HyperLink: Virtual Machine Introspection and Memory Forensic Analysis without Kernel Source Code

Virtual Machine Introspection (VMI) is an approach to inspecting and analyzing the software running inside a virtual machine from the hypervisor. Similarly, memory forensics analyzes the memory snapshots or dumps to understand the runtime state of a physical or virtual machine. The existing VMI and memory forensic tools rely on up-to-date kernel information of the target operating system (OS) to work properly, which often requires the availability of the kernel source code. This requirement prevents these tools from being widely deployed in real cloud environments. In this paper, we present a VMI tool called HyperLink that partially retrieves running process information from a guest virtual machine without its source code. While current introspection and memory forensic solutions support only one or a limited number of kernel versions of the target OS, HyperLink is a one-for-many introspection and forensic tool, i.e., it supports most, if not all, popular OSes regardless of their versions. We implement both online and offline versions of HyperLink.We validate the efficacy of HyperLink under different versions of Linux, Windows, FreeBSD, and Mac OS X. For all the OSes we tested, HyperLink can successfully retrieve the process information in one minute or several seconds. Through online and offline analyses, we demonstrate that HyperLink can help users detect real-world kernel rootkits and play an important role in intrusion detection. Due to its version-agnostic property, HyperLink could become the first introspection and forensic tool that works well in autonomic cloud computing environments

Investigation of a refrigeration system based on combined supercritical CO2 power and transcritical CO2 refrigeration cycles by waste heat recovery of engine

The majority of the energy in the fuel burned in the internal combustion engines is lost in the form of waste heat. To address this issue, waste heat recovery technology has been proposed to increases the overall efficiency of engine. This paper investigates a heat driven cooling system based on a supercritical CO2 (S-CO2) power cycle integrated with a transcritical CO2 (T-CO2) refrigeration cycle, aiming to provide an alternative to the vapour absorption cooling system. The combined system is proposed to produce cooling for food preservation on a refrigerated truck by waste heat recovery of engine. In this system, the S-CO2 absorbs heat from the exhaust gas and the generated power in the expander is used to drive the compressors in both S-CO2 power cycle and T-CO2 refrigeration cycle. Unlike the bulky vapour absorption cooling system, both power plant and vapour compression refrigerator can be scaled down to a few kilo Watts, opening the possibility for developing small-scale waste heat driven cooling system that can be widely applied for waste heat recovery from IC engines of truck, ship and trains.A new layout sharing a common cooler is also studied. The results suggest that the concept of S-CO2/T-CO2 combined cycle sharing a common cooler has comparable performance and it is thermodynamically feasible. The heat contained in exhaust gas is sufficient for the S-CO2/T-CO2 combined system to provide enough cooling for refrigerated truck cabinet whose surface area is more than 105 m2

Silicon-chip source of bright photon pairs

Integrated quantum photonics relies critically on the purity, scalability, integrability, and flexibility of a photon source to support diverse quantum functionalities on a single chip. Here we report a chip-scale photon-pair source on the silicon-on-insulator platform that utilizes dramatic cavity-enhanced four-wave mixing in a high-Q silicon microdisk resonator. The device is able to produce high-quality photon pairs at different wavelengths with a high spectral brightness of 6.24×10^7 pairs/s/mW^2/GHz and photon-pair correlation with a coincidence-to-accidental ratio of 1386 ± 278 while pumped with a continuous-wave laser. The superior performance, together with the structural compactness and CMOS compatibility, opens up a great avenue towards quantum silicon photonics with capability of multi-channel parallel information processing for both integrated quantum computing and long-haul quantum communication

Effects of experimental parameters on elemental analysis of coal by laser-induced breakdown spectroscopy

The purpose of this work is to improve the precision of the elemental analysis of coal using laser-induced breakdown spectroscopy (LIBS). The LIBS technique has the ability to allow simultaneous elemental analysis and on-line determination, so it could be used in the elemental analysis of coal. Organic components such as C, H, O, N and inorganic components such as Ca, Mg, Fe, Al, Si, Ti, Na, and K of coal have been identified. The precision of the LIBS technique depends strongly on the experimental conditions, and the choice of experimental parameters should be aimed at optimizing the repeatability of the measurements. The dependences of the relative standard deviation (RSD) of the LIBS measurements on the experimental parameters including the sample preparation parameters, lens-to-sample distance, sample operation mode, and ambient gas have been investigated. The results indicate that the precision of LIBS measurements for the coal sample can be improved by using the optimum experimental parameters

Influence of coal characteristics on laser-induced plasmas

peer reviewedEight kinds of typical coal samples were chosen for studying the influence of coal characteristics on laser—induced plasmas．Element analysis and industry analysis were carried out for every sample．Experimental study on the interaction between laser and different coal samples was completed，and factors affecting laser plasma were analyzed，such as coal moisture and coal dust．The experiment result indicates that the coal samples with different coalification degrees have different plasma time—resolved spectral characteristics，all of them tend to rise at the beginning of plasma formation (< 1us)，then with the decay of plasmas emission．they tend to decrease in about 1us，while secondary ionization occurs in highly coalificated coals after 2 us．The plasma temperature differs from one kind to another，the higher the coalification degree is，the higher the plasma temperature will be

Investigation on Laser-induced Breakdown Spectroscopy of Potassium Chloride Solution

peer reviewedThe experimental setup for laser—induced breakdown spectroscopy test was designed with pulsed Nd：YAG laser，spectrograph and ICCD and so on．Furthermore the potassium chloride solution spectra signals were detected by this setup．The spectra lines of the trace elements such as natrium (20mg／1)，magnesium(1 mg／1)，calcium(3 mg／1)are recorded．Experiment results show that delay time is one of the important parameters when qualitative analysis．It is easy for LIBS technology to detect multi—elements simultaneity if delay time is appropriate，and qualitative analysis has demonstrated that the feasibility of detecting trace poisonous metals in waste water using LIBS

Matrix Effect on Laser Induced Breakdown Spectroscopy of Fine Coal

peer reviewedThe feasibility of laser—induced breakdown spectroscopy as a diagnostic tool for elementary analysis was documented widely,as well as the matrix effect of target material was proved to be remarkable impact on the spectral analysis． The influence of physical characteristics of fine coal，including particle size and area density，on the emission spectrum was surveyed，such as spectral intensity,standard deviation of characteristic spectrum and the detection threshold．An intense laser radiation with a wavelength of 1064 nm was used to ablate fine coal to form plasma plume，and the emission spectrum emitted as the plasma cooling of was analyzed by high—resolution echelle grating spectrometer coupled to intensified CCD camera．The results suggest that moderate particle size and material density are more advantageous to quantitative analysis of coal by laser—induced breakdown spectroscopy than the smallest or biggest size，which can be interpretable by heat—transfer mechanism in target after a shot of laser pulse