Tag Field Research Articles

A Study of Subject Headings vs. User Generated Tags

User-generated tagging or folksonomy is one of the most popular Web 2.0 applications and has attracted the interest of libraries and information centres, which has developed services that facilitate user community collaboration. In the digital environment, social tagging has the potential to overcome certain limitations of traditional subject headings. The main objectives of this research paper are to identify the scope of user-generated tags as compared to Subject Heading Lists and to explore the extent to which these user-generated tags can be used to enhance subject access. In this research paper, the problem is comparison between the Subject heading List and user generated tags. This work is an exploratory research and has followed a case study method. Five searches were performed in Library Thing using its Tag mash feature (essentially a keyword search of the user tag field) using 5 tags. After searching articles and interpreting all data, a comparison between the subject heading list and User-generated tags have been made.

Accelerating Nested Conditionals on CGRA With Tag-Based Full Predication Method

CGRA (Coarse-grained Reconfigurable Architecture) has been widely considered as one of the most promising computing architectures to exploit spatial parallelism. Compared with the typical general-purpose architectures which are instruction-driven, most of the state-of-art CGRAs are designed following the data-driven strategy, leading to difficulties while dealing with control-flow (nested if-then-else structures, NITE). Tackling with this problem, existing techniques such as partial predication and full predication introduce extra conditional move and select operations, while state-based full predication (SFP) introduces sleep and awake operations to correctly implement the basic function of NITE. Meanwhile, performance degradation is also incurred by these redundant operations. In this paper, a novel tag-based full predication (TFP) strategy is proposed, trying to eliminate redundant operations and thus accelerate NITE on CGRAs. The extra tag field is added to each instruction word to implement distributed nullification and parallel tag register (TReg) overwriting. Hardware support for TFP is present, and experimental validation is based on RTL-level simulation with manual mapping. Results show that our method achieves over 30% performance gain on average compared with SFP at the expense of around 5% additional power consumption and ignorable area overhead.

Gaia DR2 unravels incompleteness of nearby cluster population: new open clusters in the direction of Perseus

Context. Open clusters (OCs) are popular tracers of the structure and evolutionary history of the Galactic disc. The OC population is often considered to be complete within 1.8 kpc of the Sun. The recent Gaia Data Release 2 (DR2) allows the latter claim to be challenged. Aims. We perform a systematic search for new OCs in the direction of Perseus using precise and accurate astrometry from Gaia DR2. Methods. We implemented a coarse-to-fine search method. First, we exploited spatial proximity using a fast density-aware partitioning of the sky via a k-d tree in the spatial domain of Galactic coordinates, (l, b). Secondly, we employed a Gaussian mixture model in the proper motion space to tag fields quickly around OC candidates. Thirdly, we applied an unsupervised membership assignment method, UPMASK, to scrutinise the candidates. We visually inspected colour-magnitude diagrams to validate the detected objects. Finally, we performed a diagnostic to quantify the significance of each identified over-density in proper motion and in parallax space. Results. We report the discovery of 41 new stellar clusters. This represents an increment of at least 20% of the previously known OC population in this volume of the Milky Way. We also report on the clear identification of NGC 886, an object previously considered an asterism. This study challenges the previous claim of a near-complete sample of OCs up to 1.8 kpc. Our results reveal that this claim requires revision, and a complete census of nearby OCs is yet to be found.

FastTag: A Technique to Protect Cache Tags Against Soft Errors

Cache memories are very relevant components in modern processors, and therefore, their protection against soft errors is important to ensure reliability. One important element in caches is the tag fields, which are critical to keep data integrity and achieve a high hit ratio. To protect them against soft errors, a parity bit or a single error correction (SEC) code is commonly used. In that case, on each cache access, the parity bit is checked or the SEC code decoded on each cache way to detect and correct errors. In this paper, FastTag, a novel approach to protect cache tags is presented and evaluated. The proposed scheme computes the parity or SEC bits on the incoming address and compares the result with the tag and parity bits stored in each cache way. This avoids parity recomputation or SEC decoding, thus reducing the circuit complexity. This is corroborated by the evaluation results that show how FastTag requires an area, delay, and power overhead much lower than the conventional techniques that are currently used.

An Improved Watermarking-Based Algorithm of Tamper Detection for Low-Cost EPC C1G2 RFID Tags

Data tampering as one of the primary security issues in RFID-enabled applications has been presented in recent years and proposals based on watermarking have been put forward to address different aspects of tampering in RFID tags. However, most of current researches are focused on the way of generating the watermark from the data to be protected and embedding it into the tag field (usually the field of serial number or SN) used as the cover medium, thus the innate structural coding relationship as a new clue to guess out the hidden watermark might be ignored. In this paper, this flaw has been fully considered, and a novel tamper detection method using CFB based encryption to hide the location clues is presented. Although it cant resist the attack from statistical analysis either, theoretical analysis has demonstrated that our scheme outperforms its previous counterparts in data security.

Syntax and Behavior Semantics Analysis of Network Protocol of Malware

PDF HTML阅读 XML下载 导出引用 引用提醒 恶意软件网络协议的语法和行为语义分析方法 DOI: 10.3724/SP.J.1001.2011.03858 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金(60703076, 61073179); 国家高技术研究发展计划(863)(2009AA01Z435, 2007AA01Z451) Syntax and Behavior Semantics Analysis of Network Protocol of Malware Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:网络协议逆向分析是恶意软件分析的一项重要内容.现有的网络协议逆向分析方法主要考虑获取消息和协议语法,缺少数据的行为语义,导致分析者难以在网络数据和恶意软件行为之间建立起对应关系.提出一种协议的语法规范和字段行为语义分析方法,该方法利用基于虚拟执行环境的动态程序分析技术,通过分析恶意对网络数据的解析过程提取协议语法信息,并根据恶意软件对协议字段的使用方式获取字段的程序行为语义.结合API 拦截和指令执行监控,该方法降低了分析复杂度,提高了分析效率.在所设计和实现的原型系统Prama(protocol reverse analyzer for malware analysis)上的实验结果表明,该方法能够较为准确地识别字段,提取协法规范,并能在命令字段与其引起的程序行为之间建立起有效的对应关系. Abstract:Network protocol reverse analysis is an important aspect of malware analysis. There are many different network protocols and every protocol contains different types of fields that result in various malware behaviors. Without the protocol syntax and filed semantics, analyzers cannot understand how malware interacts with the outside network. This paper presents a syntax and a behavior semantics analysis method of the network protocol. By monitoring the way malware parse the network data and by using different fields in a virtual execution environment, this method can identify protocol fields, extract protocol syntax and correlate each syntax with malware behaviors, accordingly. This paper designs and implements the prototype Prama (protocol reverse analyzer for malware analysis). Experimental results show that this method can correctly infer protocol syntax and tag fields with meaningful malware behaviors. 参考文献 相似文献 引证文献

An on-chip instruction cache design with one-bit tag for low-power embedded systems

On-chip instruction cache is a potential power hungry component in embedded systems due to its large chip area and high access-frequency. Aiming at reducing power consumption of the on-chip cache, we propose a Reduced One-Bit Tag Instruction Cache ( ROBTIC), where the cache size is judiciously reduced and the cache tag field only contains the least significant bit of the full-tag. We develop a cache operational control scheme for ROBTIC so that with the one-bit cache tag, the program locality can still be efficiently exploited. For applications where most of the memory accesses are localized, our cache can achieve similar performance as a traditional full-tag cache; however, the power consumption of the cache can be significantly reduced due to the much smaller cache size, narrower tag array (just one bit), and tinier tag comparison circuit being used. Experiments on a set of benchmarks implemented in CMOS 180 nm process technology demonstrate that our proposed design can reduce up to 27.3% dynamic power consumption and 30.9% area of the traditional cache when the cache size is fixed at 32 instructions, which outperforms the existing partial-tag based cache design. With the cache size customization, a further 47.8% power saving can be achieved. Our experimental results also show that when implemented in the deep sub-micron technologies where the leakage power is not ignorable, our design is still efficient – a coherent power saving trend (about 22%) has been observed for technologies from 130 nm down to 65 nm.

Low-Overhead Architecture for Security Tag

A security-tagged architecture is one that applies tags on data to detect attack or information leakage, tracking data flow. The previous studies using security-tagged architecture mostly focused on how to utilize tags, not how the tags are implemented. A naive implementation of tags simply adds a tag field to every byte of the cache and the memory. Such a technique, however, results in a huge hardware overhead. This paper proposes a low-overhead tagged architecture. We achieve our goal by exploiting some properties of tag, the non-uniformity and the locality of reference. Our design includes the use of uniquely designed multi-level table and various cache-like structures, all contributing to exploit these properties. Under simulation, our method was able to limit the memory overhead to 0.685%, where a naive implementation suffered 12.5% overhead.

A reduced crustal magnetization zone near the first observed active hydrothermal vent field on the Southwest Indian Ridge

Inversion of near‐bottom magnetic data reveals a well‐defined low crustal magnetization zone (LMZ) near a local topographic high (37°47′S, 49°39′E) on the ultraslow‐spreading Southwest Indian Ridge (SWIR). The magnetic data were collected by the autonomous underwater vehicle ABE on board R/V DaYangYiHao in February‐March 2007. The first active hydrothermal vent field observed on the SWIR is located in Area A within and adjacent to the LMZ at the local topographic high, implying that this LMZ may be the result of hydrothermal alteration of magnetic minerals. The maximum reduction in crustal magnetization is 3 A/M. The spatial extent of the LMZ is estimated to be at least 6.7 × 104 m2, which is larger than that of the LMZs at the TAG vent field on the Mid‐Atlantic Ridge (MAR), as well as the Relict Field, Bastille, Dante‐Grotto, and New Field vent‐sites on the Juan de Fuca Ridge (JdF). The calculated magnetic moment, i.e., the product of the spatial extent and amplitude of crustal magnetization reduction is at least −3 × 107 Am2 for the LMZ on the SWIR, while that for the TAG field on the MAR is −8 × 107 Am2 and that for the four individual vent fields on the JdF range from −5 × 107 to −3 × 107 Am2. Together these results indicate that crustal demagnetization is a common feature of basalt‐hosted hydrothermal vent fields at mid‐ocean ridges of all spreading rates. Furthermore, the crustal demagnetization of the Area A on the ultraslow‐spreading SWIR is comparable in strength to that of the TAG area on the slow‐spreading MAR.

Isolation and physiological characterization of two novel, piezophilic, thermophilic chemolithoautotrophs from a deep‐sea hydrothermal vent chimney

Two novel, thermophilic piezophiles, capable of chemolithoautotrophic growth, are successfully cultivated and isolated from a black smoker chimney at the TAG field (Mid Atlantic Ridge: MAR) by using a piezophilic cultivation technique. Both strains (strains 106 and 108) represent dominant cultivated populations of the microbial communities in the chimney surface habitat. Strain 106 represents typically thin, long spiral cells under the piezophilic growth condition but short bent cells under the non-piezophilic condition. It is a strictly chemolithoautotrophic gammaproteobacterium using reduced sulfur compounds as the electron donors, and nitrate and O(2) as the electron acceptors. Based on the 16S rRNA gene sequence, strain 106 would represent a novel genus of the previously uncultivated group (Symbiont Group I; a potentially novel family) within the Gammaproteobacteria, and 'Thioprofundum lithotrophica' gen. nov., sp. nov. is proposed. Strain 108 is a short, oval rod at any of the growth pressures. It is a facultative chemoautotroph, capable of both chemolithoautotrophic growth with H(2) and S oxidations and organotrophic growth with complex organics or organic acids using nitrate and O(2) as the electron acceptors. The chemolithoautotrophic growth is strictly piezophilic and under the organotrophic growth condition, it grows at conventional pressures (0.1 MPa). Strain 108 is phylogenetically distinctive from any of the previously described genera of the family Rhodobacteraceae within the Alphaproteobacteria, and 'Piezobacter thermophilus' gen. nov., sp. nov. is proposed. The piezophilic cultivation technique can be a powerful tool to isolate and characterize the previously uncultivated phylotypes in the deep-sea hydrothermal vent environments.

Geochemical characteristics of hydrothermal plumes above the TAG and Broken Spur fields of the Mid-Atlantic Ridge

The paper reports data on the distribution of solute (Mn, Zn, Cu, Pb, and Cd) and particulate (Fe, Mn, Zn, Cu, Pb, Ni, and Co) species of metals in hydrothermal plumes above the active TAG and Broken Spur hydrothermal fields (26° N and 29° N in the MAR rift valley, respectively). Sediment-trap data on fluxes of hydrothermal-sedimentary material in the areas indicate that (i) the predominant Zn source for the metalliferous sediments at the TAG field is material precipitating from a plume of neutral buoyancy, and (ii) the predominant source of Fe and Co is redeposited ore material coming from the area of extensive settling of sulfides.

Evolving patterns of the fluids within the TAG hydrothermal field

The mixing of seawater/hydrothermal fluid within the large seafloor hydrothermal sulfide deposits plays a key role in the formation processes of the sulfide deposits. Some issues attract considerable attentions in the study of seafloor hydrothermal system in recent years, such as the relationships among different types of vent fluids, the characteristics of chemical compositions and mineral assemblages of the hydrothermal deposits and their governing factors. Combined with the measured data of hydrothermal fluid in the TAG field, the thermodynamic model of mixing processes of the heated seawater at different temperatures and the hydrothermal fluid is calculated to understand the precipitation mechanism of anhydrite and the genetic relationships between the black and white smoker fluids within the TAG mound. The results indicate that the heating of seawater and the mixing of hydrothermal fluid/seawater are largely responsible for anhydrite precipitation and the temperature of the heated seawater is not higher than 150°C and the temperature of the end-member hydrothermal fluid is not lower than 400°C. Based on the simulated results, the evolving patterns of fluids within the TAG deposit are discussed. The mixed fluid of the end-member hydrothermal fluid and the seawater heated by wall rock undergoes conductive cooling during upflowing within the deposit and forms “White Smoker” eventually. In addition, the end-member hydrothermal fluid without mixed with seawater, but undergoing conductive cooling, vents out of the deposit and forms “Black Smoker”.

A ring network with VLAN tag

AbstractThe proposed Ring Network with VLAN Tag offers the features of wrapping/steering control functions and 1+1 path protection function, maintaining compatibility with the Ethernet media access control scheme. The key technology for “Path concept” is VLAN tag swapping operation. A set of primary and backup paths is defined between ring nodes, which are distinguished by a flag bit in VLAN tag field. On failure detection, the path is switched within the path set by the tag swapping. Tag swapping at the failure detection node, while tag swapping at the source node achieves steering operation, achieves Wrapping operation. The restoration behavior is almost the same as that of Resilient Packet Ring (RPR). Since the tag swapping control is based on hardware processing, high‐speed operation is also expected. Furthermore, because the paths are independently designed from the physical topology, the scheme can be applied to networks other than physical ring networks. The proposed scheme will fit to the path control for next‐generation Ethernet over WDM system. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 166(1): 60–66, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20422

On the rise of turbulent plumes: Quantitative effects of variable entrainment for submarine hydrothermal vents, terrestrial and extra terrestrial explosive volcanism

The maximum height reached by a turbulent plume rising in a stratified environment is a key tool to estimate the flux released at its source, particularly for large‐scale flows because flux can often be very hard to measure directly. This height is known to be mainly controlled by the stratification of the ambient fluid, source buoyancy flux, and the efficiency of turbulent mixing between the plume and the external fluid. The latter effect has been only superficially explored in spite of its fundamental control on the dynamics. Here we show that commonly used one‐dimensional models incorporating a constant entrainment coefficient do not provide satisfying predictions. We propose a new model allowing for variable entrainment which gives excellent predictions of maximum heights reached by laboratory plumes in stratified environments. We then apply our formalism to natural plumes produced by explosive volcanic eruptions under terrestrial, paleo‐Martian, and Venusian conditions and by submarine hydrothermal activity at mid‐ocean ridges. Source mass discharge rates deduced from maximum volcanic column heights for terrestrial eruptions are found to be greater than those estimated with the commonly used constant entrainment parameterization by a factor of 2. In the paleo‐Martian atmosphere, existing models overestimate plume heights by 14–27%. In the current atmosphere of Venus, the maximum height reached by a volcanic plume is also found to be smaller than previously estimated for large eruption rates. The source heat flux released by the TAG field (Atlantic Ocean) deduced from several submarine hydrothermal plumes is found greater by a factor 3 with our model.

Low-temperature hydrothermal deposits in the rift zone of the Mid-Atlantic Ridge

New data on the low-temperature hydrothermal deposits of the Snake Pit, TAG, Broken Spur, and Lucky Strike fields in the rift valley of the Mid-Atlantic Ridge (MAR) obtained during the 47th cruise of the R/V Akademik Mstislav Keldysh are reported. These deposits are related to focused and diffuse flows of hydro- thermal solutions and the material precipitated from hydrothermal plumes. Electron microscopy study allowed us to identify protoferrihydrite, ferrihydrite, goethite, hematite, Mn-feroxyhyte, and Fe-vernadite. Fe-free ver- nadite, akaganeite, opal, nontronite, lepidocrocite, and jarosite occur in subordinate amounts. Bacteria-like forms made up of protoferrihydrite particles replaced with ferrihydrite, nontronite, and goethite along with par- ticles of Fe-free vernadite and opal were found. The contents of major, minor, and noble metals were deter- mined in samples with AAS, INAA, and the direct chromatographic method. Elevated PGE contents were established in the low-temperature hydrothermal deposits of the MAR for the first time. The highest PGE con- tents were detected in the inner zone of Fe-Mn crusts on the surface of a hydrothermal chimney in the Snake Pit field ((ppm) 0.13 Pd, 0.12 Rh, and 0.03 Pt, along with 16.5 Au, 642 Ag, and 355 Se) and in the Au-depleted crust on the surface of a sulfide ore fragment in the Lucky Strike field (0.12 ppm Pd and 0.04 ppm Rh along with 0.03 ppm Au, 683 ppm Se, and 1.5 wt % Ba).

The Outline of RFID Tag Field Trials in the Publishing Industry

The Outline of RFID Tag Field Trials in the Publishing Industry

Comparative analysis of the mineral and chemical compositions of black smoker smoke at the TAG and Broken Spur hydrothermal fields, mid-Atlantic ridge

The paper presents newly obtained data on the fluxes of hydrothermal-sedimentary material collected with sedimentation traps within 3 m from the bottoms of black smokers at the TAG and Broken Spur hydrothermal fields and reports the results of comparative analysis of the mineralogical and chemical compositions of this material. The sedimentary material deposited near the vent was determined to account to approximately 3% of the overall mass of the orebody. The results demonstrate that, in both cases, the trap material is characterized by high contents of ore components and ore-forming chemical elements (Fe, Cu, Zn, and Co), and Se, As, Sb, Ba, and P compared to tholeiitic basalts from which these elements are leached. However, the material of a more “mature” (having an age of 40–50 ka) hydrothermal spring at the TAG field contains 40% Fe hydroxides, in contrast to the material of a spring at the Broken Spur field (age <1000 yr) whose material is dominated by sulfides (72%) and contains much pyrrhotite. These springs also show principal differences between the enrichment coefficients for Se (by a factor of 4.8), As (3), Ca (4.1), and Si (5.2). These differences are thought to reflect various evolutionary stages of the circulating hydrothermal systems.

A SEU-protected cache memory-based on variable associativity of sets

SRAM cache memories suffer from single event upset (SEU) faults induced by energetic particles such as neutron and alpha particles. To protect these caches, designers often use error detection and correction codes, which typically provide single-bit error detection and even correction. However, these codes have low error detection capability or incur significant performance penalties. In this paper, a protected cache scheme based on the variable associativity of sets is presented. In this scheme, cache space is divided into sets of different sizes with variable tag field lengths. The other remained bits of tags are used for protecting the tag using a new protection code. This leads to protect the cache without compromising performance and area with respect to the similar one, fully associative cache. The scheme provides high SEU detection coverage as well as high performance. Moreover, reliability and mean-time-to-failure (MTTF) equations are derived and estimated. The results obtained from fault injection experiments and several trace files from SPEC2000 reveal that the proposed scheme exhibits a good performance near to fully associative cache but can detect high percent of SEU faults.

HIERARCHICAL SET-ASSOCIATE CACHE FOR HIGH-PERFORMANCE AND LOW-ENERGY ARCHITECTURE

This paper presents a new cache scheme based on varying the size of sets in the set-associative cache hierarchically. In this scheme, all sets at a hierarchical level have same size but are k times more than the size of sets in the next level of hierarchy where k is called division factor. Therefore the size of tag fields associated to each set is variable and it depends on the hierarchy level of the set it is in. This scheme is proposed to achieve higher hit ratios with respect to the two conventional schemes namely set-associative and direct mapping. The proposed scheme has been simulated with several standard trace files SPEC 2000 and statistics are gathered and analyzed for different cache configurations. The results reveal that the proposed scheme exhibits a higher hit ratio compared to the two well-known mapping schemes, namely set-associative and direct mapping. Moreover, the area and power consumption of this scheme is less than full-associative scheme.

Hierarchical Binary Set Partitioning in Cache Memories

In this paper, a new cache placement scheme is proposed to achieve higher hit ratios with respect to the two conventional schemes namely set-associative and direct mapping. Similar to set-associative, in this scheme, cache space is divided into sets of different sizes. Hence, the length of tag fields associated to each set is also variable and depends on the partition it is in. The proposed mapping function has been simulated with some standard trace files and statistics are gathered and analyzed for different cache configurations. The results reveal that the proposed scheme exhibits a higher hit ratio compared to the two well-known mapping schemes, namely set-associative and direct mapping, using LRU replacement policy.