ppxscal/embedding_network huggingface dataset:
Privacy in data systems
Authors: Rakesh Agrawal
Venue: Proceedings of the twenty-second ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems (2003)

The explosive progress in networking, storage, and processor technologies is resulting in an unprecedented amount of digitization of information. In concert with this dramatic increase in digital data, concerns about the privacy of personal information have emerged globally. The concerns over massive collection of data are naturally extending to analytic tools applied to data. Data mining, with its promise to efficiently discover valuable, non-obvious information from large databases, is particularly vulnerable to misuse.The challenge for the database community is to design information systems that protect the privacy and ownership of individual data without impeding information flow. One way of preserving privacy of individual data values is to perturb them. Since the primary task in data mining is the development of models about aggregated data, we explore if we can develop accurate models without access to precise information in individual data records. We consider the concrete case of building a decision-tree classifier from perturbed data. While it is not possible to accurately estimate original values in individual data records, we describe a reconstruction procedure to accurately estimate the distribution of original data values. By using these reconstructed distributions, we are able to build classifiers whose accuracy is comparable to the accuracy of classifiers built with the original data. We also discuss how to discover association rules over privacy preserved data.Inspired by the privacy tenet of the Hippocratic Oath, we argue that future database systems must include responsibility for the privacy of data they manage as a founding tenet. We enunciate the key principles for such Hippocratic database systems, distilled from the principles behind current privacy legislations and guidelines. We identify the technical challenges and problems in designing Hippocratic databases, and also outline some solution approaches.
Appropriating Value from Computerized Reservation System Ownership in the Airline Industry
Authors: Katherine A. Duliba, Robert J. Kauffman, Henry C. Lucas
Venue: Organization Science (2001)

It is difficult for the firm competing through information technology resources to gain a sustainable advantage because systems are easy to imitate and substitute resources are often available to competitors. The innovator may be unable to appropriate all of the benefits from information technology investments. Airlines have installed computerized reservations systems in travel agencies to appropriate the returns from their investments in information technology. The airlines expected to obtain a number of benefits from this strategy, including increased efficiency, possible bias in favor of the computerized reservations systems owner on the part of the travel agent, and fees from other airlines for making reservations for them. The purpose of this paper is to evaluate the appropriation of value by computerized reservations systems owners from deploying systems in travel agencies. These benefits, beyond fees from travel agents, should be seen in the vendor airline's market share between cities and in the overall performance of the airline at an industry level. This paper models airline performance as a function of computerized reservations systems ownership at two levels: for selected city-pairs and at the overall level of the firm. The city-pair analysis employs a multinomial logit market share model that analyzes five years of data on 72 city-pair routes. The industry model uses longitudinal data for a panel of 10 airlines for 12 years. The results of both analyses support hypotheses that computerized reservations systems ownership is positively related to airline performance. It appears that strong airlines have appropriated the benefits of their computerized reservations systems, turning them into highly specialized assets for further travel-related innovation. This work offers useful theoretical extensions and methodological approaches for the study of similar kinds of network technology innovations that are currently being deployed in association with electronic commerce on the Internet.
Airline Fleet Assignment with Time Windows
Authors: Brian Rexing, Cynthia Barnhart, Tim Kniker, Ahmad Jarrah, Nirup Krishnamurthy
Venue: Transportation Science (2000)

Recognizing that allowing variability in scheduled flight departure times can result in improved flight connection opportunities and a more cost effective fleet assignment, we present a generalized fleet assignment model for simultaneously assigning aircraft types to flights and scheduling flight departures. Our model, a simple variant of basic fleet assignment models, assigns a time window to each flight and then discretizes each window, allowing flight departure times to be optimized. Because problem size can become formidable, much larger than basic fleet assignment models, we develop two algorithmic approaches for solving the model. Our direct solution approach is good for speed and simplicity, whereas our iterative technique minimizes memory usage. Using data from a major U.S. airline, we show that our model can solve real, large-scale problems, and we evaluate the effects of schedule flexibility. In every test scenario, the model produces a fleet assignment with significantly lower costs than the basic model, and, in a separate analysis, the model is used to tighten the schedule, potentially saving aircraft.
Microelectromechanical systems (MEMS) tutorial
Authors: Kaigham J. Gabriel
Venue: Proceedings of the 1998 IEEE International Test Conference (1998)

As information systems increasingly leave fixed locations and appear in ourpockets and palms, they are getting closer to the physical world, creatingnew opportunities for perceiving and controlling our machines, structuresand environments. To exploit these opportunities, information systems willneed to sense and act as well as compute. Investing engineered systems withsuperior capabilities to sense and act is the driving force for the developmentof microelectromechanical systems (MEMS).Using the fabrication techniques and materials of microelectronics as abasis, MEMS processes construct both mechanicaL and electrical components.Mechanical components in MEMS, like transistors in microelectronics,have dimensions that are measured in microns and numbers measuredfrom a few to millions. MEMS is not about any one single application ordevice, nor is it defined by a single fabrication process or limited to a fewmaterials. More than anything else, MEMS is a fabrication approach thatconveys the advantages of miniaturization, multiple components and microelectronicsto the design and construction of integrated electromechanicalsystems.MEMS devices have applications in areas ranging from automobiles andtelecom switching to printers and inertial guidance systems. While MEMSdevices will be a relatively small fraction of the cost, size and weight of thesesystems, MEMS will be critical to their operation, reliability and affordabilityMEMS devices, and the smart products they enable, will increasingly bethe performance differentiator for a wide variety of commercial products.
A Delay-Averaged Logistic Model
Authors: M. Yu. Vagina
Venue: Automation and Remote Control (2003)

For the equation \dot x(t) = &epsiv;x(t) (1-(1/&tau;) &int;t-&thetas;-&tau;t-&thetas;x(u)du), &epsiv; > 0, &thetas; > 0, &tau; > 0, conditions for the stability of a nonzero stationary solution under small perturbations are determined.
Dynamic Planar Convex Hull
Authors: Gerth Stølting Brodal, Riko Jacob
Venue: Proceedings of the 43rd Symposium on Foundations of Computer Science (2002)

In this paper we determine the computational complexity of the dynamic convex hull problem in the planar case. We present a data structure that maintains a finite set of n points in the plane under insertion and deletion of points in amortized O(log n) time per operation. Thespace usage of the data structure is O(n). The data structure supports extreme point queries in a given direction, tangent queries through a given point, and queries for the neighboring points on the convex hull in O(log n) time. The extreme point queries can be used to decide whether or not a given line intersects the convex hull, and the tangent queries to determine whether a given point is inside the convex hull. We give a lower bound on the amortized asymptotic time complexity that matches the performance of this data structure.
An Internet-based negotiation server for e-commerce
Authors: Stanley Y.W. Su, Chunbo Huang, Joachim Hammer, Yihua Huang, Haifei Li, Liu Wang, Youzhong Liu, Charnyote Pluempitiwiriyawej, Minsoo Lee, Herman Lam
Venue: The VLDB Journal &mdash; The International Journal on Very Large Data Bases (2001)

This paper describes the design and implementation of a replicable, Internet-based negotiation server for conducting bargaining-type negotiations between enterprises involved in e-commerce and e-business. Enterprises can be buyers and sellers of products/services or participants of a complex supply chain engaged in purchasing, planning, and scheduling. Multiple copies of our server can be installed to complement the services of Web servers. Each enterprise can install or select a trusted negotiation server to represent his/her interests. Web-based GUI tools are used during the build-time registration process to specify the requirements, constraints, and rules that represent negotiation policies and strategies, preference scoring of different data conditions, and aggregation methods for deriving a global cost-benefit score for the item(s) under negotiation. The registration information is used by the negotiation servers to automatically conduct bargaining type negotiations on behalf of their clients. In this paper, we present the architecture of our implementation as well as a framework for automated negotiations, and describe a number of communication primitives which are used in the underlying negotiation protocol. A constraint satisfaction processor (CSP) is used to evaluate a negotiation proposal or counterproposal against the registered requirements and constraints of a client company. In case of a constraint violation, an event is posted to trigger the execution of negotiation strategic rules, which either automatically relax the violated constraint, ask for human intervention, invoke an application, or perform other remedial operations. An Event-Trigger-Rule (ETR) server is used to manage events, triggers, and rules. Negotiation strategic rules can be added or modified at run-time. A cost-benefit analysis component is used to perform quantitative analysis of alternatives. The use of negotiation servers to conduct automated negotiation has been demonstrated in the context of an integrated supply chain scenario.
A Note on Approximating Peak Congestion in MT/G/Infinity Queues with Sinusoidal Arrivals
Authors: Linda V. Green, Peter J. Kolesar
Venue: Management Science (1998)

We study the Mt /G/infinity queue where customers arrive according to a sinusoidal function &#955;t= &#955; + A sin(2&#960;t/T) and the service rate is &#956;. We show that the expected number of customers in the system during peak congestion can be closely approximated by (&#955; + A)/&#956; for service distributions with coefficient of variation between 0 and 1. Motivated by a result derived by Eick, Massey, and Whitt that the time lag of the peak congestion from the peak of the customer arrivals is 1/2&#956; for models with deterministic service times, we show that the time lag for exponential service times is closely approximated by 1/&#956;. Based on a cycle length of 24 hours and regardless of the values of other system parameters, these approximations are of the order of 1% accuracy for &#956; = 1, and the accuracy increases rapidly with increasing &#956;.
Microcontinuum approach in biomechanical modeling
Authors: Josef Rosenberg, Robert Cimrman
Venue: Mathematics and Computers in Simulation (2003)

The living organs consist of tissues characterized by the hierarchical, very complex inner structure. One of theories taking this into account is the microcontinuum theory elaborated by Eringen [Microcontinuum Field Theories: Foundation and Solids, 1998]. The corresponding mathematical formulation is rather complicated, and therefore, the numerical application is still in progress. In this contribution, the boundary value problem for micropolar and microstretch linear continuum is defined. Using the author's formalism [ZAMM 65 (1985) 417; J. Computat. Appl. Math. 53 (1995) 307] which is based on Buffer's work [Ingenieur-Arch. 45 (1976) 17] the corresponding variational principles are developed. These are used for the numerical implementation. The code for micropolar continuum is tested on some examples and used for the bone modeling.
Developing and enhancing a client/server programming for internet applications course
Authors: W. Sam Chung, Don McLane
Venue: Journal of Computing Sciences in Colleges (2002)

The purpose of this paper is to describe the development and enhancement of a Client/Server (C/S) programming for Internet applications course in Computer Science (CS) curriculum. If a CS program has used Java as the first programming language and the program does not have enough resources to support the C/S course development with proprietary environments, it will bring an issue: how can we develop and enhance the C/S programming for Internet applications course? We develop the course by integrating multi-tier architecture, Web technologies, Java technologies, and open source software into the teaching material of the course. Also, the instructor provides the students various laboratory settings, which is called an Active Learning Environment in Computing (ALEC), to enhance the course through the strong hands-on practices of the students.Our approaches for developing and enhancing the C/S programming for Internet applications course can bring several benefits to students, instructor, and the institution. First, the students can smoothly understand the course materials without having the sharp learning curve when studying the Java-related technologies such as JavaScript, JSP, JavaBean, and JDBC if Java is used as the first programming language in the institution of the students. Second, by using the system administration lab, the students can have strong hands-on practices by building their client/server computing environments for themselves. These practices can help the instructors to teach multi-tier architectures and other C/S computing models. Third, by using open source software, the institution can minimize the cost of the computing environment for the course. In addition, if the institution has been predominantly exposed to Windows environment, the open source software can bring another diversity in software to the institution.
How Leaders Foster Self-Managing Team Effectiveness: Design Choices Versus Hands-on Coaching
Authors: Ruth Wageman
Venue: Organization Science (2001)

This multi-method field study examines the relative effects of two kinds of leader behaviors--design choices and hands-on coaching--on the effectiveness of self-managing teams. Findings show that how leaders design their teams and the quality of their hands-on coaching both influence team self-management, the quality of member relationships, and member satisfaction, but only leaders' design activities affect team task performance. Moreover, design and coaching interact, so that well-designed teams are helped more by effective coaching--and undermined less by ineffective coaching--than are poorly designed teams.
Variance Reduction in Simulations of Loss Models
Authors: Rayadurgam Srikant, Ward Whitt
Venue: Operations Research (1999)

We propose a new estimator of steady-state blocking probabilities for simulations of stochastic loss models that can be much more efficient than the natural estimator (ratio of losses to arrivals). The proposed estimator is a convex combination of the natural estimator and an indirect estimator based on the average number of customers in service, obtained from Little's law (L = &#955;W). It exploits the known offered load (product of the arrival rate and the mean service time). The variance reduction is dramatic when the blocking probability is high and the service times are highly variable. The advantage of the combination estimator in this regime is partly due to the indirect estimator, which itself is much more efficient than the natural estimator in this regime, and partly due to strong correlation (most often negative) between the natural and indirect estimators. In general, when the variances of two component estimators are very different, the variance reduction from the optimal convex combination is about 1 - &#961;2, where &#961; is the correlation between the component estimators. For loss models, the variances of the natural and indirect estimators are very different under both light and heavy loads. The combination estimator is effective for estimating multiple blocking probabilities in loss networks with multiple traffic classes, some of which are in normal loading while others are in light and heavy loading, because the combination estimator does at least as well as either component estimator, and it provides improvement as well.
Automatic test selection based on CEFSM specifications
Authors: Gábor Kovács, Zoltán Pap, Gyula Csopaki
Venue: Acta Cybernetica (2002)

Mutation analysis is a fault based testing method used initially for code based software testing. In this paper, this method is applied to formal specifications and used for automatic conformance test selection. This paper defines formally a set of mutation operators for CEFSM (Communicating Extended Finite State Machine) systems to enable the automated creation of mutant specifications. Mutants of a specification are used as selection criteria to pick out adequate test cases. Two different algorithms are proposed for the generation and selection of efficient test suites. Additionally, the operators and algorithms provide the basis of an automatic tool developed at the Budapest University of Technology and Economics. We present the results of an empirical study on the well-known INRES protocol acquired using the tool.
Assured forwarding fairness using equation-based packet marking and packet separation
Authors: Mohamed A. El-Gendy, Kang G. Shin
Venue: Computer Networks: The International Journal of Computer and Telecommunications Networking (2003)

Fairness is one of the important problems in assured forwarding (AF) performance in the differentiated services (DiffServ) framework [An architecture for differentiated services, RFC 2475, IETF, December 1998; A two-bit differentiated services architecture for the Internet, Internet-draft, draft-nichols-diff-svc-arch-02.pdf, IETF, April I999]. In this paper we present a two-part solution for the fairness problem in AF. The first part is a new packet marking algorithm called equation-based marking (EBM) and is based on the TCP model given by Padhye et al. [Modeling TCP throughput: A simple model and its empirical validation, in: Proceedings of ACM SIGCOMM '98, October 1998]. EBM is to handle the problems found in other marking schemes regarding fairness among heterogeneous TCP flows through a tight feedback-loop operation and adaptation of the packet marking probability to network conditions. The second part is called packet separation used at routers to handle the fairness between responsive and nonresponsive traffic. We evaluate the performance of a packet marker that uses EBM as the marking algorithm using in-depth simulation. We prove, analytically and using simulation, the correctness of the marking algorithm and compare it with other marking schemes for different network scenarios. We also use simulation to show the effectiveness of the packet separation mechanism in solving the fairness problem between responsive and non-responsive traffic. Our evaluation results demonstrate the effectiveness of EBM along with packet separation in providing the required fairness among heterogeneous flows and ensuring protection against non-assured traffic.
Task scheduling and data management
Authors: Alan Chalmers
Venue: Practical parallel rendering (2002)

The efficient solution of a problem on a parallel system requires the computational performance of the processing elements to be fully utilized. Any processing element that is not busy performing useful computations is degrading overall system performance. Task scheduling strategies may be used to minimize these potential performance limitations.
Measurement of user frustration: a biologic approach
Authors: Richard Hazlett
Venue: CHI '03 extended abstracts on Human factors in computing systems (2003)

This paper describes the use of facial EMG to provide a continuous measure of the user's emotional state. Facial EMG was recorded while female users performed five tasks to one of two web sites. Frustration index scores were developed from the corrugator EMG data by calculating a percentage score of a pre-task baseline. As predicted, the frustration index was greater for (1) novices as compared to experienced users, (2) incorrect as compared to correct answered tasks, and (3) for the web site that was rated more difficult. The frustration index was able to provide important information on web page performance.
A Heuristic Search Approach for a Nonstationary Stochastic Shortest Path Problem with Terminal Cost
Authors: James L. Bander, Chelsea C. White
Venue: Transportation Science (2002)

We present a best-first heuristic search approach for determining an optimal policy for a stochastic shortest path problem. A vehicle is to travel from an origin, starting at timet0, to a destination, where once the destination is reached a terminal cost is accrued. The terminal cost depends on the time of arrival. Travel time along each arc in the network is modeled as a random variable with a distribution dependent on the time that travel along the arc is begun. The objective is to determine a routing policy that minimizes expected total cost. A routing policy is a rule that assigns the next arc to traverse, given the current node and time.The heuristic search algorithm that we specialize to this stochastic problem is AO *. We demonstrate the significant computational advantages of AO *, relative to dynamic programming, on the basis of run time and storage, using a 131-intersection network of the major roads in Cleveland, Ohio. Further computational experience is based on grid networks that were randomly generated to have characteristics similar to transportation networks, and on randomly generated unstructured networks.
What do types mean?: from intrinsic to extrinsic semantics
Authors: John C. Reynolds
Venue: Programming methodology (2003)

A definition of a typed language is said to be "intrinsic" if it assigns meanings to typings rather than arbitrary phrases, so that ill-typed phrases are meaningless. In contrast, a definition is said to be "extrinsic" if all phrases have meanings that are independent of their typings, while typings represent properties of these meanings.For a simply typed lambda calculus, extended with integers, recursion, and conditional expressions, we give an intrinsic denotational semantics and a denotational semantics of the underlying untyped language. We then establish a logical relations theorem between these two semantics, and show that the logical relations can be "bracketed" by retractions between the domains of the two semantics. From these results, we derive an extrinsic semantics that uses partial equivalence relations.