• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.1
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• pp.257-264
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• 2012

The development of mobile devices and the spread of wireless network help share and exchange information and resources more easily. The bond them to Cloud Computing technology help pay attention to "Mobile Cloud" service, so there have been being a lot of studies on "Mobile Cloud" service. Especially, the important of 'Recommendation Service' which is customized for each user's preference and context has been increasing. In order to provide appropriate recommendation services, it enables to recognize user's current state, analyze the user's profile like user's tendency and preference, and draw the service answering the user's request. Most existing frameworks, however, are not very suitable for mobile devices because they were proposed on the web-based. And other context information except location information among user's context information are not much considered. Therefore, this paper proposed the context-aware framework, which provides more suitable services by using user's context and profile.

• Journal of the Korean Data and Information Science Society
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• v.23 no.1
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• pp.171-177
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• 2012

Various phenomenon can be expressed numerically and collected as a data due to rapid development of the computer. In particular large set of data is collected in various fields. We can obtain the information for final decision based on analysis and interpretation of the data. The issue is the management of the data as well as the importance of the data. So a system which stores the data in server and prints out the data to web browser is demanded. We uploaded the file of Excel form to server database and developed a web based program which can show the uploaded data through web based database. We used the Oracle DB for uploading and web programming language such as html, JAVA, JSP for querying the data. Finally, we developed a program for web based clinical data management system construction.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.4
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• pp.374-380
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• 2015

With explosion of wireless traffic it is required to further investigate the technologies on acquiring available spectrum resources and on sharing frequency with existing users. In 3GPP, it is started to study on feasibility and functional requirement of LTE standard in order to extend cellular services offered on only licensed band to 5 GHz unlicensed band. Operating scenario on LTE in unlicensed band is focused on carrier aggregation with licensed band, and the coexistence with Wi-Fi services in 5 GHz band is concerned as a major requirement. For a single global solution framework for licensed assisted access to unlicensed spectrum, listen-before-talk(LBT) mechanism of European regulation for fair access to channel under the coexistence environments is currently examined in 3GPP. In this paper, we evaluate two types of LBT, frame based equipment and load based equipment, with considering LTE carrier aggregation feature and performances of file transferred time and throughput.

• Progress in Medical Physics
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• v.23 no.4
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• pp.239-251
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• 2012

In this paper, web-base image processing system has been implemented for remote-controlled medical robot applications. The developed software system was hierarchically composed of diverse image processing and remote operation modules, and the hierarchical composition was satisfied the expandability to higher level application and the accessibility over the web. It can also support diverse file formats including DICOM, VRML, and CAD(STL) to display, transmit, store and share the processed images depending on application environment. Message-based data exchange, object-oriented module and open-source based software configuration will enable the dynamic combination associated with diverse remote medical application requirements.

• The Journal of Information Systems
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• v.15 no.1
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• pp.1-20
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• 2006

Peer-to-peer systems (P2P) are rapidly growing in importance on the Internet environment, quickly extending the range of their usage. However, peer-to-peer systems have not been widely applied in electronic commerce because they have not been established as an appropriate business model. Therefore, we firstly review the previous research relevant to peer-to-peer systems, and then analyze the business models for P2P systems presented by previous researchers. Furthermore, this study categorizes major issues in terms of the technical and business model aspects. On the basis of these reviews, we develop P2P electronic commerce systems based on the file sharing method between users, focusing on user interface friendliness. A developed P2P electronic commerce systems are programmed by using the C# based on the Microsoft.net solution. A database is implemented using the MSSQL2000. A main application technology is designed that P2P electronic commerce systems make it possible. for user to extend into BtoB Solution by using WSDL (Web Services Description Language), UDDI (Universal Description, Discovery, and Integration) and the XML that is a document for users. User interface is made as form of Internet messenger for a user's convenience and is possible to develop into a commodity transaction system based on XML. In this study, it is possible for the P2P electronic commerce system to have extended application to fields such as Internet shopping mall and property transaction in a nonprofit organization, a public institution and a large scale nonprofit institution that have a similar structure as compared with a structure of a nonprofit educational institution.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.9A
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• pp.1359-1367
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• 2000

A new coherent detection scheme with data based channel estimation (DBCE) for CDMA/BP(staggered burst pilot in parallel) channel structure is proposed. Because the pilot burst initiates DBCE operation periodically it is shown to be remarkably stable to Gaussian noise and Doppler shift with proper parameter settings. In our own system parameter setting, there is a negligible loss(0.068 dB) in $E_{b}/N_{o}$ by the introduction of the burst pilot. When compared with an ideal coherent detection, the required $E_{b}/N_{o}$ on Doppler shift corresponding to the speed of 160Km/H is degraded less that 2.0 dB. the burst pilot can be implemented without complexity even though some extra correlators are needed for DBCE. This improvement is superior to the previously coherent CDMA detectors with external or internal pilot.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.30 no.3
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• pp.397-403
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• 2020

With the convenience of real-time conversation, multimedia file and contact sharing services, most people use instant messenger, and its usage time is increasing. Because the messengers contain a lot of user behavior information data, in the digital forensic investigation, they can be very useful evidence to identify user behavior. However, some of useful data can be difficult to acquire or recognize because they are encrypted or deleted. Thus, in order to use the messenger data as evidence, the study of message decryption process and message recovery is essential. In this paper, we analyze the database encryption process of the instant messenger, MalangMalang Talkafe, and propose the method to decrypt it. In addition, we propose the methods to identify the deleted messages and recover from the volatile memory area.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.2
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• pp.178-188
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• 2016

The traffic in the wired and wireless networks has increased exponentially because of increase of smart phone and improvement of PC performance. Multimedia services and file transmission such as Facebook, Youtube occupy a large part of the traffic. CDN is a technique that duplicates the contents on a remote web server of content provider to local CDN servers near clients and chooses the optimal CDN server for providing the content to the client in the event of a content request. In this paper, the content request message between CDN servers and the client used the SCRP algorithm utilizing the MST algorithm and the traffic throughput was optimized. The average response time for the content request is reduced by employing HC_LRU cache algorithm that improves the cache hit ratio. The proposed SCRP and HC_LRU algorithm may build a scalable content delivery network system that efficiently utilizes network resources, achieves traffic localization and prevents bottlenecks.

• Journal of Information Management
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• v.32 no.1
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• pp.108-119
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• 2001

Creating digital document by scanning paper or using a digital camera or using a computer is a daily task at every office. Digital document is increasing at high pace. The quantity of digital document is almost beyond the maximum capacity of the online storage and is destroying searching efficiency. To solve these problems, we developed a document management system(ChronoStar) by integrating various searching methods(Picture, Full-Text Related), 3D graphic and a DVD changer.

• Smart Media Journal
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• v.5 no.1
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• pp.114-121
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• 2016

Currently, different medical institutions have been carrying out the e-healthcare system project. The system includes electronic medical record and prescription delivery system, and, the Medical Treatment law permits electronic signature for medical record management, which reduced the relevant costs and enabled sharing medical record. And medical solution using online certificates is expanding its application. In that light, the role of certificates became more important than ever. However, in contrast to active effort made to manage personal certificates, certificates related to medical solutions and other types of work are not being managed properly. Most work-related certificates are saved in office computers, which makes them vulnerable to various security threats. Although certificate servers can be used as a solution to this problem, hospitals must build the server separately and, therefore, small and medium-size hospitals can be reluctant to bear the burden. This study proposed a way to design and implement an effective and secure certificate management system by save the certificate file as a BLOB, using existing resources without needing to build a separate certificate server, at minimized costs.