Using formal methods to support testing

Formal methods and testing are two important approaches that assist in the development of high quality software. While traditionally these approaches have been seen as rivals, in recent years a new consensus has developed in which they are seen as complementary. This article reviews the state of the art regarding ways in which the presence of a formal specification can be used to assist testing

Synthesis of Organo-metallic Coordination Polymers for Thermoelectric Application

As an intriguing class of thermoelectric (TE) candidates, organometallic coordination polymers (OMCPs) have become a new research focus in this area, regardless of the extensive research on inorganic and organic thermoelectric materials. This thesis showcases the synthesis and comprehensive characterization of a series of linear OMCPs based on metal-bis(dithiolato) coordination, Ni-ett, Ni-diett and Ni-btt (Chapter 2). The studies proved that changing organic ligands is a successful strategy to tune the thermoelectric properties of OMCPs, including electrical conductivity, Seebeck coefficient and power factor. By developing complex model for analogous spectroscopic study, we proved the polymer frames of three OMCPs are radial involving. Moreover, alternative synthetic route was also developed for polymer Ni-btt. Meanwhile, a couple of structural isomeric ligands OMCPs (Chapter 3), benzene-1,2,3,4-tetrakis(thiolate) and benzene-1,2,4,5-tetrakis(thiolate), were employed to synthesize mono-ligand OMCPs (Ni-ibtt and Ni-btt) and dual-ligand OMCPs Ni(ibtt)x(btt)1-x. The comparative study upon their thermoelectric properties was correlated with their structural difference in both intrachain and interchain characters. Regardless of organic bridging ligand, the metal center is the other most important role on the thermoelectric properties of OMCPs. Systematic comparison among OMCPs with different metal centers cross reports is usually unfeasible, as chemical composition and properties for a certain OMCP formula usually (like Ni-ett) differ from ii report to report and involve multiple reaction and measurement factors. In this study, OMCPs with various metal cations were synthesized in the M-ett and M-btt system to conduct a parallel comparison in their thermoelectric performance (Chapter 4). Preliminary molecular design and synthesis work were also carried out to experimentally obtain the OMCPs based on benzenetetrathiolate backbone with different sidechains, to examine the effect of sidechains on thermoelectric properties in this system

Soporte herramental para el Test Template Framework

Este proyecto trata sobre la automatización y extensión del Test Template Framework (TTF). El TTF es un método de testing basado en modelos (MBT) especialmente orientado a testing de unidad a partir de especificaciones Z. Aunque el TTF es un método sólido y fue ampliamente estudiado desde su primera publicación, la comunidad de MBT fue perdiendo interés en él. Nosotros creemos que esto se debió, al menos en parte, a la falta o dificultad aparente en dotarlo de un apoyo herramental. De hecho, algunos han sugerido que la generación de casos de prueba abstractos siguiendo el TTF es una actividad manual que requiere que los usuarios manipulen predicados complejos. La intención de este proyecto es mostrar que estas conclusiones son al menos dudosas, implementando una herramienta, llamada Fastest. Fastest no solo es capaz de producir automáticamente casos de prueba abstractos sino que además podrá cubrir las necesidades de la comunidad Z en relación a herramientas de MBT.Eje: Ingeniería de SoftwareRed de Universidades con Carreras en Informática (RedUNCI

Non-Linear Chirp Spread Spectrum Communication Systems of Binary Orthogonal Keying Mode

Chirp spread spectrum (CSS) is a suitable choice of modulation signals for wireless communications, due to its inherited advantages such as low transmission power, simplicity of implementation, good interference rejection capability. Linear chirps are common choices in practical CSS systems of binary orthogonal keying (BOK) mode. However, linear chirps generally require the time-bandwidth product of each chirp signal to be 60 sHz or more in order to achieve desirable orthogonality requirements. Thus, a BOK CSS system based on linear chirps has to occupy very wide bandwidth, which is a very precious resource for wireless communication. Clearly, the requirement on broad frequency bandwidth is a major limiting factor for the widespread adoption of the BOK linear CSS system in practice. To overcome this drawback, it is worthwhile to explore other types of chirp signals outside the linear domain, which can potentially reduce the bandwidth requirement without jeopardizing the system performance. This is the main objective of the current research. In this dissertation, a pair of non-linear chirps has been discovered, which has the potential to replace linear chirps for BOK CSS systems. After exploring desirable properties of non-linear chirps, it is demonstrated that a significant performance advantage on orthogonality over linear chirps can be achieved by a pair of sine or cosine chirps. Subsequently, properties of sine and cosine chirps are analyzed mathematically. Derivations of spectral characteristics, autocorrelation and cross-correlation for both sine and cosine chirps are carried out respectively. Finally, comparison of sine chirps of four different time periods (i.e. half time period, full time period, triple time period, and quadruple time period) are made in terms of their cross-correlation and autocorrelation properties. It has been concluded that full period sine (FPS) chirps are the better choice for this particular application among the sine chirps. Performance of a BOK CSS system based on FPS chirps has been evaluated in three typical scenarios. Firstly, BER (bit error rate) performance of the BOK FPS CSS system in an additive white Gaussian noise (AWGN) channel is derivated. Furthermore, performance comparison in terms of BERs between linear chirps and FPS chirps is examined. Secondly, effects of Doppler shift on the BOK FPS CSS system are analyzed. The effect of Doppler shift between linear chirps and FPS chirps has been compared. Thirdly, BER performance of the BOK FPS CSS system in a fading environment (Rayleigh channel) has been analyzed. Moreover, BER performance comparisons between linear chirps and FPS chirps in the AWGN+Rayleigh channel with and without a Doppler shift have also been studied. Using analytic means and numerical simulations, this dissertation has conclusively demonstrated that a pair of orthogonal FPS chirps has the capability of replacing linear chirp in BOK CSS systems

Novel Covalent Organic Frameworks (COFs) for Electrochemical Energy Storage and Conversion

Covalent Organic Frameworks (COFs) are a new type of crystalline porous organic materials composed of covalently linked organic molecular modules. They possess the advantages of ordered channels, nano-scale pore structures, large specific surface areas and high crystallinity. Meanwhile, unlike traditional linear polymerization leading to uncontrolled product structures, COFs can be designed to form highly regular structures in two or even three dimensions. In addition, rigid structures can provide excellent stability for COFs. Furthermore, the designable structure allows functional groups to be introduced into COFs to meet the specific requirements of devices. As a result, COFs have been widely used in various fields. In particular, COFs have been found to be suitable for electrochemical energy conversion and storage applications. In this thesis, I present two conceptual applications of COFs as electrochemical active material in supercapacitors for energy storage and as electrocatalysts bearing the metal-nitrogen-carbon single-atom structure for the oxygen reduction reaction. The results demonstrated in this thesis represent the specific applications of COFs in electrochemistry, offering further possibilities and new ideas for developing novel materials for electrochemical energy storage and conversion

Integrated End-to-End NEO Threat Mitigation Software Suite

Protecting Earth from the threat implied by the Near Earth Objects (NEO) is gaining momentum in recent years. In the last decade a number of mitigation methods have been pushed forward as a possible remedy to that threat, including nuclear blasts, kinetic impactor, gravity tractors and others. Tools are required to evaluate the NEO deflection performances of each of the different methods, coupled with the orbital mechanics associated to the need to transfer to the target orbit and maybe rendezvous with it. The present suite of tools do provide an integral answer to the need of determining if an asteroid is to collide with Earth (NIRAT tool), compute the required object deflection (NEODET tool) and assess the design features of the possible mitigation space missions (RIMISET tool). The tools are presented, their design analyzed as well as the methods and architecture implemented. Results are provided for two asteroids 2011 AG5 (using the orbit determination solution where this asteroid still was a risk object) and 2007 VK184 and the obtained data discussed in comparison to other results

Acoustic tests of duct-burning turbofan jet noise simulation: Comprehensive data report. Volume 2: Model design and aerodynamic test results

The selection procedure is described which was used to arrive at the configurations tested, and the performance characteristics of the test nozzles are given

Crew appliance study

Viable crew appliance concepts were identified by means of a thorough literature search. Studies were made of the food management, personal hygiene, housekeeping, and off-duty habitability functions to determine which concepts best satisfy the Space Shuttle Orbiter and Modular Space Station mission requirements. Models of selected appliance concepts not currently included in the generalized environmental-thermal control and life support systems computer program were developed and validated. Development plans of selected concepts were generated for future reference. A shuttle freezer conceptual design was developed and a test support activity was provided for regenerative environmental control life support subsystems