• Proceedings of the Korea Inteligent Information System Society Conference
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• 2001.06a
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• pp.377-381
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• 2001

An ATMS(Assumption-based Truth Maintenance System) has been widely used for maintaining the truth of information by detecting and solving contradictions in nile-based systems. But the ATMS can not correctly maintain the truth of the information in case that the generated information is satisfied within a time interval or includes data about temporal relations of events in time varying situations, because it has no mechanism manipulating temporal data. In this paper, The extended ATMS method is proposed, which can maintain the truth of the information in the inference system using information changing over time or temporal relations of events. In order to maintain contexts generated by relations of events, the label representation method is modified, the disjunction, conjunction simplification method in the label-propagation procedure and nogood handling method of the conventional ATMS are modified, too.

• Journal of Intelligence and Information Systems
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• v.15 no.3
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• pp.137-150
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• 2009

This paper proposes the hybrid heuristic method to apply the opportunity time to solve the vehicle routing and scheduling problem with time constraints(VRSPTW). The opportunity time indicates the idle time which remains after the vehicle performs the unloading service required by each customer's node. In this proposed heuristic, we add the constraints to VRSPTW model for the opportunity time. We also obtain the initial solution by applying the cost evaluation function to the insertion strategy considering the opportunity time. In addition, we improve the former result by applying the opportunity time to the tabu search strategy by swapping the customer's node. Finally, we suggest the construction strategies of initial routing which can efficiently acquire the nearest optimal solution from various types of data in terms of geographical condition, scheduling horizon and vehicle capacity. Our experiment show that our heuristic can get the nearest optimal solution more efficiently than the Solomon's I1 heuristic.

• The Transactions of the Korea Information Processing Society
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• v.7 no.5S
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• pp.1666-1675
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• 2000

This paper proposes a RTWM (Real-Time Web Middleware) framework for real-time EC(Electronic Commerce) systems. RTWM system is extended the existing COS( CORBA Object Service) model added to the event monitoring, real-time scheduler, real-time event filtering for supporting real-time concept of EC systems. Especially, this paper is concentrated on providing suitable event filtering function for EC system in order to meed various user time requirements under distributed system environment. It stores time constraint requirements an interesting event information input from users into QoS repository, then processes the data through appropriate RTFA(Real-Time Filtering Agent) module when real-time events occur. From this method, users can get the filtered event result reflected their requirements about real-time filtering. It means this system provides thigh QoS to users. In addition, it results in decreasing network traffic as unnecessary event information is filtered from network.

• Proceedings of the Korean Information Science Society Conference
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• 2008.06d
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• pp.291-296
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• 2008

Wireless network technologies are becoming more widely used in industrial environment. The industrial communication system requires a real-time delivery of messages. The sensors periodically senses the physical environment and wants to deliver the data in real-time to the sink. This paper proposes a real-time protocol for periodic messages on wireless sensor and actor networks to be used in industrial communications. The proposed protocol delivers the data message using the shortest path from the source and the nearest actor. The protocol considers the energy consumption by reducing the number of broadcast messages during flooding. We have evaluated the performance of the proposed protocol using QualNet simulator. The simulation results show that the data messages have been delivered in real-time and the number of broadcast messages is reduced from 90% to 35% compared the existing protocols.

• Journal of information and communication convergence engineering
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• v.18 no.3
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• pp.147-154
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• 2020

In this study, we created a system that can determine the number of vehicles entering and departing a charging station in real time for solving waiting time problems during refueling. Accordingly, we use the You Only Look Once object detection algorithm to detect and count the number of vehicles in the charging station and send the data to the Firebase Realtime Database. The result is shown using an Android application that provides a map function with the Kakao Maps API at the user interface side. Our system has an accuracy of 91% and an average response time of 3.1 s. Therefore, this system can be used by drivers to determine the availability of a charging station and to identify the charging station with the least waiting time for charging their vehicle.

• IEMEK Journal of Embedded Systems and Applications
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• v.2 no.2
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• pp.95-100
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• 2007

Recently ubiquitous application services are developed plentifully using RFID techniques in the field of distribution and security industries. However, except these field the applications using RFID are not mature yet. In this study, we proposed a real-time context service model of the u-conference based on the real-time contextual information acquired from conference and exposition. With collection of real-time contextual information for u-conference, the model can provide a lot of information services on the state of session attendee, doorway control, affairs, user certification, presentation progress etc. For the verification of proposed real-time context service model of u-conference, we design and implement the conference progress state service included the state of session attendee, user certification and presentation progress etc. This service provides the presentation state information included the current presenter, the paper list, the number of session attendee, the schedule and place of each session using the collecting RFID tag and the related information.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.522-523
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• 2017

Analog-to-Digital converter is designed using a current conveyor circuit and a time-to-digital converter. The analog voltage is sampled using the current conveyor circuit and then the voltage is converted to time information by the discharge of the sampling voltage. The time information is converted to digital value by the counter-type time-to-digital converter. In order to reduce the converted error the clock is synchronized with the time information pulse.

• The Journal of Information Systems
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• v.5
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• pp.411-427
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• 1996

As the application of real time expert systems has been expanded, the real time expert systems have become an integral part of the information society. Real time expert systems are viewed as a new paradigm to integrate real time problem solving and expert system technology. However, a substantial amount of work is still required to effectively handle a new and challenging opportunity for successful implementation of real time expert systems. In this article, the basic concepts and characteristics of real time expert systems are discussed. The article also presents, through the literature survey, the summary of real time expert systems applications and a class of tools, providing an enabling real time based expert system technology. Finally, the article discusses a set of requirements which real time expert systems must satisfy.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.207-210
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• 2009

The time information of sptio-temporal data in synchronization system of a mobile environment can be applied according to time data of various kinds. However, that previous data is synchronized related with progress of synchronization operation is a problem when saving the time data of sptio-temporal data depends on the registration time. In this paper, classifies the time used as time data for synchronization data, defines time data model suitable for synchronization of sptio-temporal data and suggests a synchronization system which uses time data model.

• Journal of Communications and Networks
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• v.7 no.4
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• pp.450-461
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• 2005

In this paper, we derive analytical expressions for the exact pairwise error probability (PEP) of a space-time coded system operating over spatially correlated fast (constant over the duration of a symbol) and slow (constant over the length of a code word) fad­ing channels using a moment-generating function-based approach. We discuss two analytical techniques that can be used to evaluate the exact-PEPs (and therefore, approximate the average bit error probability (BEP)) in closed form. These analytical expressions are more realistic than previously published PEP expressions as they fully account for antenna spacing, antenna geometries (uniform linear array, uniform grid array, uniform circular array, etc.) and scattering models (uniform, Gaussian, Laplacian, Von-mises, etc.). Inclusion of spatial information in these expressions provides valuable insights into the physical factors determining the performance of a space-time code. Using these new PEP expressions, we investigate the effect of antenna spacing, antenna geometries and azimuth power distribution parameters (angle of arrival/departure and angular spread) on the performance of a four-state QPSK space-time trellis code proposed by Tarokh et al. for two transmit antennas.