• Proceedings of the KIEE Conference
• /
• 2006.10d
• /
• pp.226-228
• /
• 2006

This paper presents a comparative study of single-phase PLL algorithms using virtual 2-phase strategy. Simulation and experimental results, including operation of the PLL structures introduced in reference papers, are presented to allow a performance comparison of the PLL algorithms.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.8 no.2
• /
• pp.219-225
• /
• 2007

The frequency and phase angle of utility voltage represent very important information fur applications such as AC/DC converters and Uninterruptible Power Supplies(UPS). In a three-phase system, the utility voltage information can be easily obtained by using a utility voltage vector. However, in the case of a single-phase system. the utility voltage information is much harder to obtain. This paper presents a comparative study of single-phase PLL algorithms using virtual 2-phase strategy. Simulation and experimental results, including operation of the PLL structures introduced in reference papers, are presented to allow a performance comparison of the PLL algorithms.

• International conference on construction engineering and project management
• /
• 2005.10a
• /
• pp.1181-1186
• /
• 2005

In many construction projects, progress and efficiency are hampered by poor communication of discipline-specific models. For example, architects use 2D or 3D CAD models and builders use CPM diagrams, Gantt charts, and spreadsheets to show their view of the project. Nowadays, advanced computer visualization tools, 4D CAD or VR, can show these disparate models to understand cross-disciplinary impacts of design and construction decisions. In Korea, several leading companies have tried to apply these tools to their pilot projects from the design phase to the maintenance phase. These companies have expected that more project stakeholders could understand a construction schedule more quickly and completely with 4D visualization than with the traditional construction management tools. However, modeling of the 4D CAD or VR can be quite time-consuming and expensive to generate manually and has therefore limited the spread and use of these models. In order to adopt widely those models in construction industry, the areas that those tools could support to take large benefits in diverse functional areas of construction management need to be analyzed. In this study, researchers analyze the usefulness and limitations of the 4D models and VR in the construction industry, develop the strategy of application priority, and improve the 4D modeling method.

• Fashion & Textile Research Journal
• /
• v.18 no.6
• /
• pp.766-775
• /
• 2016

In the era of globalization and unlimited competition, Korean universities need a breakthrough in their education system according to the changing education landscape, such as lower graduation requirements to cultivate more multi-talented convergence leaders. While each student has different learning capabilities, which results in different performance and achievements in the same class, the uniform education that most universities are currently offering fails to accommodate such differences. Blended learning, synergically combining offline and online classes, enlarges learning space and enriches learning experiences through diversified tools and materials, including multimedia. Recently, universities are increasingly adopting video contents and on-offline convergence learning strategy. Thus, this study suggests a teaching method based on blended learning to more effectively teach existing pattern CAD and virtual CAD in the Apparel Pattern CAD class. To this end, this researcher developed a teaching-learning method and curriculum according to the blended learning phase and video-based contents. The curriculum consisted of 2D CAD (SuperAlpha: Plus) and 3D CAD (CLO) software learning for 15 weeks. Then, it was loaded to the Learning Management System (LMS) and operated for 15 weeks both online and offline. The performance analysis of LMS usage found that class materials, among online postings, were viewed the most. The discussion menu most accurately depicted students' participation, and students who did not participate in discussions were estimated to check postings less than participating students. A survey on the blended learning found that students prefer digital or more digitized classes, while preferring face to face for Q&As.