Observations of Hierarchical Solar-Type Multiple Star Systems

Twenty multiple stellar systems with solar-type primaries were observed at high angular resolution using the PALM-3000 adaptive optics system at the 5 m Hale telescope. The goal was to complement the knowledge of hierarchical multiplicity in the solar neighborhood by confirming recent discoveries by the visible Robo-AO system with new near-infrared observations with PALM-3000. The physical status of most, but not all, of the new pairs is confirmed by photometry in the Ks band and new positional measurements. In addition, we resolved for the first time five close sub-systems: the known astrometric binary in HIP 17129AB, companions to the primaries of HIP 33555, and HIP 118213, and the companions to the secondaries in HIP 25300 and HIP 101430. We place the components on a color-magnitude diagram and discuss each multiple system individually.Comment: Accepted to Astronomical Journa

Hierarchical Description of Software System Organization ; CU-CS-120-77

Constructs for hierarchically describing the organization of large-scale software systems are presented. The constructs allow the explicit specification of subsystem sharing. Descriptions using these constructs are therefore not necessarily tree-like and hence are frequently more natural and clear. The constructs were developed as part of a language for describing a system’s design, as opposed to its implementation. The efficacy of the constructs is argued with respect to this description task and the constructs are compared to similar ones available in programming languages

A Description Scheme to Aid the Design of Collections of Concurrent Processes ; CU-CS-118-77

A modelling scheme is presented which allows the abstract description of a collection of concurrent processes (a subsystem). A model in the scheme provides a specification of a subsystem which describes its behavior in relation to other subsystems but hides the subsystem’s operational detail. A model consists of a definition of the subsystem’s interface, a procedural definition of the legal usage of the interface and a non-procedural description of the legal uses of the subsystem over time. Models in the scheme are rigorous, unambiguous specifications of the components within a software system. The models may be used to guide the implementation of the components or the formulate arguments as to the appropriateness of a system’s design

An Event-Based Design Methodology Supported by DREAM ; CU-CS-140-78

A methodology for the architectural design of software systems is composed of three interrelated facilities. First, there must be some means of capturing the requirements for the system in some primarily non-procedural specification. Second, there must be some means for describing potential modularizations of the system in some primarily pseudo-procedural design which captures the essential detail concerning the modules; interfaces and their interactions. Finally, there must be some means of determining whether a system design appropriately meets the system specification. In this paper, we present a design methodology based on the use of event and event sequence descriptions. We first give a brief definition of the Design Realization, Evaluation and Modelling (DREAM) system and its description language as they relate to an event-based design method. Then we define the design method and give a simple example

Software Development Environments: Present and Future ; CU-CS-170-80

Computerized environments which facilitate the development of appropriately functioning software systems are discussed. Their current status is reviewed and several trends exhibited by their history are identified. A number of principles, some at (slight) variance with the historical trends, are suggested and it is argued that observance of these principles is critical to achieving truly effective and efficient software development support environments