• Journal of the Korean Data and Information Science Society
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• v.18 no.2
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• pp.315-326
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• 2007

The rapid proliferation of wireless networks and mobile computing applications has changed the landscape of network security. Anomaly detection is a pattern recognition task whose goal is to report the occurrence of abnormal or unknown behavior in a given system being monitored. This paper presents a dynamic anomaly detection scheme that can effectively identify a group of especially harmful internal masqueraders in cellular mobile networks. Our scheme uses the trace data of wireless application layer by a user as feature value. Based on the feature values, the use pattern of a mobile's user can be captured by rough sets, and the abnormal behavior of the mobile can be also detected effectively by applying a roughness membership function with both the age of the user profile and weighted feature values. The performance of our scheme is evaluated by a simulation. Simulation results demonstrate that the anomalies are well detected by the proposed dynamic scheme that considers the age of user profiles.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.111.3-111
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• 2001

Automative system and robot are operated by motor. Recently, automative system and robot need correct operation and control for precise task. Therefore they need precise motor control technology. In present, controller needs precise motor control technology in automative system and robot. Usual step motor driver that has 200 steps per revolution is not proper. So we need micro step motor driver that is more precise then usual step motor driver. In this paper, micro step motor driver is used for precise control of step motor. The goal is precise operation and location control. This micro step motor driver is A3972SB that is made in Alloegro Company. It has serial port that receives two 6-bits linear DAC value. Almost all systems generate DAC value with micro processer and ...

• 제어로봇시스템학회:학술대회논문집
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• 1990.10b
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• pp.1150-1155
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• 1990

This paper proposes an optimal redundancy resolution of a kinematically redundant manipulator while considering homotopy classes. The necessary condition derived by minimizing an integral cost criterion results in a second-order differential equation. Also boundary conditions as well as the necessary condition are required to uniquely specify the solution. In the case of a cyclic task, we reformulate the periodic boundary value problem as a two point boundary value problem to find an initial joint velocity as many dimensions as the degrees of redundancy for given initial configuration. Initial conditions which provide desirable solutions are obtained by using the basis of the null projection operator. Finally, we show that the method can be used as a topological lifting method of nonhomotopic extremal solutions and also show the optimal solution with considering the manipulator dynamics.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.261-267
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• 2010

Present maintenance of a high speed railway is after the fack maintenance that executes a task when measured value goes over threshold value except some planned maintenance. It is difficult from efficient management of maintenance human resource and equipment commitment because it is difficult to predict quantity of maintenance targets. Corrective maintenance is pushed back on the repair priority of other target to need repair and it is exceeded repair cost potentially. For safety and dependable track management because track deterioration prediction is linked directly with track's life and safety of train service, it is very important that track management be based on preventive maintenance. In this study, we propose statistics model of track quality to use track inspection data and forecast model for track deterioration prediction.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1996.10a
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• pp.219-222
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• 1996

During the navigation of mobile robot, one of the essential task is to determination the absolute location of mobile robot. In this paper, we proposed a method to determine the position of the camera from a landmark through the visual image of a quadrangle typed landmark using neural network. In determining the position of the camera on the world coordinate, there is difference between real value and calculated value because of uncertainty in pixels, incorrect camera calibration and lens distortion etc. This paper describes the solution of the above problem using BPN(Back Propagation Network). The experimental results show the superiority of the proposed method in comparison to conventional method in the performance of determining camera position.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1997.11a
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• pp.165-170
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• 1997

During the navigation of mobile robot, one of the essential task if to determine the absolute position of mobile robot. In this paper, a method to determine the position of the camera using a vanishing point and neural networks without landmark if proposed. In determining the position of the camera on the world coordinate, there are differences between the real value and the calculated value because of uncertainty in pixels, incorrect camera calibration and lens distortion etc. This paper describes the solution of the above problem using BPNN(Back Propagation Neural Network) and experimental results show the capability to adapt for a mobile robot.

• Publications of The Korean Astronomical Society
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• v.22 no.4
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• pp.97-101
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• 2007

We are often faced with the task of having to estimate the hydrogen and helium ionizing luminosities of massive stars in the study of H II regions and the warm ionized medium (WIM). Using the results of the most complete compilation of stellar parameters (the effective temperature, stellar radius and surface gravity) and the latest Kurucz stellar atmosphere models, we calculate the ionizing photon luminosities in the $H^0\;and\;He^0$ continua from O3 to B5 stars. We compared the theoretical Lyman-continuum luminosity with the observationally inferred luminosity of the H II region around ${\alpha}$ Vir, and found that the theoretical value is higher than the observed value in contrast to the eariler result.

• Proceedings of the KIEE Conference
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• 1993.07a
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• pp.399-402
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• 1993

In this paper, an inverse kinematics of redundant manipulators is proposed. Optimality-constraint based inverse kinematic algorithms have some problems because those algorithms are based on necessary conditions for optimality. Among the problems, switching from a maximum value to a minimum value may occur and make an inverse kinematic solution unstable while performing a given task. An inverse kinematic solution for protecting from the switchings is suggested. By sufficient conditions for optimality, the configuration space is defined as a set of regions, potentially good configuration region and potentially bad configuration region. Inverse kinematics solution within potentially good configuration region can provide joint trajectories without both singularities and switchings. Through a simulation of tracing a circle, we show the effectiveness of this inverse kinematics.

• The Korean Journal of Archival Studies
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• no.12
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• pp.37-80
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• 2005

Archival appraisal has been a significant field and demanding task in thoughts and practice about modern archive, in particular, because of insufficiency of resources for the preservation in comparison with the large scale of recorded information. Appraising records does naturally go with the selecting and acquiring them. In the field of appraisal, however, comprehensive accountability on appraisal is much more important than selection and acquisition. The purpose of this study is the proposition of the theoretic approach to the analysis of the factors concerning the archival appraisal. For this purpose, I would try not the actual practice of the archival appraisal but theoretical categories of archival appraisal decision. The archival Characteristic, Value, and Context will be proposed as theoretical categories for the analysis of archival appraisal decision. Firstly, Characteristic category makes it clear to identify the reliable and authentic records, and then, Value provides us with elucidation about the appraisers' recognition of values. Lastly, Context explains the priority of selection throughout creating, using, interrelationship, and social meaning of archives.

• The Journal of Society for e-Business Studies
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• v.17 no.1
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• pp.1-21
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• 2012

Conventional studies on technology acceptance have focused on information technology for utilitarian value and hence based on 'theory of reasoned action'. Correspondingly, the studies depend on perceived usefulness and perceived ease of use as rational decision making elements. However, in ubiquitous society, innovative technologies are applied to non-task area, as well as task-oriented area. Therefore, users are more influenced by affective factors than cognitive factors in causing their usage intention. In line with those discussions, we cannot make sure that the conventional technology acceptance model could fully explain the current u-service acceptance phenomenon. Hence, to overcome the limitations of the prior technology acceptance studies, we propose an amended TAM which includes one hedonic factor and two factors on ubiquitous computing technology : ubiquity and intelligence.