Risk Assessment of Power System Security based on a Hybrid Optimization GP Method

Xiaobin Wu,Hui Li,Xiaolu Chen 보안공학연구지원센터 2015 International Journal of Security and Its Applicat Vol.9 No.12

In this paper, we propose a hybrid optimization algorithm based on Improved Differential Evolution (IDE) algorithm and Gaussian Process (GP). Firstly, the paper constructs the assessment index system using Fault Tree Analysis (FTA) based on the summary and classification of the factors that could affect the power system security. Secondly, establish the risk assessment model of power system security based on the hybrid optimization GP algorithm. Hyper-parameter of GP has a great influence on construction of evaluation model, while conjugate gradient method which is usually used has strong dependence on initial values and is easy to fall into local optimal solution. So the paper uses the IDE algorithm for the traditional Hyper-parameter optimization, then the optimal Hyper-parameter is used to construct evaluation model for power grid security risk assessment. In the process of improvement, this paper adds the local search (Bees accelerated evolution operation) and global search (Bees scout operation) thought of ABC algorithm into the DE algorithm to reduce the population size required by the algorithm. After that, do the risk assessment of power system by using the established assessment model. Finally, do the simulation experiments using the standard data IEEE-39 and IEEE-118 bus example, and besides compare the IDE-GP with other optimization model like ABC-GP, DE-GP, MA-GP, GA-GP, and the experimental results show that hybrid optimization algorithm has better performance in accuracy while the time-consuming difference is minor. The validity of the proposed method is also demonstrated.

Ginsenoside Rg3 nanoparticles with permeation enhancing based chitosan derivatives were encapsulated with doxorubicin by thermosensitive hydrogel and anti-cancer evaluation of peritumoral hydrogel injection combined with PD-L1 antibody

Wu Hao,Wei Guoli,Luo Lixia,Li Lingchang,Gao Yibo,Tan Xiaobin,Wang Sen,Chang Haoxiao,Liu Yuxi,Wei Yingjie,Song Jie,Zhang Zhenhai,Huo Jiege 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00

Combination of chemotherapy and immune checkpoint inhibitor therapy has greatly improved the anticancer effect on multiple malignancies. However, the efficiency on triple-negative breast cancer (TNBC) is limited, since most patients bear “cold” tumors with low tumor immunogenicity. Doxorubicin (DOX), one of the most effective chemotherapy agents, can induce immunogenic cell death (ICD) and thus initiating immune response.In this study, to maximize the ICD effect induced by DOX, chitosan and cell-penetrating peptide (R6F3)-modified nanoparticles (PNPs) loaded with ginsenoside Rg3 (Rg3) were fabricated using the self-assembly technique, followed by co-encapsulation with DOX based on thermo-sensitive hydrogel. Orthotopic tumor model and contralateral tumor model were established to observe the antitumor efficacy of the thermo-sensitive hydrogel combined with anti-PD-L1 immunotherapy, besides, the biocompatibility was also evaluated by histopathological.Rg3-PNPs strengthened the immunogenic cell death (ICD) effect induced by DOX. Moreover, the hydrogel co-loading Rg3-PNPs and DOX provoked stronger immune response in originally nonimmunogenic 4T1 tumors than DOX monotherapy. Following combination with PD-L1 blocking, substantial antitumor effect was achieved due to the recruitment of memory T cells and the decline of adaptive PD-L1 enrichment.The hydrogel encapsulating DOX and highly permeable Rg3-PNPs provided an efficient strategy for remodeling immunosuppressive tumor microenvironment and converting immune “cold” 4T1 into “hot” tumors.

Active monitoring of pipeline tapered thread connection based on time reversal using piezoceramic transducers

Xiaobin Hong,Gangbing Song,Jiaobiao Ruan,Zhimin Zhang,Sidong Wu,Guixiong Liu 국제구조공학회 2016 Smart Structures and Systems, An International Jou Vol.18 No.4

The monitoring of structural integrity of pipeline tapered thread connections is of great significance in terms of safe operation in the industry. In order to detect effectively the loosening degree of tapered thread connection, an active sensing method using piezoceramic transducers was developed based on time reversal technique in this paper. As the piezoeramic transducers can be either as actuators or sensors to generate or detect stress waves, the energy transmission for tapered thread connection was analyzed. Subsequently, the detection principle for tapered thread connection based on time reversal was introduced. Finally, the inherent relationship between the contact area and tightness degree of tapered thread connection for the pipe structural model was investigated. Seven different contact area scenarios were tested. Each scenario was created by loosening connectors ranging from 3 turns to 4.5 turns in the right tapered threads when the contact area in the left tapered threads were 4.5 turns. The experiments were separately conducted with a highly noisy environment and various excitation signal amplitudes. The results show the focused peaks based on time reversal have the monotonously rising trend with the increase of the contact areas of tapered threads within an acceptable monitoring resolution for metal pipes. Compared with the energy method, the proposed time reversal based method to monitor tapered threads loosening demonstrates to be more robust in rejecting noise in Structural Health Monitoring (SHM) applications.

ER-Fuzz:Conditional Code Removed Fuzzing

( Xiaobin Song ),( Zehui Wu ),( Yan Cao ),( Qiang Wei ) 한국인터넷정보학회 2019 KSII Transactions on Internet and Information Syst Vol.13 No.7

Coverage-guided fuzzing is an efficient solution that has been widely used in software testing. By guiding fuzzers through the coverage information, seeds that generate new paths will be retained to continually increase the coverage. However, we observed that most samples follow the same few high-frequency paths. The seeds that exercise a high-frequency path are saved for the subsequent mutation process until the user terminates the test process, which directly affects the efficiency with which the low-frequency paths are tested. In this paper, we propose a fuzzing solution, ER-Fuzz, that truncates the recording of a high-frequency path to influence coverage. It utilizes a deep learning-based classifier to locate the high and low-frequency path transfer points; then, it instruments at the transfer position to promote the probability low-frequency transfer paths while eliminating subsequent variations of the high-frequency path seeds. We implemented a prototype of ER-Fuzz based on the popular fuzzer AFL and evaluated it on several applications. The experimental results show that ER-Fuzz improves the coverage of the original AFL method to different degrees. In terms of the number of crash discoveries, in the best case, ER-Fuzz found 115% more unique crashes than did AFL. In total, seven new bugs were found and new CVEs were assigned.

Thermal-Assisted Single Point Incremental Forming of Jute Fabric Reinforced Poly(lactic acid) Biocomposites

Chang Hou,Xiaobin Su,Xiongqi Peng,Xianfeng Wu,Dongqing Yang 한국섬유공학회 2020 Fibers and polymers Vol.21 No.10

This paper developed a thermal-assisted single point incremental forming (SPIF) method for biodegradablecomposite sheets made from jute woven fabric and polylactic acid (PLA) resin. A forming device equipped with a thermalradiation plate was designed for the SPIF of the composite sheets on a three-axis CNC milling machine. A three-tier-platemethod in which the composite sheet was sandwiched between an iron plate and an alumina plate was adopted to clamp thecomposite sheet. The proposed SPIF method was demonstrated on forming of a truncated pyramid part. The effects ofclamping method, toolpath, step size and thickness on the formability of the composite were investigated. It was found thatthe three-tier-plate fixture method was crucial for the successful implementation of the SPIF of the composite. The toolpathhad a significant effect on the forming depth. While the surface quality was mainly determined by the step size. The thicknessof the composite sheet had a positive effect on is forming depth.

Experimental Research on Double-walled Carbon Nanotubes by Using Tip-enhanced Raman Spectroscopy

Mingqian Zhang,,Xiaobin Wu,Jia Wang,Qian Tian 한국물리학회 2010 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.56 No.4

In this research, a transmission mode tip-enhanced Raman spectroscopy (TERS) system is set up. Using this self-made TERS system, topographic images and corresponding TERS spectra of positions of interest on a thin film of dispersed double-walled carbon nanotubes (DWNTs) are investigated. The Raman enhancement factor is estimated to be 3.6 × 102. TERS spectra of different measured positions show distinct Raman features that represent their different components and structures. This indicates that characterization of DWNTs and Raman spectral recognition can be realized. The experimental results indicate that there is a peak shift between the TERS and the far-field spectrum in radial breathing mode region, which may be attributed to a combination of the tip’s mechanical pressure and the interaction between the two layer tube walls of the DWNTs.

Dynamic stiffness analysis of steel-concrete composite beams

Jun Li,Qiji Huo,Xiaobin Li,Xiangshao Kong,Weiguo Wu 국제구조공학회 2014 Steel and Composite Structures, An International J Vol.16 No.6

An exact dynamic stiffness method is introduced for investigating the free vibration characteristics of the steel-concrete composite beams consisting of a reinforced concrete slab and a steel beam which are connected by using the stud connectors. The elementary beam theory is used to define the dynamic behaviors of the two beams and the relative transverse deformation of the connectors is included in the formulation. The dynamic stiffness matrix is formulated from the exact analytical solutions of the governing differential equations of the composite beams in undamped free vibration. The application of the derived dynamic stiffness matrix is illustrated to predict the natural frequencies and mode shapes of the steel-concrete composite beams with seven boundary conditions. The present results are compared to the available solutions in the literature whenever possible.

Automatic Test Case Generation for BPEL Using Stream X-Machine

Chunyan Ma,Junsheng Wu,Tao Zhang,Yunpeng Zhang,Xiaobin Cai 보안공학연구지원센터(IJUNESST) 2008 International Journal of u- and e- Service, Scienc Vol.1 No.1

Coupling effects of vortex-induced vibration for a square cylinder at various angles of attack

Deqian Zheng,Wenyong Ma,Xiaobin Zhang,Wei Chen,Junhao Wu 한국풍공학회 2022 Wind and Structures, An International Journal (WAS Vol.34 No.5

Vortex-induced vibration (VIV) is a significant concern when designing slender structures with square cross sections. VIV strongly depends on structural dynamics and flow states, which depend on the conditions of the approaching flow and shape of a structure. Therefore, the effects of the angle of attack on the coupling effects of VIV for a square cylinder are expected to be significant in practice. In this study, the aerodynamic forces for a fixed and elastically mounted square cylinder were measured using wind pressure tests. Aerodynamic forces on the stationary cylinder are firstly discussed by comparisons of variation of statistical aerodynamic force and wind pressure coefficient with wind angle of attack. The coupling effect between the aerodynamic forces and the motion of the oscillating square cylinder by VIV is subsequently investigated in detail at typical wind angels of attack with occurrence of three typical flow regimes, i.e., leading-edge separation, separation bubble (reattachment), and attached flow. The coupling effect are illustrated by discussing the onset of VIV, characteristics of aerodynamic forces during VIV, and interaction between motion and aerodynamic forces. The results demonstrate that flow states can be classified based on final separation points or the occurrence of reattachment. These states significantly influence coupling effects of the oscillating cylinder. Vibration enhances vortex shedding, which creates strong fluctuations in aerodynamic forces. However, differences in the lock-in range, aerodynamic force, and interaction process for angles of attack smaller and larger than the critical angle of attack revealed noteworthy characteristics in the VIV of a square cylinder.

A novel stricture prevention technique in blunt urethral injury: A multi-center retrospective observational study

Yang Mi,Jingyu Wang,Jinfeng Wu,Xiaopeng Wang,Bin Yang,Ruimin Ren,Yangang Zhang,Xiaobin Yuan,Xuhui Zhang 대한비뇨의학회 2022 Investigative and Clinical Urology Vol.63 No.1

Purpose: Bulbar injury is the most common type of urethral injury. This study investigated the efficacy and safety of a novel technique, local urethral flushing, in preventing stricture formation after blunt bulbar urethra injuries. Materials and Methods: This retrospective study included 205 males diagnosed with straddle injury-induced bulbar urethra injury at the Shanxi Bethune Hospital and First Hospital of Shanxi Medical University between January 2015 and January 2019. Patients were diagnosed by retrograde urethrography and classified as partial or complete urethral rupture according to the urethral integrity after injury. Complete urethral rupture patients received suprapubic cystostomy and received urethroplasty 3 months later. Patients with partial urethral rupture underwent endoscopic urethral realignment by cystoscopic guide-wire guided catheterization. Patients with both injury types were divided into 3 groups. The treatment groups received urethral flushing with 0.05% dexamethasone through a secondary ureteral catheter that locked at the urethral lesion. The blank control groups received normal saline. The negative control groups had only a single ureteral catheter placed. Patients were assessed for pain during catheterization, infection, and stenosis, and followed for at least 2 years. Results: Stenosis rates and length were significantly reduced in the normal saline groups, and even further reduced in the dexamethasone groups. The negative control groups had significantly higher infection rates than patients in the dexamethasone or saline groups. Conclusions: Local urethral flushing with dexamethasone could significantly decrease urethral stenosis rates and severity without increasing patients’ discomfort or infection risk.