Remco Veltkamp

Prof. Remco Veltkamp

Utrecht University
orcid

Research Focus & Metrics

Academic Career Length

22Years (2005-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 March 2019 in Signal Processing: Image Communication
Verified
Journal Article
Closed access
ZTZhigang Tu
Zhigang Tu
WXWei Xie
Wei Xie
DZDejun Zhang
Dejun Zhang
RPRonald Poppe
Ronald Poppe
Remco VeltkampRemco Veltkamp
Remco Veltkamp
JYJunsong Yuan
Junsong Yuan

Verified
Journal Article
Open access
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MCMarten L. Chaillet
Marten L. Chaillet
GSGijs van der Schot
Gijs van der Schot
IGIlja Gubins
Ilja Gubins
SRSander Roet
Sander Roet
Remco VeltkampRemco Veltkamp
Remco Veltkamp
FFFriedrich Foerster
Friedrich Foerster
Cryo-electron tomography provides 3D images of macromolecules in their cellular context. To detect macromolecules in tomograms, template matching (TM) is often used, which uses 3D models that are often reliable for substantial parts of the macromolecules. However, the extent of rotational searches in particle detection has not been investigated due to computational limitations. Here, we provide a GPU implementation of TM as part of the PyTOM software package, which drastically speeds up the orientational search and allows for sampling beyond the Crowther criterion within a feasible timeframe. We quantify the improvements in sensitivity and false-discovery rate for the examples of ribosome identification and detection. Sampling at the Crowther criterion, which was effectively impossible with CPU implementations due to the extensive computation times, allows for automated extraction with high sensitivity. Consequently, we also show that an extensive angular sample renders 3D TM sensitive to the local alignment of tilt series and damage induced by focused ion beam milling. With this new release of PyTOM, we focused on integration with other software packages that support more refined subtomogram-averaging workflows. The automated classification of ribosomes by TM with appropriate angular sampling on locally corrected tomograms has a sufficiently low false-discovery rate, allowing for it to be directly used for high-resolution averaging and adequate sensitivity to reveal polysome organization.

12 October 2017 in JMIR Serious Games
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Journal Article
Open access
YLYun Ling
Yun Ling
LMLouis P Ter Meer
Louis P Ter Meer
ZYZerrin Yumak
Zerrin Yumak
Remco VeltkampRemco Veltkamp
Remco Veltkamp
Patients who receive rehabilitation after hip replacement surgery are shown to have increased muscle strength and better functional performance. However, traditional physiotherapy is often tedious and leads to poor adherence. Exercise games, provide ways for increasing the engagement of elderly patients and increase the uptake of rehabilitation exercises. The objective of this study was to evaluate Fietsgame (Dutch for cycling game), which translates existing rehabilitation exercises into fun exercise games. The system connects exercise games with a patient's personal record and a therapist interface by an Internet of Things server. Thus, both the patient and physiotherapist can monitor the patient's medical status. This paper describes a pilot study that evaluates the usability of the Fietsgame. The study was conducted in a rehabilitation center with 9 participants, including 2 physiotherapists and 7 patients. The patients were asked to play 6 exercise games, each lasting about 5 min, under the guidance of a physiotherapist. The mean age of the patients was 74.57 years (standard deviation [SD] 8.28); all the patients were in the recovery process after hip surgery. Surveys were developed to quantitatively measure the usability factors, including presence, enjoyment, pain, exertion, and technology acceptance. Comments on advantages and suggested improvements of our game system provided by the physiotherapists and patients were summarized and their implications were discussed. The results showed that after successfully playing the games, 75% to 100% of the patients experienced high levels of enjoyment in all the games except the squats game. Patients reported the highest level of exertion in squats when compared with other exercise games. Lunges resulted in the highest dropout rate (43%) due to interference with the Kinect v2 from support chairs. All the patients (100%) found the game system useful and easy to use, felt that it would be a useful tool in their further rehabilitation, and expressed that they would like to use the game in the future. The therapists indicated that the exercise games highly meet the criteria of motor rehabilitation, and they intend to continue using the game as part of their rehabilitation treatment of patients. Comments from the patients and physiotherapists suggest that real-time corrective feedback when patients perform the exercises wrongly and a more personalized user interface with options for increasing or decreasing cognitive load are needed. The results suggest that Fietsgame can be used as an alternative tool to traditional motor rehabilitation for patients with hip surgery. Lunges and squats are found to be more beneficial for patients who have relatively better balance skills. A follow-up randomized controlled study will be conducted to test the effectiveness of the Fietsgame to investigate how motivating it is over a longer period of time.

14 October 2024 in Proceedings of the ACM on Human-Computer Interaction
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Journal Article
Open access
MWMichel Wijkstra
Michel Wijkstra
KRKatja Rogers
Katja Rogers
RMRegan L. Mandryk
Regan L. Mandryk
Remco VeltkampRemco Veltkamp
Remco Veltkamp
JFJulian Frommel
Julian Frommel
Toxic behavior is known to cause harm in online games. Players regularly experience negative, hateful, or inappropriate behavior. Interventions, such as banning players or chat message filtering, can help combat toxicity but are not widely available or even comprehensively studied regarding their approaches and evaluations. We conducted a systematic literature review that provides insights into the current state of interventions literature, outlining their strengths and shortcomings. We identified 36 interventions and qualitatively analyzed their approaches. We describe the types of toxicity being addressed, the entities through which they act, the methods used by intervention systems, and how they are evaluated. Our results provide guidance for future interventions, outlining a design space based on known systems. Furthermore, our findings highlight gaps in the literature, e.g., a sparsity of empirical evaluations, and underexplored areas in the design space, enabling researchers to explore novel directions for future interventions.


23 February 2021 in IEEE Transactions on Pattern Analysis and Machine Intelligence
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Journal Article
Open access
GKGeorgios Kapidis
Georgios Kapidis
Ronald PoppeRonald Poppe
Ronald Poppe
Remco VeltkampRemco Veltkamp
Remco Veltkamp
For egocentric vision tasks such as action recognition, there is a relative scarcity of labeled data. This increases the risk of overfitting during training. In this paper, we address this issue by introducing a multitask learning scheme that employs related tasks as well as related datasets in the training process. Related tasks are indicative of the performed action, such as the presence of objects and the position of the hands. By including related tasks as additional outputs to be optimized, action recognition performance typically increases because the network focuses on relevant aspects in the video. Still, the training data is limited to a single dataset because the set of action labels usually differs across datasets. To mitigate this issue, we extend the multitask paradigm to include datasets with different label sets. During training, we effectively mix batches with samples from multiple datasets. Our experiments on egocentric action recognition in the EPIC-Kitchens, EGTEA Gaze+, ADL and Charades-EGO datasets demonstrate the improvements of our approach over single-dataset baselines. On EGTEA we surpass the current state-of-the-art by 2.47 percent. We further illustrate the cross-dataset task correlations that emerge automatically with our novel training scheme.