Particle detector calibration and performance for Horizon-T cosmic rays experiment

Due to large variation of particle density in EAS, a response linearity of each detector needs to be assessed. The number of photon in a photo multiplier tube (PMT) pulse allows inferring the deviation from linearity in each case. In order to obtain an approximate photon count of a pulse, a single photo-electron response pulse calibration for the R7723 PMT was conducted using low-level light pulse. Non-linearity measurements of PMT were conducted using the same setup. PMT signals were chosen such that their widths are comparable with the real data. Results included in this work show that the PMT signal is mostly linear and nonlinearity starts only at the upper end of ADC range

Stepwise refinement of heap-manipulating code in Chalice

Stepwise refinement is a well-studied technique for developing a program from an abstract description to a concrete implementation. This paper describes a system with automated tool support for refinement, powered by a state-of-the-art verification engine that uses an SMT solver. Unlike previous refinement systems, users of the presented system interact only via declarations in the programming language. Another aspect of the system is that it accounts for dynamically allocated objects in the heap, so that data representations in an abstract program can be refined into ones that use more objects. Finally, the system uses a language with familiar imperative features, including sequential composition, loops, and recursive calls, offers a syntax with skeletons for describing program changes between refinements, and provides a mechanism for supplying witnesses when refining non-deterministic programs

Data-driven synthesis for object-oriented frameworks

Software construction today often involves the use of large frameworks. The challenge in this type of programming is that object-oriented frameworks tend to grow exceedingly intricate; they spread functionality among numerous classes, and any use of the framework requires knowledge of many interacting components. We present a system named MATCHMAKER that from a simple query synthesizes code that interacts with the framework. The query consists of names of two framework classes, and our system produces code enabling interaction between them. MATCHMAKER relies on a database of dynamic program traces called DELIGHT that uses novel abstraction-based indexing techniques to answer queries about the evolution of heap connectivity in a matter of seconds. The paper evaluates the performance and effectiveness of MATCHMAKER on a number of benchmarks from the Eclipse framework. The paper also presents the results of a user study that showed a 49% average productivity improvement from the use of our tool.National Science Foundation (U.S.). (Grant number CCF-1049406)Massachusetts Institute of Technology. Computer Science and Artificial Intelligence Laborator

Unifying Execution of Imperative and Declarative Code

We present a unified environment for running declarative specifications in the context of an imperative object-Oriented programming language. Specifications are Alloy-like, written in first-order relational logic with transitive closure, and the imperative language is Java. By being able to mix imperative code with executable declarative specifications, the user can easily express constraint problems in place, i.e., in terms of the existing data structures and objects on the heap. After a solution is found, the heap is updated to reflect the solution, so the user can continue to manipulate the program heap in the usual imperative way. We show that this approach is not only convenient, but, for certain problems can also outperform a standard imperative implementation. We also present an optimization technique that allowed us to run our tool on heaps with almost 2000 objects