DEPARTMENT: Hello world
Efficient sensor placement for environmental monitoring
By Marinka Zitnik, March 2014
Articles Tagged: Design
Articles & Features
Cloud computing in plain English
By Ryan K. L. Ko, March 2010
Volunteer computing
Computers continue to get faster exponentially, but the computational demands of science are growing even faster. Extreme requirements arise in at least three areas.
By David P. Anderson, March 2010
Clouds at the crossroads
Despite its promise, most cloud computing innovations have been almost exclusively driven by a few industry leaders, such as Google, Amazon, Yahoo!, Microsoft, and IBM. The involvement of a wider research community, both in academia and industrial labs, has so far been patchy without a clear agenda. In our opinion, the limited participation stems from the prevalent view that clouds are mostly an engineering and business-oriented phenomenon based on stitching together existing technologies and tools.
By Ymir Vigfusson, Gregory Chockler, March 2010
Scientific workflows and clouds
In recent years, empirical science has been evolving from physical experimentation to computation-based research. In astronomy, researchers seldom spend time at a telescope, but instead access the large number of image databases that are created and curated by the community [42]. In bioinformatics, data repositories hosted by entities such as the National Institutes of Health [29] provide the data gathered by Genome-Wide Association Studies and enable researchers to link particular genotypes to a variety of diseases.
By Gideon Juve, Ewa Deelman, March 2010
The cloud at work
By Sumit Narayan, Chris Heiden, March 2010
State of security readiness
Cloud computing is a model for enabling convenient, on-demand network access to a shared pool of configurable computing resources that can be rapidly provisioned and released with minimal management effort or service provider interaction. With this pay-as-you-go model of computing, cloud solutions are seen as having the potential to both dramatically reduce costs and increase the rapidity of development of applications.
By Ramaswamy Chandramouli, Peter Mell, March 2010
The business of clouds
At the turn of the 20th century, companies stopped generating their own power and plugged into the electricity grid. In his now famous book The Big Switch, Nick Carr analogizes those events of a hundred years ago to the tectonic shift taking place in the technology industry today.
By Guy Rosen, March 2010
Staying disciplined during an interdisciplinary degree
By Daniel W. Goldberg, December 2009
Social learning and technical capital on the social web
The social Web is a set of ties that enable people to socialize online, a phenomenon that has existed since the early days of the Internet in environments like IRC, MUDs, and Usenet (e.g. 4, 12). People used these media in much the same way they do now: to communicate with existing friends and to meet new ones. The fundamental difference was the scale, scope, and diversity of participation.
By Sarita Yardi, December 2009
Grafitter
"Know thyself". Carved in stone in front of the Temple of Apollo at Delphi, that was the first thing people saw when they visited the Oracle to find answers. The benefits of knowing oneself are many. It fosters insight, increases self-control, and promotes positive behaviors such as exercise and energy conservation.
By Ian Li, Anind Dey, Jodi Forlizzi, December 2009
Privacy challenges and solutions in the social web
Research related to online social networks has addressed a number of important problems related to the storage, retrieval, and management of social network data. However, privacy concerns stemming from the use of social networks, or the dissemination of social network data, have largely been ignored. And with more than 250 million active Facebook (http://facebook.com) users, nearly half of whom log in at least once per day [5], these concerns can't remain unaddressed for long.
By Grigorios Loukides, Aris Gkoulalas-Divanis, December 2009
Are your friends who they say they are?
How sure are you that your friends are who they say they are? In real life, unless you are the target of some form of espionage, you can usually be fairly certain that you know whom your friends are because you have a history of shared interests and experiences. Likewise, most people can tell, just by using common sense, if someone is trying to sell them on a product, idea, or candidate. When we interact with people face-to-face, we reevaluate continuously whether something just seems off based on body language and other social and cultural cues.
By Roya Feizy, Ian Wakeman, Dan Chalmers, December 2009
Don't ask me
Searching for information online has become an integral part of our everyday lives. However, sometimes we don't know the specific search terms to use, while other times, the specific information we're seeking hasn't been recorded online yet.
By Gary Hsieh, December 2009
Dynamic displays
While touchscreens allow extensive programmability and have become ubiquitous in today's gadgetry, such configurations lack the tactile sensations and feedback that physical buttons provide. As a result, these devices require more attention to use than their button-enabled counterparts. Still, the displays provide the ultimate interface flexibility and thus afford a much larger design space to application developers.
By Chris Harrison, Scott Hudson, September 2009
Server virtualization architecture and implementation
Virtual machine technology, or virtualization, is gaining momentum in the information technology community. While virtual machines are not a new concept, recent advances in hardware and software technology have brought virtualization to the forefront of IT management. Stability, cost savings, and manageability are among the reasons for the recent rise of virtualization. Virtual machine solutions can be classified by hardware, software, and operating system/containers. From its inception on the mainframe to distributed servers on x86, the virtual machine has matured and will play an increasing role in systems management.
By Jeff Daniels, September 2009
Introduction
By Justin Solomon, June 2009
LibraryThing
By Anna Ritchie, June 2009
Courier problems
Courier problems comprise a set of recently proposed combinatorial optimization problems, which are inspired by some novel requirements in railway wagon scheduling. In these problems, scheduling strategies of some mobile couriers are considered. These mobile couriers initially reside at some fixed location. They are assigned some duties of commodity transfer between different pairs of locations. The scenario may be static or dynamic. The motivation is to optimize the movement of the couriers over the constraint of the traversed path or the associated cost. We discuss here some varieties of the courier problems formalized on graphs and address the potential methods of their solution.
By Malay Bhattacharyya, June 2009
An overview of privacy preserving data mining
By Aris Gkoulalas-Divanis, Vassilios S. Verykios, June 2009
HCI and theology
By Steve Clough, March 2009
State considerations in distributed systems
By Daniel W. Goldberg, March 2009
AmazonViz
This article describes a technique to visualize query results, representing purchase orders placed on Amazon.com, along a traditional 2-D scatter plot and a space-filling spiral. We integrate 3-D objects that vary their spatial placement, color, and texture properties into a visualization algorithm. This algorithm represents important aspects of a purchase order based on experimental results from human vision, computer graphics, and psychology. The resulting visual abstractions are used by viewers to rapidly and effectively explore and analyze the underlying purchase orders data.
By Amit Prakash Sawant, Christopher G. Healey, Dongfeng Chen, Rada Chirkova, March 2009
Modding
By Caio Camargo, March 2009
Detecting steganography on a large scale
By William Ella, December 2008
Exploring global terrorism data
By Joonghoon Lee, December 2008
Digital blasphemy
By Cara Cocking, December 2008
Towards a user-friendly semantic formalism for natural language generation
Computational semantics has become an interesting and important branch of computational linguistics. Born from the fusion of formal semantics and computer science, it is concerned with the automated processing of meaning associated with natural language expressions [2]. Systems of semantic representation, hereafter referred to as semantic formalisms, exist to describe meaning underlying natural language expressions. To date, several formalisms have been defined by researchers from a number of diverse disciplines including philosophy, logic, psychology and linguistics. These formalisms have a number of different applications in the realm of computer science. For example, in machine translation a sentence could be parsed and translated into a series of semantic expressions, which could then be used to generate an utterance with the same meaning in a different language [14]. This paper presents two existing formalisms and examines their user-friendliness. Additionally, a new form of semantic representation is proposed with wide coverage and user-friendliness suitable for a computational linguist.
By Craig Thomas, December 2008
Motion planning for skateboard-like robots in dynamic environments
By Salik Syed, September 2008
The use of compiler optimizations for embedded systems software
Optimizing embedded applications using a compiler can generally be broken down into two major categories: hand-optimizing code to take advantage of a particular processor's compiler and applying built-in optimization options to proven and well-polished code. The former is well documented for different processors, but little has been done to find generalized methods for optimal sets of compiler options based on common goal criteria such as application code size, execution speed, power consumption, and build time. This article discusses the fundamental differences between these two general categories of optimizations using the compiler. Examples of common, built-in compiler options are presented using a simulated ARM processor and C compiler, along with a simple methodology that can be applied to any embedded compiler for finding an optimal set of compiler options.
By Joe Bungo, September 2008
Geometric and path tracing methods for simulating light transport through volumes of water particles
The visual appearance of volumes of water particles, such as clouds, waterfalls, and fog, depends both on microscopic interactions between light rays and individual droplets of water, and also on macroscopic interactions between multiple droplets and paths of light rays. This paper presents a model that builds upon a typical single-scattering volume renderer to correctly account for these effects. To accurately simulate the visual appearance of a surface or a volume of particles in a computer-generated image, the properties of the material or particle must be specified using a Bidirectional Reflectance Distribution Function (BRDF), which describes how light reflects off of a material, and the Bidirectional Transmittance Distribution Function (BTDF), which describes how light refracts into a material. This paper describes an optimized BRDF and BTDF for volumes of water droplets, which takes their geometry into account in order to produce well-known effects, such as rainbows and halos. It also describes how a multiple-scattering path tracing volume integrator can be used to more accurately simulate macroscopic light transport through a volume of water, creating a more "cloudlike" appearance than a single-scattered volume integrator. This paper focuses on replicating the visual appearance of volumes of water particles, and although it makes use of physical models, the techniques presented are not intended to be physically accurate.
By James Hegarty, September 2008
Data encryption
By Ed DeHart, September 2008
Mixed nuts
By Sid Stamm, June 2008
MultiVizArch
This article presents an automated technique for visualizing large software architectures using multiple graphical representations, including multi-dimensional scaling, 2-D grid, and spiral layouts. We describe how our software visualization methods were applied to the Network Appliance operating system known as Data ONTAP 7G (ONTAP). We show how each method can be applied to comprehend a specific aspect of ONTAP. This approach can be used by software engineers, architects, and developers to better understand the architecture of their code.
By Amit Prakash Sawant, Naveen Bali, March 2008
Finding an optimal tooth color match
By Cara Cocking, March 2008
Technical writing 101
By Leslie Sandoval, March 2008
Planning and improvisation in software processes
This paper presents the results of an empirical study aimed at examining the extent to which software engineers follow a software process and the extent to which they improvise during the process. Our subjects tended to classify processes into two groups. In the first group are the processes that are formal, strict, and well-documented. In the second group are the processes that are informal and not well-structured. The classification has similar characteristics to the model proposed by Truex, Baskerville, and Travis [12]. Our first group is similar to their methodical classification, and our second group is similar to their amethodical classification. Interestingly, software engineers using a process in the second group stated that they were not using a process. We believe that software engineers who think that they are not using a process, because they have the prevalent concept of process as something methodical that is strict and structured, actually are using an informal (amethodical) process. We also found that software engineers improvise while using both types of processes in order to overcome shortcomings in the planned path which arose due to unexpected situations. This finding leads us to conclude that amethodical processes are processes too.
By Rosalva E. Gallardo-Valencia, Susan Elliott Sim, December 2007
Visualizing flow data using assorted glyphs
This project visualizes a scientific dataset containing two-dimensional flow data from a simulated supernova collapse provided by astrophysics researchers. We started our project by designing visualizations using multiple hand drawings representing the flow data without taking into consideration the implementation constraints of our designs. We implemented a few of our hand drawn designs. We used an assortment of simple geometric graphical objects, called glyphs, such as, dots, lines, arrows, and triangles to represent the flow at each sample point. We also incorporated transparency in our visualizations. We identified two important goals for our project: (1) design different types of graphical glyphs to support flexibility in their placement and in their ability to represent multidimensional data elements, and (2) build an effective visualization technique that uses glyphs to represent the two-dimensional flow field.
By Amit Prakash Sawant, Christopher G. Healey, December 2007
Trends in real-time rendering
Fans of PC role-playing games need no introduction to Bioware-the Edmonton, Alberta based developer of Baldur's Gate, Neverwinter Nights, and Jade Empire, among others. The company recently opened a studio in Austin, Texas to develop a massively multiplayer online role-playing game (MMORPG, or simply MMO) for an unannounced intellectual property. Ben Earhart, client technology lead on the new project, took a few hours out of his busy schedule to discuss with Crossroads the future of real-time rendering-3-D graphics that render fast enough to respond to user input, such as those required for video games.
By James Stewart, December 2007
An approach for detecting prosodic phrase boundaries in spoken english
Prosodic phrasing is the means by which speakers of any given language break up an utterance into meaningful chunks. The term "prosody" itself refers to the tune or intonation of an utterance, and therefore prosodic phrases literally signal the end of one tune and the beginning of another. This study uses phrase break annotations in the Aix-MARSEC corpus of spoken English as a "gold standard" for measuring the degree of correspondence between prosodic phrases and the discrete syntactic grouping of prepositional phrases, where the latter is defined via a chunk parsing rule using nltk_lite's regular expression chunk parser.
A three-way comparison is also introduced between the "gold standard" chunk parsing rule and human judgment in the form of intuitive predictions about phrasing. Results show that even with a discrete syntactic grouping and a small sample of text, problems may arise for this rule-based method due to uncategorical behavior in parts of speech. Lack of correspondence between intuitive prosodic phrases and corpus annotations highlights the optional nature of certain boundary types. Finally, there are clear indications, supported by corpus annotations, that significant prosodic phrase boundaries occur within sentences and not just at full stops.
By Claire Brierley, Eric Atwell, December 2007
On the complexity of Katamari Damacy
By Gregory M. Zaverucha, December 2007
Hearing the Hype
By Daniel Alex Finkelstein, December 2007
Adaptively ranking alerts generated from automated static analysis
Static analysis tools are useful for finding common programming mistakes that often lead to field failures. However, static analysis tools regularly generate a high number of false positive alerts, requiring manual inspection by the developer to determine if an alert is an indication of a fault. The adaptive ranking model presented in this paper utilizes feedback from developers about inspected alerts in order to rank the remaining alerts by the likelihood that an alert is an indication of a fault. Alerts are ranked based on the homogeneity of populations of generated alerts, historical developer feedback in the form of suppressing false positives and fixing true positive alerts, and historical, application-specific data about the alert ranking factors. The ordering of alerts generated by the adaptive ranking model is compared to a baseline of randomly-, optimally-, and static analysis tool-ordered alerts in a small role-based health care application. The adaptive ranking model provides developers with 81% of true positive alerts after investigating only 20% of the alerts whereas an average of 50 random orderings of the same alerts found only 22% of true positive alerts after investigating 20% of the generated alerts.
By Sarah Smith Heckman, December 2007
Storage capacity comparison of neural network models for memory recall
The physiology of how the human brain recalls memories is not well understood. Neural networks have been used in an attempt to model this process.
Two types of networks have been used in several models of temporal sequence memory for simple sequences of randomly generated and also of structured patterns: auto- and hetero-associative networks. Previous work has shown that a model with coupled auto- and hetero-associative continuous attractor networks can robustly recall learned simple sequences. In this paper, we compare Hebbian learning and pseudo-inverse learning in a model for recalling temporal sequences in terms of their storage capacities. The pseudo-inverse learning method is shown to have a much higher storage capacity, making the new network model 700% more efficient by reducing calculations.
By Kate Patterson, December 2007
Getting started on natural language processing with Python
By Nitin Madnani, September 2007
Use of motion field warping to generate cardiac images
In this study, we developed an algorithmic method to analyze late contrast-enhanced (CE) magnetic resonance (MR) images, revealing the so-called hibernating myocardium. The algorithm is based on an efficient and robust image registration algorithm. Using our method, we are able to integrate the static late CE MR image with its corresponding cardiac cine MR images, constructing cardiac motion CE MR images, which are referred to as cardiac cine CE MR images. This method appears promising as an improved cardiac viability assessment tool
By Gang Gao, Paul Cockshott, September 2007
Voice activity detection
By Deepti Singh, Frank Boland, September 2007
Modeling object states and behaviors using a state action manager
This design pattern is an extension of the well-known state pattern [2], which allows an object to change its behavior depending on the internal state of the object. The behavior is defined by events, whose transformation to actions depends on the object state. This pattern introduces a way to manage state actions.
By Gunther Palfinger, September 2007
Computational recreations
By Jonathan Doyle, September 2007
The science of shape
By Justin Solomon, September 2007
Avoid common pitfalls when programming 2D graphics in java
This paper presents the core knowledge required to properly develop 2D games in Java. We describe the common pitfalls that can easily degrade graphics performance and show how we achieved impressive frames-per-second display updates when implementing Minueto, a game development framework.
By Alexandre Denault, Jörg Kienzle, March 2007
Prostate ultrasound image processing
By Deian Stefan, March 2007
Interesting complexity
By Caio Camargo, December 2006
Achieving I/O improvements in a mass spectral database
Research in proteomics has created two significant needs: the need for an accurate public database of empirically derived mass spectrum information and the need for managing the I/O and organization of mass spectrometry data in the form of files and structures. Lack of an empirically derived database limits the ability of proteomic researchers to identify and study proteins. Managing the I/O and organization of mass spectrometry data is often time-consuming due to the many fields that need to be set and retrieved. As a result, incompatibilities and inefficiencies are created by each programmer handling this in his or her own way. Until recently, storage space and computing power has been the limiting factor in developing tools to handle the vast amount of mass spectrometry information. Now the resources are available to store, organize, and analyze mass spectrometry information.The Illinois Bio-Grid Mass Spectrometry Database is a database of empirically derived tandem mass spectra of peptides created to provide researchers with an organized and searchable database of curated spectrum information to allow more accurate protein identification. The Mass Spectrometry I/O Project creates a framework that handles mass spectrometry data I/O and data organization, allowing researchers to concentrate on data analysis rather than I/O. In addition, the Mass Spectrometry I/O Project leverages several cross-platform and portability-enhancing technologies, allowing it to be utilized on a variety of hardware and operating systems.
By Eric Puryear, Jennifer Van Puymbrouck, David Sigfredo Angulo, Kevin Drew, Lee Ann Hollenbeck, Dominic Battre, Alex Schilling, David Jabon, Gregor von Laszewski, December 2006
Ultimate car entertainment systems
By Nick Datzov, December 2006
Modeling protein dependency networks using CoCoA
In an interdisciplinary effort to model protein dependency networks, biologists measure signals from certain proteins within cells over a given interval of time. Using this time series data, the goal is to deduce protein dependency relationships. The mathematical challenges is to statistically measure correlations between given proteins over time in order to conjecture probable relationships. Biologists can then consider these relationships with more scrutiny, in order to confirm their conjectures. One algorithm for finding such relationships makes use of interpolation of the data to produce next-state functions for each protein and the Deegan-Packel Index of Power voting method to measure the strength of correlations between pairs of proteins. The algorithm was previously implemented, but limitations associated with the original language required the algorithm to be re-implemented in a more computationally efficient language. Because of the algebraic focus of the Computational Commutative Algebra language, or CoCoA, the algorithm was re-implemented in this language, and results have been produced much more efficiently. In this paper I discuss the algorithm, the CoCoA language, the implementation of the algorithm in CoCoA, and the quality of the results.
By Grey Ballard, September 2006
Becoming a virtual organism to learn about genetics
By Alexander Bick, September 2006
Aligning DNA sequences using dynamic programming
By Eric C. Rouchka, September 2006
TigerEvents
By Chris Jordan, Oliver Baltzer, Sean Smith, August 2006
RAS
By Jarrod Trevathan, Wayne Read, August 2006
Architecting trust-enabled peer-to-peer file-sharing applications
Decentralized peer-to-peer (P2P) resource sharing applications lack a centralized authority that can facilitate peer and resource look-ups and coordinate resource sharing between peers. Instead, peers directly interact and exchange resources with other peers. These systems are often open and do not regulate the entry of peers into the system. Thus, there can be malicious peers in the system who threaten others by offering Trojan horses and viruses disguised as seemingly innocent resources. Several trust-based solutions exist to address such threats; unfortunately there is a lack of design guidance on how these solutions can be integrated into a resource sharing application. In this paper, we describe how two teams of undergraduate students separately integrated XREP, a third-party reputation-based protocol for file-sharing applications, with PACE, our software architecture-based approach for decentralized trust management. This was done in order to construct trust-enabled P2P file-sharing application prototypes. Our observations have revealed that using an architecture-based approach in incorporating trust into P2P resource-sharing applications is not only feasible, but also significantly beneficial. Our efforts also demonstrate both the ease of adoption and ease of use of the PACE-based approach in constructing such trust-enabled decentralized applications.
By Girish Suryanarayana, Mamadou H. Diallo, Justin R. Erenkrantz, Richard N. Taylor, August 2006
Architecture-centric development
By John C. Georgas, Eric M. Dashofy, Richard N. Taylor, August 2006
C-Transformers
By Alexandre Borghi, Valentin David, Akim Demaille, May 2006
Stratego
Programming languages have a dual role in the construction of software. The language is both our substrate (the stuff we make software from), and our tool (what we use to construct software). Program transformation (PT) deals with the analysis, manipulation and generation of software. Therefore a close relationship exists between program transformation and programming languages, to the point where the PT field has produced many domain-specific languages for manipulating programs. In this article, I will show you some interesting aspects from one of these languages : Stratego.
By Karl Trygve Kalleberg, May 2006
A crash overview of groovy
By Kevin Henry, May 2006
Microsoft windows programming strategies
By Mike Maxim, May 2006
Challenges in HCI
By Kibum Kim, December 2005
HCI Applications for aiding children with mental disorders
By Hossein Mobahi, Karrie G. Karahalios, December 2005
When news is more than what makes headlines
By Kayre Hylton, Mary Beth Rosson, John Carroll, Craig Ganoe, December 2005
Comparison of input devices and displays for protein visualization
By Elke Moritz, Thomas Wischgoll, Joerg Meyer, December 2005
Eureka! past, present, and future of creativity research in HCI
By Umer Farooq, December 2005
Introduction to programming shared-memory and distributed-memory parallel computers
By Cory Quammen, October 2005
Game-state fidelity across distributed interactive games
By Aaron McCoy, Declan Delaney, Tomas Ward, October 2005
Using software watermarking to discourage piracy
By Ginger Myles, October 2005
The development of a game playing framework using interface-based programming
By Mark A. Cohen, October 2005
Using perception in managing unstructured documents
By Ching Kang Cheng, Xiaoshan Pan, October 2005
Learning from nature
By Anh Nguyen, Tadashi Nakano, Tatsuya Suda, August 2005
An interaction model for mobile agent services using social networks
By Vishakh, Nicholas Urrea, Tadashi Nakano, Tatsuya Suda, August 2005
Introduction to automatic design of wireless networks
By K. E. Oliver, August 2005
Overcoming misbehavior in mobile ad hoc networks
By George Athanasiou, Leandros Tassiulas, Gregory S. Yovanof, August 2005
Experimental mobile gateways
By Premshree Pillai, August 2005
Security, anonymity and trust in electronic auctions
By Jarrod Trevathan, May 2005
An introduction to quantum cryptography
By Nick Papanikolaou, May 2005
An introduction to side channel cryptanalysis of RSA
By Artemios G. Voyiatzis, May 2005
Timing attacks on RSA
By Wing H. Wong, May 2005
Obfuscation of the standard XOR Encryption algorithm
By Zachary A. Kissel, May 2005
Learning how to tell ham from spam
By George Sakkis, December 2004
Identifying spam without peeking at the contents
By Shlomo Hershkop, Salvatore J. Stolfo, December 2004
Peer-to-peer collaborative spam detection
By Nathan Dimmock, Ian Maddison, December 2004
The humanoid Robot Cog
By Naveed Ahmad, December 2003
Using perception in managing unstructured documents
By Ching Kang Cheng, Xiaoshan Pan, December 2003
E-commerce recommenders
By Ana Gil, Francisco García, December 2003
Zero configuration networking
By David Stirling, Firas Al-Ali, June 2003
The application of artificial intelligence to transportation system design
By Ricardo Hoar, Joanne Penner, March 2003
Simulation of a computer architecture for quantum chromodynamics calculations
By Sadaf Alam, Roland Ibbett, Frederic Mallet, March 2003
Automatic generation of French speech
By Craig Thomas, March 2003
Building a nocturnal cluster with nonstandard hardware
By Eric J. Shamow, December 2002
Q2ADPZ* an open source, multi-platform system for distributed computing
By Zoran Constantinescu, Pavel Petrovic, December 2002
ART - the abstract robot toolkit
By Stephan Jätzold, August 2002
Building an MPI cluster
By Donald C. Bergen, Boise P. Miller, August 2002
Optimizing application performance
By M. Tyler Maxwell, Kirk W. Cameron, August 2002
Desktop open source
By Bryan Stroube, June 2002
Technologies for the development of agent-based distributed applications
By Tobias Butte, April 2002
Introduction to programming shared-memory and distributed-memory parallel computers
By Cory Quammen, April 2002
An introduction to Java servlet programming
By Vandana Pursnani, December 2001
Hungry robots
By Tony Belpaeme, Andreas Birk, December 2001
Tools tutorials, part deux
By Bill Stevenson, July 2001
Connector
By Kostas Pentikousis, July 2001
Why bison is becoming extinct
At some point in your career, you're going to implement a computer language. You probably won't be implementing Java or C++. You may not even recognize it as a language. Truth be told, there are an awful lot of domain-specific languages, or "little languages" [7] in common use:
- configuration files,
- HTML/XML documents,
- shell scripts,
- network protocols,
- mail headers,
- command-line arguments.
By John Aycock, July 2001
Common mistakes in online and real-time contests
Each year the Association for Computing Machinery (ACM) arranges a worldwide programming contest. This contest has two rounds: the regional contests and the World Final. The teams with the best results in the regional contests advance to the World Final. The contest showcases the best programmers in the world to representatives of large companies who are looking for talent. When practicing for programming competitions, remember that all your efforts should be directed at improving your programming skills. No matter what your performance is in a contest, don't be disappointed. Success in programming contests is affected by factors other than skill, most importantly, adrenaline, luck, and the problem set of the contest. One way of getting immediate feedback on your efforts is to join the Valladolid Online Programming Practice/Contest or the online judge hosted by Ural State University (USU). Successfully solving problems increases your online ranking in the respective competitions.This article is for beginning programmers who are new to programming contests. I will discuss the common problems faced in contests, the University of Valladolid online judge, and the USU online judge. The suggestions are divided into three parts: General Suggestions, Online Contest Suggestions, and Valladolid-Specific Suggestions. Throughout this paper, please note that in real-time contests, the judges are human and in online contests, the judges are computer programs, unless otherwise noted.
By Shahriar Manzoor, July 2001
Using apache as a caching proxy server
By Josiah Dykstra, July 2001
Objects objects everywhere
By Todd M. Manion, March 2001
Object-relational database systems — the road ahead
By Ramakanth Subrahmanya Devarakonda, March 2001
Extracting semantic metadata and its visualization
By Dongwon Lee, Yousub Hwang, March 2001
Introduction to mobile computing
By Sandeep Jain, December 2000
Cellular networks
By Lourens O. Walters, P. S. Kritzinger, December 2000
Designing an e-commerce site for users
By Norbert J. Kubilus, September 2000
Electronic commerce universal access device-the knowledge-acquiring layered infrastructure (KALI) project
By Theodore Chiasson, Carrie Gates, September 2000
Objective ViewPoint: distributed computation with Java remote method invocation
By Kevin Henry, July 2000
Macromedia director as a prototyping and usability testing tool
By Stephanie Ludi, July 2000
Objective viewpoint: make your GUI swing
By Matt Tucker, June 2000
Charlotte
By Stuart Patterson, June 2000
Graphic libraries for Windows programming
By M. Carmen Juan Lizandra, June 2000
Microsoft Windows programming strategies
By Mike Maxim, June 2000
The many dimensions of the software process
By Sebastián Tyrrell, June 2000
A bibliography manager for Microsoft Word
By José H. Canós, June 2000
The world of data compression
By Eric Scheirer, March 2000
In memory of David Huffman
By Kevin Fu, March 2000
Objective viewpoint
By Matt Tucker, March 2000
Design of an interactive tutorial for logic and logical circuits
By Jeremy Kindy, John Shuping, Patricia Yali Underhill, David John, March 2000
Image compression—from DCT to wavelets
By Subhasis Saha, March 2000
Prefix compression of sparse binary strings
Note from ACM Crossroads: Due to errors in the layout process for printing on paper, the version of this article in the printed magazine contained several errors (mostly related to superscripts). This HTML version is the accurate version. Please refer to this HTML version instead of the printed version and accept our apologies for any inconvenience.
By David Salomon, March 2000
A hierarchical error controlled octree data structure for large-scale visualization
By Dmitriy V. Pinskiy, Joerg Meyer, Bernd Hamann, Kenneth I. Joy, Eric Brugger, Mark Duchaineau, March 2000
Ask Jack
By Jack Wilson, March 2000
RTLinux
By Kevin Fu, September 1999
Introduction
By Kevin Fu, September 1999
Objective viewpoint
By George Crawford, September 1999
Choosing a Ph.D. program in computer science
By Rachel Pottinger, September 1999
Linux DSP shell
By Michael Stricklen, Bob Cummings, Brandon Bonner, September 1999
Introduction to Linux networking and security
By Wei-Mei Shyr, Brian Borowski, September 1999
Parallel computing with Linux
By Forrest Hoffman, William Hargrove, September 1999
The Texas Tech tornado cluster
By Per Andersen, September 1999
Introduction
By Alessio Lomusico, June 1999
Books reviews
By Lynellen D. S. Perry, Erika Orrick, June 1999
Where do intelligent agents come from?
By Cristobal Baray, Kyle Wagner, June 1999
Protecting the integrity of agents
By Michael J. Grimley, Brian D. Monroe, June 1999
Towards a standardization of multi-agent system framework
By Roberto A. Flores-Mendez, June 1999
Web hunting
By G. Michael Youngblood, June 1999
Re-configurable computing
By Richard Swan, Anthony Wyatt, Richard Cant, Caroline Langensiepen, April 1999
The processor-memory bottleneck
The rate of improvement in microprocessor speed exceeds the rate of improvement in DRAM (Dynamic Random Access Memory) speed. So although the disparity between processor and memory speed is already an issue, downstream someplace it will be a much bigger one. Hence computer designers are faced with an increasing Processor - Memory Performance Gap [1], which now is the primary obstacle to improved computer system performance. This article examines this problem as well as its various solutions.
By Nihar R. Mahapatra, Balakrishna Venkatrao, April 1999
Introduction
By Scott Lewandowski, March 1999
Objective viewpoint
By George Crawford, March 1999
Making a careers presentation
By Jack Wilson, March 1999
PiSMA
By Dimitris Lioupis, Andreas Pipis, Maria Smirli, Michael Stefanidakis, March 1999
Architectures and compilers to support reconfigurable computing
By João M. P. Cardoso, Mário P. Vestístias, March 1999
Computing in the former Soviet Union and eastern Europe
By Shane Hart, March 1999
Parallel processing in heterogeneous cluster architechtures using JavaPorts
By Demetris G. Galatopoullos, Elias S. Manolakos, March 1999
Networks and distributed systems: introduction
By Kevin Fu, November 1998
Web site review: ADSL forum
By Shawn Brown, November 1998
Creating a 3D universe in Java3D
By George Crawford, November 1998
Ask Jack: making a careers presentation
By Jack Wilson, November 1998
AgentOS
By Larry Chen, November 1998
Design and implementation of a digital library
By James Richvalsky, David Watkins, November 1998
Confidentially using authentication
By Robert Schlaff, November 1998
Knowledge discovery in databases
By Peggy Wright, November 1998
The Damocles Sword of Academic Publishing
Doctoral students often find it hard to understand at what level of productivity they should be. Through an analysis of resums of doctoral students in the Management Information Systems (MIS) field, a better understanding of what is expected of current students as compared to former students is achieved. Both conference presentations and publications in journals are examined. Finally, there is an examination of whether the quantity of publications can be related to the ranking of the school that a student attends.
By Kai Larsen, November 1998
Introduction
By Lynellen D. S. Perry, September 1998
Web site review: the Ada project
By Lynellen D. S. Perry, September 1998
Objective viewpoint: Java AWT layout management 101
This article provides a brief summary of basic layout management in the Java Abstract Window Toolkit (AWT) and is intended to serve as a foundation for more sophisticated AWT programming.
By George Crawford, September 1998
Ask Jack: careerline Q & A
By Jack Wilson, September 1998
A formative evaluation of scenario-based tools for learning object-oriented design
Advances in computing have awakened a century old teaching philosophy: learner-centered education. This philosophy is founded on the premise that people learn best when engrossed in the topic, participating in activities that motivate learning and help them to synthesize their own understanding. We consider how the object-oriented design (OOD) learning tools developed by Rosson and Carroll [5] facilitate active learning of this sort. We observed sixteen students as they worked through a set of user interaction scenarios about a blackjack game. We discuss how the features of these learning tools influenced the students' efforts to learn the basic constructs of OOD.
By Hope D. Harley, Cheryl D. Seals, Mary Beth Rosson, September 1998
Much ado about patterns
By Robert Zubek, September 1998
Explanation component of software system
Explanation is an important feature that needs to be integrated into software products. Early software that filled the horizontal software market (such as word processors) contained help systems. More specialized systems, known as expert systems, were developed to produce solutions that required specific domain knowledge of the problem being solved. The expert systems initially produced results that were consistent with the results produced by experts, but the expert systems only mimicked the rules the experts outlined. The decisions provided by expert systems include no justification, thus causing users to doubt the results reported by the system. If the user was dealing with a human expert, he could ask for a line of reasoning used to draw the conclusion. The line of reasoning provided by the human expert could then be inspected for discrepancies by another expert or verified in some other manner. Software systems need better explanations of how to use them and how they produce results. This will allow the users to take advantage of the numerous features being provided and increase their trust in the software product.
By Bruce A. Wooley, September 1998
Multimedia systems: introduction
By Erika Dawn Gernand, May 1998
Towards usability evaluation of multimedia applications
By Marianne G. Petersen, May 1998
The use of Java as an introductory programming language
By Jason Hong, May 1998
Networking on the network
By Phil Agre, May 1998
The Turing test
By Lynellen D. S. Perry, May 1998
A simple SMTP framework for Java
By George Crawford, May 1998
Ask Jack: job search in cyberspace
By Jack Wilson, May 1998
Robotics
By Randolph Chung, Lynellen D. S. Perry, April 1998
Mars rover
By Sharon Lauback, April 1998
RoboCup
By Hiroaki Kitano, Minoru Asada, Itsuki Noda, Hitoshi Matsubara, April 1998
CMUnited
Robotic soccer is a challenging research domain involving multiple agents that need to collaborate in an adversarial environment to achieve specific objectives. This article describes CMUnited, the team of small robotic agents that we developed to enter the RoboCup-97 competition. We designed and built the robotic agents, devised the appropriate vision algorithm, and developed and implemented algorithms for strategic collaboration between the robots in an uncertain and dynamic environment. The robots can organize themselves in formations, hold specific roles, and pursue their goals. In game situations, they have demonstrated their collaborative behaviors on multiple occasions. The robots can also switch roles to maximize the overall performance of the team. We present an overview of the vision processing algorithm which successfully tracks multiple moving objects and predicts trajectories. The paper then focuses on the agents' behaviors ranging from low-level individual behaviors to coordinated, strategic team behaviors. CMUnited won the RoboCup-97 small-robot competition at IJCAI-97 in Nagoya, Japan.
By Manuela Veloso, Peter Stone, Kwun Han, Sorin Achim, April 1998
Evolutionary control via sensorimotor input and actuation
By Todd M. Schrider, April 1998
Protecting Java code via code obfuscation
The Java language is compiled into a platform independent bytecode format. Much of the information contained in the original source code remains in the bytecode, thus decompilation is easy. We will examine how code obfuscation can help protect Java bytecodes.
By Douglas Low, April 1998
A practical crash course in Java 1.1+ programming and technology: part II
By George Crawford, April 1998
Ask Jack: Internet career
By Jack Wilson, April 1998
Book Review
By Lynellen D. S. Perry, April 1998
Road crew
By John Cavazos, April 1998
Java:introduction
By Vishal Shah, November 1997
The wonders of Java object serialization
By Brian T. Kurotsuchi, November 1997
Using the Java Native Interface
The Java Native Interface (JNI) comes with the standard Java Development Kit (JDK) from Sun Microsystems. It permits Java programmers to integrate native code (currently C and C++) into their Java applications. This article will focus on how to make use of the JNI and will provide a few examples illustrating the usefulness of this feature. Although a native method system was included with the JDK 1.0 release, this article is concerned with the JDK 1.1 JNI which has several new features, and is much cleaner than the previous release. Also, the examples given will be specific to JDK 1.1 installed on the Solaris Operating System.
By S. Fouzi Husaini, November 1997
A practical crash course in Java 1.1+ programming and technology: part I
By George Crawford, November 1997
Road crew
By John Cavazos, November 1997
Interdisiplinary computer science: introduction
By Michael A. Grasso, Mark R. Nelson, October 1997
Geographic information systems and problem solving environments
By Jinsoo Park, October 1997
A sustainable fishing simulation using mathematical modeling and database access through the World Wide Web
By Vineet Kapur, Douglas Troy, James Oris, October 1997
Mapping and sequencing the human genome
By Wayne Smith, October 1997
Foundations of electronic commerce
By Neal G. Shaw, October 1997
Everything's coming up virtual
By Susan E. Yager, October 1997
St. Cloud State University ACM chapter wins 2nd annual Webbie prize
By Hal Berghel, October 1997
Ask Jack: skill development
By Jack Wilson, October 1997
Down the road: is something missing from your campus?
By Thomas C. Waszak, October 1997
Road crew
By John Cavazos, October 1997
Computer graphics: introduction
By Adam Lake, May 1997
Ray tracing
By Paul Rademacher, May 1997
A human's eye view
Frameless Rendering (FR) is a rendering paradigm which performs stochastic temporal filtering by updating pixels in a random order, based on most recent available input data, and displaying them to the screen immediately [1]. This is a departure from frame-based approaches commonly experienced in interactive graphics. A typical interactive graphics session uses a single input state to compute an entire frame. This constrains the state to be known at the time the first pixel's value is computed. Frameless Rendering samples inputs many times during the interval which begins at the start of the first pixel's computation and ends with the last pixel's computation. Thus, Frameless Rendering performs temporal supersampling - it uses more samples over time. This results in an approximation to motion blur, both theoretically and perceptually.This paper explores this motion blur and its relationship to: camera open shutter time, current computer graphics motion-blur implementations, temporally anti-aliased images, and the Human Visual System's (HVS) motion smear quality (see 'quality' footnote) [2].Finally, we integrate existing research results to conjecture how Frameless Rendering can use knowledge of the Human Visual System's blurred retinal image to direct spatiotemporal sampling. In other words, we suggest importance sampling (see 'sampling' footnote) by prioritizing pixels for computation based on their importance to the visual system in discerning what is occurring in an interactive image sequence.
By Ellen J. Scher Zagier, May 1997
Levels of detail & polygonal simplification
This paper covers the techniques of Polygonal Simplification in order to produce Levels of Detail (LODs). The problem of creating LODs is a complex one: how can simpler versions of a model be created? How can the approximation error be measured? How can the visual degradation be estimated? Can all this be done automatically? After exposing the basic aims and principles of polygonal simplification, we compare recent algorithms and state their various qualities and weaknesses.
By Mike Krus, Patrick Bourdot, Françoise Guisnel, Gullaume Thibault, May 1997
Faster 3D game graphics by not drawing what is not seen
The increasing demands of 3D game realism - in terms of both scene complexity and speed of animation - are placing excessive strain on the current low-level, computationally expensive graphics drawing operations. Despite these routines being highly optimized, specialized, and often being implemented in assembly language or even in hardware, the ever-increasing number of drawing requests for a single frame of animation causes even these systems to become overloaded, degrading the overall performance. To offset these demands and dramatically reduce the load on the graphics subsystem, we present a system that quickly and efficiently finds a large portion of the game world that is not visible to the viewer for each frame of animation, and simply prevents it from being sent to the graphics system. We build this searching mechanism for unseen parts from common and easily implemented graphics algorithms.
By Kenneth E. Hoff, May 1997
Advice for undergraduates considering graduate school
By Phil Agre, May 1997
An introduction to the GIMP
By Matt Cutts, May 1997
Ask Jack: skill development
By Jack Wilson, May 1997
Road crew
By John Cavazos, May 1997
Human computer interaction: introduction
By Sofia C. DeFernandez, April 1997
Techniques & tools for using color in computer interface design
Contemporary computers predominantly employ graphical user interfaces (GUIS) and colour is a major componenet of the GUI. Every man-machine interface is composed of two major parts:the man and the machine [4]. Color interfaces are no different in that they are also based on two parts, the Human visual system (HVS) and a color display system. A theoretical examination of these two components establishes a foundation for developing practical guidelines for color interfaces. This paper will briefly examine theoretical aspects of both components and established techniques and tools for the effective use of color for software interface design.
By Peggy Wright, Diane Mosser-Wooley, Bruce Wooley, April 1997
User interface correctness
By Ian MacColl, David Carrington, April 1997
Human factors in haptic interfaces
By Christopher M. Smith, April 1997
Task integration in multimodal speech recognition environments
By Michael A. Grasso, Tim Finin, April 1997
An investigation of current virtual reality interfaces
Virtual Reality hype is becoming a large part of everyday life. This paper explores the components of actual virtual reality systems, critiquing each in terms of human factors. The hardware and software of visual, aural, and haptic input and feedback are considered. Technical and human factor difficulties are discussed and some potential solutions are offered.
By Lynellen D. S. Perry, Christopher M. Smith, Steven Yang, April 1997
Ask Jack: negotiating
By Jack Wilson, April 1997
Computer games: introduction
By John Cavazos, November 1996
The story of XPilot
By Bjorn Stabell, Ken Ronny Schouten, November 1996
The video game [R]evolution
By Sarah Elizabeth Burcham, November 1996
Computer game marketing bias
By Melissa Chaika, November 1996
Research posters 101
By Lorrie Faith Cranor, November 1996
Programming contest strategies
By Fabian Ernst, Jeroen Moelands, Seppo Pieterse, November 1996
Objective view point: a cornucopia of C++ resources
By G. Bowden Wise, November 1996
Ask Jack: summer jobs and job skills
By Jack Wilson, November 1996
Down the road: getting women involved
By Sara Carlstead, November 1996
Book Reviews: game programming
By Lynellen D. S. Perry, November 1996
Road crew
By John Cavazos, November 1996
Artificial intelligence: introduction
By Frank Klassner, September 1996
An interview with Drew McDermott
By Kentaro Toyama, Drew McDermott, September 1996
Emotionware
By Lynellen D. S. Perry, September 1996
Computer vision and artificial intelligence
By Christopher O. Jaynes, September 1996
Applications of AI in education
By Joseph Beck, Mia Stern, Erik Haugsjaa, September 1996
Reasoning about computational resource allocation
Anytime Algorithms are algorithms that exchange execution time for quality of results. Since many computational tasks are too complicated to be completed at real-time speeds, anytime algorithms allow systems to intelligently allocate computational time resources in the most effective way, depending on the current environment and the system's goals. This article briefly covers the motivations for creating anytime algorithms, the history of their development, a definition of anytime algorithms, and current research involving anytime algorithms.
By Joshua Grass, September 1996
Objective view point: casting in C++
By G. Bowden Wise, September 1996
Ask Jack: finding a job
By Jack Wilson, September 1996
Book review:Bandits on the information Superhighway
By Paul Rubel, September 1996
Road crew
By Lorrie Faith Cranor, September 1996
Computer security past and future
By Michael Neuman, Diana Moore, April 1996
An introduction to intrusion detection
By Aurobindo Sundaram, April 1996
Trust mechanisms for Hummingbird
By Jason Evans, Deborah Frincke, April 1996
Electronic voting
By Lorrie Faith Cranor, April 1996
Mutual authenticating protocol with key distribution in client/server environment
The explosive growth of networked and internetworked computer systems during the past decade has brought about a need for increased protection mechanisms. This paper discusses three authentication protocols that incorporate the use of methods that present effective user authentication. The first two protocols have been previously discussed in the literature; the third protocol draws from the first two and others to produce an authentication scheme that provides both mutual authentication and secure key distribution which is easy to use, is compatible with present operating systems, is transparent across systems, and provides password file protection.
By Charles Cavaiani, Jim Alves-Foss, April 1996
Objective View Point: statics
By G. Bowden Wise, April 1996
Ask Jack: negotiating with companies
By Jack Wilson, April 1996
Road crew
By Lorrie Faith Cranor, April 1996
An interview with Brad Templeton
By George E. Hatoun, Brad Templeton, February 1996
Software engineering
By Dan Ghica, February 1996
It's now or never
By C. Fidge, February 1996
Dependency diagrams
A method of illustrating program structure by showing how sections depend on each other is presented. This suggests an intuitive metric for program partitioning, which is developed with supporting theory.
By Mark Ray, February 1996
Facilitating abstraction and reuse with ExpectTK
By Navid Sabbaghi, February 1996
Objective View Point: an overview of the Standard Template Library
By G. Bowden Wise, February 1996
The road less traveled: Internet collaboration
By Lorrie Faith Cranor, February 1996
Software review: to warp or not to warp
By Scott Ramsay MacDonald, February 1996
Ask Jack: resume should reflect real you
By Jack Wilson, February 1996
Down the Road: University of Pennsylvania
By Sara M. Carlstead, February 1996
Road crew
By Lorrie Faith Cranor, February 1996
The Road Less Traveled: it shouldn't be allowed!
By Lorrie Faith Cranor, November 1995
Computer-based decision-making
By Jeff Robbins, November 1995
Copyright law meets the World Wide Web
By Matt Rosenberg, November 1995
Ethical considerations in gender-oriented entertainment technology
By Melissa Chaika, November 1995
Review:Minerva's Machine
By Sara M. Carlstead, November 1995
“So how are your hands?”
By Rob Jackson, November 1995
Opinion: why are people afraid of computers?
By Scott Ramsey MacDonald, November 1995
Ojective View Point: getting the handle of handles
By G. Bowden Wise, November 1995
Ask Jack: confused about careers?
By Jack Wilson, November 1995
Down the Road: visit the University of Illinois at Urbana-Champaign
By Sara M. Carlstead, November 1995
By Lorrie Faith Cranor, November 1995
Road crew
By Lorrie Faith Cranor, November 1995
Networking: introduction
By Mark Allman, September 1995
The Internet's history and development
By Scott Ruthfield, September 1995
Website review: Charles Babbage Institute
By Ben W. Brumfield, September 1995
The MBONE
By Jay A. Kreibich, September 1995
Network security, filters and firewalls
By Darren Bolding, September 1995
Harvest
By Sarah Elizabeth Burcham, September 1995
The Fox Project
By Jeremy Buhler, September 1995
Objective View Point: the ABCs of writing C++ classes
By G. Bowden Wise, September 1995
Conference report: conferences offer insifhts into how computers may affect our future
By Lorrie Faith Cranor, Adam Lake, September 1995
Book review: Fatal Defect: Chasing Killer Computer Bug
By Saveen Reddy, September 1995
Down the road: meet our first European chapter
By Sara M. Carlstead, September 1995
Road crew
By Lorrie Faith Cranor, September 1995
From the editors: Crossroads finishes first year
By Ronald B. Krisko, May 1995
Speed is life, life is speed
By Scott Ramsey MacDonald, May 1995
Social responsibility and the CS student
By Saul Jimenez, May 1995
Digital liberties
By Lorrie Faith Cranor, May 1995
Direct democracy
By Adam Lake, May 1995
net.love
By Sara M. Carlstead, May 1995
Should computer scientists worry about ethics?
By Saveen Reddy, May 1995
Objective View Poiint: the ABCs of writing C++ classes
By G. Bowden Wise, May 1995
Down the Road: the first high school chapter
By Sara M. Carlstead, May 1995
Conference report: The 1995 ACM Big Event
By Ronald B. Krisko, May 1995
Objective View Point: object-orientation and C++ (part II of II)
By G. Bowden Wise, February 1995
The Road Less Traveled: an alternative review of Doom II
By Lorrie Faith Cranor, February 1995
Software Review: my humble opinions on Windows NT vs. OS/2
By Ronald B. Krisko, February 1995
Book Review: successful C++ book
By Saveen Reddy, February 1995
Road crew
By Lorrie Faith Cranor, February 1995
Editorial
By Saveen Reddy, December 1994
Programs worth one thousand words
By Lorrie Cranor, Ajay Apte, December 1994
An introduction to Scheme
By Shriram Krishnamurthi, December 1994
Objective View Point: object-orientation and C++ (part I of II)
By G. Bowden Wise, December 1994
In search of a customizable and uniform user interface
By Bradley M. Kuhn, David W. Binkley, December 1994
Book review: email style book jumps on the Internet bandwagon
By Lorrie Faith Cranor, December 1994
Software review: Doom 2
By Terry White, December 1994
Editorial
By Saveen Reddy, September 1994
Under the hood of the Internet
By Jason Yanowitz, September 1994
Objective View Point: an introduction to C++
By Saveen Reddy, G. Bowden Wise, September 1994
Book Reviews: serial communications books
By Saveen Reddy, September 1994
Software review: tie fighter
By Terry White, September 1994
Road crew
By Saveen Reddy, September 1994