• Journal of the Korea Society for Simulation
• /
• v.23 no.4
• /
• pp.203-210
• /
• 2014

This study proposes adaptive decision making method having feed-back structure of regression and simulation models to support the quick decision making of production managers by managing and integrating the mutual relationship among historical data. For that, from historical data that have extracted and accumulated from each process, we first selected major constraint resources that are used as independent variables in regression model. The regression model is designed by using the dependent variables (objectives) that defined above by managers and independent variables selected in previous step and simulation model that are composed of constraint resources is designed. In process of simulation run, we obtain the multiple feasible solutions (alternatives) by using meta-heuristic method. Each solution is substituted by regression equation and we found the optimal solution that is minimum of difference between values obtained by regression model and simulation results. The optimal solution is delivered and incorporated to production site and current operation results from production site is used to generate new regression model after that time.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.21 no.4
• /
• pp.520-528
• /
• 2018

This paper studies the optimal inventory levels of Korea Assault Amphibious Vehicle(KAAV)'s assemblies in order to assure the required operational availability. The simulation model is built and implemented for the impact of the inventory levels on operational availability. Using regression analysis and integer programming, the optimal inventory levels of essential assemblies are suggested and analyzed. Finally, sensitivity analysis is conducted with recycling maintenance delay time.

• Journal of Korean Society for Quality Management
• /
• v.38 no.3
• /
• pp.333-339
• /
• 2010

It is difficult to determine an optimal inventory level of aircraft engine and modules to achieve the target operational availability since F100-PW-200 & 229 engines of the F-16 & KF-16 aircraft are consisted of 5 modules with different failure rates and costs. This study presents a decision model, combining an integer programming problem and a regression metamodel. Data for the metamodel was attained from results of a simulation model, that represents operational and repair process of F-16 and KF-16. The objective function of an integer programming problem is maximizing the operational availability, representing pessimistic circumstances. Finally, an integer programming problem with a metamodel can make an optimal decision of the inventory level.

• Journal of the Korea Society for Simulation
• /
• v.14 no.3
• /
• pp.43-54
• /
• 2005

For the effective design of automated distribution center composed of Automated Storage/Retrieval System, Automated Guided Vehicle System, and Conveyor System, we proposed an analysis method to determining. design and control parameters with multiple performance objectives using Compromise Programming, which can resolve the dilemma of conflicting objectives. The Evolution Strategy generates the optimal solutions for each objectives. The Analytic Hierarchy Process selects the best solution among the alternatives generated from Evolution Strategy. The Regression Analysis formulates the objective functions for each objectives. By reducing deviations between goal values and target values generated from Analytic Hierarchy Process, Compromise Programming determines design and control parameters by compromising the multiple objectives formulated using Regression Analysis. When the parameters of system are changed, this proposed analysis method has a benefit of reducing costs and time without repeating whole simulation run.

• Physical Therapy Korea
• /
• v.31 no.2
• /
• pp.91-103
• /
• 2024

Stroke is one of the most common disabilities experienced by the elderly in the community. However, stroke progresses to a chronic level, patients are discharged from medical institutions and eventually no longer receive therapeutic interventions at home. In this systematic review, we compared home-based rehabilitation (HBR) with comparison for patients with stroke. Literature published in Cumulative Index for Nursing and Allied Health Literature (CINAHL), Embase, Physiotherapy Evidence Database (PEDro), PubMed, and Google Scholar were reviewed. A total of 1,158 studies were initially retrieved. After reading the full texts, 11 articles were included in the systematic review. Quality assessment of the included studies was conducted using Risk of Bias (RoB) 2.0, and Egger's regression test was used to evaluate publication bias. Data analysis was performed using the R studio software (R Studio). According to the quality assessment using RoB 2.0, three studies were evaluated as low risk, two as of some concern, and three as high risk. The overall effect size was moderate (0.309). The value of the balance function was a small effect size (0.201), while the value of the gait function was a moderate effect size (0.353). The values were small and moderate effect (0.154, 0.411) for the chronic and subacute conditions, respectively. According to the Egger's regression test, no publication bias was observed. The findings of this study indicate that HBR resulted in the greatest improvement in gait function in patients with subacute stroke compared to those with chronic stroke. Therefore, the application of this intervention to patients with stroke in the community is recommended.

• Advances in nano research
• /
• v.13 no.5
• /
• pp.499-512
• /
• 2022

This study investigates the efficiency of ensemble machine learning for predicting the lightweight-aggregate concrete (LWC) characteristics. A stacking ensemble (STEN) approach was proposed to estimate the dry density (DD) and 28 days compressive strength (Fc-28) of LWC using two meta-models called random forest regressor (RFR) and extra tree regressor (ETR), and two novel ensemble models called STEN-RFR and STEN-ETR, were constructed. Four standalone machine learning models including artificial neural network, gradient boosting regression, K neighbor regression, and support vector regression were used to compare the performance of the proposed models. For this purpose, a sum of 140 LWC mixtures with 21 influencing parameters for producing LWC with a density less than 1000 kg/m³, were used. Based on the experimental results with multiple performance criteria, it can be concluded that the proposed STEN-ETR model can be used to estimate the DD and Fc-28 of LWC. Moreover, the STEN-ETR approach was found to be a significant technique in prediction DD and Fc-28 of LWC with minimal prediction error. In the validation phase, the accuracy of the proposed STEN-ETR model in predicting DD and Fc-28 was found to be 96.79% and 81.50%, respectively. In addition, the significance of cement, water-cement ratio, silica fume, and aggregate with expanded glass variables is efficient in modeling DD and Fc-28 of LWC.

• The Journal of Korean Medicine
• /
• v.42 no.4
• /
• pp.222-237
• /
• 2021

Objectives: The purpose of this study was to investigate the trend in the research on cirrhotic ascites using t herbal medicine. Methods: This review was conducted using six electronic databases(NDSL, KMBASE, Koreantk, KISS, KISTI, KoreaMed) with no restriction in year. The search term was 'liver cirrhosis', 'ascites', or 'cirrhotic ascites', 'herbal medicine', 'traditional Chinese medicine', and 'randomized clinical trial', and there was no restriction in year. The searched studies were analyzed according to the type of research. Results: After scanning the titles and abstracts, 13 articles were ultimately included. Of the outcome measures of 13 studies, effective rate, liver function test, and ascites regression time were included in the meta-analysis, which showed that the effective rate of herbal medicine-supportive treatment combination therapy was 1.27 times higher than that of supportive treatment alone, and the difference was statistically significant. Conclusions: We analyzed the trends of cirrhotic ascites treatment in herbal medicine through this review. It is necessary to conduct further studies, such as well-designed clinical trials based on the results from experimental research.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.8
• /
• pp.429-439
• /
• 2020

This study examined the effect size of virtual reality programs on the upper extremity function of stroke patients through a meta-analysis. Databases, such as the Research Information Sharing Service, the Korean Studies Information Service System, the National Library of Korea, the Korean Citation Index, and the National Digital Science Library, were used. Previous articles were surveyed for virtual reality programs between January 2010 and June 2019. A meta-analysis was performed by selecting the final 14 studies based on the PICO standard. The RoB and RoBANS tools were used as quality assessment tools for randomized and non-randomized control trials, respectively. The CMA 3.0 program was used to calculate the effect size of each study. Sub-group analysis, meta-regression analysis, and publication bias were performed. The total effect size of the virtual reality programs on the upper extremity function was Hedges's g=0.390 (95% CI: 0.192~0.587) (p<.05). The virtual reality program positively affects the upper extremity function of stroke patients. Therefore, the development of various virtual reality programs and industry-academia cooperation technology for stroke patients is required in accordance with the fourth industry. Randomized control trials and detailed upper extremity function studies for virtual reality programs will be needed in follow-up studies.

• Asian Pacific Journal of Cancer Prevention
• /
• v.14 no.3
• /
• pp.1615-1621
• /
• 2013

Background: Matrix metalloproteinase 9 (MMP-9) is related to tumor invasion and metastasis. However, the role of MMP-9 expression in breast cancer survival remains controversial. The purpose of this study was to accomplish a more accurate estimation of the association between MMP-9 expression and survival results in breast cancer patients through meta-analysis. Methods: A meta-analysis of published studies investigating the effects of positive MMP-9 expression on both relapse free survival (RFS) and overall survival (OS) was performed. Relevant literature was confirmed by searching electronic databases including PubMed, Ovid, EMBASE and China National Knowledge Infrastructure (CNKI) before November 1, 2012. Individual hazard ratios (HRs) and 95% confidence intervals (CIs) were extracted and pooled HRs with 95% CIs were used to evaluate the strength of the association between positive MMP-9 expression and survival results of breast cancer patients. Funnel plot and Egger's regression tests were used to evaluate publication bias. Heterogeneity and sensitivity analysis was also conducted. All the work was completed using STATA. Results: A total of 2,344 patients from 15 evaluative studies were finally included. Pooled HRs and 95% CIs suggested that MMP-9 overexpression had an unfavorable impact on both OS (HR: 1.70, 95% CI: 1.41-2.04) and RFS (HR: 1.54, 95% CI: 1.17-2.01) in breast cancer patients. There was no significant heterogeneity observed in the studies reported for OS (P=0.360, $I^2$=8.8%), but not RFS (P=0.002, $I^2$=67%). Publication bias was absent among the studies both in OS and RFS cases (t=-0.54, P=0.605 and t=1.71, P=0.131, respectively). Omission of any single study had little effect on the combined risk estimates on sensitivity analysis. Conclusion: The results of this meta-analysis suggest that positive MMP-9 expression confers a higher risk of relapse and a worse survival in patients with breast cancer. Larger prospective studies are now needed to evaluate the clinical utility of MMP-9 expression.

• Asian Pacific Journal of Cancer Prevention
• /
• v.16 no.8
• /
• pp.3485-3491
• /
• 2015

Background: Nodal invasion by colorectal cancer is a critical determinant in estimating patient survival and in choosing appropriate preoperative treatment. The present meta-analysis was designed to evaluate the diagnostic value of endorectal ultrasound (EUS) in preoperative assessment of lymph node involvement in colorectal cancer. Materials and Methods: We systematically searched PubMed, Web of Science, Embase, and China National Knowledge Infrastructure (CNKI) databases for relevant studies published on or before December 10th, 2014. The sensitivity, specificity, likelihood ratios, diagnostic odds ratio (DOR) and area under the summary receiver operating characteristics curve (AUC) were assessed to estimate the diagnostic value of EUS. Subgroup analysis and meta-regression were performed to explore heterogeneity across studies. Results: Thirty-three studies covering 3,016 subjects were included. The pooled sensitivity and specificity were 0.69 (95%CI: 0.63-0.75) and 0.77 (95%CI: 0.73-0.82), respectively. The positive and negative likelihood ratios were 3.09 (95%CI: 2.52-3.78) and 0.39 (95%CI: 0.32-0.48), respectively. The DOR was 7.84 (95%CI: 5.56-11.08), and AUC was 0.80 (95%CI: 0.77-0.84). Conclusions: This meta-analysis indicated that EUS has moderate diagnostic value in preoperative assessment of lymph node involvement in colorectal cancer. Further refinements in technology and diagnostic criteria are necessary to improve the diagnostic accuracy of EUS.