Reducing Opinion Echo-Chambers by Intelligent Placement of Moderate-Minded Agents

In the era of social media, people frequently share their own opinions online on various issues and also in the way, get exposed to others' opinions. Be it for selective exposure of news feed recommendation algorithms or our own inclination to listen to opinions that support ours, the result is that we get more and more exposed to opinions closer to ours. Further, any population is inherently heterogeneous i.e. people will hold a varied range of opinions regarding a topic and showcase a varied range of openness to get influenced by others. In this paper, we demonstrate the different behavior put forward by open- and close-minded agents towards an issue, when allowed to freely intermix and communicate. We have shown that the intermixing among people leads to formation of opinion echo chambers i.e. a small closed network of people who hold similar opinions and are not affected by opinions of people outside the network. Echo chambers are evidently harmful for a society because it inhibits free healthy communication among all and thus, prevents exchange of opinions, spreads misinformation and increases extremist beliefs. This calls for reduction in echo chambers, because a total consensus of opinion is neither possible nor is welcome. We show that the number of echo chambers depends on the number of close-minded agents and cannot be lessened by increasing the number of open-minded agents. We identify certain 'moderate'-minded agents, who possess the capability of manipulating and reducing the number of echo chambers. The paper proposes an algorithm for intelligent placement of moderate-minded agents in the opinion-time spectrum by which the opinion echo chambers can be maximally reduced. With various experimental setups, we demonstrate that the proposed algorithm fares well when compared to placement of other agents (open- or close-minded) and random placement of 'moderate'-minded agents

In Vivo Outer Hair Cell Length Changes Expose the Active Process in the Cochlea

BACKGROUND: Mammalian hearing is refined by amplification of the sound-evoked vibration of the cochlear partition. This amplification is at least partly due to forces produced by protein motors residing in the cylindrical body of the outer hair cell. To transmit power to the cochlear partition, it is required that the outer hair cells dynamically change their length, in addition to generating force. These length changes, which have not previously been measured in vivo, must be correctly timed with the acoustic stimulus to produce amplification. METHODOLOGY/PRINCIPAL FINDINGS: Using in vivo optical coherence tomography, we demonstrate that outer hair cells in living guinea pigs have length changes with unexpected timing and magnitudes that depend on the stimulus level in the sensitive cochlea. CONCLUSIONS/SIGNIFICANCE: The level-dependent length change is a necessary condition for directly validating that power is expended by the active process presumed to underlie normal hearing

Optical devices for high speed optical communications

For high speed optical communications, we need lasers and modulators that can operate at high speeds. In lasers and modulators used for high speed communications, various properties, such as, the spectral width under modulation, and relaxation oscillation frequency, determine the high speed performance of these devices. It is also important to study the various multiplexing and demultiplexing techniques used to make these already fast devices operate at even higher rates. This thesis reports a study of sources for high speed communication systems and their application in very high speed time division multiplexed transmissions. ^ Semiconductor sources with integrated electroabsorption modulators and distributed feedback lasers (EML) are important for high speed (2.5 Gb/s and higher) transmission systems. These devices have very low spectral width under modulation which reduces the effect of fiber chromatic dispersion. Various properties, such as, the linewidth enhancement factor (α-factor) and relative intensity noise (RIN) of EMLs are extensively studied. Modulation doping of a multi-quantum-well laser, can reduce the α-factor and the relative intensity noise, and increase the relaxation oscillation frequency. We have investigated theoretically these various properties of a modulation doped InGaAsP quantum well (QW) laser emitting at 1.55 μm. Rational harmonic mode-locking is potentially an important source for generation of high frequency pulse trains needed for ultra-high speed networks. But in order to use these pulses in optical communication we need to stabilize them. We have studied a new method to stabilize a fiberlaser. ^ Ultrahigh-speed optical time-division-multiplexed (TDM) transmission technologies are essential to construct the ultrahigh-speed all-optical networks needed in the multimedia era. The demultiplexing technique will be realized using the LiNbO3 Mach-zender modulators.

Extracting scattering coefficient and anisotropy factor of tissue using optical coherence tomography

Determination of tissue optical properties is important as it will lead to better design of optical diagnostic tools, improvement in laser therapy, photo dynamic therapy dosimetry, drug pharmacokinetics, etc. We have developed a theoretical model for OCT signal using Monte Carlo simulation that allows us to fit values extracted from the OCT signal, namely, reflectance, ρ, and the total optical attenuation coefficient, μt, to obtain optical properties of tissue (scattering coefficient, μs, and anisotropy factor, g). Using this method we have extracted optical properties of different tissue types, e.g., skin, muscle, liver, and brain of mouse. © 2012 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE)