IJMECS Vol. 3, No. 2, Apr. 2011
Cover page and Table of Contents: PDF (size: 116KB)
In this paper the structural controllability of a class of a nonlinear system is investigated. The transfer function (matrix) of nonlinear systems is obtained by putting the nonlinear system model on non-commutative ring. Conditions of structural controllability of nonlinear systems are presented according to the criterion of linear systems structural controllability in frequency domain. An example is used to testify the presented conditions finally.[...] Read more.
College students are facing challenges to present their ideas by writing a paper because they rely more on information from computer and web. The purpose of this paper is to present a novel computer aided assessment system, to assess college students’ writing ability. The CAAS system comprises of an expert team, a set of achievement standard for assessment, and software systems to conduct data analysis and store related information. It has been used by institute in U.S. It yields face validity and consistency reliability. Objective evaluation results will be provided by randomly-assigned multiple reviewers. CAAS can assist college students improve writing skills, can describ a brief picture and detailed information for both school administrators and policy makers as well.[...] Read more.
Using graduates from the newly-upgraded colleges as a sample, we used the Wiles test on the Human Capital Hypothesis vs. the Screening Hypothesis of education economics. The results were in favor of the former, i.e., higher education was more likely a production means than just a signal in the job market. Thus the newly-upgraded colleges should adjust their curriculum and faculty structure to accommodate the skill demands in job markets.[...] Read more.
The proton exchange membrane fuel cell is an example of clean energy. Recently, a three-dimensional, steady-state non-isotherm mathematical model for proton exchange membrane fuel cell was developed for further exploration. This 3D model simultaneously takes into account the mass, momentum, energy, species, charge conservation equation as well as combines electrochemistry reaction inside the fuel cell. The simulation results reveals that it is easy to improve the fuel cell performance for higher porosity in the diffusion layer by speeding up the gas diffusion, reducing the concentration grads of gas, depressing the ridge board domino effect and falling current density grads.[...] Read more.
This paper makes analysis on theories of D-S evidential reasoning, rough sets, and extenic sets; and indicates that there are some similarities among the three theories in defining uncertainty sets. Therefore, it’s feasible to introduce relevant theories and methods of extenics into information fusion and a method of extenics fusion (MEF) is presented as well. The method combines extenic correlation function with Dempster rule and is considered a good solution for problems of evidence collision and BPA function in information fusion method based on D-S evidential reasoning. The simulation test shows that MEF is better than the traditional D-S evidential reasoning and is applicable to assess all kinds of problems. Using the method of this paper to evaluate surface water in one area of Northern China, the results were consistent with the fact.[...] Read more.
Based on the ideas of conflict-free transmission, priority to guarantee transmission quality for communication between the different clusters , this article proposes a scheduling Algorithm fit for the MAC scheme of WSNs, which has made it possible for the polling service capable of differentiating services of the cluster head node of two priority levels. The high-priority service of the cluster head is responsible for routing between the different clusters, via exhaustive service policy, while the low-priority services of the cluster head node, for communication within the cluster through limited service policy with good fairness. The theoretical model of this scheme is established through Markov chain and probability generating function. Mathematical analysis is made on the mean queue length, the mean inquiry cyclic time and the mean delay time. It turns out that the findings from theoretical analysis correspond well with those from simulated experiments.[...] Read more.
Vehicle surveillance system provides a large range of informational services for the driver and administrator such as multiview road and driver surveillance videos from multiple cameras mounted on the vehicle, video shots monitoring driving behavior and highlighting the traffic conditions on the roads. How to retrieval driver’s specific behavior, such as ignoring pedestrian, operating infotainment, near collision or running the red light, is difficult in large scale driving data. Annotation and retrieving of these video streams has an important role on visual aids for safety and driving behavior assessment. In a vehicle surveillance system, video as a primary data source requires effective ways of retrieving the desired clip data from a database. And data from naturalistic studies allow for an unparalleled breadth and depth of driver behavior analysis that goes beyond the quantification and description of driver distraction into a deeper understanding of how drivers interact with their vehicles. To do so, a model that classifies vehicle video data on the basis of traffic information and its semantic properties which were described by driver’s eye gaze orientation was developed in this paper. The vehicle data from OBD and sensors is also used to annotate the video. Then the annotated video data based on the model is organized and streamed by retrieval platform and adaptive streaming method. The experimental results show that this model is a good example for evidence-based traffic instruction programs and driving behavior assessment.[...] Read more.
There are an increasing number of DBMS vendors thinking of integrating XML data management into traditional relational database, with wider use of XML. In this case, a comprehensive evaluation methodology is needed to evaluate the XML engine in RDBMS correctly. In this paper, we analyze the characteristics of XML engine and propose an evaluation strategy of XML engine in a RDBMS. We believe that the evaluation should include functional evaluation and performance evaluation, and cover several major aspects of DB such as storage, query and update. Then we designed an evaluation scheme for the XML engine in RDBMS according the strategy. The scheme describes an evaluation scene and contains a data set, workload and index set. The data set reflects the characteristics of both data-centric and document-centric XML data. The workload covers all of the requirements of XQuery in W3C. The index set covers the aspects of storage, indexing, query and update. In the end, we complete an experiment to test an actual computer system using the proposal. The result shows that the proposal is proper.[...] Read more.