• Journal of Korean Society of Transportation
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• v.4 no.2
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• pp.3-14
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• 1986

This study was undertaken to develop the gap acceptance model of left-turn drivers on the major road at intersections. Typical unsignalized intersections on the two-lane and four-lane streets in Masan City were selected for the study intersection. For the gap distribution model, the lognormal, negative exponential, shifted negative exponential, and Gamma distributions were tested using the x2 and K-S tests. Based on the results for both streets, it was concluded that among the distributions tested the lognormal distribution represented the gap distribution best, followed by the shifted negative exponential distribution. Stochastic models of the gap-acceptance behavior of left-turn drivers on the major road at unsignalized intersections were programmed using SLAM Ⅱ, a simulation computer language. A stochastic model was selected for the gap-acceptance behavior to compare the results of the simulation with the observed data. The model assumes that a fixed critical acceptance gap is assigned to each left-turn driver based on a normal distribution and the gap distribution of the opposing traffic stream follows the shifted negative exponential distribution.

• Journal of the Korea institute for structural maintenance and inspection
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• v.28 no.2
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• pp.1-8
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• 2024

The expansion joint is installed to offset the expansion of the superstructure and must ensure sufficient gap during its service life. In detailed guideline of safety inspection and precise safety diagnosis for bridge, damage due to lack or excessive gap is specified, but there are insufficient standards for determining the abnormal behavior of superstructures. In this study, a data-based maintenance was proposed by continuously monitoring the expansion-gap data of the same expansion joint. A total of 2,756 data were collected from 689 expansion joint, taking into account the effects of season. We have developed a method to evaluate changes in the expansion joint-gap that can analyze the thermal movement through four or more data at the same location, and classified the factors that affect the superstructure behavior and analyze the influence of each factor through deep learning and explainable artificial intelligence(AI). Abnormal behavior of the superstructure was classified into narrowing and functional failure through the expansion joint-gap evaluation graph. The influence factor analysis using deep learning and explainable AI is considered to be reliable because the results can be explained by the existing expansion gap calculation formula and bridge design.

• Transactions of the Korean Society of Mechanical Engineers
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• v.9 no.1
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• pp.56-63
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• 1985

Methods for evaluating the added masses of square and hexagonal structures with fluid gap are presented. For a sufficiently small fluid gap, an analytical expression for the added mass is found using the method of matched asymptotic expansion. Experimental data and numerical results using finite element method are also obtained for various sizes of fluid gap. It is shown that added masses increase in inverse proportion to the fluid gap as it becomes smaller. Experimental data, theoretical and numerical results are in good agreement.

• International Journal of Computer Science & Network Security
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• v.24 no.3
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• pp.113-124
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• 2024

One of the goals of the Saudi Arabia 2030 vision is to ensure full employment of its citizens. Recruitment of graduates depends on the quality of skills that they may have gained during their study. Hence, the quality of education and ensuring that graduates have sufficient knowledge about the in-demand skills of the market are necessary. However, IT graduates are usually not aware of whether they are suitable for recruitment or not. This study builds a prediction model that can be deployed on the web, where users can input variables to generate predictions. Furthermore, it provides data-driven recommendations of the in-demand skills in the Saudi IT labor market to overcome the unemployment problem. Data were collected from two online job portals: LinkedIn and Bayt.com. Three machine learning algorithms, namely, Support Vector Machine, k-Nearest Neighbor, and Naïve Bayes were used to build the model. Furthermore, descriptive and data analysis methods were employed herein to evaluate the existing gap. Results showed that there existed a gap between labor market employers' expectations of Saudi workers and the skills that the workers were equipped with from their educational institutions. Planned collaboration between industry and education providers is required to narrow down this gap.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.7
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• pp.512-519
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• 2009

Flow pulsation in the gap connecting with two parallel channels is investigated by RANS and URANS approaches. The two parallel channels are connected by a small channel called for a gap. The parallel channels are designed to have different cross section area with its ratio of 0.5. Computations are conducted using a CFX 11.0 code. The bulk Reynolds number is 60,000. Predicted results are compared with the previous experimental data. Mean velocity profile at the center of gap region are compared with experiments for its validation. Spectral analysis on the lateral velocity in the center of the gap was performed. Auto correlation for the axial-flow velocity pattern was presented. The unsteady structure of the flow pulsation was visualized in the region of the gap in the parallel channel.

• Elastomers and Composites
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• v.30 no.3
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• pp.235-246
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• 1995

When an O-ring is installed in a high fluid pressure device, a section of the O-ring is extruded into the piston-cylinder clearance gap. Any tendency towards extrusion will induce wear in dynamic applications, leading to premature failure of the seal. In this study, the mechanism of initial extrusion of the O-ring was studied, 1.e., how much amount of the O-ring will be extruded into the clearance gap at a certain pressure. The relationship between extrusion depth and a clearance gap or fluid pressure were studied by finite element analysis (FEA). After that, Salita's experimental data were analyzed. The result is that Initial extrusion depth for an O-ring into a clearance gap was 1.11 times the product of dimensionless pressure difference $(p-p_1)/E$ and clearance gap c. The required pressure $p_1$ for zero extrusion depth was found to decrease logarithmically with increasing clearance gap.

• Communications for Statistical Applications and Methods
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• v.20 no.4
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• pp.283-290
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• 2013

Subjects can experience two types of recurrent events in a longitudinal study. In addition, there may exist intermittent dropouts that results in repeated observation gaps during which no recurrent events are observed. Therefore, theses periods are regarded as non-risk status. In this paper, we consider a special case where information on the observation gap is incomplete, that is, the termination time of observation gap is not available while the starting time is known. For a statistical inference, incomplete termination time is incorporated in terms of interval-censored data and estimated with two approaches. A shared frailty effect is also employed for the association between two recurrent events. An EM algorithm is applied to recover unknown termination times as well as frailty effect. We apply the suggested method to young drivers' convictions data with several suspensions.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.1004-1008
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• 2003

Near-filed optical storage using cantilever aperture tip is a promising way fer next generation optical data storage. To enhance the speed of reading and writing data, gap between tip and media should be controlled fast and precisely within near field region. In this paper, several PZT actuators are analyzed far constructing dual servo control algorithm: coarse actuators(stact. PZT, bimorph PZI) for media surface inclination and One actuator(film PZT) for media surface roughness. Dynamic analysis of stack PZT, bimorph PZT, and film PZT are performed through the frequency response. Based on the frequency response and mathematical model, fast analog controller is designed.

• Journal of the Korean Data and Information Science Society
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• v.26 no.6
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• pp.1377-1386
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• 2015

GDP gap is closely related with economic activity of a country as a whole, especially with the economic fluctuations which is called business cycle. GDP gap is regarded as an important variable for the monetary policy of the central bank because it provides information on the excess demand pressures and employment matters. However, GDP gap may not provide enough information of the effect of recent economic structural change or the environmental change of domestic and external economic condition. In this paper, the GDP is decomposed by statistical filtering techniques and various models are fitted to estimate the influence of GDP gap on Inflation and see if it has been changed. Analysis results show that the influence of GDP gap on inflation decreased in the 2000s while that of global GDP gap increased. These results also support that recent low inflation rate is due to the change of overseas economic condition, such as a slowdown in exports resulting from the global recession, as well as domestic factors.

• Journal of Korean Academy of Nursing Administration
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• v.6 no.2
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• pp.259-279
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• 2000

This study is a descriptive analytic research measuring nursing service quality, using SERVQUAL model, to make fundamental data and strategies for nursing service improvement. Data were collected by self-reported questionnaire from 202 patients and 142 nurses, from June 7 to 14, 1999. The reliability of instrument were adequate(Cronbach ${\alpha}=.94$). SAS program was utilized for statistical analysis of collected data. The results were as follows; 1. There was a gab between patient's expectation and perception on nursing service(Gap B). Gap D was indicated an affecting factor to decide nursing service quality. Gap C was indicated an indirect affecting factor of nursing service quality. Because it was not statistically significant in total item analysis, but in individual item analysis, 7 items were appeared statistically significant. Gap A was not a gap occurrence factor of nursing service quality. 2. Focuses of nursing service quality improvement strategies were; (1) to direct qualitative improvement of nursing service in order to correspondence patient's nursing service expectation. (2) to make nurse's service activity modified because nurse's practice were not reached patient's expectation level. (3) to need internal, external factor analysis affecting nurse's service activity. 3. Nursing service quality was decided by rather environmental inappropriateness provided nursing service than itself. Therefore, to make nursing service quality improvement, it is required to improve nursing service environment. For this, followings are required; (1) to strengthen nurse's education on lower part of nursing service satisfaction and QI activities. (2) to balance demand and supply of nursing personnel. 3) to fix computerized system for reducing other duties weight except nursing care through analysis of nursing activity. (4) to construct rational cooperating system among related departments. 4. The important parts for nursing service quality improvement were indicated as follows: (1) Gap B: 'prompt reaction', 'examination symptom before patient's complaint', 'hearted nursing service reducing patient's dissatisfaction', 'explanation goals of nursing activities', 'having special Knowledge enough', 'maintenance position comfortably', 'management of patient's physical hygiene'. (2) Gap C: 'maintenance physical safety', 'explanation about hospital rules and facilities'. (3) Gap D: 'tender, safe injection and wound care'. Because above items are mostly improved through nurse's attitude change and quality improvement, it is required to establish nursing standardization and to strengthen nurse's clinical education. As the based on above results, followings are suggested; 1. SERVQUAL model is very useful to make strategies for nursing service quality improvement because it indicates multiple factors affecting hap occurrence. 2. At individual items analysis of Gap C, statistically significant 7 items appeared higher nurse's perception level than patient's perception level on nursing service were trouble perception level on nursing service quality improvement. So. it need further research to analysis about these difference occurring factors. 3. At analysis of Gap D, it is indicated that in nursing service performance process, multiple factors lowing nursing service quality were intruded. So it needs further research to analysis what these factors are and how each factors affect on nursing performance process. 4. nursing service quality measurement is changeable according to sample select time or sampled subject's characteristics. So to develope strategy for nursing service quality improvement is based on the results of periodical analysis.