| 1. |
- Bengtsson, Lars, et al.
(author)
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Open to a Select Few? Matching Partners and Knowledge Content for Open Innovation Performance
- 2015
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In: Creativity and Innovation Management. - : John Wiley & Sons. - 0963-1690 .- 1467-8691. ; 24:1, s. 72-86
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Journal article (peer-reviewed)abstract
- The purpose of the paper is to illuminate the costs and benefits of crossing firm boundaries in inbound open innovation (OI) by determining the relationships among partner types, knowledge content and performance. The empirical part of the study is based on a survey of OI collaborations answered by R&D managers in 415 Italian, Finnish and Swedish firms. The results show that the depth of collaboration with different partners (academic/consultants, value chain partners, competitors and firms in other industries) is positively related to innovation performance, whereas the number of different partners and size have negative effects. The main result is that the knowledge content of the collaboration moderates the performance outcomes and the negative impact of having too many different kinds of partners. This illustrates how successful firms use selective collaboration strategies characterized by linking explorative and exploitative knowledge content to specific partners, to leverage the benefits and limit the costs of knowledge boundary crossing processes.
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| 2. |
- Bengtsson, Olof, et al.
(author)
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A Computational Load-Pull Method for TCAD Optimization of RF-Power Transistors in Bias-Modulation Applications
- 2008
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In: Proceedings of the 3rd European Microwave Integrated Circuits Conference. - 9782874870071
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Conference paper (peer-reviewed)abstract
- In this paper a method for TCAD evaluation of RF-Power transistors for high-efficiency operation using drain bias-modulation is presented. The method is based on large signal time-domain transient computational load-pull. With the method, intrinsic device parasitics and mechanisms affecting device efficiency under drain bias modulation can be investigated and optimized for the application making it very useful for RFIC design. A case study has been done on a CMOS compatible LDMOS. For verification under dynamic operation two-tone signals with varying envelope has been simulated. The results show a possible 15% increase in the efficiency of a modulated signal for the studied device at the expense of increased phase distortion observable also in the time-domain waveforms generated. Since the method is based on TCAD it is also useful in the investigation of e.g. dynamic breakdown during high envelope under bias-modulation operation.
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| 3. |
- Bengtsson, Olof, et al.
(author)
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A Computational Load-Pull Method with Harmonic Loading for High-Efficiency Investigations
- 2009
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In: Solid-State Electronics. - : Elsevier BV. - 0038-1101 .- 1879-2405. ; 53:1, s. 86-94
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Journal article (peer-reviewed)abstract
- In this paper a method for TCAD evaluation of RF-power transistors in high-efficiency operation using harmonic loading is presented. The method is based on large signal time-domain computational load-pull. Active loads are used in the harmonic load-pull for simulation time reduction. With the method device performance under different harmonic load impedance can be investigated at an early stage in the design process. Alternative designs can be compared and the mechanisms affecting device efficiency in class-F can be studied at chip-level. For method validation, a case study is made on an LDMOS transistor. The transistor is load-pulled in class-AB and then optimized for efficiency at 2f0 and 3f0 using a novel approach with passive fundamental load and active harmonic loads. A swept simulation is conducted using passive fundamental and harmonic loads. Waveforms in compression are analyzed and the mechanisms creating the increased efficiency in class-F are identified by a comparative study to class-AB. Class-F harmonic termination is shown to give a 17% overall reduction of dissipated power and a 9% increase in output power. The expected efficiency increase is about 3–10% in the compression region depending on level of compression.
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| 4. |
- Bengtsson, Olof, et al.
(author)
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A Method for Device Intermodulation Analysis from 2D, TCAD Simulations using a Time-domain Waveform Approach
- 2006
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In: Proceedings of the 36th European Microwave Conference. ; , s. 169-171
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Conference paper (peer-reviewed)abstract
- This paper describes a fast method useful for IMD analysis at TCAD design level. The method is based on the static load-line transfer function extracted from 2D device simulations. The transfer function is exposed to a time domain signal through a look-up table and the output response is analyzed using the Fast Fourier Transform. The response is compared to measurements of a fabricated device. The method is shown to accurately predict the IMD behavior of a two-tone signal for the 3’rd, 5’th and 7’th order IMD products with regards to sweet spot tracking and relative IMD magnitude. We present a fast and simple way to predict IMD performance from TCAD simulations at an early stage in the design process. The method enables prediction of output response from any signal due to the time domain approach.
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| 5. |
- Bengtsson, Olof, 1969-
(author)
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Design and Characterization of RF-Power LDMOS Transistors
- 2008
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Doctoral thesis (other academic/artistic)abstract
- In mobile communication new applications like wireless internet and mobile video have increased the demand of data-rates. Therefore, new more wideband systems are being implemented. Power amplifiers in the base-stations that simultaneously handle these wideband signals for many terminals (handhelds) need to be highly linear with a considerable band-width. In the past decade LDMOS has been the dominating technology for use in these RF-power amplifiers. In this work LDMOS transistors possible to fabricate in a normal CMOS process have been optimized and analyzed for RF-power applications. Their non-linear behavior has been explored using load-pull measurements. The mechanisms of the non-linear input capacitance have been analyzed using 2D TCAD simulations. The investigation shows that the input capacitance is a large contributor to phase distortion in the transistor. Computational load-pull TCAD methods have been developed for analysis of RF-power devices in high-efficiency operation. Methods have been developed for class-F with harmonic loading and for bias-modulation. Load-pull measurements with drain-bias modulation in a novel measurement setup have also been conducted. The investigation shows that the combination of computational load-pull of physical transistor structures and direct measurement evaluation with modified load-pull is a viable alternative for future design of RF-power devices. Simulations and measurements on the designed LDMOS shows a 10 to 15 % increase in drain efficiency in mid-power range both in simulations and measurements. The computational load-pull method has also been used to investigate the power capability of LDMOS transistors on SOI. This study indicates that either a low-resistivity or high-resistivity substrate should be used in manufacturing of RF-power LDMOS transistors on SOI to achieve optimum efficiency. Based on a proper substrate selection these devices exhibit a 10 % higher drain-efficiency mainly due to lower dissipated power in the devices.
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| 6. |
- Bengtsson, Olof, et al.
(author)
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Investigation of SOI-LDMOS for RF-power applications using Computational Load-Pull
- 2009
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In: IEEE Transactions on Electron Devices. - : IEEE. - 0018-9383 .- 1557-9646. ; 56:3, s. 505-511
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Journal article (peer-reviewed)abstract
- Small-signal and computational load-pull simulations are used to investigate the effect of substrate resistivity on efficiency in high-power operation of high-frequency silicon-on-insulator-LDMOS transistors. Identical transistors are studied on substrates with different resistivities. Using computational load pull, their high-power performance is evaluated. The results are compared to previous investigations, relating the OFF-state output resistance to high-efficiency operation. From the large-signal simulation, an output circuit model based on a load-line match is extracted with parameters traceable from small-signal simulations. It is shown that, albeit high OFF-state output resistance is a good indication, it is not sufficient for high efficiency in a high-power operation. The bias and frequency dependence of the coupling through the substrate makes a more detailed ON-state analysis necessary. It is shown that very low resistivity and high-resistivity SOI substrates both result in a high efficiency at the studied frequency and bias point. It is also shown that a normally doped medium-resistivity substrate results in a significantly lower efficiency.
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| 7. |
- Bengtsson, Olof, et al.
(author)
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Investigation of the non-linear input capacitance in LDMOS transistors and its contribution to IMD and phase distortion
- 2008
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In: Solid-State Electronics. - : Elsevier BV. - 0038-1101 .- 1879-2405. ; 52:7, s. 1024-1031
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Journal article (peer-reviewed)abstract
- In this paper the mechanisms causing the capacitive, reactive non-linearities in a lateral double diffused MOS, LDMOS, transistor are investigated. The non-linear input capacitance under load-line power match is extracted and analyzed. Computational TCAD load-pull is used to analyze the effect of non-linear capacitance on two-tone intermodulation distortion and AM–PM conversion in class-A operation. High-frequency measurements have been made to verify the use of 2D numerical device simulations for the analysis. It is found that the input capacitance, Cgg, of the LDMOS transistor working under power match conditions is a strongly non-linear function of gate voltage Vg but with an almost linear initial increase in Cgg. The voltage dependence of Cgg is found to mainly affect higher order IMD products in class-A operation. Transient simulations however show that Cgg seriously contributes to the onset of AM–PM conversion well below the 1 dB compression point.
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| 8. |
- Kaltenbrunner, Monica, 1975-, et al.
(author)
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A questionnaire measuring staff perceptions of Lean adoption in healthcare : development and psychometric testing
- 2017
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In: BMC Health Services Research. - : Springer Science and Business Media LLC. - 1472-6963. ; 17:1
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Journal article (peer-reviewed)abstract
- BACKGROUND: During the past decade, the concept of Lean has spread rapidly within the healthcare sector, but there is a lack of instruments that can measure staff's perceptions of Lean adoption. Thus, the aim of the present study was to develop a questionnaire measuring Lean in healthcare, based on Liker's description of Lean, by adapting an existing instrument developed for the service sector.METHODS: A mixed-method design was used. Initially, items from the service sector instrument were categorized according to Liker's 14 principles describing Lean within four domains: philosophy, processes, people and partners and problem-solving. Items were lacking for three of Liker's principles and were therefore developed de novo. Think-aloud interviews were conducted with 12 healthcare staff from different professions to contextualize and examine the face validity of the questionnaire prototype. Thereafter, the adjusted questionnaire's psychometric properties were assessed on the basis of a cross-sectional survey among 386 staff working in primary care.RESULTS: The think-aloud interviews led to adjustments in the questionnaire to better suit a healthcare context, and the number of items was reduced. Confirmatory factor analysis of the adjusted questionnaire showed a generally acceptable correspondence with Liker's description of Lean. Internal consistency, measured using Cronbach's alpha, for the factors in Liker's description of Lean was 0.60 for the factor people and partners, and over 0.70 for the three other factors. Test-retest reliability measured by the intra-class correlation coefficient ranged from 0.77 to 0.88 for the four factors.CONCLUSIONS: We designed a questionnaire capturing staff's perceptions of Lean adoption in healthcare on the basis of Liker's description. This Lean in Healthcare Questionnaire (LiHcQ) showed generally acceptable psychometric properties, which supports its usability for measuring Lean adoption in healthcare. We suggest that further research focus on verifying the usability of LiHcQ in other healthcare settings, and on adjusting the instrument if needed.
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| 9. |
- Kaltenbrunner, Monica, 1975-, et al.
(author)
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Associations between lean maturity in primary care and musculoskeletal complaints among staff : a longitudinal study
- 2023
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In: BMJ Open. - : BMJ Publishing Group Ltd. - 2044-6055. ; 13:2
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Journal article (peer-reviewed)abstract
- ObjectiveThis study had two aims: (1) to determine the prevalence of musculoskeletal complaints among staff in primary care and (2) to determine to what extent lean maturity of the primary care unit can predict musculoskeletal complaints 1 year later.DesignDescriptive, correlational and longitudinal design.SettingPrimary care units in mid-Sweden.ParticipantsIn 2015, staff members responded to a web survey addressing lean maturity and musculoskeletal complaints. The survey was completed by 481 staff members (response rate 46%) at 48 units; 260 staff members at 46 units also completed the survey in 2016.Outcome measuresAssociations with musculoskeletal complaints were determined both for lean maturity in total and for four Lean domains entered separately in a multivariate model, that is, philosophy, processes, people and partners, and problem solving.ResultsThe shoulders (12-month prevalence: 58%), neck (54%) and low back (50%) were the most common sites of 12-month retrospective musculoskeletal complaints at baseline. Shoulders, neck and low back also showed the most complaints for the preceding 7 days (37%, 33% and 25%, respectively). The prevalence of complaints was similar at the 1-year follow-up. Total lean maturity in 2015 was not associated with musculoskeletal complaints, neither cross-sectionally nor 1 year later, for shoulders (1 year beta: -0.002, 95% CI -0.03 to 0.02), neck (beta: 0.006, 95% CI -0.01 to 0.03), low back (beta: 0.004, 95% CI -0.02 to 0.03) and upper back (beta: 0.002, 95% CI -0.02 to 0.02).ConclusionThe prevalence of musculoskeletal complaints among primary care staff was high and did not change within a year. The extent of lean maturity at the care unit was not associated with complaints among staff, neither in cross-sectional analyses nor in a 1-year predictive analysis.
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| 10. |
- Kaltenbrunner, Monica, 1975-, et al.
(author)
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Lean maturity and quality in primary care
- 2019
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In: Journal of Health Organization & Management. - : Emerald Group Publishing Limited. - 1477-7266 .- 1758-7247. ; 32:2, s. 141-154
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Journal article (peer-reviewed)abstract
- Purpose - The purpose of this paper is to 1) describe Lean maturity in primary care using a questionnaire based on Liker’s description of Lean, complemented with observations, and 2) determine the extent to which Lean maturity is associated with quality of care measured as staff-rated satisfaction with care and adherence to national guidelines. High Lean maturity indicates adoption of all Lean principles throughout the organization and by all staff.Design/methodology/approach - Data were collected using a survey based on Liker’s four principles, divided into 16 items (n = 298 staff in 45 units). Complementary observations (n = 28 staff) were carried out at four units.Findings - Lean maturity varied both between and within units. The highest Lean maturity was found for ‘adhering to routines’ and the lowest for ‘having a change agent at the unit’. Lean maturity was positively associated with satisfaction with care and with adherence to national guidelines to improve healthcare quality. Practical implications - Quality of primary care may benefit from increasing Lean maturity. When implementing Lean, managers could benefit from measuring and adopting Lean maturity repeatedly, addressing all Liker’s principles and using the results as guidance for further development.Originality/value - This is one of the first studies to evaluate Lean maturity in primary care, addressing all Liker’s principles from the perspective of quality of care. The results suggest that repeated actions based on evaluations of Lean maturity may help to improve quality of care.
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