• Journal of Navigation and Port Research
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• v.40 no.6
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• pp.385-390
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• 2016

ELoran Systems can provide Position, Navigation, and Time services with comparable performance to Global Positioning Systems (GPS) as a back up or alternative system. High timing and navigation performance can be achieved by eLoran signals because eLoran receivers use "all-in-view" reception. This incorporates Time of Arrival (TOA) signals from all stations in the service range because each eLoran station is synchronized to Coordinated Universal Time (UTC). Transmission station information and the differential Loran correction data are transmitted via an additional Loran Data Channel (LDC) on the transmitted eLoran signal such that eLoran provides improved Position Navigation and Timing (PNT) over legacy Loran. In this paper, we propose a technique for adapting the delay time compensation values in eLoran timing receivers to provide precise time comparison. For this purpose, we have designed a system that measures time delay from the crossing point of the third cycle extracted from the current transformer at the end point of the transmitter. The receiver delay was measured by connecting an active H-field, an E-field and a passive loop antenna to a commercial eLoran timing receiver. The common-view time transfer technique using the calibrated eLoran timing receiver improved the eLoran transfer time. A eLoran timing receiver calibrated by this method can be utilized in the field for precise time comparison as a GNSS backup.

• Korean Journal of Agricultural and Forest Meteorology
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• v.21 no.4
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• pp.347-357
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• 2019

The usefulness of processing and analysis systems of GIS-based agricultural climate data is affected by the reliability and availability of computing infrastructures such as cloud, on-premises, and hybrid. Cloud technology has grown in popularity. However, various reference cases accumulated over the years of operational experiences point out important features that make on-premises technology compatible with cloud technology. Both cloud and on-premises technologies have their advantages and disadvantages in terms of operational time and cost, reliability, and security depending on cases of applications. In this study, we have described characteristics of four general computing platforms including cloud, on-premises with hardware-level virtualization, on-premises with operating system-level virtualization and hybrid environments, and compared them in terms of advantages and disadvantages when a huge amount of GIS-based agricultural climate data were stored and processed to provide public services of agro-meteorological and climate information at high spatial and temporal resolutions. It was found that migrating high-resolution agricultural climate data to public cloud would not be reasonable due to high cost for storing a large amount data that may be of no use in the future. Therefore, we recommended hybrid systems that the on-premises and the cloud environments are combined for data storage and backup systems that incur a major cost, and data analysis, processing and presentation that need operational flexibility, respectively.

• Journal of KIISE:Information Networking
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• v.29 no.4
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• pp.412-427
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• 2002

This paper proposes a restoration scheme based on mobility learning and prediction in the presence of the failure of mobility databases in mobile communication systems. In mobile communication systems, mobility databases must maintain the current location information of users to provide a fast connection for them. However, the failure of mobility databases may cause some location information to be lost. As a result, without an explicit restoration procedure, incoming calls to users may be rejected. Therefore, an explicit restoration scheme against the failure of mobility databases is needed to guarantee continuous service availability to users. Introducing mobility learning and prediction into the restoration process allows systems to locate users after a failure of mobility databases. In failure-free operations, the movement patterns of users are learned by a Neuro-Fuzzy Inference System (NFIS). After a failure, an inference process of the NFIS is initiated and the users' future location is predicted. This is used to locate lost users after a failure. This proposal differs from previous approaches using checkpoint because it does not need a backup process nor additional storage space to store checkpoint information. In addition, simulations show that our proposal can reduce the cost needed to restore the location records of lost users after a failure when compared to the checkpointing scheme

• Journal of Food Hygiene and Safety
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• v.27 no.4
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• pp.339-348
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• 2012

The purpose of this study is to predict the economic size of foods-for-elderly market, which will be valuable information for establishing related policy and backup system. After setting the scope of related industry, detailed information for current market situation was investigated and a systematic forecast for market changes in the future was performed. Economic growth, changes in consumer expenditure and economic status of the elderly, current subscription of medical insurance and saving for pension were reflected. In addition, a survey toward related firms was completed and changes in aged population and incidence of chronic disease in the elderly were taken into account. Results show that the annual growth rate of the market was predicted to be the minimum 4.54% through the maximum 8.32% from 2010 to 2025 and its market size was forecasted to be the minimum 7,073 ten million won through the maximum 10,976 ten million won. It is expected that the market of foods-for-elderly will grow rapidly with development of foods technology and fast increase of aged population. Especially, growth of health functional foods and foods for special dietary uses for elderly will be distinguished. However, it seems that related firms are on the hedge, watching current trend of the related industry. This may results in insufficient supply against the demand. Therefore, policy for foods-for-elderly should be introduced and systematically administered, including R&D support, standardization and authentication for foods-for-elderly, construction of related database system.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.4
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• pp.117-123
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• 2013

In the recent cloud storage environment, the amount of SSD (Solid-State Drive) replacing with the traditional hard disk drive is increasing. Management of SSD for its space efficiency has become important since SSD provides fast IO performance due to no mechanical movement whereas it has wearable characteristics and does not provide in place update. In order to manage space efficiency of SSD, data de-duplication technique is frequently used. However, this technique occurs much overhead because it consists of data chunking, hasing and hash matching operations. In this paper, we propose new data de-duplication method using PRAM cache. The proposed method uses hierarchical hash tables and LRU(Least Recently Used) for data replacement in PRAM. First hash table in DRAM is used to store hash values of data cached in the PRAM and second hash table in PRAM is used to store hash values of data in SSD storage. The method also enhance data reliability against power failure by maintaining backup of first hash table into PRAM. Experimental results show that average writing frequency and operation time of the proposed method are 44.2% and 38.8% less than those of existing data de-depulication method, respectively, when three workloads are used.

• Journal of the Society of Disaster Information
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• v.16 no.2
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• pp.392-401
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• 2020

Purpose: This study analyzes the operating characteristics of a lithium ion capacitor that can be used as a standby power supply in an emergency, and determines whether the standby power supply is abnormal even by measuring the voltage using a linear proportionality characteristic during charging and discharging. The aim is to provide an experimental basis that can be done. Method: As a method for this study, first, analyze the operation principle and characteristics of the existing backup power supply and lithium ion capacitor, and then measure the voltage of the lithium ion capacitor according to the configuration and system block diagram of the induction lamp used in the experiment. We proceed with the test of the measured value of discharge power for each voltage band to check the amount of power held by the battery and the operation test experiment using induction lamps. Results: Just by checking the charging voltage using the linear proportional characteristics of lithium ion capacitors, it provides a basis for accurately inferring the effective operating time of induction lamp lamps. Conclusion: In the event of a disaster, the lithium ion capacitor is used as a spare power supply for emergency induction lamps to prevent complete discharge of emergency induction lamps, to prevent the problem of performing normal operation of the standby power supply, and to use only a simple voltage measurement to reserve power. It was intended to suggest many uses for evacuation equipment application in the future by making it possible to check whether the device is abnormal.

• Journal of the korean academy of Pediatric Dentistry
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• v.37 no.2
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• pp.207-212
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• 2010

Protein C deficiency increases the risk of thrombosis due to the lack of anticoagulant factor protein C. Among the numerous congenital protein C deficiencies, homozygous protein C deficiency has an especially low protein C activity level, that it is almost undetectable. It is a rare disease with a probability of 1:250000~500000. The signs and symptoms of homozygous protein C deficiency include purpuric, necrotic dermatosis, ecchymosis, blindness, and thrombosis in central nervous system. A 4-year-old girl was brought to the clinic with a chief complaint of extensive caries. The child was under warfarin medication in order to prevent possible complications during dental treatment. We consulted the pediatric department. Without warfarin intake, serious complications may occur due to thrombosis during dental treatment. Therefore, certain warfarin dosage (INR 3~5) and fresh frozen plasma as a backup for excessive hemorrhage were recommended. This child was a severely disabled child with the loss of vision, and it was difficult to manage her behavior effectively. Thus, dental treatment was carried out under general anesthesia, where bleeding control would be also easier to achieve.This report presents the case of a 4-year-old girl with protein C deficiency, who has received dental treatment for extensive caries under general anesthesia.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.7B
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• pp.605-619
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• 2003

The main memory DBMS(MMDBMS) efficiently supports various database applications that require high performance since it employs main memory rather than disk as a primary storage. In this paper, we discuss the index manager of the Tachyon, a next-generation MMDBMS. Recently, the gap between the CPU processing and main memory access times is becoming much wider due to rapid advance of CPU technology. By devising data structures and algorithms that utilize the behavior of the cache in CPU, we are able to enhance the overall performance of MMDBMSs considerably. In this paper, we address the practical implementation issues and our solutions for them obtained in developing the cache-conscious index manager of the Tachyon. The main issues touched are (1) consideration of the cache behavior, (2) compact representation of the index entry and the index node, (3) support of variable-length keys, (4) support of multiple-attribute keys, (5) support of duplicated keys, (6) definition of the system catalog for indexes, (7) definition of external APIs, (8) concurrency control, and (9) backup and recovery. We also show the effectiveness of our approach through extensive experiments.

• Journal of Science and Technology Studies
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• v.18 no.1
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• pp.219-265
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• 2018

Recently, interest in energy tranisition is rising. Energy transition requires active participation and cooperation of diverse stakeholders, including users / citizens, in that it requires not only changes in technological factors but also changes and coordination of various social factors. Living labs are attracting attention as one of the ways to do this. This article is a detailed analysis of the activities of the mini-PV living lab in the urban area from 2016 to 2017 at the Seoul, Sung Dae Goal. Through the Living Lab, mini PV DIY products, backup centers, local financial services, and the development of a variety of education and training strategies have been achieved. These activities and achievements were analyzed through questions raised on strategic, tactical, and operational levels, as well as through multi-level perspective and interaction between initiative, regime, and niche. In conclusion, this living lab activity confirmed the possibility of a 'transition lap' to solve social problems such as sustainability of energy production and utilization. In particular, it gained remarkable results in terms of the operational leves of transition management governance, that is, transition experiment, and it was also remarkable in that it was the initiative of citizens. However, it did not proceed without difficulty. In particular, structural problems such as the conflict between the flexibility inherent in living lab and the bureaucratic rigidity of the financial support organization have appeared. There was also a limitation that there was no 'transition field' on the strategic level necessary to replicate and expand strategic niches while spreading the knowledge gained from the transition experiment, forming the vision of transition.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.22 no.4
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• pp.827-839
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• 2012

A cell phone is very close to the user and therefore should be considered in digital forensic investigation. Recently, the proportion of smartphone owners is increasing dramatically. Unlike the feature phone, users can utilize various mobile application in smartphone because it has high-performance operating system (e.g., Android, iOS). As acquisition and analysis of user data in smartphone are more important in digital forensic purposes, smartphone forensics has been studied actively. There are two way to do smartphone forensics. The first way is to extract user's data using the backup and debugging function of smartphones. The second way is to get root permission, and acquire the image of flash memory. And then, it is possible to reconstruct the filesystem, such as YAFFS, EXT, RFS, HFS+ and analyze it. However, this methods are not suitable to recovery and analyze deleted data from smartphones. This paper introduces analysis techniques for fragmented flash memory pages in smartphones. Especially, this paper demonstrates analysis techniques on the image that reconstruction of filesystem is impossible because the spare area of flash memory pages does not exist and the pages in unallocated area of filesystem.