arXiv subjects

Abhishek Samanta

Publications and source records attributed to Abhishek Samanta.

3 recordsLinked to original sources

arXiv2023

Test-time Training for Data-efficient UCDR

Image retrieval under generalized test scenarios has gained significant momentum in literature, and the recently proposed protocol of Universal Cross-domain Retrieval is a pioneer in this direction. A common practice in any such generalized classification or retrieval algorithm is to exploit samples from many domains during training to learn a domain-invariant representation of data. Such criterion is often restrictive, and thus in this work, for the first time, we explore the generalized retrieval problem in a data-efficient manner. Specifically, we aim to generalize any pre-trained cross-domain retrieval network towards any unknown query domain/category, by means of adapting the model on the test data leveraging self-supervised learning techniques. Toward that goal, we explored different self-supervised loss functions~(for example, RotNet, JigSaw, Barlow Twins, etc.) and analyze their effectiveness for the same. Extensive experiments demonstrate the proposed approach is simple, easy to implement, and effective in handling data-efficient UCDR.

cs.CV↗

arXiv2014

Deterministic Blind Rendezvous in Cognitive Radio Networks

Blind rendezvous is a fundamental problem in cognitive radio networks. The problem involves a collection of agents (radios) that wish to discover each other in the blind setting where there is no shared infrastructure and they initially have no knowledge of each other. Time is divided into discrete slots; spectrum is divided into discrete channels, $\{1,2,..., n\}$. Each agent may access a single channel in a single time slot and we say that two agents rendezvous when they access the same channel in the same time slot. The model is asymmetric: each agent $A_i$ may only use a particular subset $S_i$ of the channels and different agents may have access to different subsets of channels. The goal is to design deterministic channel hopping schedules for each agent so as to guarantee rendezvous between any pair of agents with overlapping channel sets. Two independent sets of authors, Shin et al. and Lin et al., gave the first constructions guaranteeing asynchronous blind rendezvous in $O(n^2)$ and $O(n^3)$ time, respectively. We present a substantially improved construction guaranteeing that any two agents, $A_i$, $A_j$, will rendezvous in $O(|S_i| |S_j| \log\log n)$ time. Our results are the first that achieve nontrivial dependence on $|S_i|$, the size of the set of available channels. This allows us, for example, to save roughly a quadratic factor over the best previous results in the important case when channel subsets have constant size. We also achieve the best possible bound of $O(1)$ time for the symmetric situation; previous works could do no better than $O(n)$. Using the probabilistic method and Ramsey theory we provide evidence in support of our suspicion that our construction is asymptotically optimal for small size channel subsets: we show both a $c |S_i||S_j|$ lower bound and a $c \log\log n$ lower bound when $|S_i|, |S_j| \leq n/2$.

cs.NI↗

arXiv2010

Fault Tolerant Wireless Sensor MAC Protocol for Efficient Collision Avoidance

In sensor networks communication by broadcast methods involves many hazards, especially collision. Several MAC layer protocols have been proposed to resolve the problem of collision namely ARBP, where the best achieved success rate is 90%. We hereby propose a MAC protocol which achieves a greater success rate (Success rate is defined as the percentage of delivered packets at the source reaching the destination successfully) by reducing the number of collisions, but by trading off the average propagation delay of transmission. Our proposed protocols are also shown to be more energy efficient in terms of energy dissipation per message delivery, compared to the currently existing protocol.

cs.NI↗