Outsourcing image management to a cloud should not only protect the confidentiality of image data, but also maintain the capability of reverse image search, which requires identifying the existing stored images that are similar to an input image. Previous studies build on cryptographic approaches to realize reverse image search on encrypted images, yet failing to achieve either security or performance. This paper explores trusted image search, which uses Intel SGX to realize reverse image search in an enclave, in order to provide security guarantees via SGX while performing search on plain data (inside the enclave) for performance. However, due to the resource limits of SGX, directly realizing the search process in the enclave incurs high performance overhead. We present TRUSTSEARCH, which implements various design approaches to mitigate the resource overhead of SGX. We evaluate TRUSTSEARCH using real-world image datasets, and show that it outperforms state-of-the-art approaches for search performance while preserving space efficiency for the enclave.

This study investigates the large-scale ionospheric traveling disturbances (LSTIDs) over North America and Europe associated with the intense geomagnetic storm in May 2024, utilizing Total Electron Content (TEC) data derived from ground-based Global Navigation Satellite System (GNSS) stations. The findings reveal that the observed LSTIDs in both regions exhibited an unusually prolonged duration, lasting for over 10 hours from 17:00 UT on May 10 to 03:30 UT on May 11, 2024. This extended duration may be attributed to the continuous triggering of LSTIDs by auroral energy input during the geomagnetic storm. Additionally, significant differences in propagation characteristics, including velocities, azimuths, wavelengths, and traveling distances of LSTIDs, were observed between the two regions. These disparities in LSTID parameters are likely due to variations in the magnitude of energy input in the polar regions and local time differences in North America (14:00 LT) and Europe (19:00 LT), cause diurnal electron-density contrast influence LSTIDs propagation.

The Gravity Recovery and Climate Experiment (GRACE) and the Ice, Cloud, and land Elevation Satellite (ICESat) missions can estimate the ice mass changes in Greenland. The GRACE monthly time-varying gravity filed solution can be used to infer the redistribution of temporal redistribution with a limited spatial resolution of 300-500 km, while the ICESat measurements can estimate the elevation variations of ice-sheet with high-precision but have a limited temporal coverage and the assumption of snow/ice density when used to monitor the mass change of Greenland ice sheet. The combination of these two independent measurements will overcome each shortcoming, improving not only the resolution capability but also the reliability of estimated results of ice mass changes. In this paper, glacier variations in Greenland are investigated by joint GRACE and ICESat measurements. The ice mass change rate in Greenland is - 142.14 Gt/yr, and the acceleration is -16.28 Gt/yr2from GRACE during January 2003 to June 2007, while the total ice mass loss is at 173.03Gt/yr at the same period from ICESat measurements. The combined estimation of Greenland ice sheet loss rate is -157.59 Gt/yr fromGRACE and ICESat with more smooth and high resolution.