Concurrent Users Research Articles

An integrated prefetching/caching scheme in multimedia servers

Advances in storage and networking technologies have made on-demand multimedia services prevalent these days. To provide numerous concurrent users with such high-quality services, it is essential for storage systems to support sufficient I/O bandwidth for delivering multimedia data on time. Two data buffering techniques, prefetching and interval caching, have improved I/O performance by keeping data blocks in memory for future accesses when handling multimedia data with sequential access patterns. However, they have been addressed separately since it is challenging to determine whether it is better to prefetch or to cache each new stream depending on specific situations. Prefetching too many blocks or caching too long intervals may exhaust the cache space quickly. In this paper, we propose a scheme, called Integrated Prefetching/Caching (IPC), to simultaneously take benefit of both prefetching and interval caching using dynamic threshold values. The IPC schedules incoming streaming requests so that utilization of both cache space and disk bandwidth can be maximized. As a result, the IPC can continue to improve the performance without saturation as system resources are added. By simulation experiments, we show that IPC increases the number of concurrent streams significantly, compared to when either prefetching or caching is employed alone.

Scalability and Performance of Selected Websites of Universities: An Analytical Study of Punjab (India)

Today, education has emerged as a major area of commercial activities. The access to various University websites through Internet has opened up new opportunities for the beneficiaries. The creation of these websites fully serves the purpose of educational institutions in advancing and achieving their goals. The varied information made available on these websites and the minimum transaction response time to address the queries of end-users can go a long way to influence their decision in selecting a particular course and an institution. The issue assumes greater significance especially in a developing country like India where a website development and deployment activity is primarily facing the shortage of formalized website design techniques and testing procedures. The performance of most of the University websites is reasonably well, but when accessed by only a few concurrent users. Thus, the aim of this study is to analyze and compare the scalability and performance of selected University websites of Punjab (India) by means of load testing. Simulation of realistic users’ behavior is achieved through LoadRunner, a software tool for performance testing. Of all the University websites under study, on the basis of their scalability and performance, it has been found that the websites of Deemed and Central universities are the most and least efficient respectively. The findings of this study can be of great significance for the higher educational institutions in improving the performance quality of their websites resulting into their better ranking and satisfaction of the stakeholders. The paper also outlines the scope for further research in the area under study.

Berliner Philharmoniker Digital Concert Hall

Reviewed by: Berliner Philharmoniker Digital Concert Hall Lisa Hooper Berliner Philharmoniker Digital Concert Hall [Berlin, Germany]: Berliner Philharmoniker, (2016–). http://www.digitalconcerthall.com/ (accessed 30 December 2016). [Requires a Web browser and Internet connection or personal device and Internet/data connection. Pricing: varies by institutional or individual subscription.] Introduction The Berliner Philharmoniker Digital Concert Hall is a Web-based database of streaming video performances, documentaries, and interviews by and related to the Berlin Philharmonic. This resource first became available in beta form in October 2015. Beta testing ended in January 2016, and the resource became available by subscription that spring. The resource Web site does not clearly define its scope but it is self-evident that this is a product of the Berlin Philharmonic. On the How It Works page, it is noted that “each season around 40 concerts are broadcasted live and they can also be viewed at a later date in the concert archive. The archive already contains hundreds of recordings with all the great artists of classical music. There are also fascinating documentaries and bonus films.” (https://www.digitalconcerthall.com/en/ info, accessed 30 December 2016). Pricing & Access Digital Concert Hall does not publicly share its pricing index, instead requiring institutions to complete a questionnaire to receive a “personalized quote.” Information taken into account includes institution type (university, conservatory, school, other), total FTE enrollment, the number of students majoring or minoring in music, the number of students attending music classes, and the number of students using music resources. Similar information about institutional personnel is required, including the number of faculty, number of librarians, and number of support staff as well as how these groups use musical resources. More common information such as number of concurrent users and subscription duration (one, two, or three years) is also considered. Content Streaming video content begins in 1966 and continues to the present with live concert streams that are subsequently added to the archive. Content is batched into date ranges. The earliest content, 1966 to 1979, contains seventeen concerts and two documentaries all with Herbert von Karajan. The period 1980 to 1989 only contains three items, but all three may be considered significant performances in the orchestra’s history. Seventeen concerts, conducted variously by Claudio Abbado, Daniel Barenboim, James Levine, Bernard Haitink, Sir Simon Rattle, and Sergiu Celibidache, are in the 1990 to 1999 batch. The time period of 2000 to 2008, contains thirty-three concerts conducted by Simon Rattle, Mark Elder, Neeme Järvi, Daniel Barenboim, Seiji Ozawa, Pierre Boulez, Mariss Jansons, Claudio Abbado, Plácido Domingo, Lorin Maazel, and Kent Nagano. From 2008 on performances are organized by season, with thirty-five performances in the 2008/9 season and later seasons containing forty-two to fifty items each. The current 2016/17 season contains twenty-three concerts with the promise to grow. Some content is also available on CD or DVD. A comparison of Digital Concert Hall and the Berliner Philharmoniker Recordings Shop (https://www.berliner-philharmoniker-recordings.com, accessed 27 January 2017), linked in the page header, reveals a limited degree of overlap. [End Page 761] For example, both include video of Rattle’s Sibelius symphony cycle (BPHR 150071, OCLC accession number 925527825). Conversely, the interview with Harnoncourt available in the Recordings Shop as a bonus DVD to the conductor’s complete Schubert recordings (BPHR 150061, OCLC accession number 959284299) is sadly omitted from the Digital Concert Hall. Historical recordings may be available via Alexander Street Press’s Music Online as streaming audio only. However, content originally released on the Berliner Philharmoniker label is not duplicated by other streaming resources. All of the conducting giants, and many more, that worked with the orchestra since the mid-60s are represented. The database reveals a preference for traditional musical fare: Beethoven (61 performances), Brahms (54), Mahler (39), and Mozart (38). Although far fewer, works from the late twentieth and twenty-first centuries are represented as well, with compositions by Luciano Berio (12), Elliot Carter (3), George Crumb (1), Luigi Dallapiccola (1), Jonathan Dove (1), Osvaldo Golijov (1), Paul Hindemith (6), Kaija Saariaho (1), and TMru Takemitsu (1), among others. The resource undoubtedly has commercial drivers behind it. A direct link...

MobisenseCar: A Mobile Crowd-Based Architecture for Data Acquisition and Processing in Vehicle-Based Sensing

The use of wireless technology via smartphone allows designing smartphone applications based on OBD-II for increasing environment sensing. However, uploading of vehicle’s diagnostics data via car driver’s tethered smart phone attests a long Internet latency when a large number of concurrent users use the remote mobile crowdsensing server application simultaneously, which increases the communication cost. The large volume of data would also challenge the traditional data processing framework. This paper studies design functionalities of mobile crowdsensing architecture applied to vehicle-based sensing for handling a huge amount of sensor data collected by those vehicle-based sensors equipped with a smart device connected to the OBD-II interface. The proposed MobiSenseCar uses Node.js, a web server architecture based on single-thread event loop approach and Apache Hive platform responsible for analyzing vehicle’s engine data. The Node.JS is 40% faster than the traditional web server side features thread-based approach. Experiment results show that MapReduce algorithm is highly scalable and optimized for distributed computing. With this mobile crowdsensing architecture it was possible to monitor information of car’s diagnostic system condition in real time, improving driving ability and protect the environment by reducing vehicle emissions.

Performance Evaluation of Public IaaS Clouds for Web 2.0 Applications Using CloudStone Benchmark

Web 2.0 applications have become ubiquitous over the past few years because they provide useful features such as a rich, responsive graphical user interface that supports interactive and dynamic content. Social networking websites, blogs, auctions, online banking, online shopping and video sharing websites are noteworthy examples of Web 2.0 applications. The market for public cloud service providers is growing rapidly, and cloud providers offer an ever-growing list of services. As a result, developers and researchers find it challenging when deciding which public cloud service to use for deploying, experimenting or testing Web 2.0 applications. This study compares the scalability and performance of a social-events calendar application on two Infrastructure as a Service (IaaS) cloud services – Amazon EC2 and HP Cloud. This study captures and compares metrics on three different instance configurations for each cloud service such as the number of concurrent users (load), as well as response time and throughput (performance). Additionally, the total price of the three different instance configurations for each cloud service is calculated and compared. This comparison of the scalability, performance and price metrics provides developers and researchers with an insight into the scalability and performance characteristics of the three instance configurations for each cloud service, which simplifies the process of determining which cloud service and instance configuration to use for deploying their Web 2.0 applications. This study uses CloudStone – an open-source, three-tier web application benchmarking tool that simulates Web 2.0 application activities – as a realistic workload generator and to capture the intended metrics. The comparison of the collected metrics indicates that all of the tested Amazon EC2 instance configurations provide better scalability and lower latency at a lower cost than the respective HP Cloud instance configurations; however, the tested HP Cloud instance configurations provide a greater storage capacity than the Amazon EC2 instance configurations, which is an important consideration for data-intensive Web 2.0 applications.

Perancangan Sistem Informasi Parkir dengan WiFi Berbasis Arduino

Now the need for access to information is very important because the information obtained can specify or provide comfort and ease in performing daily activities. One example is to use gadgets such as smartphones, notebooks, tablets and others, we can easily find out information directly without having to come to the venue. This system aims to design information systems in the parking lot. This technology can provide an idea of ??the amount of available parking spots has been filled or empty. By accessing the IP address given earlier, then we will know the availability of parking space directly. From the test results, it can be said that this system has the advantages of easy to use, the application is simple and can help improve the comfort / convenience for users of the car park. But this system also has the disadvantage of a webserver which is used has a very small memory that can not be accessed by many concurrent users in one time.

Project anywhere: An interface for virtual architecture

Virtual and augmented realities open a new world of great potential for spatial research and experimentation by allowing new forms of unbuilt sensible architectural space. This article starts with a sketch of the current context in virtual reality and continues by outlining the development and structure of the research ‘project Anywhere’. The project is an easily deployable, wireless, multi-user, augmented reality app system that offers full body immersion through body, head and hands tracking. It can host multiple concurrent users, able to move freely in the virtual space, by moving in the real and also perform actions through a gesture interface to affect their shared environment. In conclusion, we describe the inherent properties of such a space, which we propose as a novel spatio-temporal medium for architecture that suggests an enriched notion of space for exploration and experimentation, through an example of a potential application.

Correlates of Concurrent Khat and Tobacco Use in Yemen

ABSTRACTBackground: Habitual substance use poses public health threat. This is a growing concern in countries where one or more substances are commonly used. Many individuals in Middle Eastern and East African countries use khat (Catha edulis), a stimulant often accompanied by smoking. However, few systematic attempts have been made to characterize patterns of concurrent khat and tobacco use. Objectives: To examine correlates such as gender and patterns of khat and tobacco use in concurrent users and khat-only users. Methods: This study used a cross-sectional design with a face-to-face interview method including 151 (74 women) concurrent users of khat and tobacco and 141 (76 women) khat-only users in Yemen. Data collection was completed in 2012. Analysis of variance (ANOVA) and logistic regressions were conducted to examine gender and khat use group differences in use patterns. Results: Reported frequency and intensity of khat use were greater in men than in women. Men and women khat users used different tobacco products and beverages while using khat. Khat use was more frequent in concurrent users relative to khat-only users. Earlier age of onset of khat use was associated with greater number of cigarettes smoked during a typical khat session. Approximately 70% of concurrent users reported initiating khat use prior to tobacco use. Conclusions/Importance: The results provide support for gender differences in khat and tobacco use, differences in khat use pattern between concurrent users of khat and tobacco and khat-only users, and positive associations between khat and tobacco use.

Intrusion detection and prevention of web service attacks for software as a service: Fuzzy association rules vs fuzzy associative patterns

Cloud computing inherits all the systems, networks as well asWeb Services’ security vulnerabilities, in particular for software as a service (SaaS), where business applications or services are provided over the Cloud as Web Service (WS). Hence, WS-based applications must be protected against loss of integrity, confidentiality and availability when they are deployed over to the Cloud environment. Many existing IDP systems address only attacks mostly occurring at PaaS and IaaS. In this paper, we present our fuzzy association rule-based (FAR) and fuzzy associative pattern-based (FAP) intrusion detection and prevention (IDP) systems in defending against WS attacks at the SaaS level. Our experimental results have validated the capabilities of these two IDP systems in terms of detection of known attacks and prediction of newvariant attacks with accuracy close to 100%. For each transaction transacted over the Cloud platform, detection, prevention or prediction is carried out in less than five seconds. For load and volume testing on the SaaS where the system is under stress (at a work load of 5000 concurrent users submitting normal, suspicious and malicious transactions over a time interval of 300 seconds), the FAR IDP system provides close to 95% service availability to normal transactions. Future work involves determining more quality attributes besides service availability, such as latency, throughput and accountability for a more trustworthy SaaS.

Concurrent self-use of Herbal and Synthetic Medicines in Kurdistan Region-Iraq.

In many parts of the world, there are rich traditions for the use of herbs in treatment of
 many disorders. This study is compared self-use of concurrent medicines (herbal and
 synthetic) (CM) with herbal only medicines (HM) among people of different genders,
 ages, and education levels in Kurdistan Region major cities (Erbil, Suleimaniyah, and
 Duhok). Self-administered structured questionnaires were randomly distributed among
 587 respondents. The information obtained comprises the demography, gender, age,
 education level, previous self-use of CM or HM and indications for which HM were
 used.The highest ratio of respondents were males (50.6 %), herbal and concurrent
 medicines users were (15.8%) and (84.2 %) respectively. In all age groups, ratio of
 concurrent medicines users were higher than herbal medicines (p< 0.05), age groups of
 31-40 and 51-60 years showed higher ratio among respondents with (23.5%) and
 (94.3%) for herbal and concurrent medicines, respectively. Among users of different
 educational levels, ratio of concurrent medicines were higher than herbal medicines (p<
 0.01), university graduate and primary school educational levels were with higher ratio
 of (33.9%) and (93.9%) for herbal and concurrent medicines, respectively. The highest
 percentage of herb users was among people who suffered from gastrointestinal problems
 (59%), respiratory tract (39%) and cardiovascular system problems (36%), while
 musculoskeletal conditions were less often treated with herbs in Kurdistan Region (9%).
 Almost 104 plant species were mentioned during the interviews with respondents
 belonging to 57 families, the most diverse one Umbelliferae, followed by Brassicaceae,
 Asteraceae and Rosaceae.

Alcohol consumption and corresponding factors: A novel perspective on the risk factors of esophageal cancer

Esophageal cancer is the eighth most common type of cancer in the world, and the sixth most common cause of mortality from cancer. Alcohol consumption is the major risk factor for esophageal cancer, due to the worldwide prevalence and high carcinogenicity of the ethanol metabolite. In epidemiological studies, the efficiency of alcohol intake to enhance the risk of esophageal cancer is altered by daily ethanol consumption, type of alcoholic beverages ingested, time since quitting drinking, age of drinking initiation, differences in population and subtypes of esophageal cancer. Corresponding factors, including gene polymorphisms, tobacco smoking, oral microorganisms and folate deficiency, reveal a synergistic effect in concurrent alcohol users that may lead to an increased risk of developing esophageal cancer. Consequently, esophageal cancer prevention involves multiple aspects, including quitting drinking and smoking, maintaining an adequate oral health and ingesting adequate quantities of folate, particularly in genetically high-risk populations.

Factors Associated With Concurrent Tobacco Smoking and Heavy Alcohol Consumption Within a Socioeconomically Disadvantaged Australian Sample

ABSTRACT Background: Tobacco use and heavy alcohol consumption occur more frequently in socioeconomically disadvantaged groups. Little is known about the sociodemographic and psychosocial factors associated with use of alcohol and tobacco in disadvantaged groups in comparison to low-risk users. Objectives: This study aimed to compare the characteristics of low-risk users with: disadvantaged smokers only; disadvantaged heavy drinkers only; and disadvantaged concurrent smokers and heavy drinkers. Methods: A cross-sectional survey of socioeconomically disadvantaged adult clients attending a community welfare agency assessed tobacco use, alcohol use, demographic, and psychosocial variables. Multivariable analysis using multinomial logistic regression was carried out. Results: The sample consisted of 835 participants; 40% (n = 331) were concurrent users, 31% were smokers only (n = 252), 11% were heavy drinkers only (n = 93), and 18% were low-risk users (n = 149). Compared with those who neither smoked nor consumed alcohol heavily, concurrent users were more likely to be younger, have only some contact with family, have more friends and family who were smokers, have no fixed home address, live alone, and have higher levels of financial stress. Most of these factors were shared by individuals who were smokers only. Factors associated with heavy drinkers only were frequent contact with family and having more friends and family who were smokers. Conclusion: Among those Australians who suffer severe economic hardship, being a concurrent smoker and heavy drinker appears to be associated with more isolated living conditions and financial stress but some contact with family.

R-extreme signalling for congestion control

ABSTRACTIn many ‘smart city’ applications, congestion arises in part due to the nature of signals received by individuals from a central authority. In the model of Mareček et al., each agent uses one out of multiple resources at each time instant. The per-use cost of a resource depends on the number of concurrent users. A central authority has up-to-date knowledge of the congestion across all resources and uses randomisation to provide a scalar or an interval for each resource at each time. In this paper, the interval to broadcast per resource is obtained by taking the minima and maxima of costs observed within a time window of length r, rather than by randomisation. We show that the resulting distribution of agents across resources also converges in distribution, under plausible assumptions about the evolution of the population over time.

Computer Adaptive Testing and Cloud Computing

Computer Adaptive Testing (CAT) is an example of a Com- puter Based Test (CBT) and is one of the main trending topics in the area of knowledge testing and, more recently, in e{learning or in Intelligent Tutoring Systems scenarios. The Item Response Theory (IRT) denes the theoretical basis of a CAT implementation, which assumes the existence of a repository of properly calibrated items that is used during the testing process of a particular examinee. The calibration and adaptation are based on an Item Characteristic Curve (ICC) related to an specic model, being Rasch's models the most widely used. CAT systems require high computational cost to implement the calibration and evaluation processes and the amount of concurrent users at a time could be large enough. Thus, the platform must support high concurrency and availability to perform a desired level of functionality. Technological tendencies in computing oer each time better platforms to develop and manage big collections of data for its processing and relevant information extraction. This paper presents a perspective of using new technologies in CAT as an alternative of implementation. Particularly, the use of a cloud computing platform as current alternative for online CAT systems using the capabilities of multicore processing and big amount of RAM that oers the cloud, to resolve the proper mathematical equations related to psychometric models and the operations described in their algorithms in a real evaluation scheme.

Construction of Server for Developing Game Engine, Using Node.js+Nginx

SNG(Social Network Game)의 경우 동시에 접속하는 사용자 수가 많이 발생하게 된다. 이 경우 서비스 품질을 유지하기 위해서는 사용자 수에 비례하게 서버의 CPU와 메모리를 늘려 주어야 한다. 이러한 문제점을 해결하기 위해 "Nginx"와 "Node.js"를 결합하여 비동기 방식의 서버를 개발하였다. 개발된 서버의 성능 평가는 RF-ONLINE 모바일 게임을 개발하여 정보산업 성능평가 지침 기준을 적용하여 동시접속자 수 5%의 처리 능력을 평가 하였다. 그 결과 본 논문에서 제안한 서버의 경우 동시 접속자 수의 5%를 처리하기 위해 추가적인 하드웨어의 증설 없이도 양질의 서비스가 가능하였으며, 아파치 서버와 개발한 서버를 비교한 결과 동시접속자수 1,300명을 기준으로 아파치 + Node.js : 6,021ms, Nginx +Node.js : 2,841ms의 응답시간을 기록하여 1.8배의 비용 절감이 가능함을 확인하였다. Social Network Game is generated a lot of number of users connected at the same time. In this case, the CPU and memory of the server should increase in proportion to the number of users in order to maintain the service quality. To solve this problem, the asynchronous method server that implements a combination of "Nginx" and "Node.js". Performance Evaluation of a development server was done by developing RF-ONLINE mobile games. The proposed concurrent users a server can also generate 5% of capacity without additional hardware quality services were available to. As its result, in case of server proposed in this thesis, it is possible to provide excellent service without increasing additional hardware to deal with 5% of concurrent connected users, and as a result of comparison between Apache server and developed server, we confirmed that it is possible to save cost by 1.8 times as respond time of Apache+Node.js being recorded as 6,021ms and that of Nginx+Node.js as 2,841ms based on 1,300 persons of concurrent connected user.

Asthma Controller Medication Adherence, Risk of Exacerbation, and Use of Rescue Agents Among Texas Medicaid Patients with Persistent Asthma.

Adherence to asthma long-term controller medications is one of the key drivers to improve asthma management among patients with persistent asthma. While suboptimal use of controller medications has been found to be associated with more frequent use of oral corticosteroids (OCS), few studies exist regarding the relationship between adherence to controller therapy and the use of short-acting beta2-agonists (SABAs). A better understanding of the association between adherence to asthma controller agents and use of reliever medications will help health care providers and decision makers enhance asthma management. To determine if there is a relationship between asthma controller adherence, risk of exacerbation requiring OCS, and use of asthma rescue agents. Texas Medicaid claims data from January 1, 2008, to August 31, 2011, were retrospectively analyzed. Continuously enrolled patients aged 5-63 years with a primary diagnosis of asthma (ICD-9-CM code 493) and with 4 or more prescription claims for any asthma medication in 1 year (persistent asthma) were included. The index date was the date of the first asthma controller prescription, and patients were followed for 1 year. The primary outcome variables were SABA (dichotomous: less than 6 vs. ≥ 6) and OCS (continuous) use. The primary independent variable was adherence (proportion of days covered [PDC]) to asthma long-term controller medications. Covariates included demographics and nonstudy medication utilization. Multivariate logistic and linear regression analyses were employed to address the study objective. The study sample (n = 32,172) was aged 15.0 ± 14.5 years, and adherence to controller therapy was 32.2% ± 19.7%. The mean number of SABA claims was 3.7 ± 3.1, with most patients having 1-5 claims (73.2%), whereas 19.4% had ≥ 6 SABA claims. The mean number of OCS claims was 1.0 ± 1.4. Adherent (PDC ≥ 50%) patients were 96.7% (OR = 1.967; 95% CI = 1.826-2.120) more likely to have ≥ 6 SABA claims when compared with nonadherent (PDC less than 50%) patients (P less than 0.001). As for OCS use, adherent patients had 0.11 fewer claims compared with nonadherent patients (P less than 0.001). Importantly, patients with ≥ 6 SABA claims had 0.7 more OCS claims compared with patients with less than 6 claims for SABA (P less than 0.001). The odds of having ≥ 6 SABA claims were higher for concurrent dual therapy users, older age, males, African Americans and higher number of nonstudy medications (P less than 0.001). Dual therapy users, younger age, Hispanic ethnicity, and higher number of nonstudy medications were associated with an increase in OCS use (P less than 0.005). Adherence to long-term controller medications was suboptimal among patients with asthma. Adherent patients had fewer OCS claims, indicating that adherence to controller therapy is critical in preventing asthma exacerbations requiring OCS use. Although there was a positive relationship between adherence to long-term controller medication and SABA use, increased SABA use served as a predictor of increased OCS use, which indicates poor asthma control. Health care providers should be aware of OCS and SABA use among patients who are both adherent and nonadherent to asthma controller medications.

Scale out databases for CERN use cases

Data generation rates are expected to grow very fast for some database workloads going into LHC run 2 and beyond. In particular this is expected for data coming from controls, logging and monitoring systems. Storing, administering and accessing big data sets in a relational database system can quickly become a very hard technical challenge, as the size of the active data set and the number of concurrent users increase. Scale-out database technologies are a rapidly developing set of solutions for deploying and managing very large data warehouses on commodity hardware and with open source software. In this paper we will describe the architecture and tests on database systems based on Hadoop and the Cloudera Impala engine. We will discuss the results of our tests, including tests of data loading and integration with existing data sources and in particular with relational databases. We will report on query performance tests done with various data sets of interest at CERN, notably data from the accelerator log database.

Reducing drinking in concurrent problem alcohol and illicit drug users: an impact story

Objective To inform addiction treatment in primary care with respect to psychosocial interventions to reduce drinking in concurrent problem alcohol and illicit drug users, by: exploring the experience of (and evidence for) psychosocial interventions, developing and evaluating a complex intervention to improve implementation. Evaluation of the intervention tested core feasibility and acceptability outcomes for patients and providers.

The impact of decision support system features on user overconfidence and risky behavior

There is considerable research on how Decision Support Systems (DSSs) enable users to make better decisions. However, there is less focus on the possibility that some of their features may introduce biases and encourage suboptimal user behavior. We report on an experimental study that examines three DSS features that are generally considered beneficial to the user: the degree of choice the system provides to the user, the presence of competition among concurrent users, and the use of training to increase system familiarity. We hypothesize that the three DSS features may increase risky behavior (measured as the amount invested in a stock investment task with random outcomes) and overconfidence, conceptualized as the illusion of control, the phenomenon whereby people believe their chances of success at a task are greater than would be warranted by objective analysis. Our results confirm the effects of the three DSS features on risky behavior but only degree of choice impacts overconfidence. Moreover, overconfidence does not appear to mediate the impact of the DSS features on risky behavior. Finally, we hypothesize and confirm that, controlling for the effect of actual performance, overconfidence increases user satisfaction with the decision-making process and outcome.

The next-generation in-stadium experience (keynote)

YinzCam is a cloud-hosted service that provides sports fans with real-time scores, news, photos, statistics, live radio, streaming video, etc., on their mobile devices. YinzCam’s infrastructure is currently hosted on Amazon Web Services (AWS) and supports over 30 million installs of the official mobile apps of 140+ NHL/NFL/NBA/NRL/NCAA sports teams and venues. YinzCam’s workload is necessarily multi-modal (e.g., pre-game, in-game, post-game, game-day, non-gameday), with normal game-time traffic being twenty-fold of that on non-game days. This paper describes the evolution of YinzCam’s production architecture and distributed infrastructure, from its beginnings in 2009, when it was used to support thousands of concurrent users, to today’s system that supports millions of concurrent users on any game day. We also discuss key new opportunities to improve the fan experience inside the stadium of the future, without impacting the available bandwidth, by crowd-sourcing the thousands of mobile devices that are in fans’ hands inside these venues. We present Krowd, a novel distributed key-value store for promoting efficient content sharing, discovery and retrieval across the mobile devices inside a stadium. We present CHIPS, a system that ensures that users’ privacy is maintained while their devices participate in the crowdsourced infrastructure.