• Journal of the Korean BIBLIA Society for library and Information Science
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• v.22 no.1
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• pp.171-191
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• 2011

The purpose of this study is to introduce the concepts of smartphone and app, to review the theoretical researches and the representative service examples in academic libraries' mobile services based on smartphone apps, and to propose the proper mobile services methods based on smartphone apps in academic libraries of Korea. The ways for mobile app services in academic libraries are like these: 1) Libraries need to prepare the hybrid service system based on the combination of mobile web and app for smartphone. 2) Libraries have the guidelines for choosing apps which are applied to library services. 3) Libraries develop the apps for library marketing and education services and make use of existed apps to their own services. 4) Smartphone application bibliography service(Appography service) needs to be developed and serviced as an academic library service field.

• Journal of Korea Multimedia Society
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• v.7 no.12
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• pp.1719-1728
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• 2004

The fusion of Internet technology and applications with wireless communication provides a new business model and promises to extend the possibilities of commerce to what is popularly called mobile commerce, or m-commerce. In mobile Internet banking service through wireless local area network, security is a most important factor to consider. We describe the development of security service for mobile Internet banking on Personal Digital Assistants (PDAs). Banking Server and Authentication Server were developed to simulate banking business and to support certificate management of authorized clients, respectively. To increase security, we took hybrid approach in implementation: symmetric block encryption and public-key encryption. Hash function and random number generation were exploited to generate a secret key. The data regarding banking service were encrypted with symmetric block encryption, RC4, and the random number sequence was done with public-key encryption. PDAs communicate through IEEE 802.IIb wireless LAN (Local Area Network) to access banking service. Several banking services and graphic user interfaces, which emulatedthe services of real bank, were developed to verity the working of each security service in PDA, the Banking Server, and the Authentication Server.

• Journal of Distribution Research
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• v.11 no.1
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• pp.99-124
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• 2006

The purposes of the study are two-folds. First, it analyzes how factors other than price(e.g. delivery service, saving point policies, free gifts) impact total price for various products and different types of stores. Second, it analyzes how to increase market efficiencies through price level, price differences, and the frequency of price changes for different shops, various products and different types of transactions. By analyzing the price level within different types of stores, there found that prices at on-line store were lower than off-line shops. It also found price differences between pure on-line, hybrid, and off-line store. Comparing prices by product size, there found that pure on-line shops have a lower price compared to others. The results showed that on-line store had lower price variation compared to off-line shops. When comparing pure on-line store to hybrid store, hybrid store had lower price variation. In terms of the frequency of price changes, hybrid stores had higher price fluctuations. In terms of total price differences for delivery distances, pure on-line store had great price fluctuation, excluding cosmetic goods. In conclusion, if we consider price level and price fluctuations, on-line store had more efficiencies and was superior in terms of price effectiveness. Hybrid shops, on the other hand, had greater advantages for seasonal goods and dominant products. Therefore, market entry strategies should differ based on order quantity, type of store(pure on-line, hybrid, off-line), product characteristics(seasonality, product life), etc.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.6 s.348
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• pp.39-45
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• 2006

n a hybrid ad-hoc network, wired network and a mobile ad-hoc network are connected by the internet gateway. To provide seamless service for internet users in the hybrid ad-hoc network, an efficient internet gateway selection technique and a fast handover technique are needed. In this paper, we propose a seamless handoff technique for providing mobility of mobile hosts in hybrid ad-hoc networks. The proposed internet gateway re-registration algorithm improves general handoff performance. Moreover, the handoff processing time within certain range of area is reduced by using mobility management agent(MMA). In addition the packet loss is reduced when handoff occurs out of the range of MMA by tunneling technique.

• Journal of the Korea Institute of Building Construction
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• v.16 no.3
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• pp.279-288
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• 2016

The fundamental performance of any construction material should cover at least two phases: safety and serviceability. Safety commonly represents adequate strength, while serviceability encompasses the control of cracking and deflections at service loads. With respect to rapid hydraulic binders as a construction material, the above two phases should also be considered. Recent research on rapid cooling ladle furnace slag (RC-LFS) has drawn much attention, particularly given that it shows remarkable rapid hydraulic ability to pulverize to a fineness of $6,300cm^2/g$. This industrial byproduct could contribute to developing the sustainability of the rapidly hardening cementitious material system. This paper aims to expand upon the applicability of an RC-LFS-based binder that is composed of two parts. It also seeks to illustrate the engineering performance of an RC-LFS-based hybrid fiber-reinforced composite and to increase the strength of the RC-LFS-based composite. Each step of this experiment followed ASTM standards. The engineering performance, in both fresh state and hardening state, was tested and discussed in this paper. According to the experimental results for fresh concrete, the air content increased following the addition of polypropylene fiber. For hardened concrete, the toughness and strength improved following the addition of a hybrid fiber. The hybrid fiber mixture, which contains 0.75% of steel fiber and 0.25% of polypropylene fiber, shows even better engineering performance than other mixtures.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.3
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• pp.73-81
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• 2020

Today's massively multiplayer online games(MMOGs) can contain millions of synchronous players scattered across the world and participating with each other within a single shared game. The increase in the number of players in MMOGs has led to some issues with the demand of server which generates a significant increase in costs for the game industry and impacts to the quality of service offered to players. In dealing with a considerable scale of MMOGs, we propose a cloud computing and peer-to-peer(P2P) hybrid architecture in this paper. Given the two nearly independent functionalities of P2P and cloud architectures, we consider the possibility of fusing these two concepts and researching the application of the resultant amalgamation in MMOGs. With an efficient and effective provisioning of resources and mapping of load, the proposed hybrid architecture relieves a lot of computational power and network traffic, the load on the servers in the cloud while exploiting the capacity of the peers. The simulation results show that MMOGs based on the proposed hybrid architecture have better performance and lower traffic received compared with MMOGs based on traditional client-server system.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.5
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• pp.454-462
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• 2016

portable white space device(WSD) obeying the Korean regulations of TV white space(TVWS) can cause harmful interference to a digital TV receiver residing at the same pixel around the edge of the digital TV service coverage for the case with a changed propagation environment. In order to solve this problem, we propose a method to allocate the resource of a hybrid WSD based on TVWS geo-location DB with spectrum sensing. Using the received power of digital TV signal through the spectrum sensing, a hybrid WSD can calculate the maximum permitted EIRP based on location probability. Based on the accurate allocation method proposed in this paper, it is possible to satisfy the Korean TVWS regulations and to eliminate the harmful interference to TV receivers nearby the hybrid WSD.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.10B
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• pp.630-638
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• 2005

As real-time media applications based on IP multicast networks spread widely, the end-to-end QoS (quality of service) provisioning for these applications have become very important. To guarantee the end-to-end QoS of multi-party media applications, it is essential to monitor the time-varying status of both network metrics (i.e., delay, jitter and loss) and system metrics (i.e., CPU and memory utilization). In this paper, targeting the multicast-enabled AG (Access Grid) group collaboration tool based on multi-Party real-time media services, a hybrid monitoring scheme that can monitor the status of both multicast network and node system is investigated. It combines active monitoring and passive monitoring approaches to measure multicast network. The active monitoring measures network-layer metrics (i.e., network condition) with probe packets while the passive monitoring checks application-layer metrics (i.e., user traffic condition by analyzing RTCP packets). In addition, it measures node system metrics from system API. By comparing these hybrid results, we attempt to pinpoint the causes of performance degradation and explore corresponding reactions to improve the end-to-end performance. The experimental results show that the proposed hybrid monitoring can provide useful information to coordinate the performance improvement of multi-party real-time media applications.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.2
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• pp.155-164
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• 2013

Two design techniques for more accurate and more convenient hybrid positioning system with visible light communication (VLC) and ad-hoc wireless network infrastructure are proposed, in order to overcome the problems of high estimation error, high cost, and limited service range of the conventional positioning techniques. First method is based on a non-carrier VLC based hybrid positioning technique for applications involving of low data rate optical sensing and narrow-range visible light reception from transmitter, and long-range positioning. The second method uses a 4 MHz carrier VLC-based hybrid positioning technique for a high data rate optical sensing and wide-range visible light receiving from transmitter, and mid-range positioning applications. In indoor environments with obstacles where there are long-range 7731.4cm and mid-range 2368cm distances between an observer and a target respectively, the hybrid positioning developed with two design techniques are tested, and the proposed system is verified and analyzed in this paper.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2016.06a
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• pp.288-291
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• 2016

디지털 라디오 수신 환경에서 권역을 이동하거나 수신 신호가 미약한 구간 특히 실내로 이동을 하고자 할 경우 서비스를 자동으로 연계해 줄 수 있는 서비스 연계(service following) 기술이 필요하다. 본 논문에서는 하이브리드 라디오 환경에서 자동으로 서비스 연계가 가능한 방법을 제안하고자 한다. 구체적으로는 서비스 연계 이벤트가 발생할 경우 연계 대상을 단말에서 결정하는 것이 아니라 인터넷 상에 이를 처리할 수 있는 서버를 두어 청취자로부터 전달되는 위치 좌표를 포함한 관련 방송 파라미터를 제공받아 가장 적합한 연계 대상을 식별한 후 이를 다시 단말에 제공하는 방식이다.