Understanding Variability-Aware Analysis in Low-Maturity Variant-Rich Systems

Context: Software systems often exist in many variants to support varying stakeholder requirements, such as specific market segments or hardware constraints. Systems with many variants (a.k.a. variant-rich systems) are highly complex due to the variability introduced to support customization. As such, assuring the quality of these systems is also challenging since traditional single-system analysis techniques do not scale when applied. To tackle this complexity, several variability-aware analysis techniques have been conceived in the last two decades to assure the quality of a branch of variant-rich systems called software product lines. Unfortunately, these techniques find little application in practice since many organizations do use product-line engineering techniques, but instead rely on low-maturity \clo~strategies to manage their software variants. For instance, to perform an analysis that checks that all possible variants that can be configured by customers (or vendors) in a car personalization system conform to specified performance requirements, an organization needs to explicitly model system variability. However, in low-maturity variant-rich systems, this and similar kinds of analyses are challenging to perform due to (i) immature architectures that do not systematically account for variability, (ii) redundancy that is not exploited to reduce analysis effort, and (iii) missing essential meta-information, such as relationships between features and their implementation in source code.Objective: The overarching goal of the PhD is to facilitate quality assurance in low-maturity variant-rich systems. Consequently, in the first part of the PhD (comprising this thesis) we focus on gaining a better understanding of quality assurance needs in such systems and of their properties.Method: Our objectives are met by means of (i) knowledge-seeking research through case studies of open-source systems as well as surveys and interviews with practitioners; and (ii) solution-seeking research through the implementation and systematic evaluation of a recommender system that supports recording the information necessary for quality assurance in low-maturity variant-rich systems. With the former, we investigate, among other things, industrial needs and practices for analyzing variant-rich systems; and with the latter, we seek to understand how to obtain information necessary to leverage variability-aware analyses.Results: Four main results emerge from this thesis: first, we present the state-of-practice in assuring the quality of variant-rich systems, second, we present our empirical understanding of features and their characteristics, including information sources for locating them; third, we present our understanding of how best developers\u27 proactive feature location activities can be supported during development; and lastly, we present our understanding of how features are used in the code of non-modular variant-rich systems, taking the case of feature scattering in the Linux kernel.Future work: In the second part of the PhD, we will focus on processes for adapting variability-aware analyses to low-maturity variant-rich systems.Keywords:\ua0Variant-rich Systems, Quality Assurance, Low Maturity Software Systems, Recommender Syste

An organizational model plan for the application of expanded educational broadcasting services in the formal secondary school education system of Zambia

Given the constraints of the present education system in Zambia; that is, lack of financial resources, shortage of skilled manpower and technical facilities, this study proposes that a system of expanded educational broadcasting services applied to these problems might bring about some alleviation of them. The study deals with the design of a framework for the development of expanded educational broadcasting services in the formal secondary education system of Zambia and is a selective exercise in the planning and utilization of educational broadcasting. It is designed in response to the need to plan and develop a systems of education that is more responsive to increasing numbers of students and to provide them with more opportunities for learning than the present systems. A draft of the plan was developed from a review of literature relevant to the Zambian situation from a local as well as other sources concerned with education in developing countries. Data were also gathered from secondary school teachers and educational administrators through the use of questionnaires. The plan was reviewed by a panel of six persons expert in the field of education in Zambia; the criteria for their selection were that they are in leadership positions. After they had read the plan, they were required to answer the questionnaire which accompanied the plan. The feedback obtained from the two questionnaires was used to revise the plan. Recommendations to the Government of Zambia based on the plan were considered from the point of view of appropriateness to the local situation, feasibility, implementation, desirability and efficiency. The final plan represented a comprehensive design which collected, analysed, and prepared information, data and recommendations which could assist the Government of Zambia in putting into effect the development of expanded educational broadcasting services for the formal education system in the country

The Loyalty of Employees in a Selected Company

V době globalizace a liberalizace se stále více prosazuje role zaměstnanců jako konkurenční výhody pro malé i velké organizace, ve kterých působí. Organizace může být schopnými zaměstnanci poháněna k větším úspěchům, když si udržuje cenné pracovníky a buduje loajalitu zaměstnanců. Tento výzkum je zaměřen na představení strategií a nástrojů, které napomáhají minimalizovat neloajalitu a fluktuaci zaměstnanců v DEX Innovation Centre. Při výzkumu byl využit nástroj Computer Assisted Web Interview (CAWI), který umožňuje vytvoření výzkumného dotazníku přístupného elektronickou cestou respondentům. Použity byly také nástroje Google formulář a Survey Monkey. Bylo provedeno dvojí šetření, a to průzkum zaměstnanecké angažovanosti a výstupní dotazování. Smyslem těchto šetření bylo přispět k udržení pracovníků v podniku, zlepšit pracovní prostředí, zvýšit spokojenost zaměstnanců a poskytnout srovnávací kritérium pro zajištění budoucího rozvoje podniku.In the era of globalization and liberalisation, employees are continuously proving to be competitive advantage for any organization they associate with being large or small. Therefore, an organization managed with competent employees can propel any business to greater heights by retaining valuable staff and developing employee loyalty. This research is aimed at proposing strategies and tools to aid in the minimization of employee disloyalty and turnover at DEX Innovation Centre. The research employed the use of the Computer Assisted Web Interview (CAWI), a research tool that involves the creation of a research questionnaire which is to be administered electronically to the respondents. The tool Google forms and Survey Monkey were also applied. Two surveys were created, an employee engagement survey and an exit questionnaire. The purpose of these questionnaires was to improve employee retention, workplace environment, increase employee satisfaction and provide a benchmark to ensure continued improvement in the company

Spatial and temporal variation of CO₂ efflux along a disturbance gradient in a miombo woodland in Western Zambia

Carbon dioxide efflux from the soil surface was measured over a period of several weeks within a heterogeneous Brachystegia spp. dominated miombo woodland in Western Zambia. The objectives were to examine spatial and temporal variation of soil respiration along a disturbance gradient from a protected forest reserve to a cut, burned, and grazed area outside, and to relate the flux to various abiotic and biotic drivers. The highest daily mean fluxes (around 12 mu mol CO2 m(-2) s(-1)) were measured in the protected forest in the wet season and lowest daily mean fluxes (around 1 mu mol CO2 m(-2) s(-1)) in the most disturbed area during the dry season. Diurnal variation of soil respiration was closely correlated with soil temperature. The combination of soil water content and soil temperature was found to be the main driving factor at seasonal time scale. There was a 75% decrease in soil CO2 efflux during the dry season and a 20% difference in peak soil respiratory flux measured in 2008 and 2009. Spatial variation of CO2 efflux was positively related to total soil carbon content in the undisturbed area but not at the disturbed site. Coefficients of variation of efflux rates between plots decreased towards the core zone of the protected forest reserve. Normalized soil respiration values did not vary significantly along the disturbance gradient. Spatial variation of respiration did not show a clear distinction between the disturbed and undisturbed sites and could not be explained by variables such as leaf area index. In contrast, within plot variability of soil respiration was explained by soil organic carbon content. Three different approaches to calculate total ecosystem respiration (R-eco) from eddy covariance measurements were compared to two bottom-up estimates of R-eco obtained from chambers measurements of soil-and leaf respiration which differed in the consideration of spatial heterogeneity. The consideration of spatial variability resulted only in small changes of R-eco when compared to simple averaging. Total ecosystem respiration at the plot scale, obtained by eddy covariance differed by up to 25% in relation to values calculated from the soil-and leaf chamber efflux measurements but without showing a clear trend

Food Sector Transformation and Standards in Zambia: Smallholder Farmer Participation and Growth in the Dairy Sector

Market liberalization in Zambia has led to a rapid and fundamental transformation of its dairy sector. Mainly through foreign direct investment and international partnerships, a new formal dairy sector, characterized by institutional, organizational and technological innovation, emerged from the ashes of abandoned government projects. Sensing the development opportunity that arose from an untapped milk supply potential in Zambia's traditional smallholder livestock production and a growing milk demand from the newly emerging formal dairy processing sector, numerous donor-funded smallholder dairy farmer support programs emerged. At the same time, in order to protect its domestic market as well as to be in a better position to enter demanding export markets, stakeholders from the private, public and NGO sector have recently joined forces to develop technical dairy product standards for Zambia based on the CODEX.Livestock Production/Industries,

A novel integration of a green power-to-ammonia to power system: Reversible solid oxide fuel cell for hydrogen and power production coupled with an ammonia synthesis unit

Renewable energy is a key solution in maintaining global warming below 2 °C. However, its intermittency necessitates the need for energy conversion technologies to meet demand when there are insufficient renewable energy resources. This study aims to tackle these challenges by thermo-electrochemical modelling and simulation of a reversible solid oxide fuel cell (RSOFC) and integration with the Haber Bosch process. The novelty of the proposed system is usage of nitrogen-rich fuel electrode exhaust gas for ammonia synthesis during fuel cell mode, which is usually combusted to prevent release of highly flammable hydrogen into the environment. RSOFC round-trip efficiencies of 41–53% have been attained when producing excess ammonia (144 kg NH3/hr) for the market and in-house consumption respectively. The designed system has the lowest reported ammonia electricity consumption of 6.4–8.21 kWh/kg NH3, power-to-hydrogen, power-to-ammonia, and power-generation efficiencies of 80%, 55–71% and, 64–66%

Seamless Variability Management With the Virtual Platform

Customization is a general trend in software engineering, demanding systems that support variable stakeholder requirements. Two opposing strategies are commonly used to create variants: software clone & own and software configuration with an integrated platform. Organizations often start with the former, which is cheap, agile, and supports quick innovation, but does not scale. The latter scales by establishing an integrated platform that shares software assets between variants, but requires high up-front investments or risky migration processes. So, could we have a method that allows an easy transition or even combine the benefits of both strategies? We propose a method and tool that supports a truly incremental development of variant-rich systems, exploiting a spectrum between both opposing strategies. We design, formalize, and prototype the variability-management framework virtual platform. It bridges clone & own and platform-oriented development. Relying on programming-language-independent conceptual structures representing software assets, it offers operators for engineering and evolving a system, comprising: traditional, asset-oriented operators and novel, feature-oriented operators for incrementally adopting concepts of an integrated platform. The operators record meta-data that is exploited by other operators to support the transition. Among others, they eliminate expensive feature-location effort or the need to trace clones. Our evaluation simulates the evolution of a real-world, clone-based system, measuring its costs and benefits.Comment: 13 pages, 10 figures; accepted for publication at the 43rd International Conference on Software Engineering (ICSE 2021), main technical trac

Capturing views of men, women and youth on agricultural biodiversity resources consumed in Barotseland, Zambia

This paper presents data and findings from focus group discussions in study communities selected by the CGIAR Research Program on Aquatic Agricultural Systems (AAS) in the Western Province of Zambia. The discussions focused on cultivated crops and vegetables collected from open fields and consumed as food. Participatory tools for agricultural biodiversity (agrobiodiversity) assessment were used to capture community perspectives on plant species and varietal diversity; factors influencing the availability and use of plants for food; unique, common and rare crop species cultivated in a community, identified through a four-cell analysis methodology; and core problems, root causes, effects and necessary actions to tackle them, using problem tree or situation analysis methods

Using machine learning to expound energy poverty in the global south: understanding and predicting access to cooking with clean energy

Efforts towards achieving high access to cooking with clean energy have not been transformative due to a limited understanding of the clean-energy drivers and a lack of evidence-based clean-energy policy recommendations. This study addresses this gap by building a high-performing machine learning model to predict and understand the mechanisms driving energy poverty - specifically access to cooking with clean energy. In a first-of-a-kind, the estimated cost of US14.5 to enable universal access to cooking with clean energy encompasses all the intermediate inputs required to build self-sufficient ecosystems by creating value-addition sectors. Unlike previous studies, the data-driven clean-cooking transition pathways provide foundations for shaping policy that can transform the energy and cooking landscape. Developing these pathways is necessary to increase people's financial resilience to tackle energy poverty. The findings also show the absence of a linear relationship between electricity access and clean cooking - evidencing the need for a rapid paradigm shift to address energy poverty. A new fundamental approach that focuses on improving and sustaining the financial capacity of households through a systems approach is required so that they can afford electricity or fuels for cooking.Engineering and Physical Sciences Research Council (EPSRC): EP/S023909/

Hydrogen technology adoption analysis in Africa using a Doughnut-PESTLE hydrogen model (DPHM)

The hydrogen economy requires the right conditions to produce hydrogen by sustainable routes and provide it to local and international markets for suitable applications. This study evaluated the political, economic, social, technological, legal, and environmental (PESTLE) conditions that can be instrumental in adopting hydrogen technologies most effectively by encapsulating aspects relevant to key stakeholders from hydrogen technology developers through to end-users. For instance, the analysis has shown that countries within a government effectiveness index of 0.5 and −0.5 are leading the planning of hydrogen economies through strategic cooperation with hydrogen technology developers. Furthermore, the combination of a Doughnut and PESTLE analysis created a novel approach to assessing the adoption of hydrogen technologies while evaluating the impact of the hydrogen economy. For instance, the estimated ammonia demand in 2050 and subsequent anthropogenic nitrogen extraction rate will be about two and a half times more than the 2009 extraction rate