Bengt Oelmann
Publications
Articles in journals Chapters in books Conference papers Doctoral theses, monographs Licentiate theses, monographs Reports
Articles in journals
Nazar Ul Islam, M. , Cheng, P. & Oelmann, B. (2015). High performance reference setup for characterization and calibration of low-range differential pressure sensors. IEEE Transactions on Instrumentation and Measurement, vol. 64: 1, pp. 154-162.
Imran, M. , Shahzad, K. , Ahmad, N. , O'Nils, M. , Lawal, N. & Oelmann, B. (2014). Energy Efficient SRAM FPGA based Wireless Vision Sensor Node: SENTIOF‐CAM. IEEE transactions on circuits and systems for video technology (Print), vol. 24: 12, pp. 2132-2143.
Mustafa, M. S. , Cheng, P. & Oelmann, B. (2014). Stator-Free Low Angular Speed Sensor Based on a MEMS Gyroscope. IEEE Transactions on Instrumentation and Measurement, vol. 63: 11, pp. 2591-2598.
Bader, S. , Ma, X. & Oelmann, B. (2014). On the Modeling of Solar-Powered Wireless Sensor Nodes. Journal of Sensor and Actuator Networks, vol. 3: 3, pp. 207-223.
Shahzad, K. , Cheng, P. & Oelmann, B. (2013). Architecture exploration for a high-performance and low-power wireless vibration analyzer. IEEE Sensors Journal, vol. 13: 2, pp. 670-682.
Cheng, P. , Yang, Y. & Oelmann, B. (2012). Design and Implementation of a Stator-Free RPM Sensor Prototype Based on MEMS Accelerometers. IEEE Transactions on Instrumentation and Measurement, vol. 61: 3, pp. 775-785.
Cheng, P. , Sobh, M. & Oelmann, B. (2012). Contactless Rotor RPM Measurement Using Laser Mouse Sensors. IEEE Transactions on Instrumentation and Measurement, vol. 61: 3, pp. 740-748.
Thim, J. , Norlin, B. , O'Nils, M. , Abdalla, S. & Oelmann, B. (2011). Realizing increased sub-pixel spatial resolution in X-ray imaging using displaced multiple images. Nuclear Instruments and Methods in Physics Research Section A, vol. 633: Suppl 1, pp. S247-S249.
Thim, J. , Reza, S. , Nawaz, K. , Norlin, B. , O´Nils, M. & Oelmann, B. (2011). Suitable Post Processing Algorithms for X-Ray Imaging using Oversampled Displaced Multiple Images. Journal of Instrumentation, vol. 6: 2, pp. Art. no. C02001
Cheng, P. , Yang, Y. & Oelmann, B. (2011). Stator-free RPM Sensor Using Accelerometers - A Statistical Performance Simulation by Monte Carlo Method. IEEE Sensors Journal, vol. 11: 12, pp. 3368-3376.
Cheng, P. , Oelmann, B. & Linnarsson, F. (2011). A Local Positioning System for Loader Cranes Based on Wireless Sensors-A Feasibility Study. IEEE Transactions on Instrumentation and Measurement, vol. 60: 8, pp. 2881-2893.
Bader, S. & Oelmann, B. (2011). Durable Solar Energy Harvesting from Limited Ambient Energy Income. International Journal on Advances in Networks and Services, vol. 4: 1&2, pp. 66-80.
Cheng, P. & Oelmann, B. (2010). Joint-angle Measurement Using Accelerometers and Gyroscopes : A Survey. IEEE Transactions on Instrumentation and Measurement, vol. 59: 2, pp. 404-414.
O'Nils, M. , Thim, J. , Norlin, B. & Oelmann, B. (2009). Threshold Modulation for Continuous Energy Resolution with Two Channels per Pixel in a Photon Counting X-ray Image Detector. Nuclear Instruments and Methods in Physics Research Section A, vol. 607: 1, pp. 236-239.
Oelmann, B. & Cao, C. (2008). Low-power state encoding for partitioned FSMs with mixed synchronous/asynchronous state memory. Integration, vol. 41: 1, pp. 123-134.
Aunet, S. , Oelmann, B. , Norseng, P. A. & Berg, Y. (2008). Real-time reconfigurable subthreshold CMOS perceptron. IEEE Transactions on Neural Networks, vol. 19: 4, pp. 645-657.
Lundgren, J. , Abdalla, S. , O'Nils, M. & Oelmann, B. (2007). Power Distribution and Substrate Noise Coupling Investigations on the Behavioral Level for Photon Counting Imaging Readout Circuits. Nuclear Instruments and Methods in Physics Research Section A, vol. 576: 1, pp. 113-117.
Lundgren, J. , O'Nils, M. , Oelmann, B. , Norlin, B. & Abdalla, S. (2007). An Area Efficient Readout Architecture for Photon Counting Color Imaging. Nuclear Instruments and Methods in Physics Research Section A, vol. 576: 1, pp. 132-136.
Lundgren, J. , Abdalla, S. , O'Nils, M. & Oelmann, B. (2006). Evaluation of Mixed-Signal Noise Effects in Photon Counting X-Ray Image Sensor Readout Circuits. Nuclear Instruments and Methods in Physics Research Section A, vol. 563: 1, pp. 88-91.
Cao, C. , O'Nils, M. & Oelmann, B. (2006). Synthesis tool for low-power finite-state machines with mixed synchronous/asynchronous state memory. IEE Proceedings - Computers and digital Techniques, vol. 153: 4, pp. 243-248.
Xue, S. & Oelmann, B. (2006). Unary Prefixed Huffman Coding for a Group of Quantized Generalized Gaussian Sources. IEEE Transactions on Communications, vol. 54: 7, pp. 1164-1169.
Xue, S. & Oelmann, B. (2005). Unary-Prefixed Encoding of the Lengths of Consecutive Zeros in a Bit Vector. Electronics Letters, vol. 41: 6, pp. 346-347.
Xue, S. , Xu, Y. & Oelmann, B. (2003). Hybrid Golomb codes for a group of quantised GG sources. IEE Proceedings - Vision Image and Signal Processing, vol. 150: 4, pp. 256-260.
O'Nils, M. , Abdalla, M. & Oelmann, B. (2002). Low Digital Interference Counter for Photon Counting Pixel Detectors. Nuclear Instruments and Methods in Physics Research, Section A, vol. 487: 3, pp. 323-330.
Oelmann, B. , Abdalla, M. & O'Nils, M. (2002). Robust window discriminator for photon-counting pixel detectors. IEE Proceedings - Optoelectronics, vol. 149: 2, pp. 65-69.
Oelmann, B. , Tammenmäe, K. , Kruus, M. & O'Nils, M. (2001). Automatic FSM synthesis for low-power mixed synchronous/asynchronous implementation. VLSI Design, vol. 12: 2, pp. 167-186.
Oelmann, B. , Abdalla, S. & O'Nils, M. (2001). All-Digital Window Discriminator for Photon Counting Pixel Detectors. Electronics Letters, vol. 37: 6, pp. 373-374.
Shahzad, K. & Oelmann, B. (). Development of an FPGA based high-performance and low-power wireless embedded platform for wireless monitoring applications. Ad Hoc & Sensor Wireless Networks,
Chapters in books
Oelmann, B. & Cao, C. (2007). A Mixed Synchronous/Asynchronous Design Approach for Fine-Grained Dynamic. In Brain Inspired Nano Architectures 2007. World Scientific.
Conference papers
Shahzad, K. & Oelmann, B. (2014). Investigating Energy Consumption of an SRAM-based FPGA for Duty-Cycle Applications. In Advances in parallel computing.. pp. 548--559.
Shahzad, K. & Oelmann, B. (2014). A comparative study of in-sensor processing vs. raw data transmission using ZigBee, BLE and Wi-Fi for data intensive monitoring applications. In 2014 11th International Symposium on Wireless Communications Systems, ISWCS 2014 - Proceedings.. pp. 519--524.
Bader, S. , Krämer, M. & Oelmann, B. (2013). A Domain-Specific Platform for Research in Environmental Wireless Sensor Networks. In SENSORCOMM 2013, The Seventh International Conference on Sensor Technologies and Applications.. pp. 200--207.
Bader, S. & Oelmann, B. (2013). Short-term energy storage for wireless sensor networks using solar energy harvesting. In Networking, Sensing and Control (ICNSC), 2013 10th IEEE International Conference on. (IEEE International Conference on Networking Sensing and Control). pp. 71--76.
Krämer, M. , Bader, S. & Oelmann, B. (2013). Implementing Wireless Sensor Network applications using hierarchical finite state machines. In Networking, Sensing and Control (ICNSC), 2013 10th IEEE International Conference on. (IEEE International Conference on Networking Sensing and Control). pp. 124--129.
Bader, S. & Oelmann, B. (2013). Concealing the complexity of node programming in wireless sensor networks. In Proceedings of the 2013 IEEE 8th International Conference on Intelligent Sensors, Sensor Networks and Information Processing: Sensing the Future, ISSNIP 2013.. pp. 177--182.
Shahzad, K. , Cheng, P. & Oelmann, B. (2013). SENTIOF : An FPGA based high-performance and low-power wireless embedded platform. In 2013 Federated Conference on Computer Science and Information Systems, FedCSIS 2013 : Proceedings.. pp. 901--906.
Shahzad, K. & Oelmann, B. (2013). An FPGA-Based High-Performance Wireless Vibration Analyzer. In NORCHIP 2013.. pp. Art. no. 6702038-
Bader, S. , Oelmann, B. & Brunig, M. (2012). Challenges for RF two-way time-of-flight ranging in wireless sensor networks. In Proceedings - Conference on Local Computer Networks, LCN. (Proceedings - Conference on Local Computer Networks, LCN). pp. 908--916.
Ahmad, N. , Lawal, N. , O'Nils, M. , Oelmann, B. , Imran, M. & Khursheed, K. (2011). Model and placement optimization of a sky surveillance visual sensor network. In Proceedings - 2011 International Conference on Broadband and Wireless Computing, Communication and Applications, BWCCA 2011.. pp. 357--362.
Bader, S. , Anneken, M. , Goldbeck, M. & Oelmann, B. (2011). SAQnet: Experiences from the Design of an Air Pollution Monitoring System Based on Off-the-Shelf Equipment. In Proceedings of the 2011 7th International Conference on Intelligent Sensors, Sensor Networks and Information Processing, ISSNIP 2011.. pp. 223--228.
Bader, S. , Schölzel, T. & Oelmann, B. (2010). A Method for Dimensioning Micro-Scale Solar Energy HarvestingSystems Based on Energy Level Simulations. In Proceedings - IEEE/IFIP International Conference on Embedded and Ubiquitous Computing, EUC 2010.. pp. 372--379.
Wang, X. , Rödjegård, H. , Oelmann, B. , Martin, H. & Larsson, B. (2010). High performance CO2 measurement based on pressure modulation. In Proceedings of 24th Eurosensors Conference. (Procedia Engineering). pp. 1208--1211.
Bader, S. & Oelmann, B. (2010). Enabling battery-less wireless sensor operation using solar energy harvesting at locations with limited solar radiation. In Proceedings - 4th International Conference on Sensor Technologies and Applications, SENSORCOMM 2010.. pp. 602--608.
Thim, J. , Norlin, B. , O'Nils, M. , Abdalla, S. & Oelmann, B. (2009). Realizing increased sub-pixel spatial resolution in X-ray imaging using displaced multiple images. In 11th International Workshop on Radiation Imaging Detectors.
Bader, S. & Oelmann, B. (2009). Adaptive synchronization for duty-cycling in environmental wireless sensor networks. In ISSNIP 2009 - Proceedings of 2009 5th International Conference on Intelligent Sensors, Sensor Networks and Information Processing.. pp. 49--54.
Linnarsson, F. , Cheng, P. & Oelmann, B. (2008). A Power Aware MAC protocol for Wireless Closed Loop Control System in Loader Cranes. In 2008 IEEE INTERNATIONAL SYMPOSIUM ON INDUSTRIAL ELECTRONICS, VOLS 1-5. New York : . pp. 1806--1811.
Abdalla, S. , Oelmann, B. , O'Nils, M. & Thim [Lundgren], J. (2007). Architecture and Circuit Design for Color X-Ray Pixal Array Detector Read-Out Electronics. In Proceedings of the IEEE Norchip Conference 2007. New York : . pp. 271--276.
Alfredsson, J. , Aunet, S. & Oelmann, B. (2007). Small Fan-in Floating-gate Circuits with Application to an Improved Adder Structure. In 20TH INTERNATIONAL CONFERENCE ON VLSI DESIGN, PROCEEDINGS - TECHNOLOGY CHALLENGES IN THE NANOELECTRONICS ERA. (International Conference on VLSI Design, Proceedings). pp. 314--317.
Cheng, P. , Linnarsson, F. & Oelmann, B. (2007). Joint Angular Sensor Based on Distributed Biaxial MEMS Accelerometers. In IECON 2007: 33RD ANNUAL CONFERENCE OF THE IEEE INDUSTRIAL ELECTRONICS SOCIETY, VOLS 1-3, CONFERENCE PROCEEDINGS. New York : (IEEE Industrial Electronics Society). pp. 2242--2247.
Unander, T. , Nilsson, H. & Oelmann, B. (2007). Printed touch sensor for interactive packaging and display. In Polytronic 2007 : the 6th International IEEE Conference on Polymers and Adhesives in Microelectronics and Photonics.. pp. 12--17.
Cao, C. & Oelmann, B. (2007). The Analysis of Power-Related Characteristics of FSM Benchmarks. In 2007 50TH MIDWEST SYMPOSIUM ON CIRCUITS AND SYSTEMS, VOLS 1-3. New York : (Midwest Symposium on Circuits and Systems Conference Proceedings). pp. 787--790.
Linnarsson, F. , Cheng, P. & Oelmann, B. (2007). Analysis of the IEEE 802.15.4 Standard for a Wireless Closed Loop Control System for Heavy Duty Cranes. In 2007 INTERNATIONAL SYMPOSIUM ON INDUSTRIAL EMBEDDED SYSTEMS - SIES'2007.. pp. 164--169.
Alfredsson, J. & Oelmann, B. (2006). Influence of Refresh Circuits Connected to Low Power Digital Quasi-Floating gate Designs. In 2006 13TH IEEE INTERNATIONAL CONFERENCE ON ELECTRONICS, CIRCUITS AND SYSTEMS, VOLS 1-3.. pp. 1296--1299.
Cao, C. & Oelmann, B. (2006). Area-Power Trade-Off in FSM Partitioning. In International conference on signals and electronic systems. Conference proceedings, 17-20 sept. 2006, Lodz, Poland.. pp. 349--352.
Alfredsson, J. & Oelmann, B. (2006). Capacitance Selection for Digital Floating Gate Circuits Operating in Subthreshold. In 2006 IEEE INTERNATIONAL SYMPOSIUM ON CIRCUITS AND SYSTEMS, VOLS 1-11, PROCEEDINGS. (IEEE INTERNATIONAL SYMP ON CIRCUITS AND SYSTEMS). pp. 4341--4344.
Linnarsson, F. , Cheng, P. & Oelmann, B. (2006). SENTIO: A. Hardware Platform for Rapid Prototyping of Wireless Sensor Networks. In IECON 2006 - 32ND ANNUAL CONFERENCE ON IEEE INDUSTRIAL ELECTRONICS, VOLS 1-11. (IEEE Industrial Electronics Society). pp. 2243--2247.
Abdalla, S. , Nilsson, H. & Oelmann, B. (2005). Circuit Implementation of Mechanism for Charge-Sharing Suppression for Photon-Counting Pixel Arrays. In Norchip 2005, Proceedings.. pp. 137--140.
O'Nils, M. , Oelmann, B. , Bertilsson, K. , Nilsson, H. & Thungström, G. (2005). A Project Based Master's Program for SoF/SoC based Sensor Systems. In Proceedings of the European Conference on Circuit Theory and Design.
Alfredsson, J. , Aunet, S. & Oelmann, B. (2005). Basic Speed and Power Properties of Digital Floating-gate Circuits Operating in Subthreshold. In Proceedings of IFIP VLSI-SOC 2005 : International Conference on Very Large Scale Integration.. pp. 229--232.
Mårtensson, P. , Persson, J. , Xue, S. & Oelmann, B. (2005). Efficient Decoding of Variable Length Endoded Image Data on the Nios II Soft-Core Processor. In Proceedings of the International Workshop on Applied Reconfigurable Computing, Algarve, Portugal, February 2005.
Oelmann, B. , Linnarsson, F. , Aunet, S. & Berg, Y. (2004). Experimental Setup for UV-Programming of Floating-Gate MOS Circuits. In Proceedings of IEEE International Conference on Signals and Electronic Systems.
Aunet, S. , Oelmann, B. , Abdalla, S. & Berg, Y. (2004). Reconfigurable Subthreshold CMOS Perceptron. In IEEE International Joint Conference on Neural Networks 2004.
Cao, C. & Oelmann, B. (2004). Mixed Synchronous/Asynchronous State Memory for Low Power FSM Design. In Proceedings of EUROMICRO Symposium on Digital System Design.. pp. 363--370.
Oelmann, B. & O'Nils, M. (2004). A Course in Basic Digital Electronics for a Distance Educational Programme. In Proceedings of IEEE International Conference on Signals and Electronic Systems.
Alfredsson, J. & Oelmann, B. (2004). Trading Speed and Power for Reduced Substrate Noise from Digital CMOS Circuits. In Proceedings of IEEE International Conference on Signals and Electronic Systems. Poznan, Poland :
Cao, C. , O'Nils, M. & Oelmann, B. (2004). A Tool for Low-Power Synthesis of FSMs with Mixed Synchronous/Asynchronous State Memory. In 22ND NORCHIP CONFERENCE, PROCEEDINGS.. pp. 199--202.
Aunet, S. & Oelmann, B. (2004). 200 mV Full Adder Based on a Reconfigurable CMOS Perceptron. In Proceedings of IEEE International Conference on Signals and Electronic Systems.
Aunet, S. , Oelmann, B. , Lande, T. & Yngvar, B. (2004). Multifunction Subthreshold Gate used for a Low Power Full Adder. In Proceedings of the IEEE Norchip Conference.
Lundgren, J. , Oelmann, B. , Ytterdal, T. , Eriksson, P. , Abdalla, M. & O'Nils, M. (2003). A power-line noise coupling estimation methodology for architectural exploration of mixed-signal systems. In Proceedings of the Southwest Symposium on Mixed-Signa Design.. pp. 133--137.
O´Nils, M. , Lundgren, J. & Oelmann, B. (2003). A SystemC Extension for Behavioral Level Quantification of Noise-Coupling in Mixed-Signal Systems. In PROCEEDINGS OF THE 2003 IEEE INTERNATIONAL SYMPOSIUM ON CIRCUITS AND SYSTEMS, VOL III - GENERAL & NONLINEAR CIRCUITS AND SYSTEMS Vol 3.. pp. 898--901.
Linnarsson, F. , Aunet, S. & Oelmann, B. (2003). A Static Single-Phase D-latch for UV-Programmable Floating-Gate MOSFET Circuits. .
Lundgren, J. , Oelmann, B. , Ytterdal, T. , Eriksson, P. , Abdalla, M. & O´Nils, M. (2003). Behavioral Simulation of Power Line Noise Coupling in Mixed-Signal Systems using SystemC. In ISVLSI 2003: IEEE COMPUTER SOCIETY ANNUAL SYMPOSIUM ON VLSI, PROCEEDINGS - NEW TRENDS AND TECHNOLOGIES FOR VLSI SYSTEMS DESIGN.. pp. 275--277.
Xue, S. & Oelmann, B. (2003). Efficient VLSI Implementation of a VLC Decoder for Universal Variable Length Code using Alternating Coding. In ISVLSI 2003: IEEE COMPUTER SOCIETY ANNUAL SYMPOSIUM ON VLSI, PROCEEDINGS - NEW TRENDS AND TECHNOLOGIES FOR VLSI SYSTEMS DESIGN.. pp. 207--208.
Xue, S. & Oelmann, B. (2003). Efficient VLSI Implementation of a VLC Decoder for Golomb-Rice Code using Alternating Coding. In IEEE Norchip´03, Riga, Latvia, November 2003.
Xue, S. & Oelmann, B. (2003). Parallel Variable-length Decoder Architecture for Alternated Coded GR-Codes. In IEEE Norchip´03, Riga, latvia, november, 2003.
Xue, S. & Oelmann, B. (2003). Error Resilient coding of DCT coefficients using alternating coding of UVLC. In Norsig, Bergen, Norway, October 2003.
Xue, S. & Oelmann, B. (2003). A Coding Method for UVLC Targeting Efficient Decoder Architecture. In Proceedings of the 3rd IEEE Internatioal Symposium on Image and Signal Processing and Analysis, Rome, Italy, September, 2003.. pp. 428--433.
Xue, S. & Oelmann, B. (2003). Alternating Coding for Universal Variable Length Code. In Procceedings of the IEEE International Conference on Image Processing, Barcelona, Spain, September, 2003.. pp. 477--480.
Xue, S. & Oelmann, B. (2001). Comparative study of low-voltage performance of standard-cell flip-flops. In ICECS 2001 : 8TH IEEE INTERNATIONAL CONFERENCE ON ELECTRONICS, CIRCUITS AND SYSTEMS, VOLS I-III, CONFERENCE PROCEEDINGS. New York : . pp. 953--957.
O'Nils, M. & Oelmann, B. (2000). Using CoWare in a Course on Design of Embedded HW/SW System. In Proceedings of the 18th IEEE Norchip Conference.
Norell, H. , O'Nils, M. & Oelmann, B. (2000). Requirement Analysis of Reconfigurable Hardware Prototyping Platforms for Development of Real-Time Video Applications. In Proceedings of 18th IEEE Norchip Conference.
Norell, H. , Oelmann, B. & Xu, Y. (2000). Spatio-Temporal Noise Reduction algorithm targeting Real-Time Video Processing. In Proceedings of IEEE International Symposium on Information Theory and Its Applications 2000.
Norell, H. , Oelmann, B. & Xu, Y. (2000). Spatio-Temporal Noise Reduction ASIC for Real-Time Noise Reduction ASIC Processing. In Proceedings of 2000 IEEE Nordic Signal Processing Symposium.
Oelmann, B. , Norell, H. , Andersson, R. & Xu, Y. (1999). Design of Real-Time Signal Processing ASIC for Noise Reduction In Moving Video Images. In Proceedings of the 17th IEEE Norchip conference.
Oelmann, B. & O'Nils, M. (1999). LIFS: A Tool for Low-Power Implementation of FSMs. In Proceedings of the 17th IEEE Norchip Conference.
Oelmann, B. & O'Nils, M. (1999). Asynchronous Control of Low-Power Gated-Clock Finite-State Machines. In Proceedings of IEEE International Conference on Electronics, Circuits and Systems.
Oelmann, B. & O'Nils, M. (1999). A Low Power Hand-Over Mechanism for Gated-Clock FSMs. In Proceedings of the European Conference on Circuit Theory and Design.
Pasanen, J. & Oelmann, B. (1999). Locally clocked AFSMs using dynamic latch implementation. In Electronics, Circuits and Systems, 1999. Proceedings of ICECS '99. The 6th IEEE International Conference on : Vol 3.. pp. 1643--1646.
Oelmann, B. & Tenhunen, H. (1996). Micropipeline DSP-ASIC for DS-SS receiver. .
Oelmann, B. , Martijn, H. & Tenhunen, H. (1996). An asynchronous implementation of a DS-SS radio receiver. .
Oelmann, B. & Tenhunen, H. (1996). A system level performance model for asynchronous micropipeline circuits. .
Oelmann, B. , Olsson, H. , Kerek, D. & Tenhunen, H. (1996). Differential PSK detector design for direct sequence spread spectrum radio. .
Oelmann, B. & Tenhunen, H. (1995). Comparison of self-timed and synchronous high-speed VLSI/ULSI circuits using system level performance modelling. .
Oelmann, B. , Martijn, H. & Tenhunen, H. (1995). Design of an asynchronous macro-cell library. .
Oelmann, B. , Martijn, H. & Tenhunen, H. (1995). Design of an asynchronous direct sequence spread spectrum digital radio receiver. .
Shahzad, K. & Oelmann, B. (). Quantitative Evaluation of an FPGA based Wireless Vibration Monitoring System in relation to Different Sampling Rates. .
Doctoral theses, monographs
Oelmann, B. (2000). Asynchronous and Mixed Synchronous/Asynchronous Design Techniques for Low Power. Dis. , 2000 (Trita-ESD : 0006)
Licentiate theses, monographs
Oelmann, B. (1996). Design and Performance Evaluation of Asynchronous Micropipeline Circuits for Digital Radio. Lic. , 1996 (Trita-ESD : 9608)
Reports
Oelmann, B. , O'Nils, M. , Tammemäe, K. , Kruus, M. & Tenhunen, H. (2000). Automatic FSM synthesis for low-power mixed synchronous/asynchronous implementation.