• Journal of Mechanical Science and Technology
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• 제19권9호
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• pp.1801-1810
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• 2005

The effect of longitudinal thin rectangular riblets aligned with the flow direction on turbulent channel flow has been investigated using direct numerical simulation. The thin riblets have been modeled using the immersed boundary method (IBM) where the velocities at only one set of vertical nodes at the riblets positions are enforced to be zeros. Different spacings, ranging between 11 and 43 wall units, have been simulated aiming at getting the optimum spacing corresponding to the maximum drag reduction while keeping the height/spacing ratio at 0.5. Reynolds number based on the friction velocity ${\mu}_\tau$ and the channel half depth $\delta$ is set to 150. The flow is driven by adjusted pressure gradient so that the mass flow rate is kept constant in all the simulations. This study shows similar trend of the drag ratio to that of the experiments at the different spacings. Also, this research provides an optimum spacing of around 17 wall units leading to maximum drag reduction as experimental data. Explanation of drag increasing/decreasing mechanism is highlighted.

• 의학교육논단
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• 제20권3호
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• pp.156-163
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• 2018

The purpose of this study was to investigate the effects of academic resilience and interpersonal competence on the happiness of nursing students. A descriptive design was used to study 158 nursing students in nursing school through convenience sampling. IBM SPSS ver. 23.0 (IBM Corp., Armonk, NY, USA) was used to analyze data for descriptive statistics, t-test, analysis of variance, Tukey post hoc test, Pearson's correlations, and multiple regressions. The results showed that the level of nursing students' happiness was lower than that of college students in other majors, but academic resilience and interpersonal competence among nursing students were relatively high. Nursing students' happiness was positively correlated with academic resilience and interpersonal competence. The factors affecting happiness were academic resilience (${\beta}=0.459$, p<0.001), satisfaction with major (${\beta}=0.272$, p=0.006), perceived subjective health status (${\beta}=0.223$, p=0.013), and interpersonal competence (${\beta}=0.185$, p=0.003). Explained variance for happiness was 56.4%, and academic resilience was the most influential factor in the happiness of nursing students. Nursing students are caring human beings and should be able to pursue a happy life; therefore, it is necessary to improve satisfaction levels with the nursing major, guide students to excel in their academic achievement, prepare health education programs, and design curriculum that inspires confidence in interpersonal relationships.

• 한국진공학회지
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• 제12권S1호
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• pp.7-9
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• 2003

Solid-state reactions in Ni/Si multilayered films (MLF) with an overall stoichiometry of $Ni_2Si$, NiSi and $NiSi_2$, induced by ion-beam mixing (IBM) and thermal annealing, were studied by using spectroscopic ellipsometry and magneto-optical spectroscopy as well as x-ray diffraction (XRD). The mixing was performed with Ar+ ions of an energy of 80 keV and a dose of $1.5 x\times10^{16}$ $Ar^+$/$\textrm{cm}^2$. It was shown that the IBM induces structural changes in the Ni/Si MLF, which cannot be detected by XRD but are confidently recognized by the optical method. A thermal annealing at 673 K of the Ni/Si MLF with an overall stoichiometry of NiSi and $NiSi_2$ causes formation of the first η -NiSi phase. The first trace for $NiSi_2$ phase on the background of NiSi one was detected by XRD after an annealing at 1073 K while, according to the optical results, $NiSi_2$ turns out be the dominant phase for the annealed Ni/Si MLF with an overall stoichiometry of $NiSi_2$.

• The Journal of the Acoustical Society of Korea
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• 제13권1E호
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• pp.89-95
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• 1994

본 논문에서는 화자독립으로 100단어를 인식할 수 있는 실시간 음성인식 다이얼링 시스템의 개발에 대하여 기술하였다. 이 시스템에서 음성인식 알고리즘은 전화선 인터페이스를 갖춘 DSP 보드상에 구현되었으며, IBM PC AT/486 상에서 작동된다. DSP 보드에서는 단어의 시작점이 검출된 후에 특징추출, 벡터양자화 그리고 끝점검출 과정이 실시간으로 10 msec의 프레임 구간마다 수행된다. 또한, 본 시스템에서는 인식시간과 기억용량을 줄이기 위해 VQ 코드북의 크기와 끝점검출 과정을 최적화하였다. 본 실시간 음성인식 다이얼링 시스템은 데모 시스템으로 구현되어 대전엑스포‘93에서 한국이동통신의 MOBILAB 내에 전시되었다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2001년도 춘계종합학술대회
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• pp.414-417
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• 2001

본 논문은 버스회사의 각 버스를 자동인식하고 그 버스에 주입된 주유량을 자동 계측하여 본사 메인 컴퓨터로 LAN을 통해 데이터를 전송함으로써 본사에서 일괄 처리한 수 있는 시스템으로 버스 자동인식장치, IBM-PC, 주유기 제어 시스템 및 처리 프로그램으로 크게 나뉘어진다. 본 시스템 도입으로 버스회사의 모든 차량 주유상태를 통합관리 할 수 있어 각 버스별, 노선별, 전체의 기름소모량을 일률적으로 화인 관리할 수 있다. 이렇게 함으로써 운전자의 운전습관, 노후정도 및 정비 스케줄의 판단정보로 활용할 수 있고, 경영혁신과 월가분석을 통한 에너지 절감효과가 있다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2013년도 춘계학술대회
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• pp.690-692
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• 2013

빅데이터 시대를 맞이하여 주목 받는 기술 중 하나인 클라우드는 인터넷 기반인 컴퓨팅 기술이다. 클라우드는 여러 대의 물리 서버를 하나의 가상 서버로 통합하여 필요할 때 마다 인터넷 상에서 가져와 사용하는 기술이며 현재 미국 IT 선두 기업인 아마존, IBM, 구글, MS와 국내 기업인 삼성, SK, KT, NHN 같은 대기업들이 클라우드에 투자하여 현재 상용화하고 있으며 앞으로 클라우드 시장은 국내외로 계속 성장할 것이다. 클라우드 도입에 주요한 이유는 운영 비용의 절감이며 가장 문제점으로 보이는 것은 개인 정보 유출이다. 본 논문에서는 클라우드 보안 기술과 취약점을 분석하고 보안을 향상시키는 방법을 제안한다.

• 한국통신학회논문지
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• 제14권6호
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• pp.590-603
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• 1989

본 논문에서는 단축 Hamming 부호의 일종이며 오류검출용 검사비트 수가 16인 CRC-CCITT 부호화 원시다항식 CRC 부호에 대한 성능 분석을 위하여 필수적으로 요구되는 중분포(weight distribution)를 구하는 기법과 오류검출 성능을 분석하는 기법을 제안하였고, 두 CRC(cyclic redundant code)부호를 CCITT에서 광대역 ISDN의 가입자망 인터페이스의 전송방식으로 권고된 ATM(asynchronous transfer mode)전송방식의 오류검출을 부호로 적용하여 현재 고려되고 있는 cell 크기에 대한 증분포 및 미검출오류확률(undetected error probability)을 구한 후, 두 오류검출부호의 성능을 비교/분석 하였다. 분석 결과, 현재 고려되는 셀 크기에 대해 CRC-CCITT 부호의 성능이 원시다항식 CRC 부호의 성능보다 더 우수함이 입증되었다 .이를 위한 모든 계산을 IBM PC/AT를 이용하여 수행하였다. 한편 본 논문에서 제안한 단축 Hamming 부호의 성능 분석 기법은 지금까지 디지틀 통신시스템에 적용되고 있는 또는 적용예정인 CRC 오류검출 부호의 성능 분석에 이용될 수 있다.

• 한국IT서비스학회지
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• 제9권1호
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• pp.141-156
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• 2010

Service industry has become the integral part of economy. And the activation of industry requires a scientific and systematic approach. As one of these kinds of efforts, IBM presented a service model which consisted of strategies, processes, technology, manpower and so on through Service Science. And IBM raised the needs of considering the main issue and methodology of service model's scientific approach. On that account, this study worked out factorial definitions and measurable items by the four components of service model presented by Service Science in order for it to be measured through studies on related literature and interviews of specialists. In order to prepare an opportunity of categorizing the conception of the service model of which character was strongly intangible and of systematically approaching to it, the investigator examined related literature and applied it QFD methodology. Through this kind of redefinition, the investigator concretely conceptualized the service model which was standstill at the level of theoretical approach so far and presented guidelines with which researchers could classify it more concretely. In addition, the investigator tried to present a systematic frame which could be applied to business by working-level officials or decision-makers. Therefore, the investigator expects that study findings will be used as references for the design or implementation of service-oriented business model.

• 한국표면공학회지
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• 제29권6호
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• pp.824-828
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• 1996

Co-based alloy thin films ddeposited by fcing targets sputtering(FTS) were investigated for use in high-density magnetic recording media to determine how their magnetic properties are dependent on the sputtering conditions, and thus to find appropriate parameters that allow the sputtering and thin films to meet the specificiations for magnetic properties. FTS can discharge at lower working gas pressure than other sputtering methods such as dcmagnetron sputteing because the plasma is sufficiently confined by a magnetic field applied perpendicular to both of the target planes, which results in plasma-free substrates. Co-Cr-Ta films were deposited by FTS on glass and silicon substrates at substrate temperature between room temperature and $350^{\circ}C$, and at argon gas pressure between 0.1 and 10mTorr. The films were also deposited on polyimide tapes at substrate temperature of $130^{\circ}C$ and argon gas pressure of 1 mTorr. The effective advantages of Ta as an additional element were investigated, using the same films on the tapes. As a result of the experiment, it was found that better magnetic properties were obtained in the ranges of higher temperature and lower argon gas pressure with background pressure in thr range of $1.5 \times 10^{-6}$ Torr. Ta addition at 2 to 4 atomic percent almost havled the Co-Cr grain sizes, indicating that Ta addition at an appropriate atomic percent is effective for improving the microstructure and characteristics of Co-Cr films.

• 유통과학연구
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• 제15권11호
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• pp.5-19
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• 2017

Purpose - According to the research findings, it proposes corresponding market promotion schemes, for Alipay, WeChat wallet and even other payment service providers and mobile internet companies to understand the factors which promote or hinder users' acceptance of mobile payment. Research design, data, and methodology - Statistic analysis of data and social science statistical software of IBM Statistics 23.0 and IBM SPSS AMOS 23.0 were adopted for all the data researched. Results - The technical features of the third party mobile payment and the task characteristics of users have positive influence on the matching degree between task and technology, and the matching degree between task and technology of the third party mobile payment has positive influence on the performance expectancy, effort expectancy and usage intention. The social influence, facilitating condition, price value and enjoyment motivation have significant and positive influence on users' intention of mobile payment adoption. The perceive security of the mobile fingerprint payment of users has positive influence on users' intention of usage. Conclusions - This research has the main contribution on the analysis on the key factors with influence on the third party mobile payment usage by utilizing the integrated model of UTAUT2 and TTF.