A conflict-free memory banking architecture for fast VOQ packet buffers

In order to support the enormous growth of the Internet, innovative research in every router subsystem is needed. We focus our attention on packet buffer design for routers supporting high-speed line rates. More specifically, we address the design of packet buffers using virtual output queuing (VOQ), which are used in most modern router architectures. The design is based on a previously proposed scheme that uses a combination of SRAM and DRAM modules. We propose a storage scheme that achieves a conflict-free memory bank organization. This leads to a reduction of the granularity of DRAM accesses, resulting in a decrease of storage capacity needed by the SRAM. In the DRAM/SRAM scheme, SRAM memory bandwidth needs to fit the line rate. Since memory bandwidth is limited by its size, searching for memory schemes having a small SRAM size arises as an essential issue for high speed line rates (e.g. OC768, 40 Gbps and OC3072, 160 Gbps).Peer ReviewedPostprint (published version

Aptamerek - az antitestek lehetséges alternatívái

Az anitesteken alapuló eljárások számos különböző szerkezeté élelmiszerszennyező szelektív kimutatását teszik lehetővé. Az ellenanyagok szélesköré alkalmazásának alternatíváját jelenthetik az ún. aptamerek, amelyek jól kötődhetnek számos különféle molekulához. A SELEX eljárás elméleti lehetőséget teremt nagy számú aptamer gyors és költséghatékony elåállítására. Az aptamer-célmolekula kölcsönhatás számos analitikai kimutatási módszer alapjául szolgálhat. Mindezek alapján jogosan feltételezhetå, hogy a napjainkban rutinszeréen alkalmazott antitesteken alapuló kimutatási módszerek mellet, illetve helyett a közeli jövåben megjelenhetnek az aptamer alapú élelmiszervizsgálati módszerek is. Methods based on antibodies provide the possibility for the selective identification of many food containants. The so-called aptamers well combined to different molecules could be the alternative. The SELEX procedure provides a theoretical possibility for a rush and cost- efficient production of many aptamers. The interaction between aptamer and molecule can be the basic for many analytical identification methods. In consideration of all that statuments it can be assumed that beside or instead of identification routine methods on the basic of antibodies also food investigation methods on the basic of aptamers will be avaible in the next future

Cluster computer simulation of buffer sharing schemes under bursty traffic load

In this thesis it is first analyzed the effect that different Average Burst Length, buffer size or number of ports have on the performance in terms of packet loss ratio on shared memory network switches using Complete Sharing as baseline for the memory allocation scheme. Three different shared memory allocation schemes - Sharing with a Minimum Allocation (SMA), Sharing with Maximum Queue lengths (SMXQ), and Dynamic Threshold (DT) - are then analyzed under varied traffic conditions in order to determine the best configuration for each tested scenario. Having determined the best configuration for each individual scheme under all the tested scenarios, DT scheme is then compared against SMA scheme, as well as SMXQ scheme in order to determine which of the conventional shared memory allocation schemes presents a lower packet loss ratio on each tested scenario. A new shared memory allocation scheme referred to in this thesis as ‘Shortest Queue First’ (SQF) scheme is evaluated. SQF aims at decreasing packet loss ratio while maintaining fairness of memory utilization. This proposed scheme is subjected to the same traffic conditions as the other schemes mentioned above; a comparison is then drawn against the conventional scheme with the lowest packet loss ratio for each scenario in order to determine the extent to which packet loss ratio decreases for a switch utilizing the SQF scheme

A General Method for Finding the Most Economical Distributed Router Architecture

In this work we present a novel method to determine the optimal parameters of a router architecture when certain router performance constraints are given. The total financial expense, or cost, is the optimality criterion. We introduce a general, essentially distributed, router architecture model, consisting of locally or remotely located forwarding engines or processing units gathered around a switch of variable speed. Given the following constraints: number of inputs, maximum line interface bandwidth, and maximum packet delay in a router, the presented method finds the optimal amount and distribution of processing power among the various available processing units and the optimal parameters for the switching element. The optimization employs an estimated market-based cost function per element and finds the most economical system solution. The results show that the optimal solutions gather around two extreme points of the solution space, distinguishable by the distribution of the processing power mass and corresponding switch speed. We discuss when, depending on the customer input, one or the other solution is appropriate

Development of geodetic instruments

The main topic of this bachelor thesis is the development of geodetic instruments and a description of some instruments that are currently present on the market. The development is, roughly speaking, based on four periods: archaic, optical, electro optical and electronic. Instruments’ specifications of leading manufacturers are listed at the end of the chapters. On the market, the instruments offer more than just measuring points; moreover, they also provide visual support for measurement, the unification of TPS and GPS system and the terrestrial laser scanning, one of most recent techniques for capturing data about objects in space and the space itself. Through the development we can conclude that the complexity of the instruments and the simplicity of their use increased inversely proportional, which caused changes in the operational requirements of surveyors and in the measurement process itself