Strengthening MDA by Drawing from the Living Systems Theory

OMGs Model Driven Architecture initiative comes at a time where information system builders and integrators have realized that application design and thus application interoperability is not primarily a technology issue but is about understanding different types of systems, involving different professional and scientific disciplines. Understanding requires thinking and thinking is modeling. Hence, MDA provides a framework for modeling systems, especially those systems that are relevant in the context of IT-system integration within and across company boundaries. However, model correspondence, i.e., relations and transformations among models and views in a consistent way, presents a challenging problem for MDA. Bridging of disciplines was also a key motivation for the systems science communities, and in particular for the life sciences. A widely accepted theory about all living systems was developed by J. G. Miller the Living Systems Theory. His theory is striking because the basic concepts and principles are applicable at all levels, i.e., for all types of livings systems, from a cell to a supranational organization. The Living Systems Theory thus provides a good basis for consistently relating different systems and different views. In this paper, we will show how the living systems theory can be used to go about the problem of model correspondences. In particular, we suggest that MDA explicitly use the notions of a model reality with organizational levels based on a modeling ontology that is derived from the living systems theory

Foundations of systems and properties:methodological support for modeling properties of software-intensive systems

Engineering of software-intensive systems is concerned with the creation and evolution of systems that shall exhibit desired properties in their execution as well as development environment. In this context, the motivation of this thesis, derived from current development practice, was twofold. Firstly, software development methods are increasingly required to extend their scope of applicability towards systems engineering. As a consequence, their modeling approaches must be able to cope with a larger diversity of systems and consequently a larger diversity of properties. But these approaches still need to provide a smooth transition to software modeling. Secondly, non-functional properties, which are largely a result of this implicit systems scope, play a major role in the way we design our software-intensive systems. The conceptual aids of current development methods, however, are still less mature in their explicit support for non-functional properties compared with their ability to support functional ones. The principal objective of this thesis is to contribute toward an improved model-based treatment of non-functional properties in development methods. Because we cannot discuss properties independently of the objects they are ascribed to, this objective amounts to a progression from modeling of software and its properties to modeling of interrelated systems and their properties. To address this aim a philosophy of properties and systems is proposed. The philosophy is expressed as a holistic conceptual model of properties and/of systems. It is complemented with some basic rules, which we call tenets. Tenets formulate how we use the philosophical knowledge. The conceptual model offers the foundations for a more generalized understanding of those fundamentally different types of systems and different types of properties that are relevant in software-intensive systems engineering. The generality of our holistic model draws the benefits from our investigations in the areas of systems science, cognitive science, and basic philosophy. The model helps to scrutinize and make sense of the large amount of data in the literature about "non-functional" issues in software engineering. The model is applicable in the derivation of methodological building blocks that can be incorporated into development methods. The building blocks include (a) a general model to discover stakeholders and properties for a given system, (b) a principled manner to trace the fundamentally different types of properties through hierarchies of systems, and (c) a proposal for the representation of systems, their properties and property traces in the UML. The concrete application of the gained knowledge to software engineering results in a proposal for a context-sensitive, customizable quality attribute model. It also results in a proposal on how to structure quality descriptions of software components. In order for such descriptions to be standardized and possibly tool-automated, this thesis proposes to utilize the Reusable Asset Specification and suggests alternatives for its XML-based representation

An Automated, Language-Based Approach to the Creation of Component Libraries

A major promise of component-based software engineering is the reduction of application development time and costs by reusing software components. The existence of and access to component libraries, as well as the ability to build such libraries in the first place, is therefore key in a component-based development infrastructure to facilitate the envisioned reuse. We believe that the future demand for component libraries will increase substantially because many companies are about to adopt the software product line ideas. Due to the lack of a general standard for component libraries and because of the restrictions of existing ones, it is very often the case that new reuse libraries are written from scratch to fit a user's specific requirements. An additional problem is the size and the focus of (existing) component libraries or component repositories. With an increasing size and a broadening focus of the library it becomes harder to retrieve the "right" components due to more complex classification structures, which hinders effective reuse. This will lead to a large number of specific libraries, rather than to the global all-encompassing single one. This work introduces a component library description language, which allows for the definition of a component library, its provided functionality, and its associated semantics on a high level of abstraction. The language compiler uses those definitions made in the (XML-based) language to automatically generate a component library, which is a user-defined, customized application, including a web-based user interface and a persistent storage facility to store the components handled by the library. The language approach allows for the rapid development of domain specific component libraries in a time and cost efficient manner and therefore supports the need for fast creation of reuse libraries with minimal up-front investment

Maximizing efficiency of rumen microbial protein production.

Rumen microbes produce cellular protein inefficiently partly because they do not direct all ATP toward growth. They direct some ATP toward maintenance functions, as long-recognized, but they also direct ATP toward reserve carbohydrate synthesis and energy spilling (futile cycles that dissipate heat). Rumen microbes expend ATP by vacillating between (1) accumulation of reserve carbohydrate after feeding (during carbohydrate excess) and (2) mobilization of that carbohydrate thereafter (during carbohydrate limitation). Protozoa account for most accumulation of reserve carbohydrate, and in competition experiments, protozoa accumulated nearly 35-fold more reserve carbohydrate than bacteria. Some pure cultures of bacteria spill energy, but only recently have mixed rumen communities been recognized as capable of the same. When these communities were dosed glucose in vitro, energy spilling could account for nearly 40% of heat production. We suspect that cycling of glycogen (a major reserve carbohydrate) is a major mechanism of spilling; such cycling has already been observed in single-species cultures of protozoa and bacteria. Interconversions of short-chain fatty acids (SCFA) may also expend ATP and depress efficiency of microbial protein production. These interconversions may involve extensive cycling of intermediates, such as cycling of acetate during butyrate production in certain butyrivibrios. We speculate this cycling may expend ATP directly or indirectly. By further quantifying the impact of reserve carbohydrate accumulation, energy spilling, and SCFA interconversions on growth efficiency, we can improve prediction of microbial protein production and guide efforts to improve efficiency of microbial protein production in the rumen

Ecology and application of haloalkaliphilic anaerobic microbial communities

Haloalkaliphilic microorganisms that grow optimally at high-pH and high-salinity conditions can be found in natural environments such as soda lakes. These globally spread lakes harbour interesting anaerobic microorganisms that have the potential of being applied in existing technologies or create new opportunities. In this review, we discuss the potential application of haloalkaliphilic anaerobic microbial communities in the fermentation of lignocellulosic feedstocks material subjected to an alkaline pre-treatment, methane production and sulfur removal technology. Also, the general advantages of operation at haloalkaline conditions, such as low volatile fatty acid and sulfide toxicity, are addressed. Finally, an outlook into the main challenges like ammonia toxicity and lack of aggregation is provided.This work was performed in the TTIW- cooperation framework of Wetsus, European Centre of Excel- lence for Sustainable Water Technology (www.wetsus.nl). Wetsus is funded by the Dutch Ministry of Economic Affairs, the European Union Regional Development Fund, the Province of Fryslân, the City of Leeuwarden and the EZ/Kompas program of the“ Samenwerkingsverband Noord-Nederland”. The authors would like to thank the participants of the research theme "Sulfur", namely Paqell, for fruitful discussions and financial suppor

On Quality Attribute Based Software Engineering

For a software system to be perceived as a success, or even just as properly functioning, many quality attributes, besides functionality, need to be at an acceptable level. However, current software development processes focus on the functional aspects of a system to be developed. They hardly help to systematically engineer for quality attributes other than functionality. It is a system`s architecture by which such quality requirements are satisfied. In particular, software components are an incarnation of architectural means, which have come into being to better cope with the variety of quality aspects of software systems. Unfortunately, architectural artifacts appear somewhat magically sometimes, and so do components. Hence, components are not a major extension to OO in the programming language or conceptual modeling sense, but a basis to address many of the quality requirements, be they discernable or non-discernable at system runtime. CBSE, being the discipline of engineering with components, is a promising basis to more explicitly and systematically design with and for quality attributes. After defining the context and classifying quality attributes, we first illustrate the important relationship of quality attributes to use case realizations. Second, we argue for components as the fulcrum point for the realization of functional and extra-functional roles. Third, we identify ongoing research directions that we consider conducive towards a software engineering process that supports the design for functional and extra-functional requirements