• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.47 no.8
• /
• pp.53-60
• /
• 2010

This paper proposes an efficient path maintaining scheme in the grid based wireless sensor networks. The proposed scheme provides the shortest path from a source node to a mobile sink node in a re-established dissemination path. The shortest path can save energy consumption to deliver data to the destination. The proposed scheme can also reduce the cost for path maintenance by reusing the existing path. The simulation results show that the proposed scheme reduces the path maintenance cost by 60% compared to the conventional schemes.

• Journal of the Korea Society of Computer and Information
• /
• v.19 no.11
• /
• pp.81-90
• /
• 2014

For necessary information sharing or operation control via wire-wireless/mobile network connecting of devices at disaster area in greatest need of attention, an emergency network efficient construction method quickly connecting nodes within specific range using Delaunay triangulation is proposed. The emergency network constructed by proposed method shows the same aggregate network length, but does more excellent performance in term of network construction time the more long max length connectable to adjacent node as compared with the network by naive method. In experiment of 1000 input terminal nodes, 5 max length connectable to adjacent node, our proposed method enhances 89.1% in execution time without network length increase compared to naive method. So our method can go well to many useful applications as shift construction of communication network of adjacent devices, internet of things and efficient routing in the sensor network in continuous improvement of communication capability.

• Journal of the Korea Society for Simulation
• /
• v.25 no.3
• /
• pp.1-14
• /
• 2016

This paper proposes four general wireless gateway types, which are distinguished by their own processing ways to connect between a wireless sub-network of things and the mobile internet that links mobile network to internet step by step. In this paper, we also design general processing procedures of these four types using the state transition model. Gateways of each types were developed on the basis of the resulted state transition models and their performances were evaluated through several tests, analyzed, and compared each other. As the results of our evaluation, compared with the other types, the type, which combines both of a low-power Sleep-interrupt way and polling ways for receiving data or responses in all the waiting states of a gateway, shows the best performance in all of data transmission real-timeliness, data loss and energy consumption.

• Journal of Digital Convergence
• /
• v.12 no.1
• /
• pp.319-324
• /
• 2014

In recent years, high-performance flying drones attract attention for many peoples. In particular, the drone equipped with multi-rotor is expanding its range of utilization in video imaging, aerial rescue, logistics, monitoring, measurement, military field, etc. However, the control function of its controller is very simple. In this study, using a G-sensor mounted on a mobile device, implements an enhanced controller to control flying drones through the intuitive gesture of user. The implemented controller improves the gesture recognition performance using a neural network algorithm.

• Journal of the Institute of Electronics Engineers of Korea CI
• /
• v.46 no.3
• /
• pp.116-122
• /
• 2009

Mobile Wireless Sensor Network is an organized collection of sensor nodes and mobile sink nodes, in which the sensor node transmits the signal to the sink node. In real environment, there are many cases in which sinks have mobility caused by the people, the vehicle and etc. Since all nodes in the sensor networks have limited energy, many researches have been done in order to prolong the lifetime of the entire network. In this paper we propose Dynamic Local Update-based Routing Protocol(D-LURP) that prolong the lifetime of the entire network to efficiently maintain frequent location update of mobile sink static sensor nodes in Mobile WSNs. When the sink node moves out of the local broadcasting area the proposed D-LURP configures dynamically the local update area consisted of the new local broadcasting area and the previous dissemination node(DN) and find the path between the DN and the sink node, instead of processing a new discovering path like LURP. In this way the processing of broadcasting sink node's location information in the entire network will be omitted. and thus less energy will be consumpted. We compare the performances of the proposed scheme and existing Protocols.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2018.05a
• /
• pp.347-350
• /
• 2018

In order for an IoT system to automatically make the house temperature pleasant for the user, the system needs to predict the optimal start-up time of air-conditioner or heater to get to the temperature that the user has set. Predicting the optimal start-up time is important because it prevents extra fee from the unnecessary operation of the air-conditioner and heater. This paper introduces an ANN(Artificial Neural Network) and an IoT system that predicts the cooling and heating time in households using air-conditioner and heater. Many variables such as house structure, house size, and external weather condition affect the cooling and heating. Out of the many variables, measurable variables such as house temperature, house humidity, outdoor temperature, outdoor humidity, wind speed, wind direction, and wind chill was used to create training data for constructing the model. After constructing the ANN model, an IoT system that uses the model was developed. The IoT system comprises of a main system powered by Raspberry Pi 3 and a mobile application powered by Android. The mobile's GPS sensor and an developed feature used to predict user's return.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.45 no.5
• /
• pp.1-11
• /
• 2008

Wireless Sensor Networks is applied to improvement of life convenience or service like U-City as well as environment pollution, tunnel and structural health monitoring, storm, and earthquake diagnostic system. To increase the usability of sensor data and applicability, mobile devices and their facilities allow the applications of sensor networks to give mobile users and actuators the results of event detection at anytime and anywhere. In this paper, we present MUSNEMO(Multi-sensor centric Ubiquitous Smart sensor NEtwork using Mobile devices) developed system for providing more efficient and valuable information services with a variety of mobile devices and network camera integrated to WSN. Our system is performed based on IEEE 802.15.4 protocol stack. To validate system usability, we built sensor network environments where were equipped with five application sensors such magnetic, photodiode, microphone, motion and vibration. We also built and tested proposed MUSNEMO to provide a novel model for event detection systems with mobile framework.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.43 no.1 s.307
• /
• pp.67-74
• /
• 2006

Contort-aware computing technology is one of the key technology of ubiquitous computing in the mobile device environment. Context recognition computing enables computer applications that automatically respond to user's everyday activity to be realized. In this paper, We use accelerometer could sense activity states of the object and apply to mobile devices. This method for estimating human motion states utilizes various statistics of accelerometer data, such as mean, standard variation, and skewness, as features for classification, and is expected to be more effective than other existing methods that rely on only a few simple statistics. Classification algorithm uses simple decision tree instead of existing neural network by considering mobile devices with limited resources. A series of experiments for testing the effectiveness of the our context detection system for mobile applications and ubiquitous computing has been performed, and its result is presented.

• Journal of Digital Contents Society
• /
• v.6 no.2
• /
• pp.131-135
• /
• 2005

Nowadays, the demand for the wireless technology has gradually increased to support the services of high speed wired internet and also the interest of a mobile terminal convergence has increased. In the next generation, the mobile terminal could merge with the celluar phone, wireless LAN, portable internet, digital multimedia brodcasting, mobile game and sensor(smart-tag and biometrics) through the unified single user interface. Moreover, the system is supported to multi-mode at difference networks, which have variable functions and high performance for available service. Inthis paper, we investigate the minimum requirements and the core technologies of the next generation mobile terminals.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.14 no.4
• /
• pp.51-56
• /
• 2014

Thesedays, there are many smart device applications developed, especially on the using various sensors included in the smart device. Smart devices have several sensors which are camera, GPS, mike, and communication module for collecting ubiquitous environment, and many applications are developed by using such sensors. In this paper, we developed the multimedia stream architecture and examined the smart device applications based on open source with front and back-end server clouds for developing the conceptual architecture. Also, we examined the back-end distributed servers, realtime multimedia stream transferring, multi-media store, and media relay for other server and smart devices. We test the examined architecture on the real target environment to collect the SIP initial setup time, media stream delay, and end-to-end play time. The test results show that there have good network operation environment to provide realtime multimedia services, and we need to improve the end-to-end play time by minimizing the initial setup time.