Selection Power and Selection Labor for Information Retrieval

This study examines the relation between selection power and selection labor for information retrieval (IR). It is the first part of the development of a labor theoretic approach to IR. Existing models for evaluation of IR systems are reviewed and the distinction of operational from experimental systems partly dissolved. The often covert, but powerful, influence from technology on practice and theory is rendered explicit. Selection power is understood as the human ability to make informed choices between objects or representations of objects and is adopted as the primary value for IR. Selection power is conceived as a property of human consciousness, which can be assisted or frustrated by system design. The concept of selection power is further elucidated, and its value supported, by an example of the discrimination enabled by index descriptions, the discovery of analogous concepts in partly independent scholarly and wider public discourses, and its embodiment in the design and use of systems. Selection power is regarded as produced by selection labor, with the nature of that labor changing with different historical conditions and concurrent information technologies. Selection labor can itself be decomposed into description and search labor. Selection labor and its decomposition into description and search labor will be treated in a subsequent article, in a further development of a labor theoretic approach to information retrieval.

Linguistics and Information Theory: Analytic advantages

The analytic advantages of central concepts from linguistics and information theory, and the analogies demonstrated between them, for understanding patterns of retrieval from full-text indexes to documents are developed. The interaction between the syntagm and the paradigm in computational operations on written language in indexing, searching, and retrieval is used to account for transformations of the signified or meaning between documents and their representation and between queries and documents retrieved. Characteristics of the message, and messages for selection for written language, are brought to explain the relative frequency of occurrence of words and multiple word sequences in documents. The examples given in the companion article are revisited and a fuller example introduced. The signified of the sequence stood for, the term classically used in the definitions of the sign, as something standing for something else, can itself change rapidly according to its syntagm. A greater than ordinary discourse understanding of patterns in retrieval is obtained.

Analogies between linguistics and information theory

An analogy is established between the syntagm and paradigm from Saussurean linguistics and the message and messages for selection from the information theory initiated by Claude Shannon. The analogy is pursued both as an end itself and for its analytic value in understanding patterns of retrieval from full text systems. The multivalency of individual words when isolated from their syntagm is contrasted with the relative stability of meaning of multi-word sequences, when searching ordinary written discourse. The syntagm is understood as the linear sequence of oral and written language. Saussureâ??s understanding of the word, as a unit which compels recognition by the mind, is endorsed, although not regarded as final. The lesser multivalency of multi-word sequences is understood as the greater determination of signification by the extended syntagm. The paradigm is primarily understood as the network of associations a word acquires when considered apart from the syntagm. The restriction of information theory to expression or signals, and its focus on the combinatorial aspects of the message, is sustained. The message in the model of communication in information theory can include sequences of written language. Shannonâ??s understanding of the written word, as a cohesive group of letters, with strong internal statistical influences, is added to the Saussurean conception. Sequences of more than one word are regarded as weakly correlated concatenations of cohesive units.

Prograded Holocene beach-ridges with superimposed dunes in north-east Ireland: mechanisms and timescales of fine and coarse beach sediment decoupling and deposition

Two depositional models to account for Holocene gravel-dominated beach ridges covered by dunes, occurring on the northern coast of Ireland, are considered in the light of infrared-stimulated luminescence ages of sand units within beach ridges, and 14C ages from organic horizons in dunes. A new chronostratigraphy obtained from prograded beach ridges with covering dunes at Murlough, north-east Ireland, supports a model of mesoscale alternating sediment decoupling (ASD) on the upper beach, rather than macroscale sequential sediment sourcing to account for prograded beach ridges and covering dunes. The ASD model specifies storm or fair-weather sand beach ridges forming at high-tide positions (on an annual basis at minimum), which acted as deflationary sources for landward foredune development. Only a limited number of such late-Holocene beach ridges survive in the observed prograded series. Beach ridges only survive when capped by storm-generated gravel beaches that are deposited on a mesoscale time spacing of 50–130 years. The morphodynamic shift from a dissipative beach face for dune formation to a reflective beach face for gravel capping appears to be controlled by the beach sand volume falling to a level where reflective conditions can prevail. Sediment volume entering the beach is thought to have fluctuated as a function of a forced regression associated with the falling sea level from the mid-Holocene highstand (ca. 6000 cal. yr BP) identified in north-east Ireland. The prograded beach ridges dated at ca. 3000 to 2000 cal. yr BP indicate that the Holocene highstand’s regressive phase may have lasted longer than previously specified.

Organisational controls, typologies and time scales of paraglacial gravel-dominated coastal systems

The fundamental controls on the initiation and development of gravel-dominated deposits (beaches and barriers) on paraglacial coasts are particle size and shape, sediment supply, storm wave activity (primarily runup), relative sea-level (RSL) change, and terrestrial basement structure (primarily as it affects accommodation space). This paper examines the stochastic basis for barrier organisation as shown by variation in gravel barrier architecture. We recognise punctuated self-organisation of barrier development that is disrupted by short phases of barrier instability. The latter results from positive feedback causing barrier breakdown when sediment supply is exhausted. We examine published typologies for gravel barriers and advocate a consolidated perspective using rate of RSL change and sediment supply. We also consider the temporal variation in controls on barrier development. These are examined in terms of a simple behavioural model (BARCH) for prograding gravel barrier architecture and its sensitivity to such controls. The nature of macroscale (102–103 years) gravel barrier development, including inherited characteristics that influence barrier genesis, as well as forcing from changing RSL, sediment supply, headland control and barrier inertia, is examined in the context of long-surviving barriers along the southern England coastline.

Challenging assumptions of future coastal habitat development around the UK

One habitat management requirement forced by 21st century relative sea-level rise (RSLR), will be the need to re-comprehend the dimensions of long-term transgressive behaviour of coastal systems being forced by such RSLR. Fresh approaches to the conceptual modelling and subsequent implementation of new coastal and peri-marine habitats will be required. There is concern that existing approaches to forecasting coastal systems development (and by implication their associated scarce coastal habitats) over the next century depend on a certain premise of orderly spatial succession of habitats. This assumption is shown to be questionable given the possible future rates of RSLR, magnitude of shoreline retreat and the lack of coastal sediment to maintain the protective morphologies to low-energy coastal habitats. Of these issues, sediment deficiency is regarded as one of the major problem for future habitat development. Examples of contemporary behaviour of UK coasts show evidence of coastal sediment starvation resulting from relatively stable RSLR, anthropogenic sealing of coastal sources, and intercepted coastal sediment pathways, which together force segmentation of coastal systems. From these examples key principles are deduced which may prejudice the existence of future habitats: accelerated future sediment demand due to RSLR may not be met by supply and, if short- to medium-term hold-the-line policies predominate, long-term strategies for managed realignment and habitat enhancement may prove impossible goals. Methods of contemporary sediment husbandry may help sustain some habitats in place but otherwise, instead of integrated coastal organization, managers may need to consider coastal breakdown, segmentation and habitat reduction as the basis of 21st century coastal evolution and planning.

Description and search labor for information retrieval

Selection power is taken as the fundamental value for information retrieval systems. Selection power is regarded as produced by selection labor, which itself separates historically into description and search labor. As forms of mental labor, description and search labor participate in the conditions for labor and for mental labor. Concepts and distinctions applicable to physical and mental labor are indicated, introducing the necessity of labor for survival, the idea of technology as a human construction, and the possibility of the transfer of human labor to technology. Distinctions specific to mental labor, particular between semantic and syntactic labor, are introduced. Description labor is exemplified by cataloging, classification, and database description, can be more formally understood as the labor involved in the transformation of objects for description into searchable descriptions, and is also understood to include interpretation. The costs of description labor are discussed. Search labor is conceived as the labor expended in searching systems. For both description and search labor, there has been a progressive reduction in direct human labor, with its syntactic aspects transferred to technology, effectively compelled by the high relative costs of direct human labor compared to machine processes.

A labor theoretic approach to information retrieval

This article synthesizes the labor theoretic approach to information retrieval. Selection power is taken as the fundamental value for information retrieval and is regarded as produced by selection labor. Selection power remains relatively constant while selection labor modulates across oral, written, and computational modes. A dynamic, stemming principally from the costs of direct human mental labor and effectively compelling the transfer of aspects of human labor to computational technology, is identified. The decision practices of major information system producers are shown to conform with the motivating forces identified in the dynamic. An enhancement of human capacities, from the increased scope of description processes, is revealed. Decision variation and decision considerations are identified. The value of the labor theoretic approach is considered in relation to pre-existing theories, real world practice, and future possibilities. Finally, the continuing intractability of information retrieval is suggested.