Volume 6, Issue 2

Abstract. The use of inertial sensors (accelerometer and gyroscopes) for evaluation of movement disorder motion, including essential tremor (ET) and Parkinson's disease (PD), is becoming prevalent. This paper uses a novel combination of six degree-of-freedom motion analysis and coherence based processing methodologies to uncover differences in the signature of motion for the ET and PD movement disorders. This is the first analysis of such motions utilizing the novel methodology outlined, and it displays a distinct motion profile differentiating between these two groups. Such an analysis can be used to assist medical professionals in diagnosing movement disorders given a currently high error rate of diagnosis. As well, the Kalman smoothing analysis performed in this paper can be quite useful for any application when tracking of human motion is required. Another contribution of the work is the use of wavelets in zero phase lag filtering, which helped in preparing the data for analysis by removing unwanted frequencies without introducing distortions into the data.

Abstract. The access to the high resolution digital terrain models (DEM) generated from the data collected by the Shuttle Radar Topography Mission (SRTM) of NASA is freely available to the public. Consequently it has become a source of topographic information which is of great value to scientists involved in geophysical or geodetic analysis. Despite the efforts of the Consultative Group on International Agricultural Research (CGIAR), to validate and complement the information contained in these DEMs (currently offered as version 4.1), they still need to be checked for their accuracy in certain regions of the planet. In this paper, the vertical accuracy of the SRTM 3" version 4.1 DEM was analyzed in several areas of Peru using two sets of control points: the height of the district capitals (the minor politics units) and the heights of the weather and hydrological stations from the National Meteorology and Hydrology Service (SENAMHI) of Peru. The comparison shows that the height differences are independent of the altitude, latitude and longitude of the evaluated points. They are rather related to the aspect of the terrain and to the way the SRTM data were acquired. It shows that the mean square of the height differences at national level was ±20 m for district capitals and ±25 m for the SENAMHI stations. This is slightly larger than the overall accuracy of the SRTM ±16 m.

Abstract. A lot of publications deal with the effect of the root network of the vegetation on near surface slope movements but the effect of the vital processes of the vegetation on soil deformation has been less investigated till now. In this presentation relationships between vital processes of the plants and small movements of the slope are shown. For monitoring stream bank movements, two geodetic test sites were established on the high loess bank of the River Danube at Dunaföldvár and Dunaszekcső in Hungary. On the Dunaföldvár test site two and on the Dunaszekcső test site three highly sensitive borehole tiltmeters were also installed for continuous monitoring of movements. The records of the tiltmeters show a daily variation with variable magnitude in the range of some microradians. From our previous research we know that these small movements are in close connection with the ground water variations. Vegetation maps were made for both test sites. The temperature and precipitation was continuously recorded. On the basis of these data and the vegetation map the potential evapotranspiration was calculated for both sites. Values of the potential evapotranspiration and precipitation were compared to the micro-tilts of the high loess banks at Dunaföldvár and Dunaszekcső. It was pointed out that the daily tilt amplitudes are in close connection with the vital processes of the plants. Our investigation showed that the vegetation can play an important role in hindering landslides occurrence since by planting appropriate vegetation on slopes the infiltration of the precipitation into the deep layers of the slope and so the moistening of the high bank can be significantly diminished.

Abstract. Using GPS-levelling technique for height determination has been a very attractive method in recent years, due to rapid availability of high quality GPS positioning. With this method, a precise geoid is required to convert GPS ellipsoidal heights to orthometric heights. Conventionally, such a high quality local geoid is obtained through very dense gravity and GPS-levelling data (and other gravity related quantities, such as vertical deflections, gravity gradients). However, high quality and dense gravity and GPS-levelling data are not available for many developing countries, due to the cost and effort for such surveys. In this paper, a simple alternative method based on recent high quality global gravity and digital terrain models, which avoids the need of dense gravity and GPS-levelling data, is proposed. With this method, low and medium wavelength gravity field structures are estimated from the recent global gravity model, the Earth Gravitational Model 2008 (EGM2008), while the short wavelength structures are calculated from the latest global Digital Terrain Model (the Shuttle Radar Topography Mission (SRTM) elevation data). Residual topography reduced geoid undulation differences between GPS-levelling and EGM2008 are modeled as a trend and a corrective surface separately. As the GPS-levelling data used in this method is relatively sparse, an iterative cross-validation method is used to maximize the available data points in the corrective surface computation. As an example, a very rough region (in Canadian Rocky mountains) is selected to test this geoid determination method. The comparison of the geoid using the proposed method with the Canadian Gravimetric Geoid 2005 (CGG2005) in absolute and relative sense shows a slight improvement and the new geoid is able to be used to support GPS-levelling in the second and third order height networks.

Abstract. Compact vector formulas are given for the great ellipse on the spheroid providing vector solutions to both the forward and the inverse problems and conversions of longitude and latitude. The solution incorporates a closed form for the azimuth and the derivation of this equation is presented and illustrated. This paper also shows that a computer algebra system and linear algebra are powerful tools to solve some mathematical derivations that may be useful in navigation, geodesy, and cartography.