The Experts below are selected from a list of 321 Experts worldwide ranked by ideXlab platform
Israel Gannot - One of the best experts on this subject based on the ideXlab platform.
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the effect of geometry on tumor Thermal Profile and its use in tumor functional state estimation
Journal of Biophotonics, 2015Co-Authors: Michal Tepper, Israel Gannot, Asaf ShovalAbstract:Thermal differences between transplanted tumors and tumors in humans prevent the implementation of thermographic methods developed in mice models to human models and vise-versa. Transplantable tumors tend to have an extruding shape, which may affect the Thermal patterns. This hypothesis was studied in phantom experiments and simulations. A correlation between tumor dimensions and relative temperature was found and used to estimate tumor functional state from previously published in vivo experiments. A correlation was found between temperature differences and tumor growth rates (tumor aggressiveness) and the effect of tumor treatment was demonstrated, showing the potential for in vivo, non-invasive tumor monitoring.
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Parametric study of different contributors to tumor Thermal Profile
Proceedings of SPIE, 2014Co-Authors: Michal Tepper, Israel GannotAbstract:Treating cancer is one of the major challenges of modern medicine. There is great interest in assessing tumor development in in vivo animal and human models, as well as in in vitro experiments. Existing methods are either limited by cost and availability or by their low accuracy and reproducibility. Thermography holds the potential of being a noninvasive, low-cost, irradiative and easy-to-use method for tumor monitoring. Tumors can be detected in Thermal images due to their relatively higher or lower temperature compared to the temperature of the healthy skin surrounding them. Extensive research is performed to show the validity of thermography as an efficient method for tumor detection and the possibility of extracting tumor properties from Thermal images, showing promising results. However, deducing from one type of experiment to others is difficult due to the differences in tumor properties, especially between different types of tumors or different species. There is a need in a research linking different types of tumor experiments. In this research, parametric analysis of possible contributors to tumor Thermal Profiles was performed. The effect of tumor geometric, physical and Thermal properties was studied, both independently and together, in phantom model experiments and computer simulations. Theoretical and experimental results were cross-correlated to validate the models used and increase the accuracy of simulated complex tumor models. The contribution of different parameters in various tumor scenarios was estimated and the implication of these differences on the observed Thermal Profiles was studied. The correlation between animal and human models is discussed.
Tsung-nan Tsai - One of the best experts on this subject based on the ideXlab platform.
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Thermal parameters optimization of a reflow soldering Profile in printed circuit board assembly a comparative study
Soft Computing, 2012Co-Authors: Tsung-nan TsaiAbstract:This paper presents a comparative study for optimizing the Thermal parameters of the reflow soldering process using traditional and artificial intelligence (AI) approaches. High yields in the reflow soldering process are essential to a profitable printed circuit board (PCB) assembly operation. A reflow Thermal Profile is a time-temperature graph which is used to properly control the Thermal mass and heat distribution to form robust solder joints between the PCB and electronics components during reflow soldering. An inhomogeneous temperature distribution for a reflow Thermal Profile can cause various soldering defects, which can jeopardize product reliability and lead to significant productivity loss. In the multi-objective optimization problem, three alternative optimization methods are discussed and compared: response surface methodology (RSM), nonlinear programming (NLP), and a hybrid AI technique. A dataset was gathered using a 3^8^-^4 experimental design for the development of meta-models through response surface quadratic modeling. In the first method, RSM is used to acquire the optimal heating parameters, while in the second method NLP is used to derive a global solution based on the meta-models. The back-propagation neural network (BPN) is used in the third method to formulate the nonlinear relationship between the heating inputs and responses. A genetic algorithm (GA) is then used to elicit the optimal heating parameters from the established BPN model. The evaluation results show that all three methods provide satisfactory soldering performance in terms of the process capability, sigma level, and process window indices (PWIs). Particularly, the hybrid AI approach provides superior nonlinear formulation capability and optimization performance.
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MODELING AND OPTIMIZATION OF REFLOW Thermal PROFILING OPERATION: A COMPARATIVE STUDY
Journal of The Chinese Institute of Industrial Engineers, 2009Co-Authors: Tsung-nan TsaiAbstract:ABSTRACT In this study, a comparative study of optimizing the reflow Thermal profiling parameters using a hybrid artificial intelligence and the desirability function approaches without/with combining multiple performance characteristics into a single desirability is presented. Reflow soldering is the key determinant for the improvement of the first-pass yields of electronics assembly. A reflow Thermal Profile is a time-temperature contour with multiple performance characteristics utilized to monitor the heating effects on a printed circuit board (PCB) and surface mount components (SMCs) in the reflow oven. The use of an inadequate reflow Thermal Profile may not only produce a variety of soldering failures, but can also result in the needs for considerable reworking and waste. An L18 (21*37) Taguchi experiment design is conducted to collect the Thermal profiling data. A quick propagation (QP) neural network is modeled based on experimental data to formulate the nonlinear relationship between the Thermal p...
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A neuro‐computing approach to the Thermal Profile control of the second‐side reflow process in surface mount assembly
Journal of Manufacturing Technology Management, 2005Co-Authors: Tsung-nan Tsai, Taho YangAbstract:Purpose – A neural‐network‐based predictive model is proposed to model the second‐side Thermal Profile reflow process in surface mount assembly with a view to facilitating the oven set‐up procedure and improving production yield.Design/methodology/approach – This study performs a 38−4 fractional factorial experimental twice to collect the Thermal‐Profile data from a second‐side board. The first experiment has components on the second side only, while the second experiment also has additional components on the primary side. A back‐propagation neural network (BPN) is then used to model the relationship between control variables and Thermal‐Profile measures.Findings – Empirical results illustrate the efficiency and effectiveness of the proposed BPN in solving the second‐side Thermal‐Profile prediction and control problem.Originality/value – There is no study dedicated to the investigation of the second‐side Thermal‐Profile variance with and without the presence of primary‐side components. The study suggests ...
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Neurofuzzy modelling of the reflow Thermal Profile for surface mount assembly
International Journal of Systems Science, 2005Co-Authors: Tsung-nan Tsai, Taho Yang, Pao A N HouAbstract:Troubleshooting and production set-up time are often the major contributors for productivity loss in surface mount assembly. The solder reflow process is one of the least understood process segments. The research proposes a neurofuzzy reflow Thermal Profile control system for a convection oven. An incompatible temperature Profile can result in a poor soldering quality and reduced system throughput. This paper proposes a neurofuzzy-based solder reflow Thermal Profile control system that responds to facilitate the production set-up process. The model is trained and constructed using data from both an experimental design and from historical production records. Customized computer code is used to generate a user-friendly human–machine interface and to link between neurofuzzy-reasoning rules and reflow oven set-up parameters for Thermal Profile planning and control. Empirical results illustrate the effectiveness and efficiency of the proposed system to solve a practical application.
Michal Tepper - One of the best experts on this subject based on the ideXlab platform.
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the effect of geometry on tumor Thermal Profile and its use in tumor functional state estimation
Journal of Biophotonics, 2015Co-Authors: Michal Tepper, Israel Gannot, Asaf ShovalAbstract:Thermal differences between transplanted tumors and tumors in humans prevent the implementation of thermographic methods developed in mice models to human models and vise-versa. Transplantable tumors tend to have an extruding shape, which may affect the Thermal patterns. This hypothesis was studied in phantom experiments and simulations. A correlation between tumor dimensions and relative temperature was found and used to estimate tumor functional state from previously published in vivo experiments. A correlation was found between temperature differences and tumor growth rates (tumor aggressiveness) and the effect of tumor treatment was demonstrated, showing the potential for in vivo, non-invasive tumor monitoring.
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Parametric study of different contributors to tumor Thermal Profile
Proceedings of SPIE, 2014Co-Authors: Michal Tepper, Israel GannotAbstract:Treating cancer is one of the major challenges of modern medicine. There is great interest in assessing tumor development in in vivo animal and human models, as well as in in vitro experiments. Existing methods are either limited by cost and availability or by their low accuracy and reproducibility. Thermography holds the potential of being a noninvasive, low-cost, irradiative and easy-to-use method for tumor monitoring. Tumors can be detected in Thermal images due to their relatively higher or lower temperature compared to the temperature of the healthy skin surrounding them. Extensive research is performed to show the validity of thermography as an efficient method for tumor detection and the possibility of extracting tumor properties from Thermal images, showing promising results. However, deducing from one type of experiment to others is difficult due to the differences in tumor properties, especially between different types of tumors or different species. There is a need in a research linking different types of tumor experiments. In this research, parametric analysis of possible contributors to tumor Thermal Profiles was performed. The effect of tumor geometric, physical and Thermal properties was studied, both independently and together, in phantom model experiments and computer simulations. Theoretical and experimental results were cross-correlated to validate the models used and increase the accuracy of simulated complex tumor models. The contribution of different parameters in various tumor scenarios was estimated and the implication of these differences on the observed Thermal Profiles was studied. The correlation between animal and human models is discussed.
Asaf Shoval - One of the best experts on this subject based on the ideXlab platform.
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the effect of geometry on tumor Thermal Profile and its use in tumor functional state estimation
Journal of Biophotonics, 2015Co-Authors: Michal Tepper, Israel Gannot, Asaf ShovalAbstract:Thermal differences between transplanted tumors and tumors in humans prevent the implementation of thermographic methods developed in mice models to human models and vise-versa. Transplantable tumors tend to have an extruding shape, which may affect the Thermal patterns. This hypothesis was studied in phantom experiments and simulations. A correlation between tumor dimensions and relative temperature was found and used to estimate tumor functional state from previously published in vivo experiments. A correlation was found between temperature differences and tumor growth rates (tumor aggressiveness) and the effect of tumor treatment was demonstrated, showing the potential for in vivo, non-invasive tumor monitoring.
Joseph Harrington - One of the best experts on this subject based on the ideXlab platform.
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the 1998 november 14 occultation of gsc 0622 00345 by saturn ii stratospheric Thermal Profile power spectrum and gravity waves
The Astrophysical Journal, 2010Co-Authors: Joseph Harrington, R G French, Katia I MatchevaAbstract:On 1998 November 14, Saturn and its rings occulted the star GSC 0622-00345. The occultation latitude was 55.{sup 0}5 S. This paper analyzes the 2.3 {mu}m light curve derived by Harrington and French. A fixed-baseline isoThermal fit to the light curve has a temperature of 140 {+-} 3 K, assuming a mean molecular mass of 2.35 AMU. The Thermal Profile obtained by numerical inversion is valid between 1 and 60 {mu}bar. The vertical temperature gradient is > 0.2 K km{sup -1} more stable than the adiabatic lapse rate, but it still shows the alternating-rounded-spiked features seen in many temperature gradient Profiles from other atmospheric occultations and usually attributed to breaking gravity (buoyancy) waves. We conduct a wavelet analysis of the Thermal Profile, and show that, even with our low level of noise, scintillation due to turbulence in Earth's atmosphere can produce large temperature swings in light-curve inversions. Spurious periodic features in the 'reliable' region of a wavelet amplitude spectrum can exceed 0.3 K in our data. We also show that gravity-wave model fits to noisy isoThermal light curves can lead to convincing wave 'detections'. We provide new significance tests for localized wavelet amplitudes, wave model fits, and global power spectramore » of inverted occultation light curves by assessing the effects of pre- and post-occultation noise on these parameters. Based on these tests, we detect several significant ridges and isolated peaks in wavelet amplitude, to which we fit a gravity wave model. We also strongly detect the global power spectrum of Thermal fluctuations in Saturn's atmosphere, which resembles the 'universal' (modified Desaubies) curve associated with saturated spectra of propagating gravity waves on Earth and Jupiter.« less
