28,636 research outputs found
List decoding of noisy Reed-Muller-like codes
First- and second-order Reed-Muller (RM(1) and RM(2), respectively) codes are
two fundamental error-correcting codes which arise in communication as well as
in probabilistically-checkable proofs and learning. In this paper, we take the
first steps toward extending the quick randomized decoding tools of RM(1) into
the realm of quadratic binary and, equivalently, Z_4 codes. Our main
algorithmic result is an extension of the RM(1) techniques from Goldreich-Levin
and Kushilevitz-Mansour algorithms to the Hankel code, a code between RM(1) and
RM(2). That is, given signal s of length N, we find a list that is a superset
of all Hankel codewords phi with dot product to s at least (1/sqrt(k)) times
the norm of s, in time polynomial in k and log(N). We also give a new and
simple formulation of a known Kerdock code as a subcode of the Hankel code. As
a corollary, we can list-decode Kerdock, too. Also, we get a quick algorithm
for finding a sparse Kerdock approximation. That is, for k small compared with
1/sqrt{N} and for epsilon > 0, we find, in time polynomial in (k
log(N)/epsilon), a k-Kerdock-term approximation s~ to s with Euclidean error at
most the factor (1+epsilon+O(k^2/sqrt{N})) times that of the best such
approximation
Test of a Liquid Argon TPC in a magnetic field and investigation of high temperature superconductors in liquid argon and nitrogen
Tests with cosmic ray muons of a small liquid argon time projection chamber
(LAr TPC) in a magnetic field of 0.55 T are described. No effect of the
magnetic field on the imaging properties were observed. In view of a future
large, magnetized LAr TPC, we investigated the possibility to operate a high
temperature superconducting (HTS) solenoid directly in the LAr of the detector.
The critical current of HTS cables in an external magnetic field was
measured at liquid nitrogen and liquid argon temperatures and a small prototype
HTS solenoid was built and tested.Comment: 5 pages, 5 figures, to appear in Proc. of 1st International Workshop
towards the Giant Liquid Argon Charge Imaging Experiment (GLA2010), Tsukuba
(Japan), March 201
Approximate Sparse Recovery: Optimizing Time and Measurements
An approximate sparse recovery system consists of parameters , an
-by- measurement matrix, , and a decoding algorithm, .
Given a vector, , the system approximates by , which must satisfy , where denotes the optimal -term approximation to . For
each vector , the system must succeed with probability at least 3/4. Among
the goals in designing such systems are minimizing the number of
measurements and the runtime of the decoding algorithm, .
In this paper, we give a system with
measurements--matching a lower bound, up to a constant factor--and decoding
time , matching a lower bound up to factors.
We also consider the encode time (i.e., the time to multiply by ),
the time to update measurements (i.e., the time to multiply by a
1-sparse ), and the robustness and stability of the algorithm (adding noise
before and after the measurements). Our encode and update times are optimal up
to factors
Globalization and National Sovereignty: Controlling the International Food Supply in the Age of Biotechnology
This article examines the biotechnology industry in the area of genetically modified organisms (GMOs) in foods through the lens of globalization and national sovereignty. Does the World Trade Organization (WTO) have the authority to compel the European Union (EU) to lift GMO bans, or should another supranational organization be formed to regulate the world’s food supply as a scientific and policy-making entity? What implications does the WTO’s decision on the food trade dispute have on state sovereignty, nation-state control and regulation of its food supply, and future multilateral environmental and trade agreements? This article discusses GMO’s historic, scientific, and environmental impacts, how globalization and biotechnology have changed the world food supply, and how these developments affect free trade. In addition, this article explores the regulatory reach of organizations such as the WTO, World Health Organization (WHO), and the Food and Agriculture Organization of the United Nations (FAO) on global food security. Finally, this article analyzes the future of the biotechnology industry and GMOs, considering the impact of the WTO’s decisions on developing nations, food labeling, nation- state control and, ultimately, its own credibility
Paterno v. Laser Spine Institute: Did the New York Court of Appeals\u27 Misapplication of Unjustified Policy Fears Lead to A Miscarriage of Justice and the Creation of Inadequate Precedent for the Proper Use of the Empire State’s Long-Arm Statute?
This article discusses CPLR section 302(a)(1) as applied by the New York State Court of Appeals in Paterno v. Laser Spine Institute. The Paterno Court failed to properly apply a statutory jurisdictional analysis by conflating it with a due process inquiry. Also, the Court unnecessarily balanced the interests of the Empire State\u27s citizens in having a forum for access to justice with unjustified policy fears of potential costs to the state from assertions of in personam jurisdiction. Furthermore, the Court\u27s policy focus4 on the protection of medical doctors from lawsuits and the prevention of “floodgate” litigation which would adversely affect the medical profession was not justified by the record and created poor precedent for subsequent judicial application of the state\u27s long-arm statute.
This article will examine CPLR section 302(a)(1), under Paterno v. Laser Spine Institute and some of its predecessors, to demonstrate that sometimes overarching policy concerns get in the way of a strict statutory analysis under CPLR section 302(a)(1). We analyze how the Court of Appeals in Paterno conflated the jurisdictional basis and due process analyses and determine that the Court, based on a faulty statutory analysis, erroneously decided that there was no statutory jurisdiction.
Our article is divided into six parts. Part II briefly discusses the history of the CPLR and the manner of obtaining jurisdiction through Sections 301 and 302, focusing mainly on long-arm jurisdiction. Part III discusses and analyzes leading cases, which involve the application of CPLR 302 in obtaining personal jurisdiction. Part IV discusses a recent case, Paterno v. Laser Spine Institute, in great detail, and Part V engages in a critical analysis of Paterno with reference to a similar case, Grimaldi v. Guinn. Part VI addresses policy considerations and Part VII concludes with a discussion of how the Paterno Court entangled its jurisdictional analysis and where the Court may be headed with its future application of CPLR section 302(a)(1)
Improved sparse approximation over quasi-incoherent dictionaries
This paper discusses a new greedy algorithm for solving the sparse approximation problem over quasi-incoherent dictionaries. These dictionaries consist of waveforms that are uncorrelated "on average," and they provide a natural generalization of incoherent dictionaries. The algorithm provides strong guarantees on the quality of the approximations it produces, unlike most other methods for sparse approximation. Moreover, very efficient implementations are possible via approximate nearest-neighbor data structure
Algorithmic linear dimension reduction in the l_1 norm for sparse vectors
This paper develops a new method for recovering m-sparse signals that is
simultaneously uniform and quick. We present a reconstruction algorithm whose
run time, O(m log^2(m) log^2(d)), is sublinear in the length d of the signal.
The reconstruction error is within a logarithmic factor (in m) of the optimal
m-term approximation error in l_1. In particular, the algorithm recovers
m-sparse signals perfectly and noisy signals are recovered with polylogarithmic
distortion. Our algorithm makes O(m log^2 (d)) measurements, which is within a
logarithmic factor of optimal. We also present a small-space implementation of
the algorithm. These sketching techniques and the corresponding reconstruction
algorithms provide an algorithmic dimension reduction in the l_1 norm. In
particular, vectors of support m in dimension d can be linearly embedded into
O(m log^2 d) dimensions with polylogarithmic distortion. We can reconstruct a
vector from its low-dimensional sketch in time O(m log^2(m) log^2(d)).
Furthermore, this reconstruction is stable and robust under small
perturbations
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