• Journal of Software Engineering Society
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• v.24 no.1
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• pp.19-26
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• 2011

Since smart phones have various embedded sensors and high portability/usability, they have emerged as suitable targets to collect information and to provide intelligent services. That is, with a smart phone, we can collect information about user's circumstances and phone usage from sensors and infer his/her current state which is the significant basis for context-aware services. However, a service system should be founded on a context model to ensure reasonable context-awareness, because context information the system needs depends on its target services. Therefore, in this paper, we propose a hierarchical mobile context model for context inference of smart phone users in their daily life. We classify high-level context which can be draw from sensing data into three levels, Context-Behavior-Situation, and define inference methods for each level. With our mobile context model, we can user's meaningful context in his/her daily life besides simple actions or states.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.48 no.4
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• pp.9-20
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• 2011

Future warfare paradigm is changing to network-centric warfare and effects-based operations. In order to find first and strike the enemy in the battlefield, friendly unit requires real-time target acquisition, intelligence collection, accurate situation assessment, and timely decision. The rapid development in advanced sensor technology and wireless networks requires a significant change in operational concepts of the battlefield surveillance. In particular, the introduction of a battlefield surveillance sensor network system is a big challenge to the ground forces which have lack of automated information collection assets. Therefore this paper proposes an ontology-based context-aware framework for the battlefield surveillance sensor network system which is needed for early finding the enemy and visualizing the battlefield in the ground force operations. Compared with the performance of existing systems, the one of the proposed framework has shown highly positive results by applying the context systems evaluation method. The framework has also proven to be satisfactory by the structured evaluation method using device collaboration. Since the proposed ontology-based context-aware framework has a lot of advantages in terms of scalability and reusability, the ground force's reconnaissance and surveillance system can be widely applied to expand in the future. And, ontology-based model has some weak points such as ontology data size, processing time, and limitation of network bandwidth. However, these problems can be resolved by customizing properly to fit the mission and characteristics of the unit. Moreover, development of the next-generation communication infrastructure can expedite the intelligent surveillance and reconnaissance service and may be expected to contribute greatly to expanding the information capacity.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.05a
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• pp.1381-1384
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• 2005

빠른 속도로 확산되고 있는 모바일 기기는 카메라, GPS, RFID 등과 같은 다양한 센서를 장착하고 Wi-Fi, WiMAX, WiBro 등의 무선 네트워크를 지원하는 형태로 발전하고 있다. 이러한 발전으로 사용자는 언제 어디서나 주변의 컴퓨팅 자원을 이용할 수 있게 되었고 모바일 기기의 서비스는 주변의 센서 또는 임베디드 컴퓨팅 장치로부터 수집되는 다양한 주변 환경 정보와 시스템 상태정보, 네트워크 상황정보 등의 디지털 정보를 이용하여 주변상황인식(context awareness)이 가능한 스마트 서비스로 발전하고 있다. 주변상황인식을 위하여 서비스는 주변에 존재하는 다양한 장치를 효율적으로 검색하고 이질적인(Heterogeneous) 장치와 정보의 표현 및 전송에 대한 호환성이 필요하다. 이러한 문제는 규격화된 프레임워크의 사용으로 해결할 수 있으며 상황정보의 관리 기능을 추가하여 서비스 개발의 생산성을 높일 수 있다 본 논문에서는 모바일 컴퓨팅 환경에서 상황정보의 제공과 사용에 적합한 프레임워크로서 MoCE(Mobile Context Exploerer) 아키텍처를 설계하였다. MoCE 는 상황정보의 수집, 변환, 분류, 통합 등의 기능을 제공하고 모바일 환경의 특성에 기인한 상황정보 발견 및 전송 프로토콜을 설계하여 사용하고 있다. 또한 Surround multiCam 서비스 예제를 구현하여 제안한 아키텍처의 안정성 및 성능을 실험하였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.12
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• pp.3675-3681
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• 2009

One of the most important factors in the lifetime of WSN(Wireless Sensor Network) is the limited resources and static control problem of the sensor nodes. In order to achieve energy efficiency and network utilities, sensor nodes can be well organized into one cluster and selected head node and normal node by dynamic conditions. Various clustering algorithms have been proposed as an efficient way to organize method based on LEACH algorithm. In this paper, we propose an efficient clustering algorithm using information entropy theory based on LEACH algorithm, which is able to recognize environmental differences according to changes from data of sensor nodes. To measure and analyze the changes of clusters, we simply compute the entropy of sensor data and applied it to probability based clustering algorithm. In experiments, we simulate the proposed method and LEACH algorithm. We have shown that our data balanced and energy efficient scheme, has high energy efficiency and network lifetime in two conditions.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.509-512
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• 2008

Ubiquitous Computing System란, 언제 어디서나 통신 및 컴퓨팅이 가능하고 컴퓨팅 시스템이 상호간에 정보를 공유하고 협력하는 컴퓨팅 시스템이다. 이로써 기존의 컴퓨팅 환경과 같이 사용자와 컴퓨터간의 대화형 상호작용이 아닌 물리적인 환경 상황(Context)등을 시스템이 스스로 인식하고 이를 기반으로 사용자와의 상호 작용을 지원하는 상황인식 기술이 필수적인 요소로 부각되고 있다. 또한, Ubiquitous Computing System을 위해 사용자 및 주변 환경 정보를 감지하는 센서(Sensor) 기술이 필요하다. 하지만 사용자 및 주변 환경으로부터 입력되는 불확실하거나 모호한 상황정보에 대한 표현과 추론에 대한 연구는 부족한 실정이다. 본 논문은 이런 이유에서 Rule-based System을 기반으로 CRS와 DOS의 개념을 도입한 새로운 상황인식 기반의 Architecture를 제안하고, 이를 VHDL을 통해 SoC로 구현하였다. CRS를 통해 실시간으로 다양한 센서에서 들어오는 많은 데이터에 가중치를 부여하여 각 센서마다 중요도를 달리 부여한다. 이로써, System은 Sensor 입력 값의 중요도에 따라 처리 순서를 우선적으로 부여하여 처리 속도를 높인다. 또, DOS를 통해 각양각색의 사용자에게 획일적인 서비스를 제공하는 것이 아니라 상황 변화의 패턴에 따라 개별화되고 특화된 서비스를 제공한다. 마지막으로, Ubiquitous Computing System의 향후 발전 가능성을 예상하고, 본 논문에서 제시한 Context-aware Architecture에 의해 구현된 UoC의 유용성을 짐작해 본다.

• Journal of Digital Convergence
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• v.15 no.5
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• pp.217-223
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• 2017

With the development of sensor networks and Internet of Things (IoT) technology, personalized context information has been collected and customized services can be provided to related users. Currently, the context information system is at the level of analyzing and recognizing user specific behavioral characteristics and generating events.In the IoT environment, IoT products themselves should provide the required services with minimal user intervention, rather than acting for a specific purpose. In this paper, to minimize the user intervention in the IoT environment, we implemented an automatic attendance recognition system using context information from the ECG based on beacon. Environment of provided specific Context information, we compared and analyzed the degree of user intervention among the authentication method using ECG sensor in this paper and the existing authentication method. As a result of the analysis, we confirmed that the system implemented in this paper minimizes user intervention.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.10
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• pp.1248-1253
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• 2019

Using current evacuation methods, a crew describes the physical location of an accident and guides evacuation using alarms and emergency guide lights. However, in case of an accident on a large and complex building, an intelligent and effective emergency evacuation system is required to ensure the safety of evacuees. Therefore, several studies have been performed on intelligent path finding and emergency evacuation algorithms which are centralized guidance methods using gathered data from distributed sensor nodes. However, another important aspect is effective rescue guidance in an emergency situation. So far, there has been no consideration on the efficient rescue guidance scheme. Therefore, this paper proposes the genetic algorithm based emergency rescue guidance method using distributed wireless sensor networks. Performance evaluation using a computer simulation shows that the proposed scheme guarantees efficient path finding. The fitness converges to the minimum value in reasonable time. The density of each exit node is remarkably decreased as well.

• The Journal of the Korea Contents Association
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• v.10 no.12
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• pp.27-33
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• 2010

In this study, we conducted the classification experiments with GMM (Gaussian Mixture Model) from combining the extracted features by using microphone, Gyro sensor and Acceleration sensor in 9 different environment types. Existing studies of Context Aware wanted to recognize the Environment situation mainly using the Environment sound data with microphone, but there was limitation of reflecting recognition owing to structural characteristics of Environment sound which are composed of various noises combination. Hence we proposed the additional application methods which added Gyro sensor and Acceleration sensor data in order to reflect recognition agent's movement feature. According to the experimental results, the method combining Acceleration sensor data with the data of existing Environment sound feature improves the recognition performance by more than 5%, when compared with existing methods of getting only Environment sound feature data from the Microphone.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.1
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• pp.90-96
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• 2019

Storage cabinet in a lab in these days measures various environmental factors in real-time with IoT sensors. Preexisting system collects sensor data, analyze a risk and then command other equipment. Such centralized control system tends to have an issue with of speed slowing down. It's because when there are more storage cabinets, there are more data to process. In order to solve this issue, this report addresses decentralized IoT sensor based lab safety control system. It can analyze internal state of storage cabinet to identify any hazardous situations and effectively control them. Such decentralized control system using sensor modules for internal environment of the cabinet storage and automated control algorithm based on administrator's log history can manage any hazardous situations by automated control of environment factors of inside a lab. It would allow users to deal with a hazard if it happens. Even better, it can prevent it to happen from the beginning.

• Journal of Advanced Navigation Technology
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• v.26 no.5
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• pp.325-330
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• 2022

The sensors of aircraft are necessity for mission performance and fusion process of data from them is applied for increase of mission efficiency and decrease of aircraft pilot workload. Data fusion is applied and developed to provide pilot a series of more processed data format about a specific target from sensors in aircraft. Military aircraft currently in operation are linked with a tactical data link such as Link-16 to display improved tactical situation to pilots to increase mission efficiency. By fusing the sensor data with improved accuracy obtained as the sensors' performance mounted on the aircraft become higher and the tactical situation information received through the tactical data link, it provides the pilot with a highly reliable tactical situation and mission environment, and expects efficient mission performance and high survivability. In this paper, a fusion architecture to produce fused data with realtime information from the sensors and data through a tactical data link is shown.