Large RAM Research Articles

Static Stiffness Optimization of Large Ram Based on Equivalent Elastic Modulus

The finite element model of heavy-duty machine tool’s ram components has a large number of elements, many contact pairs for assembly and a large-scale optimization calculation, which make the optimization difficult to conduct. To solve this problem, a static stiffness optimization method of the large component based on the equivalent elastic modulus is put forward. The proposed method is applied to super-heavy-duty CNC floor-type milling and boring machine of TK6932 as a case study. Based on the principle of the equivalent stiffness, the ram assembly with complex constraints and contacts is equivalent to a ram part without other components, the calculation method of the equivalent elastic modulus is analyzed and the equivalent elastic modulus formula of the ram under the bending load is derived. Taking the four box-walls’ thickness and the three stiffened-plates’ thickness of the ram as the optimization variables, the minimal volume under static loading as the target and the maximal displacement and stress as the constraints, the optimized mathematical model of the ram’s equivalent static stiffness is established. The results of the optimization are rounded according to the sensitivity analysis. Besides, the optimization effect is proved by simulation through the finite element technology. The optimization procedure and results show that the simplified method based on equivalent elastic modulus presented in the paper can control the calculation scale effectively, and ensure the process of the optimization smooth.

MOBILE SNIFFER AND JAMMER

This system detects the use of GSM mobiles in mobil e restricted areas such as examination halls, hospi tals and other do not disturb areas. The sniffer keeps monitoring the RF level in the area and gives a warning indication if the RF level increases due to mobile activities. This warning indication is send as a me ssage through a GSM module and displayed on a LCD. The pic 16F877A Microcontroller contains internal flash memory of 8 kb along with a large RAM area and internal EEPROM. To make it fit for monitoring and real time system applications microc ontroller is induced with an 8 channel 10 bit A/D c onverter. Liquid crystals are materials that have a molecular structure and will flow like a liquid. It is also a low power device. Some properties of this molecular structure are associated with solids. An antenna wh ose receiving or radiating elements, such a arms of a dipole, are made in the form of an extensible system of metal tubes or rods of a pproximately equal length. Such a design facilities changing the length of antenna elements during tuning and permits the size of ante nna to be reduced when it is not in operation for e xample during transport or storage. Telescopic antennas are used principally i n conjunction with radio receivers, radio transmitt er-receivers, portable television receivers and television receivers installed in mov ing objects. To make it cost effective and to have a small dimension SIM Com is induced with in a powerful single chip processor in tegrating AMR 926EJ-S core and quad band-GSM/GPRS module of SMT type. SIM Com contains a reliable wireless module-SIM900 and is ultra compact.

On-Demand Block-Level Address Mapping in Large-Scale NAND Flash Storage Systems

The density of flash memory chips has doubled every two years in the past decade and the trend is expected to continue. The increasing capacity of NAND flash memory leads to large RAM footprint on address mapping management. This paper proposes a novel Demand-based block-level Address mapping scheme with a two-level Caching mechanism (DAC) for large-scale NAND flash storage systems. The objective is to reduce RAM footprint without excessively compromising system response time. In our technique, the block-level address mapping table is stored in fixed pages (called the translation pages) in the flash memory. Considering temporal locality that workloads exhibit, we maintain one cache in RAM to store the on-demand address mapping entries. Meanwhile, by exploring both spatial locality and access frequency of workloads with another two caches, the second-level cache is designed to cache selected translation pages. In such a way, both the most-frequently-accessed and sequentially accessed address mapping entries can be stored in the cache so the cache hit ratio can be increased and the system response time can be improved. To the best of our knowledge, this is the first work to reduce the RAM cost by employing the demand-based approach on block-level address mapping schemes. The experiments have been conducted on a real embedded platform. The experimental results show that our technique can effectively reduce the RAM footprint while maintaining similar average system response time compared with previous work.

Decrease in horn size and increase in age of trophy sheep in Alberta over 37 years

ABSTRACTLong‐term data (1974–2011) from harvested bighorn rams (Ovis canadensis) in Alberta, Canada, suggested a reduction in horn size and in the proportion of trophy rams in the provincial population over time. Age at harvest increased over time, suggesting slower horn growth. Rams that experienced favorable environmental conditions early in life had rapid horn growth and were harvested at a younger age than rams with slower horn growth. Guided nonresident hunters did not harvest larger rams than residents, suggesting that few large rams were available. Resident hunter success declined in recent years. Despite an apparently stable population, successive cohorts produced a decreasing harvest of trophy rams. We suggest that unrestricted harvest based on a threshold horn size led to a decline in the availability of trophy rams. That decline is partly an inevitable consequence of selective hunting that removes larger rams. Although our analysis does not establish that evolution of smaller horns caused the observed decline in both horn size and harvest of trophy rams, we suggest that intensive trophy hunting may have artificially selected for a decrease in horn growth rate. © 2013 The Wildlife Society.

On a [formula omitted]-fold joint [formula omitted]-spotty Lee weight enumerator

Nowadays, high speed memory systems having large capacity use high-density RAM chips with wide I/O data. These chips are prone to multiple random bit errors (known asm-spotty byte errors) when encountered with high energy particles. To detect or correct such errors, a new class of error-control codes called byte error-control codes have been introduced and studied. In this paper, we define and study a g-fold joint m-spotty Lee weight enumerator of byte error-control codes over the ring of integers modulo ℓ (ℓ≥2 an integer) and over arbitrary finite fields. We also derive some MacWilliams type identities for this enumerator.

The LAMBDA photon-counting pixel detector

The Medipix3 photon-counting detector chip has a number of novel features that are attractive for synchrotron experiments, such as a high frame rate with zero dead time and high spatial resolution. DESY are developing a large-area Medipix3-based detector array (LAMBDA). A single LAMBDA module consists of 2 by 6 Medipix3 chips on a ceramic carrier board, bonded to either a single large silicon sensor or two smaller high-Z sensors. The readout system fits behind the carrier board to allow module tiling, and uses a large on-board RAM and multiple 10 Gigabit Ethernet links to permit high-speed readout. Currently, the first large silicon modules have been constructed and read out at low speed, and the firmware for highspeed readout is being developed. In addition to these silicon sensors, we are developing a germanium hybrid pixel detector in collaboration with Canberra for higher-energy beamlines. Canberra have produced a set of 256-by-256-pixel planar germanium sensors with 55μm pitch, and these are currently being bonded to Medipix3 readout chips by Fraunhofer IZM (Berlin).

LAMBDA — Large Area Medipix3-Based Detector Array

Medipix3 is a photon-counting readout chip for X-ray detection. It has a small pixel size (55 μm) and a high frame rate with zero dead time, which makes it attractive for experiments at synchrotrons. Using Medipix3, DESY are developing the LAMBDA (Large Area Medipix3-Based Detector Array) system. A single LAMBDA module carries either a single large silicon sensor of 1536 by 512 pixels, or two smaller high-Z sensors. The sensor is bonded to 12 Medipix3 chips, and mounted on a ceramic carrier board. The readout system for the module then provides a fast FPGA, a large RAM and four 10 Gigabit Ethernet links to allow operation at high frame rates. Multiple modules may then be tiled together a larger area. Currently, the first large silicon modules have been constructed and tested at low speed, and the firmware for fast readout is being developed.

Design of a ``Digital Atlas Vme Electronics'' (DAVE) module

ATLAS-SCT has developed a new ATLAS trigger card, 'Digital Atlas Vme Electronics' (``DAVE''). The unit is designed to provide a versatile array of interface and logic resources, including a large FPGA. It interfaces to both VME bus and USB hosts.DAVE aims to provide exact ATLAS CTP (ATLAS Central Trigger Processor) functionality, with random trigger, simple and complex deadtime, ECR (Event Counter Reset), BCR (Bunch Counter Reset) etc. being generated to give exactly the same conditions in standalone running as experienced in combined runs.DAVE provides additional hardware and a large amount of free firmware resource to allow users to add or change functionality.The combination of the large number of individually programmable inputs and outputs in various formats, with very large external RAM and other components all connected to the FPGA, also makes DAVE a powerful and versatile FPGA utility card.

Dynamic soil parameters and Case damping for high-capacity long H-piles

Uncertainty exists in signal-matching techniques. The quake and damping obtained may not be the actual response of the soil. In this paper, the final sets, strain gauge readings, pile driving analyzer, and Case pile wave analysis program of 12 high-capacity long H-piles at the end of initial driving as well as two of them at restrike are studied. Measured and deduced data show that the soil response underneath the pile toes has limited movement and yielding despite the piles being set using very heavy hammer rams and large ram drops. The quake and damping decrease with increased shearing strain and shearing stress, but are influenced by pile whipping, rebounded stress wave, and load-transfer mechanism. The lumped Case damping factor decreases with increased side resistance to total resistance ratio. This factor can decrease or increase with time due to changes in the load-transfer mechanism after set-up, thus affecting the proportion of viscous damping of soil along the pile shaft and at the pile toe. A Case damping model is proposed that approximates the lumped Case damping factor as the sum of hysteretic damping of the pile and viscous damping of the surrounding soil. The effects of variation in load distribution and set-up along the pile shaft in layered soils and incomplete mobilization of soil at the pile toe on the Case damping factors are explained.

Competitive 10Be measurements below 1 MeV with the upgraded ETH–TANDY AMS facility

Competitive 10Be measurements at energies as low as 0.75 MeV are now possible with the compact ETH AMS system TANDY. In this paper we describe and discuss the modifications that led to the significantly improved performance for 10Be at the 0.6 MV accelerator. Results from the first routine measurement show that 10Be on the upgraded TANDY is now fully competitive with larger AMS systems with respect to background and measurement precision. The total efficiency for 10Be is comparable to our large 6 MV Tandem system and thus sufficient for the full range of applications in the Earth and Environmental Sciences.

Energetic analysis of hard facing and weld cladding of an air powered drop hammer damaged ram

This paper studies problems of hard facing of damaged and initially cracked mechanical engineering heavy parts of complex geometry such as large rams of air powered drop hammers. During long-term exploitation, these parts are subjected to thermal fatigue due to cyclic temperature changes and variable impact compression. Taking into consideration high ram costs and difficulties to purchase ram, the necessity of its reparation becomes obvious. The choices of the most suitable technologies of hard facing and welding of an initially cracked ram are also studied here. Besides the techno-economic analysis, an energetic analysis is performed as an additional criterion in assessment of the proposed technology.

Fluorides or hydrides? 41Ca performance at VERA’s 3-MV AMS facility

Recent improvements in isobaric suppression for medium-mass isotopes, e.g. 41Ca, offer new possibilities for tandem accelerators with terminal voltages of 3 MV or lower; i.e. when dealing with particle energies ⩽1 MeV/amu. In particular, detection of 41Ca requires sufficient discrimination of the stable isobar 41K. We explored the limits of 41Ca detection at our 3-MV AMS facility by means of different types of particle detectors: The ΔTOF method, which is based on the different flight-time of isobars after passing a thick absorber foil. The second method makes use of a new type of compact ionization chamber: 41K and 41Ca are separated in energy due to their different energy loss in the detector entrance foil and the detector gas, which is measured via a segmented anode. At VERA we measured 41Ca/Ca ratios below 10 −13 for commercial CaF 2 material serving as blank samples. CaH 2 sputter targets, with the extraction of CaH 3 - , yielded background ratios as low as 41Ca/Ca = 1 × 10 −15. The typical measurement precision at VERA for 41Ca measurements was between 2% and 5%. These results demonstrate that AMS facilities based on 3-MV tandems have reached the sensitivity level of larger AMS facilities for a wide range of applications, with the advantage of high overall efficiency and sample throughput.

Packing Techniques for Virtex-5 FPGAs

Packing is a key step in the FPGA tool flow that straddles the boundaries between synthesis, technology mapping and placement. Packing strongly influences circuit speed, density, and power, and in this article, we consider packing in the commercial FPGA context and examine the area and performance trade-offs associated with packing in a state-of-the-art FPGA---the Xilinx ® Virtex TM -5 FPGA. In addition to look-up-table (LUT)-based logic blocks, modern FPGAs also contain large IP blocks. We discuss packing techniques for both types of blocks. Virtex-5 logic blocks contain dual-output 6-input LUTs. Such LUTs can implement any single logic function of up to 6 inputs, or any two logic functions requiring no more than 5 distinct inputs. The second LUT output has reduced speed, and therefore, must be used judiciously. We present techniques for dual-output LUT packing that lead to improved area-efficiency, with minimal performance degradation. We then describe packing techniques for large IP blocks, namely, block RAMs and DSPs. We pack circuits into the large blocks in a way that leverages the unique block RAM and DSP layout/architecture in Virtex-5, achieving significantly improved design performance.

실시간 운영체제에서 작업량 관찰에 기반한 저전력 기법의 설계 및 구현

오늘날의 내장형 이동 시스템은 MP3플레이어나 디지털 캠코더와 같이 하나의 기능만을 지원했던 단일 응용프로그램 시스템에서 PMP(Portable Multimedia Player), PDA(Personal Digital Assistants)와 같이 MPEG, W3플레이어, 전자사전, DMB(Digital Multimedia Broadcasting), 게임, 통신 기능 등을 모두 포함하는 하나의 디지털 컨버전스 기기로 변화해가고 있다. 이러한 변화는 CPU 성능 향상과 메모리, 저장장치의 증가, LCD의 크기 증가와 같은 하드웨어적인 요구사항의 증가로 이어졌고, 이로 인해 단말기에서 소모하는 전력이 그에 비례하여 증가하였다. 소모 전력의 증가에 따른 배터리 용량의 증가는 더딘 상황이며, 이를 해결하기 위해 소프트웨어적으로 소모 전력을 감축시키는 연구들이 많이 진행되고 있다. 본 논문에서는 소모 전력 감축 기법이 적용된 실시간 운영체제 UbiFOSTM을 ARM9계열의 MBA2440에 탑재하였다. 전력 감축 기법으로 시스템 작업량 관찰에 기반한 동적 전력 관리 기법과 장치 전력 관리기법을 적용하였다. 본 논문의 저전력 기법을 통해 작업량에 따라 24% 이상의 소모 전력 감축효과가 있음을 확인하였다. In recent years, embedded mobile systems have been expanding their application domains from embedded portable devices which only execute a specialized application such as MP3 player or digital camcoder to digital convergence devices which execute more complicated applications converged various functionalities such as video and audio play, digital dictionary, DMB, games, phone, etc. As it requires the increasing hardware performance such as more faster CPU and more larger RAM, display, disk size, it has brought about a corresponding increase in power consumption. However, coupled with relatively small gains in battery capacity over recent years, the importance of software architecture including intelligent power management has become paramount. In this paper, we have ported UbiFOSTM with energy saving techniques on the ARM9-based MBA2440 platform. For energy savings, we adapted the dynamic power management and the device power management schemes based on monitoring workload. Experimental results with some well-known applications show that proposed low power technique could save energy up to 24 %.

The compact 14C AMS facility of Paleo Labo Co., Ltd., Japan

A compact AMS system was installed by a private company in Japan for a 14C dating business. Since this system was designed to be very compact with a low voltage accelerator, it has unique features compared to larger AMS systems. For example, the stripper gas pressure has to be maintained at a high level to dissociate molecular ions. However, it cannot be too high because ion transmission decreases at higher stripper gas pressures due to increased angular straggling of the ions scattered by the high density stripper gas.The optimum pressure of the stripper gas for the lowest background and the highest transmission was investigated.With all the features of the compact system, the produced measurements can be of quite high precision.In the ten months after the installation of the equipment in November 2004, we have measured more than 1400 dating samples.

Phase Segregation Susceptibility of ZA27 Alloy at Different Shear Rates

Back extrusion technique was employed to characterize phase segregation tendency of mechanically stirred ZA27 alloy at different deformation rates. Variation of segregation intensity with ram diameter was found to follow opposite trends at low and high ram speeds. At sufficiently high ram speeds, small rams are of better performance in minimizing segregation whereas at low ram speeds, large rams result in less pronounced segregation. In addition, increasing ram speed invariably decreases segregation degree. Back extrusion at very high shear rates provided via a Drop Extruder Apparatus capable of displacing ram at speeds in excess of 1m/s results in production of very homogeneous products in terms of solid fraction as well as size distribution of globules.

Some Mediterranean plant species (Lavandula spp. and Thymus satureioides) act as potential ‘plant nurses’ for the early growth of Cupressus atlantica

The mycorrhizal status of several representative shrub species (Lavandula spp. and Thymus satureioides) in Moroccan semiarid ecosystems, was evaluated as well as their contribution to the mycorrhizal potential of the soil. Furthermore, the rhizosphere soils collected under these target species were tested for their influence on the growth of Cupressus atlantica, a tree species whose natural stands has declined in this area. Soil samples were collected from the rhizosphere of L. stoechas, L. dentata and of C. atlantica existing in the experimental area. Control samples were randomly collected from bare soil sites, away from plant influence. All the target species formed AM symbiosis and the extent of AM fungal colonization was not significantly different between plant species. No significant difference was detected between the total number of AM fungal spores of the bare soil and those recorded in the root zones of target species and C. atlantica. Three genera of AM fungi (Scutellospora, Glomus and Acaulospora) were present in the rhizospheres of the plant species and in the bare soil. The number of mycorrhizal propagules in soil originating from around the four target plant species was significantly higher than the one in the bare soil (Figure 1). The most probable number (MPN) of mycorrhizal propagules per 100 g of dry soil ranged from 7.82 (bare soil) to 179.7 (L. dentata and C. atlantica) and 244.5 (L. stoechas and T. satureioides). As the total number of spores was not different for the soil of different origins, the increase of the mycorrhizal soil infectivity (MSI) mainly resulted from larger AM mycelial networks that constituted the main source of AM fungal inoculum. In addition, this MSI enhancement was linked with changes in the functioning of soil microbial communities. In a glasshouse experiment, the growth of C. atlantica seedlings was significantly higher in the C. atlantica and in the shrub species soils than in the bare soil. Although the AM inoculum potential is not sufficient to ensure the development of forest trees in Mediterranean ecosystems, the use of plant nurses such as T. satureioides or Lavandula spp. could be of great interest to restore a self-sustaining vegetation cover to act against desertification.

A universal and competitive compact AMS facility

The 600kV AMS facility at ETH/PSI has been upgraded to a universal platform for AMS at low energies allowing to perform studies of 10Be, 14C, 26Al, 41Ca, 129I, 236U and Pu. The most significant improvement in performance is due to a new gas ionisation chamber of much better energy resolution. Performance for 10Be, 14C, 26Al, 129I and Pu isotopes is now competitive with larger AMS facilities. The background in 41Ca measurements is sufficiently low to measure samples for biomedical applications.

The Athlit ram bronze casting reconsidered: scientific and technical re-examination

Visual examination and advanced analytical techniques were used to re-examine the large Hellenistic bronze naval ram found in 1980 at Athlit Bay, south of Haifa, Israel. The aim was to reevaluate the method used to manufacture this massive bronze casting. In contrast to an earlier study of the ram that suggested that it was manufactured using the sand-casting method, a technique not otherwise known prior to the late Medieval period, the current study suggests that the ram was manufactured by the lost-wax technique commonly used during the Classical and Hellenistic periods. Newly gathered data point to a selective use of the direct and indirect lost-wax casting methods to manufacture different parts of the ram, and allow postulation of the innovative use of the direct lost-wax casting method to fulfil the ram design requirements.

Combined circuit and architectural level variable supply-voltage scaling for low power

Energy-efficient processor design is becoming more and more important with technology scaling and with high performance requirements. Supply-voltage scaling is an efficient way to reduce energy by lowering the operating voltage and the clock frequency of processor simultaneously. We propose a variable supply-voltage (VSV) scaling technique based on the following key observation: upon an L2 miss, the pipeline performs some independent computations but almost always ends up stalling and waiting for data, despite out-of-order issue and other latency-hiding techniques. Therefore, during an L2 miss we scale down the supply voltage of certain sections of the processor in order to reduce power dissipation while it carries on the independent computations at a lower speed. However, operating at a lower speed may degrade performance, if there are sufficient independent computations to overlap with the L2 miss. Similarly, returning to high speed may degrade power savings, if there are multiple outstanding misses and insufficient independent computations to overlap with them. To avoid these problems, we introduce two state machines that track parallelism on-the-fly, and we scale the supply voltage depending on the level of parallelism. We also consider circuit-level complexity concerns which limit VSV to two supply voltages, stability and signal-propagation speed issues which limit how fast VSV may transition between the voltages, and energy overhead factors which disallow supply-voltage scaling of large RAM structures such as caches and register file. Our simulations show that VSV achieves an average of 7.7% total processor power reduction with 0.9% performance degradation in an eight-way, out-of-order-issue processor that implements deterministic clock gating and software prefetching, across all the SPEC2K benchmarks. For those benchmarks that have high L2 miss rates (more than 4 misses per 1000 instructions), VSV achieves 23.0% reduction in total processor power with 2.0% performance degradation on average.