• KSII Transactions on Internet and Information Systems (TIIS)
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• v.18 no.7
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• pp.1868-1887
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• 2024

Recommendation systems research is a subfield of information retrieval, as these systems recommend appropriate items to users during their visits. Appropriate recommendation results will help users save time searching while increasing productivity at work, travel, or shopping. The problem becomes more difficult when the items are geographical locations on the ground, as they are associated with a wealth of contextual information, such as geographical location, opening time, and sequence of related locations. Furthermore, on social networking platforms that allow users to check in or express interest when visiting a specific location, their friends receive this signal by spreading the word on that online social network. Consideration should be given to relationship data extracted from online social networking platforms, as well as their impact on the geolocation recommendation process. In this study, we compare the similarity of geographic locations based on their distance on the ground and their correlation with users who have checked in at those locations. When calculating feature embeddings for users and locations, social relationships are also considered as attention signals. The similarity value between location and correlation between users will be exploited in the overall architecture of the recommendation model, which will employ graph convolution networks to generate recommendations with high precision and recall. The proposed model is implemented and executed on popular datasets, then compared to baseline models to assess its overall effectiveness.

• Journal of the Society of Naval Architects of Korea
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• v.54 no.5
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• pp.421-429
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• 2017

It is very important to manage the position of the blocks in the shipyard where the work is completed, or the blocks need to be moved for the next process operation. The moving distance of the block increases according to the position of the block stockyard. As the travel distance increases, the number of trips and travel distance of the transporter increases, which causes a great deal of operation cost. Currently, the selection of the block position in the shipyard is based on the know-how of picking up a transporter worker by the production schedule of the block, and the location where the block is to be placed is determined according to the situation in the stockyard. The know-how to select the position of the block is the result of optimizing the position of the block in the shipyard for a long time. In this study, we used the accumulated data as a result of the operation of the yard in the shipyard and tried to select the location of blocks by learning it. Decision tree learning algorithm was used for learning, and a prototype was developed using it. Finally, we prove the possibility of selecting a block stockyard through this algorithm.

• Geophysics and Geophysical Exploration
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• v.7 no.1
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• pp.80-87
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• 2004

During excavation work for the construction of a highway bridge in a limestone area in Korea, several cavities were found, and construction work was stopped temporarily. Cavities under the bridge piers might seriously threaten the safety of the planned bridge, because they could lead to excessive subsidence and differential settlement of the pier foundations. In order to establish a method for reinforcement of the pier foundations, borehole radar reflection and tomography surveys were carried out, to locate cavities under the planned pier locations and to determine their sizes where they exist. Since travel time data from the crosshole radar survey showed anisotropy, we applied an anisotropic tomography inversion algorithm assuming heterogeneous elliptic anisotropy, in order to reconstruct three kinds of tomograms: tomograms of maximum and minimum velocities, and of the direction of the symmetry axis. The distribution of maximum velocity matched core logging results better than that of the minimum velocity. The degree of anisotropy, defined by the normalized difference between maximum and minimum velocities, was helpful in deciding whether an anomalous zone in a tomogram was a cavity or not. By careful examination of borehole radar reflection and tomography images, the spatial distributions of cavities were delineated, and most of them were interpreted as being filled with clay and/or water. All the interpretation results implied that two faults imaged clearly by a DC resistivity survey were among the most important factors controlling the groundwater movement in the survey area, and therefore were closely related to the development of cavities. The method of reinforcement of the pier foundations was based on the interpretation results, and the results were confirmed when construction work was resumed.

• Journal of Korean Society of Transportation
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• v.19 no.5
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• pp.119-134
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• 2001

This paper proposed a dynamic transit vehicle simulation model and a dynamic transit passengers simulation model, which can simultaneously simulate the transit vehicles and passengers traveling on a transit network, and also developed an algorithm of dynamic departure time choice model based on individual passenger. The proposed model assumes that each passenger's behavior is heterogeneous based on stochastic process by relaxing the assumption of homogeneity among passengers and travelers have imperfect information and bounded rationality to more actually represent and to simulate each passenger's behavior. The proposed model integrated a inference and preference reforming procedure into the learning and decision making process in order to describe and to analyze the departure time choices of transit passengers. To analyze and evaluate the model an example transit line heading for work place was used. Numerical results indicated that in the model based on heterogeneous passengers the travelers' preference influenced more seriously on the departure time choice behavior, while in the model based on homogeneous passengers it does not. The results based on homogeneous passengers seemed to be unrealistic in the view of rational behavior. These results imply that the aggregated travel demand models such as the traditional network assignment models based on user equilibrium, assuming perfect information on the network, homogeneity and rationality, might be different from the real dynamic travel demand patterns occurred on actual network.

• Economic and Environmental Geology
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• v.18 no.2
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• pp.151-157
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• 1985

Events detected by the KIER microearthquake network operated in the Southern Part of Korea for 265 days in 1982~1984 were reviewed, and some of them were identified to be a dynamite explosion from several construction sites. The purpose of the present work is to determine the crustal structure of the Southern Korea using the time-destance data obtained from such explosion seismic records. The time·distance data can be well explained by a crustal model composed of four horizontal layers of which thickness, p and s-wave velocity ($V_p$ and $V_s$) are characterized as follows. 1st layer (surface) ; 0~2km, $V_p=5.5km/sec$, $V_s=3.3km/sec$ 2nd layer (upper crust) ; 2~15km, $V_p=6.0km/sec$, $V_s=3.5km/sec$ 3rd layer (lower crust) ; 15~29km, $V_p=6.6km/sec$, $V_s=3.7km/sec$ 4th layer (upper mantle) ; 29km~ , $V_p=7.7km/sec$, $V_s=4.3km/sec$ The relatively shallow crust·mantle boundary and low $P_n$ velocity compared with the mean values for stable intraplate region are noteworthy. Supposedely, it is responsible for the high heat flow in the South-eastern Korea or an anomalous subterranean mantle. The mean $V_p/V_s$ ratio calculated from the relation between p-wave arrival and s-p arrival times appears to be 1.735 which is nearly equivalent to the elastic medium of ${\lambda}={\mu}$. However, the ratio tends to be slightly larger with the depth. The ratio is rather high compared with that of the adjacent Japanese Island, and the fact suggests that the underlying crust and upper mantle in this region are more ductile and hence the earthquake occurrences are apt to be interrupted. As an alternative curstal model, a seismic velocity structure in which velocities are successively increased with the depth is also proposed by the inversion of the time·distance data. With the velocity profile, it is possible to calculate a travel time table which is appropriate to determine the earthquake parameters for the local events.

• Journal of Families and Better Life
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• v.5 no.2
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• pp.11-27
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• 1987

This study examined job satisfaction levels between employed single women and employed married women. The specific objectives of this study were; (1) to investigate differences in the level of job satisfaction between employed single women and employed married women; (2)to investigate the factors which influence the level of job satisfaction; (3)to investigate the relationship between job satisfaction and life satisfaction. the data used in this study included 441 working women from 290 (65.8 %) single women and 151 (34.2%) married women. Statistical analyses were conducted using frequencies, percentiles, mean , t-test , ANOVA, pearson's correlation and a stepwise multiple regression. The major findings were ; (1) at the P<.005 level, there was a significant difference in the job Satisfaction Index (JSI) between employed single and married women by using the t-test ; (2) Occupation, type of organization , job experiences, travel time from home to work. unionization, age, and health status were significantly related to the JSI by using the one-way ANOVA; (3) Thee was an interaction effect between income and marital status on the JSI, and between education and marital status on the JSI; (4) Using a stepwise multiple regression method, the order of variables as they were entered in the model were different between employed single and married women; (5) There was a positive relationship between the JSI and Life Satisfaction Index(r=.41)

• Journal of Families and Better Life
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• v.32 no.1
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• pp.63-79
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• 2014

Recently, in our society, the use of smartphones has been widespread and changed our lives positively; however, the excessive use of smartphones has also produced many side effects. In particular, we can see that the reckless use of smartphones has constantly increased smartphone addiction propensities. University students, too, show smartphone addiction propensities more and more gradually; therefore this study intends to perform research related with smartphone addiction propensities with university students as the subjects. Since it is more and more important to perform leisure activities to prevent smartphone addiction and reduce addiction propensities, it can be said that the research on the correlation between leisure activities and smartphone addiction propensities is significant. The major findings of the research are as follows: First, among the smartphone addiction propensities, their tolerance and disturbance of adaptive function were relatively higher than other factors. Second, overall smartphone addiction affects the variables of gender (male), school year (freshmen), economic leisure constraints, time leisure constraints, and the adequacy of travel behavior, sports behavior, media use behavior, reading behavior, volunteer work and religious behavior. The adequacy of the media use behavior variables showed the greatest impact.

• Journal of the Korea Construction Safety Engineering Association
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• s.55
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• pp.37-51
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• 2012

There is a shround of mystery surronnding Gaudi. In all probability, the first mist preventing us from gaining acess to his work is the intrinstic mysteriousness of all genius and, at the end of the day, of all human spirit. The situation is complicated by the well-known fact that Gaudi wished to creat an aura of silence around his persona, while, at the same time as maintaining this secretiveneness - in other words, the annihiliation of his fundamental values-gave expression and symbolisation to his moods and incerdible mental power. On a piece of land on the Muntanya Pelada, in the Barcelona district of La Salut, Eusebi G$\ddot{u}$ell Wanted to build an urbanisation inspired by the concepe of the garden city. in this he sought to return to nature, health and an escape from the insalubrous industrial city. Gaudi worked on the construction of this park between 1900 and 1914, and even moved his home there in 1906. An outstanding feature of park G$\ddot{u}$ell is the integration of architecture with nature. In other to save the natural slopes, Gaudi built viaducts from brick pillars, which he covered with stone obtained from the excavation.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1196-1202
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• 2007

In construction of high speed railway, the fan shape is limited to achieve reduction of required travel time and concrete railway which has structural stability and induces small maintenance cost with allowable ground settlement is recently applied. So construction of concrete railway on soft ground in which considerable ground settlement occurs increases and settlement management in soft ground section is required. Field monitoring on ground movement and integrated geotechnical information system which manages construction, design, and field monitoring data are essential for settlement management of concrete railway subgrade. Site investigation data are also required due to future repair work. Therefore in this study, integrated geotechnical information system for construction and maintenance of concrete railway is developed. The developed system consists of a database and an application program. The database contains site investigation, construction, design, and field monitoring data throughout a railway. Application program performs various functions on managing and utilizing information in the database with graphic visualization of output. And by providing integrating information with comprehensible visual displays, the applicability and effectiveness of the developed system for construction and maintenance management were confirmed.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.11 s.176
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• pp.51-58
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• 2005

Laser surface hardening technologies have been used to improve characteristics of wear and to enhance the fatigue resistance for automotive parts. The objective of this research work is to investigate the influence of the process parameters, such as power of laser and defocused spot position, on the characteristics of laser heat treatment for the case of SM45C medium carbon steel. CW Nd:YAG laser is selected as the heat source. The optical lens with the elliptical profile is designed to obtain a wide heat treatment area with a uniform hardness. From the results of the experiments, it has been shown that the maximum hardness is approximatly 780 Hv when the power and the travel speed of laser are 1,095 W and 0.6 m/min, respectively. In addition, the hardening width using the elliptical lens was three time larger than that using the defocusing of laser beam.