Search results for "network"
showing 10 items of 7718 documents
Shared and personal learning spaces: Challenges for pedagogical design
2012
Abstract The development of new tools for collaboration, such as social software, plays a crucial role in leisure time and work activities. The aim of this article is to summarize the research in the field of computer-supported collaborative learning (CSCL). This is done particularly from the perspective of the blurred line between individual (personal) and group-level (shared) learning that the use of the new tools has forced us to re-think. First, individual and group-level perspectives to learning are discussed to make sense of the major notions of how learning is understood in CSCL research. Second, based on this theoretical grounding, it will be further elaborated what this means to th…
Two-phase routing in three-dimensional blocked optical tori
2014
The contribution of this paper is an all-optical 3D network architecture. We describe scheduled, two-phase routing for it. The three-dimensional blocked optical torus BOT of block size b consists of b2 × b2 × b2 nodes for the first phase routing. Processors are evenly deployed at the underlying torus so that every bth node consists of a processor. Additionally, a BOT consists of b3 blocks of b × b × b subnetworks for the second phase routing. Routing of each packet is done in two phases. Firstly, packets are routed from source processor to an intermediate target node at the target block. Secondly, packets are routed from the intermediate targets at the target block to the target processor (…
Anomaly Detection Algorithms for the Sleeping Cell Detection in LTE Networks
2015
The Sleeping Cell problem is a particular type of cell degradation in Long-Term Evolution (LTE) networks. In practice such cell outage leads to the lack of network service and sometimes it can be revealed only after multiple user complains by an operator. In this study a cell becomes sleeping because of a Random Access Channel (RACH) failure, which may happen due to software or hardware problems. For the detection of malfunctioning cells, we introduce a data mining based framework. In its core is the analysis of event sequences reported by a User Equipment (UE) to a serving Base Station (BS). The crucial element of the developed framework is an anomaly detection algorithm. We compare perfor…
A modelling framework for social media monitoring
2013
This paper describes a hierarchical, three-level modelling framework for monitoring social media. Immediate social reality is modelled through the first level of the models. They represent various virtual communities at social media sites and adhere to the social world models of the sites, i.e., the "site ontologies". The second-level model is a temporal multirelational graph that captures the static and dynamic properties of the first-level models from the perspective of the monitoring site. The third-level model consists of a temporal relational database scheme that models the temporal multirelational graph within the database. The models are specified and instantiated at the monitoring s…
Twister Tries
2015
Many commonly used data-mining techniques utilized across research fields perform poorly when used for large data sets. Sequential agglomerative hierarchical non-overlapping clustering is one technique for which the algorithms’ scaling properties prohibit clustering of a large amount of items. Besides the unfavorable time complexity of O(n 2 ), these algorithms have a space complexity of O(n 2 ), which can be reduced to O(n) if the time complexity is allowed to rise to O(n 2 log2 n). In this paper, we propose the use of locality-sensitive hashing combined with a novel data structure called twister tries to provide an approximate clustering for average linkage. Our approach requires only lin…
Comparing the cost-efficiency of CoAP and HTTP in Web of Things applications
2014
Abstract Constrained Application Protocol (CoAP) has been introduced as a simpler alternative to the Hypertext Transfer Protocol (HTTP) for connecting constrained smart objects to the Web. The adoption of the protocol depends on its relative advantage, and the cost–benefit associated with the use of the protocol is a significant factor affecting a protocol adoption decision. This paper aims at deepening the understanding of the cost–benefits of CoAP and identifies the application scenarios where its use is likely to be economically justifiable. The paper analyzes the costs of using CoAP and HTTP in the Web of Things (WoT) applications, by identifying the components of the total cost of owne…
Value Creation and Evolution of a Value Network: A Longitudinal Case Study on a Platform-as-a-Service Provider
2014
Current research on cloud computing emphasizes the important role of Platform-as-a-Service (PaaS) providers. However, little is known about how PaaS providers can offer value to the content providers and firms operating the platform. The findings demonstrate how a small PaaS provider in the cloud gaming market was able to develop a strong position in the value network by offering direct and indirect value to its partners. The findings also reveal how the firm developed its value network over fourteen years, from a complex network with several actors to a very simple value network which included only partners of prime importance. peerReviewed
Introduction to Integrating Knowledge and Learning Processes Minitrack
2013
This minitrack discusses knowledge management (KM) from an integrated perspective, i.e., the integration of KM, learning, and business processes. It mainly focuses on two issues: a) how can knowledge, learning and business processes integrated, and b) how can the related systems be integrated to enable an efficient workflow. Currently, even less learning environments take context and environment into account. Using mobile and ubiquitous technologies can lead to a paradigm shift in the construction of such learning environments: from static to highly contextualized knowledge and learning experiences. Based on the integration of knowledge and learning systems into social networks and social m…
Linear fusion of interrupted reports in cooperative spectrum sensing for cognitive radio networks
2015
Interrupted reporting has recently been introduced as an effective method to increase the energy efficiency of cooperative spectrum sensing schemes in cognitive radio networks. In this paper, joint optimization of the reporting and fusion phases in a cooperative sensing with interrupted reporting is considered. This optimization aims at finding the best weights used at the fusion center to construct a linear fusion of the received interrupted reports, jointly with Bernoulli distributions governing the statistical behavior of the interruptions. The problem is formulated by using the deflection criterion and as a nonconvex quadratic program which is then solved for a suboptimal solution, in a…
Genetic programming through bi-objective genetic algorithms with a study of a simulated moving bed process involving multiple objectives
2013
A new bi-objective genetic programming (BioGP) technique has been developed for meta-modeling and applied in a chromatographic separation process using a simulated moving bed (SMB) process. The BioGP technique initially minimizes training error through a single objective optimization procedure and then a trade-off between complexity and accuracy is worked out through a genetic algorithm based bi-objective optimization strategy. A benefit of the BioGP approach is that an expert user or a decision maker (DM) can flexibly select the mathematical operations involved to construct a meta-model of desired complexity or accuracy. It is also designed to combat bloat - a perennial problem in genetic …