• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.8
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• pp.1820-1831
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• 2011

When both types of periodic and aperiodic tasks are required to run on a sensor node platform with limited energy resources, we propose an energy-efficient hybrid task scheduling technique that guarantees the deadlines of real-time tasks and provides non-real-time tasks with good average response time. The proposed hybrid task scheduling technique achieved better performance than existing EDF-based DVS scheduling techniques available in the literature, the FIFO-based TinyOS scheduling technique, and the task-clustering based non-preemptive real-time scheduling technique.

• International conference on construction engineering and project management
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• 2005.10a
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• pp.539-543
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• 2005

The research presented in this paper enables real-time 3D modeling to help make construction processes ultimately faster, more predictable and safer. Initial research efforts used an emerging sensor technology and proved its usefulness in the acquisition of range information for the detection and efficient representation of static and moving objects. Based on the time-of-flight principle, the sensor acquires range and intensity information of each image pixel within the entire sensor's field-of-view in real-time with frequencies of up to 30 Hz. However, real-time working range data processing algorithms need to be developed to rapidly process range information into meaningful 3D computer models. This research ultimately focuses on the application of safer heavy equipment operation. The paper compares (a) a previous research effort in convex hull modeling using sparse range point clouds from a single laser beam range finder, to (b) high-frame rate update Flash LADAR (Laser Detection and Ranging) scanning for complete scene modeling. The presented research will demonstrate if the FlashLADAR technology can play an important role in real-time modeling of infrastructure assets in the near future.

• Journal of the Korea Society of Computer and Information
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• v.24 no.4
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• pp.57-63
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• 2019

In this paper, we propose a new framework to control VR(Virtual reality) contents in real time using user's mouth-wind and acceleration sensor of mobile device. In VR, user interaction technology is important, but various user interface methods is still lacking. Most of the interaction technologies are hand touch screen touch or motion recognition. We propose a new interface technology that can interact with VR contents in real time using user's mouth-wind method with acceleration sensor. The direction of the mouth-wind is determined using the angle and position between the user and the mobile device, and the control position is adjusted using the acceleration sensor of the mobile device. Noise included in the size of the mouth wind is refined using a simple average filter. In order to demonstrate the superiority of the proposed technology, we show the result of interacting with contents in game and simulation in real time by applying control position and mouth-wind external force to the game.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.585-588
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• 2009

Wireless Sensor Network (WSN) is consisted of lots of tiny sensor nodes with limited processing power and computing resources. Thus, the most critical and fundamental element of WSN technology is sensor node, which gathers environmental information and transmits it to the user application systems. Due to the technological advancement, sensor nodes are become smaller and more intelligent, hence, expand their application area. Specifically, implantable wireless sensor node technology, to monitor and treat disease by implanting tiny sensor nodes into human body or livestock, shows further directions of WSN. In this paper, we have designed an implantable wireless sensor node to monitor livestock body temperature in real time. We also discussed on the additional considerations to implement real time bio-monitoring systems.

• Journal of Communications and Networks
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• v.15 no.1
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• pp.87-101
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• 2013

In industrial applications, sensor networks have to satisfy specified time requirements of exchanged messages. IEEE 802.15.4 defines the communication protocol of the physical and medium access control layers for wireless sensor networks, which support real-time transmission through guaranteed time slots (GTSs). In order to improve the performance of IEEE 802.15.4 in industrial applications, this paper proposes a new traffic scheduling algorithm for GTS. This algorithm concentrates on time-critical industrial periodic messages and determines the values of network and node parameters for GTS. It guarantees real-time requirements of periodic messages for industrial automation systems up to the order of tens to hundreds of milliseconds depending on the traffic condition of the network system. A series of simulation results are obtained to examine the validity of the scheduling algorithm proposed in this study. The simulation results show that this scheduling algorithm not only guarantees real-time requirements for periodic message but also improves the scalability, bandwidth utilization, and energy efficiency of the network with a slight modification of the existing IEEE 802.15.4 protocol.

• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.823-825
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• 2003

A sensor system was designed to measure real time vibro displacement of civil structure. The He-Ne laser is used for the displacement measuring method, because it guarantees short time stabilization, long time output power stability. Also, it guarantees simple maintenances and repairs under actual using condition. The line CCD image sensor(Tcd-142d) is used to detect the displacement of Ne-Ne laser responding to the vibro of civil structure. For accurate measurement and comparison, CDP-50 is used. Usually CDF-50 (Strain type displacement device) is used for the standard correction device of optical measurement equipments. The data processing part is consists of Optical sensor part, Wireless data transmission device, DAQp-1200, and LapView program. The displacement data of vibro from optical sensor part inputted to wireless data transmission device and then transmitted to DAQp-1200 in main control room. DAQp-1200 performs A/D conversion for the receiving data. After that the converted data inputted to computer system using LapView program for user display. The significance of this paper is to develope a convenient, accurate and lost saving real time displacement measurement system for the civil structure.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.36 no.3
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• pp.177-184
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• 2018

In case that limited resources can be mobilized, non-structural countermeasures such as 'monitoring using Information and Communication Technology might be one of solutions to mitigate disaster risks. Having established the monitoring system, operational and maintenance costs to maximize the effectiveness might trouble the authority concerned or duty attendant who is in charge. In this respect, "Guerrilla Sensor" would be very cost effective because of the inherent mobility characteristic. The sensor device with the IRIS camera and GPS (Global Positioning System) equipped, is basically battery-operated and communicates with WCDMA (Wideband Code Division Multiple Access). It has a strong advantage of capabilities for 'Disaster Response' with immediate and prompt action on the spot, making the best use of IoT (Internet of Things), especially with the mobile web. This paper will explain how the sensor system works in real-time GIS (Geographic Information System) pinpointing the exact location of the abnormal movement/ground displacement and notifying the registered users via SMS (Short Message Service). Real time monitoring with early warning and evaluation of current situations with LBS (Location Based Service), live image and data information can help to reduce the disaster impact. Installation of Guerrilla sensor for a real site application at Gimcheon, South Korea is also reported.

• Journal of information and communication convergence engineering
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• v.10 no.3
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• pp.231-236
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• 2012

For real-time wireless sensor network applications, it is essential to provide different levels of quality of service (QoS) such as reliability, low latency, and fault-tolerant traffic control. To meet these requirements, an (m,k)-firm based real-time routing protocol has been proposed in our prior work, including a novel local transmission status indicator called local DBP (L_DBP). In this paper, a fault recovery scheme for (m,k)-firm real-time streams is proposed to improve the performance of our prior work, by contributing a delay-aware forwarding candidates selection algorithm for providing restricted redundancy of packets on multipath with bounded delay in case of transmission failure. Each node can utilize the evaluated stream DBP (G_DBP) and L_DBP values as well as the deadline information of packets to dynamically define the forwarding candidate set. Simulation results show that for real-time service, it is possible to achieve both reliability and timeliness in the fault recovery process, which consequently avoids dynamic failure and guarantees meeting the end-to-end QoS requirement.

• Journal of information and communication convergence engineering
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• v.14 no.2
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• pp.84-88
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• 2016

As good example of potential application-specific requirement, (m,k)-firm real-time streams have been recently introduced to deliver multimedia data efficiently in wireless sensor networks. In addition to stream model, communication protocols to meet specific (m,k)-firm real-time streams have been newly developed or extended from existing protocols. However, since the existing schemes for an (m,k)-firm stream have been proposed under typical flat architecture, the scalability problem remains unsolved when the number of real-time flows increases in the networks. To solve this problem, in this paper, we propose a new clustering scheme for an (m,k)-firm stream. The two different clustering algorithms are performed according to either the (m,k)-firm requirement or the deadline. Simulation results are presented to demonstrate the suitability of the proposed scheme under hierarchical architecture by showing that its performance is acceptable irrespective of the increase in the number of flows.

• Journal of the Korean Society of Industry Convergence
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• v.7 no.2
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• pp.167-172
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• 2004

Neural networks are used in the framework of sensor based tracking control of robot manipulators. They learn by practice movements the relationship between PSD(an analog Position Sensitive Detector) sensor readings for target positions and the joint commands to reach them. Using this configuration, the system can track or follow a moving or stationary object in real time. Furthermore, an efficient neural network architecture has been developed for real time learning. This network uses multiple sets of simple back propagation networks one of which is selected according to which division (Corresponding to a cluster of the self-organizing feature map) in data space the current input data belongs to. This lends itself to a very training and processing implementation required for real time control.