• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.7
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• pp.12-21
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• 2002

In this paper, we propose a new hybrid ARQ scheme to consider real-time and non real-time services in a wireless ATM network. Real-time and non-real-time services require different error control schemes according to each service characteristics. Therefore, in the next generation mobile communication environments where these service scenarios should be deployed, hybrid ARQ scheme using RCPC code with variable coding rate becomes one of the most suitable solutions. Because the variable coding rate is applied according to traits of transmitted frame and channel status, hybrid ARQ scheme using RCPC code can expect UEP effect. The UEP scheme does not apply equal error protection level to all information, but does high error protection level to more important information. In Our scheme, UEP of high error protection level is applied to real-time service, and UEP of low error protection and retransmission techniques are applied to non real-time service. We show that the proposed hybrid ARQ scheme improves channel utilization efficiency and yields high error correction behaviors.

• Journal of the Economic Geographical Society of Korea
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• v.11 no.1
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• pp.148-163
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• 2008

As with cities, all components of a campus must be carefully calibrated to provide the facilities, services like energy, water, electricity, information and communication; classrooms, libraries and laboratories for working; transportation networks and systems for movement of persons, goods, and services; athletic and other facilities for health and competition; places to eat, recreate and socialize; places to display and store works of arts; spaces for the performing arts' spaces for active assembly or solitary pondering. The goal of this study is how to observe the campus planning and development as a part in the context of the community. This study was taken into account neighborhood concerns and Harvard design guidelines. As an observer for the university's northern campus edge, this study suggests in the context of a long and sometimes turbulent history of dialogue and negotiations between Harvard University and first host community, Agassiz which is one of Cambridge's thirteen neighborhoods.

• The Journal of the Korea Contents Association
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• v.10 no.11
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• pp.58-67
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• 2010

Data-centric storage schemes(DCS) are one of representative researches that efficiently store and manage sensor readings in sensor nodes in the sensor networks. In DCS, a sensor sends the sensed data to a specific node in order to store them. However, it has a problem that sensor nodes consume a lot of energy for transmitting their readings to remote sensor node. In this paper, we propose a novel sensor data compression algorithm to reduce communication costs for DCS. The proposed algorithm establishes a safe region and transmits the sensed data only when current measurement is out of the safe region, As a result, the proposed algorithm extends network life time and reduces data transmission. It is shown through performance evaluation that our proposed algorithm reduces energy consumption by about 60% over the conventional algorithm.

• The Journal of the Korea Contents Association
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• v.10 no.2
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• pp.14-24
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• 2010

Because WSNs operate with limited resources of sensor nodes, its life is extended by cluster-based routing methods. In this study, we use data on direction, distance, density and residual energy in order to maximize the energy efficiency of cluster-based routing methods. Through this study, we expect to minimize the frequency of isolated nodes when selecting a new cluster head autonomously using information on the direction of the upper cluster head, and to reduce energy consumption by switching sensor nodes, which are included in both of the new cluster and the previous cluster and thus do not need to update information, into the sleep mode and updating information only for newly included sensor nodes at the setup phase using distance data. Furthermore, we enhance overall network efficiency by implementing secure and energy-efficient communication through key management robust against internal and external attacks in cluster-based routing techniques. This study suggests the modified cluster head selection scheme which uses the conserved energy in the steady-state phase by reducing unnecessary communications of unchanged nodes between selected cluster head and previous cluster head in the setup phase, and thus prolongs the network lifetime and provides secure and equal opportunity for being cluster head.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.6
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• pp.2709-2734
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• 2020

The growing demand to make wireless data services 5G compatible has necessitated the development of an energy-efficient approach for an effective new wireless environment. In this paper, we first propose a cognitive sensor node (CSN) based game theory for deriving energy via a primary user-transmitted radio frequency signal. Cognitive users' time was segmented into three phases based on a time switching protocol: energy harvest, spectrum sensing and data transmission. The proposed model chooses the optimal energy-harvesting phase as the effected factor. We further propose a distributed energy-harvesting model as a utility function via pricing techniques. The model is a non-cooperative game where players can increase their net benefit in a selfish manner. Here, the price is described as a function pertaining to transmit power, which proves that the proposed energy harvest game includes Nash Equilibrium and is also unique. The best response algorithm is used to achieve the green connection between players. As a result, the results obtained from the proposed model and algorithm show the advantages as well as the effectiveness of the proposed study. Moreover, energy consumption was reduced significantly (12%) compared to the benchmark algorithm because the proposed algorithm succeeded in delivering energy in micro which is much better compared to previous studies. Considering the reduction and improvement in power consumption, we could say the proposed model is suitable for the next wireless environment represented in 5G.

• Journal of Korea Spatial Information System Society
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• v.4 no.2 s.8
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• pp.23-34
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• 2002

Various tries are in progress to expand the usability of wireless telecommunication harminized internet technology. The most typical example among those services is LBS(Location Based Service). Nowaday, Standards for telecommunication system of LBS centers round on 3GPP(3rd Generation Partnership Project) and 3GPP2. In this paper we compare the telecommunication system of 3GPP and 3GPP2 in order to make domestic standards of telecommunication system to provide LBS. First, we investigate network models and interfaces of GSM(Global System for Mobile) and ANSI(America National Standard Institute)-41/PCS1900 - Telecommunication type of 2nd generation. Also we consider those of UMTS (Universal Mobile Telecommunication System) and cdma2000 - Telecommunication type of 3nd generation. Then we analysis function components for LBS of each network models details.

• Journal of Korea Society of Industrial Information Systems
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• v.13 no.4
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• pp.73-82
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• 2008

Collecting and managing the sensor information through the Internet is critical to effectively manage and utilize the sensor information. The interworking technique of the sensor network and internet is required to realize the desirable condition for managing and utilizing the sensor information. Among many interworking techniques, the translation technique using the gateway had been widely studied. However, the technique which mounts IP-based Internet protocols directly on the sensor node is getting more attention recently. Particularly, IPv6 is suitable for the communication protocol for the sensor network, because its features, such as abundant address space or address auto-configuration, are well matched with the sensor network. In this paper, we design the tiny UDP/IPv6 protocol functions which are suitable for the sensor network environment, and we implemented the functions with TinyOS based nesC. After we examined the simulation results of by using TOSSIM and TinyViz, we carried out the experimental performance evaluation for the program by mounting the tiny UDP/IPv6 on the sensor node (Mote).

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.12
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• pp.107-116
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• 2013

We proposed the WSN monitoring system applied the augmented reality to visualize effectively an indoor WSN. To implement system, we used wireless sensor network, indoor location determination, location-based augmented reality technology. First, we composed the wireless sensor networks indoors and implement web server and then get data from server DB using Android phones. Then, we obtained the (x, y) coordinates using the triangulation method from RSSI of three point of the strongest signal strength of the AP's. Also, we adjusted coordinates using the Kalman filter. Finally, we inserted the adjusted coordinates to the latitude and the longitude of the Mixare that use the GPS signal, and we got location of user and wireless sensor in the server DB. After that, we implemented augmented reality system using the android phone and wireless sensor location and data and real life image.

• Journal of IKEEE
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• v.13 no.3
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• pp.7-17
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• 2009

WiMedia UWB technology is a fully distributed data communication technology developed for the application demanding a high data transmission rate in the wireless PAN area. In general, devices can send data either by reserving time slots or by using prioritized CSMA/CA. If the PCA protocol of prioritized CSMA/CA is used, they are suffered congestion as the number of devices increases. In this paper, we propose a Deterministic Access Protocol(DAP) in WiMedia WPANs. A DAP is a method to transmit data in the non-reserved DRP period without competition as each device informs the beacon order information in the beacon period and the queue information. In addition, the problem that the devices with a lower beacon slot number have more transmission opportunities is addressed by introducing the reference point. Simulation results are given to demonstrate that a DAP can improve the throughput and reduce the packet loss rate.

• The Journal of the Convergence on Culture Technology
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• v.6 no.3
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• pp.233-244
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• 2020

We are exposed to video content and numerous information from digital signage such as convenience stores, coffee shops, restaurants, and elevators on buses and subways 365 days. However, so far, studies have focused solely on the technical effectiveness of digital signage or the consumer experience aspect of digital signage, and little has been done on the impact of teaser advertising on the intent of viewing. Through this study, we hope that the digital signage of convenience stores will develop into a differentiated digital signage area that provides diverse video content experiences to consumers and viewers and allows them to communicate, suggesting a direction as a research that shows that digital content (video) is now recognized as a product in an environment where demand for non-face-to-face and digital content is gradually increasing in 2020 after the global COVID 19.