数字灰尘撞击传统网络--集成于一立方毫米组件上可随意使用的传感器和通信系统

由于小型化、集成度和电源处理等方面技术的提高,完全不使用金属导线的传感器/通信系统可以集成于体积只有一个沙粒大小的组件或网络中。它的应用远到军用传感器网络,近到工业质量控制。 被称之为“聪明灰尘计划”的研究目标是探索独立传感器节点的小型化和能耗的最低界限。该设备可被用来监控气象图谱或在运货前设置一个谷物食品盒,使得仓库管理员可以测定该产品在运输途中是否暴露于风雨之中而有潮气。这些细小聪明的节点或尘埃存在的可能,是因为近期集成了的微电机系统、无线电通信和数字电路。由(美)国防高级研究计划局(阿灵顿、弗吉尼亚)资助的该研究项目正由加州伯克利大学的研究员们进行着。     

Neural Networks for Full-Scale Protein Sequence Classification: Sequence Encoding with Singular Value Decomposition

A neural network classification method has been developed as an alternative approach to the search/organization problem of protein sequence databases. The neural networks used are three-layered, feed-forward, back-propagation networks. The protein sequences are encoded into neural input vectors by a hashing method that counts occurrences ofn-gram words. A new SVD (singular value decomposition) method, which compresses the long and sparsen-gram input vectors and captures semantics ofn-gram words, has improved the generalization capability of the network. A full-scale protein classification system has been implemented on a Cray supercomputer to classify unknown sequences into 3311 PIR (Protein Identification Resource) superfamilies/families at a speed of less than 0.05 CPU second per sequence. The sensitivity is close to 90% overall, and approaches 100% for large superfamilies. The system could be used to reduce the database search time and is being used to help organize the PIR protein sequence database.     

Using latent semantic indexing for multilanguage information retrieval

In this paper, a method for indexing cross-language databases for conceptual query matching is presented. Two languages (Greek and English) are combined by appending a small portion of documents from one language to the identical documents in the other language. The proposed merging strategy duplicates less than 7% of the entire database (made up of different translations of the Gospels). Previous strategies duplicated up to 34% of the initial database in order to perform the merger. The proposed method retrieves a larger number of relevant documents for both languages with higher cosine rankings when Latent Semantic Indexing (LSI) is employed. Using the proposed merge strategies, LSI is shown to be effective in retrieving documents from either language (Greek or English) without requiring any translation of a user's query. An effective Bible search product needs to allow the use of natural language for searching (queries). LSI enables the user to form queries with using natural expressions in the user's own native language. The merging strategy proposed in this study enables LSI to retrieve relevant documents effectively using a minimum of the database in a foreign language.Michael W. Berry is an Assistant Professor in the Department of Computer Science at the University of Tennessee, Knoxville. He recieved a Ph.D. in Computer Science from the University of Illinois at Urbana-Champaign in 1990, and an M.S. in Applied Mathematics from North Carolina State University at Raleigh in 1983. His current interests include scientific computing, parallel algorithms, information retrieval applications, and computer performance evaluation. He is a member of the ACM, SIAM, and the IEEE Computer Society.Paul G. Young is now employed as an Associate Consultant with Oracle Government Services in Knoxville, TN. In 1984 he graduated from the Gordon-Conwell Theological Seminary in S. Hamilton, MA and became an Ordained Presbyterian Minister (PCUSA). He later received an M.S. in Computer Science from the University of Tennessee in 1994.     

The influence of speed, grade and mass during simulated off road bicycling

The purpose of this investigation was to examine the effects of bicycle mass, speed, and grade on oxygen consumption (VO2), heart rate (HR), and ratings of perceived exertion (RPE) during a simulated off-road riding paradigm. Nine adult subjects with mean +/- SD age, mass, and VO2 max of 26.1 +/- 5.6 years, 71.7 +/- 7.5 kg, 56.6 +/- 5.2 ml x kg(-1) x min(-1) respectively, were trained to ride a fully suspended Trek Y-22 mountain bike on a treadmill with a 3.8 cm bump affixed to the belt. Riders completed a maximum of nine separate trials encompassing three different bike masses (11.6, 12.6 and 13.6 kg), 3 speeds (2.7, 3.6 and 4.5 m x s(-1)), and 3 grades (0, 2.5, and 5%). Throughout a trial, bike mass and speed remained constant while riding grade was increased every 5 min. During simulated off-road riding on a fully suspended mountain bike, increases in speed and grade significantly increased VO2, heart rate, and RPE. Increases in bike mass had no significant effects on VO2, heart rate or RPE. In addition, speed and grade changes interacted to differentially affect VO2, heart rate, and RPE at all speeds and grades.     

Maximum Cardinality Search for Computing Minimal Triangulations of Graphs

We present a new algorithm, called MCS-M, for computing minimal triangulations of graphs. Lex-BFS, a seminal algorithm for recognizing chordal graphs, was the genesis for two other classical algorithms: LEX M and MCS. LEX M extends the fundamental concept used in Lex-BFS, resulting in an algorithm that not only recognizes chordality, but also computes a minimal triangulation of an arbitrary graph. MCS simplifies the fundamental concept used in Lex-BFS, resulting in a simpler algorithm for recognizing chordal graphs. The new algorithm MCS-M combines the extension of LEX M with the simplification of MCS, achieving all the results of LEX M in the same time complexity.     

Effect of angle of incidence during deposition on Ti-Pd-Au conductor film adhesion

The influence of a number of the preparation conditions on the adhesive properties of the Ti-Pd-Au metallization on Ta₂N film resistors was investigated. Test samples consisted of a filament-evaporated conductor film on an unpatterned Ta₂N film on glass, sapphire and Al₂O₃ ceramic substrates. The adhesive properties of the Ti-Pd-Au films were examined as a function of the angle of incidence at which the Ti and Pd atoms were deposited. In addition the adhesive properties were examined after heat treatment in air and after electroplating gold. Transmission electron microscopy and density measurements established that at higher angles of incidence (>60°) Ti and Pd films became increasingly porous and that adhesion at the Ti-Pd interface degraded rapidly upon exposure to air. Both evaporated and plated Au layers appear to offer little protection for films evaporated under these conditions. Good adhesion was found to be independent of the substrate material and of the method used for gold deposition when the Ti-Pd films were evaporated at angles of incidence of 48° or less.     

Comparison of natural convection flows under VHTR type conditions modeled by both the conservation and incompressible forms of the Navier-Stokes equations

This paper illustrates a comparative study to analyze the physical differences between numerical simulations obtained with both the conservation and incompressible forms of the Navier-Stokes equations for natural convection flows in simple geometries. The purpose of this study is to quantify how the incompressible flow assumption (which is based upon constant density advection, divergence-free flow, and the Boussinesq gravitational body force approximation) differs from the conservation form (which only assumes that the fluid is a continuum) when solving flows driven by gravity acting upon density variations resulting from local temperature gradients. Driving this study is the common use of the incompressible flow assumption in fluid flow simulations for nuclear power applications in natural convection flows subjected to a high heat flux (large temperature differences). A series of simulations were conducted on two-dimensional, differentially heated rectangular geometries and modeled with both hydrodynamic formulations. From these simulations, the selected characterization parameters of maximum Nusselt number, average Nusselt number, and normalized pressure reduction were calculated. Comparisons of these parameters were made with available benchmark solutions for air with the ideal gas assumption at both low and high heat fluxes. Additionally, we generated specific force quantities and velocity and temperature distributions to provide a basis for further analysis. The simulations and analysis were then extended to include helium at the Very High Temperature gas-cooled Reactor (VHTR) normal operating conditions. Our results show that the consequences of incorporating the incompressible flow assumption in high heat flux situations may lead to unrepresentative results. The results question the use of the incompressible flow assumption for simulating fluid flow in an operating nuclear reactor, where large temperature variations are present.     

Cleaning for Improved Indoor Air Quality: an Initial Assessment of Effectiveness

Abstract A study was conducted to characterize the indoor environment of a multifloor, multiuse, nonproblem, noncompliant building through long-term monitoring for biological, chemical, and particulate pollutants. The study also assessed the effects of cleaning on indoor air quality by providing a program to monitor baseline levels, providing a rigorous (deep) cleaning of the building, and then continuing to monitor after implementation of a standardized, improved, cleaning program. To assess the effectiveness of the cleaning program, air, surface, and dust data from monitoring prior to the cleaning program were compared with those obtained while the improved housekeeping program was in place. Correlations between pollutants and other environmental factors were studied. The data suggest that the improved cleaning program contributed to indoor air quality through the reduction of airborne dust mass, total volatile organic compounds, and culturable bacteria and fungi.     

Indx and findphrases,a system for generating indexes for ditroff documents

Creating back-of-the-book indexes is a difficult task involving intelligent and clerical processes. Programs have generally not achieved the level of intelligence required to perform the intelligent process of selecting terms for the index. Semi-automatic indexing programs perform the clerical process of preparing entries once the terms have been selected. The programs do not provide assistance in term determination and most require flooding the text with indexing commands. indx differs from other semi-automatic indexing programs mainly because it does not require the insertion of indexing commands into the text to be indexed. The method by which indx assists in the creation of an index is introduced and compared with the characteristics of the other programs. This method includes the use of a program that aids the term determination process. The design, implementation, and application of indx are presented. Areas in which indx may be improved or enhanced are identified. An index of this paper created with indx is included as an example.