Chapter 273: Baselines and Glitches

The progress bar froze at seventeen percent, and the log window in the lower right corner of the screen began to scroll. Lin Chen stared at the three waveform graphs, keeping his breathing very light. The air-conditioning in the teaching room was turned up high; cold air poured in through his collar, and the old injury in his left foot started to tighten again. He did not move. He only rested his right hand on the edge of the table, rubbing the rough wood grain with the pad of his finger.

The algorithm was slicing in the background. The raw data had not been preprocessed at all. Baseline drift rose and fell like waves, and electromyographic artifacts were as dense as weeds. V1.2's filtering module began to work, first cutting away power-line interference above fifty hertz, then using wavelet transforms to peel off low-frequency noise. The waveforms on the screen gradually became clearer, though they were still rough. Su Man stood beside him with a stopwatch in her hand, her gaze moving back and forth between the engineering prototype and Director Zhao. Director Zhao said nothing. He only leaned back in his chair, tapping the tabletop lightly with his fingers. The rhythm was very slow, as if he were weighing time itself.

When the first data stream reached forty-three percent, the warning module suddenly threw up a yellow marker. Lin Chen's heart tightened. He immediately pulled up the original segment and zoomed in. It was poor electrode contact caused by the patient turning over; the waveform had formed an instantaneous cliff. The algorithm had identified it as the beginning of a high-frequency cluster. A false alarm. His finger hovered over the keyboard, but he did not press pause. The rules had already been locked. Any temporary intervention would destroy the continuity of the queue. He watched the yellow marker remain in the log for two seconds before the smoothing logic of the sliding window covered it, and the marker disappeared. The confidence score fell back to 0.68. Safe.

The second data stream entered its core segment. Irregular sharp waves began to appear, their frequency slowly climbing. Lin Chen's pupils contracted slightly. This was a typical precursor of focal discharge. The algorithm's confidence curve began to rise: 0.71, 0.74, 0.78. The threshold was set at 0.75. A faint blue glow appeared at the edge of the screen. The warning had been triggered. Lin Chen looked up at Director Zhao. Director Zhao was already on his feet, walking to the bedside monitor. He glanced at the real-time EEG, then at the wall clock. Three minutes. The lead time given by the algorithm was four minutes and eleven seconds. Director Zhao said nothing. He simply reached out and adjusted the position of a lead wire, confirming that the signal had not attenuated.

A sharp stab of pain shot through Lin Chen's left foot, like thin needles driving upward along his Achilles tendon. He clenched his back teeth and shifted his weight half an inch onto his right leg. Su Man handed him a cup of warm water. He did not take it; he only shook his head. He could not afford to be distracted now. The third data stream had already loaded to eighty percent. This waveform was even messier, mixed with severe respiratory artifacts and ECG interference. The algorithm oscillated repeatedly between 0.72 and 0.74, never breaking through the threshold. Lin Chen knew this was the latency period of an atypical seizure, with its features concealed by noise. He could not change the parameters. He could only wait. Engineering was not a wishing well; it was a sieve for probability. In low-frequency mode, linear interpolation was silently filling in missing sample points in the background. A delay of 0.1 seconds was like an invisible levee, holding back the data gaps caused by voltage drops.

The progress bar reached ninety-nine percent. A red line suddenly appeared in the log window: Warning triggered. Confidence 0.76. Lead time 3 minutes 58 seconds. Almost at the same moment, hurried footsteps sounded from the corridor outside. Director Zhao pushed open the door, glanced toward the monitoring room, then came back. He picked up the pen on the table and drew a circle at the edge of the third waveform graph. "The electromyographic interference is too heavy, but your interpolation compensation filled in the breakpoints." His tone was calm, revealing no emotion. "One false alarm, zero misses. The lead time is within a clinically acceptable range."

Lin Chen loosened his clenched right hand. His palm was covered in sweat. He slowly sat up straight, and when his left foot came down onto the floor, the pain became clearer instead. "What is the filing process?" he asked. Director Zhao pushed the document envelope toward him. Inside were two ethics review forms stamped with the hospital seal and a clinical trial filing receipt. "Copy the desensitization protocol and the raw logs for me before the end of the day. Next week it goes through the ethics committee as a formality. Once the formality is done, the device can enter neurology for a small-sample control study." He paused and looked at Lin Chen. "But you need to understand that filing is only an admission ticket. Multicenter trial data, a medical device registration certificate, and the follow-up costs afterward—none of them can be skipped. Capital looks at statements. Hospitals look at human lives. Don't narrow the road yourselves."

Lin Chen nodded and put the receipt into his backpack. Su Man had already started packing up the engineering prototype, her movements crisp and efficient. When they walked out of the teaching room, the light in the corridor had already dimmed. The four o'clock wind passed through the gaps in the inpatient building, carrying the chill of early autumn. Lin Chen took out his phone, and the screen lit up. There was one unread email. The sender was the legal department of Zhao Qiming's fund. The subject line contained only four words: Series A Term Sheet. In the attachment was a densely packed PDF: valuation adjustment clauses, board seats, technical exclusivity agreements. Line after line of black text spread out like a fence. Lin Chen stood at the stairwell and did not open it right away. He lowered his head and looked at his left foot. His shoelace had come loose. He squatted down and slowly tied it tight. His fingertips touched the rough upper of the shoe, and the sensation was real. He knew that the door of the teaching room had closed, and another door had only just been pushed open. And the wind behind that door was colder than the wind in the corridor.