• Journal of Korean Society of Coastal and Ocean Engineers
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• v.21 no.2
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• pp.117-126
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• 2009

In order to test the accuracy between the modified mild slope equation (MMSE) without evanescent modes and the plane-wave approximation (PA) of eigenfunction expansion method, various numerical results from both models are presented. In this study, analytical solutions of two models are employed, one based on the MMSE derived by Porter (2003) and the other on the scatterer method of PA by Seo (2008a). Judging from direct comparisons against existing results of rapidly varying topography, the PA model gives better predictions of the wave propagation than the MMSE model.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.7 no.2
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• pp.141-147
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• 1995

Various numerical models for predicting wave deformation have been proposed. Among them a time-dependent mild-slope equation based on the line discharges and surface-elevation changes has been widely used in the wave fields with reflective waves. If applying this model to the case of obliquely-incident waves, not only the open-sea boundary but also one of the lateral boundaries should be treated as incident boundaries. In this study, Maruyama and Kajima (1985), Copeland (1985) and Ohnaka and Watanabe (1987)'s method are reviewed and the characteristics of these methods are analyzed using e normalized wave heights, wave angels and phases obtained from the numerical experiments. It is shown that Ohnaka and Watanabe(1987)'s method provides the most adequate driving boundary is the most suitable in e wave field with a general bottom slope.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2004.11a
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• pp.90-95
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• 2004

During the past 50 years methods for predicting wave overtopping of coastal structures have coastal structures have continuously been developed Wave overtopping is one of the most important processes for the design of seawalls. The term 'wave overtopping' is used here to refer to the processes where waves hit a sloping structure run up the slope and, if the crest level of the slope is lower than the highest run up level, overtop the structure. Wave overtopping is dependent on the processes associated with breaking wave. The Numerical model is based on Navier-Stokes equation and Marker-Density Function of method for nonlinear free-surface flow by Miyata & Park(1995). The influence of how the slopes of seawalls, wave type and crest freeboard affect overtopping discharges has been investigated. The research of study using the new development nonlinear free-surface flow numerical model SOLA-VOF are presented.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.214-214
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• 2015

Rainfall induced landslides is one of the most devastating natural disasters acting on mountainous areas. In Korea, landslide damage areas increase significantly from 1990s to 2000s due to the increase of both rainfall intensity and rainy days in addition with haphazard land development. This study was carried out based on the application of TRIGRS unsaturated (Transient Rainfall Infiltration and Grid-based Regional Slope stability analysis), a Fortran coded, physically based, and numerical model that can predict landslides for areas where are prone to shallow precipitation. Using TRIGRS combining with the geographic information system (GIS) framework, the landslide incident happened on 27th, July 2011 in Mt. Umyeon in Seoul was modeled. The predicted results which were raster maps showed values of the factors of safety on every pixel at different time steps show a strong agreement with to the observed actual landslide scars in both time and locations. Although some limitations of the program are still needed to be further improved, some soil data as well as landslide information are lack; TRIGRS is proved to be a powerful tool for shallow landslide susceptibility zonation especially in great areas where the input geotechnical and hydraulic data for simulation is not fully available.

• Phonetics and Speech Sciences
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• v.3 no.1
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• pp.145-151
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• 2011

In view of the hypothesis that the effects of Parkinson's disease on voice production can be detected before pharmacological intervention, the prosodic features of patients with idiopathic Parkinson's disease (IPD) and a healthy aging group were diagnostically analyzed with the long term object of establishing, for clinical purposes, early disease-progression biomarkers. Twenty patients (male 8; female 12) with IPD (prior to pharmacological intervention) and a healthy control group of 22 (male 10; female 12) were selected. Ten sentences were recorded with a head-worn microphone. One sentence was chosen for the analysis of this paper. Relevant parameters, i.e. 3-dimensional model (F0, intensity, duration) and pitch and intensity related slopes (maxEnergy, maxF0, meanAbS, semiT, meanEnergy, meanF0), were analyzed by two-group discriminant analysis. The stepwise estimation method of discriminant analysis was performed by gender. The discriminant functions predicted 83.9% of the male test data correctly while the prediction rate was 93.1% for the female group. The results showed that meanF0_slope and semiT_slope were more important parameters than the others for the male group. For the female group, the meanEnergy_slope and maxEnergy_slope were the important ones. These findings indicate that significant parameters are different for the male and female group. Gender lifestyle may be responsible for this difference. Dysprosodic features of IPD show not simultaneously but progressively in terms of F0, intensity and duration.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.22 no.2
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• pp.79-85
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• 1989

The generation and propagation of shelf wave-like oscillations induced by local wind at a basin with continental shelf and slope are studied by a numerical experiment. Three types of vortices are generated along western boundary and they propagate along the boundaries in the counter-clockwise direction. The first vortex is generated at the early stage of wind stress and its center is located off the continental slope. The second type centered on the continetal slope is generated at about the terminating time of wind stress and follows the first one. The third, centered on continental shelf, decays so soon that its propagation pattern is hard to be identified. Each of those vortices is probably to be one of free modes of the model basin.

• The Journal of Engineering Geology
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• v.21 no.3
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• pp.247-257
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• 2011

In this study the infinite slope model, one of the physical landslide models has been suggested to evaluate the susceptibility of the landslide. However, applying the infinite slope model in regional study area can be difficult or impossible because of the difficulties in obtaining and processing of large spatial data sets. With limited site investigation data, uncertainties were inevitably involved with. Therefore, the probabilistic analysis method such as Monte Carlo simulation and the GIS based infinite slope stability model have been used to evaluate the probability of failure. The proposed approach has been applied to practical example. The study area in Boeun area been selected since the area has been experienced tremendous amount of landslide occurrence. The geometric characteristics of the slope and the mechanical properties of soils like to friction angle and cohesion were obtained. In addition, coefficient of variation (COV) values in the uncertain parameters were varied from 10% to 30% in order to evaluate the effect of the uncertainty. The analysis results showed that the probabilistic analysis method can reduce the effect of uncertainty involved in input parameters.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.35 no.2
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• pp.33-40
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• 2023

Wave overtopping rate is one of the most important design parameters for coastal structures. In this study, the physical model tests for measuring the wave overtopping have been conducted with the foreshore slope in front of the seawall. The bottom seabed for the coastal road area was fabricated at the wave flume for two areas in the East sea areas. The wave overtopping rate was measured for various water depths and wave conditions in each coastal area. In particular, the impulsive wave conditions were compared with the previous research and the similar trends of wave overtopping was observed. It could be known that the effect of foreshore slope was significant and should be concerned for applying theses formula like EurOtop.

• Magazine of the Korean Society of Agricultural Engineers
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• v.44 no.4
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• pp.85-98
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• 2002

The purpose of this study is to develop a land use planning model (LUPM) which can be applied to development of rural villages considering their spatial expansion. The LUPM finds out and allocates the new built site required for the improvement of existing villages. in the development of LUPM, CA (cellular automata) and land suitability analysis methods were applied combinedly. The model uses basically numerical data of CIS based on grid data. Agglomerated settlement, as a type of village for simulation, was adopted. Probability of land use change for optimizing development area was calculated by the six criteria: slope. drainage characteristic, direction of slope, as absolute suitability of grid itself, distance from road. distance from stream and distance from the village center, as relative probability by neighborhood cells. Weighting values of these criteria were quantified by AHP (analytic hierarchy process) method, which is one of MCE(multi-criteria evaluation) method. The algorithm of the model was verified by three example villages: an isolation village, a village with horizontal road, and a village with nodal point of cross road

• The Journal of Engineering Geology
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• v.30 no.4
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• pp.649-661
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• 2020

Cut-slope management system (CSMS) has been investigated all slopes on the road of the whole country to evaluate risk rating of each slope. Based on this evaluation, the decision-making for maintenance can be conducted, and this procedure will be helpful to establish a consistent and efficient policy of safe road. CSMS has updated the database of all slopes annually, and this database is constructed based on a basic and detailed investigation. In the database, there are two type of data: first one is an objective data such as slopes' location, height, width, length, and information about underground and bedrock, etc; second one is subjective data, which is decided by experts based on those objective data, e.g., degree of emergency and risk, maintenance solution, etc. The purpose of this study is identifying an data application plan to utilize those CSMS data. For this purpose, logistic regression, which is a basic machine-learning method to construct a prediction model, is performed to predict a judging-type variable (i.e., subjective data) based on objective data. The constructed logistic model shows the accurate prediction, and this model can be used to judge a priority of slopes for detailed investigation. Also, it is anticipated that the prediction model can filter unusual data by comparing with a prediction value.