Technology
Researchers Develop Algorithm for Optimal Decision Making Under Heavy-tailed Noisy Rewards
By Adedapo Adesanya
The exploration algorithms for stochastic multi-armed bandits (MABs)–sequential decision-making problems under uncertain environments–typically assume light-tailed distributions for reward noises.
However, real-world datasets often show heavy-tailed noise. In light of this, researchers from Korea propose an algorithm that can achieve minimax optimality (minimum loss under maximum loss scenario) with minimal prior information.
Superior to existing algorithms, the new algorithm has potential applications in autonomous trading and personalized recommendation systems.
In data science, researchers typically deal with data that contain noisy observations. An important problem explored by data scientists in this context is the problem of sequential decision-making. This is commonly known as a “stochastic multi-armed bandit” or (stochastic MAB).
Here, an intelligent agent sequentially explores and selects actions based on noisy rewards under an uncertain environment. Its goal is to minimize cumulative regret–the difference between the maximum reward and the expected reward of selected actions. A smaller regret implies more efficient decision-making.
Most existing studies on stochastic MABs have performed regret analysis under the assumption that the reward noise follows a light-tailed distribution. However, many real-world datasets, in fact, show a heavy-tailed noise distribution.
These include user behavioural pattern data used for developing personalized recommendation systems, stock price data for automatic transaction development, and sensor data for autonomous driving.
In a recent study, Assistant Professor Kyungjae Lee of Chung-Ang University and Assistant Professor Sungbin Lim of the Ulsan Institute of Science and Technology, both in Korea, addressed this issue. In their theoretical analysis, they proved that the existing algorithms for stochastic MABs were sub-optimal for heavy-tailed rewards.
More specifically, the methods employed in these algorithms–robust upper confidence bound (UCB) and adaptively perturbed exploration (APE) with unbounded perturbation–do not guarantee a minimax (minimization of maximum possible loss) optimality.
“Based on this analysis, minimax optimal robust (MR) UCB and APE methods have been proposed. MR-UCB utilizes a tighter confidence bound of robust mean estimators, and MR-APE is its randomized version. It employs bounded perturbation whose scale follows the modified confidence bound in MR-UCB,” explains Dr Lee, speaking of their work, which was published in the IEEE Transactions on Neural Networks and Learning Systems on 14 September 2022.
The researchers next derived gap-dependent and independent upper bounds of the cumulative regret. For both the proposed methods, the latter value matches the lower bound under the heavy-tailed noise assumption, thereby achieving minimax optimality.
Further, the new methods require minimal prior information and depend only on the maximum order of the bounded moment of rewards. In contrast, the existing algorithms require the upper bound of this moment a priori–information that may not be accessible in many real-world problems.
Having established their theoretical framework, the researchers tested their methods by performing simulations under Pareto and Fréchet noises. They found that MR-UCB consistently outperformed other exploration methods and was more robust with an increase in the number of actions under heavy-tailed noise.
Further, the duo verified their approach for real-world data using a cryptocurrency dataset, showing that MR-UCB and MR-APE were beneficial–minimax optimal regret bounds and minimal prior knowledge–in tackling heavy-tailed synthetic and real-world stochastic MAB problems.
“Being vulnerable to heavy-tailed noise, the existing MAB algorithms show poor performance in modelling stock data. They fail to predict big hikes or sudden drops in stock prices, causing huge losses. In contrast, MR-APE can be used in autonomous trading systems with stable expected returns through stock investment,” comments Dr Lee, discussing the potential applications of the present work.
“Additionally, it can be applied to personalized recommendation systems since behavioural data shows heavy-tailed noise. With better predictions of individual behaviour, it is possible to provide better recommendations than conventional methods, which can maximize the advertising revenue,” he concludes.
By Modupe Gbadeyanka
Bharti Airtel has crossed 650 million mobile subscribers worldwide to emerge as the world’s second-largest telecommunications firm.
The Indian company has operations in several countries, including Nigeria, where it has continued to scale infrastructure at a pace unmatched in its recent history.
Over the past three years, the telco has increased its national site count from just above 13,000 to nearly 17,200 sites, including more than 1,560 added in the last 12 months.
This expansion deepens capacity in high-demand corridors and extends high-speed coverage to previously underserved regions.
The latest industry data from the Nigerian Communications Commission (NCC) underscores the significance of this growth. As of December 2025, Nigeria recorded 145,141 base stations across 2G, 3G, 4G and 5G layers.
Of this national infrastructure, Airtel accounts for 46,918 base-station layers, reflecting its substantial contribution to the country’s radio access network and its push to absorb rising data consumption.
Nearly 99 per cent of Airtel Nigeria’s sites are now 4G-enabled, positioning the operator as one of the few with a near-ubiquitous high-speed broadband footprint. Thousands of sites have been upgraded for capacity in the past year alone, enabling improved speeds and more stable performance during peak usage.
That expansion underpins Nigeria’s rising internet adoption. According to the latest regulator figures, Nigeria’s internet penetration recently climbed above 50 per cent, with Airtel recording among the largest monthly increases in new internet subscribers, driven by network upgrades across states and rural corridors.
Strategic Connectivity and Redundancy
Airtel is also tackling a critical infrastructure challenge for the Nigerian digital economy: reliance on a single international internet gateway. The company is advancing plans for its second submarine cable internet breakout point at Kwa Ibo in Akwa Ibom State, early in the 2Africa cable system rollout, to provide faster and more resilient national connectivity across regions. This significant investment aligns with global best practices in network diversity and redundancy, ensuring a more stable digital experience for consumers and enterprises alike.
Digital Finance at Scale: SmartCash
Airtel’s digital finance arm, SmartCash, has gained traction in Nigeria’s competitive mobile money ecosystem, now serving over 3 million active users. The platform is supported by an expansive agent network and digital services that lower barriers for everyday financial transactions and savings.
Outstanding Human Touch: Retail Reach
Across Nigeria, Airtel’s retail distribution network stands as one of the sector’s most extensive, with approximately 4,000 exclusive outlets bringing services, support, and products closer to customers in small towns, communities, and high-traffic urban hubs. That footprint drives both access and engagement in a market where localised presence remains a competitive differentiator.
As Nigeria’s digital economy continues to evolve, Airtel is committed to sustained innovation — from expanded fibre backbones and advanced mobile broadband to future-ready services that include satellite-enabled solutions and enterprise-grade digital platforms. These efforts help ensure that connectivity, commerce, and creativity thrive across Nigeria and beyond.
By Adedapo Adesanya
Nigeria has set 2028 and 2029 as the timeline for the deployment of its new satellites, NIGCOMSAT-2A and 2B, respectively.
The Managing Director of NIGCOMSAT, which is Nigerian Communications Satellite Limited and the premier satellite operator in Nigeria, Mrs Jane Nkechi Egerton-Idehen, disclosed this at the second Nigerian Satellite Week in Abuja on Monday. She noted that the development is expected to boost military intelligence, surveillance, and regional connectivity.
“For 2A and 2B, we have started the process. We have closed the tender and are now back into the financing and implementation stage. 2A is built to come up in 2028, and 2B for 2029.
“When they are up and running, they are expected to provide security within the borders and neighbouring countries. They will support the security agencies because data collection and intelligence in real time is important. Satellites like communication satellites allow that, irrespective of where they are,” she said.
In his remarks, the Minister of Communications and Digital Economy, Mr Bosun Tijani, said the satellites form part of the nation’s strategy to strengthen digital infrastructure.
Mr Tijani explained that the satellites will complement ongoing investments in 90,000 kilometres of fibre-optic cable and nearly 4,000 telecom towers, which are being rolled out nationwide and extended to neighbouring countries, including Cameroon, Niger, Chad, Burkina Faso, and the Republic of Benin.
He stressed that satellite technology is critical for national development, affecting education, agriculture, business, and emergency response.
“The president’s approval of NIGCOMSAT-2A and 2B demonstrates a clear commitment to building the future. These satellites will enhance security, connect remote communities, and extend our fibre-optic network into neighbouring countries,” he said.
“Some of these neighbouring countries pay up to ten times more for internet capacity than Lagos. Extending our fibre network will not only improve connectivity but also enhance border security and regional collaboration.
“Satellite technology affects everything, from how a child in a rural community accesses the internet to how farmers make critical decisions and how businesses operate across distance,” the Minister said.
Also speaking, the Chief of Army Staff (COAS), Lieutenant General Waidi Shaibu, welcomed the development, saying the military will leverage the satellites for operational efficiency.
“The Nigerian Army will continue to use space assets to improve intelligence gathering, surveillance, and operational coordination across all theatres of operation,” he said at the event, represented by Major General Kennedy Osemwegie, Commander of the Nigerian Army Cyber Warfare Command (NACWC).
By Modupe Gbadeyanka
A partnership to advance digital payments and financial inclusion across East Africa has been strengthened between Interswitch and KCB Group.
Both parties have agreed to expand digital payment infrastructure and deliver innovative financial solutions that meet the evolving needs of individuals, businesses, and institutions across the region.
The aim is to accelerate seamless, secure, and inclusive digital payments in East Africa, where the leading Africa-focused integrated payments and digital commerce enabler, Interswitch, recently announced an expansion of Verve card acceptance footprint, leveraging its consolidated partnership with KCB Group, Kenya’s largest financial services group by assets, following a similar move in Uganda through the local KCB Franchise in February 2022.
During a recent executive engagement at KCB Group headquarters in Nairobi, the chief executive of Interswitch, Mr Mitchell Elegbe, held high-level discussions with KCB leadership, including its chief executive, Paul Russo.
At the core of the strengthened collaboration is the integration of Interswitch’s robust payment rails, card scheme, and emerging digital token solutions with KCB Group’s expansive regional footprint and trusted banking franchise.
This integration enables the acceptance of Verve cards and tokenised payment solutions across KCB’s extensive merchant point-of-sale network in Kenya and Uganda, significantly enhancing everyday usability for customers while strengthening KCB’s digitally driven retail payments offering.
The consolidated partnership is expected to drive increased merchant acquisition, improve interoperability across payment ecosystems, and expand access to secure, cashless transactions. It also reinforces both organisations’ shared objective of deepening financial inclusion and accelerating digital commerce across East Africa.
“Our collaboration with KCB Group represents a powerful alignment of vision and capability. By combining our technology-driven payment solutions with KCB’s strong regional presence, we are unlocking new opportunities to scale access, drive innovation, and deliver greater value to customers across East Africa,” Mr Elegbe stated.
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