Africa
Supervised Hypergraph Reconstruction
We study an issue commonly seen with graph data analysis: many real-world complex systems involving high-order interactions are best encoded by hypergraphs; however, their datasets often end up being published or studied only in the form of their projections (with dyadic edges). To understand this issue, we first establish a theoretical framework to characterize this issue's implications and worst-case scenarios. The analysis motivates our formulation of the new task, supervised hypergraph reconstruction: reconstructing a real-world hypergraph from its projected graph, with the help of some existing knowledge of the application domain. To reconstruct hypergraph data, we start by analyzing hyperedge distributions in the projection, based on which we create a framework containing two modules: (1) to handle the enormous search space of potential hyperedges, we design a sampling strategy with efficacy guarantees that significantly narrows the space to a smaller set of candidates; (2) to identify hyperedges from the candidates, we further design a hyperedge classifier in two well-working variants that capture structural features in the projection. Extensive experiments validate our claims, approach, and extensions. Remarkably, our approach outperforms all baselines by an order of magnitude in accuracy on hard datasets. Our code and data can be downloaded from bit.ly/SHyRe.
How Do Java Mutation Tools Differ?
We adopted a Delphi method, which is commonly used when the problem under analysis can benefit from collective and subjective judgments or decisions and when group dynamics do not allow for effective communication (for example, time differences, distance).14 Three of the authors, in weekly meetings, iteratively analyzed the extracted data, resolved ambiguity, and converged onto the final abstraction shown in Table 1. Based on a final data analysis, we made three key observations.
The Tiny and Nightmarishly Efficient Future of Drone Warfare
On Saturday, October 29, a Russian fleet on the Black Sea near Sevastopol was attacked by 16 drones--nine in the air and seven in the water. Purportedly launched by Ukraine, no one knows how much damage was done, but video shot by the attacking drones showed that the vessels were unable to avoid being hit. In response to that and other successful attacks, Russia has retaliated with scores of missiles and Iranian-built Shahed-136 drones aimed at electrical and water systems throughout Ukraine. Despite daily reports of lands taken or lands liberated in the nine-month war, the conflict has been largely fought in the air, with artillery shells, rockets, cruise missiles, and, increasingly, drones. Small, cheap, relatively slow-moving, carrying far less of a wallop than a cruise missile or a 500-pound bomb, the Shaheds in particular have bedeviled Ukraine's otherwise excellent air defenses.
Data Scientist
Proudly "voted the best place to work" in 2021-2022, Foodics, one of the most promising SaaS companies in MENA, was founded in 2014 in KSA with headquarters in Riyadh and offices in the United Arab Emirates Jordan, Kuwait, Egypt, Pakistan, and the Netherlands. FOODICS is the leading Restaurant-Tech company in MENA and a pioneer in the regional F&B industry. Foodics is undergoing rapid expansion across MENA, Pakistan, Africa and Asia, servicing over 20,000 brands, and has achieved three rounds of funding, with the latest raising $170 million in the largest SaaS funding round in MENA, boosting its innovation capabilities to better serve business owners. We provide a cloud-based point-of-sale SaaS ecosystem with tools that help F&B, and retail businesses start, track and grow. Our customers use Foodics to accept payments, track inventory, monitor sales, process orders, digitize menus, manage employees, create analytics and smart reports, provide secure cloud storage and enable the integration of third-party apps.
AI robot Kashef with today's World Cup 2022 predictions โ Day 3
Some humans would say a football match is impossible to predict with any great certainty, but Kashef, our Artificial Intelligence (AI) predictor, would disagree. Kashef has been playing with historical data and performance to predict the results of each game all the way to the final. No surprise that Kashef is backing Lionel Messi and his team to beat the Green Falcons in today's first fixture. Kashef is siding with the Danish Dynamite on this one. However, Tunisia still stands an almost 50 percent chance of picking up at least a point.
MineDojo: Building Open-Ended Embodied Agents with Internet-Scale Knowledge
Fan, Linxi, Wang, Guanzhi, Jiang, Yunfan, Mandlekar, Ajay, Yang, Yuncong, Zhu, Haoyi, Tang, Andrew, Huang, De-An, Zhu, Yuke, Anandkumar, Anima
Autonomous agents have made great strides in specialist domains like Atari games and Go. However, they typically learn tabula rasa in isolated environments with limited and manually conceived objectives, thus failing to generalize across a wide spectrum of tasks and capabilities. Inspired by how humans continually learn and adapt in the open world, we advocate a trinity of ingredients for building generalist agents: 1) an environment that supports a multitude of tasks and goals, 2) a large-scale database of multimodal knowledge, and 3) a flexible and scalable agent architecture. We introduce MineDojo, a new framework built on the popular Minecraft game that features a simulation suite with thousands of diverse open-ended tasks and an internet-scale knowledge base with Minecraft videos, tutorials, wiki pages, and forum discussions. Using MineDojo's data, we propose a novel agent learning algorithm that leverages large pre-trained video-language models as a learned reward function. Our agent is able to solve a variety of open-ended tasks specified in free-form language without any manually designed dense shaping reward. We open-source the simulation suite, knowledge bases, algorithm implementation, and pretrained models (https://minedojo.org) to promote research towards the goal of generally capable embodied agents.
The impact of moving expenses on social segregation: a simulation with RL and ABM
Over the past decades, breakthroughs such as Reinforcement Learning (RL) and Agent-based modeling (ABM) have made simulations of economic models feasible. Recently, there has been increasing interest in applying ABM to study the impact of residential preferences on neighborhood segregation in the Schelling Segregation Model. In this paper, RL is combined with ABM to simulate a modified Schelling Segregation model, which incorporates moving expenses as an input parameter. In particular, deep Q network (DQN) is adopted as RL agents' learning algorithm to simulate the behaviors of households and their preferences. This paper studies the impact of moving expenses on the overall segregation pattern and its role in social integration. A more comprehensive simulation of the segregation model is built for policymakers to forecast the potential consequences of their policies.
XPASC: Measuring Generalization in Weak Supervision by Explainability and Association
Mรคrz, Luisa, Asgari, Ehsaneddin, Braune, Fabienne, Zimmermann, Franziska, Roth, Benjamin
Weak supervision is leveraged in a wide range of domains and tasks due to its ability to create massive amounts of labeled data, requiring only little manual effort. Standard approaches use labeling functions to specify signals that are relevant for the labeling. It has been conjectured that weakly supervised models over-rely on those signals and as a result suffer from overfitting. To verify this assumption, we introduce a novel method, XPASC (eXPlainability-Association SCore), for measuring the generalization of a model trained with a weakly supervised dataset. Considering the occurrences of features, classes and labeling functions in a dataset, XPASC takes into account the relevance of each feature for the predictions of the model as well as the associations of the feature with the class and the labeling function, respectively. The association in XPASC can be measured in two variants: XPASC-CHI SQAURE measures associations relative to their statistical significance, while XPASC-PPMI measures association strength more generally. We use XPASC to analyze KnowMAN, an adversarial architecture intended to control the degree of generalization from the labeling functions and thus to mitigate the problem of overfitting. On one hand, we show that KnowMAN is able to control the degree of generalization through a hyperparameter. On the other hand, results and qualitative analysis show that generalization and performance do not relate one-to-one, and that the highest degree of generalization does not necessarily imply the best performance. Therefore methods that allow for controlling the amount of generalization can achieve the right degree of benign overfitting. Our contributions in this study are i) the XPASC score to measure generalization in weakly-supervised models, ii) evaluation of XPASC across datasets and models and iii) the release of the XPASC implementation.
Evaluating COVID-19 Sequence Data Using Nearest-Neighbors Based Network Model
The SARS-CoV-2 coronavirus is the cause of the COVID-19 disease in humans. Like many coronaviruses, it can adapt to different hosts and evolve into different lineages. It is well-known that the major SARS-CoV-2 lineages are characterized by mutations that happen predominantly in the spike protein. Understanding the spike protein structure and how it can be perturbed is vital for understanding and determining if a lineage is of concern. These are crucial to identifying and controlling current outbreaks and preventing future pandemics. Machine learning (ML) methods are a viable solution to this effort, given the volume of available sequencing data, much of which is unaligned or even unassembled. However, such ML methods require fixed-length numerical feature vectors in Euclidean space to be applicable. Similarly, euclidean space is not considered the best choice when working with the classification and clustering tasks for biological sequences. For this purpose, we design a method that converts the protein (spike) sequences into the sequence similarity network (SSN). We can then use SSN as an input for the classical algorithms from the graph mining domain for the typical tasks such as classification and clustering to understand the data. We show that the proposed alignment-free method is able to outperform the current SOTA method in terms of clustering results. Similarly, we are able to achieve higher classification accuracy using well-known Node2Vec-based embedding compared to other baseline embedding approaches.
A Mixed-Method Approach to Determining Contact Matrices in the Cox's Bazar Refugee Settlement
Walker, Joseph, Aylett-Bullock, Joseph, Shi, Difu, Maina, Allen Gidraf Kahindo, Evers, Egmond Samir, Harlass, Sandra, Krauss, Frank
Contact matrices are an important ingredient in age-structured epidemic models to inform the simulated spread of the disease between sub-groups of the population. These matrices are generally derived using resource-intensive diary-based surveys and few exist in the Global South or tailored to vulnerable populations. In particular, no contact matrices exist for refugee settlements - locations under-served by epidemic models in general. In this paper we present a novel, mixed-method approach, for deriving contact matrices in populations which combines a lightweight, rapidly deployable, survey with an agent-based model of the population informed by census and behavioural data. We use this method to derive the first set of contact matrices for the Cox's Bazar refugee settlement in Bangladesh. The matrices from the refugee settlement show strong banding effects due to different age cut-offs in attendance at certain venues, such as distribution centres and religious sites, as well as the important contribution of the demographic profile of the settlement which was encoded in the model. These can have significant implications to the modelled disease dynamics. To validate our approach, we also apply our method to the population of the UK and compare our derived matrices against well-known contact matrices previously collected using traditional approaches. Overall, our findings demonstrate that our mixed-method approach can address some of the challenges of both the traditional and previously proposed agent-based approaches to deriving contact matrices, and has the potential to be rolled-out in other resource-constrained environments. This work therefore contributes to a broader aim of developing new methods and mechanisms of data collection for modelling disease spread in refugee and IDP settlements and better serving these vulnerable communities.