Thousands Of Panels Research Articles

Real-time inspection and fault detection for large photovoltaic arrays based on drones and deep learning algorithms

In recent years, the installation of renewable energy generation systems based on photovoltaic (PV) panels has experienced massive increments and PV parks with thousands of panels are now becoming commonplace. Yet, there are some challenges, like inspection and fault detection. Lately, these operations have been approached using drones. This project adds the use of deep learning, more specifically proposes the convolutional neural network (CNN) algorithm, the YOLOv5 model and Real-Time Messaging Protocol (RTMP) protocol to achieve real-time detection of PV panels failures. The YOLOv5 model was trained by sets sorted into 9 different categories including fault and abnormal objects’ coverage. This multi-class classification system was investigated by a variety of evaluation indexes to show effectiveness and accuracy. The system was also examined with its different fault classes. The performance results demonstrate that the mean average precision could reach up to 98% with a good training set, confirming the feasibility of proposed approaches.

An Integrated Structure Analysis Method of Active Surface Antenna by Using the Simplified Actuator

The main surface of a large reflector antenna is composed of thousands of panels, which are inevitably deformed under natural load, leading to a great deterioration of electrical performance of the antenna. The active surface technique is an effective method to compensate antenna deformation error and has been widely used. The actuator is a complex component, it has not been established in the antenna structure analysis model, which limits the theoretical analysis ability of the active surface technology. To solve this problem, an integrated structure analysis method of active surface antenna by using the simplified actuator is proposed. First, according to the supporting characteristics and adjusting function of the actuator, the complex actuator is simplified a simple structure of support beams, support truss and adjustment beam. Second, the finite element model of the active surface antenna including the simplified actuator is established. Then, the relationship between the adjustment value (load) of adjustment beam and the deformation of the antenna structure is deduced, and the integrated analysis method for realizing the active adjustment of panels is established. Finally, the model and adjustment analysis method of the active surface antenna in this paper is applied to an 8 m antenna, and satisfactory structural analysis results are obtained, which shows the effectiveness and universality of the method, and provides a reference for the modeling and adjustment analysis of the active surface antenna.

Electronic Performance-Oriented Mold Sharing Method and Application in QTT 110 m Large Radio Telescope

The reflector surface of a large reflector antenna may even consist of thousands of panels, and if the panel molds with high-precision requirements are fabricated uniquely for each ring, the overall cost will be very high. Therefore, from a perspective of reducing the cost, the mold sharing design is of particular significance. In order to obtain the minimum number of molds satisfying the given electronic performance index, the electronic performance-oriented mold sharing design is suggested, in which the effective surface accuracy is used to evaluate electrical performance. The smaller the combined effective root-mean-square (rms) error value introduced after sharing the mold, the more preferential these rings should share the mold to reduce the number of molds. Based on such idea, a fast mold reduction process is presented, which can give the minimum number of molds quickly according to the electrical performance requirements. During this process, a combined effective rms value matrix and a mold sharing discriminant matrix are defined and used. To construct these two matrices, the panel normal error induced by mold sharing is derived, and the optimal mold position is determined first. As a test problem, application of the proposed method to mold reduction of a 110 m radio telescope is presented, and the discussions of the results are given.

Whose Freedom of Religion?

Whose Freedom of Religion? Peter Heinegg Religious Freedom: The Contested History of an American Idea. By Tisa Wenger, Chapel Hill, NC: University of North Carolina Press, 2017. 298 pp. $34.95. In this intellectually original, carefully conceived, cogently argued, but dully written work, Wenger (who teaches American religious history at Yale) surveys the baffling variety of ways the sacrosanct principle of freedom of religion has been used as a tool or weapon in crucial episodes of our history where politics, culture, and race were at least as much the issue as religion. Starting in the late nineteenth century and working through the mid‐twentieth century, Wenger focuses on the role of religious freedom in the U.S. occupation of the Philippines, government interference in ritual practices on Indian reservations, the quest for social acceptance by Catholics and Jews, and the African‐American struggle for equality. To call the concept a double‐edged sword would be an understatement. The American seizure of the Philippines in the wake of the Spanish‐American War might have been (was) an act of naked aggression, but politicians, clergymen, and journalists liked to see it as a Christian liberation of Filipinos from the medieval yoke of Spanish Catholicism. (The same notion applied to Cuba and Puerto Rico.) Of course, given the “infantile” condition of the natives, any real self‐determination would have to be put on hold (until 1946, as it turned out). But turnabout is fair play; and fighters for Philippine independence could claim that, like their white Protestant liberators‐adversaries, they believed in both the unique greatness of Christianity and the separation of church and state. And even traditional Catholics loyal to Rome could stress their superiority to both the Moros (militant Muslims in the south of the country) and pagan peoples. Yet, as with most of the other oppressed groups Wenger has studied, whatever American‐style rights the Filipinos maintained they had were not enough to move their American conquerors. And by stressing religion (the only legal card they had) to the exclusion of other elements of their identity, Filipinos were both misrepresenting themselves and not confronting the massive racism behind U.S. imperialism (but how could they?). Even before this time, American Indians, decimated and robbed of practically everything, were making desperate attempts to hold on to what was left of their native traditions, which included such late developments as the Ghost Dances (whence the catastrophic Battle of Wounded Knee in 1890), the “Shakers” in the Pacific Northwest (unrelated to the New England followers of Mother Ann Lee), and the peyotists (later incorporated as the Native American Church) in the Southwest. But they faced fierce resistance from the committed racists running the all‐powerful Bureau of Indian Affairs; and their invoking of freedom of religion to defend their folkways largely went for naught. What little success they had—at least until FDR's wise appointment of John Collier as head of the B.I.A. in 1934—was won by shaping their ceremonies to resemble Christian worship (and underlying belief) as much as possible. And once again, presenting their cause as wholly religious involved a serious distortion. The classical Enlightenment distinction between the sacred and the profane simply didn't apply to the Indians, whose languages often had no word for “religion” and whose “services” formed part of an all‐encompassing way of life. The most successful saluting the flag of religious freedom took place among Catholics and Jews, though the Jews plainly faced much deeper and more bitter bias. But by the end of World War II, the “tri‐faith” of Protestant–Catholic–Jew had become more or less established as the normal spectrum of religion in America. To fit into this scheme, Jews had to downplay the role of “race” (history, language, and a vast array of customs and habits) in a manner that Zionists, among others, could never be comfortable with. But this adjustment basically worked, as the thousands of panels ever since that feature a team of minister‐priest‐and‐rabbi have demonstrated. (How long will it take before the presence of an imam is also de rigueur?) One downside to this equal status, Wenger insists, is that...

Writing a Chronicle History of China’s One-Child Policy: Three Books by Susan Greenhalgh

Writing a Chronicle History of China’s One-Child Policy:Three Books by Susan Greenhalgh Xiying Wang (bio) Susan Greenhalgh and Edwin Winckler. Governing China’s Population: From Leninist to Neoliberal Biopolitics. Stanford, CA: Stanford University Press, 2005. 412 pp. Hardcover $27.95, isbn 978-0-8047-4880-3. Susan Greenhalgh. Just One Child: Science and Policy in Deng’s China. Berkeley: University of California Press, 2008. xxii, 404 pp. $34.95, isbn 978-0-520-25339-1. Susan Greenhalgh. Cultivating Global Citizens: Population in the Rise of China. Cambridge, MA: Harvard University Press, 2010. 156 pp. Hardcover $32.50, isbn 978-0-674-05571-1. An Unexpected Experience In March 2013, I was attending the fifty-seventh Commission on the Status of Women, which was organized by the UN in New York and attended by over four thousand participants from around the world. Among thousands of panels, we Chinese delegates (including five to eight scholars, feminist activists, and women’s federation cadres) also organized a one-and-a-half-hour panel titled “Feminist Approaches to Address Gender-Based Violence in China,” mainly discussing the practices and strategies that Chinese feminists adopted to tackle this social problem after the 1995 Beijing conference, and the accomplishments achieved so far. Around thirty participants attended the panel, and all five presentations went well. However, the Q&A session turned into something beyond our imagination. Nobody asked any questions related to the issue of domestic violence. Instead, all the questions were addressed to the one-child policy—mainly challenging us, as Chinese feminists, “how can you tolerate such a coercive policy violating women’s bodies and rights?” A large poster sat on the conference room table with the bold title “Help Chinese Government to Stop Coercive One-Child Policy” with bloody pictures of girl killing and dead bodies as background. Under such [End Page 237] conditions, any explanation of the policy that we might have offered or endeavors to answer the questions would have been treated as defending the “coercive communist PRC regime,” and its absolute otherness from the Western world. One of our scholars and one questioner almost ended up arguing. This incident forced me to reflect on how to develop a feminist movement in the global world. Chinese feminists have to face historical and social issues like the one-child policy, the Cultural Revolution, and the 1989 students’ democracy movement, which have affected Chinese society deeply with trauma and violence. Confronting these inerasable dimensions of memory in China, rather than only focusing on more politically acceptable topics such as domestic violence, seems to some to be escapist. Moreover, how can Chinese feminists develop a unique standpoint with a feminist vision, viewpoint, and identity, and, at the same time, maintain a critical stance toward both China party-state discourse and Western ideology? To accomplish this end, the one-child policy is one of the biggest challenges that we face. Encountering Greenhalgh’s Books Fortunately, Greenhalgh’s three books are accessible and provide Chinese feminists (and others) with better knowledge and skills to tackle the issue of the one-child policy. She refutes the coercive story1 as the only way of understanding China’s population politics in the West by providing a more comprehensive and complicated chronicle history of governing China’s population since the establishment of the PRC. Greenhalgh’s twenty-five years of scholarship have mainly focused on answering one major question: “how China governs its population and to what effect” (2008, p. 41). This is “one of the most difficult” topics in the population field and a “hypersensitive” issue in the study of contemporary China (2010, p. 1). With ten years of experience in the leading international NGO Population Council as an anthropologist and China specialist (2008, p. 42), Greenhalgh was able to establish a reputation as a “friend of China” and “a constructive critic” within the high-profile inside circle of Chinese population experts and officials. She conducted 140 interviews with China’s population specialists and officials, and accessed extensive documents, articles, and books on the history of Chinese population science and policy, including many labeled as neibu (for internal use only) or even jimi (extremely secret). Her writing...

Hunting and Gender as Reflected in the Central Negev Rock Art, Israel

There are thousands of panels with hundreds of thousands of petroglyphs that occupy the rock outcropping of the Negev Highlands in southern Israel. These include abstract, zoomorphic and anthropomorphic elements, which are sometimes presented as hunting scenes. In this paper we will define hunting scene, review the themes and relate these figures to the economy, mundane, and spiritual realms of the artist. We argue that a clear panel grammar is in operation whereby the artist is creating a formulaic narrative that conveys a number of underlying messages that include the subsistence strategies and the success of the hunt. There is also subtle gender encoding that accompanies such imagery.

Paneling architectural freeform surfaces

The emergence of large-scale freeform shapes in architecture poses big challenges to the fabrication of such structures. A key problem is the approximation of the design surface by a union of patches, so-called panels, that can be manufactured with a selected technology at reasonable cost, while meeting the design intent and achieving the desired aesthetic quality of panel layout and surface smoothness. The production of curved panels is mostly based on molds. Since the cost of mold fabrication often dominates the panel cost, there is strong incentive to use the same mold for multiple panels. We cast the major practical requirements for architectural surface paneling, including mold reuse, into a global optimization framework that interleaves discrete and continuous optimization steps to minimize production cost while meeting user-specified quality constraints. The search space for optimization is mainly generated through controlled deviation from the design surface and tolerances on positional and normal continuity between neighboring panels. A novel 6-dimensional metric space allows us to quickly compute approximate inter-panel distances, which dramatically improves the performance of the optimization and enables the handling of complex arrangements with thousands of panels. The practical relevance of our system is demonstrated by paneling solutions for real, cutting-edge architectural freeform design projects.