International Journal of Economic, Business, Accounting, Agriculture Management and Sharia Administration (IJEBAS)
Vol. 6 No. 3 (2026): June

DEMAND PATTERN-SPECIFIC FORECASTING FOR SPARE-PART INVENTORY: ENSEMBLE MODEL EVIDENCE FROM INDONESIAN HEAVY EQUIPMENT DISTRIBUTION

Like Ati Handayani (Institut Teknologi Bandung)
Dermawan Wibisono (Institut Teknologi Bandung)



Article Info

Publish Date
26 May 2026

Abstract

PT Cakra Harmoni Sentosa (HCS), the largest heavy equipment distributor in Indonesia, faces a supply chain performance problem at its highest-revenue plant, Plant Sungai Danau (SDU). With IDR 1.1 trillion in annual spare-part transactions, SDU records a customer service level of 75%, which is five percentage points below the 80% target, while Days of Inventory reaches 87 days against the 75-day benchmark. Both shortfalls originate from reliance on a 12-month Moving Average forecasting method applied uniformly across a portfolio where 90% of SKUs show intermittent or lumpy demand patterns. This paper evaluates 23 forecasting model variants per demand pattern through walk-forward validation. Methods tested range from classical statistical approaches including Croston, SBA, and TSB to machine learning models such as XGBoost and LightGBM, deep learning architectures including LSTM and N-Beats, and ensemble combinations. Performance is assessed using RMSE and MAE on non-zero periods alongside the Stock-Keeping-Oriented Prediction Error Cost metric with stockout-weighted parameters. Findings show that a demand-pattern-specific Ensemble of SES, SBA, LSTM, and N-Beats achieves the strongest performance for lumpy and intermittent SKUs, cutting RMSE by 43.9% and SPEC by 36.3% on lumpy items relative to the MA12 baseline.

Copyrights © 2026






Journal Info

Abbrev

IJEBAS

Publisher

Subject

Economics, Econometrics & Finance

Description

This journal aims to examine new breakthroughs and current issues regarding advances in science and technology in the fields of Economics, Business, Sharia Administration, Accounting and Agriculture ...