Visual interaction: models, systems, prototypes. The Pictorial Computing Laboratory at the University of Rome “La Sapienza”

This paper reports on the research activities performed by the Pictorial Computing Laboratory at the University of Rome, La Sapienza, during the last 5 years. Such work, essentially is based on the study of humancomputer interaction, spans from metamodels of interaction down to prototypes of interactive systems for both synchronous multimedia communication and groupwork, annotation systems for web pages, also encompassing theoretical and practical issues of visual languages and environments also including pattern recognition algorithms. Some applications are also considered like e-learning and collaborative work.     

Mapping the perceptual structure of rectangles through goodness-of-fit ratings

Three experiments were carried out to investigate the internal structure of a rectangular frame to test Arnheim's (1974 Art and Visual Perception, 1988 The Power of the Center) proposals about its 'structural skeleton'. Observers made subjective ratings of how well a small probe circle fit within a rectangle at different interior positions. In experiment 1, ratings of 77 locations were highest in the center, decreased with distance from the center, greatly elevated along vertical and horizontal symmetry axes, and somewhat elevated along the local symmetry axes. A linear regression model with six symmetry-related factors accounted for 95% of the variance. In experiment 2 we measured perceived fit along local symmetry axes versus global diagonals near the corners to determine which factor was relevant. 2AFC probabilities were elevated only along the local symmetry axes and were higher when the probe was closer to the vertex. In experiment 3 we examined the effect of dividing a rectangular frame into two rectangular 'subframes' using an additional line. The results show that the primary determinant of good fit is the position of the target circle within the local subframes. In general, the results are consistent with Arnheim's proposals about the internal structure of a rectangular frame, but an alternative interpretation is offered in terms of the Gestalt concept of figural goodness.     

Plant neurobiology: from sensory biology,via plant communication,to social plant behavior

In plants, numerous parameters of both biotic and abiotic environments are continuously monitored. Specialized cells are evolutionary-optimized for effective translation of sensory input into developmental and motoric output. Importantly, diverse physical forces, influences, and insults induce immediate electric responses in plants. Recent advances in plant cell biology, molecular biology, and sensory ecology will be discussed in the framework of recently initiated new discipline of plant sciences, namely plant neurobiology.     

Does Arguing from Coherence Make Sense?

In this paper the argument from coherence is submitted to a critical analysis. First, it is argued to be a complex form of coordinative argumentation, structured on various argumentative levels. Then, using the pragma-dialectical theory of argumentation a distinction is brought out between two basic forms of the argument from coherence: in one use this argument occurs as a sequence of two symptomatic arguments; in the other use we have a main symptomatic argument supported by a subordinate pragmatic argument. Finally, from an evaluative point of view it is assessed whether the argument from coherence can be found acceptable as a tool for settling disputes. It is claimed that in general, we can welcome this argumentative structure as sound and fully acceptable provided that we are aware of the interpretative discretion its use implies. A preliminary version of this essay was presented at the symposium organised by the Department of Speech Communication, Argumentation Theory, and Rhetoric at the University of Amsterdamon the 27/02/04. I wish to express my indebtedness to Dora Achourioti, Francesco Belvisi, Frans van Eemeren, Eveline Feteris, Bart Garssen, Jean Wagemans, Peter Houtlosser, and Henrike Jansen for their helpful remarks. Needless to say, the responsibility for the views expressed herein as well as for any errors of form or content rests solely with me.