Application that demonstrates the operation of network devices written in Java

Sieci komputerowe w ciągu ostatnich lat stały się nieodłącznym elementem naszego życia. Ciężko nam sobie wyobrazić świat bez internetu, czy też telefonów komórkowych. Pomimo iż historia tej dziedziny nauki liczy sobie około sześćdziesiąt lat z pewnością można stwierdzić, że w tym czasie zaszło wiele zmian, zarówno tych mniejszych, jak i tych wręcz rewolucyjnych. Wszystko to sprawiło, że sieci komputerowe stały się dziedziną bardzo obszerną i złożoną, a większość użytkowników nie jest zaznajomionych nawet z podstawami ich działania. Dlatego celem niniejszej pracy było napisanie aplikacji w języku Java, która zaprezentuje sposób działania różnych urządzeń sieciowych takich jak: koncentrator sieciowy, przełącznik sieciowy, ruter, czy też zapora sieciowa. Program daje użytkownikowi możliwość zbudowania sieci z gotowych komponentów, prostej konfiguracji oraz uruchomienia symulacji, po zakończeniu której wyświetlone zostaje podsumowanie. Aplikacja przeznaczona jest w szczególności dla osób niezaznajomionych z tematyką sieci komputerowych. Jest to narzędzie umożliwiające zrozumienie podstawowych urządzeń oraz stosowanych technik. Poczynienie pierwszych kroków bywa nieraz bardzo trudne i frustrujące. Zadaniem niniejszej aplikacji jest uczynienie procesu nauki szybszym, łatwiejszym oraz przyjemniejszym.Computer networks in recent years have become an integral part of our lives. It's hard for us to imagine a world without the Internet or mobile phones. Despite the fact that the history of this field of science dates back to about sixty years, it can certainly be said that during this time many changes took place, both smaller and even revolutionary. All this has made computer networks a very large and complex field, and most users are not even familiar with the basics. Therefore, the aim of this work was to write an application in Java, which will present the operation of various network devices, such as: a hub, a switch, a router, or a firewall. The program allows the user to build a network from ready-made components, to perform a simple configuration and run a simulation, after which a summary is displayed. The application is intended in particular for people unfamiliar with the subject of computer networks. It is a tool to understand the basic devices and techniques. Taking the first steps can be very difficult and frustrating at times. The purpose of this application is to make the learning process faster, easier and more enjoyable

Unequal homologous recombination of human DNA on a yeast artificial chromosome.

We examined unequal homologous DNA recombination between human repetitive DNA elements located on a yeast artificial chromosome (YAC) and transforming plasmid molecules. A plasmid vector containing an Alu element, as well as a sequence identical to a unique site on a YAC, was introduced into yeast and double recombinant clones analyzed. Recombination occurs between vector and YAC Alu elements sharing as little as 74% identity. The physical proximity of an Alu element to the unique DNA segment appears to play a significant role in determining the frequency with which that element serves as a recombination substrate. In addition, cross-over points of the recombination reaction are largely confined to the ends of the repetitive element. Since a similar distribution of crossover sites occurs during unequal homologous recombination in human germ and somatic tissue, we propose that similar enzymatic processes may be responsible for the events observed in our system and in human cells. This suggests that further examination of the enzymology of unequal homologous recombination of human DNA within yeast may yield a greater understanding of the molecular events which control this process in higher eukaryotes

CONGENITAL FIBROSIS OF THE EXTRAOCULAR-MUSCLES (AUTOSOMAL-DOMINANT CONGENITAL EXTERNAL OPHTHALMOPLEGIA) - GENETIC HOMOGENEITY, LINKAGE REFINEMENT, AND PHYSICAL MAPPING ON CHROMOSOME-12

Congenital fibrosis of the extraocular muscles (CFEOM) is an autosomal dominant syndrome of congenital external ophthalmoplegia and bilateral ptosis. We previously reported linkage of this disorder in two unrelated families to an 8-cM region near the centromere of human chromosome 12. We now present refinement of linkage in the original two families, linkage analysis of five additional families, and a physical map of the critical region for the CFEOM gene. In each of the seven families the disease gene is linked to the pericentromeric region of chromosome 12. D12S345, D12S59, D12S331, and D12S1048 do not recombine with the disease gene and have combined lod scores of 35.7, 35.6, 16.0, and 31.4, respectively. AFM136xf6 and AFMb320wd9 flank the CFEOM locus, defining a critical region of 3 cM spanning the centromere of chromosome 12. These data support the concept that this may be a genetically homogeneous disorder. We also describe the generation of a YAC contig encompassing the critical region of the CFEOM locus. This interval has been assigned cytogenetically to 12p11.2-q12 and spans the centromere of chromosome 12. These results provide the basis for further molecular analyses of the structure and organization of the CFEOM locus and will help in the identification of candidate genes