Krysta Svore - Academia.edu (original) (raw)

Papers by Krysta Svore

Proceeding of the 33rd international ACM SIGIR conference on Research and development in information retrieval - SIGIR '10, 2010

An arbitrarily reliable quantum computer can be efficiently constructed from noisy components usi... more An arbitrarily reliable quantum computer can be efficiently constructed from noisy components using a recursive simulation procedure, provided that those components fail with probability less than the fault-tolerance threshold. Recent estimates of the threshold are near some experimentally achieved gate fidelities. However, the landscape of threshold estimates includes pseudothresholds, threshold estimates based on a subset of components and a low

We consider a model of quantum computation in which the set of operations is limited to nearest-n... more We consider a model of quantum computation in which the set of operations is limited to nearest-neighbor interactions on a 2D lattice. We model movement of qubits with noisy SWAP operations. For this architecture we design a fault-tolerant coding scheme using the concatenated [[7,1,3]] Steane code. Our scheme is potentially applicable to ion-trap and solid-state quantum technologies. We calculate a

Journal of Computer Security, 2005

We present a component anomaly detector for a host-based intrusion detection system (IDS) for Mic... more We present a component anomaly detector for a host-based intrusion detection system (IDS) for Microsoft Windows. The core of the detector is a learning-based anomaly detection algorithm that de- tects attacks on a host machine by looking for anomalous accesses to the Windows Registry. We present and compare two anomaly detection al- gorithms for use in our IDS system and

Web search is strongly influenced by time. The queries people issue change over time, with some q... more Web search is strongly influenced by time. The queries people issue change over time, with some queries occasionally spiking in popularity (e.g., earthquake) and others remaining relatively constant (e.g., youtube). The documents indexed by the search engine also change, with some documents always being about a particular query (e.g., the Wikipedia page on earthquakes is about the query earthquake) and others being about the query only at a particular point in time (e.g., the New York Times is only about earthquakes following a major seismic activity). The relationship between documents and queries can also change as people's intent changes (e.g., people sought different content for the query earthquake before the Haitian earthquake than they did after). In this paper, we explore how queries, their associated documents, and the query intent change over the course of 10 weeks by analyzing query log data, a daily Web crawl, and periodic human relevance judgments. We identify sever...

Content on the Internet is always changing. We explore the value of biasing search result snippet... more Content on the Internet is always changing. We explore the value of biasing search result snippets towards new webpage content. We present results from a user study comparing traditional query-focused snippets with snippets that emphasize new page content for two query types: general and trending. Our results indicate that searchers prefer the inclusion of temporal information for trending queries but not for general queries, and that this is particularly valuable for pages that have not been recently crawled.

Physical Review Letters, 2015

Recently, it was shown that Repeat-Until-Success (RUS) circuits can achieve a 2.5 times reduction... more Recently, it was shown that Repeat-Until-Success (RUS) circuits can achieve a 2.5 times reduction in expected depth over ancilla-free techniques for single-qubit unitary decomposition. However, the previously best-known algorithm to synthesize RUS circuits requires exponential classical runtime. In this work we present an algorithm to synthesize an RUS circuit to approximate any given singlequbit unitary within precision ε in probabilistically polynomial classical runtime. Our synthesis approach uses the Clifford+T basis, plus one ancilla qubit and measurement. We provide numerical evidence that our RUS circuits have an expected T -count on average 2.5 times lower than the theoretical lower bound of 3 log 2 (1/ε) for ancilla-free single-qubit circuit decomposition.

Proceedings of the 21st international conference on World Wide Web - WWW '12, 2012

User behavior on the Web changes over time. For example, the queries that people issue to search ... more User behavior on the Web changes over time. For example, the queries that people issue to search engines, and the underlying informational goals behind the queries vary over time. In this paper, we examine how to model and predict user behavior over time. We develop a temporal modeling framework adapted from physics and signal processing that can be used to predict time-varying user behavior using smoothing and trends. We also explore other dynamics of Web behaviors, such as the detection of periodicities and surprises. We develop a learning procedure that can be used to construct models of users' activities based on features of current and historical behaviors. The results of experiments indicate that by using our framework to predict user behavior, we can achieve significant improvements in prediction compared to baseline models that weight historical evidence the same for all queries. We also develop a novel learning algorithm that explicitly learns when to apply a given prediction model among a set of such models. Our improved temporal modeling of user behavior can be used to enhance query suggestions, crawling policies, and result ranking.

Proceedings of the 35th international ACM SIGIR conference on Research and development in information retrieval - SIGIR '12, 2012

Proceedings of the fourth ACM international conference on Web search and data mining - WSDM '11, 2011

Proceedings of the 2009 Conference on Empirical Methods in Natural Language Processing Volume 2 - EMNLP '09, 2009

Physical Review Letters, 2014

In a topological quantum computer, universality is achieved by braiding and quantum information i... more In a topological quantum computer, universality is achieved by braiding and quantum information is natively protected from small local errors. We address the problem of compiling single-qubit quantum operations into braid representations for non-abelian quasiparticles described by the Fibonacci anyon model. We develop a probabilistically polynomial algorithm that outputs a braid pattern to approximate a given single-qubit unitary to a desired precision. We also classify the single-qubit unitaries that can be implemented exactly by a Fibonacci anyon braid pattern and present an efficient algorithm to produce their braid patterns. Our techniques produce braid patterns that meet the uniform asymptotic lower bound on the compiled circuit depth and thus are depth-optimal asymptotically. Our compiled circuits are significantly shorter than those output by prior state-of-the-art methods, resulting in improvements in depth by factors ranging from 20 to 1000 for precisions ranging between 10 −10 and 10 −30 .

Physical Review A, 2005

We analyze and study the effects of locality on the fault-tolerance threshold for quantum computa... more We analyze and study the effects of locality on the fault-tolerance threshold for quantum computation.

Information Retrieval, 2010

We present a new ranking algorithm that combines the strengths of two previous methods: boosted t... more We present a new ranking algorithm that combines the strengths of two previous methods: boosted tree classification, and LambdaRank, which has been shown to be empirically optimal for a widely used information retrieval measure. Our algorithm is based on boosted regression trees, although the ideas apply to any weak learners, and it is significantly faster in both train and test phases than the state of the art, for comparable accuracy. We also show how to find the optimal linear combination for any two rankers, and we use this method to solve the line search problem exactly during boosting. In addition, we show that starting with a previously trained model, and boosting using its residuals, furnishes an effective technique for model adaptation, and we give significantly improved results for a particularly pressing problem in Web Search -training rankers for markets for which only small amounts of labeled data are available, given a ranker trained on much more data from a larger market.

Computer, 2006

P u b l i s h e d b y t h e I E E E C o m p u t e r S o c i e t y

The design and optimization of quantum circuits is central to quantum computation. This paper pre... more The design and optimization of quantum circuits is central to quantum computation. This paper presents new algorithms for compiling arbitrary 2 n × 2 n unitary matrices into efficient circuits of (n − 1)controlled single-qubit and (n−1)-controlled-NOT gates. We first present a general algebraic optimization technique, which we call the Palindrome Transform, that can be used to minimize the number of selfinverting gates in quantum circuits consisting of concatenations of palindromic subcircuits. For a fixed column ordering of two-level decomposition, we then give an enumerative algorithm for minimal (n − 1)controlled-NOT circuit construction, which we call the Palindromic Optimization Algorithm. Our work dramatically reduces the number of gates generated by the conventional two-level decomposition method for constructing quantum circuits of (n − 1)-controlled single-qubit and (n − 1)-controlled-NOT gates. *

data generated from the same system. Given the success of OCSVMs in other applications, we apply ... more data generated from the same system. Given the success of OCSVMs in other applications, we apply them to the Windows Registry anomaly detection problem. We compare our system to the RAD system using the Probabilistic Anomaly Detection (PAD) algorithm on the same dataset. Surprisingly, we find that PAD outperforms our OCSVM system due to properties of the hierarchical prior incorporated in the PAD algorithm. In the future, these properties may be used to develop an improved kernel and increase the performance of the OCSVM system.