University of Pennsylvania

Displaying 1-40 of 160 results

  • White Papers // May 2012

    TROPIC: Transactional Resource Orchestration Platform in the Cloud

    Realizing Infrastructure-as-a-Service (IaaS) cloud requires a control platform to orchestrate cloud resource provisioning, configuration, and decommissioning across a distributed set of diverse physical resources. This orchestration is challenging due to the rapid growth of data centers, high failure rate of commodity hardware and the increasing sophistication of cloud services. This...

    Provided By University of Pennsylvania

  • White Papers // Mar 2012

    Cologne: A Declarative Distributed Constraint Optimization Platform

    This paper presents Cologne, a declarative optimization platform that enables Constraint Optimization Problems (COPs) to be declaratively specified and incrementally executed in distributed systems. Cologne integrates a declarative networking engine with an off-the-shelf constraint solver. The authors have developed the Colog language that combines distributed Datalog used in declarative networking...

    Provided By University of Pennsylvania

  • White Papers // Mar 2012

    Rehoming Edge Links for Better Traffic Engineering

    Traditional traffic engineering adapts the routing of traffic within the network to maximize performance. The authors propose a new approach that also adaptively changes where traffic enters and leaves the network - changing the "Traffic matrix", and not just the intra-domain routing configuration. Their approach does not affect traffic patterns...

    Provided By University of Pennsylvania

  • White Papers // Feb 2012

    Irrelevance, Heterogeneous Equality, and Call-by-Value Dependent Type Systems

    The authors present a full-spectrum dependently typed core language which includes both non-termination and computational irrelevance (a.k.a. erasure), a combination which has not been studied before. The two features interact: to protect type safety they must be careful to only erase terminating expressions. Their language design is strongly influenced by...

    Provided By University of Pennsylvania

  • White Papers // Jan 2012

    Virtual Switching Without a Hypervisor for a More Secure Cloud

    Cloud computing leverages virtualization to offer resources on demand to multiple "Tenants". However, sharing the server and network infrastructure creates new vulnerabilities, where one tenant can attack another by compromising the underlying hypervisor. The authors design a system that supports virtualized networking using software switches without a hypervisor. In the...

    Provided By University of Pennsylvania

  • White Papers // Dec 2011

    Step-Indexed Normalization for a Language With General Recursion

    The TRELLYS project has produced several designs for practical dependently typed languages. These languages are broken into two fragments - a logical fragment where every term normalizes and which is consistent when interpreted as a logic, and a programmatic fragment with general recursion and other convenient, but unsound features. In...

    Provided By University of Pennsylvania

  • White Papers // Sep 2011

    Partial Specification of Routing Configurations

    The formal analysis of routing protocol configurations for safety properties is well established. Methods exist to identify potential protocol oscillations by analysis of the network topology and route preference information. However, if not all of this information is available, then the existing theory does not apply. The authors present an...

    Provided By University of Pennsylvania

  • White Papers // Sep 2011

    Secure Network Provenance

    This paper introduces Secure Network Provenance (SNP), a novel technique that enables networked systems to explain to their operators why they are in a certain state - e.g., why a suspicious routing table entry is present on a certain router, or where a given cache entry originated. SNP provides network...

    Provided By University of Pennsylvania

  • White Papers // Aug 2011

    Declarative Policy-Based Adaptive Mobile Ad Hoc Networking

    This paper presents DAWN, a declarative platform that creates highly adaptive policy-based MANET protocols. DAWN leverages declarative networking techniques to achieve extensible routing and forwarding using declarative languages. The authors make the following contributions. First, they demonstrate that traditional MANET protocols can be expressed in a concise fashion as declarative...

    Provided By University of Pennsylvania

  • White Papers // Jun 2011

    Differential Privacy Under Fire

    Anonymizing private data before release is not enough to reliably protect privacy, as Netflix and AOL have learned to their cost. Recent research on differential privacy opens a way to obtain robust, provable privacy guarantees, and systems like PINQ and Airavat now offer convenient frameworks for processing arbitrary user-specified queries...

    Provided By University of Pennsylvania

  • White Papers // May 2011

    MOSAIC: Declarative Platform for Dynamic Overlay Composition

    Overlay networks create new networking services using nodes that communicate using pre-existing networks. They are often optimized for specific applications and targeted at niche vertical domains, but lack interoperability with which their functionalities can be shared. MOSAIC is a declarative platform for constructing new overlay networks from multiple existing overlays,...

    Provided By University of Pennsylvania

  • White Papers // May 2011

    TAP: Time-Aware Provenance for Distributed Systems

    In this paper, the authors explore the use of provenance for analyzing execution dynamics in distributed systems. They argue that provenance could have significant practical benefits for system administrators, e.g., for reasoning about changes in a system's state, diagnosing protocol misconfigurations, detecting intrusions, and pinpointing performance bottlenecks. However, to realize...

    Provided By University of Pennsylvania

  • White Papers // Apr 2011

    Discriminative ImageWarping With Attribute Flow

    The authors address the problem of finding deformation between two images for the purpose of recognizing objects. The challenge is that discriminative features are often transformation-variant (e.g. histogram of oriented gradients, texture), while transformation-invariant features (e.g. intensity, color) are often not discriminative. They introduce the concept of attribute flow which...

    Provided By University of Pennsylvania

  • White Papers // Apr 2011

    AS-TRUST: A Trust Quantification Scheme for Autonomous Systems in BGP

    The Border Gateway Protocol (BGP) works by frequently exchanging updates that disseminate reachability information about IP prefixes (i.e., IP address blocks) between Autonomous Systems (ASes) on the Internet. The ideal operation of BGP relies on three major behavioral assumptions (BAs): Information contained in the update is legal and correct, a...

    Provided By University of Pennsylvania

  • White Papers // Apr 2011

    Network Neutrality Or Internet Innovation?

    Network neutrality has received sustained attention from both policymakers and academic commentators for the past several years, and it shows no signs of retreating from the forefront of the policy debate. President Obama effectively ensured that network neutrality will remain at the top of the policy agenda by including provisions...

    Provided By University of Pennsylvania

  • White Papers // Mar 2011

    Portfolio Optimization in Secondary Spectrum Markets

    In this paper, the authors address the Spectrum Portfolio Optimization (SPO) question in the context of secondary spectrum markets, where bandwidth (spectrum access rights) can be bought in the form of primary and secondary contracts. While a primary contract on a channel provides guaranteed access to the channel bandwidth (possibly...

    Provided By University of Pennsylvania

  • White Papers // Mar 2011

    An Open-Source and Declarative Approach Towards Teaching Large-Scale Networked Systems Programming

    This paper describes the authors' experiences at the University of Pennsylvania in developing course projects for a large advanced undergraduate and first year graduate course in networked systems. Students work in teams to develop substantial networked systems programming projects (>10000 lines of code) using network simulator 3 (ns-3), an emerging...

    Provided By University of Pennsylvania

  • White Papers // Mar 2011

    Reoccurring Financial Crises In The United States

    The economic history of the United States is riddled with financial crises and banking panics. During the nineteenth-century, eight major such episodes occurred. In the period following World War II, some believed that these crises would no longer happen, and that the U.S. had reached a time of everlasting financial...

    Provided By University of Pennsylvania

  • White Papers // Mar 2011

    A Monetary Theory With Non-Degenerate Distributions

    Dispersion of money balances among individuals is the basis for a range of policies but it has been abstracted from in monetary theory for tractability reasons. In this paper, the authors fill in this gap by constructing a tractable search model of money with a non-degenerate distribution of money holdings....

    Provided By University of Pennsylvania

  • White Papers // Feb 2011

    Pro-Cyclical Unemployment Benefits? Optimal Policy In An Equilibrium Business Cycle Model

    The authors study the optimal provision of Unemployment Insurance (UI) over the business cycle. They consider an equilibrium Mortensen-Pissarides search and matching model with risk-averse workers and aggregate shocks to labor productivity. Both the vacancy creation decisions of firms and the search e ort decisions of workers respond endogenously to...

    Provided By University of Pennsylvania

  • White Papers // Feb 2011

    An Operational Semantics for Network Datalog

    Network Datalog (NDlog) is a recursive query language that extends Datalog by allowing programs to be distributed in a network. In the authors' initial efforts to formally specify NDlog's operational semantics, they have found several problems with the current evaluation algorithm being used, including unsound results, unintended multiple derivations of...

    Provided By University of Pennsylvania

  • White Papers // Feb 2011

    Formally Verifiable Networking

    This paper proposes Formally Verifiable Networking (FVN), a novel approach towards unifying the design, specification, implementation, and verification of networking protocols within a logic-based framework. In FVN, formal logical statements are used to specify the behavior and the properties of the protocol. FVN uses declarative networking as an intermediary layer...

    Provided By University of Pennsylvania

  • White Papers // Feb 2011

    Optimal Routing and Scheduling in Multihop Wireless Renewable Energy Networks

    In this paper, the authors design routing and scheduling policies that optimize network throughput in energy-constrained wireless ad-hoc networks where nodes are powered by renewable energy sources. They take into account the fact that renewable energy harvesting processes are unpredictable and stochastic in nature - typically depending on environmental factors...

    Provided By University of Pennsylvania

  • White Papers // Jan 2011

    What Should Central Banks Do About Real Estate Prices?

    Many central banks use inflation targeting as the basis for their monetary policy. The underlying notion of this approach is that there are no long term benefits in terms of reduced unemployment from having inflation. The traditional view is that monetary policy should focus on controlling consumer price inflation. Asset...

    Provided By University of Pennsylvania

  • White Papers // Jan 2011

    Spectrum Pricing Games With Spatial Reuse in Cognitive Radio Networks

    In Cognitive Radio Networks (CRN), there are multiple primary and secondary users in a region, and primaries can lease out their unused bandwidth to secondaries in exchange for a fee. This gives rise to price competition among the primaries, wherein each primary tries to attract secondaries by setting a lower...

    Provided By University of Pennsylvania

  • White Papers // Jan 2011

    Moment-Based Analysis of Spreading Processes from Network Structural Information

    The intricate structure of many large-scale networked systems has attracted the attention of the scientific community, leading to many results attempting to explain the relationship between network structural properties and dynamical performance. A common approach to study this relationship is the usage of synthetic network models in which the researcher...

    Provided By University of Pennsylvania

  • White Papers // Jan 2011

    Cloud Resource Orchestration: A DataCentric Approach

    Cloud computing provides users near instant access to seemingly unlimited resources, and provides service providers the opportunity to deploy complex information technology infrastructure, as a service, to their customers. Providers benefit from economies of scale and multiplexing gains afforded by sharing of resources through virtualization of the underlying physical infrastructure....

    Provided By University of Pennsylvania

  • White Papers // Jan 2011

    Characterizing Temporal SNR Variation in 802.11 Networks

    The analysis and design of wireless MAC protocols, coding schemes and transmission algorithms can significantly benefit from an understanding of the channel quality variation. The authors attempt to represent channel quality variation using a finite state birth-death Markov model. The authors outline a method to compute the parameters of the...

    Provided By University of Pennsylvania

  • White Papers // Jan 2011

    Multiplicative Updates for Large Margin Classifiers

    Various problems in nonnegative quadratic programming arise in the training of large margin classifiers. The authors derive multiplicative updates for these problems that converge monotonically to the desired solutions for hard and soft margin classifiers. The updates differ strikingly in form from other multiplicative updates used in machine learning. In...

    Provided By University of Pennsylvania

  • White Papers // Jan 2011

    Languages of Nested Trees

    The authors study languages of nested trees-structures obtained by augmenting trees with sets of nested jump-edges. These graphs can naturally model branching behaviors of push-down programs, so that the problem of branching-time software model checking may be phrased as a membership question for such languages. They define finite-state automata accepting...

    Provided By University of Pennsylvania

  • White Papers // Jan 2011

    Arbitrary Throughput Versus Complexity Tradeoffs in Wireless Networks Using Graph Partitioning

    Several policies have recently been proposed for attaining the maximum throughput region, or a guaranteed fraction thereof, through dynamic link scheduling. Among these policies, the ones that attain the maximum throughput region require a computation time which is linear in the network size, and the ones that require constant or...

    Provided By University of Pennsylvania

  • White Papers // Jan 2011

    Encoding Information Flow in Haskell

    This paper presents an embedded security sublanguage for enforcing information-flow policies in the standard Haskell programming language. The sublanguage provides useful information-flow control mechanisms including dynamic security lattices, run-time code privileges and declassification, without modifying the base language. This design avoids the redundant work of producing new languages, lowers the...

    Provided By University of Pennsylvania

  • White Papers // Dec 2010

    Information, Liquidity, Asset Prices And Monetary Policy Second Version

    What determines which assets are used in transactions? The authors develop a framework where the extent to which assets are recognizable determines the extent to which they are acceptable in exchange - i.e., their liquidity. They analyze the effects of monetary policy on asset markets. Recognizability and liquidity are endogenized...

    Provided By University of Pennsylvania

  • White Papers // Dec 2010

    Enabling Privacy in Provenance-Aware Workflow Systems

    A new paradigm for creating and correcting scientific analyses is emerging, that of provenance-aware workflow systems. In such systems, repositories of workflow specifications and of provenance graphs that represent their executions will be made available as part of scientific information sharing. This will allow users to search and query both...

    Provided By University of Pennsylvania

  • White Papers // Nov 2010

    Pricing And Investments In Matching Markets Second Version

    Different markets are cleared by different types of prices-seller-specific prices that are uniform across buyers in some markets, and personalized prices tailored to the buyer in others. The authors examine a setting in which buyers and sellers make investments before matching in a competitive market. They introduce the notion of...

    Provided By University of Pennsylvania

  • White Papers // Nov 2010

    Changing Institutional Preferences And Investment Performance: A Stock Holdings Perspective

    Institutional investors have rapidly increased their percentage holdings of US equities in recent years. In this paper the authors update previous research on the nature of institutional stock ownership, extending the evidence by twelve years to the end of 2008. In contrast to previous research, they find that institutions, and...

    Provided By University of Pennsylvania

  • White Papers // Nov 2010

    Asset Commonality, Debt Maturity And Systemic Risk

    The authors develop a model where financial institutions swap projects in order to diversify their individual risk. This can lead to two different asset structures. In a clustered structure groups of financial institutions hold identical portfolios and default together. In an un-clustered structure defaults are more dispersed. With long term...

    Provided By University of Pennsylvania

  • White Papers // Nov 2010

    Deriving Probabilistic Databases With Inference Ensembles

    Many real-world applications deal with uncertain or missing data, prompting a surge of activity in the area of probabilistic databases. A shortcoming of prior work is the assumption that an appropriate probabilistic model, along with the necessary probability distributions, is given. This paper addresses this shortcoming by presenting a framework...

    Provided By University of Pennsylvania

  • White Papers // Nov 2010

    Quantifying The Impact Of Financial Development On Economic Development

    How important is financial development for economic development? A costly state verification model of financial intermediation is presented to address this question. The model is calibrated to match facts about the U.S. economy, such as intermediation spreads and the firm-size distribution for the years 1974 and 2004. It is then...

    Provided By University of Pennsylvania

  • White Papers // Oct 2010

    Expressiveness of Streaming String Transducers

    Streaming string transducers define (partial) functions from input strings to output strings. A streaming string transducer makes a single pass through the input string and uses a finite set of variables that range over strings from the output alphabet. At every step, the transducer processes an input symbol, and updates...

    Provided By University of Pennsylvania

  • White Papers // Oct 2008

    Reasoning About Keys for XML

    This paper studies absolute and relative keys for XML, and investigates their associated decision problems. It is argued that these keys are important to many forms of hierarchically structured data including XML documents. In contrast to other proposals of keys for XML, these keys can be reasoned about efficiently. The...

    Provided By University of Pennsylvania

  • White Papers // Oct 2008

    Validating Constraints in XML

    The role of XML in data exchange is evolving from one of merely conveying the structure of data to one that also conveys its semantics. In particular, several proposals for key and foreign key constraints have recently appeared, and aspects of these proposals have been adopted within XMLSchema. Although several...

    Provided By University of Pennsylvania

  • White Papers // Oct 2008

    Querying XML With Mixed and Redundant Storage

    This paper examines some of the issues that arise in the process of XML publishing of mixed-storage proprietary data. It is argued that such data will reside typically in RDBMS's and/or LDAP, etc, augmented with a set of native XML documents. An additional challenge is to take advantage of redundancy...

    Provided By University of Pennsylvania

  • White Papers // Oct 2008

    Using XQuery to Build Updatable XML Views Over Relational Databases

    XML has become an important medium for data exchange, and is frequently used as an interface to - i.e. a view of - a relational database. Although much attention has been paid to the problem of querying relational databases through XML views, the problem of updating relational databases through XML...

    Provided By University of Pennsylvania

  • White Papers // Oct 2008

    Reasoning About the Updatability of XML Views Over Relational Databases

    XML has become an important medium for data exchange, and is also used as an interface to - i.e. a view of - a relational database. While previous work has considered XML views for the purpose of querying relational databases (e.g. Silkroute), in this paper the problem of updating a...

    Provided By University of Pennsylvania

  • White Papers // Oct 2008

    XML Vectorization: A Column-Based XML Storage Model

    The usual method for storing tables in a relational database is to store each tuple contiguously in secondary storage. A simple alternative is to store the columns contiguously, so that a table is represented as a set of vectors all of the same length. It has been shown that such...

    Provided By University of Pennsylvania

  • White Papers // Dec 2008

    The Art Of Making Quality Decisions

    It's challenge enough for individuals to make decisions about things they know a lot about. It's even tougher for them to make decisions in the face of uncertainty or when the information available is being poked, prodded and packaged to influence their decisions. In order to make sound decisions, it's...

    Provided By University of Pennsylvania

  • White Papers // Aug 2009

    Maximum Damage Malware Attack in Mobile Wireless Networks

    Malware attacks constitute a serious security risk that threatens to slow down the large scale proliferation of wireless applications. As a first step towards thwarting this security threat, one seeks to quantify the maximum damage inflicted on the system owing to such outbreaks and identify the most vicious attacks. This...

    Provided By University of Pennsylvania

  • White Papers // Apr 2009

    The Social Life of Wireless Urban Spaces: Internet Use, Social Networks, and the Public Realm

    Offlate changes to the structure of people's social networks, the mass media, and urban public spaces may represent a confluence of social trends that constrain exposure to diverse issues, ideas, and opinions in the public sphere. Technological change that influences how it maintains social networks, access information, and use public...

    Provided By University of Pennsylvania

  • White Papers // Jul 2009

    Seventh Amendment: Sarbanes-Oxley Act Whistleblower Claims and Jury Trials

    In the early part of the twenty-first century, corporate fraud and greed led to the downfall of two major multinational corporations, Enron and WorldCom. Corporate scandals caught the attention of the general public, corporations, Wall Street, and Congress like few scandals ever have before.' The primary victims of the scandals-company...

    Provided By University of Pennsylvania

  • White Papers // Jan 2010

    Dynamic Malware Attack in Energy-Constrained Mobile Wireless Networks

    Large scale proliferation of wireless technologies are dependent on developing reliable security measures against outbreaks of malware. The first step toward this goal is investigating the possible attack strategies of wireless malware and the extent of damage they can incur. A malware in a mobile wireless network relies on the...

    Provided By University of Pennsylvania

  • White Papers // Jan 2010

    Optimal Malware Attack and Defense in Mobile Wireless Networks

    Malicious self-replicating codes, known as malware, pose substantial threat to the wireless computing infrastructure. Malware can be used to launch attacks that vary from the less intrusive confidentiality or privacy attacks, such as traffic analysis and eavesdropping, to the more intrusive methods that either disrupt the nodes normal functions such...

    Provided By University of Pennsylvania

  • White Papers // Feb 2009

    Optimal Quarantining of Wireless Malware Through Power Control

    The topic of malware propagation in mobile wireless networks is gaining momentum among the research community, as actual vulnerabilities are revealed through recent outbreaks of worms. The paper introduces a defense strategy that quarantines the malware by reducing the communication range. This countermeasure faces one to a trade-off: reducing the...

    Provided By University of Pennsylvania

  • White Papers // Dec 2009

    On the Feasibility and Efficacy of Protection Routing in IP Networks

    The protection routing procedures in IP networks has become a matter of great research and improvement owing to the growing demands of the resources available on the internet. Some of the major improvements have been required owing to the growing demand of quality of the internet services, and that involves...

    Provided By University of Pennsylvania

  • White Papers // Apr 2009

    Learning Sparse Markov Network Structure via Ensemble-of-Trees Models

    Learning the sparse structure of a general Markov network is a hard computational problem. One of the main difficulties is the computation of the generally intractable partition function. To circumvent this difficulty, authors propose to learn the network structure using an ensemble-of-trees (ET) model. The ET model was first introduced...

    Provided By University of Pennsylvania

  • White Papers // Apr 2010

    Deebee: General, Personal and Relational Database Management System for Casual Users

    deebee is a general, personal and relational database management system specifically designed for casual users who have no knowledge of database concepts. Currently, users have heaps of data that they need to manage without any niche applications to help them. Thus, authors will create a general data management system based...

    Provided By University of Pennsylvania

  • White Papers // Aug 2008

    Collaborative CME Using Web 2.0 Technologies

    Continuing medical education (CME) programs are poised to take advantage of the new technology, which allows for multidirectional exchanges, even when the participants are physically removed from one another. While, in the past, CME has often been presented as unidirectional (knowledge flowing from experts to participants), in reality, physicians commonly...

    Provided By University of Pennsylvania

  • White Papers // Oct 2008

    Combining Events and Threads for Scalable Network Services: Implementation and Evaluation of Monadic, Application-Level Concurrency Primitives

    This paper proposes to combine two seemingly opposed programming models for building massively concurrent network services: the event-driven model and the multithreaded model. The result is a hybrid design that offers the best of both worlds - the ease of use and expressiveness of threads and the flexibility and performance...

    Provided By University of Pennsylvania

  • White Papers // Jan 2010

    Individual QoS Versus Aggregate QoS: A Loss Performance Study

    This paper explores, primarily by means of analysis, the differences that can exist between individual and aggregate loss guarantees in an environment where guarantees are only provided at an aggregate level. The focus is on understanding which traffic parameters are responsible for inducing possible deviations and to what extent. In...

    Provided By University of Pennsylvania

  • White Papers // Jan 2010

    QoS Routing in Networks With Inaccurate Information: Theory and Algorithms

    QoS mechanisms can be categorized into two groups based on how the application traffic is treated: traffic handling mechanisms, and bandwidth management mechanisms. The lowest service level that a network can provide is best effort service which does not provide QoS support. In best effort service, all traffic is handled...

    Provided By University of Pennsylvania

  • White Papers // Jan 2010

    Web Ecology: Recycling HTML Pages as XML Documents Using W4F

    This paper presents the World-Wide Web Wrapper Factory (W4F), a Java toolkit to generate wrappers for Web data sources. Some key features of W4F are an expressive language to extract information from HTML pages in a structured way, a mapping to export it as XML documents and some visual tools...

    Provided By University of Pennsylvania

  • White Papers // Apr 2010

    Income Inequality And Local Government In The United States, 1970-2000

    The income distribution in many developed countries widened dramatically from 1970 to 2000. Scholars speculate that inequality contributes to a host of social ills by weakening the public sector. In contrast, the authors find that growing income inequality is associated with an expansion in revenues and expenditures on a wide...

    Provided By University of Pennsylvania

  • White Papers // May 2009

    Pricing Guidance In Ad Sale Negotiations: The Printads Example

    The author considers negotiations between publishers and advertisers in a marketplace for ads. Motivated by Google's online Print Ads system which is such a marketplace, they focus on the role of the market runner in improving market efficiency. They notify the problem of pricing guidance where the market runner provides...

    Provided By University of Pennsylvania

  • White Papers // Jan 2011

    Characterizing Temporal SNR Variation in 802.11 Networks

    The analysis and design of wireless MAC protocols, coding schemes and transmission algorithms can significantly benefit from an understanding of the channel quality variation. The authors attempt to represent channel quality variation using a finite state birth-death Markov model. The authors outline a method to compute the parameters of the...

    Provided By University of Pennsylvania

  • White Papers // Sep 2009

    Direct Marketing On A Social Network

    Direct Marketing (DM) - sending promotional messages to individual customers - is increasingly used by marketers as a result of the explosive growth of customer databases. Most current methods to calculate optimal budgets for such DM campaigns consider customers in isolation and ignore word-of-mouth communication (WOM). When the customer base...

    Provided By University of Pennsylvania

  • White Papers // Apr 2010

    Influence Of Social Networks In Target Marketing

    Online social networks such as Facebook have shown a huge increase in the number of users. In this work, Facebook will be used as a dataset to see how social networks can be used to provide better target marketing strategies. In this paper, a Facebook application was built and products...

    Provided By University of Pennsylvania

  • White Papers // Jan 2011

    Multiplicative Updates for Large Margin Classifiers

    Various problems in nonnegative quadratic programming arise in the training of large margin classifiers. The authors derive multiplicative updates for these problems that converge monotonically to the desired solutions for hard and soft margin classifiers. The updates differ strikingly in form from other multiplicative updates used in machine learning. In...

    Provided By University of Pennsylvania

  • White Papers // Dec 2008

    Toward A New Risk Architecture: Welcome To Risk Management 2.0

    As recently as few years ago, few world leaders or thinkers would have pegged for the accelerating rhythm of large-scale catastrophes as one of the biggest economic challenges in the foreseeable future. But one of the hallmarks of this new century will be more and more such unthinkable events, previously...

    Provided By University of Pennsylvania

  • White Papers // Jul 2010

    Smudge Attacks on Smartphone Touch Screens

    Touch screens are an increasingly common feature on personal computing devices, especially smartphones, where size and user interface advantages accrue from consolidating multiple hardware components (keyboard, number pad, etc.) into a single software definable user interface. Oily residues, or smudges, on the touch screen surface, are one side effect of...

    Provided By University of Pennsylvania

  • White Papers // May 2010

    Preserving Module Privacy in Workflow Provenance

    The authors study the problem of providing workflow data provenance without revealing the functionality of any module. The authors develop a model that formalizes the notion of privacy of modules embedded in a workflow structure as a natural extension of privacy of standalone modules. The model shows that by hiding...

    Provided By University of Pennsylvania

  • White Papers // Jan 2011

    What Should Central Banks Do About Real Estate Prices?

    Many central banks use inflation targeting as the basis for their monetary policy. The underlying notion of this approach is that there are no long term benefits in terms of reduced unemployment from having inflation. The traditional view is that monetary policy should focus on controlling consumer price inflation. Asset...

    Provided By University of Pennsylvania

  • White Papers // Mar 2010

    African Financial Systems: A Review

    Africa is a continent made up of 53 countries. The continent is economically and culturally diverse, with different regional economic blocs. The financial systems in these countries are as diverse as the countries. Reviewing the financial systems of such a heterogeneous group of countries presents a challenge. Therefore, to make...

    Provided By University of Pennsylvania

  • White Papers // Oct 2010

    Dynamic Contract Trading in Spectrum Markets

    The authors address the question of optimal trading of bandwidth (service) contracts in wireless spectrum markets, for the primary spectrum providers. They propose a structured spectrum market and consider two basic types of spectrum contracts that can help attain desired flexibilities and tradeoffs in terms of service quality, spectrum usage...

    Provided By University of Pennsylvania

  • White Papers // Mar 2011

    Portfolio Optimization in Secondary Spectrum Markets

    In this paper, the authors address the Spectrum Portfolio Optimization (SPO) question in the context of secondary spectrum markets, where bandwidth (spectrum access rights) can be bought in the form of primary and secondary contracts. While a primary contract on a channel provides guaranteed access to the channel bandwidth (possibly...

    Provided By University of Pennsylvania

  • White Papers // Dec 2009

    Arrows for Secure Information Flow

    This paper presents an embedded security sub-language for enforcing information-flow policies in the standard Haskell programming language. The sub-language provides useful information-flow control mechanisms including dynamic security lattices, run-time code privileges and declassification all without modifying the base language. This design avoids the redundant work of producing new languages, lowers...

    Provided By University of Pennsylvania

  • White Papers // Apr 2009

    Updatable Security Views

    Security views are a flexible and effective mechanism for controlling access to confidential information. Rather than allowing untrusted users to access source data directly, they are instead provided with a restricted view, from which all confidential information has been removed. The program that generates the view effectively embodies a confidentiality...

    Provided By University of Pennsylvania

  • White Papers // Apr 2010

    Model Checking of Linearizability of Concurrent List Implementations

    Concurrent data structures with fine-grained synchronization are notoriously difficult to implement correctly. The difficulty of reasoning about these implementations does not stem from the number of variables or the program size, but rather from the large number of possible inter-leavings. These implementations are therefore prime candidates for model checking. The...

    Provided By University of Pennsylvania

  • White Papers // Jan 2011

    Languages of Nested Trees

    The authors study languages of nested trees-structures obtained by augmenting trees with sets of nested jump-edges. These graphs can naturally model branching behaviors of push-down programs, so that the problem of branching-time software model checking may be phrased as a membership question for such languages. They define finite-state automata accepting...

    Provided By University of Pennsylvania

  • White Papers // Jun 2009

    Algorithmic Analysis of Array-Accessing Programs

    For programs whose data variables range over boolean or nite domains, program verification is decidable, and this forms the basis of recent tools for software model checking. In this paper, the authors consider algorithmic verification of programs that use boolean variables, and in addition, access a single read-only array whose...

    Provided By University of Pennsylvania

  • White Papers // Oct 2010

    Expressiveness of Streaming String Transducers

    Streaming string transducers define (partial) functions from input strings to output strings. A streaming string transducer makes a single pass through the input string and uses a finite set of variables that range over strings from the output alphabet. At every step, the transducer processes an input symbol, and updates...

    Provided By University of Pennsylvania