cssi/SciSciGPT-SciSciNet huggingface dataset:
Lattice Point Enumeration on Block Reduced Bases

When analyzing lattice-based cryptosystems, we often need to solve the Shortest Vector Problem (SVP) in some lattice associated to the system under scrutiny. The go-to algorithms in practice to solve SVP are enumeration algorithms, which usually consist of a preprocessing step, followed by an exhaustive search. Obviously, the two steps offer a trade-off and should be balanced in their running time in order to minimize the overall complexity. In practice, the most common approach to control this trade-off is to use block reduction algorithms during the preprocessing. Despite the popularity of this approach, it lacks any well founded analysis and all practical approaches seem to use ad hoc parameters. This weakens our confidence in the cryptanalysis of the systems. In this work, we aim to shed light on at least one side of this trade-off and analyze the effect of block reduction on the exhaustive search. For this, we give asymptotic worst case bounds and present results from both experiments and simulation that show its average case behavior in practice.
Chemistry of 1,3-Ditungstacyclobutadienes

Publisher Summary This chapter discusses the chemistry of 1,3-ditungstacyclobutadienes. The metallacycles have enjoyed a pivotal position in recent advances in organometallic chemistry. The investigations by Whitesides and coworkers into the thermal decomposition of L 2 Pt (CH 2 ) n compounds, where n= 4,5, and 6, were among the first to place emphasis on the importance of steric accessibility for the β–hydrogen atom abstraction reaction. X–Ray crystallographic studies have determined M–M bond distances of 2.90, 2.54, and 2.55 A for Nb, W, and Re derivatives, respectively. Addition of alkynes to the tungsten d 1 —d 1 dimers (VI) might then yield, by a coupling of the μ-CsiMe 3 groups, a compound of type X. Allenes have been found to react with W 2 (μ–CSiMe 3 ) 2 -containing compounds to give, by C–C bond formation between the tertiary carbon of the allene and the bridging carbon of one of the μ-CSiMe 3 ligands, a bridging ligand, which is formally a π–allyl to one tungsten atom and a terminal alkylidene to the other tungsten. Isocyanide ligands and carbon monoxide react in hydrocarbon solvents with (Pr i O) 4 W 2 (μ-CSiMe 3 ) 2 to give the compounds of formula (Pr 1 O)(X=)W(μ-CsiMe 3 (μ-η 2 ,η 1 -CCSiMe 3 )W(OPr i ) 3 . The reaction pathway interconverting a dimetallatetrahedane and two alkylidyne metal fragments still remains to be established.
Weak convergence of stochastic neuronal models

The electrical behavior of neuronal membranes and the role of ion currents have been studied and understood since the landmark 1952 papers of Hodgkin and Huxley. The existence of ionic gates exhibiting stochastic behavior was confirmed over ten years ago with the development of the experimental patch-clamp technique, and the nature and structure of those ionic gates was illuminated dramatically in 1984 with the publication by Noda et al. [1984] of the complete amino acid chain comprising the sodium gating channel for the electric organ of electrophorus electricus. Despite all this experimental progress, and despite the wide interest in gaining a better understanding of the behavior of individual neurons and of systems of neurons, there has been little success in the efforts to develop stochastic mathematical models capable of reflecting and helping to predict neuronal activity. It is a goal of our research to develop such models in order to illuminate the connection between the microkinetic behavior of thousands of gating molecules scattered over the surface membrane of a single isolated neuron subject to a stream of excitatory and inhibitory impulses, and the macrokinetic behavior of that same neuron in generating and propagating action potentials and spike trains. We do not address the interesting questions of how networks of interconnected neurons behave.
Wide-band pulse-echo imaging with distributed apertures in multi-path environments

We derive a new image reconstruction method for distributed apertures operating in complex environments with additive non-stationary noise. Our method is capable of exploiting information that we might have about: multi-path scattering in the environment; statistics of the objects to be imaged; statistics of the additive non-stationary noise. The aperture elements are distributed spatially in an arbitrary fashion, and can be several hundred wavelengths apart. Furthermore, our method facilitates multiple transmit apertures which operate simultaneously, and is thus capable of handling a true multi-transmit-multi-receive scenario. The implementation of our reconstruction takes the form of a filter bank which is applied to the pulse-echo measurements. This processing can be performed independently on the measurements obtained from each receiving element. Our approach is therefore well suited for parallel implementation, and can be performed in a distributed manner in order to reduce the required communication bandwidth between each receiver and the location where the results are merged into the final image.
ASSESSING THE IMPACT OF INTELLECTUAL PROPERTY RIGHTS IN THE PLANT/SEED INDUSTRY

We develop a theoretical model of strategic firm behavior in seeking property rights given multiple property regimes. Our model suggests probability of the loss of trade secrets and revelations through patent applications does play a significant role in the choice of property rights by plant firms.
Non-malleable Condensers for Arbitrary Min-entropy, and Almost Optimal Protocols for Privacy Amplification

Recently, the problem of privacy amplification with an active adversary has received a lot of attention. Given a shared n-bit weak random source X with min-entropy k and a security parameter s, the main goal is to construct an explicit 2-round privacy amplification protocol that achieves entropy loss O(s). Dodis and Wichs [1] showed that optimal protocols can be achieved by constructing explicit non-malleable extractors. However, the best known explicit non-malleable extractor only achieves k = 0.49n [2] and evidence in [2] suggests that constructing explicit non-malleable extractors for smaller min-entropy may be hard. In an alternative approach, Li [3] introduced the notion of a non-malleable condenser and showed that explicit non-malleable condensers also give optimal privacy amplification protocols.
Constraint propagation for domain bounding in distributed task scheduling

The coordinated management of inter-dependent plans or schedules belonging to different agents is a complex, real-world problem arising in diverse domains such as disaster rescue, small-team reconnaissance, and security patrolling. The problem is inherently a distributed one; no single agent has a global view and must make local scheduling decisions through collaboration with other agents to ensure a high quality global schedule. A key step towards addressing this problem is to devise appropriate distributed representations. The Coordinators Task Analysis Environmental Modeling and Simulation (C_taems) language is a representation that was jointly designed by several multi-agent systems researchers explicitly for multi-agent task scheduling problems [1,2,3,4]. C_taems is an extremely challenging class of scheduling problem which is able to model the distributed aspects of the problem.
Preference-based graphic models for collaborative filtering

Collaborative filtering is a very useful general technique for exploiting the preference patterns of a group of users to predict the utility of items to a particular user. Previous research has studied several probabilistic graphic models for collaborative filtering with promising results. However, while these models have succeeded in capturing the similarity among users and items, none of them has considered the fact that users with similar interests in items can have very different rating patterns; some users tend to assign a higher rating to all items than other users. In this paper, we propose and study two new graphic models that address the distinction between user preferences and ratings. In one model, called the decoupled model, we introduce two different variables to decouple a user's preferences from hislher ratings. In the other, called the preference model, we model the orderings of items preferred by a user, rather than the user's numerical ratings of items. Empirical study over two datasets of movie ratings shows that, due to its appropriate modeling of the distinction between user preferences and ratings, the proposed decoupled model significantly outperforms all the five existing approaches that we compared with. The preference model, however, performs much worse than the decoupled model, suggesting that while explicit modeling of the underlying user preferences is very important for collaborative filtering, we can not afford ignoring the rating information completely.
CHAPTER 2 – Random Variables

Publisher Summary This chapter focuses on the random variables of the probability theory. The random variables of interest take on either a finite or a countable number of possible values. Such random variables are called discrete. However, there also exist random variables that take on a continuum of possible values. These are known as continuous random variables. The cumulative distribution function (CDF) of the random variable X is defined for any real number b, –∞<b < ∞, by F(b) = P{X ≤ b}. In words, F(b) denotes the probability that the random variable X takes on a value that will be less than or equal to b. Some properties of the CDF F are the following: (1) F(b) is a nondecreasing function of b, (2) = F(∞) = 1, and (3) = F(−∞) = 0. If X is a binomial random variable with parameters (n, p), then X has a binomial distribution with parameters (n, p). An important property of the Poisson random variable is that it may be used to approximate a binomial random variable when the binomial parameter n is large and p is small.
The expected perimeter in Eden and related growth processes

Following Richardson and using results of Kesten on first-passage percolation, we obtain an upper bound on the expected perimeter in an Eden growth process. Using results of the author from a problem in statistical mechanics, we show that the average perimeter of the lattice animals resulting from a very natural family of “growth histories” does not obey a similar bound.
Simulation of Terminal-Area Flight Management System Arrivals with Airborne Spacing

This paper describes a simulation which evaluated the feasibility and possible benefits in using decision support tools to support airborne spacing and merging for aircraft using flight management systems. It was found that spacing accuracy improved when spacing tasks were delegated to the equipped cockpits. The paper emphasizes the importance of having both decision support tools and spacing guidance exhibit consistently predictable performance, and that there needs to be coordination in merging traffic flows.
Cache Memory Energy Exploitation in VLIW Architectures

This is a comparative study of cache energy dissipations in Very Long Instruction Word (VLIW) and the classical superscalar microprocessors. While being architecturally different, the two types are analyzed in this work on the basis of similar underlying silicon fabrication platforms. The outcomes of the study reveal how energy is exploited in the cache system of the former which makes it more appealing to low-power applications with respect to the latter.
Development Economics and the International Development Association

Prevailing economic ideas -- and fashions -- about development have influenced the International Development Association (IDA) since its creation in 1960. The creation of the organization itself is the result of two contemporaneous facts: an urgent need to channel development finance to least-developed countries and an increasing pressure on World Bank management to directly address the issue of poverty in developing countries. Changing views, over time, have been a rationale -- and, at times, a justification -- for emphasizing poverty and social sectors; for providing grants to particular groups of countries; and for strategic choices and sectoral priorities. IDA has been influential in development debates and been an advocate for specific views about development policy. This paper gives an overview of these views and documents how they have shaped the activities of the organization since its creation. After a brief review of development thinking and of the organization of research at the World Bank, the paper documents the shifts that have taken place in country allocations and in sector emphasis in IDA over the past 50 years and highlights the strategic themes that have guided its development agenda: toward increasing country selectivity; from projects to programs; from conditionality to country ownership of reforms; and from input-based to results-based performance.
Detecting anomalies in cargo using graph properties

The ability to mine relational data has become important in several domains (e.g., counter-terrorism), and a graph-based representation of this data has proven useful in detecting various relational, structural patterns [1]. Here, we analyze the use of graph properties as a method for uncovering anomalies in data represented as a graph.
An introduction to toothpaste - its purpose, history and ingredients

Toothpaste is a paste or gel to be used with a toothbrush to maintain and improve oral health and aesthetics. Since their introduction several thousand years ago, toothpaste formulations have evolved considerably - from suspensions of crushed egg shells or ashes to complex formulations with often more than 20 ingredients. Among these can be compounds to combat dental caries, gum disease, malodor, calculus, erosion and dentin hypersensitivity. Furthermore, toothpastes contain abrasives to clean and whiten teeth, flavors for the purpose of breath freshening and dyes for better visual appeal. Effective toothpastes are those that are formulated for maximum bioavailability of their actives. This, however, can be challenging as compromises will have to be made when several different actives are formulated in one phase. Toothpaste development is by no means complete as many challenges and especially the poor oral substantivity of most active ingredients are yet to overcome.
Capitalization of the Property-Liability Insurance Industry: Overview

The 1990s witnessed an unprecedented decline in leverage ratios in the United States property-liability insurance industry. The premiums-to-surplus ratio, the most commonly used leverage ratio in the industry, fell from its historical average of 2.0 to less than 1.0 by the end of 2000; and the industry-wide capital-to-asset ratio increased from an historical average of about 25% to 35%. The international reinsurance industry also experienced significant capital increases and leverage declines during the 1990s (Cummins and Weiss, 2000).1 These unusual trends raised widespread concerns that the property-liability insurance industry had become over-capitalized (The Economist, 1999; Bowers, 2001; Seifert, 2001). To investigate the growth in capitalization and its potential causes, the Conference on Capitalization in the Property-Liability Insurance Industry was held at the Wharton School in September 2000 under the joint sponsorship of the Wharton Financial Institutions Center and AON. Selected papers from the conference comprise this issue of the Journal of Financial Services Research (JFSR).
Rapid Detection of Gram-Negative Bacteriuria by Use of the Limulus Endotoxin Assay

The Limulus in vitro endotoxin assay was evaluated as a possible method for the prompt detection of significant gram-negative bacteriuria in children. This assay is capable of detecting endotoxin associated with intact cell walls of viable gram-negative bacteria as well as free endotoxin. Quantitative results are obtained following a 1-h incubation of Limulus lysate and 10-fold dilutions of otherwise untreated urine. A standard curve of Limulus activity and viable cell counts of Escherichia coli and Klebsiella pneumoniae in urine demonstrated that a positive Limulus reaction at a dilution of 1:100 or 1:1,000 indicated a colony count of at least 100,000 bacteria/ml. A positive Limulus reaction only from undiluted urine or at a dilution of 1:10 indicated less than 100,000 cells/ml. These experimental observations were confirmed by comparing the Limulus test with quantitative plate counts on 209 urine specimens from a mixed pediatric population. These results indicate that the Limulus assay is a simple, accurate method for rapid presumptive detection of gram-negative bacteriuria in patients where an immediate diagnosis is needed. This test would also seem promising for screening large patient populations for bacteriuria or for monitoring the effectiveness of treatment of urinary tract infections.
The cytogenetics of Oenothera.

Publisher Summary This chapter discusses Euoenothera (Onagra) as found in North America or as represented by European derivatives of North American origin. Oenothera comprises fifteen subgenera, of which only the largest has been extensively studied cytogenetically. The genus is native to the western hemisphere but has been extensively introduced into other areas of the world. The first reference to Oenothera in Europe is that of Prosperus Alpinus of Padua. It has become widely distributed throughout Europe where it constitutes an important element in the flora. To summarize this situation, most Oenotheras are “complex-heterozygotes.” Each race has two different complexes or permanent genomes. This results from the inclusion of all genes within a single linkage group for which the plant is heterozygous, the presence of one or more lethals in each genome and self pollination. Hybrids derived from the crossing of true-breeding complex-heterozygotes have two or more linkage groups. The prevalence of translocations that have brought about the widespread occurrence of structural hybridity naturally tends to focus interest upon chromosome structure in Oenothera. One of the striking features of Oenothera genetics is the relative paucity of detectable crossing-over. The genes that show crossing-over in the races lie in the transitional zone between the regularly pairing end segments and the proximal segments in which the genes that differentiate the complexes lie.
Retail Pricing Behavior for Perishable Produce Products in the US with Implications for Farmer Welfare

The typical model of retail pricing for produce products assumes retailers set price equal to the farm price plus a certain markup. However, observations from scanner data indicate a large degree of price dispersion in the grocery retailing market. In addition to markup pricing behavior, we document three alternative leading pricing patterns: fixed (constant) pricing, periodic sale, and high-low pricing. Retail price variations under these alternative pricing regimes in general have little correlation with the farm price. How do retailers’ alternative pricing behaviors affect farmers’ welfare? Using markup pricing as the baseline case, we parameterize the model to reflect a prototypical fresh produce market and carry out a series of simulations under different pricing regimes. Our study shows that if harvest cost is sufficiently low, retail prices adjusting only partially, or not at all, to supply shocks tends to diminish farm income and exacerbate farm price volatility relative to the baseline case. However, we also find that if harvest cost is sufficiently large and the harvest-cost constraint places a lower bound on the farm price, increased farm price volatility induced by retailers’ alternative pricing strategies may result in higher farm income, compared to markup pricing. Our study is the first to evaluate the welfare implications for producers of the diversified pricing strategies that retailers utilize in practice and the resulting attenuation of the relationship between prices at retail and at the farm gate.
Lightweight simulation of air traffic control using simple temporal networks

Flight simulators are becoming more sophisticated and realistic, and the requirements of those using them are becoming more demanding. Air traffic control simulation for such simulators is now approaching the real problem of air traffic control, where several aircraft need to be scheduled for safe approach and landing or for safe passage through the air space that an air traffic controller is responsible for. Also, the computational resources available to dedicate to air traffic control simulation are sparse, given that most simulations focus on a realistic graphical user interface and aircraft physics modeling. We provide a formulation of the air traffic control problem and a solver for this problem that makes use of temporal constraint networks and simple geometric reasoning. We provide results showing that this approach is practical for realistic simulated problems.
The Nondeterministic Constraint Logic Model of Computation: Reductions and Applications

We present a nondeterministic model of computation based on reversing edge directions in weighted directed graphs with minimum in-flow constraints on vertices. Deciding whether this simple graph model can be manipulated in order to reverse the direction of a particular edge is shown to be PSPACE-complete by a reduction from Quantified Boolean Formulas. We prove this result in a variety of special cases including planar graphs and highly restrictedv ertex configurations, some of which correspond to a kind of passive constraint logic. Our framework is inspired by (and indeed a generalization of) the "Generalized Rush Hour Logic" developed by Flake and Baum [2].We illustrate the importance of our model of computation by giving simple reductions to show that multiple motion-planning problems are PSPACE-hard. Our main result along these lines is that classic unrestricted sliding-block puzzles are PSPACE-hard, even if the pieces are restrictedto be all dominoes (1×2 blocks) andthe goal is simply to move a particular piece. No prior complexity results were known about these puzzles. This result can be seen as a strengthening of the existing result that the restricted Rush Hour? puzzles are PSPACE-complete [2], of which we also give a simpler proof. Finally, we strengthen the existing result that the pushing-blocks puzzle Sokoban is PSPACE-complete [1], by showing that it is PSPACE-complete even if no barriers are allowed.
Universal factorizations of quasiperiodic functions

Chirped sinosoids and interferometric phase plots are functions that are not periodic, but are the composition of a smooth function and a periodic function. These functions factor into a pair of maps: from their domain to a circle, and from a circle to their codomain. One can easily imagine replacing the circle with other phase spaces to obtain a general quasiperiodic function. This paper shows that under appropriate restrictions, each quasiperiodic function has a unique universal factorization. Quasiperiodic functions can therefore be classified based on their phase space and the phase function mapping into it.
Effects of Niobium Addition on Microstructural and Electrical Properties of Lead Zirconate Titanate Solid Solution (PZT 95/5)

The impacts of small niobium additions to processing, microstructure, and electrical properties in the Zr-rich lead zirconate titanate ceramics (PZT 95/5) were investigated. The influence of niobium content on dielectricresponses and the characteristics of ferroelectric behaviors, as well as the relative phase stability and the hydrostatic pressure induced ferroelectric-to-antiferroelectric phase transformation are reported. Results indicate that increasing the niobium concentration in the solid solutions enhances densification, refines the microstructure, decreases dielectric constant and spontaneous polarization, and stabilizes the ferroelectric phase. The stabilization of ferroelectric phase with respect to the antiferroelectric phase near PZT 95/5 composition dramatically increases the pressure required for the ferroelectric-to-antiferroelectric phase transformation. These observations were correlated to the creation of A-site vacancies and a slight modification of the crystal structure. The importance of these composition-property relationships on device application will be presented.
Dynamic clustering of web search results

A problem in Web searches is how to help users quickly find useful links from a long list of returned URLs. Document clustering provides an approach to organize retrieval results by clustering documents into meaningful groups. Because a word in a document is naturally correlated with neighboring words, document clustering often uses phrases rather than individual words in determining clusters. We have designed a system to cluster Web search results based on phrases that contain one or more search keywords. We show that, rather than clustering based on whole documents, clustering based on phrases containing search keywords often gives more accurate and informative clusters. Algorithms and experimental results are discussed.
In School or at Work? Evidence from a Crisis

This paper makes use of the income variability generated by the macroeconomic crisis of 2001/2002 to examine schooling outcomes in Argentina. The effect of this macroeconomic swing is examined with a focus on whether the income or substitution effect dominates in the decision-making of young people. It is demonstrated that the probability of being in school was 6.5–10 percentage points higher in May 2002 than in 2001 for 15–18-year-olds. This is probably the largest (positive) effect found in the developing country literature so far and is comparable to the effect of a 10% increase in household income. For 19–25-year-olds, the probability is between 2 and 6 percentage points higher. Results are robust to a wide range of controls and specification checks. Difference-in-difference panel estimation corroborates these findings and shows that the increase in schooling seems to be driven by a decrease in school exits during the crisis.
A LIDAR‐DERIVED EVALUATION OF WATERSHED‐SCALE LARGE WOODY DEBRIS SOURCES AND RECRUITMENT MECHANISMS: COASTAL MAINE, USA

In-channel large woody debris (LWD) promotes quality aquatic habitat through sediment sorting, pool scouring and in-stream nutrient retention and transport. LWD recruitment occurs by numerous ecological and geomorphic mechanisms including channel migration, mass wasting and natural tree fall, yet LWD sourcing on the watershed scale remains poorly constrained. We developed a rapid and spatially extensive method for using light detection and ranging data to do the following: (i) estimate tree height and recruitable tree abundance throughout a watershed; (ii) determine the likelihood for the stream to recruit channel-spanning trees at reach scales and assess whether mass wasting or channel migration is a dominant recruitment mechanism; and (iii) understand the contemporary and future distribution of LWD at a watershed scale. We utilized this method on the 78-km-long Narraguagus River in coastal Maine and found that potential channel-spanning LWD composes approximately 6% of the valley area over the course of the river and is concentrated in spatially discrete reaches along the stream, with 5 km of the river valley accounting for 50% of the total potential LWD found in the system. We also determined that 83% of all potential LWD is located on valley sides, as opposed to 17% on floodplain and terrace surfaces. Approximately 3% of channel-spanning vegetation along the river is located within one channel width of the stream. By examining topographic and morphologic variables (valley width, channel sinuosity, valley-side slope) over the length of the stream, we evaluated the dominant recruitment processes along the river and often found a spatial disconnect between the location of potential channel-spanning LWD and recruitment mechanisms, which likely explains the low levels of LWD currently found in the system. This rapid method for identification of LWD sources is extendable to other basins and may prove valuable in locating future restoration projects aimed at increasing habitat quality through wood additions. Copyright © 2011 John Wiley & Sons, Ltd.
Measurement of behind-armor debris using cylindrical holograms

Cylindrical holography has been utilized to capture 180 degree(s) field of view of high speed ballistic events. In this paper, we detail the methodology, design, and experimental results for a cylindrical hologram system that captures the fragment fields behind a penetrated armor plate. It is critical to use the wrap-around approach for proper test evaluation because of the possibility of large armor chunks blocking other fragments. An 18 ns pulse width, 3 Joule ruby laser is used as the illumination source for these 45.7 cm diameter holograms. For this application, the primary challenge has been the mitigation of the large flash caused by the projectile/target interaction. Several flash reduction techniques are discussed including narrow- band and neutral density filtering. Experimental results for this ongoing effort are presented.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Dictionary-learning-based reconstruction method for electron tomography.

Summary Electron tomography usually suffers from so-called “missing wedge” artifacts caused by limited tilt angle range. An equally sloped tomography (EST) acquisition scheme (which should be called the linogram sampling scheme) was recently applied to achieve 2.4-angstrom resolution. On the other hand, a compressive sensing inspired reconstruction algorithm, known as adaptive dictionary based statistical iterative reconstruction (ADSIR), has been reported for X-ray computed tomography. In this paper, we evaluate the EST, ADSIR, and an ordered-subset simultaneous algebraic reconstruction technique (OS-SART), and compare the ES and equally angled (EA) data acquisition modes. Our results show that OS-SART is comparable to EST, and the ADSIR outperforms EST and OS-SART. Furthermore, the equally sloped projection data acquisition mode has no advantage over the conventional equally angled mode in this context. SCANNING 36:377–383, 2014. © 2013 Wiley Periodicals, Inc.
Factors Determining Exchange Rates: The Roles of Relative Price Levels, Balances of Payments, Interest Rates and Risk

his paper focuses on an accounting framework that is useful for distinguishing between the effects on exchange rates of four separate factors: relative price levels, balances of payments, interest rates and risk. The framework rests upon an approximate identity, which is transformed into a behavioural model of exchange rates. The model is then applied in an attempt to explain the month-to-month behaviour of the US dollar versus the Deutsche Mark during the 1975-79 period.
Real Business Cycles and Automatic Stabilizers

Empirical evidence documents a discernible negative relationship between government size, as measured by income tax rates and the output share of government purchases, and the magnitude of macroeconomic fluctuations in OECD countries since 1960. This implies that both taxes and public spending seem to be effectively working as "automatic stabilizers". In this paper, we examine the effects of income taxes and government consumption on output variability in several versions of infinite-horizon representative agent (real business cycle, RBC) models with equilibrium determinacy and exogenous productivity shocks. In particular, we allow for either one or two sectors of production, either a constant or increasing returns-to-scale technology, and two different formulations of the household utility function. We also incorporate debt-financed borrowing by the government into the analysis. As Gali (1994, European Economic Review) has shown, in the one-sector RBC model with constant returns in production, utility logarithmic in both consumption and leisure, and government borrowing, income taxes are destabilizing and government purchases are stabilizing. However, we find the opposite results when the household utility is logarithmic in consumption and convex in hours worked. That is, income taxes are now stabilizing and government purchases are destabilizing. Moreover, these results are robust to allowing for increasing returns-to-scale and/or a balanced-budget rule. In sum, our analysis illustrates that in the context of RBC models, the stabilization effects of fiscal policy depend crucially on how hours worked enter the household utility function and the associated labor-market behavior.
Toward Architecture Evaluation through Ontology-Based Requirements-Level Scenarios

We describe an approach for evaluating whether a candidate architecture dependably satisfies stakeholder requirements expressed in requirements-level scenarios. We map scenarios to architectural elements through an ontology of requirements-level event classes and domain entities. The scenarios express both functional requirements and quality attributes of the system; for quality attributes, the scenarios either operationalize the quality or show how the quality can be verified. Our approach provides a connection between requirements a stakeholder can understand directly, and architectures developed to satisfy those requirements. The requirements-level ontology simplifies the mapping, acts as the focus for maintaining the mapping as both scenarios and architecture evolve, and provides a foundation for evaluating scenarios and architecture individually and jointly. In this paper, we focus on the mapping through event classes and demonstrate our approach with two examples.
The intermingled history of occupational therapy and anatomical education: A retrospective exploration

Few research articles have addressed the anatomical needs of entry-level occupational therapy students. Given this paucity of empirical evidence, there is a lack of knowledge regarding anatomical education in occupational therapy. This article will primarily serve as a retrospective look at the inclusion of anatomical education in the occupational therapy curriculum. Focusing on the historical inclusion is the first step to address the gap in existing knowledge. Examining the history of anatomy in occupational therapy provides an educational context for curricular developments and helps current anatomical educators understand the evolution of occupational therapy as a profession. Exploring the educational history also offers anatomy educators an identity, as significant contributors, in the training and preparedness of entry-level professionals while focusing on the ideals of occupational therapy. However, there is a critical need for empirical evidence of best teaching practices in occupational therapy and anatomical education. This manuscript provides a foundation and a starting point for further investigation into the anatomical competencies for entry-level occupational therapists.
Race, Segregation, and Postal Employment: New Evidence on Spatial Mismatch

Abstract The spatial mismatch hypothesis posits that employment decentralization isolated urban blacks from work opportunities. This paper focuses on one large employer that has remained in the central city over the twentieth century—the U.S. Postal Service. We find that blacks substitute towards postal work as other employment opportunities leave the city circa 1960. The response is particularly strong in segregated areas, where black neighborhoods are clustered near the central business district. Furthermore, this pattern only holds for non-mail carriers, many of whom work in central processing facilities. More recently, the relationship between black postal employment and segregation has declined, suggesting that spatial mismatch has become less important over time.
Intellectual property rights and the TRIPS agreement : an overview of ethical problems and some proposed solutions

The Agreement on Trade-Related Aspects of Intellectual Property Rights negotiated in 1986 under the auspices of the General Agreement on Tariffs and Trade, the institutional predecessor of the World Trade Organization, incorporated substantial and uniform protections of intellectual property rights into the international trade system. A large body of contemporary academic literature suggests that intellectual property rights on socially valuable goods such as essential medicines give rise to a number of ethical problems. This review paper seeks to give an overview of these problems. Moreover, it offers an outline and discussion of a number of proposals as to how these problems might be alleviated. The paper is primarily descriptive in character. This means that although a personal perspective is sometimes offered, the primary ambition of the paper is not to argue for, and defend, a particular solution to the issues discussed. The aim is rather to highlight, explain and put into perspective a number of important arguments in the debate on the ethical nature of intellectual property rights so that policy-makers and other stakeholders are relatively well-equipped to make up their own mind on the issue.
Resilient information infrastructures

Purpose – Disasters of catastrophic scope and scale have occurred more frequently in recent years. Governmental and non-governmental response management has struggled, and affected communities have severely suffered during extreme events. Colossal damage and loss of lives have been inflicted, and the recovery efforts require extended periods of time. In post hoc analyses, actionable information has been found a critical resource requiring resilient information infrastructures (RIIs) that do not break down even under extreme duress. RIIs encompass both tangible and less tangible (for example, social) elements. The purpose of this paper is to pave the way for empirical research on the subject and to conceptually develop a framework for the analysis of information infrastructures and their resiliency, when impacted by catastrophic incidents (also known as extreme events). Design/methodology/approach – The authors review the literatures of disaster research and related fields. They synthesize the literatures ...
Alternative Surrogates for Video Objects in a Digital Library: Users' Perspectives on Their Relative Usability

In a digital environment, it is feasible to integrate multimedia materials into a library collection with ease. However, it seems likely that nontextual surrogates for multimedia objects, e.g., videos, could effectively augment textual representations of those objects. In this study, five video surrogates were evaluated in relation to their usefulness and usability in accomplishing specific tasks. The surrogates (storyboards with text or audio keywords, slide shows with text or audio keywords, fast forward) were created for each of seven video segments. Ten participants, all of whom watch videos at least monthly and search for videos at least occasionally, viewed the surrogates for seven video segments and provided comments about the strengths and weaknesses of each. In addition, they performed a series of tasks (gist determination, object recognition, action recognition, and visual gist determination) with three surrogates selected from those available. No surrogate was universally judged "best," but the fast forward surrogate garnered the most support, particularly from experienced video users. The participants expressed their understanding of video gist as composed of three components: topicality, the story of the video, and the visual gist of the video. They identified several real-world tasks for which they regularly use video collections. The viewing compaction rates used in these surrogates supported adequate performance, but users expressed a desire for more control over surrogate speed and sequencing. Further development of these surrogates is warranted by these results, as well as the development of mechanisms for surrogate display.
The route to chaos for the Kuramoto-Sivashinsky equation

We present the results of extensive numerical experiments of the spatially periodic initial value problem for the Kuramoto-Sivashinsky equation. Our concern is with the asymptotic nonlinear dynamics as the dissipation parameter decreases and spatio-temporal chaos sets in. To this end the initial condition is taken to be the same for all numerical experiments (a single sine wave is used) and the large time evolution of the system is followed numerically. Numerous computations were performed to establish the existence of windows, in parameter space, in which the solution has the following characteristics as the viscosity is decreased: a steady fully modal attractor to a steady bimodal attractor to another steady fully modal attractor to a steady trimodal attractor to a periodic (in time) attractor, to another steady fully modal attractor, to another time-periodic attractor, to a steady tetramodal attractor, to another time-periodic attractor having a full sequence of period-doublings (in the parameter space) to chaos. Numerous solutions are presented which provide conclusive evidence of the period-doubling cascades which precede chaos for this infinite-dimensional dynamical system. These results permit a computation of the lengths of subwindows which in turn provide an estimate for their successive ratios as the cascade develops. A calculation based on the numerical results is also presented to show that the period-doubling sequences found here for the Kuramoto-Sivashinsky equation, are in complete agreement with Feigenbaum's universal constant of 4.669201609.... Some preliminary work shows several other windows following the first chaotic one including periodic, chaotic, and a steady octamodal window; however, the windows shrink significantly in size to enable concrete quantitative conclusions to be made.
Prediction strategies without loss

Consider a sequence of bits where we are trying to predict the next bit from the previous bits. Assume we are allowed to say 'predict 0' or 'predict 1', and our payoff is +1 if the prediction is correct and –1 otherwise. We will say that at each point in time the loss of an algorithm is the number of wrong predictions minus the number of right predictions so far. In this paper we are interested in algorithms that have essentially zero (expected) loss over any string at any point in time and yet have small regret with respect to always predicting 0 or always predicting 1. For a sequence of length T our algorithm has regret 14∊T and loss 2√T e−∊∊T in expectation for all strings. We show that the tradeoff between loss and regret is optimal up to constant factors. Our techniques extend to the general setting of N experts, where the related problem of trading off regret to the best expert for regret to the 'special' expert has been studied by Even-Dar et al. (COLT'07). We obtain essentially zero loss with respect to the special expert and optimal loss/regret tradeoff, improving upon the results of Even-Dar et al and settling the main question left open in their paper. The strong loss bounds of the algorithm have some surprising consequences. First, we obtain a parameter free algorithm for the experts problem that has optimal regret bounds with respect to k-shifting optima, i.e. bounds with respect to the optimum that is allowed to change arms multiple times. Moreover, for any window of size n the regret of our algorithm to any expert never exceeds O(√n(log N + log T)), where N is the number of experts and T is the time horizon, while maintaining the essentially zero loss property.
Topological interference management with just retransmission: What are the “Best” topologies?

We study the problem of interference management in fast fading wireless networks, in which the transmitters are only aware of network topology. We consider a class of retransmission-based schemes, where transmitters in the network are only allowed to resend their symbols in order to assist with the neutralization of interference at the receivers. We introduce a necessary and sufficient condition on the network topology, under which half symmetric degrees-of-freedom (DoF) is achievable through the considered retransmission-based schemes. This corresponds to the “best” topologies since half symmetric DoF is the highest possible value for the symmetric DoF in the presence of interference. We show that when the condition is satisfied, there always exists a set of carefully chosen transmitters in the network, such that by retransmission of their symbols at an appropriate time slot, we can neutralize all the interfering signals at the receivers. Quite surprisingly, we also show that for any given network topology, if we cannot achieve half symmetric DoF by retransmission-based schemes, then there does not exist any linear scheme that can do so. We also consider a practical network scenario that models cell edge users in a heterogeneous network, and show that the characterized condition on the network topology occurs frequently. Furthermore, we numerically evaluate the achievable rates of the DoF-optimal retransmission-based scheme in such network scenario, and show that its throughput gain is not restricted to the asymptotic DoF analysis.
Optimal topology control with physical power flow constraints and N-1 contingency criterion

In this paper, a novel solution method is proposed for the optimal topology control problem in AC framework with N-1 reliability. The resultant new topology of the proposed method is guaranteed to yield a better objective function value than the global solution of the problem with the original topology. In order to prove our statement, semi-definite programming relaxation is formulated to find a lower bound to the objective function value of the problem. The proposed method is favorable for parallelization to increase the computational efficiency, and the parallel computing flowchart is presented. Computational time of the algorithm for IEEE test cases is reported. An in-house power market simulator is developed to simulate a market environment complete with optimal topology control mechanism. Simulations held by participating human subjects are analyzed under the subtitles of the total operating cost, real power losses, and locational marginal price (LMP) variance. A simple example is illustrated to show that the resultant network topology may increase the real power losses while still providing a lower operating system cost than that of the original topology.