• Proceedings of the Korea Information Processing Society Conference
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• 2011.11a
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• pp.177-180
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• 2011

In practice, it is well known that geographical and/or location based routing is highly effective for wireless sensor network. Here, electing some landmarks on the network and forwarding data based on the landmark is one of the good approaches for a vast sensing field with holes. In the most previous works, landmarks are elected without considering the residual energy on each sensor. In this paper, we propose an Energy aware Landmark Election and Routing (ELER) protocol to establish a stable routing paths and reduce the total power consumption. The proposed protocol makes use of each sensor's energy level on electing the landmarks, which would be utilized to route a packet towards the target region using greedy forwarding method. Our simulation results illustrate that the proposed scheme can significantly reduce the power dissipation and effectively lengthen the lifetime of the network.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.05a
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• pp.40-43
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• 2008

This paper describes a Grid-based context-aware doctor recommender system which recommends appropriate doctors for a patient or user at the right time in the right place. The core of the system is a recommendation mechanism that analyzes a user's demographic profile, user's current context information (i.e., location, time, and weather), and user's position so that doctor information can be ranked according to the match with the preferences of a user. The performance of our architecture is evaluated compare to centralized recommender system.

• The Journal of the Korea Contents Association
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• v.18 no.1
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• pp.64-75
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• 2018

With the development of location-aware technologies and the activation of smart phones, location based social networks(LBSN) have been activated to allow people to easily share their location. In particular, studies on recommending the location of user interests by using the user check-in function in LBSN have been actively conducted. In this paper, we propose a location recommendation scheme considering time and user activities in LBSN. The proposed scheme considers user preference changes over time, local experts, and user interest in rare places. In other words, it uses the check-in history over time and distinguishes the user activity area to identify local experts. It also considers a rare place to give a weight to the user preferred place. It is shown through various performance evaluations that the proposed scheme outperforms the existing schemes.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.4
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• pp.665-683
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• 2011

Wireless sensor networks (WSN) consist of a large amount of sensor nodes distributed in a certain region. Due to the limited battery power of a sensor node, lots of energy-efficient schemes have been studied. Clustering is primarily used for energy efficiency purpose. However, clustering in WSNs faces several unattained issues, such as ensuring connectivity and scheduling inter-cluster transmissions. In this paper, we propose a location-based spiral clustering (LBSC) algorithm for improving connectivity and avoiding inter-cluster collisions. It also provides reliable location aware routing paths from all cluster heads to a sink node during cluster formation. Proposed algorithm can simultaneously make clusters in four spiral directions from the center of sensor field by using the location information and residual energy level of neighbor sensor nodes. Three logical addresses are used for categorizing the clusters into four global groups and scheduling the intra- and inter-cluster transmission time for each cluster. We evaluated the performance with simulations and compared it with other algorithms.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.7
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• pp.1715-1722
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• 2010

In this paper we consider methods for selecting the next tracing node that take advantage of the history of traced positions during the packet-tracing. In the meantime, the proposed routing strategy that counters the tracing is to design the routing path is such a way that nodes on it are not close to the nodes whose location privacy is needed and zigzag or back-and-forth movements hardly take place. In simulations, the ratios of successful tracing were largely improved. It was shown that our routing scheme allows more data packets to be delivered to the destination while, enticing the tracer to move more long distances in the presence of multiple assets.

• The Journal of the Korea Contents Association
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• v.7 no.7
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• pp.153-160
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• 2007

Be new, and various service is created through Ubiquitous Computing and Ubiquitous networks. Specially, recognize a situation of the object like a person and things, and Ubiquitous Location Based Services(u-LBS) to provide service to be useful to early bases is coming wherever to the front by important service when. This papers developed eCRM Mobile Marketing System. This Mobile Marketing System for the eCRM which they developed used location based in order companies currently used eCRM, and to more efficiently do customer Marketing.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.9 no.3
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• pp.198-205
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• 2009

In this paper, design of framework architecture of pervasive computing system providing seamless inter space interactions between private and public smart spaces is presented. The seamless inter space interaction issues are related to establishing user's service environment by allocating relevant resources in a new location where there are no prior settings for the user or where there are current users already being served in the new location. In the realm of pervasive computing, we can have different types of smart spaces, offering proactive and intelligent services, which are islands of smart spaces independent from each other. As users move about, they will have to roam from private smart space to public smart space and vice versa. When they enter a new island of smart space, they will have to setup their devices and service manually to get the same or different services they had at the previous location. Users might be living in a non-pervasive computing environment because this manual operation is inappropriate to its generic features of proactive and intelligent services of pervasive computing. The framework architecture will provide seamless inter space interactions initiated by changes in users' location to acquire negotiations of resources for new and current residents regarding service provision with limited available networked devices.

• The KIPS Transactions:PartD
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• v.17D no.1
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• pp.53-58
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• 2010

This research aims to develop practical location-based services that provide users with personalized theater guide services on smart phones. In this research, we have designed and implemented a smart theater guide system for Deahakro, Seoul based on smart phones incorporating GPS. This system first identifies the current position using GPS, and maps the current position onto the map. It is designed and implemented to provide users with personalized information service about the plays and the theaters nearby the current position. It is also optimized to be useful effectively by performing on-site experiments.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.3
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• pp.127-135
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• 2015

Context-aware mobile cloud computing is a new promising paradigm that allows to improve user experience by analyzing contextual information such as user location, time of the day, neighboring devices and current activity. In this paper we provide performance study of context-aware mobile cloud computing system with Volare middleware. Volare monitors the resources and context of the device. and dynamically adapts cloud service requests accordingly, at discovery time or at runtime. This approach allows for more resource-efficient and reliable cloud service discovery, as well as significant cost savings at runtime. We also have studied the performance of context-aware mobile cloud computing for different quality of service (QoS) adaptation policies. Our simulations results show that when battery level is low and CPU usage is high and user cannot maintain the initial QoS, service cost is decreased according to current adaptation policy. In conclusion, the current adaptation policy suggested in this paper may improve user experience by providing a dynamically adapted service cost according to a situation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.10A
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• pp.960-967
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• 2006

Mobile communication is evolving toward next generation system that is capable to provide ubiquitous human-centric services with giving no restriction on time and location. In particular, context-awareness will be realized using various sensors and devices and related technologies under the ubiquitous Next Generation (NG) mobile communications environment where user's demand and surrounding context are changing dynamically. By such context awareness, context aware service which provides best suitable services for a user by analyzing user's needs and situational information, will be one of the promising NG mobile services. In this article, we propose NG mobile service environment with focusing on generic service traffic flows supported by the NG service platform which gives various means of connecting users and service providers. Then, we propose evolutional phases of context-aware services based on ranges of context information and evolutional trend of telecommunication technologies and networking environment in NG mobile service environment.