<div class="field field-name-field-news-column-category field-type-taxonomy-term-reference field-label-hidden"><div class="field-items"><div class="field-item even"><a href="/tags/%E6%96%B0%E8%81%9E">新聞</a></div></div></div><div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even"> <p>人工智慧現在也可以幫人類探索宇宙，由柏克萊大學、日本卡弗里數物連攜宇宙研究機構、英屬哥倫比亞大學以及卡內基美隆大學研究員組成的研究團隊，開發了<a href="https://www.simonsfoundation.org/2019/06/26/ai-universe-simulation/"><span style="color: rgb(26, 26, 26); font-family: "Univers Next W01", Helvetica, Ariel, sans-serif; font-size: 15px; font-variant-ligatures: common-ligatures;">D</span><sup style="box-sizing: inherit; touch-action: inherit; margin: 0px; padding: 0px; border: 0px; background-image: initial; background-position: 0px 0px; background-size: initial; background-repeat: initial; background-attachment: initial; background-origin: initial; background-clip: initial; font-variant-ligatures: common-ligatures; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: 15px; font-family: "Univers Next W01", Helvetica, Ariel, sans-serif; font-size: 0.6em; outline: 0px; display: inline-block; color: rgb(26, 26, 26);">3</sup><span style="color: rgb(26, 26, 26); font-family: "Univers Next W01", Helvetica, Ariel, sans-serif; font-size: 15px; font-variant-ligatures: common-ligatures;">M</span>（Deep Density Displacement Model）模型</a>，這個模型能夠快速且精確地模擬宇宙的樣貌，以及在改變特定參數後的樣子。</p>
<p>這是天體物理學家第一次使用人工智慧技術，對宇宙進行3D模擬，研究人員表示，他們所開發的<span style="color: rgb(26, 26, 26); font-family: "Univers Next W01", Helvetica, Ariel, sans-serif; font-size: 15px; font-variant-ligatures: common-ligatures;">D</span><sup style="box-sizing: inherit; touch-action: inherit; margin: 0px; padding: 0px; border: 0px; background-image: initial; background-position: 0px 0px; background-size: initial; background-repeat: initial; background-attachment: initial; background-origin: initial; background-clip: initial; font-variant-ligatures: common-ligatures; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: 15px; font-family: "Univers Next W01", Helvetica, Ariel, sans-serif; font-size: 0.6em; outline: 0px; display: inline-block; color: rgb(26, 26, 26);">3</sup><span style="color: rgb(26, 26, 26); font-family: "Univers Next W01", Helvetica, Ariel, sans-serif; font-size: 15px; font-variant-ligatures: common-ligatures;">M</span>模型，能夠以參數調整，快速且精確地模擬宇宙的外觀，回答像是宇宙中有多少暗物質（Dark Matter）存在等問題，也可以讓科學家知道，宇宙在各種情境條件下演變的狀況。由於每個情境條件都需要進行數千次的模擬，花費大量的計算時間，而這也使得開發出高速且精確的運算模型，成為現代天體物理學重要的目標之一。</p>
<p>天體物理學家關注重力，因為重力是形塑宇宙最重要的力量，但是精確的宇宙模擬，需要計算宇宙中數十億個粒子，受重力長時間影響的移動狀況，一次需要花費約300個模擬計算小時，雖然有較快速的模擬方法，可以將模擬時間壓縮至2分鐘，但是卻會讓精準度大幅下降。</p>
<p>在美國國家科學院院刊發表的<span style="color: rgb(26, 26, 26); font-family: "Univers Next W01", Helvetica, Ariel, sans-serif; font-size: 15px; font-variant-ligatures: common-ligatures;">D</span><sup style="box-sizing: inherit; touch-action: inherit; margin: 0px; padding: 0px; border: 0px; background-image: initial; background-position: 0px 0px; background-size: initial; background-repeat: initial; background-attachment: initial; background-origin: initial; background-clip: initial; font-variant-ligatures: common-ligatures; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: 15px; font-family: "Univers Next W01", Helvetica, Ariel, sans-serif; font-size: 0.6em; outline: 0px; display: inline-block; color: rgb(26, 26, 26);">3</sup><span style="color: rgb(26, 26, 26); font-family: "Univers Next W01", Helvetica, Ariel, sans-serif; font-size: 15px; font-variant-ligatures: common-ligatures;">M</span>，能快速地模擬重力如何形塑宇宙，研究團隊使用PyTorch深度學習框架和GPU，以8,000種不同的模擬訓練資料，進行深度神經網路訓練，這些模擬資料來自另一個高精準度模型所產生的結果。</p>
<p><span style="color: rgb(26, 26, 26); font-family: "Univers Next W01", Helvetica, Ariel, sans-serif; font-size: 15px; font-variant-ligatures: common-ligatures;">D</span><sup style="box-sizing: inherit; touch-action: inherit; margin: 0px; padding: 0px; border: 0px; background-image: initial; background-position: 0px 0px; background-size: initial; background-repeat: initial; background-attachment: initial; background-origin: initial; background-clip: initial; font-variant-ligatures: common-ligatures; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: 15px; font-family: "Univers Next W01", Helvetica, Ariel, sans-serif; font-size: 0.6em; outline: 0px; display: inline-block; color: rgb(26, 26, 26);">3</sup><span style="color: rgb(26, 26, 26); font-family: "Univers Next W01", Helvetica, Ariel, sans-serif; font-size: 15px; font-variant-ligatures: common-ligatures;">M</span>模型訓練完成之後，研究人員對6億光年的箱型宇宙進行模擬，並把模擬結果與其他需要數百小時運算的高精準度模型，以及數分鐘的高速模型進行比較。<span style="color: rgb(26, 26, 26); font-family: "Univers Next W01", Helvetica, Ariel, sans-serif; font-size: 15px; font-variant-ligatures: common-ligatures;">D</span><sup style="box-sizing: inherit; touch-action: inherit; margin: 0px; padding: 0px; border: 0px; background-image: initial; background-position: 0px 0px; background-size: initial; background-repeat: initial; background-attachment: initial; background-origin: initial; background-clip: initial; font-variant-ligatures: common-ligatures; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: 15px; font-family: "Univers Next W01", Helvetica, Ariel, sans-serif; font-size: 0.6em; outline: 0px; display: inline-block; color: rgb(26, 26, 26);">3</sup><span style="color: rgb(26, 26, 26); font-family: "Univers Next W01", Helvetica, Ariel, sans-serif; font-size: 15px; font-variant-ligatures: common-ligatures;">M</span>模型計算時間僅花費30毫秒，產生的結果相對誤差只有高精確度模型的2.8％，也就是說在省下大量運算時間的同時，還能保有一定水準的精確度。</p>
<p>而<span style="color: rgb(26, 26, 26); font-family: "Univers Next W01", Helvetica, Ariel, sans-serif; font-size: 15px; font-variant-ligatures: common-ligatures;">D</span><sup style="box-sizing: inherit; touch-action: inherit; margin: 0px; padding: 0px; border: 0px; background-image: initial; background-position: 0px 0px; background-size: initial; background-repeat: initial; background-attachment: initial; background-origin: initial; background-clip: initial; font-variant-ligatures: common-ligatures; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: 15px; font-family: "Univers Next W01", Helvetica, Ariel, sans-serif; font-size: 0.6em; outline: 0px; display: inline-block; color: rgb(26, 26, 26);">3</sup><span style="color: rgb(26, 26, 26); font-family: "Univers Next W01", Helvetica, Ariel, sans-serif; font-size: 15px; font-variant-ligatures: common-ligatures;">M</span>模型跟高速模型相比更不用說，高速模型花了更多的時間，得到的結果還存在約10％的相對誤差。研究團隊指出，<span style="color: rgb(26, 26, 26); font-family: "Univers Next W01", Helvetica, Ariel, sans-serif; font-size: 15px; font-variant-ligatures: common-ligatures;">D</span><sup style="box-sizing: inherit; touch-action: inherit; margin: 0px; padding: 0px; border: 0px; background-image: initial; background-position: 0px 0px; background-size: initial; background-repeat: initial; background-attachment: initial; background-origin: initial; background-clip: initial; font-variant-ligatures: common-ligatures; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: 15px; font-family: "Univers Next W01", Helvetica, Ariel, sans-serif; font-size: 0.6em; outline: 0px; display: inline-block; color: rgb(26, 26, 26);">3</sup><span style="color: rgb(26, 26, 26); font-family: "Univers Next W01", Helvetica, Ariel, sans-serif; font-size: 15px; font-variant-ligatures: common-ligatures;">M</span>模型的另一個特點是，模擬在訓練資料中所未曾出現的參數，結果也相同精準，而這使得該模型成為富彈性的工具，可用於模擬訓練資料未覆蓋的參數空間。</p>
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