Daniel J. Buehrer

A shape recognition scheme based on relative distances of feature points from the centroid

Abstract In this paper, a simple but efficient scheme to recognize shapes is proposed. In our scheme, all of the boundary points are used to calculate the centroid of an object, then the distance between each feature point and the centroid is computed. We have shown that the time complexity of our shape matching algorithm is O(m), where m is the number of feature points. The most important advantage of our method is its independence to translation, rotation and scaling of objects.

Access control in a hierarchy using a one-way trap door function

Abstract Often a security system groups users into a hierarchy, with user classes on top having access to objects of user classes below them. Previously proposed cryptographic schemes [1–6] assign a key to each user class. Any user can compute from his key the keys of all user classes who are below him in the hierarchy, thus giving him their access privileges. Moreover, these schemes prevent the possibility of users collaborating to compute a key to which they are not entitled. The major disadvantage of the proposed schemes is that it is not easy to add a new user without having to change most of the previously defined keys. The other major disadvantage is the amount of storage it takes to store the keys. In this paper, we overcome these problems whenever the number of user classes is large and the hierarchical structure is non-skewed. The proposed algorithm, inspired by a remarkable concept invented by S.J. MacKinnon [5], also permits a user to access all files of users who are below him in the class hierarchy. It makes it easy, however, to add new user keys without affecting most of the previously-assigned keys.

A Ring-Based Decentralized Collaborative Non-blocking Atomic Commit Protocol

Many asynchronous distributed atomic commit protocols use a coordinator, either an application server or an elected database server, to handle the progress of a transaction. When the coordinator fails or the network becomes partitioned, the transaction may block or may suffer from a split brain syndrome. In this paper we propose a decentralized, collaborative, non-blocking atomic protocol, which piggybacks transaction statuses of all transaction participants onto tokens, and passes the tokens in a logical ring with two distinct directions. Each participant uses the information in the tokens to make a decision of when to go to the next state. Using the state vectors in the tokens, the transaction can progress even if the network is partitioned, and the protocol will ensure uniform agreement on success or failure of the transaction.

Using quad smoothness to efficiently control capacity-distortion of reversible data hiding

One of the main uses of data hiding is to protect secret messages being transmitted on the Internet. Reversible data hiding can fully recover the original host image after extracting the secret message. It is especially suitable for applications where, after extracting the secret message, the quality of the recovered host image cannot be compromised, such as for medical or military image data. Many difference-expansion-based (DE-based) reversible data hiding methods have made use of a threshold value to control the stego-images quality. Usually repeated trial and error is required to find a relatively good threshold with acceptable capacity-distortion behavior. This paper introduces a scheme that does not require a threshold value, such as is used in Alattars quad-based reversible data hiding. It applies a prediction of quad of quads smoothness to determine the embedding sequence. The proposed scheme is shown to perform better than other DE-based schemes. Results showed that it has the ability of maintaining embedding quality at all capacity levels, especially when the embedding capacity is at low to medium levels.

From interval probability theory to computable fuzzy first-order logic and beyond

This paper first presents a simple explanation for the min/max bounds which are used in interval probability theory (IPT), possibility theory, fuzzy rough sets, and vague logic. Based on this definition, a computable version of first-order fuzzy logic is defined, where all of the upper bounds for instances of a theorem and its negation are guaranteed to eventually be listed. Based on this fuzzy logic, a complete version of fuzzy Prolog is defined. This fuzzy Prolog is then used to give some examples of fuzzy Prolog definitions of fuzzy concepts such as fuzzy linguistic variables, fuzzy modifiers, fuzzy quantifiers, and various kinds of fuzzy norms and conorms.<<ETX>>

CA-ABAC: Class Algebra Attribute-Based Access Control

We propose a trust framework model for an educational cloud which is designed to overcome inequalities of M-shaped incomes by simplifying contract-based sharing of resources among multiple schools. We use class algebra, which is similar to SROIQ(D) description logic, as the access control policy language. Benefiting from the high expressivity of class algebra, our model can use implicit relations and reasoning to enforce access control that corresponds to the contracts. The security mechanism allows one-time user login to obtain all of this userâs credentials for accessing services. In addition, our model can select appropriate material to adapt to the level of the student by adding the classification information to the attributes of the educational material and the student, and integrating this information into the access control policy to build an exclusive learning graph for each student.

An evaluation of TDD training methods in a programming curriculum

This paper evaluates an innovative training method which is based on TDD (test driven development) [4] and implemented in an automatic online judge system named DICE [9]. After running the automatic grading system DICE at Hsin Kuo High School in Taiwan for years, we found that some students were left out by the DICE system. We needed a more sophisticated mechanism to assist under achievers. Our solution was to utilize TDD as an extension of the DICE system to promote learning performance in programming. We implemented DICE with TDD and have applied the innovative training method in the programming curriculum at Hsin Kuo High School in Taiwan for one semester. Simultaneously we conducted an experiment with a control and experimental group to estimate the efficiency of DICE with TDD. Our finding is that DICE with TDD improves the mean scores of learners by 50.88% over the control group.

A TWO-DIMENSIONAL SHAPE RECOGNITION SCHEME BASED ON PRINCIPAL COMPONENT ANALYSIS

In this paper, we propose a simple, but efficient method to recognize two-dimensional shapes without regard to their translation, rotation, and scaling factors. In our scheme, we use all of the boundary points to calculate the first principal component, which is the first shape feature. Next, by dividing the boundary points into groups by projecting them onto the first principal component, each shape is partitioned into several blocks. These blocks are processed separately to produce the remaining shape features. In shape matching, we compare two shapes by calculating the difference between the two sets of features to see whether the two shapes are similar or not. The amount of storage used to represent a shape in our method is fixed, unlike most other shape recognition schemes. The time complexity of our shape matching algorithm is also O(n), where n is the number of blocks. Therefore, the matching algorithm takes little computation time, and is independent of translation, rotation, and scaling of shapes.

The Cadabia Persistent Storage Service

This paper describes the advantages of Cadabiaover competing network programming frameworks.Cadabia is a middleware service architecture for sharing dynamic classes and objects in network-based applications. A default database editor can either be run as a stand-alone RMI application or as a Web service. Cadabia queries can be used as properties of GUI components to read/update persistent data.Cadabia is freeware, and contributions tosourceforge.org/ projects/Cadabia are welcomed.

Using a Class Algebra Ontology To Define Conversions between OWL/SQL/Java Beans

This paper describes the xml definition of class algebra which is available at http://xbean.cs.ccu.edu.tw/~dan/classAlgebra.xml . A sample user-defined ontology document and instance document are available at http://xbean.cs.ccu.edu.tw/~dan/userOntology.xml and http://xbean.cs.ccu.edu.tw/~dan/userInstances.xml . The class algebra ontology is very similar to the OWL ontology, but it uses its own definition of pointers for non-partOf relations. This simplifies the underlying theory as well as the syntax. The same syntax is used to define the ontology (i.e. the schema) as well as instance documents. The class algebra ontology has sufficient information to enable conversion between class algebra instance documents, SQL tables, and Java persistent objects, all of which can be queried by class algebra queries and updated by class algebra assignment operators, RMI calls, or SOAP method calls. The state-space graph of all possible orderings of class algebra operators is searchable by efficient constraint-based search techniques. Operators include guarded class algebra assignments as well as traditional SOAP or RMI method calls.