Analysis On Security and Dependability for IED System in SAS

관창(Qiang Guan),한승수(Seung-Soo Han),이승재(Seung-Jae Lee) 대한전기학회 2006 대한전기학회 학술대회 논문집 Vol.2006 No.11

As a general rule for evaluating dependability of a system, reliability is commonly considered which barely pays attention to the system behavior, however the estimation is based on the assumption of a fault-frost system, which may be impracticable and inaccurate especially for complicated system. This paper introduces a security and dependability integrated approach to analyze the availability of a fault-active system both from dependability and security points of view. Two fault modes involved are discussed about the impairment to the system reliance. The approach can be well applied to estimate and quantity the attribute of system robustness with the help of Markov chain process, which is good at solving status related problem. The comparison result between dual system and IEC61850-based almighty backup system is shown to support the suggested approach.

The application of IEC61850 in a new anti-fault substation system

관창(Qiang Guan),한승수(Seung-Soo Han) 대한전기학회 2006 대한전기학회 학술대회 논문집 Vol.2006 No.7

The compatibility between different automation devices hasn't been difficult any longer while the new standard IEC61850 is imposed which provides efficient implementation on both embedded and non-embedded system. While implementing the substation automation, different devices from different company may be an obstacle to system designing. However, with the help of IEC61850 this problem can be neglected. In this paper the newest development of the demo system based on IEC61850 will be introduced.

Reconstruction of the Cervical Lateral Mass Using 3-Dimensional-Printed Prostheses

Qiang Jian,Zhenlei Liu,Wanru Duan,Jian Guan,Fengzeng Jian,Zan Chen 대한척추신경외과학회 2022 Neurospine Vol.19 No.1

Objective: This study aimed to investigate the outcome of using 3-dimensional (3D)-printed prostheses to reconstruct a cervical lateral mass to maintain cervical stability. Methods: We retrospectively analyzed data of 7 patients who underwent cervical lateral mass reconstruction using a 3D-printed prosthesis, comprising axial and subaxial lateral mass reconstruction in 2 and 5 patients, respectively. Bilateral mass was reconstructed in 1 patient and unilateral mass in the remaining 6 patients. Results: Using a 3D-printed lateral mass prosthesis, internal fixation was stable for all 7 patients postoperatively. No implant-related complications such as prosthesis loosening, displacement, and compression were observed at the last follow-up. Conclusion: Reconstruction of the lateral mass structure is beneficial in restoring load transfer in the cervical spine under physiological conditions. A 3D-printed prosthesis can be considered a good option for reconstruction of the lateral mass as fusion was achieved, with no subsequent complications observed.

Location Distribution of Fistulas and Surgical Strategies for Spinal Extradural Meningeal Cysts: A Retrospective Analysis of 30 Cases at a Single Center

Qiang Jian,Gang Song,Zhenlei Liu,Wanru Duan,Jian Guan,Fengzeng Jian,Zan Chen 대한척추신경외과학회 2022 Neurospine Vol.19 No.1

Objective: This study aimed to illustrate the features of fistula location distribution, surgical strategies, and outcomes in spinal epidural meningeal cysts (SEMCs). Methods: The authors searched and reviewed the medical records for cases of SEMCs. Imaging features, operative reports, and media were reviewed to accurately describe the surgical techniques employed. We recorded the level and laterality of the fistula according to the operative report and the media. Consistency analysis was performed on the dominant laterality of the cyst on preoperative axial magnetic resonance imaging and laterality of the fistula in the operative media or report. When cyst and fistula lateralities were the same, they were considered consistent. Finally, the Japanese Orthopedic Association (JOA) score was used to obtain patient-reported results at each follow-up. Results: Thirty patients with SEMCs were identified. Fistula repair was performed in all patients. Two patients experienced cyst recurrence after surgery and were repaired during the second surgery. Based on imaging findings, SEMCs mostly occurred in the thoracolumbar junction. Most of the fistulas (87.88%) were at the T12 or L1 levels. In patients with multiple adjacent SEMCs, the fistula may be at one end of the cyst rather than in the middle level of the cyst. A fistula laterality of 72.72% was consistent with cyst laterality. The JOA improvement rate was 61.84% ± 26.63%. Conclusion: Most fistulas were always located at the T12–L1 level as well as the middle level of the cyst, which is always consistent with cyst laterality. In patients with multiple adjacent SEMCs, the fistula may be at one end of the cyst. Cleft closure is key to healing SEMCs.

Exploring Flow Characteristics in IPv6: A Comparative Measurement Study with IPv4 for Traffic Monitoring

( Qiang Li ),( Tao Qin ),( Xiaohong Guan ),( Qinghua Zheng ) 한국인터넷정보학회 2014 KSII Transactions on Internet and Information Syst Vol.8 No.4

With the exhaustion of global IPv4 addresses, IPv6 technologies have attracted increasing attentions, and have been deployed widely. Meanwhile, new applications running over IPv6 networks will change the traditional traffic characteristics obtained from IPv4 networks. Traditional models obtained from IPv4 cannot be used for IPv6 network monitoring directly and there is a need to investigate those changes. In this paper, we explore the flow features of IPv6 traffic and compare its difference with that of IPv4 traffic from flow level. Firstly, we analyze the differences of the general flow statistical characteristics and users` behavior between IPv4 and IPv6 networks. We find that there are more elephant flows in IPv6, which is critical for traffic engineering. Secondly, we find that there exist many one-way flows both in the IPv4 and IPv6 traffic, which are important information sources for abnormal behavior detection. Finally, in light of the challenges of analyzing massive data of large-scale network monitoring, we propose a group flow model which can greatly reduce the number of flows while capturing the primary traffic features, and perform a comparative measurement analysis of group users` behavior dynamic characteristics. We find there are less sharp changes caused by abnormity compared with IPv4, which shows there are less large-scale malicious activities in IPv6 currently. All the evaluation experiments are carried out based on the traffic traces collected from the Northwest Regional Center of CERNET (China Education and Research Network), and the results reveal the detailed flow characteristics of IPv6, which are useful for traffic management and anomaly detection in IPv6.

A facile method to synthesize magnetic nanoparticles chelated with Copper(II) for selective adsorption of bovine hemoglobin

Huiyuan Guan,Jundong Wang,Siyuan Tan,Qiang Han,Qionglin Liang,Mingyu Ding 한국화학공학회 2020 Korean Journal of Chemical Engineering Vol.37 No.6

A novel and uncomplicated synthesis method of Cu2+-chelating with carboxyl groups that directly-modified NiFe2O4 magnetic microspheres (NiFe2O4-PAA-Cu2+) was fabricated for selective enrichment and separation of bovine hemoglobin (BHb). First, a carboxyl group directly-modified on NiFe2O4 magnetic microspheres was gained through a facile one-pot solvothermal method. Second, Cu2+ from CuSO4 was brought into use to react with carboxyl groups under mechanical stirring at room temperature. The resulting magnetic microspheres were characterized by distinct instruments that included transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), vibrating sample magnetometer (VSM) and scanning electron microscope (SEM) to examine the size, morphology, composition and magnetization characterization. The results indicated that the NiFe2O4-PAA-Cu2+ microspheres exhibited good saturation magnetization (36.686 emu g1), which can facilitate magnetic separation under the help of an outside magnetic field. Also, good dispersion and high adsorption ability to BHb (783.53mg g1) can be applied to selective enrichment for bovine hemoglobin and used for selective sorption of BHb protein in bovine blood samples.

Dynamic behavior analysis of push-the-bit rotary steerable bottom hole assembly

Zhi-chuan Guan,Heng Wang,Yu-cai Shi,Wei-qing Chen,Guo-shan Zhao,Jian-yun Wang,Guang-qiang Cao 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.4

Rotary steerable drilling technology is currently an advanced technology in the field of drilling engineering. A good understanding of dynamic behavior of rotary steerable system will benefit the drilling progress. Aimed at push-the-bit type of rotary steerable tool, finite element method was employed to model the rotary steerable bottom hole assembly (RSBHA) and establish the motion equation. Contact interaction between drill string and wellbore wall was analyzed and taken as the constraint condition in solving RSBHA motion equation. Force applied by steering pads was as the external force acting at the pads node. Then RSBHA motion state and bit lateral force were obtained by using Newmark method to solve the motion equation. A case was given and effects of influencing factors were analyzed. The results show that stick-slip phenomenon occurs under 60 r/min rotary speed condition and disappears when rotary speed rises to 90 r/min. Fully developed backward whirl comes into being at the near-bit stabilizer when rotary speed increases to 120 r/min. High weight on bit intensifies bit torsional vibration while larger pads’ steering force decreases the bit torsional vibration. Upper stabilizer plays a part in weakening RSBHA backward whirl under high rotary speed condition but reduces the inclination force. Time average of bit lateral force is mainly determined by pads’ steering force. Based on the results, corresponding suggestions were proposed to make the RSBHA be better used in the field applications.

Parallel Multi-task Cascade Convolution Neural Network Optimization Algorithm for Real-time Dynamic Face Recognition

( Bin Jiang ),( Qiang Ren ),( Fei Dai ),( Tian Zhou ),( Guan Gui ) 한국인터넷정보학회 2020 KSII Transactions on Internet and Information Syst Vol.14 No.10

Due to the angle of view, illumination and scene diversity, real-time dynamic face detection and recognition is no small difficulty in those unrestricted environments. In this study, we used the intrinsic correlation between detection and calibration, using a multi-task cascaded convolutional neural network(MTCNN) to improve the efficiency of face recognition, and the output of each core network is mapped in parallel to a compact Euclidean space, where distance represents the similarity of facial features, so that the target face can be identified as quickly as possible, without waiting for all network iteration calculations to complete the recognition results. And after the angle of the target face and the illumination change, the correlation between the recognition results can be well obtained. In the actual application scenario, we use a multi-camera real-time monitoring system to perform face matching and recognition using successive frames acquired from different angles. The effectiveness of the method was verified by several real-time monitoring experiments, and good results were obtained.

Effect of Degumming Methods on the Degradation Behavior of Silk Fibroin Biomaterials

Luping Wang,Zuwei Luo,Qiang Zhang,Yupin Guan,Junyi Cai,Renchuan You,Xiufang Li 한국섬유공학회 2019 Fibers and polymers Vol.20 No.1

Degradation behavior is a key consideration in the field of silk fibroin (SF) biomaterials. Degumming to remove sericin is a prerequisite for SF purification; however, the impact of degumming on the degradation behavior of SF biomaterials has not been established. In this study, two different degumming systems, Na2CO3 and NaHCO3, were used. Na2CO3 exhibited higher degumming efficiency but caused greater degradation of the fibroin. The results demonstrated that NaHCO3 degumming could afford regenerated SF with higher molecular weight, resulting in SF films with higher mechanical strengths. The enzymatic degradation behaviors indicated that the SF films prepared by the Na2CO3 degumming process showed faster degradation, revealing that the choice of degumming method has a substantial impact on the biodegradation of SF-based materials. The results showed that manipulating the degumming conditions can be used to tune the molecular weight of the SF, in turn providing control over the degradation rate of SF biomaterials.

Robust Digital Image Watermarking Algorithm Using RBF Neural Networks in DWT domain

Piao, Cheng-Ri,Guan, Qiang,Choi, Jun-Rim,Han, Seung-Soo Korean Institute of Intelligent Systems 2007 INTERNATIONAL JOURNAL of FUZZY LOGIC and INTELLIGE Vol.7 No.2

This paper proposes a new watermarking scheme in which a logo watermark is embedded into the discrete wavelet transform (DWT) domain of the original image using exact radial basis function neural networks (RBF). RBF will learn the characteristics of the image, and then watermark is embedded and extracted by the trained RBF. A watermark is added to the coefficients at the low frequency band of the DWT of an image and a watermark is embedded into the DWT domain using the trained RBF. The trained RBF also used in watermark extracting process. Experimental results show that the proposed method has good imperceptibility and high robustness to common image processing attacks.