Showing papers by "Worcester Polytechnic Institute published in 2011"

Direct Numerical Simulations of Gas-Liquid Multiphase Flows

Abstract: Direct numerical simulations of bubbly flows are reviewed and recent progress is discussed. Simulations, of homogeneous bubble distribution in fully periodic domains at relatively low Reynolds numbers have already yielded considerable insight into the dynamics of such flows. Many aspects of the evolution converge rapidly with the size of the systems and results for the rise velocity, the velocity fluctuations, as well as the average relative orientation of bubble pairs have been obtained. The challenge now is to examine bubbles at higher Reynolds numbers, bubbles in channels and confined geometry, and bubble interactions with turbulent flows. We briefly review numerical methods used for direct numerical simulations of multiphase flows, with a particular emphasis on methods that use the so-called "one-field" formulation of the governing equations, and then discuss studies of bubbles in periodic domains, along with recent work on wobbly bubbles, bubbles in laminar and turbulent channel flows, and bubble formation in boiling.

Data Envelopment Analysis: History, Models, and Interpretations

Abstract: In about 30 years, Data Envelopment Analysis (DEA) has grown into a powerful quantitative, analytical tool for measuring and evaluating the performance. DEA has been successfully applied to a host of many different types of entities engaged in a wide variety of activities in many contexts worldwide. This chapter discusses the basic DEA models and some of their extensions.

Engineering education and the development of expertise

Abstract: Contributors Michael Alley, The Pennsylvania State University; Cindy Atman, University of Washington; David DiBiasio, Worcester Polytechnic Institute; Cindy Finelli, University of Michigan; Heidi Diefes-Dux, Purdue University; Anette Kolmos, Aalborg University; Donna Riley, Smith College; Sheri Sheppard, Stanford University; Maryellen Weimer, The Pennsylvania State University; Ken Yasuhara, University of Washington Background Although engineering education has evolved in ways that improve the readiness of graduates to meet the challenges of the twenty-first century, national and international organizations continue to call for change. Future changes in engineering education should be guided by research on expertise and the learning processes that support its development. Purpose The goals of this paper are: to relate key findings from studies of the development of expertise to engineering education, to summarize instructional practices that are consistent with these findings, to provide examples of learning experiences that are consistent with these instructional practices, and finally, to identify challenges to implementing such learning experiences in engineering programs. Scope/Method The research synthesized for this article includes that on the development of expertise, students' approaches to learning, students' responses to instructional practices, and the role of motivation in learning. In addition, literature on the dominant teaching and learning practices in engineering education is used to frame some of the challenges to implementing alternative approaches to learning. Conclusion Current understanding of expertise, and the learning processes that develop it, indicates that engineering education should encompass a set of learning experiences that allow students to construct deep conceptual knowledge, to develop the ability to apply key technical and professional skills fluently, and to engage in a number of authentic engineering projects. Engineering curricula and teaching methods are often not well aligned with these goals. Curriculum-level instructional design processes should be used to design and implement changes that will improve alignment.

The Economics of Director Heterogeneity

Abstract: We investigate the potential costs and benefits of firms constituting a heterogeneous pool of directors relative to more homogeneous boards. We measure director heterogeneity along six separate dimensions and divide board heterogeneity into occupational and social components. Our empirical analysis indicates that corporate complexity and managerial control exhibit significant influence on board heterogeneity. Using the heterogeneity of the county population of the firm’s headquarters as an instrument, we also find that investors place valuation premiums on heterogeneous boards in complex firms but discount heterogeneity in less complex firms. Overall, our analysis indicates greater heterogeneity may not necessarily improve board efficacy. Government agencies, shareholder groups, and social activists frequently advocate and call for greater heterogeneity among directors on corporate boards. Proponents of greater board heterogeneity argue that managers and firms benefit from directors bringing diverse social and occupational viewpoints to the boardroom. Large international firms such as PepsiCo and Aon Corp indicate social heterogeneity among directors proves helpful in developing new products and strategies. 1 A 1995 Catalyst (2004) survey found that Fortune 500 chief executive officers (CEOs) considered director heterogeneity an important “bottom-line” or profitability consideration. Activist investor groups such as Catalyst, ICCR, and TIAA-CREF argue that homogeneous boards composed of the CEO’s own peers may be less effective advisors and monitors. In early 2009, the California Public Employees Retirement System issued a report indicating that board diversity leads to greater shareholder returns and firm profitability. Yet, the push for less uniformity in the boardroom may be driven by social or ethical reasons rather than firm profitability (Agrawal and Knoeber, 2001). Farrell and Hersch (2005) examine gender heterogeneity and find women board members have no influence on firm performance. They argue that firms simply include members of minority groups to build a public image of inclusiveness or tokenism. In contrast, Adams and Ferreira (2009) state that gender diversity has a positive and significant impact on board effectiveness. In a general analysis using a large survey of 30,000 interviews from the United States, Putnam (2007) reports that heterogeneity among individuals decreases cooperation, impedes communication, and leads to social loafing. Board

Privacy-preserving multi-keyword ranked search over encrypted cloud data

Abstract: With the advent of cloud computing, data owners are motivated to outsource their complex data management systems from local sites to the commercial public cloud for great flexibility and economic savings. But for protecting data privacy, sensitive data has to be encrypted before outsourcing, which obsoletes traditional data utilization based on plaintext keyword search. Thus, enabling an encrypted cloud data search service is of paramount importance. Considering the large number of data users and documents in the cloud, it is necessary to allow multiple keywords in the search request and return documents in the order of their relevance to these keywords. Related works on searchable encryption focus on single keyword search or Boolean keyword search, and rarely sort the search results. In this paper, for the first time, we define and solve the challenging problem of privacy-preserving multi-keyword ranked search over encrypted cloud data (MRSE).We establish a set of strict privacy requirements for such a secure cloud data utilization system. Among various multi-keyword semantics, we choose the efficient similarity measure of “coordinate matching”, i.e., as many matches as possible, to capture the relevance of data documents to the search query. We further use “inner product similarity” to quantitatively evaluate such similarity measure. We first propose a basic idea for the MRSE based on secure inner product computation, and then give two significantly improved MRSE schemes to achieve various stringent privacy requirements in two different threat models. Thorough analysis investigating privacy and efficiency guarantees of proposed schemes is given. Experiments on the real-world dataset further show proposed schemes indeed introduce low overhead on computation and communication.

Authorized Private Keyword Search over Encrypted Data in Cloud Computing

Abstract: In cloud computing, clients usually outsource their data to the cloud storage servers to reduce the management costs. While those data may contain sensitive personal information, the cloud servers cannot be fully trusted in protecting them. Encryption is a promising way to protect the confidentiality of the outsourced data, but it also introduces much difficulty to performing effective searches over encrypted information. Most existing works do not support efficient searches with complex query conditions, and care needs to be taken when using them because of the potential privacy leakages about the data owners to the data users or the cloud server. In this paper, using on line Personal Health Record (PHR) as a case study, we first show the necessity of search capability authorization that reduces the privacy exposure resulting from the search results, and establish a scalable framework for Authorized Private Keyword Search (APKS) over encrypted cloud data. We then propose two novel solutions for APKS based on a recent cryptographic primitive, Hierarchical Predicate Encryption (HPE). Our solutions enable efficient multi-dimensional keyword searches with range query, allow delegation and revocation of search capabilities. Moreover, we enhance the query privacy which hides users' query keywords against the server. We implement our scheme on a modern workstation, and experimental results demonstrate its suitability for practical usage.

A time-discrete model for dynamic fracture based on crack regularization

Abstract: We propose a discrete time model for dynamic fracture based on crack regularization. The advantages of our approach are threefold: first, our regularization of the crack set has been rigorously shown to converge to the correct sharp-interface energy Ambrosio and Tortorelli (Comm. Pure Appl. Math., 43(8): 999–1036 (1990); Boll. Un. Mat. Ital. B (7), 6(1):105–123, 1992); second, our condition for crack growth, based on Griffith’s criterion, matches that of quasi-static settings Bourdin (Interfaces Free Bound 9(3): 411–430, 2007) where Griffith originally stated his criterion; third, solutions to our model converge, as the time-step tends to zero, to solutions of the correct continuous time model Larsen (Math Models Methods Appl Sci 20:1021–1048, 2010). Furthermore, in implementing this model, we naturally recover several features, such as the elastic wave speed as an upper bound on crack speed, and crack branching for sufficiently rapid boundary displacements. We conclude by comparing our approach to so-called “phase-field” ones. In particular, we explain why phase-field approaches are good for approximating free boundaries, but not the free discontinuity sets that model fracture.

Legal Expertise on Corporate Audit Committees and Financial Reporting Quality

Abstract: Recent trends in corporate board composition indicate an increase in the appointment of directors with legal expertise. Using two financial reporting quality measures, accruals quality and discretionary accruals, we find—for a sample of Russell 1000 firms in 2003 and 2005—that the presence (and proportion) of directors with legal backgrounds on the audit committee is associated with higher financial reporting quality. These results obtain after controlling for accounting expertise on audit committees. Also, supplementary tests indicate a positive association between changes in legal expertise and changes in financial reporting quality, suggesting that legal expertise serves as a monitor rather than as a signal of financial reporting quality. Further, the two forms of expertise interact —i.e., the presence of directors with both forms of expertise enhances financial reporting quality, beyond the contribution of the individual forms of expertise. Additional tests suggest that the positive effects ...

Jaql: a scripting language for large scale semistructured data analysis

Abstract: This paper describes Jaql, a declarative scripting language for analyzing large semistructured datasets in parallel using Hadoop's MapReduce framework Jaql is currently used in IBM's InfoSphere BigInsights [5] and Cognos Consumer Insight [9] products Jaql's design features are: (1) a flexible data model, (2) reusability, (3) varying levels of abstraction, and (4) scalability Jaql's data model is inspired by JSON and can be used to represent datasets that vary from flat, relational tables to collections of semistructured documents A Jaql script can start without any schema and evolve over time from a partial to a rigid schema Reusability is provided through the use of higher-order functions and by packaging related functions into modules Most Jaql scripts work at a high level of abstraction for concise specification of logical operations (eg, join), but Jaql's notion of physical transparency also provides a lower level of abstraction if necessary This allows users to pin down the evaluation plan of a script for greater control or even add new operators The Jaql compiler automatically rewrites Jaql scripts so they can run in parallel on Hadoop In addition to describing Jaql's design, we present the results of scale-up experiments on Hadoop running Jaql scripts for intranet data analysis and log processing

FindU: Privacy-preserving personal profile matching in mobile social networks

Abstract: Making new connections according to personal preferences is a crucial service in mobile social networking, where the initiating user can find matching users within physical proximity of him/her. In existing systems for such services, usually all the users directly publish their complete profiles for others to search. However, in many applications, the users' personal profiles may contain sensitive information that they do not want to make public. In this paper, we propose FindU, the first privacy-preserving personal profile matching schemes for mobile social networks. In FindU, an initiating user can find from a group of users the one whose profile best matches with his/her; to limit the risk of privacy exposure, only necessary and minimal information about the private attributes of the participating users is exchanged. Several increasing levels of user privacy are defined, with decreasing amounts of exchanged profile information. Leveraging secure multi-party computation (SMC) techniques, we propose novel protocols that realize two of the user privacy levels, which can also be personalized by the users. We provide thorough security analysis and performance evaluation on our schemes, and show their advantages in both security and efficiency over state-of-the-art schemes.

The Multiplayer Classroom: Designing Coursework as a Game

Abstract: Discover how to engage your students and raise their grades and attendance in your classroom. THE MULTIPLAYER CLASSROOM: DESIGNING COURSEWORK AS A GAME is your detailed guide to designing any structured learning experience as a game. Written for professional educators or those learning to be educators, here are the tools to engage and excite students by using principles learned in the development of popular video games. Suitable for use in the classroom or the boardroom, the book features a reader-friendly style that introduces game concepts and vocabulary in a logical way. You don't need any experience making games or even playing games to use this book. Yet, you will learn how to create multiplayer games for any age on any subject. Bring your classroom into the 21st century!

Distribution of Ti3+ Surface Sites in Reduced TiO2

Abstract: We describe a DFT + U study of the (110) rutile surface with oxygen vacancies (Ov's). Oxygen vacancies leave behind two excess unpaired electrons per Ov, leading formally to the formation of two Ti3+ ions. We investigate the location of the Ti3+ ions within the first three surface layers. In total, we obtained 49 unique solutions of possible Ti3+ pairs, to examine the stability of all Ti types (e.g., five-coordinated surface Ti, six-coordinated surface Ti, subsurface sites, etc.). Our results show that subsurface sites are preferred but that many configurations are close in energy, within up to 0.3−0.4 eV of each other. In contrast to findings in previous work, we show that sites directly adjacent to the Ov's are unstable. Analysis of our results shows that the two Ti3+ ions within a pair behave independently of each other, as there are little electronic interactions between the excess electrons associated with these sites. We also examined the migration of Ti3+ sites from the surface into the bulk and fi...

CodeOn: Cooperative Popular Content Distribution for Vehicular Networks using Symbol Level Network Coding

Abstract: Driven by both safety concerns and commercial interests, one of the key services offered by vehicular networks is popular content distribution (PCD). The fundamental challenges to achieve high speed content downloading come from the highly dynamic topology of vehicular ad hoc network (VANET) and the lossy nature of the vehicular wireless communications. In this paper, we introduce CodeOn, a novel push-based PCD scheme where contents are actively broadcasted to vehicles from road side access points and further distributed among vehicles using a cooperative VANET. In CodeOn, we employ a recent technique, symbol level network coding (SLNC) to combat the lossy wireless transmissions. Through exploiting symbol level diversity, SLNC is robust to transmission errors and encourages more aggressive concurrent transmissions. In order to fully enjoy the benefits of SLNC, we propose a suite of techniques to maximize the downloading rate, including a prioritized and localized relay selection mechanism where the selection criteria is based on the usefulness of vehicles' possessed contents, and a lightweight medium access protocol that naturally exploits the abundant concurrent transmission opportunities. We also propose additional mechanisms to reduce the protocol overhead without sacrificing the performance. Extensive simulation results show that, under a wide range of scenarios, CodeOn significantly outperforms a state-of-the-art PCD scheme based on network coding.

KT-IDEM: introducing item difficulty to the knowledge tracing model

Abstract: Many models in computer education and assessment take into account difficulty. However, despite the positive results of models that take difficulty in to account, knowledge tracing is still used in its basic form due to its skill level diagnostic abilities that are very useful to teachers. This leads to the research question we address in this work: Can KT be effectively extended to capture item difficulty and improve prediction accuracy? There have been a variety of extensions to KT in recent years. One such extension was Baker's contextual guess and slip model. While this model has shown positive gains over KT in internal validation testing, it has not performed well relative to KT on unseen in-tutor data or post-test data, however, it has proven a valuable model to use alongside other models. The contextual guess and slip model increases the complexity of KT by adding regression steps and feature generation. The added complexity of feature generation across datasets may have hindered the performance of this model. Therefore, one of the aims of our work here is to make the most minimal of modifications to the KT model in order to add item difficulty and keep the modification limited to changing the topology of the model. We analyze datasets from two intelligent tutoring systems with KT and a model we have called KT-IDEM (Item Difficulty Effect Model) and show that substantial performance gains can be achieved with this minor modification that incorporates item difficulty.

Human cryptochrome exhibits light-dependent magnetosensitivity

Abstract: Humans are not believed to have a magnetic sense, even though many animals use the Earth's magnetic field for orientation and navigation. One model of magnetosensing in animals proposes that geomagnetic fields are perceived by light-sensitive chemical reactions involving the flavoprotein cryptochrome (CRY). Here we show using a transgenic approach that human CRY2, which is heavily expressed in the retina, can function as a magnetosensor in the magnetoreception system of Drosophila and that it does so in a light-dependent manner. The results show that human CRY2 has the molecular capability to function as a light-sensitive magnetosensor and reopen an area of sensory biology that is ready for further exploration in humans.

Artemisinin production in Artemisia annua : studies in planta and results of a novel delivery method for treating malaria and other neglected diseases

Abstract: Artemisia annua L. produces the sesquiterpene lactone, artemisinin, a potent antimalarial drug that is also effective in treating other parasitic diseases, some viral infections and various neoplasms. Artemisinin is also an allelopathic herbicide that can inhibit the growth of other plants. Unfortunately, the compound is in short supply and thus, studies on its production in the plant are of interest as are low cost methods for drug delivery. Here we review our recent studies on artemisinin production in A. annua during development of the plant as it moves from the vegetative to reproductive stage (flower budding and full flower formation), in response to sugars, and in concert with the production of the ROS, hydrogen peroxide. We also provide new data from animal experiments that measured the potential of using the dried plant directly as a therapeutic. Together these results provide a synopsis of a more global view of regulation of artemisinin biosynthesis in A. annua than previously available. We further suggest an alternative low cost method of drug delivery to treat malaria and other neglected tropical diseases.

Flash Cookies and Privacy II: Now with HTML5 and ETag Respawning

Abstract: In August 2009, we demonstrated that popular websites were using “Flash cookies” to track users. Some advertisers had adopted this technology because it allowed persistent tracking even where users had taken steps to avoid web profiling. We also demonstrated “respawning” on top sites with Flash technology. This allowed sites to reinstantiate HTTP cookies deleted by a user, making tracking more resistant to users’ privacy-seeking behaviors.In this followup study, we reassess the Flash cookies landscape and examine a new tracking vector, HTML5 local storage and Cache-Cookies via ETags. We found over 5,600 standard HTTP cookies on popular sites, over 4,900 were from third parties. Google-controlled cookies were present on 97 of the top 100 sites, including popular government websites. Seventeen sites were using HTML5, and seven of those sites had HTML5 local storage and HTTP cookies with matching values. Flash cookies were present on 37 of the top 100 sites. We found two sites that were respawning cookies, including one site – hulu.com – where both Flash and cache cookies were employed to make identifiers more persistent. The cache cookie method used ETags, and is capable of unique tracking even where all cookies are blocked by the user and “Private Browsing Mode” is enabled.Our 2009 study is also available at SSRN: http://ssrn.com/abstract=1446862.

Highly Active Iridium/Iridium–Tin/Tin Oxide Heterogeneous Nanoparticles as Alternative Electrocatalysts for the Ethanol Oxidation Reaction

Abstract: Ethanol is a promising fuel for low-temperature direct fuel cell reactions due to its low toxicity, ease of storage and transportation, high-energy density, and availability from biomass. However, the implementation of ethanol fuel cell technology has been hindered by the lack of low-cost, highly active anode catalysts. In this paper, we have studied Iridium (Ir)-based binary catalysts as low-cost alternative electrocatalysts replacing platinum (Pt)-based catalysts for the direct ethanol fuel cell (DEFC) reaction. We report the synthesis of carbon supported Ir(71)Sn(29) catalysts with an average diameter of 2.7 ± 0.6 nm through a "surfactant-free" wet chemistry approach. The complementary characterization techniques, including aberration-corrected scanning transmission electron microscopy equipped with electron energy loss spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and X-ray absorption spectroscopy, are used to identify the "real" heterogeneous structure of Ir(71)Sn(29)/C particles as Ir/Ir-Sn/SnO(2), which consists of an Ir-rich core and an Ir-Sn alloy shell with SnO(2) present on the surface. The Ir(71)Sn(29)/C heterogeneous catalyst exhibited high electrochemical activity toward the ethanol oxidation reaction compared to the commercial Pt/C (ETEK), PtRu/C (Johnson Matthey) as well as PtSn/C catalysts. Electrochemical measurements and density functional theory calculations demonstrate that the superior electro-activity is directly related to the high degree of Ir-Sn alloy formation as well as the existence of nonalloyed SnO(2) on surface. Our cross-disciplinary work, from novel "surfactant-free" synthesis of Ir-Sn catalysts, theoretical simulations, and catalytic measurements to the characterizations of "real" heterogeneous nanostructures, will not only highlight the intriguing structure-property correlations in nanosized catalysts but also have a transformative impact on the commercialization of DEFC technology by replacing Pt with low-cost, highly active Ir-based catalysts.

Integrating reinforcement learning with human demonstrations of varying ability

Abstract: This work introduces Human-Agent Transfer (HAT), an algorithm that combines transfer learning, learning from demonstration and reinforcement learning to achieve rapid learning and high performance in complex domains. Using experiments in a simulated robot soccer domain, we show that human demonstrations transferred into a baseline policy for an agent and refined using reinforcement learning significantly improve both learning time and policy performance. Our evaluation compares three algorithmic approaches to incorporating demonstration rule summaries into transfer learning, and studies the impact of demonstration quality and quantity, as well as the effect of combining demonstrations from multiple teachers. Our results show that all three transfer methods lead to statistically significant improvement in performance over learning without demonstration. The best performance was achieved by combining the best demonstrations from two teachers.

Review: A review and analysis of current computer-aided fixture design approaches

Abstract: A key characteristic of the modern market place is the consumer demand for variety. To respond effectively to this demand, manufacturers need to ensure that their manufacturing practices are sufficiently flexible to allow them to achieve rapid product development. Fixturing, which involves using fixtures to secure workpieces during machining so that they can be transformed into parts that meet required design specifications, is a significant contributing factor towards achieving manufacturing flexibility. To enable flexible fixturing, considerable levels of research effort have been devoted to supporting the process of fixture design through the development of computer-aided fixture design (CAFD) tools and approaches. This paper contains a review of these research efforts. Over seventy-five CAFD tools and approaches are reviewed in terms of the fixture design phases they support and the underlying technology upon which they are based. The primary conclusion of the review is that while significant advances have been made in supporting fixture design, there are primarily two research issues that require further effort. The first of these is that current CAFD research is segmented in nature and there remains a need to provide more cohesive fixture design support. Secondly, a greater focus is required on supporting the detailed design of a fixture's physical structure.

Dependable and Secure Sensor Data Storage with Dynamic Integrity Assurance

Abstract: Recently, distributed data storage has gained increasing popularity for efficient and robust data management in wireless sensor networks (WSNs). The distributed architecture makes it challenging to build a highly secure and dependable yet lightweight data storage system. On the one hand, sensor data are subject to not only Byzantine failures, but also dynamic pollution attacks, as along the time the adversary may modify/pollute the stored data by compromising individual sensors. On the other hand, the resource-constrained nature of WSNs precludes the applicability of heavyweight security designs. To address the challenge, in this article we propose a novel dependable and secure data storage scheme with dynamic integrity assurance. Based on the principle of secret sharing and erasure coding, we first propose a hybrid share generation and distribution scheme to achieve reliable and fault-tolerant initial data storage by providing redundancy for original data components. To further dynamically ensure the integrity of the distributed data shares, we then propose an efficient data integrity verification scheme exploiting the techniques of algebraic signature and spot-checking. The proposed scheme enables individual sensors to verify in one protocol execution the correctness of all the pertaining data shares simultaneously in the absence of the original data. Extensive security analysis shows that the proposed scheme has strong resistance against various data pollution attacks. The efficiency of the scheme is demonstrated by experiments on sensor platforms Tmote Sky and iMote2.

Combining Dynamic Stretch and Tunable Stiffness to Probe Cell Mechanobiology In Vitro

Abstract: Cells have the ability to actively sense their mechanical environment and respond to both substrate stiffness and stretch by altering their adhesion, proliferation, locomotion, morphology, and synthetic profile. In order to elucidate the interrelated effects of different mechanical stimuli on cell phenotype in vitro, we have developed a method for culturing mammalian cells in a two-dimensional environment at a wide range of combined levels of substrate stiffness and dynamic stretch. Polyacrylamide gels were covalently bonded to flexible silicone culture plates and coated with monomeric collagen for cell adhesion. Substrate stiffness was adjusted from relatively soft (G9=0.3 kPa) to stiff (G9=50 kPa) by altering the ratio of acrylamide to bis-acrylamide, and the silicone membranes were stretched over circular loading posts by applying vacuum pressure to impart near-uniform stretch, as confirmed by strain field analysis. As a demonstration of the system, porcine aortic valve interstitial cells (VIC) and human mesenchymal stem cells (hMSC) were plated on soft and stiff substrates either statically cultured or exposed to 10% equibiaxial or pure uniaxial stretch at 1Hz for 6 hours. In all cases, cell attachment and cell viability were high. On soft substrates, VICs cultured statically exhibit a small rounded morphology, significantly smaller than on stiff substrates (p,0.05). Following equibiaxial cyclic stretch, VICs spread to the extent of cells cultured on stiff substrates, but did not reorient in response to uniaxial stretch to the extent of cells stretched on stiff substrates. hMSCs exhibited a less pronounced response than VICs, likely due to a lower stiffness threshold for spreading on static gels. These preliminary data demonstrate that inhibition of spreading due to a lack of matrix stiffness surrounding a cell may be overcome by externally applied stretch suggesting similar mechanotransduction mechanisms for sensing stiffness and stretch.

Online Viewing and Aesthetic Preferences of Generation Y and the Baby Boom Generation: Testing User Web Site Experience Through Eye Tracking

Abstract: The baby boom generation, born from 1946 to 1964, and Generation Y, born from 1977 to 1990, form two important groups of online users in terms of numbers and economic impact. Understanding their Web preferences is of great importance to companies, particularly because the literature suggests that these generations may differ in how they view Web pages and in what they find visually pleasing. To this end, a laboratory experiment examined users' reactions to a set of home pages. Users' reactions were captured using self-report measures and eye tracking, which recorded fixations. Overall, both generations reported similar aesthetic preferences, and both generations preferred pages that had images and little text. However, the two generations also displayed different online viewing behavior and preferences. For instance, eye-tracking data revealed that baby boomers had significantly more fixations and that their fixations covered more of the pages (e.g., headers, main body, sidebars) than those of Generation Yers. In addition, baby boomers reported a significantly higher tolerance for having more Web components on a page. These results suggest that Generation Yers will be more likely than baby boomers to miss key information if a Web page fails to present that information using a limited number of clear focal points that are located above the fold of the page. The relationship observed between viewing behavior and visual appeal supports the importance of aesthetics in usability research. Moreover, this research suggests that companies targeting either generation could benefit from being mindful of the visual appeal of their Web site.

Restoration of Skeletal Muscle Defects with Adult Human Cells Delivered on Fibrin Microthreads

Abstract: Large-scale musculoskeletal wounds, such as those seen in trauma injuries, present poor functional healing prognoses. In severe trauma, when the native tissue architecture is destroyed or lost, the...