Incomplete Programs Research Articles

Compositional pointer and escape analysis for Java programs

This paper presents a combined pointer and escape analysis algorithm for Java programs. The algorithm is based on the abstraction of points-to escape graphs, which characterize how local variables and fields in objects refer to other objects. Each points-to escape graph also contains escape information, which characterizes how objects allocated in one region of the program can escape to be accessed by another region. The algorithm is designed to analyze arbitrary regions of complete or incomplete programs, obtaining complete information for objects that do not escape the analyzed regions. We have developed an implementation that uses the escape information to eliminate synchronization for objects that are accessed by only one thread and to allocate objects on the stack instead of in the heap. Our experimental results are encouraging. We were able to analyze programs tens of thousands of lines long. For our benchmark programs, our algorithms enable the elimination of between 24% and 67% of the synchronization operations. They also enable the stack allocation of between 22% and 95% of the objects.

Constructing an integrated visual programming environment

This paper presents an object-oriented architecture, called the Model-View-Shape (MVS) architecture, for constructing an Integrated Visual Programming Environment (IVPE), whose constituent tools deal with (fine-grained) language semantics, as well as a mass of graphics-drawing activities. This architecture enforces a layered and loosely-coupled structure, so that the user-interface part of components may be more independent, maintainable, and reusable than those proposed in the original model-view-controller architecture. An MVS class hierarchy, systematically constructed using C++, can be reused and extended with new semantics to rapidly develop new tools for an existing IVPE, or even an IVPE supporting more than one language. The present editors developed can be used to construct programs by specifying the associated flow information in explicit (visual) or implicit (textual) ways, while the (incremental) flow analysers can help analyse incomplete program fragments to locate and inform the user of possible errors or anomalies during programming.  1998 John Wiley & Sons, Ltd.

Solution procedures for the dynamic facility layout problem

Existing optimal solution procedures for the dynamic facility layout problem require the repeated solution of quadratic assignment problems within the framework of a dynamic program. The computational requirements for this problem necessitate the development of efficient algorithms for special cases of the problem and strong bounds for the general case of the problem. The concept of incomplete dynamic programming is applied to the dynamic facility layout problem to find the optimal solution to the problem with fixed rearrangement costs at exceptionally reduced solution times. Heuristics are also developed to provide a solution methodology for larger problems. A lower bound is developed for the general problem that dominates all existing bounds, and it is shown how the bound can be used as an initial test for optimality before the dynamic program is solved. Finally, the incomplete dynamic programming methodology is extended to find an upper bound for the general problem that dominates all previous bounds.

Separate computation of alias information for reuse

Interprocedural data flow information is useful for many software testing and analysis techniques, including data flow testing, regression testing, program slicing and impact analysis. For programs with aliases, these testing and analysis techniques can yield invalid results, unless the data flow information accounts for aliasing effects. Recent research provides algorithms for performing interprocedural data flow analysis in the presence of aliases; however, these algorithms are expensive, and achieve precise results only on complete programs. This paper presents an algorithm for performing alias analysis on incomplete programs that lets individual software components such as library routines, subroutines or subsystems be independently analyzed. The paper also presents an algorithm for reusing the results of this separate analysis when the individual software components are linked with calling modules. Our algorithms let us analyze frequently used software components, such as library routines or classes, independently, and reuse the results of that analysis when analyzing calling programs, without incurring the expense of completely reanalyzing each calling program. Our algorithms also provide a way to analyze large systems incrementally.

Separate computation of alias information for reuse

Interprocedural dataflow information is useful for many software testing and analysis techniques, including dataflow testing, regression testing, program slicing and impact analysis. For programs with aliases, these testing and analysis techniques can yield invalid results, unless the dataflow information accounts for aliasing effects. Recent research provides algorithms for performing interprocedural dataflow analysis in the presence of aliases; however, these algorithms are expensive, and achieve precise results only on complete programs. This paper presents an algorithm for performing alias analysis on incomplete programs, that lets individual software components such as library routines, subroutines, or subsystems be independently analyzed. The paper also presents an algorithm for reusing the results of this separate analysis when linking the individual software components with calling modules. The primary advantage of our algorithms is that they let us analyze frequently used software components, such as library routines or classes, independently, and reuse the results of that analysis when analyzing calling programs, without incurring the expense of completely reanalyzing each calling program.

Postsecondary education and the sub-baccalaureate labor market: Corrections and extensions

This paper presents results based on corrections to the data — the National Longitudinal Study of the Class of 1972 (NLS72) — used in two earlier papers on the effects of education in sub-baccalaureate labor markets. The corrected results confirm most of the earlier results except that, for men, the effects of vocational Associate degrees are insignificant while the effects of vocational credits earned are significant — confirming that under some circumstances there are economic benefits to small amounts of community college without earning degrees. Other corrected results confirm that those levels of education with positive returns seem to act as signals of ability. Finally, some extensions using the Survey of Income and Program Participation (SIPP) data are presented, generally confirming the variation in returns within the sub-baccalaureate labor market and the value of completing credentials rather than incomplete programs.

An Incomplete Program of Cellular Tyrosine Phosphorylations Induced by Kinase-defective Epidermal Growth Factor Receptors

Although signaling by the epidermal growth factor (EGF) receptor is thought to be dependent on receptor tyrosine kinase activity, it is clear that mitogen-activated protein (MAP) kinase can be activated by receptors lacking kinase activity. Since analysis of the signaling pathways used by kinase-defective receptors could reveal otherwise masked capabilities, we examined in detail the tyrosine phosphorylations and enzymes of the MAP kinase pathway induced by kinase-defective EGF receptors. Following EGF stimulation of B82L cells expressing a kinase-defective EGF receptor mutant (K721M), we found that ERK2 and ERK1 MAP kinases, as well as MEK1 and MEK2 were all activated, and SHC became prominently tyrosine-phosphorylated. By contrast, kinase-defective receptors failed to induce detectable phosphorylations of GAP (GTPase-activating protein), p62, JAK1, or p91STAT1, all of which were robustly phosphorylated by wild-type receptors. These data demonstrate that kinase-defective receptors induce several protein tyrosine phosphorylations, but that these represent only a subset of those seen with wild-type receptors. This suggests that kinase-defective receptors activate a heterologous tyrosine kinase with a specificity different from the EGF receptor. We found that kinase-defective receptors induced ErbB2/c-Neu enzymatic activation and ErbB2/c-Neu binding to SHC at a level even greater than that induced by wild-type receptors. Thus, heterodimerization with and activation of endogenous ErbB2/c-Neu is a possible mechanism by which kinase-defective receptors stimulate the MAP kinase pathway.

Abstract analysis with aspect

Aspect is a static analysis technique for detecting bugs in code based on three forms of abstraction: declarative specification, data abstraction and partiality (ignoring some behavioural details). Together, they bring efficiency (the checker runs almost as fast as a type checker), modularity (a procedure can be analysed independently of the procedures it calls) and incrementality (allowing the checking of incomplete programs). Aspect can detect errors that are not detectable by other static means, especially errors of omission, which are pervasive but usually hard to detect.

School-based substance abuse prevention: a review of the state of the art in curriculum, 1980-1990.

Substance use prevention studies published between 1980 and 1990 are reviewed for content, methodology and behavioral outcomes. Studies were classified based on the inclusion of 12 content areas: Information, Decision Making, Pledges, Values Clarification, Goal Setting, Stress Management, Self-Esteem, Resistance Skills Training, Life Skills Training, Norm Setting, Assistance and Alternatives. Six groups of programs (Information/Values Clarification, Affective Education, Social Influence, Comprehensive, Alternatives and Incomplete programs) are identified. Reports are analyzed for two major threats to validity, selection bias and statistical power. Program groups generally have similar selection biases but have important differences in statistical power. Comprehensive and Social Influence programs are found to be most successful in preventing the onset of substance use.

The calculus of context relations

We present the theory of context relations. Context relations are a method for incremental semantic analysis in language-specific editors, which is able to handle incomplete program fragments. The algorithm is generated from the definition of a language's static semantics and is based on inference rules and order-sorted unification. The paper presents the underlying mathematical theory, optimal incremental analysis algorithms, handling of user-defined polymorphism and overloading, and implementation issues. It is intended as the concluding report on a by now mature concept, which has successfully been used to generate efficient incremental type inferencers for languages like ADA and Fortran 8x.

Preparation and Control of Rapid, Multisegmented Responses in Simple and Choice Environments

Research investigating the preparation and control of rapid, multisegmented responses typically has assumed complete programming of the response occurring prior to movement initiation and has made use of a simple reaction time (RT) paradigm. A notable exception is Rosenbaum's work which proposed the Hierarchical Editor (HED) model that is specifically directed toward the control of movements in the choice environment. The purposes of this study were to investigate the assumption of complete programming prior to movement initiation and to compare predictions of the HED model with other programming models. Three experiments are reported in which subjects were required to tap either one, two, or three plates as rapidly as possible in either a simple or choice RT situation. The results were very consistent in these experiments even with several modifications in apparatus and methodology. Of particular interest were effects of movement complexity on RT and movement time (MT) for the first and second segments of the movement (M1 and M2). Choice RT (CRT) results consistently showed no increases in RT as the number of movement segments increased but showed significant increases in M1. For simple RT situations, however, there were small but consistent increases in RT as well as increases in M1 with increases in the number of movement parts. For both CRT and SRT results, small but nonsignificant increases were noted for M2. These results provide evidence for incomplete programming prior to response initiation. Although the SRT data can be accommodated by Henry's theory, the HED model appears to offer the best overall fit for the results.

Occupational illness: case detection by poison control surveillance.

To evaluate the usefulness of poison control center detection in occupational illness surveillance. Case series of all occupationally related exposures referred for poison control center consultation over 6 months. Follow-up structured interviews were done of exposed persons and health care providers. Cases were traced under established occupational illness reporting programs. A regional poison control center. Consecutive sample of 461 symptomatic occupational exposure cases. After exclusions and losses to follow-up, interview of 301 patients and the treating physician, physician's assistant, or nurse practitioner for the 223 of the patients under direct medical care. One hundred and fifty-five persons (61%; CI, 55% to 67%) had systemic or respiratory illness; 109 (36%; CI, 31% to 41%) had eye or skin conditions. Work practices were associated with exposures more often than technical failure; 118 persons (39%; CI, 33% to 45%) reported lack of respirators or other appropriate personal protective equipment. For 223 persons who received direct medical care, only five treating health care providers (2%; CI, 0.2% to 4%) reported occupational specialization, although occupational care was a regular practice activity for 128 of the health care providers (57%; CI, 51% to 63%). Sixty-seven cases (22%; CI, 17% to 27%) were detected by the Doctor's First Report surveillance program; 97 cases (32%; CI, 27% to 37%) comprised the maximal detection estimated for Occupational Safety and Health Administration surveillance. Poison control center detection provides a useful surveillance measure for occupational illness. The proportion of case detection failures by established surveillance programs suggests that the incidence of occupational illness in the United States, which is calculated from these incomplete programs, may be three to five times greater than previously estimated.

A LISP implementation of the model for ‘communicating sequential processes’

AbstractTo explain his abstract model of Communicating Sequential Processes, Hoare includes an implementation of the concepts being expounded as a set of LISP functions. However, the final sections are only described sketchily. This paper completes the missing details, and briefly discusses experience with the system. The usefulness of the implementation is enhanced by the addition of features to ensure that incomplete program fragments can be executed, and that no restrictions are placed on the way operators may be combined.

The programming environment for statistical tabulation

The Programming Environment for Statistical Tabulation ( PEST) is a system which adopts an unusual approach to statistical computing. Most such systems present one or more complete programs which are controlled by parameters of varying degrees of complexity; PEST adopts a different method and provides an incomplete program to which extra instructions must be added to specify the analysis that is required. Designed originally as a replacement for a similar system written in Algol 60, it now uses instead the more powerful and flexible Algol 68. This much neglected language is ideal for the purpose, enabling an ordinary user to obtain results with a limited range of simple statements and at the same time allowing an experienced programmer free access to facilities that compare most favourably with those of comparable languages. The efficiency of modern Algol 68 compilers means that the overhead of compiling the user's instructions as often as required is small and incurs no disadvantage by comparison with conventional packages.

The PSG system: from formal language definitions to interactive programming environments

The PSG programming system generator developed at the Technical University of Darmstadt produces interactive, language-specific programming environments from formal language definitions. All language-dependent parts of the environment are generated from an entirely nonprocedural specification of the language's syntax, context conditions, and dynamic semantics. The generated environment consists of a language-based editor, supporting systematic program development by named program fragments, an interpreter, and a fragment library system. The major component of the environment is a full-screen editor, which allows both structure and text editing. In structure mode the editor guarantees prevention of both syntactic and semantic errors, whereas in textual mode it guarantees their immediate recognition. PSG editors employ a novel algorithm for incremental semantic analysis which is based on unification. The algorithm will immediately detect semantic errors even in incomplete program fragments. The dynamic semantics of the language are defined in denotational style using a functional language based on the lambda calculus. Program fragments are compiled to terms of the functional language which are executed by an interpreter. The PSG generator has been used to produce environments for Pascal, ALGOL 60, MODULA-2, and the formal language definition language itself.

Stepwise refinement revisited

In this paper, rigorous application of stepwise refinement is explored. The steps of definition, decomposition, and completion are described, where completion is a newly introduced step. This combination of steps extends the use of stepwise refinement to larger systems. The notions of range, active objects, and backlog interface are introduced. Verification of incomplete programs via interactive testing is described. The paradigm is demonstrated in an example. The relationship between the paradigm and the current programming languages is considered. It is argued that the WHILE-DO loop is a harmful construct from this point of view.

Program Development on Graphical Workstations

The aim of this paper is to emphasize the merits of program development on graphical workstations. A workstation with a graphical display and a pointing device is an interesting base for new programming environments. Sufficient machine resources are provided to support advanced software development tools, and a considerable improvement of the programmer-machine interaction is possible. Program editing on graphical workstations is discussed. Using windows, a program can simultaneously be presented at several abstraction levels and hereby good program survey and rapid program navigation is provided. We discuss how to cope with the large set of commands in syntax-directed editors, and how to create programs using the pointing device as the primary input medium. Testing incomplete program sketches by simulating unimplemented facilities via so-called state editing is explained. Simple graphical means seem to be useful when observing the program state. It is argued why continuous program observation combined with programmer controlled execution speed (including reverse execution) is valuable. Examples are drawn from the Ekko design - a proposed integrated program development system for graphical workstations - and from an implemented syntax-directed editor on a Perq workstation.

A methodology for verifying programs

The paper investigates methods for applying an online interactive verification system designed to prove properties of PASCAL programs. The methodology provides techniques for developing a debugged and verified version starting from an incomplete program .

COCOA: A FORTRAN program for concordance and word-count processing of natural language texts

Description. The COCOA program is a highly flexible device for processing natural language texts. The program can produce word and vocabulary counts, concordances with context formats and location references, and word-frequency profiles. Texts supplied by the user may be in any language, although non-Roman characters or alphabets must be transliterated by means of characters or combinations available on input devices and acceptable to the computer on which the program is to be run. Texts may be analyzed with a referencing that makes possible the separate processing of textual or library subdivisions (e.g., author, title, chapter, speaker, page, etc.). Concordances may be produced with various lengths and formats of line contexts for each vocabulary word, keywords, and keyword groups. Word counts may be arranged in alphabetical and reverse alphabetical order, frequency order, and counts restricted by declared frequency. To make the program adaptable to diverse research requirements, the individual user may declare his own: (a) alphabet, punctuation marks, word separators, and word connectors; (b) multiple character letters for transliteration of non-Roman alphabets; (c) special signs to distinguish homographs in program processing and printouts; (d) special characters for denoting word groups to be processed together; (e) references to particular subdivisions of a text or text library for sub text processing; (f) reference format for concordances; (g) declaration for listing word co-occurences within a desired text proximity; (h) inclusion or exclusion of a specified word or words; and (i) list of specified suffixes declared for special processing by the user. Input. Three files are required to operate the COCOA program: (1) the all-FORTRAN IV COCOA program, (2) a 13-card which includes alphabet and special declarations, word length, text-selection statements, and concordance or word-count requests; and (3) the language text. The version of COCOA adapted to the DECsystem-10 computer requires only two input streams. The control file and text file are collapsed, and may be input with a single card deck, and retained on user disk files or DEC-Tape. Experience on the DECsystem-10 indicates maximum efficiency is attained by punching the language text onto IBM tab cards, creating a disk file of the text, using a standard editing routine on a time-sharing terminal to correct typographical errors, and then storing each text on tape for recall when the particular test is required for processing. The COCOA program (521 blocks) may be stored on the file structure or user disk file. Operating efficiency is greatly increased when the COCOA program is stored in a compiled, machine-readable form for immediate execution. Prior to program execution, three input/output files and four work files must be assigned. When the user executes the COCOA program, the reads the control file-from which it receives character, text, and format instructions, then it reads and processes the text in accordance with the control requests. The data which is thus generated is read onto two output disk files. Output. The output file contains the system diagnostics, including a copy of the control file and any COCOA error messages generated during an unsuccessful or incomplete program execution. The other output file is a record of the word counts, word and vocabulary totals, frequency profile, and text concordance. These tables may be printed from the user disk files by a simple lineprinter command. Restrictions. COCOA handles alphabets of up to 256 letters of one per letter, 128 letters at two characters, and 85 letters at three characters. The length of texts is theoretically infinite, and depends only upon the available core space (28K) and the user's disk space quota. A 2,000-word text may be processed with a log-in quota of 1,000 blocks.

Influences on Selection of the Type of Dam

Of those factors influencing the selection of a type of dam, the most difficult to evaluate are the characteristics of soils and rocks which form the foundation. The dam designer is cautioned against a premature fixation on criteria which may be changed by future explorations or revelations through construction excavations. A design procedure geared to the advancement in quality of foundation data is recommended. Examples are given to illustrate the design revisions, and economic losses which result when criteria are based on inadequate or incomplete exploratory programs. The fact that explorations and associated tests cannot identify conclusively underground conditions in advance of construction should be acknowledged by the owner and accepted by the contractor under terms of the construction contract. The owner should accept responsibility for the accuracy of geologic and soils data which are included in contract documents. Attempts to shift this responsibility to the contractor by inclusion of a disclaimer clause works against the owner's interest. Examples of a disclaimer clause, and also a specification clause providing for an equitable adjustment under changed conditions are included.