DOH: A Content Delivery Peer-to-Peer Network

Many SMEs and non-pro¯t organizations su®er when their Web servers become unavailable due to °ash crowd e®ects when their web site becomes popular. One of the solutions to the °ash-crowd problem is to place the web site on a scalable CDN (Content Delivery Network) that replicates the content and distributes the load in order to improve its response time. In this paper, we present our approach to building a scalable Web Hosting environment as a CDN on top of a structured peer-to-peer system of collaborative web-servers integrated to share the load and to improve the overall system performance, scalability, availability and robustness. Unlike clusterbased solutions, it can run on heterogeneous hardware, over geographically dispersed areas. To validate and evaluate our approach, we have developed a system prototype called DOH (DKS Organized Hosting) that is a CDN implemented on top of the DKS (Distributed K-nary Search) structured P2P system with DHT (Distributed Hash table) functionality [9]. The prototype is implemented in Java, using the DKS middleware, the Jetty web-server, and a modi¯ed JavaFTP server. The proposed design of CDN has been evaluated by simulation and by evaluation experiments on the prototype

Elements for Response Time Statistics in ERP Transaction Systems

We present some measurements and ideas for response time statistics in ERP systems. It is shown that the response time distribution of a given transaction in a given system is generically a log-normal distribution or, in some situations, a sum of two or more log-normal distributions. We present some arguments for this form of the distribution based on heuristic rules for response times, and we show data from performance measurements in actual systems to support the log-normal form. Deviations of the log-normal form can often be traced back to performance problems in the system. Consequences for the interpretation of response time data and for service level agreements are discussed.Comment: revtex, twocolumn, 8 pages, 13 figures. figures replaced by coloured version

Информационные технологии в банковской системе

Almost all activities of the Bank subject to the domination systems. The system itself involves a procedure control, a set of interconnected elements, procedures, methods, and many similar concepts. When the Bank is recruiting employees, it applies to this particular system, which involves placing ads on job interviews, the definition of appropriate skills, discussion of working conditions and so on. This process is a slender organized system with its internal procedures and prescribed norms

Прибор для измерения параметров магнитопровода бетатрона

В данной выпускной квалификационной работе рассмотрен способ контроля параметров центральных вкладышей малогабаритного бетатрона. На основании теоретических данных и экспериментально полученных зависимостей был разработан прибор, позволяющий оценивать качество изготовления центральных вкладышей магнитопроводящей системы бетатрона. В основе принципа работы прибора лежит способ определение добротности колебательного контура по скорости затухания его электрических колебаний.The method of controlling the parameters of the central inserts block of a betatron was considered in this final qualifying work. The device, which can measure the quality of manufacturing of central inserts block of the magnetic system of the betatron, was developed on the basis of theoretical data and experimentally obtained dependences. The principle of operation of the device is based on the method for determining the quality factor of an oscillating circuit in terms of the rate of damping of its electric oscillations

Agricultura y cambio climático: principales hallazgos y propuestas para la toma de decisiones en dos regiones naturales del Perú

Fenómenos meteorológicos extremos vinculados al cambio climático vienen afectando la productividad de cultivos que son la principal fuente de alimentación a nivel nacional, como papa, trigo, cebada, habas y maíz. Sumado a ello, la ausencia de programas integrales de extensión agrícola y asistencia técnica limita el desarrollo del sector agrícola. Por ello, en este documento se brindan propuestas para la toma de decisiones en dos regiones naturales del Perú (costa y sierra). Resulta necesario promover planes de aprovechamiento sostenible de recursos hídricos, priorizar cultivos con mejor adaptabilidad en regiones de latitudes medias o altas, establecer laboratorios especializados de control de calidad, e implementar metodologías para la evaluación de riesgos bajo diferentes escenarios agroclimáticos

Influencia del tipo de sistema de aireación difuso en la eficiencia de transferencia de oxígeno en aguas residuales domésticas Huancayo-2020

En los tratamientos de aguas residuales domésticas de tipo biológico, una de las etapas que orienta a un mayor gasto energético es la aireación, resultando un elemento crítico cuando se pretende evaluar la elección de un sistema para el tratamiento de estas aguas. Ante esto, en la presente investigación se planteó como objetivo principal explicar la influencia del tipo de sistema de aireación difuso en la eficiencia de transferencia de oxígeno en aguas residuales domésticas. Para ello, se desarrollaron pruebas experimentales de aireación que permitieron obtener datos de oxígeno disuelto, velocidad de transferencia de oxígeno, coeficiente global de trasferencia de masa y la eficiencia de transferencia de oxígeno empleando tres tipos de sistemas de aireación difuso (burbuja fina, burbuja gruesa y burbuja extragruesa). Con los resultados obtenidos, se llegó a establecer que, el tipo de sistema de aireación difuso tiene un efecto significativo en la eficiencia de transferencia de oxígeno ya que disminuye a medida que la concentración de oxígeno disuelto se incrementa. Finalmente, en todos los experimentos el tipo de sistema de aireación difuso A (burbuja fina) obtuvo los valores más representativos

Understanding Designer Mental Models to Support Computer Directed Analogical Design

Analysis of alternative concepts has a significant impact on design project outcomes, and yet many design teams fail to consider a significantly broad range of conceptual solutions. Within the realm of conceptual design exists a technique called design by analogy (DBA) -- the practice of reapplying old solutions to new problems. DBA mitigates the effort required to generate a large field of candidate concepts by leveraging existing knowledge from a wide variety of domains, making it an attractive approach toward improving design outcomes. Unfortunately, DBA is challenging in the absence of expert knowledge. Designers need computational support in order to effectively identify a large number of high-quality analogical connections across a wide variety of domains. With this challenge in mind, the goal of this dissertation is to improve the body of knowledge regarding computational support for design by analogy. More specifically, this body of work includes five manuscripts. Manuscript 0 presents a review of several function-related design abstractions, including their impacts on education and industry. Manuscript 1 studies analogy retrieval in a novel design context and catalogs the types of abstract similarity (including function) commonly used to form analogies. Manuscript 2 examines a scalable approach to capturing analogy-relevant design knowledge to support large-scale analogy searching. Manuscripts 3 and 4 examine and modify a technique from de novo drug design for quickly indexing and retrieving design analogies. Manuscript 3 examines the domain independence of the technique, and manuscript 4 develops it as a large-scale design analogy search method. The body of work contributes to a greater understanding of (1) the abstractions used by designers during conceptual design, (2) the use of human computation to support conceptual design activities, and (3) large scale solution screening using a variety of mixed design abstractions. This understanding advances the creation of tools that enable designers to consider a wide range of conceptual solutions in spite of lacking domain expertise