Julien Gori

Julien Gori

HCI Researcher

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This is a list of my publications. Clink on each associated link to access a short informal summary. You can also look for my Google scholar profile in the menu on the left.

A list of all the posts and pages found on the site. For you robots out there is an XML version available for digesting as well.

Pages

To Miss is Human: Information-Theoretic Rationale for Target Misses in Fitts’ Law (ACM CHI, 2017)

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This work discusses how to treat target misses in a Fitts’ law task, and in particular the distinction between errors, where the amplitude of the miss matters, and erasures, where the amplitude of the miss does not matter. This idea is also exploited in our 2018 TOCHI submission

Recommended citation: Gori, Julien, Olivier Rioul, and Yves Guiard. "To Miss is Human: Information-Theoretic Rationale for Target Misses in Fitts’ Law." Proceedings of the 2017 CHI Conference on Human Factors in Computing Systems. 2017. https://hal.archives-ouvertes.fr/hal-01690133/document

One fitts’ law, two metrics (IFIP INTERACT, 2017)

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Fitts’ law is used in HCI to measure the average, best performances. Here we argue that it would be more clear to use two distinct metrics, one for the average performance, the other for the best performance. This is particularly useful when comparing data from a controlled study to more ecologically valid data.

Recommended citation: Gori, Julien, et al. "One Fitts law, two metrics." IFIP Conference on Human-Computer Interaction. Springer, Cham, 2017. https://hal.inria.fr/hal-01717202/document

Information-theoretic analysis of the speed-accuracy tradeoff with feedback (IEEE SMC, 2018)

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In our 2018 TOCHI publication, we presented a full transmission model from which Fitts’ law could be derived. However, that model was not capable of encompassing feedback. Here, we propose to adapt a transmission scheme with feedback to the case of pointing.

Recommended citation: Gori, Julien, and Olivier Rioul. "Information-theoretic analysis of the speed-accuracy tradeoff with feedback." 2018 IEEE International Conference on Systems, Man, and Cybernetics (SMC). IEEE, 2018. https://hal.archives-ouvertes.fr/hal-02111178/document

The perils of confounding factors: How Fitts’ law experiments can lead to false conclusions (ACM CHI, 2018)

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In this paper, we study how and why the typical experiment design in Fitts’ law studies does not allow one to discriminate between the Fitts model and a simple distance covering model. We propose a simple check to make sure you are not exposed to that risk when conducting a Fitts’ law study.

Recommended citation: Gori, Julien, et al. "The perils of confounding factors: How Fitts’ law experiments can lead to false conclusions." Proceedings of the 2018 CHI Conference on Human Factors in Computing Systems. 2018. https://hal.archives-ouvertes.fr/hal-01690089/document

Speed-accuracy tradeoff: A Formal Information-Theoretic Transmission Scheme (FITTS) (ACM TOCHI, 2018)

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The information-theoretic basis of Fitts’ law is usually understood in HCI via Fitts’ original analogy and Mackenzie’s work from the nineties. Here, we go beyond the analogy and propose a complete transmission scheme. We start by proposing a unifying approach under which to analyze several existing variations of the Index of Difficulty. We then provide a better correspondence between Shannon’s information theory and Fitts’ law, expressing the law as the result of a channel capacity calculation. A uniform noise model is considered, which is then gradually relaxed to encompass a quasi Gaussian noise case.

Recommended citation: Gori, Julien, Olivier Rioul, and Yves Guiard. "Speed-accuracy tradeoff: A Formal Information-Theoretic Transmission Scheme (FITTS)." ACM Transactions on Computer-Human Interaction (TOCHI) 25.5 (2018): 1-33. https://hal.archives-ouvertes.fr/hal-01690122/file/main.pdf

Multi-evaluation of pointing and application to dyspraxia evaluation (AFIHM IHM, 2019)

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In this work, we compare several methods to evaluate pointing for atypical populations. We used data from dyspraxic children which were compared to typical adults. We namely compare the methods described in our 2019 EUSIPCO and 2020 Biological Cybernetics paper.

Recommended citation: Gori, Julien, Michel Beaudouin-Lafon, and Yves Guiard. "Multi-evaluation of pointing and application to dyspraxia evaluation." Proceedings of the 31st Conference on l’Interaction Homme-Machine. 2019. https://dl.acm.org/doi/pdf/10.1145/3366550.3372250

Regression to a linear lower bound with outliers: An exponentially modified Gaussian noise model (EURASIP EUSIPCO, 2019)

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In our 2018 TOCHI and 2017 Interact paper we had proposed to fit Fitts’ law on the best performing points of a scatter plot in the (MT,ID) plane. However, there is no existing method for this type of fit. In this work, we explain a method that precisely achieves this type of fitting i.e. esimating a linear lower bound of a scatter plot, when some points may cheat below that lower bound.

Recommended citation: Gori, Julien, and Olivier Rioul. "Regression to a linear lower bound with outliers: An exponentially modified Gaussian noise model." 2019 27th European Signal Processing Conference (EUSIPCO). IEEE, 2019. https://hal.archives-ouvertes.fr/hal-02191051/document

A Feedback Information-Theoretic Transmission Scheme (FITTS) for modeling trajectory variability in aimed movements (Biological Cybernetics, 2020)

Published:

Our information theoretic model with feedback presented at SMC 2018 is extended. We tackle the description of complete trajectories and incorporate a feedback mechanism. We find a characterization on the speed at which variability is reduced throughout the movement. This decrease explains Fitts’ law, and more generally, the speed-accuracy tradeoff.

Recommended citation: Gori, Julien, and Olivier Rioul. "A Feedback Information-Theoretic Transmission Scheme (FITTS) for modeling trajectory variability in aimed movements." Biological Cybernetics 114.6 (2020): 621-641. https://hal.archives-ouvertes.fr/hal-03060086/document

FileWeaver: Flexible File Management with Automatic Dependency Tracking (ACM UIST, 2020)

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When we work on complex documents, we maintain an internal representation of the dependencies between various files needed to produce the final output, as well as their various histories. In this project, we make this internal representation explicit, and interactive. This provides the user with many additional features, including automation.

Recommended citation: Gori, Julien, Han L. Han, and Michel Beaudouin-Lafon. "FileWeaver: Flexible File Management with Automatic Dependency Tracking." Proceedings of the 33rd Annual ACM Symposium on User Interface Software and Technology. 2020. https://hal.archives-ouvertes.fr/hal-02981632/document

Not Just Pointing: Shannon’s Information Theory as a General Tool for Performance Evaluation of Input Techniques (Technical Report, 2017)

Published:

Shannon’s Information Theory is usually regarded in HCI as an old theory that has only been useful in the context of Fitts’ law. Yet, information theory is a statistical description of symbols, and therefore can potentially map to many other scenarios in HCI. Here, we attempted to show some potential benefits of using Shannon’s information theory. This is still work in progress; in fact it has been on hold for some time now. If you feel like this is interesting and you would be willing to contribute/have some ideas about this, contact me.

Recommended citation: Guiard, Yves, et al. "Not Just Pointing: Shannon’s Information Theory as a General Tool for Performance Evaluation of Input Techniques." (2017). https://hal.archives-ouvertes.fr/hal-02090158/document

How Relevant is Hick’s Law for HCI? (ACM CHI, 2020)

Published:

Hick’s Law is used in HCI to justify some design choices, namely to decrease the number of items displayed at once. Here, we revisit this traditional design choice, and show that Hick’s law would advocate the opposite. We then argue that Hick’s law has little to offer to HCI. We then provide a design principle regarding the number of items to display at once based on the convexity of the response time function.

Recommended citation: Liu, Wanyu, et al. "How Relevant is Hick’s Law for HCI?." Proceedings of the 2020 CHI Conference on Human Factors in Computing Systems. 2020. https://hal.archives-ouvertes.fr/hal-02867301/file/HickLaw-CHI20-HAL.pdf

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Posts

Future Blog Post (, 2199)

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Blog Post number 4 (, 2015)

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Blog Post number 3 (, 2014)

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This is a sample blog post. Lorem ipsum I can’t remember the rest of lorem ipsum and don’t have an internet connection right now. Testing testing testing this blog post. Blog posts are cool.

Blog Post number 2 (, 2013)

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This is a sample blog post. Lorem ipsum I can’t remember the rest of lorem ipsum and don’t have an internet connection right now. Testing testing testing this blog post. Blog posts are cool.

Blog Post number 1 (, 2012)

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This is a sample blog post. Lorem ipsum I can’t remember the rest of lorem ipsum and don’t have an internet connection right now. Testing testing testing this blog post. Blog posts are cool.

portfolio

publications

talks

Talk 1 on Relevant Topic in Your Field (UC San Francisco, Department of Testing, 2012)

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teaching

Teaching experience 1 (University 1, Department, 2014)

Undergraduate course, University 1, Department, 2014

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Teaching experience 2 (University 1, Department, 2015)

Workshop, University 1, Department, 2015

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