• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.4
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• pp.1191-1201
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• 2014

The rip current warning index function, which estimates the likelihood of dangerous rip current in the real-time rip current warning system operating to help mitigate against rip current accidents at Haeundae beach, was studied. The rip current warning index evaluated as a function of various real-time observations was developed based on Choi et al. (2013b). This study shows a version of rip current warning index improved by including the effect of wave direction and spreadings of frequency-directional spectrum on rip current likelihood. The wave and tidal observations in 2012 at Haeundae coast were applied to the rip current index function, and its performances at several real events found based on CCTV images were presented and analyzed.

• Journal of Korea Multimedia Society
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• v.16 no.4
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• pp.493-501
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• 2013

A key challenge in massively multiplayer on-line game(MMOG) systems is providing real-time response latencies to the large number of concurrent game players. MMOG systems are a kind of soft real-time systems because requests from many players should be responded within specified time constraints. Client events have different timeliness and consistency requirements according to their nature in the game world. These requirements lead to tasks with different priorities on CPU processing. In order to meet their timing constraints, we propose priority scheduling methods that attempt to allocate preferentially more CPU bandwidth to serve an task with the higher priority level in the presence of transient overloading. The proposed scheduling methods are capable of enhancing real-time performance of MMOG system by maximizing the number of tasks with higher priority completed successfully within their deadlines while minimizing total average latency of tasks finished after given deadlines. The performance of these scheduling methods is evaluated through extensive simulation experiments.

• Journal of KIISE
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• v.44 no.1
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• pp.84-94
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• 2017

Recently, the importance of velocity, one of the characteristics of big data (5V: Volume, Variety, Velocity, Veracity, and Value), has been emphasized in the data processing, which has led to several studies on the real-time stream processing, a technology for quick and accurate processing and analyses of big data. In this paper, we propose a Squall framework using Time-triggered Message-triggered Object (TMO) technology, a model that is widely used for processing real-time big data. Moreover, we provide a description of Squall framework and its operations under a single node. TMO is an object model that supports the non-regular real-time processing method for certain conditions as well as regular periodic processing for certain amount of time. A Squall framework can support the real-time event stream of big data and micro-batch processing with outstanding performances, as compared to Apache storm and Spark Streaming. However, additional development for processing real-time stream under multiple nodes that is common under most frameworks is needed. In conclusion, the advantages of a TMO model can overcome the drawbacks of Apache storm or Spark Streaming in the processing of real-time big data. The TMO model has potential as a useful model in real-time big data processing.

• The KIPS Transactions:PartA
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• v.9A no.2
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• pp.181-190
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• 2002

IEEE1394 is a de facto standard for the home network interfaces of digital multimedia home devices including digital A/V systems, digital camcorders, and PCs. Recently, it has been used in applications to guarantee the real-time characteristics such as home automation system and IICP (Instrument and Industrial Control Protocol). In order to guarantee real-time requirements in these IEEE1394-based real-time applications, this thesis proposes the software architecture of an IEEE1394 based home network that supports the guarantee for service's react-time characteristics. The proposed architecture has a real-time IEEE1394 device driver and event service architecture for guarantee real-time characteristics. The real-time device driver supports priority-based queueing of packets and mechanism to reduce the interrupt latency time in ISR. The event service architecture supports a real-time events delivery based on home network service using real-time event channel. This architecture can accommodate the real-time requirements of various applications and services such as digital multimedia services with QoS guarantees. home automation system required real-tine characteristics.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.5
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• pp.1235-1242
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• 2015

In global shipping logistics, it is important for users to keep track of the location of their continuously moving cargos. Analyzing the GPS data stream coming from the tag which is attached to the cargo, we are able to keep track of the cargo location in terms of going into or out of a certain logistics area using the information of the spatial relationship change between the tag and the logistics area. In this paper, we propose a simulation system for measuring the precision and false alarm rate of the cargo location tracking algorithm which generates spatial events over the global logistics areas. Due to the difficulty of experiment with a real tag, we developed a tag emulator to create a virtual tag which operates exactly like a real tag. We show the cargo location tracking system works correctly with the tag emulator which communicates with it using the same protocol as the real tag.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.53 no.12
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• pp.637-644
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• 2004

This paper proposes an expert system with the knowledge learning capability which can enhance the safety and effectiveness of substation operation in the automated substation as well as existing substation by inferring multiple events such as main transformer fault, busbar fault and main transformer work schedule under multiple inference mode and multiple objective mode and by considering totally the switch status and the main transformer operating constraints. Especially inference mode includes the local minimum tree search method and pattern recognition method to enhance the performance of real-time bus reconfiguration strategy. The inference engine of the expert system consists of intuitive inferencing part and logical inferencing part. The intuitive inferencing part offers the control strategy corresponding to the event which is most similar to the real event by searching based on a minimum distance classification method of pattern recognition methods. On the other hand, logical inferencing part makes real-time control strategy using real-time mode(best-first search method) when the intuitive inferencing is failed. Also, it builds up a knowledge base or appends a new knowledge to the knowledge base using pattern learning function. The expert system has main transformer fault, main transformer maintenance work and bus fault processing function. It is implemented as computer language, Visual C++ which has a dynamic programming function for implementing of inference engine and a MFC function for implementing of MMI. Finally, it's accuracy and effectiveness is proved by several event simulation works for a typical substation.

• Journal of Korean Society of Transportation
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• v.25 no.5
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• pp.173-182
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• 2007

An innovative feature of this study is to propose a methodology for evaluating safety performance in real time based on vehicle trajectory data extracted from video images. The essence of evaluating safety performance is to capture unsafe car-following events between individual vehicles traveling surveillance area. The proposed methodology applied two indices including real-time safety index (RSI) based on the concept of safe stopping distance and time-to-collision (TTC) to the evaluation of safety performance. It is believed that outcomes would be greatly utilized in developing a new generation of video images processing (VIP) based traffic detection systems capable of producing safety performance measurements. Relevant technical challenges for such detection systems are also discussed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.9
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• pp.2056-2063
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• 2012

In a port terminal, containers are stored and transshipped by yard tractors and crane vehicles. For operation efficiency of the terminal, location information of these vehicles is an essential factor. However, most of port terminals try to estimate location of these assets using indirect methods such as event tracking of shipping or unshipping containers. Because these kinds of events are rarely occurred, location of the event includes seriously locating error compared to a real location of vehicle. In this paper, we propose a real-time asset tracking system to obtain accurate and reliable location of terminal assets. The proposed system overcomes a location estimation error caused by container stacks which interrupt wireless communication. In order to mitigate uncertainty and increase accuracy of location estimation, we designed hardwares and multi-step locating system to resolve additional preblems. We implemented system components, and installed these at a port environment for evaluation. The result shows superiority of the system that the accuracy is approximately 5.87 meters (CEP).

• The KIPS Transactions:PartA
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• v.13A no.6 s.103
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• pp.481-488
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• 2006

FRP(Functional Reactive Programming) is a kind of embedded language in Haskell, it declaratively program reactive system based on two essential high-order types named behavior and events. This Paper design and implementation RT-FRP(Real-time Functional Reactive Programming) translator for using FRP in embedded systems with many constraints. The RT-FRP translator generates a C Program from an RT-FRP program according to the operational semantics of the RT-FRP language. To show the effectiveness of the RT-FRP translator, we loaded and executed the test program generated by the translator onto a real embedded system, LEGO Mindstorm. According to the experimental result, the reactive system software can be programmed more concisely using RT-FRP than using an imperative counter part although the size of the binary code is rather increased.

• Journal of Korea Water Resources Association
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• v.42 no.3
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• pp.259-270
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• 2009

The applicability of the developed distributed rainfall runoff model using a multi-directional flow allocation algorithm and a real-time updating algorithm was evaluated. The rainfall runoff processes were simulated for the events of the Andong dam basin and the Namgang dam basin using raingauge network data and weather radar rainfall data, respectively. Model parameters of the basins were estimated using previous storm event then those parameters were applied to a current storm event. The physical propriety of the multi-directional flow allocation algorithm for flow routing was validated by presenting the result of flow grouping for the Andong dam basin. Results demonstrated that the developed model has efficiency of simulation time with maintaining accuracy by applying the multi-directional flow allocation algorithm and it can obtain more accurate results by applying the real-time updating algorithm. In this study, we demonstrated the applicability of a distributed rainfall runoff model for the advanced basin-wide flood management.