Browsing by Subject "network"

Now showing 1 - 7 of 7

An Efficient Switch Model for Simulating Large Power Systems with Many Power Converters
(0000-00-00) Uriarte, F. M.; Mashayekh, S.
Frequent matrix factorizations due to power electronic switch commutations are computationally expensive. This paper addresses this burden by treating power electronic switches as dependant sources instead of time-varying resistors. The resulting network matrix is constant, and does not require re-factorization when switches commutate. Three power electronic switches are presented and discussed for both nodal and mesh equation formulations. A case study at the end shows that the run-time for a power system with >200 switches when using the switching approach presented herein can reduce from 8 hours to under 15 minutes, which is a speedup of 40x.
How to Strengthen Your Network
(2021-02-22) Simon, Jeremy M.
Network Builders
(2017-06-15) Simon, Jeremy M.; Todd Savage
Network Flow Modeling of Multireservoir Distribution Systems
(University of Texas at Austin, 1974-06) Jensen, P.A.; Bhaumik, G.; Driscoll, W.
Network Flow Optimization for Water Resources Planning with Uncertainties in Supply and Demand
(University of Texas at Austin, 1980-07) Jensen, P.A.; Chu, H.W.; Cochard, D.D.
The Safety Net as a Network
(RGK Center Working Paper, Summer Fellowship Program, 2007) Liu, Helen K.
The lack of a coherent understanding of what is meant by the American safety net made it difficult to have a meaningful discourse on the current condition. This paper proposes an alternative formulation of the social safety net based in network theory to overcome the shortcomings of the previous literature. The first part of the paper describes this approach, attempting to develop an alternative understanding of the safety net grounded in the actions of anti-poverty actors. Next is a list of propositions for measuring five dimensions of a safety net: the frame, structure, positions, influences, and the context. Three policy implications are derived from this new paradigm. First, shifting the level of analysis to network level allows policy makers to broaden the scope of the modern social safety net. Second, quantifying the interaction among actors reveals interdependency, which in turn redefines the power and influence of each actor within the network. Finally, the modern safety net could demonstrate a core-periphery structure. It calls for a new way of thinking about resource distribution and decision making channels of such unique structure.
Tgif1 Counterbalances The Activity Of Core Pluripotency Factors In Mouse Embryonic Stem Cells
(2015-10) Lee, Bum-Kyu; Shen, Wenwen; Lee, Jiwoon; Rhee, Catherine; Chung, Haewon; Kim, Kun-Yong; Park, In-Hyun; Kim, Jonghwan; Lee, Bum-Kyu; Shen, Wenwen; Lee, Jiwoon; Rhee, Catherine; Chung, Haewon; Kim, Jonghwan
Core pluripotency factors, such as Oct4, Sox2, and Nanog, play important roles in maintaining embryonic stem cell (ESC) identity by autoregulatory feedforward loops. Nevertheless, the mechanism that provides precise control of the levels of the ESC core factors without indefinite amplification has remained elusive. Here, we report the direct repression of core pluripotency factors by Tgif1, a previously known terminal repressor of TGF beta/activin/nodal signaling. Overexpression of Tgif1 reduces the levels of ESC core factors, whereas its depletion leads to the induction of the pluripotency factors. We confirm the existence of physical associations between Tgif1 and Oct4, Nanog, and HDAC1/2 and further show the level of Tgif1 is not significantly altered by treatment with an activator/inhibitor of the TGF beta/activin/nodal signaling. Collectively, our findings establish Tgif1 as an integral member of the core regulatory circuitry of mouse ESCs that counterbalances the levels of the core pluripotency factors in a TGF beta/activin/nodal-independent manner.