Effective Pattern Recognition of Control Charts Using a Dynamically Trained Learning Vector Quantization Network

應用動態訓練提昇LVQ網路即時辨識管制圖異常形狀之績效

顧瑞祥(Ruey-Shiang Guh) ； 薛友仁(Yeou-Ren Shiue)

《工業工程學刊》 25卷1期 (2008/01) Pp. 73-89

https://doi.org/10.29977/JCIIE.200801.0008

摘要

特定的管制圖異常形狀通常與特定的製程異常原因有關，因此，即時有效地偵測及分辨管制圖中出現的異常形狀，可幫助品管人員快速找到造成製程異常的原因，從而降低不良品發生的機率。近年來，有很多研究利用類神經網路線上即時辨識管制圖的異常形狀，然而，如何在即時辨識的條件下，精確地分辨異常形狀的形狀類別，是這一類研究常有的共同問題。這個問題來自於此領域絕大部份的研究皆採用靜態(static)監督式類神經網路作為辨識管制圖的工具，如倒傳遞網路(back propagation network, BPN)或學習向量量化(learning vector quantization, LVQ)網路，但在即時辨識的環境中，管制圖的形狀事實上是一種動態(dynamic)的時間序列(time series)，因此，問題的根本原因在於靜態類神經網路無法有效地辨識動態的管制圖形狀，然而訓練動態類神經網路（如Niocognitron）執行辨識任務是相當複雜且困難的。有鑑於此，本研究提出一個動態訓練法則，以提昇LVQ網路即時辨識管制圖異常形狀之績效。模擬結果顯示經過動態訓練之LVQ網路，在辨識管制圖異常形狀的精度與速度上，均優於此領域文獻中所提出的類神經網路辨識模式。雖然本研究是以提昇LVQ網路之辨識績效為主要的研究目的，本文所提出的動態訓練法則也可以應用在其他的類神經網路架構上，如自適應共振理論(adaptive resonance theory, ART)網路。

關鍵字

靜態類神經網路 ； 形狀辨識 ； 管制圖 ； 統計製程管制 ； 學習向量量化網路

並列摘要

Unnatural control chart patterns (CCPs) are associated with a particular set of assignable causes for process variation. Hence, effectively recognizing CCPs can substantially narrow down the set of possible causes to be examined, and accelerate the diagnostic search. Recently, machine-learning techniques, especially the artificial neural network (ANN), have been widely used as an effective tool for CCP recognition (CCPR) tasks. Most ANN applications in CCPR have been using static supervised ANNs, such as back propagation networks (BPNs) and learning vector quantization (LVQ) networks. The false recognition problem (i.e. the patterns are misclassified) commonly encountered for these ANN-based CCPR models is mainly due to the fact that the static ANNs cannot appropriately deal with dynamic patterns, such as CCPs. In this research, a dynamic training algorithm is designed to provide an LVQ network-based CCPR model the capability to on-line recognize the dynamic CCPs that vary over time. The numerical results using simulation show that the dynamically trained LVQ network-based model proposed in this research performs much better than other ANN-based models reported in literature with respective to recognition accuracy and speed. Although this research considers the specific application of a real-time CCPR model based on an LVQ network, the proposed dynamic training algorithm could be applied to CCPR systems based on other ANN architectures in general.

並列關鍵字

static artificial neural network ； pattern recognition ； control chart ； statistical process control ； learning vector quantization

參考文獻

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