• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 38
  • 5
  • 4
  • 3
  • 3
  • 3
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 73
  • 14
  • 12
  • 11
  • 10
  • 9
  • 7
  • 7
  • 6
  • 6
  • 6
  • 5
  • 5
  • 5
  • 5
  • 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.
41

Optical Networking Technologies That Will Create Future Bandwidth-Abundant Networks [Invited]

Sato, Ken-ichi, Hasegawa, Hiroshi 07 1900 (has links)
No description available.
42

Analysis and Development of Fixed and Variable Waveband MUX/DEMUX Utilizing AWG Routing Functions

Kakehashi, Shoji, Hasegawa, Hiroshi, Sato, Ken-ichi, Moriwaki, Osamu, Kamei, Shin 01 January 2009 (has links)
No description available.
43

Optical MEMS Switches: Theory, Design, and Fabrication of a New Architecture

Basha, Mohamed 26 June 2007 (has links)
The scalability and cost of microelectromechanical systems (MEMS) optical switches are now the important factors driving the development of MEMS optical switches technology. The employment of MEMS in the design and fabrication of optical switches through the use of micromachining fabricated micromirrors expands the capability and integrity of optical backbone networks. The focus of this dissertation is on the design, fabrication, and implementation of a new type of MEMS optical switch that combines the advantages of both 2-D and 3-D MEMS switch architectures. This research presents a new digital MEMS switch architecture for 1×N and N×N optical switches. The architecture is based on a new microassembled smart 3-D rotating inclined micromirror (3DRIM). The 3DRIM is the key device in the new switch architectures. The 3DRIM was constructed through a microassembly process using a passive microgripper, key, and inter-lock (PMKIL) assembly system. An electrostatic micromotor was chosen as the actuator for the 3DRIM since it offers continuous rotation as well as small, precise step motions with excellent repeatability that can achieve repeatable alignment with minimum optical insertion loss between the input and output ports of the switch. In the first 3DRIM prototype, a 200×280 microns micromirror was assembled on the top of the electrostatic micromotor and was supported through two vertical support posts. The assembly technique was then modified so that the second prototype can support micromirrors with dimensions up to 400×400 microns. Both prototypes of the 3DRIM are rigid and stable during operation. Also, rotor pole shaping (RPS) design technique was introduced to optimally reshape the physical dimensions of the rotor pole in order to maximize the generated motive torque of the micromotor and minimize the required driving voltage signal. The targeted performance of the 3DRIM was achieved after several PolyMUMPs fabrication runs. The new switch architecture is neither 2-D nor 3-D. Since it is composed of two layers, it can be considered 2.5-D. The new switch overcomes many of the limitations of current traditional 2-D MEMS switches, such as limited scalability and large variations in the insertion loss across output ports. The 1×N MEMS switch fabric has the advantage of being digitally operated. It uses only one 3DRIM to switch the light signal from the input port to any output port. The symmetry employed in the switch design gives it the ability to incorporate a large number of output ports with uniform insertion losses over all output channels, which is not possible with any available 2-D or 3-D MEMS switch architectures. The second switch that employs the 3DRIM is an N×N optical cross-connect (OXC) switch. The design of an N×N OXC uses only 2N of the 3DRIM, which is significantly smaller than the N×N switching micromirrors used in 2-D MEMS architecture. The new N×N architecture is useful for a medium-sized OXC and is simpler than 3-D architecture. A natural extension of the 3DRIM will be to extend its application into more complex optical signal processing, i.e., wavelength-selective switch. A grating structures have been selected to explore the selectivity of the switch. For this reason, we proposed that the surface of the micromirror being replaced by a suitable gratings instead of the flat reflective surface. Thus, this research has developed a rigorous formulation of the electromagnetic scattered near-field from a general-shaped finite gratings in a perfect conducting plane. The formulation utilizes a Fourier-transform representation of the scattered field for the rapid convergence in the upper half-space and the staircase approximation to represent the field in the general-shaped groove. This method provides a solution for the scattered near-field from the groove and hence is considered an essential design tool for near-field manipulation in optical devices. Furthermore, it is applicable for multiple grooves with different profiles and different spacings. Each groove can be filled with an arbitrary material and can take any cross-sectional profile, yet the solution is rigorous because of the rigorous formulations of the fields in the upper-half space and the groove reigns. The efficient formulation of the coefficient matrix results in a banded-matrix form for an efficient and time-saving solution.
44

Optical MEMS Switches: Theory, Design, and Fabrication of a New Architecture

Basha, Mohamed 26 June 2007 (has links)
The scalability and cost of microelectromechanical systems (MEMS) optical switches are now the important factors driving the development of MEMS optical switches technology. The employment of MEMS in the design and fabrication of optical switches through the use of micromachining fabricated micromirrors expands the capability and integrity of optical backbone networks. The focus of this dissertation is on the design, fabrication, and implementation of a new type of MEMS optical switch that combines the advantages of both 2-D and 3-D MEMS switch architectures. This research presents a new digital MEMS switch architecture for 1×N and N×N optical switches. The architecture is based on a new microassembled smart 3-D rotating inclined micromirror (3DRIM). The 3DRIM is the key device in the new switch architectures. The 3DRIM was constructed through a microassembly process using a passive microgripper, key, and inter-lock (PMKIL) assembly system. An electrostatic micromotor was chosen as the actuator for the 3DRIM since it offers continuous rotation as well as small, precise step motions with excellent repeatability that can achieve repeatable alignment with minimum optical insertion loss between the input and output ports of the switch. In the first 3DRIM prototype, a 200×280 microns micromirror was assembled on the top of the electrostatic micromotor and was supported through two vertical support posts. The assembly technique was then modified so that the second prototype can support micromirrors with dimensions up to 400×400 microns. Both prototypes of the 3DRIM are rigid and stable during operation. Also, rotor pole shaping (RPS) design technique was introduced to optimally reshape the physical dimensions of the rotor pole in order to maximize the generated motive torque of the micromotor and minimize the required driving voltage signal. The targeted performance of the 3DRIM was achieved after several PolyMUMPs fabrication runs. The new switch architecture is neither 2-D nor 3-D. Since it is composed of two layers, it can be considered 2.5-D. The new switch overcomes many of the limitations of current traditional 2-D MEMS switches, such as limited scalability and large variations in the insertion loss across output ports. The 1×N MEMS switch fabric has the advantage of being digitally operated. It uses only one 3DRIM to switch the light signal from the input port to any output port. The symmetry employed in the switch design gives it the ability to incorporate a large number of output ports with uniform insertion losses over all output channels, which is not possible with any available 2-D or 3-D MEMS switch architectures. The second switch that employs the 3DRIM is an N×N optical cross-connect (OXC) switch. The design of an N×N OXC uses only 2N of the 3DRIM, which is significantly smaller than the N×N switching micromirrors used in 2-D MEMS architecture. The new N×N architecture is useful for a medium-sized OXC and is simpler than 3-D architecture. A natural extension of the 3DRIM will be to extend its application into more complex optical signal processing, i.e., wavelength-selective switch. A grating structures have been selected to explore the selectivity of the switch. For this reason, we proposed that the surface of the micromirror being replaced by a suitable gratings instead of the flat reflective surface. Thus, this research has developed a rigorous formulation of the electromagnetic scattered near-field from a general-shaped finite gratings in a perfect conducting plane. The formulation utilizes a Fourier-transform representation of the scattered field for the rapid convergence in the upper half-space and the staircase approximation to represent the field in the general-shaped groove. This method provides a solution for the scattered near-field from the groove and hence is considered an essential design tool for near-field manipulation in optical devices. Furthermore, it is applicable for multiple grooves with different profiles and different spacings. Each groove can be filled with an arbitrary material and can take any cross-sectional profile, yet the solution is rigorous because of the rigorous formulations of the fields in the upper-half space and the groove reigns. The efficient formulation of the coefficient matrix results in a banded-matrix form for an efficient and time-saving solution.
45

Mitteilungen des URZ 4/2008

Grunewald, Dietmar, Müller, Thomas, Richter, Frank, Riedel, Wolfgang, Schmidt, Ronald, Ziegler, Christoph 27 November 2008 (has links)
Informationen des Universitätsrechenzentrums
46

En studie i arbetssätt för distansstudier på högskola och universitet.

Lindgren, Oskar January 2010 (has links)
Den här rapporten undersöker distansutbildningar vid Högskolan i Kalmar, på Institutionen för kommunikation och design (IKD). Dels tas det upp hur IKD jobbar med distansstudier idag men även hur distansutbildning fungerar och hur man kan förbättra denna. Anledningen är att distansutbildningar idag är ett utvecklingsområde där det ständigt händer nya saker. Distansutbildning är kanske på väg att revolutionera sättet på vilket vi idag bedriver utbildning, både i grundskolan och upp till högskola/universitet. Uppdraget kommer från lärarna på IKD som känner att de vill förbättra sin situation. Undersökningen genomfördes med hjälp av etnografiska studier där undervisning observerades och lärare intervjuades. De etnografiska studierna jämfördes sedan med tidigare forskning inom ämnet. Därefter gjordes en marknadsundersökning för att se vilka program som fyller dagens behov. I slutändan resulterade projektet i ett antal program som hjälper lärarna i sitt arbete med distansstudier. Förutom de program som används idag föreslås även Adobe Acrobat Connect pro. Det är ett program som har köpts in av SUNET för att fungera som e-learning programvara för svenska högskolor och universitet. Dessutom bör Smartboarden som idag är installerad i flera salar användas i större utsträckning än idag. För synkron kommunikation används idag framförallt Skype mellan lärare och studenter. En ökad användning av Skype och/eller MSN skulle öka kommunikationen och samhörigheten mellan lärarna och studenterna ytterligare.
47

Traffic analysis of existing traffic in Kulyab region in order to plan and configure a new GSM MSC for this region / Trafikanalys av existerande trafik i Kulyab-regionen inför planering och konfigurering av en ny GSM MSC för denna region

Frostne, Isabel January 2011 (has links)
Wide area cellular mobile networks have rapidly evolved over the years. In the beginning achieving wide area coverage was a great achievement – enabling subscribers to call from wherever they were currently located and whenever they wanted. Additionally these systems supported mobility of subscribers, so that calls could continue even while a subscriber moved from one cell to another. Today mobility management is something everyone takes for granted. New functionality is continuously being developed for these networks. An important aspect of this evolution has been to enable new applications and technologies to be introduced while maintaining interoperability with the existing technologies. These mobile networks use new technologies and enable new applications, but they interconnect with existing networks that utilize earlier technologies, such as the existing fixed telephone network. These interconnections enable communication between subscribers connected via all of these networks. In today’s mobile networks there are a variety of technologies working side by side, for example 2G, GPRS, 3G, and so on. The earlier networks used circuit switching technology, but the trend in later networks was to transition exclusively to packet switching. One of the most important network entities is the mobile switch center (MSC). In the earlier circuit switched networks the MSC is the heart of the circuit switching network. The MSC is responsible for management, control, and communication to and from the mobile stations (MSs) in the area managed by the MSC. The MSC stores information about each of the MSs in one or more databases. In the subscriber’s home network the information about their subscription is stored in a home location register (HLR), while when this subscriber is in another network information is stored in a visitor location register (VLR). The MSC together with other elements of the core network handles mobility management, enabling both handover and roaming. A gateway MSC enables MSs to communicate with phones connected to the fixed network. The aim of this thesis is to analyze the traffic situation for Kulyab region in order to configure and install the MSC in Kulyab. For the time being there is no radio network controller (RNC) in Kulyab region, so the MSC in Kulyab will be configured to support 2G traffic. The configuration will be based on the expected mobile traffic load in the Kulyab region, thus the first steps in the process were to collect and analyze data about the existing traffic in this region that is currently served by a MSC located outside of this region. The configuration of the new MSC will be based on this analysis. After installing and configuring the new MSC some question need to be answered, namely: Can the MSC in Kulyab support all the base stations in Kulyab region? If not, how many base stations can it support? To what extent does the addition of this new MSC improve the overall network in terms of increased reliability, capacity, and throughput? How much will the capacity of the existing MSC, that is responsible for traffic outside Dushanbe, be increased due to the introduction of the new MSC? / Den mobila täckningen har utvecklats snabbt under åren. Att uppnå den mobila täckningen var i början en stor prestation – att kunna erbjuda telefontjänster för abonnenterna var än de befann sig och när de ville. Förutom detta så stödde detta system också fri rörlighet för abonnenterna. Under ett samtal kunde de förflytta sig från en cell till ett annan utan att samtalet bröts. Nu är mobilitetshanteringen någonting självklart. Nya funktioner utvecklas ständigt för dessa nätverk. En viktig aspekt för utvecklingen är att möjliggöra så att nya applikationer och teknologier kan introduceras och fortfarande vara kompatibla med de existerande teknikerna. Dessa mobilnätverk använder nya tekniker och möjliggör nya applikationer som är kompatibla med det existerande nätverket. Det existerande nätverket använder sig av tidigare teknologier, så som den fasta telefonnätet. Detta möjliggör kommunikation mellan abonnenterna från olika nätverk. I dagens nätverk finns det ett antal olika nätverk, som t.ex. 2G, GPRS, 3G och så vidare. Det tidigare nätverket använde sig av kretskopplad teknik, men trenden är attuteslutande använda sig av paketkopplad teknik. En av de viktigaste nätverksenheterna är ”Mobile switch center” (MSC). I de tidigare kretskopplade nätverket är MSC hjärtat i det kretskopplade nätverket. MSC är ansvarig för hanteringen, kontrollen och kommunikation till och från demobila enheterna (MS) i området som kontrolleras av MSCn. MSC lagrar information om var och en av MS i ett eller flera databaser. I abonnentens hemnätverk finns information om abonnentens abonnemang i ett hemregister (HLR). När abonnenten befinner sig i ett annat nätverk lagras informationen i ett gästregister (VLR). MSC hanterar mobilitet tillsammans med andra nätverksenheter i ”Core network” (CN) och möjliggör överlämnande (handover) och roaming. ”Gateway MSC” GMSC möjliggör kommunikation mellan MS och det fasta nätverket. Syftet med examensarbetet är att analysera trafiken för Kulyab-regionen för att konfigurera och installera en MSC i Kulyab. För tillfället finns ingen ”Radio network controller” (RNC) i regionen Kulyab, så MSCn i Kulyab kommer att konfigureras för att stödja 2G trafik. Konfigurationen baseras på den förväntade belastningen av mobiltrafiken i Kulyab-regionen, följaktligen är det första steget i processen att samla ihop och analysera information om den existerande trafiken i Kulyab-regionen. Trafiken tillhörande Kulyab-regionen handskas för närvarande av en MSC som befinner sig utanför detta område. Konfigurationen av den nya MSCn kommer att baseras på denna analys. Efter installationen och konfigurationen av den nya MSCn kommer följande frågor att bli besvarade, nämligen: Kan MSCn i Kulyab stödja alla basstationerna i Kulyab regionen? Om inte, hur många basstationer kan MSCn stödja? Till vilken grad kommer den nya MSCn att förbättra nätverket i termer av ökad tillförlitlighet, kapacitet och trafikgenomströmning? Hur mycket kommer kapacitetsökningen för den existerande MSC utanför Dushanbe att öka då MSC i Kulyab installeras?
48

Faculty Perceived Barriers of Online Education at a Midwestern University in Ohio

Fisher, Juenethia L. January 2020 (has links)
No description available.
49

金融帳開放與人民幣國際化:以滬港通為例 / The Liberalization of Financial Account and the Internationalization of the Renminbi: The Case of Shanghai - Hong Kong Stock Connect

林倩雯, Lin, Chien Wen Unknown Date (has links)
2008年發生全球金融危機,造成各國經濟大幅衰退。中國大陸於2009年開始積極推動人民幣國際化,希望降低對外貿易與跨境資本流動對美元的依賴程度。中國大陸雖有龐大的境外人民幣資金池,但由於欠缺人民幣回流管道,因而人民幣資金至今仍無法雙向流動。因此,中國大陸於2014年11月17日推動滬港通試點,建立滬港股票交易互聯互通機制,試行中國大陸金融帳開放成效,以作為日後擴大試點開放政策的參考。 本研究結果發現,經由滬港通試點試辦,改革中國大陸資本市場,可避免對中國大陸金融市場造成重大影響,實現人民幣跨境計價及結算功能,並建構良好的人民幣回流機制。 / The world economy declines substantially, influenced by the global financial crisis in 2008. In order to reduce the dependence of cross-border fund flows and foreign trades on the US dollar, the mainland China reinforces its efforts in promoting the Renminbi (RMB) internationalization in 2009. But, due to the capital control, the free fund flows of the RMB are not feasible even if there is a massive RMB pool worldwide. In order for the liberalization of financial account, the mainland China built Shanghai - Hong Kong Stock Connect on November 17, 2014, as a reference of further expansion of the offshore use of the RMB in the future. This study shows that, reforms on China’s domestic capital market are crucial to avoid the significant impact of Shanghai - Hong Kong Stock Connect, as the openness of capital account, on the domestic financial markets. The financial reforms can also improve the cross-border settlement functions of the RMB to increase RMB denomination in trades, and reinforce the freer flows of the RMB.
50

企業生命週期與經營策略關係之探討

王銘宏, WANG, MING-HONG Unknown Date (has links)
本論文共一冊,約有四萬餘字,分六章廿四節。 第一章導論說明本研究的問題及目的,建立之架構。第二章文獻探討,首先個別探討 生命週期及經營策略之文獻內容及研究方法,然後加以整合。第三章為研究方法,說 明本文為一縱貫式調查之描述性研究,並界定變數之操作定義。第四章企業生命週期 與經營策略演變之關係,先作我國企業生命週期之分析,再驗證其採用之經營策略。 第五章績優與績劣企業經營策略之探討,查驗不同績效之企業,其策略之差異及其影 響因素。第六章結論,提出本論文實證結果,並加以說明

Page generated in 0.0413 seconds