275 research outputs found
Assessing and Remedying Coverage for a Given Dataset
Data analysis impacts virtually every aspect of our society today. Often,
this analysis is performed on an existing dataset, possibly collected through a
process that the data scientists had limited control over. The existing data
analyzed may not include the complete universe, but it is expected to cover the
diversity of items in the universe. Lack of adequate coverage in the dataset
can result in undesirable outcomes such as biased decisions and algorithmic
racism, as well as creating vulnerabilities such as opening up room for
adversarial attacks.
In this paper, we assess the coverage of a given dataset over multiple
categorical attributes. We first provide efficient techniques for traversing
the combinatorial explosion of value combinations to identify any regions of
attribute space not adequately covered by the data. Then, we determine the
least amount of additional data that must be obtained to resolve this lack of
adequate coverage. We confirm the value of our proposal through both
theoretical analyses and comprehensive experiments on real data.Comment: in ICDE 201
RRR: Rank-Regret Representative
Selecting the best items in a dataset is a common task in data exploration.
However, the concept of "best" lies in the eyes of the beholder: different
users may consider different attributes more important, and hence arrive at
different rankings. Nevertheless, one can remove "dominated" items and create a
"representative" subset of the data set, comprising the "best items" in it. A
Pareto-optimal representative is guaranteed to contain the best item of each
possible ranking, but it can be almost as big as the full data. Representative
can be found if we relax the requirement to include the best item for every
possible user, and instead just limit the users' "regret". Existing work
defines regret as the loss in score by limiting consideration to the
representative instead of the full data set, for any chosen ranking function.
However, the score is often not a meaningful number and users may not
understand its absolute value. Sometimes small ranges in score can include
large fractions of the data set. In contrast, users do understand the notion of
rank ordering. Therefore, alternatively, we consider the position of the items
in the ranked list for defining the regret and propose the {\em rank-regret
representative} as the minimal subset of the data containing at least one of
the top- of any possible ranking function. This problem is NP-complete. We
use the geometric interpretation of items to bound their ranks on ranges of
functions and to utilize combinatorial geometry notions for developing
effective and efficient approximation algorithms for the problem. Experiments
on real datasets demonstrate that we can efficiently find small subsets with
small rank-regrets
Responsible Scoring Mechanisms Through Function Sampling
Human decision-makers often receive assistance from data-driven algorithmic
systems that provide a score for evaluating objects, including individuals. The
scores are generated by a function (mechanism) that takes a set of features as
input and generates a score.The scoring functions are either machine-learned or
human-designed and can be used for different decision purposes such as ranking
or classification.
Given the potential impact of these scoring mechanisms on individuals' lives
and on society, it is important to make sure these scores are computed
responsibly. Hence we need tools for responsible scoring mechanism design. In
this paper, focusing on linear scoring functions, we highlight the importance
of unbiased function sampling and perturbation in the function space for
devising such tools. We provide unbiased samplers for the entire function
space, as well as a -vicinity around a given function.
We then illustrate the value of these samplers for designing effective
algorithms in three diverse problem scenarios in the context of ranking.
Finally, as a fundamental method for designing responsible scoring mechanisms,
we propose a novel approach for approximating the construction of the
arrangement of hyperplanes. Despite the exponential complexity of an
arrangement in the number of dimensions, using function sampling, our algorithm
is linear in the number of samples and hyperplanes, and independent of the
number of dimensions
Spin Filtering and Entanglement Swapping through Coherent Evolution of a Single Quantum Dot
We exploit the non-dissipative dynamics of a pair of electrons in a large
square quantum dot to perform singlet-triplet spin measurement through a single
charge detection and show how this may be used for entanglement swapping and
teleportation. The method is also used to generate the AKLT ground state, a
further resource for quantum computation. We justify, and derive analytic
results for, an effective charge-spin Hamiltonian which is valid over a wide
range of parameters and agrees well with exact numerical results of a realistic
effective-mass model. Our analysis also indicates that the method is robust to
choice of dot-size and initialization errors, as well as decoherence introduced
by the hyperfine interaction.Comment: 5 pages, 3 figure
Numerical Solution of Some Nonlinear Volterra Integral Equations of the First Kind
In this paper, the solving of a class of the nonlinear Volterra integral equations (NVIE) of the first kind is investigated. Here, we convert NVIE of the first kind to a linear equation of the second kind. Then we apply the operational Tau method to the problem and prove convergence of the presented method. Finally, some numerical examples are given to show the accuracy of the method
On Obtaining Stable Rankings
Decision making is challenging when there is more than one criterion to
consider. In such cases, it is common to assign a goodness score to each item
as a weighted sum of its attribute values and rank them accordingly. Clearly,
the ranking obtained depends on the weights used for this summation. Ideally,
one would want the ranked order not to change if the weights are changed
slightly. We call this property {\em stability} of the ranking. A consumer of a
ranked list may trust the ranking more if it has high stability. A producer of
a ranked list prefers to choose weights that result in a stable ranking, both
to earn the trust of potential consumers and because a stable ranking is
intrinsically likely to be more meaningful. In this paper, we develop a
framework that can be used to assess the stability of a provided ranking and to
obtain a stable ranking within an "acceptable" range of weight values (called
"the region of interest"). We address the case where the user cares about the
rank order of the entire set of items, and also the case where the user cares
only about the top- items. Using a geometric interpretation, we propose
algorithms that produce stable rankings. In addition to theoretical analyses,
we conduct extensive experiments on real datasets that validate our proposal
A novel compact fractal UWB antenna with triple reconfigurable notch reject bands applications
A compact, circular UWB fractal antenna with triple reconfigurable notch rejection bands is proposed. It rejects the crowded frequency bands WiMAX, WLAN and X band interferences produced in UWB communication systems. The proposed fractal structure consists of a basic circular patch with circular fractal iterations. By employing this new structure of fractals, the overall size of antenna is reduced 53% to 21 × 25 mm, in comparison with traditional circular monopole antenna. The implemented antenna operates at 3.1–10 GHz. Re-configurability is realized by designing slots and split ring resonators in desired frequencies with the attached PIN diodes. WLAN band rejection was realized by creating a pair of optimized L-shaped slots in the ground plane. By etching a split ring resonator and a U-shaped slot, X and WiMAX bands were also rejected. Furthermore, by attaching diodes to aforementioned slots and designating the diodes on/off, different bands can be included or rejected. In time domain, the antenna properties are evaluated by a figure of merit called fidelity factor. Finally, the antenna properties are measured in anechoic chamber and the results agrees with simulation findings
A dynamic and context-aware semantic mediation service for discovering and fusion of heterogeneous sensor data
Sensors play an increasingly critical role in capturing and distributing observations of phenomena in our environment. The vision of the semantic sensor web is to enable the interoperability of various applications that use sensor data provided by semantically heterogeneous sensor services. However, several challenges still need to be addressed to achieve this vision. More particularly, mechanisms that can support context-aware semantic mapping and that can adapt to the dynamic metadata of sensors are required. Semantic mapping for the sensor web is required to support sensor data fusion, sensor data discovery and retrieval, and automatic semantic annotation, to name only a few tasks. This paper presents a context-aware ontology-based semantic mediation service for heterogeneous sensor services. The semantic mediation service is context-aware and dynamic because it takes into account the real-time variability of thematic, spatial, and temporal elements that describe sensor data in different contexts. The semantic mediation service integrates rule-based reasoning to support the resolution of semantic heterogeneities. An application scenario is presented showing how the semantic mediation service can improve sensor data interpretation, reuse, and sharing in static and dynamic settings
A survey on some risk factors and evaluation of their impacts on streptococcosis in rainbow trout farms in some provinces in Iran (Mazandaran, Fars)
One of the most important bacterial fish diseases which has caused some outbreaks in rainbow trout farms in Iran is streptococcusis. The farmers were suffering from huge economic losses due to the disease outbreaks in different rainbow trout farms in Iran. The aim of our study was to determine rate of streptococcusis incidence in different stage of growth in farmed rainbow trout in Mazandaran and Fars province. Fish and water samples were randomly collected and measured randomly in selected farms, monthly throughout a year. After clinical observations, Isolation and recognition of strep strains were made using biochemical and molecular tests. Some Environmental factors include Nitrate, Nitrite, Temperature, pH, Ammonia and DO measure during sampling periods. According to our results incidence of disease in juvenile is more than growers. Some samples showed clinical signs of streptococcusis without strep. contamination. Main isolated strain were S. iniae and S. garviea and S. uberis recognized for first time in east of Mazandaran province (Haraz River). Incidence of streptococcusis in rainbow trout affected by fluctuation of Nitrite, temperature and DO. Management of these factors can decrease rate of disease outbreaks
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