Horst Samulowitz

dblp:13/2167 · also Horst C. Samulowitz · DBLP profile ↗
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55ranked-venue papers
6as first author
17since 2021 · last 2026
0000-0002-6780-3217ORCID · verified

Domains — the database's venue-derived domains; a paper can count in several

Artificial intelligence and machine learning · 42 · 6 first-author · 9 since 2021Graphics, computer vision, multimedia, augmented reality and games · 23 · 1 first-author · 5 since 2021Databases, data management, data science and information retrieval · 9 · 8 since 2021Theory of computation · 8 · 3 first-authorSoftware engineering, systems software and programming languages · 7 · 2 first-authorHuman-computer interaction and ubiquitous computing · 2 · 1 since 2021Applied, interdisciplinary, general and emerging computing · 1 · 1 since 2021
YearPublicationVenuePosition
2026 Language Model Representations for Efficient Few-Shot Tabular Classification
abstract
The Web is a rich source of structured data in the form of tables, from product catalogs and knowledge bases to scientific datasets. However, the heterogeneity of the structure and semantics of these tables makes it challenging to build a unified method that can effectively leverage the information they contain. Meanwhile, Large language models (LLMs) are becoming an increasingly integral component of web infrastructure for tasks like semantic search. This raises a crucial question: can we leverage these already-deployed LLMs to classify structured data in web-native tables (e.g., product catalogs, knowledge base exports, scientific data portals), avoiding the need for specialized models or extensive retraining? This work investigates a lightweight paradigm, $\textbf{Ta}$ble $\textbf{R}$epresentation with $\textbf{L}$anguage Model~($\textbf{TaRL}$), for few-shot tabular classification that directly utilizes semantic embeddings of individual table rows. We first show that naive application of these embeddings underperforms compared to specialized tabular models. We then demonstrate that their potentials can be unlocked with two key techniques: removing the common component from all embeddings and calibrating the softmax temperature. We show that a simple meta-learner, trained on handcrafted features, can learn to predict an appropriate temperature. This approach achieves performance comparable to state-of-the-art models in low-data regimes ($k \leq 32$) of semantically-rich tables. Our findings demonstrate the viability of reusing existing LLM infrastructure for efficient semantics-driven pathway to reuse existing LLM infrastructure for Web table understanding.
Inwon Kang, Parikshit Ram, Yi Zhou 0015, Horst Samulowitz, Oshani Seneviratne
WWW4
2025 TabSketchFM: Sketch-Based Tabular Representation Learning for Data Discovery Over Data Lakes
abstract
Enterprises have a growing need to identify relevant tables in data lakes; e.g. tables that are unionable, joinable, or subsets of each other. Tabular neural models can be help-ful for such data discovery tasks. In this paper, we present TabSketchFM, a neural tabular model for data discovery over data lakes. First, we propose novel pre-training: a sketch-based approach to enhance the effectiveness of data discovery in neural tabular models. Second, we finetune the pretrained model for identifying unionable, joinable, and subset table pairs and show significant improvement over previous tabular neural models. Third, we present a detailed ablation study to highlight which sketches are crucial for which tasks. Fourth, we use these finetuned models to perform table search; i.e., given a query table, find other tables in a corpus that are unionable, joinable, or that are subsets of the query. Our results demonstrate significant improvements in F1 scores for search compared to state-of-the-art techniques. Finally, we show significant transfer across datasets and tasks establishing that our model can generalize across different tasks and over different data lakes.
Aamod Khatiwada, Harsha Kokel, Ibrahim Abdelaziz, Subhajit Chaudhury, Julian Dolby, Oktie Hassanzadeh, Zhenhan Huang, Tejaswini Pedapati, Horst Samulowitz, Kavitha Srinivas
ICDE9
2024 Effective Data Distillation for Tabular Datasets (Student Abstract)
abstract
Data distillation is a technique of reducing a large dataset into a smaller dataset. The smaller dataset can then be used to train a model which can perform comparably to a model trained on the full dataset. Past works have examined this approach for image datasets, focusing on neural networks as target models. However, tabular datasets pose new challenges not seen in images. A sample in tabular dataset is a one dimensional vector unlike the two (or three) dimensional pixel grid of images, and Non-NN models such as XGBoost can often outperform neural network (NN) based models. Our contribution in this work is two-fold: 1) We show in our work that data distillation methods from images do not translate directly to tabular data; 2) We propose a new distillation method that consistently outperforms the baseline for multiple different models, including non-NN models such as XGBoost.
Inwon Kang, Parikshit Ram, Yi Zhou 0015, Horst Samulowitz, Oshani Seneviratne
AAAI4
2024 Enhancing In-context Learning via Linear Probe Calibration
abstract
In-context learning (ICL) is a new paradigm for natural language processing that utilizes Generative Pre-trained Transformer (GPT)-like models. This approach uses prompts that include in-context demonstrations to generate the corresponding output for a new query input. However, applying ICL in real cases does not scale with the number of samples, and lacks robustness to different prompt templates and demonstration permutations. In this paper, we first show that GPT-like models using ICL result in unreliable predictions based on a new metric based on Shannon entropy. Then, to solve this problem, we propose a new technique called the Linear Probe Calibration (LinC), a method that calibrates the model’s output probabilities, resulting in reliable predictions and improved performance, while requiring only minimal additional samples (as few as five labeled data samples). LinC significantly enhances the ICL test performance of GPT models on various benchmark datasets, with an average improvement of up to 21%, and up to a 50% improvement in some cases, and significantly boosts the performance of PEFT methods, especially in the low resource regime. Moreover, LinC achieves lower expected calibration error, and is highly robust to varying label proportions, prompt templates, and demonstration permutations.
Momin Abbas, Yi Zhou 0015, Parikshit Ram, Nathalie Baracaldo, Horst Samulowitz, Theodoros Salonidis, Tianyi Chen 0002
AISTATS5
2024 Instance-Level Metalearning for Outlier Detection
Long Vu, Peter Kirchner, Charu C. Aggarwal, Horst Samulowitz
IJCAI4
2024 Empirical Evidence on Conversational Control of GUI in Semantic Automation
abstract
This research explores integration of a Large Language Model (LLM) fine-tuned to conversationally control the user interface (UI) for a Semantic Automation Layer (SAL). We condense SAL capabilities from prior work and prioritize with business analysts and data engineers via a Kano model, before implementing a prototypical UI. We augment the UI with our conversational engine and propose In-situ Prompt Engineering and learn from Human Feedback to smoothen the interaction and manipulation of UI through natural language commands. To evaluate the efficacy and usability of conversational control in various use-case scenarios, we conduct and report on an empirical interaction design user study. Our findings provide evidence supporting enhanced user engagement and satisfaction. We also observe significant increase of trust in AI after working with our conversational UI. This work generates areas for further refinement and research towards more intelligent, highly-integrated conversational UIs even beyond our application within Semantic Automation. We discuss our findings and point out next steps paving the way for future research and development in creating more intuitive and adaptive user interfaces.
Daniel Karl I. Weidele, Mauro Martino, Abel N. Valente, Gaetano Rossiello, Hendrik Strobelt, Loraine Franke, Kathryn Alvero, Shayenna Misko, Robin Auer, Sugato Bagchi, Nandana Mihindukulasooriya, Md. Faisal Mahbub Chowdhury, Gregory Bramble, Horst Samulowitz, Alfio Massimiliano Gliozzo, Lisa Amini
IUI14
2024 Feature-Engineered Random Forests
abstract
In this paper, we present a method for constructing a feature-engineered random forest by transforming the features of a given data set using a set of diverse and randomized transforms. The transformed features are then used for creating splits at each node of a random forest. In particular, we use sum-product features because of their strong expressive power. This type of on-the-fly feature engineering has significant advantages over traditional random forests because it adds to the diversity of the splits. Such a diversity further helps in variance reduction; over and above the variance reduction ability offered by traditional random forests. We show the advantages of the proposed approach over traditional random forests and other well-established baselines using extensive experimental evaluation.
Saket Sathe 0001, Charu C. Aggarwal, Horst Samulowitz, Deepak S. Turaga
SDM3
2023 NumJoin: Discovering Numeric Joinable Tables with Semantically Related Columns
abstract
Join discovery is a crucial part of exploration on data lakes. It often involves finding joinable tables that are semantically relevant. However, data lakes often contain numeric tables with unreliable column headers, and ID columns whose text names have been lost. Finding semantically relevant joins over numeric tables is a challenge. State-of-the-art describes join discovery using semantic similarity, but do not consider purely numeric tables. In this paper, we describe a system, NumJoin that includes two novel approaches for discovering joinable tables in a data lake: one that maps tables to knowledge graphs, and another that leverages numeric types and distributions. We demonstrate the effectiveness of NumJoin on a large data lake, including transportation data and finance data.
Pranav Subramaniam, Udayan Khurana, Kavitha Srinivas, Horst Samulowitz
CIKM4
2023 Single-shot General Hyper-parameter Optimization for Federated Learning
Yi Zhou 0015, Parikshit Ram, Theodoros Salonidis, Nathalie Baracaldo, Horst Samulowitz, Heiko Ludwig
ICLR5
2023 SemFORMS: Automatic Generation of Semantic Transforms By Mining Data Science Code
abstract
Careful choice of feature transformations in a dataset can help predictive model performance, data understanding and data exploration. However, finding useful features is a challenge, and while recent Automated Machine Learning (AutoML) systems provide some limited automation for feature engineering or data exploration, it is still mostly done by humans. We demonstrate a system called SemFORMS (Semantic Transforms), which attempts to mine useful expressions for a dataset from access to a repository of code that may target the same dataset/similar dataset. In many enterprises, numerous data scientists often work on the same or similar datasets, but are largely unaware of each other's work. SemFORMS finds appropriate code from such a repository, and normalizes the code to be an actionable transform that can prepended into any AutoML pipeline. We demonstrate SemFORMS operating over example datasets from the OpenML benchmarks where it sometimes leads to significant improvements in AutoML performance.
Ibrahim Abdelaziz, Julian Dolby, Udayan Khurana, Horst Samulowitz, Kavitha Srinivas
IJCAI4
2023 Toward Theoretical Guidance for Two Common Questions in Practical Cross-Validation based Hyperparameter Selection
abstract
We show, to our knowledge, the first theoretical treatments of two common questions in cross-validation based hyperparameter selection: ➀ After selecting the best hyperparameter using a held-out set, we train the final model using all of the training data - since this may or may not improve future generalization error, should one do this? ② During optimization such as via SGD (stochastic gradient descent), we must set the optimization tolerance ρ - since it trades off predictive accuracy with computation cost, how should one set it? Toward these problems, we introduce the hold-in risk (the error due to not using the whole training data), and the model class mis-specification risk (the error due to having chosen the wrong model class) in a theoretical view which is simple, general, and suggests heuristics that can be used when faced with a dataset instance. In proof-of-concept studies in synthetic data where theoretical quantities can be controlled, we show that these heuristics can, respectively, ➀ always perform at least as well as always performing retraining or never performing retraining, ② either improve performance or reduce computational overhead by 2× with no loss in predictive performance. * Full version: https://arxiv.org/abs/2301.05131
Parikshit Ram, Alexander G. Gray, Horst Samulowitz, Gregory Bramble
SDM3
2023 FLASH: Automating federated learning using CASH
abstract
In this paper, we present FLASH, a framework which addresses for the first time the central AutoML problem of Combined Algorithm Selection and HyperParameter (HP) Optimization (CASH) in the context of Federated Learning (FL). To limit training cost, FLASH incrementally adapts the set of algorithms to train based on their projected loss rates, while supporting decentralized (federated) implementation of the embedded hyper-parameter optimization (HPO), model selection and loss calculation problems. We provide a theoretical analysis of the training and validation loss under FLASH, and their tradeoff with the training cost measured as the data wasted in training sub-optimal algorithms. The bounds depend on the degree of dissimilarity between the datasets of the clients, a result of FL restriction that client datasets remain private. Through extensive experimental investigation on several datasets, we evaluate three variants of FLASH, and show that FLASH performs close to centralized CASH methods.
Md. Ibrahim Ibne Alam, Koushik Kar, Theodoros Salonidis, Horst Samulowitz
UAI4
2023 DataRinse: Semantic Transforms for Data preparation based on Code Mining
abstract
Data preparation is a crucial first step to any data analysis problem. This task is largely manual, performed by a person familiar with the data domain. DataRinse is a system designed to extract relevant transforms from large scale static analysis of repositories of code. Our motivation is that in any large enterprise, multiple personas such as data engineers and data scientists work on similar datasets. However, sharing or re-using that code is not obvious and difficult to execute. In this paper, we demonstrate DataRinse to handle data preparation, such that the system recommends code designed to help with the preparation of a column for data analysis more generally. We show that DataRinse does not simply shard expressions observed in code but also uses analysis to group expressions applied to the same field such that related transforms appear coherently to a user. It is a human-in-the-loop system where the users select relevant code snippets produced by DataRinse to apply on their dataset.
Ibrahim Abdelaziz, Julian Dolby, Udayan Khurana, Horst Samulowitz, Kavitha Srinivas
Proc. VLDB Endow.4
2022 Semantic Feature Discovery with Code Mining and Semantic Type Detection
abstract
In recent years, the automation of machine learning and data science (AutoML) has attracted significant attention. One under-explored dimension of AutoML is being able to automatically utilize domain knowledge (such as semantic concepts and relationships) located in historical code or literature from the problem's domain. In this paper, we demonstrate Semantic Feature Discovery, which enables users to interactively explore features semantically discovered from existing data science code and external knowledge. It does so by detecting semantic concepts for a given dataset, and then using these concepts to determine relevant feature engineering operations from historical code and knowledge.
Kavitha Srinivas, Takaaki Tateishi, Daniel Karl I. Weidele, Udayan Khurana, Horst Samulowitz, Toshihiro Takahashi, Dakuo Wang, Lisa Amini
AAAI5
2021 AutoText: An End-to-End AutoAI Framework for Text
abstract
Building models for natural language processing (NLP) tasks remains a daunting task for many, requiring significant technical expertise, efforts, and resources. In this demonstration, we present AutoText, an end-to-end AutoAI framework for text, to lower the barrier of entry in building NLP models. AutoText combines state-of-the-art AutoAI optimization techniques and learning algorithms for NLP tasks into a single extensible framework. Through its simple, yet powerful UI, non-AI experts (e.g., domain experts) can quickly generate performant NLP models with support to both control (e.g., via specifying constraints) and understand learned models.
Arunima Chaudhary, Alayt Issak, Kiran Kate, Yannis Katsis, Abel N. Valente, Dakuo Wang, Alexandre V. Evfimievski, Sairam Gurajada, Ban Kawas, Cristiano Malossi, Lucian Popa 0001, Tejaswini Pedapati, Horst Samulowitz, Martin Wistuba, Yunyao Li 0001
AAAI13
2021 Automated Data Science for Relational Data
abstract
Feature engineering is a crucial but tedious task that requires up to 80% of the total time in data science projects. A significant challenge is when data consists of tables from different data sources, thus data scientists need to wisely aggregate and join tables while performing feature engineering task. In this work, we demonstrate a novel system called OneBM (One Button Machine), that enables data scientists to increase their efficiency with automated feature engineering for relational data. OneBM takes as input a relational dataset with multiple tables and its entity relation diagram (ERD) which can be declared with a novel, easy-to-use drag-and-drop graphical user interface. The system then automatically identifies and executes relevant joins and aggregates in the data, and generates new features with a rich set of transformations for various types of data including but not limited to time-series, sequences, number sets and itemsets, etc. The generated features then can be used by automated model selection and hyper-parameter optimization algorithms to complete a fully end-to-end automated data science (or AutoDS) workflow. A follow-up user evaluation illustrated how data scientists can perform multi-table feature engineering tasks in minutes using our system, compared to repeatedly coding SQL-like queries to transform and aggregate relational data requiring weeks of manual labor for comparable performance. In the live demos we plan to show two use cases with real-world datasets (video demos are available at the links in the footnote): sale prediction1and call center user experience2. Pre-registered partcipants can play with these use-cases and the given datasets via Watson Studio on the cloud.
Hoang Thanh Lam, Beat Buesser, Hong Min, Tran Ngoc Minh, Martin Wistuba, Udayan Khurana, Gregory Bramble, Theodoros Salonidis, Dakuo Wang, Horst Samulowitz
ICDE10
2021 AutoAI-TS: AutoAI for Time Series Forecasting
abstract
A large number of time series forecasting models including traditional statistical models, machine learning models and more recently deep learning have been proposed in the literature. However, choosing the right model along with good parameter values that performs well on a given data is still challenging. Automatically providing a good set of models to users for a given dataset saves both time and effort from using trial-and-error approaches with a wide variety of available models along with parameter optimization. We present AutoAI for Time Series Forecasting (AutoAI-TS) that provides users with a zero configuration (zero-conf) system to efficiently train, optimize and choose best forecasting model among various classes of models for the given dataset. With its flexible zero-conf design, AutoAI-TS automatically performs all the data preparation, model creation, parameter optimization, training and model selection for users and provides a trained model that is ready to use. For given data, AutoAI-TS utilizes a wide variety of models including classical statistical models, Machine Learning (ML) models, statistical-ML hybrid models and deep learning models along with various transformations to create forecasting pipelines. It then evaluates and ranks pipelines using the proposed T-Daub mechanism to choose the best pipeline. The paper describe in detail all the technical aspects of AutoAI-TS along with extensive benchmarking on a variety of real world data sets for various use-cases. Benchmark results show that AutoAI-TS, with no manual configuration from the user, automatically trains and selects pipelines that on average outperform existing state-of-the-art time series forecasting toolkits.
Syed Yousaf Shah, Dhaval Patel 0002, Long Vu, Xuan-Hong Dang, Peter Kirchner, Horst Samulowitz, Gregory Bramble, Wesley M. Gifford, Venkata Sitaramagiridharganesh Ganapavarapu, Roman Vaculín, Petros Zerfos
SIGMOD Conference7
2020 An ADMM Based Framework for AutoML Pipeline Configuration
abstract
We study the AutoML problem of automatically configuring machine learning pipelines by jointly selecting algorithms and their appropriate hyper-parameters for all steps in supervised learning pipelines. This black-box (gradient-free) optimization with mixed integer & continuous variables is a challenging problem. We propose a novel AutoML scheme by leveraging the alternating direction method of multipliers (ADMM). The proposed framework is able to (i) decompose the optimization problem into easier sub-problems that have a reduced number of variables and circumvent the challenge of mixed variable categories, and (ii) incorporate black-box constraints alongside the black-box optimization objective. We empirically evaluate the flexibility (in utilizing existing AutoML techniques), effectiveness (against open source AutoML toolkits), and unique capability (of executing AutoML with practically motivated black-box constraints) of our proposed scheme on a collection of binary classification data sets from UCI ML & OpenML repositories. We observe that on an average our framework provides significant gains in comparison to other AutoML frameworks (Auto-sklearn & TPOT), highlighting the practical advantages of this framework.
Sijia Liu 0001, Parikshit Ram, Deepak Vijaykeerthy, Djallel Bouneffouf 0001, Gregory Bramble, Horst Samulowitz, Dakuo Wang, Andrew Conn 0001, Alexander G. Gray
AAAI6
2020 Autonomous Predictive Modeling via Reinforcement Learning
abstract
Building a robust predictive model requires an array of steps such as data imputation, feature transformations, estimator selection, hyper-parameter search, ensemble construction, amongst others. Due to this vast, complex and heterogeneous space of operations, off-the-shelf optimization methods offer infeasible solutions for realistic response time requirements. In practice, much of the predictive modeling process is conducted by experienced data scientists, who selectively make use of available tools. Over time, they develop an understanding of the behavior of operators, and perform serial decision making under uncertainty, colloquially referred to as educated guesswork. With an unprecedented demand for application of supervised machine learning, there is a call for solutions that automatically search for a suitable combination of operators across these tasks while minimize the modeling error. We introduce a novel system called APRL (Autonomous Predictive modeler via Reinforcement Learning), that uses past experience through reinforcement learning to optimize sequential decision making from within a set of diverse actions under a budget constraint. Our experiments demonstrate the superiority of the proposed approach over known AutoML systems that utilize Bayesian optimization or genetic algorithms.
Udayan Khurana, Horst Samulowitz
CIKM2
2020 Survey on Automated End-to-End Data Science?
abstract
Data science is labor-intensive and human experts are scarce but heavily involved in every aspect of it. This makes data science time consuming and restricted to experts with the resulting quality heavily dependent on their experience and skills. To make data science more accessible and scalable, we need its democratization. Automated Data Science (AutoDS) is aimed towards that goal and is emerging as an important research and business topic. We introduce and define the AutoDS challenge, followed by a proposal of a general AutoDS framework that covers existing approaches but also provides guidance for the development of new methods. We categorize and review the existing literature from multiple aspects of the problem setup and employed techniques. Then we provide several views on how AI could succeed in automating end-to-end AutoDS. We hope this survey can serve as insightful guideline for the AutoDS field and provide inspiration for future research.
Djallel Bouneffouf 0001, Charu C. Aggarwal, Thanh Hoang, Udayan Khurana, Horst Samulowitz, Beat Buesser, Sijia Liu 0001, Tejaswini Pedapati, Parikshit Ram, Ambrish Rawat, Martin Wistuba, Alexander G. Gray
IJCNN5
2019 Deep Learning for Cost-Optimal Planning: Task-Dependent Planner Selection
abstract
As classical planning is known to be computationally hard, no single planner is expected to work well across many planning domains. One solution to this problem is to use online portfolio planners that select a planner for a given task. These portfolios perform a classification task, a well-known and wellresearched task in the field of machine learning. The classification is usually performed using a representation of planning tasks with a collection of hand-crafted statistical features. Recent techniques in machine learning that are based on automatic extraction of features have not been employed yet due to the lack of suitable representations of planning tasks.In this work, we alleviate this barrier. We suggest representing planning tasks by images, allowing to exploit arguably one of the most commonly used and best developed techniques in deep learning. We explore some of the questions that inevitably rise when applying such a technique, and present various ways of building practically useful online portfoliobased planners. An evidence of the usefulness of our proposed technique is a planner that won the cost-optimal track of the International Planning Competition 2018.
Silvan Sievers, Michael Katz 0001, Shirin Sohrabi, Horst Samulowitz, Patrick Ferber
AAAI4
2019 Optimal Exploitation of Clustering and History Information in Multi-armed Bandit
abstract
We consider the stochastic multi-armed bandit problem and the contextual bandit problem with historical observations and pre-clustered arms. The historical observations can contain any number of instances for each arm, and the pre-clustering information is a fixed clustering of arms provided as part of the input. We develop a variety of algorithms which incorporate this offline information effectively during the online exploration phase and derive their regret bounds. In particular, we develop the META algorithm which effectively hedges between two other algorithms: one which uses both historical observations and clustering, and another which uses only the historical observations. The former outperforms the latter when the clustering quality is good, and vice-versa. Extensive experiments on synthetic and real world datasets on Warafin drug dosage and web server selectionfor latency minimization validate our theoretical insights and demonstrate that META is a robust strategy for optimally exploiting the pre-clustering information.
Djallel Bouneffouf 0001, Srinivasan Parthasarathy 0002, Horst Samulowitz, Martin Wistuba
IJCAI3
2019 Human-AI Collaboration in Data Science: Exploring Data Scientists' Perceptions of Automated AI
abstract
The rapid advancement of artificial intelligence (AI) is changing our lives in many ways. One application domain is data science. New techniques in automating the creation of AI, known as AutoAI or AutoML, aim to automate the work practices of data scientists. AutoAI systems are capable of autonomously ingesting and pre-processing data, engineering new features, and creating and scoring models based on a target objectives (e.g. accuracy or run-time efficiency). Though not yet widely adopted, we are interested in understanding how AutoAI will impact the practice of data science. We conducted interviews with 20 data scientists who work at a large, multinational technology company and practice data science in various business settings. Our goal is to understand their current work practices and how these practices might change with AutoAI. Reactions were mixed: while informants expressed concerns about the trend of automating their jobs, they also strongly felt it was inevitable. Despite these concerns, they remained optimistic about their future job security due to a view that the future of data science work will be a collaboration between humans and AI systems, in which both automation and human expertise are indispensable.
Dakuo Wang, Justin D. Weisz, Michael J. Muller, Parikshit Ram, Werner Geyer, Casey Dugan, Yla R. Tausczik, Horst Samulowitz, Alexander G. Gray
Proc. ACM Hum. Comput. Interact.8
2018 Feature Engineering for Predictive Modeling Using Reinforcement Learning
abstract
Feature engineering is a crucial step in the process of predictive modeling. It involves the transformation of given feature space, typically using mathematical functions, with the objective of reducing the modeling error for a given target. However, there is no well-defined basis for performing effective feature engineering. It involves domain knowledge, intuition, and most of all, a lengthy process of trial and error. The human attention involved in overseeing this process significantly influences the cost of model generation. We present a new framework to automate feature engineering. It is based on performance driven exploration of a transformation graph, which systematically and compactly captures the space of given options. A highly efficient exploration strategy is derived through reinforcement learning on past examples.
Udayan Khurana, Horst Samulowitz, Deepak S. Turaga
AAAI2
2018 Dataset Evolver: An Interactive Feature Engineering Notebook
abstract
We present DATASET EVOLVER, an interactive Jupyter notebook-based tool to support data scientists perform feature engineering for classification tasks. It provides users with suggestions on new features to construct, based on automated feature engineering algorithms. Users can navigate the given choices in different ways, validate the impact, and selectively accept the suggestions. DATASET EVOLVER is a pluggable feature engineering framework where several exploration strategies could be added. It currently includes meta-learning based exploration and reinforcement learning based exploration. The suggested features are constructed using well-defined mathematical functions and are easily interpretable. Our system provides a mixed-initiative system of a user being assisted by an automated agent to efficiently and effectively solve the complex problem of feature engineering. It reduces the effort of a data scientist from hours to minutes.
Fatemeh Nargesian, Udayan Khurana, Tejaswini Pedapati, Horst Samulowitz, Deepak S. Turaga
AAAI4
2017 Learning Feature Engineering for Classification
abstract
Feature engineering is the task of improving predictive modelling performance on a dataset by transforming its feature space. Existing approaches to automate this process rely on either transformed feature space exploration through evaluation-guided search, or explicit expansion of datasets with all transformed features followed by feature selection. Such approaches incur high computational costs in runtime and/or memory. We present a novel technique, called Learning Feature Engineering (LFE), for automating feature engineering in classification tasks. LFE is based on learning the effectiveness of applying a transformation (e.g., arithmetic or aggregate operators) on numerical features, from past feature engineering experiences. Given a new dataset, LFE recommends a set of useful transformations to be applied on features without relying on model evaluation or explicit feature expansion and selection. Using a collection of datasets, we train a set of neural networks, which aim at predicting the transformation that impacts classification performance positively. Our empirical results show that LFE outperforms other feature engineering approaches for an overwhelming majority (89%) of the datasets from various sources while incurring a substantially lower computational cost.
Fatemeh Nargesian, Horst Samulowitz, Udayan Khurana, Elias B. Khalil, Deepak S. Turaga
IJCAI2
2016 Deep Learning for Algorithm Portfolios
abstract
It is well established that in many scenarios there is no single solver that will provide optimal performance across a wide range of problem instances. Taking advantage of this observation, research into algorithm selection is designed to help identify the best approach for each problem at hand. This segregation is usually based on carefully constructed features, designed to quickly present the overall structure of the instance as a constant size numeric vector. Based on these features, a plethora of machine learning techniques can be utilized to predict the appropriate solver to execute, leading to significant improvements over relying solely on any one solver. However, being manually constructed, the creation of good features is an arduous task requiring a great deal of knowledge of the problem domain of interest. To alleviate this costly yet crucial step, this paper presents an automated methodology for producing an informative set of features utilizing a deep neural network. We show that the presented approach completely automates the algorithm selection pipeline and is able to achieve significantly better performance than a single best solver across multiple problem domains.
Andrea Loreggia, Yuri Malitsky, Horst Samulowitz, Vijay A. Saraswat
AAAI3
2016 Selecting Near-Optimal Learners via Incremental Data Allocation
abstract
We study a novel machine learning (ML) problem setting of sequentially allocating small subsets of training data amongst a large set of classifiers. The goal is to select a classifier that will give near-optimal accuracy when trained on all data, while also minimizing the cost of misallocated samples. This is motivated by large modern datasets and ML toolkits with many combinations of learning algorithms and hyper-parameters. Inspired by the principle of "optimism under uncertainty," we propose an innovative strategy, Data Allocation using Upper Bounds (DAUB), which robustly achieves these objectives across a variety of real-world datasets. We further develop substantial theoretical support for DAUB in an idealized setting where the expected accuracy of a classifier trained on $n$ samples can be known exactly. Under these conditions we establish a rigorous sub-linear bound on the regret of the approach (in terms of misallocated data), as well as a rigorous bound on suboptimality of the selected classifier. Our accuracy estimates using real-world datasets only entail mild violations of the theoretical scenario, suggesting that the practical behavior of DAUB is likely to approach the idealized behavior.
Ashish Sabharwal, Horst Samulowitz, Gerald Tesauro
AAAI2
2016 Adaptive data augmentation for image classification
abstract
Data augmentation is the process of generating samples by transforming training data, with the target of improving the accuracy and robustness of classifiers. In this paper, we propose a new automatic and adaptive algorithm for choosing the transformations of the samples used in data augmentation. Specifically, for each sample, our main idea is to seek a small transformation that yields maximal classification loss on the transformed sample. We employ a trust-region optimization strategy, which consists of solving a sequence of linear programs. Our data augmentation scheme is then integrated into a Stochastic Gradient Descent algorithm for training deep neural networks. We perform experiments on two datasets, and show that that the proposed scheme outperforms random data augmentation algorithms in terms of accuracy and robustness, while yielding comparable or superior results with respect to existing selective sampling approaches.
Alhussein Fawzi, Horst Samulowitz, Deepak S. Turaga, Pascal Frossard
ICIP2
2015 Towards Cognitive Automation of Data Science
abstract
A Data Scientist typically performs a number of tedious and time-consuming steps to derive insight from a raw data set. The process usually starts with data ingestion, cleaning, and transformation (e.g. outlier removal, missing value imputation), then proceeds to model building, and finally a presentation of predictions that align with the end-users objectives and preferences. It is a long, complex, and sometimes artful process requiring substantial time and effort, especially because of the combinatorial explosion in choices of algorithms (and platforms), their parameters, and their compositions. Tools that can help automate steps in this process have the potential to accelerate the time-to-delivery of useful results, expand the reach of data science to non-experts, and offer a more systematic exploration of the available options. This work presents a step towards this goal.
Alain Biem, Maria Butrico, Mark Feblowitz, Tim Klinger, Yuri Malitsky, Kenney Ng, Adam Perer, Chandra Reddy, Anton Riabov, Horst Samulowitz, Daby M. Sow, Gerald Tesauro, Deepak S. Turaga
AAAI10
2015 Model-Based Genetic Algorithms for Algorithm Configuration
Carlos Ansótegui, Yuri Malitsky, Horst Samulowitz, Meinolf Sellmann, Kevin Tierney
IJCAI3
2014 Insights into Parallelism with Intensive Knowledge Sharing
Ashish Sabharwal, Horst Samulowitz
CP2
2014 Parallel Combinatorial Optimization with Decision Diagrams
David Bergman, André Augusto Ciré, Ashish Sabharwal, Horst Samulowitz, Vijay A. Saraswat, Willem Jan van Hoeve
CPAIOR4
2013 Resolution and Parallelizability: Barriers to the Efficient Parallelization of SAT Solvers
abstract
Recent attempts to create versions of Satisfiability (SAT) solversthat exploit parallel hardware and information sharing have met withlimited success. In fact,the most successful parallel solvers in recent competitions were basedon portfolio approaches with little to no exchange of informationbetween processors. This experience contradicts the apparentparallelizability of exploring a combinatorial search space. Wepresent evidence that this discrepancy can be explained by studyingSAT solvers through a proof complexity lens, as resolution refutationengines. Starting with theobservation that a recently studied measure of resolution proofs,namely depth, provides a (weak) upper bound to the best possiblespeedup achievable by such solvers, we empirically show the existenceof bottlenecks to parallelizability that resolution proofs typicallygenerated by SAT solvers exhibit. Further, we propose a new measureof parallelizability based on the best-case makespan of an offlineresource constrained scheduling problem. This measureexplicitly accounts for a bounded number of parallel processors andappears to empirically correlate with parallel speedups observed inpractice. Our findings suggest that efficient parallelization of SATsolvers is not simply a matter of designing the right clause sharingheuristics; even in the best case, it can be --- and indeed is ---hindered by the structure of the resolution proofs current SAT solverstypically produce.
George Katsirelos, Ashish Sabharwal, Horst Samulowitz, Laurent Simon 0001
AAAI3
2013 Stronger Inference through Implied Literals from Conflicts and Knapsack Covers
Tobias Achterberg, Ashish Sabharwal, Horst Samulowitz
CPAIOR3
2013 Algorithm Portfolios Based on Cost-Sensitive Hierarchical Clustering
Yuri Malitsky, Ashish Sabharwal, Horst Samulowitz, Meinolf Sellmann
IJCAI3
2013 Snappy: A Simple Algorithm Portfolio
Horst Samulowitz, Chandra Reddy, Ashish Sabharwal, Meinolf Sellmann
SAT1
2012 Parallel SAT Solver Selection and Scheduling
Yuri Malitsky, Ashish Sabharwal, Horst Samulowitz, Meinolf Sellmann
CP3
2012 Guiding Combinatorial Optimization with UCT
Ashish Sabharwal, Horst Samulowitz, Chandra Reddy
CPAIOR2
2012 An Introduction to Search Combinators
Tom Schrijvers, Guido Tack, Pieter Wuille, Horst Samulowitz, Peter J. Stuckey
LOPSTR4
2012 SatX10: A Scalable Plug&Play Parallel SAT Framework - (Tool Presentation)
Bard Bloom, David Grove, Benjamin Herta, Ashish Sabharwal, Horst Samulowitz, Vijay A. Saraswat
SAT5
2012 Augmenting Clause Learning with Implied Literals - (Poster Presentation)
Arie Matsliah, Ashish Sabharwal, Horst Samulowitz
SAT3
2012 Learning Back-Clauses in SAT - (Poster Presentation)
Ashish Sabharwal, Horst Samulowitz, Meinolf Sellmann
SAT2
2011 Algorithm Selection and Scheduling
Serdar Kadioglu, Yuri Malitsky, Ashish Sabharwal, Horst Samulowitz, Meinolf Sellmann
CP4
2011 Search Combinators
Tom Schrijvers, Guido Tack, Pieter Wuille, Horst Samulowitz, Peter J. Stuckey
CP4
2011 Non-Model-Based Algorithm Portfolios for SAT
Yuri Malitsky, Ashish Sabharwal, Horst Samulowitz, Meinolf Sellmann
SAT3
2010 Collaborative Expert Portfolio Management
abstract
We consider the task of assigning experts from a portfolio of specialists in order to solve a set of tasks. We apply a Bayesian model which combines collaborative filtering with a feature-based description of tasks and experts to yield a general framework for managing a portfolio of experts. The model learns an embedding of tasks and problems into a latent space in which affinity is measured by the inner product. The model can be trained incrementally and can track non-stationary data, tracking potentially changing expert and task characteristics. The approach allows us to use a principled decision theoretic framework for expert selection, allowing the user to choose a utility function that best suits their objectives. The model component for taking into account the performance feedback data is pluggable, allowing flexibility. We apply the model to manage a portfolio of algorithms to solve hard combinatorial problems. This is a well studied area and we demonstrate a large improvement on the state of the art in one domain (constraint solving) and in a second domain (combinatorial auctions) created a portfolio that performed significantly better than any single algorithm.
David H. Stern, Horst Samulowitz, Ralf Herbrich, Thore Graepel, Luca Pulina, Armando Tacchella
AAAI2
2009 Experiments with Massively Parallel Constraint Solving
Lucas Bordeaux, Youssef Hamadi, Horst Samulowitz
IJCAI3
2007 Learning to Solve QBF
Horst Samulowitz, Roland Memisevic
AAAI1
2007 Dynamically Partitioning for Solving QBF
Horst Samulowitz, Fahiem Bacchus
SAT1
2006 Preprocessing QBF
Horst Samulowitz, Jessica Davies 0001, Fahiem Bacchus
CP1
2006 Binary Clause Reasoning in QBF
Horst Samulowitz, Fahiem Bacchus
SAT1
2005 Using SAT in QBF
Horst Samulowitz, Fahiem Bacchus
CP1
2001 Visualization of eclipses and planetary conjunction events. The interplay between model coherence, scaling and animation
Walter Oberschelp, Alexander Sorkine-Hornung, Horst Samulowitz
Vis. Comput.3
2000 Visualization of Eclipses and Planetary Conjunction Events: The Interplay between Model Coherence, Scaling and Animation
abstract
The problem of an instructive and realistic animation and visualization of the shadow and color-conditions during conjunctions of actively and passively illuminated cosmic objects has found only partially satisfying solutions so far. As an example we study a total solar eclipse. There are didactic shortcomings of specialized astronomical software, even though solutions have been given, which are very impressive for experts. Using the possibilities of commercial 3D animation software we present an object oriented partial solution. In order to get correct astronomical representations, we model (for different tasks) the object space under cinematic aspects with parameters for spatial and temporal scaling, for illumination and coloring under couplings of varying strength. The adaptation of the parameters to optimal acceptance of the spectator must be done a posteriori.
Walter Oberschelp, Alexander Sorkine-Hornung, Horst Samulowitz
Computer Graphics International3