Search

Your search keyword '"Hou, Jason"' showing total 291 results
Start Over Author "Hou, Jason" Search Limiters Peer Reviewed
291 results on '"Hou, Jason"'

19. Spatial Characteristics of Colonic Mucosa-Associated Gut Microbiota in Humans

Author

Jiao, Li, Kourkoumpetis, Themistoklis, Hutchinson, Diane, Ajami, Nadim J., Hoffman, Kristi, White, Donna L., Graham, David Y., Hair, Clark, Shah, Rajesh, Kanwal, Fasiha, Jarbrink-Sehgal, Maria, Husain, Nisreen, Hernaez, Ruben, Hou, Jason, Cole, Rhonda, Velez, Maria, Ketwaroo, Gyanprakash, Kramer, Jennifer, El-Serag, Hashem B., and Petrosino, Joseph F.

Published
2022
Full Text
View/download PDF

22. Reinforcement Learning-Based Control Sequence Optimization for Advanced Reactors.

Author

Nguyen, Khang H. N., Rivas, Andy, Delipei, Gregory Kyriakos, and Hou, Jason

Subjects
REINFORCEMENT learning, NUCLEAR engineering, NUCLEAR energy, CONTROL elements (Nuclear reactors), NUCLEAR research
Abstract

The last decade has seen the development and application of data-driven methods taking off in nuclear engineering research, aiming to improve the safety and reliability of nuclear power. This work focuses on developing a reinforcement learning-based control sequence optimization framework for advanced nuclear systems, which not only aims to enhance flexible operations, promoting the economics of advanced nuclear technology, but also prioritizing safety during normal operation. At its core, the framework allows the sequence of operational actions to be learned and optimized by an agent to facilitate smooth transitions between the modes of operations (i.e., load-following), while ensuring that all safety significant system parameters remain within their respective limits. To generate dynamic system responses, facilitate control strategy development, and demonstrate the effectiveness of the framework, a simulation environment of a pebble-bed high-temperature gas-cooled reactor was utilized. The soft actor-critic algorithm was adopted to train a reinforcement learning agent, which can generate control sequences to maneuver plant power output in the range between 100% and 50% of the nameplate power through sufficient training. It was shown in the performance validation that the agent successfully generated control actions that maintained electrical output within a tight tolerance of 0.5% from the demand while satisfying all safety constraints. During the mode transition, the agent can maintain the reactor outlet temperature within ± 1.5 °C and steam pressure within 0.1 MPa of their setpoints, respectively, by dynamically adjusting control rod positions, control valve openings, and pump speeds. The results demonstrate the effectiveness of the optimization framework and the feasibility of reinforcement learning in designing control strategies for advanced reactor systems. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

24. Decreased Antibody Responses to Ad26.COV2.S Relative to SARS-CoV-2 mRNA Vaccines in Patients With Inflammatory Bowel Disease

Author

Pozdnyakova, VALERIYA, Botwin, GREGORY J., Sobhani, KIMIA, Prostko, JOHN, Braun, JONATHAN, Mcgovern, DERMOT P.B., Melmed, GIL Y., Appel, Keren, Banty, Andrea, Feldman, Edward, Ha, Christina, Kumar, Rashmi, Lee, Susie, Rabizadeh, Shervin, Stein, Theodore, Syal, Gaurav, Targan, Stephan, Vasiliauskas, Eric, Ziring, David, Debbas, Philip, Hampton, Melissa, Mengesha, Emebet, Stewart, James L., Frias, Edwin C., Cheng, Susan, Ebinger, Joseph, Figueiredo, Jane C., Boland, Brigid, Charabaty, Aline, Chiorean, Michael, Cohen, Erica, Flynn, Ann, Valentine, John, Fudman, David, Horizon, Arash, Hou, Jason, Hwang, Caroline, Lazarev, Mark, Lum, Donald, Fausel, Rebecca, Reddy, Swapna, Mattar, Mark, Metwally, Mark, Ostrov, Arthur, Parekh, Nimisha, Raffals, Laura, Sheibani, Sarah, Siegel, Corey, Wolf, Douglas, and Younes, Ziad

Published
2021
Full Text
View/download PDF

29. Cloning of ground-state intestinal stem cells from endoscopic biopsy samples

Author

Duleba, Marcin, Yamamoto, Yusuke, Neupane, Rahul, Rao, Wei, Xie, Jingzhong, Qi, Yutao, Liew, Audrey-Ann, Niroula, Suchan, Zhang, Yanting, Mahalingam, Rajasekaran, Wang, Shan, Goller, Kristina, Ajani, Jaffer A., Vincent, Matthew, Ho, Khek Yu, Hou, Jason K., Hyams, Jeffrey S., Sylvester, Francisco A., Crum, Christopher P., McKeon, Frank, and Xian, Wa

Published
2020
Full Text
View/download PDF

44. MINIMIZING CRUD DEPOSITION THROUGH OPTIMIZATION OF ASSOCIATED PARAMETERS

Author

Andersen Brian, Hou Jason, and Kropaczek Dave

Subjects
genetic algorithm, machine learning, crud, optimization, Physics, QC1-999
Abstract

A strong correlation exists between subcooled boiling in assembly subchannels and CRUD deposition. In this work a genetic algorithm is used to optimize a 17 x 17 PWR fuel assembly to have minimized subcooled boiling, minimized peak kinf, and maximized end of cycle kinf. Optimization of these parameters act as a surrogate for the optimization of CRUD deposition in fuel assemblies due to their strong correlation. Subcooled boiling, measured by vapor void in a sub channel, and values of kinf, are calculated using VERA-CS. Due to the high computational cost of VERA-CS, artificial neural networks are used as surrogate models to VERA-CS in order for the optimization to be performed in a timely manner making design work possible. Two neural networks were trained using a training library of 1200 randomly generated assembly designs and a validation library of 100 assembly designs evaluated using VERA-CS. The combination of neural networks and genetic algorithms formed an extremely fast optimization algorithm capable of evaluating designed a set of optimized pin lattices in a matter of minutes. The optimization showed a clear reduction in vapor void in the optimization solutions. This provides a proof of principle that complex phenomena requiring coupled, Multiphysics calculations, such as CRUD deposition, may be optimized.

Published
2021
Full Text
View/download PDF

45. IMPROVEMENT TO NEM SP3 MODELLING AND SIMULATION

Author

Xu Yuchao, Hou Jason, and Ivanov Kostadin N.

Subjects
nodal expansion method, simplified p3 theory, discontinuity factor, partial current, equivalence theory, Physics, QC1-999
Abstract

Accurate reactor core steady state safety analysis requires coupling between thermal-hydraulics and three dimensional multigroup pin by pin neutronics. Concerning the neutronics modeling, the Nodal Expansion Method (NEM) code is developed at North Carolina State University in the framework of high fidelity multiphysics coupling with CTF. NEM includes a simplified third-order Spherical Harmonic (SP3) solver. In this work, the solver has been improved by incorporating higher order scattering matrix library. The boundary conditions were corrected with one dimensional P3 theory and a consistent coupling coupling between zeroth- and second-order flux moments was established. Two methods for generating second order discontinuity factors (DFs) has ben developed, one based on the Generalized Equivalence Theory (GET) and one based on Parial Current Equivalence Theory (PCET). DFs were generated with three lattice sizes: single pin, 2 pins and assembly level. These developments were tested using the C5G7 benchmark. The results of the SP3 solver improvement, by using P2 and P3 scattering cross sections, show a 50% decrease in the eigenvalue (keff) prediction error compared to the reference transport solution. The GET DFs are applied in the C5G7 core pin by pin calculation and are compared with PCET DFs. The results show that PCET have a better performance in global results (eigenvalue). Concerning the different lattice sizes studies, the results show that DFs generated in smalll colorsets can improve local solutions. However, in order to reveal strong global trends, DFs should be generated in a larger corloset representative of the whole core. For the core calculations, DFs generated with the three colorsets together with an additional mixed type DFs were tested. For the mixed type, DFs generated from assembly size lattice were used for the internal interfaces and DFs generated from 2 pins size lattice were used for the assemblies boundary interfaces. These mixed DFs outperformed all the other configurations indicating that they manage to accomplish a satisfying compromise between global and local trends.

Published
2021
Full Text
View/download PDF

46. IMPLEMENTATION AND COMPARISON OF LATTICE MODULE AND DISCONTINUITY FACTORS MODULE IN PROTEUS TOOLSETS

Author

Ni Kan, Hou Jason, and Avramova Maria

Subjects
discontinuity factor, proteus, nodal method, neams, Physics, QC1-999
Abstract

State-of-the-art core nodal diffusion calculation involves the use of assembly discontinuity factor (ADF) to improve computational accuracy by introducing degree of freedom describing the relationship between interfacial discontinuities in nodal calculation [1]. The form of ADF known as the Flux based ADF (FDF) generated from flux information is recommended in the conventional two-level core calculation scheme. The multi-group cross-sections were generated using SCALE 6.2 NEWT and verified with KENO-VI [2]. A lattice module has been created for the high-fidelity neutron transport code MOCEX [3] to generate the group constants and side-independent ADFs. This new capability is verified against the reference code SCALE 6.2 NEWT under both serial and parallel modes. The implementation of ADF is performed in this work and further verified by comparing core keff. The calculation results show that the newly implemented ADF module consistently improved the accuracy of the PROTEUS-NODAL (NODAL) diffusion solver, which will become an affordable candidate for the following research of High-to-Low (Hi2Lo) transport-to-diffusion informing scheme [4].

Published
2021
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results