The Contribution of United States Aircraft Reconnaissance Data to the China Meteorological Administration Tropical Cyclone Intensity Data:An Evaluation of Homogeneity

This paper investigates the homogeneity of United States aircraft reconnaissance data and the impact of these data on the homogeneity of the tropical cyclone(TC)best track data for the seasons 1949-1987 generated by the China Meteorological Administration(CMA).The evaluation of the reconnaissance data shows that the minimum central sea level pressure(MCP)data are relatively homogeneous,whereas the maximum sustained wind(MSW)data show both overestimations and spurious abrupt changes.Statistical comparisons suggest that both the reconnaissance MCP and MSW were well incorporated into the CMA TC best track dataset.Although no spurious abrupt changes were evident in the reconnaissance-related best track MCP data,two spurious changepoints were identified in the remainder of the best-track MCP data.Furthermore,the influence of the reconnaissance MSWs seems to extend to the best track MSWs unrelated to reconnaissance,which might reflect the optimistic confidence in making higher estimates due to the overestimated extreme wind“observations”.In addition,the overestimation of either the reconnaissance MSWs or the best track MSWs was greater during the early decades compared to later decades,which reflects the important influence of reconnaissance data on the CMA TC best track dataset.The wind-pressure relationship(WPR)used in the CMA TC best track dataset is also evaluated and is found to overestimate the MSW,which may lead to inhomogeneity within the dataset between the aircraft reconnaissance era and the satellite era.

Support vector regression-based operational effectiveness evaluation approach to reconnaissance satellite system

As one of the most important part of weapon system of systems(WSoS),quantitative evaluation of reconnaissance satellite system(RSS)is indispensable during its construction and application.Aiming at the problem of nonlinear effectiveness evaluation under small sample conditions,we propose an evaluation method based on support vector regression(SVR)to effectively address the defects of traditional methods.Considering the performance of SVR is influenced by the penalty factor,kernel type,and other parameters deeply,the improved grey wolf optimizer(IGWO)is employed for parameter optimization.In the proposed IGWO algorithm,the opposition-based learning strategy is adopted to increase the probability of avoiding the local optima,the mutation operator is used to escape from premature convergence and differential convergence factors are applied to increase the rate of convergence.Numerical experiments of 14 test functions validate the applicability of IGWO algorithm dealing with global optimization.The index system and evaluation method are constructed based on the characteristics of RSS.To validate the proposed IGWO-SVR evaluation method,eight benchmark data sets and combat simulation are employed to estimate the evaluation accuracy,convergence performance and computational complexity.According to the experimental results,the proposed method outperforms several prediction based evaluation methods,verifies the superiority and effectiveness in RSS operational effectiveness evaluation.

Analysis of detection capabilities of LEO reconnaissance satellite constellation based on coverage performance

In the design problem of low earth orbit(LEO) reconnaissance satellite constellation, optimization of coverage performance is the design goal in most current methods. However,in the using process, the user only concerns with the detection capabilities rather than coverage performance. To establish the relationship between these two aspects, the reconnaissance processes of normal stochastic targets are considered and the mathematic models of detection processes are built. The indicators of coverage performance are used to evaluate the detection probability and expectation of detection time delay, which are important factors in reconnaissance constellation estimation viewed from military intelligence discipline. The conclusions confirmed by the final simulation will be useful in LEO reconnaissance constellation design, optimization and evaluation.

Field reconnaissance of the 2007 Niigata-Chuetsu Oki earthquake

As part of the 2007 Tri-Center Field Mission to Japan, a reconnaissance team comprised of fourteen graduate students and three faculty members from three U.S. earthquake engineering research centers, namely, Multidisciplinary Center for Earthquake Engineering Research （MCEER）, Mid-America Earthquake Center （MAE）, and Pacific Earthquake Engineering Research Center （PEER）, undertook a reconnaissance visit to the affected area shortly after the 2007 Niigata- Chuetsu Oki earthquake. This mission provided an opportunity to review the nature of the earthquake damage that occurred, as well as to assess the significance of the damage from an educational perspective. This paper reports on the seismological characteristics of the earthquake, preliminary findings of geotechnical and structural damage, and the causes of the observed failures or collapses. In addition, economic and socio-economic considerations and experiences to enhance earthquake resilience are presented.

Re-examining Tropical Cyclone Fullness Using Aircraft Reconnaissance Data

We use FLIGHT+ aircraft reconnaissance data for tropical cyclones(TCs) in the North Atlantic and Eastern Pacific from 1997 to 2015 to re-examine TC fullness(TCF) characteristics at the flight level.The results show a strong positive correlation between the flight-level TCF and the intensity of TCs,with the flight-level TCF increasing much more rapidly than the near-surface TCF with increasing intensity of the TCs.The tangential wind in small-TCF hurricanes is statistically significantly stronger near the eye center than that in large-TCF hurricanes.Large-TCF hurricanes have a ring-like vorticity structure.No significant correlation is observed between the flight-level TCF and the comparative extent of the vorticityskirt region occupied in the outer core skirt.The proportion of the rapid filamentation zone in the outer core skirt increases with increasing flight-level TCF.The differences in entropy between the radius of the maximum wind and the outer boundary of the outer core skirt also increase with increasing flight-level TCF.

Projectile-Borne Video Reconnaissance System

Aiming at applications as a projectile-borne video reconnaissance system, the overall design and prototype in principle of a mortar video reconnaissance system bomb were developed. Mortar launched test results show that the initial integrated system was capable of transmitting images through tens of kilometers with the image resolution identifying effectively tactical targets such as roads, hills, caverns, trees and rivers. The projectile-borne video reconnaissance system is able to meet the needs of tactical target identification and battle damage assessment for tactical operations. The study will provide significant technological support for further independent development.

A multiple heterogeneous UAVs reconnaissance mission planning and re-planning algorithm

Reconnaissance mission planning of multiple unmanned aerial vehicles(UAVs)under an adversarial environment is a discrete combinatorial optimization problem which is proved to be a non-deterministic polynomial(NP)-complete problem.The purpose of this study is to research intelligent multiUAVs reconnaissance mission planning and online re-planning algorithm under various constraints in mission areas.For numerous targets scattered in the wide area,a reconnaissance mission planning and re-planning system is established,which includes five modules,including intelligence analysis,sub-mission area division,mission sequence planning,path smoothing,and online re-planning.The intelligence analysis module depicts the attribute of targets and the heterogeneous characteristic of UAVs and computes the number of sub-mission areas on consideration of voyage distance constraints.In the sub-mission area division module,an improved K-means clustering algorithm is designed to divide the reconnaissance mission area into several sub-mission areas,and each sub-mission is detected by the UAV loaded with various detective sensors.To control reconnaissance cost,the sampling and iteration algorithms are proposed in the mission sequence planning module,which are utilized to solve the optimal or approximately optimal reconnaissance sequence.In the path smoothing module,the Dubins curve is applied to smooth the flight path,which assure the availability of the planned path.Furthermore,an online re-planning algorithm is designed for the uncertain factor that the UAV is damaged.Finally,reconnaissance planning and re-planning experiment results show that the algorithm proposed in this paper are effective and the algorithms designed for sequence planning have a great advantage in solving efficiency and optimality.

Geographical Reconnaissance of Household in Northern Nigeria towards Optimizing Indoor Residual Spraying Method for Malaria Elimination

As a part of an effort to roll back malaria in Nigeria, exploring the use of geographically related tools triggered the use of modern approaches of knowing the spatial distribution of target populations to attain significant malaria elimination intervention. GIS tool was used for geographical reconnaissance (GR), providing demographic data on respondents’ household and spatial information on the distribution of households in the selected location. A cross-sectional study design was used to collect spatial data in the two locations, while a quantitative questionnaire was used to collect the household data. The analysis of field data indicated that 49,500 unique households were enumerated and thus included in the Indoor Residual Spraying to prevent malaria infection, covering 424 towns in the two Local Government Areas (LGAs). 383,301 persons were recorded during the GR exercise in Doma and Nassarawa Eggon LGAs out of which 79,339 were children of agesless than five years, with 13,526 pregnant women. Further data analysis revealed that the average number of persons per household in both LGAs was approximately eight. The spatial information from the GR provides a foundation for an updateable database for any future survey for developmental activities in Nigeria. The use of modern GR approach has proved to be accurate, reliable and more cost effective and less cumbersome than the traditional approach in the collection and geo-positioning of household data. Use of Garmin e-Trex GPS handheld instruments to collect household data in the designated areas removed the constraints of expensive Personal Digital Assistants and reduced errors of wrong location coordinates. Several African countries which did not use GR or applied the use of Geospatial tool appropriately had setbacks. The previous study in other countries showed limitations which was characterized by substantial inherent logistical and technical challenges culminating in missed targets. This setback was addressed in our study.

A framework of force of information influence and application for C4KISR system

The subversive nature of information war lies not only in the information itself, but also in the circulation and application of information. It has always been a challenge to quantitatively analyze the function and effect of information flow through command, control, communications, computer, kill, intelligence,surveillance, reconnaissance (C4KISR) system. In this work, we propose a framework of force of information influence and the methods for calculating the force of information influence between C4KISR nodes of sensing, intelligence processing,decision making and fire attack. Specifically, the basic concept of force of information influence between nodes in C4KISR system is formally proposed and its mathematical definition is provided. Then, based on the information entropy theory, the model of force of information influence between C4KISR system nodes is constructed. Finally, the simulation experiments have been performed under an air defense and attack scenario. The experimental results show that, with the proposed force of information influence framework, we can effectively evaluate the contribution of information circulation through different C4KISR system nodes to the corresponding tasks. Our framework of force of information influence can also serve as an effective tool for the design and dynamic reconfiguration of C4KISR system architecture.

Blind reconnaissance of the pseudo-random sequence in DS/SS signal with negative SNR

This paper introduces a new theory and algorithm that can be used in blind detection of the carrier wave signal and the pseudo-random sequence of the direct sequence spread spectrum （DS/SS） signal with negative SNR. First, without any a priori knowledge of the DS/SS signal, the carrier wave signal can be detected from DS/SS signal with negative SNR by using stochastic differential equations and energy detection method. Based on this, the pseudo-random sequence can also be blindly detected in DS/SS signal with negative SNR by reducing noise of the nonlinear signal and the algorithm of wavelet multiscale decomposition algorithm. Finally, the computer simulation shows that we can detect the carrier wave signal with SNR=-27 dB and the pseudo-random sequence under error code ratio 10^-4with SNR =-10 dB.

Design of a wide-field target detection and tracking system using the segmented planar imaging detector for electro-optical reconnaissance

Detecting and tracking multiple targets simultaneously for space-based surveillance requires multiple cameras,which leads to a large system volume and weight. To address this problem, we propose a wide-field detection and tracking system using the segmented planar imaging detector for electro-optical reconnaissance. This study realizes two operating modes by changing the working paired lenslets and corresponding waveguide arrays： a detection mode and a tracking mode. A model system was simulated and evaluated using the peak signal-to-noise ratio method. The simulation results indicate that the detection and tracking system can realize wide-field detection and narrow-field, multi-target, high-resolution tracking without moving parts.

Design and research of signal-level airborne electronic reconnaissance simulation system

Airborne passive electronic reconnaissance equipment has developed rapidly during recent years.However,because of its expensive and unavailable military features,the simulation realization of these equipment needs to be solved.And the smaller the simulation particle is,the better the simulation system will be.In this study,a signal-level airborne electronic reconnaissance simulation system was built.Mathematical model and simulation realization of each part are introduced in this study.Focusing on the shortness of traditional signal sorting methods,we creatively proposed a presorting method based on the Euclidean distance inside signal flows.Simulation results show that the presorting method based on Euclidean distance successfully reduced the pressure on main sorting and appeared good for signal sorting.Simulation test results of each model built in this study are also shown in the study.This study provides a new thought on the realization of airborne electronic reconnaissance equipment and benefits the development of electronic countermeasure.

Blind source separation algorithm for communication complex signals in communication reconnaissance

Most blind source separation algorithms are only applicable to real signals,while in communication reconnaissance processed signals are complex.To solve this problem,a blind source separation algorithm for communication complex signals is deduced,which is obtained by adopting the Kullback-Leibler divergence to measure the signals’independence.On the other hand,the performance of natural gradient is better than that of stochastic gradient,thus the natural gradient of the cost function is used to optimize the algorithm.According to the conclusion that the signal’s mixing matrix after whitening is orthogonal,we deduce the iterative algorithm by constraining the separating matrix to an orthogonal matrix.Simulation results show that this algorithm can efficiently separate the source signals even in noise circumstances.

Fusion of color and hallucinated depth features for enhanced multimodal deep learning-based damage segmentation

Recent advances in computer vision and deep learning have shown that the fusion of depth information can significantly enhance the performance of RGB-based damage detection and segmentation models.However,alongside the advantages,depth-sensing also presents many practical challenges.For instance,the depth sensors impose an additional payload burden on the robotic inspection platforms limiting the operation time and increasing the inspection cost.Additionally,some lidar-based depth sensors have poor outdoor performance due to sunlight contamination during the daytime.In this context,this study investigates the feasibility of abolishing depth-sensing at test time without compromising the segmentation performance.An autonomous damage segmentation framework is developed,based on recent advancements in vision-based multi-modal sensing such as modality hallucination(MH)and monocular depth estimation(MDE),which require depth data only during the model training.At the time of deployment,depth data becomes expendable as it can be simulated from the corresponding RGB frames.This makes it possible to reap the benefits of depth fusion without any depth perception per se.This study explored two different depth encoding techniques and three different fusion strategies in addition to a baseline RGB-based model.The proposed approach is validated on computer-generated RGB-D data of reinforced concrete buildings subjected to seismic damage.It was observed that the surrogate techniques can increase the segmentation IoU by up to 20.1%with a negligible increase in the computation cost.Overall,this study is believed to make a positive contribution to enhancing the resilience of critical civil infrastructure.

An executable modeling and analyzing approach to C4ISR architecture

To analyze the behavioral model of the command,control,communication,computer,intelligence,surveillance,reconnaissance(C4ISR)architecture,we propose an executable modeling and analyzing approach to it.First,the meta concept model of the C4ISR architecture is introduced.According to the meta concept model,we construct the executable meta models of the C4ISR architecture by extending the meta models of fUML.Then,we define the concrete syntax and executable activity algebra(EAA)semantics for executable models.The semantics functions are introduced to translating the syntax description of executable models into the item of EAA.To support the execution of models,we propose the executable rules which are the structural operational semantics of EAA.Finally,an area air defense of the C4ISR system is used to illustrate the feasibility of the approach.

System of developing scale modeling and simulation for URAV

The unmanned reconnaissance aerial vehicle （URAV） plays an important role in battlefield monitoring and information acquiring because of its advantage of zero casualties, and has thus attracted considerable attention of the world. The URAV was developed rapidly in our country, however, no scientific assessment methods have yet been provided owing to different fight requirements of armed forces. Considering the demand of the missile artillery on the martial information, the model of information requirement of combat force, the reconnaissance ability of URAV, the survivability of URAV, and the task reliability of URAV were constructed, respectively. By synthesizing the mathematic models above, the model of developing demand was constructed on the URAV equipment. It simulated and calculated some URAV equipment developing scales, and explored a way of settling the problem of URAV equipment developing demand.

Blind carrier frequency estimation for phase shift keying signals in low signal to noise ratio

In order to solve the problem of carrier frequency blind estimation of PSK signals in electronic reconnaissance, a new estimation method was proposed. The phase shift keying（PSK） signal was divided into several overlapping intervals which had equal length, and the spectrum concentration measures of every interval were extracted by the FFT. And then, using the grid-density clustering, the spectrum concentration measures were classified into two categories, the narrowband spectrum interval and the wideband spectrum interval. The narrowband spectrum interval was regarded as the characteristic class. The spectrums of the characteristic class were accumulated to estimate the carrier frequency of PSK signal. The proposed method had avoided the non linear operation in the traditional PSK signal carrier frequency estimation algorithm. Thus, the signal to noise ratio （SNR） threshold was remarkably decreased. Moreover, the proposed method did not need the prior knowledge of the signal, which was suitable to the electronic reconnaissance occasion. Experimental results had verified the validity of the proposed estimation method in low SNR.

Rapid building damage assessment system using mobile phone technology

One common scenario during disasters such as earthquakes is that the activity of damage field reconnaissance on site is not well-coordinated. For example in Italy the damage assessment of structures after an earthquake is managed from the Italian Emergency Authority, using printed forms （AeDES） which are filled by experts on site generating a lot of confusion in filling and transferring the forms to the Disaster Management Operative Center. Because of this, the paper explores the viability of using mobile communication technologies （smart phones） and the Web to develop response systems that would aid communities after a major disaster, providing channels for allowing residents and responders ofuploading and distributing information, related to structural damages coordinating the damage field reconnaissance. A mobile application that can be run by residents on smart phones has been developed, to give an initial damage evaluation of the area, which is going to be very useful when resources （e.g. the number of experts is limited）. The mobile application has been tested for the first time during 2012 Emilia earthquake to enhance the emergency response, showing the efficiency of the proposed method in statistical terms comparing the proposed procedure with the standard procedure.

Seismic damage to road networks subjected to earthquakes in Nepal,2015

The Gorkha earthquake in Nepal led to many landslides and severe damage to the transportation infrastructure. After careful comparison of the aerial photographs and satellite images before and after the earthquake, partially verified by a field study, more than 2,064 landslides and many road failures were observed. Many bridges, especially steel-truss and suspension bridges, suffered little damage from inertia loads during the earthquake, but were severely damaged due to rockfalls. Potential geological hazards hindered the delivery of supplies in mountainous areas, and road closures impeded the overall speed of rehabilitation.

Seismic performance of buildings during 2011 Van earthquakes and rebuilding efforts

The October 23, 2011 M7.2 Tabanli - Van and November 9, 2011 M5.2 Edremit - Van earthquakes caused damage in a widespread area across the Van province in Turkey. The ground motions, the damage caused by these earthquakes and the recent progress related to recovery efforts are presented herein. First, the key properties of the recorded strong ground motions like spectral amplitudes and directionality are evaluated. The observed damage in the affected reinforced concrete and masonry structures are discussed. The set of common structural damage mechanisms （i.e., soft story failure, torsional response due to plan irregularity, short column failure, pull out failure, pounding） observed in the damaged buildings were identified. The relationship between the key structural properties and the extent of damage is investigated. The primary loss drivers across the region were identified to be the poor quality of workmanship and improper use of building materials. The results from the investigation suggest that a large portion of the loss could have been prevented if sufficient attention and care were given to the implementation of the design regulations and in particular to the construction practice. Lastly, the recent progress in the ongoing rebuildin~ activities is presented.