Automated unit-level testing with heuristic rules

Software testing plays a significant role in the development of complex software systems. Current testing methods generally require significant effort to generate meaningful test cases. The QUEST/Ada system is a prototype system designed using CLIPS to experiment with expert system based test case generation. The prototype is designed to test for condition coverage, and attempts to generate test cases to cover all feasible branches contained in an Ada program. This paper reports on heuristics sued by the system. These heuristics vary according to the amount of knowledge obtained by preprocessing and execution of the boolean conditions in the program

Fault-tolerant quantum computer architectures using hierarchies of quantum error-correcting codes

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2008.Includes bibliographical references (p. 221-238).Quantum computers have been shown to efficiently solve a class of problems for which no efficient solution is otherwise known. Physical systems can implement quantum computation, but devising realistic schemes is an extremely challenging problem largely due to the effect of noise. A quantum computer that is capable of correctly solving problems more rapidly than modern digital computers requires some use of so-called fault-tolerant components. Code-based fault-tolerance using quantum error-correcting codes is one of the most promising and versatile of the known routes for fault-tolerant quantum computation. This dissertation presents three main, new results about code-based fault-tolerant quantum computer architectures. The first result is a large new family of quantum codes that go beyond stabilizer codes, the most well-studied family of quantum codes. Our new family of codeword stabilized codes contains all known codes with optimal parameters. Furthermore, we show how to systematically find, construct, and understand such codes as a pair of codes: an additive quantum code and a classical (nonlinear) code. Second, we resolve an open question about universality of so-called transversal gates acting on stabilizer codes. Such gates are universal for classical fault-tolerant computation, but they were conjectured to be insufficient for universal fault-tolerant quantum computation. We show that transversal gates have a restricted form and prove that some important families of them cannot be quantum universal. This is strong evidence that so-called quantum software is necessary to achieve universality, and, therefore, fault-tolerant quantum computer architecture is fundamentally different from classical computer architecture. Finally, we partition the fault-tolerant design problem into levels of a hierarchy of concatenated codes and present methods, compatible with rigorous threshold theorems, for numerically evaluating these codes.(cont.) The methods are applied to measure inner error-correcting code performance, as a first step toward elucidation of an effective fault-tolerant quantum computer architecture that uses no more than a physical, inner, and outer level of coding. Of the inner codes, the Golay code gives the highest pseudothreshold of 2 x 10-3. A comparison of logical error rate and overhead shows that the Bacon-Shor codes are competitive with Knill's C₄/C₆ scheme at a base error rate of 10⁻⁴.by Andrew W. Cross.Ph.D

Synthesis and evaluation of fault-tolerant quantum computer architectures

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2005.Includes bibliographical references (p. 241-247).Fault-tolerance is the cornerstone of practical, large-scale quantum computing, pushed into its prominent position with heroic theoretical efforts. The fault-tolerance threshold, which is the component failure probability below which arbitrarily reliable quantum computation becomes possible, is one standard quality measure of fault-tolerant designs based on recursive simulation. However, there is a gulf between theoretical achievements and the physical reality and complexity of envisioned quantum computing systems. This thesis takes a step toward bridging that gap. We develop a new experimental method for estimating fault-tolerance thresholds that applies to realistic models of quantum computer architectures, and demonstrate this technique numerically. We clarify a central problem for experimental approaches to fault-tolerance evaluation--namely, distinguishing between potentially optimistic pseudo-thresholds and actual thresholds that determine scalability. Next, we create a system architecture model for the trapped-ion quantum computer, discuss potential layouts, and numerically estimate the fault-tolerance threshold for this system when it is constrained to a local layout. Finally, we place the problem of evaluation and synthesis of fault-tolerant quantum computers into a broader framework by considering a software architecture for quantum computer design.by Andrew W. Cross.S.M

The development of a program analysis environment for Ada

A unit level, Ada software module testing system, called Query Utility Environment for Software Testing of Ada (QUEST/Ada), is described. The project calls for the design and development of a prototype system. QUEST/Ada design began with a definition of the overall system structure and a description of component dependencies. The project team was divided into three groups to resolve the preliminary designs of the parser/scanner: the test data generator, and the test coverage analyzer. The Phase 1 report is a working document from which the system documentation will evolve. It provides history, a guide to report sections, a literature review, the definition of the system structure and high level interfaces, descriptions of the prototype scope, the three major components, and the plan for the remainder of the project. The appendices include specifications, statistics, two papers derived from the current research, a preliminary users' manual, and the proposal and work plan for Phase 2

Case Report: A Truck Driver with Pelvic Pain

Extraskeletal myxoid chondrosarcoma (EMC) is a relatively rare soft tissue malignancy, originally described in the 1950s and characterized as a distinct entity from chondrosarcoma of the bone in the 1970s. These tumors most commonly originate in the proximal extremities, and their occurrence in the genitourinary tract is exceedingly rare, with few case reports citing origination in its component organs. We present a clinical case report of an EMC originating from the base of the penis with significant local involvement of the bony pelvis

Mode-Locking in Driven Disordered Systems as a Boundary-Value Problem

We study mode-locking in disordered media as a boundary-value problem. Focusing on the simplest class of mode-locking models which consists of a single driven overdamped degree-of-freedom, we develop an analytical method to obtain the shape of the Arnol'd tongues in the regime of low ac-driving amplitude or high ac-driving frequency. The method is exact for a scalloped pinning potential and easily adapted to other pinning potentials. It is complementary to the analysis based on the well-known Shapiro's argument that holds in the perturbative regime of large driving amplitudes or low driving frequency, where the effect of pinning is weak.Comment: 6 pages, 7 figures, RevTeX, Submitte

Multimodal affective interaction: a comment on musical origins

THE RIGORS OF ESTABLISHING INNATENESS and domain specificity pose challenges to adaptationist models of music evolution. In articulating a series of constraints, the authors of the target articles provide strategies for investigating the potential origins of music. We propose additional approaches for exploring theories based on exaptation. We discuss a view of music as a multimodal system of engaging with affect, enabled by capacities of symbolism and a theory of mind

Decision regret in men living with and beyond nonmetastatic prostate cancer in the United Kingdom: A population‐based patient‐reported outcome study

Objective: Clinical options for managing nonmetastatic prostate cancer (PCa) vary. Each option has side effects associated with it, leading to difficulty in decision‐making. This study aimed to assess the relationship between patient involvement in treatment decision‐making and subsequent decision regret (DR), and quantify the impact of health‐related quality of life (HRQL) outcomes on DR. Methods: Men living in the United Kingdom, 18 to 42 months after diagnosis of PCa, were identified from cancer registration data and sent a questionnaire. Measures included the Decision Regret Scale (DRS), Expanded Prostate cancer Index Composite short form (EPIC‐26), EQ‐5D‐5L, and an item on involvement in treatment decision‐making. Multivariable ordinal regression was utilized, with DR categorized as none, mild, or moderate/severe regret. Results: A total of 17 193 men with stage I‐III PCa completed the DRS: 36.6% reported no regret, 43.3% mild regret, and 20.0% moderate/severe regret. The odds of reporting DR were greater if men indicated their views were not taken into account odds ratio ([OR] = 6.42, 95% CI: 5.39‐7.64) or were involved “to some extent” in decision‐making (OR = 4.63, 95% CI: 4.27‐5.02), compared with men who were “definitely” involved. After adjustment, including for involvement, men reporting moderate/big problems with urinary, bowel, or sexual function were more likely to experience regret compared with men with no/small problems. Better HRQL scores were associated with lower levels of DR. Conclusions: This large‐scale study demonstrates the benefit of patient involvement in treatment decision‐making for nonmetastatic PCa. However, men experiencing side effects and poorer HRQL report greater DR. Promoting engagement in clinical decision‐making represents good practice and may reduce the risk of subsequent regret

Functional expression of purinergic P2 receptors and transient receptor potential channels by the human urothelium

In addition to its role as a physical barrier, the urothelium is considered to play an active role in mechanosensation. A key mechanism is the release of transient mediators that activate purinergic P2 receptors and transient receptor potential (TRP) channels to effect changes in intracellular Ca 2ϩ . Despite the implied importance of these receptors and channels in urothelial tissue homeostasis and dysfunctional bladder disease, little is known about their functional expression by the human urothelium. To evaluate the expression and function of P2X and P2Y receptors and TRP channels, the human ureter and bladder were used to separate urothelial and stromal tissues for RNA isolation and cell culture. RT-PCR using stringently designed primer sets was used to establish which P2 and TRP species were expressed at the transcript level, and selective agonists/antagonists were used to confirm functional expression by monitoring changes in intracellular Ca 2ϩ and in a scratch repair assay. The results confirmed the functional expression of P2Y4 receptors and excluded nonexpressed receptors/channels (P2X 1, P2X3, P2X6, P2Y6, P2Y11, TRPV5, and TRPM8), while a dearth of specific agonists confounded the functional validation of expressed P2X 2, P2X4, P2Y1, P2Y2, TRPV2, TRPV3, TRPV6 and TRPM7 receptors/channels. Although a conventional response was elicited in control stromal-derived cells, the urothelial cell response to well-characterized TRPV1 and TRPV4 agonists/ antagonists revealed unexpected anomalies. In addition, agonists that invoked an increase in intracellular Ca 2ϩ promoted urothelial scratch repair, presumably through the release of ATP. The study raises important questions about the ligand selectivity of receptor/ channel targets expressed by the urothelium. These pathways are important in urothelial tissue homeostasis, and this opens the possibility of selective drug targeting. calcium; purinergic; transient receptor potential channel; urothelium THERE HAS BEEN a growing appreciation that rather than a simple passive barrier, the urothelium plays a more active role in the urinary tract. After physical or other damage, the urothelium will self-repair by switching from a mitotically quiescent to a highly regenerative state More intriguingly, the urothelium has been reported to possess sensory neuronal-like properties and to respond to mechanical and chemical stimulation through the release of transient mediators (4). Various mediators have been implicated, including ATP, nitric oxide, acetylcholine, and substance P (1, 7, 11). These short-lived mediators are considered to actuate suburothelial afferent neurons involved in the regulation of sensory perception and pain, but the urothelium is itself widely reported to express an array of receptors and channels that may respond in an autocrine/paracrine fashion to released mediators. These include purinergic P2X and P2Y (8, 24, 27), transient receptor potential (TRPV1, TRPV2, TRPV4, and TRPM8), acetylcholine (nicotinic and muscarinic), tachykinin, nerve growth factor, endothelin, sphingosine-1-phosphate, and bradykinin (3, 9, 15, 17) receptors. The outcome of such signaling is incompletely understood as it may play a bidirectional feedback role in modulating the neuronal signal and/or effect changes in urothelial homeostasis, such as barrier repair. It has also been suggested that abnormal expression of receptors and/or mediator release by the urothelium may be involved in dysfunctional diseases of the bladder, including idiopathic detrusor instability and interstitial cystitis Despite the literature reporting expression of these channels and receptors by the urothelium, consensus is confounded by contradictions in experimental approaches, including the species, specificity of reagents, and the nature of the tissue preparation (for a review, see Ref. 30). There has been limited characterization of these receptor/mediator signaling pathways in the human urothelium, where functional TRPV1 (10) and an autocrine-activated P2Y receptor pathway (19, 26) have been reported. Ultimately, this conflict and the lack of consensus are hindrances to the development of selective drugs. To attribute expression and function to specific tissue compartments, the present study was designed to define the functional expression of purinergic and transient receptors in the isolated human urothelium and stromal cells in situ and in vitro. A preliminary investigation revealed a lack of specificity of commercially available antibodies. For this reason, our rationalized experimental approach was to identify candidate receptors based on mRNA expression followed by confirmatory functional experiments to measure changes in intracellular Ca 2ϩ using specific agonists/antagonists. Finally, to examine whether receptor activation plays a role in urothelial homeostasis, we examined the effect of receptor activation on human urothelial scratch wound repair in vitro