Händelser: Data- och informationsteknikhttp://www.chalmers.se/sv/om-chalmers/kalendariumAktuella händelser på Chalmers tekniska högskolaWed, 17 Jan 2018 08:08:21 +0100http://www.chalmers.se/sv/om-chalmers/kalendariumhttps://www.chalmers.se/sv/institutioner/cse/kalendarium/Sidor/Thesis-Defence-Bapi-Chatterjee.aspxhttps://www.chalmers.se/sv/institutioner/cse/kalendarium/Sidor/Thesis-Defence-Bapi-Chatterjee.aspxBapi Chatterjee, Data- och informationsteknik<p>EA, lecture hall, EDIT trappa C, D och H, EDIT</p><p>​Lock-free Concurrent Search</p><img src="/SiteCollectionImages/Institutioner/DoIT/Profile%20pictures/NS/Bapi.png" class="chalmersPosition-FloatRight" alt="" style="margin:5px" />The contemporary computers typically consist of multiple computing cores with high compute power. Such computers make excellent concurrent asynchronous shared memory system. On the other hand, though many celebrated books on data structure and algorithm provide a comprehensive study of sequential search data structures, unfortunately, we do not have such a luxury if concurrency comes in the setting. The present dissertation aims to address this paucity. We describe novel lock-free algorithms for concurrent data structures that target a variety of search problems.<p></p> <br /><ol><li>Point search (membership query, predecessor query, nearest neighbour query) for 1-dimensional data: Lock-free linked-list; lock-free internal and external binary search trees (BST). </li> <li>Range search for 1-dimensional data: A range search method for lock-free ordered set data structures - linked-list, skip-list and BST. </li> <li>Point search for multi-dimensional data: Lock-free kD-tree, specially, a generic method for nearest neighbour search.</li></ol> We prove that the presented algorithms are linearizable i.e. the concurrent data structure operations intuitively display their sequential behaviour to an observer of the concurrent system. The lock-freedom in the introduced algorithms guarantee overall progress in an asynchronous shared memory system. We present the amortized analysis of lock-free data structures to show their efficiency. Moreover, we provide sample implementations of the algorithms and test them over extensive micro-benchmarks. Our experiments demonstrate that the implementations are scalable and perform well when compared to related existing alternative implementations on common multi-core computers.<p></p> <br /> Our focus is on propounding the generic methodologies for efficient lock-free concurrent search. In this direction, we present the notion of help-optimality, which captures the optimization of amortized step complexity of the operations. In addition to that, we explore the language-portable design of lock-free data structures that aims to simplify an implementation from programmer’s point of view. Finally, our techniques to implement lock-free linearizable range search and nearest neighbour search are independent of the underlying data structures and thus are adaptive to similar data structures.<br />https://www.chalmers.se/sv/institutioner/cse/kalendarium/Sidor/Licentiate-seminar-Christoffer-Fougstedt.aspxhttps://www.chalmers.se/sv/institutioner/cse/kalendarium/Sidor/Licentiate-seminar-Christoffer-Fougstedt.aspxChristoffer Fougstedt, Data- och informationsteknik<p>EA, lecture hall, EDIT trappa C, D och H, EDIT</p><p>​High-throughput power-efficient DSP for fiber-optic communication systems</p>https://www.chalmers.se/sv/institutioner/cse/kalendarium/Sidor/Thesis-Defence-Iosif-Salem.aspxhttps://www.chalmers.se/sv/institutioner/cse/kalendarium/Sidor/Thesis-Defence-Iosif-Salem.aspxIosif Salem, Data- och informationsteknik<p>SB-H5, lecture hall, Arkitektur, Campus Johanneberg</p><p>​Shared Resources in Distributed Systems: Analytical Tools for Evaluation and Self-stabilizing Provisioning</p><img src="/SiteCollectionImages/Institutioner/DoIT/Profile%20pictures/NS/Iosif.jpg" class="chalmersPosition-FloatRight" alt="" style="margin:5px" />Distributed computing is an established computing paradigm of modern computing systems.The nodes of a distributed system interact either by sharing resources or via a communication network. In both cases, provisioning of shared resources is a challenge, for example when resource demand and supply varies or when the system is prone to failures. Analytical tools for evaluating system performance and for provisioning shared resources enhance system design and implementations.<p></p> <br /> In this thesis, we develop analytical tools for the evaluation and self-stabilizing provisioning of shared-resources in distributed systems. We first focus on systems where resource demand and supply varies, and study cases of reusable and non-reusable resources. We study shared-object systems, where system nodes demand mutually exclusive access to a number of objects in a continuous fashion. We develop analytical tools for computing the expected delay and throughput of such systems, in a wide range of system utilization scenarios, including saturation points. Moreover, we study systems where nodes share energy resources, and focus on optimizing the available resources on a system-level. We develop online algorithms that use the flexibility on resource demand, to optimize the utilization of the available supply, and prove their competitive ratios.<p></p> <br /> Recovery from failures is necessary for provisioning shared resources. Dynamic and complex systems are often designed based on a failure model, but it is important that they recover even after the occurrence of unexpected failures, outside the failure model. Such failures can include topological changes in the network, stale information in the nodes' memory, communication failures, etc. These failures are further amplified by the system's asynchrony. In these settings, we first focus on provisioning of network resources, in terms of network control and ordering of distributed events. We study Software-Defined Networks (SDNs) and specifically their control planes. We provide a self-stabilizing distributed algorithm for a fault-tolerant SDN control plane, that deals with communication failures, topological changes, as well as, with transient faults, that can bring the system in an arbitrary state. Moreover, we focus on ordering distributed events in asynchronous message-passing systems, in the absence of execution fairness. In these extreme asynchronous settings, we provide a practically-self-stabilizing distributed algorithm, that uses bounded memory and yet, can tolerate concurrent counter overflows, when counting distributed events, as well as transient faults.<p></p> <br />https://www.chalmers.se/sv/styrkeomraden/ikt/kalendarium/Sidor/Seminarium-5G-and-Over-the-Air-Testing.aspxhttps://www.chalmers.se/sv/styrkeomraden/ikt/kalendarium/Sidor/Seminarium-5G-and-Over-the-Air-Testing.aspxSeminarium 5G and Over the Air Testing<p>Provinn, Kvarnbergsgatan 2, Göteborg</p><p>​Microwave road välkomnar Chalmersanställda och studenter till ett spännande seminarium om 5G och over the air testing.</p>​<span class="text-normal page-content"> <br />PROGRAM<br />16.00 –16.30 Registration and Coffee<br />16.30–16.40 Introduction of MWR<br />16.40–17.00 Mats Högberg, Huawei ”5G and why do we need Over The Air requirements”<br />17.00–17.30 Wei Fan, Aalborg University “Over-the-air radiated performance testing of 5G radios”<br />17.30–17.40 Coffee break<br />17.40–18.10 Bengt Svensson, Saab “Antenna measurement challenges at Saab”<br />18.10–18.40 Klas Arvidsson, Bluetest ”OTA Reverberation chamber opportunities”<br />18.40–19.10 Madeleine Schilliger Kildal, Chalmers &amp; RanLOS<br />”The Random-LOS Measurement System for Vehicular Communication”<br />19.10 –21.00 Beverage, food and continuation with Over The Air discussions<br /><br /><br /><strong>R.S.V.P: 24th january 2018<span style="display:inline-block"></span></strong><br />Registration: <a href="mailto:mats.hogberg@huawei.com">mats.hogberg@huawei.com</a><br />Parking: Nordstan or The Opera House<br /><br />Microwave Road, <span><a href="https://www.microwaveroad.se/" target="_blank">www.microwaveroad.se</a></span></span>https://www.chalmers.se/sv/institutioner/cse/kalendarium/Sidor/Thesis-Defence-Thomas-Petig.aspxhttps://www.chalmers.se/sv/institutioner/cse/kalendarium/Sidor/Thesis-Defence-Thomas-Petig.aspxThomas Petig, Data- och informationsteknik<p>EA, lecture hall, EDIT trappa C, D och H, EDIT</p><p>​Topics in Distributed Algorithms: On Wireless Networks, Distributed Storage and Streaming</p>https://www.chalmers.se/sv/styrkeomraden/ikt/kalendarium/Sidor/Initiative-Seminar-2018-Digitalisation.aspxhttps://www.chalmers.se/sv/styrkeomraden/ikt/kalendarium/Sidor/Initiative-Seminar-2018-Digitalisation.aspxInitiativseminarium om Digitalisering - Säkerhet och integritet | Maskinintelligens<p>RunAn, conference hall, Kårhuset, Campus Johanneberg</p><p>​Välkommen till Chalmers konferenscenter, Runan, den 15 mars 2018.</p>​ <br /><span class="text-normal page-content"><span>Det välbesökta initiativseminariet om Digitalisering 2017 får nu en uppföljare. Den här gången presenterar vi ett mer inriktat program – en halvdag om maskinintelligens och en halvdag om säkerhet and integritet.<br /><br /><a href="/en/areas-of-advance/ict/events/Digitalisation2018/Pages/default.aspx">Mer information finns på initiativseminariets webbsida &gt;</a></span></span>