• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.12
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• pp.2305-2309
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• 2016

Cloud Computing Service should support efficiency and stability. United States of America, for example, provides FedRAMP (Federal Risk and Authorization Management Program) accreditation to certify cloud computing service and hence growth of computing service industry is giving benefits of cost reduction and efficiency to companies. However, the use of computing service brings more risk than ever. Because cloud computing holds all the data of multiple companies, problems such as hacking bring out control loss of service and as a result total data of companies can be lost. Unfortunately, cloud computing certification programs do not have any good solutions for this data loss and companies may lose all the important data without any proper data backup. This paper studies such problems in terms of backup problem and provides Data Availability Zone solution for recovery and safe saving of data so that computing service can offer better efficiency and stability.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.04a
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• pp.365-370
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• 1998

The creep strain of the compression zone of concrete beams subjected to cyclic loading should be a significant factor in increasing strain and deflections. An analytical model which is similar to a previous one is presented to predict the increase in cyclic creep strain and the damage using the properties of the constituent materials: concrete and steel. The analytical expressions are compared with our experimental data. The effect of concrete-creep is accounted by the term En, Icr,n, and Mcr,n. In this study, it is proved that cyclic creep exponents 'n' in Cyclic Creep Model, according to the parameters -strength, range of stress- have the various values. It is hoped that with the availability of more experimental data and better understanding of some of the complex behavior, the model could be further improved.

• Journal of The Korean Digital Architecture Interior Association
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• v.9 no.2
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• pp.5-16
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• 2009

The importance of playground, which is a central place in the outdoor space scheme for apartment and in children's outdoor activity, is increasing. The stature and availability in playground may be varied according to connection between playground and outdoor space and to characteristics of outdoor space. The purpose of this study is to arrange basic data in guidelines of a planning for supporting children's development and for activating its use in the apartment housing. This study conducted the field survey and questionnaire research after selecting 4-case apartment complexes based on the relevant preceding research. The survey results are as follows. Children were recognizing and preferring the playground as the central space in outdoor play activity. Mothers were preferring outdoor space adjacent to playground. There were the most responses with saying that a mother takes to play with a child. Children responded that the use of playground and the rides are the outdoor activity that they do the most. And, it was surveyed that there is difference in dweller's using playground by apartment complex according to characteristics of a planning for outdoor space. Given being connected with square with segregation of pedestrian and vehicle and with the resting space, the availability in playground was the highest. The availability in playground, which has high connection with diversely outdoor space elements while having good accessibility to the apartment building, was surveyed to be high. Playground had high preference in case of being connected with waterfront and resting space, rather than green zone. Diverse environmental artifacts and decorative fence may become a visually stimulus source that can activate the use of playground.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.11
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• pp.5323-5343
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• 2018

Mobile applications and social networks tend to enhance the need for high-quality content access. To address the rapid growing demand for data services in mobile networks, it is necessary to develop efficient content caching and distribution techniques, aiming at significantly reduction of redundant content transmission and thus improve content delivery efficiency. In this article, we develop optimal cooperative content cache and distribution policy, where a geographical cluster model is designed for content retrieval across the collaborative small cell base stations (SBSs) and replacement of cache framework. Furthermore, we divide the SBS storage space into two equal parts: the first is local, the other is global content cache. We propose an algorithm to minimize the content caching delay, transmission cost and backhaul bottleneck at the edge of networks. Simulation results indicates that the proposed neighbor SBSs cooperative caching scheme brings a substantial improvement regarding content availability and cache storage capacity at the edge of networks in comparison with the current conventional cache placement approaches.

• The KIPS Transactions:PartC
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• v.18C no.1
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• pp.31-44
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• 2011

The applicability of network-based computing depends on the availability of the underlying network bandwidth. Such a growing gap between the capacity of the backbone network and the end users' needs results in a serious bottleneck of the access network in between. As a result, ISP incurs disadvantages in their business. If this situation is known to ISP in advance, or if ISP is able to predict traffic volume end-to-end link high-load zone, ISP and end users would be able to decrease the gap for ISP service quality. In this paper, simulation tools, such as ACE, ADM, and Flow Analysis, were used to be able to perceive traffic volume prediction and end-to-end link high-load zone. In using these simulation tools, we were able to estimate sequential transaction in real-network for e-Commerce. We also imported virtual network environment estimated network data, and create background traffic. In a virtual network environment like this, we were able to find out simulation results for traffic volume prediction and end-to-end link high-load zone according to the increase in the number of users based on virtual network environment.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.49 no.4
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• pp.459-468
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• 2013

In the application of the ecosystem-based fisheries assessment Jeonnam marine ranching ecosystem, two fisheries, funnel fishery and trap fishery, were selected as target fisheries. Black seabream, Acanthopagru schlegelii, rock bream, Sebastes inermis, gray mullet, Mugil cephalus, were selected as target species for the funnel fishery, and conger eel, Conger myriaster, was target species for the trap fishery. For assessing indicators of four management objectives, that is the maintenance of sustainability, biodiversity, habitat quality and socio-economic benefits, indicators were selected considering the availability of data, which were 5 indicators for sustainability, 3 indicators for biodiversity, 4 indicators for habitat, 2 indicators for socio-economic benefit. The Objective risk indices for sustainability and biodiversity of two fisheries were estimated at yellow zone, medium risk level. The objective risk indices for habitat and socio-economic benefit were estimated at green zone, safe level. The species risk indices (SRI) were estimated at yellow zone. The fishery risk indices (FRIs) were estimated at 1.143 and 1.400 for funnel net fishery and trap fishery, respectively. Finally the ecosystem risk index estimated at 1.184.

• Journal of Coastal Disaster Prevention
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• v.4 no.spc
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• pp.245-253
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• 2017

In this study, surface currents measured by small lagrangian GPS drifters (Aquadrifter) in Anmok coastal waters were analysed to account for the variability of nearshore surface current and wave-induced current to understand sediment transport mechanism near the crescentic bars in the surf-zone and near Kangneung breakwater and submerged breakwater in Anmok. The 8 times lagrangian drifter experiments were conducted mostly during in 2nd, 3rd, 4th intensive measurements in winter, summer, and spring seasons with long-term wave observation at the station W1. The analysed surface currents near the breakwaters in Anmok show that wave-induced currents at the middle of the submerged breakwater were separated and flowed toward the shoreline but offshore currents were dominant through the channels between the breakwaters. The longshore currents near the shoreline were flowed to the northwest (southeast) depending on the incoming waves from ENE (NNE). The surface nearshore offshore currents were generated mostly by waves and winds in case of high and low wave energy environments. Using the small-size lagrangian surface drifter experiments, we successfully measured longshore and offshore wave-induced currents in the surf-zone and near submerged breakwater close to Kangneung breakwater. The drifter experiment results show the availability of direct observation of nearshore surface currents to understand the mechanism of sediment transport analysing observed wave-induced current and ebb-current in the surf-zone generated by incoming waves and local winds.

• Journal of the Society of Disaster Information
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• v.14 no.4
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• pp.440-449
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• 2018

Purpose: This study aims to design and verify an onsite EEWS that extracts the P-wave from a single seismic station and deduce the PGV. Method: The P-wave properties of Pd, Pv, and Pa were calculated by using 12 seismic waveform data extracted from historic seismic records in Korea, and the PGVs were computed using empirical equation on the P properties - PGV relationship and compared with the observed values. Results: Comparison of the observed and estimated PGVs within the alarm level shows the error rate of 86.7% as minimum. By reducing the PTW to 2 seconds, the alarm time can be shortened by 1 second and the seismic blind zone near the epicenter can be shortened by 6 Km. Conclusion: Through this study, we confirmed the availability of the on-site EEWS in Korea. For practical use, it is necessary to develop regression formula and algorithm reflect local effect in Korea by increasing the number of seismic waveform data through continuous observation, and to eliminate the noise from the site.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.55 no.9
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• pp.376-383
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• 2006

In this paper, autonomous information exchange methodology is studied between IEDs using SOAP protocol based on XML and PtP communication to archive the safety and reliability of large-scale system operation. The SOAP protocol has the advantages in the independency Problem for operating systems, using language, platforms and the security problem because it is XML-based RPC protocol. Inference-based solution of the IED is designed as rule-based solution so that the IED internal status, the system status or the faulted zone can be inferred autonomously using the internal data as well as information data obtained from free information exchange among other IEDS, Also, it is designed so that the inference results and the operation information are transmitted to the above SCADA system, and determined autonomously whether the commands from the SCADA are executed or not. Finally, The inference-based solution of IED and information exchange system among IEDS is implemented using MS Visual C++ MFC, MS SOAP and MS XML. Availability and accuracy of the proposed methodology and the design is verified from diversity simulation reviews for typical distribution substation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.366-369
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• 2014

Recently been viewed as a core technology of the IT industry, cloud computing services. It is expected that the market for cloud services industry showed a growth rate of 18.9% annually, to form a scale of $ 1,330 billion dollars in 2013, and to form a 1,768 billion dollars in 2015. Growth of cloud computing services industry, provides the operational efficiency and reduce costs for many companies, but the risks associated with it is also increasing. There is a problem that phenomenon is to lose control of the data on features of the cloud service, more data is gathered in one place, when a failure occurs, it is removed simultaneously the data of all devices. therefore, in the present paper is investigate the area a quick recovery with up to the problem and secure data storage INT the cloud computing service is available in only the data in the cloud service possible.