• 한국항해항만학회지
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• 제32권3호
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• pp.199-205
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• 2008

오늘날 정보기술은 항만 운영을 위한 필수적인 기술에 해당되며, 항만의 경쟁력을 가늠하는 척도로도 항만의 정보화 수준은 매우 중요한 가치를 지닌다. 그러나, 항만의 정보화 수준에 대한 연구는 아직까지 매우 부족하고, 최근의 수행된 선행연구의 경우에도 정보화 수준을 평가하는 지수를 개발하는데 주안점을 두고 있어, 컨테이너 터미널들의 실질적인 정보화 수준의 측정과 분석에 관한 연구가 결여되었다. 본 연구에서는 이러한 점에 주목하여, 우리나라 주요 터미널의 정보화 수준을 분석하고, 몇 가지 시사점을 제시하는 것을 연구의 목적으로 한다. 특히, 본 연구에서는 선행연구의 지수모델에서 고려되지 못했던 계층간 상호중복성 등을 고려하여 보다 명확한 지수모델을 수립하여 주요 컨테이너 터미널의 정보화 수준을 분석하였다.

• 정보관리학회지
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• 제33권3호
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• pp.7-29
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• 2016

연구자 성과 평가를 위해 널리 사용되는 h-지수는 일관성 부족 문제와 공저자 수를 고려하지 않는다는 문제를 가지고 있다. 이를 극복하기 위해 h-지수와 g-지수, 그리고 공저 보정 방안을 검토하고 2004년부터 2013년 사이의 실제 KCI 데이터를 대상으로 분석해본 결과는 다음과 같다. 첫째, 일관성 결여 문제를 해소하기 위해서는 g-지수를 사용하는 것이 더 바람직하다고 판단된다. 둘째, 연구 성과의 양적인 측면과 질적인 측면을 한꺼번에 반영하는 복합 지수라는 h-지수와 g-지수의 고유한 특성을 유지하기 위해서는 반드시 공저를 보정하여 지수를 측정해야 한다. 셋째, 공저자 수로 나눈 인용빈도를 사용하는 $h_C$-지수와 $g_C$-지수를 적용하면 단독 저술 비중이 높은 인문학 분야 연구자도 공정하게 평가할 수 있고, 특정 분야나 특정 기관에 속한 연구자가 상위 순위를 과점하는 현상을 방지할 수 있다.

• Journal of information and communication convergence engineering
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• 제8권4호
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• pp.377-382
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• 2010

With the advent of flash memory based new storage device (SSD), there is considerable interest within the computer industry in using flash memory based storage devices for many different types of application. The dynamic index structure of large text collections has been a primary issue in the Information Retrieval Applications among them. Previous studies have proven the three approaches to be effective: In- Place, merge-based index structure and a combination of both. The above-mentioned strategies have been researched with the traditional storage device (HDD) which has a constraint on how keep the contiguity of dynamic data. However, in case of the new storage device, we don' have any constraint contiguity problems due to its low access latency time. But, although the new storage device has superiority such as low access latency and improved I/O throughput speeds, it is still not well suited for traditional dynamic index structures because of the poor random write throughput in practical systems. Therefore, using the experimental performance evaluation of various index maintenance schemes on the new storage device, we propose an efficient index structure for new storage device that improves significantly the index maintenance speed without degradation of query performance.

• Structural Engineering and Mechanics
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• 제67권4호
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• pp.327-336
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• 2018

In this study, an efficient damage index is proposed to identify multiple damage cases in structural systems using the concepts of frequency response function (FRF) matrix and strain energy of a structure. The index is defined based on the change of strain energy of an element due to damage. For obtaining the strain energy stored in elements, the columnar coefficients of the FRF matrix is used. The new indicator is named here as frequency response function strain energy based index (FRFSEBI). In order to assess the performance of the proposed index for structural damage detection, some benchmark structures having a number of damage scenarios are considered. Numerical results demonstrate that the proposed index even with considering noise can accurately identify the actual location and approximate severity of the damage. In order to demonstrate the high efficiency of the proposed damage index, its performance is also compared with that of the flexibility strain energy based index (FSEBI) provided in the literature.

• 한국항행학회논문지
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• 제22권5호
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• pp.375-383
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• 2018

정지한 객체의 측위에 사용되던 Network RTK (real time kinematics) 기술을 이동형 항체의 항법에 적용하기 위해서는 보정정보와 함께 사용자의 성능을 대표할 수 있는 지표가 함께 제공되어야 한다. 이를 위하여 본 논문에서는 I95 (ionospheric index 95) / G95 (geodetic index 95), SBI (semivariance based index), RIU (residual interpolation uncertainty) 등의 지표 도출 알고리즘을 분석하고 이를 국토지리정보원의 기준국 원시 데이터와 VRS (virtual reference station) 사용자에 적용함으로써 정밀 항법 성능 지표로의 활용 가능성을 타진하였다. 24시간 데이터를 처리한 결과 보정정보의 비선형성을 나타낼 수 있는 RIU 지표와 Network RTK 사용자의 위치 정확도와의 상관성이 0.52로 타 지표에 비해 훨씬 높은 것으로 나타났으므로 향후 이동 항체의 항법 성능 지표로 사용이 가능할 것으로 예상된다.

• 대한전기학회논문지
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• 제41권2호
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• pp.144-155
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• 1992

A design of a highly stable current-controlled power supply combining the phase-controlled rectifier (PCR), passive filter and active filter is investigated. A digital phase-looked voltage control (PLVC) with a capability of compensating the thyristor firing angles under unvalanced power source is proposed` otherwise the PCR output voltage has low-order subharmonics whose suppression requires a bulky passive filter. The digital PLVC has a fast dynamic characteristics as an inner control loop of the PCR. To suppress further the output ripple, an active filter using a transformer is introduced and its design is described through the frequency domain analysis. An optimal integral, proportional and measurable variable feedback (IPM) controller is designed using the time-weighted performance index based on the time domain analysis. The design method based on the time-weighted performance index gives better response characteristics than that based on the conventional performance index. It is also shown via experimental results that the proposed scheme gives better response characteristics than that based on the conventional performance index. It is also shown via experimental results that the proposed scheme gives good dynamic and static performances.

• The Journal of Asian Finance, Economics and Business
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• 제8권8호
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• pp.487-496
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• 2021

This study examines the environmental performance of firms in Vietnam and its determinants. The contribution of the paper is on both theoretical and empirical aspects. On the theoretical matter, the research proposes a new index measuring environmental management at the firm level, namely the Environmental Management Index with a clear illustration for the case of Vietnam. On the empirical matter, the study points out and estimates determinants of the corporate environmental performance of Vietnamese firms measured by the newly proposed index. Due to data availability and the impossibility of getting more updated data, the empirical analysis covers only the period from 2004-2009. However, findings are still meaningful because, on the one hand, it provides some evidence for Vietnamese policymakers; on the other hand, with the robust methodology proposed, when more recent data are available, researchers can easily replicate the estimation for more insights. Empirical results show that factors having positive impacts on the environmental performance of Vietnamese firms are profit, capital stock, and interestingly public pressure proxied by the population of the province where the firm is located. Firm ownership does also matter in explaining the corporate environmental performance of Vietnam.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2020년도 전력전자학술대회
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• pp.106-108
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• 2020

This paper introduces a new pulse-width modulation (PWM) method to reduce common-mode voltages (CMVs) and compare its performance with other reduced CMV-PWM (RCMV-PWM) methods. To avoid the use of zero-vectors which cause high CMV peaks, the introduced method splits every reference vector into two vectors such that the peak-to-peak magnitude of CMV is reduced by one-third of conventional space-vector PWM (SVPWM). The performance of RCMV-PWMs altered by the modulation index are analyzed with simulation results.

• 한국정밀공학회지
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• 제27권2호
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• pp.86-93
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• 2010

The tilting index table has attached to CNC machining center with 3axes, it can be improvement of its performance and its machining efficiency. The tilting index table is a key unit in order to manufacture some non-rotational and 3-dimensional parts, using the conventional machining center. In this study, structural analysis is carried out by FEM simulation using the commercial software ANSYS Workbench 11 to develop tilting index table using direct drive motor. The shape of the tilting index table obtained from the optimization was analyzed and compared with the initial model. Also, the initial model was modified based on the optimization model and the result was verified to have the acceptable improvement.

• Journal of the Korean Physical Society
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• 제73권10호
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• pp.1589-1595
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• 2018

Similarity index measures the topological proximity of node pairs in a complex network. Numerous similarity indices have been defined and investigated, but the dependency of structure on the performance of similarity indices has not been sufficiently investigated. In this study, we investigated the relationship between the performance of similarity indices and structural properties of a network by employing a two-state random network. A node in a two-state network has binary types that are initially given, and a connection probability is determined from the state of the node pair. The performances of similarity indices are affected by the number of links and the ratio of intra-connections to inter-connections. Similarity indices have different characteristics depending on their type. Local indices perform well in small-size networks and do not depend on whether the structure is intra-dominant or inter-dominant. In contrast, global indices perform better in large-size networks, and some such indices do not perform well in an inter-dominant structure. We also found that link prediction performance and the performance of similarity are correlated in both model networks and empirical networks. This relationship implies that link prediction performance can be used as an approximation for the performance of the similarity index when information about node type is unavailable. This relationship may help to find the appropriate index for given networks.