National Science Education Standards

This ebook is the first authorized digital version of Kernighan and Ritchie's 1988 classic, The C Programming Language (2nd Ed.). One of the best-selling programming books published in the last fifty years, "K&R" has been called everything from the "bible" to "a landmark in computer science" and it has influenced generations of programmers. Available now for all leading ebook platforms, this concise and beautifully written text is a "must-have" reference for every serious programmers digital library.

As modestly described by the authors in the Preface to the First Edition, this "is not an introductory programming manual; it assumes some familiarity with basic programming concepts like variables, assignment statements, loops, and functions. Nonetheless, a novice programmer should be able to read along and pick up the language, although access to a more knowledgeable colleague will help."

The C programming language

In many earth sciences applications, the geological objects or structures to be reproduced are curvilinear, e.g., sand channels in a clastic reservoir. Their modeling requires multiple-point statistics involving jointly three or more points at a time, much beyond the traditional two-point variogram statistics. Actual data from the field being modeled, particularly if it is subsurface, are rarely enough to allow inference of such multiple-point statistics. The approach proposed in this paper consists of borrowing the required multiple-point statistics from training images depicting the expected patterns of geological heterogeneities. Several training images can be used, reflecting different scales of variability and styles of heterogeneities. The multiple-point statistics inferred from these training image(s) are exported to the geostatistical numerical model where they are anchored to the actual data, both hard and soft, in a sequential simulation mode. The algorithm and code developed are tested for the simulation of a fluvial hydrocarbon reservoir with meandering channels. The methodology proposed appears to be simple (multiple-point statistics are scanned directly from training images), general (any type of random geometry can be considered), and fast enough to handle large 3D simulation grids.

Conditional Simulation of Complex Geological Structures Using Multiple-Point Statistics

In this study I investigated how collaborative interactions influence problem-solving outcomes. Conversations of twelve 6th-grade triads were analyzed utilizing quantitative and qualitative methods. Neither prior achievement of group members nor the generation of correct ideas for solution could account for between-triad differences in problem-solving outcomes. Instead, both characteristics of proposals and partner responsiveness were important correlates of the uptake and documentation of correct ideas by the group. Less successful groups ignored or rejected correct proposals, whereas more successful groups discussed or accepted them. Conversations in less successful groups were relatively incoherent as measured by the extent that proposals for solutions in these groups were connected with preceding discussions. Performance differences observed in triads extended to subsequent problem-solving sessions during which all students solved the same kinds of problems independently. These findings suggest that t...

When Smart Groups Fail

This paper studies the problem of efficiently schedulling fully strict (i.e., well-structured) multithreaded computations on parallel computers. A popular and practical method of scheduling this kind of dynamic MIMD-style computation is “work stealing,” in which processors needing work steal computational threads from other processors. In this paper, we give the first provably good work-stealing scheduler for multithreaded computations with dependencies.Specifically, our analysis shows that the expected time to execute a fully strict computation on P processors using our work-stealing scheduler is T1/P + O(T ∞ , where T1 is the minimum serial execution time of the multithreaded computation and (T ∞ is the minimum execution time with an infinite number of processors. Moreover, the space required by the execution is at most S1P, where S1 is the minimum serial space requirement. We also show that the expected total communication of the algorithm is at most O(PT ∞( 1 + nd)Smax), where Smax is the size of the largest activation record of any thread and nd is the maximum number of times that any thread synchronizes with its parent. This communication bound justifies the folk wisdom that work-stealing schedulers are more communication efficient than their work-sharing counterparts. All three of these bounds are existentially optimal to within a constant factor.

/pdf/scheduling-multithreaded-computations-by-work-stealing-3a6mnq5122.pdf

Scheduling multithreaded computations by work stealing

In implementing parallel programs, it is important to find strategies for controlling parallelism that make the most effective use of available resources. In this paper, we introduce a dynamic strategy called WorkCrews for controlling the use of parallelism on small-scale, tightly-coupled multiprocessors. In the WorkCrew model, tasks are assigned to a finite set ofworkers. As in other mechanisms for specifying parallelism, each worker can enqueue subtasks for concurrent evaluation by other workers as they become idle. The WorkCrew paradigm has two advantages. First, much of the work associated with task division can be deferred until a new worker actually undertakes the subtask and avoided altogether if the original worker ends up executing the subtask serially. Second, the ordering of queue requests under WorkCrews favors coarse-grained subtasks, which reduces further the overhead of task decomposition.

Workcrews: an abstraction for controlling parallelism

At a cost to both their own opportunities and society's ability to produce people with much-needed technical skills, women continue to be underrepresented in computer science degree programs at both the undergraduate and graduate level. Although some of the barriers that women face have their foundations in cultural expectations established well before the college level, we believe that departments can take effective steps to increase recruitment and retention of women students. This paper describes several strategies we have adopted at Stanford over the past decade.

/pdf/encouraging-women-in-computer-science-ajcmlxfsrm.pdf

Encouraging women in computer science

The authors describe the Pluribus multiprocessor system, outline several techniques used to achieve fault-tolerance, describe their field experience to date, and mention some potential applications. The Pluribus system places the major responsibility for recovery from failures on the software. Failing hardware modules are removed from the system, spare modules are substituted where available, and appropriate initialization is performed. In applications where the goal is maximum availability rather than totally fault-free operation, this approach represents a considerable savings in complexity and cost over traditional implementations. The software-based reliability approach has been extended to provide enror-handling and recovery mechanisms for the system software structures as well. A number of Pluribus systems have been built and are currently in operation. Experience with these systems has given us confidence in their performance and maintainability, and leads us to suggest other applications that might benefit from this approach.

Pluribus&#8212;An operational fault-tolerant multiprocessor

The introductory computer science at Stanford University have a combined annual enrollment of over 1000 students. Teaching introductory programming to a population of this size requires significant instructional support to ensure that students receive the individual attention most beginning programmers need. This paper describes the approach that has evolved at Stanford for the introductory computer science courses, which is based on the extensive use of advanced undergraduates to teach sections of the introductory course. In our experience, using undergraduates as part of the teaching staff has created an effective learning environment for both the students in the classes and the undergraduate section leaders themselves.

/pdf/using-undergraduates-as-teaching-assistants-in-introductory-4yot8qa5xq.pdf

Using undergraduates as teaching assistants in introductory programming courses: an update on the Stanford experience

This paper describes the implementation of MiniJava, a teaching-oriented programming language closely based on the Java language developed by Sun Microsystems [6]. The core of the MiniJava environment is a restricted subset of the standard Java release and is designed to reduce the intimidation factor introductory students experience when they encounter a system as large as the Java environment. The paper outlines the particular restrictions and extensions that define MiniJava along with pedagogical justifications for each.

https://cs.stanford.edu/people/eroberts/papers/SIGCSE-2001/MiniJava.pdf

Eric Roberts

Papers

Workcrews: an abstraction for controlling parallelism

Encouraging women in computer science

Pluribus—An operational fault-tolerant multiprocessor

Using undergraduates as teaching assistants in introductory programming courses: an update on the Stanford experience

An overview of MiniJava

Eric Roberts

Papers

Workcrews: an abstraction for controlling parallelism

Encouraging women in computer science

Pluribus&#8212;An operational fault-tolerant multiprocessor

Using undergraduates as teaching assistants in introductory programming courses: an update on the Stanford experience

An overview of MiniJava

Pluribus—An operational fault-tolerant multiprocessor