BOUNDARY(9)

"So once the network's fully characterized, I start setting off the signal pulses. I let the network know"—he tapped his glasses and the virtual control interface that only he could see—"exactly what signal I'm about to send, then trigger it. The net records all the responses it can, I hit it with another pulse; maybe change modes, it starts building up a rough picture. I examine it, see if I've got something coming up. Maybe I go back, do a few more GPR or radio shots, or try another acoustic signal, or shift frequencies. Eventually, I've got all the data I think will be useful. Then I can really go to town on this stuff; sensor fusion, bandpass filtering, synthetic aperture, Kalman and Weiner filters, all that kind of thing, plus some tricks of my own.



"With a handful of these motes and no special signal generators, I can use the ambient sound to locate and determine the number, direction, and general composition of your tents—without any of my dust motes actually touching the tents. Heck, with equipment twenty years older, I could send any two of you off to have a conversation, and not only locate you, but pick out your entire conversation, whispered, on the other side of a hill three hundred meters off. These motes have access to my own neural net code, expert systems, fuzzy logic structures, all sorts of stuff in the control unit and local heavy-duty processors, like in the main control unit here."



He patted another simple metallic box on his belt. "Give me powerful signal sources, and I'll guarantee to map out anything you want, above or below ground. And in this case, I'll even guarantee that you'll have enough detail to count teeth in a skull."



"Can you keep a record of how you produce the results?" Helen asked.



"Not only can I," A.J. answered, pacing out the area again as though measuring it, "it's pretty much part and parcel of the process—nice alliteration there, huh? I keep the raw data and track the sequence of filtering and analysis, all the way in. I have to—sometimes you don't get the best results and you need to experiment by taking out one step, moving it to another point in the sequence, and so on. It can make a big, big difference in the final results whether you filter first and then run an enhancement process, or enhance first and then filter, for instance. Pillage, then burn, so to speak."



He stopped, nodded to himself, then turned back towards the tents. "Well, it's getting pretty dark out here, but rather than waste time, I'll just get started."





Jackie and Helen held the lights as A.J. unpacked a number of devices with thick, rugged power leads.



As he did so, Helen studied him, a bit surreptitiously. Somewhat to her surprise, she was starting to find the man interesting.



In many ways, A.J. Baker was obviously a classic geek. Who else got that enthusiastic about dry-as-dust technical matter? But the muscles visible in his arms when he hefted the first case—the one that had nearly pulled Helen's shoulder out of its socket—made it clear that A.J. was in far better physical condition than the average geek.



On a personal level, the muscles impressed Helen even less than the flamboyantly awkward geeky mannerisms. But she found the combination rather intriguing. It reminded her of . . .



Well, herself, actually.



Since Helen didn't have that damnable male ego to deal with— the one that crucified every high school geek in existence—her own mannerisms weren't as awkward as A.J.'s. At least, she hoped not. But she could get just as enthusiastic when discussing paleontological issues, which were often literally as dry as dust. And on the few occasions when she ventured into public gymnasiums for a workout, she usually got admiring looks from all the men present and envious ones from the women. Even from women half her age.



From men half her age, she always got admiring looks. Ogles, often enough, to call things by their right name.



The thought of young men rallied her. Stop this, woman. He must be fifteen years younger than you are.



Thus fortified, Helen went back to studying A.J. from the perspective of an expert in one field watching another at his own. She did her best to ignore the treacherous little voice at the back of her mind, as it worked its way through simple mathematics.



Don't be silly. He's not as young as he looks. Can't be, not even in his cutting-edge field. He's got to be at least twenty-five or twenty-six. Maybe twenty-seven. Subtracted from thirty-eight, that is not fifteen years younger. It's only eleven. Maybe even less.



Shut up.





"Okay, here we got your GPR unit." A.J. held up a wide metallic antenna unit, followed by a cylindrical object that looked like a solid rod of metal but probably wasn't. "And this here's the impactor for seismic signals, some electromagnetic pulsers—keep metal and electronics that aren't shielded well away, folks—and my own shriekers. High-power ultrasonic pulsers."