Leerojanaprapa, Kanogkan
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Preferred name
Leerojanaprapa, Kanogkan
Alternative Name
Leerojanaprapa, K.
Main Affiliation
Email
kanogkan.le@kmitl.ac.th
24 results
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Item type:Publication, Full-model regression sum of squares of randomized complete block design having one unrecorded observation(2019-01-01); ; Sirikasemsuk, SirisakIn the classical design of experiment, a randomized complete block design (RCBD) is a helpful experimental design because this design uses a small number of experimental units. The randomized complete block design is comprised of two factors, i.e., a nuisance factor and a potential factor. In many real experiments, some data might be missing or unrecorded. The instant formulae were not provided for an analysis of variance in this case. This paper took into account the randomized complete block design (RCBD) with a treatments and b blocks. In this contribution, the RCBD with an unrecorded value was analyzed by means of the exact scheme with the model comparison approach. The advantages of the exact scheme are that the unrecorded value for the unfilled cell is not estimated and the treatment sum of squares is unbiased. It is important to note that there is no ready-made formula for RCBD in the past. Hence, this research paper provided the mathematical formulae for the fitted parameters and the overall regression sum of squares (ORSS) for the full model of experimental data. It is also noted that the ORSS is imperative for the analysis of the variance by means of the exact scheme. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Optimization of Process Conditions for Hard Disk Drive Assembly for Defect Reduction(2023-11-01); A spoiler installed in a hard disk drive can reduce the airflow velocity that causes vibration at an actuator arm and its head. In the case study, a hard disk drive manufacturer identified the defect of a loosely tightened spoiler in the hard disk drive by the spoiler installation machine. This occurred as a result of incorrect screw spacing (also called ‘the screwdriver encoder’). There was no study that specifically specified or created a suitable relationship model between the screwdriver encoder and associated parameters for the installation of a spoiler. Factors affecting the screw spacing were determined using multiple regression analysis, and a mathematical model of the significant factors of the screwdriver encoder was built. Data were collected from the spoiler installation machine and its software. Four factors were identified with the potential to impact the screwdriver encoder as (1) vacuum level for picking up the screw, (2) time spent in tightening the screw, (3) bit angle, and (4) screw torque. The ANOVA results pointed out that the screw torque within the range of experimental values did not affect the screw spacing, and a quadratic regression model was the most appropriate under various statistical criteria. This research demonstrated that a sophisticated regression model, i.e., a cubic model, is not always a good choice for an agent. In addition, the optimal values for the spoiler installation machine were determined. The faults decreased by 0.0096% from 0.055% each month. For choosing the relationship model of additional workpiece screw tightening variables, this research phase can be utilized as a guideline. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Applying Bayesian network for noncommunicable diseases risk analysis: Implementing national health examination survey in Thailand(2017-07-02); - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Using DEMATEL to explore the relationship of factors affecting consumers' behaviors in buying green products(2018-01-01) - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Solving the incomplete data problem in Greco-Latin square experimental design by exact-scheme analysis of variance without data imputation(2024-01-01); - Some of the metrics are blocked by yourconsent settings
Item type:Publication, One missing value problem in Latin square design of any order: Exact analysis of variance(2017-01-01); This research proposes a simplified exact approach based on the general linear model for solving the K × K Latin square design (LSD) with one replicate and one missing value, given the lack of ready-made mathematical formulas for the sub-variance. Under the proposed scheme, the effects of the potential variable were determined by means of the regression sums of squares under the full and reduced treatment models. The mathematical expressions could be applied to the LSD with one missing value of any order. Moreover, the treatment, row and column sums of squares are unbiased. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Comparison of Bayesian Networks for Diabetes Prediction(2019-01-01); A Bayesian network (BN) can be used to predict the prevalence of diabetes from the cause–effect relationship among risk factors. By applying a BN model, we can capture the interdependencies between direct and indirect risks hierarchically. In this study, we propose to investigate and compare the predictive performances of BN models with non-hierarchical (BNNH), and non-hierarchical and reduced variables (BNNHR) structures, hierarchical structure by expert judgment (BNHE), and hierarchical learning structure (BNHL) with type-2 diabetes. ROC curves, AUC, percentage error, and F1 score were applied to compare performances of those classification techniques. The results of the model comparison from both datasets (training and testing) obtained from the Thai National Health Examination Survey IV ensured that BNHE can predict the prevalence of diabetes most effectively with the highest AUC values of 0.7670 and 0.7760 from the training and the testing dataset, respectively. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Factors associated with Thai exporter's interest in using New Dawei deep seaport(2017-01-01); ; Bhundarak, KomnDawei deep seaport in a part of the Dawei Special Economic Zone (Dawei SEZ) in Myanmar aims to support the new economics along the GMS Southern Corridor. The Dawei seaport can serve the potential new industries along the new industry zones. The new port will be the alternative route for Thai exporters in the future as it is under construction. The exploratory study by employing survey was selected and analyzed to identify the significant influencing factors. The results of hypothesis testing by Pearson Chi-Square test confirm the relation between the interest of using new Dawei deep seaport and the location of manufacturer (p-value = 0.027). In addition, the results of t-test confirm the significant six decision variables of Time for transportation (v7), Reliability of service (v10), Port size and capability (v15), Facility (v25), Professionals and skilled labors in port operation (v30), and Port accessibility (v31) are more important for exporters who are interested in Dawei seaport than the exporters who may not be intend to use the new seaport, p-value (1-tailed) < 0.05. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Navigating online learning challenges and educational infrastructure in times of crisis: Insights and solutions among Thai engineering students utilizing a mixed-methods analysis(2024-01-01); ; The rapid shift to online learning during COVID-19 posed challenges for students. This investigation explored these hurdles and suggested effective solutions using mixed methods. By combining a literature review, interviews, surveys, and the analytic hierarchy process (AHP), the study identified five key challenges: lack of practical experience, disruptions in learning environments, condensed assessments, technology and financial constraints, and health and mental well-being concerns. Notably, it found differences in priorities among students across academic years. Freshmen struggled with the absence of hands-on courses, sophomores with workload demands, and upperclassmen with mental health challenges. The research also discussed preferred strategies for resolution, emphasizing independent learning methods, managing distractions, and adjusting assessments. By providing tailored insights, this study aimed to enhance online learning. Governments and universities should support practical work, prioritize student well-being, improve digital infrastructure, adapt assessments, foster innovation, and ensure resilience. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Management practices of Thai silk product(2015-01-01); Atthirawong, WalailakThai silk is one of Thailand’s most well-known products, which is considered as the best silk in the world. It is famous for its bearing uniqueness features, beautiful designs, bright colors and elegant quality. Silk weaving is a long-established folk craft passed down from generation to generation that resembles the region’s cultural heritage. It pays an important role to the foundation of Thai local economy for centuries.Thai products produced by local communities using indigenous skills and craftsmanship combined with available natural resources and raw materials. However, it is widely accepted that there exists a managerial gap in many small or micro-sized enterprise, many activities may not be enough to make those products are sustainable. Understanding the key issues affected Thai silk entire chain is an important step to improve the competitiveness of those products. In this paper, case studies are therefore conducted, as part of a research project to examine the current stage. The SCOR model is employed to identify challenges and pinpoint weaknesses in management practices also in what processes have an effect on inefficiency within the supply chain before radical suggestions improvements. This paper intends to report two case studies of Thai silk products and concludes with a summary of key issues that are raised in the fieldwork. Finally, conclusions and recommendations for further development of the main study are also provided in the paper.