• Journal of Biosystems Engineering
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• v.23 no.3
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• pp.259-270
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• 1998

An automatic seedling transplanter, employed an innovative plug-seedling feeder was developed by improving the problems of conversational feeding and transplanting mechanisms. With conventional methods, missing and damage rates of seedling were high for long seedlings over 20cm and also breaking seed-bed was frequently observed. Thus, a pushout-bucket slide-hopper type trandsplanter was devised and tested. Test results of picking and transferring accuracies of the developed transplanter are as follows : A prototype transplanter performed with 1.5% of missing rate. The deviations of horizontal feed ranged from -0.3mm to 2.8mm and averaged 0.673mm for the 128-hoe test tray : and ranged from -lmm to ＋3mm and averaged 0.785mm for the 200-hole test tray. The deviations could decrease with precise manufacturing and lightening the mechanism. The maximum and deviations of vertical feed were -2.3mm and + 1mm, respectively, for the 128-hole test tray ; and were ＋3mm and ＋2.5mm, respectively, for the 200-hole test tray. The missing rate, seeding bruise rate and seed-bed damage rate were esitmate to be 1.3％, 0.4% and 3.5％, respectively, with the developed automatic transplanter.

• The Journal of the Acoustical Society of Korea
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• v.20 no.3
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• pp.56-62
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• 2001

In this paper, we adopt a missing data theory to speech recognition. It can be used in order to maintain high performance of speech recognizer when the missing data occurs. In general, hidden Markov model (HMM) is used as a stochastic classifier for speech recognition task. Acoustic events are represented by continuous probability density function in continuous density HMM(CDHMM). The missing data theory has an advantage that can be easily applicable to this CDHMM. A marginalization method is used for processing missing data because it has small complexity and is easy to apply to automatic speech recognition (ASR). Also, a spectral subtraction is used for detecting missing data. If the difference between the energy of speech and that of background noise is below given threshold value, we determine that missing has occurred. We propose a new method that examines the reliability of detected missing data using voicing probability. The voicing probability is used to find voiced frames. It is used to process the missing data in voiced region that has more redundant information than consonants. The experimental results showed that our method improves performance than baseline system that uses spectral subtraction method only. In 452 words isolated word recognition experiment, the proposed method using the voicing probability reduced the average word error rate by 12％ in a typical noise situation.

• Journal of Korean society of Dental Hygiene
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• v.15 no.6
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• pp.947-961
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• 2015

Objectives: The purpose of the study was to identify the relationship between metabolic syndrome and oral diseases in the middle aged and elderly in Korea. Methods: The study subjects were 6,390 people over 40 years old from 2010 and 2012 Korea National Health and Nutrition Examination Survey. The survey questionnaire consisted of health, nutrition, and oral examination surveys. The independent variables included general characteristics, health behavior, oral health behavior, and metabolic syndrome. The dependent variables included dental caries experience and periodontal disease. The oral examination was carried out by the dentist based on World Health Organization standard. Results: The average prevalence rate of metabolic syndrome MS was 23.79%, including 54.84% of risk group and 21.37% of normal group. The missing teeth rate was 82.38%, DMFT rate was 90.28% and the periodontal disease rate was 33.15%. Those having abnormal fasting blood glucose had 1.17 fold(95% CI: 1.00~1.37) higher periodontal disease than the normal group. The abnormal HDL cholesterol group had 1.25 times higher odds ratio(95% CI: 1.07~1.46) and the obese group had 1.27 times higher odds ratio(95% CI: 1.07~1.51). The risk group had 1.20 times higher odds ration(95% CI: 1.00~1.44) and that of the metabolic syndrome group was 1.60 times higher(95% CI: 1.29~1.97) in periodontal disease. The high blood pressure group had 1.25 times of missing teeth prevalence rate(95% CI: 1.00~1.37). The metabolic syndrome group had 1.47 times of missing teeth prevalence rate(95% CI: 1.11~1.94). Conclusions: The middle aged and elderly people in Korea had higher rate of metabolic syndrome and oral disease. It is necessary to implement the preventive oral health examination for the control of metabolic syndrome and oral diseases prevalence.

• Journal of Periodontal and Implant Science
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• v.36 no.3
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• pp.639-651
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• 2006

This study was performed to investigate the survival rate of single implant used in maxillary anterior region during follow up periods. 231 patients whose single missing tooth in maxillary region had been replaced with 237 implant at the periodontal dept. of Yonsei University Hospital between February 1993 and December 2004. The following results are compiled from 231 patients who received single implant surgery. 1. The major cause of single tooth loss in maxillary anterior region is trauma, followed by periodontal disease and congenital missing. 2. The total survival rate of single implant placed in maxillary anterior region is 94.5%. 3. The survival rate of single implant placed in type II and type IV was 100% and in type III was 92.7%. As for the bone quantity, the survival rate in type A(100%) was most, followed by type B(97.3%) and type C, D (93.5%). 4. The survival rate of implant placement combined with advanced surgery was 94.4%. The results showed that the placement of single implant is considered as a reliable treatment option for a single missing tooth in maxillary anterior region except in certain extreme conditions especially with poor bone quality and quantity.

• Journal of KIISE:Software and Applications
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• v.32 no.2
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• pp.99-107
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• 2005

In this paper, wc propose a now missing imputation method for minimizing loss of information linkage disequilibrium-based and haplotype-based imputation method, which estimate missing values of the data based on the specificity of Single Nucleotide Polymorphism(SNP) genotype data. Method for imputing data is needed to minimize the loss of information caused by experimental missing data. In general, missing imputation of biological data has used major allele imputation method. but this approach is not optima]. 1'his method has high error rates of missing values estimation since the characteristics of the genotype data are not considered not take into consideration the specific structure of the data. In this paper, we show the results of the comparative evaluation of our model methods and major imputation method for the estimation of missing values.

• Communications for Statistical Applications and Methods
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• v.28 no.5
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• pp.447-462
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• 2021

In insurance, the surrender rate is an important variable that threatens the sustainability of insurers and determines the profitability of the contract. Unlike other actuarial assumptions that determine the cash flow of an insurance contract, however, it is characterized by endogenous variables such as people's economic, social, and subjective decisions. Therefore, a microscopic approach is required to identify and analyze the factors that determine the lapse rate. Specifically, micro-level characteristics including the individual, demographic, microeconomic, and household characteristics of policyholders are necessary for the analysis. In this study, we select panel survey data of Korean Retirement Income Study (KReIS) with many diverse dimensions to determine which variables have a decisive effect on the lapse and apply the lasso regularized regression model to analyze it empirically. As the data contain many missing values, they are imputed using the random forest method. Among the household variables, we find that the non-existence of old dependents, the existence of young dependents, and employed family members increase the surrender rate. Among the individual variables, divorce, non-urban residential areas, apartment type of housing, non-ownership of homes, and bad relationship with siblings increase the lapse rate. Finally, among the financial variables, low income, low expenditure, the existence of children that incur child care expenditure, not expecting to bequest from spouse, not holding public health insurance, and expecting to benefit from a retirement pension increase the lapse rate. Some of these findings are consistent with those in the literature.

• Communications for Statistical Applications and Methods
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• v.19 no.1
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• pp.157-168
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• 2012

The EM algorithm is the most important tool to obtain the maximum likelihood estimator in finite mixture models due to its stability and simplicity. However, its convergence rate is often slow because the conventional EM algorithm is based on a large missing data space. Several techniques have been proposed in the literature to reduce the missing data space. In this paper, we review existing methods and propose a new EM algorithm for Gaussian mixtures, which reduces the missing data space while preserving the stability of the conventional EM algorithm. The performance of the proposed method is evaluated with other existing methods via simulation studies.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.3
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• pp.1469-1472
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• 2016

Cancer pathology reports play an important role in choice of patient care. They provide crucial information concerning diagnosis, therapy options, and prognosis. Professional pathology institutions, such as the College of American Pathologists (CAP), have developed checklists to ensure the presence of all the required elements in reports. In this study, 438 surgical pathology reports of patients with breast (148), colon (147), and stomach cancer (143) were evaluated with respect to the presence of mandated elements according to CAP checklists. The most common missing element in all the three types of cancer was 'staging' (73.6, 53.1, and 56.6% in breast, colon, and stomach cancer reports missed 'staging', respectively). The second most missing element was 'tumor site' in breast (64.2%) and stomach cancer (30.1%), and 'procedure' in colon cancer (29.3%). 'Perineural invasion' was the third most missing element in the three types of cancer (25.7, 17.0, and 22.4% in breast, colon, and stomach cancer, respectively). Only 11.4% of reports included all key elements required by CAP. The use of checklists was associated with higher rate of completeness. This study demonstrates that the key elements requiring the information on the requisition forms from the clinicians are commonly missed, leading to ambiguity.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.52 no.3
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• pp.241-247
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• 2016

The trawl fishery is an important fishery accounting for around 30.0% of adjacent water fishery production in Korea, and the commercial fishing is associated with high rate of fatal and non-fatal occupational injury. The hazard analysis for the fishermen's safety of offshore trawler was conducted to serve as basic data for improving the healthy and safe working environment of fishermen using fishermen's occupational accidents of the national federation of fisheries cooperatives (NFFC) from 2012 to 2014 (n=464). As a result, the occupational accident occurrence rate of large powered trawl fishery was 241.4‰ in east sea trawl fishery, 6.9 times the rate of that. In addition, death and missing rate was found to have very serious level management to 97.7‱ in east sea trawl fishery of death at 6.2 times. The accident occurred in 91.7 to 100.0% was happened at sea. The slipping, others and struck by object and son on occurred more frequently in order in the frequency of accident occurrence pattern. However, the occurrence rate of death and missing did not match the frequency of accident pattern. In other words, slipping occurred more frequently while death and missing risk was not high. The fall in the waters was low while death and missing risk was high. The results are expected to help identify and assess safety hazard occurred in offshore trawlers.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.51 no.2
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• pp.188-194
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• 2015

The powered purse seine fishery is an important fishery accounting for 19.4% of adjacent water fishery production in Korea, and the commercial fishing is associated with high rate of fatal and non-fatal occupational injury. The hazard analysis for the fishermen's safety of offshore large powered purse seiner was conducted to serve as a basic data for improving the healthy and safe working environment of fishermen using fishermen's occupational accidents of the national federation of fisheries cooperatives (NFFC) in 2013 (n=583). As a result, the occupational accident occurrence rate of this fishery was 182.6‰ in all industries 30.9 times the rate of that. In addition, death and missing rate was found to have a very serious level management to 25.1‰ in all industries of death of 17.5 times. The accident occurred in 72.3 to 85.8% was happened at sea. The others, slipping and struck by object etc occurred more frequently in order in the frequency of accident occurrence pattern. However, the occurrence rate of death and missing did not match the frequency of accident pattern. In other words, slipping occurred frequently higher while death and missing risk was not high. And the contact with fishing gear and fall in the waters was low while death and missing risk was high. The results are expected to contribute for identification and assessment of safety hazard occurred in offshore large powered purse seiners.