ANALISIS PENGARUH TEGANGAN INDUKSI PETIR TERHADAP KUALITAS KOMUNIKASI DATA (Analysis of the Effects of Lightning Induced Voltage on the Quality of Data Communications)

Indonesia merupakan negara yang mempunyai hari guruh pertahun yang sangat tinggi dibandingkan dengan negera-negara lain. Kerapatan sambaran petir di Indonesia juga sangat besar yaitu 12/?km?^2/tahun, yang berarti pada setiap luas area 1 ?km?^2 berpotensi menerima sambaran petir sebanyak 12 kali setiap tahunnya [1]. Sambaran petir tidak langsung dapat menginduksi saluran telekomunikasi, mengalirkan (konduksi) gelombang elektromagnetik didalam jaringan telekomunikasi yang berupa tegangan induksi yang sering dianggap sebagai noise. Sinyal noise dapat mengganggu sinyal informasi yang berakibat informasi yang diterima Rx menjadi rusak atau salah dalam membaca informasi tersebut. Untuk meminimalisir gangguan jaringan telekomunikasi khususnya pentransmisian sinyal informasi maka perlu diketahui efek yang ditimbulkan dari gangguan atau noise tersebut sehingga diketahui faktor yang dapat meminimalisir pengaruh yang terjadi. Pada tugas akhir ini menggunakan metode perhitungan model teori rusck, modulasi BFSK dan pemodelan AWGN untuk mengetahui nilai tegangan induksi yang dapat menurunkan kualitas BER dan SNR suatu komunikasi data. Hasil pengujian sistem simulasi pada tugas akhir ini menunjukkan bahwa sistem komunikasi data menjadi tidak layak untuk digunakan ketika nilai tegangan induksi lebih dari sama dengan 8.0611 volt dan nilai SNR kurang dari sama dengan 1.8721 db, karena nilai tersebut menghasilkan nilai BER yang tidak memenuhi standar kualitas komunikasi data. Kata kunci : Tegangan induksi, BFSK, AWGN, SNR, BER

Enhancing the Quality of Data on Income and Wealth

Over the last decade or so, a substantial effort has gone into the design of a series of methodological investigations aimed at enhancing the quality of survey data on income and wealth. These investigations have largely been conducted at the Survey Research Center at the University of Michigan, and have mainly involved two longitudinal surveys: the Health and Retirement Study (HRS), with a first wave beginning in 1992 and continued thereafter every other year through 2004; and the Assets and Health Dynamics Among the Oldest Old (AHEAD) Study, begun in 1993 and continued in 1995 and 1998, then in every other year through 2004. This provides and overview of the main studies and summarizes what has been learned about correcting longitudinal inconsistencies that arise.

Diffusion Tensor Imaging: on the assessment of data quality - a preliminary bootstrap analysis

In the field of nuclear magnetic resonance imaging, diffusion tensor imaging (DTI) has proven an important method for the characterisation of ultrastructural tissue properties. Yet various technical and biological sources of signal uncertainty may prolong into variables derived from diffusion weighted images and thus compromise data validity and reliability. To gain an objective quality rating of real raw data we aimed at implementing the previously described bootstrap methodology (Efron, 1979) and investigating its sensitivity to a selection of extraneous influencing factors. We applied the bootstrap method on real DTI data volumes of six volunteers which were varied by different acquisition conditions, smoothing and artificial noising. In addition a clinical sample group of 46 Multiple Sclerosis patients and 24 healthy controls were investigated. The response variables (RV) extracted from the histogram of the confidence intervals of fractional anisotropy were mean width, peak position and height. The addition of noising showed a significant effect when exceeding about 130% of the original background noise. The application of an edge-preserving smoothing algorithm resulted in an inverse alteration of the RV. Subject motion was also clearly depicted whereas its prevention by use of a vacuum device only resulted in a marginal improvement. We also observed a marked gender-specific effect in a sample of 24 healthy control subjects the causes of which remained unclear. In contrary to this the mere effect of a different signal intensity distribution due to illness (MS) did not alter the response variables

The Effect of Unfolding Brackets on the Quality of Wealth Data in the HRS

A characteristic feature of survey data on household wealth is the high incidence of missing data—roughly one in three respondents who report owning an asset are unable or unwilling to provide an estimate of the exact amount of their holding. A partial solution to that problem is to devise a series of questions that put the respondent’s holdings into a quantitative range (less than x, more than x, or what?). These quantitative ranges are called unfolding brackets, and they represent a survey innovation that aims to improve the quality of wealth data by substituting range data for completely missing data. In this paper, we examine the effect of unfolding brackets on the quality of HRS wealth data. Special attention is given to the impact of unfolding bracket entry points on the distribution of asset holdings in HRS 1998. Although there is a small positive relationship between mean asset holdings and entry point, there are many cases where that relationship does not hold. In general, our conclusion is that entry point bias problems are not a major concern in the evaluation of quality in the 1998 HRS wealth data.

Enhancing the Quality of Data on Income: Recent Developments in Survey Methodology

In this paper, we evaluate two survey innovations aimed at improving income measurement. These innovations are (1) integrating the question sequences for income and wealth which may elicit more accurate estimates of income from capital than has been true in the past, and (2) changes in the periodicity over which income flows are measured, which may provide a closer match between what the survey respondent knows best and the periodicity contained in survey measurement. These innovations have been introduced into both the Health and Retirement Study (HRS) and the study of Asset and Health Dynamics Among the Oldest Old (AHEAD). Based on the results reported in this paper, the potential return in quality of income measurement from these innovations is substantial.

Trade in Services: Note on the Measurement and Quality of Data Sources

This note gives a comprehensive overview of the currently available international databases on trade in services. Notwithstanding problems in data collection arising from the very wide definition of trade in services (i.e. the four GATS modes in contrast to what is traditionally considered as trade in merchandise goods), we identify a considerable room for improvement of the data situation also with respect to Balance of Payments based data. In this paper we survey IMF, OECD, Eurostat and OENB data at the most detailed sector level. We further give a short descriptive overview of Austria's relative position in service trade flows compared to its major trading partners.export of services, services trade data, services FDI data, Austria