Context Light weight process virtualization has been used in the past e.g., Solaris zones, jails in Free BSD and Linux’s containers (LXC). But only since 2013 is there a kernel support for user namespace and process grouping control that make the use of lightweight virtualization interesting to create virtual environments comparable to virtual machines. Telecom providers have to handle the massive growth of information due to the growing number of customers and devices. Traditional databases are not designed to handle such massive data ballooning. NoSQL databases were developed for this purpose. Cassandra, with its high read and write throughputs, is a popular NoSQL database to handle this kind of data. Running the database using operating system virtualization or containerization would offer a significant performance gain when compared to that of virtual machines and also gives the benefits of migration, fast boot up and shut down times, lower latency and less use of physical resources of the servers. Objectives This thesis aims to investigate the trade-off in performance while loading a Cassandra cluster in bare-metal and containerized environments. A detailed study of the effect of loading the cluster in each individual node in terms of Latency, CPU and Disk throughput will be analyzed. Method We implement the physical model of the Cassandra cluster based on realistic and commonly used scenarios or database analysis for our experiment. We generate different load cases on the cluster for Bare-Metal and Docker and see the values of CPU utilization, Disk throughput and latency using standard tools like sar and iostat. Statistical analysis (Mean value analysis, higher moment analysis and confidence intervals) are done on measurements on specific interfaces in order to show the reliability of the results. Results Experimental results show a quantitative analysis of measurements consisting Latency, CPU and Disk throughput while running a Cassandra cluster in Bare Metal and Container Environments. A statistical analysis summarizing the performance of Cassandra cluster while running single Cassandra is surveyed. Conclusions With the detailed analysis, the resource utilization of the database was similar in both the bare-metal and container scenarios. From the results the CPU utilization for the bare-metal servers is equivalent in the case of mixed, read and write loads. The latency values inside the container are slightly higher for all the cases. The mean value analysis and higher moment analysis helps us in doing a finer analysis of the results. The confidence intervals calculated show that there is a lot of variation in the disk performance which might be due to compactions happening randomly. Further work can be done by configuring the compaction strategies, memory, read and write rates.

No description available.

京都大学 / 0048 / 新制・論文博士 / 博士(医学) / 乙第13207号 / 論医博第2161号 / 新制||医||1031(附属図書館) / (主査)教授 福原 俊一, 教授 湊谷 謙司, 教授 小池 薫 / 学位規則第4条第2項該当 / Doctor of Medical Science / Kyoto University / DFAM

Made available in DSpace on 2016-12-12T20:22:53Z (GMT). No. of bitstreams: 1 Mauro Hinz.pdf: 2658972 bytes, checksum: 50ee82c291499d5ddc390671e05329d4 (MD5) Previous issue date: 2015-09-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The outsourcing of computing services has been through constant evolutions in the past years, due to the increase of demand for computing resources. Accordingly, data centers are the main suppliers of computing service and cloud-based computing services provide a new paradigm for the offer and consumption of these computing resources. A substantial motivator for using cloud computing is its pricing model, which enables to charge the customer only for the resources he used, thus adopting a pay-as-you-use cost model. Among cloud-based computing services, the service type Infrastructure-as-a-Service (IaaS) is the one mostly used by companies that would like to outsource their computing infrastructure. The IaaS service, in most cases, is offered through virtual machines. This paper revisits the cost models used by data centers and analyses the costs of supply of virtual machines based on IaaS. This analysis identifies that electricity represents a considerable portion of this cost and that much of the consumption comes from the use of processors in virtual machines, and that this aspect is not considered in the identified cost models. This paper describes the Virtual Power Model, a cost model based on energy consumption of the processor in cloud-based, virtual machines in IaaS. The model is based on the assumptions of energy consumption vs. processing load, among others, which are proven through experiments in a test environment of a small data center. As a result, the Virtual Power Model proves itself as a fairer pricing model for the consumed resources than the identified models. Finally, a case study is performed to compare the costs charged to a client using the cost model of Amazon for the AWS EC2 service and the same service charged using the Virtual Power Model. / A terceirização dos serviços de computação tem passado por evoluções constantes nos últimos anos em função do contínuo aumento na demanda por recursos computacionais. Neste sentido, os data centers são os principais fornecedores de serviço de computação e os serviços de computação em nuvem proporcionam um novo paradigma na oferta e consumo desses recursos computacionais. Um considerável motivador do uso das nuvens computacionais é o seu modelo de tarifação que possibilita a cobrança do cliente somente dos recursos que ele utilizou, adotando um modelo de custo do tipo pay-as-you-use. Dentre os serviços de computação em nuvem, o serviço do tipo IaaS (Infrastructure-as-a-Service) é um dos mais utilizados por empresas que desejam terceirizar a sua infraestrutura computacional. O serviço de IaaS, na grande maioria dos casos, é ofertado através de instâncias de máquinas virtuais. O presente trabalho revisita os modelos de custos empregados em data centers analisando a formação dos custos no fornecimento de máquina virtuais em nuvens baseadas em IaaS. Com base nesta análise identificasse que a energia elétrica possui uma parcela considerável deste custo e que boa parte deste consumo é proveniente do uso de processadores pelas máquinas virtuais, e que esse aspecto não é considerado nos modelos de custos identificados. Este trabalho descreve o Modelo Virtual Power, um modelo de custo baseado no consumo de energia do processador por máquina virtual em nuvens IaaS. A constituição do modelo está baseada nas premissas de consumo de energia vs. carga de processamento, entre outros, que são comprovados através de experimentação em um ambiente de testes em um data center de pequeno porte. Como resultado o Modelo Virtual Power mostra-se mais justo na precificação dos recursos consumidos do que os modelos identificados. Por fim, é realizado um estudo de caso comparando os custos tarifado a um cliente empregando o modelo de custo da Amazon no serviço AWS EC2 e o mesmo serviço tarifado utilizando o Modelo Virtual Power.

Made available in DSpace on 2014-07-29T15:07:09Z (GMT). No. of bitstreams: 1 Dissertacao Harley Fernandes Rodrigues.pdf: 5566711 bytes, checksum: 484423a034c8d6a3a3f34650b5036af1 (MD5) Previous issue date: 2011-08-23 / In this work we developed a Dip Coating method that could control the temperature gradient between a substrate and the material that one wants to adsorb at its surface. In particular, the adsorption of biocompatible magnetic nanoparticles at the surface of bare metal Stents, under different experimental conditions, was investigated. The magnetic nanoparticles consisted of magnetite coated with tripoliphosphate (mean diameter 7.68 nm and standard deviation 1.88 nm) dispersed in water at physiological conditions, while the Stent was a CoCr based-one (Cronus stent from Scitech with 16 mm length). Nine series of experiments were performed where it was controlled parameters as: time of adsorption, stent temperature and magnetic fluid temperature. The stents coated with nanoparticles were magnetically characterized using a vibrating sample magnetometer (VSM), which allowed us to determine the number of nanoparticles at the stent surface. The increase of the magnetic moment of the stent with the increase of the adsorption time was theoretically modeled, with an excellent experimental agreement, as a transient diffusion process of nanoparticles at the interface stent-magnetic fluid, which clearly indicates an important diffusive contribution. Strong evidences of thermal diffusion (Soret effect), i.e. nanoparticle diffusion due to temperature gradient between the stent and the magnetic fluid, were shown, suggesting the possibility of nanostructures vectorization through thermal induced mechanisms. The spatial distribution of nanoparticles at the surface of the stent was investigated by Scanning Electron Microscopy (SEM) and X-ray Spectroscopy by Dispersive Energy (EDS). Measurements of the compositional mapping and images of SEM revealed that the nanoparticles are not homogeneously distributed, being concentrated at the edges of the stents for the experimental conditions investigated in this work. As the VSM data, the EDS of the stents revealed an increase of the quantity of adsorbed magnetic nanoparticles at the surface with the increase of the adsorption time. The same theoretical model, know considering the amount of 26Fe in the chemical composition of the coated stent, was able to explain the experimental data. Finally, a comparison was made, using the compositional mapping study of the coated stents, between the Dip Coating and the Spray technique. The later showed a more homogeneous distribution of nanoparticles at the surface of the stent, suggesting that this technique is more adequate on the development of a biomedical nanoproduct for clinical tests. / Neste trabalho foi desenvolvida uma técnica de Dip Coating (deposição por via líquida) que permite controlar o gradiente de temperatura entre o substrato e o material que se quer depositar em sua superfície. Em particular, foi investigado o efeito de adsorção de nanopartículas magnéticas biocompatíveis na superfície de Stents nus em diversas condições experimentais. As nanopartículas magnéticas consistiam de magnetita recobertas com tripolifosfato (diâmetro médio ) dispersas em água em pH fisiológico, enquanto as endopróteses eram Stents de CoCr (Stent Cronus da empresa Scitech com 16mm). Ao todo foram realizadas 9 séries de experimentos onde controlou-se parâmetros como: tempo de adsorção, temperatura do Stent e temperatura do fluido magnético. Os Stents recobertos com nanopartículas foram então caracterizados magneticamente pela técnica de magnetometria de amostra vibrante (VSM Vibrating Sample Magnetometer ), que permitiu determinar o número de nanopartículas magnéticas adsorvidas na superfície da endoprótese. O aumento do momento magnético do Stent com o aumento do tempo de adsorção foi modelado teoricamente, com grande concordância experimental, como um processo de difusão transiente de nanopartículas na interface Stent-fluido magnético, evidenciando a forte contribuição difusiva. Fortes evidências de efeitos termodifusivos (efeito de Soret), ou seja mecanismos de difusão mássica de nanopartículas devido ao gradiente de temperatura entre Stent e FM, foram apresentados, sugerindo a possibilidade de vetorização de nanoestruturas por meio de fenômenos termoinduzidos. A distribuição das nanopartículas na superfície dos Stents foi investigada por medidas de Microscopia Eletrônica de Varredura (MEV) e espectroscopia de raios-X por energia dispersiva (EDS). As medidas de mapeamento composicional e imagens de MEV revelaram que as nanopartículas estão distribuídas de maneira não homogênea, estando concentradas nas bordas dos Stents para as condições experimentais utilizadas neste trabalho. Assim como os dados de MAV, o EDS dos Stents recobertos revelou um aumento da quantidade de nanopartículas magnéticas adsorvidas em sua superfície com o aumento do tempo de adsorção. O mesmo modelo teórico, agora considerando o percentual de 26Fe na composição química do revestimento, foi capaz de explicar os dados experimentais. Finalmente, foi feita uma comparação, por meio do mapeamento composicional de Stents recobertos, entre as técnicas de Dip Coating e Spray. Esta última apresentou uma distribuição de nanopartículas mais homogênea na superfície da endoprótese, sugerindo que possa ser mais adequada para a confecção de um nanoproduto médico voltado a testes clínicos.

Background: Drug eluting stents (DES) are preferred over bare metal stents (BMS) for native coronary artery revascularization unless contraindicated. However, the preferred stent choice for saphenous venous graft (SVG) percutaneous coronary interventions (PCI) is unclear due to conflicting results. Methods: PubMed, Clinical trials registry and the Cochrane Center Register of Controlled Trials were searched through June 2018. Seven studies (n = 1639) comparing DES versus BMS in SVG-PCI were included. Endpoints were major adverse cardiac events (MACE), cardiovascular mortality, all-cause mortality, myocardial infarction (MI), target vessel revascularization (TVR), target lesion revascularization (TLR), in-stent thrombosis, binary in-stent restenosis, and late lumen loss (LLL). Results: Overall, during a mean follow up of 32.1 months, there was no significant difference in the risk of MACE, cardiovascular mortality, all-cause mortality, MI, stent thrombosis, TVR and TLR between DES and BMS. However, short-term follow up (mean 11 months) showed lower rate of MACE (OR 0.66 [0.51, 0.85]; p = 0.002), TVR (OR 0.47 [0.23, 0.97]; p = 0.04) and binary in-stent restenosis (OR 0.14 [0.06, 0.37]; p < 0.0001) in DES as compared with BMS. This benefit was lost on long-term follow up with a mean follow up 35.5 months. Conclusion: In this meta-analysis of SVG-PCI, DES use was associated with similar MACE, cardiovascular mortality, all-cause mortality, MI, in-stent thrombosis, TVR and TLR compared with BMS during long-term follow up. There was high incidence of MACE noted in both DES and BMS suggesting a need for exploring novel strategies to treat SVG disease to improve clinical outcomes.

In recent years, developers have wanted to design more complex and advanced embedded processors. The feasibility of developed processors must be verified before the actual application. However, the process of verification always needs high costs and time. Quick Emulator (QEMU), a virtual platform emulator, can help in this situation. It can emulate different processors and hardware environments and build a unique platform according to the designers wishes. Many people have used QEMU to emulate advanced Reduced Instruction Set Computing (RISC) processors (like ARM) or the X86 architectures. Still, there is little research on RISC-V processors. Therefore, studying the QEMU to emulate the RISC-V processor is important. This thesis aims to evaluate the performance of the RISC-V processor using QEMU. Ten different benchmarks are designed, and their results are compared to reflect the performance of the RISC-V as well as the simulator. These results provide a reference when these benchmarks are run on the RISC-V processor that is on the actual hardware development board. / De senaste åren har utvecklarna alltid velat utveckla mer komplexa och avancerade funktioner på inbyggda utvecklingskort. Men de nya funktionerna måste verifieras innan man gör kretskortet. Å andra sidan så kostar verifieringsprocessen mycket tid och pengar. Quick Emulator (QEMU), en virtuell plattformsemulator, kan hjälpa till för att lösa detta problem. Den kan emulera olika processorer och hårdvarumiljöer och bygga en unik plattform allt enligt designernas önskemål. Många människor har använt QEMU för att emulera avancerade Reduced Instruction Set Computing (RISC)-processorer (som ARM), eller X86-arkitekturerna, men det finns mycket lite forskning om RISC-V processorer. Därför är det viktigt att studera QEMU för att emulera RISC-V-processorn. Denna avhandling syftar till att utvärdera prestandan för RISC-V processorer genom att använder QEMU. Tio olika benchmarks konstrueras för att användas för att spegla prestandan hos processorn såväl som simulatorn. Dessa resultat kan sedan användas som referens när benchmarken körs på de RISC-V-processorer som finns på det aktuella hårdvaruutvecklingskortet.

The Internet of Things is deploying large numbers of bare-metal systems that have no protection against memory corruption and control-flow hijacking attacks. These attacks have enabled unauthorized entry to hotel rooms, malicious control of unmanned aerial vehicles, and invasions of privacy. Using static and dynamic analysis these systems can utilize state-of-the-art testing techniques to identify and<br>prevent memory-corruption errors and employ defenses against memory corruption and control-flow hijacking attacks in bare-metal systems that match or exceed those currently employed on desktop systems. This is shown using three case studies.<br><br>(1) EPOXY which, automatically applies data execution prevention, diversity, stack defenses, and separating privileged code from unprivileged code using a novel<br>technique called privileged overlaying. These protections prevent code injection attacks, and reduce the number of privileged instruction to 0.06% verses an unprotected<br>application.<br><br>(2) Automatic Compartments for Embedded Systems (ACES), which automatically creates compartments that enforce data integrity and code isolation within bare-metal applications. ACES enables exploring policies to best meet security and performance requirements for individual applications. Results show ACES' can form 10s of compartments within a single thread and has a 15% runtime overhead on average.<br><br><div>(3) HALucinator breaks the requirement for specialized hardware to perform bare-metal system testing. This enables state-of-the-art testing techniques –e.g., coverage based fuzzing – to scale with the availability of commodity computers, leading to the discovery of exploitable vulnerabilities in bare-metal systems. <br></div><div><br></div><div>Combined, these case studies advance the security of embedded system several decades and provide essential protections for today’s connected devices.</div>

A complexidade dos sistemas integrados em chips bem como a arquitetura de processadores comerciais vem crescendo dramaticamente nos últimos anos. Com isto, a dificuldade de avaliarmos a suscetibilidade às falhas em decorrência da incidência de partículas espaciais carregadas nestes dispositivos cresce com a mesma taxa. Este trabalho apresenta uma análise comparativa da susceptibilidade à erros de software em um microprocessador embarcado ARM Cortex-A9 single core de larga escala comercial, amplamente utilizado em aplicações críticas, executando um conjunto de 11 aplicações desenvolvidas para um ambiente bare metal e para o sistema operacional Linux. A análise de soft errors é executada por injeção de falhas na plataforma de simulação OVPSim juntamente com o injetor OVPSim-FIM, capaz de sortear o momento e local de injeção de uma falha. A campanha de injeção de falhas reproduz milhares de bit-flips no banco de registradores do microprocessador durante a execução do conjunto de benchmarks que possuem um comportamento de código diverso, desde dependência de fluxo de controle até aplicações intensivas em dados. O método de análise consiste em comparar execuções da aplicação onde falhas foram injetadas com uma execução livre de falhas. Os resultados apresentam a taxa de falhas que são classificadas em: mascaradas (UNACE), travamento ou perda de controle de fluxo (HANG) e erro nos resultados (SDC). Adicionalmente, os erros são classificados por registradores, separando erros latentes por sua localização nos resultados e por exceções detectadas pelo sistema operacional, provendo novas possibilidades de análise para um processador desta escala. O método proposto e os resultados obtidos podem ajudar a orientar desenvolvedores de software na escolha de diferentes arquiteturas de código, a fim de aprimorar a tolerância à falhas do sistema embarcado como um todo. / The complexity of integrated system on-chips as well as commercial processor’s architecture has increased dramatically in recent years. Thus, the effort for assessing the susceptibility to faults due to the incidence of spatial charged particles in these devices has growth at the same rate. This work presents a comparative analysis of soft errors susceptibility in the commercial large-scale embedded microprocessor ARM Cortex-A9 single core, widely used in critical applications, performing a set of 11 applications developed for a bare metal environment and the Linux operating system. The soft errors analysis is performed by fault injection in OVPSim simulation platform along with the OVPSim-FIM fault injector, able to randomly select the time and place to inject the fault. The fault injection campaign reproduces thousands of bit-flips in the microprocessor register file during the execution of the benchmarks set, with a diverse code behavior ranging from control flow dependency to data intensive applications. The analysis method is based on comparing applications executions where faults were injected with a fault-free implementation. The results show the error rate classified by their effect as: masked (UNACE), crash or loss of control flow (HANG) and silent data corruption (SDC); and by register locations. By separating latent errors by its location in the results and exceptions detected by the operating system, one can provide new better observability for a large-scale processor. The proposed method and the results can guide software developers in choosing different code architectures in order to improve the fault tolerance of the embedded system as a whole.

Die Implantation von Atemwegstents stellt eine therapeutische Option zur Behandlung maligner und benigner Stenosierungen des Tracheobronchialsystems dar. Es handelt sich um ein effektives Verfahren das in spezialisierten Zentren und nach strenger Indikationsstellung durchgeführt werden sollte. Die Bildung von Granulationsgewebe stellt dabei eine der häufigsten Komplikationen dar. In der vorliegenden Arbeit wurden ballonexpandierbare bare-metal stents (BMS) und drug-eluting stents (DES) histologisch und immunhistochemisch untersucht.  Die zellulären und extrazellulären Gewebereaktionen der zentralen Atemwege wurde in New Zealand White Rabbits (3,1 kg bis 4,8 kg) nach Explantation von sieben bare-metal stents (Bx Sonic, Johnson & Johnson Cordis, USA) und vier Sirolimus-eluting stents (Cypher Select, Johnson & Johnson Cordis, USA) untersucht. Die Implantationszeit betrug 12 Monate. Die Implantation  metallischer Stents in die zentralen Atemwege verursachte ähnliche Gewebereaktionen wie nach koronarer Stentimplantation. Die Entzündungsreaktionen waren vergleichsweise stärker ausgeprägt. Nach 12 Monaten konnte bei beiden Stenttypen neugebildetes Gewebe auf der luminalen Seite der Implantate gesehen werden. Dieses war durchsetzt von Entzündungszellen, fibromuskulären Zellen, Kollagenfasern, elastischen Fasern und neu gebildeten Kapillaren. In zwei Stentpräparaten konnten Chondrozyten im neugebildeten Gewebe gesehen werden. Fibromuskuläre Zellen färbten positiv für Smooth Muscle Actin  und Vimentin. Vereinzelt wurde dieses Granulationsgewebe von mehrschichtigem Epithel mit kubisch-polygonalen Zellen, entsprechend einer Epithelmetaplasie, bedeckt. Nicht in die Bronchialwand eingewachsene Stentstreben wurden von Mukus, Granulozyten, Makrophagen und azellulärem Detritus bedeckt. Das Flimmerepithel zeigte sich im gestenteten Bereich deutlich reduziert. Beide Stenttypen zeigten eine vergleichbare Entzündungsreaktion. Granulozyten als Zeichen einer akuten Entzündungsreaktion konnten im neugebildetem Gewebe und an der direkten Stentoberfläche gesehen werden. Weiterhin umgaben Makrophagen und fibromuskuläre Zellen eingewachsene Stentstreben, Lymphozyten und Makrophagen schlossen sich in der unmittelbaren Umgebung an. Einige Lymphozyten wurden als B-Lymphozyten (CD79 +) identifiziert. Fremdkörperriesenzellen wurden in drei Sirolimus-freisetzenden Stentpräparaten und einem bare-metal Stentpräparat gesehen.