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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.
11

無線網狀網路中干擾感知之拓樸控制的研究 / Interference-Aware Topology Control in Wireless Mesh Network

方任瑋, Fang, Ren Wei Unknown Date (has links)
在無線網狀網路(Wireless Mesh Network)中,每個節點須幫助相鄰節點轉送資料及提供使用者網路存取,例如WLAN(IEEE 802.11s)、WMAN(IEEE 802.16)等,皆可利用多跳接方式將資料轉送至通訊閘道器(Gateway)。在無線網狀網路中,常利用密集佈建的方式來解決通訊死角的問題。當網路節點的密度增加時,無線訊號的干擾也會增強,並且各節點的效能會顯著下降。 在本研究中,將利用幾何學概念,解決網路干擾問題,並提出拓樸重建演算法來重建路徑,使網路干擾達到最小化。我們試著最小化節點與節點間的干擾,以提升整體無線網狀網路效能。我們將網路問題轉換成幾何問題,並定義在幾何圖形中線段交錯問題,之後驗證在幾何圖形中是否有線段交錯的現象發生。若發生線段交錯時,則將此線段從幾何圖形中移除,並且利用三角化演算法將此區域線段重新規劃,使相鄰節點間的干擾最小。當網路拓樸建立完成後,我們利用標準差公式將干擾較大的連線移除,使得網路效能提升。上述測試線段交錯及三角化多邊形演算法可在時間複雜度O(n log n)內找到干擾最小的解。最後,我們將利用網路模擬器(Network Simulator)驗證所提出的方法是否能達到預期的系統效能指標。 / In wireless mesh networks, such as WLAN (IEEE 802.11s), WMAN (IEEE 802.16), etc., each node should forward packets of neighboring nodes toward gateway using multi-hop routing mechanism. In wireless mesh network, as the density of network nodes increases, the RF interference will increase and the throughput of each node will drop rapidly. In our research, we use the geometry to resolve the RF interference problem by rebuilding network topology. We try to minimize the interference between neighboring nodes and improve the throughput in wireless mesh network. We transform the network topology problem into geometry problem and define the line intersection problem in geometric graph, then check path intersection in the geometric graph. If line intersection occurs in the graph, we remove the intersection line from the graph and re-plan the region by triangulation algorithm. When the network topology is built up, we use a standard deviation formula to improve network performance by removing longer links. The line intersection algorithm and triangulation algorithm, both of time complexity O(n log n), are used to find the minimal interference solution. At the end of our research, we use network simulator to verify if the proposed methods can help to meet all those performance expectations.
12

應用6 Sigma 導入EuP 綠色專案之個案研究 / Six Sigma Management for EuP Green Program - A Case Study

許瑞鵬, Hsu, Juey Peng Unknown Date (has links)
今 (2008) 年,全球規模排名前三大的電腦展,從1月開始美國拉斯維加斯的CES展、3月的德國漢諾威的CeBiT展,到6月在台北的Computex展,數千家之參展廠商,數十萬之買主與參觀人士,不約而同,大家的主訴求都是「綠色」與「節能」。向來,三大電腦展都是未來產品的風向球,加上從美國前副總統高爾的紀錄片「不願面對的真相」看到地球暖化現象日益嚴重,石油價格也不斷再創歷史新高,的確讓人感到這個世界將變得更為綠色,當人們愈來愈重視自己居住的這個環境與資源,也宣告「綠色產品、綠色消費」的時代正式來臨。 近年來一波波的綠色浪潮,如同過去十餘年間的網路興起,所產生巨大的改變一般。全球環保意識覺醒,尤以歐盟一向以高環保標準為最,陸續在2005年8月起推行的三大環保指令:WEEE(回收化)、RoHS(無毒化)、EuP(節能化),超過80%的環境衝擊都跟產品設計有緊密關聯;是故,整合環境考量因素而成綠色產品的生態化設計作法,將會是企業最有效的方法。 上述WEEE 及RoHS兩項已於2006 年7月1日後,正式對輸出到歐盟各國的產品中全面實施管制,而日本、韓國、中國等國及美國(部分州)等,亦在2007年初立法通過並已實施,此股全球化之綠潮,已是勢不可擋;第三項的EuP (Energe using Product)「耗能使用產品之生態化設計指令」,歐盟各國已大多立法制定完成,部分國家還一併通過違規罰則,預計在2009年第一季起開始啟用,屆時勢必又將再度啟動第三回合的環保大挑戰。 我國對歐盟之貿易額佔了總體的比重極大,於2007年,我國出口到歐盟各國之電機、電子產品等金額超過逾NT$3,000億,企業也決不容忽視這廣大的市場商機。本研究的個案公司向來對環保意識相當重視,亦積極地關注在永續發展與環保議題上,所設計製造的綠色產品也行銷全球;現今的設計趨勢都以綠色、節能為導向,身處電子、電機產業的一員,面臨這項嚴峻之挑戰,更需即早因應,通過這些環保規範檢測,才能確保產品順利銷往歐盟。 本研究乃透過個案公司於過去三、四年中,利用 6 Sigma 的DMAIC循環改善手法,搭配ISO 9000/14000品質/環境管理系統以有效整合,組成專案團隊運作,成功導入6 Sigma WEEE / RoHS等專案,且比2006年7月1日的法定實施期限日,提早一季的時間完成歐盟WEEE及RoHS所有綠色產品之設計,並在符合法定時程/品質要求/客戶滿意等情況下順利出貨。 爰此,以綠色設計為整體考量因素,建置成一套標準化的流程機制,應用到EuP新環保規範中,進行產品節能、生命週期等多項評估,提升生態化設計能力。EuP雖與RoHS/WEEE的指令訴求內容互異,但本著6 Sigma RoHS過去分析及改善等手法,藉由嫻熟運作之科學管理模式,來縮短研發時程;目標為:提早一季時間完成產品設計,且品質符合環保規範驗證之出貨準備;期間雖會遭遇諸多問題與困難,但以6 Sigma經驗豐富之優秀成員組成的團隊,將採絕佳默契、合作無間的精神,順利於今年底達成任務,也為個案公司大幅提升環保戰力之全球競爭優勢。 關鍵字:限用有害物質指令、耗能使用產品指令、生態設計、國際標準組織、六標準差專案管理。 / In the world’s top three exhibitions of the electronic industry this year - namely CES of Las Vegas in January, CeBIT of Hanover in March, and Computex of Taipei in June, the main theme is the same: Green Technology and Energy Saving Products. Mr. Al Gore’s ‘Inconvenient Truth’ has unfolded future disasters caused by global warming, together with recent oil price hikes over US$140 a barrel, all these environmental and energy crisis have hastily ushered in the ‘Green Product Epoch.’ The European Union led the wave of Green Products by issuing the WEEE (Waste Electrical Electronic Equipment) directives in August 2005 which aimed at reducing E/E waste disposal through reuse, recycle and recovery, followed by the RoHS (Restriction of Hazardous Substance) directives enforced on July 1, 2007. EuP (Energy using Product) is the latest set of directives which will be implemented in 2009. Since more environmental impacts relate to product design, the green product ecological design incorporating environmental factors is most effective method. These regulations will greatly affect members of global E.E product supply. Taiwan had a big trade count with EU in the past time, so it will be caused more impacted as well. Therefore, many countries have regulated new national standards, many Taiwanese firms are making great efforts on the issues of Eco Design for energy saving to meet the trend on environment protection as earlier as possible and to provide operational producers for the business toward green global supply chain. For enterprises to implement environmental management system and to establish green product design and production by ISO9000 / ISO 14000 systems, and there are many procedures, validation and testing need to by 6 Sigma DMAIC improvement methodology. This case study proposes a model to include the RoHS green product into quality system successfully in 2 years ago, next case is provided to verify the model and justify how a firm can efficiently use the proposed model and empirical experience to meet product certification requirement into the system. The findings of this research can support other enterprises to implement appropriate model to integrate green product with framework of ISO9000/14000 quality/environment management system by 6 Sigma process. This is also suitable for a firm to upgrade its management system to meet various green requirements as WEEE, RoHS and EuP. The study is still enphasised many Taiwan manufacturers are tempted by the success of 6 Sigma in the western world and are now in the process of introducing 6 Sigma into their organizations. The push to further reduce costs has urged the firms to use 6 Sigma to regain their competitive positions in the global economy. Keywords: RoHS, EuP, Eco Design, ISO, 6 Sigma Managment
13

類神經網路應用於房地產估價之研究 / The application of neural network to real estate appraisal

高明志, Kao, Ming-Chih Unknown Date (has links)
估價於房地產市場實扮演著一不可或缺的角色,精確的估價不僅可提供消費者正確極充分的購屋資訊,亦為政府擬定政策方針之基礎。由於台灣房地產市場為一不完全市場,消費者在購屋的同時更常因資訊的不健全而遭受不必要之損失,因此精確及流通之估價資訊實為健全台灣房地產市場之首務。 鑑於過去估價技術仍未成熟,所佔之房價常無法令人信服。本研究欲以類神經網路之功能,將其原理應用於房地產估價上,試圖解決過去估價方法本身之缺失,並作為估價人員輔助之工具。本研究主要以倒傳遞及理解倒傳遞類神經網路與特徵價格法進行公證比較分析,並以特徵價理論為基礎,利用類神經網路得出影率房地產價格更具代表性之因素,以做為未來建立房地產估價輔助系統之參考。 為了解不同的資料型態是否會使類神經網路有不同的學習效果,本研究將資料分為四組實驗設計,分別對不同的資料型態進行測試,研究結果顯示類神經網路對於資料型態較為敏感,其中又以理解倒傳遞類神經網路為最,使得其在預測能力上易受異常點或極端值的影響,而有好壞差異較大的情況。即類神經網路之學習效果端視資料是否具代表性而定。

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