• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.2
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• pp.247-254
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• 2003

The paper presents the influence of spring dynamics and friction on dynamic responses in a spring-driven cam system. The characteristics of the friction on the camshaft are analyzed using the nonlinear pendulum experiment while the parameters of the friction model are estimated using the optimization technique. The analysis reveals that the friction of the camshaft depends on stick-slip, Stribeck effect and viscous damping. Spring elements are found to have much influence on the dynamic characteristics. Hence, they are modeled as four-degree-of-freedom lumped masses with equivalent springs. The appropriateness of the derived friction model and spring model is verified by its application to a vacuum circuit breaker mechanism of the cam-follower type.

• Asia pacific journal of information systems
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• v.9 no.1
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• pp.115-142
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• 1999

Legacy applications are valuable assets that should be integrated into next generation business systems. To gain this advantage, progressive companies can reverse engineer the legacy business operations. This paper presents a form-driven object-oriented reverse engineering(FORE) methodology by the use of business forms to recover semantics of legacy applications. They retain the user-oriented contents of business and thus are easily understandable. Our form driven object-oriented reverse engineering methodology consists of five phases: form and usage analysis, form object slicing, object structure modeling, scenario design, and model integration. Knowledge about form structure and user interaction with legacy applications is used to capture the design semantics. An object model, which consists of an object structure model and scenario results from such form knowledge. The resulting object model is more likely to help reverse engineers understand and reuse legacy systems.

• Journal of Sensor Science and Technology
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• v.32 no.6
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• pp.475-480
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• 2023

When modeling a sensor system mathematically, we assume that the sensor noise is Gaussian and white to simplify the model. If this assumption fails, the performance of the sensor model-based controller or estimator degrades due to incorrect modeling. In practice, non-Gaussian or non-white noise sources often arise in many digital sensor systems. Additionally, the noise parameters of the sensor model are not known in advance without additional noise statistical information. Moreover, disturbances or high nonlinearities often cause unknown sensor modeling errors. To estimate the uncertain noise and model parameters of a sensor system, this paper proposes an iterative batch calibration method using data-driven machine learning. Our simulation results validate the calibration performance of the proposed approach.

• Journal of Biomedical Engineering Research
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• v.39 no.2
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• pp.103-108
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• 2018

This study reviews the common-mode noise model of indirect-contact ECG measurement which uses capacitive electrode and capacitive ground, and shows the reason of the large common-mode noise in indirect-contact ECG. And then, this study shows driven-right-leg ground in indirect-contact ECG measurement, and reviews how the driven-right-leg ground reduces the common-mode noise. This study then analyzes the relation between the effective area of the indirect-contact ground and the gain of the driven-right-leg circuit. This study introduces the output voltage saturation of the driven-right-leg circuit, which occurs frequently in indirect-contact ECG measurement with the condition of the high ground impedance. This study then shows the effect of the driven-right-leg circuit saturation on the common-mode noise.

• Journal of the Institute of Convergence Signal Processing
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• v.8 no.4
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• pp.272-278
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• 2007

In this paper, we present an automated API translator for embedded software development based on a model-driven approach. Since MDA(Model Driven Architecture) provides little support for the development of embedded software, we propose a new method which contains the MDA's advantage, automation of implement process, and can solve the problem of real-time overhead. First, we define 'generic APIs' which do not depend on any RTOS's but provide most of typical RTOS services. We can describe RTOS-related behaviors of target application using these generic APIs in a CIC(Common Intermediate Code). Then, we propose a transformation tool for translating a CIC using generic APIs into a C-code for specific RTOS. The proposed API translator converts them into C-code using XML transformation rule which is defined outside. It indicates that an API translator extends to other RTOS's by modifying or adding the transformation rule. From the experiment, we validate the proposed method.

• Journal of the Korea Society for Simulation
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• v.33 no.3
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• pp.1-11
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• 2024

There are various methods to evaluate performance of a internal combustion engine. However, there have been several limitations for each methods. In this study, to overcome such limitations of a previous method, a data-driven model and physics based model linked simulation model is developed. The representative components of turbocharged engine which participate in running loop of an engine are sorted out. Sorted out components are modeled either by data-driven method or by physics based method. The engine simulator is developed by combining component model using C++ and Python. The convergence of several variables is tested to verify a simulator. Finally, as most variables has shown less than 5% error in comparison between the simulation result and the real engine test result, it is concluded that the simulator is validated. It is expected that the developed simulator could evaluate performance of various engine models with small effort. In addition, it is expected that the developed simulator would play a key role in developing an engine digital twin.

• 한국전산유체공학회:학술대회논문집
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• 2009.04a
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• pp.202-207
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• 2009

In this study, Numerical simulations were performed to analyze the characteristics of fire driven smoke flow for different location of fire source in the deeply underground subway station with using FDS code. The fire driven smoke-flow which was simulated by using Parallel Computational Method for fast calculation and LES for turbulence model. In this research, the fire location to obstruct a suitable egress from the fire disaster were discussed.

• Environmental and Resource Economics Review
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• v.14 no.4
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• pp.839-866
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• 2005

This study addresses the effects on the economy of atomic sector's R&D by considering how much KAERI's R&D expenditures in 2000 affect on the production and value-added of each industry and the whole economy. This study answers to the question using competitive import input-output tables and both supply driven and demand driven IO models, which are frequently employed in evaluating economic impacts of R&D in both domestic and foreign academic areas.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2005.05a
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• pp.97-102
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• 2005

This paper presents feed rate optimizaton of a PMLSM driven feed-slide for mininum vibrations by smoothing velocity curve with finite jerk. First of all, the PMLSM was designed and made to reduce detent force. Next, a PMLSM driven feed-slide system was mathematically modeled as a 4-degree-of-freedom lumped parameter model. The key idea of our vibration minimization method is to find out the most appropriate smooth velocity curve with finite jerk. The validity of our proposed method has been verified by comparing computer simulation results of the feed-slide model with experimental ones.

• Smart Media Journal
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• v.5 no.3
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• pp.42-48
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• 2016

Recently, most of the modern people used a second mobile device(two degree mobile device). Mobile devices are affecting all areas of human life, consumer electronics, transportation, manufacturing, and finance. On this paper, we propose a model-driven development based interaction model that can be used in the development of mobile payment system, which is the latest buzzword pins of the various application fields of mobile devices Tech (Fin-Tech) sector. Using a model-driven development based models do not depend on the Platforms (PIM), we propose a model for interaction between devices which can be reused when developing mobile billing app. A model-driven development based mobile applications use the reusable of interaction models development program analyzed the bus fees automatic payment application by a beacon.