• International Journal of Automotive Technology
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• v.5 no.3
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• pp.145-153
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• 2004

Potential fuel economy improvements and environmental legislation have renewed interest in Gasoline Direct Injection (GDI) engines. Computational models of fuel injection and mixing processes pre-ignition are being developed for engine optimisation. These highly transient thermofluid models require verification against temporally and spatially resolved data-sets. The authors have previously established the capability of PDA to provide suitable temporally and spatially resolved spray characteristics such as mean droplet size, velocity components and qualitative mass distribution. This paper utilises this data-set to assess the predictive capability of a numerical model for GDI spray prediction. After a brief description of the two-phase model and discretisation sensitivity, the influence of initial spray conditions is discussed. A minimum of 5 initial global spray characteristics are required to model the downstream spray characteristics adequately under isothermal, atmospheric conditions. Verification of predicted transient spray characteristics such as the hollow-cone, cone collapse, head vortex, stratification and penetration are discussed, and further improvements to modelling GDI sprays proposed.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.11
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• pp.47-56
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• 2013

Rolling speed, roll gap, and cooling pattern in hot strip finishing mill process should be determined before inserting strip into roll. Such parameters are initially calculated by a mathematical set-up model. The technique to find adequate roll speed via a mathematical model has inherently limit because required working conditions are various and rolling process is nonlinear. To improve the accuracy of initial rolling speed for a finishing mill, this paper suggests a correction technology for initial rolling speed. The proposed method was implemented in hot strip mill process. As the results, the magnitude of width error in strip head-end part caused by excessive strip tension was decreased remarkably.

• Progress in Medical Physics
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• v.6 no.1
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• pp.3-11
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• 1995

A technique based on bispectrum averaging is described for generally recovering the signal waveform from a set of noisy signals with variable signal delay. The technique does not require explicit time alignment of signals and initial estimate of sigals and initial etimate of signal. The new method is suggested and is compared with other methods. This method are numerically investigated using computer generated-data and a phtsiological signal and noise. Some expermeental results for the evoked potential studies that demonstrate the technique are given. The results show the effectiveness of the technique : various potential applictions of the techique might be expected.

• 유체기계공업학회:학술대회논문집
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• 2001.11a
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• pp.235-242
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• 2001

Hydraulic performance of LCH4 fuel inducer in turbopump system was predicted by 3-D Wavier-stokes calculation. The inducer was designed initially using 1-D method. Different parameters with blade angle and flow coefficient were set from the initial design one, md computation was fulfilled to assess the redesigned models. Especially, influence of inlet back flow on inducer performance and its effective control were explored. The numerical results showed that through reducing inlet back flow strength., the hydraulic efficiency of inducer could be improved up to about $20\%$ compared to that of the initial design one.

• International Journal of CAD/CAM
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• v.6 no.1
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• pp.125-137
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• 2006

Nowadays, many commercial CAD systems support history-based, constraint-based and feature-based modeling. Unfortunately, most systems fail during the re-evaluation phase when various kind of topological changes occur. This issue is known as "persistent naming" which refers to the problem of identifying entities in an initial parametric model and matching them in the re-evaluated model. Most works in this domain focus on the persistent naming of atomic entities such as vertices, edges or faces. But very few of them consider the persistent naming of aggregates like shells (any set of faces). We propose in this paper a complete framework for identifying and matching any kind of entities based on their underlying topology, and particularly shells. The identifying method is based on the invariant structure of each class of form features (a hierarchical structure of shells) and on its topological evolution (an historical structure of faces). The matching method compares the initial and the re-evaluated topological histories, and computes two measures of topological similarity between any couple of entities occurring in both models. The naming and matching method has been implemented and integrated in a prototype of commercial CAD Software (Topsolid).

• Proceedings of the IEEK Conference
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• 2003.07e
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• pp.2104-2107
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• 2003

In this paper, we propose the method Model based Non-Rigid Moving Object Tracking. Motion based method becomes difficult to predict precisely when motion gets larger, so that we can solve such difficultly with regarding the moving object as a model. In the model based method, it should be concerned about setting initial model and updating its model in each frame. We used SNAKE in a way to set the initial model, and also proposed a modified SNAKE to handle the previous SNAKE problems. Moreover, with the elliptical setting, we made the initializing process automatically which is highly subject to change in measuring the performance of SNAKE. We used the Hausdorff distance to identify models in each frame. Through our experiments, our Proposed algorithm does effective work in Non-Rigid Moving Object Tracking.

• Korean Journal of Computational Design and Engineering
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• v.14 no.2
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• pp.105-114
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• 2009

A design needs various experience and design knowledge through a whole design process. Despite of all efforts and time, it is not easy to introduce a product that meets all customer's needs and expectation in time. To achieve the product goal, designers need a set of sequential process to find appropriate design parameters and ensure customers' needs and requirements. In this research we propose a design methodology for the initial design of an excavator front group with existing QFD(Quality Function Deployment) and Axiomatic Design to satisfy customer's requirements. It turns out that the proposed methodology can support designers more effectively, objectively, and systematically.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.17-20
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• 2012

In the RFID system, A collision occurs when the multiple tags transmit at the concurrent in slot. Reduce conflicts, in order to maximize the efficiency of the system, the number of tags with the same number of slots are allocated. the number of slots to the next frame determined by the number of contention tags. In this paper, it estimate the number of tags based on the DFSA. Analyzed the performance of the system by the initial set number of tags through simulation.

• 전기의세계
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• v.28 no.11
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• pp.45-51
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• 1979

Finte element methods are developed for the initial distribution problems which contain the surge potential circuits of high voltage transformer windings. The initial distribution of surge voltages in transformer windings are useful to the work to a practical engineering basis. However, the conventional methods of analyzing them so far are much complicated for practical designs. In this paper, the ability to solve surge potential field problems underlies the development of descreting methods to a lodal capacitive distribution-coefficients for determing the surge voltage relationship among a set of transformer coils. A practical example-the modeling of an antioscillation shield coil winding and hisercap winding is used to illustrate and evaluate these methods.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.52.1-52.1
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• 2011

We have implemented the Smoothed Particle Hydrodynamics (SPH) into the cosmological N-body simulation code. The pre-initial particle distribution is set to follow the glacial conditions and the initial temperature of hydro particles is calculated based on the adiabatic process in the expanding backgrounds. Typical adiabatic SPH equations are adopted and, additionally, non-adiabatic processes such as heating/cooling and supernova explosion are added. We study the effect of star formation criteria on the global star formation rate and compare it with the observations.