Improving parallel program performance using critical path analysis

A programming tool that performs analysis of critical paths for parallel programs has been developed. This tool determines the critical path for the program as scheduled onto a parallel computer with P processing elements, the critical path for the program expressed as a data flow graph (when maximal parallelism can be expressed), and the minimum number of processing elements (P_opt) needed to obtain maximum program speedup. Experiments were performed using several versions of a Gaussian elimination program to examine how speedup varied with changes in granularity and critical path length. These experiments showed that when the available numer of processing elements P < P_opt, increasing granularity improved program speedup more than reducing (the data flow graph's) critical path length, whereas when P ≥ P_opt, increasing granularity degraded program speedup while reducing critical path length improved program speedup

CAD study of linear tapered slot antenna

Linear Tapered Slot Antenna (LTSA) is an attractive candidate as a radiating element in frequency scanning arrays. LTSA element backed by a rectangular cavity had been investigated and is proven to posses various physical design parameters suitable to optimize its performance. This study is focused on the feed position variation to optimize the performance while maximum of the current density variation is maintained in the slot region. It was observed that if the stub base of the microstrip feed structure is located in the middle of the slot region, current maximum can be obtained within the slot region at the expense of smaller return loss, contrary to the previously obtained optimization where the base of the stub was on the side of the slot line region. Furthermore, if the rectangular cavity is replaced by a circular cavity, then there is a slight increase in the bandwidth and a small drop in the return loss. When two LISA elements are placed back to back and excitation is achieved via strip line, rather than a single element microstrip excitation, circular cavity backed radiating elements could be tuned to obtain higher return loss. The strip line excitation also caused the decrease in the bandwidth. The mode structure excited in the circular cavity has to be studied further as well as its effects of the resonance frequency of the LTSA

Programming enviroments for parallel programming

Programming environments are used to bridge the gap between actual computers ad developement of their application programs. Most parallel programming environments currently in use focus on a specific parallel programming tool. This paper examines programming environments. language, tools, and techniques used for programming of parallel computers.In this paper, several topics are examined. First, a brief survey of parallel computer architectures and typical application programs is performed. Then, a survey of available environments, languages, and tools is conducted to determine how parallel programming is currently performed. Finally, by considering architectures, applications, and environments, an attempt is made to find desirable characteristics for a parallel programming environment and a useful set of parallel programming tools

Consumer Responses to GM Foods: Why are Americans so Different?

Consumer/Household Economics, Food Consumption/Nutrition/Food Safety,

PARENTHOOD, COVID-19, AND WORK OUTCOMES IN THE DOD

When the COVID-19 pandemic hit the United States around March 2020, it changed the landscape of the work environment, and there was a sudden shift from in-person office work to a substantial portion of the population conducting their jobs remotely. My study evaluates how these changes affected the Marine Corps’ critical resource—their personnel. By combining Marine Corps demographic data with K-12 public school closures data across the United States at the county level, I used four separate performance metrics to estimate the effects that school closures had on productivity among Marines. When the Marine Corps allowed parents the time to take care of their children, I found that it had a positive relationship between remote work and performance when looking at proficiency scores. My study also concluded that the population that suffered from school closures when compared to their counterparts were female Marines with children, when examining the impact on Combat Fitness Test scores. I recommend that the Marine Corps continue allowing Marines with children the flexibility to maintain a healthy work-life balance and find ways to lessen the burden when unforeseen childcare requirements arise. My analysis demonstrates that policies that provide more freedom for Marines to maintain a healthy work-life balance do not negatively affect a Marine’s performance. Creating new policies to continue the era of remote work in the Marine Corps can benefit the productivity of Marines.Major, United States Marine CorpsApproved for public release. Distribution is unlimited

An apartment house in Westgate-West for M.I.T. personnel, M.I.T., Cambridge, Massachusetts

Thesis (B. Arch.)--Massachusetts Institute of Technology, Dept. of Architecture, 1954.MIT copy bound with: A state library building for Louisiana / Edward Blakewood, III [1954] Accompanying drawings held by MIT Museum.Includes bibliographical references (leaf [19]).Tsun Wu W. Kwan.B.Arch

Cross-Layer Optimization of Fast Video Delivery in Cache-Enabled Relaying Networks

This paper investigates the cross-layer optimization of fast video delivery and caching for minimization of the overall video delivery time in a two-hop relaying network. The half-duplex relay nodes are equipped with both a cache and a buffer which facilitate joint scheduling of fetching and delivery to exploit the channel diversity for improving the overall delivery performance. The fast delivery control is formulated as a two-stage functional non-convex optimization problem. By exploiting the underlying convex and quasi-convex structures, the problem can be solved exactly and efficiently by the developed algorithm. Simulation results show that significant caching and buffering gains can be achieved with the proposed framework, which translates into a reduction of the overall video delivery time. Besides, a trade-off between caching and buffering gains is unveiled.Comment: 7 pages, 4 figures; accepted for presentation at IEEE Globecom, San Diego, CA, Dec. 201