Indradi Wijatmiko

Purpose: This research develops and validates a comprehensive technology-based assessment system for heritage building restoration that integrates project management triangle factors with adaptive reuse sustainability factors, addressing the critical gap in standardized evaluation frameworks for developing countries. Design/methodology/approach: The research design used structural equation modelling-partial least squares, data were collected from 100 construction professionals across seven heritage buildings in Java Island, Indonesia. The model integrates capital investment, asset condition and regulatory factors with scope, time and cost management dimensions through advanced psychometric validation. Findings: The data collected from 100 construction professional in Indonesia, and the results reveal capital investment as the dominant factor influencing project management outcomes (β = 0.481–0.567), while regulatory factors show moderate relationships particularly with scope management (β = 0.328). Asset condition exhibits weaker associations, reflecting funding prioritization over technical considerations in developing country contexts. The system explains 29.8–44.5% variance in project management constructs with strong psychometric properties (Construct Realibility (CR) > 0.7, average variance extracted >0.5) and acceptable fit (SRMR = 0.076, Normed Fit Index (NFI) = 0.912). Originality/value: This research provides the first empirically validated integrated assessment technology combining adaptive reuse sustainability factors with project management principles in heritage restoration contexts, offering practitioners systematic tools for feasibility assessment and resource optimization through rigorous quantitative validation in Southeast Asian developing country settings.

This study examines the relationship between land cover change and the extent of inundation and the value of economic losses due to flooding in Lumajang district in 1995, 2014, and 2023. Using a spatial approach based on satellite imagery and hydraulic simulation, as well as the ECLAC method in calculating losses, this study shows that the loss of natural land cover, such as forests and wetlands, as well as the expansion of residential areas, contributed significantly to the increase in inundation intensity and economic losses. These findings are important for spatial planning that is adaptive to hydrometeorological disaster risks. In addition, this research also supports the implementation of mitigation policies based on spatial and hydrological data that are appropriate to the conditions of the Jatiroto watershed.

Floods are one of the most frequent natural disasters and cause considerable economic, infrastructure, and social losses, especially in areas experiencing land use/land cover change (LULC). In this study, we use GeoHECRAS and GIS to model the flood risk due to historic land use changes in the Jatiroto watershed (DAS Jatiroto) in Lumajang (East Java, Indonesia). The study evaluates the consequences of land-cover conversion between 1995 and 2023 on flood processes, including the variations of flood extent, depth, and duration. Rainfall, land use, soil types, and topography data were used to construct the flood prediction model, and the model was validated with historical flooding events. The findings indicate that the flood area is found to have increased substantially from 12.22% in 1995 to 15.66% in 2023. Moreover, flood depth was also raised, particularly in areas with urban and agricultural expansion. The research emphasizes that land-use changes play a significant role in raising the flood risk and that GeoHECRAS can simulate the flood incidences. These results can be useful for the optimization of flood disaster management and prevention in the rapidly urbanizing areas. More robust flood risk management strategies could be developed if the effects of climate change were taken into account in future studies on flood risk modeling simulations.

Purpose: This research intends to examine inclined pile structures to analyze the effectiveness of inclined pile structures by analyzing the relationship between the transmission coefficient and wave steepness based on several parameters including pile slope (α), the distance between the piles in one row (D), distance between the top of the piles (b), depth (d), wave height (H) and wave period (T). Theoretical reference: Wave breaking structures are widely used to protect beaches from the impact of sea waves that propagate to coastal areas. Wave breakers are coastal structures that are used to withstand and break the height of waves coming towards the beach, so that the area behind the breakwater does not receive much influence from the waves. When passing through coastal buildings, the waves will be reflected (reflection) and forwarded (transmission). Method: Physical laboratory simulations have been carried out to obtain wave data interacting with the inclined pile structure. Next, energy spectrum analysis was carried out to determine the energy spectrum of incident, reflection and transmission waves from wave probe measurements in the form of time series data. Each energy spectrum is used to see the reflection and transmission capabilities of the pile structure from the reflection and transmission coefficients. Result and Conclusion: From this research it is known that in general Kt has an inverse relationship to wave steepness value (Hi/gT2 and Hi⁄ L). The most effective water level for this breakwater is the average water level. The most effective spacing scenario is α=600 scenario; D=1.69cm; b= 5 cm with a Kt value of 0.652 at Hi/gT2 of 0.006, Kr= 0.103 and Kd= 0.245, so only 65.2% of the waves can pass through the structure, 10.3% is reflected, and 24.5% is removed. Implication of research: These lost waves can be caused by waves traveling through the inclined pile structure, due to collisions between waves or other things. Originality/ value: One of the wave breaker innovations that are being developed is the pile structure. Currently, a lot of research has been carried out regarding upright pile structures.

Purpose: This research intends to build a performance index model of main stucture by case study in IPDMIP.   Theoretical reference: It is important to evaluate the percentage weights of 6 (six) variables in the Irrigation System Performance Index (ISPI) assessment so that irrigation managers get assessment results close to actual conditions in the field, improving the quality of irrigation system management.   Method: The methodology or the main structure model in this study was analyzed by using SEM-PLS software and GRG analysis. The selection of a research location in the Central Authority Irrigation Area was by considering the same data availability as previous research. In this research, the author used the Smart-PLS (Partial Least Square) application to analyze and reduce variables, which were then analyzed again using the GRG (Generalized Reduced Gradient) method to calculate non-linear equations.   Result and Conclusion: The result shows that in this equation, there is only 1 (one) variable, 3 (three) dimensions, and 13 (thirteen) indicators analyzed. After analyzing with SEM PLS, followed by GRG (Generalized Reduced Gradient) analysis with the solver in Microsoft Excel, changes in variable weights occur, so the new model equation for the main structure performance index (Y) is 0.348, with structure body dimensions of + 0.492 and door & gear to operate of +0.160. Mud Bags and drain doors apply to the Central Authority.   Implication of research: Based on the results of previous research, where the assessment weight of the variable of the main irrigation network (with a weight of 0.744) is greater than the tertiary irrigation network (with a weight of 0.256). Originality/ value: the role of the main irrigation network is more dominant in channeling water from the intake to the tertiary irrigation network. However, previous research has not been completed since the main structure still has a level below it and has not been included in the scope of previous research.