• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.1
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• pp.33-38
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• 1994

In this paper, waveguide banpass filters using H-plane step discontinuities are designed based on the field theory analysis and optimization of the resonator lengths as well as dimensions of discontinuities, instead of the conventional synthesis method based on the equivalent circuit. The waveguide inductive obstacles introduced by H-plane step discontinuities analyzed using mode-matching method and the generalized scattering parameters are derived. Using the derived scattering parameters of the discontinuities as well as those of resonators, waveguide bandpass filters are designed through optimization method, modified Razor search method proposed by J.H.Bandler. Using this design procedures, waveguide bandpass filters are designed and tested at X-band(center frequency 10GHz) as well as Ka-band(center frequency 35GHz).

• Progress in Superconductivity and Cryogenics
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• v.25 no.1
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• pp.16-20
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• 2023

The International Electrotechnical Commission (IEC) 61788-26:2020 provides guidelines for measuring the critical current of Rare-earth barium copper oxide (REBCO) tapes using two methods: linear ramp and step-hold methods. The critical current measurement criterion, 1 or 0.1 μV/cm of electric field from IEC 61788-26 has been normally applied to REBCO coils or magnets. No-insulation (NI) winding technique has many advantages in aspects of electrical and thermal stability and mechanical integrity. However, the leak current from the NI REBCO coil can cause distortion in critical current measurement due to the characteristic resistance which causes the radial current flow paths. In this paper, we simulated the NI REBCO coil by applying both linear ramp and step-hold methods based on a simplified equivalent circuit model. Using the circuit analysis, we analyzed and evaluated both methods. By using the equivalent circuit model, we can evaluate the critical current of the NI REBCO coil, resulting in an estimation error within 0.1%. We also evaluate the accuracy of critical current measurement using both the linear ramp and step-hold methods. The accuracy of the linear ramp method is influenced by the inductive voltage, whereas the accuracy of the step-hold method depends on the duration of the hold-time. An adequate hold time, typically 5 to 10 times the time constant (τ), makes the step-hold method more accurate than the linear ramp method.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.32-32
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• 2011

Plasma etching is used in microelectronic processing for patterning of micro- and nano-scale devices. Commonly, optical emission spectroscopy (OES) is widely used for real-time endpoint detection for plasma etching. However, if the viewport for optical-emission monitoring becomes blurred by polymer film due to prolonged use of the etching system, optical-emission monitoring becomes impossible. In addition, when the exposed area ratio on the wafer is small, changes in the optical emission are so slight that it is almost impossible to detect the endpoint of etching. For this reason, as a simple method of detecting variations in plasma without contamination of the reaction chamber at low cost, a method of measuring plasma impedance is being examined. The object in this research is to investigate the suitability of using plasma impedance monitoring (PIM) with statistical approach for real-time endpoint detection of $SiO_2$ etching. The endpoint was determined by impedance signal variation from I-V monitor (VI probe). However, the signal variation at the endpoint is too weak to determine endpoint when $SiO_2$ film on Si wafer is etched by fluorocarbon plasma on inductive coupled plasma (ICP) etcher. Therefore, modified principal component analysis (mPCA) is applied to them for increasing sensitivity. For verifying this method, detected endpoint from impedance analysis is compared with optical emission spectroscopy (OES). From impedance data, we tried to analyze physical properties of plasma, and real-time endpoint detection can be achieved.

• Journal of Korean Academy of Nursing
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• v.32 no.6
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• pp.897-905
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• 2002

The purpose of this study was to discuss and address the state of the knowledge development and the nature of knowledge regarding fatigue. Method: This study analyzed the 63 fatigue related articles published from 1990 to 2001. The analysis schema was 'Alternative linkages among philosophy, theory, and method for nursing science' (Kim, 1993). Result: The 63 articles had been studied only within 5 types among all 96 types of linkages. Most of the articles (59 among 63 articles) had been studied within scientific realism and deductive logic. Fifty-three articles among 59 articles were the type of explanatory and predictive theory, grasping reality by the etic method on the controlled setting. Conclusion: This study suggests more development of knowledge regarding fatigue with various logics, especially with discovery logic such as inductive and retroductive or methods in multiple designs on various subjects under various philosophy needed for nursing practice.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.4
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• pp.138-143
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• 2004

This paper analyzed harmonics from high speed railway traction to high speed railway substation and provide a reduction method of harmonics using the passive filter. A substation supplies the electric power to a train or can supply the electric power to several trains. According to the number of trains covered by a substation, characteristics of harmonics are investigated. These harmonics affect transformer heating and inductive interference. In order to get rid of the damage from the harmonics, this paper presented minimizing method of harmonics. The proposed method is verified in simulation using the PSCAD/EMTDC.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.123.2-123.2
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• 2013

Etching endpoint detection with plasma impedance monitoring (PIM) is demonstrated for small area dielectric layers inductive coupled plasma etching. The endpoint is determined by the impedance harmonic signals variation from the I-V monitoring system. Measuring plasma impedance has been examined as a relatively simple method of detecting variations in plasma and surface conditions without contamination at low cost. Cluster analysis algorithm is modified and applied to real-time endpoint detection for sensitivity enhancement in this work. For verification, the detected endpoint by PIM and real-time cluster analysis is compared with widely used optical emission spectroscopy (OES) signals. The proposed technique shows clear improvement of sensitivity with significant noise reduction when it is compared with OES signals. This technique is expected to be applied to various plasma monitoring applications including fault detections as well as end point detection.

• Journal of Power Electronics
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• v.13 no.5
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• pp.896-908
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• 2013

Under high grid impedance conditions, it is difficult to guarantee the stability of grid-connected inverters with an LCL filter designed based on ideal grid conditions. In this paper, the theoretical basis for output impedance calculation is introduced. Based on the small-signal model, the d-d channel closed-loop output impedance models adopting the converter-side current control method and the grid-side current control method are derived, respectively. Specifically, this paper shows how to simplify the stability analysis which is usually complemented based on the generalized Nyquist stability criterion (GNC). The stability of each current-controlled grid-connected system is analyzed via the proposed simplified method. Moreover, the influence of the LCL parameters on the stability margin of grid-connected inverter controlled with converter-side current is studied. It is shown that the stability of grid-connected systems is fully determined by the d-d channel output admittance of the grid-connected inverter and the inductive component of the grid impedance. Experimental results validate the proposed theoretical stability analysis.

• Korean Security Journal
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• no.15
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• pp.89-105
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• 2008

The aim of this study is to examine the primary causes of security guard's stress by conducting a survey of 50 guards engaging in security companies in Seoul and Gyeonggido. The following results are attained by an inductive content analysis of conviction interview data through in-depth interview of qualitative study method. 1. Factors of stress related to personal problems. The stress by personal problems is resulted from two factors. One is the physical strength inferiority, which leads to negative thoughts, dismay, mental conflict and tension. The other is complex about not-specializing security, which causes discord with his/her supervisor or co-workers and a feeling of uneasiness. 2. Factors of stress related to human relationship. The stress due to human relations is constantly resulted from discord with his/her supervisor and inclined to be accumulated. The mental conflict is elated in feeling that the manager's instructions are not right. So this factor makes them want change of occupation. Also working conditions are different from those of their friends, which causes them not to spend a lot of time with their friends. 3. Factors of stress related to domestic life It appears that most security guards are under stress due to their spouses' discontent with a small number of wages. Also it is reported that male guards are under stress in case of unhappy conjugal relations. And security guard's life is restricted much more than that of workers in a general occupation because of standing ready for mobilization and 24-hour service. So some of male guards experienced an early symptoms of a morbid suspicion about their wife's chastity and are suffering from insomnia as an occupational disease.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.2
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• pp.177-186
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• 2012

In this paper, we propose a design method that the crosstalk of probe connector pins satisfy the limitation of -30 dB. The parameters(inductance and capacitance) were extracted in the grid-structured probe connector pin system, and it is shown that the new parameters are easily calculated with increasing ground pin numbers using the previously calculated parameters. In addition, the crosstalk reduction algorithm by employing more grounds around the signal pin has been suggested, and it is confirmed that the suggested method is quite effective especially for the reduction of inductive couplings. Finally, we suggested the correlation between the pitch and the length of the pins to satisfy the crosstalk limitation of -30 dB with the given number of ground pins, which will be quite useful when design a probe connector pin system.

• International Journal of Computer Science & Network Security
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• v.22 no.8
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• pp.385-391
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• 2022

The relevance of the published study lies in the fact that since the introduction of the first Global Distribution System, new information and communication technologies have constantly been changing the tourism industry. In the context of a current digital environment, travel agencies can't avoid participating in digital transformation processes aimed at rethinking operational models, skills, and organisational structures in the regions. This publication aims to present and provide a critical overview of digitalisation processes in tourism development in the regions of the Russian Federation, as well as to reflect on the challenges to the widespread digitalisation processes in the regional tourism sector. The subject of research is digitalisation processes, as they radically transform the modern tourism industry, in the regions as well. The pragmatic research paradigm was considered the most appropriate for the study of tourism digitalisation processes in the regions, as it does not require the selection of a specific theoretical basis for data collection. The pragmatic approach forms an alternative to classical theoretical approaches and serves as a particular type of grounded theory, combining both inductive and deductive methods. No software was used for the inductive part of the analysis. The deductive part was conducted using the qualitative data analysis software Nvivo 11. Given the wide diversity of interested parties in the regional tourism digital area, a stratified purposive sampling method was preferred due to its ability to adequately represent the full picture of the phenomenon under study. The selection and stratum criteria were chosen to maximise the representation of different perspectives in the regional tourism digital area. The novelty of the study is due to the digitalisation processes, with an implication of new needs, while opening up promising opportunities for more productive tourism business in the regions of the Russian Federation. Currently, e-tourism in the Russian Federation has become a subject of lively debate among scholars and practitioners. However, the involvement of advanced digitalisation technologies in the field of information processes in the regions of the Russian Federation is of a very sporadic character.