bluuebunny/crossref_metadata_2025 huggingface dataset:
Idletime scheduling with preemption intervals
Authors: Eggert Lars , Touch Joseph D.
Published: November 2005

This paper presents the idletime scheduler; a generic, kernel-level mechanism for using idle resource capacity in the background without slowing down concurrent foreground use. Many operating systems fail to support transparent background use and concurrent foreground performance can decrease by 50% or more. The idletime scheduler minimizes this interference by partially relaxing the work conservation principle during
preemption intervals
, during which it serves no background requests even if the resource is idle. The length of preemption intervals is a controlling parameter of the scheduler: short intervals aggressively utilize idle capacity; long intervals reduce the impact of background use on foreground performance. Unlike existing approaches to establish prioritized resource use, idletime scheduling requires only localized modifications to a limited number of system schedulers. In experiments, a FreeBSD implementation for idletime network scheduling maintains over 90% of foreground TCP throughput, while allowing concurrent, high-rate UDP background flows to consume up to 80% of remaining link capacity. A FreeBSD disk scheduler implementation maintains 80% of foreground read performance, while enabling concurrent background operations to reach 70% throughput.
FS2
Authors: Huang Hai , Hung Wanda , Shin Kang G.
Published: November 2005

Disk performance is increasingly limited by its head positioning latencies, i.e., seek time and rotational delay. To reduce the head positioning latencies, we propose a novel technique that
dynamically
places copies of data in file system's
free blocks
according to the disk access patterns observed at runtime. As one or more replicas can now be accessed in addition to their original data block, choosing the "nearest" replica that provides fastest access can significantly improve performance for disk I/O operations.We implemented and evaluated a prototype based on the popular Ext2 file system. In our prototype, since the file system layout is modified only by using the free/unused disk space (hence the name
Free Space File System
, or FS
2
), users are completely oblivious to how the file system layout is modified in the background; they will only notice performance improvements over time. For a wide range of workloads running under Linux, FS
2
is shown to reduce disk access time by 41--68% (as a result of a 37--78% shorter seek time and a 31--68% shorter rotational delay) making a 16--34% overall user-perceived performance improvement. The reduced disk access time also leads to a 40--71% energy savings per access.
THINC
Authors: Baratto Ricardo A. , Kim Leonard N. , Nieh Jason
Published: November 2005

Rapid improvements in network bandwidth, cost, and ubiquity combined with the security hazards and high total cost of ownership of personal computers have created a growing market for thin-client computing. We introduce THINC, a virtual display architecture for high-performance thin-client computing in both LAN and WAN environments. THINC virtualizes the display at the device driver interface to transparently intercept application display commands and translate them into a few simple low-level commands that can be easily supported by widely used client hardware. THINC's translation mechanism efficiently leverages display semantic information through novel optimizations such as offscreen drawing awareness, native video support, and server-side screen scaling. This is integrated with an update delivery architecture that uses shortest command first scheduling and non-blocking operation. THINC leverages existing display system functionality and works seamlessly with unmodified applications, window systems, and operating systems.We have implemented THINC in an X/Linux environment and compared its performance against widely used commercial approaches, including Citrix MetaFrame, Microsoft RDP, GoToMyPC, X, NX, VNC, and Sun Ray. Our experimental results on web and audio/video applications demonstrate that THINC can provide up to 4.8 times faster web browsing performance and two orders of magnitude better audio/video performance. THINC is the only thin client capable of transparently playing full-screen video and audio at full frame rate in both LAN and WAN environments. Our results also show for the first time that thin clients can even provide good performance using remote clients located in other countries around the world.
Taxonomy generation for text segments
Authors: Chuang Shui-Lung , Chien Lee-Feng
Published: November 2005

It is crucial in many information systems to organize short text segments, such as keywords in documents and queries from users, into a well-formed taxonomy. In this article, we address the problem of taxonomy generation for diverse text segments with a general and practical approach that uses the Web as an additional knowledge source. Unlike long documents, short text segments typically do not contain enough information to extract reliable features. This work investigates the possibilities of using highly ranked search-result snippets to enrich the representation of text segments. A hierarchical clustering algorithm is then designed for creating the hierarchical topic structure of text segments. Text segments with close concepts can be grouped together in a cluster, and relevant clusters linked at the same or near levels. Different from traditional clustering algorithms, which tend to produce cluster hierarchies with a very unnatural shape, the algorithm tries to produce a more natural and comprehensive tree hierarchy. Extensive experiments were conducted on different domains of text segments, including subject terms, people names, paper titles, and natural language questions. The obtained experimental results have shown the potential of the proposed approach, which provides a basis for the in-depth analysis of text segments on a larger scale and is believed able to benefit many information systems.
Set-based vector model
Authors: Pôssas Bruno , Ziviani Nivio , Meira Wagner , Ribeiro-Neto Berthier
Published: November 2005

This work presents a new approach for ranking documents in the vector space model. The novelty lies in two fronts. First, patterns of term co-occurrence are taken into account and are processed efficiently. Second, term weights are generated using a data mining technique called association rules. This leads to a new ranking mechanism called the
set-based vector model
. The components of our model are no longer index terms but index termsets, where a termset is a set of index terms. Termsets capture the intuition that semantically related terms appear close to each other in a document. They can be efficiently obtained by limiting the computation to small passages of text. Once termsets have been computed, the ranking is calculated as a function of the termset frequency in the document and its scarcity in the document collection. Experimental results show that the set-based vector model improves average precision for all collections and query types evaluated, while keeping computational costs small. For the 2-gigabyte TREC-8 collection, the set-based vector model leads to a gain in average precision figures of 14.7% and 16.4% for disjunctive and conjunctive queries, respectively, with respect to the standard vector space model. These gains increase to 24.9% and 30.0%, respectively, when proximity information is taken into account. Query processing times are larger but, on average, still comparable to those obtained with the standard vector model (increases in processing time varied from 30% to 300%). Our results suggest that the set-based vector model provides a correlation-based ranking formula that is effective with general collections and computationally practical.
Evolution of web site design patterns
Authors: Ivory Melody Y. , Megraw Rodrick
Published: November 2005

The Web enables broad dissemination of information and services; however, the ways in which sites are designed can either facilitate or impede users' benefit from these resources. We present a longitudinal study of web site design from 2000 to 2003. We analyze over 150 quantitative measures of interface aspects (e.g., amount of text on pages, numbers and types of links, consistency, accessibility, etc.) for 22,000 pages and over 1,500 sites that received ratings from Internet professionals. We examine characteristics of highly rated sites and provide three perspectives on the evolution of web site design patterns: (1) descriptions of design patterns during each time period; (2) changes in design patterns across the three time periods; and (3) comparisons of design patterns to those that are recommended in the relevant literature (i.e., texts by recognized experts and user studies). We illustrate how design practices conform to or deviate from recommended practices and the consequent implications. We show that the most glaring deficiency of web sites, even for sites that are highly rated, is their inadequate accessibility, in particular for browser scripts, tables, and form elements.
Beta-connection
Authors: Nonato Luis Gustavo , Cuadros-Vargas Alex Jesus , Minghim Rosane , De Oliveira Maria Cristina F.
Published: November 2005

Despite the significant evolution of techniques for 3D-reconstruction from planar cross sections, establishing the correspondence of regions in adjacent slices remains an important issue. In this article, we propose a novel approach for solving the correspondence problem in a flexible manner. We show that from the 3D Delaunay triangulation, it is possible to derive a distance measure among regions lying in adjacent slices. Such distance is used to define a positive integer parameter, called β, responsible for establishing the connections. Varying β thus allows the construction of different models from a given set of cross-sectional regions: small values of β causes closer regions to be connected into a single component, and as β increases, more distant regions are connected together. The algorithm, named β-connection, is described, and examples are provided that illustrate its applicability in solid modeling and model reconstruction from real data. The underlying reconstruction method is effective, which jointly with the β-connection correspondence strategy, improve the usability of volumetric reconstruction techniques considerably.
Algebraic analysis of high-pass quantization
Authors: Chen Doron , Cohen-Or Daniel , Sorkine Olga , Toledo Sivan
Published: November 2005

This article presents an algebraic analysis of a mesh-compression technique called
high-pass quantization
[Sorkine et al. 2003]. In high-pass quantization, a rectangular matrix based on the mesh topological Laplacian is applied to the vectors of the Cartesian coordinates of a polygonal mesh. The resulting vectors, called δ-coordinates, are then quantized. The applied matrix is a function of the topology of the mesh and the indices of a small set of mesh vertices (anchors) but not of the location of the vertices. An approximation of the geometry can be reconstructed from the quantized δ-coordinates and the spatial locations of the anchors. In this article, we show how to algebraically bound the reconstruction error that this method generates. We show that the small singular value of the transformation matrix can be used to bound both the quantization error and the rounding error which is due to the use of floating-point arithmetic. Furthermore, we prove a bound on this singular value. The bound is a function of the topology of the mesh and of the selected anchors. We also propose a new anchor-selection algorithm, inspired by this bound. We show experimentally that the method is effective and that the computed upper bound on the error is not too pessimistic.
Expressive speech-driven facial animation
Authors: Cao Yong , Tien Wen C. , Faloutsos Petros , Pighin Frédéric
Published: November 2005

Speech-driven facial motion synthesis is a well explored research topic. However, little has been done to model expressive visual behavior during speech. We address this issue using a machine learning approach that relies on a database of speech-related high-fidelity facial motions. From this training set, we derive a generative model of expressive facial motion that incorporates emotion control, while maintaining accurate lip-synching. The emotional content of the input speech can be manually specified by the user or automatically extracted from the audio signal using a Support Vector Machine classifier.
Learning silhouette features for control of human motion
Authors: Ren Liu , Shakhnarovich Gregory , Hodgins Jessica K. , Pfister Hanspeter , Viola Paul
Published: November 2005

We present a vision-based performance interface for controlling animated human characters. The system interactively combines information about the user's motion contained in silhouettes from three viewpoints with domain knowledge contained in a motion capture database to produce an animation of high quality. Such an interactive system might be useful for authoring, for teleconferencing, or as a control interface for a character in a game. In our implementation, the user performs in front of three video cameras; the resulting silhouettes are used to estimate his orientation and body configuration based on a set of discriminative local features. Those features are selected by a machine-learning algorithm during a preprocessing step. Sequences of motions that approximate the user's actions are extracted from the motion database and scaled in time to match the speed of the user's motion. We use swing dancing, a complex human motion, to demonstrate the effectiveness of our approach. We compare our results to those obtained with a set of global features, Hu moments, and ground truth measurements from a motion capture system.
Automatic restoration of polygon models
Authors: Bischoff Stephan , Pavic Darko , Kobbelt Leif
Published: November 2005

We present a fully automatic technique which converts an inconsistent input mesh into an output mesh that is guaranteed to be a clean and consistent mesh representing the closed manifold surface of a solid object. The algorithm removes all typical mesh artifacts such as degenerate triangles, incompatible face orientation, non-manifold vertices and edges, overlapping and penetrating polygons, internal redundant geometry, as well as gaps and holes up to a user-defined maximum size ρ. Moreover, the output mesh always stays within a prescribed tolerance ε to the input mesh. Due to the effective use of a hierarchical octree data structure, the algorithm achieves high voxel resolution (up to 4096
3
on a 2GB PC) and processing times of just a few minutes for moderately complex objects. We demonstrate our technique on various architectural CAD models to show its robustness and reliability.
Physically-based simulation of twilight phenomena
Authors: Haber Jörg , Magnor Marcus , Seidel Hans-Peter
Published: November 2005

We present a physically-based approach to compute the colors of the sky during the twilight period before sunrise and after sunset. The simulation is based on the theory of light scattering by small particles. A realistic atmosphere model is assumed, consisting of air molecules, aerosols, and water. Air density, aerosols, and relative humidity vary with altitude. In addition, the aerosol component varies in composition and particle-size distribution. This allows us to realistically simulate twilight phenomena for a wide range of different climate conditions. Besides considering multiple Rayleigh and Mie scattering, we take into account wavelength-dependent refraction of direct sunlight as well as the shadow of the Earth. Incorporating several optimizations into the radiative transfer simulation, a photo-realistic hemispherical twilight sky is computed in less than two hours on a conventional PC. The resulting radiometric data is useful, for instance, for high-dynamic range environment mapping, outdoor global illumination calculations, mesopic vision research and optical aerosol load probing.
Hierarchical triangular splines
Authors: Yvart Alex , Hahmann Stefanie , Bonneau Georges-Pierre
Published: November 2005

Smooth parametric surfaces interpolating triangular meshes are very useful for modeling surfaces of arbitrary topology. Several interpolants based on these kind of surfaces have been developed over the last fifteen years. However, with current 3D acquisition equipments, models are becoming more and more complex. Since previous interpolation methods lack a local refinement property, there is no way to locally adapt the level of detail. In this article, we introduce a hierarchical triangular surface model. The surface is overall tangent plane continuous and is defined parametrically as a piecewise quintic polynomial. It can be adaptively refined while preserving the overall tangent plane continuity. This model enables designers to create a complex smooth surface of arbitrary topology composed of a small number of patches to which details can be added by locally refining the patches until an arbitrary small size is reached. It is implemented as a hierarchical data structure where the top layer describes a coarse, smooth base surface and the lower levels encode the details in local frame coordinates.
Low-complexity maximum intensity projection
Authors: Mora Benjamin , Ebert David S.
Published: November 2005

Many techniques have already been proposed to improve the efficiency of maximum intensity projection (MIP) volume rendering, but none of them considered the possible hypothesis of a better complexity than either O(
n
) for finding the maximum value of
n
samples along a ray or O(
n
3
) for an object-order algorithm. Here, we fully model and analyze the use of octrees for MIP, and we mathematically show that the average MIP complexity can be reduced to O(
n
2
) for an object-order algorithm, or to O(log(
n
)) per ray when using the image-order variant of our algorithm. Therefore, this improvement establishes a major advance for interactive MIP visualization of large-volume data.In parallel, we also present an object-order implementation of our algorithm, satisfying the theoretical O(
n
2
) result. It is based on hierarchical occlusion maps that perform on-the-fly visibility of the data, and our results show that it is the most efficient solution for MIP available to date.
The irregular Z-buffer
Authors: Johnson Gregory S. , Lee Juhyun , Burns Christopher A. , Mark William R.
Published: November 2005

The classical Z-buffer visibility algorithm samples a scene at regularly spaced points on an image plane. Previously, we introduced an extension of this algorithm called theirregular Z-bufferthat permits sampling of the scene from arbitrary points on the image plane. These sample points are stored in a two-dimensional spatial data structure. Here we present a set of architectural enhancements to the classical Z-buffer acceleration hardware which supports efficient execution of the irregular Z-buffer. These enhancements enable efficient parallel construction and query of certain irregular data structures, including the grid of linked lists used by our algorithm. The enhancements include flexible atomic read-modify-write units located near the memory controller, an internal routing network between these units and the fragment processors, and a MIMD fragment processor design. We simulate the performance of this new architecture and demonstrate that it can be used to render high-quality shadows in geometrically complex scenes at interactive frame rates. We also discuss other uses of the irregular Z-buffer algorithm and the implications of our architectural changes in the design of chip-multiprocessors.
It's time to think outside the computational box
Authors: Kugel Peter
Published: November 2005

Systems that don't announce when they've reached their final results can `compute' the uncomputable, possibly allowing them to understand their users and generate their own programs from examples.
Mobile cookies management on a smart card
Authors: Chan Alvin T. S.
Published: November 2005

With CookiesCard, cookies are stored on users' smart cards, coupling cookies to users, not to their machines.
Call for a public-domain SpeechWeb
Authors: Frost Richard A.
Published: November 2005

All that's missing is innovative use of existing technology and the encouragement of public participation.
Rule of law and the international diffusion of e-commerce
Authors: Shih Chuan-Fong , Dedrick Jason , Kraemer Kenneth L.
Published: November 2005

Strong institutional environments serve as a foundation for e-commerce growth opportunities.
Assessing the relative influence of journals in a citation network
Authors: Nerur Sridhar , Sikora Riyaz , Mangalaraj George , Balijepally VenuGopal
Published: November 2005

Some journals are perceived as sources of knowledge; others serve as storers of knowledge. Learning the strengths and persuasions of journals is of value to academia, scholars, and publishers.
An architecture for distributed scenario building and evaluation
Authors: Wild Rosemary H. , Griggs Kenneth A. , Li Eldon Y.
Published: November 2005

A Web portal can support collaborative learning and help individuals and organizations plan for an uncertain future.
Using web-based search data to predict macroeconomic statistics
Authors: Ettredge Michael , Gerdes John , Karuga Gilbert
Published: November 2005

Tracking common search terms used on the Web can produce accurate, useful statistics about the unemployment rate. We hope to extend this approach to other economic statistics.
Recentering computer science
Authors: Denning Peter J. , McGettrick Andrew
Published: November 2005

The recent decreases of enrollment in computer science programs signal a chasm between our historical emphasis on programming and the contemporary concerns of those choosing careers.
The plot to deskill software engineering
Authors: Glass Robert L.
Published: November 2005

Do software engineering milestones represent creativity-enhancing or creativity-stifling developments?
Rescuing our families, our neighbors, and ourselves
Authors: Patterson David A.
Published: November 2005

Should computer scientists and engineers take on a greater responsibility to help reduce the loss of life and property damage from natural disasters?
Software process improvement
Authors: Hardgrave Bill C. , Armstrong Deborah J.
Published: November 2005

Realizing the benefits of continuous software process improvement.
Realizing the benefits of user-level channel diversity
Authors: Vergetis Evangelos , Guérin Roch , Sarkar Saswati
Published: November 2005

Channel or path diversity is known to improve performance in physical layer designs, channel access strategies, path switching mechanisms, etc. In this paper, we focus on "user-level" mechanisms that operate simply by distributing packet transmissions across multiple channels. We seek to understand when, why, and to what extent this can be of benefit, and equally important, whether these benefits can be realized with as little of an added cost as possible. In that context, our main contribution is not so much in identifying optimal policies for leveraging channel diversity, but in introducing the concept of channel "equivalence" and demonstrating that channel diversity yields substantial benefits mostly when channels are approximately equivalent. We build on this finding to investigate the robustness of these improvements against errors in the characterization of the available channels or changes in their characteristics. We also explore the sensitivity of the results as the number of available channels varies. The findings of the paper demonstrate that by allowing packet transmissions from multiple users to intelligently share channels, it is possible to improve overall performance and robustness through simple and portable user-level mechanisms.
A clean slate 4D approach to network control and management
Authors: Greenberg Albert , Hjalmtysson Gisli , Maltz David A. , Myers Andy , Rexford Jennifer , Xie Geoffrey , Yan Hong , Zhan Jibin , Zhang Hui
Published: November 2005

Today's data networks are surprisingly fragile and difficult to manage. We argue that the root of these problems lies in the complexity of the control and management planes--the software and protocols coordinating network elements--and particularly the way the decision logic and the distributed-systems issues are inexorably intertwined. We advocate a complete refactoring of the functionality and propose three key principles--network-level objectives, network-wide views, and direct control--that we believe should underlie a new architecture. Following these principles, we identify an extreme design point that we call "4D," after the architecture's four planes: decision, dissemination, discovery, and data. The 4D architecture completely separates an AS's decision logic from pro-tocols that govern the interaction among network elements. The AS-level objectives are specified in the decision plane, and en-forced through direct configuration of the state that drives how the data plane forwards packets. In the 4D architecture, the routers and switches simply forward packets at the behest of the decision plane, and collect measurement data to aid the decision plane in controlling the network. Although 4D would involve substantial changes to today's control and management planes, the format of data packets does not need to change; this eases the deployment path for the 4D architecture, while still enabling substantial innovation in network control and management. We hope that exploring an extreme design point will help focus the attention of the research and industrial communities on this crucially important and intellectually challenging area.
The IETF, the IRTF, and the networking research community
Authors: Falk Aaron
Published: November 2005

Some in the research community perceive the Internet Engineering Task Force (IETF) as ossified and see the difficulty in standardizing new protocols as an indication that there is no room for research in the Internet or researchers in the IETF. The truth of the matter is a growing number of critical research problems are facing the Internet today, and the IETF needs help from the network research community. Research Groups in the Internet Research Task Force (IRTF) are working on some ofthese important problems. The networking research comm nity is invited to collaborate on an effort which will have great impact on current and future network functions.
DIMES
Authors: Shavitt Yuval , Shir Eran
Published: November 2005

Today's Internet maps, which are all collected from a small number of vantage points, are falling short of being accurate. We suggest here a paradigm shift for this task. DIMES is a distributed measurement infrastructure for the Internet that is based on the deployment of thousands of light weight measurement agents around the globe. We describe the rationale behind DIMES deployment, discuss its design trade-offs and algorithmic challenges, and analyze the structure of the Internet as it seen with DIMES.
The open network laboratory
Authors: DeHart John , Kuhns Fred , Parwatikar Jyoti , Turner Jonathan , Wiseman Charlie , Wong Ken
Published: November 2005

The
Open Network Laboratory
(ONL) is a remotely accessible network testbed designed to enable networking faculty, students and researchers to conduct experiments using high performance routers and applications. The system is built around a set of extensible, high-performance routers and has a graphical interface that enables users to easily configure and run experiments remotely. ONL's
Remote Laboratory Interface
(RLI) allows users to easily configure a network topology, configure routes and packet filters in the routers, assign flows or flow aggregates to separate queues with configurable QoS and attach hardware monitoring points to real-time charts. The remote visualization features of the RLI make it easy to directly view the effects of traffic as it moves through a router, allowing the user to gain better insight into system behavior and create compelling demonstrations. Each port of the router is equipped with an embedded processor that provides a simple environment for software
plugins
allowing users to extend the system's functionality. This paper describes the general facilties and some networking experiments that can be carried out. We hope that you and your collegues and students will check out the facility and register for an account at our web site onl.arl.wustl.edu
BGP routing changes
Authors: Teixeira Renata , Agarwal Sharad , Rexford Jennifer
Published: November 2005

Large ISPs experience millions of BGP routing changes a day. In this paper, we discuss the impact of BGP routing changes on the flow of trafffic, summarizing and reconciling the results from six measurement studies of the Sprint and AT&T backbone networks.
Large scale content distribution protocols
Authors: Neumann Christoph , Roca Vincent , Walsh Rod
Published: November 2005

This paper introduces large scale content distribution protocols, which are capable of scaling to massive numbers of users and providing low delay end-to-end delivery. Delivery of files and static objects is described, with real-time content streaming being outside the scope of this paper. The focus is on solutions provided by the IETF Reliable Multicast Transport Working Group. More precisely, the paper explains FLUTE, ALC and the associated building blocks. Then it discusses how these components are used in the Multimedia Broadcast Multicast Service (MBMS) for 3G systems and in the IP Datacast (IPDC) service for Digital Video Broadcast for Handheld devices (DVB-H).
The internet measurement data catalog
Authors: Shannon Colleen , Moore David , Keys Ken , Fomenkov Marina , Huffaker Bradley , claffy k
Published: November 2005

Internet data remains one of the basic components of computer science network research. Despite its necessity, available data is limited by legal, social, and technical constraints on its collection and distribution. Thus, optimal distribution of knowledge about available data is a valuable service to the research community. To this end, CAIDA has developed the Internet Measurement Data Catalog to:

provide a searchable index of available data

enhance documentation of datasets via a public annotation system

advance network science by promoting reproducible research

This paper describes the impetus, design, and planned deployment of the Internet Measurement Data Catalog.
Designers and the age of fear
Authors: Thackara John
Published: November 2005

Looking into the---sometimes bad---reality of life offers rich challenges for interaction design. In this Connections column, John Thackara looks into the aspects of fear and discusses its relevance for human-computer interaction.---Manfred Tscheligi
Minding your user's business
Authors: Jones Peter H.
Published: November 2005

In many professions, the right balance between generalist and specialist skills is difficult to find. In UCD, we need to distinguish between method specialization and domain specialization, both of which have their own sets of pros and cons. Many internal UCD staff tend to be de facto domain specialists, simply because they naturally focus on the business domain of their employer. In this column, Peter Jones argues the case for an increased emphasis on domain specialization for external consultants as well. Any generalists out there want to take the other side?---David Siegel and Susan Dray
Small world, water coolers, and the challenge of remote collaboration
Authors: Gorlenko Lada
Published: November 2005

Ah, the water cooler. No other element of the office environment conjures up such visions of camaraderie and congeniality as does the water cooler (or its equivalent; when I worked in Italy, we chatted by---of course---the espresso machine). Often a centerpiece of cartoons and anecdotes, the water cooler has come to symbolize the social glue that holds our professional interactions together and helps the collaborative culture function. Around it we may temporarily drop the subject at hand and get to know one another as human beings.

So how do we feel when a professional collaborative environment has no water cooler to facilitate the culture? What do we do? How do we develop relationships and come to trust our colleagues? Lada Gorlenko explores her reactions and what she decided to do about it, and urges us to accept the challenge for ourselves.

---Elizabeth Buie
Social matching
Authors: Terveen Loren , McDonald David W.
Published: November 2005

Social matching systems bring people together in both physical and online spaces. They have the potential to increase social interaction and foster collaboration. However, social matching systems lack a clear intellectual foundation: the nature of the design space, the key research challenges, and the roster of appropriate methods are all ill-defined. This article begins to remedy the situation. It clarifies the scope of social matching systems by distinguishing them from other recommender systems and related systems and techniques. It identifies a set of issues that characterize the design space of social matching systems and shows how existing systems explore different points within the design space. It also reviews selected social science results that can provide input into system design. Most important, the article presents a research agenda organized around a set of claims. The claims embody our understanding of what issues are most important to investigate, our beliefs about what is most likely to be true, and our suggestions of specific research directions to pursue.
A probabilistic approach to modeling two-dimensional pointing
Authors: Grossman Tovi , Balakrishnan Ravin
Published: November 2005

We investigate and model two-dimensional pointing where the target distance and size vary as does the angle of movement. We first study the spread of hits in a rapid approximate pointing task at varied distances and movement angles. Consistent with the literature, our results show that the spread of hits along the movement direction deviate more than the spread of hits in the direction perpendicular to movement, and both spreads increase with distance. Based on the distribution of this spread of hits, we propose and validate a new probabilistic model that describes two-dimensional pointing. Unlike previous models, our model accounts for more variables of two-dimensional pointing and can be generalized to any target shape, size, orientation, location, and dimension. In contrast to previous work, which suggests that target height has minimal impact on performance when it is larger than the width, our results show that, even when height is greater than width, it can significantly impact movement time.
CBS domains: structure, function, and pathology in human proteins
Authors: Ignoul Sofie , Eggermont Jan
Published: November 2005

The cystathionine-β-synthase (CBS) domain is an evolutionarily conserved protein domain that is present in the proteome of archaebacteria, prokaryotes, and eukaryotes. CBS domains usually come in tandem repeats and are found in cytosolic and membrane proteins performing different functions (metabolic enzymes, kinases, and channels). Crystallographic studies of bacterial CBS domains have shown that two CBS domains form an intramolecular dimeric structure (CBS pair). Several human hereditary diseases (homocystinuria, retinitis pigmentosa, hypertrophic cardiomyopathy, myotonia congenital, etc.) can be caused by mutations in CBS domains of, respectively, cystathionine-β-synthase, inosine 5′-monophosphate dehydrogenase, AMP kinase, and chloride channels. Despite their clinical relevance, it remains to be established what the precise function of CBS domains is and how they affect the structural and/or functional properties of an enzyme, kinase, or channel. Depending on the protein in which they occur, CBS domains have been proposed to affect multimerization and sorting of proteins, channel gating, and ligand binding. However, recent experiments revealing that CBS domains can bind adenosine-containing ligands such ATP, AMP, or S-adenosylmethionine have led to the hypothesis that CBS domains function as sensors of intracellular metabolites.
Myosin filament assembly in an ever-changing myofilament lattice of smooth muscle
Authors: Seow Chun Y.
Published: November 2005

A major development in smooth muscle research in recent years is the recognition that the myofilament lattice of the muscle is malleable. The malleability appears to stem from plastic rearrangement of contractile and cytoskeletal filaments in response to stress and strain exerted on the muscle cell, and it allows the muscle to adapt to a wide range of cell lengths and maintain optimal contractility. Although much is still poorly understood, we have begun to comprehend some of the basic mechanisms underlying the assembly and disassembly of contractile and cytoskeletal filaments in smooth muscle during the process of adaptation to large changes in cell geometry. One factor that likely facilitates the plastic length adaptation is the ability of myosin filaments to form and dissolve at the right place and the right time within the myofilament lattice. It is proposed herein that formation of myosin filaments in vivo is aided by the various filament-stabilizing proteins, such as caldesmon, and that the thick filament length is determined by the dimension of the actin filament lattice. It is still an open question as to how the dimension of the dynamic filament lattice is regulated. In light of the new perspective of malleable myofilament lattice in smooth muscle, the roles of many smooth muscle proteins could be assigned or reassigned in the context of plastic reorganization of the contractile apparatus and cytoskeleton.
“Phosphatonins” and the regulation of phosphorus homeostasis
Authors: Berndt Theresa J. , Schiavi Susan , Kumar Rajiv
Published: November 2005

Phosphate ions are critical for normal bone mineralization, and phosphate plays a vital role in a number of other biological processes such as signal transduction, nucleotide metabolism, and enzyme regulation. The study of rare disorders associated with renal phosphate wasting has resulted in the discovery of a number of proteins [fibroblast growth factor 23 (FGF-23), secreted frizzled related protein 4 (sFRP-4), matrix extracellular phosphoglycoprotein, and FGF 7 (FGF-7)] that decrease renal sodium-dependent phosphate transport in vivo and in vitro. The “phosphatonins,” FGF-23 and sFRP-4, also inhibit the synthesis of 1α,25-dihydroxyvitamin D, leading to decreased intestinal phosphate absorption and further reduction in phosphate retention by the organism. In this review, we discuss the biological properties of these proteins, alterations in their concentrations in various clinical disorders, and their possible physiological role.
The Metabolic Syndrome and Type 2 Diabetes: Epidemiological Figures and Country Specificities
Authors: Procopiou Michel , Philippe Jacques
Published: November 2005

Over the last 20 years, the prevalence of the metabolic syndrome has steadily increased in all populations worldwide, changing slowly the phenotype of the human race and potentially our concept of physiological normality. Our affluent phenotype reflects progressive adaptation to the external environment, which in turn changes the standards of the metabolic variables such as body weight, blood pressure, lipid values and glucose homeostasis. The human survivors of the difficult times of the hunter-gatherer period have probably benefited from genes which have allowed for more efficient food utilization, fat deposition and weight gain, a concept referred to as the ‘thrifty gene’ hypothesis. This genetic background has now become detrimental in our society of high energy consumption, little physical activity and lifestyles that favour stress and anxiety. These genetic and environmental interactions explain the explosion in the prevalence of the metabolic syndrome and diabetes. If future estimates for the number of patients with diabetes and impaired glucose tolerance are valid, this will have a major and adverse impact on the number of stroke patients globally.
Acute Stroke and Diabetes
Authors: Lees Kennedy R. , Walters Matthew R.
Published: November 2005

Diabetes and hyperglycaemia are each over-represented amongst patients with acute stroke. Hyperglycaemia is associated with poor stroke outcome. Symptomatic intracranial haemorrhagic transformation is commoner in diabetes and hyperglycaemia but the treatment effect of thrombolysis appears not to be influenced by blood sugar level. Evidence from general patients treated in intensive care units suggests that intensive control of hyperglycaemia may improve early outcome; this evidence cannot be directly extrapolated to patients with acute stroke since supportive randomized controlled trial evidence describing benefits and risks of insulin administration for hyperglycaemia in stroke is scant. Nevertheless, at present the European guidelines suggest that glucose control may be advisable and place a threshold of 10 mmol/l for definite intervention; American guidelines are weaker. Glucose-potassium-insulin infusion or adjusted insulin infusions each have their proponents: both are effective but both carry a small risk of hypoglycaemia. Use of a suitable locally approved regimen seems advisable.
Secondary Prevention of Stroke with Antiplatelet Agents in Patients with Diabetes mellitus
Authors: Piechowski-Jozwiak Bartlomiej , Maulaz Alexander , Bogousslavsky Julien
Published: November 2005

The prevalence of diabetes mellitus (DM) varies from 1.2 to 13.3% in the general population. The most frequent is type 2 (non-insulin-dependent) DM, which constitutes 90–95% of all cases. DM increases the risk of cardiac disease, stroke, retinopathy, nephropathy, neuropathy and gangrene, and the disease is associated with an increased prevalence of other cardiovascular risk factors such as hypertension, hypercholesterolaemia, asymptomatic carotid artery disease, and obesity. The risk of stroke may be directly and indirectly increased by the presence of DM. Epidemiological data show that DM independently amplifies the risk of ischaemic stroke from 1.8- up to 6-fold, so that prevention of cardiovascular risk in diabetics is of utmost importance. The main goal is to control glycaemia, although it has never been shown to be beneficial in stroke patients. Other preventive strategies include antiplatelet treatment. The open-label Primary Prevention Project trial tested the efficacy of low-dose acetylsalicylic acid (ASA) in prevention of ischaemic events in high-risk patients, but failed to demonstrate a significant benefit of ASA in diabetic patients. However, in the CAPRIE trial, the benefit of clopidogrel was amplified in patients with DM versus those without DM in preventing ischaemic events. This difference was even more striking when comparing patients treated with insulin versus non-diabetics. Another trial – MATCH – tested the benefit of adding ASA to clopidogrel versus clopidogrel alone in the prevention of ischaemic events in high-risk cerebrovascular patients, two-thirds of whom had DM. Further research is needed to clarify the effects of different antiplatelet regimens in stroke prevention in diabetic patients, who should be considered as high vascular-risk patients.
Prevention of Stroke in Patients with Diabetes mellitus and the Metabolic Syndrome
Authors: Rothwell Peter M.
Published: November 2005

The basic principles of stroke prevention are the same in patients with diabetes and/or the metabolic syndrome as in those without. Blood-pressure lowering is highly effective in both primary and secondary prevention of stroke in diabetics, and there is no evidence to suggest that the benefits of lipid-lowering therapy are any less. Antiplatelet agents are effective in secondary prevention and may be indicated in asymptomatic diabetic patients, who have a substantially increased risk of acute vascular events. Uncertainty over optimal management of patients with diabetes, and possibly of those with metabolic syndrome, relates more to the thresholds for initiation of treatment. The decision to initiate treatment should depend on the balance between the absolute risk of potentially preventable events and the risks of any complications of treatment. The absolute risks of ischaemic stroke and acute coronary events are significantly increased in diabetics in population-based cohort studies and the recommended thresholds for instigating blood pressure lowering and lipid lowering are therefore lower than in the general population. Optimization of strategies to prevent vascular complications must be a priority, given the rapid rises in the incidence and prevalence of type 2 diabetes and the metabolic syndrome in most populations across the globe.
Genistein, a Phytoestrogen, Attenuates Monocrotaline-Induced Pulmonary Hypertension
Authors: Homma Noriyuki , Morio Yoshiteru , Takahashi Hideki , Yamamoto Akihito , Suzuki Tsutomu , Sato Koichi , Muramatsu Masashi , Fukuchi Yoshinosuke
Published: November 2005

Background: Pulmonary hypertension is characterized by high pulmonary blood pressure, vascular remodeling, and right ventricular hypertrophy. Although recent studies suggest that an imbalance between endothelial mediators on pulmonary vasculature may contribute to the development of pulmonary hypertension, the pathogenesis is not fully understood and the treatment of pulmonary hypertension is still unresolved. Objective: The purpose of this study was to investigate whether genistein, a phytoestrogen derived from soybean, would prevent the development of monocrotaline (MCT)-induced pulmonary hypertension in rats. Hemodynamic parameters of catheterized rats and morphological feature of lungs were evaluated among MCT-treated rats receiving or not receiving genistein. Furthermore, examination of expression in endothelial nitric oxide synthase and endothelin-1 peptide level was performed. Methods: Daily supplementation with either genistein (0.2 mg/kg) or vehicle was started 2 days prior to a single-dose injection of MCT (60 mg/kg). On day 28, rats underwent catheterization, and right ventricular hypertrophy and morphological features were assessed. Furthermore, endothelial nitric oxide synthase and endothelin-1 were examined by Western blot analysis and radioimmunoassay, respectively, in homogenated lungs. Results: In rats that received daily supplementation of genistein, mean pulmonary arterial pressure was significantly reduced, whereas mean systemic arterial pressure and heart rate were unaltered compared with MCT control rats on day 28 after MCT injection. Right ventricular hypertrophy, medial wall thickness of pulmonary arteries corresponding to the terminal bronchioles, and the degree of neomuscularization of more distal arteries were less severe in genistein-treated rats. Genistein supplementation improved MCT-induced downregulation of expression of endothelial nitric oxide synthase in the lungs. However, endothelin-1 peptide levels did not differ among all groups of lungs. Conclusions: We conclude that daily supplementation of genistein potently attenuates MCT-induced pulmonary hypertension, right ventricular hypertrophy, and pulmonary vascular remodeling in rats. The underlying mechanism responsible for this effect may be partly related to the restoration of a decreased expression of endothelial nitric oxide synthase.