Journal of Engineering Science and Technology Management (JES-TM)

Round-Off and Truncation Error Trade-Off in Finite-Difference Numerical Differentiation: Optimal Step-Size Determination

2026-07-23T21:00:19+07:00

Numerical differentiation by finite differences is an inherently ill-conditioned operation in which two antagonistic error sources, truncation and round-off, govern the attainable accuracy. The objective of this study is to quantify this trade-off and to determine the step size that minimises the total error of the centred finite-difference operator. Using the smooth test function f(x) = -0.1x⁴ - 0.15x³ - 0.5x² - 0.25x + 1.2 evaluated at x₀ = 0.5, the first derivative was approximated for step sizes from 10⁰ to 10^-10 in IEEE-754 double precision, and the true, truncation, round-off, and total errors were measured and compared with a Taylor-series error model. The results reproduce the characteristic U-shaped error curve: truncation dominates for large h with second-order slope, round-off dominates for small h with slope minus one, and the minimum true error of 5.42x10^-12 occurs at h = 10^-6, in close agreement with the analytical optimum h_opt = (3ε|f|/M₃)^1/3. The centred scheme is shown to be markedly more accurate than the forward scheme. The study concludes that an a-priori optimal step size can be reliably predicted, providing practical guidance for derivative-based engineering computation.

Analysis Of The Causes Of Suboptimal Steering Gear Performance Based On Maintenance Factors And The Quality Of Spare Parts On MV. Mulianim

2026-09-07T23:20:57+07:00

The operational reliability of a ship's steering gear system is vital for navigation safety and vessel maneuverability, as regulated by International Maritime Standards (SOLAS). However, performance degradation often occurs due to inadequate maintenance practices and spare part constraints. This study aims to analyze the root causes of suboptimal steering gear performance on MV. Mulianim using a qualitative case study approach. Data were gathered through direct field observations, semi-structured interviews with chief and engine officers, and documentation audits (Engine Log Book and PMS records) over a 12-month period. Data validity was verified through source triangulation and analyzed using Miles and Huberman’s interactive model combined with Cause-and-Effect Analysis. The results revealed that steering gear hydraulic pressure dropped below the operational baseline (85–90 bar vs. standard 100 bar) due to high fluid turbidity, degraded viscosity, and internal bypasses. This condition was directly triggered by a 26.7% delay in Planned Maintenance System (PMS) tasks and severe spare part stockouts (25% critical spares unavailable). To prevent navigational hazards, strict adherence to PMS schedules and optimization of the spare part procurement pipeline are strongly recommended.

The Prediction of Hospital Readmission in Diabetic Patients Using Random Forest, XGBoost, and Support Vector Machine with an Explainable AI Approach

2026-08-27T13:23:30+07:00

Hospital readmission among patients with diabetes is an indicator of healthcare quality, treatment effectiveness, and hospitalization burden. Early prediction of readmission risk may support targeted interventions and reduce repeated hospital stays. This study developed prediction models using Random Forest, Extreme Gradient Boosting (XGBoost), and Support Vector Machine (SVM), with SHapley Additive exPlanations (SHAP) applied to interpret model predictions. The Diabetes 130-US Hospitals dataset comprised 101,766 medical records containing demographic characteristics, hospital visit history, laboratory results, diagnoses, and medication use. The outcome was defined as unplanned readmission within 30 days of discharge by recoding the original “<30,” “>30,” and “NO” categories. Data were divided into training and test sets at an 80:20 ratio using stratified sampling, preserving the class distribution of 11.16% readmitted and 88.84% not readmitted without resampling. Random Forest and XGBoost were trained on the full training set, whereas SVM used a stratified subsample of 10,000 training records because of computational constraints. All models were evaluated using the same test set. XGBoost achieved the best performance, with a balanced accuracy of 0.632 and ROC-AUC of 0.684. McNemar’s test indicated that its performance differed significantly from SVM but not from Random Forest. SHAP identified payer type, diagnosis categories, age group, prior inpatient history, and Clinical Risk Score as influential predictors. These findings demonstrate the feasibility of combining machine learning and explainable artificial intelligence for clinically interpretable readmission prediction. However, reliance on a single historical public dataset and the absence of external validation limit the model’s readiness for clinical deployment.

Performance Analysis of OTR Machine In The Black Tea Leaf Rolling Process At PTPN IV Bah Butong Unit

2026-09-17T14:37:24+07:00

This study aims to analyze the performance of the Open Top Roller (OTR) machine in the black tea leaf rolling process at PTPN IV Bah Butong Unit. The OTR machine is essential in black tea processing, functioning to grind and roll tea leaves after the withering process to shape and release cell sap. The recorded variables were material input, scheduled batch duration, downtime, operating time, and good output. The batches processed 3,020 kg of withered leaves; recorded duration ranged from 40 to 50 min per batch, with a mean of 44.4 min, while total downtime was 5 min and good output was 3,010 kg. Availability, Performance, and Quality were 98.87%, 91.12%, and 99.67%, respectively, producing an OEE of 89.79%. Performance was the lowest component because most batches exceeded the selected ideal cycle time of 40 min, although all remained within the plant’s operational range of 40–50 min. Average loading was 302 kg per batch, equivalent to 80.53% of the 375 kg nominal maximum. These results identify cycle-time consistency, rather than downtime or recorded mass yield, as the immediate improvement priority. The result must nevertheless be interpreted as a short observational snapshot: the Quality factor represents mass yield rather than sensory or biochemical tea quality, and the widely cited 85% OEE benchmark is a comparative convention rather than a universal acceptance limit. The findings describe only this ten-batch observation window.

Psychological Dynamics of Anxiety in Pregnant Women: A Positive Psychology Perspective

2026-07-22T17:54:40+07:00

Prenatal anxiety presents significant physical and psychological risks to both mothers and fetal development, yet conventional interventions often focus solely on symptom reduction rather than psychological empowerment. This study aims to explain the psychological dynamics of pregnant women experiencing anxiety from a positive psychology perspective. A Systematic Literature Review (SLR) approach was employed using the PRISMA framework, analyzing 20 selected peer-reviewed journals published between 2020 and 2025. The findings indicate that positive psychology interventions, specifically through the PERMA framework and the concept of “Flow,” are effective in mitigating prenatal anxiety, particularly during the third trimester. Positive emotions broaden cognitive awareness and facilitate a state of flow, serving as a cognitive coping mechanism to divert negative thoughts regarding childbirth. Deep engagement in activities such as prenatal yoga and self-hypnosis is proven to enhance maternal self-efficacy and a sense of accomplishment. Furthermore, supportive social relationships and the search for meaning assist mothers in redefining physical challenges and body image changes into empowering experiences. The integration of spiritual interventions and affirmation techniques also provides a significant relaxation effect, improving overall emotional preparedness and maternal-fetal attachment. In conclusion, these positive psychology strategies foster stable and holistic psychological well-being, empowering pregnant women throughout the gestational period

Evaluation of Drainage Systems Based on River Basins (Case Study: The Intersection of Jalan Jenderal Sudirman and Jalan D.I. Panjaitan)

2026-09-14T21:29:32+07:00

This study evaluates the drainage system at the intersection of D.I. Panjaitan Street and Jendral Sudirman Street in Bangkinang Kota District, Kampar Regency, Riau Province. The area frequently experiences waterlogging and flooding during periods of high rainfall intensity, which are suspected to be caused by sedimentation, channel blockages, and land-use changes that increase surface runoff. A quantitative descriptive method was employed through field surveys, drainage channel measurements, community interviews, and hydrological and hydraulic analyses. The data used consisted of 10 years of rainfall records from the Silam Rainfall Station and existing drainage channel data. Rainfall frequency analysis was carried out using the Normal, Gumbel, and Log Pearson Type III distributions, while the design discharge was calculated using the Rational Method. The capacity of the existing drainage channels was analyzed using Manning’s equation. The results indicate that the existing drainage system experiences several problems, including sediment accumulation, waste blockages, and structural deterioration in certain channel sections, which hinder water flow. The analysis shows that the total existing channel capacity is 66.68 m³/s, while the total design discharge is 47.77 m³/s, indicating that the drainage system is generally capable of conveying the runoff. However, one of the eight analyzed channels does not meet the required design discharge capacity and therefore requires improvement. This study provides recommendations for channel normalization, routine cleaning, and periodic maintenance to enhance drainage performance and reduce the risk of flooding in the study area.

Advancements in Metal Organic Frameworks for Energy Storage Applications: A Review of Current Research and Future Directions

2025-10-01T12:27:06+07:00

Growing energy demand and environmental pressures require storage materials that combine reversible capacity, efficient transport, and durability. Metal–organic frameworks (MOFs) offer tunable metal nodes, organic linkers, and pore structures, enabling their use as active frameworks, composite components, and precursors to derived materials. This review examines their application in lithium-ion, sodium-ion, lithium–sulfur, and zinc batteries, supercapacitors, and hydrogen storage, together with computational and artificial intelligence approaches to material design. Representative results include 2305 mAh g−1 after 500 cycles at 0.1 A g−1 for a MOF-derived lithium-storage electrode and 97.9% capacity retention after 1000 cycles at 1 A g−1 for a SnPS3@C sodium-storage electrode. These benchmarks arise from different chemistries and test conditions and do not establish a universal performance ranking. The review relates reported improvements to conductive networks, accessible reaction sites, and accommodation of structural change, while examining low conductivity, instability, and limitations in performance normalization. Hydrogen adsorption is assessed by distinguishing material uptake from complete-system storage requirements. Computational screening is considered alongside synthetic accessibility, model uncertainty, and experimental validation. Future research should prioritize application-specific hybrid architectures, matched-condition comparisons, scalable preparation, and device-level assessment to establish which MOF design principles remain effective beyond laboratory demonstrations

Design and Development of a Web-Based Financial Management Information System for a Wedding Organizer (Case Study: Novita Wedding Bangkinang)

2026-09-16T17:25:56+07:00

Novita Wedding Bangkinang is a wedding organizer business that provides various wedding services, including wedding packages and event management. Its financial management process, including recording customer data, income, expenses, and financial reports, is still conducted manually using notebooks. This condition causes several problems, such as recording errors, data duplication, difficulty in searching transaction information, and delays in preparing financial reports. This research aims to design and develop a web-based financial management information system for Novita Wedding Bangkinang. The system was developed using the FAST (Framework for the Application of System Thinking) method and implemented using Laravel 10 with MySQL as the database. The system provides features for managing customer data, wedding packages, income, expenses, division assignments, cash balances, and financial reports in an integrated system. System testing was conducted using functional testing, non-functional testing, and User Acceptance Testing (UAT). The test results show that the system functions according to the identified requirements and is accepted by the users. The developed system can support more structured, computerized, and efficient financial management processes at Novita Wedding Bangkinang.

Design and Construction of Portable Maggot Houses Using a Design Thinking Approach

2026-10-19T00:36:10+07:00

Organic waste dominates household waste streams in Indonesia, yet most households lack a practical, space-efficient way to process it. This study aimed to design and construct a portable maggot house for organic-waste management at household and small-business (UMKM) scale. A Research and Development design was applied using the five Design Thinking stages: empathize, define, ideate, prototype, and test. User needs were collected through interviews with ten households and UMKM in Bangkinang Kota and analyzed using descriptive qualitative analysis. Nine of the ten respondents discarded organic waste without processing; odour, flies, limited space, and lack of know-how were the main obstacles, and all ten preferred a portable device. The resulting prototype has a welded hollow-steel frame (39 × 55 cm footprint, 75 cm frame height, 15 cm legs), stacked biopond trays with an inclined side and perforated pipe for self-harvesting of prepupae, an egg-laying chamber, and a sloped roof. In a preliminary test on moist rice bran and household organic waste, the prototype supported the development of Black Soldier Fly (BSF) larvae over a cycle of about 16 days, without a strong putrid odour. The design offers a practical basis for decentralized organic-waste processing; quantitative performance testing remains for future work.

Website-Based Medicinal Plant Information System Design for Universitas Pahlawan Botanical Garden Using the Prototype Method

2026-08-13T13:31:35+07:00

The Medicinal Plant Collection Garden of Universitas Pahlawan (UP) Botanical Garden manages approximately 60 species of medicinal plants as a means of conservation and education, yet its publication remains limited to physical banners and social media. The QR codes installed on-site also still direct visitors to the general Wikipedia platform, resulting in information that is less specific and whose scientific validity is difficult to verify. This study aims to design and build a Medicinal Plant Information System website as an independent and accurate information medium. The system was developed using the Prototype method to facilitate continuous interaction and feedback with users. The application was built using the Laravel 10 framework and a MySQL database, with three user roles: Visitor, Admin, and Person in Charge. Key features include a medicinal plant catalog, an activity photo gallery, news articles, public reviews, and a PDF report export module. Testing was conducted through Black Box Testing and User Acceptance Testing (UAT). The test results show that all feature functionalities ran successfully with a high level of user acceptance, indicating that this medicinal plant information system is feasible for implementation to optimize digital botanical literacy at the UP Botanical Garden.

Evaluation of The Drainage System at The University of Pahlawan Tuanku Tambusai Based on An Analysis of The Rainfall Catchment Area

2026-09-14T21:33:22+07:00

Infrastructure development at the Universitas Pahlawan campus has led to land-use changes that potentially increase surface runoff and affect the performance of the drainage network. This study aims to analyze catchment area characteristics, calculate design runoff discharge, and evaluate the capacity of the existing drainage network by comparing design runoff discharge with channel capacity. A quantitative descriptive method was employed, utilizing hydrological and hydraulic analysis approaches. Data sources included 10 years of rainfall data from the Silam Station, topographic data and field observations, Rainfall analysis was conducted using probability distributions; runoff discharge was calculated using the Rational Method, and channel capacity was analyzed using Manning's Equation. The results indicate that the Universitas Pahlawan campus area is divided into four catchment zones (A1, A2, A3, and A4) with a total area of 4,27 hectares. Frequency analysis identified the Log Pearson III distribution as the best fit, yielding a design rainfall of 150.31 mm for a 10 year return period. Of the 12 channels evaluated, all channels were individually capable of accommodating the design runoff discharge; however, overtopping was identified in Channel 10, as this channel is located at the confluence of four flows from Zones A1 to A4 that converge at the same outlet point, causing the discharge from the four upstream channels to concentrate simultaneously and exceed the channel's holding capacity. This study provides information on the performance of the campus drainage system and serves as a basis for considering capacity improvements and regular channel maintenance.