This paper discusses the importance of teaching innovating skills in a computer science (CS) curriculum. The world is changing from a knowledge-based economy which depends upon the traditional left-brain skills to an innovation-based economy which relies more on right brain skills. The traditional skills taught in a CS curriculum remain very important to the success of its graduates. However, these skills now need to be augmented with innovating skills. The observations from teaching such a course and the plans for the future of the course are presented.

Location updates (LU) are emergency 911 procedures mandated by the FCC for cellular networks today; helping locate mobiles within 100 meters of their vicinity. This requires paging all mobiles within a vicinity regularly thereby leading to an increased use of bandwidth. This paper analyzes the existing schemes of hash based paging in LU procedures using Bloom filters (BF) and introduces two new schemes to improve performance: optimization of Bloom filters (OBF) and cumulative Bloom filters (CBF). An identifier field in the paging message is coded by applying hashing functions to create a BF and this is used to page a number of mobiles concurrently. False LU are the mobiles that may not belong to a particular paging area but still respond with LU updates. We observe that these false probabilities are very small and can be traded-off with the bandwidth gain. The results obtained compare the analytical and simulation results and their observation leads us to the goal of this research: to obtain a multi-fold increase in bandwidth gain at the cost of keeping the false positives to a realistic minimum

Undergraduate computer science degree programs often provide an opportunity for students to experience real software projects as a part of their programs of study. These experiences frequently reside in a course in which students form software development teams, are assigned to a project offered by a corporate sponsor and devote one or two semesters to the task of making progress on the project. In an ideal model, faculty mentor student teams who, in turn, behave as sub-contractors or consultants to the sponsor. Students work for a grade, not directly for the sponsor as a true sub-contractor would. In the ideal model, students demonstrate what they have learned about software engineering process, as well as their ability to implement programmed solutions. Student teams provide progress reports, both oral and written, and directly experience many of the challenges and successes of true software engineering professionals. This paper reports on one such program after 10 years of operation. The technologies and software development processes of interest to sponsors are summarized and presented as an informal survey. Student response is discussed in terms of software systems they produced and how they went about producing them. The maturation of these students as software engineering professionals is also discussed

Hardware innovations such as motes, RFIDs, embedded microprocessors, and wireless sensors, have provided the foundation for a plethora of new applications for business, government, industry, and individuals. These applications include connected cities, smart homes and appliances, improved security and surveillance, smart vehicles, business integration, and e-commerce. Rarely does a user complain about a software system being too fast. Even though processor speeds have increased significantly, access times for external storage have lagged, causing performance bottlenecks. This paper presents a new hashing scheme, tridirectional computed chaining, which is especially relevant for applications in which space may be limited but fast access is important. The performance enhancements result primarily from using a pseudolink field with three-way branching rather than one allowing only a linear chain.

Many current perfect hashing algorithms suffer from the problem of pattern collisions. In this paper, a perfect hashing technique that uses array-based tries and a simple sparse matrix packing algorithm is introduced. This technique eliminates all pattern collisions, and, because of this, it can be used to form ordered minimal perfect hashing functions on extremely large word lists. This algorithm is superior to other known perfect hashing functions for large word lists in terms of function building efficiency, pattern collision avoidance, and retrieval function complexity. It has been successfully used to form an ordered minimal perfect hashing function for the entire 24481 element Unix word list without resorting to segmentation. The item lists addressed by the perfect hashing function formed can be ordered in any manner, including alphabetically, to easily allow other forms of access to the same list.>

Many information systems require expandable files. Linear hashing is a well-known technique for growing a file without requiring a complete reinsertion of the data. With the advantage of expandability comes greater retrieval costs as compared to static file methods. A recent modification of linear hashing, Linear Hashing with Separators (LHS), requires only a single access of auxiliary memory. However, this method too has limitations. It introduces secondary clustering which increases insertion costs and it has lower storage utilisation than might be desirable. After surveying linear hashing and LHS, this paper introduces an algorithm called High Storage Utilisation for Single-Probe Retrieval (HSUSPR is read SOO-SPRAH). HSUSPR linear hashing maintains the single probe retrieval of LHS but with lower insertion costs and greater auxiliary storage utilisation. To achieve these benefits HSUSPR does use more primary memory for storing index information. Extensive experimental results are given comparing HSUSPR with LHS. Experimental results also are provided which indicate that the performance of HSUSPR is independent of the distribution of the key data. HSUSPR is particularly useful for information systems with many insertions and/or those systems involving real-time updates.

This paper advances an amalgamated model of software usability derived from much of the vast research on the subject. The model organizes that research into seven basic usability principles, their underlying attributes, and associated relative weights. This model of software usability for human‐computer interaction has two primary goals: (a) to allow software designers to make quantitative decisions about which usability attributes should be included in a design, and (b) to provide a usability metric by which software designs can be consistently rated and compared. Because ultimately it is the users of a software system who decide how easy its user interface is to manipulate, 988 users were asked to evaluate the model's effectiveness. They were requested to rank the importance of each attribute in the model. Word processing was chosen as the specific interface type. To ensure some similarity in the respondents’ backgrounds, questionnaires were sent to users of a leading word processor. The 332 responses were analyzed to provide insights into what makes software usable and to provide a basis for adjusting the model. (Although many results of the study support our intuitions about what should be included in a user interface, for some reason, the developers of most software products do not seem to be heeding the obvious wisdom.) The paper also discusses the effect of user experience, presents extensions, and gives a summary of the findings that should be useful to those designing user interfaces and those selecting them.

The paper advances an amalgamated model of software usability in conjunction with a method for improving the usability of commercial software products. The model organises the substantial amount of prior research on software usability into seven basic principles, their underlying attributes, and associated relative weights. This model of software usability for human-computer interaction has two primary goals: first, to allow software designers to make quantitative decisions about which usability attributes should be included in a design; and second, to provide a usability metric by which software designs can be consistently rated and compared. The paper focuses on the second goal. Since it is ultimately the users of a software system who decide its usability, the method proposed suggests that the users be made an integral part of the software design and development process. It recommends that the users of current and future software products be asked, through questionnaires, how well a product meets the principles and underlying attributes of usability as defined by the model. Only if the ultimate users of a product are pleased is a product likely to succeed. The paper reviews the model and its evaluation. It then illustrates the method by describing its use in evaluting a particular wordprocessing product, WordPerfect. In that evaluation, 988 questionnaires were sent to users of the product.

This article considers the effectiveness of using a signature tree to further accelerate text searching beyond the efficiency gained by the use of signatures alone. It briefly reviews how signatures improve the performance of text searching and then it introduces signature trees. An experiment to test their effectiveness is described and an analysis of the experimental results is given. Except for narrow signatures and patterns of length two, the improvement in text searching performance is a greater percentage than the increase in storage required for the signature tree. © 1990 John Wiley & Sons, Inc.

The purpose of this study was to develop a basic model of software usability for human-computer interaction that accomplishes two primary goals: to allow software designers to make quantitative decisions about which usability attributes should be included in a design, and to provide a usability metric by which software designs can be consistently rated and compared. The model of software usability presented amalgamates the results from much of the research on usability and organizes it into seven basic usability principles, their underlying attributes, and associated relative weights.>

Abstract This article presents a procedure for constructing a near‐perfect hashing function. The procedure, which is a modification of Cichelli's algorithm, builds the near‐perfect hashing function sufficiently fast to allow larger word sets to be used than were previously possible. The improved procedure is the result of examining the original algorithm for the causes of its sluggish performance and then modifying them. In doing so an attempt was made to preserve the basic simplicity of th original algorithm. The improved performance comes at the expense of more storage. The six modifications used to improve performance are explained in detail and experimental results are given for word sets of varying sizes.

Linear hashing is a technique for constructing dynamic files for direct access. It has an advantage over other dynamic methods in that it lacks a directory. However, a weakness of the method is that at high packing factors, it requires more probes on the average to access a record than do many of the static methods. This paper presents a straightforward modification of linear hashing which, according to experimental results, significantly reduces the average number of retrieval probes in almost aft cases when compared with standard linear hashing. The parameter of overflow page size is an important one for adjusting performance. By choosing an appropriate overflow page size, the user may obtain results which are also better or comparable to those of other variants of linear hashing. In addition, the paper analyzes the effects of varying the primary page size, the overflow page size, and the packing factor on retrieval performance.

Few endeavors are successful without the proper preparation. For students to learn successfully, they must be prepared for the task; they must be motivated. In the past, much of this motivation has come from sources beyond the classroom. The instructor has had to do little to motivate the students as long as he did not discourage them. Those external motivational factors are not as prominent as they once were and this circumstance places more of the responsibility for motivating the students on the instructor. This paper, which suggests procedures for motivating students, is intended to emphasize the importance of motivation in learning and to foster an awareness of it. The paper also notes the need for greater recognition for those who provide the motivation, that is, the instructors.

Computed chaining and predictors are two recent techniques for resolving hashing collisions which use a pseudolink field instead of an actual address link to group records which map to the same home address. With additional computation on the pseudolink, the actual address can be determined. The advantage of the pseudolink is that it often takes much less storage than an actual address would take. The authors note problems with the predictor method which must be overcome if the method is to be used successfully. They also compare the predictor method to computed chaining. They conclude with a discussion of the utility of multiple predictor, i.e. having more than one chain of pseudolinks for records with the same home address.

Communicating algorithms and processes is an integral part of computer science education yet in many instances is difficult to carry out effectively using traditional techniques. Using the computer as an aid in visualizing and understanding an algorithm is one way to improve this communication process. With the computer technology available to us today, it would be unfortunate if we did not make effective use of it in computer science education. (We don't want to be like the shoemaker's children.)

With the d i v e r s i t y of high-level programming languages available, selecting the " r i g h t " one for a computer science curriculum or course can be a befuddling process.For a multitude of reasons, such as the manner in which students approach problems to the u t i l i z a t i o n of scarce computing resources, the ramifications of a decision on the choice of a programming language are s i g n i f i c a n t throughout a computer science curriculum.The purpose of this paper is to provide information relevant to the selection process.Particular attention is given to COBOL, FORTRAN, Pascal, PL-I, and Snobol; both q u a l i t a t i v e and quantitative factors are considered.The quantitative results were obtained from processing a binary tree insertion and r e t r i e v a l algorithm in each language.The machine resources used for this algorithm are given for both interpreter and compiler versions of translators for each language.

This correspondence describes a microcomputer system, called ¿BE (for microprocessor-based English), for processing natural languages. Its techniques and facilities, however, should be extendible to other languages. By using the microprocessor as special purpose hardware for several functions of a natural language processor (in particular, hashing and parsing), the system aids computational linguists by increasing the computational power available for natural language investigations. An overview of ¿BE is given followed by a more detailed discussion of the hasher and parser. The paper concludes with specific applications of the microprocessor system to computational linguistics. ¿BE is not based on a particular theory of language so that the system's user may define his own theory and investigate its consequences. ¿BE contains facilities and capabilities to assist such investigations.

Abstract This paper studies the use of text signatures in string searching. Text signatures are a coded representation of a unit of text formed by hashing substrings into bit positions which are, in turn, set to one. Then instead of searching an entire line of text exhaustively, the text signature may be examined first to determine if complete processing is warranted. A hashing function which minimizes the number of collisions in a signature is described. Experimental results for two signature lengths with both a text file and a program file are given. Analyses of the results and the utility and application of the method conclude the discussion.

Much attention has been given to the content of introductory computer science courses, but based upon a perusal of introductory textbooks, it appears that somewhat less attention has been given to the programming exercises to be used in these courses. Programming exercises can be modified to provide a better educational experience for the student. An example of how atypical programming exercises were incorporated into an introductory programming language course is described.

In the decade since Curriculum '68 [1], the suggested structure of courses related to data management has evolved, as evidenced by the report of the ACM committee on curriculum in 1977 [2] and also noted by Dale [3]. A course in Curriculum '68 entitled “Information Organization and Retrieval” [IOR] does not appear in the 1977 report, while a new course in File Processing [FP] is included. Influenced by Curriculum '68, N.C. State in 1970 instituted a senior-level course entitled “Information Retrieval” to correspond essentially to the IOR course. Over the years that course in information retrieval has changed gradually, as material related to document retrieval has been supplanted by material related to file organization. Although the title has remained constant, the content is now more similar to FP than IOR. This paper describes the current project-oriented course in information retrieval which stresses the importance of query languages in an information retrieval system. In addition, the paper highlights the use and impact of interactive computing, the choice of a project implementation language, and the relationship of the course to an individual's transition from student to professional. The paper concludes with a comparison of project grade and the associated computer development time.

This paper illustrates the use of Augmented Transition Networks (ATNs) as a design tool for constructing document retrieval systems for those personalized applications which are too small or specialized to attract a commercial vendor. ATNs, which are explained in the context of this application, are used not only to improve the human/computer interface with the retrieval system but also to conceptually organize its structure.