Defence Technology Academic Journal

Detecting Objects in Aerial Photographs using Neural Network Techniques

Warakorn Luangluewut — 2023-11-20

This article discusses the study of aerial image analysis obtained from Unmanned Aerial Vehicles (UAVs) using the principles of artificial neural networks for image recognition. In this study, the author reviews the literature on image analysis for object detection and explores which models are suitable for the task of object detection in aerial images. The author selects the YOLO, Retinanet, and Fast R-CNN detection models after careful consideration. Through experimentation and study, the article reveals that when detecting objects in aerial images captured by UAVs, it is crucial to choose a detection model that aligns well with the equipment used for image capture. The experimental results show that utilizing the YOLO model yields a mean Average Precision (mAP) of up to 58.5% and a processing speed of 158.13 frames per second. These results highlight the superior accuracy and speed of object detection compared to other models tested with aerial images captured by unmanned aerial vehicles.

Research and Development of a Fire Fighting Rocket System

Paisarn Boonyarat — 2023-09-28

The Defense Technology Institute has researched and developed a Fire Fighting Rocket. Composite solid propellant was chosen for the propulsion system. The rocket is to be used as an alternative tool for delivering fire extinguishing agent type 90% ABC into the targeted fire in order to reduce the fire intensity, and support firefighting missions in buildings with heights less than 23 meters. This research has produced, tested, and evaluated the rocket until a prototype was obtained for the extinguishing agent explosive dispersion system and propulsion system, as well as static and dynamic testing to assess rocket functionality and fire-retarding or extinguishing performance. This research found that the propulsion system worked correctly and had sufficient thrust to propel a Fire Fighting Rocket with a diameter of 89 millimeters, a length of 130 centimeters, and a total weight not exceeding 7 kilograms to target at a height of 23 meters, and a distance from launcher of 100 meters, with accuracy measured by a probable error not exceeding 1.25% of the firing range. An electronic timer was used as a time delay system that can release 3 kilograms of fire 90% ABC extinguishing agent per shot covering an area of 13 - 30 square meters. The Fire Fighting Rocket can be fired into the target area by calculations from the firing control program and setting the time following the target coordinates. For fire-retardant performance, it was found that the rocket was able to retard fires that were burning in the Flashover phenomenon stage, which had a flame temperature of 500 - 1,000 degrees Celsius and were transitioning to fully developed stage, reducing the fire severity to the 200 - 300 degrees Celsius region. Tests were conducted with simulated fire stacks comparable to 3-A fire extinguisher test conditions and fires simulating fire within a living room or residence with area of 5 meters wide and 7 meters long. It was found that 8 rockets were required to reduce the fire intensity from the flashover phenomena down to levels that allow firefighters to enter and manage the fire using other methods.

Space Capability Development in Southeast Asian Countries : Prospect and Development Recommendation for Thailand

Kanok Bunnag — 2023-07-07

This article was intended for 3 primary purposes: (1) to study and analyze space capability development in Southeast Asian Countries; (2) to analyze prospects for future Thai space industry; and (3) to identify possible courses of action for the development of Thailand’s space capabilities. According to the documentary research, there were 6 Southeast Asian countries namely Indonesia, Thailand, Malaysia, Singapore, Vietnam, and Philippines with some degree of space capability. Additionally, there were 3 prominent trends in key efforts of the space capability development in the stated countries which are: (1) an effort to procure Geo Stationary Communication Satellites at the beginning stage; (2) a focus on establishing the domestic low earth orbit satellite development capability; and (3) an effort to establish a space agency to effectively manage space capabilities and drive forward space programs. However, as a launching state, the Southeast Asian countries were still deficient in acquiring such ability.

Thailand possessed a capability as a leading space nation in the region from its experience and cooperation networks. Considering Thailand’s current capability together with prospects from its ongoing attempt to foster space laws and space ecosystem, the regional focus on low earth orbit satellites, as well as the regional lack of own space launching capability, 4 key approaches were recommended for Thailand to utilize in the development of its space capability: (1) to conduct a comprehensive research on Thailand’s space ecosystem, benchmarking its capability with potential role model nations; (2) to focus on the development of low earth orbit launching capability which was lacking in the region; (3) to integrate national space capabilities with cooperation among public, private and academic sectors from the beginning of the policy development process; and (4) to cooperate with both space faring and space developing nations.

Design and Development of the VHF to S-Band Transverter

Aniwat Plodpai — 2023-07-07

This paper presents the design and construction of an S-band Up and Downconverters for LEO satellite and UAV applications. The Up & Down converters are constructed with subsystem modules. The modules are designed and built applying simulation techniques to optimize performance details using automotive grade components.
The 140 MHz IF standard is used. The PLL reference clock oscillator in the converters is either locked to a highly stable internal 10 MHz reference or external reference signal. If the proper signal level is present, the LO PLL will automatically lock to the external reference. The spectral purity, low phase noise and stability of the LO signals exceed the requirements of IESS-308/309.

Reduction of Body Odor on Digital Camouflage Fabric by Finishing with Beta-cyclodextrin

Kamut Kwankao — 2023-07-07

This research shows an attempt to produce digital camouflage fabric with body-odor reduction property via chemical finishing (coating) of fabric at various conditions and methods. Beta-cyclodextrin was used as odor absorber and acrylic acid was used as binder. Results indicated that the best method and condition for fabric finishing was to treat fabric with two dips-two nips process by dipping fabric in 20 g/L beta-cyclodextrin and 100 g/L acrylic acid, squeezing it between 2 rollers and dry it, and then repeating the dip-nip process again. The fabric was later cured at 130°C for 3 minutes. In this process, the fabric weight to chemical weight ratio was at 1:10 and the % wet pick up was at 70–80%. The finished fabric showed effective body-odor reduction property and this property remained intact after 50 washing cycles. Strength of finished fabric was comparable to that of unfinished fabric. Fabric stiffness and color depth increased after finishing, while its wettability decreased. However, after several wash cycles of finished fabric, these properties were improved and recovered.

The Analysis of Stress Strain from Voids in Solid Propellant

Surasith Palasarn — 2023-10-31

The strength of the HTPB base propellant was estimated by plotting the master curve, which obtained from the solid fuel uniaxial tensile test. The plotting master curve of stress strain and Young’s modulus can be used to evaluate the strength when the propellant are subjected to different loads. One of the problems encountered in the production of propellant is the formation of voids in the propellant, which affect load. In this work, the stress strain in the propellant was analyzed using the finite element method. The result of analysis in case of high temperature 60 C considers the maximum strain from voids. It was found that the strain was below the maximum value. That is, the effect of temperature and voids did not damage the propellant. In the case of the pressure inside the rocket motor, the strain of the propellant remains at an acceptable level. The
case of rocket acceleration, an acceleration of 70 g, the stress below the maximum value where the safety factor is 1.3 that is, in this case, the acceleration of the rocket rather affects the propellant. However, even though there is a problem with voids, propellant can still hold its shape without damage, which causing the rocket to malfunction.

Study of Alternative Fire Retardant Containers made from Kraft Paper for Fire Extinguisher

Suwicha Chankapoe — 2023-10-30

At present, government and private agencies provide support to officials and equipment for extinguishing forest fires. The greatest way to reduce the risk of heat and fire to people and property is to use a distant fire extinguishing technique. Current fire extinguisher technology allows for the deployment of fire retardants using rockets and unmanned aerial vehicles. The fire extinguisher has a fire retardant container and is made of polystyrene foam. The ecologically harmful styrene is produced during combustion, and the gradual disintegration of the leftover parts has an impact on the environment. An excellent environmentally friendly option is kraft paper. As a result, the action load for kraft paper containers was designed, modeled, and field tested using the same approach as fire extinguishers. As required, the fire retardant covers a surface area of at least 7 square meters. Knowledge of manufacturing process skills and qualification test results that can be utilized to design and build fire retardant containers made of kraft paper that can be used to replace the original containers and be mounted on unmanned aerial vehicles and rockets that are currently used for missions.

A Study of Archives Management of the Defence Technology Institute Archives

Waraporn Poolsatitiwat — 2023-09-03

This article aims to study 1) definitions of archives, 2) characteristics of archival records of the Defence Technology Institute Archives, and 3) the archives management processes of Defence Technology Institute Archives. The research scope is used concepts and theories on records and archives management to create the file plan and the retention schedule in compliance to the ISO 15489. This qualitative research is applied mixed methods: literature review, records surveys, observation, and semi-structured interview. The triangular analysis is used. The results reveal that 1) the archival records kept in the Defence Technology Institute Archives employ the definitions and contains 7 characteristics in accordance to the concepts and theories on records and archives management and the ISO 15489; 2) the archival records of the Defence Technology Institute Archives also have five attributes in terms of their provenance, their condition, their arrangement, their quantity, and their vital records collections; and 3) the archives management process of Defence Technology Institute Archives is consisted of records accessioning and records appraisal and it is required to include other four processes which are archival description and arrangement, archival preservation, archival services, and archival outreach. It is necessary for the traditional and digital archival records in the Defence Technology Institute Archives to be able to permanently preserve their characteristics if the Defence Technology Institute Archives successfully establishes the appropriate archives management procedures.

The Guidance for a System on Records Accessioning and Records Appraisal at the Defence Technology Institute Archives

Waraporn Poolsatitiwat — 2023-08-20

This article aims to study a process on records accessioning and records appraisal for traditional and digital records of the Defence Technology Institute Archives. The research scope is applied concepts and theories on archives management to manage records and archives in compliance to the ISO 15489. The research methods are qualitative applying literature review on concepts and theories of records accessioning and appraisal, including observation on archival recordkeeping practice. The research results are presented through analysis of records accessioning and appraisal concepts relevant to the Defence Technology Institute. This research is employed triangular analysis. The results show that currently the Defence Technology Institute Archives does not implement the process of records accessioning and records appraisal for non-current records to be preserved as archives. The research suggests that the Defence Technology Institute Archives should specify the guidance in terms of 1) the requirements for records appraisal for transferred records derived from other units under the Defence Technology Institute, 2) the accessioning process for the Defence Technology Institute Archives in accordance to archives management theory, 3) the acquisition policy, and 4) the procedure for records accessioning at the Defence Technology Institute Archives.