ArguCast: a system for online multi-forecasting with gradual argumentation

Judgmental forecasting is a form of forecasting which employs (human) users to make predictions about specied future events. Judgmental forecasting has been shown to perform better than quantitative methods for forecasting, e.g. when historical data is unavailable or causal reasoning is needed. However, it has a number of limitations, arising from users’ irrationality and cognitive biases. To mitigate against these phenomena, we leverage on computational argumentation, a eld which excels in the representation and resolution of conicting knowledge and human-like reasoning, and propose novel ArguCast frameworks (ACFs) and the novel online system ArguCast, integrating ACFs. ACFs and ArguCast accommodate multi-forecasting, by allowing multiple users to debate on multiple forecasting predictions simultaneously, each potentially admitting multiple outcomes. Finally, we propose a novel notion of user rationality in ACFs based on votes on arguments in ACFs, allowing the ltering out of irrational opinions before obtaining group forecasting predictions by means commonly used in judgmental forecasting

The Gravitational and Electrostatic Fields Far from an Isolated Einstein-Maxwell Source

The exterior solution for an arbitrary charged, massive source, is studied as a static deviation from the Reissner-Nordstr\o m metric. This is reduced to two coupled ordinary differential equations for the gravitational and electrostatic potential functions. The homogeneous equations are explicitly solved in the particular case $q^2=m^2$, obtaining a multipole expansion with radial hypergeometric dependence for both potentials. In the limiting case of a neutral source, the equations are shown to coincide with recent results by Bondi and Rindler.Comment: 11 pages, revTe

Preliminary Results of Commercial Sea Scallop Survey in the Hudson Canyon South Closed Area June 2000

This report presents the preliminary results of the commercial survey of the Hudson Canyon Closed Area. The survey was conducted aboard the FN Alice Amanda from June 8-15, 2000. A systematic grid design was utilized with survey stations located approximately 5 nm apart (Figure 1). Survey stations were located both inside and outside the boundaries of the closed area. Additional stations were added along the western, northern and southern boundaries in an attempt to resolve the boundary effects on sea scallop abundance and size distribution. Survey tows were 10 minutes in duration at a speed of 4.5-5.0 kts. The sampling gear consisted of two standard 15 ft. New Bedford style sea scallop dredges with 8 inch twine tops, ring bags knit with 3.5 ·(88.9 mm) rings, and no tickler or rock chains. An inclinometer was attached to the frame of the starboard dredge to measure dredge angle and bottom contact time. The results of the initial data analysis are shown in Figures 2-8. Catch data are shown in Figures 2-4 with scallop catches separated into two categories of shell height: less than 90 mm (Figure 2) and greater than or equal to 90 mm shell height (Figure 3). A total scallop catch at each station is shown in Figure 4. Differences in sea scallop abundance and size structure were examined with respect to samples taken inside or outside of the closed area (Figure 5), strata calculated by dividing the closed area into equal North and South portions along the 39° 01.566\u27 latitude (Figure 6), and by depth regimes within the closed area (Figure 7). Catch data stratified by two factors: 1). North and South 2). inside and outside the closed area are shown in Table 1. The initial biomass estimate is shown in Table 2. The following assumptions were used in calculating biomass: 1. Stratification of the closed area into two roughly equal portions. 2. Utilizing a systematic grid design, number of stations was proportional to area of strata. 3. Tows that fell on closed area boundary were included in the calculation. 4. All scallops harvested were included 5. The coefficients of the shell height-meat weight relationship a=-12.1628 b=3.2539. 6. A nominal tow length of 1 nm. Each tow covered 0.00494 nm2 7. A dredge efficiency of 40% 8. Harvest represents a removal of 25% of the standing stock The next iterations of biomass estimates will follow accordingly: 1. The number of scallops from 80-100 mm will be corrected for the selectivity of the 3.5 ring dredge. This means that the total number of scallops at each 5 mm interval from 80-100 mm will increase. Consequently, their contribution will also increase the biomass estimate. We will still use the nominal tow length of l nm and a 40% dredge efficiency. 2. The biomass estimate in l will be calculated to account for growth and natural mortality (0.1) to project the standing stock in 2001. 3. The biomass estimate in l and 2 will be calculated to account for actual tow length and changes in dredge efficiency based on the 1999 depletion experiments in the Hudson Canyon Closed Area on 100+ mm scallop

Results of Commercial Sea Scallop Survey in the Virginia Beach Closed Area September 2000

This report presents the results of the commercial survey of the Virginia Beach Closed Area. The survey was conducted aboard the commercial sea scallop vessel F IV Alice Amanda from Hampton VA. Sampling began September 19, 2000 and was completed September 22, 2000

Results of Commercial Sea Scallop Survey in the Hudson Canyon South Closed Area

This report presents the results of the commercial survey of the Hudson Canyon Closed Area. The survey was conducted aboard the FN Alice Amanda from June 8-15, 2000. A systematic grid design was utilized with survey stations located approximately 5 nm apart (Figure l ). Survey stations were located both inside and outside the boundaries of the closed area. Additional stations were added along the western, northern ru1d southern boundaries in an attempt to resolve the boundary effects on sea scallop abundance and size distribution. Survey tows were l O minutes in duration at a speed of 4.5-5.0 kts. The sampling gear consisted of two standard 15 ft. New Bedford style sea scallop dredges with 8 inch twine tops. ring bags knit with 3.5\u27\u27 (88.9 mm) rings, and no tickler or rock chains. An inclinometer was attached to the frame of the starboard dredge to measure dredge angle and bottom contact time. The results of the initial data analysis are shovm in Figures 2-8. Catch data are shown in Figures 2-4 with scallop catches separated into two categories of shell height: less than 90 mm (Figure 2) and greater than or equal to 90 mm shell height (Figure 3). A total scallop catch at each station is shown in Figure 4. Differences in sea scallop abundance and size structure were examined with respect to samples taken inside or outside of the closed area (Figure 5), strata calculated by dividing the closed area into equal North and South portions along the 39° 01.566\u27 latitude (Figure 6), and by depth regimes within the closed area (Figure 7). Catch data stratified by two factors: 1 ). North and South 2). inside and outside the closed area are shown in Table l. The initial biomass estimate is shown in Table 2. The following assumptions were used in calculating biomass: l. Stratification of the closed area into two roughly equal portions. 2. Utilizing a systematic grid design, number of stations was proportional to area of strata. 3. Tows that fell on closed area boundary were included in the calculation. 4. All scallops harvested were included 5. The coefficients of the shell height-meat weight relationship a=-12.1628 b=3.2539. 6. A nominal tow length of 1 nm. Each tow covered 0.00494 nm2 • 7. A dredge efficiency of 40% 8. Harvest represents a removal of 25% of the standing stoc

Ergodic sampling of the topological charge using the density of states

In lattice calculations, the approach to the continuum limit is hindered by the severe freezing of the topological charge, which prevents ergodic sampling in configuration space. In order to significantly reduce the autocorrelation time of the topological charge, we develop a density of states approach with a smooth constraint and use it to study SU(3) pure Yang Mills gauge theory near the continuum limit. Our algorithm relies on simulated tempering across a range of couplings, which guarantees the decorrelation of the topological charge and ergodic sampling of topological sectors. Particular emphasis is placed on testing the accuracy, efficiency and scaling properties of the method. In their most conservative interpretation, our results provide firm evidence of a sizeable reduction of the exponent z related to the growth of the autocorrelation time as a function of the inverse lattice spacing

Measurement errors in body size of sea scallops (Placopecten magellanicus) and their effect on stock assessment models

Body-size measurement errors are usually ignored in stock assessments, but may be important when body-size data (e.g., from visual sur veys) are imprecise. We used experiments and models to quantify measurement errors and their effects on assessment models for sea scallops (Placopecten magellanicus). Errors in size data obscured modes from strong year classes and increased frequency and size of the largest and smallest sizes, potentially biasing growth, mortality, and biomass estimates. Modeling techniques for errors in age data proved useful for errors in size data. In terms of a goodness of model fit to the assessment data, it was more important to accommodate variance than bias. Models that accommodated size errors fitted size data substantially better. We recommend experimental quantification of errors along with a modeling approach that accommodates measurement errors because a direct algebraic approach was not robust and because error parameters were diff icult to estimate in our assessment model. The importance of measurement errors depends on many factors and should be evaluated on a case by case basis

Curvature singularity of the distributional BTZ black hole geometry

For the non-rotating BTZ black hole, the distributional curvature tensor field is found. It is shown to have singular parts proportional to a $\delta$-distribution with support at the origin. This singularity is related, through Einstein field equations, to a point source. Coordinate invariance and independence on the choice of differentiable structure of the results are addressed.Comment: Latex, 7 page

Compact anisotropic spheres with prescribed energy density

New exact interior solutions to the Einstein field equations for anisotropic spheres are found. We utilise a procedure that necessitates a choice for the energy density and the radial pressure. This class contains the constant density model of Maharaj and Maartens (Gen. Rel. Grav., Vol 21, 899-905, 1989) and the variable density model of Gokhroo and Mehra (Gen. Rel. Grav., Vol 26, 75-84, 1994) as special cases. These anisotropic spheres match smoothly to the Schwarzschild exterior and gravitational potentials are well behaved in the interior. A graphical analysis of the matter variables is performed which points to a physically reasonable matter distribution.Comment: 22 pages, 3 figures, to appear in Gen. Rel. Gra