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| Title: | 集成式學習應用於電子零組件供應鏈需求預測
Ensemble learning for demand forecasting in electronics supply chains |
| Authors: | 郭泰竹
Kuo, Tai-Chu |
| Contributors: | 莊皓鈞
周彥君
Chuang, Hao-Chun
Chou, Yen-Chun
郭泰竹
Kuo, Tai-Chu |
| Keywords: | 電子供應鏈
需求預測
集成式學習
Electronics supply chains
Demand forecasting
Ensemble learning |
| Date: | 2019 |
| Issue Date: | 2019-08-07 16:09:08 (UTC+8) |
| Abstract: | 隨著半導體產業以及電子成品業快速發展，電子零組件之供應成為該產業中重要的一環。而通路商在整條供應鏈當中所扮演的角色尤其重要，需要及時反映下游需求並知會上游，達成良好的需求供給，也需要控制存貨水位，降低存貨成本。根據文獻探討，半導體通路商遇到以下三個困難，包括需求前置時間過長，需求變動量大，以及零組件生命週期短。本研究之研究問題為「如何在需求不穩、資料有限的狀況下，預測前置時間需求？」，希望能透過機器學習之技術，預測未來時間之前置需求量，協助通路商控制良好的存貨水位，提高其營業獲利。
本次研究與亞洲一代表性零組件通路商合作，其在擁有龐大營業額下，也需面對相當高的存貨成本，無論是訂貨超出或是不足，都需負擔存貨與缺貨成本。本研究運用其近三年之資料，結合下游製造廠商對於未來需求之預期數量矩陣，針對通路商零組件資料建立預測情境。目標是更精準預測在未來前置時間，下游廠商對於半導體通路商的零組件需求。
為達成以上目標，本研究使用機器學習演算法以及集成式模型架構，首先就不穩定的需求資料進行Temporal Aggregation，並利用跨產品的訓練樣本，以及不同演算法(包含XGBoost、LightGBM、Random Forest等)，配合多種參數隨機組合，訓練多個需求預測模型。接著，利用集成式作法(ensemble)將模型混合，本研究使用的方法為平均法以及爬山法(hill-climbing)結合向前選取法(forward-selection)，降低各個單一模型預測所產生的偏誤，經較小樣本的完整資料預測測試，和較大樣本的多缺失資料預測測試，本研究發現，利用所提出的資料建構和集成預測，能較各種單一模型顯著降低需求預測誤差，並較該通路商的既有預測方法，能優化70%-80%的零組件預測，使其更能優化存貨控制。
As the semi-conductor and electronics industries grow, the supply of components has become an important part of this industrial chain. Particularly, the distributor is the key of the supply chain because it is responsible for holding inventories to meet demand from downstream plants, in addition to sourcing from upstream vendors with long production lead time. According to the related literature, the distributor faces the problems including the long lead time, high demand volatility, and short life time cycle of the components. This study addresses the following question - How to predict demand over long lead time with limited data and unstable demand series?
This study collaborates with a representative electronics distributor in Asia. Despite its large revenue, the distributor operates under high inventory costs due to excessive holdings or shortages. This study first collects data on downstream demand and rolling forecast over three years. After data engineering, we build scenarios from data sets. The objective is to improve accuracy of demand forecasting, such that the distributor can better prepare for volatile demand from downstream production plants.
To achieve the goal, this study takes machine learning and ensemble learning techniques. First, we use temporal aggregation to smooth demand series and reduce noise. We construct cross-item training samples for different algorithms. After training models with random hyper-parameter search, we use model-averaging and hill-climbing methods to ensemble models` predictions. After testing a relatively small samples with complete data and a larger sample with incomplete data, we show that the proposed approaches can reduce prediction errors, compared with single models. Our method also outperforms the distributor`s internal forecast method for 70%-80% of components, such that the company can apply our method for better inventory control. |
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| Description: | 碩士
國立政治大學
資訊管理學系
107356002 |
| Source URI: | http://thesis.lib.nccu.edu.tw/record/#G0107356002 |
| Data Type: | thesis |
| DOI: | 10.6814/NCCU201900450 |
| Appears in Collections: | [資訊管理學系] 學位論文
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