• The KIPS Transactions:PartC
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• v.12C no.1 s.97
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• pp.105-110
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• 2005

With the proliferation of multimedia group applications, the construction of multicast trees satisfying QoS requirements is becoming a problem of prime importance. In this paper, we study the delay- and delay variation-bounded multicast tree (DVBMT) problem which is NP-complete. The problem is to construct a spanning tree for destination node, which has the minimized multicast delay variation, and the delay on the path from the source to each destination is bounded. A solution to this problem is required to provide decent real-time communication services such as on-line games, shopping, and teleconferencing. Performance comparison shows that the proposed scheme outperforms DDVCA which is known to be effective so far in any network topology. The enhancement is up to about $3.6{\%}{\~}11.1{\%}$ in terms of normalized surcharge for DUVCA. The time complexity of our algorithm is $O(mn^2)$.

• The Transactions of the Korea Information Processing Society
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• v.5 no.1
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• pp.63-72
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• 1998

Diversity in hardware and software is increasing ever and our networked computing environment is becoming more diverse. The development of software becomes expensive works because of a collection of diverse computers, storing various data type in different places, working together by incompatabilities of operating system and various databases and protocols. CORBA is a standard for distributed computing environment and for system integration of heterogeneous distributed environment. CORBA provides many technical benefits for effective system integration and seamless infrastructure for distributed communication environment of heterogeneous systems. In this paper, we proposed a system integraton model based on CORBA for distributed object environment, softwarc reuse and the intcrconnecion of WWW. The model is composed of factory server, trading server, convcrsion scrvcr and applicaton scrvcr. Thc proposed model can easy application development and system integration. And we implcmcntcd thc gateway for cooperation with WWW. As a proof of the proposed model, we show how the distance learning system designed using the services provided by the proposed model.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.520-523
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• 2010

In the field of network sense for the Ubiquitous environment, the technology of RFID is a significant part. Due to the real time processing of information and the property of network, RFID has been used in service field such as distribution, administrative control of physical distribution, remote measuring device, and security, instead of currently used bar-code. The management system of port facilities using the current RFID technology has the effects of reducing working hours and improvement in data processing, but it is not proper for human resource allocation since it is dominantly worked for physical resources. In this paper, we designed and implemented personnel control system using RFID of 2.4GHz in port facilities which presents a monitoring system for safety operation and increase of efficiency using RFID in order to overcome the limitations and problems of current port operation management techniques.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.6
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• pp.101-109
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• 2009

The people around industrial complexes and polluted areas suffer from the many occurrences of odors, and frequently issue a request for solving the odors to their local government in charge of those areas. Recently local governments whose regions have a number of such areas have a great interest in monitoring odor occurrences and gathering air on demand. This paper proposes a system in which a user can perform real-time monitoring the values of odor and atmospheric sensors, and the management of odor sensing devices using the Internet browser. Compared to previous systems, the system has an advantage of providing the functions for controlling and managing a number of devices irregardless of the location of the user. Also, the system is built around a blackboard-based multi-process architecture, enabling the easy incorporation of a new software model to be found useful. To our experiment, users showed great satisfactions in terms of the easiness of use. Our system has been installed and operated in an area of a local government in which odors are likely to occur.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.1
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• pp.151-156
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• 2017

In case of massive water leakage, it's crucial for field manager to quickly positioning the problematic valve and related ones. However, it's not easy for the system to find the corresponding valve and even if it's found, it can not respond quickly because it can't know the relevant information immediately. In this paper, we implement the system for identifying sluice valve positions using GPS and AR techniques. The proposed system is composed of hand held android device, remote database server and data acquisition device for DB creation. We utilize the android device's sensors including GPS, gyro, accelerometer, magnetic sensor. The system identifies the valve with matching between the position data from the remote database server, and current GPS locations of device. We use AR techniques to overlay the graphics pattern of valve positions and some additional informations on captured real scene. With this system, it will be fast and accurate for maintenance of sluice valve of municipal water system.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.2
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• pp.227-234
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• 2012

Development of Computer science and internet technoloy have led changes all over the social area. Educational markets based on this circumstance are offering various services named remote education, cyber lecture, e-Learning, etc. Due to these products, systems for computer based teaching and evaluating student's achievement are wide spread. But in many systems we can find functional restrictions. In this paper we propose a RTE system offering interactive self control mode based education so as to provide customized education for each individual by realtime feedback of the level of the student's comprehension we expect that this system provides customized education environment considering student's achievement level and maximizes their motivation.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.9
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• pp.953-958
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• 2015

Raspberry Pi is a credit card-sized computer with support for a large number of input and output peripherals. This makes it the perfect platform for interaction with many different devices and for usage in a wide range of applications. When combined with Wi-Fi, it can communicate remotely, therefore increasing its suitability for the construction of wireless sensor nodes. In addition, data processing and decision-making can be based on artificial intelligence, what is performed in developed testbed on the example of monitoring and determining the confidence of fire. In this paper, we demonstrated the usage of Raspberry Pi as a sensor web node for fire-safety monitoring in a building. When the UV-flame sensors detect a flame as thin as that of a candle, the Raspberry Pi sends a push-message to notify the assigned smartphone of the on-site situation through the GCM server. A mobile app was developed to provide a real-time video streaming service in order to determine a false alarm. If an emergency occurs, one can immediately call for help.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.6
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• pp.827-832
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• 2002

The development of dedicated network management system is essential to meet the following conditions: the system must run the configuring and repair processing for the dedicated communication network, and can manage new next generation data dedicated communication network of various types. In general it is effective that the system is consisted of decentralized module to be accessible for business logic and datum to remote area. To solve these problems, a method is to use object-oriented design techniques. That is, it is to abstract reusability objects and make component module using the abstracted objects. In this paper, we propose a management system of dedicated communication network service using object-oriented design techniques which are UML(Unified Modeling Language).

• Journal of the Korean Institute of Intelligent Systems
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• v.26 no.1
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• pp.82-86
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• 2016

This paper proposes a method for the immobilization of motorbike brakes in conjunction with near-field communication (NFC) technology in order to meet the increasing demand for security and convenience of motorbike drivers. We thought about the concept of wireless key, NFC security devices and automatic solenoid valve for setting the lock and unlock module. This paper propose the design and development of an innovative anti-theft alarm system for motorcycles using NFC smart devices based on RFID system, the basis of IoT and AES(advanced encryption standard) encryption Algorithm. The design concept is based on NFC communication strategy between the vehicle and owner. To do this concept, we designed motorcycle smart key system with general-purpose NFC system and the automatic solenoid valve for setting the lock and unlock module. First, we designed control unit and NFC card reader for motorcycle smart key system. Then we propose an AES encryption algorithm and prove that the motorcycle key system is controllable by showing the result of implementing and testing, after installing.

• Journal of Satellite, Information and Communications
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• v.8 no.1
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• pp.14-22
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• 2013

GPS radio occultation is a remote sensing technique probing atmospheric properties based on the fact that GPS signal is refracted and delayed by atmosphere. The FORMOSAT-3/COSMIC mission jointly developed by the USA and Taiwan is providing about 2500 occultation soundings a day on the near real-time basis. The Korean KOMPSAT-5/AOPOD system is preparing to launch for monitoring troposphere and ionosphere using a dual frequency GPS receiver and the antenna for occultation data acquisition. In this paper, we examine the methods for signal processing and the geometry analysis for GPS radio occultation, and look into the retrieval techniques for the temperature and humidity of troposphere and the electron density and scintillation of ionosphere. Using these atmospheric properties, we aim to derive the strategies for applying GPS radio occultation to space weather, for example, ionospheric TEC(total electron content) analysis for earthquake monitoring and the Open API(application programming interface) development for more effective data service.