Naval History and Heritage Command

Abstract: In 1998, tropical sea surface temperatures were the highest on record, topping off a 50‐year trend for some tropical oceans. In the same year, coral reefs around the world suffered the most extensive and severe bleaching ( loss of symbiotic algae) and subsequent mortality on record. These events may not be attributable to local stressors or natural variability alone but were likely induced by an underlying global phenomenon. It is probable that anthropogenic global warming has contributed to the extensive coral bleaching that has occurred simultaneously throughout the reef regions of the world. The geographic extent, increasing frequency, and regional severity of mass bleaching events are an apparent result of a steadily rising baseline of marine temperatures, combined with regionally specific El Niño and La Niña events. The repercussions of the 1998 mass bleaching and mortality events will be far‐reaching. Human populations dependent on reef services face losses of marine biodiversity, fisheries, and shoreline protection. Coral bleaching events may become more frequent and severe as the climate continues to warm, exposing coral reefs to an increasingly hostile environment. This global threat to corals compounds the effects of more localized anthropogenic factors that already place reefs at risk. Significant attention needs to be given to the monitoring of coral reef ecosystems, research on the projected and realized effects of global climate change, and measures to curtail greenhouse gas emissions. Even those reefs with well‐enforced legal protection as marine sanctuaries, or those managed for sustainable use, are threatened by global climate change.

The objective of this project is to create a new implementation of a deep learning model that uses digital elevation data to detect shipwrecks automatically and rapidly over a large geographic area. This work is intended to apply a new methodology to the field of underwater archaeology. Shipwrecks represent a major resource to understand maritime human activity over millennia, but underwater archaeology is expensive, misappropriated, and hazardous. An automated tool to rapidly detect and map shipwrecks can therefore be used to create more accurate maps of natural and archaeological features to aid management objectives, study patterns across the landscape, and find new features. Additionally, more comprehensive and accurate shipwreck maps can help to prioritize site selection and plan excavation. The model is based on open source topo-bathymetric data and shipwreck data for the United States available from NOAA. The model uses transfer learning to compensate for a relatively small sample size and addresses a recurring problem that associated work has had with false positives by training the model both on shipwrecks and background topography. Results of statistical analyses conducted—ANOVAs and box and whisker plots—indicate that there are substantial differences between the morphologic characteristics that define shipwrecks vs. background topography, supporting this approach to addressing false positives. The model uses a YOLOv3 architecture and produced an F1 score of 0.92 and a precision score of 0.90, indicating that the approach taken herein to address false positives was successful.

Summary. Textiles from the North Caucasus Majkop culture (3700–3200 cal BC) site of Novosvobodnaya were selected for a programme of examination. Wool, flax and cotton‐like plant‐fibre threads were identified. This is the oldest example of wool so far identified in the archaeological record. Weaving techniques employed in making the textiles included the use of tablets or discs, and a simple frame. In addition, two dyeing techniques using tannin dyes have been determined.

This article compares the traditional, fixed problem representation style of a genetic algorithm (GA) with a new floating representation in which the building blocks of a problem are not fixed at specific locations on the individuals of the population. In addition, the effects of noncoding segments on both of these representations is studied. Noncoding segments are a computational model of noncoding deoxyribonucleic acid, and floating building blocks mimic the location independence of genes. The fact that these structures are prevalent in natural genetic systems suggests that they may provide some advantages to the evolutionary process. Our results show that there is a significant difference in how GAs solve a problem in the fixed and floating representations. Genetic algorithms are able to maintain a more diverse population with the floating representation. The combination of noncoding segments and floating building blocks appears to encourage a GA to take advantage of its parallel search and recombination abilities.

We suggest epoxycyclopentane (ECP) as a novel guest compound for hydrate-based energy storage. All of the key properties of the ECP hydrate, including the thermodynamic stability, storage capacity, and formation condition, are notably superior to those of hydrates containing tetrahydrofuran (THF) and cyclopentane (CP), currently considered to be the most powerful promoters.

Abstract (1.) Plane Water-Lines in two Dimensions defined.—By the term “Plane Water-Line in two Dimensions” is meant a curve which a particle of liquid describes in flowing past a solid body, when such flow takes place in plane layers of uniform thickness. Such curves are suitable in practice for the water-lines of a ship, in those cases in which the vertical displacements of the particles of water are small compared with the dimensions of the ship; for in such cases the assumption that the flow takes place in plane layers of uniform thickness, though not absolutely true, is sufficiently near the truth for practical purposes, so far as the determination of good forms of water-line is concerned. As water-line curves have at present no single word to designate them in mathematical language, it is proposed, as a convenient and significant term, to call them Neoïds (from νηòς, the Ionic genitive of νηòς). (2.) General Principles of the Flow of a Liquid past a Solid.—The most complete exposition yet published, so far as I know, of the principles of the flow of a liquid past a solid, is contained in Professor Stokes’s paper “On the Steady Motion of an Incompressible Fluid,” published in the Transactions of the Cambridge Philosophical Society for 1842. So far as those principles will be referred to in the present paper, they may be summed up as follows.

Journal Article Securing Command of the Sea: NATO Naval Planning, 1948–1954. By Sean M. Maloney. (Annapolis: Naval Institute Press, 1995. xiv, 276 pp. $38.95, ISBN 1-55750-562-4.) Get access Jeffrey G. Barlow Jeffrey G. Barlow Naval Historical Center, Washington, D.C. Search for other works by this author on: Oxford Academic Google Scholar Journal of American History, Volume 83, Issue 1, June 1996, Page 282, https://doi.org/10.2307/2945608 Published: 01 June 1996

Black Yanks in the Pacific tells the story of black soldiers stationed in Asia during the first seven years of the Cold War. More than six thousand black soldiers served in Japan during the occupation, primarily in segregated units. Michael Cullen Green contends that black soldiers thrived there, enjoying social services and material comforts rarely available to them back home. Rather than showing solidarity with the Japanese as similar racially oppressed victims, they embraced the American occupational policies and reveled in their newfound status as occupiers, taking full advantage of their superior social and economic position in a vanquished land. Nearly one-third of the book is devoted to analyzing relations between black soldiers and Japanese women—intimate affairs that led to very few marriages but a plethora of mixed-race offspring who would be abandoned in Japan to confront a lifetime of racial prejudice. During the Korean War, the author argues, the trend of black soldiers identifying with the American cause and eschewing “a race-based interpretation of U.S. policy” continued despite the bitter experience of the Twenty-Fourth Infantry Regiment, which suffered terrible losses early in the war due to deficiencies in training, equipment, and leadership (p. 133). Because of the economic benefits and job security offered by the military, many black soldiers opted to stay in the army after the Korean War and later went on to fight in Vietnam. The experience of service in the Pacific convinced many black soldiers not only to make the military a career but also to reassess their identity as African Americans.

Abstract Tropical cyclone (TC) activities over the western North Pacific (WNP) and TC landfall in Japan are investigated by collecting historical TC track data and meteorological observation data starting from the mid-nineteenth century. Historical TC track data and TC best track data are merged over the WNP from 1884 to 2018. The quality of historical TC data is not sufficient to count the TC numbers over the WNP due to the lack of spatial coverage and different TC criteria before the 1950s. We focus on TC landfall in Japan using a combination of TC track data and meteorological data observed at weather stations and lighthouses from 1877 to 2019. A unified TC definition is applied to obtain equivalent quality during the whole analysis period. We identify lower annual TC landfall numbers during the 1970s to the 2000s and find other periods have more TC landfall numbers including the nineteenth century. No trend in TC landfall number is detected. TC intensity is estimated by an annual power dissipation index (APDI). High APDI periods are found to be around 1900, in the 1910s, from the 1930s to 1960s, and after the 1990s. When we focus on the period from 1977 to 2019, a significant increasing trend of ADPI is seen, and significant northeastward shift of TC landfall location is detected. On the other hand, TC landfall location shifts northeastward and then southwestward in about 100-year interval. European and US ships sailed through East and Southeast Asian waters before the weather station network was established in the late nineteenth century. Then, we focus on TC events in July 1853 observed by the US Naval Japan Expedition of Perry’s fleet and August 1863 by a UK Navy ship that participated in two wars in Japan. A TC moved slowly westward over the East China Sea south of the Okinawa Islands from 21 to 25 July 1853. Another TC was detected in the East China Sea on 15–16 August 1863 during the bombardment of Kagoshima in southern Japan. Pressure data are evaluated by comparing the observations made by 10 naval ships in Yokohama, central Japan during 1863–1864. The deviation of each ship pressure data from the 10 ships mean is about 2.7–2.8 hPa.

Essay| May 01 1933 Mexican Constitutional Changes Charles W. Hackett Charles W. Hackett Professor of Latin-American History, University of Texas; Current History Associate Search for other works by this author on: This Site PubMed Google Scholar Current History (1933) 38 (2): 212–214. https://doi.org/10.1525/curh.1933.38.2.212 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Twitter LinkedIn Tools Icon Tools Get Permissions Cite Icon Cite Search Site Citation Charles W. Hackett; Mexican Constitutional Changes. Current History 1 May 1933; 38 (2): 212–214. doi: https://doi.org/10.1525/curh.1933.38.2.212 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentCurrent History Search This content is only available via PDF. © 1933 by The Regents of the University of California1933 Article PDF first page preview Close Modal You do not currently have access to this content.

Essay| December 01 1926 Cathode Ray a New Tool of Science Watson Davis Watson Davis Science Editor, Current History Search for other works by this author on: This Site PubMed Google Scholar Current History (1926) 25 (3): 392–396. https://doi.org/10.1525/curh.1926.25.3.392 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Twitter LinkedIn Tools Icon Tools Get Permissions Cite Icon Cite Search Site Citation Watson Davis; Cathode Ray a New Tool of Science. Current History 1 December 1926; 25 (3): 392–396. doi: https://doi.org/10.1525/curh.1926.25.3.392 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentCurrent History Search This content is only available via PDF. © 1926 by The Regents of the University of California1926 Article PDF first page preview Close Modal You do not currently have access to this content.

Essay| May 01 1991 Mozambique’s Search for Stability Virginia Curtin Knight Virginia Curtin Knight Consulting Editor, Current History Virginia Curtin Knight, a consulting editor of Current History, is a freelance writer who currently lives and works in Zimbabwe. Search for other works by this author on: This Site PubMed Google Scholar Current History (1991) 90 (556): 217–220. https://doi.org/10.1525/curh.1991.90.556.217 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Twitter LinkedIn Tools Icon Tools Get Permissions Cite Icon Cite Search Site Citation Virginia Curtin Knight; Mozambique’s Search for Stability. Current History 1 May 1991; 90 (556): 217–220. doi: https://doi.org/10.1525/curh.1991.90.556.217 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentCurrent History Search This content is only available via PDF. © 1991 by The Regents of the University of California1991 Article PDF first page preview Close Modal You do not currently have access to this content.

Headmen, chiefs, kings, and emperors, the titled leaders of numerous traditional cultures in the Pacific Islands, sub-Saharan Africa and lowland South America, wear necklaces of large canines from the most powerful and ferocious animals in their respective environments. These formal badges of office symbolize their power, leadership, rank and authority in society. This generalized theme is predicated on the thesis that a leader's power is equivalent to that of the animal from which the teeth were extracted; that is, cultural man has borrowed a model from nature on which to base his power. The fact that humankind uses this same conceptual model in numerous places around the world indicates that the human mind functions in much the same way everywhere. Regarding the method used in this work, in each example presented, the presence of a visual image is considered fundamental to the overall process of gathering documentary evidence in support of this thesis. In each instance too, published data are used to confirm the title, culture, place, and, where possible, the name of the individual wearning the tooth necklace, and the circumstances under which it was worn. © 1997 John Wiley & Sons, Ltd.

(1991). ‘Only by the sword’: British counter‐insurgency in Iraq, 1920. Small Wars & Insurgencies: Vol. 2, No. 2, pp. 323-363.

Two questions relating to copyright in unpublished records are considered: archivists' obligations and privileges under United States copyright law, and archivists' responsibilities beyond merely legal ones. The 1976 Copyright Act clarified archivists' obligations by terminating perpetual copyright and by granting archives authority to reproduce copyrighted works under certain conditions. The ambiguous applicability of this authority and of "fair use" to unpublished records continues to complicate archivists' work. Archivists serve scholarship by accepting transfer of copyright in acquired records, by including information on copyright status in inventories, and by understanding copyright well enough to explain it to both researchers and copyright owners.

Abstract Electronic band structure (BS) and crystal structure are the two complementary identifiers of solid state materials. While convenient instruments and reconstruction algorithms have made large, empirical, crystal structure databases possible, extracting quasiparticle dispersion (closely related to BS) from photoemission band mapping data is currently limited by the available computational methods. To cope with the growing size and scale of photoemission data, we develop a pipeline including probabilistic machine learning and the associated data processing, optimization and evaluation methods for band structure reconstruction, leveraging theoretical calculations. The pipeline reconstructs all 14 valence bands of a semiconductor and shows excellent performance on benchmarks and other materials datasets. The reconstruction uncovers previously inaccessible momentum-space structural information on both global and local scales, while realizing a path towards integration with materials science databases. Our approach illustrates the potential of combining machine learning and domain knowledge for scalable feature extraction in multidimensional data.

In this paper, we design and fabricate a novel broadband tunable absorber based on a PIN diode-loaded frequency selective surface (FSS). The absorber is a four- layer structure, and from the top to the bottom are the active FSS (AFSS) layer, the dielectric substrate, the air layer and the metal ground. The AFSS layer is designed as a symmetrical strip with a PIN diode loaded in the middle, which have an adjustable resistance to obtain a tunable and broadband absorption capability. At the same time, a simple bias network is designed to supply an appropriate diode control voltage. The simulations show that the reflectivity can be adjusted below −10dB from 2.3 to 14.5 GHz and the rasorber achieved a broadband absorption. The measurement shows that the frequency range of the rasorber reflectivity less than −10dB is 2.35 to 13.44GHz by adjusting the voltage applied on the PIN diodes. The good agreement between simulations and measurements verifies our design. What's more, the absorber has an overall thickness of 7.524 mm, which is about only 0.059λ of the lowest working frequency and is superior to the conventional passive absorbers. In general, this broadband tunable absorber has great application value in wireless communication, antenna, stealth and radar detection, especially for C-band and X- band radar detection and stealth.

Journal Article Operation Drumbeat: The Dramatic True Story of Germany's First U-Boat Attacks Along the American Coast in World War II. By Michael Gannon. (New York: Harper & Row, 1990. xxii + 490 pp. $24.95.) Get access Gary E. Weir Gary E. Weir Naval Historical Center Search for other works by this author on: Oxford Academic Google Scholar Journal of American History, Volume 78, Issue 2, September 1991, Pages 731–732, https://doi.org/10.2307/2079664 Published: 01 September 1991

Since the Great War of 1914-1918 the relationship between naval officers and ocean scientists in the United States has illustrated well the unpredictable effect of cultural barriers on constructive professional dialogues. The customs and practices attending an academic or industrial laboratory differ dramatically from those absorbed by midshipmen at the United States Naval Academy or officers on board combat ships. Each group lives in a nearly discreet, culturally constructed world. During the course of this century the communication and understanding necessary for these communities to work together toward a common goal required social and political insight as well as extensive entrepreneurship and careful cultural translation. Confronting a poverty of resources after World War One the Navy and the civilian oceanographic community formed a common practice to pool both resources and skill in an effort to perform meaningful ocean research. When the possibility of another war loomed large in the 1930s, they turned to determined cultural translators. The latter, drawn from both communities, converted the primitive common practice and considerable cultural obstacles of the interwar period into a fluid wartime professional dialogue. Fortified by success in World War II, key translators brought the dialogue to maturity after 1945.

(2002). British command and control in the Falklands Campaign. Defense & Security Analysis: Vol. 18, No. 4, pp. 333-349.