EFFICIENT LABELED SEQUENCE GENERATION FROM SYMBOLIC DIRECTED GRAPHS

This publication describes systems and techniques for more efficiently generating, from a binary file such as an executable or shared library, an application-programming-interface-call (API-call) graph, also referred to as a system call (syscall) graph, and to generate n-grams from the API-call graph. Generally, an API-call graph is generated via static analysis of the wholeprogram control-flow graph of a binary file, and the API-call graph may include symbolic transitions representing internal function calls. Specifically, this publication describes techniques for computing n-grams from an API-call graph that avoids copying of subgraphs of functions represented by symbolic transitions. Avoiding copying of subgraphs of functions represented by symbolic transitions enables faster generation of n-grams with less memory consumption. The generated n-grams can be used in conjunction with machine learning techniques to perform malware detection or other anti-malware techniques

Effective Verification for Low-Level Software with Competing Interrupts

Interrupt-driven software is difficult to test and debug, especially when interrupts can be nested and subject to priorities. Interrupts can arrive at arbitrary times, leading to an exponential blow-up in the number of cases to consider. We present a new formal approach to verifying interrupt-driven software based on symbolic execution. The approach leverages recent advances in the encoding of the execution traces of interacting, concurrent threads. We assess the performance of our method on benchmarks drawn from embedded systems code and device drivers, and experimentally compare it to conventional approaches that use source-to-source transformations. Our results show that our method significantly outperforms these techniques. To the best of our knowledge, our work is the first to demonstrate effective verification of low-level embedded software with nested interrupt

Effective Verification of Low-Level Software with Nested Interrupts

Interrupt-driven software is difficult to test and debug, especially when interrupts can be nested and subject to priorities. Interrupts can arrive at arbitrary times, leading to an explosion in the number of cases to be considered. We present a new formal approach to verifying interrupt-driven software based on symbolic execution. The approach leverages recent advances in the encoding of the execution traces of interacting, concurrent threads. We assess the performance of our method on benchmarks drawn from embedded systems code and device drivers, and experimentally compare it to conventional formal approaches that use source-to-source transformations. Our experimental results show that our method significantly outperforms conventional techniques. To the best of our knowledge, our technique is the first to demonstrate effective formal verification of low-level embedded software with nested interrupts

Identification of High-Quality Transverse Transport Layer Based on Adobe Photoshop Quantification (PSQ) of Reservoir Bitumen: A Case Study of the Lower Cambrian in Bachu-Keping Area, Tarim Basin, China

The Lower Paleozoic carbonate reservoir in the Tarim Basin is a hotspot area for deep oil and gas exploration in China. Although the Lower Cambrian of the Bachu Uplift has not encountered industrial oil flow, rich bitumen has been found there. As the most direct trace of petroleum migration, the effective identification of bitumen is the key to studying the hydrocarbon transportation path. In this study, the Adobe Photoshop quantification (PSQ) method is used to identify the bitumen content in the Xiaoerblak Formation in Well Shutan 1, and, combined with the bitumen characteristics of the Shihuiyao section, a high-quality petroleum transverse transport layer is determined. The results indicate the following: (1) In Well Shutan 1, bitumen is mainly concentrated in the middle and upper parts of the Xiaoerblak Formation with high porosity and high permeability. (2) The shale of the Yuertus Formation in the Shihuiyao section has low hydrocarbon generation potential. However, the overlying Xiaoerblak Formation has developed multistage bituminous veins and bitumen-encapsulated gravels, which is the result of multiple instances of horizontal hydrocarbon migration. (3) After combining the bitumen characteristics of Well Shutan 1 and the Shihuiyao section, it is confirmed that there are high-quality lateral transport conductors in the middle and upper parts of the Xiaoerblak Formation, and the Subsalt Cambrian dolomite reservoir has great exploration potential

Identification of High-Quality Transverse Transport Layer Based on Adobe Photoshop Quantification (PSQ) of Reservoir Bitumen: A Case Study of the Lower Cambrian in Bachu-Keping Area, Tarim Basin, China

The Lower Paleozoic carbonate reservoir in the Tarim Basin is a hotspot area for deep oil and gas exploration in China. Although the Lower Cambrian of the Bachu Uplift has not encountered industrial oil flow, rich bitumen has been found there. As the most direct trace of petroleum migration, the effective identification of bitumen is the key to studying the hydrocarbon transportation path. In this study, the Adobe Photoshop quantification (PSQ) method is used to identify the bitumen content in the Xiaoerblak Formation in Well Shutan 1, and, combined with the bitumen characteristics of the Shihuiyao section, a high-quality petroleum transverse transport layer is determined. The results indicate the following: (1) In Well Shutan 1, bitumen is mainly concentrated in the middle and upper parts of the Xiaoerblak Formation with high porosity and high permeability. (2) The shale of the Yuertus Formation in the Shihuiyao section has low hydrocarbon generation potential. However, the overlying Xiaoerblak Formation has developed multistage bituminous veins and bitumen-encapsulated gravels, which is the result of multiple instances of horizontal hydrocarbon migration. (3) After combining the bitumen characteristics of Well Shutan 1 and the Shihuiyao section, it is confirmed that there are high-quality lateral transport conductors in the middle and upper parts of the Xiaoerblak Formation, and the Subsalt Cambrian dolomite reservoir has great exploration potential

Analysis of Hypersonic Platform-Borne SAR Imaging: A Physical Perspective

The usage of a hypersonic platform for remote sensing application has promising prospects, especially for hypersonic platform-borne synthetic aperture radar (SAR) imaging. However, the high-speed of hypersonic platform will lead to extreme friction between the platform and air, which will cause the ionization of air. The ionized gas forms the plasma sheath wrapped around the hypersonic platform. The plasma sheath will severely affect the propagation of SAR signal and further affect the SAR imaging. Therefore, hypersonic platform-borne SAR imaging should be studied from a physical perspective. In this paper, hypersonic platform-borne SAR imaging under plasma sheath is analyzed. The SAR signal propagation in plasma sheath is computed using scatter matrix method. The proposed SAR signal model is verified by using a ground experiment system. Moreover, the effect of attenuation caused by plasma sheath on SAR imaging is studied under different SAR parameters and plasma sheath. The result shows that attenuation caused by plasma sheath will degrade the SAR imaging quality and even cause the point and area targets to be submerged into the noise. The real SAR images under plasma sheath also illustrate this phenomenon. Furthermore, by studying imaging results under different SAR and plasma parameters, it can be concluded that the severe degradation of SAR imaging quality appears at condition of high plasma sheath electron density and low SAR carrier frequency. The work in this paper will be beneficial for the study of hypersonic platform-borne SAR imaging and design of hypersonic SAR imaging systems in the future

Analysis of Hypersonic Platform-Borne SAR Imaging: A Physical Perspective

The usage of a hypersonic platform for remote sensing application has promising prospects, especially for hypersonic platform-borne synthetic aperture radar (SAR) imaging. However, the high-speed of hypersonic platform will lead to extreme friction between the platform and air, which will cause the ionization of air. The ionized gas forms the plasma sheath wrapped around the hypersonic platform. The plasma sheath will severely affect the propagation of SAR signal and further affect the SAR imaging. Therefore, hypersonic platform-borne SAR imaging should be studied from a physical perspective. In this paper, hypersonic platform-borne SAR imaging under plasma sheath is analyzed. The SAR signal propagation in plasma sheath is computed using scatter matrix method. The proposed SAR signal model is verified by using a ground experiment system. Moreover, the effect of attenuation caused by plasma sheath on SAR imaging is studied under different SAR parameters and plasma sheath. The result shows that attenuation caused by plasma sheath will degrade the SAR imaging quality and even cause the point and area targets to be submerged into the noise. The real SAR images under plasma sheath also illustrate this phenomenon. Furthermore, by studying imaging results under different SAR and plasma parameters, it can be concluded that the severe degradation of SAR imaging quality appears at condition of high plasma sheath electron density and low SAR carrier frequency. The work in this paper will be beneficial for the study of hypersonic platform-borne SAR imaging and design of hypersonic SAR imaging systems in the future

Formal co−validation of low−level hardware/software interfaces

Today's microelectronics industry is increasingly confronted with the challenge of developing and validating software that closely interacts with hardware. These interactions make it difficult to design and validate the hardware and software separately; instead, a verifiable co-design is required that takes them into account. This paper demonstrates a new approach to co-validation of hardware/software interfaces by formal, symbolic co-execution of an executable hardware model combined with the software that interacts with it. We illustrate and evaluate our technique on three realistic benchmarks in which software I/O is subject to hardware-specific protocol rules: a real-time clock, a temperature sensor on an I2C bus, and an Ethernet MAC. We provide experimental results that show our approach is both feasible as a bug-finding technique and scales to handle a significant degree of concurrency in the combined hardware/software model

Remaining Oil Distribution Law and Development Potential Analysis after Polymer Flooding Based on Reservoir Architecture in Daqing Oilfield, China

Polymer flooding has drawn more and more attention in the world for its high incremental oil recovery factor and relative low costs compared with water flooding and other chemically enhanced oil recovery techniques. However, for many oilfields, such as Daqing Oilfield, China, that have already been flooded with polymers, how to further improve recovery remains a big problem. Traditional intralayer, interlayer and plane heterogeneity studies cannot accurately characterize the remaining oil distribution after polymer flooding. To solve this problem, we established a method to quantitatively describe the reservoir’s architecture. Then, the architecture elements were dissected hierarchically and the interface of each architecture level in Daqing Oilfield was identified. The distribution pattern and development potential of the remaining oil after polymer flooding under the influence of reservoir architecture was analyzed. The results show that, regarding the sedimentary process from north to south in Daqing Oilfield, the channel becomes narrower, the thickness decreases, the point bar’s width increases and the thickness of the meandering river decreases. The braided bar scale becomes larger and the thickness becomes smaller in the braided river. According to the reservoir’s architecture, the remaining oil was divided into four categories of plane remaining oil (abandoned channel occlusion type, interfluvial sand body occlusion type, inter-well retention type and well pattern uncontrollable type) and three types of vertical remaining oil (in-layer interlayer occlusion type, rhythm type and gravity type). About 40% of the original oil in place (OOIP) of Daqing Oilfield has not yet been produced, which indicates that there is great potential for development. This study is important for improving oil recovery in polymer-flooded reservoirs

Ratios of peripheral blood mononuclear cells to lncRNA steroid receptor RNA activator as new indicators of metabolic syndrome

Introduction: Metabolic syndrome (MetS) is a clinical syndrome with several characteristics. Steroid receptor RNA activator (SRA) is a long non-coding RNA (lncRNA), which can increase the expression of steroid receptor-dependent gene. This study aimed to explore the changes in metabolic parameters and the predictive value of the peripheral blood mononuclear cells (PBMCs) to SRA ratios as new indicators in subjects with and without MetS in southern China. Material and methods: There were 81 participants (39 with MetS and 42 without MetS) in this cross-sectional study. The expression of lncRNAs in PBMCs was evaluated by quantitative reverse transcription polymerase chain reaction (qRT-PCR). The risks of SRA and PBMCs to SRA ratios contributing to the presence of MetS were estimated by univariate and multivariate logistic regression models. The area under the receiver (AUC) operating characteristic curve was employed to evaluate diagnostic accuracy. Results: MetS was positively correlated with cortisol, interleukin 6 (IL-6), white blood cell to SRA ratio (WTSR),  lymphocyte to SRA ratio (LTSR), monocyte to SRA ratio (MTSR), and PBMC to SRA ratio (PTSR). A receiver operating characteristic (ROC) curve analysis was performed to assess the value of LTSR (OR: 0.722; p < 0.001) for predicting MetS. The area under the curve yielded a cut-off value of 0.483, with a sensitivity of 76.9% and a specificity of 71.4% (p < 0.001). Conclusion: In summary, SRA in PBMCs may be an important biomarker of stress reaction and may play a role in vulnerability to MetS. Also, the lymphocyte to SRA ratio demonstrated high accuracy in the diagnosis of MetS