Filtering the LiDAR point cloud based the Unmaned Aerial Vehilce (UAV - LiDAR) in the dense land cover areas to build a Digital Terrain Model (DTM) is a basic requirement of large-scale topographic mapping. The aim of this paper is to study the use of the Simple Morphological Filter (SMRF) with suitable parameters to separate the non-terrain points (trees, noise points, etc.) and the topographical points. The methods of this article are algorithmic programming and combining the two filtering algorithms including SMRF and distributed filtering. The various data input was studied in the Ba Be case study. These parameters include the grid width called Gcell (m), the radius of filters called nwd and the threshold of the feature elevation called Eth (m). The point cloud of the terrain obtained after applying the SMRF continues to be filtered using distributional filter with the algorithm keeping only minimum elevation in the filtering window in order to remove the locations of high density of points. Then, it will contribute to lighten the point capacity to build DTM, to accurately interpolate the contour lines and to ensure the aesthetics of large-scale topographic maps. The results of the study are the fomulas to estimate reasonable input parameters (Gcell = 3 m, nwd = 3, Eth = 0.2 m) of the two filters for the establishment of a topographic map of 1:2000 scale, 1 m level in the Ba Be national forest, Bac Kan province, Vietnam.

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The Semi-Direct Injection (SDI) system has been shown to improve small engine efficiency and exhaust by utilizing a lean burn method. In order to better understand how to more readily utilize the control systems in SDI engine, the real-time operation of an SDI engine was modeled. A charging model was developed by using a filling-and-emptying model to simulate air exchange in an engine, including varying the intake manifold structure. A single-zone model was applied to a combustion model and the effects of air/fuel ratio and swirl ratio on combustion duration were also considered. The calculated results of the intake manifold pressure, heat release rate, and cylinder pressure were compared with the experimental data. The results of this study show that this modeling process approximates reality.