bluuebunny/crossref_metadata_2025 huggingface dataset:
Winning the KDD99 classification cup
Authors: Pfahringer Bernhard
Published: January 2007

We briefly describe our approach for the KDD99 Classification Cup. The solution is essentially a mixture of bagging and boosting. Additionally, asymmetric error costs are taken into account by minimizing the so-called
conditional risk
. Furthermore, the standard sampling with replacement methodology of bagging was modified to put a specific focus on the smaller but expensive-if-predicted-wrongly classes.
KDD-99 classifier learning contest LLSoft's results overview
Authors: Levin Itzhak
Published: January 2007

Kernel Miner is a new data-mining tool based on building the optimal decision forest. The tool won second place in the KDD99 Classifier Learning Contest, August 1999. We describe the Kernel Miner's approach and method used for solving the contest task. The received results are analyzed and explained.
Interface '99
Authors: Goodman Arnold
Published: January 2007

This personal overview of Interface '99 is intended to communicate its meaning and relevance to SIGKDD, as well as provide valuable information on trends within the Interface for data miners seeking to learn more about statistics. In addition, it is the newest link in a bridge between the Interface and KDD begun by References 2-4 and the sessions on KDD at Interface '98 and Interface '99.
Program synthesis by analogy
Authors: Ulrich John Wade , Moll Robert
Published: January 2007

By extending a given analogy, a known program which solves a given problem is converted to a program which solves a different but analogous problem. The domains of the two problems need not be the same but they must be related by an initial specified analogy. There are three features which distinguish the approach. First the analogy formation evolves gradually with the synthesis of the new program. Secondly the formation of the analogy is directed by the correctness proof of the known program. Finally the output of the synthesis process produces a correctness proof for the synthesized program.
Design rationale for TELOS, a PASCAL-based AI language
Authors: Travis Larry , Honda Masahiro , LeBlanc Richard , Zeigler Stephen
Published: January 2007

TELOS is a PASCAL-based AI language intended to facilitate efficient development of efficient, well-structured programs. The design emphasizes powerful data abstraction and control abstraction mechanisms rather than the provision of particular high-level constructs. Among the many capabilities of TELOS are those intended to make it especially suitable for systematic AI model building, for example, in the areas of knowledge representation, planning, and reasoning. An event facility is provided which unifies the handling of conditional interrupts (demons), process suspension, process communication and execution faults. The context-dependent TELOS data base is referenceable either associatively or directly.
AMORD explicit control of reasoning
Authors: Kleer Johan de , Doyle Jon , Steele Guy L. , Sussman Gerald Jay
Published: January 2007

The construction of expert problem-solving systems requires the development of techniques for using modular representations of knowledge without encountering combinatorial explosions in the solution effort. This report describes an approach to dealing with this problem based on making some knowledge which is usually implicitly part of an expert problem solver explicit, thus allowing this knowledge about control to be manipulated and reasoned about. The basic components of this approach involve using explicit representations of the control structure of the problem solver, and linking this and other knowledge manipulated by the expert by means of explicit data dependencies.
MobiCom poster
Authors: Wei Hung-yu , Gitlin Richard D.
Published: January 2007

The IP paging architecture in globally-connected mobile ad-hoc network is presented. Motivated by the energy-efficient design requirement in global-connected mobile ad-hoc network context, we design IP paging support in ad-hoc networks that is independent of, and compatible with, existing IP paging architectures. Two IP paging schemes: proactive paging and reactive paging are proposed. The system is implemented and evaluated with Network Simulator-2. In the reactive scheme, the system suffer less in paging delay and paging overhead. On the other hand, it is more energy-efficient in proactive scheme.
Resilient multicast using overlays
Authors: Banerjee Suman , Lee Seungjoon , Bhattacharjee Bobby , Srinivasan Aravind
Published: January 2007

We introduce PRM (Probabilistic Resilient Multicast): a multicast data recovery scheme that improves data delivery ratios while maintaining low end-to-end latencies. PRM has both a proactive and a reactive component; in this paper we describe how PRM can be used to improve the performance of application-layer multicast protocols, especially when there are high packet losses and host failures. Further, using analytic techniques, we show that PRM can guarantee arbitrarily high data delivery ratios and low latency bounds. As a detailed case study, we show how PRM can be applied to the NICE application-layer multicast protocol. We present detailed simulations of the PRM-enhanced NICE protocol for 10,000 node Internet-like topologies. Simulations show that PRM achieves a high delivery ratio (
>
97%) with a low latency bound (600 ms) for environments with high end-to-end network losses (1-5%) and high topology change rates (5 changes per second) while incurring very low overheads (
<
5%).
Incrementally improving lookup latency in distributed hash table systems
Authors: Zhang Hui , Goel Ashish , Govindan Ramesh
Published: January 2007

Distributed hash table (DHT) systems are an important class of peer-to-peer routing infrastructures. They enable scalable wide-area storage and retrieval of information, and will support the rapid development of a wide variety of Internet-scale applications ranging from naming systems and file systems to application-layer multicast. DHT systems essentially build an overlay network, but a path on the overlay between any two nodes can be significantly different from the unicast path between those two nodes on the underlying network. As such, the lookup latency in these systems can be quite high and can adversely impact the performance of applications built on top of such systems.In this paper, we discuss a random sampling technique that incrementally improves lookup latency in DHT systems. Our sampling can be implemented using information gleaned from lookups traversing the overlay network. For this reason, we call our approach
lookup-parasitic random sampling
(LPRS). LPRS is fast, incurs little network overhead, and requires relatively few modifications to existing DHT systems.For idealized versions of DHT systems like Chord, Tapestry and Pastry, we analytically prove that LPRS can result in lookup latencies proportional to the average unicast latency of the network, provided the underlying physical topology has a power-law latency expansion. We then validate this analysis by implementing LPRS in the Chord simulator. Our simulations reveal that LPRS-Chord exhibits a qualitatively better latency scaling behavior relative to unmodified Chord.Finally, we provide evidence which suggests that the Internet router-level topology resembles power-law latency expansion. This finding implies that LPRS has significant practical applicability as a general latency reduction technique for many DHT systems. This finding is also of independent interest since it might inform the design of latency-sensitive topology models for the Internet.
Internet intrusions
Authors: Yegneswaran Vinod , Barford Paul , Ullrich Johannes
Published: January 2007

Network intrusions have been a fact of life in the Internet for many years. However, as is the case with many other types of Internet-wide phenomena, gaining insight into the
global
characteristics of intrusions is challenging. In this paper we address this problem by systematically analyzing a set of firewall logs collected over four months from over 1600 different networks world wide. The first part of our study is a general analysis focused on the issues of distribution, categorization and prevalence of intrusions. Our data shows both a large quantity and wide variety of intrusion attempts on a daily basis. We also find that worms like CodeRed, Nimda and SQL Snake persist long after their original release. By projecting intrusion activity as seen in our data sets to the entire Internet we determine that there are typically on the order of 25B intrusion attempts per day and that there is an increasing trend over our measurement period. We further find that sources of intrusions are uniformly spread across the Autonomous System space. However, deeper investigation reveals that a very small collection of sources are responsible for a significant fraction of intrusion attempts in any given month and their on/off patterns exhibit cliques of correlated behavior. We show that the distribution of source IP addresses of the non-worm intrusions as a function of the number of attempts follows Zipf's law. We also find that at daily timescales, intrusion targets often depict significant spatial trends that blur patterns observed from individual "IP telescopes"; this underscores the necessity for a more global approach to intrusion detection. Finally, we investigate the benefits of shared information, and the potential for using this as a foundation for an automated, global intrusion detection framework that would identify and isolate intrusions with greater precision and robustness than systems with limited perspective.
Conductance and congestion in power law graphs
Authors: Gkantsidis Christos , Mihail Milena , Saberi Amin
Published: January 2007

It has been observed that the degrees of the topologies of several communication networks follow heavy tailed statistics. What is the impact of such heavy tailed statistics on the performance of basic communication tasks that a network is presumed to support? How does performance scale with the size of the network? We study routing in families of sparse random graphs whose degrees follow heavy tailed distributions. Instantiations of such random graphs have been proposed as models for the topology of the Internet at the level of Autonomous Systems as well as at the level of routers. Let
n
be the number of nodes. Suppose that for each pair of nodes with degrees

d
u

and

d
v

we have

O(d
u
d
v
)

units of demand. Thus the total demand is

O(n
2
)

. We argue analytically and experimentally that in the considered random graph model such demand patterns can be routed so that the flow through each link is at most

O(n log
2
n)

. This is to be compared with a bound

O(n
2
)

that holds for arbitrary graphs. Similar results were previously known for sparse random regular graphs, a.k.a. "expander graphs." The significance is that Internet-like topologies, which grow in a dynamic, decentralized fashion and appear highly inhomogeneous, can support routing with performance characteristics comparable to those of their regular counterparts, at least under the assumption of uniform demand and capacities. Our proof uses approximation algorithms for multicommodity flow and establishes strong bounds of a generalization of "expansion," namely "conductance." Besides routing, our bounds on conductance have further implications, most notably on the gap between first and second eigenvalues of the stochastic normalization of the adjacency matrix of the graph.
Fast accurate computation of large-scale IP traffic matrices from link loads
Authors: Zhang Yin , Roughan Matthew , Duffield Nick , Greenberg Albert
Published: January 2007

A matrix giving the traffic volumes between origin and destination in a network has tremendously potential utility for network capacity planning and management. Unfortunately, traffic matrices are generally unavailable in large operational IP networks. On the other hand, link load measurements are readily available in IP networks. In this paper, we propose a new method for practical and rapid inference of traffic matrices in IP networks from link load measurements, augmented by readily available network and routing configuration information. We apply and validate the method by computing backbone-router to backbone-router traffic matrices on a large operational tier-1 IP network -- a problem an order of magnitude larger than any other comparable method has tackled. The results show that the method is remarkably fast and accurate, delivering the traffic matrix in under five seconds.
CacheCOW
Authors: Goyal Pawan , Modha Dharmendra S. , Tewari Renu
Published: January 2007

Managed hosting and enterprise wide resource consolidation trends are increasingly leading to sharing of storage resources across multiple classes, corresponding to different applications/customers, each with a possibly different Quality of Service (QoS) requirement. To enable a storage system to meet diverse QoS requirements, we present two algorithms for dynamically allocating cache space among multiple classes of workloads. Our algorithms dynamically adapt the cache space allocated to each class in response to the observed response time, the temporal locality of reference, and the arrival pattern for each class. Using trace driven simulations collected from large storage system installations, we experimentally demonstrate that the algorithms not only meet the QoS requirements, but also increase the throughput by achieving a higher hit rate whenever feasible.
A Boolean array based algorithm in APL
Authors: Sullivan G , Fordyce F
Published: January 2007

This paper describes an algorithm for forward chaining in rule-based production expert systems which makes extensive use of array structures and Boolean operations, to which APL lends itself. Additionally, a short introduction is provided for the reader unfamiliar with expert systems.
Automated categorization in the international patent classification
Authors: Fall C. J. , Törcsvári A. , Benzineb K. , Karetka G.
Published: January 2007

A new reference collection of patent documents for training and testing automated categorization systems is established and described in detail. This collection is tailored for automating the attribution of international patent classification codes to patent applications and is made publicly available for future research work. We report the results of applying a variety of machine learning algorithms to the automated categorization of English-language patent documents. This procedure involves a complex hierarchical taxonomy, within which we classify documents into 114 classes and 451 subclasses. Several measures of categorization success are described and evaluated. We investigate how best to resolve the training problems related to the attribution of multiple classification codes to each patent document.
Management of wireless home networking technologies in the context of composite radio environments
Authors: Demestichas P. , Oikonomou A. , Vivier G. , Theologou M.
Published: January 2007

BRAN/WLAN systems are seen as promising solutions for covering residential, business, etc., environments, and therefore realising the wireless home/office concept. This paper presents management functionality for augmenting the exploitation of these systems, by making feasible their integration in a composite radio (CR) context. In the followed approach the first point will be to revisit the main features of a HiperLAN2 system. Next, will be the presentation of a general Service and Network Management System (SNMS) architecture. The last point will be the functionality of the SNMS components that are tailored to the managed HiperLAN2 technology. A set of resource management problems will be addressed, for exploiting HiperLAN2 networks in a CR context.
Using data mining techniques on Web access logs to dynamically improve hypertext structure
Authors: Masseglia F. , Poncelet P. , Teisseire M.
Published: January 2007

With the growing popularity of the World Wide Web (Web), large volumes of data such as user address or URL requested are gathered automatically by Web servers and collected in access log files. Discovering relationships and global patterns that exist in such files can provide significant and useful information for performance enhancement, restructuring a Web site for increased effectiveness, and customer targeting in electronic commerce. In this paper, we propose an integrated system (WebTool) for applying data mining techniques such as association rules or sequential patterns on access log files. Once interesting patterns are discovered, we illustrate how they can be used to customize the server hypertext organization dynamically.
Molecular computers
Authors: Conrad Michael
Published: January 2007

Programmability, evolvability, and efficiency are tied together by a tradeoff principle which may explain the radically different computational capabilities of biological systems and digital computers.
On the construction of effective vocabularies for information retrieval
Authors: Salton G. , Yu Clement T.
Published: January 2007

Natural language query formulations exhibit advantages over artificial language statements since they permit the user to approach the retrieval environment without prior training and without using intermediaries. To obtain adequate retrieval output, it is however necessary to emphasize the good terms and to deemphasize the bad ones. The usefulness of the terms in a natural language vocabulary is first characterized in terms of their frequency distribution over the documents of a collection. The construction of "good" natural language vocabularies is then described, and methods are given for improving the vocabulary by transforming terms that operate poorly for retrieval purposes into better ones.
Information retrieval and the query language
Authors: Waksman Abraham
Published: January 2007

This paper addresses itself to the information retrieval problem of a manager within an organization. We feel that the approach taken in specifying such a system is sufficiently general to be suitable for application to other system specifications. It is assumed that the manager wishes to interrogate a system containing a data base that relates to his task of making decisions in the course of running his part of an organization.To meet the manager's needs we have attempted to define the models a manager uses in making decisions. We have further made an approach toward problem definition for the manager.To interpret a manager's queries stemming from encountered or anticipated problems, we have attempted to define an inferential system. The inferential system has a further task of specifying the retrieval of information that might exist only in an implicit form. Finally, we demonstrate an approach toward the design of a query language for the manager, which could become "natural" to him after short experience.
Computer assisted communication system
Authors: Ackerman J. T. , Dorris H. N. , Hagelbarger D. , Shannon M. J.
Published: January 2007

This paper describes a continuing series of experiments aimed at providing improved communications for non-vocal, motion-impaired people. Special keyboards, coupled with a computer which permits one or two keystrokes to call out a complete phrase, have been enthusiastically used by children at the United Cerebral Palsy Association in Edison, New Jersey. After a brief review of previous systems, the current one, which uses a stand-alone microcomputer, is described.
Discovering knowledge in DNA and protein data
Authors: Holder Lawrence
Published: January 2007

This research investigates a method for discovering knowledge in structural data. We have implemented the SUBDUE substructure discovery system which discovers interesting and repetitive subgraphs in a labeled graph representation using the minimum description length principle. Experiments have shown SUBDUE's applicability in a variety of domains. We are currently applying SUBDUE to both DNA and protein data from the Brookhaven PDB, where SUBDUE was able to find patterns in secondary structure that are both characteristic and unique to categories of proteins, such as hemoglobin and myoglobin. Ultimately, we plan to use SUBDUE to find structural patterns in functional groups of proteins and the boundaries of genes in DNA.
Public health surveillance using association rules
Authors: Jones Warren T.
Published: January 2007

A multidisciplinary group is carrying out knowledge discovery research with researchers from computer science, pathology and biostatistics in collaboration with the Medical Informatics Section of the Department of Medicine. The current focus is on healthcare applications, more specifically on surveillance problems. A tool called Hawkeye (renamed Data Mining Surveillance System - DMSS) has been developed which searches temporally organized medical data, builds associations and applies interestingness heuristics for the identification of trends of interest to medical domain experts. The research also involves the study of collaborative interpretation of the identified patterns and trends.
Similarity measures of RNA structures
Authors: Horvath Tamas
Published: January 2007

Untranslated regions of (pre-) mRNAs contain regulatory elements called signal structures to control gene expression at the posttranscriptional level. Their regulatory information is encoded in their primary and secondary structures. Given a set of known signal structures belonging to several classes, our aim is to find a) the presence of signal structures belonging to known classes on uncharacterized mRNA, and b) uncharacterized signal structure classes. We have applied relational instance-based method for the first problem.
On the average sojourn time under M/M/1/SRPT
Authors: Bansal Nikhil
Published: January 2007

We consider an M/M/1 queueing system under the Shortest Remaining Processing Time (SRPT) policy. We show that there are constants
c
l
and
c
2
such the average sojourn time under SRPT lies between
c
l
(μ(1 - ρ) log 1/(1 - ρ))
-1
and
c
2
(μ(l - ρ) log 1/(1 - ρ))
-1
, where μ denotes the service rate and ρ denotes the load. Comparing this with the classic result that any scheduling policy that does not use the knowledge of job sizes has average sojourn time (μ(1-ρ))
-1
, implies that SRPT offers a non-constant improvement over such policies.
Exploratory medical knowledge discovery
Authors: Roddick John F. , Fule Peter , Graco Warwick J.
Published: January 2007

The application of data mining and knowledge discovery techniques to medical and health datasets is a rewarding but highly challenging area. Not only are the datasets large, complex, heterogeneous, hierarchical, time-varying and of varying quality but there exists asubstantial medical knowledge base which demands a robust collaboration between the data miner and the health professional(s) if useful information is to be extracted.This paper presents the experiences of the authors and others in applying exploratory data mining techniques to medical, health and clinical data. In so doing, it elicits a number of general issues and provides pointers to possible areas of future research in data mining and knowledge discovery more broadly.
A survey of kernels for structured data
Authors: Gärtner Thomas
Published: January 2007

Kernel methods in general and support vector machines in particular have been successful in various learning tasks on data represented in a single table. Much 'real-world' data, however, is structured - it has no natural representation in a single table. Usually, to apply kernel methods to 'real-world' data, extensive pre-processing is performed to embed the data into areal vector space and thus in a single table. This survey describes several approaches of defining positive definite kernels on structured instances directly.
Biological applications of multi-relational data mining
Authors: Page David , Craven Mark
Published: January 2007

Biological databases contain a wide variety of data types, often with rich relational structure. Consequently multi-relational data mining techniques frequently are applied to biological data. This paper presents several applications of multi-relational data mining to biological data, taking care to cover a broad range of multi-relational data mining techniques.
Prospects and challenges for multi-relational data mining
Authors: Domingos Pedro
Published: January 2007

This short paper argues that multi-relational data mining has a key role to play in the growth of KDD, and briefly surveys some of the main drivers, research problems, and opportunities in this emerging field.
Integration of data base design in programming languages
Authors: Amble Tore
Published: January 2007

In 1978, the ASTRA research group at the University of Trondheim was formed to create a prototype of a relational data base machine with appropriate software. A major part of this development was the definition and implementation of an integrated data definition and manipulation language ASTRAL (1).
Data and activities
Authors: Borgida Alexander T. , Greenspan Sol
Published: January 2007

We wish to briefly discuss recent work in conceptual modelling from a slightly different point of view in order to highlight the parallels between data and transactions, and then mention some benefits of this view.

A time-honoured way of describing a system (portion of the world) is by positing a domain of objects and then inter-relating them through function and predicate symbols. The resulting description is a set of axioms in a FOPC. If the world is dynamic, one usually augments the description with the notion of time or state, in which case axioms can be divided naturally into “general laws” (heretofore
constraints
) holding in all states, and state-specific “facts”. Given states, one then also has the ability to describe state transitions (
events
) as predicates on pairs of states or, as shown below, as objects in their own right.
Data models in database management
Authors: Codd E. F.
Published: January 2007

It is a combination of three components: 1) a collection of data structure types (the building blocks of any database that conforms to the model);

2) a collection of operators or inferencing rules, which can be applied to any valid instances of the data types listed in (1), to retrieve or derive data from any parts of those structures in any combinations desired;

3) a collection of general integrity rules, which implicitly or explicitly define the set of consistent database states or changes of state or both—these rules may sometimes be expressed as insert-update-delete rules.
Data abstraction tools
Authors: Schmidt Joachim W.
Published: January 2007

Current research in data modeling is motivated by the following dilemma:

- At the
application
level - being confronted with “slices of reality” - details are perceived that, in general, cannot be represented.

- At the
representation
level - being confronted with “levels of machines” - details are represented that, in general, cannot be perceived.

Abstraction methods cope with that problem by suppressing unnecessary details and by formalizing and structuring the relevant information.
Abstraction, data types, and models for software
Authors: Shaw Mary
Published: January 2007

In the area of software development and maintenance, a major issue is managing the complexity of the systems. Programming methodologies and languages to support them have grown in response to new ideas about how to cope with this complexity. A dominant theme in the growth of methodologies and languages is the development of tools dealing with abstractions. An
abstraction
is a simplified description, or
specification
, of a system that emphasizes some of its details or properties while suppressing others. A
good
abstraction is one in which information that is significant to the reader (i.e., the user) is emphasized while details that are immaterial, at least for the moment, are suppressed.

What we call “abstraction” in programming systems corresponds closely to what is called “modelling” in many other fields. It shares many of the same problems deciding which characteristics of the system are important, what variability (i.e., parameters) should be included, which descriptive formalism to use, how the model can be validated, and so on
Challenging interfaces/redesigning users
Authors: Dickinson Anna , Eisma Roos , Gregor Peter
Published: January 2007

As the identity of the computer user becomes more diverse, software developers can no longer assume familiarity with legacy systems or perfect vision, motor control and memory. The development of Piloot (for users with learning difficulties) and SeeWord (for dyslexic readers) shows that systems can be usable and accessible for 'non-typical' user groups. It is no longer appropriate to design 'general purpose' software that excludes users because of their age or minor impairments. Piloot and SeeWord, although developed for very different user groups, uncover some common barriers to computer use. Although some of these barriers were overcome in similar ways, other solutions were specific to the target user group and this may suggest strategies that will be effective in developing inclusive systems in the future.
Abstract user interface representations
Authors: Trewin Shari , Zimmermann Gottfried , Vanderheiden Gregg
Published: January 2007

This paper examines four XML languages for abstract user interface representation: UIML, XIML, XForms and AIAP. It discusses whether the high level architectures of these languages support the requirements of universal usability by allowing use of personal interfaces. Specific technical requirements include separation of data from presentation, explicit declarative representation of interface elements, their state, dependencies, and semantics, flexibility in inclusion of alternative resources and support for remote control and different interaction styles. Of the languages examined, XForms and AIAP provide the best match to the requirements. While XForms requires an appropriate delivery context to provide full access, the AIAP standard will include specification of the context in which the language is to be used.
Context-aware communication for severely disabled users
Authors: Davis Adriane B. , Moore Melody M. , Storey Veda C.
Published: January 2007

Even with assistive communication technology, interactive conversation is extremely difficult for users with severely limited mobility and loss of speech. Input to such devices is painfully slow and subject to high error rates with the resulting output not reliably reflecting the true intentions of the user. Conversational prediction has been incorporated into assistive systems to help speed up communication but could be further improved by considering the contextual interaction between the user and conversant. Contextual information applied to user profiles can greatly enhance conversational prediction and increase a severely disabled user's control over his or her complex world. We present a framework that integrates a rich profile of the user, a model of the user's environment, and actors on that environment. To test the validity of the framework, we develop a set of profiles and apply them in two different scenarios. Initial results show that the context-aware user profiles can increase both the accuracy and speed of the communication.
Sink-to-sensors reliability in sensor networks
Authors: Park Seung-Jong , Sivakumar Raghupathy
Published: January 2007

The issue of relability, thus far, has not been addressed throughly to any extent in sensor networking research. To the best of our knowledge the first such work that focused on some aspect of reliable communication in sensor networks appeared only in [1]. In this paper, we focus on the problem of communication reliability from the sink to the sensors in a static network.
Hierarchical grid location management for large wireless Ad hoc networks
Authors: Philip Sumesh J. , Qiao Chunming
Published: January 2007

Recently, a new family of protocols has been introduced for large scale ad hoc networks that make use of the approximate location of nodes in the network for geographic routing. Location management plays an important role in such protocols, and in this paper, we propose a deterministic hierachical scheme for managing the location information of nodes, and analyze the cost of such a scheme via probabilistic means and simulations. We find that the cost of hierarchical location management has an asymptotic overhead cost of O(ν N log
2
N) for location registration, which is asymptotically lower than the location management overhead in protocols described in literature, and thus scales well with the increase in the number of nodes in the network.
Optimizing tree reconfiguration to track mobile targets in sensor networks
Authors: Zhang Wensheng , Cao Guohong
Published: January 2007

Most existing work on sensor networks concentrates on finding efficient ways to forward data from the information source to the data centers, and not much work has been done on collecting local data and generating the data report. This paper studies this issue by proposing energy efficient techniques to detect and track a mobile target. We introduce the concept of dynamic convoy treebased collaboration (DCTC), and formalize it as an optimization problem which needs to find a convoy tree sequence with low energy consumption. We slove the optimization problem in two steps. First, we propose an interception-based reconfiguration algorithm, which can reconfigure the tree structure in an energy efficient way. Second, we develop a theoretical network model, based on which we propose an optimal method for root migration. Extensive experiments are conducted to verify the effectiveness of the proposed method for root migration, and to evaluate and compare the performance of various tree reconfiguration schemes which use different root migration methods and tree reconfiguration algorithms. The results show that the developed optimal method for root migration matches the analytical results, and the tree reconfiguration scheme using the optimal root migration method and the interception-based reconfiguration algorithm has the lowest energy consumption.
Topology properties of Ad hoc networks with random waypoint mobility
Authors: Bettstetter Christian
Published: January 2007

Given is a wireless multihop network with n nodes moving according to the random waypoint model on a system area of size A. Each node has a fixed transmission range r0. We derive a closed-form approximation for the critical (r0, n)-pairs that are needed to keep the mobile network connected during at least P(con)=99% of the time. In addition, we calculate the average degree μ experienced by a node during its movement and the node-to-node distance distribution f s(s).
Microcomputer-aided eating for the severely handicapped
Authors: Ramey R. L. , Aylor J. H. , Williams R. D.
Published: January 2007

Computer control of manipulators and machine tools is a highly developed technology; however, where space, cost, and power are limited, there is a continuing demand for simple but effective digital control systems capable of modest accuracy. We have developed a versatile system which permits severely handicapped individuals to eat independently, using a microcomputer-controlled manipulator. We did not select the method of trajectory computing using coordinate transformations because of the computational load, and resulting reduced sampling rate, imposed on the computer. We instead used a "learning phase" to establish the point-to-point coordinates of the motion, regardless of the coordinate system in which the manipulator resides.The system described here permits quadriplegics to direct the movements of a four-degree-of-freedom manipulator. A compact microcomputer, designed around the Intel 8080, controls the system.
Teaching programming to the deaf
Authors: Ross Rockford J.
Published: January 2007

For certain groups of handicapped persons the field of computer science offers challenging, high-paying careers which are more accessible than other careers. Programming can be done at cathode ray tube terminals which provide a dynamic, visual environment needed by the hearing impaired, and which can be placed in locations convenient to those with mobility impairments. Unfortunately, most colleges and universities are not prepared to teach such students, particularly the deaf. In this paper an ongoing research project to design an online, dynamic, student-controlled library of programming language examples for use in teaching programming languages is described. This system promises to be useful in meeting the needs of handicapped students.
A performance comparison of Mobile IPv6, Hierarchical Mobile IPv6, fast handovers for Mobile IPv6 and their combination
Authors: Pérez-Costa Xavier , Torrent-Moreno Marc , Hartenstein Hannes
Published: January 2007

Mobile IP, the current IETF proposal for IP mobility support, represents a key element for future
All-IP
wireless networks to provide service continuity while on the move within a multi-access environment. We conducted a performance evaluation of Mobile IPv6 and its proposed enhancements, i.e., Fast Handovers for Mobile IPv6, Hierarchical Mobile IPv6 and our proposed combination of them, using the network simulator ns-2 for the case of a 'hot spot' deployment scenario. The simulation scenario comprises four access routers and up to 50 mobile nodes that communicate in accordance with the IEEE 802.11 wireless LAN standard. The study provides quantitative results of the performance improvements obtained by the proposed enhancements as observed by a single mobile user with respect to handoff latency, packet loss rate and achieved bandwidth per station. As a complementary part of the study, the signaling load costs associated with the performance improvements provided by the enhancements has been analyzed. The simulation environment allowed us also to investigate the behavior of the protocol in extreme cases, e.g., under channel saturation conditions and considering different traffic sources: CBR, VoIP, Video and TCP transfers. While some simulation results corroborate the intention of the protocols specifications, other results give insights not easily gained without performing simulations. This study provides a deep understanding of the overall performance of the various protocols and supports the design process of a Mobile IPv6-based network when a decision of whether it is appropriate to implement any of the proposed Mobile IPv6 enhancements has to be made.
Lifetime packet discard for efficient real-time transport over cellular links
Authors: Gurtov Andrei , Ludwig Reiner
Published: January 2007

Mobile cellular users often experience significant delay jitter that undermines quality of real-time applications. Delay jitter can cause unnecessary delivery of stale packets with passed playback deadline and duplicate packets retransmitted by the end host after experiencing a timeout. With Lifetime Packet Discard (LPD) a flow adaptive link can tailor the trade-off between the maximum delay jitter and reliability if quality of service requirements of a flow are known. We propose using an IP option to communicate the flow requirements to the link layer. The packet lifetime is set to the minimum of the data lifetime determined by application and the retransmit timeout value determined by the transport protocol if selective reliability is supported. For congestion-responsive flows, the link transmits only headers of expired packets to prevent unnecessary triggering of end-to-end congestion control. Our simulations show that LPD is efficient in reducing stale data delivery and increases the number of packets delivered in time for real-time flows. For semi-reliable flows throughput and goodput are improved because duplicate packet delivery is prevented.
Instance-based networking
Authors: Youssef Moustafa , Elsayed Tamer , Hussein Mohamed , Nadeem Tamer , Youssef Adel , Iftode Liviu
Published: January 2007

In this work we consider the design principles of the Instance-Based Network (IBN), an extended version of a generic Content-Based Network (CBN). IBN acts as an overlay communication platform over which end-point entities, called contents, communicate independently from their physical locations while providing the flexibility of having different instances of the same content. The semantics of different instances are assigned by the application using the IBN. Routing in the IBN is instance-based; the IBN can route a message to a specific content instance or to the closest instance, if no exact match is found for the destination content instance.
QEPCAD B
Authors: Brown Christopher W.
Published: January 2007

This report introduces Q
EPCAD
, B, a program for computing with real algebraic sets using cylindrical algebraic decomposition (CAD). QEPCAD B both extends and improves upon the Q
EPCAD
system for quantifier elimination by partial cylindrical algebraic decomposition written by Hoon Hong in the early 1990s. This paper briefly discusses some of the improvements in the implementation of CAD and quantifier elimination via CAD, and provides somewhat more detail on extensions to the system that go beyond quantifier elimination. The author is responsible for most of the extended features of Q
EPCAD
B, but improvements to the basic CAD implementation and to the SACLIB library on which Q
EPCAD
is based are the results of many people's work, including: George E. Collins, Mark J. Encarnación, Hoon Hong, Jeremy Johnson, Werner Krandick, Richard Liska, Scott McCallum, Nicolas Robidoux, and Stanly Steinberg. Source code, documentation and installation instructions for QEPCAD B are all available at www.cs.usna.edu/~qepcad.
Memory cache and lisp
Authors: Fateman Richard
Published: January 2007

The speed of modern computers can be increased by organizing computations so that memory access patterns correspond more closely to the memory cache-loading patterns implemented in the hardware. Rearranging code and data are each possible. Here we concentrate on automatic rearrangement of data, and examine the belief, common in some technical circles, that modern generational copying garbage collectors (GC) will improve data caching by relocating and compressing data, as a matter of normal processing. Since GC routines tend to be very well-tested and quite robust, if this belief can be confirmed by benchmarks, a GC could be a "free" way of reliably speeding up programs
in practice
.In fact, our tests show this speedup phenomenon can be measured in some but not all sample Lisp programs. A novelty in our tests (at least when this paper was written) was using a full Lisp system linked to free software (PAPI) to access hardware machine registers. PAPI allows us to count cache misses during full-speed computation. We conclude that after a GC cache misses may be significantly reduced in some examples. Reorganization by GC speeds up computation by as much by a factor of 4, but in some cases the effect is negligible (or may even slow computation slightly). In any case, no extra effort is required of the programmer or user to take advantage of the potential speedup.
Handling context-sensitive syntactic issues in the design of a front-end for a MATLAB compiler
Authors: Joisha Pramod G. , Kanhere Abhay , Banerjee Prithviraj , Shenoy U. Nagaraj , Choudhary Alok
Published: January 2007

In recent times, the MATLAB language has emerged as a popular alternative for programming in diverse application domains such as signal processing and meteorology. The language has a powerful array syntax with a large set of pre-defined operators and functions that operate on arrays or array sections, making it an ideal candidate for applications involving substantial array-based processing.Yet, for all the programming convenience that the language offers, designing a parser and scanner capable of mimicking the language's syntax has proven to be an acutely difficult task. The language has many context-sensitive constructions, and though numerous front-end implementations of MATLAB and MATLAB-like languages exist, not much has been discussed regarding the efficient compile-time parsing of such languages or how its syntax impacts the parsing process.In this paper, we present the design and implementation of a compiler front-end for the MATLAB language. We discuss in detail both the indigenously designed grammar responsible for syntax analysis as well as the lexical specification that complements the grammar. In the course of our attempts to emulate MATLAB's syntax, we were able to unravel certain key issues relating to its syntax, such as the complications arising in parsing command-form function invocations within a compile-time environment, the context-sensitive interpretation of the single quote character, and the translation of white space within matrices into element separators.The front-end effects a conversion of the original source to an intermediate form in which statements are represented as abstract syntax trees and the flow of control between statements by a control-flow graph. All subsequent compiler passes work on this intermediate representation.The front-end was designed and implemented as part of the MATCH project, which addresses the translation of a MATLAB program by a compiler onto a heterogeneous target consisting of embedded and commerical-off-the-shelf processors.
A performance comparison of dynamic Web technologies
Authors: Titchkosky Lance , Arlitt Martin , Williamson Carey
Published: January 2007

Today, many Web sites dynamically generate responses "on the fly" when user requests are received. In this paper, we experimentally evaluate the impact of three different dynamic content technologies (Perl, PHP, and Java) on Web server performance. We quantify achievable performance first for static content serving, and then for dynamic content generation, considering cases both with and without database access. The results show that the overheads of dynamic content generation reduce the peak request rate supported by a Web server up to a factor of 8, depending on the workload characteristics and the technologies used. In general, our results show that Java server technologies typically outperform both Perl and PHP for dynamic content generation, though performance under overload conditions can be erratic for some implementations.
Is remote host availability governed by a universal law?
Authors: Douceur John R.
Published: January 2007

The availability of peer-to-peer and other distributed systems depends not only on the system architecture but also on the availability characteristics of the hosts participating in the system. This paper constructs a model of remote host availability, derived from measurement studies of four host populations. It argues that hosts are incompletely partitioned into two behavioral classes, one in which they are cycled on/off periodically and one in which they are nominally kept on constantly. Within a class, logarithmic availability generally follows a uniform distribution; however, the underlying reason for this is not readily apparent.
Accessibility standards for operating systems
Authors: Goldthwaite John
Published: January 2007

The Accessibility Working Group has been created by the Free Standards Group to develop accessibility standards that will enable universal access to computer systems, applications, and services. The Accessibility Working Group is developing a set of accessibility standards within the Linux Standard Base with the goals of improving overall accessibility of Open Source LSB platforms.