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$h$ 变成类别分数 $a=Wh+b$。换成“哪一只杯子在左边”时，原分类头的类别名单往往无用，但前面识别轮廓、纹理和部件的计算可能仍有用。这就是移除原头、保留编码器的起点。它提出了一个可检验的假设：**旧任务塑造的中间计算，能降低新任务学习的困难。**","sha256":"8787e6222b812c908f9fb8b9ee10c780670ad4f78049032105346bdc08842346","chapter":{"id":"I","title":"学习信号与表示"},"unit":{"id":"i-reuse-and-targets","title":"训练留下什么，训练答案又从哪里来？"},"page":{"id":"reading-opening","title":"训练留下参数；一次输入才产生表示","number":1},"sectionTitle":"训练留下参数；一次输入才产生表示","currentQuestion":"训练留下参数；一次输入才产生表示","sourceSlides":[],"knowledgeBlock":null,"formulas":[{"latex":"h","definitionContext":"训练留下参数；一次输入才产生表示"},{"latex":"a=Wh+b","definitionContext":"训练留下参数；一次输入才产生表示"}],"previousBlock":"b-2f721c0e3edaaa69ba34fb93","nextBlock":"b-17b62e6be77751437d992ea6","prerequisites":[{"id":"b-a4d56e6f8d94d8f02d1d791b","url":"#b-a4d56e6f8d94d8f02d1d791b","role":"section-title"},{"id":"b-810d2767fac8b994c4d087b9","url":"#b-810d2767fac8b994c4d087b9","role":"problem-context"}],"relatedBlocks":[{"id":"b-6ccebf8917467cd397623cb8","url":"#b-6ccebf8917467cd397623cb8","relation":"figure-and-explanation"}]},{"id":"b-17b62e6be77751437d992ea6","type":"p","scope":"representation-after-training","url":"https://codingai-lec03.pages.dev/course/blocks/representation-after-training.html#b-17b62e6be77751437d992ea6","content":"看当前图时，先指向“图像→表示”，再指向“表示→类别”。本讲第一部分改变前一段怎样学习，第二部分改变后一段要交付什么；不要求把所有问题塞进同一个输出向量。","sha256":"8192daa71ce48b219345b5a9c01e4c9ab2830a269b9191c681a73780bdb9010f","chapter":{"id":"I","title":"学习信号与表示"},"unit":{"id":"i-reuse-and-targets","title":"训练留下什么，训练答案又从哪里来？"},"page":{"id":"reading-opening","title":"训练留下参数；一次输入才产生表示","number":1},"sectionTitle":"训练留下参数；一次输入才产生表示","currentQuestion":"训练留下参数；一次输入才产生表示","sourceSlides":[],"knowledgeBlock":null,"formulas":[],"previousBlock":"b-5fffb3d19b8d3ecc21b772ba","nextBlock":"b-6ccebf8917467cd397623cb8","prerequisites":[{"id":"b-a4d56e6f8d94d8f02d1d791b","url":"#b-a4d56e6f8d94d8f02d1d791b","role":"section-title"},{"id":"b-810d2767fac8b994c4d087b9","url":"#b-810d2767fac8b994c4d087b9","role":"problem-context"}],"relatedBlocks":[{"id":"b-6ccebf8917467cd397623cb8","url":"#b-6ccebf8917467cd397623cb8","relation":"figure-and-explanation"}]},{"id":"b-6ccebf8917467cd397623cb8","type":"figure","scope":"representation-after-training","url":"https://codingai-lec03.pages.dev/course/blocks/representation-after-training.html#b-6ccebf8917467cd397623cb8","content":"图内标签与数值：P01 学习表示机制图，状态 1；同一场景；是什么？；杯子 · 书；学习信号；区域与像素；语言与任务\n\n参数是处理规则，表示是规则对当前图像的响应。 查看对应图解状态\n\n- 同一场景\n- 是什么？\n- 杯子 · 书\n- 学习信号\n- 区域与像素\n- 语言与任务参数是处理规则，表示是规则对当前图像的响应。 [查看对应图解状态](/#/l3-r2-p01/0)[查看完整图解](/#/l3-r2-p01/0)","sha256":"843ff5f58a4346b78cebddad033b2a9ad33726953dde441418b914a3bedd3d34","chapter":{"id":"I","title":"学习信号与表示"},"unit":{"id":"i-reuse-and-targets","title":"训练留下什么，训练答案又从哪里来？"},"page":{"id":"reading-opening","title":"训练留下参数；一次输入才产生表示","number":1},"sectionTitle":"训练留下参数；一次输入才产生表示","currentQuestion":"训练留下参数；一次输入才产生表示","sourceSlides":[],"knowledgeBlock":null,"formulas":[],"figure":{"caption":"参数是处理规则，表示是规则对当前图像的响应。 查看对应图解状态","labels":["同一场景","是什么？","杯子 · 书","学习信号","区域与像素","语言与任务"],"description":"参数是处理规则，表示是规则对当前图像的响应。 查看对应图解状态同一场景是什么？杯子 · 书学习信号区域与像素语言与任务","evidenceIdentity":"参数是处理规则，表示是规则对当前图像的响应。 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继续阅读与实验","sha256":"2b9ccef7e1220e2250cceff1abd8bdd736b42f8da5a223f26b029f44b962e807","chapter":{"id":"I","title":"学习信号与表示"},"unit":{"id":"i-reuse-and-targets","title":"训练留下什么，训练答案又从哪里来？"},"page":{"id":"reading-opening","title":"训练留下参数；一次输入才产生表示","number":1},"sectionTitle":"训练留下参数；一次输入才产生表示","currentQuestion":"训练留下参数；一次输入才产生表示","sourceSlides":[],"knowledgeBlock":null,"formulas":[],"previousBlock":"b-6ccebf8917467cd397623cb8","nextBlock":null,"prerequisites":[{"id":"b-a4d56e6f8d94d8f02d1d791b","url":"#b-a4d56e6f8d94d8f02d1d791b","role":"section-title"},{"id":"b-810d2767fac8b994c4d087b9","url":"#b-810d2767fac8b994c4d087b9","role":"problem-context"}],"relatedBlocks":[{"id":"b-6ccebf8917467cd397623cb8","url":"#b-6ccebf8917467cd397623cb8","relation":"figure-and-explanation"}]}]}