopedic surgery].

    Science.gov (United States)

    Kessler, P; Wiltfang, J; Teschner, M; Girod, B; Neukam, F W

    2000-11-01

    In addition to standard X-rays, photographic documentation, cephalometric and model analysis, a computer-aided, three-dimensional (3D) simulation system has been developed in close cooperation with the Institute of Communications of the Friedrich-Alexander-Universität Erlangen-Nürnberg. With this simulation system a photorealistic prediction of the expected soft tissue changes can be made. Prerequisites are a 3D reconstruction of the facial skeleton and a 3D laser scan of the face. After data reduction, the two data sets can be matched. Cutting planes enable the transposition of bony segments. The laser scan of the facial surface is combined with the underlying bone via a five-layered soft tissue model to convert bone movements on the soft tissue cover realistically. Further research is necessary to replace the virtual subcutaneous soft tissue model by correct, topographic tissue anatomy.

  4. Computer simulation of orthognathic surgery with video imaging

    Science.gov (United States)

    Sader, Robert; Zeilhofer, Hans-Florian U.; Horch, Hans-Henning

    1994-04-01

    Patients with extreme jaw imbalance must often undergo operative corrections. The goal of therapy is to harmonize the stomatognathic system and an aesthetical correction of the face profile. A new procedure will be presented which supports the maxillo-facial surgeon in planning the operation and which also presents the patient the result of the treatment by video images. Once an x-ray has been digitized it is possible to produce individualized cephalometric analyses. Using a ceph on screen, all current orthognathic operations can be simulated, whereby the bony segments are moved according to given parameters, and a new soft tissue profile can be calculated. The profile of the patient is fed into the computer by way of a video system and correlated to the ceph. Using the simulated operation the computer calculates a new video image of the patient which presents the expected postoperative appearance. In studies of patients treated between 1987-91, 76 out of 121 patients were able to be evaluated. The deviation in profile change varied between .0 and 1.6mm. A side effect of the practical applications was an increase in patient compliance.

  5. Interactive virtual simulation using a 3D computer graphics model for microvascular decompression surgery.

    Science.gov (United States)

    Oishi, Makoto; Fukuda, Masafumi; Hiraishi, Tetsuya; Yajima, Naoki; Sato, Yosuke; Fujii, Yukihiko

    2012-09-01

    The purpose of this paper is to report on the authors' advanced presurgical interactive virtual simulation technique using a 3D computer graphics model for microvascular decompression (MVD) surgery. The authors performed interactive virtual simulation prior to surgery in 26 patients with trigeminal neuralgia or hemifacial spasm. The 3D computer graphics models for interactive virtual simulation were composed of the brainstem, cerebellum, cranial nerves, vessels, and skull individually created by the image analysis, including segmentation, surface rendering, and data fusion for data collected by 3-T MRI and 64-row multidetector CT systems. Interactive virtual simulation was performed by employing novel computer-aided design software with manipulation of a haptic device to imitate the surgical procedures of bone drilling and retraction of the cerebellum. The findings were compared with intraoperative findings. In all patients, interactive virtual simulation provided detailed and realistic surgical perspectives, of sufficient quality, representing the lateral suboccipital route. The causes of trigeminal neuralgia or hemifacial spasm determined by observing 3D computer graphics models were concordant with those identified intraoperatively in 25 (96%) of 26 patients, which was a significantly higher rate than the 73% concordance rate (concordance in 19 of 26 patients) obtained by review of 2D images only (p computer graphics model provided a realistic environment for performing virtual simulations prior to MVD surgery and enabled us to ascertain complex microsurgical anatomy.

  6. A review of computer-aided oral and maxillofacial surgery: planning, simulation and navigation.

    Science.gov (United States)

    Chen, Xiaojun; Xu, Lu; Sun, Yi; Politis, Constantinus

    2016-11-01

    Currently, oral and maxillofacial surgery (OMFS) still poses a significant challenge for surgeons due to the anatomic complexity and limited field of view of the oral cavity. With the great development of computer technologies, he computer-aided surgery has been widely used for minimizing the risks and improving the precision of surgery. Areas covered: The major goal of this paper is to provide a comprehensive reference source of current and future development of computer-aided OMFS including surgical planning, simulation and navigation for relevant researchers. Expert commentary: Compared with the traditional OMFS, computer-aided OMFS overcomes the disadvantage that the treatment on the region of anatomically complex maxillofacial depends almost exclusively on the experience of the surgeon.

  7. Clinical application of 3D computer simulation for upper limb surgery

    International Nuclear Information System (INIS)

    Murase, Tsuyoshi; Moritomo, Hisao; Oka, Kunihiro; Arimitsu, Sayuri; Shimada, Kozo

    2008-01-01

    To perform precise orthopaedic surgery, we have been developing a surgical method using a custom-made surgical device designed based on preoperative three-dimensional computer simulation. The purpose of this study was to investigate the preliminary results of its clinical application for corrective osteotomy of the upper extremity. Twenty patients with long bone deformities of the upper extremities (four cubitus varus deformities, nine malunited forearm fractures, six malunited distal radial fractures and one congenital deformity of the forearm) participated in this study. Three-dimensional computer models of the affected bone and the contralateral normal bone were constructed from computed tomography data. By comparing these models, the three-dimensional deformity axis and the accurate amount of deformity around it were quantified. Three-dimensional deformity correction was then simulated. A custom-made osteotomy template was designed and manufactured as a real plastic model aiming to reproduce the preoperative simulation in the actual operation. In the operation, we put the template on the bone surface, cut the bone through a slit on the template, and corrected the deformity as preoperatively simulated, followed by internal fixation. Radiographic and clinical evaluations were made in all cases before surgery and at the most recent follow-up. Corrective osteotomy was achieved as simulated in all cases. All patients had bone fusion within six months. Regarding the cubitus varus deformity, the average carrying angle and tilting angle were 5deg and 28deg after surgery. For malunited forearm fractures, angular deformities on radiographs were nearly nonexistent after surgery. All radiographic parameters in malunited distal radius fractures were normalized. The range of forearm rotation in cases of forearm malunion and that of wrist flexion-extension in cases of malunited distal radius improved after surgery. (author)

  8. Computer Simulation Surgery for Mandibular Reconstruction Using a Fibular Osteotomy Guide

    Directory of Open Access Journals (Sweden)

    Woo Shik Jeong

    2014-09-01

    Full Text Available In the present study, a fibular osteotomy guide based on a computer simulation was applied to a patient who had undergone mandibular segmental ostectomy due to oncological complications. This patient was a 68-year-old woman who presented to our department with a biopsy-proven squamous cell carcinoma on her left gingival area. This lesion had destroyed the cortical bony structure, and the patient showed attenuation of her soft tissue along the inferior alveolar nerve, indicating perineural spread of the tumor. Prior to surgery, a three-dimensional computed tomography scan of the facial and fibular bones was performed. We then created a virtual computer simulation of the mandibular segmental defect through which we segmented the fibular to reconstruct the proper angulation in the original mandible. Approximately 2-cm segments were created on the basis of this simulation and applied to the virtually simulated mandibular segmental defect. Thus, we obtained a virtual model of the ideal mandibular reconstruction for this patient with a fibular free flap. We could then use this computer simulation for the subsequent surgery and minimize the bony gaps between the multiple fibular bony segments.

  9. Comparison of real and computer-simulated outcomes of LASIK refractive surgery

    Science.gov (United States)

    Cano, Daniel; Barbero, Sergio; Marcos, Susana

    2004-06-01

    Computer simulations of alternative LASIK ablation patterns were performed for corneal elevation maps of 13 real myopic corneas (range of myopia, -2.0 to -11.5 D). The computationally simulated ablation patterns were designed with biconic surfaces (standard Munnerlyn pattern, parabolic pattern, and biconic pattern) or with aberrometry measurements (customized pattern). Simulated results were compared with real postoperative outcomes. Standard LASIK refractive surgery for myopia increased corneal asphericity and spherical aberration. Computations with the theoretical Munnerlyn ablation pattern did not increase the corneal asphericity and spherical aberration. The theoretical parabolic pattern induced a slight increase of asphericity and spherical aberration, explaining only 40% of the clinically found increase. The theoretical biconic pattern controlled corneal spherical aberration. Computations showed that the theoretical customized pattern can correct high-order asymmetric aberrations. Simulations of changes in efficiency due to reflection and nonnormal incidence of the laser light showed a further increase in corneal asphericity. Consideration of these effects with a parabolic pattern accounts for 70% of the clinical increase in asphericity.

  10. Recent advances in 3D computed tomography techniques for simulation and navigation in hepatobiliary pancreatic surgery.

    Science.gov (United States)

    Uchida, Masafumi

    2014-04-01

    A few years ago it could take several hours to complete a 3D image using a 3D workstation. Thanks to advances in computer science, obtaining results of interest now requires only a few minutes. Many recent 3D workstations or multimedia computers are equipped with onboard 3D virtual patient modeling software, which enables patient-specific preoperative assessment and virtual planning, navigation, and tool positioning. Although medical 3D imaging can now be conducted using various modalities, including computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET), and ultrasonography (US) among others, the highest quality images are obtained using CT data, and CT images are now the most commonly used source of data for 3D simulation and navigation image. If the 2D source image is bad, no amount of 3D image manipulation in software will provide a quality 3D image. In this exhibition, the recent advances in CT imaging technique and 3D visualization of the hepatobiliary and pancreatic abnormalities are featured, including scan and image reconstruction technique, contrast-enhanced techniques, new application of advanced CT scan techniques, and new virtual reality simulation and navigation imaging. © 2014 Japanese Society of Hepato-Biliary-Pancreatic Surgery.

  11. Does computer-aided surgical simulation improve efficiency in bimaxillary orthognathic surgery?

    Science.gov (United States)

    Schwartz, H C

    2014-05-01

    The purpose of this study was to compare the efficiency of bimaxillary orthognathic surgery using computer-aided surgical simulation (CASS), with cases planned using traditional methods. Total doctor time was used to measure efficiency. While costs vary widely in different localities and in different health schemes, time is a valuable and limited resource everywhere. For this reason, total doctor time is a more useful measure of efficiency than is cost. Even though we use CASS primarily for planning more complex cases at the present time, this study showed an average saving of 60min for each case. In the context of a department that performs 200 bimaxillary cases each year, this would represent a saving of 25 days of doctor time, if applied to every case. It is concluded that CASS offers great potential for improving efficiency when used in the planning of bimaxillary orthognathic surgery. It saves significant doctor time that can be applied to additional surgical work. Copyright © 2013 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  12. Three dimensional computed tomography lung modeling is useful in simulation and navigation of lung cancer surgery.

    Science.gov (United States)

    Ikeda, Norihiko; Yoshimura, Akinobu; Hagiwara, Masaru; Akata, Soichi; Saji, Hisashi

    2013-01-01

    The number of minimally invasive operations, such as video-assisted thoracoscopic surgery (VATS) lobectomy or segmentectomy, has enormously increased in recent years. These operations require extreme knowledge of the anatomy of pulmonary vessels and bronchi in each patient, and surgeons must carefully dissect the branches of pulmonary vessels during operation. Thus, foreknowledge of the anatomy of each patient would greatly contribute to the safety and accuracy of the operation. The development of multi-detector computed tomography (MDCT) has promoted three dimensional (3D) images of lung structures. It is possible to see the vascular and bronchial structures from the view of the operator; therefore, it is employed for preoperative simulation as well as navigation during operation. Due to advances in software, even small vessels can be accurately imaged, which is useful in performing segmentectomy. Surgical simulation and navigation systems based on high quality 3D lung modeling, including vascular and bronchial structures, can be used routinely to enhance the safety operation, education of junior staff, as well as providing a greater sense of security to the operators.

  13. COMPUTERS IN SURGERY

    African Journals Online (AJOL)

    BODE

    Key words: Computers, surgery, applications. Introduction ... With improved memory, speed and processing power in an ever more compact ... with picture and voice embedment to wit. With the ... recall the tedium of anatomy, physiology and.

  14. Protocol for concomitant temporomandibular joint custom-fitted total joint reconstruction and orthognathic surgery utilizing computer-assisted surgical simulation.

    Science.gov (United States)

    Movahed, Reza; Teschke, Marcus; Wolford, Larry M

    2013-12-01

    Clinicians who address temporomandibular joint (TMJ) pathology and dentofacial deformities surgically can perform the surgery in 1 stage or 2 separate stages. The 2-stage approach requires the patient to undergo 2 separate operations and anesthesia, significantly prolonging the overall treatment. However, performing concomitant TMJ and orthognathic surgery (CTOS) in these cases requires careful treatment planning and surgical proficiency in the 2 surgical areas. This article presents a new treatment protocol for the application of computer-assisted surgical simulation in CTOS cases requiring reconstruction with patient-fitted total joint prostheses. The traditional and new CTOS protocols are described and compared. The new CTOS protocol helps decrease the preoperative workup time and increase the accuracy of model surgery. Copyright © 2013 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  15. Computer-assisted preoperative simulation for positioning and fixation of plate in 2-stage procedure combining maxillary advancement by distraction technique and mandibular setback surgery

    Directory of Open Access Journals (Sweden)

    Hideyuki Suenaga

    2016-01-01

    Conclusion: The implementation of the computer-assisted preoperative simulation for the positioning and fixation of plate in 2-stage orthognathic procedure using distraction technique and mandibular setback surgery yielded good results.

  16. [Simulation in pediatric surgery].

    Science.gov (United States)

    Becmeur, François; Lacreuse, Isabelle; Soler, Luc

    2011-11-01

    Simulation in paediatric surgery is essential for educational, ethical, medicolegal and economic reasons, and is particularly important for rare procedures. There are three different levels of simulation:--simulation of basic techniques in order to learn or improve surgical skills (dissection, intracorporeal knots, etc.);--preparation for surgery using virtual reality, to perfect and test various procedures on a virtual patient, and to determine the best approaches for individual cases;--behavioral simulation underlines the importance of the preoperative check-list and facilitates crisis management (complications, conversion, etc.).

  17. Three-Dimensional Liver Surgery Simulation: Computer-Assisted Surgical Planning with Three-Dimensional Simulation Software and Three-Dimensional Printing.

    Science.gov (United States)

    Oshiro, Yukio; Ohkohchi, Nobuhiro

    2017-06-01

    To perform accurate hepatectomy without injury, it is necessary to understand the anatomical relationship among the branches of Glisson's sheath, hepatic veins, and tumor. In Japan, three-dimensional (3D) preoperative simulation for liver surgery is becoming increasingly common, and liver 3D modeling and 3D hepatectomy simulation by 3D analysis software for liver surgery have been covered by universal healthcare insurance since 2012. Herein, we review the history of virtual hepatectomy using computer-assisted surgery (CAS) and our research to date, and we discuss the future prospects of CAS. We have used the SYNAPSE VINCENT medical imaging system (Fujifilm Medical, Tokyo, Japan) for 3D visualization and virtual resection of the liver since 2010. We developed a novel fusion imaging technique combining 3D computed tomography (CT) with magnetic resonance imaging (MRI). The fusion image enables us to easily visualize anatomic relationships among the hepatic arteries, portal veins, bile duct, and tumor in the hepatic hilum. In 2013, we developed an original software, called Liversim, which enables real-time deformation of the liver using physical simulation, and a randomized control trial has recently been conducted to evaluate the use of Liversim and SYNAPSE VINCENT for preoperative simulation and planning. Furthermore, we developed a novel hollow 3D-printed liver model whose surface is covered with frames. This model is useful for safe liver resection, has better visibility, and the production cost is reduced to one-third of a previous model. Preoperative simulation and navigation with CAS in liver resection are expected to help planning and conducting a surgery and surgical education. Thus, a novel CAS system will contribute to not only the performance of reliable hepatectomy but also to surgical education.

  18. Computer assisted radiology and surgery. CARS 2010

    International Nuclear Information System (INIS)

    Anon.

    2010-01-01

    The conference proceedings include contributions to the following topics: (1) CARS Clinical Day: minimally invasive spiral surgery, interventional radiology; (2) CARS - computer assisted radiology and surgery: ophthalmology, stimulation methods, new approaches to diagnosis and therapy; (3) Computer assisted radiology 24th International congress and exhibition: computer tomography and magnetic resonance, digital angiographic imaging, digital radiography, ultrasound, computer assisted radiation therapy, medical workstations, image processing and display; (4) 14th Annual conference of the International Society for computer aided surgery; ENT-CMF head and neck surgery computer-assisted neurosurgery, cardiovascular surgery, image guided liver surgery, abdominal and laparoscopic surgery, computer-assisted orthopedic surgery, image processing and visualization, surgical robotics and instrumentation, surgical modeling, simulation and education; (5) 28th International EuroPACS meeting: image distribution and integration strategies, planning and evaluation, telemedicine and standards, workflow and data flow in radiology; (6) 11th CARS/SPIE/EuroPACS joint workshop on surgical PACS and the digital operating, management and assessment of OR systems and integration; (7) 12th International workshop on computer-aided diagnosis: special session on breast CAD, special session on thoracic CAD, special session on abdominal brain, lumbar spine CAD; (8) 16th computed Maxillofacial imaging congress: computed maxillofacial imaging in dental implantology, orthodontics and dentofacial orthopedics; approaches to 3D maxillofacial imaging; surgical navigation; (9) 2nd EuroNOTES/CARS workshop on NOTES: an interdisciplinary challenge; (10) 2nd EPMA/CARS workshop on personalized medicine and ICT.; (11)poster sessions.

  19. Computer assisted radiology and surgery. CARS 2010

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2010-06-15

    The conference proceedings include contributions to the following topics: (1) CARS Clinical Day: minimally invasive spiral surgery, interventional radiology; (2) CARS - computer assisted radiology and surgery: ophthalmology, stimulation methods, new approaches to diagnosis and therapy; (3) Computer assisted radiology 24th International congress and exhibition: computer tomography and magnetic resonance, digital angiographic imaging, digital radiography, ultrasound, computer assisted radiation therapy, medical workstations, image processing and display; (4) 14th Annual conference of the International Society for computer aided surgery; ENT-CMF head and neck surgery computer-assisted neurosurgery, cardiovascular surgery, image guided liver surgery, abdominal and laparoscopic surgery, computer-assisted orthopedic surgery, image processing and visualization, surgical robotics and instrumentation, surgical modeling, simulation and education; (5) 28th International EuroPACS meeting: image distribution and integration strategies, planning and evaluation, telemedicine and standards, workflow and data flow in radiology; (6) 11th CARS/SPIE/EuroPACS joint workshop on surgical PACS and the digital operating, management and assessment of OR systems and integration; (7) 12th International workshop on computer-aided diagnosis: special session on breast CAD, special session on thoracic CAD, special session on abdominal brain, lumbar spine CAD; (8) 16th computed Maxillofacial imaging congress: computed maxillofacial imaging in dental implantology, orthodontics and dentofacial orthopedics; approaches to 3D maxillofacial imaging; surgical navigation; (9) 2nd EuroNOTES/CARS workshop on NOTES: an interdisciplinary challenge; (10) 2nd EPMA/CARS workshop on personalized medicine and ICT.; (11)poster sessions.

  20. Accuracy of a Computer-Aided Surgical Simulation (CASS) Protocol for Orthognathic Surgery: A Prospective Multicenter Study

    Science.gov (United States)

    Hsu, Sam Sheng-Pin; Gateno, Jaime; Bell, R. Bryan; Hirsch, David L.; Markiewicz, Michael R.; Teichgraeber, John F.; Zhou, Xiaobo; Xia, James J.

    2012-01-01

    Purpose The purpose of this prospective multicenter study was to assess the accuracy of a computer-aided surgical simulation (CASS) protocol for orthognathic surgery. Materials and Methods The accuracy of the CASS protocol was assessed by comparing planned and postoperative outcomes of 65 consecutive patients enrolled from 3 centers. Computer-generated surgical splints were used for all patients. For the genioplasty, one center utilized computer-generated chin templates to reposition the chin segment only for patients with asymmetry. Standard intraoperative measurements were utilized without the chin templates for the remaining patients. The primary outcome measurements were linear and angular differences for the maxilla, mandible and chin when the planned and postoperative models were registered at the cranium. The secondary outcome measurements were: maxillary dental midline difference between the planned and postoperative positions; and linear and angular differences of the chin segment between the groups with and without the use of the template. The latter was measured when the planned and postoperative models were registered at mandibular body. Statistical analyses were performed, and the accuracy was reported using root mean square deviation (RMSD) and Bland and Altman's method for assessing measurement agreement. Results In the primary outcome measurements, there was no statistically significant difference among the 3 centers for the maxilla and mandible. The largest RMSD was 1.0mm and 1.5° for the maxilla, and 1.1mm and 1.8° for the mandible. For the chin, there was a statistically significant difference between the groups with and without the use of the chin template. The chin template group showed excellent accuracy with largest positional RMSD of 1.0mm and the largest orientational RSMD of 2.2°. However, larger variances were observed in the group not using the chin template. This was significant in anteroposterior and superoinferior directions, as in

  1. Computer-assisted preoperative simulation for positioning and fixation of plate in 2-stage procedure combining maxillary advancement by distraction technique and mandibular setback surgery.

    Science.gov (United States)

    Suenaga, Hideyuki; Taniguchi, Asako; Yonenaga, Kazumichi; Hoshi, Kazuto; Takato, Tsuyoshi

    2016-01-01

    Computer-assisted preoperative simulation surgery is employed to plan and interact with the 3D images during the orthognathic procedure. It is useful for positioning and fixation of maxilla by a plate. We report a case of maxillary retrusion by a bilateral cleft lip and palate, in which a 2-stage orthognathic procedure (maxillary advancement by distraction technique and mandibular setback surgery) was performed following a computer-assisted preoperative simulation planning to achieve the positioning and fixation of the plate. A high accuracy was achieved in the present case. A 21-year-old male patient presented to our department with a complaint of maxillary retrusion following bilateral cleft lip and palate. Computer-assisted preoperative simulation with 2-stage orthognathic procedure using distraction technique and mandibular setback surgery was planned. The preoperative planning of the procedure resulted in good aesthetic outcomes. The error of the maxillary position was less than 1mm. The implementation of the computer-assisted preoperative simulation for the positioning and fixation of plate in 2-stage orthognathic procedure using distraction technique and mandibular setback surgery yielded good results. Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  2. Computational surgery and dual training computing, robotics and imaging

    CERN Document Server

    Bass, Barbara; Berceli, Scott; Collet, Christophe; Cerveri, Pietro

    2014-01-01

    This critical volume focuses on the use of medical imaging, medical robotics, simulation, and information technology in surgery. It offers a road map for computational surgery success,  discusses the computer-assisted management of disease and surgery, and provides a rational for image processing and diagnostic. This book also presents some advances on image-driven intervention and robotics, as well as evaluates models and simulations for a broad spectrum of cancers as well as cardiovascular, neurological, and bone diseases. Training and performance analysis in surgery assisted by robotic systems is also covered. This book also: ·         Provides a comprehensive overview of the use of computational surgery and disease management ·         Discusses the design and use of medical robotic tools for orthopedic surgery, endoscopic surgery, and prostate surgery ·         Provides practical examples and case studies in the areas of image processing, virtual surgery, and simulation traini...

  3. Computer-assisted surgery simulations and directed practice of total knee arthroplasty: educational benefits to the trainee.

    Science.gov (United States)

    Myden, C A; Anglin, C; Kopp, G D; Hutchison, C R

    2012-01-01

    Orthopaedic residents typically learn to perform total knee arthroplasty (TKA) through an apprenticeship-type model, which is a necessarily slow process. Surgical skills courses, using artificial bones, have been shown to improve technical and cognitive skills significantly within a couple of days. The addition of computer-assisted surgery (CAS) simulations challenges the participants to consider the same task in a different context, promoting cognitive flexibility. We designed a hands-on educational intervention for junior residents with a conventional tibiofemoral TKA station, two different tibiofemoral CAS stations, and a CAS and conventional patellar resection station, including both qualitative and quantitative analyses. Qualitatively, structured interviews before and after the course were analyzed for recurring themes. Quantitatively, subjects were evaluated on their technical skills before and after the course, and on a multiple-choice knowledge test and error detection test after the course, in comparison to senior residents who performed only the testing. Four themes emerged: confidence, awareness, deepening knowledge and changed perspectives. The residents' attitudes to CAS changed from negative before the course to neutral or positive afterwards. The junior resident group completed 23% of tasks in the pre-course skills test and 75% of tasks on the post-test (peducational interventions, promoting cognitive flexibility, would benefit trainees, attending surgeons, the healthcare system and patients.

  4. Computational Modeling in Liver Surgery

    Directory of Open Access Journals (Sweden)

    Bruno Christ

    2017-11-01

    Full Text Available The need for extended liver resection is increasing due to the growing incidence of liver tumors in aging societies. Individualized surgical planning is the key for identifying the optimal resection strategy and to minimize the risk of postoperative liver failure and tumor recurrence. Current computational tools provide virtual planning of liver resection by taking into account the spatial relationship between the tumor and the hepatic vascular trees, as well as the size of the future liver remnant. However, size and function of the liver are not necessarily equivalent. Hence, determining the future liver volume might misestimate the future liver function, especially in cases of hepatic comorbidities such as hepatic steatosis. A systems medicine approach could be applied, including biological, medical, and surgical aspects, by integrating all available anatomical and functional information of the individual patient. Such an approach holds promise for better prediction of postoperative liver function and hence improved risk assessment. This review provides an overview of mathematical models related to the liver and its function and explores their potential relevance for computational liver surgery. We first summarize key facts of hepatic anatomy, physiology, and pathology relevant for hepatic surgery, followed by a description of the computational tools currently used in liver surgical planning. Then we present selected state-of-the-art computational liver models potentially useful to support liver surgery. Finally, we discuss the main challenges that will need to be addressed when developing advanced computational planning tools in the context of liver surgery.

  5. CUDA-based real time surgery simulation.

    Science.gov (United States)

    Liu, Youquan; De, Suvranu

    2008-01-01

    In this paper we present a general software platform that enables real time surgery simulation on the newly available compute unified device architecture (CUDA)from NVIDIA. CUDA-enabled GPUs harness the power of 128 processors which allow data parallel computations. Compared to the previous GPGPU, it is significantly more flexible with a C language interface. We report implementation of both collision detection and consequent deformation computation algorithms. Our test results indicate that the CUDA enables a twenty times speedup for collision detection and about fifteen times speedup for deformation computation on an Intel Core 2 Quad 2.66 GHz machine with GeForce 8800 GTX.

  6. Algorithm for planning a double-jaw orthognathic surgery using a computer-aided surgical simulation (CASS) protocol. Part 1: planning sequence

    Science.gov (United States)

    Xia, J. J.; Gateno, J.; Teichgraeber, J. F.; Yuan, P.; Chen, K.-C.; Li, J.; Zhang, X.; Tang, Z.; Alfi, D. M.

    2015-01-01

    The success of craniomaxillofacial (CMF) surgery depends not only on the surgical techniques, but also on an accurate surgical plan. The adoption of computer-aided surgical simulation (CASS) has created a paradigm shift in surgical planning. However, planning an orthognathic operation using CASS differs fundamentally from planning using traditional methods. With this in mind, the Surgical Planning Laboratory of Houston Methodist Research Institute has developed a CASS protocol designed specifically for orthognathic surgery. The purpose of this article is to present an algorithm using virtual tools for planning a double-jaw orthognathic operation. This paper will serve as an operation manual for surgeons wanting to incorporate CASS into their clinical practice. PMID:26573562

  7. Simulation in shoulder surgery.

    Science.gov (United States)

    Colaço, Henry B; Tennent, Duncan

    2016-10-01

    Simulation is a rapidly developing field in medical education. There is a growing need for trainee surgeons to acquire surgical skills in a cost-effective learning environment to improve patient safety and compensate for a reduction in training time and operative experience. Although simulation is not a replacement for traditional models of surgical training, and robust assessment metrics need to be validated before widespread use for accreditation, it is a useful adjunct that may ultimately lead to improving surgical outcomes for our patients.

  8. A Tissue Relevance and Meshing Method for Computing Patient-Specific Anatomical Models in Endoscopic Sinus Surgery Simulation

    Science.gov (United States)

    Audette, M. A.; Hertel, I.; Burgert, O.; Strauss, G.

    This paper presents on-going work on a method for determining which subvolumes of a patient-specific tissue map, extracted from CT data of the head, are relevant to simulating endoscopic sinus surgery of that individual, and for decomposing these relevant tissues into triangles and tetrahedra whose mesh size is well controlled. The overall goal is to limit the complexity of the real-time biomechanical interaction while ensuring the clinical relevance of the simulation. Relevant tissues are determined as the union of the pathology present in the patient, of critical tissues deemed to be near the intended surgical path or pathology, and of bone and soft tissue near the intended path, pathology or critical tissues. The processing of tissues, prior to meshing, is based on the Fast Marching method applied under various guises, in a conditional manner that is related to tissue classes. The meshing is based on an adaptation of a meshing method of ours, which combines the Marching Tetrahedra method and the discrete Simplex mesh surface model to produce a topologically faithful surface mesh with well controlled edge and face size as a first stage, and Almost-regular Tetrahedralization of the same prescribed mesh size as a last stage.

  9. Computer-assisted oral and maxillofacial surgery

    International Nuclear Information System (INIS)

    Hassfeld, S.; Brief, J.; Muehling, J.; Krempien, R.; Mende, U.; Raczkowsky, J.; Muenchenberg, J.; Woern, H.; Giess, H.; Meinzer, H.P.

    2000-01-01

    Background: Methods from the area of virtual reality are used in oral and maxillofacial surgery for the planning and three-dimensional individual simulation of surgeries. Simulation: In order to simulate complex surgeries with the aid of a computer, the diagnostic image data and especially various imaging modalities (CT, MRT, US) must be arranged in relation to each other, thus enabling rapid switching between the various modalities as well as the viewing of mixed images. Segmenting techniques for the reconstruction of three-dimensional representations of soft-tissue and osseous areas are required. We must develop ergonomic and intuitively useable interaction methods for the surgeon, thus allowing for precise and fast entry of the planned surgical intervention in the planning and simulation phase. Surgery: During the surgical phase, instrument navigation tools offer the surgeon interactive support through operation guidance and control of potential dangers. This feature is already available today. Future intraoperative assistance will take the form of such passive tools for the support of intraoperative orientation as well as so-called tracking systems (semi-active systems) which accompany and support the surgeons' work. The final form are robots which execute specific steps completely autonomously. Discussion: The techniques of virtual reality keep gaining in importance for medical applications. Many applications are still being developed or are still in the form of a prototype. However, it is already clear that developments in this area will have a considerable effect on the surgeon's routine work. (orig.) [de

  10. Quantitative computed tomography for the prediction of pulmonary function after lung cancer surgery: a simple method using simulation software.

    Science.gov (United States)

    Ueda, Kazuhiro; Tanaka, Toshiki; Li, Tao-Sheng; Tanaka, Nobuyuki; Hamano, Kimikazu

    2009-03-01

    The prediction of pulmonary functional reserve is mandatory in therapeutic decision-making for patients with resectable lung cancer, especially those with underlying lung disease. Volumetric analysis in combination with densitometric analysis of the affected lung lobe or segment with quantitative computed tomography (CT) helps to identify residual pulmonary function, although the utility of this modality needs investigation. The subjects of this prospective study were 30 patients with resectable lung cancer. A three-dimensional CT lung model was created with voxels representing normal lung attenuation (-600 to -910 Hounsfield units). Residual pulmonary function was predicted by drawing a boundary line between the lung to be preserved and that to be resected, directly on the lung model. The predicted values were correlated with the postoperative measured values. The predicted and measured values corresponded well (r=0.89, plung cancer surgery and helped to identify patients whose functional reserves are likely to be underestimated. Hence, this modality should be utilized for patients with marginal pulmonary function.

  11. Scientific computer simulation review

    International Nuclear Information System (INIS)

    Kaizer, Joshua S.; Heller, A. Kevin; Oberkampf, William L.

    2015-01-01

    Before the results of a scientific computer simulation are used for any purpose, it should be determined if those results can be trusted. Answering that question of trust is the domain of scientific computer simulation review. There is limited literature that focuses on simulation review, and most is specific to the review of a particular type of simulation. This work is intended to provide a foundation for a common understanding of simulation review. This is accomplished through three contributions. First, scientific computer simulation review is formally defined. This definition identifies the scope of simulation review and provides the boundaries of the review process. Second, maturity assessment theory is developed. This development clarifies the concepts of maturity criteria, maturity assessment sets, and maturity assessment frameworks, which are essential for performing simulation review. Finally, simulation review is described as the application of a maturity assessment framework. This is illustrated through evaluating a simulation review performed by the U.S. Nuclear Regulatory Commission. In making these contributions, this work provides a means for a more objective assessment of a simulation’s trustworthiness and takes the next step in establishing scientific computer simulation review as its own field. - Highlights: • We define scientific computer simulation review. • We develop maturity assessment theory. • We formally define a maturity assessment framework. • We describe simulation review as the application of a maturity framework. • We provide an example of a simulation review using a maturity framework

  12. CARS 2008: Computer Assisted Radiology and Surgery. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2008-06-15

    The proceedings contain contributions to the following topics: digital imaging, computed tomography, magnetic resonance, cardiac and vascular imaging, computer assisted radiation therapy, image processing and display, minimal invasive spinal surgery, computer assisted treatment of the prostate, the interventional radiology suite of the future, interventional oncology, computer assisted neurosurgery, computer assisted head and neck and ENT surgery, cardiovascular surgery, computer assisted orthopedic surgery, image processing and visualization, surgical robotics, instrumentation and navigation, surgical modelling, simulation and education, endoscopy and related techniques, workflow and new concepts in surgery, research training group 1126: intelligent surgery, digital operating room, image distribution and integration strategies, regional PACS and telemedicine, PACS - beyond radiology and E-learning, workflow and standardization, breast CAD, thoracic CAD, abdominal CAD, brain CAD, orthodontics, dentofacial orthopedics and airways, imaging and treating temporomandibular joint conditions, maxillofacial cone beam CT, craniomaxillofacial image fusion and CBCT incidental findings, image guided craniomaxillofacial procedures, imaging as a biomarker for therapy response, computer aided diagnosis. The Poster sessions cover the topics computer aided surgery, Euro PACS meeting, computer assisted radiology, computer aided diagnosis and computer assisted radiology and surgery.

  13. CARS 2008: Computer Assisted Radiology and Surgery. Proceedings

    International Nuclear Information System (INIS)

    2008-01-01

    The proceedings contain contributions to the following topics: digital imaging, computed tomography, magnetic resonance, cardiac and vascular imaging, computer assisted radiation therapy, image processing and display, minimal invasive spinal surgery, computer assisted treatment of the prostate, the interventional radiology suite of the future, interventional oncology, computer assisted neurosurgery, computer assisted head and neck and ENT surgery, cardiovascular surgery, computer assisted orthopedic surgery, image processing and visualization, surgical robotics, instrumentation and navigation, surgical modelling, simulation and education, endoscopy and related techniques, workflow and new concepts in surgery, research training group 1126: intelligent surgery, digital operating room, image distribution and integration strategies, regional PACS and telemedicine, PACS - beyond radiology and E-learning, workflow and standardization, breast CAD, thoracic CAD, abdominal CAD, brain CAD, orthodontics, dentofacial orthopedics and airways, imaging and treating temporomandibular joint conditions, maxillofacial cone beam CT, craniomaxillofacial image fusion and CBCT incidental findings, image guided craniomaxillofacial procedures, imaging as a biomarker for therapy response, computer aided diagnosis. The Poster sessions cover the topics computer aided surgery, Euro PACS meeting, computer assisted radiology, computer aided diagnosis and computer assisted radiology and surgery

  14. Simulation of quantum computers

    NARCIS (Netherlands)

    De Raedt, H; Michielsen, K; Hams, AH; Miyashita, S; Saito, K; Landau, DP; Lewis, SP; Schuttler, HB

    2001-01-01

    We describe a simulation approach to study the functioning of Quantum Computer hardware. The latter is modeled by a collection of interacting spin-1/2 objects. The time evolution of this spin system maps one-to-one to a quantum program carried out by the Quantum Computer. Our simulation software

  15. Simulation of quantum computers

    NARCIS (Netherlands)

    Raedt, H. De; Michielsen, K.; Hams, A.H.; Miyashita, S.; Saito, K.

    2000-01-01

    We describe a simulation approach to study the functioning of Quantum Computer hardware. The latter is modeled by a collection of interacting spin-1/2 objects. The time evolution of this spin system maps one-to-one to a quantum program carried out by the Quantum Computer. Our simulation software

  16. [Suture simulator - Cleft palate surgery].

    Science.gov (United States)

    Devinck, F; Riot, S; Qassemyar, A; Belkhou, A; Wolber, A; Martinot Duquennoy, V; Guerreschi, P

    2017-04-01

    Cleft palate requires surgery in the first years of life, furthermore repairing anatomically the soft and hard palate is complex on a surgical level because of the fine tissues and the local intraoral configuration. It is valuable to train first on simulators before going to the operating room. However, there is no material dedicated to learning how to perform intraoral sutures in cleft palate surgery. We made one, in an artisanal manner, in order to practice before the real surgical gesture. The simulator was designed based on precise anatomical data. A steel pipe, fixed on a rigid base represented the oral cavity. An adapted split spoon represented the palate. All pieces could be removed in order to apply a hydrocellular dressing before training for sutures. Our simulator was tested by 3 senior surgeons in our department in close to real-life conditions in order to evaluate its anatomical accuracy. It is valuable to have a simulator to train on cleft palate sutures within teaching university hospitals that manage this pathology. Our simulator has a very low cost, it is easy to make and is anatomically accurate. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  17. Parallel reservoir simulator computations

    International Nuclear Information System (INIS)

    Hemanth-Kumar, K.; Young, L.C.

    1995-01-01

    The adaptation of a reservoir simulator for parallel computations is described. The simulator was originally designed for vector processors. It performs approximately 99% of its calculations in vector/parallel mode and relative to scalar calculations it achieves speedups of 65 and 81 for black oil and EOS simulations, respectively on the CRAY C-90

  18. Computed tomography, after abdominal surgery

    Energy Technology Data Exchange (ETDEWEB)

    Vogel, H.; Toedt, H.C.

    1985-09-01

    The CT-examinations of 131 patients were analyzed after abdominal surgery. After nephrectomy, splenectomy, partial hepatectomy and pancreatectomy a displacement of the neighbouring intraabdominal and retroperitoneal organs was seen. Scar-tissue was observed containing fat, which faciltated the differential diagnosis to tumor recurrency. The changes of the roentgenmorphology were not so obvious after gastrointestinal surgery. After vascular surgery the permeability of an anastomosis or an operated artery could be demonstrated by bolus injection. (orig.).

  19. Computed tomography, after abdominal surgery

    International Nuclear Information System (INIS)

    Vogel, H.; Toedt, H.C.; Hamburg Univ.

    1985-01-01

    The CT-examinations of 131 patients were analyzed after abdominal surgery. After nephrectomy, splenectomy, partial hepatectomy and pancreatectomy a displacement of the neighbouring intraabdominal and retroperitoneal organs was seen. Scar-tissue was observed containing fat, which fascilated the differentialdiagnosis to tumorrecurrency. The changes of the roentgenmorphology were not so abvious after gastro-intestinal surgery. After vascular surgery the permeability of an anastomosis or an operated artery could be demonstrated by bolusinjection. (orig.) [de

  20. Computer Modeling and Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Pronskikh, V. S. [Fermilab

    2014-05-09

    Verification and validation of computer codes and models used in simulation are two aspects of the scientific practice of high importance and have recently been discussed by philosophers of science. While verification is predominantly associated with the correctness of the way a model is represented by a computer code or algorithm, validation more often refers to model’s relation to the real world and its intended use. It has been argued that because complex simulations are generally not transparent to a practitioner, the Duhem problem can arise for verification and validation due to their entanglement; such an entanglement makes it impossible to distinguish whether a coding error or model’s general inadequacy to its target should be blamed in the case of the model failure. I argue that in order to disentangle verification and validation, a clear distinction between computer modeling (construction of mathematical computer models of elementary processes) and simulation (construction of models of composite objects and processes by means of numerical experimenting with them) needs to be made. Holding on to that distinction, I propose to relate verification (based on theoretical strategies such as inferences) to modeling and validation, which shares the common epistemology with experimentation, to simulation. To explain reasons of their intermittent entanglement I propose a weberian ideal-typical model of modeling and simulation as roles in practice. I suggest an approach to alleviate the Duhem problem for verification and validation generally applicable in practice and based on differences in epistemic strategies and scopes

  1. Computer Simulation Western

    International Nuclear Information System (INIS)

    Rasmussen, H.

    1992-01-01

    Computer Simulation Western is a unit within the Department of Applied Mathematics at the University of Western Ontario. Its purpose is the development of computational and mathematical methods for practical problems in industry and engineering and the application and marketing of such methods. We describe the unit and our efforts at obtaining research and development grants. Some representative projects will be presented and future plans discussed. (author)

  2. Accelerator simulation using computers

    International Nuclear Information System (INIS)

    Lee, M.; Zambre, Y.; Corbett, W.

    1992-01-01

    Every accelerator or storage ring system consists of a charged particle beam propagating through a beam line. Although a number of computer programs exits that simulate the propagation of a beam in a given beam line, only a few provide the capabilities for designing, commissioning and operating the beam line. This paper shows how a ''multi-track'' simulation and analysis code can be used for these applications

  3. Advanced computers and simulation

    International Nuclear Information System (INIS)

    Ryne, R.D.

    1993-01-01

    Accelerator physicists today have access to computers that are far more powerful than those available just 10 years ago. In the early 1980's, desktop workstations performed less one million floating point operations per second (Mflops), and the realized performance of vector supercomputers was at best a few hundred Mflops. Today vector processing is available on the desktop, providing researchers with performance approaching 100 Mflops at a price that is measured in thousands of dollars. Furthermore, advances in Massively Parallel Processors (MPP) have made performance of over 10 gigaflops a reality, and around mid-decade MPPs are expected to be capable of teraflops performance. Along with advances in MPP hardware, researchers have also made significant progress in developing algorithms and software for MPPS. These changes have had, and will continue to have, a significant impact on the work of computational accelerator physicists. Now, instead of running particle simulations with just a few thousand particles, we can perform desktop simulations with tens of thousands of simulation particles, and calculations with well over 1 million particles are being performed on MPPs. In the area of computational electromagnetics, simulations that used to be performed only on vector supercomputers now run in several hours on desktop workstations, and researchers are hoping to perform simulations with over one billion mesh points on future MPPs. In this paper we will discuss the latest advances, and what can be expected in the near future, in hardware, software and applications codes for advanced simulation of particle accelerators

  4. Computer Simulation of Reading.

    Science.gov (United States)

    Leton, Donald A.

    In recent years, coding and decoding have been claimed to be the processes for converting one language form to another. But there has been little effort to locate these processes in the human learner or to identify the nature of the internal codes. Computer simulation of reading is useful because the similarities in the human reception and…

  5. [Computer assisted orthognathic surgery: Condyle repositioning.

    Science.gov (United States)

    Bettega, G; Leitner, F

    2013-07-17

    Computer aided surgery has become a standard in many fields. It is rarely used in orthognathic surgery. Twenty years ago, we developed a navigation system adapted to this surgery, especially for mandibular condyle repositioning. The system has been improved along with technological progress. The authors of several clinical studies have validated this system. It is now routinely used in our department, because of its educational virtues among other assets. Copyright © 2013. Published by Elsevier Masson SAS.

  6. Computer security simulation

    International Nuclear Information System (INIS)

    Schelonka, E.P.

    1979-01-01

    Development and application of a series of simulation codes used for computer security analysis and design are described. Boolean relationships for arrays of barriers within functional modules are used to generate composite effectiveness indices. The general case of multiple layers of protection with any specified barrier survival criteria is given. Generalized reduction algorithms provide numerical security indices in selected subcategories and for the system as a whole. 9 figures, 11 tables

  7. Computed tomography-controlled stereotactic surgery

    International Nuclear Information System (INIS)

    Matsumoto, Keizo; Shichijo, Fumio; Gyoten, Tetsuya; Tomida, Keisuke; Miyake, Hajime

    1986-01-01

    A single use of coordinate system of computed tomography (CT) scanner is utilized for CT-controlled stereotactic surgery. Depth, direction and readjustment of target trajectory were defined by known values of cursor number in CT images and numbers of the sliding table indicator. We loaded calculation formulas into hand held computer to obtain immediate answers. Stereotactic apparatus consisted two main parts: the patient's head fixation and probe holder. Surgery was performed in cases of hypertensive intracerebral hemorrhage for evacuation of the hematomas successfully. Target accuracy was satisfactory. With further advance of this surgery, automatic stereotactic control with a special robot machine seeing possible. (author)

  8. Surgical simulators in cataract surgery training.

    Science.gov (United States)

    Sikder, Shameema; Tuwairqi, Khaled; Al-Kahtani, Eman; Myers, William G; Banerjee, Pat

    2014-02-01

    Virtual simulators have been widely implemented in medical and surgical training, including ophthalmology. The increasing number of published articles in this field mandates a review of the available results to assess current technology and explore future opportunities. A PubMed search was conducted and a total of 10 articles were reviewed. Virtual simulators have shown construct validity in many modules, successfully differentiating user experience levels during simulated phacoemulsification surgery. Simulators have also shown improvements in wet-lab performance. The implementation of simulators in the residency training has been associated with a decrease in cataract surgery complication rates. Virtual reality simulators are an effective tool in measuring performance and differentiating trainee skill level. Additionally, they may be useful in improving surgical skill and patient outcomes in cataract surgery. Future opportunities rely on taking advantage of technical improvements in simulators for education and research.

  9. Atomic-level computer simulation

    International Nuclear Information System (INIS)

    Adams, J.B.; Rockett, Angus; Kieffer, John; Xu Wei; Nomura, Miki; Kilian, K.A.; Richards, D.F.; Ramprasad, R.

    1994-01-01

    This paper provides a broad overview of the methods of atomic-level computer simulation. It discusses methods of modelling atomic bonding, and computer simulation methods such as energy minimization, molecular dynamics, Monte Carlo, and lattice Monte Carlo. ((orig.))

  10. Surgery simulation using fast finite elements

    DEFF Research Database (Denmark)

    Bro-Nielsen, Morten

    1996-01-01

    This paper describes our recent work on real-time surgery simulation using fast finite element models of linear elasticity. In addition, we discuss various improvements in terms of speed and realism......This paper describes our recent work on real-time surgery simulation using fast finite element models of linear elasticity. In addition, we discuss various improvements in terms of speed and realism...

  11. Computer assisted orthopaedic and trauma surgery. State of the art and future perspectives

    NARCIS (Netherlands)

    Schep, N. W. L.; Broeders, I. A. M. J.; van der Werken, Chr

    2003-01-01

    In recent years computer technologies have become more and more integrated in surgical procedures. The potential advantages of computer assisted surgery (CAS) are: increase of accuracy of surgical interventions, less invasive operations, better planning and simulation and reduction of radiation

  12. Simulation-based certification for cataract surgery

    DEFF Research Database (Denmark)

    Thomsen, Ann Sofia Skou; Kiilgaard, Jens Folke; Kjaerbo, Hadi

    2015-01-01

    PURPOSE: To evaluate the EyeSi(™) simulator in regard to assessing competence in cataract surgery. The primary objective was to explore all simulator metrics to establish a proficiency-based test with solid evidence. The secondary objective was to evaluate whether the skill assessment was specific...

  13. Low-Cost Simulation of Robotic Surgery

    DEFF Research Database (Denmark)

    Grande, Kasper; Jensen, Rasmus Steen; Kraus, Martin

    2013-01-01

    The high expenses associated with acquiring and maintaining robotic surgical equipment for minimally invasive surgery entail that training on this equipment is also expensive. Virtual reality (VR) training simulators can reduce this training time; however, the current simulators are also quite...

  14. Massively parallel quantum computer simulator

    NARCIS (Netherlands)

    De Raedt, K.; Michielsen, K.; De Raedt, H.; Trieu, B.; Arnold, G.; Richter, M.; Lippert, Th.; Watanabe, H.; Ito, N.

    2007-01-01

    We describe portable software to simulate universal quantum computers on massive parallel Computers. We illustrate the use of the simulation software by running various quantum algorithms on different computer architectures, such as a IBM BlueGene/L, a IBM Regatta p690+, a Hitachi SR11000/J1, a Cray

  15. Application of Simulated Three Dimensional CT Image in Orthognathic Surgery

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyun Don; Park, Chang Seo [Dept. of Dental Radiology, College of Dentistry, Yensei University, Seoul (Korea, Republic of); Yoo, Sun Kook; Lee, Kyoung Sang [Dept. of Medical Engineering, College of Medicine, Yensei University, Seoul (Korea, Republic of)

    1998-08-15

    In orthodontics and orthognathic surgery, cephalogram has been routine practice in diagnosis and treatment evaluation of craniofacial deformity. But its inherent distortion of actual length and angles during projecting three dimensional object to two dimensional plane might cause errors in quantitative analysis of shape and size. Therefore, it is desirable that three dimensional object is diagnosed and evaluated three dimensionally and three dimensional CT image is best for three dimensional analysis. Development of clinic necessitates evaluation of result of treatment and comparison before and after surgery. It is desirable that patient that was diagnosed and planned by three dimensional computed tomography before surgery is evaluated by three dimensional computed tomography after surgery, too. But Because there is no standardized normal values in three dimension now and three dimensional Computed Tomography needs expensive equipment and because of its expenses and amount of exposure to radiation, limitations still remain to be solved in its application to routine practice. If postoperative three dimensional image is constructed by pre and postoperative lateral and postero-anterior cephalograms and preoperative three dimensional computed tomogram, pre and postoperative image will be compared and evaluated three dimensionally without three dimensional computed tomography after surgery and that will contribute to standardize normal values in three dimension. This study introduced new method that computer-simulated three dimensional image was constructed by preoperative three dimensional computed tomogram and pre and postoperative lateral and postero-anterior cephalograms, and for validation of new method, in four cases of dry skull that position of mandible was displaced and four patients of orthognathic surgery, computer-simulated three dimensional image and actual postoperative three dimensional image were compared. The results were as follows. 1. In four cases of

  16. Application of Simulated Three Dimensional CT Image in Orthognathic Surgery

    International Nuclear Information System (INIS)

    Kim, Hyun Don; Park, Chang Seo; Yoo, Sun Kook; Lee, Kyoung Sang

    1998-01-01

    In orthodontics and orthognathic surgery, cephalogram has been routine practice in diagnosis and treatment evaluation of craniofacial deformity. But its inherent distortion of actual length and angles during projecting three dimensional object to two dimensional plane might cause errors in quantitative analysis of shape and size. Therefore, it is desirable that three dimensional object is diagnosed and evaluated three dimensionally and three dimensional CT image is best for three dimensional analysis. Development of clinic necessitates evaluation of result of treatment and comparison before and after surgery. It is desirable that patient that was diagnosed and planned by three dimensional computed tomography before surgery is evaluated by three dimensional computed tomography after surgery, too. But Because there is no standardized normal values in three dimension now and three dimensional Computed Tomography needs expensive equipment and because of its expenses and amount of exposure to radiation, limitations still remain to be solved in its application to routine practice. If postoperative three dimensional image is constructed by pre and postoperative lateral and postero-anterior cephalograms and preoperative three dimensional computed tomogram, pre and postoperative image will be compared and evaluated three dimensionally without three dimensional computed tomography after surgery and that will contribute to standardize normal values in three dimension. This study introduced new method that computer-simulated three dimensional image was constructed by preoperative three dimensional computed tomogram and pre and postoperative lateral and postero-anterior cephalograms, and for validation of new method, in four cases of dry skull that position of mandible was displaced and four patients of orthognathic surgery, computer-simulated three dimensional image and actual postoperative three dimensional image were compared. The results were as follows. 1. In four cases of

  17. Computer-Assisted Orthognathic Surgery for Patients with Cleft Lip/Palate: From Traditional Planning to Three-Dimensional Surgical Simulation

    Science.gov (United States)

    Lonic, Daniel; Pai, Betty Chien-Jung; Yamaguchi, Kazuaki; Chortrakarnkij, Peerasak; Lin, Hsiu-Hsia; Lo, Lun-Jou

    2016-01-01

    Background Although conventional two-dimensional (2D) methods for orthognathic surgery planning are still popular, the use of three-dimensional (3D) simulation is steadily increasing. In facial asymmetry cases such as in cleft lip/palate patients, the additional information can dramatically improve planning accuracy and outcome. The purpose of this study is to investigate which parameters are changed most frequently in transferring a traditional 2D plan to 3D simulation, and what planning parameters can be better adjusted by this method. Patients and Methods This prospective study enrolled 30 consecutive patients with cleft lip and/or cleft palate (mean age 18.6±2.9 years, range 15 to 32 years). All patients received two-jaw single-splint orthognathic surgery. 2D orthodontic surgery plans were transferred into a 3D setting. Severe bony collisions in the ramus area after 2D plan transfer were noted. The position of the maxillo-mandibular complex was evaluated and eventually adjusted. Position changes of roll, midline, pitch, yaw, genioplasty and their frequency within the patient group were recorded as an alternation of the initial 2D plan. Patients were divided in groups of no change from the original 2D plan and changes in one, two, three and four of the aforementioned parameters as well as subgroups of unilateral, bilateral cleft lip/palate and isolated cleft palate cases. Postoperative OQLQ scores were obtained for 20 patients who finished orthodontic treatment. Results 83.3% of 2D plans were modified, mostly concerning yaw (63.3%) and midline (36.7%) adjustments. Yaw adjustments had the highest mean values in total and in all subgroups. Severe bony collisions as a result of 2D planning were seen in 46.7% of patients. Possible asymmetry was regularly foreseen and corrected in the 3D simulation. Conclusion Based on our findings, 3D simulation renders important information for accurate planning in complex cleft lip/palate cases involving facial asymmetry that is

  18. Computer-Assisted Orthognathic Surgery for Patients with Cleft Lip/Palate: From Traditional Planning to Three-Dimensional Surgical Simulation.

    Directory of Open Access Journals (Sweden)

    Daniel Lonic

    Full Text Available Although conventional two-dimensional (2D methods for orthognathic surgery planning are still popular, the use of three-dimensional (3D simulation is steadily increasing. In facial asymmetry cases such as in cleft lip/palate patients, the additional information can dramatically improve planning accuracy and outcome. The purpose of this study is to investigate which parameters are changed most frequently in transferring a traditional 2D plan to 3D simulation, and what planning parameters can be better adjusted by this method.This prospective study enrolled 30 consecutive patients with cleft lip and/or cleft palate (mean age 18.6±2.9 years, range 15 to 32 years. All patients received two-jaw single-splint orthognathic surgery. 2D orthodontic surgery plans were transferred into a 3D setting. Severe bony collisions in the ramus area after 2D plan transfer were noted. The position of the maxillo-mandibular complex was evaluated and eventually adjusted. Position changes of roll, midline, pitch, yaw, genioplasty and their frequency within the patient group were recorded as an alternation of the initial 2D plan. Patients were divided in groups of no change from the original 2D plan and changes in one, two, three and four of the aforementioned parameters as well as subgroups of unilateral, bilateral cleft lip/palate and isolated cleft palate cases. Postoperative OQLQ scores were obtained for 20 patients who finished orthodontic treatment.83.3% of 2D plans were modified, mostly concerning yaw (63.3% and midline (36.7% adjustments. Yaw adjustments had the highest mean values in total and in all subgroups. Severe bony collisions as a result of 2D planning were seen in 46.7% of patients. Possible asymmetry was regularly foreseen and corrected in the 3D simulation.Based on our findings, 3D simulation renders important information for accurate planning in complex cleft lip/palate cases involving facial asymmetry that is regularly missed in conventional 2D

  19. [Basic concept in computer assisted surgery].

    Science.gov (United States)

    Merloz, Philippe; Wu, Hao

    2006-03-01

    To investigate application of medical digital imaging systems and computer technologies in orthopedics. The main computer-assisted surgery systems comprise the four following subcategories. (1) A collection and recording process for digital data on each patient, including preoperative images (CT scans, MRI, standard X-rays), intraoperative visualization (fluoroscopy, ultrasound), and intraoperative position and orientation of surgical instruments or bone sections (using 3D localises). Data merging based on the matching of preoperative imaging (CT scans, MRI, standard X-rays) and intraoperative visualization (anatomical landmarks, or bone surfaces digitized intraoperatively via 3D localiser; intraoperative ultrasound images processed for delineation of bone contours). (2) In cases where only intraoperative images are used for computer-assisted surgical navigation, the calibration of the intraoperative imaging system replaces the merged data system, which is then no longer necessary. (3) A system that provides aid in decision-making, so that the surgical approach is planned on basis of multimodal information: the interactive positioning of surgical instruments or bone sections transmitted via pre- or intraoperative images, display of elements to guide surgical navigation (direction, axis, orientation, length and diameter of a surgical instrument, impingement, etc. ). And (4) A system that monitors the surgical procedure, thereby ensuring that the optimal strategy defined at the preoperative stage is taken into account. It is possible that computer-assisted orthopedic surgery systems will enable surgeons to better assess the accuracy and reliability of the various operative techniques, an indispensable stage in the optimization of surgery.

  20. Mechatronics Interface for Computer Assisted Prostate Surgery Training

    Science.gov (United States)

    Altamirano del Monte, Felipe; Padilla Castañeda, Miguel A.; Arámbula Cosío, Fernando

    2006-09-01

    In this work is presented the development of a mechatronics device to simulate the interaction of the surgeon with the surgical instrument (resectoscope) used during a Transurethral Resection of the Prostate (TURP). Our mechatronics interface is part of a computer assisted system for training in TURP, which is based on a 3D graphics model of the prostate which can be deformed and resected interactively by the user. The mechatronics interface, is the device that the urology residents will manipulate to simulate the movements performed during surgery. Our current prototype has five degrees of freedom, which are enough to have a realistic simulation of the surgery movements. Two of these degrees of freedom are linear, to determinate the linear displacement of the resecting loop and the other three are rotational to determinate three directions and amounts of rotation.

  1. Fast finite elements for surgery simulation

    DEFF Research Database (Denmark)

    Bro-Nielsen, Morten

    1997-01-01

    This paper discusses volumetric deformable models for modeling human body parts and organs in surgery simulation systems. These models are built using finite element models for linear elastic materials. To achieve real-time response condensation has been applied to the system stiffness matrix...

  2. Incorporating simulation in vascular surgery education.

    Science.gov (United States)

    Bismuth, Jean; Donovan, Michael A; O'Malley, Marcia K; El Sayed, Hosam F; Naoum, Joseph J; Peden, Eric K; Davies, Mark G; Lumsden, Alan B

    2010-10-01

    The traditional apprenticeship model introduced by Halsted of "learning by doing" may just not be valid in the modern practice of vascular surgery. The model is often criticized for being somewhat unstructured because a resident's experience is based on what comes through the "door." In an attempt to promote uniformity of training, multiple national organizations are currently delineating standard curricula for each trainee to govern the knowledge and cases required in a vascular residency. However, the outcomes are anything but uniform. This means that we graduate vascular specialists with a surprisingly wide spectrum of abilities. Use of simulation may benefit trainees in attaining a level of technical expertise that will benefit themselves and their patients. Furthermore, there is likely a need to establish a simulation-based certification process for graduating trainees to further ascertain minimum technical abilities. Copyright © 2010 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.

  3. Computer Simulation of Mutagenesis.

    Science.gov (United States)

    North, J. C.; Dent, M. T.

    1978-01-01

    A FORTRAN program is described which simulates point-substitution mutations in the DNA strands of typical organisms. Its objective is to help students to understand the significance and structure of the genetic code, and the mechanisms and effect of mutagenesis. (Author/BB)

  4. Fluid simulation for computer graphics

    CERN Document Server

    Bridson, Robert

    2008-01-01

    Animating fluids like water, smoke, and fire using physics-based simulation is increasingly important in visual effects, in particular in movies, like The Day After Tomorrow, and in computer games. This book provides a practical introduction to fluid simulation for graphics. The focus is on animating fully three-dimensional incompressible flow, from understanding the math and the algorithms to the actual implementation.

  5. Fel simulations using distributed computing

    NARCIS (Netherlands)

    Einstein, J.; Biedron, S.G.; Freund, H.P.; Milton, S.V.; Van Der Slot, P. J M; Bernabeu, G.

    2016-01-01

    While simulation tools are available and have been used regularly for simulating light sources, including Free-Electron Lasers, the increasing availability and lower cost of accelerated computing opens up new opportunities. This paper highlights a method of how accelerating and parallelizing code

  6. Simulation training in video-assisted urologic surgery.

    Science.gov (United States)

    Hoznek, András; Salomon, Laurent; de la Taille, Alexandre; Yiou, René; Vordos, Dimitrios; Larre, Stéphane; Abbou, Clément-Claude

    2006-03-01

    The current system of surgical education is facing many challenges in terms of time efficiency, costs, and patient safety. Training using simulation is an emerging area, mostly based on the experience of other high-risk professions like aviation. The goal of simulation-based training in surgery is to develop not only technical but team skills. This learning environment is stress-free and safe, allows standardization and tailoring of training, and also objectively evaluate performances. The development of simulation training is straightforward in endourology, since these procedures are video-assisted and the low degree of freedom of the instruments is easily replicated. On the other hand, these interventions necessitate a long learning curve, training in the operative room is especially costly and risky. Many models are already in use or under development in all fields of video-assisted urologic surgery: ureteroscopy, percutaneous surgery, transurethral resection of the prostate, and laparoscopy. Although bench models are essential, simulation increasingly benefits from the achievements and development of computer technology. Still in its infancy, virtual reality simulation will certainly belong to tomorrow's teaching tools.

  7. Computer simulation of oxides

    International Nuclear Information System (INIS)

    Rowley, A.

    1998-01-01

    An ionic interaction model is developed which accounts for the effects of the ionic environment upon the electron densities of both cations and anions through changes in their size and shape and is transferable between materials. These variations are represented by additional dynamical variables which are handled within the model using the techniques of the Car-Parrinello method. The model parameters are determined as far as possible by input from external ab initio electronic structure calculations directed at examining the individual effects of the ionic environment upon the ions, particularly the oxide ion. Techniques for the evaluation of dipolar and quadrupolar Ewald sums in non-cubic simulation cells and the calculation of the pressure due to the terms in the potential are presented. This model is applied to the description of the perfect crystal properties and phonon dispersion curves of MgO. Consideration of the high symmetry phonon modes allows parameterization of the remaining model parameters in an unambiguous fashion. The same procedure is used to obtain parameters for CaO. These two parameter sets are examined to determine how they may be used to generate the parameters for SrO and simple scaling relationships based on ionic radii and polarizabilities are formulated. The transferability of the model to Cr 2 O 3 is investigated using parameters generated from the alkaline earth oxides. The importance of lower symmetry model terms, particularly quadrupolar interactions, at the low symmetry ion sites in the crystal structure is demonstrated. The correct ground-state crystal structure is predicted and the calculated surface energies and relaxation phenomena are found to agree well with previous ab initio studies. The model is applied to GeO 2 as a strong test of its applicability to ion environments far different from those encountered in MgO. An good description of the crystal structures is obtained and the interplay of dipolar and quadrupolar effects is

  8. Simulating chemistry using quantum computers.

    Science.gov (United States)

    Kassal, Ivan; Whitfield, James D; Perdomo-Ortiz, Alejandro; Yung, Man-Hong; Aspuru-Guzik, Alán

    2011-01-01

    The difficulty of simulating quantum systems, well known to quantum chemists, prompted the idea of quantum computation. One can avoid the steep scaling associated with the exact simulation of increasingly large quantum systems on conventional computers, by mapping the quantum system to another, more controllable one. In this review, we discuss to what extent the ideas in quantum computation, now a well-established field, have been applied to chemical problems. We describe algorithms that achieve significant advantages for the electronic-structure problem, the simulation of chemical dynamics, protein folding, and other tasks. Although theory is still ahead of experiment, we outline recent advances that have led to the first chemical calculations on small quantum information processors.

  9. Computer simulation of ductile fracture

    International Nuclear Information System (INIS)

    Wilkins, M.L.; Streit, R.D.

    1979-01-01

    Finite difference computer simulation programs are capable of very accurate solutions to problems in plasticity with large deformations and rotation. This opens the possibility of developing models of ductile fracture by correlating experiments with equivalent computer simulations. Selected experiments were done to emphasize different aspects of the model. A difficult problem is the establishment of a fracture-size effect. This paper is a study of the strain field around notched tensile specimens of aluminum 6061-T651. A series of geometrically scaled specimens are tested to fracture. The scaled experiments are conducted for different notch radius-to-diameter ratios. The strains at fracture are determined from computer simulations. An estimate is made of the fracture-size effect

  10. Computer Assisted Orthopaedic Surgery – CAOS

    Directory of Open Access Journals (Sweden)

    Enes M. Kanlić

    2006-02-01

    Full Text Available The use of computer navigation in orthopedic surgery allows for real time intraoperative feedback resulting in higher precision of bone cuts, better alignment of implants and extremities, easier fracture reductions, less radiation and better documentation than what is possible in classical orthopaedic procedures. There is no need for direct and repeated visualization of many anatomical landmarks (classical method in order to have good intraoperative orientation. Navigation technology depicts anatomy and position of "smart tools" on the screen allowing for high surgical precision (smaller number of outliers from desired goal and with less soft tissue dissection (minimally invasive surgery - MIS. As a result, there are more happy patients with less pain, faster recovery, better functional outcome and well positioned, long lasting implants. In general, navigation cases are longer on the average 10 to 20 minutes, special training is required and equipment is relatively expensive. CAOS applications in knee and hip joint replacement are discussed.

  11. Surgical robot setup simulation with consistent kinematics and haptics for abdominal surgery.

    Science.gov (United States)

    Hayashibe, Mitsuhiro; Suzuki, Naoki; Hattori, Asaki; Suzuki, Shigeyuki; Konishi, Kozo; Kakeji, Yoshihiro; Hashizume, Makoto

    2005-01-01

    Preoperative simulation and planning of surgical robot setup should accompany advanced robotic surgery if their advantages are to be further pursued. Feedback from the planning system will plays an essential role in computer-aided robotic surgery in addition to preoperative detailed geometric information from patient CT/MRI images. Surgical robot setup simulation systems for appropriate trocar site placement have been developed especially for abdominal surgery. The motion of the surgical robot can be simulated and rehearsed with kinematic constraints at the trocar site, and the inverse-kinematics of the robot. Results from simulation using clinical patient data verify the effectiveness of the proposed system.

  12. Medical Image Registration and Surgery Simulation

    DEFF Research Database (Denmark)

    Bro-Nielsen, Morten

    1996-01-01

    This thesis explores the application of physical models in medical image registration and surgery simulation. The continuum models of elasticity and viscous fluids are described in detail, and this knowledge is used as a basis for most of the methods described here. Real-time deformable models......, and the use of selective matrix vector multiplication. Fluid medical image registration A new and faster algorithm for non-rigid registration using viscous fluid models is presented. This algorithm replaces the core part of the original algorithm with multi-resolution convolution using a new filter, which...... growth is also presented. Using medical knowledge about the growth processes of the mandibular bone, a registration algorithm for time sequence images of the mandible is developed. Since this registration algorithm models the actual development of the mandible, it is possible to simulate the development...

  13. Computer Simulation of Diffraction Patterns.

    Science.gov (United States)

    Dodd, N. A.

    1983-01-01

    Describes an Apple computer program (listing available from author) which simulates Fraunhofer and Fresnel diffraction using vector addition techniques (vector chaining) and allows user to experiment with different shaped multiple apertures. Graphics output include vector resultants, phase difference, diffraction patterns, and the Cornu spiral…

  14. Computer Based Modelling and Simulation

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 6; Issue 3. Computer Based Modelling and Simulation - Modelling Deterministic Systems. N K Srinivasan. General Article Volume 6 Issue 3 March 2001 pp 46-54. Fulltext. Click here to view fulltext PDF. Permanent link:

  15. Biomass Gasifier for Computer Simulation; Biomassa foergasare foer Computer Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Hansson, Jens; Leveau, Andreas; Hulteberg, Christian [Nordlight AB, Limhamn (Sweden)

    2011-08-15

    This report is an effort to summarize the existing data on biomass gasifiers as the authors have taken part in various projects aiming at computer simulations of systems that include biomass gasification. Reliable input data is paramount for any computer simulation, but so far there is no easy-accessible biomass gasifier database available for this purpose. This study aims at benchmarking current and past gasifier systems in order to create a comprehensive database for computer simulation purposes. The result of the investigation is presented in a Microsoft Excel sheet, so that the user easily can implement the data in their specific model. In addition to provide simulation data, the technology is described briefly for every studied gasifier system. The primary pieces of information that are sought for are temperatures, pressures, stream compositions and energy consumption. At present the resulting database contains 17 gasifiers, with one or more gasifier within the different gasification technology types normally discussed in this context: 1. Fixed bed 2. Fluidised bed 3. Entrained flow. It also contains gasifiers in the range from 100 kW to 120 MW, with several gasifiers in between these two values. Finally, there are gasifiers representing both direct and indirect heating. This allows for a more qualified and better available choice of starting data sets for simulations. In addition to this, with multiple data sets available for several of the operating modes, sensitivity analysis of various inputs will improve simulations performed. However, there have been fewer answers to the survey than expected/hoped for, which could have improved the database further. However, the use of online sources and other public information has to some extent counterbalanced the low response frequency of the survey. In addition to that, the database is preferred to be a living document, continuously updated with new gasifiers and improved information on existing gasifiers.

  16. Virtual reality applied to hepatic surgery simulation: the next revolution.

    Science.gov (United States)

    Marescaux, J; Clément, J M; Tassetti, V; Koehl, C; Cotin, S; Russier, Y; Mutter, D; Delingette, H; Ayache, N

    1998-11-01

    This article describes a preliminary work on virtual reality applied to liver surgery and discusses the repercussions of assisted surgical strategy and surgical simulation on tomorrow's surgery. Liver surgery is considered difficult because of the complexity and variability of the organ. Common generic tools for presurgical medical image visualization do not fulfill the requirements for the liver, restricting comprehension of a patient's specific liver anatomy. Using data from the National Library of Medicine, a realistic three-dimensional image was created, including the envelope and the four internal arborescences. A computer interface was developed to manipulate the organ and to define surgical resection planes according to internal anatomy. The first step of surgical simulation was implemented, providing the organ with real-time deformation computation. The three-dimensional anatomy of the liver could be clearly visualized. The virtual organ could be manipulated and a resection defined depending on the anatomic relations between the arborescences, the tumor, and the external envelope. The resulting parts could also be visualized and manipulated. The simulation allowed the deformation of a liver model in real time by means of a realistic laparoscopic tool. Three-dimensional visualization of the organ in relation to the pathology is of great help to appreciate the complex anatomy of the liver. Using virtual reality concepts (navigation, interaction, and immersion), surgical planning, training, and teaching for this complex surgical procedure may be possible. The ability to practice a given gesture repeatedly will revolutionize surgical training, and the combination of surgical planning and simulation will improve the efficiency of intervention, leading to optimal care delivery.

  17. Accuracy of computer-assisted orthognathic surgery.

    Science.gov (United States)

    De Riu, Giacomo; Virdis, Paola Ilaria; Meloni, Silvio Mario; Lumbau, Aurea; Vaira, Luigi Angelo

    2018-02-01

    The purpose of this study was to retrospectively evaluate the difference between the planned and the actual movements of the jaws, using three-dimensional (3D) software for PC-assisted orthognathic surgery, to establish the accuracy of the procedure. A retrospective study was performed with 49 patients who had undergone PC-guided bimaxillary surgery. The accuracy of the protocol was determined by comparing planned movements of the jaws with the actual surgical movements, analysing frontal and lateral cephalometries. The overall results were deemed accurate, and differences among 12 of the 15 parameters were considered nonsignificant. Significant differences were reported for SNA (p = 0.008), SNB (p = 0.006), and anterior facial height (p = 0.033). The latter was significantly different in patients who had undergone genioplasty when compared with patients who had not. Virtual surgical planning presented a good degree of accuracy for most of the parameters assessed, with an average error of 1.98 mm for linear measures and 1.19° for angular measures. In general, a tendency towards under-projection in jaws was detected, probably due to imperfect condylar seating. A slight overcorrection of SNA and SNB during virtual planning (approximately 2°) could be beneficial. Further progress is required in the development of 3D simulation of the soft tissue, which currently does not allow an accurate management of the facial height and the chin position. Virtual planning cannot replace the need for constant intraoperative monitoring of the jaws' movements and real-time comparisons between planned and actual outcomes. It is therefore appropriate to leave some margin for correction of inaccuracies in the virtual planning. In this sense, it may be appropriate to use only the intermediate splint, and then use the planned occlusion and clinical measurements to guide repositioning of the second jaw and chin, respectively. Copyright © 2017 European Association for Cranio

  18. Computer simulation in cell radiobiology

    International Nuclear Information System (INIS)

    Yakovlev, A.Y.; Zorin, A.V.

    1988-01-01

    This research monograph demonstrates the possible ways of using stochastic simulation for exploring cell kinetics, emphasizing the effects of cell radiobiology. In vitro kinetics of normal and irradiated cells is the main subject, but some approaches to the simulation of controlled cell systems are considered as well: the epithelium of the small intestine in mice taken as a case in point. Of particular interest is the evaluation of simulation modelling as a tool for gaining insight into biological processes and hence the new inferences from concrete experimental data, concerning regularities in cell population response to irradiation. The book is intended to stimulate interest among computer science specialists in developing new, more efficient means for the simulation of cell systems and to help radiobiologists in interpreting the experimental data

  19. Computer in surgery | Bode | Nigerian Journal of Surgical Research

    African Journals Online (AJOL)

    How has the advent of the computer impacted the field of surgery? Is it worth embracing for the older practitioners? What does the future portend for our ancient noble profession? This paper reviews current applications of computer technology in the field of surgery and the hopes it hold out to surgeons in developing ...

  20. Computed tomography angiogram. Accuracy in renal surgery

    International Nuclear Information System (INIS)

    Rabah, Danny M.; Al-Hathal, Naif; Al-Fuhaid, Turki; Raza, Sayed; Al-Yami, Fahad; Al-Taweel, Waleed; Alomar, Mohamed; Al-Nagshabandi, Nizar

    2009-01-01

    The objective of this study was to determine the sensitivity and specificity of computed tomography angiogram (CTA) in detecting number and location of renal arteries and veins as well as crossing vessels causing uretero-pelvic junction obstruction (UPJO), and to determine if this can be used in decision-making algorithms for treatment of UPJO. A prospective study was carried out in patients undergoing open, laparoscopic and robotic renal surgery from April 2005 until October 2006. All patients were imaged using CTA with 1.25 collimation of arterial and venous phases. Each multi-detector CTA was then read by one radiologist and his results were compared prospectively with the actual intra-operative findings. Overall, 118 patients were included. CTA had 93% sensitivity, 77% specificity and 90% overall accuracy for detecting a single renal artery, and 76% sensitivity, 92% specificity and 90% overall accuracy for detecting two or more renal arteries (Pearson χ 2 =0.001). There was 95% sensitivity, 84% specificity and 85% overall accuracy for detecting the number of renal veins. CTA had 100% overall accuracy in detecting early dividing renal artery (defined as less than 1.5 cm branching from origin), and 83.3% sensitivity, specificity and overall accuracy in detecting crossing vessels at UPJ. The percentage of surgeons stating CTA to be helpful as pre-operative diagnostic tool was 85%. Computed tomography angiogram is simple, quick and can provide an accurate pre-operative renal vascular anatomy in terms of number and location of renal vessels, early dividing renal arteries and crossing vessels at UPJ. (author)

  1. Design-Based Comparison of Spine Surgery Simulators: Optimizing Educational Features of Surgical Simulators.

    Science.gov (United States)

    Ryu, Won Hyung A; Mostafa, Ahmed E; Dharampal, Navjit; Sharlin, Ehud; Kopp, Gail; Jacobs, W Bradley; Hurlbert, R John; Chan, Sonny; Sutherland, Garnette R

    2017-10-01

    Simulation-based education has made its entry into surgical residency training, particularly as an adjunct to hands-on clinical experience. However, one of the ongoing challenges to wide adoption is the capacity of simulators to incorporate educational features required for effective learning. The aim of this study was to identify strengths and limitations of spine simulators to characterize design elements that are essential in enhancing resident education. We performed a mixed qualitative and quantitative cohort study with a focused survey and interviews of stakeholders in spine surgery pertaining to their experiences on 3 spine simulators. Ten participants were recruited spanning all levels of training and expertise until qualitative analysis reached saturation of themes. Participants were asked to perform lumbar pedicle screw insertion on 3 simulators. Afterward, a 10-item survey was administrated and a focused interview was conducted to explore topics pertaining to the design features of the simulators. Overall impressions of the simulators were positive with regards to their educational benefit, but our qualitative analysis revealed differing strengths and limitations. Main design strengths of the computer-based simulators were incorporation of procedural guidance and provision of performance feedback. The synthetic model excelled in achieving more realistic haptic feedback and incorporating use of actual surgical tools. Stakeholders from trainees to experts acknowledge the growing role of simulation-based education in spine surgery. However, different simulation modalities have varying design elements that augment learning in distinct ways. Characterization of these design characteristics will allow for standardization of simulation curricula in spinal surgery, optimizing educational benefit. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Biomes computed from simulated climatologies

    Energy Technology Data Exchange (ETDEWEB)

    Claussen, M.; Esch, M. [Max-Planck-Institut fuer Meteorologie, Hamburg (Germany)

    1994-01-01

    The biome model of Prentice et al. is used to predict global patterns of potential natural plant formations, or biomes, from climatologies simulated by ECHAM, a model used for climate simulations at the Max-Planck-Institut fuer Meteorologie. This study undertaken in order to show the advantage of this biome model in diagnosing the performance of a climate model and assessing effects of past and future climate changes predicted by a climate model. Good overall agreement is found between global patterns of biomes computed from observed and simulated data of present climate. But there are also major discrepancies indicated by a difference in biomes in Australia, in the Kalahari Desert, and in the Middle West of North America. These discrepancies can be traced back to in simulated rainfall as well as summer or winter temperatures. Global patterns of biomes computed from an ice age simulation reveal that North America, Europe, and Siberia should have been covered largely by tundra and taiga, whereas only small differences are for the tropical rain forests. A potential northeast shift of biomes is expected from a simulation with enhanced CO{sub 2} concentration according to the IPCC Scenario A. Little change is seen in the tropical rain forest and the Sahara. Since the biome model used is not capable of predicting chances in vegetation patterns due to a rapid climate change, the latter simulation to be taken as a prediction of chances in conditions favourable for the existence of certain biomes, not as a reduction of a future distribution of biomes. 15 refs., 8 figs., 2 tabs.

  3. Biomes computed from simulated climatologies

    Energy Technology Data Exchange (ETDEWEB)

    Claussen, W.; Esch, M.

    1992-09-01

    The biome model of Prentice et al. is used to predict global patterns of potential natural plant formations, or biomes, from climatologies simulated by ECHAM, a model used for climate simulations at the Max-Planck-Institut fuer Meteorologie. This study is undertaken in order to show the advantage of this biome model in comprehensively diagnosing the performance of a climate model and assessing effects of past and future climate changes predicted by a climate model. Good overall agreement is found between global patterns of biomes computed from observed and simulated data of present climate. But there are also major discrepancies indicated by a difference in biomes in Australia, in the Kalahari Desert, and in the Middle West of North America. These discrepancies can be traced back to failures in simulated rain fall as well as summer or winter temperatures. Global patterns of biomes computed from an ice age simulation reveal that North America, Europe, and Siberia should have been covered largely by tundra and taiga, whereas only small differences are seen for the tropical rain forests. A potential North-East shift of biomes is expected from a simulation with enhanced CO{sub 2} concentration according to the IPCC Scenario A. Little change is seen in the tropical rain forest and the Sahara. Since the biome model used is not capable of predicting changes in vegetation patterns due to a rapid climate change, the latter simulation has to be taken as a prediction of changes in conditions favorable for the existence of certain biomes, not as a prediction of a future distribution of biomes. (orig.).

  4. Computer assisted surgery in preoperative planning of acetabular fracture surgery: state of the art.

    Science.gov (United States)

    Boudissa, Mehdi; Courvoisier, Aurélien; Chabanas, Matthieu; Tonetti, Jérôme

    2018-01-01

    The development of imaging modalities and computer technology provides a new approach in acetabular surgery. Areas covered: This review describes the role of computer-assisted surgery (CAS) in understanding of the fracture patterns, in the virtual preoperative planning of the surgery and in the use of custom-made plates in acetabular fractures with or without 3D printing technologies. A Pubmed internet research of the English literature of the last 20 years was carried out about studies concerning computer-assisted surgery in acetabular fractures. The several steps for CAS in acetabular fracture surgery are presented and commented by the main author regarding to his personal experience. Expert commentary: Computer-assisted surgery in acetabular fractures is still initial experiences with promising results. Patient-specific biomechanical models considering soft tissues should be developed to allow a more realistic planning.

  5. Computational simulator of robotic manipulators

    International Nuclear Information System (INIS)

    Leal, Alexandre S.; Campos, Tarcisio P.R.

    1995-01-01

    Robotic application for industrial plants is discussed and a computational model for a mechanical manipulator of three links is presented. A neural network feed-forward type has been used to model the dynamic control of the manipulator. A graphic interface was developed in C programming language as a virtual world in order to visualize and simulate the arm movements handling radioactive waste environment. (author). 7 refs, 5 figs

  6. Computer simulation of nonequilibrium processes

    International Nuclear Information System (INIS)

    Wallace, D.C.

    1985-07-01

    The underlying concepts of nonequilibrium statistical mechanics, and of irreversible thermodynamics, will be described. The question at hand is then, how are these concepts to be realize in computer simulations of many-particle systems. The answer will be given for dissipative deformation processes in solids, on three hierarchical levels: heterogeneous plastic flow, dislocation dynamics, an molecular dynamics. Aplication to the shock process will be discussed

  7. Computer simulation of liquid crystals

    International Nuclear Information System (INIS)

    McBride, C.

    1999-01-01

    Molecular dynamics simulation performed on modern computer workstations provides a powerful tool for the investigation of the static and dynamic characteristics of liquid crystal phases. In this thesis molecular dynamics computer simulations have been performed for two model systems. Simulations of 4,4'-di-n-pentyl-bibicyclo[2.2.2]octane demonstrate the growth of a structurally ordered phase directly from an isotropic fluid. This is the first time that this has been achieved for an atomistic model. The results demonstrate a strong coupling between orientational ordering and molecular shape, but indicate that the coupling between molecular conformational changes and molecular reorientation is relatively weak. Simulations have also been performed for a hybrid Gay-Berne/Lennard-Jones model resulting in thermodynamically stable nematic and smectic phases. Frank elastic constants have been calculated for the nematic phase formed by the hybrid model through analysis of the fluctuations of the nematic director, giving results comparable with those found experimentally. Work presented in this thesis also describes the parameterization of the torsional potential of a fragment of a dimethyl siloxane polymer chain, disiloxane diol (HOMe 2 Si) 2 O, using ab initio quantum mechanical calculations. (author)

  8. Inversion based on computational simulations

    International Nuclear Information System (INIS)

    Hanson, K.M.; Cunningham, G.S.; Saquib, S.S.

    1998-01-01

    A standard approach to solving inversion problems that involve many parameters uses gradient-based optimization to find the parameters that best match the data. The authors discuss enabling techniques that facilitate application of this approach to large-scale computational simulations, which are the only way to investigate many complex physical phenomena. Such simulations may not seem to lend themselves to calculation of the gradient with respect to numerous parameters. However, adjoint differentiation allows one to efficiently compute the gradient of an objective function with respect to all the variables of a simulation. When combined with advanced gradient-based optimization algorithms, adjoint differentiation permits one to solve very large problems of optimization or parameter estimation. These techniques will be illustrated through the simulation of the time-dependent diffusion of infrared light through tissue, which has been used to perform optical tomography. The techniques discussed have a wide range of applicability to modeling including the optimization of models to achieve a desired design goal

  9. Parallel Computing for Brain Simulation.

    Science.gov (United States)

    Pastur-Romay, L A; Porto-Pazos, A B; Cedron, F; Pazos, A

    2017-01-01

    The human brain is the most complex system in the known universe, it is therefore one of the greatest mysteries. It provides human beings with extraordinary abilities. However, until now it has not been understood yet how and why most of these abilities are produced. For decades, researchers have been trying to make computers reproduce these abilities, focusing on both understanding the nervous system and, on processing data in a more efficient way than before. Their aim is to make computers process information similarly to the brain. Important technological developments and vast multidisciplinary projects have allowed creating the first simulation with a number of neurons similar to that of a human brain. This paper presents an up-to-date review about the main research projects that are trying to simulate and/or emulate the human brain. They employ different types of computational models using parallel computing: digital models, analog models and hybrid models. This review includes the current applications of these works, as well as future trends. It is focused on various works that look for advanced progress in Neuroscience and still others which seek new discoveries in Computer Science (neuromorphic hardware, machine learning techniques). Their most outstanding characteristics are summarized and the latest advances and future plans are presented. In addition, this review points out the importance of considering not only neurons: Computational models of the brain should also include glial cells, given the proven importance of astrocytes in information processing. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  10. FPGA-accelerated simulation of computer systems

    CERN Document Server

    Angepat, Hari; Chung, Eric S; Hoe, James C; Chung, Eric S

    2014-01-01

    To date, the most common form of simulators of computer systems are software-based running on standard computers. One promising approach to improve simulation performance is to apply hardware, specifically reconfigurable hardware in the form of field programmable gate arrays (FPGAs). This manuscript describes various approaches of using FPGAs to accelerate software-implemented simulation of computer systems and selected simulators that incorporate those techniques. More precisely, we describe a simulation architecture taxonomy that incorporates a simulation architecture specifically designed f

  11. Computer simulation of hopper flow

    International Nuclear Information System (INIS)

    Potapov, A.V.; Campbell, C.S.

    1996-01-01

    This paper describes two-dimensional computer simulations of granular flow in plane hoppers. The simulations can reproduce an experimentally observed asymmetric unsteadiness for monodispersed particle sizes, but also could eliminate it by adding a small amount of polydispersity. This appears to be a result of the strong packings that may be formed by monodispersed particles and is thus a noncontinuum effect. The internal stress state was also sampled, which among other things, allows an evaluation of common assumptions made in granular material models. These showed that the internal friction coefficient is far from a constant, which is in contradiction to common models based on plasticity theory which assume that the material is always at the point of imminent yield. Furthermore, it is demonstrated that rapid granular flow theory, another common modeling technique, is inapplicable to this problem even near the exit where the flow is moving its fastest. copyright 1996 American Institute of Physics

  12. CARS 2009. Computer assisted radiology and surgery. Proceedings

    International Nuclear Information System (INIS)

    Anon.

    2009-01-01

    The CARS 2009 proceedings include contributions and poster sessions concerning different conferences and workshops: computer assisted radiology, 23rd international congress and exhibition, CARS clinical day, 13th annual conference of the international society for computer aided surgery, 10th CARS/SPIE/EuroPACS joint workshop on surgical PACS and the digital operating, 11th international workshop on computer-aided diagnosis, 15th computed maxillofacial imaging congress, CARS - computer assisted radiology and surgery, 1st EPMA/CARS workshop on personalized medicine and ICT, JICARS - Japanese institutes of CARS, 1st EuroNotes/CTAC/CARS workshop on NOTES: an interdisciplinary challenge, 13th annual conference for computer aided surgery, 27th international EuroPACS meeting.

  13. 20170312 - Computer Simulation of Developmental ...

    Science.gov (United States)

    Rationale: Recent progress in systems toxicology and synthetic biology have paved the way to new thinking about in vitro/in silico modeling of developmental processes and toxicities, both for embryological and reproductive impacts. Novel in vitro platforms such as 3D organotypic culture models, engineered microscale tissues and complex microphysiological systems (MPS), together with computational models and computer simulation of tissue dynamics, lend themselves to a integrated testing strategies for predictive toxicology. As these emergent methodologies continue to evolve, they must be integrally tied to maternal/fetal physiology and toxicity of the developing individual across early lifestage transitions, from fertilization to birth, through puberty and beyond. Scope: This symposium will focus on how the novel technology platforms can help now and in the future, with in vitro/in silico modeling of complex biological systems for developmental and reproductive toxicity issues, and translating systems models into integrative testing strategies. The symposium is based on three main organizing principles: (1) that novel in vitro platforms with human cells configured in nascent tissue architectures with a native microphysiological environments yield mechanistic understanding of developmental and reproductive impacts of drug/chemical exposures; (2) that novel in silico platforms with high-throughput screening (HTS) data, biologically-inspired computational models of

  14. Assessment of skills using a virtual reality temporal bone surgery simulator.

    Science.gov (United States)

    Linke, R; Leichtle, A; Sheikh, F; Schmidt, C; Frenzel, H; Graefe, H; Wollenberg, B; Meyer, J E

    2013-08-01

    Surgery on the temporal bone is technically challenging due to its complex anatomy. Precise anatomical dissection of the human temporal bone is essential and is fundamental for middle ear surgery. We assessed the possible application of a virtual reality temporal bone surgery simulator to the education of ear surgeons. Seventeen ENT physicians with different levels of surgical training and 20 medical students performed an antrotomy with a computer-based virtual temporal bone surgery simulator. The ease, accuracy and timing of the simulated temporal bone surgery were assessed using the automatic assessment software provided by the simulator device and additionally with a modified Final Product Analysis Scale. Trained ENT surgeons, physicians without temporal bone surgical training and medical students were all able to perform the antrotomy. However, the highly trained ENT surgeons were able to complete the surgery in approximately half the time, with better handling and accuracy as assessed by the significant reduction in injury to important middle ear structures. Trained ENT surgeons achieved significantly higher scores using both dissection analysis methods. Surprisingly, there were no significant differences in the results between medical students and physicians without experience in ear surgery. The virtual temporal bone training system can stratify users of known levels of experience. This system can be used not only to improve the surgical skills of trained ENT surgeons for more successful and injury-free surgeries, but also to train inexperienced physicians/medical students in developing their surgical skills for the ear.

  15. Purex optimization by computer simulation

    International Nuclear Information System (INIS)

    Campbell, T.G.; McKibben, J.M.

    1980-08-01

    For the past 2 years computer simulation has been used to study the performance of several solvent extraction banks in the Purex facility at the Savannah River Plant in Aiken, South Carolina. Individual process parameters were varied about their normal base case values to determine their individual effects on concentration profiles and end-stream compositions. The data are presented in graphical form to show the extent to which product losses, decontamination factors, solvent extraction bank inventories of fissile materials, and other key properties are affected by process changes. Presented in this way, the data are useful for adapting flowsheet conditions to a particular feed material or product specification, and for evaluating nuclear safety as related to bank inventories

  16. Computer simulation of chemical nucleation

    International Nuclear Information System (INIS)

    Turner, J.S.

    1979-01-01

    The problem of nucleation at chemical instabilities is investigated by means of microscopic computer simulation. The first-order transition of interest involves a new kind of nucleation arising from chemical transformations rather than physical forces. Here it is the chemical state of matter, and not matter itself, which is spatially localized to form the nucleus for transition between different chemical states. First, the concepts of chemical instability, nonequilibrium phase transition, and dissipative structure are reviewed briefly. Then recently developed methods of reactive molecular dynamics are used to study chemical nucleation in a simple model chemical reactions. Finally, the connection of these studies to nucleation and condensation processes involving physical and chemical interactions is explored. (orig.)

  17. Computer-assisted preoperative simulation for positioning of plate fixation in Lefort I osteotomy: A case report

    Directory of Open Access Journals (Sweden)

    Hideyuki Suenaga

    2016-06-01

    Full Text Available Computed tomography images are used for three-dimensional planning in orthognathic surgery. This facilitates the actual surgery by simulating the surgical scenario. We performed a computer-assisted virtual orthognathic surgical procedure using optically scanned three-dimensional (3D data and real computed tomography data on a personal computer. It helped maxillary bone movement and positioning and the titanium plate temporary fixation and positioning. This simulated the surgical procedure, which made the procedure easy, and we could perform precise actual surgery and could forecast the postsurgery outcome. This simulation method promises great potential in orthognathic surgery to help surgeons plan and perform operative procedures more precisely.

  18. Discrete Event Simulation Computers can be used to simulate the ...

    Indian Academy of Sciences (India)

    IAS Admin

    people who use computers every moment of their waking lives, others even ... How is discrete event simulation different from other kinds of simulation? ... time, energy consumption .... Schedule the CustomerDeparture event for this customer.

  19. Graphic and haptic simulation system for virtual laparoscopic rectum surgery.

    Science.gov (United States)

    Pan, Jun J; Chang, Jian; Yang, Xiaosong; Zhang, Jian J; Qureshi, Tahseen; Howell, Robert; Hickish, Tamas

    2011-09-01

    Medical simulators with vision and haptic feedback techniques offer a cost-effective and efficient alternative to the traditional medical trainings. They have been used to train doctors in many specialties of medicine, allowing tasks to be practised in a safe and repetitive manner. This paper describes a virtual-reality (VR) system which will help to influence surgeons' learning curves in the technically challenging field of laparoscopic surgery of the rectum. Data from MRI of the rectum and real operation videos are used to construct the virtual models. A haptic force filter based on radial basis functions is designed to offer realistic and smooth force feedback. To handle collision detection efficiently, a hybrid model is presented to compute the deformation of intestines. Finally, a real-time cutting technique based on mesh is employed to represent the incision operation. Despite numerous research efforts, fast and realistic solutions of soft tissues with large deformation, such as intestines, prove extremely challenging. This paper introduces our latest contribution to this endeavour. With this system, the user can haptically operate with the virtual rectum and simultaneously watch the soft tissue deformation. Our system has been tested by colorectal surgeons who believe that the simulated tactile and visual feedbacks are realistic. It could replace the traditional training process and effectively transfer surgical skills to novices. Copyright © 2011 John Wiley & Sons, Ltd.

  20. Framework for utilizing computational devices within simulation

    Directory of Open Access Journals (Sweden)

    Miroslav Mintál

    2013-12-01

    Full Text Available Nowadays there exist several frameworks to utilize a computation power of graphics cards and other computational devices such as FPGA, ARM and multi-core processors. The best known are either low-level and need a lot of controlling code or are bounded only to special graphic cards. Furthermore there exist more specialized frameworks, mainly aimed to the mathematic field. Described framework is adjusted to use in a multi-agent simulations. Here it provides an option to accelerate computations when preparing simulation and mainly to accelerate a computation of simulation itself.

  1. Distributed simulation of large computer systems

    International Nuclear Information System (INIS)

    Marzolla, M.

    2001-01-01

    Sequential simulation of large complex physical systems is often regarded as a computationally expensive task. In order to speed-up complex discrete-event simulations, the paradigm of Parallel and Distributed Discrete Event Simulation (PDES) has been introduced since the late 70s. The authors analyze the applicability of PDES to the modeling and analysis of large computer system; such systems are increasingly common in the area of High Energy and Nuclear Physics, because many modern experiments make use of large 'compute farms'. Some feasibility tests have been performed on a prototype distributed simulator

  2. Fluid structure interaction simulations of the upper airway in obstructive sleep apnea patients before and after maxillomandibular advancement surgery.

    Science.gov (United States)

    Chang, Kwang K; Kim, Ki Beom; McQuilling, Mark W; Movahed, Reza

    2018-06-01

    The purpose of this study was to analyze pharyngeal airflow using both computational fluid dynamics (CFD) and fluid structure interactions (FSI) in obstructive sleep apnea patients before and after maxillomandibular advancement (MMA) surgery. The airflow characteristics before and after surgery were compared with both CFD and FSI. In addition, the presurgery and postsurgery deformations of the airway were evaluated using FSI. Digitized pharyngeal airway models of 2 obstructive sleep apnea patients were generated from cone-beam computed tomography scans before and after MMA surgery. CFD and FSI were used to evaluate the pharyngeal airflow at a maximum inspiration rate of 166 ml per second. Standard steady-state numeric formulations were used for airflow simulations. Airway volume increased, pressure drop decreased, maximum airflow velocity decreased, and airway resistance dropped for both patients after the MMA surgery. These findings occurred in both the CFD and FSI simulations. The FSI simulations showed an area of marked airway deformation in both patients before surgery, but this deformation was negligible after surgery for both patients. Both CFD and FSI simulations produced airflow results that indicated less effort was needed to breathe after MMA surgery. The FSI simulations demonstrated a substantial decrease in airway deformation after surgery. These beneficial changes positively correlated with the large improvements in polysomnography outcomes after MMA surgery. Copyright © 2018 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

  3. Computed tomographic evaluation of realignment surgery for patellar subluxation

    International Nuclear Information System (INIS)

    Inoue, Masahiro; Shino, Konsei; Maeda, Akira; Nakata, Ken; Ono, Hiroo.

    1994-01-01

    Forty-two patients with patellar subluxation underwent realignment surgery of the knee extensor mechanism. The surgery included, lateral release, advancement and reefing of the vastus medialis and the medial capsule and tibial tubercle transfer (Elmslie-Trillat procedure). The effect of surgery was evaluated using computed tomograms of the pre- and post-operative knees at 0, 15, 30 and 45 degrees of knee flexion. The degree of patellofemoral incongruence on CT was expressed using two parameters of patellar tilt and patellar shift. Thirty-three volunteers without any patello-femoral symptoms served as controls. Postoperatively both the patellar tilt and the patellar shift improved significantly. The average patellar tilt and the patellar shift of the patient group at 45 degrees were comparable with those of controls. However, it was found by CT that the realignment surgery was less effective between 0 and 30 degrees of knee flexion. (author)

  4. Computed tomographic evaluation of realignment surgery for patellar subluxation

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Masahiro (Kansai Rosai Hospital, Amagasaki (Japan)); Shino, Konsei; Maeda, Akira; Nakata, Ken; Ono, Hiroo

    1994-01-01

    Forty-two patients with patellar subluxation underwent realignment surgery of the knee extensor mechanism. The surgery included, lateral release, advancement and reefing of the vastus medialis and the medial capsule and tibial tubercle transfer (Elmslie-Trillat procedure). The effect of surgery was evaluated using computed tomograms of the pre- and post-operative knees at 0, 15, 30 and 45 degrees of knee flexion. The degree of patellofemoral incongruence on CT was expressed using two parameters of patellar tilt and patellar shift. Thirty-three volunteers without any patello-femoral symptoms served as controls. Postoperatively both the patellar tilt and the patellar shift improved significantly. The average patellar tilt and the patellar shift of the patient group at 45 degrees were comparable with those of controls. However, it was found by CT that the realignment surgery was less effective between 0 and 30 degrees of knee flexion. (author).

  5. Analyzing Robotic Kinematics Via Computed Simulations

    Science.gov (United States)

    Carnahan, Timothy M.

    1992-01-01

    Computing system assists in evaluation of kinematics of conceptual robot. Displays positions and motions of robotic manipulator within work cell. Also displays interactions between robotic manipulator and other objects. Results of simulation displayed on graphical computer workstation. System includes both off-the-shelf software originally developed for automotive industry and specially developed software. Simulation system also used to design human-equivalent hand, to model optical train in infrared system, and to develop graphical interface for teleoperator simulation system.

  6. Towards ubiquitous access of computer-assisted surgery systems.

    Science.gov (United States)

    Liu, Hui; Lufei, Hanping; Shi, Weishong; Chaudhary, Vipin

    2006-01-01

    Traditional stand-alone computer-assisted surgery (CAS) systems impede the ubiquitous and simultaneous access by multiple users. With advances in computing and networking technologies, ubiquitous access to CAS systems becomes possible and promising. Based on our preliminary work, CASMIL, a stand-alone CAS server developed at Wayne State University, we propose a novel mobile CAS system, UbiCAS, which allows surgeons to retrieve, review and interpret multimodal medical images, and to perform some critical neurosurgical procedures on heterogeneous devices from anywhere at anytime. Furthermore, various optimization techniques, including caching, prefetching, pseudo-streaming-model, and compression, are used to guarantee the QoS of the UbiCAS system. UbiCAS enables doctors at remote locations to actively participate remote surgeries, share patient information in real time before, during, and after the surgery.

  7. Computer Simulation of a Hardwood Processing Plant

    Science.gov (United States)

    D. Earl Kline; Philip A. Araman

    1990-01-01

    The overall purpose of this paper is to introduce computer simulation as a decision support tool that can be used to provide managers with timely information. A simulation/animation modeling procedure is demonstrated for wood products manufacuring systems. Simulation modeling techniques are used to assist in identifying and solving problems. Animation is used for...

  8. Computer Based Modelling and Simulation

    Indian Academy of Sciences (India)

    GENERAL I ARTICLE. Computer Based ... universities, and later did system analysis, ... sonal computers (PC) and low cost software packages and tools. They can serve as useful learning experience through student projects. Models are .... Let us consider a numerical example: to calculate the velocity of a trainer aircraft ...

  9. Oral and maxillofacial surgery with computer-assisted navigation system.

    Science.gov (United States)

    Kawachi, Homare; Kawachi, Yasuyuki; Ikeda, Chihaya; Takagi, Ryo; Katakura, Akira; Shibahara, Takahiko

    2010-01-01

    Intraoperative computer-assisted navigation has gained acceptance in maxillofacial surgery with applications in an increasing number of indications. We adapted a commercially available wireless passive marker system which allows calibration and tracking of virtually every instrument in maxillofacial surgery. Virtual computer-generated anatomical structures are displayed intraoperatively in a semi-immersive head-up display. Continuous observation of the operating field facilitated by computer assistance enables surgical navigation in accordance with the physician's preoperative plans. This case report documents the potential for augmented visualization concepts in surgical resection of tumors in the oral and maxillofacial region. We report a case of T3N2bM0 carcinoma of the maxillary gingival which was surgically resected with the assistance of the Stryker Navigation Cart System. This system was found to be useful in assisting preoperative planning and intraoperative monitoring.

  10. Computer Simulations of Lipid Bilayers and Proteins

    DEFF Research Database (Denmark)

    Sonne, Jacob

    2006-01-01

    The importance of computer simulations in lipid bilayer research has become more prominent for the last couple of decades and as computers get even faster, simulations will play an increasingly important part of understanding the processes that take place in and across cell membranes. This thesis...... entitled Computer simulations of lipid bilayers and proteins describes two molecular dynamics (MD) simulation studies of pure lipid bilayers as well as a study of a transmembrane protein embedded in a lipid bilayer matrix. Below follows a brief overview of the thesis. Chapter 1. This chapter is a short...... in the succeeding chapters is presented. Details on system setups, simulation parameters and other technicalities can be found in the relevant chapters. Chapter 3, DPPC lipid parameters: The quality of MD simulations is intimately dependent on the empirical potential energy function and its parameters, i...

  11. Filtration theory using computer simulations

    Energy Technology Data Exchange (ETDEWEB)

    Bergman, W.; Corey, I. [Lawrence Livermore National Lab., CA (United States)

    1997-08-01

    We have used commercially available fluid dynamics codes based on Navier-Stokes theory and the Langevin particle equation of motion to compute the particle capture efficiency and pressure drop through selected two- and three-dimensional fiber arrays. The approach we used was to first compute the air velocity vector field throughout a defined region containing the fiber matrix. The particle capture in the fiber matrix is then computed by superimposing the Langevin particle equation of motion over the flow velocity field. Using the Langevin equation combines the particle Brownian motion, inertia and interception mechanisms in a single equation. In contrast, most previous investigations treat the different capture mechanisms separately. We have computed the particle capture efficiency and the pressure drop through one, 2-D and two, 3-D fiber matrix elements. 5 refs., 11 figs.

  12. Virtual reality simulator for vitreoretinal surgery using integrated OCT data

    Directory of Open Access Journals (Sweden)

    Kozak I

    2014-03-01

    Full Text Available Igor Kozak,1 Pat Banerjee,2 Jia Luo,2 Cristian Luciano21King Khaled Eye Specialist Hospital, Vitreoretinal Division, Riyadh, Kingdom of Saudi Arabia; 2College of Engineering, University of Illinois at Chicago, Chicago, IL, USAAbstract: Operative practice using surgical simulators has become a part of training in many surgical specialties, including ophthalmology. We introduce a virtual reality retina surgery simulator capable of integrating optical coherence tomography (OCT scans from real patients for practicing vitreoretinal surgery using different pathologic scenarios.Keywords: optical coherence tomography

  13. Computer simulation of bounded plasmas

    International Nuclear Information System (INIS)

    Lawson, W.S.

    1987-01-01

    The problems of simulating a one-dimensional bounded plasma system using particles in a gridded space are systematically explored and solutions to them are given. Such problems include the injection of particles at the boundaries, the solution of Poisson's equation, and the inclusion of an external circuit between the confining boundaries. A recently discovered artificial cooling effect is explained as being a side-effect of quiet injection, and its potential for causing serious but subtle errors in bounded simulation is noted. The methods described in the first part of the thesis are then applied to the simulation of an extension of the Pierce diode problem, specifically a Pierce diode modified by an external circuit between the electrodes. The results of these simulations agree to high accuracy with theory when a theory exists, and also show some interesting chaotic behavior in certain parameter regimes. The chaotic behavior is described in detail

  14. Simulation-based summative assessments in surgery.

    Science.gov (United States)

    Szasz, Peter; Grantcharov, Teodor P; Sweet, Robert M; Korndorffer, James R; Pedowitz, Robert A; Roberts, Patricia L; Sachdeva, Ajit K

    2016-09-01

    The American College of Surgeons-Accredited Education Institutes (ACS-AEI) Consortium aims to enhance patient safety and advance surgical education through the use of cutting-edge simulation-based training and assessment methods. The annual ACS-AEI Consortium meeting provides a forum to discuss the latest simulation-based training and assessment methods and includes special panel presentations on key topics. During the 8th annual Consortium, there was a panel presentation on simulation-based summative assessments, during which experiences from across surgical disciplines were presented. The formal presentations were followed by a robust discussion between the conference attendees and the panelists. This report summarizes the panelists' presentations and their ensuing discussion with attendees. The focus of this report is on the basis for and advances in simulation-based summative assessments, the current practices employed across various surgical disciplines, and future directions that may be pursued by the ACS-AEI Consortium. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. 9th Asian Conference on Computer-Aided Surgery

    CERN Document Server

    2016-01-01

    This book presents the latest research advances in the theory, design, control, and application of robot systems intended for a variety of purposes such as manipulation, manufacturing, automation, surgery, locomotion, and biomechanics. Several chapters deal with fundamental kinematics in nature, including synthesis, calibration, redundancy, force control, dexterity, inverse and forward kinematics, kinematic singularities, and over-constrained systems. This book is a compilation of the extended versions of the very best papers selected from the many that were presented at the Asian Conference on Computer-Aided Surgery held September 16–18, 2013, in Tokyo, Japan (ACCAS 2013).

  16. Validation of a Novel Virtual Reality Simulator for Robotic Surgery

    Directory of Open Access Journals (Sweden)

    Henk W. R. Schreuder

    2014-01-01

    Full Text Available Objective. With the increase in robotic-assisted laparoscopic surgery there is a concomitant rising demand for training methods. The objective was to establish face and construct validity of a novel virtual reality simulator (dV-Trainer, Mimic Technologies, Seattle, WA for the use in training of robot-assisted surgery. Methods. A comparative cohort study was performed. Participants (n=42 were divided into three groups according to their robotic experience. To determine construct validity, participants performed three different exercises twice. Performance parameters were measured. To determine face validity, participants filled in a questionnaire after completion of the exercises. Results. Experts outperformed novices in most of the measured parameters. The most discriminative parameters were “time to complete” and “economy of motion” (P<0.001. The training capacity of the simulator was rated 4.6 ± 0.5 SD on a 5-point Likert scale. The realism of the simulator in general, visual graphics, movements of instruments, interaction with objects, and the depth perception were all rated as being realistic. The simulator is considered to be a very useful training tool for residents and medical specialist starting with robotic surgery. Conclusions. Face and construct validity for the dV-Trainer could be established. The virtual reality simulator is a useful tool for training robotic surgery.

  17. Early orthognathic surgery with three-dimensional image simulation during presurgical orthodontics in adults.

    Science.gov (United States)

    Kang, Sang-Hoon; Kim, Moon-Key; Park, Sun-Yeon; Lee, Ji-Yeon; Park, Wonse; Lee, Sang-Hwy

    2011-03-01

    To correct dentofacial deformities, three-dimensional skeletal analysis and computerized orthognathic surgery simulation are used to facilitate accurate diagnoses and surgical plans. Computed tomography imaging of dental occlusion can inform three-dimensional facial analyses and orthognathic surgical simulations. Furthermore, three-dimensional laser scans of a cast model of the predetermined postoperative dental occlusion can be used to increase the accuracy of the preoperative surgical simulation. In this study, we prepared cast models of planned postoperative dental occlusions from 12 patients diagnosed with skeletal class III malocclusions with mandibular prognathism and facial asymmetry that had planned to undergo bimaxillary orthognathic surgery during preoperative orthodontic treatment. The data from three-dimensional laser scans of the cast models were used in three-dimensional surgical simulations. Early orthognathic surgeries were performed based on three-dimensional image simulations using the cast images in several presurgical orthodontic states in which teeth alignment, leveling, and space closure were incomplete. After postoperative orthodontic treatments, intraoral examinations revealed that no patient had a posterior open bite or space. The two-dimensional and three-dimensional skeletal analyses showed that no mandibular deviations occurred between the immediate and final postoperative states of orthodontic treatment. These results showed that early orthognathic surgery with three-dimensional computerized simulations based on cast models of predetermined postoperative dental occlusions could provide early correction of facial deformities and improved efficacy of preoperative orthodontic treatment. This approach can reduce the decompensation treatment period of the presurgical orthodontics and contribute to efficient postoperative orthodontic treatments.

  18. Quantum simulations with noisy quantum computers

    Science.gov (United States)

    Gambetta, Jay

    Quantum computing is a new computational paradigm that is expected to lie beyond the standard model of computation. This implies a quantum computer can solve problems that can't be solved by a conventional computer with tractable overhead. To fully harness this power we need a universal fault-tolerant quantum computer. However the overhead in building such a machine is high and a full solution appears to be many years away. Nevertheless, we believe that we can build machines in the near term that cannot be emulated by a conventional computer. It is then interesting to ask what these can be used for. In this talk we will present our advances in simulating complex quantum systems with noisy quantum computers. We will show experimental implementations of this on some small quantum computers.

  19. Computer simulations of anomalous transport

    International Nuclear Information System (INIS)

    Lee, W.W.; Okuda, H.

    1980-07-01

    Numerical plasma simulations have been carried out to study: (1) the turbulent spectrum and anomalous plasma transport associated with a steady state electrostatic drift turbulence; and (2) the anomalous energy transport of electrons due to shear-Alfven waves in a finite-β plasma. For the simulation of the steady state drift turbulence, it is observed that, in the absence of magnetic shear, the turbulence is quenched to a low level when the rotational transform is a rational number, while the turbulent level remains high for an irrational rotational transform

  20. Prevailing Trends in Haptic Feedback Simulation for Minimally Invasive Surgery.

    Science.gov (United States)

    Pinzon, David; Byrns, Simon; Zheng, Bin

    2016-08-01

    Background The amount of direct hand-tool-tissue interaction and feedback in minimally invasive surgery varies from being attenuated in laparoscopy to being completely absent in robotic minimally invasive surgery. The role of haptic feedback during surgical skill acquisition and its emphasis in training have been a constant source of controversy. This review discusses the major developments in haptic simulation as they relate to surgical performance and the current research questions that remain unanswered. Search Strategy An in-depth review of the literature was performed using PubMed. Results A total of 198 abstracts were returned based on our search criteria. Three major areas of research were identified, including advancements in 1 of the 4 components of haptic systems, evaluating the effectiveness of haptic integration in simulators, and improvements to haptic feedback in robotic surgery. Conclusions Force feedback is the best method for tissue identification in minimally invasive surgery and haptic feedback provides the greatest benefit to surgical novices in the early stages of their training. New technology has improved our ability to capture, playback and enhance to utility of haptic cues in simulated surgery. Future research should focus on deciphering how haptic training in surgical education can increase performance, safety, and improve training efficiency. © The Author(s) 2016.

  1. Computer simulations of collisionless shock waves

    International Nuclear Information System (INIS)

    Leroy, M.M.

    1984-01-01

    A review of the contributions of particle computer simulations to the understanding of the physics of magnetic shock waves in collisionless plasmas is presented. The emphasis is on the relation between the computer simulation results, spacecraft observations of shocks in space, and related theories, rather than on technical aspects of the numerics. It is shown that much has been learned from the comparison of ISEE spacecraft observations of the terrestrial bow shock and particle computer simulations concerning the quasi-perpendicular, supercritical shock (ion scale structure, ion reflection mechanism and ultimate dissipation processes). Particle computer simulations have also had an appreciable prospective role in the investigation of the physics of quasi-parallel shocks, about which still little is known observationally. Moreover, these numerical techniques have helped to clarify the process of suprathermal ion rejection by the shock into the foreshock, and the subsequent evolution of the ions in the foreshock. 95 references

  2. Augmented Reality Simulations on Handheld Computers

    Science.gov (United States)

    Squire, Kurt; Klopfer, Eric

    2007-01-01

    Advancements in handheld computing, particularly its portability, social interactivity, context sensitivity, connectivity, and individuality, open new opportunities for immersive learning environments. This article articulates the pedagogical potential of augmented reality simulations in environmental engineering education by immersing students in…

  3. Computer Simulation in Information and Communication Engineering

    CERN Multimedia

    Anton Topurov

    2005-01-01

    CSICE'05 Sofia, Bulgaria 20th - 22nd October, 2005 On behalf of the International Scientific Committee, we would like to invite you all to Sofia, the capital city of Bulgaria, to the International Conference in Computer Simulation in Information and Communication Engineering CSICE'05. The Conference is aimed at facilitating the exchange of experience in the field of computer simulation gained not only in traditional fields (Communications, Electronics, Physics...) but also in the areas of biomedical engineering, environment, industrial design, etc. The objective of the Conference is to bring together lectures, researchers and practitioners from different countries, working in the fields of computer simulation in information engineering, in order to exchange information and bring new contribution to this important field of engineering design and education. The Conference will bring you the latest ideas and development of the tools for computer simulation directly from their inventors. Contribution describ...

  4. Computer Simulations, Disclosure and Duty of Care

    Directory of Open Access Journals (Sweden)

    John Barlow

    2006-05-01

    Full Text Available Computer simulations provide cost effective methods for manipulating and modeling 'reality'. However they are not real. They are imitations of a system or event, real or fabricated, and as such mimic, duplicate or represent that system or event. The degree to which a computer simulation aligns with and reproduces the ‘reality’ of the system or event it attempts to mimic or duplicate depends upon many factors including the efficiency of the simulation algorithm, the processing power of the computer hardware used to run the simulation model, and the expertise, assumptions and prejudices of those concerned with designing, implementing and interpreting the simulation output. Computer simulations in particular are increasingly replacing physical experimentation in many disciplines, and as a consequence, are used to underpin quite significant decision-making which may impact on ‘innocent’ third parties. In this context, this paper examines two interrelated issues: Firstly, how much and what kind of information should a simulation builder be required to disclose to potential users of the simulation? Secondly, what are the implications for a decision-maker who acts on the basis of their interpretation of a simulation output without any reference to its veracity, which may in turn comprise the safety of other parties?

  5. Computer Based Modelling and Simulation

    Indian Academy of Sciences (India)

    where x increases from zero to N, the saturation value. Box 1. Matrix Meth- ... such as Laplace transforms and non-linear differential equa- tions with .... atomic bomb project in the. US in the early ... his work on game theory and computers.

  6. Virtual reality simulator for vitreoretinal surgery using integrated OCT data

    OpenAIRE

    Kozak, Igor; Banerjee,Pat; Luo,Jia; Luciano,Cristian

    2014-01-01

    Igor Kozak,1 Pat Banerjee,2 Jia Luo,2 Cristian Luciano21King Khaled Eye Specialist Hospital, Vitreoretinal Division, Riyadh, Kingdom of Saudi Arabia; 2College of Engineering, University of Illinois at Chicago, Chicago, IL, USAAbstract: Operative practice using surgical simulators has become a part of training in many surgical specialties, including ophthalmology. We introduce a virtual reality retina surgery simulator capable of integrating optical coherence tomography (OCT) scans from real p...

  7. Validation of a novel virtual reality simulator for robotic surgery

    NARCIS (Netherlands)

    Schreuder, Henk W. R.; Persson, Jan E. U.; Wolswijk, Richard G. H.; Ihse, Ingmar; Schijven, Marlies P.; Verheijen, René H. M.

    2014-01-01

    With the increase in robotic-assisted laparoscopic surgery there is a concomitant rising demand for training methods. The objective was to establish face and construct validity of a novel virtual reality simulator (dV-Trainer, Mimic Technologies, Seattle, WA) for the use in training of

  8. [Guided maxillofacial surgery: Simulation and surgery aided by stereolithographic guides and custom-made miniplates.

    Science.gov (United States)

    Philippe, B

    2013-08-05

    We present a new model of guided surgery, exclusively using computer assistance, from the preoperative planning of osteotomies to the actual surgery with the aid of stereolithographic cutting guides and osteosynthetic miniplates designed and made preoperatively, using custom-made titanium miniplates thanks to direct metal laser sintering. We describe the principles that guide the designing and industrial manufacturing of this new type of osteosynthesis miniplates. The surgical procedure is described step-by-step using several representative cases of dento-maxillofacial dysmorphosis. The encouraging short-term results demonstrate the wide range of application of this new technology for cranio-maxillofacial surgery, whatever the type of osteotomy performed, and for plastic reconstructive surgery. Copyright © 2013. Published by Elsevier Masson SAS.

  9. REACTOR: a computer simulation for schools

    International Nuclear Information System (INIS)

    Squires, D.

    1985-01-01

    The paper concerns computer simulation of the operation of a nuclear reactor, for use in schools. The project was commissioned by UKAEA, and carried out by the Computers in the Curriculum Project, Chelsea College. The program, for an advanced gas cooled reactor, is briefly described. (U.K.)

  10. Predicting Surgery Targets in Temporal Lobe Epilepsy through Structural Connectome Based Simulations.

    Directory of Open Access Journals (Sweden)

    Frances Hutchings

    2015-12-01

    Full Text Available Temporal lobe epilepsy (TLE is a prevalent neurological disorder resulting in disruptive seizures. In the case of drug resistant epilepsy resective surgery is often considered. This is a procedure hampered by unpredictable success rates, with many patients continuing to have seizures even after surgery. In this study we apply a computational model of epilepsy to patient specific structural connectivity derived from diffusion tensor imaging (DTI of 22 individuals with left TLE and 39 healthy controls. We validate the model by examining patient-control differences in simulated seizure onset time and network location. We then investigate the potential of the model for surgery prediction by performing in silico surgical resections, removing nodes from patient networks and comparing seizure likelihood post-surgery to pre-surgery simulations. We find that, first, patients tend to transit from non-epileptic to epileptic states more often than controls in the model. Second, regions in the left hemisphere (particularly within temporal and subcortical regions that are known to be involved in TLE are the most frequent starting points for seizures in patients in the model. In addition, our analysis also implicates regions in the contralateral and frontal locations which may play a role in seizure spreading or surgery resistance. Finally, the model predicts that patient-specific surgery (resection areas chosen on an individual, model-prompted, basis and not following a predefined procedure may lead to better outcomes than the currently used routine clinical procedure. Taken together this work provides a first step towards patient specific computational modelling of epilepsy surgery in order to inform treatment strategies in individuals.

  11. Soft Tissue Biomechanical Modeling for Computer Assisted Surgery

    CERN Document Server

    2012-01-01

      This volume focuses on the biomechanical modeling of biological tissues in the context of Computer Assisted Surgery (CAS). More specifically, deformable soft tissues are addressed since they are the subject of the most recent developments in this field. The pioneering works on this CAS topic date from the 1980's, with applications in orthopaedics and biomechanical models of bones. More recently, however, biomechanical models of soft tissues have been proposed since most of the human body is made of soft organs that can be deformed by the surgical gesture. Such models are much more complicated to handle since the tissues can be subject to large deformations (non-linear geometrical framework) as well as complex stress/strain relationships (non-linear mechanical framework). Part 1 of the volume presents biomechanical models that have been developed in a CAS context and used during surgery. This is particularly new since most of the soft tissues models already proposed concern Computer Assisted Planning, with ...

  12. Learning and instruction with computer simulations

    NARCIS (Netherlands)

    de Jong, Anthonius J.M.

    1991-01-01

    The present volume presents the results of an inventory of elements of such a computer learning environment. This inventory was conducted within a DELTA project called SIMULATE. In the project a learning environment that provides intelligent support to learners and that has a simulation as its

  13. Salesperson Ethics: An Interactive Computer Simulation

    Science.gov (United States)

    Castleberry, Stephen

    2014-01-01

    A new interactive computer simulation designed to teach sales ethics is described. Simulation learner objectives include gaining a better understanding of legal issues in selling; realizing that ethical dilemmas do arise in selling; realizing the need to be honest when selling; seeing that there are conflicting demands from a salesperson's…

  14. Slab cooling system design using computer simulation

    NARCIS (Netherlands)

    Lain, M.; Zmrhal, V.; Drkal, F.; Hensen, J.L.M.

    2007-01-01

    For a new technical library building in Prague computer simulations were carried out to help design of slab cooling system and optimize capacity of chillers. In the paper is presented concept of new technical library HVAC system, the model of the building, results of the energy simulations for

  15. Simulations of Probabilities for Quantum Computing

    Science.gov (United States)

    Zak, M.

    1996-01-01

    It has been demonstrated that classical probabilities, and in particular, probabilistic Turing machine, can be simulated by combining chaos and non-LIpschitz dynamics, without utilization of any man-made devices (such as random number generators). Self-organizing properties of systems coupling simulated and calculated probabilities and their link to quantum computations are discussed.

  16. Computer simulations applied in materials

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-07-01

    This workshop takes stock of the simulation methods applied to nuclear materials and discusses the conditions in which these methods can predict physical results when no experimental data are available. The main topic concerns the radiation effects in oxides and includes also the behaviour of fission products in ceramics, the diffusion and segregation phenomena and the thermodynamical properties under irradiation. This document brings together a report of the previous 2002 workshop and the transparencies of 12 presentations among the 15 given at the workshop: accommodation of uranium and plutonium in pyrochlores; radiation effects in La{sub 2}Zr{sub 2}O{sub 7} pyrochlores; first principle calculations of defects formation energies in the Y{sub 2}(Ti,Sn,Zr){sub 2}O{sub 7} pyrochlore system; an approximate approach to predicting radiation tolerant materials; molecular dynamics study of the structural effects of displacement cascades in UO{sub 2}; composition defect maps for A{sup 3+}B{sup 3+}O{sub 3} perovskites; NMR characterization of radiation damaged materials: using simulation to interpret the data; local structure in damaged zircon: a first principle study; simulation studies on SiC; insertion and diffusion of He in 3C-SiC; a review of helium in silica; self-trapped holes in amorphous silicon dioxide: their short-range structure revealed from electron spin resonance and optical measurements and opportunities for inferring intermediate range structure by theoretical modelling. (J.S.)

  17. Computational simulation of radiographic film

    International Nuclear Information System (INIS)

    Goncalves, Elicardo A. de S.; Santos, Marcio H. dos; Anjos, Marcelino J.; Oliveira, Luis F. de

    2013-01-01

    The composition of a radiographic film gives its values of speed, spatial resolution and base density. The technical knowledge allows to predict how a film with a known composition works, and simulate how this film will work with changes in composition and exposure. In this paper, characterization of films composed by different emulsions was realized, in a way to know the characteristic curve, and to study how the format, organization and concentration of silver salt crystals set the radiographic film images.This work aims to increase an existing simulator, where parallel programming was used to simulate X-ray fluorescence processes. The setup of source and X-ray interactions with objects stills the same, and the detector constructed in this work was placed to form images. At first, considering the approach that the film is a square matrix where each element has a specific quantity of silver grains, that each grain fills a specific area, and that each interaction to radiation transforms a salt silver grain in to metallic silver grain (black grain), we have a blackening standard, and it should show how is the behavior of a optic density in a specific area of the film. Each matrix element has a degree of blackening, and it is proportional to the black grains area. (author)

  18. Computer simulations applied in materials

    International Nuclear Information System (INIS)

    2003-01-01

    This workshop takes stock of the simulation methods applied to nuclear materials and discusses the conditions in which these methods can predict physical results when no experimental data are available. The main topic concerns the radiation effects in oxides and includes also the behaviour of fission products in ceramics, the diffusion and segregation phenomena and the thermodynamical properties under irradiation. This document brings together a report of the previous 2002 workshop and the transparencies of 12 presentations among the 15 given at the workshop: accommodation of uranium and plutonium in pyrochlores; radiation effects in La 2 Zr 2 O 7 pyrochlores; first principle calculations of defects formation energies in the Y 2 (Ti,Sn,Zr) 2 O 7 pyrochlore system; an approximate approach to predicting radiation tolerant materials; molecular dynamics study of the structural effects of displacement cascades in UO 2 ; composition defect maps for A 3+ B 3+ O 3 perovskites; NMR characterization of radiation damaged materials: using simulation to interpret the data; local structure in damaged zircon: a first principle study; simulation studies on SiC; insertion and diffusion of He in 3C-SiC; a review of helium in silica; self-trapped holes in amorphous silicon dioxide: their short-range structure revealed from electron spin resonance and optical measurements and opportunities for inferring intermediate range structure by theoretical modelling. (J.S.)

  19. [Animal experimentation, computer simulation and surgical research].

    Science.gov (United States)

    Carpentier, Alain

    2009-11-01

    We live in a digital world In medicine, computers are providing new tools for data collection, imaging, and treatment. During research and development of complex technologies and devices such as artificial hearts, computer simulation can provide more reliable information than experimentation on large animals. In these specific settings, animal experimentation should serve more to validate computer models of complex devices than to demonstrate their reliability.

  20. Computer graphics in heat-transfer simulations

    International Nuclear Information System (INIS)

    Hamlin, G.A. Jr.

    1980-01-01

    Computer graphics can be very useful in the setup of heat transfer simulations and in the display of the results of such simulations. The potential use of recently available low-cost graphics devices in the setup of such simulations has not been fully exploited. Several types of graphics devices and their potential usefulness are discussed, and some configurations of graphics equipment are presented in the low-, medium-, and high-price ranges

  1. Computer simulation of gear tooth manufacturing processes

    Science.gov (United States)

    Mavriplis, Dimitri; Huston, Ronald L.

    1990-01-01

    The use of computer graphics to simulate gear tooth manufacturing procedures is discussed. An analytical basis for the simulation is established for spur gears. The simulation itself, however, is developed not only for spur gears, but for straight bevel gears as well. The applications of the developed procedure extend from the development of finite element models of heretofore intractable geometrical forms, to exploring the fabrication of nonstandard tooth forms.

  2. 3D printing to simulate laparoscopic choledochal surgery.

    Science.gov (United States)

    Burdall, Oliver C; Makin, Erica; Davenport, Mark; Ade-Ajayi, Niyi

    2016-05-01

    Laparoscopic simulation has transformed skills acquisition for many procedures. However, realistic nonbiological simulators for complex reconstructive surgery are rare. Life-like tactile feedback is particularly difficult to reproduce. Technological innovations may contribute novel solutions to these shortages. We describe a hybrid model, harnessing 3D technology to simulate laparoscopic choledochal surgery for the first time. Digital hepatic anatomy images and standard laparoscopic trainer dimensions were employed to create an entry level laparoscopic choledochal surgery model. The information was fed into a 3D systems project 660pro with visijet pxl core powder to create a free standing liver mold. This included a cuboid portal in which to slot disposable hybrid components representing hepatic and pancreatic ducts and choledochal cyst. The mold was used to create soft silicone replicas with T28 resin and T5 fast catalyst. The model was assessed at a national pediatric surgery training day. The 10 delegates that trialed the simulation felt that the tactile likeness was good (5.6/10±1.71, 10=like the real thing), was not too complex (6.2/10±1.35; where 1=too simple, 10=too complicated), and generally very useful (7.36/10±1.57, 10=invaluable). 100% stated that they felt they could reproduce this in their own centers, and 100% would recommend this simulation to colleagues. Though this first phase choledochal cyst excision simulation requires further development, 3D printing provides a useful means of creating specific and detailed simulations for rare and complex operations with huge potential for development. Copyright © 2016. Published by Elsevier Inc.

  3. Cluster computing software for GATE simulations

    International Nuclear Information System (INIS)

    Beenhouwer, Jan de; Staelens, Steven; Kruecker, Dirk; Ferrer, Ludovic; D'Asseler, Yves; Lemahieu, Ignace; Rannou, Fernando R.

    2007-01-01

    Geometry and tracking (GEANT4) is a Monte Carlo package designed for high energy physics experiments. It is used as the basis layer for Monte Carlo simulations of nuclear medicine acquisition systems in GEANT4 Application for Tomographic Emission (GATE). GATE allows the user to realistically model experiments using accurate physics models and time synchronization for detector movement through a script language contained in a macro file. The downside of this high accuracy is long computation time. This paper describes a platform independent computing approach for running GATE simulations on a cluster of computers in order to reduce the overall simulation time. Our software automatically creates fully resolved, nonparametrized macros accompanied with an on-the-fly generated cluster specific submit file used to launch the simulations. The scalability of GATE simulations on a cluster is investigated for two imaging modalities, positron emission tomography (PET) and single photon emission computed tomography (SPECT). Due to a higher sensitivity, PET simulations are characterized by relatively high data output rates that create rather large output files. SPECT simulations, on the other hand, have lower data output rates but require a long collimator setup time. Both of these characteristics hamper scalability as a function of the number of CPUs. The scalability of PET simulations is improved here by the development of a fast output merger. The scalability of SPECT simulations is improved by greatly reducing the collimator setup time. Accordingly, these two new developments result in higher scalability for both PET and SPECT simulations and reduce the computation time to more practical values

  4. Atomistic computer simulations a practical guide

    CERN Document Server

    Brazdova, Veronika

    2013-01-01

    Many books explain the theory of atomistic computer simulations; this book teaches you how to run them This introductory ""how to"" title enables readers to understand, plan, run, and analyze their own independent atomistic simulations, and decide which method to use and which questions to ask in their research project. It is written in a clear and precise language, focusing on a thorough understanding of the concepts behind the equations and how these are used in the simulations. As a result, readers will learn how to design the computational model and which parameters o

  5. Polymer Composites Corrosive Degradation: A Computational Simulation

    Science.gov (United States)

    Chamis, Christos C.; Minnetyan, Levon

    2007-01-01

    A computational simulation of polymer composites corrosive durability is presented. The corrosive environment is assumed to manage the polymer composite degradation on a ply-by-ply basis. The degradation is correlated with a measured pH factor and is represented by voids, temperature and moisture which vary parabolically for voids and linearly for temperature and moisture through the laminate thickness. The simulation is performed by a computational composite mechanics computer code which includes micro, macro, combined stress failure and laminate theories. This accounts for starting the simulation from constitutive material properties and up to the laminate scale which exposes the laminate to the corrosive environment. Results obtained for one laminate indicate that the ply-by-ply degradation degrades the laminate to the last one or the last several plies. Results also demonstrate that the simulation is applicable to other polymer composite systems as well.

  6. Computer Code for Nanostructure Simulation

    Science.gov (United States)

    Filikhin, Igor; Vlahovic, Branislav

    2009-01-01

    Due to their small size, nanostructures can have stress and thermal gradients that are larger than any macroscopic analogue. These gradients can lead to specific regions that are susceptible to failure via processes such as plastic deformation by dislocation emission, chemical debonding, and interfacial alloying. A program has been developed that rigorously simulates and predicts optoelectronic properties of nanostructures of virtually any geometrical complexity and material composition. It can be used in simulations of energy level structure, wave functions, density of states of spatially configured phonon-coupled electrons, excitons in quantum dots, quantum rings, quantum ring complexes, and more. The code can be used to calculate stress distributions and thermal transport properties for a variety of nanostructures and interfaces, transport and scattering at nanoscale interfaces and surfaces under various stress states, and alloy compositional gradients. The code allows users to perform modeling of charge transport processes through quantum-dot (QD) arrays as functions of inter-dot distance, array order versus disorder, QD orientation, shape, size, and chemical composition for applications in photovoltaics and physical properties of QD-based biochemical sensors. The code can be used to study the hot exciton formation/relation dynamics in arrays of QDs of different shapes and sizes at different temperatures. It also can be used to understand the relation among the deposition parameters and inherent stresses, strain deformation, heat flow, and failure of nanostructures.

  7. Creating science simulations through Computational Thinking Patterns

    Science.gov (United States)

    Basawapatna, Ashok Ram

    Computational thinking aims to outline fundamental skills from computer science that everyone should learn. As currently defined, with help from the National Science Foundation (NSF), these skills include problem formulation, logically organizing data, automating solutions through algorithmic thinking, and representing data through abstraction. One aim of the NSF is to integrate these and other computational thinking concepts into the classroom. End-user programming tools offer a unique opportunity to accomplish this goal. An end-user programming tool that allows students with little or no prior experience the ability to create simulations based on phenomena they see in-class could be a first step towards meeting most, if not all, of the above computational thinking goals. This thesis describes the creation, implementation and initial testing of a programming tool, called the Simulation Creation Toolkit, with which users apply high-level agent interactions called Computational Thinking Patterns (CTPs) to create simulations. Employing Computational Thinking Patterns obviates lower behavior-level programming and allows users to directly create agent interactions in a simulation by making an analogy with real world phenomena they are trying to represent. Data collected from 21 sixth grade students with no prior programming experience and 45 seventh grade students with minimal programming experience indicates that this is an effective first step towards enabling students to create simulations in the classroom environment. Furthermore, an analogical reasoning study that looked at how users might apply patterns to create simulations from high- level descriptions with little guidance shows promising results. These initial results indicate that the high level strategy employed by the Simulation Creation Toolkit is a promising strategy towards incorporating Computational Thinking concepts in the classroom environment.

  8. Computer simulation at high pressure

    International Nuclear Information System (INIS)

    Alder, B.J.

    1977-11-01

    The use of either the Monte Carlo or molecular dynamics method to generate equations-of-state data for various materials at high pressure is discussed. Particular emphasis is given to phase diagrams, such as the generation of various types of critical lines for mixtures, melting, structural and electronic transitions in solids, two-phase ionic fluid systems of astrophysical interest, as well as a brief aside of possible eutectic behavior in the interior of the earth. Then the application of the molecular dynamics method to predict transport coefficients and the neutron scattering function is discussed with a view as to what special features high pressure brings out. Lastly, an analysis by these computational methods of the measured intensity and frequency spectrum of depolarized light and also of the deviation of the dielectric measurements from the constancy of the Clausius--Mosotti function is given that leads to predictions of how the electronic structure of an atom distorts with pressure

  9. Computer simulation of defect cluster

    Energy Technology Data Exchange (ETDEWEB)

    Kuramoto, Eiichi [Kyushu Univ., Kasuga, Fukuoka (Japan). Research Inst. for Applied Mechanics

    1996-04-01

    In order to elucidate individual element process of various defects and defect clusters of used materials under irradiation environments, interatomic potential with reliability was investigated. And for comparison with experimental results, it is often required to adopt the temperature effect and to investigate in details mechanism of one dimensional motion of micro conversion loop and so forth using the molecular dynamic (MD) method. Furthermore, temperature effect is also supposed for stable structure of defects and defect clusters, and many problems relating to alloy element are also remained. And, simulation on photon life at the defects and defect clusters thought to be important under comparison with equipment can also be supposed an improvement of effectiveness due to relation to theses products. In this paper, some topics in such flow was extracted to explain them. In particular, future important problems will be potential preparation of alloy, structure, dynamic behavior and limited temperature of intralattice atomic cluster. (G.K.)

  10. Computational steering of GEM based detector simulations

    Science.gov (United States)

    Sheharyar, Ali; Bouhali, Othmane

    2017-10-01

    Gas based detector R&D relies heavily on full simulation of detectors and their optimization before final prototypes can be built and tested. These simulations in particular those with complex scenarios such as those involving high detector voltages or gas with larger gains are computationally intensive may take several days or weeks to complete. These long-running simulations usually run on the high-performance computers in batch mode. If the results lead to unexpected behavior, then the simulation might be rerun with different parameters. However, the simulations (or jobs) may have to wait in a queue until they get a chance to run again because the supercomputer is a shared resource that maintains a queue of other user programs as well and executes them as time and priorities permit. It may result in inefficient resource utilization and increase in the turnaround time for the scientific experiment. To overcome this issue, the monitoring of the behavior of a simulation, while it is running (or live), is essential. In this work, we employ the computational steering technique by coupling the detector simulations with a visualization package named VisIt to enable the exploration of the live data as it is produced by the simulation.

  11. Virtual reality simulators and training in laparoscopic surgery.

    Science.gov (United States)

    Yiannakopoulou, Eugenia; Nikiteas, Nikolaos; Perrea, Despina; Tsigris, Christos

    2015-01-01

    Virtual reality simulators provide basic skills training without supervision in a controlled environment, free of pressure of operating on patients. Skills obtained through virtual reality simulation training can be transferred on the operating room. However, relative evidence is limited with data available only for basic surgical skills and for laparoscopic cholecystectomy. No data exist on the effect of virtual reality simulation on performance on advanced surgical procedures. Evidence suggests that performance on virtual reality simulators reliably distinguishes experienced from novice surgeons Limited available data suggest that independent approach on virtual reality simulation training is not different from proctored approach. The effect of virtual reality simulators training on acquisition of basic surgical skills does not seem to be different from the effect the physical simulators. Limited data exist on the effect of virtual reality simulation training on the acquisition of visual spatial perception and stress coping skills. Undoubtedly, virtual reality simulation training provides an alternative means of improving performance in laparoscopic surgery. However, future research efforts should focus on the effect of virtual reality simulation on performance in the context of advanced surgical procedure, on standardization of training, on the possibility of synergistic effect of virtual reality simulation training combined with mental training, on personalized training. Copyright © 2014 Surgical Associates Ltd. Published by Elsevier Ltd. All rights reserved.

  12. Computer simulation of thermal plant operations

    CERN Document Server

    O'Kelly, Peter

    2012-01-01

    This book describes thermal plant simulation, that is, dynamic simulation of plants which produce, exchange and otherwise utilize heat as their working medium. Directed at chemical, mechanical and control engineers involved with operations, control and optimization and operator training, the book gives the mathematical formulation and use of simulation models of the equipment and systems typically found in these industries. The author has adopted a fundamental approach to the subject. The initial chapters provide an overview of simulation concepts and describe a suitable computer environment.

  13. Computational aspects in high intensity ultrasonic surgery planning.

    Science.gov (United States)

    Pulkkinen, A; Hynynen, K

    2010-01-01

    Therapeutic ultrasound treatment planning is discussed and computational aspects regarding it are reviewed. Nonlinear ultrasound simulations were solved with a combined frequency domain Rayleigh and KZK model. Ultrasonic simulations were combined with thermal simulations and were used to compute heating of muscle tissue in vivo for four different focused ultrasound transducers. The simulations were compared with measurements and good agreement was found for large F-number transducers. However, at F# 1.9 the simulated rate of temperature rise was approximately a factor of 2 higher than the measured ones. The power levels used with the F# 1 transducer were too low to show any nonlinearity. The simulations were used to investigate the importance of nonlinarities generated in the coupling water, and also the importance of including skin in the simulations. Ignoring either of these in the model would lead to larger errors. Most notably, the nonlinearities generated in the water can enhance the focal temperature by more than 100%. The simulations also demonstrated that pulsed high power sonications may provide an opportunity to significantly (up to a factor of 3) reduce the treatment time. In conclusion, nonlinear propagation can play an important role in shaping the energy distribution during a focused ultrasound treatment and it should not be ignored in planning. However, the current simulation methods are accurate only with relatively large F-numbers and better models need to be developed for sharply focused transducers. Copyright 2009 Elsevier Ltd. All rights reserved.

  14. Numerical characteristics of quantum computer simulation

    Science.gov (United States)

    Chernyavskiy, A.; Khamitov, K.; Teplov, A.; Voevodin, V.; Voevodin, Vl.

    2016-12-01

    The simulation of quantum circuits is significantly important for the implementation of quantum information technologies. The main difficulty of such modeling is the exponential growth of dimensionality, thus the usage of modern high-performance parallel computations is relevant. As it is well known, arbitrary quantum computation in circuit model can be done by only single- and two-qubit gates, and we analyze the computational structure and properties of the simulation of such gates. We investigate the fact that the unique properties of quantum nature lead to the computational properties of the considered algorithms: the quantum parallelism make the simulation of quantum gates highly parallel, and on the other hand, quantum entanglement leads to the problem of computational locality during simulation. We use the methodology of the AlgoWiki project (algowiki-project.org) to analyze the algorithm. This methodology consists of theoretical (sequential and parallel complexity, macro structure, and visual informational graph) and experimental (locality and memory access, scalability and more specific dynamic characteristics) parts. Experimental part was made by using the petascale Lomonosov supercomputer (Moscow State University, Russia). We show that the simulation of quantum gates is a good base for the research and testing of the development methods for data intense parallel software, and considered methodology of the analysis can be successfully used for the improvement of the algorithms in quantum information science.

  15. Computer Simulations of Lipid Nanoparticles

    Directory of Open Access Journals (Sweden)

    Xavier F. Fernandez-Luengo

    2017-12-01

    Full Text Available Lipid nanoparticles (LNP are promising soft matter nanomaterials for drug delivery applications. In spite of their interest, little is known about the supramolecular organization of the components of these self-assembled nanoparticles. Here, we present a molecular dynamics simulation study, employing the Martini coarse-grain forcefield, of self-assembled LNPs made by tripalmitin lipid in water. We also study the adsorption of Tween 20 surfactant as a protective layer on top of the LNP. We show that, at 310 K (the temperature of interest in biological applications, the structure of the lipid nanoparticles is similar to that of a liquid droplet, in which the lipids show no nanostructuration and have high mobility. We show that, for large enough nanoparticles, the hydrophilic headgroups develop an interior surface in the NP core that stores liquid water. The surfactant is shown to organize in an inhomogeneous way at the LNP surface, with patches with high surfactant concentrations and surface patches not covered by surfactant.

  16. Computer aided surgery. Current status and future directions

    International Nuclear Information System (INIS)

    Sato, Yoshinobu

    2006-01-01

    This review describes topics in the title in the order of 3D model reconstruction and therapeutic planning based on images before surgery; registration of the actual images in virtual physical space of the patient who is under surgical operation, to the preoperative ones with use of 3D-position sensor, ultrasonics, endoscopy and X-diaphanoscopy; and their accuracy analysis. Images before surgery usually obtained with CT and MR are reconstructed in 3D for the purpose of therapeutic planning by segmentation of the target organ/site, surrounding organs, bones and blood vessels. Navigation system at the surgery functions to make the images obtained before and during operation to be integrated for their registration and displaying. Usually, the optical marker and camera both equipped in the endoscope, and position sensor (tracker) are used for integration in the operation coordinate system. For this, the actual pictures at liver operation are given. For accuracy analysis there is a theory of target registration error, which has been established on FDA demands. In future, development of technology concerned in this field like that of robot, bio-dynamics, biomaterials, sensor and high performance computing together with 4D document of surgery for feed-back to technology are desirable for the systematic growing of this surgical technology. (T.I.)

  17. An integrated computational tool for precipitation simulation

    Science.gov (United States)

    Cao, W.; Zhang, F.; Chen, S.-L.; Zhang, C.; Chang, Y. A.

    2011-07-01

    Computer aided materials design is of increasing interest because the conventional approach solely relying on experimentation is no longer viable within the constraint of available resources. Modeling of microstructure and mechanical properties during precipitation plays a critical role in understanding the behavior of materials and thus accelerating the development of materials. Nevertheless, an integrated computational tool coupling reliable thermodynamic calculation, kinetic simulation, and property prediction of multi-component systems for industrial applications is rarely available. In this regard, we are developing a software package, PanPrecipitation, under the framework of integrated computational materials engineering to simulate precipitation kinetics. It is seamlessly integrated with the thermodynamic calculation engine, PanEngine, to obtain accurate thermodynamic properties and atomic mobility data necessary for precipitation simulation.

  18. Automatic temperature computation for realistic IR simulation

    Science.gov (United States)

    Le Goff, Alain; Kersaudy, Philippe; Latger, Jean; Cathala, Thierry; Stolte, Nilo; Barillot, Philippe

    2000-07-01

    Polygon temperature computation in 3D virtual scenes is fundamental for IR image simulation. This article describes in detail the temperature calculation software and its current extensions, briefly presented in [1]. This software, called MURET, is used by the simulation workshop CHORALE of the French DGA. MURET is a one-dimensional thermal software, which accurately takes into account the material thermal attributes of three-dimensional scene and the variation of the environment characteristics (atmosphere) as a function of the time. Concerning the environment, absorbed incident fluxes are computed wavelength by wavelength, for each half an hour, druing 24 hours before the time of the simulation. For each polygon, incident fluxes are compsed of: direct solar fluxes, sky illumination (including diffuse solar fluxes). Concerning the materials, classical thermal attributes are associated to several layers, such as conductivity, absorption, spectral emissivity, density, specific heat, thickness and convection coefficients are taken into account. In the future, MURET will be able to simulate permeable natural materials (water influence) and vegetation natural materials (woods). This model of thermal attributes induces a very accurate polygon temperature computation for the complex 3D databases often found in CHORALE simulations. The kernel of MUET consists of an efficient ray tracer allowing to compute the history (over 24 hours) of the shadowed parts of the 3D scene and a library, responsible for the thermal computations. The great originality concerns the way the heating fluxes are computed. Using ray tracing, the flux received in each 3D point of the scene accurately takes into account the masking (hidden surfaces) between objects. By the way, this library supplies other thermal modules such as a thermal shows computation tool.

  19. Software Engineering for Scientific Computer Simulations

    Science.gov (United States)

    Post, Douglass E.; Henderson, Dale B.; Kendall, Richard P.; Whitney, Earl M.

    2004-11-01

    Computer simulation is becoming a very powerful tool for analyzing and predicting the performance of fusion experiments. Simulation efforts are evolving from including only a few effects to many effects, from small teams with a few people to large teams, and from workstations and small processor count parallel computers to massively parallel platforms. Successfully making this transition requires attention to software engineering issues. We report on the conclusions drawn from a number of case studies of large scale scientific computing projects within DOE, academia and the DoD. The major lessons learned include attention to sound project management including setting reasonable and achievable requirements, building a good code team, enforcing customer focus, carrying out verification and validation and selecting the optimum computational mathematics approaches.

  20. Computer simulation of fatigue under diametrical compression

    OpenAIRE

    Carmona, H. A.; Kun, F.; Andrade Jr., J. S.; Herrmann, H. J.

    2006-01-01

    We study the fatigue fracture of disordered materials by means of computer simulations of a discrete element model. We extend a two-dimensional fracture model to capture the microscopic mechanisms relevant for fatigue, and we simulate the diametric compression of a disc shape specimen under a constant external force. The model allows to follow the development of the fracture process on the macro- and micro-level varying the relative influence of the mechanisms of damage accumulation over the ...

  1. Realistic soft tissue deformation strategies for real time surgery simulation.

    Science.gov (United States)

    Shen, Yunhe; Zhou, Xiangmin; Zhang, Nan; Tamma, Kumar; Sweet, Robert

    2008-01-01

    A volume-preserving deformation method (VPDM) is developed in complement with the mass-spring method (MSM) to improve the deformation quality of the MSM to model soft tissue in surgical simulation. This method can also be implemented as a stand-alone model. The proposed VPDM satisfies the Newton's laws of motion by obtaining the resultant vectors form an equilibrium condition. The proposed method has been tested in virtual surgery systems with haptic rendering demands.

  2. Computer-assisted navigational surgery enhances safety in dental implantology.

    Science.gov (United States)

    Ng, F C; Ho, K H; Wexler, A

    2005-06-01

    Dental implants are increasingly used to restore missing dentition. These titanium implants are surgically installed in the edentulous alveolar ridge and allowed to osteointegrate with the bone during the healing phase. After osseo-integration, the implant is loaded with a prosthesis to replace the missing tooth. Conventional implant treatment planning uses study models, wax-ups and panoramic x-rays to prefabricate surgical stent to guide the preparation of the implant site. The drilling into the alveolar ridge is invariably a "blind" procedure as the part of the drill in bone is not visible. Stereotactic systems were first introduced into neurosurgery in 1986. Since then, computer-assisted navigational technology has brought major advances to neuro-, midface and orthopaedic surgeries, and more recently, to implant placement. This paper illustrates the use of real-time computer-guided navigational technology in enhancing safety in implant surgical procedures. Real-time computer-guided navigational technology enhances accuracy and precision of the surgical procedure, minimises complications and facilitates surgery in challenging anatomical locations.

  3. Developing effective automated feedback in temporal bone surgery simulation.

    Science.gov (United States)

    Wijewickrema, Sudanthi; Piromchai, Patorn; Zhou, Yun; Ioannou, Ioanna; Bailey, James; Kennedy, Gregor; O'Leary, Stephen

    2015-06-01

    We aim to test the effectiveness, accuracy, and usefulness of an automated feedback system in facilitating skill acquisition in virtual reality surgery. We evaluate the performance of the feedback system through a randomized controlled trial of 24 students allocated to feedback and nonfeedback groups. The feedback system was based on the Melbourne University temporal bone surgery simulator. The study was conducted at the simulation laboratory of the Royal Victorian Eye and Ear Hospital, Melbourne. The study participants were medical students from the University of Melbourne, who were asked to perform virtual cortical mastoidectomy on the simulator. The extent to which the drilling behavior of the feedback and nonfeedback groups differed was used to evaluate the effectiveness of the system. Its accuracy was determined through a postexperiment observational assessment of recordings made during the experiment by an expert surgeon. Its usability was evaluated using students' self-reports of their impressions of the system. A Friedman's test showed that there was a significant improvement in the drilling performance of the feedback group, χ(2)(1) = 14.450, P feedback (when trainee behavior was detected) 88.6% of the time and appropriate feedback (accurate advice) 84.2% of the time. Participants' opinions about the usefulness of the system were highly positive. The automated feedback system was observed to be effective in improving surgical technique, and the provided feedback was found to be accurate and useful. © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2015.

  4. Normal postperative computed tomography findings after avariety of pancreatic surgeries

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Ji Won; Hwang, Ho Kyoung; Lee, Min Wook; Kim, Ki Whang; Kang, Chang Moo; Kim, Myeong Jin; Chung, Yong Eun [Yonsei University College of Medicine, Seoul (Korea, Republic of)

    2017-04-15

    Pancreatic surgery remains the only curative treatment for pancreatic neoplasms, and plays an important role in the management of medically intractable diseases. Since the original Whipple operation in the 20th century, surgical techniques have advanced, resulting in decreased postoperative complications and better clinical outcomes. Normal postoperative imaging findings vary greatly depending on the surgical technique used. Radiologists are required to be familiar with the normal postoperative imaging findings, in order to distinguish from postoperative complications or tumor recurrence. In this study, we briefly review a variety of surgical techniques for the pancreas, and present the normal postoperative computed tomography findings.

  5. Computer simulation of ultrasonic waves in solids

    International Nuclear Information System (INIS)

    Thibault, G.A.; Chaplin, K.

    1992-01-01

    A computer model that simulates the propagation of ultrasonic waves has been developed at AECL Research, Chalk River Laboratories. This program is called EWE, short for Elastic Wave Equations, the mathematics governing the propagation of ultrasonic waves. This report contains a brief summary of the use of ultrasonic waves in non-destructive testing techniques, a discussion of the EWE simulation code explaining the implementation of the equations and the types of output received from the model, and an example simulation showing the abilities of the model. (author). 2 refs., 2 figs

  6. The use of simulators in the learning for otologic surgery

    Directory of Open Access Journals (Sweden)

    Sousa, Ana Maria Almeida de

    2011-10-01

    Full Text Available Introduction: The teaching method of "learn by doing it'' was created by Halsted e col. In the beginning of 20th century creating the first model of medical residence in the world. This learning develops in three phases: cognitive, associative and autonomous, through an ascending curve. The simulators appeared in the last years as a complement to the cognitive phase, adding efforts to the training, performed before only in animals and cadavers, ever more hampered by medical and legal dilemmas. Objective: Describe and compare the various types of simulators available for the learning of otological surgery. Data synthesis: The model of simulators are divided mainly in real and virtual models, each having its peculiarities with positive and negative points. The main point of each one of them is the sensory feedback granted by each one of them, what we call it haptic reality: coloring of the structure dissected; listening to the corresponding sounds; as the drill or vacuum; presence of a joystick that simulates the pen motor; use of glasses or even a microscope for three dimensional view; use of a real otologic surgical instrument. The cost of the differents types of simulators is also a key point for the implementation of them in the daily reality of the training centers. Is important to mention that some of these simulators allow the training students and can be objectively evaluated by the simulator itself. Conclusion: Simulators are seen as a complementary tool for training and improvement of the otological surgeons.

  7. Acute mediastinitis: multidetector computed tomography findings following cardiac surgery

    International Nuclear Information System (INIS)

    Macedo, Clarissa Aguiar de; Baena, Marcos Eduardo da Silva; Uezumi, Kiyomi Kato; Castro, Claudio Campi de; Lucarelli, Claudio Luiz; Cerri, Giovanni Guido

    2008-01-01

    Postoperative mediastinitis is defined as an infection of the organs and tissues in the mediastinal space, with an incidence ranging between 0.4% and 5% of cases. This disease severity varies from infection of superficial tissues in the chest wall to fulminant mediastinitis with sternal involvement. Diagnostic criterion for postoperative detection of acute mediastinitis at computed tomography is the presence of fluid collections and gas in the mediastinal space, which might or might not be associated with peristernal abnormalities such as edema of soft tissues, separation of sternal segments with marginal bone resorption, sclerosis and osteomyelitis. Other associated findings include lymphadenomegaly, pulmonary consolidation and pleural/ pericardial effusion. Some of these findings, such as mediastinal gas and small fluid collections can be typically found in the absence of infection, early in the period following thoracic surgery where the effectiveness of computed tomography is limited. After approximately two weeks, computed tomography achieves almost 100% sensitivity and specificity. Patients with clinical suspicion of mediastinitis should be submitted to computed tomography for investigating the presence of fluid collections to identify the extent and nature of the disease. Multidetector computed tomography allows 3D images reconstruction, contributing particularly to the evaluation of the sternum. (author)

  8. Acute mediastinitis: multidetector computed tomography findings following cardiac surgery

    Energy Technology Data Exchange (ETDEWEB)

    Macedo, Clarissa Aguiar de [Universidade de Sao Paulo (USP), SP (Brazil). Faculdade de Medicina. Instituto do Coracao (InCor)]. E-mail: clarissaaguiarm@yahoo.com.br; Baena, Marcos Eduardo da Silva [Instituto do Coracao (InCor), Sao Paulo, SP (Brazil). Unit of Ultrasonography; Uezumi, Kiyomi Kato [Instituto do Coracao (InCor), Sao Paulo, SP (Brazil). Unit of Computed Tomography; Castro, Claudio Campi de [Instituto do Coracao (InCor), Sao Paulo, SP (Brazil). Unit of Magnetic Resonance Imaging; Lucarelli, Claudio Luiz [Instituto do Coracao (InCor), Sao Paulo, SP (Brazil). Center of Diagnosis; Cerri, Giovanni Guido [Universidade de Sao Paulo (USP), SP (Brazil). School of Medicine. Dept. of Radiology

    2008-07-15

    Postoperative mediastinitis is defined as an infection of the organs and tissues in the mediastinal space, with an incidence ranging between 0.4% and 5% of cases. This disease severity varies from infection of superficial tissues in the chest wall to fulminant mediastinitis with sternal involvement. Diagnostic criterion for postoperative detection of acute mediastinitis at computed tomography is the presence of fluid collections and gas in the mediastinal space, which might or might not be associated with peristernal abnormalities such as edema of soft tissues, separation of sternal segments with marginal bone resorption, sclerosis and osteomyelitis. Other associated findings include lymphadenomegaly, pulmonary consolidation and pleural/ pericardial effusion. Some of these findings, such as mediastinal gas and small fluid collections can be typically found in the absence of infection, early in the period following thoracic surgery where the effectiveness of computed tomography is limited. After approximately two weeks, computed tomography achieves almost 100% sensitivity and specificity. Patients with clinical suspicion of mediastinitis should be submitted to computed tomography for investigating the presence of fluid collections to identify the extent and nature of the disease. Multidetector computed tomography allows 3D images reconstruction, contributing particularly to the evaluation of the sternum. (author)

  9. Computer simulation of multiple dynamic photorefractive gratings

    DEFF Research Database (Denmark)

    Buchhave, Preben

    1998-01-01

    The benefits of a direct visualization of space-charge grating buildup are described. The visualization is carried out by a simple repetitive computer program, which simulates the basic processes in the band-transport model and displays the result graphically or in the form of numerical data. The...

  10. Using Computer Simulations in Chemistry Problem Solving

    Science.gov (United States)

    Avramiotis, Spyridon; Tsaparlis, Georgios

    2013-01-01

    This study is concerned with the effects of computer simulations of two novel chemistry problems on the problem solving ability of students. A control-experimental group, equalized by pair groups (n[subscript Exp] = n[subscript Ctrl] = 78), research design was used. The students had no previous experience of chemical practical work. Student…

  11. Computer simulations of the random barrier model

    DEFF Research Database (Denmark)

    Schrøder, Thomas; Dyre, Jeppe

    2002-01-01

    A brief review of experimental facts regarding ac electronic and ionic conduction in disordered solids is given followed by a discussion of what is perhaps the simplest realistic model, the random barrier model (symmetric hopping model). Results from large scale computer simulations are presented...

  12. Macromod: Computer Simulation For Introductory Economics

    Science.gov (United States)

    Ross, Thomas

    1977-01-01

    The Macroeconomic model (Macromod) is a computer assisted instruction simulation model designed for introductory economics courses. An evaluation of its utilization at a community college indicates that it yielded a 10 percent to 13 percent greater economic comprehension than lecture classes and that it met with high student approval. (DC)

  13. Computer Graphics Simulations of Sampling Distributions.

    Science.gov (United States)

    Gordon, Florence S.; Gordon, Sheldon P.

    1989-01-01

    Describes the use of computer graphics simulations to enhance student understanding of sampling distributions that arise in introductory statistics. Highlights include the distribution of sample proportions, the distribution of the difference of sample means, the distribution of the difference of sample proportions, and the distribution of sample…

  14. The Australian Computational Earth Systems Simulator

    Science.gov (United States)

    Mora, P.; Muhlhaus, H.; Lister, G.; Dyskin, A.; Place, D.; Appelbe, B.; Nimmervoll, N.; Abramson, D.

    2001-12-01

    Numerical simulation of the physics and dynamics of the entire earth system offers an outstanding opportunity for advancing earth system science and technology but represents a major challenge due to the range of scales and physical processes involved, as well as the magnitude of the software engineering effort required. However, new simulation and computer technologies are bringing this objective within reach. Under a special competitive national funding scheme to establish new Major National Research Facilities (MNRF), the Australian government together with a consortium of Universities and research institutions have funded construction of the Australian Computational Earth Systems Simulator (ACcESS). The Simulator or computational virtual earth will provide the research infrastructure to the Australian earth systems science community required for simulations of dynamical earth processes at scales ranging from microscopic to global. It will consist of thematic supercomputer infrastructure and an earth systems simulation software system. The Simulator models and software will be constructed over a five year period by a multi-disciplinary team of computational scientists, mathematicians, earth scientists, civil engineers and software engineers. The construction team will integrate numerical simulation models (3D discrete elements/lattice solid model, particle-in-cell large deformation finite-element method, stress reconstruction models, multi-scale continuum models etc) with geophysical, geological and tectonic models, through advanced software engineering and visualization technologies. When fully constructed, the Simulator aims to provide the software and hardware infrastructure needed to model solid earth phenomena including global scale dynamics and mineralisation processes, crustal scale processes including plate tectonics, mountain building, interacting fault system dynamics, and micro-scale processes that control the geological, physical and dynamic

  15. Computational algorithms for simulations in atmospheric optics.

    Science.gov (United States)

    Konyaev, P A; Lukin, V P

    2016-04-20

    A computer simulation technique for atmospheric and adaptive optics based on parallel programing is discussed. A parallel propagation algorithm is designed and a modified spectral-phase method for computer generation of 2D time-variant random fields is developed. Temporal power spectra of Laguerre-Gaussian beam fluctuations are considered as an example to illustrate the applications discussed. Implementation of the proposed algorithms using Intel MKL and IPP libraries and NVIDIA CUDA technology is shown to be very fast and accurate. The hardware system for the computer simulation is an off-the-shelf desktop with an Intel Core i7-4790K CPU operating at a turbo-speed frequency up to 5 GHz and an NVIDIA GeForce GTX-960 graphics accelerator with 1024 1.5 GHz processors.

  16. Procedural virtual reality simulation in minimally invasive surgery.

    Science.gov (United States)

    Våpenstad, Cecilie; Buzink, Sonja N

    2013-02-01

    Simulation of procedural tasks has the potential to bridge the gap between basic skills training outside the operating room (OR) and performance of complex surgical tasks in the OR. This paper provides an overview of procedural virtual reality (VR) simulation currently available on the market and presented in scientific literature for laparoscopy (LS), flexible gastrointestinal endoscopy (FGE), and endovascular surgery (EVS). An online survey was sent to companies and research groups selling or developing procedural VR simulators, and a systematic search was done for scientific publications presenting or applying VR simulators to train or assess procedural skills in the PUBMED and SCOPUS databases. The results of five simulator companies were included in the survey. In the literature review, 116 articles were analyzed (45 on LS, 43 on FGE, 28 on EVS), presenting a total of 23 simulator systems. The companies stated to altogether offer 78 procedural tasks (33 for LS, 12 for FGE, 33 for EVS), of which 17 also were found in the literature review. Although study type and used outcomes vary between the three different fields, approximately 90 % of the studies presented in the retrieved publications for LS found convincing evidence to confirm the validity or added value of procedural VR simulation. This was the case in approximately 75 % for FGE and EVS. Procedural training using VR simulators has been found to improve clinical performance. There is nevertheless a large amount of simulated procedural tasks that have not been validated. Future research should focus on the optimal use of procedural simulators in the most effective training setups and further investigate the benefits of procedural VR simulation to improve clinical outcome.

  17. Interoceanic canal excavation scheduling via computer simulation

    Energy Technology Data Exchange (ETDEWEB)

    Baldonado, Orlino C [Holmes and Narver, Inc., Los Angeles, CA (United States)

    1970-05-15

    The computer simulation language GPSS/360 was used to simulate the schedule of several nuclear detonation programs for the interoceanic canal project. The effects of using different weather restriction categories due to air blast and fallout were investigated. The effect of increasing the number of emplacement and stemming crews and the effect of varying the reentry period after detonating a row charge or salvo were also studied. Detonation programs were simulated for the proposed Routes 17A and 25E. The study demonstrates the method of using computer simulation so that a schedule and its associated constraints can be assessed for feasibility. Since many simulation runs can be made for a given set of detonation program constraints, one readily obtains an average schedule for a range of conditions. This provides a method for analyzing time-sensitive operations so that time and cost-effective operational schedules can be established. A comparison of the simulated schedules with those that were published shows them to be similar. (author)

  18. Interoceanic canal excavation scheduling via computer simulation

    International Nuclear Information System (INIS)

    Baldonado, Orlino C.

    1970-01-01

    The computer simulation language GPSS/360 was used to simulate the schedule of several nuclear detonation programs for the interoceanic canal project. The effects of using different weather restriction categories due to air blast and fallout were investigated. The effect of increasing the number of emplacement and stemming crews and the effect of varying the reentry period after detonating a row charge or salvo were also studied. Detonation programs were simulated for the proposed Routes 17A and 25E. The study demonstrates the method of using computer simulation so that a schedule and its associated constraints can be assessed for feasibility. Since many simulation runs can be made for a given set of detonation program constraints, one readily obtains an average schedule for a range of conditions. This provides a method for analyzing time-sensitive operations so that time and cost-effective operational schedules can be established. A comparison of the simulated schedules with those that were published shows them to be similar. (author)

  19. Computer simulation on molten ionic salts

    International Nuclear Information System (INIS)

    Kawamura, K.; Okada, I.

    1978-01-01

    The extensive advances in computer technology have since made it possible to apply computer simulation to the evaluation of the macroscopic and microscopic properties of molten salts. The evaluation of the potential energy in molten salts systems is complicated by the presence of long-range energy, i.e. Coulomb energy, in contrast to simple liquids where the potential energy is easily evaluated. It has been shown, however, that no difficulties are encountered when the Ewald method is applied to the evaluation of Coulomb energy. After a number of attempts had been made to approximate the pair potential, the Huggins-Mayer potential based on ionic crystals became the most often employed. Since it is thought that the only appreciable contribution to many-body potential, not included in Huggins-Mayer potential, arises from the internal electrostatic polarization of ions in molten ionic salts, computer simulation with a provision for ion polarization has been tried recently. The computations, which are employed mainly for molten alkali halides, can provide: (1) thermodynamic data such as internal energy, internal pressure and isothermal compressibility; (2) microscopic configurational data such as radial distribution functions; (3) transport data such as the diffusion coefficient and electrical conductivity; and (4) spectroscopic data such as the intensity of inelastic scattering and the stretching frequency of simple molecules. The computed results seem to agree well with the measured results. Computer simulation can also be used to test the effectiveness of a proposed pair potential and the adequacy of postulated models of molten salts, and to obtain experimentally inaccessible data. A further application of MD computation employing the pair potential based on an ionic model to BeF 2 , ZnCl 2 and SiO 2 shows the possibility of quantitative interpretation of structures and glass transformation phenomena

  20. Validation of Robotic Surgery Simulator (RoSS).

    Science.gov (United States)

    Kesavadas, Thenkurussi; Stegemann, Andrew; Sathyaseelan, Gughan; Chowriappa, Ashirwad; Srimathveeravalli, Govindarajan; Seixas-Mikelus, Stéfanie; Chandrasekhar, Rameella; Wilding, Gregory; Guru, Khurshid

    2011-01-01

    Recent growth of daVinci Robotic Surgical System as a minimally invasive surgery tool has led to a call for better training of future surgeons. In this paper, a new virtual reality simulator, called RoSS is presented. Initial results from two studies - face and content validity, are very encouraging. 90% of the cohort of expert robotic surgeons felt that the simulator was excellent or somewhat close to the touch and feel of the daVinci console. Content validity of the simulator received 90% approval in some cases. These studies demonstrate that RoSS has the potential of becoming an important training tool for the daVinci surgical robot.

  1. Virtual reality based surgery simulation for endoscopic gynaecology.

    Science.gov (United States)

    Székely, G; Bajka, M; Brechbühler, C; Dual, J; Enzler, R; Haller, U; Hug, J; Hutter, R; Ironmonger, N; Kauer, M; Meier, V; Niederer, P; Rhomberg, A; Schmid, P; Schweitzer, G; Thaler, M; Vuskovic, V; Tröster, G

    1999-01-01

    Virtual reality (VR) based surgical simulator systems offer very elegant possibilities to both enrich and enhance traditional education in endoscopic surgery. However, while a wide range of VR simulator systems have been proposed and realized in the past few years, most of these systems are far from able to provide a reasonably realistic surgical environment. We explore the basic approaches to the current limits of realism and ultimately seek to extend these based on our description and analysis of the most important components of a VR-based endoscopic simulator. The feasibility of the proposed techniques is demonstrated on a first modular prototype system implementing the basic algorithms for VR-training in gynaecologic laparoscopy.

  2. Computed tomography evaluation of autogenous graft in sinus lift surgery

    International Nuclear Information System (INIS)

    Ajzen, Sergio Aron; Moscatiello, Rafael Andrade; Lima, Aida Maria Custodio de; Moscatiello, Vitoria Aparecida Muglia; Helio Kiitiro Yamashita; Mosacatiello, Rafael Muglia; Nishiguchi, Celso Itiro; Alves, Maria Teresa de Seixas

    2001-01-01

    The objective was to quantify bone formation within autogenous bone grafts and autogenous bone grafts in combination with platelet-rich plasma obtained either from apheresis or centrifugation using computed tomography. This prospective, double-blind study was conducted in 34 male and female adult patients (mean age of 28 years and 8 months), with either unilateral or bilateral pneumatization of the maxillary sinuses, requiring bone graft for dental implant. All patients were submitted to computed tomography examinations prior and six months after sinus lift surgery. Fifty-three maxillary sinuses were operated and divided into three distinct groups: autogenous bone graft, autogenous bone graft in combination with platelet-rich plasma obtained by centrifugation, and autogenous bone graft in combination with platelet-rich plasma obtained by apheresis. The results showed that computed tomography demonstrated bone growth in height and width between the initial and the follow-up computed tomography scans in all three groups. However, no statistical difference was found either for bone height or width. It was concluded that clinical evidence demonstrates the effectiveness of autogenous bone grafts, particularly when used in combination with bone growth factors such as platelet-rich plasma, which allow prosthetic and functional restoration of maxillofacial structures through fixation of dental implants. (author)

  3. Fluid dynamics theory, computation, and numerical simulation

    CERN Document Server

    Pozrikidis, C

    2001-01-01

    Fluid Dynamics Theory, Computation, and Numerical Simulation is the only available book that extends the classical field of fluid dynamics into the realm of scientific computing in a way that is both comprehensive and accessible to the beginner The theory of fluid dynamics, and the implementation of solution procedures into numerical algorithms, are discussed hand-in-hand and with reference to computer programming This book is an accessible introduction to theoretical and computational fluid dynamics (CFD), written from a modern perspective that unifies theory and numerical practice There are several additions and subject expansions in the Second Edition of Fluid Dynamics, including new Matlab and FORTRAN codes Two distinguishing features of the discourse are solution procedures and algorithms are developed immediately after problem formulations are presented, and numerical methods are introduced on a need-to-know basis and in increasing order of difficulty Matlab codes are presented and discussed for a broad...

  4. Fluid Dynamics Theory, Computation, and Numerical Simulation

    CERN Document Server

    Pozrikidis, Constantine

    2009-01-01

    Fluid Dynamics: Theory, Computation, and Numerical Simulation is the only available book that extends the classical field of fluid dynamics into the realm of scientific computing in a way that is both comprehensive and accessible to the beginner. The theory of fluid dynamics, and the implementation of solution procedures into numerical algorithms, are discussed hand-in-hand and with reference to computer programming. This book is an accessible introduction to theoretical and computational fluid dynamics (CFD), written from a modern perspective that unifies theory and numerical practice. There are several additions and subject expansions in the Second Edition of Fluid Dynamics, including new Matlab and FORTRAN codes. Two distinguishing features of the discourse are: solution procedures and algorithms are developed immediately after problem formulations are presented, and numerical methods are introduced on a need-to-know basis and in increasing order of difficulty. Matlab codes are presented and discussed for ...

  5. Computer simulation of driven Alfven waves

    International Nuclear Information System (INIS)

    Geary, J.L. Jr.

    1986-01-01

    The first particle simulation study of shear Alfven wave resonance heating is presented. Particle simulation codes self-consistently follow the time evolution of the individual and collective aspects of particle dynamics as well as wave dynamics in a fully nonlinear fashion. Alfven wave heating is a possible means of increasing the temperature of magnetized plasmas. A new particle simulation model was developed for this application that incorporates Darwin's formulation of the electromagnetic fields with a guiding center approximation for electron motion perpendicular to the ambient magnetic field. The implementation of this model and the examination of its theoretical and computational properties are presented. With this model, several cases of Alfven wave heating is examined in both uniform and nonuniform simulation systems in a two dimensional slab. For the inhomogeneous case studies, the kinetic Alfven wave develops in the vicinity of the shear Alfven resonance region

  6. Topics in computer simulations of statistical systems

    International Nuclear Information System (INIS)

    Salvador, R.S.

    1987-01-01

    Several computer simulations studying a variety of topics in statistical mechanics and lattice gauge theories are performed. The first study describes a Monte Carlo simulation performed on Ising systems defined on Sierpinsky carpets of dimensions between one and four. The critical coupling and the exponent γ are measured as a function of dimension. The Ising gauge theory in d = 4 - epsilon, for epsilon → 0 + , is then studied by performing a Monte Carlo simulation for the theory defined on fractals. A high statistics Monte Carlo simulation for the three-dimensional Ising model is presented for lattices of sizes 8 3 to 44 3 . All the data obtained agrees completely, within statistical errors, with the forms predicted by finite-sizing scaling. Finally, a method to estimate numerically the partition function of statistical systems is developed

  7. A 3D virtual reality simulator for training of minimally invasive surgery.

    Science.gov (United States)

    Mi, Shao-Hua; Hou, Zeng-Gunag; Yang, Fan; Xie, Xiao-Liang; Bian, Gui-Bin

    2014-01-01

    For the last decade, remarkable progress has been made in the field of cardiovascular disease treatment. However, these complex medical procedures require a combination of rich experience and technical skills. In this paper, a 3D virtual reality simulator for core skills training in minimally invasive surgery is presented. The system can generate realistic 3D vascular models segmented from patient datasets, including a beating heart, and provide a real-time computation of force and force feedback module for surgical simulation. Instruments, such as a catheter or guide wire, are represented by a multi-body mass-spring model. In addition, a realistic user interface with multiple windows and real-time 3D views are developed. Moreover, the simulator is also provided with a human-machine interaction module that gives doctors the sense of touch during the surgery training, enables them to control the motion of a virtual catheter/guide wire inside a complex vascular model. Experimental results show that the simulator is suitable for minimally invasive surgery training.

  8. Blended learning in surgery using the Inmedea Simulator.

    Science.gov (United States)

    Funke, Katrin; Bonrath, Esther; Mardin, Wolf Arif; Becker, Jan Carl; Haier, Joerg; Senninger, Norbert; Vowinkel, Thorsten; Hoelzen, Jens Peter; Mees, Soeren Torge

    2013-02-01

    Recently, medical education in surgery has experienced several modifications. We have implemented a blended learning module in our teaching curriculum to evaluate its effectiveness, applicability, and acceptance in surgical education. In this prospective study, the traditional face-to-face learning of our teaching curriculum for fourth-year medical students (n = 116) was augmented by the Inmedea Simulator, a web-based E-learning system, with six virtual patient cases. Student results were documented by the system and learning success was determined by comparing patient cases with comparable diseases (second and sixth case). The acceptance among the students was evaluated with a questionnaire. After using the Inmedea Simulator, correct diagnoses were found significantly (P blended learning (score 2.5 ± 1.2) to conventional teaching. The blended learning approach using the Inmedea Simulator was highly appreciated by our medical students and resulted in a significant learning success. Blended learning appears to be a suitable tool to complement traditional teaching in surgery.

  9. Residents' response to bleeding during a simulated robotic surgery task.

    Science.gov (United States)

    Walker, Jessica L; Nathwani, Jay N; Mohamadipanah, Hossein; Laufer, Shlomi; Jocewicz, Frank F; Gwillim, Eran; Pugh, Carla M

    2017-12-01

    The aim of this study was to assess performance measurement validity of our newly developed robotic surgery task trainer. We hypothesized that residents would exhibit wide variations in their intercohort performance as well as a measurable difference compared to surgeons in fellowship training. Our laboratory synthesized a model of a pelvic tumor that simulates unexpected bleeding. Surgical residents and fellows of varying specialties completed a demographic survey and were allowed 20 minutes to resect the tumor using the da Vinci robot and achieve hemostasis. At a standardized event in the simulation, venous bleeding began, and participants attempted hemostasis using suture ligation. A motion tracking system, using electromagnetic sensors, recorded participants' hand movements. A postparticipation Likert scale survey evaluated participants' assessment of the model's realism and usefulness. Three of the seven residents (postgraduate year 2-5), and the fellow successfully resected the tumor in the allotted time. Residents showed high variability in performance and blood loss (125-700 mL) both within their cohort and compared to the fellow (150 mL blood). All participants rated the model as having high realism and utility for trainees. The results support that our bleeding pelvic tumor simulator has the ability to discriminate resident performance in robotic surgery. The combination of motion, decision-making, and blood loss metrics offers a multilevel performance assessment, analyzing both technical and decision-making abilities. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Computational fluid dynamics for sport simulation

    CERN Document Server

    2009-01-01

    All over the world sport plays a prominent role in society: as a leisure activity for many, as an ingredient of culture, as a business and as a matter of national prestige in such major events as the World Cup in soccer or the Olympic Games. Hence, it is not surprising that science has entered the realm of sports, and, in particular, that computer simulation has become highly relevant in recent years. This is explored in this book by choosing five different sports as examples, demonstrating that computational science and engineering (CSE) can make essential contributions to research on sports topics on both the fundamental level and, eventually, by supporting athletes’ performance.

  11. Computer assisted surgery for malunited fractures in upper limb

    International Nuclear Information System (INIS)

    Yoneda, Masahiro; Kazuki, Kenichi; Uemura, Takuya; Okada, Mitsuhiro; Takaoka, Kunio

    2006-01-01

    Our objective was to evaluate the usefulness of computer-assisted preoperative simulation of malunited fractures in the upper limb. Ten patients with malunited fractures underwent multislice computed tomography of both upper limbs with reconstruction of three-dimensional bone models using three-dimensional (3D) software. Preoperative simulation was comprised of four main procedures: performance of virtual corrective osteotomy, matching of reposition with a mirror-image model of the unaffected side, creating new data for the bone defect, and machining of an hydroxyapatite block as bone graft. In addition, we used full-sized three-dimensional virtual reality modeling with a rapid prototyping molding device, and performed preoperative rehearsals of osteotomies using plaster models. All patients tolerated the surgical procedure well. This technique permits the surgeon to recognize and correct three-dimensional deformities of malunited fracture with both accuracy and precision. (author)

  12. Computational plasticity algorithm for particle dynamics simulations

    Science.gov (United States)

    Krabbenhoft, K.; Lyamin, A. V.; Vignes, C.

    2018-01-01

    The problem of particle dynamics simulation is interpreted in the framework of computational plasticity leading to an algorithm which is mathematically indistinguishable from the common implicit scheme widely used in the finite element analysis of elastoplastic boundary value problems. This algorithm provides somewhat of a unification of two particle methods, the discrete element method and the contact dynamics method, which usually are thought of as being quite disparate. In particular, it is shown that the former appears as the special case where the time stepping is explicit while the use of implicit time stepping leads to the kind of schemes usually labelled contact dynamics methods. The framing of particle dynamics simulation within computational plasticity paves the way for new approaches similar (or identical) to those frequently employed in nonlinear finite element analysis. These include mixed implicit-explicit time stepping, dynamic relaxation and domain decomposition schemes.

  13. Time reversibility, computer simulation, algorithms, chaos

    CERN Document Server

    Hoover, William Graham

    2012-01-01

    A small army of physicists, chemists, mathematicians, and engineers has joined forces to attack a classic problem, the "reversibility paradox", with modern tools. This book describes their work from the perspective of computer simulation, emphasizing the author's approach to the problem of understanding the compatibility, and even inevitability, of the irreversible second law of thermodynamics with an underlying time-reversible mechanics. Computer simulation has made it possible to probe reversibility from a variety of directions and "chaos theory" or "nonlinear dynamics" has supplied a useful vocabulary and a set of concepts, which allow a fuller explanation of irreversibility than that available to Boltzmann or to Green, Kubo and Onsager. Clear illustration of concepts is emphasized throughout, and reinforced with a glossary of technical terms from the specialized fields which have been combined here to focus on a common theme. The book begins with a discussion, contrasting the idealized reversibility of ba...

  14. Computer simulation of displacement cascades in copper

    International Nuclear Information System (INIS)

    Heinisch, H.L.

    1983-06-01

    More than 500 displacement cascades in copper have been generated with the computer simulation code MARLOWE over an energy range pertinent to both fission and fusion neutron spectra. Three-dimensional graphical depictions of selected cascades, as well as quantitative analysis of cascade shapes and sizes and defect densities, illustrate cascade behavior as a function of energy. With increasing energy, the transition from production of single compact damage regions to widely spaced multiple damage regions is clearly demonstrated

  15. Computer Simulation of Multidimensional Archaeological Artefacts

    Directory of Open Access Journals (Sweden)

    Vera Moitinho de Almeida

    2012-11-01

    Our project focuses on the Neolithic lakeside site of La Draga (Banyoles, Catalonia. In this presentation we will begin by providing a clear overview of the major guidelines used to capture and process 3D digital data of several wooden artefacts. Then, we shall present the use of semi-automated relevant feature extractions. Finally, we intend to share preliminary computer simulation issues.

  16. Computer simulation of complexity in plasmas

    International Nuclear Information System (INIS)

    Hayashi, Takaya; Sato, Tetsuya

    1998-01-01

    By making a comprehensive comparative study of many self-organizing phenomena occurring in magnetohydrodynamics and kinetic plasmas, we came up with a hypothetical grand view of self-organization. This assertion is confirmed by a recent computer simulation for a broader science field, specifically, the structure formation of short polymer chains, where the nature of the interaction is completely different from that of plasmas. It is found that the formation of the global orientation order proceeds stepwise. (author)

  17. Computer simulation of molecular sorption in zeolites

    International Nuclear Information System (INIS)

    Calmiano, Mark Daniel

    2001-01-01

    The work presented in this thesis encompasses the computer simulation of molecular sorption. In Chapter 1 we outline the aims and objectives of this work. Chapter 2 follows in which an introduction to sorption in zeolites is presented, with discussion of structure and properties of the main zeolites studied. Chapter 2 concludes with a description of the principles and theories of adsorption. In Chapter 3 we describe the methodology behind the work carried out in this thesis. In Chapter 4 we present our first computational study, that of the sorption of krypton in silicalite. We describe work carried out to investigate low energy sorption sites of krypton in silicalite where we observe krypton to preferentially sorb into straight and sinusoidal channels over channel intersections. We simulate single step type I adsorption isotherms and use molecular dynamics to study the diffusion of krypton and obtain division coefficients and the activation energy. We compare our results to previous experimental and computational studies where we show our work to be in good agreement. In Chapter 5 we present a systematic study of the sorption of oxygen and nitrogen in five lithium substituted zeolites using a transferable interatomic potential that we have developed from ab initio calculations. We show increased loading of nitrogen compared to oxygen in all five zeolites studied as expected and simulate adsorption isotherms, which we compare to experimental and simulated data in the literature. In Chapter 6 we present work on the sorption of ferrocene in the zeolite NaY. We show that a simulated, low energy sorption site for ferrocene is correctly located by comparing to X-ray powder diffraction results for this same system. The thesis concludes with some overall conclusions and discussion of opportunities for future work. (author)

  18. Neurosurgical simulation by interactive computer graphics on iPad.

    Science.gov (United States)

    Maruyama, Keisuke; Kin, Taichi; Saito, Toki; Suematsu, Shinya; Gomyo, Miho; Noguchi, Akio; Nagane, Motoo; Shiokawa, Yoshiaki

    2014-11-01

    Presurgical simulation before complicated neurosurgery is a state-of-the-art technique, and its usefulness has recently become well known. However, simulation requires complex image processing, which hinders its widespread application. We explored handling the results of interactive computer graphics on the iPad tablet, which can easily be controlled anywhere. Data from preneurosurgical simulations from 12 patients (4 men, 8 women) who underwent complex brain surgery were loaded onto an iPad. First, DICOM data were loaded using Amira visualization software to create interactive computer graphics, and ParaView, another free visualization software package, was used to convert the results of the simulation to be loaded using the free iPad software KiwiViewer. The interactive computer graphics created prior to neurosurgery were successfully displayed and smoothly controlled on the iPad in all patients. The number of elements ranged from 3 to 13 (mean 7). The mean original data size was 233 MB, which was reduced to 10.4 MB (4.4% of original size) after image processing by ParaView. This was increased to 46.6 MB (19.9%) after decompression in KiwiViewer. Controlling the magnification, transfer, rotation, and selection of translucence in 10 levels of each element were smoothly and easily performed using one or two fingers. The requisite skill to smoothly control the iPad software was acquired within 1.8 trials on average in 12 medical students and 6 neurosurgical residents. Using an iPad to handle the result of preneurosurgical simulation was extremely useful because it could easily be handled anywhere.

  19. Computer-assisted Orthopaedic Surgery: Current State and Future Perspective

    Directory of Open Access Journals (Sweden)

    Guoyan eZheng

    2015-12-01

    Full Text Available Introduced about two decades ago, computer-assisted orthopaedic surgery (CAOS has emerged as a new and independent area, due to the importance of treatment of musculoskeletal diseases in orthopaedics and traumatology, increasing availability of different imaging modalities, and advances in analytics and navigation tools. The aim of this paper is to present the basic elements of CAOS devices and to review state-of-the-art examples of different imaging modalities used to create the virtual representations, of different position tracking devices for navigation systems, of different surgical robots, of different methods for registration and referencing, and of CAOS modules that have been realized for different surgical procedures. Future perspectives will also be outlined.

  20. Accelerating Climate Simulations Through Hybrid Computing

    Science.gov (United States)

    Zhou, Shujia; Sinno, Scott; Cruz, Carlos; Purcell, Mark

    2009-01-01

    Unconventional multi-core processors (e.g., IBM Cell B/E and NYIDIDA GPU) have emerged as accelerators in climate simulation. However, climate models typically run on parallel computers with conventional processors (e.g., Intel and AMD) using MPI. Connecting accelerators to this architecture efficiently and easily becomes a critical issue. When using MPI for connection, we identified two challenges: (1) identical MPI implementation is required in both systems, and; (2) existing MPI code must be modified to accommodate the accelerators. In response, we have extended and deployed IBM Dynamic Application Virtualization (DAV) in a hybrid computing prototype system (one blade with two Intel quad-core processors, two IBM QS22 Cell blades, connected with Infiniband), allowing for seamlessly offloading compute-intensive functions to remote, heterogeneous accelerators in a scalable, load-balanced manner. Currently, a climate solar radiation model running with multiple MPI processes has been offloaded to multiple Cell blades with approx.10% network overhead.

  1. Computer simulation of high energy displacement cascades

    International Nuclear Information System (INIS)

    Heinisch, H.L.

    1990-01-01

    A methodology developed for modeling many aspects of high energy displacement cascades with molecular level computer simulations is reviewed. The initial damage state is modeled in the binary collision approximation (using the MARLOWE computer code), and the subsequent disposition of the defects within a cascade is modeled with a Monte Carlo annealing simulation (the ALSOME code). There are few adjustable parameters, and none are set to physically unreasonable values. The basic configurations of the simulated high energy cascades in copper, i.e., the number, size and shape of damage regions, compare well with observations, as do the measured numbers of residual defects and the fractions of freely migrating defects. The success of these simulations is somewhat remarkable, given the relatively simple models of defects and their interactions that are employed. The reason for this success is that the behavior of the defects is very strongly influenced by their initial spatial distributions, which the binary collision approximation adequately models. The MARLOWE/ALSOME system, with input from molecular dynamics and experiments, provides a framework for investigating the influence of high energy cascades on microstructure evolution. (author)

  2. Computer simulation in nuclear science and engineering

    International Nuclear Information System (INIS)

    Akiyama, Mamoru; Miya, Kenzo; Iwata, Shuichi; Yagawa, Genki; Kondo, Shusuke; Hoshino, Tsutomu; Shimizu, Akinao; Takahashi, Hiroshi; Nakagawa, Masatoshi.

    1992-01-01

    The numerical simulation technology used for the design of nuclear reactors includes the scientific fields of wide range, and is the cultivated technology which grew in the steady efforts to high calculation accuracy through safety examination, reliability verification test, the assessment of operation results and so on. Taking the opportunity of putting numerical simulation to practical use in wide fields, the numerical simulation of five basic equations which describe the natural world and the progress of its related technologies are reviewed. It is expected that numerical simulation technology contributes to not only the means of design study but also the progress of science and technology such as the construction of new innovative concept, the exploration of new mechanisms and substances, of which the models do not exist in the natural world. The development of atomic energy and the progress of computers, Boltzmann's transport equation and its periphery, Navier-Stokes' equation and its periphery, Maxwell's electromagnetic field equation and its periphery, Schroedinger wave equation and its periphery, computational solid mechanics and its periphery, and probabilistic risk assessment and its periphery are described. (K.I.)

  3. Computer simulation for sodium-concrete reactions

    International Nuclear Information System (INIS)

    Zhang Bin; Zhu Jizhou

    2006-01-01

    In the liquid metal cooled fast breeder reactors (LMFBRs), direct contacts between sodium and concrete is unavoidable. Due to sodium's high chemical reactivity, sodium would react with concrete violently. Lots of hydrogen gas and heat would be released then. This would harm the ignorantly of the containment. This paper developed a program to simualte sodium-conrete reactions across-the-board. It could give the reaction zone temperature, pool temperature, penetration depth, penetration rate, hydrogen flux and reaction heat and so on. Concrete was considered to be composed of silica and water only in this paper. The variable, the quitient of sodium hydroxide, was introduced in the continuity equation to simulate the chemical reactions more realistically. The product of the net gas flux and boundary depth was ably transformed to that of penetration rate and boundary depth. The complex chemical kinetics equations was simplified under some hypothesises. All the technique applied above simplified the computer simulation consumedly. In other words, they made the computer simulation feasible. Theoretics models that applied in the program and the calculation procedure were expatiated in detail. Good agreements of an overall transient behavior were obtained in the series of sodium-concrete reaction experiment analysis. The comparison between the analytical and experimental results showed the program presented in this paper was creditable and reasonable for simulating the sodium-concrete reactions. This program could be used for nuclear safety judgement. (authors)

  4. HTTR plant dynamic simulation using a hybrid computer

    International Nuclear Information System (INIS)

    Shimazaki, Junya; Suzuki, Katsuo; Nabeshima, Kunihiko; Watanabe, Koichi; Shinohara, Yoshikuni; Nakagawa, Shigeaki.

    1990-01-01

    A plant dynamic simulation of High-Temperature Engineering Test Reactor has been made using a new-type hybrid computer. This report describes a dynamic simulation model of HTTR, a hybrid simulation method for SIMSTAR and some results obtained from dynamics analysis of HTTR simulation. It concludes that the hybrid plant simulation is useful for on-line simulation on account of its capability of computation at high speed, compared with that of all digital computer simulation. With sufficient accuracy, 40 times faster computation than real time was reached only by changing an analog time scale for HTTR simulation. (author)

  5. A haptic interface for virtual simulation of endoscopic surgery.

    Science.gov (United States)

    Rosenberg, L B; Stredney, D

    1996-01-01

    Virtual reality can be described as a convincingly realistic and naturally interactive simulation in which the user is given a first person illusion of being immersed within a computer generated environment While virtual reality systems offer great potential to reduce the cost and increase the quality of medical training, many technical challenges must be overcome before such simulation platforms offer effective alternatives to more traditional training means. A primary challenge in developing effective virtual reality systems is designing the human interface hardware which allows rich sensory information to be presented to users in natural ways. When simulating a given manual procedure, task specific human interface requirements dictate task specific human interface hardware. The following paper explores the design of human interface hardware that satisfies the task specific requirements of virtual reality simulation of Endoscopic surgical procedures. Design parameters were derived through direct cadaver studies and interviews with surgeons. Final hardware design is presented.

  6. Automatic Model Generation Framework for Computational Simulation of Cochlear Implantation.

    Science.gov (United States)

    Mangado, Nerea; Ceresa, Mario; Duchateau, Nicolas; Kjer, Hans Martin; Vera, Sergio; Dejea Velardo, Hector; Mistrik, Pavel; Paulsen, Rasmus R; Fagertun, Jens; Noailly, Jérôme; Piella, Gemma; González Ballester, Miguel Ángel

    2016-08-01

    Recent developments in computational modeling of cochlear implantation are promising to study in silico the performance of the implant before surgery. However, creating a complete computational model of the patient's anatomy while including an external device geometry remains challenging. To address such a challenge, we propose an automatic framework for the generation of patient-specific meshes for finite element modeling of the implanted cochlea. First, a statistical shape model is constructed from high-resolution anatomical μCT images. Then, by fitting the statistical model to a patient's CT image, an accurate model of the patient-specific cochlea anatomy is obtained. An algorithm based on the parallel transport frame is employed to perform the virtual insertion of the cochlear implant. Our automatic framework also incorporates the surrounding bone and nerve fibers and assigns constitutive parameters to all components of the finite element model. This model can then be used to study in silico the effects of the electrical stimulation of the cochlear implant. Results are shown on a total of 25 models of patients. In all cases, a final mesh suitable for finite element simulations was obtained, in an average time of 94 s. The framework has proven to be fast and robust, and is promising for a detailed prognosis of the cochlear implantation surgery.

  7. Flow and air conditioning simulations of computer turbinectomized nose models.

    Science.gov (United States)

    Pérez-Mota, J; Solorio-Ordaz, F; Cervantes-de Gortari, J

    2018-04-16

    Air conditioning for the human respiratory system is the most important function of the nose. When obstruction occurs in the nasal airway, turbinectomy is used to correct such pathology. However, mucosal atrophy may occur sometime after this surgery when it is overdone. There is not enough information about long-term recovery of nasal air conditioning performance after partial or total surgery. The purpose of this research was to assess if, based on the flow and temperature/humidity characteristics of the air intake to the choana, partial resection of turbinates is better than total resection. A normal nasal cavity geometry was digitized from tomographic scans and a model was printed in 3D. Dynamic (sinusoidal) laboratory tests and computer simulations of airflow were conducted with full agreement between numerical and experimental results. Computational adaptations were subsequently performed to represent six turbinectomy variations and a swollen nasal cavity case. Streamlines along the nasal cavity and temperature and humidity distributions at the choana indicated that the middle turbinate partial resection is the best alternative. These findings may facilitate the diagnosis of nasal obstruction and can be useful both to plan a turbinectomy and to reduce postoperative discomfort. Graphical Abstract ᅟ.

  8. 3D-printed pediatric endoscopic ear surgery simulator for surgical training.

    Science.gov (United States)

    Barber, Samuel R; Kozin, Elliott D; Dedmon, Matthew; Lin, Brian M; Lee, Kyuwon; Sinha, Sumi; Black, Nicole; Remenschneider, Aaron K; Lee, Daniel J

    2016-11-01

    Surgical simulators are designed to improve operative skills and patient safety. Transcanal Endoscopic Ear Surgery (TEES) is a relatively new surgical approach with a slow learning curve due to one-handed dissection. A reusable and customizable 3-dimensional (3D)-printed endoscopic ear surgery simulator may facilitate the development of surgical skills with high fidelity and low cost. Herein, we aim to design, fabricate, and test a low-cost and reusable 3D-printed TEES simulator. The TEES simulator was designed in computer-aided design (CAD) software using anatomic measurements taken from anthropometric studies. Cross sections from external auditory canal samples were traced as vectors and serially combined into a mesh construct. A modified tympanic cavity with a modular testing platform for simulator tasks was incorporated. Components were fabricated using calcium sulfate hemihydrate powder and multiple colored infiltrants via a commercial inkjet 3D-printing service. All components of a left-sided ear were printed to scale. Six right-handed trainees completed three trials each. Mean trial time (n = 3) ranged from 23.03 to 62.77 s using the dominant hand for all dissection. Statistically significant differences between first and last completion time with the dominant hand (p 3D-printed simulator is feasible for TEES simulation. Otolaryngology training programs with access to a 3D printer may readily fabricate a TEES simulator, resulting in inexpensive yet high-fidelity surgical simulation. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  9. Computer simulation games in population and education.

    Science.gov (United States)

    Moreland, R S

    1988-01-01

    Computer-based simulation games are effective training tools that have several advantages. They enable players to learn in a nonthreatening manner and develop strategies to achieve goals in a dynamic environment. They also provide visual feedback on the effects of players' decisions, encourage players to explore and experiment with options before making final decisions, and develop players' skills in analysis, decision making, and cooperation. 2 games have been developed by the Research Triangle Institute for public-sector planning agencies interested in or dealing with developing countries. The UN Population and Development Game teaches players about the interaction between population variables and the national economy and how population policies complement other national policies, such as education. The BRIDGES Education Planning Game focuses on the effects education has on national policies. In both games, the computer simulates the reactions of a fictional country's socioeconomic system to players' decisions. Players can change decisions after seeing their effects on a computer screen and thus can improve their performance in achieving goals.

  10. New Computer Simulations of Macular Neural Functioning

    Science.gov (United States)

    Ross, Muriel D.; Doshay, D.; Linton, S.; Parnas, B.; Montgomery, K.; Chimento, T.

    1994-01-01

    We use high performance graphics workstations and supercomputers to study the functional significance of the three-dimensional (3-D) organization of gravity sensors. These sensors have a prototypic architecture foreshadowing more complex systems. Scaled-down simulations run on a Silicon Graphics workstation and scaled-up, 3-D versions run on a Cray Y-MP supercomputer. A semi-automated method of reconstruction of neural tissue from serial sections studied in a transmission electron microscope has been developed to eliminate tedious conventional photography. The reconstructions use a mesh as a step in generating a neural surface for visualization. Two meshes are required to model calyx surfaces. The meshes are connected and the resulting prisms represent the cytoplasm and the bounding membranes. A finite volume analysis method is employed to simulate voltage changes along the calyx in response to synapse activation on the calyx or on calyceal processes. The finite volume method insures that charge is conserved at the calyx-process junction. These and other models indicate that efferent processes act as voltage followers, and that the morphology of some afferent processes affects their functioning. In a final application, morphological information is symbolically represented in three dimensions in a computer. The possible functioning of the connectivities is tested using mathematical interpretations of physiological parameters taken from the literature. Symbolic, 3-D simulations are in progress to probe the functional significance of the connectivities. This research is expected to advance computer-based studies of macular functioning and of synaptic plasticity.

  11. Simulation and computation in health physics training

    International Nuclear Information System (INIS)

    Lakey, S.R.A.; Gibbs, D.C.C.; Marchant, C.P.

    1980-01-01

    The Royal Naval College has devised a number of computer aided learning programmes applicable to health physics which include radiation shield design and optimisation, environmental impact of a reactor accident, exposure levels produced by an inert radioactive gas cloud, and the prediction of radiation detector response in various radiation field conditions. Analogue computers are used on reduced or fast time scales because time dependent phenomenon are not always easily assimilated in real time. The build-up and decay of fission products, the dynamics of intake of radioactive material and reactor accident dynamics can be effectively simulated. It is essential to relate these simulations to real time and the College applies a research reactor and analytical phantom to this end. A special feature of the reactor is a chamber which can be supplied with Argon-41 from reactor exhaust gases to create a realistic gaseous contamination environment. Reactor accident situations are also taught by using role playing sequences carried out in real time in the emergency facilities associated with the research reactor. These facilities are outlined and the training technique illustrated with examples of the calculations and simulations. The training needs of the future are discussed, with emphasis on optimisation and cost-benefit analysis. (H.K.)

  12. [Clinical analysis of 12 cases of orthognathic surgery with digital computer-assisted technique].

    Science.gov (United States)

    Tan, Xin-ying; Hu, Min; Liu, Chang-kui; Liu, Hua-wei; Liu, San-xia; Tao, Ye

    2014-06-01

    This study was to investigate the effect of the digital computer-assisted technique in orthognathic surgery. Twelve patients from January 2008 to December 2011 with jaw malformation were treated in our department. With the help of CT and three-dimensional reconstruction technique, 12 patients underwent surgical treatment and the results were evaluated after surgery. Digital computer-assisted technique could clearly show the status of the jaw deformity and assist virtual surgery. After surgery all patients were satisfied with the results. Digital orthognathic surgery can improve the predictability of the surgical procedure, and to facilitate patients' communication, shorten operative time, and reduce patients' pain.

  13. Modular multiple sensors information management for computer-integrated surgery.

    Science.gov (United States)

    Vaccarella, Alberto; Enquobahrie, Andinet; Ferrigno, Giancarlo; Momi, Elena De

    2012-09-01

    In the past 20 years, technological advancements have modified the concept of modern operating rooms (ORs) with the introduction of computer-integrated surgery (CIS) systems, which promise to enhance the outcomes, safety and standardization of surgical procedures. With CIS, different types of sensor (mainly position-sensing devices, force sensors and intra-operative imaging devices) are widely used. Recently, the need for a combined use of different sensors raised issues related to synchronization and spatial consistency of data from different sources of information. In this study, we propose a centralized, multi-sensor management software architecture for a distributed CIS system, which addresses sensor information consistency in both space and time. The software was developed as a data server module in a client-server architecture, using two open-source software libraries: Image-Guided Surgery Toolkit (IGSTK) and OpenCV. The ROBOCAST project (FP7 ICT 215190), which aims at integrating robotic and navigation devices and technologies in order to improve the outcome of the surgical intervention, was used as the benchmark. An experimental protocol was designed in order to prove the feasibility of a centralized module for data acquisition and to test the application latency when dealing with optical and electromagnetic tracking systems and ultrasound (US) imaging devices. Our results show that a centralized approach is suitable for minimizing synchronization errors; latency in the client-server communication was estimated to be 2 ms (median value) for tracking systems and 40 ms (median value) for US images. The proposed centralized approach proved to be adequate for neurosurgery requirements. Latency introduced by the proposed architecture does not affect tracking system performance in terms of frame rate and limits US images frame rate at 25 fps, which is acceptable for providing visual feedback to the surgeon in the OR. Copyright © 2012 John Wiley & Sons, Ltd.

  14. Computer simulation of spacecraft/environment interaction

    International Nuclear Information System (INIS)

    Krupnikov, K.K.; Makletsov, A.A.; Mileev, V.N.; Novikov, L.S.; Sinolits, V.V.

    1999-01-01

    This report presents some examples of a computer simulation of spacecraft interaction with space environment. We analysed a set data on electron and ion fluxes measured in 1991-1994 on geostationary satellite GORIZONT-35. The influence of spacecraft eclipse and device eclipse by solar-cell panel on spacecraft charging was investigated. A simple method was developed for an estimation of spacecraft potentials in LEO. Effects of various particle flux impact and spacecraft orientation are discussed. A computer engineering model for a calculation of space radiation is presented. This model is used as a client/server model with WWW interface, including spacecraft model description and results representation based on the virtual reality markup language

  15. Computer simulation of spacecraft/environment interaction

    CERN Document Server

    Krupnikov, K K; Mileev, V N; Novikov, L S; Sinolits, V V

    1999-01-01

    This report presents some examples of a computer simulation of spacecraft interaction with space environment. We analysed a set data on electron and ion fluxes measured in 1991-1994 on geostationary satellite GORIZONT-35. The influence of spacecraft eclipse and device eclipse by solar-cell panel on spacecraft charging was investigated. A simple method was developed for an estimation of spacecraft potentials in LEO. Effects of various particle flux impact and spacecraft orientation are discussed. A computer engineering model for a calculation of space radiation is presented. This model is used as a client/server model with WWW interface, including spacecraft model description and results representation based on the virtual reality markup language.

  16. Computer simulations of a rough sphere fluid

    International Nuclear Information System (INIS)

    Lyklema, J.W.

    1978-01-01

    A computer simulation is described on rough hard spheres with a continuously variable roughness parameter, including the limits of smooth and completely rough spheres. A system of 500 particles is simulated with a homogeneous mass distribution at 8 different densities and for 5 different values of the roughness parameter. For these 40 physically different situations the intermediate scattering function for 6 values of the wave number, the orientational correlation functions and the velocity autocorrelation functions have been calculated. A comparison has been made with a neutron scattering experiment on neopentane and agreement was good for an intermediate value of the roughness parameter. Some often made approximations in neutron scattering experiments are also checked. The influence of the variable roughness parameter on the correlation functions has been investigated and three simple stochastic models studied to describe the orientational correlation function which shows the most pronounced dependence on the roughness. (Auth.)

  17. Computer Simulation of Multidimensional Archaeological Artefacts

    Directory of Open Access Journals (Sweden)

    Vera Moitinho de Almeida

    2013-11-01

    Full Text Available The main purpose of this ongoing research is to understand possible function(s of archaeological artefacts through Reverse Engineering processes. In addition, we intend to provide new data, as well as possible explications of the archaeological record according to what it expects about social activities and working processes, by simulating the potentialities of such actions in terms of input-output relationships. Our project focuses on the Neolithic lakeside site of La Draga (Banyoles, Catalonia. In this presentation we will begin by providing a clear overview of the major guidelines used to capture and process 3D digital data of several wooden artefacts. Then, we shall present the use of semi-automated relevant feature extractions. Finally, we intend to share preliminary computer simulation issues.

  18. Computational simulation of the blood separation process.

    Science.gov (United States)

    De Gruttola, Sandro; Boomsma, Kevin; Poulikakos, Dimos; Ventikos, Yiannis

    2005-08-01

    The aim of this work is to construct a computational fluid dynamics model capable of simulating the quasitransient process of apheresis. To this end a Lagrangian-Eulerian model has been developed which tracks the blood particles within a delineated two-dimensional flow domain. Within the Eulerian method, the fluid flow conservation equations within the separator are solved. Taking the calculated values of the flow field and using a Lagrangian method, the displacement of the blood particles is calculated. Thus, the local blood density within the separator at a given time step is known. Subsequently, the flow field in the separator is recalculated. This process continues until a quasisteady behavior is reached. The simulations show good agreement with experimental results. They shows a complete separation of plasma and red blood cells, as well as nearly complete separation of red blood cells and platelets. The white blood cells build clusters in the low concentrate cell bed.

  19. A computer simulation of auger electron spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ragheb, M S; Bakr, M H.S. [Dept. Of Accellerators and Ion Sources, Division of Basic Nuclear Sciences, NRC, Atomic Energy Authority, (Egypt)

    1997-12-31

    A simulation study of Auger electron spectroscopy was performed to reveal how far the dependency between the different parameters governing the experimental behavior affects the peaks. The experimental procedure followed by the AC modulation technique were reproduced by means of a computer program. It generates the assumed output Auger electron peaks, exposes them to a retarding AC modulated field and collects the resulting modulated signals. The program produces the lock-in treatment in order to demodulate the signals revealing the Auger peaks. It analyzes the spectrum obtained giving the peak positions and energies. Comparison between results of simulation and the experimental data showed good agreement. The peaks of the spectrum obtained depend upon the amplitude, frequency and resolution of the applied modulated signal. The peak shape is effected by the rise time, the slope and the starting potential of the retarding field. 4 figs.

  20. Computer simulations of phospholipid - membrane thermodynamic fluctuations

    DEFF Research Database (Denmark)

    Pedersen, U.R.; Peters, Günther H.j.; Schröder, T.B.

    2008-01-01

    This paper reports all-atom computer simulations of five phospholipid membranes, DMPC, DPPC, DMPG, DMPS, and DMPSH, with a focus on the thermal equilibrium fluctuations of volume, energy, area, thickness, and order parameter. For the slow fluctuations at constant temperature and pressure (defined...... membranes, showing a similar picture. The cause of the observed strong correlations is identified by splitting volume and energy into contributions from tails, heads, and water, showing that the slow volume-energy fluctuations derive from the tail region’s van der Waals interactions and are thus analogous...

  1. Computer simulation of replacement sequences in copper

    International Nuclear Information System (INIS)

    Schiffgens, J.O.; Schwartz, D.W.; Ariyasu, R.G.; Cascadden, S.E.

    1978-01-01

    Results of computer simulations of , , and replacement sequences in copper are presented, including displacement thresholds, focusing energies, energy losses per replacement, and replacement sequence lengths. These parameters are tabulated for six interatomic potentials and shown to vary in a systematic way with potential stiffness and range. Comparisons of results from calculations made with ADDES, a quasi-dynamical code, and COMENT, a dynamical code, show excellent agreement, demonstrating that the former can be calibrated and used satisfactorily in the analysis of low energy displacement cascades. Upper limits on , , and replacement sequences were found to be approximately 10, approximately 30, and approximately 14 replacements, respectively. (author)

  2. 76 FR 71980 - SEDASYS Computer-Assisted Personalized Sedation System; Ethicon Endo-Surgery, Incorporated's...

    Science.gov (United States)

    2011-11-21

    ... DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and Drug Administration [Docket No. FDA-2010-P-0176] SEDASYS Computer-Assisted Personalized Sedation System; Ethicon Endo-Surgery, Incorporated's Petition for... SEDASYS computer-assisted personalized sedation system (SEDASYS) submitted by Ethicon Endo-Surgery Inc...

  3. Fundamentals of force feedback and application to a surgery simulator.

    Science.gov (United States)

    Maass, Heiko; Chantier, Benjamin B A; Cakmak, Hueseyin K; Trantakis, Christos; Kuehnapfel, Uwe G

    2003-01-01

    Force feedback increases the effectiveness of virtual-reality surgery training systems. An overview of the fundamentals of applying force feedback is presented. An impedance control technique and data processing methods for stability preservation are illustrated. A flexible interface for general force-feedback applications has been developed. This interface is capable of controlling several different force-feedback hardware systems, including the SensAble PHANTOM, the Laparoscopic Impulse Engines from Immersion, and the VS-One virtual endoscopic surgery trainer. The findings are evaluated using the main simulation system, KISMET, and the modeling tools KISMO and VESUV. Within the scope of a cooperative project called HapticIO (funded by the German Ministry of Education and Research [BMBF]), new haptic devices have been designed for virtual neuroendoscopy and laparoscopy. The concept and implementations presented in this paper have been found to be flexible, stable and suitable for universal use. The impedance method, combined with the open-loop feed-forward control technique, is well suited and appropriate for the task.

  4. Development of customized positioning guides using computer-aided design and manufacturing technology for orthognathic surgery.

    Science.gov (United States)

    Lin, Hsiu-Hsia; Chang, Hsin-Wen; Lo, Lun-Jou

    2015-12-01

    The purpose of this study was to devise a method for producing customized positioning guides for translating virtual plans to actual orthognathic surgery, and evaluation of the feasibility and validity of the devised method. Patients requiring two-jaw orthognathic surgery were enrolled and consented before operation. Two types of positioning guides were designed and fabricated using computer-aided design and manufacturing technology: One of the guides was used for the LeFort I osteotomy, and the other guide was used for positioning the maxillomandibular complex. The guides were fixed to the medial side of maxilla. For validation, the simulation images and postoperative cone beam computed tomography images were superimposed using surface registration to quantify the difference between the images. The data were presented in root-mean-square difference (RMSD) values. Both sets of guides were experienced to provide ideal fit and maximal contact to the maxillary surface to facilitate their accurate management in clinical applications. The validation results indicated that RMSD values between the images ranged from 0.18 to 0.33 mm in the maxilla and from 0.99 to 1.56 mm in the mandible. The patients were followed up for 6 months or more, and all of them were satisfied with the results. The proposed customized positioning guides are practical and reliable for translation of virtual plans to actual surgery. Furthermore, these guides improved the efficiency and outcome of surgery. This approach is uncomplicated in design, cost-effective in fabrication, and particularly convenient to use.

  5. Computational simulation of concurrent engineering for aerospace propulsion systems

    Science.gov (United States)

    Chamis, C. C.; Singhal, S. N.

    1992-01-01

    Results are summarized of an investigation to assess the infrastructure available and the technology readiness in order to develop computational simulation methods/software for concurrent engineering. These results demonstrate that development of computational simulations methods for concurrent engineering is timely. Extensive infrastructure, in terms of multi-discipline simulation, component-specific simulation, system simulators, fabrication process simulation, and simulation of uncertainties - fundamental in developing such methods, is available. An approach is recommended which can be used to develop computational simulation methods for concurrent engineering for propulsion systems and systems in general. Benefits and facets needing early attention in the development are outlined.

  6. Computational simulation for concurrent engineering of aerospace propulsion systems

    Science.gov (United States)

    Chamis, C. C.; Singhal, S. N.

    1993-01-01

    Results are summarized for an investigation to assess the infrastructure available and the technology readiness in order to develop computational simulation methods/software for concurrent engineering. These results demonstrate that development of computational simulation methods for concurrent engineering is timely. Extensive infrastructure, in terms of multi-discipline simulation, component-specific simulation, system simulators, fabrication process simulation, and simulation of uncertainties--fundamental to develop such methods, is available. An approach is recommended which can be used to develop computational simulation methods for concurrent engineering of propulsion systems and systems in general. Benefits and issues needing early attention in the development are outlined.

  7. A Computational Framework for Bioimaging Simulation

    Science.gov (United States)

    Watabe, Masaki; Arjunan, Satya N. V.; Fukushima, Seiya; Iwamoto, Kazunari; Kozuka, Jun; Matsuoka, Satomi; Shindo, Yuki; Ueda, Masahiro; Takahashi, Koichi

    2015-01-01

    Using bioimaging technology, biologists have attempted to identify and document analytical interpretations that underlie biological phenomena in biological cells. Theoretical biology aims at distilling those interpretations into knowledge in the mathematical form of biochemical reaction networks and understanding how higher level functions emerge from the combined action of biomolecules. However, there still remain formidable challenges in bridging the gap between bioimaging and mathematical modeling. Generally, measurements using fluorescence microscopy systems are influenced by systematic effects that arise from stochastic nature of biological cells, the imaging apparatus, and optical physics. Such systematic effects are always present in all bioimaging systems and hinder quantitative comparison between the cell model and bioimages. Computational tools for such a comparison are still unavailable. Thus, in this work, we present a computational framework for handling the parameters of the cell models and the optical physics governing bioimaging systems. Simulation using this framework can generate digital images of cell simulation results after accounting for the systematic effects. We then demonstrate that such a framework enables comparison at the level of photon-counting units. PMID:26147508

  8. Computer simulations for the nano-scale

    International Nuclear Information System (INIS)

    Stich, I.

    2007-01-01

    A review of methods for computations for the nano-scale is presented. The paper should provide a convenient starting point into computations for the nano-scale as well as a more in depth presentation for those already working in the field of atomic/molecular-scale modeling. The argument is divided in chapters covering the methods for description of the (i) electrons, (ii) ions, and (iii) techniques for efficient solving of the underlying equations. A fairly broad view is taken covering the Hartree-Fock approximation, density functional techniques and quantum Monte-Carlo techniques for electrons. The customary quantum chemistry methods, such as post Hartree-Fock techniques, are only briefly mentioned. Description of both classical and quantum ions is presented. The techniques cover Ehrenfest, Born-Oppenheimer, and Car-Parrinello dynamics. The strong and weak points of both principal and technical nature are analyzed. In the second part we introduce a number of applications to demonstrate the different approximations and techniques introduced in the first part. They cover a wide range of applications such as non-simple liquids, surfaces, molecule-surface interactions, applications in nano technology, etc. These more in depth presentations, while certainly not exhaustive, should provide information on technical aspects of the simulations, typical parameters used, and ways of analysis of the huge amounts of data generated in these large-scale supercomputer simulations. (author)

  9. Reproducibility in Computational Neuroscience Models and Simulations

    Science.gov (United States)

    McDougal, Robert A.; Bulanova, Anna S.; Lytton, William W.

    2016-01-01

    Objective Like all scientific research, computational neuroscience research must be reproducible. Big data science, including simulation research, cannot depend exclusively on journal articles as the method to provide the sharing and transparency required for reproducibility. Methods Ensuring model reproducibility requires the use of multiple standard software practices and tools, including version control, strong commenting and documentation, and code modularity. Results Building on these standard practices, model sharing sites and tools have been developed that fit into several categories: 1. standardized neural simulators, 2. shared computational resources, 3. declarative model descriptors, ontologies and standardized annotations; 4. model sharing repositories and sharing standards. Conclusion A number of complementary innovations have been proposed to enhance sharing, transparency and reproducibility. The individual user can be encouraged to make use of version control, commenting, documentation and modularity in development of models. The community can help by requiring model sharing as a condition of publication and funding. Significance Model management will become increasingly important as multiscale models become larger, more detailed and correspondingly more difficult to manage by any single investigator or single laboratory. Additional big data management complexity will come as the models become more useful in interpreting experiments, thus increasing the need to ensure clear alignment between modeling data, both parameters and results, and experiment. PMID:27046845

  10. A Computational Framework for Bioimaging Simulation.

    Science.gov (United States)

    Watabe, Masaki; Arjunan, Satya N V; Fukushima, Seiya; Iwamoto, Kazunari; Kozuka, Jun; Matsuoka, Satomi; Shindo, Yuki; Ueda, Masahiro; Takahashi, Koichi

    2015-01-01

    Using bioimaging technology, biologists have attempted to identify and document analytical interpretations that underlie biological phenomena in biological cells. Theoretical biology aims at distilling those interpretations into knowledge in the mathematical form of biochemical reaction networks and understanding how higher level functions emerge from the combined action of biomolecules. However, there still remain formidable challenges in bridging the gap between bioimaging and mathematical modeling. Generally, measurements using fluorescence microscopy systems are influenced by systematic effects that arise from stochastic nature of biological cells, the imaging apparatus, and optical physics. Such systematic effects are always present in all bioimaging systems and hinder quantitative comparison between the cell model and bioimages. Computational tools for such a comparison are still unavailable. Thus, in this work, we present a computational framework for handling the parameters of the cell models and the optical physics governing bioimaging systems. Simulation using this framework can generate digital images of cell simulation results after accounting for the systematic effects. We then demonstrate that such a framework enables comparison at the level of photon-counting units.

  11. A Computational Framework for Bioimaging Simulation.

    Directory of Open Access Journals (Sweden)

    Masaki Watabe

    Full Text Available Using bioimaging technology, biologists have attempted to identify and document analytical interpretations that underlie biological phenomena in biological cells. Theoretical biology aims at distilling those interpretations into knowledge in the mathematical form of biochemical reaction networks and understanding how higher level functions emerge from the combined action of biomolecules. However, there still remain formidable challenges in bridging the gap between bioimaging and mathematical modeling. Generally, measurements using fluorescence microscopy systems are influenced by systematic effects that arise from stochastic nature of biological cells, the imaging apparatus, and optical physics. Such systematic effects are always present in all bioimaging systems and hinder quantitative comparison between the cell model and bioimages. Computational tools for such a comparison are still unavailable. Thus, in this work, we present a computational framework for handling the parameters of the cell models and the optical physics governing bioimaging systems. Simulation using this framework can generate digital images of cell simulation results after accounting for the systematic effects. We then demonstrate that such a framework enables comparison at the level of photon-counting units.

  12. A Review of Freely Available Quantum Computer Simulation Software

    OpenAIRE

    Brandhorst-Satzkorn, Johan

    2012-01-01

    A study has been made of a few different freely available Quantum Computer simulators. All the simulators tested are available online on their respective websites. A number of tests have been performed to compare the different simulators against each other. Some untested simulators of various programming languages are included to show the diversity of the quantum computer simulator applications. The conclusion of the review is that LibQuantum is the best of the simulators tested because of ea...

  13. Computer Simulation of Developmental Processes and ...

    Science.gov (United States)

    Rationale: Recent progress in systems toxicology and synthetic biology have paved the way to new thinking about in vitro/in silico modeling of developmental processes and toxicities, both for embryological and reproductive impacts. Novel in vitro platforms such as 3D organotypic culture models, engineered microscale tissues and complex microphysiological systems (MPS), together with computational models and computer simulation of tissue dynamics, lend themselves to a integrated testing strategies for predictive toxicology. As these emergent methodologies continue to evolve, they must be integrally tied to maternal/fetal physiology and toxicity of the developing individual across early lifestage transitions, from fertilization to birth, through puberty and beyond. Scope: This symposium will focus on how the novel technology platforms can help now and in the future, with in vitro/in silico modeling of complex biological systems for developmental and reproductive toxicity issues, and translating systems models into integrative testing strategies. The symposium is based on three main organizing principles: (1) that novel in vitro platforms with human cells configured in nascent tissue architectures with a native microphysiological environments yield mechanistic understanding of developmental and reproductive impacts of drug/chemical exposures; (2) that novel in silico platforms with high-throughput screening (HTS) data, biologically-inspired computational models of

  14. A Computer Simulation of Auroral Arc Formation.

    Science.gov (United States)

    Wagner, John Scott

    Recent satellite measurements have revealed two intriguing features associated with the formation of auroral arcs. The first is that an auroral arc is produced by a sheet of electrons accelerated along a geomagnetic field -aligned potential drop, and the second is that these electrons carry a field-aligned, upward directed electric current. In order to explain these measurements, a self-consistent, time dependent, computer simulation of auroral arc formation has been developed. The simulation demonstrates for the first time that a stable V-shaped potential structure, called an auroral double layer, develops spontaneously as a result of an ion shielded electron current sheet interacting with a conducting ionosphere. The double layer accelerates current-carrying electrons into the upper atmosphere at auroral energies. The double layer potential depends critically on the drift speed of the current-carrying electrons and on the temperature of the ambient shielding ions. Localized double layers occur near the ionosphere when the geomagnetic field is assumed to be uniform, but when a converging magnetic field is introduced, the double layer becomes extended due to the presence of an additional population of electrons trapped between the magnetic mirror and the double layer potential. The simulated auroral current sheet is subject to auroral curl and fold type deformations due to unstable Kelvin-Helmholtz waves. The previous incompletely understood auroral fold producing mechanism is described.

  15. Computer simulation of fatigue under diametrical compression

    International Nuclear Information System (INIS)

    Carmona, H. A.; Kun, F.; Andrade, J. S. Jr.; Herrmann, H. J.

    2007-01-01

    We study the fatigue fracture of disordered materials by means of computer simulations of a discrete element model. We extend a two-dimensional fracture model to capture the microscopic mechanisms relevant for fatigue and we simulate the diametric compression of a disc shape specimen under a constant external force. The model allows us to follow the development of the fracture process on the macrolevel and microlevel varying the relative influence of the mechanisms of damage accumulation over the load history and healing of microcracks. As a specific example we consider recent experimental results on the fatigue fracture of asphalt. Our numerical simulations show that for intermediate applied loads the lifetime of the specimen presents a power law behavior. Under the effect of healing, more prominent for small loads compared to the tensile strength of the material, the lifetime of the sample increases and a fatigue limit emerges below which no macroscopic failure occurs. The numerical results are in a good qualitative agreement with the experimental findings

  16. Computer Simulation of the UMER Gridded Gun

    CERN Document Server

    Haber, Irving; Friedman, Alex; Grote, D P; Kishek, Rami A; Reiser, Martin; Vay, Jean-Luc; Zou, Yun

    2005-01-01

    The electron source in the University of Maryland Electron Ring (UMER) injector employs a grid 0.15 mm from the cathode to control the current waveform. Under nominal operating conditions, the grid voltage during the current pulse is sufficiently positive relative to the cathode potential to form a virtual cathode downstream of the grid. Three-dimensional computer simulations have been performed that use the mesh refinement capability of the WARP particle-in-cell code to examine a small region near the beam center in order to illustrate some of the complexity that can result from such a gridded structure. These simulations have been found to reproduce the hollowed velocity space that is observed experimentally. The simulations also predict a complicated time-dependent response to the waveform applied to the grid during the current turn-on. This complex temporal behavior appears to result directly from the dynamics of the virtual cathode formation and may therefore be representative of the expected behavior in...

  17. The current status and future prospects of computer-assisted hip surgery.

    Science.gov (United States)

    Inaba, Yutaka; Kobayashi, Naomi; Ike, Hiroyuki; Kubota, So; Saito, Tomoyuki

    2016-03-01

    The advances in computer assistance technology have allowed detailed three-dimensional preoperative planning and simulation of preoperative plans. The use of a navigation system as an intraoperative assistance tool allows more accurate execution of the preoperative plan, compared to manual operation without assistance of the navigation system. In total hip arthroplasty using CT-based navigation, three-dimensional preoperative planning with computer software allows the surgeon to determine the optimal angle of implant placement at which implant impingement is unlikely to occur in the range of hip joint motion necessary for daily activities of living, and to determine the amount of three-dimensional correction for leg length and offset. With the use of computer navigation for intraoperative assistance, the preoperative plan can be precisely executed. In hip osteotomy using CT-based navigation, the navigation allows three-dimensional preoperative planning, intraoperative confirmation of osteotomy sites, safe performance of osteotomy even under poor visual conditions, and a reduction in exposure doses from intraoperative fluoroscopy. Positions of the tips of chisels can be displayed on the computer monitor during surgery in real time, and staff other than the operator can also be aware of the progress of surgery. Thus, computer navigation also has an educational value. On the other hand, its limitations include the need for placement of trackers, increased radiation exposure from preoperative CT scans, and prolonged operative time. Moreover, because the position of a bone fragment cannot be traced after osteotomy, methods to find its precise position after its movement need to be developed. Despite the need to develop methods for the postoperative evaluation of accuracy for osteotomy, further application and development of these systems are expected in the future. Copyright © 2016 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.

  18. Cluster computing for lattice QCD simulations

    International Nuclear Information System (INIS)

    Coddington, P.D.; Williams, A.G.

    2000-01-01

    Full text: Simulations of lattice quantum chromodynamics (QCD) require enormous amounts of compute power. In the past, this has usually involved sharing time on large, expensive machines at supercomputing centres. Over the past few years, clusters of networked computers have become very popular as a low-cost alternative to traditional supercomputers. The dramatic improvements in performance (and more importantly, the ratio of price/performance) of commodity PCs, workstations, and networks have made clusters of off-the-shelf computers an attractive option for low-cost, high-performance computing. A major advantage of clusters is that since they can have any number of processors, they can be purchased using any sized budget, allowing research groups to install a cluster for their own dedicated use, and to scale up to more processors if additional funds become available. Clusters are now being built for high-energy physics simulations. Wuppertal has recently installed ALiCE, a cluster of 128 Alpha workstations running Linux, with a peak performance of 158 G flops. The Jefferson Laboratory in the US has a 16 node Alpha cluster and plans to upgrade to a 256 processor machine. In Australia, several large clusters have recently been installed. Swinburne University of Technology has a cluster of 64 Compaq Alpha workstations used for astrophysics simulations. Early this year our DHPC group constructed a cluster of 116 dual Pentium PCs (i.e. 232 processors) connected by a Fast Ethernet network, which is used by chemists at Adelaide University and Flinders University to run computational chemistry codes. The Australian National University has recently installed a similar PC cluster with 192 processors. The Centre for the Subatomic Structure of Matter (CSSM) undertakes large-scale high-energy physics calculations, mainly lattice QCD simulations. The choice of the computer and network hardware for a cluster depends on the particular applications to be run on the machine. Our

  19. Computer Simulation of Electron Positron Annihilation Processes

    Energy Technology Data Exchange (ETDEWEB)

    Chen, y

    2003-10-02

    With the launching of the Next Linear Collider coming closer and closer, there is a pressing need for physicists to develop a fully-integrated computer simulation of e{sup +}e{sup -} annihilation process at center-of-mass energy of 1TeV. A simulation program acts as the template for future experiments. Either new physics will be discovered, or current theoretical uncertainties will shrink due to more accurate higher-order radiative correction calculations. The existence of an efficient and accurate simulation will help us understand the new data and validate (or veto) some of the theoretical models developed to explain new physics. It should handle well interfaces between different sectors of physics, e.g., interactions happening at parton levels well above the QCD scale which are described by perturbative QCD, and interactions happening at much lower energy scale, which combine partons into hadrons. Also it should achieve competitive speed in real time when the complexity of the simulation increases. This thesis contributes some tools that will be useful for the development of such simulation programs. We begin our study by the development of a new Monte Carlo algorithm intended to perform efficiently in selecting weight-1 events when multiple parameter dimensions are strongly correlated. The algorithm first seeks to model the peaks of the distribution by features, adapting these features to the function using the EM algorithm. The representation of the distribution provided by these features is then improved using the VEGAS algorithm for the Monte Carlo integration. The two strategies mesh neatly into an effective multi-channel adaptive representation. We then present a new algorithm for the simulation of parton shower processes in high energy QCD. We want to find an algorithm which is free of negative weights, produces its output as a set of exclusive events, and whose total rate exactly matches the full Feynman amplitude calculation. Our strategy is to create

  20. Effect of music on surgical skill during simulated intraocular surgery.

    Science.gov (United States)

    Kyrillos, Ralph; Caissie, Mathieu

    2017-12-01

    To evaluate the effect of Mozart music compared to silence on anterior segment surgical skill in the context of simulated intraocular surgery. Prospective stratified and randomized noninferiority trial. Fourteen ophthalmologists and 12 residents in ophthalmology. All participants were asked to perform 4 sets of predetermined tasks on the EyeSI surgical simulator (VRmagic, Mannheim, Germany). The participants completed 1 Capsulorhexis task and 1 Anti-Tremor task during 3 separate visits. The first 2 sets determined the basic level on day 1. Then, the participants were stratified by surgical experience and randomized to be exposed to music (Mozart sonata for 2 pianos in D-K448) during either the third or the fourth set of tasks (day 2 or 3). Surgical skill was evaluated using the parameters recorded by the simulator such as "Total score" and "Time" for both tasks and task-specific parameters such as "Out of tolerance percentage" for the Anti-Tremor task and "Deviation of rhexis radius from 2.5 mm," "Roundness," and "Centering" for the Capsulorhexis task. The data were analyzed using the Wilcoxon signed-rank test. No statistically significant differences were noted between exposure and nonexposure for all the Anti-Tremor task parameters as well as most parameters for the Capsulorhexis task. Two parameters for the Capsulorhexis task showed a strong trend for improvement with exposure to music ("Total score" +23.3%, p = 0.025; "Roundness" +33.0%, p = 0.037). Exposure to music did not negatively impact surgical skills. Moreover, a trend for improvement was shown while listening to Mozart music. Copyright © 2017 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved.

  1. Computer simulation of probability of detection

    International Nuclear Information System (INIS)

    Fertig, K.W.; Richardson, J.M.

    1983-01-01

    This paper describes an integrated model for assessing the performance of a given ultrasonic inspection system for detecting internal flaws, where the performance of such a system is measured by probability of detection. The effects of real part geometries on sound propagations are accounted for and the noise spectra due to various noise mechanisms are measured. An ultrasonic inspection simulation computer code has been developed to be able to detect flaws with attributes ranging over an extensive class. The detection decision is considered to be a binary decision based on one received waveform obtained in a pulse-echo or pitch-catch setup. This study focuses on the detectability of flaws using an amplitude thresholding type. Some preliminary results on the detectability of radially oriented cracks in IN-100 for bore-like geometries are given

  2. Computer simulation of backscattered alpha particles

    International Nuclear Information System (INIS)

    Sanchez, A. Martin; Bland, C.J.; Timon, A. Fernandez

    2000-01-01

    Alpha-particle spectrometry forms an important aspect of radionuclide metrology. Accurate measurements require corrections to be made for factors such as self-absorption within the source and backscattering from the backing material. The theory of the latter phenomenon has only received limited attention. Furthermore the experimental verification of these theoretical results requires adequate counting statistics for a variety of sources with different activities. These problems could be resolved by computer simulations of the various interactions which occur as alpha-particles move through different materials. The pioneering work of Ziegler and his coworkers over several years, has provided the sophisticated software (SRIM) which has enabled us to obtain the results presented here. These results are compared with theoretical and experimental values obtained previously

  3. Computer simulation of a magnetohydrodynamic dynamo II

    International Nuclear Information System (INIS)

    Kageyama, Akira; Sato, Tetsuya.

    1994-11-01

    We performed a computer simulation of a magnetohydrodynamic dynamo in a rapidly rotating spherical shell. Extensive parameter runs are carried out changing the electrical resistivity. It is found that the total magnetic energy can grow more than ten times larger than the total kinetic energy of the convection motion when the resistivity is sufficiently small. When the resistivity is relatively large and the magnetic energy is comparable or smaller than the kinetic energy, the convection motion maintains its well-organized structure. However, when the resistivity is small and the magnetic energy becomes larger than the kinetic energy, the well-organized convection motion is highly disturbed. The generated magnetic field is organized as a set of flux tubes which can be divided into two categories. The magnetic field component parallel to the rotation axis tends to be confined inside the anticyclonic columnar convection cells. On the other hand, the component perpendicular to the rotation axis is confined outside the convection cells. (author)

  4. Amorphous nanoparticles — Experiments and computer simulations

    International Nuclear Information System (INIS)

    Hoang, Vo Van; Ganguli, Dibyendu

    2012-01-01

    The data obtained by both experiments and computer simulations concerning the amorphous nanoparticles for decades including methods of synthesis, characterization, structural properties, atomic mechanism of a glass formation in nanoparticles, crystallization of the amorphous nanoparticles, physico-chemical properties (i.e. catalytic, optical, thermodynamic, magnetic, bioactivity and other properties) and various applications in science and technology have been reviewed. Amorphous nanoparticles coated with different surfactants are also reviewed as an extension in this direction. Much attention is paid to the pressure-induced polyamorphism of the amorphous nanoparticles or amorphization of the nanocrystalline counterparts. We also introduce here nanocomposites and nanofluids containing amorphous nanoparticles. Overall, amorphous nanoparticles exhibit a disordered structure different from that of corresponding bulks or from that of the nanocrystalline counterparts. Therefore, amorphous nanoparticles can have unique physico-chemical properties differed from those of the crystalline counterparts leading to their potential applications in science and technology.

  5. Computer algebra simulation - what can it do?; Was leistet Computer-Algebra-Simulation?

    Energy Technology Data Exchange (ETDEWEB)

    Braun, S. [Visual Analysis AG, Muenchen (Germany)

    2001-07-01

    Shortened development times require new and improved calculation methods. Numeric methods have long become state of the art. However, although numeric simulations provide a better understanding of process parameters, they do not give a feast overview of the interdependences between parameters. Numeric simulations are effective only if all physical parameters are sufficiently known; otherwise, the efficiency will decrease due to the large number of variant calculations required. Computer algebra simulation closes this gap and provides a deeper understanding of the physical fundamentals of technical processes. [German] Neue und verbesserte Berechnungsmethoden sind notwendig, um die staendige Verkuerzung der Entwicklungszyklen zu ermoeglichen. Herkoemmliche Methoden, die auf einem rein numerischen Ansatz basieren, haben sich in vielen Anwendungsbereichen laengst zum Standard entwickelt. Aber nicht nur die staendig kuerzer werdenden Entwicklungszyklen, sondern auch die weiterwachsende Komplexitaet machen es notwendig, ein besseres Verstaendnis der beteiligten Prozessparameter zu gewinnen. Die numerische Simulation besticht zwar durch Detailloesungen, selbst bei komplexen Strukturen und Prozessen, allerdings liefert sie keine schnelle Abschaetzung ueber die Zusammenhaenge zwischen den einzelnen Parametern. Die numerische Simulation ist nur dann effektiv, wenn alle physikalischen Parameter hinreichend bekannt sind; andernfalls sinkt die Effizienz durch die notwendige Anzahl von notwendigen Variantenrechnungen sehr stark. Die Computer-Algebra-Simulation schliesst diese Luecke in dem sie es erlaubt, sich einen tieferen Einblick in die physikalische Funktionsweise technischer Prozesse zu verschaffen. (orig.)

  6. [Computer-assisted navigation in orthognathic surgery. Application to Le Fort I osteotomy.

    Science.gov (United States)

    Benassarou, M; Benassarou, A; Meyer, C

    2013-08-05

    Computer-assisted navigation is a tool that allows the surgeon to reach intraoperatively a previously defined target. This technique can be applied to the positioning of bone fragments in orthognathic surgery. It is not used routinely yet because there are no specifically dedicated systems available on the market for this kind of surgery. The goal of our study was to describe the various systems that could be used in orthognathic surgery and to report our experience of computer-assisted surgery in the positioning of the maxilla during maxillomandibular osteotomies. Copyright © 2013. Published by Elsevier Masson SAS.

  7. Step-based cognitive virtual surgery simulation: an innovative approach to surgical education.

    Science.gov (United States)

    Oliker, Aaron; Napier, Zachary; Deluccia, Nicolette; Qualter, John; Sculli, Frank; Smith, Brandon; Stern, Carrie; Flores, Roberto; Hazen, Alexes; McCarthy, Joseph

    2012-01-01

    BioDigital Systems, LLC in collaboration with New York University Langone Medical Center Department of Reconstructive Plastic Surgery has created a complex, real-time, step-based simulation platform for plastic surgery education. These simulators combine live surgical footage, interactive 3D visualization, text labels, and voiceover as well as a high-yield, expert-approved testing mode to create a comprehensive virtual educational environment for the plastic surgery resident or physician.

  8. Computer-Based Simulation Games in Public Administration Education

    OpenAIRE

    Kutergina Evgeniia

    2017-01-01

    Computer simulation, an active learning technique, is now one of the advanced pedagogical technologies. Th e use of simulation games in the educational process allows students to gain a firsthand understanding of the processes of real life. Public- administration, public-policy and political-science courses increasingly adopt simulation games in universities worldwide. Besides person-to-person simulation games, there are computer-based simulations in public-administration education. Currently...

  9. Computer simulation of dynamic processes on accelerators

    International Nuclear Information System (INIS)

    Kol'ga, V.V.

    1979-01-01

    The problems of computer numerical investigation of motion of accelerated particles in accelerators and storages, an effect of different accelerator systems on the motion, determination of optimal characteristics of accelerated charged particle beams are considered. Various simulation representations are discussed which describe the accelerated particle dynamics, such as the enlarged particle method, the representation where a great number of discrete particle is substituted for a field of continuously distributed space charge, the method based on determination of averaged beam characteristics. The procedure is described of numerical studies involving the basic problems, viz. calculation of closed orbits, establishment of stability regions, investigation of resonance propagation determination of the phase stability region, evaluation of the space charge effect the problem of beam extraction. It is shown that most of such problems are reduced to solution of the Cauchy problem using a computer. The ballistic method which is applied to solution of the boundary value problem of beam extraction is considered. It is shown that introduction into the equation under study of additional members with the small positive regularization parameter is a general idea of the methods for regularization of noncorrect problems [ru

  10. Associative Memory Computing Power and Its Simulation

    CERN Document Server

    Volpi, G; The ATLAS collaboration

    2014-01-01

    The associative memory (AM) system is a computing device made of hundreds of AM ASICs chips designed to perform “pattern matching” at very high speed. Since each AM chip stores a data base of 130000 pre-calculated patterns and large numbers of chips can be easily assembled together, it is possible to produce huge AM banks. Speed and size of the system are crucial for real-time High Energy Physics applications, such as the ATLAS Fast TracKer (FTK) Processor. Using 80 million channels of the ATLAS tracker, FTK finds tracks within 100 micro seconds. The simulation of such a parallelized system is an extremely complex task if executed in commercial computers based on normal CPUs. The algorithm performance is limited, due to the lack of parallelism, and in addition the memory requirement is very large. In fact the AM chip uses a content addressable memory (CAM) architecture. Any data inquiry is broadcast to all memory elements simultaneously, thus data retrieval time is independent of the database size. The gr...

  11. Associative Memory computing power and its simulation

    CERN Document Server

    Ancu, L S; The ATLAS collaboration; Britzger, D; Giannetti, P; Howarth, J W; Luongo, C; Pandini, C; Schmitt, S; Volpi, G

    2014-01-01

    The associative memory (AM) system is a computing device made of hundreds of AM ASICs chips designed to perform “pattern matching” at very high speed. Since each AM chip stores a data base of 130000 pre-calculated patterns and large numbers of chips can be easily assembled together, it is possible to produce huge AM banks. Speed and size of the system are crucial for real-time High Energy Physics applications, such as the ATLAS Fast TracKer (FTK) Processor. Using 80 million channels of the ATLAS tracker, FTK finds tracks within 100 micro seconds. The simulation of such a parallelized system is an extremely complex task if executed in commercial computers based on normal CPUs. The algorithm performance is limited, due to the lack of parallelism, and in addition the memory requirement is very large. In fact the AM chip uses a content addressable memory (CAM) architecture. Any data inquiry is broadcast to all memory elements simultaneously, thus data retrieval time is independent of the database size. The gr...

  12. Computer simulation of sputtering: A review

    International Nuclear Information System (INIS)

    Robinson, M.T.; Hou, M.

    1992-08-01

    In 1986, H. H. Andersen reviewed attempts to understand sputtering by computer simulation and identified several areas where further research was needed: potential energy functions for molecular dynamics (MD) modelling; the role of inelastic effects on sputtering, especially near the target surface; the modelling of surface binding in models based on the binary collision approximation (BCA); aspects of cluster emission in MD models; and angular distributions of sputtered particles. To these may be added kinetic energy distributions of sputtered particles and the relationships between MD and BCA models, as well as the development of intermediate models. Many of these topics are discussed. Recent advances in BCA modelling include the explicit evaluation of the time in strict BCA codes and the development of intermediate codes able to simulate certain many-particle problems realistically. Developments in MD modelling include the wide-spread use of many-body potentials in sputtering calculations, inclusion of realistic electron excitation and electron-phonon interactions, and several studies of cluster ion impacts on solid surfaces

  13. Computer simulations of the mouse spermatogenic cycle

    Directory of Open Access Journals (Sweden)

    Debjit Ray

    2014-12-01

    Full Text Available The spermatogenic cycle describes the periodic development of germ cells in the testicular tissue. The temporal–spatial dynamics of the cycle highlight the unique, complex, and interdependent interaction between germ and somatic cells, and are the key to continual sperm production. Although understanding the spermatogenic cycle has important clinical relevance for male fertility and contraception, there are a number of experimental obstacles. For example, the lengthy process cannot be visualized through dynamic imaging, and the precise action of germ cells that leads to the emergence of testicular morphology remains uncharacterized. Here, we report an agent-based model that simulates the mouse spermatogenic cycle on a cross-section of the seminiferous tubule over a time scale of hours to years, while considering feedback regulation, mitotic and meiotic division, differentiation, apoptosis, and movement. The computer model is able to elaborate the germ cell dynamics in a time-lapse movie format, allowing us to trace individual cells as they change state and location. More importantly, the model provides mechanistic understanding of the fundamentals of male fertility, namely how testicular morphology and sperm production are achieved. By manipulating cellular behaviors either individually or collectively in silico, the model predicts causal events for the altered arrangement of germ cells upon genetic or environmental perturbations. This in silico platform can serve as an interactive tool to perform long-term simulation and to identify optimal approaches for infertility treatment and contraceptive development.

  14. Computer simulation of heterogeneous polymer photovoltaic devices

    International Nuclear Information System (INIS)

    Kodali, Hari K; Ganapathysubramanian, Baskar

    2012-01-01

    Polymer-based photovoltaic devices have the potential for widespread usage due to their low cost per watt and mechanical flexibility. Efficiencies close to 9.0% have been achieved recently in conjugated polymer based organic solar cells (OSCs). These devices were fabricated using solvent-based processing of electron-donating and electron-accepting materials into the so-called bulk heterojunction (BHJ) architecture. Experimental evidence suggests that a key property determining the power-conversion efficiency of such devices is the final morphological distribution of the donor and acceptor constituents. In order to understand the role of morphology on device performance, we develop a scalable computational framework that efficiently interrogates OSCs to investigate relationships between the morphology at the nano-scale with the device performance. In this work, we extend the Buxton and Clarke model (2007 Modelling Simul. Mater. Sci. Eng. 15 13–26) to simulate realistic devices with complex active layer morphologies using a dimensionally independent, scalable, finite-element method. We incorporate all stages involved in current generation, namely (1) exciton generation and diffusion, (2) charge generation and (3) charge transport in a modular fashion. The numerical challenges encountered during interrogation of realistic microstructures are detailed. We compare each stage of the photovoltaic process for two microstructures: a BHJ morphology and an idealized sawtooth morphology. The results are presented for both two- and three-dimensional structures. (paper)

  15. Computer simulation of heterogeneous polymer photovoltaic devices

    Science.gov (United States)

    Kodali, Hari K.; Ganapathysubramanian, Baskar

    2012-04-01

    Polymer-based photovoltaic devices have the potential for widespread usage due to their low cost per watt and mechanical flexibility. Efficiencies close to 9.0% have been achieved recently in conjugated polymer based organic solar cells (OSCs). These devices were fabricated using solvent-based processing of electron-donating and electron-accepting materials into the so-called bulk heterojunction (BHJ) architecture. Experimental evidence suggests that a key property determining the power-conversion efficiency of such devices is the final morphological distribution of the donor and acceptor constituents. In order to understand the role of morphology on device performance, we develop a scalable computational framework that efficiently interrogates OSCs to investigate relationships between the morphology at the nano-scale with the device performance. In this work, we extend the Buxton and Clarke model (2007 Modelling Simul. Mater. Sci. Eng. 15 13-26) to simulate realistic devices with complex active layer morphologies using a dimensionally independent, scalable, finite-element method. We incorporate all stages involved in current generation, namely (1) exciton generation and diffusion, (2) charge generation and (3) charge transport in a modular fashion. The numerical challenges encountered during interrogation of realistic microstructures are detailed. We compare each stage of the photovoltaic process for two microstructures: a BHJ morphology and an idealized sawtooth morphology. The results are presented for both two- and three-dimensional structures.

  16. Sonification of simulations in computational physics

    International Nuclear Information System (INIS)

    Vogt, K.

    2010-01-01

    Sonification is the translation of information for auditory perception, excluding speech itself. The cognitive performance of pattern recognition is striking for sound, and has too long been disregarded by the scientific mainstream. Examples of 'spontaneous sonification' and systematic research for about 20 years have proven that sonification provides a valuable tool for the exploration of scientific data. The data in this thesis stem from computational physics, where numerical simulations are applied to problems in physics. Prominent examples are spin models and lattice quantum field theories. The corresponding data lend themselves very well to innovative display methods: they are structured on discrete lattices, often stochastic, high-dimensional and abstract, and they provide huge amounts of data. Furthermore, they have no inher- ently perceptual dimension. When designing the sonification of simulation data, one has to make decisions on three levels, both for the data and the sound model: the level of meaning (phenomenological; metaphoric); of structure (in time and space), and of elements ('display units' vs. 'gestalt units'). The design usually proceeds as a bottom-up or top-down process. This thesis provides a 'toolbox' for helping in these decisions. It describes tools that have proven particularly useful in the context of simulation data. An explicit method of top-down sonification design is the metaphoric sonification method, which is based on expert interviews. Furthermore, qualitative and quantitative evaluation methods are presented, on the basis of which a set of evaluation criteria is proposed. The translation between a scientific and the sound synthesis domain is elucidated by a sonification operator. For this formalization, a collection of notation modules is provided. Showcases are discussed in detail that have been developed in the interdisciplinary research projects SonEnvir and QCD-audio, during the second Science By Ear workshop and during a

  17. Engineering Fracking Fluids with Computer Simulation

    Science.gov (United States)

    Shaqfeh, Eric

    2015-11-01

    There are no comprehensive simulation-based tools for engineering the flows of viscoelastic fluid-particle suspensions in fully three-dimensional geometries. On the other hand, the need for such a tool in engineering applications is immense. Suspensions of rigid particles in viscoelastic fluids play key roles in many energy applications. For example, in oil drilling the ``drilling mud'' is a very viscous, viscoelastic fluid designed to shear-thin during drilling, but thicken at stoppage so that the ``cuttings'' can remain suspended. In a related application known as hydraulic fracturing suspensions of solids called ``proppant'' are used to prop open the fracture by pumping them into the well. It is well-known that particle flow and settling in a viscoelastic fluid can be quite different from that which is observed in Newtonian fluids. First, it is now well known that the ``fluid particle split'' at bifurcation cracks is controlled by fluid rheology in a manner that is not understood. Second, in Newtonian fluids, the presence of an imposed shear flow in the direction perpendicular to gravity (which we term a cross or orthogonal shear flow) has no effect on the settling of a spherical particle in Stokes flow (i.e. at vanishingly small Reynolds number). By contrast, in a non-Newtonian liquid, the complex rheological properties induce a nonlinear coupling between the sedimentation and shear flow. Recent experimental data have shown both the shear thinning and the elasticity of the suspending polymeric solutions significantly affects the fluid-particle split at bifurcations, as well as the settling rate of the solids. In the present work, we use the Immersed Boundary Method to develop computer simulations of viscoelastic flow in suspensions of spheres to study these problems. These simulations allow us to understand the detailed physical mechanisms for the remarkable physical behavior seen in practice, and actually suggest design rules for creating new fluid recipes.

  18. Development of the McGill simulator for endoscopic sinus surgery: a new high-fidelity virtual reality simulator for endoscopic sinus surgery.

    Science.gov (United States)

    Varshney, Rickul; Frenkiel, Saul; Nguyen, Lily H P; Young, Meredith; Del Maestro, Rolando; Zeitouni, Anthony; Tewfik, Marc A

    2014-01-01

    The technical challenges of endoscopic sinus surgery (ESS) and the high risk of complications support the development of alternative modalities to train residents in these procedures. Virtual reality simulation is becoming a useful tool for training the skills necessary for minimally invasive surgery; however, there are currently no ESS virtual reality simulators available with valid evidence supporting their use in resident education. Our aim was to develop a new rhinology simulator, as well as to define potential performance metrics for trainee assessment. The McGill simulator for endoscopic sinus surgery (MSESS), a new sinus surgery virtual reality simulator with haptic feedback, was developed (a collaboration between the McGill University Department of Otolaryngology-Head and Neck Surgery, the Montreal Neurologic Institute Simulation Lab, and the National Research Council of Canada). A panel of experts in education, performance assessment, rhinology, and skull base surgery convened to identify core technical abilities that would need to be taught by the simulator, as well as performance metrics to be developed and captured. The MSESS allows the user to perform basic sinus surgery skills, such as an ethmoidectomy and sphenoidotomy, through the use of endoscopic tools in a virtual nasal model. The performance metrics were developed by an expert panel and include measurements of safety, quality, and efficiency of the procedure. The MSESS incorporates novel technological advancements to create a realistic platform for trainees. To our knowledge, this is the first simulator to combine novel tools such as the endonasal wash and elaborate anatomic deformity with advanced performance metrics for ESS.

  19. Proceedings of the meeting on large scale computer simulation research

    International Nuclear Information System (INIS)

    2004-04-01

    The meeting to summarize the collaboration activities for FY2003 on the Large Scale Computer Simulation Research was held January 15-16, 2004 at Theory and Computer Simulation Research Center, National Institute for Fusion Science. Recent simulation results, methodologies and other related topics were presented. (author)

  20. Mixed reality simulation of rasping procedure in artificial cervical disc replacement (ACDR) surgery.

    Science.gov (United States)

    Halic, Tansel; Kockara, Sinan; Bayrak, Coskun; Rowe, Richard

    2010-10-07

    Until quite recently spinal disorder problems in the U.S. have been operated by fusing cervical vertebrae instead of replacement of the cervical disc with an artificial disc. Cervical disc replacement is a recently approved procedure in the U.S. It is one of the most challenging surgical procedures in the medical field due to the deficiencies in available diagnostic tools and insufficient number of surgical practices For physicians and surgical instrument developers, it is critical to understand how to successfully deploy the new artificial disc replacement systems. Without proper understanding and practice of the deployment procedure, it is possible to injure the vertebral body. Mixed reality (MR) and virtual reality (VR) surgical simulators are becoming an indispensable part of physicians' training, since they offer a risk free training environment. In this study, MR simulation framework and intricacies involved in the development of a MR simulator for the rasping procedure in artificial cervical disc replacement (ACDR) surgery are investigated. The major components that make up the MR surgical simulator with motion tracking system are addressed. A mixed reality surgical simulator that targets rasping procedure in the artificial cervical disc replacement surgery with a VICON motion tracking system was developed. There were several challenges in the development of MR surgical simulator. First, the assembly of different hardware components for surgical simulation development that involves knowledge and application of interdisciplinary fields such as signal processing, computer vision and graphics, along with the design and placements of sensors etc . Second challenge was the creation of a physically correct model of the rasping procedure in order to attain critical forces. This challenge was handled with finite element modeling. The third challenge was minimization of error in mapping movements of an actor in real model to a virtual model in a process called

  1. The role of computer simulation in nuclear technologies development

    International Nuclear Information System (INIS)

    Tikhonchev, M.Yu.; Shimansky, G.A.; Lebedeva, E.E.; Lichadeev, V. V.; Ryazanov, D.K.; Tellin, A.I.

    2001-01-01

    In the report the role and purposes of computer simulation in nuclear technologies development is discussed. The authors consider such applications of computer simulation as nuclear safety researches, optimization of technical and economic parameters of acting nuclear plant, planning and support of reactor experiments, research and design new devices and technologies, design and development of 'simulators' for operating personnel training. Among marked applications the following aspects of computer simulation are discussed in the report: neutron-physical, thermal and hydrodynamics models, simulation of isotope structure change and damage dose accumulation for materials under irradiation, simulation of reactor control structures. (authors)

  2. The role of computer simulation in nuclear technology development

    International Nuclear Information System (INIS)

    Tikhonchev, M.Yu.; Shimansky, G.A.; Lebedeva, E.E.; Lichadeev, VV.; Ryazanov, D.K.; Tellin, A.I.

    2000-01-01

    In the report, the role and purpose of computer simulation in nuclear technology development is discussed. The authors consider such applications of computer simulation as: (a) Nuclear safety research; (b) Optimization of technical and economic parameters of acting nuclear plant; (c) Planning and support of reactor experiments; (d) Research and design new devices and technologies; (f) Design and development of 'simulators' for operating personnel training. Among marked applications, the following aspects of computer simulation are discussed in the report: (g) Neutron-physical, thermal and hydrodynamics models; (h) Simulation of isotope structure change and dam- age dose accumulation for materials under irradiation; (i) Simulation of reactor control structures. (authors)

  3. MRI in 'failed back surgery syndrome': Comparison to computed tomography

    International Nuclear Information System (INIS)

    Trattnig, S.; Ungersboeck, K.; Cech, T.; Schindler, E.

    1990-01-01

    The term 'failed back surgery syndrome' (FBSS) includes a variety of clinical-neurological symptoms following disc surgery. In a prospective study 18 patients suffering from monoradicular symptoms after disc surgery were examined by MRI and CT (both prior to and following intravenous application of contrast material). Findings were then compared to microsurgery. MRI produced correct diagnoses in 17 cases, CT in 13 cases. Recurrent disc herniation caused symptoms four times, and epidural scar formation twice. In twelve cases there was herniated disc material as well as an epidural scar present; disc material preponderated nine times, scar formation in three instances. (orig.) [de

  4. [Simulation of lung lobe resection with personal computer].

    Science.gov (United States)

    Onuki, T; Murasugi, M; Mae, M; Koyama, K; Ikeda, T; Shimizu, T

    2005-09-01

    Various patterns of branching are seen for pulmonary arteries and veins in the lung hilum. However, thoracic surgeons usually cannot expect to discern much anatomical detail preoperatively. If the surgeon can gain an understanding of individual patterns preoperatively, the risks inherent in exposing the pulmonary vessels in the hilum can be avoided, reducing invasiveness. This software will meet the increasing needs of them in video-assisted thoracoscopic surgery (VATS) which prefer lesser dissections of the vessels and bronchus of hilum. We have produced free application software, where we can mark on pulmonary arteries, vein, bronchus and tumor of the successive images of computed tomography (CT). After receiving a compact disk containing 60 images of 2 mm CT slices, from tumor to hilum, in DICOM format, we required only 1 hour to obtain 3-dimensional images for a patient with other free software (Metasequoia LE). Furthermore, with Metasequoia LE, we can simulate cut the vessels and change the figure of them 3-dimensionally. Although the picture image leaves much room for improvement, we believe it is very attractive for residents because they can simulate operations.

  5. Simulation of a small computer of the TRA-1001 type on the BESM computer

    International Nuclear Information System (INIS)

    Galaktionov, V.V.

    1975-01-01

    Considered are the purpose and probable simulation ways of one computer by the other. The emulator (simulation program) is given for a small computer of TRA-1001 type on BESM-6 computer. The simulated computer basic elements are the following: memory (8 K words), central processor, input-output program channel, interruption circuit, computer panel. The work with the input-output devices, teletypes ASP-33, FS-1500 is also simulated. Under actual operation the emulator has been used for translating the programs prepared on punched cards with the aid of translator SLANG-1 by BESM-6 computer. The translator alignment from language COPLAN has been realized with the aid of the emulator

  6. High-fidelity haptic and visual rendering for patient-specific simulation of temporal bone surgery.

    Science.gov (United States)

    Chan, Sonny; Li, Peter; Locketz, Garrett; Salisbury, Kenneth; Blevins, Nikolas H

    2016-12-01

    Medical imaging techniques provide a wealth of information for surgical preparation, but it is still often the case that surgeons are examining three-dimensional pre-operative image data as a series of two-dimensional images. With recent advances in visual computing and interactive technologies, there is much opportunity to provide surgeons an ability to actively manipulate and interpret digital image data in a surgically meaningful way. This article describes the design and initial evaluation of a virtual surgical environment that supports patient-specific simulation of temporal bone surgery using pre-operative medical image data. Computational methods are presented that enable six degree-of-freedom haptic feedback during manipulation, and that simulate virtual dissection according to the mechanical principles of orthogonal cutting and abrasive wear. A highly efficient direct volume renderer simultaneously provides high-fidelity visual feedback during surgical manipulation of the virtual anatomy. The resulting virtual surgical environment was assessed by evaluating its ability to replicate findings in the operating room, using pre-operative imaging of the same patient. Correspondences between surgical exposure, anatomical features, and the locations of pathology were readily observed when comparing intra-operative video with the simulation, indicating the predictive ability of the virtual surgical environment.

  7. Prototyping and Simulating Parallel, Distributed Computations with VISA

    National Research Council Canada - National Science Library

    Demeure, Isabelle M; Nutt, Gary J

    1989-01-01

    ...] to support the design, prototyping, and simulation of parallel, distributed computations. In particular, VISA is meant to guide the choice of partitioning and communication strategies for such computations, based on their performance...

  8. Supporting hypothesis generation by learners exploring an interactive computer simulation

    NARCIS (Netherlands)

    van Joolingen, Wouter R.; de Jong, Ton

    1992-01-01

    Computer simulations provide environments enabling exploratory learning. Research has shown that these types of learning environments are promising applications of computer assisted learning but also that they introduce complex learning settings, involving a large number of learning processes. This

  9. Optical Head-Mounted Computer Display for Education, Research, and Documentation in Hand Surgery.

    Science.gov (United States)

    Funk, Shawn; Lee, Donald H

    2016-01-01

    Intraoperative photography and capturing videos is important for the hand surgeon. Recently, optical head-mounted computer display has been introduced as a means of capturing photographs and videos. In this article, we discuss this new technology and review its potential use in hand surgery. Copyright © 2016 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

  10. Computer control versus manual control of systemic hypertension during cardiac surgery

    NARCIS (Netherlands)

    Hoeksel, S.A.A.P.; Blom, J.A.; Jansen, J.R.C.; Maessen, J.G.; Schreuder, J.J.

    2001-01-01

    Keywords:Cardiac surgery;hypertension;closed-loop controlBackground: We recently demonstrated the feasibility of computer controlled infusion of vasoactive drugs for the control of systemic hypertension during cardiac surgery. The objective of the current study was to investigate the effects of

  11. Radiologic anatomy of the paranasal sinuses in computed tomography for the need of the endoscopic surgery

    International Nuclear Information System (INIS)

    Boguslawska-Staniaszczyk, R.; Krzeski, A.; Mastalerski, J.

    1994-01-01

    Computed tomography is the most useful method in the endoscopic surgery of the nose and paranasal sinuses. CT examination is necessary for planing and the extent of the surgery. In this publication the method of CT examination and radiological anatomy of the nose and paranasal sinuses is described. (author)

  12. 76 FR 75887 - SEDASYS Computer-Assisted Personalized Sedation System; Ethicon Endo-Surgery, Incorporated's...

    Science.gov (United States)

    2011-12-05

    ... DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and Drug Administration [Docket No. FDA-2010-P-0176] SEDASYS Computer-Assisted Personalized Sedation System; Ethicon Endo-Surgery, Incorporated's Petition for... system (SEDASYS) submitted by Ethicon Endo-Surgery Inc. (EES), the sponsor for SEDASYS. This meeting has...

  13. Growing skin: A computational model for skin expansion in reconstructive surgery

    Science.gov (United States)

    Buganza Tepole, Adrián; Joseph Ploch, Christopher; Wong, Jonathan; Gosain, Arun K.; Kuhl, Ellen

    2011-10-01

    The goal of this manuscript is to establish a novel computational model for stretch-induced skin growth during tissue expansion. Tissue expansion is a common surgical procedure to grow extra skin for reconstructing birth defects, burn injuries, or cancerous breasts. To model skin growth within the framework of nonlinear continuum mechanics, we adopt the multiplicative decomposition of the deformation gradient into an elastic and a growth part. Within this concept, we characterize growth as an irreversible, stretch-driven, transversely isotropic process parameterized in terms of a single scalar-valued growth multiplier, the in-plane area growth. To discretize its evolution in time, we apply an unconditionally stable, implicit Euler backward scheme. To discretize it in space, we utilize the finite element method. For maximum algorithmic efficiency and optimal convergence, we suggest an inner Newton iteration to locally update the growth multiplier at each integration point. This iteration is embedded within an outer Newton iteration to globally update the deformation at each finite element node. To demonstrate the characteristic features of skin growth, we simulate the process of gradual tissue expander inflation. To visualize growth-induced residual stresses, we simulate a subsequent tissue expander deflation. In particular, we compare the spatio-temporal evolution of area growth, elastic strains, and residual stresses for four commonly available tissue expander geometries. We believe that predictive computational modeling can open new avenues in reconstructive surgery to rationalize and standardize clinical process parameters such as expander geometry, expander size, expander placement, and inflation timing.

  14. COMPUTER LEARNING SIMULATOR WITH VIRTUAL REALITY FOR OPHTHALMOLOGY

    Directory of Open Access Journals (Sweden)

    Valeria V. Gribova

    2013-01-01

    Full Text Available A toolset of a medical computer learning simulator for ophthalmology with virtual reality and its implementation are considered in the paper. The simulator is oriented for professional skills training for students of medical universities. 

  15. QDENSITY—A Mathematica quantum computer simulation

    Science.gov (United States)

    Juliá-Díaz, Bruno; Burdis, Joseph M.; Tabakin, Frank

    2009-03-01

    This Mathematica 6.0 package is a simulation of a Quantum Computer. The program provides a modular, instructive approach for generating the basic elements that make up a quantum circuit. The main emphasis is on using the density matrix, although an approach using state vectors is also implemented in the package. The package commands are defined in Qdensity.m which contains the tools needed in quantum circuits, e.g., multiqubit kets, projectors, gates, etc. New version program summaryProgram title: QDENSITY 2.0 Catalogue identifier: ADXH_v2_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADXH_v2_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 26 055 No. of bytes in distributed program, including test data, etc.: 227 540 Distribution format: tar.gz Programming language: Mathematica 6.0 Operating system: Any which supports Mathematica; tested under Microsoft Windows XP, Macintosh OS X, and Linux FC4 Catalogue identifier of previous version: ADXH_v1_0 Journal reference of previous version: Comput. Phys. Comm. 174 (2006) 914 Classification: 4.15 Does the new version supersede the previous version?: Offers an alternative, more up to date, implementation Nature of problem: Analysis and design of quantum circuits, quantum algorithms and quantum clusters. Solution method: A Mathematica package is provided which contains commands to create and analyze quantum circuits. Several Mathematica notebooks containing relevant examples: Teleportation, Shor's Algorithm and Grover's search are explained in detail. A tutorial, Tutorial.nb is also enclosed. Reasons for new version: The package has been updated to make it fully compatible with Mathematica 6.0 Summary of revisions: The package has been updated to make it fully compatible with Mathematica 6.0 Running time: Most examples

  16. Efficacy of navigation in skull base surgery using composite computer graphics of magnetic resonance and computed tomography images

    International Nuclear Information System (INIS)

    Hayashi, Nakamasa; Kurimoto, Masanori; Hirashima, Yutaka; Ikeda, Hiroaki; Shibata, Takashi; Tomita, Takahiro; Endo, Shunro

    2001-01-01

    The efficacy of a neurosurgical navigation system using three-dimensional composite computer graphics (CGs) of magnetic resonance (MR) and computed tomography (CT) images was evaluated in skull base surgery. Three-point transformation was used for integration of MR and CT images. MR and CT image data were obtained with three skin markers placed on the patient's scalp. Volume-rendering manipulations of the data produced three-dimensional CGs of the scalp, brain, and lesions from the MR images, and the scalp and skull from the CT. Composite CGs of the scalp, skull, brain, and lesion were created by registering the three markers on the three-dimensional rendered scalp images obtained from MR imaging and CT in the system. This system was used for 14 patients with skull base lesions. Three-point transformation using three-dimensional CGs was easily performed for multimodal registration. Simulation of surgical procedures on composite CGs aided in comprehension of the skull base anatomy and selection of the optimal approaches. Intraoperative navigation aided in determination of actual spatial position in the skull base and the optimal trajectory to the tumor during surgical procedures. (author)

  17. Computer simulation boosts automation in the stockyard

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-04-01

    Today's desktop computer and advanced software keep pace with handling equipment to reach new heights of sophistication with graphic simulation able to show precisely what is and could happen in the coal terminal's stockyard. The article describes an innovative coal terminal nearing completion on the Pacific coast at Lazaro Cardenas in Mexico, called the Petracalco terminal. Here coal is unloaded, stored and fed to the nearby power plant of Pdte Plutarco Elias Calles. The R & D department of the Italian company Techint, Italimpianti has developed MHATIS, a sophisticated software system for marine terminal management here, allowing analysis of performance with the use of graphical animation. Strategies can be tested before being put into practice and likely power station demand can be predicted. The design and operation of the MHATIS system is explained. Other integrated coal handling plants described in the article are that developed by the then PWH (renamed Krupp Foerdertechnik) of Germany for the Israel Electric Corporation and the installation by the same company of a further bucketwheel for a redesigned coal stockyard at the Port of Hamburg operated by Hansaport. 1 fig., 4 photos.

  18. Identification of New Tools to Predict Surgical Performance of Novices using a Plastic Surgery Simulator.

    Science.gov (United States)

    Kazan, Roy; Viezel-Mathieu, Alex; Cyr, Shantale; Hemmerling, Thomas M; Lin, Samuel J; Gilardino, Mirko S

    2018-04-09

    To identify new tools capable of predicting surgical performance of novices on an augmentation mammoplasty simulator. The pace of technical skills acquisition varies between residents and may necessitate more time than that allotted by residency training before reaching competence. Identifying applicants with superior innate technical abilities might shorten learning curves and the time to reach competence. The objective of this study is to identify new tools that could predict surgical performance of novices on a mammoplasty simulator. We recruited 14 medical students and recorded their performance in 2 skill-games: Mikado and Perplexus Epic, and in 2 video games: Star War Racer (Sony Playstation 3) and Super Monkey Ball 2 (Nintendo Wii). Then, each participant performed an augmentation mammoplasty procedure on a Mammoplasty Part-task Trainer, which allows the simulation of the essential steps of the procedure. The average age of participants was 25.4 years. Correlation studies showed significant association between Perplexus Epic, Star Wars Racer, Super Monkey Ball scores and the modified OSATS score with r s = 0.8491 (p 41 (p = 0.005), and r s = 0.7309 (p < 0.003), but not with the Mikado score r s = -0.0255 (p = 0.9). Linear regressions were strongest for Perplexus Epic and Super Monkey Ball scores with coefficients of determination of 0.59 and 0.55, respectively. A combined score (Perplexus/Super-Monkey-Ball) was computed and showed a significant correlation with the modified OSATS score having an r s = 0.8107 (p < 0.001) and R 2 = 0.75, respectively. This study identified a combination of skill games that correlated to better performance of novices on a surgical simulator. With refinement, such tools could serve to help screen plastic surgery applicants and identify those with higher surgical performance predictors. Copyright © 2018 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.

  19. Teaching Computer Organization and Architecture Using Simulation and FPGA Applications

    OpenAIRE

    D. K.M. Al-Aubidy

    2007-01-01

    This paper presents the design concepts and realization of incorporating micro-operation simulation and FPGA implementation into a teaching tool for computer organization and architecture. This teaching tool helps computer engineering and computer science students to be familiarized practically with computer organization and architecture through the development of their own instruction set, computer programming and interfacing experiments. A two-pass assembler has been designed and implemente...

  20. Overview of Computer Simulation Modeling Approaches and Methods

    Science.gov (United States)

    Robert E. Manning; Robert M. Itami; David N. Cole; Randy Gimblett

    2005-01-01

    The field of simulation modeling has grown greatly with recent advances in computer hardware and software. Much of this work has involved large scientific and industrial applications for which substantial financial resources are available. However, advances in object-oriented programming and simulation methodology, concurrent with dramatic increases in computer...

  1. The Use of Computer Simulation Gaming in Teaching Broadcast Economics.

    Science.gov (United States)

    Mancuso, Louis C.

    The purpose of this study was to develop a broadcast economic computer simulation and to ascertain how a lecture-computer simulation game compared as a teaching method with a more traditional lecture and case study instructional methods. In each of three sections of a broadcast economics course, a different teaching methodology was employed: (1)…

  2. The visual simulators for architecture and computer organization learning

    OpenAIRE

    Nikolić Boško; Grbanović Nenad; Đorđević Jovan

    2009-01-01

    The paper proposes a method of an effective distance learning of architecture and computer organization. The proposed method is based on a software system that is possible to be applied in any course in this field. Within this system students are enabled to observe simulation of already created computer systems. The system provides creation and simulation of switch systems, too.

  3. Computer Simulation (Microcultures): An Effective Model for Multicultural Education.

    Science.gov (United States)

    Nelson, Jorge O.

    This paper presents a rationale for using high-fidelity computer simulation in planning for and implementing effective multicultural education strategies. Using computer simulation, educators can begin to understand and plan for the concept of cultural sensitivity in delivering instruction. The model promises to emphasize teachers' understanding…

  4. New Pedagogies on Teaching Science with Computer Simulations

    Science.gov (United States)

    Khan, Samia

    2011-01-01

    Teaching science with computer simulations is a complex undertaking. This case study examines how an experienced science teacher taught chemistry using computer simulations and the impact of his teaching on his students. Classroom observations over 3 semesters, teacher interviews, and student surveys were collected. The data was analyzed for (1)…

  5. Evaluation of Computer Simulations for Teaching Apparel Merchandising Concepts.

    Science.gov (United States)

    Jolly, Laura D.; Sisler, Grovalynn

    1988-01-01

    The study developed and evaluated computer simulations for teaching apparel merchandising concepts. Evaluation results indicated that teaching method (computer simulation versus case study) does not significantly affect cognitive learning. Student attitudes varied, however, according to topic (profitable merchandising analysis versus retailing…

  6. Simulation in computer forensics teaching: the student experience

    OpenAIRE

    Crellin, Jonathan; Adda, Mo; Duke-Williams, Emma; Chandler, Jane

    2011-01-01

    The use of simulation in teaching computing is well established, with digital forensic investigation being a subject area where the range of simulation required is both wide and varied demanding a corresponding breadth of fidelity. Each type of simulation can be complex and expensive to set up resulting in students having only limited opportunities to participate and learn from the simulation. For example students' participation in mock trials in the University mock courtroom or in simulation...

  7. Challenges & Roadmap for Beyond CMOS Computing Simulation.

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, Arun F. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Frank, Michael P. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-12-01

    Simulating HPC systems is a difficult task and the emergence of “Beyond CMOS” architectures and execution models will increase that difficulty. This document presents a “tutorial” on some of the simulation challenges faced by conventional and non-conventional architectures (Section 1) and goals and requirements for simulating Beyond CMOS systems (Section 2). These provide background for proposed short- and long-term roadmaps for simulation efforts at Sandia (Sections 3 and 4). Additionally, a brief explanation of a proof-of-concept integration of a Beyond CMOS architectural simulator is presented (Section 2.3).

  8. Student perception of two different simulation techniques in oral and maxillofacial surgery undergraduate training.

    Science.gov (United States)

    Lund, Bodil; Fors, Uno; Sejersen, Ronny; Sallnäs, Eva-Lotta; Rosén, Annika

    2011-10-12

    Yearly surveys among the undergraduate students in oral and maxillofacial surgery at Karolinska Institutet have conveyed a wish for increased clinical training, and in particular, in surgical removal of mandibular third molars. Due to lack of resources, this kind of clinical supervision has so far not been possible to implement. One possible solution to this problem might be to introduce simulation into the curriculum. The purpose of this study was to investigate undergraduate students' perception of two different simulation methods for practicing clinical reasoning skills and technical skills in oral and maxillofacial surgery. Forty-seven students participating in the oral and maxillofacial surgery course at Karolinska Institutet during their final year were included. Three different oral surgery patient cases were created in a Virtual Patient (VP) Simulation system (Web-SP) and used for training clinical reasoning. A mandibular third molar surgery simulator with tactile feedback, providing hands on training in the bone removal and tooth sectioning in third molar surgery, was also tested. A seminar was performed using the combination of these two simulators where students' perception of the two different simulation methods was assessed by means of a questionnaire. The response rate was 91.5% (43/47). The students were positive to the VP cases, although they rated their possible improvement of clinical reasoning skills as moderate. The students' perception of improved technical skills after training in the mandibular third molar surgery simulator was rated high. The majority of the students agreed that both simulation techniques should be included in the curriculum and strongly agreed that it was a good idea to use the two simulators in concert. The importance of feedback from the senior experts during simulator training was emphasised. The two tested simulation methods were well accepted and most students agreed that the future curriculum would benefit from

  9. GPU-accelerated micromagnetic simulations using cloud computing

    International Nuclear Information System (INIS)

    Jermain, C.L.; Rowlands, G.E.; Buhrman, R.A.; Ralph, D.C.

    2016-01-01

    Highly parallel graphics processing units (GPUs) can improve the speed of micromagnetic simulations significantly as compared to conventional computing using central processing units (CPUs). We present a strategy for performing GPU-accelerated micromagnetic simulations by utilizing cost-effective GPU access offered by cloud computing services with an open-source Python-based program for running the MuMax3 micromagnetics code remotely. We analyze the scaling and cost benefits of using cloud computing for micromagnetics. - Highlights: • The benefits of cloud computing for GPU-accelerated micromagnetics are examined. • We present the MuCloud software for running simulations on cloud computing. • Simulation run times are measured to benchmark cloud computing performance. • Comparison benchmarks are analyzed between CPU and GPU based solvers.

  10. GPU-accelerated micromagnetic simulations using cloud computing

    Energy Technology Data Exchange (ETDEWEB)

    Jermain, C.L., E-mail: clj72@cornell.edu [Cornell University, Ithaca, NY 14853 (United States); Rowlands, G.E.; Buhrman, R.A. [Cornell University, Ithaca, NY 14853 (United States); Ralph, D.C. [Cornell University, Ithaca, NY 14853 (United States); Kavli Institute at Cornell, Ithaca, NY 14853 (United States)

    2016-03-01

    Highly parallel graphics processing units (GPUs) can improve the speed of micromagnetic simulations significantly as compared to conventional computing using central processing units (CPUs). We present a strategy for performing GPU-accelerated micromagnetic simulations by utilizing cost-effective GPU access offered by cloud computing services with an open-source Python-based program for running the MuMax3 micromagnetics code remotely. We analyze the scaling and cost benefits of using cloud computing for micromagnetics. - Highlights: • The benefits of cloud computing for GPU-accelerated micromagnetics are examined. • We present the MuCloud software for running simulations on cloud computing. • Simulation run times are measured to benchmark cloud computing performance. • Comparison benchmarks are analyzed between CPU and GPU based solvers.

  11. General-purpose parallel simulator for quantum computing

    International Nuclear Information System (INIS)

    Niwa, Jumpei; Matsumoto, Keiji; Imai, Hiroshi

    2002-01-01

    With current technologies, it seems to be very difficult to implement quantum computers with many qubits. It is therefore of importance to simulate quantum algorithms and circuits on the existing computers. However, for a large-size problem, the simulation often requires more computational power than is available from sequential processing. Therefore, simulation methods for parallel processors are required. We have developed a general-purpose simulator for quantum algorithms/circuits on the parallel computer (Sun Enterprise4500). It can simulate algorithms/circuits with up to 30 qubits. In order to test efficiency of our proposed methods, we have simulated Shor's factorization algorithm and Grover's database search, and we have analyzed robustness of the corresponding quantum circuits in the presence of both decoherence and operational errors. The corresponding results, statistics, and analyses are presented in this paper

  12. Performance Analysis of Cloud Computing Architectures Using Discrete Event Simulation

    Science.gov (United States)

    Stocker, John C.; Golomb, Andrew M.

    2011-01-01

    Cloud computing offers the economic benefit of on-demand resource allocation to meet changing enterprise computing needs. However, the flexibility of cloud computing is disadvantaged when compared to traditional hosting in providing predictable application and service performance. Cloud computing relies on resource scheduling in a virtualized network-centric server environment, which makes static performance analysis infeasible. We developed a discrete event simulation model to evaluate the overall effectiveness of organizations in executing their workflow in traditional and cloud computing architectures. The two part model framework characterizes both the demand using a probability distribution for each type of service request as well as enterprise computing resource constraints. Our simulations provide quantitative analysis to design and provision computing architectures that maximize overall mission effectiveness. We share our analysis of key resource constraints in cloud computing architectures and findings on the appropriateness of cloud computing in various applications.

  13. Alternative energy technologies an introduction with computer simulations

    CERN Document Server

    Buxton, Gavin

    2014-01-01

    Introduction to Alternative Energy SourcesGlobal WarmingPollutionSolar CellsWind PowerBiofuelsHydrogen Production and Fuel CellsIntroduction to Computer ModelingBrief History of Computer SimulationsMotivation and Applications of Computer ModelsUsing Spreadsheets for SimulationsTyping Equations into SpreadsheetsFunctions Available in SpreadsheetsRandom NumbersPlotting DataMacros and ScriptsInterpolation and ExtrapolationNumerical Integration and Diffe

  14. Integrated computer aided design simulation and manufacture

    OpenAIRE

    Diko, Faek

    1989-01-01

    Computer Aided Design (CAD) and Computer Aided Manufacture (CAM) have been investigated and developed since twenty years as standalone systems. A large number of very powerful but independent packages have been developed for Computer Aided Design,Aanlysis and Manufacture. However, in most cases these packages have poor facility for communicating with other packages. Recently attempts have been made to develop integrated CAD/CAM systems and many software companies a...

  15. Building an adiabatic quantum computer simulation in the classroom

    Science.gov (United States)

    Rodríguez-Laguna, Javier; Santalla, Silvia N.

    2018-05-01

    We present a didactic introduction to adiabatic quantum computation (AQC) via the explicit construction of a classical simulator of quantum computers. This constitutes a suitable route to introduce several important concepts for advanced undergraduates in physics: quantum many-body systems, quantum phase transitions, disordered systems, spin-glasses, and computational complexity theory.

  16. Legal issues of computer imaging in plastic surgery: a primer.

    Science.gov (United States)

    Chávez, A E; Dagum, P; Koch, R J; Newman, J P

    1997-11-01

    Although plastic surgeons are increasingly incorporating computer imaging techniques into their practices, many fear the possibility of legally binding themselves to achieve surgical results identical to those reflected in computer images. Computer imaging allows surgeons to manipulate digital photographs of patients to project possible surgical outcomes. Some of the many benefits imaging techniques pose include improving doctor-patient communication, facilitating the education and training of residents, and reducing administrative and storage costs. Despite the many advantages computer imaging systems offer, however, surgeons understandably worry that imaging systems expose them to immense legal liability. The possible exploitation of computer imaging by novice surgeons as a marketing tool, coupled with the lack of consensus regarding the treatment of computer images, adds to the concern of surgeons. A careful analysis of the law, however, reveals that surgeons who use computer imaging carefully and conservatively, and adopt a few simple precautions, substantially reduce their vulnerability to legal claims. In particular, surgeons face possible claims of implied contract, failure to instruct, and malpractice from their use or failure to use computer imaging. Nevertheless, legal and practical obstacles frustrate each of those causes of actions. Moreover, surgeons who incorporate a few simple safeguards into their practice may further reduce their legal susceptibility.

  17. Quantum computer gate simulations | Dada | Journal of the Nigerian ...

    African Journals Online (AJOL)

    A new interactive simulator for Quantum Computation has been developed for simulation of the universal set of quantum gates and for construction of new gates of up to 3 qubits. The simulator also automatically generates an equivalent quantum circuit for any arbitrary unitary transformation on a qubit. Available quantum ...

  18. Computer Simulation of the Circulation Subsystem of a Library

    Science.gov (United States)

    Shaw, W. M., Jr.

    1975-01-01

    When circulation data are used as input parameters for a computer simulation of a library's circulation subsystem, the results of the simulation provide information on book availability and delays. The model may be used to simulate alternative loan policies. (Author/LS)

  19. A note on simulated annealing to computer laboratory scheduling ...

    African Journals Online (AJOL)

    The concepts, principles and implementation of simulated Annealing as a modem heuristic technique is presented. Simulated Annealing algorithm is used in solving real life problem of Computer Laboratory scheduling in order to maximize the use of scarce and insufficient resources. KEY WORDS: Simulated Annealing ...

  20. The challenge of quantum computer simulations of physical phenomena

    International Nuclear Information System (INIS)

    Ortiz, G.; Knill, E.; Gubernatis, J.E.

    2002-01-01

    The goal of physics simulation using controllable quantum systems ('physics imitation') is to exploit quantum laws to advantage, and thus accomplish efficient simulation of physical phenomena. In this Note, we discuss the fundamental concepts behind this paradigm of information processing, such as the connection between models of computation and physical systems. The experimental simulation of a toy quantum many-body problem is described

  1. [Three-dimensional display simulation of lung surgery using "active shutter glasses"].

    Science.gov (United States)

    Onuki, Takamasa; Kanzaki, Masato; Sakamoto, Kei; Kikkawa, Takuma; Isaka, Tamami; Shimizu, Toshihide; Oyama, Kunihiro; Murasugi, Masahide

    2011-08-01

    We have reported preoperative 3-dimensional (3D) simulation of thoracoscopic lung surgery using self-made software and internet shareware of 3D-modeler. Using "active shutter glasses", we have tried the "3D display simulation" of lung surgery. 3D display was more effective to grasp clear 3D interrelation between the bronchii and pulmonary vascular system than those in images of currently in use with the same information volume.

  2. A Novel Haptic Interactive Approach to Simulation of Surgery Cutting Based on Mesh and Meshless Models

    Science.gov (United States)

    Liu, Peter X.; Lai, Pinhua; Xu, Shaoping; Zou, Yanni

    2018-01-01

    In the present work, the majority of implemented virtual surgery simulation systems have been based on either a mesh or meshless strategy with regard to soft tissue modelling. To take full advantage of the mesh and meshless models, a novel coupled soft tissue cutting model is proposed. Specifically, the reconstructed virtual soft tissue consists of two essential components. One is associated with surface mesh that is convenient for surface rendering and the other with internal meshless point elements that is used to calculate the force feedback during cutting. To combine two components in a seamless way, virtual points are introduced. During the simulation of cutting, the Bezier curve is used to characterize smooth and vivid incision on the surface mesh. At the same time, the deformation of internal soft tissue caused by cutting operation can be treated as displacements of the internal point elements. Furthermore, we discussed and proved the stability and convergence of the proposed approach theoretically. The real biomechanical tests verified the validity of the introduced model. And the simulation experiments show that the proposed approach offers high computational efficiency and good visual effect, enabling cutting of soft tissue with high stability. PMID:29850006

  3. CPU SIM: A Computer Simulator for Use in an Introductory Computer Organization-Architecture Class.

    Science.gov (United States)

    Skrein, Dale

    1994-01-01

    CPU SIM, an interactive low-level computer simulation package that runs on the Macintosh computer, is described. The program is designed for instructional use in the first or second year of undergraduate computer science, to teach various features of typical computer organization through hands-on exercises. (MSE)

  4. A review of simulation platforms in surgery of the temporal bone.

    Science.gov (United States)

    Bhutta, M F

    2016-10-01

    Surgery of the temporal bone is a high-risk activity in an anatomically complex area. Simulation enables rehearsal of such surgery. The traditional simulation platform is the cadaveric temporal bone, but in recent years other simulation platforms have been created, including plastic and virtual reality platforms. To undertake a review of simulation platforms for temporal bone surgery, specifically assessing their educational value in terms of validity and in enabling transition to surgery. Systematic qualitative review. Search of the Pubmed, CINAHL, BEI and ERIC databases. Assessment of reported outcomes in terms of educational value. A total of 49 articles were included, covering cadaveric, animal, plastic and virtual simulation platforms. Cadaveric simulation is highly rated as an educational tool, but there may be a ceiling effect on educational outcomes after drilling 8-10 temporal bones. Animal models show significant anatomical variation from man. Plastic temporal bone models offer much potential, but at present lack sufficient anatomical or haptic validity. Similarly, virtual reality platforms lack sufficient anatomical or haptic validity, but with technological improvements they are advancing rapidly. At present, cadaveric simulation remains the best platform for training in temporal bone surgery. Technological advances enabling improved materials or modelling mean that in the future plastic or virtual platforms may become comparable to cadaveric platforms, and also offer additional functionality including patient-specific simulation from CT data. © 2015 John Wiley & Sons Ltd.

  5. Computer simulation of grain growth in HAZ

    Science.gov (United States)

    Gao, Jinhua

    Two different models for Monte Carlo simulation of normal grain growth in metals and alloys were developed. Each simulation model was based on a different approach to couple the Monte Carlo simulation time to real time-temperature. These models demonstrated the applicability of Monte Carlo simulation to grain growth in materials processing. A grain boundary migration (GBM) model coupled the Monte Carlo simulation to a first principle grain boundary migration model. The simulation results, by applying this model to isothermal grain growth in zone-refined tin, showed good agreement with experimental results. An experimental data based (EDB) model coupled the Monte Carlo simulation with grain growth kinetics obtained from the experiment. The results of the application of the EDB model to the grain growth during continuous heating of a beta titanium alloy correlated well with experimental data. In order to acquire the grain growth kinetics from the experiment, a new mathematical method was developed and utilized to analyze the experimental data on isothermal grain growth. Grain growth in the HAZ of 0.2% Cu-Al alloy was successfully simulated using the EDB model combined with grain growth kinetics obtained from the experiment and measured thermal cycles from the welding process. The simulated grain size distribution in the HAZ was in good agreement with experimental results. The pinning effect of second phase particles on grain growth was also simulated in this work. The simulation results confirmed that by introducing the variable R, degree of contact between grain boundaries and second phase particles, the Zener pinning model can be modified as${D/ r} = {K/{Rf}}$where D is the pinned grain size, r the mean size of second phase particles, K a constant, f the area fraction (or the volume fraction in 3-D) of second phase.

  6. Fluid dynamics theory, computation, and numerical simulation

    CERN Document Server

    Pozrikidis, C

    2017-01-01

    This book provides an accessible introduction to the basic theory of fluid mechanics and computational fluid dynamics (CFD) from a modern perspective that unifies theory and numerical computation. Methods of scientific computing are introduced alongside with theoretical analysis and MATLAB® codes are presented and discussed for a broad range of topics: from interfacial shapes in hydrostatics, to vortex dynamics, to viscous flow, to turbulent flow, to panel methods for flow past airfoils. The third edition includes new topics, additional examples, solved and unsolved problems, and revised images. It adds more computational algorithms and MATLAB programs. It also incorporates discussion of the latest version of the fluid dynamics software library FDLIB, which is freely available online. FDLIB offers an extensive range of computer codes that demonstrate the implementation of elementary and advanced algorithms and provide an invaluable resource for research, teaching, classroom instruction, and self-study. This ...

  7. Computer-based laparoscopic and robotic surgical simulators: performance characteristics and perceptions of new users.

    Science.gov (United States)

    Lin, David W; Romanelli, John R; Kuhn, Jay N; Thompson, Renee E; Bush, Ron W; Seymour, Neal E

    2009-01-01

    This study aimed to define perceptions of the need and the value of new simulation devices for laparoscopic and robot-assisted surgery. The initial experience of surgeons using both robotic and nonrobotic laparoscopic simulators to perform an advanced laparoscopic skill was evaluated. At the 2006 Society of American Gastroesophageal Surgeons (SAGES) meeting, 63 Learning Center attendees used a new virtual reality robotic surgery simulator (SEP Robot) and either a computer-enhanced laparoscopic simulator (ProMIS) or a virtual reality simulator (SurgicalSIM). Demographic and training data were collected by an intake survey. Subjects then were assessed during one iteration of laparoscopic suturing and knot-tying on the SEP Robot and either the ProMIS or the SurgicalSIM. A posttask survey determined users' impressions of task realism, interface quality, and educational value. Performance data were collected and comparisons made between user-defined groups, different simulation platforms, and posttask survey responses. The task completion rate was significantly greater for experts than for nonexperts on the virtual reality platforms (SurgicalSIM: 100% vs 36%; SEP Robot: 93% vs 63%; p platforms, whereas simulator metrics best discriminated expertise for the videoscopic platform. Similar comparisons for the virtual reality platforms were not feasible because of the low task completion rate for nonexperts. The added degrees of freedom associated with the robotic surgical simulator instruments facilitated completion of the task by nonexperts. All platforms were perceived as effective training tools.

  8. Sophistication of computational science and fundamental physics simulations

    International Nuclear Information System (INIS)

    Ishiguro, Seiji; Ito, Atsushi; Usami, Shunsuke; Ohtani, Hiroaki; Sakagami, Hitoshi; Toida, Mieko; Hasegawa, Hiroki; Horiuchi, Ritoku; Miura, Hideaki

    2016-01-01

    Numerical experimental reactor research project is composed of the following studies: (1) nuclear fusion simulation research with a focus on specific physical phenomena of specific equipment, (2) research on advanced simulation method to increase predictability or expand its application range based on simulation, (3) visualization as the foundation of simulation research, (4) research for advanced computational science such as parallel computing technology, and (5) research aiming at elucidation of fundamental physical phenomena not limited to specific devices. Specifically, a wide range of researches with medium- to long-term perspectives are being developed: (1) virtual reality visualization, (2) upgrading of computational science such as multilayer simulation method, (3) kinetic behavior of plasma blob, (4) extended MHD theory and simulation, (5) basic plasma process such as particle acceleration due to interaction of wave and particle, and (6) research related to laser plasma fusion. This paper reviews the following items: (1) simultaneous visualization in virtual reality space, (2) multilayer simulation of collisionless magnetic reconnection, (3) simulation of microscopic dynamics of plasma coherent structure, (4) Hall MHD simulation of LHD, (5) numerical analysis for extension of MHD equilibrium and stability theory, (6) extended MHD simulation of 2D RT instability, (7) simulation of laser plasma, (8) simulation of shock wave and particle acceleration, and (9) study on simulation of homogeneous isotropic MHD turbulent flow. (A.O.)

  9. A review of virtual reality based training simulators for orthopaedic surgery.

    Science.gov (United States)

    Vaughan, Neil; Dubey, Venketesh N; Wainwright, Thomas W; Middleton, Robert G

    2016-02-01

    This review presents current virtual reality based training simulators for hip, knee and other orthopaedic surgery, including elective and trauma surgical procedures. There have not been any reviews focussing on hip and knee orthopaedic simulators. A comparison of existing simulator features is provided to identify what is missing and what is required to improve upon current simulators. In total 11 hip replacements pre-operative planning tools were analysed, plus 9 hip trauma fracture training simulators. Additionally 9 knee arthroscopy simulators and 8 other orthopaedic simulators were included for comparison. The findings are that for orthopaedic surgery simulators in general, there is increasing use of patient-specific virtual models which reduce the learning curve. Modelling is also being used for patient-specific implant design and manufacture. Simulators are being increasingly validated for assessment as well as training. There are very few training simulators available for hip replacement, yet more advanced virtual reality is being used for other procedures such as hip trauma and drilling. Training simulators for hip replacement and orthopaedic surgery in general lag behind other surgical procedures for which virtual reality has become more common. Further developments are required to bring hip replacement training simulation up to date with other procedures. This suggests there is a gap in the market for a new high fidelity hip replacement and resurfacing training simulator. Copyright © 2015 IPEM. Published by Elsevier Ltd. All rights reserved.

  10. Inovation of the computer system for the WWER-440 simulator

    International Nuclear Information System (INIS)

    Schrumpf, L.

    1988-01-01

    The configuration of the WWER-440 simulator computer system consists of four SMEP computers. The basic data processing unit consists of two interlinked SM 52/11.M1 computers with 1 MB of main memory. This part of the computer system of the simulator controls the operation of the entire simulator, processes the programs of technology behavior simulation, of the unit information system and of other special systems, guarantees program support and the operation of the instructor's console. An SM 52/11 computer with 256 kB of main memory is connected to each unit. It is used as a communication unit for data transmission using the DASIO 600 interface. Semigraphic color displays are based on the microprocessor modules of the SM 50/40 and SM 53/10 kit supplemented with a modified TESLA COLOR 110 ST tv receiver. (J.B.). 1 fig

  11. Radiotherapy Monte Carlo simulation using cloud computing technology.

    Science.gov (United States)

    Poole, C M; Cornelius, I; Trapp, J V; Langton, C M

    2012-12-01

    Cloud computing allows for vast computational resources to be leveraged quickly and easily in bursts as and when required. Here we describe a technique that allows for Monte Carlo radiotherapy dose calculations to be performed using GEANT4 and executed in the cloud, with relative simulation cost and completion time evaluated as a function of machine count. As expected, simulation completion time decreases as 1/n for n parallel machines, and relative simulation cost is found to be optimal where n is a factor of the total simulation time in hours. Using the technique, we demonstrate the potential usefulness of cloud computing as a solution for rapid Monte Carlo simulation for radiotherapy dose calculation without the need for dedicated local computer hardware as a proof of principal.

  12. Radiotherapy Monte Carlo simulation using cloud computing technology

    International Nuclear Information System (INIS)

    Poole, C.M.; Cornelius, I.; Trapp, J.V.; Langton, C.M.

    2012-01-01

    Cloud computing allows for vast computational resources to be leveraged quickly and easily in bursts as and when required. Here we describe a technique that allows for Monte Carlo radiotherapy dose calculations to be performed using GEANT4 and executed in the cloud, with relative simulation cost and completion time evaluated as a function of machine count. As expected, simulation completion time decreases as 1/n for n parallel machines, and relative simulation cost is found to be optimal where n is a factor of the total simulation time in hours. Using the technique, we demonstrate the potential usefulness of cloud computing as a solution for rapid Monte Carlo simulation for radiotherapy dose calculation without the need for dedicated local computer hardware as a proof of principal.

  13. Methodology of modeling and measuring computer architectures for plasma simulations

    Science.gov (United States)

    Wang, L. P. T.

    1977-01-01

    A brief introduction to plasma simulation using computers and the difficulties on currently available computers is given. Through the use of an analyzing and measuring methodology - SARA, the control flow and data flow of a particle simulation model REM2-1/2D are exemplified. After recursive refinements the total execution time may be greatly shortened and a fully parallel data flow can be obtained. From this data flow, a matched computer architecture or organization could be configured to achieve the computation bound of an application problem. A sequential type simulation model, an array/pipeline type simulation model, and a fully parallel simulation model of a code REM2-1/2D are proposed and analyzed. This methodology can be applied to other application problems which have implicitly parallel nature.

  14. Automated outcome scoring in a virtual reality simulator for endodontic surgery.

    Science.gov (United States)

    Yin, Myat Su; Haddawy, Peter; Suebnukarn, Siriwan; Rhienmora, Phattanapon

    2018-01-01

    We address the problem of automated outcome assessment in a virtual reality (VR) simulator for endodontic surgery. Outcome assessment is an essential component of any system that provides formative feedback, which requires assessing the outcome, relating it to the procedure, and communicating in a language natural to dental students. This study takes a first step toward automated generation of such comprehensive feedback. Virtual reference templates are computed based on tooth anatomy and the outcome is assessed with a 3D score cube volume which consists of voxel-level non-linear weighted scores based on the templates. The detailed scores are transformed into standard scoring language used by dental schools. The system was evaluated on fifteen outcome samples that contained optimal results and those with errors including perforation of the walls, floor, and both, as well as various combinations of major and minor over and under drilling errors. Five endodontists who had professional training and varying levels of experiences in root canal treatment participated as raters in the experiment. Results from evaluation of our system with expert endodontists show a high degree of agreement with expert scores (information based measure of disagreement 0.04-0.21). At the same time they show some disagreement among human expert scores, reflecting the subjective nature of human outcome scoring. The discriminatory power of the AOS scores analyzed with three grade tiers (A, B, C) using the area under the receiver operating characteristic curve (AUC). The AUC values are generally highest for the {AB: C} cutoff which is cutoff at the boundary between clinically acceptable (B) and clinically unacceptable (C) grades. The objective consistency of computed scores and high degree of agreement with experts make the proposed system a promising addition to existing VR simulators. The translation of detailed level scores into terminology commonly used in dental surgery supports natural

  15. A review of virtual reality based training simulators for orthopaedic surgery

    OpenAIRE

    Vaughan, Neil; Dubey, Venketesh N.; Wainwright, Tom; Middleton, Robert

    2015-01-01

    This review presents current virtual reality based training simulators for hip, knee and other orthopaedic surgery, including elective and trauma surgical procedures. There have not been any reviews focussing on hip and knee orthopaedic simulators. A comparison of existing simulator features is provided to identify what is missing and what is required to improve upon current simulators. In total 11 total hip replacement pre-operative planning tools were analysed, plus 9 hip trauma fracture tr...

  16. The benefit of non contrast-enhanced magnetic resonance angiography for predicting vascular access surgery outcome: a computer model perspective.

    Directory of Open Access Journals (Sweden)

    Maarten A G Merkx

    Full Text Available INTRODUCTION: Vascular access (VA surgery, a prerequisite for hemodialysis treatment of end-stage renal-disease (ESRD patients, is hampered by complication rates, which are frequently related to flow enhancement. To assist in VA surgery planning, a patient-specific computer model for postoperative flow enhancement was developed. The purpose of this study is to assess the benefit of non contrast-enhanced magnetic resonance angiography (NCE-MRA data as patient-specific geometrical input for the model-based prediction of surgery outcome. METHODS: 25 ESRD patients were included in this study. All patients received a NCE-MRA examination of the upper extremity blood vessels in addition to routine ultrasound (US. Local arterial radii were assessed from NCE-MRA and converted to model input using a linear fit per artery. Venous radii were determined with US. The effect of radius measurement uncertainty on model predictions was accounted for by performing Monte-Carlo simulations. The resulting flow prediction interval of the computer model was compared with the postoperative flow obtained from US. Patients with no overlap between model-based prediction and postoperative measurement were further analyzed to determine whether an increase in geometrical detail improved computer model prediction. RESULTS: Overlap between postoperative flows and model-based predictions was obtained for 71% of patients. Detailed inspection of non-overlapping cases revealed that the geometrical details that could be assessed from NCE-MRA explained most of the differences, and moreover, upon addition of these details in the computer model the flow predictions improved. CONCLUSIONS: The results demonstrate clearly that NCE-MRA does provide valuable geometrical information for VA surgery planning. Therefore, it is recommended to use this modality, at least for patients at risk for local or global narrowing of the blood vessels as well as for patients for whom an US-based model

  17. Computer Simulation of Angle-measuring System of Photoelectric Theodolite

    International Nuclear Information System (INIS)

    Zeng, L; Zhao, Z W; Song, S L; Wang, L T

    2006-01-01

    In this paper, a virtual test platform based on malfunction phenomena is designed, using the methods of computer simulation and numerical mask. It is used in the simulation training of angle-measuring system of photoelectric theodolite. Actual application proves that this platform supplies good condition for technicians making deep simulation training and presents a useful approach for the establishment of other large equipment simulation platforms

  18. Understanding Emergency Care Delivery Through Computer Simulation Modeling.

    Science.gov (United States)

    Laker, Lauren F; Torabi, Elham; France, Daniel J; Froehle, Craig M; Goldlust, Eric J; Hoot, Nathan R; Kasaie, Parastu; Lyons, Michael S; Barg-Walkow, Laura H; Ward, Michael J; Wears, Robert L

    2018-02-01

    In 2017, Academic Emergency Medicine convened a consensus conference entitled, "Catalyzing System Change through Health Care Simulation: Systems, Competency, and Outcomes." This article, a product of the breakout session on "understanding complex interactions through systems modeling," explores the role that computer simulation modeling can and should play in research and development of emergency care delivery systems. This article discusses areas central to the use of computer simulation modeling in emergency care research. The four central approaches to computer simulation modeling are described (Monte Carlo simulation, system dynamics modeling, discrete-event simulation, and agent-based simulation), along with problems amenable to their use and relevant examples to emergency care. Also discussed is an introduction to available software modeling platforms and how to explore their use for research, along with a research agenda for computer simulation modeling. Through this article, our goal is to enhance adoption of computer simulation, a set of methods that hold great promise in addressing emergency care organization and design challenges. © 2017 by the Society for Academic Emergency Medicine.

  19. Humans, computers and wizards human (simulated) computer interaction

    CERN Document Server

    Fraser, Norman; McGlashan, Scott; Wooffitt, Robin

    2013-01-01

    Using data taken from a major European Union funded project on speech understanding, the SunDial project, this book considers current perspectives on human computer interaction and argues for the value of an approach taken from sociology which is based on conversation analysis.

  20. Computer Simulation Studies of Trishomocubane Heptapeptide of ...

    African Journals Online (AJOL)

    NICO

    Trishomocubane, molecular dynamics, Amber, CLASICO, β-turn, α-helical. 1. Introduction .... MD simulations of Ac-Ala3-Tris-Ala3-NHMe explicitly in MEOH. 3. Results and .... worthwhile to group all conformations into clusters according to.

  1. Tolerance analysis through computational imaging simulations

    Science.gov (United States)

    Birch, Gabriel C.; LaCasse, Charles F.; Stubbs, Jaclynn J.; Dagel, Amber L.; Bradley, Jon

    2017-11-01

    The modeling and simulation of non-traditional imaging systems require holistic consideration of the end-to-end system. We demonstrate this approach through a tolerance analysis of a random scattering lensless imaging system.

  2. Computed radiography simulation using the Monte Carlo code MCNPX

    International Nuclear Information System (INIS)

    Correa, S.C.A.; Souza, E.M.; Silva, A.X.; Lopes, R.T.

    2009-01-01

    Simulating x-ray images has been of great interest in recent years as it makes possible an analysis of how x-ray images are affected owing to relevant operating parameters. In this paper, a procedure for simulating computed radiographic images using the Monte Carlo code MCNPX is proposed. The sensitivity curve of the BaFBr image plate detector as well as the characteristic noise of a 16-bit computed radiography system were considered during the methodology's development. The results obtained confirm that the proposed procedure for simulating computed radiographic images is satisfactory, as it allows obtaining results comparable with experimental data. (author)

  3. Large-scale computing techniques for complex system simulations

    CERN Document Server

    Dubitzky, Werner; Schott, Bernard

    2012-01-01

    Complex systems modeling and simulation approaches are being adopted in a growing number of sectors, including finance, economics, biology, astronomy, and many more. Technologies ranging from distributed computing to specialized hardware are explored and developed to address the computational requirements arising in complex systems simulations. The aim of this book is to present a representative overview of contemporary large-scale computing technologies in the context of complex systems simulations applications. The intention is to identify new research directions in this field and

  4. Computer Simulation Performed for Columbia Project Cooling System

    Science.gov (United States)

    Ahmad, Jasim

    2005-01-01

    This demo shows a high-fidelity simulation of the air flow in the main computer room housing the Columbia (10,024 intel titanium processors) system. The simulation asseses the performance of the cooling system and identified deficiencies, and recommended modifications to eliminate them. It used two in house software packages on NAS supercomputers: Chimera Grid tools to generate a geometric model of the computer room, OVERFLOW-2 code for fluid and thermal simulation. This state-of-the-art technology can be easily extended to provide a general capability for air flow analyses on any modern computer room. Columbia_CFD_black.tiff

  5. Computed radiography simulation using the Monte Carlo code MCNPX

    Energy Technology Data Exchange (ETDEWEB)

    Correa, S.C.A. [Programa de Engenharia Nuclear/COPPE, Universidade Federal do Rio de Janeiro, Ilha do Fundao, Caixa Postal 68509, 21945-970, Rio de Janeiro, RJ (Brazil); Centro Universitario Estadual da Zona Oeste (CCMAT)/UEZO, Av. Manuel Caldeira de Alvarenga, 1203, Campo Grande, 23070-200, Rio de Janeiro, RJ (Brazil); Souza, E.M. [Programa de Engenharia Nuclear/COPPE, Universidade Federal do Rio de Janeiro, Ilha do Fundao, Caixa Postal 68509, 21945-970, Rio de Janeiro, RJ (Brazil); Silva, A.X., E-mail: ademir@con.ufrj.b [PEN/COPPE-DNC/Poli CT, Universidade Federal do Rio de Janeiro, Ilha do Fundao, Caixa Postal 68509, 21945-970, Rio de Janeiro, RJ (Brazil); Cassiano, D.H. [Instituto de Radioprotecao e Dosimetria/CNEN Av. Salvador Allende, s/n, Recreio, 22780-160, Rio de Janeiro, RJ (Brazil); Lopes, R.T. [Programa de Engenharia Nuclear/COPPE, Universidade Federal do Rio de Janeiro, Ilha do Fundao, Caixa Postal 68509, 21945-970, Rio de Janeiro, RJ (Brazil)

    2010-09-15

    Simulating X-ray images has been of great interest in recent years as it makes possible an analysis of how X-ray images are affected owing to relevant operating parameters. In this paper, a procedure for simulating computed radiographic images using the Monte Carlo code MCNPX is proposed. The sensitivity curve of the BaFBr image plate detector as well as the characteristic noise of a 16-bit computed radiography system were considered during the methodology's development. The results obtained confirm that the proposed procedure for simulating computed radiographic images is satisfactory, as it allows obtaining results comparable with experimental data.

  6. Grid desktop computing for constructive battlefield simulation

    OpenAIRE

    Repetto, Alejandro Juan Manuel

    2009-01-01

    It is a fact that gaming technology is a state-of-the-art tool for military training, not only in low level simulations, e.g. flight training simulations, but also for strategic and tactical training. It is also a fact that users of this kind of technologies require increasingly more realistic representations of the real world. This functional reality threatens both hardware and software capabilities, making almost impossible to keep up with the requirements. Many optimizations have been perf...

  7. Current status of validation for robotic surgery simulators - a systematic review.

    Science.gov (United States)

    Abboudi, Hamid; Khan, Mohammed S; Aboumarzouk, Omar; Guru, Khurshid A; Challacombe, Ben; Dasgupta, Prokar; Ahmed, Kamran

    2013-02-01

    To analyse studies validating the effectiveness of robotic surgery simulators. The MEDLINE(®), EMBASE(®) and PsycINFO(®) databases were systematically searched until September 2011. References from retrieved articles were reviewed to broaden the search. The simulator name, training tasks, participant level, training duration and evaluation scoring were extracted from each study. We also extracted data on feasibility, validity, cost-effectiveness, reliability and educational impact. We identified 19 studies investigating simulation options in robotic surgery. There are five different robotic surgery simulation platforms available on the market. In all, 11 studies sought opinion and compared performance between two different groups; 'expert' and 'novice'. Experts ranged in experience from 21-2200 robotic cases. The novice groups consisted of participants with no prior experience on a robotic platform and were often medical students or junior doctors. The Mimic dV-Trainer(®), ProMIS(®), SimSurgery Educational Platform(®) (SEP) and Intuitive systems have shown face, content and construct validity. The Robotic Surgical SimulatorTM system has only been face and content validated. All of the simulators except SEP have shown educational impact. Feasibility and cost-effectiveness of simulation systems was not evaluated in any trial. Virtual reality simulators were shown to be effective training tools for junior trainees. Simulation training holds the greatest potential to be used as an adjunct to traditional training methods to equip the next generation of robotic surgeons with the skills required to operate safely. However, current simulation models have only been validated in small studies. There is no evidence to suggest one type of simulator provides more effective training than any other. More research is needed to validate simulated environments further and investigate the effectiveness of animal and cadaveric training in robotic surgery. © 2012 BJU

  8. How Many Times Should One Run a Computational Simulation?

    DEFF Research Database (Denmark)

    Seri, Raffaello; Secchi, Davide

    2017-01-01

    This chapter is an attempt to answer the question “how many runs of a computational simulation should one do,” and it gives an answer by means of statistical analysis. After defining the nature of the problem and which types of simulation are mostly affected by it, the article introduces statisti......This chapter is an attempt to answer the question “how many runs of a computational simulation should one do,” and it gives an answer by means of statistical analysis. After defining the nature of the problem and which types of simulation are mostly affected by it, the article introduces...

  9. Biocellion: accelerating computer simulation of multicellular biological system models.

    Science.gov (United States)

    Kang, Seunghwa; Kahan, Simon; McDermott, Jason; Flann, Nicholas; Shmulevich, Ilya

    2014-11-01

    Biological system behaviors are often the outcome of complex interactions among a large number of cells and their biotic and abiotic environment. Computational biologists attempt to understand, predict and manipulate biological system behavior through mathematical modeling and computer simulation. Discrete agent-based modeling (in combination with high-resolution grids to model the extracellular environment) is a popular approach for building biological system models. However, the computational complexity of this approach forces computational biologists to resort to coarser resolution approaches to simulate large biological systems. High-performance parallel computers have the potential to address the computing challenge, but writing efficient software for parallel computers is difficult and time-consuming. We have developed Biocellion, a high-performance software framework, to solve this computing challenge using parallel computers. To support a wide range of multicellular biological system models, Biocellion asks users to provide their model specifics by filling the function body of pre-defined model routines. Using Biocellion, modelers without parallel computing expertise can efficiently exploit parallel computers with less effort than writing sequential programs from scratch. We simulate cell sorting, microbial patterning and a bacterial system in soil aggregate as case studies. Biocellion runs on x86 compatible systems with the 64 bit Linux operating system and is freely available for academic use. Visit http://biocellion.com for additional information. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  10. Multi-slice computed tomography-assisted endoscopic transsphenoidal surgery for pituitary macroadenoma: a comparison with conventional microscopic transsphenoidal surgery.

    Science.gov (United States)

    Tosaka, Masahiko; Nagaki, Tomohito; Honda, Fumiaki; Takahashi, Katsumasa; Yoshimoto, Yuhei

    2015-11-01

    Intraoperative computed tomography (iCT) is a reliable method for the detection of residual tumour, but previous single-slice low-resolution computed tomography (CT) without coronal or sagittal reconstructions was not of adequate quality for clinical use. The present study evaluated the results of multi-slice iCT-assisted endoscopic transsphenoidal surgery for pituitary macroadenoma. This retrospective study included 30 consecutive patients with newly diagnosed or recurrent pituitary macroadenoma with supradiaphragmatic extension who underwent endoscopic transsphenoidal surgery using iCT (eTSS+iCT group), and control 30 consecutive patients who underwent conventional endoscope-assisted transsphenoidal surgery (cTSS group). The tumour volume was calculated by multiplying the tumour area by the slice thickness. Visual acuity and visual field were estimated by the visual impairment score (VIS). The resection extent, (preoperative tumour volume - postoperative residual tumour volume)/preoperative tumour volume, was 98.9% (median) in the eTSS+iCT group and 91.7% in the cTSS group, and had significant difference between the groups (P = 0.04). Greater than 95 and >90% removal rates were significantly higher in the eTSS+iCT group than in the cTSS group (P = 0.02 and P = 0.001, respectively). However, improvement in VIS showed no significant difference between the groups. The rate of complications also showed no significant difference. Multi-slice iCT-assisted endoscopic transsphenoidal surgery may improve the resection extent of pituitary macroadenoma. Multi-slice iCT may have advantages over intraoperative magnetic resonance imaging in less expensive, short acquisition time, and that special protection against magnetic fields is not needed.

  11. On architectural acoustic design using computer simulation

    DEFF Research Database (Denmark)

    Schmidt, Anne Marie Due; Kirkegaard, Poul Henning

    2004-01-01

    properties prior to the actual construction of a building. With the right tools applied, acoustic design can become an integral part of the architectural design process. The aim of this paper is to investigate the field of application that an acoustic simulation programme can have during an architectural...... acoustic design process. The emphasis is put on the first three out of five phases in the working process of the architect and a case study is carried out in which each phase is represented by typical results ? as exemplified with reference to the design of Bagsværd Church by Jørn Utzon. The paper...... discusses the advantages and disadvantages of the programme in each phase compared to the works of architects not using acoustic simulation programmes. The conclusion of the paper is that the application of acoustic simulation programs is most beneficial in the last of three phases but an application...

  12. Computer simulation of auroral kilometric radiation

    International Nuclear Information System (INIS)

    Wagner, J.S.; Tajima, T.; Lee, L.C.; Wu, C.S.

    1983-01-01

    We study the generation of auroral kilometric radiation (AKR) using relativistic, electromagnetic, particle simulations. The AKR source region is modeled by two electron populations in the simulation: a cold (200 eV) Maxwellian component and a hot (5-20 keV) population possessing a loss-cone feature. The loss cone distribution is found to be unstable to the cyclotron maser instability. The fast extraordinary (X-mode) waves dominate the radiation and saturate when resonant particles diffuse into the loss-cone via turbulent scattering of the particles by the amplified X-mode radiation

  13. Real-time volumetric deformable models for surgery simulation using finite elements and condensation

    DEFF Research Database (Denmark)

    Bro-Nielsen, Morten; Cotin, S.

    1996-01-01

    This paper discusses the application of SD solid volumetric Finite Element models to surgery simulation. In particular it introduces three new ideas for solving the problem of achieving real-time performance for these models. The simulation system we have developed is described and we demonstrate...

  14. Tutorial: Parallel Computing of Simulation Models for Risk Analysis.

    Science.gov (United States)

    Reilly, Allison C; Staid, Andrea; Gao, Michael; Guikema, Seth D

    2016-10-01

    Simulation models are widely used in risk analysis to study the effects of uncertainties on outcomes of interest in complex problems. Often, these models are computationally complex and time consuming to run. This latter point may be at odds with time-sensitive evaluations or may limit the number of parameters that are considered. In this article, we give an introductory tutorial focused on parallelizing simulation code to better leverage modern computing hardware, enabling risk analysts to better utilize simulation-based methods for quantifying uncertainty in practice. This article is aimed primarily at risk analysts who use simulation methods but do not yet utilize parallelization to decrease the computational burden of these models. The discussion is focused on conceptual aspects of embarrassingly parallel computer code and software considerations. Two complementary examples are shown using the languages MATLAB and R. A brief discussion of hardware considerations is located in the Appendix. © 2016 Society for Risk Analysis.

  15. Development of a Virtual Reality Simulator for Natural Orifice Translumenal Endoscopic Surgery (NOTES) Cholecystectomy Procedure.

    Science.gov (United States)

    Ahn, Woojin; Dargar, Saurabh; Halic, Tansel; Lee, Jason; Li, Baichun; Pan, Junjun; Sankaranarayanan, Ganesh; Roberts, Kurt; De, Suvranu

    2014-01-01

    The first virtual-reality-based simulator for Natural Orifice Translumenal Endoscopic Surgery (NOTES) is developed called the Virtual Translumenal Endoscopic Surgery Trainer (VTESTTM). VTESTTM aims to simulate hybrid NOTES cholecystectomy procedure using a rigid scope inserted through the vaginal port. The hardware interface is designed for accurate motion tracking of the scope and laparoscopic instruments to reproduce the unique hand-eye coordination. The haptic-enabled multimodal interactive simulation includes exposing the Calot's triangle and detaching the gall bladder while performing electrosurgery. The developed VTESTTM was demonstrated and validated at NOSCAR 2013.

  16. A cost effective and high fidelity fluoroscopy simulator using the Image-Guided Surgery Toolkit (IGSTK)

    Science.gov (United States)

    Gong, Ren Hui; Jenkins, Brad; Sze, Raymond W.; Yaniv, Ziv

    2014-03-01

    The skills required for obtaining informative x-ray fluoroscopy images are currently acquired while trainees provide clinical care. As a consequence, trainees and patients are exposed to higher doses of radiation. Use of simulation has the potential to reduce this radiation exposure by enabling trainees to improve their skills in a safe environment prior to treating patients. We describe a low cost, high fidelity, fluoroscopy simulation system. Our system enables operators to practice their skills using the clinical device and simulated x-rays of a virtual patient. The patient is represented using a set of temporal Computed Tomography (CT) images, corresponding to the underlying dynamic processes. Simulated x-ray images, digitally reconstructed radiographs (DRRs), are generated from the CTs using ray-casting with customizable machine specific imaging parameters. To establish the spatial relationship between the CT and the fluoroscopy device, the CT is virtually attached to a patient phantom and a web camera is used to track the phantom's pose. The camera is mounted on the fluoroscope's intensifier and the relationship between it and the x-ray source is obtained via calibration. To control image acquisition the operator moves the fluoroscope as in normal operation mode. Control of zoom, collimation and image save is done using a keypad mounted alongside the device's control panel. Implementation is based on the Image-Guided Surgery Toolkit (IGSTK), and the use of the graphics processing unit (GPU) for accelerated image generation. Our system was evaluated by 11 clinicians and was found to be sufficiently realistic for training purposes.

  17. Comparison of radiographic technique by computer simulation

    International Nuclear Information System (INIS)

    Brochi, M.A.C.; Ghilardi Neto, T.

    1989-01-01

    A computational algorithm to compare radiographic techniques (KVp, mAs and filters) is developed based in the fixation of parameters that defines the images, such as optical density and constrast. Before the experience, the results were used in a radiography of thorax. (author) [pt

  18. Computational Dehydration of Crystalline Hydrates Using Molecular Dynamics Simulations

    DEFF Research Database (Denmark)

    Larsen, Anders Støttrup; Rantanen, Jukka; Johansson, Kristoffer E

    2017-01-01

    Molecular dynamics (MD) simulations have evolved to an increasingly reliable and accessible technique and are today implemented in many areas of biomedical sciences. We present a generally applicable method to study dehydration of hydrates based on MD simulations and apply this approach...... to the dehydration of ampicillin trihydrate. The crystallographic unit cell of the trihydrate is used to construct the simulation cell containing 216 ampicillin and 648 water molecules. This system is dehydrated by removing water molecules during a 2200 ps simulation, and depending on the computational dehydration....... The structural changes could be followed in real time, and in addition, an intermediate amorphous phase was identified. The computationally identified dehydrated structure (anhydrate) was slightly different from the experimentally known anhydrate structure suggesting that the simulated computational structure...

  19. Understanding Islamist political violence through computational social simulation

    Energy Technology Data Exchange (ETDEWEB)

    Watkins, Jennifer H [Los Alamos National Laboratory; Mackerrow, Edward P [Los Alamos National Laboratory; Patelli, Paolo G [Los Alamos National Laboratory; Eberhardt, Ariane [Los Alamos National Laboratory; Stradling, Seth G [Los Alamos National Laboratory

    2008-01-01

    Understanding the process that enables political violence is of great value in reducing the future demand for and support of violent opposition groups. Methods are needed that allow alternative scenarios and counterfactuals to be scientifically researched. Computational social simulation shows promise in developing 'computer experiments' that would be unfeasible or unethical in the real world. Additionally, the process of modeling and simulation reveals and challenges assumptions that may not be noted in theories, exposes areas where data is not available, and provides a rigorous, repeatable, and transparent framework for analyzing the complex dynamics of political violence. This paper demonstrates the computational modeling process using two simulation techniques: system dynamics and agent-based modeling. The benefits and drawbacks of both techniques are discussed. In developing these social simulations, we discovered that the social science concepts and theories needed to accurately simulate the associated psychological and social phenomena were lacking.

  20. Multidimensional computer simulation of Stirling cycle engines

    Science.gov (United States)

    Hall, Charles A.; Porsching, Thomas A.

    1992-01-01

    This report summarizes the activities performed under NASA-Grant NAG3-1097 during 1991. During that period, work centered on the following tasks: (1) to investigate more effective solvers for ALGAE; (2) to modify the plotting package for ALGAE; and (3) to validate ALGAE by simulating oscillating flow problems similar to those studied by Kurzweg and Ibrahim.

  1. Computer Simulation Studies of Trishomocubane Heptapeptide of ...

    African Journals Online (AJOL)

    As part of an extension on the cage peptide chemistry, the present work involves an assessment of the conformational profile of trishomocubane heptapeptide of the type Ac-Ala3-Tris-Ala3-NHMe using molecular dynamics (MD) simulations. All MD protocols were explored within the framework of a molecular mechanics ...

  2. Advanced Simulation and Computing Business Plan

    Energy Technology Data Exchange (ETDEWEB)

    Rummel, E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-07-09

    To maintain a credible nuclear weapons program, the National Nuclear Security Administration’s (NNSA’s) Office of Defense Programs (DP) needs to make certain that the capabilities, tools, and expert staff are in place and are able to deliver validated assessments. This requires a complete and robust simulation environment backed by an experimental program to test ASC Program models. This ASC Business Plan document encapsulates a complex set of elements, each of which is essential to the success of the simulation component of the Nuclear Security Enterprise. The ASC Business Plan addresses the hiring, mentoring, and retaining of programmatic technical staff responsible for building the simulation tools of the nuclear security complex. The ASC Business Plan describes how the ASC Program engages with industry partners—partners upon whom the ASC Program relies on for today’s and tomorrow’s high performance architectures. Each piece in this chain is essential to assure policymakers, who must make decisions based on the results of simulations, that they are receiving all the actionable information they need.

  3. Role of computational efficiency in process simulation

    Directory of Open Access Journals (Sweden)

    Kurt Strand

    1989-07-01

    Full Text Available It is demonstrated how efficient numerical algorithms may be combined to yield a powerful environment for analysing and simulating dynamic systems. The importance of using efficient numerical algorithms is emphasized and demonstrated through examples from the petrochemical industry.

  4. Computer simulation of confined liquid crystal dynamics

    International Nuclear Information System (INIS)

    Webster, R.E.

    2001-11-01

    Results are presented from a series of simulations undertaken to determine whether dynamic processes observed in device-scale liquid crystal cells confined between aligning substrates can be simulated in a molecular system using parallel molecular dynamics of the Gay-Berne model. In a nematic cell, on removal of an aligning field, initial near-surface director relaxation can induce flow, termed 'backflow' in the liquid. This, in turn, can cause director rotation, termed 'orientational kickback', in the centre of the cell. Simulations are performed of the relaxation in nematic systems confined between substrates with a common alignment on removal of an aligning field. Results show /that relaxation timescales of medium sized systems are accessible. Following this, simulations are performed of relaxation in hybrid aligned nematic systems, where each surface induces a different alignment. Flow patterns associated with director reorientation are observed. The damped oscillatory nature of the relaxation process suggests that the behaviour of these systems is dominated by orientational elastic forces and that the observed director motion and flow do not correspond to the macroscopic processes of backflow and kickback. Chevron structures can occur in confined smectic cells which develop two domains of equal and opposite layer tilt on cooling. Layer lilting is thought to be caused by a need to reconcile a mismatch between bulk and surface smectic layer spacing. Here, simulations are performed of the formation of structures in confined smectic systems where layer tilt is induced by an imposed surface pretilt. Results show that bookshelf, chevron and tilled layer structures are observable in a confined Gay-Berne system. The formation and stability of the chevron structure are shown to be influenced by surface slip. (author)

  5. Computer simulation of confined liquid crystal dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Webster, R.E

    2001-11-01

    Results are presented from a series of simulations undertaken to determine whether dynamic processes observed in device-scale liquid crystal cells confined between aligning substrates can be simulated in a molecular system using parallel molecular dynamics of the Gay-Berne model. In a nematic cell, on removal of an aligning field, initial near-surface director relaxation can induce flow, termed 'backflow' in the liquid. This, in turn, can cause director rotation, termed 'orientational kickback', in the centre of the cell. Simulations are performed of the relaxation in nematic systems confined between substrates with a common alignment on removal of an aligning field. Results show /that relaxation timescales of medium sized systems are accessible. Following this, simulations are performed of relaxation in hybrid aligned nematic systems, where each surface induces a different alignment. Flow patterns associated with director reorientation are observed. The damped oscillatory nature of the relaxation process suggests that the behaviour of these systems is dominated by orientational elastic forces and that the observed director motion and flow do not correspond to the macroscopic processes of backflow and kickback. Chevron structures can occur in confined smectic cells which develop two domains of equal and opposite layer tilt on cooling. Layer lilting is thought to be caused by a need to reconcile a mismatch between bulk and surface smectic layer spacing. Here, simulations are performed of the formation of structures in confined smectic systems where layer tilt is induced by an imposed surface pretilt. Results show that bookshelf, chevron and tilled layer structures are observable in a confined Gay-Berne system. The formation and stability of the chevron structure are shown to be influenced by surface slip. (author)

  6. Easy computer assisted teaching method for undergraduate surgery

    OpenAIRE

    Agrawal, Vijay P

    2015-01-01

    Use of computers to aid or support the education or training of people has become commonplace in medical education. Recent studies have shown that it can improve learning outcomes in diagnostic abilities, clinical skills and knowledge across different learner levels from undergraduate medical education to continuing medical education. It also enhance the educational process by increasing access to learning materials, standardising the educational process, providing opportunities for asynchron...

  7. Launch Site Computer Simulation and its Application to Processes

    Science.gov (United States)

    Sham, Michael D.

    1995-01-01

    This paper provides an overview of computer simulation, the Lockheed developed STS Processing Model, and the application of computer simulation to a wide range of processes. The STS Processing Model is an icon driven model that uses commercial off the shelf software and a Macintosh personal computer. While it usually takes one year to process and launch 8 space shuttles, with the STS Processing Model this process is computer simulated in about 5 minutes. Facilities, orbiters, or ground support equipment can be added or deleted and the impact on launch rate, facility utilization, or other factors measured as desired. This same computer simulation technology can be used to simulate manufacturing, engineering, commercial, or business processes. The technology does not require an 'army' of software engineers to develop and operate, but instead can be used by the layman with only a minimal amount of training. Instead of making changes to a process and realizing the results after the fact, with computer simulation, changes can be made and processes perfected before they are implemented.

  8. Quantum chemistry simulation on quantum computers: theories and experiments.

    Science.gov (United States)

    Lu, Dawei; Xu, Boruo; Xu, Nanyang; Li, Zhaokai; Chen, Hongwei; Peng, Xinhua; Xu, Ruixue; Du, Jiangfeng

    2012-07-14

    It has been claimed that quantum computers can mimic quantum systems efficiently in the polynomial scale. Traditionally, those simulations are carried out numerically on classical computers, which are inevitably confronted with the exponential growth of required resources, with the increasing size of quantum systems. Quantum computers avoid this problem, and thus provide a possible solution for large quantum systems. In this paper, we first discuss the ideas of quantum simulation, the background of quantum simulators, their categories, and the development in both theories and experiments. We then present a brief introduction to quantum chemistry evaluated via classical computers followed by typical procedures of quantum simulation towards quantum chemistry. Reviewed are not only theoretical proposals but also proof-of-principle experimental implementations, via a small quantum computer, which include the evaluation of the static molecular eigenenergy and the simulation of chemical reaction dynamics. Although the experimental development is still behind the theory, we give prospects and suggestions for future experiments. We anticipate that in the near future quantum simulation will become a powerful tool for quantum chemistry over classical computations.

  9. Towards computer-assisted surgery in shoulder joint replacement

    Science.gov (United States)

    Valstar, Edward R.; Botha, Charl P.; van der Glas, Marjolein; Rozing, Piet M.; van der Helm, Frans C. T.; Post, Frits H.; Vossepoel, Albert M.

    A research programme that aims to improve the state of the art in shoulder joint replacement surgery has been initiated at the Delft University of Technology. Development of improved endoprostheses for the upper extremities (DIPEX), as this effort is called, is a clinically driven multidisciplinary programme consisting of many contributory aspects. A part of this research programme focuses on the pre-operative planning and per-operative guidance issues. The ultimate goal of this part of the DIPEX project is to create a surgical support infrastructure that can be used to predict the optimal surgical protocol and can assist with the selection of the most suitable endoprosthesis for a particular patient. In the pre-operative planning phase, advanced biomechanical models of the endoprosthesis fixation and the musculo-skeletal system of the shoulder will be incorporated, which are adjusted to the individual's morphology. Subsequently, the support infrastructure must assist the surgeon during the operation in executing his surgical plan. In the per-operative phase, the chosen optimal position of the endoprosthesis can be realised using camera-assisted tools or mechanical guidance tools. In this article, the pathway towards the desired surgical support infrastructure is described. Furthermore, we discuss the pre-operative planning phase and the per-operative guidance phase, the initial work performed, and finally, possible approaches for improving prosthesis placement.

  10. Current state of virtual reality simulation in robotic surgery training: a review.

    Science.gov (United States)

    Bric, Justin D; Lumbard, Derek C; Frelich, Matthew J; Gould, Jon C

    2016-06-01

    Worldwide, the annual number of robotic surgical procedures continues to increase. Robotic surgical skills are unique from those used in either open or laparoscopic surgery. The acquisition of a basic robotic surgical skill set may be best accomplished in the simulation laboratory. We sought to review the current literature pertaining to the use of virtual reality (VR) simulation in the acquisition of robotic surgical skills on the da Vinci Surgical System. A PubMed search was conducted between December 2014 and January 2015 utilizing the following keywords: virtual reality, robotic surgery, da Vinci, da Vinci skills simulator, SimSurgery Educational Platform, Mimic dV-Trainer, and Robotic Surgery Simulator. Articles were included if they were published between 2007 and 2015, utilized VR simulation for the da Vinci Surgical System, and utilized a commercially available VR platform. The initial search criteria returned 227 published articles. After all inclusion and exclusion criteria were applied, a total of 47 peer-reviewed manuscripts were included in the final review. There are many benefits to utilizing VR simulation for robotic skills acquisition. Four commercially available simulators have been demonstrated to be capable of assessing robotic skill. Three of the four simulators demonstrate the ability of a VR training curriculum to improve basic robotic skills, with proficiency-based training being the most effective training style. The skills obtained on a VR training curriculum are comparable with those obtained on dry laboratory simulation. The future of VR simulation includes utilization in assessment for re-credentialing purposes, advanced procedural-based training, and as a warm-up tool prior to surgery.

  11. Development and implementation of a clinical pathway approach to simulation-based training for foregut surgery.

    Science.gov (United States)

    Miyasaka, Kiyoyuki W; Buchholz, Joseph; LaMarra, Denise; Karakousis, Giorgos C; Aggarwal, Rajesh

    2015-01-01

    Contemporary demands on resident education call for integration of simulation. We designed and implemented a simulation-based curriculum for Post Graduate Year 1 surgery residents to teach technical and nontechnical skills within a clinical pathway approach for a foregut surgery patient, from outpatient visit through surgery and postoperative follow-up. The 3-day curriculum for groups of 6 residents comprises a combination of standardized patient encounters, didactic sessions, and hands-on training. The curriculum is underpinned by a summative simulation "pathway" repeated on days 1 and 3. The "pathway" is a series of simulated preoperative, intraoperative, and postoperative encounters in following up a single patient through a disease process. The resident sees a standardized patient in the clinic presenting with distal gastric cancer and then enters an operating room to perform a gastrojejunostomy on a porcine tissue model. Finally, the resident engages in a simulated postoperative visit. All encounters are rated by faculty members and the residents themselves, using standardized assessment forms endorsed by the American Board of Surgery. A total of 18 first-year residents underwent this curriculum. Faculty ratings of overall operative performance significantly improved following the 3-day module. Ratings of preoperative and postoperative performance were not significantly changed in 3 days. Resident self-ratings significantly improved for all encounters assessed, as did reported confidence in meeting the defined learning objectives. Conventional surgical simulation training focuses on technical skills in isolation. Our novel "pathway" curriculum targets an important gap in training methodologies by placing both technical and nontechnical skills in their clinical context as part of managing a surgical patient. Results indicate consistent improvements in assessments of performance as well as confidence and support its continued usage to educate surgery residents

  12. Monte Carlo simulations on SIMD computer architectures

    International Nuclear Information System (INIS)

    Burmester, C.P.; Gronsky, R.; Wille, L.T.

    1992-01-01

    In this paper algorithmic considerations regarding the implementation of various materials science applications of the Monte Carlo technique to single instruction multiple data (SIMD) computer architectures are presented. In particular, implementation of the Ising model with nearest, next nearest, and long range screened Coulomb interactions on the SIMD architecture MasPar MP-1 (DEC mpp-12000) series of massively parallel computers is demonstrated. Methods of code development which optimize processor array use and minimize inter-processor communication are presented including lattice partitioning and the use of processor array spanning tree structures for data reduction. Both geometric and algorithmic parallel approaches are utilized. Benchmarks in terms of Monte Carl updates per second for the MasPar architecture are presented and compared to values reported in the literature from comparable studies on other architectures

  13. On Architectural Acoustics Design using Computer Simulation

    DEFF Research Database (Denmark)

    Schmidt, Anne Marie Due; Kirkegaard, Poul Henning

    2004-01-01

    The acoustical quality of a given building, or space within the building, is highly dependent on the architectural design. Architectural acoustics design has in the past been based on simple design rules. However, with a growing complexity in the architectural acoustic and the emergence of potent...... room acoustic simulation programs it is now possible to subjectively analyze and evaluate acoustic properties prior to the actual construction of a facility. With the right tools applied, the acoustic design can become an integrated part of the architectural design process. The aim of the present paper...... this information is discussed. The conclusion of the paper is that the application of acoustical simulation programs is most beneficial in the last of three phases but that an application of the program to the two first phases would be preferable and possible with an improvement of the interface of the program....

  14. Assessing Practical Skills in Physics Using Computer Simulations

    Science.gov (United States)

    Walsh, Kevin

    2018-01-01

    Computer simulations have been used very effectively for many years in the teaching of science but the focus has been on cognitive development. This study, however, is an investigation into the possibility that a student's experimental skills in the real-world environment can be judged via the undertaking of a suitably chosen computer simulation…

  15. Effect of computer game playing on baseline laparoscopic simulator skills.

    Science.gov (United States)

    Halvorsen, Fredrik H; Cvancarova, Milada; Fosse, Erik; Mjåland, Odd

    2013-08-01

    Studies examining the possible association between computer game playing and laparoscopic performance in general have yielded conflicting results and neither has a relationship between computer game playing and baseline performance on laparoscopic simulators been established. The aim of this study was to examine the possible association between previous and present computer game playing and baseline performance on a virtual reality laparoscopic performance in a sample of potential future medical students. The participating students completed a questionnaire covering the weekly amount and type of computer game playing activity during the previous year and 3 years ago. They then performed 2 repetitions of 2 tasks ("gallbladder dissection" and "traverse tube") on a virtual reality laparoscopic simulator. Performance on the simulator were then analyzed for association to their computer game experience. Local high school, Norway. Forty-eight students from 2 high school classes volunteered to participate in the study. No association between prior and present computer game playing and baseline performance was found. The results were similar both for prior and present action game playing and prior and present computer game playing in general. Our results indicate that prior and present computer game playing may not affect baseline performance in a virtual reality simulator.

  16. Computer Simulation of Turbulent Reactive Gas Dynamics

    Directory of Open Access Journals (Sweden)

    Bjørn H. Hjertager

    1984-10-01

    Full Text Available A simulation procedure capable of handling transient compressible flows involving combustion is presented. The method uses the velocity components and pressure as primary flow variables. The differential equations governing the flow are discretized by integration over control volumes. The integration is performed by application of up-wind differencing in a staggered grid system. The solution procedure is an extension of the SIMPLE-algorithm accounting for compressibility effects.

  17. Computer simulation of pitting potential measurements

    International Nuclear Information System (INIS)

    Laycock, N.J.; Noh, J.S.; White, S.P.; Krouse, D.P.

    2005-01-01

    A deterministic model for the growth of single pits in stainless steel has been combined with a purely stochastic model of pit nucleation. Monte-Carlo simulations have been used to compare the predictions of this model with potentiodynamic experimental measurements of the pitting potential. The quantitative agreement between model and experiment is reasonable for both 304 and 316 stainless steel, and the effects of varying surface roughness, solution chloride concentration and potential sweep rate have been considered

  18. Computational fluid dynamics (CFD) simulation of hot air flow ...

    African Journals Online (AJOL)

    Computational Fluid Dynamics simulation of air flow distribution, air velocity and pressure field pattern as it will affect moisture transient in a cabinet tray dryer is performed using SolidWorks Flow Simulation (SWFS) 2014 SP 4.0 program. The model used for the drying process in this experiment was designed with Solid ...

  19. Computer simulation of the NASA water vapor electrolysis reactor

    Science.gov (United States)

    Bloom, A. M.

    1974-01-01

    The water vapor electrolysis (WVE) reactor is a spacecraft waste reclamation system for extended-mission manned spacecraft. The WVE reactor's raw material is water, its product oxygen. A computer simulation of the WVE operational processes provided the data required for an optimal design of the WVE unit. The simulation process was implemented with the aid of a FORTRAN IV routine.

  20. Simulation of Robot Kinematics Using Interactive Computer Graphics.

    Science.gov (United States)

    Leu, M. C.; Mahajan, R.

    1984-01-01

    Development of a robot simulation program based on geometric transformation softwares available in most computer graphics systems and program features are described. The program can be extended to simulate robots coordinating with external devices (such as tools, fixtures, conveyors) using geometric transformations to describe the…

  1. Simulation of quantum computation : A deterministic event-based approach

    NARCIS (Netherlands)

    Michielsen, K; De Raedt, K; De Raedt, H

    We demonstrate that locally connected networks of machines that have primitive learning capabilities can be used to perform a deterministic, event-based simulation of quantum computation. We present simulation results for basic quantum operations such as the Hadamard and the controlled-NOT gate, and

  2. Simulation of Quantum Computation : A Deterministic Event-Based Approach

    NARCIS (Netherlands)

    Michielsen, K.; Raedt, K. De; Raedt, H. De

    2005-01-01

    We demonstrate that locally connected networks of machines that have primitive learning capabilities can be used to perform a deterministic, event-based simulation of quantum computation. We present simulation results for basic quantum operations such as the Hadamard and the controlled-NOT gate, and

  3. Computer simulation system of neural PID control on nuclear reactor

    International Nuclear Information System (INIS)

    Chen Yuzhong; Yang Kaijun; Shen Yongping

    2001-01-01

    Neural network proportional integral differential (PID) controller on nuclear reactor is designed, and the control process is simulated by computer. The simulation result show that neutral network PID controller can automatically adjust its parameter to ideal state, and good control result can be gotten in reactor control process

  4. Computer simulations of shear thickening of concentrated dispersions

    NARCIS (Netherlands)

    Boersma, W.H.; Laven, J.; Stein, H.N.

    1995-01-01

    Stokesian dynamics computer simulations were performed on monolayers of equally sized spheres. The influence of repulsive and attractive forces on the rheological behavior and on the microstructure were studied. Under specific conditions shear thickening could be observed in the simulations, usually

  5. Investigating the Effectiveness of Computer Simulations for Chemistry Learning

    Science.gov (United States)

    Plass, Jan L.; Milne, Catherine; Homer, Bruce D.; Schwartz, Ruth N.; Hayward, Elizabeth O.; Jordan, Trace; Verkuilen, Jay; Ng, Florrie; Wang, Yan; Barrientos, Juan

    2012-01-01

    Are well-designed computer simulations an effective tool to support student understanding of complex concepts in chemistry when integrated into high school science classrooms? We investigated scaling up the use of a sequence of simulations of kinetic molecular theory and associated topics of diffusion, gas laws, and phase change, which we designed…

  6. Computer simulations of long-time tails: what's new?

    NARCIS (Netherlands)

    Hoef, van der M.A.; Frenkel, D.

    1995-01-01

    Twenty five years ago Alder and Wainwright discovered, by simulation, the 'long-time tails' in the velocity autocorrelation function of a single particle in fluid [1]. Since then, few qualitatively new results on long-time tails have been obtained by computer simulations. However, within the

  7. Factors cost effectively improved using computer simulations of ...

    African Journals Online (AJOL)

    LPhidza

    effectively managed using computer simulations in semi-arid conditions pertinent to much of sub-Saharan Africa. ... small scale farmers to obtain optimal crop yields thus ensuring their food security and livelihood is ... those that simultaneously incorporate and simulate processes involved throughout the course of crop ...

  8. Plant Closings and Capital Flight: A Computer-Assisted Simulation.

    Science.gov (United States)

    Warner, Stanley; Breitbart, Myrna M.

    1989-01-01

    A course at Hampshire College was designed to simulate the decision-making environment in which constituencies in a medium-sized city would respond to the closing and relocation of a major corporate plant. The project, constructed as a role simulation with a computer component, is described. (MLW)

  9. Computational fluid dynamics simulations and validations of results

    CSIR Research Space (South Africa)

    Sitek, MA

    2013-09-01

    Full Text Available Wind flow influence on a high-rise building is analyzed. The research covers full-scale tests, wind-tunnel experiments and numerical simulations. In the present paper computational model used in simulations is described and the results, which were...

  10. Computer-Based Simulation Games in Public Administration Education

    Directory of Open Access Journals (Sweden)

    Kutergina Evgeniia

    2017-12-01

    Full Text Available Computer simulation, an active learning technique, is now one of the advanced pedagogical technologies. Th e use of simulation games in the educational process allows students to gain a firsthand understanding of the processes of real life. Public- administration, public-policy and political-science courses increasingly adopt simulation games in universities worldwide. Besides person-to-person simulation games, there are computer-based simulations in public-administration education. Currently in Russia the use of computer-based simulation games in Master of Public Administration (MPA curricula is quite limited. Th is paper focuses on computer- based simulation games for students of MPA programmes. Our aim was to analyze outcomes of implementing such games in MPA curricula. We have done so by (1 developing three computer-based simulation games about allocating public finances, (2 testing the games in the learning process, and (3 conducting a posttest examination to evaluate the effect of simulation games on students’ knowledge of municipal finances. Th is study was conducted in the National Research University Higher School of Economics (HSE and in the Russian Presidential Academy of National Economy and Public Administration (RANEPA during the period of September to December 2015, in Saint Petersburg, Russia. Two groups of students were randomly selected in each university and then randomly allocated either to the experimental or the control group. In control groups (n=12 in HSE, n=13 in RANEPA students had traditional lectures. In experimental groups (n=12 in HSE, n=13 in RANEPA students played three simulation games apart from traditional lectures. Th is exploratory research shows that the use of computer-based simulation games in MPA curricula can improve students’ outcomes by 38 %. In general, the experimental groups had better performances on the post-test examination (Figure 2. Students in the HSE experimental group had 27.5 % better

  11. Energy consumption during simulated minimal access surgery with and without using an armrest.

    Science.gov (United States)

    Jafri, Mansoor; Brown, Stuart; Arnold, Graham; Abboud, Rami; Wang, Weijie

    2013-03-01

    Minimal access surgery (MAS) can be a lengthy procedure when compared to open surgery and therefore surgeon fatigue becomes an important issue and surgeons may expose themselves to chronic injuries and making errors. There have been few studies on this topic and they have used only questionnaires and electromyography rather than direct measurement of energy expenditure (EE). The aim of this study was to investigate whether the use of an armrest could reduce the EE of surgeons during MAS. Sixteen surgeons performed simulated MAS with and without using an armrest. They were required to perform the time-consuming task of using scissors to cut a rubber glove through its top layer in a triangular fashion with the help of a laparoscopic camera. Energy consumptions were measured using the Oxycon Mobile system during all the procedures. Error rate and duration time for simulated surgery were recorded. After performing the simulated surgery, subjects scored how comfortable they felt using the armrest. It was found that O(2) uptake (VO(2)) was 5 % less when surgeons used the armrest. The error rate when performing the procedure with the armrest was 35 % compared with 42.29 % without the armrest. Additionally, comfort levels with the armrest were higher than without the armrest. 75 % of surgeons indicated a preference for using the armrest during the simulated surgery. The armrest provides support for surgeons and cuts energy consumption during simulated MAS.

  12. A computer assisted toolholder to guide surgery in stereotactic space.

    Science.gov (United States)

    Giorgi, C; Pluchino, F; Luzzara, M; Ongania, E; Casolino, D S

    1994-01-01

    A computer assisted toolholder, integrated with an anatomical graphic 3-D rendering programme, is presented. Stereotactic neuroanatomical images are acquired, and the same reference system is employed to represent the position of the toolholder on the monitor. The surgeon can check the orientation of different approach trajectories, moving the toolholder in a situation of virtual reality. Angular values expressed by high precision encoders on the five joints of the toolholder modify "on line" the representation of the configuration of the toolholder within the three dimensional representation of the patient's anatomy.

  13. Freeform fabrication of tissue-simulating phantom for potential use of surgical planning in conjoined twins separation surgery.

    Science.gov (United States)

    Shen, Shuwei; Wang, Haili; Xue, Yue; Yuan, Li; Zhou, Ximing; Zhao, Zuhua; Dong, Erbao; Liu, Bin; Liu, Wendong; Cromeens, Barrett; Adler, Brent; Besner, Gail; Xu, Ronald X

    2017-09-08

    Preoperative assessment of tissue anatomy and accurate surgical planning is crucial in conjoined twin separation surgery. We developed a new method that combines three-dimensional (3D) printing, assembling, and casting to produce anatomic models of high fidelity for surgical planning. The related anatomic features of the conjoined twins were captured by computed tomography (CT), classified as five organ groups, and reconstructed as five computer models. Among these organ groups, the skeleton was produced by fused deposition modeling (FDM) using acrylonitrile-butadiene-styrene. For the other four organ groups, shell molds were prepared by FDM and cast with silica gel to simulate soft tissues, with contrast enhancement pigments added to simulate different CT and visual contrasts. The produced models were assembled, positioned firmly within a 3D printed shell mold simulating the skin boundary, and cast with transparent silica gel. The produced phantom was subject to further CT scan in comparison with that of the patient data for fidelity evaluation. Further data analysis showed that the produced model reassembled the geometric features of the original CT data with an overall mean deviation of less than 2 mm, indicating the clinical potential to use this method for surgical planning in conjoined twin separation surgery.

  14. 76 FR 15321 - SEDASYS Computer-Assisted Personalized Sedation System; Ethicon Endo-Surgery, Inc.'s, Petition...

    Science.gov (United States)

    2011-03-21

    ...] SEDASYS Computer-Assisted Personalized Sedation System; Ethicon Endo-Surgery, Inc.'s, Petition for Review... an advisory committee Ethicon Endo- Surgery Inc.'s (EES's), petition for review of the Agency's... Foreman, FDA, CDRH, to Ken Charak, Ethicon Endo-Surgery, Inc., containing the order denying approval of...

  15. Computational fluid dynamics simulations of light water reactor flows

    International Nuclear Information System (INIS)

    Tzanos, C.P.; Weber, D.P.

    1999-01-01

    Advances in computational fluid dynamics (CFD), turbulence simulation, and parallel computing have made feasible the development of three-dimensional (3-D) single-phase and two-phase flow CFD codes that can simulate fluid flow and heat transfer in realistic reactor geometries with significantly reduced reliance, especially in single phase, on empirical correlations. The objective of this work was to assess the predictive power and computational efficiency of a CFD code in the analysis of a challenging single-phase light water reactor problem, as well as to identify areas where further improvements are needed

  16. Digital control computer upgrade at the Cernavoda NPP simulator

    International Nuclear Information System (INIS)

    Ionescu, T.

    2006-01-01

    The Plant Process Computer equips some Nuclear Power Plants, like CANDU-600, with Centralized Control performed by an assembly of two computers known as Digital Control Computers (DCC) and working in parallel for safely driving of the plan at steady state and during normal maneuvers but also during abnormal transients when the plant is automatically steered to a safe state. The Centralized Control means both hardware and software with obligatory presence in the frame of the Full Scope Simulator and subject to changing its configuration with specific requirements during the plant and simulator life and covered by this subsection

  17. A review of computer-based simulators for ultrasound training.

    Science.gov (United States)

    Blum, Tobias; Rieger, Andreas; Navab, Nassir; Friess, Helmut; Martignoni, Marc

    2013-04-01

    Computer-based simulators for ultrasound training are a topic of recent interest. During the last 15 years, many different systems and methods have been proposed. This article provides an overview and classification of systems in this domain and a discussion of their advantages. Systems are classified and discussed according to the image simulation method, user interactions and medical applications. Computer simulation of ultrasound has one key advantage over traditional training. It enables novel training concepts, for example, through advanced visualization, case databases, and automatically generated feedback. Qualitative evaluations have mainly shown positive learning effects. However, few quantitative evaluations have been performed and long-term effects have to be examined.

  18. Computer based training simulator for Hunterston Nuclear Power Station

    International Nuclear Information System (INIS)

    Bowden, R.S.M.; Hacking, D.

    1978-01-01

    For reasons which are stated, the Hunterston-B nuclear power station automatic control system includes a manual over-ride facility. It is therefore essential for the station engineers to be trained to recognise and control all feasible modes of plant and logic malfunction. A training simulator has been built which consists of a replica of the shutdown monitoring panel in the Central Control Room and is controlled by a mini-computer. This paper highlights the computer aspects of the simulator and relevant derived experience, under the following headings: engineering background; shutdown sequence equipment; simulator equipment; features; software; testing; maintenance. (U.K.)

  19. Validation and computing and performance studies for the ATLAS simulation

    CERN Document Server

    Marshall, Z; The ATLAS collaboration

    2009-01-01

    We present the validation of the ATLAS simulation software pro ject. Software development is controlled by nightly builds and several levels of automatic tests to ensure stability. Computing validation, including CPU time, memory, and disk space required per event, is benchmarked for all software releases. Several different physics processes and event types are checked to thoroughly test all aspects of the detector simulation. The robustness of the simulation software is demonstrated by the production of 500 million events on the World-wide LHC Computing Grid in the last year.

  20. Accurate computer simulation of a drift chamber

    International Nuclear Information System (INIS)

    Killian, T.J.

    1980-01-01

    A general purpose program for drift chamber studies is described. First the capacitance matrix is calculated using a Green's function technique. The matrix is used in a linear-least-squares fit to choose optimal operating voltages. Next the electric field is computed, and given knowledge of gas parameters and magnetic field environment, a family of electron trajectories is determined. These are finally used to make drift distance vs time curves which may be used directly by a track reconstruction program. Results are compared with data obtained from the cylindrical chamber in the Axial Field Magnet experiment at the CERN ISR

  1. Accurate computer simulation of a drift chamber

    CERN Document Server

    Killian, T J

    1980-01-01

    The author describes a general purpose program for drift chamber studies. First the capacitance matrix is calculated using a Green's function technique. The matrix is used in a linear-least-squares fit to choose optimal operating voltages. Next the electric field is computed, and given knowledge of gas parameters and magnetic field environment, a family of electron trajectories is determined. These are finally used to make drift distance vs time curves which may be used directly by a track reconstruction program. The results are compared with data obtained from the cylindrical chamber in the Axial Field Magnet experiment at the CERN ISR. (1 refs).

  2. Computer Models Simulate Fine Particle Dispersion

    Science.gov (United States)

    2010-01-01

    Through a NASA Seed Fund partnership with DEM Solutions Inc., of Lebanon, New Hampshire, scientists at Kennedy Space Center refined existing software to study the electrostatic phenomena of granular and bulk materials as they apply to planetary surfaces. The software, EDEM, allows users to import particles and obtain accurate representations of their shapes for modeling purposes, such as simulating bulk solids behavior, and was enhanced to be able to more accurately model fine, abrasive, cohesive particles. These new EDEM capabilities can be applied in many industries unrelated to space exploration and have been adopted by several prominent U.S. companies, including John Deere, Pfizer, and Procter & Gamble.

  3. Computer simulation and automation of data processing

    International Nuclear Information System (INIS)

    Tikhonov, A.N.

    1981-01-01

    The principles of computerized simulation and automation of data processing are presented. The automized processing system is constructed according to the module-hierarchical principle. The main operating conditions of the system are as follows: preprocessing, installation analysis, interpretation, accuracy analysis and controlling parameters. The definition of the quasireal experiment permitting to plan the real experiment is given. It is pointed out that realization of the quasireal experiment by means of the computerized installation model with subsequent automized processing permits to scan the quantitative aspect of the system as a whole as well as provides optimal designing of installation parameters for obtaining maximum resolution [ru

  4. Use of computer graphics simulation for teaching of flexible sigmoidoscopy.

    Science.gov (United States)

    Baillie, J; Jowell, P; Evangelou, H; Bickel, W; Cotton, P

    1991-05-01

    The concept of simulation training in endoscopy is now well-established. The systems currently under development employ either computer graphics simulation or interactive video technology; each has its strengths and weaknesses. A flexible sigmoidoscopy training device has been designed which uses graphic routines--such as object oriented programming and double buffering--in entirely new ways. These programming techniques compensate for the limitations of currently available desk-top microcomputers. By boosting existing computer 'horsepower' with next generation coprocessors and sophisticated graphics tools such as intensity interpolation (Gouraud shading), the realism of computer simulation of flexible sigmoidoscopy is being greatly enhanced. The computer program has teaching and scoring capabilities, making it a truly interactive system. Use has been made of this ability to record, grade and store each trainee encounter in computer memory as part of a multi-center, prospective trial of simulation training being conducted currently in the USA. A new input device, a dummy endoscope, has been designed that allows application of variable resistance to the insertion tube. This greatly enhances tactile feedback, such as resistance during looping. If carefully designed trials show that computer simulation is an attractive and effective training tool, it is expected that this technology will evolve rapidly and be made widely available to trainee endoscopists.

  5. Stochastic Computer Simulation of Cermet Coatings Formation

    Directory of Open Access Journals (Sweden)

    Oleg P. Solonenko

    2015-01-01

    Full Text Available An approach to the modeling of the process of the formation of thermal coatings lamellar structure, including plasma coatings, at the spraying of cermet powders is proposed. The approach based on the theoretical fundamentals developed which could be used for rapid and sufficiently accurate prediction of thickness and diameter of cermet splats as well as temperature at interface “flattening quasi-liquid cermet particle-substrate” depending on the key physical parameters (KPPs: temperature, velocity and size of particle, substrate temperature, and concentration of finely dispersed solid inclusions uniformly distributed in liquid metal binder. The results are presented, which concern the development of the computational algorithm and the program complex for modeling the process of laying the splats in the coating with regard to the topology of its surface, which varies dynamically at the spraying, as well as the formation of lamellar structure and porosity of the coating. The results of numerical experiments are presented through the example of thermal spraying the cermet TiC-30 vol.% NiCr powder, illustrating the performance of the developed computational technology.

  6. Molecular dynamics simulations and applications in computational toxicology and nanotoxicology.

    Science.gov (United States)

    Selvaraj, Chandrabose; Sakkiah, Sugunadevi; Tong, Weida; Hong, Huixiao

    2018-02-01

    Nanotoxicology studies toxicity of nanomaterials and has been widely applied in biomedical researches to explore toxicity of various biological systems. Investigating biological systems through in vivo and in vitro methods is expensive and time taking. Therefore, computational toxicology, a multi-discipline field that utilizes computational power and algorithms to examine toxicology of biological systems, has gained attractions to scientists. Molecular dynamics (MD) simulations of biomolecules such as proteins and DNA are popular for understanding of interactions between biological systems and chemicals in computational toxicology. In this paper, we review MD simulation methods, protocol for running MD simulations and their applications in studies of toxicity and nanotechnology. We also briefly summarize some popular software tools for execution of MD simulations. Published by Elsevier Ltd.

  7. Computational methods for coupling microstructural and micromechanical materials response simulations

    Energy Technology Data Exchange (ETDEWEB)

    HOLM,ELIZABETH A.; BATTAILE,CORBETT C.; BUCHHEIT,THOMAS E.; FANG,HUEI ELIOT; RINTOUL,MARK DANIEL; VEDULA,VENKATA R.; GLASS,S. JILL; KNOROVSKY,GERALD A.; NEILSEN,MICHAEL K.; WELLMAN,GERALD W.; SULSKY,DEBORAH; SHEN,YU-LIN; SCHREYER,H. BUCK

    2000-04-01

    Computational materials simulations have traditionally focused on individual phenomena: grain growth, crack propagation, plastic flow, etc. However, real materials behavior results from a complex interplay between phenomena. In this project, the authors explored methods for coupling mesoscale simulations of microstructural evolution and micromechanical response. In one case, massively parallel (MP) simulations for grain evolution and microcracking in alumina stronglink materials were dynamically coupled. In the other, codes for domain coarsening and plastic deformation in CuSi braze alloys were iteratively linked. this program provided the first comparison of two promising ways to integrate mesoscale computer codes. Coupled microstructural/micromechanical codes were applied to experimentally observed microstructures for the first time. In addition to the coupled codes, this project developed a suite of new computational capabilities (PARGRAIN, GLAD, OOF, MPM, polycrystal plasticity, front tracking). The problem of plasticity length scale in continuum calculations was recognized and a solution strategy was developed. The simulations were experimentally validated on stockpile materials.

  8. Positive Wigner functions render classical simulation of quantum computation efficient.

    Science.gov (United States)

    Mari, A; Eisert, J

    2012-12-07

    We show that quantum circuits where the initial state and all the following quantum operations can be represented by positive Wigner functions can be classically efficiently simulated. This is true both for continuous-variable as well as discrete variable systems in odd prime dimensions, two cases which will be treated on entirely the same footing. Noting the fact that Clifford and Gaussian operations preserve the positivity of the Wigner function, our result generalizes the Gottesman-Knill theorem. Our algorithm provides a way of sampling from the output distribution of a computation or a simulation, including the efficient sampling from an approximate output distribution in the case of sampling imperfections for initial states, gates, or measurements. In this sense, this work highlights the role of the positive Wigner function as separating classically efficiently simulable systems from those that are potentially universal for quantum computing and simulation, and it emphasizes the role of negativity of the Wigner function as a computational resource.

  9. CUBESIM, Hypercube and Denelcor Hep Parallel Computer Simulation

    International Nuclear Information System (INIS)

    Dunigan, T.H.

    1988-01-01

    1 - Description of program or function: CUBESIM is a set of subroutine libraries and programs for the simulation of message-passing parallel computers and shared-memory parallel computers. Subroutines are supplied to simulate the Intel hypercube and the Denelcor HEP parallel computers. The system permits a user to develop and test parallel programs written in C or FORTRAN on a single processor. The user may alter such hypercube parameters as message startup times, packet size, and the computation-to-communication ratio. The simulation generates a trace file that can be used for debugging, performance analysis, or graphical display. 2 - Method of solution: The CUBESIM simulator is linked with the user's parallel application routines to run as a single UNIX process. The simulator library provides a small operating system to perform process and message management. 3 - Restrictions on the complexity of the problem: Up to 128 processors can be simulated with a virtual memory limit of 6 million bytes. Up to 1000 processes can be simulated

  10. Virtual reality-based simulators for spine surgery: a systematic review.

    Science.gov (United States)

    Pfandler, Michael; Lazarovici, Marc; Stefan, Philipp; Wucherer, Patrick; Weigl, Matthias

    2017-09-01

    Virtual reality (VR)-based simulators offer numerous benefits and are very useful in assessing and training surgical skills. Virtual reality-based simulators are standard in some surgical subspecialties, but their actual use in spinal surgery remains unclear. Currently, only technical reviews of VR-based simulators are available for spinal surgery. Thus, we performed a systematic review that examined the existing research on VR-based simulators in spinal procedures. We also assessed the quality of current studies evaluating VR-based training in spinal surgery. Moreover, we wanted to provide a guide for future studies evaluating VR-based simulators in this field. This is a systematic review of the current scientific literature regarding VR-based simulation in spinal surgery. Five data sources were systematically searched to identify relevant peer-reviewed articles regarding virtual, mixed, or augmented reality-based simulators in spinal surgery. A qualitative data synthesis was performed with particular attention to evaluation approaches and outcomes. Additionally, all included studies were appraised for their quality using the Medical Education Research Study Quality Instrument (MERSQI) tool. The initial review identified 476 abstracts and 63 full texts were then assessed by two reviewers. Finally, 19 studies that examined simulators for the following procedures were selected: pedicle screw placement, vertebroplasty, posterior cervical laminectomy and foraminotomy, lumbar puncture, facet joint injection, and spinal needle insertion and placement. These studies had a low-to-medium methodological quality with a MERSQI mean score of 11.47 out of 18 (standard deviation=1.81). This review described the current state and applications of VR-based simulator training and assessment approaches in spinal procedures. Limitations, strengths, and future advancements of VR-based simulators for training and assessment in spinal surgery were explored. Higher-quality studies with

  11. Computer simulations of high pressure systems

    International Nuclear Information System (INIS)

    Wilkins, M.L.

    1977-01-01

    Numerical methods are capable of solving very difficult problems in solid mechanics and gas dynamics. In the design of engineering structures, critical decisions are possible if the behavior of materials is correctly described in the calculation. Problems of current interest require accurate analysis of stress-strain fields that range from very small elastic displacement to very large plastic deformation. A finite difference program is described that solves problems over this range and in two and three space-dimensions and time. A series of experiments and calculations serve to establish confidence in the plasticity formulation. The program can be used to design high pressure systems where plastic flow occurs. The purpose is to identify material properties, strength and elongation, that meet the operating requirements. An objective is to be able to perform destructive testing on a computer rather than on the engineering structure. Examples of topical interest are given

  12. Computational Simulations and the Scientific Method

    Science.gov (United States)

    Kleb, Bil; Wood, Bill

    2005-01-01

    As scientific simulation software becomes more complicated, the scientific-software implementor's need for component tests from new model developers becomes more crucial. The community's ability to follow the basic premise of the Scientific Method requires independently repeatable experiments, and model innovators are in the best position to create these test fixtures. Scientific software developers also need to quickly judge the value of the new model, i.e., its cost-to-benefit ratio in terms of gains provided by the new model and implementation risks such as cost, time, and quality. This paper asks two questions. The first is whether other scientific software developers would find published component tests useful, and the second is whether model innovators think publishing test fixtures is a feasible approach.

  13. Computer simulations of dendrimer-polyelectrolyte complexes.

    Science.gov (United States)

    Pandav, Gunja; Ganesan, Venkat

    2014-08-28

    We carry out a systematic analysis of static properties of the clusters formed by complexation between charged dendrimers and linear polyelectrolyte (LPE) chains in a dilute solution under good solvent conditions. We use single chain in mean-field simulations and analyze the structure of the clusters through radial distribution functions of the dendrimer, cluster size, and charge distributions. The effects of LPE length, charge ratio between LPE and dendrimer, the influence of salt concentration, and the dendrimer generation number are examined. Systems with short LPEs showed a reduced propensity for aggregation with dendrimers, leading to formation of smaller clusters. In contrast, larger dendrimers and longer LPEs lead to larger clusters with significant bridging. Increasing salt concentration was seen to reduce aggregation between dendrimers as a result of screening of electrostatic interactions. Generally, maximum complexation was observed in systems with an equal amount of net dendrimer and LPE charges, whereas either excess LPE or dendrimer concentrations resulted in reduced clustering between dendrimers.

  14. A computer code to simulate X-ray imaging techniques

    International Nuclear Information System (INIS)

    Duvauchelle, Philippe; Freud, Nicolas; Kaftandjian, Valerie; Babot, Daniel

    2000-01-01

    A computer code was developed to simulate the operation of radiographic, radioscopic or tomographic devices. The simulation is based on ray-tracing techniques and on the X-ray attenuation law. The use of computer-aided drawing (CAD) models enables simulations to be carried out with complex three-dimensional (3D) objects and the geometry of every component of the imaging chain, from the source to the detector, can be defined. Geometric unsharpness, for example, can be easily taken into account, even in complex configurations. Automatic translations or rotations of the object can be performed to simulate radioscopic or tomographic image acquisition. Simulations can be carried out with monochromatic or polychromatic beam spectra. This feature enables, for example, the beam hardening phenomenon to be dealt with or dual energy imaging techniques to be studied. The simulation principle is completely deterministic and consequently the computed images present no photon noise. Nevertheless, the variance of the signal associated with each pixel of the detector can be determined, which enables contrast-to-noise ratio (CNR) maps to be computed, in order to predict quantitatively the detectability of defects in the inspected object. The CNR is a relevant indicator for optimizing the experimental parameters. This paper provides several examples of simulated images that illustrate some of the rich possibilities offered by our software. Depending on the simulation type, the computation time order of magnitude can vary from 0.1 s (simple radiographic projection) up to several hours (3D tomography) on a PC, with a 400 MHz microprocessor. Our simulation tool proves to be useful in developing new specific applications, in choosing the most suitable components when designing a new testing chain, and in saving time by reducing the number of experimental tests

  15. A computer code to simulate X-ray imaging techniques

    Energy Technology Data Exchange (ETDEWEB)

    Duvauchelle, Philippe E-mail: philippe.duvauchelle@insa-lyon.fr; Freud, Nicolas; Kaftandjian, Valerie; Babot, Daniel

    2000-09-01

    A computer code was developed to simulate the operation of radiographic, radioscopic or tomographic devices. The simulation is based on ray-tracing techniques and on the X-ray attenuation law. The use of computer-aided drawing (CAD) models enables simulations to be carried out with complex three-dimensional (3D) objects and the geometry of every component of the imaging chain, from the source to the detector, can be defined. Geometric unsharpness, for example, can be easily taken into account, even in complex configurations. Automatic translations or rotations of the object can be performed to simulate radioscopic or tomographic image acquisition. Simulations can be carried out with monochromatic or polychromatic beam spectra. This feature enables, for example, the beam hardening phenomenon to be dealt with or dual energy imaging techniques to be studied. The simulation principle is completely deterministic and consequently the computed images present no photon noise. Nevertheless, the variance of the signal associated with each pixel of the detector can be determined, which enables contrast-to-noise ratio (CNR) maps to be computed, in order to predict quantitatively the detectability of defects in the inspected object. The CNR is a relevant indicator for optimizing the experimental parameters. This paper provides several examples of simulated images that illustrate some of the rich possibilities offered by our software. Depending on the simulation type, the computation time order of magnitude can vary from 0.1 s (simple radiographic projection) up to several hours (3D tomography) on a PC, with a 400 MHz microprocessor. Our simulation tool proves to be useful in developing new specific applications, in choosing the most suitable components when designing a new testing chain, and in saving time by reducing the number of experimental tests.

  16. An introduction to computer simulation methods applications to physical systems

    CERN Document Server

    Gould, Harvey; Christian, Wolfgang

    2007-01-01

    Now in its third edition, this book teaches physical concepts using computer simulations. The text incorporates object-oriented programming techniques and encourages readers to develop good programming habits in the context of doing physics. Designed for readers at all levels , An Introduction to Computer Simulation Methods uses Java, currently the most popular programming language. Introduction, Tools for Doing Simulations, Simulating Particle Motion, Oscillatory Systems, Few-Body Problems: The Motion of the Planets, The Chaotic Motion of Dynamical Systems, Random Processes, The Dynamics of Many Particle Systems, Normal Modes and Waves, Electrodynamics, Numerical and Monte Carlo Methods, Percolation, Fractals and Kinetic Growth Models, Complex Systems, Monte Carlo Simulations of Thermal Systems, Quantum Systems, Visualization and Rigid Body Dynamics, Seeing in Special and General Relativity, Epilogue: The Unity of Physics For all readers interested in developing programming habits in the context of doing phy...

  17. The Simulation and Analysis of the Closed Die Hot Forging Process by A Computer Simulation Method

    Directory of Open Access Journals (Sweden)

    Dipakkumar Gohil

    2012-06-01

    Full Text Available The objective of this research work is to study the variation of various parameters such as stress, strain, temperature, force, etc. during the closed die hot forging process. A computer simulation modeling approach has been adopted to transform the theoretical aspects in to a computer algorithm which would be used to simulate and analyze the closed die hot forging process. For the purpose of process study, the entire deformation process has been divided in to finite number of steps appropriately and then the output values have been computed at each deformation step. The results of simulation have been graphically represented and suitable corrective measures are also recommended, if the simulation results do not agree with the theoretical values. This computer simulation approach would significantly improve the productivity and reduce the energy consumption of the overall process for the components which are manufactured by the closed die forging process and contribute towards the efforts in reducing the global warming.

  18. Computer simulation as an operational and training aid

    International Nuclear Information System (INIS)

    Lee, D.J.; Tottman-Trayner, E.

    1995-01-01

    The paper describes how the rapid development of desktop computing power, the associated fall in prices, and the advancement of computer graphics technology driven by the entertainment industry has enabled the nuclear industry to achieve improvements in operation and training through the use of computer simulation. Applications are focused on the fuel handling operations at Torness Power Station where visualization through computer modelling is being used to enhance operator awareness and to assist in a number of operational scenarios. It is concluded that there are significant benefits to be gained from the introduction of the facility at Torness as well as other locations. (author)

  19. A computer-simulated liver phantom (virtual liver phantom) for multidetector computed tomography evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Funama, Yoshinori [Kumamoto University, Department of Radiological Sciences, School of Health Sciences, Kumamoto (Japan); Awai, Kazuo; Nakayama, Yoshiharu; Liu, Da; Yamashita, Yasuyuki [Kumamoto University, Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto (Japan); Miyazaki, Osamu; Goto, Taiga [Hitachi Medical Corporation, Tokyo (Japan); Hori, Shinichi [Gate Tower Institute of Image Guided Therapy, Osaka (Japan)

    2006-04-15

    The purpose of study was to develop a computer-simulated liver phantom for hepatic CT studies. A computer-simulated liver phantom was mathematically constructed on a computer workstation. The computer-simulated phantom was calibrated using real CT images acquired by an actual four-detector CT. We added an inhomogeneous texture to the simulated liver by referring to CT images of chronically damaged human livers. The mean CT number of the simulated liver was 60 HU and we added numerous 5-to 10-mm structures with 60{+-}10 HU/mm. To mimic liver tumors we added nodules measuring 8, 10, and 12 mm in diameter with CT numbers of 60{+-}10, 60{+-}15, and 60{+-}20 HU. Five radiologists visually evaluated similarity of the texture of the computer-simulated liver phantom and a real human liver to confirm the appropriateness of the virtual liver images using a five-point scale. The total score was 44 in two radiologists, and 42, 41, and 39 in one radiologist each. They evaluated that the textures of virtual liver were comparable to those of human liver. Our computer-simulated liver phantom is a promising tool for the evaluation of the image quality and diagnostic performance of hepatic CT imaging. (orig.)

  20. Investigations into radiation damages of reactor materials by computer simulation

    International Nuclear Information System (INIS)

    Bronnikov, V.A.

    2004-01-01

    Data on the state of works in European countries in the field of computerized simulation of radiation damages of reactor materials under the context of the international projects ITEM (European Database for Multiscale Modelling) and SIRENA (Simulation of Radiation Effects in Zr-Nb alloys) - computerized simulation of stress corrosion when contact of Zr-Nb alloys with iodine are presented. Computer codes for the simulation of radiation effects in reactor materials were developed. European Database for Multiscale Modelling (EDAM) was organized using the results of the investigations provided in the ITEM project [ru

  1. The role of computer-aided 3D surgery and stereolithographic modelling for vector orientation in premaxillary and trans-sinusoidal maxillary distraction osteogenesis.

    Science.gov (United States)

    Varol, Altan; Basa, Selçuk

    2009-06-01

    Maxillary distraction osteogenesis is a challenging procedure when it is performed with internal submerged distractors due to obligation of setting accurate distraction vectors. Five patients with severe maxillary retrognathy were planned with Mimics 10.01 CMF and Simplant 10.01 software. Distraction vectors and rods of distractors were arranged in 3D environment and on STL models. All patients were operated under general anaesthesia and complete Le Fort I downfracture was performed. All distractions were performed according to orientated vectors. All patients achieved stable occlusion and satisfactory aesthetic outcome at the end of the treatment period. Preoperative bending of internal maxillary distractors prevents significant loss of operation time. 3D computer-aided surgical simulation and model surgery provide accurate orientation of distraction vectors for premaxillary and internal trans-sinusoidal maxillary distraction. Combination of virtual surgical simulation and stereolithographic models surgery can be validated as an effective method of preoperative planning for complicated maxillofacial surgery cases.

  2. Computer simulation of sensitization in stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Logan, R W

    1983-12-20

    Stainless steel containers are prime candidates for the containment of nuclear waste in tuff rock. The thermal history of a container involves exposure to temperatures of 500 to 600/sup 0/C when it is welded and possibly filled with molten waste glass, followed by hundreds of years exposure in the 100 to 300/sup 0/C range. The problems of short- and long-term sensitization in stainless steels have been addressed by two computer programs. The TTS program uses classical nucleation and growth theory plus experimental input to predict the onset of precipitation or sensitization under complex thermal histories. The FEMGB program uses quadratic finite-element methods to analyze diffusion processes and chromium depletion during precipitate growth. The results of studies using both programs indicate that sensitization should not be a problem in any of the austenitic stainless steels considered. However, more precise information on the process thermal cycles, especially during welding of the container, is needed. Contributions from dislocation pipe diffusion could promote long-term low-temperature sensitization.

  3. Noise simulation in cone beam CT imaging with parallel computing

    International Nuclear Information System (INIS)

    Tu, S.-J.; Shaw, Chris C; Chen, Lingyun

    2006-01-01

    We developed a computer noise simulation model for cone beam computed tomography imaging using a general purpose PC cluster. This model uses a mono-energetic x-ray approximation and allows us to investigate three primary performance components, specifically quantum noise, detector blurring and additive system noise. A parallel random number generator based on the Weyl sequence was implemented in the noise simulation and a visualization technique was accordingly developed to validate the quality of the parallel random number generator. In our computer simulation model, three-dimensional (3D) phantoms were mathematically modelled and used to create 450 analytical projections, which were then sampled into digital image data. Quantum noise was simulated and added to the analytical projection image data, which were then filtered to incorporate flat panel detector blurring. Additive system noise was generated and added to form the final projection images. The Feldkamp algorithm was implemented and used to reconstruct the 3D images of the phantoms. A 24 dual-Xeon PC cluster was used to compute the projections and reconstructed images in parallel with each CPU processing 10 projection views for a total of 450 views. Based on this computer simulation system, simulated cone beam CT images were generated for various phantoms and technique settings. Noise power spectra for the flat panel x-ray detector and reconstructed images were then computed to characterize the noise properties. As an example among the potential applications of our noise simulation model, we showed that images of low contrast objects can be produced and used for image quality evaluation

  4. Coupling Computer-Aided Process Simulation and ...

    Science.gov (United States)

    A methodology is described for developing a gate-to-gate life cycle inventory (LCI) of a chemical manufacturing process to support the application of life cycle assessment in the design and regulation of sustainable chemicals. The inventories were derived by first applying process design and simulation of develop a process flow diagram describing the energy and basic material flows of the system. Additional techniques developed by the U.S. Environmental Protection Agency for estimating uncontrolled emissions from chemical processing equipment were then applied to obtain a detailed emission profile for the process. Finally, land use for the process was estimated using a simple sizing model. The methodology was applied to a case study of acetic acid production based on the Cativa tm process. The results reveal improvements in the qualitative LCI for acetic acid production compared to commonly used databases and top-down methodologies. The modeling techniques improve the quantitative LCI results for inputs and uncontrolled emissions. With provisions for applying appropriate emission controls, the proposed method can provide an estimate of the LCI that can be used for subsequent life cycle assessments. As part of its mission, the Agency is tasked with overseeing the use of chemicals in commerce. This can include consideration of a chemical's potential impact on health and safety, resource conservation, clean air and climate change, clean water, and sustainable

  5. Computer simulation of LMFBR piping systems

    International Nuclear Information System (INIS)

    A-Moneim, M.T.; Chang, Y.W.; Fistedis, S.H.

    1977-01-01

    Integrity of piping systems is one of the main concerns of the safety issues of Liquid Metal Fast Breeder Reactors (LMFBR). Hypothetical core disruptive accidents (HCDA) and water-sodium interaction are two examples of sources of high pressure pulses that endanger the integrity of the heat transport piping systems of LMFBRs. Although plastic wall deformation attenuates pressure peaks so that only pressures slightly higher than the pipe yield pressure propagate along the system, the interaction of these pulses with the different components of the system, such as elbows, valves, heat exchangers, etc.; and with one another produce a complex system of pressure pulses that cause more plastic deformation and perhaps damage to components. A generalized piping component and a tee branching model are described. An optional tube bundle and interior rigid wall simulation model makes such a generalized component model suited for modelling of valves, reducers, expansions, and heat exchangers. The generalized component and the tee branching junction models are combined with the pipe-elbow loop model so that a more general piping system can be analyzed both hydrodynamically and structurally under the effect of simultaneous pressure pulses

  6. Predictive Toxicology and Computer Simulation of Male ...

    Science.gov (United States)

    The reproductive tract is a complex, integrated organ system with diverse embryology and unique sensitivity to prenatal environmental exposures that disrupt morphoregulatory processes and endocrine signaling. U.S. EPA’s in vitro high-throughput screening (HTS) database (ToxCastDB) was used to profile the bioactivity of 54 chemicals with male developmental consequences across ~800 molecular and cellular features. The in vitro bioactivity on molecular targets could be condensed into 156 gene annotations in a bipartite network. These results highlighted the role of estrogen and androgen signaling pathways in male reproductive tract development, and importantly, broadened the list of molecular targets to include GPCRs, cytochrome-P450s, vascular remodeling proteins, and retinoic acid signaling. A multicellular agent-based model was used to simulate the complex interactions between morphoregulatory, endocrine, and environmental influences during genital tubercle (GT) development. Spatially dynamic signals (e.g., SHH, FGF10, and androgen) were implemented in the model to address differential adhesion, cell motility, proliferation, and apoptosis. Under control of androgen signaling, urethral tube closure was an emergent feature of the model that was linked to gender-specific rates of ventral mesenchymal proliferation and urethral plate endodermal apoptosis. A systemic parameter sweep was used to examine the sensitivity of crosstalk between genetic deficiency and envi

  7. Associative Memory computing power and its simulation.

    CERN Document Server

    Volpi, G; The ATLAS collaboration

    2014-01-01

    The associative memory (AM) chip is ASIC device specifically designed to perform ``pattern matching'' at very high speed and with parallel access to memory locations. The most extensive use for such device will be the ATLAS Fast Tracker (FTK) processor, where more than 8000 chips will be installed in 128 VME boards, specifically designed for high throughput in order to exploit the chip's features. Each AM chip will store a database of about 130000 pre-calculated patterns, allowing FTK to use about 1 billion patterns for the whole system, with any data inquiry broadcast to all memory elements simultaneously within the same clock cycle (10 ns), thus data retrieval time is independent of the database size. Speed and size of the system are crucial for real-time High Energy Physics applications, such as the ATLAS FTK processor. Using 80 million channels of the ATLAS tracker, FTK finds tracks within 100 $\\mathrm{\\mu s}$. The simulation of such a parallelized system is an extremely complex task when executed in comm...

  8. [Guided and computer-assisted implant surgery and prosthetic: The continuous digital workflow].

    Science.gov (United States)

    Pascual, D; Vaysse, J

    2016-02-01

    New continuous digital workflow protocols of guided and computer-assisted implant surgery improve accuracy of implant positioning. The design of the future prosthesis is based on the available prosthetic space, gingival height and occlusal relationship with the opposing and adjacent teeth. The implant position and length depend on volume, density and bone quality, gingival height, tooth-implant and implant-implant distances, implant parallelism, axis and type of the future prosthesis. The crown modeled on the software will therefore serve as a guide to the future implant axis and not the reverse. The guide is made by 3D printing. The software determines surgical protocol with the drilling sequences. The unitary or plural prosthesis, modeled on the software and built before surgery, is loaded directly after implant placing, if needed. These protocols allow for a full continuity of the digital workflow. The software provides the surgeon and the dental technician a total freedom for the prosthetic-surgery guide design and the position of the implants. The prosthetic project, occlusal and aesthetic, taking the bony and surgical constraints into account, is optimized. The implant surgery is simplified and becomes less "stressful" for the patient and the surgeon. Guided and computer-assisted surgery with continuous digital workflow is becoming the technique of choice to improve the accuracy and quality of implant rehabilitation. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  9. Using EDUCache Simulator for the Computer Architecture and Organization Course

    Directory of Open Access Journals (Sweden)

    Sasko Ristov

    2013-07-01

    Full Text Available The computer architecture and organization course is essential in all computer science and engineering programs, and the most selected and liked elective course for related engineering disciplines. However, the attractiveness brings a new challenge, it requires a lot of effort by the instructor, to explain rather complicated concepts to beginners or to those who study related disciplines. The usage of visual simulators can improve both the teaching and learning processes. The overall goal is twofold: 1~to enable a visual environment to explain the basic concepts and 2~to increase the student's willingness and ability to learn the material.A lot of visual simulators have been used for the computer architecture and organization course. However, due to the lack of visual simulators for simulation of the cache memory concepts, we have developed a new visual simulator EDUCache simulator. In this paper we present that it can be effectively and efficiently used as a supporting tool in the learning process of modern multi-layer, multi-cache and multi-core multi-processors.EDUCache's features enable an environment for performance evaluation and engineering of software systems, i.e. the students will also understand the importance of computer architecture building parts and hopefully, will increase their curiosity for hardware courses in general.

  10. Application of advanced virtual reality and 3D computer assisted technologies in tele-3D-computer assisted surgery in rhinology.

    Science.gov (United States)

    Klapan, Ivica; Vranjes, Zeljko; Prgomet, Drago; Lukinović, Juraj

    2008-03-01

    The real-time requirement means that the simulation should be able to follow the actions of the user that may be moving in the virtual environment. The computer system should also store in its memory a three-dimensional (3D) model of the virtual environment. In that case a real-time virtual reality system will update the 3D graphic visualization as the user moves, so that up-to-date visualization is always shown on the computer screen. Upon completion of the tele-operation, the surgeon compares the preoperative and postoperative images and models of the operative field, and studies video records of the procedure itself Using intraoperative records, animated images of the real tele-procedure performed can be designed. Virtual surgery offers the possibility of preoperative planning in rhinology. The intraoperative use of computer in real time requires development of appropriate hardware and software to connect medical instrumentarium with the computer and to operate the computer by thus connected instrumentarium and sophisticated multimedia interfaces.

  11. Surgeon Training in Telerobotic Surgery via a Hardware-in-the-Loop Simulator

    Directory of Open Access Journals (Sweden)

    Xiao Li

    2017-01-01

    Full Text Available This work presents a software and hardware framework for a telerobotic surgery safety and motor skill training simulator. The aims are at providing trainees a comprehensive simulator for acquiring essential skills to perform telerobotic surgery. Existing commercial robotic surgery simulators lack features for safety training and optimal motion planning, which are critical factors in ensuring patient safety and efficiency in operation. In this work, we propose a hardware-in-the-loop simulator directly introducing these two features. The proposed simulator is built upon the Raven-II™ open source surgical robot, integrated with a physics engine and a safety hazard injection engine. Also, a Fast Marching Tree-based motion planning algorithm is used to help trainee learn the optimal instrument motion patterns. The main contributions of this work are (1 reproducing safety hazards events, related to da Vinci™ system, reported to the FDA MAUDE database, with a novel haptic feedback strategy to provide feedback to the operator when the underlying dynamics differ from the real robot’s states so that the operator will be aware and can mitigate the negative impact of the safety-critical events, and (2 using motion planner to generate semioptimal path in an interactive robotic surgery training environment.

  12. SiMon: Simulation Monitor for Computational Astrophysics

    Science.gov (United States)

    Xuran Qian, Penny; Cai, Maxwell Xu; Portegies Zwart, Simon; Zhu, Ming

    2017-09-01

    Scientific discovery via numerical simulations is important in modern astrophysics. This relatively new branch of astrophysics has become possible due to the development of reliable numerical algorithms and the high performance of modern computing technologies. These enable the analysis of large collections of observational data and the acquisition of new data via simulations at unprecedented accuracy and resolution. Ideally, simulations run until they reach some pre-determined termination condition, but often other factors cause extensive numerical approaches to break down at an earlier stage. In those cases, processes tend to be interrupted due to unexpected events in the software or the hardware. In those cases, the scientist handles the interrupt manually, which is time-consuming and prone to errors. We present the Simulation Monitor (SiMon) to automatize the farming of large and extensive simulation processes. Our method is light-weight, it fully automates the entire workflow management, operates concurrently across multiple platforms and can be installed in user space. Inspired by the process of crop farming, we perceive each simulation as a crop in the field and running simulation becomes analogous to growing crops. With the development of SiMon we relax the technical aspects of simulation management. The initial package was developed for extensive parameter searchers in numerical simulations, but it turns out to work equally well for automating the computational processing and reduction of observational data reduction.

  13. Use of computer-based clinical examination to assess medical students in surgery.

    Science.gov (United States)

    El Shallaly, Gamal E H A; Mekki, Abdelrahman M

    2012-01-01

    To improve the viewing of the video-projected structured clinical examination (ViPSCE), we developed a computerized version; the computer-based clinical examination (CCE). This was used to assess medical students' higher knowledge and problem solving skills in surgery. We present how we did this, test score descriptive statistics, and the students' evaluation of the CCE. A CCE in surgery was administered to assess a class of 43 final year medical students at the end of their surgical clerkship. Like the ViPSCE, the exam was delivered as a slide show, using a PowerPoint computer program. However, instead of projecting it onto a screen, each student used a computer. There were 20 slides containing either still photos or short video clips of clinical situations in surgery. The students answered by hand writing on the exam papers. At the end, they completed evaluation forms. The exam papers were corrected manually. Test score descriptive statistics were calculated and correlated with the students' scores in other exams in surgery. Administration of the CCE was straightforward. The test scores were normally distributed (mean = median = 4.9). They correlated significantly with the total scores obtained by the students in surgery (r = 0.68), and with each of the other exam modalities in surgery, such as the multiple choice and structured essay questions. Acceptability of the CCE to the students was high and they recommended the use of the CCE in other departments. CCE is feasible and popular with students. It inherits the validity and reliability of the ViPSCE with the added advantage of improving the viewing of the slides.

  14. Computer-based endoscopic image-processing technology for endourology and laparoscopic surgery

    International Nuclear Information System (INIS)

    Igarashi, Tatsuo; Suzuki, Hiroyoshi; Naya, Yukio

    2009-01-01

    Endourology and laparoscopic surgery are evolving in accordance with developments in instrumentation and progress in surgical technique. Recent advances in computer and image-processing technology have enabled novel images to be created from conventional endoscopic and laparoscopic video images. Such technology harbors the potential to advance endourology and laparoscopic surgery by adding new value and function to the endoscope. The panoramic and three-dimensional images created by computer processing are two outstanding features that can address the shortcomings of conventional endoscopy and laparoscopy, such as narrow field of view, lack of depth cue, and discontinuous information. The wide panoramic images show an anatomical map' of the abdominal cavity and hollow organs with high brightness and resolution, as the images are collected from video images taken in a close-up manner. To assist in laparoscopic surgery, especially in suturing, a three-dimensional movie can be obtained by enhancing movement parallax using a conventional monocular laparoscope. In tubular organs such as the prostatic urethra, reconstruction of three-dimensional structure can be achieved, implying the possibility of a liquid dynamic model for assessing local urethral resistance in urination. Computer-based processing of endoscopic images will establish new tools for endourology and laparoscopic surgery in the near future. (author)

  15. VIRGY: a virtual reality and force feedback based endoscopic surgery simulator.

    Science.gov (United States)

    Baur, C; Guzzoni, D; Georg, O

    1998-01-01

    This paper describes the VIRGY project at the VRAI Group (Virtual Reality and Active Interface), Swiss Federal Institute of Technology (Lausanne, Switzerland). Since 1994, we have been investigating a variety of virtual-reality based methods for simulating laparoscopic surgery procedures. Our goal is to develop an endoscopic surgical training tool which realistically simulates the interactions between one or more surgical instruments and gastrointestinal organs. To support real-time interaction and manipulation between instruments and organs, we have developed several novel graphic simulation techniques. In particular, we are using live video texturing to achieve dynamic effects such as bleeding or vaporization of fatty tissues. Special texture manipulations allows us to generate pulsing objects while minimizing processor load. Additionally, we have created a new surface deformation algorithm which enables real-time deformations under external constraints. Lastly, we have developed a new 3D object definition which allows us to perform operations such as total or partial object cuttings, as well as to selectively render objects with different levels of detail. To provide realistic physical simulation of the forces and torques on surgical instruments encountered during an operation, we have also designed a new haptic device dedicated to endososcopic surgery constraints. We are using special interpolation and extrapolation techniques to integrate our 25 Hz visual simulation with the 300 Hz feedback required for realistic tactile interaction. The fully VIRGY simulator has been tested by surgeons and the quality of both our visual and haptic simulation has been judged sufficient for training basic surgery gestures.

  16. Using virtual reality simulation to assess competence in video-assisted thoracoscopic surgery (VATS) lobectomy

    DEFF Research Database (Denmark)

    Jensen, Katrine; Bjerrum, Flemming; Hansen, Henrik Jessen

    2017-01-01

    for a virtual reality simulator test of a video-assisted thoracoscopic surgery (VATS) lobectomy of a right upper lobe. METHODS: Participants with varying experience in VATS lobectomy were included. They were familiarized with a virtual reality simulator (LapSim(®)) and introduced to the steps of the procedure...... % false positives) and failed four of the experienced surgeons (29 % false negatives). CONCLUSION: This study is the first to establish validity evidence for a VATS right upper lobe lobectomy virtual reality simulator test. Several simulator metrics demonstrated significant differences between novices...

  17. Large scale particle simulations in a virtual memory computer

    International Nuclear Information System (INIS)

    Gray, P.C.; Million, R.; Wagner, J.S.; Tajima, T.

    1983-01-01

    Virtual memory computers are capable of executing large-scale particle simulations even when the memory requirements exceeds the computer core size. The required address space is automatically mapped onto slow disc memory the the operating system. When the simulation size is very large, frequent random accesses to slow memory occur during the charge accumulation and particle pushing processes. Assesses to slow memory significantly reduce the excecution rate of the simulation. We demonstrate in this paper that with the proper choice of sorting algorithm, a nominal amount of sorting to keep physically adjacent particles near particles with neighboring array indices can reduce random access to slow memory, increase the efficiency of the I/O system, and hence, reduce the required computing time. (orig.)

  18. Surgical resource utilization in urban terrorist bombing: a computer simulation.

    Science.gov (United States)

    Hirshberg, A; Stein, M; Walden, R

    1999-09-01

    The objective of this study was to analyze the utilization of surgical staff and facilities during an urban terrorist bombing incident. A discrete-event computer model of the emergency room and related hospital facilities was constructed and implemented, based on cumulated data from 12 urban terrorist bombing incidents in Israel. The simulation predicts that the admitting capacity of the hospital depends primarily on the number of available surgeons and defines an optimal staff profile for surgeons, residents, and trauma nurses. The major bottlenecks in the flow of critical casualties are the shock rooms and the computed tomographic scanner but not the operating rooms. The simulation also defines the number of reinforcement staff needed to treat noncritical casualties and shows that radiology is the major obstacle to the flow of these patients. Computer simulation is an important new tool for the optimization of surgical service elements for a multiple-casualty situation.

  19. Computer simulation of a 3-phase induction motor

    International Nuclear Information System (INIS)

    Memon, N.A.; Unsworth, P.J.

    2004-01-01

    Computer Simulation of a 3-phase squirrel-cage induction motor is presented in Microsoft QBASIC for understanding trends and various operational modes of an induction motor. Thyristor fed, phase controlled induction motor (three-wire) model has been simulated. In which voltage is applied to the motor stator winding through back-to-back connected thyristors as controlled switches in series with the stator. The simulated induction motor system opens up towards a wide range of investigation/analysis options for research and development work in the field. Key features of the simulation performed are highlighted for development of better understanding of the work done. Complete study of an Induction Motor, starting modes in terms the voltage/current, torque/speed characteristics and their graphical representation produced is presented. Ideal agreement of the simulation results with the notional outcome encourages users to go ahead for various hardware development projects based on the study through the simulation. (author)

  20. Advanced Simulation and Computing FY17 Implementation Plan, Version 0

    Energy Technology Data Exchange (ETDEWEB)

    McCoy, Michel [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Archer, Bill [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hendrickson, Bruce [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Wade, Doug [National Nuclear Security Administration (NNSA), Washington, DC (United States). Office of Advanced Simulation and Computing and Institutional Research and Development; Hoang, Thuc [National Nuclear Security Administration (NNSA), Washington, DC (United States). Computational Systems and Software Environment

    2016-08-29

    The Stockpile Stewardship Program (SSP) is an integrated technical program for maintaining the safety, surety, and reliability of the U.S. nuclear stockpile. The SSP uses nuclear test data, computational modeling and simulation, and experimental facilities to advance understanding of nuclear weapons. It includes stockpile surveillance, experimental research, development and engineering programs, and an appropriately scaled production capability to support stockpile requirements. This integrated national program requires the continued use of experimental facilities and programs, and the computational capabilities to support these programs. The Advanced Simulation and Computing Program (ASC) is a cornerstone of the SSP, providing simulation capabilities and computational resources that support annual stockpile assessment and certification, study advanced nuclear weapons design and manufacturing processes, analyze accident scenarios and weapons aging, and provide the tools to enable stockpile Life Extension Programs (LEPs) and the resolution of Significant Finding Investigations (SFIs). This requires a balance of resource, including technical staff, hardware, simulation software, and computer science solutions. ASC is now focused on increasing predictive capabilities in a three-dimensional (3D) simulation environment while maintaining support to the SSP. The program continues to improve its unique tools for solving progressively more difficult stockpile problems (sufficient resolution, dimensionality, and scientific details), and quantifying critical margins and uncertainties. Resolving each issue requires increasingly difficult analyses because the aging process has progressively moved the stockpile further away from the original test base. Where possible, the program also enables the use of high performance computing (HPC) and simulation tools to address broader national security needs, such as foreign nuclear weapon assessments and counter nuclear terrorism.

  1. Computer simulations for thorium doped tungsten crystals

    Energy Technology Data Exchange (ETDEWEB)

    Eberhard, Bernd

    2009-07-17

    set of Langevin equations, i.e. stochastic differential equations including properly chosen ''noise'' terms. A new integration scheme is derived for integrating the equations of motion, which closely resembles the well-known Velocity Verlet algorithm. As a first application of the EAM potentials, we calculate the phonon dispersion for tungsten and thorium. Furthermore, the potentials are used to derive the excess volumes of point defects, i.e. for vacancies and Th-impurities in tungsten, grain boundary structures and energies. Additionally, we take a closer look at various stacking fault energies and link the results to the potential splitting of screw dislocations in tungsten into partials. We also compare the energetic stability of screw, edge and mixed-type dislocations. Besides this, we are interested in free enthalpy differences, for which we make use of the Overlapping Distribution Method (ODM), an efficient, albeit computationally demanding, method to calculate free enthalpy differences, with which we address the question of lattice formation, vacancy formation and impurity formation at varying temperatures. (orig.)

  2. Computer simulations for thorium doped tungsten crystals

    International Nuclear Information System (INIS)

    Eberhard, Bernd

    2009-01-01

    differential equations including properly chosen ''noise'' terms. A new integration scheme is derived for integrating the equations of motion, which closely resembles the well-known Velocity Verlet algorithm. As a first application of the EAM potentials, we calculate the phonon dispersion for tungsten and thorium. Furthermore, the potentials are used to derive the excess volumes of point defects, i.e. for vacancies and Th-impurities in tungsten, grain boundary structures and energies. Additionally, we take a closer look at various stacking fault energies and link the results to the potential splitting of screw dislocations in tungsten into partials. We also compare the energetic stability of screw, edge and mixed-type dislocations. Besides this, we are interested in free enthalpy differences, for which we make use of the Overlapping Distribution Method (ODM), an efficient, albeit computationally demanding, method to calculate free enthalpy differences, with which we address the question of lattice formation, vacancy formation and impurity formation at varying temperatures. (orig.)

  3. High performance stream computing for particle beam transport simulations

    International Nuclear Information System (INIS)

    Appleby, R; Bailey, D; Higham, J; Salt, M

    2008-01-01

    Understanding modern particle accelerators requires simulating charged particle transport through the machine elements. These simulations can be very time consuming due to the large number of particles and the need to consider many turns of a circular machine. Stream computing offers an attractive way to dramatically improve the performance of such simulations by calculating the simultaneous transport of many particles using dedicated hardware. Modern Graphics Processing Units (GPUs) are powerful and affordable stream computing devices. The results of simulations of particle transport through the booster-to-storage-ring transfer line of the DIAMOND synchrotron light source using an NVidia GeForce 7900 GPU are compared to the standard transport code MAD. It is found that particle transport calculations are suitable for stream processing and large performance increases are possible. The accuracy and potential speed gains are compared and the prospects for future work in the area are discussed

  4. Computer simulation of variform fuel assemblies using Dragon code

    International Nuclear Information System (INIS)

    Ju Haitao; Wu Hongchun; Yao Dong

    2005-01-01

    The DRAGON is a cell code that developed for the CANDU reactor by the Ecole Polytechnique de Montreal of CANADA. Although, the DRAGON is mainly used to simulate the CANDU super-cell fuel assembly, it has an ability to simulate other geometries of the fuel assembly. However, only NEACRP benchmark problem of the BWR lattice cell was analyzed until now except for the CANDU reactor. We also need to develop the code to simulate the variform fuel assemblies, especially, for design of the advanced reactor. We validated that the cell code DRAGON is useful for simulating various kinds of the fuel assembly by analyzing the rod-shape fuel assembly of the PWR and the MTR plate-shape fuel assembly. Some other kinds of geometry of geometry were computed. Computational results show that the DRAGON is able to analyze variform fuel assembly problems and the precision is high. (authors)

  5. Computer simulations and the changing face of scientific experimentation

    CERN Document Server

    Duran, Juan M

    2013-01-01

    Computer simulations have become a central tool for scientific practice. Their use has replaced, in many cases, standard experimental procedures. This goes without mentioning cases where the target system is empirical but there are no techniques for direct manipulation of the system, such as astronomical observation. To these cases, computer simulations have proved to be of central importance. The question about their use and implementation, therefore, is not only a technical one but represents a challenge for the humanities as well. In this volume, scientists, historians, and philosophers joi

  6. Environments for online maritime simulators with cloud computing capabilities

    Science.gov (United States)

    Raicu, Gabriel; Raicu, Alexandra

    2016-12-01

    This paper presents the cloud computing environments, network principles and methods for graphical development in realistic naval simulation, naval robotics and virtual interactions. The aim of this approach is to achieve a good simulation quality in large networked environments using open source solutions designed for educational purposes. Realistic rendering of maritime environments requires near real-time frameworks with enhanced computing capabilities during distance interactions. E-Navigation concepts coupled with the last achievements in virtual and augmented reality will enhance the overall experience leading to new developments and innovations. We have to deal with a multiprocessing situation using advanced technologies and distributed applications using remote ship scenario and automation of ship operations.

  7. A computer code package for electron transport Monte Carlo simulation

    International Nuclear Information System (INIS)

    Popescu, Lucretiu M.

    1999-01-01

    A computer code package was developed for solving various electron transport problems by Monte Carlo simulation. It is based on condensed history Monte Carlo algorithm. In order to get reliable results over wide ranges of electron energies and target atomic numbers, specific techniques of electron transport were implemented such as: Moliere multiscatter angular distributions, Blunck-Leisegang multiscatter energy distribution, sampling of electron-electron and Bremsstrahlung individual interactions. Path-length and lateral displacement corrections algorithms and the module for computing collision, radiative and total restricted stopping powers and ranges of electrons are also included. Comparisons of simulation results with experimental measurements are finally presented. (author)

  8. Computational simulation in architectural and environmental acoustics methods and applications of wave-based computation

    CERN Document Server

    Sakamoto, Shinichi; Otsuru, Toru

    2014-01-01

    This book reviews a variety of methods for wave-based acoustic simulation and recent applications to architectural and environmental acoustic problems. Following an introduction providing an overview of computational simulation of sound environment, the book is in two parts: four chapters on methods and four chapters on applications. The first part explains the fundamentals and advanced techniques for three popular methods, namely, the finite-difference time-domain method, the finite element method, and the boundary element method, as well as alternative time-domain methods. The second part demonstrates various applications to room acoustics simulation, noise propagation simulation, acoustic property simulation for building components, and auralization. This book is a valuable reference that covers the state of the art in computational simulation for architectural and environmental acoustics.  

  9. Comprehensive Simulation Lifecycle Management for High Performance Computing Modeling and Simulation, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — There are significant logistical barriers to entry-level high performance computing (HPC) modeling and simulation (M IllinoisRocstar) sets up the infrastructure for...

  10. Scalable space-time adaptive simulation tools for computational electrocardiology

    OpenAIRE

    Krause, Dorian; Krause, Rolf

    2013-01-01

    This work is concerned with the development of computational tools for the solution of reaction-diffusion equations from the field of computational electrocardiology. We designed lightweight spatially and space-time adaptive schemes for large-scale parallel simulations. We propose two different adaptive schemes based on locally structured meshes, managed either via a conforming coarse tessellation or a forest of shallow trees. A crucial ingredient of our approach is a non-conforming morta...

  11. Computer simulation of ion recombination in irradiated nonpolar liquids

    International Nuclear Information System (INIS)

    Bartczak, W.M.; Hummel, A.

    1986-01-01

    A review on the results of computer simulation of the diffusion controlled recombination of ions is presented. The ions generated in clusters of two and three pairs of oppositely charged ions were considered. The recombination kinetics and the ion escape probability at infinite time with and without external electric field were computed. These results are compared with the calculations based on the single-pair theory. (athor)

  12. SHIPBUILDING PRODUCTION PROCESS DESIGN METHODOLOGY USING COMPUTER SIMULATION

    OpenAIRE

    Marko Hadjina; Nikša Fafandjel; Tin Matulja

    2015-01-01

    In this research a shipbuilding production process design methodology, using computer simulation, is suggested. It is expected from suggested methodology to give better and more efficient tool for complex shipbuilding production processes design procedure. Within the first part of this research existing practice for production process design in shipbuilding was discussed, its shortcomings and problem were emphasized. In continuing, discrete event simulation modelling method, as basis of sugge...

  13. Cloud Computing in Science and Engineering and the “SciShop.ru” Computer Simulation Center

    Directory of Open Access Journals (Sweden)

    E. V. Vorozhtsov

    2011-12-01

    Full Text Available Various aspects of cloud computing applications for scientific research, applied design, and remote education are described in this paper. An analysis of the different aspects is performed based on the experience from the “SciShop.ru” Computer Simulation Center. This analysis shows that cloud computing technology has wide prospects in scientific research applications, applied developments and also remote education of specialists, postgraduates, and students.

  14. A Computer Simulation of Community Pharmacy Practice for Educational Use.

    Science.gov (United States)

    Bindoff, Ivan; Ling, Tristan; Bereznicki, Luke; Westbury, Juanita; Chalmers, Leanne; Peterson, Gregory; Ollington, Robert

    2014-11-15

    To provide a computer-based learning method for pharmacy practice that is as effective as paper-based scenarios, but more engaging and less labor-intensive. We developed a flexible and customizable computer simulation of community pharmacy. Using it, the students would be able to work through scenarios which encapsulate the entirety of a patient presentation. We compared the traditional paper-based teaching method to our computer-based approach using equivalent scenarios. The paper-based group had 2 tutors while the computer group had none. Both groups were given a prescenario and postscenario clinical knowledge quiz and survey. Students in the computer-based group had generally greater improvements in their clinical knowledge score, and third-year students using the computer-based method also showed more improvements in history taking and counseling competencies. Third-year students also found the simulation fun and engaging. Our simulation of community pharmacy provided an educational experience as effective as the paper-based alternative, despite the lack of a human tutor.

  15. Digital Workflow for Computer-Guided Implant Surgery in Edentulous Patients: A Case Report.

    Science.gov (United States)

    Oh, Ji-Hyeon; An, Xueyin; Jeong, Seung-Mi; Choi, Byung-Ho

    2017-12-01

    The purpose of this article was to describe a fully digital workflow used to perform computer-guided flapless implant placement in an edentulous patient without the use of conventional impressions, models, or a radiographic guide. Digital data for the workflow were acquired using an intraoral scanner and cone-beam computed tomography (CBCT). The image fusion of the intraoral scan data and CBCT data was performed by matching resin markers placed in the patient's mouth. The definitive digital data were used to design a prosthetically driven implant position, surgical template, and computer-aided design and computer-aided manufacturing fabricated fixed dental prosthesis. The authors believe this is the first published case describing such a technique in computer-guided flapless implant surgery for edentulous patients. Copyright © 2017 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  16. Computer simulation studies in condensed-matter physics 5. Proceedings

    International Nuclear Information System (INIS)

    Landau, D.P.; Mon, K.K.; Schuettler, H.B.

    1993-01-01

    As the role of computer simulations began to increase in importance, we sensed a need for a ''meeting place'' for both experienced simulators and neophytes to discuss new techniques and results in an environment which promotes extended discussion. As a consequence of these concerns, The Center for Simulational Physics established an annual workshop on Recent Developments in Computer Simulation Studies in Condensed-Matter Physics. This year's workshop was the fifth in this series and the interest which the scientific community has shown demonstrates quite clearly the useful purpose which the series has served. The workshop was held at the University of Georgia, February 17-21, 1992, and these proceedings from a record of the workshop which is published with the goal of timely dissemination of the papers to a wider audience. The proceedings are divided into four parts. The first part contains invited papers which deal with simulational studies of classical systems and includes an introduction to some new simulation techniques and special purpose computers as well. A separate section of the proceedings is devoted to invited papers on quantum systems including new results for strongly correlated electron and quantum spin models. The third section is comprised of a single, invited description of a newly developed software shell designed for running parallel programs. The contributed presentations comprise the final chapter. (orig.). 79 figs

  17. Large Atmospheric Computation on the Earth Simulator: The LACES Project

    Directory of Open Access Journals (Sweden)

    Michel Desgagné

    2006-01-01

    Full Text Available The Large Atmospheric Computation on the Earth Simulator (LACES project is a joint initiative between Canadian and Japanese meteorological services and academic institutions that focuses on the high resolution simulation of Hurricane Earl (1998. The unique aspect of this effort is the extent of the computational domain, which covers all of North America and Europe with a grid spacing of 1 km. The Canadian Mesoscale Compressible Community (MC2 model is shown to parallelize effectively on the Japanese Earth Simulator (ES supercomputer; however, even using the extensive computing resources of the ES Center (ESC, the full simulation for the majority of Hurricane Earl's lifecycle takes over eight days to perform and produces over 5.2 TB of raw data. Preliminary diagnostics show that the results of the LACES simulation for the tropical stage of Hurricane Earl's lifecycle compare well with available observations for the storm. Further studies involving advanced diagnostics have commenced, taking advantage of the uniquely large spatial extent of the high resolution LACES simulation to investigate multiscale interactions in the hurricane and its environment. It is hoped that these studies will enhance our understanding of processes occurring within the hurricane and between the hurricane and its planetary-scale environment.

  18. A compositional reservoir simulator on distributed memory parallel computers

    International Nuclear Information System (INIS)

    Rame, M.; Delshad, M.

    1995-01-01

    This paper presents the application of distributed memory parallel computes to field scale reservoir simulations using a parallel version of UTCHEM, The University of Texas Chemical Flooding Simulator. The model is a general purpose highly vectorized chemical compositional simulator that can simulate a wide range of displacement processes at both field and laboratory scales. The original simulator was modified to run on both distributed memory parallel machines (Intel iPSC/960 and Delta, Connection Machine 5, Kendall Square 1 and 2, and CRAY T3D) and a cluster of workstations. A domain decomposition approach has been taken towards parallelization of the code. A portion of the discrete reservoir model is assigned to each processor by a set-up routine that attempts a data layout as even as possible from the load-balance standpoint. Each of these subdomains is extended so that data can be shared between adjacent processors for stencil computation. The added routines that make parallel execution possible are written in a modular fashion that makes the porting to new parallel platforms straight forward. Results of the distributed memory computing performance of Parallel simulator are presented for field scale applications such as tracer flood and polymer flood. A comparison of the wall-clock times for same problems on a vector supercomputer is also presented

  19. Multiaxial mechanical properties and constitutive modeling of human adipose tissue: a basis for preoperative simulations in plastic and reconstructive surgery.

    Science.gov (United States)

    Sommer, Gerhard; Eder, Maximilian; Kovacs, Laszlo; Pathak, Heramb; Bonitz, Lars; Mueller, Christoph; Regitnig, Peter; Holzapfel, Gerhard A

    2013-11-01

    A preoperative simulation of soft tissue deformations during plastic and reconstructive surgery is desirable to support the surgeon's planning and to improve surgical outcomes. The current development of constitutive adipose tissue models, for the implementation in multilayer computational frameworks for the simulation of human soft tissue deformations, has proved difficult because knowledge of the required mechanical parameters of fat tissue is limited. Therefore, for the first time, human abdominal adipose tissues were mechanically investigated by biaxial tensile and triaxial shear tests. The results of this study suggest that human abdominal adipose tissues under quasi-static and dynamic multiaxial loadings can be characterized as a nonlinear, anisotropic and viscoelastic soft biological material. The nonlinear and anisotropic features are consequences of the material's collagenous microstructure. The aligned collagenous septa observed in histological investigations causes the anisotropy of the tissue. A hyperelastic model used in this study was appropriate to represent the quasi-static multiaxial mechanical behavior of fat tissue. The constitutive parameters are intended to serve as a basis for soft tissue simulations using the finite element method, which is an apparent method for obtaining promising results in the field of plastic and reconstructive surgery. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  20. The advanced computational testing and simulation toolkit (ACTS)

    International Nuclear Information System (INIS)

    Drummond, L.A.; Marques, O.

    2002-01-01

    During the past decades there has been a continuous growth in the number of physical and societal problems that have been successfully studied and solved by means of computational modeling and simulation. Distinctively, a number of these are important scientific problems ranging in scale from the atomic to the cosmic. For example, ionization is a phenomenon as ubiquitous in modern society as the glow of fluorescent lights and the etching on silicon computer chips; but it was not until 1999 that researchers finally achieved a complete numerical solution to the simplest example of ionization, the collision of a hydrogen atom with an electron. On the opposite scale, cosmologists have long wondered whether the expansion of the Universe, which began with the Big Bang, would ever reverse itself, ending the Universe in a Big Crunch. In 2000, analysis of new measurements of the cosmic microwave background radiation showed that the geometry of the Universe is flat, and thus the Universe will continue expanding forever. Both of these discoveries depended on high performance computer simulations that utilized computational tools included in the Advanced Computational Testing and Simulation (ACTS) Toolkit. The ACTS Toolkit is an umbrella project that brought together a number of general purpose computational tool development projects funded and supported by the U.S. Department of Energy (DOE). These tools, which have been developed independently, mainly at DOE laboratories, make it easier for scientific code developers to write high performance applications for parallel computers. They tackle a number of computational issues that are common to a large number of scientific applications, mainly implementation of numerical algorithms, and support for code development, execution and optimization. The ACTS Toolkit Project enables the use of these tools by a much wider community of computational scientists, and promotes code portability, reusability, reduction of duplicate efforts

  1. The advanced computational testing and simulation toolkit (ACTS)

    Energy Technology Data Exchange (ETDEWEB)

    Drummond, L.A.; Marques, O.

    2002-05-21

    During the past decades there has been a continuous growth in the number of physical and societal problems that have been successfully studied and solved by means of computational modeling and simulation. Distinctively, a number of these are important scientific problems ranging in scale from the atomic to the cosmic. For example, ionization is a phenomenon as ubiquitous in modern society as the glow of fluorescent lights and the etching on silicon computer chips; but it was not until 1999 that researchers finally achieved a complete numerical solution to the simplest example of ionization, the collision of a hydrogen atom with an electron. On the opposite scale, cosmologists have long wondered whether the expansion of the Universe, which began with the Big Bang, would ever reverse itself, ending the Universe in a Big Crunch. In 2000, analysis of new measurements of the cosmic microwave background radiation showed that the geometry of the Universe is flat, and thus the Universe will continue expanding forever. Both of these discoveries depended on high performance computer simulations that utilized computational tools included in the Advanced Computational Testing and Simulation (ACTS) Toolkit. The ACTS Toolkit is an umbrella project that brought together a number of general purpose computational tool development projects funded and supported by the U.S. Department of Energy (DOE). These tools, which have been developed independently, mainly at DOE laboratories, make it easier for scientific code developers to write high performance applications for parallel computers. They tackle a number of computational issues that are common to a large number of scientific applications, mainly implementation of numerical algorithms, and support for code development, execution and optimization. The ACTS Toolkit Project enables the use of these tools by a much wider community of computational scientists, and promotes code portability, reusability, reduction of duplicate efforts

  2. Using computer simulations to facilitate conceptual understanding of electromagnetic induction

    Science.gov (United States)

    Lee, Yu-Fen

    This study investigated the use of computer simulations to facilitate conceptual understanding in physics. The use of computer simulations in the present study was grounded in a conceptual framework drawn from findings related to the use of computer simulations in physics education. To achieve the goal of effective utilization of computers for physics education, I first reviewed studies pertaining to computer simulations in physics education categorized by three different learning frameworks and studies comparing the effects of different simulation environments. My intent was to identify the learning context and factors for successful use of computer simulations in past studies and to learn from the studies which did not obtain a significant result. Based on the analysis of reviewed literature, I proposed effective approaches to integrate computer simulations in physics education. These approaches are consistent with well established education principles such as those suggested by How People Learn (Bransford, Brown, Cocking, Donovan, & Pellegrino, 2000). The research based approaches to integrated computer simulations in physics education form a learning framework called Concept Learning with Computer Simulations (CLCS) in the current study. The second component of this study was to examine the CLCS learning framework empirically. The participants were recruited from a public high school in Beijing, China. All participating students were randomly assigned to two groups, the experimental (CLCS) group and the control (TRAD) group. Research based computer simulations developed by the physics education research group at University of Colorado at Boulder were used to tackle common conceptual difficulties in learning electromagnetic induction. While interacting with computer simulations, CLCS students were asked to answer reflective questions designed to stimulate qualitative reasoning and explanation. After receiving model reasoning online, students were asked to submit

  3. Parallelized computation for computer simulation of electrocardiograms using personal computers with multi-core CPU and general-purpose GPU.

    Science.gov (United States)

    Shen, Wenfeng; Wei, Daming; Xu, Weimin; Zhu, Xin; Yuan, Shizhong

    2010-10-01

    Biological computations like electrocardiological modelling and simulation usually require high-performance computing environments. This paper introduces an implementation of parallel computation for computer simulation of electrocardiograms (ECGs) in a personal computer environment with an Intel CPU of Core (TM) 2 Quad Q6600 and a GPU of Geforce 8800GT, with software support by OpenMP and CUDA. It was tested in three parallelization device setups: (a) a four-core CPU without a general-purpose GPU, (b) a general-purpose GPU plus 1 core of CPU, and (c) a four-core CPU plus a general-purpose GPU. To effectively take advantage of a multi-core CPU and a general-purpose GPU, an algorithm based on load-prediction dynamic scheduling was developed and applied to setting (c). In the simulation with 1600 time steps, the speedup of the parallel computation as compared to the serial computation was 3.9 in setting (a), 16.8 in setting (b), and 20.0 in setting (c). This study demonstrates that a current PC with a multi-core CPU and a general-purpose GPU provides a good environment for parallel computations in biological modelling and simulation studies. Copyright 2010 Elsevier Ireland Ltd. All rights reserved.

  4. Dynamic computer simulation of the Fort St. Vrain steam turbines

    International Nuclear Information System (INIS)

    Conklin, J.C.

    1983-01-01

    A computer simulation is described for the dynamic response of the Fort St. Vrain nuclear reactor regenerative intermediate- and low-pressure steam turbines. The fundamental computer-modeling assumptions for the turbines and feedwater heaters are developed. A turbine heat balance specifying steam and feedwater conditions at a given generator load and the volumes of the feedwater heaters are all that are necessary as descriptive input parameters. Actual plant data for a generator load reduction from 100 to 50% power (which occurred as part of a plant transient on November 9, 1981) are compared with computer-generated predictions, with reasonably good agreement

  5. An introduction to statistical computing a simulation-based approach

    CERN Document Server

    Voss, Jochen

    2014-01-01

    A comprehensive introduction to sampling-based methods in statistical computing The use of computers in mathematics and statistics has opened up a wide range of techniques for studying otherwise intractable problems.  Sampling-based simulation techniques are now an invaluable tool for exploring statistical models.  This book gives a comprehensive introduction to the exciting area of sampling-based methods. An Introduction to Statistical Computing introduces the classical topics of random number generation and Monte Carlo methods.  It also includes some advanced met

  6. Technology computer aided design simulation for VLSI MOSFET

    CERN Document Server

    Sarkar, Chandan Kumar

    2013-01-01

    Responding to recent developments and a growing VLSI circuit manufacturing market, Technology Computer Aided Design: Simulation for VLSI MOSFET examines advanced MOSFET processes and devices through TCAD numerical simulations. The book provides a balanced summary of TCAD and MOSFET basic concepts, equations, physics, and new technologies related to TCAD and MOSFET. A firm grasp of these concepts allows for the design of better models, thus streamlining the design process, saving time and money. This book places emphasis on the importance of modeling and simulations of VLSI MOS transistors and

  7. Computer simulations of the mechanical properties of metals

    DEFF Research Database (Denmark)

    Schiøtz, Jakob; Vegge, Tejs

    1999-01-01

    Atomic-scale computer simulations can be used to gain a better understanding of the mechanical properties of materials. In this paper we demonstrate how this can be done in the case of nanocrystalline copper, and give a brief overview of how simulations may be extended to larger length scales....... Nanocrystline metals are metals with grain sizes in the nanometre range, they have a number of technologically interesting properties such as much increased hardness and yield strength. Our simulations show that the deformation mechanisms are different in these materials than in coarse-grained materials...

  8. Computer simulation of gain fluctuations in proportional counters

    International Nuclear Information System (INIS)

    Demir, Nelgun; Tapan, . Ilhan

    2004-01-01

    A computer simulation code has been developed in order to examine the fluctuation in gas amplification in wire proportional counters which are common in detector applications in particle physics experiments. The magnitude of the variance in the gain dominates the statistical portion of the energy resolution. In order to compare simulation and experimental results, the gain and its variation has been calculated numerically for the well known Aleph Inner Tracking Detector geometry. The results show that the bias voltage has a strong influence on the variance in the gain. The simulation calculations are in good agreement with experimental results. (authors)

  9. A new possibility in thoracoscopic virtual reality simulation training: development and testing of a novel virtual reality simulator for video-assisted thoracoscopic surgery lobectomy.

    Science.gov (United States)

    Jensen, Katrine; Bjerrum, Flemming; Hansen, Henrik Jessen; Petersen, René Horsleben; Pedersen, Jesper Holst; Konge, Lars

    2015-10-01

    The aims of this study were to develop virtual reality simulation software for video-assisted thoracic surgery (VATS) lobectomy, to explore the opinions of thoracic surgeons concerning the VATS lobectomy simulator and to test the validity of the simulator metrics. Experienced VATS surgeons worked with computer specialists to develop a VATS lobectomy software for a virtual reality simulator. Thoracic surgeons with different degrees of experience in VATS were enrolled at the 22nd meeting of the European Society of Thoracic Surgeons (ESTS) held in Copenhagen in June 2014. The surgeons were divided according to the number of performed VATS lobectomies: novices (0 VATS lobectomies), intermediates (1-49 VATS lobectomies) and experienced (>50 VATS lobectomies). The participants all performed a lobectomy of a right upper lobe on the simulator and answered a questionnaire regarding content validity. Metrics were compared between the three groups. We succeeded in developing the first version of a virtual reality VATS lobectomy simulator. A total of 103 thoracic surgeons completed the simulated lobectomy and were distributed as follows: novices n = 32, intermediates n = 45 and experienced n = 26. All groups rated the overall user realism of the VATS lobectomy scenario to a median of 5 on a scale 1-7, with 7 being the best score. The experienced surgeons found the graphics and movements realistic and rated the scenario high in terms of usefulness as a training tool for novice and intermediate experienced thoracic surgeons, but not very useful as a training tool for experienced surgeons. The metric scores were not statistically significant between groups. This is the first study to describe a commercially available virtual reality simulator for a VATS lobectomy. More than 100 thoracic surgeons found the simulator realistic, and hence it showed good content validity. However, none of the built-in simulator metrics could significantly distinguish between novice, intermediate

  10. Computer simulation as representation of knowledge in education

    International Nuclear Information System (INIS)

    Krekic, Valerija Pinter; Namestovski, Zolt

    2009-01-01

    According to Aebli's operative method (1963) and Bruner's (1974) theory of representation the development of the process of thinking in teaching has the following phases - levels of abstraction: manipulation with specific things (specific phase), iconic representation (figural phase), symbolic representation (symbolic phase). Modern information technology has contributed to the enrichment of teaching and learning processes, especially in the fields of natural sciences and mathematics and those of production and technology. Simulation appears as a new possibility in the representation of knowledge. According to Guetzkow (1972) simulation is an operative representation of reality from a relevant aspect. It is about a model of an objective system, which is dynamic in itself. If that model is material it is a simple simulation, if it is abstract it is a reflective experiment, that is a computer simulation. This present work deals with the systematization and classification of simulation methods in the teaching of natural sciences and mathematics and of production and technology with special retrospective view on computer simulations and exemplar representation of the place and the role of this modern method of cognition. Key words: Representation of knowledge, modeling, simulation, education

  11. Computer Assisted Surgery and Current Trends in Orthopaedics Research and Total Joint Replacements

    Science.gov (United States)

    Amirouche, Farid

    2008-06-01

    Musculoskeletal research has brought about revolutionary changes in our ability to perform high precision surgery in joint replacement procedures. Recent advances in computer assisted surgery as well better materials have lead to reduced wear and greatly enhanced the quality of life of patients. The new surgical techniques to reduce the size of the incision and damage to underlying structures have been the primary advance toward this goal. These new techniques are known as MIS or Minimally Invasive Surgery. Total hip and knee Arthoplasties are at all time high reaching 1.2 million surgeries per year in the USA. Primary joint failures are usually due to osteoarthristis, rheumatoid arthritis, osteocronis and other inflammatory arthritis conditions. The methods for THR and TKA are critical to initial stability and longevity of the prostheses. This research aims at understanding the fundamental mechanics of the joint Arthoplasty and providing an insight into current challenges in patient specific fitting, fixing, and stability. Both experimental and analytical work will be presented. We will examine Cementless total hip arthroplasty success in the last 10 years and how computer assisted navigation is playing in the follow up studies. Cementless total hip arthroplasty attains permanent fixation by the ingrowth of bone into a porous coated surface. Loosening of an ingrown total hip arthroplasty occurs as a result of osteolysis of the periprosthetic bone and degradation of the bone prosthetic interface. The osteolytic process occurs as a result of polyethylene wear particles produced by the metal polyethylene articulation of the prosthesis. The total hip arthroplasty is a congruent joint and the submicron wear particles produced are phagocytized by macrophages initiating an inflammatory cascade. This cascade produces cytokines ultimately implicated in osteolysis. Resulting bone loss both on the acetabular and femoral sides eventually leads to component instability. As

  12. An Introduction to Parallel Cluster Computing Using PVM for Computer Modeling and Simulation of Engineering Problems

    International Nuclear Information System (INIS)

    Spencer, VN

    2001-01-01

    An investigation has been conducted regarding the ability of clustered personal computers to improve the performance of executing software simulations for solving engineering problems. The power and utility of personal computers continues to grow exponentially through advances in computing capabilities such as newer microprocessors, advances in microchip technologies, electronic packaging, and cost effective gigabyte-size hard drive capacity. Many engineering problems require significant computing power. Therefore, the computation has to be done by high-performance computer systems that cost millions of dollars and need gigabytes of memory to complete the task. Alternately, it is feasible to provide adequate computing in the form of clustered personal computers. This method cuts the cost and size by linking (clustering) personal computers together across a network. Clusters also have the advantage that they can be used as stand-alone computers when they are not operating as a parallel computer. Parallel computing software to exploit clusters is available for computer operating systems like Unix, Windows NT, or Linux. This project concentrates on the use of Windows NT, and the Parallel Virtual Machine (PVM) system to solve an engineering dynamics problem in Fortran

  13. Interval sampling methods and measurement error: a computer simulation.

    Science.gov (United States)

    Wirth, Oliver; Slaven, James; Taylor, Matthew A

    2014-01-01

    A simulation study was conducted to provide a more thorough account of measurement error associated with interval sampling methods. A computer program simulated the application of momentary time sampling, partial-interval recording, and whole-interval recording methods on target events randomly distributed across an observation period. The simulation yielded measures of error for multiple combinations of observation period, interval duration, event duration, and cumulative event duration. The simulations were conducted up to 100 times to yield measures of error variability. Although the present simulation confirmed some previously reported characteristics of interval sampling methods, it also revealed many new findings that pertain to each method's inherent strengths and weaknesses. The analysis and resulting error tables can help guide the selection of the most appropriate sampling method for observation-based behavioral assessments. © Society for the Experimental Analysis of Behavior.

  14. Statistical properties of dynamical systems – Simulation and abstract computation

    International Nuclear Information System (INIS)

    Galatolo, Stefano; Hoyrup, Mathieu; Rojas, Cristóbal

    2012-01-01

    Highlights: ► A survey on results about computation and computability on the statistical properties of dynamical systems. ► Computability and non-computability results for invariant measures. ► A short proof for the computability of the convergence speed of ergodic averages. ► A kind of “constructive” version of the pointwise ergodic theorem. - Abstract: We survey an area of recent development, relating dynamics to theoretical computer science. We discuss some aspects of the theoretical simulation and computation of the long term behavior of dynamical systems. We will focus on the statistical limiting behavior and invariant measures. We present a general method allowing the algorithmic approximation at any given accuracy of invariant measures. The method can be applied in many interesting cases, as we shall explain. On the other hand, we exhibit some examples where the algorithmic approximation of invariant measures is not possible. We also explain how it is possible to compute the speed of convergence of ergodic averages (when the system is known exactly) and how this entails the computation of arbitrarily good approximations of points of the space having typical statistical behaviour (a sort of constructive version of the pointwise ergodic theorem).

  15. simulate_CAT: A Computer Program for Post-Hoc Simulation for Computerized Adaptive Testing

    Directory of Open Access Journals (Sweden)

    İlker Kalender

    2015-06-01

    Full Text Available This paper presents a computer software developed by the author. The software conducts post-hoc simulations for computerized adaptive testing based on real responses of examinees to paper and pencil tests under different parameters that can be defined by user. In this paper, short information is given about post-hoc simulations. After that, the working principle of the software is provided and a sample simulation with required input files is shown. And last, output files are described

  16. Graphical Visualization on Computational Simulation Using Shared Memory

    International Nuclear Information System (INIS)

    Lima, A B; Correa, Eberth

    2014-01-01

    The Shared Memory technique is a powerful tool for parallelizing computer codes. In particular it can be used to visualize the results ''on the fly'' without stop running the simulation. In this presentation we discuss and show how to use the technique conjugated with a visualization code using openGL

  17. A computer simulation of the argument from disagreement

    NARCIS (Netherlands)

    Gustafsson, J.E.; Peterson, M.B.

    2012-01-01

    In this paper we shed new light on the Argument from Disagreement by putting it to test in a computer simulation. According to this argument widespread and persistent disagreement on ethical issues indicates that our moral opinions are not influenced by any moral facts, either because no such facts

  18. Computational Simulation of a Water-Cooled Heat Pump

    Science.gov (United States)

    Bozarth, Duane

    2008-01-01

    A Fortran-language computer program for simulating the operation of a water-cooled vapor-compression heat pump in any orientation with respect to gravity has been developed by modifying a prior general-purpose heat-pump design code used at Oak Ridge National Laboratory (ORNL).

  19. Atomic Force Microscopy and Real Atomic Resolution. Simple Computer Simulations

    NARCIS (Netherlands)

    Koutsos, V.; Manias, E.; Brinke, G. ten; Hadziioannou, G.

    1994-01-01

    Using a simple computer simulation for AFM imaging in the contact mode, pictures with true and false atomic resolution are demonstrated. The surface probed consists of two f.c.c. (111) planes and an atomic vacancy is introduced in the upper layer. Changing the size of the effective tip and its

  20. Improving a Computer Networks Course Using the Partov Simulation Engine

    Science.gov (United States)

    Momeni, B.; Kharrazi, M.

    2012-01-01

    Computer networks courses are hard to teach as there are many details in the protocols and techniques involved that are difficult to grasp. Employing programming assignments as part of the course helps students to obtain a better understanding and gain further insight into the theoretical lectures. In this paper, the Partov simulation engine and…

  1. Computational Fluid Dynamics and Building Energy Performance Simulation

    DEFF Research Database (Denmark)

    Nielsen, Peter V.; Tryggvason, Tryggvi

    An interconnection between a building energy performance simulation program and a Computational Fluid Dynamics program (CFD) for room air distribution will be introduced for improvement of the predictions of both the energy consumption and the indoor environment. The building energy performance...

  2. Highway traffic simulation on multi-processor computers

    Energy Technology Data Exchange (ETDEWEB)

    Hanebutte, U.R.; Doss, E.; Tentner, A.M.

    1997-04-01

    A computer model has been developed to simulate highway traffic for various degrees of automation with a high level of fidelity in regard to driver control and vehicle characteristics. The model simulates vehicle maneuvering in a multi-lane highway traffic system and allows for the use of Intelligent Transportation System (ITS) technologies such as an Automated Intelligent Cruise Control (AICC). The structure of the computer model facilitates the use of parallel computers for the highway traffic simulation, since domain decomposition techniques can be applied in a straight forward fashion. In this model, the highway system (i.e. a network of road links) is divided into multiple regions; each region is controlled by a separate link manager residing on an individual processor. A graphical user interface augments the computer model kv allowing for real-time interactive simulation control and interaction with each individual vehicle and road side infrastructure element on each link. Average speed and traffic volume data is collected at user-specified loop detector locations. Further, as a measure of safety the so- called Time To Collision (TTC) parameter is being recorded.

  3. Computer simulation of Wheeler's delayed-choice experiment with photons

    NARCIS (Netherlands)

    Zhao, S.; Yuan, S.; De Raedt, H.; Michielsen, K.

    We present a computer simulation model of Wheeler's delayed-choice experiment that is a one-to-one copy of an experiment reported recently (Jacques V. et al., Science, 315 (2007) 966). The model is solely based on experimental facts, satisfies Einstein's criterion of local causality and does not

  4. Robotics, Artificial Intelligence, Computer Simulation: Future Applications in Special Education.

    Science.gov (United States)

    Moore, Gwendolyn B.; And Others

    The report describes three advanced technologies--robotics, artificial intelligence, and computer simulation--and identifies the ways in which they might contribute to special education. A hybrid methodology was employed to identify existing technology and forecast future needs. Following this framework, each of the technologies is defined,…

  5. Solving wood chip transport problems with computer simulation.

    Science.gov (United States)

    Dennis P. Bradley; Sharon A. Winsauer

    1976-01-01

    Efficient chip transport operations are difficult to achieve due to frequent and often unpredictable changes in distance to market, chipping rate, time spent at the mill, and equipment costs. This paper describes a computer simulation model that allows a logger to design an efficient transport system in response to these changing factors.

  6. Advanced Simulation and Computing Co-Design Strategy

    Energy Technology Data Exchange (ETDEWEB)

    Ang, James A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hoang, Thuc T. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Kelly, Suzanne M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); McPherson, Allen [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Neely, Rob [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-11-01

    This ASC Co-design Strategy lays out the full continuum and components of the co-design process, based on what we have experienced thus far and what we wish to do more in the future to meet the program’s mission of providing high performance computing (HPC) and simulation capabilities for NNSA to carry out its stockpile stewardship responsibility.

  7. Faster quantum chemistry simulation on fault-tolerant quantum computers

    International Nuclear Information System (INIS)

    Cody Jones, N; McMahon, Peter L; Yamamoto, Yoshihisa; Whitfield, James D; Yung, Man-Hong; Aspuru-Guzik, Alán; Van Meter, Rodney

    2012-01-01

    Quantum computers can in principle simulate quantum physics exponentially faster than their classical counterparts, but some technical hurdles remain. We propose methods which substantially improve the performance of a particular form of simulation, ab initio quantum chemistry, on fault-tolerant quantum computers; these methods generalize readily to other quantum simulation problems. Quantum teleportation plays a key role in these improvements and is used extensively as a computing resource. To improve execution time, we examine techniques for constructing arbitrary gates which perform substantially faster than circuits based on the conventional Solovay–Kitaev algorithm (Dawson and Nielsen 2006 Quantum Inform. Comput. 6 81). For a given approximation error ϵ, arbitrary single-qubit gates can be produced fault-tolerantly and using a restricted set of gates in time which is O(log ϵ) or O(log log ϵ); with sufficient parallel preparation of ancillas, constant average depth is possible using a method we call programmable ancilla rotations. Moreover, we construct and analyze efficient implementations of first- and second-quantized simulation algorithms using the fault-tolerant arbitrary gates and other techniques, such as implementing various subroutines in constant time. A specific example we analyze is the ground-state energy calculation for lithium hydride. (paper)

  8. Pedagogical Approaches to Teaching with Computer Simulations in Science Education

    NARCIS (Netherlands)

    Rutten, N.P.G.; van der Veen, Johan (CTIT); van Joolingen, Wouter; McBride, Ron; Searson, Michael

    2013-01-01

    For this study we interviewed 24 physics teachers about their opinions on teaching with computer simulations. The purpose of this study is to investigate whether it is possible to distinguish different types of teaching approaches. Our results indicate the existence of two types. The first type is

  9. Learner Perceptions of Realism and Magic in Computer Simulations.

    Science.gov (United States)

    Hennessy, Sara; O'Shea, Tim

    1993-01-01

    Discusses the possible lack of credibility in educational interactive computer simulations. Topics addressed include "Shopping on Mars," a collaborative adventure game for arithmetic calculation that uses direct manipulation in the microworld; the Alternative Reality Kit, a graphical animated environment for creating interactive…

  10. Biology Students Building Computer Simulations Using StarLogo TNG

    Science.gov (United States)

    Smith, V. Anne; Duncan, Ishbel

    2011-01-01

    Confidence is an important issue for biology students in handling computational concepts. This paper describes a practical in which honours-level bioscience students simulate complex animal behaviour using StarLogo TNG, a freely-available graphical programming environment. The practical consists of two sessions, the first of which guides students…

  11. Using computer simulations to improve concept formation in chemistry

    African Journals Online (AJOL)

    The goal of this research project was to investigate whether computer simulations used as a visually-supporting teaching strategy, can improve concept formation with regard to molecules and chemical bonding, as found in water. Both the qualitative and quantitative evaluation of responses supported the positive outcome ...

  12. Instructional Advice, Time Advice and Learning Questions in Computer Simulations

    Science.gov (United States)

    Rey, Gunter Daniel

    2010-01-01

    Undergraduate students (N = 97) used an introductory text and a computer simulation to learn fundamental concepts about statistical analyses (e.g., analysis of variance, regression analysis and General Linear Model). Each learner was randomly assigned to one cell of a 2 (with or without instructional advice) x 2 (with or without time advice) x 2…

  13. Student generated assignments about electrical circuits in a computer simulation

    NARCIS (Netherlands)

    Vreman-de Olde, Cornelise; de Jong, Anthonius J.M.

    2004-01-01

    In this study we investigated the design of assignments by students as a knowledge-generating activity. Students were required to design assignments for 'other students' in a computer simulation environment about electrical circuits. Assignments consisted of a question, alternatives, and feedback on

  14. Plant process computer system upgrades at the KSG simulator centre

    International Nuclear Information System (INIS)

    2006-01-01

    The human-machine interface (HMI) of a modern plant process computer system (PPC) differs significantly from that of older systems. Along with HMI changes, there are often improvements to system functionality such as alarm display and printing functions and transient data analysis capabilities. Therefore, the upgrade or replacement of a PPC in the reference plant will typically require an upgrade of the simulator (see Section 6.5.1 for additional information). Several options are available for this type of project including stimulation of a replica system,or emulation, or simulation of PPC functionality within the simulation environment. To simulate or emulate a PCC, detailed knowledge of hardware and software functionality is required. This is typically vendor proprietary information, which leads to licensing and other complications. One of the added benefits of stimulating the PPC system is that the simulator can be used as a test bed for functional testing (i.e. verification and validation) of the system prior to installation in the reference plant. Some of this testing may include validation of the process curve and system diagram displays. Over the past few years several German NPPs decided to modernize their plant process computer (PPC) systems. After the NPPs had selected the desired system to meet their requirements the question arose how to modernize the PPC systems on the corresponding simulators. Six German NPPs selected the same PPC system from the same vendor and it was desired to perform integral tests of the HMI on the simulators. In this case the vendor offered a stimulated variant of their system and it therefore made sense to choose that implementation method for upgrade of the corresponding simulators. The first simulator PPC modernization project can be considered as a prototype project for the follow-on projects. In general, from the simulator project execution perspective the implementation of several stimulated PPC systems of the same type

  15. SPINET: A Parallel Computing Approach to Spine Simulations

    Directory of Open Access Journals (Sweden)

    Peter G. Kropf

    1996-01-01

    Full Text Available Research in scientitic programming enables us to realize more and more complex applications, and on the other hand, application-driven demands on computing methods and power are continuously growing. Therefore, interdisciplinary approaches become more widely used. The interdisciplinary SPINET project presented in this article applies modern scientific computing tools to biomechanical simulations: parallel computing and symbolic and modern functional programming. The target application is the human spine. Simulations of the spine help us to investigate and better understand the mechanisms of back pain and spinal injury. Two approaches have been used: the first uses the finite element method for high-performance simulations of static biomechanical models, and the second generates a simulation developmenttool for experimenting with different dynamic models. A finite element program for static analysis has been parallelized for the MUSIC machine. To solve the sparse system of linear equations, a conjugate gradient solver (iterative method and a frontal solver (direct method have been implemented. The preprocessor required for the frontal solver is written in the modern functional programming language SML, the solver itself in C, thus exploiting the characteristic advantages of both functional and imperative programming. The speedup analysis of both solvers show very satisfactory results for this irregular problem. A mixed symbolic-numeric environment for rigid body system simulations is presented. It automatically generates C code from a problem specification expressed by the Lagrange formalism using Maple.

  16. A Computational Framework for Efficient Low Temperature Plasma Simulations

    Science.gov (United States)

    Verma, Abhishek Kumar; Venkattraman, Ayyaswamy

    2016-10-01

    Over the past years, scientific computing has emerged as an essential tool for the investigation and prediction of low temperature plasmas (LTP) applications which includes electronics, nanomaterial synthesis, metamaterials etc. To further explore the LTP behavior with greater fidelity, we present a computational toolbox developed to perform LTP simulations. This framework will allow us to enhance our understanding of multiscale plasma phenomenon using high performance computing tools mainly based on OpenFOAM FVM distribution. Although aimed at microplasma simulations, the modular framework is able to perform multiscale, multiphysics simulations of physical systems comprises of LTP. Some salient introductory features are capability to perform parallel, 3D simulations of LTP applications on unstructured meshes. Performance of the solver is tested based on numerical results assessing accuracy and efficiency of benchmarks for problems in microdischarge devices. Numerical simulation of microplasma reactor at atmospheric pressure with hemispherical dielectric coated electrodes will be discussed and hence, provide an overview of applicability and future scope of this framework.

  17. Face, content and construct validity of a virtual reality simulator for robotic surgery (SEP Robot).

    Science.gov (United States)

    Gavazzi, Andrea; Bahsoun, Ali N; Van Haute, Wim; Ahmed, Kamran; Elhage, Oussama; Jaye, Peter; Khan, M Shamim; Dasgupta, Prokar

    2011-03-01

    This study aims to establish face, content and construct validation of the SEP Robot (SimSurgery, Oslo, Norway) in order to determine its value as a training tool. The tasks used in the validation of this simulator were arrow manipulation and performing a surgeon's knot. Thirty participants (18 novices, 12 experts) completed the procedures. The simulator was able to differentiate between experts and novices in several respects. The novice group required more time to complete the tasks than the expert group, especially suturing. During the surgeon's knot exercise, experts significantly outperformed novices in maximum tightening stretch, instruments dropped, maximum winding stretch and tool collisions in addition to total task time. A trend was found towards the use of less force by the more experienced participants. The SEP robotic simulator has demonstrated face, content and construct validity as a virtual reality simulator for robotic surgery. With steady increase in adoption of robotic surgery world-wide, this simulator may prove to be a valuable adjunct to clinical mentorship.

  18. High correlation between performance on a virtual-reality simulator and real-life cataract surgery

    DEFF Research Database (Denmark)

    Thomsen, Ann Sofia Skou; Smith, Phillip; Subhi, Yousif

    2017-01-01

    -tracking software of cataract surgical videos with a Pearson correlation coefficient of -0.70 (p = 0.017). CONCLUSION: Performance on the EyeSi simulator is significantly and highly correlated to real-life surgical performance. However, it is recommended that performance assessments are made using multiple data......PURPOSE: To investigate the correlation in performance of cataract surgery between a virtual-reality simulator and real-life surgery using two objective assessment tools with evidence of validity. METHODS: Cataract surgeons with varying levels of experience were included in the study. All...... antitremor training, forceps training, bimanual training, capsulorhexis and phaco divide and conquer. RESULTS: Eleven surgeons were enrolled. After a designated warm-up period, the proficiency-based test on the EyeSi simulator was strongly correlated to real-life performance measured by motion...

  19. Bibliography for Verification and Validation in Computational Simulation

    International Nuclear Information System (INIS)

    Oberkampf, W.L.

    1998-01-01

    A bibliography has been compiled dealing with the verification and validation of computational simulations. The references listed in this bibliography are concentrated in the field of computational fluid dynamics (CFD). However, references from the following fields are also included: operations research, heat transfer, solid dynamics, software quality assurance, software accreditation, military systems, and nuclear reactor safety. This bibliography, containing 221 references, is not meant to be comprehensive. It was compiled during the last ten years in response to the author's interest and research in the methodology for verification and validation. The emphasis in the bibliography is in the following areas: philosophy of science underpinnings, development of terminology and methodology, high accuracy solutions for CFD verification, experimental datasets for CFD validation, and the statistical quantification of model validation. This bibliography should provide a starting point for individual researchers in many fields of computational simulation in science and engineering

  20. Bibliography for Verification and Validation in Computational Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Oberkampf, W.L.

    1998-10-01

    A bibliography has been compiled dealing with the verification and validation of computational simulations. The references listed in this bibliography are concentrated in the field of computational fluid dynamics (CFD). However, references from the following fields are also included: operations research, heat transfer, solid dynamics, software quality assurance, software accreditation, military systems, and nuclear reactor safety. This bibliography, containing 221 references, is not meant to be comprehensive. It was compiled during the last ten years in response to the author's interest and research in the methodology for verification and validation. The emphasis in the bibliography is in the following areas: philosophy of science underpinnings, development of terminology and methodology, high accuracy solutions for CFD verification, experimental datasets for CFD validation, and the statistical quantification of model validation. This bibliography should provide a starting point for individual researchers in many fields of computational simulation in science and engineering.

  1. AFFECTIVE COMPUTING AND AUGMENTED REALITY FOR CAR DRIVING SIMULATORS

    Directory of Open Access Journals (Sweden)

    Dragoș Datcu

    2017-12-01

    Full Text Available Car simulators are essential for training and for analyzing the behavior, the responses and the performance of the driver. Augmented Reality (AR is the technology that enables virtual images to be overlaid on views of the real world. Affective Computing (AC is the technology that helps reading emotions by means of computer systems, by analyzing body gestures, facial expressions, speech and physiological signals. The key aspect of the research relies on investigating novel interfaces that help building situational awareness and emotional awareness, to enable affect-driven remote collaboration in AR for car driving simulators. The problem addressed relates to the question about how to build situational awareness (using AR technology and emotional awareness (by AC technology, and how to integrate these two distinct technologies [4], into a unique affective framework for training, in a car driving simulator.

  2. Man-machine interfaces analysis system based on computer simulation

    International Nuclear Information System (INIS)

    Chen Xiaoming; Gao Zuying; Zhou Zhiwei; Zhao Bingquan

    2004-01-01

    The paper depicts a software assessment system, Dynamic Interaction Analysis Support (DIAS), based on computer simulation technology for man-machine interfaces (MMI) of a control room. It employs a computer to simulate the operation procedures of operations on man-machine interfaces in a control room, provides quantified assessment, and at the same time carries out analysis on operational error rate of operators by means of techniques for human error rate prediction. The problems of placing man-machine interfaces in a control room and of arranging instruments can be detected from simulation results. DIAS system can provide good technical supports to the design and improvement of man-machine interfaces of the main control room of a nuclear power plant

  3. Computational Modeling for Enhancing Soft Tissue Image Guided Surgery: An Application in Neurosurgery.

    Science.gov (United States)

    Miga, Michael I

    2016-01-01

    With the recent advances in computing, the opportunities to translate computational models to more integrated roles in patient treatment are expanding at an exciting rate. One area of considerable development has been directed towards correcting soft tissue deformation within image guided neurosurgery applications. This review captures the efforts that have been undertaken towards enhancing neuronavigation by the integration of soft tissue biomechanical models, imaging and sensing technologies, and algorithmic developments. In addition, the review speaks to the evolving role of modeling frameworks within surgery and concludes with some future directions beyond neurosurgical applications.

  4. 3D Surgical Simulation

    OpenAIRE

    Cevidanes, Lucia; Tucker, Scott; Styner, Martin; Kim, Hyungmin; Chapuis, Jonas; Reyes, Mauricio; Proffit, William; Turvey, Timothy; Jaskolka, Michael

    2010-01-01

    This paper discusses the development of methods for computer-aided jaw surgery. Computer-aided jaw surgery allows us to incorporate the high level of precision necessary for transferring virtual plans into the operating room. We also present a complete computer-aided surgery (CAS) system developed in close collaboration with surgeons. Surgery planning and simulation include construction of 3D surface models from Cone-beam CT (CBCT), dynamic cephalometry, semi-automatic mirroring, interactive ...

  5. Educational program in crisis management for cardiac surgery teams including high realism simulation.

    Science.gov (United States)

    Stevens, Louis-Mathieu; Cooper, Jeffrey B; Raemer, Daniel B; Schneider, Robert C; Frankel, Allan S; Berry, William R; Agnihotri, Arvind K

    2012-07-01

    Cardiac surgery demands effective teamwork for safe, high-quality care. The objective of this pilot study was to develop a comprehensive program to sharpen performance of experienced cardiac surgical teams in acute crisis management. We developed and implemented an educational program for cardiac surgery based on high realism acute crisis simulation scenarios and interactive whole-unit workshop. The impact of these interventions was assessed with postintervention questionnaires, preintervention and 6-month postintervention surveys, and structured interviews. The realism of the acute crisis simulation scenarios gradually improved; most participants rated both the simulation and whole-unit workshop as very good or excellent. Repeat simulation training was recommended every 6 to 12 months by 82% of the participants. Participants of the interactive workshop identified 2 areas of highest priority: encouraging speaking up about critical information and interprofessional information sharing. They also stressed the importance of briefings, early communication of surgical plan, knowing members of the team, and continued simulation for practice. The pre/post survey response rates were 70% (55/79) and 66% (52/79), respectively. The concept of working as a team improved between surveys (P = .028), with a trend for improvement in gaining common understanding of the plan before a procedure (P = .075) and appropriate resolution of disagreements (P = .092). Interviewees reported that the training had a positive effect on their personal behaviors and patient care, including speaking up more readily and communicating more clearly. Comprehensive team training using simulation and a whole-unit interactive workshop can be successfully deployed for experienced cardiac surgery teams with demonstrable benefits in participant's perception of team performance. Copyright © 2012 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

  6. Automatic Model Generation Framework for Computational Simulation of Cochlear Implantation

    DEFF Research Database (Denmark)

    Mangado Lopez, Nerea; Ceresa, Mario; Duchateau, Nicolas

    2016-01-01

    . To address such a challenge, we propose an automatic framework for the generation of patient-specific meshes for finite element modeling of the implanted cochlea. First, a statistical shape model is constructed from high-resolution anatomical μCT images. Then, by fitting the statistical model to a patient......'s CT image, an accurate model of the patient-specific cochlea anatomy is obtained. An algorithm based on the parallel transport frame is employed to perform the virtual insertion of the cochlear implant. Our automatic framework also incorporates the surrounding bone and nerve fibers and assigns......Recent developments in computational modeling of cochlear implantation are promising to study in silico the performance of the implant before surgery. However, creating a complete computational model of the patient's anatomy while including an external device geometry remains challenging...

  7. A Systematic Review of Virtual Reality Simulators for Robot-assisted Surgery.

    Science.gov (United States)

    Moglia, Andrea; Ferrari, Vincenzo; Morelli, Luca; Ferrari, Mauro; Mosca, Franco; Cuschieri, Alfred

    2016-06-01

    No single large published randomized controlled trial (RCT) has confirmed the efficacy of virtual simulators in the acquisition of skills to the standard required for safe clinical robotic surgery. This remains the main obstacle for the adoption of these virtual simulators in surgical residency curricula. To evaluate the level of evidence in published studies on the efficacy of training on virtual simulators for robotic surgery. In April 2015 a literature search was conducted on PubMed, Web of Science, Scopus, Cochrane Library, the Clinical Trials Database (US) and the Meta Register of Controlled Trials. All publications were scrutinized for relevance to the review and for assessment of the levels of evidence provided using the classification developed by the Oxford Centre for Evidence-Based Medicine. The publications included in the review consisted of one RCT and 28 cohort studies on validity, and seven RCTs and two cohort studies on skills transfer from virtual simulators to robot-assisted surgery. Simulators were rated good for realism (face validity) and for usefulness as a training tool (content validity). However, the studies included used various simulation training methodologies, limiting the assessment of construct validity. The review confirms the absence of any consensus on which tasks and metrics are the most effective for the da Vinci Skills Simulator and dV-Trainer, the most widely investigated systems. Although there is consensus for the RoSS simulator, this is based on only two studies on construct validity involving four exercises. One study on initial evaluation of an augmented reality module for partial nephrectomy using the dV-Trainer reported high correlation (r=0.8) between in vivo porcine nephrectomy and a virtual renorrhaphy task according to the overall Global Evaluation Assessment of Robotic Surgery (GEARS) score. In one RCT on skills transfer, the experimental group outperformed the control group, with a significant difference in overall

  8. Using virtual reality simulation to assess competence in video-assisted thoracoscopic surgery (VATS) lobectomy.

    Science.gov (United States)

    Jensen, Katrine; Bjerrum, Flemming; Hansen, Henrik Jessen; Petersen, René Horsleben; Pedersen, Jesper Holst; Konge, Lars

    2017-06-01

    The societies of thoracic surgery are working to incorporate simulation and competency-based assessment into specialty training. One challenge is the development of a simulation-based test, which can be used as an assessment tool. The study objective was to establish validity evidence for a virtual reality simulator test of a video-assisted thoracoscopic surgery (VATS) lobectomy of a right upper lobe. Participants with varying experience in VATS lobectomy were included. They were familiarized with a virtual reality simulator (LapSim ® ) and introduced to the steps of the procedure for a VATS right upper lobe lobectomy. The participants performed two VATS lobectomies on the simulator with a 5-min break between attempts. Nineteen pre-defined simulator metrics were recorded. Fifty-three participants from nine different countries were included. High internal consistency was found for the metrics with Cronbach's alpha coefficient for standardized items of 0.91. Significant test-retest reliability was found for 15 of the metrics (p-values 50 VATS lobectomies performed). A pass/fail level defined as approximately one standard deviation from the mean metric scores for experienced surgeons passed none of the novices (0 % false positives) and failed four of the experienced surgeons (29 % false negatives). This study is the first to establish validity evidence for a VATS right upper lobe lobectomy virtual reality simulator test. Several simulator metrics demonstrated significant differences between novices and experienced surgeons and pass/fail criteria for the test were set with acceptable consequences. This test can be used as a first step in assessing thoracic surgery trainees' VATS lobectomy competency.

  9. The rationale for combining an online audiovisual curriculum with simulation to better educate general surgery trainees.

    Science.gov (United States)

    AlJamal, Yazan N; Ali, Shahzad M; Ruparel, Raaj K; Brahmbhatt, Rushin D; Yadav, Siddhant; Farley, David R

    2014-09-01

    Surgery interns' training has historically been weighted toward patient care, operative observation, and sleeping when possible. With more protected free time and less clinical time, real educational hours for trainees in 2013 are precious. We created a 20-session (3 hours each) simulation curriculum (with pre- and post-tests) and a 24/7 online audiovisual (AV) curriculum for surgery interns. Friday morning simulation sessions emphasize operative skills and judgment. AV clips (using operating room, whiteboard, and simulation center videos) take learners through 20 different general surgery operations with follow-up quizzes. We report our early experience with this novel setup. Thirty-two surgical interns (2012-2013) attended simulation sessions on 20 separate subjects (hernia, breast, hepatobiliary, endocrine, etc). Post-test scores improved (P 4.5; Likert scale, 1-5). The AV curriculum feedback is similar (mean, >4.3) and usage is available 24/7 preparing learners for both operating room and simulation sessions. Most simulation sessions utilize low-fidelity models to keep costs <$50 per session. Scores on our semiannual Surgical Olympics (mean score of 49.6 in July vs 82.9 in January; P < .05) improved significantly, suggesting that interns are improving their surgical skills and knowledge. Residents enjoy and learn from the step-by-step, in-house, AV curriculum and both appreciate and thrive on the 'hands-on' simulation sessions mimicking operations they see in real operating rooms. The cost of these programs is not prohibitive and the programs offer simulated repetitions for duty-hour-regulated trainees. Copyright © 2014 Mosby, Inc. All rights reserved.

  10. Computer simulation of human motion in sports biomechanics.

    Science.gov (United States)

    Vaughan, C L

    1984-01-01

    This chapter has covered some important aspects of the computer simulation of human motion in sports biomechanics. First the definition and the advantages and limitations of computer simulation were discussed; second, research on various sporting activities were reviewed. These activities included basic movements, aquatic sports, track and field athletics, winter sports, gymnastics, and striking sports. This list was not exhaustive and certain material has, of necessity, been omitted. However, it was felt that a sufficiently broad and interesting range of activities was chosen to illustrate both the advantages and the pitfalls of simulation. It is almost a decade since Miller [53] wrote a review chapter similar to this one. One might be tempted to say that things have changed radically since then--that computer simulation is now a widely accepted and readily applied research tool in sports biomechanics. This is simply not true, however. Biomechanics researchers still tend to emphasize the descriptive type of study, often unfortunately, when a little theoretical explanation would have been more helpful [29]. What will the next decade bring? Of one thing we can be certain: The power of computers, particularly the readily accessible and portable microcomputer, will expand beyond all recognition. The memory and storage capacities will increase dramatically on the hardware side, and on the software side the trend will be toward "user-friendliness." It is likely that a number of software simulation packages designed specifically for studying human motion [31, 96] will be extensively tested and could gain wide acceptance in the biomechanics research community. Nevertheless, a familiarity with Newtonian and Lagrangian mechanics, optimization theory, and computers in general, as well as practical biomechanical insight, will still be a prerequisite for successful simulation models of human motion. Above all, the biomechanics researcher will still have to bear in mind that

  11. What is going on in augmented reality simulation in laparoscopic surgery?

    Science.gov (United States)

    Botden, Sanne M B I; Jakimowicz, Jack J

    2009-08-01

    To prevent unnecessary errors and adverse results of laparoscopic surgery, proper training is of paramount importance. A safe way to train surgeons for laparoscopic skills is simulation. For this purpose traditional box trainers are often used, however they lack objective assessment of performance. Virtual reality laparoscopic simulators assess performance, but lack realistic haptic feedback. Augmented reality (AR) combines a virtual reality (VR) setting with real physical materials, instruments, and feedback. This article presents the current developments in augmented reality laparoscopic simulation. Pubmed searches were performed to identify articles regarding surgical simulation and augmented reality. Identified companies manufacturing an AR laparoscopic simulator received the same questionnaire referring to the features of the simulator. Seven simulators that fitted the definition of augmented reality were identified during the literature search. Five of the approached manufacturers returned a completed questionnaire, of which one simulator appeared to be VR and was therefore not applicable for this review. Several augmented reality simulators have been developed over the past few years and they are improving rapidly. We recommend the development of AR laparoscopic simulators for component tasks of procedural training. AR simulators should be implemented in current laparoscopic training curricula, in particular for laparoscopic suturing training.

  12. Adaptive scapula bone remodeling computational simulation: Relevance to regenerative medicine

    International Nuclear Information System (INIS)

    Sharma, Gulshan B.; Robertson, Douglas D.

    2013-01-01

    Shoulder arthroplasty success has been attributed to many factors including, bone quality, soft tissue balancing, surgeon experience, and implant design. Improved long-term success is primarily limited by glenoid implant loosening. Prosthesis design examines materials and shape and determines whether the design should withstand a lifetime of use. Finite element (FE) analyses have been extensively used to study stresses and strains produced in implants and bone. However, these static analyses only measure a moment in time and not the adaptive response to the altered environment produced by the therapeutic intervention. Computational analyses that integrate remodeling rules predict how bone will respond over time. Recent work has shown that subject-specific two- and three dimensional adaptive bone remodeling models are feasible and valid. Feasibility and validation were achieved computationally, simulating bone remodeling using an intact human scapula, initially resetting the scapular bone material properties to be uniform, numerically simulating sequential loading, and comparing the bone remodeling simulation results to the actual scapula’s material properties. Three-dimensional scapula FE bone model was created using volumetric computed tomography images. Muscle and joint load and boundary conditions were applied based on values reported in the literature. Internal bone remodeling was based on element strain-energy density. Initially, all bone elements were assigned a homogeneous density. All loads were applied for 10 iterations. After every iteration, each bone element’s remodeling stimulus was compared to its corresponding reference stimulus and its material properties modified. The simulation achieved convergence. At the end of the simulation the predicted and actual specimen bone apparent density were plotted and compared. Location of high and low predicted bone density was comparable to the actual specimen. High predicted bone density was greater than

  13. Computational physics simulation of classical and quantum systems

    CERN Document Server

    Scherer, Philipp O J

    2013-01-01

    This textbook presents basic and advanced computational physics in a very didactic style. It contains very-well-presented and simple mathematical descriptions of many of the most important algorithms used in computational physics. Many clear mathematical descriptions of important techniques in computational physics are given. The first part of the book discusses the basic numerical methods. A large number of exercises and computer experiments allows to study the properties of these methods. The second part concentrates on simulation of classical and quantum systems. It uses a rather general concept for the equation of motion which can be applied to ordinary and partial differential equations. Several classes of integration methods are discussed including not only the standard Euler and Runge Kutta method but also multistep methods and the class of Verlet methods which is introduced by studying the motion in Liouville space. Besides the classical methods, inverse interpolation is discussed, together with the p...

  14. Two-dimensional computer simulation of high intensity proton beams

    CERN Document Server

    Lapostolle, Pierre M

    1972-01-01

    A computer program has been developed which simulates the two- dimensional transverse behaviour of a proton beam in a focusing channel. The model is represented by an assembly of a few thousand 'superparticles' acted upon by their own self-consistent electric field and an external focusing force. The evolution of the system is computed stepwise in time by successively solving Poisson's equation and Newton's law of motion. Fast Fourier transform techniques are used for speed in the solution of Poisson's equation, while extensive area weighting is utilized for the accurate evaluation of electric field components. A computer experiment has been performed on the CERN CDC 6600 computer to study the nonlinear behaviour of an intense beam in phase space, showing under certain circumstances a filamentation due to space charge and an apparent emittance growth. (14 refs).

  15. Cosmic reionization on computers. I. Design and calibration of simulations

    Energy Technology Data Exchange (ETDEWEB)

    Gnedin, Nickolay Y., E-mail: gnedin@fnal.gov [Particle Astrophysics Center, Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States)

    2014-09-20

    Cosmic Reionization On Computers is a long-term program of numerical simulations of cosmic reionization. Its goal is to model fully self-consistently (albeit not necessarily from the first principles) all relevant physics, from radiative transfer to gas dynamics and star formation, in simulation volumes of up to 100 comoving Mpc, and with spatial resolution approaching 100 pc in physical units. In this method paper, we describe our numerical method, the design of simulations, and the calibration of numerical parameters. Using several sets (ensembles) of simulations in 20 h {sup –1} Mpc and 40 h {sup –1} Mpc boxes with spatial resolution reaching 125 pc at z = 6, we are able to match the observed galaxy UV luminosity functions at all redshifts between 6 and 10, as well as obtain reasonable agreement with the observational measurements of the Gunn-Peterson optical depth at z < 6.

  16. Ravenscar Computational Model compliant AADL Simulation on LEON2

    Directory of Open Access Journals (Sweden)

    Roberto Varona-Gómez

    2013-02-01

    Full Text Available AADL has been proposed for designing and analyzing SW and HW architectures for real-time mission-critical embedded systems. Although the Behavioral Annex improves its simulation semantics, AADL is a language for analyzing architectures and not for simulating them. AADS-T is an AADL simulation tool that supports the performance analysis of the AADL specification throughout the refinement process from the initial system architecture until the complete, detailed application and execution platform are developed. In this way, AADS-T enables the verification of the initial timing constraints during the complete design process. In this paper we focus on the compatibility of AADS-T with the Ravenscar Computational Model (RCM as part of the TASTE toolset. Its flexibility enables AADS-T to support different processors. In this work we have focused on performing the simulation on a LEON2 processor.

  17. Optimizing patient flow in a large hospital surgical centre by means of discrete-event computer simulation models.

    Science.gov (United States)

    Ferreira, Rodrigo B; Coelli, Fernando C; Pereira, Wagner C A; Almeida, Renan M V R

    2008-12-01

    This study used the discrete-events computer simulation methodology to model a large hospital surgical centre (SC), in order to analyse the impact of increases in the number of post-anaesthetic beds (PABs), of changes in surgical room scheduling strategies and of increases in surgery numbers. The used inputs were: number of surgeries per day, type of surgical room scheduling, anaesthesia and surgery duration, surgical teams' specialty and number of PABs, and the main outputs were: number of surgeries per day, surgical rooms' use rate and blocking rate, surgical teams' use rate, patients' blocking rate, surgery delays (minutes) and the occurrence of postponed surgeries. Two basic strategies were implemented: in the first strategy, the number of PABs was increased under two assumptions: (a) following the scheduling plan actually used by the hospital (the 'rigid' scheduling - surgical rooms were previously assigned and assignments could not be changed) and (b) following a 'flexible' scheduling (surgical rooms, when available, could be freely used by any surgical team). In the second, the same analysis was performed, increasing the number of patients (up to the system 'feasible maximum') but fixing the number of PABs, in order to evaluate the impact of the number of patients over surgery delays. It was observed that the introduction of a flexible scheduling/increase in PABs would lead to a significant improvement in the SC productivity.

  18. Computer simulation of two-phase flow in nuclear reactors

    International Nuclear Information System (INIS)

    Wulff, W.

    1993-01-01

    Two-phase flow models dominate the requirements of economic resources for the development and use of computer codes which serve to analyze thermohydraulic transients in nuclear power plants. An attempt is made to reduce the effort of analyzing reactor transients by combining purpose-oriented modelling with advanced computing techniques. Six principles are presented on mathematical modeling and the selection of numerical methods, along with suggestions on programming and machine selection, all aimed at reducing the cost of analysis. Computer simulation is contrasted with traditional computer calculation. The advantages of run-time interactive access operation in a simulation environment are demonstrated. It is explained that the drift-flux model is better suited than the two-fluid model for the analysis of two-phase flow in nuclear reactors, because of the latter's closure problems. The advantage of analytical over numerical integration is demonstrated. Modeling and programming techniques are presented which minimize the number of needed arithmetical and logical operations and thereby increase the simulation speed, while decreasing the cost. (orig.)

  19. Monte Carlo simulation with the Gate software using grid computing

    International Nuclear Information System (INIS)

    Reuillon, R.; Hill, D.R.C.; Gouinaud, C.; El Bitar, Z.; Breton, V.; Buvat, I.

    2009-03-01

    Monte Carlo simulations are widely used in emission tomography, for protocol optimization, design of processing or data analysis methods, tomographic reconstruction, or tomograph design optimization. Monte Carlo simulations needing many replicates to obtain good statistical results can be easily executed in parallel using the 'Multiple Replications In Parallel' approach. However, several precautions have to be taken in the generation of the parallel streams of pseudo-random numbers. In this paper, we present the distribution of Monte Carlo simulations performed with the GATE software using local clusters and grid computing. We obtained very convincing results with this large medical application, thanks to the EGEE Grid (Enabling Grid for E-science), achieving in one week computations that could have taken more than 3 years of processing on a single computer. This work has been achieved thanks to a generic object-oriented toolbox called DistMe which we designed to automate this kind of parallelization for Monte Carlo simulations. This toolbox, written in Java is freely available on SourceForge and helped to ensure a rigorous distribution of pseudo-random number streams. It is based on the use of a documented XML format for random numbers generators statuses. (authors)

  20. Image calibration and registration in cone-beam computed tomogram for measuring the accuracy of computer-aided implant surgery

    Science.gov (United States)

    Lam, Walter Y. H.; Ngan, Henry Y. T.; Wat, Peter Y. P.; Luk, Henry W. K.; Goto, Tazuko K.; Pow, Edmond H. N.

    2015-02-01

    Medical radiography is the use of radiation to "see through" a human body without breaching its integrity (surface). With computed tomography (CT)/cone beam computed tomography (CBCT), three-dimensional (3D) imaging can be produced. These imagings not only facilitate disease diagnosis but also enable computer-aided surgical planning/navigation. In dentistry, the common method for transfer of the virtual surgical planning to the patient (reality) is the use of surgical stent either with a preloaded planning (static) like a channel or a real time surgical navigation (dynamic) after registration with fiducial markers (RF). This paper describes using the corner of a cube as a radiopaque fiducial marker on an acrylic (plastic) stent, this RF allows robust calibration and registration of Cartesian (x, y, z)- coordinates for linking up the patient (reality) and the imaging (virtuality) and hence the surgical planning can be transferred in either static or dynamic way. The accuracy of computer-aided implant surgery was measured with reference to coordinates. In our preliminary model surgery, a dental implant was planned virtually and placed with preloaded surgical guide. The deviation of the placed implant apex from the planning was x=+0.56mm [more right], y=- 0.05mm [deeper], z=-0.26mm [more lingual]) which was within clinically 2mm safety range. For comparison with the virtual planning, the physically placed implant was CT/CBCT scanned and errors may be introduced. The difference of the actual implant apex to the virtual apex was x=0.00mm, y=+0.21mm [shallower], z=-1.35mm [more lingual] and this should be brought in mind when interpret the results.