• Korean Journal of Remote Sensing
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• v.30 no.4
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• pp.445-454
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• 2014

In recent days, trend technologies for cloud, bigdata, or mobile, as the important marketable keywords or paradigm in Information Communication Technology (ICT), are widely used and interrelated each other in the various types of platforms and web-based services. Especially, the combination of cloud and mobile is recognized as one of a profitable business models, holding benefits of their own. Despite these challenging aspects, there are a few application cases of this model dealing with geo-based data sets or imageries. Among many considering points for geo-based cloud application on mobile, this study focused on a performance test of mobile cloud of Bayesian image fusion algorithm with satellite images. Two kinds of cloud platform of Amazon and OpenStack were built for performance test by CPU time stamp. In fact, the scheme for performance test of mobile cloud is not established yet, so experiment conditions applied in this study are to check time stamp. As the result, it is revealed that performance in two platforms is almost same level. It is implied that open source mobile cloud services based on OpenStack are enough to apply further applications dealing with geo-based data sets.

• Journal of KIISE:Information Networking
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• v.36 no.6
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• pp.545-551
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• 2009

In this paper, we propose the secure key management framework to connect USN with different network. Although connected USN with different network has no CA (Certificate Authority), it is important to use public key based cryptography system because this network consists of numerous devices. The proposed mechanisms focus on device authentication and public/private key management without existing PKI system of IP network. To solve no CA and certificate problems, the IDC (Identity Based Cryptography) concept is adopted in our proposed mechanism. To verify the possibility of realization, we make an effort to implement the proposed mechanisms to real system. In the test bed, both USN and PLC network are connected to IP network; and proposed mechanisms are implemented to PLC and sensor devices. Through this test using the proposed mechanism, we met the similar performance with symmetric algorithms on key generation and update process. Also, we confirmed possibility of connection between different network and device authentication.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.45 no.6
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• pp.52-59
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• 2008

Most pier performance analysis results for ad-hoc routing protocols have been based upon the model which each node in the network moves independently without restriction. In most real environments, however, it is very common for a group or multiple groups to move under the direction of group leader or group leaders instead of each node's independent movement. This paper presents the performance analysis of routing protocols for mobile ad-hoc network under group mobility environment. The comparative simulations have been made between a table-driven protocol, DSDV, and two on-demand protocols, AODV and DSR, under a group mobility model, RPGM, which is suitable for the practical applications such as military tactical operation. Multiple group movements are also included. The results show that the protocol performances for single group movement are very similar to node independent movement case. However some differences have been observed by varying pause time and connectivity.

• Journal of Internet Computing and Services
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• v.7 no.6
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• pp.157-174
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• 2006

Ajax interaction model changes the posture of web application to become a stateful over HTTP. Ajax applications are long-lived inthe browser. XMLHTTPRequest (XHR) is used to facilitate the data exchange. Using HTTPS over this interaction is not viable because of the frequency of data exchange. Moreover, switching of protocols form HTTP to HTTPS for sensitive information is prohibited because of server-of-origin policy. The longevity, constraint, and asynchronous features of Ajax application need to hove a different authentication and session fondling mechanism that invoke re-authentication. This paper presents an authentication and session management scheme using Ajax. The scheme is design lo invoke periodic and event based re-authentication in the background using digest authentication with auto-generated password similar to OTP (One Time Password). The authentication and session management are wrapped into a framework called AWASec (Ajax Web Application Security) for coupling to avoid broken authentication and session management.

• Geophysics and Geophysical Exploration
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• v.12 no.4
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• pp.355-360
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• 2009

This paper presents mobile robot based down-scale mineral resources exploration test system for the USN (Ubiquitous Sensor Network) based exploration. The system emulates the actual exploration environment. Underneath the metal free test plate, a metal object is attached. A magneto-meter mounted mobile robot runs around on the plate to find the metal. The measured magneto-meter values are transferred to the host PC via wireless network. The system enables to improve the reliability of simulation as well as to help efficient exploration system design. Metal-detecting experiments were carried out to illustrate the efficiency of the proposed system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.6A
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• pp.563-574
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• 2006

This paper implements SCM(Spatial Channel Model), a kind of ray-tracing method which has characteristics similar to realistic wave propagation environments, for link-level performance analysis of OFDM(Orthogonal Frequency Division Multiplexing) based multiple antenna systems. The SCM is proposed by 3GPP & 3GPP2 Spatial Channel AHG(Ad-hoc Group) for system-level performance validation. In this paper, we modify the system level parameters and channel coefficient of SCM to compare the link-level performances of OFDM based multiple antenna systems. Through computer simulations, we manifest the implemented SCM channel characteristics. We analyze a realistic link-level performance of OFDM based conventional MIMO(Multiple Input Multiple Output) system and smart antenna system in the implemented channel. We also include the link-level performance of OFDM based multiple antenna systems in I-METRA(Intelligent Multi Element Transmit and Receive Antenna) and independent channel environments with the same system parameters. We suggest appropriate multiple antenna system in the given environment by comparing the link-level performance in the spatial channels that have different channel correlation values.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.1
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• pp.193-197
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• 2015

Recently, the new issues for the safety and the information delivery system in the ship are raised. The deployment and the efficient algorithms of deploying the wireless sensor networks instead of using the built-in wired networks or the setup of the new wired networks is more desirable than the deployment of the wired networks in a ship after its final production since it can reduce the cost and the time of the brand new wired networks by reshaping some of the internal structure of the ship. In this paper, the shipboard signal propagation measurement system based on the signature sequence-three way slave mode are designed and its measureed data are analysed after measuring the signal propagation characteristics. Consequently, it is expected that the reliable and cost-effective signal measurement system with the three way algorithm for the deployment of the shipboard wireless networks can be achieved.

• Journal of Convergence for Information Technology
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• v.9 no.3
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• pp.16-21
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• 2019

Small and medium-sized Korean companies are currently changing their industrial structure faster than in the past due to various environmental factors (such as securing competitiveness and developing excellent products). In particular, the importance of collecting and utilizing data produced in smart factory environments is increasing as diverse devices related to artificial intelligence are put into manufacturing sites. This paper proposes an artificial intelligence-based smart factory model to improve the process of products produced at the manufacturing site with the recent smart factory. The proposed model aims to ensure the increasingly competitive manufacturing environment and minimize production costs. The proposed model is managed by considering not only information on products produced at the site of smart factory based on artificial intelligence, but also labour force consumed in the production of products, working hours and operating plant machinery. In addition, data produced in the proposed model can be linked with similar companies and share information, enabling strategic cooperation between enterprises in manufacturing site operations.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2023.11a
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• pp.23-26
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• 2023

In the past, in observing the sea fog on the major sea route and providing real-time information for the safe operation of ships, a visibility sensor or a fog detector with similar operating principles was installed to observe local fog near the place where it was installed. However, it was somewhat unreasonable to immediately provide sea fog observation information to ships and users because the reliability of real-time observation information was somewhat low due to pollution caused by dust, salt, and pollen, or malfunctions of detection sensors by organisms such as spider webs. From 2019 to 2022, the Korea Meteorological Administration and the Ministry of Oceans and Fisheries collaborated to build a more reliable real-time image-based sea fog observation system in 100 regions of the Lighthouse on major sea routes across the country to collect reliable sea fog observation information every 10 minutes and perform real-time public service(webpage).

• Journal of Engineering Education Research
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• v.6 no.2
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• pp.5-14
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• 2003

In this paper, we developed an efficient virtual experiment kit with creative and interactive multimedia contents, which can be used to enhance the quality of education in the area of digital logic circuits. Since our virtual experiment kit is implemented to describe the on-campus laboratory, the learners can obtain similar experimental data through it. Also, our web-based virtual experiment kit is designed to enhance the efficiency of both the learners and the educators. The learners will be able to achieve high learning standard and the educators save time and labor. The virtual experiment is performed according to the following procedure: (1) Circuit Composition on the Bread Board (2) Applying Input Voltage (3) Output Measurements (4) Checkout of Experiment Results. Furthermore, the circuit composition on the bread board and its corresponding online schematic diagram are displayed together on the virtual experiment kit for the learner's convenience. Finally, we have obtained several affirmative effects such as reducing the total experimental hours and the damage rate for experimental equipments and increasing learning efficiencies as well as faculty productivity.