Institution profile

University of Bucharest

Academic institutioneurope · ro
Official website
Research library124linked papers
Opportunities0open roles
Selected work

Representative Papers

Rip Current Segmentation: A Novel Benchmark and YOLOv8 Baseline Results

Jun 01, 20232023 IEEE/CVF Conference on Computer Vision and Pattern Recognition Workshops (CVPRW)

This paper addresses the challenging problem of automated rip current detection in beach environments. We formally introduce the task of instance-level rip current segmentation—a novel formulation for fine-grained, pixel-accurate identification. To support this task, we construct the first high-quality multimodal benchmark dataset, comprising 2,466 images with polygon annotations and 17 drone-captured video sequences (24K frames) with frame-level mask annotations. Methodologically, we adapt the YOLOv8 instance segmentation architecture into a lightweight, real-time framework capable of processing both static images and video streams. Our optimized YOLOv8-nano variant achieves 88.94% mAP₅₀ on the validation set and 81.21% macro-average precision on test videos. All code, pre-trained models, and annotated data are publicly released. This work establishes a deployable baseline—suitable for edge devices—for intelligent, real-time rip current monitoring, thereby advancing both benchmarking and practical deployment in coastal safety applications.

18 citationsRead paper

Certificates in P and Subquadratic-Time Computation of Radius, Diameter, and all Eccentricities in Graphs

Mar 13, 2018

Computing graph radius, diameter, and all eccentricities is conjectured to require quadratic time under the Strong Exponential Time Hypothesis (SETH). Method: We introduce the notion of *node certificates*—compact auxiliary structures capturing local graph topology sufficient to infer global eccentricities—and establish a tight relationship between certificate size and graph probing complexity. Building on this, we design a randomized subquadratic algorithmic framework supporting queries from one-hop to all-pairs distances, analyzed via primal-dual techniques to yield the first parameterized theoretical guarantees for subquadratic eccentricity computation. Results: Empirical evaluation shows node certificates are significantly smaller than the graph size in real-world networks; our algorithm achieves tight subquadratic time complexity (e.g., $O(n^2 / log n)$) across diverse graph classes; it substantially improves practical runtime while enabling rigorous, provable performance bounds.

11 citationsRead paper

Finding Small Complete Subgraphs Efficiently

Aug 22, 2023International Workshop on Combinatorial Algorithms

This paper addresses the efficient enumeration of small cliques—particularly triangles and $K_ell$ for $ell geq 3$—in sparse graphs. Methodologically, it introduces a minimalist triangle enumeration algorithm derived from first principles, achieving the $O(malpha)$ time bound, where $alpha$ denotes the graph’s arboricity; it also provides the first rigorous proof that the Chiba–Nishizeki algorithm attains a tight time lower bound for $K_ell$ enumeration, and establishes improved arboricity-sensitive counting and detection bounds for $ell geq 4$. Crucially, the approach abandons reliance on the Nash–Williams theorem, instead reconstructing a combinatorial framework grounded directly in arboricity properties. Theoretically, the results are optimal and asymptotically tight. Experimentally, the triangle enumerator significantly outperforms baselines, while for $K_ell$ with $ell geq 7$, it achieves consistent speedups on high-arboricity graphs.

3 citations1 influentialRead paper
Recent publications

Latest Papers