Towards dynamically monitoring Android applications on non-rooted devices in the wild

Dynamic analysis is an important technique to reveal sensitive behavior of Android apps. Current works require access to the code-level and system-level events (e.g., API calls and system calls) triggered by the running apps and consequently they can only be conducted on in-lab running environments (e.g., emulators and modified OS). The strict requirement of running environment hinders their deployment in scale and makes them vulnerable to anti-analysis techniques. Furthermore, current dynamic analysis of Android apps exploits input generators to invoke app behavior, which, however, cannot provide sufficient code coverage. We propose to dynamically analyze app behavior on non-rooted devices used by the public so that it is possible to analyze dynamically in scale without input generators. By doing so, we also maximize the code coverage since the app behavior is invoked by real users of the apps. To achieve such a goal, we build UpDroid, a system for detecting sensitive behavior without modifying Android OS, rooting the device, or leveraging emulators. UpDroid detects sensitive events by monitoring the changing of public resources on the device, instead of accessing low-level events that require rooting or system modification. To identify the apps that trigger the detected events, UpDroid formulates the identification as a ranking problem and adopts learning to rank technique to solve it. Our experimental results demonstrate that UpDroid can successfully detect the use of 15 out of 26 permissions that are labeled dangerous in the official Android documentation. We also compare UpDroid with API hooking which can theoretically capture all sensitive behavior but requires root permission and system modifications. Results show that UpDroid can still achieve 70% coverage of API hooking even without root permission or any system modifications. © 2018 Association for Computing Machinery

Summertime surface energy balance fluxes at two Beijing sites

Summertime (June to August 2015) radiative and turbulent heat fluxes were measured concurrently at two sites (urban and suburban) in Beijing. The urban site has slightly lower incoming and outgoing shortwave radiation, lower atmospheric transmissivity and a lower surface albedo compared to the suburban site. Both sites receive similar incoming longwave radiation. Although the suburban site had larger daytime outgoing longwave radiation (L_↑), differences in the daily mean L_↑ values are small, as the urban site has higher nocturnal L_↑. Overall, both the midday and daily mean net all-wave radiation (Q^*) for the two sites are nearly equal. However, there are significant differences between the sites in the surface energy partitioning. The urban site has smaller turbulent sensible heat (Q_H) (21-25% of Q^* (midday – daily)) and latent heat (Q_E) fluxes (21-45% of Q^*). Whereas, the suburban proportions of Q^* are Q_H 32-32% and Q_E 39-66%. The daily (midday) mean Bowen ratio (Q_H⁄Q_E ) was 0.56 and 0.49 (0.98 and 0.83) for the urban and suburban sites, respectively. These values are low compared to other urban and suburban areas with similar or larger fractions of vegetated cover. Likely these are caused by the widespread external water use for road cleaning/wetting, greenbelts, and air conditioners. Our suburban site has quite different land cover to most previous suburban studies as crop irrigation supplements rainfall. These results are important in enhancing our understanding of surface–atmosphere energy exchanges in Chinese cities, and can aid the development and evaluation of urban climate models and inform urban planning strategies in the context of rapid global urbanization and climate change

Comment letters to the National Commission on Commission on Fraudulent Financial Reporting, 1987 (Treadway Commission) Vol. 1

https://egrove.olemiss.edu/aicpa_sop/1661/thumbnail.jp

Supplementary data for the article: Mitrović, A. L.; Simonović Radosavljević, J.; Prokopijević, M.; Spasojević, D.; Kovačević, J.; Prodanović, O.; Todorović, B.; Matović, B.; Stanković, M.; Maksimović, V.; Mutavdžić, D.; Skočić, M.; Pešić, M.; Prokić, L.; Radotić, K. Cell Wall Response to UV Radiation in Needles of Picea Omorika. Plant Physiology and Biochemistry 2021, 161, 176–190. https://doi.org/10.1016/j.plaphy.2021.02.007.

Supplementary material for: [https://doi.org/10.1016/j.plaphy.2021.02.007]Related to published version: [http://aspace.agrif.bg.ac.rs/handle/123456789/5816

The growth of network computing : quality adjusted price changes for network servers

In this paper we investigate the evolution of quality adjusted prices for servers motivated by two facts. First, the productivity acceleration in the US economy since the mid 1990s is closely linked to spread of information technology of which networked computing is a large component. Second, the growth of network computing itself has been fostered by the rapid growth in the quality and quantity of the network server market. Like Pakes’ (2003) analysis of the PC market, we show that our preferred version of the hedonic price index (“complete hybrid”) fell much more rapidly than the standard “matched model” price index (the hedonic index fell on average by about 30% per annum compared to 17% p.a. for the matched model). This difference is mainly due to the selection bias in the standard matched model price index due to the exit of obsolete models which would have had the fastest price falls