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

• Proceedings of the KIEE Conference
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• 1993.07a
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• pp.313-315
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• 1993

This paper presents the control of input/output automata. The input/output automata provides an appropriate model for discrete event systems consisting of concurrently-operating components. Ramadge and Wonham's supervisor controller can be transformed into the controllter of input/output automata. Using input/output automata, the modelling can be more realistic and concurrent discrete event systems can be controlled easily.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10b
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• pp.1240-1245
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• 1990

Intelligent Control is an extended paradigm that subsumes both control and AI paradigms, each of which is limited by its own abstractions. Autonomy, as a design goal, offers an arena where both control and AI paradigms must be applied -and a challenge to the viability of both as independent entities. We discuss hierarchical event-based control architectures in which AI and Control paradigms can be integrated within a model-based approach. In a niodel-based system, knowledge is encapsulated in the form of models at the various layers to support the predefined system objectives. Concepts are illustrated with a robotmanaged space-borne chemical laboratory.

• Proceedings of the KIEE Conference
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• 1997.07b
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• pp.590-592
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• 1997

A Discrete Event Dynamic System is a system whose states change in response to the occurrence of events from a predefined event set. A major difficulty in developing analytical results for the systems is the lack of appropriate modeling techniques. This paper proposes the use of Real-time Temporal Logic as a modeling tool for the analysis and control of DEDS. The Real-time Temporal Logic Frameworks is extended with a suitable structure of modeling hard real-time constraints. Modeling rules are developed for several specific situations. It is shown how the graphical model can be translated to a system of linear equations and constraints.

• Journal of Institute of Control, Robotics and Systems
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• v.9 no.11
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• pp.906-916
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• 2003

A multi-robot control algorithm using Petri-Net is proposed for 5vs5 robot soccer. The dynamic environment of robot soccer is modeled by defining the place and transition of each robot and converting it into Petri-Net diagram. Once all the places and transitions of robots are represented by the Petri-Net model, their actions can be chosen according to the roles of robots and position of the ball in soccer game, e.g., offensive, defensive and goalie robot. The proposed modeling method is implemented for soccer robot system. The efficiency and applicability of the proposed multiple-robot control algorithm using Petri-Net are demonstrated through 5vs5 Middle League SimuroSot soccer game.

• Communications for Statistical Applications and Methods
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• v.31 no.4
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• pp.365-375
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• 2024

Diverse methods to evaluate the prediction model of a time to event have been proposed in the context of right censored data where all subjects are subject to be susceptible. A time-dependent AUC (area under curve) measures the predictive ability of a marker based on case group and control one which are varying over time. When a substantial portion of subjects are event-free, a population consists of a susceptible group and a cured one. An uncertain curability of censored subjects makes it difficult to define both case group and control one. In this paper, our goal is to propose a time-dependent AUC for a cure rate model when a censoring distribution is related with covariates. A class of inverse probability of censoring weighted (IPCW) AUC estimators is proposed to adjust the possible sampling bias. We evaluate the finite sample performance of the suggested methods with diverse simulation schemes and the application to the melanoma dataset is presented to compare with other methods.

• Journal of the Society of Naval Architects of Korea
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• v.47 no.2
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• pp.248-257
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• 2010

In this study, a discrete event and dynamic-based discrete time combined simulation modeling architecture, which can be used to calculate equations of motions among discrete events, is developed. This is composed of a command model, which is in charge of discrete event simulation, a numerical integration model, which finds motions by numerically integrating equations of motions, and an external force and control force model, which calculates the force and transmits it to the equations. Using this architecture, we can develop dynamic-based simulation by simply connecting and combining models, and handle simultaneously discrete event and discrete time simulation. To verify the efficiency of the architecture, it is applied to the submarine diving and surfacing simulation.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.348-352
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• 1993

A hybrid system contains both continuous variables and discrete event components. This paper presents the new control architecture for hybrid systems, which consists of a conventional controller for the continuous-time variable of the system, a supervisor for discrete event components of the system, and an interface for link between the controller and the plant. The presented controller is suitable for the system operating at the different operating conditions or for system being changing the plant model by enabling and disabling discrete events. This paper shows that the presented controller is better than the conventional controller.

• Journal of the Korea Society for Simulation
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• v.21 no.4
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• pp.35-46
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• 2012

As complexity of real-time systems is being increased ad hoc approaches to analysis of such systems would have limitations in completeness and coverability for states space search. Formal means using a model-based approach would solve such limitations. This paper proposes a model-based formal method for logical analysis, such as safety and liveness, of real-time systems at a discrete event system level. A discrete event model for real-time systems to be analyzed is specified by DEVS(Discrete Event Systems Specification) formalism, which specifies a discrete event system in hierarchical, modular manner. Analysis of such DEVS models is performed by Communicating DEVS (C-DEVS) formalism of a timed global state transition specification and an associated analysis algorithm. The C-DEVS formalism and an associated analysis algorithm guarantees that all possible states for a given system are visited in an analysis phase. A case study of a safety analysis for a rail road crossing system illustrates the effectiveness of the proposed method of the model-based approach.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.816-819
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• 1996

This paper focuses on development of simulation model for SAE J1850 and performance evaluation of a J1850 network. The simulation model has been developed by using discrete event simulation language. SAE J1850 is one of Class B network protocol for general data sharing applications. Through numerous simulation experiments, several important performance factors such as the probability of a successful transmission, average queue delay, and throughput have been evaluated.