bluuebunny/crossref_metadata_2025 huggingface dataset:
Growth codes
Authors: Kamra Abhinav , Misra Vishal , Feldman Jon , Rubenstein Dan
Published: October 2006

Sensor networks are especially useful in catastrophic or emergency scenarios such as floods, fires, terrorist attacks or earthquakes where human participation may be too dangerous. However, such disaster scenarios pose an interesting design challenge since the sensor nodes used to collect and communicate data may themselves fail suddenly and unpredictably, resulting in the loss of valuable data. Furthermore, because these networks are often expected to be deployed in response to a disaster, or because of sudden configuration changes due to failure, these networks are often expected to operate in a "zero-configuration" paradigm, where data collection and transmission must be initiated immediately, before the nodes have a chance to assess the current network topology. In this paper, we design and analyze techniques to increase "persistence" of sensed data, so that data is more likely to reach a data sink, even as network nodes fail. This is done by replicating data compactly at neighboring nodes using novel "Growth Codes" that increase in efficiency as data accumulates at the sink. We show that Growth Codes preserve more data in the presence of node failures than previously proposed erasure resilient techniques.
ROFL
Authors: Caesar Matthew , Condie Tyson , Kannan Jayanthkumar , Lakshminarayanan Karthik , Stoica Ion , Shenker Scott
Published: October 2006

It is accepted wisdom that the current Internet architecture conflates network locations and host identities, but there is no agreement on how a future architecture should distinguish the two. One could sidestep this quandary by routing directly on host identities themselves, and eliminating the need for network-layer protocols to include any mention of network location. The key to achieving this is the ability to route on flat labels. In this paper we take an initial stab at this challenge, proposing and analyzing our ROFL routing algorithm. While its scaling and efficiency properties are far from ideal, our results suggest that the idea of routing on flat labels cannot be immediately dismissed.
Quantifying Skype user satisfaction
Authors: Chen Kuan-Ta , Huang Chun-Ying , Huang Polly , Lei Chin-Laung
Published: October 2006

The success of Skype has inspired a generation of peer-to-peer-based solutions for satisfactory real-time multimedia services over the Internet. However, fundamental questions, such as whether VoIP services like Skype are good enough in terms of user satisfaction,have not been formally addressed. One of the major challenges lies in the lack ofan easily accessible and objective index to quantify the degree of user satisfaction.In this work, we propose a model, geared to Skype, but generalizable to other VoIP services, to quantify VoIP user satisfaction based on a rigorous analysis of the call duration from actual Skype traces. The User Satisfaction Index (USI) derived from the model is unique in that 1) it is composed by objective source-and network-level metrics, such as the bit rate, bit rate jitter, and round-trip time, 2) unlike speech quality measures based on voice signals, such as the PESQ model standardized by ITU-T, the metrics are easily accessible and computable for real-time adaptation, and 3) the model development only requires network measurements, i.e., no user surveys or voice signals are necessary. Our model is validated by an independent set of metrics that quantifies the degree of user interaction from the actual traces.
Drafting behind Akamai (travelocity-based detouring)
Authors: Su Ao-Jan , Choffnes David R. , Kuzmanovic Aleksandar , Bustamante Fabián E.
Published: October 2006

To enhance web browsing experiences, content distribution networks (CDNs) move web content "closer" to clients by caching copies of web objects on thousands of servers worldwide. Additionally, to minimize client download times, such systems perform extensive network and server measurements, and use them to redirect clients to different servers over short time scales. In this paper, we explore techniques for inferring and exploiting network measurements performed by the largest CDN, Akamai; our objective is to locate and utilize quality Internet paths
without
performing extensive path probing or monitoring.Our contributions are threefold. First, we conduct a broad measurement study of Akamai's CDN. We probe Akamai's network from 140 PlanetLab vantage points for two months. We find that Akamai redirection times, while slightly higher than advertised, are sufficiently low to be useful for network control. Second, we empirically show that Akamai redirections overwhelmingly correlate with
network
latencies on the paths between clients and the Akamai servers. Finally, we illustrate how large-scale overlay networks can exploit Akamai redirections to identify the best detouring nodes for one-hop source routing. Our research shows that in more than 50% of investigated scenarios, it is better to route through the nodes "recommended" by Akamai, than to use the direct paths. Because this is not the case for the rest of the scenarios, we develop lowoverhead pruning algorithms that avoid Akamai-driven paths when they are not beneficial.
Learning to program through the web
Authors: Truong Nghi , Bancroft Peter , Roe Paul
Published: October 2006

Computer-based tutoring systems which assist students in solving introductory programming problems have significant potential for improving the quality of programming education and reducing the instructor's work load. The innovative Environment for Learning to Program (ELP) provides an interactive web-based environment for teaching programming to first year Information Technology students at Queensland University of Technology (QUT). ELP allows students to undertake programming exercises by "filling in the gaps" of a partial computer program presented in a web page and to receive guidance in getting their programs to compile and run. Feedback on quality and correctness is provided through a program analysis framework. Students are given the opportunity to produce working programs at the early stages of their course without the need to familiarize themselves with a complex program development environment.
A research-led curriculum in multimedia
Authors: Davis Hugh C. , White Su
Published: October 2006

Traditional teaching methods have acknowledged limitations. Lectures may be used to transmit information efficiently, but often fail to motivate students to engage with the subject. Coursework assessments and examinations may lack authenticity and thus fail to help students develop 'real world' skills even though they ensure technical competence.This paper presents a teaching innovation motivated from a social constructivist perspective whereby undergraduates researched, reviewed, and presented their papers at a one day conference, by way of preparing for a written examination.The paper presents theory supporting this change, our experiences from running the course, and improvements in learning we observed. We identify the value of undergraduate conferences beyond serving as a vehicle for communication skills. We identify an approach which engages learners and realizes higher level learning objectives by using authentic activities. The process has identified a 'research-led' approach which clarifies the similarity between research processes and effective independent learning strategies and is valued by students, faculty and stakeholders alike.
Exploring students' understanding of the concept of algorithm
Authors: Perrenet Jacob , Groote Jan Friso , Kaasenbrood Eric
Published: October 2006

How do we know if our students are beginning to think like computer scientists? In this study we have defined four levels of abstraction in the thinking of computer science students about the concept of algorithm. We constructed a list of questions about algorithms to measure the answering level as an indication for the thinking level. This list was presented to various groups of Bachelor Computer Science students. The mean answering level increased between successive year groups as well as within year groups during the year, mainly from the second to the third level. Little relation was found between answering levels and test results on algorithm oriented courses. The study was inspired by the tradition of mathematics education research.
Implications of perspective in teaching objects first and object design
Authors: Christensen Henrik Baerbak
Published: October 2006

There are an increasing number of books published on the important topics of "object-oriented programming" and "object-oriented design" for use in education. However, object-orientation can be viewed from a number of different perspectives---each perspective having its benefits and liabilities. A perspective has a strong influence on the kind of designs students can and will produce, the kind of domains that are easy or difficult to analyze, and the kind of frame of reference in which design techniques are understood and applied. In this paper we argue that most books make an implicit choice of perspective with the unfortunate effect that our students leave our courses with limited design abilities. We present a coarse-grained classification, discuss implications of perspective in a teaching context, and illustrate consequences using a small case study. Our main point is that teachers should be aware of the different perspectives, and that all perspectives are important for students to achieve high quality designs.
Teaching transaction management with SQL examples
Authors: Fekete Alan
Published: October 2006

Transaction management is an important topic in the database course. This remains true whether the subject has an application focus or a systems internals focus. All the standard textbooks use "toy" examples of transactions, expressed as sequences of simple operations such as reading or writing data items. In this paper we argue that the teacher should choose examples which are closer to the students' experiences in other topics of the course, that is, the transactions should be like programs with SQL statements. We discuss the requirements that must be considered in choosing useful examples, and we give a set of examples that we have constructed to meet many of these requirements.
Analyzing relationships between closed labs and course activities in CS1
Authors: Soh Leen-Kiat , Samal Ashok , Person Suzette , Nugent Gwen , Lang Jeff
Published: October 2006

Closed laboratories are becoming an increasingly popular approach to teaching introductory computer science courses. However, as observed in [1], "Considering the prevalence of closed labs and the fact that they have been in place in CS curricula for more than a decade, there is little published evidence assessing their effectiveness." In this paper, we report on how students' performance in closed laboratories relates to their performances on a placement exam, homework assignments, course exams, and how it relates to their self-reported attitudes towards our CS1 course. This analysis provides insights to help us improve the design of our laboratories as well as other components of CS1.
A constructivist framework for operating systems education
Authors: Maia Luiz Paulo , Machado Francis Berenger , Pacheco Ageu C.
Published: October 2006

A conventional teaching approach, when applied specifically to the discipline of Operating Systems (OS), seems to fall short of attaining the overall objective, sometimes leaving the lecturer unsure about the students' actual understanding of the dynamic nature of OS concepts and mechanisms. This paper presents a pedagogical proposal, based on constructivist ideas, as a means of making the process of learning OS more efficient and interesting. The framework presented here uses the SOsim graphical simulator as a support tool, creating a teaching and learning environment in which practical experiments can be undertaken as each OS topic is introduced and explained.
"Computer science, academia, and industry" educational project
Authors: Yehezkel Cecile , Haberman Bruria
Published: October 2006

A special program in Software Engineering (SE) for high school has been in operation in Israel whose aim is to expose young students to the field of computing. During their studies the students are required to develop a software project, and thus gain experience in software design. Usually the development processes do not fulfill essential professional requirements, and the students' products are rarely applicable to real world situations. This motivated the initiation of an educational program designated for advanced students. In the first stage of the program, a regional out-of-school class attends an enrichment workshop. In the second stage students develop projects under the apprenticeship-based supervision of professional instructors from academia and industry. The project is currently being implemented for the first time and is being evaluated.
What attracts women to CS?
Authors: Almstrum Vicki L. , Last Mary Z.
Published: October 2006

This poster presents the findings of a study that used grounded theory methodology to analyze hypothesized reasons for why women choose computing as a profession. Preliminary analysis has resulted in four categories of attraction factors that validate research results from other gender studies.
Using a PC simulator to illustrate input-output programming techniques
Authors: Medeiros Pedro D. , Duarte Vitor A. , Gomes M. Cecilia , Marques Rui F.
Published: October 2006

We present our use of the Bochs PC emulator in a series of pratical assignments that, in a basic computer architecture course, introduce polling and interrupt-based input-output programming techniques.
Learning UNIX in first year of computer engineering
Authors: Simón-Hurtado Ma Aránzazu , Vivaracho-Pascual Carlos
Published: October 2006

We describe an experience of cooperative learning for teaching the UNIX operating system in first year of Computer Engineering that helps the students to work with constancy, motivates them to attend the laboratory sessions, stay with the subject, and promotes social and communication skills. This methodology has been very satisfactorily valued by the students.
Understanding disciplinary differences
Authors: Liccardi Ilaria , White Su
Published: October 2006

This poster presents research into ways in which electronic based methods can be used in teaching. Specifically it wishes to examine how appropriate techniques and technologies may be selected, tailored and combined for effectiveness, based on disciplinary differences.The research reviews existing literature, surveys existing practices and research into new techniques which may be adopted for electronic learning. It also analyses quantitative and qualitative data gathered from interviews with students across a number of academic disciplines.
Constructing database applications for PDA using the .NET framework
Authors: Guimaraes Mario
Published: October 2006

This tutorial will give participants the necessary knowledge to create applications using the .NET framework as well as create applications for a PDA. We will give an overview of different technologies available for creating PDA applications, but we will focus primarily on Visual Basic .NET, Appforge's Crossfire, Sybase's Ultralite, and the Pocket PC. Links to popular Database (http://coffee.kennsaw.ed , etc.) sites as well as popular sites for constructing .NET and PDA applications will be presented (briefly). We will also talk about how we currently teach a graduate course with mobile databases as well as database courseware developed at our institution. This is a hands-on workshop - pocket pc or pocket pc simulator will be available for use by workshop attendees.
Ten years on internet time
Authors: Treese Win
Published: October 2006

When did you start using the Internet? Ten years ago, in 1996, there were about 40 million people in the US and Canada with online access. The number worldwide was less than twice that. Today, over one billion people are estimated to be on the Internet.
In our trusty cage
Authors: Weiss Aaron
Published: October 2006

Admittedly, the term "Trusted Computing" isn't as conspiratorial as it sounds. Within computer security circles, to "trust" a system has a long and legitimate history describing available degrees of credentials. Indeed, the Trusted Computing Group, a Who's Who list of major technology vendors from Microsoft to Intel to IBM, consciously emphasizes the security pedigree implied by their name. But don't let the name fool you. Ultimately, it isn't the machines the TCG aims to make trustworthy. It's their customers.
The cyclic multi-peg Tower of Hanoi
Authors: Berend Daniel , Sapir Amir
Published: October 2006

Variants of the classical Tower of Hanoi problem evolved in various directions. Allowing more than 3 pegs, and imposing limitations on the possible moves among the pegs, are two of these. Here, we deal with the case of
h
≥3 pegs arranged on a circle, where moves are allowed only from a peg to the next peg (in the clockwise direction). Unlike the multi-peg problem without restrictions on moves between pegs, the complexity of this variant as a function of the number of disks is exponential. We find explicit lower and upper bounds for its complexity for any
h
, and show how this complexity can be estimated arbitrarily well for any specific
h
.
An EDF schedulability test for periodic tasks on reconfigurable hardware devices
Authors: Danne Klaus , Platzner Marco
Published: October 2006

In this paper, we consider the scheduling of periodic real-time tasks on reconfigurable hardware devices. Such devices can execute several tasks in parallel. All executing tasks share the hardware resource, which makes the scheduling problem differ from single- and multiprocessor scheduling. We adapt the global EDF multiprocessor scheduling approach to the reconfigurable hardware execution model and define two preemptive scheduling algorithms,
EDF-First-k-Fit
and
EDF-Next-Fit
. For these algorithms, we present a novel linear-time schedulability test and give a proof based on a resource augmentation technique. Then, we propose a task placement and relocation scheme utilizing partial device reconfiguration. This scheme allows us to extend the schedulability test to include reconfiguration time overheads. Experiments with synthetic workloads compare the scheduling test with the actual scheduling performance of
EDF-First-k-Fit
and
EDF-Next-Fit
. The main evaluation result is that the reconfiguration overhead is acceptable if the task computation times are one order of magnitude higher than the device reconfiguration time.
Facing the Strain
Authors: Neville-Neil George
Published: October 2006

Dear KV, I’ve been working on a software team that produces an end-user application on several different operating system platforms. I started out as the build engineer, setting up the build system, then the nightly test scripts, and now I work on several of the components themselves, as well as maintaining the build system. The biggest problem Ive seen in building software is the lack of API stability. It’s OK when new APIs are added--you can ignore those if you like--and when APIs are removed I know, because the build breaks. The biggest problem is when someone changes an API, as this isn’t discovered until some test script--or worse, a user--executes the code and it blows up. How do you deal with constantly changing APIs?
A Requirements Primer
Authors: Beeler George W. , Gardner Dana
Published: October 2006

Many software engineers and architects are exposed to compliance through the growing number of rules, regulations, and standards with which their employers must comply. Some of these requirements, such as HIPAA, focus primarily on one industry, whereas others, such as SOX, span many industries. Some apply to only one country, while others cross national boundaries.
Box Their SOXes Off
Authors: Bostick John
Published: October 2006

Data is a precious resource for any large organization. The larger the organization, the more likely it will rely to some degree on third-party vendors and partners to help it manage and monitor its mission-critical data. In the wake of new regulations for public companies, such as Section 404 of SOX, the folks who run IT departments for Fortune 1000 companies have an ever-increasing need to know that when it comes to the 24/7/365 monitoring of their critical data transactions, they have business partners with well-planned and well-documented procedures. In response to a growing need to validate third-party controls and procedures, some companies are insisting that certain vendors undergo SAS 70 Type II audits. These audits refer to an AICPA standard that sets forth the practice for evaluating the performance of outside service organizations.
Perceptual antecedents of user attitude in electronic commerce
Authors: Gao Yuan , Koufaris Marios
Published: October 2006

This paper examines three cognitive antecedents of Web user attitude toward a commercial website -- perceived informativeness, perceived entertainment, and perceived irritation. We tested the theoretical relationships between the three cognitive antecedents, attitude toward the site, and intention to return to the site using Partial Least Squares (PLS) with data collected in a field study of three e-commerce websites. The model explains a high percentage of the variance in attitude toward the site and intention to return and all the coefficients in the model are significant. We conclude that both perceived informativeness and perceived entertain-ment are significantly and positively related to attitude toward the site, while perceived irritation is significantly and negatively related to attitude toward the site. We also conclude that attitude toward the site is significantly and positively related to a user's intention to return to the site.
Backing up in singly linked lists
Authors: Ben-Amram Amir M. , Petersen Holger
Published: October 2006

We show how to reduce the time overhead for implementing two-way movement on a singly linked list to
O
(
n
ϵ
) per operation without modifying the list and without making use of storage other than a finite number of pointers into the list. We also prove a matching lower bound.These results add precision to the intuitive feeling that doubly linked lists are more efficient than singly linked lists, and quantify the efficiency gap in a read-only situation. We further analyze the number of points of access into the list (pointers) necessary for obtaining a desired value of ϵ. We obtain tight tradeoffs which also separate the amortized and worst-case settings.Our upper bound implies that read-only programs with singly-linked input can do string matching much faster than previously expected.
Automatic test-based assessment of programming
Authors: Douce Christopher , Livingstone David , Orwell James
Published: October 2006

Systems that automatically assess student programming assignments have been designed and used for over forty years. Systems that objectively test and mark student programming work were developed simultaneously with programming assessment in the computer science curriculum. This article reviews a number of influential automatic assessment systems, including descriptions of the earliest systems, and presents some of the most recent developments. The final sections explore a number of directions automated assessment systems may take, presenting current developments alongside a number of important emerging e-learning specifications.
Roller coaster
Authors: Wing Michael
Published: October 2006

Sometimes, debugging reminds me of a sine wave, you know, the 5 stages of grief, followed by the 5 stages of the fix. Today is a 7-out-of-10-green-lights-on-the-way-to-work kind of day. I'm feeling fine, not great, not bad, just cruising along, when my project manager hands me a bug report.
Optimizing subroutines with optional parameters in F90 via function cloning
Authors: Das Dibyendu
Published: October 2006

Optional parameters are a feature of Fortran90. The objective of this feature is to allow the F90 programmer to declare a subroutine using a number of arguments and specify a subset of these parameters as
optional
, which in turn, allows the programmer to omit any of these optional parameters during invocation of the subroutine. The body of such a subroutine uses an F90 intrinsic function called
present()
, to test whether an optional parameter has meaningful values at run-time. The optional parameter can be written/read if and only if
present()
returns a true value. In this work, we describe a mechanism by which such subroutines which use optional parameters can be efficiently optimized using function cloning or specialization. Function Cloning is a well-known optimization technique that creates multiple copies of a function
f()
, in order to exploit better optimization opportunities. We will show how cloning/specialization can be utilized such that all calls to
present()
can be totally eliminated in the body of such subroutines. Cloning will also result in optimization opportunities not exploitable in the original source.
An object-oriented framework for the development of scalable parallel multilevel preconditioners
Authors: Sala Marzio
Published: October 2006

We present the design of a high-performance object-oriented framework that enables the rapid development and usage of efficient, scalable, and portable implementations of multilevel preconditioners for distributed sparse real matrices, in both serial and (massively) parallel environments. The main feature of the proposed framework is the use of several programming paradigms for the different implementation layers, with a strong emphasis on object-oriented classes and operator overloading for the top layer, and optimized FORTRAN and C code for the layers underneath. We describe an implementation of the proposed framework that is based on the ML library, the algebraic multilevel preconditioning package of Trilinos, which supports state-of-the-art parallel smoothed aggregation methods, and can be used to define general algebraic and geometric multilevel and multigrid preconditioners and solvers. The article demonstrates that we can take advantage of object-oriented programming and operator overloading to obtain intuitive, easy-to-read, and easy-to-develop codes that are at the same time efficient and scalable. Several numerical experiments obtained on serial and parallel computers show that the overhead required by the object-oriented layer is very modest, therefore allowing developers to focus on the new algorithms they are developing and testing, rather than on implementation details.
Building objects out of Plato
Authors: Giguette Ray
Published: October 2006

If we analyze a program as we do a story, we might ask: "What is the author really saying?"
Envisioning the future of India's software services business
Authors: Cusumano Michael A.
Published: October 2006

Forecasting coming challenges for Indian software companies.
Performance debugging for distributed systems of black boxes
Authors: Aguilera Marcos K. , Mogul Jeffrey C. , Wiener Janet L. , Reynolds Patrick , Muthitacharoen Athicha
Published: October 2006

Many interesting large-scale systems are distributed systems of multiple communicating components. Such systems can be very hard to debug, especially when they exhibit poor performance. The problem becomes much harder when systems are composed of "black-box" components: software from many different (perhaps competing) vendors, usually without source code available. Typical solutions-provider employees are not always skilled or experienced enough to debug these systems efficiently. Our goal is to design tools that enable modestly-skilled programmers (and experts, too) to isolate performance bottlenecks in distributed systems composed of black-box nodes.We approach this problem by obtaining message-level traces of system activity, as passively as possible and without any knowledge of node internals or message semantics. We have developed two very different algorithms for inferring the dominant causal paths through a distributed system from these traces. One uses timing information from RPC messages to infer inter-call causality; the other uses signal-processing techniques. Our algorithms can ascribe delay to specific nodes on specific causal paths. Unlike previous approaches to similar problems, our approach requires no modifications to applications, middleware, or messages.
SHARP
Authors: Fu Yun , Chase Jeffrey , Chun Brent , Schwab Stephen , Vahdat Amin
Published: October 2006

This paper presents
Sharp
, a framework for secure distributed resource management in an Internet-scale computing infrastructure. The cornerstone of
Sharp
is a construct to represent cryptographically protected resource claims---promises or rights to control resources for designated time intervals---together with secure mechanisms to subdivide and delegate claims across a network of resource managers. These mechanisms enable flexible resource peering: sites may trade their resources with peering partners or contribute them to a federation according to local policies. A separation of claims into tickets and leases allows coordinated resource management across the system while preserving site autonomy and local control over resources.
Sharp
also introduces mechanisms for controlled, accountable oversubscription of resource claims as a fundamental tool for dependable, efficient resource management. We present experimental results from a
Sharp
prototype for PlanetLab, and illustrate its use with a decentralized barter economy for global PlanetLab resources. The results demonstrate the power and practicality of the architecture, and the effectiveness of oversubscription for protecting resource availability in the presence of failures.
Reusable software components
Authors: Levine Trudy
Published: October 2006

This column consists of our yearly listing of sources for reusable software components. As always, no recommendation or guarantee by this column is implied.
What’s on Your Hard Drive?
Authors: O'Hanlon Charlene
Published: October 2006

With the amount of software that now runs on remote servers accessed through a Web browser, however, we’re expanding our scope to include any of these thin client tools or services that you might find useful.
A Conversation with David Brown
Authors: O'Hanlon Charlene
Published: October 2006

This month Queue tackles the problem of system evolution. One key question is: What do developers need to keep in mind while evolving a system, to ensure that the existing software that depends on it doesn’t break? It’s a tough problem, but there are few more qualified to discuss this subject than two industry veterans now at Sun Microsystems, David Brown and Bob Sproull. Both have witnessed what happens to systems over time and have thought a lot about the introduction of successive technological innovations to a software product without undermining its stability or the software that depends on it.
A split-mask countermeasure for low-energy secure embedded systems
Authors: Gebotys Catherine H.
Published: October 2006

Future wireless embedded devices will be increasingly powerful, supporting many more applications, including one of the most crucial---security. Although many embedded devices offer more resistance to bus---probing attacks because of their compact size, susceptibility to power or electromagnetic analysis attacks must be analyzed. This paper presents a new split-mask countermeasure to thwart low-order differential power analysis (DPA) and differential EM analysis (DEMA). For the first time, real-power and EM measurements are used to analyze the difficulty of launching new third-order DPA and DEMA attacks on a popular low-energy 32-bit embedded ARM processor. Results show that the new split-mask countermeasure provides increased security without large overheads of energy dissipation, compared to previous research. With the emergence of security applications in PDAs, cell phones, and other embedded devices, low-energy countermeasures for resistance to low-order DPA/DEMA is crucial for supporting future enabled wireless internet.
PATAXÓ
Authors: Braganholo Vanessa P. , Davidson Susan B. , Heuser Carlos A.
Published: October 2006

XML has become an important medium for data exchange, and is frequently used as an interface to (i.e., a view of) a relational database. Although a lot of work has been done on querying relational databases through XML views, the problem of updating relational databases through XML views has not received much attention. In this work, we map XML views expressed using a subset of XQuery to a corresponding set of relational views. Thus, we transform the problem of updating relational databases through XML views into a classical problem of updating relational databases through relational views. We then show how updates on the XML view are mapped to updates on the corresponding relational views. Existing work on updating relational views can then be leveraged to determine whether or not the relational views are updatable with respect to the relational updates, and if so, to translate the updates to the underlying relational database.
Methods for the assessment of fused images
Authors: Dixon T. D. , Canga E. F. , Noyes J. M. , Troscianko T. , Nikolov S. G. , Bull D. R. , Canagarajah C. N.
Published: October 2006

The prevalence of image fusion---the combination of images of different modalities, such as visible and infrared radiation---has increased the demand for accurate methods of image-quality assessment. The current study used a signal-detection paradigm, identifying the presence or absence of a target in briefly presented images followed by an energy mask, which was compared with computational metric and subjective quality assessment results. In Study 1, 18 participants were presented with fused infrared-visible light images, with a soldier either present or not. Two independent variables, image-fusion method (averaging, contrast pyramid, dual-tree complex wavelet transform) and JPEG compression (no compression, low and high compression), were used in a repeated-measures design. Participants were presented with images and asked to state whether or not they detected the target. In addition, subjective ratings and metric results were obtained. This process was repeated in Study 2, using JPEG2000 compression. The results showed a significant effect for fusion but not compression in JPEG2000 images, while JPEG images showed significant effects for both fusion and compression. Subjective ratings differed, especially for JPEG2000 images, while metric results for both JPEG and JPEG2000 showed similar trends. These results indicate that objective and subjective ratings can differ significantly, and subjective ratings should, therefore, be used with care.
Serotonergic drugs and spinal cord transections indicate that different spinal circuits are involved in external urethral sphincter activity in rats
Authors: Chang Hui-Yi , Cheng Chen-Li , Chen Jia-Jin J. , de Groat William C.
Published: October 2006

Lower urinary tract function is regulated by spinal and supraspinal reflexes that coordinate the activity of the urinary bladder and external urethral sphincter (EUS). Two types of EUS activity (tonic and bursting) have been identified in rats. This study in urethane-anesthetized female rats used cystometry, EUS electromyography, spinal cord transection (SCT) at different segmental levels, and analysis of the effects of 5-HT1Areceptor agonist (8-OH-DPAT) and antagonist (WAY100635) drugs to examine the origin of tonic and bursting EUS activity. EUS activity was elicited by bladder distension or electrical stimulation of afferent axons in the pelvic nerve (pelvic-EUS reflex). Tonic activity evoked by bladder distension was detected in spinal cord-intact rats and after acute and chronic T8–9 or L3–4 SCT but was abolished after L6–S1 SCT. Bursting activity was abolished by all types of SCT except chronic T8–9 transection. 8-OH-DPAT enhanced tonic activity, and WAY100635 reversed the effect of 8-OH-DPAT. The pelvic-EUS reflex consisted of an early response (ER) and late response (LR) when the bladder was distended in spinal cord-intact rats. ER remained after acute or chronic T8–9 and L3–4 SCT, but was absent after L6–S1 SCT. LR occurred only in chronic T8–9 SCT rats where it was enhanced or unmasked by 8-OH-DPAT. The results indicate that spinal serotonergic mechanisms facilitate tonic and bursting EUS activity. The circuitry for generating different patterns of EUS activity appears to be located in different segments of the spinal cord: tonic activity at L6–S1 and bursting activity between T8–9 and L3–4.
PAX6 Suppresses the Invasiveness of Glioblastoma Cells and the Expression of the Matrix Metalloproteinase-2 Gene
Authors: Mayes Debra A. , Hu Yuanjie , Teng Yue , Siegel Eric , Wu Xiaosong , Panda Kishori , Tan Fang , Yung W.K. Alfred , Zhou Yi-Hong
Published: October 2006

Glioblastoma multiforme (GBM) is the most invasive brain tumor. We have previously reported that the transcription factor PAX6 suppresses the tumorigenecity of GBM cells. By an in vitro Matrigel invasion assay on two GBM cell lines stably transfected with wild-type and/or two mutant forms of PAX6, this study displays the first evidence that PAX6 inhibits the invasiveness of GBM cells and that the DNA-binding domain of PAX6 is required for this function. Using real-time quantitative reverse transcription-PCR (RT-PCR), gelatin zymography, and immunohistochemistry assays, the expression of the gene encoding matrix metalloproteinase-2 (MMP2) in GBM cell lines grown in vitro or in intracranial xenografts in nude mice was shown to be repressed by either stable or adenoviral-mediated overexpression of PAX6. Luciferase promoter assays revealed PAX6-mediated suppression of MMP2 promoter activity. Electrophoretic mobility shift assays showed direct binding of PAX6 to the MMP2 promoter. A significant reverse correlation (P < 0.05) occurred between PAX6 and MMP2 expression quantified by real-time quantitative RT-PCR in 41 GBMs, 43 anaplastic astrocytomas, and 7 adjacent normal tissues. Interestingly, the degree and significance of the reverse correlation increased after excluding astrocytomas, whereas it became insignificant after excluding GBMs. In GBM cells stably transfected with a dominant negative mutant PAX6 showing increased MMP2 expression and invasiveness, knock-down of MMP2 revealed that MMP2 is one of the PAX6 target genes mediating its suppression of invasion. Overall data delineated a mechanism for the suppressive function of PAX6 in GBM: suppression of cell invasion by repressing the expression of proinvasive genes such as MMP2. (Cancer Res 2006; 66(20): 9809-17)
Coordinated Functions of E-Cadherin and Transforming Growth Factor β Receptor II In vitro and In vivo
Authors: Andl Claudia D. , Fargnoli Brenton B. , Okawa Takaomi , Bowser Mark , Takaoka Munenori , Nakagawa Hiroshi , Klein-Szanto Andres , Hua Xianxin , Herlyn Meenhard , Rustgi Anil K.
Published: October 2006

In epithelial cells, E-cadherin plays a key role in cell-cell adhesion, and loss of E-cadherin is a hallmark of tumor progression fostering cancer cell invasion and metastasis. To examine E-cadherin loss in squamous cell cancers, we used primary human esophageal epithelial cells (keratinocytes) as a platform and retrovirally transduced wild-type and dominant-negative forms of E-cadherin into these cells. We found decreased cell adhesion in the cells expressing dominant-negative E-cadherin, thereby resulting in enhanced migration and invasion. To analyze which molecular pathway(s) may modulate these changes, we conducted microarray analysis and found up-regulation of transforming growth factor β receptor II (TβRII) in the wild-type E-cadherin-overexpressing cells, which was confirmed by real-time PCR and Western blot analyses. To investigate the in vivo relevance of this finding, we analyzed tissue microarrays of paired esophageal squamous cell carcinomas and adjacent normal esophagus, and we could show a coordinated loss of E-cadherin and TβRII in ∼80% of tumors. To determine if there may be an E-cadherin-dependent regulation of TβRII, we show the physical interaction of E-cadherin with TβRII and that this is mediated through the extracellular domains of E-cadherin and TβRII, respectively. In addition, TβRI is recruited to this complex. When placed in the context of three-dimensional cell culture, which reflects the physiologic microenvironment, TβRII-mediated cell signaling is dependent upon intact E-cadherin function. Our results, which suggest that E-cadherin regulates TβRII function, have important implications for epithelial carcinogenesis characterized through the frequent occurrence of E-cadherin and TβRII loss. (Cancer Res 2006; 66(20): 9878-85)
Relationships of Human Papillomavirus Type, Qualitative Viral Load, and Age with Cytologic Abnormality
Authors: Kovacic Melinda Butsch , Castle Philip E. , Herrero Rolando , Schiffman Mark , Sherman Mark E. , Wacholder Sholom , Rodriguez Ana C. , Hutchinson Martha L. , Bratti M. Concepción , Hildesheim Allan , Morales Jorge , Alfaro Mario , Burk Robert D.
Published: October 2006

Persistent cervical infections with carcinogenic human papillomaviruses (HPV) cause virtually all cervical cancer. Cytologic abnormalities are the manifestations of HPV infections used to identify women at risk. To compare the potential of the full range of anogenital HPV genotypes to induce cytopathic effects, we examined the influences of HPV type, viral load, and age on cytopathology among 1,222 women having a single HPV type at enrollment into a 10,000-woman population-based study in Costa Rica. Cervical specimens were tested for ∼40 HPV types by MY09/MY11 L1 primer PCR and type-specific dot blot hybridization. Types were organized by phylogenetic species and cancer risk. PCR signal strength served as a qualitative surrogate for viral load. Overall, 24.8% [95% confidence interval (95% CI), 22.4-27.3] of single prevalent HPV infections had concurrent abnormalities (atypical squamous cells or worse) ranging from 0.0% to 80.0% based on HPV type. Noncarcinogenic α3/α15 types, although highly prevalent, uncommonly caused cytologic abnormalities (13.1%; 95% CI, 9.8-17.0). In contrast, one quarter to nearly one half of infections with a single major carcinogenic species type (α9/α11/α7/α5/α6) produced abnormalities. Greater abnormalities were observed with increasing qualitative viral load of carcinogenic types; fewer abnormalities were observed among older women (>54 years). A high percentage (46.2%) of detected abnormalities in women infected with HPV16 or related α9 types were high grade or worse, consistent with strong carcinogenicity, compared with 10.7% in women infected with α7 types, including HPV18, a major cause of adenocarcinoma. The lack of evident severe abnormalities associated with HPV18 and related HPV types might have implications for screening for poorly detected glandular and α7-related lesions. (Cancer Res 2006; 66(20): 10112-9)
Subcellular Trafficking of the Amyloid Precursor Protein Gene Family and Its Pathogenic Role in Alzheimer’s Disease
Authors: Kins Stefan , Lauther Nadine , Szodorai Anita , Beyreuther Konrad
Published: October 2006

Changes in the intracellular transport of amyloid precursor protein (APP) affect the extent to which APP is exposed to α- or β-secretase in a common subcellular compartment and therefore directly influence the degree to which APP undergoes the amyloidogenic pathway leading to generation of β-amyloid. As the presynaptic regions of neurons are thought to be the main source of β-amyloid in the brain, attention has been focused on axonal APP trafficking. APP is transported along axons by a fast, kinesin-dependent anterograde transport mechanism. Despite the wealth of in vivo and in vitro data that have accumulated regarding the connection of APP to kinesin transport, it is not yet clear if APP is coupled to its specific motor protein via an intracellular interaction partner, such as the c-Jun N-terminal kinase-interacting protein, or by yet another unknown molecular mechanism. The cargo proteins that form a functional complex with APP are also unknown. Due to the long lifespan, and vast extent, of neurons, in particular axons, neurons are highly sensitive to changes in subcellular transport. Recent in vitro and in vivo studies have shown that variations in APP or tau affect mitochondrial and synaptic vesicle transport. Further, it was shown that this axonal dysfunction might lead to impaired synaptic plasticity, which is crucial for neuronal viability and function. Thus, changes in APP and tau expression may cause perturbed axonal transport and changes in APP processing, contributing to cognitive decline and neurodegeneration in Alzheimer’s disease.
"Munājayāt Al-Sab'īn" ("Orisons of the Seventies"): 'Azīz Al-Sayyid Jāsim's Latest Prose Poems
Authors: El-Hage George
Published: October 2006

This short introductory essay focuses on the biographical and critical value of 'Azīz al-Sayyid Jāsim's short monologues or orisons that were printed posthumously in Arabic in 1994. The output of their author, 'Azīz al-Sayyid Jāsim, is enormous, especially in matters of ideology and literature. However, his poetic excursions are few: he never claimed them as central to his literary and cultural itinerary. Yet, as their publisher and editor in Arabic notes, these pieces offer new insights, not only in the record of an influential author, but also in his Sufi career, which led to his seclusion and eventual execution, despite his disinterest in active political involvement. The orisons have their depth, intimacy, and poetic power that integrate them into the scant, but significant, poetic tradition of the Sufis.
A "Salary" of Death: Aesthetics and Economy in Badr Shākir Al-Sayyāb's "Haffār Al-Qubūr" ("The Gravedigger")
Authors: Salama Mohammad
Published: October 2006

In one of modern Arabic literature's most genuinely pessimistic poems, "Haffār al-Qubūr" ("The Gravedigger"), Badr Shākir Sal-ayyāb depicts a shattered world seen from the perspective of a lascivious misanthropist who earns his living as a grave-digger. While a majority of critics have interpreted the poem in psychological terms as a reflection of al-Sayyāb's tormented ego, this paper offers a radically contextual deconstructionist reading that relates the gloomy condition of the poetic persona's life not merely to its author's personal sufferings, but to the socio-historical circumstances and economic conditions of the Iraqi society in the late 1940s and early 1950s. The fundamental postulate of this study is that although al-Sayyāb's poetry always revolves around personal and abstract issues, it reflects the economic reality of its time in a manner that is not just mimetic or reproductive of dominant ideologies, but deeply ironic and critical of the contradictions inherent in those very ideologies.
Pharmacokinetics, Safety, and Tolerability After Single and Multiple Oral Doses of Varenicline in Elderly Smokers
Authors: Burstein Aaron H. , Fullerton Terence , Clark David J. , Faessel Hélène M.
Published: October 2006

Varenicline is a novel selective α4β2 nicotinic acetylcholine partial agonist developed for smoking cessation. This study investigated the single‐ and multiple‐dose pharmacokinetics, safety, and tolerability of varenicline in elderly (≥ 65 years) smokers. Twenty‐four elderly smokers with normal renal function for their age (estimated creatinine clearance ≥ 70 mL/min) received varenicline 1 mg once daily (n = 8) or placebo (n = 4) for 7 days, or 1 mg twice daily (n = 8) or placebo (n = 4) for 6 days with a single dose on day 7 in a double‐blind, parallel group and placebo‐controlled design. There was no evidence of concentration‐ or time‐dependent changes in varenicline pharmacokinetics upon repeat dosing. Once‐ and twice‐daily dosing was associated with an approximate 2‐fold and 3‐fold increase, respectively, in systemic exposure to varenicline. Varenicline was well tolerated; all adverse events reported were mild to moderate in intensity. Thus, no dose adjustment is necessary based on age alone.