On the binary codes with parameters of triply-shortened 1-perfect codes

We study properties of binary codes with parameters close to the parameters of 1-perfect codes. An arbitrary binary $(n=2^m-3, 2^{n-m-1}, 4)$ code $C$, i.e., a code with parameters of a triply-shortened extended Hamming code, is a cell of an equitable partition of the $n$-cube into six cells. An arbitrary binary $(n=2^m-4, 2^{n-m}, 3)$ code $D$, i.e., a code with parameters of a triply-shortened Hamming code, is a cell of an equitable family (but not a partition) from six cells. As a corollary, the codes $C$ and $D$ are completely semiregular; i.e., the weight distribution of such a code depends only on the minimal and maximal codeword weights and the code parameters. Moreover, if $D$ is self-complementary, then it is completely regular. As an intermediate result, we prove, in terms of distance distributions, a general criterion for a partition of the vertices of a graph (from rather general class of graphs, including the distance-regular graphs) to be equitable. Keywords: 1-perfect code; triply-shortened 1-perfect code; equitable partition; perfect coloring; weight distribution; distance distributionComment: 12 page

EMSO: A Distributed Infrastructure for Addressing Geohazards and Global Ocean Change

Special issue On Undersea Natural Hazards.-- Best, Mairi ... et. al.-- 3 pages, 2 figuresThe European Multidisciplinary Seafloor and water-column Observatory (EMSO; http://www.emso-eu.org) is addressing the next challenge in Earth-ocean science: how to coordinate data acquisition, analysis, archiving, access, and response to geohazards across provincial, national, regional, and international boundaries. Such coordination is needed to optimize the use of current and planned ocean observatory systems to (1) address national and regional public safety concerns about geohazards (e.g., earthquakes, submarine landslides, tsunamis) and (2) permit broadening of their scope toward monitoring environmental change on global ocean scalesEMSO is built on the progress made through over 23 European marine observation projects through many decades. In particular, its foundation is based on the work of hundreds of people in ESONET Concerted Action (FP5) from 2002 to 2004, ESONIM (European Seafoor Observatories Implementation Model) (FP6) from 2004 to 2007, ESONET-NoE (FP6) from 2007 to 2011, and EMSO-Preparatory Phase (FP7) from 2008–2012Peer Reviewe

A sharpened version of the aanderaa-rosenberg conjecture

Wetensch. publicatieFaculteit der Wiskunde en Natuurwetenschappe

Understanding Earth– Ocean Processes using Real-time Data from NEPTUNE, Canada’s Widely Distributed Sensor Networks, Northeast Pacific

After several years of planning, NEPTUNE Canada [www.neptunecanada.ca], as part of the Ocean Networks Canada Observatory, largely completed the installation of the world’s first regional cabled observatory network in 2009. The 800 km cable loop west of Vancouver Island connects five nodes in coastal, continental slope, abyssal plain and spreading-ridge environments. Abundant power and high-bandwidth communications support a network of hundreds of sensors that deliver data and imagery in real- or near real-time, and will transform our knowledge of the ocean environment and interacting processes. With the world’s oceans and climate in a state of crisis, the development of cabled observatory technologies is most timely and offers a growing data archive of unparalleled importance for new discoveries. Sommaire Apres plusieurs années de planification, l’essentiel du premier reseau observatoire régional, NEPTUNE Canada [www.neptunecanada.ca], partie intégrante du Ocean Network Observatory, a été installé en 2009. Ses 800km de cable forment une boucle à l’ Ouest de l’ Isle de Vancouver et sont connectés à cinq noeuds situés au niveau de la zone cotière, du talus continental, de la plaine abyssale et de la dorsale océanique. Grace à cet acces à l’ énergie et la communication à haut débit, un réseau de centaines de capteurs transmettent des données et images en temps réel ou quasi réel, qui transformeront nos connaissances du mileu et processus océaniques. Alors que les océans et le climat sont en état de stress, le dévelopment des technologies liées aux observatoires sous marins représente une opportunité exceptionelle et un recueil de données sans cesse croissant et d’ un potentiel inégalé pour permettre de nouvelles découvertes

5 year-long monitoring of Barkley Canyon cold-seeps with the internet operated deep-sea crawler "Wally"

Despite the technological advances of the last decades (e.g. ROVs, AUVs, cabled observatories), our knowledge of most deep-sea environments is still strongly limited by spatio-temporal sampling and observational capabilities. The novel Internet Operated Deep-Sea Crawler technology can provide high-frequency, multi-sensor data, during long-term deployments, 24/7 communication with researchers and broader spatial coverage (i.e. mobile platform) than fixed instrument installations. The crawler “Wally” is deployed at the Barkley Canyon methane hydrates site (NE Pacific, Canada; ~890 m depth) and connected to the Ocean Networks Canada NEPTUNE cabled observatory network (ONC; www. oceannetworks.ca). Here we present the environmental and biological datasets obtained from Wally instruments and cameras, during the first deployment phase (September 2010 to January 2015), as well as new features and preliminary results obtained since it was re-deployed (May 2016 – present). In addition to data provided by the standard payload of the crawler (i.e. ADCP, CTD, methane sensor, turbidity sensor and fluorometer), the hydrates community was video-monitored at different frequencies and timespans. Photomosaics were generated at two distinct locations, in order to map chemosynthetic bacterial mats and vesicomyid clam colonies covering the ~2-3 m high hydrate mounds, and document their temporal dynamics. The crawler followed the development of a deep-sea shell taphonomic experiment aiming to quantify biogenic carbon fluxes at the hydrates environment. The composition and diel activity patterns of the hydrates megafaunal community were studied with the use of linear video-transects conducted from February 2013 to April 2014. Since the summer of 2016, video-frames recorded at different locations of the site are analyzed for a biodiversity study and photomosaicing of the hydrate mounds continues, with 3D modelling of the mound structures also available as a new feature of the crawler deployed in May 2016. All data are archived in real-time and can be accessed online on the Ocean Networks Canada database. As deep-sea crawler technology and similar mobile, benthic platform technologies progress towards full operational autonomy, they will provide an even greater capacity for future monitoring and understanding of dynamic, extreme environments such as methane hydrate fields.Peer Reviewe

Two Optimal One-Error-Correcting Codes of Length 13 That Are Not Doubly Shortened Perfect Codes

The doubly shortened perfect codes of length 13 are classified utilizing the classification of perfect codes in [P.R.J. \"Osterg{\aa}rd and O. Pottonen, The perfect binary one-error-correcting codes of length 15: Part I - Classification, IEEE Trans. Inform. Theory, to appear]; there are 117821 such (13,512,3) codes. By applying a switching operation to those codes, two more (13,512,3) codes are obtained, which are then not doubly shortened perfect codes.Comment: v2: a correction concerning shortened codes of length 1