Database Coursework Example | Topics and Well Written Essays - 1250 words

Database - Coursework Example This allows or revokes access to the database for authorized users only. It also restricts on the actions that authorized users are allowed to perform on the database. This is the main method of securing data in a database. Access to the database mostly requires correct username and a password which is assigned by the database administrator. The database administrator identifies legitimate users of the database and assigns each a passwords that they use to directly or indirectly access the database for manipulation, retrieval or updating of the data. The second issue that is concerned with database security is database vulnerabilities. Threats from a variety of sources such as internet and users should be identified and minimized to reduce the chances of the database security being breached. This could be done through use of firewalls to manage the network traffic in the organization and also, through controlled access to the database for the users. Updates and patches to the databas e management system should be routinely done to help enhance the security of the database. The database administrator should be updated on the current trends of security so that he/she can mend the database where such vulnerabilities occur. The third aspect on database security is auditing. ... For instance, in the case of Happy Homes Ltd, applications could be used to record the sales of houses. This and many others are potential sources of database threats as they may leave vulnerabilities in the database. The database administrator should be in a position to determine the permissions of the applications so that he/she can regulate them (Alfred Basta, 2011). Distributed Database Management System This database system connects a variety of databases in various regions over a network and operates in a way that the users are not aware of the distributed databases. In the case of Happy Homes Ltd, the databases could be located in various regions and then have a central server that synchronizes the operations of the whole system. Each region’s database handles information related to that region and when there is need, it shares its resources with other database system s in other regions. A sample diagram for the Happy Homes Ltd could be defined as: In each region, a ser ver helps in the management of the regional system. It also helps in communication among the various regional offices and to the main server. Data is stored in the database at a given region. A backup copy of these data is stored in the main database system at the organization headquarters. Storage of data in these areas helps in easier and quicker access to the data. Centralizing the data in one area reduces the system performance as compared to distributed system. Maintenance and administration of the distributed system is also easy as it can be done as per region. This makes it easier for database administrators since incase repairs are going on in one area other regions are not affected by the repairs. Troubleshooting and handling

An empirical evaluation of the Purchasing Power Parity Dissertation

An empirical evaluation of the Purchasing Power Parity - Dissertation Example In pursuit of investigating the empirical validity of the PPP theory, this study uses the monthly Japanese Yen to US Dollar exchange rate and the seasonally adjusted Japanese and US monthly Consumer Price Index series as the representative of the price levels as available from OECD main economic indicators 2010. Our data set covers a sample period ranging from 1st January1960 to 1st June 2010. The indexing of CPI for both the Japanese and US series is in accordance with assuming the price level of 2005=100.5.  EstimationThis section presents the results of the estimations specified in section 2. We start of by presenting the statistical preliminaries and time series plots of the variables to engender a preconception of what can be expected from the estimated equations. a.  Statistical preliminariesTable 1 presents the summary statistics for the variables of interest. Note that these are expressed in terms of natural logarithms of the levels.Figure 1 below depicts the inter-tempor al dynamics of the natural logarithm of the series of Japanese Yen to US Dollar Exchange rates. Observe that the series provides a clear visual evidence of a downward trend implying that over the period of 1970 to 2011, there has been a gradual decline in the exchange rate. Additionally, the series also appears to be non-stationary. Of course stationarity properties can only be conclusively verified after formal conduction of unit root tests. Figure 3 presents the time plots of Japanese and US consumer price indices in logs.... tion: where is the natural log of the Japanese Yen to US Dollar exchange rate at time t, is the natural log of the price level index of Japan and is the natural log of the price level index of USA and is an additive iid noise term. 3. Testable Hypothesis The hypotheses that we can test using this specification are as follows: i) Strong or absolute PPP: ii) Relatively weaker form of PPP: ? iii) Weakest form of PPP: ? Note that for ii) and iii) to be valid specifications, the additive error term will have to be stationary. Otherwise estimates will be spurious. 4. Data In pursuit of investigating the empirical validity of the PPP theory, this study uses the monthly Japanese Yen to US Dollar exchange rate and the seasonally adjusted Japanese and US monthly Consumer Price Index series as the representative of the price levels as available from OECD main economic indicators 2010. Our data set covers a sample period ranging from 1st January1960 to 1st June 2010. The indexing of CPI for both the Japanese and US series is in accordance with assuming the price level of 2005=100. 5. Estimation This section presents the results of the estimations specified in section 2. We start of by presenting the statistical preliminaries and time series plots of the variables to engender a preconception of what can be expected from the estimated equations. a. Statistical preliminaries Table 1 presents the summary statistics for the variables of interest. Note that these are expressed in terms of natural logarithms of the levels. Table 1: Summary Statistics of the variables of interest Figure 1 below depicts the inter-temporal dynamics of the natural logarithm of the series of Japanese Yen to US Dollar Exchange rates. Observe that the series provides a clear visual evidence of a downward trend