Formal Transformations from Graphically-Based Object-Oriented Representations to Theory-Based Specifications

Formal software specification has long been touted as a way to increase the quality and reliability of software; however, it remains an intricate, manually intensive activity. An alternative to using formal specifications is to use graphically-based, semi-formal specifications such as those used in many object-oriented specification methodologies. While semi-formal specifications are generally easier to develop and understand, they lack the rigor and precision of formal specification techniques. The basic premise of this investigation is that formal software specifications can be constructed using correctness preserving transformations from graphically-based object-oriented representations. In this investigation, object-oriented specifications defined using Rumbaugh\u27s Object Modeling Technique (OMT) were translated into algebraic specifications. To ensure the correct translation of graphically-based OMT specifications into their algebraic counterparts, a formal semantics for interpreting OMT specifications was derived and an algebraic model of object-orientation was developed. This model defines how object-oriented concepts are represented algebraically using an object-oriented algebraic specification language O-SLANG. O-SLANG combines basic algebraic specification constructs with category theory operations to capture internal object class structure as well as relationships between classes. Next, formal transformations from OMT specifications to O-SLANG specifications were defined and the feasibility of automating these transformations was demonstrated by the development of a proof-of-concept system

Associations of cardiac structure with obesity, blood pressure, inflammation, and insulin resistance in African-American adolescents.

To determine if obesity, blood pressure (BP), markers of inflammation, and insulin resistance are associated with cardiac structure in African-American adolescents, a cross-sectional study was performed on a cohort oversampled for high BP and obesity. Measurements included the following: anthropometrics, BP, homeostasis model assessment (HOMA) to assess insulin resistance, high-sensitivity C-reactive protein, and plasma adipokines (adiponectin, interleukin-6, plasminogen activator inhibitor-1). Echocardiogram measurements were left-ventricular mass index (LVMI) (g/m(2.7)), LV relative wall thickness (LVRWT), left-atrial diameter index [LADI (mm/m)], and LV diastolic time intervals. LADI (r (2) = 0.25) was associated with body mass index (BMI) systolic BP (SBP) and female sex. LVMI (r (2) = 0.35) variation was associated with BMI SBP, heart rate, age, and male sex. LVRWT (r (2) = 0.05) was associated with HOMA. Tissue diastolic intervals were not associated with any risk factor. Inflammatory markers and adipokines were associated with BMI but were not independently associated with any echocardiographic measures. In African-American adolescents, BMI and SBP, but not inflammatory markers or adipokines, are important correlates of LA size and LVM

Specifying Agent Behavior as Concurrent Tasks: Defining the Behavior of Social Agents

Approved for public release; distribution unlimited Software agents are currently the subject of much research in many interrelated fields. While much of the agent community has concentrated on building exemplar agent systems, defining theories of agent behavior and inter-agent communications, there has been less emphasis on defining the techniques required to build practical agent systems. While many agent researchers refer to tasks performed by roles within a multiagent system, few really define the what they mean by tasks. We believe that the definition of tasks is critical in order to completely define what an agent within a multiagent system. Tasks not only define the types of internal processing an agent must do, but also how interactions with other agents relate to those internal processes. In this report, we define concurrent tasks, which specify a single thread of control that defines a task that the agent can perform and integrates inter-agent as well as intra-agent interactions. We typically think of concurrent tasks as defining how a role decides what actions to take, not necessarily what the agent does. This is an important distinction when talking about agents since hard-coding specific behavior may not be the ideal case. Often agents incorporate the concept of plans and planning t

Engineering Organization-based Multiagent Systems

Abstract. In this paper, we examine the Multiagent Systems Engineering (MaSE) methodology and its applicability to developing organization-based multiagent systems, which are especially relevant to context aware systems. We discuss the inherent shortcomings of MaSE and then present our approach to modeling the concepts required for organizations including goals, roles, agents, capabilities, and the assignment of agents to roles. Finally, we extend MaSE to allow it to overcome its inherent shortcomings and capture the organizational concepts defined in our organization metamodel.