Candidate Set Essay Example for Free

Candidate Set Essay Part of the fast changing science of database management is the improvement of association rules generation. Several algorithms had been proposed and implemented in different platforms or programs to generate these rules. These rules state the rate of confidence of predicting an occurrence of entity or an event based on the occurrence of another entity or event. One popular algorithm proposed to generate the association rules of a given data is the Apriori Algorithm. It uses the bottom-up approach in order to come up with all the significant association rules by specifying the minimum support a super set must have. With the help of a pruning step that uses the property of infrequent set defined in the paper Fast Algorithms for Discovering the Maximum Frequent Set [Lin98], the database scans needed to obtain the MFS are minimized. Another algorithm to solve the maximum frequent sets is the top-down approach. Its first main aim is to discover the Maximum Frequent Candidate Set (MFCS) that would quickly gives all the other frequent set based on the property of frequent sets. Here in this paper, we would compare the disadvantages to be encountered on both algorithms and how the integration of the two cited algorithms would work and be implemented. Apriori Algorithm’s Dilemma FIGURE 2. 1: Lattice 1, 2, and 3 resembling the discovery of frequent set [Dun03]. PROPERTY 1: If an item set is infrequent, all its superset must be infrequent, and they do not need to be examined further. Apriori Algorithm needs to check the entire super sets with one element, {A}, {B}, {C}, and {D}, in order to know the MFCS. With the help of the pruning step that use the above stated property of infrequent sets then in Figure 2. 1 we could determine the MFCS of the universe ABCD by performing Apriori Algorithm. In Figure 2. 1 we should perform four database scans checking the super sets A, B, C and D respectively before we could determine the MFCS for all lattices in Figure 2. 1. Lattice 1 needs four database scans before determining that A is the MFCS. Lattice 2 needs four scans in order to determine ACD and this would be the same in lattice 3 which needs four scans before we would conclude that ABCD is the MFCS. What if we would consider a lattice with 5 items, with 6 items and so on? We would then come up with the conclusion that Apriori Algorithm needs to have n database scans for n items. By considering the above fact, try to examine the lattice of ABCDEFGHIJKLMNOP QRSTUVWXYZ. Then we would conclude that MFCS would be determined after 28 database scans through the use of Apriori Algorithm. The Top-down Approach and the MFCS The top-down approach works well when the MFCS is long. What if the database to be examined has up to 100 items? Then, in Apriori Algorithm, it needs to have 100 database scans in order to come up with the MFCS. On the contrary, the Top-down approach starts with the set containing all the elements of the item set considered down to its subsets. In Figure 2. 1 the Top-down approach checks first the frequency of ABCD, BCD, and so on. What is better with the Top-down Approach compared to the Apriori Algorithm is that it only needs to know the first occurrence of a frequent set to get the MFCS. This is because of the second property of frequent sets. PROPERTY 2: If an item set is frequent, all its subsets must be frequent and they do not need to be examined further. Let’s examine the performance of top-down approach for the three lattices in Figure 2. 1. Top-down approach works best when all of the items in the item set are all frequent. In lattice 3, Top-down approach needs only one database scan in order to come up with the complete frequent sets. Lattice 3’s MFCS is ABCD, therefore it would consider all the subsets of ABCD because ABCD is frequent in the first place. But the problem with the top-down approach is when the MFCS is short. On lattice 3, the number of database scans needed to know MFCS is still lower than the number of database scans needed in the Apriori algorithm, three as compared to four. But on the case of the lattice three, the Top-down approach needs to traverse all the points in the lattice in order to determine the MFCS which is A. The table below gives a view of the database scans needed to determine the complete MFS. Table 2. 1 Apriori and Top-down Approach Comparison Items Apriori Top-down Approach Best case:1 Worst case: 15 5 5 Best case: 1 Worst case: 31 . . . n n Best case: 1 Worst case: 2n 1 Upon considering both the advantages and disadvantages of the two above discussed algorithms, I had decided to merge the good side properties of the two algorithms. To come up with an integrative algorithm that would make use of the concepts of the Apriori Algorithm and Top-down approach, we should first understand or simulate how the two algorithms come up with generating their set of possible candidates for frequent sets. Here is a program code that would generate Apriori Algorithm’s set of possible candidates given the starting candidate {0} and the number of items to be considered. Note that I had opted to start the representation of the possible candidates with zero because the Java program that I had decided to use in order to perform the discussed algorithms uses zero as its start index on its array data structures. Accompanying this program code is the explanation of how did the recursive property come up with the set of possible candidates.

Essay --

â€Å"You Learn Something New Every Day† Bud Blake, ‘Tiger’ (1918-2005) This comical strip of art created by â€Å"the genial cartoonist whose ‘Tiger’ comic strip was adored worldwide† (King Features, 2005) raises many important and striking questions. Although we have a general idea of what learning means, do we know its true definition? Do we understand its significance, its inevitable role in our everyday lives from the moment of birth? The old adage says â€Å"You learn something new every day†. So does that mean that learning is a continuous process? Or does it only happen in a classroom or a lecture room? How does learning happen? Is it a voluntary process or involuntary, conscious or unconscious? However, defining learning and explaining the various learning theories alone, does not provide enough accuracy or truthfulness when applying the theory to third-level students. It is vital to keep in mind who the modern Irish third-level student is as the interpretations may vary. The 21st century presents students of all diffe rent shapes and sizes, with various abilities and backgrounds. This essay will examine theories behind the phenomenon of learning in an attempt to draw up a vivid explanation of what it is, how it works and how it can be applied to a modern Irish third-level student. So what is learning? Well, it can be understood as â€Å"a relatively permanent change in behaviour that is brought about by experience† (Feldman, 2010) or â€Å"just a matter of creating associations among ideas as a direct result of experience† (Gleitman, Gross and Reisberg, 2010). Many other educational psychologists define learning as â€Å"the achievement of greater proficiency, mastery and fluency in a person’s capacity to know or do something that they were previo... .... Clearly, not all behaviour observed is repeated. If a satisfactory reward follows a behaviour, it will be repeated. If there is a punishment for carrying out a behaviour, chances are, it will not reoccur. Observational learning is really common third level education. If a student sees his friend study well, attend all lectures and tutorials and get rewarded with good grades and increased motivation, that student will be encouraged to do the same. Undeniably, no two people are the same. We all differ in one way or another, including in how we learn. We are born with different abilities and brought up in different circumstances through which the values of learning are passed on to us. Therefore, some students are more motivated to succeed than others. For example voluntary immigrant students perform better than those who are involuntary immigrants (Feldman, 2011).

Manifestations of vandalism Essay

Some say that the youths of today are irresponsible. This view merits consideration because it is debatable. Nowadays, vandalism become a trend around the teenagers. According in the Oxford Dictionary vandalism means a destruction by vandals. This vandalism has become a culture for the teenagers. This issue is making a country so ashamed towards the others country. There are many factors, effect and resolution for this issue. We must take a action to reduce this vandalism among the teenagers. Teenagers are the product of a community system. Dysfunctional society will eventually produce a flawed product. Attitude of some people now who cared more about materialistic and indifferent to social issues certainly complicate the existing problem. According to many studies vandalism occurred in the city. Youth scribbling and damaging public property rather than not educated but the generation born in the city is difficult to control. In urban areas some people do not care for what is happening around them. By the youth feel that they are free to pursue this regardless of the negative symptoms of a sense of responsibility towards public property. Vandalism activities also have adverse effects on society. Activity causing vandalism of public property such as public telephones and so destroyed. It will be difficult for the community if they had to use public facilities for emergency purposes. Vandalism is often underestimated by the local community. They just sit back while the vandalism happened in front of their eyes. Finally people also suffer from the heinous activities. Community is difficult to make contact during emergency situations. Example public phones damaged during house is on fire. In addition, the community is not comfortable while using other public property. Example wet while waiting for the bus because the bus stop damaged roof could not stop because of the rain. Graffiti on the walls of public toilets worsen and encourage the younger generation to emulate these unhealthy symptoms. In addition, vandalism activities also affect the country. Vandalism activities cause and affect the country’s image tarnished Malaysia’s economic position. This is due to the lack of the arrival of tourists from outside to Malaysia because of the bad environment and attitudes of the  people who do not care. In effect, the country’s tourism industry will decline. Industries in tourism is among the contributors to the country’s economic position. Decline in tourism caused by losses due to unemployed people had to repair and improve infrastructure and public facilities have been destroyed. Read more:  Causes of Vandalism Essay Many vandalism phenomena that can affect the eye can see and this certainly affects the image of the country. Total losses due to this vandalism is enormous. Allocation of funds used for refurbishing and repairing damaged facilities is better if used for other projects that are more beneficial. This course will benefit the nation as a whole. There are many factors of being this vandalism among the teenagers. The first factors is peer influence. Peer influence can lead to vandalism. Teenagers usually easier to copy and influence by their peers. Peer influence will shape the attitudes, values and behaviours among the youth, especially youth who have dropped out and family problem. Usually, teenagers who commit vandalism is a teenager in the group, they do not have a purpose and when gathered arise include scribbling ideas and damaging public property. Peer influence also make the teenagers become incautious about their studies and not focus about their education. Moreover, parenting and family also one of the factors of being the vandalism among the teenagers. Parents are the impetus for the nature of vandalism among teenagers. For example, when driving parents littering or skin of fruits such as rambutan and oranges while ignoring the speed limit signs. Some teenagers who get caught in symptom vandalism comes from troubled families or families that practice negative life. According to a study carried out revenge vandalism by teenagers who want to be free and a troubled family background. Besides lack of proper control and guidance of parents also among the main factor influence youth stuck in negative symptoms. Therefore, the measures to overcome the problem of vandalism among teenagers should be implemented immediately.First of all, parents should carry out an important role in cleaning up the vandalism. They need to monitor the activities of their children so as not slipping into the negative. Not only that, but mixing children should also be monitored in order to not make a mistake in choosing a partner. Moreover, parents should inculcate in themselves divinity children since childhood. This is so because of religious knowledge can become a major fortification in preventing young people from influenced by negative elements like  vanadalisme activities. If parents fulfill their roles properly, definitely vandalism can be easily overcome. Furthermore, role of society and the school should have to help this issue to reduce the vandalism among the teenagers. Every member of society should be concerned about and pay attention to their children not to do this wrong, and people should be aware of what is happening around them. Community needs to be proactive against vandalism symptoms that occur in their area. In addition members of the community can play a vital role to provide an understanding of how bad moral vandalism. The school should provide advice and guidance to students about the importance of public property. Younger generation should be explained in detail about their responsibility for public property. Explain to students what their feelings if their school bags defaced or torn by irresponsible people such awareness will partly reflect the importance of attitude and responsibility. Therefore, all parties, particularly the parents, the community, the government and schools should work together and carry out their obligations in order to reduce the symptoms of this increasingly serious. If the intention is successfully implemented, it is possible our country can stand, sit low in developed countries. Hopefully, with this solution, we are able to realize the Vision 2020 and is famous the world over.

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