Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency–Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research

The use of WMC distribution for performance evaluation of APD optical communication systems

In the analysis of the bit-error rate (BER) of an optical communication system with avalanche photodiode (APD) detectors, the Webb, McIntyre, Conradi (WMC) distribution has been often used to approximate the APD receiver output statistics, This paper presents new simple and closed form BER expressions as well as an importance sampling technique for optical systems employing APD receivers when the WMC model is used. Comparison of the WMC model with the exact model is also carried out, In particular, it is shown that the WMC distribution is quite accurate and has the advantage of simplicity for both simulation and analysis

A new multiuser detector for optical code division multiple access communications systems

Optical code division multiple access has been proposed as an alternative multiple access scheme for multiuser fiber-optic communication systems, Many previous works on the receivers for such systems have focused on the correlation receiver which is optimal in the single user case. However, it has been shown that the performance of the correlation receiver is unsatisfactory when there is a large number of interferers, Multiuser detection becomes an appealing method to improve the system performance, In this paper, a new multiuser detector for optical code division multiple access communication systems, referred to as the multistage decorrelating receiver, is proposed, Its structure is much simpler than the optimal multiuser detector at the expense of slight performance degradation, Both simulation and analysis of the receiver are carried out, Comparison of the proposed detector with several other receivers is also presented

Optical CDMA communication systems with multiuser and blind detection

In this paper, we study the use of multiuser detection and blind detection techniques to improve the performance of optical code-division multiple-access (OCDMA) systems. First, a new multiuser receiver known as the interference suppression receiver is proposed. Second, we study the use of blind detection by proposing a blind receiver for OCDMA systems. While previous studies on multiuser detection are limited to systems with p-i-n detectors, avalanche photodiode detectors are also included here

A blind receiver for optical code division multiple access communications systems

The application of code division multiple access (CDMA) techniques to a fiber-optic communication systems has aroused much interest. The simplest receiver is the correlation receiver but its performance deteriorates rapidly as the number of users increases, Thus, it is highly desirable to have a better receiver structure for such systems, Many multiuser detection schemes have been proposed, However, multiuser detectors require knowledge of some parameters such as the signature sequence of other users. It would thus be a great advantage if this requirement can be removed, In this paper, we propose a blind receiver that does not require knowledge of the users' system parameters except for those of the desired user. Thereby, significantly reducing the receiver complexity is possible, Performance of the proposed receiver is investigated and comparison of several receivers for OCDMA systems is also presented

Mechanistic, mechanistic-based empirical, and continuum-based concepts and models for the transport of polyelectrolyte-modified nanoscale zerovalent iron (NZVI) in saturated porous media

Controlled emplacement of polyelectrolyte-modified NZVI at a high particle concentration (1–10 g/L) is needed for effective in situ subsurface remediation. For this reason, a modeling tool capable of predicting polyelectrolyte-modified NZVI transport is imperative. However, the deep bed filtration theory is invalid for this purpose because several phenomena governing the transport of polyelectrolyte-modified NZVI in saturated porous media, including detachment, particle agglomeration, straining, and porous media ripening, violate the fundamental assumption of such a classical theory. Thus, this chapter critically reviews the literature of each phenomenon with various kinds of nanoparticles with a special focus on polyelectrolyte-modified NZVI. Then, each phenomenon is elaborated using three kinds of mathematical models, including mechanistic (such as extended DLVO theory), mechanistic-based empirical (correlations to predict NZVI agglomeration and deposition), and continuum-based (Eulerian continuum-based models). These proposed modeling tools can be applied at various scales from column experiments (1-D) to field-scaled operations (3-D) for designing NZVI injection and emplacement in the subsurface