• Journal of KIISE:Databases
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• v.29 no.4
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• pp.285-296
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• 2002

When a client requests a set of data items at once, it is crucial to reduce the total time elapsed till the client receives all data items requested. This paper describes a data broadcasting technique that reduces access time for multiple data accesses from clients. The impact of the relative position of each data item in a broadcast schedule is dependent on the degree of data replication between data requests from clients. The relative broadcast frequencies for data items are affected by the degree of access skewness from clients. This paper proposes a technique for generation of a hierarchical data broadcast schedule, which can support multiple data accesses effectively by considering the data sharing among client requests and data access skewness together. Simulation results show that the proposed technique consistently performs better than the previous research results in various environments.

• The KIPS Transactions:PartC
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• v.18C no.4
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• pp.227-236
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• 2011

IPTV(Internet Protocol Television) is one of the typical businesses which are the convergence of Broadcast and Communication. It provides broadcasting service using IP networks. Recently, IPTV service is developed to Mobile IPTV or Open IPTV. Especially, Open IPTV uses open platform so not only service providers but also general users can provide contents to other users. Open IPTV system has many content providers, so existing security solution of IPTV cannot be adopted. In this paper, we suggest user authentication and key distribution mechanism on Open IPTV. Our proposed mechanism is based on Kerberos, so it can support distribution environment such as Open IPTV. We demonstrate that proposed mechanism can guarantee secure transmission of contents and reduce the delay of user authentication on Open IPTV system compared to other authentication mechanisms. We also compare our proposal and other mechanisms in various aspects, and analyze efficiency and safety of proposed mechanism. As a result, we insist that this mechanism satisfies the security requirements for IPTV.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.803-806
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• 2016

'Pokemon Go',which is game program, provides a clue to solve the problem of healthcare in the sense of leading changes in behavior of the users. 'Pokemon Go'is a spin-off of the $Pok{\acute{e}}mon$ game series and uses Augmented Reality(AR) technology. AR, which can be said to complement the real world, has been used in many fields such as medical applications, broadcasting, manufacturing, the mobile sector as a wide range of technologies. In particular, the medical field as area of the active application from the start of AR, provides a great help in medical fields, that is accurate medical diagnosis and prevention of unnecessary dissection by synthesizing the patient information and the image of actual patient on three-dimensional data of the sensor such as MRI or ultrasonic wave. In this study, we analyze the VR technology trends, application examples, and the future of VR and AR based medical services in healthcare.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.5 s.108
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• pp.461-475
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• 2006

In this paper, it is described about the tri-band mobile antenna system design to provide broadband multimedia and direct broadcasting services using goo-stationary Koreasat 3, simultaneously operated in Ka/K/Ku band. The radiating part of the antenna system with a fan beam characteristic in the elevation plane is composed of the quasi-offset dual shaped reflector and the tri-band feeder. The tri-band feeder is also composed of the Ka/K dual band feeder with the protruding dielectric rod, the circular polarizer, the ortho-mode transducer and the circular-polarized Ku band feed array. Especially, the Ka/K dual band circular polarizer was realized firstly using the comb-type structure. For fast satellite-tracking on the movement, the Ku band feed array has the structure of the $2{\times}2$ active phased array which can make electrical beams. And, the circular-polarized characteristic in the feed array was improved by $90^{\circ}$ rotating arrangement of four radiating elements polarized circularly by a $90^{\circ}$ hybrid coupler, respectively. Four beam forming channels to make electrical beams at Ku band are divided into the main beam channel and the tracking beam channel in the output, and noise temperature characteristics of each channel were analyzed on the basis of the contributions of internal sub_units. From the fabricated antenna system, the output power at $P_{1dBc}$ of Ka_Tx channel was measured more than 34.1 dBm and the measured noise figures of K/Ku_Rx channels were less than 2.4 dB and 1.5 dB, respectively, over the operating band. The radiation patterns with co- and cross-polarization in the tri-band were measured using a near-field measurement in the anechoic chamber. Especially, Ku radiation patterns were measured after correcting each initial phase of active channels with partial radiation patterns obtained from the independent excitation of each channel. The antenna gains measured in Ka/K/Ku band of the antenna system were more than 39.6 dBi, 37.5 dBi, 29.6 dBi, respectively. And, the antenna system showed good system performances such as Ka_Tx EIRP more than 43.7 dBW and K/Ku_Rx G/T more than 13.2 dB/K and 7.12 dB/K, respectively.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.3
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• pp.35-43
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• 2023

The purpose of this study is to research digital twin policies for the use of administrative services. The study was conducted through a mobile survey of 1,000 participants, and the results are as follows. First, in order to utilize digital twin technology, it is necessary to first identify appropriate services that can be applied from the perspective of Gyeonggi Province. Efforts to identify digital twin services that are suitable for Gyeonggi Province's field work should be prioritized, and this should lead to increased efficiency in the work. Second, Gyeonggi Province's digital twin administrative services should prevent duplication with central government projects and establish a model that can be connected and utilized. It should be driven around current issues in Gyeonggi Province and the demands of citizens for administrative services. Third, to develop Gyeonggi Province's digital twin administrative services, a standard model development plan through participation in pilot projects should be considered. Gyeonggi Province should lead the project as the main agency and promote it through a collaborative project agreement. It is suggested that a support system for the overall project be established through the Gyeonggi Province Digital Twin Advisory Committee. Fourth, relevant regulations and systems for the construction, operation, and management of dedicated departments and administrative services should be established. To achieve the realization of digital twins in Gyeonggi Province, a dedicated organization that can perform various roles in project promotion and operation, as well as legal and institutional improvements, is necessary. To designate a dedicated organization, it is necessary to consider expanding and reorganizing existing departments and evaluating the operation of newly established departments. The limitation of this study is that it only surveyed participants from Gyeonggi Province, and it is recommended that future research be conducted nationwide. The expected effect of this study is that it can serve as a foundational resource for applying digital twin services to public work.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.3 no.4
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• pp.59-88
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• 2008

For the success of the DMB market to meet consumers' demands for Ubiquitous Media and strengthen the nation's competitiveness, it's inevitable for us to activate DMB advertising as of main profit source for DMB Media, and to develop various types of DMB advertising which are linked to the profit model. So I'd like to look over the various types of DMB advertising which are suitable for DMB features as one of the efforts to activate DMB advertising. First of all, I've figured out what kinds of advertising are available for new media and which related technologies are required for DMB media. Through this research, I could find out what features of new media such as cable broadcasting, Internet and Mobile have become the source of developing various types of advertising and how to a great part to activate new media advertising markets by making the best use of their media features. This research also shows that DMB advertising has the high potential to be developed in various and effective types and kinds of advertising with its media feature and technological feature. This research observing DMB advertising cases showed that DMB advertising can be divided into 6 types such as forms, purposes, techniques, advertising positions, the use of LBS(Location Based Service), coupons and it could be developed into various kinds of DMB advertising dependent on each type. On the other hands, it would be great to have continual researches and follow-ups for various types of DMB advertising and the verification of the effectiveness for DMB advertising by performing potential DMB advertising.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.7
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• pp.86-91
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• 2016

To solve the problem of the excessive error caused by using a single value for the shielding effect of the neutral line of an electric power distribution line in the calculation of the voltage it induces in a telecommunication line, the general expression that was previously developed to reflect the mechanism of voltage induction by a distribution line with multiple grounds is employed in this paper to represent the relationship between the leakage current rates at each ground pole. In this way, the formula for calculating the shielding effect of the neutral line can be factorized against the unbalanced current flowing in the neutral line, which is the root current of induction. This shielding coefficient of the neutral line is not constant, but can vary when a range of induced voltages is generated in the whole power distribution line. The calculation method developed herein reduces the error rate to one tenth of that of the existing calculation result in the case of overestimation and increases it by 14% in the case of underestimation.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.9
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• pp.835-842
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• 2009

DVB-SSP is a new broadcasting system for hybrid satellite communications, which supports mobile handheld systems and fixed terrestrial systems. However, a critical factor must be considered in upper layer decoding which including erasure Reed-Solomon error correction combined with cyclic redundancy check. If there is only one bit error in an IP packet, the entire IP packet is considered as unreliable bytes, even if it contains correct bytes. IF, for example, there is one real byte error, in an If packet of 512 bytes, 511 correct bytes are erased from the frame. Therefore, this paper proposed two kinds of upper layer decoding methods; LLR-based decoding and hybrid decoding. By means of simulation we show that the performance of the proposed decoding algorithm is superior to that of the conventional one.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.10
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• pp.1142-1149
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• 2007

In this paper, the development of wideband MIMO channel sounder and a pilot measurement result is described for research on the multi antenna radio propagation characteristics considering urban environment at microwave frequencies. We developed $4{\times}4$ MIMO(BW:100 MHz) channel sounder using the high speed switching mechanism and periodic pseudo random binary signals method considering next generation mobile communication system. A pilot measurement campaign at the urban area of Bundang is presented for confirmation of system performance. From the analysis of measurement data, wideband path loss exponent of 3.7 and 8 GHz band is 1.79 and 1.76. Average RMS delay spread is 200 ns and 42 ns respectively. From the experiment results, operation of this measurement system is confirmed considering research for a coverage, SNR and channel capacity in urban environment at microwave frequencies.

• The Journal of the Korea Contents Association
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• v.12 no.5
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• pp.103-112
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• 2012

This paper is based on the perspective that the YTN Science, a science channel in Korea which plays a key role in the popularization of science, is suffering from low viewing ratings, insufficient content, and shortage of production. First, this study employs an exploratory method to identify current status of programming and operation of the Korean science channel along with its promotional strategy. Second, it aims to conduct an analysis on the science channels, specifically some major programs, of other nations including the U.S. (Discovery Channel, National Geographic Channel), United Kingdom (BBC Knowledge), Japan (Science Channel), and China (CCTV 10), seeking the possibility to apply and combine them afterward to the Korean TV channels specialized in science. A number of implications are derived from our diagnosis of present situation and analysis of abroad cases, and this helps us suggest the content development and promotional strategies as follows: First, due to the rising need for change in the programming strategy to enhance the value of the content, it is required to rearrange the programming in terms of the target audience and the viewer lifestyle, adopt a new strategy for building up the viewers' watching habit through 'stripping', and place strategic programs in prime-time. Second, as for the specific schemes of content production and application, it is recommended to establish a dual strategy in creating the content (one for conveying knowledge, the other for delivering fun), plan and use a representative character of the program, select scientific and technological topics with more Korean backgrounds, attempt strategic ties with SNS, deepen and diversify the material for programs, and implement a strategy to boost the OSMU. Finally, with regard to the promotional strategy, a constructive proposal may include raising channel awareness through science-related events and live broadcasting, performing promotional strategies by way of expanding to printed media like magazine and book publications, and intensifying online and mobile promotional strategy.