The Ubiquity of Large Graphs and Surprising Challenges of Graph Processing: Extended Survey

Graph processing is becoming increasingly prevalent across many application domains. In spite of this prevalence, there is little research about how graphs are actually used in practice. We performed an extensive study that consisted of an online survey of 89 users, a review of the mailing lists, source repositories, and whitepapers of a large suite of graph software products, and in-person interviews with 6 users and 2 developers of these products. Our online survey aimed at understanding: (i) the types of graphs users have; (ii) the graph computations users run; (iii) the types of graph software users use; and (iv) the major challenges users face when processing their graphs. We describe the participants' responses to our questions highlighting common patterns and challenges. Based on our interviews and survey of the rest of our sources, we were able to answer some new questions that were raised by participants' responses to our online survey and understand the specific applications that use graph data and software. Our study revealed surprising facts about graph processing in practice. In particular, real-world graphs represent a very diverse range of entities and are often very large, scalability and visualization are undeniably the most pressing challenges faced by participants, and data integration, recommendations, and fraud detection are very popular applications supported by existing graph software. We hope these findings can guide future research

Web Server Performance of Apache and Nginx: A Systematic Literature Review

Web Server performance is cardinal to effective and efficient Information communication. Performance measures include response time and service rate, memory usage, CPU utilization among others. A review of various studies indicates a close comparison among different web servers that included Apache, IIS, Nginx and Lighttpd among others. The results of various studies indicates that response time, CPU utilization and memory usage varied with different web servers depending on the model used. However, it was found that Nginx out performed Apache on many metrics that included response time, CPU utilization and memory usage. Nginx performance under these metrics showed that its memory (in case of memory) does not increase with increased requests. It was concluded that though Nginx out performed Apache, both web servers are powerful, flexible and capable and the decision of which web server to adopt is entirely dependent on the need of the user. Since some metric such as uptime (the amount of time that a server stays up and running properly) which reflects the reliability and availability of the server and also landing page speed was not included, we propose that future studies should consider uptime and landing page speed in the testing of web server performance. Keywords: web server, web server performance, apache, Ngin

GoOrg: a model to automatically design organisations for multi-agent systems

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia de Automação e Sistemas, Florianópolis, 2023.O design de organizações é uma tarefa complexa e trabalhosa. Isto é tema de estudos recentes que definem modelos para executar esta tarefa automaticamente. No entanto, os modelos existentes restringem o espaço de possíveis soluções requisitando definições prévias dos papéis organizacionais e geralmente não são adequados para o planejamento de recursos. Esta tese de doutorado apresenta o GoOrg, um modelo que utiliza como entrada um conjunto de objetivos e um conjunto de agentes disponíveis para gerar diferentes arranjos de estruturas organizacionais construídas a partir de posições organizacionais sintetizadas. As características mais distintas do GoOrg é o uso de posições organizacionais ao invés de papéis e que as posições são sintetizadas automaticamente no lugar de requisitar que o usuário as defina. Estas características facilitam a parametrização, a utilização no planejamento de recursos e as chances do modelo de encontrar soluções viáveis. Para avaliar o GoOrg, esta tese introduz duas especializações que estendem o modelo. Estas extensões definem processos e restrições, ilustrando como o GoOrg pode ser adequado para diferentes domínios. Entre os aspectos associados ao design de organizações, este trabalho apresenta uma comparação entre modelos de design organizacional e discute entradas, abstrações de agentes e procedimentos para adaptação de organizações durante seu ciclo de vida.Abstract: The design of organisations is a complex and laborious task. It is the subject of recent studies, which define models to automatically perform this task. However, existing models constrain the space of possible solutions by requiring a priori definitions of organisational roles and usually are not suitable for planning resource use. This doctoral thesis presents GoOrg, a model that uses as input a set of goals and a set of available agents to generate different arrangements of organisational structures made up of synthesised organisational positions. The most distinguishing characteristics of GoOrg are the use of organisational positions instead of roles and that positions are automatically synthesised rather than required as a user-defined input. These characteristics facilitate the parametrisation, the use for resource planning and the chance of finding feasible solutions. To evaluate GoOrg, this thesis introduces two specialisations that extend the model. These extensions define processes and constraints, illustrating how GoOrg suits different domains. Among aspects that surround an organisation's design, this work presents a comparison of design models and discusses models input, agents' abstractions and procedures for adapting the organisation during its life cycle

Analysis of Software Design Patterns in Human Cognitive Performance Experiments

As Air Force operations continue to move toward the use of more autonomous systems and more human-machine teaming in general, there is a corresponding need to swiftly evaluate systems with these capabilities. We support this development through software design improvements of the execution of human cognitive performance experiments. This thesis sought to answer the following two research questions addressing the core functionality that these experiments rely on for execution and analysis: 1) What data infrastructure software requirements are necessary to execute the experimental design of human cognitive performance experiments? 2) How effectively does a central data mediator design pattern meet the time-alignment requirements of human cognitive performance studies? To answer these questions, this research contributes an exploration of establishing design patterns to reduce the cost of conducting human cognitive performance studies. The activities included in this exploration were a method for requirements gathering, a meta-study of recent experiments, and a design pattern evaluation all focused on the experimental design domain

The Role of Age in Technology-induced Workplace Stress

Recent research shows that such Information and Communication Technologies (ICTs) as instant messengers can cause workplace interruptions, which lead to stress for employees and substantial productivity losses for U.S. organizations. Since the introduction of ICTs, workplace interruptions have evolved in both frequency and nature from irregular phone calls to a continuous stream of e-mail notifications and other electronic interruptions, mediated through a large number of technological devices that constantly beep and buzz. This trend of an increasing frequency of workplace interruptions closely relates to another workplace trend: the graying of the workforce, implying that the U.S. workforce is aging at an increased rate. Since older people are particularly vulnerable to interruptions, the interdependencies inherent in these two workplace trends need to be better understood. Accordingly, this dissertation aims to understand whether, how, and why technology-mediated (T-M) interruptions impact stress and task performance differently for older compared to younger adults. To examine these questions, this research applies two complementary theoretical frames that explain interruptions\u27 influence on older and younger adults\u27 cognition. First, the Person-Environment Fit perspective suggests that T-M interruptions may lessen the fit between the mental resources available for performing a task and those required, thereby inducing workplace stress and, in turn, reducing individual task performance. Second, the Inhibitory Deficit Theory of Cognitive Aging holds that older peoples\u27 ability to actively disregard distracting stimuli is impaired. Thus, more T-M interruptions may \u27steal\u27 resources from the processing of task-related content in older adults. In combining these theories with user characteristics and technology features, this research develops an integrative model of ICTs, aging, stress, and task performance. We propose that older people are more distracted by T-M interruptions than younger, thereby experiencing greater mental workload and, in turn, more stress and lower performance. We test the model through a laboratory experiment that integrates the manipulation of ICT features with objective measures of stress and task performance, unlike the subjective measures commonly used. Experimental manipulations include the frequency with which interruptions appear as well as such interruption design characteristics as color codes. Outcome measures include actual performance in terms of the number of task elements solved, as well as the change in stress hormones found in saliva, a state-of-the art physiological measure of stress. In developing and testing the model, we help to clarify the role of age in technostress. This research also sheds more light on the mental processes that connect ICTs to stress and performance, and it has begun to open the black box of the ICT features linked to these outcomes. For managers, we provide guidance on assisting older employees in realizing their full potential for contributing to firm success. This research further advises systems designers on such issues as user involvement

Emergent software systems

Contemporary software systems often have millions of lines of code that interact over complex infrastructures. The development of such systems is very challenging due to the increasing complexity of services and the high level of dynamism of current operating environments. In order to support the development and management of such systems, autonomic computing concepts have gained significant importance. The majority of autonomic computing approaches show significant levels of expert dependency in designing adaptive solutions. These approaches usually rely on human-made models and policies to support and guide software adaptation at runtime. These approaches mainly suffer from: i) a significant upfront effort demanded to create such solutions, which adds to the complexity of creating autonomous systems, and ii) unreliability given the high levels of uncertainty in current operating environments, leading the system to degraded performance and error states when subjected to unpredicted operating conditions and unexpected software interactions. Motivated by the problems and limitations of state-of-the-art autonomic computing solutions, this thesis introduces the concept of Emergent Software Systems. These systems are autonomously composed at runtime from discovered components, and are autonomously optimised based on the operating conditions, being able to build their own understanding of their environment and constituent parts. This thesis defines Emergent Software Systems, presenting the challenges of implementing such approach, and presents a fully functioning emergent systems framework that demonstrates this concept in real-world, fully functioning datacentre-based software

RISCS Annual Report 2018

The Research Institute in Science of Cyber Security (RISCS) takes an evidence-based and interdisciplinary approach to addressing cyber security challenges. By providing a platform for the exchange of ideas, problems and research solutions between academia, industry, and both the UK and international policy communities, RISCS promotes and supports the development of scientific approaches to cyber security. Central to the RISCS agenda is the application of bodies of knowledge to stimulate a transition from ‘common practice’ to ‘evidence-based best practice’ in cyber security. Recognising that cyber security is a contested concept, RISCS operates within a national and international cyber security framework to establish a coherent set of research principles. These principles focus on the deployment of scientific methods and the gathering of evidence to produce sound interventions and responses to cyber security challenges. We actively seek to maximise collaboration amongst our diverse community through a culture of open publication, sharing and expanding our network. Through this collaboration, RISCS develops techniques that enable communities to anticipate emergent cyber security issues from public policy, social practice and technological perspectives. Our end goal is to deliver a world-class portfolio of activity and research findings that maximises the value of social, political and economic research into cyber security and which results in a set of scientifically based options that individuals, institutions and nation states can use to respond to imminent and long term cyber security challenges

Improving the Indico Framework at the European Organization for Nuclear Research - Internship Report - LEIC 2006/2007 (FEUP)

This document describes the work developed by José Pedro Macedo Alves Ferreira, Informatics Engineering and Computing (LEIC) undergraduate student at the Engineering Faculty of the University of Porto (FEUP), in the context of the project "Improving the Indico Framework". The project took place at the European Organization for Nuclear Research (CERN), in the framework of both the Technical Student Program of this organization, and the curricular internship of the aforementioned degree. The contents of this report refer to the internship period, the first half of the one-year Technical Student program. The project aimed to introduce usability improvements into an already existing web application, the Indico platform, a integrated system for event scheduling and management, which was initially developed as a European project and continued by CERN, being currently used by several institutions worldwide. Indico presented some usability issues that for long had been noticed by the users and required correction, mainly problems in the navigation process (event browsing), and the lack of user-centered features (i.e. a "personal area"). Initially, a thorough usability study was put in motion, including not only "checklist-based" analysis but "user-centered" approaches as well. A user survey and a laboratory test were conducted, and their results evaluated and taken into account in the definition of recommendations and requirements. Th e requirements whose priority was higher were selected, and functional prototypes were designed and implemented. This included an integrated search feature, a "favorite users" system, a personal area, and a contextual help system. The result of the project was a set of prototypes, compliant with the previously defined recommendations, and ready to be included in the production version of Indico. The objectives were accomplished, and the project entered a new phase, in which the user interface will be totally refurbished, in order to comply with the established requirements, and the developed prototypes will be introduced as normal features, available to the regular user