Examination of the software architecture change characterization scheme using three empirical studies

Software maintenance is one of the most crucial aspects of software development. Software engineering researchers must develop practical solutions to handle the challenges presented in maintaining mature software systems. Research that addresses practical means of mitigating the risks involved when changing software, reducing the complexity of mature software systems, and eliminating the introduction of preventable bugs is paramount to today’s software engineering discipline. The Software Architecture Change Characterization Scheme (SACCS) provides software maintainers with a systematic approach to analyzing and characterizing the impact of a change prior to its implementation. SACCS was designed to help novice developers understand change requests, facilitate discussion among developers, and provide a higher-quality change compared with an ad hoc approach. In addition, this paper describes three controlled experiments designed to assess the viability of using SACCS and its ability to fulfill its goals. The successive studies build upon each other to enable progressive insights into the viability of the scheme. The results indicate that SACCS: 1) provides insight into the difficulty of a change request by assisting novice developers to consider various aspects of the request’s potential to impact the system, 2) helps to facilitate discussion among developers by providing a common tool for change assessment, and 3) is a useful tool for supporting change implementation. The three experiments provide insight into the usefulness of SACCS, motivate additional research questions, and serve as a baseline for moving forward with research and further development of the approach.     

Brain–behavior correlations: Relationships between mother–stranger face processing and infants' behavioral responses to a separation from mother.

Event-related potentials (ERPs) were recorded from 6-month-olds (N = 30) as they looked at pictures of their mother's face and a stranger's face. Negative component (Nc) and P400 component responses from the ERP portion of the study were correlated with behavioral responses of the infants during a separation from their mothers. We measured the mother-directed infant behaviors of distress and visual search for mother during separation in order to determine if they were predictive of infants' brain responses to pictures of the mother's face versus a stranger's face. These behavioral measures are important because they likely reflect the functioning of the emerging mother–child relationship and inform debates about interactions between social experience and face processing. Infant distress and visual search for mother during separation were predictive of face processing ERPs, and this relationship differed across mother and stranger face presentations. In particular, distress was associated with larger amplitude P400 and Nc responses to the mother's face, and visual search for mother was associated with longer P400 and Nc latencies to the stranger's face. Implications for the developing mother–child relationship and face processing system are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cognitive-behavioral stress management intervention decreases the prevalence of depression and enhances benefit finding among women under treatment for early-stage breast cancer.

The authors tested effects of a 10-week group cognitive-behavioral stress management intervention among 100 women newly treated for Stage 0-II breast cancer. The intervention reduced prevalence of moderate depression (which remained relatively stable in the control condition) but did not affect other measures of emotional distress. The intervention also increased participants' reports that having breast cancer had made positive contributions to their lives, and it increased generalized optimism. Both remained significantly elevated at a 3-month follow-up of the intervention. Further analysis revealed that the intervention had its greatest impact on these 2 variables among women who were lowest in optimism, at baseline. Discussion centers on the importance of examining positive responses to traumatic events—growth, appreciation of life, shift in priorities, and positive affect—as well as negative responses. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A class library for implementing, testing, and debugging concurrent programs

We describe the Modern Multithreading (MM) class library. MM is a class library consisting of thread and synchronization classes that provide significant support for testing and debugging multithreaded programs. The synchronization classes implement commonly used synchronization objects such as semaphores, monitors, and asynchronous and synchronous message passing channels, for programs that run on a single computer or on a distributed system. MM uses controlled executions to provide program tracing and replay and to support a number of implementation-based and specification-based testing techniques, including non-deterministic and deterministic testing and several forms of reachability testing. MM is portable and easy to use, and has been implemented in Java and C++, with C++ versions for the POSIX Pthreads library and for the Windows Win32 API.     

Assessment of relationship-specific incentive and threat sensitivities: Predicting satisfaction and affect in adult intimate relationships.

Self-report scales assessing relationship-specific incentive and threat sensitivity were created. Initial tests of factor structure and associations with relationship quality were conducted in a sample of persons in intimate relationships (Study 1). Associations with conceptually related measures were examined to determine convergent and discriminant validity in a sample of dating couples (Study 2). Cross-validation of the factor structure was established in engaged couples (Study 3) and in newlywed couples (Study 4). In Study 4, couples also engaged in a laboratory-based threat task (discussion about a significant marital problem) and incentive task (discussion about loving aspects of the partner/marriage). Relationship incentive sensitivity predicted higher positive affect after the incentive task for both husbands and wives. Relationship threat sensitivity predicted greater anxiety in response to the threat laboratory task for wives only. Implications of approach and avoidance motivations in close relationship processes and outcomes are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Negative affect and barriers to exercise among early stage breast cancer patients.

Objective: To assess the relative frequency of and barriers to exercise among women with breast cancer while controlling for cancer-relevant and demographic factors. Design: The present study employed concurrent samples, correlational research design. Main Outcome Measures: Exercise frequency and its association with negative affect and barriers to exercise, independent of cancer treatment, among women (N = 176) with Stage I or II breast cancer who were 3, 6, and 12 months postsurgery. Results: After accounting for cancer-relevant and control variables, degree of negative affect and frequency of perceived barriers were significantly inversely associated with exercise. Conclusion: These findings suggest that attention to both emotional factors and psychosocial barriers to exercise may be warranted to further understand exercise among women with early stage breast cancer. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The dawning of a past: The emergence of long-term explicit memory in infancy.

The ability to recall information about the past is thought to emerge in the 2nd half of the 1st year of life. Although there is evidence from both cognitive neuroscience and behavioral psychology to support this hypothesis, there is little longitudinal evidence with which the question can be addressed. Infants' memory abilities were tested between the ages of 9 and 16 months using elicited and deferred imitation. Infants' memory for events was tested after delays ranging from 1 to 6 months. The results suggest that at 9 months of age, infants are able to store and retrieve representations over delays of as many as 4 weeks but not over long delays. In contrast, 10-month-olds have at their disposal a system that allows encoding and retrieval of event representations over delays of up to 6 months. These results support the idea that the system that underlies long-term ordered recall emerges near the end of the 1st year of life. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hyperbranched polycarbosiloxanes and polycarbosilanes via bimolecular non-linear hydrosilylation polymerization

The syntheses and selected structure–property relationships of two series of polycarbosiloxanes (HB-PCSOX) and polycarbosilanes (HB-PCS) prepared by the platinum-catalyzed bimolecular non-linear hydrosilylation polymerizations of commercially available 1,3-diallyl- or 1,3-divinyl- disiloxanes or disilanes and tri- or tetra-functional siloxysilanes or silanes (i.e., A_x + B_y polymerization systems where x = 2 and y = 3 or 4) are described. The polymerizations were controlled to avoid gelation and ensure preparation of non-crosslinked soluble polymer products by adjusting the molar ratios of the reacting A (allylsilyl, Si–CH₂–CHCH₂, or vinylsilyl, Si–CHCH₂) and B (silyl, Si–H) reactive functional groups such that r ≤ 1/[(x ? 1)(y ? 1)] or r ≥ (x ? 1)(y ? 1) where r = [A]/[B]. The polymers were characterized by IR, ¹H, ¹³C and ²⁹Si NMR, SEC, DSC and TGA. Their molecular weights were found to increase in the following order of the side-group substitution in the 1,3-divinyldisiloxane monomer used: EtO > Me > MePh > Ph₂, consistent with the increased electron-donation to the vinyl groups causing their increased reactivity in hydrosilylation. These polymers represent unique yet easily and economically available multifunctional nanoscopic dendritic building blocks for more complex 3D nano-structured materials for a variety of applications in electronics, photonics, lithography, specialty coatings, etc.     

Distributed reachability testing of concurrent programs

Reachability testing is an approach to verifying concurrent programs. During reachability testing, every partially ordered synchronization sequence of a program with a given input is exercised exactly once. In this paper, we present the design and implementation of a distributed reachability testing algorithm for a cluster of workstations. This algorithm allows different test sequences to be exercised concurrently by different workstations without any synchronization, and without any duplication of sequences among workstations. Dynamic load balancing is performed using a work‐stealing scheme. A novel aspect of this scheme is that work‐stealing requests progress in rounds. This round‐based structure identifies overloaded workstations to target for work stealing. Empirical studies show good speedup for four benchmark Java programs and one Lotos specification. Copyright © 2010 John Wiley & Sons, Ltd.     

Large-scale,hypervelocity, high-fidelity interceptor lethality development in AEDC's range G

The hypervelocity ballistic range G at the Arnold Engineering Development Center (AEDC) is extensively used to conduct kinetic energy lethality tests for the Missile Defense Agency (MDA). Over the years, AEDC has continuously responded to the lethality test and evaluation requirements of Ballistic Missile Defense Systems (BMDS) at hypervelocity intercept conditions. Projectiles launched from two-stage light-gas guns experience acceleration loads that are typically orders of magnitude greater than those of the actual missile defense system. These acceleration loads drive design compromises in the projectiles' geometry and mass–density distribution necessary to survive the launch environment. A “high-fidelity” projectile with the proper geometry and mass–density distribution would provide a more representative simulation of the flight vehicle kinetic energy release at impact. Prior to the current upgrades, the range G facility provided the capability to launch large projectiles [8-in. (203-mm) diameter] with weights up to 12 kg at launch velocities up to 4 km/s but at acceleration loads near 40 K g's. Current upgrades provide for the capability to launch large-scale “higher fidelity” projectiles at the same high velocities but at half the g loads. In addition, AEDC is developing a new technique for controlling the projectile pitch at the point of impact with a simulated target. These unique capabilities will make it possible to obtain more flight-representative lethality data in a ballistic range. This paper describes the upgraded capabilities now in place and continuing plans for further upgrades.