책 읽는 개발자

회귀분석이나 Machine Learning등에서 많이 사용되는 개념인 Likelihood(가능도) 에 대해 정리합니다. Likelihood(가능도) Definition 연속사건에서는 특정 사건이 일어날 확률이 0으로 계산됨. Likelihood(가능도)라는 개념을 적용하면 이를 비교할 수 있음. 즉, 연속사건에서 특정 사건일 때의 PDF 의 값을 Likelihood라고 볼 수 있음. ※ PDF의 값이 클 때 일어날 가능성이 높은 사건. ex) 아래 연속확률변수X의 PDF graph에서 X가 1일 확률은 0이지만, X가 1일 Likelihood는 0.2419707 이다. Characteristic Likelihood의 직관적인 정의 : 확률분포함수의 y 값 - 이산 사건에서는 Likelihood는 Prob..

Today I got up early. Maybe around 6:40 AM? Certainly sleeping early makes me wake up easily. I went to the company by the shuttle bus. The weather is sunny and I can breath well with a fresh air. I hope the air condition is continually going to be good. Last night, before I go to sleep, I read one article regarding one superious man who has over 30 university major. Even He is a pharmacist and ..

leetcode.com/problems/longest-common-prefix/ Longest Common Prefix - LeetCode Level up your coding skills and quickly land a job. This is the best place to expand your knowledge and get prepared for your next interview. leetcode.com Solution 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 char * longestCommonPrefix(char ** strs, int strsSize){ if(strsSize==0) return ""; char* rst = (..

Today I got up late, maybe around 7:30 AM? Yesterday, I was a bit tired but I got sleep late, so now I am not feeling good. I would like to take care of myself today. I went to the company by the subway, there were so many people who were going to somewhere. These days It seems that COVID-19 are still not decreased even after the Spring has come. I am very worried about the infection. Anyway I a..

Exponential Smoothing 의 이해를 위한 정리입니다. Moving Average Exponential Smoothing을 알기 위해 필요한 Moving Average에 대해 간략히 정리합니다. Simple moving average - 최근 기준 지난 N개의 실제 데이터의 산술평균을 차기의 수요량으로 예측하는 방법. - N의 값을 크게하면 산술평균과 유사해지며 작게할수록 최신수요량과 유사. Formula k개의 window를 쓴다고 가정했을 때, n번째의 SMA의 기본 Formula는 n-k+1부터 n번째까지의 산술평균이다. n+1번째의 SMA 값은 window 개수만큼 모두 계산하지 않아도 됨 n 번째 까지의 SMA 값에서 n+1 번째 관측치 값을 더한 후, n-k+1 번째 값을 빼기만 ..

모집단(Population)에서 표본(Sample)을 Random Sampling으로 추출하고, 추출된 표본에 대한 신뢰도에 대한 개념을 정리합니다. Sample(표본) Definition Sample(표본) = 모집단의 부분집합 모집단에서 크기가 n인 표본 \(X_{1}, X_{2}, ... X_{n}\) 을 임의추출 하였을 때, 표본평균 \(\overline{X}=\frac{1}{n}\sum_{i=1}^{n}X_{i}\) 표본분산 \(S^{2}=\frac{1}{n-1}\sum_{i=1}^{n}(X_{i}-\overline{X})^2\) 표본표준편차 \(S=\sqrt{S^{2}}\) Sample Mean(표본 평균)의 평균, 분산, 표준 편차, 표준 오차 Definition 모평균이 m, 모분산이 \(..

I woke up at 6:50 AM in the morning. It was a little bit tired because I slept late last night. I would like to sleep tonight. Anyway, I took a shuttle bus going to the company and I am having a meal now at the restaurant in the company. while I am having a meal, I read a book. I think I took my morning time worth. [SAVERS] silience - thinking nothing while taking a shower affirmation - I can do..

Let me write my miracle morning log. I got up around 6:45 AM in the morning. It was a little bit difficult to wake up because I slept late last night. So I think I need to get sleep early everyday but It is not easy to me. Anyway I went to the comapny by the shuttle bus. And I am having a meal at the restaurant in the company now. I wish there is nothing to bother me at work. [SAVERS] sileince -..

I woke up around 6:45 AM in the morning. So, I could go to the comopany by the shuttle bus safely. I took a time with my family and friend over the weekend. We got the my baby's 100 days celerbration party on Saturday. It was a little bit hard to take my son's photo smiling but It was fun and worth. On Sunday, My wife and I went to my friend's house. It's been a long time to meet each others. Th..

leetcode.com/problems/roman-to-integer/ Roman to Integer - LeetCode Level up your coding skills and quickly land a job. This is the best place to expand your knowledge and get prepared for your next interview. leetcode.com Solution 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 int romanToInt(char * s){ int value = 0; int cur; int old = 4000; while(*s){ if(*s=='I') cur =..