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Iterative MILP Methods for Vehicle Control Problems  [PDF]
Matthew Earl,Raffaello D'Andrea
Computer Science , 2005,
Abstract: Mixed integer linear programming (MILP) is a powerful tool for planning and control problems because of its modeling capability and the availability of good solvers. However, for large models, MILP methods suffer computationally. In this paper, we present iterative MILP algorithms that address this issue. We consider trajectory generation problems with obstacle avoidance requirements and minimum time trajectory generation problems. The algorithms use fewer binary variables than standard MILP methods and require less computational effort.
User office proposal handling and analysis software  [PDF]
Joern Beckmann,Juergen Neuhaus
Physics , 2002,
Abstract: At FRM-II the installation of a user office software is under consideration, supporting tasks like proposal handling, beam time allocation, data handling and report creation. Although there are several software systems in use at major facilities, most of them are not portable to other institutes. In this paper the requirements for a modular and extendable user office software are discussed with focus on security related aspects like how to prevent a denial of service attack on fully automated systems. A suitable way seems to be the creation of a web based application using Apache as webserver, MySQL as database system and PHP as scripting language.
Software for handling and replacement of missing data  [cached]
Mayer, Benjamin,Muche, Rainer,Hohl, Kathrin
GMS Medizinische Informatik, Biometrie und Epidemiologie , 2009,
Abstract: In medical research missing values often arise in the course of a data analysis. This fact constitutes a problem for different reasons, so e.g. standard methods for analyzing data lead to biased estimates and a loss of statistical power due to missing values, since those methods require complete data sets and therefore omit incomplete cases for the analyses. Furthermore missing values imply a certain loss of information for what reason the validity of results of a study with missing values has to be rated less than in a case where all data had been available. For years there are methods for replacement of missing values (Rubin, Schafer) to tackle these problems and solve them in parts. Hence in this article we want to present the existing software to handle and replace missing values on the one hand and give an outline about the available options to get information on the other hand. The methodological aspects of the replacement strategies are delineated just briefly in this article.
Bounded Model Checking of Multi-threaded Software using SMT solvers  [PDF]
Lucas Cordeiro,Bernd Fischer
Computer Science , 2010,
Abstract: The transition from single-core to multi-core processors has made multi-threaded software an important subject in computer aided verification. Here, we describe and evaluate an extension of the ESBMC model checker to support the verification of multi-threaded software with shared variables and locks using bounded model checking (BMC) based on Satisfiability Modulo Theories (SMT). We describe three approaches to model check multi-threaded software and our modelling of the synchronization primitives of the Pthread library. In the lazy approach, we generate all possible interleavings and call the BMC procedure on each of them individually, until we either find a bug, or have systematically explored all interleavings. In the schedule recording approach, we encode all possible interleavings into one single formula and then exploit the high speed of the SMT solvers. In the underapproximation-widening approach, we reduce the state space by abstracting the number of state variables and interleavings from the proofs of unsatisfiability generated by the SMT solvers. In all three approaches, we use partial-order reduction (POR) techniques to reduce the number of interleavings explored. Experiments show that our approaches can analyze larger problems and substantially reduce the verification time compared to state-of-the-art techniques that combine classic POR methods with symbolic algorithms and others that implement the Counter-Example Guided Abstraction Refinement technique.
Solving Linux Upgradeability Problems Using Boolean Optimization
Josep Argelich,Daniel Le Berre,Inês Lynce,Joao Marques-Silva
Electronic Proceedings in Theoretical Computer Science , 2010, DOI: 10.4204/eptcs.29.2
Abstract: Managing the software complexity of package-based systems can be regarded as one of the main challenges in software architectures. Upgrades are required on a short time basis and systems are expected to be reliable and consistent after that. For each package in the system, a set of dependencies and a set of conflicts have to be taken into account. Although this problem is computationally hard to solve, efficient tools are required. In the best scenario, the solutions provided should also be optimal in order to better fulfill users requirements and expectations. This paper describes two different tools, both based on Boolean satisfiability (SAT), for solving Linux upgradeability problems. The problem instances used in the evaluation of these tools were mainly obtained from real environments, and are subject to two different lexicographic optimization criteria. The developed tools can provide optimal solutions for many of the instances, but a few challenges remain. Moreover, it is our understanding that this problem has many similarities with other configuration problems, and therefore the same techniques can be used in other domains.
Exception Handling--An Approach to Improving Software Robustness

JIANG Shu-Juan XU Bao-Wen,

计算机科学 , 2003,
Abstract: Exception handling is a technique that tests and handles exception events. Unlike the traditional methods that usually deal with exceptions at later design and implementation phases and easily result in many problems, we emphasis that sufficient attention should be paid to software exception handling during the development of the software requirements definition. By enforcing this policy through all phases of software development, the level of robustness can be improved considerably. In this paper, the concepts of exception handling are firstly introduced, then the methods of exception handling are discussed, all kinds of exception handling methods and tools are also compared. The current problems and future directions are analyzed at the end of the paper.
Data and Cost handling Techniques for Software Quality Prediction Through Clustering
Saifi Bawahir , Mohsin Sheikh
International Journal of Advanced Computer Research , 2012,
Abstract: Analysis of Data quality is an important issue which has been addressed as data warehousing, data mining and information systems. It has been agreed that poor data quality will impact the quality of results of analyses and that it will therefore impact on decisions made on the basis of these results. An attempt to improve classification accuracy by pre-clustering did not succeed. However, error rates within clusters from training sets were strongly correlated with error rates within the same clusters on the test sets. This phenomenon could perhaps be used to develop confidence levels for predictions. The main and the common problem that the software industry has to face is the maintenance cost of industrial software systems. One of the main reasons for the high cost of maintenance is the inherent difficulty of understanding software systems that are large, complex, inconsistent and integrated. The main reason behind the above phenomena is because of different size and level of arrangements. Decomposing a software system into smaller, more manageable subsystems can aid the process of understanding it signi cantly. Different algorithms construct different decompositions. Therefore, it is important to have methods that evaluate the quality of such automatic decompositions. In our paper we present a brief survey on software quality prediction through clustering.
A systematic approach for structuring exception handling in robust component-based software
Castor Filho, Fernando;Guerra, Paulo Asterio de C.;Pagano, Vinicius Asta;Rubira, Cecília Mary F.;
Journal of the Brazilian Computer Society , 2005, DOI: 10.1590/S0104-65002005000100002
Abstract: abstract component-based development (cbd) is recognized today as the standard paradigm for structuring large software systems. however, the most popular component models and component-based development processes provide little guidance on how to systematically incorporate exception handling into component-based systems. the problem of how to employ language-level exception handling mechanisms to introduce redundancy in componentbased systems is recognized by cbd practitioners as very difficult and often not adequately solved. as a consequence, the implementation of the redundant exceptional behaviour causes a negative impact, instead of a positive one, on system and maintainability. in this paper, we propose an approach for the construction of dependable component-based systems that integrates two complementary strategies: (i) a global exception handling strategy for inter-component composition and (ii) a local exception handling strategy for dealing with errors in reusable components. a case study illustrates the application of our approach to a real software system.
Exception Handling Model Based on Colored Petri Net in Service-oriented Software

WU Qing,YING Shi,JIA Xiang-yang,

计算机科学 , 2011,
Abstract: The workload of exception handling development is heavy, with complex program logic. If how to handle exception is considered just in the late design phase or coding phase, the omitted exceptions can seriously affect the overall reliability of the software. For the features of exception handling in scrviccoricnted software, it presented an exception handling model based on colored Petri net. It provides reusable exception handling model elements, by formally describing the elements of exception handling and exception handling patterns. Designer connects the elements of exception handling using exception handling patterns, which forms a complete exception handling model. The model can accurately describe the overall program of exception handling in service-oriented software,aiding to detect the defects in it.
Information-Control Software for Handling Serial Devices in an EPICS Environment  [PDF]
P. Chevtsov,S. Schaffner
Physics , 2001,
Abstract: Each accelerator control system has a variety of measurement devices. One of the most common types of instrument interfaces used for their control is a serial (RS-232) bus. It is inexpensive and adequate for relatively simple measurement and control devices such as switchers, amplifiers, voltmeters, and steppermotors. Since the RS-232 specification is very broad and does not require uniformity above the basic communication protocol level, one of the major problems associated with the use of RS-232 is that the command protocol for each device is unique. This makes it difficult to design generic drivers for RS-232 and also hampers efforts to design generic troubleshooting methods. This paper presents software developed independently at three other labs and integrated into a single system at Jefferson Lab to handle serial devices in a generic manner. The software is based on the EPICS toolkit and uses a 3-tier architecture including a common serial driver at the bottom, a top-level protocol to specify individual device commands in a generic manner, and a mid-level of software to "glue" the two together.
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