Professor Ahn Su-yeon’s Office Hours

Professor Ahn Su-yeon’s office.

Tap, tap, tap.

The sound of typing finally stopped when Ahn Su-yeon, who had spent a long while giving feedback on Kim Dohyun’s report, paused with her hands resting on the keyboard.

This should be enough.

Click.

At last, she pressed Enter and leaned back deeply in her chair, stretching with a long sigh. She rolled her stiff neck and checked the time, only to realize that two hours had already slipped by.

"Good..."

She skimmed the screen with a satisfied look.

If it’s Dohyun, he’ll learn a lot from this feedback.

Even as she thought that, another idea surfaced.

But... is it really right to give him this kind of feedback during class?

Ahn Su-yeon rested her chin on her hand and fell into thought. The feedback she had written on Kim Dohyun’s report was far too advanced for a first-year general education course called Introduction to Computer Engineering.

At minimum, it was the sort of topic you’d cover in an upper-level major class for third- or fourth-years—maybe even only in a graduate seminar.

It doesn’t fit the class at all. If I bring this up in a first-year lecture, the other students will only feel out of place.

More than anything, though, she worried about Kim Dohyun himself.

It wouldn’t be good for the student to stand out too much either.

If it became publicly known that a brand-new freshman had written a report too advanced for most third- and fourth-years to understand, he could easily get labeled as a show-off.

...I was like that too, once.

As ‍‍‌‌⁠​​⁠‌​​‍​​‍​‌​⁠‍‌‍⁠⁠‌⁠‌‍‌‍‌‌‌‍⁠​‌​‌​‌‍‌‌‌⁠‍​​‌‍⁠‌‌⁠⁠she thought it over, Ahn Su-yeon changed her mind.

The rule is to give feedback on every report quickly in class, but... for Kim Dohyun, it would be better to call him in separately and talk. That would be easier for me to explain anyway.

Having made her decision, Ahn Su-yeon lifted the receiver without delay and called her teaching assistant.

"Yes. By any chance, do you know the number for first-year student Kim Dohyun?"

"Then please contact him and ask him to come to my office."

"If possible. If he has class or isn’t on campus, tell him to come by Friday instead."

"Yes, thank you."

Click.

After setting the receiver down, Ahn Su-yeon’s eyes sparkled with anticipation.

She could already imagine the expression on that brilliant student’s face when he saw the perfect feedback she had prepared.

Just thinking about it was entertaining.

Thursday, 4 p.m. The lectures for the day—major classes in the morning, general education classes in the afternoon—had finally ended.

Thursdays are awkward, so I used to skip going back to my room and just ate lunch with the others... but maybe because the classes are easy, I’m not really tired.

With that thought, I left the lecture hall with my classmates.

"Wow, finally. Tomorrow’s a free day. I’m saved, seriously."

"What good is a free day if there’s the opening ceremony in the afternoon? We still have to come to campus anyway."

"Ah, right. The opening ceremony... the upperclassmen will all be there, won’t they?"

"Of course. But I heard Senior Jinwoo got rid of the whole 'drink a ton in our department' thing?"

"Seriously?"

"Yeah. Something like, 'I don’t stop the women who leave, and I don’t block the women who come in.' Supposedly it’s the same with alcohol."

"What the hell does that even mean?"

"Basically, if you want to drink, drink, and if you don’t, don’t. Senior Jinwoo said the upperclassmen really forced a lot of alcohol on him when he was ‍‍‌‌⁠​​⁠‌​​‍​​‍​‌​⁠‍‌‍⁠⁠‌⁠‌‍‌‍‌‌‌‍⁠​‌​‌​‌‍‌‌‌⁠‍​​‌‍⁠‌‌⁠⁠a freshman, so it was rough."

Then my classmates’ attention turned to me.

"Dohyun hyung, you’re coming tomorrow too, right?"

"Yeah, I have to go."

Though I wasn’t planning to drink much at tomorrow’s department gathering.

Hyung said he’d be going around to the other departments to greet people.

Apparently, that was just what the department head did.

We were chatting idly as we headed out of the building when—

Jing— jingle~.

My phone vibrated briefly in my pocket.

[02-XXXX-XXXX]

It was an unknown number.

"Hello?"

— Ah, is this Kim Dohyun? This is the computer engineering department TA.

"Ah, yes. Hello."

— Are you on campus right now, by any chance? Your schedule suggests that you are.

A schedule? He must be looking it up from the department office.

"Yes, I’m on campus. I just finished class."

— Perfect. Professor Ahn Su-yeon would like to see you for a moment. Can you come to the engineering building now? You know where the department office is, right? Come there and I’ll take you over.

Professor Ahn Su-yeon?

At once, last week’s assignment flashed through my mind.

Probably because of the report, right?

Zero answered my thought.

Teach me, huh...

"Understood. I’ll head over right away."

— Yes.

After hanging up, I turned to my classmates.

"I’ve got to stop by the department office for a second. The TA wants to see me, so you guys go on ahead."

I gave them a casual excuse and adjusted my bag on my shoulder.

"Huh? Okay, hyung. See you tomorrow!"

"Yeah, see you tomorrow."

After sending my classmates off first, I turned and headed for the engineering building.

When I arrived in front of the department office, our department TA was waiting for me.

He looked at me and gave a brief nod.

"You’re here? Professor Ahn Su-yeon’s office is kind of tucked away, so it’d be hard to find on your own. Follow me."

"Yes."

The TA walked ahead without any extra explanation.

As we made our way down the hallway, he kept sneaking glances at me.

It was probably strange to him that a freshman—especially one this early in the semester—had been summoned privately by a professor.

Even so, he muttered something like, "But the professors have an event and a dinner later today, don’t they...?"

"Here it is."

The TA stopped in front of a door with a sign that read Professor Ahn Su-yeon’s Office.

"Go on in."

"Yes."

I straightened my clothes lightly, took a short breath, and knocked.

Knock, knock~.

"Come in."

When she heard movement beyond the door, Ahn Su-yeon straightened in her seat.

The door opened, and a fresh-faced male student walked in—Kim Dohyun.

"Hello, Professor."

"Yes. Sorry to call you here so suddenly."

"Not at all."

His voice, his manner—everything about him was extremely polite.

And seeing how passionate he was about his studies, and how popular he seemed among his classmates when she had seen him in lecture, he struck her as a remarkable student indeed.

"Why don’t you sit here?"

When Kim Dohyun took the seat she offered, Ahn Su-yeon gently slid ‍‍‌‌⁠​​⁠‌​​‍​​‍​‌​⁠‍‌‍⁠⁠‌⁠‌‍‌‍‌‌‌‍⁠​‌​‌​‌‍‌‌‌⁠‍​​‌‍⁠‌‌⁠⁠the papers she had placed at one side of her desk toward him.

It was a document filled with her feedback on Kim Dohyun’s report, prepared with all the care she could give it.

"I read your report very interest-ingly. It was excellent—so much so that it was hard to believe a first-year wrote it."

Ahn Su-yeon offered her praise in a deliberately calm voice.

But now it was time to give feedback as his teacher.

"Still, there were a few places where you overlooked some realistic constraints, so I wrote down some notes."

"Feedback, you say?"

"Yes. Normally I’d give it during class, but this material is a bit too difficult for a first-year lecture. It would also take quite a while. Take a look, and if anything doesn’t make sense or you have questions, ask me now."

Kim Dohyun picked up the report.

His gaze lingered on the section Ahn Su-yeon had painstakingly marked most heavily: Overlooking Battery Drain in a 3G Network Environment.

"..."

Watching him study her feedback so carefully, Ahn Su-yeon expected him to become flustered, or perhaps lower his head in embarrassment.

Or maybe she expected a pure, curious reaction—some innocent confusion as he wondered what exactly her feedback meant.

But then—

"Professor, thank you for the feedback... but."

Kim Dohyun’s expression, with that final but hanging at the end of his sentence, was unnervingly calm.

"The battery drain issue you pointed out could definitely be fatal if we used a fixed-interval method."

"Right? Engineering isn’t about theory, it’s about reality. If you keep sending signals to the server every five or ten seconds just to maintain a connection, the smartphone battery will leak away fast."

"..."

"But to understand that immediately is impressive. Even third- and fourth-years would have trouble with it."

Ahn Su-yeon was praising him sincerely. To catch her feedback in a single glance...

As expected, he really did read all those ‍‍‌‌⁠​​⁠‌​​‍​​‍​‌​⁠‍‌‍⁠⁠‌⁠‌‍‌‍‌‌‌‍⁠​‌​‌​‌‍‌‌‌⁠‍​​‌‍⁠‌‌⁠⁠materials before writing the report.

And yet—

"Yes. As you said, continuously sending signals to the server on a fixed schedule would be inefficient. But what if we don’t fix the interval and instead make it variable?"

"...Variable?"

Ahn Su-yeon’s brows drew together slightly.

For a moment, she simply didn’t understand what the student was saying.

"Yes. The amount of time a connection stays alive varies from carrier to carrier and base station to base station. Some places will tolerate five minutes of silence, while others will cut the connection without hesitation after just three."

"That’s true. It depends on the carrier."

"So there’s no need to send a signal every ten seconds. The smartphone application itself can quietly figure out how long this base station or carrier usually waits before dropping the connection, then time it, and only send a survival signal one second before the connection is cut."

Kim Dohyun’s voice was as respectful as ever.

But the content of what he was saying was an intricate solution that technically sidestepped the very "real-world limitation" she had pointed out.

"At first, it sends signals at short intervals, then if the responses succeed, it increases the interval by ten percent at a time to find the threshold. After that, if you analyze user patterns with an algorithm and train it to learn the optimal interval..."

Dohyun met her eyes with a look of quiet certainty.

"You can drastically reduce unnecessary power consumption and still keep the connection alive without interruption."

"Then I think the realism issue you were concerned about would also be solved."

"...?"

Ahn Su-yeon’s mind stopped for a moment.

Just as she was about to open her mouth to object, her brain began chewing on Dohyun’s logic and running a simulation at a ferocious pace.

...Wait. You learn the timeout and then calculate backward from it?

A virtual circuit diagram and packet flow chart began taking shape in her head.

If the old method was the smartphone blindly checking in with the server over and over again, then this student’s method was more like the phone measuring exactly when the server would close, then sliding one foot in just 0.1 seconds before the door shut.

Theoretically... perfect.

The base station’s session expiration time would be learned by both the app and the device itself.

Then, only at that exact moment, it would send the minimum necessary packet.

That meant there was no need to keep waking the wireless chipset inside the phone all the time. The standby mode could be preserved for as long as possible, and the device would only need to wake once every 4 minutes and 30 seconds, or perhaps every 5 minutes.

Then... battery efficiency would improve by at least ten times, maybe twenty depending on the situation.

This wasn’t just an abstract idea. It was the kind of insight that could only come from a complete understanding of the characteristics of networks and mobile communication systems.

Is this technically possible...? It’s difficult, but maybe not impossible.

But what mattered to Ahn Su-yeon right now wasn’t technical verification.

He... thought of this as a first-year? In that tiny conversation just now?

Ahn Su-yeon stared at Kim Dohyun with a dazed expression.

The student sitting across from her only looked placid.

She had seen countless prodigies while studying over the years.

She herself took pride in being intelligent.

But this kind of intuition was something beyond that.

...Click.

Without realizing it, Ahn Su-yeon uncrossed her legs and looked at Kim Dohyun as she thought to herself.

A genius... maybe?

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