Towards Socially Aware Person-Following Robots

Here is a new publication from our lab. This is a literature review that is focused on person-following in robotics from the perspective of the user. 1Published in IEEE THMS.



Significant R&D has been invested in technical issues related to person following. However, a systematic approach for designing robotic person-following behavior that maintains appropriate social conventions across contexts has not yet been developed. To understand why this may be the case, an in-depth literature review of 221 articles on person-following robots was performed, from which 107 are referenced. From these papers, six relevant topics were identified that shed light on the types of social interactions that have been studied in person-following scenarios: a) applications; b) robotic systems; c) environments; d) following strategies; e) human-robot communication; and f) evaluation methods. Gaps in the existing research on person-following robots were identified, mainly in addressing social interaction and user needs, noting that only 25 articles reported proper user studies. Human-related, robot-related, task-related, and environment-related factors that are likely to influence people’s spatial preferences and expectations of a robot’s person-following behavior are then discussed. To guide the design of socially aware person following robots, a user-needs layered design framework that combines the four factor categories is proposed. The framework provides a systematic way to incorporate social considerations in the design of person-following robots. Finally, framework limitations and future challenges in the field are presented and discussed.

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Old web pages that simply won’t disappear

I began working as a lecturer (academic tenure-track position) at BGU in 2006. When I arrived, there was a researcher website that new faculty were required to complete. I was relatively young at the time, and new to the system, but I remembered a tip given to me by my advisor and mentor, the distinguished P.A. Hancock. Long time before the “me too” campaign, Peter pointed out that in order to counter prejudice and bias of reviewers towards females, female researchers should avoid writing their full names on grant and article submissions and use initials instead (e.g., Jennifer is better off signing J.). Since my name is Tal (morning dew in Hebrew), and Tal is a common name for both genders in Israel, I could still use my name without hesitation.

Back to the story, the BGU website (Researcher profile) required filling the date of birth and place of birth. With Peter’s tip in mind and some notion of privacy, I decided not to fill my year of birth (I did not want anyone to think that I was too young :) or place. It so happened that since I did not fill this information, the default was filled instead. And so I found that in 2006, I was born in Uganda in 1921!!! Why Uganda? My guess is that it is because Uganda in Hebrew begins with an Aleph (the first alphabetical letter in Hebrew) so probably it was the first country on the list. Why 1921? probably the eldest faculty member in the BGU system at the time?!



My BGU Researcher Profile from 2006. Note my age and place of birth.


This research profile seemed to have a life of its own, at some point, it was not possible to edit the system anymore, it became outdated and was replaced by another Profiler. But somehow, it still seemed to draw some information from the BGU system: note that at some point my year of birth changed to 1926,  somewhere in 2013, when I was promoted to Associate professor, this information was updated as well, and in 2015 when I became the department Chair, that also was included in my academic position list. What did not change? everything else, my research interests, my research projects because I no longer had access to the system.

Not long after I arrived at BGU, researchers were asked to fill information on another researcher profile. I do not recall exactly when, but the picture tells that it was quite close to the time I arrived (2006). A close look at this profile, which I can no longer update either, shows again the confusion: I am a professor and a senior lecturer at the same time :), I am also the head of the department (since 2015), but nothing else seems right. And why would anyone care that 15 years ago, in 2003, I finished my PhD under the supervision of David Shinar? Is this really the most important information on a researcher’s website?



BGU’s current research profile system


Recently (2017), I was invited to give a lecture somewhere. My host introduced me as Prof. Oron-Gilad and then someone from the crowd said: why are you calling yourself a professor, you are only a senior lecturer, I saw it on your website.

Lastly,  to end the story with some optimism, by the end of 2017, BGU has launched a new research profiling system. So far it is current and can be updated by the researchers (Yeah!).  But, its hard to find the profiles because they were not indexed yet or linked to the BGU website. At least here everything is up to date, for now.


Take home message: Not everything you see is true.


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The effect of environmental distractions on child pedestrian’s crossing behavior

A new publication co-authored by Dr. Hagai Tapiro and Prof. Yisrael Parmet.

So often are we reminded about distraction from devices, cell phones or earphones. Yet, the environment we walk in can also have a detrimental effect on our road crossing safety. In this study we show that:

  • Distractions in the road environment put pedestrians at risk when crossing the road.
  • Pedestrian’s visual attention is affected by the façade of the street.
  • Younger children are at higher risk when distracted.
  • Visual distractions are more detrimental than auditory distractions.

Abstract: Pedestrians are subject to an increasing number of stimuli and distractions derived from the roadside environment. Although the effect of distractions on child road crossing ability was recognized, there has been no systematic exploration of the effects of roadside distractions on child road crossing behavior. This work was aimed at studying the effect of roadside distractions on pedestrian road crossing behavior, focusing on elementary school-aged children, who are less capable of making a safe road crossing decision and are more vulnerable to the effect of distractions. Three types of audio distractions (a. sudden, momentary, and prominent noise, b. multiplicity of auditory elements, and c. continuous loud noise) and similar three types of visual distractions were pre-defined. Fifty-two children (aged 7–13) and adults arrived at the dome virtual reality laboratory and viewed 20 simulated crossing scenarios, embedded with visual and auditory distractions, and decided on the appropriate time to start crossing the virtual road. The results demonstrate that when exposed to environmental distractions, participants chose smaller crossing gaps, took more time to make crossing decisions, were slower to respond to the crossing opportunity, and allocated less visual attention to the peripheral regions of the road. Those effects were age related, and affected younger participants more significantly. Furthermore, visual distractions affected pedestrian behavior more than auditory type distractions. This study highlights an issue not yet adequately addressed, and the results should be considered by transportation professionals, and road safety educators, so better road safety programs to educate children can be created.

Link to the manuscript: Anyone clicking on this link before May 19, 2018 will be taken directly to the final version of your article on ScienceDirect. No sign up, registration or fees are required – they can simply click and read.


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Pedestrians’ road crossing decisions and body parts’ movements is now available online

the final version of your article Pedestrians’ road crossing decisions and body parts’ movements is now available online, containing full bibliographic details.

See details in this post


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Pedestrians’ road crossing decisions and body parts’ movements

A new publication in TR part F by Semyon Kalantarov, Raziel Riemer, and Tal Oron-Gilad.


  • Road-crossing simulator synched with a 3D motion capturing system was built
  • Time pressure and longer wait times cause riskier crossing decisions
  • Pedestrians adjusted posture, crossing speed and timing of crossing to the risk taken
  • Body parts’ movement prior to the crossing can be divided into four increments

In this study we examined pedestrians’ crossing decision, body parts’ movement and full body movement, just before and during road crossing in a simulated setup. To accomplish this, a novel experimental setup for analyzing pedestrians’ crossing behavior and motion was developed where the simulated display was synchronized with a 3D motion capturing system. Twenty participants, divided into control and an experimental time pressure group, observed sixteen short (less than 30 seconds) and long road (70 seconds or more) crossing scenarios with varying crossing opportunities. Based on the crossing opportunities they were asked to cross a 3.6 m wide one-lane one way urban road. It was found that the crossing initiation process consists of four incremental movements of body parts: the head and the shoulder first; the hip, wrist and elbow second; the knee as a separate joint, and finally the ankle. Results showed that pedestrians’ decision to cross and body parts movement are influenced by time pressure and wait time for a safe crossing opportunity. Specifically, pedestrians prepare their body parts earlier, initiate their crossing earlier, and adjust their speed to compensate for the risk taken in less safe or non-safe crossing opportunities. Within the control group, women tended to be more risk avoiding than men, however those differences disappeared in the time pressure group. Most importantly, the findings provide initial evidence that this novel simulation configuration can be used to gain precise knowledge of pedestrians’ decision-making and movement processes.

What did we learn about pedestrians crossing movement?
Pedestrians change their strategy as a function of internal and external reasons:

  • Take higher risk when crossing opportunities are sparse or when they are under time pressure

Initiate crossing, Kalantarov, Riemer, and Oron-Gilad for TRF

  • Prepare their movement in advance by adjusting body position

body parts movement, Kalantarov, Riemer, and Oron-Gilad for TRF

  • Change the timing of crossing as a function of perceived risk

timing of crossing, Kalantarov, Riemer, and Oron-Gilad for TRF

  • Adjust their crossing speed to the perceived risk

walking speed, Kalantarov, Riemer, and Oron-Gilad for TRF

Kalantarov, S. , Riemer, R., Oron-Gilad, T. (in press). Pedestrians’ road crossing decisions and body parts’ movements. Transportation Research Part F: Psychology and Behaviour.

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