## Line Chart: Accuracy vs. Attack Ratio for Federated Learning Methods
### Overview
The image is a line chart comparing the performance (accuracy) of seven different federated learning methods or algorithms as the "Attack ratio" increases. The chart demonstrates how each method's accuracy degrades under increasing adversarial conditions. The overall trend for all methods is a decline in accuracy as the attack ratio rises, but the rate of decline varies significantly.
### Components/Axes
* **Chart Type:** Multi-line chart with markers.
* **X-Axis:** Labeled **"Attack ratio (%)"**. The scale runs from 0 to 50 in increments of 10 (0, 10, 20, 30, 40, 50).
* **Y-Axis:** Labeled **"Accuracy (%)"**. The scale runs from 65 to 95 in increments of 5 (65, 70, 75, 80, 85, 90, 95).
* **Legend:** Located in the **bottom-left corner** of the chart area. It lists seven data series with corresponding colors and markers:
1. **FedAvg** - Blue line with square markers (□).
2. **ShieldFL** - Orange line with diamond markers (◇).
3. **PBFL** - Green line with upward-pointing triangle markers (△).
4. **Median** - Purple line with circle markers (○).
5. **Biscotti** - Gray line with star/asterisk markers (☆).
6. **FoolsGold** - Brown line with downward-pointing triangle markers (▽).
7. **Ours** - Red line with circle markers (○).
* **Grid:** A light gray grid is present in the background.
### Detailed Analysis
The following describes the visual trend for each data series and approximates the data points by reading the chart. Values are approximate due to visual estimation.
1. **Ours (Red line, circle markers):**
* **Trend:** The most resilient line. It shows a very gradual, almost flat decline until an attack ratio of 30%, after which it slopes gently downward.
* **Approximate Data Points:** (0%, ~95%), (10%, ~95%), (20%, ~95%), (30%, ~94%), (40%, ~92%), (50%, ~90%).
2. **Median (Purple line, circle markers):**
* **Trend:** A steady, moderate downward slope across the entire range.
* **Approximate Data Points:** (0%, ~95%), (10%, ~94%), (20%, ~93%), (30%, ~90%), (40%, ~87%), (50%, ~85%).
3. **FedAvg (Blue line, square markers):**
* **Trend:** A consistent downward slope, slightly steeper than Median after 20%.
* **Approximate Data Points:** (0%, ~95%), (10%, ~93%), (20%, ~92%), (30%, ~89%), (40%, ~85%), (50%, ~82%).
4. **ShieldFL (Orange line, diamond markers):**
* **Trend:** Follows a path very close to FedAvg, with a nearly identical slope, ending slightly lower.
* **Approximate Data Points:** (0%, ~95%), (10%, ~93%), (20%, ~91%), (30%, ~88%), (40%, ~84%), (50%, ~81%).
5. **PBFL (Green line, upward triangle markers):**
* **Trend:** A steady decline that accelerates slightly after 30%.
* **Approximate Data Points:** (0%, ~95%), (10%, ~93%), (20%, ~91%), (30%, ~87%), (40%, ~83%), (50%, ~79%).
6. **FoolsGold (Brown line, downward triangle markers):**
* **Trend:** A moderate decline until 30%, followed by a steeper drop.
* **Approximate Data Points:** (0%, ~95%), (10%, ~93%), (20%, ~90%), (30%, ~86%), (40%, ~80%), (50%, ~75%).
7. **Biscotti (Gray line, star markers):**
* **Trend:** The steepest and most severe decline of all methods. It begins to drop sharply after 20%.
* **Approximate Data Points:** (0%, ~95%), (10%, ~93%), (20%, ~90%), (30%, ~86%), (40%, ~77%), (50%, ~65%).
### Key Observations
* **Performance Hierarchy:** At a 0% attack ratio, all methods start at nearly the same high accuracy (~95%). As the attack ratio increases, a clear performance hierarchy emerges: **Ours > Median > FedAvg ≈ ShieldFL > PBFL > FoolsGold > Biscotti**.
* **Divergence Point:** The significant divergence in performance begins around an attack ratio of **20%**. Before this point, the lines are tightly clustered.
* **Most Robust:** The method labeled **"Ours"** is the most robust, maintaining accuracy above 90% even at a 50% attack ratio.
* **Most Vulnerable:** The **Biscotti** method is the most vulnerable, suffering a catastrophic drop to approximately 65% accuracy at a 50% attack ratio.
* **Clustering:** FedAvg and ShieldFL perform very similarly throughout the range. PBFL and FoolsGold also follow similar trajectories until the final data point.
### Interpretation
This chart is likely from a research paper proposing a new federated learning method (labeled "Ours") designed to be robust against adversarial attacks or Byzantine faults. The "Attack ratio" represents the proportion of malicious or faulty clients in the federated learning network.
The data demonstrates that the proposed method ("Ours") significantly outperforms six established baseline methods (FedAvg, ShieldFL, PBFL, Median, Biscotti, FoolsGold) as the environment becomes more hostile. The key finding is that while all methods degrade, "Ours" degrades at a much slower rate, suggesting it incorporates a more effective aggregation rule or defense mechanism.
The poor performance of Biscotti at high attack ratios indicates its specific vulnerability to the type of attack simulated here. The relative ordering of the other methods provides a benchmark for comparing their inherent resilience. The chart's primary purpose is to visually and quantitatively argue for the superiority of the authors' proposed solution in maintaining model accuracy under adversarial conditions.