bluuebunny/crossref_metadata_2025 huggingface dataset:
Forecasting Model of Humidity in Chinese Solar Greenhouse in the North Drought Cold Area and Experiment in Winter
Authors: Bi Yu Ge , Ma Shuo Shi
Published: July 2011

Based on the research results of light environment and thermal environment model and the principle of mass balance, the dynamic forecasting model of Humidity in Chinese solar greenhouse in the north drought cold area was established. The influenced factors correlative with water vapor change such as crop transpiration, soil evaporation, covered material condensation and natural or winded of closed situation ventilation were included in the model. To validate the correctness of the model, an experiment was carried out in the Chinese solar greenhouse in the Inner Mongolia agriculture science and technology park. The results showed that the inner relative humidity forecasted agreed well with the measured data in the north drought cold area in winter, and the relative error is less than 10%.
Design of the Glass Matching-Material System Based on the Fuzzy-PID Control
Authors: Liu Yan Chang , Zheng Wei , Zhang Jia , Ma Yu Kun
Published: July 2011

In order to resolve the problems of low precision and bad real-time of traditional control methods of matching-material system, this paper has proposed the coordination control algorithm. This paper has designed a Glass matching-material system based on the Fuzzy-PID control by using of combining the traditional PID and the Fuzzy control algorithm. The system uses expert system and adjusts automatically the control parameters online learning to realize control of the best combination of precision and speed. The running result of the system has proved the feasibility and validity of the Fuzzy-PID coordination control.
The Design of Curriculum Website
Authors: Ou Qi Zhong , Huang Xing Yun
Published: July 2011

Curriculum website is an effective form to realize educational informatization. How to design a good curriculum website? This paper introduces its basic structure from the aspects of learning module, resource module, communication module and management module, as well as its teaching design from the aspects of teaching objective, design concept and method, the hierarchy of knowledge, learning evaluation, and also the technical design from the aspects of website navigation, website security, and website scalability.
Application of Optimized DDS Based on FPGA in the Two-Phase Flow
Authors: Li Lin , Shi Hai Tao , Wang Xin Gang
Published: July 2011

Flow regime recognition of two-phase flow is of great importance in industrial process. This paper describes the role of the field-programmable gate array (FPGA) hardware, in the implementation of electrical resistance tomography (ERT), which is used to analyze gas/liquid two phase flows. Firstly, a brief introduction and some theoretical analysis are made about the basic principles of Direct Digital Synthesizer (DDS). Then a signal source for ERT system based on DDS and FPGA is designed and a kind of compression ROM is realized. The whole system has been simulated in the Quartus II 7.2 simulation environment and successfully downloaded to the chip of the Cyclone II EP2C5F256C6. The operating results and the theoretical results show that the proposed method can greatly improve the developing efficiency, save plenty of the system resources and improve the reliability and flexibility.
Research on the Cyber Terrorist Attacks and its Impacts on Information Infrastructure Security
Authors: Yao Dong Liang , Liu Xiao Qin
Published: July 2011

With technology advances, the interdependence of various infrastructures has increased, which enhances their vulnerabilities. The national information infrastructure security concerns the nation's stability and economic security. Risk assessment methodology was introduced into the safeguard of the information infrastructure, which is prone to terrorist attack. Through the analysis of terrorists’ behaviors and its characteristics, the four steps of risk management were studied in detail using many factual examples. The macroscopic and microscopic countermeasures were developed lately, which attribute to adopting counteractions to reduce the vulnerability and relieve the risk in the modern society caused by terrorist attack.
The SIFT Image Feature Matching Based on the Plural Differential
Authors: Zhou Shang Bo , Li Yong
Published: July 2011

For the existing methods of image registration based on feature, a new method of image registration based on plural differential is proposed with the theory of plural differential. The proposed method uses plural differential to enhance the texture feature of the digital image first, and then uses SIFT to extract the keypoints, at last uses the RANSAC algorithm to get the correct number of matching keypoints.
Solar Cells System Based on Light Positioning
Authors: Min Yu Tang , Luo Xiao Ling , Huang Ben Xiong
Published: July 2011

The system use surveillance camera and image rendering developed a new solar positioning system. The system’s position detection method is to use surveillance cameras captured source image, and then use rendering method to determine the location of the light source to adjust the orientation of solar cells to improve the utilization of the battery. We use existing camera filming the scene of the source image, and then the light source position will be determined. Through the back of our tracking software processing, adjusting the orientation of solar collectors, will allow maximum utilization of solar energy and provide solar tracking areas a new and reliable detection methods. This article focuses on algorithm design of the source tracking software. This article uses the prior knowledge of three-dimensional objects in the photo image to model. Priori knowledge can help us to determine all the parameter except light source location, we full traversal all the possible light source position space. After getting the rendering image, rendered image and source image will be compared through the evaluation function, thus we will get the best source location parameters.
An Approach on Bus Temporal Character Calculation Based on Real-Time Information Processing
Authors: Chen Shao Hui , Chen Yan Yan
Published: July 2011

The article studies the methods of processing bus real-time information (GPS data) and calculating the temporal indexes for decision making in bus dispatching. The kalman filter algorithm is used to predict the bus arrival time. The result shows the prediction error is within 1.3 minutes and the precision is 71% by calculating the real-time information of Beijing bus intelligent transportation system.
Speeding up Data Distribution of BitTorrent-Like P2P Systems
Authors: Wu Ji Qing , Peng Yu Xing
Published: July 2011

Data distribution is the basic behavior of P2P applications ( le sharing and stream- ing service) and it is a key element a ecting the performance of P2P systems. However, there are few research works that focus on data distribution of P2P applications from the view of whole system. In this paper we study the data distribution in P2P applications in terms of de- creasing the system distribution load. We de ne the distribution load of P2P systems formally and analyze how to decrease the system load quickly by means of mathematical analysis. More- over, we give a feasible fast distribution algorithm according to our theoretic conclusion. The experimental results show that our algorithm has signi cant improvement on data distribution speed and load balance.
Simulation of No-Load Voltage of Single Phase Synchronous Generator Based on ANSYS
Authors: Yang Jing , Wang Wei Jun , Zuo Yong Gang , Feng Ping , Mao Long Bo
Published: July 2011

The theory and method of analyzing the no-load magnetic field of single phase synchronous generator(SPSG) is presented in this article, and the no-load voltage of SPSG is simulated based on ANSYS program. The no-load voltage simulation results of a SPSG resemble its test results, which prove the simulation method in this article is correct and effective. The simulation results can provide theoretical bases and method for engineers in optimizing the design parameters to improve the power supply quality of SPSG.
Sensitivity Analysis of a Bioinspired Refractive Index Based Gas Sensor
Authors: Gao Yang , Xia Qi , Liao Guang Lan , Shi Tie Lin
Published: July 2011

Nano-structures on the wing of Morpho butterflies generate bright blue color, and this color is sensitive to ambient gas, or more specifically, the refractive index of ambient gas. It was found that even slight change of the refractive index can lead to obvious change of the color. Such phenomenon has caught much attention and was employed as a sensing principle for detecting gas. In the present study, a typical nano-structure on the wing of Morpho butterflies is mimicked and simplified for constructing a refractive index based gas sensor. Moreover, partial derivative of the optical reflection efficiency with respect to the refractive index of ambient gas, i.e., sensitivity of the sensor, is utilized based on the rigorous coupled-wave analysis (RCWA) method. Finally, the effects of the nano-structure’s shape on the partial derivative are analyzed. The results can be applied to the design of the bioinspired refractive index based gas sensor.
ACO Algorithm for Scheduling Complex Unrelated Parallel Machine
Authors: Liu Guo Bao , Zhu Qiong , Zhang Jie
Published: July 2011

This Paper Addresses an Unrelated Parallel Machine Scheduling Problem with Job Sequence-Dependent Setup Times. Jobs Have Precedence Constraints. the Objective Is to Minimize the Makespan. the Problem Has Applications in Industries such as TFT-LCD, Textile Manufactures. the Problem Is NP-Hard in Strong Sense. Therefore, an Ant Colony Optimization (ACO) Algorithm Is Introduced to Solve this NP-Hard Problem. the Proposed ACO Tackles the Special Structure of the Problem. its Performance Is Evaluated by Comparing its Solutions with Cplex Method. the Results Show that ACO Outperformed the Cplex Method.
Numerical Simulation of a Semi-Confined Slot Turbulent Impinging Jet
Authors: Wang Ming Bo , Wang Rui He , Liu Xian Yong
Published: July 2011

A Realizable k-ε turbulence model in conjunction with a standard wall function has been applied to the prediction of a fully-developed two-dimensional jet impinging within a semi-confined space. A single geometry with a Reynolds number of 10,000 and a nozzle –to-plate spacing of eight diameters has been considered at different inlet boundary conditions. The numerical results, including the time-averaged velocities and the turbulent intensity, have been compared with the experimental data reported by Yoshida (ref 5). It is found that the trends in the axial velocity, the radial velocity and the turbulent intensity are fairly predicted. The fully-developed boundary condition is generally better than the constant velocity boundary condition. The differences between the numerical and experimental results can be attributed to the turbulence model and the treatment of the low Reynolds number zone near the wall.
Magnetic Properties of Bulk Zn0.95-XMnXFe0.05O2 Prepared by Sol-Gel Method and Subsequent Hot Pressing
Authors: Lin Wen Song , Wen C. H. , He Liang
Published: July 2011

Mn, Fe doped ZnO powders (Zn0.95-xMnxFe0.05O2, x≤0.05) were synthesized by an ameliorated sol-gel method, using Zn(CH3COO)2, Mn(CH3COO)2and FeCl2as the raw materials, with the addition of vitamin C as a kind of chemical reducer. The resulting powder was subsequently compacted under pressure of 10 MPa at the temperature of 873K in vacuum. The crystal structure and magnetic properties of Zn0.95-xMnxFe0.05O2powder and bulk samples have been investigated by X-ray diffraction (XRD) and vibrating sample magnetometer (VSM). X-ray photoelectron spectroscopy (XPS) was used to study chemical valence of manganese, iron and zinc in the samples. The x-ray diffraction (XRD) results showed that Zn0.95-xMnxFe0.05O (x≤0.05) samples were single phase with the ZnO-like wurtzite structure. No secondary phase was found in the XRD spectrum. X-ray photoelectron spectroscopy (XPS) showed that Fe and Mn existed in Zn0.95-xMnxFe0.05O2samples in Fe2+and Mn2+states. The results of VSM experiment proved the room temperature ferromagnetic properties (RTFP) of Mn, Fe co-doped ZnO samples.
Design and Simulation of Multi-Function Self-Help Wheelchair
Authors: Zhou Yu Lan , Li Li , Ma Yong Jun , Wu Yong Chao
Published: July 2011

Multi-function self-help climbing stair wheelchair, which based on transforming the traditional wheelchair, achieves the function of climbing stairs by adding some simple structure. This article will introduce the wheelchair structure and principle and research and analysis the feasibility analysis.
The Application of Data Warehouse in Decision Support System
Authors: Yang Xiao Hua
Published: July 2011

Decision support systems provide the field of query optimization with increasing challenges in the traditional questions of selectivity estimation that can exploit transformations without exploding search space. The aims of this paper are to understand what the data warehouse and protect the sensitive information stored elsewhere in data warehouse. In the system, management level of system can review all records of historical data for monthly or yearly as user desired item for each dimension. This system is developed to easy access for frequently needed data, to improve end-user respond time. The paper results in accumulation of growing amounts of data in operational databases. The system can help to retrieve complex query analysis report. In this paper, we analyze personnel information by using Data Warehouse and OLAP tools.
Design of Aircraft Electrical Load Management Center
Authors: Wu Jian Jun , Wan Wei , Wu Peng
Published: July 2011

Aircraft Electrical Load Management Center, an important part of the aircraft power supply system, solves the automatic management of aircraft load via a multi-channel transmission bus and a solid-state power controller. Using micro-computer technology, instead of manual operation, for automatic control and management of the load has improved the existing method of distribution and load management, which has enhanced performance of aircraft and its maintenance of power system. This paper studies the overall structure and composition principle of ELMC and details ELMC’s functions of each component modules and the implementation of hardware and software. System test results show that the automatic load management techniques greatly improve the aircraft power system reliability and maintainability.
Practical Research into the Degree of Influence by the Intrinsic Motivation and the Extrinsic Motivation
Authors: Xie Qing Song
Published: July 2011

Language learners are not machines to be programmed but people with likes and dislikes, weaknesses and prejudices. This paper intends to discuss the affective factor --motivation of language learners. The author surveys motivation with the focus on the classification of intrinsic motivation and extrinsic motivation and compares their different influences on senior high school students. Anyway, the author aims to provide some suggestions and first-hand datum for high school English teaching.
Development of the Open Architecture Platform for Controller
Authors: Xi Jun Mei , Liao Gao Hua
Published: July 2011

At present，the open arehitecture controller and the field bus for motion control is a hotspot at home and abroad in the field of numerieal control system.This paper analyses the advantage of the typieal open arehitecture controller and improves.The open movement contro1 Platform based on BUS,which uses the open numrerieal control arehiteehire, that is，in order to control the system intelligently, We use a signal wire or optical fibre which connects all the drivers and the I/O port to transmit signals. In the system，all the control is operated by the up-pc machine，and the intelligent control nod is only used for communicating and translating the instruction.The control system uses Visual C# to empolder the up-pc software, and uses C to empolder the intelligent control interface. Experiments show that the system with the velocity error of less than 5%, the transition time of less than 0.1s, position error of less than 1mm. It can achieve not only the customization of the human-machine interface, and the parameterization of the real-time control parts, but also the exact travel path, the fast response, high accuracy positioning and other performance.
Research about Air Level Posture Sensor
Authors: Li Bai Hua , Piao Lin Hua , Ji Ming Ming
Published: July 2011

Sensitive principle of air level posture sensor is introduced and test to the actual manufacture's sensor is carried on. The test result indicates that the temperature’s influence to the sensitivity is suppressed basically; the operating temperature scope expands from the normal temperature to 30°C; the resolution surpasses over 0.1°; misalignment of air level posture in full scale scope is smaller than 1%，measuring range the angle of tilt may achieve to 20°.
Research on Evaluation Method of an Excellent Teaching Team
Authors: Yu Hai Zhen , Zhong Sheng
Published: July 2011

This paper, with the concern in view, has presented here a multiobjective optimiza- tion model. By generalizing parameters from the construction process of a team at di_erent stages and from di_erent angles, and by comparing them to the set optimization goal, this model aims to evaluate the outcome of the construction of a team in an accurate and fair way. And by steering clear to the greatest extent of the inuence of the individual or subjective factors, the model also strives to derive a better result from the equal input in the construction of an excellent teaching team.
Training the Innovation Ability of the College Students: Element, Mode and Experience
Authors: Qiao Hai Shu , Li Yuan Hang , Zhang Teng
Published: July 2011

The key to the cultivation of elites in the new era lies in the training of the innovation ability of the college students. Based on elements constitution, mode examination and experience summary, this paper studied the status of the college students’ innovation ability cultivation in China in both theory and realistic. Therefore, the paper managed to lead the cultivation of the innovation ability of college students to a more scientific and efficient development.
Incorporate Syntactic Information for Short Text Classification
Authors: Duan Rui Xue , Wang Xiao Jie , Li Wen Feng
Published: July 2011

As the volume of online short text documents grow tremendously on the Internet, it is much more urgent to solve the task of organizing the short texts well. However, the traditional feature selection methods cannot suitable for the short text. In this paper, we proposed a method to incorporate syntactic information for the short text. It emphasizes the feature which has more dependency relations with other words. The classifier SVM and machine learning environment Weka are involved in our experiments. The experiment results show that incorporate syntactic information in the short text, we can get more powerful features than traditional feature selection methods, such as DF, CHI. The precision of short text classification improved from 86.2% to 90.8%.
The Deep Meaning of Enterprise Culture Construction
Authors: Liu Xiao Tie
Published: July 2011

Since 1990s, enterprise management has gradually become from experience management and scientific management to cultural management, the enterprise cultural construction transformed an important way to improve enterprise operating performance. Its profound meaning is: to condense and activate human capital, cultivate core competence, enhance the brand image, enhance the efficiency of management system.
MBO of Chinese State-Owned SMEs: Fate and the Way Out
Authors: Xie Pin
Published: July 2011

While approval for MBO of large-scale enterprises has been suspended, MBO of the state-owned SMEs has set off a new round of MBO wave. Chinese primary state-owned and collective SMEs unify management rights and ownership through the implementation of MBO, with property rights being clear to the natural person of the management level and the reform being of certain spontaneity. However, the state-owned SMEs have such widespread problems as unperfected law system, narrow financing channels and inadequate information disclosure in the process of implementation. Based on the status, problems and cause analysis of implementation of MBO in Chines state-owned SMEs at this stage and aiming at the law, financing, pricing, information disclosure and other issues within, this paper puts forward countermeasures and suggestions related to further improving MBO of Chinese SMEs.
Intervention on the Children Simple Obesity by Sports
Authors: An Xiao Qian
Published: July 2011

Positions and roles of sports in treatment of children simple obesity are expatriated .Basic contents of exercise prescription are discussed from items,intensity and time of sports.In order toprevent and to cure the obesity effectively,people should keep on physical exercise regularly.
The Study on Guanxi Structure of Colleagues in the Background of Chinese Culture and its Influence on Individual Job Performance
Authors: Li Min
Published: July 2011

Based on the study on the literature, combined with interviews, this paper theoretically proposed four dimensions of the guanxi structure among colleagues in the background of Chinese culture (emotional, instrumental, obligations and face.) Through the data of 611 valid questionnaires from enterprises with different sizes and natures, the models of guanxi structure between colleagues are obtained ,which have Chinese cultural characteristics.Through regression analysis, we find that the guanxi between colleagues has a positive influence on individual job performance, but the guanxi does a different direction of the impact in sub-domains of job performance from the sub-domains of coworker guanxi, and the influences are also different.
Peak and Crisis of Modernity - Analysis on Stauss Modernity Third Wave
Authors: Li Shi Guang
Published: July 2011

Strauss believed that modernity has peaked after three waves. The third modernity wave started from Nietzsche and peaked at Heidegger. As the top of modernity, there are four characteristics of the third wave: historical concept of Radical Historicism, existential experience of pessimism, ethical ideas of Vitalism, Fascism ethical inception. They have composed of the deepest crisis of modernity.
Large Eddy Simulations of Unsteady Wakes behind Riser in Offshore Deep Water
Authors: Zhu Hong Jun , Ou Zhi Peng , Lin Yuan Hua , Hu Fang Fang
Published: July 2011

Riser vortex-induced vibration (VIV) has been the outstanding problem affecting the normal safe operation in offshore oil exploitation. In this paper, based on computational fluid dynamics, a three-dimensional large eddy simulation (LES) numerical model was used to calculate the flow fields of unsteady flow around marine riser with different approaching flow velocities. Then streamlines, velocity and vorticity contours, drag and lift coefficients in different conditions were obtained. Simulation results indicate that the flow properties in different depth display obvious difference, which present complex three dimensional characteristics with interacting. It is thus clear that flow around marine riser can not be regarded as plane potential flow simply. The results also show that with larger approaching flow velocity, lift coefficient amplitude is bigger and frequency is higher, which is easier to result in vibration. Our approach may provide some references for safe design and engineering practice of VIV controlling of marine riser.
The Improvement of Hybrid Particle Swarm Algorithm and its Application
Authors: Zou Shu Rong , Ding Peng Xin , Zhang Hong Wei
Published: July 2011

Hybrid multi-objective particle swarm algorithm is applied to vehicle routing problem and achieved good results, this paper based on the previous work, dynamic inertia weight is added to the particle swarm algorithm with intelligence factors, it improved the global search ability and the capacity of local convergence of the particle swarm algorithm; and the idea of immunity is introduced in the algorithm ,which makes the hybrid multi-objective particle swarm algorithm can effectively discard the repeated solutions in solving vehicle routing problems, this operation can improve the efficiency of the algorithm, and obtain better results under the same conditions.
Noise Speech Recognition Based on Compressive Sensing
Authors: Zhao Zhi Peng , Cen Yi Gang , Chen Xiao Fang
Published: July 2011

In this paper, we proposed a new noise speech recognition method based on the compressive sensing theory. Through compressive sensing, our method increases the anti-noise ability of speech recognition system greatly, which leads to the improvement of the recognition accuracy. According to the experiments, our proposed method achieved better recognition performance compared with the traditional isolated word recognition method based on DTW algorithm.
Efficient Ontology Integration Model for Better Inference in Context Aware Computing
Authors: Yang Soo Mi
Published: July 2011

In this paper, we describe efficient ontology integration model for better context inference based on distributed ontology framework. Context aware computing with inference based on ontology is widely used in distributed surveillance environment. In such a distributed surveillance environment, surveillance devices such as smart cameras may carry heterogeneous video data with different transmission ranges, latency, and formats. However even smart devices, they generally have small memory and power which can manage only part of ontology data. In our efficient ontology integration model, each of agents built in such devices get services not only from a region server, but also peer servers. For such a collaborative network, an effective cache framework that can handle heterogeneous devices is required for the efficient ontology integration. In this paper, we propose a efficient ontology integration model which is adaptive to the actual device demands and that of its neighbors. Our scheme shows the efficiency of model resulted in better context inference.
Computational Fracture Modelling in Bioceramic Structures
Authors: Li Wei , Rungsiyakull Chaiy , Zhang Zhong Pu , Zhou Shi Wei , Swain Michael V. , Ichim Ionut , Li Qing
Published: July 2011

Bioceramics have rapidly emerged as one of major biomaterials in modern biomedical applications because of its outstanding biocompatibility. However, one drawback is its low tensile strength and fracture toughness due to brittleness and inherent microstructural defects, which to a certain extent prevents the ceramics from fully replacing metals used as load-bearing prostheses. This paper aims to model the crack initiation and propagation in ceramic fixed partial denture, namely dental bridge, by using two recently developed methods namely continuum-to-discrete element method (CDEM) in ELFEN and extended finite element methods (XFEM) in ABAQUS. Unlike most existing studies that typically required prescriptions of initial cracks, these two new approaches will model crack initiation and propagation automatically. They are applied to a typical prosthodontic example, thereby demonstrating their applicability and effectiveness in biomedical applications.
Design and Simulation Analysis of Tamper System for Multifunction-Paver
Authors: Wu Guo Yang
Published: July 2011

In this article, the tamper system of multifunction- paver has been simulated by AMESim, and the simulation model of the tamper system of multifunction- paver has been established. The simulation results show that the hydraulic impact of the system will be decreased and the response speed of the system will be improved, when accumulator and PID controller are equipped. Simultaneously, the stability of vibrated system will go down with the increase of vibration frequency. When vibration frequency is over 20 HZ, the performance of system will go bad, and the vibration of system will be significantly enhanced.
First-Principles Calculations of Elastic and Thermodynamic Properties of Cubic CdTe
Authors: Yu Ben Hai , Chen Dong
Published: July 2011

the equilibrium lattice constants, elastic and thermodynamic properties of cubic CdTe are systemically investigated at high temperature using the plane-wave pseudopotential method as well as the quasi-harmonic Debye model. The bulk modulus of CdTe are calculated as a function of temperature up to 1000K, the relationship between bulk modulusBand pressure is also obtained. The results gained from this model will provide overall predictions accurately for the temperature and pressure dependence of various quantities such as the bulk modulus, the heat capacity and the thermal expansion coefficient. More over, the dependences between Debye temperature and temperature are also successfully obtained. Our results are compared with the experimental data and discussed in light of previous works.
A Data Allocation Strategy Algorithm for Large Databases Based on Genetic Algorithm
Authors: Li Xiao Feng , Tang Yuan Xin , Gong Cui Cui
Published: July 2011

The distributed database system is the product that the database system combines with the computer network system. The data distribution problem has great influence on distributed database application system improvement, data availability, the efficiency and reliability of the distributed database. The allocation strategies in this paper have used some excellent properties in genetic algorithms, including higher parallelism and robustness, the realization of standard way, and to maintain good balance between the depth prior search and breadth prior search, etc, so the allocation strategies in this article's have high execution efficiency, with stronger ability in seeking the best global solution and easy to realize.
Based on Pro/E on the Design and Simulation of Bionic Dragonfly Flapping Wing Aircraft
Authors: Zhou Yu Lan , Wang Kun , Chai Jing Ping
Published: July 2011

In order to design an efficient, reliable, light weight, flapping wing mechanism,Improve the flight performance of the micro air vehicle and expand its application areas,this paper is concerned on the design and simulation of bionic dragonfly flapping wing aircraft .An mechanism design to simulate the movement of dragonfly wings isr presented in this paper.Then, simulation and analysis are made based on Pro/E.
An Intrusion Detection Based on Markov Model
Authors: Li Hai Sheng
Published: July 2011

This paper presents an Intrusion detection technique through anomaly-detection, and proposes Modeling algorithm using training data and anomaly detection model. In this technique, a Markov-chain model is founded based on the characteristic pattern, which is a subsequence of system calls if this sequence satisfies the certain support degree. Experiments show that the method with high detection rate and low false alarm rate is valuable to intrusion detection.
A New Methodology for the Reliability Based Particle Swarm Optimization with Simulated Annealing
Authors: Elhami Norelislam , Ellaia Rachid , Itmi Mhamed
Published: July 2011

This paper presents a new methodology for the Reliability Based Particle Swarm Optimization with Simulated Annealing. The reliability analysis procedure couple traditional and modified first and second order reliability methods, in rectangular plates modelled by an Assumed Modes approach. Both reliability methods are applicable to the implicit limit state functions through numerical models, like those based on the Assumed Mode Method. For traditional reliability approaches, the algorithms FORM and SORM use a Newton-Raphson procedure for estimate design point. In modified approaches, the algorithms are based on heuristic optimization methods such as Particle Swarm Optimization and Simulated Annealing Optimization. Numerical applications in static, dynamic and stability problems are used to illustrate the applicability and effectiveness of proposed methodology. These examples consist in a rectangular plates subjected to in-plane external loads, material and geometrical parameters which are considered as random variables. The results show that the predicted reliability levels are accurate to evaluate simultaneously various implicit limit state functions with respect to static, dynamic and stability criterions.
Modeling a Discrete Interaction Jets/Wall Flow. Effect of Curvature
Authors: Berkache Amar , Dizene Rabah
Published: July 2011

A numerical simulation is used to evaluate the curvature effects of the wall on features of the interaction between discrete jets and cross flow, and therefore on the efficiency of the cooling. The injection is realized in a turbulent limit layer through only one row of openings. Our study was especially based on the SST model that is efficient in the capture of the phenomena near and in the wall. Three turbulence models are used; the k-, the RSM and the SST on a flat plate crossed by throw in order to identify which of these models are more capable to capture the near wall interaction phenomena. Discrete jets are arranged across a surface exposed to a wall boundary layer of parallel compressible stream, as occurs in certain discrete-hole cooling systems for turbine blades. Comparisons of the results of this study are presented in the case of a flat plate crossed by throw inclined of 45° with a rate injection Ra=0.6. These results compared to experimental data proved the aptitude of the SST model, in relation to the other models in this case of problems. Applied for a NACA0012 profile, this model (SST) revealed us the distinct difference of features of the interaction in relation to the flat plate.
Residual Strength Optimisation of a Vent Hole in an Aircraft Component Using a Heuristic Method
Authors: Das Raj , Jones Rhys
Published: July 2011

The paper presents application of damage tolerance optimisation principles to the design of industrial components. It is illustrated via design optimisation of a Fuel Flow Vent Hole (FFVH) located in the Wing Pivot Fitting (WPF) of an F-111 aircraft. The aim is to determine the shape of the cutout that will maximise its residual strength under the operating loading conditions. Damage tolerance shape optimisation is performed using a heuristic optimisation method known as the ‘Biological algorithm’. The maximum stress intensity factor (SIF) for all of the cracks around the boundary of the optimal cutout is found to be significantly lower compared to that of the initial shape. This shows that an improved residual (fracture) strength is achieved for the optimal designs. The variability in SIF around the cutout boundary is reduced, thereby making the shape more evenly fracture critical. The shapes of the residual strength optimal vent holes are found to depend on the initial crack sizes. It is also shown that a damage tolerance optimisation additionally produces a lighter WPF component design, which is highly desirable for aerospace industries.
Modelling Fatigue Crack Growth near an Open Hole under Spectrum Loading Using a New Method for Elastic-Plastic Stress Calculation
Authors: Wallbrink Chris , Hu Wei Ping
Published: July 2011

To date the analysis of fatigue crack growth from an open hole subjected to contained cyclic plastic deformation is problematic due to considerable computational effort involved. This paper presents the integration of a new efficient method for calculating the elastic-plastic notch stress field under cyclic loading into a crack growth analysis tool. The anticipated crack path is defined along a line emanating from an open hole, and the line is discretized into a series of elements on which the elastic-plastic stress distribution is solved for the uncracked body. This solution is then used in conjunction with a weight function approach to determine the stress intensity factors used in the crack growth analysis. This technique has been incorporated into a Defence Science and Technology Organisation proprietary crack growth analysis tool based on plasticity-induced crack closure. Results are presented for cases involving service load spectra from F/A-18 and F-111 aircraft and are compared to those obtained from a commonly used crack growth code that does not account for the effect of contained notch plasticity. It is hoped that this generic approach will lead to improved predictions for crack growth in plasticity-affected zones.
Processing of Layered Hydroxyapatite Ceramic Composites
Authors: Sultana Rumana , Yang Jing Zhou , Hu Xiao Zhi
Published: July 2011

Layered hydroxyapatite (HA) based ceramic composites consisting of a strong ceramic composite core, 3 mol% yttrium stabilized zirconia (3Y-TZP) with 30 or 40 vol% HA, and a HA-rich porous coating were fabricated using a coating deposition and co-sintering process in the present study. The aim is to develop HA-based bio-ceramic composites that retain the bio-compatibility of HA and the preferred scaffold structure, but have much improved structural properties required for implants. Two different coating techniques, sol-gel derive HA coating and HA solution coating, have been used to deposit the HA coating on the strong HA-containing 3Y-TZP core, which has been pre-sintered at 900°C and has a green-machined surface finish. The upper limit for the final sintering of the layered ceramic composites is set at 1,350°C based on the individual sintering properties of HA and 3Y-TZP. SEM observations have been conducted on the coating surface, sectioned surface of coating and substrate/core to characterize the microstructures of coating and substrate and their interface. Preliminary mechanical tests and XRD tests are also performed to characterise the structural properties at different temperatures.
Wear Evaluation of SiCp Reinforced Al Matrix Composites Coatings
Authors: Kim Kyun Tak , Kim Yeong Sik
Published: July 2011

Thermal spray technology provides wear-resistant coating on the surface of mechanical components. In this study, wear characteristics of SiCp reinforced Al matrix composite coatings were evaluated. SiCp reinforced Al matrix composite coatings were fabricated using the mixed powders which have different fraction of the SiC reinforcement, 0, 20, 40 and 60 vol% on Al 6061 substrate by thermal spray process. Dry sliding wear tests were performed on these coatings using varied sliding speeds and applied loads. Wear behavior of these Al-based composite coatings were investigated using scanning electron microscope(SEM), energy dispersive X-ray spectroscopy(EDX) and X-ray diffraction(XRD). The composites coatings reinforced with 40 vol% of SiC particles showed the most excellent wear resistance. Although the wear rate increased according to the increase in the applied load, it decreased according to the increase in the sliding speed. The major wear behavior of the SiCp reinforced Al matrix composite coatings is transferred from the adhesive wear to the abrasive wear according to the increase in the sliding speed and the applied load. These results were significantly influenced by the formation of mechanical mixed layer(MML).
Mechanical Behaviour of Titanium, Ti-6Al-4V (wt %) Alloy and Ti-47Al-2Cr (at %) Alloy Produced Using Powder Compact Forging
Authors: Nadakuduru V.N. , Zhang De Liang , Raynova Stella , Cao Peng , Gabbitas Brian
Published: July 2011

Powder compact forging was used to produce bulk consolidated titanium and Ti-6Al-4V (wt %) and Ti-47Al-2Cr (at%) alloy disks from hydrogenated and dehydrogenated (HDH) and gas atomised powders (GA) powders (in the case of titanium and Ti-6Al-4V) and a mechanically milled powder (in the case of Ti-47Al-2Cr alloy). The bulk titanium and Ti-6Al-4V (wt %) alloy have been produced by forging of the powder compacts. The Ti-47Al-2Cr (at %) alloy was produced using canned powder compact forging of a Ti/Al/Cr composite powder. The purpose of the present study is to investigate the deformation and fracture behaviour of the bulk consolidated as-forged materials, by conducting tensile testing at room temperature (RT) and examination of the fractured specimens which had near-α, α + β and  phase structures, respectively. It was found that as-forged bulk titanium disk produced using HDH powder showed a yield point with a yield strength of ~700 MPa and with a considerable amount of ductility. While the as-forged Ti-6Al-4V (wt %) alloy produced using HDH powder, fractured prematurely without any yielding. On the other hand yielding was observed in the as-forged Ti-6Al-4V (wt %) alloy produced using GA powder, showing a yield strength of ~970 MPa and a considerable amount of plastic strain to fracture. The bulk consolidated Ti-47Al-2Cr (at %) alloy also fractured prematurely with fracture strength of ~125 MPa. The mechanical behaviour of the as-forged bulk materials was found to be dependent on several factors such as initial powders used, green density of the powder compact, forging parameters used during forging. It was expected that the entrapped gas in green compacts, absorbed oxygen, porosity and inter-particle bonding play an important role on the quality of the as-forged material, which in turn affected the mechanical behaviour of the bulk material.
Tensile Properties and Fracture Behaviour of Induction Sintered Ti and Ti-6Al-4V (wt %) Powder Compacts
Authors: Raynova Stella , Zhang De Liang , Polo D. , Gonthier L. , Egea W. , Nadakuduru V.N.
Published: July 2011

Induction heating of powder compacts could be a very effective method for metal powder consolidation to get the final product or as an intermediate consolidation step to produce feedstock for metal powder forging or extrusion. Our study has proven that only a few minutes of induction heating, of Ti and Ti-6Al-4V (wt %) powder compacts, increases their density dramatically and causes a significant sintering effect, as evidenced by the formation of interparticle diffusion bonding and reflected by the tensile properties of the induction sintered powder compacts. This paper presents and discusses the results of a study on the tensile properties and fracture behaviour of the Ti and Ti-6Al-4V powder compacts sintered under a variety of induction heating conditions. Keywords: Titanium alloys, powder consolidation, powder compact sintering, induction heating.
Microstructure and Mechanical Behaviour of Ultrafine Grained Al-4wt%Cu-(2.5-10) Vol.% SiC Metal Matrix Composites Produced by Powder Compact Forging
Authors: Gazawi A. , Zhang De Liang , Pickering K.L. , Mukhtar Aamir
Published: July 2011

Ultrafine grained Al-4wt%Cu-(2.5-10) vol.% SiC metal matrix composite powders were produced from a mixture of Al, Cu and SiC powders using high energy mechanical milling (HEMM). The composite powders produced were first hot pressed at 300°C with a pressure of 240 MPa to produce cylindrical powder compacts with a relative density in the range of 80-94% which decreased with increasing the SiC volume fraction. Powder compact forging was utilized to consolidate the powder compacts into nearly fully dense forged disks. With increasing the volume fraction of SiC from 2.5% to 10%, the average microhardness of the forged disks increased from 73HV to 162HV. The fracture strength of the forged disks increased from 225 to 412 MPa with increasing the volume fraction of SiC particles from 2.5 to 10%. The Al-4wt%Cu-2.5vol.%SiC forged disk did not show any macroscopic plastic yielding, while the Al-4wt%Cu-(7.5 and 10)vol.% SiC forged disk showed macroscopic plastic yielding with a small plastic strain to fracture (~1%).
Microstructure Evolution in Nitrogen Implanted Sapphire
Authors: Kennedy John , Leveneur Jérôme , Murmu Peter P. , Markwitz Andreas
Published: July 2011

Low-energy 14N+ ions were implanted with 23 keV under normal incidence into C-axis (0001) sapphire at room temperature. DYNAMIC-TRIM calculations were performed to calculate the N depth profiles for the various fluences from 1x1016 to 1017 cm-2. Electron Beam Annealing (EBA) was performed at a sample temperature of 700 °C for 10 min to allow the implanted and substrate atoms in the implanted layer to move to energetically preferable positions. Nuclear Reaction Analysis revealed the implanted nitrogen ion concentrations. Atomic Force Microscopy and Scanning Electron Microscopy show some nanostructures at the surface of the sapphire substrate exhibiting an average width of 139 ± 25 nm and height of 37 ± 7 nm using the lowest fluence of 1x1016 ions cm-2. Notably for samples implanted with the highest fluence of 1x1017 ions cm-2, bubble/holes like structures appeared after EBA due to out-diffusion of nitrogen that causes blistering and exfoliation effects.
Effects of Thermal Exposure on Microstructure and Mechanical Properties of Ni Based Superalloy GTD111
Authors: Lee Han Sang , Yoo Keun Bong , Kim Doo Soo , Kim Jae Hoon
Published: July 2011

The rotating components in the hot sections of land-based gas turbine are exposed to severe environment during several ten thousand hours at above 1100 oC operating temperature. The failure mechanism of the hot gas components would be accompanied by material degradation in the properties of high temperature and creep rupture strength. Many hot gas components in gas turbine are made of Ni-based superalloy because of their high temperature performance. In this work, we surveyed the time and temperature dependent degradation of Ni-based superalloy. We prepared the specimens from GTD111 that are exposed at 871 oC and 982 oC in 1,000 ~ 10,000 hours. We carried out the mechanical test and microstructural observation.
Polysilicon on Insulator Structures for Sensor Application at Electron Irradiation & Magnetic Fields
Authors: Druzhinin Anatoly , Marymova Inna , Kogut Igor , Khoverko Yuriy
Published: July 2011

The effects of high energy electron irradiation and high magnetic fields (up to 14 T) on the electrical characteristics of recrystallized p-type polysilicon-on-insulator layers were studied. The aim of the paper is to obtain the material suitable to create the sensors operating in harsh conditions.
Routes towards Novel Active Pressure Sensors in SOI Technology
Authors: Olbrechts Benoit , Rue Bertrand , Pardoen Thomas , Flandre Denis , Raskin Jean Pierre
Published: July 2011

In this paper, novel pressure sensors approach is proposed and described. Active devices and oscillating circuits are directly integrated on very thin dielectric membranes as pressure transducers. Involved patterning of the membrane is supposed to cause a drop of mechanical robustness. Finite elements simulations are performed in order to better understand stress/strain distribution and as an attempt to explain the early burst of patterned membranes. Smart circuit designs are reported as solutions with high sensitivity and reduced footprint on membranes.
Effect of Ge Nanoislands on Lateral Photoconductivity of Ge-SiOX-Si Structures
Authors: Lysenko V.S. , Gomeniuk Yu.V. , Kozyrev Yu.N. , Rubezhanska M.Yu. , Skylar V.K. , Kondratenko S.V. , Melnichuk Ye.Ye. , Teichert Christian
Published: July 2011

The results of the experimental studies of the effect of nanoislands on the lateral photoconductivity in structures with Ge nanoislands formed on the SiOx layer using molecular beam epitaxy are reported. It is shown that nanoislands increase the surface recombination rate and affect the fundamental absorption edge of c-Si. The generation of lateral photocurrent in the range 0.8 – 1.0 eV was observed due to transitions between tails in the density of states of the near-surface c-Si, which is described by Urbach dependence. It was shown that the absorption spectrum of nanoislands is typical for the disordered Ge and is due to transitions between density-of-states tails of the valence and conductance bands. The mechanism is proposed of lateral photoconductivity involving the non-equilibrium charge carriers, generated in Ge nanoislands. It is suggested that the optical absorption and lateral photocurrent in Ge-SiOx-Si structures are affected by fluctuations of the surface potential in the near-surface region of c-Si, fluctuations of the Si band gap width and by effects of disorder in Ge nanoislands.