Anthropocene Sea Level Change: A History of Recent Trends Observed in the U.S. East, Gulf, and West Coast Regions

Relative sea level (RSL) observations since 1969 at U.S. tide stations exhibit trends in RSL rise rate and acceleration that vary in response to both global and regional processes. Trend histories display a high degree of similarity between locations in coastal regions that are experiencing similar processes. With the exception of the U.S. Northeast Coast and Alaska,every other coastal location in the continental U.S. has experienced an upturn in RSL rise rate since 2013-2014 despite wide differences in the magnitude and trending direction of RSL acceleration. High RSL acceleration along the U.S. Northeast Coast has trended downward since 2011 while low RSL acceleration along the U.S Southeast Coast has recently trended upward in response to changes likely associated with ocean dynamics and ice sheet loss. RSL change in the sedimentary basins of the central U.S. Gulf Coast region is highly dependent on local rates of vertical land movement (VLM). VLM here varies over relatively short time scales amid changing patterns of subsurface water and hydrocarbons extraction.RSL rise rates of 5 mm/year or more aided by weak acceleration in Louisiana and Texas project a total RSL rise of between 0.4 and 0.5 meters above 1992 MSL by the year 2050; other Gulf and East Coast locations will experience equal or greater rise if upward trends in acceleration continue. Low and mostly downward trends in RSL rise rate at central U.S. West Coast locations have recently reverted to a pattern of upward trends with higher rise rates. Rise rates prior to 2013 appear to have been restrained by deceleration now trending toward acceleration. A combination of tectonic plate convergence and glacial isostatic adjustment makes the non-contiguous U.S. coastal state of Alaska unique with regard to RSL trends. Land emergence, rather than subsidence, produces consistent trends of falling RSL in Alaska

Very-high energy gamma-ray astronomy: A 23-year success story in high-energy astroparticle physics

Very-high energy (VHE) gamma quanta contribute only a minuscule fraction - below one per million - to the flux of cosmic rays. Nevertheless, being neutral particles they are currently the best "messengers" of processes from the relativistic/ultra-relativistic Universe because they can be extrapolated back to their origin. The window of VHE gamma rays was opened only in 1989 by the Whipple collaboration, reporting the observation of TeV gamma rays from the Crab nebula. After a slow start, this new field of research is now rapidly expanding with the discovery of more than 150 VHE gamma-ray emitting sources. Progress is intimately related with the steady improvement of detectors and rapidly increasing computing power. We give an overview of the early attempts before and around 1989 and the progress after the pioneering work of the Whipple collaboration. The main focus of this article is on the development of experimental techniques for Earth-bound gamma-ray detectors; consequently, more emphasis is given to those experiments that made an initial breakthrough rather than to the successors which often had and have a similar (sometimes even higher) scientific output as the pioneering experiments. The considered energy threshold is about 30 GeV. At lower energies, observations can presently only be performed with balloon or satellite-borne detectors. Irrespective of the stormy experimental progress, the success story could not have been called a success story without a broad scientific output. Therefore we conclude this article with a summary of the scientific rationales and main results achieved over the last two decades.Comment: 45 pages, 38 figures, review prepared for EPJ-H special issue "Cosmic rays, gamma rays and neutrinos: A survey of 100 years of research

On Small Satellites for Oceanography: A Survey

The recent explosive growth of small satellite operations driven primarily from an academic or pedagogical need, has demonstrated the viability of commercial-off-the-shelf technologies in space. They have also leveraged and shown the need for development of compatible sensors primarily aimed for Earth observation tasks including monitoring terrestrial domains, communications and engineering tests. However, one domain that these platforms have not yet made substantial inroads into, is in the ocean sciences. Remote sensing has long been within the repertoire of tools for oceanographers to study dynamic large scale physical phenomena, such as gyres and fronts, bio-geochemical process transport, primary productivity and process studies in the coastal ocean. We argue that the time has come for micro and nano satellites (with mass smaller than 100 kg and 2 to 3 year development times) designed, built, tested and flown by academic departments, for coordinated observations with robotic assets in situ. We do so primarily by surveying SmallSat missions oriented towards ocean observations in the recent past, and in doing so, we update the current knowledge about what is feasible in the rapidly evolving field of platforms and sensors for this domain. We conclude by proposing a set of candidate ocean observing missions with an emphasis on radar-based observations, with a focus on Synthetic Aperture Radar.Comment: 63 pages, 4 figures, 8 table

Značilnosti kanalskega in razpoklinskega toka izvira Pinarbaşi, Centralni Taurus, Seydişehir, Turčija

This study was conducted to investigate the flow and storage mechanisms of a karst aquifer located at the central Taurus Mountains, Turkey. As the biggest discharge point of the aquifer system, the flow characteristics are investigated at Pinarbaşi spring by using recession and time-series analyses. Continuous water level measurements are taken from the spring and are converted to flow rate by using a rating curve. The spring flows for 7 months (December 2014 – July 2015) and dries up for the rest of the year. Six individual recession periods are investigated and analyzed in the discharge time series. The recession coefficients (between 0.029 day-1 and 0.695 day-1) show that the flow within the aquifer system is mainly controlled by large open conduit and partly fracture porosity. The peak discharge is measured as 7.08 m3/s, and the maximum storage within the aquifer is calculated as 3.15 million m3. The continuous discharge data of the spring were evaluated combined with daily rainfall, temperature, electrical conductivity, and amount of suspended sediment in the water. Also a dye-tracing test was also applied to obtain the recharge-discharge relationship and porosity type of the aquifer system. Statistical tests on discharge hydrograph and tracer test showed that the memory of the karst aquifer was found to be about 3 days in the DJF period and about 15 days in the MAM period. The average elevation of the recharge area of the spring was determined to be 1,490 m by using stable isotope data of snow samples and was validated by dye tracer test made via the swallow hole in the recharge area. The total discharge for the year 2015 is estimated at 16.2 million m3 that approximately 25% of the total discharge is caused by snowmelt.Raziskovali smo dinamiko toka in skladiščenja v kraškem vodonosnika v Centralnem Taurusu v Turčiji. Z recesijsko analizo in analizo časovnih vrst pretoka smo raziskovali značilnosti največjega izvira vodonosnika, izvira Pinarbaşi. Časovno vrsto pretoka smo izračunali iz podatkov zveznih meritev nivoja in pretočne krivulje. Izvir je bil aktiven med decembrom 2014 in julijem 2015, preostali del leta je bil suh. Analizirali šest recesijskih obdobij. Koeficienti recesije, ki so med 0.029 dan-1 in 0,695 dan-1, kažejo na kanalsko in razpoklinsko poroznost. Največji izmerjeni pretok je bil 7,08 m3/s, največji izračunani volumen uskladiščene vode pa 3,15 milijona m3. Z analizo časovnih vrst smo raziskovali korelacijo med pretokom ter padavinami, temperaturo, električno prevodnostjo in motnostjo. Polnjenje in praznjenje ter strukturo vodonosnika smo določali tudi z sledilnim poskusom. Statistična analiza in rezultati sledenja so pokazali, da je spominski čas vodonosnika 3 dni v obdobju od decembra do februarja in 15 dni v obdobju od marca do maja. Z analizo stabilnih izotopov v vzorcih snega smo ugotovili, da je povprečna nadmorska višina prispevnega območja 1490 m. To potrjuje tudi sledilni poskus z vnosom sledila v enega od ponorov, ki jih najdemo na tej nadmorski višini. Celoten odtok izvira v letu 2015 ocenjujemo na 16,2 milijona m3, pri čemer je približno 25 % prispevalo taljenje snega

Cryptographic Tools for Privacy Preservation

Data permeates every aspect of our daily life and it is the backbone of our digitalized society. Smartphones, smartwatches and many more smart devices measure, collect, modify and share data in what is known as the Internet of Things.Often, these devices don’t have enough computation power/storage space thus out-sourcing some aspects of the data management to the Cloud. Outsourcing computation/storage to a third party poses natural questions regarding the security and privacy of the shared sensitive data.Intuitively, Cryptography is a toolset of primitives/protocols of which security prop- erties are formally proven while Privacy typically captures additional social/legislative requirements that relate more to the concept of “trust” between people, “how” data is used and/or “who” has access to data. This thesis separates the concepts by introducing an abstract model that classifies data leaks into different types of breaches. Each class represents a specific requirement/goal related to cryptography, e.g. confidentiality or integrity, or related to privacy, e.g. liability, sensitive data management and more.The thesis contains cryptographic tools designed to provide privacy guarantees for different application scenarios. In more details, the thesis:(a) defines new encryption schemes that provide formal privacy guarantees such as theoretical privacy definitions like Differential Privacy (DP), or concrete privacy-oriented applications covered by existing regulations such as the European General Data Protection Regulation (GDPR);(b) proposes new tools and procedures for providing verifiable computation’s guarantees in concrete scenarios for post-quantum cryptography or generalisation of signature schemes;(c) proposes a methodology for utilising Machine Learning (ML) for analysing the effective security and privacy of a crypto-tool and, dually, proposes a secure primitive that allows computing specific ML algorithm in a privacy-preserving way;(d) provides an alternative protocol for secure communication between two parties, based on the idea of communicating in a periodically timed fashion

Air Force Institute of Technology Research Report 2019

This Research Report presents the FY19 research statistics and contributions of the Graduate School of Engineering and Management (EN) at AFIT. AFIT research interests and faculty expertise cover a broad spectrum of technical areas related to USAF needs, as reflected by the range of topics addressed in the faculty and student publications listed in this report. In most cases, the research work reported herein is directly sponsored by one or more USAF or DOD agencies. AFIT welcomes the opportunity to conduct research on additional topics of interest to the USAF, DOD, and other federal organizations when adequate manpower and financial resources are available and/or provided by a sponsor. In addition, AFIT provides research collaboration and technology transfer benefits to the public through Cooperative Research and Development Agreements (CRADAs). Interested individuals may discuss ideas for new research collaborations, potential CRADAs, or research proposals with individual faculty using the contact information in this document

Space station systems: A bibliography with indexes (supplement 6)

This bibliography lists 1,133 reports, articles, and other documents introduced into the NASA scientific and technical information system between July 1, 1987 and December 31, 1987. Its purpose is to provide helpful information to the researcher, manager, and designer in technology development and mission design according to system, interactive analysis and design, structural and thermal analysis and design, structural concepts and control systems, electronics, advanced materials, assembly concepts, propulsion, and solar power satellite systems. The coverage includes documents that define major systems and subsystems, servicing and support requirements, procedures and operations, and missions for the current and future Space Station

Deceptive Previews: A Study of the Link Preview Trustworthiness in Social Platforms

Social media has become a primary mean of content and information sharing, thanks to its speed and simplicity. In this scenario, link previews play the important role of giving a meaningful first glance to users, summarizing the content of the shared webpage within their title, description and image. In our work, we analyzed the preview-rendering process, observing how it is possible to misuse it to obtain benign-looking previews for malicious links. Concrete use-case of this research field is phishing and spam spread, considering targeted attacks in addition to large-scale campaigns. We designed a set of experiments for 20 social media platforms including social networks and instant messenger applications and found out how most of the platforms follow their own preview design and format, sometimes providing partial information. Four of these platforms allow preview crafting so as to hide the malicious target even to a tech-savvy user, and we found that it is possible to create misleading previews for the remaining 16 platforms when an attacker can register their own domain. We also observe how 18 social media platforms do not employ active nor passive countermeasures against the spread of known malicious links or software, and that existing cross-checks on malicious URLs can be bypassed through client and server-side redirections. To conclude, we suggest seven recommendations covering the spectrum of our findings, to improve the overall preview-rendering mechanism and increase users’ overall trust in social media platforms