• Title/Summary/Keyword: Random selection

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Comparison of CT Exposure Dose Prediction Models Using Machine Learning-based Body Measurement Information (머신러닝 기반 신체 계측정보를 이용한 CT 피폭선량 예측모델 비교)

  • Hong, Dong-Hee
    • Journal of radiological science and technology
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    • v.43 no.6
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    • pp.503-509
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    • 2020
  • This study aims to develop a patient-specific radiation exposure dose prediction model based on anthropometric data that can be easily measurable during CT examination, and to be used as basic data for DRL setting and radiation dose management system in the future. In addition, among the machine learning algorithms, the most suitable model for predicting exposure doses is presented. The data used in this study were chest CT scan data, and a data set was constructed based on the data including the patient's anthropometric data. In the pre-processing and sample selection of the data, out of the total number of samples of 250 samples, only chest CT scans were performed without using a contrast agent, and 110 samples including height and weight variables were extracted. Of the 110 samples extracted, 66% was used as a training set, and the remaining 44% were used as a test set for verification. The exposure dose was predicted through random forest, linear regression analysis, and SVM algorithm using Orange version 3.26.0, an open software as a machine learning algorithm. Results Algorithm model prediction accuracy was R^2 0.840 for random forest, R^2 0.969 for linear regression analysis, and R^2 0.189 for SVM. As a result of verifying the prediction rate of the algorithm model, the random forest is the highest with R^2 0.986 of the random forest, R^2 0.973 of the linear regression analysis, and R^2 of 0.204 of the SVM, indicating that the model has the best predictive power.

Simulation Study on Model Selection Based on AIC under Unbalanced Design in Linear Mixed Effect Models (불균형 자료에서 AIC를 이용한 선형혼합모형 선택법의 효율에 대한 모의실험 연구)

  • Lee, Yong-Hee
    • The Korean Journal of Applied Statistics
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    • v.23 no.6
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    • pp.1169-1178
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    • 2010
  • This article consider a performance model selection based on AIC under unbalanced deign in linear mixed effect models. Vaida and Balanchard (2005) proposed conditional AIC for model selection in linear mixed effect models when the prediction of random effects is of primary interest. Theoretical properties of cAIC and related criteria have been investigated by Liang et al. (2008) and Greven and Kneib (2010). However, all of the simulation studies were performed under a balanced design. Even though functional form of AIC remain same even under the unbalanced deign, it is worthwhile to investigate performance of AIC based model selection criteria under the unbalanced design. The simulation study in this article shows how unbalancedness affects model selection in linear mixed effect models.

Evaluation of Optimum Genetic Contribution Theory to Control Inbreeding While Maximizing Genetic Response

  • Oh, S.H.
    • Asian-Australasian Journal of Animal Sciences
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    • v.25 no.3
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    • pp.299-303
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    • 2012
  • Inbreeding is the mating of relatives that produce progeny having more homozygous alleles than non-inbred animals. Inbreeding increases numbers of recessive alleles, which is often associated with decreased performance known as inbreeding depression. The magnitude of inbreeding depression depends on the level of inbreeding in the animal. Level of inbreeding is expressed by the inbreeding coefficient. One breeding goal in livestock is uniform productivity while maintaining acceptable inbreeding levels, especially keeping inbreeding less than 20%. However, in closed herds without the introduction of new genetic sources high levels of inbreeding over time are unavoidable. One method that increases selection response and minimizes inbreeding is selection of individuals by weighting estimated breeding values with average relationships among individuals. Optimum genetic contribution theory (OGC) uses relationships among individuals as weighting factors. The algorithm is as follows: i) Identify the individual having the best EBV; ii) Calculate average relationships ($\bar{r_j}$) between selected and candidates; iii) Select the individual having the best EBV adjusted for average relationships using the weighting factor k, $EBV^*=EBV_j(1-k\bar{{r}_j})$ Repeat process until the number of individuals selected equals number required. The objective of this study was to compare simulated results based on OGC selection under different conditions over 30 generations. Individuals (n = 110) were generated for the base population with pseudo random numbers of N~ (0, 3), ten were assumed male, and the remainder female. Each male was mated to ten females, and every female was assumed to have 5 progeny resulting in 500 individuals in the following generation. Results showed the OGC algorithm effectively controlled inbreeding and maintained consistent increases in selection response. Difference in breeding values between selection with OGC algorithm and by EBV only was 8%, however, rate of inbreeding was controlled by 47% after 20 generation. These results indicate that the OGC algorithm can be used effectively in long-term selection programs.

Movie Box-office Prediction using Deep Learning and Feature Selection : Focusing on Multivariate Time Series

  • Byun, Jun-Hyung;Kim, Ji-Ho;Choi, Young-Jin;Lee, Hong-Chul
    • Journal of the Korea Society of Computer and Information
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    • v.25 no.6
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    • pp.35-47
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    • 2020
  • Box-office prediction is important to movie stakeholders. It is necessary to accurately predict box-office and select important variables. In this paper, we propose a multivariate time series classification and important variable selection method to improve accuracy of predicting the box-office. As a research method, we collected daily data from KOBIS and NAVER for South Korean movies, selected important variables using Random Forest and predicted multivariate time series using Deep Learning. Based on the Korean screen quota system, Deep Learning was used to compare the accuracy of box-office predictions on the 73rd day from movie release with the important variables and entire variables, and the results was tested whether they are statistically significant. As a Deep Learning model, Multi-Layer Perceptron, Fully Convolutional Neural Networks, and Residual Network were used. Among the Deep Learning models, the model using important variables and Residual Network had the highest prediction accuracy at 93%.

A Study on the Optimal Location Selection for Hydrogen Refueling Stations on a Highway using Machine Learning (머신러닝 기반 고속도로 내 수소충전소 최적입지 선정 연구)

  • Jo, Jae-Hyeok;Kim, Sungsu
    • Journal of Cadastre & Land InformatiX
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    • v.51 no.2
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    • pp.83-106
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    • 2021
  • Interests in clean fuels have been soaring because of environmental problems such as air pollution and global warming. Unlike fossil fuels, hydrogen obtains public attention as a eco-friendly energy source because it releases only water when burned. Various policy efforts have been made to establish a hydrogen based transportation network. The station that supplies hydrogen to hydrogen-powered trucks is essential for building the hydrogen based logistics system. Thus, determining the optimal location of refueling stations is an important topic in the network. Although previous studies have mostly applied optimization based methodologies, this paper adopts machine learning to review spatial attributes of candidate locations in selecting the optimal position of the refueling stations. Machine learning shows outstanding performance in various fields. However, it has not yet applied to an optimal location selection problem of hydrogen refueling stations. Therefore, several machine learning models are applied and compared in performance by setting variables relevant to the location of highway rest areas and random points on a highway. The results show that Random Forest model is superior in terms of F1-score. We believe that this work can be a starting point to utilize machine learning based methods as the preliminary review for the optimal sites of the stations before the optimization applies.

Aptamers as Functional Nucleic Acids: in vitro Selection and Biotechnological Applications

  • You, Kyung-Man;Lee, Sang-Hyun;Aesul Im;Lee, Sun-Bok
    • Biotechnology and Bioprocess Engineering:BBE
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    • v.8 no.2
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    • pp.64-75
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    • 2003
  • Aptamers are functional nucleic acids that can specially bind to proteins, peptides, amino acids. nucleotides, drugs, vitamins and other organic and inorganic compounds. The aptamers are identified from random DNA or RNA libraries by a SELEX (systematic evolution of ligands by exponential amplification) process. As aptamers have the advantage, and potential ability to be released from the limitations of antibodies, they are attractive to a wide range of therapeutic and diagnostic applications. Aptamers, with a high-affinity and specificity, could fulfil molecular the recognition needs of various fields in biotechnology. In this work, we reviewed some aptamer Selection techniques, properties, medical applications of their molecules and their biotechnological applications, such as ELONA (enzyme linked oligonucleotide assay), flow cytometry, biosensors, electrophoresis, chromatography and microarrays.

Pattern Recognition with Rotation Invariant Multiresolution Features

  • Rodtook, S.;Makhanov, S.S.
    • 제어로봇시스템학회:학술대회논문집
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    • 2004.08a
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    • pp.1057-1060
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    • 2004
  • We propose new rotation moment invariants based on multiresolution filter bank techniques. The multiresolution pyramid motivates our simple but efficient feature selection procedure based on the fuzzy C-mean clustering, combined with the Mahalanobis distance. The procedure verifies an impact of random noise as well as an interesting and less known impact of noise due to spatial transformations. The recognition accuracy of the proposed techniques has been tested with the preceding moment invariants as well as with some wavelet based schemes. The numerical experiments, with more than 30,000 images, demonstrate a tangible accuracy increase of about 3% for low noise, 8% for the average noise and 15% for high level noise.

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Fashion Lifestyle Segmentation of College Women′s Apparel Market: Informations Sources.Clothing Benefits Sought.Store Selection Criteria (패션 라이프스타일에 의한 여대생 의류 시장 세분화 -패션정보원.의복추구이점.상점선택기준-)

  • 정혜영
    • The Research Journal of the Costume Culture
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    • v.3 no.2
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    • pp.393-408
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    • 1995
  • The purpose of this study was to segment the female college apparel market based on fashion lifestyle and to develop a profile of each segment regard to fashion information sources, clothing benefits sought, and store selection criteria. The data were collected through questionnaire by random sample of 522 female college students. By cluster analysis of lifestyle factors, three groups were identified. (fashion leaders, fashion followers and fashion aversion), Three groups were then compared through multivariate analysis of variance on 11 fashion sources, 10 clothing benefits sought and 90 store selective criteria. Significant difference were found among the three groups on all these variables which indicate that fashion lifestyle can be a useful base for segmenting female apparel market and these groups are unique in terms of fashion information sources, clothing benefits sought and store selective criterias.

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APPLICATION OF GENETIC-BASED FUZZY INFERENCE TO FUZZY CONTROL

  • Park, Daihee;Kandel, Abraham;Langholz, Gideon
    • Journal of the Korean Institute of Intelligent Systems
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    • v.2 no.2
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    • pp.3-33
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    • 1992
  • The successful application of fuzzy reasoning models to fuzzy control systems depends on a number of parameters, such as fuzzy membership functions, that are usually decided upon subjectively. It is shown ill this paper that the performance of fuzzy control systems call be improved if the fuzzy reasoning model is supplemented by a genetic-based learning mechanism. The genetic algorithm enables us to generate all optimal set of parameters for the fuzzy reasoning model based either on their initial subjective selection or on a random selection. It is shown that if knowledge of the domain is available, it is exploited by the genetic algorithm leading to an even better performance of the fuzzy controller.

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AGV travel time estimation for an AGV-based transport system (AGV기반 운반체계에서의 차량이동시간에 관한 연구)

  • 구평회;장재진
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 2000.04a
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    • pp.5-8
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    • 2000
  • Vehicle travel time (empty travel time pius loaded travel time) is a key parameter for designing AGV-based material handling systems. Especially, the determination of empty vehicle travel time is difficult because of the stochastic nature of the empty vehicle locations. This paper presents a method to estimate vehicle travel times for AGV-based material transport systems. The model considers probabilistic aspects for the travel time and vehicle location under random vehicle selection rule and nearest vehicle selection rule. The estimation of empty travel time is of major effort. Simulation experiments are used to verify the proposed travel time model, and the simulation results show that the presented model provides reasonable travel time estimations.

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