Reciprocal Operation Research Articles

ПРОБЛЕМАТИКА МЕТОДІВ ОЦІНЮВАННЯ АНТЕН ЗІ ЗМЕНШЕНОЮ ЕФЕКТИВНОЮ ПОВЕРХНЕЮ РОЗСІЮВАННЯ ЗАСОБІВ РАДІОЕЛЕКТРОННОЇ РОЗВІДКИ ТА РАДІОЕЛЕКТРОННОЇ БОРОТЬБИ

The article analyses the relevance of well-known approaches to reducing radar visibility of signals intelligence and electronic warfare systems by reducing the effective scattering surfaces of their antenna systems based on the experience of the current Russian-Ukrainian war. The author has analysed known approximate methods used to calculate scattering of electromagnetic waves by antennas, and in particular, how integral and differential scattering surfaces can be calculated. The article provides simple formulas for estimating such values. The author proves that any reduction of the electromagnetic field re-radiated by weapons and military vehicles because of their specific shapes, use of radio-absorbing materials and coatings, etc. doesn't influence the scattering from their antenna systems. Challenging is the impossibility to avoid the above re-radiation, since according to the reciprocal operation principle, any antenna scatters at least half of the energy captured by it. Therefore, it makes sense to reduce the total or integral scattering capacity just a little bit. It can also be assumed that we can reduce the radar visibility of an antenna by replacing a linear polarization antenna with a circular polarization one. It will change the direction of wave reflection on the onboard radar sensor. The author recommends to apply miniaturized horn irradiators for their antenna systems in ground signals intelligence and electronic warfare stations provided that the performance characteristics are preserved by reducing overall dimensions, improving harmonization in antenna paths and reducing re-radiation from the antenna aperture. By selecting the amplitude and phase of the reflection coefficient in the feeder path, you can compensate for shadow and mode scattering and reduce it by 10–20 dB. The conducted study will further contribute to the development of an antenna design with a new small-sized irradiator and will make it possible to assess reduction of its effective scattering surface. Keywords: radar; pyramidal horn irradiator; reduction of effective scattering surface; radar visibility; electromagnetic wave diffraction.

Entering the world with notes: Reclaiming the practices of lecturing and note making

In this article we focus on note taking as a practice that is fundamental to (higher) education. We argue that note-taking should not primarily be regarded as a method that supports effective learning, but as formative of the student herself (making her attentive and granting possibilities for self-transformation). Hence it is a practice that has educational meaning in and of itself. It is a pedagogical form in its own right. We go on arguing that the practice of lecturing can itself be seen as a form of note taking and that both phenomena are not only closely related, but also that note making and lecturing consist of reciprocal operations. Studying on the basis of one’s notes comes down to the reverse operation the teacher had to perform when preparing her lessons. Moreover, thanks to making notes during a class students have a deeply embodied sense of what it means to generate and to construct new arguments and ideas.

DSP-based image real-time dehazing optimization for improved dark-channel prior algorithm

To solve the problem of non-real-time processing of image dehazing using traditional dark-channel prior algorithm, this work studies image real-time penetrating fog optimization technologies based on digital signal processor (DSP) devices. Using jointed optimization mechanism between algorithm and device, we can achieve real-time processing. During algorithm optimization, mean filter characterized low computation substitutes the guided filter which is the most complex in dark-channel algorithm for dehazing. In optimization of image processing task under the embedded device, we empirically construct two-step optimization strategy for raising speed of processing. Thereupon, the awful division calculation for DSP device is achieved approximately by multiplication after the reciprocal operation. We utilize the specified template which is considerably designed to realize mean filter. Thus, the division factor in the template can be calculated innovatively via shift instructions featured on DSP. The experimental results show that the optimization solution provided has realized real-time image dehazing processing for standard-definition and high-definition at frame rate of 25 fps over C6748 pure DSP device featured 456 MHz clock, at the same time the effect of penetrating fog is not remarkably degraded. The optimization methods or ideas can easily be transplanted to similar platform.

Mixed Fractional Integration and Differentiation as Reciprocal Operations

Mixed Fractional Integration and Differentiation as Reciprocal Operations

Sorumluluk ve Denetim Kavramları Üzerinden Havayolu Çalışanlarının İncelenmesi

<div><!--block-->This study scrutinizes types of work in the transition from Fordism to Post-Fordism within the scope of responsibility and control concepts. Responsibility and control are explored among the workers of an airline company operating in Izmir airport. Civil aviation, which is a developing industry in Turkey, is the ground to observe the reflections of technology in industrial relations and work process due to the fact that technology is adopted in civil aviation to a large extent. In addition, civil aviation, an area with a limited contribution of social science, is yet to be further explored in sociology. Phenomenological qualitative method was applied together within-depth interviews carried out with fifteen workers and almost two years of participant observation in the airport. It was found that intense use of technology puts signs in a circulation and generates simulation. Power and authority operate effectively in simulation, which results in a swirl of responsibility and control for workers. Responsibility is not unilateral control and it reflects structure and agency in reciprocal operation. About responsibility, relations with customers, personal qualities, attention and decision making themes emerged and about control, types of control,&nbsp; control as an experience and control chains themes emerged.&nbsp;</div>

Broadband LP01-LP02 mode converter for O-, E-, S-, C-, L-, and U-bands.

This paper proposes a novel all-optical fiber mode converter for mode conversion from LP01 to LP02 and vice versa. The mode converter is formed by connecting a single-mode fiber, a taper-core multi-mode fiber, and a few-mode fiber (FMF) together. The taper fiber core is designed to convert LP01 mode to LP02. The few-mode fiber is used to cut off the modes that are higher than LP02. It is shown that the proposed mode converter provides 20dB extinction ratio and low insertion loss in a very broad optical bandwidth of 200nm, from 1465 to 1665nm. By further optimizing the FMF radius only for each of the O-, E-, S-, C-, U-, etc. bands, the mode converter can apply to any band of interest with higher performance. It is found that the performance of the mode converter has a large tolerance to structural parameters. The mode converter has the same performance in reciprocal operation, i.e., LP02 to LP01.

Configuration Synthesis of Generalized Mechanism Based on Screw Theory

A mechanism composed of generalized links and kinematic pairs is defined as the generalized mechanism, which is capable of transforming motions and forces. It is an expansion of traditional rigid mechanisms and can better reflect the material characteristics. The constraint screw systems of limbs were constructed according to the screw description of generalized links and kinematic pairs. By using screw reciprocal operations, the kinematics screw can be obtained. In addition, the analysis method of kinematic characteristics was established. After that, the inverse-kinematics configuration synthesis method was proposed by inversing the mechanism kinematics analysis. Given the specified motion, the constraint screw system of generalized mechanism was obtained. The constraint screw system can be further decomposed and computed to get the limb kinematics screw systems. Accordingly, the kinematic limbs of the generalized mechanism were obtained. By permutating the kinematic limbs, the desirable configurations of generalized mechanism were obtained.

Pressure reciprocity calibration of a MEMS microphone.

This article reports the first use of the pressure reciprocity technique to calibrate a micro-electromechanical system (MEMS) microphone. This standardized primary calibration method is conventionally used to calibrate laboratory standard microphones. Results for the pressure reciprocity calibration of a MEMS microphone and two laboratory standard microphones are presented for the frequency range 100-10 000 Hz. Because the amplifier in the MEMS microphone package prevents reciprocal operation, this microphone was used only as a receiver of sound. A description of the procedure is presented along with checks of the measurement results and data regarding the uncertainties of these results.

Research and realisation of reciprocal electronic circuits for gas ultrasonic flow meter

The transit-time ultrasonic flow meters often show non-zero-flow rate when the flow is stationary due to the variations between transducers, which results in a zero-flow error. Moreover, the zero-flow error may change along with the measurement environment which causes the zero-drift error. The zero-flow error and zero-drift error will lead to false flow detection and influence the measurement stability at low velocities. Reciprocal operation theory has been proven to be an effective technique to eliminate zero-flow error. Therefore, reciprocal electronic circuits for gas ultrasonic flow meter are designed in this study. The circuits are first modelled in PSpice to validate its effectiveness. It is shown that both the zero-flow error and the zero drift are reduced significantly with the reciprocal circuits. Besides, the optimum matched resistor is determined by simulation. Second, three experiments are carried out to test the reciprocal circuits including transducers paired experiment, temperature test and flow calibration. Finally, it is verified that the reciprocal circuits can improve the measurement accuracy and stability for gas ultrasonic flow meter and the calibration results show that the gas ultrasonic flow meter (USM) with reciprocal circuits can achieve 1.0% measurement accuracy in 0.3-30 m/s.

A Scaling-Less Newton–Raphson Pipelined Implementation for a Fixed-Point Reciprocal Operator

The reciprocal is a widespread operation in digital signal processing architectures. A usual method consists in using the Newton–Raphson algorithm or its derivatives, either in floating or in fixed-point formats. With the former format, the standardized format of the mantissa makes the implementation easier, but for the fixed-point format there are many possibilities. This forces a design with scaling of the input in order to respect a predetermined work range. Having the input in a known range makes it possible to compute a first approximation with coefficients stored in memory blocks. With this method, it is hard to propose a “ready to use” IP for all the fixed-point formats. In this letter, a novel architecture, which does not require scaling, is proposed. This design is totally pipelined, ROM-less and can be directly used in any architecture. The implementation was optimized to reach a maximum clock frequency of 740 MHz on a Virtex-7 Field-Programmable Gate Array (FPGA).

Coherent manipulation of a solid-state artificial atom with few photons.

In a quantum network based on atoms and photons, a single atom should control the photon state and, reciprocally, a single photon should allow the coherent manipulation of the atom. Both operations require controlling the atom environment and developing efficient atom–photon interfaces, for instance by coupling the natural or artificial atom to cavities. So far, much attention has been drown on manipulating the light field with atomic transitions, recently at the few-photon limit. Here we report on the reciprocal operation and demonstrate the coherent manipulation of an artificial atom by few photons. We study a quantum dot-cavity system with a record cooperativity of 13. Incident photons interact with the atom with probability 0.95, which radiates back in the cavity mode with probability 0.96. Inversion of the atomic transition is achieved for 3.8 photons on average, showing that our artificial atom performs as if fully isolated from the solid-state environment.

Using micro-planes concrete damage model in discrete least squares meshless method for predicting the crack growth

In the present study, the author’s previously developed micro-planes concrete damage model has been implemented in the Discrete Least Squares Meshless method (DLSM) for assessment of the crack performance in concrete domains. DLSM is a true meshless method needing no partition in the local approximation as well as in the assembling of the local approximations in order to obtain a global solution. Instead it uses a collection of the un-structured nodal points in place of the elements and discretizes the governing differential equations with the discrete least squares approach. This can reduce considerably the pre-processing efforts of the calculations. However, DLSM like other meshless methods loses its efficiency when it is applied for the analysis of the solid domains dealing with the growing cracks. In recent years, some researchers have utilized some techniques to overcome this problem such as visibility, transparency and diffraction for precisely detecting the crack discontinuity in the case of a static non-growing crack, but these methods require some reciprocal corrective operations within each step of the calculation process extending the time of processing. In this study, however, a new, straightforward and general applicable method has been used for accommodating this issue using the advantages of the Moving Least Squares (MLS) shape functions constructed based on the Voronoi tessellation algorithm and micro-planes concrete damage constitutive model. Voronoi based MLS shape functions have been implemented for evaluating the crack effects accurately as a discontinuity during the analysis processing and micro-planes concrete damage approach used for proper detecting the crack growth trajectory. In the proposed method, the domain of interest is divided into the Voronoi cells based on the classical Voronoi tessellation approach, a cell for each node, and then the support domain of each node located inside the domain as well as on or near the crack faces is determined based on a neighboring criterion. During each step of the analysis for all the integration points, damages are computed according to the micro-planes concrete damage model and the crack path for the next step will be defined. After the end of the iterations in each step, both the stiffness tensor and internal load vector are modified based on the final stress fields obtained on and near the crack. The accuracy and efficiency of the proposed method have been investigated by solving some benchmark examples and comparing the obtained results with the analytical or valid finite element analyses’ results.

Efficiency of some voice coil transducers in low frequency reciprocal operations.

The feasibility of using different voice coil transducers in applications with reciprocal transducers of mechanical waves is investigated. It was speculated that voice coil transducers could be a more efficient alternative to piezoelectric transducers in low frequency ranges. Five different voice coil transducers, originally constructed for either transmission or reception, were characterized in both modes of operation. A piezoelectric ceramic disk was used for comparison between the transducer types. The results show that voice coils indeed can function as reciprocal transducers and that the most sensitive of the evaluated transducers is more efficient than the piezoelectric disk for low frequencies.

Electronic circuit design for reciprocal operation of transit-time ultrasonic flow meters

The reciprocal operation theory has been used in the circuit design of transit-time ultrasonic flow meters (USMs) to promote their zero flow performances. In this paper, the authors analyzed the transfer functions of the inter-conversion between acoustic and electric signals on each transducer, indicated that the equivalent load consistency for each transducer between the transmitting and the receiving phases would guarantee the transmitting and the receiving transfer functions equal, and thus guarantee the reciprocal operation of the USM system. In order to achieve the “load consistency” condition in practical systems with non-ideal parameters, a method of applying short pulse excitation and fixing the equivalent load in the “free oscillation period” of the transmitting transducer is proposed. Based on this method, several circuit designs are shown in the paper, the impedance preferences are also analyzed. Practical experiments done with these circuits show clear improvement in both promoting the accordance of the signals received in both directions and reducing the zero flow error in the measurement.

Obtaining Accurate Error Expressions and Bounds for Floating-Point Multiplicative Algorithms

Multiplicative Newton-Raphson and Goldschmidt algorithms are widely used in current processors to implement division, reciprocal, square root and square root reciprocal operations. Based on an initial approximation of a given accuracy, several iterations are performed until the required result accuracy is achieved. The number of iterations depends on the initial approximation and on the required accuracy. Each iteration consists of several multiplications. In this paper, we present an accurate error analysis that takes into account all the contributions to the final error and allows us to obtain error bounds for each iteration. These error bounds can be used to obtain optimal unit designs by reducing the size of the multiplier and, therefore, to reduce the area requirements. To show the usefulness of the error analysis, we compare the optimal multiplier size obtained from our error analysis with the multipliers in the floating-point division and square root units of some popular processors and we conclude that the multiplier size and its area can be reduced by, roughly, 10%. © 2013 The Author.

All-Fiber Broadband ${\rm LP}_{02}$ Mode Converter for Future Wavelength and Mode Division Multiplexing Systems

A novel broadband all-fiber LP <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">02</sub> mode converter is proposed and numerically analyzed. The converter is based on multimode interference in a multimode fiber (MMF) that interconnects a single-mode fiber (SMF) with a few-mode fiber, considered the transmission medium in future mode division multiplexing (MDM) systems. The proposed LP <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">02</sub> converter is reciprocal and polarization independent, and supports a very broad optical bandwidth of 150 nm with an over 20 dB extinction ratio, as well as an efficient coupling and easy connectivity as an all-fiber device. In a reciprocal operation, it performs mode filtering as well, therefore supporting mode demultiplexing. The dependence of the performance of the converter on the MMF length and core diameter is further investigated. The very broad bandwidth of the device renders it suitable for future transmission systems that need to combine MDM with wavelength division multiplexing targeting to achieve record transmission rates that cannot be reached with SMF transmission systems.

$e$-Plus Solutions for a Bilateral Arm Trainer With Wireless Sensor Networks

Bilateral arm training is a popular upper extremity exercise for patients after stroke. Conventional bilateral arm trainers such as sanding units are simply made by woods, and they cannot provide quantitative performance data for automatic assessments. Hence, continuous investigations are generally required for such reciprocal operations, and those procedures result in extra loads of caregivers. In this paper, wireless sensor network (WSN) approaches are employed to develop automatic sensor data collections and sensor data intra-communications so that rehabilitation data could be properly collected. Three WSN motes are deployed in this system. Two motes are used for a set of sanding hand blocks, and the remaining mote is used for the reciprocal exercise platform. The most important feature of our approach is that three motes can be easily attached to conventional sanding units with less wiring and setup efforts to fast realize -plus functions. In addition to the collections of kinematic performance, the accelerations, grip force, applied weight, and the angle of upper plank are also automatically collected. The collected data is further transformed as rehabilitation performance indices (RPI) to guide the users to maximize their achievements, as well as to provide rehabilitation records for diagnoses and assessments. Finally, a system prototype is produced in this project to validate our approaches.

Further analysis on matrix operation of AHP

This paper is major on discussing the paper of Barzilai, Cook and Golany published in Operations Research Letters to discuss consistent weights for judgment matrices of the relative importance of alternatives. We point out that they misuse the reciprocal operation to imply meaningless alternatives such that their challenge to conventional AHP is not well founded. Our findings should result in the development of both the theoretical and practical applications.

OPTIMIZATION OF RECIPROCALS AND SQUARE ROOTS ON THE i860 MICROPROCESSOR

Reciprocal and reciprocal square root operations are partially supported by the i860 floating point unit, whereas square roots are not. We point out the reasons for this, and its consequences for the optimization of code involving many reciprocal square roots, such as many-body simulations involving Coulomb-like potentials. We conclude that code which can be optimized to explicitly combine reciprocals and square roots in the form of reciprocal square roots can attain significantly higher performance, and that assembly language coding of such operations can make the greatest use of the hardware by calculating only to the accuracy required, which may be less than single precision.

True 3D Computer Modeling: Sculpture of Numerical Abstraction

True 3D Computer Modeling: Sculpture of Numerical Abstraction