Search results for "A2"

Normal-Metal–Insulator–Superconductor Tunnel Junction With Atomic-Layer-Deposited Titanium Nitride as Superconductor

2015

Voice traffic bicasting enhancements in mobile HSPA network

2014

This paper discusses methods for improving the effectiveness of delivering voice traffic over High-Speed Downlink Packet Access (HSDPA) network by employing transmission diversity with Single-Frequency Dual-Cell (SF-DC) Aggregation that is part of the Multiflow specification. SF-DC Aggregation allows the user to be served at the same time by two different cells. The enhancements discussed in the paper capitalize strongly on the availability of the composed Channel Quality Indication (CQI) feedback at both serving cells. According to the results obtained from the network simulations, the ability to select the better channel for each voice transmission significantly decreases the required tra…

Gear classification and fault detection using a diffusion map framework

2015

This article proposes a system health monitoring approach that detects abnormal behavior of machines. Diffusion map is used to reduce the dimensionality of training data, which facilitates the classification of newly arriving measurements. The new measurements are handled with Nyström extension. The method is trained and tested with real gear monitoring data from several windmill parks. A machine health index is proposed, showing that data recordings can be classified as working or failing using dimensionality reduction and warning levels in the low dimensional space. The proposed approach can be used with any system that produces high-dimensional measurement data. peerReviewed

On shape differentiation of discretized electric field integral equation

2013

Abstract This work presents shape derivatives of the system matrix representing electric field integral equation discretized with Raviart–Thomas basis functions. The arising integrals are easy to compute with similar methods as the entries of the original system matrix. The results are compared to derivatives computed with automatic differentiation technique and finite differences, and are found to be in an excellent agreement. Furthermore, the derived formulas are employed to analyze shape sensitivity of the input impedance of a planar inverted F-antenna, and the results are compared to those obtained using a finite difference approximation.

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 (…

Interactive map interface for controlling bridge crane automation A cognitive-affective approach

2016

This study outlines the development process of a new touch screen based user interface for controlling bridge crane automation in industrial environments. A user study of existing situation (n1 = 11) was used to develop an understanding of the cognitive and emotional design goals for crane operation. Conceptualization of these goals in the context of automation produced a set of requirements, which were used to develop a map-based touch screen user interface. Two field tests (n2 = 5, n3 = 5) revealed how bridge crane operators cognise and emotionally experience the increasing automation and how the user interface should be designed to support the operator’s spatial mental representation as …

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…

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…

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…

Activity Theory as a Lens to Identify Challenges in Surgical Skills Training at Hospital Work Environment

2015

In this paper the concepts from activity theory (AT) are applied for identifying the challenges and contradictions emerging in surgical resident’s curriculum based training at hospital. AT is utilised as a lens to identify contradictions that cause disturbances, problems, ruptures, breakdowns, and clashes which emerge while surgical skills training is implemented in a new way at hospital. We especially aim at finding solutions for contradictions which emerge while the new and old working culture are confronted and the workers are required to balance themselves between the patient care demands and workplace learning requirements. We are using the conceptual theoretical approach to describe…