• 한국지능시스템학회논문지
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• 제12권6호
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• pp.577-582
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• 2002

Neural network can be trained to approximate an arbitrary nonlinear function of multivariate data like the mini-mill crown values in Automatic Shape Control. The trained weights of neural network can evaluate or generalize the process data outside the training vectors. Sometimes, the blind modeling of the process data is necessary to compare with the scattered analytical model of mini-mill process in isolated electro-mechanical forms. To come up with a viable model, we propose the blind neural-based range-division domain-clustering piecewise-linear modeling scheme. The basic ideas are: 1) dividing the range of target data, 2) clustering the corresponding input space vectors, 3)training the neural network with clustered prototypes to smooth out the convergence and 4) solving the resulting matrix equations with a pseudo-inverse to alleviate the ill-conditioning problem. The simulation results support the effectiveness of the proposed scheme and it opens a new way to the data analysis technique. By the comparison with the statistical regression, it is evident that the proposed scheme obtains better modeling error uniformity and reduces the magnitudes of errors considerably. Approximatly 10-fold better performance results.

• 한국자동차공학회논문집
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• 제6권6호
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• pp.1-6
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• 1998

A leaf spring plays an important role in a passenger bus. Since characteristic of a leaf spring has a hysteresis behaviour, modeling technique for a leaf spring is an important issue for passenger bus analysis. In this paper, modeling technique for a leaf spring is presented. First, non-linear FEM model of a leaf spring is constructed then it is used to make an approximated model to be used in dynamic analysis. The modeling procedure is ex-plained in step by step approach. Then, this model is applied to dynamic analysis of a mini-bus with flexible body and non-linear dynamic force element. The results are compared with test data.

• 산업공학
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• 제12권1호
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• pp.150-157
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• 1999

Mini-Mill process has been recently in operation at Pohang steel company, which enables more flexible steel coil production on customer demands. The effects of process parameters in Mini-Mill process need to be analyzed not only to make the process stable but also to improve product quality. This work aims to develop a regression model of Mini-Mill process using accumulated product data such that the process parameter effects on product tensile strength may be analyzed. The analysis shows that tensile strength is influenced mainly by the amount of components such as carbon, manganese, silicon, and sulfur. The effect of temperature is shown to be small. It is concluded that control of the components is much more responsible for both meeting the target and reducing the variation of the product tensile strength. Heat treatment is more useful in compensating tensile strength variations due to thickness differences and improving workability and other quality characteristics. More work is necessary for establishing regression expressions of the process that is reliable and accurate enough to dispense with the off-line inspection of the product tensile strength.

• 한국화재소방학회논문지
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• 제23권5호
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• pp.84-89
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• 2009

본 연구에서는 미분무수 노즐을 이용하여 소화시간에 영향을 미치는 인자들을 변화시키며 소화실험을 수행하였다. 주요 인자는 화염의 위치와 노즐 중심으로부터의 거리, 미분무 입자의 크기, 노즐의 설치 높이, 개구부 여부 등이었다. 소화실험 결과로부터 각 인자들 간의 상호작용과 소화에 대한 민감도를 Mini tab을 이용하여 분석하여 미분무수 소화시스템의 최적 소화모델을 도출하였다. 소화시간에 가장 큰 영향을 미치는 인자는 노즐 중심으로부터의 거리이며 개구부의 여부는 다른 인자들에 비하여 소화시간에 미치는 영향도가 적게 나타났다.

• Journal of information and communication convergence engineering
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• 제1권1호
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• pp.6-11
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• 2003

In general, standard TCP/IP (transmission control protocol-internet protocol), which is called TCP/IP, is using as the communication basis protocol between any collections of networks that is connected. In this paper, using this TCP/IP implementation of remote control system and suitable program for long distance communication is proposed. This system can make system, which basic Ethernet and TCP/IP used system, to mini modeling, so all module that is using here can be used. Therefore, intention of this paper is to reduce expenses, to effective manage for plant and to increase of productivity as linking each plant of several factory to TCP/IP and Ethernet, and then many control plant and manager minimize the needed course.

• Nuclear Engineering and Technology
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• 제30권6호
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• pp.496-506
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• 1998

This paper deals with the computational modeling of buoyancy-driven turbulent heat transfer involving spatially uniform volumetric heat sources in semicircular geometry. The Launder & Sharma low-Reynolds number k-$\varepsilon$ turbulence model without any modifications and the SIMPLER computational algorithm were used for the numerical modeling, which was incorporated into the new computer code CORE-TNC. This computer code was subsequently benchmarked with the Mini-ACOPO experimental data in the modified Rayleigh number range of 2$\times$10$^{13}$ $\times$10$^{14}$ . The general trends of the velocity and temperature fields were well predicted by the model used, and the calculated isotherm patterns were found to be very similiar to those observed in previous experimental investigations. The deviation between the Mini-ACOPO experimental data and the corresponding numerical results obtained with CORE-TNC for the average Nusselt number was less than 30% using fine grid in the near-wall region and the three-point difference formula for the wall temperature gradient. With isothermal pool boundaries, heat was convected predominantly to the upper and adjacent lateral surfaces, and the bottom surface received smaller heat fluxes.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년도 12th Asian Congress of Fluid Mechanics
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• pp.28.3-28.3
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• 2008

• Journal of Smart Tourism
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• 제1권2호
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• pp.37-46
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• 2021

The travel-related applications on a smartphone help tourists make a reservation before their trip conveniently; use a map, direction guidance, and translation services during the travel; evaluate and recommend travel services communicating with others after their journey. This study examines the relationships among affordances and constraints provided by the mini-program, users' perceived value, and travel-related mini-program (TRMP) usage by analyzing the structural equation modeling. An online questionnaire was developed from the available scales in the published literature. A total of 651 TRMP users responded to the survey, and 448 valid responses were included for analysis. Affordance, including physical, cognitive, sensory, and functional affordance, significantly influenced the hedonic value of TRMP; utilitarian value except for cognitive affordance. There were negative relationships between unfamiliarity and both types of value. The utilitarian and hedonic value of TRMP significantly influenced both the exploitative and explorative use of TRMP. Travel-related mobile applications are dramatically increased in the tourism field. This research sheds light on TRMP usage, as a new and smart device, from a user's perspective based on the affordance theory. This study represents a valuable direction regarding the emerging travel-related online platforms in tourism.

• The Korean Journal of Physiology and Pharmacology
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• 제20권5호
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• pp.507-514
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• 2016

Although 3D-complex fractionated atrial electrogram (CFAE) mapping is useful in radiofrequency catheter ablation for persistent atrial fibrillation (AF), the directions and configuration of the bipolar electrodes may affect the electrogram. This study aimed to compare the spatial reproducibility of CFAE by changing the catheter orientations and electrode distance in an in -silico left atrium (LA). We conducted this study by importing the heart CT image of a patient with AF into a 3D-homogeneous human LA model. Electrogram morphology, CFAE-cycle lengths (CLs) were compared for 16 different orientations of a virtual bipolar conventional catheter (conv-cath: size 3.5 mm, inter-electrode distance 4.75 mm). Additionally, the spatial correlations of CFAE-CLs and the percentage of consistent sites with CFAE-CL<120 ms were analyzed. The results from the conv-cath were compared with that obtained using a mini catheter (mini-cath: size 1 mm, inter-electrode distance 2.5 mm). Depending on the catheter orientation, the electrogram morphology and CFAE-CLs varied (conv-cath: $11.5{\pm}0.7%$ variation, mini-cath: $7.1{\pm}1.2%$ variation), however the mini-cath produced less variation of CFAE-CL than conv-cath (p<0.001). There were moderate spatial correlations among CFAE-CL measured at 16 orientations (conv-cath: $r=0.3055{\pm}0.2194$ vs. mini-cath: $0.6074{\pm}0.0733$, p<0.001). Additionally, the ratio of consistent CFAE sites was higher for mini catheter than conventional one ($38.3{\pm}4.6%$ vs. $22.3{\pm}1.4%$, p<0.05). Electrograms and CFAE distribution are affected by catheter orientation and electrode configuration in the in-silico LA model. However, there was moderate spatial consistency of CFAE areas, and narrowly spaced bipolar catheters were less influenced by catheter direction than conventional catheters.

• International Journal of Aeronautical and Space Sciences
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• 제10권2호
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• pp.148-160
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• 2009

By the development of recent technology, a new variant of rotorcrafts having four rotors start drawing attention from aerial-robotics engineers more than before. Its potential spans from just being control device test bed to performing difficult task such as carrying surveillance device to unreachable places. In this regards, modeling a quad-rotor is significant in analyzing its dynamic behavior and in synthesizing control system for such a vehicle. This paper summarizes the modeling of a mini quad-rotor aerial vehicle. A first principle approach is considered for deriving the model based on Euler-Newton equations of motion. The result of the modeling is a simulation platform that is expected to acceptably predict the dynamic behavior of the quad-rotor in various flight conditions. Linear models associated with different flight condition can be extracted for the purpose of control synthesis.