• Nuclear Engineering and Technology
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• v.54 no.10
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• pp.3864-3877
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• 2022

We propose a new approach called PESA (Prioritized replay Evolutionary and Swarm Algorithms) combining prioritized replay of reinforcement learning with hybrid evolutionary algorithms. PESA hybridizes different evolutionary and swarm algorithms such as particle swarm optimization, evolution strategies, simulated annealing, and differential evolution, with a modular approach to account for other algorithms. PESA hybridizes three algorithms by storing their solutions in a shared replay memory, then applying prioritized replay to redistribute data between the integral algorithms in frequent form based on their fitness and priority values, which significantly enhances sample diversity and algorithm exploration. Additionally, greedy replay is used implicitly to improve PESA exploitation close to the end of evolution. PESA features in balancing exploration and exploitation during search and the parallel computing result in an agnostic excellent performance over a wide range of experiments and problems presented in this work. PESA also shows very good scalability with number of processors in solving an expensive problem of optimizing nuclear fuel in nuclear power plants. PESA's competitive performance and modularity over all experiments allow it to join the family of evolutionary algorithms as a new hybrid algorithm; unleashing the power of parallel computing for expensive optimization.

• Geomechanics and Engineering
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• v.33 no.6
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• pp.597-609
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• 2023

The instability and failure of engineered rock masses are influenced by crack initiation and propagation. Uniaxial compression and acoustic emission (AE) experiments were conducted on cracked sandstone. The effect of the crack's dip on the crack initiation was investigated using fracture mechanics. The crack propagation was investigated based on stress-strain curves, AE multi-parameter characteristics, and failure modes. The results show that the crack initiation occurs at the tip of the pre-fabricated crack, and the crack initiation angle increases from 0° to 70° as the dip angle increases from 0° to 90°. The fracture strength k_cr is derived varies in a U-shaped pattern as β increased, and the superior crack angle β_m is between 36.2 and 36.6 and is influenced by the properties of the rock and the crack surface. Low-strength, large-scale tensile cracks form during the crack initiation in the cracked sandstone, corresponding to the start of the AE energy, the first decrease in the b-value, and a low r-value. When macroscopic surface cracks form in the cracked sandstone, high-strength, large-scale shear cracks form, resulting in a rapid increase in the AE energy, a second decrease in the b-value and an abrupt increase in the r-value. This research has significant theoretical implications for rock failure mechanisms and establishment of damage indicators in underground engineering.

• Animal Systematics, Evolution and Diversity
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• v.30 no.3
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• pp.183-190
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• 2014

The four species of the family Dendrophylliidae are newly recorded in Korea: Balanophyllia (Balanophyllia) cumingii Milne Edwards and Haime, 1848, Balanophyllia (Balanophyllia) vanderhorsti Cairns, 2001, Cladopsammia eguchii (Wells, 1982), and Cladopsammia gracilis (Milne Edwards and Haime, 1848). The two genera of Balanophyllia and Cladopsammia, to which the four species belong, are newly recorded in Korea. They were collected from the subtidal zones in Jeju-do Island, Korea by SCUBA diving from 1987 to 2012. This study aims to identify the four dendrophyllid species based on external and internal morphological characters including growth form, size, budding, and color of colonies, shape and size of corallites, columella, theca, and septa. Balanophyllia (Balanophyllia) cumingii is distinguished by its solitary growth form, small and low subturbinate corallite with enlarged calice, and expanded basal part, exsert first and second septa, and Pourtal$\acute{e}$s plan. Balanophyllia (Balanophyllia) vanderhorsti is characterized by its quasi-colonial growth form, subturbinate corallites with compressed calice, thick theca, and Pourtal$\acute{e}$s plan. Cladopsammia eguchii is characterized by its phaceloid growth form of compressed corallites basally united with common coenosteum, flat spongy columella, thick theca, and Pourtal$\acute{e}$s plan. Cladopsammia gracilis is distinguished by its phaceloid growth form of corallites basally united with common coenosteum, and pronounced Pourtal$\acute{e}$s plan forming flower patterns.

• International Journal of High-Rise Buildings
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• v.5 no.2
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• pp.87-94
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• 2016

High-rise as a building typology is gaining popularity in Asian mega-cities, due to its advantages in increasing volumetric density with limited land resources. Numerous factors contribute to the formation of high-rise urban form, from economical and institutional, environmental to socio-political. Environmental concerns over the impact of rapid urbanization in developing economies demand new thought on the link between urban environment and urban form. Outdoor and indoor climate, pedestrian comfort, and building energy consumption are all related to and impacted by urban form and building morphology. There are many studies and practices on designing individual "green" high-rise buildings, but far fewer studies on designing high-rise building clusters from the perspective of environmental performance optimization.. This paper focuses on the environmental perspective, and its correlation with the evolution of the high-rise urban form. Previous studies on urban morphology in terms of environmental and energy performance are reviewed. Studies on "parameterizing" urban morphology to estimate its environmental performance are reviewed, and the possible urban design implications of the study are demonstrated in by the author, by way of a microclimate map of the iconic Shanghai Xiao Lujiazui CBD. The study formulates the best-practice design guidelines for creating walkable and comfortable outdoor space in a high-rise urban setting, including proper sizing of street blocks and building footprint, provision of shading, and facilitating urban ventilation.

• Journal of Intelligence and Information Systems
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• v.12 no.3
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• pp.67-82
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• 2006

We propose the HBEM(Hybrid Behavior Evolution Model) composed of rule classification and evolutionary neural network using rule descriptor and link descriptor for evolutionary behavior of virtual robots. In our model, two levels of the knowledge of behaviors were represented. In the upper level, the representation was improved using rule and link descriptors together. And then in the lower level, behavior knowledge was represented in form of bit string and learned adapting their chromosomes by the genetic operators. A virtual robot was composed by the learned chromosome which had the best fitness. The composed virtual robot perceives the surrounding situations and they were classifying the pattern through rules and processing the result in neural network and behaving. To evaluate our proposed model, we developed HBES(Hybrid Behavior Evolution System) and adapted the problem of gathering food of the virtual robots. In the results of testing our system, the learning time was fewer than the evolution neural network of the condition which was same. And then, to evaluate the effect improving the fitness by the rules we respectively measured the fitness adapted or not about the chromosomes where the learning was completed. In the results of evaluating, if the rules were not adapted the fitness was lowered. It showed that our proposed model was better in the learning performance and more regular than the evolutionary neural network in the behavior evolution of the virtual robots.

• Journal of the Korean Ceramic Society
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• v.29 no.11
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• pp.912-918
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• 1992

Microstructure evolution including morphological change in the vicinity of the electrodes, porosity change and grain boundary migration was observed in polycrystalline CoO subject to electric fields at 1100 and 121$0^{\circ}C$ in air. At the cathode, the transported cations react with oxygen in the surrounding to form new lattices, while, at the anode, the reverse reaction occurs leading to lattice annihilation. Lattice formation also takes place at the surface of pores near the cathode inducing pore-filling effect. Grain boundary migration was found bo be enhanced or retarded depending on the field direction. It is therefore implied that the driving force of grain boundary migration is the vectorial sum of the curvature-induced chemical potential gradient and the electric field applied.

• Journal of Ecology and Environment
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• v.30 no.4
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• pp.315-318
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• 2007

Cooperative or non-territorial permanently social spiders are believed to have evolved from species showing subsocial maternal care. The transition from subsocial to cooperative social groups probably involved a transition from an outbreeding breeding system to one with inbreeding. Nepotistic recognition among siblings should facilitate the evolution of social cooperation through avoidance of inbreeding and maintenance of mutual tolerance between siblings. We conducted experiments to determine whether a mechanism for sibling recognition is present in the subsocial spider, Coelotes terrestris which displays extended maternal care in the form of food provisioning. The numbers of surviving individuals within unfed groups were observed and compared between non-sibling groups of ten spiderlings and groups of ten siblings. The number of survivors differed significantly between groups, with consistently fewer spiderlings surviving in the non-sibling groups than the sibling groups over the study period. This result suggests that sibling recognition and nepotism do occur in this subsocial species. The nepotism involved in the maternal social organization of the Coelotes might be an example of a preadaptation facilitating the evolution of permanent social life.

• The Bulletin of The Korean Astronomical Society
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• v.38 no.2
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• pp.49.2-49.2
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• 2013

We report preliminary results from a radio study of central galaxies in cool and non-cool core clusters. A cooling flow is expected to rapidly form in the center of galaxy clusters unless additional heating mechanisms such as merging with sub clusters are at work. It has been suggested that cool flows can feed the AGN in the central galaxies, increasing their power. On the other hand, the AGN feedback can also affect the surrounding medium, heating back up the gas in the cluster core region. In this study, we investigate the co-evolution of cool flows and the AGN of galaxies located in the cluster center. For this study, we have selected 13 radio bright central galaxies from clusters with a range of cooling time scale. In this work, we present results of our recent observations using the Korean VLBI Network. We discuss the properties of the sample in radio and other wavelengths.

• Journal of applied mathematics & informatics
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• v.28 no.1_2
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• pp.143-152
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• 2010

Based on the Exp-function method and a suitable transformation, new generalized solitonary solutions including free parameters of the MDI and Sawada-Kotera equations with variable coefficients are obtained, form which solitary wave solutions and periodic solutions including some known solutions reported in open literature are derived as special cases. The free parameters in the obtained generalized solitonary solutions might imply some meaningful results in the physical models. It is shown that the Exp-function method provides a very effective and important new method for nonlinear evolution equations with variable coefficients.

• Proceedings of the Technology Innovation Conference
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• 1997.07a
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• pp.124-159
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• 1997

This paper examines a significant example of accumulation of technology in post war Japan - the development process of the videocasstte recorder (VCR) for home use, and the dynamic evolution process of the mass market. The purpose of analyzing the Japanese home VCR industry is to clarify how and why only the Japanese makers had succeeded in developing home VCR and dominated. the global mass market and to make clear the dynamic process of industrial evolution. This study found out the following facts; 1) Japanese inter-firm interactions in the VCR have been carried out by the structure of "the competition and cooperation among the engaged players" form the initial stage, to growing, and maturing stage. 2) The process of competition and cooperation produced the revolutionary innovation through a continuous systematic development process in the R&D phase. 3) The process of competition and cooperation accelerated the speed of technological progress and the rapid growth of the industry in the growing and maturing stage.