• Title/Summary/Keyword: influence functions

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Discovery of Cellular RhoA Functions by the Integrated Application of Gene Set Enrichment Analysis

  • Chun, Kwang-Hoon
    • Biomolecules & Therapeutics
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    • v.30 no.1
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    • pp.98-116
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    • 2022
  • The small GTPase RhoA has been studied extensively for its role in actin dynamics. In this study, multiple bioinformatics tools were applied cooperatively to the microarray dataset GSE64714 to explore previously unidentified functions of RhoA. Comparative gene expression analysis revealed 545 differentially expressed genes in RhoA-null cells versus controls. Gene set enrichment analysis (GSEA) was conducted with three gene set collections: (1) the hallmark, (2) the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway, and (3) the Gene Ontology Biological Process. GSEA results showed that RhoA is related strongly to diverse pathways: cell cycle/growth, DNA repair, metabolism, keratinization, response to fungus, and vesicular transport. These functions were verified by heatmap analysis, KEGG pathway diagramming, and direct acyclic graphing. The use of multiple gene set collections restricted the leakage of information extracted. However, gene sets from individual collections are heterogenous in gene element composition, number, and the contextual meaning embraced in names. Indeed, there was a limit to deriving functions with high accuracy and reliability simply from gene set names. The comparison of multiple gene set collections showed that although the gene sets had similar names, the gene elements were extremely heterogeneous. Thus, the type of collection chosen and the analytical context influence the interpretation of GSEA results. Nonetheless, the analyses of multiple collections made it possible to derive robust and consistent function identifications. This study confirmed several well-described roles of RhoA and revealed less explored functions, suggesting future research directions.

Extending the calibration between empirical influence function and sample influence function to t-statistic (경험적 영향함수와 표본영향함수 간 차이 보정의 t통계량으로의 확장)

  • Kang, Hyunseok;Kim, Honggie
    • The Korean Journal of Applied Statistics
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    • v.34 no.6
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    • pp.889-904
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    • 2021
  • This study is a follow-up study of Kang and Kim (2020). In this study, we derive the sample influence functions of the t-statistic which were not directly derived in previous researches. Throughout these results, we both mathematically examine the relationship between the empirical influence function and the sample influence function, and consider a method to approximate the sample influence function by the empirical influence function. Also, the validity of the relationship between an approximated sample influence function and the empirical influence function is verified by a simulation of a random sample of size 300 from normal distribution. As a result of the simulation, the relationship between the sample influence function which is derived from the t-statistic and the empirical influence function, and the method of approximating the sample influence function through the empirical influence function were verified. This research has significance in proposing both a method which reduces errors in approximation of the empirical influence function and an effective and practical method that evolves from previous research which approximates the sample influence function directly through the empirical influence function by constant revision.

Robust Optimal Design of a Decoupled Vibratory Microgyroscope Considering Fabrication Influence (공정영향을 고려한 비연성 진동형 마이크로 자이로스코프의 강건 최적 설계)

  • Jeong Hee-Moon;Ha Sung Kyu
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.28 no.8 s.227
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    • pp.1065-1074
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    • 2004
  • A robust optimal design considering fabrication influence has been performed for the decoupled vibratory microgyroscope fabricated by the bulk micromachining. For the analysis of the gyroscope, a design tool has been developed, by which user can perform the system level design considering electric signal process and the fabrication influence as well as mechanical characteristics. An initial design of the gyroscope is performed satisfying the performances of scale factor (or sensitivity) and phase delay, which depend on the frequency difference between driving and sensing resonant frequencies. The objective functions are formulated in order to reduce the variances of the frequency difference and the frequency in itself by fabrication error. To certify the results, the standard deviations are calculated through the Monte Caries Simulation (MCS) and compared initial deviation that is measured fabricated gyroscope chip.

Calibration by Median Regression

  • Jinsan Yang;Lee, Seung-Ho
    • Journal of the Korean Statistical Society
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    • v.28 no.2
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    • pp.265-277
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    • 1999
  • Classical and inverse estimation methods are two well known methods in statistical calibration problems. When there are outliers, both methods have large MSE's and could not estimate the input value correctly. We suggest median calibration estimation based on the LD-statistics. To investigate the robust performances, the influence function of the median calibration estimator is calculated and compared with other methods. When there are outliers in the response variables, the influence function is found to be bounded. In simulation studies, the MSE's for each calibration methods are compared. The estimated inputs as well as the performance of the influence functions are calculated.

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Influence in Testing the Equality of Two Covariance Matrices (두개의 공분산 행렬의 동질성 검정에서의 영향치 분석)

  • Myung Geun Kim
    • The Korean Journal of Applied Statistics
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    • v.7 no.2
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    • pp.213-224
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    • 1994
  • A diagnostic method useful for detecting outliers in testing the equality of two covariance metrics is developed using the influence curve approach. This method is easily generalized to more than two covariance matrices. A sample version for the influence measure of detecting outliers is considered based on the empirical distribution functions. The sample version includes as its component terms the well-known test statistic for detecting one outlier at a time introduced by Wilks and its generalization to the two-group case.

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Simultaneous Optimization Techniques for Multi-purpose Response Functions (다목적 반응함수들의 동시 최적화수법)

  • Park, Sung-Hyun
    • Journal of the military operations research society of Korea
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    • v.7 no.1
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    • pp.118-138
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    • 1981
  • In many response surface optimization problems for industrial processes, there are more than two responses of interest, and we want to find the optimal levels of the factors that influence the responses. This paper is to propose how to set up the desirability functions to find the optimum for a given set of data, and to propose how to analyse the data and the desirability functions to determine an optimal operating condition for the factors. To implement the proposed method in practice, a FORTRAN computer program was written and explained. Finally, an industrial example is illustrated to explain the proposed technique and the source list of the computer program is attached for the users.

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The Characteristics of Wave Statistical Data and Quality Assurance (파랑 통계자료의 특성과 신뢰성 검토)

  • Park, J.H.
    • Journal of Power System Engineering
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    • v.13 no.2
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    • pp.63-70
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    • 2009
  • This paper discusses the influence on long-tenn predictions of the ship response in ocean by using the Global Wave Statistics data, GWS, and wave information from the remote sensing satellites. GWS's standard scatter diagrams of significant wave height and zero-crossing wave period are suggested to be corrected to a round number of 0.01/1000 fitted with a statistical analytic model of the conditional lognormal distribution for zero-crossing wave period. The GEOSAT satellite data are utilized which presented by I. R. Young and G. J. Holland (1996, named as GEOSAT data). At first, qualities of this data are investigated, and statistical characteristic trends are studied by means of applying known probability distribution functions. The wave height data of GEOSAT are compared to the data observed onboard merchant ships, the data observed by measure instrument installed on the ocean-going container ship and so on. To execute a long-tenn prediction of ship response, joint probability functions between wave height and wave period are introduced, therefore long-term statistical predictions are executed by using the functions.

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FINANCIAL MODELS INDUCED FROM AUXILIARY INDICES AND TWITTER DATA

  • Oh, Jae-Pill
    • Korean Journal of Mathematics
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    • v.22 no.3
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    • pp.529-552
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    • 2014
  • As we know, some indices and data are strong influence to the price movement of some assets now, but not to another assets and in future. Thus we define some asset models for several time intervals; intraday, weekly, monthly, and yearly asset models. We define these asset models by using Brownian motion with volatility and Poisson process, and several deterministic functions(index function, twitter data function and big-jump simple function etc). In our asset models, these deterministic functions are the positive or negative levels of auxiliary indices, of analyzed data, and for imminent and extreme state(for example, financial shock or the highest popularity in the market). These functions determined by indices, twitter data and shocking news are a kind of one of speciality of our asset models. For reasonableness of our asset models, we introduce several real data, figurers and tables, and simulations. Perhaps from our asset models, for short-term or long-term investment, we can classify and reference many kinds of usual auxiliary indices, information and data.

A Study on Tire Radial Force Variation and Modal Testing (타이어 상하 힘변동과 모드 시험에 관한 연구)

  • Park, S.K.;Kim, J.K.;Song, S.K.
    • Journal of Power System Engineering
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    • v.2 no.3
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    • pp.55-59
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    • 1998
  • This paper probes into the influence of tire uniformity on tire's modal parameters with the method of experimental modal analysis. Two radial tires of the same kind with different uniformity level are taken to be tested at different exciting points and real modal parameters are abstracted. The differences of their modal parameters are presented. Then tire transfer functions are constructed with experimental modal parameters and ideal modal parameters respectively. It is found that the measured transfer functions of tire of good uniformity are closer to ideal transfer function than that of tire of bad uniformity. The study shows evident interrelation of experimental modal parameters and tire uniformity, and further study should be of great value.

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An Experimental study on Prediction of Back-bead Geometry in Pipeline Using the GMA Welding Process (GMA를 이용한 배관용접의 이면비드 형상예측에 관한 실험적 연구)

  • Kim, Ji-Sun;Kim, Ill-Soo;Na, Hyun-Ho;Lee, Ji-Hye
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.20 no.1
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    • pp.74-80
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    • 2011
  • In this study, a variety of welding experiments were carried out to optimize root-pass welding process using GMA process. Based on the experimental results, optimal welding conditions were selected after analyzing correlation between welding parameters and back-bead geometry. Then, effectiveness of empirical models developed was compared and analyzed, and optimized empirical models were finally developed for predicting back-bead by analyzing the main effect of each factor which affects back-bead geometry and their influence on interaction. Also, functions proper for expressing the surface of back-bead were selected using diverse quadratic functions, and back-bead geometry was visualized using empirical models developed and quadratic functions.