• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.3
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• pp.1002-1015
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• 2018

The advent of Internet of Things (IoT) and the evident inadequacy of Cloud networks concerning management of numerous end nodes have brought about a shift of paradigm giving birth to Fog computing. Fog computing is an extension of Cloud computing that extends Cloud resources at the edge of the network, closer to the user. Cloud computing has become one of the essential needs of people over the Internet but with the emerging concept of IoT, traditional Clouds seem inadequate. IoT entails extremely low latency and for that, the Cloud servers that are distant and unknown to the user appear to be unsuitable. With the help of Fog computing, the Fog devices installed would be closer to the user that will provide an immediate storage for the frequently needed data. This paper discusses data migration between different storage types especially between Cloud devices and then presents a mechanism to migrate data between Cloud and Fog Layer. We call this mechanism Adaptive Deadline-Aware Scheme (ADAS) for Data migration between Cloud and Fog. We will demonstrate that we can access and process latency sensitive "hot" data through the proposed ADAS more efficiently than with a traditional Cloud setup.

• Earthquakes and Structures
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• v.15 no.4
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• pp.411-417
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• 2018

To solve the seismic response problem of a vertical floating roof tank with base isolation, the floating roof is assumed to experience homogeneous rigid circular plate vibration, where the wave height of the vibration is linearly distributed along the radius, starting from the theory of fluid velocity potential; the potential function of the liquid movement and the corresponding theoretical expression of the base shear, overturning the moment, are then established. According to the equivalent principle of the shear and moment, a simplified mechanical model of a base isolation tank with a swinging effect is established, along with a motion equation of a vertical storage tank isolation system that considers the swinging effect based on the energy principle. At the same time, taking a 150,000 m 3 large-scale storage tank as an example, a numerical analysis of the dampening effect was conducted using a vibration mode decomposition response spectrum method, and a comparative analysis with a simplified mechanical model with no swinging effect was applied.

• Proceedings of The Korean Society of Agricultural and Forest Meteorology Conference
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• 2003.09a
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• pp.189-201
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• 2003

Grid is a new Information Technology (IT) concept of "super Internet" for high-performance computing: worldwide collections of high-end resources - such as supercomputers, storage, advanced instruments and immerse environments. The Grid is expected to bring together geographically and organizationally dispersed computational resources, such as CPUs, storage systems, communication systems, real-time data sources and instruments, and human collaborators. The term "the Grid" was coined in the mid l990s to denote a proposed distributed computing infrastructure for advanced science and engineering. The term computational Grids refers to infrastructures aimed at allowing users to access and/or aggregate potentially large numbers of powerful and sophisticated resources. More formally, Grids are defined as infrastructure allowing flexible, secure, and coordinated resource sharing among dynamic collections of individuals, institutions and resources referred to as virtual Organizations. GRID is an emerging IT as a kind of next generation Internet technology which will fit very well with Agrometeorological services in the future. I believe that it would contribute to the resource sharing in AgroMeteorology by providing super computing power, virtual storage, and efficient data exchanges, especially for developing countries that are suffering from the lack of resources for their agmet services at national level. Thus, the establishment of CAgM-GRID based on existing RAMINSII is proposed as a part of FWIS of WMO.part of FWIS of WMO.

• Korean Journal of Food Science and Technology
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• v.22 no.3
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• pp.300-306
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• 1990

The microstrutural changes of mayonnaise during storage were examined by light microscopy (LM) and scanning electron microscopy (SEM). Fresh mayonnaise was composed of heterogenous population of dispersed spherical oil droplets and droplet size was normally distributed with one mode. During storage at $60^{\circ}C\;and\;-10^{\circ}C$, a shift in droplet size distribution toward larger droplets was observed, as a result of coalescence of lipid droplets. Turbidimetric study also confirmed that coalescence was occurring during this accelerated aging treatments. Measurements obtained from SEM microgrphs provided better determination of smaller droplets and resulted in lower mean diameter of droplets than those obtained from LM. From these results, SEM was found to be an advantageous method of examining emulsion products as compared to LM, providing a better resolution of small droplets and a more representative view of droplet distribution, as dilution of the sample was avoided.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.4
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• pp.616-622
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• 2015

A microgrid which is composed of distributed generation systems, energy storage systems and loads is operated in the grid-connected mode and in the islanded mode. Especially, in the islanded mode, a microgrid should maintain frequency in the allowed range. The frequency is decided by a balance between power supply and power demand. In general, the frequency is controlled by using battery energy storage systems (BESSs) in the microgrid. Especially, droop control is applied to controlling BESSs in the microgrid. Meanwhile, over-charging and deep-discharging of BESS in operation and control cause life-shortening of batteries. In this paper, a fuzzy droop control is proposed to change droop gains adaptively by considering state of charge (SOC) of BESSs to improve the life cycle of the battery. The proposed fuzzy droop control adjusts droop gains based on SOC of BESSs in real time. In other to show the performance of the proposed fuzzy droop control, simulation based on Matlab/Simulink is performed. In addition, comparison of the convention droop control and the proposed fuzzy droop control is also performed.

• Fashion & Textile Research Journal
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• v.12 no.4
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• pp.513-522
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• 2010

The aim of this study is to investigate the actual state for the development of the thermally comfortable uniform for workers on a low temperature storage. Observation, interview and survey were executed focusing on the environment, clothing, and human factors which have effects on the comfort of workers. Of 400 distributed, 253 questionnaires were analyzed through descriptives, frequency, ANOVA, t-test, multi-response analysis, correlation analysis with SPSS 12.0. The results are following. Coming and going between a selling area and cold storages, the workers showed to experience a big temperature gap. They indicated to feel cold on face and hands which were not covered by clothing and have got sick because of low temperature. The workers wanted the uniform made of functional fabrics, especially heat insulation fabrics. Female workers rather than male workers, the older, and the longer their working period were, the more uncomfortable they revealed to feel. The workers who works on the daily products part or mainly on the freezer appeared to feel cold more than any other workers. In conclusion, it was found that the uniform which consider steady state and unsteady state heat transfer together must be developed.

• Transactions of the Korean Society of Automotive Engineers
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• v.3 no.5
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• pp.64-73
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• 1995

A numerical simulation of heat and fluid flow for predicting the effect of passage arrangement in automotive heat battery has been performed. The system is assumed to be a two-dimensional laminar flow and isothermal boundary is applied to the surface of the latent heat storage vessel. In the case of ideal heat battery the flow rate into each flow passage is evenly distributed. The various models are considered in the view of pressure drop and bulk temperature. The effects on the efficiency of the heat battery are examined by varying geometrical factors such as flow passage clearance, length of a inlet and outlet tank and the length of a latent heat storage vessel. The flow clearance is a very important -factor on the efficiency of a heat battery. As the flow passage clearance becomes narrow, the flow distribution becomes uniform and the bulk temperature increases, however the pressure drop is large. Therefore, optimal flow passage clearance has to be chosen. The present work can be used in optimizing heat battery efficiency.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.12 no.3
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• pp.385-396
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• 1999

In the process of structural design for large-scale structures with several thousands of degrees of freedom, a plethora of structural calculations with large amount of data storage are required to obtain the forces and displacements of the members. However, current computational environment with single microprocessor such as a personal computer or a workstation is not capable of generating a high-level of efficiency in structural analysis and design process for large-scale structures. In this paper, a high-performance parallel computing system interconnected by a network of personal computers is proposed for an efficient structural analysis. Two distributed structural analysis algorithms are developed in the form of distributed or parallel preconditioned conjugate gradient (DPCG) method. To enhance the performance of the developed distributed structural analysis algorithms, the number of communications and the size of data to be communicated are minimized. These algorithms are applied to the structural analyses of three large space structures as well as a 144-story tube-in-tube framed structure.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.2
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• pp.239-246
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• 2016

In recent years, the power demand has been increasing steadily and the occurrence of maximum power demand has been moving from the summer season to the winter season in Korea. And since the control of electric power supply and demand is more important under those situations, a micro-grid system began to emerge as a keyword for the sTable operation of electric power system. A micro-gird power system is composed of various kinds of distributed generators(DG) such as small diesel generator, wind turbine, photo-voltaic generator and energy storage system(ESS). This paper introduces a method to determine the optimal capacities of the distributed generators which are installed in a stand-alone type of microgrid power system based on the fundamental proportion of diesel generator. At first, the fundamental proportion of diesel generator will be determined by changing from 0 to 50 percent. And then we will optimize the capacities of renewable energy resources and ESS according to load patterns. Lastly, after recalculating the capacity of ESS with consideration for SOC constraints, the optimal capacities of distributed generators will be decided.

• Journal of the Society of Disaster Information
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• v.16 no.1
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• pp.79-86
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• 2020

Purpose: In this study, a model was developed to estimate the storage in Cheonan reservoir using images taken by Sentinel-1 satellite. Method: A total of three reservoirs were studied. All three reservoirs are small reservoirs whose water level is being measured. The preprocessing of Sentinel-1 images was done using SNAP distributed by the European Space Agency(ESA), and the storage was estimated by classifying water surface by the threshold classification method. The estimated reservoir area was compared with satellite and drones images taken on the same day. The correlation was derived by comparing the estimated reservoir area with the actual measurement. Results and Conclusions: The storage values estimated by satellite image analysis showed similar values to the actual measurement data. However, because of the underestimation of the reservoir area due to green algae and Epilithic diatom of summer reservoirs and the low resolution of satellite images, it is dificult to detect reservoir area by satellite images less than 10,000㎡.