Coder Lee Yongho Chapter 45

JULY 5, 2016 CHAMBER 9 COMMENTS

“The Pearson correlation coefficient is a general formula to calculate the relation between two variables. The formula you’re seeing now is that”
The formula on the blackboard was the one he definitely saw in his high school or university. It was composed of fractions and sigma, + and -, etc.
However, YongHo, who was learning, understood it differently.
ΦЖЙЪЛЛЦГБвОО
Illegible.
It was made of contents that YongHo didn’t even see in algorithm lecture in his college days.
It was no wonder. The things Son SeokHo was explaining were contents you would learn in statistics.
“I, is that so.”
YongHo first nodded his head as if he understood.
Son SeokHo, who usually acted like a next-door uncle, chewing on his sweet bean bread, didn’t allow a speck of flaw in regards to programming.
You don’t understand? Then do it until you understand.
He was really obstinate with it.
“Really? You understood? What did I just say?”
“Something about the degree of change between X and Y and… I, I don’t understand……”
He spoke a few lines and eventually stopped. YongHo’s voice didn’t have any confidence. He even felt sorry towards Son SeokHo who was teaching him pa.s.sionately.
“It’s the first time so it’s understandable. You don’t need to accuse yourself so much.”
“But… Are there lots more of things like these?”
It was to the point that YongHo was confused whether he was a programmer or a mathematician. In the last few days, most of the explanation was about what kind of algorithms were in it rather than understanding of the program.
And algorithms were composed of mathematical formulae.
These were thing he saw for the first time, so he needed time to learn these things.
One day was restricted to 24 hours so he could only reduce his sleeping time.
“We haven’t even started yet. We still have lots left such as euclidean distance, cosine measure similarity, etc.”
Son SeokHo looked at YongHo delightedly like an excited little kid.
Of course, YongHo was having fun. He was learning new things, and looking at the formulae actually being applied to a program was a refreshing experience for YongHo, moreover, there were not many chances to learn from a top-tier programmer directly.
However, he couldn’t ignore the reactions given out by his body.
Sleeping so little everyday made his eyelids heavy.

Big scoop.
The next day, when YongHo came into the office, a poster t.i.tled ‘big scoop’ was stuck on his desk.
Below the t.i.tle of big scoop was a huge printed photo of YongHo dozing off.
Son SeokHo had secretly took a picture of YongHo dozing off.
After he looked at the picture, YongHo was scared out of his wits and looked towards Son SeokHo.
“H, head researcher…”
Son SeokHo made an evil smile while looking at such YongHo.
“Well then, we now have Mr.YongHo’s weak point, so shall we work harder than yesterday?”
Gulp.
YongHo swallowed dry saliva.
Even last night, he left work late and due to learning all the algorithms taught by Son SeokHo, he only slept about 3 hours before coming to work.
His body was as heavy as a mountain and it was to the point that he started hearing buzzing sounds in his ear.
“O, of course.”
YongHo’s voice trembled thinly.
The delight of having his ability increase and the efforts he put in to meet up his expectations – all these were about to be crumbled in front of fatigue.
“Here, have one.”
YongHo thought that he would receive another sweet bean bread.
The sweet bean bread that Son SeokHo always had in his mouth.
However, this looked different from the outside.
In the transparent vinyl bag was not something that colored light brown but some kind of a box.
“Put it in your drawer before other people come to work and take them from time to time.”
Inside the box was a bottle of health supplements. It was obvious that it was expensive.
YongHo couldn’t accept it easily.
“Quickly.”
“Th, thank you.”
“I know you are working hard.”
All other things were unnecessary. Just saying one line: ‘you’ve worked hard’ was enough.
The block of lead which was holding him down disappeared in no time.

The time to learn about the algorithms used in maut was over.
And YongHo knew well that that wasn’t the end.
After the algorithm learning was over, explanations for installingmaut and explanations about the provided API ensued.
After that could he try downloading maut.
Maut was not over by just downloading the program.
Just the dependencies (libraries needed to run the program) numbered seven.
The bugs that occurred while installing were bonuses.
He installed the program and he downloaded the current code and tried running it.
The results appeared on the console window of eclipse.

RMSE Score : 0.9014 (+5%)

It was the efficiency score for the current library.
The one NetFlax opened to the public for the compet.i.tion had an RMSE score of 0.9525.
The recommendation system was better if the score was lower.
The efficiency was better by 5%. However, no further progress was made from this 5%.
Son SeokHo murmured while looking at the results on the monitor.
“We’ve improved it by 5% but we need to bring this number up to 10%.”
“10%, that means……”
“About 0.8659.”
“Will I be able to do it?”
In YongHo’s perspective, this was impossible. The smart shopping strategy team improved this by 5% by working on it starting from last year.
Countless people with doctorates may not be able to accomplish this.
Moreover, YongHo was still in the process of learning the related knowledge.
It was May.
The deadline to hand in the final result to the NetFlax Prize was at the end of September.
Asking whether this was doable in 4 months was understandable.
“We can do it if we do it together.”
YongHo looked at Son SeokHo’s face.
In his two eyes were belief that he could accomplish it.
‘We can do it.’
Inside YongHo’s head, too, such belief was starting to take root.

The business firm to implement Shinseki’s recommendation system, i.e. PS system was decided.
Mirae IT.
It was a company that YongHo knew well.
They would decide on the final system after running it alternately for two months and see which system produce more profit: the system implemented by Mirae IT and the system developed by the smart shopping strategy team.
The talks which were under wraps became official.
The schedule started in the middle of September and ended in November.
It was evaluated by calculating how many of the customers bought the recommended item recommended by each system.
There was only 4 months left.
The smart shopping strategy team was in chaos as if they were struck by lightning.
“Is it alright to not help?”
Unlike when YongHo entered the company, the team’s atmosphere changed drastically.
Everybody was in a state of crisis, and they became more sensitive.
Especially, rumors that this team would disband if this was unsuccessful.
If the team was disbanded, it was obvious what kind of treatment the members would get.
Their performance evaluation would plummet and the members would be re-located to different teams.
And be isolated.
There were allies who worked together with blood and sweat so no team leader would welcome a person from another team.
“Continuing with this is helping the team.”
Even in this atmosphere, YongHo and Son SeokHo put all their efforts into the NetFlax Prize.
It was only possible because of Jeong DanBi’s consideration. However, such consideration was bound to earn others’ jealousy.
They didn’t show it explicitly due to Son SeokHo being around, but their positive att.i.tudes were gradually changing.

In the office, it wasn’t that everybody worked on their task.
To work, there were few basic things that were necessary. From basic cleaning and drinking water, pens and notepads and other miscellaneous equipment were usually prepared by the youngest.
When he just entered the company, the office employees weren’t so picky.
Just because the water ran out, or some equipment was insufficient, people didn’t make a fuss about it.
But it wasn’t like that now.
They were similar words but accenting on different syllable, the tone changed greatly.
“It would be great if you could refill the water”
“The equipment ran out.”
It had respect towards YongHo.
“Mr. YongHo, why don’t you refill the water, it ran out, you know?”
“Did you order that equipment?”
It was hinted with annoyance.
The tight development schedule, and the sense of crisis due to the danger of disbanding were ruining the team’s atmosphere.
At the center of it all was Heo JiHoon.

The PM for implementing the PS system to go against Mirae IT was Heo JiHoon.
Jeong DanBi’s right hand man and a talent that graduated Hankuk university.
“Is the development done?”
“N, not yet.”
“What are we supposed to do if the synchronization module isn’t finished yet!”
Heo JiHoon even raised his voice while pointing towards one wall of the office.
“Can’t you see that there? There is a mountain load of things to do in the recommendation engine, from developing the final API to the testing.”
The post-it that was on the wall was the software development methodology that Heo JiHoon introduced ambitiously.
Agile software development.
If the traditional waterfall model or the helix model was a method which centered around doc.u.ment-based development, agile was the other way round.
It progressed with developing the program first and fix the things later as the problems occurred.
To say it simply, software development which was plan-centered would become development-centered.
“…I will finish it even if I have to stay up all night.”
The developer standing in front of Heo JiHoon spoke as he stuttered.
“Prepare yourself if it isn’t done by tomorrow morning.”
The agile methodology was a colorless spectacle.
The latest software development methodology was introduced but the actual development process didn’t change at all.
The manager would drive the developers hard, and the developers were chased by the schedule.
No latest development methodology could shorten a development time which needed at least 1 year into 4 months.
But it needed to be done.
Such was the reality of Korean developers.