• Journal of KIISE:Computing Practices and Letters
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• v.15 no.7
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• pp.515-519
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• 2009

As the application fields of sensor nodes are getting diverse these days, it is required to have a way of collecting various data that is suitable for these application fields. In the case that the real-time surveillance over the data is unnecessary, present data collecting methods, which collect and transfer the data directly, can cause a waste of energy and data loss, A new method that store the collected data in a local storage and acquire them by query later on is required for nonreal-time applications. NAND flash has energy efficiency and large capacity so it is suitable for sensor nodes, Sensor nodes support 4-10 KBytes small sized memory and it is hard to build an effective file system since NAND Flash doesn't support overwriting NAND flash. This paper discusses an implementation of NAND Flash file system in sensor node environments. The file system makes long-term data collecting possible by reducing transmission cost. It is expected that this file system will play a central role in sensor network environments as it can be applied to various fields which call for long term data collecting.

• IMMUNE NETWORK
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• v.12 no.1
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• pp.18-26
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• 2012

Background: Vitamin C is an essential nutrient for maintaining human life. Vitamin C insufficiency in the plasma is closely related with the development of scurvy. However, in vivo kinetics of vitamin C regarding its storage and consumption is still largely unknown. Methods: We used $Gulo^{-/-}$ mice, which cannot synthesize vitamin C like human. Vitamin C level in plasma and organs from $Gulo^{-/-}$ mice was examined, and it compared with the level of wild-type mice during 5 weeks. Results: The significant weight loss of $Gulo^{-/-}$ mice was shown at 3 weeks after vitamin C withdrawal. However, there was no differences between wild-type and vitamin C-supplemented $Gulo^{-/-}$ mice (3.3 g/L in drinking water). The concentration of vitamin C in plasma and organs was significantly decreased at 1 week after vitamin C withdrawal. Vitamin C is preferentially deposited in adrenal gland, lymph node, lung, and brain. There were no significant changes in the numbers and CD4/CD8 ratio of splenocytes in $Gulo^{-/-}$ mice with vitamin C withdrawal for 4 weeks. And the architecture of spleen in $Gulo^{-/-}$ mice was disrupted at 5 weeks after vitamin C withdrawal. Conclusion: The vitamin C level of $Gulo^{-/-}$ mice was considerably decreased from 1 week after vitamin C withdrawal. Vitamin C is preferentially stored in some organs such as brain, adrenal gland and lung.

• Journal of the Korea Computer Graphics Society
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• v.17 no.1
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• pp.39-44
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• 2011

In this paper, we introduce a novel method to reduce image to a small size, such that the quality of the image is improved when it is up-scaled. Recent hardwares including cameras and display devices allow us to capture and display high-resolution images. However, it is not always realistic to store and transmit those high-resolution images due to limitation of storage and network bandwidth. Therefore, high-resolution images are often down-scaled to be stored and transmitted, and then up-scaled back for display. To improve final image quality in this scenario, we first formulate selected up-scale methods as linear transformations. The optimal reduction methods are obtained as its inverse transformation. Based on this basic idea, we develop down-scale kernel that is optimized for each up-scale method. In our experiment, the proposed method could improve the quality of the up-scaled image noticeable.

• Journal of Digital Convergence
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• v.13 no.6
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• pp.29-37
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• 2015

Entering the convergence education era, the emergence of smart devices removed the constraint of time and space for study, so if we use smart devices appropriately for education, it will strengthen students' abilities and cultivate creative human resource. Therefore the current study analyzed the general application condition of the smart devices through surveys targeted to students and proposed a measure in applying the smart device as an educational information. In relation to information application, a test was proceeded after carrying out education targeted to experiment group students by naming the group information search, communication, cooperation, sharing, report generation, data storage, online assessment and project management activity. Through the test and survey analysis, it was discovered that the experiment group students displayed higher self-efficacy and ability in applying the smart device as information compared to the control group.

• Journal of Internet Computing and Services
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• v.11 no.6
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• pp.87-110
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• 2010

Recently competitive Korean companies are suffered from financial loss due to illegal exposure of their own proprietary know-how secrets, since it is difficult to watch hidden illegal channels to leak them due to their digitalization. Today the DRM-based system designed to protect such secrets is insufficient to prevent it, since DRM-based protection system cannot defend the intelligent robbery of secrets, in special, employee's robbery. The MSEC is much appropriate to secure secrets against employee's robbery. Our paper notes that IGMP, MSEC and SNMP can work easily together to realize secure system that satisfy strong security condition for prevention from leaking secrets. Since the previous research was on the architectural design for prevention of illegal exposure, this paper proposes the efficient protocol based on MSEC protocol. Our protocol satisfies the strong security conditions that the principles that the secret should be stored/distributed only in an encrypted shape, and should be separated physically from its encryption key, and should be carried in registered mobile storage separate from its processing device, and should be verified in terms of both user and device. Thus this paper proposes both the protocol for secret document distribution and its group key management.

• Water for future
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• v.15 no.3
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• pp.37-47
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• 1982

In the past, the design flow of the urban storm drainage systems has been used largely on a basis of empirical and experience, and the rational formula one of empirical method has been widely used for our country, as well as world wide. But the empirical method has insufficient factor because minimal consideration is given to the relationship of the parameters in the equation to the processes being considered, and considerable use of experience and judgment in setting values to the coefficients in the equation is made. The postcomputer era of hydrology has brought an acceleration development of mathematical methods, thus mathematical models are methods which will greatly increase our understanding in hydrology. On this study, a simple mathematical model of urban presented by British Road Research Laboratory is tested on urban watersheds in Ju An Ju Gong Apartment. The basin is located in Kan Seog Dong, Inchon. The model produces a runoff hydrograph by applying rain all to only the directly connected impervious area of the basin. To apply this model the basin is divided into contributing areas or subbasins. With this information the time area for contributing is derived. The rainfall hyetograph to design storm for the basin flow has been obtained by determination of total rainfall and the temporal distribution of that rainfall determined on the basis of Huff's method form historical rainfall data of the basin. The inflows from several subbaisns are successively routed down the network of reaches from the upstream end to the outlet. A simple storage routing technique is used which involves the use of the Manning equation to compute the stage discharge curve for the cross-section in question. To apply the model to a basin, the pattern of impervious areas must be known in detail, as well as the slopes and sizes of all surface and subsurface drains.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.4
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• pp.1009-1016
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• 2015

In this paper, we propose EPCM(Efficient Prediction-based Context-awareness Matrix) algorithm analyzing connectivity by predicting cluster's context data such as velocity and direction. In the existing DTN, unrestricted relay node selection causes an increase of delay and packet loss. The overhead is occurred by limited storage and capability. Therefore, we propose the EPCM algorithm analyzing predicted context data using context matrix and adaptive revision weight, and selecting relay node by considering connectivity between cluster and base station. The proposed algorithm saves context data to the context matrix and analyzes context according to variation and predicts context data after revision from adaptive revision weight. From the simulation results, the EPCM algorithm provides the high packet delivery ratio by selecting relay node according to predicted context data matrix.

• Journal of KIISE:Information Networking
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• v.30 no.2
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• pp.179-188
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• 2003

Advances in wireless networking technology has engendered a new paradigm of computing, called mobile computing, in which users carrying portable devices have access to a shared infrastructure independent of their physical locations. Wireless communication has some restraints such as disconnection, low bandwidth, a variation of available bandwidth, network heterogeneity, security risk, small storage, and low power. Power adaptation routing scheme overcome the shortage of power by adjusting the output power, was proposed. Existing power saving routing algorithm has some minor effect such as seceding from shortest path to minimize the power consumption, and number of nodes that Participate in routing than optimal because it select a next node with considering only consuming power. This paper supplements the weak point in the existing power saving routing algorithm as considering the gradual approach to final destination and the number of optimal nodes that participate in routing.

• The Journal of the Korea Contents Association
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• v.10 no.7
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• pp.88-97
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• 2010

Recently the more convenient services are provided to people in the city in line with the change of city paradigm and the recent development of ubiquitous. For example, Information on bus arrivals an effective advertisement the combination of high technology and departures through smart-phones. However, in respect of the mobile advertisement, because of difficulties such as the means of transferring the mass storage data or the burden of communication charges. there need means to improve such difficulties. This study has been conducted aiming to overcome such difficulties. This study suggests the strategic differentiation plan through the analysis of the media characteristics such as real time service information when in traveling, U-Bus business model in the category of mobile advertisement, etc. and also the concrete system establishment plan from the operation center via network to the delivery of the advertisement through vehicle terminals. In respect that this study suggests the implications as a practical business model through the fusion of high technology and diverse media. It has great significance.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.3 no.2
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• pp.135-148
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• 2005

In the stage of conceptual design for the construction and operation of the geologic repository for radioactive wastes, it is important to consider a repository ventilation system which serves the repository working environment, hygiene & safety of the public at large, and will allow safe maintenance like moisture content elimination in repository for the duration of the repositories life, construction/operation/closure, also allowing safe waste transportation and emplacement. This paper describes the possible ventilation system design criteria and requirements for the prospective Korean radioactive waste repositories with emphasis on the underground rock cavity disposal method in the both cases of low & medium-level and high-level wastes. It was found that the most important concept is separate ventilation systems for the construction (development) and waste emplacement (storage) activities. In addition, ventilation network system modeling, natural ventilation, ventilation monitoring systems & real time ventilation simulation, and fire simulation & emergency system in the repository are briefly discussed.