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  • 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.
61

適用於無線隨意式網路之逐節點TCP傳輸協定 / Hop-by-Hop TCP over MANET

游逸帆, Yu,Yi-Fan Unknown Date (has links)
行動隨意式網路(MANET)是一種具有高度動態拓撲結構的網路。每一個行動隨意式網路由一組移動節點(Node)組成,彼此之間互相支援轉送封包可以不依靠基地台建構成Intranet。此種網路中,因節點移動之緣故,連線不穩定、頻寬較窄,錯誤率亦較高。傳統的TCP傳輸協定在行動隨意式網路上的效能不免遭受重創。 傳統的TCP在封包遺失時,只能從傳送端進行重傳,而行動隨意式網路傳輸品質極不穩定,常常重送多次才可到達目的地,導致要耗費極長的時間才能將封包送達目的地,然而,在行動隨意式網路中,大量傳輸資料的需求並不大,反而是封包的快速送達更為重要,因此加速封包的送達成為比增大傳送量更為重要的目標。 為了使封包較快送達目的地端,我們提出了Hop-by-Hop TCP的方法,使每個節點使用當地重傳以保證封包成功的傳到下一個節點,遺失的封包不必重新由傳送端重傳,能更快反應封包遺失,並且提昇傳輸可靠度,使封包在高遺失率的情形之下能順利且較為快速的送達目的地端。 我們利用NS-2網路模擬器進行實驗,驗證我們的機制,實驗在不同的拓樸及負載等參數下進行,觀察傳輸成功率及封包傳輸時間,以及公平性。實驗結果指出,本方法在網路環境不穩定時吞吐量能有25.7%以上的提昇,而延遲時間也能有25%的提昇,亦有相當好的公平性。 / A Mobile Ad hoc Network (MANET) MANET is composed of a group of mobile computing devices (nodes) that are equipped with Wireless LAN (WLAN) capability. Nodes can transmit packets to each other to construct Intranet without any base station. In an MANET environment, the communication links are unstable due to various reasons. Error rate is higher and bandwidth is smaller than fixed networks. Running regular TCP protocol on MANET will suffer from serious performance degradation in MANET. To handle packet lost, regular TCP can only retransmit lost packets from the source. However, when error rate is high, several retransmissions may be needed to transmit a packet to its destination successfully. As a result, the effective bandwidth is much lower and the average time to transmit a packet will be much longer. Considering that most applications on MANET prefer shorter transmission time to higher bandwidth, this thesis proposes Hop-by-Hop TCP protocol aiming to accelerate the transmission of packets. Hop-by-Hop TCP makes every intermediate node in the transmission path running a local TCP to guarantee the transmission of each packet on each link. The retransmission of a lost packet is right at the transmitting end of the link where the packet is lost. It doesn't need to retransmit a lost packet from its source node. It takes less time in average to transmit a packet to its destination in a high error rate environment. We evaluate the performance of our approach by simulation using NS-2 simulator. Our experiments show that our proposed protocol outperforms TCP Reno by 25.7% in throughput and 25% reduction in average transmission time. The fairness requirement is also achieved while our proposed protocol coexists with other major TCP variants.
62

新巴塞爾資本協定下電子業信用評等羅吉斯模型建置

林郁翔 Unknown Date (has links)
近年來銀行經營管理方式已因經濟環境改變及金融市場變遷而產生了巨大變革,商業銀行的資產規模是不是可以無限制地擴張?銀行經營績效的評估方式仍可用傳統盈餘及成本觀念加以框架嗎?在此背景下,巴塞爾資本協定應運而生。1987 年,美聯儲和英格蘭銀行聯合向巴塞爾清算委員會提出要在世界上建立共同的資本體系,目的就是要限制在資本不足的情況下銀行規模的過度擴張;現代金融機構經營績效的評估亦不再僅是單純存放款利差的擴大,而更由考量「每單位資本」所得利潤,轉變為衡量「每單位風險」下所能創造的獲利。藉由這種思維轉變所產生的評估指標,較能忠實呈現風險下的真正績效,並有效掌握銀行內部風險程度及獲利狀況,對資金與稀少性資源做適當分配。 如何達到最佳化的資本配置?最主要在於精確量化銀行業者每天所面臨的各項風險,尤其是信用風險的量化。而信用評等(credit rating)制度的建立係現代商業銀行量化信用風險管理的最重要且最基本的一環,信用評等的建置成敗在於資料倉儲的品質與IT 支援能力,這也是銀行內部評等建置的基楚工程,而一般大型國際銀行在建置內部評等系統時,會一併將後續呆帳準備(provisions)計提、預期損失與未預期損失、資本配置管理與風險調整後績效評估連結。 本研究室針對電子製造產業,在新巴賽爾協定規範下,建立信用評等模型。模型採用羅吉斯迴歸建立,模型中的變數可分成三個構面:『董事持股面』、『公司獲利面』、『公司負債面』;而模型的整體正確率可達88.31%。在各項模型的測試中,皆有穩定的表現。
63

應用資料採礦技術建置符合新巴塞爾協定之信用風險模型–以傳統產業為例

徐慧玲 Unknown Date (has links)
巴塞爾銀行監理委員會於2001年1月公布新版巴塞爾資本協定,並於2006年底正式實施。新協定鼓勵銀行能建立自己的內部評等系統評估違約風險,並重視銀行放款風險考量資訊的量化和降低計提所需資本,進而提高金融機構風險敏感性,以彌補傳統標準法的不足。為因應此趨勢,本研究以全國公開資料庫的資料為實例,資料的觀察期間為1996至2005年,透過資料採礦流程,以製造傳統產業公司之授信樣本為主要的研究對象,建構企業違約風險模型及其信用評等系統。 本研究分別利用類神經網路、羅吉斯迴歸和C5.0決策樹三種方法建立模型並加以評估比較其預測能力。結果發現羅吉斯迴歸模型對違約戶的預測能力及有效性皆較其他兩者為佳,因此,以羅吉斯迴歸方法所建立的模型為本研究最終模型。接下來便針對該模型進行各項驗證,驗證後發現此模型即使應用到不同期間或其他實際資料,仍具有一定的穩定性與預測效力,確實能夠在銀行授信流程實務中加以應用。
64

WTO協定間法律適用關係之研究 / A Study on the overlaps between provisions in WTO agreements

張南薰, Chang,Nan Hsun Unknown Date (has links)
關於WTO協定間條文與條文間之適用關係,依據小組所建立的原則,即基於WTO協定係屬一體承諾之性質,WTO協定下之義務應屬累積的義務,會員在任何時點均應遵守所有的義務,除非有形式上的衝突存在。然而,整個WTO協定包括了馬爾喀什建立WTO協定、商品貿易多邊協定、服務貿易總協定、智財權等不同部門的協定,到決議文、瞭解書等,有多達六十多種不同的法律文件。這些法律文件是在不同時期及不同背景下,經由不同的談判者所協商而成,而談判者在談判當時,對於各項法律文件間之關係未必有所認知並進一步地為適當的安排,因此未預見的重複、漏洞或衝突,即有可能產生。對於WTO協定條文間錯綜複雜的關係,WTO實務在若干案件中雖有所著墨,但對於何時應屬累積適用及何時構成法律衝突而具有排除適用之效果,並無一致性的判斷標準存在,因此本文即希望透過將WTO協定間法律適用關係之類型化,進而歸納出應屬累積適用關係及排除適用關係的條文,並尋求體系化及一致性的的判斷標準。 / Because of the Uruguay Round negotiations brought about a 'single WTO package' at a very late stage of the negotiations, the WTO system itself has not clearly regulated the issue of the possible relationships between provisions in GATT 1994 and other Annex 1A Agreements or provisions in different Agreements. The only linkages set out in WTO law are one general rule of prevalence, in case of conflict (the General Interpretative Note to Annex 1A) and several cross-references in individual Agreements. The authors submit that panels and the Appellate Body have so far identified four relationships between provisions of the WTO Agreements, which can be characterized as conflict, express derogation, confirming, and complementarity. These relationships have different legal effects on the application of the provisions concerned. Although it is not excluded that over time more types of relationships will be identified and developed, it is useful to take stock of the case law setting out the possible linkages. While not purporting to be exhaustive, the present work is an attempt to analyze the cases that appear to be the most significant for clarifying the different relationships.
65

資料採礦於建立內部評等法之信用風險評等模型

李俊毅 Unknown Date (has links)
新巴塞爾資本協定的誕生為全球廣大的金融體系定下一個控制風險的準則,要求金融機構對於其自身風險提列一定的資本準備,以避免發生危機時,毫無應變的能力。金融機構若能依內部評等法計算出對應其自身風險的最低計提資本,即可在風險控制下避免準備過多的資本,以追求最大的利潤。 本研究對象為國內於1996至2005年分類為電子工業下之授信企業,違約企業佔總體資料5.51%,本研究遵循新巴塞爾資本協定中內部評等法之規範,及考量實務應用之普遍性與準確性,以羅吉斯迴歸法建置信用評等模型,並依金管會所建議之方向逐一對模型加以驗證,以符合在實務上運作之標準。 違約機率模型中包含了四個財務報表之變數,一個企業基本特性變數,根據拔靴驗證,不僅在AUC項目的表現相當良好,此模型之參數表現亦相當穩定,不受訓練外樣本而有所明顯的變動。在敏感度分析中,變動某一參數至最差信用等級,皆會讓違約機率有明顯上升。本研究授信資料一共橫跨十年的時間,符合內部評等法中需要五年以上歷史資料的要求,信用評等在轉移矩陣中的表現十分優秀,大致集中在對角線的部分,且幾乎沒有發生在前一年度評等為最差等級的企業在下一年度回復至評等最安全的前三等級的狀況。且透過十年間企業評等的轉移情形發現,電子工業產業在十年間大部分企業有下降的情形,僅有少部分是上升的狀況,顯示出電子工業產業在1996至2005此十年間可能有下滑之趨勢。
66

從投信被迫處理結構債-看主管機關對衍生性商品的監理

林意耘, Lin, Yi Yun Unknown Date (has links)
2005年國內債券基金持有的結構債券 - 高達將近新台幣6,000億的部位,在主管機關的行政命令要求下,限期處份出清,虧損部位由投信業者自行承擔,不得損及投資人權益,事件雖然圓滿落幕,各投信業者忍痛吸收將近300億的總虧損金額。 經過十多年的畸形發展,國內債券基金已經隱然成為金融怪獸,主管機關藉由處理結構債一併整頓基金市場秩序,結構債券成為壓倒駱駝的最後一根稻草,讓投信業者慘賠的結構債,只因為背負著衍生性商品的原罪,成為代罪羔羊! 衍生性商品的發展,對於新金融商品的創新,扮演著極重要的功能及元素,以台灣目前的金融環境,產業的發展必須是多元且國際化,不能排除衍生性商品的發展,因此本文借由事件的發展,比較國內外監理機構對衍生性商品的規範,參考歐美主要國家的監管方式,提供台灣主管機關參考,以制訂風險控管及監管適宜的制度,提供業者創新金融商品的發展環境。
67

應用資料採礦技術於信用評等模型之建置-以服務業為例

劉建廷, Liu,Chien Ting Unknown Date (has links)
新巴賽爾協定已於2006年正式實施,國內各金融業為有效控制信用風險,近年來多致力於內部信用評等之建立;本研究透過建置違約預測模型的方式,讓金融機構可採用更科學且快速的方法預測客戶之違約機率,兼顧了金融機構的獲利與安全性。 本研究之研究對象為全國公開資料庫於民國85年至94年的服務業,其中違約客戶佔1.6%,非違約客戶佔98.4%;藉由企業財務報表與基本構面結合經濟變數,經誤差抽樣建立羅吉斯模型;經評估確立以1:2誤差抽樣比例下的羅吉斯迴歸模型效果最佳。接下來便針對模型去評估模型的有效性;最後,更進一步依照該模型所預測之違約機率,建立信用評分等級,同時檢視各等級內客戶之特性。 研究結果發現,以K-S Test以及ROC曲線進行模型正確性評估,本研究之模型有一定水準可以區隔正常授信戶及違約授信戶的能力;等級同質性檢定,也得到了同一等級內違約要素為同質且組內變異小的結果;表示本模型具有一定的穩定性與預測效力。
68

應用資料採礦技術建置中小企業傳統產業之信用評等系統 / Applications of data mining techniques in establishing credit scoring system for the traditional industry of the SMEs

羅浩禎, Luo, Hao-Chen Unknown Date (has links)
中小企業是台灣經濟貿易發展的命脈,過去以中小企業為主的出口貿易經濟體系,是創造台灣經濟奇蹟的主要動力。隨著2006年底新巴賽爾協定的正式實施,金融機構為符合新協定規範,亦需將中小企業信用評分程序,納入其徵、授信管理系統,以求信用風險評估皆可量化處理。故本研究將資料採礦技術應用於建置中小企業違約風險模型,針對內部評等法中的企業型暴險,根據新協定與金管會的準則,不僅以財務變數為主,也廣泛增加如企業基本特性及總體經濟因子等非財務變數,納入模型作為考慮變數,計算違約機率進而建置一信用評等系統,作為金融機構對於未來新授信戶之風險管理的參考依據。而本研究將以中小企業中製造傳統產業公司為主要的研究對象,建構企業違約風險模型及其信用評等系統,資料的觀察期間為2003至2005年。 本研究分別利用羅吉斯迴歸、類神經網路、和C&R Tree三種方法建立模型並加以評估比較其預測能力。研究結果發現,經評估確立以1:1精細抽樣比例下,使用羅吉斯迴歸技術建模的效果最佳,共選出六個變數作為企業違約機率模型之建模變數。經驗證後,此模型即使應用到不同期間或其他實際資料,仍具有一定的穩定性與預測效力,且符合新巴塞資本協定與金管會的各項規範,表示本研究之信用評等模型,確實能夠在銀行授信流程實務中加以應用。 / To track the development of Taiwan’s economy history, one very important factor that should never be ignored is the role of small enterprise businesses (the SMEs) which has always been played as a main driving force in the growth of Taiwan’s export trade economic system. With the formal implementation of Basel II in the end of 2006, there arises the need in the banking institutions to establish a credit scoring process for the SMEs into their credit evaluation systems in order to conform to the new accords and to quantify the credit risk assessment process. Consequently, in this research we apply data mining techniques to construct the default risk model for the SMEs in accordance to the new accords and the guidelines published by the FSC (the Financial Supervisory Commission). In addition we not only take the financial variables as the core variables but also increase the non- financial variables such as the enterprise basic characteristics and overall economic factors extensively into the default risk model in order to formulate the probability of credit default risk as well as to establish the credit rating system for the enterprise-based at risk for default in the IRB in the second pillars of the Basel II. The data which used in this research is taken from the traditional SMEs industry ranging from the year of 2003 to 2005. We use each of the following three methods, the Logistic Regression, the Neural Network and the C&R Tree, to build the model. Evaluation of the models is carried out using several statistics test results to compare the prediction accuracy of each model. Based on the result of this research under the 1:1 oversampling proportion, we are inclined to adopt the Logistic Regression techniques modeling as our chosen choice of model. There are six variables being selected from the dataset as the final significant variables in the default risk model. After multiple testing of the model, we believe that this model can withstand the testing for its capability of prediction even when applying in a different time frame or on other data set. More importantly this model is in conformity with the Basel II requirements published by the FSC which makes it even more practical in terms of evaluating credit risk default and credit rating system in the banking industry.
69

中澳自由貿易協定談判之研究 / A Survey on Sino-Australian free trade agreement negotiations

吳念祺, Wu, Nien-Chi Unknown Date (has links)
自20世紀末期以來,隨著世界經濟區塊化和中國經濟的蓬勃發展,中國已成為澳洲當前最重要的貿易夥伴。在此背景下,澳洲前總理霍華德(John Howard)於2002年5月訪中期間,便主動向中國前總理朱鎔基提出洽簽「澳洲-中國自由貿易協定」(Australia-China Free Trade Agreement, ACFTA)的構想,希望進一步加強兩國之間的經貿聯繫。然而,各國政府推動雙邊自貿談判的目的往往出自於經濟和政治的雙重考量,而中澳自由貿易協定亦不例外。在此認知下,澳洲和中國洽簽雙邊自貿協定之動機和目的,是本文所要探討的重點。筆者將觀察中澳兩國如何在雙邊自貿談判的過程中,為自己創造一些有利的籌碼,進而說服對方以達到目的。另外,本文也將分析中澳自由貿易協定成立之後對中澳兩國的經濟發展、東亞經濟整合、以及台灣總體經濟之可能影響,並就台灣將如何因應區域經貿結盟之風潮提出政策建言。
70

應用資料採礦技術建置台灣中小企業之電子業信用評等模型

陳冠宇 Unknown Date (has links)
全球化潮流方興未艾,基於與國際接軌目標,我國金融業自2006年起實施新巴塞爾資本協定,期於現今日新月異金融環境中以全球一致性的銀行管理方法及制度落實其精神。實施新巴塞爾協定後,首當其衝者便是台灣產業發展主體—中小企業。以信用風險中資本計提為例,中小企業不若大型企業體質健全,且財務透明度亦為人詬病,相對提升金融機構授信風險,進而導致中小企業融資授信審查趨於嚴格與保守,中小企業融資難度與成本皆大幅增加。 有鑑於此,本研究以中小企業中電子業為主要研究對象,採資料採礦流程進行信用評等模型建置。為求配適最佳違約機率模型,分別以不同精細抽樣比例逐一配適羅吉斯迴歸、類神經網路及分類迴歸樹等統計模型,經評估後篩選出羅吉斯迴歸模型建置信用評等系統。再者,為確認模型與信用評等系統建置適當,係遵循新巴塞爾協定相關規範進行各項測試及驗證,結果顯示模型於樣本外資料測試表現良好,信用評等系統亦通過正確性分析、等級區隔同質性檢定及穩定度分析等驗證準則,冀能提供金融機構一套有效且精簡的信用管理機制,建立與中小企業間資訊對稱管道,於兩造雙方取得互利平衡,防範危機於未然。 / Globalization trend is still growing. Because of the objective of connecting to the world, the banking and finance industry in Taiwan has implemented the New Basel Capital Accord since 2006, hoping to make use of globally consistent banking management method and system to implement its spirit in this changing financial environment today. After the implementation of the New Basel Capital Accord, the principal development part in Taiwan industry, medium- and small-sized enterprises, is the first to be affected. For example, with regard to the capital requirements in credit risks, the constitution of medium- and small-sized enterprises is not as sound as large-sized enterprises’, and the financial transparency of medium- and small-sized enterprises is insufficient that the credit risk of financial institution would be lifted comparatively; and then, the finance and credit investigation of medium- and small-sized enterprises would become strict and conservative, thus the finance difficulty and cost of medium- and small-sized enterprises would be increased substantially. In view of this, this study regards the electronics industry from medium- and small-sized enterprises as the main study objects, and data mining procedures are used so as to establish the credit scoring system. To get the best probability model of default, different oversampling ratios are used one by one to match such statistical models and logistic regression, Neural Network Analysis, and C&R Tree; and logistic regression model is selected for the establishment of credit scoring system after assessment. Moreover, relevant the New Basel Capital Accord standards are followed to carry out every test and verification so as to confirm that the establishments of model and credit scoring system are appropriate. The result indicates that the model has good performance in out-sample test, while credit scoring system also passes such verification standards as accuracy analysis, level segment homogeneity test, and stability analysis. Hopefully, this study result can provide a set of effective and simple credit management system for the financial institution to establish information symmetrical channel with the medium- and small-sized enterprises, so that both parties can obtain mutual balance and the crisis can be alerted in advance.

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