Measurement of Negative Lightning Return Strokes Using a Proposed Small-Scale Parallel Plate Antenna at the Central Region in Peninsular Malaysia

Lightning can occur between the clouds (intra-clouds), ground-to-cloud (CG), and inside the clouds. The lightning strike hazards can be managed appropriately using a lightning detector system consisting of an antenna, buffer amplifier circuit, and a measurement device. In this study, the development and fabrication of small-scale parallel plate antenna were carried out by reducing the physical height and antenna dimension to measure the generated electric fields. The experimental work was conducted at the rooftop of the College of Engineering, Universiti Tenaga Nasional (UNITEN), Selangor, Malaysia, from August 2019 to March 2020. The total number of 115 return strokes (RS) of negative lightning events were recorded during the measurement period. Characterization of seven types of criteria for negative return stroke has been analysed and compared to the existing parallel plate antenna with a similar climate condition and different countries. Based on the comparative study, the proposed and the existing parallel plate antenna shows a good agreement. Hence, the proposed small-scale parallel plate antenna can be used as a portable, lightweight, and easy to install device for the lightning measurement system.

Towards a Global Unified Physical Height System

<p>The International Association of Geodesy (IAG), as the organisation responsible for advancing Geodesy, introduced in 2015 the International Height Reference System (IHRS) as the global conventional reference system for the determination of gravity field-related vertical coordinates. The definition of the IHRS is given in terms of potential parameters: the vertical coordinates are geopotential numbers (C<sub>P</sub> = W<sub>0</sub> ‐ W<sub>P</sub>) referring to an equipotential surface of the Earth's gravity field realised by the conventional value W<sub>0</sub> = 62 636 853.4 m<sup>2</sup>s<sup>‐2</sup>. The spatial reference of the position P for the potential W<sub>P</sub> = W(<strong>X</strong>) is given by coordinates <strong>X</strong> of the International Terrestrial Reference Frame (ITRF). At present, the main challenge is the realisation of the IHRS; i.e., the establishment of the International Height Reference Frame (IHRF): a global network with regional and national densifications, whose geopotential numbers referring to the global IHRS are known. According to the objectives of the IAG Global Geodetic Observing System (GGOS), the target accuracy of these global geopotential numbers is 3 x 10<sup>-2</sup> m<sup>2</sup>s<sup>-2</sup>. In practice, the precise realisation of the IHRS is limited by different aspects; for instance, there are no unified standards for the determination of the potential values W<sub>P</sub>; the gravity field modelling and the estimation of the position vectors <strong>X</strong> follow different conventions; the geodetic infrastructure is not homogeneously distributed globally, etc. This may restrict the expected accuracy of 3 x 10<sup>-2</sup> m<sup>2</sup>s<sup>-2 </sup>to some orders lower (from 10 x 10<sup>-2</sup> m<sup>2</sup>s<sup>-2</sup> to 100 x 10<sup>-2</sup> m<sup>2</sup>s<sup>-2</sup>). This contribution summarises advances and present challenges in the establishment of the IHRS/IHRF.</p>

The Effects of Stunting And Psychosocial Stimulus On The Development of Children Between The Age Of 2- 6 Years Old

Nutritional problems is the high rate of children under five with stunted physical development.This research aims to analyze the effects of stunting and psychosocial stimulation on the development of children between the ages of 2-6 years old.This is a observational analytical research with a case control approach, on a sample of 60 children of 2-6 years old.The degree of stunting is assessed using Z-score indicator,calculating children physical height per age.Meanwhile, for psychosocial stimulation, it is obtained through questionnaire filled by parents or caregivers. Children development is measured using Pre-Screening Developmental Questionnaire. Analyzed using chi-square test and logistic regression. Statistically, the sig. value according to chi-square test is 0,000. This value is smaller than 0,05, which can be concluded that stunting and psychosocial stimulus significantly affect child development. The result of multivariate test indicates that stunting and psychosocial stimulation variables have a significant influence on the development of a child (p<0,05).

The worldwide physical height datum project

The definition of a common global vertical coordinate system is nowadays one of the key points in Geodesy. With the advent of GNSS, a coherent global height has been made available to users. The ellipsoidal height can be obtained with respect to a given geocentric ellipsoid in a fast and precise way using GNSS techniques. On the other hand, the traditional orthometric height is not coherent at global scale. Spirit levelling allows the estimation of height increments so that orthometric heights of surveyed points can be obtained starting from a benchmark of known orthometric heights. As it is well known, this vertical coordinate refers to the geoid, which is assumed to be coincident to the mean sea level. By means of a tide gauge, the mean sea level is estimated and thus a point of known orthometric height is defined. This assumption, which was acceptable in the past, became obsolete given the level of precision which is now required. Based on the altimetry observation, one can precisely quantify the existing discrepancy between geoid and mean sea level that can amount to 1 ÷ 2 m at global scale. Therefore, different tide gauges provide biased estimates of the geoid, given the discrepancy between this equipotential surface and the mean sea level. Also, in the last years, another vertical coordinate was used, the normal height that was introduced in the context of the Molodensky theory. In this paper, a review of the existing different height systems is given and the relationships among them are revised. Furthermore, an approach for unifying normal height referring to different tide gauges is presented and applied to the Italian test case. Finally, a method for defining a physical height system that is globally coherent is discussed in the context of the definition of the International Height Reference System/Frame, a project supported by the Global Geodetic Observing System of the International Association of Geodesy (IAG). This project was established in 2015 during the XXVI IAG General Assembly in Prague as described in IAG Resolution no. 1 that was presented and adopted there.

On the applicability of a scan-based mobile mapping system for monitoring the planarity and subsidence of road surfaces – Pilot study on the A44n motorway in Germany

Kinematic laser scanning is widely used for the fast and accurate acquisition of road corridors. In this context, road monitoring is a crucial application, since deficiencies of the road surface due to non-planarity and subsidence put traffic at risk. In recent years, a Mobile Mapping System (MMS) has been developed at the University of Bonn, consisting of a GNSS/IMU unit and a 2D laser scanner. The goal of this paper is to evaluate the accuracy and precision of this MMS, where the height component is of main interest. Following this, the applicability of the MMS for monitoring the planarity and subsidence of road surfaces is analyzed. The test area for this study is a 6 km long section of the A44n motorway in Germany. For the evaluation of the MMS, leveled control points along the motorway as well as point cloud comparisons of repeated passes were used. In order to transform the ellipsoidal heights of the MMS into the physical height system of the control points, undulations were utilized. In this respect, a local tilt correction for the geoid model was determined based on GNSS baselines and leveling, leading to a physical height accuracy of the MMS of < 10 mm (RMS). The related height precision has a standard deviation of about 5 mm. Hence, a potential subsidence of the road surface in the order of a few cm is detectable. In addition, the point clouds were used to analyze the planarity of the road surface. In the course of this, the cross fall of the road was estimated with a standard deviation of < 0.07 %. Yet, no deficiencies of the road surface in the form of significant rut depths or fictive water depths were detected, indicating the proper condition of the A44n motorway. According to our tests, the MMS is appropriate for road monitoring.

The IAT Is Dead, Long Live the IAT: Context-Sensitive Measures of Implicit Attitudes Are Indispensable to Social and Political Psychology

The implicit association test (IAT) is one of several measures of implicit attitudes, but it has attracted especially intense criticism. Some methodological objections are valid, but they are damning only if one accepts false analogies between the IAT and measures of intellectual aptitude, clinical diagnosis, or physical height. Other objections are predicated on misconceptions of the nature of attitudes (which are context-sensitive and reflect personal and cultural forces) or the naive assumption that people cannot be biased against their own group. Other criticisms are ideological, pertaining to questions of moral and political value, such as whether it is good to have fewer pro-White/anti-Black implicit attitudes and to provide respondents with feedback about their implicit attitudes. Implicit-attitude measures have been extremely useful in predicting voting and other political behavior. An indirect, unobtrusive, context-sensitive measure of attitudes is far more useful to social and political psychologists than an IQ test or clinical “diagnosis” would be, insofar as it reflects a dynamic Lewinian conception of the “person in the situation.”