• ETRI Journal
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• v.32 no.2
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• pp.241-247
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• 2010

We propose and experimentally demonstrate a service-aware optical transport system. The proposed service-aware optical transport system makes a flow based on service type and priority of traffic. The generated flow is mapped to a corresponding sub-${\lambda}$ for transport over an optical network. Using sub-${\lambda}$ provided by the centralized control plane, we could effectively provide quality-of-service guaranteed Ethernet service and best-effort service simultaneously in a single link. The committed information rate (CIR) traffic and best-effort traffic are assigned to different sub-${\lambda}s$. The bandwidth of the CIR traffic is guaranteed without being affected by violation traffic because the bandwidth is managed per each sub-${\lambda}$. The failure detection time and restoration time from a link failure is measured to be about 60 ${\mu}s$ and 22 ms, respectively, in the ring network. The measured restoration time is much smaller than the 50 ms industry requirement for real-time services. The fast restoration time allows the proposed service-aware optical transport system to offer high availability and reliability which is a requirement for transport networks.

• Proceedings of the Korea Contents Association Conference
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• 2004.11a
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• pp.78-83
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• 2004

In the early days, we could be provided almost internet contents without pay. It's been turning out the time we need to pay for getting some internet contents as it has become one of important media. It's already been a kind of big market. We need to develop the revenue model of character brand in the internet business. Character brand could make the internet contents on a position of advantage. We've made the revenue through using character brand and making commodities and services more valuable. We use the internet in a wide range of daily life communication. It's expected to extend. It's needed to study which kind of revenue model is existed at the moment.

• Korean Journal of Remote Sensing
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• v.21 no.5
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• pp.433-443
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• 2005

This paper show that, without installation of expensive VR (Virtual Reality) program, the sharing information is possible through posting three-dimensional road structures on the web, and avoiding the conventional top-down decision making method, fast bottom-up communication is possible base on the Virtual GIS (Geographic Information System). In this paper, using Viewpoint Scene Builder, internet-based software, the transformation was conducted to give pertinent type for web posting. In order to use the completed route at the scene builder, the output with ASCII Export is required, and ASE (ASCII Scene Export) contains the property information including the coordinate and frame of mesh vertex. Through in advance recognition of the problems regarding route design and petition due to environmental rights infringement, the time and cost due to design alteration can be reduced. It's difficult to provide VR based on the internet because file that embodied with internet GIS was complicated and its capacity comes to scores of mega-bites. But, this study provides VR with internet according to a basis by simplification of files.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.1C
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• pp.1-10
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• 2002

With the explosive growth of the number of Internet users and Internet-related services, the research on construction of broadband Optical Internet by using WDM technologies is actively is actively progressed. In this paper, we design the offset time decision (OTD) algorithm for supporting the QoS in optical networks based on optical burst switching (OBS), which is the new switching paradigm, and evaluate the performance of it. The proposed algorithm determines a reasonable offset time considering traffic load of network and the number of wavelengths to guarantee the burst loss rate (BLR) of high priority Internet traffic as a QoS parameter. In order to design the proposed OTD algorithm, firstly we make the new burst loss formula, which includes the effect of offset time. The decision of offset time corresponding to the requested BLR, however, should use the reverse formula of proposed one, thus we are not able to use it without any changes. In this paper, we define the heuristic loss formula (HLF) that can be changed into reversed formula by using the proposed formula and proportional equation considering its characteristics. Finally we show the OTD algorithm to decide the offset time by using HLF. We show that the requested BLR is guaranteed under various traffic load with the determinded offset time by using the proposed OTD algorithm.

• School Mathematics
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• v.5 no.4
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• pp.459-476
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• 2003

Internet was introduced to this study for making mathematics class the surroundings where students can solve the mathematics problems and communicate mathematically in a free way without restriction of time and place. With the intention of investigating mathematical communication and problem solving in mathematics education using internet, the objects of this study were determined as follows: First, how does a student express mathematical idea in problem solving using internet\ulcorner Second, is there any difference in the degree of participation of mathematical communication according to schoolwork accomplishment and characteristics of the student\ulcorner Third, what's the effect of class using internet on problem solving of mathematics class\ulcorner A case study was executed for the solution and the subjects were all students(44 persons) of a class in the fourth grade of elementary school in D city got into web-site of internet and had class with it and 8 students out of them were deeply analyzed. Their results were shown on internet, and eight of them had interview for deep research after survey with questionnaires for all of the students after class. The results and the conclusions of this study were as follows: First, it showed that there was various types(simple statement, fact enumerating, logical thinking, using letters and formula, insufficiency of explanation) of the mathematical idea expression in internet according to students and study using internet seems to be helpful to the improvement of logical his own expression through other students' expression. Second, it showed that there was difference in mathematical communication participation according to the student's characteristics and it helped students of poor schoolwork be interested and confident in mathematics. Third, it showed that pattern study using internet had effect on forming a habit of reason and verification in problem solving in mathematics class. Accordingly, pattern study using internet seems to have a positive effect on increasing mathematical interests and solving problems in mathematics class.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.6
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• pp.119-123
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• 2010

The transmission performance of 10Gb/s optical duobinary transmitters implemented by using a Mach-Zehnder(MZ) modulator and an optical delay interferometer is presented. We investigated the theoretical impact of transmission systems by the modulator driving voltage ratio(=driving voltage/switching voltage) and the optical interferometer time delay to improve transmission distance using computer simulation. By reducing the driving voltage ratio and optimizing the partial bit time delay, the transmission performance has been improved greatly.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.7
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• pp.3050-3065
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• 2016

Neural networks (NNs) are extensively used in applications requiring signal classification and regression analysis. In this paper, a NN based threshold selection algorithm for 60 GHz millimeter wave (MMW) time of arrival (TOA) estimation using an energy detector (ED) is proposed which is based on the skewness, kurtosis, and curl of the received energy block values. The best normalized threshold for a given signal-to-noise ratio (SNR) is determined, and the influence of the integration period and channel on the performance is investigated. Results are presented which show that the proposed NN based algorithm provides superior precision and better robustness than other ED based algorithms over a wide range of SNR values. Further, it is independent of the integration period and channel model.

• International Journal of Internet, Broadcasting and Communication
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• v.12 no.3
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• pp.1-8
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• 2020

This paper studied a method of estimating target information using a radar in wireless communication. Position information on the target can be estimated angle, distance and velocity. The velocity information can be estimated since the Doppler frequency is changed in the moving target. The signal incident on the receiving array antenna is multiplied by the delay time and the reference signal to represent the output signal. This output signal is estimated by applying FFT (Fast Fourier Transform) after calculating signal correlation through correlation integrator. Since the output signal must be calculated within the correlator, it should be processed with the Dwell time. The correlation signal of the correlation integrator outside this Dwell time is indicated by the velocity measurement error. The FFT is applied to the signal that has passed through the correlated integrator in order to estimate the distance of the signal. The Doppler resolution must be improved because the FFT estimates target information using the Doppler information. The Doppler resolution decreases with increasing the integration time. The velocity information estimation should have no spread of the velocity. As a result of the simulation, there was no spread of the target velocity in this study.

• Journal of the Korean Institute of Intelligent Systems
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• v.13 no.1
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• pp.76-84
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• 2003

Now days, It is based on GIS and GPS, it can search for the shortest path and estimation of arrival time by using the internet and cell phone to driver. But, even though good car navigation system does not create which is the shortest path when there average vehicle speed is 10 -20 Km. Therefore In order to reduce vehicle waiting time and average vehicle speed, we suggest optimal green time algorithm using fuzzy adaptive control, where there are different traffic intersection length and lane. In this paper, it will be able to forecast the optimal traffic information, estimation of destination arrival time, under construction road, and dangerous road using internet.

• Journal of Communications and Networks
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• v.11 no.4
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• pp.416-427
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• 2009

Domain name system (DNS) is a primary identification mechanism for Internet applications. However, DNS resolutions often take an unbearably long time, and this could seriously impair the consistency of the service quality of Internet applications based on DNS such as World Wide Web. Several approaches reduce DNS resolution time by proactively refreshing expired cached records or prefetching available records beforehand, but these approaches have an inherent problem in that they cause additional DNS traffic. In this paper, we propose a DNS resolution time reduction scheme, named renewal using piggyback (RUP), which refreshes expired cached records by piggybacking them onto solicited DNS queries instead of by issuing additional DNS queries. This method decreases both DNS resolution time and DNS traffic since it reduces the number of queries generated to handle a given DNS resolution without generating additional DNS messages. Simulation results based on two large independent DNS traces show that our proposed approach much reduces not only the DNS resolution time but also the DNS traffic.