bluuebunny/crossref_metadata_2025 huggingface dataset:
ADAPTIVE FULL STATE HYBRID PROJECTIVE SYNCHRONIZATION IN THE UNIFIED CHAOTIC SYSTEM
Authors: WANG XINGYUAN , SONG JUNMEI
Published: June 2009

This paper studies the adaptive full state hybrid projective synchronization method. Based on the Lyapunov stability theory, an adaptive controller is designed. It is proved theoretically that the controller can make the states of the dynamical system and the response system with known or unknown parameters asymptotically full state hybrid projective synchronized. A unified chaotic system is used as an example and numerical simulations show the effectiveness of the scheme.
GLOBAL WEAK SOLUTIONS OF AN INITIAL BOUNDARY VALUE PROBLEM FOR SCREW PINCHES IN PLASMA PHYSICS
Authors: ZHANG JIANWEN , JIANG SONG , XIE FENG
Published: June 2009

This paper is concerned with an initial-boundary value problem for screw pinches arisen from plasma physics. We prove the global existence of weak solutions to this physically very important problem. The main difficulties in the proof lie in the presence of 1/x-singularity in the equations at the origin and the additional nonlinear terms induced by the magnetic field. Solutions will be obtained as the limit of the approximate solutions in annular regions between two cylinders. Under certain growth assumption on the heat conductivity, we first derive a number of regularities of the approximate physical quantities in the fluid region, as well as a lot of uniform integrability in the entire spacetime domain. By virtue of these estimates we then argue in a similar manner as that in Ref. 20 to take the limit and show that the limiting functions are indeed a weak solution which satisfies the mass, momentum and magnetic field equations in the entire spacetime domain in the sense of distributions, but satisfies the energy equation only in the compact subsets of the fluid region. The analysis in this paper allows the possibility that energy is absorbed into the origin, i.e. the total energy be possibly lost in the limit as the inner radius goes to zero.
COEXISTENCE AND ASYMPTOTIC PERIODICITY IN A COOPERATING MODEL
Authors: GAN WENZHEN , LIN ZHIGUI
Published: June 2009

In this paper, the cooperating two-species Lotka–Volterra model is discussed. The authors study the existence of solutions to a strongly coupled elliptic system with homogeneous Dirichlet boundary conditions and consider the existence, stability, and global attractivity of time-periodic solutions for a coupled parabolic equations in a bounded domain. Their results show that this model possesses at least one coexistence state if cross-diffusions are weak. The existence of the positive T-periodic solutions, the local stability, and the global attractivity for the parabolic system are also given.
EXPRESSION PROFILES OF THE CELL MIGRATION-ASSOCIATED GENES DURING RAT LIVER REGENERATION
Authors: LI HONGLEI , CHEN XIAOGUANG , ZHANG FUCHUN , MA JI , XU CUNSHUAN
Published: June 2009

Cell migration plays the essential role in embryogenesis, wound healing, immunization, infection, and cancer metastasis. To study actions of cell migration-associated genes in liver regeneration, these genes were obtained by seaching for the related databases and literatures, and comprehensive analysis for the gene expression change during the regenerating process in liver was detected by Rat Genome 230 2.0 array, and identification of the LR-associated genes was through comparing the discrepancy in gene expression between sham operation and partial hepatectomy groups. The initially and totally expressed numbers of these genes in the initial phase of LR, G0/G1 transition, cell proliferation, cell differentiation, and structural-functional reconstruction were 88, 16, 79, 9, and 177, 90, 632, 207, respectively, illustrating that the associated genes triggered their expression mainly in the priming stage, and worked in different phases. Their expression similarity was classified into five groups and their expression patterns were categorized into 38 types, and the overall times of up-regulation and down-regulation were 589 and 427. Based on expression profiles and expression patterns of cell migration-associated genes in LR, it was confirmed that cell migration-associated genes rise in mRNA levels.
STABILITY AND HOPF BIFURCATION OF A PREDATOR–PREY SYSTEM WITH TIME DELAY AND HOLLING TYPE-II FUNCTIONAL RESPONSE
Authors: WANG LINGSHU , XU RUI , FENG GUANGHUI
Published: June 2009

A predator–prey model with time delay and Holling type-II functional response is investigated. By choosing time delay as the bifurcation parameter and analyzing the associated characteristic equation of the linearized system, the local stability of the system is investigated and Hopf bifurcations are established. The formulae determining the direction of bifurcations and the stability of bifurcating periodic solutions are given by using the normal form theory and center manifold theorem. Numerical simulations are carried out to illustrate the theoretical results.
Accessibility commons
Authors: Kawanaka Shinya , Kobayashi Masatomo , Takagi Hironobu , Asakawa Chieko
Published: June 2009

Metadata plays a crucial role for creating a more accessible Web environment, spanning from simple alternative texts for images to various types of UI widgets used in dynamic content. Beyond the current accessibility improvement methods that rely on inlined metadata embedded by the developers, various active research projects are focusing on external metadata which is the key to improve even existing content without touching the original code, so Web accessibility can be more flexible and adaptive to various user needs. Accessibility Commons is a new proposal to build a standardized shared repository for externalized metadata. It was initially proposed by IBM and three universities last year, and then proved its applicability through the Social Accessibility project. Now is the time to move beyond single-system-implementation to a federated data infrastructure for a wide range of Web accessibility research activities and a more adaptive Web environment for people throughout the world. After introducing the basic ideas, research projects, and technical challenges, we will discuss future directions, the potential, and broader applications.
SIGWEB annual report
Authors: Munson Ethan V.
Published: June 2009

SIGWEB has had an active and successful year since my last report to you in 2008. Our conferences and membership are growing. Our finances are sound. We are developing new programs including a system of student travel awards. I'll be reporting on these changes at SIGWEB Town Meetings at the upcoming JCDL, Hypertext, and DocEng conferences.
Interview with David Brailsford
Authors: Atzenbeck Claus
Published: June 2009

David Brailsford is the John Dunford Emeritus Professor of Computer Science at the University of Nottingham, UK. In 1986 he co-founded the Computer Science department and he was appointed to the Dunford chair in 1990. He served as Head of Department from 1990 to 1998. Since 1982 his research interests have focused on digital documents and on document engineering. He was General Chair for the first of the biennial "EP" conferences, which was held in Nottingham in 1986. This conference series then transformed into the annual, ACM-sponsored, Document Engineering Symposium from 2001 onwards. He has been on the program committee for these conferences since 1986 and he served as Program Chair for DocEng2006.

In 1988 he founded the Wiley journal "Electronic Publishing" which he edited for 10 years. Arising from this journal John Wiley Ltd funded a long-running research project, at Nottingham, on the automated internal hyperlinking of journals in PDF format. This led to a further collaboration with Wendy Hall, at the University of Southampton, on the more general hyperlinking of journal articles in a variety of formats.

David has collaborated with Adobe Systems Inc. on digital document research for more than 20 years. His research group became the first UK beta test site for Adobe Acrobat in 1992 and, over the years, six of his graduate students have supplemented their research training by undertaking summer internships at Adobe. Most of the joint research has centered around structured document components in PDF but more recently interest has turned to the possibilities for rich media documents in Adobe's AIR.

Since 2003 his Document Engineering Research Group has also collaborated with HP Laboratories on research topics ranging from XSLT transformations through to Variable Data Printing and eBooks.
Open, closed, or clopen access?
Authors: Vardi Moshe Y.
Published: June 2009

A frequent question I hear about
Communications
, and about ACM publishing in general, involves its access model.
Sharing ideas, writing apps, and creating a professional web presence
Authors: Guzdial Mark , Linden Greg , Lau Tessa
Published: June 2009

Greg Linden reveals his new approach to reading research papers, Mark Guzdial discusses how to encourage students to write computer programs, and Tessa Lau shares her ideas about the importance of Web visibility.
Contemporary approaches to fault tolerance
Authors: Wright Alex
Published: June 2009

Thanks to computer scientists like Barbara Liskov, researchers are making major progress with cost-efficient fault tolerance for Web-based systems.
Are we losing our ability to think critically?
Authors: Greengard Samuel
Published: June 2009

Computer technology has enhanced lives in countless ways, but some experts believe it might be affecting people's ability to think deeply.
Liskov's creative joy
Authors: Frenkel Karen A.
Published: June 2009

Barbara Liskov muses about the creative process of problem solving, finding the perfect design point, and pursuing a research path.
Master of connections
Authors: Joch Alan
Published: June 2009

Jon Kleinberg is honored for his pioneering research on the Web and social networking.
Technology strategy and managementGlobalization of knowledge-intensive professional services
Authors: Sako Mari
Published: June 2009

Does the trend toward standardization and modularization of professional services make outsourcing inevitable?
The business of softwareThe cliché defense
Authors: Armour Phillip G.
Published: June 2009

A guide to playing the ploys frequently employed by cliché-driven management.
The metropolis model a new logic for development of crowdsourced systems
Authors: Kazman Rick , Chen Hong-Mei
Published: June 2009

It takes a city of developers to build a big system that is never done.
Steps toward self-aware networks
Authors: Gelenbe Erol
Published: June 2009

Network software adapts to user needs and load variations and failures to provide reliable communications in largely unknown networks.
Q&ALiskov on Liskov
Authors: Hoffmann Leah
Published: June 2009

Barbara Liskov talks about her ground breaking work in data abstraction and distributed computing.
Churchman's inquirers as design templates for knowledge management systems
Authors: Parrish James L. , Courtney James F.
Published: June 2009

Introduction
A number of years ago, Peter Keen implored information systems researchers to develop theory they could call their own, which would build a cumulative tradition in the area, while maintaining close ties to practice; as it is central to the field, not peripheral. Even before that, Herbert Simon called for the development of a rigorous science of design that would also be relevant to the practice of computer science, information systems, business and engineering.

Relating to design, C. West Churchman's work on the design of inquiring systems1 has had a profound influence on research in management information systems over the years. Mason and Mitroff8 introduced this work into the MIS literature early on effectively making it endogenous to the field. Working both together and independently they went on to publish a host of articles based on inquiring systems and other books and papers by Churchman. They have inspired other IS researchers to follow in their footsteps. Ulrich has a website dedicated to Churchman and his work (http://www.geocities.com/csh_home/cwc_appreciation.html). His inquiring systems have been used as the basis for learning organizations, for knowledge management systems11 and proposed as kernel theories for knowledge management systems in general.

Despite all the work following on Churchman's original inquiring systems, Mason and Mitroff wrote recently: "To say that Singerian and Churchmanian systems are underrepresented is putting it kindly. They are virtually nonexistent." We believe that there are several reasons for this. First, the book is out of print and inaccessible. In addition, it is admittedly a difficult read, especially the passages on the Singerian inquirer. Even in lieu of the work that has been done on inquiring systems, perhaps many IS researchers believe the concepts are passé. After all, it's over 35 years old now! On the contrary, we believe that continued development of inquiring systems theory can provide continuity in IS research, serve as a theory that IS researchers can call their own, and contribute to the practice of information systems design.

The objective of this article is, first and foremost, to gain additional recognition for inquiring systems theories themselves, and to suggest ways in which they can provide the basis for contemporary design research. Essentially we argue that the inquirers can serve as logical design templates for various forms of information systems. We use an object oriented approach to describe the inquirers themselves, and then indicate how the inquirers can be viewed as logical design templates for instantiations or physical designs.
Unbalanced expanders and randomness extractors from Parvaresh--Vardy codes
Authors: Guruswami Venkatesan , Umans Christopher , Vadhan Salil
Published: June 2009

We give an improved explicit construction of highly unbalanced bipartite expander graphs with expansion arbitrarily close to the degree (which is polylogarithmic in the number of vertices). Both the degree and the number of right-hand vertices are polynomially close to optimal, whereas the previous constructions of Ta-Shma et al. [2007] required at least one of these to be quasipolynomial in the optimal. Our expanders have a short and self-contained description and analysis, based on the ideas underlying the recent list-decodable error-correcting codes of Parvaresh and Vardy [2005].

Our expanders can be interpreted as near-optimal “randomness condensers,” that reduce the task of extracting randomness from sources of arbitrary min-entropy rate to extracting randomness from sources of min-entropy rate arbitrarily close to 1, which is a much easier task. Using this connection, we obtain a new, self-contained construction of randomness extractors that is optimal up to constant factors, while being much simpler than the previous construction of Lu et al. [2003] and improving upon it when the error parameter is small (e.g., 1/poly(n)).
Quantifying inefficiency in cost-sharing mechanisms
Authors: Roughgarden Tim , Sundararajan Mukund
Published: June 2009

In a cost-sharing problem, several participants with unknown preferences vie to receive some good or service, and each possible outcome has a known cost. A cost-sharing mechanism is a protocol that decides which participants are allocated a good and at what prices. Three desirable properties of a cost-sharing mechanism are: incentive-compatibility, meaning that participants are motivated to bid their true private value for receiving the good; budget-balance, meaning that the mechanism recovers its incurred cost with the prices charged; and economic efficiency, meaning that the cost incurred and the value to the participants are traded off in an optimal way. These three goals have been known to be mutually incompatible for thirty years. Nearly all the work on cost-sharing mechanism design by the economics and computer science communities has focused on achieving two of these goals while completely ignoring the third.

We introduce novel measures for quantifying efficiency loss in cost-sharing mechanisms and prove simultaneous approximate budget-balance and approximate efficiency guarantees for mechanisms for a wide range of cost-sharing problems, including all submodular and Steiner tree problems. Our key technical tool is an exact characterization of worst-case efficiency loss in Moulin mechanisms, the dominant paradigm in cost-sharing mechanism design.
The complexity of obstruction-free implementations
Authors: Attiya Hagit , Guerraoui Rachid , Hendler Danny , Kuznetsov Petr
Published: June 2009

Obstruction-free
implementations of concurrent objects are optimized for the common case where there is no
step contention
, and were recently advocated as a solution to the costs associated with synchronization without locks. In this article, we study this claim and this goes through precisely defining the notions of obstruction-freedom and step contention. We consider several classes of obstruction-free implementations, present corresponding generic object implementations, and prove lower bounds on their complexity. Viewed collectively, our results establish that the worst-case operation time complexity of obstruction-free implementations is high, even in the absence of step contention. We also show that lock-based implementations are not subject to some of the time-complexity lower bounds we present.
A framework for efficient data anonymization under privacy and accuracy constraints
Authors: Ghinita Gabriel , Karras Panagiotis , Kalnis Panos , Mamoulis Nikos
Published: June 2009

Recent research studied the problem of publishing microdata without revealing sensitive information, leading to the privacy-preserving paradigms of
k
-anonymity and
l
-diversity.
k
-anonymity protects against the identification of an individual's record.
l
-diversity, in addition, safeguards against the association of an individual with specific sensitive information. However, existing approaches suffer from at least one of the following drawbacks: (i)
l
-diversification is solved by techniques developed for the simpler
k
-anonymization problem, causing unnecessary information loss. (ii) The anonymization process is inefficient in terms of computational and I/O cost. (iii) Previous research focused exclusively on the privacy-constrained problem and ignored the equally important accuracy-constrained (or dual) anonymization problem.

In this article, we propose a framework for efficient anonymization of microdata that addresses these deficiencies. First, we focus on one-dimensional (i.e., single-attribute) quasi-identifiers, and study the properties of optimal solutions under the
k
-anonymity and
l
-diversity models for the privacy-constrained (i.e., direct) and the accuracy-constrained (i.e., dual) anonymization problems. Guided by these properties, we develop efficient heuristics to solve the one-dimensional problems in linear time. Finally, we generalize our solutions to multidimensional quasi-identifiers using space-mapping techniques. Extensive experimental evaluation shows that our techniques clearly outperform the existing approaches in terms of execution time and information loss.
ODE
Authors: Su Weifeng , Wang Jiying , Lochovsky Frederick H.
Published: June 2009

Online databases respond to a user query with result records encoded in HTML files. Data extraction, which is important for many applications, extracts the records from the HTML files automatically. We present a novel data extraction method, ODE (Ontology-assisted Data Extraction), which automatically extracts the query result records from the HTML pages. ODE first constructs an ontology for a domain according to information matching between the query interfaces and query result pages from different Web sites within the same domain. Then, the constructed domain ontology is used during data extraction to identify the query result section in a query result page and to align and label the data values in the extracted records. The ontology-assisted data extraction method is fully automatic and overcomes many of the deficiencies of current automatic data extraction methods. Experimental results show that ODE is extremely accurate for identifying the query result section in an HTML page, segmenting the query result section into query result records, and aligning and labeling the data values in the query result records.
Certificate translation for optimizing compilers
Authors: Barthe Gilles , Grégoire Benjamin , Kunz César , Rezk Tamara
Published: June 2009

Proof Carrying Code provides trust in mobile code by requiring certificates that ensure the code adherence to specific conditions. The prominent approach to generate certificates for compiled code is Certifying Compilation, that automatically generates certificates for simple safety properties.

In this work, we present Certificate Translation, a novel extension for standard compilers that automatically transforms formal proofs for more expressive and complex properties of the source program to certificates for the compiled code.

The article outlines the principles of certificate translation, instantiated for a nonoptimizing compiler and for standard compiler optimizations in the context of an intermediate RTL Language.
The big bang
Authors: Hjorth Larissa
Published: June 2009

Over the last couple of years we have become used to the global media informing us about the revolutionary and democratic possibilities of mobile media. As a symbol of technological convergence, the multimedia possibilities of mobile media have become integral to the rise of UCC (user-created content) on the web. From the mobile novels (
keitai shosetsu
) in Japan, the OhMyNews netizens of South Korea, and the political use of mobile phones in the Philippines [Raphael 2003], the democratic and creative potential of mobile media have been exemplified in the Asia-Pacific region.

In a way, the rise of mobile media parallels the rise of the webcam [Koskela 2004] by enabling everyday users to document and edit their stories -- but mobile media promises more: a portal to new forms of distribution such as MySpace, Facebook, Cyworld mini-hompy, mixi, 2ch (
ni-channeru
), YouTube, and so on. Much of the innovative mobile media art work has been conducted around hybrid reality and location-based mobile gaming [De Souza and Silva 2006a; 2006; 2004; Davis 2005] to challenge the role of copresence in everyday life -- forging questions around boundaries between the virtual and actual, online and offline, haptic and cerebral, delay, and immediacy. Examples include the
PacManhattan
(US), Proboscis'
Urban Tapestries
(UK),
Blast Theory
(UK),
Aware
(FIN),
Mogi Game
(JP), and INP
Urban Vibe
(SK). In these projects we can see the melding of various traditions and disciplines, often exceeding the boundaries of games studies and new media discourse, apart from exceptions like the ‘relational architecture’ of new media artist, Rafael Lazano Hemmer.

Because mobile media grew in an interdisciplinary context, we must ask what role it can play in bringing new challenges to new media practice and theory. How can mobile media proffer insight into new media practice? How can mobile media's history as both a socio-cultural artefact and form of communication provide perception into emerging forms of new media politics in an age of global media? In order to address the potential of mobile media as new media, I will begin by discussing some aspects of what it means to be “mobile” in a period of globalization. I will then discuss South Korea as one of the major global leaders in mobile technologies, contextualising the socio-cultural dimensions of its techno-nationalist policy. I will then turn to the South Korean “mobile hacker” project, called Dotplay, conducted by INP. I argue that through this type of hactivist project we can begin to reflect the art of being immobile and mobile in an age of global UCC “flows”.
Joyce Hinterding and David Haines
Authors: Murphie Andrew
Published: June 2009

Since 1999, David Haines and Joyce Hinterding have created collaborative installations at the leading edge of art and technology. They work with precise and unapologetically beautiful combinations of subtle audio (often 5.1) and lush video (both recorded and animated). The installations sometimes include the like of kilometers of coiled copper wire, antennae or home-built electronics. Forces of technology and nature come together as an invitation to an expanded ecological engagement, with urban architecture at the edge of dissolution into floods, rolling clouds of smoke or the stratosphere. Their work explores unexpected resonance, one motivated by the “sympathetic amplification of the unseen” (Hinterding commenting on her work, Aeriology [1995]), and an unusual treatment of the images and sounds: inventive forms of high resolution, temporal distortion, and, sometimes, transduction (for example of audio signal into video signal, or vice versa). For Haines and Hinterding, this is not just a question of accuracy in representation, but a matter of bringing the unseen to attention.
Can local avatars satisfy a global audience? A case study of high-fidelity 3D facial avatar animation in subject identification and emotion perception by US and international groups
Authors: Yun Chang , Deng Zhigang , Hiscock Merrill
Published: June 2009

This study investigates effectiveness of a local high-fidelity 3D facial avatar for a global audience by observing how US and International student groups differed in identifying subjects and perceiving emotions while viewing nonverbal high-fidelity 3D facial avatar animations embedded with the motion data of three US individuals. To synthesize the animated 3D avatars to convey highly believable facial expressions, a 3D scanned facial model was mapped with high-fidelity motion-capture data of three native US subjects as they spoke designated English sentences with specified emotions. Simple animations in conjunction with actual footage of the subjects speaking during the facial motion-capture sessions were shown several times to both native US and international students in similar settings. After a familiarization process, we showed the students randomly arranged talking avatars without voices and asked them to identify the corresponding identities and emotional types of the subjects whose facial expressions were utilized in the creation of the avatars, and to rate their confidence in their selections. We found that the US group had higher success rates in subject identification, although the related difference in confidence ratings between two groups was not significant. The differences in the success rates and confidence ratings on the perception of emotion between the two groups were not significant either. The results of our study provide interesting insights into avatar-based interaction where the national and/or cultural background of a person impacts the perception of identity while having little effect on the perception of emotion. However, we observed that dynamics (e.g., head motion) could offset the disadvantage of cultural unfamiliarity in subject identification. We observed that both groups performed at a nearly identical level in subject identification and emotion perception when they were shown the avatar animation with heightened expression and dynamic intensities. In addition, we observed that the confidence ratings were correlated to accuracy in identifying the subject but not to accuracy in perceiving emotion.
Online action adaptation in interactive computer games
Authors: Hartley Thomas , Mehdi Quasim
Published: June 2009

Nonplayer characters (NPCs) in today's computer games lack the ability to adapt to situations that were not envisaged by the artificial intelligence (AI) programmer. This lack of adaptation produces lifeless characters that are prone to repetitive and predictable behavior. In this article, we present our work towards the development of an online learning and adaptation architecture for NPCs in first-person shooter (FPS) computer games. Our architecture builds upon incremental case-based approaches to modelling an observed entity, and makes a number of novel contributions. In particular, we develop a dual state representation to enhance case matching, and use adaptive k-d tree-based techniques to improve case storage and retrieval. The dual state representation allows more game features to be represented in the system, which enables observed behavior to be more accurately recorded and actions predicted. The system is applied to the Unreal Tournament using the GameBots API and evaluated in a number of different game scenarios. Our results show that the adaptation system can accurately predict a human player's actions and that our dual state representation enhances prediction. We also demonstrate that an adaptive k-d tree-based technique can be used online to maintain a balanced tree of observed cases.
Automatic prototyping in model-driven game development
Authors: Reyno Emanuel Montero , Carsí Cubel José Á
Published: June 2009

Model-driven game development (MDGD) is an emerging paradigm where models become first-order elements in game development, maintenance, and evolution. In this article, we present a first approach to 2D platform game prototyping automatization through the use of model-driven engineering (MDE). Platform-independent models (PIM) define the structure and the behavior of the games and a platform-specific model (PSM) describes the game control mapping. Automatic MOFscript transformations from these models generate the software prototype code in C++. As an example, Bubble Bobble has been prototyped in a few hours following the MDGD approach. The resulting code generation represents 93% of the game prototype.
Derivability, redundancy and consistency of relations stored in large data banks
Authors: E, F. Codd E. F.
Published: June 2009

The large, integrated data banks of the future will contain many relations of various degrees in stored form. It will not be unusual for this set of stored relations to be redundant. Two types of redundancy are defined and discussed. One type may be employed to improve accessibility of certain kinds of information which happen to be in great demand. When either type of redundancy exists, those responsible for control of the data bank should know about it and have some means of detecting any "logical" inconsistencies in the total set of stored relations. Consistency checking might be helpful in tracking down unauthorized (and possibly fraudulent) changes in the data bank contents.
An X-ray on web-available XML schemas
Authors: Laender Alberto H.F. , Moro Mirella M. , Nascimento Cristiano , Martins Patrícia
Published: June 2009

XML has conquered its place as the most used standard for representing Web data. An XML schema may be employed for similar purposes of those from database schemas. There are different languages to write an XML schema, such as DTD and XSD. In this paper, we provide a general view, an X-Ray, on Web-available XSD files by identifying which XSD constructs are more and less frequently used. Furthermore, we provide an evolution perspective, showing results from XSD files collected in 2005 and 2008. Hence, we can also draw some conclusions on what trends seem to exist in XSD usage. The results of such study provide relevant information for developers of XML applications, tools and algorithms in which the schema has a distinguished role.
Rethinking cost and performance of database systems
Authors: Florescu Daniela , Kossmann Donald
Published: June 2009

Traditionally, database systems were optimized in the following way: "Given a set of machines, try to minimize the response time of each request." This paper argues that today, users would like a database system to optimize the opposite question: "Given a response time goal for each request, try to minimize the number of machines (i.e., cost in $)." Furthermore, this paper gives an example that demonstrates that the new optimization problem may result in a totally different system architecture.
GOSR
Authors: Zhongyi Liu , Tong Zhao , Wei Yan , Xiaoming Li
Published: June 2009

Geographical source routing is a promising routing technique for VANETs, due to its adaptability for network dynamics and ability to handle topology holes. In traditional geographical source routing algorithms a best-known neighbor, typically the neighbor nearest to the next junction in a greedy fashion, is designated as the next hop. This approach may cause two drawbacks: (1) the designated neighbor might not receive the packet correctly and (2) non-neighbor nodes are never given opportunities to do forwarding. Due to the broadcast nature of wireless media, non-neighbor nodes can overhear the transmission and may offer better forwarding progress than the designated neighbor. In this paper, we resolve the above two problems by introducing the concept of opportunistic routing to geographical source routing. A new routing protocol, named Geographical Opportunistic Source Routing (GOSR), is developed. GOSR allows non-neighbor nodes as well as the best-known neighbor to become a forwarder. The notification cost of opportunistic routing is minimized by enforcing a scope from which candidate forwarders are selected. Defer timers are adopted to avoid conflicts caused by simultaneous transmissions by nodes in the designated scope. Simulation results show that GOSR can substantially reduce hop count and also improve end-to-end delivery ratio remarkably.
Trace-based analysis of Wi-Fi scanning strategies
Authors: Falaki Hossein , Keshav Srinivasan
Published: June 2009

The number of smartphones in use is overwhelmingly increasing every year. These devices rely on connectivity to the Internet for the majority of their applications. The everincreasing number of deployed 802.11 wireless access points and the relatively high cost of other data services make the case for opportunistic communication using free WiFi hotspots. However, this requires effective management of the WLAN interface, because by design the energy cost of WLAN scanning and interface idle operation is high and energy is a primary resource on mobile devices. We study several heuristic strategies for interface management, and use real-world user traces to evaluate and compare their performance against the optimal algorithm. Trace-based simulations show that simple static scanning with a suitable interval value is very effective for delay-tolerant, background applications.
Courier problems
Authors: Bhattacharyya Malay
Published: June 2009

Courier problems comprise a set of recently proposed combinatorial optimization problems, which are inspired by some novel requirements in railway wagon scheduling. In these problems, scheduling strategies of some mobile couriers are considered. These mobile couriers initially reside at some fixed location. They are assigned some duties of commodity transfer between different pairs of locations. The scenario may be static or dynamic. The motivation is to optimize the movement of the couriers over the constraint of the traversed path or the associated cost. We discuss here some varieties of the courier problems formalized on graphs and address the potential methods of their solution.
The Sudbury Neutrino Observatory
Authors: Jelley Nick , McDonald Arthur B. , Robertson R.G. Hamish
Published: June 2009

The solar neutrino problem arose when the first measurements of the flux of neutrinos from the Sun, taken by Raymond Davis, Jr. with a Cl-Ar radiochemical detector, fell substantially below the value predicted theoretically by John Bahcall. Bahcall's prediction came from a detailed model of the nuclear reactions powering the Sun. Resolution of the problem came three decades later with the observation of nonelectron flavors of neutrinos in the solar flux. The use of heavy water in the Sudbury Neutrino Observatory (SNO) experiment provided a means to measure both electron and nonelectron components, and the presence of the latter showed that neutrino flavor conversion was taking place—a hallmark of neutrino oscillation and mass. The solar models were vindicated, and the Standard Model of elementary particles and fields had to be revised. Here we present an account of the SNO project, its conclusions to date, and its ongoing analysis.
Biwave Maps into Manifolds
Authors: Chiang Yuan-Jen
Published: June 2009

We generalize wave maps to biwave maps. We prove that the composition of a biwave map and a totally geodesic map is a biwave map. We give examples of biwave nonwave maps. We show that if f is a biwave map into a Riemannian manifold under certain circumstance, then f is a wave map. We verify that if f is a stable biwave
map into a Riemannian manifold with positive constant sectional curvature satisfying the conservation law, then f is a wave map. We finally obtain a theorem involving an unstable biwave map.
Is Chronic Inflammation a Possible Cause of Obesity-Related Depression?
Authors: Olszanecka-Glinianowicz Magdalena , Zahorska-Markiewicz Barbara , Kocełak Piotr , Janowska Joanna , Semik-Grabarczyk Elżbieta , Wikarek Tomasz , Gruszka Wojciech , Dąbrowski Piotr
Published: June 2009

Adult obesity has been associated with depression, especially in women. Whether depression leads to obesity or obesity causes depression is unclear. Chronic inflammation is observed in obesity and depression. In 63 obese women without additional diseases depression level was assessed with the Beck's questionnaire. After evaluation of depression level study group was divided into groups according to the mood status (A—without depression, B—mild depression, and C—severe depression), and serum concentration of TNF-α, sTNFs, leptin, and IL-6 were measured by ELISA. No differences in age, body mass, BMI, and body composition were observed in study groups. We did not observe differences of serum concentrations of TNF-α, sTNFRs, leptin, and IL-6 between subgroup A and subgroups B and C. It seems that circulating adipokines did not exert influence on depression levels in obese women.
Intestinal Radiation-Induced Stricture Favours Small Bowel Obstruction by Phytobezoar: Report of a Case
Authors: Quercioli Alessandra , Dallegri Franco , Ottonello Luciano , Montecucco Fabrizio , Borgonovo Giacomo
Published: June 2009

Bezoars represent the fifth most frequent cause of acute small bowel obstruction. Phytobezoar is the most common type of bezoar. It is a concretion of undigestible fibers derived from ingested vegetables and fruits. We report a case of a woman with a 1-year history of recurrent epigastric and periumbilical abdominal pain with intermittent vomiting caused by phytobezoar of the terminal ileum. After careful investigation of the case and review of literature, we identified the factor involved in bezoar formation as radiation-induced ileal stenosis due to previous treatment for a pelvic tumour. This report provides evidence to consider phytobezoar as a possible cause of small bowel obstruction in patients previously treated with abdominal radiotherapy.
Sequence Characterization of the MC1R Gene in Yak (Poephagus grunniens) Breeds with Different Coat Colors
Authors: Chen Shi-Yi , Huang Yi , Zhu Qing , Fontanesi Luca , Yao Yong-Gang , Liu Yi-Ping
Published: June 2009

Melanocortin 1 receptor (MC1R) gene plays a key role in determining coat color in several species, including the cattle. However, up to now there is no report regarding the MC1R gene and the potential association of its mutations with coat colors in yak (Poephagus grunniens). In this study, we sequenced the encoding region of the MC1R gene in three yak breeds with completely white (Tianzhu breed) or black coat color (Jiulong and Maiwa breeds). The predicted coding region of the yak MC1R gene resulted of 954 bp, the same to that of the wild‐type cattle sequence, with >99% identity. None of the mutation events reported in cattle was found. Comparing the yak obtained sequences, five nucleotide substitutions were detected, which defined three haplotypes (EY1, EY2, and EY3). Of the five mutations, two, characterizing the EY1 haplotype, were nonsynonymous substitutions (c.340C>A and c.871G>A) causing amino acid changes located in the first extracellular loop (p.Q114K) and in the seventh transmembrane region (p.A291T). In silico prediction might indicate a functional effect of the latter substitution. However, all three haplotypes were present in the three yak breeds with relatively consistent frequency distribution, despite of their distinguished coat colors, which suggested that there was no across‐breed association between haplotypes or genotypes and black/white phenotypes, at least in the investigated breeds. Other genes may be involved in affecting coat color in the analyzed yaks.
Calcium-Independent Phospholipase A2β Is Dispensable in Inflammasome Activation and Its Inhibition by Bromoenol Lactone
Authors: Franchi Luigi , Chen Grace , Marina-Garcia Noemi , Abe Akira , Qu Yan , Bao Shunzhong , Shayman James A. , Turk John , Dubyak George R. , Núñez Gabriel
Published: June 2009

Calcium-independent phospholipase A2 (iPLA2) has been suggested to play an important role in the activation of caspase-1 induced by lipopolysaccharides (LPS). Here, we used pharmacological and genetic approaches to study the role of iPLA2 in the activation of caspase-1. Bromoenol lactone (BEL), an inhibitor that was originally used to support a role for iPLA2 in the secretion of IL-1β, prevented caspase-1 activation induced by LPS and ATP as described, and also activation triggered by Salmonella infection and cytosolic flagellin, which rely on the Nlrc4 inflammasome. Analysis of BEL enantiomers showed that the S-BEL form was more effective than R-BEL in inhibiting the inflammasome, suggesting a role for iPLA2β. However, caspase-1 activation and IL-1β secretion and their inhibition by BEL were unimpaired in macrophages deficient in iPLA2β. BEL was originally identified as an inhibitor of serine proteases. Consistent with the latter, the serine proteases inhibitors TPCK, TLCK and AAF-cmk prevented the activation of the Nlrc4 and Nlrp3 inflammasomes while pan-cathepsin inhibitors were ineffective. These results indicate that iPLA2β is not critical for caspase-1 activation as currently proposed. Instead, the results suggest that serine protease(s) targeted by BEL may play a critical role in the activation of the inflammasome triggered by microbial stimuli.
Comparison of Inflammatory Response After Implantation of Sirolimus- and Paclitaxel-Eluting Stents in Porcine Coronary Arteries
Authors: Wilson Gregory J. , Nakazawa Gaku , Schwartz Robert S. , Huibregtse Barbara , Poff Bradley , Herbst Thomas J. , Baim Donald S. , Virmani Renu
Published: June 2009

Background—

Although both sirolimus (CYPHER) and paclitaxel (TAXUS) drug-eluting stents have demonstrated efficacy and safety in clinical trials, human autopsy data have raised concerns about long-term healing and the potential for local inflammatory reactions.

Methods and Results—

Overlapping stents (CYPHER drug-eluting stents, Bx SONIC bare metal stents, TAXUS drug-eluting stents, and Liberté bare metal stents) were implanted in noninjured coronary arteries of 58 domestic swine. Histopathological evaluation of proximal, overlapped, and distal stented segments was determined with emphasis on inflammation at 30, 90, and 180 days. Circumferential granulomatous inflammation in all stented segments was defined as inflammation consisting of macrophages, multinucleated giant cells, lymphocytes, and granulocytes, including many eosinophils, adjacent to almost all struts. Circumferential granulomatous inflammation was more prevalent in CYPHER (9 of 23, 39%) compared with TAXUS (1 of 21, 5%;
P
=0.01) and control bare metal stents (0 of 44) in the combined 90- and 180-day cohorts. Only CYPHER specimens showed marked adventitial inflammation (
P
=0.0025) and fibrosis (
P
=0.0055) accompanied by extensive remodeling. Fibrin deposition within neointima and medial smooth muscle cell death were greater (both
P
<0.001) in TAXUS than CYPHER at 30 days, with more fibrin in TAXUS than CYPHER through 90 days (
P
<0.05).

Conclusions—

Although these data cannot be directly extrapolated to humans, the high prevalence in this porcine model of diffuse granulomatous inflammation seen with CYPHER stents, persisting at 180 days and associated with extensive remodeling of the artery, and persistent para-strut fibrin deposition with TAXUS stents emphasize the need for further investigation of biocompatibility with these and other novel combination drug/polymer drug-eluting stents.
Diabetes Mellitus Activates Signal Transduction Pathways Resulting in Vascular Endothelial Growth Factor Resistance of Human Monocytes
Authors: Tchaikovski Vadim , Olieslagers Servé , Böhmer Frank -D. , Waltenberger Johannes
Published: June 2009

Background—

Monocytes are cellular components of wound repair, arteriogenesis, and atherogenesis. Vascular endothelial growth factor (VEGF)-A and placental growth factor recruit monocytes to sites of arteriogenesis via stimulation of VEGF receptor-1 (VEGFR-1). The chemotactic response of monocytes to VEGF-A is attenuated in individuals with diabetes mellitus (DM). This VEGF resistance correlates with impaired collateral growth. The aim of this study is to elucidate the molecular basis of VEGF resistance and impaired monocyte response in DM.

Methods and Results—

Phosphorylation of Akt, p38, and extracellular signal-regulated kinase 1/2 (ERK1/2) could be stimulated with either placental growth factor-1 or VEGF-A in monocytes from non-DM but not DM individuals. In contrast, formyl-methionyl-leucyl-phenylalanine caused a comparable activation of these molecules in both DM and non-DM monocytes. Baseline phosphorylation of Akt, p38, and ERK1/2 was significantly elevated in monocytes from DM compared with non-DM subjects. Of note, H
2
O
2
activated Akt, p38, and ERK1/2 in non-DM monocytes ex vivo. Protein tyrosine phosphatases had stronger oxidative modifications in monocytes from DM than from non-DM individuals, which reflects functional protein tyrosine phosphatase inhibition, similar to that seen after H
2
O
2
challenge. Overall, protein tyrosine phosphatase and protein tyrosine phosphatase-1B activity were reduced in DM monocytes. DM monocytes revealed higher expression of the receptor for advanced glycation end products. Stimulation with advanced glycation end products ligands resulted in activation of non-DM monocytes and inhibition of VEGFR-1–mediated chemotaxis. The elevated baseline phosphorylation/activation of Akt, p38, and ERK1/2 in DM monocytes likely causes the resistance to further stimulation with specific stimuli such as VEGF-A, revealing a molecular explanation of the DM-related signal transduction defect.

Conclusions—

We propose that elevated advanced glycation end products expression and increased oxidative stress in diabetic monocytes lead to activation of VEGFR-1–related signaling pathways and to desensitization of VEGFR-1 responses. These data establish VEGF resistance as a novel molecular concept for DM-related cellular dysfunction.