scholarly journals Topics of Controversy: An Empirical Analysis of Web Censorship Lists

2017 ◽  
Vol 2017 (1) ◽  
pp. 42-61 ◽  
Author(s):  
Zachary Weinberg ◽  
Mahmood Sharif ◽  
Janos Szurdi ◽  
Nicolas Christin
Keyword(s):  
Experimental Design ◽  
Empirical Analysis ◽  
Experimental Technique ◽  
A Priori ◽  
Access Network ◽  
Network Resources ◽  
Internet Censorship

AbstractStudies of Internet censorship rely on an experimental technique called probing. From a client within each country under investigation, the experimenter attempts to access network resources that are suspected to be censored, and records what happens. The set of resources to be probed is a crucial, but often neglected, element of the experimental design.We analyze the content and longevity of 758,191 webpages drawn from 22 different probe lists, of which 15 are alleged to be actual blacklists of censored webpages in particular countries, three were compiled using a priori criteria for selecting pages with an elevated chance of being censored, and four are controls. We find that the lists have very little overlap in terms of specific pages. Mechanically assigning a topic to each page, however, reveals common themes, and suggests that handcurated probe lists may be neglecting certain frequently censored topics. We also find that pages on controversial topics tend to have much shorter lifetimes than pages on uncontroversial topics. Hence, probe lists need to be continuously updated to be useful.To carry out this analysis, we have developed automated infrastructure for collecting snapshots of webpages, weeding out irrelevant material (e.g. site “boilerplate” and parked domains), translating text, assigning topics, and detecting topic changes. The system scales to hundreds of thousands of pages collected.

On Adaptive Sampling for Single and Multi-Response Bayesian Surrogate Models

2006 ◽  
Author(s):  
David A. Romero ◽  
Cristina H. Amon ◽  
Susan Finger
Keyword(s):  
Experimental Design ◽  
Adaptive Sampling ◽  
Design Space Exploration ◽  
A Priori ◽  
Computer Experiments ◽  
Latin Hypercube Sampling ◽  
Surrogate Models ◽  
Sampling Techniques ◽  
Design And Optimization ◽  
Sampling Points

In order to reduce the time and resources devoted to design-space exploration during simulation-based design and optimization, the use of surrogate models, or metamodels, has been proposed in the literature. Key to the success of metamodeling efforts are the experimental design techniques used to generate the combinations of input variables at which the computer experiments are conducted. Several adaptive sampling techniques have been proposed to tailor the experimental designs to the specific application at hand, using the already-acquired data to guide further exploration of the input space, instead of using a fixed sampling scheme defined a priori. Though mixed results have been reported, it has been argued that adaptive sampling techniques can be more efficient, yielding better surrogate models with less sampling points. In this paper, we address the problem of adaptive sampling for single and multi-response metamodels, with a focus on Multi-stage Multi-response Bayesian Surrogate Models (MMBSM). We compare distance-optimal latin hypercube sampling, an entropy-based criterion and the maximum cross-validation variance criterion, originally proposed for one-dimensional output spaces and implemented in this paper for multi-dimensional output spaces. Our results indicate that, both for single and multi-response surrogate models, the entropy-based adaptive sampling approach leads to models that are more robust to the initial experimental design and at least as accurate (or better) when compared with other sampling techniques using the same number of sampling points.

Intuition and Inquiry

2012 ◽  
Vol 13 (1) ◽  
pp. 285-296
Author(s):  
Anand Vaidya ◽  
Keyword(s):  
Experimental Design ◽  
Recent Work ◽  
A Priori ◽  
Philosophical Methodology ◽  
Philosophical Inquiry

Recent work in philosophical methodology by experimental philosophers has brought to light a certain kind of skepticism about the role of intuitions in a priori philosophical inquiry. In this paper I turn attention away from a priori philosophical inquiry and on to the role of intuition in experimental design. I argue that even if we have reason to be skeptical about the role of intuition in a priori philosophical inquiry, we cannot remove intuition from inquiry altogether, because appeals to intuition are essential for experimental design.

Factor Analysis as an Experimental Technique

1967 ◽  
Vol 24 (3_suppl) ◽  
pp. 1289-1290
Author(s):  
A. C. Hall
Keyword(s):  
Factor Analysis ◽  
Experimental Design ◽  
Hypothesis Testing ◽  
Experimental Technique ◽  
Factor Space ◽  
Experimental Tool ◽  
Experimental Treatments

Factor analysis is not restricted to explanatory and classificatory studies but has its place as a hypothesis-testing experimental tool. A study in the field of experimental esthetics is briefly described. In this study, a set of orthogonal reference factors summarized the essential characteristics of a set of random ‘paintings.’ The vectors of Ss, who had ranked the paintings, were inserted into this factor space to test a prediction regarding differences in vector positions related to different experimental treatments. Two advantages of this type of experimental design over more usual classical procedures are suggested.

Hierarchy under anarchy: informal empire and the East German state

1995 ◽  
Vol 49 (4) ◽  
pp. 689-721 ◽  
Author(s):  
Alexander Wendt ◽  
Daniel Friedheim
Keyword(s):  
International Relations ◽  
Empirical Analysis ◽  
A Priori ◽  
International Relations Theory ◽  
International Governance ◽  
Constructivist Approach ◽  
German State ◽  
Informal Empire ◽  
East German ◽  
Formal Equality

Contemporary international politics embody a tension between formal equality and de facto inequality. States recognize each other as sovereign equals, yet the strong still push around the weak. Among the structures that reflect this tension are informal empires. The dominant assumptions in mainstream international relations theory, materialism and rationalism, privilege the formal equality of states in informal empires a priori: materialism by assuming that authority relations cannot exist between sovereign states; rationalism by assuming that states are sovereign over their own interests. A constructivist approach allows one to explore the hypothesis that transnational authority structures construct state identities and interests. An empirical analysis of the Soviet-East German relationship supports this hypothesis, which raises questions about the emerging study of international governance.

scholarly journals The optimization of leased line distribution at the EDGE of local access network via WAN convergence network

2019 ◽  
Vol 16 (1) ◽  
pp. 333
Author(s):  
Nor Shahniza Kamal Bashah ◽  
Nor Haizon Husin ◽  
Syaripah Ruzaini Syed Aris ◽  
Norjansalika Janom ◽  
Noor Habibah Arshad
Keyword(s):  
Network Design ◽  
Access Network ◽  
Digital Data ◽  
Network Resources ◽  
Network Resource ◽  
Multiple Networks ◽  
Local Access ◽  
And Control ◽  
Line Network ◽  
Convergence Network

Managing the multiple services of the leased line at the same location is quite critical especially when the resource become highly utilized. Bundling the several network resource components into a one box by simplifying the multiple networks to a single network can help to reduce the utilization of network resources. This paper presents a study on optimiziation of leased line distribution at the EDGE of Local Access Network via WAN convergence network. In this study, a WAN Convergence Network is designed which intends to use only a single leased line network in a location rather than multiple leased lines. It is using a simple concept of SDH structured which channelized the time slots and control the transmission line. The time slots will be relocated from the multiple leased lines into a WAN Convergence Network and it will be de-multiplexed through the Data Circuit Terminating Equipment (DCE) at the customer premises. The WAN Convergence Network design starts from the Digital Data Network (DDN) until the DCE which includes the Local Access Network. This approach will be able to save the network resource especially the time slots, cable port, DCE and consequently avoid adding new network infrastructure. This research will result to the new network design which offer multiple leased line networks at the customer end by using only one dedicated leased line network namely WAN Convergence Network.

OPTIMAL EXPERIMENTAL DESIGN FOR STRUCTURE CHARACTERIZATION OF BIODEGRADATION MODELS: ON-LINE IMPLEMENTATION IN A RESPIROGRAPHIC BIOSENSOR

1994 ◽  
Vol 30 (4) ◽  
pp. 243-253 ◽  
Author(s):  
P. Vanrolleghem ◽  
M. Van Daele
Keyword(s):  
Experimental Design ◽  
A Priori ◽  
Treatment Plant ◽  
Model Identification ◽  
Structure Characterization ◽  
Optimal Experimental Design ◽  
Process Conditions ◽  
Model Structure ◽  
Characterization Methods ◽  
On Line

The interaction between activated sludge and a wastewater is subject to important cbanges. This is reflected not only in changing biokinetic parameters but also in changing model structures. The need to select the ‘ right’ model structure in a reliable way on the basis of respirographic data provided by on-line sensors imposes serious real-time constraints on the methods used. First of all, fast structure characterization methods are presented allowing us to track the model structure on-line. Since these so-called a priori methods are less computing intensive, they can be at the basis of optimal experimental design calculations that can be performed on-line. This allows us to maintain the quality of the overall model identification under the changing process conditions of a wastewater treatment plant. Two applications of Optimal Experimental Design are given.

scholarly journals On-Line Optimal Input Design Increases the Efficiency and Accuracy of the Modelling of an Inducible Synthetic Promoter

Processes ◽  
2018 ◽  
Vol 6 (9) ◽  
pp. 148 ◽  
Author(s):  
Lucia Bandiera ◽  
Zhaozheng Hou ◽  
Varun Kothamachu ◽  
Eva Balsa-Canto ◽  
Peter Swain ◽  
...  
Keyword(s):  
Experimental Design ◽  
A Priori ◽  
Inducible Promoter ◽  
Optimal Experimental Design ◽  
Parameter Inference ◽  
Synthetic Gene Circuits ◽  
Input Design ◽  
On Line

Synthetic biology seeks to design biological parts and circuits that implement new functions in cells. Major accomplishments have been reported in this field, yet predicting a priori the in vivo behaviour of synthetic gene circuits is major a challenge. Mathematical models offer a means to address this bottleneck. However, in biology, modelling is perceived as an expensive, time-consuming task. Indeed, the quality of predictions depends on the accuracy of parameters, which are traditionally inferred from poorly informative data. How much can parameter accuracy be improved by using model-based optimal experimental design (MBOED)? To tackle this question, we considered an inducible promoter in the yeast S. cerevisiae. Using in vivo data, we re-fit a dynamic model for this component and then compared the performance of standard (e.g., step inputs) and optimally designed experiments for parameter inference. We found that MBOED improves the quality of model calibration by ∼60%. Results further improve up to 84 % when considering on-line optimal experimental design (OED). Our in silico results suggest that MBOED provides a significant advantage in the identification of models of biological parts and should thus be integrated into their characterisation.

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