{"id":7631,"date":"2019-08-07T11:50:08","date_gmt":"2019-08-07T02:50:08","guid":{"rendered":"http:\/\/www.gisdeveloper.co.kr\/?p=7631"},"modified":"2020-05-28T10:20:14","modified_gmt":"2020-05-28T01:20:14","slug":"%ec%86%90%ec%8b%a4%ed%95%a8%ec%88%98loss-function","status":"publish","type":"post","link":"http:\/\/www.gisdeveloper.co.kr\/?p=7631","title":{"rendered":"\uc190\uc2e4\ud568\uc218(Loss Function)"},"content":{"rendered":"

\uc190\uc2e4\ud568\uc218\ub294 \ube44\uc6a9\ud568\uc218(Cost Function)\ub77c\uace0\ub3c4 \ud569\ub2c8\ub2e4. \uc190\uc2e4\uc5d0\ub294 \uadf8\ub9cc\ud07c\uc758 \ube44\uc6a9\uc774 \ubc1c\uc0dd\ud55c\ub2e4\ub294 \uac1c\ub150\uc5d0\uc11c \ub9d0\uc785\ub2c8\ub2e4. \uc190\uc2e4\ud568\uc218\uac00 \uc65c \ud544\uc694\ud55c\uc9c0\ubd80\ud130 \ud30c\uc545\ud558\uae30 \uc704\ud574 \ub2e4\uc74c\uacfc \uac19\uc740 \ub370\uc774\ud130\uac00 \uc788\ub2e4\uace0 \ud569\uc2dc\ub2e4.<\/p>\n

\r\nt = [0, 0, 0, 0.5, 0.5, 0, 0, 0, 0, 0]\r\n<\/pre>\n
\ucd1d 10\uac1c \uac12\uc73c\ub85c, \uc5b4\ub5a4 \uc785\ub825\uac12\uc774 0~9\uc911 \uc5b4\ub5a4 \uac12\uc778\uc9c0\ub97c \ub098\ud0c0\ub0b4\ub294 \ud655\ub960\uac12 \uc785\ub2c8\ub2e4. \uccab\ubc88\uc9f8 \uac12\uc774 0\uc77c\ub54c\uc758 \ud655\ub960\uc774\uace0, \ub450\ubc88\uc9f8\uac00 1\uc77c\ub54c\uc758 \ud655\ub960\uc785\ub2c8\ub2e4. \uc989, \uc704\uc758 \uac12\uc740 3\uc77c\ub54c\uc640 4\uc77c\ub54c\uc758 \ud655\ub960\uc774 \uac01\uac01 50%\uc778 \uc148\uc785\ub2c8\ub2e4.<\/p>\n
\uc704\uc758 \ub370\uc774\ud130\ub294 \ud56d\uc0c1 \uc633\uc740 \uacbd\uc6b0\uc758 \uc2e4\uc81c\uac12\ub77c\uace0 \ud569\uc2dc\ub2e4. \uc774\uc81c.. \uc544\ub798\uc758 \ub370\uc774\ud130\ub294 \uacc4\uc0b0\ub41c, \uc989 \uc608\uce21\ub41c \ub370\uc774\ud130\uc785\ub2c8\ub2e4.<\/p>\n
\r\ny = [0.01, 0.01, 0.1, 0.3, 0.33, 0.04, 0.02, 0.05, 0.01, 0.1]\r\n<\/pre>\n
\uc704\uc758 \uc608\uce21 \ub370\uc774\ud130 \uc5ed\uc2dc 0~9\uc911 \uc5b4\ub5a4 \uac12\uc77c \uac70\ub77c\ub294 \uacc4\uc0b0\ub41c \ud655\ub960\uac12\uc73c\ub85c\uc368 0\uc77c \ud655\ub960\uc740 1%, 2\uc77c \ud655\ub960\uc740 10%, 3\uc77c \ud655\ub960\uc740 30%\ub77c\uace0 \uc608\uce21\ud558\uace0 \uc788\uc2b5\ub2c8\ub2e4. \uadf8\ub7fc, \uc774 \uc608\uce21\uac12\uc640 \uc2e4\uc81c\uac12\uc5d0 \ub300\ud55c \uc624\ucc28\ub294 \uc5b4\ub5bb\uac8c \uacc4\uc0b0\ud560 \uc218 \uc788\uc744\uae4c\uc694? \ubc14\ub85c \uc774 \uc624\ucc28\uac00 \uc190\uc2e4\ud568\uc218\uc758 \uac12\uc774 \ub429\ub2c8\ub2e4.<\/p>\n
\uc190\uc2e4\ud568\uc218\ub294 \ud754\ud788 \ud3c9\uade0\uc81c\uacf1\uc624\ucc28(Mean Squared Error, MSE)\uc640 \uad50\ucc28 \uc5d4\ud2b8\ub85c\ud53c \uc624\ucc28(Cross Entropy Error, CEE)\uac00 \uc0ac\uc6a9\ub429\ub2c8\ub2e4.<\/p>\n
\ud3c9\uade0 \uc81c\uacf1 \uc624\ucc28(Mean Squared Error, MSE)<\/h3>\n
MSE\uc758 \uacf5\uc2dd\uc740 \ub2e4\uc74c\uacfc \uac19\uc2b5\ub2c8\ub2e4.<\/p>\n
<\/p>\n
   <\/span>   <\/span>\"$$E=\frac{1}{2}{\displaystyle\sum_{i=1}^{n} {(y_{i}-t_{i})^{2}}}$$\"<\/p>\n
<\/center><\/p>\n
\uc55e\uc11c \uc5b8\uae09\ud55c \uc2e4\uc81c\uac12 t\uc640 \uc608\uce21\uac12 y\uc5d0 \ub300\ud55c \ud3c9\uade0\uc81c\uacf1\uc624\ucc28\uc758 \uc190\uc2e4\uac12\uc740 \uc544\ub798\uc758 \ud30c\uc774\uc120 \ucf54\ub4dc\ub97c \ud1b5\ud574 \uc5bb\uc744 \uc218 \uc788\uc2b5\ub2c8\ub2e4.<\/p>\n
\r\nimport numpy as np\r\n\r\ndef MSE(y, t):\r\n    return 0.5 * np.sum((y-t)**2)\r\n\r\nt = np.array([0, 0, 0, 0.5, 0.5, 0, 0, 0, 0, 0])\r\ny = np.array([0.01, 0.01, 0.1, 0.3, 0.33, 0.04, 0.02, 0.05, 0.01, 0.1])\r\n\r\nprint(MSE(t,y))\r\n<\/pre>\n
\uc704\uc758 \ucd9c\ub825\uac12\uc73c\ub85c\uc368 \uc190\uc2e4\uac12\uc740 0.04685 \uc785\ub2c8\ub2e4. \uadf8\ub7fc \ub3d9\uc77c\ud55c t\uc5d0 \ub300\ud574 \uc0c1\ub300\uc801\uc73c\ub85c \uc798\ubabb \uc608\uce21\ud55c \uc0c1\ud669\uc758 y\uac12\uc744 \uc544\ub798\ucc98\ub7fc \uc5bb\uc5c8\ub2e4\uace0 \uac00\uc815\ud569\uc2dc\ub2e4.<\/p>\n
\r\ny = [0.3, 0.01, 0.1, 0.01, 0.04, 0.02, 0.05, 0.33, 0.01, 0.1]\r\n<\/pre>\n
\uc704\uc5d0 \ub300\ud55c \uc190\uc2e4\uac12\uc740 0.33685 \uc785\ub2c8\ub2e4. \uc989 \uc190\uc2e4\uac12\uc774 \uc608\uc0c1\ud588\ub358 \uac83\ucc98\ub7fc \uc0c1\ub300\uc801\uc73c\ub85c \ud07d\ub2c8\ub2e4.<\/p>\n
\uad50\ucc28 \uc5d4\ud2b8\ub85c\ud53c \uc624\ucc28(Cross Entropy Error, CEE)<\/h3>\n
CEE\uc758 \uc218\uc2dd\uc740 \ub2e4\uc74c\uacfc \uac19\uc2b5\ub2c8\ub2e4.<\/p>\n
<\/p>\n
   <\/span>   <\/span>\"$$E=-\displaystyle\sum_{i=1}^{n} {t_{i}\log{y_i}}$$\"<\/p>\n
<\/center><\/p>\n
\uc704\uc774 \uc2dd\uc5d0\uc11c log\ub294 \ubc11\uc774 e\uc778 \uc790\uc5f0\ub85c\uadf8\uc785\ub2c8\ub2e4. CEE\uc758 \uc774\ud574\ub97c \uc704\ud574 \uc790\uc5f0\ub85c\uadf8\uc5d0 \ub300\ud55c \uadf8\ub798\ud504\ub97c \uc2dc\uac01\ud654\ud574 \ubcf4\ub294 \ucf54\ub4dc\ub294 \ub2e4\uc74c\uacfc \uac19\uc2b5\ub2c8\ub2e4. <\/p>\n
\r\nimport numpy as np\r\nimport matplotlib.pyplot as plt\r\n \r\nx = np.arange(0, 1, 0.01)\r\ny = np.log(x)\r\n \r\nplt.plot(x, y)\r\nplt.show()\r\n<\/pre>\n
\uadf8\ub798\ud504\ub294 \ub2e4\uc74c\uacfc \uac19\uc2b5\ub2c8\ub2e4.<\/p>\n
\"\"<\/p>\n
\uac00\ub85c\ucd95\uc740 \uc815\ub2f5\uc77c \ud655\ub960\uc774\uace0, y \ucd95\uc740 \uc190\uc2e4\uac12\uc5d0 -1\uc744 \uacf1\ud55c \uac12\uc785\ub2c8\ub2e4. \uac00\ub85c\ucd95\uac12\uc774 1, \uc989 \uc815\ub2f5\uc774 \ud655\ub960\uc774 100%\uc77c\ub54c \uc190\uc2e4\uac12\uc740 0\uc774 \ub418\uace0, \uc815\ub2f5\uc774 \ud655\ub960\uc774 \ub0ae\uc544 \uc9c8\uc218\ub85d \uc190\uc2e4\uac12\uc740 \ubb34\ud55c\ub300\ub85c \ucee4\uc9c0\uac8c \ub429\ub2c8\ub2e4.<\/p>\n
\uc774\uc81c \uc55e\uc11c \uc5b8\uae09\ud55c \uc2e4\uc81c\uac12 t\uc640 \uc608\uce21\uac12 y\uc5d0 \ub300\ud55c \uad50\ucc28 \uc5d4\ud2b8\ub85c\ud53c \uc624\ucc28, CEE\ub97c \uc5bb\ub294 \ud30c\uc774\uc120 \ucf54\ub4dc\ub294 \ub2e4\uc74c\uacfc \uac19\uc2b5\ub2c8\ub2e4.<\/p>\n
\r\nimport numpy as np\r\n\r\ndef CEE(y, t):\r\n    delta = 1e-10\r\n    return -np.sum(t*np.log(y+delta))\r\n\r\nt = np.array([0, 0, 0, 0.5, 0.5, 0, 0, 0, 0, 0])\r\ny0 = [0, 0, 0, 0.5, 0.5, 0, 0, 0, 0, 0]\r\ny1 = [0.01, 0.01, 0.1, 0.3, 0.33, 0.04, 0.02, 0.05, 0.01, 0.1]\r\ny2 = np.array([0.3, 0.01, 0.1, 0.01, 0.04, 0.02, 0.05, 0.33, 0.01, 0.1])\r\n\r\nprint(CEE(t,y0)) # 0.6931471803599453\r\nprint(CEE(t,y1)) # 8.265472039806522\r\nprint(CEE(t,y2)) # 21.21844021456322\r\n<\/pre>\n
\ubcf4\uc2dc\ub294 \uac83\ucc98\ub7fc \uc2e4\uc81c\uac12\uc5d0\uc11c \uc608\uce21\uac12\uc774 \uba40\uc5b4\uc9c8 \uc218\ub85d \uc190\uc2e4\uac12\uc774 \ucee4\uc9c0\ub294 \uac83\uc744 \uc54c \uc218 \uc788\uc2b5\ub2c8\ub2e4.<\/p>\n","protected":false},"excerpt":{"rendered":"
\uc190\uc2e4\ud568\uc218\ub294 \ube44\uc6a9\ud568\uc218(Cost Function)\ub77c\uace0\ub3c4 \ud569\ub2c8\ub2e4. \uc190\uc2e4\uc5d0\ub294 \uadf8\ub9cc\ud07c\uc758 \ube44\uc6a9\uc774 \ubc1c\uc0dd\ud55c\ub2e4\ub294 \uac1c\ub150\uc5d0\uc11c \ub9d0\uc785\ub2c8\ub2e4. \uc190\uc2e4\ud568\uc218\uac00 \uc65c \ud544\uc694\ud55c\uc9c0\ubd80\ud130 \ud30c\uc545\ud558\uae30 \uc704\ud574 \ub2e4\uc74c\uacfc \uac19\uc740 \ub370\uc774\ud130\uac00 \uc788\ub2e4\uace0 \ud569\uc2dc\ub2e4. t = [0, 0, 0, 0.5, 0.5, 0, 0, 0, 0, 0] \ucd1d 10\uac1c \uac12\uc73c\ub85c, \uc5b4\ub5a4 \uc785\ub825\uac12\uc774 0~9\uc911 \uc5b4\ub5a4 \uac12\uc778\uc9c0\ub97c \ub098\ud0c0\ub0b4\ub294 \ud655\ub960\uac12 \uc785\ub2c8\ub2e4. \uccab\ubc88\uc9f8 \uac12\uc774 0\uc77c\ub54c\uc758 \ud655\ub960\uc774\uace0, \ub450\ubc88\uc9f8\uac00 1\uc77c\ub54c\uc758 \ud655\ub960\uc785\ub2c8\ub2e4. \uc989, \uc704\uc758 \uac12\uc740 3\uc77c\ub54c\uc640 4\uc77c\ub54c\uc758 … <\/p>\n
\ub354 \ubcf4\uae30 “\uc190\uc2e4\ud568\uc218(Loss Function)”<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[132],"tags":[],"class_list":["post-7631","post","type-post","status-publish","format-standard","hentry","category-deep-machine-learning"],"_links":{"self":[{"href":"http:\/\/www.gisdeveloper.co.kr\/index.php?rest_route=\/wp\/v2\/posts\/7631","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.gisdeveloper.co.kr\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.gisdeveloper.co.kr\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.gisdeveloper.co.kr\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.gisdeveloper.co.kr\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=7631"}],"version-history":[{"count":10,"href":"http:\/\/www.gisdeveloper.co.kr\/index.php?rest_route=\/wp\/v2\/posts\/7631\/revisions"}],"predecessor-version":[{"id":9394,"href":"http:\/\/www.gisdeveloper.co.kr\/index.php?rest_route=\/wp\/v2\/posts\/7631\/revisions\/9394"}],"wp:attachment":[{"href":"http:\/\/www.gisdeveloper.co.kr\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=7631"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.gisdeveloper.co.kr\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=7631"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.gisdeveloper.co.kr\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=7631"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}