Basic Operation Unit Research Articles

An infrastructure for cooperative applications based on conventional database transactions

'Computer-Supported Cooperative Work' (CSCW) is a young, interdisciplinary research area considering applications with strong demands on multiple fields of computer technology, e.g., distributed systems and networks, or multi-media systems. In this paper, we will be focusing on the information-sharing aspect and the corresponding activity-control aspect. Employing database systems for the management of shared data means dealing with conventional transactions. Crucial issues of the classical transaction concept are the isolated execution and the underlying notion of consistency. Whereas consistency support is necessary for any multi-user application, strict isolation seems to contradict the cooperation issue (release of preliminary data). As a consequence, the transaction concept plays a key role due to consistency management, but cooperation control must be supported by additional facilities. Therefore, we exploit the classical transaction as the basic operational unit in the infrastructure we propose for cooperative applications. Transactions are well suited for the execution of the elementary actions into which the work of a cooperating user can be decomposed. Beside these elementary actions, further types of activities can be observed in cooperative work arrangements. In order to give a comprehensive activity support, our infrastructure provides several abstractional layers: classical transactions, version manipulations, tool invocations, workflow executions and explicit cooperation control actions. Multiple possibilities of interplay between these layers make this infrastructure feasible to different classes of cooperative applications.

Automated Identification of Diatoms

Instrumentation permitting rapid automated identification of diatoms to be used in an environmental quality control system is described. A micro-optical processor, using input from an interference contrast microscope coherently illuminated by a Helium-Neon laser or an Argon laser, is the basic operational unit. Some of the options and problems in automated identification are discussed. (Accepted for publication 4 August 1981)

Paleogeologic and Quantitative Lithofacies Analysis, Simpson Group, Oklahoma

The Joins, Oil Creek, McLish, Tulip Creek, Bromide, and Corbin Ranch Formations of the Simpson Group were correlated throughout the subsurface of Oklahoma in order to (1) establish formational equivalents between measured surface sections in the Arbuckle and southwestern Ozark Mountain regions, (2) determine erosional or depositional limits of each of the formations, (3) illustrate suspected existing interformational regional disconformities, and (4) provide basic operational units from which thickness and gross lithologic data could be derived quantitatively for construction of a series of isopach and facies maps. A technique of lithofacies expression based on the classifying function (D-function) is advanced. The method was conceived by Pelto (1954) as a means of mapping multicomponent systems alternative to methods devised by Krumbein and Sloss (1951). With one exception (Forgotson, 1960, p. 88), the classifying function technique generally has not been utilized in practical application. Simplicity of map design, compared with corresponding composite maps based on percentages and ratios, the extreme rapidity with which the maps are constructed, and the facility of tectonic and environmental interpretation justify recognition of this method as a usable mapping tool. Detailed subsurface correlation and faunal evidence substantiate the thesis that the thin lower Tyner-Burgen sequence cropping out along the southwestern flank of the Ozark uplift is equivalent to at least the lower part of the thick Oil Creek Formation of the Arbuckle region. The middle Tyner shale is considered by the writer to be McLish, and the upper Tyner dolomitic limestone and Fite Limestone are herein correlated conjunctively with the Corbin Ranch Formation. A distinct break in sedimentation between the upper and middle Tyner beds represents a significant hiatus during which time Tulip Creek and Bromide strata were eroded from the Ozark area. The Simpson Group contains many interformational unconformities and onlap pinchouts of both regional and local magnitude. Intraformational discontinuity on a lesser scale is suspected but not confirmed. The Joins and Tulip Creek Formations are limited essentially to the southern half of Oklahoma as a result of non-deposition and only locally by erosion. The Tulip Creek and superjacent Bromide Formation are absent from eastern Oklahoma owing to erosion from the Ozark uplift in Black Riveran time. Absence of the Corbin Ranch Formation locally below Viola strata in the Arbuckle and eastern Wichita Mountains is evidence that minor incipient tectonism of these elements occurred in post-early Trenton time.