AN OPTICALLY-TRIGGERED I-RTD HYBRID THz OSCILLATOR DESIGN

2007 ◽  
Vol 17 (02) ◽  
pp. 339-353
Author(s):  
DWIGHT WOOLARD ◽  
WEIDONG ZHANG ◽  
ELLIOTT BROWN ◽  
BORIS GELMONT ◽  
ROBERT TREW
Keyword(s):  
Photon Flux ◽  
Practical Implementation ◽  
Transient Phase ◽  
Large Signal ◽  
Band Engineering ◽  
Tunneling Diode ◽  
Hole Charge ◽  
Two Phases ◽  
Performance Results ◽  
Optical Triggering

A design and analysis study is presented for a new optically-triggered (OT) interband resonant-tunneling-diode (I-RTD) device that has potential for generating terahertz (THz) frequency oscillations and achieving enhanced output power levels under pulsed operation. The proposed device utilizes novel nanoscale mechanisms to achieve externally driven oscillations that consist of two phases – i.e., an initial transient phase produced by a natural Zener (interband) tunneling process and a second discharging transient phase induced by optical annihilation of stored hole-charge by externally-injected photon flux. The specific focus of this paper will be on an OT-I-RTD oscillator that utilizes In 1- x Ga x As / GaSb y As 1- y hetero-systems and the application of band-engineering to enable triggering by 1.55 μm laser technology. The paper presents performance results for the hybrid circuit design, along with a practical implementation strategy for integrating the optical triggering and an analysis of the heating induced during large signal operation.

Crowd Planning and Preparation

2019 ◽  
Author(s):  
William O’Toole ◽  
Dr Stephen Luke ◽  
Travis Semmens ◽  
Dr Jason Brown ◽  
Andrew Tatrai
Keyword(s):  
Life Safety ◽  
Contingency Planning ◽  
Practical Implementation ◽  
Military Operations ◽  
Safety Issues ◽  
Crowd Management ◽  
Planning Methods ◽  
Risk Areas ◽  
Two Phases ◽  
And Control

This chapter reviews planning methods and practices. Significant work has been published and used for long periods on planning methods. Preplanning is essential due to the life safety factors that a crowd can develop in situ. Planning can be considered in two phases. Information and background planning essential to communicate facts and identify risk areas in crowd management and operational planning. This then provides resourcing and contingency planning once the operation is in place. Like military operations both phases are important, however in many crowd situations operational and contingency planning is given less scrutiny. This is because the plans are normally scrutinised by authorities, councils, government, venue or land owners and they are more comfortable with pre-information type plans that inform them of the context background and communication flows. How the crowds are managed by security contractors is not usually an area they are experienced in, hence less attention is paid to these areas. The aim of this chapter is to provide enough knowledge for all event stakeholders to review and discuss practical implementation issues in security deployment and control. Planning and preparation requires an increased focus for crowd management because the emerging behaviour from the collective requires more options to be considered and prepared for. As crowds can cause life safety issues and because agents and systems can interact to exaggerate interactions and responses quickly, preparation and contingency planning is vital. Crowd risk assessments have to be conducted to understand and communicate the magnitude of the problems that can occur. If the consequences of the crowd activity are significant to the risk appetite of the organiser then response methods and measures should be developed and implemented. An example of this would be preparing additional signage, barriers and guards to divert pedestrians away or around potential bottlenecks when the flow becomes too congested.

scholarly journals A Proposal for Evading the Measurement Uncertainty in Classical and Quantum Computing: Application to a Resonant Tunneling Diode and a Mach-Zehnder Interferometer

2019 ◽  
Vol 9 (11) ◽  
pp. 2300 ◽  
Author(s):  
Devashish Pandey ◽  
Laura Bellentani ◽  
Matteo Villani ◽  
Guillermo Albareda ◽  
Paolo Bordone ◽  
...  
Keyword(s):  
Resonant Tunneling ◽  
Electrical Current ◽  
Resonant Tunneling Diode ◽  
Zehnder Interferometer ◽  
Practical Implementation ◽  
State Reduction ◽  
Mean Values ◽  
Quantum Uncertainty ◽  
Tunneling Diode ◽  
Mach Zehnder Interferometer

Measuring properties of quantum systems is governed by a stochastic (collapse or state-reduction) law that unavoidably yields an uncertainty (variance) associated with the corresponding mean values. This non-classical source of uncertainty is known to be manifested as noise in the electrical current of nanoscale electron devices, and hence it can flaw the good performance of more complex quantum gates. We propose a protocol to alleviate this quantum uncertainty that consists of (i) redesigning the device to accommodate a large number of electrons inside the active region, either by enlarging the lateral or longitudinal areas of the device and (ii) re-normalizing the total current to the number of electrons. How the above two steps can be accommodated using the present semiconductor technology has been discussed and numerically studied for a resonant tunneling diode and a Mach-Zehnder interferometer, for classical and quantum computations, respectively. It is shown that the resulting protocol formally resembles the so-called collective measurements, although, its practical implementation is substantially different.

scholarly journals The GRT Planning System: Backward Heuristic Construction in Forward State-Space Planning

2001 ◽  
Vol 15 ◽  
pp. 115-161 ◽  
Author(s):  
I. Refanidis ◽  
I. Vlahavas
Keyword(s):  
State Space ◽  
Intermediate State ◽  
Forward Direction ◽  
Planning System ◽  
Search Process ◽  
Space Planning ◽  
Two Phases ◽  
Performance Results ◽  
Domain Independent ◽  
State Space Planning

This paper presents GRT, a domain-independent heuristic planning system for STRIPS worlds. GRT solves problems in two phases. In the pre-processing phase, it estimates the distance between each fact and the goals of the problem, in a backward direction. Then, in the search phase, these estimates are used in order to further estimate the distance between each intermediate state and the goals, guiding so the search process in a forward direction and on a best-first basis. The paper presents the benefits from the adoption of opposite directions between the preprocessing and the search phases, discusses some difficulties that arise in the pre-processing phase and introduces techniques to cope with them. Moreover, it presents several methods of improving the efficiency of the heuristic, by enriching the representation and by reducing the size of the problem. Finally, a method of overcoming local optimal states, based on domain axioms, is proposed. According to it, difficult problems are decomposed into easier sub-problems that have to be solved sequentially. The performance results from various domains, including those of the recent planning competitions, show that GRT is among the fastest planners.

scholarly journals High Potassium and Low Sodium Contractures in Sheep Cardiac Muscle

1971 ◽  
Vol 58 (5) ◽  
pp. 483-510 ◽  
Author(s):  
W. R. Gibbons ◽  
H. A. Fozzard
Keyword(s):  
Cardiac Muscle ◽  
Calcium Concentration ◽  
Sodium Concentration ◽  
Transient Phase ◽  
Extracellular Solution ◽  
High Potassium ◽  
Require Time ◽  
Low Sodium ◽  
Steady Level ◽  
Two Phases

Contractures develop in sheep atrial trabeculae if Tyrode's solution is rapidly replaced by a solution containing elevated potassium, reduced sodium, or both. Two phases of the contracture can be identified on the basis of differences in physiological behavior: a rapid and transient phase that predominates during the first few seconds of the contracture, and a slowly developed phase that is responsible for the steady level of tension reached later in the contracture. The transient phase is particularly prominent if the muscle is stimulated rapidly before the contracture, and reduced or absent if the muscle is not stimulated or if calcium is not present before the contracture. Recovery of the transient phase after a contracture parallels the recovery of twitches. This transient phase appears to reflect the depolarization-induced release of activator (calcium) from an internal store, possibly the same store that is involved in the normal contraction. The slowly developed tension is dependent on the contracture solution used, and is decreased if the calcium concentration is reduced or if the sodium concentration is increased. It does not depend on conditions before the contracture and does not require time to recover. This phase of the contracture may be due to entry of calcium from the extracellular solution.

scholarly journals Scene Classification for Sports Video Summarization Using Transfer Learning

Sensors ◽  
2020 ◽  
Vol 20 (6) ◽  
pp. 1702 ◽  
Author(s):  
Muhammad Rafiq ◽  
Ghazala Rafiq ◽  
Rockson Agyeman ◽  
Gyu Sang Choi ◽  
Seong-Il Jin
Keyword(s):  
Data Augmentation ◽  
Video Summarization ◽  
Performance Comparison ◽  
Practical Implementation ◽  
Scene Classification ◽  
Advertising Agencies ◽  
Sports Video ◽  
Performance Results ◽  
Implementation Gaps

This paper proposes a novel method for sports video scene classification with the particular intention of video summarization. Creating and publishing a shorter version of the video is more interesting than a full version due to instant entertainment. Generating shorter summaries of the videos is a tedious task that requires significant labor hours and unnecessary machine occupation. Due to the growing demand for video summarization in marketing, advertising agencies, awareness videos, documentaries, and other interest groups, researchers are continuously proposing automation frameworks and novel schemes. Since the scene classification is a fundamental component of video summarization and video analysis, the quality of scene classification is particularly important. This article focuses on various practical implementation gaps over the existing techniques and presents a method to achieve high-quality of scene classification. We consider cricket as a case study and classify five scene categories, i.e., batting, bowling, boundary, crowd and close-up. We employ our model using pre-trained AlexNet Convolutional Neural Network (CNN) for scene classification. The proposed method employs new, fully connected layers in an encoder fashion. We employ data augmentation to achieve a high accuracy of 99.26% over a smaller dataset. We conduct a performance comparison against baseline approaches to prove the superiority of the method as well as state-of-the-art models. We evaluate our performance results on cricket videos and compare various deep-learning models, i.e., Inception V3, Visual Geometry Group (VGGNet16, VGGNet19), Residual Network (ResNet50), and AlexNet. Our experiments demonstrate that our method with AlexNet CNN produces better results than existing proposals.

scholarly journals Generalized PI Sliding Mode Control of a Large-Signal 'Boost' Converter Model: Simulation and Practical Implementation

2004 ◽  
Vol 37 (21) ◽  
pp. 487-492
Author(s):  
Mario Spinetti-Rivera ◽  
Orlando Ostos-Roa ◽  
Hebertt Sira-Ramírez ◽  
Richard Marquez
Keyword(s):  
Sliding Mode Control ◽  
Sliding Mode ◽  
Model Simulation ◽  
Boost Converter ◽  
Practical Implementation ◽  
Large Signal ◽  
Mode Control

scholarly journals Efficient compilation of algebraic effect handlers

2021 ◽  
Vol 5 (OOPSLA) ◽  
pp. 1-28
Author(s):  
Georgios Karachalias ◽  
Filip Koprivec ◽  
Matija Pretnar ◽  
Tom Schrijvers
Keyword(s):  
Programming Language ◽  
Experimental Evaluation ◽  
Practical Implementation ◽  
Competitive Performance ◽  
Performance Gap ◽  
Runtime Support ◽  
Two Phases ◽  
Core Language

The popularity of algebraic effect handlers as a programming language feature for user-defined computational effects is steadily growing. Yet, even though efficient runtime representations have already been studied, most handler-based programs are still much slower than hand-written code. This paper shows that the performance gap can be drastically narrowed (in some cases even closed) by means of type-and-effect directed optimising compilation. Our approach consists of source-to-source transformations in two phases of the compilation pipeline. Firstly, elementary rewrites, aided by judicious function specialisation, exploit the explicit type and effect information of the compiler’s core language to aggressively reduce handler applications. Secondly, after erasing the effect information further rewrites in the backend of the compiler emit tight code. This work comes with a practical implementation: an optimising compiler from Eff, an ML style language with algebraic effect handlers, to OCaml. Experimental evaluation with this implementation demonstrates that in a number of benchmarks, our approach eliminates much of the overhead of handlers, outperforms capability-passing style compilation and yields competitive performance compared to hand-written OCaml code as well Multicore OCaml’s dedicated runtime support.

Securing Data Storage By Extending Role-Based Access Control

2013 ◽  
Vol 3 (4) ◽  
pp. 28-37 ◽  
Author(s):  
Mamoon Rashid ◽  
Er. Rishma Chawla
Keyword(s):  
Access Control ◽  
Organizational Structure ◽  
Data Storage ◽  
Practical Implementation ◽  
Role Based Access Control ◽  
Security Community ◽  
Cloud Server ◽  
Role Based ◽  
Administrative Expenses ◽  
Performance Results

Role-based access control (RBAC) models have generated a great interest in the security community as a powerful and generalized approach to security management and ability to model organizational structure and their capability to reduce administrative expenses. In this paper, the authors highlight the drawbacks of RBAC models in terms of access control and authorization and later provide a more viable extended-RBAC model, which enhances and extends its powers to make any Cloud Server more secure by adding valuable constraints. Later the Blobs are stored on cloud server which is then accessed by the end users via this Extended RBAC model. The authors describe a practical implementation of the proposed extended RBAC based architecture and discuss the performance results with its base models. The authors later show how the users with different premiums can access this architecture in a better way and also how the unknown users for this architecture can be denied the usage of services by adding valuable constraints.

Influence of Temperature Change on Spontaneous Locomotor Activity and Oxygen Consumption of Atlantic Salmon, Salmo salar, Acclimated to Two Temperatures

1969 ◽  
Vol 26 (1) ◽  
pp. 93-109 ◽  
Author(s):  
R. H. Peterson ◽  
J. M. Anderson
Keyword(s):  
Oxygen Consumption ◽  
Atlantic Salmon ◽  
Spontaneous Activity ◽  
Temperature Change ◽  
Test Temperature ◽  
Rapid Change ◽  
Standard Metabolic Rate ◽  
Transient Phase ◽  
Similar Test ◽  
Two Phases

Measurements of the effect of rapid change in temperature on the spontaneous activity and oxygen consumption were made on Atlantic salmon underyearlings acclimated to 6 or 18 C. The new levels of imposed temperature ranged from 6 to 30 C for both acclimations. At similar test temperatures the calculated standard metabolic rate of the fish acclimated to 6 C was higher than that of the fish acclimated to 18 C, up to about 23 C, where the two curves relating oxygen consumption and temperature intersect. Spontaneous activity could be separated into two phases, a transient phase occurring during the actual period of temperature change, and a stabilized phase. The transient phase was characterized by a peak in activity which was found to be correlated with the rate, rather than the amount, of the temperature change. In general, the peak was higher for fish acclimated to 18 C. The relation between activity in the stabilized phase and test temperature was characterized by a plateau or maximum in the general region of the previously determined selected temperature. Except at the coldest test temperature (6 C), the fish acclimated to 6 C were more active in the stabilized phase than were the fish acclimated to 18 C at similar test temperatures. Complete acclimation for both metabolism and activity, between 6 and 18 C, requires about 2 weeks, regardless of the direction of the temperature change.

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