Pegasus Research Impact
Today’s science is built on the shoulders of research software. The Pegasus workload management system (est. 2001) has significantly contributed to the scientific progress in several domains including astronomy, Earth science, climate science, bioinformatics, neuroinformatics, among others. In order to quantify how Pegasus has impacted the scientific community, we constantly perform data analysis on publications and citations data provided by online services such as Google Scholar.
The goal of this page is to report the state-of-the-art research impact provided by the Pegasus software. To this end, we use the open-source CitationXpert software to apply data science methods to extract metric values that quantify the research impact of the Pegasus software.
This analysis is based on citations for the two main Pegasus publications (see below), and references to the Pegasus’ website extracted from Google Scholar.
Number of Citations
Distribution of Citation Types
Distribution of Authors Citing PegasusView Larger Map
- E. Deelman, K. Vahi, G. Juve, M. Rynge, S. Callaghan, P. J. Maechling, R. Mayani, W. Chen, R. Ferreira da Silva, M. Livny, and K. Wenger, “Pegasus: a Workflow Management System for Science Automation,” Future Generation Computer Systems, vol. 46, pp. 17-35, 2015.
- E. Deelman, G. Singh, M. Su, J. Blythe, Y. Gil, C. Kesselman, G. Mehta, K. Vahi, B. G. Berriman, J. Good, A. Laity, J. C. Jacob, and D. S. Katz, “Pegasus: a Framework for Mapping Complex Scientific Workflows onto Distributed Systems,” Scientific Programming Journal, vol. 13, iss. 3, pp. 219-237, 2005.
Pegasus has been cited in 1121 research articles, where 175 of these citations are done by one of the authors from the two Pegasus’ articles (named self-reference), and 946 are external references—cited by other scientists/researchers. Although several research studies and application support has been internally developed within the Pegasus team, the ratio of self-reference citations is limited to about 15% of the total number of citations. This result demonstrates the overall impact of the Pegasus software within the research community.
We break down the total number of citations per year to observe the evolution of citations since the first publication of the Pegasus software (in 2005). The number of self-references per year is nearly constant with an average value of 14.6 citations (standard deviation 4.4), while there is an increase on the number of external references per year. The significant increase on the number of citations in 2015 (when the second Pegasus software paper was published), demonstrates the importance (and impact) of up-to-date research articles to the research community. In 2016, the number of references is still low because the data was collected on June (only 6 months of citations).
The distribution of citation types is based on the analysis of BibTex entry types. We measure the distribution of citation types (entry types) per year for self-referenced and external references. Within the SciTech research group (which develops Pegasus), there is a balance between the number of citations from publications published in conferences (In Proceedings or In Collection) and in journal articles (46.6% in average, standard deviation 12.2%), with a tendency to the prevalence of journal articles in the past few years. The list of publications are available on the SciTech website.
External references present a clear tendency for the prevalence of journal articles along the years (average increase rate 1.17, standard deviation 0.23). This result may indicate that research developed in the early stages (which are often first published in conferences), continue to evolve and become more mature, leading to journal article publications. Since the number of references increase for each year, this result also allows to infer that new research continues to be developed using the Pegasus software. The important number of PhD thesis referencing the Pegasus highlights the importance of the software to the research community (average 6.9%, standard deviation 1.8%).
The h-index quantifies the research output of an individual. The metric software-h-index indicates then that a software has index h if its citations (research articles citing the software) have at least h citations each. This metric measures the second-tier degree impact of the software in other researches. The current software-h-index for Pegasus is 66.
Pegasus has been cited by 2592 different authors. Then, we gathered the authors information from Google Scholar to determine the impact of the Pegasus software worldwide. Although Google Scholar is a very popular tool for tracking individual citations, only a fraction of the authors have a profile (837 authors out of 2592). Using the registered author email, we can determine the location of the authors’ institutions. The map below shows the distribution of authors citing the Pegasus software since 2005. Most of the authors are from the USA (353 authors), followed by the United Kingdom (70 authors), China (43 authors), Australia (26 authors), and France (24 authors). Please see the enlarged map for detailed information.
In Greek mythology, Pegasus was the son of Poseidon and Medusa, having sprung from the blood of Medusa as it dropped into the sea after her head was severed by Perseus. He was captured by Bellerophon at the water of his fountain and was ridden by him when he killed Chimera. Bellerophon showed disrespect to the Gods as he attempted to ride Pegasus to Mount Olympus and Zeus sent an insect to sting Pegasus and Bellerophon was thrown back. Pegasus found sanctuary on the sacred mountain, where he carried Zeus' thunderbolts and was ridden by Eos, the goddess of dawn. Under his feet sprang the sacred springs of the Muses on Mount Helicon.
Many cultures, religions, and pieces of literature contain similar magical horses. The Buraq, according to Islamic tradition, is a creature from the heavens that carried Muhammad from earth to heaven and back. Chollima is the Korean name for a mythical horse that is said to be too swift to be mounted. In Norse mythology, Sleipnir is Odin's magical eight-legged steed, and said to be the greatest of all horses. In all of these examples, the horses are good, and are helpful, just like in the Greek mythology version of Pegasus. This is not always the case. In Harry Potter, Thestrals are the most elusive and least horse-like breed of magical horse. They have earned an undeserved reputation as omens of evil, and can only be seen when a person has experienced and accepted a death. The horses are scary looking, but are extremely gentle and helpful once one gets to know them.
Not only in Harry Potter, examples and allusions of Pegasus can be seen in many aspects of modern society. Luno the White Stallion was a Terry Toons television series that aired in the mid-1960s. It centered on a little boy named Tim who had a marble Pegasus horse named Luno who would come alive and whisk him off on adventures in far off lands when Tim said the words, "Oh winged horse of marble white, take me on a magic flight". (www.wikipedia.com/luno). In this example, TimÐ²Ð‚™s marble horse directly relates to Greek mythologyÐ²Ð‚™s version of Pegasus. In Greek mythology, Pegasus was used to go on adventures, and here in the cartoon, Luno took Tim on adventures.
In modern society, Pegasus can be seen on many logos, and is apart of many company names. When a company chooses Pegasus to represent them, itÐ²Ð‚™s probably because in todayÐ²Ð‚™s society, Pegasus is synonymous with power and strength, because he was chosen to carry ZeusÐ²Ð‚™ lightning bolts, a position that required both power and strength, among other qualities.
Pegasus can be seen as the logo of Mobil gas and oil. In the logo, there is a red horse with wings. Mobil used Pegasus on purpose, because Pegasus resembles power and strength. They want to convey this message when the public chooses a type of gas. They want the public to choose their gas because once consumers see MobilÐ²Ð‚™s logo; Mobil hopes the consumer will be able to associate their gas with powerfulness, and MobilÐ²Ð‚™s ability to successfully power the car.
Pegasus is also the logo of Tri-Star Pictures, a subsidiary of Columbia Pictures. In their logo, we see a picture of a dreamy, sun-lit area full of clouds. A bright light flashes from the bottom center of the screen to reveal a white, winged Pegasus walking on the clouds. In bold, golden lettering, "TRISTAR" appears on the top of the screen. In this logo as well, Pegasus is used to convey powerfulness. Tri-star not only hopes that consumers will associate their pictures as powerful, meaningful movies, but also as movies that capture one's