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  • 1.
    Abtahi, Farhad
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Aspects of Electrical Bioimpedance Spectrum Estimation2014Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Electrical bioimpedance spectroscopy (EBIS) has been used to assess the status or composition of various types of tissue, and examples of EBIS include body composition analysis (BCA) and tissue characterisation for skin cancer detection. EBIS is a non-invasive method that has the potential to provide a large amount of information for diagnosis or monitoring purposes, such as the monitoring of pulmonary oedema, i.e., fluid accumulation in the lungs. However, in many cases, systems based on EBIS have not become generally accepted in clinical practice. Possible reasons behind the low acceptance of EBIS could involve inaccurate models; artefacts, such as those from movements; measurement errors; and estimation errors. Previous thoracic EBIS measurements aimed at pulmonary oedema have shown some uncertainties in their results, making it difficult to produce trustworthy monitoring methods. The current research hypothesis was that these uncertainties mostly originate from estimation errors. In particular, time-varying behaviours of the thorax, e.g., respiratory and cardiac activity, can cause estimation errors, which make it tricky to detect the slowly varying behaviour of this system, i.e., pulmonary oedema.

    The aim of this thesis is to investigate potential sources of estimation error in transthoracic impedance spectroscopy (TIS) for pulmonary oedema detection and to propose methods to prevent or compensate for these errors.   This work is mainly focused on two aspects of impedance spectrum estimation: first, the problems associated with the delay between estimations of spectrum samples in the frequency-sweep technique and second, the influence of undersampling (a result of impedance estimation times) when estimating an EBIS spectrum. The delay between frequency sweeps can produce huge errors when analysing EBIS spectra, but its effect decreases with averaging or low-pass filtering, which is a common and simple method for monitoring the time-invariant behaviour of a system. The results show the importance of the undersampling effect as the main estimation error that can cause uncertainty in TIS measurements.  The best time for dealing with this error is during the design process, when the system can be designed to avoid this error or with the possibility to compensate for the error during analysis. A case study of monitoring pulmonary oedema is used to assess the effect of these two estimation errors. However, the results can be generalised to any case for identifying the slowly varying behaviour of physiological systems that also display higher frequency variations.  Finally, some suggestions for designing an EBIS measurement system and analysis methods to avoid or compensate for these estimation errors are discussed.

  • 2.
    Abtahi, Farhad
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Towards Heart Rate Variability Tools in P-Health: Pervasive, Preventive, Predictive and Personalized2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Heart rate variability (HRV) has received much attention lately. It has been shown that HRV can be used to monitor the autonomic nervous system and to detect autonomic dysfunction, especially vagal dysfunction. Reduced HRV is associated with several diseases and has also been suggested as a predictor of poor outcomes and sudden cardiac death. HRV is, however, not yet widely accepted as a clinical tool and is mostly used for research. Advances in neuroimmunity with an improved understanding of the link between the nervous and immune systems have opened a new potential arena for HRV applications. An example is when systemic inflammation and autoimmune disease are primarily caused by low vagal activity; it can be detected and prognosticated by reduced HRV. This thesis is the result of several technical development steps and exploratory research where HRV is applied as a prognostic diagnostic tool with preventive potential. The main objectives were 1) to develop an affordable tool for the effective analysis of HRV, 2) to study the correlation between HRV and pro-inflammatory markers and the potential degree of activity in the cholinergic anti-inflammatory pathway, and 3) to develop a biofeedback application intended for support of personal capability to increase the vagal activity as reflected in increased HRV. Written as a compilation thesis, the methodology and the results of each study are presented in each appended paper. In the thesis frame/summary chapter, a summary of each of the included papers is presented, grouped by topic and with their connections. The summary of the results shows that the developed tools may accurately register and properly analyse and potentially influence HRV through the designed biofeedback game. HRV can be used as a prognostic tool, not just in traditional healthcare with a focus on illness but also in wellness. By using these tools for the early detection of decreased HRV, prompt intervention may be possible, enabling the prevention of disease. Gamification and serious gaming is a potential platform to motivate people to follow a routine of exercise that might, through biofeedback, improve HRV and thereby health.

  • 3.
    Abtahi, Farhad
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems. Karolinska Institutet, Sweden.
    Hilderman, Marie
    Bruchfeld, Annette
    Seoane, Fernando
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems. University of Borås, Sweden.
    Janerot-Sjöberg, Birgitta
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging. Karolinska Institutet, Sweden.
    Lindecrantz, Kaj
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems. Karolinska Institutet, Sweden.
    Pro-inflammatory Blood Markers and Heart Rate Variability in Apnoea as a Reflection of Basal Vagal ToneManuscript (preprint) (Other academic)
    Abstract [en]

    Pro-inflammatory cytokines play a crucial role in inflammatory response, which istightly regulated by the nervous system to avoid the damage caused by inflammation. There isevidence for a cholinergic anti-inflammatory pathway that includes afferent and efferent vagalnerves that sense the inflammation and stimulate the anti-inflammatory response. Non-functionalanti-inflammatory response might lead to excessive and chronic inflammation e.g., rheumatoidarthritis (RA), inflammatory bowel disease (IBD), and poor outcome. Heart rate variability(HRV) has been proposed as a potential tool to monitor the level of anti-inflammatory activitythrough the monitoring of vagal activity. In this paper, the association of pro-inflammatorymarkers with HRV indices is evaluated. We used a database called “Heart Biomarker Evaluationin Apnea Treatment (HeartBEAT)” that consists of 6±2 hours of Electrocardiogram (ECG)recordings during nocturnal sleep from 318 patients at baseline and 301of them at 3 monthsfollow-up. HRV indices are calculated from ECG recordings of 5-360 minutes. The results showa statistically significant correlation between heart rate (HR) and pro-inflammatory cytokines,independent of duration of ECG analysis. HRV indices e.g., standard deviation of all RRintervals (SDNN) show an inverse relation to the pro-inflammatory cytokines. Longer ECGrecordings show a higher potential to reflect the level of anti-inflammatory response. In light oftheories for the cholinergic anti-inflammatory pathway, a combination of HR and HRV as areflection of basal vagal activity might be a potential prognostic tool for interventional guidance.

  • 4.
    Abtahi, Farhad
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Ji, Guangchao
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Lu, Ke
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Rödby, Kristian
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Björlin, Anders
    Kiwok AB.
    Östlund, Anders
    Kiwok AB.
    Seoane, Fernando
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems. Högskolan i Borås, Akademin för vård, arbetsliv och välfärd.
    Lindecrantz, Kaj
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Textile-Electronic Integration in Wearable Measurement Garments for Pervasive Healthcare Monitoring2015Conference paper (Other academic)
  • 5.
    Abtahi, Farhad
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Lu, Ke
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Dizon, M
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Johansson, M
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Seoane, Fernando
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems. Högskolan i Borås, Akademin för vård, arbetsliv och välfärd.
    Lindecrantz, Kaj
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Evaluation of Atrial Fibrillation Detection by using Heart Rate Variability analysis2015Conference paper (Other academic)
  • 6.
    Abtahi, Farhad
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Lu, Ke
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Guangchao, Li
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Rödby, Kristian
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Seoane, Fernando
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems. Högskolan i Borås.
    A Knitted Garment using Intarsia Technique for Heart Rate Variability Biofeedback: Evaluation of Initial Prototype.2015Conference paper (Other academic)
  • 7.
    Akay, Altug
    KTH, School of Technology and Health (STH), Health Systems Engineering, Systems Safety and Management.
    A Novel Method to Intelligently Mine Social Media to Assess Consumer Sentiment of Pharmaceutical Drugs2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis focuses on the development of novel data mining techniques that convert user interactions in social media networks into readable data that would benefit users, companies, and governments. The readable data can either warn of dangerous side effects of pharmaceutical drugs or improve intervention strategies. A weighted model enabled us to represent user activity in the network, that allowed us to reflect user sentiment of a pharmaceutical drug and/or service. The result is an accurate representation of user sentiment. This approach, when modified for specific diseases, drugs, and services, can enable rapid user feedback that can be converted into rapid responses from consumers to industry and government to withdraw possibly dangerous drugs and services from the market or improve said drugs and services.

    Our approach monitors social media networks in real-time, enabling government and industry to rapidly respond to consumer sentiment of pharmaceutical drugs and services.

  • 8.
    Almén, Lena
    KTH, School of Technology and Health (STH), Centres, Centre for Health and Building, CHB.
    Projekteringens möjligheter att minska risken för arbetsskador i byggproduktionen.: En fallstudie av säkerhetsstyrning i två byggprojekt.2009Report (Other academic)
    Abstract [sv]

    Sammanfattning

    Arbetsolycksfrekvensen bland bygg ‐ och anläggningsarbetare är högre, och pensionsåldern lägre, än genomsnittet i det svenska arbetslivet.

    Tidigare studier visar att projektörer har möjligheter att påverka arbetsmiljön i produktionen, ju tidigare i byggprocessen desto större är påverkansmöjligheterna.

    Enligt svensk lag har projektörer och byggherrar ansvar för arbetsmiljön i produktion. Den 1 januari 2009 skärptes Arbetsmiljölagen så att deras ansvar blev tydligare.

    Två byggprojekt, båda projekterade för januari 2009, studerades. I båda projekten var det en totalentreprenör som ansvarade för att projektera och producera flerbostadshus.

    Syftet med studien var att finna samband mellan arbetsmiljörisker i produktionen och beslut tagna under projekteringsskedet.

    Hantverkare och tjänstemän i produktionen identifierade riskfyllda arbetsmoment, vilka eventuellt hade varit möjliga att förebygga under projekteringsfasen. Fallen dokumenterades och presenterades för dem som hade deltagit i projekteringen av byggnaden. För vart och ett av fallen, ombads projektörerna att beskriva bakgrunden, vilka beslut som hade tagits och varför. I föreliggande rapport presenteras de riskfyllda arbetsmomenten och varför dessa uppstod. Analyser av fallen gjorde det möjligt att förstå vad projektörer kan göra för att förhindra arbetsskador i produktionen, och varför det ibland inte är möjligt.

    Studien visar att projektörer i många fall, inte var medvetna om arbetsmiljökonsekvenserna, och saknade rutiner för att identifiera, eliminera och hantera arbetsmiljörisker under projekteringsskedet. Krav från byggherre, lagar, stadsbyggnadskontor och bransch har begränsat projektörernas handlingsutrymme. Det har även funnits begränsningar vid inköp av produkter, på grund av svårigheter att få tag i produkter och material som är bra ur arbetsmiljösynpunkt samt restriktioner kopplade till avtal. Det har också varit problem med samordning och styrning av konsulter och underentreprenörer.

    Byggherren har ett viktigt ansvar för arbetsmiljön i byggprojekt. Det är av stor vikt att byggherren prioriterar säker arbetsmiljö genom hela byggprojektet, från det tidiga projekteringsskedet tills byggnaden är färdigställd.

    I varje skede av ett byggprojekt behövs rutiner för att samtliga aktörer ska beakta arbetsmiljökonsekvenser av sina beslut, parallellt med konsekvenser för produktivitet och produkt.

    För att åstadkomma förbättrad säkerhetsstyrning i byggprocessen, måste byggföretagen prioritera arbetsmiljöfrågan. Totalentreprenörer har, genom sitt ansvar för både projektering och produktion, goda möjligheter till arbetsmiljöstyrning. Det behövs rutiner för riskanalys i projekteringen, liksom på företagets olika avdelningar, och tillräcklig kompetens inom företaget. Centrala riktlinjer bör tas fram för att stimulera att erfarenheter och säkerhetsinsikter hos individer i hela produktionskedjan tas till vara inför framtida projekt.

    Projekteringens möjligheter att minska risken för arbetsskador i byggproduktionen 2009 6

    För att kunna identifiera, eliminera och hantera arbetsmiljörisker krävs både arbetsmiljökompetens och kompetens om produktionsmetoder. Kunniga hantverkare och tjänstemän från produktionen bör delta under projekteringen och i förberedelserna inför produktionsstart.

    Tillverkare av byggprodukter och byggelement behöver ta arbetsmiljöfrågan i beaktande i högre grad, för att utveckla produkter som är lätta att hantera och möjliga att montera utan risk för arbetsskada.

    Lagstiftningen har initierat förbättringar av säkerhetsstyrningen i byggprocessen. Genom användande av säkerhetsledningssystem kan det ske en ytterligare utveckling mot en säkrare arbetsmiljö i byggproduktionen. Riskfaktorerna som har identifierats i studien kan utgöra en grund för relevanta bedömningskriterier för intern och extern arbetsmiljörevision.

  • 9.
    Aronson, Eran
    KTH, School of Technology and Health (STH), Design, Work Environment, Safety and Health, DASH.
    Research Project: Lighting Häggvik Tunnel, Sollentuna2013Report (Other academic)
    Abstract [en]

    A reserch paper investigating the posibility of lowering light levels in tunnel while using LED's. Done with and for Trafikverket as part of an ongoing research regarding tunnel lighting.

  • 10.
    Aronson, Eran
    KTH, School of Technology and Health (STH).
    Visual adaptation for tunnel entrance2013Report (Other academic)
    Abstract [en]

    A research report done by the lighting laboratory at KTH STH for Trafikverket. The report is presenting a second stage of tunnel lighting research, focusing on the tunnel entrance zone, where improvements to existing recommendations are suggested.

  • 11. Aronsson, Gunnar
    et al.
    Eklund, Jörgen
    KTH, School of Technology and Health (STH), Ergonomics.
    Randle, Hanne
    Svensson, Lennart
    Inte bara här och nu utan också där och då: Reflektioner om arbetslivsforskningen och det stora hållbarhetsprojektet2009In: Arbetslivsforskning och hållbarhet: Arbetsliv i omvandling / [ed] I: Porsfelt, Växjö: Växjö universitet , 2009, 1Chapter in book (Other academic)
  • 12.
    Asplund, Maria
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Conjugated Polymers for Neural Interfaces: Prospects, possibilities and future challenges2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Within the field of neuroprosthetics the possibility to use implanted electrodes for communication with the nervous system is explored. Much effort is put into the material aspects of the electrode implant to increase charge injection capacity, suppress foreign body response and build micro sized electrode arrays allowing close contact with neurons. Conducting polymers, in particular poly(3,4-ethylene dioxythiophene) (PEDOT), have been suggested as materials highly interesting for such neural communication electrodes. The possibility to tailor the material both mechanically and biochemically to suit specific applications, is a substantial benefit with polymers when compared to metals. PEDOT also have hybrid charge transfer properties, including both electronic and ionic conduction, which allow for highly efficient charge injection.

     

    Part of this thesis describes a method of tailoring PEDOT through exchanging the counter ion used in electropolymerisation process. Commonly used surfactants can thereby be excluded and instead, different biomolecules can be incorporated into the polymer. The electrochemical characteristics of the polymer film depend on the ion. PEDOT electropolymerised with heparin was here determined to have the most advantageous properties. In vitro methods were applied to confirm non-cytotoxicity of the formed PEDOT:biomolecular composites. In addition, biocompatibility was affirmed for PEDOT:heparin by evaluation of inflammatory response and neuron density when implanted in rodent cortex.

     

    One advantage with PEDOT often stated, is its high stability compared to other conducting polymers. A battery of tests simulating the biological environment was therefore applied to investigate this stability, and especially the influence of the incorporated heparin. These tests showed that there was a decline in the electroactivity of PEDOT over time. This also applied in phosphate buffered saline at body temperature and in the absence of other stressors. The time course of degradation also differed depending on whether the counter ion was the surfactant polystyrene sulphonate or heparin, with a slightly better stability for the former.

     

    One possibility with PEDOT, often overlooked for biological applications, is the use of its semi conducting properties in order to include logic functions in the implant. This thesis presents the concept of using PEDOT electrochemical transistors to construct textile electrode arrays with in-built multiplexing. Using the electrolyte mediated interaction between adjacent PEDOT coated fibres to switch the polymer coat between conducting and non conducting states, then transistor function can be included in the conducting textile. Analogue circuit simulations based on experimentally found transistor characteristics proved the feasibility of these textile arrays. Developments of better polymer coatings, electrolytes and encapsulation techniques for this technology, were also identified to be essential steps in order to make these devices truly useful.

     

    In summary, this work shows the potential of PEDOT to improve neural interfaces in several ways. Some weaknesses of the polymer and the polymer electronics are presented and this, together with the epidemiological data, should point in the direction for future studies within this field.

  • 13.
    Atefi, Seyed Reza
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Electrical Bioimpedance Cerebral Monitoring: From Hypothesis and Simulation to First Experimental Evidence in Stroke Patients2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Stroke is amongthe leading causes of death worldwide and requires immediate care to prevent death or permanent disability. Unfortunately, the current stateof stroke diagnosis is limited to fixed neuroimaging facilities that do not allow rapid stroke diagnosis. Hence, a portable stroke-diagnosis device could assist in the pre-hospital triage of patients. Moreover, such a portable device could also be useful for bedside stroke monitoring of patients in the Neuro Intensive Care Unit (Neuro-ICU) to avoid unnecessary neuroimaging. Recent animal studies and numerical simulations have supported the idea of implementing Electrical Bioimpedance (EBI) in a portable device, allowing non-invasive assessment as a useful tool for the pre-hospital triage of stroke and Traumatic Brain Injury (TBI) patients. Unfortunately, these studies have not reported any results from human subjects in the acute phase of the stroke. The numerical simulations are also based on simple models that sometimes lack necessary details.

    Finite Element Method (FEM) simulations on a realistic numerical head model as well as experimental Bioimpedance Spectroscopy (BIS) measurements from human subjectsin the acute, subacute and chronic phasesof stroke were used to answer the following research questions: (i) Does stroke modify the electrical properties of brain tissue in a way that is detectable via EBI? (ii) Would it be possible to detect stroke via EBI as early as in the acute and sub-acute phase?(iii) Is EBI sensitive enough to monitor changes caused by stroke pathogenesis?

    Using FEM to simulate electrical current injection on the head and study the resulting distribution of electrical potential on the scalp, it was shown that Intra-Cranial Hemorrhage (ICH) affects the quasi-symmetric scalp potential distribution,creating larger left-right potential asymmetry when compared to the healthy head model. Proof-of-concept FEM simulations were also tested in a small cohort of 6ICH patients and 10 healthy controls, showing that the left-right potential difference in the patients is significantly (p<0.05) larger than in the controls. Using bioimpedance measurements in the acute,  subacute and chronic phasesof stroke and examining simple features, it was also shown that the head EBI measurements of patients suffering stroke are different from controls, enabling the discrimination of healthy controls and stroke patients at any stage of the stroke. The absolute change in test-retest resistance measurements of the control group (~5.33%) was also found to be significantly (p<0.05) smaller than the EBI measurements of patients obtained 24 hours and 72 hours after stroke onset (20.44%). These results suggested that scalp EBI is sensitive to stroke pathogenesis changesand thususeful for bedside monitoring in the Neuro-ICU. These results suggested that EBI is a potentially useful tool for stroke diagnosis and monitoring.

    Finally, the initial observations based on a small number of patients, addressing the proposed future work of this thesis, suggested that the average head resistance amplitude of hemorrhagic stroke patients is smaller than in healthy controls, while ischemic stroke patients show a larger resistance amplitude than the controls. Scalp potential asymmetry analysis of healthy, hemorrhagic and ischemic stroke subjects also suggests that these three groups can be separated. However, these results are based on a small number of patients and need to be validated using a larger cohort. Initial observations also showed that the resistance of the EBI measurements of controls is robust between test and retest measurements, showing no significant difference (less than 2% and p>0.05). Subject position during EBI recording (supine or sitting) did not seem to affect the resistance of the EBI measurements (p>0.05). However, age, sex and head size showed significant effects on the resistance measurements. These initial observations are encouraging for further research on EBI for cerebral monitoring and stroke diagnosis. However, at this stage, considering the uncertainties in stroke type differentiation, EBI cannot replace CT but has the potential to be used as a consultation tool.

  • 14.
    Ayas, Ebru
    KTH, School of Technology and Health (STH), Ergonomics.
    Engineering Quality Feelings: Applications in products, service environments and work systems2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Contemporary quality issues in product design are moving from materialistic to emotional user fulfillment; comprehensive research is needed to examine quality product feelings. This research is directed toward a deeper understanding of user and customer quality feelings for different product types, including services.

    The quality feelings concept includes dimensions of product quality, especially functionality, ergonomics and aesthetics. The first objective of this thesis is to identify, prioritize and synthesize quality feelings into product attributes in product development applications. The second objective is to explore, test and propose methodological approaches for designing quality feelings into products.

    Several methods from psychology, ergonomics, statistics and probabilistic methods and heuristics were applied to achieve the objectives. From a methodological viewpoint, Likert scales, free elicitation technique and Just About Right scales were applied for data collection. Multiple Regression, Factor Analysis, Correspondence Analysis, Genetic algorithms, Partial Least Squares (PLS) and Rough Sets (RS) were applied for data analyses. For ergonomic product evaluations, direct observations, 3D workload simulations, time and frequency analyses were conducted.

    Five product applications are included in this thesis: operator driver cabin design of reach trucks, steering wheel design trigger switch design in right-angled nutrunners, bed-making systemsproducts and waiting room environments.

    Heuristic methods were found effective when there is a high number of product attributes that interact to provide quality feelings. RS results are consistent with PLS attribute predictions. When the number of product attributes is large in comparison to the number of observations, PLS extracts informative results for quality feelings. The RS method is effective in identifying interactions among design attributes.

    Quality feelings are associated with both tangible (tactile characteristics) and intangible (quick and easy to use) product characteristics. Words such as safety, functionality, ergonomics, comfort, reliability, supportiveness, usability, feedback, pleasantness, attractiveness, durability and distinctiveness describe quality feelings from tangible products and services. Based on product type, the quality dimensions represented by these words possess different interactions and dependencies. In work environments, products act as prostheses between workers for social interaction, which need to be considered as important quality feelings dimensions.

  • 15.
    Ayas, Ebru
    et al.
    KTH, School of Technology and Health (STH), Ergonomics.
    Eklund, Jörgen
    KTH, School of Technology and Health (STH), Ergonomics.
    An Affective Engineering Assessment of a Hospital Bedding System Innovation2011In: Applied Ergonomics, ISSN 0003-6870, E-ISSN 1872-9126Article in journal (Other academic)
    Abstract [en]

    Developing bedding products requires consideration of human-product interactions such as usability and quality aspects besides ergonomics and productivity. Previous studies focus on finding associations between discomfort evaluations and physiological measurements of conventional bedding. The purpose of this study is to assess a new bedding system by observing affective and discomfort perceptions, physical loads, and time usage by nursing personnel. Fourteen nursese valuated a conventional and a new bedding system. Results suggest that nurses’ quality perceptions and overall experiences with the new bedding were positive. Considering physical loads the average time and frequency of bending forward were significantly lower for the new bedding versus conventional bedding. The time analysis yielded significant improvements to make a bed with the new bedmaking system. Quality perceptions were associated with tactile qualities (e.g. soft, nice to touch, etc.) and applicability (e.g. quick setup) for both bedmaking systems.

  • 16.
    Ayas, Ebru
    et al.
    KTH, School of Technology and Health (STH), Ergonomics.
    Eklund, Jörgen
    KTH, School of Technology and Health (STH), Ergonomics.
    Ishihara, Shigekazu
    Affective engineering evaluation of non-linear trigger switch mechanisms2011In: Applied Ergonomics, ISSN 0003-6870, E-ISSN 1872-9126Article in journal (Other academic)
    Abstract [en]

    The trigger switch mechanisms of nutrunners are important for operators to perceive feedback while tightening bolt joints. Previous studies focus on associations between discomfort evaluations and powered tool operation. This paper addresses how operator preferences are linked with functionality requirements from trigger switch mechanisms. Subjects evaluated five switch mechanism prototypes regarding perceptions of quality, feedback, firmness, and distinctness. Results suggest that loading and unloading phases of trigger operation are significant predictors of perceptions of quality. The trigger switch mechanism with a combination of high peak-drop-bottom forces was perceived with better quality, feedback, and distinctness in comparison to the other mechanisms. The study also revealed that when the switch mechanism was designed to give more distinctness and feedback, higher quality is perceived.

  • 17.
    Bergholm, Fredrik
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering.
    Hamid Muhammed, Hamed
    KTH, School of Technology and Health (STH), Medical Engineering.
    Larsolle, A.
    Acquiring instantaneous multispectral imagery using a single image sensor with multiple filter mosaic2007Conference paper (Other academic)
  • 18.
    Berglund, Martina
    KTH, School of Technology and Health (STH), Ergonomics.
    Using Tentacles in Planning and Scheduling Work: Activities, Roles and Contributions2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Handling production scheduling is increasingly difficult for manyenterprises, and human involvement is necessary. The overall objective ofthis research was to gain further understanding of planners’ and schedulers’work within the manufacturing industry, to elucidate how their worksituation is formed, and to explain their significance to other employees’work and company activities. Scheduling work was studied in fourcompanies in the Swedish woodworking industry; a sawmill, a parquet floormanufacturer, a furniture manufacturer and a house manufacturer. Themethod used was activity analysis which is based on the analysis of workactivities in real work situations. Data collection included 20 days’observations and 65 interviews. Cross-case analysis with British cases onplanning work was also included.The findings revealed that the schedulers’ tasks lead to many activities. Twothirds of these are what can be expected. The remaining third constitutesactivities that depend on the schedulers’ individual attributes and the contextin which they work. The schedulers serve as problem solvers in a number ofdomains and constitute efficient information nodes, making them animportant service function. Furthermore, they have an alignment rolebetween different organizational groups. This role is specifically remarkablein dealing with production enquiries that must be aligned with productioncapability. Here, both planners and schedulers play an essential role inlinking the manufacturing and the commercial sides and their differentfunctional logics.Planners and schedulers in daily work exert strong influence on others. Theydo not hold legitimate power. Instead their influence emanates mainly fromaccess to and control of information and their ability to apply expertise tointerpret this information and examine the impact of decisions made acrossdifferent areas of the business. Personal power related to social skills is alsosignificant.Furthermore, they facilitate others’ work in continuous personalinteractions, serving the technical scheduling software system, and aligningdifferent organizational functions. In combination with expert knowledgeand developed social skills, they significantly contribute to quality operationsperformance. Finally, the schedulers influence the decision latitude of otheremployees and may indirectly promote job satisfaction, thus contributing todeveloping appropriate working conditions for others in the company.

  • 19.
    Berglund, Martina
    et al.
    KTH, School of Technology and Health (STH), Ergonomics.
    Guinery, Jane
    Production planning aligning customer requests with production capabilityManuscript (preprint) (Other academic)
  • 20.
    Brännmark, Mikael
    KTH, School of Technology and Health (STH), Ergonomics.
    Implementering av Lean i medelstora företag: En lärande utvärdering om hållbarutveckling2010Report (Other academic)
    Abstract [sv]

    Denna rapport är ett av delresultaten från det interaktiva forskningsprojektet Produktionslyftet, inom HELIX VINN Excellence Centre. Projektet genomförs i samarbete med Produktionslyftet, ett nationellt program för spridande av managementkonceptet Lean produktion. Syftet med forskningsprojektet är att öka kunskapen om hur hållbart utvecklingsarbete kan bedrivas, både utifrån ett program- och företagsperspektiv.

    Rapporten beskriver två delstudier, en kvalitativ och en kvantitativ, som genomförts i samarbete med elva av företagen i Produktionslyftet, tio av dem pilotföretag för programmet. Den första delstudien genomfördes under sommaren 2008, genom en intervjustudie med programmets pilotföretag, medan den andra genomfördes under våren 2009, i formen av en enkätstudie med sju av företagen i programmet. Då en interaktiv forskningsansats har använts, så har i båda fallen den insamlade empirin från de båda delstudierna återkopplats till representanter från Produktionslyftet, samt programmets finansiärer, och en gemensam tolkning och analys av empirin har gjorts. Denna gemensamma tolkning har sedan analyserats utifrån modeller kring hållbart utvecklingsarbete och resultatet från detta arbete har sedan sammanfattats i två arbetsrapporter, som har återkopplats till programmet och dess finansiärer.

    Resultaten i delstudierna, samt den gemensamma tolkningen och analysen av empirin, fokuserar Produktionslyftets coacher, samt deras arbete med företagen. Dels spelar coacherna uppenbarligen en central roll i programmets arbete med företagen, och dels är coacherna mycket uppskattade av företagen. Coachernas arbetssätt, samt hur deras arbete påverkar möjligheten för företagen att skapa en hållbar utveckling, upptar också en central del i rapporten. Detta kan sammanfattas, som att om coacherna driver på arbetet för hårt, få finns det risk att det uppstår problem för företagen, men om coacherna inte är pådrivande så finns risken att åtminstone vissa av företagen inte tar sitt ansvar för Lean-arbetet. Med andra ord, coachernas arbete med företagen utgör en svår balansgång mellan att uppfylla företagens målsättningar med Lean-arbetet, i vägning mot Produktionslyftets mål och syfte. Men resultaten pekar också på vikten av att företagen har ett tydligt ägarskap och driv i utvecklingsarbetet.

    Slutsatsen i denna rapport blir därför att om programmets utvecklingsarbete skall bli hållbart, så hänger det troligen på dels att man har duktiga och kompetenta coacher, men också att man har en väl fungerande företagsrekryteringsprocess, där företag med ett internt driv för Lean-arbetet väljs till programmet.

  • 21.
    Brännmark, Mikael
    et al.
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    Eklund, Jörgen
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    Leaninspirerade förändringar och personalens upplevelser2013In: Lean i arbetslivet / [ed] Sederblad, Per, Stockholm: Liber, 2013, 1, 103-121 p.Chapter in book (Other academic)
    Abstract [sv]

    De anställdas upplevelser av hur de kommer att påverkas av ett förändringskoncept är en avgörande faktor för om konceptet kommer att få reellt genomslag eller inte. Det här kapitlet behandlar denna centrala aspekt av leankonceptet – hur personalen upplever leaninspirerade förändringar. Just denna fråga finns det mycket lite empirisk forskning kring, så väl internationellt som i Sverige.

    I kapitlet redovisas en studie av personalens erfarenheter från leanarbetet i medelstora svenska tillverkningsföretag som ingått i det nationella programmet Produktionslyftet. Programmet kan ses som ett exempel på en ”svensk tolkning” av lean. Produktionslyftet har fått stort genomslag i den svenska diskussionen om lean, men samtidigt har konsekvenserna av lean ur ett arbetsmiljöperspektiv inte utvärderats på ett genomgripande sätt.

  • 22.
    Brännmark, Mikael
    et al.
    KTH, School of Technology and Health (STH), Ergonomics.
    Eklund, Jörgen
    KTH, School of Technology and Health (STH), Ergonomics.
    Håkansson, Malin
    KTH, School of Technology and Health (STH), Ergonomics.
    Vogel, Kjerstin
    KTH, School of Technology and Health (STH), Ergonomics.
    Belastningsergonomiska studier utifrån ett produktions- och systemperspektiv: Kunskapsöversikt2012Report (Other academic)
  • 23.
    Buendia, Ruben
    KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS).
    Improvements in Bioimpedance SpectroscopyData Analysis: Artefact Correction, ColeParameters, and Body Fluid Estimation2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The estimation of body fluids is a useful and common practice in the status assessment of diseasemechanisms and treatments. Electrical bioimpedance spectroscopy (EBIS) methods are non-invasive,inexpensive, and efficient alternatives for the estimation of body fluids. However, these methods areindirect, and their robustness and validity are unclear.Regarding the recording of measurements, a controversy developed regarding a spectrum deviationin the impedance plane, which is caused by capacitive leakage. This deviation is frequentlycompensated for by the extended Cole model, which lacks a theoretical basis; however, there is nomethod published to estimate the parameters. In this thesis, a simplified model to correct thedeviation was proposed and tested. The model consists of an equivalent capacitance in parallel withthe load.Subsequently, two other measurement artefacts were considered. Both artefacts were frequentlydisregarded with regard to total body and segmental EBIS measurements as their influence isinsignificant with suitable skin-electrode contact. However, this case is not always valid, particularlyfrom a textile-enabled measurement system perspective. In the estimation of body fluids, EBIS dataare fitted to a model to obtain resistances at low and high frequencies. These resistances can berelated to body fluid volumes. In order to minimise the influence of all three artefacts on theestimation of body fluids and improve the robustness and suitability of the model fitting the differentdomains of immittance were used and tested. The conductance in a reduced frequency spectrum wasproposed as the most robust domain against the artefacts considered.The robustness and accuracy of the method did not increase, even though resistances at low and highfrequencies can be robustly estimated against measurement artefacts. Thus, there is likely error in therelation between the resistances and volumes. Based on a theoretical analysis, state of the artmethods were reviewed and their limitations were identified. New methods were also proposed. Allmethods were tested using a clinical database of patients involved in growth hormone replacementtherapy. The results indicated EBIS are accurate methods to estimate body fluids, however they haverobustness limits. It is hypothesized that those limits in extra-cellular fluid are primarily due toanisotropy, in total body fluid they are primarily due to the uncertainty ρi, and errors in intra-cellularfluid are primarily due to the addition of errors in extracellular and total body fluid. Currently, theseerrors cannot be prevented or minimised. Thus, the limitations for robustness must be predicted priorto applying EBIS to estimate body fluids.

  • 24.
    Buendia, Ruben
    et al.
    KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS).
    Seoane, Fernando
    KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS).
    Bosacus, I.
    University of Gothenburg.
    Gil-Pita, Roberto
    Department of Theory of the Signal and Communications, University of Alcala, Madrid, Spain.
    Johannsson, G.
    Ellegård, L.
    Lindecrantz, Kaj
    KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS).
    Robust approach against capacitive coupling for the estimation of body fluids using clinical bioimpedance spectroscopy measurementsManuscript (preprint) (Other academic)
  • 25.
    Buendía López, Rubén
    KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS).
    Model Based Enhancement of Bioimpedance Spectroscopy Analysis: Towards Textile Enabled Applications2011Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Several signal processing approaches have been developed to overcome the effect of stray capacitances in Electrical Bioimpedance Spectroscopy (EBIS) measurements. EBIS measurements obtained with textile-enabled instrumentation are more vulnerable to stray capacitances. Currently, the most widespread approach for correcting the effect of stray capacitances in EBIS is the time delay (

    Td) compensation method, which also has several drawbacks. In this study, the Td method is revisited and its limitations and its lack of a scientific basis are demonstrated. To determine better ways to overcome the effect of stray capacitances, a simplified measurement model is proposed that is based on previous models of artefacts in EBIS measurements described in the literature. The model consists of a current divider with a parasitic capacitance (Cpar) in parallel with the load. Cpar creates a pathway for the measurement current to leak away from the load, provoking a capacitive leakage effect. In this thesis, three approaches with different limitations are proposed to overcome the capacitive leakage effect. The first approach estimates Cpar and subtracts it from the measurements, thus finding the load. Cpar can be estimated because the susceptance of biological tissue is null at infinite frequency. Therefore, at high frequencies, the susceptance of the tissue can be neglected, and the slope of the susceptance of the measurement is Cpar. The accuracy of Cpar depends on the maximum frequency measured and the value of Cpar. Therefore, it may not be possible to accurately estimate small values of Cpar in the typical frequency ranges used in EBIS. The second and third approaches use the Cole fitting process to estimate the Cole parameters, which form the basis for most EBIS applications. Because the conductance of the measurement is free from the effect of Cpar, performing Cole fitting on the conductance avoids the effect of Cpar in the fitting process. With a poor skin-electrode contact, this approach may not be sufficiently accurate. The third approach would be to perform the Cole fitting on the modulus with a reduced upper frequency limit because the modulus and the low-medium frequencies are very robust against the effect of artefacts. In this approach, a slight capacitive leakage effect is unavoidable. Since it is common to find tainted measurements, especially among those obtained with textile-enabled instrumentation, it is important to find viable methods to avoid their effect. The three methods studied showed that they could reduce the effect of tainted measurements.

  • 26.
    Carlsson-Kanyama, Annika
    et al.
    KTH, School of Technology and Health (STH), Centres, Centre for Health and Building, CHB.
    Thunqvist, Eva-Lotta
    KTH, School of Technology and Health (STH), Centres, Centre for Health and Building, CHB. KTH, School of Technology and Health (STH), Health Systems Engineering.
    Larsson, Tore J
    KTH, School of Technology and Health (STH), Centres, Centre for Health and Building, CHB.
    Odla under tak i eller nära bostaden2014Report (Other academic)
    Abstract [en]

    Within a project called “The sustainable greenhouse as a complement to buildings” financed by the Delegation of sustainable cities in Sweden, researchers, consultants and students have during 2013 developed, tested and evaluated various solutions for cultivating under roofs in or close to dwellings. We included solutions such as cultivating a plot in a rooftop greenhouse, a circular cultivation balcony or to cultivate in one’s kitchen or living room using a fish and vegetable furniture, a green wall, a green lamp or a green frame attached to the wall. The practical trials were preceded by a literature survey that described good examples of cultivation under roofs in various cities around the world.The results show that here are many inspiring examples of cultivating under roofs in cities and that such cultivation has gained some momentum. Our practical trials show among others that urban agriculture seems challenging and appealing for many but that the solutions that we have tested seem to be too expensive and partly also too time-consuming. Those who like to cultivate do so because it is fun and they can get products of good quality. To lessen the environmental impacts are also a reason but here our results that productivity in urban farming has to be higher than in our trials in order for the products to be considered as “climate-friendly”. Growing fish at home showed to be rather unpopular and many thought that slaughtering the fish by themselves would be nasty. Others results from the project are a water cooled LED lamp built in four copies and successfully installed in a fish and vegetable production unit as well as drawings and costs estimates for a cultivation bench.Proposals for further studies include analysis of flight and nutrient requirements for cultivation under roofs in cities as well as measurements of productivity. More low cost solutions for cultivating under glass should also be developed. To expand and maintain interest and knowledge for cultivation under roofs in cities is not only important for increasing social sustainability and eventually the environmental one as well but also because of the need to enhance preparedness.

  • 27.
    Cheng, Kimberley
    KTH, School of Technology and Health (STH), Structural Biotechnology.
    Single-particle cryo-electron microscopy of macromolecular assemblies2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In this thesis, single-particle cryo-electron microscopy (cryo-EM) was used to study the structure of three macromolecular assemblies: the two hemocyanin isoforms from Rapana thomasiana, the Pyrococcus furiosus chaperonin, and the ribosome from Escherichia coli.

    Hemocyanins are large respiratory proteins in arthropods and molluscs. Most molluscan hemocyanins exist as two distinct isoforms composed of related polypeptides. In most species the two isoforms differ in terms of their oligomeric stability, and thus we set out to investigate the two Rapana thomasiana hemocyanins (RtH) in order to explain this behaviour. Our findings showed that the two RtHio forms are identical at the experimental resolution. Furthermore, three previously unreported connections that most likely contribute to the oligomeric stability were identified.

    Chaperonins are double-ring protein complexes that assist the folding process of nascent, non-native polypeptide chains. The chaperonin from the hyperthermophilic archaea Pyrococcus furiosus belongs to Group II chaperonins, and unlike most othergroup II chaperonins it appears to be homo-oligomeric. The 3D reconstruction of the Pyrococcus furiousus chaperonin revealed a di-octameric structure in a partially closed/open state, something in between the closed folding-active state and the open substrate-accepting state.

    The ribosome is the molecular machine where protein synthesis takes place. In bacteria there is a unique RNA molecule called transfer-messenger RNA (tmRNA) that together with its helper protein SmpB rescues ribosomes trapped on defective messenger RNAs (mRNAs) through a process called trans-translation. tmRNA is about 4 times the size of a normal tRNA, and it is composed of a tRNA-like domain (TLD) that is connected to the mRNA-like domain (MLD) by several pseudoknots (PKs) and RNA helices. During trans-translation, tmRNA utilize its TLD to receive the incomplete polypeptide from the peptidyl-tRNA in the ribosomal P site of the stalledribosome. Subsequently, its MLD is used to tag the incomplete polypeptide with adegradation signal. When tmRNA enters a stalled ribosome the MLD and pseudoknots form a highly structured arc that encircles the beak of the small ribosomal subunit. Byutilizing maximum-likelihood based methods for heterogeneity analysis we could observe the Escherichia coli ribosome in a number of different tmRNA·SmpB-boundstates. The cryo-EM map of the post-accommodated state revealed that the TLD·SmpBpart of the tmRNA·SmpB complex mimics native tRNAs in the A site of stalled ribosomes. The density map also showed that the tmRNA arc remains well structuredand that it is still attached to the beak of the small ribosomal subunit. Thereconstructions of the double-translocation tmRNA-bound ribosome complex showed that the pseudoknots of tmRNA still form an arc, and that they are located at positions similar to the ones assigned for the pseudoknots in the post-accommodated state. In addition, the tmRNA arc exists in two states; one stable and highly structured and another more flexible and disorganized.

  • 28.
    Cheng, Kimberley
    et al.
    KTH, School of Technology and Health (STH), Structural Biotechnology.
    Ivanova, Natalia
    Biomedicinskt centrum, Uppsala.
    Scheres, S.H.W
    Pavlov, Michael
    Biomedicinskt centrum.
    Carazo, J.M.
    Herbert, Heinz
    Ehrenberg, Måns
    Lindahl, Martin
    KTH, School of Technology and Health (STH).
    Structural analysis of double translocated tmRNA on the 70S ribosome indicates flexibility of the tmRNA structure.Manuscript (preprint) (Other academic)
  • 29.
    Cheng, Kimberley
    et al.
    KTH, School of Technology and Health (STH), Structural Biotechnology (Closed 20130701).
    Karlström, M
    Purhonen, P
    Ladenstein, R.
    Herbert, Hans
    Koeck, Philip J.B.
    Low resolution structure and apparent melting temperature of the chaperonin from Pyrococcus furiosusManuscript (preprint) (Other academic)
  • 30.
    Danielsson, Christina
    KTH, School of Technology and Health (STH), Design, Work Environment, Safety and Health, DASH.
    Office Environment and Employee Satisfaction: The Impact of Office-type.Manuscript (Other academic)
  • 31.
    Danielsson, Christina
    KTH, School of Technology and Health (STH).
    Office environment, health and job satisfaction: an explorative study of office design's influence2005Licentiate thesis, comprehensive summary (Other scientific)
    Abstract [en]

    The present thesis investigates environmental factors impact on office employees. More specifically, it investigates: 1) perception and experience of office environments, 2) satisfaction with office environments, and 3) health status and job satisfaction in connection to office environment. It is based on an empirical study with 491 office employees from twenty-six companies and divisions in larger companies. Each one respectively represents one of seven identified office-types in office design: cell-office, sharedroom office, small open plan office, medium open plan office, large open plan office, flex-office and combi-office. This study takes its basis in architecture, although an interdisciplinary approach from organizational and management theory, environmental psychology, and social and stress medicine has been used. Qualitative and quantitative methods were used.

    In Article I a review of the different research fields that investigate environmental influences are presented with a focus on office environments. Different perspectives on the environmental impact on office employees are investigated.

    In Article II an analysis of office environment based on the employee’s perception and experience of the architecture is done based on in-depth interviews using a method originally developed by Kevin Lynch (1960). The method measures the "imagebility" of a space, rated by the users with following elements: landmark, node, path, edge and district. The result showed that the method, based on employees’ perception and use of space, is a possible tool in the design process to get a better understanding of where the elements that reinforce "imageability" most likely will appear in an office environment. The method thus gives a better idea of the future "imageability" of a space and could be useful as guidance in the design process of how the architectural design will be received by the users in the end.

    In Article III employees’ satisfaction with the office environment in different office-types is investigated. The article focuses on three domains: 1) Ambient factors, 2) Noise and Privacy and 3) Designrelated factors. The statistical analysis was done using a logistic regression model with multivariate analysis. Adjustment was done for: age, gender, job rank, job satisfaction and market division. The results show differences in satisfaction with the office environment between employees in different office-types, many of which were statistically significant. When differences persist in the multivariate analysis they can possibly be ascribed to the office-type. Results show that employees in cell-offices are prominently most satisfied followed by those in flex-offices. Cell-offices rate only low on social aspects of Design-related factors. A major finding is internal differences between different office-types where employees share workspace and facilities. The medium and large open plan offices could be described as high-risk officetypes.

    In Article IV differences between employees in different office-types with regard to health, wellbeing and job satisfaction are analyzed. A multivariate analysis of the data was done with adjustment for the confounders: age, gender, job rank and market division. The results show that there are risks of ill health and poor well-being in medium and small open plan offices. Employees in these office-types show significantly higher risks compared with those in other office-types. In medium open plan and combioffices the employees show the highest prevalence of low job satisfaction. The best chance for good health status and job satisfaction is among employees in cell-offices and flex-offices; there are, however, internal differences in distribution on different outcome variables for job satisfaction. The major finding of these studies is that there are significant differences with regard to satisfaction with office environments as well as health status and job satisfaction between employees in different office-types; differences that can possibly can be ascribed to the office-types as they persist after adjustment for important confounders.

  • 32.
    Danielsson, Christina
    KTH, School of Technology and Health (STH).
    Three Approaches to Office Design; A Review of Environmental InfluencesManuscript (Other academic)
  • 33.
    Ekberg, K
    et al.
    Linköpings Universitet.
    Gustavsson, M
    Linköpings Universitet.
    Lundqvist, D
    Linköpings Universitet.
    Reineholm, C
    Linköpings Universitet.
    Fagerlind, A-C
    Linköpings Universitet.
    Karlsson, N
    Linköpings Universitet.
    Eklund, Jörgen
    KTH, School of Technology and Health (STH), Ergonomics.
    Leading and organising for health and productivity2012In: Book of Proceedings: Zürich 2012 10th Conference, European Academy of Occupational Health Psychology, 2012Conference paper (Other academic)
  • 34.
    Eklund, Jörgen
    KTH, School of Technology and Health (STH), Ergonomics.
    Improvements, innovation and Lean2012Conference paper (Other academic)
    Abstract [en]

    Lean has become a dominating change concept in Sweden and in other countries. It has been discussed whether Lean is a support or an obstacle for improvement and innovation. The aim of this paper is to identify examples, opportunities and obstacles for improvement and innovation within the framework of Lean. Cases from 30 organizations have been analyzed. The empirical examples and also literature show that it is possible to work with Lean or Lean principles in a way that arenas of innovation and improvement are created, but that in other organizations this does not happen.

  • 35.
    Eklund, Jörgen
    KTH, School of Technology and Health (STH), Ergonomics.
    Intervention ergonomique et recherché interactive: Les journees de Bordeaux sur la pratique de lérgonomie2009In: Diversite des domains díntervention, nouvelles pratiques de lérgonomie: Quávons-nous encore en commun?, Bordeaux: Université Victor Segalen , 2009, 97-101 p.Chapter in book (Other academic)
  • 36.
    Eklund, Jörgen
    et al.
    KTH, School of Technology and Health (STH), Ergonomics.
    Rose, Linda
    KTH, School of Technology and Health (STH), Ergonomics.
    A network organisation supporting innovative product design2009In: Organising Work for Innovation and Growth: Experiences and efforts in ten companies / [ed] Marianne Döös, Lena Wilhelmson, Stockholm: Vinnova , 2009, 129-143 p.Chapter in book (Other academic)
  • 37.
    Eklund, Jörgen
    et al.
    KTH, School of Technology and Health (STH), Ergonomics.
    Svensson, Lennart
    Linköpings Universitet.
    Lean: en möjlighet till effektivitet och innovation2012In: Lean och innovationsförmåga – hinder, möjligheter och kunskapsluckor, 2012, 53-59 p.Conference paper (Other academic)
  • 38.
    Eliasson, Kristina
    et al.
    Arbets- och miljömedicin, Uppsala Universitet.
    Lind, Carl
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    Nyman, Teresia
    Arbets- och miljömedicin, Akademiska Sjukhuset; Arbets- och miljömedicin, Uppsala Universitet.
    The use of specific observation-based risk-assessment tools among professional ergonomistsManuscript (preprint) (Other academic)
    Abstract [en]

    Several observation-based risk-assessment tools have been developed in recent decades. However, studies reporting their use, the context in which they are used, and reasons for using them are scarce. The aims of the present study were to investigate the knowledge and use of observation-based risk-assessment tools and their usability and to explore the processes of assignments that include assessment of physical exposures. A web-based questionnaire (n=70) was combined with semi-structured interviews (n=12). The survey showed a limited use of several widely spread tools e.g. the NIOSH lifting equation, RULA and OWAS. The interviews revealed that the ergonomists mainly performed risk assessments based on their own expertise. Assignments were often initiated reactively, after identification of work-related musculoskeletal disorders, and seldom evaluated. The type of OHS organization and its relation to the client company seems to affect the opportunities for ergonomists to work proactively with risk assessment.

  • 39.
    Elmlund, Dominika
    KTH, School of Technology and Health (STH), Structural Biotechnology.
    Towards unbiased 3D reconstruction: in single-particle cryo-electron microscopy2010Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Cryo-electron microscopy of freestanding molecules (single-particles) plays a pivotal role in the difficult and pressing challenge of determining the structures of large macromolecular complexes. Molecular volumes are generated by aligning large sets of randomly oriented two-dimensional (2D) projection images in three dimensions (3D) before reconstruction is performed using tomographic techniques. The increasing popularity of the single-particle method is highly correlated with technical advances in instrumentation and computation. This thesis introduces new computational methods for 3D structure determination from electron microscopic projection images of single molecules. The algorithms have been developed to fill a gap in the single particle methodology – the lack of methods for ab initio 3D reconstruction of asymmetrical or low-symmetry molecules co-existing in different functional states. The proposed approach does not rely on a priori information about the structure or the character of the sample heterogeneity, which minimizes template dependence and makes the methods applicable to a wide range of single molecules. The presented algorithms constitute the basis of a new open source software package - SIMPLE (Single-particle IMage Processing Linux Engine). SIMPLE is an efficient and easy-to-use image processing system for semi-automated ab initio 3D reconstruction from challenging single-particle data sets (asymmetrical particles, significant degree of heterogeneity).

  • 40.
    Elmstedt, Nina
    KTH, School of Technology and Health (STH), Medical Engineering.
    Prenatal Tisse Velocity Imaging of the Heart: A new approach to assess fetal myocardial function2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The general aim of this thesis has been to evaluate color‐coded tissue velocity imaging (TVI) as an approach to developing a new, non‐invasive assessment method for fetal myocardial function. Such a method could hypothetically give early indications of fetal pathology, as myocardial dysfunction is often the consequence when the circulation tries to adapt to deteriorating situations. This would be beneficial in clinical decision making when evaluating fetal well‐being in a wide range of pregnancy associated conditions, to facilitate risk assessment and to monitor the benefit of therapeutic interventions.

    TVI is an ultrasound technique that enables quantification of longitudinal myocardial motion with high temporal resolution, which is essential in the identification of fetal myocardial movements of short duration. Furthermore, the longitudinal motion is mainly determined by subendocardial fibers that usually become abnormal in the very early stages of cardiac dysfunction as they are sensitive to milder degrees of hypoxia. Thus, TVI has the potential to give early indications of impaired fetal myocardial function and hypothetically facilitate the detection of intrauterine hypoxia. Hypoxia is a common phenomenon of many pathological conditions in pregnancy, from which a substantial number of children either die or acquire permanent brain injury during delivery every year.

    After having established optimal sampling requirements and ensured an acceptable reproducibility for TVI measurements of the fetal myocardium, normal reference values were determined feasible and sensitive enough to provide insight into maturational changes in myocardial function. This provided a foundation that should enable further investigations and was partly accomplished using the cardiac state diagram (CSD) to accurately time the myocardial events during a cardiac cycle according to the motion shifts of the atrioventricular plane.

    The demonstrated results are promising and the general conclusion of this thesis is that TVI contributes to increasing the knowledge and understanding of fetal myocardial function and dysfunction. Used together with CSD this technique has great potential as an assessment method. However, further testing of the clinical potential is needed in larger study populations concerning the pathological or physiological questions at issue, and additional development of the method is required to render the method simple enough to be of potential aid in clinical practice.

  • 41.
    Engkvist, Inga-Lill
    KTH, School of Technology and Health (STH), Ergonomics.
    Inventering av förfarande vid nyanställning och arbetsskador samt hälsofrämjande personalåtgärder för styckare: Intervjuer utförda vid 10 av de största företagen i Sverige2012Report (Other academic)
  • 42.
    Eriksson, Magnus G.
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Haptic Milling Simulation in Six Degrees-of-Freedom: With Application to Surgery in Stiff Tissue2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The research presented in this thesis describes a substantial part of the design of a prototypical surgical training simulator. The results are intended to be applied in future simulators used to educate and train surgeons for bone milling operations. In earlier work we have developed a haptic bone milling surgery simulator prototype based on three degrees-of-freedom force feedback. The contributions presented here constitute an extension to that work by further developing the haptic algorithms to enable six degrees-of-freedom (6-DOF) haptic feedback. Such feedback is crucial for a realistic haptic experience when interacting in a more complex virtual environment, particularly in milling applications.The main contributions of this thesis are:The developed 6-DOF haptic algorithm is based on the work done by Barbic and James, but differs in that the algorithm is modified and optimized for milling applications. The new algorithm handles the challenging problem of real-time rendering of volume data changes due to material removal, while fulfilling the requirements on stability and smoothness of the kind of haptic applications that we approach. The material removal algorithm and the graphic rendering presented here are based on the earlier research. The new 6-DOF haptic milling algorithm is characterized by voxel-based collision detection, penalty-based and constraint-based haptic feedback, and by using a virtual coupling for stable interaction.Milling a hole in an object in the virtual environment or dragging the virtual tool along the surface of a virtual object shall generate realistic contact force and torque in the correct directions. These are important requirements for a bone milling simulator to be used as a future training tool in the curriculum of surgeons. The goal of this thesis is to present and state the quality of a newly developed 6-DOF haptic milling algorithm. The quality of the algorithm is confirmed through a verification test and a face validity study performed in collaboration with the Division of Orthopedics at the Karolinska University Hospital. In a simulator prototype, the haptic algorithm is implemented together with a new 6-DOF haptic device based on parallel kinematics. This device is developed with workspace, transparency and stiffness characteristics specifically adapted to the particular procedure. This thesis is focuses on the 6-DOF haptic algorithm.

  • 43.
    Ferreira Gonzalez, Javier
    KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS).
    Textile-enabled Bioimpedance Instrumentation for Personalised Health Monitoring Applications2013Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    A growing number of factors, including the costs, technological advancements, an ageing population, and medical errors are leading industrialised countries to invest in research on alternative solutions to improving their health care systems and increasing patients’ life quality. Personal Health System (PHS) solutions envision the use of information and communication technologies that enable a paradigm shift from the traditional hospital-centred healthcare delivery model toward a preventive and person-centred approach. PHS offers the means to follow patient health using wearable, portable or implantable systems that offer ubiquitous, unobtrusive bio-data acquisition, allowing remote access to patient status and treatment monitoring.

    Electrical Bioimpedance (EBI) technology is a non-invasive, quick and relatively affordable technique that can be used for assessing and monitoring different health conditions, e.g., body composition assessments for nutrition. EBI technology combined with state-of-the-art advances in sensor and textile technology are fostering the implementation of wearable bioimpedance monitors that use functional garments for the implementation of personalised healthcare applications.

    This research studies the development of a portable EBI spectrometer that can use dry textile electrodes for the assessment of body composition for the purposes of clinical uses. The portable bioimpedance monitor has been developed using the latest advances in system-on-chip technology for bioimpedance spectroscopy instrumentation. The obtained portable spectrometer has been validated against commercial spectrometer that performs total body composition assessment using functional textrode garments.

    The development of a portable Bioimpedance spectrometer using functional garments and dry textile electrodes for body composition assessment has been shown to be a feasible option. The availability of such measurement systems bring closer the real implementation of personalised healthcare systems.

  • 44.
    Ferreira, Javier
    KTH, School of Technology and Health (STH), Medical Engineering. Högskolan i Borås.
    Modular textile-enabled bioimpedance system for personalized health monitoring applications2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    A growing number of factors, including costs, technological advancements, ageing populations, and medical errors, are leading industrialized countries to invest in research on alternative solutions to improve their health-care systems and increase patients’ quality of life. Personal health systems (PHS) examplify the use of information and communication technologies that enable a paradigm shift from the traditional hospital-centered healthcare delivery model toward a preventive and person-centered approach. PHS offer the means to monitor a patient’s health using wearable, portable or implantable systems that offer ubiquitous, unobtrusive biodata

    acquisition, allowing remote monitoring of treatment and access to the patient’s status. Electrical bioimpedance (EBI) technology is non-invasive, quick and relatively affordable technique that can be used for assessing and monitoring different health conditions, e.g., body composition assessments for nutrition. When combined with state-of-the-art advances in sensors and textiles, EBI technologies are fostering the implementation of wearable bioimpedance monitors that use functional garments for personalized healthcare applications. This research work is

    focused on the development of wearable EBI-based monitoring systems for ubiquitous health monitoring applications. The monitoring systems are built upon portable monitoring instrumentation and custom-made textile electrode garments.

    Portable EBI-based monitors have been developed using the latest material technology and advances in system-on-chip technology. For instance, a portable EBI spectrometer has been validated against a commercial spectrometer for total body composition assessment using functional textile electrode garments. The development of wearable EBI-based monitoring units using functional garments and dry textile electrodes for body composition assessment and respiratory monitoring has been shown to be a feasible approach. The availability of these measurement systems indicates progress toward the real implementation of personalized healthcare systems.

  • 45.
    Frånberg, Oskar
    KTH, School of Technology and Health (STH), Basic Science and Biomedicine, Environmental Physiology.
    Oxygen content in semi-closed rebreathing apparatuses for underwater use: Measurements and modeling2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The present series of unmanned hyperbaric tests were conducted in order to investigate the oxygen fraction variability in semi-closed underwater rebreathing apparatuses. The tested rebreathers were RB80 (Halcyon dive systems, High springs, FL, USA), IS-Mix (Interspiro AB, Stockholm, Sweden), CRABE (Aqua Lung, Carros Cedex, France), and Viper+ (Cobham plc, Davenport, IA, USA). The tests were conducted using a catalytically based propene combusting metabolic simulator. The metabolic simulator connected to a breathing simulator, both placed inside a hyperbaric pressure chamber, was first tested to demonstrate its usefulness to simulate human respiration in a hyperbaric situation. Following this the metabolic simulator was shown to be a useful tool in accident investigations as well as to assess the impact of different engineering designs and physiological variables on the oxygen content in the gas delivered to the diver by the rebreathing apparatuses. A multi-compartment model of the oxygen fractions was developed and compared to the previously published single-compartment models. The root mean squared error (RMSE) of the multi-compartment model was smaller than the RMSE for the single-compartment model, showing its usefulness to estimate the impact of different designs and physiological variables on the inspired oxygen fraction.

  • 46.
    Frånberg, Oskar
    et al.
    KTH, School of Technology and Health (STH), Basic Science and Biomedicine, Environmental Physiology.
    Gennser, Mikael
    KTH, School of Technology and Health (STH), Basic Science and Biomedicine, Environmental Physiology.
    Modeling a demand constant volume ratio exhaust and a self-mixing constant oxygen injection semi-closed rebreatherManuscript (preprint) (Other academic)
    Abstract [en]

    Unmanned tests of two types of gas dosage techniques for semi-closed underwater rebreathing apparatuses were carried out with a metabolic simulator in a water filled pressure chamber. Tests were conducted over a wide range of tidal volumes (0.5-3 L), respiratory frequencies (5-25 min-1), and oxygen consumptions (0.5-4 L/min), as well as with changing chamber pressures from 100 kPa to 920 kPa. Two models were set up, one single compartment model and one model assuming multiple serial compartments. Both models seem to have about the same level of accuracy at predicting the inspired oxygen levels at pressure, but the surface tests seem to favor the serial compartments model.

  • 47.
    Giordano, Chiara
    KTH, School of Technology and Health (STH), Medical Engineering, Neuronic Engineering.
    Development of an Anisotropic Finite Element Head Model for Traumatic Brain Injury Prediction2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Traumatic brain injury (TBI) is a worldwide health care problem with very high associatedmorbidity and mortality rates. In particular, the diagnosis of TBI is challenging: symptomsoverlap with other pathologies and the injury is typically not visible with conventionalneuroimaging techniques.Finite element (FE) head models can provide valuable insight into uncovering themechanism underlying brain damage. These models enable the calculation of tissue loadsand deformation patterns, which are thought to be associated with the injury. Measuresbased on tissue strain or invariants of the strain tensor are used as injury predictors and riskinjury curves can be inferred to establish the tolerance of the human head to external loads.However, while in-vitro research shows that the vulnerability to injury is due to highlyorganized structure in white matter tracts, the majority of the current FE models model thebrain as isotropic and homogenous. The deformation of white matter tracts is not calculated.The aim of this doctoral thesis was to incorporate the effects of inhomogeneity andanisotropy of brain tissue into injury analysis. Based on in-vitro experimental evidence, thestrain in the direction of the axons (axonal strain) was proposed as a new, more anatomicallyrelevant, injury predictor. The initial hypothesis to investigate was that an FE anisotropichead model is a better tool to represent TBI because it is more biofidelic in describing thelocal mechanism of axonal impairment.The studies reported in this thesis describe a method for implementing the orientation of thewhite matter tracts in an anisotropic constitutive law for FE modeling. Results from thestudies suggested that the anisotropy of the brain significantly affected the injury predictionsof an FE head model. For an injury dataset from the American National Football League, thepeak of axonal strain - MAS - was found to be a better predictor of injury than isotropic localor global predictors. Finally, based on 27 cases of intracranial pressure, relative skull-brainmotion and brain deformation, the introduction of the brain anisotropy in the FE modelpartially enhanced the biofidelity of the simulations. However, given that the enhancementin biofidelity was not major, it was concluded that further research is necessary forunderstanding the relationship between tissue-level loading and axonal injury.

  • 48.
    Glimskär, Bo
    KTH, School of Technology and Health (STH), Centres, Centre for Health and Building, CHB.
    Developments for a future health care at home step by step2010In: Safety Science Monitor, ISSN 1443-8844, Vol. 14, no 1Article in journal (Other academic)
  • 49.
    Glimskär, Bo
    KTH, School of Technology and Health (STH), Centres, Centre for Health and Building, CHB.
    The Adoption of Ergonomic Innovations for Injury Prevention: Examples from the building construction and health care industries2014Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    A good work environment is important for the individual, for industry and for society. The work environment research has, predominantly, targeted identification of problems and the measurement of the size of these problems.

    Innovations to reduce the incidence of musculoskeletal disorder, MSD, have been introduced in different branches of industry, but with limited success.

    Few of the ergonomic innovations developed for the building and construction industry have reached a sufficient level of adoption. Ergonomic innovations in the health care sector are of an incremental character and seem to have similar problems of adoption as the ones in the building and construction industry.

    Three examples of ergonomic innovation are examined in the thesis:

    • a glue spreader for floor layers

    • a four-wheel walker with a lifting device

    • a sonographer’s scanning support device

    The studies show that an ergonomic innovation is not adopted for prevention of occupational injury unless the innovation also has other relative advantages apart from the ergonomic ones. For the group who already has sustained an injury, it is enough that the ergonomic problems are solved, while the other, symptom-free group, requires other advantages in order to adopt the innovation; increased production economy seems to be the most prominent potential advantage.

  • 50.
    Glimskär, Bo
    KTH, School of Technology and Health (STH), Centres, Centre for Health and Building, CHB.
    The Adoption of Ergonomic Innovations for Injury Prevention: Sonographer's scanning support deviceManuscript (preprint) (Other academic)
    Abstract [en]

    Studies of how people relate to the risk of occupational injury indicate that there is a tendency to underestimate the risk at work compared to other risks in society. Ultrasound examinations of the heart involve a static and very uncomfortable working posture for the sonographer. As a result many sonographers experience shoulder and neck pains which can result in long term sickness leaves.

    The purpose of the study was to evaluate how a more radical ergonomic innovation, a remote controlled ultrasound robot for cardiac examinations, Medirob, has been adopted. The study was conducted by interviews with department heads and heads of clinics, responsible for the procurement of the equipment.

    The results of this study have shown that it is not maybe enough to solve an ergonomic problem with an innovation to get it accepted and used. To prevent injuries the intervention must also have other qualities, for example improved productivity.

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