• The KIPS Transactions:PartD
• /
• v.15D no.5
• /
• pp.599-608
• /
• 2008

Advanced wireless network and sensor technologies are capable of collecting information such as temperature, humidity, weight, and location about objects at real time in logistics area. Besides, users want to be notified of contextual information about interest of objects whenever they want it and wherever they want it. To satisfy these requirements, applications should collect and analyze contextual information at real time, and must support a service that can notify it to wanted users. Event-based service is one of the way to satisfy these requirement of users. In this paper, we design an event notification system focused on location- and RFID-based logistics area. To do this, we present XML-based event expression model, ECA-based profile definition model, and an algorithm that has high scalability by distinguishing event filtering in two steps. Based on these designs, our implemented system can apply to not only logistics area but also intelligent traffic control system based on RFID or GPS devices.

• Nuclear Engineering and Technology
• /
• v.55 no.4
• /
• pp.1571-1584
• /
• 2023

In this study, a numerical analysis was performed as part of an international joint research project to reproduce a real cable tray fire that occurred in the heater bay area of the turbine building of a nuclear power plant. A sensitivity analysis was performed on various input parameters to derive results consistent with the sprinkler activation time obtained from the fire event analysis. For all sensitive parameters, the normalized sprinkler activation time correlated well with the power function of the normalized sprinkler height. A correlation equation was developed to identify the sprinkler activation time at any location when determining the slope or fire growth rate under the conditions assuming a linear or t-squared heat release rate (HRR) time curve. Various cable fire growth assumptions were used to determine which assumption was better to provide the prediction coincident with the information given from the fire event analysis in terms of the sprinkler activation time and total energy generated from cables damaged by fire. In the comprehensive analysis of all the sensitive parameters, the standard deviation of the input parameters increased as the sprinkler height decreased. Within the range of the sensitivity parameter values given in this study, when considering all sprinkler heights, the standard deviation of the cable model change was the largest and that of the overhang position change was the smallest.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.38A no.8
• /
• pp.688-696
• /
• 2013

In wireless sensor networks, real-time applications have to ensure the timely delivery of real-time data. Recently, OMLRP (On-demand Multi-hop Look-ahead Routing Protocol) has been proposed to improve the timeliness of wireless sensor networks. The protocol needs initialization time to establish multi-hop information based routing path because it performs incremental look-ahead of the information. Consequently, the protocol deteriorates DDSR (Deadline Delivery Success Ratio) as an event moves because it takes little consideration of event mobility. In this paper, we proposed a Real-time Routing for Events Mobility (RREM) which exploits a data redirection in order to improve the DDSR of moving events. Instead of recollecting muti-hop look-ahead information, the RREM redirects the data to a sensor node holding the information collected in a previous round. We verify the timeliness and energy efficiency of RREM using various MatLab simulations.

• Proceedings of the KSRS Conference
• /
• 2007.10a
• /
• pp.568-572
• /
• 2007

With the proliferation of advanced wireless network and sensor technologies, smart devices under USN(ubiquitous sensor network) environment are capable of collecting context information such as temperature, humidity, weight, and location about objects at real time. Therefore, applications must be able to analyze collected information and notify useful information to wanted users timely. This service can be realized by implementing an event-based middleware. In the middleware, event messages collected from physical environment will be filtered according to profiles that users define in advance and the result will be sent to the interested users. In this paper, we present XML-based event model, ECA-based profile model, and the architecture of an event-based middleware suitable to USN environment. We will also model and describe them using the examples of logistics area. By implementing the system based on the design above, the middleware enable applications or users to easily access to physical sources. The proposed middleware can also apply to not only logistics area but also other various areas under USN environment such as intelligent traffic control system, national disaster management system and u-medical system.

• The Bulletin of The Korean Astronomical Society
• /
• v.40 no.1
• /
• pp.83.4-84
• /
• 2015

We report that a strong downflow event caused three-minute oscillations in the solar atmosphere. Our observations were carried out by using the Fast Imaging Solar Spectrograph (FISS) of the 1.6 meter New Solar Telescope (NST) and the Interface Region Imaging Spectrograph (IRIS). Our main findings are as follows: (1) The strong downflow was seen at the $H{\alpha}$ absorption line at first, and then appeared at the Si IV and C II emission lines. It seems that the characteristics of the downflow are consistent with a coronal rain event. (2) After the event, oscillations of velocity were identified in the chromospheric lines and transition region lines. (3) The amplitudes of oscillations were 2km/s at Mg II line and 3km/s at C II and Si IV lines and decreased with time. (4) The period of the oscillation was 2.67 minutes at first, but gradually increased with time. Our findings are in agreement with Chae & Goode (2015)'s theory that of acoustic waves generated by a disturbance in a gravitationally-stratified medium.

• Journal of Communications and Networks
• /
• v.14 no.6
• /
• pp.597-605
• /
• 2012

With the smart grid coming near, wide-area supervisory control and data acquisition (SCADA) becomes more and more important. However, traditional SCADA systems are not suitable for the openness and distribution requirements of smart grid. Distributed SCADA services should be openly composable and secure. Event-driven methodology makes service collaborations more real-time and flexible because of the space, time and control decoupling of event producer and consumer, which gives us an appropriate foundation. Our SCADA services are constructed and integrated based on distributed events in this paper. Unfortunately, an event-driven SCADA service does not know who consumes its events, and consumers do not know who produces the events either. In this environment, a SCADA service cannot directly control access because of anonymous and multicast interactions. In this paper, a distributed security framework is proposed to protect not only service operations but also data contents in smart grid environments. Finally, a security implementation scheme is given for SCADA services.

• 제어로봇시스템학회:학술대회논문집
• /
• 2000.10a
• /
• pp.364-364
• /
• 2000

Timed Petri Net(TPN) is one of methods to model and to analyze Discrete Event Dynamic Systems(DEDSs) with real time values. It has two time values, earliest firing time ($\alpha$$_{i}$) and latest firing time ($\beta$$_{I}$) for the each transition. A transition of TPN is fired at arbitrary time of time interval ($\alpha$$_{I}$, $\beta$$_{i}$). Uncertainty of firing time gives difficulty to analyze and estimate a modeled system. In this paper, we proposed the Fuzzy Transition Timed Petri Net(FTTPN) with fuzzy theory to determine the optimal transition time (${\gamma}$$_{i}$). The transition firing time (${\gamma}$$_{i}$) of FTTPN is determined from fuzzy controller which is modeled with information of state transition. Each of the traffic signal controllers are modeled using the proposed method and timed petri net. And its Performance is evaluated by simulation of traffic signal controller. controller.

• Journal of Institute of Control, Robotics and Systems
• /
• v.13 no.6
• /
• pp.596-602
• /
• 2007

Recently, many ECUs(Electronic Control Units) have been used to enhance the vehicle safety, which leads to a distributed real-time control system. The distributed real-time control system requires to reduce the network delay for dependable real-time performance. There are two different paradigms by which a network protocol operates: event-triggered and time-triggered. This paper focuses on implementation of a time-triggered protocol. i.e. TTP/C(Time-Triggered Protocol/class C). This paper presents a design method of TTP control network and performance evaluation of distributed real-time control system using TTP protocol.

• The Journal of the Acoustical Society of Korea
• /
• v.28 no.7
• /
• pp.674-679
• /
• 2009

This paper proposes a method of player event retrieval using combination of two functions: detection of player name in speech information and detection of sound event from audio information in golf videos. The system consists of indexing module and retrieval module. At the indexing time audio segmentation and noise reduction are applied to audio stream demultiplexed from the golf videos. The noise-reduced speech is then fed into speech recognizer, which outputs spoken descriptors. The player name and sound event are indexed by the spoken descriptors. At search time, text query is converted into phoneme sequences. The lists of each query term are retrieved through a description matcher to identify full and partial phrase hits. For the retrieval of the player name, this paper compares the results of word-based, phoneme-based, and hybrid approach.

• Journal of Institute of Control, Robotics and Systems
• /
• v.6 no.6
• /
• pp.478-485
• /
• 2000

A discrete event systems (DES) is a physical system that is discrete in time and state space, asynchronous (event rather than clock-driven), and in some sense generative(or nondeterministic). This paper presents the design of fifteen modular supervisors to control an experimental CIM testbed. These supervisors are nonblocking, controllable and nonconflicting. After verification of the supervisors by simulation, the supervisors for AGV system have been implemented to demonstrate their efficacy.