No abstract

TOR is known free tool for traffic anonymization on the Internet. The adverse aspect of using TOR is significant increase of overhead and decrease of the traffic speed. So far no study focusing the quantification of such decrease was published. TOR operation is based on "routing" the traffic through several nodes resulting in difficult and practically impossible direct calculation of the delay caused by TOR application. Therefore the study was performed to quantify the delay associated with using TOR comparing ordinary traffic. Www was used as a model of Internet traffic. The sample of 14 stable www pages and 8-10 files available via http throughout the world was chosen and the round-trip time was measured approx. 10 times both with TOR (at least in two configurations, first automatic and the second manually modified) and without TOR. For manual TOR measurement two onion routers were configured in two locations. Measurements were made in various days of week and various times to eliminate possible fluctuations due to varying traffic target www servers. The main result of the study is that the factor of roundtrip time increase varies between 2 and more than 100. In case of configured TOR networks the ratio is lower but still high,1.7 and 34. This is quite rough result that is shown in details in the article. The results show that TOR is useful anonymization tool but the delay caused by its use is enormous. Providing of more exact estimations would require more measurements however.

The study and the profession at the field of medicine involve high demands on mental and physical capabilities. The objective of this study is the following issue: in what ways mainly healthy students evaluate opportunities of students with special educational needs (SEN) to study medicine. It is based primarily on their experience of the studies and on their medical practice. To meet the above objective, a questionnaire survey method has been used. The results of the survey could be concluded with general recommendations: the study of general medicine is fully manageable for students with certain SEN such as slight visual or hearing impairments, specific learning disabilities, and internal diseases, while it is manageable in a limited way for students with physical disability of legs. The study of students with SEN such as severe visual or hearing impairment, locomotor disability of the upper limbs and disability of fine motoric skills and mental illness, will be very difficult and complicated even if the university considerably adapts to these conditions. In the case of students with SEN, making the decision regarding future profession in health care should always be realistic and based on individuals and with respect to their future employability.

No abstract

The vocal apparatus serves phonation. It represents a biocybernetic self-regulating system, disposing of a feedback network of the central nervous system. The larynx is a self-induced vibrating system. The larynx, functioning as the phonation apparatus of the vocal apparatus, is a source of human voice. In every individual its frequency range corresponds to about eight semitones in speech and about two octaves of the so-called chest register in singing, denoted also as a thoracic or modal voice. This is followed by one more octave of the so-called cranial register or falsetto voice. We were interested in changes of the larynx positions at intonation in the fundamental singing registers, both modal and falsetto, in professional male singers. At our disposal were 11 professional male singers. We investigated changes in the position of the laryngeal structures simultaneously with the aid of an X-ray apparatus, the acoustic and mechanical signals registered by means of the B & K 4369 acceleration recorder. It has been found that at phonation with the modal voice a change in the position of the laryngeal structures takes place in two different ways, whereas the larynx movements at falsetto remain the same. It has been suggested that a complex fixation apparatus participates in the phonation larynx movements. Of the same complex character are also the problems connected with the examination of the entire vocal apparatus. For the purpose of compiling the present pieces of knowledge in the field of human voice studies, we have made the most advantageous use of the presently most complex system Authorware for the production of some interactive multimedial programmes on personal computers.