Coder Lee YongHo – Chapter 48: One Shot Two Kill (1)

Kim ManHo laughed and it resounded across the whole office.
“You are sure of it, right?”
“Yes. I’m completely sure. The performance is incomparable.”
“Yes, very good. You’ve done very well, so let’s keep it up for a little while.”
The contract for the PS System was right in front of his eyes.
Continuing from KO Telecom’s K-recommendation system, if he could obtain Shinseki group’s PS System contract, then Kim ManHo’s position in Mirae IT would shoot up so that nobody would be able to touch him easily.
“But the developer who is working for us is requesting danger pay since it seems like a team leader-level personnel would join.”
“Team leader?”
“He’s called Son SeokHo, and I’ve told you before.”
“Son SeokHo?”
Kim ManHo didn’t seem to remember. The reporting man looked at Kim ManHo’s mood for a while when he continued the explanation.
“It’s a person team leader Jeong DanBi scouted when making the team. He graduated from correspondence college and worked as a freelancer before going to Shinseki. He has experience in working in IT labor union.”
“Oh, you mean that commie.”
“This… It seems like he has quite the ability since he could identify the problem with our system.”
“So, how much do they want.”
“100 million (≈85000 USD) along with a team leader-level position.”
Kim ManHo seemed to ponder since he was gripping and loosening his fist.
“How much do we have from gathering from our cooperative companies?”
“A little over 100 million.”
“Say it’s a deal. But, make sure to add in the condition of when the work is completely finished.”
“I understand.”
Along with interfering with the opponent, he had to prepare his work flawlessly. That was one of the driving power behind Kim ManHo’s rise from an ordinary employee to a director.
“There’s nothing wrong with the demonstration right?”
“Yes. An ByungHoon is an open source contributor. And it seems that it’s a source related to recommendation too.”
“If this goes well, then promote him in the next personnel management season.
He couldn’t stop smiling even until the end of the conversation.


YongHo organized his finding on the bug window on a notepad.

Cases where the bug window recognizes something as an error.
Problems with performance.

  1. There is an inefficiency in performance.

Problems with logic (A precondition is needed)

  1. A program specification document, in which the input and output is stated, is necessary.
  2. It needs to be compiled at least once.

Normal errors.

  1. Occurs when an Exception occurs.

Applying the rules of the bug window, there was no output stated in the document.
RMSE Score : 0.8659
YongHo added the wanted value to the document.
And clicked the shortcut key to run the java program.

Title : Tuning of the collaborative filtering (a theory that is used a lot in recommendation algorithms) of the maut system
Content : The system performance is not meeting up to the user’s requirements due to the first-rater problem or the cold-start problem which is a problem in collaborative filtering.
Result : Various algorithms, including classification and singular value decomposition should be used in combination.
The details are as follows.

The bug window alarm didn’t end with just tens of lines. It was filled with words YongHo saw for the first time and it was going over 2 digits like it was nothing.
‘Now I just have to follow this instructions, huh.’
YongHo’s eyes started shining more than ever.
He had found the answer.
And all he needed to do now was to follow what it says. YongHo’s hands started moving faster than his eyes.


Seattle, America.
3 men were sitting in front of a computer.
Team name : The Dessert.
It was the team currently running first for the NetFlax Prize.
“Dave, how is it?”
“We’re first, of course.”
Dave, with curly blond hair, spoke while smiling as if it was obvious.
RMSE Score : 0.8669 (+9.8%)
Through consistent algorithm tuning, he was renewing the record every day.
“It seems difficult to go over 10%, right?”
“Raising it by 0.2% isn’t easy as it seems.”
“This is good already. We’re higher than the last year’s winning team.”
“You’re right. Last year, they only got this far through collaborating.”
It was one of the methods that the winning team for the NetFlax Prize used.
Combining algorithms that other high-level teams used by sharing algorithms that they used – this method was used to achieve a 9.5% increase in performance.
Even they didn’t break through the 10% boundary. There was never a team which broke through the 10 % boundary in the past 5 years.
The winning team with 10% increase in performance will receive twice the amount of 1 million dollars – 2 million dollars, called the Grand Prize.
The 10% milestone that the hosts set seemed easy to break at first but it was now known as the unsurpassable wall.
It seemed like it would be achieved but couldn’t so it stirred the hearts of many challenge-seeking people.
“Let’s do it by ourselves first.”
The sparkling night scenery of Seattle which would captivate any gaze.
The people concentrated on their work without the time to be captivated by such a beautiful scenery.
It was a sleepless night of Seattle.


Even Seoul wouldn’t lose out to any city in the world comparing night scenery.
Inextinguishing lights of the office buildings was the driving force of growth.
“It’s done.”
While stretching his arms out, YongHo stood up from his seat.
RMSE Score : 0.8669 (+10.0%)
On the eclipse window, the number which Son SeokHo and YongHo dreamed of was printed.
“I, is that true?”
“Yes, head researcher.”
His skin was all rough due to not sleeping but his eyes were shining brightly. It wasn’t the eyes of a liar.
Son SeokHo was looking at the screen YongHo indicated.
RMSE Score : 0.8669 (+10.0%)
Son SeokHo rubbed his eyes as if he couldn’t believe it.
“N, no way.”
“It was really hard. I thought I would die.”
“How, How did you do it?”
Son SeokHo’s voice was trembling. It was Son SeokHo who never lost his composure. It was he who even acted without restraint in front of Jeong DanBi.
Delight which filled his body was enveloping Son SeokHo.
“This is the way i did it, first I…”
YongHo started explaining the contents of the bug window.
The shocked mouth never closed.
The expectation he had when YongHo fixed the transaction error all seemed to crumble when looking at this code.
However, it wasn’t.
YongHo was a diamond.
He wasn’t a source stone that one needed to refine, but he already was exuding his value.
That day, the number one for the NetFlax Prize changed.
Team name: Shinseki Maut.
It was the name of the team which was newly added to the Leaderboard of the NetFlax Prize.


Growth of distribution companies were slowing down.
The main markets, such as department stores and discount stores, had their sales growth visibly shrinking.
In contrast, the sales in online shopping was increasing explosively.
20%, 30% growth a year.
Distribution service-based companies like Shinseki had to follow the trend. That’s why the PS(Preference Shoot) System was suggested.
I will shoot the customer’s preferences.
A interim report-like demonstration day, which should shoot the chairman’s preferences, instead of the customers’, began.
“Then we will first look at the presentation materials Mirae IT prepared.”
It was decided that they would select the system with more sales by letting the system being developed by Jeong DanBi’s team and the system being developed by Mirae IT compete with each other.
Today’s presentation had the characteristics of a interim report before the actual competition.
Paper competition.
Mirae IT’s presentation started where important personnel from each company were gathered.
An ByungHoon, who works as an open source contributor for open source maut.
The know-how piled up from managing KO Telecom’s recommendation system.
These two things were the strengths that Mirae IT was emphasizing.
“Smart shopping strategy team, please prepare.”
Jeong DanBi stepped up.
The first screen was very provocative.
In the middle of the big screen was just one number.
“We can’t survive now by striving to be first. We need to start off as first.”
And the next screen was the Leaderboard noticeboard for the NetFlax Prize. There was 2 weeks until the final result but they were 1st right now.
Team name : Shinseki Maut.
“Currently, our recommendation engine is running first in a global-scale recommendation system competition known as the NetFlax Prize.”
Chairman Jeong JinYong, who was watching from the middle, changed his expression.
He was showing interest in Jeong DanBi’s presentation. And Jeong JinHoon, who was watching next to him, had his face turn stiff for an instant before turning normal again.
“Did Mirae IT say that they had an open source contributor for open source maut? Then we have a committer. There may be people who already know this, but to become a contributor, one needs an approval from a committer. Meaning that head researcher Son SeokHo approved manager An ByungHoon to participate in this project.”
As Jeong DanBi’s continued her presentation, the faces of the people from Mirae IT, became rotten.
“The era of fast follower is gone. Now, we need to become the first mover. Our PS System will pave the way.”
The winner for the interim report, aka the paper competition, was clear to everyone.
Just that some people couldn’t acknowledge it.


After the presentation ended, An ByungHoon offered his hand to YongHo in gladness after finding him.
“Oh, manager.”
However, the gladness eventually turned into self-guilt.  From the paved cheeks and the grabbed hand, he could feel the boniness.
“You… How much did you work in order to become like this?”
An ByungHoon could ascertain YongHo’s state with a glance. He knew better than anyone the process of how a person changed due to frequent night-shifts and over-night work.
The current YongHo was exactly like that.
“I’m alright. It’s not that hard.”
An ByungHoon threw a line with a worried face.
“That’s why I to come under me. I would have never let you become like this.”
YongHo’s face had gone bad.
It was like a rotten apple.
In compensation for the position of 1st, he had to pay with his health.
“It isn’t because he was under me. Please don’t misunderstand.”
“H, head researcher.”
Son SeokHo who was listening to this conversation stepped in.
Today, for once, he wasn’t eating sweet bean bread.
But the bad expression seemed like he had a sour mood.
An ByungHoon was flustered at those words.
“Ah, I didn’t mean that.”
“Nice to meet you. I’m called Son SeokHo. Meeting offline like this is a first. Sir coffee.ahan.”
“Then, you are sir maut?”
Coffee.ahan was the nickname An ByungHoon used while acting as an open source contributor.
It was the meeting of the committer and contributor for the open source maut project.

Translator’s note


Mirae just got owned lol. And such domineering words by Jeong Danbi there…

Look forward to Dave’s personality lol. He’s SOOOO funny.

Oh, and don’t forget to read the new project, God of Music here at Kobatochandaisuki! – That aside, a funny thing happened on NU. I submitted GoM as a new series… and guess what they did. They put God of Cooking as a related series LOL! (It wasn’t me) And lol, I guess it’s similar… with time-backs and all…

Have a nice read!

Translator : Chamber

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11 thoughts on “Coder Lee YongHo – Chapter 48: One Shot Two Kill (1)

  1. Charles

    I think you made a mistake when yongho is seeing his results the second time you put rmse as 0.8669 and it should be 0.8659, minor error but if you can please fix it

  2. Charles

    I think you made a mistake when yongho is seeing his results the second time you put rmse as 0.8669 and it should be 0.8659, minor error but if you can please fix it, this happens all over the explanation of yongho to his project leader (twice on the third segment of the chapter)


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