The European Commission had approved the Registration, Evaluation and Authorization of Chemicals (REACH) regulations in the year 2006, and will begin to implement it form 1 June 2007. This regulation greatly increases safety of protection for the users of chemicals, but it also brought a problem for the manufactures as well as downstream users. That is they have to generate and distribute much more Material Safety Data Sheets (MSDS) then before. This work is difficult for most companies since this job usually was done manually. The new regulation requires a much more efficient method to generate and distribute them. This thesis project addresses the problem of automatically distributing MSDS and the corresponding metadata. It presents the underlying technology selected for this project. It gives a brief introduction of this project, the underlying technologies used, along with the methods used to deliver relevant and up to date materials safety information. At last an HTTP web application approach was selected to solve the problem, the resulting application can efficiently notify a downstream user of the newly updated MSDS and transport the corresponding file and metadata. It is truly data driven, therefore the downstream user does not need to check for updates everyday, instead will be notified when there is an available update. / Den Europeiska kommissionen antog 2006 en ny bestämmelse för informationsspridning av kemikalier, Registration, Evaluation, and Authorization of Chemicals (REACH), och den kommer att tas i bruk från första juni 2007. Bestämmelsen innebär ett starkt ökat skydd för användare av kemikalier, men den ställer även till problem för både tillverkare och användare. Exempelvis, de måste generera och distribuera betydligt fler materialsäkerhetsföreskrifter, Material Safety Data Sheets (MSDS), än tidigare. Detta arbete är krävande för de flesta företag eftersom arbetet ofta sker manuellt. Den nya bestämmelsen kräver mycket effektivare metoder att generera och distribuera MSDS. Det här examensarbetet fokuserar på problemet att automatiskt distribuera MSDS och den korresponderande metadatat. Rapporten presenterar den underliggande teknologin för examensarbetet. Därutöver ges en kort introduktion till examensarbetet, den underliggande teknologin, tillsammans med de metoderna som används för att skicka relevanta och aktuella materialsäkerhetsföreskrifter. Som avslutning väljs en HTTP Web applikationslösning för att lösa problemet. Den lösningen kan effektivt underrätta en användare att det finns en nyare MSDS och sedan skicka den korresponderande filen och dess metadata. Den är data driven, vilket gör att en användare inte måste kontrollera för uppdateringar varje dag, utan kommer att bli informerad när det finns en ny tillgänglig.

In this dissertation we take a peer-to-peer approach to deal with two specific issues, fair trading and file distribution, arisen from data management for cloud computing. In mobile cloud computing environment cloud providers may collaborate with each other and essentially organize some dedicated resources as a peer to peer sharing system. One well-known problem in such peer to peer systems with exchange of resources is free riding. Providing incentives for peers to contribute to the system is an important issue in peer to peer systems. We design a reputation-based fair trading mechanism that favors peers with higher reputation. Based on the definition of the reputation used in the system, we derive a fair trading policy. We evaluate the performance of reputation-based trading mechanisms and highlight the scenarios in which they can make a difference. Distribution of data to the resources within a cloud or to different collaborating clouds efficiently is another issue in cloud computing. The delivery efficiency is dependent on the characteristics of the network links available among these network nodes and the mechanism that takes advantage of them. Our study is based on the Global Environment for Network Innovations (GENI), a testbed for researchers to build a virtual laboratory at scale to explore future Internets. Our study consists of two parts. First, we characterize the links in the GENI network. Even though GENI has been used in many research and education projects, there is no systematic study about what we can expect from the GENI testbeds from a performance perspective. The goal is to characterize the links of the GENI networks and provide guidance for GENI experiments. Second, we propose a peer to peer approach to file distribution for cloud computing. We develop a mechanism that uses multiple delivery trees as the distribution structure, which takes into consideration the measured performance information in the GENI network. Files are divided into chunks to improve parallelism among different delivery trees. With a strict scheduling mechanism for each chunk, we can reduce the overall time for getting the file to all relevant nodes. We evaluate the proposed mechanism and show that our mechanism can significantly reduce the overall delivery time.

Denna uppsats behandlar ämnet filöverföring i ett nätverk. Fokus för arbetet har varit att undersöka MTU:ns inverkan på överföringshastigheten vid filöverföringar baserat på vilket protokoll som används och storleken på filerna som överförs. I arbetet har ett flertal experiment genomförts som syftat till att utreda detta, samt att finna vilket protokoll som överlag presterar bäst baserat på omständigheterna för överföringen. Olika filöverföringsprotokoll, fildistributionsprotokoll, MTU:er samt filstorlekar har testats för att finna vad som resulterar i högst överföringshastighet vid filöverföring över ett Ethernetnätverk. Resultaten visar på att en hög MTU uppnår högst överföringshastighet vid överföring av stora filer, men att en standard-MTU fungerar bättre för att överföra mycket små filer. / This report concerns the subject of file transfer. The focal point of the report is to study the effect that the MTU has on the speed of file transfers based on the protocol used and the size of the transferred files. During the course of the work, several experiments have been performed in order to determine this, as well as to find which protocol gives the overall best result based on the circumstances of the file transfers. Various file transfer protocols, file distribution protocols, MTUs and file sizes have been tested in order to find what results in the best file transfer speed over an Ethernet based network. The results show that a high MTU has the best performance when transferring large files, while a standard MTU gives better results for transferring very small files.