• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2016.05a
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• pp.186-188
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• 2016

전자항법시대의 도래로, 항해사의 의사결정시 항해설비 의존도는 점차 증가하고 있으며, 국제협약에 의해 ECDIS(전자해도 정보시스템)의 강제화로 전자항해설비 사용을 위한 친숙화는 필수적이다. 국제사회에서도 항해사 및 도선사들이 항해설비의 친숙한 사용을 도모하기 위한 표준이 필요함을 인식하고, 2015년 6월 IMO MSC 95차에서 항해설비에 표준모드 적용을 위한 S-Mode 가이드라인 개발이 2019년까지의 e-Navigation 주요개발 과제로 승인되었다. S-Mode는 주요 사용자인 항해사, 선장 및 도선사에게 표준화된 화면, 기능 제공을 통해 친숙한 업무환경을 통해 상황인식에 기여함으로써 항해안전성을 향상시키고, 교육 훈련 측면에서의 선원의 부담을 경감시키기 위한 목적으로 개발 예정이다. S-Mode 가이드라인 개발을 위해서, HCD(인간중심적 설계)에 기반 하여, 항해설비에 대한 인적측면에서의 개선이 이루어질 것으로 예상된다. 본 연구에서는 ECDIS를 활용하여 S-Mode 가이드라인 개발을 위한 주요 방안 및 항해화면의 개선방안을 연구하였다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2018.11a
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• pp.313-315
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• 2018

S-Mode는 항해에 필요한 정보들을 확인하기 위하여 주요 항해장비의 기능과 화면, 작동법등을 표준화하는 기능이다. 국제해사기구는 S-Mode의 항해장비 적용을 위한 가이드라인 개발을 진행 중에 있다. 본 연구는 S-Mode 적용을 위한 사용자 의견과 선호도를 조사하여 지침 개발에 반영하기 위해 수행되었다. 항해장비 중 ECDIS를 대상으로, 사용자 선호도 조사를 위한 테스트 프로그램을 구성하였다. 웹기반의 테스트 프로그램을 통해 선호도 조사를 실시하였으며, ECDIS 사용자들이 항해당직 수행 시 선호하는 정보의 내용과 화면배치를 확인하였다. 연구의 결과는 S-Mode에 고려할 사용자 요구 사항을 제시함으로써, 실효성 있는 지침 개발에 기여할 수 있을 것이다.

• Tribology and Lubricants
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• v.36 no.3
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• pp.117-123
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• 2020

In this study, the effect of the pre-mild wear mode test condition on the subsequent severe wear behavior of carbon steel has been investigated when the wear mode is varied according to the sliding speed change during sliding contact. Two sliding speeds of 0.3 m/s and 3 m/s for the mild wear mode test have been chosen and a sliding speed of 1 m/s for the severe wear mode test. A mild wear mode test at two different sliding speeds has been carried out during the severe wear mode test and total sliding distance of the mild wear mode test has been changed at this time. As a result, it could be found that the wear rate of carbon steel under the severe wear mode test after performing a pre-mild wear mode test is significantly reduced, compared with that before performing. However, its wear rate was slightly higher than that under the mild wear mode test. Oxides produced during the pre-mild wear mode test have been found to play a significant role in reducing the wear rate under the subsequent severe wear mode test. In particular, it was found that the effect of a pre-mild wear mode test performed at the sliding speed of 3 m/s has more rapid and the reduction in the wear rate was greater than thst at the sliding speed of 0.3 m/s.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2015.07a
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• pp.124-126
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• 2015

e-Navigation의 전략이행계획(SIP)에서 S-Mode기능은 관련 설비에 적용하기로 결정되었으며, 표준화(Standardized)된 디스플레이, 기능 및 공통 인터페이스를 사용자에게 제공하여 항해안전성을 향상시키고자 도입되었다. 본 연구는 S-Mode 관련 기준 개발에 있어 초기 단계에서부터 사용자의 요구사항과 기대를 반영하기 위한 기초연구로 주사용자인 항해사를 대상으로 S-Mode의 필요성과 표준화의 범위, 개발에 고려하여야 할 우선순위 요소에 대한 설문조사를 실시하고 그 내용을 분석하였다. 연구의 결과는 e-Navigation 이행 시 선박 항해설비 전반에 적용될 S-Mode 개념 및 기능에 대한 개념을 구체화하고, 개발에 고려할 세부요소들을 제시하여 관련 기술개발에 도움이 될 것으로 기대된다.

• International Journal of Concrete Structures and Materials
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• v.9 no.4
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• pp.475-486
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• 2015

Mode II fracture toughness ($K_{IIc}$) of fiber reinforced concrete (FRC) has been widely investigated under various patterns of test specimen geometries. Most of these studies were focused on single type fiber reinforced concrete. There is a lack in such studies for hybrid fiber reinforced concrete. In the current study, an experimental investigation of evaluating mode II fracture toughness ($K_{IIc}$) of hybrid fiber embedded in high strength concrete matrix has been reported. Three different types of fibers; namely steel (S), glass (G), and polypropylene (PP) fibers were mixed together in four hybridization patterns (S/G), (S/PP), (G/PP), (S/G/PP) with constant cumulative volume fraction ($V_f$) of 1.5 %. The concrete matrix properties were kept the same for all hybrid FRC patterns. In an attempt to estimate a fairly accepted value of fracture toughness $K_{IIc}$, four testing geometries and loading types are employed in this investigation. Three different ratios of notch depth to specimen width (a/w) 0.3, 0.4, and 0.5 were implemented in this study. Mode II fracture toughness of concrete $K_{IIc}$ was found to decrease with the increment of a/w ratio for all concretes and test geometries. Mode II fracture toughness $K_{IIc}$ was sensitive to the hybridization patterns of fiber. The (S/PP) hybridization pattern showed higher values than all other patterns, while the (S/G/PP) showed insignificant enhancement on mode II fracture toughness ($K_{IIc}$). The four point shear test set up reflected the lowest values of mode II fracture toughness $K_{IIc}$ of concrete. The non damage defect concept proved that, double edge notch prism test setup is the most reliable test to measure pure mode II of concrete.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.12
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• pp.963-968
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• 2018

In this paper, a compact common mode filter using passive elements is designed and fabricated. To design a common mode filter with required frequency response, the equivalent circuits of the common mode filter in differential mode and common mode were analyzed. Compared with the former filter using a ${\lambda}/4$ resonator, the size of the proposed structure was reduced by 60 %. The fabricated common mode filter has a maximum differential mode insertion loss of 1.2 dB and a minimum common mode absorption efficiency of 78.2% in the CMA - bandwidth of 27.5 %.

• Journal of Ocean Engineering and Technology
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• v.22 no.1
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• pp.6-12
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• 2008

The dispersion and attenuation of Lamb and Leaky Lamb waves propagating in a 1 mm-thick steel plate were investigated. For acquiring a long(or large) range inspection capability, the fundamental symmetric and anti-symmetric wave modes(S0 and A0) over law frequencies were studied. Based on the dispersion curves, as well as pitch-catch and multi-mode simulations, it was shown that the S0 mode over law frequencies is the proper mode to minimize the dispersion and attenuation. In addition, it was shown that the S0 mode couldbe easily distinguished under multi-mode simulation since it has a larger group velocity than the A0 mode.

• Korean Chemical Engineering Research
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• v.57 no.5
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• pp.735-742
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• 2019

In this work, the electrokinetic interactions between the undulated structure of an ion-selective membrane and electroconvective instability has been studied using numerical analysis. Using finite element method, electric field-ionic species transport-flow field were analyzed by fully-coupled manner. Through the numerical study, the Dukhin's mode as the mechanism of undulated surface for the electroconvective instability were proven. The Dukhin's mode which competes with Rubinstein's mode has roles of (i) decreasing transition voltage to overlimiting regime and (ii) non-linearly increasing of overlimiting current. Also, (iii) the mixing efficiency is enhanced by removal mechanism of high-frequency Fourier mode of the electroconvective instability. Conclusively, the undulated ion-selective surface would provide energy-efficient mechanism for ion-selective transport systems such as electrodialysis, electrochemical battery, etc.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.11
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• pp.114-127
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• 2016

The competition among nations has been extended to competition between localities, and the importance of knowledge activities in local areas is being emphasized. To contribute to the nurturing of highly qualified professionals and the development of local industry, the Korean government established the S&T-centric research universities including KAIST in 5 local areas. These S&T-centric research universities are top notch research centers and educational environments in Korea. However, it has been pointed out that their ability to act as local innovation hubs is limited. Accordingly, this study conducted an empirical analysis on the outcomes of the S&T-centric research universities by dividing them into two categories, Mode 1 and Mode 2, and comparing them with those of other general universities. It was found that the outcomes of the S&T-centric universities were higher in Mode 1, but lower in Mode 2, than those of the general universities. Furthermore, the S&T-centric universities are not connected very much to the region's specialized industries. It was difficult to find any evidence that the S&T-centric universities differ from the other universities in terms of their outcomes or activities as they were initially envisaged.

• Journal of the Korean Society for Nondestructive Testing
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• v.29 no.5
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• pp.442-449
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• 2009

An investigation has been made on the relationship between characteristics of torsional mode signal in MsS and SH mode signal in BEM modeling for the defect of stainless steel pipe. In order to compare torsional mode signal with SH mode signal of defect in stainless steel pipe, specimens were made by changing size of depth and width along to circumferential direction 360 degrees. All the defects was detected by torsional mode signal of MsS, especially according to the change of depth size, amplitude of signal was changed. But width change for the circumferential defects has no certain tendency. SH mode signal of BEM modeling shows similar results with torsional mode, with change makes amplitude variation of signal. In this paper, the characteristics of torsional mode and SH mode signals were found. It is possible to predict the circumferential defects for the pipe by SH mode modeling.