• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.1
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• pp.100-113
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• 2018

The Proximity Service, which is one of the most popular network capacity improvement methods, uses the frequency reuse in order to increase the frequency efficiency. As a result, inter-cell interference between cellular and proximity service users occurs at a cell edge. In this paper, we proposed a mitigation scheme for inter-cell interference, where we suggested a new function of and eNB with ProSe function exchanging information about ProSe parameters and ProSe user equipment with neighboring cells via the X2 interface. As the first step, the resource which did not cause the inter-cell interference problem were pre-allocated through the frequency sensing in the ProSe direct discovery. As the next step, the inter-cell interference problem was solved by reallocating appropriate resources based on the ProSe application code, the ProSe application QoS, the ProSe application ID and validity timer in ProSe direct communication.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.126-129
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• 2015

Device-to-device (D2D) communications, a subset of Proximity-based Services that enables direct communication between LTE network subscribers, is gaining popularity. It is well underway to be adopted in cellular communication systems for pedestrian and connected-vehicles alike. In this paper, we briefly present our model of an Evolved Packet Core Network-assisted device discovery simulator and show the applicability of Proximity-based Services for Vehicular Ad-hoc Networks. Through the performance evaluation based on the developed simulation environment, it is shown that in case when users gather in the same vicinity, as in public transportation, LTE network data can be efficiently offloaded and multicasted through Wi-Fi for e.g. delivering traffic-related information and for the benefit of infotainment service consumers.

• 한국공간정보시스템학회:학술대회논문집
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• 2005.11a
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• pp.61-66
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• 2005

Spatiotemporal data mining represents the confluence of several fields including spatiotemporal databases, machine loaming, statistics, geographic visualization, and information theory. Exploration of spatial data mining and temporal data mining has received much attention independently in knowledge discovery in databases and data mining research community. In this paper, we introduce an algorithm Max_MOP for discovering moving sequences in mobile environment. Max_MOP mines only maximal frequent moving patterns. We exploit the characteristic of the problem domain, which is the spatiotemporal proximity between activities, to partition the spatiotemporal space. The task of finding moving sequences is to consider all temporally ordered combination of associations, which requires an intensive computation. However, exploiting the spatiotemporal proximity characteristic makes this task more cornputationally feasible. Our proposed technique is applicable to location-based services such as traffic service, tourist service, and location-aware advertising service.

• Electronics and Telecommunications Trends
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• v.30 no.1
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• pp.123-132
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• 2015

최근 근접 서비스(Proximity Service)에 대한 관심이 뜨거워지고 있다. 애플에서는 iBeacon을 출시하여, 근접 서비스 시장 생태계를 선점하려 하고 있으며, 퀄컴과 삼성도 발 빠르게 대응하고 있다. 국내 이동통신사업자인 SKT도 다양한 근접 서비스를 출시하고 있다. 근접 서비스란 사용자가 가까이 있음으로써 가능한 서비스로써 대표적으로 상용화되고 있는 것으로 근접 마케팅이 있다. 근접 서비스를 제공하기 위해서는 크게 3가지 기술을 활용할 수 있다. Wi-Fi Direct, 3GPP Prose 및 블루투스 저에너지 기술이 그것이다. 본고에서는 상기 기술들에 기반한 대표적인 근접 서비스 제공 사례를 통해 근접 서비스 동향을 파악하고 근접 서비스를 가능하게 하는 기술적인 원리에 대해 간략히 살펴보고자 한다.

• Korean Journal of Human Ecology
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• v.12 no.5
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• pp.713-735
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• 2003

The purpose of this study was to investigate the effects of the characteristics of maternal social networks on maternal expectation for their own children to examine the path that social networks had an effect on the self-esteem and the emotional intelligence of children through maternal expectation for their own children. The data used in this study were collected from 524 fourth to sixth graders and their mothers residing in Daejeon using structured questionnaire. The major findings of the study were as follows : (1) Among social network characteristics, proportion of friends and neighbors, proximity, direction and interference had a negative effect, and proportion of mothers of child's friends, frequency of contact, intimacy, emotional support, service support had a positive effect on maternal expectation for their own children. (2) Among social network characteristics, proportion of mothers of child's friends had a direct effect and proportion of friends, neighbors, and mothers of child's friends, proximity, frequency of contact, intimacy, direction, emotional support, service support, and interference had an indirect effect on children's emotional intelligence through maternal expectation for their own children. (3) Among social network characteristics, proportion of kin and mothers of child's friends, intimacy, service support, material support and interference had a direct effect, and proportion of neighbors and mothers of child's friends, proximity, frequency of contact, direction, service support had an indirect effect on children's emotional intelligence through maternal expectation for their own children.

• Journal of KIISE:Information Networking
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• v.31 no.6
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• pp.643-658
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• 2004

Mobile ad hoc networks(MANET) have recently attrarted a lot of attention in the research community as well as in industry. Although the previous research mainly focused on the various problems of MANET in data link and network layers, we consider, in this paper, how to efficiently support applications such as service discovery on top of MANET. Peer-to-Peer(P2P) overlay network can be adopted to service discovery mechanism because P2P and MANET share certain similarities, primarily the fact that both arc instances of self-organizing decentralized systems. Especially, distributed hash table(DHT) systems used for r2r overlay network can be effective in reducing the communication overhead in service discovery. However, since overlay network is independent of physical network topology and existing topology-aware mechanisms are based on the wired network, they are inefficient in MANET. We propose a proximity-based overlay network routing to overcome the inefficiency of routing in overlay network. In the proximity-based overlay network routing, each node collects information of physically close nodes by using one hop broadcast and routes messages to the logically closest node to destination. In a detailed ns-2 simulation study, we show that the proximity-based overlay network routing reduces the number of physical hops comparable to the flooding-based mechanism with low communication overhead. We also find that the proposed scheme works well in the mobile environment.

• Korean Business Review
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• v.19 no.1
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• pp.193-221
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• 2006

Customer Contact, defined as "the extent of interpersonal interaction between customer and service provider", is recognized as an important contributor to the perception of service quality, which in turn brings positive impacts on customer satisfaction, customer retention and loyalty especially in service contexts. The major purposes of this study are to explore the dimensionality of customer contact construct, to access the influences of customer contact dimensions on service quality dimensions, and to evaluate the relative importance of customer contact dimensions on service quality. Data from 388 customers of hotels at youngdong area in Kangwon-do were analyzed with major findings and their implications for service companies including hotels are as follows. First of all, the results of factor analysis show that customer contact is constructed with two dimensions, namely communication time and contact proximity. Secondly, overall customer contact is found to have positive effects on customers' perception of overall service quality and each dimension of customer contact has significant effects on overall service quality. Third, contact proximity dimension has relatively more important contributors than communication time has on overall service quality and four dimensions of service quality.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.10
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• pp.908-917
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• 2013

In this paper, we propose a discovery protocol for finding nearby mobile applications and services in a device-to-device communications system. The device-to-device communication technology enables proximity-based services such as mobile social networks and mobile marketing. For realizing these proximity-based services, it is essential to design a discovery protocol which pinpoints the devices with mobile applications of interest among hundreds and thousands of devices in proximity. In the infrastructure-less networks such as ad hoc networks, we can design the discovery protocol that periodically broadcasts a short discovery code containing the compressed information of the mobile applications. In this paper, we design the discovery protocol with the discovery code generated by using a hash function and a Bloom filter. We also mathematically analyze the performance of the proposed protocol.

• Information and Communications Magazine
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• v.30 no.12
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• pp.97-104
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• 2013

최근 스마트폰, 태블릿등과 같은 모바일 인터넷 기기들이 폭증함에 따라 Bluetooth 또는 WiFi P2P와 같은 기존 단말 간 통신 기술에 비해 넓은 전송 범위와 높은 QoS (Quality of Service)를 보장할 수 있는, 새로운 근접 서비스 기반(Proximity-based service)의 단말 간 (Device-to-device: D2D) 통신 기술에 대한 필요성이 대두되고 있다. 본 논문에서는 D2D 기술을 이용한 서비스 및 해당 서비스를 위한 요구사항들과 이를 지원하기 위한 요소기술들, 그리고 IEEE와 3GPP에서 활발히 진행되고 있는 D2D 통신 기술의 표준화 동향을 살펴보고자 한다.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.47 no.4
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• pp.105-111
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• 2010

This paper proposes the recursive algorithm for passive proximity detection system based on signal strength. The system is designed to be used in the smart medicine chest in order to provide location-based service for the senior personnel. Due to the system profile, single receiver and uni-direction communication are applied over the signal attenuation model for the determination of user existence within certain proximity. The performance of conventional methods is subjective to the sight between the transmitter and receiver unless the direction of target is known. To appreciate the temporal and spatial locality of human subjects, the authors present exponential moving average (EMA) to compensate the unexpected position error from the direction and/or environment. By using optimal parameter, the experiments with EMA algorithm demonstrates 32.26% (maximum 40.80%) reduction in average of the error probability with 50% of consecutive sight in time.