Search

In late March and early April 1965, as the North Vietnamese air defenses were attempting to blunt the impact of the Rolling Thunder bombing missions, they began to deploy a [...]

The increasing role of unmanned aerial vehicle (UAV) swarms in modern warfare poses a significant challenge to ground and air defense systems. Considering complex terrain environments and multi-sensor resources including radar and photoelectric systems constraints, a novel multi-sensor dynamic scheduling algorithm is proposed in this paper. Firstly, a transmission model with Fresnel zone under complex terrain and sensor models for radar/photoelectric systems are established. Considering the constraints of 6 factors, such as pitch angle, array scanning angle and threat levels, a detection model is developed subsequently. Secondly, to meet the real-time requirements of ground and air defense systems, a fast calculation method for Fresnel zone clearance using adaptive buffer is achieved. Thirdly, an improved Hungarian algorithm is proposed to solve the combinatorial optimization problem of sensor scheduling. Finally, simulation experiments are conducted to evaluate the algorithm performance under different conditions. The results demonstrate that the proposed approach significantly reduces the sensor switching rate while achieving a high sensor-UAV matching rate and high-threat matching rate. Furthermore, the simulation results verify the effectiveness of the proposed algorithm when applied to multi-sensor scheduling for defending UAV swarms. • Modern militaries need advanced sensor scheduling solutions to defend UAV. • Considering the Fresnel zone under complex terrain is crucial. • Adaptive buffer enables rapid calculation of Fresnel zone clearance. • Multiple sensor constraints make scheduling problems realistic. • Improved algorithm effectively enhances matching rates while reducing switching. [ABSTRACT FROM AUTHOR]

Copyright of Systems Engineering & Electronics is the property of Journal of Systems Engineering & Electronics Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This article focuses on air defense in maritime environment, which involves protecting friendly naval assets from aerial threats. Specifically, we define and address the Naval Air Defense Planning (NADP) problem, which consists of maneuvering decisions of the ships and scheduling weapons and sensors to the threats in order to maximize the total expected survival probability of friendly units. The NADP problem is more realistic and applicable than previous studies, as it considers features such as sensor assignment requirements, weapon and sensor blind sectors, sequence‐dependent setup times, and ship's infrared/radar signature. In this study, a mixed‐integer nonlinear programming model of the NADP problem is presented and heuristic solution approaches are developed. Computational results demonstrate that these heuristic approaches are both fast and efficient in solving the NADP problem. [ABSTRACT FROM AUTHOR]

To solve the problem of target damage assessment when fragments attack target under uncertain projectile and target intersection in an air defense intercept, this paper proposes a method for calculating target damage probability leveraging spatio-temporal finite multilayer fragments distribution and the target damage assessment algorithm based on cloud model theory. Drawing on the spatial dispersion characteristics of fragments of projectile proximity explosion, we divide into a finite number of fragments distribution planes based on the time series in space, set up a fragment layer dispersion model grounded in the time series and intersection criterion for determining the effective penetration of each layer of fragments into the target. Building on the precondition that the multilayer fragments of the time series effectively assail the target, we also establish the damage criterion of the perforation and penetration damage and deduce the damage probability calculation model. Taking the damage probability of the fragment layer in the spatio-temporal sequence to the target as the input state variable, we introduce cloud model theory to research the target damage assessment method. Combining the equivalent simulation experiment, the scientific and rational nature of the proposed method were validated through quantitative calculations and comparative analysis. [ABSTRACT FROM AUTHOR]

Scientific and reasonable satisfaction evaluation is an excellent way to understand the effects of building (structure) renovation and public satisfaction. This study presents a satisfaction evaluation of civil air defense engineering renovated into cooling place from the perspective of public experience. First, a satisfaction evaluation indicator system was constructed for civil air defense engineering renovated into cooling place from the perspective of public experience, focusing on 5 first-level indicators—location condition, spatial status, physical environment, service management, and emotional experience—and 27 second-level indicators. Second, the matter-element extension and combined weighting method were introduced to establish a satisfaction evaluation model for civil air defense engineering renovated into cooling place from the perspective of public experience. Finally, the rationality of the index system and feasibility of the evaluation model were verified by considering civil air defense cooling centers as examples. This research can provide a basis for the further optimization of such projects and the development and management of cities, as well as new ideas or methods for the satisfaction evaluation of similar old buildings (structures) after renovation. [ABSTRACT FROM AUTHOR]

The diffusion of small uncrewed aerial systems, mobile air defense systems, and one-way attack drones is rapidly changing the character of war, with US adversaries gaining new ways to contest the air domain. The traditional notion that air superiority is won or lost in the “blue skies”—the medium and higher altitudes where fighters and bombers typically operate—is outmoded. Even if an air force manages to gain blue-skies air superiority, the airspace below these altitudes—called the air littoral—remains contested. Absent a significant revision in US Air Force thinking and operations, the service risks ceding control of the air littoral to the adversary as well as other services. Instead, the US Air Force should drive a reinvention of airpower concepts, including that of air superiority, as well as the close air mission, to fulfill its purpose and role as experts of the air domain. [ABSTRACT FROM AUTHOR]

To effectively contest the air littoral, the US Air Force will need to meet two requirements: production at scale and continuous innovation. First, operating in this subdomain against a major power adversary will require an incredible mass of small drones, loitering munitions, and counter-unmanned aerial systems that exceeds the limits of the US defense industrial base and commercial market. Second, rapid innovation beyond the current Department of Defense procurement model is needed. This article describes these challenges and their implications for Air Force operations. It recommends the development of a new paradigm with three lines of effort: a new business model focused on capabilities, not programs; investment in scaling cutting-edge technologies; and a workforce that continuously upgrades the subdomain’s systems and software. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Ordnance Equipment Engineering is the property of Chongqing University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Ordnance Equipment Engineering is the property of Chongqing University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Reinforced concrete (RC) walls are extensively used in civil air defense engineering and are susceptible to low-speed impacts with high energy and massive weight during service. Therefore, it is crucial to consider the impact resistance of these walls and explore effective protection methods. The honeycomb structure, known for its energy-absorbing properties, has been widely utilized in aerospace, automotive, and maritime industries. However, there is a need for more research on applying honeycomb structures in energy-absorbing protection devices in civil engineering. This study proposes the use of honeycomb sandwich panels to protect civil air defense RC walls, creating a Honeycomb Sandwich Panel Composite RC wall (HSP-RC wall). Through pendulum impact experiments, we investigated the dynamic response of RC walls, both standard and HSP-RC walls with varying honeycomb parameters, under high-energy impacts. The goal was to evaluate the impact resistance of these RC walls, analyze the deformation differences among different HSP-RC walls, and examine the influence of honeycomb parameters on the impact protection effectiveness. The research results indicate that honeycomb sandwich panels can provide impact protection for RC walls by absorbing energy, and their protection effect is related to the parameters of the honeycomb core layer. This research result can be applied to RC structures that bear impact loads, achieving effective protection for RC structures. [ABSTRACT FROM AUTHOR]

In the offensive operations of the red and blue sides, in order to fully seize the battlefield air superiority, the blue side air defense fire units are usually taken as the first key targets. Therefore, it is of great significance to accurately predict the activity law of the blue side air defense fire units and scientifically design the joint reconnaissance and attack actions. Firstly, the maneuver support mode adopted by the air defense fire unit is systematically analyzed, the defense capability calculation formula is given based on the definition of defense capability, and the grid network model is introduced to complete the quantitative calculation. Based on the support scope constraint, position resource constraint and maneuver process constraint, the shortest maneuver route and the highest defense capability are taken as the optimization objectives for the actual support requirements. A prediction model for maneuvering route of ground air defense fire units is established. Secondly, aiming at the problem of solving the nonlinear model, the model linearization transformation and solving method are proposed. Then, on the basis of the optimal transfer route, an algorithm for constructing maneuver route library is designed to generate the probabilistic prediction scheme of blue side maneuver route and analyze the maneuver law of blue side air defense fire units. Finally, based on the case simulation, the feasibility and global efficiency of the designed model and method are verified, which can effectively predict the maneuvering route of blue side anti-aircraft fire units. [ABSTRACT FROM AUTHOR]

Aiming at the problem of poor attitude control quality caused by strong target maneuverability of air defense missile, an event-triggered control method is proposed. Firstly, the unknown command change rate caused by the strong maneuverability of the target and the reason of the large steady-state error caused by the excessive command change rate are analyzed. To solve this problem, a nonlinear fastest tracking differentiator is introduced to obtain the command change rate, the relationship between the command change rate and the attitude angle error is studied, the steady-state effect index is defined, and the new event-based control quantity is designed based on this index. By using sliding mode control and disturbance observer, the steady-state error of the system is suppressed within 5% error band under the condition of higher command change rate. In the background of engineering practice, the numerical simulation takes into account the deviation of aerodynamic parameters and the limiting of actuator, and the simulation results verify the effectiveness of the designed control system. [ABSTRACT FROM AUTHOR]

The US Indo-Pacific Command (USINDOPACOM) is tasked with deterring and preparing for a potential conflict with China, while also facing a clear threat from North Korea (DPRK) against the American Pacific homeland. To address mounting cooperation among adversaries, the US should establish a designated homeland defense operation, enabling USINDOPACOM to activate Joint Task Force-Homeland Defense, augment its forces with Reserve component units, and enhance regional defense capabilities. These measures would mitigate risk in a China scenario and reaffirm US sovereignty in the Pacific. With further DPRK missile and nuclear tests expected, launching this operation would be a proportionate response. The Secretary of Defense must now direct planning for Operation Noble Eagle-Pacific. [ABSTRACT FROM AUTHOR]

Copyright of Rouya Turkiyyah is the property of Insight Turkey and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Taking into account the uncertainty of the enemy's air actions during the organization of assets protection from their strikes is a decisive factor in the successful task fulfillment by air defense forces. The impact of the enemy's air actions uncertainty is assessed by the task non-fulfillment risks by air defense forces to protect assets from enemy's strikes. The article describes the method of determining the task non-fulfillment risks by air defense forces based on the use of a fuzzy-multiple approach. The risk is advisable to be taken into account together with the results of evaluating the combat effectiveness of air defense forces when making decisions on the organization of assets protection from the enemy's air attack. [ABSTRACT FROM AUTHOR]

Based on a large section drilling and blasting excavation project, the dynamic response characteristics of civil air defense tunnels are analyzed by combining field monitoring and numerical simulation. The dynamic response features include particle vibration velocity, main frequency, displacement, and stress, and the stability criterion of the tunnel is analyzed. A safety criterion model based on the ultimate tensile strength of materials is established. The results show that the frequency of the X, Y, and Z directions is mainly distributed in 90-140 Hz. The effective stress increases first and then decreases along the axis of the roadway. The stress near the explosion source is large and the relative reduction is also large. By fitting the relationship between blasting vibration velocity and maximum principal stress, the safe vibration velocity criterion based on tensile strength is obtained, and the safe threshold of vibration velocity is 19.62 cm/s. It can be assumed that blasting does not affect the structure. [ABSTRACT FROM AUTHOR]

Taiwan's 2024 election resulted in the DPP breaking the "two term curse" and retaining the presidency for a third consecutive term despite a vigorous disinformation campaign by China. As polls predicted, current vice-president William Lai Ching-te and running mate Hsiao Bi-khim won with a little over 40 percent of the vote besting KMT candidate Hou Yu-ih's 33.49 percent and the TPP's Ko Wenje at 26.49 percent, Iii the Legislative Yuan, the KMT won 52 seats, the DPP 51, and eight for the TPP, leaving the TPP with the balance of power. China responded with shows of force, changing a flight path that further constricts the pre-warning and reaction time for Taiwan's air defense, and persuading Nauru to break diplomatic ties with Taiwan in favor of recognizing China. [ABSTRACT FROM AUTHOR]

Benefit–cost analyses are critical to support U.S. agencies' programmatic decision making. These analyses are particularly challenging when one of the benefits is adversary deterrence. This paper presents a framework for calculating the value of deterrence related to countermeasures implemented to mitigate an attack by an adaptive adversary. We offer an approach for partitioning the benefit of countermeasures into three components: (1) threat reduction (deterrence), (2) vulnerability reduction, and (3) consequence mitigation. The benefit of a countermeasure is measured by the expected value of countermeasure implementation (EVCI) attributable to a specific countermeasure. It is based on the concept of expected value of imperfect control, defined as the difference in the expected values of alternatives with and without countermeasures. The EVCI represents all the benefits of implementing the countermeasure and is derived from three sources: (1) changes in attack probability (threat reduction from deterrence), (2) changes in detection probability (vulnerability reduction), and (3) changes in the distribution of attack outcomes (consequence mitigation). We partition the EVCI and estimate the portion attributable to each of these three sources to quantify the unique benefit of each. We provide two applications of the partitioning methodology using examples from the published literature that examine countermeasures designed to protect commercial aircraft against man-portable air defense systems. The proposed framework provides an approach for explicitly accounting separately for deterrence, vulnerability reduction, and consequence mitigation in benefit–cost analyses. It provides quantifiable insights into how countermeasures reduce terrorism risk. Funding: This material is based upon work supported by the U.S. Department of Homeland Security under [Grant Award 22STESE00001-02-00]. The views and conclusions contained in this document are those of the authors and should not be interpreted as necessarily representing the official policies, either expressed or implied, of the U.S. Department of Homeland Security. This award was made to Northeastern University and the University of Southern California is a sub-awardee. This work was also supported by the National Science Foundation [Grant 2027296] awarded to Decision Research. [ABSTRACT FROM AUTHOR]

The next generation of low observable (LO) unmanned combat aerial vehicle (UCAV) with highly autonomy to implement a penetration mission requires advanced methods for flyable and safe route planning (i.e., respecting physical capability of vehicle and threat coverage by hostile air defense radars) at a real‐time manner. Currently, the main challenge of real‐time route planning for LO UCAV is to achieve computationally efficiency under dynamic (pop‐up/moving) threats by air defense radars. In this paper, a real‐time planning paradigm in compliance with complex penetration requirements is proposed, and a complete modeling of route planning for LO UCAV's penetration as an optimal control problem is designed. The paper at first devises a direct method to transform the optimal control problem into a nonlinear programming (NLP) problem and then solves the formulated NLP problem under a moving planning horizon. The proposed method can give computationally efficient route planning results for LO UCAV's penetration under multiple kinds of radar threats. Numerical test results based on F‐16 uninhabited platform demonstrate the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]