Stuttgart, Univ., Studienarbeit, 2006.

Vorgestellt wird ein neuer Dienst zum eigenverantwortlichen Software-Update von PC-Systemen, die unter Linux Red Hat 7.3 betrieben werden. Grundlage des Dienstes bildet das Verfahren YARU (Yum based Automatic RPM Update) als Bestandteil der im URZ eingesetzten Admin-Technologie für Linux-Rechner.

Konstanz, FH, Diplomarb., 2004.

This paper examines the impact of model update/renewal among three German car manufactures BMW, Audi, and Mercedes-Benz. The data set controls for the year effect from 1970 to 2017, and the model effect of the nine different models. Using a fixed effect penal data model, it is concluded that the update will lift the sales of the models in the two years following the year of update. Additionally, the sales of competitor models will decrease in the year of the update, and the following year. Finally, by studying the year effect, it is observed that the new market release usually arrives in the expansion phase of the bigger market.

Across boreal forests and resource rich areas, human-induced change is rapidly occurring at various spatial scales. In the past, satellite remote sensing has provided a cost effective, reliable method of monitoring these changes over time and over relatively small areas. Those instruments offering high spatial detail, such as Landsat Thematic Mapper or Enhanced Thematic Mapper (TM or ETM+), typically have small swath widths and long repeat times that result in compositing intervals that are too large to resolve accurate time scales for many of these changes. Obtaining multiple scenes and producing maps over very large, forested areas is further restricted by high processing costs and the small window of acquisition opportunity. Coarse spatial resolution instruments such as the Moderate Resolution Imaging Spectroradiometer (MODIS) or the Advanced Very High Resolution Radiometer (AVHRR) typically have short revisit times (days rather than weeks), large swath widths (hundreds of kilometres), and in some cases, hyperspectral resolutions, making them prime candidates for multiple-scale change detection research initiatives. <p>In this thesis, the effectiveness of 250m spatial resolution MODIS data for the purpose of updating existing large-area, 30m spatial resolution Landsat TM land cover map product is tested. A land cover polygon layer was derived by segmentation of Landsat TM data using eCognition 4.0. This polygon layer was used to create a polygon-based MODIS NDVI time series consisting of imagery acquired in 2000, 2001, 2002, 2003, 2004 and 2005. These MODIS images were then differenced to produce six multiple-scale layers of change. Accuracy assessment, based on available GIS data in a subregion of the larger map area, showed an overall accuracy as high as 59% with the largest error associated with change omission (0.51). The Cramers V correlation coefficient (0.38) was calculated using the GIS data. This was compared to the results of an index-based Landsat change detection, Cramers V=0.67. This thesis research showed that areas greater than 15 hectares are adequately represented (approximately 75% accuracy) with the MODIS-based change detection technique. The resulting change information offers potential to identify areas that have been burned or extensively logged, and provides general information on those areas that have experienced greater change and are likely suitable for analysis with higher spatial resolution data.

Across boreal forests and resource rich areas, human-induced change is rapidly occurring at various spatial scales. In the past, satellite remote sensing has provided a cost effective, reliable method of monitoring these changes over time and over relatively small areas. Those instruments offering high spatial detail, such as Landsat Thematic Mapper or Enhanced Thematic Mapper (TM or ETM+), typically have small swath widths and long repeat times that result in compositing intervals that are too large to resolve accurate time scales for many of these changes. Obtaining multiple scenes and producing maps over very large, forested areas is further restricted by high processing costs and the small window of acquisition opportunity. Coarse spatial resolution instruments such as the Moderate Resolution Imaging Spectroradiometer (MODIS) or the Advanced Very High Resolution Radiometer (AVHRR) typically have short revisit times (days rather than weeks), large swath widths (hundreds of kilometres), and in some cases, hyperspectral resolutions, making them prime candidates for multiple-scale change detection research initiatives. <p>In this thesis, the effectiveness of 250m spatial resolution MODIS data for the purpose of updating existing large-area, 30m spatial resolution Landsat TM land cover map product is tested. A land cover polygon layer was derived by segmentation of Landsat TM data using eCognition 4.0. This polygon layer was used to create a polygon-based MODIS NDVI time series consisting of imagery acquired in 2000, 2001, 2002, 2003, 2004 and 2005. These MODIS images were then differenced to produce six multiple-scale layers of change. Accuracy assessment, based on available GIS data in a subregion of the larger map area, showed an overall accuracy as high as 59% with the largest error associated with change omission (0.51). The Cramers V correlation coefficient (0.38) was calculated using the GIS data. This was compared to the results of an index-based Landsat change detection, Cramers V=0.67. This thesis research showed that areas greater than 15 hectares are adequately represented (approximately 75% accuracy) with the MODIS-based change detection technique. The resulting change information offers potential to identify areas that have been burned or extensively logged, and provides general information on those areas that have experienced greater change and are likely suitable for analysis with higher spatial resolution data.

A novel hybrid pulse-width modulation (PWM) update method is proposed to eliminate the effect of the one-step control time delay Td one without losing the full duty cycle range. Without the Td one to cause linear phase shifts that limit the control bandwidth and affect closed-loop stability, a very high quality digital current control can be achieved, such as a high closed current loop bandwidth, strong robustness against disturbances, ability to reach a very high fundamental frequency compared to switching frequency, etc. In a conventional digital control implementation, a sampling period (Tsamp) is allocated for the execution of samplings and computations, and the update of PWM outputs is delayed until the beginning of the following sampling period. This delayed PWM update method is the cause of the Td one. Instead of the delayed PWM update, if the PWM outputs are updated immediately after algorithm computations, then the effect of the Td one can be eliminated; however, the computation time delay Td comp from the current sampling instant through algorithm computations to the PWM update instant causes a reduced duty cycle range. Each of these two conventional PWM update methods has some shortcomings. A hybrid PWM update method is proposed to circumvent the aforementioned shortcomings and to incorporate only the advantages. The proposed method improves the performance by updating the PWM outputs multiple times during a Tsamp, whereas the PWM outputs are updated only one time during a Tsamp in the conventional methods. In spite of the simplicity of the proposed method, the performance improvements in stability, robustness and response characteristics are significant. On the other hand, the proposed method can be easily applied to many PWM based digital controls because of its simplicity. Additional to the hybrid PWM update method, a hybrid control method is proposed to optimize the sequence of control operations. It maximizes the current loops' robustness and minimizes the delay from the sampling of outer control loops' variables, such as voltage and speed, to the duty cycle update instant. The minimum delay enables the maximization of the outer control loops' bandwidth. Additionally, a corrective neutral offset voltage injection method is proposed to correct small PWM output deviations that may occur with the hybrid PWM update method. Utilizing a three-phase voltage source inverter with a permanent magnet synchronous machine as the platform, a deadbeat current control and a high speed ac drive experiments have been conducted to demonstrate the feasibility and validity. Notable results include a closed current loop response of one Tsamp with the deadbeat control and a 500 Hz current fundamental frequency with 1 kHz switching frequency in the high speed ac drive. / Ph. D. / A novel hybrid pulse-width modulation (PWM) update method is proposed to improve the performance of power electronics applications. PWM is a modulation technique that is typically used in power electronics to encode a control signal. A delayed PWM update method and an immediate PWM update method are two conventional PWM update methods, and each of these conventional methods has shortcomings. The delayed PWM update method, as the name implies, delays the update of PWM outputs until the beginning of next cycle. This delayed update ensures that PWM signals have the full range; however, it causes an update delay in control loops, which degrades the control loops’ response speed. On the other hand, the immediate PWM update method, as the name implies, the update of PWM outputs is executed as soon as the control signals are available to be updated. This immediate update eliminates the update delay, but it loses the full range of PWM signals. The hybrid PWM update method is proposed to combine the delayed and immediate PWM update methods, in which the combination can eliminate the update delay without the loss of the full signal range. The proposed method is quite simple; however, the performance improvements in stability, robustness, and response characteristics are significant. On the other hand, the proposed method can be easily applied to many PWM based digital controls because of its simplicity. The proposed method is implemented on a three-phase voltage source inverter with a permanent magnet synchronous machine, and the feasibility and validity are demonstrated with a deadbeat current control algorithm and a high speed ac drive experiment. In the experiments, a very high quality digital current control is achieved, such as a high closed current loop bandwidth, strong robustness against disturbances, ability to reach a very high fundamental frequency compared to switching frequency, etc.

Multicore processors have become prevalent and spurred interest in scalable synchronization mechanisms, such as Read-Copy Update. While RCU is popular in monolithic operating system kernels it has yet to see an implementation in a microkernel environment. In this thesis we design and implement RCU for the microkernel operating system HelenOS. Moreover, we explore potential uses of RCU in HelenOS and illustrate its utility in both the kernel and user space. Benchmarks demonstrate that the RCU implementation provides linearly scalable read-sides and incurs significantly less overhead than traditional locking even if uncontended. Furthermore, RCU was used in user space to speed up traditional locking 2.6 times in the common case. In the kernel, RCU ensured linear scalability of a previously non-scalable futex subsystem. Powered by TCPDF (www.tcpdf.org)

Der Vortrag gibt einen Überblick zu RPM als Paketverwaltung für Unix/Linux-Systeme. Der Bau von RPM-Paketen wird an einem einfachen Beispiel skizziert. Paketverwaltungswerkzeuge (yum) werden vorgestellt.

In this master paper are analyzed services which are offered in GSM network. There is review of offered possibilities and its resources. There have been created model which imitates mass following service in mobile network. There have been made research by this created tool which quantitatively evaluates general quantity of update and paging procedures depending on size of location area and type of subscriber. There have been noticed some tendencies which depend on: paging period, size of location area and the ratio of transfered mesages by location updating and by paging procedures.