• Title/Summary/Keyword: New Approach

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Aircraft Engine Performance Test Technologies by 150K lbf Thrust Test Cell (15만 파운드급 테스트 셀을 이용한 엔진성능 시험기술)

  • Kim, Woocheol;Kim, Chul;Kim, Sangbaek
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2017.05a
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    • pp.180-187
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    • 2017
  • Major design targets such as test cell type, cell flow, cell bypass ratio, approach velocity, cell depression, front cell distortion, noise level and vibration level to construct a new 150,000 lbf thrust aircraft engine test facility were established. Based on the final aerodynamic and acoustic performance tests conducted at the newly constructed test facility, it was found that the new test facility is judged to be excellent and meets design targets.

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Estimation of error variance in nonparametric regression under a finite sample using ridge regression

  • Park, Chun-Gun
    • Journal of the Korean Data and Information Science Society
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    • v.22 no.6
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    • pp.1223-1232
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    • 2011
  • Tong and Wang's estimator (2005) is a new approach to estimate the error variance using least squares method such that a simple linear regression is asymptotically derived from Rice's lag- estimator (1984). Their estimator highly depends on the setting of a regressor and weights in small sample sizes. In this article, we propose a new approach via a local quadratic approximation to set regressors in a small sample case. We estimate the error variance as the intercept using a ridge regression because the regressors have the problem of multicollinearity. From the small simulation study, the performance of our approach with some existing methods is better in small sample cases and comparable in large cases. More research is required on unequally spaced points.

A Rational Approach to the Flexural Concrete Beam Analysis with Crack Growth using Fracture Mechanic Concepts (크랙을 고려한 휨을 받는 콘크리트보의 해석)

  • Heo, Gwang Hee;Choi, Man Young
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.2 no.4
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    • pp.159-171
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    • 1998
  • This study attempts to develop a rational approach to flexural concrete beam analysis with crack growth. In order to develope analytical solutions, several simplification and assumption are made and the Hillerborg fictitious crack model is adapted for new rational approach to the flexural concrete beam. To provide desired results, the concrete beams with various conditions(more than 126 beam conditions) are analyzed. Before producing the results, these assumptions are founded to be justified by comparison with a FE analysis. The results for each condition of the beams are presented in terms of crack lengths, the strength and cracking stability of concrete beams. And also size effects in a flexural concrete beam is studied using a new flexural cracking model.

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A Study on Seam Tracking for Robotic Arc Welding Using Snapshot Visual Data (비젼 데이타를 이용한 아크 용접로보트의 용접선 추적에 관한 연구)

  • Kim, Eun-Yeob;Kim, Kwang-Soo
    • Journal of Korean Institute of Industrial Engineers
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    • v.18 no.2
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    • pp.83-97
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    • 1992
  • A new approach, to seam tracking for robotic are welding is proposed. In this approach, the weld model is a snapshot image and the acquired image is analyzed and compared to the welding database which contains CAD data, weld positions, weld parameters, etc. This paper presents a fast and robust algorithm for the Hough Transform. This modified Hough Transform(MHT) algorithm uses the least-squares regression analysis method in order to approximate the edge lines more precisely, and leads to a significant reduction in both computation and storage. In comparison with the conventional seam tracking methods, this new approach has the advantages of low cost, continuous welding, and various type welding.

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A study on the recognition performance of connected digit telephone speech for MFCC feature parameters obtained from the filter bank adapted to training speech database (훈련음성 데이터에 적응시킨 필터뱅크 기반의 MFCC 특징파라미터를 이용한 전화음성 연속숫자음의 인식성능 향상에 관한 연구)

  • Jung Sung Yun;Kim Min Sung;Son Jong Mok;Bae Keun Sung;Kang Jeom Ja
    • Proceedings of the KSPS conference
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    • 2003.05a
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    • pp.119-122
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    • 2003
  • In general, triangular shape filters are used in the filter bank when we get the MFCCs from the spectrum of speech signal. In [1], a new feature extraction approach is proposed, which uses specific filter shapes in the filter bank that are obtained from the spectrum of training speech data. In this approach, principal component analysis technique is applied to the spectrum of the training data to get the filter coefficients. In this paper, we carry out speech recognition experiments, using the new approach given in [1], for a large amount of telephone speech data, that is, the telephone speech database of Korean connected digit released by SITEC. Experimental results are discussed with our findings.

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A Geographic Information System(GIS) Approach for Modeling a Soil Erosion Map from Available Data

  • Yang, Young-Kyu;Miller, Lee-D.
    • Korean Journal of Remote Sensing
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    • v.2 no.1
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    • pp.23-33
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    • 1986
  • The Universal Soil Loss Equation (USLE) has been applied to the microcomputer based Geographic Information System (GIS) data planes to model a soil erosion map for a county. The conventional method applied by US Soil conservation Service (SCS) has been tedious and time consuming process on a mainframe computer which yields a multisectioned, hard to interprete, line printer map of the each county's soil loss. The new approach proved to be an economical and efficient tool for the natural resource managers in their decision malting in land conservation practice. They can simulate the variety of conservation practices and assess the cost and benefit without physically implementing the conservation measures.7he new approach also can produce all the other graphical and statistical reports.

A Study on a New Approach to Robust Control and Torque Control Response Analysis of Manufacturing robot Based on Monitoring Simulator for Smart Factory

  • Kim, Hee-Jin;Kim, Dong-Ho;Jang, Gi-Won;Gu, Byeong-Hwa;Han, Sung-Hyun
    • Journal of the Korean Society of Industry Convergence
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    • v.24 no.4_1
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    • pp.397-409
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    • 2021
  • This study proposes a new approach to implimentation of robust control and torque control response analysis based on monitoring simulator for smart factory. According to the physical properties of a flexible manipulator, a two time-scale approach, namely, singular perturbation ap proach, is further utilized for thorough analysis and general controller design. It is shown that asymptotic motional tracking can be effectively achieved, whereas the force regulation errors can be made arbitrarily small. For demonstration of the proposed technology performance, experiments of a eight joint flexible manipulator are performed for the proposed control method, and the reliability of proposed control results are illustrated based on monitoring simulator.

Optimal Control Approach for a Smart Grid

  • Imen Amdouni;Naziha Labiadh;Lilia El amraoui
    • International Journal of Computer Science & Network Security
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    • v.23 no.12
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    • pp.194-198
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    • 2023
  • The current electricity networks will undergo profound changes in the years to come to be able to meet the growing demand for electricity, while minimizing the costs of consumers and producers, etc. The electricity network of tomorrow or even the intelligent « Smart Grids » network will be the convergence of two networks: the electricity network and the telecommunications network. In this context falls our work which aims to study the impact of the integration of energy decentralization into the electricity network. In this sense, we have implemented a new smart grid model where several coexisting suppliers can exchange information with consumers in real time. In addition, a new approach to energy distribution optimization has been developed. The simulation results prove the effectiveness of this approach in improving energy exchange and minimizing consumer purchase costs and line losses.

A New Green Clustering Algorithm for Energy Efficiency in High-Density WLANs

  • Lu, Yang;Tan, Xuezhi;Mo, Yun;Ma, Lin
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.8 no.2
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    • pp.326-354
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    • 2014
  • In this paper, a new green clustering algorithm is proposed to be as a first approach in the framework of an energy efficient strategy for centralized enterprise high-density WLANs. Traditionally, in order to maintain the network coverage, all the APs within the WLAN have to be powered-on. Nevertheless, the new algorithm can power-off a large proportion of APs while the coverage is maintained as its always-on counterpart. The two main components of the new approach are the faster procedure based on K-means and the more accurate procedure based on Evolutionary Algorithm (EA), respectively. The two procedures are processes in parallel for different designed requirements and there is information interaction in between. In order to implement the new algorithm, EA is applied to handle the optimization of multiple objectives. Moreover, we adapt the method for selection and recombination, and then introduce a new operator for mutation. This paper also presents simulations in scenarios modeled with ray-tracing method and FDTD technique, and the results show that about 67% to 90% of energy consumption can be saved while it is able to maintain the original network coverage during periods when few users are online or the traffic load is low.

Study on evolution in smallpox therapy until 17th century in Europe (17세기이전 유럽에서 -시두 대처방법의 변천 과정에 대한 고찰)

  • Yun, Suk-Hyun;Kim, Yong-Jin
    • Journal of Haehwa Medicine
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    • v.19 no.2
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    • pp.1-12
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    • 2011
  • 21th century is a era of new pandemic. We are facing a new challenge and need a new way of approach. But eastern medicine and western medicine is clinging to their own way and have no intention to hear other one's opinion. Before the invention of the vaccination, smallpox has always been a major problem. Intellectuals in every country tried their best to find the treatment for the smallpox, and for Europian, didn't hesitate to borrow some knowledge of the pagon. Romans adopted the Galens concept, running away from the epidemic lesion. Christianity made smallpox Saints, and later adopted Razes heat therapy. But in the 17th century, these methods didn't turn out well, so they needed a new way of approach. By this movement, they had adopted the Chinese inoculation concept and invented a vaccination, By studying the effort of the Europian intellectuals who had tried their best to find the treatment for the smallpox until 17th century, we might get a glimps of wisdom which they had shown us. By this paper we can feel the passion to learn new techniques and their open mind and courage, which might be also needed in the 21th century, era of new pandemic.