Evaluating improvements to a meta-heuristic search for constrained interaction testing

Combinatorial interaction testing (CIT) is a cost-effective sampling technique for discovering interaction faults in highly-configurable systems. Constrained CIT extends the technique to situations where some features cannot coexist in a configuration, and is therefore more applicable to real-world software. Recent work on greedy algorithms to build CIT samples now efficiently supports these feature constraints. But when testing a single system configuration is expensive, greedy techniques perform worse than meta-heuristic algorithms, because greedy algorithms generally need larger samples to exercise the same set of interactions. On the other hand, current meta-heuristic algorithms have long run times when feature constraints are present. Neither class of algorithm is suitable when both constraints and the cost of testing configurations are important factors. Therefore, we reformulate one meta-heuristic search algorithm for constructing CIT samples, simulated annealing, to more efficiently incorporate constraints. We identify a set of algorithmic changes and experiment with our modifications on 35 realistic constrained problems and on a set of unconstrained problems from the literature to isolate the factors that improve performance. Our evaluation determines that the optimizations reduce run time by a factor of 90 and accomplish the same coverage objectives with even fewer system configurations. Furthermore, the new version compares favorably with greedy algorithms on real-world problems, and, though our modifications were aimed at constrained problems, it shows similar advantages when feature constraints are absent.     

Directed test suite augmentation: an empirical investigation

Test suite augmentation techniques are used in regression testing to identify code elements in a modified program that are not adequately tested and to generate test cases to cover those elements. A defining feature of test suite augmentation techniques is the potential for reusing existing regression test suites. Our preliminary work suggests that several factors influence the efficiency and effectiveness of augmentation techniques that perform such reuse. These include the order in which target code elements are considered while generating test cases, the manner in which existing regression test cases and newly generated test cases are used, and the algorithm used to generate test cases. In this work, we present the results of two empirical studies examining these factors, considering two test case generation algorithms (concolic and genetic). The results of our studies show that the primary factor affecting augmentation using these approaches is the test case generation algorithm utilized; this affects both cost and effectiveness. The manner in which existing and newly generated test cases are utilized also has a substantial effect on efficiency and in some cases a substantial effect on effectiveness. The order in which target code elements are considered turns out to have relatively few effects when using concolic test case generation but in some cases influences the efficiency of genetic test case generation. The results of our first study, on four relatively small programs using a large number of test suites, are supported by our second study of a much larger program available in multiple versions. Together, the studies reveal a potential opportunity for creating a more cost‐effective hybrid augmentation approach leveraging both concolic and genetic test case generation techniques, while appropriately utilizing our understanding of the factors that affect them. Copyright © 2014 John Wiley & Sons, Ltd.     

Referenzprozessabläufe für Telekommunikationsunternehmen

The telecommunication market is experiencing substantial changes. New business models, innovative services, and technologies require reengineering, transformation, and process standardization. Enterprise Architecture Frameworks support the transformation by specifying methods, procedures, and reference models. With the Enhanced Telecom Operation Map (eTOM), the TM Forum offers an international de facto reference process framework, based on specific features and requirements of the telecommunication industry. However, this reference framework only offers a hierarchical collection of processes on different levels of abstraction; a control view in terms of a sequential ordering of tasks and hence a real process flow as well as an end-to-end view on the customer are missing. In this paper, we extend the eTOM reference model by reference process flows, in which we abstract and generalize the knowledge about processes in telecommunication companies. With reference process flows, we aim to assist companies in achieving a structured and transparent re-structuring and re-design of their processes. We demonstrate the applicability and usefulness of our reference process flows in two case studies, and evaluate them by means of criteria for reference model evaluation. Our reference process flows have been accepted as a standard by the TM Forum and published as part of eTOM version 9. We further elaborate on those components of our approach which can be applied outside the telecommunication industry.     

On the training and testing of entry-level commercial motor vehicle drivers

This study examined the effectiveness of 3 different training types on commercial motor vehicle (CMV) drivers’ skill levels. The training types included a conventional 8-week certified course, a conventional 8-week certified course with approximately 60% of driving time spent in a CMV driving simulator, and a Commercial Driver's License (CDL) test focused short course. Participants’ scores on the Division of Motor Vehicles (DMV) road and range tests were assessed. In addition to their DMV scores, participants replicated DMV road and range driving tests in an instrumented vehicle and the CMV driving simulator. Results indicated no training group differences in DMV road tests. There were differences between training groups on DMV range tests and real truck and simulator versions of the DMV road and range tests; on these tests conventional- and simulator-trained participants generally scored higher than CDL-focused participants. However, all groups performed higher in the real truck than in the simulator for both road and range tests. These findings indicate the need for a minimum standard of entry-level CMV driver training as well as support of the use of a driving simulator for training entry-level drivers; however, testing using a simulator does not appear to be feasible with current technology.     

l‐Citrulline Supplementation‐Increased Skeletal Muscle PGC‐1α Expression Is Associated with Exercise Performance and Increased Skeletal Muscle Weight

Scope

l ‐citrulline has recently been reported as a more effective supplement for promoting intracellular nitric oxide (NO) production compared to l ‐arginine. Here, the effect of l ‐citrulline on skeletal muscle and its influence on exercise performance were investigated. The underlying mechanism of its effect, specifically on the expression of skeletal muscle peroxisome proliferator‐activated receptor‐gamma coactivator‐1α (PGC‐1α), was also elucidated.

Methods and results

Six‐week‐old ICR mice were orally supplemented with l ‐citrulline (250 mg kg^?1) daily, and their performance in weight‐loaded swimming exercise every other day for 15 days, was evaluated. In addition, mice muscles were weighed and evaluated for the expression of PGC‐1α and PGC‐1α‐regulated genes. Mice orally supplemented with l ‐citrulline had significantly higher gastrocnemius and biceps femoris muscle mass. Although not statistically significant, l ‐citrulline prolonged the swimming time to exhaustion. PGC‐1α upregulation was associated with vascular endothelial growth factor α (VEGFα) and insulin‐like growth factor 1 (IGF‐1) upregulation. VEGFα and IGF‐1 are important for angiogenesis and muscle growth, respectively, and are regulated by PGC‐1α. Treatment with NG‐nitro‐l ‐arginine methyl ester hydrochloride (l ‐NAME), a nitric oxide synthesis inhibitor, suppressed the l ‐citrulline‐induced PGC‐1α upregulation in vitro.

Conclusion

Supplementation with l ‐citrulline upregulates skeletal muscle PGC‐1α levels resulting in higher skeletal muscle weight that improves time to exhaustion during exercise.

     

Linear eigenvalue code for edge plasma in full tokamak X-point geometry

A new code is presented for solving linear eigenvalue problems from fluid models of the edge plasma of tokamaks. The 2DX code solves linearized fluid equations in a 2D cross-section of the plasma, with toroidal mode number resolving the third dimension. Geometry capabilities include both closed and open field lines, allowing solution of X-point problems as well as a variety of other toroidal and cylindrical systems. The code generates a pair of sparse matrices forming a generalized eigenvalue problem which is then solved using a standard sparse eigensolver package. Use of a specialized equation parser permits a high degree of flexibility in both equations and coordinate systems. Both analytic and full geometry benchmark cases are presented.     

A symposium on psychologists in schools of medicine in 1977.

Introduces a series of 4 articles reporting the results of a survey of organizational structure, career status, and satisfaction of psychologists in medical schools, the range and pattern of graduate programs offered, and a general overview. (5 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Evaluating competency in the diagnostic interview among graduate psychology students: Development of generic scales.

Both graduate students and their trainers are concerned with reliable and valid evaluations of trainee skills. This article reports development of a unique system to evaluate objectively the diagnostic interview competency among professional psychology graduate students. Two training outcomes, skills used in the diagnostic interview and global interview quality, and one training process, student group supervision behaviors in diagnostic seminars, were measured. Development of generic scales is described, initial results reported, and system benefits and weaknesses are noted. Recommendations for evaluating students' competency at conducting diagnostic interviews are offered to trainers and educators, and potential clinical applications are highlighted for practitioners. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Stream-based semi-supervised learning for recommender systems

To alleviate the problem of data sparsity inherent to recommender systems, we propose a semi-supervised framework for stream-based recommendations. Our framework uses abundant unlabelled information to improve the quality of recommendations. We extend a state-of-the-art matrix factorization algorithm by the ability to add new dimensions to the matrix at runtime and implement two approaches to semi-supervised learning: co-training and self-learning. We introduce a new evaluation protocol including statistical testing and parameter optimization. We then evaluate our framework on five real-world datasets in a stream setting. On all of the datasets our method achieves statistically significant improvements in the quality of recommendations.