• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 6
  • 6
  • Tagged with
  • 6
  • 6
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • 3
  • 3
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

各險種經驗死亡率之分析與期保費高低估之探討 / The analysis of empirical mortality rates for different insurance products and the estimations of insurance premiums

呂政治 Unknown Date (has links)
隨著台灣經濟的大幅提升與保險的觀念在國內越來越盛行,許多的人都會選擇去投保,本研究採用的資料是從保險事業發展中心所獲得,其收集台灣各個保險公司所銷售的保單,包含定期險、生死合險和終身壽險的資料。我們藉由此資料來分析具有何種特質的人會去購買何種保單,哪些因素會造成死亡率之間的差異。近些年來,台灣的生活水準和醫療水平有顯著的進步,台灣人口的死亡率也因此大幅地下降,男女間的平均餘命也隨之增加,台灣逐步地邁向高齡化社會。但隨著死亡率的改善,保險公司之前所銷售的較長年期的保險商品,有可能會造成保險公司低估或高估其保費,使公司未來的現金流量不穩定。而且以前公司通常是使用生命表的死亡率為基礎,但這樣並不能真正反映有保險人口的死亡機率,因此,我們將使用實際投保的資料,透過Whittaker修勻和Gompertz法則,計算其死亡率,並利用Lee -Carter模型去對未來的死亡率做預測,探討死亡率的下降,會對保險公司造成何種衝擊與其影響到底會有多大。
2

曲線配適於磁振造影之應用

簡仲徽 Unknown Date (has links)
在醫學領域中,磁振造影(Magnetic Resonance Imaging, MRI)因為具有良好的空間解析度及對比度,且不會對人體產生任何輻射性或侵入性的傷害,所以在疾病診斷中為經常被醫師們使用的輔助工具。其中利用磁振造影測量患者腦部血流情形所攝得之對比劑濃度與時間關係曲線圖,更是醫學界在對付腦血管病變(Brain Lesion)時的診斷利器。然而截至目前為止,我們尚未有一個較正確且快速的方法可以用來配適其對比劑濃度與時間關係曲線中的參數。所以在本論文中,我們嘗試以統計上的觀點,利用幾種不同的配適方法,找出與原始觀察值最為接近之估計值。 在本研究中使用的配適方法有—「迴歸分析法」、「Whittaker修勻法」、「非線性函數參數修勻法」及「核修勻法(Kernel Graduation)」。 本論文將以往醫學界慣用的「乘方性誤差項」改變為「加成性誤差項」,再以不同的誤差項,利用電腦模擬出各組假資料(Pseudo Data)後,以上述的四種方式對原始觀察值進行參數配適與函數估計。綜合模擬資料與真實資料所配適的比較結果,我們認為在幾種方法中,最穩健(Robust)的配適法是「Whittaker修勻法」。而在本論文中進行配適的真實資料,應該具有較大的誤差項,才導致非線性函數參數修勻法不能得出很好的估計值。 / With greater resolution, higher contrast and no radiative hurt to human body, Magnetic Resonance Imaging (MRI) is widely used by doctors in diagnosing diseases. The concentration of the contrast agent v.s. time curves which generated by MRI for cerebral blood flowing is very useful to doctors when giving treatments to brain lesion. However, we still have no precise and quick solution for fitting the curve of the concentration of the contrast agent vs. time. Therefore, this essay tries to use some different statistical fitting methods to find the closest estimates to the crude observations. We will use four different fitting methods here—"Regression Analysis", "Whittaker Graduation", "Nonlinear Function Parametric Graduation", "Kernel Graduation". This essaywill change the "multiple error term" which was usually used in the medical field to "additive error term". After using different sizes of error terms to generate pseudo data by computer simulation, we fit the parameters and estimate the values of the function to the crude data we've created with the four fitting methods mentioned above. Comparing the fitting result of the simulation data and the real data, we think the most robust fitting method is " Whittaker Graduation". The real data we have fitted in this essay may contain a greater error term, it would make " Nonlinear Function Parametric Graduation" get inadequate fitting values.
3

修勻與小區域人口之研究 / A Study of smoothing methods for small area population

金碩, Jin, Shuoh Unknown Date (has links)
由於誤差與人口數成反比,資料多寡影響統計分析的穩定性及可靠性,因此常用於推估大區域人口的方法,往往無法直接套用至縣市及其以下層級,尤其當小區域內部地理、社會或經濟的異質性偏高時,人口推估將更為棘手。本文以兩個面向對臺灣小區域人口進行探討:其一、臺灣人口結構漸趨老化,勢必牽動政府政策與資源分配,且臺灣各縣市的人口老化速度不一,有必要針對各地特性發展適當的小區域人口推估方法;其二、因為壽命延長,全球皆面臨長壽風險(Longevity Risk)的挑戰,包括政府退休金制度規劃、壽險保費釐定等,由於臺灣各地死亡率變化不盡相同,發展小區域死亡率模型也是迫切課題。 小區域推估面臨的問題大致可歸納為四個方向:「資料品質」、「地區人數」、「資料年數」與「推估年數」,資料品質有賴資料庫與制度的建立,關於後三個問題,本文引進修勻(Smoothing, Graduation)等方法來提高小區域推估及小區域死亡模型的穩定性。人口推估方面結合修勻與區塊拔靴法(Block Bootstrap),死亡率模型的建構則將修勻加入Lee-Carter與Age-Period-Cohort模型。由於小區域人口數較少,本文透過標準死亡比(Standard Mortality Ratio)及大區域與小區域間的連貫(Coherence),將大區域的訊息加入小區域,降低因為地區人數較少引起的震盪。 小區域推估通常可用的資料時間較短,未來推估結果的震盪也較大,本文針對需要過去幾年資料,以及未來可推估年數等因素進行研究,希冀結果可提供臺灣各地方政府的推估參考。研究發現,參考大區域訊息有穩定推估的效果,修勻有助於降低推估誤差;另外,在小區域推估中,如有過去十五年資料可獲得較可靠的推估結果,而未來推估年數盡量不超過二十年,若地區人數過少則建議合併其他區域增加資料量後再行推估;先經過修勻而得出的死亡率模型,其效果和較為複雜的連貫模型修正相當。 / The population size plays a very important role in statistical estimation, and it is difficult to derive a reliable estimation for small areas. The estimation is even more difficult if the geographic and social attributes within the small areas vary widely. However, although the population aging and longevity risk are common phenomenon in the world, the problem is not the same for different countries. The aim of this study is to explore the population projection and mortality models for small areas, with the consideration of the small area’s distinguishing characteristic. The difficulties for small area population projection can be attributed into four directions: data quality, population size, number of base years, and projection horizon. The data quality is beyond the discussion of this study and the main focus shall be laid on the other three issues. The smoothing methods and coherent models will be applied to improve the stability and accuracy of small area estimation. In the study, the block bootstrap and the smoothing methods are combined to project the population to the small areas in Taiwan. Besides, the Lee-Cater and the age-period-cohort model are extended by the smoothing and coherent methods. We found that the smoothing methods can reduce the fluctuation of estimation and projection in general, and the improvement is especially noticeable for areas with smaller population sizes. To obtain a reliable population projection for small areas, we suggest using at least fifteen-year of historical data for projection and a projection horizon not more than twenty years. Also, for developing mortality models for small areas, we found that the smoothing methods have similar effects than those methods using more complicated models, such as the coherent models.
4

小區域生育率與人口推計研究 / Small Population Projections:Modeling and Evaluation

曹郁欣, Eunice Y. Tsao Unknown Date (has links)
由於許多國家死亡率下降快速、壽命延長幅度超乎預期,加上生育率持續低於替代水準,人口老化現象愈發明顯,近年來個人生涯規劃及政府施政,都格外強調退休後經濟生活及老年相關社會資源分配的比重。以臺灣為例,行政院經濟建設委員會 (簡稱經建會) 從1990年代開始,每兩年公布一次未來的人口推估,但過去十年來經建會屢次修正歷年的推估假設,以因應生育率及死亡率變化快速,適時提醒臺灣日益加速的人口老化。正因為人口推估可能受到人口數、社會變遷、資料品質等因素,影響統計分析的可靠性,常用於國家層級的推估方法,往往無法直接套用至縣市及其以下的層級 (即小區域),使得小區域人口推估較為棘手,需要更加謹慎面對。 本文延續王信忠等人 (2012) 的研究,以小區域人口推估為目標,著重在生育率推估研究,結合隨機模型與修勻方法,尋找適合臺灣縣市層級的小區域人口推估方法。本文考量的隨機模型計有區塊拔靴法 (Block Bootstrap) 和 Lee-Carter 模型 (Lee and Carter 1992),以預測未來的生育率和死亡率,並套用年輪組成推計法 (或稱為人口要素合成法;Cohort Component Method) 及修勻 (Graduation) 方法,探討這些方法與人口規模之間的關係,評估用於小區域人口推估之可行性。 本文首先以電腦模擬,探討生育率的推估,討論是否可直接推估總生育率,類似增加樣本數的概念,取代各縣市的年齡別生育率,以取得較為穩定的推估。根據模擬結果,發現人口規模對出生數的推估沒有明顯的關係,只要使用總生育率、再結合區塊拔靴法,就足以提供穩定的推估結果。實證研究方面,以臺灣縣市層級的人口及其年齡結構 (例如:0-14歲、15-64歲、65歲以上) 為驗證對象,發現分析結果也與電腦模擬相似,發現以區塊拔靴法推估臺灣各縣市的總生育率、年齡組死亡率,其推估精確度不因人口規模而打折扣,顯示以區塊拔靴法推估總生育率、年齡組死亡率,可用於推估臺灣小地區的未來人口。 / Due to the rapid mortality reduction, prolonging human longevity is a common phenomenon and longevity risk receives more attention in 21st century. Many developed countries encounter many problems brought up by prolonging life, such as poor community infrastructure and insufficient financial pension funds for the elderly. Population Projection thus becomes essential in government planning in dealing with the population aging. However, rapid changes in mortality and fertility make the projection very tricky. It would be even more difficult to project areas with fewer populations (i.e., small areas) since it takes extra efforts to deal with the larger fluctuations in small population. The objective of the study is to construct a standard operating procedure (SOP) for small population projection. Unlike the previous study, e.g., Wang et al. (2012), we will take both the fertility and mortality into account (but set migration aside for simplicity). First, for the fertility projection, we evaluate if total fertility rates (TFR) are more appropriate than the age-specific fertility rates for small population. Also, we compare two fertility projection methods: Lee-Carter model and block bootstrap, and check which shows better results. Based on the computer simulation, we found that TFR performs better and the block bootstrap method is more sensitive to rapid fertility changes. As for mortality rate projection, we also recommend the standard operating procedure by Wang et al. (2012). However, the smoothing methods have limited impacts on mortality projection and can be ignored. In addition to simulation, we also apply the SOP for projecting the small population to Taiwan counties and it achieves satisfactory results. However, due to the availability of data, our method can only be used for short-term projection (at most 30 years) and these results might not apply to long-term projection. Also, similar to the previous work, the fertility rates have the larger impact on small population projection, although we think that the migration has large impact as well. In this study, only the stochastic projection is considered and we shall consider including expert opinions as the future study.
5

小區域死亡率模型與生命表編算 / A Study of Mortality Models and Life Table Construction of Small Areas

鍾陳泰, Chung, Chen Tai Unknown Date (has links)
臺灣各縣市人口結構差異明顯,各縣市的人口出生、老化程度都不盡相同,而且在醫療分配及社會資源的使用也有很大的差異,因此各縣市應因應各地特性發展不同的小區域人口推估方法。由於樣本數與變異數成反比,人數較少者的死亡率(像是高齡人口)通常震盪較大,藉由適當的修勻(Graduation)調整,通常可降低年齡層間的死亡率震盪。然而,當縣市層級的人數太少時,只依賴修勻往往不足,多半會再參考人口較多的大母體之死亡率。例如:傳統的的貝氏修勻,使用Lee-Carter之類的參數死亡模型(Lee and Carter, 1992),或是透過小區域及大母體的死亡率比值(王信忠, 2012)。然而過去研究較少全面性的比較這些方法,尤其是用於人數較少(如:十萬人)的地區。 本文以探討小區域生命表及死亡率推估為目標,著眼於人數不多於五萬人,尋求較為適合臺灣及類似國家的死亡率編算方法。由於修勻或貝氏等方法可視為增加樣本數,本文將擴大樣本分為四種方式:「同地同時」、「同地異時」、「異地同時」、「異地異時」,亦即將死亡資料的整併分成是否限定於小區域,以及是否可擴及其他年度。本文藉由電腦模擬測試,提供在各種限制之下,最合適小區域生命表建構的準則。其中,本文假設大、小區域的死亡率間存有三種情境的關係:定值、遞增、V字型,藉由調整大小區域死亡率比值間的幅度,探討大母體及小區域間的差異對實務使用的影響。研究發現,Partial SMR方法是一個值得參考的方法,當大小區域死亡率類型接近時的效果不錯,甚至可用於人數小於一萬人,但若死亡率類型差異過大,修勻方法會有限制,使用時需格外謹慎。 / The population structure, life expectancy (and age-specific mortality rates), and the speed of population aging vary a lot in different county of Taiwan. Each county has its own policy planning according to the needs. However, the county level population is usually not enough to provide stable estimates, such as of the life expectancies and mortality rates at the county level. Thus, certain graduation methods are applied to stabilize these estimates. However, only a few studies focus on comparing different types of graduation methods, including traditional graduation methods, Bayesian methods, and parametric mortality models. In this study, we separate the graduation methods into four types, according to if using only the small area data and if one year or multiple years of data are used, and explore which methods are appropriate to the areas with population fewer than 100,000. We use computer simulation to evaluate the graduation methods. We found that the Standard Mortality Ratio is promising when the mortality profiles of small and large populations are similar, and it is a feasible solution even for the areas with population fewer than 10,000. However, if the mortality profiles differ significantly, all graduation methods need to be applied with care.
6

小區域死亡率模型的探討 / A Study of Small Area Mortality Models

林志軒 Unknown Date (has links)
壽命延長及生育率下降使得人口老化日益明顯,成為全球多數國家在21世紀必須面對的議題,由於各區域人口老化的速度不同,必須根據各地特性而調整因應對策。其中研究死亡率變化為面對人口老化的必備課題,尤其是高齡族群的死亡率,這也是近年高齡死亡模型廣受重視的主因之一。因為樣本數與變異數成反比,人口較少的區域或是高齡人口,死亡率的觀察值通常會有較大震盪,為了降低震盪多半會經過修勻,以取得較為穩定的死亡率推估值(王信忠等人,2012)。此外,Li and Lee (2005)的Coherent Lee-Carter模型也是另一種可行方法,透過參考大區域的資訊降低小區域的估計誤差。 本文探討結合上述修勻、死亡率模型的可能,希冀能綜合兩者的優點,提高小區域死亡率推估的精確性。因為Coherent Lee-Carter模型的想法類似增加小區域的人數(加入大區域的人數),本文探討人口數與Lee-Carter模型參數估計值的關係,再以修勻調整大小區域的差異,透過電腦模擬及資料分析,驗證本文提出方法是否有效。其中,仿造王信忠等人的作法,假設小區域與大區域死亡率間的七種可能情境,以平均絕對百分誤差(Mean Absolute Percentage Error)為衡量標準,找出調整修勻、相關模型的方法。另外,本文也以臺灣縣市為研究區域,驗證本文方法的估計結果。研究發現適當地使用修勻方法,可降低小區域的死亡率估計值,其效果優於Coherent Lee-Carter模型。

Page generated in 0.0144 seconds