VLDB 2026 Research / reviewers in the wild / expert
Umar Mohammed
dblp:72/5161
· DBLP profile ↗
5ranked-venue papers
1as first author
1since 2021 · last 2026
—ORCID · none
Domains — the database's venue-derived domains; a paper can count in several
Artificial intelligence and machine learning · 4 · 1 since 2021Graphics, computer vision, multimedia, augmented reality and games · 4 · 1 first-author · 1 since 2021
Expertise — from the expertise taxonomy: the topics of the expert's papers under the CCF categories. A weight counts papers with recency: 1 for a paper about the topic, 0.3 when the topic is its context, halved every five years.
| Artificial intelligence
4 papers |
Multi-agent systems · 36% Trustworthy machine learning · 36% Generative modeling · 12% | |
| Databases, data mining, and information retrieval
1 paper |
Knowledge graphs · 100% | |
| Computer graphics and multimedia
2 papers |
Image and video processing · 100% |
Topics — the 15 heaviest of 15, each with the papers that count most for it
| Topic | Weight | Papers | Last | Evidence papers |
|---|---|---|---|---|
Knowledge, reasoning and agents › Multi-agent systems
agentic AI |
1.0 | 1 | 2026 | AgentGraph: Trace-to-Graph Platform for Interactive Analysis and Robustness Testing in Agentic AI Systems · AAAI 2026 |
Machine learning › Trustworthy machine learning
robustness evaluation |
1.0 | 1 | 2026 | AgentGraph: Trace-to-Graph Platform for Interactive Analysis and Robustness Testing in Agentic AI Systems · AAAI 2026 |
Knowledge graphs
knowledge graph construction |
0.3 | 1 | 2026 | AgentGraph: Trace-to-Graph Platform for Interactive Analysis and Robustness Testing in Agentic AI Systems · AAAI 2026 |
Computer vision › Face, body and person analysis
face recognition |
0.1 | 1 | 2012 | Probabilistic Models for Inference about Identity · IEEE Trans. Pattern Anal. Mach. Intell. 2012 |
Computer vision › Face, body and person analysis
face manipulation |
0.1 | 1 | 2009 | Visio-lization: generating novel facial images · ACM Trans. Graph. 2009 |
Machine learning › Generative modeling
face synthesis |
0.1 | 1 | 2009 | Visio-lization: generating novel facial images · ACM Trans. Graph. 2009 |
Machine learning › Generative modeling › diffusion model
image editing |
0.1 | 1 | 2009 | Visio-lization: generating novel facial images · ACM Trans. Graph. 2009 |
Machine learning › Generative modeling
image generation |
0.1 | 1 | 2009 | Visio-lization: generating novel facial images · ACM Trans. Graph. 2009 |
Computer vision › Segmentation and scene understanding › image segmentation
segmentation evaluation |
0.1 | 1 | 2009 | Scene shape priors for superpixel segmentation · ICCV 2009 |
Computer vision › Segmentation and scene understanding › image segmentation › region-based segmentation
superpixel segmentation |
0.1 | 1 | 2009 | Scene shape priors for superpixel segmentation · ICCV 2009 |
Image and video processing
image segmentation |
0.1 | 1 | 2008 | Superpixel lattices · CVPR 2008 |
Image and video processing › image segmentation › superpixel segmentation
superpixel lattice |
0.1 | 1 | 2008 | Superpixel lattices · CVPR 2008 |
Image and video processing › image segmentation
superpixel segmentation |
0.1 | 1 | 2008 | Superpixel lattices · CVPR 2008 |
Machine learning › Generative modeling › face synthesis
generative face model |
0.0 | 1 | 2012 | Probabilistic Models for Inference about Identity · IEEE Trans. Pattern Anal. Mach. Intell. 2012 |
Image and video processing › image restoration
image inpainting |
0.0 | 1 | 2009 | Visio-lization: generating novel facial images · ACM Trans. Graph. 2009 |
Methods — techniques the papers use, named apart from their topics
trace-grounded failure detection · 2.0interactive knowledge graph · 2.0causal attribution · 2.0parametric global model · 0.2non-parametric texture model · 0.2tied factor analysis · 0.1non-linear manifold modeling · 0.1generative modeling · 0.1probabilistic spatial density model · 0.1graph cuts · 0.1
| Year | Publication | Venue | Position |
|---|---|---|---|
| 2026 | AgentGraph: Trace-to-Graph Platform for Interactive Analysis and Robustness Testing in Agentic AI SystemsabstractModern Agentic AI systems plan, reason, and act across multiple steps, creating execution patterns that are difficult to interpret. Existing observability platforms track prompt I/O and operational metrics but require manual inspection of traces to reconstruct structure and reasoning. We present AgentGraph, which converts execution logs into interactive knowledge graphs and actionable insights. Nodes represent agents, tasks, tools, data inputs/outputs, and humans, while typed edges capture relations such as inputs consumed, tasks delegated or sequenced, tools required or used, outputs produced and delivered, and interventions from agents or humans. Each graph element links to its exact trace span, ensuring verifiability. Building on this representation, AgentGraph enables two analyses: qualitative trace-grounded failure detection and optimisation recommendations, and quantitative robustness evaluation via perturbation testing and causal attribution. Zekun Wu 0003, Seonglae Cho, Cristian E. Muñoz Villalobos, Theo King, Umar Mohammed, Emre Kazim, María Pérez-Ortiz 0001, Sahan Bulathwela, Adriano S. Koshiyama |
AAAI | 5 |
| 2012 | Probabilistic Models for Inference about IdentityabstractMany face recognition algorithms use "distance-based" methods: Feature vectors are extracted from each face and distances in feature space are compared to determine matches. In this paper, we argue for a fundamentally different approach. We consider each image as having been generated from several underlying causes, some of which are due to identity (latent identity variables, or LIVs) and some of which are not. In recognition, we evaluate the probability that two faces have the same underlying identity cause. We make these ideas concrete by developing a series of novel generative models which incorporate both within-individual and between-individual variation. We consider both the linear case, where signal and noise are represented by a subspace, and the nonlinear case, where an arbitrary face manifold can be described and noise is position-dependent. We also develop a "tied" version of the algorithm that allows explicit comparison of faces across quite different viewing conditions. We demonstrate that our model produces results that are comparable to or better than the state of the art for both frontal face recognition and face recognition under varying pose. Simon Prince, Yun Fu 0002, Umar Mohammed, James H. Elder |
IEEE Trans. Pattern Anal. Mach. Intell. | 4 |
| 2009 | Scene shape priors for superpixel segmentationabstractUnsupervised over-segmentation of an image into super-pixels is a common preprocessing step for image parsing algorithms. Superpixels are used as both regions of support for feature vectors and as a starting point for the final segmentation. In this paper we investigate incorporating a priori information into superpixel segmentations. We learn a probabilistic model that describes the spatial density of the object boundaries in the image. We then describe an over-segmentation algorithm that partitions this density roughly equally between superpixels whilst still attempting to capture local object boundaries. We demonstrate this approach using road scenes where objects in the center of the image tend to be more distant and smaller than those at the edge. We show that our algorithm successfully learns this foveated spatial distribution and can exploit this knowledge to improve the segmentation. Lastly, we introduce a new metric for evaluating vision labeling problems. We measure performance on a challenging real-world dataset and illustrate the limitations of conventional evaluation metrics. Alastair Philip Moore, Simon Prince, Jonathan Warrell, Umar Mohammed, Graham Jones |
ICCV | 4 |
| 2009 | Visio-lization: generating novel facial imagesabstractOur goal is to generate novel realistic images of faces using a model trained from real examples. This model consists of two components: First we consider face images as samples from a texture with spatially varying statistics and describe this texture with a local non-parametric model. Second, we learn a parametric global model of all of the pixel values. To generate realistic faces, we combine the strengths of both approaches and condition the local non-parametric model on the global parametric model. We demonstrate that with appropriate choice of local and global models it is possible to reliably generate new realistic face images that do not correspond to any individual in the training data. We extend the model to cope with considerable intra-class variation (pose and illumination). Finally, we apply our model to editing real facial images: we demonstrate image in-painting, interactive techniques for improving synthesized images and modifying facial expressions. Umar Mohammed, Simon Prince, Jan Kautz |
ACM Trans. Graph. | 1 |
| 2008 | Superpixel latticesabstractUnsupervised over-segmentation of an image into superpixels is a common preprocessing step for image parsing algorithms. Ideally, every pixel within each superpixel region will belong to the same real-world object. Existing algorithms generate superpixels that forfeit many useful properties of the regular topology of the original pixels: for example, the nth superpixel has no consistent position or relationship with its neighbors. We propose a novel algorithm that produces superpixels that are forced to conform to a grid (a regular superpixel lattice). Despite this added topological constraint, our algorithm is comparable in terms of speed and accuracy to alternative segmentation approaches. To demonstrate this, we use evaluation metrics based on (i) image reconstruction (ii) comparison to human-segmented images and (iii) stability of segmentation over subsequent frames of video sequences. Alastair Philip Moore, Simon Prince, Jonathan Warrell, Umar Mohammed, Graham Jones |
CVPR | 4 |