一個低花費並且高準確度的跌倒偵測系統，不僅能照護到年長者更能擴及各個年齡層來做使用。現今的跌到偵測系統除了高花費，其敏感度更會因為使用者的身體素質（如身高，年齡，體重等）影響偵測的準確度。此外，過去大部分跌倒偵測的研究，因為實際數據取得困難，而必須透過模擬跌倒動作收集數據來做為測試，無法完整考量到不同使用者實際情況。為了解決這些問題，我們提出了一個透過群聚外包收集數據，並視使用者情況調整來提升準去度的跌倒偵測系統，用現今流行並具有網路連線及偵測功能（三軸加速器等）的智慧型裝置作為工具。我們能夠透過群聚外包收集每個使用者的數據，依照使用者條件來進行分類並做跌倒偵測演算法的調整來提升準確度。本篇實驗結果顯示我們透過分類並作個類別調整，其跌倒偵測系統準確度從68%提昇至97%。

Being able to provide a low cost but highly accurate fall detection mechanism is decidedly beneficial not only to senior people but also to people of all ages. Most existing approaches are expensive and all subject to the shortfalls of being sensitive to user physique and personal factor. Additionally, most approaches are developed using limited, simulated fall data and often perform poorly in field tests. To resolve these issues, we propose, in this paper, an accurate, crowdsourcing-based, adaptive, fall detection approach using smart devices with built in wireless connection and sensors. We adaptively refine the fall detection algorithm and user grouping for improved accuracy based on the crowdsourced real data. The field tests show that the fall detection accuracy rate can be improved from 68% to 97% with our proposed approach.

Contents

1. Introduction…………………………………………….7
2. Related Work………………………………………….11
3. Our Propos Approach…………………………………14
3.1 Crowdsourcing Real User Data……………………14
3.2 System Adaptation for Better Accuracy…………...15
3.2.1 Categorize Users for Accuracy…………….15
3.2.2 Group-Specific Algorithms………………...16
3.2.3 A Reliable Accuracy Measure……………..18
3.3 Wearable Devices and Smart Phones……………...19
3.3.1 Device Initialization………………………..19
3.3.2 Fall-Detection Process……………………..20
4. Evaluation……………………………………………..22
4.1 Data collection……………………………………..22
4.2 Test Results………………………………………..22
5. Conclusion…………………………………………….24
BIBLIOGRAPHY………………………………………..25
List of Tables

Table 1: A list of test results to show that fall detection algorithms are user sensitive.……………………………...9


















List of Figures

Figure 1 The forward-fall and daily activity patterns for users of different age and physique. The number on the vertical axis represents the sum-of-acceleration value. Here (a) and (b) are forward-falls of two different persons, and (c) is for a daily activity of sitting down.……………………..…………………...8
Figure 2 An illustration of grouping tree.……………………..……………………16
Figure 3 The process of algorithm customization and adaptation……………………………………18
Figure 4 Differentiate genuine falls from false falls…………………………………………..21
Figure 5 Accuracy rate comparisons with and without system adaptation……………………………23

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