35983610
Sorting of textual data bases: A variety generation approach to distribution sorting
Abstract A method of sorting large textual data-bases by computer using external storage is proposed. The range of sort-keys in a sample of data to be sorted is divided into a fixed set of partitions, which should also give an adequate representation of new data from a similar source. The partitions are composed of ordered key ranges. An incoming data stream is distributed into a series of bins according to the partition in which the key lies, and the bins are then seperately sorted, using an internal sort, to give an ordered file. It is shown how the number of disc accesses needed depends on the manner in which the bins become filled, and thus on statistics of the data. Experiments using an INSPEC data-base give information on which estimates of the efficiency of the method can be based.
46025440
The use of binary search trees in external distribution sorting
Abstract A new method of external distribution sorting called tree partitioning is suggested. It involves the use of a binary tree to split an incoming file into successively smaller partitions until these are small enough to be sorted internally. The tree is generated from a sample of data of the same type as those to be sorted using that tree. The method is therefore suitable in cases where some regularity in the data is to be expected, as is the case, for example, with words from a textual or bibliographic database. The number of disc accesses during a tree partitioning sort were calculated in a simulation using files of up to 900,000 text words extracted from British National Bibliography catalogue files. These were compared with the actual numbers of disc accesses used by a standard sort-merge utility. Although the differences were in general not large, the comparison was favourable to tree partitioning in the majority of cases.
24201818
Compression of Wiswesser Line Notations Using Variety Generation
36913632
E-Publishing Portal: A New Approach to Faculty Outreach
The recent journal price increases and state-wide budget cuts have forced librarians at the University of Maryland (UMD) to make outright cancellations to journals. The implementation of an in-house system for preserving scholarly work of faculty was necessary not only because of budgetary stringency. The ongoing “scholarly communication crisis”, the recognition that the library system needs to be changed, the need for archiving e-journal content has prompted the construction of an institutional repository. This poster aims to identify issues encountered during the design process of a digital repository and suggests possible solutions. New roles of the users of this newly implemented system are described. The main elements of the service are outlined, outreach methodologies are discussed, and faculty concerns are addressed.
12212241
Java Implementation Verification Using Reverse Engineering
An approach to system verification is described in which design artefacts produced during forward engineering are automatically compared to corresponding artefacts produced during reverse engineering. The goal is to automatically determine if an implementation is consistent with the original design. In the system described, XML Metadata Interchange (XMI) representations of Unified Modelling Language (UML) class diagrams are recovered from compiled Java class files. These are automatically compared with the corresponding diagrams produced during forward engineering by software engineers using CASE tools. Examples are provided in which reversed engineered UML class diagrams differ from those produced during forward engineering but are still faithful to the original design intent. Such differences are often due to more abstract system representations being captured in forward engineered design artefacts, the inclusion of design attributes and annotations that are not retained in the final implementation, and issues associated with the use of weakly typed containers. In other cases, differences indicate a deviation from the intended design. It is this latter type of difference that this paper is particularly interested in identifying. We advocate that an automated comparison of forward and reverse engineering artefacts should be performed during formal code inspection preparation and used to guide human review of the identified differences.
6134873
Recognizing and Responding to Student Affect
This paper describes the use of wireless sensors to recognize student emotion and the use of pedagogical agents to respond to students with these emotions. Minimally invasive sensor technology has reached such a maturity level that students engaged in classroom work can us sensors while using a computer-based tutor. The sensors, located on each of 25 student's chair, mouse, monitor, and wrist, provide data about posture, movement, grip tension, facially expressed mental states and arousal. This data has demonstrated that intelligent tutoring systems can provide adaptive feedback based on an individual student's affective state. We also describe the evaluation of emotional embodied animated pedagogical agents and their impact on student motivation and achievement. Empirical studies show that students using the agents increased their math value, self-concept and mastery orientation.
2090341
Z in practice
Using Z. Structure, Process, Fluency. The Established Strategy. Security Properties. Other Approaches to Z Specification. Validation. Putting Together Your Method. House Style. A Word Counting Utility. Roles in Space. Structuring a Video Shop. Promoting Snakes and Ladders. Refining the Tower of Hanoi. Be Abstract. Sets or Functions?. Sets, Quantifiers, or Toolkit?. Sequences are Functions are Relations are Sets. Error Handling Styles. Promotion. Using Free Types. Using Bags. A Function Calculator. Making Schemas Work for you. Exploiting the Power of the Language. A Real Number Toolkit. and Finally...
36780179
President's information technology advisory committee (PITAC): subcommittee on transforming the government
A method for controlling a force-commutated inverter coupled between an electrochemical cell and a power grid for adjusting the magnitude and direction of the electrical energy flowing therebetween. Both the real power component and the reactive power component of AC electrical energy flow can be independently varied through the switching waveform presented to the intermediately coupled inverter. A var error signal is derived from a comparison of a var command signal with a signal proportional to the actual reactive power circulating between the inverter and the power grid. This signal is presented to a voltage controller which essentially varies only the effective magnitude of the fundamental voltage waveform out of the inverter, thereby leaving the real power component substantially unaffected. In a similar manner, a power error signal is derived by a comparison of a power command signal with a signal proportional to the actual real power flowing between the electrochemical cell and the power grid. This signal is presented to a phase controller which varies only the phase of the fundamental component of the voltage waveform out of the inverter relative to that of the power grid and changes only the real power in proportion thereto, thus leaving the reactive power component substantially unaffected.