I/O-Efficient Dynamic Planar Range Skyline Queries

We present the first fully dynamic worst case I/O-efficient data structures that support planar orthogonal \textit{3-sided range skyline reporting queries} in \bigO (\log_{2B^\epsilon} n + \frac{t}{B^{1-\epsilon}}) I/Os and updates in \bigO (\log_{2B^\epsilon} n) I/Os, using \bigO (\frac{n}{B^{1-\epsilon}}) blocks of space, for $n$ input planar points, $t$ reported points, and parameter $0 \leq \epsilon \leq 1$. We obtain the result by extending Sundar's priority queues with attrition to support the operations \textsc{DeleteMin} and \textsc{CatenateAndAttrite} in \bigO (1) worst case I/Os, and in \bigO(1/B) amortized I/Os given that a constant number of blocks is already loaded in main memory. Finally, we show that any pointer-based static data structure that supports \textit{dominated maxima reporting queries}, namely the difficult special case of 4-sided skyline queries, in \bigO(\log^{\bigO(1)}n +t) worst case time must occupy $\Omega(n \frac{\log n}{\log \log n})$ space, by adapting a similar lower bounding argument for planar 4-sided range reporting queries.Comment: Submitted to SODA 201

Harvesting Multiple Views for Marker-less 3D Human Pose Annotations

Recent advances with Convolutional Networks (ConvNets) have shifted the bottleneck for many computer vision tasks to annotated data collection. In this paper, we present a geometry-driven approach to automatically collect annotations for human pose prediction tasks. Starting from a generic ConvNet for 2D human pose, and assuming a multi-view setup, we describe an automatic way to collect accurate 3D human pose annotations. We capitalize on constraints offered by the 3D geometry of the camera setup and the 3D structure of the human body to probabilistically combine per view 2D ConvNet predictions into a globally optimal 3D pose. This 3D pose is used as the basis for harvesting annotations. The benefit of the annotations produced automatically with our approach is demonstrated in two challenging settings: (i) fine-tuning a generic ConvNet-based 2D pose predictor to capture the discriminative aspects of a subject's appearance (i.e.,"personalization"), and (ii) training a ConvNet from scratch for single view 3D human pose prediction without leveraging 3D pose groundtruth. The proposed multi-view pose estimator achieves state-of-the-art results on standard benchmarks, demonstrating the effectiveness of our method in exploiting the available multi-view information.Comment: CVPR 2017 Camera Read

I/O-Efficient Planar Range Skyline and Attrition Priority Queues

In the planar range skyline reporting problem, we store a set P of n 2D points in a structure such that, given a query rectangle Q = [a_1, a_2] x [b_1, b_2], the maxima (a.k.a. skyline) of P \cap Q can be reported efficiently. The query is 3-sided if an edge of Q is grounded, giving rise to two variants: top-open (b_2 = \infty) and left-open (a_1 = -\infty) queries. All our results are in external memory under the O(n/B) space budget, for both the static and dynamic settings: * For static P, we give structures that answer top-open queries in O(log_B n + k/B), O(loglog_B U + k/B), and O(1 + k/B) I/Os when the universe is R^2, a U x U grid, and a rank space grid [O(n)]^2, respectively (where k is the number of reported points). The query complexity is optimal in all cases. * We show that the left-open case is harder, such that any linear-size structure must incur \Omega((n/B)^e + k/B) I/Os for a query. We show that this case is as difficult as the general 4-sided queries, for which we give a static structure with the optimal query cost O((n/B)^e + k/B). * We give a dynamic structure that supports top-open queries in O(log_2B^e (n/B) + k/B^1-e) I/Os, and updates in O(log_2B^e (n/B)) I/Os, for any e satisfying 0 \le e \le 1. This leads to a dynamic structure for 4-sided queries with optimal query cost O((n/B)^e + k/B), and amortized update cost O(log (n/B)). As a contribution of independent interest, we propose an I/O-efficient version of the fundamental structure priority queue with attrition (PQA). Our PQA supports FindMin, DeleteMin, and InsertAndAttrite all in O(1) worst case I/Os, and O(1/B) amortized I/Os per operation. We also add the new CatenateAndAttrite operation that catenates two PQAs in O(1) worst case and O(1/B) amortized I/Os. This operation is a non-trivial extension to the classic PQA of Sundar, even in internal memory.Comment: Appeared at PODS 2013, New York, 19 pages, 10 figures. arXiv admin note: text overlap with arXiv:1208.4511, arXiv:1207.234

Homomorphically encrypted gradient descent algorithms for quadratic programming

In this paper, we evaluate the different fully homomorphic encryption schemes, propose an implementation, and numerically analyze the applicability of gradient descent algorithms to solve quadratic programming in a homomorphic encryption setup. The limit on the multiplication depth of homomorphic encryption circuits is a major challenge for iterative procedures such as gradient descent algorithms. Our analysis not only quantifies these limitations on prototype examples, thus serving as a benchmark for future investigations, but also highlights additional trade-offs like the ones pertaining the choice of gradient descent or accelerated gradient descent methods, opening the road for the use of homomorphic encryption techniques in iterative procedures widely used in optimization based control. In addition, we argue that, among the available homomorphic encryption schemes, the one adopted in this work, namely CKKS, is the only suitable scheme for implementing gradient descent algorithms. The choice of the appropriate step size is crucial to the convergence of the procedure. The paper shows firsthand the feasibility of homomorphically encrypted gradient descent algorithms

The north-south divide, the Euro and the world

The European north-south divide has been an issue of a long-standing debate. We employ a Global VAR model for 28 developed and developing countries to examine the interaction between the global trade imbalances and their impact within the euro-area framework. The aim is to assess the propagation mechanisms of real shocks, focusing on the interconnections among the north euro area and the south euro area. We incorporate theory-based long-run over-identifying restrictions and examine the effects of (i) nonexport real output shocks, (ii) expansionary shocks and (iii) real exchange rate shocks. An expansionary policy of the north euro area and increased competitiveness in the south euro area could alleviate trade imbalances of the debtor euro area economies. From the south euro area perspective, internal devaluation decreases output but at the same time, it also reduces current account deficits. North euro area origin shocks to domestic output exert a dominant influence in the rest of the Europe and Asi

Use of twitter and Facebook by top European museums

With social media becoming so pervasive, museums strive to adopt them for their own use. Effective use of social media especially Facebook and Twitter seems to be promising. Social media offer museums the possibility to engage audiences, potential and active visitors with their collections and ideas. Facebook and Twitter are the market leaders of social media. This paper records the top European museums and their Facebook and Twitter accounts. It records the use of the two media, and by applying statistical analysis it investigates whether Twitter use is in accordance to Facebook use. Findings reveal that this is not the case. By using Principal Component Analysis and Cluster Analysis the paper finds that there is, however, a district group of top museums which manage to excel in both media mainly by adopting carefully planned strategies and paying attention to the potential and benefits that social media offer

Hannah Arendtin toiminnan teoria ja käsitys työn merkityksestä neljännen teollisen vallankumouksen kontekstissa

Hannah Arendtin toiminnan teorian käsitteellisiä resursseja hyödyntäen voi pohtia inhimillisen toiminnan mahdollisuuksia ja ehdollistuneisuutta nykyisessä automaation historiallisessa kontekstissa. Neljännen teollisen vallankumouksen myötä on mahdollista automatisoida kognitiivisia ja affektiivisia työtehtäviä. Taloustieteen perspektiivistä tämä tarkoittaa teollisen tuotannon muuntumista yhä teknologiakeskeisemmäksi. Samanaikaisesti modernina teollisena aikana työ on noussut keskeisimmäksi yksilön yhteisöllistä toimintaa määritteleväksi tekijäksi, joka määrää niin yksilön sosioekonomista asemaa kuin identiteetin muodostamisen tilaa. Tämä yhtälö on nostanut automaatioahdistusta yksilö- ja yhteisötasolla. Tämän tutkielman tarkoituksena on hahmotella ja analysoida Arendtin käsitystä työn ilmiöstä ja luonteesta nykyteknologian kontekstissa, kun tarkastellaan nimenomaan syväoppivien algoritmien vaikutusta työn organisointiin. Neljännen teollisen vallankumouksen ilmiötä analysoidaan teoreettisesti Hannah Arendtin poliittisen ajattelun ja työn merkityksen fenomenologisen analyysin näkökulmasta. Käsitteellisenä lähtökohtana toimii Arendtin jaottelu työhön, valmistamiseen ja toimintaan sekä hänen tilallinen erottelunsa yksityiseen, sosiaaliseen ja julkiseen alueeseen. Arendtin ajattelua työstä on käsitelty kriittisesti. Kritiikin mukaan Arendtin ajattelun ei nähdä soveltuvan nykyiseen keskusteluun työstä ja yhteiskunnasta. Tutkielmassa väitetään Arendtin olevan edelleen ajankohtainen ajattelija työn institutionaalisen merkityksen analyysissä. Arendtin teoksia käytetään empiirisenä pohjana pohdinnoille inhimillisen toiminnan tilasta nykyisessä maailmassa. Nykyhetkellä vain yhteiskuntiemme keskeisimpien käsitteiden, kuten työn ja vapauden, institutionaalisessa tarkastelussa on mahdollista löytää yhteiskunnallisista muutoksista ja ilmiöistä emansipatorisia kulkusuuntia. Arendtin antropologisen lähestymistavan avulla on mahdollista syvällisesti tutkia inhimillisen toiminnan mahdollisuuksia nykyautomaation kontekstissa. Automaation merkitys Arendtin ajattelussa on ollut tutkimusten marginaalissa siitä huolimatta, että automaatiolla on huomattava vaikutus Arendtin ajatteluun. Tutkielman tilallinen analyysi osoittaa Arendtin vievän työn ilmiön tutkimisen institutionaaliselle tasolle. Näin ollen Arendtia tulkitaan työn olemassaolon ehtojen teoreetikkona. Työn tilallisia ehtoja ovat materiaalisuus, uniikkiuden mahdollistaminen ja maailmallisuus. Nämä työn tilalliset merkitykset syntyvät yksilölle kolmen ulottuvuuden kautta, joita ovat työ paikan ottamisena, aseman omistamisena ja kannanottamisena. Työn tilallisen analyysin kautta on mahdollista arvioida työn yhteisöllistä ja poliittista merkityksellisyyttä. Nykykontekstissa työn merkitys yksilötasolla on sallia jokaiselle yksilölle mahdollisuus julkiseen tilaan. Automaation ja vapauden välisen suhteen analyysin mukaan Arendtin toiminnan teoria tarjoaa resursseja analysoida inhimillistä ehdollistuneisuutta ja institutionaalisen vapauden mahdollisuutta nykyisessä historiallisessa kontekstissa. Näin edistetään kuvaa Arendtista automaation ajattelijana. Arendtilaisesta näkökannasta katsottuna automaation tarkoitus on toimia neutraalina institutionaalisen vapauden mahdollistajana. Arendt ei näe uusia teknologioita, kuten palvelurobotteja, uhkana ihmisten väliselle toiminnalle. Arendtin mukaan vain inhimillinen ajattelu, erotettuna kognitiosta ja loogisesta päättelykyvystä, voi toimia historiallisuuden, merkityksen ja inhimillisen olemassaolon kirkastajana. Ajattelua vaativien töiden tehtävänä on auttaa yhteiskuntajärjestelmää maailmallisuuden ja kestävyyden ylläpitämisessä maailmassa, jossa tekoäly ja automaatio toimivat yhteiskunnan organisatorisen rationaalisuuden pohjana.Hannah Arendt’s theory of action acts as a conceptual resource to ponder human action and conditionality in the current historical context of automation. With the fourth industrial revolution, it is plausible to automate jobs that require cognitive and affective skills. From an economic perspective this means that production is becoming more techonlogy-centered. Simultaneously work has become the main source for individual’s societal action, which determines individual’s socioeconomic position as well as the space for identity formation. This equation has raised automation anxiety in an individual and societal level. The purpose of this thesis is to outline and analyze Arendt’s conception of work in the context of present technologies, more specifically, when studying the impact of deep learning algorithms to organization of work. I am analyzing the phenomenon of fourth industrial revolution theoretically through Arendt’s political thought through phenomenological analysis of meaning of work. Arendt’s concepts of labor, work and action and her distinctions of private, social and private realms act as a conceptual premise. Arendt’s thought on work has been examined critically. According to the critique, Arendt’s thinking on work and society is not suitable for contemporary social analysis. In this thesis, I claim that Arendt is still a timely thinker regarding the institutional meaning of work. Arendt’s writings act as an empirical basis to analyze the state of human action in the current era. Only by analyzing the most fundamental concepts of our society, work and freedom, it is possible to find emancipatory directions in societal transformations. With the support of Arendt’s anthropological approach, we are able to deeply explore possibilities for human action in the context of today’s automation. The significance of automation in Arendt’s thought has attracted marginal attention despite its relevance in her views on human state of affairs. The spatial analysis in this thesis points that Arendt takes her thinking on work on an institutional level. Thus, Arendt can be interpreted as a theorist of conditions for existence of work. Work’s spatial conditions are materiality, uniqueness and worldliness. These spatial meanings of work are formed through three dimensions, which are work as taking a place, as having a position and as taking a stand. Through spatial analysis of work it is conceivable to evaluate political and communal significance of work. In our current context, the meaning of work is to permit a space for an individual to form a public space through work. In this thesis, relationship between automation and freedom is analyzed through Arendt’s theory of action, which offers resources to study human conditionality and institutional freedom in our current historical context. In this way Arendt is fostered as a thinker of automation. From an arendtian perspective, the purpose of automation is to act as a neutral enabler of institutional freedom. Arendt does not regard new technologies, like service robots, as threats for human action. According to Arendt, only human thinking, as separated from cognition and logical reasoning ability, can function as nurturers of historicity, meaning and human existence. The task of human thinking is to work and support the worldliness and durability of the social system in a world where artificial intelligence and automation operate as the basis of society’s organizational rationality