• Title/Summary/Keyword: Model mismatch

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Using spatial misalignment Method to Measure and Evaluate unbalanced reginal tourism development in Southwest China

  • Lee, Rui;Kim, Hyung-Ho
    • International Journal of Advanced Culture Technology
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    • v.9 no.3
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    • pp.23-33
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    • 2021
  • "China's Western Development Policy" has brought multiple opportunities to the development of tourism in Southwest China including Sichuan, Guizhou, Yunnan, Chongqing and Tibet. The 4 provinces and 1 municipality overall show a certain degree of accumulation effect and coordinated development in tourism due to their location, traffic and traditional economic cooperation. This study takes the Southwest China as the research object and utilized the spatial dislocation model and the tourism spatial misalignment index to estimate the mismatch degree between tourism resources and tourism income among provinces and try to find out the internal reason background. The results show that each of the five provinces has its own advantages in index of economy, tourism resources, human resource, and transportation, leading to differences in the center of gravity of the entire region in all aspects. In view of the results of spatial dislocation analysis, suggestions for improvement and optimization are put forward to promote the high-quality development of tourism in Southwest region. development.

A Study On Effects of The Termination Conditions on Crosstalk in The A/D Converter Circuit (A/D 변환기 회로에서 터미네이션 임피던스의 crosstalk에 대한 영향 분석)

  • Lim, Han-Sang
    • Journal of the Institute of Electronics Engineers of Korea SC
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    • v.47 no.2
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    • pp.35-42
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    • 2010
  • In this study, crosstalk between dominant interconnect pairs in an A/D converter circuit is analyzed in frequency domain and effects of termination conditions on crosstalk are described, based on the practical circuit conditions. An A/D converter circuit is a mixed circuit where both clean and noisy signals coexist such that the circuit probably suffers from distortion by crosstalk. An analog input signal and the reference voltage signal, which dominate the overall conversion performance of the A/D converter circuit, are ready to be distorted by crosstalk and include specific termination conditions, such as non-matching and capacitive termination, respectively. Thus, this study presents the model of crosstalk considering impedance mismatch at both ends and analyzes effects of the practical termination conditions in the analog input and the reference voltage interconnects on crosstalk. A typical circuit configuration of the two interconnects is described and crosstalk including near-end and far-end termination impedances is modeled. Effects of the near-end impedance mismatch in the analog input interconnect and the far-end capacitive termination in the reference voltage interconnect are estimated in the frequency domain by using the model of crosstalk and experiments are performed to confirm the estimated results. Microstrip lines are used as interconnects, involving the increase of loss in high frequencies.

Novel Model for Nonlinearity of Traveling-Wave Electroabsorption Modulator according to Microwave Characteristics (마이크로파 특성에 따른 진행파형 전계흡수 변조기의 비선형 모델)

  • 윤영설;이정훈;최영완
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.40 no.8
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    • pp.580-587
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    • 2003
  • In this paper, we introduce a novel model to analyze the linearity of a TW-EAM (traveling-wave electroabsorption modulator). The device length, microwave loss (ML), and internal reflection (IR) due to impedance mismatch have effect on the linearity of a TW-EAM. The longer devices have characteristics of lower biases with minimum IMDS (intermodulation distortions). ML decreases the output power as well as the IMD value. Internal reflection has different nonlinear characteristics according to the wavelength of the input frequency and the device length. There is little change in SFDR (spurious-free dynamic range) due to ML or IR. As a result, for a 50 GHz band RF-optical communication system, a 0.8 mm-long TW-EAM with the lowest ML would have better properties by using n, which is caused by impedance, mismatch at the output port.

A Theoretical Study on Quantitative Prediction and Evaluation of Thermal Residual Stresses in Metal Matrix Composite (Case 1 : Two-Dimensional In-Plane Fiber Distribution) (금속기지 복합재료의 제조 및 성형시에 발생하는 열적잔류응력의 정량적 평가 및 예측에 관한 이론적 연구 (제 1보 : 강화재가 2차원 평면상태로 분포하는 경우))

  • Lee, Joon-Hyun;Son, Bong-Jin
    • Journal of the Korean Society for Nondestructive Testing
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    • v.17 no.2
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    • pp.89-99
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    • 1997
  • Although discontinuously reinforced metal matrix composite(MMC) is one of the most promising materials for applications of aerospace, automotive industries, the thermal residual stresses developed in the MMC due to the mismatch in coefficients of thermal expansion between the matrix and the fiber under a temperature change has been pointed out as one of the serious problem in practical applications. There are very limited nondestructive techniques to measure the residual stress of composite materials. However, many difficulties have been reported in their applications. Therefore it is important to establish analytical model to evaluate the thermal residual stress of MMC for practical engineering application. In this study, an elastic model is developed to predict the average thermal residual stresses in the matrix and fiber of a misoriented short fiber composite. The thermal residual stresses are induced by the mismatch in the coefficient of the thermal expansion of the matrix and fiber when the composite is subjected to a uniform temperature change. The model considers two-dimensional in-plane fiber misorientation. The analytical formulation of the model is based on Eshelby's equivalent inclusion method and is unique in that it is able to account for interactions among fibers. This model is more general than past models to investigate the effect of parameters which might influence thermal residual stress in composites. The present model is to investigate the effects of fiber volume fraction, distribution type, distribution cut-off angle, and aspect ratio on thermal residual stress for in-plane fiber misorientation. Fiber volume fraction, aspect ratio, and distribution cut-off angle are shown to have more significant effects on the magnitude of the thermal residual stresses than fiber distribution type for in-plane misorientation.

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Prediction of Necking in Tensile Test using Crystal Plasticity Model and Damage Model (결정소성학 모델과 손상 모델을 이용한 박판소재의 네킹 예측)

  • Kim, Jong-Bong;Hong, Seung-Hyun;Yoon, Jeong-Whan
    • Journal of the Korean Society for Precision Engineering
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    • v.29 no.8
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    • pp.818-823
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    • 2012
  • In order to predict necking behaviour of aluminium sheets, a crystal plasticity model is introduced in the finite element analysis of tensile test. Due to the computational limits of time and memory, only a small part of tensile specimen is subjected to the analysis. Grains having different orientations are subjected to numerical tensile tests and each grain is discretized by many elements. In order to predict the sudden drop of load carrying capacity after necking, a well-known Cockcroft-Latham damage model is introduced. The mismatch of grain orientation causes stress concentration at several points and damage is evolved at these points. This phenomenon is similar to void nucleation. In the same way, void growth and void coalescence behaviours are well predicted in the analysis. For the comparison of prediction capability of necking, same model is subjected to finite element analysis using uniform material properties of polycrystal with and without damage. As a result, it is shown that the crystal plasticity model can be used in prediction of necking and fracture behavior of materials accurately.

A Simple Static Noise Margin Model of MOS CML Gate in CMOS Processes

  • Jeong, Hocheol;Kang, Jaehyun;Lee, Kang-Yoon;Lee, Minjae
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.17 no.3
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    • pp.370-377
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    • 2017
  • This paper presents a simple noise margin (NM) model of MOS current mode logic (MCML) gates especially in CMOS processes where a large device mismatch deteriorates logic reliability. Trade-offs between speed and logic reliability are discussed, and a simple yet accurate NM equation to capture process-dependent degradation is proposed. The proposed NM equation is verified for 130-nm, 110-nm, 65-nm, and 40-nm CMOS processes and has errors less than 4% for all cases.

The Estimate of Manpower Demand for International Competitive Strategies in Port and Logistics Industry (항만물류산업의 국제경쟁전략에 따른 인력수요예측 연구 - 부산지역을 중심으로 -)

  • Kim, Yeong-Geun
    • Journal of Korea Port Economic Association
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    • v.21 no.4
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    • pp.55-74
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    • 2005
  • This study focuses on affording a material basis for rearranging the manpower supply system in port and logistics industry for Busan's international competitiveness strategies. First of all, the current state and future plan of port and logistics industry, as Busan's main strategic industry, are reviewed. Then theoretical background are introduced for the estimate of demand. As a methodology of this research, Cubic model is applied to estimate the demand of manpower by using 10 year time series data from 1993 to 2002. This paper also surveyed the supply side of port and logistics industry manpower in Busan area. The amounts of mismatched equilibrium between the demand and the supply are measured in this study. The concluding remarks shows some suggestions for the problem of mismatch and the relating policy planning.

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Three-Dimensional Modeling of Void Formation During Resin Transfer Molding (RESIN TRANSFER MOLDING 공정에서의 기공 형성에 관한 3차원 모델링)

  • Bae, Jun-Ho;Kang, Moon-Koo;Lim, Seoug-Taek;Lee, Woo-Il
    • Proceedings of the KSME Conference
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    • 2001.06c
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    • pp.246-250
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    • 2001
  • In resin transfer molding (RTM), resin is forced to flow through the fiber perform of inhomogeneous permeability. This inhomogeneity is responsible for the mismatch of resin velocity within and between the fiber tows. The capillary pressure of the fiber tows exacerbates the spatial variation of the resin velocity. The resulting microscopic perturbations of resin velocity at the flow front allow numerous air voids to form. In this study, a mathematical model was developed to predict the formation and migration of micro-voids during resin transfer molding. A transport equation was employed to account for the migration of voids between fiber tows. Incorporating the proposed model into a resin flow simulator, the volumetric content of micro-voids in the preform could be obtained during the simulation of resin impregnation.

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Design of Longitudinal Auto-landing Guidance and Control System Using Linear Controller-based Adaptive Neural Network

  • Choi, Si-Young;Ha, Cheol-Keun
    • 제어로봇시스템학회:학술대회논문집
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    • 2005.06a
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    • pp.1624-1627
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    • 2005
  • We proposed a design technique for auto-landing guidance and control system. This technique utilizes linear controller and neural network. Main features of this technique is to use conventional linear controller and compensate for the error coming from the model uncertainties and/or reference model mismatch. In this study, the multi-perceptron neural network with single hidden layer is adopted to compensate for the errors. Glide-slope capture logic for auto-landing guidance and control system is designed in this technique. From the simulation results, it is observed that the responses of velocity and pitch angle to commands are fairly good, which are directly related to control inputs of throttle and elevator, respectively.

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Improved Response of Time-Delay System with Integrator (적분기를 갖는 시간지연 시스템의 응답특성 개선)

  • Lee, Suk-Won;Yang, Seung-Hyun;Lee, Kyu-Yong
    • Proceedings of the KIEE Conference
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    • 1999.07b
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    • pp.930-932
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    • 1999
  • Recently a new modified Smith predictor is proposed for a time-delay system with an integrator. It is shown that the approximate model yields the zero-steady state error and the disturbance compensator improved the transient response. But in case of mismatch between the plant's time-delay and model's time-delay, the overall response is not satisfactory. In this paper, it is proposed that the proper pole is added to the new modified smith predictor to improve the overall response.

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