This paper investigates designing all possible feedback stabilizers for Boolean control networks (BCNs). Some new results on the feedback stabilization control design of BCNs are presented. The main ...tool used in the paper is the semi-tensor product of matrices. First, the complete family of reachable sets is defined for BCNs. Then it is shown that all the complete families of reachable sets determine all possible state feedback stabilizers. Second, using all the complete families of reachable sets, all possible state feedback stabilizers are obtained. Third, a necessary and sufficient condition is obtained for the existence of output feedback stabilizers. Based on this condition, all possible output feedback stabilizers are designed for BCNs. Finally, the obtained new results are applied to the regulation of the lactose operon in Escherichia coli.
Histone post-translational modifications are crucial epigenetic mechanisms regulating a variety of biological events. Besides histone lysine acetylation, a repertoire of acylation types have been ...identified, including formylation, propionylation, butyrylation, crotonylation, 2-hydroxyisobutyrylation, β-hydroxybutyrylation, succinylation, malonylation, glutarylation and benzoylation. From a structural perspective, here we summarize the writers and erasers of histone acylations and explain the molecular basis of these enzymes catalyzing non-acetyl histone acylations with a focus on histone crotonylation and β-hydroxybutyrylation. Histone acylation readout, non-histone acylations and metabolic regulation are also discussed in this review.
17 sustainable development goals (SDGs) were committed by 193 countries in 2015. Assessing the spatio-temporal progress of achieving the SDGs can help to track the global sustainable development ...progress and identify critical development issues to eventually accelerate the achievement of SDGs. However, there is a lack of methods for the quantitative assessment of the progress of achieving SDGs at the regional level (above the national level), especially systematic methods that can simultaneously assess regions along the “Belt and Road”. To fill this research gap, after classifying 17 SDGs into four dimensions (society, economy, environment, means of implementation and cooperation), we have developed the Composite SDG Index to represent the comprehensive performance of achieving SDGs. Specifically, the index is constructed by two sub-indices, including the SDG subindex used to assess the overall performance of achieving the four dimensional SDGs and the Coupling Coordinated SDG subindex used for the first time in the SDG assessment to measure the coupling coordination degree between the four SDG dimensions. To implement this methodological framework, we chose 15 countries along the “Belt and Road” as the case study, and used 108 indicators to assess the performance of achieving SDGs for these countries. Eventually, various national development models and related policy recommendations were proposed. The three indices included in the methodological framework developed in this study can effectively enhance the global stakeholders' mutual understanding of the progress of achieving SDGs to support regional coordinated planning and national-level strategic decision-making.
Display omitted
•A composite method for assessing regional progress of achieving SDGs was successfully constructed and testified.•The coupling coordinated index was also constructed and used for the first time in the SDG assessment.•For the sample region, countries belonging to the Central and Eastern Europe had the best progress of achieving SDGs.•Three national development models and related policy recommendations were proposed.
Learning is ubiquitous in the modern scheduling environment. While the deterministic scheduling problems with known processing time and learning rate have been extensively studied, limited work ...exists to address the problems with both learning effect and uncertainty. In this paper, the single-machine scheduling problem with random nominal processing time and/or random job-based learning rate is studied, with the objective of minimizing the expected total flow time and expected makespan. Several optimal policies are obtained: first, the shortest expected processing time is optimal when only the nominal processing time is random; second, when the job-based learning rate is random, the optimal policy can be obtained by solving an assignment problem with random assignment cost. Computational study is conducted to offer insights on the behavior of optimal policy. The expected value of perfect information (EVPI) is calculated as the difference between the expected objective value found by the optimal policy, and the expected objective value with perfect information. EVPI offers a practical way for decision makers to quantify the incentive and benefit of reducing uncertainty for the addressed problem. The results show that the performance of optimal policy will be negatively impacted by high variation of random parameters.
Deep learning has achieved good performance in short-term traffic forecasting recently. However, the stochasticity and distribution imbalance are main characteristics to traffic flow, and these will ...bring the uncertainty and induce the network overfitting problem during deep learning. To deal with the problems, a new end-to-end hybrid deep learning network model, named M-B-LSTM, is proposed for short-term traffic flow forecasting in this paper. In the M-B-LSTM model, an online self-learning network is constructed as a data mapping layer to learn and equalize the traffic flow statistic distribution for reducing the effect of distribution imbalance and overfitting problem during network learning. Besides, the deep bidirectional long short-term memory network (DBLSTM) is introduced to reduce the uncertainty problem by forward and reverse contexts approximation process in the stochasticity reducing layer, and then the long short-term memory network (LSTM) is used to forecast the next traffic flow state in the forecasting layer. Furthermore, sufficient comparative experiments have been conducted and the results show the proposed model has better ability on solving uncertainty and overfitting problems than the state-of-art methods.
This paper investigates the reachability and controllability of switched Boolean control networks (BCNs) by using the semi-tensor product method. First, a kind of switching-input-state transfer graph ...is defined, based on which and the algebraic expression of switched BCNs we thus propose a new kind of switching-input-state incidence matrix that contains the complete information of the switching-input-state transfer graph. Second, by the switching-input-state incidence matrix, several necessary and sufficient conditions are obtained for the reachability and controllability of switched BCNs. Finally, an algorithm is established to find a switching sequence and a control scheme to realize the reachability of switched BCNs in the shortest time. The study of an illustrative example shows that the new results obtained in this paper are very effective in investigating the reachability and controllability of switched BCNs.
This paper investigates the output feedback stabilization of Boolean control networks (BCNs) by using the semi-tensor product method and presents a number of new results. First, based on the ...algebraic expression of BCNs, a necessary and sufficient condition is presented for the existence of output feedback stabilizers. Second, a constructive procedure is proposed to design output feedback stabilization controllers for BCNs. The study of an illustrative example shows that the new results obtained in this paper are very effective in designing output feedback stabilizers for BCNs.
This note investigates the output regulation of Boolean control networks (BCNs) by using the semi-tensor product of matrices, and presents a number of new results. Firstly, based on an algebraic ...state-space representation of BCNs, a necessary and sufficient condition is presented for the solvability of the output regulation problem. Secondly, an effective method is proposed for the control design of the output regulation problem by using an augmented system approach. The study of an illustrative example shows that the obtained new results are effective in dealing with the output regulation of BCNs.
This paper investigates the state feedback based output tracking control of Boolean control networks (BCNs) with a constant reference signal by using the semi-tensor product method. Based on the ...algebraic expression of BCNs and by constructing a series of reachable sets, a general procedure is proposed for the design of the state feedback laws for BCNs to track a constant reference signal. The study of an illustrative example shows that the obtained new results are effective in designing state feedback based output tracking controllers for BCNs to track a constant reference signal.
Eukaryotic chromosomes contain compartments of various functions, which are marked by and enriched with specific histone modifications. However, the molecular mechanisms by which these histone marks ...function in chromosome compartmentalization are poorly understood. Constitutive heterochromatin is a largely silent chromosome compartment characterized in part by H3K9me2 and 3. Here, we show that heterochromatin protein 1 (HP1), an H3K9me2 and 3 “reader,” interacts with SUV39H1, an H3K9me2 and 3 “writer,” and with TRIM28, an abundant HP1 scaffolding protein, to form complexes with increased multivalent engagement of H3K9me2 and 3-modified chromatin. H3K9me2 and 3-marked nucleosomal arrays and associated complexes undergo phase separation to form macromolecule-enriched liquid droplets. The droplets are reminiscent of heterochromatin as they are highly dense chromatin-containing structures that are resistant to DNase and exclude the general transcription factor TFIIB. Our data suggest a general mechanism by which histone marks regulate chromosome compartmentalization by promoting phase separation.
Display omitted
•HP1, SUV39H1, and TRIM28 constitute heterochromatic H3K9me3 recognition complexes•These complexes contain multiple H3K9me3 reader chromodomains•Multivalent H3K9me3-chromodomain engagement triggers liquid-liquid phase separation•Histone modifications regulate chromatin compartmentalization via phase separation
H3K9 methylation marks constitutive heterochromatin in eukaryotes. Wang et al. demonstrate that multivalent engagement of H3K9me3 by its recognition complexes drives liquid-liquid phase separation, through which constitutive heterochromatin is compartmentalized.
PDF