Don't Spread Yourself Too Thin: The Impact of Task Juggling on Workers' Speed of Job Completion

We show that task juggling, i.e., the spreading of effort across too many active projects, decreases the performance of workers, raising the chances of low throughput, long duration of projects and exploding backlogs. Individual speed of job completion cannot be explained only in terms of effort, ability and experience: work scheduling is a crucial "input" that cannot be omitted from the production function of individual workers. We provide a simple theoretical model to study the effects of increased task juggling on the duration of projects. Using a sample of Italian judges we show that those who are induced for exogenous reasons to work in a more parallel fashion on many trials at the same time, take longer to complete similar portfolios of cases. The exogenous variation that identifies this causal effect is constructed exploiting the lottery that assigns cases to judges together with the procedural prescription requiring judges to hold the first hearing of a case no later than 60 days from filing.individual production function, work scheduling, duration of trials

Designing networked learning with 4Ts

This paper tackles the issue of how to support the design of effective collaborative activities in networked learning contexts. At the crossover between the ‘learning design' and the ‘networked learning' research sectors, notions such as ‘collaborative techniques', ‘design patterns' or ‘scripts' are often used to describe and/or run online collaborative learning activities. Based on these concepts, technological tools have been implemented that reify these notions and support several phases of the learning design process, including the sharing and reuse of design representations. Despite the differences among tools, most of the them support the representation of learning designs that are already "in the designer's mind", while few technological tools specifically provide guidance and support in the early phase of the design process of collaborative activities, i.e. the conceptualization of the design. Focusing on this gap, this paper proposes a model and, based on it, a game supporting the conceptualization of online collaborative activities for networked learning contexts. Both the model and the game are based on the interplay of four variables, the 4Ts: Task, Teams, Time and Technology, regarded as the key aspects of the decisions to be made. The model suggests that, to design the online activity, the teacher/designer will need to "juggle" around with these four variables and their reciprocal relationships in a cyclic, iterative process, regardless of whether she wants to start the design from scratch or to reuse an already existing collaborative. Implemented with the aim of scaffolding such iterative process and supporting a group of teachers in the decision taking phases, the game consists of a board, representing the Time component, and of 5 decks of cards (respectively for the Task, Team, Technology, Technique and the Jokers). Each deck contains cards describing instances of Task, Team, Technology or Technique, while the Joker cards are empty and should be filled in by players with new instances. To guide the decisions, each card illustrates the dependencies between that particular instance of T and the others, thus making the decision criteria as explicit as possible and stimulating reflection on how each variable impacts on the others. Both the 4Ts model and the game have been field tested and evaluated by the developers with a group of 48 teachers. The results encourage the development of a digital version of the game, where cards are still tangible objects, and augmented reality techniques are employed to digitize the results of conceptualisation

Don’t Spread Yourself Too Thin: The Impact of Task Juggling on Workers’ Speed of Job Completion

We show that task juggling, i.e., the spreading of effort across too many active projects, decreases the performance of workers, raising the chances of low throughput, long duration of projects and exploding backlogs. Individual speed of job completion cannot be explained only in terms of effort, ability and experience: work scheduling is a crucial “input” that cannot be omitted from the production function of individual workers. We provide a simple theoretical model to study the effects of increased task juggling on the duration of projects. Using a sample of Italian judges we show that those who are induced for exogenous reasons to work in a more parallel fashion on many trials at the same time, take longer to complete similar portfolios of cases. The exogenous variation that identifies this causal effect is constructed exploiting the lottery that assigns cases to judges together with the procedural prescription requiring judges to hold the first hearing of a case no later than 60 days from filing.

Effects of business uncertainty on turnover

Wedocumentacausalrelationshipbetweenbusinessuncertaintyandworkforcemanagementatthefirmlevel,byleveraginglitigation-generatedquasi-experimentalvariationinbusinessuncertainty.Thecausaleffectsofbusinessuncertaintyonturnover, hiringandseparationsareof theexpectednegativedirection, andof sizablemagnitude. These consequences are stronger amongfirms that operate insectors in whichbusinessuncertaintyisintrinsicallyhigher,andcanbeattributedtotheeffect of regulationinducedbusiness riskonnormal operations. Inparticular, employee turnover,hiringandseparationsareratcheteddowntoreducetheriskofadditional wrongful terminationlawsuits. Valueaddedisalsoshowntodecrease inbusiness risk

A parallel view for search engines

To engineer a search engine is a challenging task. Search engines index tens to hundreds of millions of web pages involving a comparable number of distinct terms. They answer tens of n-tillions of queries every day. Despite the importance of large-scale search engines on the Web, very little academic research has been done on them. Furthermore, due to rapid advance in technology and web proliferation, creating a web search engine today is very different from years ago. In most papers the index simply ”is”, without discussion of how it was created. But for a indexing scheme to be useful it must be possible for the index to be constructed in a reasonable amount of time, and so papers describing complex indexing methods should also describe and analyze a mechanism whereby the index can be built. Scalability is of concern during index construction as well as during query processing. This paper describes the cooperative work between the Crawler, Indexer and the Searcher.VI Workshop de Procesamiento Distribuido y Paralelo (WPDP)Red de Universidades con Carreras en Informática (RedUNCI

The Impact of Antiviral Therapy and the Influence of Metabolic Cofactors on the Outcome of Chronic HCV Infection

Natural history of HCV related chronic hepatitis is influenced and modified by many factors: virus features, coinfections and host characteristics. In particular, a peculiar genetic background of the host by conditioning the occurrence of intracellular metabolic derangements (i.e., insulin resistance) might contribute to accelerate the rate of progression to cirrhosis and eventually the occurrence of hepatocellular carcinoma (HCC) and death. Likely, direct interplays between virus genotype and host genetic background might be hypothesized at this level. Morbidity and mortality in cirrhosis is primarily associated with complications of liver cirrhosis (ascites, hepatic encephalopathy, jaundice, and gastroesophageal bleeding) and HCC occurrence. Therefore the main goal of therapy is to clear viral infection and decrease liver necro-inflammation that directly relates to development of cirrhosis and HCC. Among patients treated with Interferon-based therapy, those with sustained viral response showed a significant reduction of progression to cirrhosis and development of HCC. However, a residual risk of hepatocellular carcinoma still remains indicating the need for careful follow-up using ultrasonography every six months in cirrhotic patients, even in those showing persistently normal ALT and undetectable HCV RNA levels after antiviral therapy

Cross-comparative analysis of loads and power of pitching floating offshore wind turbine rotors using frequency-domain Navier-Stokes CFD and blade element momentum theory

Reliable predictions of the aero- and hydrodynamic loads acting on floating offshore wind turbines are paramount for assessing fatigue life, designing load and power control systems, and ensuring the overall system stability at all operating conditions. However, significant uncertainty affecting both predictions still exists. This study presents a cross-comparative analysis of the predictions of the aerodynamic loads and power of floating wind turbine rotors using a validated frequency-domain Navier-Stokes Computational Fluid Dynamics solver, and a state-of-the-art Blade Element Momentum theory code. The considered test case is the National Renewable Energy Laboratory 5 MW turbine, assumed to be mounted on a semi-submersible platform. The rotor load and power response at different pitching regimes is assessed and compared using both the high- and low-fidelity methods. The overall qualitative agreement of the two prediction sets is found to be excellent in all cases. At a quantitative level, the high- and low-fidelity predictions of both the mean rotor thrust and the blade out-of-plane bending moments differ by about 1 percent, whereas those of the mean rotor power differ by about 6 percent. Part of these differences at high pitching amplitude appear to depend on differences in dynamic stall predictions of the approaches

Assessing the sensitivity of stall-regulated wind turbine power to blade design using high-fidelity computational fluid dynamics

This study provides a novel contribution toward the establishment of a new high-fidelity simulation-based design methodology for stall-regulated horizontal axis wind turbines. The aerodynamic design of these machines is complex, due to the difficulty of reliably predicting stall onset and poststall characteristics. Low-fidelity design methods, widely used in industry, are computationally efficient, but are often affected by significant uncertainty. Conversely, Navier–Stokes computational fluid dynamics (CFD) can reduce such uncertainty, resulting in lower development costs by reducing the need of field testing of designs not fit for purpose. Here, the compressible CFD research code COSA is used to assess the performance of two alternative designs of a 13-m stall-regulated rotor over a wide range of operating conditions. Validation of the numerical methodology is based on thorough comparisons of novel simulations and measured data of the National Renewable Energy Laboratory (NREL) phase VI turbine rotor, and one of the two industrial rotor designs. An excellent agreement is found in all cases. All simulations of the two industrial rotors are time-dependent, to capture the unsteadiness associated with stall which occurs at most wind speeds. The two designs are cross-compared, with emphasis on the different stall patterns resulting from particular design choices. The key novelty of this work is the CFD-based assessment of the correlation among turbine power, blade aerodynamics, and blade design variables (airfoil geometry, blade planform, and twist) over most operational wind speeds

Un acercamiento a los servicios y aplicaciones Web para los terminales móviles

El auge de las redes móviles [1, 2] ha provocado la aparición de grupos de investigación para afrontar los diversos servicios que se pueden implementar en Internet. En este trabajo se intenta estudiar un servicio Web de valor añadido en un terminal móvil, Servicio de Tiempo de Espera de Bus. Para ello, se presenta la tecnología WAP [3] y XHTML, para abordar la problemática de las redes móviles ante el reto de especificar, diseñar e implementar aplicaciones y servicios en este entorno [4]. Por último, se finaliza este trabajo de investigación anticipando futuros trabajos y conclusiones en este campo.VI Workshop de Procesamiento Distribuido y Paralelo (WPDP)Red de Universidades con Carreras en Informática (RedUNCI