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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.
131

PROTOPLANETARY AND TRANSITIONAL DISKS IN THE OPEN STELLAR CLUSTER IC 2395

Balog, Zoltan, Siegler, Nick, Rieke, G. H., Kiss, L. L., Muzerolle, James, Gutermuth, R. A., Bell, Cameron P. M., Vinkó, J., Su, K. Y. L., Young, E. T., Gáspár, András 18 November 2016 (has links)
We present new deep UBVRI images and high-resolution multi-object optical spectroscopy of the young (similar to 6-10 Myr old), relatively nearby (800 pc) open cluster IC 2395. We identify nearly 300 cluster members and use the photometry to estimate their spectral types, which extend from early B to middle M. We also present an infrared imaging survey of the central region using the IRAC and MIPS instruments on board the Spitzer Space Telescope, covering the wavelength range from 3.6 to 24 mu m. Our infrared observations allow us to detect dust in circumstellar disks originating over a typical range of radii from similar to 0.1 to similar to 10 au from the central star. We identify 18 Class II, 8 transitional disk, and 23 debris disk candidates, respectively, 6.5%, 2.9%, and 8.3% of the cluster members with appropriate data. We apply the same criteria for transitional disk identification to 19 other stellar clusters and associations spanning ages from similar to 1 to similar to 18 Myr. We find that the number of disks in the transitional phase as a fraction of the total with strong 24 mu m excesses ([8] - [24]. 1.5) increases from (8.4. +/- 1.3)% at similar to 3 Myr to (46. +/- 5)% at similar to 10 Myr. Alternative definitions of transitional disks will yield different percentages but should show the same trend.
132

半導體設備測試廠商競爭策略之研究-外商在大陸之個案 / SemiTest equipment supplier competitive strategy in China : the case of a foreign firm

王緯杰, Wang, Wei Chieh Unknown Date (has links)
中國的半導體產業發展早在2000年初即由中國的半導體之父-張汝京先生創立了中芯國際半導體公司(SMIC),得到中國政府的全力支持,展開風起雲湧的半導體運動。張汝京積極的在大陸複製台灣晶圓代工模式,中國政府亦寄望於他,希望能將台灣成功的半導體產業能落實、深根至大陸。然則歷經十年的產業發展,其製程技術一直無法突破,以進入先進製程之林,也因此大陸半導體產業鏈(含封裝、測試)一直停滯、落後於台灣,只能代工技術門檻低、毛利低的晶片生產、封裝與測試。 然中國政府自金融海嘯後,改變策略,大力培植IC設計公司,從更上游始,利用台灣成熟、先進的代工技術,培養、落實在地化IC設計團隊以影響半導體產業的發展。實至今日,大陸已有超過1000家以上的設計公司投入到整個中國半導體市場、並打進全球供應鏈。兩岸半導體產業結構已悄悄的在慢慢改變中。 以本研究的T公司(個案公司)而言,為全球首屈一指的半導體專業測試商,其專業於微波通訊、數位行動、基頻、電源管理與記憶體晶片,….等等之測試,以完整的配套測試方案之整合,迅速成為全球各地的IC設計製造廠商與代工廠在晶片測試領域的重要夥伴。然而在逐漸起飛,研發實力漸增的大陸市場中,T公司卻發生了業務拓展上的問題與瓶頸。公司內部擁有的能力與價值,是公司發展和擬定策略的基礎,且是公司利潤的來源,因此如何利用公司產品的優勢、組織內部資源與能力,以提出適合于中國市場的方案策略,成為中國在地公司的「策略夥伴」是公司再創盈利與提升全球市占率的一大課題。
133

Razvoj metoda dijagnostike usisnog sistema motora sa unutrašnjim sagorevanjem / Development of an IC Engine Intake Air Path Fault Diagnosis Method

Nikolić Nebojša 03 July 2015 (has links)
<p style="text-align: justify;">U radu je razvijen jedan matematički model za simuliranje ponašanja nekih važnih radnih parametara motora SUS, kada u njegovom usisnom sistemu postoje neispravnosti tipa: &bdquo;nepredviđeni ulaz vazduha u usisni kolektor&ldquo;, &bdquo;pogrešno očitavanje senzora masenog protoka vazduha&ldquo;, &bdquo;pogrešno očitavanje senzora pritiska u usisnom kolektoru&ldquo;, &bdquo;pogrešno očitavanje senzora temperature u usisnom kolektoru&ldquo; i &bdquo;umanjen EGR protok&ldquo;. Na osnovu rezultata ovog modela predložen je novi dijagnostički koncept, u okviru kojeg je razvijen jedan model za prepoznavanje pomenutih neispravnosti. Predloženi koncept je proveren na realnim podacima, prikupljenim ispitivanjem jednog stvarnog motora u laboratorijskim uslovima, pri čemu su dobijeni zadovoljavajući rezultati.</p> / <p>A mathematical model capable of simulating some important IC engine operating parameters behavior when a fault in its intake air path exists. The faults considered are of the following types: &bdquo;air leakage in the intake path&ldquo;, &bdquo;faulty mass air flow sensor&ldquo;, &bdquo;faulty manifold absolute pressure sensor&ldquo;, &bdquo;faulty intake air temperature sensor&ldquo; and &bdquo;clogged EGR pipe&ldquo;. Relying on the data obtained by the fault simulator, a novel diagnosis concept is proposed. A model for fault detection and diagnosis was developed in the scope of the concept. The proposed concept was tested on the real data collected from an automobile IC engine in the laboratory conditions and satisfying results were obtained.</p>
134

Indirect Analog / RF IC Testing : Confidence & Robusteness improvments / Test Indirect des circuits analogique et RF : Contribution pour une meilleur précision et robustesse

Ayari, Haithem 12 December 2013 (has links)
The conventional approach for testing RF circuits is specification-based testing, which involves verifying sequentially all specification requirements that are promised in the data sheet. This approach is a long-time effective testapproach but nowadays suffers from significant drawbacks.First, it requires generation and capture of test signals at the DUT operating frequency. As the operational frequencies of DUT are increasing, it becomes difficult to manage signal generation and capture using ATE. As a consequence, there is a need of expensive and specialized equipment. In addition,as conventional tests target several parameters, there is a need of several data captures and multiple test configurations. As a consequence, by adding settling time between each test and test application time, the whole test time becomes very long, and the test board very complex. Another challenge regarding RF circuit testing is wafer-level testing. Indeed, the implementation of specification-based tests at wafer level is extremely difficult due to probing issues and high parasitic effects on the test interface.Moreover, multi-site testing is usually not an option due to the small count of available RF test resources, which decreases test throughput. Hence, the current practice is often to verify the device specifications only after packaging.The problem with this solution is that defective dies are identified late in the manufacturing flow, which leads to packaging loss and decreases the global yield of the process.In order to reduce production costs, there is therefore a need to develop test solutions applicable at wafer level, so that faulty circuits can be removed very early in the production flow. This is particularly important for dies designed to be integrated in Systems-In-Package (SIP).In this context, a promising solution is to develop indirect test methods. Basically, it consists in using DUT signatures to non-conventional stimuli to predict the result of conventional tests. The underlying idea is to learn during an initial phase the unknown dependency between simple measurements and conventional tests. This dependency can then be modeled through regression functions. During the testing phase, only the indirect measurements are performed and specifications are predicted using the regression model built in the learning phase.Our work has been focused on two main directions. First, we have explored the implementation of the alternate test method based on DC measurements for RF circuits and we have proposed a methodology to select the most appropriateset of DC parameters. Results from two test vehicles (a LNA using electrical simulations and a PA using real production data) indicate that the proposed methodology allows precise estimation of the DUT performances while minimizing the number of DC measurements to be carried out.Second, we have proposed a novel implementation of the alternate test strategy in order to improve confidence in alternate test predictions and to overcome the effect of limited training set sizes. The idea is to exploit model redundancy in order to identify, during the production testing phase, devices with suspect predictions; these devices are then are removed from the alternate test tierand directed to a second tier where further testing may apply. / The conventional approach for testing RF circuits is specification-based testing, which involves verifying sequentially all specification requirements that are promised in the data sheet. This approach is a long-time effective testapproach but nowadays suffers from significant drawbacks.First, it requires generation and capture of test signals at the DUT operating frequency. As the operational frequencies of DUT are increasing, it becomes difficult to manage signal generation and capture using ATE. As a consequence, there is a need of expensive and specialized equipment. In addition,as conventional tests target several parameters, there is a need of several data captures and multiple test configurations. As a consequence, by adding settling time between each test and test application time, the whole test time becomes very long, and the test board very complex.Another challenge regarding RF circuit testing is wafer-level testing. Indeed, the implementation of specification-based tests at wafer level is extremely difficult due to probing issues and high parasitic effects on the test interface.Moreover, multi-site testing is usually not an option due to the small count of available RF test resources, which decreases test throughput. Hence, the current practice is often to verify the device specifications only after packaging.The problem with this solution is that defective dies are identified late in the manufacturing flow, which leads to packaging loss and decreases the global yield of the process.In order to reduce production costs, there is therefore a need to develop test solutions applicable at wafer level, so that faulty circuits can be removed very early in the production flow. This is particularly important for dies designed to be integrated in Systems-In-Package (SIP).In this context, a promising solution is to develop indirect test methods. Basically, it consists in using DUT signatures to non-conventional stimuli to predict the result of conventional tests. The underlying idea is to learn during an initial phase the unknown dependency between simple measurements and conventional tests. This dependency can then be modeled through regression functions. During the testing phase, only the indirect measurements are performed and specifications are predicted using the regression model built in the learning phase.Our work has been focused on two main directions. First, we have explored the implementation of the alternate test method based on DC measurements for RF circuits and we have proposed a methodology to select the most appropriateset of DC parameters. Results from two test vehicles (a LNA using electrical simulations and a PA using real production data) indicate that the proposed methodology allows precise estimation of the DUT performances while minimizing the number of DC measurements to be carried out.Second, we have proposed a novel implementation of the alternate test strategy in order to improve confidence in alternate test predictions and to overcome the effect of limited training set sizes. The idea is to exploit model redundancy in order to identify, during the production testing phase, devices with suspect predictions; these devices are then are removed from the alternate test tierand directed to a second tier where further testing may apply.
135

Simulation of turbulent flames at conditions related to IC engines

Ghiasi, Golnoush January 2018 (has links)
Engine manufacturers are constantly seeking avenues to build cleaner and more ef cient engines to meet ever increasing stringent emission legislations. This requires a closer under- standing of the in-cylinder physical and chemical processes, which can be obtained either through experiments or simulations. The advent of computational hardware, methodologies and modelling approaches in recent times make computational uid dynamics (CFD) an important and cost-effective tool for gathering required insights on the in-cylinder ow, combustion and their interactions. Traditional Reynolds-Averaged Navier-Stokes (RANS) methods and emerging Large Eddy Simulation (LES) techniques are being used as a reli- able mathematical framework tools for the prediction of turbulent ow in such conditions. Nonetheless, the combustion submodels commonly used in combustion calculations are developed using insights and results obtained for atmospheric conditions. However, The combustion characteristics and its interaction with turbulence at Internal combustion (IC) engine conditions with, high pressure and temperatures can be quite different from those in conventional conditions and are yet to be investigated in detail. The objective here is to apply FlaRe (Flamelets revised for physical consistencies) model for IC engines conditions and assess its performance. This model was developed in earlier studies for continuous combustion systems. It is well accepted that the laminar burning velocity, SL, is an essential parameter to determine the fuel burn rate and consequently the power output and ef ciency of IC engines. Also, it is involved in almost all of the sophisticated turbulent combustion models for premixed and partially premixed charges. The burning velocities of these mixtures at temperatures of 850 ≤ T ≤ 950 decrease with pressure up to about 3 MPa as it is well known, but it starts to increase beyond this pressure. This contrasting behaviour observed for the rst time is explained and it is related to the role of pressure dependent reaction for iso-octane and involving OH and the in uence of this radical on the fuel consumption rate. The results iv seem to suggest that the overall order of the combustion reaction for iso-octane and gasoline mixture with air is larger than 2 at pressures higher than 3 MPa. The FlaRe combustion is used to simulate premixed combustion inside a spark-ignition engine. The predictive capabilities of the proposed approach and sensitivity of the model to various parameters have been studied. FlaRe approach includes a parameter βc representing the effects of ame curvature on the burning rate. Since the reactant temperature and pressure inside the cylinder are continually varying with time, the mutual in uence of ame curvature and thermo-chemical activities may be stronger in IC engines and thus this parameter is less likely to be constant. The sensitivity of engine simulation results to this parameter is investigated for a range of engine speed and load conditions. The results indicate some sensitivity and so a careful calibration of this parameter is required for URANS calculation which can be avoided using dynamic evaluations for LES. The predicted pressure variations show fair agreement with those obtained using the level-set approach. DNS data of a hydrogen air turbulent premixed ame in a rectangular constant volume vessel has been analysed to see the effect of higher pressure and temperature on the curvature parameter βc. Since the reactant temperature and pressure inside the cylinder are continually varying with time, the mutual in uence of ame curvature and thermo-chemical activities are expected to be stronger in IC engines and thus the parameter βc may not be constant. To shed more light on this, two time steps from the DNS data has been analysed using dynamic βc procedure. The results show that the effect of higher pressure and temperature need to be considered and taken into account while evaluating βc. When combustion takes place inside a closed vessel as in an IC engine the compression of the un-burnt gases by the propagating ame causes the pressure to rise. In the nal part of this thesis, the FlaRe combustion model is implemented in a commercial computational uid dynamics (CFD) code, STAR-CD, in the LES framework to study swirling combustion inside a closed vessel. Different values of βc has been tested and the need for dynamic evaluation is observed.
136

Distribuição de luminosidade em galáxias espirais barradas

Saraiva, Maria de Fátima Oliveira January 1992 (has links)
Estudamos, através de fotometria superficial CCD em B, V, R e I, quatro galáxias espirais, classificadas como barradas, com tipos morfológicos entre Sa e Se: NGC 6835, NGC 5757, IC 1091 e NGC 7412. Para cada galáxia, obtivemos mapas de isofotas e, através do ajuste de elipses às isofotas, determinamos parâmetros como inclinação, orientação no céu e diâmetros. Pelo ajuste de curvas padrões de crescimento às magnitudes integradas, obtivemos magnitudes totais em B e V. Traçamos diferentes tipos de perfis de brilho, tais como perfis de luminosidade ao longo dos eixos maior e menor das galáxias e/ou das barras, perfis de luminosidade promediados elipticamente e perfis azimutais. Os perfis nas direções das barras mostraram que o brilho superficial ao longo dessas componentes decresce de maneira uniforme, com um gradiente quase exponencial, e que é mais íngreme em I do que em B. Decompusemos os perfis de luminosidade médios em componentes bojo e disco, ajustando leis de De Vaucouleurs e exponencial. Os perfis azimutais foram estudados com análise de Fourier para determinar as componentes dominantes na região da barra. Traçamos perfis em várias cores ao longo dos eixos principais das galáxias e constatamos que três delas têm núcleo azul, sugerindo ser esse um fenômeno comum em galáxias barradas. Comparamos as cores nucleares com modelos de síntese de população estelar, o que mostrou que aconteceram eventos de formação estelar nesses núcleos nos últimos 108 anos. / We obtained CCD surface photometry in the B, V, R, I wavebands, for four barred spiral galaxies with morphological types ranging from Sa to Se: NGC 6835, NGC 5757, IC 1091, and NGC 7412. For each galaxy we obtained isophote maps, inclination, orientatión, and diameters. We determined B and V total magnitudes by fitting standard growth curves to integrated magnitudes. We determined different kinds of luminosity profiles, · such as luminosity profiles along the major and minor axis of the galaxies and/or the bars, elliptically averaged luminosity profiles and azimuthal profiles. The profiles along the major axis of the bars showed that the surface brightness along these components decreases smoothly; the gradient is almost exponential and steeper in I than in B. We decomposed the mean luminosity profiles in contributions from bulge and disc, using as fitting functions de Vaucouleurs' law and an exponentiallaw. The azimuthal profiles were studied by Fourier transformations to determine the main components in the bar region. Color profiles along the principal axis of the galaxies revealed that three of them have blue nucleus, suggesting · this is a common phenomenon among barred galaxies. A comparison of the nuclear colors with models of stellar population synthesis showed that bursts of star formation occurred in these nuclei during the last 108 years.
137

產業合作網路與知識流通之研究--以IC製造業為例

謝甄珮 Unknown Date (has links)
IC產業的蓬勃發展,已成為臺灣的明星產業,該產業的另一項特色是分工細膩,因而形成緊密的合作綱路,藉著這樣的綱路合作關係,知識在產業合作成員間流通,進而形成IC產業創新的一個主要因素。 由於IC製造業身處IC產業的中心位置,因此本研究以IC製造業為研究對象,選取三家公司作為樣本,探討個案公司與設備商、晶圓材料商、IDM公司、IC設計業、光罩製造商和IC封裝廠的關係,以及有哪些知識經由這樣的合作關係,由綱路成員流通到個案公司,進一步造成個案公司的組織知識創新。 研究發現如下: 1. 合作產業與組織產業的技術相關性會影響組織與合作成員的綱路關係強度。當合作成員的產業與組織產業的「技術相關性」越高時,組織與合作面員間的互動程度越高。 2. 組織的經營策略會影響組織與合作成員的綱路關係強度。當組織的「公司經營策略」為專業代工製造、製程技術領先者時,組織與合作成員間的綱路關係形式,偏向為正式契約及非正式結盟關係。當組織的「公司經營策略」為產品整合製造、製程技術追隨者時,組織與合作成員間的綱路關係形式,偏向為買賣關係。 3. 在IC產業中,組織若居於技術領導者的地位,其綱路成員大多也是該產業的領導者。 4. 組織與合作成員的知識流通介面,與合作面員產業與組織產業的技術相關程度有關。 5. 組織與合作成員流通的知識內涵,與組織和合作成員的綱路強度有關。 6. 當組織和合作成員的綱路強度越強時,組織與合作成員流通的知識才有內隱性的知識。 7. 組織與合作成員間的知識流通,有助於組織知識創造。組織與成員間知識流通內涵越豐富,越有助於組織知識創造。組織與成員間知識流通的特性越是內隱性知識,越有助於組織知識創造。 8. 我國IC製造產業透過產業合作的綱路關係,由合作成員的知識流通,產生知識創造,進而提升IC製造業的製程能力,甚至超越合作夥伴。
138

The Importance of Intellectual Capital for the Entrepreneurial Firm

Vazquez, Francisco, Michalski, Markus January 2008 (has links)
<p>Entrepreneurship and Intellectual Capital (IC) have become important concepts for economies around the world over the last decades, even though, due to their multidisciplinary nature, different definitions have been developed concerning these concepts. There are some authors who regard these phenomena as being in strong opposition to traditional theories, such as economics, accounting, finance, to mention a few, but they have played a vital role for a better understanding of the success and/or failure of firms. In this paper we are going to address the factors influencing the success of the entrepreneurial firm, focusing on IC and the entrepreneur as the main contributors to this outcome. A theoretical model of analysis is presented illustrating how entrepreneurs utilize IC to lead firms towards success, which at the same time contributes back to the experience of the entrepreneur. The model will then be tested by applying it on BPM (Bau- & Projektmanagement GmbH), a German project management firm founded by Peter Christa that specializes in administrating small, medium, and large public construction projects, especially in the field of hospital redevelopment and expansion.</p>
139

Rapportering av intellektuellt kapital : i Sveriges fyra största banker.

Succo, Victor, Jonsson Ek, Ida January 2009 (has links)
<p>Den här studien har haft som avsikt att undersöka hur redovisning av intellektuellt kapital rapporteras av de fyra största bankerna i Sverige. Vi beskriver och analyserar vilka indikatorer bankerna fokuserar på i redovisningen av intellektuellt kapital. Vi har gjort en kvalitativ undersökning genom att analysera den icke-finansiella delen i årsredovisningar från Handelsbanken, SEB, Swedbank och Nordea från åren 1998, 2003 och 2008. Vi har valt att kategorisera intellektuellt kapital efter MERITUM’s definitioner av human-, struktur- och relationskapital. Resultatet av studien visar att redovisningen inte följer någon enhetlig standard för redovisning av intellektuellt kapital. Det presenteras mycket information men fokuseringen ligger på enstaka indikatorer. Detta gör att redovisningen blir svår att jämföra. Studien visar att bankerna fokuserar mest på indikatorerna kompetensutveckling, rutiner, policies, företagskultur och kundrelationer.</p>
140

The Importance of Intellectual Capital for the Entrepreneurial Firm

Vazquez, Francisco, Michalski, Markus January 2008 (has links)
Entrepreneurship and Intellectual Capital (IC) have become important concepts for economies around the world over the last decades, even though, due to their multidisciplinary nature, different definitions have been developed concerning these concepts. There are some authors who regard these phenomena as being in strong opposition to traditional theories, such as economics, accounting, finance, to mention a few, but they have played a vital role for a better understanding of the success and/or failure of firms. In this paper we are going to address the factors influencing the success of the entrepreneurial firm, focusing on IC and the entrepreneur as the main contributors to this outcome. A theoretical model of analysis is presented illustrating how entrepreneurs utilize IC to lead firms towards success, which at the same time contributes back to the experience of the entrepreneur. The model will then be tested by applying it on BPM (Bau- &amp; Projektmanagement GmbH), a German project management firm founded by Peter Christa that specializes in administrating small, medium, and large public construction projects, especially in the field of hospital redevelopment and expansion.

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