White paper: A plan for cooperation between NASA and DARPA to establish a center for advanced architectures

Large, complex computer systems require many years of development. It is recognized that large scale systems are unlikely to be delivered in useful condition unless users are intimately involved throughout the design process. A mechanism is described that will involve users in the design of advanced computing systems and will accelerate the insertion of new systems into scientific research. This mechanism is embodied in a facility called the Center for Advanced Architectures (CAA). CAA would be a division of RIACS (Research Institute for Advanced Computer Science) and would receive its technical direction from a Scientific Advisory Board established by RIACS. The CAA described here is a possible implementation of a center envisaged in a proposed cooperation between NASA and DARPA

The Emergence of Miller's Magic Number on a Sparse Distributed Memory

Human memory is limited in the number of items held in one's mind—a limit known as “Miller's magic number”. We study the emergence of such limits as a result of the statistics of large bitvectors used to represent items in memory, given two postulates: i) the Sparse Distributed Memory; and ii) chunking through averaging. Potential implications for theoretical neuroscience are discussed

Geometric Algebra Model of Distributed Representations

Formalism based on GA is an alternative to distributed representation models developed so far --- Smolensky's tensor product, Holographic Reduced Representations (HRR) and Binary Spatter Code (BSC). Convolutions are replaced by geometric products, interpretable in terms of geometry which seems to be the most natural language for visualization of higher concepts. This paper recalls the main ideas behind the GA model and investigates recognition test results using both inner product and a clipped version of matrix representation. The influence of accidental blade equality on recognition is also studied. Finally, the efficiency of the GA model is compared to that of previously developed models.Comment: 30 pages, 19 figure

Incremental dimension reduction of tensors with random index

We present an incremental, scalable and efficient dimension reduction technique for tensors that is based on sparse random linear coding. Data is stored in a compactified representation with fixed size, which makes memory requirements low and predictable. Component encoding and decoding are performed on-line without computationally expensive re-analysis of the data set. The range of tensor indices can be extended dynamically without modifying the component representation. This idea originates from a mathematical model of semantic memory and a method known as random indexing in natural language processing. We generalize the random-indexing algorithm to tensors and present signal-to-noise-ratio simulations for representations of vectors and matrices. We present also a mathematical analysis of the approximate orthogonality of high-dimensional ternary vectors, which is a property that underpins this and other similar random-coding approaches to dimension reduction. To further demonstrate the properties of random indexing we present results of a synonym identification task. The method presented here has some similarities with random projection and Tucker decomposition, but it performs well at high dimensionality only (n>10^3). Random indexing is useful for a range of complex practical problems, e.g., in natural language processing, data mining, pattern recognition, event detection, graph searching and search engines. Prototype software is provided. It supports encoding and decoding of tensors of order >= 1 in a unified framework, i.e., vectors, matrices and higher order tensors.Comment: 36 pages, 9 figure

Mitä voimme oppia maailmalla järjestetyistä perusturvaan liittyvistä kokeista? : Katsaus kenttäkoeasetelmiin

Tämän työpaperin tarkoituksena on esitellä ulkomailla tehtyjä tai suunnitteilla olevia perustulokokeita, jotka voivat olla hyödyksi Suomessa vireillä olevan perustulokokeilun valmistelu-työssä. Kuvailemme myös muita kenttäkokeita, joiden koeasetelmista voidaan Suomessakin ottaa oppia. Käymme lisäksi läpi perustulokokeiden vaikutusten arvioimisen kannalta keskeistä taloustieteellistä teoriaa. Lähteinä olemme käyttäneet akateemisia tutkimusjulkaisuja. Tämä on rajannut tarkastelusta pois kokeet tai kokeilut, joista ei ole tehty kunnollisia selvityksiä tai analyysejä. Alankomaissa suunnitteilla olevien kokeiden tiedot perustuvat niitä valmistelevien tutkijoiden haastatteluihin. Kuvailemme työpaperissa lyhyesti, minkälaisia eri kokeet ovat olleet ja minkälaisia tuloksia niistä on saatu. Näihin havaintoihin perustuen olemme valmistelleet listan keskeisimmistä opeista, jotka kannattaa huomioida suomalaisen perustulokenttäkokeen valmistelussa. Nämä opit on jaettu kolmeen aihealueeseen: tutkimuskysymykset, koeasetelma ja tulosten arvioiminen. Yksi olennaisimmista tutkimuskysymyksistä perustulokokeessa on selvittää, miten ilman tiukkoja ehtoja ja tulorajoja myönnettävä rahaetuus vaikuttaa työn tarjontaan. Sitä olisi hyvä tutkia erilaisilla perustulotason ja veroasteiden yhdistelmillä, jotta voidaan ymmärtää sekä tulo- että substituutiovaikutuksia. Subjektiivisen hyvinvoinnin ja stressitasojen mittaaminen voi auttaa havaitsemaan perustulon vaikutuksia herkemmin ja yksilöllisemmin kuin pelkän työn tarjonnan tarkastelu. Siksi myös niitä tulisi seurata kokeessa. Laadullisesti hyvän koeasetelman edellytyksenä on riittävän iso otoskoko, joka mahdollistaa eri ihmisryhmien tarkemman tarkastelun. Koehenkilöt tulee valita arpomalla ja vapaaehtoisten käyttöä koehenkilöinä tulisi välttää. Koska tietylle alueelle rajautuva koe vähentää tulosten yleistettävyyttä, olisi valtakunnallinen koe suotuisin vaihtoehto. Kokeen on kestettävä myös riittävän pitkään, jotta käyttäytymisvaikutuksia ehditään havaita. Tulosten arviointiin liittyen suosittelemme, että kokeiltavan ohjelman arviointi otetaan huomioon jo suunnittelu- ja toteutusvaiheessa. Tuloksia arvioitaessa oikean ajankohdan valitseminen aineistosta on yhtä lailla tärkeää. Lisäksi kokeen aineiston avoimuus parantaa tutkimuksen laatua. Mikään aiemmin suoritetuista perustulokokeista ei pysty antamaan suoraan vastauksia, miten perustulon käyttöönotto vaikuttaisi ihmisten käyttäytymiseen Suomessa, koska ne on tehty Suomen nykytilasta poikkeavissa olosuhteissa. Muista kokeista voidaan kuitenkin ammentaa ideoita siihen, miten perustulokokeilu Suomessa kannattaisi toteuttaa

Metal and metalloid exposure and oxidative status in free-living individuals of Myotis daubentonii

Metal elements, ubiquitous in the environment, can cause negative effects in long-lived organisms even after low but prolonged exposure. Insectivorous bats living near metal emission sources can be vulnerable to such contaminants. Although it is known that bats can bioaccumulate metals, little information exists on the effects of metal elements on their physiological status. For example, oxidative status markers are known to vary after detoxification processes and immune reactions. Here, for two consecutive summers, we sampled individuals from a natural population of the insectivorous bat, Myotis daubentonii, inhabiting a site close to a metal emission source. We quantified metals and metalloids (As, Ca, Cd, Co, Cu, Mn, Ni, Pb, Se, Zn) from individual fecal pellets. We measured enzymatic antioxidants (GP, CAT, SOD), total glutathione (tGSH) and ratio between reduced and oxidized glutathione (GSH:GSSG) from their red blood cells together with biometrics, hematocrit and parasite prevalence. In general, metal concentrations in feces of M. daubentonii reflected the exposure to ambient contamination. This was especially evident in the higher concentrations of Cd, Co, Cu and Ni close to a smelter compared to a site with less contaminant exposure. Annual differences were also observed for most elements quantified. Sex-specific differences were observed for calcium and zinc excretion. SOD and CAT enzymatic activities were associated with metal levels (principal components of six metal elements), suggesting early signs of chronic stress in bats. The study also shows promise for the use of non-invasive sampling to assess the metal exposure on an individual basis and metal contamination in the environment.Peer reviewe

Different relationship between hsp70 mRNA and hsp70 levels in the heat shock response of two salmonids with dissimilar temperature preference

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Cartoon Computation: Quantum-like computing without quantum mechanics

We present a computational framework based on geometric structures. No quantum mechanics is involved, and yet the algorithms perform tasks analogous to quantum computation. Tensor products and entangled states are not needed -- they are replaced by sets of basic shapes. To test the formalism we solve in geometric terms the Deutsch-Jozsa problem, historically the first example that demonstrated the potential power of quantum computation. Each step of the algorithm has a clear geometric interpetation and allows for a cartoon representation.Comment: version accepted in J. Phys.A (Letter to the Editor

ORP2 couples LDL-cholesterol transport to FAK activation by endosomal cholesterol/PI(4,5)P-2 exchange

Low-density lipoprotein (LDL)-cholesterol delivery from late endosomes to the plasma membrane regulates focal adhesion dynamics and cell migration, but the mechanisms controlling it are poorly characterized. Here, we employed auxin-inducible rapid degradation of oxysterol-binding protein-related protein 2 (ORP2/OSBPL2) to show that endogenous ORP2 mediates the transfer of LDL-derived cholesterol from late endosomes to focal adhesion kinase (FAK)-/integrin-positive recycling endosomes in human cells. In vitro, cholesterol enhances membrane association of FAK to PI(4,5)P-2-containing lipid bilayers. In cells, ORP2 stimulates FAK activation and PI(4,5)P-2 generation in endomembranes, enhancing cell adhesion. Moreover, ORP2 increases PI(4,5)P-2 in NPC1-containing late endosomes in a FAK-dependent manner, controlling their tubulovesicular trafficking. Together, these results provide evidence that ORP2 controls FAK activation and LDL-cholesterol plasma membrane delivery by promoting bidirectional cholesterol/PI(4,5)P-2 exchange between late and recycling endosomes.Peer reviewe