16 results on '"Tyler Holt"'
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2. Optimal Power Flow With State Estimation in the Loop for Distribution Networks
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Guo, Yi, primary, Zhou, Xinyang, additional, Zhao, Changhong, additional, Chen, Lijun, additional, and Summers, Tyler Holt, additional
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- 2023
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3. An Online Joint Optimization–Estimation Architecture for Distribution Networks
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Yi Guo, Xinyang Zhou, Changhong Zhao, Lijun Chen, Gabriela Hug, and Tyler Holt Summers
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Control and Systems Engineering ,Electrical and Electronic Engineering - Published
- 2023
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4. Analyzing Reading Assessments through a Randomized Trial
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Anne M. Cizmar and Benjamin Tyler Holt
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Sociology and Political Science ,Education - Published
- 2022
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5. Optimal Pump Control for Water Distribution Networks via Data-Based Distributional Robustness
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Guo, Yi, primary, Wang, Shen, additional, Taha, Ahmad F., additional, and Summers, Tyler Holt, additional
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- 2023
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6. Sparse Structure Design for Stochastic Linear Systems via a Linear Matrix Inequality Approach
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Guo, Yi, Stanojev, Ognjen, Hug, Gabriela, and Summers, Tyler Holt
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We propose a sparsity-promoting feedback control design for stochastic linear systems with multiplicative noise. The objective is to identify an optimal sparse control architecture and optimize the closed-loop performance while stabilizing the system in the mean-square sense. Our approach approximates the nonconvex combinatorial optimization problem by minimizing various matrix norms subject to the linear matrix inequality (LMI) stability condition. We present two design problems to reduce the number of actuators and the number of sensors via a low-dimensional output. A regularized linear quadratic regulator with multiplicative (LQRm) noise optimal control problem and its convex relaxation are presented to demonstrate the tradeoff between the suboptimal closed-loop performance and the sparsity degree of control structure. Case studies on power grids for wide-area frequency control show that the proposed sparsity-promoting control can considerably reduce the number of sensors and actuators without significant loss in system performance. The sparse control architecture is robust to substantial system-level disturbances while achieving mean-square stability.
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- 2024
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7. The clinical KRAS(G12C) inhibitor AMG 510 drives anti-tumour immunity
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Timothy J. Price, Victor J. Cee, Tisha San Miguel, Gerald Steven Falchook, Jonathan Werner, Christopher Mohr, Tao Osgood, James Kuo, Kevin Gaida, Xiaochun Zhu, Karen Rex, John D. McCarter, Brian A. Lanman, H. Henary, Roberto Ortiz, Ramaswamy Govindan, Tara Arvedson, Laurie P. Volak, Wenjun Ouyang, J. Russell Lipford, Tyler Holt, Charles G. Knutson, Neelima Koppada, David S. Hong, Aaron S. Rapaport, Anne Y. Saiki, Bert H. O'Neil, Jude Canon, Ji Rong Sun, Marwan Fakih, Brett E. Houk, Dhanashri Bagal, Keegan Cooke, and Jayesh Desai
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0301 basic medicine ,Chemotherapy ,Multidisciplinary ,Oncogene ,business.industry ,medicine.medical_treatment ,Cancer ,medicine.disease_cause ,medicine.disease ,Acquired immune system ,Clinical trial ,03 medical and health sciences ,030104 developmental biology ,0302 clinical medicine ,Antigen ,030220 oncology & carcinogenesis ,Cancer cell ,Cancer research ,Medicine ,KRAS ,business - Abstract
KRAS is the most frequently mutated oncogene in cancer and encodes a key signalling protein in tumours1,2. The KRAS(G12C) mutant has a cysteine residue that has been exploited to design covalent inhibitors that have promising preclinical activity3–5. Here we optimized a series of inhibitors, using novel binding interactions to markedly enhance their potency and selectivity. Our efforts have led to the discovery of AMG 510, which is, to our knowledge, the first KRAS(G12C) inhibitor in clinical development. In preclinical analyses, treatment with AMG 510 led to the regression of KRASG12C tumours and improved the anti-tumour efficacy of chemotherapy and targeted agents. In immune-competent mice, treatment with AMG 510 resulted in a pro-inflammatory tumour microenvironment and produced durable cures alone as well as in combination with immune-checkpoint inhibitors. Cured mice rejected the growth of isogenic KRASG12D tumours, which suggests adaptive immunity against shared antigens. Furthermore, in clinical trials, AMG 510 demonstrated anti-tumour activity in the first dosing cohorts and represents a potentially transformative therapy for patients for whom effective treatments are lacking. Treatment of KRASG12C-mutant cancer cells with the KRAS(G12C) inhibitor AMG 510 leads to durable response in mice, and anti-tumour activity in patients suggests that AMG 510 could be effective in patients for whom treatments are currently lacking.
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- 2019
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8. Optimal Power Flow with State Estimation In the Loop for Distribution Networks
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Yi Guo, Xinyang Zhou, Changhong Zhao, Lijun Chen, and Tyler Holt Summers
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Control and Systems Engineering ,Computer Networks and Communications ,Optimization and Control (math.OC) ,FOS: Mathematics ,FOS: Electrical engineering, electronic engineering, information engineering ,Systems and Control (eess.SY) ,Electrical and Electronic Engineering ,Mathematics - Optimization and Control ,Electrical Engineering and Systems Science - Systems and Control ,Computer Science Applications ,Information Systems - Abstract
We propose a framework for integrating optimal power flow (OPF) with state estimation (SE) in the loop for distribution networks. Our approach combines a primal-dual gradient-based OPF solver with a SE feedback loop based on a limited set of sensors for system monitoring, instead of assuming exact knowledge of all states. The estimation algorithm reduces uncertainty on unmeasured grid states based on a few appropriate online state measurements and noisy "pseudo-measurements". We analyze the convergence of the proposed algorithm and quantify the statistical estimation errors based on a weighted least squares (WLS) estimator. The numerical results on a 4521-node network demonstrate that this approach can scale to extremely large networks and provide robustness to both large pseudo measurement variability and inherent sensor measurement noise., Comment: arXiv admin note: text overlap with arXiv:1909.12763
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- 2020
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9. Optimal Pump Control for Water Distribution Networks via Data-based Distributional Robustness
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Yi Guo, Shen Wang, Ahmad F. Taha, and Tyler Holt Summers
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Control and Systems Engineering ,Optimization and Control (math.OC) ,FOS: Mathematics ,FOS: Electrical engineering, electronic engineering, information engineering ,Systems and Control (eess.SY) ,Electrical and Electronic Engineering ,Mathematics - Optimization and Control ,Electrical Engineering and Systems Science - Systems and Control - Abstract
In this paper, we propose a data-based methodology to solve a multi-period stochastic optimal water flow (OWF) problem for water distribution networks (WDNs). The framework explicitly considers the pump schedule and water network head level with limited information of demand forecast errors for an extended period simulation. The objective is to determine the optimal feedback decisions of network-connected components, such as nominal pump schedules and tank head levels and reserve policies, which specify device reactions to forecast errors for accommodation of fluctuating water demand. Instead of assuming the uncertainties across the water network are generated by a prescribed certain distribution, we consider ambiguity sets of distributions centered at an empirical distribution, which is based directly on a finite training data set. We use a distance-based ambiguity set with the Wasserstein metric to quantify the distance between the real unknown data-generating distribution and the empirical distribution. This allows our multi-period OWF framework to trade off system performance and inherent sampling errors in the training dataset. Case studies on a three-tank water distribution network systematically illustrate the tradeoff between pump operational cost, risks of constraint violation, and out-of-sample performance.
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- 2020
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10. Abstract 1057: Combination of the KRASG12C inhibitor sotorasib with targeted agents improves anti-tumor efficacy in KRAS p.G12C cancer models
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Victor J. Cee, Alla Verlinsky, Anne Y. Saiki, Brian A. Lanman, Marwan Fakih, J. Russell Lipford, Tyler Holt, Patricia McElroy, Karen Rex, Ji-Rong Sun, Jude Canon, Tao Osgood, Upendra P. Dahal, and Bernd Bruenner
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Antitumor activity ,Cancer Research ,Oncology ,business.industry ,Cancer research ,Medicine ,business - Abstract
KRAS is the most frequently mutated oncogene in cancer and encodes a key signaling protein in tumors. The p.G12C mutation of KRAS is present in approximately 13% of lung adenocarcinoma, 3% of colorectal cancer, and 2% of other solid tumors. Sotorasib (formerly known as AMG 510), the first KRASG12C inhibitor to reach clinical testing in humans, has demonstrated evidence of clinical activity as a single agent in patients with non-small cell lung (NSCLC), colorectal (CRC), endometrial, and appendiceal carcinoma. Preclinically, sotorasib has shown significant tumor growth inhibition as a single agent in multiple CDX and PDX models. The clinically-validated strategy of combining multiple inhibitors in the MAPK pathway suggests that combination strategies could yield even better outcomes for patients. Specifically, the combination of sotorasib and other inhibitors in the MAPK and AKT signaling pathways might further enhance tumor cell killing and overcome potential resistance. To test this hypothesis, in vitro combination experiments were conducted in multiple KRAS p.G12C cell lines with combination matrices of sotorasib and inhibitors of HER kinases, EGFR, SOS1, SHP2, MEK, PI3K, or mTOR, as well as an inhibitor of cyclin-dependent kinases 4 and 6 (CDK4/6). The combination of sotorasib with multiple agents resulted in robust synergistic cell killing of KRAS p.G12C tumor cells in vitro. To understand whether these observations translated in vivo, we assessed combinations of sotorasib with a SHP-2 inhibitor or a HER kinase inhibitor in pharmacodynamic assays and efficacy models in tumor xenografts. Consistent with the synergy observed in vitro, sotorasib in combination with a HER kinase inhibitor (afatinib) or a SHP2 inhibitor (RMC-4550) in vivo resulted in enhanced inhibition of MAPK signaling as measured by p-ERK in NCI-H358 tumors. In efficacy studies using the NCI-H358 xenograft model, significantly enhanced anti-tumor activity was observed with a minimally efficacious dose of sotorasib in combination with afatinib, RMC-4550, or a CDK4/6 inhibitor (palbociclib). Furthermore, enhanced anti-tumor activity was observed with sotorasib in combination with a MEK inhibitor or with the anti-EGFR monoclonal antibody panitumumab in a CRC KRAS p.G12C PDX model. Taken together, these data support the clinical evaluation of combination treatment of sotorasib with analogous agents in patients with KRAS p.G12C tumors. Citation Format: Karen Rex, Anne Y. Saiki, Tyler Holt, Alla Verlinsky, Patricia L. McElroy, Tao Osgood, Ji-Rong Sun, Marwan G. Fakih, Upendra P. Dahal, Bernd Bruenner, Victor J. Cee, Brian A. Lanman, Jude Canon, J. Russell Lipford. Combination of the KRASG12C inhibitor sotorasib with targeted agents improves anti-tumor efficacy in KRAS p.G12C cancer models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1057.
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- 2021
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11. Data-Based Distributionally Robust Stochastic Optimal Power Flow—Part II: Case Studies
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Guo, Yi, primary, Baker, Kyri, additional, Dall'Anese, Emiliano, additional, Hu, Zechun, additional, and Summers, Tyler Holt, additional
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- 2019
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12. Data-Based Distributionally Robust Stochastic Optimal Power Flow—Part I: Methodologies
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Guo, Yi, primary, Baker, Kyri, additional, Dall'Anese, Emiliano, additional, Hu, Zechun, additional, and Summers, Tyler Holt, additional
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- 2019
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13. Abstract 3090: In vivo characterization of AMG 510 - a potent and selective KRASG12Ccovalent small molecule inhibitor in preclinical KRASG12Ccancer models
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Victor J. Cee, Laurie P. Volak, Brian A. Lanman, Karen Rex, Robert S. Foti, Neelima Koppada, Ji-Rong Sun, Jude Canon, J. Russell Lipford, Tyler Holt, and Anne Y. Saiki
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0301 basic medicine ,Cancer Research ,Mutation ,Colorectal cancer ,Chemistry ,Wild type ,Cancer ,medicine.disease ,medicine.disease_cause ,03 medical and health sciences ,030104 developmental biology ,0302 clinical medicine ,Oncology ,In vivo ,Cell culture ,030220 oncology & carcinogenesis ,Cancer research ,medicine ,Adenocarcinoma ,KRAS - Abstract
Somatic activating mutations of RAS family members are tumor driver mutations found in an estimated 21% of all cancers. Oncogenic KRAS mutations at residues G12, G13, and Q61 represent the most common RAS mutations found in solid malignancies. The prevalence of KRAS p.G12C tumors is ~13% of lung adenocarcinoma (including NSCLC), 3% of colorectal carcinoma (CRC), and 1% to 2% of numerous other solid tumors, representing an unmet medical need. We have developed AMG 510, an orally bioavailable, covalent inhibitor of KRASG12C with potent biochemical and cellular activity, and robust in vivo efficacy. AMG 510 inhibited SOS-catalyzed nucleotide exchange of recombinant mutant KRASG12C/C118A but had minimal effect on KRASC118A, which is wildtype at position 12. In cellular assays, AMG 510 covalently modified KRASG12C and inhibited KRASG12C signaling as measured by phosphorylation of ERK1/2 (p-ERK) in all KRAS p.G12C-mutant cell lines tested but did not inhibit p-ERK in cell lines with various other KRAS mutations. AMG 510 also selectively impaired viability of KRAS p.G12C mutant cell lines but did not affect cell lines with other KRAS mutations. In vivo pharmacodynamic assays demonstrated dose- and time-dependent inhibition of KRASG12Csignaling in human pancreatic and NSCLC tumor xenografts. Covalent modification of KRASG12C by AMG 510 was measured by mass spectrometry and correlated with p-ERK inhibition in tumors. AMG 510 significantly inhibited the growth of KRAS p.G12C xenografts and resulted in tumor regression. Combination treatment of AMG 510 with standard-of-care and targeted agents demonstrated enhanced tumor growth inhibition compared to either single agent. In a syngeneic model of KRAS p.G12C mutant cancer, AMG 510 treatment significantly inhibited tumor growth and caused regression. AMG 510 is currently in Phase 1, first-in-human clinical trials for patients with advanced solid tumors harboring a KRAS p.G12C mutation. Citation Format: Karen Rex, Anne Y. Saiki, Ji-Rong Sun, Tyler Holt, Neelima Koppada, Brian A. Lanman, Laurie P. Volak, Robert S. Foti, Victor J. Cee, J. Russell Lipford, Jude Canon. In vivo characterization of AMG 510 - a potent and selective KRASG12Ccovalent small molecule inhibitor in preclinical KRASG12Ccancer models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3090.
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- 2019
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14. Skin extracellular matrix stimulation following injection of a hyaluronic acid-based dermal filler in a rat model
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Thomas Kim, Xiaojian Sun, Tyler Holt, Sumit Paliwal, Darin J. Messina, Steven Fagien, Christopher K. Hee, and Dennis E. Van Epps
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Injections, Intradermal ,Stimulation ,Biocompatible Materials ,Enzyme-Linked Immunosorbent Assay ,Dermal Fillers ,Collagen Type I ,Extracellular matrix ,Rats, Sprague-Dawley ,Collagen Type III ,chemistry.chemical_compound ,Gene expression ,Hyaluronic acid ,Medicine ,Animals ,Hyaluronic Acid ,Skin ,biology ,business.industry ,Reverse Transcriptase Polymerase Chain Reaction ,Molecular biology ,Elastin ,Extracellular Matrix ,Rats ,chemistry ,biology.protein ,Surgery ,business ,Homeostasis ,Biomarkers - Abstract
Background Hyaluronic acid-based dermal fillers have gained rapid acceptance for treating facial wrinkles and deep tissue folds. Although their space-filling properties are well understood, this study evaluates the cellular and molecular changes in skin, as a secondary effect, following injection of a commercially available, 24-mg/ml, cross-linked hyaluronic acid-based filler (HYC-24L+) in a rodent model. Methods Sprague-Dawley rats, aged 2 to 4 months, were injected intradermally with 20 μl of HYC-24L+ using a linear threading technique and followed to 12 weeks after injection. Untreated skin and saline injection were used as study controls. Enzyme-linked immunosorbent assay and reverse-transcriptase polymerase chain reaction methods were used to investigate changes in the expression of several extracellular matrix proteins and genes over time. Results HYC-24L+ significantly increased the protein expression levels of collagen types I and III in rat dermal tissue for up to 12 weeks. The ratio of collagen type III to type I protein, however, remained unchanged, suggesting maintenance of collagen homeostasis. A significant increase in dermal elastin after HYC-24L+ injection was also observed. Gene expression analysis confirmed that several genes associated with extracellular matrix production and assembly were also transiently up-regulated, and that these changes temporally preceded those observed at the protein level. Conclusion In addition to its well-understood space-filling function, as a secondary effect, the authors demonstrate that HYC-24L+ stimulates the production of several extracellular matrix components, including dermal collagen and elastin.
- Published
- 2014
15. Case report of an oral fibroma occurring in a patient with familial multiple lipomas
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Lida, Radfar, Tyler, Holt, and Farah, Masood
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Diagnosis, Differential ,Family Health ,Neoplasms, Multiple Primary ,Skin Neoplasms ,Dental Care for Chronically Ill ,Anticoagulants ,Humans ,Female ,Mouth Neoplasms ,Fibroma ,Lipoma ,Glucocorticoids ,Aged - Abstract
A wide variety of lesions may manifest in the oral soft tissues that could be confusing and challenging for the clinicians. These lesions could be as simple as trauma-induced ulcers that need about 2 weeks to heal, to a more complicated situation such as oral cancer. The key points in developing diagnosis and a possible treatment plan may include a comprehensive oral examination, simple understanding of normal oral tissue features, and knowledge of common oral lesions. This will help in the development of a differential diagnosis of the oral lesions/masses based on the risk factors in that particular patient. In this case report, we present a simple oral mass in a patient who had an oral fibroma and lipomas in other areas.
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- 2014
16. Cooperative shape and orientation control of autonomous vehicle formations
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Summers, Tyler Holt
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- Cooperative control, Autonomous vehicle formations, Rigid graph theory, Spectral graph theory
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This dissertation solves variations of three mathematical problems for autonomous vehicle formations: (1) formation shape control in the plane, (2) robust information architecture design, and (3) formation attitude synchronization. An autonomous vehicle formation is a collection of vehicles, each with computation, communication, sensing, and control capabilities, that cooperate to achieve a common objective. Accelerating advancements are making possible a range of science and engineering applications, such as satellite formations for deep-space imaging, teams of unmanned aircraft for military reconnaissance and surveillance missions, and submarine swarms for oceanic exploration. The ubiquitous potential of these applications is driving theoretical work on autonomous vehicle formations across a range of disciplines. A major theoretical question in the field of control theory, and the main focus of this dissertation, is how the properties of the information architecture (i.e. a mapping of the information flow amongst the agents), relate to the stability properties of the desired shape and orientation under certain control laws. A secondary focus is how to design the information flow so that loss of an agent does not destroy the formation's ability to maintain a desired shape. As a motivating example, a solution to a coordinated standoff tracking problem is presented to demonstrate how an instance of a class of information architectures, which are called persistent and related to rigid graph theory, can be used to achieve a formation objective in a practical scenario involving a team of unmanned aircraft. A generalized formation shape control problem is then solved for a class of persistent architectures. This solution gives only local stability results; global stability is analyzed for a four-agent formation and several open problems are identified. The problem of agent loss is addressed by performing a self-repair operation in the event of agent loss and separately by designing robustness into the information architecture a priori. Finally, a rigid body attitude synchronization problem with communication time delays is solved for a class of information architectures based on spectral graph theory.
- Published
- 2010
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