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Last-minute holiday gift guide: 29 editor-approved gadgets for everyone on your list

Popular Science

Is someone on your list hard to shop for? We've got a ton of great options for just about anyone. And grab a little something for yourself. We may earn revenue from the products available on this page and participate in affiliate programs. Some people get their holiday shopping done on a responsible schedule. They budget, strategize, and stay organized for a stress-free season. Last-minute holiday shopping is a time-honored tradition, and we're here to help make it a lot easier.


A Viral Chinese Wristband Claims to Zap You Awake. The Public Says 'No Thanks'

WIRED

The Public Says'No Thanks' The maker of the eCoffee Energyband says it electrically stimulates your nerves to keep you alert. Researchers are skeptical, and critics see it as a way for China's bosses to keep workers productive. Forget coffee, you can now stay alert by strapping on a wristband that lightly zaps you awake. That's what eCoffee Energyband, a Chinese gadget that sells for just over $100, is claiming to do. First released in late 2023, the product is a lightweight wearable with two electrode pads that sit against the inner wrist.



Picking a Representative Set of Solutions in Multiobjective Optimization: Axioms, Algorithms, and Experiments

Boehmer, Niclas, Wittmann, Maximilian T.

arXiv.org Artificial Intelligence

Many real-world decision-making problems involve optimizing multiple objectives simultaneously, rendering the selection of the most preferred solution a non-trivial problem: All Pareto optimal solutions are viable candidates, and it is typically up to a decision maker to select one for implementation based on their subjective preferences. To reduce the cognitive load on the decision maker, previous work has introduced the Pareto pruning problem, where the goal is to compute a fixed-size subset of Pareto optimal solutions that best represent the full set, as evaluated by a given quality measure. Reframing Pareto pruning as a multiwinner voting problem, we conduct an axiomatic analysis of existing quality measures, uncovering several unintuitive behaviors. Motivated by these findings, we introduce a new measure, directed coverage. We also analyze the computational complexity of optimizing various quality measures, identifying previously unknown boundaries between tractable and intractable cases depending on the number and structure of the objectives. Finally, we present an experimental evaluation, demonstrating that the choice of quality measure has a decisive impact on the characteristics of the selected set of solutions and that our proposed measure performs competitively or even favorably across a range of settings.



Learning CNF formulas from uniform random solutions in the local lemma regime

Feng, Weiming, Yang, Xiongxin, Yu, Yixiao, Zhang, Yiyao

arXiv.org Machine Learning

We study the problem of learning a $n$-variables $k$-CNF formula $Φ$ from its i.i.d. uniform random solutions, which is equivalent to learning a Boolean Markov random field (MRF) with $k$-wise hard constraints. Revisiting Valiant's algorithm (Commun. ACM'84), we show that it can exactly learn (1) $k$-CNFs with bounded clause intersection size under Lovász local lemma type conditions, from $O(\log n)$ samples; and (2) random $k$-CNFs near the satisfiability threshold, from $\widetilde{O}(n^{\exp(-\sqrt{k})})$ samples. These results significantly improve the previous $O(n^k)$ sample complexity. We further establish new information-theoretic lower bounds on sample complexity for both exact and approximate learning from i.i.d. uniform random solutions.


2025 holiday gift guide: 30 editor-approved presents for everyone on your list

Popular Science

Whether you're shopping for your closest friend who has everything or a grumpy family member who criticizes every gift you've ever given, we have the best suggestions for you. We may earn revenue from the products available on this page and participate in affiliate programs. Your friends and family deserve the best possible gifts. But, shopping can be tricky. You don't want to give them something impersonal, like a gift card, but you also can't resort to drawing them a card with a Christmas tree on it again. It's our job to find the best products and deals, so we've spent way too much time digging up a ton of products that pretty much anyone would like.