User:Huzilucky

Personal Information

 * Name: ZI HU
 * Identity: First year PHD Student
 * Email: zihu at usc dot edu

Research Interests

 * Internet Topology
 * Network Security

2010 FALL

 * 1) CSCI 530 Security System
 * 2) CSCI 585 Database System
 * 3) CSCI 597 PHD Seminar

CSCI 530 (Security System)

 * 1) Kerberos
 * 2) An authentication service for computer network(including confidentiality and authorization)
 * 3) Encryption(DES) and the checksum provides integrity and confidentiality for encrypted Kerberos messages
 * 4) Limitations:
 * 5) * Password guessing attack(if user choose a weak password)
 * 6) * Kerberos requires a trusted path through which passwords are entered
 * 7) * Kerberos must be integrated with other parts of the system(it only protects the messages from software that has been written or modified to use it)
 * 8) * Kerberos does not itself provide authorization

CSCI 585 (Database System)

 * 1) Similarity:
 * 2) The ontology and conceptual schema are both on the conceptual level. they both try to represent the entity as well as the relationship between entities in the real world, that is to model a certain domain of the real world by using certain structure which helps to show the information of the domain in a more abstract and structured way.
 * 3) They both use "class" to describe a set of entities which have some attributes in common. Both of them try to arrange the classes in a taxonomic (subclass–superclass) hierarchy according to the requirements in order to reflect some specific properties of the entity as well as the relationship between them.
 * 4) They both use the attributes or slots(in ontology) to describe various features of the entity and also some restrictions on these attributes. Both of them reflect only a certain domain of the real world.
 * 5) To sum up, both ontology and conceptual schema are using some ways to model our real world and to represent the concepts, the relationships and the semantics as much as possible.
 * 6) Differences:
 * 7) The objective is different: the main objective of ontology is to describe the entities or the facts in real world,  to define a set of data and their structure for other programs to use. Problem-solving methods, domain-independent applications, and software agents use ontologies and knowledge bases built from ontologies as data.While conceptual schema mainly focus on relating the general ontological classes(entities in real world), whose objective is measuring and classifying of the observed facts.
 * 8) Different objects: Computational ontologies focus on the real world, on the reality, but not on what can be represented. Conceptual schemas acts as links, connecting the ontologies with facts. Accordingly, the object of a conceptual schema is the relationship between ontological categories and the permissible range of variation among the facts that must be brought into relation with those categories.
 * 9) Common/specific: Ontology try to define a common vocabulary or understanding of the structure of some facts in a certain domain which can be shared by people or software agents, and people can also reuse the ontology definition in the same domain.  Conceptual schema is a map of concepts and relationships which people can use to describe the facts and their relationship in real world and it only focuses on some specific applications, but not a common understanding.