• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.735-737
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• 2017

An Off grid or remote solar electric systems are an energy supply to our home or to our companies without the utility of Grid at all. Off grid solar systems are very important for those who live in remote locations especially for developing countries where getting the electric grid is extremely expensive, inconvenient or for those who doesn't need to pay a monthly bill with the electric bill in general. The main critical components of any solar power system or renewable energy harvesting systems are the energy storage systems and its charge controller system. Energy storage systems are the essential integral part of a solar energy harvesting system and in general for all renewable energy harvesting systems. To provide an optimal solution of both high power density and high energy density at the same time we have to use hybrid energy storage systems (HESS), that combine two or more energy storage technologies with complementary characteristics. In this present work, design and simulation we use two storage systems supercapacitor for high power density and lithium based battery for high energy density. Here the system incorporates fast-response supercapacitors to provide power to manage solar smoothing and uses a battery for load shifting. On this paper discuss that the total energy throughout of the battery is much reduced and the typical thermal stresses caused by high discharge rate responses are mitigated by integrating supercapacitors with the battery storage system. In addition of the above discussion the off grid solar electric energy harvesting presented in this research paper includes battery and supercapacitor management system, MPPT (maximum power point tracking) system and back/boost convertors. On this present work the entire model of off grid electric energy harvesting system and all other functional blocks of that system is implemented in MATLAB Simulink.

• KIISE Transactions on Computing Practices
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• v.22 no.3
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• pp.151-156
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• 2016

Cloud computing systems require a huge number of storage servers due to the growing implications of power bills, carbon emissions, and logistics of data centers. These considerations have motivated researchers to improve the energy efficiency of storage servers. Most servers use a lot of power irrespective of the amount of computing that they are doing, and one important goal is to redesign servers to be power-proportional. However, Research on large-scale storage systems is hampered by their cost. It is therefore desirable to develop a scalable test-bed for evaluating the power consumption of large-scale storage systems. We are building on open-source projects to construct a test-bed which will contribute to the assessment of power consumption in tiered storage systems. Integrating the cloud application platform can easily extend the proposed testbed laying a foundation for the design and evaluation of low-power storage servers.

• Journal of The Korean Society of Agricultural Engineers
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• v.64 no.6
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• pp.43-53
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• 2022

Rice paddy has been actively converted into upland crop fields as more profitable upland crop cultivation are encouraged along with the decrease in rice consumption. However, the current water supply system remains mainly for paddy water supply, so research on pipeline water supply for upland cultivation is needed. The objective of this study was to optimize storage tank installation locations for pipeline water supply in reservoir irrigation districts. Five of reservoir irrigation districts were selected as the study sites and gridded of 10×10 m in size. Then genetic algorithm was adopted to evaluate the effects of spatial storage tank allocation on total pipeline cost. The lengths of the main and branch pipelines were considered as the objective cost function for the optimization of storage tank installation. Overall the shorter the branch pipeline and the longer the main pipeline, as the number of storage tanks increase. The minimal pipeline cost, i.e., optimal condition was reached when approximately 10% of the storage tank numbers to total upland plots were installed. The methodology presented in this study can be applied to determine the number and spatial arrangement of storage tanks for upland pipeline irrigation system design.

• Journal of the Korean Society of Systems Engineering
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• v.19 no.2
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• pp.59-73
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• 2023

Due to the steady growth of the online shopping market and contact-free consumption, the volume of parcels in South Korea continues to increase. However, there is a lack of manpower for delivery workers to handle the growing parcel volume, leading to frequent accidents related to delivery work. As a result, the government and local authorities strive to enhance last-mile logistics efficiency. As one of these measures, unmanned parcel storage lockers are installed and utilized to handle last-mile deliveries. However, the existing parcel storage involves the inconvenience of couriers having to put each parcel in each locker, and this is somewhat insufficient to relieve the workload of delivery workers. In this study, we propose parcel storage devices that use active loading technology to minimize the workload of delivery workers, extract operation risk factors to apply this system to actual sites, and establish risk reduction methods based on the ALARP concept. Through this study, we have laid the groundwork for improving the safety of the system by identifying and proposing mitigation measures for the risk factors associated with the proposed parcel storage devices utilizing active loading technology. When applied in practical settings in the future, this foundation will contribute to the development of a more efficient and secure system. By applying the ALARP concept, a systems engineering technique used in this research, to the development and maintenance of storage devices leveraging active loading technology, it is thought to make the development process more systematic and structured. Furthermore, through the risk management of the proposed system, it is anticipated that a systematic approach to quality management can be employed to minimize defects and provide a stable system. This is expected to be more useful than the existing unmanned parcel storage devices.

• Transactions of the Society of Information Storage Systems
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• v.3 no.2
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• pp.94-112
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• 2007

Nano-sized inverted domain dots in ferroelectric materials have potential application in ultrahigh-density rewritable data storage systems. Herein, a data storage system is presented based on scanning non-linear dielectric microscopy and a thin film of ferroelectric single-crystal lithium tantalite. Through domain engineering, we succeeded to form an smallest artificial nano-domain single dot of 5.1 nm in diameter and artificial nano-domain dot-array with a memory density of 10.1 Tbit/$inch^2$ and a bit spacing of 8.0 nm, representing the highest memory density for rewritable data storage reported to date. Sub-nanosecond (500psec) domain switching speed also has been achieved. Next, long term retention characteristic of data with inverted domain dots is investigated by conducting heat treatment test. Obtained life time of inverted dot with the radius of 50nm was 16.9 years at $80^{\circ}C$. Finally, actual information storage with low bit error and high memory density was performed. A bit error ratio of less than $1\times10^{-4}$ was achieved at an areal density of 258 Gbit/inch2. Moreover, actual information storage is demonstrated at a density of 1 Tbit/$inch^2$.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.29 no.8
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• pp.429-436
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• 2017

There are three main methods to store heat energy; sensible heat storage, latent heat storage, and thermochemical heat storage. Thermochemical heat storage has the highest storage density among the three methods, so this study focused on the thermochemical heat storage method. Experiments were conducted in this study with Zeolite 13x as thermochemical material in a large-scale reactor with 8 kg of Zeolite 13x. Experiments analyzed storage density of Zeolite 13x with respect to four different heating temperatures ($50^{\circ}C$, $100^{\circ}C$, $150^{\circ}C$, $200^{\circ}C$) in heat storage process. As a result, they showed 40~50 percent of storage efficiency in the experiment. Experiments also revealed that reactions between Zeolite 13x and water vapor were reversible and stable, but efficiency of the system was low, compared with sensible heat storage systems or latent heat storage systems.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.1
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• pp.155-164
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• 2015

Information dispersal algorithm guarantees high availability and confidentiality for data and is one of the useful solutions for faulty and untrusted dispersed storage systems such as cloud storages. As the amount of data stored in storage systems increases, data deduplication which allows to save IT resources is now being considered as the most promising technology. Hence, it is necessary to study on an information dispersal algorithm that supports data deduplication. In this paper, we propose an information dispersal algorithm and proof of ownership for client-side data deduplication in the dispersed storage systems. The proposed solutions allow to save the network bandwidth as well as the storage space while giving robust security guarantee against untrusted storage servers and malicious clients.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.3
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• pp.301-312
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• 1999

Experiments were carried out to evaluate performance of the cold air distribution systems with an ice storage tank in test room. Cold air distribution systems provide primary air for comfort conditioning or process cooling at coil discharge temperatures$4^{\circ}C$ to$11^{\circ}C$. The application of a cold air distribution system allows for the downsizing of air distribution equipment and central plant equipment when ice storage tank is used. The benefit of a cold air distribution system include a decrease in the floor-to-floor height, increase floor space, reduced building capital costs, reduced energy use and demand. The use of cold air distribution can result in the most cost effective system and is currently being implemented world wise as the new standard in air conditioning systems. In this study, the cold air distribution system is compared with the general ice storage system. Under the same cooling load conditions, experimental results show that the supply air volume of cold air distribution system decrease 38%, and decrease 45% flow rate of brine for the general ice storage system.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1993.10a
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• pp.922-931
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• 1993

Boundary element method was used to solve heat conduction problem for predicting temperature distribution in grain storage bin. Temperature of grain in storage is one of the three main abiotic factors, besides the intergranular gas composition and the grain moisture content, that determine the keeping quality and control measures used to protect grain from insects and damaging microflora. Collecting the temperature data at various points in the storage bins at different time of the day over a period of time is one way of finding the temperature distribution, this method requires a lot of time, cost and labour and less efficient. However data so collected serve useful purpose of being used to validate predicted temperature distribution using mathematical models. Mathematical models based on physical principles can potentially predict with accuracy the temperature distribution in a grain storage bin. Using the boundary element model the effect of bin wall material, ambient emperature, bin size etc. on temperature distribution can be studied. A knowledge of temperature distribution in stored grain not only helps in identifying active deterioration , but also gives an indication of potential for detection.

• Proceedings of the KIEE Conference
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• 1997.07f
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• pp.1924-1926
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• 1997

With the development of power electronics, many new energy storage systems such as the superconducting magnetic energy storage, the flywheel energy storage, and the capacitive energy storage, etc. are being intensively studied recently in order to replace battery in some special applications, Among these innovative energy storage systems, the flywheel system exhibits some unique features such as high power density, easy maintenance and longer lifetime. This paper introduces the novel flywheel energy storage system. Operation and features of the system are illustrated and verified on a 6kVA, 20kHz IPM based experimental circuit for O/A application. The Halbach Array Motor is selected of the design of the three phase motor/generator for the flywheel energy storage system.