International Electrical Engineering Transactions

Software for Capital Investment Analysis: A Case Study on Walking Aid for Stroke Patients

2025-06-12T11:10:55+07:00

This research presents the development of a software for capital investment analysis, using a case study of a walking aid machine development for stroke patients. The software was created with Visual Basic for Applications (VBA) and Microsoft Access for database management and features a graphical user interface (GUI) for intuitive data input and result display. To support online use and collaboration, the system was also integrated with Microsoft SharePoint for cloud-based data storage and multi-device access. The software processes key financial inputs, including investment costs, annual income, operating expenses, and discount rates. It automatically computes major economic indicators such as NPV, IRR, DPB, and BCR. It also includes a sensitivity analysis function to assess project risk from changes in costs and revenues. Testing with actual project data showed an NPV of 33,822,276.50 THB, an IRR of 65.81%, a payback period of 2.19 years, and a BCR of 1.88, which confirms the project's economic feasibility. The developed software is suitable for use in health-related or technology-based projects requiring accurate and flexible financial analysis in both standalone and networked.

Design and Fabrication of 1x2 Multimode Interference Coupler Using Photosensitive Permanent Material for Wavelength Division Demultiplexing

2025-06-24T09:00:46+07:00

This report presents a 1x2 multimode interference coupler using photosensitive permanent material for wavelength division demultiplexing (WDM). The multimode interference (MMI) for multiplexer (MUX) and/or demultiplexer (DEMUX) architectures used different coupling lengths at long beat lengths for individual signal propagation. The MMI design was proposed with a short beat length and a single coupling length of two signals. The proposed MMI of a 1x2 coupler was simulated with the beam propagation method (BPM) using silicon dioxide (Si) and photosensitive permanent material “TMMR-S2000” as the cladding and core with the refractive indices of 1.45 and 1.57, respectively. The two light signals with 1310 nm and 1550 nm wavelengths were propagated through the 2.8 m wide input waveguide section, with the coupling length and width of 510 μm and 6.7 μm, respectively. The MMI was later fabricated using conventional photolithography with the help of hard baking. The simulation results showed that a high percentage of the two signals’ splitting power was realized. The performance characterization of the system was determined in terms of the insertion loss and extinction ratio. According to the numerical simulations, the extinction ratios for 1310 nm and 1550 nm lights are 19 dB and 17 dB, respectively, and the insertion losses for these wavelengths are 0.97 dB and 0.46 dB, respectively. When comparing the simulation results of the intensity distribution with the near-field patterns of the fabricated MMI at a coupling wavelength of 1310 nm, the desired splitting results were achieved. However, at 1550 nm, the findings were unfavourable.

Enhancing Watering System Efficiency of Organic Greenhouses Zonal Sensors and Solar Power Approaches in the Mekong Coastal Region

2025-06-11T19:45:51+07:00

The need for effective irrigation has grown as a result of the growing demand for sustainable agriculture, especially in organic greenhouses. Traditional irrigation techniques in the Mekong Coastal Region frequently result in energy inefficiency and water waste. In order to increase irrigation efficiency and meet the demand for precision watering, this study integrates solar-powered zonal sensor systems. The goal is to create a cutting-edge system that minimizes energy use and maximizes water use. Real-time data was gathered using capacitive moisture sensors and WeMos Arduino MEGA to operate solar-powered pumps that modify water distribution according to soil moisture levels. By eliminating the need for external energy sources, the system increased water efficiency and reduced consumption by 30% when compared to traditional methods, which helped to save money and promote sustainability. This study provides a scalable model for other areas dealing with comparable issues and shows how solar-powered, sensor-based irrigation systems can revolutionize organic farming in the Mekong Coastal Region.