• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 166
  • 140
  • 26
  • Tagged with
  • 166
  • 166
  • 79
  • 62
  • 60
  • 57
  • 54
  • 52
  • 47
  • 45
  • 41
  • 41
  • 37
  • 33
  • 32
  • 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.
91

正值隨機變數動差理論之探討

林春龍, Lin, Chun-Long Unknown Date (has links)
本論文旨在討論正值隨幾變數動差及其有關的問題。計分六章,每章三至五節,約三 萬字。第一章為緒論。主要在說明研究動機、目的、方法、及範圍。第二章則說明動 差的構成及其特性,且了解群體動差與樣本動差彼此的關係,進而研究在抽樣調查中 的應用。第三章以討論母函數為主,並不接受母函數只有一類的說法,亦即把母函數 分成兩大類:算術型與調和型的母函數,進而闡釋後者在統計學中可能發展的趨向及 其重要性。另外,結於新母函數的可能產生也作了剖切的說明。第四章說明母函數與 動差的關係,並說明了用母函數求各種正負動差的各種可能方法。第五章則說明群體 動差的不等式關係,多變值群體動差的不等式關係及相對動差的分布問題。第六章為 結論對於整個內容作一整個連繫。
92

隨機利率下選擇權定價與避險

吳庭斌 Unknown Date (has links)
本論文推導了四種隨機利率下匯率連動選擇權評價模型及其避險比率,其依序為匯率連動選擇權、匯率連動交換選擇權、後定選擇權與匯率連動遠期契約,並比較上述選擇權在隨機利率下與固定利率下評價模型與避險比率之差異。在固定利率下的評價公式與避險比率,其折現因子為固定利率,然而在隨機利率下的評價公式,是以零息債券折現,因此能反映未來利率波動。若發行券商預期未來利率有大幅波動或選擇權的到期日較長時,應使用隨機利率下的評價公式,方能得到較合理的價格。
93

考量保險業加入國外投資之最適組合 / Incorporating Foreign Equities in Optimal Portfolio Selection for Insurers and Investors with Significant Background Risks

洪莉娟, Li-Chuan Hung Unknown Date (has links)
本研究探討面臨顯著背景風險(諸如核保等風險)金融機構之投資策略,考量加入國外投資風險下,該金融機構如何決定最適動態資產配置策略,為充分反映市場風險、匯率風險及核保風險,本研究以隨機方程式描述資產價值及核保經驗之變動,並以假想之人壽保險公司作為討論對象,預估未來現金流量並建構公司財務資訊相關之隨機模型,給定最低資本限制下,於指定投資期限內達到全期淨值(盈餘)最佳效用值為目標。本文依照給定之背景風險建構隨機控制模型,利用動態規劃法求出最適資產配置。結果顯示最適投資組合將由三項要素組成:1.極小化盈餘變化之變異數之部位;2.類似於短期投資組合策略之避險部位;以及3.用以規避背景風險之避險部位。因為模型複雜性之限制,以逼近馬可夫理論之數值方法計算最適投資策略。 / This paper analyzes the optimal asset allocation for insurers and investors who are required to cope with significant background risks due to underwriting uncertainties and interest rate risks among a set of stochastic investment opportunities. In order to hedge properly the country risks due to local volatile financial market, the foreign investment opportunities are included in the optimal portfolio decision. In this study, detailed formulation using the projected cash flows of a hypothetical life insurance company and its related stochastic phenomena are constructed. The insurers are assumed to maximize the expected discounted utility of their surplus over the investment horizon under the minimal capital requirement. Our problem is formulated as a stochastic control framework. According to the optimal solution, the optimal portfolio can be characterized by three components: a hedging component minimizing the variance of the change in surplus, a hedging component familiar to myopic portfolio rule, and a risk hedging component against the background risks. Since the explicit solutions cannot be achieved due to model complexity, the Markov chain approximation methods are employed to obtain the optimal control solutions in our numerical illustration.
94

隨機利率下,跨通貨投資組合選擇權之定價與避險策略 / Pricing and Hedging Cross-Currency Portfolio Option with Stochastic Interest Rates

王祥安, Wang , Hsiang-An Unknown Date (has links)
在WTO成立,各國國際化程度日益提高的同時,企業與個人進行跨國投資的情形也愈來愈普遍,跨國投資除了要考慮標的資產之報酬與波動性之外,尚須考量匯率變動所產生之風險與不確定性。當某一國外資產具有正向預期報酬率的同時,實現後的報酬率卻又不一定為正,正是因為匯率波動所產生的影響。又,傳統財務理論告訴我們,藉由增加投資組合中所有非完全正相關的資產個數可以有效的降低投資組合的非系統風險,因此投資人在進行投資時往往採用建構投資組合的方式取代持有少數資產的型態。然而,在建構跨通貨避險投資組合時,若是對於投資組合中的各項資產與外幣分別進行避險(分別利用衍生性商品避險),往往是費時、費力又不具有效率。因此,對於整個投資組合進行避險反而是一個比較好的方法,當投資組合價值發生變動時,可以即時對於各項資產部位與外幣分別做調整,遠較於對個別資產進行避險來的方便、快速且有效。 / In most cases, investment is made of building a portfolio rather than single asset. Therefore, it is necessary to develop techniques of valuing portfolio derivatives. Moreover, we consider a cross-currency portfolio that account for currency and interest rate risk. As interest rate is stochastic, we use Heath-Jarrow Morton (HJM) Approach to describe its dynamics. Applying Vorst (1992); Geman, Karoui and Rochet(1995), we derive the approximated close-form of the cross-currency portfolio option. In HJM Approach, it is difficult to acquire hedge ratios of options. We apply another method to build a hedging portfolio. Then, we perform numerical simulations to test its hedging efficiency and sensitivity with respect to different variables.
95

國防經濟的成長與福利分析—隨機內生成長模型的應用

李政德, Lee, Cheng-Te Unknown Date (has links)
本論文包括三篇有關「國防經濟」相關議題之研究。此三篇研究建立隨機的內生性成長模型,進行國防經濟的成長與福利分析,整個論文的主軸及行文順序如下: 第一篇文章為「國防支出、隨機成長與福利」,本文主要係延伸Barro (1990)、Turnovsky (1999) 與Gong and Zou (2003) 所提政府支出具生產力的概念,建構一個隨機的內生性成長模型,探討國防支出對於長期經濟成長率與福利水準的影響。我們發現國防支出與長期經濟成長率的關係是非線性的,並且得到使得長期經濟成長率最大時的最適國防支出比例。此外,我們也證明國防支出會透過兩種管道影響福利水準:第一種管道為國家安全效果,第二種管道為經濟成長效果。最後,本文首先提出國防支出波動程度對長期經濟成長率以及福利水準的衝擊會受到生產與國防支出干擾項的共變數以及代表性個人的風險偏好程度所影響。 第二篇文章為「軍事威脅、隨機成長與福利」,本文係延伸第一篇文章的架構,加入軍事威脅的隨機過程,並建構一個隨機的內生性成長模型,除了得到第一篇文章的結論外,更得到外國軍事支出的成長與本國長期內生成長率成反比以及外國軍事支出的波動程度與本國長期內生成長率成正比的結果。此外,本文亦首先證明外國軍事支出的成長與波動程度對於福利水準與長期經濟成長率的影響是相同的。換言之,若外國軍事支出的成長與波動程度導致長期經濟成長率增加,則福利水準也會增加;反之亦然。 第三篇文章為「軍事威脅、成長與福利:小型開放隨機成長模型」,本文建構一個小型開放的隨機內生性成長模型,探討外國軍事威脅對於本國長期經濟成長率與福利水準的影響。本文首先證明外國軍事威脅未預期的干擾對於本國長期經濟成長率的影響與本國是否為債權國或債務國有關。我們也首先證明外國軍事威脅的波動程度對於經濟成長率隨機過程變異數的衝擊會與本國是否為債權國或債務國以及消費的跨期替代彈性有關,即我們證明如果本國為淨債權國且消費的跨期替代彈性大於1或者如果本國為淨債務國且消費的跨期替代彈性小於1,此時若外國軍事威脅的波動程度愈大,則本國經濟成長率的隨機調整路徑愈平穩。
96

研究Ferguson-Dirichlet過程和條件分配族相容性之新工具 / New tools for studying the Ferguson-Dirichlet process and compatibility of a family of conditionals

郭錕霖, Kuo,Kun Lin Unknown Date (has links)
單變量c-特徵函數已被證明可處理一些難以使用傳統特徵函數解決的問題, 在本文中,我們首先提出其反演公式,透過此反演公式,我們獲得(1)Dirichlet隨機向量之線性組合的機率密度函數;(2)以一些有趣測度為參數之Ferguson-Dirichlet過程其隨機動差的機率密度函數;(3)Ferguson-Dirichlet過程之隨機泛函的Lebesgue積分表示式。 本文給予對稱分配之多變量c-特徵函數的新性質,透過這些性質,我們證明在任何$n$維球面上之Ferguson-Dirichlet過程其隨機均值是一對稱分配,並且我們亦獲得其確切的機率密度函數,此外,我們將這些結果推廣至任何n維橢球面上。 我們亦探討條件分配相容性的問題,這個問題在機率理論與貝式計算上有其重要性,我們提出其充要條件。當給定相容的條件分配時,我們不但解決相關聯合分配唯一性的問題,而且也提供方法去獲得所有可能的相關聯合分配,我們亦給予檢驗相容性、唯一性及建構機率密度函數的演算法。 透過相容性的相關理論,我們提出完整且清楚地統合性貝氏反演公式理論,並建構可應用於一般測度空間的廣義貝氏反演公式。此外,我們使用廣義貝氏反演公式提供一個配適機率密度函數的演算法,此演算法沒有疊代演算法(如Gibbs取樣法)的收斂問題。 / The univariate c-characteristic function has been shown to be important in cases that are hard to manage using the traditional characteristic function. In this thesis, we first give its inversion formulas. We then use them to obtain (1) the probability density functions (PDFs) of a linear combination of the components of a Dirichlet random vector; (2) the PDFs of random functionals of a Ferguson-Dirichlet process with some interesting parameter measures; (3) a Lebesgue integral expression of any random functional of the Ferguson-Dirichlet process. New properties of the multivariate c-characteristic function with a spherical distribution are given in this thesis. With them, we show that the random mean of a Ferguson-Dirichlet process over a spherical surface in n dimensions has a spherical distribution on the n-dimensional ball. Moreover, we derive its exact PDF. Furthermore, we generalize this result to any ellipsoidal surface in n-space. We also study the issue of compatibility for specified conditional distributions. This issue is important in probability theory and Bayesian computations. Several necessary and sufficient conditions for the compatibility are provided. We also address the problem of uniqueness of the associated joint distribution when the given conditionals are compatible. In addition, we provide a method to obtain all possible joint distributions that have the given compatible conditionals. Algorithms for checking the compatibility and the uniqueness, and for constructing all associated densities are also given. Through the related compatibility theorems, we provide a fully and cleanly unified theory of inverse Bayes formula (IBF) and construct a generalized IBF (GIBF) that is applicable in the more general measurable space. In addition, using the GIBF, we provide a marginal density fitting algorithm, which avoids the problems of convergence in iterative algorithm such as the Gibbs sampler.
97

供應鏈的評價:實質選擇權分析法 / Evaluation of a supply chain:a real pptions approach

王偉弘, Wang, Wei Hong Unknown Date (has links)
本論文主要是以實質選擇權分析法對在最適決策下供應鏈及公司的價值進行評價。內容包含兩篇文章。第一章為緒論;第二章與第三章為主文。在此兩章中 ,我們會先介紹研究動機、目的與文獻探討,接著架構模型,據以求出於最適決策下供應鏈或公司價值的封閉解後,以比較靜態分析法分析各參數對供應鏈或公司價值的影響。第四章為總結。 / 第一篇文章為對在隨機成本下供應鏈的評價。該模型是以單一供應商、單一零售商與多個消費者組成之垂直整合的二階段序列式動態供應鏈為架構,假設市場的現貨價格為動態過程,供應商和零售商每單位商品的成本為隨現貨價格變動的隨機成本。在此模型中,供應鏈的經營者以銷售量為決策,聯合利潤最大化為目標。此外,存貨設定在零售商的一方,而零售商所持有的存貨可視為擁有一個無窮期的美式買權,當存貨出清時,如同執行一個美式買權一般,以促使利潤的實現。接著我們利用比較靜態分析法就無風險利率和現貨價格報酬率的波動度對於最適決策下所求得的供應鏈價值之影響進行分析後,得到供應鏈價值會隨著無風險利率的上升而增加,亦會隨著現貨價格報酬率波動度的提高而增加。此結論和Cortazar and Schwartz(1993)以兩階段製造產品為運作模式之公司價值就無風險利率和現貨價格報酬率的波動度進行比較靜態分析後所得到的結果一致。 / 第二篇文章為對在隨機匯率下兩階段生產之公司進行評價。此文考慮Cortazar and Schwartz(1993)的模型,在產品之製造為兩階段式生產的條件下,納入隨機匯率,用實質選擇權分析法,評價以外銷專案為標的之公司價值。我們針對模型中的參數:本國的無風險利率、以外幣計價之現貨價格報酬率波動度及匯率波動度的變化對公司價值的影響進行分析後,而得到這些參數與公司價值呈現正相關的結果。此外,因動態現貨價格與隨機匯率的相關性 ,我們亦分析現貨價格和匯率的相關係數對公司價值之影響後,得到兩者正相關程度越大或是負相關程度越小時,公司價值就越大,從而體認到僅從匯率走勢的升值或貶值來判斷外銷專案價值有利與否是不夠詳盡的,還要考慮現貨價格和匯率交互影響的程度,決策者才能做出有利於外銷專案更好的決定。 / 最後,我們將此兩篇文章歸納出一些重要的結論後,接著針對本論文研究主題的未來發展方向,提出一些觀點和建議,以作一個總結。 / This text uses a real options approach to price the value of the supply chain or the company. It contains two articles . Chapter 1 is the introduction; Chapter 2 and Chapter 3 are the main text.In these chapters, we introduce the study motive and literature review, the model, the closed form of the supply chain or the company in the optimal operating policy, and then use comparative statics method to analyze the effect of some parameters that risk-free interest rate, volatility of the spot price, volatility of the exchange rate etc. Finally, we give a summary. / The first article is in Chapter 2. It is to price the optimal value of the two echelon sequential dynamic supply chain which is composed of one supplier, one retailer and many consumers. In this model, we assume that the spot price of goods is a dynamic process, the costs of the per unit goods of supplier and retailer are up to the change of the spot price, the sales volume is the decision strategy, and their aim is to maximize joint profits. In this supply chain, the value of the stocks for retailer can be regarded as a perpetual American call option. Finally, we will use comparative static to examine the effect of the volatility of the spot price and risk free rate for the optimal value of the supply chain, and we obtain the same results as Cortazar and Schwartz’s (1993) optimal value of two-stage companies. / The second article is in Chapter 3. Based on the extended the Cortazar and Schwartz (1993) model, we use the Real Options Approach to price the closed form of the value of the two-stage production for a company under stochastic exchange rate. With regard to the parameters in the model: domestic risk-free interest rate, the volatility of the foreign spot price, and the volatility of the exchange rate, we find that the domestic risk-free interest rate, volatility of the foreign spot price, and the volatility of exchange rate have positive correlated with the optimal value of the company. Moreover, due to the correlated relation between the dynamic foreign spot price and the stochastic exchange rate, we analyze the change of the coefficient of correlation between the foreign spot price and the exchange rate, and obtained the more large optimal value of the company when they are more large positive correlated or negative correlated. In other word, we need to consider the influence between the foreign spot rate and the exchange rate at the same time, and then the manager can make the optimal decision about the exporting project. / Finally, we summed up some important conclusions of Chapter 2 and Chapter 3, and then proposed some views and suggestions for the study the theme and the developing direction in the future.
98

亞洲生技醫藥產業之生產力與效率分析 / The Productivity and Efficiency Analysis of Biotech Pharmaceutical Industry in Asia

蕭雅茹 Unknown Date (has links)
各國視生技產業為未來發展的關鍵產業,並積極推動各項政策,使生技產業能快速成長,而生技醫藥市場是促成全球生技產業成長的主要動力,為了增加我國的競爭力,希望藉由與鄰近國家醫藥產業的比較,能更了解台灣生技醫藥產業經營績效。 本研究採用Battese and Coelli (1995)隨機成本邊界法,針對2002-2007年間,日本、南韓、中國、印度與台灣等五個國家,共61家生技醫藥廠商進行實證分析,研究結果如下:(1)研發密集度增加使成本效率降低,五個國家裡,日本最具成本效率。(2)產業平均成本效率值為0.855,且有逐年惡化的趨勢。(3)整體產業平均處於遞增規模報酬階段。(4)整體而言,總要素生產力(TFP)的提升主要是因為規模成分的貢獻,其次為技術的進步,而技術效率變動率對TFP成長率為負影響。(5)各國間雖然TFP變動率不存在顯著性差異,但在規模成分、技術變動率與技術效率變動率等方面存在著顯著的差異。 / Many countries regard biotechnology as a key industry for the future development. Governments often implement a variety of policies to help it grow rapidly. The biotech pharmaceutical industry is the main momentum for the growth of the global biotech industry. The objective of this paper is to measure the productivity and efficiency of the industry among Asian countries, and investigates the sources of the performance changes, and then hope to give some insight into the enhancement of the industry’s productivity. To pursue our goal, we adopt Battese and Coelli’s (1995) stochastic frontier approach to assess 61 biotech pharmaceutical firms during 2002-2007. The main empirical results can be summarized as follows: (1) The R&D intensity is negatively related to cost efficiency; in five countries, Japan has the highest cost efficiency. (2) On average, the cost efficiency is about 0.86, and has become worsen year after year. (3)Most of time, the industry is characterized with the increasing returns to scale. (4) The growth of total factor productivity (TFP) is mainly attributed to the scale efficiency change, and technical progress accounts for a minor source. However, technical efficiency deteriorates over time. (5) Among countries, the TFP growth rates have no significant differences, but the components show apparent differences.
99

影響台灣民眾離婚態度變遷之研究:年齡-時期-世代的分析

鄭郁芳 Unknown Date (has links)
現代化與工業化改變了人們的生活方式,也對傳統的家庭型態與關係造成莫大的影響。在世界各國,同樣也面臨家庭解組、傳統價值逐漸瓦解的問題,隨著離婚率的逐年攀升,傳統家庭道德對現代人的規範力逐漸式微。這些現象意味著,若我們要理解台灣家庭或婚姻情況的真實樣貌,我們必須得先瞭解影響台灣離婚率和行為背後的離婚態度為何?而影響離婚態度的因素又是什麼? 本研究所採用的是台灣社會變遷調查資料庫1984、1995、2000和2005年共四年份的調查資料。在這四年的問卷題組當中,受訪者都被問到「夫妻不合而離婚有沒有錯?」之相同問題。藉由長時期、相同問題重複的資料特性,並結合「階層式年齡-時期-世代別」之分析模型,本研究從個人層次、時期層次和世代層次來探討影響離婚態度變遷和差異的重要因素,進而描繪出台灣社會在過去二十多年的變遷軌跡。 本研究發現:首先,因為在婚姻市場上男性獲益較大,且女性隨教育提升、經濟獨立機會大增,女性對於傳統的婚姻價值會比男性更易鬆動,並且較能接受離婚。其次,男性和女性隨生命歷程的轉變,年齡效果沒有呈現非線性關係的倒U型趨勢。第三,在戰後嬰兒潮時期以及嬰兒潮之後出生的世代,對於離婚行為傾向較能接受;反之,出生於戰前和二戰期間的世代,對於離婚行為都會比較保守。第四,當外在社會瀰漫著一股離婚的風氣時,個人容易受周遭同儕和整體環境的影響,覺得離婚並非一件負面的事情,形成離婚世俗化的潮流,所以當社會的總體離婚率愈高的時候,人們的離婚態度就會愈開放。另外,在自變項與控制變項方面,受過高等教育者和白領職業的女性,其對離婚行為會偏向贊同和接受,而有宗教信仰者則會傾向保守並反對。
100

台灣上市櫃證券商經營效率與生產力變動之分析-隨機距離函數之應用 / Operational efficiency and productivity change of listed securities firms in Taiwan-an application of stochastic distance functions

張佩茹, Chang, Pei Ju Unknown Date (has links)
本文採用一階段隨機邊界分析法(Battese and Coelli, 1995)衡量2004 年第一季至2008 年第三季台灣上市櫃證券商的技術效率,並將Orea(2002)提出的產出導向一般化Malmquist生產力指數改寫成投入導向模式,用來分析台灣上市櫃證券商的生產力變動情形。實證結果顯示,小型券商之經營效率平均而言比大型券商之經營效率高,而大部分的證券商都呈現規模報酬遞增的技術狀態,可見台灣上市櫃證券商整體而言規模不夠大,必須設法再擴大至適當的規模方可發揮規模經濟效果。另外,較多的股本雖然理論上具備較強的競爭優勢,但可能沒有適當的決策支持,造成資源浪費反而降低經營效率;股價指數愈高,在相同的投入之下有較多的產出表現且較有能力調整規模至規模報酬較佳的狀況,因而提高經營效率。 / This paper adopts one-stage stochastic frontier analysis (Battese and Coelli, 1995) to measure technical efficiency of listed securities firms in Taiwan from the first quarter of 2004 to the third quarter of 2008. In addition, inspired by the Orea (2002) output orientated productivity model, this paper derives an input orientated generalized Malmquist productivity index to analyze the productivity change of the firms. The empirical results reveal that smaller securities firms are more efficient than larger securities firms in average. The majority of securities firms are operating with increasing returns to scale, indicating that the scale of listed securities firms in Taiwan are generally not large enough, so firms need to enlarge their scale in order to get the effect of economies of scale. Although more capital stocks possess stronger competitive advantage theoretically, without proper strategy to support the firms may waste resources and result in operational inefficiency. Operational efficiency is positively correlated with stock index.

Page generated in 0.0245 seconds