Testing Library Specifications by Verifying Conformance Tests

Abstract. Formal specifications of standard libraries are necessary when statically verifying software that uses those libraries. Library specifications must be both correct, accurately reflecting library behavior, and useful, describing library behavior in sufficient detail to allow static verification of client programs. Specification and verification researchers regularly face the question of whether the library specifications we use are correct and useful, and we have collectively provided no good answers. Over the past few years we have created and refined a software engineering process, which we call the Formal CTD Process (FCTD), to address this problem. Although FCTD is primarily targeted toward those who write Java libraries (or specifications for existing Java libraries) using the Java Modeling Language (JML), its techniques are broadly applicable. The key to FCTD is its novel usage of library conformance test suites. Rather than executing the conformance tests, FCTD uses them to measure the correctness and utility of specifications through static verification. FCTD is beginning to see significant use within the JML community and is the cornerstone process of the JML Spec-a-thons, meetings that bring JML researchers and practitioners together for intensive specification writing sessions. This article describes the Formal CTD Process, its use in small case studies, and its broad application to the standard Java class library.

Practically Applicable Formal Methods

Abstract. Formal methods are considered to be highly expensive. There-fore, they are currently applied almost only in high risk software develop-ment. In this paper, we show that formal techniques can be also efficiently used in standard large-scale applications. We focus on the generation of specifications which state the termination condition of for loops in Java code (expressed as so called Java Modeling Language decreases clauses). We demonstrate that with help of relatively simple techniques it is pos-sible to successfully generate the clauses for almost 80 % of the loops in a number of widely deployed applications. Moreover, it turns out that the remaining 20 % cases contain loops which should be carefully reviewed by software quality assurance personnel. The results show that our tech-nique might be helpful in spreading the usage of formal methods onto typical business software

Pediatric applications of wideband acoustic immittance measures

Wideband acoustic immittance (WAI) measures have potential capability to improve newborn hearing screening outcomes and middle ear diagnosis for infants and children. To fully capitalize on these immittance measures for pediatric hearing care, developmental and pathologic effects need to be fully understood. Published literature on wideband immittance (reflectance, absorbance, tympanometry, and acoustic reflexes) is reviewed in this article to determine pathologic effects in newborns, infants, and children relative to standard audiologic tests such as otoacoustic emissions (OAEs), standard tympanometry, air and bone conduction auditory brainstem response, and otoscopy. Infants and children with surgically confirmed otitis media with effusion have lower absorbance in the mid-frequency range (1 to 3 kHz) for the affected ear(s). Newborns that do not pass OAE screening at birth also have lower absorbance for frequencies from 1 to 3 kHz, suggesting that nonpass results are frequently associated with middle ear issues at birth. In Newborn Hearing Screening Programs, WAI may help to interpret hearing screening results. Conclusions are limited by the fact that the true status of the middle ear and cochlea are not known for newborns and infants in studies that use OAE or tympanometry as the reference standard. Likelihood ratios for reflectance against surgery gold standards range from diagnostically suggestive to informative. Although some of the results are promising, limited evidence and methodological considerations restrict the conclusions that can be drawn regarding the diagnostic accuracy of WAI technologies in infants and children. Additional investigations using stronger gold standard comparisons are needed to determine which tools can most accurately predict middle ear status in the pediatric population