939 research outputs found

    Segmenting Taipei’s Real Estate Data – A Cluster Analysis

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    Data mining has been widely used for knowledge discovery from large amount of data. In this paper, clustering analysis is applied to Taiwan government open data platform (DATA.GOV.TW), segmenting the real estate data so as to understand the real estate market structure in Taiwan. This paper use design science research methodology (DSRM) as research method. The result provides valuable insights into market structures in Taipei City that has limited addressed in past research and contributes to real estate agencies and practitioners an insight-seeking approach that they can follow to generate values from data

    A SMIL-Based Catalog Presentation System in Electronic Commerce

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    Web-based catalog presentations play the key-enabling role in E-commerce in recent years. Existing catalog systems often acquire proprietary platforms, cannot deal with TV-like media objects, or consume network bandwidth inefficiently. With the emergence of advanced technologies of Web and multimedia, such hurdles can be removed. The Synchronized Multimedia Integration Language (SMIL), proposed by W3C allows Web designers to design complicated and vivid multimedia presentations in a declarative manner. These presentations are then rendered on a general-purpose browser by a SMIL player. Since the SMIL specification is quite new to the Internet and E-commerce societies, the functionality and applications of players is limited. In this paper, we propose a novel architecture based on Java JMF technology for tackling with such constraints. The effectiveness of the proposed system is validated through an experiment on product catalog presentations

    CFD Analysis of Oil Distribution in Oil-injected Screw Compressor

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    Oil-injected screw compressor has been used in various industries. After decades of continuous research efforts by research teams around the world, the computer tools for rotor profile design, thermodynamic analysis, CFD/CAE calculation, and moving grid generation have been well developed and widely employed in design works. With assistance from the computer tools in performance simulation, designers could clearly understand internal phenomena of a screw compressor, as a reference for performance optimization design, and systematically carry out research works. One important issue inside an oil-injected screw compressor is about oil distribution. Different oil-injected positions and quantities cause different oil distribution inside the compressor. Therefore, the effects of oil sealing and lubrication change. Designers must understand how oil distribution is to deal with oil issues. In this study, CFD analysis was done with dynamic grid technology. Basic performance of screw compressor was calculated and compared with experiment data. Besides, three CFD models with different oil-injected paths were designed and analyzed. The influence of varying oil-injected conditions on oil distribution near contact line, sealing lines, blow holes, and end sides of inlet and outlet are shown in this study. They are used to explain how volumetric efficiency is affected. Especially for oil distribution near contact line, it not only affects volumetric efficiency, but also acts on the lubrication as rotor meshing

    Application of Computational Fluid Dynamics to the Lubrication Study of an Oil-injected Screw Compressor

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    Computational fluid dynamics and mesh generation tools have been well developed, and could be used to calculate the performance of an oil-injected screw compressor. Designers could now effectively obtain reliable results of efficiency, temperature, force and torque. Some physical phenomena inside a screw compressor are not easy to be observed through experiments, such as the oil distribution and the oil film thickness on the rotor surface. Under the ideal lubrication condition, the oil film of proper thickness should be maintained on the local surfaces which are going to contact with each other. This could be numerically explored by computational fluid dynamics. The first case in this study showed the effect of centrifugal force on a thin free surface flow on the rotor surface. Designers could graphically understand how the oil film flows on the rotor surface when rotors separately rotate without meshing with each other and doing the compression work. The second case in this study was the rotor lubrication. The clearance distribution between rotors in the actual contact area was designed by the minimum film thickness and was 1 ÎĽm. The pressure gradient on the rotor surface was used to see if the hydrodynamic pressure appeared. Designers could optimize the design of oil injection not only by considering efficiencies, but also by analyzing the pressure gradient and the oil film distribution on rotor surfaces

    Chiral microstructures (spirals) fabrication by holographic lithography

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    We present an optical interference model to create chiral microstructures (spirals) and its realization in photoresist using holographic lithography. The model is based on the interference of six equally-spaced circumpolar linear polarized side beams and a circular polarized central beam. The pitch and separation of the spirals can be varied by changing the angle between the side beams and the central beam. The realization of the model is carried out using the 325 nm line of a He-Cd laser and spirals of sub-micron size are fabricated in photoresist.Comment: 6 page

    A Comparison of Thermal Deformation of Scroll Profiles inside Oil-free Scroll Vacuum Pump and Compressor via CAE/CFD Analysis

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    Scroll machine is simply constructed by fixed and orbit scrolls, rotary shaft, and some mechanical components. It can impressively operate at low noise level with high reliability and high efficiency. Scroll machine achieves oil-free application through reasonable clearance control, cooling solution, and the tip seal application, and has been designed and applied as vacuum pump or compressor. In order to compactly design structure and optimize the gaps or clearances of a scroll machine, the issue of heat deformation must be considered. Deformation inside a scroll machine is not easy to be discovered, but is the necessary information for scroll profile design. In this study, the internal flow fields of oil-free scroll vacuum pump and compressor are obtained by CFD analysis. Based on the results of flow fields, this study shows the basic performance of a scroll machine, including loading on structures, gas torque, volume flow rate, and the pulsation of outlet pressure. The fluid phenomena under sub-atmospheric and positive pressure are quite different. The difference would cause different heat transfer and heat deformation. Therefore, the fluid-thermal-solid coupling analysis is also carried out. The temperature distribution of scroll structures, the thermal deformation, and gap changes are also discussed in this study

    A retrospective study of magnetic resonance-guided focused ultrasound ablation for uterine myoma in Taiwan

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    AbstractObjectiveTo report our experiences with 40 patients who were treated with magnetic resonance-guided focused ultrasound surgery (MRgFUS) for uterine fibroids and their 6-month follow-up status.Materials and MethodsA total of 40 patients with uterine fibroids underwent MRgFUS from January 2009 to November 2011. The Uterine Fibroid Symptoms and Quality of Life Questionnaire was used to determine the patients' Symptom Severity Scores (SSS) prior to and 6 months after treatment. The nonperfused volume (NPV) values and NPV ratio were obtained immediately at the end of the treatment and at 6 months follow-up.ResultsNo procedure-related complications were noted throughout the 6-month follow-up period among the 40 patients who underwent MRgFUS for uterine fibroids. The mean reduction in SSS in our patients after 6 months was 43.7%, and the mean reduction of fibroid volume was 31.7%. In addition, the mean reduction of NPV and mean NPV ratio was 52.7% and 33.3%, respectively.ConclusionThe results obtained from this study demonstrated that MRgFUS can be safely and effectively used to ablate uterine fibroids to produce a significant decrease in mean fibroid volume and improve SSS for up to 6 months after treatment
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