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Lemlikchi, S., Martinsson, J., Hamrit, A., Djelouah, H., Asmani, M. & Carlson, J. E. (2019). Correction to: Ultrasonic Characterization of Thermally Sprayed Coatings [Letter to the editor]. Journal of thermal spray technology (Print), 28(3), 591
Open this publication in new window or tab >>Correction to: Ultrasonic Characterization of Thermally Sprayed Coatings
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2019 (English)In: Journal of thermal spray technology (Print), ISSN 1059-9630, E-ISSN 1544-1016, Vol. 28, no 3, p. 591-Article in journal, Letter (Refereed) Published
Abstract [en]

The first name of author Ahmed Hamrit was misspelled as “Ahmet” in the original article. Please note that the correct spelling of his name is “Ahmed” as shown in this correction. 

Place, publisher, year, edition, pages
Springer, 2019
National Category
Signal Processing Other Electrical Engineering, Electronic Engineering, Information Engineering Probability Theory and Statistics
Research subject
Mathematical Statistics; Signal Processing
Identifiers
urn:nbn:se:ltu:diva-73058 (URN)10.1007/s11666-019-00842-8 (DOI)000459400600022 ()2-s2.0-85061027570 (Scopus ID)
Note

Erratum in: Journal of Thermal Spray Technology, 2019, 28, 3, 391–404, DOI: 10.1007/s11666-019-00832-w

Available from: 2019-02-27 Created: 2019-02-27 Last updated: 2019-03-11Bibliographically approved
Lemlikchi, S., Martinsson, J., Hamrit, A., Djelouah, H., Asmani, M. & Carlson, J. E. (2019). Ultrasonic Characterization of Thermally Sprayed Coatings. Journal of thermal spray technology (Print), 28(3), 391-404
Open this publication in new window or tab >>Ultrasonic Characterization of Thermally Sprayed Coatings
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2019 (English)In: Journal of thermal spray technology (Print), ISSN 1059-9630, E-ISSN 1544-1016, Vol. 28, no 3, p. 391-404Article in journal (Refereed) Published
Abstract [en]

This paper describes the simultaneous determination of the ultrasonic parameters in thermally sprayed coatings. The parameters of interest are the longitudinal wave velocity and the ultrasonic attenuation. The test materials are two cobalt-based coatings (FSX 414 and Diamalloy 4060), both deposited onto stainless steel (310SS) substrates. The ultrasonic measurements were carried out in the pulse-echo configuration using several transducers. The ultrasonic signals reflected from the coatings were successfully estimated using the combined model, together with the maximum likelihood estimation and the Levenberg–Marquardt approach. The best estimate was obtained for 20 MHz measurements. Once the model was validated, the ultrasonic parameters of the thermally sprayed coatings were extracted. Model validation is based on the analysis of the residual between measured and estimated signals. Results showed non-dispersive ultrasonic velocities with average values of (3940±50)m/s" role="presentation" style="box-sizing: border-box; display: inline-table; line-height: normal; letter-spacing: normal; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative;">(3940±50)m/s(3940±50)m/s in Diamalloy 4060 and (4260±20)m/s" role="presentation" style="box-sizing: border-box; display: inline-table; line-height: normal; letter-spacing: normal; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative;">(4260±20)m/s(4260±20)m/s in FSX 414. High ultrasonic attenuation with a quadratic frequency dependence was observed for both materials. Moreover, it was found that the ultrasonic parameters in thermally sprayed materials are microstructure dependent. For close densities, the harder the coating, the higher the ultrasonic wave velocity and attenuation.

Place, publisher, year, edition, pages
Springer, 2019
Keywords
combined model, Diamalloy 4060, FSX 414, thermal spray coating, ultrasonic attenuation, ultrasonic wave velocity
National Category
Signal Processing Other Electrical Engineering, Electronic Engineering, Information Engineering Probability Theory and Statistics
Research subject
Mathematical Statistics; Signal Processing
Identifiers
urn:nbn:se:ltu:diva-72700 (URN)10.1007/s11666-019-00832-w (DOI)000459400600007 ()2-s2.0-85060769510 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-02-27 (svasva)

Available from: 2019-01-27 Created: 2019-01-27 Last updated: 2019-03-11Bibliographically approved
Martinsson, J. & Jonsson, A. (2018). A New Model for the Distribution of Observable Earthquake Magnitudes and Applications to b-Value Estimation. IEEE Geoscience and Remote Sensing Letters, 15(6), 833-837
Open this publication in new window or tab >>A New Model for the Distribution of Observable Earthquake Magnitudes and Applications to b-Value Estimation
2018 (English)In: IEEE Geoscience and Remote Sensing Letters, ISSN 1545-598X, E-ISSN 1558-0571, Vol. 15, no 6, p. 833-837Article in journal (Refereed) Published
Abstract [en]

The b-value in the Gutenberg–Richter (GR) law contains information that is essential for evaluating earthquake hazard and predicting the occurrence of large earthquakes. Estimates of b are often based on seismic events whose magnitude exceed a certain threshold, the so-called magnitude of completeness. Such estimates are sensitive to the choice of threshold and often ignore a substantial portion of available data. We present a general model for the distribution of observable earthquake magnitudes and an estimation procedure that takes all measurements into account. The model is obtained by generalizing previous probabilistic descriptions of sensor network limitations and using a generalization of the GR law. We show that our model is flexible enough to handle spatio-temporal variations in the seismic environment and captures valuable information about sensor network coverage. We also show that the model leads to significantly improved b-value estimates compared with established methods relying on the magnitude of completeness.

Place, publisher, year, edition, pages
IEEE, 2018
National Category
Geophysics Probability Theory and Statistics
Research subject
Mathematical Statistics
Identifiers
urn:nbn:se:ltu:diva-69044 (URN)10.1109/LGRS.2018.2812770 (DOI)000432958000007 ()2-s2.0-85044388582 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-06-05 (rokbeg)

Available from: 2018-06-01 Created: 2018-06-01 Last updated: 2018-09-14Bibliographically approved
Mishra, M., Martinsson, J., Rantatalo, M. & Goebel, K. (2018). Bayesian hierarchical model-based prognostics for lithium-ion batteries. Reliability Engineering & System Safety, 172, 25-35
Open this publication in new window or tab >>Bayesian hierarchical model-based prognostics for lithium-ion batteries
2018 (English)In: Reliability Engineering & System Safety, ISSN 0951-8320, E-ISSN 1879-0836, Vol. 172, p. 25-35Article in journal (Refereed) Published
Abstract [en]

To optimise operation and maintenance, knowledge of the ability to perform the required functions is vital. The ability is governed by the usage of the system (operational issues) and availability aspects like reliability of different components. This paper proposes a Bayesian hierarchical model (BHM)-based prognostics approach applied to Li-ion batteries, where the goal is to analyse and predict the discharge behaviour of such batteries with variable load profiles and variable amounts of available discharge data. The BHM approach enables inferences for both individual batteries and groups of batteries. Estimates of the hierarchical model parameters and the individual battery parameters are presented, and dependencies on load cycles are inferred. A BHM approach where the operational and reliability aspects end of life (EoD) and end of life (EoL) is studied where its shown that predictions of EoD can be made accurately with a variable amount of battery data. Without access to measurements, e.g. predicting a new battery, the predictions are based only on the prior distributions describing the similarity within the group of batteries and their dependency on the load cycle. A discharge cycle dependency can also be identified in the result giving the opportunity to predict the battery reliability.

Place, publisher, year, edition, pages
Elsevier, 2018
National Category
Other Civil Engineering Probability Theory and Statistics
Research subject
Operation and Maintenance; Mathematical Statistics
Identifiers
urn:nbn:se:ltu:diva-66884 (URN)10.1016/j.ress.2017.11.020 (DOI)000424960000003 ()2-s2.0-85037540599 (Scopus ID)
Note

Validerad;2018;Nivå 2;2017-12-14 (andbra)

Available from: 2017-12-04 Created: 2017-12-04 Last updated: 2018-06-13Bibliographically approved
Mishra, M., Martinsson, J., Rantatalo, M. & Goebel, K. (2018). Hierarchical model-based prognostics for Li-ion batteries. Advances In ENGINEERING
Open this publication in new window or tab >>Hierarchical model-based prognostics for Li-ion batteries
2018 (English)In: Advances In ENGINEERINGArticle in journal (Other (popular science, discussion, etc.)) Published
Abstract [en]

Recent global trend towards a fossil-fuel-free society has yielded the rapid soar in demand of electrically powered systems. Specifically, the demand for battery powered systems has fueled the desire to have better performing batteries with lithium-ion batteries being the most widely used. Presently, for application in unmanned vehicles, exploratory rovers, submarines among others demand a better comprehension of battery performance metrics. Case and point, battery capacity and state of charge have become increasingly vital when it comes to determining the end of discharge. As of now, several techniques have already been established for determining such parameters. Unfortunately, their prognostic capability for determining remaining battery charge is still not optimal. Therefore, there is a need to develop prognostic and health management technology for critical systems (such as Mars rovers) to successfully predict and manage the lifetime of batteries, monitor their health state in real time, evaluate the performance and predict the remaining useful life.

To this note, Luleå University of Technology researchers in Sweden: Dr. Madhav Mishra, Dr. Jesper Martinsson, and Dr. Matti Rantatalo in collaboration with Dr. Kai Goebel at NASA in the United States proposed a study whose main objective was to measure the battery discharge and predict the end of discharge considering the operating conditions for lithium ion batteries. To be precise, they purposed on employing a Bayesian Hierarchical Model (BHM)-based end of discharge prognostic for Li-ion batteries. Their work is currently published in the research journal, Reliability Engineering and System Safety.

The research technique employed entailed the utilization of two batteries with 16 discharge events with a simplified battery circuit model of the battery. Next, the research team examined the detailed discharge voltage profiles during different discharging cycles with variable load profiles. They then proceeded to demonstrate the BHM approach and group-level dependencies by utilizing more than one battery and more than one discharge cycle.

The authors observed that the BHM approach enabled inferences for both individual batteries and groups of batteries. The researchers then recorded the estimates of the hierarchical model parameters and the individual battery parameters after which their dependencies on load cycles were inferred. In addition, they noted that by using the BHM approach the predictions of end of discharge could be made accurately with a variable amount of battery data. Furthermore, this technique was seen to applicable even for new batteries without prior recorded data where the predictions were based only on the prior distributions describing the similarity within the group of batteries and their dependency on the load cycle.

In conclusion, the study presented a Bayesian hierarchical model (BHM)-based prognostics approach for Li-ion batteries, where the goal was to analyze and predict the discharge behavior of such batteries with variable load profiles and variable amounts of available discharge data. The results obtained showed that the technique could address cases with or without data. Altogether, the proposed method can capture additional relationships between parameters and use it to improve prognostics. Lastly, the BHM approach has been seen to permit inference at both the individual battery level and group of battery level.

Place, publisher, year, edition, pages
Ontario, CANADA: , 2018
Keywords
Significance, Prognostics, Hierarchical
National Category
Engineering and Technology Other Civil Engineering Probability Theory and Statistics
Research subject
Operation and Maintenance; Mathematical Statistics
Identifiers
urn:nbn:se:ltu:diva-70654 (URN)
Available from: 2018-08-30 Created: 2018-08-30 Last updated: 2019-04-23Bibliographically approved
Gustafsson, S., Sävenstedt, S., Martinsson, J. & Välivaara, B.-M. (2018). Need for reassurance in self-care of minor illnesses. Journal of Clinical Nursing, 27(5-6), 1183-1191
Open this publication in new window or tab >>Need for reassurance in self-care of minor illnesses
2018 (English)In: Journal of Clinical Nursing, ISSN 0962-1067, E-ISSN 1365-2702, Vol. 27, no 5-6, p. 1183-1191Article in journal (Refereed) Published
Abstract [en]

AIMS AND OBJECTIVES:

This study describes people's need for reassurance in self-care of minor illnesses.

BACKGROUND:

Self-care and active surveillance are advocated as important strategies to manage minor illnesses. Reassurance influences patient satisfaction and confidence in the practicing of self-care.

DESIGN:

This study is a descriptive and interpretive qualitative study.

METHODS:

Twelve persons with experience in self-care and receiving self-care advice were recruited, and data were collected using semi-structured interviews between September and December 2014. Data were analyzed using qualitative content analyses.

RESULTS:

Having previous experience and the ability to actively manage symptoms using self-care interventions was described as reassuring. Participants became stressed and concerned when the symptoms persisted and interventions lacked the desired effect, which often resulted in a decision to consult. Participants wanted to feel that the nurse was an actual person, who was sympathetic, present and understanding, when they received self-care advice. The nurse's assessment and reasoning of the symptoms facilitated care-seekers' assessments of risk, and clear and concrete advice on how to manage the symptoms exerted a calming effect. Patients needed to trust that the nurse understood their situation to embrace the advice, and being invited to return created a feeling that the nurse had listened and taken them seriously.

CONCLUSION:

Reassurance has the potential to allay doubts and fears to build confidence, which influences self-care and consultation behavior. Personal presence in the encounter, receiving an assessment and an explanation of the symptoms and precise advice are reassuring. This article is protected by copyright. All rights reserved.

Place, publisher, year, edition, pages
John Wiley & Sons, 2018
National Category
Nursing Probability Theory and Statistics
Research subject
Nursing; Matemathical Statistics
Identifiers
urn:nbn:se:ltu:diva-66572 (URN)10.1111/jocn.14157 (DOI)000428419400078 ()29119676 (PubMedID)
Note

Validerad;2018;Nivå 2;2018-04-10 (andbra)

Available from: 2017-11-13 Created: 2017-11-13 Last updated: 2018-04-27Bibliographically approved
Gustafsson, S., Martinsson, J., Välivaara, B.-M., Vikman, I. & Sävenstedt, S. (2016). Influence of self-care advice on patient satisfaction and healthcare utilization (ed.). Journal of Advanced Nursing, 72(8), 1789-1799
Open this publication in new window or tab >>Influence of self-care advice on patient satisfaction and healthcare utilization
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2016 (English)In: Journal of Advanced Nursing, ISSN 0309-2402, E-ISSN 1365-2648, Vol. 72, no 8, p. 1789-1799Article in journal (Refereed) Published
Abstract [en]

AimThe aim of this study is to explore the influence of nurse-led self-care advice on healthcare utilization and patients' satisfaction with telephone nursing.BackgroundMany consultations in high-cost settings are for conditions that are manageable through self-care and callers with greater satisfaction with the nurse interaction are nearly four times more likely to engage in self-care.DesignCross-sectional study.MethodsQuestionnaires were sent out to 500 randomly selected callers to the Swedish Healthcare Direct in Northern Sweden during March 2014. Callers were asked about their satisfaction with the consultation, their intended actions prior to consultation, the recommendation given by the nurse and the action undertaken after the call.ResultsYoung callers and persons recommended watchful waiting or recurrence if no improvements were significantly less satisfied with their care. When calling on their own behalf, both men and women rated the severity of their symptoms equally and were advised to self-care to the same extent. Self-care advice had a constricting influence on self-reported healthcare utilization, with 66·1% of cases resulting in a lower level of care than first intended. Feeling reassured after the call was the aspect of nursing care that influenced satisfaction the most.ConclusionReceiving self-care advice rather than referral to a general practitioner influences patient satisfaction negatively. Feeling reassured after consultation is strongly related to satisfaction, which in turn has been found to increase the likelihood of engaging in self-care behaviour.

National Category
Nursing Probability Theory and Statistics Physiotherapy
Research subject
Nursing; Matemathical Statistics; Physiotherapy
Identifiers
urn:nbn:se:ltu:diva-7453 (URN)10.1111/jan.12950 (DOI)000379932000007 ()27001441 (PubMedID)2-s2.0-85028243147 (Scopus ID)5d53ffb8-d712-4795-bf3f-07728a299db7 (Local ID)5d53ffb8-d712-4795-bf3f-07728a299db7 (Archive number)5d53ffb8-d712-4795-bf3f-07728a299db7 (OAI)
Note

Validerad; 2016; Nivå 2; 20160323 (andbra)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Gustafsson, S., Vikman, I., Sävenstedt, S. & Martinsson, J. (2015). Perceptions of needs related to the practice of self-care for minor illness (ed.). Paper presented at . Journal of Clinical Nursing, 24(21-22), 3255-3265
Open this publication in new window or tab >>Perceptions of needs related to the practice of self-care for minor illness
2015 (English)In: Journal of Clinical Nursing, ISSN 0962-1067, E-ISSN 1365-2702, Vol. 24, no 21-22, p. 3255-3265Article in journal (Refereed) Published
Abstract [en]

Aims and objectivesThe aim of this study was to describe people's perceptions of needs to feel confident in self-care for minor illnesses as well as their perceptions about supporting and obstructing factors in the practice of self-care.BackgroundMinor illness constitutes a large part of primary care, and patients' attendance to doctors' appointments for minor illness has been seen to increase future attendance for the same condition. Almost half of the consultations with telenurses result in the provision of self-care advice.DesignA cross-sectional survey.MethodPrimary data were collected using a questionnaire, and the study participants (n = 315) were randomly selected from the national Swedish address register.ResultsHaving knowledge and receiving health care advice and reliable information were perceived to be needs in order for participants to feel confident in self-care. Having family or friends to consult with was perceived to be a positive factor influencing confidence in self-care, especially for persons under the age of 35. Health care services were perceived to support self-care practice by offering easy access to care, giving information about self-care, and offering increased follow-up after consultations. Lack of knowledge, along with difficulties being away from work, were obstructing factors in the practice of self-care.ConclusionsYoung age was the factor influencing people's perceptions of needs and supporting factors the most. Young age and low knowledge scores about minor illnesses were the two factors that had the most influence on perceived obstructing factors.Relevance to clinical practiceNurses play a major role in the promotion of self-care and in the dissemination of self-care advice. If health care services fail to meet the needs of care-seekers with minor illnesses, patients might turn to out-of-hours clinics and emergency departments for help.

National Category
Nursing Physiotherapy Probability Theory and Statistics
Research subject
Nursing; Physiotherapy; Matemathical Statistics
Identifiers
urn:nbn:se:ltu:diva-5767 (URN)10.1111/jocn.12888 (DOI)000362907300023 ()26248528 (PubMedID)2-s2.0-84943659809 (Scopus ID)3f26b439-e69d-42d3-afca-e154a696e096 (Local ID)3f26b439-e69d-42d3-afca-e154a696e096 (Archive number)3f26b439-e69d-42d3-afca-e154a696e096 (OAI)
Note
Validerad; 2015; Nivå 2; 20150810 (andbra)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Carlson, J. E., Hägglund, F., Martinsson, J. & Saremi, A. (2009). Calibration of simulation models for ultrasonic transducers based on implicit calibration (ed.). In: (Ed.), (Ed.), 2008 IEEE Ultrasonics Symposium: IUS ; Beijing, China, 2 - 5 November 2008. Paper presented at IEEE International Ultrasonics Symposium : 02/11/2008 - 05/11/2008 (pp. 1528-1531). Piscataway, NJ: IEEE Communications Society
Open this publication in new window or tab >>Calibration of simulation models for ultrasonic transducers based on implicit calibration
2009 (English)In: 2008 IEEE Ultrasonics Symposium: IUS ; Beijing, China, 2 - 5 November 2008, Piscataway, NJ: IEEE Communications Society, 2009, p. 1528-1531Conference paper, Published paper (Refereed)
Abstract [en]

There are numerous software packages available for modeling of the sound pressure fields emitted by ultrasound transducers and transducer arrays. Accurate modeling of a real-world transducer requires knowledge of several parameters that are generally not known. This paper presents an estimation principle that can be used to calibrate such models, based on measurements of the sound field. The model separates the problem into estimation of the transducer's electro-mechanical impulse response and its spatial impulse response. The latter being what the software packages generally model. We demonstrate the principle with measurements of the sound field from a non-focused 5 MHz transducer. The results show that the modeled sound field agrees well with measurements.

Place, publisher, year, edition, pages
Piscataway, NJ: IEEE Communications Society, 2009
Series
I E E E International Ultrasonics Symposium. Proceedings, ISSN 1051-0117
National Category
Signal Processing
Research subject
Signal Processing
Identifiers
urn:nbn:se:ltu:diva-30770 (URN)10.1109/ULTSYM.2008.0372 (DOI)000268845800372 ()2-s2.0-67649335609 (Scopus ID)4b2f51e0-48d1-11dd-a9fb-000ea68e967b (Local ID)978-1-4244-2428-3 (ISBN)4b2f51e0-48d1-11dd-a9fb-000ea68e967b (Archive number)4b2f51e0-48d1-11dd-a9fb-000ea68e967b (OAI)
Conference
IEEE International Ultrasonics Symposium : 02/11/2008 - 05/11/2008
Note
Validerad; 2009; 20080703 (johanc)Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2018-07-10Bibliographically approved
Martinsson, J. (2009). Compensating distortion effects in repeated measurements under non-stationary conditions (ed.). Measurement science and technology, 20(2)
Open this publication in new window or tab >>Compensating distortion effects in repeated measurements under non-stationary conditions
2009 (English)In: Measurement science and technology, ISSN 0957-0233, E-ISSN 1361-6501, Vol. 20, no 2Article in journal (Refereed) Published
Abstract [en]

In this paper a compensation technique is presented for applications using repeated measurements under moderate non-stationary measurement conditions. The assumption is that the measurement conditions are stationary during a single repeated measurement but non-stationary over the entire measurement time. The objective with repeated measurements is often to retrieve an estimate of the (noise reduced) signal and its uncertainties. In order to obtain accurate estimates of these two quantities, stationary measurement conditions must be guaranteed under the measurement time. A condition that in many situations is difficult to achieve, e.g., during long measurement times or in a rapidly changing environment. The proposed method compensates for linear dynamic changes during the measurement time, where the dynamical changes, the underlying signal waveform and the noise covariance are considered unknown. The theoretical effect of moderate non-stationary conditions on repeated measurements is analyzed and experimentally validated. Estimation results using the proposed technique are presented for repeated ultrasonic measurements under non-stationary temperature conditions. The results show accurate signal estimation and noise characterization with uncorrelated normally distributed residuals, in contrast to standard synchronization techniques

National Category
Signal Processing
Research subject
Signal Processing
Identifiers
urn:nbn:se:ltu:diva-9026 (URN)10.1088/0957-0233/20/2/025103 (DOI)000262582500006 ()2-s2.0-63749121983 (Scopus ID)79634d20-c1e7-11dd-a054-000ea68e967b (Local ID)79634d20-c1e7-11dd-a054-000ea68e967b (Archive number)79634d20-c1e7-11dd-a054-000ea68e967b (OAI)
Note

Validerad; 2009; Bibliografisk uppgift: Paper id:: 025103; 20081204 (jesper)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-6289-4949

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