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Documents authored by Zhao, Yu


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Zhao, Yu

Document
On Closeness to k-Wise Uniformity

Authors: Ryan O'Donnell and Yu Zhao

Published in: LIPIcs, Volume 116, Approximation, Randomization, and Combinatorial Optimization. Algorithms and Techniques (APPROX/RANDOM 2018)


Abstract
A probability distribution over {-1, 1}^n is (epsilon, k)-wise uniform if, roughly, it is epsilon-close to the uniform distribution when restricted to any k coordinates. We consider the problem of how far an (epsilon, k)-wise uniform distribution can be from any globally k-wise uniform distribution. We show that every (epsilon, k)-wise uniform distribution is O(n^{k/2}epsilon)-close to a k-wise uniform distribution in total variation distance. In addition, we show that this bound is optimal for all even k: we find an (epsilon, k)-wise uniform distribution that is Omega(n^{k/2}epsilon)-far from any k-wise uniform distribution in total variation distance. For k=1, we get a better upper bound of O(epsilon), which is also optimal. One application of our closeness result is to the sample complexity of testing whether a distribution is k-wise uniform or delta-far from k-wise uniform. We give an upper bound of O(n^{k}/delta^2) (or O(log n/delta^2) when k = 1) on the required samples. We show an improved upper bound of O~(n^{k/2}/delta^2) for the special case of testing fully uniform vs. delta-far from k-wise uniform. Finally, we complement this with a matching lower bound of Omega(n/delta^2) when k = 2. Our results improve upon the best known bounds from [Alon et al., 2007], and have simpler proofs.

Cite as

Ryan O'Donnell and Yu Zhao. On Closeness to k-Wise Uniformity. In Approximation, Randomization, and Combinatorial Optimization. Algorithms and Techniques (APPROX/RANDOM 2018). Leibniz International Proceedings in Informatics (LIPIcs), Volume 116, pp. 54:1-54:19, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2018)


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@InProceedings{odonnell_et_al:LIPIcs.APPROX-RANDOM.2018.54,
  author =	{O'Donnell, Ryan and Zhao, Yu},
  title =	{{On Closeness to k-Wise Uniformity}},
  booktitle =	{Approximation, Randomization, and Combinatorial Optimization. Algorithms and Techniques (APPROX/RANDOM 2018)},
  pages =	{54:1--54:19},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-085-9},
  ISSN =	{1868-8969},
  year =	{2018},
  volume =	{116},
  editor =	{Blais, Eric and Jansen, Klaus and D. P. Rolim, Jos\'{e} and Steurer, David},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.APPROX-RANDOM.2018.54},
  URN =		{urn:nbn:de:0030-drops-94581},
  doi =		{10.4230/LIPIcs.APPROX-RANDOM.2018.54},
  annote =	{Keywords: k-wise independence, property testing, Fourier analysis, Boolean function}
}
Document
Polynomial Bounds for Decoupling, with Applications

Authors: Ryan O'Donnell and Yu Zhao

Published in: LIPIcs, Volume 50, 31st Conference on Computational Complexity (CCC 2016)


Abstract
Let f(x) = f(x_1, ..., x_n) = sum_{|S|<=k} a_S prod_{i in S} x_i be an n-variate real multilinear polynomial of degree at most k, where S subseteq [n] = {1, 2, ..., n}. For its one-block decoupled version, vf(y,z) = sum_{abs(S)<=k} a_S sum_{i in S}} y_i prod_{j in S\{i}} z_j, we show tail-bound comparisons of the form Pr(abs(vf)(y,z)) > C_k t} <= D_k Pr(abs(f(x)) > t). Our constants C_k, D_k are significantly better than those known for "full decoupling". For example, when x, y, z are independent Gaussians we obtain C_k = D_k = O(k); when x, by, z are +/-1 random variables we obtain C_k = O(k^2), D_k = k^{O(k)}. By contrast, for full decoupling only C_k = D_k = k^{O(k)} is known in these settings. We describe consequences of these results for query complexity (related to conjectures of Aaronson and Ambainis) and for analysis of Boolean functions (including an optimal sharpening of the DFKO Inequality).

Cite as

Ryan O'Donnell and Yu Zhao. Polynomial Bounds for Decoupling, with Applications. In 31st Conference on Computational Complexity (CCC 2016). Leibniz International Proceedings in Informatics (LIPIcs), Volume 50, pp. 24:1-24:18, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2016)


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@InProceedings{odonnell_et_al:LIPIcs.CCC.2016.24,
  author =	{O'Donnell, Ryan and Zhao, Yu},
  title =	{{Polynomial Bounds for Decoupling, with Applications}},
  booktitle =	{31st Conference on Computational Complexity (CCC 2016)},
  pages =	{24:1--24:18},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-008-8},
  ISSN =	{1868-8969},
  year =	{2016},
  volume =	{50},
  editor =	{Raz, Ran},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.CCC.2016.24},
  URN =		{urn:nbn:de:0030-drops-58520},
  doi =		{10.4230/LIPIcs.CCC.2016.24},
  annote =	{Keywords: Decoupling, Query Complexity, Fourier Analysis, Boolean Functions}
}

Zhao, Yaoyu

Document
Artifact
Scala with Explicit Nulls (Artifact)

Authors: Abel Nieto, Yaoyu Zhao, Ondřej Lhoták, Angela Chang, and Justin Pu

Published in: DARTS, Volume 6, Issue 2, Special Issue of the 34th European Conference on Object-Oriented Programming (ECOOP 2020)


Abstract
This artifact is a companion to the paper "Scala with Explicit Nulls", where we present a modification to the Scala type system that makes nullability explicit in the types. Specifically, we make reference types non-nullable by default, while still allowing for nullable types via union types. The artifact contains an implementation of this new type system design as a fork of the Dotty (Scala 3) compiler. Additionally, the artifact contains the source code of multiple Scala libraries that we used to evaluate our design.

Cite as

Abel Nieto, Yaoyu Zhao, Ondřej Lhoták, Angela Chang, and Justin Pu. Scala with Explicit Nulls (Artifact). In Special Issue of the 34th European Conference on Object-Oriented Programming (ECOOP 2020). Dagstuhl Artifacts Series (DARTS), Volume 6, Issue 2, pp. 14:1-14:2, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2020)


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@Article{nieto_et_al:DARTS.6.2.14,
  author =	{Nieto, Abel and Zhao, Yaoyu and Lhot\'{a}k, Ond\v{r}ej and Chang, Angela and Pu, Justin},
  title =	{{Scala with Explicit Nulls (Artifact)}},
  pages =	{14:1--14:2},
  journal =	{Dagstuhl Artifacts Series},
  ISSN =	{2509-8195},
  year =	{2020},
  volume =	{6},
  number =	{2},
  editor =	{Nieto, Abel and Zhao, Yaoyu and Lhot\'{a}k, Ond\v{r}ej and Chang, Angela and Pu, Justin},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/DARTS.6.2.14},
  URN =		{urn:nbn:de:0030-drops-132117},
  doi =		{10.4230/DARTS.6.2.14},
  annote =	{Keywords: Scala, Java, nullability, language interoperability, type systems}
}
Document
Scala with Explicit Nulls

Authors: Abel Nieto, Yaoyu Zhao, Ondřej Lhoták, Angela Chang, and Justin Pu

Published in: LIPIcs, Volume 166, 34th European Conference on Object-Oriented Programming (ECOOP 2020)


Abstract
The Scala programming language makes all reference types implicitly nullable. This is a problem, because null references do not support most operations that do make sense on regular objects, leading to runtime errors. In this paper, we present a modification to the Scala type system that makes nullability explicit in the types. Specifically, we make reference types non-nullable by default, while still allowing for nullable types via union types. We have implemented this design for explicit nulls as a fork of the Dotty (Scala 3) compiler. We evaluate our scheme by migrating a number of Scala libraries to use explicit nulls. Finally, we give a denotational semantics of type nullification, the interoperability layer between Java and Scala with explicit nulls. We show a soundness theorem stating that, for variants of System F_ω that model Java and Scala, nullification preserves values of types.

Cite as

Abel Nieto, Yaoyu Zhao, Ondřej Lhoták, Angela Chang, and Justin Pu. Scala with Explicit Nulls. In 34th European Conference on Object-Oriented Programming (ECOOP 2020). Leibniz International Proceedings in Informatics (LIPIcs), Volume 166, pp. 25:1-25:26, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2020)


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@InProceedings{nieto_et_al:LIPIcs.ECOOP.2020.25,
  author =	{Nieto, Abel and Zhao, Yaoyu and Lhot\'{a}k, Ond\v{r}ej and Chang, Angela and Pu, Justin},
  title =	{{Scala with Explicit Nulls}},
  booktitle =	{34th European Conference on Object-Oriented Programming (ECOOP 2020)},
  pages =	{25:1--25:26},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-154-2},
  ISSN =	{1868-8969},
  year =	{2020},
  volume =	{166},
  editor =	{Hirschfeld, Robert and Pape, Tobias},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECOOP.2020.25},
  URN =		{urn:nbn:de:0030-drops-131821},
  doi =		{10.4230/LIPIcs.ECOOP.2020.25},
  annote =	{Keywords: Scala, Java, nullability, language interoperability, type systems}
}

Zhao, Yue

Document
Towards Ontology-Based Program Analysis

Authors: Yue Zhao, Guoyang Chen, Chunhua Liao, and Xipeng Shen

Published in: LIPIcs, Volume 56, 30th European Conference on Object-Oriented Programming (ECOOP 2016)


Abstract
Program analysis is fundamental for program optimizations, debugging, and many other tasks. But developing program analyses has been a challenging and error-prone process for general users. Declarative program analysis has shown the promise to dramatically improve the productivity in the development of program analyses. Current declarative program analysis is however subject to some major limitations in supporting cooperations among analysis tools, guiding program optimizations, and often requires much effort for repeated program preprocessing. In this work, we advocate the integration of ontology into declarative program analysis. As a way to standardize the definitions of concepts in a domain and the representation of the knowledge in the domain, ontology offers a promising way to address the limitations of current declarative program analysis. We develop a prototype framework named PATO for conducting program analysis upon ontology-based program representation. Experiments on six program analyses confirm the potential of ontology for complementing existing declarative program analysis. It supports multiple analyses without separate program preprocessing, promotes cooperative Liveness analysis between two compilers, and effectively guides a data placement optimization for Graphic Processing Units (GPU).

Cite as

Yue Zhao, Guoyang Chen, Chunhua Liao, and Xipeng Shen. Towards Ontology-Based Program Analysis. In 30th European Conference on Object-Oriented Programming (ECOOP 2016). Leibniz International Proceedings in Informatics (LIPIcs), Volume 56, pp. 26:1-26:25, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2016)


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@InProceedings{zhao_et_al:LIPIcs.ECOOP.2016.26,
  author =	{Zhao, Yue and Chen, Guoyang and Liao, Chunhua and Shen, Xipeng},
  title =	{{Towards Ontology-Based Program Analysis}},
  booktitle =	{30th European Conference on Object-Oriented Programming (ECOOP 2016)},
  pages =	{26:1--26:25},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-014-9},
  ISSN =	{1868-8969},
  year =	{2016},
  volume =	{56},
  editor =	{Krishnamurthi, Shriram and Lerner, Benjamin S.},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECOOP.2016.26},
  URN =		{urn:nbn:de:0030-drops-61201},
  doi =		{10.4230/LIPIcs.ECOOP.2016.26},
  annote =	{Keywords: ontology, compiler, program analysis}
}

Zhao, Yuda

Document
Some Lower Bounds in Dynamic Networks with Oblivious Adversaries

Authors: Irvan Jahja, Haifeng Yu, and Yuda Zhao

Published in: LIPIcs, Volume 91, 31st International Symposium on Distributed Computing (DISC 2017)


Abstract
This paper considers several closely-related problems in synchronous dynamic networks with oblivious adversaries, and proves novel Omega(d + poly(m)) lower bounds on their time complexity (in rounds). Here d is the dynamic diameter of the dynamic network and m is the total number of nodes. Before this work, the only known lower bounds on these problems under oblivious adversaries were the trivial Omega(d) lower bounds. Our novel lower bounds are hence the first non-trivial lower bounds and also the first lower bounds with a poly(m) term. Our proof relies on a novel reduction from a certain two-party communication complexity problem. Our central proof technique is unique in the sense that we consider the communication complexity with a special leaker. The leaker helps Alice and Bob in the two-party problem, by disclosing to Alice and Bob certain "non-critical" information about the problem instance that they are solving.

Cite as

Irvan Jahja, Haifeng Yu, and Yuda Zhao. Some Lower Bounds in Dynamic Networks with Oblivious Adversaries. In 31st International Symposium on Distributed Computing (DISC 2017). Leibniz International Proceedings in Informatics (LIPIcs), Volume 91, pp. 29:1-29:16, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2017)


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@InProceedings{jahja_et_al:LIPIcs.DISC.2017.29,
  author =	{Jahja, Irvan and Yu, Haifeng and Zhao, Yuda},
  title =	{{Some Lower Bounds in Dynamic Networks with Oblivious Adversaries}},
  booktitle =	{31st International Symposium on Distributed Computing (DISC 2017)},
  pages =	{29:1--29:16},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-053-8},
  ISSN =	{1868-8969},
  year =	{2017},
  volume =	{91},
  editor =	{Richa, Andr\'{e}a},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.DISC.2017.29},
  URN =		{urn:nbn:de:0030-drops-79690},
  doi =		{10.4230/LIPIcs.DISC.2017.29},
  annote =	{Keywords: dynamic networks, oblivious adversary, adaptive adversary, lower bounds, communication complexity}
}
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