Visual SLAM in dynamic environments based on object detection

A great number of visual simultaneous localization and mapping (VSLAM) systems need to assume static features in the environment. However, moving objects can vastly impair the performance of a VSLAM system which relies on the static-world assumption. To cope with this challenging topic, a real-time and robust VSLAM system based on ORB-SLAM2 for dynamic environments was proposed. To reduce the influence of dynamic content, we incorporate the deep-learning-based object detection method in the visual odometry, then the dynamic object probability model is added to raise the efficiency of object detection deep neural network and enhance the real-time performance of our system. Experiment with both on the TUM and KITTI benchmark dataset, as well as in a real-world environment, the results clarify that our method can significantly reduce the tracking error or drift, enhance the robustness, accuracy and stability of the VSLAM system in dynamic scenes.     

新型防空武器系统抗击CM建模与仿真

在分析巡航导弹技术、战术特点的基础上,给出了抗击CM的基本要求,结合新型武器系统的特点提出了抗击作战的数学模型,并通过仿真实验验证了武器系统抗击巡航导弹作战的可用性与高效性,为我新型防空武器系统抗击CM作战的效能评估提供了必要的方法和依据。     

Emergency transshipment in decentralized dealer networks: When to send and accept transshipment requests

While there has been significant previous literature on inventory transshipment, most research has focused on the dealers' demand filling decision (when to fill transshipment requests from other dealers), ignoring the requesting decision (when to send transshipment requests to other dealers). In this paper we develop optimal inventory transshipment policies that incorporate both types of decisions. We consider a decentralized system in which the dealers are independent of the manufacturer and of each other. We first study a network consisting of a very large number of dealers. We prove that the optimal inventory and transshipment decisions for an individual dealer are controlled by threshold rationing and requesting levels. Then, in order to study the impact of transshipment among independent dealers in a smaller dealer network, we consider a decentralized two‐dealer network and use a game theoretic approach to characterize the equilibrium inventory strategies of the individual dealers. An extensive numerical study highlights the impact of the requesting decision on the dealers' equilibrium behavior in a decentralized setting. © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2006     

舰空导弹武器系统软件靶场综合测试分析

针对舰空导弹武器系统的特点以及舰空导弹武器系统软件定型试验的现状,指出了舰空导弹武器系统软件靶场测试的必要性、特殊性。通过靶场软件测试综合试验,总结了舰空导弹武器系统软件靶场定型的试验方法。并指出了靶场软件测试的发展方向。     

线导+尾流自导鱼雷射击阵位优化研究

在目标运动要素未知的条件下,方位导引法是线导鱼雷常用的导引方法,尾流自导鱼雷的制导技术要求鱼雷必须满足一定的角度进入目标尾流,才能发现尾流并跟踪击毁目标.线导如何导引鱼雷满足进入尾流角的要求,是急需研究的问题.通过分析和仿真得出鱼雷满足进入尾流角要求时本艇阵位与目标速度和舷角之间的关系,并从技术角度对其射击阵位进行了优化分析及仿真,对线导 尾流自导鱼雷的作战使用具有一定的指导意义.     

Approximation algorithms for minimizing total weighted completion time of orders on identical machines in parallel

We consider the problem of scheduling orders on identical machines in parallel. Each order consists of one or more individual jobs. A job that belongs to an order can be processed by any one of the machines. Multiple machines can process the jobs of an order concurrently. No setup is required if a machine switches over from one job to another. Each order is released at time zero and has a positive weight. Preemptions are not allowed. The completion time of an order is the time at which all jobs of that order have been completed. The objective is to minimize the total weighted completion time of the orders. The problem is NP‐hard for any fixed number (≥2) of machines. Because of this, we focus our attention on two classes of heuristics, which we refer to as sequential two‐phase heuristics and dynamic two‐phase heuristics. We perform a worst case analysis as well as an empirical analysis of nine heuristics. Our analyses enable us to rank these heuristics according to their effectiveness, taking solution quality as well as running time into account. © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2006     

AN ENDOGENOUS GROWTH MODEL OF CAPITAL AND ARMS ACCUMULATION

This paper attempts to examine the effect of an anticipated foreign military threat on the steady‐state growth rate and the transitional behavior of the economy. The modeling strategy follows the Sandler and Hartley (1995 Sandler, T. and Hartley, K. 1995. The Economics of Defense, Cambridge: Cambridge University Press.  [Google Scholar]) and Dunne et al. (2005 Dunne, J.P., Smith, R.P. and Willenbockel, D. 2005. Models of military expenditure and growth: a critical review. Defence and Peace Economics, 16: 449–461. [Taylor & Francis Online], [Web of Science ®] , [Google Scholar]) viewpoints to emphasize the role of national defense in affecting growth from the perspective of both the demand and the supply sides. We thus combine the public capital version of endogenous growth with a framework of competitive arms accumulation. It is found that the key factor determining the steady state and the transitional effects of a rise in the foreign military threat on the home weapon–capital ratio, the consumption–capital ratio, and the rate of economic growth, is the degree of relative risk aversion.     

TERRORIST THREATS AND TRANSITIONAL DYNAMICS IN AN OVERLAPPING GENERATIONS MODEL

Previous research has shown that the duration of a civil war is in part a function of how it ends: in government victory, rebel victory, or negotiated settlement. We present a model of how protagonists in a civil war choose to stop fighting. Hypotheses derived from this theory relate the duration of a civil war to its outcome as well as characteristics of the civil war and the civil war nation. Findings from a competing risk model reveal that the effects of predictors on duration vary according to whether the conflict ended in government victory, rebel victory, or negotiated settlement.     

Country survey IX: Spain

From the early 1980s Spain embarked on a wide‐ranging process of military reform, from organisational changes to defence industrial policies. Investment in military equipment was set to grow, policies were drawn up to foster the domestic defence industrial base, defence R&D rocketed, and Spain joined a myriad of international arms development programmes. Yet, by 1991 the process of reform had run out of steam. Expenditure planning proved unreliable, and firms suffered from sharp cutbacks in procurement expenditure. The model of defence industrial growth sketched in the mid‐1980s had floundered. The Spanish case provides an example of how the quest to maximise defence procurement from domestic sources can fall victim to industrial and budgetary constraints. Spanish defence producers are now becoming increasingly intertwined with foreign defence companies.     

THE DEFENCE SPENDING–EXTERNAL DEBT NEXUS IN ETHIOPIA

The aim of this paper is to examine the impact of defence spending and income on the evolution of Ethiopia’s external debt over the period 1970–2005. Using the bounds test approach to cointegration and Granger causality tests, we find a long run and a causal relationship between external debt, defence spending and income. Defence spending had a positive and a significant impact on the stock of external debt while income had a negative and a statistically significant impact on external debt. Our findings suggest that an increase in defence spending contributes to the accumulation of Ethiopia’s external debt, while an increase in economic growth helps Ethiopia to reduce its external debt.