18707877
An efficient debugging method for message-based parallel programs using static analysis information
Guaranteeing reproducibility and minimizing probe effects are major issues in the parallel program debugging. The paper suggests a new debugging method, called the Detect and Reproduce method, for message-based parallel programs. The proposed method is designed to guarantee the reproducible behaviors of a target program and to alleviate probe effects by reducing both the number of the probes to be inserted into a program and the amount of information gathered by those probes. The proposed method achieves such effects by employing a static analysis technique to detect nondeterminacy. By detecting nondeterminacy before running the program, only a small number of probes are required to assure reproducibility. To analyze message-based programs statically, an MHB (minimal happened before) model is designed to catch the synchronization structures and algorithms have been developed to locate nondeterminacy based on the MHB model. Utilizing the analysis results, probes are inserted only into the places where nondeterminacy is likely to take place.
42278030
Hybrid knowledge-based architecture for building an intelligent nondestructive signal inspection system
The paper deals with the methods of implementing an intelligent inspection system for monitoring the health of any device or material using a nondestructive signal. A hybrid knowledge representation and processing architecture is proposed as a solution to problems encountered in the processes of the nondestructive inspection. In the proposed system, to modularize knowledge elicitation and to make knowledge processing reliable, the task of inspection is delegated to two subsystems each of which has a proper knowledge processing scheme to match the properties of its own task. The front-end subsystem which detects the signal patterns (events) for any harmful flaw is built by integrating a fuzzified syntactic pattern recognition concept and a neural network concept. The back-end subsystem which evaluates the characteristics of the events is based upon object-oriented rule base system concepts. The methods of integrating the approaches in the proposed architecture are also proposed in the paper. The proposed architecture is verified by developing and evaluating a prototype which automatically interprets eddy current Lissajous signals to inspect the state of tubes used in nuclear power plants.
31388642
Modeling and Testing Agent Systems Based on Statecharts
This paper presents a testing method for an agent system against its specification described with Statecharts. Here, an agent system means an implementation of an agent application. Its testing method generates test sequences from the specification and checks whether the agent system behaves in accordance with the specification by executing the test sequences. For specification-based testing, we have extended Statecharts in order to describe the behavior of an agent system according to the concept of Agent UML. Then, we propose an approach to generating test sequences from the extended Statecharts. Our approach makes effective use of partial order methods for considering representative sequences of equivalent classes divided from all possible sequences. Therefore, we can efficiently manage a large number of possible sequences caused by the agents’ autonomy. As a result, we can reduce the number of test sequences and the number of executions to be tested.
9037240
Empirical evaluation of a fuzzy logic-based software quality prediction model
Software inspection, due to its repeated success on industrial applications, has now become an industry standard practice. Recently, researchers began analyzing inspection data to obtain insights on how software processes can be improved. For example, project managers need to identify potentially error-prone software components so that limited project resource may be optimally allocated. This paper proposes an automated and fuzzy logic-based approach to satisfy such a need. Fuzzy logic offers significant advantages over other approaches due to its ability to naturally represent qualitative aspect of inspection data and apply flexible inference rules. In order to empirically evaluate the effectiveness of our approach, we have analyzed published inspection data and the ones collected from two separate inspection experiments which we had conducted. χ2 analysis is applied to statistically demonstrate validity of the proposed quality prediction model.
16141068
Improving cohesion metrics for classes by considering dependent instance variables
The existing cohesion metrics for classes do not consider the characteristics of dependent instance variables that are commonly used in a class and, thus, do not properly reflect the cohesiveness of the class. This paper presents an approach for improving the cohesion metrics by considering the characteristics of the dependent instance variables in an object-oriented program.
12216769
Change impact analysis for a class hierarchy
Modified programs are required to be retested to determine whether changes have been made correctly and to investigate whether those cause any adverse effect on the program behavior. Then, the key issue is the extent of the retesting tasks. To save time and efforts, retesting should be done on only the parts that might be affected by changes. Change impact analysis is the activity which identifies the parts to be retested. Object-oriented paradigm is based on several concepts such as encapsulation, inheritance, polymorphism, and dynamic binding. Although these features contribute to the reusability and extensibility of systems, they produce complex dependencies between classes and attributes, which make it difficult to identify the affected components by changes. We propose an approach for analyzing change impact in a class hierarchy. Our approach is based on the class firewall method, but aims to reduce the retesting effort significantly by taking a member function as a test unit. We deal with the impacts of changes associated with various object-oriented features as well as types of changes which can occur at the level of a data member a member function, a class, and an inheritance relation.
5100963
Scalable Modeling and Performance Evaluation of Wireless Sensor Networks
A notable features of many proposed Wireless Sensor Networks (WSNs) deployments is their scale: hundreds to thousands of nodes linked together. In such systems, modeling the state of the entire system as a cross-product of the states of individual nodes results in the well-known state explosion problem. Instead, we represent the system state by the probability distribution on the state of each node. In other words, the system state represents the probability that a randomly picked node is in a certain state. Although such statistical abstraction of the global state loses some information, it is nevertheless useful in determining many performance metrics of systems that exhibit Markov behavior. We have previously developed a method for specifying the performance metrics of such systems in a probabilistic temporal logic called iLTL and for evaluating the behavior through a novel method for model checking iLTL properties. In this paper, we describe a method for estimating the probabilities in a Discrete Time Markov Chain (DTMC) model of a large-scale system. We also provide a statistical test so that we can reject estimated DTMCs if the actual system does not have Markov behavior. We describe results of experiments applying our method toWSNs in an experimental test-bed, as well as using simulations. The results of our experiments suggest that our model estimation and model checking method provides a systematic, precise and easy way of evaluating performance metrics of some large-scale WSNs.
15346879
A 3-D FPGA wire resource prediction model validated using a 3-D placement and routing tool
The interconnection architecture of FPGAs such as switches dominates performance of FPGAs. Three-dimensional integration of FPGAs overcomes interconnect limitations by allowing instances to be located and signals to be routed in 3-D space. Wire resource prediction is important for fast and accurate interconnection planning in 3-D FPGA. In this paper, we extend the existing analytic model shown in [13] with a new parameter for our 3-D FPGA which has cluster-based logic blocks. The proposed wire resource prediction model is applied to our 3-D FPGA using a Xilinx Virtex2 slice [18] and our 3-D routing architecture. We validate the effectiveness of the extended model by comparing the required number of channel wires predicted by the extended analytic equation with that of the placed and routed results using 3-D placement and routing algorithm designed for our 3-D FPGA for a number of benchmark circuits. The extended 3-D wire resource prediction model predicts the required channel capacity with an average of 11.1% error for 17 large circuits from LGSynth93 and ISPD2001 Verilog benchmarks.
19995952
ATOMi: an algorithm for circuit partitioning into multiple FPGAs using time-multiplexed, off-chip, multicasting interconnection architecture
Logic emulation is so far the fastest method to verify the system functionality in the gate level before chip fabrication. Field-programmable gate array (FPGA)-based logic emulator with large gate capacity generally comprises a large number of FPGAs or special processors connected in mesh or crossbar topology. However, gate utilization of FPGAs and speed of emulation are limited by the number of signal pins among FPGAs and the interconnection architecture of the logic emulator. This paper first describes a new interconnection architecture called TOMi (Time-multiplexed, Off-chip, Multicasting interconnection) and proposes a circuit partitioning algorithm called ATOMi (Algorithm for TOMi) for multi-FPGA system incorporating four to eight FPGAs where FPGAs are interconnected through TOMi. ATOMi reduces the number of off-chip signal transfers to optimize the performance for multi-FPGA system implemented by TOMi. Experimental results using Partitioning93 benchmarks show that, by adopting the proposed TOMi interconnection architecture along with ATOMi, the pin count is reduced to 14.4%-88.6% while the critical path delay is reduced to 66.1%-90.1% compared to traditional architectures including mesh, crossbar, and VirtualWire architecture.
13416160
Bandwidth tracing arbitration algorithm for mixed-clock SoC with dynamic priority adaptation
As the processing capabilities and operating frequency of embedded system are growing, so is the needed data bandwidth to fully utilize the processing capability. The ability to transfer huge amount of data between the embedded core and external devices is required for efficient system operation. In this paper, the data communication architecture for the mixed-clock system is proposed. The dynamic priority adaptation algorithm for bus arbitration is proposed for bandwidth guarantee. The communication architecture that incorporates the proposed arbitration algorithm adapts the priority of communication components dynamically based on the information from FIFO. The experiments show that the measured bandwidth of each component traces the required bandwidth well compared to the other arbitration algorithms.
2254400
iLTLchecker: a probabilistic model checker for multiple DTMCs
iLTL is a probabilistic temporal logic that can specify properties of multiple discrete time Markov chains (DTMCs). In this paper, we describe two related tools: MarkovEstimator a tool to estimate a Markov transition matrix, and iLTLChecker, a tool to model check iLTL properties of DTMCs. These tools work together to verify iLTL properties of DTMCs.