• The KIPS Transactions:PartC
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• v.13C no.4 s.107
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• pp.415-426
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• 2006

The essential characteristic of ubiquitous is context-awareness, and that means ubiquitous computing can automatically process the data that change according to space and time, without users' intervention. However, in circumstance of context awareness, since location information is able to be collected without users' clear approval, users cannot control their location information completely. These problems can cause privacy issue when users access their location information. Therefore, it is important to construct the location information system, which decides to release the information considering privacy under the condition such as location, users' situation, and people who demand information. Therefore, in order to intercept an outflow information and provide securely location-based information, this paper suggests a new system based CS-RBAC with the existing LBS, which responds sensitively as customer's situation. Moreover, it accommodates a merit of PCP reflecting user's preference constructively. Also, through privacy weight, it makes information not only decide to providing information, but endow 'grade'. By this method, users' data can be protected safely with foundation of 'Role' in context-aware circumstance.

• Journal of Korea Multimedia Society
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• v.19 no.7
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• pp.1166-1178
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• 2016

In Internet of Things (IoT) environments, billions of interconnected devices and multimedia sensors generate a huge amount of multimedia traffic. Since the environment are in general deployed as a server-centric architecture wireless sensor networks could be bottlenecks between IoT gateways and IoT devices. The bottleneck causes high power consumption of the device and triggers very heavy network overload by transmission of sensing data. The deterioration could decrease the quality of multimedia streaming service due to delay, loss, and waste of device power. Thus, in this paper, we propose a context-based adaptive multimedia streaming scheme to support enhanced QoS and low power consumption in IoT environments. The goal of the scheme is to increase quality score per voltage of the streaming service, given an adaptation algorithm with context that are classified network and hardware such as throughput, RTT, and CPU usage. From the both context, the quality score per voltage is used in the comparison of a only network context-based adaptive multimedia streaming scheme, a fixed multimedia streaming and our scheme. As a result, we achieves a high improvement that means the quality score per voltage is increased up to about 4, especially in case of resolution change.

• Journal of Korean Elementary Science Education
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• v.37 no.1
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• pp.39-53
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• 2018

The purpose of this study was to investigate the conceptual structure of subjects related to matter having pre-service elementary school teachers by applying semantic network analysis (SNA). The analyzed concepts in the subjects of matter were 6 words such as 'atom', 'molecule', 'ion', 'electron', 'matter' and 'particle'. The results of SNA of the concepts are as follows : 1. In the semantic network of 'atom', words having a high betweenness centrality were linked with the words based on both the scientific context and the everyday context. 2. The network of 'molecule' was analyzed to be more organized than the network of the 'atom'. 3. In the network of 'ion', the group of words of the scientific context was distinguished from the group of words of the everyday context. 4. The network of 'electron' was analyzed to be more oriented on electricity and magnetism in the field of physics. 5. In the network of 'matter', the words related to compounds were linked with knowledge of history of science. 6. The network of 'particle' was not structured with words based on particulate nature of matter.

• Journal of Korea Multimedia Society
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• v.11 no.2
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• pp.214-227
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• 2008

As cellular network technologies continue to evolve, various network standards coexist in most CDMA-based cellular networks. This means that mobile device users access mobile services over different network bandwidths according to the users' positions or the mobile devices' network access capabilities. Such differences of network bandwidths cause big differences in service response times. To address this problem, we present a framework called CANS (Context-Aware framework for mobile Navigation Services), which takes into account the user's network profile to adapt the contents for CDRG(Centrally Determined Route Guidance) navigation services for cellular phones. To the best of the authors' knowledge, CANS is the first context-aware framework to make mobile navigation services more feasible. The experimental results under commercial CDMA network show that CANS is able to provide similar service response times regardless of type of wireless network to which users connect by adapting the contents to network bandwidths.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.5
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• pp.486-494
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• 2014

Intelligent homes consist of ubiquitous sensors, home networks, and a context-aware computing system. These homes are expected to offer many services such as intelligent air-conditioning, lighting control, health monitoring, and home security. In order to realize these services, many researchers have worked on various research topics including smart sensors with low power consumption, home network protocols, resident and location detection, context-awareness, and scenario and service control. This paper presents the real-time metabolic rate estimation method that is based on measured heart rate for human adaptive appliance (air-conditioner, lighting etc.). This estimation results can provide valuable information to control smart appliances so that they can adjust themselves according to the status of residents. The heart rate based method has been experimentally compared with the location-based method on a test bed.

• Journal of Intelligence and Information Systems
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• v.11 no.3
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• pp.1-23
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• 2005

Personalized reminder systems have to identify the user's current needs dynamically and proactively based on the user's current context. However, need identification methodologies and their feasible architectures for personalized reminder systems have been so far rare. Hence, this paper aims to propose a proactive need awaring mechanism by applying agent, semantic web technologies and RFID-based context subsystem for a personalized reminder system which is one of the supporting systems for a robust ubiquitous service support environment. RescorlaWagner model is adopted as an underlying need awaring theory. We have created a prototype system called NAMA(Need Aware Multi-Agent)-RFID, to demonstrate the feasibility of the methodology and of the mobile settings framework that we propose in this paper. NAMA considers the context, user profile with preferences, and information about currently available services, to discover the user's current needs and then link the user to a set of services, which are implemented as web services. Moreover, to test if the proposed system works in terms of scalability, a simulation was performed and the results are described.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.11
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• pp.1323-1330
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• 2014

As for civil service support, the interaction between citizens as well as the government and citizens has an important value, and the participation between citizens be very important. The interaction between these citizens can lead to spreading the use of the app by getting them to share their status information with an specified number of people in the public service such as a social network service. Mobile-based social network service has various built-in sensors to increase the interaction between the government and citizens and post the status information of users on SNS. In this regard, this paper proposed a social network application for civil services based on the Android by using location-based context information. Experimental results showed that since the application proposed in this paper can be applied to low-performance system and exhibits high performance, it can allow users located at a short distance to detect new information and share contents by adding the content to SNS which is the closest to the location of users.

• KIPS Transactions on Software and Data Engineering
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• v.5 no.2
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• pp.59-68
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• 2016

Context-aware services recognize the context of situation environments of users and provide useful services according to the context for users. Usual rule-based systems can be used for context-aware services with the specified rules that express context information and operations. This paper proposes a light-weight rule engine that minimizes memory consumption for resource-constrained smart things. The rule engine manages rules at the minimum condition level, removes memories for intermediate rule matching results, and uses hash tables to store rules and context information efficiently. The implemented engine is verified using a rule set of a mouse training system and experiment results shows the engines consumes very little memory compared to the existing Rete algorithm with some sacrifice of execution time.

• Archives of design research
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• v.17 no.3
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• pp.403-412
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• 2004

Ubiquitous computing will bring on comprehensive changes of environment. We need to understand how this change will change human life and what will be needed in this circumstances. Then we have to develope the appropriate sonics in ubiquitous computing environment. The design of ubiquitous computing environment has the concept of designing human life. Thus to develope the scenarios which are able to predict human life is to make a foundation of developing design concepts effectively. However there is a gap due to the lack of the dear methodology between the analyzing trend of technology and the process of estimating the future life and developing the service scenarios. So, most of the scenarios which have developed up to now do not present the service that exactly reflects all the complicated and pluralistic sides of environment. The service in the ubiquitous computing environment should take the form of grasping the user's context and offering the information with the most adequate way. Therefore we have to know when they need services, where they use services and what kind of services they want. It means that we should understand the life and the environment of user clearly and wholly with the prospect of developing service. We also need the method for developing UC(ubiquitous computing) service based on this. This study focuses on the future family life and analyzes the user's context from a point of view of service development and in this ground, we have progressed the research about the methodology to develop the UC service scenario for suggesting the service. Through the applying of this methodology, we could analyze the user's context systematically and could make the best use of the analyzed data for proposal service idea. And the UC service scenarios which reflect future life on the basis of various use's context could be developed.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.11
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• pp.2016-2034
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• 2011

Ubiquitous Healthcare (u-Healthcare) is the intelligent delivery of healthcare services to users anytime and anywhere. To provide robust healthcare services, recognition of patient daily life activities is required. Context information in combination with user real-time daily life activities can help in the provision of more personalized services, service suggestions, and changes in system behavior based on user profile for better healthcare services. In this paper, we focus on the intelligent manipulation of activities using the Context-aware Activity Manipulation Engine (CAME) core of the Human Activity Recognition Engine (HARE). The activities are recognized using video-based, wearable sensor-based, and location-based activity recognition engines. An ontology-based activity fusion with subject profile information for personalized system response is achieved. CAME receives real-time low level activities and infers higher level activities, situation analysis, personalized service suggestions, and makes appropriate decisions. A two-phase filtering technique is applied for intelligent processing of information (represented in ontology) and making appropriate decisions based on rules (incorporating expert knowledge). The experimental results for intelligent processing of activity information showed relatively better accuracy. Moreover, CAME is extended with activity filters and T-Box inference that resulted in better accuracy and response time in comparison to initial results of CAME.