195 research outputs found

    Robust Architectures for Embedded Wireless Network Control and Actuation

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    Networked Cyber-Physical Systems are fundamentally constrained by the tight coupling and closed-loop control of physical processes. To address actuation in such closed-loop wireless control systems there is a strong need to re-think the communication architectures and protocols for reliability, coordination and control. We introduce the Embedded Virtual Machine (EVM), a programming abstraction where controller tasks with their control and timing properties are maintained across physical node boundaries and functionality is capable of migrating to the most competent set of physical controllers. In the context of process and discrete control, an EVM is the distributed runtime system that dynamically selects primary-backup sets of controllers given spatial and temporal constraints of the underlying wireless network. EVM-based algorithms allow network control algorithms to operate seamlessly over less reliable wireless networks with topological changes. They introduce new capabilities such as predictable outcomes during sensor/actuator failure, adaptation to mode changes and runtime optimization of resource consumption. An automated design flow from Simulink to platform-independent domain specific languages, and subsequently, to platform-dependent code generation is presented. Through case studies in discrete and process control we demonstrate the capabilities of EVM-based wireless network control systems

    An organotypic slice culture model of chronic white matter injury with maturation arrest of oligodendrocyte progenitors

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    <p>Abstract</p> <p>Background</p> <p>CNS myelination disturbances commonly occur in chronic white matter lesions in neurodevelopmental and adult neurological disorders. Recent studies support that myelination failure can involve a disrupted cellular repair mechanism where oligodendrocyte (OL) progenitor cells (OPCs) proliferate in lesions with diffuse astrogliosis, but fail to fully differentiate to mature myelinating OLs. There are no <it>in vitro </it>models that reproduce these features of myelination failure.</p> <p>Results</p> <p>Forebrain coronal slices from postnatal day (P) 0.5/1 rat pups were cultured for 1, 5, or 9 days <it>in vitro </it>(DIV). Slices rapidly exhibited diffuse astrogliosis and accumulation of the extracellular matrix glycosaminoglycan hyaluronan (HA), an inhibitor of OPC differentiation and re-myelination. At 1 DIV ~1.5% of Olig2<sup>+ </sup>OLs displayed caspase-3 activation, which increased to ~11.5% by 9 DIV. At 1 DIV the density of PDGFRα<sup>+ </sup>and PDGFRα<sup>+</sup>/Ki67<sup>+ </sup>OPCs were significantly elevated compared to 0 DIV (<it>P </it>< 0.01). Despite this proliferative response, at 9 DIV ~60% of white matter OLs were late progenitors (preOLs), compared to ~7% in the postnatal day 10 rat (<it>P </it>< 0.0001), consistent with preOL maturation arrest. Addition of HA to slices significantly decreased the density of MBP<sup>+ </sup>OLs at 9 DIV compared to controls (217 ± 16 <it>vs. </it>328 ± 17 cells/mm<sup>2</sup>, respectively; <it>P </it>= 0.0003), supporting an inhibitory role of HA in OL lineage progression in chronic lesions.</p> <p>Conclusions</p> <p>Diffuse white matter astrogliosis and early OPC proliferation with impaired OL maturation were reproduced in this model of myelination failure. This system may be used to define mechanisms of OPC maturation arrest and myelination failure related to astrogliosis and HA accumulation.</p

    A Survey on Integrated Circuit Trojans

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    Traditionally, computer security has been associated with the software security, or the information-data security. Surprisingly, the hardware on which the software executes or the information stored-processed-transmitted has been assumed to be a trusted base of security. The main building blocks of any electronic device are Integrated circuits (ICs) which form the fabric of a computer system. Lately, the use of ICs has expanded from handheld calculators and personal computers (PCs) to smartphones, servers, and Internet-of-Things (IoT) devices. However, this significant growth in the IC market created intense competition among IC vendors, leading to new trends in IC manufacturing. System-on-chip (SoC) design based on intellectual property (IP), a globally spread supply chain of production and distribution of ICs are the foremost of these trends. The emerging trends have resulted in many security and trust weaknesses and vulnerabilities, in computer systems. This includes Hardware Trojans attacks, side-channel attacks, Reverse-engineering, IP piracy, IC counterfeiting, micro probing, physical tampering, and acquisition of private or valuable assets by debugging and testing. IC security and trust vulnerabilities may cause loss of private information, modified/altered functions, which may cause a great economical hazard and big damage to society. Thus, it is crucial to examine the security and trust threats existing in the IC lifecycle and build defense mechanisms against IC Trojan threats. In this article, we examine the IC supply chain and define the possible IC Trojan threats for the parties involved. Then we survey the latest progress of research in the area of countermeasures against the IC Trojan attacks and discuss the challenges and expectations in this area. Keywords: IC supply chain, IC security, IP privacy, hardware trojans, IC trojans DOI: 10.7176/CEIS/12-2-01 Publication date: April 30th 202

    Conflict in Virtual Teams: a bibliometric analysis, systematic review, and research agenda

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    Design/methodology/approach: A dataset of 107 relevant papers on the topic was retrieved using the Web of Science Core Collection database covering a period ranging from 2001 to 2019. A comparative bibliometric analysis consisting of the integration of results from the citation, co-citation, and bibliographic coupling was performed to identify the most influential papers. The systematic literature review complemented the bibliometric results by clustering the most influential papers. Purpose: The purpose of this study is to map the intellectual structure of the research concerning conflict and conflict management in virtual teams (VT), to contribute to the further integration of knowledge among different streams of research, and to develop an interpretative framework to stimulate future research. Findings: The results revealed different intellectual structures across several types of analyses. Despite such differences, 41 papers resulted as the most impactful and provided evidence of the emergence of five thematic clusters: trust, performance, cultural diversity, knowledge management, and team management. Research limitations/implications: Based on the bibliometric analyses an interpretative research agenda has been developed that unveils the main future research avenues. The paper also offers important theoretical contributions by systematizing knowledge on conflict in identifying VTs. Managerial contributions in the form of the identification of best practices are also developed to guide conflict management in VTs. Originality/value: The uniqueness of this paper is related to its effort in studying, mapping, and systematizing the knowledge concerning the topic of handling conflicts in VTs. Considering the current contingencies this research is particularly timely

    Reasserting Arts Education in K-12 Curriculum: A Qualitative Case Study and Pilot Programs

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    From September 2015 through September 2017, the Ruth and Elmer Wellin Museum of Art at Hamilton College conducted a cross-sectional study that asked, “What makes K-12 public school educators choose to use a museum as part of their curriculum?” At the time of this research, no qualitative studies—either regional or national—could be found on this subject. Studies addressing the “how” and the “what” involved in museum-school collaborations had been published, but none looked at the “why” that motivated such partnerships. This mixed-method, regional study reflects perspectives of teachers and administrators on the museum-school collaboration dynamic after the introduction of the Common Core State Standards Initiative. It employed focus groups, online questionnaires, and personal interviews of 140 teachers and administrators working in Oneida, Herkimer, and Madison counties in New York State. Additionally, four peer academic museums were interviewed to determine best practices in the field of museum education in relation to the research topic. Two pilot programs were implemented at the Wellin Museum in response to the first year of data findings. Ninety-five percent of respondents reported finding value in using a museum as part of their curriculum, yet 41% had never done so. Issues of time, cost, and defensibility were widely reported by teachers as detractors to museum-school collaborations. Administrators suggested programming that could be embedded in the curriculum, creating lasting partnerships that could be budgeted for and pre-scheduled annually. Professional development offerings, accommodation of large groups for tours, and in-school programming were also reportedly important to administrators. The study determined that although the tenets of the Common Core curriculum necessary for successful museum-school collaborations are being offered readily by museums, that fact may not always be communicated clearly to K-12 educators. By using terminology that teachers and administrators recognize, museums can increase the ease of use and defensibility of their programming, thus increasing museum-school collaborations.https://digitalcommons.hamilton.edu/books/1027/thumbnail.jp

    Оптимизация мощности и задержки наноразмерного (4х1)-мультиплексора при использовании схемы удвоителя напряжения на КМОП структурах

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    Полный текст доступен на сайте издания по подписке: http://radio.kpi.ua/article/view/S0021347016110017Работа поддержана университетом ITM (Гвалиор) и компанией Cadence System Design (Бангалор)В статье представлен высокоэффективный (4×1)-мультиплексор с малой утечкой и уменьшенной задержкой, снабженный схемой удвоителя напряжения на МОП-структурах, которая совмещена с расширенной МОП-конфигурацией транзисторов ждущего режима наноразмерной структуры. Оригинальная конструкция схемы удвоителя напряжения реализована в виде дополнительной схемы на выходе предложенной конструкции для ступенчатого увеличения напряжения. Это позволило удвоить выходное пиковое напряжение за счет переходных процессов положительного и отрицательного циклов. Это повышенное напряжение может использоваться в качестве стабилизированного источника питания для определенных целей. Наличие схемы удвоителя напряжения не является достаточным для улучшения общей эффективности предложенной конструкции (4×1)-мультиплексора. Для получения одновременной оптимизации по мощности рассеяния (мощность утечки) и длительности задержки схема удвоителя напряжения используется совместно с расширенной МОП-конфигурацией транзисторов ждущего режима. Для минимизации параметра мощности рассеяния, вызванной утечкой, введена схема удвоителя напряжения на МОП-структурах, совмещенная с расширенной конфигурацией транзисторов ждущего режима. Это позволило уменьшить избыточную мощность рассеяния схемы, обусловленную утечкой. Указанная дополнительная часть схемы позволяет получить необходимый уровень выходного напряжения у предложенного (4×1)-мультиплексора при улучшенных параметрах. Моделирование устройства осуществлялось при использовании технологии 45 нм. В результате мощность рассеяния, обусловленная утечкой, уменьшена до уровня примерно 55%, а характеристика задержки улучшена до требуемого уровня благодаря использованию схемы удвоителя напряжения на МОП-структурах совместно с улучшенной МОП-конфигурацией транзисторов ждущего режима. В статье представлены различные комбинации схемы удвоителя напряжения на МОП-структурах, реализованные на выходе (4×1)-мультиплексора

    Recombination in Streptococcus pneumoniae Lineages Increase with Carriage Duration and Size of the Polysaccharide Capsule.

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    Streptococcus pneumoniae causes a high burden of invasive pneumococcal disease (IPD) globally, especially in children from resource-poor settings. Like many bacteria, the pneumococcus can import DNA from other strains or even species by transformation and homologous recombination, which has allowed the pneumococcus to evade clinical interventions such as antibiotics and pneumococcal conjugate vaccines (PCVs). Pneumococci are enclosed in a complex polysaccharide capsule that determines the serotype; the capsule varies in size and is associated with properties including carriage prevalence and virulence. We determined and quantified the association between capsule and recombination events using genomic data from a diverse collection of serotypes sampled in Malawi. We determined both the amount of variation introduced by recombination relative to mutation (the relative rate) and how many individual recombination events occur per isolate (the frequency). Using univariate analyses, we found an association between both recombination measures and multiple factors associated with the capsule, including duration and prevalence of carriage. Because many capsular factors are correlated, we used multivariate analysis to correct for collinearity. Capsule size and carriage duration remained positively associated with recombination, although with a reduced P value, and this effect may be mediated through some unassayed additional property associated with larger capsules. This work describes an important impact of serotype on recombination that has been previously overlooked. While the details of how this effect is achieved remain to be determined, it may have important consequences for the serotype-specific response to vaccines and other interventions. IMPORTANCE: The capsule determines >90 different pneumococcal serotypes, which vary in capsule size, virulence, duration, and prevalence of carriage. Current serotype-specific vaccines elicit anticapsule antibodies. Pneumococcus can take up exogenous DNA by transformation and insert it into its chromosome by homologous recombination. This mechanism has disseminated drug resistance and generated vaccine escape variants. It is hence crucial to pneumococcal evolutionary response to interventions, but there has been no systematic study quantifying whether serotypes vary in recombination and whether this is associated with serotype-specific properties such as capsule size or carriage duration. Larger capsules could physically inhibit DNA uptake, or given the longer carriage duration for larger capsules, this may promote recombination. We find that recombination varies among capsules and is associated with capsule size, carriage duration, and carriage prevalence and negatively associated with invasiveness. The consequence of this work is that serotypes with different capsules may respond differently to selective pressures like vaccines

    Synthesis of Control System in E-navigation

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    Učestali problem u pomorskom prometu jest smanjenje sigurnosti odvijanja plovidbe. Prisutno je više čimbenika koji u određenoj mjeri utječu na sigurnost broda, ljudi i imovine te na zaštitu okoliša. Kao posljedica djelovanja pojedinih čimbenika pojavljuju se opasne situacije poput nasukanja, sudara, požara, prevrnuća, kvarova glavnog stroja, oštećenja glavnog trupa broda, onečišćenja i druge situacije. Slijedom prepoznatoga, u ovome doktorskom radu istražuju se pojavne situacije sudara i mogućnost unaprjeđenja sigurnosti plovidbe primjenom odgovarajuće metode i programskih alata. Navedena problematika u skladu je sa zahtjevima i preporukama Međunarodne pomorske organizacije (engl. International Maritime Organization - IMO) za implementacijom suvremenih sustava kao što je sustav e-navigacije u pomorstvu s ciljem unaprijeđenog korištenja i usklađivanja navigacijskih sustava. Nedostatci postojećih sustava i primijenjenih tehnologija u pomorskom prometu dolaze do izražaja posebno u čvorištima morskih prolaza gdje je prisutno smanjenje širine prolaza i povećanje gustoće prometa. Cilj doktorskoga rada jest razviti formalnu metodu za sintezu nadzornog sustava upravljanja pomorskim prometom u akvatorijima povećane sudarne opasnosti koji bi pratio pomorski promet i njime upravljao te ograničavao prijelaz brodova između pojedinih sektora. Sustav ranog upozorenja na moguće opasnosti, praćenjem rute koju brod dobiva od obalnog centra za slučaj da brod ne slijedi unaprijed predefiniranu rutu, izdaje upozorenje operateru u nadzornom centru i na brodu. Predloženi nadzorni sustav ograničava kretanje brodova između sektora kao najmanje prostorne jedinice u kojoj se nalazi jedan brod te koordinira prometom brodova u čvorištima samo u slučaju povećane sudarne opasnosti. U doktorskome radu je sintetiziran nadzorni sustav koji upravlja pomorskim prometom korištenjem Petrijevih mreža i matematičke metode P-invarijante, a verifikacija nadzornog sustava provodi se računalnom simulacijom primjenom programa Visual Object Net.A common problem in maritime transport is safety. More factors affect the safety of the ship, the people, the environment and property. These factors are the grounding, collision, fire, capsizing, failure of the main electricity, damage to the main hull, pollution and so on. The factor that is considered in this thesis are collisions which are considered respectively through this doctoral thesis on the real problems of maritime transport using appropriate software tools to improve safety navigation. International Maritime Organization - IMO seeks to implement new systems such as e-Navigation in shipping with a view to harmonize the use of advanced navigation systems . Disadvantages of such systems and technologies are reflected in the traffic crossing of sea passages where the passage width decreases and the traffic density increases. The goal of this doctoral thesis is to develop formal method for sinthesis of supervising system for controlling marine traffic in aquatoria with increased collision danger which would monitor and control marine traffic and restrict transition of ships between the sectors. The objective of installing a supervising system in the coastal center is to prevent collisions and to improve safety in dangerous sea passages. The supervising system would monitor the traffic of ships in the respective traffic crossing in a way to achieve an early warning of impending danger. The supervising system would track the route that ship receives from the coastal center, and in the event that the ship does not follow a fixed route, supervising system alerts operators at traffic control center and ship. The proposed supervising system would restrict moving of ships between sectors and coordinate the traffic of ships traffic crossing only in the event of high collision risk. This paper synthesizes the supervising system which controls the vessel traffic using Petri net and the P-invariant mathematical method. Verification of the supervising system is done by using computer simulations based on Petri net program ''Visual Object Net''

    Synthesis of Control System in E-navigation

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    Učestali problem u pomorskom prometu jest smanjenje sigurnosti odvijanja plovidbe. Prisutno je više čimbenika koji u određenoj mjeri utječu na sigurnost broda, ljudi i imovine te na zaštitu okoliša. Kao posljedica djelovanja pojedinih čimbenika pojavljuju se opasne situacije poput nasukanja, sudara, požara, prevrnuća, kvarova glavnog stroja, oštećenja glavnog trupa broda, onečišćenja i druge situacije. Slijedom prepoznatoga, u ovome doktorskom radu istražuju se pojavne situacije sudara i mogućnost unaprjeđenja sigurnosti plovidbe primjenom odgovarajuće metode i programskih alata. Navedena problematika u skladu je sa zahtjevima i preporukama Međunarodne pomorske organizacije (engl. International Maritime Organization - IMO) za implementacijom suvremenih sustava kao što je sustav e-navigacije u pomorstvu s ciljem unaprijeđenog korištenja i usklađivanja navigacijskih sustava. Nedostatci postojećih sustava i primijenjenih tehnologija u pomorskom prometu dolaze do izražaja posebno u čvorištima morskih prolaza gdje je prisutno smanjenje širine prolaza i povećanje gustoće prometa. Cilj doktorskoga rada jest razviti formalnu metodu za sintezu nadzornog sustava upravljanja pomorskim prometom u akvatorijima povećane sudarne opasnosti koji bi pratio pomorski promet i njime upravljao te ograničavao prijelaz brodova između pojedinih sektora. Sustav ranog upozorenja na moguće opasnosti, praćenjem rute koju brod dobiva od obalnog centra za slučaj da brod ne slijedi unaprijed predefiniranu rutu, izdaje upozorenje operateru u nadzornom centru i na brodu. Predloženi nadzorni sustav ograničava kretanje brodova između sektora kao najmanje prostorne jedinice u kojoj se nalazi jedan brod te koordinira prometom brodova u čvorištima samo u slučaju povećane sudarne opasnosti. U doktorskome radu je sintetiziran nadzorni sustav koji upravlja pomorskim prometom korištenjem Petrijevih mreža i matematičke metode P-invarijante, a verifikacija nadzornog sustava provodi se računalnom simulacijom primjenom programa Visual Object Net.A common problem in maritime transport is safety. More factors affect the safety of the ship, the people, the environment and property. These factors are the grounding, collision, fire, capsizing, failure of the main electricity, damage to the main hull, pollution and so on. The factor that is considered in this thesis are collisions which are considered respectively through this doctoral thesis on the real problems of maritime transport using appropriate software tools to improve safety navigation. International Maritime Organization - IMO seeks to implement new systems such as e-Navigation in shipping with a view to harmonize the use of advanced navigation systems . Disadvantages of such systems and technologies are reflected in the traffic crossing of sea passages where the passage width decreases and the traffic density increases. The goal of this doctoral thesis is to develop formal method for sinthesis of supervising system for controlling marine traffic in aquatoria with increased collision danger which would monitor and control marine traffic and restrict transition of ships between the sectors. The objective of installing a supervising system in the coastal center is to prevent collisions and to improve safety in dangerous sea passages. The supervising system would monitor the traffic of ships in the respective traffic crossing in a way to achieve an early warning of impending danger. The supervising system would track the route that ship receives from the coastal center, and in the event that the ship does not follow a fixed route, supervising system alerts operators at traffic control center and ship. The proposed supervising system would restrict moving of ships between sectors and coordinate the traffic of ships traffic crossing only in the event of high collision risk. This paper synthesizes the supervising system which controls the vessel traffic using Petri net and the P-invariant mathematical method. Verification of the supervising system is done by using computer simulations based on Petri net program ''Visual Object Net''
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