Specification and Automatic Generation of Simulation Models with Applications in Semiconductor Manufacturing

The creation of large-scale simulation models is a difficult and time-consuming task. Yet simulation is one of the techniques most frequently used by practitioners in Operations Research and Industrial Engineering, as it is less limited by modeling assumptions than many analytical methods. The effective generation of simulation models is an important challenge. Due to the rapid increase in computing power, it is possible to simulate significantly larger systems than in the past. However, the verification and validation of these large-scale simulations is typically a very challenging task. This thesis introduces a simulation framework that can generate a large variety of manufacturing simulation models. These models have to be described with a simulation data specification. This specification is then used to generate a simulation model which is described as a Petri net. This approach reduces the effort of model verification. The proposed Petri net data structure has extensions for time and token priorities. Since it builds on existing theory for classical Petri nets, it is possible to make certain assertions about the behavior of the generated simulation model. The elements of the proposed framework and the simulation execution mechanism are described in detail. Measures of complexity for simulation models that are built with the framework are also developed. The applicability of the framework to real-world systems is demonstrated by means of a semiconductor manufacturing system simulation model.Ph.D.Committee Chair: Alexopoulos, Christos; Committee Co-Chair: McGinnis, Leon; Committee Member: Egerstedt, Magnus; Committee Member: Fujimoto, Richard; Committee Member: Goldsman, Davi

Collaboration in Automotive - The Eclipse Automotive Industry Working Group

International audienceThe Automotive Industry is constantly introducing new and improved features based on advanced electronics and software. The use of these consumer electronics and software has required the automotive industry to define processes and tools that manage the interactions within an organization and within their extended supply chain. To address the growing complexity and time-to-market pressures , the automotive industry needs a common development tool-chain to support the development and testing of these new types of features. Today, many automotive companies use Eclipse to assist in the development of new features. However, a lack of integration between technology stacks, consistent use of tools throughout the supply chain and missing functionality has limited the effectiveness of create a complete development tool-chain. OEMs, 1st-tiers and consutling companies are founding the Eclipse Autmotive Industry Working Group to coordinate the activites within companies

Hardware Implementation of a Visual-Motion Pixel Using Oriented Spatiotemporal Neural Filters

A pixel for measuring two-dimensional (2-D) visual motion with two one-dimensional (1-D) detectors has been implemented in very large scale integration. Based on the spatiotemporal feature extraction model of Adelson and Bergen, the pixel is realized using a general-purpose analog neural computer and a silicon retina. Because the neural computer only offers sum-and-threshold neurons, the Adelson and Bergen\u27s model is modified. The quadratic nonlinearity is replaced with a full-wave rectification, while the contrast normalization is replaced with edge detection and thresholding. Motion is extracted in two dimensions by using two 1-D detectors with spatial smoothing orthogonal to the direction of motion. Analysis shows that our pixel, although it has some limitations, has much lower hardware complexity compared to the full 2-D model. It also produces more accurate results and has a reduced aperture problem compared to the two 1-D model with no smoothing. Real-time velocity is represented as a distribution of activity of the 18 X and 18 Y velocity-tuned neural filter

PET-CT-guided interventions in the management of FDG-positive lesions in patients suffering from solid malignancies: initial experiences

Positron emission tomography-computed tomography (PET-CT) has gained widespread acceptance as a staging investigation in the diagnostic workup of malignant tumours and may be used to visualize metabolic changes before the evolution of morphological changes. To make histology of PET findings without distinctive structural changes available for treatment decisions, we developed a protocol for multimodal image-guided interventions using an integrated PET-CT machine. We report our first experience in 12 patients admitted for staging and restaging of breast cancer, non-small cell lung cancer, cervical cancer, soft tissue sarcoma, and osteosarcoma. Patients were repositioned according to the findings in PET-CT and intervention was planned based on a subsequent single-bed PET-CT acquisition of the region concerned. The needle was introduced under CT guidance in a step-by-step technique and correct needle position in the centre of the FDG avid lesion was assured by repetition of a single-bed PET-CT acquisition before sampling. The metabolically active part of lesions was accurately targeted in all patients and representative samples were obtained in 92%. No major adverse effects occurred. We conclude that PET-CT guidance for interventions is feasible and may be promising to optimize the diagnostic yield of CT-guided interventions and to make metabolically active lesions without morphological correlate accessible to percutaneous intervention

A Foveated Silicon Retina for Two-Dimensional Tracking

A silicon retina chip with a central foveal region for smooth-pursuit tracking and a peripheral region for saccadic target acquisition is presented. The foveal region contains a 9 x 9 dense array of large dynamic range photoreceptors and edge detectors. Two-dimensional direction of foveal motion is computed outside the imaging array. The peripheral region contains a sparse array of 19 x 17 similar, but larger, photoreceptors with in-pixel edge and temporal ON-set detection. The coordinates of moving or flashing targets are computed with two one-dimensional centroid localization circuits located on the outskirts of the peripheral region. The chip is operational for ambient intensities ranging over six orders of magnitude, targets contrast as low as 10%, foveal speed ranging from 1.5 to 10K pixels/s, and peripheral ON-set frequencies from \u3c0.1 to 800 kHz. The chip is implemented in 2-μm N well CMOS process and consumes 15 mW (V dd = 4 V) in normal indoor light (25 μW/cm2). It has been used as a person tracker in a smart surveillance system and a road follower in an autonomous navigation system

PET/CT-guided biopsies of metabolically active bone lesions: applications and clinical impact

Purpose: In a minority of cases a definite diagnosis and stage grouping in cancer patients is not possible based on the imaging information of PET/CT. We report our experience with percutaneous PET/CT-guided bone biopsies to histologically verify the aetiology of hypermetabolic bone lesions. Methods: We retrospectively reviewed the data of 20 consecutive patients who underwent multimodal image-guided bone biopsies using a dedicated PET/CT system in a step-by-step technique. Technical and clinical success rates of PET/CT-guided biopsies were evaluated. Questionnaires were sent to the referring physicians to assess the impact of biopsies on patient management and to check the clinical need for PET/CT-guided biopsies. Results: Clinical indications for biopsy were to histologically verify the aetiology of metabolically active bone lesions without a morphological correlate confirming the suspicion of metastases in 15 patients, to determine the origin of suspected metastases in 3 patients and to evaluate the appropriateness of targeted therapy options in 2 patients. Biopsies were technically successful in all patients. In 19 of 20 patients a definite histological diagnosis was possible. No complications or adverse effects occurred. The result of PET/CT-guided bone biopsies determined a change of the planned treatment in overall 56% of patients, with intramodality changes, e.g. chemotherapy with palliative instead of curative intent, and intermodality changes, e.g. systemic therapy instead of surgery, in 22 and 50%, respectively. Conclusion: PET/CT-guided bone biopsies are a promising alternative to conventional techniques to make metabolically active bone lesions—especially without a distinctive morphological correlate—accessible for histological verification. PET/CT-guided biopsies had a major clinical impact in patients who otherwise cannot be reliably stage grouped at the time of treatment decision

Association of proteomic markers with nutritional risk and response to nutritional support: A secondary pilot study of the EFFORT trial using an untargeted proteomics approach

Background: By means of a structured nutritional support intervention, EFFORT showed a risk reduction for adverse events in medical in-patients. We were interested in the prognostic and therapeutic potential of an untargeted proteomics approach to understand response to nutritional support, risk of 30-day mortality, and distinct patterns in severity of malnutrition risk as assessed by the Nutritional Risk screening (NRS 2002), respectively. Methods: From 2,088 patients, we randomly took 120 blood samples drawn before treatment initiation on day 1 after hospital admission. Cases were selected by treatment allocation (nutritional support vs. usual nutrition), NRS 2002, and mortality at 30 days, but not on disease type. We measured proteins by untargeted liquid chromatography mass spectrometry (LC-MS/MS). Results: We found 242 distinct proteins in 120 patients of which 81 (67.5%) survived until day 30. Between group analysis revealed a slight difference between the treatment groups in patients with a NRS 3, but not in those with a higher NRS. C-statistic between non-survivors and survivors at day 30 ranged from 0.60 (95% confidence interval 0.34-0.78) for a combination of 3 proteins/predictors to 0.65 (95% CI 0.53-0.78) for a combination of 32 proteins/predictors. In nutritional support non-survivors, pathway analysis found significant enrichment in pathways for signal transduction, platelet function, immune system regulation, extracellular matrix organization, and integrin cell surface interactions compared to survivors. Conclusion: Within this pilot study using an untargeted proteomics approach, there was only little prognostic and therapeutic potential of proteomics for phenotyping the risk of malnutrition and response to nutritional therapy. The small sample size and high heterogeneity of our population regarding comorbidity burden calls for more targeted approaches in more homogenous populations to understand the true potential of proteomics for individualizing nutritional care. Trial registration: This is a pre-planned secondary analysis of the EFFORT trial (ClinicalTrials.gov NCT02517476)

Mechanical competence of bone-implant systems can accurately be determined by image-based micro-finite element analyses

The precise failure mechanisms of bone implants are still incompletely understood. Micro-computed tomography in combination with finite element analysis appears to be a potent methodology to determine the mechanical stability of bone-implant constructs. To assess this microstructural finite element (μFE) analysis approach, pull-out tests were designed and conducted on ten sheep vertebral bodies into which orthopedic screws were inserted.μFE models of the same bone-implant constructs were then built and solved, using a large-scale linear FE-solver.μFE calculated pull-out strength correlated highly with the experimentally measured pull-out strength (r 2= 0.87) thereby statistically supporting theμFE approach. These results suggest that bone-implant constructs can be analyzed usingμFE in a detailed and unprecedented way. This could potentially facilitate the development of future implant designs leading to novel and improved fracture fixation method