• 한국노년학
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• 제31권1호
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• pp.1-14
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• 2011

본 연구는 노인의 주관적 건강상태, 경제수준, 우울감, 사회적지지가 주관적 삶의 질에 미치는 영향을 죽음불안이 매개하는 효과에 관하여 연구모형을 구축하고 검증하기 위한 목적으로 실시되었다. 조사는 2008년 8월 1일에서 9월 31일까지 진행되었으며, 남양주시 및 동두천시의 17개 경로당의 노인 330명을 대상으로 실시하였다. 본 연구의 결과를 요약하면, 총 9개의 직접효과에 관한 가설 중 6개의 가설이 지지되었다. 즉 죽음불안을 내생변수로 건강상태, 우울, 사회적지지의 직접효과가 유의하였으며, 주관적 삶의 질을 내생변수로 우울, 사회적 지지, 죽음불안의 직접효과가 유의하였다. 간접효과의 경우 총 4개의 간접효과가설 중 2개의 간접효과가 유의하였다. 즉 주관적 건강상태가 주관적 삶의 질에 미치는 효과를 죽음불안이 매개하는 효과가 유의하였으며, 우울이 주관적 삶의 질에 미치는 영향을 죽음불안이 매개하는 효과가 유의하였다. 본 연구의 결과에 기초하여 노인의 죽음불안 경감을 위한 제언을 제시하였다.

• Communications for Statistical Applications and Methods
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• 제27권5호
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• pp.547-568
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• 2020

Modeling the statistical autocorrelations in spatial data is often achieved through the estimation of the variograms, where the selection of the appropriate valid variogram model, especially for small samples, is crucial for achieving precise spatial prediction results from kriging interpolations. To estimate such a variogram, we traditionally start by computing the empirical variogram (traditional Matheron or robust Cressie-Hawkins or kernel-based nonparametric approaches). In this article, we conduct numerical studies comparing the performance of these empirical variograms. In most situations, the nonparametric empirical variable nearest-neighbor (VNN) showed better performance than its competitors (Matheron, Cressie-Hawkins, and Nadaraya-Watson). The analysis of the spatial groundwater dataset used in this article suggests that the wave variogram model, with hole effect structure, fitted to the empirical VNN variogram is the most appropriate choice. This selected variogram is used with the ordinary kriging model to produce the predicted pollution map of the nitrate concentrations in groundwater dataset.

• 설비공학논문집
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• 제25권12호
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• pp.660-667
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• 2013

This study presents a numerical investigation of the heat and mass transfer kinetics of a fin-tube-type adsorption bed using a two-dimensional numerical model with silica-gel and water as the adsorbent and refrigerant pair. The performance is strongly affected by the heat and mass transfer in the adsorption bed, but the details of the mass transfer kinetics remain unclear. The validity of inter-particle models used to simulate mass-transfer kinetics were examined, such as a constant pressure model and non-constant pressure model, and the valid ranges of the diffusion ratio for each model are proposed. The COP and SCP have been numerically calculated as the performance indexes according to the diffusion ratio. The constant pressure model, which is commonly used in previous research, was found to be valid only in a limited range of diffusion ratio.

• Management Science and Financial Engineering
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• 제12권1호
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• pp.127-142
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• 2006

In this paper, we present a frequency reassignment problem (FRP) that arises when we add new base stations to resolve hot-spots or to expand the coverage of a code division multiple access (CDMA) network. For this problem, we develop an integer programming (IP) model along with some valid inequalities and preprocessing rules. Also, we develop an effective heuristic procedure that solves two sub-problems induced from the original problem in repetition. Computational results show that the proposed heuristic procedure finds a feasible solution of good quality within reasonable computation time. Also, the lower bound by-produced from the heuristic procedure is quite strong.

• 임상간호연구
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• 제17권1호
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• pp.101-112
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• 2011

Purpose: The purpose of this study is to develop a detailed clinical model for recording initial nursing assessment items, and to test the applicability of the model to facilitate semantic interoperability for sharing and exchanging nursing information. Methods: First, the researchers extracted items by analyzing initial nursing assessment records. Second, defining characteristics were identified by analyzing nursing records and reviewing the literature. Third, value sets for defining characteristics were identified and types and cardinalities of defining characteristics were defined based on the value sets. Finally, the detailed clinical model was tested through evaluation by experts and comparison with the initial nursing assessment in a clinical setting. Results: Sixty-one detailed clinical models were developed with 178 defining characteristics and value sets. The experts evaluation and comparison with the initial nursing assessment in a clinical setting showed that the detailed clinical model developed in this study was valid. Conclusion: Use of this detailed clinical model can ensure that the Electronic Health Record contains meaningful and valid information and supports semantic interoperability of nursing information. This use will promote quality in the nursing records and eventually quality of nursing care.

• Bulletin of the Korean Chemical Society
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• 제33권3호
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• pp.885-892
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• 2012

Energy transfer dynamics of excited vibrational energy of OH stretching bonds in liquid water is theoretically studied. With time-dependent vibrational Hamiltonian obtained from a mixed quantum/classical calculation, we construct a master equation describing the energy transfer dynamics. Survival probability predicted by the master equation is compared with numerically exact one and we found that incoherent picture of energy transfer is reasonably valid for long-time population dynamics. Within the incoherent picture, we assess the validity of independent pair approximation (IPA) often introduced in the theoretical models utilized in the analysis of experimental data. Our results support that the IPA is almost perfectly valid as applied for the vibrational energy transfer in liquid water. However, proper incorporation of radial and orientational correlations between two OH bonds is found to be critical for a theory to be quantitatively valid. Consequently, it is suggested that the Forster model should be generalized by including the effects of the pair correlations in order to be applied for vibrational energy transfer in liquid water.

• 한국정보과학회논문지:소프트웨어및응용
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• 제26권10호
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• pp.1167-1167
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• 1999

Although spatial databases support an efficient spatial management on objects in the real world, they have a characteristic that process only spatial information valid at current time, So in case of change in the spatial domain, it is very hard to support an efficient historical management for time-varying spatial information because they delete an old value and then replace with new value that is valid at current time. To solve these problems, there are rapidly increasing of interest for spatiotemporal databases, which serve historical functions for spatial information as well as spatial management functions for an object. However most of them presented in an abstract time-varying spatial phenomenon, but have not presented a concrete policy in spatiotemporal databases. In this paper, we propose a spatiotemporal data model that supports bitemporal time concepts in three dimensional architecture. In the proposed model, not only data types and their operation for object of spatiotemporal databases have been classified, but also mathematical expressions using formal semantics for them have been given. Then, the data structures and their operations based on relational database model as well as object-oriented database model are presented.

• 유통과학연구
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• 제12권9호
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• pp.95-99
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• 2014

Purpose - This study aims to develop and empirically test a multi-dimensional service convenience scale with the dimensions and measurement items of service convenience perceived by Korean consumers in retail contexts. Research design, data, and methodology - The study adopts the framework suggested by Berry et al. (2002) and conceptualizes service convenience as a second-order reflective construct comprising 31 items. Three department store chains (Hyundai, Lotte, and Shinsegae) and three discount store chains (E-mart, Homeplus, and Lotte Mart) were involved 510 valid responses were used for the empirical testing. Results - The measurement model is acceptable for internal consistency, convergent validity, and discriminant validity. Further, the structural model results show that service convenience is positively related to satisfaction. Results of the rival model comparison indicate that the proposed second-order factor model provides a better fit to the data than both the five-factor and the one-factor model. Conclusions - The multi-dimensional, second-order conceptualization of service convenience is robustly supported. This study provides psychometrically valid scales to measure service convenience in retail contexts as conceptualized by Berry et al. (2002).

• Asia pacific journal of information systems
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• 제15권3호
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• pp.91-109
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• 2005

According to traditional theories of information systems, one of the reasons for using information technology is that users believe it to be helpful or useful for what they want to do, which is called extrinsic motivation. However, in addition to extrinsic motivation, there are other reasons for using it such as enjoying or playing with information technology itself, called intrinsic motivation, and just others around users, called social influence. The objective of this study is to provide a research model for using information technology considering intrinsic and extrinsic motivation, and social influence. For validation of this model, we survey the users of 'Minihompy' since it is one of the most popular blog services in Korea and there are relatively clear extrinsic and intrinsic motivation, and social influence respectively in using it. By analysing 549 valid samples by Partial Least Square(PLS), we show the suggested research model to be a valid one. That is, all hypotheses we suggested turn out to be statistically significant and $R^2$ of the dependent variable, the intention of use, explaining by the model to be higher than 40%. In addition to validation of the research model, it is found that intrinsic motivation may be more important than extrinsic motivation and social influence in using information technology.

• JSTS:Journal of Semiconductor Technology and Science
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• 제13권3호
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• pp.213-223
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• 2013

A unified channel thermal noise model valid in all operation regions is presented for short channel MOS transistors. It is based on smooth interpolation between weak and strong inversion models and consistent physical model including velocity saturation, channel length modulation, and carrier heating. From testing for noise benchmark and comparing with published noise data, it is shown that the proposed noise model could be useful in simulating the MOSFET channel thermal noise in all operation regions.