Evolution Of System Architectures Research Articles

'Distributed' vision and the architecture of animal visual systems.

More than a century of research, of which JEB has published a substantial selection, has highlighted the rich diversity of animal eyes. From these studies have emerged numerous examples of visual systems that depart from our own familiar blueprint, a single pair of lateral cephalic eyes. It is now clear that such departures are common, widespread and highly diverse, reflecting a variety of different eye types, visual abilities and architectures. Many of these examples have been described as 'distributed' visual systems, but this includes several fundamentally different systems. Here, I re-examine this term, suggest a new framework within which to evaluate visual system distribution in both spatial and functional senses, and propose a roadmap for future work. The various architectures covered by this term reflect three broad strategies that offer different opportunities and require different approaches for study: the duplication of functionally identical eyes, the expression of multiple, functionally distinct eye types in parallel and the use of dispersed photoreceptors to mediate visual behaviour without eyes. Within this context, I explore some of the possible implications of visual system architecture for how visual information is collected and integrated, which has remained conceptually challenging in systems with a large degree of spatial and/or functional distribution. I highlight two areas that should be prioritised in future investigations: the whole-organism approach to behaviour and signal integration, and the evolution of visual system architecture across Metazoa. Recent advances have been made in both areas, through well-designed ethological experiments and the deployment of molecular tools.

Direct imaging of exoplanets: Legacy and prospects

Understanding how giant and terrestrial planets form and evolve, what is their internal structure and that of their atmosphere, represents one of the major challenges of modern astronomy, which is directly connected to the ultimate search for life at the horizon 2030–2050. However, several astrophysical (understanding of the formation and physics of giant and terrestrial exoplanets), biological (identification of the best biomarkers) and technological (technical innovations for the new generations of telescopes and instruments) obstacles must be overcome. From the astrophysical point of view, it is indeed crucial to understand the mechanisms of formation and evolution of giant planets, including planet and disk interactions, which will completely sculpt the planetary architectures and thus dominate the formation of terrestrial planets, especially in regions around the host star capable of supporting life. It is also important to develop dedicated instrumentation and techniques to study in their totality the population of giant and terrestrial planets, but also to reveal in the near future the first biological markers of life in the atmospheres of terrestrial planets. In that perspective, direct imaging from ground-based observatories or in space is playing a central role in concert with other observing techniques. In this paper, I will briefly review the genesis of this observing technique, the main instrumental innovation and challenges, stellar targets and surveys, to then present the main results obtained so far about the physics and the mechanisms of formation and evolution of young giant planets and planetary system architectures. I will then present the exciting perspectives offered by the upcoming generation of planet imagers about to come online, particularly on the future extremely large telescopes. On the timescale of a human Life, we may well be witnessing the first discovery of an exoplanet and the first detection of indices of life in the atmosphere of a nearby exo-Earth!

The role of AUX1 during lateral root development in the domestication of the model C4 grass Setaria italica.

C4 photosynthesis increases the efficiency of carbon fixation by spatially separating high concentrations of molecular oxygen from Rubisco. The specialized leaf anatomy required for this separation evolved independently many times. The morphology of C4 root systems is also distinctive and adapted to support high rates of photosynthesis; however, little is known about the molecular mechanisms that have driven the evolution of C4 root system architecture. Using a mutant screen in the C4 model plant Setaria italica, we identify Siaux1-1 and Siaux1-2 as root system architecture mutants. Unlike in S. viridis, AUX1 promotes lateral root development in S. italica. A cell by cell analysis of the Siaux1-1 root apical meristem revealed changes in the distribution of cell volumes in all cell layers and a dependence of the frequency of protophloem and protoxylem strands on SiAUX1. We explore the molecular basis of the role of SiAUX1 in seedling development using an RNAseq analysis of wild-type and Siaux1-1 plants and present novel targets for SiAUX1-dependent gene regulation. Using a selection sweep and haplotype analysis of SiAUX1, we show that Hap-2412TT in the promoter region of SiAUX1 is an allele which is associated with lateral root number and has been strongly selected for during Setaria domestication.

Imaging local soil kinematics during the first days of maize root growth in sand

Maize seedlings are grown in Hostun sand with two different gradings and two different densities. The root-soil system is imaged daily for the first 8 days of plant growth with X-ray computed tomography. Segmentation, skeletonisation and digital image correlation techniques are used to analyse the evolution of the root system architecture, the displacement fields and the local strain fields due to plant growth in the soil. It is found that root thickness and root length density do not depend on the initial soil configuration. However, the depth of the root tip is strongly influenced by the initial soil density, and the number of laterals is impacted by grain size, which controls pore size, capillary rise and thus root access to water. Consequently, shorter root axes are observed in denser sand and fewer second order roots are observed in coarser sands. In all soil configurations tested, root growth induces shear strain in the soil around the root system, and locally, in the vicinity of the first order roots axis. Root-induced shear is accompanied by dilative volumetric strain close to the root body. Further away, the soil experiences dilation in denser sand and compaction in looser sand. These results suggest that the increase of porosity close to the roots can be caused by a mix of shear strain and steric exclusion.

AARIN: Affordable, accurate, reliable and innovative mechanism to protect a medical cyber-physical system using blockchain technology

The enhancement (in the past decade) in electronics devices/technology, a rise in most of the accidents concerning security and surveillance intruding the private lives of the users question the existing systems being used to combat this challenge wherein, the third-parties gather and handle large amounts of individual details. As part of the constant evolution of the cyber physical system architecture, one of the goals of our system is to reduce the latency time for enrollment of new information. Generally, the efficiency and benefit of a Cyber Physical Systems (CPS) depends heavily on interconnection of individual devices or nodes. Exchange of data and information relevant to an overall task or functionality is the key to many applications such as smart grids, smart cities, and many others. Trustworthiness of data is needed to make such systems (especially in MCPS systems) successful. To be able to fulfill policies to guarantee the safety of all entities within a Medical Cyber Physical Systems (MCPS) and to provide security measures to enforce these cryptographic solutions have to be embedded. This paper describes a decentralized e-healthcare application framework for personal data management that ensures that users own and access their data. This work proposes a novel mechanism to secure Medical Cyber Physical Systems (MCPS), i.e., as an automated access-control manager (including building trust in a third party). This work also integrates some features in security building blocks in ultra-small devices to provide essential properties to secure embedded systems.

Convergent evolution of root system architecture in two independently evolved lineages of weedy rice.

Root system architecture (RSA) is a critical aspect of plant growth and competitive ability. Here we used two independently evolved strains of weedy rice, a de-domesticated form of rice, to study the evolution of weed-associated RSA traits and the extent to which they evolve through shared or different genetic mechanisms. We characterised 98 two-dimensional and three-dimensional RSA traits in 671 plants representing parents and descendants of two recombinant inbred line populations derived from two weed×crop crosses. A random forest machine learning model was used to assess the degree to which root traits can predict genotype and the most diagnostic traits for doing so. We used quantitative trait locus (QTL) mapping to compare genetic architecture between the weed strains. The two weeds were distinguishable from the crop in similar and predictable ways, suggesting independent evolution of a 'weedy' RSA phenotype. Notably, comparative QTL mapping revealed little evidence for shared underlying genetic mechanisms. Our findings suggest that despite the double bottlenecks of domestication and de-domestication, weedy rice nonetheless shows genetic flexibility in the repeated evolution of weedy RSA traits. Whereas the root growth of cultivated rice may facilitate interactions among neighbouring plants, the weedy rice phenotype may minimise below-ground contact as a competitive strategy.

Xenacoelomorph Neuropeptidomes Reveal a Major Expansion of Neuropeptide Systems during Early Bilaterian Evolution

Neuropeptides are neurosecretory signaling molecules in protostomes and deuterostomes (together Nephrozoa). Little, however, is known about the neuropeptide complement of the sister group of Nephrozoa, the Xenacoelomorpha, which together form the Bilateria. Because members of the xenacoelomorph clades Xenoturbella, Nemertodermatida, and Acoela differ extensively in their central nervous system anatomy, the reconstruction of the xenacoelomorph and bilaterian neuropeptide complements may provide insights into the relationship between nervous system evolution and peptidergic signaling. Here, we analyzed transcriptomes of seven acoels, four nemertodermatids, and two Xenoturbella species using motif searches, similarity searches, mass spectrometry and phylogenetic analyses to characterize neuropeptide precursors and neuropeptide receptors. Our comparison of these repertoires with previously reported nephrozoan and cnidarian sequences shows that the majority of annotated neuropeptide GPCRs in cnidarians are not orthologs of specific bilaterian neuropeptide receptors, which suggests that most of the bilaterian neuropeptide systems evolved after the cnidarian–bilaterian evolutionary split. This expansion of more than 20 peptidergic systems in the stem leading to the Bilateria predates the evolution of complex nephrozoan organs and nervous system architectures. From this ancient set of neuropeptides, acoels show frequent losses that correlate with their divergent central nervous system anatomy. We furthermore detected the emergence of novel neuropeptides in xenacoelomorphs and their expansion along the nemertodermatid and acoel lineages, the two clades that evolved nervous system condensations. Together, our study provides fundamental insights into the early evolution of the bilaterian peptidergic systems, which will guide future functional and comparative studies of bilaterian nervous systems.

The Evolution of System Architectures: Products, Organizations, and Industries

The concept of architecture, broadly defined as the scheme underlying the arrangement of the components in a system, has been central to those study product innovation, organizational structure, an...

An Architecture‐based Enterprise Planning Process

AbstractThere is a need to augment the traditional enterprise portfolio management process with a more robust process for managing the evolution of enterprise, program and system architectures. These architectures need to evolve towards a desired end state that best meets the needs and concerns of various stakeholders for the enterprise and the extent and variety of systems under its purview. This paper describes a six‐step process for managing architectures under these conditions. It has been implemented at some large government agencies and is based on best practices from government and industry. This process is one of those essential to implementing the relatively new practice of enterprise systems engineering.

Software architecture evolution through evolvability analysis

Software evolvability is a multifaceted quality attribute that describes a software system's ability to easily accommodate future changes. It is a fundamental characteristic for the efficient implementation of strategic decisions, and the increasing economic value of software. For long life systems, there is a need to address evolvability explicitly during the entire software lifecycle in order to prolong the productive lifetime of software systems. However, designing and evolving software architectures are the challenging task. To improve the ability to understand and systematically analyze the evolution of software system architectures, in this paper, we describe software architecture evolution characterization, and propose an architecture evolvability analysis process that provides replicable techniques for performing activities to aim at understanding and supporting software architecture evolution. The activities are embedded in: (i) the application of a software evolvability model; (ii) a structured qualitative method for analyzing evolvability at the architectural level; and (iii) a quantitative evolvability analysis method with explicit and quantitative treatment of stakeholders’ evolvability concerns and the impact of potential architectural solutions on evolvability. The qualitative and quantitative assessments manifested in the evolvability analysis process have been applied in two large-scale industrial software systems at ABB and Ericsson, with experiences and reflections described.

Noise in biological circuits

Noise biology focuses on the sources, processing, and biological consequences of the inherent stochastic fluctuations in molecular transitions or interactions that control cellular behavior. These fluctuations are especially pronounced in small systems where the magnitudes of the fluctuations approach or exceed the mean value of the molecular population. Noise biology is an essential component of nanomedicine where the communication of information is across a boundary that separates small synthetic and biological systems that are bound by their size to reside in environments of large fluctuations. Here we review the fundamentals of the computational, analytical, and experimental approaches to noise biology. We review results that show that the competition between the benefits of low noise and those of low population has resulted in the evolution of genetic system architectures that produce an uneven distribution of stochasticity across the molecular components of cells and, in some cases, use noise to drive biological function. We review the exact and approximate approaches to gene circuit noise analysis and simulation, and review many of the key experimental results obtained using flow cytometry and time-lapse fluorescent microscopy. In addition, we consider the probative value of noise with a discussion of using measured noise properties to elucidate the structure and function of the underlying gene circuit. We conclude with a discussion of the frontiers of and significant future challenges for noise biology.

Consistent policy enforcement in distributed systems using mobile policies

This paper briefly traces the evolution of information system architectures from mainframe-connected terminals to distributed multi-tier architectures. It presents the challenges facing developers of multi-tier information systems in providing effective consistent data policy enforcement, such as access control in these architectures. Finally, it introduces “Mobile Policy” (MoP) as a potential solution and presents a framework for using mobile policy in the business logic tier of multi-tier information systems.

A hypermedia-based group decision support system to support collaborative medical decision-making

The systematic evolution of a hypermedia-based group decision support system (GDSS) architecture to support collaborative medical decision-making (MDM) is presented in this paper. This GDSS is for subsequent use by designers and researchers in the GDSS/medical informatics arena who can use several or parts of the presented architecture for effecting collaborative MDM. The GDSS design also supports various levels of inference-based medical support ranging from the lower diagnostic levels to the higher clinical levels. The evolution of this architecture incorporated systematic research and investigation of the basic elements of the MDM process, associated procedures, tools and the potential impact of different characteristics of medical groups. This architecture incorporates clinical reasoning and problem-solving features identified through an analysis of the schools of MDM from a GDSS perspective. Identification of inadequacies from a collaborative MDM perspective of existing GDSS research frameworks and architectures has also influenced current architecture development. The inexact nature of cognitive processes that are inherent in MDM necessitated the incorporation of “cognitive-aid structures” and the “cognitive appropriation processes” architectural components. The MEDICALWARE™ 1 1 MEDICALWARE is a trademark of Quantum Enterprises, NJ. component, integrated with a GDSS is designed to provide problem-solving support, access to clinical algorithms and procedures, expert inference support and several MDM support tools with hypermedia functionality. Hypertext templates with semantic nodes and links provide group members the ability to modify templates for accommodating expected or unexpected variations in decision-making criterion in handling a clinical case. Group members can thus ascertain whether they have followed all required procedures and algorithms, and modify diagnostic procedures if necessary. Several facets of the GDSS architecture can be prototyped and field-tested, incorporating clinical algorithms and related diagnostic support tools. The GDSS architecture presented can also be used for empirical studies in collaborative MDM.

Processes driving the networked economy

The authors propose that an organic workflow-process technology will power the evolution of information system architectures. The authors outline three likely stages of architectural evolution in the context of a networked economy and discuss critical gaps in the current technology with respect to their envisioned future.

Genome system architecture and natural genetic engineering in evolution.

Molecular genetics teaches three lessons relevant to the nature of genetic change during evolution: (1) Genomes are organized as hierarchies of composite systems (multidomain protein-coding sequences; functional loci made up of regulatory, coding, processing, and intervening sequences; and multilocus regulons and replicons) interconnected and organized into specific "system architectures" by repetitive DNA elements. (2) Genetic change often occurs via natural genetic engineering systems (cellular biochemical functions, such as recombination complexes, topoisomerases, and mobile elements, capable of altering DNA sequence information and joining together different genomic components). (3) The activity of natural genetic systems is regulated by cellular control circuits with respect to the timing, activity levels, and specificities of DNA rearrangements (e.g., adaptive mutation, Ty element mobility, and P factor insertions). These three lessons provide plausible molecular explanations for the episodic, multiple, nonrandom DNA rearrangements needed to account for the evolution of novel genomic system architectures and complex multilocus adaptations. This molecular genetic perspective places evolutionary change in the biologically responsive context of cellular biochemistry.

Lightwave Device Technology

High-performance, reliable lightwave devices are the foundation of the current lightwave revolution in communications. The advances in semiconductor laser, LED (light-emitting diode), and photodetector technologies and their role in the evolution of lightwave system architecture are described.

Computer communication standards

This is one of a series of reports on the state of affairs in the communication standards arena. The development of high-quality standards for networking services, protocols, and interfaces has taken on a new urgency in the past few years with the rapid evolution of communication technologies and system architectures that are uniquely suited, both technically and economically, to the construction of distributed application environments. Unfortunately, despite the growing importance of these standards to a very large community of computer system builders and users, the standards-making process is not widely understood; it has a language of its own, and its metabolism is extremely confusing to those who are not actively involved. These reports are motivated by the belief that better standards - timelier, more relevant, and closer to the state of the art - will result from a more widely informed community of interest. Communication standards are produced by a large number of domestic and international organizations, most of which have meaningless, unpronounceable names that look like something out of the Dewey Decimal system. As a further complication, the organizations and their relationships to one another change as the standards-making process evolves. The most important telecommunications standards organization, the International Telephone and Telegraph Consultative Committee (CCITT), disbands its study groups every four years, holds a plenary meeting (the 8th CCITT Plenary Assembly was held on October 8-19, 1984), and creates new study groups for the next four-year period. The other major communications standards body, Technical Committee 97 of the International Organization for Standardization (ISO), has just completed a major reorganization of its subcommittees, which particularly affects the groups working on Open Systems Interconnection (OSI) standards. This report contains a new ISO TC97 organization chart, which supercedes the corresponding chart in the first of these reports (CCR 13:1, January, 1983). A new CCITT organization chart will appear in the next issue of CCR. Summary descriptions of what some of the standards groups are doing, arranged by subject, begin below. Needless to say, there are many other standards activities that for reasons of limited space are not mentioned.