Dissertations / Theses on the topic 'Post-processor'

Vibrations caused due to aerodynamic excitation may cause severe limitation to the performance of turbomachines. The force resulting from the non-uniform pressure distribution within the labyrinth cavity is identified as a major source of this excitation. In order to perform rotor dynamic evaluation of rotor-bearing-seal system, accurate prediction of this force is essential.

A visual basic based front-end, for a labyrinth seal analysis program, has been designed herein. In order to accurately predict the excitation force, proper modeling of labyrinth leak path is important. Thus, the front-end developed herein incorporates a leak-path geometric diagram for visual analysis of labyrinth leak path and tooth location. Furthermore, to investigate influence of various operating conditions and gas properties on excitation force (effective cross-coupling stiffness), a parametric study is performed on both the eye seal and the balance piston labyrinth seal.
Master of Science

This thesis presents the design concepts and development of an interface (Pre- Pro2004) utilizing geodatabases for the Hydrologic Modeling System (HMS) of the Hydrologic Engineering Center (HEC). HMS is a rainfall-runoff model which supports lumped-parameter as well as distributed-parameter based modeling. PrePro2004 uses the spatial-analysis as well as data handling capabilities of ArcGIS. The spatial data are processed to create input files for HMS. These input files and the output from HMS are stored in two geodatabases which were developed using data model concepts. The tools are provided to reproduce an HMS model from the data inside these geodatabases. The interface is developed based on the DataCentric approach which brings different hydrologic and hydraulic models together. This approach aims to attain a long-term goal of utilizing the same data for different hydrologic or hydraulic models with additional model specific requirements. Two case studies are presented to show the applications of the tools developed. The first case study details the creation of HMS input files for Salado Creek watershed with Digital Elevation Model as input. It includes the importation of an existing HMS model for Salado Creek watershed as Appendix C. The second case study details the creation of HMS input files for the Bull Creek watershed, with land use and soil type data as inputs. It describes the capabilities of tools developed in detail.

Rotor dynamic analysis, which requires extensive amount of data and rigorous analytical processing, has been eased by the advent of powerful and affordable digital computers. By incorporating the processor and a graphical interface post processor in a single set up, this program offers a consistent and efficient approach to rotor dynamic analysis. The graphic user interface presented in this program effectively addresses the inherent complexities of rotor dynamic analyses by linking the required computational algorithms together to constitute a comprehensive program by which input data and the results are exchanged, analyzed and graphically plotted with minimal effort by the user. Just by selecting an input file and appropriate options as required, the user can carry out a comprehensive rotor dynamic analysis (synchronous response, stability analysis, critical speed analysis with undamped map) of a particular design and view the results with several options to save the plots for further verification. This approach helps the user to modify the design of turbomachinery quickly, until an efficient design is reached, with minimal compromise in all aspects.

Most existing telephone networks transmit narrowband coded speech which has been bandlimited to 4 kHz. Compared with normal speech, this speech has a muffled quality and reduced intelligibility, which is particularly noticeable in sounds such as /s/, /f/ and /sh/. Speech which has been bandlimited to 8 kHz is often coded for this reason, but this requires an increase in the bit rate. Wideband enhancement is a scheme that adds a synthesized highband signal to narrowband speech to produce a higher quality wideband speech signal. The synthesized highband signal is based entirely on information contained in the narrowband speech, and is thus achieved at zero increase in the bit rate from a coding perspective. Wideband enhancement can function as a post-processor to any narrowband telephone receiver, or alternatively it can be combined with any narrowband speech coder to produce a very low bit rate wideband speech coder. Applications include higher quality mobile, teleconferencing, and internet telephony. This thesis examines in detail each component of the wideband enhancement scheme: highband excitation synthesis, highband envelope estimation, and narrowband-highband envelope continuity. Objective and subjective test measures are formulated to assess existing and new methods for all components, and the likely limitations to the performance of wideband enhancement are also investigated. A new method for highband excitation synthesis is proposed that uses a combination of sinusoidal transform coding-based excitation and random excitation. Several new techniques for highband spectral envelope estimation are also developed. The performance of these techniques is shown to be approaching the limit likely to be achieved. Subjective tests demonstrate that wideband speech synthesized using these techniques has higher quality than the input narrowband speech. Finally, a new paradigm for very low bit rate wideband speech coding is presented in which the quality of the wideband enhancement scheme is improved further by allocating a very small bitstream for highband envelope and gain coding. Thus, this thesis demonstrates that wideband speech can be communicated at or near the bit rate of a narrowband speech coder.

This diploma thesis deals with design and implementation of complex software system for post-production of popular music. The system was implemented as a plug-in module in C++ language using JUCE application framework. The emphasis was on creating a well arranged and intuitive graphic user interface. The plug-in provides a set of audio effects and processors that can be connected into the desired graph structure. For less experienced users, there is a database of preset configurations usable for a variety of input signals.

碩士
國立交通大學
電子研究所
84
In the thesis, post-processing of 3D Graphic Rendering Processor (3DGP) is studied. A proposed architecture for 3DGP is implemented, which includes the operations related to stencil, Z and RGBA buffers. The charcateristics of various RAM (Random Access Memory) chips are analyzed, then BEDO DRAM and VRAM are choosen for frame buffer storage. Finally, the designs written in Verilog HDL are synthesized by Synopsys using PHILIPS' cell library which is based on 3.3V, 0.5um, triple-metal semiconductor technology.The results of simulation show that the peak performance of local buffer is 20M pixels/sec, and RGBA buffer is 5M pixels/sec.

VecTor is a suite of computer programs developed for the nonlinear finite element analysis of reinforced concrete structures. Due to the substantial nature of output data produced by the programs, accessing pertinent analysis information is not easily accomplished. A graphics-based post-processor would greatly improve the overall utility of the VecTor programs by allowing the multitude of information to be visually displayed and manipulated for the purposes of data synthesis and rapid verification of results. The intent of this manual is to demonstrate a post-processor program which reads and displays the results of VecTor-based analyses in a robust and straightforward manner. The proposed post-processor program, named Janus, will provide the user with the capability to display both local and global response characteristics. Janus will allow the user to comprehensively recall and manipulate structural analysis results on a model-wide basis as well as display pertinent information for individually specified elements of interest.

碩士
國立成功大學
航空太空工程學系碩博士班
95
Development of post-processor for diesel engines can reduce air pollution in significance. How to monitor the post-processor device to keep it function efficiently, the data acquisition using proper sensors and wireless data transmission to monitor station would be major tools to study. This research presents a measurement system for mobile devices and record data for monitoring station. The measurement system is focus on establishing a sensor data acquisition system for exhausted gas in the post-processor; while the monitoring system is focus on data transmission by wireless communication. The monitoring system integrates microprocessor and the computer to accomplish a mobile and location free data transmission. The importance of this thesis determines suitable wireless communication tool to effectively overcome the serious problems resulting from abominable environment. Through the tests and practically instrument setup, the proposed wireless data transmission has overcome wireless device selection, antenna setting, noise elimination and data rate adjustment to accomplish an unmanned monitoring system in high stability and reliability.

碩士
國立中興大學
電機工程學系所
102
This thesis presents circuit design of the post-processor used in low density parity check (LDPC) decoders to reduce error floors in wireless communication systems. The error floor often occurs in LDPC decoders. It can be divided into quantization errors and absorbing errors. We have proposed the reset layer min sum algorithm (R-LMSA) previously to improve the error floor phenomenon due to the quantization error of the LDPC decoder without hardware overhead. It can make the error floor lower than 10-6, which meets the specifications of the popular wireless communication systems. However, it can not satisfy the system requiring BER less than 10-7. In this thesis, in addition to improve the R-LMSA, we investigate and analyze the error floor caused by absorbing errors, then improve the previously proposed check node tracing with boundary search (CNTBS) algorithm. Through simulation, one extra reset was inserted into the pre-determined eight iterations, and the variable boundary and check node tracing with boundary invert (CNTBI) is proposed to make the error floor do not appear when the BER close to 10-9. Finally, the proposed post-processor algorithm was implemented using field programmable gate array (FPGA) based on the look up table (LUT) method to minimize the circuit complexity. The occupied FPGA resource is approximately 1/2 of the LDPC decoder required.

碩士
大葉大學
機械與自動化工程學系
98
In this study, this research will use the Fuji Electrical and open programmable logic controller (OPLC), its controller ST (Structured Text) programming language keep up with the creative process into a discharge command buffer control (English) under the integration framework , with commercially available CAM software package to create a simple type into a high-precision electrical discharge machining system innovation (English), looking forward to this simple control structure, after the traditional CNC machines are slightly modified, will be able to enhance the precision and CNC machines processing functions, in order to discharge in the processing mold cavity formed out of you want to take with computer-aided design (CAD) and computer aided manufacturing software (CAM), use this code with the finished product can be processed the same electrode, then This electrode discharge machining of metal materials can be formed after a cavity, in order to achieve the purpose of processing, this study will be established within OPLC deep discharge control system required that the establishment of real-time control of the gap controller, electrode wear compensation device, Trajectory Interpolator, axis position controller, discharge parameter transmission, I / O configuration and post processors. In order to estimate the consumption of electrode is used in this study even wear compensation method, design and produce innovative as a result of electrical discharge machining shop and consume and timely compensation control method can be omitted electrode consumption demand formula. And processing for experimental analysis. Z-axis to obtain compensation, while a personal computer (PC) using VB (Visual Basic), and CAD / CAM software, human-machine interface and were established to handle complex curve processing, the integration into the use of personnel can use this to screen for discharge processing operations, but also between the PC and OPLC data communication interface. Finally this control system installed in the EDM machine table, and the actual processing and functional tests to understand the control system produced by this study, the actual EDM machines in processing the case.

碩士
大葉大學
機械與自動化工程學系
97
The purpose of this study is to establish a standard post-processor for a specified multi-spindle machine tool, and build a virtual machine for machining simulation. This post-processor can generate standard NC codes by CL path information. A multi-spindle machine tool NC-2432/LV was used to verify this post-processor embedded in a specified CAM system. Computer-aided simulation machining can help users to identify possible NC code error in machining process, spindle interference and collision, and whether machined part meets design requirement or not? Post-processor can convert tool paths generated by a CAM system into NC codes that CNC machine tool can accept. It is a important interface between design and manufacturing; as a of multi-spindle machine tool is operated much more complicated than ordinary standard single-spindle one, its post-processor design is more complex, too. This study aimed to create a post-processor and generate NC code for a specified multi-spindle machine tool, and establish machining model the same as actual machine by virtual machining software for simulation validation. The results proved that the post-processor established in this study can be applied in actual machining.

博士
國立清華大學
動力機械工程學系
99
This thesis deals with not only the tool path planning and cutting deviation analysis for sculptured surface machining but also kinematic transformation algorithms for different types of 5-axis machine centers. A generalized expression is presented first to define the cutting contact location for any type of milling tools. The actual cutting contact point and the cutter location can be determined by tool orientation angles. Furthermore, the gouge avoidance criterion is utilized with the admissible tool orientation classification and a localization algorithm is derived to calculate error estimation along tool paths. The inverse kinematics between two independent chains about the tool and workpiece is solved and the tool compensation procedure is established for each 5-axis machine configuration. Computer implementation and illustrative examples are also executed for qualitative and quantitative analysis. The theoretical and practical issues associated with this thesis could help to generate 5-axis CNC tool paths automatically from CAD model and to promote general post-processor developement for futher applications.

碩士
國立臺灣大學
電子工程學研究所
100
In DNA Sequence Assembly, assembly tools align and merge high-throughput DNA sequences to reconstruct original DNA sequence. In the general assembly flow, the pre-processor first filters out low quality reads to decrease the error rate as well as the problem size. Secondly, bases are changed from the 2-base color coding to pseudo bases that are compatible with general assembly tools. The second step is sequence assembly. After assembly, the post-processor changes pseudo-base results back to genome sequences. Since each of the three steps takes about 1/3 of the total computation time, we decide first to improve the performance of the pre-filter and post-processor. In this study, we proposed a pre-filter and post-processor hardware design for the assembly tool, Velvet. In the pre-filter, due to hardware advantages of parallel processing and pipelining, reads can be filtered efficiently. The execution time is linearly proportional to the number of reads but independent of the read length. In addition, it is a scalable architecture to speed up further by increasing the number of parallel computational units. As for the post-processor, we propose a new approach to change pseudo bases back to real bases by using only first several short reads in the whole sequence and the Velvet results which is also implemented in a pipeline manner. The chips are implemented with TSMC 90 nm technology. It is capable of processing 256 M reads and the maximum read length is 63. The two chip sizes are 2367051 um2 and 774724 um2, and the chips operate at 100 MHz. When compared to software approaches, the speed-up of the pre-filter and post-processor are as high as 11000 times and 34000 times, respectively.

A suite of NLFEA programs, VecTor, has been developed at the University of Toronto. However, this software still requires the development of other functions to execute some types of analyses. One of the required functions is the consideration of transient creep strain in the heat transfer analysis. Moreover, there is a strong need to develop a general graphics-based post-processor applicable to VecTor programs. The first objective of this thesis is to develop a function considering the effect of the transient creep strain, because it can have significant influence on the behaviour of concrete under elevated temperatures. The second purpose of this thesis is to construct the new analysis visualization features compatible with entire suite of VecTor programs. As the result, the modified post-processor, JANUS, has had its abilities expanded significantly.

[ES] La cuantificación de la incertidumbre predictiva es de vital importancia para producir predicciones hidrológicas confiables que soporten y apoyen la toma de decisiones en el marco de la gestión de los recursos hídricos. Los post-procesadores hidrológicos son herramientas adecuadas para estimar la incertidumbre predictiva de las predicciones hidrológicas (salidas del modelo hidrológico). El objetivo general de esta tesis es mejorar los métodos de post-procesamiento hidrológico para estimar la incertidumbre predictiva de caudales mensuales. Esta tesis pretende resolver dos problemas del post-procesamiento hidrológico: i) la heterocedasticidad y ii) la función de verosimilitud intratable. Los objetivos específicos de esta tesis son tres. Primero y relacionado con la heterocedasticidad, se propone y evalúa un nuevo método de post-procesamiento llamado GMM post-processor que consiste en la combinación del esquema de modelado de probabilidad Bayesiana conjunta y la mezcla de Gaussianas múltiples. Además, se comparó el desempeño del post-procesador propuesto con otros métodos tradicionales y bien aceptados en caudales mensuales a través de las doce cuencas hidrográficas del proyecto MOPEX. A partir de este objetivo (capitulo 2), encontramos que GMM post-processor es el mejor para estimar la incertidumbre predictiva de caudales mensuales, especialmente en cuencas de clima seco. Segundo, se propone un método para cuantificar la incertidumbre predictiva en el contexto de post-procesamiento hidrológico cuando sea difícil calcular la función de verosimilitud (función de verosimilitud intratable). Algunas veces en modelamiento hidrológico es difícil calcular la función de verosimilitud, por ejemplo, cuando se trabaja con modelos complejos o en escenarios de escasa información como en cuencas no aforadas. Por lo tanto, se propone el ABC post-processor que intercambia la estimación de la función de verosimilitud por el uso de resúmenes estadísticos y datos simulados. De este objetivo específico (capitulo 3), se demuestra que la distribución predictiva estimada por un método exacto (MCMC post-processor) o por un método aproximado (ABC post-processor) es similar. Este resultado es importante porque trabajar con escasa información es una característica común en los estudios hidrológicos. Finalmente, se aplica el ABC post-processor para estimar la incertidumbre de los estadísticos de los caudales obtenidos desde las proyecciones de cambio climático, como un caso particular de un problema de función de verosimilitud intratable. De este objetivo específico (capitulo 4), encontramos que el ABC post-processor ofrece proyecciones de cambio climático más confiables que los 14 modelos climáticos (sin post-procesamiento). De igual forma, ABC post-processor produce bandas de incertidumbre más realista para los estadísticos de los caudales que el método clásico de múltiples conjuntos (ensamble).
[CAT] La quantificació de la incertesa predictiva és de vital importància per a produir prediccions hidrològiques confiables que suporten i recolzen la presa de decisions en el marc de la gestió dels recursos hídrics. Els post-processadors hidrològics són eines adequades per a estimar la incertesa predictiva de les prediccions hidrològiques (eixides del model hidrològic). L'objectiu general d'aquesta tesi és millorar els mètodes de post-processament hidrològic per a estimar la incertesa predictiva de cabals mensuals. Els objectius específics d'aquesta tesi són tres. Primer, es proposa i avalua un nou mètode de post-processament anomenat GMM post-processor que consisteix en la combinació de l'esquema de modelatge de probabilitat Bayesiana conjunta i la barreja de Gaussianes múltiples. A més, es compara l'acompliment del post-processador proposat amb altres mètodes tradicionals i ben acceptats en cabals mensuals a través de les dotze conques hidrogràfiques del projecte MOPEX. A partir d'aquest objectiu (capítol 2), trobem que GMM post-processor és el millor per a estimar la incertesa predictiva de cabals mensuals, especialment en conques de clima sec. En segon lloc, es proposa un mètode per a quantificar la incertesa predictiva en el context de post-processament hidrològic quan siga difícil calcular la funció de versemblança (funció de versemblança intractable). Algunes vegades en modelació hidrològica és difícil calcular la funció de versemblança, per exemple, quan es treballa amb models complexos o amb escenaris d'escassa informació com a conques no aforades. Per tant, es proposa l'ABC post-processor que intercanvia l'estimació de la funció de versemblança per l'ús de resums estadístics i dades simulades. D'aquest objectiu específic (capítol 3), es demostra que la distribució predictiva estimada per un mètode exacte (MCMC post-processor) o per un mètode aproximat (ABC post-processor) és similar. Aquest resultat és important perquè treballar amb escassa informació és una característica comuna als estudis hidrològics. Finalment, s'aplica l'ABC post-processor per a estimar la incertesa dels estadístics dels cabals obtinguts des de les projeccions de canvi climàtic. D'aquest objectiu específic (capítol 4), trobem que l'ABC post-processor ofereix projeccions de canvi climàtic més confiables que els 14 models climàtics (sense post-processament). D'igual forma, ABC post-processor produeix bandes d'incertesa més realistes per als estadístics dels cabals que el mètode clàssic d'assemble.
[EN] The predictive uncertainty quantification in monthly streamflows is crucial to make reliable hydrological predictions that help and support decision-making in water resources management. Hydrological post-processing methods are suitable tools to estimate the predictive uncertainty of deterministic streamflow predictions (hydrological model outputs). In general, this thesis focuses on improving hydrological post-processing methods for assessing the conditional predictive uncertainty of monthly streamflows. This thesis deal with two issues of the hydrological post-processing scheme i) the heteroscedasticity problem and ii) the intractable likelihood problem. Mainly, this thesis includes three specific aims. First and relate to the heteroscedasticity problem, we develop and evaluate a new post-processing approach, called GMM post-processor, which is based on the Bayesian joint probability modelling approach and the Gaussian mixture models. Besides, we compare the performance of the proposed post-processor with the well-known exiting post-processors for monthly streamflows across 12 MOPEX catchments. From this aim (chapter 2), we find that the GMM post-processor is the best suited for estimating the conditional predictive uncertainty of monthly streamflows, especially for dry catchments. Secondly, we introduce a method to quantify the conditional predictive uncertainty in hydrological post-processing contexts when it is cumbersome to calculate the likelihood (intractable likelihood). Sometimes, it can be challenging to estimate the likelihood itself in hydrological modelling, especially working with complex models or with ungauged catchments. Therefore, we propose the ABC post-processor that exchanges the requirement of calculating the likelihood function by the use of some sufficient summary statistics and synthetic datasets. With this aim in mind (chapter 3), we prove that the conditional predictive distribution is similarly produced by the exact predictive (MCMC post-processor) or the approximate predictive (ABC post-processor), qualitatively speaking. This finding is significant because dealing with scarce information is a common condition in hydrological studies. Finally, we apply the ABC post-processing method to estimate the uncertainty of streamflow statistics obtained from climate change projections, such as a particular case of intractable likelihood problem. From this specific objective (chapter 4), we find that the ABC post-processor approach: 1) offers more reliable projections than 14 climate models (without post-processing); 2) concerning the best climate models during the baseline period, produces more realistic uncertainty bands than the classical multi-model ensemble approach.
I would like to thank the Gobernación del Huila Scholarship Program No. 677 (Colombia) for providing the financial support for my PhD research.
Romero Cuellar, J. (2019). Improving hydrological post-processing for assessing the conditional predictive uncertainty of monthly streamflows [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/133999
TESIS