bluuebunny/crossref_metadata_2025 huggingface dataset:
CONTRACTING OUT WAR?: PRIVATE MILITARY COMPANIES, LAW AND REGULATION IN THE UNITED KINGDOM
Authors: Clive Walker , Dave Whyte
Published: August 2005

It was Robert Nozick who, distinguishing the classical liberal ‘night-watchman State’ which protected citizens against violence and enforced contracts on their behalf, conjured instead the ‘ultra-minimal State’1in which the task of the State is confined to the monopolization of violence rather than the actual provision of security (unless paid for by citizens by choice). On the face of it, it seems that Western governments are increasingly keen to move towards this model of the ultra-minimal State and to allow even the provision of force to be assumed by private enterprise on a contractual model in which the rich or the desperate may choose to avail themselves of fortifications at the going rate while the rest take their chances in life. The ultra-minimal State is left with a residual steering2policy role in which the parameters of contractual engagement for protection can be set. In short, it appears that nothing is sacrosanct in the onward march of the principles of neo-liberalism. Even the ultimate bastions of establishment—Her Majesty's armed forces—are not immune from processes of commodification and marketization that have previously been applied to core functions such as policing3and imprisonment.4
THE PRECARIOUS POSITION OF EMBASSY AND CONSULAR EMPLOYEES IN THE UNITED KINGDOM
Authors: Garnett Richard
Published: August 2005

Governments, in their diplomatic and consular establishments abroad, typically employ a wide range of people apart from career diplomats and civil servants. Translators, secretaries, drivers, clerks, technical support staff, librarians and chefs are among the jobs that are commonly performed in embassies and consulates. Significantly, many of these subordinate positions are filled by nationals and residents of the forum State, that is, the country in which the embassy or consulate is located. (By contrast, diplomatic or senior policy positions in the organization will almost always be held by nationals of the sending State.) The sending State, particularly if it is a developing country, will often have little choice but to employ local residents to perform many routine tasks given the exorbitant cost of importing a labour force from abroad. From the perspective of the employee of a mission, the nature of the work to be performed may be little different from that carried out for its own government or even the private sector.
II. Conventional Weapons: A Cluster Of Developments
Authors: Mcclelland Mbe J
Published: August 2005

The adoption of Protocol V to the UN Convention on Certain Conventional Weapons represents a shift in focus for weapons law towards the long-term after-effects of weapons. This note considers this development.
II. Legality Of Use Of Force (Serbia And Montenegro v Belgium) (Serbia And Montenegro v Canada) (Serbia And Montenegro v France) (Serbia And Montenegro v Germany) (Serbia And Montenegro v Italy) (Serbia And Montenegro v Netherlands) (Serbia And Montenegro v Portugal) (Serbia And Montenegro v United Kingdom): Preliminary Objections. Judgment Of 15 December 20041
Authors: Gray Christine
Published: August 2005

This is a surprising-and disquieting-judgment which raises serious questions about the role of the Court. The Legality of Use of Force cases began in 1999 when the Federal Republic ofYugoslavia (FRY)2 first brought an action against ten NATOStates for their use of force in Kosovo.3 In December 2004 the Court decided unanimously that it had no jurisdiction to decide the cases. However, this unanimity masked a fundamental disagreement between the judges: it is apparent from the Joint Declaration of Judges Ranjeva, Guillaume, Higgins, Kooijmans, Al-Khasawneh, Buergenthal and Elaraby that the judges were strongly divided, by eight to seven, on the reasoning which led them to agree that there was no jurisdiction.
Pension Funds and Emerging Markets
Authors: Chan‐Lau Jorge A.
Published: August 2005

This paper focuses on the investment behavior of pension funds in developed and emerging market countries. First, it analyzes the main determinants of the emerging market asset allocation of pension funds in developed countries. Second, it assesses how pension funds in emerging markets have contributed to the development of local securities markets. Third, it analyzes the determinants of pension funds’ investment performance. The paper concludes with a discussion of why the emerging market asset allocation of pension funds in developed countries is likely to increase and what the challenges faced by pension funds in emerging markets are.
Circuit Breakers with Uncertainty about the Presence of Informed Agents: I Know What You Know … I Think
Authors: Ackert Lucy F. , Church Bryan K. , Jayaraman Narayanan
Published: August 2005

This study conducts experimental asset markets to examine the effects of circuit breaker rules on market behavior when agents are uncertain about the presence of private information. Our results unequivocally indicate that circuit breakers fail to temper unwarranted price movements in periods without private information. Agents appear to mistakenly infer that others possess private information, causing price to move away from fundamental value. Allocative efficiencies in our markets are high across all regimes. Circuit breakers perform no useful function in our experimental asset markets.
Using X‐Ray Topography to Inspect Surfaces of Single‐Crystal Components
Authors: Black David
Published: August 2005

X‐ray diffraction topography, which is sensitive to local strain and/or crystallographic orientation, provides a unique view of the surface of single‐crystal samples and can be used to nondestructively inspect for surface and subsurface damage. The attributes of synchrotron‐based X‐ray topography as applied to inspection will be described and illustrated with examples from recent experiments.
Computer‐Assisted Colorimetric Optical Texture Analysis for Ceramic Injection Molding Components
Authors: Gadow R. , Lischka M. , Fischer R.
Published: August 2005

In forming and shaping processes with thermoplastic feedstocks e.g., as in ceramic injection molding, (CIM) the formation of textures is observed. These frozen flow structures are dependent on the rheological properties of the feedstock, geometric factors of the mold, and CIM parameters such as injection velocity, pressure, temperature, etc. The effects of these textures on the mechanical properties of the components produced have to be analyzed and quantified in order to reach high quality and reliability standards. The analytical methods need to be exact and reliable to control and optimize the manufacturing process. In this work, optical texture analysis coupled with electronic color‐data processing high‐resolution image analysis is described. The method takes advantage of the optical anisotropy of ceramic materials such as alumina, zirconia, etc. Thin sections of sintered alumina components were prepared and analyzed by polarized light microscopy. Since the crystal structure of alumina is anisotropic in shape and light refraction, the orientation of the crystals in the sintered component can be seen as optical interference colors in the thin section and its crystal arrangement. This information about the local orientation is automatically monitored and evaluated by electronic image processing based on the standardized CIELAB palette. Based on this information a prediction of the mechanical properties of components can be made, and optimization of mold design and feedstock composition may be initiated on this database.
U.S. Department of Energy's Solid Oxide Fuel Cells: Technical Advances
Authors: Williams Mark C. , Strakey Joseph P. , Surdoval Wayne A.
Published: August 2005

The U.S. Department of Energy's (DOE) Office of Fossil Energy's (FE) National Energy Technology Laboratory (NETL), in partnership with private industries, is leading the development and demonstration of high‐efficiency solid oxide fuel cells (SOFCs) and fuel cell turbine hybrid power generation systems for distributed generation (DG) markets. The DOE FE DG program has three aspects: the Solid State Energy Conversion Alliance (SECA), Central Power Systems, and the High Temperature Electrochemistry Center (HiTEC). NETL is partnering with Pacific Northwest National Laboratory in developing new directions in research under SECA for the development and commercialization of modular, low‐cost, and fuel‐flexible SOFC systems. The SECA initiative, through advanced materials, processing, and system integration research and development (R&D) will bring the fuel cell cost to $400 per kilowatt (kW) by 2010 for stationary and auxiliary power unit markets. The SECA program is currently structured to include six competing industry teams supported by a crosscutting core technology program. DOE is ultimately concerned with coal‐based central power plants. Advanced aspects of solid oxide technology are part of HiTEC R&D.
Electronic Structures and Device Applications of Transparent Oxide Semiconductors: What Is the Real Merit of Oxide Semiconductors?
Authors: Kamiya Toshio , Hosono Hideo
Published: August 2005

The main objective of this review is to provide an idea how to create new functions in oxides and how to find suitable applications only oxides can realize. Oxides have crystal and electronic structures largely different from those of conventional semiconductors such as Si and GaAs. Therefore, we should design suitable applications according to the inherent properties of oxide semiconductors if we intend to develop practical optoelectronic devices using oxides. In this review, we first briefly describe the characteristic features of oxide semiconductors from the viewpoints of crystal and electronic structures. Then three materials and related device applications are shown as examples. N‐type amorphous oxide semiconductors (AOSs) can have electron transport properties superior even to silicon if they are in amorphous states. We propose that AOSs are favorable materials for active layers in low‐temperature thin film device technology and demonstrate high‐performance thin film transistors fabricated at room temperature on flexible plastic sheets. The second example is transparent p‐type semiconductors. Employing chalcogen orbitals and layered crystal structures, large hole mobilities, degenerate p‐type conduction, and room‐temperature stable excitions are rendered in wide bangap materials. Room‐temperature operation of excitonic blue light‐emitting diodes was thereby demonstrated. The last is 12CaO·7Al2O3 in which the use of subnanometer‐sized cages and anions clathrated in the cages creates many chemical, optical, and electronic functions.
Composite Transducer Arrays for the Treatment of Diabetes
Authors: Lee S. , Smith N.B. , Markley D. , Snyder B. , Uzgur A.E. , Pishko Michael , Newnham R.E.
Published: August 2005

A portable transdermal drug delivery system using a composite transducer array has been designed to promote insulin transmission through the skin using ultrasound. Previous investigators used large, heavy sonicators in this type of research. The aim of this study is to demonstrate ultrasound‐mediated transdermal insulin delivery using small cymbal arrays. The cymbal transducer design was chosen because of its light, compact structure and low resonance frequency in water. To increase the spatial ultrasound field for drug delivery through the skin, 2 × 2 and 3 × 3 cymbal arrays were constructed. The performance of these arrays was tested under similar conditions. An ultrasound‐enhanced noninvasive glucose measurement system is also under development, and a comparison with conventional glucose meters was performed. The goal is to develop a noninvasive sensor–actuator array for the treatment of disease.
Merging Biological Self‐Assembly with Synthetic Chemical Tailoring: The Potential for 3‐D Genetically Engineered Micro/Nano‐Devices (3‐D GEMS)
Authors: Sandhage Kenneth H. , Allan Shawn M. , Dickerson Matthew B. , Gaddis Christopher S. , Shian Samuel , Weatherspoon Michael R. , Cai Ye , Ahmad Gul , Haluska Michael S. , Snyder Robert L. , Unocic Raymond R. , Zalar Frank M. , Zhang Yunshu , Rapp Robert A. , Hildebrand Mark , Palenik Brian P.
Published: August 2005

Appreciable global efforts are underway to develop processes for fabricating three‐dimensional (3‐D) nanostructured assemblies for advanced devices. Widespread commercialization of such devices will require: (i) precise 3‐D fabrication of chemically tailored structures on a fine scale and (ii) mass production of such structures on a large scale. These often‐conflicting demands can be addressed with a revolutionary new paradigm that couples biological self‐assembly with synthetic chemistry: Bioclastic and Shape‐preserving Inorganic Conversion (BaSIC). Nature provides numerous examples of microorganisms that assemble biominerals into intricate 3‐D structures. Among the most spectacular of these microorganisms are diatoms (unicellular algae). Each of the tens of thousands of diatom species assembles silica nanoparticles into a microshell with a distinct 3‐D shape and pattern of fine (nanoscale) features. The repeated doubling associated with biological reproduction enables enormous numbers of such 3‐D microshells to be generated (e.g., only 40 reproduction cycles can yield >1 trillion 3‐D replicas!). Such genetic precision and massive parallelism are highly attractive for device manufacturing. However, the natural chemistries assembled by diatoms (and other microorganisms) are rather limited. With BaSIC processes, biogenic assemblies can be converted into a wide variety of new functional chemistries, while preserving the 3‐D morphologies. Ongoing advances in genetic engineering promise to yield microorganisms tailored to assemble nanoparticle structures with device‐specific shapes. Large‐scale culturing of such genetically tailored microorganisms, coupled with shape‐preserving chemical conversion (via BaSIC processes), would then provide low‐cost 3‐D Genetically Engineered Micro/nano‐devices (3‐D GEMs).
THE INFLUENCE OF DARK MATTER HALO ONTO EVOLUTION OF SUPERMASSIVE BLACK HOLE
Authors: ZELNIKOV M. I. , VASILIEV E. A.
Published: August 2005

The influence of dark matter (DM) on the growth of supermassive black holes (SMBHs) is studied. It is shown that gravitational scattering of DM particles on bulge stars leads to diffusion of DM in phase space {m, mz, I} (m denotes the angular momentum and I is the radial action). Appropriate diffusion coefficients are calculated for different bulge models, and it is argued that the diffusion along m axis is the most important effect. It is shown that this process leads to noticeable flow of DM into the black hole (BH), resulting in its power-law growth: M bh ∝ t9/16. Comparison with observational data shows that, in principle, this effect may explain observed masses of SMBHs. Special attention is paid to the corrections related to the innermost region of BH gravitational influence and the diffusion along I axis. Their influence on the BH growth law is shown to be negligible.
ENERGY–MOMENTUM DISTRIBUTION: A CRUCIAL PROBLEM IN GENERAL RELATIVITY
Authors: SHARIF M. , FATIMA TASNIM
Published: August 2005

This paper is aimed to elaborate the problem of energy–momentum in general relativity. In this connection, we use the prescriptions of Einstein, Landau–Lifshitz, Papapetrou and Möller to compute the energy–momentum densities for two exact solutions of Einstein field equations. The space–times under consideration are the nonnull Einstein–Maxwell solutions and the singularity-free cosmological model. The electromagnetic generalization of the Gödel solution and the Gödel metric become special cases of the nonnull Einstein–Maxwell solutions. It turns out that these prescriptions do not provide consistent results for any of these space–times. These inconsistent results verify the well-known proposal that the idea of localization does not follow the lines of pseudotensorial construction but instead follows from the energy–momentum tensor itself. These differences can also be understood with the help of the Hamiltonian approach.
A NOTE ON SPIN CHAIN/STRING DUALITY
Authors: DIMOV H. , RASHKOV R. C.
Published: August 2005

Recently a significant progress in matching the anomalous dimensions of certain class of operators in N = 4 SYM and rotating strings was made. The correspondence was established mainly by use of Bethe ansatz technique applied to the spin s Heisenberg chain model. In a recent paper,16 the author suggested to solve the Heisenberg model by use of sigma model approach. In this current work we generalize the solutions presented in Ref. 16 and comment on the dual string theory. It turns out that our solution is related to a generalized ansatz for rotating strings which can be reduced to the so-called Neumann–Rosochatius integrable system. We comment on the spin chain sigma model and string solutions and the possibilities for a more precise formulation of the string/gauge theory correspondence.
GENERALIZED GALILEI-INVARIANT CLASSICAL MECHANICS
Authors: WOODCOCK HARRY W. , HAVAS PETER
Published: August 2005

To describe the "slow" motions of n interacting mass points, we give the most general four-dimensional (4D) noninstantaneous, nonparticle symmetric Galilei-invariant variational principle. It involves two-body invariants constructed from particle 4-positions and 4-velocities of the proper orthochronous inhomogeneous Galilei group. The resulting 4D equations of motion and multiple-time conserved quantities involve integrals over the worldlines of the other n-1 interacting particles. For a particular time-asymmetric retarded (advanced) interaction, we show the vanishing of all integrals over worldlines in the ten standard 4D multiple-time conserved quantities, thus yielding a Newtonian-like initial value problem. This interaction gives 3D noninstantaneous, nonparticle symmetric, coupled nonlinear second-order delay-differential equations of motion that involve only algebraic combinations of nonsimultaneous particle positions, velocities, and accelerations. The ten 3D noninstantaneous, nonparticle symmetric conserved quantities involve only algebraic combinations of nonsimultaneous particle positions and velocities. A two-body example with a generalized Newtonian gravity is provided. We suggest that this formalism might be useful as an alternative slow-motion mechanics for astrophysical applications.
STRUCTURAL AND DIELECTRIC PROPERTIES OF (1-x) PZN – x PLZT CERAMICS
Authors: THAKUR O. P. , PRAKASH CHANDRA , BHARDWAJ NIDHI
Published: August 2005

The structural and dielectric properties of a PZN-PLZT solid solution were investigated. The formation of a single phase was studied by the addition of PLZT (8/60/40) in the present system. With the increase of PLZT, the content of the pyrochlore phase decreased significantly and PZN ceramics with 100% perovskite phase could be achieved with x>0.6. Dielectric properties were investigated as a function of temperature and frequency. The ferroelectric hysteresis loop shows typical characteristics of ferroelectrics.
CHIRAL LIPID BILAYERS WITH CYLINDRICAL SYMMETRY
Authors: HU ZHAN-NING , LO V. C.
Published: August 2005

In this paper, we have studied the chiral lipid bilayers with the tilted fluid phase where the orientation of the molecular tilt varies as a function of the cylindrical coordinates. The rigorous solution of the equation related to the orientation of the long molecular axis is obtained, which describes the property of the tubules with a modulation in the tilt. When the angle of the molecular director is independent of the cylindrical coordinates θ, z, the patterns formed by chiral molecules can be degenerated to the right-handed helix, the left-handed helix, the straight lines, and the circles. The curvature and torsion of the corresponding curves are given explicitly, which denotes the winding of the molecules around the cylinder. We find also that the angle between the director of the molecule and the local normal direction of the cylinder increases if the radius of the cylinder reduces when the tilted angle ϕ from the equator of the cylinder is uniform.
CONFORMAL THEORY FOR YANG–LEE SINGULARITY OF 2D 3-STATE POTTS MODEL
Authors: WYDRO TOMASZ , McCABE JOHN F.
Published: August 2005

We identify a conformal field theory (CFT) that describes the Yang–Lee edge singularity of the 2-dimensional (2D) 3-state Potts model. The identification is based on a comparison of finite-size scaling measurements to predictions for conformal minimal models. The comparison shows that the Yang–Lee edge singularities of the 2D 3-state Potts and the 2D Ising models are in the same universality class.
MICROCRYSTALLINE SILICON FILMS PREPARED BY VERY HIGH FREQUENCY PLASMA ENHANCED CHEMICAL VAPOR DEPOSITION AT LOW TEMPERATURE
Authors: WU ZHIMENG , LEI QINGSONG , XI JIANPING , YING ZHAO , GENG XINHUA
Published: August 2005

Intrinsic microcrystalline silicon films have been prepared using very high frequency plasma enhanced chemical vapor deposition (VHF-PECVD) at low temperature. The effect of silane concentration and power density on the deposition rate and crystallinity of silicon films has been investigated. The Raman spectra indicates a phase transition from microcrystalline to amorphous phase at silane concentrations of higher than 6%. A growth rate of microcrystalline films as high as 6.6 A/s is achieved at a silane concentration of 6% and the crystalline volume fraction Xc is 39%. We have also observed that the decrease of power density shifts the phase transition to low silane concentration.
FIRST PRINCIPLES CALCULATION OF THE ELECTRONIC AND STRUCTURAL PROPERTIES OF USn3 USING LDA+U METHOD
Authors: POURGHAZI A. , NOURBAKHSH Z.
Published: August 2005

The actinide compounds exhibit a variety of unusual ground states. These states are dominated by the strong electron-electron correlations that are not included in normal density-functional electronic band-structure calculation with the local density approximation. These correlations are taken into account in the local density approximation +U (LDA+U) method.

We have calculated the Coulomb repulsion term U for uranium in USn 3 compound, and investigated the total and partial DOS for USn 3 using LDA+U method. The LDA+U results for USn 3 have been compared with similar results from a ThSn 3 model calculation through which the number of 5f electrons outside the U muffin-tin sphere in USn 3 has been deduced. We have also calculated the electric field gradient (EFG), which may be regarded as a measure of the asymmetry in charge distribution, at the Sn site in USn 3 in LDA , LDA+SO and LDA+SO+U methods, and have shown that the Coulomb repulsion term does not introduce any considerable effect on the electric field gradient at the Sn site.
USING MECHANICAL ENERGY AS A PROBE FOR THE DETECTION AND IMAGING OF SHALLOW BURIED INCLUSIONS IN DRY GRANULAR BEDS
Authors: SEN SURAJIT , KRISHNA MOHAN T. R. , VISCO DONALD P. , SWAMINATHAN SARAVANAN , SOKOLOW ADAM , AVALOS EDGAR , NAKAGAWA MASAMI
Published: August 2005

Mechanical energy, such as sound waves and impulses, have been used to detect shallow buried objects for more than half a century. Yet, very little is understood about how mechanical energy propagates into one of the simplest kinds of soil, namely, a granular bed. Here we present an overview of the state of the art in our understanding of mechanical energy propagation in granular beds.
ON SOME RELIABILITY APPROACHES TO HUMAN AGING
Authors: FINKELSTEIN M. S.
Published: August 2005

Deceleration in mortality rates for old ages is explained via the concept of population heterogeneity. Two simple probabilistic models of biological aging are considered. The first one assumes that some random resource is acquired by an organism at birth. Death occurs when the accumulated wear exceeds the initial random resource. In the second model death occurs as the consequence of a harmful event. A non-homogeneous Poisson and doubly stochastic Poisson processes of harmful events are considered. These models describe possible causes of population heterogeneity.
RELIABILITY DESIGN AND RVaR
Authors: TAPIERO CHARLES S.
Published: August 2005

This paper provides an alternative valuation approach to reliability design based a concept of Value at Risk (VaR) used in finance to measure risk exposure. An accounting of the direct and indirect costs combined with the costs needed to meet contingent claims in case of default is used to redefine the traditional reliability design problem, resulting is a nonlinear optimization problem which we can solve by the usual methods. Applications are used to demonstrate the approach used.
Motion to support rapid interactive queries on node--link diagrams
Authors: Ware Colin , Bobrow Robert
Published: August 2005

Many different problems can be represented as graphs displayed in the form of node--link diagrams. However, when a graph is large it becomes visually uninterpretable because of the tangle of links. We describe a set of techniques that use motion in an interactive interface to provide effective access to larger graphs. Touching a node with the mouse cursor causes that node and the subgraph of closely connected nodes to oscillate. We argue from perceptual principles that this should be a more effective way of interactively highlighting a subgraph than more conventional static methods. The MEGraph system was developed to gain experience with different forms of motion highlighting. Based on positive feedback, three experiments were carried out to evaluate the effectiveness of motion highlighting for specific tasks. All three showed motion to be more effective than static highlighting, both in increasing the speed of response for a variety of visual queries, and in reducing errors. We argue that motion highlighting can be a valuable technique in applications that require users to understand large graphs.
EvoFIT
Authors: Frowd Charlie D. , Hancock Peter J. B. , Carson Derek
Published: August 2005

EvoFIT, a computerized facial composite system is being developed as an alternative to current systems. EvoFIT faces are initially presented to a witness with random characteristics, but through a process of selection and breeding, a composite is "evolved." Comparing composites constructed with E-FIT, a current system, a naming rate of 10% was found for EvoFIT and 17% for E-FIT. Analysis revealed that target age was limiting factor for EvoFIT and a second study with age-appropriate targets visible during composite construction produced a naming rate similar to E-FIT. Two more-realistic studies were conducted that involved young target faces and two current systems (E-FIT and PROfit). Composites from both of these experiments were poorly named but a significant benefit emerged for EvoFIT.
A multimodal learning interface for grounding spoken language in sensory perceptions
Authors: Yu Chen , Ballard Dana H.
Published: August 2005

We present a multimodal interface that learns words from natural interactions with users. In light of studies of human language development, the learning system is trained in an unsupervised mode in which users perform everyday tasks while providing natural language descriptions of their behaviors. The system collects acoustic signals in concert with user-centric multisensory information from nonspeech modalities, such as user's perspective video, gaze positions, head directions, and hand movements. A multimodal learning algorithm uses this data to first spot words from continuous speech and then associate action verbs and object names with their perceptually grounded meanings. The central ideas are to make use of nonspeech contextual information to facilitate word spotting, and utilize body movements as deictic references to associate temporally cooccurring data from different modalities and build hypothesized lexical items. From those items, an EM-based method is developed to select correct word--meaning pairs. Successful learning is demonstrated in the experiments of three natural tasks: "unscrewing a jar," "stapling a letter," and "pouring water."
Interaction cost and shotgun profiling
Authors: Fields Brian A. , Bodik Rastislav , Hill Mark D. , Newburn Chris J.
Published: August 2005

We observe that the challenges software optimizers and microarchitects face every day boil down to a single problem: bottleneck analysis. A bottleneck is any event or resource that contributes to execution time, such as a critical cache miss or window stall. Tasks such as tuning processors for energy efficiency and finding the right loads to prefetch all require measuring the performance costs of bottlenecks.In the past, simple event counts were enough to find the important bottlenecks. Today, the parallelism of modern processors makes such analysis much more difficult, rendering traditional performance counters less useful. If two microarchitectural events (such as a fetch stall and a cache miss) occur in the same cycle, which event should we blame for the cycle? What cost should we assign to each event? In this paper, we introduce a new model for understanding event costs to facilitate processor design and optimization.First, we observe that all instructions, hardware structures, and events in a machine can interact in only one of two ways (in parallel or serially). We quantify these interactions by defining
interaction cost
, which can be zero (independent, no interaction), positive (parallel), or negative (serial).Second, we illustrate the value of using interaction costs in processor design and optimization. In a processor with a long pipeline, we show how to mitigate the negative performance effect of long latency "critical" loops, such as the level-one cache access and issue-wakeup, by optimizing seemingly unrelated resources that
interact
with them.Finally, we propose
shotgun profiling
, a class of hardware profiling infrastructures that are parallelism-aware, in contrast to traditional event counters. Our recommended design requires only modest extensions to current hardware counters, while enabling the construction of full-featured dependence graphs of the microexecution. With these dependence graphs, many types of analyses can be performed, including identifying critical instructions, finding slack, as well as computing costs and interaction costs.
Profile-based adaptation for cache decay
Authors: Sankaranarayanan Karthik , Skadron Kevin
Published: August 2005

"Cache decay" is a set of leakage-reduction mechanisms that put cache lines that have not been accessed for a specific duration into a low-leakage standby mode. This duration is called the decay interval, and its optimal value varies across applications. This paper describes an adaptation technique that analytically finds the optimal decay interval through profiling, and shows that the most important variables required for finding the optimal decay interval can be estimated with a reasonable degree of accuracy using profiling. This work explicitly trades off the leakage power saved in putting
both
the "live" and "dead" lines into standby mode, against its performance and energy costs. It achieves energy savings close to what can be obtained with an omniscient choice of per-benchmark optimal decay interval.
Understanding concurrent earcons
Authors: McGookin David K. , Brewster Stephen A.
Published: August 2005

Two investigations into the identification of concurrently presented, structured sounds, called earcons were carried out. One of the experiments investigated how varying the number of concurrently presented earcons affected their identification. It was found that varying the number had a significant effect on the proportion of earcons identified. Reducing the number of concurrently presented earcons lead to a general increase in the proportion of presented earcons successfully identified. The second experiment investigated how modifying the earcons and their presentation, using techniques influenced by auditory scene analysis, affected earcon identification. It was found that both modifying the earcons such that each was presented with a unique timbre, and altering their presentation such that there was a 300 ms onset-to-onset time delay between each earcon were found to significantly increase identification. Guidelines were drawn from this work to assist future interface designers when incorporating concurrently presented earcons.
Toward kilo-instruction processors
Authors: Cristal Adrián , Santana Oliverio J. , Valero Mateo , Martínez José F.
Published: August 2005

The continuously increasing gap between processor and memory speeds is a serious limitation to the performance achievable by future microprocessors. Currently, processors tolerate long-latency memory operations largely by maintaining a high number of in-flight instructions. In the future, this may require supporting many hundreds, or even thousands, of in-flight instructions. Unfortunately, the traditional approach of scaling up critical processor structures to provide such support is impractical at these levels, due to area, power, and cycle time constraints.In this paper we show that, in order to overcome this resource-scalability problem, the way in which critical processor resources are managed must be changed. Instead of simply upsizing the processor structures, we propose a smarter use of the available resources, supported by a selective checkpointing mechanism. This mechanism allows instructions to commit out of order, and makes a reorder buffer unnecessary. We present a set of techniques such as multilevel instruction queues, late allocation and early release of registers, and early release of load/store queue entries. All together, these techniques constitute what we call a
kilo-instruction processor
, an architecture that can support thousands of in-flight instructions, and thus may achieve high performance even in the presence of large memory access latencies.
Tolerating memory latency through push prefetching for pointer-intensive applications
Authors: Yang Chia-Lin , Lebeck Alvin R. , Tseng Hung-Wei , Lee Chien-Hao
Published: August 2005

Prefetching is often used to overlap memory latency with computation for array-based applications. However, prefetching for pointer-intensive applications remains a challenge because of the irregular memory access pattern and pointer-chasing problem. In this paper, we proposed a cooperative hardware/software prefetching framework, the push architecture, which is designed specifically for linked data structures. The push architecture exploits program structure for future address generation instead of relying on past address history. It identifies the load instructions that traverse a LDS and uses a prefetch engine to execute them ahead of the CPU execution. This allows the prefetch engine to successfully generate future addresses. To overcome the serial nature of LDS address generation, the push architecture employs a novel data movement model. It attaches the prefetch engine to each level of the memory hierarchy and
pushes
, rather than
pulls
, data to the CPU. This push model decouples the pointer dereference from the transfer of the current node up to the processor. Thus a series of pointer dereferences becomes a pipelined process rather than a serial process. Simulation results show that the push architecture can reduce up to 100% of memory stall time on a suite of pointer-intensive applications, reducing overall execution time by an average 15%.
Cheap recovery
Authors: Huang Andrew C. , Fox Armando
Published: August 2005

Cluster hash tables (CHTs) are key components of many large-scale Internet services due to their highly-scalable performance and the prevalence of the type of data they store. Another advantage of CHTs is that they can be designed to be as self-managing as a cluster of stateless servers. One key to achieving this extreme manageability is reboot-based recovery that is predictably fast and has modest impact on system performance and availability. This "cheap" recovery mechanism simplifies management in two ways. First, it simplifies failure detection by lowering the cost of acting on false positives. This enables one to use statistical techniques to turn hard-to-catch failures, such as node degradation, into failure, followed by recovery. Second, cheap recovery simplifies capacity planning by recasting repartitioning as failure plus recovery to achieve zero-downtime incremental scaling. These low-cost recovery and scaling mechanisms make it possible for the system to be continuously self-adjusting, a key property of self-managing systems.
Tunable randomization for load management in shared-disk clusters
Authors: Wu Changxun , Burns Randal
Published: August 2005

We develop and evaluate a system for load management in shared-disk file systems built on clusters of heterogeneous computers. It balances workload by moving file sets among cluster server nodes. It responds to changing server resources that arise from failure and recovery, and dynamically adding or removing servers. It also realizes performance consistency---nearly uniform performance across all servers. The system is adaptive and self-tuning. It operates without any
a priori
knowledge of workload properties, or the capabilities of the servers. Rather, it continuously tunes load placement using a technique called adaptive, nonuniform (ANU) randomization. ANU randomization realizes the scalability and metadata reduction benefits of hash-based, randomized placement techniques, while avoiding hashing's drawbacks: load skew, inability to cope with heterogeneity, and lack of tunability. ANU randomization outperforms virtual-processor approaches to load balancing, while reducing the amount of shared state among servers and the amount of load movement.
Disk scheduling in a multimedia I/O system
Authors: Reddy A. L. N. , Wyllie Jim , Wijayaratne K. B. R.
Published: August 2005

This article provides a retrospective of our original paper by the same title in the Proceedings of the First ACM Conference on Multimedia, published in 1993. This article examines the problem of disk scheduling in a multimedia I/O system. In a multimedia server, the disk requests may have constant data rate requirements and need guaranteed service. We propose a new scheduling algorithm, SCAN-EDF, that combines the features of SCAN type of seek optimizing algorithm with an Earliest Deadline First (EDF) type of real-time scheduling algorithm. We compare SCAN-EDF with other scheduling strategies and show that SCAN-EDF combines the best features of both SCAN and EDF. We also investigate the impact of buffer space on the maximum number of video streams that can be supported.We show that by making the deadlines larger than the request periods, a larger number of streams can be supported.We also describe how we extended the SCAN-EDF algorithm in the PRISM multimedia architecture. PRISM is an integrated multimedia server, designed to satisfy the QOS requirements of multiple classes of requests. Our experience in implementing the extended SCAN-EDF algorithm in a generic operating system is discussed and performance metrics and results are presented to illustrate how the SCAN-EDF extensions and implementation strategies have succeeded in meeting the QOS requirements of different classes of requests.
Structured multimedia authoring
Authors: Bulterman Dick C. A. , Hardman Lynda
Published: August 2005

Authoring context sensitive, interactive multimedia presentations is much more complex than authoring either purely audiovisual applications or text. Interactions among media objects need to be described as a set of spatio-temporal relationships that account for synchronous and asynchronous interactions, as well as on-demand linking behavior. This article considers the issues that need to be addressed by an authoring environment. We begin with a partitioning of concerns based on seven classes of authoring problems. We then describe a selection of multimedia authoring environments within four different authoring paradigms: structured, timeline, graph and scripting. We next provide observations and insights into the authoring process and argue that the structured paradigm provides the most useful framework for presentation authoring. We close with an example application of the structured multimedia authoring paradigm in the context of our own structure-based system GRiNS.
The berkeley software MPEG-1 video decoder
Authors: Mayer-Patel Ketan , Smith Brian C. , Rowe Lawrence A.
Published: August 2005

This article reprises the description of the Berkeley software-only MPEG-1 video decoder originally published in the proceedings of the 1st International ACM Conference on Multimedia in 1993. The software subsequently became widely used in a variety of research systems and commercial products. Its main impact was to provide a platform for experimenting with streaming compressed video and to expose the strengths and weaknesses of software-only video decoding using general purpose computing architectures. This article compares the original performance results with experiments run on a modern processor to demonstrate the gains of processing power in the past ten years relative to this specific application and discusses the history of MPEG-1 video software decoding and the Berkeley MPEG research group.
Throwing versus walking as indicators of distance perception in similar real and virtual environments
Authors: Sahm Cynthia S. , Creem-Regehr Sarah H. , Thompson William B. , Willemsen Peter
Published: August 2005

For humans to effectively interact with their environment, it is important for the visual system to determine the absolute size and distance of objects. Previous experiments performed in full-cue, real-world environments have demonstrated that blind walking to targets serves as an accurate indication of distance perception, up to about 25 m. In contrast, the same task performed in virtual environments (VEs) using head-mounted displays shows significant underestimation in walking. To date, blind walking is the only visually directed action task that has been used to evaluate distance perception in VEs beyond reaching distances. The possible influence of the response measure itself on absolute distance perception in virtual environments is currently an open question. Blind walking involves locomotion and the egocentric updating of the environment with one's own movement. We compared this measure to blind throwing, a task that involves the initiation of a movement directed by vision, but no further interaction within the environment. Both throwing and walking were compressed in the VE but accurate in the real world. We suggest that distance compression found in VEs may be a result of a general perceptual origin rather than specific to the response measure.
Improving human haptic performance in normal and impaired human populations through unattended activation-based learning
Authors: Dinse Hubert R. , Kalisch Tobias , Ragert Patrick , Pleger Burkhard , Schwenkreis Peter , Tegenthoff Martin
Published: August 2005

Human haptic performance is not fixed, but subject to major alterations through learning processes. We describe a new stimulation protocol that allows to improve haptic performance in humans in a highly systemic way through unattended activation-based learning. The so-called coactivation protocol is based upon temporal constraints of Hebbian learning where simultaneity plays a key role for the induction of plastic changes. We provide an overview about the potential of coactivation by summarizing recent findings showing that coactivation alters a broad range of basic as well as cognitively demanding types of haptic performance in parallel to cortical reorganization in somatosensory cortex. For example, coactivation applied to the tip of the index finger, or to all fingers of the dominant hand improves tactile acuity, but also haptic object recognition, and speeds up multiple-choice reaction times. Because such changes persist between 24 h and 1 week without further intervention, we interpret the underlying processes as a particular form of perceptual learning. We describe results where coactivation has been utilized for therapeutical purposes in impaired human populations, we outline new developments to optimize and extend unattended activation-based learning protocols, and we sketch the next steps necessary to apply the concept of unattended activation-based learning on a regular and reliable basis as a therapeutical tool in order to selectively interfere with impaired haptic performance.
Force constancy and its effect on haptic perception of virtual surfaces
Authors: Choi Seungmoon , Walker Laron , Tan Hong Z. , Crittenden Scott , Reifenberger Ron
Published: August 2005

The force-constancy hypothesis states that the user of a force-feedback device maintains a constant penetration force when stroking virtual surfaces in order to perceive their topography. The hypothesis was developed to address a real-world data perceptualization problem where the perception of surface topography was distorted when the surface stiffness was nonuniform. Two experiments were conducted. In Experiment I, we recorded the penetration depths of the probe tip while the user stroked two surfaces with equal height but different stiffness values. We found that the data could be quantitatively modeled by the force-constancy hypothesis when the virtual surfaces were neither too soft nor too hard. In Experiment II, we demonstrated that given two adjacent surfaces, their perceived height difference depended on both the surface stiffness values as well as the relative heights of the surfaces. Specifically, we showed that the higher but softer surface could be perceived to be lower, at the same height, or higher than the other surface, depending on how much higher it was than the other surface. The results were consistent with the predictions of the force-constancy hypothesis. Our findings underscore the importance of understanding the interplay of haptic rendering parameters.
Waypoint navigation with a vibrotactile waist belt
Authors: Erp Jan B. F. Van , Veen Hendrik A. H. C. Van , Jansen Chris , Dobbins Trevor
Published: August 2005

Presenting waypoint navigation on a visual display is not suited for all situations. The present experiments investigate if it is feasible to present the navigation information on a tactile display. Important design issue of the display is how direction and distance information must be coded. Important usability issues are the resolution of the display and its usefulness in vibrating environments. In a pilot study with 12 pedestrians, different distance-coding schemes were compared. The schemes translated distance to vibration rhythm while the direction was translated into vibration location. The display consisted of eight tactors around the user's waist. The results show that mapping waypoint direction on the location of vibration is an effective coding scheme that requires no training, but that coding for distance does not improve performance compared to a control condition with no distance information. In Experiment 2, the usefulness of the tactile display was shown in two case studies with a helicopter and a fast boat.
First evaluation of a novel tactile display exerting shear force via lateral displacement
Authors: Drewing Knut , Fritschi Michael , Zopf Regine , Ernst Marc O. , Buss Martin
Published: August 2005

Based on existing knowledge on human tactile movement perception, we constructed a prototype of a novel tactile multipin display that controls lateral pin displacement and, thus produces shear force. Two experiments focus on the question of whether the prototype display generates tactile stimulation that is appropriate for the sensitivity of human tactile perception. In particular, Experiment I studied human resolution for distinguishing between different directions of pin displacement and Experiment II explored the perceptual integration of information resulting from the displacement of multiple pins. Both experiments demonstrated that humans can discriminate between directions of the displacements, and also that the technically realized resolution of the display exceeds the perceptual resolution (>14°). Experiment II demonstrated that the human brain does not process stimulation from the different pins of the display independent of one another at least concerning direction. The acquired psychophysical knowledge based on this new technology will in return be used to improve the design of the display.