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Annual Report 2013

Table of Contents
Introduction ................................................................................................................................ i
BWRC Faculty & Scientific Directors...................................................................................... v
Theme Reports
RF and mm-Wave ................................................................................................................... 1
Biomedical Systems .............................................................................................................. 21
Energy Efficient Systems ....................................................................................................... 35
Extreme Circuits .................................................................................................................... 55
UnPad and eWallpaper......................................................................................................... 67
Advanced Spectrum Utilization .............................................................................................. 77
Integrated Wireless Systems and Applications ...................................................................... 85
Recent Publications ................................................................................................................ 98
Acknowledgements .............................................................................................................. 105
BWRC Staff ............................................................................................................................ 109

BWRC Students
Theme Reports
RF and mm-Wave ...................................................................................................................................................... 1
Ashkan Borna ................................................................................................................................................. 3
Lucas Calderin ................................................................................................................................................ 4
Jia-Shu Chen .................................................................................................................................................. 5
Dajana Danilovic ............................................................................................................................................. 6
Shinwon Kang .................................................................................................................................................. 7
Lingkai Kong ................................................................................................................................................... 8
Nai-Chung Kuo ................................................................................................................................................ 9
Amanda Pratt ................................................................................................................................................ 10
Paul Swirhun .................................................................................................................................................. 11
Maryam Tabesh ............................................................................................................................................. 12
Chintan Thakkar ........................................................................................................................................... 13
Siva Thyagarajan ........................................................................................................................................... 14
Andrew Townley ............................................................................................................................................ 15
Angie Wang .................................................................................................................................................. 16
Chaoying Wu ................................................................................................................................................ 17
Bonjern Yang ................................................................................................................................................ 18
Lu Ye ............................................................................................................................................................. 19
Biomedical Systems................................................................................................................................................. 21
William Biederman ......................................................................................................................................... 23
Jun-Chau Chien ............................................................................................................................................. 24
Ping-Chen Huang .......................................................................................................................................... 25
Jaclyn Leverett .............................................................................................................................................. 26
Wen Li ............................................................................................................................................................ 27
Filip Maksimovic ........................................................................................................................................... 28
Rikky Muller ................................................................................................................................................... 29
Nathan Narevsky ........................................................................................................................................... 30
DJ Seo ........................................................................................................................................................... 31
Christopher Sutardja ...................................................................................................................................... 32
Dan Yeager .................................................................................................................................................... 33
Energy Efficient Systems ......................................................................................................................................... 35
Steven Bailey ................................................................................................................................................ 37
Jethro Beekman ............................................................................................................................................ 38
Milovan Blagojevic ........................................................................................................................................ 39
Pi-Feng Chiu .................................................................................................................................................. 40
Ruzica Jevtic ................................................................................................................................................. 41
Mervin John .................................................................................................................................................. 42
Benjamin Keller ............................................................................................................................................. 43
Nam-Seog Kim .............................................................................................................................................. 44
Jaehwa Kwak ................................................................................................................................................. 45
Hanh-Phuc Le ................................................................................................................................................ 46

Pengpeng Lu ................................................................................................................................................ 47
Hoai Chau Nguyen Van ................................................................................................................................. 48
Jesse Richmond ............................................................................................................................................ 49
Nicholas Sutardja .......................................................................................................................................... 50
Stephen Twigg ............................................................................................................................................... 51
Wenting Zhou ................................................................................................................................................ 52
Brian Zimmer ................................................................................................................................................. 53
Extreme Circuits ...................................................................................................................................................... 55
Steven Callender ........................................................................................................................................... 57
John Crossley ................................................................................................................................................ 58
Yida Duan ...................................................................................................................................................... 59
Jaeduk Han .................................................................................................................................................... 60
Rachel Hochman ........................................................................................................................................... 61
Kwangmo Jung .............................................................................................................................................. 62
Yue Lu ........................................................................................................................................................... 63
Rachel Nancollas ........................................................................................................................................... 64
Aikaterini Papadopoulou ................................................................................................................................ 65
Matthew Spencer ........................................................................................................................................... 66
UnPad and eWallpaper ........................................................................................................................................... 67
Shaoyi Cheng ................................................................................................................................................ 69
Terry Filiba ..................................................................................................................................................... 70
Greg Gibeling ................................................................................................................................................. 71
Alexander Krasnov ........................................................................................................................................ 72
Hao Liu .......................................................................................................................................................... 73
James Martin ................................................................................................................................................. 74
Simon Scott ................................................................................................................................................... 75
Advanced Spectrum Utilization ................................................................................................................................ 77
Milos Jorgovanovic ........................................................................................................................................ 79
Arash Parsa ................................................................................................................................................... 80
Sameet Ramakrishnan .................................................................................................................................. 81
Matthew Weiner ............................................................................................................................................. 82
Sharon Xiao ................................................................................................................................................... 83
Integrated Wireless Systems and Applications ........................................................................................................ 85
Jayme Keist ................................................................................................................................................... 87
Deepa Madan ................................................................................................................................................ 88
Peter Minor .................................................................................................................................................... 89
Christopher Sherman ..................................................................................................................................... 90
Adam Tornheim ............................................................................................................................................. 91
Jason Trager .................................................................................................................................................. 92
Zuoqian Wang ............................................................................................................................................... 93
Andrew Waterbury ......................................................................................................................................... 94
Rich Winslow ................................................................................................................................................. 95
Qiliang (Richard) Xu....................................................................................................................................... 96

INTRODUCTION
Ken Lutz, Technical Director
Berkeley Wireless Research Center
The Berkeley Wireless Research Center (BWRC), now in its second decade, is a partnership of UCB
researchers, leading electronics companies, and government research agencies. The mission of BWRC is
to educate world class researchers while exploring the leading edge of knowledge in future generations of
technology for wireless communications systems. BWRC addresses the design, conception, and
implementation of the next-generation integrated wireless systems in state-of-the-art CMOS (and related)
technologies. Our focus is on the integrated circuits and systems advances needed to enable a vision of
truly ubiquitous wireless, including the realization of always-connected reliable networks through
advanced spectrum utilization techniques, the design of energy-efficient high data-rate links at 60 GHz
and above, the investigation of the boundaries of ultra-low-energy wireless networks, and the exploration
of the leading edge circuit techniques and components that make these systems possible.
Faculty and students at BWRC collaborate in communication theory with the Berkeley Wireless
Foundations Center, in MEMS technology with the Berkeley Sensor and Actuator Center (BSAC), and in
applications for biomedical and environmental engineering with the Center for Information Technology
Research in the Interest of Society (CITRIS) and the UCSF Medical School. This critical-mass
combination of UC Berkeley researchers, leading corporate sponsors and government funding agencies
continues to deliver in making truly significant advances possible as demonstrated by the Centers’ impact
in the areas of millimeter-wave radio, cognitive radio, ultra wideband and ultra-low power wireless
systems.
As you will see from this annual report, 2012 has been an exciting year at BWRC. Significant progress
has been made across all areas of research and several new initiatives, including the eWallpaper, have
moved forward.
The following section provides a brief introduction and update to the seven research themes of the
Berkeley Wireless Research Center
1. RF and mm-Wave
The aim of this group is to design and implement highly-integrated RF and mm-wave transceivers using
conventional silicon technology. The group consists of circuit designers who interact with system
engineers to design energy efficient communication and imaging systems. Our current focus is on
expanding the potential application space for low-cost mm-wave CMOS circuits and SoCs. Projects
include high efficiency power amplifiers and transmitters, both for RF and mm-wave applications. These
transmitters incorporate mixed signal and digital techniques to enhance the efficiency using an RF power
DAC, oversampling and digital spectral image filtering. On the receiver side the focus is on improving
the linearity of amplifiers and mixers to enable SAWless operation for multi-standard and reconfigurable
front-ends. We are also exploring the application of mm-waves for wireless chip-to-chip communication.
A 240 GHz prototype is developed to provide high data rates (> 10 Gbps) with low power consumption
(< 50pJ/bit). Work in imaging includes the Time-domain UWB Synthetic Imager (TUSI) for medical
applications and mm-Wave RFID.
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Operating at mm-wave frequencies using technologies with lossy substrates requires novel circuit design
techniques as well as accurate high-frequency modeling of active and passive devices. Also, new system
design methodologies will be needed to account for the limited performance of CMOS microwave circuits
up to 300 GHz along with the huge amounts of available bandwidth. To accomplish this goal, our group
combines Berkeley's traditional expertise on integrated circuit design, device modeling, and system
design with the state-of-the-art silicon technologies and vast experience with mm-wave circuit design
provided by the BWRC industrial partners.
2. Biomedical Systems
Advancements in systems and circuits miniaturization and energy reduction allow for an ever-tighter
interfacing between the biological and the cyber world. It is not too far-fetched to imagine integrated
sensor (actuator) nodes, including data acquisition and processing circuitry as well as data transmission,
that approach the size of a biological cell. This opens the door for a broad range of exciting new
applications in the biomedical space. Examples include advanced in-situ and in-vivo monitoring and
diagnostics, as well as stimulation or actuation. Mobility, longevity and reliability concerns demand that
these nodes communicate wirelessly and operate in energy self-contained mode for a long period of time
(> 10 years in some cases). The Berkeley Wireless Research Center (BWRC), with its long-established
expertise in energy-efficient circuit design for processing and communication, as well as in energyharvesting
technologies, is therefore at the forefront of the development of the most advanced miniature
biomedical systems. An example is its work in brain-machine interfaces (the ultimate unPad technology),
in collaboration with the UCB-UCSF Center for Neural Engineering and Prosthetics (CNEP).
Wireless technologies, besides offering the capability of data communication and power delivery, also
play an increasing role in medical imaging applications using the penetrating capabilities of highfrequency
electromagnetic waveforms. BWRC has been a pioneer in the domain of millimeter-wave and
TeraHertz transceivers, implemented in standard CMOS technologies. Advancing the state-of-the-art in
CMOS electromagnetic imaging is the target of a range of projects at the Center, essential to the success
of the tight integration of antennas, passives and active circuitry into single CMOS devices.
3. Energy Efficient Systems
Wireless systems are evolving to a three tiered environment with a ubiquitous, embedded and transparent
sensory swarm at the outer layer. Ultra-low-power realizations of integrated wireless sensor nodes are an
essential condition for the swarm concept to become truly successful. This research effort explores the
boundaries of low-power design, seeking new design paradigms to enable both major power/energy
reduction as well as continuing miniaturization. These reductions in size and energy can only be realized
by a combination of innovative approaches, including novel technologies such as NEMS relays and
oscillators; ultra-low-voltage scaled CMOS design; and alternative architectures for RF, mixed-signal and
digital components.
Energy scavenging and storage are critical enabling technologies for energy self-sufficient systems.
Wireless power transmission and photovoltaic power harvesting are the most commonly explored
techniques today, but other energy sources such as Vibrations, Air Flow, Temperature Gradients, Pressure
Gradients and Human Power are being explored as well. For implantable devices, glucose biofuel cells
are an interesting option worth investigating.
To push the limits, we have selected a number of advanced applications that would not be possible
without major advances in low-power design technology. Among these are integrated bio-medical health
management systems including sensors for neural implantation to enable brain-machine interfaces, energy
self-contained sensor tags for body-area networking, wake-up radios, and sensor nets for smart energy
systems.
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4. Extreme Circuits
Existing as well as evolving applications along with the integrated systems that enable them continue to
require significant advances in their underlying circuit implementation. However, as CMOS scaling has
shifted into a regime where most of the device parameters do not significantly improve with
miniaturization, realizing these circuit advances has become increasingly difficult to achieve. Our goal is
thus to address these challenges by developing techniques that push the extremes of circuit performance,
energy, and robustness, fueling the continued growth of IC applications.
Given the many different functions integrated into modern ICs, researchers within this group focus on a
variety of building blocks and their associated design methodologies, including digital computing and
signal processing circuits, high-speed serial transceivers, RF components, memories, data converters,
clock generation and synthesis circuits, and integrated voltage regulators. Furthermore, researchers are
developing design methodologies and frameworks enabling the capture and automatic re-use (resulting in
complete designs including schematics and layout) of the methodologies we have developed. In order to
evaluate our techniques in the most realistic environment possible, many of the concepts developed
within the group are demonstrated in some of the most advanced CMOS processes available (including
45, 32 and 22nm FDSOI). To push the boundaries even further, our group is also exploring circuit designs
exploiting the properties of next-generation and alternative switching devices such as FinFETs, spinbased
transistors, and nano-mechanical relays.
5. UnPad and eWallpaper
The unPad is a vision of the future where pads and other handheld devices cease to be necessary. The pad
disappears, but its functionality (plus more) stays—in the form of unpackaged communication,
computation, and storage. People seamlessly interact with data, the environment and one another through
an interconnected set of sensor, actuators, and computing and storage devices. Sensors and actuators in
the environment are used as input/output devices, and along with computing, storage, and communication
bandwidth, will be commissioned on the fly as needed to provide the desired functionality. As a person
moves through their environment, say from home to car and then to their office, a set of their data moves
with them, and the sensors and actuators in whatever environment they happen to occupy are clustered in
an ad hoc way to support whatever services are currently needed. This strong sense of seamless mobility,
and the opportunistic assembly and allocation of resources is what has been missing in earlier similar
visions such as ubiquitous computing. Our research at BWRC forms the basis of what is needed to fulfill
the unPad vision.
The unPad vision presents many technical challenges. We envision an infrastructure that dynamically
matches the needs of the user to available resources, thus creating a “virtual device”. Such a vision is a
significant deviation from current wireless systems networking in terms of data streaming and control.
Discovery plays a key role, as does the need to continuously bundle local functionality in creating
services. The infrastructure must exploit locality to maximize total system communication capacity and
minimize energy consumption. The dynamic configuration requires sophisticated resource management
and policies for conflict resolution. We envision a hierarchical wireless region-based model: from the
human-body level, to the room, to the building, to an entire block, etc. However, this clustering would be
dynamically changing, as a person's spatial domain of interest changes. In some cases the domains will
be “virtual” instead of physical, to handle long-distance communication modes such as tele-presence.
Peer-to-peer connections within zone (similar to WiFi Direct or FlashLinq) will be used. Whenever
present, the fixed wired infrastructure can be a complement to wireless.
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6. Advanced Spectrum Utilization
The goal of this group is to fundamentally change the operation of wireless communication systems.
Explosive growth of wireless communications over the last decade and reliance on mobile telephones for
daily voice and data communication, and often for first contact in case of emergency, has become
pervasive. Present methods of frequency allocation combined with a reliance on rigid infrastructure
threaten to halt this growth. By enabling secondary use of spectrum on an opportunistic basis, ubiquitous,
robust and agile wireless systems can be realized that are able to support further traffic growth. As such, it
will enable the extension of wireless data-rates and coverage for many decades to come and open the door
for exciting new applications to emerge.
This set of projects will lay the theoretical foundation, develop the necessary systems knowledge and
demonstrate prototype test beds for a new kind of a wireless system, which will operate in a very broad
frequency spectrum with bands of operation that can be dynamically allocated. Additionally, this group
will investigate methods for optimal use of spatial diversity to enable continued capacity growth of
wireless systems by operating at the limits of available multiplexing and diversity gains. One of the
concepts that would enable the reuse of frequency bands is a Connectivity Broker—an agent embedded in
the wireless infrastructure that communicates over a virtual control channel—to support diversity of radio
technologies as well as innovative rules of cooperation. The concept of secondary use of the spectrum in
combination with advanced cooperation between system components is revolutionary, and it is enabled by
advances in fundamental communications and networking theory and continued improvements in
integrated circuit technology.
7. Integrated Wireless Systems and Applications
High-value products such as aerospace engines and semiconductor fabrication equipment will continue to
expand in sophistication and include even more sensing and closed-loop control. The trend towards the
deployment of wireless sensor nodes and networks (WSNs) will continue due to lower cost and flexibility
of such systems. As a result, the many sub-assemblies of these high-value products will be densely
packed with wireless sensor nodes for the purpose of fine-grained monitoring over the whole lifetime of
the product. Even modestly complex products such as the pumps and motors in the cooling/air cleaning
systems of a semiconductor fab need better monitoring than is common today. Better monitoring and
sustainment efforts can be achieved with condition–based monitoring platforms that combine energy
harvesting, energy storage, sensors, and wireless communication. Condition monitoring research extends
beyond industrial machinery and currently includes societal infrastructure associated with the smart grid,
water, and gas pipelines. To enable this research, an adaptable wireless node architecture has been
developed around the Texas Instruments eZ430-RF2500 wireless development platform. The node can be
configured to accept harvested energy from the inherent mechanical vibrations of industrial machinery,
AC energized conductors, or a battery. The standard node configuration includes a digital accelerometer
and pressure sensor, but it can accept additional sensor inputs as well. Independent research continues on
energy harvesting, energy storage, sensors (current, voltage, pressure), and condition monitoring, but each
research component can be combined, tested, and realistically deployed using the adaptable node
architecture based on the TI eZ430-RF2500 wireless development platform. These research condition
monitoring nodes combining the various technologies are currently being deployed on industrial
machinery and gas pipelines to collect data that will enable mapping of the unique signatures of specific
machine or infrastructure failures.
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BWRC FACULTY & SCIENTIFIC DIRECTORS
Elad Alon
Associate Professor of Electrical Engineering and Computer
Sciences
E-mail: elad@berkeley.edu
Research Web Page: http://www.eecs.berkeley.edu/~elad
Professor Alon received the B.S., M.S., and Ph.D. degrees in
Electrical Engineering from Stanford University. He joined the
faculty at the University of California, Berkeley in January 2007.
He has held visiting positions at Cadence, Xilinx, Oracle Labs,
Intel, AMD, Rambus, HP, and IBM, where he worked on digital,
analog, and mixed-signal integrated circuits for computing, test and
measurement, and high-speed communications. His research
interests are in energy-efficient integrated systems, including the
circuit, device, and optimization techniques used to design them.
Bob Brodersen
Professor Emeritus of Electrical Engineering and Computer
Sciences
E-mail: rb@eecs.berkeley.edu
Research Web Page:
http://bwrc.eecs.berkeley.edu/People/Faculty/rb/
A pioneer in the field of computer speech recognition and a leading
authority in wireless communication. Professor Brodersen received
his Ph.D. from MIT in 1976 and was associated with the Central
Research Laboratory, Texas Instruments until 1976, when he
joined the EECS faculty at the University of California, Berkeley.
A member of the National Academy of Engineering, his research
interests include communication systems, signal processing and
design, layout, simulation, and testing of integrated circuits.
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Ali M. Niknejad
Professor of Electrical Engineering and Computer Sciences
E-mail: niknejad@eecs.berkeley.edu
Research Web Page: http://rfic.eecs.berkeley.edu/~niknejad/
Professor Ali M. Niknejad received the B.S.E.E. degree from the
University of California, Los Angeles, in 1994, and his Master’s
and Ph.D. degrees in electrical engineering from the University of
California, Berkeley, in 1997 and 2000. He is currently a professor
in the EECS department at UC Berkeley and co-director of the
Berkeley Wireless Research Center and the BSIM Research
Group. His research interests lie within the area of RF, mm-wave,
and sub-THz for applications in medicine and wireless
communications. Prof. Niknejad is an IEEE Fellow and recipient
of the 2012 ASEE Frederick Emmons Terman Award.
Borivoje Nikolić
Professor of Electrical Engineering and Computer Sciences
E-mail: bora@eecs.berkeley.edu
Research Web Page: http://www.eecs.berkeley.edu/~bora/
Professor Nikolić has main interests in the implementation of
communications circuits and systems. He received his Dipl. Ing
and M.Sc. degrees in Electrical Engineering from the University of
Belgrade, Yugoslavia in 1992 and 1994, respectively. He received
a Ph.D. degree in Electrical and Computer Engineering from the
University of California, Davis in 1999. Before coming to
Berkeley, he had appointments as a lecturer at the University of
Belgrade and with Silicon Systems, Inc., Texas Instruments
Storage Products Group, San Jose, CA, where he worked on disk
drive signal processing electronics.
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Jan Rabaey
Donald O. Pederson Distinguished Professor
of Electrical Engineering and Computer Sciences
Director of Multiscale Systems Center (MuSyC)
E-mail: jan@eecs.berkeley.edu
Research Web Page:
http://bwrc.eecs.berkeley.edu/People/Faculty/jan/
Professor Rabaey is a leader in the domains of low power design
technologies and methodologies. After receiving his Ph.D. degree
in Applied Sciences from the Katholieke Universiteit Leuven,
Belgium in 1983, he joined the University of California, Berkeley
as a Visiting Research Engineer. From 1985 to1987 he was a
research manager at IMEC, Belgium, and in 1987 he joined the
faculty of the Electrical Engineering and Computer Science
department of the University of California, Berkeley. From 1999
until 2002, he was the Associate Chair of the EECS department at
UC Berkeley. He is the past director of the FCRP Gigascale
Systems Research Center (GSRC) and the current director of the
FCRP Multiscale Systems Center (MuSyC). An IEEE Fellow and
recipient of the 2008 IEEE CAS Mac Van Valkenburg, the 2009
EDAA Lifetime Achievement and the 2010 Semiconductor
Industry Association University Researcher Awards, his current
research interests include the conception and design of nextgeneration
wireless systems with a special focus on ubiquitous
distributed systems.
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John Wawrzynek
Professor of Electrical Engineering and Computer Sciences
E-mail: johnw@eecs.berkeley.edu
Research Web Page: http://www.cs.berkeley.edu/~johnw/
Dr. John Wawrzynek is a Professor of Electrical Engineering and
Computer Sciences at the University of California, Berkeley. He
holds a Ph.D. and M.S. in Computer Science from the California
Institute of Technology, an M.S. in Electrical Engineering from the
University of Illinois, Urbana/Champaign, and a BS in Electrical
Engineering, from the State University of New York at Buffalo. He
is a Faculty Scientist at Lawrence Berkeley National Laboratory,
NERSC Division and a co-director at the Berkeley Wireless
Research Center (BWRC). His research projects include
reconfigurable computing and computer architecture. He formed
the Berkeley Reconfigurable Computing group and pioneered
hardware architectures and programming models for hybrid systems
combining reconfigurable arrays with conventional processors
cores. He was principle investigator of the Research Accelerator for
Multiple Processors (RAMP) project that developed FPGAs-based
simulation systems for computer architecture research. He is
currently PI of the Berkeley ISIS project addressing the need for
rapid design space exploration and hardware/software co-design for
energy efficient many-core system development which is part of an
interdisciplinary team on the application of FPGA computing
technology to problems in systems biology. He currently teaches
courses in digital design, computer architecture, VLSI system
design, and reconfigurable computing. He was co-founder of Andes
Networks, a company specializing in the design and manufacturing
of accelerators for network security, and BEECube, Inc.,
specializing in reconfigurable computing systems.
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Paul K. Wright
Professor
A. Martin Berlin Chair in Mechanical Engineering
E-mail: pwright@bwrc.eecs.berkeley.edu
Research Web Page: http://www.me.berkeley.edu/faculty/wright/
Paul K. Wright is the Director for Center for Information
Technology in the Interest of Society (CITRIS) at UC Berkeley. It
serves four University of California campuses and hosts many
multi-disciplinary projects on large societal problems, including
healthcare, services and intelligent infrastructures such as energy,
water and sustainability. Professor Wright teaches in the
Mechanical Engineering department, where he holds the A. Martin
Berlin Chair. He also serves as co-director of the Berkeley
Manufacturing Institute (BMI) and co-director of the Berkeley
Wireless Research Center (BWRC). From 1995 to 2005 he served
as co-chair of the Management of Technology Program (a joint
program with the Haas School of Business). His research and
teaching are in high-tech product design and rapid manufacturing.
Currently, he and his colleagues are designing and prototyping
wireless systems for "Demand Response Power Management"
throughout California, funded by PIER/CEC (the Public Interest
Energy Research program of the California Energy Commission).
Born in London, England, he attended Birmingham and Cambridge
universities prior to attaining previous U.S. faculty positions at New
York University and Carnegie Mellon University.
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