• 한국정보시스템학회지:정보시스템연구
• /
• 제20권2호
• /
• pp.155-176
• /
• 2011

The use of mobile office systems has been expanded due to the smartphones' rapid diffusion in Korea, and it has brought a new work environment that is different from traditional working patterns. In this study, the unique attributes of mobile office systems, such as ubiquity, usefulness, complexity, and insecurity, are examined along with the impact of these attributes on work overload and job stress. Based on transaction-based model of job stress, organizational support was applied as a stress inhibitor and also the moderator between work overload and job stress. The findings of this study show that ubiquity increases usefulness of mobile office systems; complexity increases both work overload and job stress; and insecurity increases job stress. Surprisingly, usefulness increases job stress, which means employees who perceive the efficiency of mobile office systems higher may feel more job stress. Organizational support for mobile office systems significantly shows the moderating effect, but no direct mitigating effect on job stress. The theoretical and practical implications in order to mitigate the side effects of mobile office systems based on the research findings are thoroughly discussed.

• 한국정보시스템학회지:정보시스템연구
• /
• 제28권4호
• /
• pp.377-401
• /
• 2019

Purpose The purpose of this study is to investigate the effects of learning expectation and perceived knowledge sharing on user satisfaction and IS continuance in the Korean Army which is currently using the Regiments' Information System to help their Integrated Administration Management. Based on both the Information System(IS) Continuance Model and IS Success Model, this study also examine the role of system quality on user satisfaction. We develop a research model(structural equation model) and its hypotheses that learning expectation, perceived knowledge sharing, and system quality increase users' satisfaction, which leads to IS continuance. The effect of learning expectation on perceived knowledge sharing is also hypothesized. Design/methodology/approach Online Survey using e-mails was administered to test our research model and associated hypotheses. Among the 360 e-mail letters including our survey questionnaire, 285 responses were collected via e-mails. Meaningful 225 cases were analyzed for our study. SPSS Statistics 24.0 and SmartPLS 3.0 were used to analyze both measuremant test and hyotheses test by using the data set. Findings Survey results show that learning expectation(confirmation variable), learning expectation, perceived knowledge sharing(a perceived usefulness variable), and system quality(a system characteristic) each increases user satisfaction, which leads to IS continuance, under the control of the effect of habit to use information systems. Learning expectation also has a positive influence on perceived knowledge sharing. Theoretical and practical implications are presented.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2009년도 춘계 학술대회 제21권1호
• /
• pp.157-158
• /
• 2009

본 연구는 휨-압축을 받는 교각 기둥 부재의 구조 요소별 철근과 콘트리트 강도 및 하중조건에 따른 구조거동 특성을 분석하고, 교각 기둥에 대한 매개변수 해석(Parameter Study)을 실시하여 콘크리트 강도별 및 높이별 기둥의 최적단면 및 공사비를 검토하였다. 검토결과, 기존의 27MPa 콘크리트 대신 40MPa 고강도 콘크리트를 적용할 경우, 기둥 단면이 축소되고 공사비도 평균 8%정도 감소되어 교각의 미관 및 경제성 측면에서 개선효과가 있음을 알 수 있었다. 또한 음성${\sim}$충주간 고속도로 건설공사내의 신효교 교각에 대하여 본 연구결과를 적용하여 실용적 효과성을 검증하였다.

• 한국태양에너지학회 논문집
• /
• 제30권5호
• /
• pp.11-16
• /
• 2010

Methane hydrate is crystalline ice-like compounds which formed methane gas enters within water molecules composed cavity and each other from physically-bond at specially temperature and pressure condition. $1m^3$ of methane hydrate can be decomposed into the maximum of $216m^3$ of methane gas under standard condition. If these characteristics of hydrate are utilized in the opposite sense, natural gas can be fixed into water in the form of a hydrate solid. Therefore the use of hydrate is considered to be a great way to transport and store natural gas in large quantity. However, when methane hydrate is formed artificially, the amount of gas that is consumed is relatively low, due to the slow reaction rate between water and methane gas. Therefore for practical purposes in the application, the present investigation focuses on increasing the amount of gas consumed by adding chemically oxidized OMWCNTs to pure water. The results show that when 0.003 wt% of oxidation multi-walled carbon nanotubes was added to pure water, the amount of gas consumed was almost four times more than that of pure water indicating its effect in hydrate formation and the hydrate formation time decreased at alow subcooling temperature.

• Communications for Statistical Applications and Methods
• /
• 제19권5호
• /
• pp.685-696
• /
• 2012

These days the interest of quality leads to the necessity of control charts for monitoring the process in various fields of practical applications. The $\overline{X}$ chart is one of the most widely used tools for quality control that also performs well under the normality of quality characteristics. However, quality characteristics tend to have nonnormal properties in real applications. Numerous recent studies have tried to find and explore the performance of $\overline{X}$ chart due to non-normality; however previous studies numerically examined the effects of non-normality and did not provide any theoretical justification. Moreover, numerical studies are restricted to specific type of distributions such as Burr or gamma distribution that are known to be flexible but can hardly replace other general distributions. In this paper, we approximate the false alarm rate(FAR) of the $\overline{X}$ chart using the Edgeworth expansion up to 1/n-order with the fourth cumulant. This allows us to examine the theoretical effects of nonnormality, as measured by the skewness and kurtosis, on $\overline{X}$ chart. In addition, we investigate the effect of skewness and kurtosis on $\overline{X}$ chart in numerical studies. We use a skewed-normal distribution with a skew parameter to comprehensively investigate the effect of skewness.

• 한국해양공학회지
• /
• 제10권4호
• /
• pp.75-83
• /
• 1996

Polymeric composites can be subjected to a wide variety of environmemtal conditions in practical use. One of most important conditions to be considered in the stuctural design using such materials is the miisture envirnment. Thus the moisture effect on interlaminar fracture toughness $G_IC$ and $G_IIC$ of CFRP(carbon fiber reinforced plastic) composed of carbon fibers and epoxy resin is studied in this paper. Specimens were first processed in 25, 50, $80^{\circ}C$ flesh water and $25^{\circ}C$ sea water for various periods of time. After that, the water absorption and fracture toughness tests were performed under laboratory atmosphere. As result, the specimen processed in $80^{\circ}C$ flesh water indicates the highest misture absorbing capability, the second in $50^{\circ}C$ flesh water, the third in $25^{\circ}C$ sea water, and the specimen in $25^{\circ}C$ flesh water does the lowest. The interlaminar fracture toughness $G_IC$ increases, approaches to the maximum, and decreases as the immersion time increases. In case of interlaminar $G_IIC$, the value of the specimen processed in $80^{\circ}C$ flesh water turns out to be higher than others. In addition, the scanning electron micrographs(SEM) of fracture surfaces were also examined in order to explain the mechanism of fracture.

• 한국해양공학회지
• /
• 제24권2호
• /
• pp.67-73
• /
• 2010

A simplified finite element analysis has been used to predict the weld-induced deformation to bead-on-plate welding of steel plates having curvatures in the welding direction. In this study, the equivalent loading method based on inherent strain was used to investigate the effect of longitudinal curvature on the weld-induced deformation of curved plates. Equivalent loads were derived from the inherent strain distribution around the weld line, and the loads were used for linear finite element analyses. These kinds of numerical simulations can, of course, be performed by using the rigorous thermalelastic-plastic analysis method. This approach is not, however, practical for use in weld-induced deformation analysis of large and complex structures, such as ship structures, in view of computing time and cost. The present equivalent load approach has been applied to several plate models having curvatures in the welding direction, and the results are compared with those obtained by thermal-elastic-plastic analysis and also with those obtained by the other simplified method found in reference. As far as the present results are concerned, the weld-induced deformation of curved plates can be accurately predicted by the method presented in this paper.

• 한국전자통신학회논문지
• /
• 제10권7호
• /
• pp.775-780
• /
• 2015

초전도 현상은 절대온도 부근에서 전기적 저항이 사라지고 자기부양 효과를 보이는 등의 장점 때문에 다양한 분야에서 적용이 시도되고 있지만 초전도 임계온도를 실현하기 위한 어려움 때문에 실용화에 많은 어려움을 겪어 왔다. 하지만 최근 $30^{\circ}K$ 이상에서 초전도 현상을 보이는 고온 초전도체가 발견됨으로서 다양한 분야에 대한 적용연구가 시도되고 있다. 따라서 본 논문에서는 최근 각광받고 있는 고온 초전도체의 전력계통 적용 사례들은 조사, 분석하여 그 가능성과 문제점들을 살펴보고자 한다.

• 조명전기설비학회논문지
• /
• 제23권5호
• /
• pp.66-71
• /
• 2009

태양광 발전은 일사량이 높을수록 발전량이 증가된다. 그러나 일사량이 높아짐에 따라 셀의 온도도 같이 증가해 발전 효율은 감소하게 된다. 냉각시스템의 설치는 이러한 문제점을 해결하기 위한 적절한 방법이 될 수 있으나 냉각시스템 설치 후 태양광 발전량의 증가량, 냉각시스템의 설치비용, 냉각시스템의 유지 보수비용 등 실용화에 필요한 내용은 논의되고 있지 않다. 따라서 본 논문에서는 냉각시스템의 효과 및 상용화 가능성에 대해 기술하였다. 실험결과 냉각시스템 설치 후, 연평균 약 5.76[%]의 발전량 증가를 기대할 수 있다.

• 대한간호학회지
• /
• 제15권2호
• /
• pp.16-24
• /
• 1985

This study considered the problem of whether the method of Lamaze education changes maternal attitudes toward childrearing, material-infant interaction and is feasible for Korean culture in nineteen mother. infant dyads. Among those mothers, nine were assigned experimental group who received Lamaze education at the period of 7th and 8th month of gestation, and ten were assigned control group who received obstetric routine care. Maternal attitudes were assessed with selected items from Cohler's Maternal Atttiude Scale. Maternal Play Interaction Scale was used during play session to evaluate maternal sensitivity, infant response and mother-infant dyadic synchrony. There were no significant differences not only between the two groups, but also between the period of pre-lamaze education and post-delivery on the Cohler's maternal attitude scale. Experimental mothers and babies scored significantly higher on maternal sensitivity and infant response. But no differences in mother-infant, dyadic synchrony were found. This findings mean that the effect of the lamaza education on the maternal attitudinal change related to be needed the change of cognitive structure is delayed while the effect of that on the maternal infant behavioral response showed immediatly. Modification of Lamaze method is necessary for practical use in our sociocultural system.