683 research outputs found
Fraud in Commodity Futures Trading--An Examination of the Investor\u27s Remedies
This Note examines the various avenues of redress available to the defrauded commodity futures investor. Initially, an examination of two remedies expressly provided in the Commodity Exchange Act (CEA)--reparations and arbitration--demonstrates their current inefficiencies and inadequacies. Next, the Note considers the possibility of recovery under the antifraud provision of the Securities Exchange Act and argues that such a cause of action should still be available when the investor can show that the particular discretionary trading account is a security. Finally, a discussion of an implied private right of action for violations of the antifraud provision of the CEA reveals much confusion and dispute about its existence and concludes that it should not be permitted at the present time. Ultimately, this Note suggests that the uncertainty surrounding these possible methods of recovery demands that Congress give further consideration to these issues
Adversarial attacks on crowdsourcing quality control
Crowdsourcing is a popular methodology to collect manual labels at scale. Such labels are often used to train AI models and, thus, quality control is a key aspect in the process. One of the most popular quality assurance mechanisms in paid micro-task crowdsourcing is based on gold questions: the use of a small set of tasks of which the requester knows the correct answer and, thus, is able to directly assess crowd work quality. In this paper, we show that such mechanism is prone to an attack carried out by a group of colluding crowd workers that is easy to implement and deploy: the inherent size limit of the gold set can be exploited by building an inferential system to detect which parts of the job are more likely to be gold questions. The described attack is robust to various forms of randomisation and programmatic generation of gold questions. We present the architecture of the proposed system, composed of a browser plug-in and an external server used to share information, and briefly introduce its potential evolution to a decentralised implementation. We implement and experimentally validate the gold detection system, using real-world data from a popular crowdsourcing platform. Our experimental results show that crowd workers using the proposed system spend more time on signalled gold questions but do not neglect the others thus achieving an increased overall work quality. Finally, we discuss the economic and sociological implications of this kind of attack
All That Glitters is Gold -- An Attack Scheme on Gold Questions in Crowdsourcing
One of the most popular quality assurance mechanisms in paid micro-task crowdsourcing is based on gold questions: the use of a small set of tasks of which the requester knows the correct answer and, thus, is able to directly assess crowd work quality. In this paper, we show that such mechanism is prone to an attack carried out by a group of colluding crowd workers that is easy to implement and deploy: the inherent size limit of the gold set can be exploited by building an inferential system to detect which parts of the job are more likely to be gold questions. The described attack is robust to various forms of randomisation and programmatic generation of gold questions. We present the architecture of the proposed system, composed of a browser plug-in and an external server used to share information, and briefly introduce its potential evolution to a decentralised implementation. We implement and experimentally validate the gold detection system, using real-world data from a popular crowdsourcing platform. Finally, we discuss the economic and sociological implications of this kind of attack
Search behaviour before and after search success
Why do users continue searching after reviewing all relevant documents with which they could have completed a work task? If we knew the answer, then a search system may be able to help users learn about their current search processes, which in turn may enable them to make the whole search process more efficient, leading to greater effectiveness and user satisfaction. This paper is a first step towards solving this problem. Using a previously collected data set, we identified the point of success and hence task completion, and investigated the search behaviour before and after users had accessed all relevant documents for answering assigned tasks. We used a set of search behaviour actions derived from Marchionini's (1995) Information Seeking Process model, and modeled the distribution of these actions throughout the entire search process, comparing actions before and after success could have been attained. Our results suggest that six defined actions, namely user-submitted query, system-suggested query, forward to items, evaluate relevant items, reflect, and answer appeared to change according to the stage of the entire search process. Also, users have notably distinct patterns before and after search success was obtained, but not realised by the user. Not all action were affected; user-submitted query and system-suggested query appeared to be unaffected by time in post-success case and presuccess case, respectively
Generation of Antibunched Light by Excited Molecules in a Microcavity Trap
The active microcavity is adopted as an efficient source of non-classical light. By this device, excited by a mode-locked laser at a rate of 100 MHz, single-photons are generated over a single field mode with a nonclassical sub-poissonian distribution. The process of adiabatic recycling within a multi-step Franck-Condon molecular optical-pumping mechanism, characterized in our case by a quantum efficiency very close to one, implies a pump self-regularization process leading to a striking n-squeezing effect. By a replication of the basic single-atom excitation process a beam of quantum photon (Fock states) can be created. The new process represents a significant advance in the modern fields of basic quantum-mechanical investigation, quantum communication and quantum cryptography
A Review of Production Planning Models: Emerging features and limitations compared to practical implementation
In the last few decades, thanks to the interest of industry and academia, production planning (PP) models have shown significant growth. Several structured literature reviews highlighted the evolution of PP and guided the work of scholars providing in-depth reviews of optimization models. Building on these works, the contribution of this paper is an update and detailed analysis of PP optimization models. The present review allows to analyze the development of PP models by considering: i) problem type, ii) modeling approach, iii) development tools, iv) industry-specific solutions. Specifically, to this last point, a proposed industrial solution is compared to emerging features and limitations, which shows a practical evolution of such a system
CrowdCO-OP : sharing risks and rewards in crowdsourcing
Paid micro-task crowdsourcing has gained in popularity partly due to the increasing need for large-scale manually labelled datasets which are often used to train and evaluate Artificial Intelligence systems. Modern paid crowdsourcing platforms use a piecework approach to rewards, meaning that workers are paid for each task they complete, given that their work quality is considered sufficient by the requester or the platform. Such an approach creates risks for workers; their work may be rejected without being rewarded, and they may be working on poorly rewarded tasks, in light of the disproportionate time required to complete them. As a result, recent research has shown that crowd workers may tend to choose specific, simple, and familiar tasks and avoid new requesters to manage these risks. In this paper, we propose a novel crowdsourcing reward mechanism that allows workers to share these risks and achieve a standardized hourly wage equal for all participating workers. Reward-focused workers can thereby take up challenging and complex HITs without bearing the financial risk of not being rewarded for completed work. We experimentally compare different crowd reward schemes and observe their impact on worker performance and satisfaction. Our results show that 1) workers clearly perceive the benefits of the proposed reward scheme, 2) work effectiveness and efficiency are not impacted as compared to those of the piecework scheme, and 3) the presence of slow workers is limited and does not disrupt the proposed cooperation-based approaches
Towards building a standard dataset for Arabic keyphrase extraction evaluation
Keyphrases are short phrases that best
represent a document content. They can be useful
in a variety of applications, including document
summarization and retrieval models. In this paper,
we introduce the first dataset of keyphrases for an
Arabic document collection, obtained by means of
crowdsourcing. We experimentally evaluate different
crowdsourced answer aggregation strategies and
validate their performances against expert annotations
to evaluate the quality of our dataset. We
report about our experimental results, the dataset
features
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The Thiol-Rich Interlayer in the Shell/Core Architecture of Mussel Byssal Threads.
The mussel byssus thread is an extremely tough core-shelled fiber that dissipates substantial amounts of energy during tensile loading. The mechanical performance of the shell is critically reliant on 3,4-dihydroxyphenylalanine's (Dopa) ability to form reversible iron-catecholate complexes at pH 8. However, the formation of these coordinate cross-links is undercut by Dopa's oxidation to Dopa-quinone, a spontaneous process at seawater conditions. The large mechanical mismatch between the cuticle and the core lends itself to further complications. Despite these challenges, the mussel byssus thread performs its tethering function over long periods of time. Here, we address these two major questions: (1) how does the mussel slow/prevent oxidation in the cuticle, and (2) how is the mechanical mismatch at the core/shell interface mitigated? By combining a number of microscopy and spectroscopy techniques we have discerned a previously undescribed layer. Our results indicate this interlayer is thiol rich and thus will be called the thiol-rich interlayer (TRL). We propose the TRL serves as a long-lasting redox reservoir as well as a mechanical barrier
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