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High-Performance Accurate and Approximate Multipliers for FPGA-Based Hardware AcceleratorsUllah, Salim, Rehman, Semeen, Shafique, Muhammad, Kumar, Akash 07 February 2023 (has links)
Multiplication is one of the widely used arithmetic operations in a variety of applications, such as image/video processing and machine learning. FPGA vendors provide high-performance multipliers in the form of DSP blocks. These multipliers are not only limited in number and have fixed locations on FPGAs but can also create additional routing delays and may prove inefficient for smaller bit-width multiplications. Therefore, FPGA vendors additionally provide optimized soft IP cores for multiplication. However, in this work, we advocate that these soft multiplier IP cores for FPGAs still need better designs to provide high-performance and resource efficiency. Toward this, we present generic area-optimized, low-latency accurate, and approximate softcore multiplier architectures, which exploit the underlying architectural features of FPGAs, i.e., lookup table (LUT) structures and fast-carry chains to reduce the overall critical path delay (CPD) and resource utilization of multipliers. Compared to Xilinx multiplier LogiCORE IP, our proposed unsigned and signed accurate architecture provides up to 25% and 53% reduction in LUT utilization, respectively, for different sizes of multipliers. Moreover, with our unsigned approximate multiplier architectures, a reduction of up to 51% in the CPD can be achieved with an insignificant loss in output accuracy when compared with the LogiCORE IP. For illustration, we have deployed the proposed multiplier architecture in accelerators used in image and video applications, and evaluated them for area and performance gains. Our library of accurate and approximate multipliers is opensource and available online at https://cfaed.tu-dresden.de/pd-downloads to fuel further research and development in this area, facilitate reproducible research, and thereby enabling a new research direction for the FPGA community.
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Assessment of the sustainability of the rice-maize cropping system in the Red River Delta of Vietnam and developing reduced tillage practices in rice-maize system in the area: Review paperLe, Thi Thanh Ly 19 August 2015 (has links)
Rice and maize are global staple food and play an important role in world’s food security strategy. Vietnam is one of rice leading export countries but annually it has to import a considerate amount of maize for cattle food processing. Red River Delta in the north of Vietnam is the second rice bucket of the country, which is responsible formore than 20% of total rice production. The priority crops in the areas are rice and maize and rice-maize system is the leading cropping system in the area. Currently, it is reported that the rice-maize cropping system is not sustainable and its profit is reducing in most of production areas in the Red River Delta. Improving rice cropping system aims is not only to increase rice and maize yields and production but also to improve the land use efficiency, decline the cost of the production and to increase system sustainability. To increase sustainability there must be a linkage of various factors. This review emphasizes on increasing rice-maize crop sustainability by applying appropriate agriculture practices such as reducing chemical fertilization and intensive tillage. / Gạo và ngô là nguồn lương thực chính cho toàn cầu và đóng một vai trò quan trọng trong chiến lược an ninh lương thực của thế giới. Việt Nam là một trong những nước dẫn đầu về xuất khẩu gạo nhưng hàng năm vẫn phải nhập một số lượng lớn ngô để chế biến thức ăn gia súc. Đồng bằng sông Hồng là một trong hai vựa lúa lớn của Việt Nam sản xuất khoảng 20% sản lượng lúa gạo của cả nước. Ở đồng bằng sông Hồng, lúa và ngô là hai cây trồng chính là hệ canh tác lúa-ngô là cơ cấu cây trồng hàng đầu trong vùng. Tuy nhiên, trong những năm gần đây, rất nhiều đánh giá cho thấy hệ thống canh tác lúa-ngô là hệ thống canh tác không bền vững và các lợi nhuận của mang lại từ cơ cấu canh tác ở hầu hết các khu vực sản xuất ở vùng đồng bằng sông Hồng của Việt Nam đã và đang giảm dần. Do đó, việc cải thiện cơ cấu canh tác lúa-ngô không chỉ nhằm mục đích tăng năng suất lúa và ngô mà còn nâng cao hiệu quả sử dụng đất, giảm chi phí sản xuất và tăng cường hệ thống canh tác bền vững. Tuy nhiên, để tăng tính bền vững của hệ thống canh tác thì phải liên kết nhiều yếu tố khác nhau. Bài viết này dựa vào các kết quả nghiên cứu của các tác giả khác nhau để đưa ra những giải pháp tích cực làm tăng tính bền vững của hệ thống canh tác lúa-ngô bằng cách áp dụng các phương pháp canh tác hợp lý như giảm sử dụng phân hóa học và các biện pháp canh tác thâm canh như áp dụng phương pháp làm đất tối thiểu.
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Sammankoppling av tryckluftssystem i SBC / Connection of compressed air system at SBCKüller, Victor, Garp, Viktor January 2022 (has links)
Detta examensarbete har genomförts på AstraZenecas produktionsanläggning i Gärtuna, Södertälje och behandlar ett av AstraZenecas dyraste media, tryckluft. Mer specifikt behandlar rapporten tryckluftsanläggningen i byggnad 921 (B921) där optimal drift på kompressorerna inte har lyckats uppnås på grund av att kapaciteten på kompressorerna inte matchar flödesbehovet i byggnaden, som i sin tur har skapat onödiga kostnader och utgifter. Det centrala tryckluftssystemet som finns i Gärtuna har på vissa delar en underkapacitet och är hårt belastat. Detta beror på att Astra Zeneca också har underkapacitet på elnätet i Gärtuna som minskar möjligheterna till att sätta in större kompressorer på området. Genom att sammankoppla dessa system kan det centrala systemet avlastas samtidigt som kompressorerna i B921 får arbeta som de är tillverkad för att göra. Målet med arbetet har varit att hitta lösningar för att uppnå en bättre drift på kompressorerna i B921 samtidigt som redundansen i byggnaden och hela produktionsområdet i stort ökar genom att bygga ihop tryckluftssystemet i B921 med det centrala tryckluftssystem som finns på Gärtuna och betjänar övriga delar av anläggningen. Samtidigt som det centrala värmeåtervinningssystemet ansluts till B921 för att optimera energiförbrukningen genom att ta tillvara på den värme som uppstår vid komprimering av luft. Efter genomfört arbete framkom att bästa lösningsalternativet för att åtgärda den ojämna och osäkra driften på kompressorerna är att koppla samman tryckluftssystemet i B921 med det centrala tryckluftssystemet som betjänar övriga delar av Gärtuna. Genom att göra detta kommer kompressorerna kunna arbeta kontinuerligt på ett effektivt flöde. Samtidigt kommer B921 att kunna förse det centrala systemet med luft, något som ökar tillgängligheten för hela Gärtuna. Dock kommer ingen luft att kunna erhållas från det centrala systemet då B921 arbetar på ett högre tryck. Vidare så kommer värmeåtervinningen att öka när det centrala värmeåtervinningssystemet ansluts till kompressorernas kylning. Något som även kommer minska utsläppen av koldioxid då behovet av fjärrvärme kommer minska. / This thesis work has been done together with AstraZeneca at their manufacturing site in Gärtuna, Södertälje. The work treats the compressed air system which is their most expensive media. This report will be about the compressed air system in building 921 (B921) where the operation is not optimal due to low flow requirements which do not meet the specifications of the compressor. This has created unnecessary costs and losses in energy.The central compressed air system at Gärtuna that supplies most of the production has under capacity. While there is under capacity in the electricity network at Gärtuna which limits the possibility to use bigger compressors. By connecting these systems the central system will be relieved and the compressors in B921 will get the workload they are designed for. The goal with this thesis have been to achieve a better operation for the compressors in B921 as well as achieve higher redundancy in both B921 and gärtuna by connecting the compressed air systems. At the sametime the heat recovery system will be connected to B921 to optimize the recovery by recovering the heat in the compressor. After completing the work, it emerged that the best alternative to fix the workload on the compressors is to connect the compressed air system in B921 with Gärtuna. By doing this the compressors workload will be the same as they are designed for. This will increase the availability for Gärtuna. B921 will not be able to receive air from the centralsystem, due to a higher pressure in B921. The heat recovery will be increased when the heat recovery system will be connected to the compressors. Which will decrease the emissions of carbondioxide due to less need of district heating.
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Two-phase flow instabilities in an open natural circulation systemManthey, René 20 December 2022 (has links)
Die vorliegende Arbeit befasst sich mit der Stabilitätsuntersuchung von offenen Naturumlaufsystemen als Grundlage zur Verwendung als passives Wärmeabfuhrsystem im Sicherheitsbehälter eines Siedewasserreaktors.
Der Betrieb eines solchen Systems im Naturumlauf basiert einzig auf der Ausbildung eines Dichtegradienten, der infolge einer freien Konvektion zu einer Strömung innerhalb dieses Systems führt.
Dieser Dichtegradient im Arbeitsfluid wird durch die Wärmezu- und -abfuhr hervorgerufen.
Der sich ausbildende und kontinuierlich steigende Massenstrom geht bei Erreichen der Sättigungstemperatur in Massenstromoszillationen, den sogenannten Zweiphasenströmungsinstabilitäten, über.
Mit steigender Temperatur des Arbeitsfluides kehrt der Massenstrom zu einer stabilen Strömung und kontinuierlichen Wärmeabfuhr zurück, jedoch als Zweiphasenströmung.
Es wurde an der Technischen Universität Dresden eine Versuchsanlage errichtet, die den Gebäudekondensator des KERENA\textsuperscript{TM}(ehemals SWR1000)-Reaktorkonzepts nachstellt, um die Anlagen- und die Betriebscharakteristik hinsichtlich geometrischer Einflüsse zu bewerten.
Mit Hilfe hochauflösender Temperatur und Volumendampfgehaltsmessung wurde festgestellt, dass bei parallel angeordneten Steigrohren die durch Kondensationsschläge hervorgerufenen Druckschläge stark reduziert oder sogar unterbunden werden konnten.
So fungiert eines der Steigrohre als Puffer für rückströmendes unterkühltes Fluid aus der Wärmesenke in dem anderen.
Zusammengefasst wurde zudem die Betriebscharakteristik in Stabilitätskarten, die die stabile Einphasenströmung, die instabile Zweiphasenströmung und die stabile Zweiphasenströmung eindeutig voneinander abgrenzt.
Die Vorhersage der Stabilitätsgrenze zwischen instabiler und stabiler Zweiphasenströmung durch einen analytischen Ansatz ist gelungen.
Das zugrundeliegende Modell für ein solches offenes Naturumlaufsystem wurde durch die Methode der gewichteten Residuen und die Finite-Volumen-Methode gelöst und mit Hilfe der Proper Orthogonal Decomposition auf ein Modell niedriger Ordnung reduziert (ROM).
Vergleichsrechnungen mit einem entwickelten Abbild des Versuchsstandes GENEVA unter Verwendung des bereits validierten Systemcodes ATHLET der \textit{Gesellschaft für Anlagen- und Reaktorsicherheit (GRS) gGmbH} bestätigten die berechneten Betriebszustände und letztendlich die durch die lineare Stabilitätsuntersuchung ermittelte Stabilitätsgrenze.
Eben dieses ROM bildet die Zweiphasenströmung mittels des \textit{Drift-flux mixture} Modells ab, welches die relativen Geschwindigkeiten jeder Phase berücksichtigt.
Die nichtlineare Stabilitätsuntersuchung dieses ROMs ergab an ausgewählten Referenzbetriebspunkten superkritische Hopfbifurkationen, die nur durch die Detektion aufkommender stabiler Grenzzyklen während der numerischen Integration nachgewiesen werden konnten.
Parameterstudien zur Stabilitätsanalyse können durch dieses ROMs unter erheblicher Reduktion von Rechenaufwand durchgeführt werden.
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A database accelerator for energy-efficient query processing and optimizationLehner, Wolfgang, Haas, Sebastian, Arnold, Oliver, Scholze, Stefan, Höppner, Sebastian, Ellguth, Georg, Dixius, Andreas, Ungethüm, Annett, Mier, Eric, Nöthen, Benedikt, Matúš, Emil, Schiefer, Stefan, Cederstroem, Love, Pilz, Fabian, Mayr, Christian, Schüffny, Renè, Fettweis, Gerhard P. 12 January 2023 (has links)
Data processing on a continuously growing amount of information and the increasing power restrictions have become an ubiquitous challenge in our world today. Besides parallel computing, a promising approach to improve the energy efficiency of current systems is to integrate specialized hardware. This paper presents a Tensilica RISC processor extended with an instruction set to accelerate basic database operators frequently used in modern database systems. The core was taped out in a 28 nm SLP CMOS technology and allows energy-efficient query processing as well as query optimization by applying selectivity estimation techniques. Our chip measurements show an 1000x energy improvement on selected database operators compared to state-of-the-art systems.
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Influence of Curved Geometries on the Fatigue Life of Laser Peened ComponentsVasu, Anoop 30 May 2014 (has links)
No description available.
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Reduced Order Modeling Methods for Turbomachinery DesignBrown, Jeffrey M. January 2008 (has links)
No description available.
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VALIDATING STEADY TURBULENT FLOW SIMULATIONS USING STOCHASTIC MODELSChabot, John Alva 07 October 2015 (has links)
No description available.
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Model Order Reduction of Incompressible Turbulent FlowsDeshmukh, Rohit January 2016 (has links)
No description available.
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Reduced order modeling, nonlinear analysis and control methods for flow control problemsKasnakoglu, Cosku 10 December 2007 (has links)
No description available.
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