• KIPS Transactions on Computer and Communication Systems
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• v.12 no.11
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• pp.319-328
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• 2023

Unlike cloud computing, edge computing technology analyzes and judges data close to devices and users, providing advantages such as real-time service, sensitive data protection, and reduced network traffic. EdgeX Foundry, a representative open source of edge computing platforms, is an open source-based edge middleware platform that provides services between various devices and IT systems in the real world. EdgeX Foundry provides a service for handling camera devices, along with a service for handling existing sensed data, which only supports simple streaming and camera device management and does not store or process image data obtained from the device inside EdgeX. This paper presents a technique that can store and process image data inside EdgeX by applying some of the services provided by EdgeX Foundry. Based on the proposed technique, a service pipeline for object detection services used core in the field of autonomous driving was created for experiments and performance evaluation, and then compared and analyzed with existing methods.

• Journal of KIISE
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• v.44 no.11
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• pp.1130-1137
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• 2017

The multi-leveling technique that stores multiple bits in a single memory cell has significantly improved the density of NAND flash memory along with shrinking processes. However, because of the side effects of the multi-leveling technique, the average write performance of MLC NAND flash memory is degraded more than twice that of SLC NAND flash memory. In this paper, we introduce existing cross-layer optimization techniques proposed to improve the performance of MLC NAND flash-based storages, and propose a new integration technique that overcomes the limitations of existing techniques by exploiting their complementarity. By fully exploiting the performance asymmetry in MLC NAND flash devices at the flash translation layer, the proposed technique can handle many write requests with the performance of SLC NAND flash devices, thus significantly improving the performance of NAND flash-based storages. Experimental results show that the proposed technique improves performance 39% on average over individual techniques.

• Korean Journal of Food Science and Technology
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• v.16 no.1
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• pp.95-98
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• 1984

A pilot scale continuous Kimchi pasteurizer was used to study some factors affecting the retardation of acidification of Chinese radish Kimchi, stored at $20^{\circ}C$. The degrees of acidification of Kimchi were measured in terms of pH, acidity and absorbance. The shelf-life of the pasteurization temperature from 60 to $70^{\circ}C$ did not result in any significant effect on delaying the acidification of Kimchi during storage, while lowering of storage temperature from 25 to $5^{\circ}C$ gave rise to a marked increase in the the shelf-life of Kimchi.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.12C
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• pp.1014-1020
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• 2008

Storage devices such as memories are widely used in various electronic products. They require high-density memory and currently the data has been stored in multi-level format, that results in high error rate. In this paper, we apply error correction schemes that are widely used in communication system to the storage devices for satisfying low bit error rate and high code rate. In A WGN channel with average BER $10^{-5}$ and $5{\times}10^{-6}$, we study error correction schemes for 4-1evel cell to achieve target code rate 0.99 and target BER $10^{-11}$ and $10^{-13}$, respectively. Since block codes may perform better than the concatenated codes for high code rate, and it is important to use less degraded inner code even when many bits are punctured. The performance of concatenated codes using general feedforward systematic convolutional codes are worse than the block code only scheme. The simulation results show that RSC codes must be used as inner codes to achieve good performance of punctured convolutional codes for high code rate.

• Journal of KIISE:Databases
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• v.32 no.1
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• pp.1-11
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• 2005

An aggregation query computes aggregate information over a data cube in the query range specified by a user Existing methods based on the prefix-sum approach use an additional cube called the prefix-sum cube(PC), to store the cumulative sums of data, causing a high space overhead. This space overhead not only leads to extra costs for storage devices, but also causes additional propagations of updates and longer access time on physical devices. In this paper, we propose a new prefix-sum cube called 'SPEC' which drastically reduces the space of the PC in a large data warehouse. The SPEC decreases the update propagation caused by the dependency between values in cells of the PC. We develop an effective algorithm which finds dense sub-cubes from a large data cube. We perform an extensive experiment with respect to various dimensions of the data cube and query sizes, and examine the effectiveness and performance ot our proposed method. Experimental results show that the SPEC significantly reduces the space of the PC while maintaining a reasonable query performance.

• Journal of Korean Tunnelling and Underground Space Association
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• v.25 no.2
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• pp.175-186
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• 2023

The buffer materials in disposal hole are exposed to the decay heat from spent nuclear fuels and groundwater inflow through adjacent rockmass. Since understanding of thermal-hydro-mechanical-chemical (T-H-M-C) interaction in buffer material is crucial for predicting their long-term performance and safety of disposal repository, it is necessary to investigate the heating-hydration characteristics and consequent T-H-M-C behavior of the buffer materials under disposal conditions considering geochemical factors. In response, the Korea Atomic Energy Research Institute developed a laboratory-scale 'Lab.THMC' experiment system, which characterizes the T-H-M behavior of buffer materials under different geochemical conditions by analyzing heating-hydration process and stress changes. This technical report introduces the detail design of the Lab.THMC system, summarizes preliminary experimental results, and outlines future research plans.

• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.3
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• pp.241-247
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• 2005

This paper deals with the operation of a flywheel energy storage UPS. The UPS has good features such as long life-time, improved efficiency, no environmental problems, reduced size and space, and low maintenance cost compared with the conventional UPS using battery. The operating principle of the UPS is analysed in each mode including voltage compensation as well as uninterruptible power supply. Especially, the tracking characteristic of the disturbed phase of the source voltage after outage is analysed. The usefulness of the system is proved through simulations and experiments.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.1
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• pp.77-82
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• 2014

SD memory cards are widely used in portable digital devices, and most of them exploit NAND flash memory as their storage, so that they have a feature of storing users' important data safely with low costs. In case of using NAND flash memory as storage, however, there is no method to store users' data if memory capacity is insufficient when transferring a large volume of data. This paper proposes a virtual SD memory card system. It used a SD memory card device driver to process data requested from a host by exploiting external storage rather than by exploiting flash memory as a memory core for storing data to the SD memory card. For experiment, it used the FPGA-based SD card slave controller IP on the SMC controller with a S3C2450 ARM CPU to test.

• Journal of Digital Contents Society
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• v.16 no.4
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• pp.535-543
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• 2015

Recently, NAND flash based storage devices are being used as a storage device in various fields through hiding the limitations of NAND flash memory and maximizing the advantages. In particular, those storage devices contain a software layer called Flash Translation Layer(FTL) to hide the "erase-before-write" characteristics of NAND flash memory. FTL includes the metadata for managing the data requested from host. That metadata is stored in internal memory because metadata is very frequently accessed data for processing the requests from host. Thus, if the power-loss occurs, all data in memory is lost. So metadata management scheme is necessary to store the metadata periodically and to load the metadata in the initialization step. Therefore we proposed the scheme which satisfies the core requirements for metadata management and efficient operation. And we verified the efficiency of proposed scheme by experiments.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.4
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• pp.781-792
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• 2015

This paper proposes a virtual and invisible private disk (VIPDISK) technology equipped with the secure storage devices. As a software based security technology, it can create hidden partitions on any data storage device which can not be identified by the windows OS, so the program running on it, does not have any evidence of the existence of the hidden storage space. Under inactive state, it maintains an unexposed secure partition which can only be activated with a matching combination of a unique digital key and a user password to open the decryption tool. In addition, VIPDISK can store data to secure storage device with real-time encryption, it is worry-free even in the case of lost or theft. Simulation results show that VIPDISK provides a much higher level of security compared to other existing schemes.