@article{chirkova_hou_chirkova_amelot_2023, title={Acoustic correlates of prominence in Kala Lizu (Tibeto-Burman)}, volume={51}, ISSN={["0091-3723"]}, DOI={10.1353/jcl.2023.0008}, abstractNote={ABSTRACT:This study investigates acoustic correlates of prominence in Lizu (Tibeto-Burman). Lizu has been argued to have a hybrid prosodic system combining lexical tone on monosyllabic words and prominence patterns with stress-like and tonal characteristics on polysyllabic words, although empirical evidence is lacking. This study presents an acoustic investigation of the pitch patterns on disyllabic words in the Kala variety of Lizu (HL, HH, LH). Using the parameters of duration, intensity, and f0, it attempts to sort out different forms of prominence, and to explore their interaction with lexical tone. The measurements are taken from experimental data with eight Lizu speakers (4 male and 4 female). The acoustic results and statistical analyses suggest that the first syllable in Kala Lizu is the position of prominence in all three pitch patterns. Our results are consistent with interpreting the pitch pattern HL as more stress-like (with intensity as an acoustic correlate of stress) and the pitch patterns HH and LH as more tone-like (with stress cued by full realization of lexical tone). This study contributes to a better understanding of the prosodic organization of Kala Lizu and it also suggests methodology for further exploration of other Lizu varieties.摘要:本研究考察里汝语中韵律突显的声学相关物。里汝语曾被认为拥有一 种混合的韵律系统，结合了单音节词的声调，以及多音节词上的重音 似的和声调式的突显格局，尽管缺乏相关的实证证据。本研究对木里 县卡拉乡里汝语不同音高模式(HL、HH、LH)的双音节词进行了声学 考察，使用音长、音强和基频的参数，确定不同类型双音节词中的突 显形式，并探讨这些突显与词层面声调之间的相互关系。测量数据来 自 8 位里汝语母语者(4 男 4 女)的语音实验。声学结果和统计分析表 明，卡拉乡里汝语的全部三种音高模式中，第一个音节都处于突显位置，HL 类型的音高模式表现得更像重音(以音强为重音的声学相关物)， HH 和 LH 类型的音高模式表现得更像声调(以词调的完整实现来体现 重音)。这项研究有助于更好地理解里汝语的韵律结构，并为进一步探 索其他里汝语土语提供了方法。}, number={1}, journal={JOURNAL OF CHINESE LINGUISTICS}, author={Chirkova, Katia and Hou, Pei -Yu and Chirkova, Rada and Amelot, Angelique}, year={2023}, month={Jan}, pages={101–146} }
 @article{ao_cheng_chirkova_kolaitis_2023, title={Theory and Practice of Relational-to-RDF Temporal Data Exchange and Query Answering}, volume={15}, ISSN={["1936-1955"]}, DOI={10.1145/3591359}, abstractNote={We consider the problem of answering temporal queries on RDF stores, in presence of atemporal RDFS domain ontologies, of relational data sources that include temporal information, and of rules that map the domain information in the source schemas into the target ontology. Our proposed practice-oriented solution consists of two rule-based domain-independent algorithms. The first algorithm materializes target RDF data via a version of data exchange that enriches both the data and the ontology with temporal information from the relational sources. The second algorithm accepts as inputs temporal queries expressed in terms of the domain ontology using a lightweight temporal extension of SPARQL, and ensures successful evaluation of the queries on the materialized temporally-enriched RDF data. To study the quality of the information generated by the algorithms, we develop a general framework that formalizes the relational-to-RDF temporal data-exchange problem. The framework includes a chase formalism and a formal solution for the problem of answering temporal queries in the context of relational-to-RDF temporal data exchange. In this article, we present the algorithms and the formal framework that proves correctness of the information output by the algorithms, and also report on the algorithm implementation and experimental results for two application domains.}, number={2}, journal={ACM JOURNAL OF DATA AND INFORMATION QUALITY}, author={Ao, Jing and Cheng, Zehui and Chirkova, Rada and Kolaitis, Phokion G.}, year={2023}, month={Jun} }
 @article{hou_korn_melo-filho_wright_tropsha_chirkova_2022, title={Compact Walks: Taming Knowledge-Graph Embeddings With Domain- and Task-Specific Pathways}, ISSN={["0730-8078"]}, DOI={10.1145/3514221.3517903}, abstractNote={Knowledge-graph (KG) embeddings have emerged as a promise in addressing challenges faced by modern biomedical research, including the growing gap between therapeutic needs and available treatments. The popularity of KG embeddings in graph analytics is on the rise, due at least partially to the presumed semanticity of the learned embeddings. Unfortunately, the ability of a node neighborhood picked up by an embedding to capture the node's semantics may depend on the characteristics of the data. One of the reasons for this problem is that KG nodes can be promiscuous, that is, associated with a number of different relationships that are not unique or indicative of the properties of the nodes. To address the promiscuity challenge and the documented runtime-performance challenge in real-life KG embedding tools, we propose to use domain- and task-specific information to specify regular-expression pathways that define neighborhoods of KG nodes of interest. Our proposed CompactWalks framework uses these semantic subgraphs to enable meaningful compact walks in random-walk based KG embedding methods. We report the results of case studies for the task of determining which pharmaceutical drugs could treat the same diseases. The findings suggest that our CompactWalks approach has the potential to address the promiscuity and runtime-performance challenges in applying embedding tools to large-scale KGs in real life, in the biomedical domain and possibly beyond.}, journal={PROCEEDINGS OF THE 2022 INTERNATIONAL CONFERENCE ON MANAGEMENT OF DATA (SIGMOD '22)}, author={Hou, Pei-Yu and Korn, Daniel R. and Melo-Filho, Cleber C. and Wright, David R. and Tropsha, Alexander and Chirkova, Rada}, year={2022}, pages={458–469} }
 @misc{korn_thieme_alves_yeakey_borba_capuzzi_fecho_bizon_edwards_chirkova_et al._2022, title={Defining clinical outcome pathways}, volume={27}, ISSN={["1878-5832"]}, DOI={10.1016/j.drudis.2022.02.008}, abstractNote={Here, we propose a broad concept of 'Clinical Outcome Pathways' (COPs), which are defined as a series of key molecular and cellular events that underlie therapeutic effects of drug molecules. We formalize COPs as a chain of the following events: molecular initiating event (MIE) → intermediate event(s) → clinical outcome. We illustrate the concept with COP examples both for primary and alternative (i.e., drug repurposing) therapeutic applications. We also describe the elucidation of COPs for several drugs of interest using the publicly accessible Reasoning Over Biomedical Objects linked in Knowledge-Oriented Pathways (ROBOKOP) biomedical knowledge graph-mining tool. We propose that broader use of COP uncovered with the help of biomedical knowledge graph mining will likely accelerate drug discovery and repurposing efforts.}, number={6}, journal={DRUG DISCOVERY TODAY}, author={Korn, Daniel and Thieme, Andrew J. and Alves, Vinicius M. and Yeakey, Michael and Borba, Joyce V. V. B. and Capuzzi, Stephen J. and Fecho, Karamarie and Bizon, Chris and Edwards, Stephen W. and Chirkova, Rada and et al.}, year={2022}, month={Jun}, pages={1671–1678} }
 @misc{alves_korn_pervitsky_thieme_capuzzi_baker_chirkova_ekins_muratov_hickey_et al._2022, title={Knowledge-based approaches to drug discovery for rare diseases}, volume={27}, ISSN={["1878-5832"]}, DOI={10.1016/j.drudis.2021.10.014}, abstractNote={The conventional drug discovery pipeline has proven to be unsustainable for rare diseases. Herein, we discuss recent advances in biomedical knowledge mining applied to discovering therapeutics for rare diseases. We summarize current chemogenomics data of relevance to rare diseases and provide a perspective on the effectiveness of machine learning (ML) and biomedical knowledge graph mining in rare disease drug discovery. We illustrate the power of these methodologies using a chordoma case study. We expect that a broader application of knowledge graph mining and artificial intelligence (AI) approaches will expedite the discovery of viable drug candidates against both rare and common diseases.}, number={2}, journal={DRUG DISCOVERY TODAY}, author={Alves, Vinicius M. and Korn, Daniel and Pervitsky, Vera and Thieme, Andrew and Capuzzi, Stephen J. and Baker, Nancy and Chirkova, Rada and Ekins, Sean and Muratov, Eugene N. and Hickey, Anthony and et al.}, year={2022}, month={Feb}, pages={490–502} }
 @article{korn_pervitsky_bobrowski_alves_schmitt_bizon_baker_chirkova_cherkasov_muratov_et al._2021, title={COVID-19 Knowledge Extractor (COKE): A Curated Repository of Drug-Target Associations Extracted from the CORD-19 Corpus of Scientific Publications on COVID-19}, volume={61}, ISSN={["1549-960X"]}, DOI={10.1021/acs.jcim.1c01285}, abstractNote={The COVID-19 pandemic has catalyzed a widespread effort to identify drug candidates and biological targets of relevance to SARS-COV-2 infection, which resulted in large numbers of publications on this subject. We have built the COVID-19 Knowledge Extractor (COKE), a web application to extract, curate, and annotate essential drug–target relationships from the research literature on COVID-19. SciBiteAI ontological tagging of the COVID Open Research Data set (CORD-19), a repository of COVID-19 scientific publications, was employed to identify drug–target relationships. Entity identifiers were resolved through lookup routines using UniProt and DrugBank. A custom algorithm was used to identify co-occurrences of the target protein and drug terms, and confidence scores were calculated for each entity pair. COKE processing of the current CORD-19 database identified about 3000 drug–protein pairs, including 29 unique proteins and 500 investigational, experimental, and approved drugs. Some of these drugs are presently undergoing clinical trials for COVID-19. The COKE repository and web application can serve as a useful resource for drug repurposing against SARS-CoV-2. COKE is freely available at https://coke.mml.unc.edu/, and the code is available at https://github.com/DnlRKorn/CoKE.}, number={12}, journal={JOURNAL OF CHEMICAL INFORMATION AND MODELING}, author={Korn, Daniel and Pervitsky, Vera and Bobrowski, Tesia and Alves, Vinicius M. and Schmitt, Charles and Bizon, Chris and Baker, Nancy and Chirkova, Rada and Cherkasov, Artem and Muratov, Eugene and et al.}, year={2021}, month={Dec}, pages={5734–5741} }
 @article{korn_bobrowski_li_kebede_wang_owen_vaidya_muratov_chirkova_bizon_et al._2021, title={COVID-KOP: integrating emerging COVID-19 data with the ROBOKOP database}, volume={37}, ISSN={["1460-2059"]}, DOI={10.1093/bioinformatics/btaa718}, abstractNote={Abstract Summary In response to the COVID-19 pandemic, we established COVID-KOP, a new knowledgebase integrating the existing Reasoning Over Biomedical Objects linked in Knowledge Oriented Pathways (ROBOKOP) biomedical knowledge graph with information from recent biomedical literature on COVID-19 annotated in the CORD-19 collection. COVID-KOP can be used effectively to generate new hypotheses concerning repurposing of known drugs and clinical drug candidates against COVID-19 by establishing respective confirmatory pathways of drug action. Availability and implementation COVID-KOP is freely accessible at https://covidkop.renci.org/. For code and instructions for the original ROBOKOP, see: https://github.com/NCATS-Gamma/robokop.}, number={4}, journal={BIOINFORMATICS}, author={Korn, Daniel and Bobrowski, Tesia and Li, Michael and Kebede, Yaphet and Wang, Patrick and Owen, Phillips and Vaidya, Gaurav and Muratov, Eugene and Chirkova, Rada and Bizon, Chris and et al.}, year={2021}, month={Feb}, pages={586–587} }
 @article{chirkova_doyle_reutter_2021, title={Ensuring Data Readiness for Quality Requirements with Help from Procedure Reuse}, volume={13}, ISSN={["1936-1955"]}, DOI={10.1145/3428154}, abstractNote={Assessing and improving the quality of data are fundamental challenges in Big-Data applications. These challenges have given rise to numerous solutions targeting transformation, integration, and cl...}, number={3}, journal={ACM JOURNAL OF DATA AND INFORMATION QUALITY}, author={Chirkova, Rada and Doyle, Jon and Reutter, Juan}, year={2021}, month={Sep} }
 @article{schatz_melo-filho_tropsha_chirkova_2021, title={Explaining Drug-Discovery Hypotheses Using Knowledge-Graph Patterns}, ISSN={["2639-1589"]}, DOI={10.1109/BigData52589.2021.9672006}, abstractNote={Drug discovery is an important process used by biomedical experts to identify potential treatments for diseases. In its traditional form, the process requires significant expert time and manual effort. By encoding a wealth of information about relationships between drugs and diseases, modern large-scale biomedical knowledge graphs provide excellent opportunities to accelerate drug discovery, by automating aspects of the process. One opportunity is to use explainable fact-checking tools to generate explanations for hypothesized drug-disease treatment relationships in a given knowledge graph, with a reliability score assigned to each explanation. The explanations and their scores can then be used by experts to determine which drug-disease pairs to consider for clinical trials.In our collaboration with a biomedical team, we have found that existing explainable fact-checking tools are not necessarily helpful in drug discovery, as their explanation formats and evaluation metrics do not match well the requirements of scientific discovery in the biomedical domain. To address these challenges in using fact-checking tools in drug discovery, we introduce a scalable automated approach for generating explanations that are modeled after existing biomedical concepts and supplemented with data-supported evaluation metrics. Our explanations are based on knowledge-graph patterns, which are readily understood by biomedical experts. Our experimental results suggest that our proposed metrics are accurate and useful on largescale biomedical knowledge graphs, and our explanations are understandable and reasonable to experts doing drug discovery.}, journal={2021 IEEE INTERNATIONAL CONFERENCE ON BIG DATA (BIG DATA)}, author={Schatz, Kara and Melo-Filho, Cleber and Tropsha, Alexander and Chirkova, Rada}, year={2021}, pages={3709–3716} }
 @article{moon_jin_dong_abrar_zheng_chirkova_tropsha_2021, title={Original Learning Drug-Disease-Target Embedding (DDTE) from knowledge graphs to inform drug repurposing hypotheses}, volume={119}, ISSN={["1532-0480"]}, DOI={10.1016/j.jbi.2021.103838}, abstractNote={We aimed to develop and validate a new graph embedding algorithm for embedding drug-disease-target networks to generate novel drug repurposing hypotheses. Our model denotes drugs, diseases and targets as subjects, predicates and objects, respectively. Each entity is represented by a multidimensional vector and the predicate is regarded as a translation vector from a subject to an object vectors. These vectors are optimized so that when a subject-predicate-object triple represents a known drug-disease-target relationship, the summed vector between the subject and the predicate is to be close to that of the object; otherwise, the summed vector is distant from the object. The DTINet dataset was utilized to test this algorithm and discover unknown links between drugs and diseases. In cross-validation experiments, this new algorithm outperformed the original DTINet model. The MRR (Mean Reciprocal Rank) values of our models were around 0.80 while those of the original model were about 0.70. In addition, we have identified and verified several pairs of new therapeutic relations as well as adverse effect relations that were not recorded in the original DTINet dataset. This approach showed excellent performance, and the predicted drug-disease and drug-side-effect relationships were found to be consistent with literature reports. This novel method can be used to analyze diverse types of emerging biomedical and healthcare-related knowledge graphs (KG).}, journal={JOURNAL OF BIOMEDICAL INFORMATICS}, author={Moon, Changsung and Jin, Chunming and Dong, Xialan and Abrar, Saad and Zheng, Weifan and Chirkova, Rada Y. and Tropsha, Alexander}, year={2021}, month={Jul} }
 @article{ao_dinakaran_yang_wright_chirkova_2021, title={Trustworthy Knowledge Graph Population From Texts for Domain Query Answering}, ISSN={["2639-1589"]}, DOI={10.1109/BigData52589.2021.9671514}, abstractNote={Obtaining answers to domain-specific questions over large-scale unstructured (text) data is an important component of data analytics in many application domains. As manual question answering does not scale to large text corpora, it is common to use information extraction (IE) to preprocess the texts of interest prior to posing the questions. This is often done by transforming text corpora into the knowledge-graph (KG) triple format that is suitable for efficient processing of the user questions in graph-oriented data-intensive systems.In a number of real-life scenarios, trustworthiness of the answers obtained from domain-specific texts is vital for downstream decision making. In this paper we focus on one critical aspect of trustworthiness, which concerns aligning with the given domain vocabularies (ontologies) those KG triples that are obtained from the source texts via IE solutions. To address this problem, we introduce a scalable domain-independent text-to-KG approach that adapts to specific domains by using domain ontologies, without having to consult external triple repositories. Our IE solution builds on the power of neural-based learning models and leverages feature engineering to distinguish ontology-aligned data from generic data in the source texts. Our experimental results indicate that the proposed approach could be more dependable than a state-of-the-art IE baseline in constructing KGs that are suitable for trustworthy domain question answering on text data.}, journal={2021 IEEE INTERNATIONAL CONFERENCE ON BIG DATA (BIG DATA)}, author={Ao, Jing and Dinakaran, Swathi and Yang, Hungjian and Wright, David and Chirkova, Rada}, year={2021}, pages={4590–4599} }
 @book{afrati_chirkova_2019, place={San Rafael, CA}, title={Answering queries using views}, ISBN={1681734648 9781681734644 1681734621 9781681734620}, publisher={Morgan & Claypool Publishers}, author={Afrati, Foto and Chirkova, Rada}, year={2019} }
 @article{jiang_chirkova_doyle_rosenthal_2018, title={Poster: Towards Greater Expressiveness, Flexibility, and Uniformity in Access Control}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85049303993&partnerID=MN8TOARS}, DOI={10.1145/3205977.3208950}, abstractNote={Attribute-based access control (ABAC) is a general access control model that subsumes numerous earlier access control models. Its increasing popularity stems from the intuitive generic structure of granting permissions based on application and domain attributes of users, subjects, objects, and other entities in the system. Multiple formal and informal languages have been developed to express policies in terms of such attributes. The utility of ABAC policy languages is potentially undermined without a properly formalized underlying model. The high-level structure in a majority of ABAC models consists of sets of tokens and sets of sets, expressions that demand that the reader unpack multiple levels of sets and tokens to determine what things mean. The resulting reduced readability potentially endangers correct expression, reduces maintainability, and impedes validation. These problems could be magnified in models that employ nonuniform representations of actions and their governing policies. We propose to avoid these magnified problems by recasting the high-level structure of ABAC models in a logical formalism that treats all actions (by users and others) uniformly and that keeps existing policy languages in place by interpreting their attributes in terms of the restructured model. In comparison to existing ABAC models, use of a logical language for model formalization, including hierarchies of types of entities and attributes, promises improved expressiveness in specifying the relationships between and requirements on application and domain attributes. A logical modeling language also potentially improves flexibility in representing relationships as attributes to support some widely used policy languages. Consistency and intelligibility are improved by using uniform means for representing different types of controlled actions---such as regular access control actions, administrative actions, and user logins---and their governing policies. Logical languages also provide a well-defined denotational semantics supported by numerous formal inference and verification tools.}, journal={SACMAT'18: PROCEEDINGS OF THE 23RD ACM SYMPOSIUM ON ACCESS CONTROL MODELS & TECHNOLOGIES}, author={Jiang, Jiaming and Chirkova, Rada and Doyle, Jon and Rosenthal, Arnon}, year={2018}, pages={217–219} }
 @inbook{chen_yu_chirkova_2017, title={Differentially Private K-Skyband Query Answering Through Adaptive Spatial Decomposition}, ISBN={9783319611754 9783319611761}, ISSN={0302-9743 1611-3349}, url={http://dx.doi.org/10.1007/978-3-319-61176-1_8}, DOI={10.1007/978-3-319-61176-1_8}, abstractNote={Given a set of multi-dimensional points, a $$k$$ -skyband query retrieves those points dominated by no more than k other points. $$k$$ -skyband queries are an important type of multi-criteria analysis with diverse applications in practice. In this paper, we investigate techniques to answer $$k$$ -skyband queries with differential privacy. We first propose a general technique BBS-Priv, which accepts any differentially private spatial decomposition tree as input and leverages data synthesis to answer $$k$$ -skyband queries privately. We then show that, though quite a few private spatial decomposition trees are proposed in the literature, they are mainly designed to answer spatial range queries. Directly integrating them with BBS-Priv would introduce too much noise to generate useful $$k$$ -skyband results. To address this problem, we propose a novel spatial decomposition technique k-skyband tree specially optimized for k-skyband queries, which partitions data adaptively based on the parameter k. We further propose techniques to generate a k-skyband tree over spatial data that satisfies differential privacy, and combine BBS-Priv with the private k-skyband tree to answer $$k$$ -skyband queries. We conduct extensive experiments based on two real-world datasets and three synthetic datasets that are commonly used for evaluating $$k$$ -skyband queries. The results show that the proposed scheme significantly outperforms existing differentially private spatial decomposition schemes and achieves high utility when privacy budgets are properly allocated.}, booktitle={Data and Applications Security and Privacy XXXI}, publisher={Springer International Publishing}, author={Chen, Ling and Yu, Ting and Chirkova, Rada}, year={2017}, pages={142–163} }
 @inproceedings{tan_chirkova_gadepally_mattson_2017, title={Enabling query processing across heterogeneous data models: A survey}, DOI={10.1109/bigdata.2017.8258302}, abstractNote={Modern applications often need to manage and analyze widely diverse datasets that span multiple data models [1], [2], [3], [4], [5]. Warehousing the data through Extract-Transform-Load (ETL) processes can be expensive in such scenarios. Transforming disparate data into a single data model may degrade performance. Further, curating diverse datasets and maintaining the pipeline can prove to be labor intensive. As a result, an emerging trend is to shift the focus to federating specialized data stores and enabling query processing across heterogeneous data models [6]. This shift can bring many advantages: First, systems can natively leverage multiple data models, which can translate to maximizing the semantic expressiveness of underlying interfaces and leveraging the internal processing capabilities of component data stores. Second, federated architectures support query-specific data integration with just-in-time transformation and migration, which has the potential to significantly reduce the operational complexity and overhead. Projects that focus on developing systems in this research area stem from various backgrounds and address diverse concerns, which could make it difficult to form a consistent view of the work in this area. In this survey, we introduce a taxonomy for describing the state of the art and propose a systematic evaluation framework conducive to understanding of query-processing characteristics in the relevant systems. We use the framework to assess four representative implementations: BigDAWG [7], [8], CloudMdsQL [9], [10], Myria [11], [12], and Apache Drill [13].}, booktitle={2017 IEEE International Conference on Big Data (Big Data)}, author={Tan, R. and Chirkova, R. and Gadepally, V. and Mattson, T. G.}, year={2017}, pages={3211–3220} }
 @article{chirkova_yu_2017, title={Exact Detection of Information Leakage: Decidability and Complexity}, volume={10420}, ISBN={["978-3-662-55607-8"]}, ISSN={["1611-3349"]}, DOI={10.1007/978-3-662-55608-5_1}, abstractNote={Elaborate security policies often require organizations to restrict user data access in a fine-grained manner, instead of traditional table- or column-level access control. Not surprisingly, managing fine-grained access control in software is rather challenging. In particular, if access is not configured carefully, information leakage may happen: Users may infer sensitive information through the data explicitly accessible to them. In this paper we formalize this information-leakage problem, by modeling sensitive information as answers to “secret queries,” and by modeling access-control rules as views. We focus on the scenario where sensitive information can be deterministically derived by adversaries. We review a natural data-exchange based inference model for detecting information leakage, and show its capabilities and limitation. We then introduce and formally study a new inference model, view-verified data exchange, that overcomes the limitation for the query language under consideration. Our formal study provides correctness and complexity results for the proposed inference model in the context of queries belonging to a frequent realistic query type and common types of integrity constraints on the data.}, journal={TRANSACTIONS ON LARGE-SCALE DATA- AND KNOWLEDGE-CENTERED SYSTEMS XXXII}, author={Chirkova, Rada and Yu, Ting}, year={2017}, pages={1–23} }
 @article{chirkova_2016, title={Combined-semantics equivalence of conjunctive queries: Decidability and tractability results}, volume={82}, ISSN={0022-0000}, url={http://dx.doi.org/10.1016/J.JCSS.2015.11.001}, DOI={10.1016/J.JCSS.2015.11.001}, abstractNote={Query containment and equivalence are fundamental problems in the context of query processing and optimization. In this paper, we consider combined-semantics equivalence of conjunctive (CQ) queries. The combined-semantics formalism [10], [11] generalizes the well-known and practically useful notions of set, bag, and bag-set semantics for CQ queries. It also provides tools for studying practical SQL queries, specifically important types of queries arising in on-line analytical processing. In our study, we introduce a containment-based algorithm for deciding combined-semantics equivalence for pairs of CQ queries that belong to a large well-behaved class of “explicit-wave” queries. Our algorithm, as well as our general sufficient condition for containment of combined-semantics CQ queries, generalizes in a uniform way the tests reported in [3], [6], [11]. Moreover, we single out a subclass of explicit-wave CQ queries for which it is tractable to determine combined-semantics equivalence.}, number={3}, journal={Journal of Computer and System Sciences}, publisher={Elsevier BV}, author={Chirkova, Rada}, year={2016}, month={May}, pages={395–465} }
 @inbook{harenberg_seay_bello_chirkova_doraiswamy_samatova_2016, title={Knowledge-Guided Maximal Clique Enumeration}, ISBN={9783319495859 9783319495866}, ISSN={0302-9743 1611-3349}, url={http://dx.doi.org/10.1007/978-3-319-49586-6_43}, DOI={10.1007/978-3-319-49586-6_43}, abstractNote={Maximal clique enumeration is a long-standing problem in graph mining and knowledge discovery. Numerous classic algorithms exist for solving this problem. However, these algorithms focus on enumerating all maximal cliques, which may be computationally impractical and much of the output may be irrelevant to the user. To address this issue, we introduce the problem of knowledge-biased clique enumeration, a query-driven formulation that reduces output space, computation time, and memory usage. Moreover, we introduce a dynamic state space indexing strategy for efficiently processing multiple queries over the same graph. This strategy reduces redundant computations by dynamically indexing the constituent state space generated with each query. Experimental results over real-world networks demonstrate this strategy’s effectiveness at reducing the cumulative query-response time. Although developed in the context of maximal cliques, our techniques could possibly be generalized to other constraint-based graph enumeration tasks.}, booktitle={Advanced Data Mining and Applications}, publisher={Springer International Publishing}, author={Harenberg, Steve and Seay, Ramona G. and Bello, Gonzalo A. and Chirkova, Rada Y. and Doraiswamy, P. Murali and Samatova, Nagiza F.}, year={2016}, pages={604–618} }
 @article{chen_yu_chirkova_2016, title={Privacy-Preserving Two-Party Skyline Queries Over Horizontally Partitioned Data}, volume={9895}, ISBN={["978-3-319-45930-1"]}, ISSN={["1611-3349"]}, DOI={10.1007/978-3-319-45931-8_12}, abstractNote={Skyline queries are an important type of multi-criteria analysis with diverse applications in practice (e.g., personalized services and intelligent transport systems). In this paper, we study how to answer skyline queries efficiently and in a privacy-preserving way when the data are sensitive and distributedly owned by multiple parties. We adopt the classical honest-but-curious attack model, and design a suite of efficient protocols for skyline queries over horizontally partitioned data. We analyze in detail the efficiency of each of the proposed protocols as well as their privacy guarantees.}, journal={INFORMATION SECURITY THEORY AND PRACTICE, WISTP 2016}, author={Chen, Ling and Yu, Ting and Chirkova, Rada}, year={2016}, pages={187–203} }
 @inproceedings{lauren_pigg_2016, title={Toward entrepreneurial pedagogies: rethinking professional networking as knowledge making}, DOI={10.1109/ipcc.2016.7740535}, abstractNote={This paper offers initial suggestions for teaching professional social networking as a technical communication practice. Our guidelines build from recent qualitative research analyzing the networking relationships, practices, and technologies that support technical communication entrepreneurship. This research demonstrated how technical communication entrepreneurs perceive networking to be steeped in learning and sharing knowledge across professional and personal social fields. Based on what was learned from participants, we offer a model for and guidelines toward teaching networking as connected to knowledge sharing and building. This paper next offers an example assignment sequence from a master's level technical communication course focused on online information design. Through research and theory building, we suggest that instructors and students should understand professional social networking as a multilayered practice of learning and sharing collective knowledge.}, booktitle={2016 ieee international professional communication conference (ipcc)}, author={Lauren, B. and Pigg, S.}, year={2016} }
 @inbook{alborzi_chirkova_doyle_fathi_2015, title={Determining Query Readiness for Structured Data}, volume={9263}, ISBN={9783319227283 9783319227290}, ISSN={0302-9743 1611-3349}, url={http://dx.doi.org/10.1007/978-3-319-22729-0_1}, DOI={10.1007/978-3-319-22729-0_1}, abstractNote={The outcomes and quality of organizational decisions depend on the characteristics of the data available for making the decisions and on the value of the data in the decision-making process. Toward enabling management of these aspects of data in analytics, we introduce and investigate Data Readiness Level (DRL), a quantitative measure of the value of a piece of data at a given point in a processing flow. Our DRL proposal is a multidimensional measure that takes into account the relevance, completeness, and utility of data with respect to a given analysis task. This study provides a formalization of DRL in a structured-data scenario, and illustrates how knowledge of rules and facts, both within and outside the given data, can be used to identify those transformations of the data that improve its DRL.}, booktitle={Big Data Analytics and Knowledge Discovery}, publisher={Springer International Publishing}, author={Alborzi, Farid and Chirkova, Rada and Doyle, Jon and Fathi, Yahya}, year={2015}, pages={3–14} }
 @inproceedings{alborzi_chirkova_doyle_fathi_2015, title={Determining query readiness for structured data}, volume={9263}, booktitle={Big data analytics and knowledge discovery}, author={Alborzi, F. and Chirkova, R. and Doyle, J. and Fathi, Y.}, year={2015}, pages={3–14} }
 @article{alborzi_chirkova_yu_2015, title={Exact Detection of Information Leakage in Database Access Control}, volume={9263}, ISBN={["978-3-319-22728-3"]}, ISSN={["1611-3349"]}, DOI={10.1007/978-3-319-22729-0_31}, abstractNote={Elaborate security policies often require organizations to restrict user data access in a fine-grained manner, instead of traditional table- or column-level access control. Not surprisingly, managing fine-grained access control in software is rather challenging. In particular, if access is not configured carefully, information leakage may happen: Users may infer sensitive information through the data explicitly accessible to them in centralized systems or in the cloud. In this paper we formalize this information-leakage problem, by modeling sensitive information as answers to “secret queries,” and by modeling access-control rules as views. We focus on the scenario where sensitive information can be deterministically derived by adversaries. We review a natural data-exchange based inference model for detecting information leakage, and show its capabilities and limitation. We then introduce and formally study a new inference model, view-verified data exchange, that overcomes the limitation for the query language under consideration.}, journal={BIG DATA ANALYTICS AND KNOWLEDGE DISCOVERY}, author={Alborzi, Farid and Chirkova, Rada and Yu, Ting}, year={2015}, pages={403–415} }
 @article{chirkova_2014, title={Combined-Semantics Equivalence and Minimization of Conjunctive Queries}, volume={57}, ISSN={["1460-2067"]}, DOI={10.1093/comjnl/bxt032}, number={5}, journal={COMPUTER JOURNAL}, author={Chirkova, Rada}, year={2014}, month={May}, pages={775–795} }
 @article{asgharzadeh talebi_chirkova_fathi_2013, title={An integer programming approach for the view and index selection problem}, volume={83}, ISSN={0169-023X}, url={http://dx.doi.org/10.1016/j.datak.2012.11.001}, DOI={10.1016/j.datak.2012.11.001}, abstractNote={The view- and index-selection problem is a combinatorial optimization problem that arises in the context of on-line analytical processing (OLAP) in database-management systems. We propose an integer programming (IP) model for this problem and study the properties of the views and indexes that appear in the optimal solution for this model. We then use these properties to remove a number of variables and constraints from the corresponding IP model and obtain a model that is significantly smaller, yet its optimal solution is guaranteed to be optimal for the original problem. This allows us to solve realistic-size instances of the problem in reasonable time using commercial IP solvers. Subsequently, we propose heuristic strategies to further reduce the size of this IP model and dramatically reduce its execution time, although we no longer guarantee that the reduced IP model offers a globally optimal solution for the original problem. Finally, we carry out an extensive computational study to evaluate the effectiveness of these IP models for solving the OLAP view- and index-selection problem.}, journal={Data & Knowledge Engineering}, publisher={Elsevier BV}, author={Asgharzadeh Talebi, Zohreh and Chirkova, Rada and Fathi, Yahya}, year={2013}, month={Jan}, pages={111–125} }
 @article{chen_chirkova_sadri_salo_2013, title={Query optimization in information integration}, volume={50}, ISSN={0001-5903 1432-0525}, url={http://dx.doi.org/10.1007/S00236-013-0179-1}, DOI={10.1007/S00236-013-0179-1}, number={4}, journal={Acta Informatica}, publisher={Springer Science and Business Media LLC}, author={Chen, Dongfeng and Chirkova, Rada and Sadri, Fereidoon and Salo, Tiia J.}, year={2013}, month={Apr}, pages={257–287} }
 @inbook{huang_chirkova_fathi_2013, title={Two-Stage Stochastic View Selection for Data-Analysis Queries}, ISBN={9783642327407 9783642327414}, ISSN={2194-5357 2194-5365}, url={http://dx.doi.org/10.1007/978-3-642-32741-4_11}, DOI={10.1007/978-3-642-32741-4_11}, abstractNote={We consider the problem of selecting an optimal set of views to answer a given collection of queries at the present time (stage 1) as well as several collections of queries in the future (stage 2), with a given probability of occurrence associated with each collection, so as to minimize the expected value of the corresponding query response time, while keeping the total size of the views within a given limit. We formulate this problem as a two-stage stochastic programming problem. We show that this model is equivalent to an integer programming (IP) model that can be solved via various commercial IP solvers. We also study the relationship between the queries and the views in this context and use this relationship to reduce the size of the corresponding IP model, hence increase the scalability of our proposed approach.}, booktitle={Advances in Intelligent Systems and Computing}, publisher={Springer Berlin Heidelberg}, author={Huang, Rong and Chirkova, Rada and Fathi, Yahya}, year={2013}, pages={115–123} }
 @inbook{huang_chirkova_fathi_2012, title={Deterministic View Selection for Data-Analysis Queries: Properties and Algorithms}, ISBN={9783642330735 9783642330742}, ISSN={0302-9743 1611-3349}, url={http://dx.doi.org/10.1007/978-3-642-33074-2_15}, DOI={10.1007/978-3-642-33074-2_15}, abstractNote={The view-selection problem is a combinatorial optimization problem that arises in the context of on-line analytical processing (OLAP) in database management systems. We pose the problem as an integer programming (IP) model, study its structural properties, and propose effective techniques for reducing the search space of views and thus the size of the corresponding IP model. We then use these results to design both exact methods and heuristic algorithms that are effective for solving relatively large realistic-size instances of the problem.}, booktitle={Advances in Databases and Information Systems}, publisher={Springer Berlin Heidelberg}, author={Huang, Rong and Chirkova, Rada and Fathi, Yahya}, year={2012}, pages={195–208} }
 @book{chirkova_yang_2012, title={Materialized views}, publisher={Boston, [Massachusetts]: now Pub.}, author={Chirkova, R. and Yang, J.}, year={2012} }
 @article{chirkova_libkin_reutter_2012, title={Tractable XML data exchange via relations}, volume={6}, ISSN={["2095-2236"]}, DOI={10.1007/s11704-012-2023-0}, abstractNote={We consider data exchange for XML documents: given source and target schemas, a mapping between them, and a document conforming to the source schema, construct a target document and answer target queries in a way that is consistent with the source information. The problem has primarily been studied in the relational context, in which data-exchange systems have also been built. Since many XML documents are stored in relations, it is natural to consider using a relational system for XML data exchange. However, there is a complexity mismatch between query answering in relational and in XML data exchange. This indicates that to make the use of relational systems possible, restrictions have to be imposed on XML schemas and mappings, as well as on XML shredding schemes. We isolate a set of five requirements that must be fulfilled in order to have a faithful representation of the XML data-exchange problem by a relational translation. We then demonstrate that these requirements naturally suggest the in-lining technique for data-exchange tasks. Our key contribution is to provide shredding algorithms for schemas, documents, mappings and queries, and demonstrate that they enable us to correctly perform XML data-exchange tasks using a relational system.}, number={3}, journal={FRONTIERS OF COMPUTER SCIENCE}, author={Chirkova, Rada and Libkin, Leonid and Reutter, Juan L.}, year={2012}, month={Jun}, pages={243–263} }
 @article{afrati_chirkova_2011, title={Selecting and using views to compute aggregate queries}, volume={77}, DOI={10.1016/j.jcss.2010.10.003}, abstractNote={We consider a workload of aggregate queries and investigate the problem of selecting materialized views that (1) provide equivalent rewritings for all the queries, and (2) are optimal, in that the cost of evaluating the query workload is minimized. We consider conjunctive views and rewritings, with or without aggregation; in each rewriting, only one view contributes to computing the aggregated query output. We look at query rewriting using existing views and at view selection. In the query-rewriting problem, we give sufficient and necessary conditions for a rewriting to exist. For view selection, we prove complexity results. Finally, we give algorithms for obtaining rewritings and selecting views.}, number={6}, journal={Journal of Computer and System Sciences}, author={Afrati, F. and Chirkova, R.}, year={2011}, pages={1079–1107} }
 @inbook{afrati_chandrachud_chirkova_mitra_2009, title={Approximate Rewriting of Queries Using Views}, ISBN={9783642039720 9783642039737}, ISSN={0302-9743 1611-3349}, url={http://dx.doi.org/10.1007/978-3-642-03973-7_13}, DOI={10.1007/978-3-642-03973-7_13}, abstractNote={We study approximate, that is contained and containing, rewritings of queries using views. We consider conjunctive queries with arithmetic comparisons (CQACs), which capture the full expressive power of SQL select-project-join queries. For contained rewritings, we present a sound and complete algorithm for constructing, for CQAC queries and views, a maximally-contained rewriting (MCR) whose all CQAC disjuncts have up to a predetermined number of view literals. For containing rewritings, we present a sound and efficient algorithm pruned-MiCR, which computes a CQAC containing rewriting that does not contain any other CQAC containing rewriting (i.e., computes a minimally containing rewriting, MiCR) and that has the minimum possible number of relational subgoals. As a result, the MiCR rewriting produced by our algorithm may be very efficient to execute. Both algorithms have good scalability and perform well in many practical cases, due to their extensive pruning of the search space, see [1].}, booktitle={Advances in Databases and Information Systems}, publisher={Springer Berlin Heidelberg}, author={Afrati, Foto and Chandrachud, Manik and Chirkova, Rada and Mitra, Prasenjit}, year={2009}, pages={164–178} }
 @article{chen_chirkova_sadri_2009, title={Query optimization using restructured views: Theory and experiments}, volume={34}, ISSN={["1873-6076"]}, DOI={10.1016/j.is.2008.10.002}, abstractNote={We study optimization of relational queries using materialized views, where views may be regular or restructured. In a restructured view, some data from the base table(s) are represented as metadata-that is, schema information, such as table and attribute names-or vice versa. Using restructured views in query optimization opens up a new spectrum of views that were not previously available, and can result in significant additional savings in query-evaluation costs. These savings can be obtained due to a significantly larger set of views to choose from, and may involve reduced table sizes, elimination of self-joins, clustering produced by restructuring, and horizontal partitioning. In this paper we propose a general query-optimization framework that treats regular and restructured views in a uniform manner and is applicable to SQL select-project-join queries and views without or with aggregation. Within the framework we provide (1) algorithms to determine when a view (regular or restructured) is usable in answering a query and (2) algorithms to rewrite queries using usable views. Semantic information, such as knowledge of the key of a view, can be used to further optimize a rewritten query. Within our general query-optimization framework, we develop techniques for determining the key of a (regular or restructured) view, and show how this information can be used to further optimize a rewritten query. It is straightforward to integrate all our algorithms and techniques into standard query-optimization algorithms. Our extensive experimental results illustrate how using restructured views (in addition to regular views) in query optimization can result in a significant reduction in query-processing costs compared to a system that uses only regular views.}, number={3}, journal={INFORMATION SYSTEMS}, author={Chen, Dongfeng and Chirkova, Rada and Sadri, Fereidoon}, year={2009}, month={May}, pages={353–370} }
 @inbook{kormilitsin_chirkova_fathi_stallmann_2009, title={Systematic Exploration of Efficient Query Plans for Automated Database Restructuring}, ISBN={9783642039720 9783642039737}, ISSN={0302-9743 1611-3349}, url={http://dx.doi.org/10.1007/978-3-642-03973-7_11}, DOI={10.1007/978-3-642-03973-7_11}, abstractNote={We consider the problem of selecting views and indexes that minimize the evaluation costs of the important queries under an upper bound on the disk space available for storing the views/indexes selected to be materialized. We propose a novel end-to-end approach that focuses on systematic exploration of plans for evaluating the queries. Specifically, we propose a framework (architecture) and algorithms that enable selection of views/indexes that contribute to the most efficient plans for the input queries, subject to the space bound. We present strong optimality guarantees on our architecture. Our algorithms search for sets of competitive plans for queries expressed in the language of conjunctive queries with arithmetic comparisons. This language captures the full expressive power of SQL select-project-join queries, which are common in practical database systems. Our experimental results demonstrate the competitiveness and scalability of our approach.}, booktitle={Advances in Databases and Information Systems}, publisher={Springer Berlin Heidelberg}, author={Kormilitsin, Maxim and Chirkova, Rada and Fathi, Yahya and Stallmann, Matthias}, year={2009}, pages={133–148} }
 @misc{gou_chirkova_2007, title={Efficiently querying large XML data repositories: A survey}, volume={19}, ISSN={["1041-4347"]}, DOI={10.1109/tkde.2007.1060}, abstractNote={Extensible markup language (XML) is emerging as a de facto standard for information exchange among various applications on the World Wide Web. There has been a growing need for developing high-performance techniques to query large XML data repositories efficiently. One important problem in XML query processing is twig pattern matching, that is, finding in an XML data tree D all matches that satisfy a specified twig (or path) query pattern Q. In this survey, we review, classify, and compare major techniques for twig pattern matching. Specifically, we consider two classes of major XML query processing techniques: the relational approach and the native approach. The relational approach directly utilizes existing relational database systems to store and query XML data, which enables the use of all important techniques that have been developed for relational databases, whereas in the native approach, specialized storage and query processing systems tailored for XML data are developed from scratch to further improve XML query performance. As implied by existing work, XML data querying and management are developing in the direction of integrating the relational approach with the native approach, which could result in higher query processing performance and also significantly reduce system reengineering costs.}, number={10}, journal={IEEE TRANSACTIONS ON KNOWLEDGE AND DATA ENGINEERING}, author={Gou, Gang and Chirkova, Rada}, year={2007}, month={Oct}, pages={1381–1403} }
 @article{afrati_chirkova_gergatsoulis_pavlaki_2007, title={View selection for real conjunctive queries}, volume={44}, ISSN={["1432-0525"]}, DOI={10.1007/s00236-007-0046-z}, number={5}, journal={ACTA INFORMATICA}, author={Afrati, Foto and Chirkova, Rada and Gergatsoulis, Manolis and Pavlaki, Vassia}, year={2007}, month={Sep}, pages={289–321} }
 @article{chirkova_li_li_2006, title={Answering queries using materialized views with minimum size}, volume={15}, ISSN={["0949-877X"]}, DOI={10.1007/s00778-005-0162-8}, abstractNote={In this paper, we study the following problem. Given a database and a set of queries, we want to find a set of views that can compute the answers to the queries, such that the amount of space, in bytes, required to store the viewset is minimum on the given database. (We also handle problem instances where the input has a set of database instances, as described by an oracle that returns the sizes of view relations for given view definitions.) This problem is important for applications such as distributed databases, data warehousing, and data integration. We explore the decidability and complexity of the problem for workloads of conjunctive queries. We show that results differ significantly depending on whether the workload queries have self-joins. Further, for queries without self-joins we describe a very compact search space of views, which contains all views in at least one optimal viewset. We present techniques for finding a minimum-size viewset for a single query without self-joins by using the shape of the query and its constraints, and validate the approach by extensive experiments.}, number={3}, journal={VLDB JOURNAL}, author={Chirkova, Rada and Li, Chen and Li, Jia}, year={2006}, month={Sep}, pages={191–210} }
 @inbook{afrati_chirkova_gergatsoulis_pavlaki_2006, title={Finding equivalent rewritings in the presence of arithmetic comparisons}, volume={3896}, DOI={10.1007/11687238_55}, abstractNote={The problem of rewriting queries using views has received significant attention because of its applications in a wide variety of data-management problems. For select-project-join SQL (a.k.a. conjunctive) queries and views, there are efficient algorithms in the literature, which find equivalent and maximally contained rewritings. In the presence of arithmetic comparisons (ACs) the problem becomes more complex. We do not know how to find maximally contained rewritings in the general case. There are algorithms which find maximally contained rewritings only for special cases such as when ACs are restricted to be semi-interval. However, we know that the problem of finding an equivalent rewriting (if there exists one) in the presence of ACs is decidable, yet still doubly exponential. This complexity calls for an efficient algorithm which will perform better on average than the complete enumeration algorithm. In this work we present such an algorithm which is sound and complete. Its efficiency lies in that it considers fewer candidate rewritings because it includes a preliminary test to decide for each view whether it is potentially useful in some rewriting.}, booktitle={Advances in database technology :
EDBT 2006 : 10th International Conference on Extending Database Technology, Munich, Germany, March 26-31, 2006: Proceedings (Lecture notes in computer science; 3896)}, publisher={Berlin: Springer}, author={Afrati, F. and Chirkova, R. and Gergatsoulis, M. and Pavlaki, V.}, year={2006}, pages={942–960} }
 @inbook{li_talebi_chirkova_fathi_2005, title={A Formal Model for the Problem of View Selection for Aggregate Queries}, ISBN={9783540285854 9783540318958}, ISSN={0302-9743 1611-3349}, url={http://dx.doi.org/10.1007/11547686_10}, DOI={10.1007/11547686_10}, abstractNote={We present a formal analysis of the following view-selection problem: Given a set of queries and a database, return definitions of views that, when materialized in the database, would reduce the evaluation costs of the queries. Optimizing the layout of stored data using view selection has a direct impact on the performance of the entire database system. At the same time, the optimization problem is intractable, even under natural restrictions on the types of queries of interest. In this paper we use an integer-programming model to obtain optimal solutions to the problem of view selection for aggregate queries on data warehouses. We also report the results of the post-optimality analysis that we performed to determine/observe the impact of changing certain input characteristics on the optimal solution.}, booktitle={Advances in Databases and Information Systems}, publisher={Springer Berlin Heidelberg}, author={Li, Jingni and Talebi, Zohreh Asgharzadeh and Chirkova, Rada and Fathi, Yahya}, year={2005}, pages={125–138} }
 @inbook{afrati_chirkova_gupta_loftis_2005, title={Designing and using views to improve performance of aggregate queries (extended abstract)}, volume={3453}, ISBN={3540253343}, DOI={10.1007/11408079_48}, abstractNote={Data-intensive systems routinely use derived data (e.g., indexes or materialized views) to improve query-evaluation performance. We present a system architecture for Query-Performance Enhancement by Tuning (QPET), which combines design and use of derived data in an end-to-end approach to automated query-performance tuning. Our focus is on a tradeo. between (1) the amount of system resources spent on designing derived data and on keeping the data up to date, and (2) the degree of the resulting improvement in query performance. From the technical point of view, the novelty that we introduce is that we combine aggregate query rewriting techniques [1, 2] and view selection techniques [3] to achieve our goal.}, booktitle={Database systems for advanced applications: 10th international conference, DASFAA 2005, Beijing, China, April 17-20, 2005: Proceedings (Lecture notes in computer science ; 3454)}, publisher={Berlin; New York: Springer}, author={Afrati, F. and Chirkova, R. and Gupta, S. and Loftis, C.}, editor={L. Zhou, B.C. Ooi and Meng, X.Editors}, year={2005}, pages={548–554} }
 @inbook{afrati_chirkova_gergatsoulis_pavlaki_2005, title={Designing views to efficiently answer real SQL queries}, volume={3607}, ISBN={3540278729}, DOI={10.1007/11527862_26}, abstractNote={The problem of optimizing queries in the presence of materialized views and the related view-design problem have recently attracted a lot of attention. Significant research results have been reported, and materialized views are increasingly used in query evaluation in commercial data-management systems. At the same time, most results in the literature assume set-theoretic semantics, whereas SQL queries have bag-theoretic semantics (duplicates are not eliminated unless explicitly requested). This paper presents results on selecting views to answer queries in relational databases under set, bag, and bag-set semantics. The results can be used under each of the three assumptions, to find sound and complete algorithms for designing views and rewriting queries efficiently.}, booktitle={Abstraction, reformulation and approximation: 6th international symposium, SARA 2005, Airth Castle, Scotland, UK, July 26-29, 2005: proceedings
(Lecture notes in computer science, Lecture notes in artificial intelligence; 3607)}, publisher={Berlin; New York: Springer}, author={Afrati, F. and Chirkova, R. and Gergatsoulis, M. and Pavlaki, V.}, editor={J-D. Zucker and Saitta, L.Editors}, year={2005}, pages={332–346} }
 @inbook{afrati_chirkova_2005, title={Selecting and using views to compute aggregate queries (extended abstract)}, volume={3363}, ISBN={3540242880}, DOI={10.1007/978-3-540-30570-5_26}, abstractNote={We consider a workload of aggregate queries and investigate the problem of selecting views that (1) provide equivalent rewritings for all queries, and (2) are optimal, in that the cost of evaluating the query workload is minimized. We consider conjunctive views and rewritings, with or without aggregation; in each rewriting, only one view contributes to computing the aggregated query output. We look at query rewriting using existing views and at view selection. In the query-rewriting problem, we give su.cient and necessary conditions for a rewriting to exist. For view selection, we prove complexity results. Finally, we give algorithms for obtaining rewritings and selecting views.}, booktitle={Database theory: ICDT 2005, 10th international conference, Edinburgh, UK, January 5-7, 2005: Proceedings (Lecture notes in computer science ; 3363)}, publisher={Berlin; New York: Springer}, author={Afrati, F. and Chirkova, R.}, editor={T. Eiter and Libkin, L.Editors}, year={2005}, pages={383–397} }
 @inbook{petrie_genesereth_bjornsson_chirkova_ekstrom_gomi_hinrichs_hoskins_kassoff_kato_et al._2004, title={Adding AI to Web Services}, ISBN={9783540208686 9783540246121}, ISSN={0302-9743 1611-3349}, url={http://dx.doi.org/10.1007/978-3-540-24612-1_23}, DOI={10.1007/978-3-540-24612-1_23}, abstractNote={The FX-Project consisted of members of the Stanford Logic Group industrial visitors from NEC and Intec Web & Genome working together to develop a new technologies based upon the combination of web services and techniques from artificial intelligence using our experience in AI-based software agents. This two-year project ran from April of 2001 until the end of March 2002 and explored the then emerging functionality of web services. This paper is a result of our findings.}, booktitle={Agent-Mediated Knowledge Management}, publisher={Springer Berlin Heidelberg}, author={Petrie, Charles and Genesereth, Michael and Bjornsson, Hans and Chirkova, Rada and Ekstrom, Martin and Gomi, Hidehito and Hinrichs, Tim and Hoskins, Rob and Kassoff, Michael and Kato, Daishi and et al.}, year={2004}, pages={322–338} }
 @article{bilgin_chirkova_salo_singh_2004, title={Deriving efficient SQL sequences via read-aheads}, volume={3181}, ISBN={354022937X}, url={https://publons.com/publon/21294482/}, DOI={10.1007/978-3-540-30076-2_30}, abstractNote={Modern information system architectures place applications in an application server and persistent objects in a relational database. In this setting, we consider the problem of improving application throughput; our proposed solution uses data prefetching (read-aheads) to minimize the total data-access time of an application, in a manner that affects neither the application code nor the backend DBMS. Our methodology is based on analyzing and automatically merging SQL queries to produce query sequences with low total response time, in ways that exploit the application’s data-access patterns. The proposed approach is independent of the application domain and can be viewed as a component of container managed persistence that can be implemented in middleware. This paper describes our proposed framework for using generic data-access patterns to improve application throughput and reports preliminary experimental results on discovering key parameters that influence the trade-offs in producing efficient merged SQL queries. The approach is evaluated in the context of a financial domain, which yields the kinds of natural conceptual relationships where our approach is valuable.}, journal={Lecture Notes in Computer Science}, publisher={Berlin; New York: Springer}, author={Bilgin, A. S. and Chirkova, R. Y. and Salo, T. J. and Singh, Munindar P.}, year={2004}, pages={299–308} }
 @inbook{shah_chirkova_2003, title={Improving query performance using materialized XML views: A learning-based approach}, volume={2814}, ISBN={3540202579}, DOI={10.1007/978-3-540-39597-3_30}, abstractNote={We consider the problem of improving the efficiency of query processing on an XML interface of a relational database, for predefined query workloads. The main contribution of this paper is to show that selective materialization of data as XML views reduces query-execution costs in relatively static databases. Our learning-based approach precomputes and stores (materializes) parts of the answers to the workload queries as clustered XML views. In addition, the data in the materialized XML clusters are periodically incrementally refreshed and rearranged, to respond to the changes in the query workload. Our experiments show that the approach can significantly reduce processing costs for frequent and important queries on relational databases with XML interfaces.}, booktitle={Conceptual modeling for novel application domains: ER 2003 workshops ECOMO, IWCMQ, AOIS, and XSDM, Chicago, IL, USA, October
13, 2003: proceedings / Manfred Jeusfeld;  Oscar Pastor (eds.). New York: Springer-Verlag, 2003. (Lecture notes in computer science ; 2814).}, publisher={Berlin; New York: Springer}, author={Shah, A. and Chirkova, R.}, year={2003}, pages={297–310} }