An on-line repository for embedded software

Abstract The use of off-the-shelf components (COTS) can significantly reduce the time and cost of developing largescale software systems. However, there are some difficult problems with the component-based approach. First, the developers have to be able to effectively retrieve components. This requires the developers to have an extensive knowledge of available components and how to retrieve them. After identifying the components, the developers also face a steep learning curve to master the use of these components. We are developing an On-line Repository for Embedded Software (ORES) to facilitate component management and retrieval. In this paper, we address the issues of designing software repository systems to assist users in obtaining appropriate components and learning to understand and use the components efficiently. We use an ontology to construct an abstract view of the organization of the components in ORES. The ontology structure facilitates repository browsing and effective sea rch. We also develop a set of tools to assist with component comprehension, including a tutorial manager and a component explorer

Integrating Clustering and Regression for Workload Estimation in the Cloud

Workload prediction has been widely researched in the literature. However, existing techniques are per‐job based and useful for service‐like tasks whose workloads exhibit seasonality and trend. But cloud jobs have many different workload patterns and some do not exhibit recurring workload patterns. We consider job‐pool‐based workload estimation, which analyzes the characteristics of existing tasks' workloads to estimate the currently running tasks' workload. First cluster existing tasks based on their workloads. For a new task J, collect the initial workload of J and determine which cluster J may belong to, then use the cluster's characteristics to estimate J′s workload. Based on the Google dataset, the algorithm is experimentally evaluated and its effectiveness is confirmed. However, the workload patterns of some tasks do have seasonality and trend, and conventional per‐job‐based regression methods may yield better workload prediction results. Also, in some cases, some new tasks may not follow the workload patterns of existing tasks in the pool. Thus, develop an integrated scheme which combines clustering and regression and utilize the best of them for workload prediction. Experimental study shows that the combined approach can further improve the accuracy of workload prediction

Toward Dependable Safety-Critical Software

The failure of safety-critical systems can result in catastrophic loss of life and property. Hence, it is necessary to assure the reliability of these systems to a high degree of confidence before they are put into operational use. However, at these extreme levels of ultra-high reliability requirements, typically failures rates of less than 10 \Gamma7 failures per hour, errors in the specification and in estimates of the operational profile become significant factors. An approach that has been suggested in practice is to use secondary and tertiary software that meet ultra-high reliability requirements but at a reduced functionality as compared with the primary software. Two major problems are (a) how to select appropriate functionality for the non-primary versions and (b) how to determine when to invoke these backup versions. In this paper, we present a unified approach for handling these two problems. It starts with a rigorous method for assessing ultra-high reliability requirements..

Personnel IS-Effort Collection in Industrial Environments

Spitta T. Personnel IS-Effort Collection in Industrial Environments. In: Belli F, Bastani F, Endres A, eds. 9th International Symposium on Software Reliability Engineering (ISSRE). IEEE; 1998: 111-120.The knowledge of development and maintenance effort is a necessary precondition for all types of software management, IS-controlling, guidance of quality and effort estimation. Data collecting systems seem to be widely used, but the data is said to be unsafe and firm-specific. This paper presents a concept for the collection of personnel effort and for events (e.g. faults). The revised informal specification of this paper is based on experience with such a system used by 40 developers in five locations for many years. Design and practical use of a system based on that concept allow the collection of statistically valid effort data. This would only be possible if developers are sure to be not supervised by their data, and if they don’t need to decide upon classifications during data-entry time. Examples show applications of the data for project management, quality control and IS resource management reporting from 6« years with overall 170 PYs

Impact of Program Transformation on Software Reliability Assessment

The statistical sampling method is a theoretically sound approach for measuring the reliability of safety-critical software, such as control systems for nuclear power plants, aircrafts, space vehicles, etc. It has, however, some practical drawbacks, two of which are the large number of test cases needed to attain a reasonable confidence in the reliability estimate and the sensitivity of the reliability estimate to variations in the operational profile. One way of dealing with both of these issues is to combine statistical sampling with formal methods and attempt to verify complete program paths. This combination becomes especially effective if high usage paths are verified. However, the verification of complete paths is difficult to perform in practice and viable only when there is a high confidence in the correctness of the specification. In this paper we identify program transformations and partial proofs which have a measurable impact on the reliability assessment procedure. These m..