Daisy Chaining Research Articles

Feasibility study of shielded diode detector for small field dosimetry.

Improved imaging techniques and modern radiotherapy treatment delivery in the treatment field are reduced to the precise size of the tumor, which necessitates the need for small-field dosimetry. Dosimetry in small-field dosimetry is challenging because most of the available code of practice for dosimetry is based on the cavity theory concept. Some small-sized detectors show good spatial resolution and sensitivity. Of the available small detectors, the diamond detector's performance is remarkably good. Most of the centers for radiotherapy lack diamond detectors. In this situation, if a diode detector is available, we can use it for small-field dosimetry by applying the Daisy Chaining method correction methods. In this study, the diode detector's response is not over-responding because of the defective diode. So this diode cannot be used for further measurements, and we have to regularly check the performance of the diode before using it for measurements.

Somatic Liver Knockout (SLiK): A Quick and Efficient Way to Generate Liver-Specific Knockout Mice Using Multiplex CRISPR/Cas9 Gene Editing.

Somatic liver knockout (SLiK) is a method developed to rapidly generate a liver-specific knockout of one or several genes. This technique combines the strengths of CRISPR/Cas9 gene editing and hydrodynamic tail-vein injection, a simple in vivo method for transfection of hepatocytes, to harness the powerful selection pressure of tyrosinemic livers to replace host hepatocytes with any desired gene deletion. In this protocol, we will describe sgRNA design and cloning, hydrodynamic tail-vein injection of targeting constructs, and screening and validation methods for efficient in vivo gene editing. © 2020 by John Wiley & Sons, Inc. Support Protocol 1: sgRNA design Support Protocol 2: sgRNA construction: daisy chaining multiple sgRNAs Basic Protocol: Delivery of DNA by hydrodynamic tail-vein injection and liver repopulation of edited hepatocytes Support Protocol 3: Validation of CRISPR/Cas9 cutting in vivo.

A method of measuring the field output factor based on daisy–chaining

Objective improve the accuracy of the measurement results by using the field output factor measurement method based on daisy-chaining. Methods The Varian Edge Accelerator 6 MV X-ray data were measured using the IBA CC13 ionization chamber, IBA CC01 ionization chamber, IBA Razor semiconductor detector, IBA EFD semiconductor detector and Gafchromic EBT3 film, respectively. Results Compared with the daisy-chaining measurement method, the results obtained by the conventional measurement method using CC13 were smaller. The deviation value was 16.71% in the 1 cm × 1 cm field. The measurement results in a larger field via CC01 were bigger with a deviation of 8.39% in the 40 cm × 40 cm filed. The measurement results via Razor in a larger field were larger with a deviation of 9.40% in the 40 cm × 40 cm field. The measurement results were similar between EFD and Razor with a deviation of 9.14% in the 40 cm × 40 cm field. The results of the film measurement were equivalent to those obtained from the daisy-chaining method in a field of> 1 cm × 1 cm with a deviation within 1.60%, whereas the deviation was increased to 3.13% in the 1 cm × 1 cm field. The results were consistent with daisy-chaining measurement if the 3 cm × 3 cm or 4 cm × 4 cm fields were selected as the intermediate fields with the maximum deviation of 0.29%. Conclusions For the detectors with changing response along with the field size, daisy-chaining measurement method can be utilized to extend the measurement range and improve the accuracy of the measurement results. Key words: Daisy-Chaining; Output factor; Measurement method

EP-1721: Small field output factors with PTW diode 60018 with and without daisy chaining, validated by film

EP-1721: Small field output factors with PTW diode 60018 with and without daisy chaining, validated by film

Measurement of Total Scatter Factor for Stereotactic Cones with Plastic Scintillation Detector.

Advanced radiotherapy modalities such as stereotactic radiosurgery (SRS) and image-guided radiotherapy may employ very small beam apertures for accurate localized high dose to target. Accurate measurement of small radiation fields is a well-known challenge for many dosimeters. The purpose of this study was to measure total scatter factors for stereotactic cones with plastic scintillation detector and its comparison against diode detector and theoretical estimates. Measurements were performed on Novalis Tx™ linear accelerator for 6MV SRS beam with stereotactic cones of diameter 6 mm, 7.5 mm, 10 mm, 12.5 mm, and 15 mm. The advantage of plastic scintillator detector is in its energy dependence. The total scatter factor was measured in water at the depth of dose maximum. Total scatter factor with plastic scintillation detector was determined by normalizing the readings to field size of 10 cm × 10 cm. To overcome energy dependence of diode detector for the determination of scatter factor with diode detector, daisy chaining method was used. The plastic scintillator detector was calibrated against the ionization chamber, and the reproducibility in the measured doses was found to be within ± 1%. Total scatter factor measured with plastic scintillation detector was 0.728 ± 0.3, 0.783 ± 0.05, 0.866 ± 0.55, 0.885 ± 0.5, and 0.910 ± 0.06 for cone sizes of 6 mm, 7.5 mm, 10 mm, 12.5 mm, and 15 mm, respectively. Total scatter factor measured with diode detector was 0.733 ± 0.03, 0.782 ± 0.02, 0.834 ± 0.07, 0.854 ± 0.02, and 0.872 ± 0.02 for cone sizes of 6 mm, 7.5 mm, 10 mm, 12.5 mm, and 15 mm, respectively. The variation in the measurement of total scatter factor with published Monte Carlo data was found to be −1.3%, 1.9%, −0.4%, and 0.4% for cone sizes of 7.5 mm, 10 mm, 12.5 mm, and 15 mm, respectively. We conclude that total scatter factor measurements for stereotactic cones can be adequately carried out with a plastic scintillation detector. Our results show a high level of consistency within our data and compared well with published data.

Frequency-Translational Quadrature-Hybrid Receivers for Very-Low-Noise, Frequency-Agile, Scalable Inter-Band Carrier Aggregation

A frequency-translational quadrature-hybrid receiver is proposed that achieves wideband input matching for a reflective low-noise-amplifier input impedance and enables the realization of wideband, concurrent receivers. Frequency-agile, inter-band carrier aggregation is realized from a single antenna through RF signal sharing and quadrature-hybrid-coupler daisy chaining. A 1.1 V 65 nm CMOS prototype chip is demonstrated that has a sub-1 dB minimum NF, a 12 MHz to 70 MHz RF bandwidth, a +8 dBm $IIP_{3}$ , and a −15 dBm $B_{1dB}$ and consumes <58 mW per channel. The prototypes have been integrated into a demonstration system that features 4-band inter-band carrier aggregation with modulated carriers placed between 0.69 and 2.1 GHz and received with an EVM <2.8%.

Modelling and Daisy Chaining Control Allocation of a Multirotor Helicopter with a Single Tilting Rotor

This paper presents the development and implementation of a single tilting rotor multirotor helicopter. A single tilting rotor multirotor helicopter is proposed that allows for decoupled lateral acceleration and attitude states. A dynamics model of the proposed multirotor helicopter is established to enable control system development. A control system architecture and daisy chaining-based control allocation scheme is developed and implemented. The control architecture facilitates the control of decoupled lateral accelerations and attitudes. Further, a computational and experimental analysis is undertaken and offers evidence that the proposed multirotor helicopter and control system architecture enables the multirotor helicopter to achieve lateral accelerations without requiring attitude actuation.

Who is minding the bibliography? Daisy chaining, dropped leads, and other bad behavior using examples from the dog bite literature

Who is minding the bibliography? Daisy chaining, dropped leads, and other bad behavior using examples from the dog bite literature

INDI Control with Direct Lift for a Tilt Rotor UAV

The benefits of adding direct lift control capabilities to a high aspect ratio, low wing load, tilt rotor UAV within an Incremental Nonlinear Dynamic Inversion framework are presented in this paper. The primary motivation is the need for some gust alleviation scheme to mitigate the large sensitivity to turbulence of light weight, low wing loaded aircraft, such as small tilt rotor UAVs, designed to operate at low speeds. The highly nonlinear dynamic model of the tilt rotor aircraft was developed using the component buildup method associated with the lifting line theory. The effector redundancy was managed through a control allocation module based on the daisy chaining strategy. Classic aerodynamic effectors are used in forward flight, whereas thrust vectoring is required in hover. During transition phases aerodynamic effectors are preferred over thrust vectoring, which intervenes upon saturation of aerodynamic effectors or when they become ineffective at low speed. Since dynamic inversion exhibits poor performance in turbulence due to its intrinsic aggressive use of controls, direct lift is proposed in this paper for gust alleviation, improving performance and reducing overall control effort. Direct lift has been achieved adopting full span flaperons: symmetric deflection generates lift whereas differential deflection produces roll. Direct lift control has the benefit of providing direct, thus fast control of the vertical degree of freedom, whereas conventional elevators try to minimize vertical speed fluctuations through pitch attitude changes, resulting in considerable lags. Another desirable feature of direct lift control for tilt rotor application is the closer commonality between the forward and hover flight regimes, by providing direct control of the vertical motion in forward flight, as provided by thrust vectoring in hover. A comparison was done between similar control law schemes with and without direct lift. Simulations proved the effectiveness of the approach in improving reference tracking in presence of turbulence and reducing control effort.

A TCP/IP-based constant-bit-rate file transfer protocol and its extension to multipoint data delivery

We present a new TCP/IP-based file transfer protocol which enables high-speed daisy-chain transfer. By using this protocol, we can send a file to a series of destination hosts simultaneously because intermediate hosts relay received file fragments to the next host. We achieved daisy-chain file transfer from Japan to Europe via USA at about 800Mbps by using a prototype. The experimental result is also reported. A total link length of a data delivery network can be reduced by daisy chaining, so it enables cost-effective international data sharing.

Binding of the ionic liquid cation 1-alkyl-3-methylimidazolium to p-tetranitrocalix[4]arene probed by fluorescent indicator displacement

Acridine orange (AO) was used as a fluorescent probe molecule to study the encapsulation of an alkylimidazolium cation from a water-soluble ionic liquid (IL) within two cavitand species, p-tetranitrocalix[4]arene (1) and calix[4]resorcinarene (2), both in alkaline aqueous media. The addition of IL to the preformed [1·AO] adduct resulted in significantly increased fluorescence due to the expulsion of AO from the inclusion complex to the aqueous phase by competitive recognition of the 1-alkyl-3-methylimidazolium cation ([C(n)mim](+), n = 4 and 6) by 1. Conversely, the fluorescence signal dropped upon the addition of IL to the [2·AO] host-guest complex due to unfavorable binding between [C(n)mim](+) and 2. The formation of these postulated adducts is corroborated using ab initio calculations, which also provide evidence for the location of [bmim](+) at the lower external rim of [2·AO], providing an explanation for the observed luminescence quenching in the latter case. These results point to a number of different paths for exploration, ranging from the fluorescence monitoring of IL contamination in groundwater to the "daisy chaining" of macrocyles toward supramolecular ionic networks. They also broadly encourage the exploration of ILs in host-guest-based optical and mass spectrometric sensory systems.

A fully automated non-external marker 4D-CT sorting algorithm using a serial cine scanning protocol

Current 4D-CT methods require external marker data to retrospectively sort image data and generate CT volumes. In this work we develop an automated 4D-CT sorting algorithm that performs without the aid of data collected from an external respiratory surrogate. The sorting algorithm requires an overlapping cine scan protocol. The overlapping protocol provides a spatial link between couch positions. Beginning with a starting scan position, images from the adjacent scan position (which spatial match the starting scan position) are selected by maximizing the normalized cross correlation (NCC) of the images at the overlapping slice position. The process was continued by ‘daisy chaining’ all couch positions using the selected images until an entire 3D volume was produced. The algorithm produced 16 phase volumes to complete a 4D-CT dataset. Additional 4D-CT datasets were also produced using external marker amplitude and phase angle sorting methods. The image quality of the volumes produced by the different methods was quantified by calculating the mean difference of the sorted overlapping slices from adjacent couch positions. The NCC sorted images showed a significant decrease in the mean difference (p < 0.01) for the five patients.

Vision-based localization of a wheeled mobile robot for greenhouse applications: A daisy-chaining approach

The Euclidean position and orientation of a wheeled mobile robot (WMR) is typically required for autonomous selection and control of agricultural operations in a greenhouse. A vision-based localization scheme is formulated as a desire to identify the position and orientation of a WMR navigating in a greenhouse by utilizing the image feedback of the above-the-aisle targets from an on-board camera. An innovative daisy chaining strategy is used to find the local coordinates of the above-the-aisle targets in order to localize a WMR. In contrast to typical camera configurations used for vision-based control problems, the localization scheme in this paper is developed using a moving on-board camera viewing reseeding targets. Multi-view photogrammetric methods are used to develop relationships between different camera frames and WMR coordinate systems. Experimental results demonstrate the feasibility of the developed geometric model.

Modified Pseudoinverse Redistribution Methodsfor Redundant Controls Allocation

Introduction I N recent years, control allocation problems have been intensively studied following the work of Durham.1−3 There are several solution methods: direct control allocation,1−3 daisy chaining,4 a linearprogramming (LP) method,5−6 a quadratic-programming (QP) method,7−11 and a pseudoinverse-redistribution (PIR) method.10−13 In this Note, a PIR method is discussed. A pseudoinverse has been used as a selector or a distributor.14 Shtessel et al. applied a pseudoinverse to the control allocation problem for a tailless aircraft.15 However, it is fixed, and it does not consider the control surfaces’ limits. Virnig and Bodden developed a PIR method for a short takeoff and vertical landing aircraft and then demonstrated the algorithm by means of a simulator.12 The PIR method repeats the process of calculating a pseudoinverse and a control vector by setting the saturated elements of a control vector to their limit values until a solution is obtained or there is no unsaturated element. Bordignon and Bessolo developed a modified method and applied it to the X-35 aircraft’s control allocation problem.16 Although the PIR method sets the saturated control elements to their limit values, the modified method selects only one saturated element and sets it to its limit value during the redistribution process. The purpose of this Note is to propose other modified methods and to compare them with the conventional PIR method and Bordignon and Bessolo’s method. A different selection of one saturated element results in a difference in performance. For this purpose, two different selections are proposed. The performance metrics of concern are the calculation times, the percentage of times that a method converges to an optimal solution, and the characteristics of the errors between the optimal solutions and the redistributed solutions. Numerical examples are presented for comparisons.

Fuzzy Logic Arbiters for Multiple-Bus Multiprocessor Systems

This paper describes and evaluates the use of fuzzy logic arbiters for multiple-bus shared memory multiprocessor system. Multiple-bus systems allow multiple and simultaneous bus transfer in addition to a high degree of fault tolerance. In such systems, arbiters are used to resolve conflicts to system resources, which are the shared memory modules and the buses. Typically, these conflicts are resolved by using two-stage arbitration schemes that employ policies such as random choice, daisy chaining, round-robin, etc. A new way of implementing these arbiters is the use of fuzzy logic to resolve resource request conflicts based on the system state and performance variables. This paper describes a new technique for implementation of fuzzy logic in the system arbiters and presents a simulation program that evaluates the system performance. The program is coded in such a way as to accommodate any arbitration scheme, from which the fixed priority and fuzzy priority have been implemented. Parameters affecting multiple-bus system performance are considered and used as inputs to the fuzzy arbiters. The inputs are fuzzified by using appropriate membership functions, and rules have been defined in such a way as to increase and distribute evenly the acceptance probability of each processor in the system. Results from the simulation program using a prioritized arbitration scheme are compared against other published results and show very close agreement. Furthermore, results show an increase in the acceptance probability of the processors using fuzzy arbiters.

Fast Implementation of Direct Allocation with Extension to Coplanar Controls

The direct allocation method is considered for the control allocation problem. The original method assumed that every three columns of the controls effectiveness matrix were linearly independent. Here, the condition is relaxed, so that systems with coplanar controls can be considered. For fast online execution, an approach using spherical coordinates is also presented, and results of the implementation demonstrate improved performance over a sequential search. Linearized state-space models of a C-17 aircraft and of a tailless aircraft are used in the evaluation. Oincreasethe reliability ofaircraft,cone gurations with a large numberofactuatorsandcontrolsurfacesareadvantageous.Recone gurable control laws may be used to exploit all of the available control power despite failures and damages. 1;2 Control allocation is the problem of distributing the control requirements among multiple actuators to satisfy the desired objectives while accounting for the limited range of the actuators. Although solutions exist for the control allocation problem, an issue of current interest is that of the feasibilityoftheirimplementationonexistingcomputersforaircraft with a large number of actuators. 3 The direct allocation approach 4i6 is based on the concept of the attainable moment set (AMS), which is the set of all of the moment vectors that are achievable within the control constraints. The methodofdirectallocation allowsoneto achieve100%oftheAMS, whereas some other approaches such as daisy chaining, pseudoinverse,and generalized inversesolutionshavebeen shown to achieve

An analysis of the destabilizing effect of daisy chained rate-limited actuators

The response of a rate-limited actuator will lag behind a rapidly changing command. This lag may destabilize the closed-loop system. When multiple actuators are arranged in a daisy chain this effect can be significantly worse. The cost of daisy chaining, in terms of lost stability margin, is estimated analytically and numerically. A comparison of a simple daisy chain with a simple "cooperative" control selector shows that the daisy chain may cause as much as 30/spl deg/ of additional phase lag.

Closed-form solutions to constrained control allocation problem

This paper describes the results of recent research into the problem of allocating several flight control effectors to generate moments acting on a flight vehicle. The results focus on the use of various generalized inverse solutions and a hybrid solution utilizing daisy chaining. In this analysis, the number of controls is greater than the number of moments being controlled, and the ranges of the controls are constrained to certain limits. The control effectors are assumed to be individually linear in their effects throughout their ranges of motion and independent of one another in their effects. A standard of comparison is developed based on the volume of moments or moment coefficients a given method can yield using admissible control deflections. Details of the calculation of the various volumes are presented. Results are presented for a sample problem involving 10 flight control effectors. The effectivenesses of the various allocation schemes are contrasted during an aggressive roll about the velocity vector at low dynamic pressure. The performance of three specially derived generalized inverses, a daisy-chaining solution, and direct control allocation are compared.

A simple analytical method for calculating temperature perturbations in a basin caused by the flow of water through thin, shallow-dipping aquifers

Fluid flow in sedimentary basins can be driven by a variety of mechanisms. Commonly, flow is localized in relatively thin aquifers or structures and often these permeable units may be approximated by a series of straight planar segments with shallow dip. A simple formula is derived that describes temperature perturbations in a straight aquifer segment with shallow dip. The temperature is determined everywhere along the segment if the flow rate and temperature at one point is known. “Daisy chaining” the solutions allows easy calculation of the temperature perturbation in a basin caused by fluid flow through a shallow-dipping network of linear fault and aquifer segments. The approach may find many applications but is here illustrated the a number of examples related to the origin of Mississippi Valley-type Pb Zn deposits. The cases considered emphasize the “salinity problem” encountered by models that hypothesize these deposits formed as the result of cross-basin hydrological flow.