• Journal of KIISE:Databases
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• v.29 no.5
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• pp.347-357
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• 2002

Graphs have provided a powerful methodology to solve a lot of real-world problems, and therefore there have been many proposals on the graph representations and algorithms. But, because most of them considered only memory-based graphs, there are still difficulties to apply them to large-scale problems. To cope with the difficulties, this paper proposes a graph representation and graph algorithms based on the well-developed relational database theory. Graphs are represented in the form of relations which can be visualized as relational tables. Each vertex and edge of a graph is represented as a tuple in the tables. Graph algorithms are also defined in terms of relational algebraic operations such as projection, selection, and join. They can be implemented with the database language such as SQL. We also developed a library of basic graph operations for the management of graphs and the development of graph applications. This database approach provides an efficient methodology to deal with very large- scale graphs, and the graph library supports the development of graph applications. Furthermore, it has many advantages such as the concurrent graph sharing among users by virtue of the capability of database.

• The KIPS Transactions:PartA
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• v.13A no.3 s.100
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• pp.191-198
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• 2006

Today's portable electric consumer devices, which are operated by battery, tend to integrate more multimedia processing capabilities. In the multimedia processing devices, multimedia system-on-chips can handle specific algorithms which need intensive processing capabilities and significant power consumption. As a result, the power-efficiency of multimedia processing devices becomes important increasingly. In this paper, we propose a reconfigurable data caching architecture, in which data allocation is constrained by software support, and evaluate its performance and power efficiency. Comparing with conventional cache architectures, power consumption can be reduced significantly, while miss rate of the proposed architecture is very similar to that of the conventional caches. The reduction of power consumption for the reconfigurable data cache architecture shows 33.2%, 53.3%, and 70.4%, when compared with direct-mapped, 2-way, and 4-way caches respectively.

• Journal of the Korean Society of Safety
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• v.29 no.1
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• pp.47-53
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• 2014

The application of advanced Main Control Room(MCR) is accompanied with lots of changes and different forms and features through the virtue of new digital technologies. The characteristics of these digital technologies and devices give many opportunities to the interface management, and can be integrated into a compact single workstation in advanced MCR so that workers can operate the plant with minimum physical burden under any operation conditions. However, these devices may introduce new types of human errors and thus a means to evaluate and prevent such errors is needed, especially those related to characteristics of digital devices. This paper reviewed the new type of human error hazards of tasks based on digital devices and surveyed researches on physiological assessment related to human error. An experiment was performed to verify human error hazards by physiological responses such as EEG which was measured to evaluate the cognitive workload of operators. And also, the performances of four tasks which are representative in human error hazard tasks based on digital devices were compared. Response time, ${\beta}$ power spectrum rate of each task by EEG, and mental workload by NASA-TLX were evaluated. In the results of the experiment, the rate of the ${\beta}$ power was increased in the task 1 and task 4 which are searching and navigating task and memory task of hierarchical information, respectively. In case of the mental workload, in most of evaluation items, task 1 and 4 were highly rated comparatively. In this paper, human error hazards might be identified by highly cognitive workload. Conclusively, it was concluded that the predictive method which is utilized in this paper and an experimental verification can be used to ensure the safety when applying the digital devices in Nuclear Power Plants (NPPs).

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2004.05b
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• pp.579-582
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• 2004

File share system in client/server method requires server of High performance and capacity and this server is very expensive and management is complex and is been influenced much to flatform. Also, extension of correct memory or hard drive etc. causes a lot of expenses to server. While, may minimise human who happen by buying high-capacity server by dispersing file public ownership way unuse expensive server in client/serve. way who put up files in PC(client) to a sewer and manage files and make use of only client computers because public ownership of data and government official in P2P(peer to peer) environment, waste of material resources. Many people are interested to P2P by such reason, researches that use P2P to connection field to be Moba that have Gakgwangbatgo current are gone vigorously.

• The KIPS Transactions:PartD
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• v.15D no.5
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• pp.609-620
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• 2008

The service handling the map data in the mobile device including navigation, LBS, Telematics, and etc., becomes various. The size of map data which is stored and managed in the mobile device is growing and reaches in several GB. The conventional navigation system has used the read-only PSF (physical storage format) in order to enhance the performance of system by maximum in the mobile device which has limited resources. So though a little part of the map data is changed the whole data must be updated. In general, it takes several ten minutes to write the 2 GB map data to a flash memory of mobile device. Therefore, we have developed the mobile spatial DBMS (database management system) to solve the problem which is that the partial map data couldn't be updated in the conventional navigation system. And we suggest the policy to guarantee the performance of the navigation system which is implemented using the spatial mobile DBMS and verify this by experiment.

• The KIPS Transactions:PartA
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• v.8A no.4
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• pp.429-438
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• 2001

GPS (Global Positioning System) is the most ideal navigation system which can be used on the earth irrespective of time and weather conditions. GPS has been used for various applications such as construction, survey, environment, communication, intelligent vehicles and airplanes and the needs of GPS are increasing in these days. This paper deals with the design and implementation of the RTOS (Real-Time Operating System) for a GPS navigation computer in the GPS/INS integrated navigation system. The RTOS provides the optimal environment for execution and the base platform to develop GPS application programs. The key facilities supplied by the RTOS developed in this paper are priority-based preemptive scheduling policy, dynamic memory management, intelligent interrupt handling, timers and IPC, etc. We also verify the correct operations of all application tasks of the GPS navigation computer on the RTOS and evaluate the performance by measuring the overhead of using the RTOS services.

• Safety and Health at Work
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• v.2 no.2
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• pp.176-182
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• 2011

Objectives: Previous investigations have presented some evidence of late cognitive effects in dental personnel exposed to metallic mercury. We wanted to examine if Norwegian dentists have an increased prevalence of symptoms consistent with neurological and/or cognitive malfunction. Methods: The study group consisted of 406 dentists from central Norway and 217 controls from the general population, all under the age of 70. They had responded to a standardised postal questionnaire (Euroquest) inquiring about seven symptoms in regard to neurology, psychosomatics, memory, concentration, mood, sleep disturbances, and fatigue. A score was calculated for each symptom based on 4 to 15 single questions scored on a scale from 1 (seldom or never) to 4 (very often). Results: The dentists and controls had a participation rate of 57.2 % and 42.9 % respectively. The dentists reported no more cognitive symptoms than the controls, with low average symptom scores from 1.16 for neurological symptoms in males to 1.73 for fatigue in females. Corresponding figures for the controls were 1.22 and 1.77. There were a total of 1.2 % of the dentists and 1.8 % of the controls who reported having three or more of the seven symptoms "often" or more frequently. Conclusion: Norwegian dentists do not report more cognitive and neurological symptoms than controls from the general population.

• Journal of Digital Convergence
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• v.19 no.9
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• pp.463-468
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• 2021

Although the IoT is showing explosive growth due to the development of technology and the spread of IoT devices and activation of services, serious security risks and financial damage are occurring due to the activities of various botnets. Therefore, it is important to accurately and quickly detect the activities of these botnets. As security in the IoT environment has characteristics that require operation with minimum processing performance and memory, in this paper, the minimum characteristics for detection are selected, and KNN (K-Nearest Neighbor), Naïve Bayes, Decision Tree, Random A comparative study was conducted on the performance of machine learning algorithms such as Forest to detect botnet activity. Experimental results using the Bot-IoT dataset showed that KNN can detect DDoS, DoS, and Reconnaissance attacks most effectively and efficiently among the applied machine learning algorithms.

• Journal of dental hygiene science
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• v.19 no.1
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• pp.67-75
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• 2019

Background: Dementia is a condition in which a person who has been living a normal life suffers from various cognitive impairments in memory, words, and judgment that considerably disrupt daily life. The oral care ability and subjective oral status of elderly individuals with dementia are lower than those of a healthy person. The oral health care of individuals admitted to nursing homes inevitably falls to nursing assistants and nursing care staff. This study aimed to investigate the need for oral health management items of and to provide basic direction for the future of the Dementia National Responsibility System. Methods: Elders aged 65 years and over were selected from a comprehensive welfare center. A total of 155 questionnaires were analyzed. The questionnaire consisted of 15 items about general status, 9 items about recognition of the Dementia National Responsibility System, 5 items of the subjective recognition of oral health, and 6 items of the correlation between oral health and dementia. Results: Among our subjects, 71.0% answered that they did not know about the Dementia National Responsibility System, 78.7% answered that they think they need the system, and 81.9% think that they should add dental health items to the Dementia National Responsibility System. The response to the need for dementia national responsibility, oral health items in the Dementia National Responsibility System, and oral specialists all showed scores of >4 points. The need for the Dementia National Responsibility System, oral health items, and specialists were found. Conclusion: It is necessary to include oral health care items in the Dementia National Responsibility System so that elderly individuals with dementia can receive the needed oral health care.

• The Korean Journal of Archival Studies
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• no.59
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• pp.5-46
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• 2019

This study aims to explore the concepts and nature of records in digital environments based on analyzing recent theoretical studies of records. This is not intended to defining records for management in a specific environment. This study is divided into two parts. Firstly, it classifies the definitions of records in three perspectives; evidence, information, and representation of activities, and explores the concepts and theoretical backgrounds underlying each definition. Secondly, it articulates some implications for understanding the concept and nature of records in digital environments by four categories such as i) fixity, ii) materiality, iii) activity and context, and iv) trustworthiness, which were derived from the definition of "persistent representation of activities" by Geoffrey Yeo.