Detecting Fraudulent Financial Information of a Company Using Hidden Markov Model

Ruicheng Yang,Ailing Zuo,Qing Shen 보안공학연구지원센터 2016 International Journal of Security and Its Applicat Vol.10 No.9

Using Hidden Markov Model (HMM), this paper detects some fraudulent financial information of a company. The research index MBSPM (Main Business Service Profit Margin) ratio of company is used to test the effectiveness of HMM. Due to the shortage of the fraudulent data, based on the MBSPM index data we generate the artificial fraudulent financial information data by Poisson process and Uniform distribution, that is, we use the Poisson process to simulate the arrival times of the fraudulent financial information and the Uniform distribution to simulate their fraudulent sizes. By embedding the artificial fraudulent financial information data into the non-fraudulent MBSPM data, we form the sample data series. Applying Henderson filter method, we derive the research sample data by getting rid of the sample data series trends. We do some experiments to test the validity of HMM for detecting the fraudulent financial information, and further make some comparisons with other detecting techniques: logistic regression and ANNs. The detected results show that the HMM approach can significantly improve the identification accuracy.

Preparation of Monodisperse Colloidal ZnO Nanoparticles and Their Optical Properties

Chong Yang,Limei Tang,Qingsong Li,Ailing Bai,Yanqiu Wang,Yingmin Yu 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2015 NANO Vol.10 No.5

Monodisperse colloidal zinc oxide (ZnO) nanospheres with a narrow size distribution were synthesized via a developed two-stage solution method. We controlled the size of the as-synthesized ZnO nanoparticles by varying the amount of ZnO/ethanol suspension added. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) revealed that the diameter of the as-synthesized ZnO nanoparticles was in the range of 60 – 140 nm with a polydispersity index less than 5%. On high-resolution TEM images, we clearly observed that the ZnO nanospheres were actually composed of tiny ZnO subunits, several nanometers in size. Powder X-ray diffraction and TEM-selected area electron diffraction analysis showed that the spheres consisted of polycrystalline nanoparticles. The size of the subunits, which was confirmed by ultraviolet (UV)-visible spectroscopy, increased as the amount of ZnO/ethanol suspension added was decreased. A UV emission at about 374 nm was observed, and this emission of ZnO nanoparticles is found to depend on particle size due to the confinement effect. A red emission at about 651 nm, which has been reported for undoped ZnO, appeared due to the excess oxygen on the particles from O – H or C=O groups. The intensity of the red emission increased as the relative oxygen content increased. The formation mechanism of such ZnO nanospheres was also considered.

Experimental investigation on noise emissions of an airfoil with non-flat plate trailing edge serrations

Eryun Chen,Yang Ma,Ailing Yang,Gaiping Zhao 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.7

This paper presents an experimental study on the aeroacoustic characteristics of an NACA 0018 with nonflat plate-type serrated trailing edge at Reynolds numbers of 500000 in an open-jet wind tunnel. The experimental results show that noise reduction can be achieved in the moderate frequency range for nonflat plate type triangular serrated trailing edges, but at the cost of producing narrowband tone noise. The level of the vortex shedding noise declines when serration length 2 h decreases. It is imperative that the vortex shedding tone noise be completely suppressed when a novel slanting root serrated trailing edge is adopted. Meanwhile, the ability of broadband noise reduction is maintained.

Numerical sensitivity study on nucleation bulk tension factor of non-equilibrium condensation model

Eryun Chen,Shiyin Fu,Ailing Yang,Shuxue Peng,Gaiping Zhao 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.2

The spontaneous condensation process of steam has obvious non-equilibrium characteristics, the accurate prediction of which is challenging. In this work, the nucleation bulk tension factor (NBTF) is used to modify the droplet surface tension for improving the accuracy in the calculation of the steam condensation flow. The non-equilibrium condensation processes in two nozzles are numerically simulated using a surface tension model with NBTF. The influence of NBTF on the simulation accuracy of the steam spontaneous condensation flow is analyzed. The correlation among the optimal value of NBTF, steam expansion rate and inlet parameters is emphatically studied. The obtained results show that the optimum value of NBTF is not sensitive to the change in the steam expansion rate under the same working conditions. It has no significant correlation with the total inlet temperature, but has a significant positive correlation with the total inlet pressure. Based on the numerical results, a cubic polynomial regression model between the optimal NBTF and total inlet pressure is obtained, the reliability of which is further verified by numerical calculation of a wet steam two-phase flow in the Bakhtar plane cascade. These results can provide a reference for determination of the optimum NBTF in wet steam condensation nucleation models.

Towards Unified Business Process Modeling and Verification for Role-based Resource-oriented Service Composition

Ming Gao,Lei Yang,Chunhua Zhang,Wen Guan,Ailing Li 보안공학연구지원센터 2016 International Journal of Hybrid Information Techno Vol.9 No.3

With the prevalence of ubiquitous computing, big data, and Internet of things in cloud computing environment, it’s important to consider both of collaboration, heterogeneity, isolation of multi-tenant applications and information security and privacy in service composition. Current methods need to be readdressed to cope with cross-organizational, multi-roles participated and knowledge-intensive service composition in an integrated way. Based on the modeling and verification theories of hierarchical colored petri-net, a resource-oriented collaborative workflow model, its resource control model and the joint modeling and verification method are proposed which present a unified solution bridging the gap between traditional structure-oriented workflow execution model and resource-oriented workflow domain model taking into account the underlying roles, tasks, resources and their association and coordination in design-time and runtime as well. In our approach, a business process is divided into three layers: the backbone top-level process, the task fulfillment sub-process and the task execution sub-process in order to reduce the complexity of model verification. In addition this paper gives in-depth discussions on the fine control of implicit parallel and multi-threaded process executions. Finally, the case studies show that the proposed methods are not only applicable to modeling and verification of traditional task-oriented workflows, but also suited for knowledge or data-intensive workflows which involve

Improved Thermal Conductivity and Mechanical Property of PTFE Reinforced with Al2O3

Min Chao,Changjuan Guo,Ailing Feng,Zhengyong Huang,Qingli Yang,Guanglei Wu 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.5

To achieve polymer-based composites for electronic packaging with high thermal conductivity, Al2O3 nanoplatelets were introduced into polytetrafluoroethylene (PTFE) matrix via a cold pressing and sintering method. The effect of mass content of the Al2O3 platelets on the morphology, mechanical properties, thermal conductivity and dielectric properties of the composites was investigated. The results revealed that the Al2O3/PTFE nanocomposites exhibited higher thermal conductivities, better thermal stabilities, enhanced mechanical properties with considerable dielectric properties. The largest thermal conductivity of the Al2O3/PTFE nanocomposites filled with 25 wt.% Al2O3 platelets was 0.461 W m -1 K -1, increased by 85% compared with that of pure PTFE. The improved thermal conductivity of Al2O3/PTFE can be attributed to the formation of effective thermal conductance network within the PTFE matrix due to the inter-connectivity of Al2O3 platelets.

Design and Prediction of Three Dimensional Flows in a Low Speed Highly Loaded Axial Flow Fan

Liu, Xuejiao,Chen, Liu,Dai, Ren,Yang, Ailing Korean Society for Fluid machinery 2013 International journal of fluid machinery and syste Vol.6 No.2

This paper describes the design to increase the blade loading factor of a low speed axial flow fan from normal 0.42 to highly loaded 0.55. A three-dimensional viscous solver is used to model the flows in the highly-loaded and normal loaded stages over its operation range. At the design point operation the static pressure rise can be increased by 20 percent with a deficit of efficiency by 0.3 percent. In the highly loaded fan stage, the rotor hub flow stalls, and separation vortex extends over the rotor hub region. The backflow, which occurs along the stator hub-suction surface, changes the exit flow from the prescribed axial direction. Results in this paper confirm that the limitation of the two dimensional diffusion does not affect primarily on the fan's performance. Highly loaded fan may have actually better performance than its two dimensional design. Three dimensional designing approaches may lead to better highly loaded fan with controlled rotor hub stall.

Design and Prediction of Three Dimensional Flows in a Low Speed Highly Loaded Axial Flow Fan

Xuejiao Liu,Liu Chen,Ren Dai,Ailing Yang 한국유체기계학회 2013 International journal of fluid machinery and syste Vol.6 No.2

This paper describes the design to increase the blade loading factor of a low speed axial flow fan from normal 0.42 to highly loaded 0.55. A three-dimensional viscous solver is used to model the flows in the highly-loaded and normal loaded stages over its operation range. At the design point operation the static pressure rise can be increased by 20 percent with a deficit of efficiency by 0.3 percent. In the highly loaded fan stage, the rotor hub flow stalls, and separation vortex extends over the rotor hub region. The backflow, which occurs along the stator hub-suction surface, changes the exit flow from the prescribed axial direction. Results in this paper confirm that the limitation of the two dimensional diffusion does not affect primarily on the fan's performance. Highly loaded fan may have actually better performance than its two dimensional design. Three dimensional designing approaches may lead to better highly loaded fan with controlled rotor hub stall.

Numerical investigation on vibration and noise induced by unsteady flow in an axial-flow pump

Eryun Chen,Zuiling Ma,Gaiping Zhao,Guoping Li,Ailing Yang,Guofang Nan 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.12

Full-scale structural vibration and noise induced by flow in an axial-flow pump was simulated by a hybrid numerical method. An unsteady flow field was solved by a large eddy simulation-based computational fluid dynamics commercial code, Fluent. An experimental validation on pressure fluctuations was performed to impose an appropriate vibration exciting source. The consistency between the computed results and experimental tests were interesting. The modes of the axial-flow pump were computed by the finite element method. After that, the pump vibration and sound field were solved using a coupled vibro-acoustic model. The numerical results indicated that the the blade-passing frequency was the dominant frequency of the vibration acceleration of the pump. This result was consistent with frequency spectral characteristics of unsteady pressure fluctuation. Finally, comparisons of the vibration acceleration between the computed results and the experimental test were conducted. These comparisons validated the computed results. This study shows that using the hybrid numerical method to evaluate the flow-induced vibration and noise generated in an axial-flow pump is feasible.