Yooyen, Soemsak

Preferred name

Yooyen, Soemsak

Alternative Name

Yooyen, S.

Main Affiliation

International Academy of Aviation Industry

soemsak.yo@kmitl.ac.th

Now showing 1 - 8 of 8

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The Development of a Prototype for Low Altitude Operations of Unmanned Aircraft Flight Plan Systems
(2025-09-01)
Yenpiem, Siriporn
;
Yooyen, Soemsak
;
Tungkasthan, Anucha
;
Banchongaksorn, Sasicha
;
Yoneyama, Keito R.
The use of Unmanned Aircraft has grown significantly in Thailand and worldwide, particularly for operations below 450 feet. However, unlike manned aviation, there remains a lack of integrated digital platforms to manage flight plans that align with regulatory and operational requirements specific to low altitude activity. This study employed both secondary research and expert interviews to gather technical and regulatory user requirements. The data were analyzed and validated using Structural Equation Modeling to identify key variables influencing safety operations. Based on these findings, a standardized low altitude flight plan format was developed and converted into a prototype web platform called GoFly. The system enables operators to register aircraft and pilot credentials and to submit flight plans digitally. This platform addresses the current fragmentation in Thailand’s flight planning process by centralizing operations and enhancing regulatory compliance. The study contributes to the foundational development of a digital Unmanned Aircraft Traffic Management system tailored for emerging airspace users in Thailand and demonstrates potential scalability to other international regulatory contexts.
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CHT/CFD analysis of thermal sensitivity of a transonic film-cooled guide vane
(2019-01-01)
Prapamonthon, Prasert
;
Yooyen, Soemsak
;
Sleesongsom, Suwin
Thermal parameters are important variables that have great influence on life time of turbine vanes. Therefore, accurate prediction of the thermal parameters is essential. In this study, a numerical approach for conjugate heat transfer (CHT) and computational fluid dynamics (CFD) is used to investigate thermal sensitivity of a transonic guide vane which is fully film-cooled by 199 film holes. Thermal barrier coating (TBC), i.e., the typical TBC and a new one as the candidate TBC, and turbulence intensity (Tu), i.e., Tu=3.3%, 10% and 20%, are two variables used for the present study. At first the external surface temperatures of the vane material are compared. Next, the TBC surface temperatures are considered. Results show the major role of the lower thermal conductivity of TBC which results in the lower and more uniform temperature on the external surface of the vane substrate. Finally, the thermal sensitivity is presented in terms of the percentage reduction of the external surface temperatures of the vane material and the structural temperatures of the vane material at midspan, including the variations of average and maximum vane temperatures. Results show that TBC and Tu have significant effects on the external surface and structural temperatures of the vane substrate. The lower thermal conductivity of TBC leads to the higher difference between the thermal conductivity of the vane substrate and TBC, the reduction of heat transfer and the more uniform temperature within the vane structure. The results also show more effective protection for the average vane temperature from the two TBCs at higher Tus. However, Tu does not significantly affect the reduction of the maximum vane temperature even though the new TBC, which has the very low thermal conductivity, is used.
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Structural Equation Modeling for Airspace Optimization: The Analysis of Causal Factors Influencing Aviation Safety
(2026-05-01)
Yenpiem, Siriporn
;
Yooyen, Soemsak
;
Delahaye, Daniel
;
Yoneyama, Keito R.
Increased flight volumes necessitate urgent reforms in Airspace Management (ASM) to mitigate risks of fatalities and near-misses. In order to enhance aviation system safety, the International Civil Aviation Organization (ICAO) mandates that state parties must conduct the Universal Safety Oversight Audit Program (USOAP) to continuously monitor civil aviation. This research aims to identify critical factors influencing Thailand’s ASM by employing experimental design and Structural Equation Modeling (SEM) to analyze influences and relationships among communication, surveillance, navigation, Air Traffic Management (ATM), and ASM. The methodology includes stimulation and a questionnaire-based survey conducted with aviation professionals and mapping out their answers to find the influences, relationships, and importance of the different factors. The results were validated using various statistical tools. The findings indicate signi1ficant direct and indirect effects on ASM, emphasizing that effective communication and robust surveillance are essential for safety and operational efficiency. This study highlights the need to increase the ASM framework, providing actionable insights for optimizing air traffic control in response to the growing air traffic demand. Furthermore, SEM for Airspace optimization can be applied internationally to significantly reduce accidents and incidents in the future.
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Investigation of cooling performances of a non-film-cooled turbine vane coated with a thermal barrier coating using conjugate heat transfer
(2018-04-01)
Prapamonthon, Prasert
;
Yooyen, Soemsak
;
Sleesongsom, Suwin
;
Dipasquale, Daniele
;
Xu, Huazhao
The aim of this paper is to numerically investigate cooling performances of a non-film-cooled turbine vane coated with a thermal barrier coating (TBC) at two turbulence intensities (Tu = 8.3% and 16.6%). Computational fluid dynamics (CFD) with conjugate heat transfer (CHT) analysis is used to predict the surface heat transfer coefficient, overall and TBC effectiveness, as well as internal and average temperatures under a condition of a NASA report provided by Hylton et al. [NASA CR-168015]. The following interesting phenomena are observed: (1) At each Tu, the TBC slightly dampens the heat transfer coefficient in general, and results in the quantitative increment of overall cooling effectiveness about 16-20%, but about 8% at the trailing edge (TE). (2) The protective ability of the TBC increases with Tu in many regions, that is, the leading edge (LE) and its neighborhoods on the suction side (SS), as well as the region from the LE to the front of the TE on the pressure side (PS), because the TBC causes the lower enhancement of the heat transfer coefficient in general at the higher Tu. (3) Considering the internal and average temperatures of the vane coated with two different TBCs, although the vane with the lower thermal conductivity protects more effectively, its role in the TE region reduces more significantly. (4) For both TBCs, the increment of Tu has a relatively small effect on the reduction of the average temperature of the vane.
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Ozonation effectiveness on the mitigation of airborne microorganisms and particulate matter for enhanced indoor air quality
(2026-01-01)
Yooyen, Soemsak
;
Pohsa, Akrom
;
Hayeema, Asmin
;
Fuengfung, Jakkarin
;
Sookpordee, Pilun
The efficacy of gaseous ozonation in eliminating indoor air pollutants has been investigated to improve indoor air quality. The ozone generator was operated until the air conditioning room attained ozone concentrations of 25, 50 and 75 ppm for 15 minutes. Rooms exposed to all ozone concentrations were efficacious in eradicating microorganisms and particulate matter (PM) within the air-conditioned room, with the level of elimination contingent upon the ozone concentration and duration of the test. Among these investigations, the 75 ppm ozone condition was the most efficacious in diminishing room microbe numbers. Ozone gas activity exerted a more pronounced effect on diminishing the number of PM. PMs within the 1.0–5.0 µm range were 75%–90% eliminated following the attainment of ozone levels of 75 ppm. This inquiry suggests that pre-treatment of the air with ozone can improve the indoor air quality and make it safer for occupants.
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Vision-based spacecraft pose estimation via a deep convolutional neural network for noncooperative docking operations
(2020-09-01)
Phisannupawong, Thaweerath
;
Kamsing, Patcharin
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Torteeka, Peerapong
;
Channumsin, Sittiporn
;
Sawangwit, Utane
The capture of a target spacecraft by a chaser is an on-orbit docking operation that requires an accurate, reliable, and robust object recognition algorithm. Vision-based guided spacecraft relative motion during close-proximity maneuvers has been consecutively applied using dynamic modeling as a spacecraft on-orbit service system. This research constructs a vision-based pose estimation model that performs image processing via a deep convolutional neural network. The pose estimation model was constructed by repurposing a modified pretrained GoogLeNet model with the available Unreal Engine 4 rendered dataset of the Soyuz spacecraft. In the implementation, the convolutional neural network learns from the data samples to create correlations between the images and the spacecraft’s six degrees-of-freedom parameters. The experiment has compared an exponential-based loss function and a weighted Euclidean-based loss function. Using the weighted Euclidean-based loss function, the implemented pose estimation model achieved moderately high performance with a position accuracy of 92.53 percent and an error of 1.2 m. The in-attitude prediction accuracy can reach 87.93 percent, and the errors in the three Euler angles do not exceed 7.6 degrees. This research can contribute to spacecraft detection and tracking problems. Although the finished vision-based model is specific to the environment of synthetic dataset, the model could be trained further to address actual docking operations in the future.
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A Stress Tensor-based Failure Criterion for Ordinary State-based Peridynamic Models
(2022-01-01)
Dipasquale, Daniele
;
Sarego, Giulia
;
Prapamonthon, Prasert
;
Yooyen, Soemsak
;
Shojaei, Arman
Peridynamics is a recent nonlocal theory of continuum mechanics that is suitable to describe fracture problems in solid mechanics. In this paper, a new failure criterion based on the stress field is developed by adopting the damage correspondence model in the ordinary state-based peridynamic theory. The proposed stress tensor-based failure criterion is capable of predicting more accurately crack propagation in the mixed mode I-II fracture problems different from other failure criteria in peridynamics. The effectiveness of the proposed model is demonstrated by performing several examples of mixed-mode dynamic fracture in brittle materials.
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An enhanced learning algorithm with a particle filter-based gradient descent optimizer method
(2020-08-01)
Kamsing, Patcharin
;
Torteeka, Peerapong
;
Yooyen, Soemsak
This experiment integrates a particle filter concept with a gradient descent optimizer to reduce loss during iteration and obtains a particle filter-based gradient descent (PF-GD) optimizer that can determine the global minimum with excellent performance. Four functions are applied to test optimizer deployment to verify the PF-GD method. Additionally, the Modified National Institute of Standards and Technology (MNIST) database is used to test the PF-GD method by implementing a logistic regression learning algorithm. The experimental results obtained with the four functions illustrate that the PF-GD method performs much better than the conventional gradient descent optimizer, although it has some parameters that must be set before modeling. The results of implementing the MNIST dataset demonstrate that the cross-entropy of the PF-GD method exhibits a smaller decrease than that of the conventional gradient descent optimizer, resulting in higher accuracy of the PF-GD method. The PF-GD method provides the best accuracy for the training model, 97.00%, and the accuracy of evaluating the model with the test dataset is 90.37%, which is higher than the accuracy of 90.08% obtained with the conventional gradient descent optimizer.

Yooyen, Soemsak

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