Search results for "reliability"
showing 10 items of 1563 documents
Charge Transport Mechanisms in Heavy-Ion Driven Leakage Current in Silicon Carbide Schottky Power Diodes
2016
Under heavy-ion exposure at sufficiently high reverse bias voltages silicon carbide (SiC) Schottky diodes are observed to exhibit gradual increases in leakage current with increasing ion fluence. Heavy-ion exposure alters the overall reverse current-voltage characteristics of these diodes, leaving the forward characteristics practically unchanged. This paper discusses the charge transport mechanisms in the heavy-ion damaged SiC Schottky diodes. A macro model, describing the reverse current-voltage characteristics in the degraded SiC Schottky diodes is proposed. peerReviewed
Supporting employee engagement with internal communication for high reliability
2015
Tämä pro gradu-työ tarkastelee kirjallisuuden ja empiirisen tutkimuksen avulla työntekijöiden sitoutumista organisaatioissa, joiden toiminnalle korkea luotettavuusvaatimus on edellytys. Työntekijöiden sitoutuminen ja sen merkitys organisaation menestykselle on noussut kiinnostuksenkohteeksi niin käytännössä kuin akateemisen tutkimuksen piirissä. Sisäinen viestintä on yksi väline jolla sitoutumista voi tukea organisaatiossa, ja sillä on myös merkitystä organisaation toimintavarmuudelle. Työ on laadullinen tutkimus, joka toteutettu pääosin abduktiivisella tutkimusmetodilla. Työssä on sekä teoreettinen että empiirinen osuus. Teoriaosuus käsittelee työntekijöiden sit…
PQ and Harmonic Assessment Issues on Low-Cost Smart Metering Platforms: A Case Study
2020
This paper presents a feasibility study on how to implement power quality (PQ) metrics in a low-cost smart metering platform. The study is aimed at verifying the possibility of implementing PQ monitoring in distribution networks without replacing existing smart metering devices or adding new modules for PQ measurements, thus zeroing the installation costs. To this aim, an electronic board, currently used for remote energy metering, was chosen as a case study, specifically the STCOMET platform. Starting from the specifications of this device, the possibility of implementing power quality metrics is investigated in order to verify if compliance with standard requirements for PQ instruments ca…
Joint second-order parameter estimation for spatio-temporal log-Gaussian Cox processes
2018
We propose a new fitting method to estimate the set of second-order parameters for the class of homogeneous spatio-temporal log-Gaussian Cox point processes. With simulations, we show that the proposed minimum contrast procedure, based on the spatio-temporal pair correlation function, provides reliable estimates and we compare the results with the current available methods. Moreover, the proposed method can be used in the case of both separable and non-separable parametric specifications of the correlation function of the underlying Gaussian Random Field. We describe earthquake sequences comparing several Cox model specifications.
Vertikaalihypyn korkeuden arviointi 3D-kiihtyvyysanturilla ja lajinomaisen kuormituksen vaikutukset hyppyyn
2016
Sensoreihin perustuvat menetelmät ovat yleistyneet urheilutestauksessa viime vuosina. Tarkoituksena oli selvittää hyppääjän kenkään kiinnitettävään 3D-kiihtyvyysanturiin perustuvan menetelmän validiteettia vertikaalihypyn korkeuden arvioinnissa. Voimalevyn lentoaikamenetelmää käytettiin kiihtyvyysanturimenetelmän validiteettianalyysissä ja lajikohtaisten kuormitusasetelman vertikaalihypyt arvioitiin kiihtyvyysanturimenetelmällä. Hyppysarjojen korkeimmat hypyt arvioitiin lisäksi voimalevyn lähtönopeusmenetelmällä. Kiihtyvyysanturimenetelmässä käytettiin urheilijan kenkään kiinnitettävää The Stride Sensor Bluetooth® Smart (Polar Electro Oy, Kempele, Suomi) -sensoria. Hyppytestit suoritettiin …
Test-retest reliability of survey items on ownership and use of physical activity trackers
2019
Background: Researchers are interested in using digital tools, such as physical activity trackers (PAT), to promote and measure physical activity. PAT is a fast-growing research area that measures movement therefore, reliable questions on the ownership and use of PATs among adolescent populations need to be developed. Objective: The aim of this study was to conduct an intra-rater test-retest reliability study on PAT survey items used for surveillance purposes among young adolescents in ownership and use of smartphone applications (apps) and heart rate monitors (HRM). Methods: Young adolescents (N = 755; 11-, 13-, and 15-year-olds) in the Olomouc region of the Czech Republic were recruited t…
Dog-Owner Relationship, Owner Interpretations and Dog Personality Are Connected with the Emotional Reactivity of Dogs
2022
Simple Summary The relationship between owner and the dog affects the dog's attachment behaviors and stress coping. In turn, the quality of the relationship may affect owner's interpretations about their dog's behavior. Here, we assessed dogs' emotional responses from heart rate variability and behavioral changes during five different situations. Dog owners evaluated the emotion (valence and arousal) of their dog after each situation. We found that both negative and positive incidents provoked signs of emotional arousal in dogs. Owners detected the dog's arousal especially during fear- and stress-evoking situations. The dog-owner relationship did not affect owners' interpretation of dogs' e…
Critical Analysis on the NHTSA Acceptance Criteria for In-Vehicle Electronic Devices
2014
We tested a commercial in-car navigation system prototype against the NHTSA criteria for acceptance testing of in-vehicle electronic devices, in order to see what types of in-car tasks fail the acceptance test and why. In addition, we studied the visual demands of the driving scenario recommended by NHTSA for task acceptance testing. In the light of the results, NHTSA guidelines and acceptance criteria need to be further developed. In particular visual demands of the driving scenario and for different simulators need to be standardized in order to enable fair testing and comparable test results. We suggest the visual occlusion method for finding a driving scenario that corresponds better wi…
Data mining framework for random access failure detection in LTE networks
2014
Sleeping cell problem is a particular type of cell degradation. There are various software and hardware reasons that might cause such kind of cell outage. In this study a cell becomes sleeping because of Random Access Channel (RACH) failure. This kind of network problem can appear due to misconfiguration, excessive load or software/firmware problem at the Base Station (BS). In practice such failure might cause network performance degradation, which is hardly traceable by an operator. In this paper we present a data mining based framework for the detection of problematic cells. In its core is the analysis of event sequences reported by a User Equipment (UE) to a serving BS. The choice of N i…
Visual Distraction Effects of In-Car Text Entry Methods
2017
Three text entry methods were compared in a driving simulator study with 17 participants. Ninety-seven drivers’ occlusion distance (OD) data mapped on the test routes was used as a baseline to evaluate the methods’ visual distraction potential. Only the voice recognition-based text entry tasks passed the set verification criteria. Handwriting tasks were experienced as the most demanding and the voice recognition tasks as the least demanding. An individual in-car glance length preference was found, but against expectations, drivers’ ODs did not correlate with incar glance lengths or visual short-term memory capacity. The handwriting method was further studied with 24 participants with instru…