• Proceedings of the Korean Environmental Sciences Society Conference
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• 2003.11a
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• pp.73-78
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• 2003

In this research, we implement Realtime Air Diffusion Prediction System which is a parallel Fortran model running on distributed-memory parallel computers. The system is designed for air diffusion simulations with four-dimensional data assimilation. For regional air quality forecasting a series of dynamic downscaling technique is adopted using the NCAR/Penn. State MM5 model which is an atmospheric model. The realtime initial data have been provided daily from the KMA (Korean Meteorological Administration) global spectral model output. It takes huge resources of computation to get 24 hour air quality forecast with this four step dynamic downscaling (27km, 9km, 3km, and lkm). Parallel implementation of the realtime system is imperative to achieve increased throughput since the realtime system have to be performed which correct timing behavior and the sequential code requires a large amount of CPU time for typical simulations. The parallel system uses MPI (Message Passing Interface), a standard library to support high-level routines for message passing. We validate the parallel model by comparing it with the sequential model. For realtime running, we implement a cluster computer which is a distributed-memory parallel computer that links high-performance PCs with high-speed interconnection networks. We use 32 2-CPU nodes and a Myrinet network for the cluster. Since cluster computers more cost effective than conventional distributed parallel computers, we can build a dedicated realtime computer. The system also includes web based Gill (Graphic User Interface) for convenient system management and performance monitoring so that end-users can restart the system easily when the system faults. Performance of the parallel model is analyzed by comparing its execution time with the sequential model, and by calculating communication overhead and load imbalance, which are common problems in parallel processing. Performance analysis is carried out on our cluster which has 32 2-CPU nodes.

• Korean Journal of Occupational Health Nursing
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• v.26 no.4
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• pp.207-217
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• 2017

Purpose: This study aimed to evaluate the workplace response system (WRS) against infectious disasters (IDs) based on the response attitudes and capacity of occupational health nurses (OHNs) who worked during the 2015 Middle East Respiratory Syndrome (MERS) outbreak in South Korea. Methods: Fifty-one participants who had worked as OHNs at the time of the 2015 MERS outbreak were surveyed from November 20 to December 10, 2016. Data were collected using a self-report questionnaire and analyzed using descriptive statistics and McNemaer's test. Results: According to the survey results, the following were lacking in the WRS: a dedicated ID-response team, manuals, related education programs for OHNs, and health education programs for workers. Results also confirmed that workers were vulnerable to new infectious diseases because of the lack of health checkups and support for workers before and after business trips abroad. Among the respondents, 98.0% answered affirmatively that an ID was important for health management in the workplace, but 64.7% answered that it was difficult to manage an ID. The perceived capacity items to respond to IDs ranged from 3.0 points to 3.3 points. This scores were generally high. Conclusion: As the WRS is currently insufficient, it is necessary to develop an adequate WRS to IDs by addressing the identified problems.

• The Journal of the Korea Contents Association
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• v.13 no.2
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• pp.32-43
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• 2013

These days, there are more and more IT research institutions which foresee cloud services as the predominant IT service in the near future and there, in fact, are actual cloud services provided by some IT leading vendors. Regardless of physical location of the service and environment of the system, cloud service can provide users with storage services, usage of data and software. On the other hand, cloud service has challenges as well. Even though cloud service has its edge in terms of the extent to which the IT resource can be freely utilized regardless of the confinement of hardware, the availability is another problem to be solved. Hence, this paper is dedicated to tackle the aforementioned issues; prerequisites of cloud computing for distributed file system, open source based Hadoop distributed file system, in-memory database technology and high availability database system. Also the author tries to body out the high availability mass distributed data management architecture in cloud service's perspective using currently used distributed file system in cloud computing market.

• The Journal of Society for e-Business Studies
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• v.18 no.2
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• pp.1-26
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• 2013

Estimating levels of user trust is important for maintaining continuous use of e-commerce systems because trust alleviates user concerns about the invisibility of service providers or their reputation. Conventional trust estimation approaches such as policy-and reputationbased reasoning have focused on the experience of e-commerce systems at an early stage. However, only a few trust reasoning methods have considered the mature stage, which is more related to continuance intention. We propose a trust reasoning method dedicated to the mature stage of using e-commerce systems. In particular, a new method of unobtrusively estimating the degree of user intimacy is developed, because intimacy has been highly associated with trust as well as reputation. Our experiments show that the proposed method is valid and can be used in conjunction with reputation-based trust reasoning.

• Journal of Information Management
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• v.42 no.4
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• pp.175-194
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• 2011

This study evaluated the fiction collection of Korean public libraries by applying use factor and suggested various measures to enhance collection development function. As a result, while the collection building and borrowing ratios of Korean literature in literature collection by language were the highest at 62.6% and 54.3% respectively, the use factor was lower than the base value(1.00). And while the collection building and borrowing ratios of Korean contemporary fiction by item category were the highest at 65.60% and 51.36% respectively, the use factor was lower than the base value and the use factor by year is decreasing in recent years. The reason is because of poor collection development. Therefore, public library need to consider active alternatives such as establishment of the collection development policy and fiction collection development guideline, composition of the fiction material selection committee, adaption of the dedicated librarian system for fiction material development, development and utilization of a selection tool for fiction materials, and periodic evaluation of fiction collection.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.12
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• pp.6214-6242
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• 2019

Routing in mobile ad hoc networks is performed in a distributed fashion where each node acts as host and router, such that it forwards incoming packets for others without relying on a dedicated router. Nodes are mostly resource constraint and the users are usually inclined to conserve their resources and exhibit selfish behaviour by not contributing in the routing process. The trust and reputation models have been proposed to motivate selfish nodes for cooperation in the packet forwarding process. Nodes having bad trust or reputation are detected and secluded from the network, eventually. However, due to the lack of proper identity management and use of non-persistent identities in ad hoc networks, malicious nodes can pose various threats to these methods. For example, a malicious node can discard the bad reputed identity and enter into the system with another identity afresh, called whitewashing. Similarly, a malicious node may create more than one identity, called Sybil attack, for self-promotion, defame other nodes, and broadcast fake recommendations in the network. These identity-based attacks disrupt the overall detection of the reputation systems. In this paper, we propose a reputation-based scheme that detects selfish nodes and deters identity attacks. We address the issue in such a way that, for normal selfish nodes, it will become no longer advantageous to carry out a whitewash. Sybil attackers are also discouraged (i.e., on a single battery, they may create fewer identities). We design and analyse our rationale via game theory and evaluate our proposed reputation system using NS-2 simulator. The results obtained from the simulation demonstrate that our proposed technique considerably diminishes the throughput and utility of selfish nodes with a single identity and selfish nodes with multiple identities when compared to the benchmark scheme.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.4
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• pp.1481-1500
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• 2016

Device-to-Device (D2D) communication underlaying macro-small cell networks, as one of the promising technologies in the era of 5G, is able to improve spectral efficiency and increase system capacity. In this paper, we model the cross- and co-tier D2D communications in two-tier macro-small cell networks. To avoid the complicated interference for cross-tier D2D, we propose a mode selection scheme with a dedicated resource sharing strategy. For co-tier D2D, we formulate a joint optimization problem of power control and resource reuse with the aim of maximizing the overall outage capacity. To solve this non-convex optimization problem, we devise a heuristic algorithm to obtain a suboptimal solution and reduce the computational complexity. System-level simulations demonstrate the effectiveness of the proposed method, which can provide enhanced system performance and guarantee the quality-of-service (QoS) of all devices in two-tier macro-small cell networks. In addition, our study reveals the high potential of introducing cross- and co-tier D2D in small cell networks: i) cross-tier D2D obtains better performance at low and medium small cell densities than co-tier D2D, and ii) co-tier D2D achieves a steady performance improvement with the increase of small cell density.

• Journal of Digital Convergence
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• v.13 no.9
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• pp.505-513
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• 2015

This study was intended for suggestions enabling sports enterprises to lead the sports industry convergence. The method of study was literature reviews and discussed on improvements of the current law through examining the relevant law and regulations in the future. In the result, the current sports industry is faced with many matters. Despite the convergence availability of sports industry, professional sports industry human resources shortages, the absence of dedicated organizational mechanisms, R&D investment shortage and insufficient legal aspects can be presented. Fostering human resources with expertise and the installation of organization that can support sports industrial convergence are required to solve these problems. In conclusion, since sports industry has a value added area higher than other industries and bring economic ripple effect as a result of convergence activities, a climate for promoting sports convergence enterprises should be created.

• Journal of Digital Convergence
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• v.11 no.7
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• pp.149-155
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• 2013

Recently, automobile traffic systems are evolving toward Intelligent Traffic Systems(ITS) with smart sensor technology and collaboration between traffic systems and external ones. On the contrary, Korean ITS services have little improvement comparing with other communication services. The main causes of this phenomenon are due to already allocation of ITS recommended frequency band to broadcasting services, and also dedication of DSRC frequency band over ISM band resulting in interferences. This paper provides the analysis of current Korean ITS technology status, and two suggestions to activate the ITS industry. First, need to fix the ITS standard combining WAVE and DSRC specifications soon. Second, ITS frequency allocation to complete its standard implementation in near time frame.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.5
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• pp.89-94
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• 2021

Recently, manufacturing companies are introducing many intelligent production processes that apply IIoT/ICT to improve competitiveness, and a system that maintains availability, improves productivity, and optimizes management costs is needed as a preventive measure using environmental data generated from air ejectors. Therefore, in this study, a dedicated control board was developed and LoRa communication module was applied to remotely control it to collect and manage information about compressors from cloud servers and to ensure that all operators and administrators utilize common data in real time. This dramatically reduced M/S steps, increased system operational availability, and reduced local server operational burden. It dramatically reduced maintenance latency by sharing system failure conditions and dramatically improved cost and space problems by providing real-time status detection through wired and mobile utilization by maintenance personnel.