Agricultural Extension services are among the most important rural services in developing countries. The services are considered to be a key driver of technological change and productivity growth in agriculture. In Kenya, like in the rest of the developing economies, agricultural extension has largely been delivered through supply–driven approaches. Due to perceived low impact of agricultural e...

Exhaustive global array data flow analysis for communication optimization is expensive and considered to be impractical for large programs. This paper proposes a demand-driven analysis approach that reduces the analysis cost by computing only the data flow information related to optimizations. In addition, the analysis cost of our scheme can be effectively managed by trading space for time or c...

In this paper, an implementation of a demand-driven alias analysis [7] in Open64 is presented. In the algorithm, a program expression graph is constructed based on all the expressions and assignments in the program, and the memory alias problem is formulated as a CFL-reachability problem. To deal with field accesses of structs which are common in multi-media applications, a field-sensitive exte...

Information requirements analysis for data warehouse systems differs significantly from requirements analysis for conventional information systems. Existing data warehouse specific approaches are reviewed. A comprehensive methodology that supports the entire process of determining information requirements of data warehouse users, matching information requirements with actual information supply,...

This thesis develops a demand driven solver for constraint based control flow analysis. Our approach is modular, flow-sensitive and scaling. It allows to efficiently construct the interprocedural control flow graph (ICFG) for object-oriented languages. The analysis is based on the formal semantics of a Java-like language. It is proven to be correct with respect to this semantics. The base algor...

Dynamic code obfuscation technique increases the difficulty of dynamically reverse by the runtime confusion. Path explosion directly affects the efficiency and accuracy of dynamic symbolic analysis. Because of the defect, this paper presents a novel algorithm DDD (Demand-Driven Dynamic Obfuscation Algorithm) by using the demand-driven theory of symbolic analysis. First, create a large number of...

We present a new static type analysis for dynamically-typed languages that produces high quality results at a cost that remains practicable. The analysis has the ability to adapt to the needs of the optimiser and to the characteristics of the program at hand. The result is an analyser that quickly transforms itself to be better equipped to attack the program. Experiments show that our approach ...

Algorithm recognition is an important problem in program analysis, optimization, and more particularly program comprehension. Basically, one would like to submit a piece of code, and get an answer like “Lines 10 to 23 are an implementation of Gauss-Jordan elimination”. Existing approaches often perform a bottom-up recognition, using a database describing many implementation variations of a give...

In this work we present a modular and demand-driven analysis of the semantic difference between program versions. Our analysis characterizes initial states for which final states in the program versions differ. It also characterizes states for which the final states are identical. Such characterizations are useful for regression verification, for revealing security vulnerabilities and for ident...

Many complex analysis problems can be most clearly and easily specified as logic rules and queries, where rules specify how given facts can be combined to infer new facts, and queries select facts of interest to the analysis problem at hand. However, it has been extremely challenging to obtain efficient implementations from logic rules and to understand their time and space complexities, especi...