Optical burst switching is a novel switching concept which is a hybrid of optical packet switching and optical wavelength routing. In order to provide an efficient bandwidth utilization, various burst assembly and scheduling schemes for optical bursts are introduced. In this work, the effects of burst assembly techniques on the performance of the optical burst switching (OBS) technique and the characteristics of the network traffic are studied. In order to assemble IP packets to form optical bursts, a time threshold based technique and a hybrid technique, which is based on both time and size threshold, are employed. Self-similar IP traffic is applied to the ingress nodes of the optical network. The effects of the burst assembly algorithms, just after the bursts are formed, are studied in detail considering self-similarity, burst size, and burst formation delay. The performance of the horizon scheduling technique is studied under both burst assembly methods. Moreover, the characteristics of the traffic obtained at the egress nodes are studied in terms of burst size, and self-similarity.