On the basis of previous practice on Virtual Policing in English and related literature on Ubiquitous Learning, a scenario-based ubiquitous learning environment of English for Policing is created in which students integrate role-plays into multimedia classroom instructions, take part in simulated policing training after class, learn English and fulfill virtual policing service through QQ software on Internet-connected computers and WeChat software on smartphones. The program is implemented on free messaging tools and Virtual Policing in English Network developed with Dreamweaver, aiming at providing the students a seamless, autonomous and vocation-related learning environment anytime, anywhere with available devices. Results show that most of the participants enjoy the learning process with high interests though limitations do exist and to be overcome in the future.
Keywords: Online training, QQ, Ubiquitous learning, Virtual Policing in English Network, WeChat
[1] Abdulrahman Alsheail, Teaching English as a Second /Foreign Language in a Ubiquitous Learning Environment, Master diss., California State University, Chico, 2010.
[2] Tae-sik Ki, Towards the Design of an Interactive U-Learning System, Journal of Security Engineering,9(2), 2012,189-198.
[3] Joung-Souk Sung, U-Learning Model Design Based on Ubiquitous Environment, International Journal of Advanced Science and Technology, 13, 2009, 77-88
[4] Zhongwen Liu, Construction and Application of Scenarios in College EFL Learning, International Forum of Teaching and Studies, 8(2), 2012, 32-40.
[5] Zhongwen Liu, English for Elite Police (Press of Chinese People's Public Security University, 2009).
A time series database is a collection of well-defined data sets obtained through repeated measurements of time. The data to be examined are regularly noisy and diverse periodicity types. The existing suffix tree based periodic pattern mining algorithm can detect symbol, sequence and segment periodicity in time series data with noise filters for diverse noise kinds. But the running time desired to identify the patterns without redundancy is high. To overcome this issue, in this paper, predominant pattern distribution model is introduced with which redundant and unwanted noisy patterns are identified and discarded from it. Predominant patterns are extracted with automatic or user defined threshold of pattern of interest, generated from the dynamic online time series data. Performance of proposed framework is measured and evaluated in terms of periodic pattern mining accuracy, noise distribution rate, and predominant pattern occurrence.
Keywords: Time series, periodic pattern mining, periodicity types, suffix tree, predominant pattern distribution model.
Multilevel inverter as compared to single level inverters have advantages like minimum harmonic distortion, reduced Electro Magnetic Interference (EMI/RFI) generation and can operate on several voltage levels. In this paper a new topology of cascaded multilevel inverter using reduced number of switches, resulting in higher output voltage levels is proposed. There are five series connected H-bridges and the DC voltage is given in the ratio n0: n: n3: 2n3: 10n. The output voltage having 123 levels is obtained (61 positive voltage levels, 61 negative voltage levels and zero voltage level). The reduced Total Harmonic Distortion (THD) makes them useful for electric vehicle, flexible AC transmission and has the potential for various power applications. The proposed topology results in reduction of installation area, cost and has simplicity of control system.
Key words: Cascaded H- Bridge Multilevel Inverter (CMLI), Total Harmonic Distortion (THD), Power Quality, Switching Losses
Improving visual clarity of an image is conveniently achieved by various contrast enhancement techniques. Histogram equalization results in excess contrast enhancement. When fuzzy concepts are used for color image enhancement it creates visual artifacts. But contrast enhancement using ACO (Ant Colony Optimization) technique avoids excess contrast enhancement and visual artifacts are discussed in this paper.
Keywords: Ant colony optimization, Fuzzy logic, Histogram equalization, HSV, Image enhancement.
High pressure vessels such as gun barrels,high pressure diesel pumps are autofrettaged in order to increase their operating pressure and fatigue life. Autofrettage process helps in reducing the stress level. Autofrettage process causes plastic expansion of the inner radius of the cylinder,thereby establishing the beneficial residual compressive stresses at the bore after the de-pressurisation.The stresses developed during the subsequent pressure application,has to overcome these compressive stresses before the tensile stresses can be developed. For autofrettaged cylinder, the depth of plastic zone, or overstrain is a key factor which affects load-bearing capacity and safety.
In the current paper work, numerical simulation of the Autofrettage process was applied on to a cylinder of known dimensions with an objective to provide a better understanding of the stresses that are developed at high pressure.A comparison of reduction in stress levels between a Autofrettaged and Non-Autofrettaged cylinder has been done.It is observed that there is a reduction of 15.7% in maximum stress level for a Autofrettage pressure of 200MPa and an operating pressure of 180MPa . Also the maximum and minimum Autofrettage pressure required for autofrettage process to be carried out effeciently and the postion of maximum stresses for different autofrettage pressures have been discussed.
Keywords: Autofrettage, ANSYS, Autofrettage pressure, High pressure components, Thick walled Cylinders Tools Used: ANSYS 13.0, MATLAB, ProE
[1] Davidson, T.E. and Kendall, D.P, 1970, "The design of pressure vessels for very high pressure operation", Mechanical Behavior of Materials under Pressure, (H.L.P. Pugh, Ed.), Elsevier Co.
[2] Davidson, T.E., Barton, C.S., Reiner, A.N. and Kendall, D.P., 1962, "A new approach to the autofrettage of high strength cylinders", Experimental Mechanics, pp. 33-40
[3] Perl, M., 2000, "The change in overstrain level resulting from machining of autofrettaged thick-walled cylinder", Journal of Pressure Vessel Technology, Vol. 122, No.1, pp.9-14
[4] Perl. M., 1998,"An improved split-ring method for measuring the level of autofrettage in thick-walled cylinders", Journal of Pressure Vessel Technology, Vol. 120, pp. 69-73.
[5] Perl. M., Alperowitz, D., 1997, "The effect of crack length unevenness on stress intensity factors due to autofrettage in thick-walled cylinders", Journal of Pressure Vessel Technology, Vol. 119 , pp. 274-8.
When two rough surfaces come in contact, tip of asperities would adhere and produces resistance as friction during sliding. First Bowden and Tabor has developed adhesional friction theory based on concept of cold welding of asperity tip through plastic deformation and flow. But this simple theory could not explain for adhesional friction of lightly loaded, clean and smooth hard metallic surface contact (Like MEMS) where asperities deform elastically. In this regard, an alternative adhesional friction theory is developed based on concept of cold welding of asperity through intermolecular adhesion at the area of contact considering JKR and SB adhesion theory of elastic solid sphere.
Keywords: Surface contact, Adhesion, Adhesional loading force, Adhesional friction force, Generalized friction law
Computer recognition of sign language is an important research problem for enabling communication with hearing impaired people. This project introduces an efficient and fast algorithm for identification of the number of fingers opened in a gesture representing an alphabet of the Binary Sign Language. The system does not require the hand to be perfectly aligned to the camera. The project uses image processing system to identify, especially English alphabetic sign language used by the deaf people to communicate. The basic objective of this project is to develop a computer based intelligent system that will enable dumb people significantly to communicate with all other people using their natural hand gestures. The idea consisted of designing and building up an intelligent system using image processing, machine learning and artificial intelligence concepts to take visual inputs of sign language's hand gestures and generate easily recognizable form of outputs. Hence the objective of this project is to develop an intelligent system which can act as a translator between the sign language and the spoken language dynamically and can make the communication between people with hearing impairment and normal people both effective and efficient. The system is we are implementing for Binary sign language but it can detect any sign language with prior image processing
Keywords: Artificial Intelligence, Binary sign Language, Image Processing, Machine learning, Template Matching.
This study was carried to effect of plant residues application on nitrogen release from plant residues previously added (rice straw=RS; soybean=SY) with 15N isotope dilution technique on growth of maize with application of Twelve treatments (six treatments of addition of new plant residues and six treatments of no addition of new plant residues were arranged in a randomized block design with three replicates for each treatment resulting total of 36 pots. Five pre-germinated seeds of maize were planted in each pot and thinned to four plants after 1 week. six types of 15N labelled plant residues, i.e. biomass of rice grown under 0.0625mM N (N1T1), 0.250 mM N (N2T1), 10.0 mM N (N3T1) supplies, and biomass of soybean grown under 0.0625 mM N (N1T2), 0.250 mM N (N2T2), 10.0 mM N (N3T2) supplies. Fresh plant residue (unlabelled 15N) used for this study was obtained by growing rice and soybean for 2 months under 10.0 mM N supplied as CO(NH2)2 in solution at the rate of 400 ml/pot/day. Soils (10 kg) from each pot of experiment previously conducted were split into two parts. The first part of 5 kg of soil was treated with addition of new plant residues accordingly (unlabelled rice residue and soybean residue, supplied with 10 mM N for 3 months). This treatment was aimed to examine the influence of addition of new plant residues on N release from previously added 15N-labelled plant residues and N uptake by maize. No new plant residue was added to the second part of 5 kg of soil. This treatment was aimed to evaluate the residual N release from previously added 15N-labelled plant residues and N uptake by maize. This study concluded that rice straw residues amendment affect the soil fertility more than soybean residues sufficiently to improve growth of the subsequent crop.
Key words: Soybean,rice straw, 15N labelled, N recovery, N mineralization, N uptake
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