• Communications of the Korean Mathematical Society
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• v.36 no.1
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• pp.11-18
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• 2021

In this article, we deal with Zariski topology on graded comultiplication modules. The purpose of this article is obtaining some connections between algebraic properties of graded comultiplication modules and topological properties of dual Zariski topology on graded comultiplication modules.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.11
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• pp.2365-2373
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• 2012

To obtain Korea AS-level internet topology, we used three data sources, which include BGP data of UCLA IRL, IRR and IXP data. Using Internet topology generator models(Waxman, BA and GLP), we developed three graphs that have same number of nodes as Korea AS-level Internet. Then we compared each graph with the Korea AS-level Internet topology. Through this study we could find that the existing Internet topology generators can't simulate Korea AS-level internet.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.6
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• pp.113-122
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• 2003

Topology optimization is begun with layout optimization that is attributed to Rozvany and Prager of the 1960's. They claimed that structure was transformed into truss connecting all the nodes of finite element and optimized by control of its sectional modulus. But, this method is partial topology optimization. General layout optimal design appliable to continum structure was proposed by Bendsoe and Kikuchi in 1988. Topology optimization expresses material stiffness of structure into function of arbitrary variable. If this variable is 1, material exists but if this variable is 0, material doesn't exist. Therefore, topology optimization searches the distribution function of material stiffness for structure. There are a few researchs for simple engineering problem such as topology optimization of square plane structure or truss structure. So, This study applied to topology optimization of table liner for vertical roller mill that is the largest scale in the world. After table liner decreased by 20% of original weight, the structure analysis for first optimized model was performed.

• Journal of Power Electronics
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• v.17 no.6
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• pp.1694-1706
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• 2017

Models and experiments for magnetic resonance coupling wireless power transmission (MRC-WPT) topologies such as the chain topology and branch topology are studied in this paper. Coupling mode theory based energy resonance models are built for the two topologies. Complete energy resonance models including input items, loss coefficients, and coupling coefficients are built for the two topologies. The storage and the oscillation model of the resonant energy are built in the time domain. The effect of the excitation item, loss item, and coupling coefficients on MRC systems are provided in detail. By solving the energy oscillation time domain model, distance enhancing models are established for the chain topology, and energy relocating models are established for the branch topology. Under the assumption that there are no couplings between every other coil or between loads, the maximum transmission capacity conditions are found for the chain topology, and energy distribution models are established for the branch topology. A MRC-WPT experiment was carried out for the verification of the above model. The maximum transmission distance enhancement condition for the chain topology, and the energy allocation model for the branch topology were verified by experiments.

• East Asian mathematical journal
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• v.35 no.2
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• pp.239-257
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• 2019

The purpose of this study is to show that the topology is closely related to some subjects learned in school mathematics and then to give motivations for learning of the topology. To do this, it is showed that the topology is an abstracted device that deal with structure of limit and continuity introduced in school mathematics. This study took a literature study. The results of this study are as follows. First, the formal definition of general topology to structure open sets was examined. The nearness relation together with the closure operation was introduced and used to characterize for construction of general topology. Second, as definitions for continuity of function, we considered the intuitive definition, definition, structured definitions using open intervals and definition using open sets and then we investigated their roles. We also examined equivalent definition using the nearness relation which is helpful to understand continuity of function. Third, the sequence and its limit are treated in terms of continuous functions having the set of natural numbers and its extended set as domains. From these, it can be concluded that the convergence of sequence and the continuity of function are identified as functions that preserve the nearness relation and that the topology is a specialized tool for dealing with convergence and continuity.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.4
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• pp.100-106
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• 2022

Topology optimization is applied for the optimal design of various products to ensure weight reduction and productivity improvement. Reducing the weight of the mold while maintaining its rigidity can ensure shortening of the production cycle, stabilization of the mold temperature, and reduction of mold material costs. In this study, a topology optimization technique was applied to the optimal design of the injection mold, and a topology-optimized model of the mold was obtained. First, the injection mold for the square specimens was modeled. Subsequently, a structural analysis was performed by implementing a load condition generated during the injection molding process. Topology optimization was performed based on the structural analysis results, and the models of the initial and topology-optimized designs were manufactured at 1/4 magnification using a 3D printer. Consequently, compared with the existing model, the weight of the topology-optimized model decreased by 9.8%, and the manufacturing time decreased by 7.61%.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.6
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• pp.259-267
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• 2002

In this paper, we focus on comparison and analysis of performance for existing Topology Aggregation algorithm. For these, we designed and implemented PNNI routing simulator which contain various TA schemes, and evaluate performance of TA schemes by this simulator. The PNNI 1.0 specification of the ATM Forum is recommended that hierarchical routing protocol and topology information is aggregated in the network constructed hierarchically Aggregating topology information is known as TA(Topology Aggregation) and TA is very important for scalability and security in network. Therefore, the performance of PNNI network would vary with TA schemes and routing algorithm. PNNI routing simulator can be applied to develope Routing algorithm and TA algorithm and can be develope these algorithms in short period.

• Steel and Composite Structures
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• v.27 no.1
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• pp.27-33
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• 2018

In this study, a mixed-interpolated tensorial component 4 nodes method (MITC4) is treated as a numerical analysis model for topology optimization using multiple materials assigned within Reissner-Mindlin plates. Multi-material optimal topology and shape are produced as alternative plate retrofit designs to provide reasonable material assignments based on stress distributions. Element density distribution contours of mixing multiple material densities are linked to Solid Isotropic Material with Penalization (SIMP) as a design model. Mathematical formulation of multi-material topology optimization problem solving minimum compliance is an alternating active-phase algorithm with the Gauss-Seidel version as an optimization model of optimality criteria. Numerical examples illustrate the reliability and accuracy of the present design method for multi-material topology optimization with Reissner-Mindlin plates using MITC4 elements and steel materials.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.11
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• pp.57-62
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• 2010

The transmission case has bearing loads, The case should be designed with more stiffness and lightweight under high external loads, In this study, we performed FEA(Finite Element Analysis) for the transmission case and performed topology optimization base on the results of FEA. We performed topology optimization with the control of the shape size which is the results of topology optimization and suggested the shaped of the transmission case of topology optimization.

• Journal of applied mathematics & informatics
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• v.28 no.1_2
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• pp.99-107
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• 2010

This paper is a study about the relationships among topologies and intuitionistic fuzzy topology induced, respectively, by approximation operators and an intuitionistic fuzzy approximation operator associated with an approximation space (X, R), when the relation R on X is precisely reflexive and transitive. In particular, we consider an intuitionistic fuzzy approximation operator on an approximation space X (i.e., a set X with a reflexive and transitive relation on it), which turns out to be an intuitionistic fuzzy closure operator. This intuitionistic fuzzy closure operator gives rise to two saturated fuzzy topologies on X and it turns out that all the level topologies of one of the fuzzy topology coincide and equal to the topology analogously induced on X by a crisp approximation operator. These observations are then applied to intuitionistic fuzzy automata.