13 Search Results for "Chen, Hong"


Document
Improved Algorithms for Online Rent Minimization Problem Under Unit-Size Jobs

Authors: Enze Sun, Zonghan Yang, and Yuhao Zhang

Published in: LIPIcs, Volume 274, 31st Annual European Symposium on Algorithms (ESA 2023)


Abstract
We consider the Online Rent Minimization problem, where online jobs with release times, deadlines, and processing times must be scheduled on machines that can be rented for a fixed length period of T. The objective is to minimize the number of machine rents. This problem generalizes the Online Machine Minimization problem where machines can be rented for an infinite period, and both problems have an asymptotically optimal competitive ratio of O(log(p_max/p_min)) for general processing times, where p_max and p_min are the maximum and minimum processing times respectively. However, for small values of p_max/p_min, a better competitive ratio can be achieved by assuming unit-size jobs. Under this assumption, Devanur et al. (2014) gave an optimal e-competitive algorithm for Online Machine Minimization, and Chen and Zhang (2022) gave a (3e+7) ≈ 15.16-competitive algorithm for Online Rent Minimization. In this paper, we significantly improve the competitive ratio of the Online Rent Minimization problem under unit size to 6, by using a clean oracle-based online algorithm framework.

Cite as

Enze Sun, Zonghan Yang, and Yuhao Zhang. Improved Algorithms for Online Rent Minimization Problem Under Unit-Size Jobs. In 31st Annual European Symposium on Algorithms (ESA 2023). Leibniz International Proceedings in Informatics (LIPIcs), Volume 274, pp. 97:1-97:14, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2023)


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@InProceedings{sun_et_al:LIPIcs.ESA.2023.97,
  author =	{Sun, Enze and Yang, Zonghan and Zhang, Yuhao},
  title =	{{Improved Algorithms for Online Rent Minimization Problem Under Unit-Size Jobs}},
  booktitle =	{31st Annual European Symposium on Algorithms (ESA 2023)},
  pages =	{97:1--97:14},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-295-2},
  ISSN =	{1868-8969},
  year =	{2023},
  volume =	{274},
  editor =	{G{\o}rtz, Inge Li and Farach-Colton, Martin and Puglisi, Simon J. and Herman, Grzegorz},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/LIPIcs.ESA.2023.97},
  URN =		{urn:nbn:de:0030-drops-187500},
  doi =		{10.4230/LIPIcs.ESA.2023.97},
  annote =	{Keywords: Online Algorithm, Scheduling, Machine Minimization, Rent Minimization}
}
Document
Elementary Type Inference

Authors: Jinxu Zhao and Bruno C. d. S. Oliveira

Published in: LIPIcs, Volume 222, 36th European Conference on Object-Oriented Programming (ECOOP 2022)


Abstract
Languages with polymorphic type systems are made convenient to use by employing type inference to avoid redundant type information. Unfortunately, features such as impredicative types and subtyping make complete type inference very challenging or impossible to realize. This paper presents a form of partial type inference called elementary type inference. Elementary type inference adopts the idea of inferring only monotypes from past work on predicative higher-ranked polymorphism. This idea is extended with the addition of explicit type applications that work for any polytypes. Thus easy (predicative) instantiations can be inferred, while all other (impredicative) instantiations are always possible with explicit type applications without any compromise in expressiveness. Our target is a System F extension with top and bottom types, similar to the language employed by Pierce and Turner in their seminal work on local type inference. We show a sound, complete and decidable type system for a calculus called F_{< :}^e, that targets that extension of System F. A key design choice in F_{< :}^e is to consider top and bottom types as polytypes only. An important technical challenge is that the combination of predicative implicit instantiation and impredicative explicit type applications, in the presence of standard subtyping rules, is non-trivial. Without some restrictions, key properties, such as subsumption and stability of type substitution lemmas, break. To address this problem we introduce a variant of polymorphic subtyping called stable subtyping with some mild restrictions on implicit instantiation. All the results are mechanically formalized in the Abella theorem prover.

Cite as

Jinxu Zhao and Bruno C. d. S. Oliveira. Elementary Type Inference. In 36th European Conference on Object-Oriented Programming (ECOOP 2022). Leibniz International Proceedings in Informatics (LIPIcs), Volume 222, pp. 2:1-2:28, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2022)


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@InProceedings{zhao_et_al:LIPIcs.ECOOP.2022.2,
  author =	{Zhao, Jinxu and Oliveira, Bruno C. d. S.},
  title =	{{Elementary Type Inference}},
  booktitle =	{36th European Conference on Object-Oriented Programming (ECOOP 2022)},
  pages =	{2:1--2:28},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-225-9},
  ISSN =	{1868-8969},
  year =	{2022},
  volume =	{222},
  editor =	{Ali, Karim and Vitek, Jan},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/LIPIcs.ECOOP.2022.2},
  URN =		{urn:nbn:de:0030-drops-162303},
  doi =		{10.4230/LIPIcs.ECOOP.2022.2},
  annote =	{Keywords: Type Inference}
}
Document
A Generalization of Self-Improving Algorithms

Authors: Siu-Wing Cheng, Man-Kwun Chiu, Kai Jin, and Man Ting Wong

Published in: LIPIcs, Volume 164, 36th International Symposium on Computational Geometry (SoCG 2020)


Abstract
Ailon et al. [SICOMP'11] proposed self-improving algorithms for sorting and Delaunay triangulation (DT) when the input instances x₁,⋯,x_n follow some unknown product distribution. That is, x_i comes from a fixed unknown distribution 𝒟_i, and the x_i’s are drawn independently. After spending O(n^{1+ε}) time in a learning phase, the subsequent expected running time is O((n+ H)/ε), where H ∈ {H_S,H_DT}, and H_S and H_DT are the entropies of the distributions of the sorting and DT output, respectively. In this paper, we allow dependence among the x_i’s under the group product distribution. There is a hidden partition of [1,n] into groups; the x_i’s in the k-th group are fixed unknown functions of the same hidden variable u_k; and the u_k’s are drawn from an unknown product distribution. We describe self-improving algorithms for sorting and DT under this model when the functions that map u_k to x_i’s are well-behaved. After an O(poly(n))-time training phase, we achieve O(n + H_S) and O(nα(n) + H_DT) expected running times for sorting and DT, respectively, where α(⋅) is the inverse Ackermann function.

Cite as

Siu-Wing Cheng, Man-Kwun Chiu, Kai Jin, and Man Ting Wong. A Generalization of Self-Improving Algorithms. In 36th International Symposium on Computational Geometry (SoCG 2020). Leibniz International Proceedings in Informatics (LIPIcs), Volume 164, pp. 29:1-29:13, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2020)


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@InProceedings{cheng_et_al:LIPIcs.SoCG.2020.29,
  author =	{Cheng, Siu-Wing and Chiu, Man-Kwun and Jin, Kai and Wong, Man Ting},
  title =	{{A Generalization of Self-Improving Algorithms}},
  booktitle =	{36th International Symposium on Computational Geometry (SoCG 2020)},
  pages =	{29:1--29:13},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-143-6},
  ISSN =	{1868-8969},
  year =	{2020},
  volume =	{164},
  editor =	{Cabello, Sergio and Chen, Danny Z.},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/LIPIcs.SoCG.2020.29},
  URN =		{urn:nbn:de:0030-drops-121873},
  doi =		{10.4230/LIPIcs.SoCG.2020.29},
  annote =	{Keywords: expected running time, entropy, sorting, Delaunay triangulation}
}
Document
Dynamic Distribution-Sensitive Point Location

Authors: Siu-Wing Cheng and Man-Kit Lau

Published in: LIPIcs, Volume 164, 36th International Symposium on Computational Geometry (SoCG 2020)


Abstract
We propose a dynamic data structure for the distribution-sensitive point location problem. Suppose that there is a fixed query distribution in ℝ², and we are given an oracle that can return in O(1) time the probability of a query point falling into a polygonal region of constant complexity. We can maintain a convex subdivision S with n vertices such that each query is answered in O(OPT) expected time, where OPT is the minimum expected time of the best linear decision tree for point location in S. The space and construction time are O(n log² n). An update of S as a mixed sequence of k edge insertions and deletions takes O(k log⁵ n) amortized time. As a corollary, the randomized incremental construction of the Voronoi diagram of n sites can be performed in O(n log⁵ n) expected time so that, during the incremental construction, a nearest neighbor query at any time can be answered optimally with respect to the intermediate Voronoi diagram at that time.

Cite as

Siu-Wing Cheng and Man-Kit Lau. Dynamic Distribution-Sensitive Point Location. In 36th International Symposium on Computational Geometry (SoCG 2020). Leibniz International Proceedings in Informatics (LIPIcs), Volume 164, pp. 30:1-30:13, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2020)


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@InProceedings{cheng_et_al:LIPIcs.SoCG.2020.30,
  author =	{Cheng, Siu-Wing and Lau, Man-Kit},
  title =	{{Dynamic Distribution-Sensitive Point Location}},
  booktitle =	{36th International Symposium on Computational Geometry (SoCG 2020)},
  pages =	{30:1--30:13},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-143-6},
  ISSN =	{1868-8969},
  year =	{2020},
  volume =	{164},
  editor =	{Cabello, Sergio and Chen, Danny Z.},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/LIPIcs.SoCG.2020.30},
  URN =		{urn:nbn:de:0030-drops-121882},
  doi =		{10.4230/LIPIcs.SoCG.2020.30},
  annote =	{Keywords: dynamic planar point location, convex subdivision, linear decision tree}
}
Document
Random Sampling and Size Estimation Over Cyclic Joins

Authors: Yu Chen and Ke Yi

Published in: LIPIcs, Volume 155, 23rd International Conference on Database Theory (ICDT 2020)


Abstract
Computing joins is expensive, and often unnecessary when the output size is large. In 1999, Chaudhuri et al. [Surajit Chaudhuri et al., 1999] posed the problem of random sampling over joins as a potentially effective approach to avoiding computing the join in full, while obtaining important statistical information about the join results. Unfortunately, no significant progress has been made in the last 20 years, except for the case of acyclic joins. In this paper, we present the first non-trivial result on sampling over cyclic joins. We show that after a linear-time preprocessing step, a join result can be drawn uniformly at random in expected time O(IN^ρ/OUT), where IN^ρ is known as the AGM bound of the join and OUT is its output size. This result holds for all joins on binary relations, as well as certain joins on relations of higher arity. We further show how this algorithm immediately leads to a join size estimation algorithm with the same running time.

Cite as

Yu Chen and Ke Yi. Random Sampling and Size Estimation Over Cyclic Joins. In 23rd International Conference on Database Theory (ICDT 2020). Leibniz International Proceedings in Informatics (LIPIcs), Volume 155, pp. 7:1-7:18, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2020)


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@InProceedings{chen_et_al:LIPIcs.ICDT.2020.7,
  author =	{Chen, Yu and Yi, Ke},
  title =	{{Random Sampling and Size Estimation Over Cyclic Joins}},
  booktitle =	{23rd International Conference on Database Theory (ICDT 2020)},
  pages =	{7:1--7:18},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-139-9},
  ISSN =	{1868-8969},
  year =	{2020},
  volume =	{155},
  editor =	{Lutz, Carsten and Jung, Jean Christoph},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/LIPIcs.ICDT.2020.7},
  URN =		{urn:nbn:de:0030-drops-119315},
  doi =		{10.4230/LIPIcs.ICDT.2020.7},
  annote =	{Keywords: Random sampling, joins, join size estimation}
}
Document
Better Practical Algorithms for rSPR Distance and Hybridization Number

Authors: Kohei Yamada, Zhi-Zhong Chen, and Lusheng Wang

Published in: LIPIcs, Volume 143, 19th International Workshop on Algorithms in Bioinformatics (WABI 2019)


Abstract
The problem of computing the rSPR distance of two phylogenetic trees (denoted by RDC) is NP-hard and so is the problem of computing the hybridization number of two phylogenetic trees (denoted by HNC). Since they are important problems in phylogenetics, they have been studied extensively in the literature. Indeed, quite a number of exact or approximation algorithms have been designed and implemented for them. In this paper, we design and implement one exact algorithm for HNC and several approximation algorithms for RDC and HNC. Our experimental results show that the resulting exact program is much faster (namely, more than 80 times faster for the easiest dataset used in the experiments) than the previous best and its superiority in speed becomes even more significant for more difficult instances. Moreover, the resulting approximation programs output much better results than the previous bests; indeed, the outputs are always nearly optimal and often optimal. Of particular interest is the usage of the Monte Carlo tree search (MCTS) method in the design of our approximation algorithms. Our experimental results show that with MCTS, we can often solve HNC exactly within short time.

Cite as

Kohei Yamada, Zhi-Zhong Chen, and Lusheng Wang. Better Practical Algorithms for rSPR Distance and Hybridization Number. In 19th International Workshop on Algorithms in Bioinformatics (WABI 2019). Leibniz International Proceedings in Informatics (LIPIcs), Volume 143, pp. 5:1-5:12, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2019)


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@InProceedings{yamada_et_al:LIPIcs.WABI.2019.5,
  author =	{Yamada, Kohei and Chen, Zhi-Zhong and Wang, Lusheng},
  title =	{{Better Practical Algorithms for rSPR Distance and Hybridization Number}},
  booktitle =	{19th International Workshop on Algorithms in Bioinformatics (WABI 2019)},
  pages =	{5:1--5:12},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-123-8},
  ISSN =	{1868-8969},
  year =	{2019},
  volume =	{143},
  editor =	{Huber, Katharina T. and Gusfield, Dan},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/LIPIcs.WABI.2019.5},
  URN =		{urn:nbn:de:0030-drops-110355},
  doi =		{10.4230/LIPIcs.WABI.2019.5},
  annote =	{Keywords: phylogenetic tree, fixed-parameter algorithms, approximation algorithms, Monte Carlo tree search}
}
Document
Scheduling Self-Suspending Tasks: New and Old Results

Authors: Jian-Jia Chen, Tobias Hahn, Ruben Hoeksma, Nicole Megow, and Georg von der Brüggen

Published in: LIPIcs, Volume 133, 31st Euromicro Conference on Real-Time Systems (ECRTS 2019)


Abstract
In computing systems, a job may suspend itself (before it finishes its execution) when it has to wait for certain results from other (usually external) activities. For real-time systems, such self-suspension behavior has been shown to induce performance degradation. Hence, the researchers in the real-time systems community have devoted themselves to the design and analysis of scheduling algorithms that can alleviate the performance penalty due to self-suspension behavior. As self-suspension and delegation of parts of a job to non-bottleneck resources is pretty natural in many applications, researchers in the operations research (OR) community have also explored scheduling algorithms for systems with such suspension behavior, called the master-slave problem in the OR community. This paper first reviews the results for the master-slave problem in the OR literature and explains their impact on several long-standing problems for scheduling self-suspending real-time tasks. For frame-based periodic real-time tasks, in which the periods of all tasks are identical and all jobs related to one frame are released synchronously, we explore different approximation metrics with respect to resource augmentation factors under different scenarios for both uniprocessor and multiprocessor systems, and demonstrate that different approximation metrics can create different levels of difficulty for the approximation. Our experimental results show that such more carefully designed schedules can significantly outperform the state-of-the-art.

Cite as

Jian-Jia Chen, Tobias Hahn, Ruben Hoeksma, Nicole Megow, and Georg von der Brüggen. Scheduling Self-Suspending Tasks: New and Old Results. In 31st Euromicro Conference on Real-Time Systems (ECRTS 2019). Leibniz International Proceedings in Informatics (LIPIcs), Volume 133, pp. 16:1-16:23, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2019)


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@InProceedings{chen_et_al:LIPIcs.ECRTS.2019.16,
  author =	{Chen, Jian-Jia and Hahn, Tobias and Hoeksma, Ruben and Megow, Nicole and von der Br\"{u}ggen, Georg},
  title =	{{Scheduling Self-Suspending Tasks: New and Old Results}},
  booktitle =	{31st Euromicro Conference on Real-Time Systems (ECRTS 2019)},
  pages =	{16:1--16:23},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-110-8},
  ISSN =	{1868-8969},
  year =	{2019},
  volume =	{133},
  editor =	{Quinton, Sophie},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/LIPIcs.ECRTS.2019.16},
  URN =		{urn:nbn:de:0030-drops-107532},
  doi =		{10.4230/LIPIcs.ECRTS.2019.16},
  annote =	{Keywords: Self-suspension, master-slave problem, computational complexity, speedup factors}
}
Document
Online Makespan Minimization: The Power of Restart

Authors: Zhiyi Huang, Ning Kang, Zhihao Gavin Tang, Xiaowei Wu, and Yuhao Zhang

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


Abstract
We consider the online makespan minimization problem on identical machines. Chen and Vestjens (ORL 1997) show that the largest processing time first (LPT) algorithm is 1.5-competitive. For the special case of two machines, Noga and Seiden (TCS 2001) introduce the SLEEPY algorithm that achieves a competitive ratio of (5 - sqrt{5})/2 ~~ 1.382, matching the lower bound by Chen and Vestjens (ORL 1997). Furthermore, Noga and Seiden note that in many applications one can kill a job and restart it later, and they leave an open problem whether algorithms with restart can obtain better competitive ratios. We resolve this long-standing open problem on the positive end. Our algorithm has a natural rule for killing a processing job: a newly-arrived job replaces the smallest processing job if 1) the new job is larger than other pending jobs, 2) the new job is much larger than the processing one, and 3) the processed portion is small relative to the size of the new job. With appropriate choice of parameters, we show that our algorithm improves the 1.5 competitive ratio for the general case, and the 1.382 competitive ratio for the two-machine case.

Cite as

Zhiyi Huang, Ning Kang, Zhihao Gavin Tang, Xiaowei Wu, and Yuhao Zhang. Online Makespan Minimization: The Power of Restart. In Approximation, Randomization, and Combinatorial Optimization. Algorithms and Techniques (APPROX/RANDOM 2018). Leibniz International Proceedings in Informatics (LIPIcs), Volume 116, pp. 14:1-14:19, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2018)


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@InProceedings{huang_et_al:LIPIcs.APPROX-RANDOM.2018.14,
  author =	{Huang, Zhiyi and Kang, Ning and Tang, Zhihao Gavin and Wu, Xiaowei and Zhang, Yuhao},
  title =	{{Online Makespan Minimization: The Power of Restart}},
  booktitle =	{Approximation, Randomization, and Combinatorial Optimization. Algorithms and Techniques (APPROX/RANDOM 2018)},
  pages =	{14:1--14:19},
  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-dev.dagstuhl.de/entities/document/10.4230/LIPIcs.APPROX-RANDOM.2018.14},
  URN =		{urn:nbn:de:0030-drops-94182},
  doi =		{10.4230/LIPIcs.APPROX-RANDOM.2018.14},
  annote =	{Keywords: Online Scheduling, Makespan Minimization, Identical Machines}
}
Document
Sink Evacuation on Trees with Dynamic Confluent Flows

Authors: Di Chen and Mordecai Golin

Published in: LIPIcs, Volume 64, 27th International Symposium on Algorithms and Computation (ISAAC 2016)


Abstract
Let G = (V, E) be a graph modelling a building or road network in which edges have-both travel times (lengths) and capacities associated with them. An edge’s capacity is the number of people that can enter that edge in a unit of time. In emergencies, people evacuate towards the exits. If too many people try to evacuate through the same edge, congestion builds up and slows down the evacuation. Graphs with both lengths and capacities are known as Dynamic Flow networks. An evacuation plan for G consists of a choice of exit locations and a partition of the people at the vertices into groups, with each group evacuating to the same exit. The evacuation time of a plan is the time it takes until the last person evacuates. The k-sink evacuation problem is to provide an evacuation plan with k exit locations that minimizes the evacuation time. It is known that this problem is NP-Hard for general graphs but no polynomial time algorithm was previously known even for the case of G a tree. This paper presents an O(nk^2 log^5 n) algorithm for the k-sink evacuation problem on trees, which can also be applied to a more general class of problems.

Cite as

Di Chen and Mordecai Golin. Sink Evacuation on Trees with Dynamic Confluent Flows. In 27th International Symposium on Algorithms and Computation (ISAAC 2016). Leibniz International Proceedings in Informatics (LIPIcs), Volume 64, pp. 25:1-25:13, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2016)


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@InProceedings{chen_et_al:LIPIcs.ISAAC.2016.25,
  author =	{Chen, Di and Golin, Mordecai},
  title =	{{Sink Evacuation on Trees with Dynamic Confluent Flows}},
  booktitle =	{27th International Symposium on Algorithms and Computation (ISAAC 2016)},
  pages =	{25:1--25:13},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-026-2},
  ISSN =	{1868-8969},
  year =	{2016},
  volume =	{64},
  editor =	{Hong, Seok-Hee},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/LIPIcs.ISAAC.2016.25},
  URN =		{urn:nbn:de:0030-drops-67951},
  doi =		{10.4230/LIPIcs.ISAAC.2016.25},
  annote =	{Keywords: Sink Evacuation, Dynamic Flow, Facility Location, Parametric Search}
}
Document
Adaptivity vs. Postselection, and Hardness Amplification for Polynomial Approximation

Authors: Lijie Chen

Published in: LIPIcs, Volume 64, 27th International Symposium on Algorithms and Computation (ISAAC 2016)


Abstract
We study the following problem: with the power of postselection (classically or quantumly), what is your ability to answer adaptive queries to certain languages? More specifically, for what kind of computational classes C, we have P^C belongs to PostBPP or PostBQP? While a complete answer to the above question seems impossible given the development of present computational complexity theory. We study the analogous question in query complexity, which sheds light on the limitation of relativized methods (the relativization barrier) to the above question. Informally, we show that, for a partial function f, if there is no efficient small bounded-error algorithm for f classically or quantumly, then there is no efficient postselection bounded-error algorithm to answer adaptive queries to f classically or quantumly. Our results imply a new proof for the classical oracle separation P^{NP^O} notsubset PP^O, which is arguably more elegant. They also lead to a new oracle separation P^{SZK^O} notsubset PP^O, which is close to an oracle separation between SZK and PP - an open problem in the field of oracle separations. Our result also implies a hardness amplification construction for polynomial approximation: given a function f on n bits, we construct an adaptive-version of f, denoted by F, on O(m·n) bits, such that if f requires large degree to approximate to error 2/3 in a certain one-sided sense, then F requires large degree to approximate even to error 1/2 - 2^{-m}. Our construction achieves the same amplification in the work of Thaler (ICALP, 2016), by composing a function with O(log n) deterministic query complexity, which is in sharp contrast to all the previous results where the composing amplifiers are all hard functions in a certain sense.

Cite as

Lijie Chen. Adaptivity vs. Postselection, and Hardness Amplification for Polynomial Approximation. In 27th International Symposium on Algorithms and Computation (ISAAC 2016). Leibniz International Proceedings in Informatics (LIPIcs), Volume 64, pp. 26:1-26:12, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2016)


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@InProceedings{chen:LIPIcs.ISAAC.2016.26,
  author =	{Chen, Lijie},
  title =	{{Adaptivity vs. Postselection, and Hardness Amplification for Polynomial Approximation}},
  booktitle =	{27th International Symposium on Algorithms and Computation (ISAAC 2016)},
  pages =	{26:1--26:12},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-026-2},
  ISSN =	{1868-8969},
  year =	{2016},
  volume =	{64},
  editor =	{Hong, Seok-Hee},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/LIPIcs.ISAAC.2016.26},
  URN =		{urn:nbn:de:0030-drops-67960},
  doi =		{10.4230/LIPIcs.ISAAC.2016.26},
  annote =	{Keywords: approximate degree, postselection, hardness amplification, adaptivity}
}
Document
An Improved Tax Scheme for Selfish Routing

Authors: Te-Li Wang, Chih-Kuan Yeh, and Ho-Lin Chen

Published in: LIPIcs, Volume 64, 27th International Symposium on Algorithms and Computation (ISAAC 2016)


Abstract
We study the problem of routing traffic for independent selfish users in a congested network to minimize the total latency. The inefficiency of selfish routing motivates regulating the flow of the system to lower the total latency of the Nash Equilibrium by economic incentives or penalties. When applying tax to the routes, we follow the definition of [Christodoulou et al, Algorithmica, 2014] to define ePoA as the Nash total cost including tax in the taxed network over the optimal cost in the original network. We propose a simple tax scheme consisting of step functions imposed on the links. The tax scheme can be applied to routing games with parallel links, affine cost functions and single-commodity networks to lower the ePoA to at most 4/3 - epsilon, where epsilon only depends on the discrepancy between the links. We show that there exists a tax scheme in the two link case with an ePoA upperbound less than 1.192 which is almost tight. Moreover, we design another tax scheme that lowers ePoA down to 1.281 for routing games with groups of links such that links in the same group are similar to each other and groups are sufficiently different.

Cite as

Te-Li Wang, Chih-Kuan Yeh, and Ho-Lin Chen. An Improved Tax Scheme for Selfish Routing. In 27th International Symposium on Algorithms and Computation (ISAAC 2016). Leibniz International Proceedings in Informatics (LIPIcs), Volume 64, pp. 61:1-61:12, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2016)


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@InProceedings{wang_et_al:LIPIcs.ISAAC.2016.61,
  author =	{Wang, Te-Li and Yeh, Chih-Kuan and Chen, Ho-Lin},
  title =	{{An Improved Tax Scheme for Selfish Routing}},
  booktitle =	{27th International Symposium on Algorithms and Computation (ISAAC 2016)},
  pages =	{61:1--61:12},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-026-2},
  ISSN =	{1868-8969},
  year =	{2016},
  volume =	{64},
  editor =	{Hong, Seok-Hee},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/LIPIcs.ISAAC.2016.61},
  URN =		{urn:nbn:de:0030-drops-68308},
  doi =		{10.4230/LIPIcs.ISAAC.2016.61},
  annote =	{Keywords: selfish routing, price of anarchy, tax}
}
Document
09181 Working Group on Hybridization between R&S, DoE and Optimization

Authors: Chun-Hung Chen, Liu Hong, Paul B. Kantor, David P. Morton, Juta Pichitlamken, and Matthias Seeger

Published in: Dagstuhl Seminar Proceedings, Volume 9181, Sampling-based Optimization in the Presence of Uncertainty (2009)


Abstract
This is the report of the working group on the relation between, or hybrid combination of design experiment optimization and R&S. The rapporteur, Paul Kantor, learned a great deal at the conference which he summarized by sharing the cartoon shown here. ("A student asking the teacher'... may i be excused, my is full" (from a 1986 cartoon by Gary Larson) - omitted here for copyright reasons).

Cite as

Chun-Hung Chen, Liu Hong, Paul B. Kantor, David P. Morton, Juta Pichitlamken, and Matthias Seeger. 09181 Working Group on Hybridization between R&S, DoE and Optimization. In Sampling-based Optimization in the Presence of Uncertainty. Dagstuhl Seminar Proceedings, Volume 9181, pp. 1-14, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2009)


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@InProceedings{chen_et_al:DagSemProc.09181.3,
  author =	{Chen, Chun-Hung and Hong, Liu and Kantor, Paul B. and Morton, David P. and Pichitlamken, Juta and Seeger, Matthias},
  title =	{{09181 Working Group on Hybridization between R\&S, DoE and Optimization}},
  booktitle =	{Sampling-based Optimization in the Presence of Uncertainty},
  pages =	{1--14},
  series =	{Dagstuhl Seminar Proceedings (DagSemProc)},
  ISSN =	{1862-4405},
  year =	{2009},
  volume =	{9181},
  editor =	{J\"{u}rgen Branke and Barry L. Nelson and Warren Buckler Powell and Thomas J. Santner},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/DagSemProc.09181.3},
  URN =		{urn:nbn:de:0030-drops-21172},
  doi =		{10.4230/DagSemProc.09181.3},
  annote =	{Keywords: }
}
Document
08043 Summary – Perspectives Workshop: Telecommunication Economics

Authors: Heikki Hammainen, Hong Chen, Aiko Pras, George Huitema, Martin Waldburger, David Hausheer, Panayotis Antoniadis, Peter Reichl, Jerzy Kubasik, and Burkhard Stiller

Published in: Dagstuhl Seminar Proceedings, Volume 8043, Perspectives Workshop: Telecommunication Economics (2008)


Abstract
The telecommunications sector and the Internet section of Internet Service Providers (ISP) have become a dynamic key area for the economic development of industrialized nations in the world. It is in constant evolution. Because of intense competition, telecommunications companies and ISPs are forced to diversify their offers and thus to propose an increasing number of services. However, economic analysis often ignores important technical aspects of telecommunications and is not aware of new developments. Engineering models often ignore economic factors. Thus, the design and deployment of future networks that incorporate new services are subject to uncertainties such as equipment and capacity prices (due to technological innovation), demand and supply for services (due to competition). Seeing leading researchers bringing together with various backgrounds, all working on innovative aspects of technical, techno-economic, social, and regulatory issues, lead to the following four main areas that have been – partially – tackled in an integrated manner: - Architectural side, - Social side, - Economic and business side, and - Regulatory side.

Cite as

Heikki Hammainen, Hong Chen, Aiko Pras, George Huitema, Martin Waldburger, David Hausheer, Panayotis Antoniadis, Peter Reichl, Jerzy Kubasik, and Burkhard Stiller. 08043 Summary – Perspectives Workshop: Telecommunication Economics. In Perspectives Workshop: Telecommunication Economics. Dagstuhl Seminar Proceedings, Volume 8043, pp. 1-8, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2008)


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@InProceedings{hammainen_et_al:DagSemProc.08043.1,
  author =	{Hammainen, Heikki and Chen, Hong and Pras, Aiko and Huitema, George and Waldburger, Martin and Hausheer, David and Antoniadis, Panayotis and Reichl, Peter and Kubasik, Jerzy and Stiller, Burkhard},
  title =	{{08043 Summary – Perspectives Workshop: Telecommunication Economics}},
  booktitle =	{Perspectives Workshop: Telecommunication Economics},
  pages =	{1--8},
  series =	{Dagstuhl Seminar Proceedings (DagSemProc)},
  ISSN =	{1862-4405},
  year =	{2008},
  volume =	{8043},
  editor =	{Burkhard Stiller},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/DagSemProc.08043.1},
  URN =		{urn:nbn:de:0030-drops-14900},
  doi =		{10.4230/DagSemProc.08043.1},
  annote =	{Keywords: Telecommunication and Internet Services, Tariffing and Pricing, Personalization, Incentives, Value Chain, Accounting, Contracts and Legal Domains, Quality-of-Experience, Dynamic Business, and Competition}
}
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