Africa
Optimizing Adaptive Experiments: A Unified Approach to Regret Minimization and Best-Arm Identification
Practitioners conducting adaptive experiments often encounter two competing priorities: reducing the cost of experimentation by effectively assigning treatments during the experiment itself, and gathering information swiftly to conclude the experiment and implement a treatment across the population. Currently, the literature is divided, with studies on regret minimization addressing the former priority in isolation, and research on best-arm identification focusing solely on the latter. This paper proposes a unified model that accounts for both within-experiment performance and post-experiment outcomes. We then provide a sharp theory of optimal performance in large populations that unifies canonical results in the literature. This unification also uncovers novel insights. For example, the theory reveals that familiar algorithms, like the recently proposed top-two Thompson sampling algorithm, can be adapted to optimize a broad class of objectives by simply adjusting a single scalar parameter. In addition, the theory reveals that enormous reductions in experiment duration can sometimes be achieved with minimal impact on both within-experiment and post-experiment regret.
Developing an Optimal Model for Predicting the Severity of Wheat Stem Rust (Case study of Arsi and Bale Zone)
This research utilized three types of artificial neural network (ANN) methodologies, namely Backpropagation Neural Network (BPNN) with varied training, transfer, divide, and learning functions; Radial Basis Function Neural Network (RBFNN); and General Regression Neural Network (GRNN), to forecast the severity of stem rust. It considered parameters such as mean maximum temperature, mean minimum temperature, mean rainfall, mean average temperature, mean relative humidity, and different wheat varieties. The statistical analysis revealed that GRNN demonstrated effective predictive capability and required less training time compared to the other models. Additionally, the results indicated that total seasonal rainfall positively influenced the development of wheat stem rust. Keywords: Wheat stem rust, Back propagation neural network, Radial Basis Function Neural Network, General Regression Neural Network. 1. Introduction Wheat is among the major cereal crops cultivated in Ethiopia. Ethiopia is the second largest producer of wheat in sub-Saharan Africa [1]. The crop has considered as the main staple food of Ethiopian population particularly in highlands of the country [2],where it has produced in a large volume and 95% of the total production is produced by small scale farmers.
World leaders' responses to conflict imperil the rules-based world order
The world is heading towards a dangerous place where selective government outrage and "a la carte" application of international law are becoming the norm. The result is already damning: a crisis of credibility and the erosion of trust in international institutions and governments, putting in peril the rules-based world order. As the heads of Amnesty International and Center for Civilians in Conflict, two of the world's most prominent organisations for human rights and protection of civilians, we have a simple demand for the world leaders who will be coming together on Friday for the 2024 Munich Security Conference: Protect international humanitarian and international human rights laws which are the best tools we have for protecting civilians in times of conflict, and stop creating exceptions that weaken rights protection and endanger global security and stability. Unfortunately, in 2023, world leaders responded unevenly to the countless violations of international humanitarian and human rights law we witnessed in various conflicts across the world. They expressed outrage at the crimes committed by some warring parties while offering diplomatic cover for others.
After months fighting Houthis on the USS Eisenhower, sailors face a new kind of sea threat
Kirk Lippold discusses the reported three U.S. strikes against Houthis in Yemen on'Your World.' Sailors aboard the aircraft carrier USS Dwight D. Eisenhower and its accompanying warships have spent four months straight at sea defending against ballistic missiles and flying attack drones fired by Iranian-backed Houthis, and are now more regularly also defending against a new threat -- fast unmanned vessels that are fired at them through the water. While the Houthis have launched unmanned surface vessels, or USVs, in the past against Saudi coalition forces that have intervened in Yemen's civil war, they were used for the first time against U.S. military and commercial vessels in the Red Sea on Jan. 4. In the weeks since, the Navy has had to intercept and destroy multiple USVs. It's "more of an unknown threat that we don't have a lot of intel on, that could be extremely lethal -- an unmanned surface vessel," said Rear Adm. Marc Miguez, commander of Carrier Strike Group Two, of which the Eisenhower is the flagship. The Houthis "have ways of obviously controlling them just like they do the (unmanned aerial vehicles), and we have very little little fidelity as to all the stockpiles of what they have USV-wise," Miguez said.
Improving Black-box Robustness with In-Context Rewriting
O'Brien, Kyle, Ng, Nathan, Puri, Isha, Mendez, Jorge, Palangi, Hamid, Kim, Yoon, Ghassemi, Marzyeh, Hartvigsen, Thomas
Machine learning models often excel on in-distribution (ID) data but struggle with unseen out-of-distribution (OOD) inputs. Most techniques for improving OOD robustness are not applicable to settings where the model is effectively a black box, such as when the weights are frozen, retraining is costly, or the model is leveraged via an API. Test-time augmentation (TTA) is a simple post-hoc technique for improving robustness that sidesteps black-box constraints by aggregating predictions across multiple augmentations of the test input. TTA has seen limited use in NLP due to the challenge of generating effective natural language augmentations. In this work, we propose LLM-TTA, which uses LLM-generated augmentations as TTA's augmentation function. LLM-TTA outperforms conventional augmentation functions across sentiment, toxicity, and news classification tasks for BERT and T5 models, with BERT's OOD robustness improving by an average of 4.30 percentage points without regressing average ID performance. We explore selectively augmenting inputs based on prediction entropy to reduce the rate of expensive LLM augmentations, allowing us to maintain performance gains while reducing the average number of generated augmentations by 57.76%. LLM-TTA is agnostic to the task model architecture, does not require OOD labels, and is effective across low and high-resource settings. We share our data, models, and code for reproducibility.
QuRating: Selecting High-Quality Data for Training Language Models
Wettig, Alexander, Gupta, Aatmik, Malik, Saumya, Chen, Danqi
Selecting high-quality pre-training data is important for creating capable language models, but existing methods rely on simple heuristics. We introduce QuRating, a method for selecting pre-training data that captures the abstract qualities of texts which humans intuitively perceive. In this paper, we investigate four qualities - writing style, required expertise, facts & trivia, and educational value. We find that LLMs are able to discern these qualities and observe that they are better at making pairwise judgments of texts than at rating the quality of a text directly. We train a QuRater model to learn scalar ratings from pairwise judgments, and use it to annotate a 260B training corpus with quality ratings for each of the four criteria. In our experiments, we select 30B tokens according to the different quality ratings and train 1.3B-parameter language models on the selected data. We find that it is important to balance quality and diversity, as selecting only the highest-rated documents leads to poor results. When we sample using quality ratings as logits over documents, our models achieve lower perplexity and stronger in-context learning performance than baselines. Beyond data selection, we use the quality ratings to construct a training curriculum which improves performance without changing the training dataset. We extensively analyze the quality ratings and discuss their characteristics, biases, and wider implications.
A Data-Driven Supervised Machine Learning Approach to Estimating Global Ambient Air Pollution Concentrations With Associated Prediction Intervals
Berrisford, Liam J, Barbosa, Hugo, Menezes, Ronaldo
Global ambient air pollution, a transboundary challenge, is typically addressed through interventions relying on data from spatially sparse and heterogeneously placed monitoring stations. These stations often encounter temporal data gaps due to issues such as power outages. In response, we have developed a scalable, data-driven, supervised machine learning framework. This model is designed to impute missing temporal and spatial measurements, thereby generating a comprehensive dataset for pollutants including NO$_2$, O$_3$, PM$_{10}$, PM$_{2.5}$, and SO$_2$. The dataset, with a fine granularity of 0.25$^{\circ}$ at hourly intervals and accompanied by prediction intervals for each estimate, caters to a wide range of stakeholders relying on outdoor air pollution data for downstream assessments. This enables more detailed studies. Additionally, the model's performance across various geographical locations is examined, providing insights and recommendations for strategic placement of future monitoring stations to further enhance the model's accuracy.
"Model Cards for Model Reporting" in 2024: Reclassifying Category of Ethical Considerations in Terms of Trustworthiness and Risk Management
Kennedy-Mayo, DeBrae, Gord, Jake
In 2019, the paper entitled "Model Cards for Model Reporting" introduced a new tool for documenting model performance and encouraged the practice of transparent reporting for a defined list of categories. One of the categories detailed in that paper is ethical considerations, which includes the subcategories of data, human life, mitigations, risks and harms, and use cases. We propose to reclassify this category in the original model card due to the recent maturing of the field known as trustworthy AI, a term which analyzes whether the algorithmic properties of the model indicate that the AI system is deserving of trust from its stakeholders. In our examination of trustworthy AI, we highlight three respected organizations - the European Commission's High-Level Expert Group on AI, the OECD, and the U.S.-based NIST - that have written guidelines on various aspects of trustworthy AI. These recent publications converge on numerous characteristics of the term, including accountability, explainability, fairness, privacy, reliability, robustness, safety, security, and transparency, while recognizing that the implementation of trustworthy AI varies by context. Our reclassification of the original model-card category known as ethical considerations involves a two-step process: 1) adding a new category known as trustworthiness, where the subcategories will be derived from the discussion of trustworthy AI in our paper, and 2) maintaining the subcategories of ethical considerations under a renamed category known as risk environment and risk management, a title which we believe better captures today's understanding of the essence of these topics. We hope that this reclassification will further the goals of the original paper and continue to prompt those releasing trained models to accompany these models with documentation that will assist in the evaluation of their algorithmic properties.
SemRel2024: A Collection of Semantic Textual Relatedness Datasets for 14 Languages
Ousidhoum, Nedjma, Muhammad, Shamsuddeen Hassan, Abdalla, Mohamed, Abdulmumin, Idris, Ahmad, Ibrahim Said, Ahuja, Sanchit, Aji, Alham Fikri, Araujo, Vladimir, Ayele, Abinew Ali, Baswani, Pavan, Beloucif, Meriem, Biemann, Chris, Bourhim, Sofia, De Kock, Christine, Dekebo, Genet Shanko, Hourrane, Oumaima, Kanumolu, Gopichand, Madasu, Lokesh, Rutunda, Samuel, Shrivastava, Manish, Solorio, Thamar, Surange, Nirmal, Tilaye, Hailegnaw Getaneh, Vishnubhotla, Krishnapriya, Winata, Genta, Yimam, Seid Muhie, Mohammad, Saif M.
Exploring and quantifying semantic relatedness is central to representing language. It holds significant implications across various NLP tasks, including offering insights into the capabilities and performance of Large Language Models (LLMs). While earlier NLP research primarily focused on semantic similarity, often within the English language context, we instead investigate the broader phenomenon of semantic relatedness. In this paper, we present SemRel, a new semantic relatedness dataset collection annotated by native speakers across 14 languages:Afrikaans, Algerian Arabic, Amharic, English, Hausa, Hindi, Indonesian, Kinyarwanda, Marathi, Moroccan Arabic, Modern Standard Arabic, Punjabi, Spanish, and Telugu. These languages originate from five distinct language families and are predominantly spoken in Africa and Asia -- regions characterised by a relatively limited availability of NLP resources. Each instance in the SemRel datasets is a sentence pair associated with a score that represents the degree of semantic textual relatedness between the two sentences. The scores are obtained using a comparative annotation framework. We describe the data collection and annotation processes, related challenges when building the datasets, and their impact and utility in NLP. We further report experiments for each language and across the different languages.
LogELECTRA: Self-supervised Anomaly Detection for Unstructured Logs
Yamanaka, Yuuki, Takahashi, Tomokatsu, Minami, Takuya, Nakajima, Yoshiaki
System logs are some of the most important information for the maintenance of software systems, which have become larger and more complex in recent years. The goal of log-based anomaly detection is to automatically detect system anomalies by analyzing the large number of logs generated in a short period of time, which is a critical challenge in the real world. Previous studies have used a log parser to extract templates from unstructured log data and detect anomalies on the basis of patterns of the template occurrences. These methods have limitations for logs with unknown templates. Furthermore, since most log anomalies are known to be point anomalies rather than contextual anomalies, detection methods based on occurrence patterns can cause unnecessary delays in detection. In this paper, we propose LogELECTRA, a new log anomaly detection model that analyzes a single line of log messages more deeply on the basis of self-supervised anomaly detection. LogELECTRA specializes in detecting log anomalies as point anomalies by applying ELECTRA, a natural language processing model, to analyze the semantics of a single line of log messages. LogELECTRA outperformed existing state-of-the-art methods in experiments on the public benchmark log datasets BGL, Sprit, and Thunderbird.