Announcement of a new NCCR Robotics associate PI: Laura Marchal Crespo

We are happy to announce that Prof. Laura Marchal-Crespo from ARTORG Center for Biomedical Engineering Research, University of Bern, has joined our NCCR Robotics community as associate PI in December 2017. Please join us welcoming Prof. Marchal-Crespo – her competences will be a great contribution to our research. – Dario Floreano (NCCR Director) and Robert Riener (NCCR Co-director) Laura Marchal-Crespo is an Assistant Professor at the …

Swiss Robotics Industry Day 2017 – extra seats added!

Thank you for your great interest in this year’s Swiss Robotics Industry Day organized in conjunction with digitalswitzerland and supported by the Canton of Vaud! We are happy to announce that some more seats are available at:  http://swissroboticsindustry.ch/register/ Please kindly note that applications for tickets are treated on a first-come, first-served basis and that the overall …

Harshal Sonar wins Best Poster Award at IROS 2017

During the IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS) which happened recently in Vancouver, Canada, Harshal Sonar, Doctoral Assistant for the Paik Lab, has won the Best Poster Award for his presentation on “Interactive SPA skin”. For more information, please visit the RRL website. For a short Youtube video on Interactive Soft Pneumatic Actuator Skin for Tactile …

Drones can almost see in the dark

(credit: UZH/Davide Scaramuzza) UZH researchers have taught drones how to fly using an eye-inspired camera, opening the door to them performing fast, agile maneuvers and flying in low-light environments. Possible applications could include supporting rescue teams with search missions at dusk or dawn. To fly safely, drones need to know their precise position and orientation …

New soft robots really suck!

Recent advances in soft robotics have seen the development of soft pneumatic actuators (SPAs) to ensure that all parts of the robot are soft, including the functional parts. These SPAs have traditionally used increased pressure in parts of the actuator to initiate movement, but today a team from NCCR Robotics and RRL, EPFL publish a …

Control of Motor-Imagery BCI by a User with Locked-In Syndrome

Using Brain Computer Interfaces (BCI) as a way to give people with locked-in syndrome back reliable communication and control capabilities has long been a futuristic trope of medical dramas and sci fi. A team from NCCR Robotics and CNBI, EPFL have recently published a paper detailing work as a step towards taking this technique into everyday lives …

Swiss Robotics Industry Day 2017 Announced

Taking place at the Swiss Tech Convention Centre, Lausanne, Switzerland, on 2nd November 2017, the Swiss Robotics Industry Day is an exclusive event for industry professionals to come and meet the labs of NCCR Robotics and the SMEs of the Swiss Robotics ecosystem. The event features talks from invited speakers from both industry and academia, with time for …

Multi-directional gravity assist helps rehabilitation training

When training to regain movement after stroke or spinal cord injury (SCI), patients must once again learn how to keep their balance during walking movements. Current clinical methods mean supporting the weight of the patient during movement, setting the body off balance and meaning that when patients are ready to begin to walk without mechanical …

Past Events

Date/Time Event Description
7 Jul – 13 Jul 2019
All Day
Summer School on Rehabilitation Robotics
Shangai Jiao Tong University, Shangai
The Summer School on Rehabilitation Robotics will take place at the Biomedical Engineering School, Shanghai Jiao Tong University (SJTU) between 7-13 July 2019. Organisers: - SJTU: Prof. Shanbao Tong, Prof....
1 Apr – 5 Apr 2019
All Day
Hannover Messe 2019
Deutsche Messe, Hannover
NCCR Robotics will be present at the Hannover Messe 2019 with a corporate booth and 3 additional booths for its spin-offs: Dronistics FES-ABILITY Sevensense The corporate booth will also showcase...
3 Dec – 4 Dec 2018
All Day
BMI Symposium 2018 "Controlling behavior"
EPFL, Lausanne Suisse
Prof. Pavan Ramdya, Prof. Carl Petersen & Prof. Auke Ijspeert (NCCR Robotics PI) invite you to the 2018 BMI Symposium on "Controlling behavior". With this one and a half day symposium, we...
23 Nov 2018
All Day
Neuroprosthetics Annual Research Symposium Prof. Stéphanie Lacour, NCCR Robotics PI and Director of the Center for Neuroprosthetics,  announces the First Neuroprosthetics Annual Research Symposium to be held on November 23rd, 2018, at Campus Biotech,...
1 Nov 2018
All Day
Swiss Robotics Industry Day 2018
SwissTech Convention Center, Ecublens
The next Swiss Robotics Industry Day will take place on November 1st, 2018 at the Swiss Tech Convention Centre, in Lausanne. All information on the event can be found here: http://swissroboticsindustry.ch
29 Oct – 31 Oct 2018
9:00 am – 5:00 pm
Conference on Robot Learning (CoRL 2018) CoRL 2018 will take place on October 29-31 2018 in Zurich. The conference focuses on the intersection of robotics and machine learning. CoRL aims at being a selective, top-tier venue...
18 Oct – 19 Oct 2018
All Day
SNSF Site Visit 2018 The 2018 SNSF Site Visit will take place in Bern, on October 18 and 19th. More information will be provided closer to the dates.
8 Oct – 9 Oct 2018
All Day
Aerial Futures: The Drone Frontier @ HUBweek
Boston District Hall, Boston
Swissnex Boston is gathering a selection of some of the most exciting drone exhibitors from Switzerland and the United States to bring to HUBweek. Expect an eclectic selection of UAVs...
31 Jul – 2 Aug 2018
All Day
EPFL Drone Days
EPFL, Lausanne Suisse
Some NCCR Robotics laboratories will present demos at the EPFL Drone Days 2018. https://dronedays.epfl.ch
2 Jul – 7 Jul 2018
All Day
ARCHE
Wangen an der Aare, Wangen an der Aare
The event took place in the training village of the civil protection forces of the Swiss Federal Department for Defense, Civil Protection and Sport and was used as field test...
1 Jun 2018
3:15 pm – 4:45 pm
Distinguished Seminar in Robotics, Systems & Control The Institute of Robotics and Intelligent Systems presents: Telerobotic Touch June 1st 2018, 15h15-16h15 Place: ETHZ, Main Building (HG G3) For those at EPFL: a video streaming will take place...
21 May – 25 May 2018
All Day
ICRA 2018, Brisbane, Australia
Brisbane Convention and Exhibition Center, South Brisbane
Roland Siegward, NCCR Robotics PI, will be a member of the Industry Forum Chairs Committee at ICRA 2018, in Brisbane, Australia. Margarita Chli, NCCR Robotics PI, will give a keynote...
23 Apr – 27 Apr 2018
All Day
Hannover Messe
Deutsche Messe, Hannover
NCCR Robotics has a booth within the Swiss Innovation Pavillion and will be accompanied by 2 two of our spin-offs:  MyoSwiss and Foldaway Haptics and the project "MIRobotics". For more information...
19 Apr 2018
All Day
Forward (Forum de l'Innovation pour les PME)
SwissTech Convention Center, Ecublens
NCCR Robotics will have a booth during this event, hosting two of our spin-offs Foldaway Haptics, and TWIICE.   https://forward-sme.epfl.ch  
13 Mar – 15 Mar 2018
All Day
European Robotics Forum
Tampere Hall, Tampere
The European Robotics Forum (ERF) 2018 hosted over 900 participants this year in Tampere, Finland from 13 to 15th March. NCCR Robotics was present with a booth, hosting two of...
12 Mar – 14 Mar 2018
All Day
AAAS Science Robotics Meeting
Plaza Heisei, Tokyo
Robert Riener, NCCR Robotics co-director, will give a keynote talk about Cybathlon at the AAAS Science Robotics Meeting in Tokyo, Japan.
8 Mar – 9 Mar 2018
All Day
NCCR Robotics Annual Retreat
Hotel Ambassador, Bern
The 2018 NCCR Robotics Annual Retreat (Bern, 8-9th March) was very successful, not only in bringing the community together but in achieving its targets in preparation for the next phase...
25 Jan 2018
1:30 pm – 3:30 pm
Motor learning and neurorehabilitation: training with or without errors? - A talk by Professor Laura Marchal Crespo Abstract: There is increasing interest in using robotic devices to provide rehabilitation therapy following stroke. Robotic guidance is generally used in motor training to reduce performance errors while practicing. However,...
12 Sep – 15 Sep 2017
All Day
11th Conference on Field and Service Robotics
ETH Zurich, Zurich
For more details and to register please see: https://www.fsr.ethz.ch/
1 Sep – 3 Sep 2017
All Day
EPFL Drone Days
EPFL, Lausanne Suisse
From 1 to 3 September 2017, EPFL's Ecublens campus will host the first-ever EPFL Drone Days. This event, which will include the Swiss drone racing championship, a robotics showcase and...
25 Jul 2017
6:30 pm
ROBOTIK-LABOR AN DER ETH ZÜRICH - TeleZüri Sendung Tune into TeleZüri at 18:30 to hear Robert Riener speaking about all things rehabilitation robotics and Cybathlon. http://www.telezueri.ch/64-show-sommertalk
5 Jul 2017
12:00 am
RSS 2017 Workshop: Challenges in Dynamic Legged Locomotion
Massachusetts Institute of Technology, Cambridge
The performance of modern legged robots still pales in comparison to their biological counterparts in terms of speed, robustness, versatility, and efficiency. The technical challenges that fuel this gap touch...
21 Jun 2017
2:00 pm – 3:00 pm
Talk by Prof. Harmut Geyer (CMU) on neuromechanical modeling of human locomotion
ME D1 1518, ecublens Suisse
Research at CMU’s Legged Systems Group Prof. Harmut Geyer, Carnegie Mellon University https://www.cs.cmu.edu/~hgeyer/ Abstract: Research at CMU’s legged systems group focuses on three questions: What are the principles of legged...
15 Jun – 16 Jun 2017
All Day
Building Bodies for Brains & Brains for Bodies & 3rd Japan-EU Workshop on Neurorobotics
Geneva, Geneva
Building Bodies for Brains & Brains for Bodies & 3rd Japan-EU Workshop on Neurorobotics Registration for both events now open.
5 Jun – 10 Jun 2017
All Day
Summer School on Rehabilitation Robotics
Biomedical Engineering School, Shanghai
Organised by the Riener Lab, ETH Zurich. For more information please see: http://www.sms.hest.ethz.ch/news-and-events/sms-news-channel/2017/01/summer-school-on-rehabilitation-robotics.html          
2 Jun 2017
8:30 am – 5:00 pm
ICRA Workshop on Event-based vision
sands expo and convention centre, Singapore 018971
Tobi Delbruck and Davide Scaramuzza are confirmed speakers. For more information please see: http://rpg.ifi.uzh.ch/ICRA17_event_vision_workshop.html  
16 May – 18 May 2017
All Day
InnoRobo
Paris, Paris
Read more
24 Apr – 28 Apr 2017
All Day
Hannover Messe
Hannover Messe, Hannover
We will present a booth at the Hannover Messe along with Swiss Robotics partners. To organise a meeting with us please contact techtransfer@nccr-robotics.ch 
5 Apr 2017
11:00 am – 12:00 pm
Talk: Hearing the light: Optogenetic Sti
Campus Biotech, H8 Auditorium, Geneva
Hearing the light: Optogenetic Sti by Tobias Moser Institute for Auditory Neuroscience & InnerEarLab, University Medical Center Goettingen, GE. For more information please see the seminar website.
28 Mar 2017
2:30 pm – 4:30 pm
Talks: By Professor Fumiya Iida & By Professor Robert J. Full
EPFL, Lausanne Suisse
Talks: Model-free design optimization of soft robots: Any hope? By Professor Fumiya Iida (Cambridge Univ.), (14:30 – 15:30). BioMotion Science: Leapin’ Lizards, Compressed Cockroaches and Smart Squirrels Inspire Robots By...
20 Mar 2017
6:15 pm – 7:45 pm
Talk: Roboter als Reha-Helfer im Einsatz by Robert Riener
Universität Zurich Zentrum, Hörsaal KOL-F-101, Zurich
For more information please see the official flyer.
16 Mar 2017
10:00 am – 11:00 am
Talk by Prof. Eric Tytell (Tufts University), Quantifying responses to perturbations during locomotion in fish
MED 115 18, EPFL, Lausanne
6 Mar – 9 Mar 2017
All Day
R4L @HRI2017
Aula der Wissenschaft – Hall of Science, Vienna
http://r4l.epfl.ch/HRI2017
2 Mar 2017
12:30 pm – 2:00 pm
Business Ideas @EPFL Swiss Robotics going global
SwissTech Convention Center, Ecublens
www.ifj.ch/cti-epfl
2 Mar 2017
12:30 pm – 2:00 pm
Business Ideas @EPFL
SwissTech Convention Center, Ecublens
http://www.ifj.ch/cti-epfl
13 Feb 2017
2:00 pm – 3:00 pm
Talk by Dr Diego Pardo (ETHZ) Legged Robots: Stepping out of the continuous and differentiable zone.
EPFL, Lausanne
16 Dec 2016
3:15 pm – 4:15 pm
Talk: MIT Cheetah: new design paradigm shift toward mobile robots, ETH Distinguished Lecture in Robotics, Systems & Control - Sangbae Kim
ETH Zurich, HG G3, Zurich
9 Nov 2016
10:00 am – 11:00 am
Talk: Rehabilitation robotics - Cristina Santos, Universidade do Minho, Portugal; Dealing with uncertainty in robot grasping - Alexandre Bernardino, Instituto Superior Técnico, Lisbon, Portugal; Locomotion with the Walkman humanoid robot - Nikos Tsagarakis, Istituto Italiano di Tecnologia, Genova, Italy.
MED 115 18, EPFL, Lausanne
4 Nov 2016
3:15 pm – 4:15 pm
Talk: Designing and Controlling Robots for Direct Interaction with Humans by Prof. Alin Albu-Schaeffer, German Aerospace Center, Germany.
ETH Zurich, HG G3, Zurich
2 Nov 2016
All Day
Swiss Robotics Industry Day
SwissTech Convention Center, Ecublens
Please see www.swissindustryday.ch
23 Oct – 27 Oct 2016
All Day
International Symposium on Safety, Security and Rescue Robotics (SSRR 16)
EPFL, Lausanne Suisse
Please see http://ssrrobotics.org/index.html
9 Oct – 12 Oct 2016
All Day
WORKSHOP ON BRAIN-MACHINE INTERFACES (SMC 2016)
Intercontinental Hotel, BUDAPEST, 1052 Budapest
Please see: https://documents.epfl.ch/users/c/ch/chavarri/www/IEEESMC2016_BMI/BMI-IEEESMC2016.html
8 Oct 2016
12:00 am
Cybathlon 2016
SWISS Arena, Kloten
Please see www.cybathlon.com
6 Oct 2016
All Day
Cybathlon Symposium
SWISS Arena, Kloten
For further information, please see http://www.cybathlon-symposium.ethz.ch/
30 Sep – 7 Jan 2016
All Day
The origami robot Tribot from Paik lab is currently at the exhibition in +Ultra Knowledge & Gestaltung in Berlin
23 Sep 2016
3:15 pm – 4:15 pm
Talk: Humanitarian Robotics and Automation Technologies by Dr. Raj Madhavan
ETH Zurich, HG G3, Zurich
13 Jul – 15 Jul 2016
All Day
Workshop on Dynamic Locomotion and Manipulation (DLMC2016)
ETH Zurich, Zurich
Please see the website http://www.dlmc2016.ethz.ch/

Looking for publications? You might want to consider searching on the EPFL Infoscience site which provides advanced publication search capabilities.

Cellulo: Versatile Handheld Robots for Education

  • Authors: Ozgur, Ayberk; Lemaignan, Séverin; Johal, Wafa; Beltran, Maria; Briod, Manon; Pereyre, Léa; Mondada, Francesco; Dillenbourg, Pierre

In this article, we present Cellulo, a novel robotic platform that investigates the intersection of three ideas for robotics in education: designing the robots to be versatile and generic tools; blending robots into the classroom by designing them to be pervasive objects and by creating tight interactions with (already pervasive) paper; and finally considering the practical constraints of real classrooms at every stage of the design. Our platform results from these considerations and builds on a unique combination of technologies: groups of handheld haptic-enabled robots, tablets and activity sheets printed on regular paper. The robots feature holonomic motion, haptic feedback capability and high accuracy localization through a microdot pattern overlaid on top of the activity sheets, while remaining affordable (robots cost about EUR 125 at the prototype stage) and classroom-friendly. We present the platform and report on our first interaction studies, involving about 230 children.

Posted on: January 9, 2017

Classification of upper limb center-out reaching tasks by means of EEG-based continuous decoding techniques

  • Authors: Ubeda, Andrés; Azorín, José M.; Chavarriaga, Ricardo; Millán, José del R.

Background: One of the current challenges in brain-machine interfacing is to characterize and decode upper limb kinematics from brain signals, e.g. to control a prosthetic device. Recent research work states that it is possible to do so based on low frequency EEG components. However, the validity of these results is still a matter of discussion. In this paper, we assess the feasibility of decoding upper limb kinematics from EEG signals in center-out reaching tasks during passive and active movements. Methods: The decoding of arm movement was performed using a multidimensional linear regression. Passive movements were analyzed using the same methodology to study the influence of proprioceptive sensory feedback in the decoding. Finally, we evaluated the possible advantages of classifying reaching targets, instead of continuous trajectories. Results: The results showed that arm movement decoding was significantly above chance levels. The results also indicated that EEG slow cortical potentials carry significant information to decode active center-out movements. The classification of reached targets allowed obtaining the same conclusions with a very high accuracy. Additionally, the low decoding performance obtained from passive movements suggests that discriminant modulations of low-frequency neural activity are mainly related to the execution of movement while proprioceptive feedback is not sufficient to decode upper limb kinematics. Conclusions: This paper contributes to the assessment of feasibility of using linear regression methods to decode upper limb kinematics from EEG signals. From our findings, it can be concluded that low frequency bands concentrate most of the information extracted from upper limb kinematics decoding and that decoding performance of active movements is above chance levels and mainly related to the activation of cortical motor areas. We also show that the classification of reached targets from decoding approaches may be a more suitable real-time methodology than a direct decoding of hand position.

Posted on: January 27, 2017

Climbing favours the tripod gait over alternative faster insect gaits

  • Authors: Ramdya, Pavan; Thandiackal, Robin; Cherney, Raphael; Asselborn, Thibault; Benton, Richard; Ijspeert, Auke; Floreano, Dario

To escape danger or catch prey, running vertebrates rely on dynamic gaits with minimal ground contact. By contrast, most insects use a tripod gait that maintains at least three legs on the ground at any given time. One prevailing hypothesis for this difference in fast locomotor strategies is that tripod locomotion allows insects to rapidly navigate three-dimensional terrain. To test this, we computationally discovered fast locomotor gaits for a model based on Drosophila melanogaster. Indeed, the tripod gait emerges to the exclusion of many other possible gaits when optimizing fast upward climbing with leg adhesion. By contrast, novel two-legged bipod gaits are fastest on flat terrain without adhesion in the model and in a hexapod robot. Intriguingly, when adhesive leg structures in real Drosophila are covered, animals exhibit atypical bipod-like leg coordination. We propose that the requirement to climb vertical terrain may drive the prevalence of the tripod gait over faster alternative gaits with minimal ground contact.

Posted on: February 18, 2017

Concurrent Optimization of Mechanical Design and Locomotion Control of a Legged Robot

  • Authors: Digumarti, K. M.; Gehring, C.; Coros, S.; Hwangbo, J.; Siegwart, R.

This paper introduces a method to simultaneously optimize design and control parameters for legged robots to improve the performance of locomotion based tasks. The morphology of a quadrupedal robot was optimized for a trotting and bounding gait to achieve a certain speed while tuning the control parameters of a robust locomotion controller at the same time. The results of the optimization show that a change of the structure of the robot can help increase its admissable top speed while using the same actuation units.

Posted on: July 16, 2014

Contact-based navigation for an autonomous flying robot

  • Authors: Briod, Adrien; Kornatowski, Przemyslaw Mariusz; Klaptocz, Adam; Garnier, Arnaud; Pagnamenta, Marco; Zufferey, Jean-Christophe; Floreano, Dario

Autonomous navigation in obstacle-dense indoor environments is very challenging for flying robots due to the high risk of collisions, which may lead to mechanical damage of the platform and eventual failure of the mission. While conventional approaches in autonomous navigation favor obstacle avoidance strategies, recent work showed that collision-robust flying robots could hit obstacles without breaking and even self-recover after a crash to the ground. This approach is particularly interesting for autonomous navigation in complex environments where collisions are unavoidable, or for reducing the sensing and control complexity involved in obstacle avoidance. This paper aims at showing that collision-robust platforms can go a step further and exploit contacts with the environment to achieve useful navigation tasks based on the sense of touch. This approach is typically useful when weight restrictions prevent the use of heavier sensors, or as a low-level detection mechanism supplementing other sensing modalities. In this paper, a solution based on force and inertial sensors used to detect obstacles all around the robot is presented. Eight miniature force sensors, weighting 0.9g each, are integrated in the structure of a collision-robust flying platform without affecting its robustness. A proof-of-concept experiment demonstrates the use of contact sensing for exploring autonomously a room in 3D, showing significant advantages compared to a previous strategy. To our knowledge this is the first fully autonomous flying robot using touch sensors as only exteroceptive sensors.

Posted on: July 1, 2013

Contactless deflection sensing of concave and convex shapes assisted by soft mirrors

  • Authors: Dobrzynski, Michal; Halasz, Ionut; Pericet Camara, Ramon; Floreano, Dario

Typical deflection sensors like strain gauges or devices based on optical fibers require physical contact with the deflected substrate during the measurement process. Such contact, however, impacts on the softness of the substrate and may falsify the measurements. In order to overcome this drawback, a novel method of contactless deflection sensing was proposed in a recent work. It was verified that the deflection angle between two planes can be extracted using only a photosensor and a light source bearing a bell-shape angular emission profile. Yet, the range of operation was limited to concave shapes. In this paper, we introduce an alternative configuration of this light-based deflection sensing method to extend its functionality to convex surfaces. Here, a spheroidal mirror bearing a customized profile is introduced above the light source. This mirror redirects part of the emitted light towards the photosensor hindered by the bending surface during convex deflections.We make use of a ray tracing simulation method to design the mirror profiles, which are accurately reproduced in the manufactured prototypes by tuning the fabrication variables of the manufacturing process. Using a shape-sensing prototype, it is verified that the use of the mirror extends the range of detectable deflections by 55deg. to convex bendings, yielding a deviation of only 8.3% from simulated results. Our deflection sensing solution is a promising method to be used as a shape sensor in numerous applications, such as soft robotics platforms or prosthetic devices.

Posted on: March 13, 2012

Contactless deflection sensor for soft robots

  • Authors: Dobrzynski, Michal; Pericet Camara, Ramon; Floreano, Dario

In the emerging field of soft robotics, there is an interest in developing new kinds of sensors whose characteristics do not affect the intrinsic compliance of soft robot components. Additionally, non-invasive shape and deflection sensors may provoke improved solutions to assist in the control of mechanical parts in these robots. Herein, we introduce a novel method for deflection sensing where an LED element and a photodiode are placed on to two substrates connected physically or virtually at a deflection point. The deflection angle between the two planes can be extracted from the LED light intensity detected at the photodiode due to the bell-shaped angular intensity profile of the emitted light. The main advantage of this system is that the components are not in physical contact with the deflection region as in the case of strain gauges and similar sensing methods. The sensor is characterized in a range of deflections of 105-180 degrees, showing a near 1 degree resolution. The experimental data are compared to simulations, modeled by ray tracing. The light intensity vs. deflection angle measurements in our setup display a maximum difference of 9% and an average difference of approximately 5% with respect to the model. Finally, a shape monitoring system has been developed using the proposed concept for a flexible PCB. The system is composed of 12 deflection sensors that operate at frame rate of 33 Hz. This device could be applied to monitor the body shape of a soft robot.

Posted on: July 15, 2011

Cutting Down the Energy Consumed by Domestic Robots: Insights from Robotic Vacuum Cleaners

  • Authors: Vaussard, Florian Christopher; Rétornaz, Philippe; Hamel, David; Mondada, Francesco

The market of domestic service robots, and especially vacuum cleaners, has kept growing during the past decade. According to the International Federation of Robotics, more than 1 million units were sold worldwide in 2010. Currently, there is no in-depth analysis of the energetic impact of the introduction of this technology on the mass market. This topic is of prime importance in our energy-dependant society. This study aims at identifying key technologies leading to the reduction of the energy consumption of a domestic mobile robot, by exploring the design space using technologies issued from the robotic research field, such as the various localization and navigation strategies. This approach is validated through an in-depth analysis of seven vacuum cleaning robots. These results are used to build a global assessment of the influential parameters. The major outcome is the assessment of the positive impact of both the ceiling-based visual localization and the laser-based localization approaches.

Posted on: May 31, 2012