A Survey of Languages for Specifying Dynamics: A Knowledge Engineering Perspective

A number of formal specification languages for knowledge-based systems has been developed. Characteristics for knowledge-based systems are a complex knowledge base and an inference engine which uses this knowledge to solve a given problem. Specification languages for knowledge-based systems have to cover both aspects. They have to provide the means to specify a complex and large amount of knowledge and they have to provide the means to specify the dynamic reasoning behavior of a knowledge-based system. We focus on the second aspect. For this purpose, we survey existing approaches for specifying dynamic behavior in related areas of research. In fact, we have taken approaches for the specification of information systems (Language for Conceptual Modeling and TROLL), approaches for the specification of database updates and logic programming (Transaction Logic and Dynamic Database Logic) and the generic specification framework of abstract state machine

Development of a Tomographic Atmospheric Monitoring System based on Differential Optical Absorption Spectroscopy

The aim of this thesis is to describe the design and development of a proof of concept for a commercially viable large area atmospheric analysis tool, for use in trace gas concentration mapping and quanti cation. Atmospheric monitoring is a very well researched eld, with dozens of available analytical systems and subsystems. However, current systems require a very important compromise between spatial and operational complexity. We address this issue asking how we could integrate the Di erential Optical Absorption Spectroscopy (DOAS) atmospheric analysis technique in a Unmanned Aerial Vehicle (UAV) with tomographic capabilities. Using a two-part methodology, I proposed two hypotheses for proving the possibility of a miniaturised tomographic system, both related to how the spectroscopic data is acquired. The rst hypothesis addresses the projection forming aspect of the acquisition, its matrix assembly and the resolution of the consequent equations. This hypothesis was con rmed theoretically by the development of a simulation platform for the reconstruction of a trace gas concentration mapping. The second hypothesis deals with the way in which data is collected in spectroscopic terms. I proposed that with currently available equipment, it should be possible to leverage a consequence of the Beer-Lambert law to produce molecular density elds for trace gases using passiveDOAS. This hypothesiswas partially con rmed, with de nite conclusions being possible only through the use of complex autonomous systems for improved accuracy. This work has been a very important rst step in the establishment of DOAS tomography as a commercially viable solution for atmospheric monitoring, although further studies are required for de nite results. Moreover, this thesis has conducted to the development of a DOAS software library for Python that is currently being used in a production environment. Finally, it is important to mention that two journal articles were published from pursuing this work, both in important journals with Impact Factors over 3.0.Era o objectivo deste trabalho descrever o processo de desenho e implementação de uma prova de conceito para um sistema de avaliação atmosférica comercialmente viável, para uso no mapeamento das concentrações de compostos traço na atmosfera. A avaliação atmosférica é um campo muito estudado, estando no presente momento disponíveis para instalação diversos sistemas e subsistemas com estas capacidades. No entanto, é marcante o compromisso que se veri ca entre a resolução espacial e a complexidade operacional destes equipamentos. Nesta tese, desa o este problema e levanto a questão sobre como se poderia desenvolver um sistema com os mesmos ns, mas sem este premente compromisso. Usando uma metodologia a duas partes, proponho duas hipóteses para comprovar a exequibilidade deste sistema. A primeira diz respeito à formação da matriz tomográ ca e à resolução das equações que dela derivam e que formam a imagem que se pretende. Con rmei esta hipótese teoricamente através do desenvolvimento de uma plataforma de simulação para a reconstrução tomográ ca de um campo de concentrações fantoma. A segunda é dirigida a aquisição de dados espectroscópicos. Proponho que com o material presentemente disponível comercialmente, deverá ser possível aproveitar uma consequência da lei de Beer-Lambert para retirar os valores de concentração molecular de gases traço na atmosfera. Foi apenas possível validar esta hipótese parcialmente, sendo que resultados mais conclusivos necessitariam de equipamentos automatizados dos quais não foi possível dispôr. No nal, este trabalho constitui um importante primeiro passo no estabelecimento da técnica de DOAS tomográ co como uma alternativa comercialmente viável para a análise atmosférica. Ademais, o desenvolvimento desta tese levou à escrita de uma biblioteca em Python para análise de dados DOAS actualmente usada em ambiente de produção. Por m, importa realçar que dos trabalhos realizados no decorrer da tese foram publicados dois artigos em revistas cientí cas com Impact Factor acima de 3

An evaluation of novel remotely sensed data to improve and verify ocean- atmosphere forecasting.

The aim of this study is to evaluate the use of novel remote observations and spatial data analysis to improve the skill of an ocean forecasting system for the central Mediterranean Sea. A high-resolution (0.042 by 0.042ๆ ocean forecasting system was setup consisting of an atmosphere model (NCEP Eta model) that was coupled to an ocean model (Princeton Ocean Model). This coupling consisted of the provision of surface atmospheric fluxes predicted at 3-hourly intervals to drive forward the ocean model. This research study dealt with a variety of aspects to improve this forecasting system using an inter-disciplinary approach. The main aspect of this thesis is an evaluation of novel, remotely- sensed data acquired by an orbiting passive microwave sensor as a tool to assess and improve ocean forecasting. Thus, SST derived by the Tropical Microwave Imager onboard the TRMM satellite was evaluated for its potential to define one of the lower boundary conditions of the Eta model. The impact was positive, and resulted in an average improvement of the skill of the model to predict lower surface marine winds by approximately 10%. TMI-data proved extremely useful to derive instantaneous turbulent heat fluxes and other surface geophysical fields that were needed to diagnose and fine-tune the skill of the Eta model to forecast these fields. The TMI SST product also proved to be a valuable data source for data assimilation by the ocean model. An optimised data assimilation scheme was derived resulting in a bias of just -0.05 С after a 15-day model integration run. This thesis shows how spatial data analysis can provide more detailed information about the high-resolution forecasts and their quality in addition to standard verification tools. Routines that explore the spatial data of the forecasts, observations and their relationship were developed and applied. Geostatistical analysis was used to model the spatial structure of the residual fields of the predictions and observations, and to translate the degree of spatial correlation in numerical and graphical terms

Air Traffic Management Abbreviation Compendium

As in all fields of work, an unmanageable number of abbreviations are used today in aviation for terms, definitions, commands, standards and technical descriptions. This applies in general to the areas of aeronautical communication, navigation and surveillance, cockpit and air traffic control working positions, passenger and cargo transport, and all other areas of flight planning, organization and guidance. In addition, many abbreviations are used more than once or have different meanings in different languages. In order to obtain an overview of the most common abbreviations used in air traffic management, organizations like EUROCONTROL, FAA, DWD and DLR have published lists of abbreviations in the past, which have also been enclosed in this document. In addition, abbreviations from some larger international projects related to aviation have been included to provide users with a directory as complete as possible. This means that the second edition of the Air Traffic Management Abbreviation Compendium includes now around 16,500 abbreviations and acronyms from the field of aviation

Processing Structured Hypermedia : A Matter of Style

With the introduction of the World Wide Web in the early nineties, hypermedia has become the uniform interface to the wide variety of information sources available over the Internet. The full potential of the Web, however, can only be realized by building on the strengths of its underlying research fields. This book describes the areas of hypertext, multimedia, electronic publishing and the World Wide Web and points out fundamental similarities and differences in approaches towards the processing of information. It gives an overview of the dominant models and tools developed in these fields and describes the key interrelationships and mutual incompatibilities. In addition to a formal specification of a selection of these models, the book discusses the impact of the models described on the software architectures that have been developed for processing hypermedia documents. Two example hypermedia architectures are described in more detail: the DejaVu object-oriented hypermedia framework, developed at the VU, and CWI's Berlage environment for time-based hypermedia document transformations

Data Assimilation for Atmospheric CO2: Towards Improved Estimates of CO2 Concentrations and Fluxes.

The lack of a process-level understanding of the carbon cycle is a major contributor to our uncertainty in understanding future changes in the carbon cycle and its interplay with the climate system. Recent initiatives to reduce this uncertainty, including increases in data density and the estimation of emissions and uptake (a.k.a. fluxes) at fine spatiotemporal scales, presents computational challenges that call for numerically-efficient schemes. Often based on data assimilation (DA) approaches, these schemes are common within the numerical weather prediction community. The goal of this research is to identify fundamental gaps in our knowledge regarding the precision and accuracy of DA for CO2 applications, and develop suitable methods to fill these gaps. First, a new tool for characterizing background error statistics based on predictions from carbon flux and atmospheric transport models is shown to yield improved estimates of CO2 concentration fields within an operational DA system at the European Centre for Medium-Range Weather Forecasts (ECMWF). Second, the impact of numerical approximations within existing DA approaches is explored using a simplified flux estimation problem. It is found that a complex interplay between the underlying numerical approximations and the observational characteristics regulates the performance of the DA methods. Third, a novel and versatile DA method called the geostatistical ensemble square root filter (GEnSRF) is developed to leverage the information content of atmospheric CO2 observations. The ability of GEnSRF to match the performance of a more traditional inverse modeling approach is confirmed using a series of synthetic data experiments over North America. Fourth, GEnSRF is used to assimilate high-density satellite observations from the recently launched GOSAT satellite, and deliver global data-driven estimates of fine-scale CO2 fluxes. Diagnostics tools are used to evaluate the benefit of satellite observations in constraining global surface fluxes, relative to a traditional surface monitoring network. Overall, this research has developed, applied, and evaluated a novel set of tools with unique capabilities that increase the credibility of DA methods for atmospheric CO2 applications. Such advancements are necessary if we are to accurately understand the critical controls over the atmospheric CO2 growth, and improve our understanding of carbon-climate feedbacks.PHDEnvironmental EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/96172/1/abhishch_1.pd