scholarly journals Known Unknowns: Sir John Davies’ Nosce Teipsum in Conversation

2021 ◽  
Vol 51 (3) ◽  
pp. 383-408
Author(s):  
Anthony Ossa-Richardson
Keyword(s):  
Known Unknowns

Macrolides: known knowns, and known unknowns

Pneumologie ◽  
2016 ◽  
Vol 70 (10) ◽  
Author(s):  
C Wong
Keyword(s):  
Known Unknowns

scholarly journals Planning of technical flood retention measures in large river basins under consideration of imprecise probabilities of multivariate hydrological loads

2009 ◽  
Vol 9 (4) ◽  
pp. 1349-1363 ◽  
Author(s):  
D. Nijssen ◽  
A. Schumann ◽  
M. Pahlow ◽  
B. Klein
Keyword(s):  
Flood Control ◽  
Large River ◽  
Control Measures ◽  
Imprecise Probabilities ◽  
Flood Events ◽  
Modeling Tools ◽  
Statistical Characterization ◽  
Design Floods ◽  
Known Unknowns ◽  
Flood Waves

Abstract. As a result of the severe floods in Europe at the turn of the millennium, the ongoing shift from safety oriented flood control towards flood risk management was accelerated. With regard to technical flood control measures it became evident that the effectiveness of flood control measures depends on many different factors, which cannot be considered with single events used as design floods for planning. The multivariate characteristics of the hydrological loads have to be considered to evaluate complex flood control measures. The effectiveness of spatially distributed flood control systems differs for varying flood events. Event-based characteristics such as the spatial distribution of precipitation, the shape and volume of the resulting flood waves or the interactions of flood waves with the technical elements, e.g. reservoirs and flood polders, result in varying efficiency of these systems. Considering these aspects a flood control system should be evaluated with a broad range of hydrological loads to get a realistic assessment of its performance under different conditions. The consideration of this variety in flood control planning design was one particular aim of this study. Hydrological loads were described by multiple criteria. A statistical characterization of these criteria is difficult, since the data base is often not sufficient to analyze the variety of possible events. Hydrological simulations were used to solve this problem. Here a deterministic-stochastic flood generator was developed and applied to produce a large quantity of flood events which can be used as scenarios of possible hydrological loads. However, these simulations imply many uncertainties. The results will be biased by the basic assumptions of the modeling tools. In flood control planning probabilities are applied to characterize uncertainties. The probabilities of the simulated flood scenarios differ from probabilities which would be derived from long time series. With regard to these known unknowns the bias of the simulations was considered by imprecise probabilities. Probabilities, derived from measured flood data were combined with probabilities which were estimated from long simulated series. To consider imprecise probabilities, fuzzy sets were used to distinguish the results between more or less possible design floods. The need for such a differentiated view on the performance of flood protection systems is demonstrated by a case study.

Urbanisation and Political Change in Pakistan: exploring the known unknowns

2013 ◽  
Vol 34 (7) ◽  
pp. 1293-1304 ◽  
Author(s):  
Daanish Mustafa ◽  
Amiera Sawas
Keyword(s):  
Political Change ◽  
Known Unknowns

Nanotechnology: The Challenge of Regulating Known Unknowns

2006 ◽  
Vol 34 (4) ◽  
pp. 704-713 ◽  
Author(s):  
Robin Fretwell Wilson
Keyword(s):  
Occupational Health ◽  
Pulmonary Edema ◽  
Nanosized Particles ◽  
Washington Post ◽  
Respiratory Problems ◽  
Known Unknowns

Nanotechnology is a subject about which we know less than we should, but probably more than we think we do at first glance. Like Defense Secretary Donald Rumsfeld's “known unknowns,” we have learned enough to know what we should be concerned with. Glimmers of risk cropped up recently when German authorities recalled a bathroom cleansing product, “MagicNano,” that purported to contain nanosized particles (NSPs) and was on the market for only three days. More than one hundred people suffered severe respiratory problems – six of whom were hospitalized with pulmonary edema. Although a subsequent analysis of MagicNano found that the nanoliquid ingredient morphed in the production into “supersized” (not nanosized) particles, the recall nonetheless turned a white hot spotlight on the risk of NSPs. Latching onto the risks posed to workers producing materials using nanotechnology, the Washington Post has labeled nanotechnology a “seat-of-thepants occupational health experiment.”

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