• Aerospace Engineering and Technology
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• v.13 no.2
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• pp.54-59
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• 2014

This paper cites about a test & analysis support set to support a testing and analysis of CFDP(CCSDS File Delivery Protocol) that processes commands and data as a series of file for reliable deep space communication. And this paper includes a basic description of CFDP and an objective and functions of CFDP-TASS(CFDP - Test Analysis & Support Set). CFDP-TASS is an equipment to examine OBC(On-Board Computer) CFDP in normal and abnormal cases, gather all packets in test, and support to analyze effectively the result of tests.

• Journal of information and communication convergence engineering
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• v.22 no.2
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• pp.121-126
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• 2024

In enterprise environments, file owners are often required to share critical files with other users, with encryption-based file delivery systems used to maintain confidentiality. However, important information might be leaked if the cryptokey used for encryption is exposed. To recover confidentiality, the file owner must then re-encrypt and redistribute the file along with its new encryption key, which requires considerable resources. To address this, we propose a key management server that minimizes the distribution of encryption keys when critical files are compromised, with unique encryption keys assigned for each registered user to access critical files. While providing the targeted functions, the server employs a level of system resources comparable to that of legacy digital rights management. Thus, when implemented in an enterprise environment, the proposed server minimizes cryptokey redistribution while maintaining accessibility to critical files in the event of an information breach.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.7
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• pp.612-622
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• 2013

In this paper, we propose a coding packet group-based ARQ scheme (rNC) for file delivery in wireless networks. rNC assumes multiple network coding points between the source and the destination. Each network coding point gathers and codes a group of packets according to the queue polling system. A queue polling system makes a few or several packets available for coding in a queue while polling the other queues in the system. Thus, we assuem a queue polling system at each network coding point. We call this group of packets as coded packet group. Each coding point acknowledges the reception of every code packet group to its previous coding point for reliable delivery. Thus, the intermediate coding points including the source can release its buffer before the packet is delivered to the destination. To guarantee the ultimate file delivery to the destination, the destination sends acknowledgement to the sender. We evaluate our proposed scheme using ns-2 and compare the performance with CodeCast. The results show that rNC works better than CodeCast in terms of packet delivery ratio and control overhead in unreliable wireless networks.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.11
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• pp.2913-2927
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• 2013

A data hiding scheme in HTML files is presented in this paper. Web pages are a very popular medium for broadcasting information and knowledge nowadays, and web pages are a good way to achieve the goal of secret message delivery because the different HTML coding codes will render the same screen in any of the popular browsers. The proposed method utilizes the HTML special space codes and sentence segmentation to conceal secret messages into a HTML file. The experimental results show that the stego HTML file generated by the proposed method is imperceptible. Also, the proposed method can conceal one more secret bit in every between-word location.

• The Journal of Information Technology and Database
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• v.8 no.2
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• pp.41-60
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• 2001

Despite the growth in Internet users, demand for multi-medial, large data files and resulting explosive growth in data traffic, there has been lack of investment in Middle-Mile, interconnection of various networks, resulting in bottleneck effect, which is acerbating. One strategy to overcome such network bottleneck is Content Delivery Network (CDN). CDN does not achieve efficient delivery of large file data through physical improvement/increase in network capacity, but by delivering large file contents, the cause of bottlenecks, from distributed servers. Since it is impracticable to physically improve networks capacity to accommodate the growth in internet traffic, CON, by strong CPs contents at cache servers deployed at major ISPs networks, is able to deliver requested contents to the requesting Web clients without the loss of data and long latency.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.10
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• pp.1397-1402
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• 2021

The overlay2 file system is one of the union file systems that mounts multiple directories into one. The source directory used for this overlay2 file system mount has a characteristic that it operates independently of the write-able layer after mounting, so it is often used for container platforms for application delivery. However, the overlay2 file system has a security vulnerability that the write-able layer is also modified when file in the source directory is modified. In this study, I proposed the overlay2 file system protection technology to remove the security vulnerabilities of the overlay2 file system. As a result of empirically implementing the proposed overlay2 file system protection technology and verifying the function, the protection technology proposed in this study was verified to be effective. However, since the method proposed in this study is a passive protection method, a follow-up study is needed to automatically protect it at the operating system level.

• Journal of Korea Society of Industrial Information Systems
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• v.12 no.4
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• pp.74-88
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• 2007

In order to automate the process of mail sorting by delivery sequence, it is necessary to prepare a postal address database and to interpret written addresses on the mail-pieces with the database and OCR technology. The address database is a critical factor of automation and informatization of postal service since it could be used not only in address recognition but also in various mail processing. In this study, we design the schema of postal address database, design the postal address file based on it and explain the method of address interpretation and retrieval using it. We analyze infonnation requirements for transformation of postal address into the standardized format and consider them in the process of design. The postal address file can be used by address matching or retrieval system as well as by Hangul address recognition system for automation of delivery sequence mail-sorting.

• Aerospace Engineering and Technology
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• v.12 no.2
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• pp.91-98
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• 2013

Computing environment of space explorer including LEO (Low Earth Orbit), GEO (Geosynchronous Earth Orbit) satellite may be considered as the same category of embedded system on the ground. But with comparison with personal computing environment it is widely accepted that the space computing is outdated and behind of state of the art. Especially file system which is nearly essential item in all ground computing environment including personal computer, workstation and server is rarely used in space explorer till lately. In this paper, a study of ESA PUS (Packet Utilization Standard) and CCSDS (Consultative Committee for Space Data Systems) community's activity, international trend, and applicable technical application for applying file system in oder to use these standards for utilizing the file system to deep space explorer is described.

• Progress in Medical Physics
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• v.30 no.4
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• pp.128-138
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• 2019

Purpose: Segmental analysis of volumetric modulated arc therapy (VMAT) is not clinically used for compositional error source evaluation. Instead, dose verification is routinely used for plan-specific quality assurance (QA). While this approach identifies the resultant error, it does not specify which machine parameter was responsible for the error. In this research study, we adopted an approach for the segmental analysis of VMAT as a part of machine QA of linear accelerator (LINAC). Methods: Two portal dose QA plans were generated for VMAT QA: a) for full arc and b) for the arc, which was segmented in 12 subsegments. We investigated the multileaf collimator (MLC) position and dosimetric accuracy in the full and segmented arc delivery schemes. A MATLAB program was used to calculate the MLC position error from the data in the dynalog file. The Gamma passing rate (GPR) and the measured to planned dose difference (DD) in each pixel of the electronic portal imaging device was the measurement for dosimetric accuracy. The eclipse treatment planning system and a MATLAB program were used to calculate the dosimetric accuracy. Results: The maximum root-mean-square error of the MLC positions were <1 mm. The GPR was within the range of 98%-99.7% and was similar in both types of VMAT delivery. In general, the DD was <5 calibration units in both full arcs. A similar DD distribution was found for continuous arc and segmented arcs sums. Exceedingly high DD were not observed in any of the arc segment delivery schemes. The LINAC performance was acceptable regarding the execution of the VMAT QA plan. Conclusions: The segmental analysis proposed in this study is expected to be useful for the prediction of the delivery of the VMAT in relation to the gantry angle. We thus recommend the use of segmental analysis of VMAT as part of the regular QA.

• Journal of Korean Society on Water Environment
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• v.25 no.3
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• pp.375-385
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• 2009

The estimation of delivery ratio is a essential part of Korean Total Maximum Daily Loads (TMDL) procedure which needs a number of observed stream flow and pollutants data. If observed data were not sufficient, researchers have to find other alternatives. One of them is to make indirect data by using watershed models, such as Soil and Water Assessment Tool (SWAT) and Hydrological Simulation Program - FORTRAN (HSPF) and so on. In this study, indirect daily data was made by using SWAT model. To build the Byongseong-SWAT model accurately, crop cultures are reflected by handling the MGT.file in SWAT model. Especially, mass of manure and schedule of crop culture are inputted through investigating domestic research papers as well as fieldwork. After calibrating SWAT model in comparison with the 22-years flow and pollutants observed outlet data, the delivery ratio of Byongseong watershed is calculated by using daily simulated data during 2004-2007. Empirical equations for delivery ratio through multi-regression analysis are developed by using meteorological and physical factors such as flow, watershed area, stream length, catchment slope, curve number (CN) and subbasin's pollutant discharge loads.