Book Section records
https://feeds.library.caltech.edu/people/Zhou-Hongchao/book_section.rss
A Caltech Library Repository Feedhttp://www.rssboard.org/rss-specificationpython-feedgenenTue, 16 Apr 2024 14:35:53 +0000On the Synthesis of Stochastic Flow Networks
https://resolver.caltech.edu/CaltechAUTHORS:20110331-132532031
Authors: {'items': [{'id': 'Zhou-Hongchao', 'name': {'family': 'Zhou', 'given': 'Hongchao'}}, {'id': 'Chen-Ho-Lin', 'name': {'family': 'Chen', 'given': 'Ho-Lin'}}, {'id': 'Bruck-J', 'name': {'family': 'Bruck', 'given': 'Jehoshua'}, 'orcid': '0000-0001-8474-0812'}]}
Year: 2010
DOI: 10.1109/ISIT.2010.5513754
A stochastic flow network is a directed graph with incoming edges (inputs) and outgoing edges (outputs), tokens enter through the input edges, travel stochastically in the network and can exit the network through the output edges. Each node in the network is a splitter, namely, a token can enter a node through an incoming edge and exit on one of the output edges according to a predefined probability distribution. We address the following synthesis question: Given a finite set of possible splitters and an arbitrary rational probability distribution, design a stochastic flow network, such that every token that enters the input edge will exit the outputs with the prescribed probability distribution. The problem of probability synthesis dates back to von Neummann's 1951 work and was followed, among others, by Knuth and Yao in 1976, who demonstrated that arbitrary rational probabilities can be generated with tree networks; where minimizing the expected path length, the expected number of coin tosses in their paradigm, is the key consideration. Motivated by the synthesis of stochastic DNA based molecular systems, we focus on designing optimal-sized stochastic flow networks (the size of a network is the number of splitters). We assume that each splitter has two outgoing edges and is unbiased (probability 1/2 per output edge). We show that an arbitrary rational probability a/b with a ≤ b ≤ 2^n can be realized by a stochastic flow network of size n, we also show that this is optimal. We note that our stochastic flow networks have feedback (cycles in the network), in fact, we demonstrate that feedback improves the expressibility of stochastic flow networks, since without feedback only probabilities of the form ^a/_2^n) (a an integer) can be realized.https://authors.library.caltech.edu/records/hccfy-ah066Patterned cells for phase change memories
https://resolver.caltech.edu/CaltechAUTHORS:20170213-160905267
Authors: {'items': [{'id': 'Jiang-Anxiao-Andrew', 'name': {'family': 'Jiang', 'given': 'Anxiao (Andrew)'}}, {'id': 'Zhou-Hongchao', 'name': {'family': 'Zhou', 'given': 'Hongchao'}}, {'id': 'Wang-Zhiying', 'name': {'family': 'Wang', 'given': 'Zhiying'}}, {'id': 'Bruck-J', 'name': {'family': 'Bruck', 'given': 'Jehoshua'}, 'orcid': '0000-0001-8474-0812'}]}
Year: 2011
DOI: 10.1109/ISIT.2011.6033979
Phase-change memory (PCM) is an emerging nonvolatile memory technology that promises very high performance. It currently uses discrete cell levels to represent data, controlled by a single amorphous/crystalline domain in a cell. To improve data density, more levels per cell are needed. There exist a number of challenges, including cell programming noise, drifting of cell levels, and the high power requirement for cell programming. In this paper, we present a new cell structure called patterned cell, and explore its data representation schemes. Multiple domains per cell are used, and their connectivity is used to store data. We analyze its storage capacity, and study its error-correction capability and the construction of error-control codes.https://authors.library.caltech.edu/records/dpzzx-7bf24Nonuniform Codes for Correcting Asymmetric Errors
https://resolver.caltech.edu/CaltechAUTHORS:20120406-093123448
Authors: {'items': [{'id': 'Zhou-Hongchao', 'name': {'family': 'Zhou', 'given': 'Hongchao'}}, {'id': 'Jiang-A', 'name': {'family': 'Jiang', 'given': 'Anxiao (Andrew)'}}, {'id': 'Bruck-J', 'name': {'family': 'Bruck', 'given': 'Jehoshua'}, 'orcid': '0000-0001-8474-0812'}]}
Year: 2011
DOI: 10.1109/ISIT.2011.6033689
Codes that correct asymmetric errors have important applications in storage systems, including optical disks and Read Only Memories. The construction of asymmetric error correcting codes is a topic that was studied extensively, however, the existing approach for code construction assumes that every codeword could sustain t asymmetric errors. Our main observation is that in contrast to symmetric errors, where the error probability of a codeword is context independent (since the error probability for 1s and 0s is identical), asymmetric errors are context dependent. For example, the all-1 codeword has a higher error probability than the all-0 codeword (since the only errors are 1 → 0). We call the existing codes uniform codes while we focus on the notion of nonuniform codes, namely, codes whose codewords can tolerate different numbers of asymmetric errors depending on their Hamming weights. The goal of nonuniform codes is to guarantee the reliability of every codeword, which is important in data storage to retrieve whatever one wrote in. We prove an almost explicit upper bound on the size of nonuniform asymmetric error correcting codes and present two general constructions. We also study the rate of nonuniform codes compared to uniform codes and show that there is a potential performance gain.https://authors.library.caltech.edu/records/bk5h1-qa850Systematic Error-Correcting Codes for Rank Modulation
https://resolver.caltech.edu/CaltechAUTHORS:20120828-151501177
Authors: {'items': [{'id': 'Zhou-Hongchao', 'name': {'family': 'Zhou', 'given': 'Hongchao'}}, {'id': 'Jiang-A-A', 'name': {'family': 'Jiang', 'given': 'Anxiao (Andrew)'}}, {'id': 'Bruck-J', 'name': {'family': 'Bruck', 'given': 'Jehoshua'}, 'orcid': '0000-0001-8474-0812'}]}
Year: 2012
DOI: 10.1109/ISIT.2012.6284106
The rank modulation scheme has been proposed recently for efficiently writing and storing data in nonvolatile memories. Error-correcting codes are very important for rank modulation, and they have attracted interest among researchers. In this work, we explore a new approach, systematic error-correcting codes for rank modulation. In an (n,k) systematic code, we use the permutation induced by the levels of n cells to store data, and the permutation induced by the first k cells (k < n) has a one-to-one mapping to information bits. Systematic codes have the benefits of enabling efficient information retrieval and potentially supporting more efficient encoding and decoding procedures. We study systematic codes for rank modulation equipped with the Kendall's τ-distance. We present (k + 2, k) systematic codes for correcting one error, which have optimal sizes unless perfect codes exist. We also study the design of multi-error-correcting codes, and prove that for any 2 ≤ k < n, there always exists an (n, k) systematic code of minimum distance n-k. Furthermore, we prove that for rank modulation, systematic codes achieve the same capacity as general error-correcting codes.https://authors.library.caltech.edu/records/92gz1-39x98Stopping Set Elimination for LDPC Codes
https://resolver.caltech.edu/CaltechAUTHORS:20180125-132316726
Authors: {'items': [{'id': 'Jiang-Anxiao-Andrew', 'name': {'family': 'Jiang', 'given': 'Anxiao (Andrew)'}}, {'id': 'Upadhyaya-P', 'name': {'family': 'Upadhyaya', 'given': 'Pulakesh'}}, {'id': 'Wang-Ying', 'name': {'family': 'Wang', 'given': 'Ying'}}, {'id': 'Narayanan-K-R', 'name': {'family': 'Narayanan', 'given': 'Krishna R.'}}, {'id': 'Zhou-Hongchao', 'name': {'family': 'Zhou', 'given': 'Hongchao'}}, {'id': 'Sima-Jin', 'name': {'family': 'Sima', 'given': 'Jin'}, 'orcid': '0000-0003-4588-9790'}, {'id': 'Bruck-J', 'name': {'family': 'Bruck', 'given': 'Jehoshua'}, 'orcid': '0000-0001-8474-0812'}]}
Year: 2017
DOI: 10.1109/ALLERTON.2017.8262806
This work studies the Stopping-Set Elimination Problem, namely, given a stopping set, how to remove the fewest erasures so that the remaining erasures can be decoded by belief propagation in k iterations (including k =∞). The NP-hardness of the problem is proven. An approximation algorithm is presented for k = 1. And efficient exact algorithms are presented for general k when the stopping sets form trees.https://authors.library.caltech.edu/records/vnf04-m3829