scholarly journals CERN Tape Archive: a distributed, reliable and scalable scheduling system

2021 ◽  
Vol 251 ◽  
pp. 02037
Author(s):  
Eric Cano ◽  
Vladimír Bahyl ◽  
Cédric Caffy ◽  
Germán Cancio ◽  
Michael Davis ◽  
...  

The CERN Tape Archive (CTA) provides a tape backend to disk systems and, in conjunction with EOS, is managing the data of the LHC experiments at CERN. Magnetic tape storage offers the lowest cost per unit volume today, followed by hard disks and flash. In addition, current tape drives deliver a solid bandwidth (typically 360MB/s per device), but at the cost of high latencies, both for mounting a tape in the drive and for positioning when accessing non-adjacent files. As a consequence, the transfer scheduler should queue transfer requests before the volume warranting a tape mount is reached. In spite of these transfer latencies, user-interactive operations should have a low latency. The scheduling system for CTA was built from the experience gained with CASTOR. Its implementation ensures reliability and predictable performance, while simplifying development and deployment. As CTA is expected to be used for a long time, lock-in to vendors or technologies was minimized. Finally, quality assurance systems were put in place to validate reliability and performance while allowing fast and safe development turnaround.

2016 ◽  
Vol 2016 (DPC) ◽  
pp. 000324-000341 ◽  
Author(s):  
Chet Palesko ◽  
Amy Palesko

2.5D and 3D packaging can provide significant size and performance advantages over other packaging technologies. However, these advantages usually come at a high price. Since 2.5D and 3D packaging costs are significant, today they are only used if no other option can meet the product requirements, and most of these applications are relatively low volume. Products such as high end FPGAs, high performance GPUs, and high bandwidth memory are great applications but none have volume requirements close to mobile phones or tablets. Without the benefit of volume production, the cost of 2.5D and 3D packaging could stay high for a long time. In this paper, we will provide cost model results of a complete 2.5D and 3D manufacturing process. Each manufacturing activity will be included and the key cost drivers will be analyzed regarding future cost reductions. Expensive activities that are well down the learning curve (RDL creation, CMP, etc.) will probably not change much in the future. However, expensive activities that are new to this process (DRIE, temporary bond/debond, etc.) provide good opportunities for cost reduction. A variety of scenarios will be included to understand how design characteristics impact the cost. Understanding how and why the dominant cost components will change over time is critical to accurately predicting the future cost of 2.5D and 3D packaging.


2015 ◽  
Vol 6 (1) ◽  
pp. 50-57
Author(s):  
Rizqa Raaiqa Bintana ◽  
Putri Aisyiyah Rakhma Devi ◽  
Umi Laili Yuhana

The quality of the software can be measured by its return on investment. Factors which may affect the return on investment (ROI) is the tangible factors (such as the cost) dan intangible factors (such as the impact of software to the users or stakeholder). The factor of the software itself are assessed through reviewing, testing, process audit, and performance of software. This paper discusses the consideration of return on investment (ROI) assessment criteria derived from the software and its users. These criteria indicate that the approach may support a rational consideration of all relevant criteria when evaluating software, and shows examples of actual return on investment models. Conducted an analysis of the assessment criteria that affect the return on investment if these criteria have a disproportionate effort that resulted in a return on investment of a software decreased. Index Terms - Assessment criteria, Quality assurance, Return on Investment, Software product


1988 ◽  
Vol 5 (2) ◽  
pp. 311
Author(s):  
Mozaffar Partowmah

The 14th Annual Conferknce of the Association of Muslim Scientistsand Engineers (ASME) was held during the weekend of qufur 2628,1409/0ctober 7-9, 1988, at the Islamic Center of North America in Plainfield,Indiana. Papers presented at the Conference dealt with a variety of subjectsranging from agriculture and health sciences to car manufacturing tips,computers, industrial, civil and electronic engineering, as well as resourcemanagement and organizational behavior.Members of the AMSS (Association of Muslim Social Scientists) whoattended the AMSE Conference, participated in the sessions with undividedattention. Dr. AbdulHamid AbuSulayman, the AMSS President, in his banquetspeech, stressed the need for an active AMSE that will eventually attracta more sizable number of Muslims in North America and coordinate theirscientific efforts for their common benefit.In a session entitled “Technology Transfer,” the Japanese and Koreanapproaches were contrasted with the Muslim world approach. A highlightof the Conference was the announcement of the A1 Khwarazmi Award thatthe AMSE will award annually to a distinguished Muslim scientist or engineer.The first Al Khwarazmi Award went to Dr. M.A.K. Lodhi of Texas A&MUniversity in appreciation of his continuous support for Muslim studentsand his long-time involvement in the AMSE in addition to his scientific interestand achievements in nuclear physics and field theory.The Best Student Paper Award went to the following: 1) Abdullah M.Elramsisi of Rochester Hill, Michigan for his paper “On Model-based ImageRestoration and Performance Evaluation;” and 2) Khatib Rajab of Morgantown,West Virginia for his paper on “Agricultural Research Needs and Prioritiesin Zanzibar as perceived by Administrators and Extension Workers.”Copies of all of the presented papers were distributed at the Conferenceand will be ppblished in the conference proceedings. Preprints and reprintsmay be obtained by writing to the AMSE office at P.O. Box 38, Plainfield,Indianna, 46168 ...


Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 272
Author(s):  
Ayman M. Atta ◽  
Mohamed H. El-Newehy ◽  
Meera Moydeen Abdulhameed ◽  
Mohamed H. Wahby ◽  
Ahmed I. Hashem

The enhancement of both thermal and mechanical properties of epoxy materials using nanomaterials becomes a target in coating of the steel to protect it from aggressive environmental conditions for a long time, with reducing the cost. In this respect, the adhesion properties of the epoxy with the steel surfaces, and its proper superhyrophobicity to repel the seawater humidity, can be optimized via addition of green nanoparticles (NPs). In-situ modification of silver (Ag) and calcium carbonate (CaCO3) NPs with oleic acid (OA) was carried out during the formation of Ag−OA and CaCO3−OA, respectively. The epoxide oleic acid (EOA) was also used as capping for Ca−O3 NPs by in-situ method and epoxidation of Ag−OA NPs, too. The morphology, thermal stability, and the diameters of NPs, as well as their dispersion in organic solvent, were investigated. The effects of the prepared NPs on the exothermic curing of the epoxy resins in the presence of polyamines, flexibility or rigidity of epoxy coatings, wettability, and coatings durability in aggressive seawater environment were studied. The obtained results confirmed that the proper superhyrophobicity, coating adhesion, and thermal stability of the epoxy were improved after exposure to salt spray fog for 2000 h at 36 °C.


Electronics ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1117
Author(s):  
Bin Li ◽  
Zhikang Jiang ◽  
Jie Chen

Computing the sparse fast Fourier transform (sFFT) has emerged as a critical topic for a long time because of its high efficiency and wide practicability. More than twenty different sFFT algorithms compute discrete Fourier transform (DFT) by their unique methods so far. In order to use them properly, the urgent topic of great concern is how to analyze and evaluate the performance of these algorithms in theory and practice. This paper mainly discusses the technology and performance of sFFT algorithms using the aliasing filter. In the first part, the paper introduces the three frameworks: the one-shot framework based on the compressed sensing (CS) solver, the peeling framework based on the bipartite graph and the iterative framework based on the binary tree search. Then, we obtain the conclusion of the performance of six corresponding algorithms: the sFFT-DT1.0, sFFT-DT2.0, sFFT-DT3.0, FFAST, R-FFAST, and DSFFT algorithms in theory. In the second part, we make two categories of experiments for computing the signals of different SNRs, different lengths, and different sparsities by a standard testing platform and record the run time, the percentage of the signal sampled, and the L0, L1, and L2 errors both in the exactly sparse case and the general sparse case. The results of these performance analyses are our guide to optimize these algorithms and use them selectively.


2021 ◽  
Vol 182 (2) ◽  
pp. 151-162
Author(s):  
I. G. Loskutov

Among the chronicles relating the heroism of the besieged Leningrad, there are pages dedicated to the deeds performed by the staff the world-famous All-Union Research Institute of Plant Industry (VIR, now the N.I. Vavilov All-Russian Institute of Plant Genetic Resources). With the beginning of the war, even before the city was surrounded by the Nazi troops, the government decided to evacuate a number of factories and institutes from Leningrad, including VIR, but the plan failed. Only in winter did the Institute start partial evacuation, although preparations had been going on for a long time. The largest and most important part of the collection was left behind in the besieged city. The remaining employees were forced to work under the hardest conditions of the siege, in unheated premises. In the harsh reality of the winter in 1941–1942, the daily bread rationing was cut down, and hunger raged in the city, killing tens of thousands of city residents, including VIR employees who kept the stored seeds and tubers untouched. The most difficult part was preserving the potato collection. In the spring of 1942, preparations were made for sowing to restore the viability of seeds and tubers in the fields of Leningrad’s suburban area under the fire from the enemy artillery. Only the heroic efforts of VIR’s staff helped to save the collection from destruction and loss of germination. This heroism cost more than 20 experts and scientists their lives. So, the most dangerous period for the Institute was overcome at such price. Immediately after the siege was lifted, a group of experts was sent to Leningrad from Krasnoufimsk to help with selecting seed accessions for urgent reproduction. Working under extreme physical exhaustion in frozen premises, without water or electricity, under continuous shelling, they saved, many at the cost of their own lives, the collection of cultivated plants and their wild relatives, the herbarium, and the scientific library for future generations. 


Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 3084 ◽  
Author(s):  
Kyoungsoo Bok ◽  
Daeyun Kim ◽  
Jaesoo Yoo

As a large amount of stream data are generated through sensors over the Internet of Things environment, studies on complex event processing have been conducted to detect information required by users or specific applications in real time. A complex event is made by combining primitive events through a number of operators. However, the existing complex event-processing methods take a long time because they do not consider similarity and redundancy of operators. In this paper, we propose a new complex event-processing method considering similar and redundant operations for stream data from sensors in real time. In the proposed method, a similar operation in common events is converted into a virtual operator, and redundant operations on the same events are converted into a single operator. The event query tree for complex event detection is reconstructed using the converted operators. Through this method, the cost of comparison and inspection of similar and redundant operations is reduced, thereby decreasing the overall processing cost. To prove the superior performance of the proposed method, its performance is evaluated in comparison with existing methods.


Author(s):  
Arash Farahani ◽  
Peter Childs

Strip seals are used in gas turbine engines between two static elements or between components which do not move relative to each other, such as Nozzle Guide Vanes (NGVs). The key role of a strip seal between NGV segments is sealing between the flow through the main stream annulus and the internal air system, a further purpose is to limit the inter-segmental movements. In general the shape of the strip seal is a rectangular strip that fits into two slots in adjacent components. The minimum clearance required for static strip seals must be found by accounting for thermal expansion, misalignment, and application, to allow correct fitment of the strip seals. Any increase in leakage raises the cost due to an increase in the cooling air use, which is linked to specific fuel consumption, and it can also alter gas flow paths and performance. The narrow path within the seal assembly, especially the height has the most significant affect on leakage. The height range of the narrow path studied in this paper is 0.01–0.06 mm. The behaviour of the flow passing through the narrow path has been studied using CFD modelling and measurements in a bespoke rig. The CFD and experimental results show that normalized leakage flow increases with pressure ratio before reaching a maximum. The main aim of this paper is to provide new experimental data to verify the CFD modelling for static strip seals. The typical flow characteristics validated by CFD modelling and experiments can be used to predict the flow behaviour for future static strip seal designs.


2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Aref M. al-Swaidani ◽  
Waed T. Khwies

Numerous volcanic scoria (VS) cones are found in many places worldwide. Many of them have not yet been investigated, although few of which have been used as a supplementary cementitious material (SCM) for a long time. The use of natural pozzolans as cement replacement could be considered as a common practice in the construction industry due to the related economic, ecologic, and performance benefits. In the current paper, the effect of VS on the properties of concrete was investigated. Twenty-one concrete mixes with three w/b ratios (0.5, 0.6, and 0.7) and seven replacement levels of VS (0%, 10%, 15%, 20%, 25%, 30%, and 35%) were produced. The investigated concrete properties were the compressive strength, the water permeability, and the concrete porosity. Artificial neural networks (ANNs) were used for prediction of the investigated properties. Feed-forward backpropagation neural networks have been used. The ANN models have been established by incorporation of the laboratory experimental data and by properly choosing the network architecture and training processes. This study shows that the use of ANN models provided a more accurate tool to capture the effects of five parameters (cement content, volcanic scoria content, water content, superplasticizer content, and curing time) on the investigated properties. This prediction makes it possible to design VS-based concretes for a desired strength, water impermeability, and porosity at any given age and replacement level. Some correlations between the investigated properties were derived from the analysed data. Furthermore, the sensitivity analysis showed that all studied parameters have a strong effect on the investigated properties. The modification of the microstructure of VS-based cement paste has been observed, as well.


Sign in / Sign up

Export Citation Format

Share Document