An Empirical Study of Simulation and Stochastic Methods on the Population Projections

人口推估(Population Projection)涉及國家的政策及規劃，精確的結果可協助國家適時制訂政策，提高國民福祉。臺灣現在使用的方法為人口變動要素合成法(The Cohort Component Method)，可算是情境推估(Scenario Forecast)的一種，其起源可追溯至1920年代(Whelpton, 1928)，參酌專家意見之後，使用高、中、低三種推計來描述其變動範圍。除了情境推估外，近年在人口變動要素合成方法上發展出的新方法大致可以分成三種：一為隨機推估(Stochastic Forecast Method)、一為模擬情境(Random Scenario Method)、一為推估誤差(ex post Method)，美國及聯合國已經不單單依賴專家提供的傳統高、中、低推計，轉而使用這些新的推估方法。 由於近年來生育率快速降低、平均餘命延長以及外籍新娘增多等因素，大為提高人口推估的難度，因此本文將機率的概念併入人口推估中，以預測區間（Prediction Interval）來捕捉人口各項特性的可能變動範圍。除了回顧幾種在人口變動要素合成法中發展出的隨機推估方法及合併專家意見的方針外，也使用區塊拔靴法(Block Bootstrap)電腦模擬，進行臺灣、美國、日本、法國四個國家的人口推估。另外，本文也採用以Stoto(1983)提出的預測誤差估計，評估區塊拔靴法和人力規劃處推估結果之異同，以提供使用專家意見與隨機方法的參考。最後則是比較臺灣以北中南東小區域推估和臺灣整體的推估結果，並合併專家意見進行臺灣地區人口推估

JUNO Sensitivity on Proton Decay p→νˉK+p\to \bar\nu K^+ Searches

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this paper, the potential on searching for proton decay in $p\to \bar\nu K^+$ mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits to suppress the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar\nu K^+$ is 36.9% with a background level of 0.2 events after 10 years of data taking. The estimated sensitivity based on 200 kton-years exposure is $9.6 \times 10^{33}$ years, competitive with the current best limits on the proton lifetime in this channel

JUNO sensitivity on proton decay p → ν K + searches*

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this study, the potential of searching for proton decay in the $p\to \bar{\nu} K^+$ mode with JUNO is investigated. The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits suppression of the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar{\nu} K^+$ is 36.9% ± 4.9% with a background level of $0.2\pm 0.05({\rm syst})\pm$$0.2({\rm stat})$ events after 10 years of data collection. The estimated sensitivity based on 200 kton-years of exposure is $9.6 \times 10^{33}$ years, which is competitive with the current best limits on the proton lifetime in this channel and complements the use of different detection technologies