Judul: Kajian Paleoklimatologi dan Perubahan Suhu Global
Abstrak: Global climate change is a change of climate patterns and intensity on a global scale as a result of changes in the energy budget components within the earth system and may be caused by both natural and antrophogenic factors. Studies of climate change requires a long data which may be reconstructed by several methods of paleoclimatology including ice cores, tree ring, coral, and pollen methods. Climate reconstruction using Ice core method requires longer data records compared with the tree ring, coral, and pollen method. The complexity of physical and chemical analysis are major constaints in utilizing ice core and coral method. On the other hand, the unven speard of tree on the earth cause limitations to the information obtained from tree ring and pollen method. Among factors consider important to the global climate change include solar constant, properties of earth surface, and atmospheric chemical compositions of greenhouse gases. Radiative forcing is an index defined by the rate of energy change per unit area of the globe as measured at the top of the atmosphere. Global climate change is indicated by increased of global average surface temperature which according to data records has increased by 0.7oC during the last century. A number of literature suggest the temperature rise was due to anthropogenic factors; however, using simplified energy balance model of the earth-atmosphere system reveals that an increase of solar constant by 1% (which may occur during the last century), while holding other factors unchanged, will result in an average global surface temperature increase of 0.6oC which is fairly close to the value obtained from observations. It must be emphasized that climate is an extremely complex system in which various factors interact with each other in some forms of linear and non-linear feedbacks. Analysis of time series data of Jakarta Observatory which cover a period of 1965-2010 shows a slight increase of average temperature and decrease of average rainfall.
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Judul: Analysis of increasing ext reme weather intensity in Jabota (Jakarta, Bogor, Tangerang) Period 1980 - 2008
Abstrak: spaces. This changes causes rising of air temperatures and hence increasing frequent events of extreme weather. Based on research in Taiwan, China and Japan, its have been proven that the existence of rising temper ature and frequent extreme weather were caused by land use changes. Daily observed data from Meteorological Stations around urban area of Jabota during the period 1980-2008 was used to determine the increase of air temperature and the frequency of extreme weather events. Besides the surface air temperature, the upper air temperature data period 1988-2008 was also analysed data to examine the increase of air temperature at particular layer. Further, hourly weather data of 2003-2008 from Meteorological Stasion Curug has been used as an example to analyze the time shifts of maximum air temperature and the time of thunderstorms occurrence. The analysis resulted an increase in average temperature in the latest period; increasing frequency of temperatures above 34° C, the increasing frequency of extreme precipitation at some months, especially in the rainy and transition seasons; the increasing frequency of thunderstorms occurrence, the increase of average upper air temperature, especially at surface layer up to 500 mb layer. The results also showed that the maximum temperature occurrence at certain months in dry and transition season to 02: 00 pm and the mostly hour of thunderstorms occurrence was 03: 00 to 05: 00 and from 07: 00 to 08: 00 pm.
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Judul: Construction of Strongly Optimal Binary Linear Code with Minimum Distance 9 and 11
Abstrak: A binary linear code of length n over q F is a subspace of n q F . A code has three parameters that attached to it, namely length, dimension, and minimum distance. A code with length n, dimension k and minimum distance d is often called [n, k, d ]-code. Usually, when two parameters are given, then we want to find a code that has the best value for the last parameter. Based on Gilbert- Varshamov bound, if a [n, k, d ]-code exists and can not be expanded, we call it a strongly optimal code. In this paper, we construct strongly optimal code with minimum distance 9 and 11. In constructing the code, we created a theorem and algorithm based on Gilbert-Varshamov bound before we implement the algorithm to MAPLE programming language. Because of computational limitations, the program can only construct up to k = 10 for d = 9 and k = 12 for d = 11.
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