A model of state aggregation

2020 ◽  
Author(s):  
Anastasia Burkovskaya
Keyword(s):  
State Aggregation

scholarly journals Influence of Solution-State Aggregation on Conjugated Polymer Crystallization in Thin Films and Microwire Crystals

Giant ◽  
2021 ◽  
pp. 100064
Author(s):  
Yu-Qing Zheng ◽  
Ze-Fan Yao ◽  
Jin-Hu Dou ◽  
Yilin Wang ◽  
Wei Ma ◽  
...  
Keyword(s):  
Thin Films ◽  
Conjugated Polymer ◽  
Polymer Crystallization ◽  
Solution State ◽  
State Aggregation

scholarly journals Proportional lumpability and proportional bisimilarity

2021 ◽  
Author(s):  
Andrea Marin ◽  
Carla Piazza ◽  
Sabina Rossi
Keyword(s):  
Markov Chain ◽  
Markov Chains ◽  
Upper And Lower Bounds ◽  
General Definition ◽  
Performance Indices ◽  
State Aggregation ◽  
Structural Regularity ◽  
Original Definition ◽  
Aggregation Technique ◽  
Definition Of

AbstractIn this paper, we deal with the lumpability approach to cope with the state space explosion problem inherent to the computation of the stationary performance indices of large stochastic models. The lumpability method is based on a state aggregation technique and applies to Markov chains exhibiting some structural regularity. Moreover, it allows one to efficiently compute the exact values of the stationary performance indices when the model is actually lumpable. The notion of quasi-lumpability is based on the idea that a Markov chain can be altered by relatively small perturbations of the transition rates in such a way that the new resulting Markov chain is lumpable. In this case, only upper and lower bounds on the performance indices can be derived. Here, we introduce a novel notion of quasi-lumpability, named proportional lumpability, which extends the original definition of lumpability but, differently from the general definition of quasi-lumpability, it allows one to derive exact stationary performance indices for the original process. We then introduce the notion of proportional bisimilarity for the terms of the performance process algebra PEPA. Proportional bisimilarity induces a proportional lumpability on the underlying continuous-time Markov chains. Finally, we prove some compositionality results and show the applicability of our theory through examples.

scholarly journals Emergent behaviors of discrete Lohe aggregation flows

2022 ◽  
Vol 0 (0) ◽  
pp. 0
Author(s):  
Hyungjun Choi ◽  
Seung-Yeal Ha ◽  
Hansol Park
Keyword(s):  
Matrix Model ◽  
Unit Sphere ◽  
Splitting Method ◽  
Discrete Models ◽  
Asymptotic State ◽  
Sphere Model ◽  
State Aggregation ◽  
Strang Splitting ◽  
Complete State ◽  
Emergent Behaviors

<p style='text-indent:20px;'>The Lohe sphere model and the Lohe matrix model are prototype continuous aggregation models on the unit sphere and the unitary group, respectively. These models have been extensively investigated in recent literature. In this paper, we propose several discrete counterparts for the continuous Lohe type aggregation models and study their emergent behaviors using the Lyapunov function method. For suitable discretization of the Lohe sphere model, we employ a scheme consisting of two steps. In the first step, we solve the first-order forward Euler scheme, and in the second step, we project the intermediate state onto the unit sphere. For this discrete model, we present a sufficient framework leading to the complete state aggregation in terms of system parameters and initial data. For the discretization of the Lohe matrix model, we use the Lie group integrator method, Lie-Trotter splitting method and Strang splitting method to propose three discrete models. For these models, we also provide several analytical frameworks leading to complete state aggregation and asymptotic state-locking.</p>

scholarly journals A Study of Soil Factors in Relation to Erosion and Land Use on a Nigeria Soil.

2019 ◽  
pp. 17-20
Author(s):  
Ufinomue O.E ◽  
Ehis-Iyoha E.
Keyword(s):  
Land Use ◽  
Aggregate Stability ◽  
Soil Productivity ◽  
Soil Factors ◽  
Mean Values ◽  
Virgin Forest ◽  
State Aggregation ◽  
Mean Weight Diameter ◽  
History Of ◽  
Forest Soil Organic Matter

An assessment of the effects of erosion on the soil productivity of Agbor area of Delta State, Southern Nigeria was evaluated. The investigation involved three (3) soils (Virgin forest, Arable cropping and Traffic soils) with history of erosion. The aggregate stability, mean weight diameter (MWD) and state aggregation of soil of the area was studied, since these soils properties have direct relationship with soil erodibility. The results reveals that the soil texture was loamy sand. mean weight diameter values ranged from 0.56 mm (Traffic), 0.74 mm (arable cropping) and 1.25 mm (virgin forest). State of aggregation ranged from 12.00 mm (arable cropping), 23.00 mm (traffic) and 43.3 mm (virgin forest). Mean porosity 65.4 mm (traffic soils), 72.1 mm (arable cropping) and 77.0 mm (virgin forest). Mean aggregate stability ranged from 74.4 mm (traffic soils), 25.8 mm (arable cropping) and 48.00 mm (virgin forest). Soil organic matter mean values ranged from 0.08 g/ kg (traffic soils), 1.90 g/ kg (arable cropping) and 2.72 g/ kg (virgin forest), respectively. The results recorded for virgin forest relative to arable cropping and traffic soils in most of the soil properties evaluated is an indi- cation that current land use practices in Agbor area contribute immensely to the accelerated soil degradation observed in the area.

Potential aggregation hot spots in recombinant human keratinocyte growth factor; a computational study

2020 ◽  
Author(s):  
Mansoureh Shahbazi Dastjerdeh ◽  
Mohammad Ali Shokrgozar ◽  
Hamzeh Rahimi ◽  
Majid Golkar
Keyword(s):  
Growth Factor ◽  
Tertiary Structure ◽  
Computational Study ◽  
Keratinocyte Growth Factor ◽  
Native State ◽  
Hydrophobic Residues ◽  
Aggregation Propensity ◽  
State Aggregation ◽  
Human Keratinocyte ◽  
Aggregation Tendency

Abstract Background: Recombinant human keratinocyte growth factor is a highly aggregation-prone therapeutic protein. The high aggregation liability of rhKGF is manifested by loss of the monomeric form of the protein and accumulation of the aggregated species even at moderate temperatures. Here, we analyzed rhKGF for its vulnerability towards aggregation by detection of aggregation-prone regions (APRs) using several sequence-based computational tools including TANGO, SolubiS, ZipperDB, AGGRESCAN, Zyggregator, Camsol, PASTA, SALSA, WALTZ, SODA, Amylpred, AMYPDB, and structure-based tools including Aggrescan3D and molecular dynamics-based spatial aggregation propensity (SAP) algorithm. Results: The sequence-based prediction of APRs in rhKGF indicated that they are mainly located at positions 10-30, 40-60, 61-66, 88-120, and 130-140 which are rich in β-branched aliphatic, hydrophobic, aromatic and Glutamine/Aspargine (Q/N) residues. Mapping on the rhKGF tertiary structure revealed that most of these residues including F16-R25, I43, E45, R47-I56, F61, Y62, N66, L88-E91, E108-F110, A112, N114, T131, and H133-T140 are surface-exposed in the natively folded protein which can promote aggregation without major unfolding event or the conformational change may occur in the oligomers composed of natively folded monomers. The other regions are buried in the native state and their contribution to non-native aggregation is mediated by a preceding unfolding event in the monomeric state of the protein. The structure-based prediction of APRs using SAP tool limited the number of identified APRs to the dynamically-exposed hydrophobic residues including V12, A50, V51, L88, I89, L90, I118, L135, and I139 mediating the native-state aggregation. Conclusion: Our analysis of APRs in rhKGF identified the regions determining the intrinsic aggregation propensity in both folded (native) and unfolded state of the protein. These regions are the candidate positions for engineering the rhKGF sequence to reduce its aggregation tendency.

State aggregation and discrete-state Markov chains embedded in a class of point processes

1995 ◽  
Vol 32 (01) ◽  
pp. 39-51
Author(s):  
Xi-Ren Cao
Keyword(s):  
Markov Chains ◽  
Poisson Process ◽  
Point Process ◽  
Point Processes ◽  
Marked Point ◽  
Practical Importance ◽  
Marked Point Process ◽  
Interarrival Time ◽  
Discrete State ◽  
State Aggregation

One result that is of both theoretical and practical importance regarding point processes is the method of thinning. The basic idea of this method is that under some conditions, there exists an embedded Poisson process in any point process such that all its arrival points form a sub-sequence of the Poisson process. We extend this result by showing that on the embedded Poisson process of a uni- or multi-variable marked point process in which interarrival time distributions may depend on the marks, one can define a Markov chain with a discrete state that characterizes the stage of the interarrival times. This implies that one can construct embedded Markov chains with countable state spaces for the state processes of many practical systems that can be modeled by such point processes.

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