885 research outputs found
Let Your CyberAlter Ego Share Information and Manage Spam
Almost all of us have multiple cyberspace identities, and these {\em
cyber}alter egos are networked together to form a vast cyberspace social
network. This network is distinct from the world-wide-web (WWW), which is being
queried and mined to the tune of billions of dollars everyday, and until
recently, has gone largely unexplored. Empirically, the cyberspace social
networks have been found to possess many of the same complex features that
characterize its real counterparts, including scale-free degree distributions,
low diameter, and extensive connectivity. We show that these topological
features make the latent networks particularly suitable for explorations and
management via local-only messaging protocols. {\em Cyber}alter egos can
communicate via their direct links (i.e., using only their own address books)
and set up a highly decentralized and scalable message passing network that can
allow large-scale sharing of information and data. As one particular example of
such collaborative systems, we provide a design of a spam filtering system, and
our large-scale simulations show that the system achieves a spam detection rate
close to 100%, while the false positive rate is kept around zero. This system
has several advantages over other recent proposals (i) It uses an already
existing network, created by the same social dynamics that govern our daily
lives, and no dedicated peer-to-peer (P2P) systems or centralized server-based
systems need be constructed; (ii) It utilizes a percolation search algorithm
that makes the query-generated traffic scalable; (iii) The network has a built
in trust system (just as in social networks) that can be used to thwart
malicious attacks; iv) It can be implemented right now as a plugin to popular
email programs, such as MS Outlook, Eudora, and Sendmail.Comment: 13 pages, 10 figure
What is the right theory for Anderson localization of light?
Anderson localization of light is traditionally described in analogy to
electrons in a random potential. Within this description the disorder strength
-- and hence the localization characteristics -- depends strongly on the
wavelength of the incident light. In an alternative description in analogy to
sound waves in a material with spatially fluctuating elastic moduli this is not
the case. Here, we report on an experimentum crucis in order to investigate the
validity of the two conflicting theories using transverse-localized optical
devices. We do not find any dependence of the observed localization radii on
the light wavelength. We conclude that the modulus-type description is the
correct one and not the potential-type one. We corroborate this by showing that
in the derivation of the traditional, potential-type theory a term in the wave
equation has been tacititly neglected. In our new modulus-type theory the wave
equation is exact. We check the consistency of the new theory with our data
using a field-theoretical approach (nonlinear sigma model)
Synthetic Order Data Generator for Picking Data
Sample data are in high demand for testing and benchmarking purposes. Like many other fields, warehousing and specifically order picking process are not exempt from the need for sample data. Sample data are used in order picking pro- cesses as a way of testing new methodologies such as new routing and new storage allocation approaches. Unfortunately, access to real order picking data is limited because of confidentiality and privacy issues which make it difficult to obtain practical results from the new methodologies. On the other hand, order data follows a highly complex and correlated structure that cannot be easily extracted and replicated. We propose a two-part synthetic data generator that extracts and mimics the general fabric of a set of real data and produces a conceptually unlimited number of orders with any number of SKUs while keeping the structure largely intact. Such data can fill the gap of missing data in order picking process benchmarking
Modular Self-Reconfigurable Robot Systems
The field of modular self-reconfigurable robotic systems addresses the design, fabrication, motion planning, and control of autonomous kinematic machines with variable morphology. Modular self-reconfigurable systems have the promise of making significant technological advances to the field of robotics in general. Their promise of high versatility, high value, and high robustness may lead to a radical change in automation. Currently, a number of researchers have been addressing many of the challenges. While some progress has been made, it is clear that many challenges still exist. By illustrating several of the outstanding issues as grand challenges that have been collaboratively written by a large number of researchers in this field, this article has shown several of the key directions for the future of this growing fiel
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