Segregation of Heterogeneous Robotics Swarms via Convex Optimization

2016 ◽  
Author(s):  
Victoria Edwards ◽  
Paulo Rezeck ◽  
Luiz Chaimowicz ◽  
M. Ani Hsieh
Keyword(s):  
Convex Optimization ◽  
Division Of Labor ◽  
Optimization Approach ◽  
Control Methods ◽  
Natural Phenomena ◽  
The Past ◽  
Robotic Swarms ◽  
Theoretical Results

The division of labor amongst a heterogeneous swarm of robots increases the range and sophistication of the tasks the swarm can accomplish. To efficiently execute a task the swarm of robots must have some starting organization. Over the past decade segregation of robotic swarms has grown as a field of research drawing inspiration from natural phenomena such as cellular segregation. A variety of different approaches have been undertaken to devise control methods to organize a heterogeneous swarm of robots. In this work, we present a convex optimization approach to segregate a heterogeneous swarm into a set of homogeneous collectives. We present theoretical results that show our approach is guaranteed to achieve complete segregation and validate our strategy in simulation and experiments.

scholarly journals Optimising the AR Engraved Structure on Light-Guide Facets for a Wide Range of Wavelengths

Optics ◽  
2020 ◽  
Vol 2 (1) ◽  
pp. 25-42
Author(s):  
Ioseph Gurwich ◽  
Yakov Greenberg ◽  
Kobi Harush ◽  
Yarden Tzabari
Keyword(s):  
Theoretical Analysis ◽  
Light Guide ◽  
Spectral Band ◽  
Angular Range ◽  
The Past ◽  
Input And Output ◽  
Wide Range ◽  
The Given ◽  
Theoretical Results ◽  
Shape And Size

The present study is aimed at designing anti-reflective (AR) engraving on the input–output surfaces of a rectangular light-guide. We estimate AR efficiency, by the transmittance level in the angular range, determined by the light-guide. Using nano-engraving, we achieve a uniform high transmission over a wide range of wavelengths. In the past, we used smoothed conical pins or indentations on the faces of light-guide crystal as the engraved structure. Here, we widen the class of pins under consideration, following the physical model developed in the previous paper. We analyze the smoothed pyramidal pins with different base shapes. The possible effect of randomization of the pins parameters is also examined. The results obtained demonstrate optimized engraved structure with parameters depending on the required spectral range and facet format. The predicted level of transmittance is close to 99%, and its flatness (estimated by the standard deviation) in the required wavelengths range is 0.2%. The theoretical analysis and numerical calculations indicate that the obtained results demonstrate the best transmission (reflection) we can expect for a facet with the given shape and size for the required spectral band. The approach is equally useful for any other form and of the facet. We also discuss a simple way of comparing experimental and theoretical results for a light-guide with the designed input and output features. In this study, as well as in our previous work, we restrict ourselves to rectangular facets. We also consider the limitations on maximal transmission produced by the size and shape of the light-guide facets. The theoretical analysis is performed for an infinite structure and serves as an upper bound on the transmittance for smaller-size apertures.

scholarly journals Maximizing protein translation rate in the non-homogeneous ribosome flow model: a convex optimization approach

2014 ◽  
Vol 11 (100) ◽  
pp. 20140713 ◽  
Author(s):  
Gilad Poker ◽  
Yoram Zarai ◽  
Michael Margaliot ◽  
Tamir Tuller
Keyword(s):  
Synthetic Biology ◽  
Convex Optimization ◽  
Production Rate ◽  
Protein Production ◽  
Flow Model ◽  
Protein Translation ◽  
Optimization Approach ◽  
Initiation Rate ◽  
Translation Rate ◽  
Protein Production Rate

Translation is an important stage in gene expression. During this stage, macro-molecules called ribosomes travel along the mRNA strand linking amino acids together in a specific order to create a functioning protein. An important question, related to many biomedical disciplines, is how to maximize protein production. Indeed, translation is known to be one of the most energy-consuming processes in the cell, and it is natural to assume that evolution shaped this process so that it maximizes the protein production rate. If this is indeed so then one can estimate various parameters of the translation machinery by solving an appropriate mathematical optimization problem. The same problem also arises in the context of synthetic biology, namely, re-engineer heterologous genes in order to maximize their translation rate in a host organism. We consider the problem of maximizing the protein production rate using a computational model for translation–elongation called the ribosome flow model (RFM). This model describes the flow of the ribosomes along an mRNA chain of length n using a set of n first-order nonlinear ordinary differential equations. It also includes n + 1 positive parameters: the ribosomal initiation rate into the mRNA chain, and n elongation rates along the chain sites. We show that the steady-state translation rate in the RFM is a strictly concave function of its parameters. This means that the problem of maximizing the translation rate under a suitable constraint always admits a unique solution, and that this solution can be determined using highly efficient algorithms for solving convex optimization problems even for large values of n . Furthermore, our analysis shows that the optimal translation rate can be computed based only on the optimal initiation rate and the elongation rate of the codons near the beginning of the ORF. We discuss some applications of the theoretical results to synthetic biology, molecular evolution, and functional genomics.

Anthropocene nostalgia for the 1980s in Netflix’s Stranger Things

2021 ◽  
Vol 40 (3) ◽  
pp. 233-247 ◽  
Author(s):  
Alicja Relidzyńska
Keyword(s):  
American Culture ◽  
Significant Alteration ◽  
Reconstructed Image ◽  
The Novel ◽  
Natural Phenomena ◽  
The Past ◽  
Distinctive Type

Expressions of nostalgia for the 1980s in contemporary American culture are diverse. The most interesting of them go beyond a wistful longing for the past. A complex ‘nostalgia trip’ offered by Netflix’s Stranger Things serves as a notable case study of a distinctive type of this sentiment. Instead of yearning for the restoration of previous times, it plays with past aesthetics in a critically articulate manner, effectively demythologizing the depicted decade. I argue that this significant alteration of the traditional sentiment stems largely from the recent acknowledgment of the Anthropocene and its irreversibility. This article aims to examine the peculiar, self-aware, paradoxical nostalgia, which is coloured by the current, Anthropocene-induced fears for the environment and, thus, our future. The analysis of Stranger Things – its thematics, genre, visuals and the meticulously reconstructed image of the presented era – draws parallels to the techniques employed by the ‘novel nostalgia’: bitter, ironic depiction of the past and references to natural phenomena. The study thus investigates the show at the intersection of contemporary nostalgia for the 1980s and the cultural repercussions of the Anthropocene. In so doing, it will unravel the innovation in the programme’s discourse on the 1980s decade in American culture.

The Battle over Patents

2021 ◽  
Keyword(s):  
Division Of Labor ◽  
Market Value ◽  
Historical Record ◽  
Free Rider ◽  
Property Right ◽  
Economic Surplus ◽  
Free Rider Problem ◽  
The Past ◽  
Inventive Activity ◽  
Patent Systems

Do patents facilitate or frustrate innovation? Lawyers, economists, and politicians who have staked out strong positions in this debate often attempt to validate their claims by invoking the historical record—but they typically get the history wrong. The purpose of this book is to get the history right by showing that patent systems are the product of contending interests at different points in production chains battling over economic surplus. The larger the potential surplus, the more extreme are the efforts of contending parties, now and in the past, to search out, generate, and exploit any and all sources of friction. Patent systems, as human creations, are therefore necessarily ridden with imperfections; nirvana is not on the menu. The most interesting intellectual issue is not how patent systems are imperfect, but why historically US-style patent systems have come to dominate all other methods of encouraging inventive activity. The answer offered by the essays in this volume is that they create a temporary property right that can be traded in a market, thereby facilitating a productive division of labor and making it possible for firms to transfer technological knowledge to one another by overcoming the free-rider problem. Precisely because the value of a patent does not inhere in the award itself but rather in the market value of the resulting property right, patent systems foster a decentralized ecology of inventors and firms that ceaselessly extends the frontiers of what is economically possible.

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