NONCORRALATED DATA ORDERED SAMPLES AS A SINGLE-ELEMENT MULTICHANNEL CONVERTER

The sufficient closeness of the medians of the ordered samples of random data to the normal distribution is used in computer systems for control, monitoring and diagnosing electric power equipment. However, it remains what other probability density function (pdf) of elements (sample statistics) have such similarities. This paper presents various methods for statistical testing hypotheses for pdf-converter channels as statistics of given sizes odd numbered and ordered samples of bounded and uniformly distributed random numbers. The use of various different criteria and the results of estimates studied under the same conditions showed a sufficient conformity of the results of tests for three statistical criteria. It made possible to draw a reasonable conclusion about the preferable use of the adapted chi-square test for assessing the congruence of analytical pdf channels of the converter with normal distribution. We also suggested using the "statistical closeness window" to define those channels of the converter that do not significantly differ from the normal distribution. In addition, we presented an empirical formula determining the dependence of the size of the window of the statistical closeness window on the sample size. The results of the research are summarized in a statistical model of a multichannel uncorrelated data converter. References 27, figures 7.

Sensor Technology for Night Sky Brightness Measurements in Malaysia

Artificial light at night is apparently showing to be a major contributor to the increase of sky brightness at night. The natural darkness in large regions of the world including Malaysia currently is at risk. Hence, some Night Sky Brightness (NSB) measurements in Malaysia were conducted by using several types of light sensors in order to serve quantitative data and spread awareness on this issue. This paper aims to analyze the sensor technology that have been used in night sky brightness measurement in Malaysia as well as to identify recent or significant advances and discoveries in this field of study. In this paper, the author adopted qualitative method through literature review from numerous conducted studies by other researchers in order to perceive better understanding on the use of dedicated light sensor in NSB related research. Starting from 2005 until now, it is noticeable that most of the light sensor used in the NSB studies in Malaysia was Sky Quality Meter (SQM) photometer, equipped with TSL237 sensor which has high irradiance responsivity 2.3kHz/(µW/cm2) @ λp = 524nm and 5 Milion:1 input dynamic range as well as able to sense down to 0.00002 Lux and has typical dark frequency down to 0.1 Hz. The result indicates the relative frequency of the SQM usage in NSB studies was 76% compared to PBM, APC, PMT and CDD of only 4% respectively. SQM has always been the choice of researchers in Malaysia to carry out their sky brightness measurements due to user-friendly implementation besides its reliable data obtained from TSL237 sensor which capable to convert the light directly to frequency without an amplifier or data converter. Thus, the nonlinearities and voltage offsets in the data can be circumvented. A fairly good development of sensor that have been utilized in NSB studies can be discerned patently besides NSB studies will always look forward for a better sensor to further enhance the efforts to map sky brightness for preserving the potential dark sky areas for the sake of astronomy.