The case against a positivist philosophy of requirements engineering

Requirements engineering is a field with a heavy practical emphasis and for the most part is quite rightly unconcerned with philosophical reflection. However, there have been exceptions. Philosophical arguments are important because they can be used to powerful effect, facilitating explicit debate on views that may previously have been implicit, and shaping the direction of thought and research within the field. Several cases from both requirements engineering and software engineering have given prominence to the philosophy of positivism. This paper will outline arguments against such a view.

Metazoans and Intrinsic Apoptosis: An Evolutionary Analysis of the Bcl-2 Family

The B-cell lymphoma-2 (Bcl-2) family is a group of genes regulating intrinsic apoptosis, a process controlling events such as development, homeostasis and the innate and adaptive immune responses in metazoans. In higher organisms, Bcl-2 proteins coordinate intrinsic apoptosis through their regulation of the integrity of the mitochondrial outer membrane; this function appears to have originated in the basal metazoans. Bcl-2 genes predate the cnidarian-bilaterian split and have been identified in porifera, placozoans and cnidarians but not ctenophores and some nematodes. The Bcl-2 family is composed of two groups of proteins, one with an α-helical Bcl-2 fold that has been identified in porifera, placozoans, cnidarians, and almost all higher bilaterians. The second group of proteins, the BH3-only group, has little sequence conservation and less well-defined structures and is found in cnidarians and most bilaterians, but not porifera or placozoans. Here we examine the evolutionary relationships between Bcl-2 proteins. We show that the structures of the Bcl-2-fold proteins are highly conserved over evolutionary time. Some metazoans such as the urochordate Oikopleura dioica have lost all Bcl-2 family members. This gene loss indicates that Bcl-2 regulated apoptosis is not an absolute requirement in metazoans, a finding mirrored in recent gene deletion studies in mice. Sequence analysis suggests that at least some Bcl-2 proteins lack the ability to bind BH3-only antagonists and therefore potentially have other non-apoptotic functions. By examining the foundations of the Bcl-2 regulated apoptosis, functional relationships may be clarified that allow us to understand the role of specific Bcl-2 proteins in evolution and disease.     

Estimation of human dose of staphylococcal enterotoxin A from a large outbreak of staphylococcal food poisoning involving chocolate milk

An outbreak of gastroenteritis in a school district in the United States was determined to be staphylococcal food poisoning due to 2% chocolate milk containing staphylococcal enterotoxin A (SEA). Twelve one-half pint (approx 0.28 l) cartons of the 2% chocolate milk from this outbreak were analyzed for the quantity of SEA present in the milk. The amount of SEA in the cartons varied from 94 to 184 ng with the average being 144 ng (mean = 139 +/- 45). The attack rate for vomiting among those who consumed more than one carton was greater (38.3%) than among those who consumed only one carton (31.5%) with the highest attack rate among those who consumed three or more cartons (44.4%).     

A 20 K GaAs array with 10 K of embedded SRAM

A 20000-gate GaAs array with 10 K of embedded RAM is presented. The array contains eight scannable fully registered 256×256 RAM macros which have a minimum cycle time of 3.5 ns. The RAM features a scan mode, which can be used to configure the registers into a serial shifter. There is also a RAM test mode which allows independent functional and speed testing of all eight RAMs, easing the task of RAM verification for a given user personalization. The RAM array was fabricated using an advanced high-performance GaAs semiconductor E /D MESFET process featuring self-aligned gates and requiring only 12 masks. Introductory discussion of the Vitesse GaAs process, basic GaAs MESFET characteristics, and GaAs circuit design are provided. The gate array portion contains 20736 user-configurable cells with 10-ps gate delays which are tailored for direct-coupled FET logic (DCFL). The I/O can be personalized for ECL, TTL, or GaAs levels. There are 392 pads on the 13.8-mm×7.7-mm die with a maximum of 256 used for signal I/O. The RAM array is packaged in a multilayer ceramic 344-pin leaded chip carrier (LDCC). Typical power dissipation at 80% utilization is 14 W     

Autonomy and Common Ground in Human-Robot Interaction: A Field Study

The use of robots, especially autonomous mobile robots, to support work is expected to increase over the next few decades. However, little empirical research examines how users form mental models of robots, how they collaborate with them, and what factors contribute to the success or failure of human-robot collaboration. A two-year observational study of a collaborative human-robot system suggests that the factors disrupting the creation of common ground for interactive communication change at different levels of robot autonomy. Our observations of users collaborating with the remote robot showed differences in how the users reached common ground with the robot in terms of an accurate, shared understanding of the robot's context, planning, and actions - a process called grounding. We focus on how the types and levels of robot autonomy affect grounding. We also examine the challenges a highly autonomous system presents to people's ability to maintain a shared mental model of the robot     

Properties of a thermal-processed beverage prepared from roasted partially defatted peanuts

The effects of two thermal processing methods on physical and sensory properties of a beverage prepared from finely ground, partially defatted roasted peanuts ( Arachis hypogaea ) were determined. Samples were either bottle-processed at 72 °C for 2 min or 111 °C for 8 min after homogenizing at 72 °C, or kettle-pasteurized for 2 min at 72, 77 or 82 °C before homogenizing at 72, 77 or 82 °C, respectively. Harsher thermal processing parameters increased the suspension stability and viscosity of bottle-processed beverage by 175 and 87%, respectively, but had no influence on kettle-pasteurized beverage. Total solids (%) and colour were not adversely affected by thermal processing. Beverage which was kettle-pasteurized and homogenized at 72 °C had low viscosity (6.1–8.4 cps), typical roasted peanut flavour and little or no chalky mouthfeel, irrespective of whether carrageenan (stabilizer) or mono-diglyceride (emulsifier) were added to the formulation. Kettle-pasteurizing before homogenizing (20.7 × 10⁶ Pa) showed potential for producing beverages with physical and sensory attributes similar to commercial cow milk products.