• KIPS Transactions on Software and Data Engineering
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• v.8 no.8
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• pp.331-342
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• 2019

This paper proposes a method to generate test cases and test scripts from software requirements written in a controlled natural language, which helps develop reliable embedded software. In the proposed method, natural language requirements are written in a controlled language, the requirements are parsed and then inputs, outputs and operator data are extracted from the requirements. Test cases are generated from the extracted data following test case generation strategies such as decision coverage, condition coverage or modified condition/decision coverage. And then the test scripts, physical inputs of the test cases are generated with help of the test command dictionary. With the proposed method, it becomes possible to directly check whether software properly satisfies the requirements. Effectiveness of the proposed method is verified empirically with an requirement set.

• Geomechanics and Engineering
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• v.17 no.6
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• pp.565-572
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• 2019

Spatial variability is an inherent characteristic of soil, and auto-correlation length (ACL) is a very important parameter in the reliability or probabilistic analyses of geotechnical engineering that consider the spatial variability of soils. Current methods for estimating the ACL need a large amount of laboratory or in-situ experiments, which is a great obstacle to the application of random field theory to geotechnical reliability analysis and design. To estimate the ACL reasonably and efficiently, we propose a micro-structure based numerical simulation method. The quartet structure generation set algorithm is used to generate stochastic numerical micro-structure of soils, and scanning electron microscope test of soil samples combined with digital image processing technique is adopted to obtain parameters needed in the QSGS algorithm. Then, 2-point correlation function is adopted to calculate the ACL based on the generated numerical micro-structure of soils. Results of a case study shows that the ACL can be estimated efficiently using the proposed method. Sensitivity analysis demonstrates that the ACL will become stable with the increase of mesh density and model size. A model size of $300{\times}300$ with a grid size of $1{\times}1$ is suitable for the calculation of the ACL of clayey soils.

• Journal of KIISE
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• v.44 no.12
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• pp.1307-1312
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• 2017

Due to their convergence with state-of-the-art ICT technologies, the complexity and reliability demands of industrial automation systems have been rapidly increasing. In recent years, to cope with these demands, several research works have been carried out to adopt formal methods to the application development cycle at the early design stage. In this paper, we propose an automated code generation framework for industrial automation applications, based on a timed automata model. As a case study, we developed a formal model for a traffic light control system and verified the timing properties described in the specification. We finally demonstrated that the operation of a test-bed based on the auto-generated native code was identical to that of the model specification.

• Tribology and Lubricants
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• v.40 no.1
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• pp.1-7
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• 2024

Ball bearings are a major component of mechanical parts for transmitting rotation. Compared to tapered roller bearings, ball bearings offer less rolling resistance, which leads to reduced heat generation during operation. Because of these characteristics, ball bearings are widely used in electric vehicles and machine tools. The design of ball bearing cages has recently emerged as a major issue in ball bearing design. Cage design requires pre-verification of performance using theoretical or experimental formula or computational fluid dynamics (CFD). However, CFD analysis is time-consuming, making it difficult to apply in case studies for design decisions and is mainly used in performance prediction following design confirmation. To use CFD in the early stages of design, main-taining analytical accuracy while reducing the time required for analysis are necessary. Accordingly, this study proposes a laminar steady-state segment CFD technique to solve the problem of long CFD analytical times and to enable the use of CFD analysis in the early stages of design. To verify the reliability of the CFD analysis, a bearing drag torque test is performed, and the results are compared with the analytical results. The proposed laminar steady-state segment CFD technique is expected to be useful for case studies in bearing design, including cage design.