• World Technopolis Review
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• v.8 no.1
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• pp.59-70
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• 2019

Where is a better place to live? In the coming era, this should be more than simply a livable place. It should be an adaptable place that has a flexible system adaptable to any new situation in terms of diversity. Customization and real-time operation are needed in order to realize this technologically. We expect a smart city to have a flexible system that applies technologies of self-monitoring and self-response, thereby being a promising city model towards being a better place to live. Energy demand and supply is a crucial issue concerning our expectations for the flexible system of a smart city because it is indispensable to comfortable living, especially city living. Although it may seem that energy diversification, such as the energy mix of a country, is a matter of overriding concern, the central point is the scale of place to build grids for realizing sustainable urban energy systems. A traditional hard energy path supported by huge centralized energy systems based on fossil and nuclear fuels on a national scale has already faced difficult problems, particularly in terms of energy flexibility/resilience. On the other hand, an alternative soft energy path consisting of small diversified energy systems based on renewable energy sources on a local scale has limitations regarding stability, variability, and supply potential despite the relatively light economic/technological burden that must be assumed to realize it. As another alternative, we can adopt a holonic path incorporating an alternative soft energy path with a traditional hard energy path complimentarily based on load management. This has a high affinity with the flexible system of a smart city. At a system level, the purpose of all of the paths mentioned above is not energy itself but the service it provides. If the expected energy service is fixed, the conclusive factor in choosing a more appropriate system is accessibility to the energy service. Accessibility refers to reliability and affordability; the former encompasses the level of energy self-sufficiency, and the latter encompasses the extent of energy saving. From this point of view, it seems that the small diversified energy systems of a soft energy path have a clear advantage over the huge centralized energy systems of a hard energy path. However, some insuperable limitations still remain, so it is reasonable to consider both energy systems continuing to coexist in a multiplexing energy system employing a holonic path to create and maintain reliable and affordable access to energy services that cover households'/enterprises' basic energy needs. If this is embodied in a smart city concept, this is nothing else but smart energy inclusion. In Japan, following the Fukushima nuclear accident in 2011, a trend towards small diversified energy systems of a soft energy path intensified in order to realize a nuclear-free society. As a result, the Government of Japan proclaimed in its Fifth Strategic Energy Plan that renewable energy must be the main source of power in Japan by 2050. Accordingly, Sony vowed that all the energy it uses would come from renewable sources by 2040. In this situation, it is expected that smart energy inclusion will be achieved by the Japanese version of a smart grid based on the concept of a minimum cost scheme and demand response.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.1
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• pp.155-161
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• 2015

The energy storage system is actively used as the widespread of smart grid. In the case of large scale EES, it can be efficiently controlled linked with BEMS or BAS. But, in the case of EES installed in a small sized household, it needs the help of the remote control system because it lacks the expert for controlling and operating of EES. In addition, in the case when the solar energy generation and EES are installed at the same time, a small sized EMS which can be efficiently controlled depending on the solar energy generation or electric power load is needed. In this paper, the EMS which can efficiently control the solar power generation as well as EES installed in a small sized household is implemented and its usefulness is verified through some experimental studies.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.7B
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• pp.1091-1097
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• 2010

Energy and environment problem has been arisen and become one of the major concerns all over the world, due to scarce energy resources and inefficient energy consumption. Recently, energy-IT(EIT) convergence technology has been getting more attention, being expected to be one of key technologies to resolve the problem, and R&D projects on various areas of EIT convergence technologies have been launched in many countries on a large scale. Korea government and companies have also been interested in the development of EIT technologies, however, the scopes of technology areas are limited to just a small part such as smart grid technology. This paper investigates effectiveness of each EIT convergence technology and deduces EIT convergence technologies using AHP(Analytic Hierarchy Process). It is expected that our research could be meaningful information supporting policies on R&D projects of EIT convergence technologies promoted to save energy and strengthen the national competitiveness. Our research results show that the EIT convergence technology area of green building would be the most effective EIT convergence technology except smart grid, and network-based energy management system would be the most effective amongst the sub-areas of green building.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.2005-2006
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• 2011

Due to the advantages of small sizes, more I/O ports, etc., Ball Grid Array (BGA) has been used in the production of printed circuit board (PCB). However, BGA voids can degrade the performance of the board and cause failure. To automatically detect the voids in X-ray image, a novel blob filter that makes use of the local image gradient magnitude is proposed in this paper. The utilization of the local image gradient magnitude makes the proposed filter invariant to the image brightness, void shape, void position, and component interference. Furthermore, different sizes of box filters are employed to analyze the image in multi-scale, and as a result, the proposed blob filter is robust to void size. Experimental results show that the proposed method can obtain void detection accuracy up to 96.104% while keep low false ratio.

• Proceedings of the KSME Conference
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• 2001.11b
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• pp.499-504
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• 2001

A validation of a 3D CFD model for predicting local subcooling of moderator in the vicinity of calandria tubes in a CANDU reactor is performed. The small scale moderator experiments performed at Sheridan Park Experimental Laboratory(SPEL) in Ontario, Canada[1] is used for the validation. Also a comparison is made between previous CFD analyses based on 2DMOTH and PHOENICS, and the current model analysis for the same SPEL experiment. For the current model, a set of grid structures for the same geometry as the experimental test section is generated and the momentum, heat and continuity equations are solved by CFX-4.3, a CFD code developed by AEA technology. The matrix of calandria tubes is simplified by the porous media approach. The standard $k-\varepsilon$ turbulence model associated with logarithmic wall treatment and SIMPLEC algorithm on the body fitted grid are used and buoyancy effects are accounted for by the Boussinesq approximation. For the test conditions simulated in this study, the flow pattern identified is a buoyancy-dominated flow, which is generated by the interaction between the dominant buoyancy force by heating and inertial momentum forces by the inlet jets. As a result, the current CFD moderator analysis model predicts the moderator temperature reasonably, and the maximum error against the experimental data is kept at less than $2.0^{\circ}C$ over the whole domain. The simulated velocity field matches with the visualization of SPEL experiments quite well.

• Fire Science and Engineering
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• v.31 no.5
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• pp.12-18
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• 2017

The present study has been conducted to predict the mass burning flux of methanol pool fire using liquid vaporization model in FDS and examine the effect of thermal properties of liquid fuel such as radiative fraction and mean absorption coefficient. A series of calculation for the pool diameter of 5 cm to 200 cm were performed and the size of computational domain was determined by the scale of the pool diameter. The reference grid size was determined by the grid sensitivity analysis and the computational grids consisted of approximately 750,000 cells. For the methanol pool fire, the mass burning flux predicted by liquid vaporization model of FDS followed the trend of transient characteristics as a function of pool diameter and showed good agreement within measurement uncertainty range of previous studies. The mass burning flux increased with increasing the radiative fraction and the mean absorption coefficient greatly affected on relatively small pool diameter.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2000.11a
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• pp.221-227
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• 2000

The optimal capacity of CGS(Co-Generation Sys.) for APT. complex is 300kW output of electricity power from being considered the simple payback period, loss and benefit, and the running mode of CGS. The proper operation mode of CGS is as follows; If the demanding electricity load of APT. complex is within the range of capacity of generator(300kW), CGS is connected and operated with KEPCO grid. When the load ratio is over 50% of normal load of CGS(300kW), only CGS supply electricity demand. If not, the electricity line of CGS is exchanged to that of KEPCO.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.12
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• pp.56-61
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• 2012

There have been a lot of reports about the effects of geomagnetically induced current(GIC) on the power grids. However there has been little domestic efforts made in this relatively urgent area which include academic research or risk assessments on GIC. There still exist a claim that domestic power grids might be in the safe state from GIC since our geomagnetic latitude is low and our power grid is relatively small scale. However it has been already demonstrated that GIC has an effect on power grids located at all latitudes. In this study, we have reviewed the transpiratory principle of the GIC, case studies of the major damage in various regions and we have calculated the GIC that can occur in domestic power grids. This paper presents some of the fundamental information about the risk assessment of domestic power grids from GIC although more thorough investigation should be made to ensure the safe operation of nationwide electric power infrastructure.

• Journal of the Korea Convergence Society
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• v.8 no.9
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• pp.25-30
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• 2017

The Connected House is a new type of IT convergence service that combines new communication services with existing IT systems such as M2M, NFC, smart home, and smart grid. It is a future connected life service that connects to any device anytime, anywhere. In this paper, we designed an intelligent gateway, a connected office solution for the Internet of things, which provides a connected life service for the future, and can control various sensors, ZigBee/Z-Wave/NFC and terminal devices. In addition, IP/SIP/IMS cameras and video door phones that are linked to the gateway have been developed to satisfy the quality standards of domestic communication service providers in terms of voice quality, jitter, and frame rate.

• The Journal of Korea Robotics Society
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• v.16 no.2
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• pp.112-121
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• 2021

Unlike a typical small-sized robot navigating in a free space, an autonomous vehicle has to travel in a designated road which has lanes to follow and traffic rules to obey. High-Definition (HD) maps, which include road markings, traffic signs, and traffic lights with high location accuracy, can help an autonomous vehicle avoid the need to detect such challenging road surroundings. With space constraints and a pre-built HD map, a new type of path planning algorithm can be conceived as a substitute for conventional grid-based path planning algorithms, which require substantial planning time to cover large-scale free space. In this paper, we propose an obstacle-avoiding, cost-based planning algorithm in a continuous space that aims to pursue a globally-planned path with the help of HD map information. Experimentally, the proposed algorithm is shown to outperform other state-of-the-art path planning algorithms in terms of computation complexity in a typical urban road setting, thereby achieving real-time performance and safe avoidance of obstacles.