• Journal of Wetlands Research
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• v.19 no.1
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• pp.45-51
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• 2017

Nepal is a landlocked mountainous country in South Asia, located between China to the north and India to the south, east, and west. As such, wastewater management has become one of the most significant problems in urban area of Nepal. In Nepal, the centralized wastewater treatment systems were dysfunctional due to high cost of operation, discontinuous power supply, lack of proper maintenance and proper technical workforce to address the issues. As such, constructed wetlands (CW) were applied to treat various secondary wastewater as alternative to wastewater treatment facilities. Generally, efficiency and sustainability of CW technology depends on proper operation and maintenance and active community involvement. This study summarizes information about 26 CW in Nepal. Specifically, factors including data banking, removal efficiency, quality of discharged water, compliance to water quality standard of Nepal and operation and maintenance were investigated. Considering removal efficiency per pollutant, Ka-1 achieved the greatest reduction for most pollutant followed by B-1, L-3, Ka-5 and K-1. Nepal has practiced CW technology for more than 2 decades but currently, development of technology was interrupted by the inefficient performance of existing facilities. Public awareness about the technology, natural disaster, unavailability of specified substrate materials, lack of fund for further research and experiments has hindered the expansion of technology. In spite of these concerns, CW was still proven as an alternative solution to the present wastewater problems in urban areas of Nepal.

• Korean Journal of Construction Engineering and Management
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• v.8 no.1 s.35
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• pp.66-77
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• 2007

With the electricity industry structure reformation of the government in April, 2001, Korea Power Electric Corporation was divided in to Korea water power nuclear power and 5 thermal power plant. After, various delivery method is introduced and applied for active profit creation according to the competition between each development companies for the public company privatization. However, the current situation does not satisfy the project participant by selecting the delivery method without reflecting the business goal and project characteristics of power plant construction business. The objective of this study is to research the influencing factors that should be considered to select the delivery method in thermal power construction business and develop a standard of selection of appropriate delivery method through questionnaire and interviews to establish a model to select the delivery method that fits the business goal of the subject of delivery. In the future, if the delivery method selection model suggested in this study is applied, it is expected to select the appropriate delivery method of power plant construction business by effectively reflecting the business goal, characteristics and demand of the delivery subject, and characteristics of the construction business apart from the existing customary practices that decided the delivery method dependent on the subjective and experience based judgement.

• Korean Journal of Agricultural and Forest Meteorology
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• v.8 no.1
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• pp.36-44
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• 2006

In this study, we constructed a forest fire danger map in the Yeongdong area of Gangwon-do and Northeastern area of Gyeongsangbuk-do using a forest fire rating model and geographical information system (GIS). We investigated the appropriate positions of the automatic weather station (AWS) and a comprehensive network solution (a system including measurement, communication and data processing) for the establishment of an optimum mountain meteorological observation network system (MMONS). Also, we suggested a possible plan for combining the MMONS with unmanned monitoring camera systems and wireless relay towers operated by local governments and the Korea Forest Service for prevention of forest fire.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.3
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• pp.41-50
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• 2009

The flash memory has many advantages such as low power consumption, strong shock resistance, fast I/O and non-volatility. And it is increasingly used in the mobile storage device. Many researchers are studying the YAFFS, NAND flash file system, which is widely used in the embedded device. However, the existing YAFFS has two problems. First, it takes long time to mount the YAFFS file system because it scans whole spare areas in all pages. Second, the cleaning policy of the YAFFS does not consider the wear-leveling so that it cannot guarantee the duration of data completely. In order to solve these problems, this paper proposes a new content-based YAFFS that consists of a mounting time reduction technique and a content-cleaning policy by using content-based block management. The proposed method only scans partial spare areas of some special pages and provides the block swapping which enables the wear-leveling of data blocks. We performed experiments to compare the performance of the proposed method with those of the JFFS2 system and YAFFS system. Experimental results show that the proposed method reduces the average mounting time by 82.2% comparing with JFFS2 and 42.9% comparing with YAFFS. Besides, it increases the life time of the flash memory by 35% comparing with the existing YAFFS whereas no overheat is added.

• Journal of Internet Computing and Services
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• v.15 no.4
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• pp.125-133
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• 2014

The column-oriented database storage is a very advanced model for large-volume data analysis systems because of its superior I/O performance. Traditional data storages exploit row-oriented storage where the attributes of a record are placed contiguously in hard disk for fast write operations. However, for search-mostly datawarehouse systems, column-oriented storage has become a more proper model because of its superior read performance. Recently, solid state drive using MLC flash memory is largely recognized as the preferred storage media for high-speed data analysis systems. The features of non-volatility, low power consumption, and fast access time for read operations are sufficient grounds to support flash memory as major storage components of modern database servers. However, we need to improve traditional transaction management scheme due to the relatively slow characteristics of column compression and flash operation as compared to RAM memory. In this research, we propose a new scheme called Column-aware Multi-Version Locking (CaMVL) scheme for efficient transaction processing. CaMVL improves transaction performance by using compression lock and multi version reads for efficiently handling slow flash write/erase operation in lock management process. We also propose a simulation model to show the performance of CaMVL. Based on the results of the performance evaluation, we conclude that CaMVL scheme outperforms the traditional scheme.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.15 no.2
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• pp.151-159
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• 2017

A deep geological disposal at a depth of 500 m in stable host rock is considered to be the safest method with current technologies for disposal of spent fuels classified as high-level radioactive waste. The most important requirement is that the temperature of the bentonite buffer, which is a component of the engineered barrier, should not exceed $100^{\circ}C$. In Korea, the amount of spent fuel generated by nuclear power generation, which accounts for about 30% of the total electricity, is continuously increasing and accumulating. Accordingly, the area required to dispose of it is also increasing. In this study, various duplex disposal concepts were derived for the purpose of improving the disposal efficiency by reducing the disposal area. Based on these concepts, thermal analyses were carried out to confirm whether the critical disposal system requirements were met, and the thermal stability of the disposal system was evaluated by analyzing the results. The results showed that upward 75 m or downward 75 m apart from the reference disposal system location of 500 m depth would qualify for the double layered disposal concept. The results of this study can be applied to the establishment of spent fuel management policy and the design of practical commercial disposal system. Detailed analyses with data of a real disposal site are necessary.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.381-385
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• 2010

An aging Society solitary life old mans are increasing. The nurses have to visit old mans and must confirm their disease, because they do not act well. It is very difficult to take care old man, because the number of Nurses are small. This problem is solved by collection of data about condition of old mans from long distance. Data communication with Ethernet have benefit to collection of measurement of old man's condition. The Data storage system an long distance place are storaged data and after several day data was transmitted to the DB over the Ethernet. For Miniaturization of such system the system must be OS-less Embedded Ethernet Server system. Such system manages the file management system only with H/W. The Storage device is used SD-card. SD Card is small size and operates with small power. By using 512MB sd memory card, it is possible to storage during 5~6 years, 10 byte of temperature value per second. In this paper, we make a Embedded Ethernet Server using W3100A, Atmega128 MCU and data stroage device using SD-Card. This system operates with O/S-less Embedded Ethernet Server. We talk about file System, Storage and Ethernet. We explained about MCU Atmega128, Interface between LAN LSIand W3100A, Interface between W3100A and Phyceiver RTL8201, data I/O between MCU and SD-Card and File System. We shows the experiment device and result of monitoring.

• The KIPS Transactions:PartA
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• v.9A no.4
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• pp.399-404
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• 2002

Along the evolution of information and communication technologies, manufacturing embedded systems such as PDA (personal digital assistant), HPC (hand -held PC), settop box. and information appliance became realistic. And RTOS (real-time operating system) and filesystem have been played essential re]os within the embedded systems as well. For the filesystem of embedded systems, flash memory has been used extensively instead of traditional hard disk drives because of embedded system's requirements like portability, fast access time, and low power consumption. Other than these requirements, nonvolatile storage characteristic of flash memory is another reason for wide adoption in industry. However, there are some technical challenges to cope with to use the flash memory as an indispensable component of the embedded systems. These would be relatively slow cleaning time and the limited number of times to write-and-clean. In this paper, a new cleaning policy is proposed to overcome the problems mentioned above and relevant performance comparison results will be provided. Ranking cleaning policy(RCP) decides when and where to clean within the flash memory considering the cost of cleaning and the number of times of cleaning. This method will maximize not only the lifetime of flash memory but also the performance of access time and manageability. As a result of performance comparison, RCP has showed about 10 ~ 50% of performance evolution compared to traditional policies, Greedy and Cost-benefit methods, by write throughputs.

• Journal of Advanced Navigation Technology
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• v.27 no.6
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• pp.835-840
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• 2023

RFID(Radio Frequency Identification) systems are attracting attention as a key component of Internet of Things technology due to the cost and energy efficiency of application services. In order to use RFID technology in the IoT application service field, it is necessary to be able to store and manage various information for a long period of time as well as simple recognition between the reader and tag of the RFID system. And in order to read and write information to tags, a performance improvement technology that is strong and reliable in poor wireless channels is needed. In particular, in the UHF(Ultra High Frequency) RFID system, since multiple tags communicate passively in a crowded environment, it is essential to improve the recognition rate and transmission speed of individual tags. In this paper, Middleton's Class A impulsive noise model was selected to analyze the performance of the RFID system in an impulsive noise environment, and FM0 encoding and Miller encoding were applied to the tag to analyze the error rate performance of the RFID system. As a result of analyzing the performance of the RFID system in Middleton's Class A impulsive noise channel, it was found that the larger the Gaussian noise to impulsive noise power ratio and the impulsive noise index, the more similar the characteristics to the Gaussian noise channel.

• The Journal of the Korea Contents Association
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• v.9 no.8
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• pp.64-72
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• 2009

AMR(Automatic Meter Reading), which means that it reads the meter of electricity, gas, or water, etc at a remote place automatically through wired or wireless communication, has been studied in terms of Power Line Communication method and Local Area Wireless Communication method, etc. In this paper, we designed and implemented JCA(Java Card for AMR) capable of AMR, which is based on java Card technology indispensable to the ubiquitous world. In this paper, JCA follows standard transactional procedures offered by power supply company and manages power usage log and billing data, and is designed in order to satisfy EMV multi-functional specifications. Because JCA is a multi-functional smart card capable of post-issuance applets as an open platform, it is installed into other applications of affiliated concerns as well as credit card and traffic card applications. Not only the proposed JCA is a low cost system, compared to other AMR systems, but is capable of paying rates in advance or later by applying authentication and security function of java Card. In addition the proposed JCA system can create value added services such as affiliated services with corporate alliance.