• 한국IT서비스학회지
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• 제14권4호
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• pp.257-267
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• 2015

We propose a vehicle-mounted, location-aware mobile digital signage system that can be used for public transportation through mobile communication. This paper proposes the installations of the LED display panels at the backside of the bus., which display traffic information to cars behind the bus. Information to be displayed would include, but is not limited to, road information, public commercials and private commercials. We propose the system architecture and further implement the prototype of mobile digital signage system for demonstration. The system is based on the Client-Server system. Each bus has a client terminal which detects the current location by a GPS receiver and sends its location information to the server using mobile communication function. The terminal device receives advertisements and traffic information from the server and displays it to the large LCD or LED panel installed at the inside and outside of the bus. We use the Android smartphone as a client system, which inherently equipped with GPS and mobile communication function. GPS detects the location of bus and reports its geo-location data to the traffic information center server via a wireless communication network. On the server side, we developed a specially designed control server, where it communicates with the other traffic information center and updates and manages the databases contents being displayed by each position. The server contains location dependent variable information and returns selected information back to the vehicle in real time. Spatial database is used to process location based data. Server system periodically receives the real time traffic information from the road information center database. And it process the information by bus location and bus line number. In this paper, we propose a mobile digital signage service and explain the system implementation of this service.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2013년도 춘계학술대회
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• pp.575-577
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• 2013

WiFi 무선 통신 기능을 갖춘 스마트폰을 비롯한 각종 가전 도구들이 시장에서 일반화되면서 WiFi AP(access point)를 통해서 무선 랜을 구축하고자 하는 수요가 증가하고 있다. 또한 최근 들어 AP의 가격이 저렴화 되면서 AP를 이용하여 주차 위치를 알려주는 등 다양한 서비스를 제공하려는 시도들이 생겨나고 있다. 본 논문에서는 제어 기능과 위치 정보 제공 기능을 갖춘 AP를 기반으로 하는 제어 시스템을 개발한다. 제안하는 제어 시스템은 외부 장치 제어 기능과 스마트폰 위치 확인 기능이 있는 AP와 AP들을 제어하고 수집된 정보들을 처리하는 AP 서버, 사용자들에게 서비스를 제공하기 위한 스마트폰용 응용 프로그램으로 구성된다.

• 한국공간정보시스템학회 논문지
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• 제11권3호
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• pp.19-30
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• 2009

최근 PDA, 휴대폰, GPS와 같은 모바일 기기 및 무선 통신 기술의 발달로 인하여 위치 기반 서비스의 이용이 확산되었다. 하지만 이러한 서비스는 사용자의 정확한 위치정보를 가지고 LBS 서버에 연속적으로 서비스를 요청하기 때문에, 심각한 개인 정보 누출의 위협이 될 수 있다. 따라서 모바일 사용자의 안전하고 편리한 위치기반 서비스 사용을 위한 개인 정보 보호 방법이 필요하다. 이를 위해 본 논문에서는 연속적인 위치기반 서비스를 지원하는 그리드 기반 Cloaking 영역 설정 기법을 제안한다. 제안하는 기법은 연속적인 위치기반 서비스를 효율적으로 지원하기 위하여 그리드 기반의 셀 확장을 통해 빠르게 Cloaking 영역을 설정한다. 아울러, 모바일 사용자의 위치 노출 확률을 최소로 하는 Cloaking 영역 설정을 위하여, 가중치를 부여하여 프라이버시 보호 수준을 계산한다. 마지막으로 성능평가를 통해서 제안하는 기법이 서비스 시간, 프라이버시 보호 수준에서 기존 연구보다 우수함을 보인다.

• 한국멀티미디어학회논문지
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• 제17권8호
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• pp.946-952
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• 2014

Mobility prediction is one of hot topics using location history information. It is useful for not only user-level applications such as people finder and recommendation sharing service but also for system-level applications such as hand-off management, resource allocation, and quality of service of wireless services. Most of current prediction techniques often use a set of significant locations without taking into account possible location information changes for prediction. Markov-based, LZ-based and Prediction by Pattern Matching techniques consider interesting locations to enhance the prediction accuracy, but they do not consider interesting location changes. In our paper, we propose an algorithm which integrates the changing or emerging new location information. This approach is based on Active LeZi algorithm, but both of new location and all possible location contexts will be updated in the tree with the fixed depth. Furthermore, the tree will also be updated even when there is no new location detected but the expected route is changed. We find that our algorithm is adaptive to predict next location. We evaluate our proposed system on a part of Dartmouth dataset consisting of 1026 users. An accuracy rate of more than 84% is achieved.

• 한국정보통신학회논문지
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• 제18권1호
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• pp.50-56
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• 2014

최근 위치 기반 서비스를 사용하는 안드로이드 앱이 널리 사용되고 있다. 안드로이드 플랫폼에서 지원되는 여러 위치 제공자 중 GPS (Global Positioning System) 위치 제공자의 동작에 대한 이해는 관련 안드로이드 개발자에게 중요한 과제이다. 본 고는 안드로이드 플랫폼의 GPS 서브시스템 소스를 분석하여, GPS 위치 제공자의 동작을, 주요 쓰레드를 중심으로 그리고 초기화 단계부터 최종 위치 보고 단계까지 단계별로 일목요연하게 제시하고자 한다.

• 한국IT서비스학회지
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• 제20권6호
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• pp.83-95
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• 2021

In this study, various usage patterns were analyzed after establishing a data mart for micro mobility analysis based on the rental history of public bicycles in Seoul. Rental history data is origin-destination data that includes the rental location and time, and the return location and time. About 1500 rental locations were classified according to the characteristics of the location to create a 'station type' dimension. We also created a 'path type' dimension that displays whether the rental location and return location are the same. In addition, a derived variable called speed, which is obtained by dividing the distance used by the time used, is added, and through this, the characteristics of the riding area and the reason for the rental can be estimated. Meanwhile, administrative district link, administrative neighborhood link, and station type link were created to apply network analysis. Through this analysis, the roles and proportions of administrative districts, public facilities, and private facilities engaged in micro-mobility services were visualized. 49.9% of rentals occur at rental offices near transportation facilities, and half of them occur at rental offices near subway stations. The number of rentals during the evening rush hour is more than double that of the morning rush hour. When the path type is unidirectional, there is a fixed destination, so the distance and time used are short, and the movement speed tends to be high. In the case of round-trip, the purpose of use is exercise or leisure, so the distance and time used are long, and the movement speed is slow. It is expected that the results of the analysis can be used as reference materials for selecting new rental locations, providing convenient services for users, and developing user-specialized products.

• 인터넷정보학회논문지
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• 제10권5호
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• pp.13-26
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• 2009

유비쿼터스 사회에서 u-서비스를 구현하기 위한 핵심기술 중의 하나인 무선센서네트워크는 대규모망에서 관리가 어렵고 안정성 및 이동성이 취약하다는 단점을 가진다. 이러한 문제점을 해결하기 위하여 최근 센서네트워크와 IP망과의 연동을 위한 6LoWPAN에 대한 연구가 활발히 진행 중에 있다. 본 논문에서는 6LoWPAN을 이용한 위치 추적 시스템 LTSGM(Location Tracking Service Based on Google Map)을 제안한다. LTSGM 시스템은 IP 인프라 서비스인 구글맵과 연동하여 센서노드의 위치를 시각적으로 제공함으로써 대규모 센서네트워크에서의 유지, 보수, 관리를 보다 용이하게 한다. 또한 모바일노드의 위치를 추적할 수 있으므로 향후 각종 재난, 범죄 등의 응용서비스에 활용될 수 있을 것으로 기대한다. 본 논문에서 구현한 LTSGM 시스템은 향후 6LoWPAN연구를 위한 시험적인 플랫폼이 될 수 있을 것이다.

• International Journal of Internet, Broadcasting and Communication
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• 제14권3호
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• pp.22-29
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• 2022

Recently, with the development of mobile computing power, mobile-based VR and AR services are being developed. Due to network performance and computing power constraints, VR and AR services using large-capacity 3D content have limitations. A study on an efficient 3D content load method for a mobile device is required. The conventional method downloads all 3D content used for AR services at the same time. In this paper, we propose an active 3D content load according to the user's track. The proposed method is a partitioned 3D object load. Edge servers were installed for each area and connected through the MESH network. Partitioned load the required 3D object in the area referring to the user's location. The location is identified through the edge server information of the connected AP. The performance of the proposed method and the conventional method was compared. As a result of the comparison, the proposed method showed a stable Mobile AR Service. The results of this study, it is expected to contribute to the activation of edge server-based AR mobile services.

• 제어로봇시스템학회논문지
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• 제12권9호
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• pp.905-911
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• 2006

Smart homes are expected to offer various intelligent services by recognizing the residents' life pattern, health, and feeling. One of the key issues for realizing the smart home is how to detect the locations of residents. Currently, the research effort is focused on two approaches: terminal-based and non-terminal-based method. The terminal-based method employs a type of device that should be carried by the resident while the non-terminal-based method has no such device. This paper presents a novel non-terminal-based approach using an array of pyroelectric infrared sensors (PIRs) that can detect residents. The feasibility of the system is evaluated experimentally on a test bed.

• ETRI Journal
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• 제29권2호
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• pp.169-178
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• 2007

With the advent of ubiquitous computing environments, it has become increasingly important for applications to take full advantage of contextual information, such as the user's location, to offer greater services to the user without any explicit requests. In this paper, we propose context-aware active services based on context-aware middleware for URC systems (CAMUS). The CAMUS is a middleware that provides context-aware applications with a development and execution methodology. Accordingly, the applications based on CAMUS respond in a timely fashion to contextual information. This paper presents the system architecture of CAMUS and illustrates the content recommendation and control service agents with the properties, operations, and tasks for context-aware active services. To evaluate CAMUS, we apply the proposed active services to a TV application domain. We implement and experiment with a TV content recommendation service agent, a control service agent, and TV tasks based on CAMUS. The implemented content recommendation service agent divides the user's preferences into common and specific models to apply other recommendations and applications easily, including the TV content recommendations.