• Title/Summary/Keyword: misclassification

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Validity and Reliability of a Dish-based, Semi-quantitative Food Frequency Questionnaire for Korean Diet and Cancer Research

  • Park, Min-Kyung;Noh, Hwa-Young;Song, Na-Yeun;Paik, Hee-Young;Park, So-Hee;Joung, Hyo-Jee;Song, Won-O;Kim, Jeong-Seon
    • Asian Pacific Journal of Cancer Prevention
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    • v.13 no.2
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    • pp.545-552
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    • 2012
  • This study evaluated the validity and reliability of applying a newly developed dish-based, semi-quantitative food frequency questionnaire (FFQ) for Korean diet and cancer research. The subjects in the present study were 288 Korean adults over 30 years of age who had completed two FFQs and four 3-day diet records (DRs) from May 2008 to February 2009. Student's t-tests, Chi-square tests, and Spearman's rank correlation coefficients were used to estimate and compare intakes from different dietary assessment tools. Agreement in quintiles was calculated to validate agreement between the results of the second FFQ (FFQ-2) conducted in February 2009 and the DRs. Median Spearman's correlation coefficients between the intake of nutrients and foods assessed by the FFQ-1 and FFQ-2 were 0.59 and 0.57, respectively, and the coefficients between the intake of nutrients and foods assessed by the FFQ-2 and the DRs were 0.31 and 0.29, respectively. The quintile classifications of same or adjacent quintile for intake of nutrients and foods were 64% and 65%, respectively. Misclassification into opposite quintiles occurred in less than 5% for all dietary factors. Thus this newly-developed, Korean dish-based FFQ demonstrated moderate correspondence with the four 3-day DRs. Its reliability and validity are comparable to those reported in other studies.

A New Ensemble Machine Learning Technique with Multiple Stacking (다중 스태킹을 가진 새로운 앙상블 학습 기법)

  • Lee, Su-eun;Kim, Han-joon
    • The Journal of Society for e-Business Studies
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    • v.25 no.3
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    • pp.1-13
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    • 2020
  • Machine learning refers to a model generation technique that can solve specific problems from the generalization process for given data. In order to generate a high performance model, high quality training data and learning algorithms for generalization process should be prepared. As one way of improving the performance of model to be learned, the Ensemble technique generates multiple models rather than a single model, which includes bagging, boosting, and stacking learning techniques. This paper proposes a new Ensemble technique with multiple stacking that outperforms the conventional stacking technique. The learning structure of multiple stacking ensemble technique is similar to the structure of deep learning, in which each layer is composed of a combination of stacking models, and the number of layers get increased so as to minimize the misclassification rate of each layer. Through experiments using four types of datasets, we have showed that the proposed method outperforms the exiting ones.

Claimed Adverse Events of Korean Medicine in South Korea: Analysis of Cases in the Korea Medical Dispute Mediation and Arbitration Agency Databases (한의 의료와 연관된 조정 요청 이상반응: 한국의료분쟁조정중재원 접수사례 분석)

  • Hwang, Hye-Won;Lee, Ji-Sun;Kim, Kun Hyung
    • Korean Journal of Acupuncture
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    • v.34 no.3
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    • pp.126-135
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    • 2017
  • Objectives : The purpose of this study was to describe the type of claimed adverse events related to Korean Medicine practices in South Korea. Methods : Claims with regard to the Korean Medicine practice submitted to the Korea Medical Dispute Mediation and Arbitration Agency from April 2012 to December 2016 were collected. We analyzed claims that explicitly reported the type of Korean medicine intervention and were deemed as being adverse events as defined by the Korea Good Clinical Practice. Claims that did not mention the Korean medicine practice explicitly or those related to the patient's dissatisfaction to the service rather than adverse health outcomes were excluded. Types, related interventions and the suspected severity of claimed adverse events were summarized. Results : Of 197 claims obtained, 140 claim cases were eligible and 144 claimed events were deemed as possible adverse events of the Korean medicine practice. Pain(16%), local infection/inflammation(12%) and neurological symptoms(11%) were the most frequently reported types of claimed adverse events. Thirty-nine claimed serious adverse events(SAE) were identified, including pneumothorax(28.2%) and death(17.9%). Conclusions : A wide range of claimed adverse events were identified. Routine monitoring of claims data may provide undetected safety information with regard to the Korean medicine practice. High risk of misclassification of the intervention and claimed adverse events due to insufficient information is the main caveat of this study.

Discrimination of Natural Earthquakes and Explosions in Spectral Domain (주파수 영역에서의 인공지진과 자연지진의 식별)

  • 김성균;김명수
    • Economic and Environmental Geology
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    • v.36 no.3
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    • pp.201-212
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    • 2003
  • Recently, the ability of earthquake detection in the Kyungsang Basin of southeastern Korean Peninsula is greatly improved since seismic stations including seismic network of KIGAM(Korea Institute of Geoscience and Mineral Resources) have been significantly increased. However, a large number of signals from explosions are recorded because of frequent medium to large chemical explosions. The discrimination between natural earthquakes and explosions in the Basin has become an important issue. High frequency local records from 43 earthquakes and 43 explosions with comparable magnitude are selected to establish a reliable discrimination technique in the Basin. Several discrimination techniques in spectral domain using spectral amplitude ratios among Pg, Sg, and Lg waves are widely examined with tile selected data. Among them the Pg/Lg spectral ratio method is appeared to be a good discrimination technique to improve the discrimination power. Multivariate discriminant analysis is also applied to the Pg/Lg spectral ratios. The discrimination power of the Pg/Lg ratios for distance corrected three component record compared to uncorrected vertical component one shows distinct improvement. In the frequency band 4 to 14 Hz, Pg/Lg spectral ratio for distance corrected three component record provides discrimination power with a total misclassification probability of only 0.89%.

Factors Influencing Vaccination in Korea: Findings From Focus Group Interviews

  • Park, Bomi;Choi, Eun Jeong;Park, Bohyun;Han, Hyejin;Cho, Su Jin;Choi, Hee Jung;Lee, Seonhwa;Park, Hyesook
    • Journal of Preventive Medicine and Public Health
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    • v.51 no.4
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    • pp.173-180
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    • 2018
  • Objectives: Immunization is considered one of the most successful and cost-effective public health interventions protecting communities from preventable infectious diseases. The Korean government set up a dedicated workforce for national immunization in 2003, and since then has made strides in improving vaccination coverage across the nation. However, some groups remain relatively vulnerable and require intervention, and it is necessary to address unmet needs to prevent outbreaks of communicable diseases. This study was conducted to characterize persistent challenges to vaccination. Methods: The study adopted a qualitative method in accordance with the Consolidated Criteria for Reporting Qualitative Research checklist. Three focus group interviews were conducted with 15 professionals in charge of vaccination-related duties. The interviews were conducted according to a semi-structured guideline, and thematic analysis was carried out. Data saturation was confirmed when the researchers agreed that no more new codes could be found. Results: A total of 4 main topics and 11 subtopics were introduced regarding barriers to vaccination. The main topics were vaccine hesitancy, personal circumstances, lack of information, and misclassification. Among them, vaccine hesitancy was confirmed to be the most significant factor impeding vaccination. It was also found that the factors hindering vaccination had changed over time and disproportionately affected certain groups. Conclusions: The study identified ongoing unmet needs and barriers to vaccination despite the accomplishments of the National Immunization Program. The results have implications for establishing tailored interventions that target context- and group-specific barriers to improve timely and complete vaccination coverage.

Validation of the International Classification of Diseases 10th Edition Based Injury Severity Score(ICISS) (ICD-10을 이용한 ICISS의 타당도 평가)

  • Jung, Ku-Young;Kim, Chang-Yup;Kim, Yong-Ik;Shin, Young-Soo;Kim, Yoon
    • Journal of Preventive Medicine and Public Health
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    • v.32 no.4
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    • pp.538-545
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    • 1999
  • Objective : To compare the predictive power of International Classification of Diseases 10th Edition(ICD-10) based International Classification of Diseases based Injury Severity Score(ICISS) with Trauma and Injury Severity Score(TRISS) and International Classification of Diseases 9th Edition Clinical Modification(ICD-9CM) based ICISS in the injury severity measure. Methods : ICD-10 version of Survival Risk Ratios(SRRs) was derived from 47,750 trauma patients from 35 Emergency Centers for 1 year. The predictive power of TRISS, the ICD-9CM based ICISS and ICD-10 based ICISS were compared in a group of 367 severely injured patients admitted to two university hospitals. The predictive power was compared by using the measures of discrimination(disparity, sensitivity, specificity, misclassification rates, and ROC curve analysis) and calibration(Hosmer-Lemeshow goodness-of-fit statistics), all calculated by logistic regression procedure. Results : ICD-10 based ICISS showed a lower performance than TRISS and ICD-9CM based ICISS. When age and Revised Trauma Score(RTS) were incorporated into the survival probability model, however, ICD-10 based ICISS full model showed a similar predictive power compared with TRISS and ICD-9CM based ICISS full model. ICD-10 based ICISS had some disadvantages in predicting outcomes among patients with intracranial injuries. However, such weakness was largely compensated by incorporating age and RTS in the model. Conclusions : The ICISS methodology can be extended to ICD-10 horizon as a standard injury severity measure in the place of TRISS, especially when age and RTS were incorporated in the model. In patients with intracranial injuries, the predictive power of ICD-10 based ICISS was relatively low because of differences in the classifying system between ICD-10 and ICD-9CM.

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Hepatotoxic Events Associated with Herbal Medicinal Products, Folk Remedies and Food Supplements in Korea (국내에서 보고된 한약 및 민간요법, 건강식품 관련 약인성간손상에 대한 체계적 고찰)

  • Park, Hae-Mo;Jang, In-Soo;Lee, Sun-Dong
    • The Journal of Korean Medicine
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    • v.26 no.2 s.62
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    • pp.152-165
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    • 2005
  • Background: The use of herbal preparations as remedies for various medical conditions has continuously increased in Korea Large proportions of Korean patients use herbal medicinal products, folk remedies, and food supplements. However, studies on the safety of herbal products arc conducted on a less than sufficient basis even in the countries like Korea where herbal medicine is being used extensively. Some of the reports on the safety of herbs were done by the doctors of western medicine but lack of knowledge and misclassification led to misunderstandings. Objecitves: This study aims to review the recent evidences on hepatotoxic events associated with the use of herbal medicinal products, folk remedy, and food supplements. In the process, this review will grasp trends in this field of studies and will direct further researches into the right direction. Methods: Systematic literature searches were performed on MedRic and MEDLIS in Korea. Screening and selection of the articles and the extraction of data were performed independently by two of authors. There were no restrictions regarding the published date. In order to avoid bias, the articles written by medical doctors, not by oriental doctors were selected. 43 journals were chosen for the review. Results: Analyzing the number of journals, studies on the drug-induced liver injury were increased after the year 2000. The proportion of herbal and folk remedy associated hepatotoxic injuries in all drug-induced liver injury was $21.0\%-30.0\%$. But criterion for herbal medicine is rather vague and limited objective data hindered objectiveness. Few of single medicinal herbs and combination preparations were associated with hepatotoxic injuries. But because of lack of objectivity, further researches must be conducted to yield more concrete results. Conclusions: yield more concrete results. Incidence figures are largely unknown, and in most cases a causal attribution is not established. The challenge for the future is to systematically research this area, educate all parties involved, and minimize patient risks.

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Estimating the Spatial Distribution of Satellite Image Classification Error Using Index of Spatial Distribution (공간분포지표를 이용한 위성영상 분류오차의 공간적 분포 평가)

  • 이병길;김용일;어양담
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.17 no.2
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    • pp.129-136
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    • 1999
  • The quality of image classification results is not always uniform over entire image. Thus, this study proposes the concept of ISDd (Index of Spatial Distribution by distance) and ISDs (ISD by scatteredness) for the evaluation of unevenness of result quality, and spatial distribution of satellite image classification errors. The ISDd is indexed mean distance of misclassified pixels and the ISDs is statistical indicator of scatteredness of misclassified pixels. In this study, the ISDd and the ISDs are calculated and evaluated for some satellite images, then misclassified area is extracted and the reasons of misclassification are examined. As the result of this study, using both the ISDd and the ISDs, the basis of decision on adoption/rejection of classification results is offered at sub-image level by evaluation of the local aggregation of misclassified pixels. Using Index of Spatial Distribution. as well as overall classification accuracy, users can understand the spatial distribution of misclassified pixels, and can have the additional criterion of the judgement on suitability and reliability of classification results.

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Gaussian Mixture Model using Minimum Classification Error for Environmental Sounds Recognition Performance Improvement (Minimum Classification Error 방법 도입을 통한 Gaussian Mixture Model 환경음 인식성능 향상)

  • Han, Da-Jeong;Park, Aa-Ron;Park, Jun-Qyu;Baek, Sung-June
    • The Journal of the Korea Contents Association
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    • v.11 no.12
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    • pp.497-503
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    • 2011
  • In this paper, we proposed the MCE as a GMM training method to improve the performance of environmental sounds recognition. We model the environmental sounds data with newly defined misclassification function using the log likelihood of the corresponding class and the log likelihood of the rest classes for discriminative training. The model parameters are estimated with the loss function using GPD(generalized probabilistic descent). For recognition performance comparison, we extracted the 12 degrees features using preprocessing and MFCC(mel-frequency cepstral coefficients) of the 9 kinds of environmental sounds and carry out GMM classification experiments. According to the experimental results, MCE training method showed the best performance by an average of 87.06% with 19 mixtures. This result confirmed us that MCE training method could be effectively used as a GMM training method in environmental sounds recognition.

HMM-based Upper-body Gesture Recognition for Virtual Playing Ground Interface (가상 놀이 공간 인터페이스를 위한 HMM 기반 상반신 제스처 인식)

  • Park, Jae-Wan;Oh, Chi-Min;Lee, Chil-Woo
    • The Journal of the Korea Contents Association
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    • v.10 no.8
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    • pp.11-17
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    • 2010
  • In this paper, we propose HMM-based upper-body gesture. First, to recognize gesture of space, division about pose that is composing gesture once should be put priority. In order to divide poses which using interface, we used two IR cameras established on front side and side. So we can divide and acquire in front side pose and side pose about one pose in each IR camera. We divided the acquired IR pose image using SVM's non-linear RBF kernel function. If we use RBF kernel, we can divide misclassification between non-linear classification poses. Like this, sequences of divided poses is recognized by gesture using HMM's state transition matrix. The recognized gesture can apply to existent application to do mapping to OS Value.