12 research outputs found
Scalability, memory issues and challenges in mining large data sets
(c) 2014 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.Data mining is an active field of research and development aiming to automatically extract "knowledge" from analyzing data sets. Knowledge can be defined in different ways such as discovering (structured, frequent, approximate, etc.) patterns in data, grouping/clustering/bi-clustering data according to one or more criteria, finding association rules, etc. Such knowledge is then fed-back to decision support systems enabling end-users (actors) to make more informed decisions, which in economic terms could lead to advantages as compared to traditional decision support systems. It should be noted however, that data mining algorithms and frameworks have been proposed prior to the "Big Data" explosion. While data mining algorithms have considered efficiency and computational complexity as an important requirement, they did not take into account features of Big Data such as very large size, velocity with which data is generated, variety, etc. On the other hand, these features are indeed posing issues and challenges to data mining algorithms and frameworks. In this paper we analyse some of the issues in mining large data sets such as scalability and in-memory needs. We also show some computational results pointing out to such issues.Peer ReviewedPostprint (author's final draft
An auction framework for DaaS in cloud computing and its evaluation
Data-as-a-service (DaaS) is the next emerging technology in cloud computing research. Small clouds operating as a group may exploit the DaaS efficiently to perform the substantial amount of work. In this paper, an auction framework is studied and evaluated when the small clouds are strategic in nature. We present the system model and formal definition of the problem and its experimental evaluation. Several auction DaaS-based mechanisms are proposed and their correctness and computational complexity is analysed. To the best of our knowledge, this is the first and realistic attempt to study the DaaS in a strategic setting. We have evaluated the proposed approach under various simulation scenarios to judge on its usefulness and efficiencyPeer ReviewedPostprint (author's final draft
SIGNAGE YANG INFORMATIF DAN INTERAKTIF PADA THE HERITAGE PALACE KOTA SURAKARTA JAWA TENGAH
The Heritage Palace is located in Surakarta City of Central Java which formerly was the sugar factory that is currently used as a tourist attraction. However, this place has the problem of lacking its informative and interactive signage, less by the branding of the tourist spots, and less proper in material selection. The data collection used were the literature study, observation, interviews and questionnaires, using comparison matrix as data analysis method. The concept of the design takes the modern and old heritage concept using a font that matches the clear language and adds pictogram. The purpose of this design is to provide informative and interactive information using signage ang interactive media that is useful to help visitors get information when they visit the tourist sit
An adaptive event-based system for anytime, anywhere, awareness services in online teamworks
The fast development in mobile technologies is drastically changing the way people work, learn, collaborate and socialise. One such important activity that has emerged and is being consolidated more each time is the online learning through virtual campuses. While most of online learning services are at present offered through web-based platforms, due to ever-increasing use of smart devices such as smartphones and tablets, researchers and developers are paying attention to exploit the advantages of mobile systems to support online learning. Specifically, the implementation of the A3 paradigm: anytime, anywhere, awareness - that is, notifying users about ongoing activity in their online workspace - provides various advantages to online learners organised in online teams. In this paper, we present the requirement analysis, the building blocks of the architecture for efficient event-based system and a prototype implementation of the A3 paradigm that adaptively supports the online collaborative activity.Peer ReviewedPostprint (author's final draft
Energy Efficient Scheduling Methods for Computational Grids and Clouds, Journal of Telecommunications and Information Technology, 2017, nr 1
This paper presents an overview of techniques developed to improve energy efficiency of grid and cloud computing. Power consumption models and energy usage proles are presented together with energy efficiency measuring methods. Modeling of computing dynamics is discussed from the viewpoint of system identication theory, indicating basic experiment design problems and challenges. Novel approaches to cluster and network-wide energy usage optimization are surveyed, including multi-level power and software control systems, energy-aware task scheduling, resource allocation algorithms and frameworks for backbone networks management. Software-development techniques and tools are also presented as a new promising way to reduce power consumption at the computing node level. Finally, energy-aware control mechanisms are presented. In addition, this paper introduces the example of batch scheduler based on ETC matrix approach
Taxonomy of digital signage message execution and media placement considerations
Digital signage is a commercial promising field in marketing. Yet, it is a little researched topic, with an incomplete understanding of the factors to consider when planning digital signage message executions or media placements. There is no systematic, cohesive foundation to describe and study the features of this promising contemporary digital platform. This paper addresses an academic-practitioner divide by developing an orderly categorisation of digital signage message execution and media placement considerations and research. It offers a well-ordered conceptualisation of digital signage types and guidelines for selecting content types, formats, display quality and technical interactive designs. The resulting taxonomy is of relevance to retailers and marketers aiming to optimise utilitarian or hedonic value. Some guidance for prospect research is provided, particularly assessing the varies opportunities offered by different digital signage content types; designing experiments compare the effectiveness of digital display quality, sizes, placement and designs at different locations. The possible obstacles of interactive digital signage also deserve future research
Object-based Information Flow Control in Peer-to-peer Publish/Subscribe Systems
Distributed systems are getting so scalable like IoT (Internet of Things) and P2P (Peer-to-Peer) systems that millions of devices are connected and support various types of applications. Here, distributed systems are required to be secure in addition to increasing the performance, reliability, and availability and reducing the energy consumption. In distributed systems, information in objects flows to other objects by transactions reading and writing data in the objects. Here, some information of an object may illegally flow to a subject which is not allowed to get the information of the object. Especially, a leakage of sensitive information is to be prevented from occurring. In order to keep information systems secure, illegal information flow among objects has to be prevented. Types of synchronization protocols are so far discussed based on read and write access rights in the RBAC (Role-Based Access Control) model to prevent illegal information flow.In this thesis, we newly propose a P2PPSO (P2P type of topic-based PS (Publish/Subscribe) with Object concept) model and discuss the models and protocols for information flow control. A P2PPSO model is composed of peer processes (peers) which communicate with one another by publishing and subscribing event messages. Each peer can both publish and receive event messages with no centralized coordinator compared with traditional centralized PS models. Each event message published by a source peer carries information to a target peer. The contents carried by an event message are considered to be composed of objects. An object is a unit of data resource. Objects are characterized by topics, and each event message is also characterized by topics named publication topics.In order to make a P2PPSO system secure, we first newly propose a TBAC (Topic-Based Access Control) model. Here, an access right is a pair ⟨t, op⟩ of a topic t and a publish or subscribe operation op. A peer is allowed to publish an event message with publication topics and subscribe interesting topics only if the publication and subscription access rights are granted to the peer, respectively. Suppose an event message e_j published by a peer p_j carries an object on some topics into a target peer p_i. Here, information in the peer p_j illegally flows to the peer p_i if the target peer p_i is not allowed to subscribe the topics. An illegal object is an object whose topics a target peer is not allowed to subscribe. Even if an event message is received by a target peer by checking topics, objects carried by the event message may be illegal at the target peer. Hence, first, we propose a TOBS (Topics-of-Objects-Based Synchronization) protocol to prevent target peers from being delivered illegal objects in the P2PPSO system. Here, even if an event message is received by a target peer, illegal objects in the event message are not delivered to the target peer.In the TOBS protocol, every event message is assumed to be causally delivered to every common target peer in the underlying network. Suppose an event message e_2 is delivered to a target peer p_i before another event message e_1 while the event message e_1 causally precedes the event message e_2 (e_1 →_c e_2). Here, the event message e_2 is premature at the peer p_i. Hence, secondly, we propose a TOBSCO (TOBS with Causally Ordering delivery) protocol where the function to causally deliver every pair of event messages is added to the TOBS protocol. Here, we assume the underlying network supports reliable communication among every pair of peers, i.e. no event message loss, no duplicate message, and the sending order delivery of messages. Every pair of event messages received by using topics are causally delivered to every common target peer by using the vector of sequence numbers.In the TOBS and TOBSCO protocols, objects delivered to target peers are held as replicas of the objects by the target peers. If a peer updates data of an object, the peer distributes event messages, i.e. update event messages, to update every replica of the object obtained by other peers. If a peer updates an object without changing topics, the object is referred to as altered. Here, an update event message for the altered object is meaningless since peers check only topics to exchange event messages. Hence, thirdly, we propose an ETOBSCO (Efficient TOBSCO) protocol where update event messages of objects are published only if topics of the objects are updated to reduce the network overhead.In the evaluation, first, we show how many numbers of event messages and objects are prevented from being delivered to target peers in the TOBS protocol. Next, we show every pair of event messages are causally delivered but it takes longer to deliver event messages in the TOBSCO protocol than the TOBS protocol. Finally, we show the fewer number of event messages are delivered while it takes longer to update replicas of altered objects in the ETOBSCO protocol than the TOBSCO protocol.博士(工学)法政大学 (Hosei University
A retrospective and contemporary analysis of service-dominant logic
Service-Dominant (SD) Logic hat sich als eine der führenden Ansätze in der aktuellen
Literatur der Dienstleistungsforschung (engl.: Service Science) etabliert. Dieser
Ansatz, erstmals im Jahr 2004 erwähnt, entstand nachdem sich das Feld der
Dienstleistungswissenschaft bereits viele Jahre entwickelt hatte. Anstatt allein auf die
Produktion und Vermarktung von Gütern zu fokussieren, unterstreicht dieser
Denkansatz wie Organisationen, Märkte und die Gesellschaft auf Basis der
Anwendung von Kompetenzen besser verstanden werden können. Die vorliegende
Arbeit widmet sich zuerst einem Rückblick durch die Analyse der historischen
Entwicklung der Dienstleistungswissenschaft von ihren Anfängen bis hin zur aktuell
dominierenden SD Logic-Perspektive. Hierauf folgt eine detaillierte Literaturanalyse
des Zeitraums 2004 bis 2011, in der über 100 veröffentliche wissenschaftliche
Arbeiten zum Thema SD Logic in Betracht gezogen werden. Die wichtigsten Studien
zum Thema SD Logic wurden mittels Recherche in den wichtigsten
betriebswirtschaftlichen Datenbanken sowie durch Cross-Referencing-Methoden
ermittelt. Diese Arbeiten wurden systematisch hinsichtlich ausgewählter Attribute
analysiert, nämlich Autor, Zeitschrift und Erscheinungsjahr der Veröffentlichung,
Forschungsfeld, verwendete Methode, Schlagwörter sowie Resultate der
Veröffentlichungen. Die Ergebnisse präsentieren die wichtigsten Autoren im SD
Logic Bereich, diskutieren die empirischen Erkenntnisse und zeigen auf, in welchem
Ausmaß SD Logic in anderen Bereichen als Marketing behandelt werden. Man kann
beobachten, dass diesem Thema vermehrt Aufmerksamkeit geschenkt wird und auch
dass sich ein vermehrt interdisziplinärer Fokus in Richtung SD-basierter Forschung
etabliert. Dies unterstreicht die Bedeutung der aktuell dominierenden Perspektive auf
gegenseitigen Serviceaustausch und einer kollaborativen Wertschöpfung.Service-Dominant (SD) Logic has developed as a dominant perspective in
contemporary Service Science literature. This mind-set, introduced in 2004, emerged
after the Service Science field underwent several decades of development. Instead of
focusing on simple production and marketing of goods, this way of thinking
emphasises how the nature of organizations, markets and society can be better
understood on the basis of employment of competences. This thesis first takes a
retrospective view by analysing the historical development of this mind-set, starting
with marketing dominated roots of Service Science, towards today’s dominant
perspective based on SD Logic. Next, a detailed literature analysis for the period 2004
to 2011 is undertaken in order to list and review over 100 published studies dealing
with SD Logic. The major business-economic scientific databases were researched,
and cross-referencing techniques were used to extract key studies dealing with SD
Logic. These findings are systematically analysed regarding author(s), journal and
year of publication, research area, applied research methodologies, keywords and
output. Findings present key players, discuss the share of empirical results and outline
the extent of application in areas other than those of the marketing discipline. The
analysis serves as powerful evidence confirming the increased ‘momentum’ of SD
Logic. Increased attention as well as an increasingly interdisciplinary focus for SD
grounded research efforts is observed, underlining the importance of a currently
dominant view on mutual service exchange and value co-creation