76 research outputs found

    A Reliable Communication Model Based on IEEE802.15.4 for WSANs in Smart Grids

    Get PDF
    Creating cyber-physical systems (CPSs) based on wireless sensor and actuator networks (WSANs) has great potential to improve the performance of Smart Grid. In addition, IEEE802.15.4 has widely been regarded as an appropriate standard for WSANs, due to some striking and unique features. WSANs require provisioning strict quality of service (QoS) due to noisy harsh environments in Smart Grid applications. Although analytical models have been studied in the literature, they have not provided a full-fledged model for Smart Grid. In this paper, we have added a MAC-level buffer, and a novel Markov chain model has been also proposed. By comparison with previous studies, retransmission confines, acknowledgment, packet length variation, saturated traffic, and degenerate distribution of packet generation are accounted for. The algorithm has been experimentally implemented and appraised on a platform with self-designed WSAN. The analytical model predicts well our exhaustive experiments. Further, Monte Carlo simulations validate mathematical results

    VISION INSPECTION AND MONITORING OF WIND TURBINE FARMS IN EMERGING SMART GRIDS

    Get PDF
    Todays, Smart Grids as the goal of next generation power grid system span wide and new aspects of power generation from distributed and bulk power generators to the end-user utilities. There are many advantages to develop these complex and multilayer system of systems such as increasing agility, reliability, efficiency, privacy, security for both Energy and ICT sections in smart grid architecture. In emerging smart grids, the communication infrastructures play main role in grid development and as a result multimedia applications are more practical for the future power systems. In this work, we introduce our method for monitoring and inspection of Wind Turbine (WT) farms in smart grids. In our proposed system, a thermal vision camera is embedded on a wireless sensor node for each WT to capture appropriate images and send video streams to the coordinator. It gets video frames to perform machine Vision Inspection (VI) and monitoring purposes. In our constructed model, turbine blade velocity estimation is targeted by detecting two important landmarks in the image that are named hub and blade. By tracking the blade in the consecutive frames and based on proposed scoring function, we can estimate the velocity of the turbine blade. Obtained results clearly indicate that accurate hub and blade positions extraction lead to error free estimation of turbine blade velocity

    Intelligent adaptive multi-parameter migration model for load balancing virtualized cluster of servers

    Get PDF
    Najvažnija korist virtualizacije je dobivanje okruženja s ujednačenim opterećenjem kroz prenošenje (migraciju) virtualnim strojem (VM). Djelovanje usluga u skupinama (klasterima), kao što je prosječno vrijeme reakcije - Average Response Time - reducirano je inteligentnom odlukom VM o prenošenju. Prenošenje ovisi o nizu kriterija poput korištenja resursa (uporaba CPU, korištenje RAMa, korištenje mreže, itd.) i potrebe za strojevima (fizičkim (PM) i virtualnim (VM)). To je više- kriterijski problem prenošenja koji procjenjuje, komparira i sortira niz fizičkih i virtualnih strojeva (PM i VM) na osnovu parametara istaknutih u procesu prenošenja. Ali, koji parametar (parametri) ima dominantnu ulogu nad djelovanjem klastera u određenom vremenskom odjeljku? Kako možemo odrediti težinu parametara u nadolazećim vremenskim razmacima? Postojeći algoritmi prenošenja (migration algorithms) ne uzimaju u obzir težine parametara koje se mijenjaju ovisno o vremenu. Te analize pretpostavljaju fiksnu težinu za svaki parametar kroz široki raspon vremenskih intervala. To dovodi do netočnog predviđanja o traženju rješenja za svaki server. U našem se radu predstavlja novi Inteligentni i Adaptivni Multi Parametarski (IAMP) upravljač resursima na bazi prenošenja (migracije) za virtualizirane centre podataka i klastere s novom na umjetnoj neuronskoj mreži (ANN) temeljenoj analizi težina nazvanoj Error Number of Parameter Omission (ENPO). U svakom se vremenskom razmaku težina parametara ponovo izračunava te će nevažni parametri biti oslabljeni u postupku rangiranja. Obilježili smo parametre koji utječu na performansu klastera i koristili hot migration s naglaskom na skupini servera u XEN platformi virtualizacije. Eksperimentalni rezultati temeljeni na radnim opterećenjima sastavljenim od stvarnih aplikacija pokazuju da je primjenom IAMP-a moguće poboljšati rad virtualnog klaster sustava do 23 % u usporedbi s postojećim algoritmima. Što više, on brže reagira i eliminira vruće točke zbog svog potpuno dinamičkog upravljačkog algoritma.The most important benefit of virtualization is to get a load balanced environment through Virtual Machine (VM) migration. Performance of clustered services such as Average Response Time is reduced through intelligent VM migration decision. Migration depends on a variety of criteria like resource usage (CPU usage, RAM usage, Network Usage, etc.) and demand of machines (Physical (PM) and Virtual (VM)). This is a multi-criteria migration problem that evaluates, compares and sorts a set of PMs and VMs on the basis of parameters affected on migration process. But, which parameter(s) has dominant role over cluster performance in each time window? How can we determine weight of parameters over oncoming time slots? Current migration algorithms do not consider time-dependent variable weights of parameters. These studies assume fixed weight for each parameter over a wide range of time intervals. This approach leads to imprecise prediction of recourse demand of each server. Our paper presents a new Intelligent and Adaptive Multi Parameter migration-based resource manager (IAMP) for virtualized data centres and clusters with a novel Artificial Neural Network (ANN)-based weighting analysis named Error Number of Parameter Omission (ENPO). In each time slot, weight of parameters is recalculated and non-important ones will be attenuated in ranking process. We characterized the parameters affecting cluster performance and used hot migration with emphasis on cluster of servers in XEN virtualization platform. The experimental results based on workloads composed of real applications, indicate that IAMP management framework is feasible to improve the performance of the virtualized cluster system up to 23 % compared to current algorithms. Moreover, it reacts more quickly and eliminates hot spots because of its full dynamic monitoring algorithm

    Effects of Echinacea purpurea Extract on Sperm Characteristics and Hematology Following Testicular Ischemia-Reperfusion Injury in Rat

    Get PDF
    Objectives: The aim of the present study was to investigate the effects of Echinacea purpurea extract on sperm characteristics following testicular ischemia/reperfusion (I/R) injury in rats. Materials and Methods: To evaluate this hypothesis, 30 adult rats were randomly divided into 5 groups: sham operations, I/R group and 3 groups of treatment with E. purpurea extract (25, 50 and 100 mg/kg). To achieve testicular I/R, torsion (720°) of spermatic cord for 2 hours and reperfusion of the tests for 24 hours were performed. Treatment was done by intraperitoneal injection of 3 different doses of E. purpurea extract, 1 hour after ischemia. Then, the sperm count, motility and mobility were determined. Results: There was a significant increase in sperm count, motility and mobility in treatment groups compared to I/R group (P<0.05). Treatment with E. purpurea extract (25, 50 and 100 mg/kg) significantly attenuated the adverse effect of testicular I/R on sperm mortality compared to the control group (P < 0.05). No significant difference was observed in hemograms. Conclusions: These results confirmed beneficial effects of E. purpurea extract on sperm characteristics after testicular I/R injury in rats

    Perturbation Analysis of Heterochromatin-Mediated Gene Silencing and Somatic Inheritance

    Get PDF
    Repetitive sequences in eukaryotic genomes induce chromatin-mediated gene-silencing of juxtaposed genes. Many components that promote or antagonize silencing have been identified, but how heterochromatin causes variegated and heritable changes in gene expression remains mysterious. We have used inducible mis-expression in the Drosophila eye to recover new factors that alter silencing caused by the bwD allele, an insertion of repetitive satellite DNA that silences a bw+ allele on the homologous chromosome. Inducible modifiers allow perturbation of silencing at different times in development, and distinguish factors that affect establishment or maintenance of silencing. We find that diverse chromatin and RNA processing factors can de-repress silencing. Most factors are effective even in differentiated cells, implying that silent chromatin remains plastic. However, over-expression of the bantam microRNA or the crooked-legs (crol) zinc-finger protein only de-repress silencing when expressed in cycling cells. Over-expression of crol accelerates the cell cycle, and this is required for de-repression of silencing. Strikingly, continual over-expression of crol converts the speckled variegation pattern of bwD into sectored variegation, where de-repression is stably inherited through mitotic divisions. Over-expression of crol establishes an open chromatin state, but the factor is not needed to maintain this state. Our analysis reveals that active chromatin states can be efficiently inherited through cell divisions, with implications for the stable maintenance of gene expression patterns through development

    In Vitro Aggregation Behavior of a Non-Amyloidogenic λ Light Chain Dimer Deriving from U266 Multiple Myeloma Cells

    Get PDF
    Excessive production of monoclonal light chains due to multiple myeloma can induce aggregation-related disorders, such as light chain amyloidosis (AL) and light chain deposition diseases (LCDD). In this work, we produce a non-amyloidogenic IgE λ light chain dimer from human mammalian cells U266, which originated from a patient suffering from multiple myeloma, and we investigate the effect of several physicochemical parameters on the in vitro stability of this protein. The dimer is stable in physiological conditions and aggregation is observed only when strong denaturating conditions are applied (acidic pH with salt at large concentration or heating at melting temperature Tm at pH 7.4). The produced aggregates are spherical, amorphous oligomers. Despite the larger β-sheet content of such oligomers with respect to the native state, they do not bind Congo Red or ThT. The impossibility to obtain fibrils from the light chain dimer suggests that the occurrence of amyloidosis in patients requires the presence of the light chain fragment in the monomer form, while dimer can form only amorphous oligomers or amorphous deposits. No aggregation is observed after denaturant addition at pH 7.4 or at pH 2.0 with low salt concentration, indicating that not a generic unfolding but specific conformational changes are necessary to trigger aggregation. A specific anion effect in increasing the aggregation rate at pH 2.0 is observed according to the following order: SO4−≫Cl−>H2PO4−, confirming the peculiar role of sulfate in promoting protein aggregation. It is found that, at least for the investigated case, the mechanism of the sulfate effect is related to protein secondary structure changes induced by anion binding

    Nanotechnology in peripheral nerve repair and reconstruction

    Get PDF
    The recent progress in biomaterials science and development of tubular conduits (TCs) still fails in solving the current challenges in the treatment of peripheral nerve injuries (PNIs), in particular when disease-related and long-gap defects need to be addressed. Nanotechnology-based therapies that seemed unreachable in the past are now being considered for the repair and reconstruction of PNIs, having the power to deliver bioactive molecules in a controlled manner, to tune cellular behavior, and ultimately guide tissue regeneration in an effective manner. It also offers opportunities in the imaging field, with a degree of precision never achieved before, which is useful for diagnosis, surgery and in the patientâ s follow-up. Nanotechnology approaches applied in PNI regeneration and theranostics, emphasizing the ones that are moving from the lab bench to the clinics, are herein overviewed.The authors acknowledge the Portuguese Foundation for Science and Technology (FCT) for the financial support provided to Joaquim M. Oliveira (IF/01285/2015) and Joana Silva-Correia (IF/00115/2015) under the program “Investigador FCT”.info:eu-repo/semantics/publishedVersio
    corecore