Tecnura

13-26

Authors: Cesar Hernandez, Jefferson Jara Estupiñan, Diego Armando Giral Ramirez

Context: Modeling and prediction of spectrum use by PUs is an important aspect to reduce interference between SUs and PUs, and improve the performance of the spectral decision. This requires past spectral information, which allows the algorithm to model the behavior of the PU. Objective: Determine the optimal value of past samples and time to recalculate decision criteria for decision-making algorithms in cognitive radio networks. Methodology: Several simulation experiments are performed from the FFAHP algorithm, in two different approaches, real-time and best-effort, with high and low traffic, in the GSM frequency band. A statistical analysis of the data obtained is performed, varying the time range parameters, while time criteria remains constant, and vice versa. Results: For high traffic it is enough to take 1800 previous samples to calculate the initial value of the parameters and update them every 10 minutes (1800). If the traffic is low, it is enough to take 5400 previous samples to calculate the initial value of the parameters and update them every 10 minutes (1800). Conclusions: A large number of previous samples is not necessary to determine the initial value of the decision parameters to obtain a good performance of the handoff rate, nor is it necessary for updating them, for traffic corresponding to the band of GSM frequency. Funding: This work is a result of a research project funded by the Center for Research and Scientific Development of the Francisco José de Caldas District University.

39-48

Authors: Hernando Carlos Oñate Barraza, Gridis Yulieht Cortez Henao

Objective: The purpose of this article is to qualify the conditions of the Cesar river stream in the area of influence of the dumping of the STAR of the municipality of Valledupar, and its relationship with the biological indicators of contamination and BMWP/COL quality index. Methodology: Four sampling stations were established on the Cesar River: E1 and E2 located upstream of the mixture zone at the municipal wastewater discharge point, E3 located at the point of mixing of the discharge and the river; and E4 located downstream of the discharge, letting know its physicochemical characteristics and to determine the biological conditions of the stream according to the BMWP/COL index for each of the established stations. Results: In stations E1 and E2, macroinvertebrates indicators of clean and well-oxygenated waters were obtained, with an acceptable water classification; while the stations E3 and E4, were found macroinvertebrates indicators of contaminated waters of doubtful quality; E4 has being the most critical area, with oxygen and BOD5 concentrations of 4.61 mg/L and 51.42 mg/L respectively. Conclusions: The station E4 shows the quality of the most contaminated water according to the index applied, since despite the presence of individuals from the Hemiptera and Trichóptera genus that receive a high score in the BMWP index, also, the appearance of groups of macro invertebrates indicators of poor quality waters such as the Diptera of the family Ephydriidae, Culicidae and Chironomidae.

64-73

Authors: Luis Hernando Montoya Armenta, Yim James Rodríguez Díaz

Objective: The general objective of this research was to understand the effect of floods on the transport of particulate matter and organic carbon in the forest basin of Oka river during three hydrological years (October 2009 to September 2012). Methodology: A hydrometeorological station installed at the catchment outlet allowed continuously capture data from: precipitation, discharge, turbidity, among other. The regression relationship between field turbidity (TRB) and solid suspended concentration (CSS) measured in the laboratory was established with a linear function. The loading of suspension solids (SS), dissolved organic carbon (DOC) and particulate organic carbon (COP) was determined as the product of the flow rate and the concentration of each parameter for each time interval, and was applied throughout the study period. Results: The total export of SS, COD and COP was estimated at 2267,5 t, 104,2 t and 53,2 t respectively, representing rates of 71,85, 3,30 and 1,68 t km-2 y-1, as mean for the three years in study. Conclusions: Statistical analyses showed that total precipitation, flood discharge and flood volume, were the major factors controlling SS, COD and COP transport from the catchment. High seasonal and monthly variability in SS, COD and COP transport occurred in the catchment. Sediment was mainly transported during autumn and winter, when frequent flood events of high magnitude and intensity occurred. However, exceptional flood events occur during different seasons of the year, influencing the transport of sediments and associated contaminants. Financing: University of the Basque Country / Euskal Herriko Unibertsitatea (UNESCO Project 08/15).

85-101

Authors: Guadalupe de la Lanza Espino, Salvador Hernández Pulido, Francisco José Gutiérrez Mendieta

Context: The wide variation in coastal physicochemical and biological parameters are the result of natural local factors: climate, geomorphology, marine influence, river discharges, such as anthropogenic, resulting in wide variations and this has resulted in the use of averages that do not reflect aquatic reality Therefore, the present study analyzes the theoretical behavior of the conservative and non-conservative and biological parameters of coastal lagoons of both the Gulf of Mexico and the Mexican Pacific, through data referred to as minimum, maximum and average, and their degree of certainty. Methodology: Physicochemical and biological information was collected from 11 coastal lagoons with extreme environmental differences: five from the Gulf of Mexico and six from the Mexican Pacific, according to the availability and continuity of the information. Results: The intervals of the conservative and non-conservative parameters (maximum and minimum) were significantly wide, associated with seasonal climatic factors (rainfall and drainage), temporary or permanent river discharges, water management in the adjacent land area, as well as by tidal influence. Therefore, using an average based on maximum and minimum of those parameters is not recommended. In the non-conservative parameters, there were short or larger differences in variation; due to the dynamics of circulation, epoch, even, to the annuity until the interannuality, so it is not advisable to use averages. Based on the above, greater variations in aquatic parameters were estimated in the lagoons of the Pacific and greater homogeneity in those of the Gulf of Mexico, as a result of fluvioclimatic regularity, less anthropogenic influence and less coastal management. Conclusions: For a diagnosis results with an integrative view of coastal physicochemical and biological factors, it is necessary to rely on knowledge of local normal conditions that include: physical, river, geomorphological dynamics and adjacent terrestrial influences, to differentiate from anthropogenic impacts, which they modify the aquatic characteristics; therefore, it is not appropriate to refer the results as minimum, maximum and average that in many cases the interval between the first and the last can be wide, with insecure and erroneous results; in addition to not being repetitive or permanent and vary heterogeneously, as could be seen in the chosen lagoons of the Gulf of Mexico and the Mexican Pacific. Keywords: physicochemical parameters, coastal lagoons of Mexico