• The Transactions of the Korean Institute of Electrical Engineers D
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• v.52 no.4
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• pp.189-197
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• 2003

The problem of designing a parallel feedforward compensator (PFC) is considered for a class of non-square linear systems such that the closed-loop system is strictly passive. If a given square system has (vector) relative degree one and is weakly minimum phase, the system can be rendered passive by a state feedback. However, when the system states are not always measurable and the given output is considered, passivation (i.e. rendering passive) of a non-minimum phase system or a system with high relative degree cannot be achieved by any other methodologies except by using a PFC. To passivate a non-square system we first determine a squaring gain matrix and design a PFC such that the composite system has relative degree one and is minimum phase. Then the system is rendered strictly passvie by a static output feedback law. Necessary and sufficient conditions for the existence of the PFC and the squaring gain matrix are given by the static output feedback formulation, which enables to utilize linear matrix inequality (LMI). As an application of the scheme, an alternative way of replacing the role of velocity measurements is provided for the PD-control law of a convey-crane system.

• Journal of the Korean institute of surface engineering
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• v.51 no.6
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• pp.421-429
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• 2018

In this study, various electrochemical experiments were carried out to compare the corrosion characteristics of AA5052-O, AA5083-H321 and AA6061-T6 in seawater. The electrochemical impedance and potentiostatic polarization measurements showed that the corrosion resistance is decreased in the order of AA5052-O, AA5083-H321 and AA6061-T6, with AA5052-O being the highest resistant. This is closely associated with the property of passive film formed on three tested Al alloys. Based on the slope of Mott-Schottky plots of an n-type semiconductor, the density of oxygen vacancies in the passive film formed on the alloys was determined. This revealed that the defect density is increased in the order of AA5052-O, AA5083-H321 and AA6061-T6. Considering these facts, it is implied that the addition of Mg, Si, and Cu to the Al alloys can degrade the passivity, which is characterized by a passive film structure containing more defect sites, contributing to the decrease in corrosion resistance in seawater.

• Corrosion Science and Technology
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• v.22 no.6
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• pp.478-483
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• 2023

This study examined the corrosion behavior of bimetal materials composed of Fe-Ni alloy and Fe-Ni-Mo alloy, both suitable for use in electromagnetic switches. Electrochemical polarization and weight loss measurements revealed that, in contrast to Fe-Ni alloy, which exhibited pseudo-passivity behavior, Fe-Ni-Mo alloy had higher anodic current density, displaying only active dissolution and greater weight loss. This indicated a lower corrosion resistance in the Fe-Ni-Mo alloy. Equilibrium calculations for the phase fraction of precipitates suggested that the addition of 1 wt% Mo may lead to the formation of second-phase precipitates, such as Laves and M₆C, in the γ matrix. These precipitates might degrade the homogeneity of the passive film formed on the surface, leading to localized attacks during the corrosion process. Therefore, considering the differences in corrosion kinetics between these bimetal materials, the early degradation caused by galvanic corrosion should be prevented by designing a new alloy, optimizing heat treatment, or implementing periodic in-service maintenance.

• English Language & Literature Teaching
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• v.15 no.3
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• pp.1-31
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• 2009

Although Korean university students' primary concern is academic success in their higher degrees in the UK, they highly desire to develop English communicative competence through a number of opportunities to speak with natives speakers. The paper aims at examining to what extent they are able to be socialised into a new environment while they are studying at UK universities. The in-depth, longitudinal interviews with the targeted group of six Korean masters' students at the University of York was undertaken to observe the pace of their progress in developing social skills. Reluctance and hesitance to contact and interact with their supervisors and other academic staff persisted for most of them to the final term caused by cultural reasons such as face and hierarchy rather than language problems. Despite the six participants' variation in their patterns of social interaction, they struggled with pressures towards monoculture-biased interaction with Korean people, which was quite extreme for the five participants. This passivity can be explained by several reasons such as the students' lack of communicative competence and other situational factors on one-year course. It is important to note that students' failure to develop network with native speakers is strongly associated with experience of cultural withdrawal and frustration with developing communicative competence in English.

• Journal of Korean Academy of Nursing Administration
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• v.9 no.3
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• pp.329-335
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• 2003

Purpose: The purpose of this paper was to inquiry a philosophical foundation for the nursing ethics according to the Levinas' ethics which had emphasis on face to face interpersonal relationship and responsibility for the vulnerable other. Method: First of all, for the foundation of nursing ethics, a understanding of human vulnerability was a starting point; the nurse's bodily sensibility was regarded as a basis for the possibility of the ethical interpersonal relationship. Then, based on Levinas's ethics, it was explained how the moral responsibility for the calling of the suffering other could occur in nursing situation. Result: Nursing implied the altruistic ethical dimension on the subject of the responsibility for the vulnerable other. A nurse as ethical subject in her sensitive passivity is affected by the suffering other and exposed to the other. A nurse herself/himself has to response to the ethical demand of suffering other and to take responsibility for it. After all, based on the Levinas's ethics, the ethical interpersonal relationship could be characterized as the face to face relation, and responsibility for the suffering other. Conclusion: In view of that, his ethical approach could be a proper theory for the explanation of the face to face relationship and altruistic feather of the nursing ethics based human bodily sensibility.

• Archives of design research
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• v.13 no.4
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• pp.185-194
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• 2000

The aim of copy writing is the communication between sender and receiver. The method of communication is language, which reflect the character of the culture of the community. And also the cultural difference owe to the linguistic difference. So, if we reflect this characters of the culture upon the copy of advertisement, it could be more effective. This is a study on Korean communicational expressions in the copy of advertisement. The copy is a communicational expression, the types of it differ the difference of culture and language. We can consider the type of Korean communicational expression as the expression of emotion, honors, authority, community, and passivity. In this study, we analyzed the real copy of advertisement, investigated how did the communicational expression appear in it and saw the result of analysis. we proposed next subjects in order to the more effective advertisement.

• International Journal of Contents
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• v.10 no.2
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• pp.18-27
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• 2014

This study examines underlying factors that influence undergraduate students' willingness to enhance communication with their instructor by comparing the frequency of e-mail and face-to-face interaction between students and instructors. Data was collected through a survey of 322 undergraduate journalism students at a large Midwestern university. The findings showed that the more passive students were in expressing their opinion during the class, the less likely they were to send e-mails to their instructor (Coef. = -0.180, p < .01) or to communicate with their instructor face-to-face (Coef. = -0.262, p < .01). The findings also showed that the more students described their personality as "shy," the less likely they were to e-mail their instructor (Coef. = -0.157, p < .05) or communicate with their instructor face-to-face (Coef. = -0.210, p < .01). It is noteworthy that the degrees of both passivity and shyness had a more negative effect on the probability of face-to-face interaction than they did on email interaction. In summary, email usage follows similar broader patterns of social interaction, rather than introducing a different trend in communication. This finding implies that the importance of e-mail should not be exaggerated as a communication tool for reticent students.

• Journal of the Korean Society for Heat Treatment
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• v.15 no.2
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• pp.76-81
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• 2002

The melt-spun amorphous $Fe_{77-X}P_{13}C_4B_4Al_2Mo_X$(x=4~10) and $Fe_{82-X}P_XC_4B_4Al_2Mo_8$(x=9~15) alloys were found to exhibit a large supercooled liquid region(${\Delta}T_x$) exceeding 40 K before crystallization. The largest ${\Delta}T_x$ for the glassy alloys containing Mo reaches as large as 65 K for the $Fe_{69}P_{13}C_4B_4Al_2Mo_8$ alloy. The corrosion behavior of the amorphous $Fe_{77-X}P_{13}C_4B_4Al_2Mo_X$(x=4~15) and $Fe_(82-X)P_XC_4B_4Al_2Mo_8$ (x=9~17) alloys were examined by electrochemical measurements in 9M $H_2SO_4$ solution at 303 K. The addition of Mo(or P) for replacing some portion of Fe is effective in improving the corrosion resistance of the investigated Fe-based glassy alloys. They are spontaneously passivated and have a wide passive region with low passive current density.

• Journal of the Korean institute of surface engineering
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• v.48 no.6
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• pp.343-348
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• 2015

In this paper, arc Zn thermal spray coating was carried out on the SS400 steel, and then various electrochemical characteristics and surface damage behavior of Zn thermal spray coating layer were analyzed. As the results, the potential of Zn thermal spray coating layer presented driving voltage above 300 mV compare to that of SS400 steel. The passivity characteristic in anodic polarization curve was not presented. It was adequate to as sacrificial anode material. In the surface damage after galvanostatic experiments, uniform corrosion tendency of Zn thermal spray coating layer was clearly observed with acceleration of the dissolution reaction. In conclusion, Zn thermal spray coating could be determined to represent the corrosion protection effect by stable sacrificial anodic cathodic protection method in seawater because it had sufficient driving voltage and uniform corrosion damage tendency for the SS400 steel.

• The Journal of Korea Robotics Society
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• v.8 no.3
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• pp.186-196
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• 2013

Since its introduction (e.g., [4, 6]), virtual coupling technique has been de facto way to connect a haptic device with a virtual proxy for haptic rendering and control. However, because of the single dependence on spring-damper feedback action, this virtual coupling suffers from the degraded transparency particularly during contact tasks when large device/proxy-forces are involved. In this paper, we propose a novel virtual coupling technique, which, by utilizing passive decomposition, reduces device-proxy position deviation even during the contact tasks while also scaling down (or up) the apparent inertia of the coordinated device-proxy. By doing so, we can significantly improve transparency between multiple degree of freedom (possibly nonlinear) haptic device and virtual proxy. In other to use passive decomposition, disturbance observer of [3] is adopted to estimate human force with some dead-zone modification to avoid "winding-up" force estimation in the presence of device torque saturation. Some preliminary experimental results are also given to illustrate efficacy of the proposed technique.