Air-gapped computers are isolated both logically and physically from all kinds of existing common communication channel, such as USB ports, wireless and wired net- works. Although the feasibility of infiltrating an ai...Air-gapped computers are isolated both logically and physically from all kinds of existing common communication channel, such as USB ports, wireless and wired net- works. Although the feasibility of infiltrating an air-gapped computer has been proved in recent years, data exfiltration from such sys- tems is still considered to be a challenging task. In this paper we present Powermittcr, a novel approach that can exfiltrate data through an air-gapped computer via its power adapter. Our method utilizes the switched-mode pow- er supply, which exists in all of the laptops, desktop computers and servers nowadays. We demonstrate that a malware can indirectly con- trol the electromagnetic emission frequency of the power supply by leveraging the CPU utili- zation. Furthermore, we show that the emitted signals can be received and demodulated by a dedicated device. We present the proof of con- cept design of the power covert channel and implement a prototype of Powermitter consist- ing of a transmitter and a receiver. The trans- mitter leaks out data by using a variant binary frequency shift keying modulation, and the emitted signal can be captured and decoded by software based virtual oscilloscope through such covert channel. We tested Powermitter on three different computers. The experiment re-suits show the feasibility of this power covert channel. We show that our method can also be used to leak data from different types of embedded systems which use switching power supply.展开更多
The paper presents researches on increasing the energetic ＆ economic efficiency of the photovoltaic （PV） conversion by designing and optimizing a dual-axis tracking mechanism that simultaneously changes the positio...The paper presents researches on increasing the energetic ＆ economic efficiency of the photovoltaic （PV） conversion by designing and optimizing a dual-axis tracking mechanism that simultaneously changes the position of the modules using two motor sources. The driving source for the daily motion is a rotary motor, while the elevation motion is performed with a linear actuator. The main task in optimizing the tracking mechanism is to maximize the energetic gain by increasing the solar input and minimizing the energy consumption for tracking. The design strategy aims to identify the optimum angular field for the daily motion, as well as the optimum actuating time in the step-by-step motion. The study is made by developing the virtual prototype of the tracking mechanism, in the mechatronic concept. The virtual prototyping platform includes the following software solutions： CATIA （Computer Aided Tri-Dimensional Interface Application）--to create the solid model, which contains information about the mass ＆ inertia properties of the parts, ADAMS （Automatic Dynamic Analysis of Mechanical Systems）/View--to model the mechanical structure of the solar tracker, and EASY5 ＆ ADAMS/Controls-for the control system design.展开更多
基金supported by the National High Technology Research and Development Program of China ("863" Program) (Grant No. 2015AA016002)the National Basic Research Program of China ("973" Program) (Grant No. 2014CB340600)
文摘Air-gapped computers are isolated both logically and physically from all kinds of existing common communication channel, such as USB ports, wireless and wired net- works. Although the feasibility of infiltrating an air-gapped computer has been proved in recent years, data exfiltration from such sys- tems is still considered to be a challenging task. In this paper we present Powermittcr, a novel approach that can exfiltrate data through an air-gapped computer via its power adapter. Our method utilizes the switched-mode pow- er supply, which exists in all of the laptops, desktop computers and servers nowadays. We demonstrate that a malware can indirectly con- trol the electromagnetic emission frequency of the power supply by leveraging the CPU utili- zation. Furthermore, we show that the emitted signals can be received and demodulated by a dedicated device. We present the proof of con- cept design of the power covert channel and implement a prototype of Powermitter consist- ing of a transmitter and a receiver. The trans- mitter leaks out data by using a variant binary frequency shift keying modulation, and the emitted signal can be captured and decoded by software based virtual oscilloscope through such covert channel. We tested Powermitter on three different computers. The experiment re-suits show the feasibility of this power covert channel. We show that our method can also be used to leak data from different types of embedded systems which use switching power supply.
文摘The paper presents researches on increasing the energetic ＆ economic efficiency of the photovoltaic （PV） conversion by designing and optimizing a dual-axis tracking mechanism that simultaneously changes the position of the modules using two motor sources. The driving source for the daily motion is a rotary motor, while the elevation motion is performed with a linear actuator. The main task in optimizing the tracking mechanism is to maximize the energetic gain by increasing the solar input and minimizing the energy consumption for tracking. The design strategy aims to identify the optimum angular field for the daily motion, as well as the optimum actuating time in the step-by-step motion. The study is made by developing the virtual prototype of the tracking mechanism, in the mechatronic concept. The virtual prototyping platform includes the following software solutions： CATIA （Computer Aided Tri-Dimensional Interface Application）--to create the solid model, which contains information about the mass ＆ inertia properties of the parts, ADAMS （Automatic Dynamic Analysis of Mechanical Systems）/View--to model the mechanical structure of the solar tracker, and EASY5 ＆ ADAMS/Controls-for the control system design.
