Complex continuous optimization problems widely exist nowadays due to the fast development of the economy and society. Moreover, the technologies like Internet of things, cloud computing, and big ...data also make optimization problems with more challenges including
M
any-dimensions,
M
any-changes,
M
any-optima,
M
any-constraints, and
M
any-costs. We term these as 5-M challenges that exist in large-scale optimization problems, dynamic optimization problems, multi-modal optimization problems, multi-objective optimization problems, many-objective optimization problems, constrained optimization problems, and expensive optimization problems in practical applications. The evolutionary computation (EC) algorithms are a kind of promising global optimization tools that have not only been widely applied for solving traditional optimization problems, but also have emerged booming research for solving the above-mentioned complex continuous optimization problems in recent years. In order to show how EC algorithms are promising and efficient in dealing with the 5-M complex challenges, this paper presents a comprehensive survey by proposing a novel taxonomy according to the function of the approaches, including
reducing problem difficulty
,
increasing algorithm diversity
,
accelerating convergence speed
,
reducing running time
, and
extending application field
. Moreover, some future research directions on using EC algorithms to solve complex continuous optimization problems are proposed and discussed. We believe that such a survey can draw attention, raise discussions, and inspire new ideas of EC research into complex continuous optimization problems and real-world applications.
Background and Aims
Hepatic ischemia–reperfusion injury (IRI) is a common complication of hepatectomy and liver transplantation. However, the mechanisms underlying hepatic IRI have not been fully ...elucidated. Regulator of G‐protein signaling 14 (RGS14) is a multifunctional scaffolding protein that integrates the G‐protein and mitogen‐activated protein kinase (MAPK) signaling pathways. However, the role of RGS14 in hepatic IRI remains unclear.
Approach and Results
We found that RGS14 expression increased in mice subjected to hepatic ischemia–reperfusion (IR) surgery and during hypoxia reoxygenation in hepatocytes. We constructed global RGS14 knockout (RGS14‐KO) and hepatocyte‐specific RGS14 transgenic (RGS14‐TG) mice to establish 70% hepatic IRI models. Histological hematoxylin and eosin staining, levels of alanine aminotransferase and aspartate aminotransferase, expression of inflammatory factors, and apoptosis were used to assess liver damage and function in these models. We found that RGS14 deficiency significantly aggravated IR‐induced liver injury and activated hepatic inflammatory responses and apoptosis in vivo and in vitro. Conversely, RGS14 overexpression exerted the opposite effect of the RGS14‐deficient models. Phosphorylation of TGF‐β‐activated kinase 1 (TAK1) and its downstream effectors c‐Jun N‐terminal kinase (JNK) and p38 increased in the liver tissues of RGS14‐KO mice but was repressed in those of RGS14‐TG mice. Furthermore, inhibition of TAK1 phosphorylation rescued the effect of RGS14 deficiency on JNK and p38 activation, thus blocking the inflammatory responses and apoptosis.
Conclusions
RGS14 plays a protective role in hepatic IR by inhibiting activation of the TAK1–JNK/p38 signaling pathway. This may be a potential therapeutic strategy for reducing incidences of hepatic IRI in the future.
In nature, almost every organism ages and has a limited lifespan. Aging has been explored by biologists to be an important mechanism for maintaining diversity. In a social animal colony, aging makes ...the old leader of the colony become weak, providing opportunities for the other individuals to challenge the leadership position. Inspired by this natural phenomenon, this paper transplants the aging mechanism to particle swarm optimization (PSO) and proposes a PSO with an aging leader and challengers (ALC-PSO). ALC-PSO is designed to overcome the problem of premature convergence without significantly impairing the fast-converging feature of PSO. It is characterized by assigning the leader of the swarm with a growing age and a lifespan, and allowing the other individuals to challenge the leadership when the leader becomes aged. The lifespan of the leader is adaptively tuned according to the leader's leading power. If a leader shows strong leading power, it lives longer to attract the swarm toward better positions. Otherwise, if a leader fails to improve the swarm and gets old, new particles emerge to challenge and claim the leadership, which brings in diversity. In this way, the concept "aging" in ALC-PSO actually serves as a challenging mechanism for promoting a suitable leader to lead the swarm. The algorithm is experimentally validated on 17 benchmark functions. Its high performance is confirmed by comparing with eight popular PSO variants.
Effective capture of radioactive iodine is of paramount importance for the safe and long‐term storage of fission products in the nuclear fuel cycle. Herein, a series of functionalized Th‐UiO‐66 MOFs ...was employed as a model to investigate the effects of substituents on iodine adsorption in both solution and vapor states. Sorption studies revealed that the electro‐donating amino group exhibits the most positive role on increasing the removal rate of iodine from cyclohexane and the uptake capacity of iodine vapor. Particularly, the disubstituted Th‐UiO‐66‐(NH2)2 can effectively remove 91.9 % of iodine (300 mg L−1) from cyclohexane and capture 969 mg g−1 iodine vapor, significantly higher than 59.6 % and 334 mg g−1 of untagged Th‐UiO‐66, respectively. In addition, the substituent effect on the radiolytic stability of MOFs was for the first time investigated, leading to the unearthing of one of the most radioresistant MOFs Th‐UiO‐66‐NH2 reported to date.
A systematic study on the effects of aromatic substitution on iodine adsorption was performed by employing Th‐UiO‐66 as a platform, giving rise to the disubstituted Th‐UiO‐66‐(NH2)2 with the best iodine sorption performance. Moreover, aromatic substitution was employed as a new strategy to enhance the radioresistance of MOFs.
•The Precambrian basement tectonic frameworks of the Tarim block are reconstruction.•The Tarim Block can be divided into three main tectonic units during 800–900Ma.•The unified Tarim Block should be ...more large than the present Tarim basin.
Based on new petrographic observations and zircon U–Pb geochronological data of the Precambrian basement from deep drilling cores in the Tarim basin and comparison with the Precambrian basements surrounding orogenic belts of the Tarim basin, we reconstruct a possible unified Tarim block. Data presented in this contribution lead to a three-fold subdivision of the pre-900Ma basement of the Tarim block into the North Tarim terrane, the South Tarim terrane and the Central Tarim terrane. The North Tarim terrane containing Precambrian basements of the northern part of the Tarim basin, the Korla-Kuluketage and the Dunhuang area possesses a ca. 2.7–2.5Ga or an even older continental nucleus and underwent multiple phases of magmatic and metamorphic events at ca. 2.0–1.8Ga, 1.0–0.8Ga and 760–687Ma. The South Tarim terrane including Precambrian basements of the southern part of the Tarim basin, eastern Kunlun and western Kunlun orogenic belts, possesses a 2.4–2.3Ga continental nucleus and underwent 2.0–1.75Ga and 1.0–0.8Ga metamorphic and magmatic events. The Central Tarim terrane encompassing Precambrian basement of the central part of the Tarim basin and the Altun orogenic belt, is characterized by magmatic arc system during 940–890Ma. The unified Tarim Block was assembled as part of Rodinia supercontinent after series of geological processes, e.g. (1) breakup between the North and South Tarim terranes, (2) formation of the Central Tarim ocean, (3) subduction-related magmatic arc accretion, and (4) finally amalgamation of the North and South Tarim terranes during 1.0–0.8Ga. There are two phases of the middle Neoproterozoic magmatic activities at 820–760Ma and 760–687Ma, respectively. They were most possibly related to the two phases of the Rodinia plume activities. The late Mesoproterozoic to Sinian assembly and breakup of the Rodinia led to the typical double-layered structure of the Tarim Block, i.e. the Pre-Nanhuaian basement and the Nanhuaian to Sinian cover sequence. Based on this study, we suggest that the unified Tarim Block, composed of Precambrian basement of Tarim basin and its surrounding orogenic belts, should be more large than the present Tarim basin.
Low vitamin D status is associated with progression in patients with renal cell carcinoma (RCC). The present study found that vimentin, a mesenchymal marker, was accordingly upregulated, and ...E‐cadherin, an epithelial marker, was downregulated in RCC patients with low vitamin D status. Thus, we investigated the effects of calcitriol or vitamin D3, an active form of vitamin D, on epithelial‐mesenchymal transition (EMT) in RCC cells. RCC cells were treated by two models. In model 1, three RCC cell lines, ACHN, 786‐O and CAKI‐2, were incubated with either LPS (2.0 μg/mL) or transforming growth factor (TGF)‐β1 (10 ng/mL) in the presence or absence of calcitriol (200 nmol/L). In model 2, two RCC cell lines, ACHN and CAKI‐2, were incubated with calcitriol (200 nmol/L) only. Calcitriol inhibited migration and invasion not only in TGF‐β1‐stimulated but also in TGF‐β1‐unstimulated RCC cells. Moreover, calcitriol suppressed E‐cadherin downregulation and vimentin upregulation not only in TGF‐β1‐stimulated but also in TGF‐β1‐unstimulated ACHN and CAKI‐2 cells. Calcitriol attenuated LPS‐induced upregulation of MMP‐2, MMP‐7, MMP‐9, MMP‐26 and urokinase‐type plasminogen activator (u‐PA) in ACHN cells. In addition, calcitriol blocked TGF‐β1‐induced nuclear translocation of ZEB1, Snail and Twist1 in ACHN and CAKI‐2 cells. Mechanistically, calcitriol suppressed EMT through different signaling pathways: (i) calcitriol suppressed Smad2/3 phosphorylation by reinforcing physical interaction between vitamin D receptor (VDR) and Smad3 in TGF‐β1‐stimulated RCC cells; (ii) calcitriol inhibited signal transducer and activator of transcription (STAT)3 activation in LPS‐stimulated RCC cells; (iii) calcitriol inhibited β‐catenin/TCF‐4 activation by promoting integration of VDR with β‐catenin in TGF‐β1‐unstimulated RCC cells. Taken together, calcitriol inhibits migration and invasion of RCC cells partially by suppressing Smad2/3‐, STAT3‐ and β‐catenin‐mediated EMT.
Calcitriol suppressed EMT through two different signaling pathways: (i) calcitriol suppressed Smad2/3 phosphorylation by reinforcing physical interaction between vitamin D receptor (VDR) and Smad3 in TGF‐β1‐stimulated RCC cells; (ii) calcitriol inhibited β‐catenin/TCF‐4 activation by promoting integration of VDR with β‐catenin in TGF‐β1‐unstimulated RCC cells. Taken together, calcitriol inhibits migration and invasion of RCC cells by suppressing Smad2/3‐ and β‐catenin‐mediated EMT.
Cloud workflow scheduling is a significant topic in both commercial and industrial applications. However, the growing scale of workflow has made such a scheduling problem increasingly challenging. ...Many current algorithms often deal with small- or medium-scale problems (e.g., less than 1000 tasks) and face difficulties in providing satisfactory solutions when dealing with the large-scale problems, due to the curse of dimensionality. To this aim, this article proposes a dynamic group learning distributed particle swarm optimization (DGLDPSO) for large-scale optimization and extends it for the large-scale cloud workflow scheduling. DGLDPSO is efficient for large-scale optimization due to its following two advantages. First, the entire population is divided into many groups, and these groups are coevolved by using the master-slave multigroup distributed model, forming a distributed PSO (DPSO) to enhance the algorithm diversity. Second, a dynamic group learning (DGL) strategy is adopted for DPSO to balance diversity and convergence. When applied DGLDPSO into the large-scale cloud workflow scheduling, an adaptive renumber strategy (ARS) is further developed to make solutions relate to the resource characteristic and to make the searching behavior meaningful rather than aimless. Experiments are conducted on the large-scale benchmark functions set and the large-scale cloud workflow scheduling instances to further investigate the performance of DGLDPSO. The comparison results show that DGLDPSO is better than or at least comparable to other state-of-the-art large-scale optimization algorithms and workflow scheduling algorithms.
Niching techniques have been widely incorporated into evolutionary algorithms (EAs) for solving multimodal optimization problems (MMOPs). However, most of the existing niching techniques are either ...sensitive to the niching parameters or require extra fitness evaluations (FEs) to maintain the niche detection accuracy. In this paper, we propose a new automatic niching technique based on the affinity propagation clustering (APC) and design a novel niching differential evolution (DE) algorithm, termed as automatic niching DE (ANDE), for solving MMOPs. In the proposed ANDE algorithm, APC acts as a parameter-free automatic niching method that does not need to predefine the number of clusters or the cluster size. Also, it can facilitate locating multiple peaks without extra FEs. Furthermore, the ANDE algorithm is enhanced by a contour prediction approach (CPA) and a two-level local search (TLLS) strategy. First, the CPA is a predictive search strategy. It exploits the individual distribution information in each niche to estimate the contour landscape, and then predicts the rough position of the potential peak to help accelerate the convergence speed. Second, the TLLS is a solution refine strategy to further increase the solution accuracy after the CPA roughly predicting the peaks. Compared with the other state-of-the-art DE and non-DE multimodal algorithms, even the winner of competition on multimodal optimization, the experimental results on 20 widely used benchmark functions illustrate the superiority of the proposed ANDE algorithm.
In recent years, multiobjective immune algorithms (MOIAs) have shown promising performance in solving multiobjective optimization problems (MOPs). However, basic MOIAs only use a single hypermutation ...operation to evolve individuals, which may induce some difficulties in tackling complicated MOPs. In this paper, we propose a novel hybrid evolutionary framework for MOIAs, in which the cloned individuals are divided into several subpopulations and then evolved using different evolutionary strategies. An example of this hybrid framework is implemented, in which simulated binary crossover and differential evolution with polynomial mutation are adopted. A fine-grained selection mechanism and a novel elitism sharing strategy are also adopted for performance enhancement. Various comparative experiments are conducted on 28 test MOPs and our empirical results validate the effectiveness and competitiveness of our proposed algorithm in solving MOPs of different types.
Neurotransmission requires precise control of neurotransmitter release from axon terminals. This process is regulated by glial cells; however, the underlying mechanisms are not fully understood. We ...found that glutamate release in the brain was impaired in mice lacking low-density lipoprotein receptor-related protein 4 (Lrp4), a protein that is critical for neuromuscular junction formation. Electrophysiological studies revealed compromised release probability in astrocyte-specific Lrp4 knockout mice. Lrp4 mutant astrocytes suppressed glutamatergic transmission by enhancing the release of ATP, whose level was elevated in the hippocampus of Lrp4 mutant mice. Consequently, the mutant mice were impaired in locomotor activity and spatial memory and were resistant to seizure induction. These impairments could be ameliorated by blocking the adenosine A1 receptor. The results reveal a critical role for Lrp4, in response to agrin, in modulating astrocytic ATP release and synaptic transmission. Our findings provide insight into the interaction between neurons and astrocytes for synaptic homeostasis and/or plasticity.
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