• KIPS Transactions on Software and Data Engineering
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• v.4 no.12
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• pp.543-548
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• 2015

Recently top-k query processing has been extremely important along with the explosion of data produced by a variety of applications. Top-k queries return the best k results ordered by a user-provided monotone scoring function. As cloud computing service has been getting more popular than ever, a hot attention has been paid to cloud-based data outsourcing in which clients' data are stored and managed by the cloud. The cloud-based data outsourcing, though, exposes a critical secuity concern of sensitive data, resulting in the misuse of unauthorized users. Hence it is essential to encrypt sensitive data before outsourcing the data to the cloud. However, there has been little attention to efficient top-k processing on the encrypted cloud data. In this paper we propose a novel top-k processing algorithm that can efficiently process a large amount of encrypted data in the cloud. The main idea of the algorithm is to prune unpromising intermediate results at the early phase without decrypting the encrypted data by leveraging an order-preserving encrypted technique. Experiment results show that the proposed top-k processing algorithm significantly reduces the overhead of client systems from 10X to 10000X.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.21 no.3
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• pp.247-252
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• 2008

Recently, the virtual construction system in which project participants efficiently share and control the information throughout the life-cycle of construction project using 3D object models is being developed all over the world. In this paper, a design of interface between 3D object model of structures and structural analysis system that is essential for the analysis and design of civil structures in the virtual space is treated. The relation parametric modeling technique that is needed to make the 3D object models and the construction method of product breakdown structure(PBS) that considers the several parameters for the structural analysis are presented. PBS is built so that it is possible to extract needed attribute information from 3D object model and to apply it to the structural analysis. Design methodology for interface program is proposed that several numerical values determined by the cooperative work same as structural analysis are delivered to 3D object models without additional work. An interface program between 3D object models and structural analysis system developed based on the proposed method would be effectively used to develop virtual construction system.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.2D
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• pp.295-302
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• 2011

Ubiquitous is an information communication environment which peoples could connect on network without being conscious of the network and computer condition at anytime and anywhere. Presently, advanced technology, digital cities and eco-friendly cities using Ubiquitous technology are being focused through out the world. As recent information industry and communication technology have developed remarkably, studies on intelligent structures and structural maintenance methods by combining a general idea of connecting all objects on network by interpolating computers which is called Ubiquitous Computing, and USN(Ubiquitous Sensor Network) are being attempted. In this paper, a basic experiment on penetration of RF(Radio Frequency) sensor nodes using an experimental sample setting concrete and reinforcing bar as variables is studied to estimate the possibility of applying wireless sensor networks in structures. The spring of reinforcing bars, concrete thickness, intensity of radio frequency were set up as variables, transmitting and receiving distance were checked vertically and horizontally. Moreover, Spectrum Analyzer was used for checking the magnitude of the frequency used in order to measure the reduction of radio wave exactly. The radio wave reduction was numerically analyzed, and the influence of the wavelength was analysed as well. As a result, the penetration depth in concrete without reinforcing bars was 45cm, and in reinforced concretes which reinforcing bars placed at spacing of 5cm and 15cm, the penetration depth were 37cm and 45cm each. No influence on radio wave penetration depth were found when the spacing of reinforcing bars in the reinforced concrete structures becomes over 15cm.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.11
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• pp.1169-1174
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• 2015

Risk-Risk-based inspection (RBI) has been developed in order to identify risky equipments that can cause major accidents or damages in large-scale plants. This assessment evaluates the equipment's risk, categorizes their priorities based on risk level, and then determines the urgency of their maintenance or allocates maintenance resources. An earlier version of the risk-based assessment software is already installed within the equipment management system; however, the assessment is based on examination by an inspector, and the results can be influenced by his subjective judgment, rather than assessment being based on failure probability. Moreover, the system is housed within a server, which limits the inspector's work space and time, and such a system can be used only on site. In this paper, the development of independent risk-based assessment software is introduced; this software calculates the failure probability by an analytical method, and analyzes the field inspection results, as well as inspection effectiveness. It can also operate on site, since it can be installed on an independent platform, and has the ability to generate an I/O function for the field inspection results regarding the period for an optimum maintenance cycle. This program will provide useful information not only to the field users who are participating in maintenance, but also to the engineers who need to decide whether to extend the lifecycle of the power machinery or replace only specific components.

• Journal of the Korea Society of Computer and Information
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• v.16 no.11
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• pp.123-135
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• 2011

The domestic market of database in Korea is estimated to be over 3.663 trillion won. The data migration is getting to be more important along with the continuous growth of the database industry. g-CRM and private recommending function are examples of the service that can be given through coupling among customer database, product database, geographic information database, and others. The core infrastructure is also the database which is integrated, perfect, and reliable. There are not enough researches on efficient way of data migration and integrating process and investigation of migrated data though trends of database in IT environment as above. In connection with this issue, we have made a model for data migration on scientific and technological contents and suggest the result of data migration process adapting that model. In addition, we verified migration's exhaustiveness, migration's consistency, and migration's coherence for investigation of migrated data and database. From the result, we conclude data migration based on proper model has a significant influence on the database consistency and the data values correctness and is essential to maintain high qualified database.

• Journal of Digital Convergence
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• v.11 no.9
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• pp.229-238
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• 2013

Out-of-hospital cardiac arrest is a major public health problem in Korea. The survival rate to discharge remains at approximately 3.5% and only 1% have good neurological function. To increase the survival rate, prehospital care should restore spontaneous circulation. The purpose of this study was to analyze the factors associated with return of spontaneous circulation(ROSC) after out-of-hospital cardiac arrest. Data used for this study were collected from KCDC Out-of-Hospital Cardiac Arrest Surveillance 2009. As for the results of decision tree analysis, it is clear that prehospital CPR, cardiac arrest witness, activity, past history(cancer/heart disease/stroke), place, bystander CPR, response time, age, etc are significant contributing factors in ROSC. Among 16 cardiac arrest types from decision tree classification, the ROSC rate of type 1 is the highest(29.6%). Also notable is the fact that bystander CPR was strongly correlated with ROSC of patents with cardiac arrest occurring in non-public places. Community resources should be concentrated on increasing bystander CPR and early prehospital emergency care.

• Journal of Digital Convergence
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• v.17 no.12
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• pp.191-196
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• 2019

The development of open-pit mines leads to large-area topographical changes in highland forests and can lead to severe deterioration of forests, requiring continuous monitoring. The drone photogrammetry is performed at a lower altitude than the existing manned aerial photogrammetry, and thus has a relatively high accuracy. The purpose of this study is to construct spatial information of large open pit mine using drone photogrammetry and to evaluate the accuracy and utilization of the results. The accuracy of the drone photogrammetric results was 0.018 ~ 0.063m in the horizontal direction and 0.027m ~ 0.088m in the vertical direction. These results satisfy the permissible accuracy of 1: 1,000 digital topographic map and it can be used for open mine monitoring. The geospatial information of the open pit mine can be used in various ways, and it can be used to monitor the quantitative change of a specific area for time series change through data management by periodic data acquisition. If drone photogrammetry is applied to open-pit mine monitoring in the future, work time and cost can be greatly reduced compared to the conventional GNSS or total station method, and the work efficiency can be greatly improved because more visible data can be generated.

• Korean Journal of Environment and Ecology
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• v.25 no.4
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• pp.581-589
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• 2011

The purpose of this study is to investigate the structure of vegetation dominated by deciduous broad-leaved trees at the Beomeosa(Temple) Valley of Mt. Kumjungsan in Busan. To this end, 28 plots were set up and surveyed. The result analyzed by TWINSPAN, one of the classification technique, showed that the communities were divided into six groups which are Carpinus tschonoskii-Deciduous broad-leaved forest community(I), Quercus serrata-C. tschonoskii community(II), C. tschonoskii-Q.s serrata-Pinus densiflora community(III), C. tschonoskii-Quercus serrata-Q. mongolica communtiy(IV), Q. serrata-Deciduous broadleaved forest community(V) and Chamaecyparis obtusa-C. tschonoskii community (VI). Species diversity ranged from 0.3832 to 0.0450. The lowest diversity was Chamaecyparis obtusa community(VI) but the highest was Carpinus tschonoskii-Deciduous broad-leaved forest community(I) and Q. serrata-Deciduous broadleaved forest community(V). The average number of species was 6.8${\pm}$3.2 in the unit area(100$m^2$). Carpinus tschonoskii community at the Beomeosa Valley of Mt. Geumjeongsan was a climatic climax forest having a value to preserve, so a continuous management will be needed.

• Culinary science and hospitality research
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• v.21 no.1
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• pp.191-209
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• 2015

The purpose of this study is to identify whether franchisee-perceived franchisor's proactiveness, innovativeness and risk-taking affect franchisee-perceived affective commitment with franchisor, and the affective commitment affects franchisee-perceived external representation and service delivery. Based on total 280 samples obtained from owners or managers of franchise fast-food restaurants in located in Yeongnam province, the research findings are as follows. Firstly, the innovativeness and risk-taking positively affect the affective commitment. Secondly, the affective commitment positively affects external representation and service delivery. But proactiveness does not affect the affective commitment significantly. These findings imply that firstly, franchisor should investigate consumer trends periodically and develop new successful menus and services more than competitors do, and implement new marketing techniques innovatively towards these menus and services. Secondly, franchisor had better adopt high return/risk strategies because of deepened competition and do bold decisions of price change etc. Also, in order to increase proactiveness, franchisor needs to launch new menus and services earlier than competitors and occupy market in advance, which strengthens affective commitment with franchisees. Thirdly, in order to increase affective commitment with franchisees, franchisor needs to match franchisor's value with franchisee's value and same value means same objective. Lastly, limitations and further research directions are also discussed.

• The Journal of Society for e-Business Studies
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• v.18 no.1
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• pp.107-127
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• 2013

The evolution of IT facilitated the communication and knowledge sharing between the social network service (SNS) users. When the more information about SNS users had been posted in SNS site, SNS users had sometimes exposed in the risk of privacy invasion. To remedy this problem, we had introduced the information control mechanisms from the prior studies in data management to the SNS area and empirically validated the effect of these mechanisms in this research. Three information control mechanisms had been elected as access control, reference control and diffusion control. We had conducted a survey to the Facebook users which is the most famous SNS site. 459 data had been gathered and analyzed by PLS algorism. As the results, reference control and diffusion control has significantly increased the trust on SNS providers and decrease the privacy concern. This change could significantly affect on the satisfaction with the SNS site and knowledge sharing intention of SNS users. This study could introduce the new perspective about privacy protection issues in SNS area. Also, the information control mechanisms suggested in this study could contribute to make more robust privacy protection mechanisms in SNS site in practice.