• ETRI Journal
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• v.37 no.2
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• pp.369-379
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• 2015

Fault management of virtualized network environments using user-driven network provisioning systems (NPSs) is crucial for guaranteeing seamless virtual network services irrespective of physical infrastructure impairment. The network service interface (NSI) of the Open Grid Forum reflects the need for a common standard management API for the reservation and provisioning of user-driven virtual circuits (VCs) across global networks. NSI-based NPSs (that is, network service agents) can be used to compose user-driven VCs for mission-critical applications in a dynamic multi-domain. In this article, we first attempt to outline the design issues and challenges faced when attempting to provide mission-critical applications using dynamic VCs with a protection that is both user-driven and trustworthy in a dynamic multi-domain environment, to motivate work in this area of research. We also survey representative works that address inter-domain VC protection and qualitatively evaluate them and current NSI against the issues and challenges.

• Journal of Digital Contents Society
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• v.19 no.5
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• pp.1003-1010
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• 2018

When an applicant requests the emergency situation call or safe return service using a smart device, the smart surveillance service can select the CCTV(closed circuit television) cameras around the applicant using applicant's location information, then automatically takes a photograph to track the applicant. Since the surrounding CCTV camera shoots the applicant continuously using location information and the applicant can be observed by the monitor agent in real time, this service can be very helpful in an applicant's emergency situation or safe return. The existing smart surveillance service does not consider the priority of the emergency situation call and safe return service. Therefore, there is the disadvantage that the applicant who requests an emergency situation call service can not be photographed when safe return service has already preoccupied CCTV cameras which are capable of taking a picture of the applicant. The proposed smart surveillance service improves this disadvantage by using service priority.

• The Transactions of the Korea Information Processing Society
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• v.7 no.5
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• pp.1536-1543
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• 2000

In this paper, we propose a multiple access scheme for efficient transmission of realtime and non-realtime data in IMT-2000 through cdma2000's CDMA MACD. On the contrast to the conventional circuit-based service, this framework is packet-oriented service. maximum number of simultaneous subscribers increases due to the statistical multiplexing based on variable transmission rate of realtime data. System performance is evaluated and compared with conventional circuit-based scheme considering transmission delay and channel utilization by computer simulation.

• Journal of Internet Computing and Services
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• v.7 no.2
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• pp.93-102
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• 2006

Traditionally, diffusion of telecommunications services has been considerably affected by presence of critical mass and network externalities, and thus shown the so-called late take-off phenomenon. However, as telecommunications network evolves from circuit switching to packet switching, enabling diverse new services such as Internet access, Internet banking and web hosting, it seems this traditional diffusion patterns are changing. By comparing diffusion of the packet-based services with those of circuit-based services and durable goods, we have found the late take-off phenomenon is not involved in diffusion of newly introduced the packet-based services. Moreover, we concluded diffusion of the packet-based services is much faster than that of durable goods, thus showing early take-off phenomenon. Based on this empirical result, we suggest Telcos and ISPs should pay as much attention to the growth state as the introduction stage in order for their packet-based services to be successful in the markets.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.10
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• pp.2373-2379
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• 2015

COMS(Communication, Ocean and Meteorological Satellite), the first Korean geostationary meteorological satellite, provides free meteorological information through HRIT/LRIT(High/Low Rate Information Transmission) service. This work presents the development of data receiver circuit that is essential to the implementation of a low-cost meteorological information receiver system. The data receiver circuit processes the data units according to the specification of physical layer and data link layer of HRIT/LRIT service. For this purpose, the circuit consists of a Viterbi decoder, a sync. word detector, a derandomizer, a Reed-Solomon decoder and so on. The circuit also supports PCI express interface to pass the information data on to the host PC. The circuit was implemented on an FPGA(field programmable gate array) and its function was verified through simulations and hardware implementation.

• The KIPS Transactions:PartC
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• v.10C no.2
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• pp.209-216
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• 2003

As the interest in the wireless internet services is increasing recently, the related technology development is in active progress. According to WAP (Wireless Application Protocol) specification which is currently considered as one of the most powerful international standardizations, mobile terminal and WAP server are supposed to communicate through WAP Gateway. This paper is about the design and implementation of IWAP platform where WAP Gateway and Server are integrated and supported based on Linux. The proposed WAP platform broadly consists of four modules like WAP Gateway, JAVA based Server development environment, WML Tool-Kit, and MUL (Management User Interface) and for bearer network, SMSC (Short Message Service Center) and CSD (Circuit Switched Data) router are considered.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.9
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• pp.787-796
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• 2013

In this paper, the visible light communication (VLC) techniques based on the carrier modulation are considered in order to realize the VLC application service that has the functions of the high speed optical sensing and the wide range reception from VLC transmitter. The VLC hardware circuits based on the 32.768 kHz low frequency carrier and 4 MHz high frequency carrier are designed and implemented respectively, and the signal waveform generated from the implemented circuits are observed. In addition, various performance experiments are done with the prototypes.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.11
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• pp.902-910
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• 2013

The most representative research network in Korea, KREONET, has developed DynamicKL, an advance reservation based Network Service Agent (NSA) for user driven virtual circuit services. DynamicKL provides reservation, provisioning, release, termination, and inquiry web services for network resources by using an open standard network service interface (NSI), as well as web services for network resources by using a GUI interface. In addition, it has the RICE interface to support a protection management function per VC for virtual circuits and reservations. In this article, a protection management per VC for provisioned VCs and reservations is addressed in the DynamicKL framework, as a contribution to the VC protection management issue, which results in more manageable and reliable VC services compared to other advance reservation frameworks. An administrator can detect successful or unsuccessful VC protections in the event of a primary link failure and successful or unsuccessful VC retrievals after a primary link repair, by using RICE.

• Journal of Communications and Networks
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• v.9 no.3
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• pp.319-329
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• 2007

This paper presents a price-based quality-of-service (QoS) control framework for two-class network services, in which circuit-switched and packet-switched services are defined as "premium service class" and "best-effort service class," respectively. Given the service model, a customer may decide to use the other class as a perfect or an imperfect substitute when he or she perceives the higher utility of the class. Given the framework, fixed-point problems are solved numerically to investigate how static pricing can be used to control the demand and the QoS of each class. The rationale behind this is as follows: For a network service provider to determine the optimal prices that maximize its total revenue, the interactions between the QoS-dependent demand and the demand-dependent QoS should be thoroughly analyzed. To test the robustness of the proposed model, simulations were performed with gradually increasing customer demands or network workloads. The simulation results show that even with substantial demands or workloads, self-adjustment mechanism of the model works and it is feasible to obtain fixed points in equilibrium. This paper also presents a numerical example of guaranteeing the QoS statistically in the short term-that is, through the implementation of pricing strategies.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.237-240
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• 2005

We propose a fully converged Ethernet and TDM transport system. Developed Ethernet and TDM convergence system can support not only L2VPN service and premium multimedia service based on MPLS protocol but also TDM leased line service, simultaneously. Developed convergence system can provide high reliability for Ethernet data due to support protection and restoration function of circuit based networks. Evaluation for Ethernet and TDM path was successfully performed to show the typical application of the proposed system in the legacy networks.