Optimal Launch Research Articles

PAPR-Degraded Secure OFDM-WDM-PON Based on Chaotic Set-Partitioned SLM

This letter proposes and experimentally demonstrates an orthogonal frequency division multiplexing wavelength division multiplexing passive optical network (OFDM-WDM-PON) system based on novel chaotic set-partitioned selective mapping (SP-SLM) scheme. With the implementation of a three-dimensional chaotic system, peak-to-average power ratio (PAPR) reduction and chaotic encryption are simultaneously realized on the process of OFDM signal modulation, so as to enhance the system performance in the presence of PAPR, bit error rate (BER), fiber nonlinear tolerance and security. The experimental results show that, when compared with original OFDM signal, the OFDM signal with SP-SLM can achieve 4 dB PAPR reduction at the complementary cumulative distribution function value of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10^{-4}$ </tex-math></inline-formula> , as well as a 1.1 dB gain in receiver sensitivity at a BER of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10^{-3}$ </tex-math></inline-formula> . For fiber nonlinear tolerance, the optimal launch fiber power of OFDM signal with SP-SLM is 10 dBm, which is better than 9 dBm of original OFDM signal under the same received optical power of −16 dBm. Furthermore, the key space of the proposed scheme can reach up to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10^{98}$ </tex-math></inline-formula> , which is large enough to effectively protect against illegal attackers.

Coupling efficiency of a laser diode to a single-mode fiber via a microlens on the fiber tip

A conical microlens on the tip of a fiber for improving the coupling efficiency (CE) of a laser diode and a single-mode fiber in butterfly packaging was experimentally fabricated via the grinding and polishing method and theoretically designed using the beam propagation method. The CE, varying with working distance, was explored under all kinds of optical coupling system parameters, such as incident wavelength, laser beam waist radius, numerical aperture of the fiber, refractive index, and diameter of the microlens. The optimal working distance for the maximal CE was located at approximately 15 μm, proving that the conical-tip coupling was a tight packaging type. Therefore, the CE trends under misalignment and tolerance adjustments could be explained by the spherical aberration theory and light-gathering ability of the microlens. The results are useful in optimum launch optics for designing and fabricating microlens tips on coupled packaging of optoelectronic devices.

Optimization of Ecologically Safe Water Management in Reclamation Systems Under Water Resources Shortage

The optimized designed irrigation scheme and water distribution system to reduce the anthropogenic impact and remove the pollutants by 20–25 % have been presented. The optimal launch sequencing of the irrigation equipment has been introduced by using the study irrigation area under conditions of water resources scarcity to determine the launch sequences regardless the crop rotation used. The presented model allows to bring down the irrigation water consumption by 30 % while decreasing the working cycle of the irrigation material, specifically by reducing the number of land irrigations without any impact on the yield.

РОЗРАХУНОК ЗОНИ УРАЖЕННЯ ЗЕНІТНОГО РАКЕТНОГО КОМПЛЕКСУ ЗА ДОПОМОГОЮ АЛГОРИТМУ БАГАТОКРИТЕРІАЛЬНОЇ ОПТИМІЗАЦІЇ

The kill zone is the main characteristic of the surface-to-air missile system, which characterizes, firstly, the combat capabilities of the system to hit targets of various types, and secondly, the energy capabilities of surface-to-air missiles to achieve targets, taking into account detailed calculation of the shape of the kill zone of the surface-to-air missile system is a time-consuming process, which without proper automation leads to unjustified time to perform. This article proposes a method of using a genetic algorithm with multicriteria optimization to automate the calculation of the kill zone of the surface-to-air missile system. The essence of the proposed technique is to find a set of pareto-optimal trajectories of a surface-to-air missile, the endpoints of which are the limit in terms of the ability to reach the aerial target with the necessary motion parameters and taking into account the range of target detection by fire-control radar of surface-to-air missile system. That is, one of the coordinates (the altitude or distance) of the boundary point can not be improved without the reducing of the other coordinate (the principle of pareto-optimality). This approach allows in the early stages of design to evaluate the kill zone of the surface-to-air missile system, being at design, and promptly implement effective technical solutions to increase its tactical and technical characteristics. Additional results of the calculation of the kill zone of the surface-to-air missile system according to the proposed method are data on the optimal launch angles of the surface-to-air missile, which can be taken into account when designing the launcher of the system, as well as data highlighting some features of surface-to-air missile flight.

Prediction of Mobile Model Price us ing Machine Learning Techniques

Mobile phone has become a common commodity and usually the most common purchased item. Thousands of types of mobiles are released every year with new features and new specification and new designs. So the real question is prediction is that what is the real price of the mobile and to estimate the price of the mobile within the market for optimal marketing and successful launch of the product. Price has become a major factor for development of any product and its sustainability in the market. Mobile prices also impact the marketing of the mobile and also its popularity with other competitors. With the available specifications and desired designs, money is also an important factor to survive within the market. Customer usually sees that they are able to buy with the specification with the given estimated price or not. So to estimating the price is an important factor before releasing the mobile and also to know about the market and competitors. In this Prediction, Dataset is collected from the existing market and different algorithms are applied to reduce the complexity and also identify the major selection features and get the best comparison within the data .This Tool is used to find the best price with maximum specifications.

Особенности проектирования траекторий перспективных космических аппаратов для исследования Венеры

The paper describes the mission profile of the perspective Venus exploration project spacecraft with launches planned for 2027−2031. The main aspects of selecting the optimal launch dates are considered. The sequences of an orbiter injection to a highly elliptical orbit and a lander delivery to the surface of Venus are described. The rationale for the operating orbit as well as for the injection sequence that will enable Venus-to-Earth data transfer are provided. The lifespan of the lander, including its parachute descent, is limited by the high temperature of the lower atmosphere close to the surface (up to 460 degrees Celsius) and is expected to be no more than three hours. Therefore, a key feature of the mission profile development is designing the sequence of the orbital vehicle maneuvers, which ensures robust communication with the lander during this time within a range of 40 thousand kilometers.

Effect of misalignment on coupling efficiency in laser diode to single-mode circular core graded-index fiber coupling via cylindrical microlens on the fiber tip

Abstract We report here the first theoretical prediction of coupling efficiency of the laser diode to single-mode graded-index fiber coupling via cylindrical microlens on the tip of the fiber in presence of possible transverse and angular mismatches. Moderately efficient cylindrical microlens on the fiber is easily fabricable and graded-index fiber has less sensitivity to macro as well as micro bending. Thus this coupling device emerges as a potential candidate in the field of coupling optics. The analysis takes into consideration the allowable aperture provided by cylindrical microlens. Further, we shall consider here the coupling in the vertical plane only since the coupling in the horizontal plane has poor performance. Using the relevant ABCD matrix of refraction for a cylindrical lens in the vertical plane, we prescribe analytical expressions of the coupling efficiencies in presence of said kinds of misalignments. In our analysis, we use Gaussian field distribution for both the laser and fiber fields. We carry on our investigation for two commonly used wavelengths namely 1.3 and 1.5 µm. As an example of graded-index fiber, we use some typical step, parabolic, and triangular index fibers in our study. The execution of the prescribed formulations involves little computation. Thus the evaluation of the concerned coupling efficiencies is very much user friendly. The present analysis surfaces the tolerance factors of the coupling devices. Accordingly, the results will prove beneficial to designers and packagers in respect of the design of such coupler involving cylindrical microlens in the field of optimum launch optics.

Managing the Versioning Decision over an App’s Lifetime

The authors investigate app publishers’ decisions to offer free, paid, or both versions of an app over an app’s lifetime by taking into account the interplays between the demand for the free and paid versions and publishers’ consideration of future profit streams. Their empirical analyses are based on a comprehensive model of publishers’ versioning decisions calibrated on a data set of 584 top-downloaded apps on Google Play. They find contemporaneous cannibalization but positive intertemporal cross-effects on new users’ demand between the two versions. In addition, the free version’s active user base and in-app purchase and advertising revenues are reduced by the presence of a paid version, but not vice versa. Among the three options, offering the paid version first is the most common optimal launch strategy and applies to 40% of apps in the data. The evolutionary patterns of optimal versioning decisions vary by app category and are related to apps’ abilities to monetize different revenue sources. This study provides insights on how to strategically manage the versioning decision over an app’s lifetime and shows how publishers can make their free version apps more profitable via the deployment or elimination of the paid version.

A medicine adoption model for assessing the expected effects of additional real-world evidence (RWE) at product launch

Introduction The optimal launch and adoption of novel medicines require effective navigation of the commercial and regulatory landscape, including three key gatekeeper groups: regulators, payors, and prescribers. Traditionally, despite lacking generalisability, the pharmaceutical industry provides Phase III randomized controlled trial evidence to gatekeepers. Despite additional real-world evidence (RWE) improving the generalisability of evidence, the provision of RWE remains in its infancy. The industry may use a multiple stakeholder approach to RWE generation to address each group's priorities and expectations effectively. Methods The Jandhyala Method observed a consensus of expert opinion on the expected effects of supplementing randomised controlled trial evidence (RCTE) with RWE on the depth and time to maximal adoption. The study recruited participants from two of the three gatekeeper stakeholder groups (prescribers and payors) and their four aligned industry stakeholder groups (market access, commercial, medical affairs, and regulatory affairs) groups involved in the approval or adoption of investigational medicines. Results The observed consensus predicted a shortened time to maximal adoption by 22% and increased maximal adoption by 31% of a new medicine with additional RWE at launch. The suggested rationales for these effects varied across stakeholder groups and between specific effects. The results found the prescriber gatekeeper to be dominant in driving the predicted shortening of adoption. No such dominant subsystem was identified for the expected increase in adoption depth, although a potential rationale was the broader population observed in the supplementary RWE. Conclusions The proposed model provides an intuitive temporal framework within which subsystem logic can be further researched to identify and address stakeholder groups’ needs and weigh those needs. Preliminary results appear to support adopting a multiple stakeholder approach to RWE for augmenting the uptake of novel medicines.

Uncertainty quantification for multidisciplinary launch vehicle design using model order reduction and spectral methods

The early design phase of launch vehicles often involves low fidelity models that are characterized by a high level of modeling uncertainties. These uncertainties have to be propagated into the whole design process in order to ensure the robustness of the found vehicle architecture. Launch vehicle design involves trajectory optimization that induces a large computational cost for the uncertainty propagation phase using nested loop approach (outer uncertainty loop and inner optimal control loop). In this paper, a methodology is proposed in order to build a surrogate model of the uncertainty propagation phase on the trajectory optimization in order to carry out the uncertainty quantification at a reduced cost. The proposed approach couples reduced order model and spectral methods in order to allow to generate optimal launch vehicle trajectories as functions of the input uncertainties. The method is applied to two-stage-to-orbit launch vehicle design in several uncertainty quantification analyses (reliability analysis, sensitivity analysis, quantile estimation).

Interception probability simulation and analysis of salvo of two electromagnetic coil launched anti-torpedo torpedoes

Electromagnetic coil launch is an important branch of electromagnetic launch (EML) technology, which is suitable for launching anti-torpedo torpedo (ATT). This paper focuses on the EML parameters and the interception probability of the EML two ATTs salvo. Based on the launching model of a multi-stage coil launcher, the trajectory model of the ATT and the attacking torpedo, a calculation method for the EML two ATTs salvo parameters is proposed, with the conditions of capture and interception given reasonably. An adaptive particle swarm optimization (APSO) algorithm is proposed to calculate the optimal launching parameters, by designing the adaptive inertia weight and time-varying study factors. According to the analysis of the simulation with Monte Carlo method, EML will improve the interception probability effectively, and the interception probability is affected by the launching range. The results demonstrate good performance of the proposed APSO in calculating EML parameters for the two ATTs salvo in certain combat situation. Implications of these results are particular regarding the command and decision in the anti-torpedo combat.

Nonlinearity compensation and link margin analysis of 112-Gbps circular-polarization division multiplexed fiber optic communication system using a digital coherent receiver over 800-km SSMF link

Nonlinear effects have been considered as the major limitations in coherent optical (CO) fiber transmission system. Digital signal processing (DSP)-based CO receiver with digital backpropagation (DBP) method has recently facilitated the compensation of fiber nonlinear impairments as well as compensating dispersion of optical fiber. In this paper, for the first time, a comprehensive design is presented for a newly introduced DSP-based CO receiver with the 8-quadrature amplitude modulation (8-QAM) circular-polarization division multiplexed (CPDM) fiber optic communication (FOC) system to investigate the impact of nonlinearities. We have examined the performance of nonlinearity compensating DSP-based CO receiver with DBP method and demonstrated that it can be effectively employed to mitigate the intrachannel nonlinearities in CPDM 8-QAM FOC system over 800-km SSMF link. Accordingly, by effectively compensating the fiber nonlinearities, we have analyzed the performance of bit error rate, optical signal-to-noise ratio (OSNR), optimum launch power, and investigate the link margin by evaluating OSNR margin for a specific launch power. Moreover, a CPDM technique helps as a very suitable means of maximizing the link capacity as well as enhancing the spectral efficiency of the FOC system.

Analog-digital hybrid chaos-based long-haul coherent optical secure communication.

We propose and numerically investigate a chaotic optical coherent secure communication scheme, which supports long-haul secure transmission for signals in advanced modulation formats. A hybrid optical chaos system is designed with coordination of digital and analog signals. The hybrid entropy source provides a broadband analog optical chaos signal, which could serve as the carrier to load quadrature amplitude modulation (QAM) data. Simultaneously, a digital binary signal generated from the entropy source is transmitted to establish long-haul chaotic synchronization. Coherent detection is utilized at the receiver, and a digital signal processing (DSP) algorithm is adopted to reduce transmission distortion. A 5 Gbaud 16QAM signal is encrypted by a phase chaos carrier with the effective bandwidth of 5.8 GHz. A bit error rate (BER) below forward error correction (FEC) can be achieved after transmitting over 1600 km based on digital-signal-induced chaos synchronization technology. Optimal launch power is investigated to minimize nonlinear effects of transmission links. System security is guaranteed by the high dynamical complexity of the chaotic source and the sensitive time delay as the secret key.

Independent and mixed transmission of 166.5 Gb/s PM‐8QAM and 222 Gb/s PM‐16QAM Nyquist‐wavelength division multiplexed superchannel for long‐haul metro network

SummaryThis paper investigates the Nyquist‐wavelength division multiplexed (Nyquist‐WDM) terabit superchannel by employing independent and mixed line rate (MLR) transmission of different polarization‐multiplexed quadrature amplitude modulation (PM‐QAM) subcarriers. Here, terabit superchannel transmission including forward error correction overhead is successfully achieved by employing either 7 × 166.5 Gb/s PM‐8QAM or 5 × 222 Gb/s PM‐16QAM or both 2 × 166.5 Gb/s PM‐8QAM and 3 × 222 Gb/s PM‐16QAM simultaneous transmission. Considering linear filtering penalties and nonlinear propagation effects, the proposed superchannel is transmitted over standard single‐mode fiber (SSMF) and pure silica core fiber (PSCF) along with erbium‐doped fiber amplifier (EDFA) at 19.8‐ and 15.12‐dB span loss for SSMF and PSCF, respectively. The performance of both terabit superchannels is analyzed in terms of maximum reach, good spectral efficiency, highest transmission capacity, and optimum launch power with variation in channel spacing from 50‐GHz fixed ITU‐T grid to 29 GHz, at an acceptable bit error rate (BER). To achieve BER 4 × 10−3, MLR‐based 166.5 Gb/s PM‐8QAM and 222 Gb/s PM‐16QAM suffer a penalty of 5.5‐ and 9.2‐dB OSNR over Nyquist‐only 7 × 166.5 Gb/s PM‐8QAM and 5 × 222 Gb/s PM‐16QAM transmission at the advent of a flexible multi‐flow transponder. It is observed that at 33.33‐GHz Nyquist spacing over PSCF, 5 × 222 Gb/s PM‐16QAM and 7 × 166.5 Gb/s PM‐8QAM superchannels deliver a reach up to 1800 and 2970 km, while MLR approach results in extreme reach of 2250 and 3600 km over PSCF as per MLR PM‐16QAM and PM‐8QAM subcarriers, respectively. Hence, an appreciable spectral efficiency–distance product (SEDP) is achieved due to PSCF at Nyquist spacing of 33.33 GHz with 5.25 bit/s/Hz spectral efficiency. A good link power budget is also calculated for the proposed MLR‐based Nyquist‐WDM superchannel. MLR‐based PM‐16QAM and PM‐8QAM subcarriers deliver excellent SEDP of 11,812 and 18,900 bit/s/Hz·km, respectively, which is, to the best of author's knowledge, better on comparing with the other existing literature for single‐core channel explorations.

Huffman-Coded Sphere Shaping for Extended-Reach Single-Span Links

Huffman-coded sphere shaping (HCSS) is an algorithm for finite-length probabilistic constellation shaping, which provides nearly optimal energy efficiency at low implementation complexity. In this paper, we experimentally study the nonlinear performance of HCSS employing dual-polarization 64-ary quadrature amplitude modulation (DP-64QAM) in an extended-reach single-span link comprising 200 km of standard single-mode fiber (SSMF). We investigate the effects of shaping sequence length, dimensionality of symbol mapping, and shaping rate. We determine that the naive approach of Maxwell–Boltzmann distribution matching — which is optimal in the additive white Gaussian noise channel — provides a maximum achievable information rate (AIR) gain of 0.18 bits/4D-symbol with respect to uniform signaling at optimum launch power in the infinite length regime. Conversely, HCSS can achieve a gain of 0.37 bits/4D-symbol over uniform signaling using amplitude sequence length of 32, which may be implemented without multiplications, using integer comparison and addition operations only. Coded system performance, with a net data rate of approximately 425 Gb/s for both shaped and uniform inputs, is also analyzed.

Spectral-dependent electronic-photonic modeling of high-speed VCSEL-MMF links for optimized launch conditions.

We present spectral-dependent electronic-photonic modeling of vertical-cavity surface-emitting laser (VCSEL)-multimode fiber (MMF) links for next-generation high-speed interconnects. The beam coupling processes, between the VCSEL and the MMF and between the MMF and the photodetector (PD), are discussed, with spectral-dependent three-dimensional launch conditions analyzed. The model accounts for fiber effects on the transmission performance, specifically modal attenuation, dispersion, mode mixing, and mode partition noise. An advanced split-step small-segment (4-S) method simulates the signal evolution over the MMF with high accuracy and high efficiency. Experimental validation at 25 Gbps confirms the high accuracy of the VCSEL-MMF link model. The model reveals that larger radial offsets can further excite lower-order mode groups reducing the power distributed to higher-order groups when a tilted beam couples to the input fiber facet. With an optimized misalignment launch, the modal bandwidth is greatly improved by 3.8-fold compared to the conventional center launch. The model helps determine the optimum launch condition to improve link performance metrics such as transmission reach.

High Capacity Transmission in a Coupled-Core Three-Core Multi-Core Fiber

High-capacity, long-haul transmission over a coupled-core three-core multi-core fiber is investigated in a recirculating loop experiment. We report key system characteristics, such as the optimum launch power as well as the wavelength dependence and distance-evolution of mode-dependent loss and the impulse response time spread. We further performed two high data-rate, long-haul transmission demonstrations with more than 75 nm optical bandwidth in C- and L-bands over distances up to 4800 km. The reported data-rate of 172 Tb/s over 2040 km is the highest demonstrated in any multi-span transmission system employing optical fibers with standard cladding diameter of 125 micro-meter to date. Additionally, transmission of 81 Tb/s over 4800 km distance demonstrates the potential of using coupled-core multi-core fibers in combination with wideband optical signals over long-haul distances.

Supercritical carbon dioxide as a new working medium for pneumatic launch: A theoretical study

Compared with the conventionally gaseous or liquid working media, the specific internal energy of supercritical carbon dioxide (SCD) is higher at the same temperature and pressure, and the critical temperature of carbon dioxide is close to room temperature, making SCD a potential new working medium for pneumatic launch. To analyze the feasibility of this conception, an analytical model of a pneumatic catapult is established on basis of the conservations of mass and energy. The model consists of a high-pressure chamber and a low-pressure chamber connected by multiple valves, and there is a movable piston in the low-pressure chamber that can push an aircraft to accelerate. The effects of the launch readiness state of SCD in the high-pressure chamber, the initial volume of the low-pressure chamber and the valve control on the movement of the aircraft are analyzed. It is found that there is a restrictive relation between the temperature and pressure of the launch readiness state of SCD, i.e., there is a maximum allowable launch readiness pressure when the launch readiness temperature is fixed. If this restrictive relation is not satisfied, the working medium in the low-pressure chamber will drop to its triple point within a few milliseconds, leading to a launch failure. Owing to this restrictive relation, there is an optimal launch readiness state of SCD with the highest working capacity for any allowable launch readiness temperature. The pressure of the low-pressure chamber will decrease significantly as the initial volume increases, leading to a decreased acceleration of the aircraft. The acceleration can be controlled below a critical value by a designed sequential blasting technique of multiple valves. The calculated results show that a 500 kg aircraft can be accelerated from 0 to 58 m/s in 0.9 s with 36 kg of carbon dioxide. This research provides a new technique for the controllable cold launch of an aircraft.

Cooperative online Guide-Launch-Guide policy in a target-missile-defender engagement using deep reinforcement learning

A target-missile-defender engagement is considered, in which the missile attempts to intercept the target and the defender tries to prevent this interception via missile's interception. In this engagement, finding an optimal launch time of the defender and an optimal target guidance law before and after launch, which can be formulated as a switched system optimization problem, is crucial for improving performance of the target-defender team. The objective of this paper is to examine the potential of using deep reinforcement learning in switched system optimization. To that end, we propose estimating the optimal launch time of the defender and the optimal guidance law of the target online, using a reinforcement learning based method. A policy suggesting at each decision time the bang-bang target maneuver and whether or not to launch the defender was obtained and analyzed via simulations. Simulations showed the ability of the reinforcement learning based method to obtain a close to optimal level of performance in terms of the suggested cost function.

Effect of splice offset on optimum single mode fiber launch optics based on the proposed broadband laser diode in the context of DWDM

We investigate the tolerance potentiality of the prescribed wavelength dependent spot size relations of the recently proposed broadband semiconducting laser diode to withstand transverse misalignment effects in single mode fiber optimal launch optics. We simulate coupling between such a proposed source and the hyperbolic microlens fused fiber by taking lateral offset into consideration. We check the uniformity of coupling efficiency in the context of DWDM and show extreme elegance of our prescription of spot size relations in tolerating lateral offset to recommend the fabrication of such a source.