• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.218-218
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• 2000

Advanced Vehicle Control Systems(AVCS) is one of the key elements in Intelligent Transportation Systems(ITS). This paper considers the problem of longitudinal control in vehicle platoon on a straight lane of a highway. In a very simplified situation, longitudinal vehicle dynamics contains many nonlinear elements. The nonlinear characteristics are mainly composed of an engine, a torque converter, and a drag force. In this paper, sliding control, one of nonlinear control methods, is applied to longitudinal automated vehicle control for platooning. Output feedback linearization is also simulated for comparison with the sliding control. Simulations for comparative study for the adopted controllers such as sliding control and output feedback linearization are peformed under the same conditions. This Paper aims at clarifying the characteristics of sliding control and output feedback linearization.

• Survey Research
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• v.7 no.2
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• pp.97-122
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• 2006

Korean Longitudinal Study of Ageing(KLoSA)', launched in 2006, has developed a research network with 'Health and Retirement Study(HRS, US),' Studies on Health and Retirement in Europe(SHARE, EU),' and 'English Longitudinal Study of Ageing(ELSA, UK)'and tried to construct a mega data library. The KLoSA team has designed their research with focusing on the following three points, in order to use KLoSA for international comparative studies. First, KLoSA shares the key research areas such as family structure, health, employment, income, asset, subjective expectations with the comparable studies. Second, KLoSA team has developed the instrument to reflect the Korean culture and institutions. They considered the institutional characteristics in public pension and health care system and in employment practices. They also counted the cultural conventions in family life such as financial management and care exchange, Finally, KLoSA tries to capture the psychological characteristics of the Korean elderly by making the measurement scales more understandable.

• Journal of Ship and Ocean Technology
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• v.3 no.4
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• pp.35-51
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• 1999

Fatigue strength assessment procedures have been implemented in the ship design rules by many classification societies. However, a large variation tin the details of the different approaches exists in practically all aspects influding load history assessment, stress evaluation and fatigue strength assessment. In order to assess the influences of thesd variations on the prediction of fatigue lives. a comparative study is organized by the ISSC Committee III.2 Fatigue and Fracture. A pad detail on the top of longitudinal hatch coaming of a panamax container vessel is selected for fatigue calculation. The work described in this paper is one set of results of this comparative study in which the ABS dynamics approach is applied. Through this analysis the following conclusions can be drawn. (1) With the original ABS approach, the fatigue life of this pad detail is very low, only 2.398 years. (2) The treatment of the stillwater bending moment in the ABS approach might be a source of conservatism. If the influence of stillwater bending moment is ignored, then the fatigue life for this pad detail is 7.036 years. (3) The difference between the nominal stress approach and the hot spot stress approach for this pad detail is about 26%.

• Journal of Korean Society of Water and Wastewater
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• v.20 no.5
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• pp.667-676
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• 2006

This study was conducted to evaluate the effect of longitudinal baffle on hydrodynamic behavior within a certain full-scale sedimentation basin (flow rate per basin; $1,000m^3/d$). Comparative experimental investigations have been carried out on the sediment removal efficiencies and the sludge deposit distribution in the baffled and un-baffled sedimentation basin, respectively. From the results derived in the baffled and un-baffled sedimentation, the turbidity removal rate in the baffled sedimentation basin is about 38% higher than that in un-baffled. Also, the height of sludge deposit in the baffled sedimentation basin is approximately 20% lower, and the sludge concentration is 10% higher than those in un-baffled sedimentation basin. In order to explain the experimental results and investigate the effect of longitudinal baffle in more detail, we conducted Computational Fluid Dynamics (CFD) simulation. From the results of CFD simulation, the flow, especially in the near of outlet orifice, was more stable in the case of longitudinal baffled sedimentation basin than that in un-baffled basin. Also, it could be concluded that the longitudinal baffle made a fully developed flow more effective for sedimentation.

• Journal of Wetlands Research
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• v.11 no.2
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• pp.89-98
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• 2009

This study determines the stream mean slope, stream slope and longitudinal stream profile based on the concept of informational entropy. Maximizing the entropy will make the probability distribution of longitudinal stream profile as uniform as possible while satisfying the constraints. Using this relationships the mean stream slope, stream slope and longitudinal stream profile formulas were derived. The parameters of the applied streams were estimated by the least square method using the geomorphological factors of Dalchon stream basin obtained from Chungcheong Buk-Do local stream consolidation scheme drawings. The comparative investigation was performed between the observed and simulated mean stream slope and longitudinal stream profile, and are in good agreement with the measured data. It is noted that this results can be used in the estimation of stream mean slope and longitudinal stream profile.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.10a
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• pp.410-413
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• 2008

In this study, we compare the mechanical properties of forged and machined bushings for an excavator track chain. The manufacturing process is explained in detail together with the procedure of making the specimens. The longitudinal tensile strength and elongation and the radial ring compression strength are measured for this comparison. It has been shown that the forged is much better than the machined with regard to both longitudinal tensile strength and radial ring compression strength but that both are the same in terms of longitudinal elongation.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.849-854
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• 2002

From the analysis results of some as-built drawings in national roadway bridges in Korea, many bridge piers are expected to show complex shear-flexural behaviour under earthquakes. But the previous research works about the seismic evaluation of bridges considered flexural behaviour RC piers only. In addition, the past bridge design specifications in Korea didn't include limitation on the amount of longitudinal lap splices in the plastic hinge zone of piers. Thus a large majority of non-seismically designed bridge piers in Korea may have lap splices in plastic hinge zone. In this study, prototype pier was selected among existent bridge piers whose failure mode is expected to be complex shear-flexural mode. And then, full scale and 1/2 reduced scale model RC piers with various longitudinal lap splice details were constructed. From the quasi static test results on these model RC piers, the effect of longitudinal lap splices on the seismic performance of bridges piers was analyzed. And the seismic capacity of the non-seismically designed shear-flexural RC piers was evaluated.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2002.09a
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• pp.114-122
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• 2002

The ASCE formula of lifeline.soil interaction force is the basis of semi-analytical relationship for buried pipelines subjected to longitudinal permanent ground deformation due to seismic induced liquefaction. However, since the ASCE formula has been developed based on the stiffness of non-liquefied region, it is needed to modify for the varied stiffness of liquefied region. With this object, the consideration of decreasing effect of soil stiffness in liquefied region is made: i.e. the spatial distributions of pipeline-soil interaction force in liquefied region. It means that the improved formula can reflect various patterns of permanent ground deformation more realistically. Through the comparative analyses using both the improved and ASCE formula, the applicability of the improved and the limitation of the ASCE formula and semi-analytical relationship are discussed. Also, relative influences of various parameters are evaluated for the clarification of behavior of pipeline subjected to longitudinal permanent ground deformation due to liquefaction.

• Special Issue of the Society of Naval Architects of Korea
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• 2009.09a
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• pp.65-70
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• 2009

In case that tug boat pushes side structures of other large vessels to maneuver, it is required that contacted side structures of the maneuvered vessels have enough structural safety against tug push loads. The objective of this study is to evaluate the structural effect of carling which is installed between side longitudinal stiffeners. A comparative study of side structures with carling and without carling is performed to evaluate the effect of carling member by both FE analysis. According to the result, it is found that the carlings play effective role in the strength of side plates and side longitudinal stiffeners against tug push loads.

• The Journal of Bigdata
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• v.5 no.2
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• pp.155-170
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• 2020

The purpose of this study was to apply machine learning techniques (Decision Tree, Random Forest, XGBoost) to data from the 4th~6th year of the Seoul Education Longitudinal Study to find the factors predicting the career maturity of middle school students in Seoul city. In order to evaluate the machine learning application result, the performance of the model according to the indicators was checked. In addition, the model was analyzed using the XGBoostExplainer package, and R and R Studio tools were used for this study. As a result, there was a slight difference in the ranking of variable importance by each model, but the rankings were high in 'Achievement goal awareness', 'Creativity', 'Self-concept', 'Relationship with parents and children', and 'Resilience'. In addition, using the XGBoostExplainer package, it was found that the factors that protect and deteriorate career maturity by panel and 'Achievement goal awareness' is the top priority factor for predicting career maturity. Based on the results of this study, it was suggested that a comparative study of machine learning and variable selection methods and a comparative study of each cohort of the Seoul Education Termination Study should be conducted.