• Title/Summary/Keyword: Program-Models

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High redshift galaxy clusters in ELAIS-N1/N2 fields with a new color selection technique

  • Hyun, Minhee;Im, Myungshin;Kim, Jae-Woo;Lee, Seong-Kook
    • The Bulletin of The Korean Astronomical Society
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    • v.39 no.1
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    • pp.48.1-48.1
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    • 2014
  • Galaxy clusters, the largest gravitationally bound systems, are an important means to place constraints on cosmological models. Moreover, they are excellent places to test galaxy evolution models in connection to the environments. To this day, massive clusters have been found unexpectedly(Kang & Im 2009, Durret et al. 2011, Tashikawa et al. 2012) and evolution of galaxies in cluster have been still controversial (Elbaz et al. 2007, Cooper et al. 2008, Tran et al. 2009). Finding galaxy cluster candidates at z>1 in a wide, deep imaging survey data will enable us to solve the such issues of modern extragalactic astronomy. We report new candidates of galaxy clusters and their physical properties in one of the wide and deep survey fields, European Large Area ISO Survey North1(ELAIS-N1) and North2(ELAIS-N2) fields, covering sky area of and each. We also suggest a new useful color selection technique to separate 1 < z < 2 galaxies from low-z galaxies by combining multi-wavelength data from the UKIRT Infrared Deep Sky Survey Deep Extragalactic Survey (UKIDSS DXS/J and K band), Spitzer Wise-area InfraRed Extragalactic survey (SWIRE/two mid-infrared bands), Canada France Hawaii Telescope (CFHT/z band), Issac Newton Telescope(INT/ u, g, r, i, z band) and Infrared Medium-deep Survey(IMS/J band).

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GARCH-X(1, 1) model allowing a non-linear function of the variance to follow an AR(1) process

  • Didit B Nugroho;Bernadus AA Wicaksono;Lennox Larwuy
    • Communications for Statistical Applications and Methods
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    • v.30 no.2
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    • pp.163-178
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    • 2023
  • GARCH-X(1, 1) model specifies that conditional variance follows an AR(1) process and includes a past exogenous variable. This study proposes a new class from that model by allowing a more general (non-linear) variance function to follow an AR(1) process. The functions applied to the variance equation include exponential, Tukey's ladder, and Yeo-Johnson transformations. In the framework of normal and student-t distributions for return errors, the empirical analysis focuses on two stock indices data in developed countries (FTSE100 and SP500) over the daily period from January 2000 to December 2020. This study uses 10-minute realized volatility as the exogenous component. The parameters of considered models are estimated using the adaptive random walk metropolis method in the Monte Carlo Markov chain algorithm and implemented in the Matlab program. The 95% highest posterior density intervals show that the three transformations are significant for the GARCHX(1, 1) model. In general, based on the Akaike information criterion, the GARCH-X(1, 1) model that has return errors with student-t distribution and variance transformed by Tukey's ladder function provides the best data fit. In forecasting value-at-risk with the 95% confidence level, the Christoffersen's independence test suggest that non-linear models is the most suitable for modeling return data, especially model with the Tukey's ladder transformation.

Analysis of Design and Operation Performance of Micro Gas Turbine : Part 1 - Performance Analysis Program (마이크로 가스터빈 설계 및 운전 성능 분석 : 제1부 - 성능해석 프로그램)

  • Kim, Jeong Ho;Kang, Do Won;Kim, Tong Seop
    • The KSFM Journal of Fluid Machinery
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    • v.18 no.4
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    • pp.22-29
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    • 2015
  • In this study, an in-house program to predict steady state operation of micro gas turbines is constructed using MATLAB. The program consists of two parts: design and off-design simulations. The program is fully modular in its structure, and performance of each component (compressor, combustor, turbine, recuperative heat exchanger and pipe elements) is calculated in a separate calculation module using mass and energy balances as well as models for off-design characteristics. The off-design modules of compressor and turbine use performance maps, which are program inputs. The off-design operation of a micro gas turbine under development was predicted by the program. The prediction results were compared with those by commercial software, and the validity of the in-house program was confirmed.

Evaluation of Bacterial Transport Models for Saturated Column Experiments

  • Ham, Young-Ju;Kim, Song-Bae;Kim, Min-Kyu;Park, Seong-Jik
    • Journal of The Korean Society of Agricultural Engineers
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    • v.48 no.7
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    • pp.55-63
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    • 2006
  • Bacterial transport models were evaluated in this study to determine the suitable model at describing bacterial transport in saturated column experiments. Four models used in the evaluation were: advective-dispersive equation (ADE) + equilibrium sorption/retardation (ER) + kinetic reversible sorption (KR) (Model I), ADE + two-site sorption (Model 2), ADE + ER + kinetic irreversible sorption (KI) (Model 3), ADE + KR + KI (Model 4). Firstly, analyses were performed with the first experimental data, showing that Model 4 is appropriate for describing bacterial transport. Even if Model 1 and 2 fit well to the observed data, they have a defect of not including the irreversible sorption, which is directly related to mass loss of bacteria. Model 3 can not properly describe the tailing observed in the data. However, further analysis with the second data indicates that Model 4 can not describe retardation of bacteria, even if the sorption-related parameters are varied. Therefore, Model 4 is modified by incorporating retardation factor into the model, resulting in the improved fitting to the data. It indicates that the transport model, into which retardation, kinetic reversible sorption, and kinetic irreversible sorption are incorporated, is suitable at describing bacterial transport in saturated column experiments. It is expected that the selected transport model could be applied to properly analyze the bacterial transport in saturated porous media.

Study on Convergence Technique through Structural Analysis due to the Height of the Walker (보행 기구 높이에 따른 구조해석을 통한 융합 기술연구)

  • Lee, Jung-Ho;Cho, Jae-Ung
    • Journal of the Korea Convergence Society
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    • v.6 no.2
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    • pp.19-24
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    • 2015
  • Nowadays, the number of people who do not move actively or are treated for rehabilitation is increasing because of the disorder or the paralysis of their own lower body by the industrial disaster. In this study, the walker for the people whose bodies are not convenient or the old is investigated. The walkers due to the height of walker are designed and the structural simulation analysis is carried out. The study models of walker are modelled with CATIA program and analyzed with ANSYS program. As the analysis result, the models of 1, 2 and 3 have the maximum stresses extremely below the yield stress of this model and the elastic deformations at these models occurs. Among these models, As the maximum deformation of model 3 has the least value among these models, models 3 is thought to have the best durability. The safety of walker model can be estimated by the basis of the result of this study. The damage can be prevented and the durability is examined by applying this result into the design of walker. And it is possible to be grafted onto the convergence technique at design and show the esthetic sense.

Utilizing Artificial Neural Networks for Establishing Hearing-Loss Predicting Models Based on a Longitudinal Dataset and Their Implications for Managing the Hearing Conservation Program

  • Thanawat Khajonklin;Yih-Min Sun;Yue-Liang Leon Guo;Hsin-I Hsu;Chung Sik Yoon;Cheng-Yu Lin;Perng-Jy Tsai
    • Safety and Health at Work
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    • v.15 no.2
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    • pp.220-227
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    • 2024
  • Background: Though the artificial neural network (ANN) technique has been used to predict noise-induced hearing loss (NIHL), the established prediction models have primarily relied on cross-sectional datasets, and hence, they may not comprehensively capture the chronic nature of NIHL as a disease linked to long-term noise exposure among workers. Methods: A comprehensive dataset was utilized, encompassing eight-year longitudinal personal hearing threshold levels (HTLs) as well as information on seven personal variables and two environmental variables to establish NIHL predicting models through the ANN technique. Three subdatasets were extracted from the afirementioned comprehensive dataset to assess the advantages of the present study in NIHL predictions. Results: The dataset was gathered from 170 workers employed in a steel-making industry, with a median cumulative noise exposure and HTL of 88.40 dBA-year and 19.58 dB, respectively. Utilizing the longitudinal dataset demonstrated superior prediction capabilities compared to cross-sectional datasets. Incorporating the more comprehensive dataset led to improved NIHL predictions, particularly when considering variables such as noise pattern and use of personal protective equipment. Despite fluctuations observed in the measured HTLs, the ANN predicting models consistently revealed a discernible trend. Conclusions: A consistent correlation was observed between the measured HTLs and the results obtained from the predicting models. However, it is essential to exercise caution when utilizing the model-predicted NIHLs for individual workers due to inherent personal fluctuations in HTLs. Nonetheless, these ANN models can serve as a valuable reference for the industry in effectively managing its hearing conservation program.

Aerodynamic Design Program for Centrifugal/Mixed-flow Compressors - Part I : Meanline Design and Performance Prediction - (원심/사류압축기의 공력설계 프로그램 개발 - 제1부 : 평균유선 설계/성능해석 -)

  • Oh, Jong-Sik
    • 유체기계공업학회:학술대회논문집
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    • 2003.12a
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    • pp.457-463
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    • 2003
  • A general program of meanline design and/or performance prediction for centrifugal/mixed-flow compressors is successfully commercialized using various empirical loss models. 4 types of diffusers, 3 types of exit elements, shrouded/unshrouded impellers and real gas option are included in the program capabilities. Total 16 cases of benchmark test results proved its reliability to be effectively utilized in the development processes.

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Switched Reluctance Motor Design and Analysis with LabView Program (LabView를 이용한 Switched Reluctance Motor 설계기술 개발)

  • Shin, Pan-Seok;Otaduy, Pedro J.
    • Proceedings of the KIEE Conference
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    • 2001.10a
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    • pp.21-23
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    • 2001
  • A design and analysis program is proposed for switched reluctance motor using an analytical method and a CAD program LabVIEW. The algorithm uses conventional permeance method, in which flux linkages, inductances and torques are calculated numerically. In order to analyze a dynamic characteristics of the motor, voltage control scheme is fallen and a single pulse operation is applied. 2 SRM models are analyzed under the given specifications and constraints. The results compared with measured data.

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Nonlinear mixed models for characterization of growth trajectory of New Zealand rabbits raised in tropical climate

  • de Sousa, Vanusa Castro;Biagiotti, Daniel;Sarmento, Jose Lindenberg Rocha;Sena, Luciano Silva;Barroso, Priscila Alves;Barjud, Sued Felipe Lacerda;de Sousa Almeida, Marisa Karen;da Silva Santos, Natanael Pereira
    • Animal Bioscience
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    • v.35 no.5
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    • pp.648-658
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    • 2022
  • Objective: The identification of nonlinear mixed models that describe the growth trajectory of New Zealand rabbits was performed based on weight records and carcass measures obtained using ultrasonography. Methods: Phenotypic records of body weight (BW) and loin eye area (LEA) were collected from 66 animals raised in a didactic-productive module of cuniculture located in the southern Piaui state, Brazil. The following nonlinear models were tested considering fixed parameters: Brody, Gompertz, Logistic, Richards, Meloun 1, modified Michaelis-Menten, Santana, and von Bertalanffy. The coefficient of determination (R2), mean squared error, percentage of convergence of each model (%C), mean absolute deviation of residuals, Akaike information criterion (AIC), and Bayesian information criterion (BIC) were used to determine the best model. The model that best described the growth trajectory for each trait was also used under the context of mixed models, considering two parameters that admit biological interpretation (A and k) with random effects. Results: The von Bertalanffy model was the best fitting model for BW according to the highest value of R2 (0.98) and lowest values of AIC (6,675.30) and BIC (6,691.90). For LEA, the Logistic model was the most appropriate due to the results of R2 (0.52), AIC (783.90), and BIC (798.40) obtained using this model. The absolute growth rates estimated using the von Bertalanffy and Logistic models for BW and LEA were 21.51g/d and 3.16 cm2, respectively. The relative growth rates at the inflection point were 0.028 for BW (von Bertalanffy) and 0.014 for LEA (Logistic). Conclusion: The von Bertalanffy and Logistic models with random effect at the asymptotic weight are recommended for analysis of ponderal and carcass growth trajectories in New Zealand rabbits. The inclusion of random effects in the asymptotic weight and maturity rate improves the quality of fit in comparison to fixed models.