Evaluating two ways of calculating priorities in requirements hierarchies - An experiment on hierarchical cumulative voting

When developing large-scale software systems, there is often a large amount of requirements present, and they often reside on several hierarchical levels. In most cases, not all stated requirements can be implemented into the product due to different constraints, and the requirements must hence be prioritized. As requirements on different abstraction levels shall not be compared, prioritization techniques that are able to handle multi-level prioritization are needed. Different such techniques exist, but they seem to result in unfair comparisons when a hierarchy is unbalanced. In this paper, an empirical experiment is presented where an approach that compensate for this challenge is evaluated. The results indicate that some form of compensation is preferred, and that the subjects’ preference is not influenced by the amount of information given.     

Oxygen barrier properties of thermoformed trays manufactured with different drawing methods and drawing depths

A comparison was made of oxygen barrier properties and wall thickness distribution of different thermoformed trays. The thermoformed trays were manufactured with three drawing depths and two different thermoforming methods; with and without plug‐assist. Four different polymer combinations were evaluated. The oxygen transmission rate (OTR) [cm³/(package/day)] was measured at three conditions (23°C/50% relative humidity (RH) with 0% RH inside, 6°C/80% RH with 0% RH inside, and 6°C/80% RH with 100% RH inside. Wall thickness was measured at five different positions in the trays. In general, temperature had more influence on the oxygen transmission rate (OTR) than the humidity. The OTR in the packages increased with increasing drawing depth, but the increase was not linear. Other effects besides thinning, such as orientation, may have influenced the OTR, since the relationship between OTR, given as cm³/(m²/day), and the drawing depth was not linear. Plug‐assisted thermoforming only had an effect on the OTR in trays with 70 mm drawing depth made of 600 µm thick laminate of PP/PE, which was probably due to exceeding the maximum drawing depth of this material. There was no correlation between the OTR value in the packages and the wall thickness in either of the positions, but a quite high correlation between the drawing depth and the relative wall thickness in all measured positions was observed. Copyright © 2004 John Wiley & Sons, Ltd.     

An Event Algebra Extension of the Triggering Mechanism in a Component Model for Embedded Systems

In this article we present how the component triggering in SaveCCM, a component model intended for embedded vehicular systems, can be extended by means of an event algebra. The extension allows components to be triggered by complex event patterns, and not only by clock signals or single external events.Separating the detection of triggering conditions from the definition of the triggered services permits more general components and thus improves component reusability. Providing event detection mechanisms within the component model means that triggering conditions are explicitly available for system analysis at design time.An event algebra is used to define the complex triggering conditions. This algebra has a relatively simple declarative semantics and well documented algebraic properties, which facilitates formal and informal reasoning about the system. The algebra also ensures that detection of triggering conditions can be efficiently implemented with limited resources, which is critical in embedded applications.     

Assessment of manual assembly complexity: a theoretical and empirical comparison of two methods

There are several theoretical methods for assessment of assembly complexity but there are few practically applicable methods. One of the methods, CompleXity Index (CXI), aims at assessing operators’ perception of manual assembly complexity in running production. Another recently developed method, Basic Assembly Complexity (CXB) is intended for predictive assessment of basic manual assembly complexity in early product and production development. Both CXI and CXB aim to improve assembly conditions for operators, reduce assembly-related errors and the costs for corrective measures as well as increase assembly quality although in different ways and at different organisational levels and life cycle stages. The purpose of this study was to compare the two methods to obtain feedback and learn from operators experience in order to develop better predictive assessment criteria. The method comparison showed that about 50% of the CXB assessment approaches were similar to CXI but other covered different aspects. In comparison of the complexity values of the methods no significant results were obtained. However, some CXI issues that were not taken into account in CXB should be considered. CXB and CXI could be used in conjunction but further assessment criteria are probably needed.     

Proactive assessment of basic complexity in manual assembly: development of a tool to predict and control operator-induced quality errors

A major challenge for manufacturing companies today is to manage a huge amount of product variants and build options at the same time in manufacturing engineering and in production. The overall complexity and risk of quality errors in manual assembly will increase placing high demands on the operators who must manage many different tasks in current production. Therefore, methods for decreasing and controlling assembly complexity are urgent because managing complex product and installation conditions will result in distinct competitive advantages. The objective of this paper is to present a method for predictive assessment of basic manual assembly complexity and explain how included complexity criteria were arrived at. The verified method includes 16 high complexity and 16 low complexity criteria to aid designers in preventing costly errors during assembly and create good basic assembly conditions in early design phases of new manufacturing concepts.     

Countering the “dam effect”: the case for architecture and governance in developing country health information systems

ABSTRACT

This paper presents a case for enterprise architecture (EA) and IT governance for driving techno-organizational change and coordination of health information systems (HISs) in developing countries. We support our claim with analyses of a large-scale electronic HIS in Ethiopia by tracing the logic of actors’ decisions and conduct within and beyond the organizational boundaries of the Ethiopian Federal Ministry of Health to understand how the information system innovation process is designed, legitimized and imposed by internal and external organizational forces. In the absence of formalized institutional arrangements throughout the HIS development and implementation, an international development agency fills a key gap forming an obligatory passage point which we conceptualize as “the dam effect.” Drawing on actor-network theory, we identify three important implications of EA and IT governance: (1) to help achieve an alignment of interests within the enterprise; (2) to serve as a tool for protecting the interests of the enterprise in external negotiations; and (3) to serve as a pragmatic approach to carrying out techno-organizational change.     

Lifting inter-app data-flow analysis to large app sets

Mobile apps process increasing amounts of private data, giving rise to privacy concerns. Such concerns do not arise only from single apps, which might—accidentally or intentionally—leak private information to untrusted parties, but also from multiple apps communicating with each other. Certain combinations of apps can create critical data flows not detectable by analyzing single apps individually. While sophisticated tools exist to analyze data flows inside and across apps, none of these scale to large numbers of apps, given the combinatorial explosion of possible (inter-app) data flows. We present a scalable approach to analyze data flows across Android apps. At the heart of our approach is a graph-based data structure that represents inter-app flows efficiently. Following ideas from product-line analysis, the data structure exploits redundancies among flows and thereby tames the combinatorial explosion. Instead of focusing on specific installations of app sets on mobile devices, we lift traditional data-flow analysis approaches to analyze and represent data flows of all possible combinations of apps. We developed the tool Sifta and applied it to several existing app benchmarks and real-world app sets, demonstrating its scalability and accuracy.     

Engineering of a metal coordinating site into human glutathione transferase M1-1 based on immobilized metal ion affinity chromatography of homologous rat enzymes

Rat glutathione transferase (GST) 3-3 binds to Ni(II)-iminodiaceticacid (IDA)-agarose, whereas other GSTs that are abundant inrat liver do not bind to this immobilized metal ion affinitychromatography (IMAC) adsorbent Rat GST 3-3 contains two superficiallylocated amino acid residues, His84 and His85, that are suitablypositioned for coordination to Ni(II)-IDA-agarose. This particularstructural motif is lacking in GSTs that do not bind to theIMAC matrix. Creation of an equivalent His-His structure inthe homologous human GST M1-1 by protein engineering affordeda mutant enzyme that displays affinity for Ni(II)-IDA-agarose,in contrast to the wild-type GST M1-1. The results identifya distinct site that is operational in IMAC and suggest an approachto the rational design of novel integral metal coordinationsites in proteins.     

A simple route towards high-concentration surfactant-free graphene dispersions

A simple solvent exchange method is introduced to prepare high-concentration and surfactant-free graphene liquid dispersion. Natural graphite flakes are first exfoliated into graphene in dimethylformamide (DMF). DMF is then exchanged by terpineol through distillation, relying on their large difference in boiling points. Graphene can then be concentrated thanks to the volume difference between DMF and terpineol. The concentrated graphene dispersions are used to fabricate transparent conductive thin films, which possess comparable properties to those prepared by more complex methods.     

The effect of counter ions and substrate material on the growth and morphology of poly(3,4-ethylenedioxythiophene) films: Towards the application of enzyme electrode construction in biofuel cells

Poly(3,4-ethylenedioxythiophene) (PEDOT) films, with Cl^?, NO₃^?, poly(styrene sulfonate) (PSS^?) or carbon nanotubes (CNTs) as counter ions, were electrochemically deposited onto indium tin oxide (ITO) glass from aqueous electrolyte. PEDOT film, with tetrafluoroborate anions (BF₄^?) as counter ions, was also electrochemically deposited on ITO glass from a propylene carbonate-based electrolyte. The effect of counter ions on the morphology of PEDOT films was demonstrated by the characterizations with scanning electron microscope (SEM). Different carbon-based materials were explored as the substrate materials for PEDOT film generation in electropolymerization, including carbon ink paper, carbon paper, carbon felt, and reticulated vitreous carbon foam (RVC foam). The micro-structure and the surface morphology of the resulted PEDOT films were imaged with SEM. The elemental analysis of the films was performed with energy dispersive X-ray analysis (EDAX). The topography of the PEDOT films was characterized using confocal white light microscopy (COM). A biofuel cell cathode was prepared by immobilization of Trametes Hirsuta laccase (Th-laccase) in PEDOT and the performance of the electrode towards oxygen reduction was examined by chronoamperomentric measurements.