Rule-Based Software Verification and Correction

The increasing complexity of software systems has led to the development of sophisticated formal Methodologies for verifying and correcting data and programs. In general, establishing whether a program behaves correctly w.r.t. the original programmer s intention or checking the consistency and the correctness of a large set of data are not trivial tasks as witnessed by many case studies which occur in the literature. In this dissertation, we face two challenging problems of verification and correction. Specifically, verification and correction of declarative programs, and the verification and correction of Web sites (i.e. large collections of semistructured data). Firstly, we propose a general correction scheme for automatically correcting declarative, rule-based programs which exploits a combination of bottom-up as well as topdown inductive learning techniques. Our hybrid hodology is able to infer program corrections that are hard, or even impossible, to obtain with a simpler,automatic top-down or bottom-up learner. Moreover, the scheme will be also particularized to some well-known declarative programming paradigm: that is, the functional logic and the functional programming paradigm. Secondly, we formalize a framework for the automated verification of Web sites which can be used to specify integrity conditions for a given Web site, and then automatically check whether these conditions are fulfilled. We provide a rule-based, formal specification language which allows us to define syntactic as well as semantic properties of the Web site. Then, we formalize a verification technique which detects both incorrect/forbidden patterns as well as lack of information, that is, incomplete/missing Web pages. Useful information is gathered during the verification process which can be used to repair the Web site. So, after a verification phase, one can also infer semi-automatically some possible corrections in order to fix theWeb site. The methodology is based on a novel rewritBallis, D. (2005). Rule-Based Software Verification and Correction [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/194

Per un teatro di suoni. Riflessioni su possibili dimensioni sonore nelle creazioni site-specific di physical theatre

Taking physical theatre as a reference point, in this paper I aim to explore the possibilities for a theatre that starts from sounds and places to develop its own forms, structures and contents. In the first part I explain what the expression “physical theatre” can mean, then I focus on the issue of space in theatre, before devoting a section to some peculiarities of site-specific approaches to the performing arts. The next step is to take into consideration certain aspects of the sound dimension in theatre, before outlining considerations that can help to start an exploration of a theatre of sounds that promotes new spaces for a real dialogue of this art with society

The Relationship between Aspects of Reading Motivation and Learners’ EFL Reading Comprehension Ability: The Case of Second-Year EFL Students at Gambella University, Ethiopia

The purpose of this study was to investigate the relationship between aspects of reading motivation and reading comprehension ability of second-year EFL students at Gambella University, Ethiopia. The study was conducted in a sample of 40 EFL students selected through comprehensive sampling technique. To collect the required data for the study, questionnaire and reading comprehension test were used. The study was a quantitative cross-sectional research in its type, and it employed a correlation and multiple regression statistical procedures to analyze data. Pearson product moment correlation and multiple linear regression statistical procedure were followed. The statistical significance was tested at P= 0.5 level of significance. Accordingly, the value of the Adjusted R-square (R=.775) indicated strong fit. This implies that, among the eight aspects of reading motivation, six predictors computed in the model strongly predict EFL students reading comprehension ability.  Specifically, the aspects of reading motivation (grade, curiosity, involvement, work avoidance, self-efficacy and   importance) had strongly predicted learners reading comprehension ability. Thus, it was recommended that teachers should keep on motivating students and engage them on meaningful reading activities. Students have to realize the importance of aspects of reading motivation since they have significant relationship and strongly predict their EFL reading comprehension ability. Furthermore, further studies are crucial to address nonlinguistic constructs related with EFL learners reading comprehension ability since it was found that aspects of reading motivation predict 77.5% of EFL students reading comprehension ability in the present study. Keywords: reading , motivation,  comprehension, EFL students,ability DOI: 10.7176/JCSD/72-04 Publication date: January 31st 2024

Effect of Different Nitrogen Rate and Barley (Hordeum vulgare L.) Variety to different Growth Analysis at Hawassa, Southern Ethiopia

Nitrogen (N) is the most common limiting nutrient in agricultural systems throughout the world. Crops need sufficient available N to achieve optimum yields and adequate grain-protein content. Consequently, sub-optimal rates of N fertilizers typically cause lower economic benefits for farmers. On the other hand, excessive N fertilizer use may result in environmental problems such as nitrate contamination of groundwater and emission of N2O and NO. In spite of the economical environmental importance of good N fertilizer management, the development of an optimum fertilizer recommendation is still a major challenge in most agricultural systems. Nitrogen supplies have a strong influence on the physiological and phonological characteristics of crop as well as on the quality of barley growth, which have the capacity to enhanced yield and production of barley. In order to evaluate the physiological and quality assessment of barley in response to soil fertilization of nitrogen a field trail was carried out having randomized complete block design with four replications and three different treatments of nitrogen allotted to plots at planting and tillering growth stages. Results indicated that maximum leaf area ratio, maximum crop growth rate and maximum dry weight was recorded when the crop was none fertilized with as compared to fertilized nitrogen. Likewise maximum leaf area index was obtained with the non-fertilization of nitrogen. Control practice resulted in high values for all recorded parameters. Thus it is possible to obtain maximum physiological traits as well as vigorous barley through non nitrogen application. Keywords: Barley, leaf area index, leaf area ratio, crop growth rate, Biomass and nitrogen. DOI: 10.7176/ALST/86-01 Publication date:March 31st 2021

Determinants of Capital Structure of African Firms: A Categorical Analysis

This study contributes to capital structure literature by investigating the determinant factor of financing decision of firms operating in 13 African countries with different financial, institutional, legal and economic environments.  We employed categorical analysis so as to investigate the factors that influence the financing decision of firms operating in countries with underdeveloped and developed stock and banking sector. We also test in this study the pecking order and trade off theory is more statistically powerful in explaining firms’ financing decision of those African countries and the result confirms both pecking order and trade off theory. Our study found that asset tangibility, financial distress cost, profitability and Non debt tax shield are strong firm specific determinants of capital structure.  This study also found that corporate tax rate, banking sector development, GDP growth rate, and lending interest rate are the most important country specific determinants of capital structure. Rule of law is found to be strong determinants of capital structure of African firms. Keywords: Africa, Capitals structure, Country’s legal system, Country specific determinants, Pecking order theory, Trade off theor

Primary Teacher Education in Malawi: Insights Into Practice and Policy: Multi-Site Teacher Education Research Project (MUSTER), Country Report Three

Teaching/Communication/Extension/Profession,

Sandwich structures with cork agglomerate cores for thermal insulation purposes in aircraft

As the use of sandwich structures continues to increase rapidly for applications ranging from satellites, aircraft, ships, automobiles, rail cars, wind energy systems, and bridge construction (to mention only a few), lightweight and high strength structures have become indispensable to many high-tech industries such as aerospace, civil infrastructure and vehicle. Therefore, the demand for new materials has been rising which in turn led to the increasing use of composite sandwich structures applications. Utilizing natural materials over traditional synthetic structures allows avoiding the use of oil and other carbon products for the fabrication, which were otherwise needed, thus resulting in a reduction of carbon emissions. Besides being renewable, these materials provide such benefits as being both biodegradable and recyclable. In its simplest form a structural sandwich is composed of two thin stiff face sheets and a thick lightweight core bonded between them. The properties of primary interest for the core materials can be summarized as: low density, high shear modulus, high shear strength, elevated stiffness perpendicular to the faces and both good thermal and acoustic insulation characteristics. The commonly used core materials are foams, balsa wood and honeycombs, the latter consisting in superlight structures with high strength-to-weight and stiffness-to-weight ratios. Honeycombs can be defined as an array of open cells, formed from sheets of suitable material, bonded together at controlled intervals and then expanded to form hexagonal cells. However, recent developments resulted into new alternatives like cellular core structures such as the case of cork. Cork has an alveolar cellular structure similar to that of a honeycomb, and its cells are mostly formed by suberin, lignin and cellulose. Although it seems that natural cork has a poor mechanical behavior when compared with other types of core materials, such as synthetic foams, for some specific applications, cork can actually compete with these materials. Its low thermal conductivity combined with a reasonable compressive strength makes it an excellent material for thermal insulation purposes as well as for applications in which compressive loads are present. The work herein presented aims to study the feasibility of implementing cork, more specifically the NL20 cork agglomerate fabricated by Amorim Cork Composites, as the core material of sandwich structures with aluminum face sheets (Aalco 5754) by thermally characterizing nine circular sandwich panel samples through experimental tests. Taking into account the enormous challenges imposed by the global stake-holders of drastically reducing (75% per passenger/km) the environmental impact, such as the CO2 emissions associated to the current manufacturing, as well as the operational and maintenance technologies of the various ways of transport, it becomes paramount that aeronautical industry starts incorporating a high amount of recyclable components, in addition to being lighter. Therefore, one of the key objectives of this study is to lower the weight of the samples whilst maintaining their thermal characteristics by drilling different hole patterns into their cork cores. The core configurations differ in hole shape, diameter and depth so that their impact could be assessed. However, a uniform sample is included which served as the reference model for all others. The impact of the core´s mass regarding the component´s insulating ability was also investigated. All samples, which are thermally insulated on the sides in order to ensure one dimensional heat flow, were heated up to 80°C on the bottom face sheet and their individual insulating ability was determined by the measurement of the temperature at the center of the top face sheet with a contact thermocouple. The temperature distribution on the top face sheets was also recorded by a thermographic infrared camera positioned above the samples. The numerical analysis were carried out by resorting to the finite element code ABAQUS® v6.10-1. The experimental tests had to be performed first so that the experimental convective heat transfer coefficient could be determined and subsequently used in the numerical analysis. Heat transfer through radiation was proven to have very little influence on the results due to the small temperature differences between the samples and the surroundings, thus being practicably negligible. The conclusions drawn from the comparison between the experimental and the numerical results allow taking an important step towards the adoption of cork as the material of choice for the core of sandwich structures and should serve as basis or reference for future more detailed studies in this area.À medida que o recurso a estruturas sandwich continua a aumentar rapidamente para aplicações que vão desde satélites, aeronaves, navios, automóveis, veículos ferroviários a sistemas de energia eólica e construção de pontes (mencionando apenas alguns), estruturas leves e com resistência elevada tornaram-se indispensáveis para muitas indústrias de alta tecnologia tais como a aeroespacial, civil e de transporte em geral. Sendo assim, a procura de novos materiais tem vindo a aumentar o que por sua vez levou ao aumento da utilização de aplicações de estruturas sandwich de compósitos. A utilização de materiais naturais no lugar de estruturas sintéticas tradicionais permite evitar o uso de óleos e outros produtos de carbono para a fabricação, que caso contrário seriam necessários, resultando assim numa redução de emissões de carbono. Para além de serem renováveis, estes materiais fornecem benefícios por serem biodegradáveis e renováveis. Na sua forma mais simples uma sandwich estrutural é composto por duas faces finas e rígidas e um núcleo leve e espesso colocado entre as mesmas. As propriedades de interesse primário para os materiais do núcleo podem ser resumidas da seguinte forma: baixa densidade, módulo de corte elevado, resistência ao corte elevada, rigidez elevada na direção normal às faces e boas características isolantes tanto termicamente como acusticamente. Os materiais de núcleo frequentemente usados são espumas, balsa e estruturas em forma de favo de abelha, que consistem em estruturas superleves com elevadas razões de resistência-peso e rigidez-peso. A configuração favo de abelha pode ser definida como sendo uma matriz de células abertas, formadas a partir de folhas de materiais apropriados, ligadas entre si em intervalos controlados e depois expandidos em ordem a formar células hexagonais. No entanto, desenvolvimentos recentes resultaram em novas alternativas, tais como estruturas de núcleo celular que é o caso da cortiça. A cortiça tem uma estrutura celular alveolar similar ao da configuração de favo de abelha e as suas células são principalmente compostas por suberina, lenhina e celulose. Embora pareça que cortiça natural tenha um fraco comportamento mecânico quando comparado a outros tipos de materiais de núcleo, tais como espumas sintéticas, para algumas aplicações específicas, a cortiça consegue mesmo competir com estes materiais. A sua baixa condutividade térmica combinada com a sua resistência à compressão razoável torna a cortiça um excelente material para propósitos de isolamento térmico como também para aplicações em que estão presentes cargas de compressão. O trabalho aqui apresentado visa estudar a viabilidade de implementar cortiça, mais especificamente o aglomerado de cortiça NL20 fabricado por Amorim Cork Composites, como o material de núcleo de estruturas sandwich com faces de alumínio (Aalco 5754) caracterizando termicamente nove provetes de painéis sandwich circulares através de ensaios experimentais. Tendo em conta os desafios enormes impostos pelos stake-holders globais de reduzir drasticamente (75% por passageiro/km) o impacto ambiental, tais como as emissões de CO2, associadas às tecnologias de fabricação, bem como de operação e manutenção atuais dos vários tipos de transporte, torna-se fundamental que a indústria aeronáutica começa por incorporar uma quantidade elevada de componentes recicláveis, para além de mais leves. Sendo assim, um dos objetivos chave deste estudo é reduzir o peso dos provetes mantendo as suas características térmicas ao aplicar diferentes padrões de furo nos seus núcleos de cortiça. Os configurações de núcleo diferem em forma do furo, diâmetro e profundidade de forma a que a influência destes fatores pudesse ser estudada. No entanto, é incluído um provete uniforme que irá servir de modelo de referência para os restantes. O efeito que a massa de cortiça tem na capacidade isolante também foi estudada. Estes provetes, todos eles isolados termicamente lateralmente de forma a assegurar o fluxo de calor unidimensional, foram aquecidos a 80°C na face inferior e a sua capacidade isolante individual foi determinada através da medição da temperatura no centro da face superior com um termopar de contacto. A distribuição de temperatura nas faces superiores também foi registada através de uma câmara termográfica de infravermelhos posicionada acima dos provetes. As análises numéricas foram realizadas recorrendo ao código de elementos finitos ABAQUS® v6.10-1. Os ensaios experimentais tiveram que ser realizados em primeiro de forma a determinar o coeficiente convectivo experimental para posteriormente ser usado nas análises numéricas. A transferência de calor através de radiação foi provada como tendo muito pouca influência nos resultados devido às diferenças de temperatura reduzidas entre os provetes e a vizinhança, pelo que é praticamente desprezável. As conclusões tiradas a partir da comparação entre os resultados experimentais e numéricos permitem dar um passo importante no sentido da adoção de cortiça como o material de seleção para o núcleo de estruturas sandwich e deverão servir como base ou referência para estudos futuros mais detalhados nesta área