• Title/Summary/Keyword: bayesian

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Prospective validation of a novel dosing scheme for intravenous busulfan in adult patients undergoing hematopoietic stem cell transplantation

  • Cho, Sang-Heon;Lee, Jung-Hee;Lim, Hyeong-Seok;Lee, Kyoo-Hyung;Kim, Dae-Young;Choe, Sangmin;Bae, Kyun-Seop;Lee, Je-Hwan
    • The Korean Journal of Physiology and Pharmacology
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    • v.20 no.3
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    • pp.245-251
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    • 2016
  • The objective of this study was to externally validate a new dosing scheme for busulfan. Thirty-seven adult patients who received busulfan as conditioning therapy for hematopoietic stem cell transplantation (HCT) participated in this prospective study. Patients were randomized to receive intravenous busulfan, either as the conventional dosage (3.2 mg/kg daily) or according to the new dosing scheme based on their actual body weight (ABW) ($23{\times}ABW^{0.5}mg\;daily$) targeting an area under the concentration-time curve (AUC) of $5924{\mu}M{\cdot}min$. Pharmacokinetic profiles were collected using a limited sampling strategy by randomly selecting 2 time points at 3.5, 5, 6, 7 or 22 hours after starting busulfan administration. Using an established population pharmacokinetic model with NONMEM software, busulfan concentrations at the available blood sampling times were predicted from dosage history and demographic data. The predicted and measured concentrations were compared by a visual predictive check (VPC). Maximum a posteriori Bayesian estimators were estimated to calculate the predicted AUC ($AUC_{PRED}$). The accuracy and precision of the $AUC_{PRED}$ values were assessed by calculating the mean prediction error (MPE) and root mean squared prediction error (RMSE), and compared with the target AUC of $5924{\mu}M{\cdot}min$. VPC showed that most data fell within the 95% prediction interval. MPE and RMSE of $AUC_{PRED}$ were -5.8% and 20.6%, respectively, in the conventional dosing group and -2.1% and 14.0%, respectively, in the new dosing scheme group. These findings demonstrated the validity of a new dosing scheme for daily intravenous busulfan used as conditioning therapy for HCT.

Survey of genetic structure of geese using novel microsatellite markers

  • Lai, Fang-Yu;Tu, Po-An;Ding, Shih-Torng;Lin, Min-Jung;Chang, Shen-Chang;Lin, En-Chung;Lo, Ling-Ling;Wang, Pei-Hwa
    • Asian-Australasian Journal of Animal Sciences
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    • v.31 no.2
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    • pp.167-179
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    • 2018
  • Objective: The aim of this study was to create a set of microsatellite markers with high polymorphism for the genetic monitoring and genetic structure analysis of local goose populations. Methods: Novel microsatellite markers were isolated from the genomic DNA of white Roman geese using short tandem repeated probes. The DNA segments, including short tandem repeats, were tested for their variability among four populations of geese from the Changhua Animal Propagation Station (CAPS). The selected microsatellite markers could then be used to monitor genetic variability and study the genetic structures of geese from local geese farms. Results: 14 novel microsatellite loci were isolated. In addition to seven known loci, two multiplex sets were constructed for the detection of genetic variations in geese populations. The average of allele number, the effective number of alleles, the observed heterozygosity, the expected heterozygosity, and the polymorphism information content were 11.09, 5.145, 0.499, 0.745, and 0.705, respectively. The results of analysis of molecular variance and principal component analysis indicated a contracting white Roman cluster and a spreading Chinese cluster. In white Roman populations, the CAPS populations were depleted to roughly two clusters when K was set equal to 6 in the Bayesian cluster analysis. The founders of private farm populations had a similar genetic structure. Among the Chinese geese populations, the CAPS populations and private populations represented different clads of the phylogenetic tree and individuals from the private populations had uneven genetic characteristics according to various analyses. Conclusion: Based on this study's analyses, we suggest that the CAPS should institute a proper breeding strategy for white Roman geese to avoid further clustering. In addition, for preservation and stable quality, the Chinese geese in the CAPS and the aforementioned proper breeding scheme should be introduced to geese breeders.

Intercomparison of Change Point Analysis Methods for Identification of Inhomogeneity in Rainfall Series and Applications (강우자료의 비동질성 규명을 위한 변동점 분석기법의 상호비교 및 적용)

  • Lee, Sangho;Kim, Sang Ug;Lee, Yeong Seob;Sung, Jang Hyun
    • Journal of Korea Water Resources Association
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    • v.47 no.8
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    • pp.671-684
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    • 2014
  • Change point analysis is a efficient tool to understand the fundamental information in hydro-meteorological data such as rainfall, discharge, temperature etc. Especially, this fundamental information to change points to future rainfall data identified by reasonable detection skills can affect the prediction of flood and drought occurrence because well detected change points provide a key to resolve the non-stationary or inhomogeneous problem by climate change. Therefore, in this study, the comparative study to assess the performance of the 3 change point detection skills, cumulative sum (CUSUM) method, Bayesian change point (BCP) method, and segmentation by dynamic programming (DP) was performed. After assessment of the performance of the proposed detection skills using the 3 types of the synthetic series, the 2 reasonable detection skills were applied to the observed and future rainfall data at the 5 rainfall gauges in South Korea. Finally, it was suggested that BCP (with 0.9 posterior probability) could be best detection skill and DP could be reasonably recommended through the comparative study. Also it was suggested that BCP (with 0.9 posterior probability) and DP detection skills to find some change points could be reasonable at the North-eastern part in South Korea. In future, the results in this study can be efficiently used to resolve the non-stationary problems in hydrological modeling considering inhomogeneity or nonstationarity.

Development and application of GLS OD matrix estimation with genetic algorithm for Seoul inner-ringroad (유전알고리즘을 이용한 OD 추정모형의 개발과 적용에 관한 연구 (서울시 내부순환도로를 대상으로))

  • 임용택;김현명;백승걸
    • Journal of Korean Society of Transportation
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    • v.18 no.4
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    • pp.117-126
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    • 2000
  • Conventional methods for collecting origin-destination trips have been mainly relied on the surveys of home or roadside interview. However, the methods tend to be costly, labor intensive and time disruptive to the trip makers, thus the methods are not considered suitable for Planning applications such as routing guidance, arterial management and information Provision, as the parts of deployments in Intelligent Transport Systems Motivated by the problems, more economic ways to estimate origin-destination trip tables have been studied since the late 1970s. Some of them, which have been estimating O-D table from link traffic counts are generally Entropy maximizing, Maximum likelihood, Generalized least squares(GLS), and Bayesian inference estimation etc. In the Paper, with user equilibrium constraint we formulate GLS problem for estimating O-D trips and develop a solution a1gorithm by using Genetic Algorithm, which has been known as a g1oba1 searching technique. For the purpose of evaluating the method, we apply it to Seoul inner ringroad and compare it with gradient method proposed by Spiess(1990). From the resu1ts we fond that the method developed in the Paper is superior to other.

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Comparison of Dynamic Origin Destination Demand Estimation Models in Highway Network (고속도로 네트워크에서 동적기종점수요 추정기법 비교연구)

  • 이승재;조범철;김종형
    • Journal of Korean Society of Transportation
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    • v.18 no.5
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    • pp.83-97
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    • 2000
  • The traffic management schemes through traffic signal control and information provision could be effective when the link-level data and trip-level data were used simultaneously in analysis Procedures. But, because the trip-level data. such as origin, destination and departure time, can not be obtained through the existing surveillance systems directly. It is needed to estimate it using the link-level data which can be obtained easily. Therefore the objective of this study is to develop the model to estimate O-D demand using only the link flows in highway network as a real time. The methodological approaches in this study are kalman filer, least-square method and normalized least-square method. The kalman filter is developed in the basis of the bayesian update. The normalized least-square method is developed in the basis of the least-square method and the natural constraint equation. These three models were experimented using two kinds of simulated data. The one has two abrupt changing Patterns in traffic flow rates The other is a 24 hours data that has three Peak times in a day Among these models, kalman filer has Produced more accurate and adaptive results than others. Therefore it is seemed that this model could be used in traffic demand management. control, travel time forecasting and dynamic assignment, and so forth.

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CLINICAL STUDY OF POSITRON EMISSION TOMOGRAPHY WITH $[^{18}F]$-FLUORODEOXYGLUCOSE IN MAXILLOFACIAL TUMOR DIAGNOSIS (구강 악안면 영역의 암종 진단에 있어서 $[^{18}F]$-Fluorodeoxyglucose를 이용한 양전자방출 단층촬영의 임상적 연구)

  • Kim, Jae-Hwan;Kim, Kyung-Wook;Kim, Yong-Kack
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • v.26 no.5
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    • pp.462-469
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    • 2000
  • Positron Emission Tomography(PET) is a new diagnostic method that can create functional images of the distribution of positron emitting radionuclides, which when administered intravenously in the body, makes possible anatomical and functional analysis by quantity of biochemical and physiological process. After genetic and biochemical changes in initial stage, malignant tumor undergoes functional changes before undergoing anatomical changes. So, early diagnosis of malignant tumors by functional analysis with PET can be achieved, replacing traditional anatomical analysis, such as computed tomography(CT) and magnetic resonance image(MRI), etc. Similarly, PET can identify malignant tumor without confusion with scar and fibrosis in follow up check. In the Korea Cancer Center Hospital(KCCH) from October 1997 to September 1999, clinical study was performed in 79 cases that underwent 89 times PET evaluation with [18F]-Fluorodeoxyglucose for diagnosis of oral and maxillofacial tumors, and the data was analysed by Bayesian $2{\times}2$ Classification Table. The results were as follows : Evaluation for initial diagnosis with FDG-PET (P<0.005) 1. Agreement rate or accuracy rate is 88.9%. 2. Sensitivity is 95.2%, and specificity 66.7%. 3. Positive predictive rate is 90.9%, and negative predictive rate 80.0%. 4. In consideration of tumor stage, diagnostic rate in less than stage II was 90% and in greater than stage III 100%. 5. In consideration of tumor size, diagnostic rate in less than T2 was 92.3% and in greater than T3 100%. After primary treatment, evaluation for follow up check with FDG-PET (P < 0.001) 1. Agreement rate or accuracy rate is 85.4%. 2. Sensitivity is 87.5%, and specificity 82.4%. 3. Positive predictive rate is 87.5%, and negative predictive rate 82.4%. 4. In 24 recurred cases, 6 had distant metastasis, and 5 of them were diagnosed with FDG-PET, resulting in diagnostic rate of FDG-PET of 83.3%. From the above results, Positron Emission Tomography with [18F]- Fluorodeoxyglucose appears to be more sensitive and accurate for detecting the presence of oral and maxillofacial tumors, and has various clinical applications such as early diagnosis of tumor in initial and follow up check and detection of distant metastasis.

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Refinement of damage identification capability of neural network techniques in application to a suspension bridge

  • Wang, J.Y.;Ni, Y.Q.
    • Structural Monitoring and Maintenance
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    • v.2 no.1
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    • pp.77-93
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    • 2015
  • The idea of using measured dynamic characteristics for damage detection is attractive because it allows for a global evaluation of the structural health and condition. However, vibration-based damage detection for complex structures such as long-span cable-supported bridges still remains a challenge. As a suspension or cable-stayed bridge involves in general thousands of structural components, the conventional damage detection methods based on model updating and/or parameter identification might result in ill-conditioning and non-uniqueness in the solution of inverse problems. Alternatively, methods that utilize, to the utmost extent, information from forward problems and avoid direct solution to inverse problems would be more suitable for vibration-based damage detection of long-span cable-supported bridges. The auto-associative neural network (ANN) technique and the probabilistic neural network (PNN) technique, that both eschew inverse problems, have been proposed for identifying and locating damage in suspension and cable-stayed bridges. Without the help of a structural model, ANNs with appropriate configuration can be trained using only the measured modal frequencies from healthy structure under varying environmental conditions, and a new set of modal frequency data acquired from an unknown state of the structure is then fed into the trained ANNs for damage presence identification. With the help of a structural model, PNNs can be configured using the relative changes of modal frequencies before and after damage by assuming damage at different locations, and then the measured modal frequencies from the structure can be presented to locate the damage. However, such formulated ANNs and PNNs may still be incompetent to identify damage occurring at the deck members of a cable-supported bridge because of very low modal sensitivity to the damage. The present study endeavors to enhance the damage identification capability of ANNs and PNNs when being applied for identification of damage incurred at deck members. Effort is first made to construct combined modal parameters which are synthesized from measured modal frequencies and modal shape components to train ANNs for damage alarming. With the purpose of improving identification accuracy, effort is then made to configure PNNs for damage localization by adapting the smoothing parameter in the Bayesian classifier to different values for different pattern classes. The performance of the ANNs with their input being modal frequencies and the combined modal parameters respectively and the PNNs with constant and adaptive smoothing parameters respectively is evaluated through simulation studies of identifying damage inflicted on different deck members of the double-deck suspension Tsing Ma Bridge.

Report of the 3rd Japan-Korea Workshop on Acupuncture and EBM;Protocol development for the acupuncture trial on the osteoarthritis of the knee

  • Jang, Jun-Hyouk;Kenji, Kawakita;Hahn, Seo-Kyung;Park, Hi-Joon;Lee, Seung-Deok;Kim, Yong-Suk;Norihito, Takahashi;Toshiyuki, Shichidou;Kazunori, Itoh;Eiji, Sumiya;Eiji, Furuya;Hitoshi, Yamashita;Hiroshi, Tsukayama
    • Journal of Acupuncture Research
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    • v.23 no.6
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    • pp.239-254
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    • 2006
  • The 3rd Japan-Korea Workshop on Acupuncture and EBM was held at Kanazawa on June $16^{th}$. From Korea team, 4 papers were presented. Dr. Hahn introduced a new approach of data analysis on series of n-of-1 trials using the Bayesian statistics. It offered important information for the future n-of-1 trials. Dr. Park clearly demonstrated the significance of various sham devices proposed and stressed the importance of research questions when we choose the control intervention in RCT. Dr. Lee reported the results of survey in Korean Medical Doctors (KMD) for their point selection and techniques to the distal and local points. Dr. Kim presented the results of face to face survey on the KMD with 28 items for acupuncture treatment on the knee OA. Finally, a draft of protocol was introduced by Dr. Kim. The title was "multi-center, a randomized, single blinded, two arms, parallel-group study to compare the effectiveness and safety of 'individualized acupuncture' and 'standardized minimal acupuncture' in Korean and Japanese patients with knee osteoarthritis (Phase IV)". From Japan team, 7 speakers presented their comments and proposals on the protocol. Dr. Takahashi introduced several issues regarding n-of-1 trials and pointed out the importance of obtaining generalizability from n-of-1 trials. Dr. Shichidou pointed the importance of research design, selection of outcome measures and reduction of biases. Dr. Itoh presented the results of point selection for the knee OA based on the literature survey. Dr. Sumiya introduced several differences between KMD and Japanese acupuncturists based on the questionnaire used in KMD survey. Dr. Furuya demonstrated a result of press tack needle and its sham device on shoulder stiffness. Dr. Yamashita introduced the results of literature survey regarding adverse events occurred by acupuncture on knee OA. Dr.Tsukayama stressed the importance of responsibility of Institutional Review Board (IRB) for the conduction of clinical trials. After several issues were discussed, the need of continued meeting for final protocol development was agreed, then the workshop was closed.

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Human Gait-Phase Classification to Control a Lower Extremity Exoskeleton Robot (하지근력증강로봇 제어를 위한 착용자의 보행단계구분)

  • Kim, Hee-Young
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.39B no.7
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    • pp.479-490
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    • 2014
  • A lower extremity exoskeleton is a robot device that attaches to the lower limbs of the human body to augment or assist with the walking ability of the wearer. In order to improve the wearer's walking ability, the robot senses the wearer's walking locomotion and classifies it into a gait-phase state, after which it drives the appropriate robot motions for each state using its actuators. This paper presents a method by which the robot senses the wearer's locomotion along with a novel classification algorithm which classifies the sensed data as a gait-phase state. The robot determines its control mode using this gait-phase information. If erroneous information is delivered, the robot will fail to improve the walking ability or will bring some discomfort to the wearer. Therefore, it is necessary for the algorithm constantly to classify the correct gait-phase information. However, our device for sensing a human's locomotion has very sensitive characteristics sufficient for it to detect small movements. With only simple logic like a threshold-based classification, it is difficult to deliver the correct information continually. In order to overcome this and provide correct information in a timely manner, a probabilistic gait-phase classification algorithm is proposed. Experimental results demonstrate that the proposed algorithm offers excellent accuracy.

An estimation method for non-response model using Monte-Carlo expectation-maximization algorithm (Monte-Carlo expectation-maximaization 방법을 이용한 무응답 모형 추정방법)

  • Choi, Boseung;You, Hyeon Sang;Yoon, Yong Hwa
    • Journal of the Korean Data and Information Science Society
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    • v.27 no.3
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    • pp.587-598
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    • 2016
  • In predicting an outcome of election using a variety of methods ahead of the election, non-response is one of the major issues. Therefore, to address the non-response issue, a variety of methods of non-response imputation may be employed, but the result of forecasting tend to vary according to methods. In this study, in order to improve electoral forecasts, we studied a model based method of non-response imputation attempting to apply the Monte Carlo Expectation Maximization (MCEM) algorithm, introduced by Wei and Tanner (1990). The MCEM algorithm using maximum likelihood estimates (MLEs) is applied to solve the boundary solution problem under the non-ignorable non-response mechanism. We performed the simulation studies to compare estimation performance among MCEM, maximum likelihood estimation, and Bayesian estimation method. The results of simulation studies showed that MCEM method can be a reasonable candidate for non-response model estimation. We also applied MCEM method to the Korean presidential election exit poll data of 2012 and investigated prediction performance using modified within precinct error (MWPE) criterion (Bautista et al., 2007).