Static Content Research Articles

Deformation Characteristics of Textile and Grid Reinforced Asphalt Concrete Pavement Model

In this paper, a laboratory investigation has been conducted to evaluate the deformation characteristics of reinforced Asphalt concrete pavement. Two types of reinforcements have been implemented; the first type is biaxial plastic geogrids of two different aperture sizes and rib thickness, while the second type was the nonwoven continuous fiber geotextile with two different thicknesses. The Asphalt concrete mix was designed as per Marshall Procedure using super pave requirements for gradation. To investigate the deformation characteristics, Circular slab specimens of different thickness have been constructed using static compaction and optimum asphalt content. Slab specimens were coupled and the reinforcements were introduced in between, then, tested in a model box of 50 x50 x70 cm filled with loose sand layer of 40 cm thickness representing the existing poorsubgrade condition. A total of 60 circular slab specimens have been constructed and tested in duplicate. The load - deformation data were recorded, plotted, and analyzed for the deformation characteristics. The effect of pavement thickness, Asphalt concrete stiffness, reinforcement type were also analyzed and discussed.

Social Tools for Networked Learning

Whereas the Web 1.0 was mainly driven by static content and web pages linked by hyperlinks, the social web, or Web 2.0, has opened up new ways of connecting to not just resources, but also to people. The connections that are made through the use of Social Media, contribute to a complex, but also promising network of people and resources. In an educational context, this is called a learning network, and both learning networks by themselves and the Social media by which they are constructed require that we rethink the ways we learn, our view on learners, tutors and learning, and the way we support learners and tutors. Numerous opportunities have emerged with the introduction of social media for learning, but so have numerous problems, ranging from awareness issues via (meta-)cognitive limitations and difficulties to affective and motivational problems. This paper addresses the above issues by providing an overview of the current research we perform. The research we do is based on three themes: Peer support, Learner support and Online Learner Identity. Peer support describes the way peers may help each other through effective and efficient use of a learning network. It uses 1) natural language processing to, for instance, analyse communication between learners, 2) mine learner profiles to adapt to their individual circumstances and identity and 3) social network analysis extended by game theoretic solution concepts to recommend suitable peers for cooperative learning. Learner support focuses on how we may lead the learner through the jungle of learning resources. It uses recommender techniques to filter out unnecessary learning resources and provides concise sets of candidate resources for learning. Finally, Online Learner Identity focuses on rethinking how we construct our online identity, how to analyse such, and how to profit from the differences with offline learning. It may use multi-agent systems technology to simulate the identity of learners and their interaction in a learning network, but also semantic technology to capture the meaning of online learner identities. The paper also describes the main techniques that we use in our research efforts to enhance networked learning. Furthermore, an overview of current projects within the themes is provided. We conclude that the results of our current research efforts will provide valuable insights to advance further on research and development of social tools for networked learning.

Supporting Accessibility for Blind and Vision‐impaired People With a Localized Gazetteer and Open Source Geotechnology

AbstractDisabled people, especially the blind and vision‐impaired, are challenged by many transitory hazards in urban environments such as construction barricades, temporary fencing across walkways, and obstacles along curbs. These hazards present a problem for navigation, because they typically appear in an unplanned manner and are seldom included in databases used for accessibility mapping. Tactile maps are a traditional tool used by blind and vision‐impaired people for navigation through urban environments, but such maps are not automatically updated with transitory hazards. As an alternative approach to static content on tactile maps, we use volunteered geographic information (VGI) and an Open Source system to provide updates of local infrastructure. These VGI updates, contributed via voice, text message, and e‐mail, use geographic descriptions containing place names to describe changes to the local environment. After they have been contributed and stored in a database, we georeference VGI updates with a detailed gazetteer of local place names including buildings, administrative offices, landmarks, roadways, and dormitories. We publish maps and alerts showing transitory hazards, including location‐based alerts delivered to mobile devices. Our system is built with several technologies including PHP, JavaScript, AJAX, Google Maps API, PostgreSQL, an Open Source database, and PostGIS, the PostgreSQL's spatial extension. This article provides insight into the integration of user‐contributed geospatial information into a comprehensive system for use by the blind and vision‐impaired, focusing on currently developed methods for geoparsing and georeferencing using a gazetteer.

Noncespaces: Using randomization to defeat cross-site scripting attacks

Cross-site scripting (XSS) vulnerabilities are among the most common and serious web application vulnerabilities. It is challenging to eliminate XSS vulnerabilities because it is difficult for web applications to sanitize all user input appropriately. We present Noncespaces, a technique that enables web clients to distinguish between trusted and untrusted content to prevent exploitation of XSS vulnerabilities. Using Noncespaces, a web application randomizes the the (X)HTML tags and attributes in each document before delivering it to the client. As long as the attacker is unable to guess the random mapping, the client can distinguish between trusted content created by the web application and untrusted content provided by an attacker. To implement Noncespaces with minimal changes to web applications, we leverage a popular web application architecture to automatically apply Noncespaces to static content processed through a popular PHP template engine. We design a policy language for Noncespaces, implement a training mode to assist policy development, and conduct extensive security testing of a generated policy for two large web applications to show the effectiveness of our technique.

Monitoring high performance data streams in vertical markets: Theory and applications in public safety and healthcare

Over the last several years, monitoring high performance data stream sources has become very important in various vertical markets. For example, in the public safety sector, monitoring and automatically identifying individuals suspected of terrorist or criminal activity without physically interacting with them has become a crucial security function. In the healthcare industry, noninvasive mechanical home ventilation monitoring has allowed patients with chronic respiratory failure to be moved from the hospital to a home setting without jeopardizing quality of life. In order to improve the efficiency of large data stream processing in such applications, we contend that data stream management systems (DSMS) should be introduced into the monitoring infrastructure. We also argue that monitoring tasks should be performed by executing data stream queries defined in Continuous Query Language (CQL), which we have extended with: 1) new operators that allow creation of a sophisticated event-based alerting system through the definition of threshold schemes and threshold activity scheduling, and 2) multimedia support, which allows manipulation of continuous multimedia data streams using a similarity-based join operator which permits correlation of data arriving in multimedia streams with static content stored in a conventional multimedia database. We developed a prototype in order to assess these proposed concepts and verified the effectiveness of our framework in a lab environment.

Tutorial videos of bioinformatics resources: online distribution trial in Japan named TogoTV

In recent years, biological web resources such as databases and tools have become more complex because of the enormous amounts of data generated in the field of life sciences. Traditional methods of distributing tutorials include publishing textbooks and posting web documents, but these static contents cannot adequately describe recent dynamic web services. Due to improvements in computer technology, it is now possible to create dynamic content such as video with minimal effort and low cost on most modern computers. The ease of creating and distributing video tutorials instead of static content improves accessibility for researchers, annotators and curators. This article focuses on online video repositories for educational and tutorial videos provided by resource developers and users. It also describes a project in Japan named TogoTV (http://togotv.dbcls.jp/en/) and discusses the production and distribution of high-quality tutorial videos, which would be useful to viewer, with examples. This article intends to stimulate and encourage researchers who develop and use databases and tools to distribute how-to videos as a tool to enhance product usability.

A quantitative study of Web cache replacement strategies using simulation

The Web has become the most important source of information and communication for the world. Proxy servers are used to cache objects with the goals of decreasing network traffic, reducing user perceived lag and loads on origin servers. In this paper, we focus on the cache replacement problem with respect to proxy servers. Despite the fact that some Web 2.0 applications have dynamic objects, most of the Web traffic has static content with file types such as cascading style sheets, javascript files, images, etc. The cache replacement strategies implemented in Squid, a widely used proxy cache software, are no longer considered ‘good enough’ today. Squid’s default strategy is Least Recently Used. While this is a simple approach, it does not necessarily achieve the targeted goals. We simulate 27 proxy cache replacement strategies and analyze them against several important performance measures. Hit rate and byte hit rate are the most commonly used performance metrics in the literature. Hit rate is an indication of user perceived lag, while byte hit rate is an indication of the amount of network traffic. We also introduce a new performance metric, the object removal rate, which is an indication of CPU usage and disk access at the proxy server. This metric is particularly important for busy cache servers or servers with lower processing power. Our study provides valuable insights for both industry and academia. They are especially important for Web proxy cache system administrators; particularly in wireless ad-hoc networks as the caches on mobile devices are relatively small.

Performance-Enhanced Caching Scheme for Web Clusters for Dynamic Content

In order to improve the QoS of applications, clusters of web servers are increasingly used in web services. Caching helps improve performance in web servers, but is largely exploited only for static web content. With more web applications using backend databases today, caching of dynamic content has a crucial role in web performance. This paper presents a set of cache management schemes for handling dynamic data in web clusters by sharing cached contents. These schemes use either automatic or expiry-based cache validation, and work with any type of request distribution. The techniques improve response by utilizing the caches efficiently and reducing redundant database accesses by web servers while ensuring cache consistency. The authors present caching schemes for both horizontal and vertical cluster architectures. Simulations show an appreciable performance rise in response times of queries in clustered web servers.

Fostering Learner Mobility Between Engineering Education and a Twenty First Century Workplace

Engineering education today is undergoing unprecedented array of challenges, especially in the teaching and learning process. Among other challenges in this area students now require multiple stimuli, they have very low tolerance for monotonous static content, and they are highly mobile. To address some of these challenges, the authors have conducted a pilot study with Learner Agent Objects (LAO) individual portfolios. LAO portfolios are collections of artifacts (studentsâ?? best work) representing a learner's academic experience. LAO affords a foundation for creating a more comprehensive and seamless movement of learners between jurisdictions in engineering education and the workplace. A more seamless movement of individuals between formal education, informal education and the workplace has significant implications for the learning environments and ecosystems of engineers as lifelong learners.

내러티브 구조 관점에서 본 게임 캐릭터의 퀘스트 플레이에 대한 인터랙션 사전 시각화

게임기획자는 내러티브를 기반으로 퀘스트의 초기 설계를 한다. 이러한 게임의 정적 컨텐트 수립에 있어 게임캐릭터의 플레이경험을 사전 예측하는 것은 중요하다. 본 논문은 게임캐릭터가 고유한 스테이터스를 바탕으로 퀘스트 플레이를 수행함에 있어 캐릭터간 구별되는 정서적 인터랙션을 시각화 할 수 있는 방법에 대해 다루고 있다. 이를 위해 첫째, 기존 영상매체에서 내러티브 구조의 시각화에 대한 연구를 바탕으로 둘째, 퀘스트플레이 경험과 플레이어 인지행동을 구체화하였다. 셋째, 사례분석을 통해 캐릭터별 퀘스트플레이 과정에서의 차이를 QUG(Quest Unit Graph)로 시각화하여 직관적인 확인이 가능하도록 하였다. 기존 연구가 캐릭터별 성취(achievement)관점에서의 수치적 밸런스 대한 것에 반해, 본 논문은 내러티브 구조 관점에서 퀘스트플레이 인터랙션에 대한 시각화 모델을 제안함으로써 기획자의 퀘스트 경험설계를 사전 예측해 볼 수 있다.

The Collage Authoring Environment

Abstract The Collage Authoring Environment is a software infrastructure which enables domain scientists to collaboratively develop and publish their work in the form of executable papers. It corresponds to the recent developments in both e-Science and computational technologies which call for a novel publishing paradigm. As part of this paradigm, static content (such as traditional scientific publications) should be supplemented with elements of interactivity, enabling reviewers and readers to reexamine the reported results by executing parts of the software on which such results are based as well as access primary scientific data. Taking into account the presented rationale we propose an environment which enables authors to seamlessly embed chunks of executable code (called assets) into scientific publications and allow repeated execution of such assets on underlying computing and data storage resources, as required by scientists who wish to build upon the presented results. The Collage Authoring Environment can be deployed on arbitrary resources, including those belonging to high performance computing centers, scientific e-Infrastructures and resources contributed by the scientists themselves. The environment provides access to static content, primary datasets (where exposed by authors) and executable assets. Execution features are provided by a dedicated engine (called the Collage Server) and embedded into an interactive view delivered to readers, resembling a traditional research publication but interactive and collaborative in its scope. Along with a textual description of the Collage environment the authors also present a prototype implementation, which supports the features described in this paper. The functionality of this prototype is discussed along with theoretical assumptions underpinning the proposed system.

Skype Video congestion control: An experimental investigation

The Internet is facing a significant evolution from being a delivery network for static content to an efficient platform for multimedia content delivery. Well-known examples of applications driving this evolution are YouTube Video on Demand, Skype Audio/Video conference, IPTV and P2P video distribution. While YouTube streams videos using the Transmission Control Protocol (TCP), time-sensitive applications, such as Skype Audio/Video conference, employ the UDP because they can tolerate small loss percentages but not delays due to TCP recovery of lost packets via retransmissions. Since, differently from the TCP, the UDP does not implement congestion control, these applications must implement congestion control at the application layer in order to avoid congestion and preserve network stability. In this paper we investigate Skype Video congestion control in order to assess to what extent this application is able to throttle its sending rate to match the unpredictable Internet bandwidth while preserving resource for co-existing best-effort TCP traffic. We have found that: (1) Skype Video adapts its sending rate by varying frame rate, frame quality and video resolution; (2) in many scenarios a Skype Video call refrains from fully utilizing all available bandwidth thus not sending videos at the highest possible quality; (3) Skype Video employs an adaptive FEC action that is proportional to the experienced loss rate; (4) the sending rate matches a changing available bandwidth with a transient time as large as a hundred of seconds; (5) the minimum bandwidth required for a video call is 40kbps at 5 frames per second.

Quantitative Measurement of Ca 2+ in the Sarcoplasmic Reticulum Lumen of Mammalian Skeletal Muscle

Skeletal muscle stores Ca 2+ in the sarcoplasmic reticulum (SR) and releases it to initiate contraction, but the concentration of luminal Ca 2+ in the SR ([Ca 2+] SR) and the amount that is released by physiological or pharmacological stimulation has been difficult to measure. Here we present a novel, yet simple and direct, method that provides the first quantitative estimates of static content and dynamic changes in [Ca 2+] SR in mammalian skeletal muscle, to our knowledge. The method uses fluo-5N loaded into the SR of single, mammalian skeletal muscle cells (murine flexor digitorum brevis myofibers) and confocal imaging to detect and calibrate the signals. Using this method, we have determined that [Ca 2+] SR, free is 390 μM. 4-Chloro-m-cresol, an activator of the skeletal muscle ryanodine receptor, reduces [Ca 2+] SR, free to ∼8 μM, when values are corrected for background fluorescence from cytoplasmic pools of dye. Prolonged electrical stimulation (10 s) at 50 Hz releases 88% of the SR Ca 2+ content, whereas stimulation at 1 Hz (10 s) releases only 20%. Our results lay the foundation for molecular modeling of the dynamics of luminal SR Ca 2+ and for future studies of the role of SR Ca 2+ in healthy and diseased mammalian muscle.

Merging Strategies for Authoring QoE-based Adaptive Hypermedia

Personalization is desirable, but writing the adaptation behaviour description to go with it is taxing. Even more challenging is the application of multiple adaptation strategies over the same static content. This paper focuses on recent work on strategy modularisation and merger development in the authoring process ofadaptive hypermedia. The reason for the modularisation of strategies is to break a complex adaptation decision into a number of simpler ones, which may be reused more easily and applied in different orders. The rationale for strategy merger is to be able to apply multiple adaptation strategies over the same content - a challenge which is not yet fully addressed in current adaptive hypermedia systems. To demonstrate the proposed method we present an example case study and sample strategies written in the LAG adaptation language. The case study is based on a recently proposed model for Quality of Experience in e-learning. This model exposes the complex interaction between a number of factors affecting QoE and hence presents a good candidate for the application of a strategy merger, as well as modularisation. We have then evaluated this approach via structured questionnaires used with a number of design experts of hypermedia content creation, especially in the domain of education. This allows us to draw generic conclusions for both our own further research, as well as for the community at large, interested in the area of reuse and modularisation of adaptation.

GIS Enabled PBL Pedagogy: the Effects on Students� Learning in the Classroom

In efforts aimed at acquainting learners with ‘how to learn’ skills rather than static content knowledge, more student-centric instructional approaches are being increasingly adopted in informing curriculum design and delivery. Technology-rich problem solving environments offer great promise in scaffolding and facilitating student-centred learning. Geographic information system is one powerful technology that enables learners to become proficient spatial problem solvers, analytical users of geographic information and expert decision makers. This paper investigates the pedagogical benefits of GIS in influencing students’ problem solving performances in Singapore. Data was collected by administering a likert-scale based questionnaire constructed specifically for this study and analysed using statistical method. Students participated in this research highlighted many of the instructional strengths of GIS that enabled them to become competent problem solvers and self-directed learners. They also pointed out some of the challenges which educators need to bear in mind in the development and enactment of GIS enabled pedagogy.

Implementation of an Assessment System Incorporating Web-based Parameterized Questions

This paper presents a web-based assessment system, which supports parameterized questions, incorporating remote web services/applications, in order to use them during the evaluation process. The proposed system introduces a dynamic technique for creating a new type of parameterized web-based questions which mix static and dynamic content and thus, it operates as an integration framework, incorporating these remote web services/applications as part of the evaluation process. The technique is based on question templates, which contain the details of the remote services/applications that provide the correct answer in each question. The incorporation of remote web-based services into a parameterized assessment system, as part of the evaluation process, constitutes an advanced feature that provides new capabilities, such as flexibility and extensibility to any assessment system.

Learning objects in theory and practice: A vision from Mexican University teachers

Drawing on the experience of development and use of a virtual learning environment (VLE) at a public Mexican university, this article explores the tension between the most common definitions and attributes of learning object (LO) in the mainstream literature, and the teacher’s practices around the creation and incorporation of LOs in the VLE. This experience shows that attempting to define LOs from strictly technical or industrial parameters might be limiting in the context of educational institutions, since teachers are developing and using LOs effectively, despite their little adherence to prescriptive definitions. Yet it is important to support teachers in order to take advantage of the interactive and multimedia potentialities afforded by this technology, instead of using it mostly for delivering static content.

An approximation-based load-balancing algorithm with admission control for cluster web servers with dynamic workloads

The growth of web-based applications in business and e-commerce is building up demands for high performance web servers for better throughputs and lower user-perceived latency. These demands are leading to a widespread substitution of powerful single servers by robust newcomers, cluster web servers, in many enterprise companies. In this respect the load-balancing algorithms play an important role in boosting the performance of cluster servers. The previous load-balancing algorithms which were designed for the handling of static contents in web services suffer from significant performance degradation under dynamic and database-driven workloads. Regarding this, we propose an approximation-based load-balancing algorithm with admission control for cluster-based web servers in this study. Since it is difficult to accurately determine the loads of web servers through feedbacks from distributed agents in web servers, we propose an analytical model of a web server to estimate the web servers' loads. To achieve this, the algorithm classifies requests based on their service times and track numbers of outstanding requests for each class of each web server node and also based on their resource demands to dynamically estimate the loads of each node. For the error handling of the model a proportional integral (PI) controller from control theory is used. Then the estimated available capacity of each web server is used for load balancing and admission control decisions. The implementation results with a standard benchmark confirm the effectiveness of the proposed scheme, which improves both the mean response time and the throughput of the cluster compared to rival load-balancing algorithms, and also avoids situations in which the cluster is overloaded, even when the request rates are beyond the cluster capacity.

Combining internet collected data to build personalised location based services

In this article, a framework that allows mobile users to build, deploy and distribute personalised mobile services is described. The core of the framework lies in the integration of static and dynamic content from various web sources, from system data and from the personal user preferences, and is combined to form mashups. These mashups will be customised appropriately so as to support the provision of mobile services in a time dependent, location aware, context driven and, finally, personalised manner. The framework has been implemented based on pocket PC user devices, and can be deployed over any internet protocol supporting network architecture. The evaluation of the proposed framework is being carried out with the aid of an open source context simulator.

High-Performance Resource Allocation and Request Redirection Algorithms for Web Clusters

With increasing richness in features such as personalization of content, Web applications are becoming increasingly complex and hence compute intensive. Traditional approaches for improving performance of static content Web sites have been based on the assumption that static content such as images are network intensive. However, these methods are not applicable to the dynamic content applications which are more compute intensive than static content. This paper proposes a suite of algorithms which jointly optimize the performance of dynamic content applications by reducing the client access times while also minimizing the resource utilization. A server migration algorithm allocates servers on-demand within a cluster such that the client access times are not affected even under sudden overload conditions. Further, a server selection mechanism enables statistical multiplexing of resources across clusters by redirecting requests away from overloaded clusters. We also propose a cluster decision algorithm which decides whether to migrate in additional servers at the local cluster or redirect requests remotely under different workload conditions. Through a combination of analytical modeling, trace-driven simulation over traces from large e-commerce sites and testbed implementation, we explore the performance savings achieved by the proposed algorithms.