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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

Weighted Unranked Tree Automata over Tree Valuation Monoids

Götze, Doreen 14 March 2017 (has links)
Quantitative aspects of systems, like the maximal consumption of resources, can be modeled by weighted automata. The usual approach is to weight transitions with elements of a semiring and to define the behavior of the weighted automaton by mul- tiplying the transition weights along a run. In this thesis, we define and investigate a new class of weighted automata over unranked trees which are defined over valuation monoids. By turning to valuation monoids we use a more general cost model: the weight of a run is now determined by a global valuation function. Besides the binary cost functions implementable via semirings, valuation functions enable us to cope with average and discounting. We first investigate the supports of weighted unranked tree automata over valuation monoids, i.e., the languages of all words which are evalu- ated to a non-zero value. We will furthermore consider the support of several other weighted automata models over different structures, like words and ranked trees. Next we prove a Nivat-like theorem for the new weighted unranked tree automata. More- over, we give a logical characterization for them. We show that weighted unranked tree automata are expressively equivalent to a weighted MSO logic for unranked trees. This solves an open problem posed by Droste and Vogler. Finally, we present a Kleene- type result for weighted ranked tree automata over valuation monoids.
12

有線電視MSO發展數位化之關鍵成功因素:以中嘉網路的資源整合運用為例 / The Key Success Factors of Digitalization of Cable TV MSO:A Case Study on the Resource Integration of CNS

簡嘉威, Chien, Chia-Wei Unknown Date (has links)
近年來,有線電視多系統經營商(MSO)在統合台灣地區各家系統業者的集團化經營模式之下,已逐漸成為國內電訊產業中的主要營運平台之一,其發展也受到眾多產業研究者的重視。隨著全球性的數位電視發展趨勢,以及國內數位傳播科技的蓬勃提升,台灣的四大MSO業者先後在2009年推動數位電視服務,有線電視數位化的市場動能開始浮現,也帶來了國內傳媒產業的嶄新期待。 本文以MSO業者為主要的研究分析對象,輔以系統業者與跨業經營有線視訊服務的中華電信MOD作為交相對應之依據,並以組織資源學理的角度出發,探究有線電視MSO如何以資源運用與整合的方式,來推動數位電視服務。研究發現,原有的收視戶規模、工程技術、人力資源、數位內容與財務規劃等因素,雖然是首要的組織核心資源,但是能否進一步運用內部管理與行銷推廣能力,進而形構出超越傳統市場形象的數位化品牌價值,方為MSO業者的營運思維之關鍵所在。 總體論之,MSO應當將自身調整至電訊服務營運商(Telecommunication Service Operator)的角色定位,並積極引入跨領域背景的未來人才,且必須重視對於旗下系統業者的良好整合與管理、顧客關係管理的妥善執行、雙向互動之科技;而本地內容業者的數位化程度、政策制訂與產業發展的配合亦相對重要。另外,理想的組織外部資源整合,以及明確的數位有線電視服務定位,皆將對於該產業的市場發展性影響深遠。本文亦期盼該研究能對數位有線電視平台業者、內容提供者或其它的相關產業鏈局之業者,產生實質上的參考價值。
13

Graphes et hypergraphes : complexités algorithmique et algébrique

Lyaudet, Laurent 17 December 2007 (has links) (PDF)
Attention, ce résumé comporte un peu d'ironie et d'humour. Dans ce mémoire, nous défendons l'idée selon laquelle, pour tout modèle de calcul raisonnable, ce n'est plus tant le modèle qui compte pour caractériser les classes de complexité importantes que la complexité de la structure combinatoire sous-jacente et en définitive d'un graphe sous-jacent. Pour prendre l'exemple des circuits booléens ou algébriques comme modèles, tout ce qui importe est la complexité du graphe orienté sous-jacent au circuit. Par modèle de calcul raisonnable, nous entendons, comme il se doit, un modèle qui étudié sur une classe de graphes standard nous donne la classe de complexité standard attendue afin de satisfaire aux règles élémentaires des tautologies. On pourrait aussi choisir comme modèles raisonnables les modèles Turing-complet (ou une autre notion de complétude plus adaptée selon les objets calculés), formalisables dans une logique simple (afin d'éviter les "tricheries" et les modèles conçus spécialement pour faire échouer la belle idée défendue). Néanmoins, cette seconde option n'étant pas sans risque, nous nous contentons de la proposer. La thèse défendue est une version un peu plus formalisée et précise mathématiquement de cette idée aux contours un peu flous et qui est donc nécessairement un peu fausse telle quelle.
14

Evaluation of model-based fault diagnosis combining physical insights and neural networks applied to an exhaust gas treatment system case study

Kleman, Björn, Lindgren, Henrik January 2021 (has links)
Fault diagnosis can be used to early detect faults in a technical system, which means that workshop service can be planned before a component is fully degraded. Fault diagnosis helps with avoiding downtime, accidents and can be used to reduce emissions for certain applications. Traditionally, however, diagnosis systems have been designed using ad hoc methods and a lot of system knowledge. Model-based diagnosis is a systematic way of designing diagnosis systems that is modular and offers high performance. A model-based diagnosis system can be designed by making use of mathematical models that are otherwise used for simulation and control applications. A downside of model-based diagnosis is the modeling effort needed when no accurate models are available, which can take a large amount of time. This has motivated the use of data-driven diagnosis. Data-driven methods do not require as much system knowledge and modeling effort though they require large amounts of data and data from faults that can be hard to gather. Hybrid fault diagnosis methods combining models and training data can take advantage of both approaches decreasing the amount of time needed for modeling and does not require data from faults. In this thesis work a combined data-driven and model-based fault diagnosis system has been developed and evaluated for the exhaust treatment system in a heavy-duty diesel engine truck. The diagnosis system combines physical insights and neural networks to detect and isolate faults for the exhaust treatment system. This diagnosis system is compared with another system developed during this thesis using only model-based methods. Experiments have been done by using data from a heavy-duty truck from Scania. The results show the effectiveness of both methods in an industrial setting. It is shown how model-based approaches can be used to improve diagnostic performance. The hybrid method is showed to be an efficient way of developing a diagnosis system. Some downsides are highlighted such as the performance of the system developed using data-driven and model-based methods depending on the quality of the training data. Future work regarding the modularity and transferability of the hybrid method can be done for further evaluation.
15

臺灣有線電視價格管制上限有效性之探討 / A study of the effectiveness of the price cap in the Taiwan's Cable TV industry

蔡國棟, Tsai, Guodung Unknown Date (has links)
從2000年費率主管機關公布有線電視基本頻道收視費用之每月每戶上限為新臺幣600元,並逐年核定其價格上限。本研究透過超越對數成本函數及需求函數,探討我國有線電視2004年至2008年間經營概況,實證結果得知: 一、我國實施價格上限管制法,管制有線電視基本頻道收視費用之機制是具有效性,且費率主管機關近年來價格管制,是增加消費者剩餘方向前進。 二、在每年所核價格上限下,系統經營者平均每戶約新臺幣107元獲利空間;系統經營者對於將所節省的成本反應至收視費用上,是不積極的。 三、有線電視產業之價格需求彈性為-0.8107,顯示有線電視服務已逐漸成為國人生活上的常用品,符合目前社會經濟現象。 四、有線電視產業之家戶所得需求彈性為0.6951,顯示有線電視服務為正常財。 五、有線電視平均成本隨著訂戶數逐年增加而下降趨勢,顯示有線電視產業具有規模經濟特性,其平均成本下降原因主要來自於固定成本下降。 六、系統經營者之邊際成本隨著年度增加而趨向新臺幣300元至400元間集中或收斂。以組織結構來看,各集團5年平均邊際成本在新臺幣348元至405元間。以整體有線電視來看,5年平均值約為新臺幣367元。 七、以組織結構來看,各集團5年平均成本在新臺幣417元至470元間。以整體有線電視來看,5年平均值約為新臺幣438元。

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