• Korean Journal of Optics and Photonics
• /
• v.24 no.5
• /
• pp.237-244
• /
• 2013

Supermultiview and electro-holographic displays are promising displays for the future because they provide continuous parallaxes as their depth cue. But they are still in the early development stage due to the lack of supporting technologies. Achieving the continuous parallax in the supermultiview relies more on the number and size of pixels in the pixel cell/elemental image rather than the number of different view images. For the electro-holographic display, it also relies on the number and size of pixels in the panel. So these two methods share the same requirements for achieving the parallax. But the image displayed on the holographic display provides more impressive visual appeal than that on the supermultiview because the image can be floated on the front space of the display.

• Smart Structures and Systems
• /
• v.6 no.5_6
• /
• pp.731-748
• /
• 2010

Impact detection and health monitoring are very important tasks for civil infrastructures, such as bridges. Piezoceramic based transducers are widely researched for these tasks due to the piezoceramic material's inherent advantages of dual sensing and actuation ability, which enables the active sensing method for structural health monitoring with a network of piezoceramic transducers. Wireless sensor networks, which are easy for deployment, have great potential in health monitoring systems for large civil infrastructures to identify early-age damages. However, most commercial wireless sensor networks are general purpose and may not be optimized for a network of piezoceramic based transducers. Wireless networks of piezoceramic transducers for active sensing have special requirements, such as relatively high sampling rate (at a few-thousand Hz), incorporation of an amplifier for the piezoceramic element for actuation, and low energy consumption for actuation. In this paper, a wireless network is specially designed for piezoceramic transducers to implement impact detection and active sensing for structural health monitoring. A power efficient embedded system is designed to form the wireless sensor network that is capable of high sampling rate. A 32 bit RISC wireless microcontroller is chosen as the main processor. Detailed design of the hardware system and software system of the wireless sensor network is presented in this paper. To verify the functionality of the wireless sensor network, it is deployed on a two-story concrete frame with embedded piezoceramic transducers, and the active sensing property of piezoceramic material is used to detect the damage in the structure. Experimental results show that the wireless sensor network can effectively implement active sensing and impact detection with high sampling rate while maintaining low power consumption by performing offline data processing and minimizing wireless communication.

• Korean Journal of Materials Research
• /
• v.32 no.3
• /
• pp.146-152
• /
• 2022

One disadvantage of deep cycle flooded lead-acid batteries is increasing water loss caused by use of (+) Pb-Sb / (-) Pb-Sb alloy grid. Water loss is generated by the emission of hydrogen gas from the (-) electrode during battery charging. In this paper, we maintain cycle life aspect through the development of hybrid flooded lead-acid batteries to which a (+) Pb-Sb / (-) Pb-Ca grid is applied and deal with the improvement of water loss. The amount of water loss compared to that of the (-) Pb-Sb grid decreased when Ca was added to the (-) Pb grid. For the (-) Pb-Ca grid, it was confirmed that the time to reach 0.0 V, at which water decomposition occurs, was increased compared to that of the (-) Pb-Sb grid at the NPV (Negative Potential Voltage). In the cycle life test conducted with the BCI (Battery Council International) standard, compared to the (+) Pb-Ca grid, the (+) Pb-Sb grid increased the life cycle of the batteries and the (+) Pb-Ca grid showed an early end of life due to PbO corrosion layer generation, as determined through SEM / EDS and Tear Down analysis. In conclusion, by addition of Sb to (+) Pb grid and Ca to (-) Pb grid, we developed a hybrid flooded lead-acid battery that meets user requirements to improve water loss characteristics and preserve cycle life characteristics.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.39 no.3
• /
• pp.71-82
• /
• 2016

The ISO (International Organization for Standardization) 9000 QMS (Quality Management System) standards specify requirements that need to demonstrate an organization's ability to consistently provide products or services. Korean companies have been implementing ISO 9000 QMS to compete in global markets. ISO 9000 QMS standards have been revised in 1994, 2000, 2008, and 2015 since the first release in 1987. The key change in ISO 9001:2015 is focused on risk-based thinking. It means that risk inherent within an organization is early identified and proactively controlled by use of all aspects of QMS rather than taking preventive actions. In this article we did literature review mainly on empirical study related to motivation and operation performance of ISO 9000 implementation. We present the necessity of changeover, features of new version, and comparison between new and old version. In order to see how well organizations can implement the new ISO 9001:2015 we focus on manufacturing companies that are going to convert to ISO 9001:2015 registration. We collect their key characteristics such as yearly sales, the number of MPI (Management Performance Indicators), the number of KPI (Key Performance Indicators), the number of quality control engineers, quality control engineer work experience, and the degree of adaptiveness between new ISO 9001:2015 QMS and QMS currently operating in manufacturing companies. Especially the degree of adaptiveness is analyzed by correlation analysis, regression analysis, ANOVA, and t-tests to discover the relationships among their characteristics. We found out that the degree of adaptiveness is linearly related to quality control engineer work experience and the number of MPI and KPI that is practically utilized in manufacturing companies. We summarize the implications discovered to help manufacturing industry convert to ISO 9001:2015 registration.

• Korean Journal of Construction Engineering and Management
• /
• v.19 no.6
• /
• pp.34-45
• /
• 2018

Nuclear power plant(NPP) is a large-sacle national infrastructure with total project cost of 77 billion dollars and period of 10 years or more. Moreover, since it is operated over 60 years, NPP is a facility closely related to national economy and public safety. Therefore, accurate information and consistent physical configuration should be maintained to enable accurate and economical decision making in NPP project process such as design, construction, operation, and decommission. Since NPP industry is more complicate and regulated than other industries, the importance of configuration management(CM) has been widely recognized in the early days. However, there were limitations in implementing systematic CM due to unclear purpose and subject. Therefore, this paper suggests a room-based database for CM in NPP reflects design requirements and facility configuration information.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.20 no.10
• /
• pp.1949-1954
• /
• 2016

Smart grid technology can be called grid techniques to improve the efficiency of the electric power by exchanging bidirectional information of electric power with real-time between electric power suppliers and consumers. Recently, the solar power generation system is being applied actively. However the solar power system has several problems leading to reduce overall electricity generation, because the difficult of the diagnosis and the solar power system failure such as PV(PhotoVoltaics) and inverter. In order to build an efficient smart grid, a stable electric power energy requirements capture and management and early fault detection is essentially required in solar power generation system. In this paper, it is designed to monitor the operating status of the solar power monitoring system from a remote location through a RS-485 or TCP/IP communication module to monitoring the output of solar power energy and abnormal phenomenon, to developing the measurement module and to transfer measured data.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.25 no.10
• /
• pp.1020-1027
• /
• 2014

ISO 26262 is applied to vehicle and electrical/electronic component manufacturers for minimizing car accidents and life damage by the extended use of electronic control equipments and their malfunctions. In this standard, safety requirements are required to be applied from the early stage of development upto manufacture and disposal stages throughout the total lifecycle of the full vehicular system, and electromagnetic compatibility must be also managed as an important consideration factor. Therefore, it is nowadays very necessary to research and develop EFS(EMC for Functional Safety) to be applied in each stage of the design, manufacture, accreditation, use, maintenance stages of cars. In this paper, how EFS can be applied for the application of ISO 26262 is described. By the enforcement of this suggestions into the legal requirement or New Car Assessment Program(NCAP) test items, it is necessary that car manufacturer have to perform some procedures for ensuring car safety by themselves.

• Journal of the Korea Institute of Building Construction
• /
• v.14 no.2
• /
• pp.156-162
• /
• 2014

This study aims to develop a rapidly hardening type of concrete to achieve the removal of form intensity (more than 10MPa) using the method of curing at room temperature in order to solve some economic environmental problems by omitting the steam curing process involved in producing PC (Precast Concrete). Therefore, this study evaluated a rapidly hardening cement containing a high amunt of C3S, which is very responsive in expressing early intensity, and a rapidly hardening type of concrete which uses some hardening accelerator to increase thehydration reaction of $C_3S$. The results of the experiment on concrete using some hardening accelerator are asfollows. In the slump flow experiment for identifying the liquidity and the air test, the desired values were met. The compression strength showed rapid expression response by 12 hours, and met the desired value within 6~9 hours. Its drying shrinkage value and Autogenous shrinkage value were measured as below ($-754.5{\times}10^{-6}$),and satisfied the requirements. In addition, in the Semi-Adiabatic Temperature Test, it was found that the concrete rose to its peak temperature within 24 hours and then its temperature dropped.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.39 no.4
• /
• pp.293-299
• /
• 2015

Various centrifugal compressors are currently used extensively in industrial fields, where the design requirements are more complicated. This makes it more difficult to determine the optimal design point of a centrifugal compressor. Traditionally, the efficiency is an important factor for optimization. In this study, the weight of the compressor was also considered. The aim of this study was to present the design tendency considering the stage efficiency and weight. In addition, this study suggested possibility of a selection of compressor design objectives at an early design stage based on the optimization results. Only a vaneless diffuser was considered in this case. The Kriging method was used with sample points from 1D design program data. The optimal points were determined in a substitute design space.

• Journal of Power System Engineering
• /
• v.9 no.2
• /
• pp.81-87
• /
• 2005

This study is numerical analysis on the increasing temperature characteristics of vaporizer fin for liquefied natural gas with super low temperature. Existing LNG vaporizers use the direct contact heat transfer mode where the extreme super low temperature LNG of $-162^{\circ}C$ flows inside of the tubes and about $20^{\circ}C$air flows on outside of the fin. Recently, the vaporizers with great enhanced performance compared to conventional type have been developed to fulfill these requirements. The vaporizing characteristic of LNG vaporizer with air as heat source has a fixed iced. These characteristic cause a low efficiency in vaporizer, total plant cost and installing space can be increased. The vaporizing characteristics of LNG via heat exchanger with air are analytically studied for an air heating type vaporizer. This study is intended to supply the design data for the domestic fabrication of the thickness and angle vaporizer fin. Governing conservation equations for mass, momentum and energy are solved by STAR-CD based on an finite volume method and SIMPLE algorithm. Calculation parameter is fin thickness, setup angle and LNG temperature. If the vaporization performance of the early stage and late stage of operating is considered, the case of ${\phi}=90^{\circ}$ was very suitable. In this paper was estimated that the heat transfer was most promoted in case of THF=2mm.