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Topic Review
Edge Couplers
Silicon photonics has drawn increasing attention since recent decades and is promising to act as a key technology for future daily applications due to its various merits including ultra-low cost, high integration density owing to the high refractive index of silicon and compatibility with current semiconductor fabrication process. Optical interconnects is an important issue in silicon photonic integrated circuits to transmit light and fiber-to-chip optical interconnects is vital in application scenarios like data centers and optical transmission systems. There are mainly two categories of fiber-to-chip optical coupling, that is off-plane coupling and in-plane coupling. Grating couplers work under the former category while edge couplers function as in-plane coupling. In this paper, we mainly focus on edge couplers in silicon photonic integrated circuits. We deliver an introduction to the research background, operation mechanism and design principles of silicon photonic edge couplers. The state-of-the-art of edge couplers is reviewed according to different configurations as to the device structure, identifying the performance, fabrication feasibility and applications. In addition, a brief comparison between edge couplers and grating couplers is conducted. Packaging issue is also discussed and several prospective techniques for further improvements of edge couplers are proposed.
  • 8.1K
  • 27 Oct 2020
Topic Review
PSA XUD
The PSA XUD is a Diesel engine designed and built by PSA - Peugeot and Citroën. It is an Indirect injection (IDI) engine, that uses a version of the Ricardo Consulting Engineers Ricardo Comet V prechamber cylinder head design. The engine comes in 1.8 L (1,769 cc) N/A, 1.8 Turbo, 1.9 L (1,905 cc) N/A, Turbo, 2.1 12 valve N/A and Turbo and was the predecessor to the HDI range of engines. Early HDi Engines were a PSA design, later 16 valve engines were jointly developed with Ford.
  • 8.1K
  • 28 Oct 2022
Topic Review
Frogs in Culture
Frogs play a variety of roles in culture, appearing in folklore and fairy tales such as the Brothers Grimm story of The Frog Prince. In ancient Egypt and Mesopotamia, frogs symbolized fertility, while in classical antiquity, the Greeks and Romans associated frogs with fertility, harmony, and licentiousness. Frogs are the subjects of fables attributed to Aesop, of proverbs in various cultures, and of art. Frog characters such as Kermit the frog and Pepe the Frog feature in popular culture. They are eaten in some parts of the world including France. In Australia, a fondant dessert is known as frog cake.
  • 8.1K
  • 27 Nov 2022
Topic Review
Video Game Live Streaming
Video game live streaming is a kind of real-time video social media that integrates traditional broadcasting and online gaming. Real-time, sociability and suspense are the main features of video game live streaming. Video game live streaming can meet user demands in social integration, personal integration, tension release, affection, and cognition. In order to have a more comprehensive understanding of video game live streaming, the following text summarizes the background from the live streaming industry and research status. After that, the definition, users, features and community classification of video game live streaming are introduced in detail.
  • 8.1K
  • 02 Nov 2020
Topic Review
Matthews Correlation Coefficient
The Matthews correlation coefficient (MCC) or phi coefficient is used in machine learning as a measure of the quality of binary (two-class) classifications, introduced by biochemist Brian W. Matthews in 1975. The MCC is defined identically to Pearson's phi coefficient, introduced by Karl Pearson, also known as the Yule phi coefficient from its introduction by Udny Yule in 1912. Despite these antecedents which predate Matthews's use by several decades, the term MCC is widely used in the field of bioinformatics and machine learning. The coefficient takes into account true and false positives and negatives and is generally regarded as a balanced measure which can be used even if the classes are of very different sizes. The MCC is in essence a correlation coefficient between the observed and predicted binary classifications; it returns a value between −1 and +1. A coefficient of +1 represents a perfect prediction, 0 no better than random prediction and −1 indicates total disagreement between prediction and observation. However, if MCC equals neither −1, 0, or +1, it is not a reliable indicator of how similar a predictor is to random guessing because MCC is dependent on the dataset. MCC is closely related to the chi-square statistic for a 2×2 contingency table where n is the total number of observations. While there is no perfect way of describing the confusion matrix of true and false positives and negatives by a single number, the Matthews correlation coefficient is generally regarded as being one of the best such measures. Other measures, such as the proportion of correct predictions (also termed accuracy), are not useful when the two classes are of very different sizes. For example, assigning every object to the larger set achieves a high proportion of correct predictions, but is not generally a useful classification. The MCC can be calculated directly from the confusion matrix using the formula: In this equation, TP is the number of true positives, TN the number of true negatives, FP the number of false positives and FN the number of false negatives. If any of the four sums in the denominator is zero, the denominator can be arbitrarily set to one; this results in a Matthews correlation coefficient of zero, which can be shown to be the correct limiting value. The MCC can be calculated with the formula: using the positive predictive value, the true positive rate, the true negative rate, the negative predictive value, the false discovery rate, the false negative rate, the false positive rate, and the false omission rate. The original formula as given by Matthews was: This is equal to the formula given above. As a correlation coefficient, the Matthews correlation coefficient is the geometric mean of the regression coefficients of the problem and its dual. The component regression coefficients of the Matthews correlation coefficient are Markedness (Δp) and Youden's J statistic (Informedness or Δp'). Markedness and Informedness correspond to different directions of information flow and generalize Youden's J statistic, the [math]\displaystyle{ \delta }[/math]p statistics and (as their geometric mean) the Matthews Correlation Coefficient to more than two classes. Some scientists claim the Matthews correlation coefficient to be the most informative single score to establish the quality of a binary classifier prediction in a confusion matrix context.
  • 8.1K
  • 18 Nov 2022
Topic Review
Self-confidence
The concept of self-confidence is commonly used as self-assurance in one's personal judgment, ability, power, etc. One's self confidence increases from experiences of having satisfactorily completed particular activities. It is a positive belief that in the future one can generally accomplish what one wishes to do. Self-confidence is not the same as self-esteem, which is an evaluation of one's own worth, whereas self-confidence is more specifically trust in one's ability to achieve some goal, which one meta-analysis suggested is similar to generalization of self-efficacy. Abraham Maslow and many others after him have emphasized the need to distinguish between self-confidence as a generalized personality characteristic, and self-confidence with respect to a specific task, ability or challenge (i.e. self-efficacy). Self-confidence typically refers to general self-confidence. This is different from self-efficacy, which psychologist Albert Bandura has defined as a “belief in one’s ability to succeed in specific situations or accomplish a task” and therefore is the term that more accurately refers to specific self-confidence. Psychologists have long noted that a person can possess self-confidence that he or she can complete a specific task (self-efficacy) (e.g. cook a good meal or write a good novel) even though they may lack general self-confidence, or conversely be self-confident though they lack the self-efficacy to achieve a particular task (e.g. write a novel). These two types of self-confidence are, however, correlated with each other, and for this reason can be easily conflated.
  • 8.1K
  • 18 Oct 2022
Biography
John F. MacArthur
John Fullerton MacArthur Jr. (born June 19, 1939) is an American Protestant pastor and author known for his internationally syndicated Christian teaching radio and television program Grace to You.[1] He has been the pastor of Grace Community Church, a non-denominational church in Sun Valley, California, since February 9, 1969.[2] He is currently Chancellor Emeritus of The Master's University in
  • 8.1K
  • 15 Nov 2022
Topic Review
Application of RAP in Asphalt Concrete Pavements
The use of recycled asphalt pavement (RAP) materials in asphalt concrete pavements (ACP) brings significant cost and environmental benefits. In practice, however, the amount of RAP readily available far exceeds the amount being utilized in ACPs, which still leaves the problem of excess RAP in the environment partially solved. Additionally, ACPs containing RAP materials (i.e., RAP-ACPs) can still be landfilled after they have reached the end of their useful life, which may restore the original environmental waste problem. To address these, researchers have demonstrated different ways to maximize the application of RAP in ACPs. Among them, the use of RAP in pavement preventive maintenance (PPM) treatments and the repeated recycling of RAP-ACPs (i.e., RnAP) are specifically discussed herein. It is envisaged that, by promoting these two practices, the application and benefits of RAP can be further maximized to improve sustainability. 
  • 8.1K
  • 25 Nov 2022
Biography
Victor Hugo
Victor Marie Hugo French: [viktɔʁ maʁi yɡo] 26 February 1802 – 22 May 1885) was a French poet, novelist, and dramatist of the Romantic movement. Hugo is considered to be one of the greatest and best-known French writers. Outside of France, his most famous works are the novels Les Misérables, 1862, and The Hunchback of Notre-Dame (French: Notre-Dame de Paris), 1831. In France, Hugo is kno
  • 8.1K
  • 30 Nov 2022
Biography
Shahid Khan
Shahid Khan (Urdu: شاہد خان‎; born July 18, 1950),[1][2] also known as Shad Khan, is a Pakistani-American billionaire businessman and philanthropist. He is the owner of the Jacksonville Jaguars of the National Football League (NFL) and Fulham F.C. of the English Premier League. Khan is also the owner of the automobile parts manufacturer Flex-N-Gate in Urbana, Illinois. Khan was feature
  • 8.1K
  • 30 Nov 2022
Topic Review
Ancient Egyptian Medicine
The medicine of the ancient Egyptians is some of the oldest documented. From the beginnings of the civilization in the late fourth millennium BC until the Persian invasion of 525 BC, Egyptian medical practice went largely unchanged and included simple non-invasive surgery, setting of bones, dentistry, and an extensive set of pharmacopoeia. Egyptian medical thought influenced later traditions, including the Greeks.
  • 8.1K
  • 20 Oct 2022
Topic Review
Ethology
Ethology is the scientific study of animal behaviour, usually with a focus on behaviour under natural conditions, and viewing behaviour as an evolutionarily adaptive trait. Behaviourism as a term also describes the scientific and objective study of animal behaviour, usually referring to measured responses to stimuli or to trained behavioural responses in a laboratory context, without a particular emphasis on evolutionary adaptivity. Throughout history, different naturalists have studied aspects of animal behaviour. Ethology has its scientific roots in the work of Charles Darwin and of American and German ornithologists of the late 19th and early 20th century, including Charles O. Whitman, Oskar Heinroth, and Wallace Craig. The modern discipline of ethology is generally considered to have begun during the 1930s with the work of Dutch biologist Nikolaas Tinbergen and Austrian biologists Konrad Lorenz and Karl von Frisch, the three recipients of the 1973 Nobel Prize in Physiology or Medicine. Ethology combines laboratory and field science, with a strong relation to some other disciplines such as neuroanatomy, ecology, and evolutionary biology. Ethologists typically show interest in a behavioural process rather than in a particular animal group, and often study one type of behaviour, such as aggression, in a number of unrelated species. Ethology is a rapidly growing field. Since the dawn of the 21st century researchers have re-examined and reached new conclusions in many aspects of animal communication, emotions, culture, learning and sexuality that the scientific community long thought it understood. New fields, such as neuroethology, have developed. Understanding ethology or animal behaviour can be important in animal training. Considering the natural behaviours of different species or breeds enables trainers to select the individuals best suited to perform the required task. It also enables trainers to encourage the performance of naturally occurring behaviours and the discontinuance of undesirable behaviours.
  • 8.1K
  • 09 Nov 2022
Topic Review
Adaptive Reuse of Architectural Heritage
       Significant architectural and historical monuments become an important point of reference for the local population, increasing their sense of security, and act as a factor shaping social identity. An effort to preserve relevant objects in a city is therefore important both for retaining its unique features and for strengthening the local community. A significant role plays here the adaptive reuse of architectural heritage, which allows for the preservation of architectural objects that are important to the local community, promoting the integrity and historical continuity of the city while restoring the objects’ functional and economic value.         The introduction of a new function in architectural heritage is not only an important impulse for the tangible regeneration of urban tissue, but can also help to reconstruct the image and identity of a city. The local cultural and architectural heritage plays a significant role in the process leading to the creation of positive references and elimination of negative connotations related to an economic or social crisis. These remain an important part of the history of a city and, at the same time, its significance may be reimagined and shown in a new context, that relates to the present day. As a result, artefacts of the past gain new meanings, which are subject to a different, contemporary interpretation through the prism of current needs and ideas. Objects or even groups of objects from the past are being consciously taken into consideration in the activities currently undertaken. The contemporary scale of the phenomenon and complexity of the issues concerning the adaptive reuse of architectural heritage are a consequence of the multi-faceted transformations that have taken place in recent decades in the social, cultural and economic spheres, and, consequently, the contemporary understanding of the role and significance of the architectural heritage.
  • 8.0K
  • 31 Aug 2021
Topic Review
List of Temples in Tamil Nadu
This is a list of temples in the Indian state of Tamil Nadu which is famed for Hindu temples, culture and tradition and commonly known as the Land of Temples. Tamil Nadu has more temples than any other states of India. Tamil Nadu is home to more than 40,000 Hindu, Buddhist, Jain, local deities, Ayyavazhi temples and is aptly called "the land of temples" by media. Many are at least 800 to 5000 years old and are found scattered all over the state. The rulers of various dynasties constructed these temples over centuries. Vimanas (storeys) and Gopuram (towering gateways to the temple complex) best characterize the temples of Tamil Nadu. As per Tamil Nadu Hindu Endowments Board, there are 38,615 temples. Most of the largest Hindu temples reside here. Studded with complex architecture, variety of sculptures, and rich inscriptions, the temples remain the very essence of the culture and heritage of Tamil land, with historical records dating back to at least 3,000 years. In Madurai, Meenakshi Amman Temple has high ‘Gopuram’ towers ornamented with colourful figures. On Pamban Island, Ramanathaswamy Temple is a famous pilgrimage site. The town of Kanyakumari, at India's southernmost tip, is the site of ritual sunrises. The state also abounds with temple tanks. The state has 2,359 temple tanks located in 1,586 temples. The government has identified 1,068 tanks for renovation. People from all over the world visits Temples of Tamil Nadu and it is the major Tourist attraction in India.
  • 8.0K
  • 07 Nov 2022
Topic Review
Two-Dimensional Space
Two-dimensional space (also known as 2D space, 2-space, or bi-dimensional space) is a geometric setting in which two values (called parameters) are required to determine the position of an element (i.e., point). The set [math]\displaystyle{ \mathbb{R}^2 }[/math] of pairs of real numbers with appropriate structure often serves as the canonical example of a two-dimensional Euclidean space. For a generalization of the concept, see dimension. Two-dimensional space can be seen as a projection of the physical universe onto a plane. Usually, it is thought of as a Euclidean space and the two dimensions are called length and width.
  • 8.0K
  • 28 Nov 2022
Topic Review
Meat Packaging
The term ‘packaging’ refers to the technological intervention aimed at the protection of food from a variety of factors, which provokes the product detriment. Packaging is considered as one of the most interesting technological aspects and a constantly evolving issue in food production. 
  • 8.0K
  • 21 Jan 2021
Topic Review
VDM-1
The Processor Technology VDM-1, for Video Display Module, was the first video card for S-100 bus computers. Created in 1975, it allows an S-100 machine to produce its own display, and when paired with a keyboard and their 3P+S card, it eliminates the need for a separate video terminal. Using a 7 x 9 dot matrix and ASCII characters, it produces a 64-column by 16-row text display. The VDM-1 is a complex card and was soon replaced by an increasing number of similar products from other companies. An early competitor was the Solid State Music VB-1, which offers an identical display from a much simpler card. Later cards using LSI chips have enough room to include the keyboard controller as well.
  • 8.0K
  • 08 Oct 2022
Biography
Bill Maher
William Maher (/mɑːr/; born January 20, 1956)[1] is an American comedian, political commentator, and television host. He is known for the HBO political talk show Real Time with Bill Maher (2003–present) and the similar late-night show called Politically Incorrect (1993–2002), originally on Comedy Central and later on ABC. Maher is known for his political satire[2] and sociopolitical comme
  • 8.0K
  • 29 Nov 2022
Topic Review
Charging Technology for Battery Electric Buses
The charging infrastructure has a key role in the implementation of battery electric buses (BEBs) in cities. BEBs only use off-board chargers, whereas the PEC to convert the three-phase AC power from the grid into DC power to charge the battery is located outside the BEB. These chargers allow higher charging power levels because they are not restricted in size and weight. Furthermore, since the driving range of a BEB is limited, a specific charging concept and interface is required to keep the BEB running during the day. This entry gives an overview of the existing charging interfaces and concepts and charger and PEC topologies to provide a reliable and efficient charging behavior.
  • 8.0K
  • 18 Nov 2021
Topic Review
Tumoroid
The term “tumoroid” means “tumor-like organoid”: tumoroids typically derive from primary tumors harvested from oncological patients and they can mimic human tumor microenvironment (TME); nowadays, they are considered a promising tool for cost-effective studies on novel anticancer drugs to be used in precision medicine in the field of oncology.
  • 8.0K
  • 18 Jun 2024
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