On 29th February 2000, The Directorate General of Telecommunications, Ministry of Transportation and Communications, announced the result of selection for DAB (Digital Audio Broadcasting) experimental digital broadcasting. From that moment, many FM Radio Stations initiated their DAB digital broadcasting. Compared with FM Radio, AM Radio is slower on initiating digital broadcasting. However, new technology continuously comes out. The integration of media technology has a great influence on the media broadcasting model. The emergence of new media accelerates the decline of traditional media. Earlier emerging than internet, TV and FM Radio industries, how will AM Radio strive for continuance and development? To encourage existing AM Radio in initiating their digital future, the Ministry of Transportation and Communications announced the project of experimental digital broadcasting of IBOC AM and DRM on June 3rd, 2004. It is worth for the research scholars to study how the AM Radio initiates digital broadcasting and what the influential factors are. Therefore, this research is trying to find the factors which turn AM Radio to the digital future, and also discuss what factors will encourage radio enterprenors to initiate digital broadcasting, what kind of digital system is appropriate for AM Radio, and what the situation is for experimental DRM broadcasting in Taiwan. We are trying to find out the factors turning AM Radio to the digital future, and make AM Radio (with declining listening ratio and poor reception quality) improve the performance, as well as create new core value of AM Radio Industry. According to the objective and motivation above-mentioned, we designed and proceeded this research as follows: We started from an investigation on 28 AM Radio Stations in Taiwan to know their needs for digital broadcasting, and then collected data and made statistic analysis based on the questionnaires returned. We also took interviews with professional people assisting in DRM digital broadcasting for AM Radio. Besides, we participated in the World DAB Forum Conference held in Taiwan in this year, and finally went into a conclusion and some suggestions. We found from the information in questionnaires that the factors making AM Radio to initiate digital broadcasting are not precise. However, we know more about how the digital broadcasting is going among AM Radio Stations, from the information collected by interviewing professional people who assist in DRM digital broadcasting for AM Radio. It will bring advantages in competition for AM Radio Stations to initiate digital broadcasting. Thus, it can not wait to turn to digital future. The Radio enterprenors should use technology well and increase additional value. They have to follow the trend, develop new co-operation model, and establish their brand image. They should also enhance on inspection of program contents, and hold success factors. They can increase reception ratio only with fine broadcasting, excellent program contents, good reception quality and perfect marketing strategy. As to the technical people, they need to care about the development on technology, and provide new information for management to make decision. Besides, the policy of government must be precise, in order to encourage Radio enterprenors in initiating digital broadcasting. The above conclusion could be the reference in digital radio research.

Wire mesh vibration dampers have been the subject of some very encouraging experiments at the Texas A&M Turbomachinery laboratories for the past several years and have emerged as an excellent replacement for squeeze film dampers. Their capability to provide damping for a wide range of temperatures (even cryogenic), fluid free operation and ability to perform even when soaked with lubricants makes them a suitable option as a bearing damper. Experiments were conducted to investigate the effect of design parameters like axial thickness and axial compression that influence the characteristics of wire mesh as a bearing damper. Two groups of wire mesh were tested to show that the stiffness and damping are directly proportional to the axial thickness, if all the other parameters are kept constant. Tests on four wire mesh donuts of different radial thickness showed that stiffness and damping vary inversely with radial thickness. Rigorous tests were also conducted to quantify the effects of axial compression, radial interference and displacement amplitude on stiffness and damping of the wire mesh. Another novel kind of mesh damper tested was comprised of two small segments instead of a whole donut. The results showed that wire mesh exhibited good damping characteristics even when used in small segments. Empirical expressions were developed using MathCADTM worksheets, and an existing ExcelTM design worksheet was modified to include these factors. The effect of frequency variation was also included to give a comprehensive design tool for wire mesh. A new design worksheet was developed that can predict rotordynamic coefficients for a wire mesh bearing damper having a different size as well as different installation and operational conditions.

This thesis investigates both theoretical and implementation-level aspects of switching- feedback control strategies for the development of voltage-controlled oscillators. We use a modified sliding-mode compensation scheme based on various norms of the system state to achieve amplitude control for wide-tuning range oscillators. The proposed controller provides amplitude control at minimal cost in area and power consumption. Verification of our theory is achieved with the physical realization of an amplitude controlled negative-Gm LC oscillator. A wide-tuning range RF ring oscillator is developed and simulated, showing the effectiveness of our methods for high speed oscillators. The resulting ring oscillator produces an amplitude controlled sinusoidal signal operating at frequencies ranging from 170 MHz to 2.1 GHz. Total harmonic distortion is maintained below 0:8% for an oscillation amplitude of 2 Vpp over the entire tuning range. Phase noise is measured as -105.6 dBc/Hz at 1.135 GHz with a 1 MHz offset.

<p>Detta examensarbete utröner möjligheten att aktivt släcka ut en amplitudstark frekvensmodulerad sinussignal digitalt. Detta skall göras utan förkunskap om signalen gällande fas, frekvens eller amplitud. Eventuellt övriga, men betydligt svagare, sinussignaler i den analoga signalen skall inte påverkas nämnvärt av utsläckningen. För att lösa problemet har olika teorier för att lösa delproblemen med att mäta amplitud, fas och frekvens studerats varefter en lämplig kombination valts för implementering i en FPGA. Prestandan som uppmätts har jämförts med vad som teoretiskt är möjligt och vi konstaterar att metoden löser problemet på ett adekvat sätt men är i behov av en del förbättringar som diskuteras i slutet.</p> / <p>This master thesis investigates the possibility to cancel a frequency modulated sinusoid with high amplitude in the digital domain. This will be done without any pre-knowledge of the signal regarding phase, frequency or amplitude. Other arbitrary, but weaker, sinusoids present in the analog signal should not be noticeable affected by the cancellation. To solve the partial problems of measuring amplitude, frequency and phase, different theories have been studied and thereafter a suitable combination was chosen for implementation in a Field Programmable Gate Array, FPGA. The performance measured has been compared to the theoretical maximum performance and it has been concluded that the proposed implementation solves this problem adequately but needs some enhancements, these are discussed in the final chapter.</p>

Tez (Yüksek Lisans) - Süleyman Demirel Üniversitesi, Fen Bilimleri Enstitüsü, Jeofizik Mühendisliği Anabilim Dalı, 2008. / Kaynakça var.

The Woodford Shale formation is currently an important unconventional gas resource that extends across parts of the mid-continent of the United States. A resource shale acts as source, seal, and reservoir, and its characterization is vital to successful exploitation and production of hydrocarbons. This work is a surface seismic observation and investigation of the seismic anisotropy present in the Woodford Shale formation in the Anadarko Basin, Oklahoma. One of the main causes of anisotropy here is commonly believed to be vertical natural fractures (HTI) and horizontal alignment of clay minerals (VTI). Understanding the natural fracture orientation and density, as well as regional stress orientation, is important to the development of hydraulic fracturing programs in shales, such as the Woodford, producing natural gas. Dipole sonic log measurements in vertical boreholes suggest that the Woodford does possess vertical transverse isotropy (VTI), due possibly to horizontal layering or aligned clay minerals. Further, the borehole logs do not indicate horizontal transverse isotropy (HTI) associated with fracturing in the Woodford interval. An amplitude varying with angle and azimuth (AVAZ) analysis was applied to 3-D surface seismic data in the Anadarko Basin and shows the dipole sonic logs may not be completely characterizing the anisotropy observed in the Woodford. Once this apparent contradiction was discovered, additional work to characterize the fractures in the formation was undertaken. A petrophysical model based on the borehole data of the Woodford Shale was created, combining various techniques to simulate the rock properties and behavior. With a more complete rock physics model, a full stiffness tensor for the rock was obtained. From this model, synthetic seismic data were generated to compare to the field data. Furthermore, analytic equations were developed to relate crack density to AVAZ response. Currently, the application of this AVAZ method shows fracture orientation and relative variations in fracture density over the survey area. This work shows a direction for a quantified fracture density because the synthetic seismic data has a quantified fracture density at its basis. This allowed for a relationship to be established between explicit fracture parameters (such as fracture density) and AVAZ results and subsequently may be used to create regional descriptions of fracture and/or stress orientation and density. / text

I conducted an amplitude vs. offset (AVO) analysis on newly acquired 3D seismic reflection data to detect elevated pore fluid content and pore fluid pressure along the Costa Rica convergent margin to address dewatering processes of subduction zone sediments. These data provide the highest quality 3D seismic data acquired to date along a convergent margin for detailed analysis of geophysical properties along the plate boundary fault interface. In 2011, a 55 km by 11 km 3D seismic reflection survey was completed using the R/V Marcus G. Langseth offshore western Costa Rica at the convergent margin of the Cocos and Caribbean plates. We applied pre-stack Kirchhoff time migration to a subset of these data across the frontal prism where amplitude versus offset (AVO) attributes were extracted along the decollement. When pore fluid pressure, l , exceeds 0.7, the pressure at which Poisson’s ratio begins to approach that of water, the AVO response of a fluid-filled, clay-rich decollement requires a high Poisson’s ratio and an excessively low seismic P-wave and S-wave velocity. Acute wedge taper, undercompacted subducted hemipelagic and pelagic sediments, and a smooth decollement in the northwest half of the survey correspond with decollement AVO response of relatively high values of Poisson’s ratio. These findings suggest increased pore fluid content and vertical containment of near-lithostatic pore fluid pressures within the decollement. In contrast, increased wedge taper angles, thin hemipelagic and pelagic sediments, and a rugose decollement beneath the southeastern frontal prism produce an AVO response interpreted as due to lower pore fluid contents and pressures. We propose that large-offset subducting basement normal faults in this area, as close as 20 m from the decollement, induce vertical fractures within the decollement that allow for fluid expulsion into the frontal prism and lower fluid pressure. Lateral variability of overpressure within the decollement shear zone of subduction margins is important in understanding the evolution of frontal prism strain accumulation and seismogenic rupture. / text

Detta examensarbete utröner möjligheten att aktivt släcka ut en amplitudstark frekvensmodulerad sinussignal digitalt. Detta skall göras utan förkunskap om signalen gällande fas, frekvens eller amplitud. Eventuellt övriga, men betydligt svagare, sinussignaler i den analoga signalen skall inte påverkas nämnvärt av utsläckningen. För att lösa problemet har olika teorier för att lösa delproblemen med att mäta amplitud, fas och frekvens studerats varefter en lämplig kombination valts för implementering i en FPGA. Prestandan som uppmätts har jämförts med vad som teoretiskt är möjligt och vi konstaterar att metoden löser problemet på ett adekvat sätt men är i behov av en del förbättringar som diskuteras i slutet. / This master thesis investigates the possibility to cancel a frequency modulated sinusoid with high amplitude in the digital domain. This will be done without any pre-knowledge of the signal regarding phase, frequency or amplitude. Other arbitrary, but weaker, sinusoids present in the analog signal should not be noticeable affected by the cancellation. To solve the partial problems of measuring amplitude, frequency and phase, different theories have been studied and thereafter a suitable combination was chosen for implementation in a Field Programmable Gate Array, FPGA. The performance measured has been compared to the theoretical maximum performance and it has been concluded that the proposed implementation solves this problem adequately but needs some enhancements, these are discussed in the final chapter.

Magistro baigiamąjį darbą sudaro 57 puslapiai. Jame yra 8 lentelės, 31 paveikslėliai, 44 literatūros šaltiniai ir 13 priedų. Magistro darbe tiriama antropogeninio poveikio įtaka Vidzgirio botaninio draustinio retiems augalams. Darbo objektas- reti augalai augantys Vidzgirio botaninio draustinio teritorijoje. Darbo tikslas- įvertinti retų augalų dinamiką per pastaruosius metus ir ieškoti priemonių jų išlikimui. Darbo metodai- retų augalų gausumui nustatyti naudojomės Botanikos instituto parengta monitoringo metodika (Parengta Zigmanto Gudžinsko 2001 m. Botanikos institutas, Floros ir geobotanikos laboratorija). Aprašant augavietę kiekvienos rūšies augalų gausumas ir padengimas vertinami balais pagal Braun- Blanquet skalę . Atlikus tyrimus ir įvertinus retų augalų paplitimą nustatyta, kad 7 iš 11 rastų retų augalų auga antropogeninio poveikio zonoje Jų augavietės yra šalia upelio, piliakalnio ir mokomojo tako. Šios vietos yra gausiai lankomos. Reti augalai augantys Vidzgirio botaniniame draustinyje nukenčia nuo intensyvios rekreacijos, kirtimų, šiukšlių. Tyrimų metu nustatyta, kad sumažėjo tamsialapio skiautalūpio individų skaičius. Pagausėjo plačialapės klumpaitės individų skaičius. Rastos naujos retų augalų augavietės. Norint užtikrinti saugomų augalų augaviečių stabilumą, ypač vertinguose miško sklypuose reikia taikyti tokį patį ūkininkavimo režimą, kaip I grupės miškuose, visoje draustinio teritorijoje vengti bet kokių introdukuotų augalų rūšių sodinimo, sureguliuoti... [toliau žr. visą tekstą] / Final master degree work of University, 57 pages, 31 figures, 8 tables, 36 references, 44 appendix. Master degree work cover the studies of antropogenic effect to the rare plants, which are growing in the botanical conservation area of Vidzgiris. The object of research- rare plants growing in conservation area of Vidzgiris. The aim of research- to evaluate dynamic over the recently years of rare plants and to seek measures for their survival. These methods were used while writing the work: for the identifying superfluity of rare plants the monitoring methods were applied prepared by the Botanical Institute (prepared by Zigmantas Gudžinskas 2001, Botanical Institute, in Flora and Geobotany laboratory). By using descriptive method it was evaluated the superfluity and coating of every sort of plant for populations association using Braun- Blanquet rates scale. After research and evaluating spread of rare plants instituted that 7 of 11 rare plants are growing in the zone of antropogenic effect. They growing places are near the stream, mound and educational path. Rare plants in the botanical conservation area of Vidzgiris are influencing by intensive recreation, deforestation, rubbish. At the time of research estimated that number of Epipactis atrorubens has decreased. Number of Cypripedium calceolus has increase. Were found new places were rare plants can grow. That to secure protected rare plants growing places is need to fit farming mode like in the I group forest... [to full text]

We present a robust iterative sparseness-constrained interpolation algorithm using 2/3D curvelet frames and Fourier-like transforms that exploits continuity along reflectors in seismic data. By choosing generic transforms, we circumvent the necessity to make parametric assumptions (e.g. through linear/parabolic Radon or demigration) regarding the shape of events in seismic data. Simulation and real data examples for data with moderately sized gaps demonstrate that our algorithm provides interpolated traces that accurately reproduce the wavelet shape as well as the AVO behavior. Our method also shows good results for de-aliasing judged by the behavior of the (f-k)-spectrum before and after regularization.