• The Journal of the Korea Contents Association
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• v.9 no.1
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• pp.475-483
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• 2009

With the development of information communication and network technologies, ubiquitous era that supports various services regardless of places and time has been advancing. The development of such technologies have a great influence on educational environments. As a result, e-learning concepts that learners use learning contents in anywhere and anytime have been proposed. The various learning contents authoring systems that consider the e-learning environments have also been developed. However, since most of the existing authoring systems support only PC environments, they is not suitable for various ubiquitous mobile devices. In this paper, we design and implement a contents authoring system based on learning activities for u-learning environments. Our authoring system significantly improves the efficiency for authoring contents and supports various ubiquitous devices as well as PCs.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.4
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• pp.739-746
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• 2016

The real-time railway safety monitoring and control system is for prevention of safety accidents, and this system adopts DDS (Data Distribution Service) standard based data transmission method to support integrated management of data from existing on-site safety detection devices. In this paper, we introduce the design of DDS-based data specification from on-site signal equipment on the conventional railway. For this, we (1) design UML data model of KRS SG 0062 standard which defines existing data specification, (2) define DDS Topics for DDS transmission and map KRS model to DDS Topic model, (3) suggest data transformation rules and (4) design network control QoS polices. In addition, we analysis actual on-site log data and validate our data specification design. DDS-based data transmission enables data compatibility among on-site devices and the real-time railway safety monitoring and control system, and allows efficient network management for a large amount of data transfer.

• The KIPS Transactions:PartD
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• v.12D no.2 s.98
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• pp.303-308
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• 2005

Generally, the overloaded server problem and the rapidly increased network traffic problem are happened in a center concentrated multimedia digital content service. Recently, a study about the CDN which is a digital content transmission technology to solve these problems are performed actively. In this study, we proposed the SDCDS which improved a process latency time and a security performance on a digital content delivery and management. The goal of the SDCDS is the digital content security and the improvement of the processing time. For that, we have to design the security and the caching method considering the architecture characteristics of the CDN. In the SDCDS, the public key encryption method is designed by considering the architecture characteristics of CDN. And we improved the processing latency time by improved the caching method which uses the grouped caching method on the encrypted DC and the general DC. And in the experiment, we veryfy the performance of the proposed system.

• KIPS Transactions on Computer and Communication Systems
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• v.6 no.4
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• pp.197-202
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• 2017

The remote healthcare monitoring system enables a doctor to diagnose and monitor patient's health problem from a distance. Previous researches have focused on key establishment method between a patient and a particular doctor to solve personal health information disclosure problem in data transmission process. However, when considering a misdiagnosis of doctor, the result of a diagnosis by a many doctors is more reliable. In previous work, in order to select multiple doctors, patient should generate shared key for each chosen doctor and perform many times encryptions. Therefore, in this paper, we propose a secure data transmission protocol for receiving diagnosis from multiple doctors using identity-based proxy re-encryption scheme. In proposed protocol, a patient don't need key management work for session key. Also, monitoring server performs re-encryption process on behalf of patient. So, we can reduce computational burden of patient in previous work.

• 한국정보교육학회:학술대회논문집
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• 2011.01a
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• pp.211-217
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• 2011

Recent IT (information technology) environmental changes, such as emerging social network services or increasing user participation in multimedia environment, have made it necessary for e-learning systems to undergo changes in various ways. Metadata is an agreement for interoperability between different systems. The standardization of metadata for e-learning system has been driven by some domestic and international organizations, but applying diverse environmental changes into the design of e-learning metadata is in dire need. In this paper, we present a methodology for the analysis and design of modeling e-learning metadata and elicit the design requirements, on the basis of the metadata standard KEM 3.0, about the elements that are expected to be needed in future e-learning systems. Based on the requirements from the analysis, we present the three-layer model for classifying the requirements by the importance of metadata elements per Kana Model. An intelligent e-learning system is to be developed based on the proposed modeling design, which we hope to influence the development of an international standard in the future.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.2
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• pp.382-389
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• 2009

As the use of mobile device is popularized, the needs of variable services of WiMAX technique and the importance of security is increasing. There is a problem that can be easily attacked from a malicious attack because the action is achieved connectionlessly between neighbor link establishing procedure and TEK exchange procedure in mobile WiMAX even though typical 1 hop network security technique is adapted to WiMAX for satisfying these security requirement. In this paper, security connected mechanism which safely connects neighbor link establishing procedure of WiMAX and TEK exchange procedure additional to the basic function provided by IEEE 802.16e standard to satisfy security requirement of mobile WiMAX is proposed. The proposed mechanism strengthens the function of security about SS and BS by application random number and private value which generated by SS and BS to public key of neighbor link establishing procedure and TEK exchange procedure. Also, we can prevent from inside attack like man-in-the-middle which can occur in the request of TEK through cryptographic connection of neighbor link establishing procedure and TEK exchange procedure.

• Journal of the Korea Convergence Society
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• v.9 no.5
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• pp.27-32
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• 2018

IoT technology is developing with various application areas in $4^{th}$ Industrial revolution. There are many users using the application services. Sensing data from various environment need to be transferred to cloud computing storage and store in the cloud storage. However, physical distance from the end node to cloud computing storage is far away, and it is not efficient to transfer data from sensors and store the sensing data in the cloud storage whenever sensing data happen. Therefore, Fog computing is proposed to solve these problems which can process and store the sensing data. However, Fog computing is new emerging technology, there is no standard security model and requirements. This research proposes to security requirements and security model for Fog computing to establish a secure and efficient cloud computing environment.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.38 no.4
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• pp.39-49
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• 2001

Application of information system to hospital would bring innovative improvement on efficiency of business management and provide high quality services toward patients as well as the retrenchment of operating funds. PACS(Picture Archiving and Communication System) including X-ray film that manages the medical image information effectively, has drawn considerable attention to essential structural elements to the sophisticated information system for hospital. PACS system should be connected to the network after making a form of standard medical image file from different style of image information obtained from various medical instruments. In this paper, to solve this problem, we construct Mini-PACS that converts the form of Non-DICOM file to the form of standard file by designing the DICOM converter. This system is designed to be managed under Web environment. Comparing with the existed Mini-PACSs, consisting of the client and server module, our system is designed and implemented with integration of these functions in order to be strongly combine strongly between system.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.4 no.1
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• pp.67-88
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• 2009

The purpose of this study IS to suggest the failure factors and the success factors of technology-based startups(TBS). This study surveyed 327 startup companys on the general obstacles of starting business and the entrepreneurship policy of the Government. The failure factors of TBS are 1) overconfidence of TBS in their technology, 2) lack of cost management, 3) lack of concentration on the sales revenue of their activies, 5) many unplanned challenges, and 5) lack of strategic decision. And the success factors of TBS are 1) CEO's leadership having a clear business concept, 2) development of innovative products and services, 3) flat and flexible organization structure, 4) leveraging outside business resources and networks, and 5) strengthening the human resources by the hybrid agent.

• The Journal of Society for e-Business Studies
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• v.24 no.4
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• pp.135-149
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• 2019

Accounts receivable insurance is a system in which small and medium-sized enterprises insure the accounts receivables acquired by the purchasing company, and the insurance company pays when the purchaser fails to pay the debts. Accounts receivable insurance is a very effective means of eliminating the risk of loss due to the counterparty default, and it is economically effective to protect the domestic industry by preventing the bankruptcy of one company leading to a chain bankruptcy of other companies. In this study, we constructed a business model of the accounts receivable insurance, by building an infrastructure based on a private blockchain in activating the accounts receivable insurance accounts. The accounts receivable insurance platform using these blockchain technologies not only addressed the problem of document and reliability verification for insurance, but also sought ways to facilitate accounts receivable insurance by small businesses through rapid transaction rates, easy network expansion and access management based on private blockchain.