Showing papers on "Overhead (computing) published in 1979"

Progressive Refinement of Raster Images

Abstract: The transmission of high resolution raster images over low-bandwidth communication lines requires a great amount of time. User interaction in such a transmission environment can be frustrating. The problem can be eased somewhat by transmitting a series of low resolution approximations which converge to the final image. Several methods of computing such a series of images are presented. Each is related to a particular type of pyramid data structure. They rely on the ability of the local display device to overpaint an existing image, and generally require some transmission and computation overhead. However, one of the methods requires no transmission overhead and only a small amount of local computation. A notation is introduced that permits concise descriptions of the image refinement processes.

Dynamic Binary Search

Abstract: We consider search trees under time-varying access probabilities. Let $S = \{ B_1 , \cdots ,B_n \} $ and let $p_i^t $ be the number of accesses to object $B_i $ up to time t, $W^t = \sum {p_i^t } $. We introduce D-trees with the following properties.1) A search for $X = B_i $ at time t takes time $O(\log W^t /p_i^t )$. This is nearly optimal.2) Update time after a search is at most proportional to search time, i.e. the overhead for administration is small.

Variably supported container

Abstract: A container for suspending various small articles such as toiletries, poisons, spices, and plants from an overhead support at a plurality of elevations is provided. A releasably locking member for one-handed height adjustment of the container is further provided, as well as automatic retracting means for returning the container to a convenient storage position.

Overhead conveyor track system

Abstract: An overhead trolley conveyor system has an overhead track comprising a pair of angle irons each having an inwardly extending flange and an upwardly extending flange, the angle irons being supported in spaced relationship to each other by a plurality of strap members which impart a cant to the inwardly extending flanges which are adapted to support a pair of tapered wheels associated with an axle of a trolley.

Automatic brake sequencing for overhead support arm assemblies

Abstract: A roller-switch and cam, located at an intermediary joint of a plural arm overhead assembly, delays the unlocking of a brake at a next adjacent joint until the joint at which the cam and switch are located has diverged a predetermined angle from alignment.

Inputtoutput processing method of virtual space segment

Abstract: PURPOSE:To improve the efficiency of an input-output control program by enabling an input-output processor to take the place of an input-output control program as to the work which becomes an overhead.

Information processing system

Abstract: PURPOSE:To increase the through-put at the multiprogramming remarkably, by reducing the overhead of software processing so that efficient resouce common management can be realized by harwarization.

Suspension system for writing implements

Abstract: Apparatus for retractably extending an overhead supported writing implement maintains a uniform light retraction force upon the writing implement regardless of the degree of extension of the writing implement.

Page detection mechanism

Abstract: PURPOSE:To reduce an overhead through a fault process with a page-fault ganerating circuit controlled, by counting the number in use of pages in the past and by substituting a new page for the smallest number page of an access circuit in a page fault time.

A model of the performance of a rollback algorithm

Abstract: The performance characteristics of a rollback algorithm are analyzed in a simulation experiment. An overview of the operation of the rollback algorithm is presented, followed by a discussion of the simulation model and its parameters. The model, as implemented, consists of data definition, data manipulation command processing, and rollback facilities. The model is parameterized in terms of number of application tasks and amount of data sharing and driven by randomized streams of data manipulation language commands. The simulation experiment applies the model to a CODASYL DBMS in an environment in which the rollback algorithm is initiated by a deadlock detection procedure. The overhead of the rollback algorithm in this environment is projected in terms of CPU utilization and file accesses. The results indicate that the factors having the strongest influence upon the performance of the rollback algorithm are update frequency and the degree of data sharing among programs. The performance projections indicate that the rollback algorithm introduces only a small amount of overhead even in worst case situations.

Performance of distance protection applied to underground cables alone or mixed with overhead lines

Abstract: The unequal impedance angles of the positive and zero sequence underground-cable impedances, which are in variance with overhead lines, requires a study to evaluate the appropriate relay residual compnesation factor, which is of paramount importance for earth faults. The problem, in many cases, is provoked when the protected zone consists of a mix of underground cables and overhead lines. This paper shows the importance of having an accurate residual vectorial compensation together with a proper selected comparator characteristic.

On the Storage and Handling of Binary Data Using FORTRAN with Applications to Integer Programming

Abstract: Most integer programming algorithms involve at least some binary data handling, e.g., set membership, intersection, and union. This paper presents some of the important concerns involved in implementation. When the algorithms are coded for the computer an effort is sometimes made to take advantage of the basic binary configuration of the digital computer to aid in the storage and handling of such data. In the past this has meant the use of assembly language subroutines. This paper demonstrates a procedure for achieving the same objectives in the main program using FORTRAN. The obvious advantage of the procedure is the elimination of the several storage and retrieval operations for register values as the program shifts control from the main routine to the subroutine and back again. Of particular interest are (1) the use of the computer arithmetic to achieve the relative complement operation and (2) the importance of additional savings due to overhead reduction when bit storage is used. Computational result...

Performance Collapse due to Overhead in a Simple, Single-Server Queuing System.

Abstract: : We consider a simple model of overhead in batch computer systems and message switching systems: an exponential, single-server queuing system with finite storage capacity, constant arrival rate, and queue-length-dependent service time. We consider cases in which the expected service time consists of a constant plus a term that grows linearly or logarithmically with the queue length. We show that the performance of this system -- as characterized by the expected number of customers in the system, the expected time in the system, and the rate of missed customers -- can undergo a sudden collapse as the result of small changes in the arrival rate, the overhead rate, or the queue capacity. The system has the interesting property that increasing the queue capacity can decrease performance. In addition to equlibrium results, we consider the dynamic behavior of the model. We show that the system tends to operate in either of two quasi-stable modes of operation -- one with low queue lengths and one with high queue lengths. System behavior is characterized by long periods of operation in both modes with abrupt transitions between them. We point out that the performance of a saturated system may be improved by dynamic operating procedures that return the system to the low mode. (Author)

Senddout page deciding mechanism

Abstract: PURPOSE:To reduce the occurring frequency for the page fault and thus to decrease the overhead in the virtual memory system applying the paging system, by giving the periodicity to the page to be sent out.