Performance scalability analysis of JavaScript applications with web workers

Web applications are getting closer to the performance of native applications taking advantage of new standard–based technologies. The recent HTML5 standard includes, among others, the Web Workers API that allows executing JavaScript applications on multiple threads, or workers. However, the internals of the browser’s JavaScript virtual machine does not expose direct relation between workers and running threads in the browser and the utilization of logical cores in the processor. As a result, developers do not know how performance actually scales on different environments and therefore what is the optimal number of workers on parallel JavaScript codes. This paper presents the first performance scalability analysis of parallel web apps with multiple workers. We focus on two case studies representative of different worker execution models. Our analyses show performance scaling on different parallel processor microarchitectures and on three major web browsers in the market. Besides, we study the impact of co–running applications on the web app performance. The results provide insights for future approaches to automatically find out the optimal number of workers that provide the best tradeoff between performance and resource usage to preserve system responsiveness and user experience, especially on environments with unexpected changes on system workload.Peer ReviewedPostprint (author's final draft

Reliable Crowdsourcing for Multi-Class Labeling using Coding Theory

Crowdsourcing systems often have crowd workers that perform unreliable work on the task they are assigned. In this paper, we propose the use of error-control codes and decoding algorithms to design crowdsourcing systems for reliable classification despite unreliable crowd workers. Coding-theory based techniques also allow us to pose easy-to-answer binary questions to the crowd workers. We consider three different crowdsourcing models: systems with independent crowd workers, systems with peer-dependent reward schemes, and systems where workers have common sources of information. For each of these models, we analyze classification performance with the proposed coding-based scheme. We develop an ordering principle for the quality of crowds and describe how system performance changes with the quality of the crowd. We also show that pairing among workers and diversification of the questions help in improving system performance. We demonstrate the effectiveness of the proposed coding-based scheme using both simulated data and real datasets from Amazon Mechanical Turk, a crowdsourcing microtask platform. Results suggest that use of good codes may improve the performance of the crowdsourcing task over typical majority-voting approaches.Comment: 20 pages, 11 figures, under revision, IEEE Journal of Selected Topics in Signal Processin

Leadership Behaviour and Worker Performance in the Nigerian Construction Industry

Leadership is a dynamic process in which an individual influence other to contribute to the achievement of an assigned task. This paper investigates leadership behaviour and its impact on construction workers’ performance in Lagos, Nigeria. Purposive sampling technique was adopted to select 50 site-supervisors and 250 construction-workers involved in simple construction works. An investigation was carried out using a questionnaire survey method. The leadership variables investigated were ranked, regressed and correlated to workers performance. From the primary data analysis, leadership behaviour exhibited by supervisors were found to influence the site workers commitment to achieving the goal of the construction projects. The most exhibited leadership behaviour on the studied construction site is transformational leadership behaviour with an overall mean score of 4.09. There also exists a positive linear correlation of transactional leadership behaviour with construction workers performance. Findings revealed that the adoption of laissez-faire leadership behaviour results in negative correlation with construction workers performance. The study concludes that the success of construction projects depends on the project manager and its employees, therefore leadership qualities is an important skill that everyone in the construction industry should possess as it enhances the timely delivery of construction works

Multi-object Classification via Crowdsourcing with a Reject Option

Consider designing an effective crowdsourcing system for an $M$-ary classification task. Crowd workers complete simple binary microtasks whose results are aggregated to give the final result. We consider the novel scenario where workers have a reject option so they may skip microtasks when they are unable or choose not to respond. For example, in mismatched speech transcription, workers who do not know the language may not be able to respond to microtasks focused on phonological dimensions outside their categorical perception. We present an aggregation approach using a weighted majority voting rule, where each worker's response is assigned an optimized weight to maximize the crowd's classification performance. We evaluate system performance in both exact and asymptotic forms. Further, we consider the setting where there may be a set of greedy workers that complete microtasks even when they are unable to perform it reliably. We consider an oblivious and an expurgation strategy to deal with greedy workers, developing an algorithm to adaptively switch between the two based on the estimated fraction of greedy workers in the anonymous crowd. Simulation results show improved performance compared with conventional majority voting.Comment: two column, 15 pages, 8 figures, submitted to IEEE Trans. Signal Proces

Social comparison in the workplace: evidence from a field experiment

We conducted a randomized field experiment to examine how workers respond to wage cuts, and whether their response depends on the wages paid to coworkers. Workers were assigned to teams of two, performed identical individual tasks, and received the same performance‐independent hourly wage. Cutting both team members’ wages caused a substantial decrease in performance. When only one team member’s wage was cut, the performance decrease for the workers who received the cut was more than twice as large as the individual performance decrease when both workers’ wages were cut. This finding indicates that social comparison processes among workers affect effort provision because the only difference between the two wage cut conditions is the other team member’s wage level. In contrast, workers whose wage was not cut but who witnessed their team member’s pay being cut displayed no change in performance relative to the baseline treatment in which both workers’ wages remained unchanged, indicating that social comparison exerts asymmetric effects on effort.Compensation, fairness, field experiment, social comparison

Do Salaries Improve Worker Performance?

We establish the effects of salaries on worker performance by exploiting a natural experiment in which some workers in a particular occupation (football referees) switch from short-term contracts to salaried contracts. Worker performance improves among those who move onto salaried contracts relative to those who do not. The finding is robust to the introduction of worker fixed effects indicating that it is not driven by better workers being awarded salary contracts. Nor is it sensitive to workers sorting into or out of the profession. Improved performance could arise from the additional effort workers exert due to career concerns, the higher income associated with career contracts (an efficiency wage effect) or improvements in worker quality arising from off-the-job training which accompanies the salaried contracts.

The Economic Pay-Offs To On-The-Job Training In Routine Service Work

This study examines the relationship between on-the-job training and job performance among 3,408 telephone operators in a large unionized telecommunications company. We utilize individual data on monthly training hours and job performance over a five-month period as provided by the company’s electronic monitoring system. Results indicate that the receipt of on-the-job training is associated with significantly higher productivity over time, when unobserved individual heterogeneity is taken into account. Moreover, workers with lower pre-training proficiency show greater improvements over time than those with higher pre-training proficiency. Finally, whether the training is provided by a supervisor or a peer also matters. Workers with lower proficiency achieve greater productivity gains through supervisor training, while workers with higher proficiency achieve greater productivity gains through peer training

Internal Promotion Competitions in Firms

[Excerpt] Using a sample of skilled workers from a cross section of establishments in four metropolitan areas of the United States, I present evidence suggesting that promotions are determined by relative worker performance. I then estimate a structural model of promotion tournaments (treating as endogenous promotions, worker performance, and the wage spread from promotion) that simultaneously accounts for worker and firm behavior and how the interaction of these behaviors gives rise to promotions. The results are consistent with the predictions of tournament theory that employers set wage spreads to induce optimal performance levels, and that workers are motivated by larger spreads

All Turnover Is Not Created Equal: Gaining Insight Into How Employee Departures Affect Organizational Units

[Excerpt] Key Findings: Traditional turnover ratios–the number of employees leaving versus the total number in a unit—may not accurately describe how employee departures affect business unit performance. Traditional measures of turnover focus primarily on the quantity of employee exits, but fail to measure important qualities of turnover events. Some turnover scenarios tend to be more damaging than others, such as if a unit loses proficient workers, loses workers all at once, gains relatively less proficient workers, or loses workers from core functions rather than peripheral ones. To effectively link turnover to performance, metrics should account for when employees leave and from which positions, and accurately reflect the capabilities of exiting, remaining, and entering employees. The authors propose a new measure of “capacity” that targets both the quantity and qualities of turnover, allowing practitioners to improve the information value of attrition-related metrics

Do Salaries Improve Worker Performance?

We establish the effects of salaries on worker performance by exploiting a natural experiment in which some workers in a particular occupation (football referees) switch from short-term contracts to salaried contracts. Worker performance improves among those who move onto salaried contracts relative to those who do not. The finding is robust to the introduction of worker fixed effects indicating that it is not driven by better workers being awarded salary contracts. Nor is it sensitive to workers sorting into or out of the profession. Improved performance could arise from the additional effort workers exert due to career concerns, the higher income associated with career contracts (an efficiency wage effect) or improvements in worker quality arising from off-the-job training which accompanies the salaried contracts.incentives, salaries, productivity, sports