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Sökning: WFRF:(Öwall B.)

  • Resultat 1-33 av 33
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1.
  • Hermerén, Göran, et al. (författare)
  • Etik och estetisk tandvård.
  • 2006
  • Ingår i: Tandläkartidningen. ; 15, s. 62-66
  • Tidskriftsartikel (refereegranskat)
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2.
  • Öwall, B., et al. (författare)
  • Estetisk och kosmetisk tandvård. Nytt och unikt eller gamla metoder som vidareutvecklats?
  • 2005
  • Ingår i: Tandläkartidningen. - 0039-6982. ; 97:5
  • Tidskriftsartikel (refereegranskat)abstract
    • Intresset för estetisk/kosmetisk tandvård är stort och ökar snabbt. Det stora intresset skulle kunna vara positivt för tandvården men har i stället resulterat i olika reaktioner bland tandläkare. Den snabba utvecklingen inom området har ökat den kunnige tandläkarens möjligheter att förbättra patienternas dentala estetik. Men det har även visat sig att tandläkares och patienters uppfattningar om vad som är vackert, estetiskt acceptabelt och fult skiljer sig åt. Detta behöver studeras ytterligare. Den odontologiska litteraturen innehåller en mängd artiklar och böcker i ämnet men det finns förhållandevis få vetenskapliga studier. Det är också svårt att hitta artiklar som ifrågasätter området. Grundinställningen är att det är positivt att försöka förbättra tändernas utseende. De flesta material och metoder inom estetisk tandvård tycks vara relativt ofarliga att använda, åtminstone på kort sikt. Kunskaperna om resultat och risker på längre sikt är dock begränsade. Det är även brist på långtidsstudier som jämför kostnader för olika material och metoder. Tandläkare bör därför vara försiktiga med att använda nyheter som marknadsförs okritiskt, utan relevanta kliniska studier.
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3.
  • Anderson, John B, et al. (författare)
  • Faster-Than-Nyquist Signaling
  • 2013
  • Ingår i: Proceedings of the IEEE. - 0018-9219. ; 101:8, s. 1817-1830
  • Tidskriftsartikel (refereegranskat)abstract
    • In this paper, we survey Faster-than-Nyquist (FTN) signaling, an extension of ordinary linear modulation in which the usual data bearing pulses are simply sent faster, and consequently are no longer orthogonal. Far from a disadvantage, this innovation can transmit up to twice the bits as ordinary modulation at the same bit energy, spectrum, and error rate. The method is directly applicable to orthogonal frequency division multiplex (OFDM) and quadrature amplitude modulation (QAM) signaling. Performance results for a number of practical systems are presented. FTN signaling raises a number of basic issues in communication theory and practice. The Shannon capacity of the signals is considerably higher.
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4.
  • Dasalukunte, Deepak, et al. (författare)
  • A Transmitter Architecture for Faster-than-Nyquist Signaling Systems
  • 2009
  • Ingår i: Proceedings, IEEE International Symposium on Circuits and Systems, 2009. - 9781424438273 ; , s. 1028-1031
  • Konferensbidrag (refereegranskat)abstract
    • This paper presents the complexity analysis of a transmitter architecture for a faster-than-Nyquist (FTN) system. Complexity issues in terms of computations and memory requirements to achieve an FTN system are dealt with. An OFDM based multi-carrier system is considered as it is one of the most widely used in upcoming wireless standards. Retaining the modules within the OFDM transmitter helps in exploiting the already optimized and hardware efficient structures, the IFFT being one. From an implementation perspective the introduction of FTN introduces negligible overhead for the transmitter.
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5.
  • Dasalukunte, Deepak, et al. (författare)
  • Design and Implementation of Iterative Decoder for Faster-than-Nyquist Signaling Multicarrier systems
  • 2011
  • Ingår i: [Host publication title missing]. - 2159-3477. ; , s. 359-360
  • Konferensbidrag (refereegranskat)abstract
    • Abstract in UndeterminedFaster-than-Nyquist (FTN) signaling is a method of improving bandwidth efficiency by transmitting information beyond Nyquist's orthogonality limit for interference free transmission. Previously have theoretically established that FTN can provide improved bandwidth efficiency. However, this comes at the cost of higher decoding complexity at the receiver. Our work has evaluated multicarrier FTN signaling for its implementation feasibility and complexity overhead compared to the gains in bandwidth efficiency. The work carried out in this research project includes a systems perspective evaluating performance, algorithm hardware tradeoffs and a hardware architecture leading to a silicon implementation of the decoder for FTN signaling. From the systems perspective, co-existence of FTN and OFDM based multicarrier system has been evaluated. OFDM being a part of many existing and upcoming broadband access technologies such as WLAN, LTE, DVB, this analogy is motivated. On the hardware aspect, the proposed architecture can accommodate both OFDM and FTN systems. The processing blocks in transmitter and receiver were designed for reuse and carry out different functions in the transceiver. Furthemore, the hardware could be configured to operate at varying bandwidth efficiencies (by FTN signaling) to exploit the channel conditions. The decoder implementation also considered block sizes and data rates to comply with the 3GPP standard. The decoding is carried out in as few as 8 iterations making it more practical for implementation in power constrained mobile devices. The decoder is implemented in 65nm CMOS process and occupies a total chip area of 0.8mm2.
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7.
  • Hermeren, Göran, et al. (författare)
  • Etik och estetisk tandvård
  • 2006
  • Ingår i: Tandläkartidningen. - 0039-6982. ; 98:15, s. 62-66
  • Forskningsöversikt (refereegranskat)abstract
    • The objective of the article was to present the background and the rules of regulations for the ethic considerations that are mandatory in aesthetic dentistry. It also presents a systematic approach in the handling of the ethic analysis.
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8.
  • Kamuf, Matthias, et al. (författare)
  • A hardware efficiency analysis for simplified trellis decoding blocks
  • 2005
  • Ingår i: [Host publication title missing]. - 1520-6130. - 0780393333 ; 2005, s. 128-132
  • Konferensbidrag (refereegranskat)abstract
    • Two simplifications for trellis decoding blocks are analyzed in terms of hardware efficiency. Both architectures use a complementary property of the best rate 1/n convolutional codes to reduce arithmetic complexity. While the reduction can be calculated straightforward in the first approach (17%), the other approach relies on modified computational operations and hence this reduction is not as evident. It is shown that for rate 1/2 codes the first approach is preferable for hardware implementation in terms of area and speed.
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9.
  • Kamuf, Matthias, et al. (författare)
  • A simplified computational kernel for trellis-based decoding
  • 2004
  • Ingår i: IEEE Communications Letters. - 1089-7798. ; 8:3, s. 156-158
  • Tidskriftsartikel (refereegranskat)abstract
    • A simplified branch metric and add-compare-select (ACS) unit is presented for use in trellis-based decoding architectures. The simplification is based on a complementary property of best feedforward and some systematic feedback encoders. As a result, one adder is saved in every other ACS unit. Furthermore, only half the branch metrics have to be calculated. It is shown that this simplification becomes especially beneficial for rate 1/2 convolutional codes. Consequently, area and power consumption will be reduced in a hardware implementation.
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10.
  • Kamuf, Matthias, et al. (författare)
  • A variable-rate Viterbi decoder in 130-nm CMOS: design, measurements, and cost of flexibility
  • 2008
  • Ingår i: Proceedings, Norchip Conference. ; , s. 137-141
  • Konferensbidrag (refereegranskat)abstract
    • This paper discusses design and measurements of a flexible Viterbi decoder fabricated in 130-nm digital CMOS. Flexibility was incorporated by providing various code rates and modulation schemes to adjust to varying channel conditions. Based on previous trade-off studies, flexible building blocks were carefully designed to cause as little area penalty as possible. The chip runs down to a minimal core supply of 0.8V. It turns out that striving for more modulation schemes is beneficial in terms of power consumption once the price is paid for accepting different code rates viz. radices in the trellis and survivor path units.
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11.
  • Kamuf, Matthias, et al. (författare)
  • Architectural considerations for rate-flexible trellis processing blocks
  • 2005
  • Ingår i: 2005 IEEE 16th International Symposium on Personal, Indoor and Mobile Radio Communications. - 9783800729098 ; , s. 1076-1080
  • Konferensbidrag (refereegranskat)abstract
    • A flexible channel decoding platform should be able to operate in varying communication scenarios, and different code rates have to be supported. Therefore, we present a framework that allows efficient processing of rate-flexible trellises. Using a fundamental computational unit for trellis-based decoding, formal principles are obtained to emulate more complex trellises. In a design example, such a computational block supports both rate 1/c convolutional codes and set partition codes with subset selectors of rate 2/3. Synthesis results show the hardware requirements for two different architectural approaches
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12.
  • Kamuf, Matthias, et al. (författare)
  • Area and power efficient trellis computational blocks in 0.13μm CMOS
  • 2005
  • Ingår i: IEEE International Symposium on Circuits and Systems (ISCAS). - 0780388348 ; , s. 344-347
  • Konferensbidrag (refereegranskat)abstract
    • Improved add-compare-select and branch metric units are presented to reduce the complexity in the implementation of trellis-based decoding architectures. These units use a complementary property of the best rate 1/2 convolutional codes to reduce both area requirements and power consumption in a silicon implementation with no loss in decoding performance. For a 0.13μm CMOS process, synthesized computational blocks for decoders that can process codes from memory 2 up to 7 show up to 17% savings in both cell area and power consumption
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14.
  • Kamuf, Matthias, et al. (författare)
  • Design and Measurement of a Variable-Rate Viterbi Decoder in 130-nm Digital CMOS
  • 2010
  • Ingår i: Microprocessors and Microsystems. - : Elsevier BV. - 0141-9331. ; 34:2010, s. 129-137
  • Tidskriftsartikel (refereegranskat)abstract
    • This paper discusses design and measurements of a flexible Viterbi decoder fabricated in 130-nm digital CMOS. Flexibility was incorporated by providing various code rates and modulation schemes to adjust to varying channel conditions. Based on previous trade-off studies, flexible building blocks were carefully designed to cause as little area penalty as possible. The chip runs down to a minimal core supply of 0.8V. It turns out that striving for more modulation schemes is beneficial in terms of power consumption once the price is paid for accepting different code rates viz. radices in the trellis and survivor path units.
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16.
  • Kamuf, Matthias, et al. (författare)
  • Optimization and implementation of a Viterbi decoder under flexibility constraints
  • 2008
  • Ingår i: IEEE Transactions on Circuits and Systems Part 1: Regular Papers. - 1549-8328. ; 55:8, s. 2411-2422
  • Tidskriftsartikel (refereegranskat)abstract
    • This paper discusses the impact of flexibility when designing a Viterbi decoder for both convolutional and TCM codes. Different trade-offs have to be considered in choosing the right architecture for the processing blocks and the resulting hardware penalty is evaluated. We study the impact of symbol quantization that degrades performance and affects the wordlength of the rate-flexible trellis datapath. A radix-2-based architecture for this datapath relaxes the hardware requirements on the branch metric and survivor path blocks substantially. The cost of flexibility in terms of cell area and power consumption is explored by an investigation of synthesized designs that provide different transmission rates. Two designs are fabricated in a digital 0.13- $mu{hbox {m}}$ CMOS process. Based on post-layout simulations, a symbol baud rate of 168 Mbaud/s is achieved in TCM mode, equivalent to a maximum throughput of 840 Mbit/s using a 64-QAM constellation.
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17.
  • Kamuf, Matthias, et al. (författare)
  • Providing flexibility in a convolutional encoder
  • 2003
  • Ingår i: Proceedings of the 2003 IEEE International Symposium on Circuits and Systems (Cat. No.03CH37430). - 0780377613 ; , s. 272-275
  • Konferensbidrag (refereegranskat)abstract
    • In future radio systems, flexible coding and decoding architectures will be required. In case of the latter, implementing architectural flexibility with regard to low power issues is a challenging task. The flexible encoding platform in this paper is a first step toward this envisioned decoder. It generates a wide class of codes, starting with convolutional codes. As an extension to this, turbo codes will be included by adding an interleaver. At this prototyping stage, the system is implemented on an FPGA. The decision to choose the observer canonical form is defended by a thorough investigation of its critical path properties. Proper configuration allows code rates of b/c, b=1 ... 15, c=2 ... 16, b
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18.
  • Kamuf, Matthias, et al. (författare)
  • Survivor path processing in Viterbi decoders using register exchange and traceforward
  • 2007
  • Ingår i: IEEE Transactions on Circuits and Systems II: Express Briefs. - 1549-7747. ; 54:6, s. 537-541
  • Tidskriftsartikel (refereegranskat)abstract
    • This paper proposes a new class of hybrid VLSI architectures for survivor path processing to be used in Viterbi decoders. The architecture combines the benefits of register exchange and trace-forward algorithms, that is, low memory requirement and latency versus implementation efficiency. Based on a structural comparison, it becomes evident that the architecture can be efficiently applied to codes with a larger number of states where usually trace-back-based architectures, which increase latency, are dominant.
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19.
  • Larsson, M, et al. (författare)
  • Continuous surgical multi-level extrapleural block for video-assisted thoracoscopic surgery: a retrospective study assessing its efficacy as pain relief following lobectomy and wedge resection
  • 2018
  • Ingår i: F1000Research. - : F1000 Research Ltd. - 2046-1402. ; 7, s. 1783-
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Video-assisted thoracoscopic surgery (VATS) causes less postoperative pain than thoracotomy; however, adequate analgesia remains vital. As part of a multi-modal postoperative analgesia, a continuous surgeon-placed extrapleural block catheter is an option. The aim of this retrospective study was to evaluate the analgesic efficacy of a continuous extrapleural block as part of a multimodal analgesic regimen after VATS in general, and VATS lobectomy and wedge resection in particular. Methods: Case records for patients having undergone VATS surgery and been provided a multi-level continuous extrapleural block with an elastomeric pump infusing levobupivacaine 2.7 mg/ml at a rate of 5 ml/h during 2015 and 2016 were reviewed. Pain (Numeric Rating Scale) at rest and mobilisation as well as opioid requirement (daily, postoperative days 0-3, as well as accumulated) were analysed.    Results: In all, 454 records were reviewed: 150 wedge resections, 264 lobectomies and 40 miscellaneous cases. At rest, pain was mild median NRS rated 3-3-1-1 for postoperative day (POD) 0 to 3, during movement, pain was rated moderate during POD 0 and 1 and mild the remaining days (median NRS 4-4-3-3 for POD 0-3). The proportion of patients exhibiting mild pain at rest increased from 55% on POD 0 to 81 % on POD 3. The percentage of patients experiencing severe pain at rest decreased from 15% to 6%. Median oxycodone consumption was 10 mg per day for POD 1-3. Pain after VATS wedge resection was significantly lower at POD 1 and 3 compared to pain after VATS lobectomy. Conclusion: We found a continuous surgeon-placed extrapleural catheter block to be a valuable and seemingly safe addition to our multimodal procedure specific analgesia after VATS. Whether the efficacy of the block can be improved by increasing local anaesthetic and/or adding adjuncts warrants further investigation.
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20.
  • Meraji, Reza, et al. (författare)
  • A 3 mu W 500 kb/s Ultra Low Power Analog Decoder with Digital I/O in 65 nm CMOS
  • 2013
  • Ingår i: 2013 IEEE 20th International Conference on Electronics, Circuits, and Systems (ICECS). - 9781479924523 ; , s. 349-352
  • Konferensbidrag (refereegranskat)abstract
    • Measurement results of an analog channel decoder in 65 nm CMOS are presented. We target ultra compact and low power applications with low to medium throughput requirements. The decoding core is designed for (7,5)(8) convolutional codes and takes 0.104 mm(2) on silicon. The degrading effects of analog imperfections are investigated and the presented results allow power, performance and throughput trade-offs. Analyzing the bit error rate (BER) performance under extreme power constraints provides insights on energy efficiency and limitations of small scale analog decoders. For the limited power budget of 3 W the decoder performs the required computations to provide 1 dB of coding gain at BER=0.001 for 500 kb/s throughput. The presented chip has digital I/O that facilitates embedding it in a conventional digital receiver.
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23.
  • Meraji, Reza, et al. (författare)
  • An Analog (7,5) Convolutional Decoder in 65 nm CMOS for Low Power Wireless Applications
  • 2011
  • Ingår i: [Host publication title missing]. - 2158-1525 .- 0271-4310. - 9781424494736 ; , s. 2881-2884
  • Konferensbidrag (refereegranskat)abstract
    • A complete architecture with transistor level simulation is presented for a low power analog convolutional decoder in 65 nm CMOS. The decoder core operates in the weak inversion (sub-VT) and realizes the BCJR decoding algorithm corresponding to the 4-state tail-biting trellis of a (7,5) convolutional code. The complete decoder also incorporates serial I/O digital interfaces and current mode differential DACs. The simulated bit error rate is presented to illustrate the coding gain compared to an uncoded system. Our results show that a low power, high throughput convolutional decoder up to 1.25 Mb/s can be implemented using analog circuitry with a total power consumption of 84 μW. For low rate applications the decoder consumes only 47 μW at a throughput of 250 kb/s.
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27.
  • Meraji, Reza, et al. (författare)
  • Low power analog channel decoder in sub-threshold 65nm CMOS
  • 2010
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • This paper presents the architecture and the corresponding simulation results for a very low power half-rate extended Hamming (8,4) decoder implemented in analog integrated circuitry. TI’s 65nm low power CMOS design library was used to simulate the complete decoder including an input interface, an analog decoding core and an output interface. The simulated bit error rate (BER) performance of the decoder is presented and compared to the ideal performance expected from the Hamming code. Transistor-level simulation results suggest that a high throughput Hamming decoder up to 1 Mbits can be implemented in analog circuits with a core power consumption as low as 6 μW.
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28.
  • Meraji, Reza, et al. (författare)
  • Transistor sizing for a 4-state current mode analog channel decoder in 65-nm CMOS
  • 2011
  • Ingår i: [Host publication title missing]. - 9781457705144 ; , s. 1-4
  • Konferensbidrag (refereegranskat)abstract
    • Analog decoders are constructed based on interconnecting CMOS Gilbert vector multipliers using transistors operating in the sub-VT region. They are seen as an interesting alternative to digital implementations with a low transistor count and a potential for a very low power consumption. Analog implementation makes the circuit sensitive to mismatch, requiring careful transistor sizing. A simulation technique combining Monte-Carlo analysis in Spectre with Matlab processing has therefore been used to investigate transistor sizing for an analog (7,5) convolutional decoder. The simulation results indicate that with a tail-biting trellis circle size 14 with transistor size W/L = 1.0μm/0.6μm, the decoder can offer close to maximum coding gain while operating on very low currents when implemented in 65-nm CMOS technology.
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30.
  • Sjöland, Henrik, et al. (författare)
  • Ultra low power transceivers for wireless sensors and body area networks
  • 2014
  • Ingår i: 2014 8th International Symposium on Medical Information and Communication Technology (ISMICT). - 2326-828X. - 9781479948567
  • Konferensbidrag (refereegranskat)abstract
    • A transceiver suitable for devices in wireless body area networks is presented. Stringent requirements are imposed by the high link loss between opposite sides of the body, about 85 dB in the 2.45 GHz ISM band. Despite this, minimum physical size and power consumption are required, and we target a transceiver with 1 mm2 chip area, 1 mW active power consumption, and data rate 250 kbit/s. The receiver is fully integrated., fabricated and measured in 65-nm CMOS, and size and power consumption are carefully considered at all levels of circuit and system design. The modulation is frequency shift keying, chosen because transmitters can be realized with high efficiency and low spurious emissions; a modulation index 2 creates a midchannel spectral notch. A direct-conversion receiver achieves minimum power consumption. A tailored demodulation structure makes the digital baseband compact and low power. The channel decoder has been implemented in both analog and digital domains to find the most power efficient solution. Antenna design and wave propagation are studied via simulations with phantoms. The 2.45 GHz ISM band was chosen as a good compromise between antenna size and link loss. An ultra-low power medium access scheme based on a duty-cycled wake-up receiver is designed.
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32.
  • Thorén, Karl, et al. (författare)
  • Precision Issues in the implementation of BCJR decoders
  • 2001
  • Ingår i: [Host publication title missing]. - 0780371232 ; , s. 289-289
  • Konferensbidrag (refereegranskat)abstract
    • The BCJR algorithm is a symbol-bysymbol soft-output MAP decoder for trellis codes. This paper studies the effect of wordlength variations on the BCJR performance and looks at two strategies for reducing the wordlength.
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33.
  • Toller, W, et al. (författare)
  • Preoperative and perioperative use of levosimendan in cardiac surgery: European expert opinion.
  • 2015
  • Ingår i: International Journal of Cardiology. - : Elsevier BV. - 0167-5273 .- 1874-1754. ; 184, s. 323-336
  • Forskningsöversikt (refereegranskat)abstract
    • In cardiac surgery, postoperative low cardiac output has been shown to correlate with increased rates of organ failure and mortality. Catecholamines have been the standard therapy for many years, although they carry substantial risk for adverse cardiac and systemic effects, and have been reported to be associated with increased mortality. On the other hand, the calcium sensitiser and potassium channel opener levosimendan has been shown to improve cardiac function with no imbalance in oxygen consumption, and to have protective effects in other organs. Numerous clinical trials have indicated favourable cardiac and non-cardiac effects of preoperative and perioperative administration of levosimendan. A panel of 27 experts from 18 countries has now reviewed the literature on the use of levosimendan in on-pump and off-pump coronary artery bypass grafting and in heart valve surgery. This panel discussed the published evidence in these various settings, and agreed to vote on a set of questions related to the cardioprotective effects of levosimendan when administered preoperatively, with the purpose of reaching a consensus on which patients could benefit from the preoperative use of levosimendan and in which kind of procedures, and at which doses and timing should levosimendan be administered. Here, we present a systematic review of the literature to report on the completed and ongoing studies on levosimendan, including the newly commenced LEVO-CTS phase III study (NCT02025621), and on the consensus reached on the recommendations proposed for the use of preoperative levosimendan.
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  • Resultat 1-33 av 33

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