Artifact usefulness and usage in sensemaking handoffs

The complexities of sensemaking suggest that collaboration should be difficult, requiring a rich ecology of collaboration support. This can be a problem for handoff sensemaking, where one person must continue where another has left off, sometimes with only material artifacts as the basis of the handoff. A detailed analysis of essential attributes of sensemaking tasks, and elements identified in the computer supported collaborative work literature were combined to yield insight into handoff sensemaking and guide empirical work. A lab-study showed that handoffs relying only on artifacts from previous sensemaking could be successful. The lab studies also indicated timing and quality affects on the sensemaking handoffs, with different quality materials used differently, and early efforts possibly being particularly difficult to hand off. Design of support for sensemaking handoffs will have to take such effects into account.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/78323/1/1450460219_ftp.pd

Using Category Information for Relationship Exploration in Textual Data

In the comprehension of textual data, it is critical for people to perceive relationships between topics. This work explores two approaches that use text categorizations to reveal underlying relationships: the Overlap approach, which visualizes overlaps between categories, and the Search approach, which shows topical search results in the context of categories. The effectiveness of these approaches is tested using various types of relationship questions. Our results show that the Overlap approach improves users' performances in relationship exploration tasks. Conversely, the Search approach did not show the same effectiveness, primarily due to the Vocabulary Problem. Design implications are drawn from the experiment.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/57318/1/14504301163_ftp.pd

Biogeochemical and ecological impacts of boundary currents in the Indian Ocean

Monsoon forcing and the unique geomorphology of the Indian Ocean basin result in complex boundary currents, which are unique in many respects. In the northern Indian Ocean, several boundary current systems reverse seasonally. For example, upwelling coincident with northward-flowing currents along the coast of Oman during the Southwest Monsoon gives rise to high productivity which also alters nutrient stoichiometry and therefore, the species composition of the resulting phytoplankton blooms. During the Northeast Monsoon most of the northern Indian Ocean boundary currents reverse and favor downwelling. Higher trophic level species have evolved behavioral responses to these seasonally changing conditions. Examples from the western Arabian Sea include vertical feeding migrations of a copepod (Calanoides carinatus) and the reproductive cycle of a large pelagic fish (Scomberomorus commerson). The impacts of these seasonal current reversals and changes in upwelling and downwelling circulations are also manifested in West Indian coastal waters, where they influence dissolved oxygen concentrations and have been implicated in massive fish kills. The winds and boundary currents reverse seasonally in the Bay of Bengal, though the associated changes in upwelling and productivity are less pronounced. Nonetheless, their effects are observed on the East Indian shelf as, for example, seasonal changes in copepod abundance and zooplankton community structure. In contrast, south of Sri Lanka seasonal reversals in the boundary currents are associated with dramatic changes in the intensity of coastal upwelling, chlorophyll concentration, and catch per unit effort of fishes. Off the coast of Java, monsoon-driven changes in the currents and upwelling strongly impact chlorophyll concentrations, seasonal vertical migrations of zooplankton, and sardine catch in Bali Strait. In the southern hemisphere the Leeuwin is a downwelling-favorable current that flows southward along western Australia, though local wind forcing can lead to transient near shore current reversals and localized coastal upwelling. The poleward direction of this eastern boundary current is unique. Due to its high kinetic energy the Leeuwin Current sheds anomalous, relatively high chlorophyll, warm-core, downwelling eddies that transport coastal diatom communities westward into open ocean waters. Variations in the Leeuwin transport and eddy generation impact many higher trophic level species including the recruitment and fate of rock lobster (Panulirus cygnus) larvae. In contrast, the transport of the Agulhas Current is very large, with sources derived from the Mozambique Channel, the East Madagascar Current and the southwest Indian Ocean sub-gyre. Dynamically, the Agulhas Current is upwelling favorable; however, the spatial distribution of prominent surface manifestations of upwelling is controlled by local wind and topographic forcing. Meanders and eddies in the Agulhas Current propagate alongshore and interact with seasonal changes in the winds and topographic features. These give rise to seasonally variable localized upwelling and downwelling circulations with commensurate changes in primary production and higher trophic level responses. Due to the strong influence of the Agulhas Current, many neritic fish species in southeast Africa coastal waters have evolved highly selective behaviors and reproductive patterns for successful retention of planktonic eggs and larvae. For example, part of the Southern African sardine (Sardinops sagax) stock undergoes a remarkable northward migration enhanced by transient cyclonic eddies in the shoreward boundary of the Agulhas Current. There is evidence from the paleoceanographic record that these currents and their biogeochemical and ecological impacts have changed significantly over glacial to interglacial timescales. These changes are explored as a means of providing insight into the potential impacts of climate change in the Indian Ocean

Building a Pixel Rewriting System Using Only Pixel Rewrites

Additional support materials include (1) Approximate Lisp language translations of the graphical system implemented. (2) Some interesting trivia about the system. (3) Pointers to related material.This is a followup to Anderson&Furnas2010, where we compare two graphical diagrammatic reasoning systems.This video shows a 2Dimensional pixel rewriting system implementing itself. It develops a high-level programming language run completely by pixel-level graphical rewrites, and that language is used to program a scaled down version of itself.http://deepblue.lib.umich.edu/bitstream/2027.42/83491/1/Furnas-Bitpict_Implements_Itself-Part1.movhttp://deepblue.lib.umich.edu/bitstream/2027.42/83491/2/Furnas-Bitpict_Implements_Itself-Part2.movhttp://deepblue.lib.umich.edu/bitstream/2027.42/83491/3/Furnas-Bitpict_Implements_Itself-Part3.movhttp://deepblue.lib.umich.edu/bitstream/2027.42/83491/4/Bitpict_Implements_Itself-Trivia.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/83491/5/Bitpict_Implements_Itself-LispGloss.pd

Metric family portraits

Metric space, Distance matrices, High-dimensional graphics,