EPI International Journal of Engineering

An Internet of Things-Based Trash Can Monitoring System

Felicia Kusuma — 2026-07-07

Everyday people throw trash in trash cans, both in private and public cans. Hence, trash cans become one of the objects needed by community. When a trash can is full or produces bad odor, it may disturb the surrounding community. When people want to throw trash but the can is full, they usually throw it everywhere. When trash produces bad odor, it can disturb sense of smell and may cause diseases to surrounding community. Naïve Bayes is one of the supervised data mining algorithms for classification. To predict a class, Naïve Bayes requires historical data to find the posterior of each class. The Internet of Things is a technology that involves a large number of processes and devices to improve the quality of life of people who use it and facilitate access to information and services provided. The trash can monitoring system is built using C and Python languages. C language is used to program the sensor device, while Python language is used to program the application. The database used in this system is MySQL. The system takes data from an MQ-4 gas sensor and an HC-SR04 ultrasonic sensor in the sensor device, which is installed in a trash can, to classify the condition of the trash can. Based on the results of accuracy performance evaluation, the accuracy with 60:40 data partition is 79%, 70:30 data partition is 78.9%, and 80:20 data partition is 79.1%.

The Analysis of Human Resource Management Performance during Work from Home Using Human Resource Scorecard Method

Saiful Mangngenre — 2026-07-07

The pandemic of COVID-19 spreading in Indonesia has forced the government to create an issue; work from home (WFH) policy. WFH changed the organization's work system which was originally face-to-face to become virtually. Changes in the work system are considered to be able to affect organizational performance. Indirectly, the implementation of WFH has an impact on the performance of the organization and its human resources. This study aims to analyze the performance of the management of PT. X especially in human resources during WFH implemented by the company. Results based on the strategic objectives obtained 7 KPIs. The results of the HR Scorecard method are that there are 4 perspectives, including financial perspective, customer perspective, internal business process perspective and learning and growth perspective. By using the Analytical Hierarchy Process (AHP) method, priority performance indicators were found, namely the percentage change in performance before and after training and employee satisfaction scores. Measurement of performance indicators against supervisory targets using the Traffic Light System (TLS) gives results if there are 2 assessment indicators that meet the target and 5 assessment indicators that have not reached the target. The indicator that experienced a decline was employee training. Using the 5 whys analysis method is known to cause a decrease in employee assessment indicator; the assessment that cannot be implemented virtually.

Inventory Control of Twin Tub Washing Machine Spare Parts Using Continuous Review (Q) and Periodic Review (P) Methods

Naila Anargya Fadhillah — 2026-07-16

In an electronics manufacturing industry, the production process of Twin Tub washing machines has not been operating optimally due to an imbalance between the quantity of purchased and required raw materials, namely spin motors, wash motors, v-belts, and water inlets. This condition makes it difficult for the company to determine the appropriate order quantity. This issue may negatively affect production continuity and increase total inventory costs due to shortages and overstocking of raw materials. Therefore, this study aims to control raw material inventory for twin tub washing machines in order to minimize total inventory costs. This study employs the Continuous Review (Q) Lost Sales and Periodic Review (P) Lost Sales methods. The results show that the Continuous Review (Q) Lost Sales method yields a total cost of IDR 2.735.326.321, which is lower than the Periodic Review (P) Lost Sales method with a total cost of IDR 2.751.408.021. Therefore, the Continuous Review (Q) Lost Sales method is selected as it provides the minimum total cost. Compared to the company’s current method, which amounts to IDR 2.796.945.916, this method results in cost savings of up to 2,20%. Thus, the projected total inventory cost for the upcoming period is IDR 2.299.642.132. The application of the Continuous Review (Q) Lost Sales method is proven to minimize total inventory costs while maintaining spare part availability to support sustainable production continuity.

Performance Optimization of Biomass Fly Ash as a Partial Cement Replacement in Concrete Based on Compressive Strength, Sorptivity, and Half-Cell Potential

Nur Okviyani — 2026-07-16

The use of biomass fly ash (BFA) as a supplementary cementitious material offers a practical approach to reducing cement consumption while enhancing concrete durability. This study evaluates the effect of BFA as a partial cement replacement on the mechanical and durability performance of concrete produced with river sand and freshwater. BFA was incorporated at replacement levels of 0%, 5%, 15%, and 25% by cement mass, with a constant water-to-binder ratio of 0.40. Compressive strength was tested at 7, 28, and 91 days, sorptivity was measured at 28 and 91 days, and the corrosion probability of embedded reinforcing steel was assessed using the Half-Cell Potential method from 7 to 91 days. The results show that BFA reduced early-age strength, especially at 15% and 25% replacement, due to the slower development of pozzolanic reactions. However, the later-age performance improved markedly. At 91 days, the mixture containing 25% BFA achieved the highest compressive strength of 36.46 MPa, representing a 27.48% increase over the control mixture. This mixture also produced the lowest sorptivity value of 0.91 mm, indicating reduced capillary water absorption. Half-Cell Potential results showed that all mixtures reached the low corrosion probability range at 91 days, with the 25% BFA mixture recording -59.13 mV. Overall, 25% BFA provided the best balance between compressive strength, water absorption resistance, and corrosion-related durability.

Keywords: biomass fly ash; compressive strength; concrete durability; half-cell potential; sorptivity