• Journal of the Institute of Electronics Engineers of Korea CI
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• v.47 no.2
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• pp.29-38
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• 2010

Network Video Recorder becomes popular as a next generation surveillance system connecting all cameras and video server in network environment because it can provide ease of installation and efficient management and maintenance. But in case of data damage, the storage device in traditional NVR has no recovery scheme and it is disabled in processing real-time requests. In this paper, we propose an Reliable Storage using Parity and Mirroring scheme for improving reliability on storage device and maintaining system on realtime. RSPM uses a Liberation coding to recover damaged multimedia data and dynamic mirroring to repair corrupted system data and to maintain real-time operation. RSPM using the Liberation code is 11.29% lesser than traditional file system and 5.21% less than RSPM using parity code in terms of loss rate of damaged multimedia data.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.4
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• pp.99-111
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• 2018

Service areas in expressways are very important facilities in terms of efficient expressway operation and the convenience of users. It needs a traffic management strategy to inform drivers in advance about congestion in service areas so as to distribute users of service areas. But due to the lack of sensors and data on numbers of people in the service areas, congestion in service areas had not been measured and managed appropriately. In this study, a congestion index for service areas was developed using telecommunication floating population big data. Two alternative indices (i.e., density of service areas and floating population V/c of service areas) were developed. Finally, the floating population V/c of service areas was selected as a congestion index for service areas for reasons of the ease of understanding and comparison.

• Journal of the Korea Convergence Society
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• v.2 no.1
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• pp.37-44
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• 2011

In accordance with the analysis results on the questionnaires about the awareness of employees according to positions and educational backgrounds in a public health organization, this thesis suggests the basic data on the purpose of the efficient operation and improvement of working environment in a public health organization. Two answers of the questions that "there is a possibility for promotion in the organization" and "the unit section in organization which I work for has a well-designed structure of organization" showed respectively high points in the questionnaire. On the other hand, three questions like there is a resonable way to bind the organization up, completed mission and rewards are connected, and my salary is fit for the current mission showed high points among the questions about the awareness on the organization according to the positions.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.49 no.8
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• pp.84-97
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• 2012

In wireless sensor networks, cluster structure brings on many advantages such as load balancing, energy saving, and distributed key management, and so on. To transform a physical network into the cluster structure, sensor nodes should invoke a cluster formation protocol. During the protocol operation, if some nodes are compromised and they do not conform to the protocol, an inconsistency of membership in a cluster happen. This splits the cluster and consequently increases the number of clusters and decreases the number of members in the cluster. In this paper, we propose a scheme which well copes with such a problem. First, our scheme generates two hop clusters where hop distance between any two nodes is at most two. Besides, our scheme employs verification of two hop distant nodes to prevent the cluster split induced by compromised nodes. Last, our scheme mainly employs broadcast transmissions to reduce energy consumption of nodes. Simulation results have proven that our scheme reduces the number of clusters and more secure and energy-efficient than other scheme.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.9
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• pp.1057-1063
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• 2014

Concerning $CO_2$ reduction from International Societies, lots of laboratories and relevant societies suggest many reports on how to reduce fuel consumption from their specific ways. Undoubtedly, cutting costs is the final desired destination for owner outcome, but many questions there are on the way yet: how is this measure working? how efficient is it? On what size of ship would it work best and be the most effective? etc. Fuel cost is one of the major cost elements for ship owners and/or operators. And by reducing fuel consumption owners and/or operators will reduce both their costs and the environmental impact from their ship. This paper is aim to address how the measures work for saving fuel consumption through improve propulsion efficiency, installation cost and benefit can be calculated easily in the return on investment for estimated one year operation, and finally their compatibility with other fuel saving measure devices.

• Journal of the Korea Society of Computer and Information
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• v.25 no.11
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• pp.139-146
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• 2020

Cloud computing technology provides economic and efficient system operation and management features to deal with rapidly changing IT technologies. However, this is less used in institutes and companies due to low security of cloud computing service. It is recognized that storing and managing important information, which is confidential in external systems is vulnerable to security threats. In order to enhance security of this cloud computing service, this paper suggests a system and user authentication reinforcement model. The suggested technology guarantees integrity of user authentication information and provides users with convenience by creating blocks for each cloud service and connecting service blocks with chains. The block chain user authentication model offers integrity assurance technology of block chains and system access convenience for SSO users. Even when a server providing cloud computing is invaded, this prevents chained invasions not to affect other systems.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.5
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• pp.95-102
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• 2014

In this paper, we propose the high speed PLC-based automatic control system for a smart LED streetlight. The proposed the automatic control system were constructed of a power line modem part and monitoring part, streetlight controller part for the high speed communication frequency band and streetlight ballasts characterization and real-time remote control using a high-speed PLC network, and it was designed to meet to lighting grades conditions of KS road lighting standards. The proposed automatic control system were easy monitoring of the power consumption using PC through to the comparison result of the existing streetlight system. As a result, it was confirmed to the possibility of efficient operation for the real-time monitoring and maintenance by induction of reasonable power consumption through to the LED streetlight state checking and remote-control. In addition, we proved to improvement of expected effects for the power cost savings, the energy efficiency, and streetlight differentiation and advanced.

• The Journal of Korean Association of Computer Education
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• v.11 no.5
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• pp.77-88
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• 2008

Having observed the restriction of the current Web technology, the semantic Web has been developed, and it now has grown up with the core help of the W3C to a level where it recommends the OWL Web ontology language. Besides, in order to deduce the information out of OWL data, several inference systems have been developed such as Jena, Jess, and JTP. Unfortunately, however, quite few systems can effectively handle recently developed OWL data, and further, due to the limitation of file-based operation, the current inference systems cannot meet the requirements for handing huge OWL data. An efficient method for storing and searching ontology data is essential for ensuring stable information inference processes. In this study, firstly, we proposed a model based on the database management system to transform and store OWL data and to enable deduction process from the database. Secondly, we designed and implemented an effective OWL storing system based on our model. Finally, we compare our system with the previous inference systems through experimental performance analysis.

• Journal of KIISE:Computer Systems and Theory
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• v.27 no.6
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• pp.583-591
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• 2000

Caching mechanisms have been studied extensively to buffer the speed gap of hierarchical storages in the context of cache memory, paging system, and buffer management system. As the wide-area distributed environments such as the WWW extend broadly, caching of remote objects becomes more and more important. In the wide-area distributed environments, the cost and the benefit of caching an object is not uniform due to the location of the object; which should be considered in the cache replacement algorithms. For online operation, the time complexity of the replacement algorithm should not be excessive. To date, most replacement algorithms for the wide-area distributed environments do not meet both the non-uniformity of objects and the time complexity constraint. This paper proposes a replacement algorithm which considers the non-uniformity of objects properly; it also allows for an efficient implementation. Trace-driven simulations show that proposed algorithm outperforms existing replacement algorithms.

• The KIPS Transactions:PartD
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• v.13D no.2 s.105
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• pp.223-234
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• 2006

Branching and merging have been being the outstanding methods for SCM in terms of supporting parallel developments. Since well-known commercial merging tools based on textual merging have not detecting semantics conflicts, they can cause semantic errors in the result of merging. Although a lot of researches for detecting semantic conflict and merging up to recently, these researches have been doing individually. Therefore, it is necessary for a research detecting semantic conflict on textual merging and solving it. In this paper, we propose a new method for merging which preserve semantics on textual merging. The method merging two revisions from a source program is as follows : 1) defining changing operations, which include Update, Delete, and Insert operation, per line on two revisions corresponding to the line in source program, 2) detecting textual conflicts and semantic conflict in terms of executional behaviors, 3) solving these conflicts before merging. So, the proposed method can be regarded as a hybrid method that combines a method of textual merging and a behavioral semantic merging.