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Michael Christoph Gastpar

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Publications associées (132)

Single-server Multi-user Private Information Retrieval with Side Information

Michael Christoph Gastpar, Su Li

In the problem of private information retrieval with side information, a single user wants to recover one of the K independent messages which are stored at one or multiple servers. The user initially has a subset of messages as side information. The goal o ...

2018

Computable Bounds on the Exploration Bias

Michael Christoph Gastpar, Ibrahim Issa

Adaptive data analysis is known to introduce bias in reported measurements. Russo and Zou [1] recently introduced an information-theoretic framework to study this problem. Herein, this framework is adopted and new dependence measures are introduced to boun ...

2018

Increasing Availability in Distributed Storage Systems via Clustering

Michael Christoph Gastpar, Saeid Sahraei

We introduce the Fixed Cluster Repair System (FCRS) as a novel architecture for Distributed Storage Systems (DSS) that achieves a small repair bandwidth while guaranteeing a high availability. Specifically, we partition the set of servers in a DSS into s c ...

2018

Sum-Rate Capacity for Symmetric Gaussian Multiple Access Channels with Feedback

Michael Christoph Gastpar, Erixhen Sula

The feedback sum-rate capacity is established for the symmetric three-user Gaussian multiple-access channel (GMAC). The main contribution is a converse bound that combines the dependence-balance argument of Hekstra and Willems (1989) with a variant of the ...

2018

A Novel Centralized Strategy for Coded Caching with Non-uniform Demands

Michael Christoph Gastpar, Saeid Sahraei, Pierre Victor Xavier Quinton

Despite significant progress in the caching literature concerning the worst case and uniform average case regimes, the algorithms for caching with nonuniform demands are still at a basic stage and mostly rely on simple grouping and memory-sharing technique ...

2018

A Joint Typicality Approach to Compute–Forward

Michael Christoph Gastpar, Adriano Pastore, Sung Hoon Lim, Chen Feng

This paper presents a joint typicality framework for encoding and decoding nested linear codes in multi-user networks. This framework provides a new perspective on compute–forward within the context of discrete memoryless networks. In particular, it establ ...

2018

Single-server Multi-message Private Information Retrieval with Side Information

Michael Christoph Gastpar, Su Li

We study the problem of single-server multi-message private information retrieval with side information. One user wants to recover N out of K independent messages which are stored at a single server. The user initially possesses a subset of M messages as s ...

IEEE2018

On the Duality between Multiple-Access Codes and Computation Codes

Michael Christoph Gastpar, Jingge Zhu, Sung Hoon Lim

For a two-user Gaussian multiple access channel, computation codes are designed for the scenarios where the decoder is not interested in decoding the two codewords, but only the sum of them. It has been observed that good computation codes should possess s ...

2017

Information-Theoretic Caching: The Multi-User Case

Michael Christoph Gastpar, Chien-Yi Wang, Sung Hoon Lim

In this paper, we consider a cache aided network in which each user is assumed to have individual caches, while upon users’ requests, an update message is sent through a common link to all users. First, we formulate a general information theoretic setting ...

Institute of Electrical and Electronics Engineers2017

Polynomially Solvable Instances of the Shortest and Closest Vector Problems With Applications to Compute-and-Forward

Michael Christoph Gastpar, Saeid Sahraei

A particular instance of the shortest vector problem (SVP) appears in the context of compute-and-forward. Despite the NP-hardness of the SVP, we will show that this certain instance can be solved in complexity order O(nψlog(nψ)) , where ψ=sqrt(P ||h||^2+1) ...

Institute of Electrical and Electronics Engineers2017

Cooperative Data Exchange with Weighted Cost based on d-Basis Construction

Michael Christoph Gastpar, Su Li, Abhin Shah

We consider the cooperative data exchange problem, in which nodes are fully connected with each other. Each node initially only has a subset of the K packets making up a file and wants to recover the whole file. Node i can make a broadcast transmission, wh ...

2017

Towards an algebraic network information theory: Simultaneous joint typicality decoding

Michael Christoph Gastpar, Adriano Pastore, Sung Hoon Lim, Chen Feng

Recent work has employed joint typicality encoding and decoding of nested linear code ensembles to generalize the compute-forward strategy to discrete memoryless multiple-access channels (MACs). An appealing feature of these nested linear code ensembles is ...

2017

Compute-forward multiple access (CFMA) with nested LDPC codes

Michael Christoph Gastpar, Adriano Pastore, Jingge Zhu, Erixhen Sula, Sung Hoon Lim

Inspired by the compute-and-forward scheme from Nazer and Gastpar, a novel multiple-access scheme introduced by Zhu and Gastpar makes use of nested lattice codes and sequential decoding of linear combinations of codewords to recover the individual messages ...

2017

Secure Transmission on the Two-Hop Relay Channel With Scaled Compute-and-Forward

Michael Christoph Gastpar, Jasper Goseling

In this paper, we consider communication on a two-hop channel in which a source wants to send information reliably and securely to the destination via a relay. We consider both the untrusted relay case and the external eavesdropper case. In the untrusted r ...

Institute of Electrical and Electronics Engineers2017

Caching of Bivariate Gaussians with Non-Uniform Preference Probabilities

Michael Christoph Gastpar, Guillaume Jean Op 't Veld

Caching is technique that alleviates networks during peak hours by transmitting partial information before a request for any is made. We study this method in a lossy source coding setting with Gaussian databases. A good caching strategy minimizes the data ...

2017

Cooperative data exchange based on MDS codes

Michael Christoph Gastpar, Su Li

The coded cooperative data exchange problem is studied for the fully connected network. In this problem, each node initially only possesses a subset of the K packets making up the file. Nodes make broadcast transmissions that are received by all other node ...

2017

GDSP: A graphical perspective on the distributed storage systems

Michael Christoph Gastpar, Saeid Sahraei

The classical distributed storage problem can be modeled by a k-uniform complete hyper-graph where vertices represent servers and hyper-edges represent users. Hence each hyper-edge should be able to recover the full file using only the memories of the vert ...

2017

Gaussian Multiple Access via Compute-and-Forward

Michael Christoph Gastpar, Jingge Zhu

Lattice codes used under the compute-and-forward paradigm suggest an alternative strategy for the standard Gaussian multiple-access channel (MAC): the receiver succes- sively decodes the integer linear combinations of the messages until it can invert and r ...

Institute of Electrical and Electronics Engineers2017

On the energy benefit of compute-and-forward for multiple unicasts

Michael Christoph Gastpar, Jasper Goseling

Compute-and-forward (CF) is a technique which exploits broadcast and superposition in wireless networks. In this paper, the CF energy benefit is studied for networks with unicast sessions and modeled by connected graphs. This benefit is defined as the rati ...

Ieee2016

A New Converse Bound for Coded Caching

Michael Christoph Gastpar, Chien-Yi Wang, Sung Hoon Lim

An information-theoretic lower bound is developed for the caching system studied by Maddah-Ali and Niesen. By comparing the proposed lower bound with the decentralized coded caching scheme of Maddah-Ali and Niesen, the optimal memory--rate tradeoff is char ...

2016

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