• Tribology and Lubricants
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• 제36권5호
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• pp.279-289
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• 2020

In this paper, a method is proposed for establishing an approximate prediction model of rotor-dynamics through modal testing. In particular, the proposed method is applicable to systems that cannot be established according to conventional methods owing to the absence of information regarding the dimensions and material of the rotor-bearing system. The proposed method is demonstrated by employing a motor dynamometer driven by a 1 MW class induction motor without dimension and material information. The proposed method comprises a total of seven steps, wherein an initial model is established by incorporating approximate dimensions and material information, and the model is improved on the basis of the natural frequency characteristics of the system. During model improvement, the modification factor is introduced for adjusting the elastic modulus and shear modulus of the system. Analysis of critical speed and imbalance response indicates that the separation margin is 67% and the maximum vibration amplitude is less than the amplitude limit of 0.032 mm under the API 611 standard, which means that the motor dynamometer can stably operate at a rated speed of 1800 rpm. Hence, the obtained results validate the feasibility of the proposed method. Furthermore, for broad usage, it is necessary to accordingly apply and validate the proposed method for various rotor-bearing systems.

• 한국산업정보학회논문지
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• 제13권3호
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• pp.100-109
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• 2008

1990년대와 2000년대 초 현재까지 ERP시스템 구축 시장은 괄목할 만한 성장을 계속하여 왔다. 2009년에 ERP 시장은 세계적으로 약 65조원 규모까지 성장할 것으로 예견되고 있다. 거의 모든 기업이 이러한 ERP 시스템에 의하여 일상의 사업 거래 업무를 처리하게 될 것이라 해도 과언이 아니다. 그러나 ERP 구축 프로젝트는 많은 시간, 광범위한 관련 범위, 그리고 큰 예산 비용을 요구하는 하나의 방대하고 전략적이며 복잡한 프로젝트이다. 이것은 기업에게 있어 ERP 시스템 구축은 반드시 성공하여야 할 프로젝트임을 의미하며 ERP 시스템 구축 성공요인이 무엇인가에 대한 이해가 기업 경영자들에게 매우 중요함을 뜻한다. 본 연구는 먼저 ERP분야의 선행연구들 특히 ERP시스템 구축 성공요인 연구 결과들을 살펴봄으로써 최근에 강조되고 있는 중요 성공요인에는 어떠한 것이 있는지 살펴본 다음에 본 설문조사 실증연구 결과를 기존의 연구와 비교적으로 소개하면서 ERP 시스템을 구축 사용하고 있는 기업 경영자들에게 유용한 관리 지침을 제공하고자 한다.

• Progress in Superconductivity
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• 제14권1호
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• pp.30-33
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• 2012

We have grown $MgB_2$ superconducting thin films on the SiC buffer layers by means of hybrid physical-chemical vapor deposition (HPCVD) technique. Prior to that, SiC was first deposited on $Al_2O_3$ substrates at various temperatures from room temperature to $600^{\circ}C$ by using the pulsed laser deposition (PLD) method in a vacuum atmosphere of ${\sim}10^{-6}$ Torr pressure. All samples showed a high transition temperature of ~40 K. The grain boundaries of $MgB_2$ samples with SiC layer are greater in amount, compare to that of the pure $MgB_2$ samples. $MgB_2$ with SiC buffer layer samples show interesting change in the critical current density ($J_c$) values. Generally, at both 5 K and 20 K measurements, at lower magnetic field, all $MgB_2$ films deposited on SiC buffer layers have low $J_c$ values, but when they reach higher magnetic fields of nearly 3.5 Tesla, $J_c$ values are enhanced. $MgB_2$ film with SiC grown at $600^{\circ}C$ has the highest $J_c$ enhancement at higher magnetic fields, while all SiC buffer layer samples exhibit higher $J_c$ values than that of the pure $MgB_2$ films. A change in the grain boundary morphologies of $MgB_2$ films due to SiC buffer layer seems to be responsible for $J_c$ enhancements at high magnetic fields.

• 한국콘텐츠학회논문지
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• 제17권5호
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• pp.529-539
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• 2017

본 연구는 이공계 대학생들의 커뮤니케이션 역량을 범주화하여 분석하고 그 결과를 토대로 향후 이공계 대학생의 커뮤니케이션 역량 향상을 위한 교육 콘텐츠 개발 방안을 제시하는데 목적이 있다. 이 연구에서 이공계 대학생의 커뮤니케이션 역량은 비판적 사고력, 과학적 소통력, 미디어리터러시 세 영역으로 범주화 하였다. 또한 커뮤니케이션 역량을 향상시키기 위한 수단으로써 이공계 글쓰기에 대한 경험과 인식을 조사하였다. 연구결과, 이공계 대학생의 커뮤니케이션 역량은 전반적으로 향상될 필요가 있는 것으로 나타났다. 또한 실습중심의 비판적 사고력을 향상시킬 수 있는 글쓰기 프로그램에 대한 요구도가 높게 나타났다. 교육 콘텐츠로는 플립러닝 등 스마트교육기반 프로그램, E-커뮤니티, 액션러닝 기반 문제해결력 향상 프로그램, 협동학습 프로그램, 성찰 저널 및 포트폴리오, 협업형 글쓰기 프로그램 등을 제안하였다. 이 연구의 결과는 이공계 학생을 대상으로 한 커뮤니케이션 역량중심 교육과정 설계와 현장에서의 구체적인 적용과 실천 지침을 제공하는데 기초자료로 활용될 수 있을 것이다.

• Structural Engineering and Mechanics
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• 제11권1호
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• pp.35-48
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• 2001

The objective of this study is to investigate the stability behavior of steel cable-stayed bridges by comparing the buckling loads obtained by means of finite element methods with eigen-solver. In recent days, cable-stayed bridges dramatically attract engineers' attention due to their structural characteristics and aesthetics. They require a number of design parameters and present a high degree of static indetermination, especially for long span bridges. Cable-stayed bridges exhibit several nonlinear behaviors concurrently under normal design loads due to the individual nonlinearity of substructures such as the pylons, stay cables, and bridge deck, and their interactions. The geometric nonlinearities arise mainly from large displacements of cables. Strong axial and lateral forces acting on the bridge deck and pylons cause structural nonlinear behaviors. The interaction is among the substructures. In this paper, a typical three-span steel cable-stayed bridge with a variety of design parameters has been investigated. The numerical results indicate that the design parameters such as the ratio of $L_1/L$ and $I_p/I_b$ are important for the structural behavior, where $L_1$ is the main span length, L is the total span length of the bridge, $I_p$ is the moment of inertia of the pylon, and $I_b$ is the moment of inertia of the bridge deck. When the ratio $I_p/I_b$ increases, the critical load decreases due to the lack of interaction among substructures. Cable arrangements and the height of pylon are another important factors for this type of bridge in buckling analysis. According to numerical results, the bridges supported by a pylon with harp-type cable arrangement have higher critical loads than the bridges supported by a pylon with fan-type cable arrangement. On contrary, the shape of the pylon does not significantly affect the critical load of this type of bridge. All numerical results have been non-dimensionalized and presented in both tabular and graphical forms.

• 중환자간호학회지
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• 제14권2호
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• pp.1-11
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• 2021

Purpose : The aim of this study was to propose appropriate nurse staffing of adult intensive care units considering patients' nursing care needs according to the Workload Management System for Critical Care Nurses (WMSCN). Methods : In a cross-sectional survey conducted in September 2017, 1,786 patients' WMSCN scores, surveys from 2,145 nurses, and administrative data from 118 units in 41 hospitals were analyzed. The means (standard deviations) of the aforementioned scores and nursing hours per patient day were presented. Nurse-to-patient ratios and nurse-to bed ratios for staffing to meet patients' nursing care needs were calculated. Results : The mean WMSCN scores were 109.50±17.17 in tertiary hospitals and 96.38±19.26 in general hospitals. Nursing hours per patient day were 12.47±2.80 in tertiary hospitals and 11.01±2.45 in general hospitals. Nursing hours per patient day correlated with WMSCN scores. Nurse-to-bed ratios required for the provision of ICU nursing care ranged from 1: 0.36 to 1: 0.48. Conclusion : Our findings provide evidence that current ICU nurse staffing is insufficient for meeting patients' nursing care needs. We suggest adjusting the legal standards for adequate nurse staffing considering these needs.

• 한국콘텐츠학회논문지
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• 제22권9호
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• pp.712-726
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• 2022

이 연구는 신문의 뉴스 기사가 '마약 중독'에 대해 어떤 담론을 생산·유통하는지 알아보고, 그 담론의 지형과 의미를 밝히는데 목적이 있다. 이를 위해 국내 4개 일간지 신문의 뉴스기사를 대상으로 '마약', '마약 중독'을 키워드로 검색하여 자료를 수집하였다. 페어클로(Norman Fairclough)의 비판적 담론분석 방법을 활용하여 분석한 결과, 첫째, 텍스트 분석에서 마약 중독은 '범죄-처벌' 담론이 지배적이었다. 마약중독은 사회악이자 성범죄, 아동범죄, 폭력과 같은 중범죄이므로 엄격히 처벌해야 한다는 것이다. 둘째, 담론실천 분석에서 마약 중독은 치료가 필요한 '질병', 즉 정신질환이므로 국가에 의한 체계적 관리가 필요하다. 셋째, 사회문화적 실천 분석에서 마약 중독은 경제적 이익을 목적으로 한 돈벌이 수단이자, 정치권력의 부패와 관련이 있으며, 마약범죄가 국가의 근간을 위협하지 못하도록 강력히 통제해야 할 대상이다. 문화적으로 마약 중독은 쾌락 추구의 동기에서 비롯되며, 도덕적 타락의 결과이다. 이러한 분석을 통해 마약 중독의 지배 담론인 '범죄-처벌' 담론의 한계를 지적하고, '질병-치료' 담론으로의 전환과 치료·재활 중심의 약물정책을 대안으로 제시하였다.

• 한국인터넷방송통신학회논문지
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• 제12권1호
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• pp.141-150
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• 2012

본 논문은 프로젝트 일정을 계획하고 관리하는 PERT/GANTT 차트를 쉽게 그릴 수 있는 임계경로 탐색 알고리즘을 제안하였다. 프로젝트 일정을 결정하는 임계경로를 계산하기 위해 일반적으로 CPM (Critical Path Method)이 적용되고 있다. 그러나 CPM은 프로젝트 수행 활동들의 수행 기간과 상호 의존 관계에 따라 초기에 작성된 네트워크 다이어그램에 대해 임계경로를 계산하는데 5 단계를 수행하며, $T_E$ (The Earliest Time)을 계산하는 노드 (활동)들의 순서를 결정하는 방법을 제시하지 않아 특정 노드의 $T_E$를 정확히 계산하지 못할 수도 있다. 또한, CPM으로 얻은 네트워크 다이어그램의 활동들의 수행 순서가 시각적으로 명확히 표현할 수 없어 Lucko는 9 단계를 거치는 알고리즘을 제안하였다. 반면에, 제안된 알고리즘은 먼저, 초기에 작성된 네트워크 다이어그램에 대해 너비우선 탐색으로 노드들을 레벨로 재배치하여 수행 순서를 사전에 결정한다. 다음으로, 각 레벨에 속한 노드들을 임의로 선택하여 $T_E$를 계산하는 단계만을 거쳐 임계경로를 즉시 결정한다. 마지막으로, 각 레벨에서 임계경로에 속한 노드들의 $T_E$를 기준으로 임계경로에 속하지 않은 노드들의 $T_E$에 따라 약간의 이동으로 프로젝트 활동들의 수행 순서를 시각적으로 명확히 표현하도록 하였다. 제안된 알고리즘은 10개의 실제 프로젝트 데이터에 대해 적용성을 검증하였다. 제안된 알고리즘은 모든 프로젝트에서 임계경로를 구할 수 있었으며, 활동들의 수행 순서를 시각적으로 명확히 표현하였다. 또한, 제안된 알고리즘은 CPM의 5단계를 1단계로 단축시키는 장점과 더불어 활동들의 수행순서를 명확히 표현하기 위한 Lucko의 9 단계 수행 과정을 2단계로 간단히 하였으며, PERT/GANTT 차트로 즉시 전환시킬 수 있는 장점도 갖고 있다.

• 유통과학연구
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• 제16권12호
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• pp.81-93
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• 2018

Purpose - The purpose of this study was to propose a specific and empirical continuous transaction strategy through service quality of improvement to small and medium Korean companies whose main business is B2B distribution and sale of general-purpose SW. Research design, data, and methodology - The research procedure is largely divided into two phases. In the first phase, the service quality, the customer satisfaction, and the continuous transaction research hypothesis and the verification are carried out. Experimental data were collected from 450 companies, CEO companies of SMEs innovation institutes, and 510 companies from medium and large enterprises. From September 15 to October 5, 2015, 215 questionnaires were used. And research hypothesis and test were conducted by SPSS SW Ver. 20. Results - The results of the study confirm that service quality has a positive effect on customer satisfaction and continuous transaction: as the detailed items for improving the service quality, 'responsiveness', 'assurance' and 'empathy' have been adopted. Therefore, there are critical factors of a company's survival through continuous transaction. Conclusions - Through this study, we confirmed that the survival of small businesses require continuous improvement in service quality. Among the factors improving service quality, empathy means service satisfaction of customers; so, it is necessary to continuously improve it by evaluating customer satisfaction. Responsiveness means rapid response to customer needs and reliability; it is necessary to enhance customer responsiveness by continuous job training and service training. Finally, assurance is the same as sales product or after service. This means that it is necessary to not only issue the "supply contract," but also improve the reliability of the sales product by securing the competence of the consulting professional. However, because the service quality measurement factors selected in this study are the measurement factors that are mainly applied to large companies or those in the service industries, it is important to consider the type of sales of software distribution companies.

• 지식경영연구
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• 제6권1호
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• pp.105-122
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• 2005

The LG Electronics case shows the process whereby an organization evolves as a learning organization through the integration of e-learning and knowledge management. In other words, it shows the process whereby e-learning is recognized as an important means of solving a problem concerning actual worksite operations, as it became one of the daily activities in the organization. In terms of organizational learning, this process points to the fact that e-learning is emerging as the fastest and most effective means of transferring the internally shared value of a company. Recently, advanced corporations and organizations have been endeavoring to boost their internal and external customer satisfaction and customer loyalty, paving the way for changes in their organizational cultures, and establishing learning organizations through e-learning. Therefore, from an advanced viewpoint, e-learning within a company is not a simple system of transferring educational contents, but is a knowledge portal concept connected with knowledge management. To achieve this end, the organization is required to undergo changes that is, it should make the acquisition of learning possible through e-learning and a knowledge management system (KMS) in order to improve corporate performance. Since LG Electronics is utilizing e-learning as a strategic means to change the paradigm of corporate education, and, in particular, is attempting to integrate this with knowledge management, insights that will facilitate the understanding of the core success factors in and challenges to the integration of knowledge management and e-learning can be obtained through this case.