11,352 research outputs found
A 77GHz on-chip microstrip patch antenna with suppressed surface wave using EBG substrate
This paper presents the design of a patch antenna with suppressed surface waves by means of applying an electromagnetic band-gap structure. Establishing th
e antenna on high dielectric substrate such as Silicon makes it possible to
integrate the antenna with RFIC active component and circuitry. However, the performance (gain and radiation pattern) of antenna will be degraded due to the presence of surface waves on a thick dielectric substrate. It is possible to des
ign an engineered substrate that filters out the surface wave around the frequency of interest. Moreover, having high dielectric substrate will localize EM wave to substrate and hence reduce antenna gain. For this problem, available silicon etching technology is used to remove the substrate right under the patch and have a locally low dielectric constant substrate underneath the antenn
a. Proposed microstrip antenna resonates at 77GHz with 7dB realized gain which can be used in array for Automotive Radar purposes. Simulation results show great improvement in radiation pattern and 3dB increase in antenna's broadside gain in comparison with antenna on normal substrate
Determining the basic principles in managing project schedule for construction.
The application of the scheduling software has been quite popular in Malaysia recently. Planning software like Microsoft Project and Primavera had been used to develop the schedule for construction project for the purpose or project monitoring and control. Many clients organization have made the task to submit computer generated schedule as mandatory. However in real practice the schedule submitted has not been very useful for the client. In some instances the schedule has been ignored once submitted to the client. There are many problems associated to this situation. Among them is due to the absent of the standard guideline that can be used to manage the schedule itself. The contractor. Contractor has been prepared the schedule based on their own assumption and without much consideration for actual application for the project later. Therefore this short term research has been conducted with the main aim to develop such guideline. The methodology adopted for the study includes the interviews with panel of professional in construction and questionnaire survey. The development of the guideline is based on the feedback by the respondents of the questionnaires survey conducted. Prior to that, the research has also investigated the current state of arts of the scheduling practice in Malaysia and its limitation. The major finding of the research is the development of the guideline for managing the scheduling process. This guideline can be used by the major client to regulate the process of preparing, submission and updating the project progress. It is expected that this schedule can be improve further by improving its level of comprehensiveness
The analysis of Iran universities’ 2003-2004 entrance examination to detect biased items
Item bias or differential item function (DIF) refers to the situation in which the probability of correct responses to an item for examinees with equal ability measured by test but belong to different groups are not equal. The existence of bias in items decreases the validity of the test. In this study the range of item difficulty among surveyed groups, has been used as a method for detecting the item bias in Persian literature subtest as part of the Entrance Examination to Universities of Iran in 2003-2004. For this purpose, report cards of 5000 (each group of 1000 examinees) participants in this examination from three provinces i.e. Yazd, Azerbaijan Sharghi and Kurdistan as sample groups were analyzed using the computerized program, BILOG-MG. Out of 25, two items, numbers 9 and 10 showed bias between gender groups and both were in favour of female group and were identified as biased items. Of this number, four items numbers 2, 7, 9, and 12 showed bias among linguistic groups
Optical Waveguide Modelling Based On Scalar Finite Difference Scheme
A Numerical Method Based On Scalar Finite Difference Scheme Was Adopted And Programmed On MATLAB® Platform For Optical Waveguide Modeling Purpose. Comparisons With Other Established Methods In Terms Of Normalized Propagation Constant Were Included To Verify Its Applicability. The Comparison Results Obtained Were Proven To Have The Same Qualitative Behaviour. Furthermore, The Performances Were Evaluated In Terms Of Computation Complexity, Mesh Size, And Effect Of Acceleration Factor. Computation Complexity Can Be Reduced By Increasing The Mesh Size Which Will Then Produce More Error. The Problem Can Be Rectified By Introducing The Acceleration Factor, Successive Over Relaxation (SOR) Parameter. It Shows That SOR Range Between 1.3 And 1.7 Can Give Shorter Computation Time, While Producing Constant Value Of Simulation Results
Polymer optical waveguide based n wet-chemical fabrication process
The wet-chemical fabrication process of BenzoCyclobutene (BCB 4024-40) polymer waveguides are described. The method of prism coupling is adopted in the characterization process of the polymer film. A cost effective chemical etching technique is used in the waveguide fabrication process to take advantage of the photosensitive nature of the polymer. The waveguide loss is measured using the conventional cut back method which results on an average loss of 3.5 dB/cm
Specification and Verification of Context-dependent Services
Current approaches for the discovery, specification, and provision of
services ignore the relationship between the service contract and the
conditions in which the service can guarantee its contract. Moreover, they do
not use formal methods for specifying services, contracts, and compositions.
Without a formal basis it is not possible to justify through formal
verification the correctness conditions for service compositions and the
satisfaction of contractual obligations in service provisions. We remedy this
situation in this paper. We present a formal definition of services with
context-dependent contracts. We define a composition theory of services with
context-dependent contracts taking into consideration functional,
nonfunctional, legal and contextual information. Finally, we present a formal
verification approach that transforms the formal specification of service
composition into extended timed automata that can be verified using the model
checking tool UPPAAL.Comment: In Proceedings WWV 2011, arXiv:1108.208
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